Antibody-dependent enhancement Although antibodies are generally protective and beneficial, the ADE phenomenon is documented for dengue virus and other viruses. In SARS-CoV infection, ADE is mediated by the engagement of Fc receptors (FcRs) expressed on different immune cells, including monocytes, macrophages and B cells5,6. Pre-existing SARS-CoV-specific antibodies may thus promote viral entry into FcR-expressing cells (Fig. 1b). This process is independent of ACE2 expression and endosomal pH and proteases, suggesting distinct cellular pathways of ACE2-mediated and FcR-mediated viral entry6. There is no evidence that ADE facilitates the spread of SARS-CoV in infected hosts. In fact, infection of macrophages through ADE does not result in productive viral replication and shedding7. Instead, internalization of virus–antibody immune complexes can promote inflammation and tissue injury by activating myeloid cells via FcRs5. Virus introduced into the endosome through this pathway will likely engage the RNA-sensing Toll-like receptors (TLRs) TLR3, TLR7 and TLR8 (Fig. 1c). Uptake of SARS-CoV through ADE in macrophages led to elevated production of TNF and IL-6 (ref.5). In mice infected with SARS-CoV, ADE was associated with decreased levels of the anti-inflammatory cytokines IL-10 and TGFβ and increased levels of the pro-inflammatory chemokines CCL2 and CCL3 (ref.8). Furthermore, immunization of non-human primates with a modified vaccinia Ankara (MVA) virus encoding the full-length S protein of SARS-CoV promoted activation of alveolar macrophages, leading to acute lung injury9. Protective versus pathogenic antibodies Multiple factors determine whether an antibody neutralizes a virus and protects the host or causes ADE and acute inflammation. These include the specificity, concentration, affinity and isotype of the antibody. Viral vector vaccines encoding SARS-CoV S protein and nucleocapsid (N) protein provoke anti-S and anti-N IgG in immunized mice, respectively, to a similar extent. However, upon re-challenge, N protein-immunized mice show significant upregulation of pro-inflammatory cytokine secretion, increased neutrophil and eosinophil lung infiltration, and more severe lung pathology8. Similarly, antibodies targeting different epitopes on the S protein may vary in their potential to induce neutralization or ADE. For example, antibodies reactive to the RBD domain or the HR2 domain of the S protein induce better protective antibody responses in non-human primates, whereas antibodies specific for other S protein epitopes can induce ADE10. In vitro data suggest that for cells expressing FcRs, ADE occurs when antibody is present at a low concentration but dampens at the high-concentration range. Meanwhile, increasing antibody concentrations promotes SARS-CoV neutralization by blocking viral entry into host cells6. For other viruses, high-affinity antibodies capable of blocking receptor binding tend to not induce ADE. In the ‘multiple hit’ model of neutralization, the virus-blocking effect correlates with the number of antibodies coating the virion, which is collectively affected by antibody concentration and affinity11. Monoclonal antibodies with higher affinity for the envelope (E) protein of West Nile Virus (WNV) induced better protection in mice receiving a lethal dose of WNV11. For a given concentration of antibody and a specific targeting domain, the stoichiometry of antibody engagement on a virion is dependent on the strength of interaction between antibody and antigen. ADE is induced when the stoichiometry is below the threshold for neutralization. Therefore, higher affinity antibodies can reach that threshold at a lower concentration and mediate better protection11. Antibody isotypes control their effector functions. IgM is considered more pro-inflammatory as it activates complement efficiently. IgG subclasses modulate immune responses via the engagement of different FcRs. Most FcγRs signal through ITAMs, but FcγRIIb contains an ITIM on its cytoplasmic tail that mediates an anti-inflammatory response. Ectopic expression of FcγRIIa and FcγRIIb, but not of FcγRI or FcγRIIIa, induced ADE of SARS-CoV infection6. Allelic polymorphisms in FcγRIIa are associated with SARS pathology, and individuals with an FcγRIIa isoform that binds to both IgG1 and IgG2 were found to develop more severe disease than individuals with FcγRIIa that only binds to IgG2 (ref.12). Vaccine approaches It is crucial to determine which vaccines and adjuvants can elicit protective antibody responses to SARS-CoV-2. Previous studies have shown that the immunization of mice with inactivated whole SARS-CoV13, the immunization of rhesus macaques9 with MVA-encoded S protein and the immunization of mice with DNA vaccine encoding full-length S protein14 could induce ADE or eosinophil-mediated immunopathology to some extent, possibly owing to low quality and quantity of antibody production. Additionally, we need to consider whether a vaccine is safe and effective in aged hosts. For instance, double-inactivated SARS-CoV vaccine failed to induce neutralizing antibody responses in aged mice13. Furthermore, although an alum-adjuvanted double-inactivated SARS-CoV vaccine elicited higher antibody titres in aged mice, it skewed the IgG subclass toward IgG1 instead of IgG2, which was associated with a T helper 2 (TH2)-type immune response, enhanced eosinophilia and lung pathology13. By contrast, studies in mice showed that subunit or peptide vaccines that focus the antibody response against specific epitopes within the RBD of the S protein conferred protective antibody responses3. In addition, live attenuated SARS-CoV vaccine induced protective immune responses in aged mice15. Routes of vaccine administration can further affect vaccine efficacy. Compared with the intramuscular route, intranasal administration of a recombinant adeno-associated virus vaccine encoding SARS-CoV RBD induced significantly higher titres of mucosal IgA in the lung and reduced lung pathology upon challenge with SARS-CoV3. Concluding remarks There are now multiple vaccine candidates (including nucleic acid vaccines, viral vector vaccines and subunit vaccines) in the preclinical and clinical trial stages as researchers and institutes from all over the world come together to accelerate the development of a SARS-CoV-2 vaccine. Recent studies of antibody responses in patients with COVID-19 have associated higher titres of anti-N IgM and IgG at all time points following the onset of symptoms with a worse disease outcome16. Moreover, higher titres of anti-S and anti-N IgG and IgM correlate with worse clinical readouts and older age17, suggesting potentially detrimental effects of antibodies in some patients. However, 70% of patients who recovered from mild COVID-19 had measurable neutralizing antibodies that persisted upon revisit to the hospital18. Thus, insights gained from studying the antibody features that correlate with recovery as opposed to worsening of disease will inform the type of antibodies to assess in vaccine studies. We argue that ADE should be given full consideration in the safety evaluation of emerging candidate vaccines for SARS-CoV-2. In addition to vaccine approaches, monoclonal antibodies could be used to tackle this virus. Unlike vaccine-induced antibodies, monoclonal antibodies can be engineered with molecular precision. Safe and effective neutralizing antibodies could be produced on a mass-scale for delivery to populations across the world in the coming months. Reference & Source information: https://www.nature.com/ Read More on:

Immunomodulatory role of Vitamin D should be further investigated. Methods: We reviewed the literature about the immunomodulatory role of Vitamin D collecting data from the databases Medline and Embase. Results Vitamin D proved to interact both with the innate immune system, by activating Toll-like receptors (TLRs) or increasing the levels of cathelicidins and β-defensins, and adaptive immune system, by reducing immunoglobulin secretion by plasma cells and pro-inflammatory cytokines production, thus modulating T cells function. Promising results have been extensively described as regards the supplementation of vitamin D in respiratory tract infections, autoimmune diseases and even pulmonary fibrosis. Conclusions In this review, we suggest that vitamin D supplementation might play a role in the prevention and/or treatment to SARS-CoV-2 infection disease, by modulating the immune response to the virus both in the adult and pediatric population. Discussion The demographics of the Covid-19 outbreak proves that elderly males, with or without comorbidities, are the most affected across all populations. The available data on the epidemic are also showing a lesser involvement of vast areas lying in the tropics. Although this could easily relate to the lower median age of the population of developing countries, it is harder to make such an inference when looking at the markedly slow march of the Covid-19 epidemic in countries of the southern hemisphere, such as Australia. Just recently, it has been directly hypothesized that vitamin D supplementation could be used as a therapeutic combination in Covid-19, based on the epidemiology of the disease, and on the decreased vitamin D status observed in calves infected with bovine coronavirus . In the emergency setting that followed the spread of the Covid-19 pandemic new therapeutics have been empirically administered on the basis of former experience in the management of diseases sharing a few similarities with Covid-19-associated ARDS, such as inflammatory autoimmune diseases. A growing interest in the role of tocilizumab, a monoclonal antibody directed against interleukin-6 (IL-6), which is commonly used in the treatment of rheumatoid arthritis, ensued the publication of works regarding its potential use in the prevention of severe cytokine release syndromes, such as in Car-T cell treated pediatric oncologic patients. This so-called cytokine storm has been postulated and confirmed as the main responsible for the lethal pulmonary involvement that is being observed in Covid-19 and was thoroughly studied in former 2009 SARS epidemic. In order to confirm tocilizumab therapeutic potential in ventilator-assisted Covid-19 patients, a clinical trial is currently ongoing in China and in Europe. Just recently, normal to high blood levels of vitamin D proved to act synergistically with tocilizumab in patients with rheumatoid arthritis by suppressing IL-6 enhanced osteocyte-mediated osteoclastogenesis and reducing disease activity. Although the data on Covid-19 survivors are still lacking, a further downside of the pandemic might be the development of pulmonary fibrosis, which has been widely described as a common complication of ARDS [61]. Here, vitamin D supplementation before and after the infection could play an antifibrotic role that yet need to be delved into.Finally, we would highlight some points that should be further investigated. There is, in fact, a vast literature that shows how obesity in children is closely related with low levels of vitamin D, reaching the prevalence of 92% in the United States. Interestingly, in a recent review, it was also showed that increased adipose tissue, altered adipocyte function and development of adipocyte hypertrophy is linked to an altered adipokine secretion profile, with increase in TNF-alpha, IL-6, and IL-1b levels. Even more interestingly, the study proved that patients receiving long-term vitamin D supplementation had a reduction in adipose tissue inflammation by inhibition of TNF-alpha activity . Prepubertal children have generally lower androgen levels, with an elevated estrogen to androgen ratio. It has been demonstrated that low estrogen levels are related with an increased IL-1beta, IL-6, and TNF, increased activity of Th1 cells and high androgen levels are related with an increase in IL-1beta, IL-6, and a reduction in TNF, IFN-gamma, IL-4, IL-5, GATA3. It is also clear that sex hormones can differentially influence, along with other genetic polymorphisms and environmental factors, development of innate and adaptive immune responses. In a murine model, the hormonal changes of puberty upregulated the expression of genes associated with innate and adaptive immune responses in males and females, respectively. It has also been demonstrated that high levels of vitamin D seem to reduce aromatase activity (which is in turn increased by high levels of pro-inflammatory cytokines levels), thus containing the effects related to increased peripheral estrogen metabolism, such as B cell overactivity. That means that low levels of vitamin D can increase the risk of developing autoimmune diseases in young women. Conclusion Till date, only one recent paper addressed the relationship between vitamin D levels and the clinical outcomes of patients with Covid-19. The author conducted a multinomial logistic regression to explore the association between serum 25(OH)D level and clinical outcomes of 212 cases with laboratory-confirmed infection of SARS–CoV-2. Interestingly, serum 25(OH)D proved to be a predictor of severe (OR 0.126, p < 0.001) and critical (OR 0.051, p < 0.001) Covid-19. A recent review proposes the supplementation of vitamin D in Covid-19 patients based on the promising findings of RCTs conducted in other viral infections. According to the emerging relationship between vitamin D status and alleged Covid-19 infection, vitamin D supplementation has already been proposed elsewhere. Although we do not assume that vitamin D plays a role in the pathogenesis of Covid-19, we do believe that its putative role in preventing or even treating the disease urgently needs to be further addressed. At the moment of writing, an interventional randomized clinical trial has been proposed at the University of Granada, with enrollment of 200 participants, proposing vitamin D supplementations (a single dose of 25,000 UI of vitamin D) in preventing and treating mild forms of suspected Covid-19. In a recent paper, it is assumed that vitamin D prophylaxis (without overdosing) could reduce, especially in patients with hypovitaminosis D, the severity of illness caused by SARS–CoV-2. The importance of treating the hypovitaminosis D along with an early nutritional supplementation has been highlighted for the potential preventing role of malnutrition sequelae in these patients. On the basis of the possible direct and indirect effect of vitamin D on immune system and cytokines production, we speculate a possible influence of this vitamin on the immunologic response to the virus and/or a modulating effect on the drugs being administered, namely hydroxychloroquine and anti-IL 6 and anti-IL 1 agents. Reference & Source information: https://link.springer.com/ Read More on:

Positive-sense RNA viruses hijack intracellular membranes that provide niches for viral RNA synthesis and a platform for interactions with host proteins. However, little is known about host factors at the interface between replicase complexes and the host cytoplasm. We engineered a biotin ligase into a coronaviral replication/transcription complex (RTC) and identified >500 host proteins constituting the RTC microenvironment. siRNA-silencing of each RTC-proximal host factor demonstrated importance of vesicular trafficking pathways, ubiquitin-dependent and autophagy-related processes, and translation initiation factors. Notably, detection of translation initiation factors at the RTC was instrumental to visualize and demonstrate active translation proximal to replication complexes of several coronaviruses. Collectively, we establish a spatial link between viral RNA synthesis and diverse host factors of unprecedented breadth. Our data may serve as a paradigm for other positive-strand RNA viruses and provide a starting point for a comprehensive analysis of critical virus-host interactions that represent targets for therapeutic intervention. Results Engineering the BirAR118G biotin ligase into the MHV replicase transcriptase complex To insert the promiscuous biotin ligase BirAR118G as an integral subunit of the MHV RTC, we used a vaccinia virus-based reverse genetic system (Coley et al., 2005; Eriksson et al., 2008) to generate a recombinant MHV harboring an in-frame fusion of myc-tagged BirAR118G to nsp2. MHV-BirAR118Gnsp2 retained the cleavage site between nsp1 and BirAR118G, while a deleted cleavage site between BirAR118G and nsp2 ensured the expression of a BirAR118G-nsp2 fusion protein (Figure 1a). This strategy was chosen because it was recently employed by Freeman et al. for a fusion of green fluorescent protein (GFP) with nsp2 and represents the only known site tolerating large insertions within the MHV replicase polyprotein (Freeman et al., 2014). MHV-BirAR118G-nsp2 replicated to comparable peak titers and replication kinetics as the parental wild-type MHV-A59 (Figure 1b). MHV-GFP-nsp2, which was constructed in parallel and contained the coding sequence of EGFP (Freeman et al., 2014) instead of BirAR118G, was used as a control and also reached wild-type virus peak titers, with slightly reduced viral titers at 9 hr post- infection (h.p.i.) compared to MHV-A59 and MHV-BirAR118Gnsp2 (Figure 1b). Western blot analysis confirmed that the BirAR118G-nsp2 fusion protein is specifically detected in MHV-BirAR118G-nsp2-infected cells and that the BirAR118G biotin ligase remains fused to nsp2 during MHV-BirAR118G-nsp2 infection (Figure 1—figure supplement 1). To further confirm the accommodation of BirAR118G within the viral RTC, MHV-A59-, MHV-BirAR118G-nsp2-, and mock-infected L929 fibroblasts were visualized using indirect immunofluorescence microscopy. BirAR118G-nsp2 remained strongly associated with the MHV RTC throughout the entire replication cycle, as indicated by the co-localization of BirAR118G-nsp2 with established markers of the MHV replicase, such as nsp2/3 and nsp8 (Figure 1c, Figure 1—figure supplement 2, Figure 1—figure supplement 3). This observation corroborates previous studies demonstrating that nsp2, although not required for viral RNA synthesis, co-localizes with other nsps of the coronaviral RTC (Schiller et al., 1998; Hagemeijer et al., 2010; Graham et al., 2005). Importantly, by supplementing the culture medium with biotin, we could readily detect biotinylated proteins with fluorophore-coupled streptavidin that appeared close to the MHV RTC throughout the entire replication cycle in MHV-BirAR118G-nsp2-infected cells,represent the mean and SEM of three independent experiments, each performed in quadruplicate. (c) Immunofluorescence analysis of MHV-BirAR118Gnsp2-mediated biotinylation of RTC-proximal factors. L929 cells were infected with MHV-BirAR118G-nsp2 (MOI = 1) in medium supplemented with 67 mM biotin. Cells were fixed 15 hr post infection (h.p.i.) and processed for immunofluorescence analysis with antibodies directed against the BirAR118G (antimyc), the viral replicase (anti-nsp2/3) and biotinylated factors (streptavidin). Nuclei are counterstained with DAPI. Z-projection of deconvolved z-stacks acquired with a DeltaVision Elite High-Resolution imaging system are shown. Scale bars: 20 mm; insets 5 mm. (d) Ultrastructural analysis of MHV-APEX2- nsp2 infection. L929 cells were infected with MHV-APEX2-nsp2 and MHV-A59 (MOI = 2), or mock infected. At 10 h.p.i., cells were fixed, stained with DAB and processed for electron microscopy investigations. Representative low (scale bar: 10 mm) and high magnifications (scale bar: 2 mm) are displayed Reference & Source information: https://elifesciences.org/ Read More on :

Interactive Cell Cycle Control: G1/S Checkpoint Pathway Cell cycle arrest provides time crucial for repair of DNA damage, preserving genomic integrity. Growth arrest activates through checkpoint pathways that delay cell cycle progression. The balance between cell differentiation and proliferation is regulated transcriptionally; in the cell cycle the G1 to S-phase transition is the primary control point. Only prior to this can cells be directed to differentiation, otherwise they progress to the proliferative cycle autonomously. Interactive Apoptosis Pathway Apoptosis (programmed cell death) is characterized by cell shrinkage, membrane blebbing, phagocytic engulfment of the fragmented cell, DNA fragmentation and mitochondrial release of cytochrome C. Tightly regulated termination is essential to cull unneeded, aging, mutated, or infected cells. Dysregulation of death/survival signals in the apoptotic pathway is implicated in a broad range of human diseases. Controlling fidelity of the apoptotic pathways may lead to new methods to treat challenging diseases. Interactive mTOR Signaling Pathway The mammalian target of rapamycin (mTOR) signaling pathway integrates intracellular and extracellular signals to regulate cell metabolism, growth, proliferation and survival. This pathway is activated during a range of cellular processes (tumor formation, angiogenesis, insulin resistance, adipogenesis, T-lymphocyte activation, etc.) and is dysregulated in diseases such as cancer and diabetes. mTOR inhibitors such as rapamycin and its analogues are used in treatment of solid tumors, organ transplantation, circulatory disease and rheumatoid arthritis. Interactive Angiogenesis Pathway Angiogenesis is the process of creating new blood vessels from preexisting blood vessels. This process is essential for healing, growth, development, maintenance, and wound repair in an organism. The angiogenesis pathway is controlled by balancing stimulatory and inhibitory factors. When this balance is disrupted, abnormal blood vessel growth occurs. Overgrowth or lack of growth may be an underlying contributor to medical conditions including cancer, skin diseases, age-related blindness, diabetic wounds that do not heal, heart disease, and strokes. Interactive Notch Signaling Pathway The Notch signaling pathway is an evolutionarily conserved pathway operating in multicellular organisms. This pathway plays a significant role in cell differentiation during embryonic development and maintenance of adult tissue homeostasis. Notch receptors are single-pass transmembrane proteins that bind in calcium-dependent, non-covalent interactions with Notch proteins to activate signaling. This pathway is of enduring interest to pharmaceutical researchers due to its regulatory effects on neurological, cell growth, and cardiovascular systems related to human diseases. Notch signaling promotes cellular proliferation during neurogenesis, and is inhibited by the protein Numb to promote neural differentiation. Key mutations in Notch receptors leader to deposition of proteins common in leukemias and lymphomas, and both Notch receptor and ligand mutations have been tied to disorders including Aagille syndrome and pathologies of the cerebral arteries. Interactive Jak/Stat Signaling Pathway The Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway cascades to transduce cellular signals for development and homeostasis. The JAK-STAT signaling pathway is a critical component of cytokine receptor and growth factor systems regulating growth, survival, differentiation, and activation of the immune system. JAK activation plays a role in specific cellular processes such as cell proliferation, cell migration and apoptosis. Mutational downregulation of the JAK/STAT pathway affects hematopoiesis, immune system development, adipogenesis, and other processes. Upregulation caused by specific mutations contribute to inflammatory disease, erythrocytosis, and cancers, among other disorders. Interactive NFKappa Pathway Nuclear factor-kB (NF-kB)/Rel proteins control genes involved in inflammation, innate and adaptive immunity, B-cell development inflammation, and stress responses. In the canonical NF-kB pathway, IkB proteins bind and inhibit NF-kB/Rel proteins. A host of receptors activate an IKK complex that phosphorylates IkB proteins, triggering ubiquitination and proteasomal degradation, liberating NF-kB/Rel complexes which ultimately migrate to the nucleus to upregulate target gene expression. In the noncanonical pathway, specific receptor signaling activates kinase NIK, which activates IKKa complexes that phosphorylate residues in NF-kB2 p100. This process promotes ubiquitination and proteasomal cleavage to NF-kB2 p52. NF-kB p52/RelB complexes move to the nucleus to induce target gene expression CREB Pathway Extracellular stimuli summon changes in gene expression in target cells by activating intracellular protein kinase cascades that phosphorylate nuclear transcription factors. Transcription factor CREB1 (cyclic AMP (cAMP) responsive element binding protein 1) activates transcription of the target genes in response to a wide array of stimuli, including peptide hormones, growth factors, and neuronal activity. CREB1 is essential to a variety of cellular processes, including proliferation, differentiation, and adaptive responses. CREB proteins are critical for learning and memory and contribute to neuronal adaptation to drugs of abuse and hormonal control of metabolic processes, including regulation of gluconeogenesis by hormones glucagon and insulin. Reference & source information: https://www.abcepta.com/

One of the article published in NCBI This paper reports for the first time, the outcomes of Ayurvedic intervention in a COVID-19 patient with severe hypoxia requiring supportive oxygen therapy. Patient developed fever, severe cough, loss of smell, loss of taste, nasal block, anorexia, headache, body ache, chills, and fatigue and was hospitalised when she developed severe breathing difficulty. Later, she tested positive for COVID-19 by RT PCR. The patient sought Ayurvedic treatment voluntarily when her SPO2 remained at 80% even after being given oxygen support. With COVID-19 being self limiting in majority of patients, it is not possible to draw definite conclusions about efficacy of any medical intervention with data from a single patient. However, this case points out the potential for Ayurveda to be considered as a first line and cost effective intervention even in COVID-19 patients with severe hypoxia. The oxygen saturation of the patient remained at 80% even after providing oxygen and Allopathic medications. After administration of Ayurvedic medicines, the oxygen saturation of the patient normalised within a day and oxygen support could be gradually withdrawn. The patient was clinically symptom free after just two days of Ayurvedic treatment. The remaining one week of her stay in the hospital was uneventful. On the basis of this observation, we propose that Ayurvedic treatment may be considered even in moderately severe COVID-19 patients on oxygen support and its role in preventing the progress of the disease to more severe stage should be investigated by conducting larger studies. The classical indications of the medicines administered to this patient point to their relevance in the management of COVID-19. As discussed in the section on diagnosis, the patient presented with symptoms indicating vātakaphapradhānasannipātajvara with indications of increasing pitta dominance. The patient was administered ṣaḍaṅgapānīyaṃ (medicated herbal water made of six herbs) for dīpanapācana (stimulating digestion and metabolism). Guḍūcī (Tinospora cordifolia) was added to make the combination balanced in addressing the imbalance of all three doṣas. Ṣaḍaṅgapānīya has a specific action on pitta in fevers [19] while guḍūcī can also additionally act on vāta and kapha apart from pitta [20]. Considering the fast progression of breathlessness and hypoxia, with the subjective experience of inability to breathe, the blockage/covering (avarana) of vāta in the āmāśaya (upper gastrointestinal tract) was considered. Breathlessness and cough are mentioned as symptoms of this condition termed as āmāśayagatavāta and ṣaḍdharaṇacūrṇa has been specifically indicated in this context [12,13]. Breathing difficulty caused by obstruction of vāta by kapha has also been clearly mentioned in the texts to be originating in the āmāśaya [19]. On the basis of this clinical judgement, ṣaḍdharaṇacūrṇa was administered for seven days. Sūkṣmatriphalā, which is a combination of triphalā with kajjalī (combination of mercury and sulphur) is a rasāyana (immunity bolstering agent)[21]. It is widely used in management of upper and lower respiratory tract. This medicine was administered to prevent infection and support the immune system of the patient. Kanakāsavam was also administered for relief from dyspnoea, which is a main indication of this formulation. It works as an expectorant and dilates the airways [22]. The above medicines were given in divided small doses at short intervals (see Table 1) based on the principle of frequent drug administration (muhurmuhur) in poisoning, vomiting, thirst, hiccough, dyspnoea and cough[19]. Indukāntaṃ kaṣāyaṃ was administered for strengthening the digestion and metabolism, to control and prevent recurrence of fever and also to enhance the strength of the patient [23]. Indukāntaṃ kaṣāyaṃ is indicated in diseases with dominance of vāta, depletion (kṣaya), intermittent fever (nimnonnatajvara) and especially for improving strength (bala). A previous study exploring the effects of Indukāntaṃ Ghrtaṃ (the same decoction cooked in ghee) as an adjuvant in cancer chemotherapy reported it to be capable of inducing leukopoiesis as well as activation of non-specific and specific immune mechanisms of the host [24]. Ayurveda recognises the causative role of a virus as an external agent in diseases like COVID-19. COVID-19 could be classified as an āgantukajvara (fever of exogenous origin) caused by bhūtābhiṣaṅga (bhūta also means virulent microbes), the contact with virulent microorganisms [14]. However, the focus of Ayurvedic treatment is on strengthening host factors like agni (digestive and metabolic functions) and bala (innate strength of body and mind) as well as restoring the balance of the doṣas (restoring functional integrity of the body) to overcome the infection and recover from the disease. Therapeutic Intervention Types of intervention (modern pharmacological) On admission (21 June 2020, around 8 pm), she was prescribed the following medicines. Therapeutic Intervention Types of intervention (modern pharmacological) On admission (21 June 2020, around 8 pm), she was prescribed the following medicines. 1. Azee (Azithromycin) 625 mg 1-0-0 2. Cefexime 200 mg 1-0-1 3. T. Dexamethasone 6 mg 1-0-0 4. T. Acetaminophen 650 mg SOS 5. T. Vitamin C 500 mg 1-0-1 6. T. Pantoprazole 40 mg 1-0-0 7.C. Becosule (Vitamin B Complex) 1-0-0 8.Syp. Grilinctus (Guaifenesin, Chlorpheniramine maleate and Ammonium chloride) 2 tsp 1-1-1 The doctors suggested the option of starting Fabiflu, but the patient declined to take this medicine. She stopped taking all the above prescribed medicines after starting the Ayurvedic treatment (22 June 2020 by 7 pm). Only Vitamin C and oxygen support was continued. Types of intervention (Ayurveda) On the evening of the second day of hospitalisation, she opted for Ayurvedic treatment by consulting Ayurvedic physician by video calling. She was administered the following Ayurvedic medicines immediately. 1. Ṣaḍaṅgapānīyaṃ with Guḍūcī 2. Ṣaḍdharaṇacūrṇa 3. Sūkṣmatriphalā 4. Kanakāsavaṃ 5.Indukāntaṃ Kaṣāyaṃ The dosing and duration of the administration of these medicines are summarised in Table 1 . The dosing and duration of the administration of these medicines are summarised in Read Full Article

The worldwide spread of COVID-19 highlights the need for an efficient approach to rapidly develop therapeutics and prophylactics against SARS-CoV-2. The SARS-CoV-2 spike protein, containing the receptor-binding domain (RBD) and S1 subunit involved in receptor engagement, is a potential therapeutic target. We describe the development of a phage-displayed single-domain antibody library by grafting naive complementarity-determining regions (CDRs) into framework regions of a human germline immunoglobulin heavy chain variable region (IGHV) allele. Panning this library against SARS-CoV-2 RBD and S1 subunit identified fully human single-domain antibodies targeting five distinct epitopes on SARS-CoV-2 RBD with subnanomolar to low nanomolar affinities. Some of these antibodies neutralize SARS-CoV-2 by targeting a cryptic epitope located in the spike trimeric interface. Collectively, this work presents a versatile platform for rapid antibody isolation and identifies promising therapeutic anti-SARS-CoV-2 antibodies as well as the diverse immogneic profile of the spike protein. It is very intriguing that the panning with SARS-CoV-2 S1 or RBD protein as antigen resulted in a substantially different spectra of antibodies. The antibodies identified from S1 panning were very diverse, covering four distinct epitopes on SARS-CoV RBD (competition groups A, B, D, and E). In contrast, most of the antibodies from RBD panning belonged to competition group A represented by n3021, which was also the most dominant clone after two rounds of panning. Furthermore, group A antibodies showed moderate competition with ACE2 for RBD binding but proved to be ineffective viral neutralizers. This phenomenon is quite different from that of SARS-CoV, in which the dominance of an antigenic loop within RBD made it relatively easy to isolate potent SARS-CoV neutralizing antibodies independent of repertoire, species, quaternary structure, and the technology used to derive the antibodies. Similarly, we previously used MERS-CoV S1 or RBD to isolate antibodies from a naive antibody library, and panning that used either of the two antigens led to dominant enrichment of antibodies that precisely targeted 90% of the receptor binding site within RBD and neutralized the virus potently. It was proposed that viruses like SARS-CoV have not yet evolved such that their membrane glycoproteins could avoid direct immune recognition of a single site critical to virus pathogenesis. It should be pointed out that the difference in the immunogenicity of RBD was observed solely based on in vitro experiments and might not correlate with humoral immune responses in vivo. In this regard, it is imperative to investigate the immunogenic characteristics of SARS-CoV-2 RBD with special attention to potentially antigenic and non-neutralizing epitopes. It is also striking that the SARS-CoV-2-specific neutralizing antibodies from competition groups D and E are incapable of competing with ACE2 for SARS-CoV-2 RBD binding. This phenomenon was rarely observed in SARS-CoV, confirming the unique immunogenic profile of SARS-CoV-2. Further investigations are needed to understand the underlying mechanisms that govern these diverse sets of neutralizing and non-neutralizing SARS-CoV-2 antibodies, which could have important implications for the development of effective vaccines. More interestingly, the group D antibodies n3088 and n3130 were found to neutralize SARS-CoV-2 by targeting a “cryptic” epitope located in the spike trimeric interface. The mAb CR3022 also recognizes this epitope but cannot neutralize SARS-CoV-2, implying the advantage of small-size single-domain antibodies to target cryptic eptiopes. Such hidden trimeric interface epitope was also observed recently in the study of influenza antibodies by our group and several other groups. It is probable that such an epitope would also be important in the study of coronaviruses, and n3088 or n3130 could be ideal for synergistically used with other SARS-CoV-2 neutralizing antibodies, especially the ACE2-competing neutralizing antibodies. Fully human single-domain antibodies offer the potential for prevention and treatment of COVID-19. First, antibodies derived entirely from human sequences would be less immunogenic than camelid or humanized nanobodies, leading to improved safety and efficacy when used in humans. Indeed, despite humanization, caplacizumab, the first nanobody approved by FDA, still contains multiple camelid residues to maintain the antigen binding affinity . Second, small size and favorable biophysical properties allow for large-scale production of single-domain antibodies within a few weeks in prokaryotic expression systems, thus enabling rapid implementation in an outbreak setting. Furthermore, single-domain antibodies could be delivered to the lung via inhalation, which could offer considerable advantages for treatment of COVID-19, including fast onset of action, low systemic exposure, and high concentration of therapeutics at the site of disease. Lastly, single-domain antibodies can be used alone or synergistically with other neutralizing antibodies. Their small size makes them ideal building blocks for generation of bispecific or multi-specific antibodies to prevent the appearance of viral escape mutants. They can also be easily engineered to further increase neutralization activity by increasing binding moieties. For instance, the trivalent nanobody ALX-0171 was found to have 6,000-fold increased neutralization potency against RSV-A and >10,000-fold against RSV-B compared to its monovalent format. In summary, we report here the development of a versatile platform for rapid isolation of fully human single-domain antibodies and their application for screening of antibodies against SARS-CoV-2. These antibodies could represent promising candidates for prophylaxis and therapy of COVID-19 and serve as reagents to facilitate vaccine development. Reference&source information: https://www.sciencedirect.com/ Read More on:

The mode of acquisition and causes for the variable clinical spectrum of coronavirus disease 2019 (COVID-19) remain unknown. We utilized a reverse genetics system to generate a GFP reporter virus to explore severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogenesis and a luciferase reporter virus to demonstrate sera collected from SARS and COVID-19 patients exhibited limited cross-CoV neutralization. High-sensitivity RNA in situ mapping revealed the highest angiotensin-converting enzyme 2 (ACE2) expression in the nose with decreasing expression throughout the lower respiratory tract, paralleled by a striking gradient of SARS-CoV-2 infection in proximal (high) versus distal (low) pulmonary epithelial cultures. COVID-19 autopsied lung studies identified focal disease and, congruent with culture data, SARS-CoV-2-infected ciliated and type 2 pneumocyte cells in airway and alveolar regions, respectively. These findings highlight the nasal susceptibility to SARS-CoV-2 with likely subsequent aspiration-mediated virus seeding to the lung in SARS-CoV-2 pathogenesis. These reagents provide a foundation for investigations into virus-host interactions in protective immunity, host susceptibility, and virus pathogenesis. We generated a SARS-CoV-2 reverse genetics system; characterized virus RNA transcription profiles; evaluated the effect of ectopically expressed proteases on virus growth; and used reporter viruses to characterize virus tropisms, ex vivo replication, and to develop a high-throughput neutralizing assay. These reagents were utilized to explore aspects of early infectivity and disease pathogenesis relevant to SARS-CoV-2 respiratory infections. Our single-cell RNA-ISH technology extended the description of ACE2 in respiratory epithelia on the basis of scRNA-seq data. Single-cell RNA-ISH detected ∼20% of upper respiratory cells expressing ACE2 versus ∼4% for scRNA-seq. Most of the RNA-ISH-detected ACE2-expressing cells were ciliated cells, not normal MUC5B+ secretory (club) cells or goblet cells. Notably, the nose contained the highest percentage of ACE2-expressing ciliated cells in the proximal airways. The higher nasal ACE2 expression-level findings were confirmed by qPCR data comparing nasal to bronchial airway epithelia. qPCR data also revealed that ACE2 amounts further waned in the more distal bronchiolar and alveolar regions. Importantly, these ACE2 expression patterns were paralleled by high SARS-CoV-2 infectivity of nasal epithelium with a gradient in infectivity characterized by a marked reduction in the distal lung (bronchioles and alveoli) Multiple aspects of the variability in SARS-CoV-2 infection of respiratory epithelia were notable in these studies. First, significant donor variations in virus infectivity and replication efficiency were observed. Notably, the variability was less in the nose than lower airways. The reason(s) for the differences in lower airway susceptibility are important but remain unclear. We identified variations in ACE2 receptor expression but not numbers of ciliated cells as potential variables. Second, variation in infectivity of a single cell type, i.e., the ciliated cell, was noted with only a fraction of ciliated cells having access to virus infected at 72 h. Third, the dominant secretory cell, i.e., the MUC5B+ club cell, was not infected in vitro or in vivo, despite detectable ACE2 and TMPRSS2 expression. Collectively, these data suggest that measurements of ACE2 and TMPRSS2 expression do not fully describe cell infectivity and that a description of other variables that mediate susceptibility to infection, including the innate immune system(s), is needed. The ACE2 receptor gradient in the normal lung raised questions focused on the initial sites of respiratory tract virus infection, the mechanisms that seed infection into the deep lung, and the virus-host interaction networks that attenuate or augment intra-regional virus growth in the lung to produce severe disease, especially in vulnerable patients experiencing chronic lung or inflammatory diseases. We speculate that nasal surfaces might be the dominant initial site for SARS-CoV-2 respiratory tract infection. First, SARS-CoV-2 RNA has been detected in aerosol particles in the range of aerodynamic sizes exhaled during normal tidal breathing. Aerosol deposition and fomite mechanical delivery deposition modeling suggest that aerosols containing virus inhaled by naive subjects achieve the highest density of deposition, i.e., highest MOI per unit surface area, in the nose. Second, the relatively high ACE2 expression in nasal specimens and the parallel high infectivity of the HNE cultures suggests the nasal cavity is a fertile site for early SARS-CoV-2 infection. Nasal infection likely is dominated by ciliated cells in the superficial epithelium, not nasal submucosal glands. Third, the nose is exposed to high but variable loads of environmental agents, producing a spectrum of innate defense responses. Hence, a portion of the variability of the clinical syndrome of COVID-19 might be affected by environmentally driven variance of nasal infectivity. Another aspect of the variability of the COVID-19 syndrome is the variable incidence and severity of lower lung disease. It is unlikely SARS-CoV-2 is transmitted to the lung by hematogenous spread, as demonstrated by the absence of infection of MVE cells and by previous reports that indicate airway cultures are difficult to infect from the basolateral surface. Theoretically, infection could be transmitted directly to lower lung surfaces by microaerosol inhalation with deposition on and infection of alveolar surfaces mediated in part by the high ACE2 binding affinity reported for SARS-CoV-2 . However, given the low amounts of ACE2 expression in alveolar cells in health, the correlated poor infectivity in vitro, and the absence of a homogeneous pattern radiographically, the importance of this route remains unclear (In contrast, it is well-known that an oral-lung aspiration axis is a key contributor to many lower airways infectious diseases. Nasal secretions are swept from the nasal surface rostrally by mucociliary clearance and accumulate in the oral cavity at a rate of ∼0.5 mL/h where they are admixed with oropharyngeal or tonsillar fluid. Especially at night, it is predicted that a bolus of relatively high titer virus is aspirated into the deep lung, either via microaspiration or as part of gastro-esophageal reflex-associated aspiration, sufficient to exceed the threshold PFU/unit surface area needed to initiate infection. Note, our data that tracheas exhibited significant viral infection in vivo suggest that small-volume microaspiration could also seed this site. Tracheal-produced virus could then also accumulate in the oropharynx via mucus clearance for subsequent aspiration into the deep lung (Quirouette et al., 2020). Oropharyngeal aspirates also contain enzymes and/or inflammatory mediators that might condition alveolar cells for infection. Aspiration of SARS-CoV-2 into the lung is consistent with the patchy, bibasilar infiltrates observed by chest CT in COVID-19 (Xu et al., 2020). Notably, robust microaspiration and gastro-esophageal aspiration are observed frequently in subjects who are at risk for more severe COVID-19 lower respiratory disease, e.g., older, diabetic, and obese subjects. Finally, our autopsy studies demonstrated patchy, segmental or subsegmental disease, consistent with aspiration of virus into the lung from the oropharynx. These speculations describing the early pathogenesis of SARS-CoV-2 upper and lower respiratory tract disease are consistent with recent clinical observations. The data from in COVID-19-positive subjects support the concept of early infection in the upper respiratory tract (0–5 d) followed by subsequent aspiration and infection of the lower lung. These authors focused on the oropharynx as a potential site of the early virus propagation. As noted above, however, a nasal-oropharyngeal axis also exists, which has two implications. First, the nasal surfaces could seed the oropharynx for infection. Second, it is likely that oropharyngeal secretions reflect a mixture of local secretions admixed with a robust contribution of nasal mucus and virus. Animal model data are also compatible with the scenario of aspiration-induced focal SARS-CoV-2 lung disease. The data of noted focal lung disease after combined intranasal versus intratracheal dosing with SARS-CoV-2 in cynomolgus monkeys. Notably, other findings in this model phenocopied our observations of human disease, e.g., early nasal shedding of virus, infection of nasal ciliated cells, and infection of AT2 and likely AT1 cells. Perhaps more definitive data describing nasal cavity seeding of the lower lung by microaspiration emanate from the studies. These investigators demonstrated in ferret models that genetically marked virus delivered to the nasal cavity more efficiently transmitted infection to the lower lungs than a virus with a distinct genetic marker delivered directly into the lungs. In addition to identifying possible microaspiration risk factors associated with COVID-19 disease severity in the elderly, diabetic, and obese, our studies provide insights into variables that control disease severity in subjects at risk because of pre-existing pulmonary disease. For example, ACE2 expression was increased in the lungs of CF patients excised at transplantation. A major cytokine that produces the muco-inflammatory CF airways environment, IL-1β, was associated in vitro with increased ACE2 expression . The clinical outcome of increased ACE2 expression in CF is not yet known. The simple prediction is that increased ACE2 expression might be associated with more frequent or severe SARS-CoV-2 disease in CF populations. However, increased ACE2 expression is reported to be associated with improved lung function by negatively regulating ACE and the angiotensin II and the angiotensin II type 1a receptor (AT1a) in models of alveolar damage (pulmonary edema) and bacterial infection . Consequently, CF subjects might exhibit reduced severity of disease once acquired. Data describing outcomes of COVID-19 in the CF populations should emerge soon. Our autopsy studies also provide early insights into the variable nature of the severity and pathogenesis related to post-COVID-19 lung health or function . Our study has identified another feature of COVID-19, i.e., the accumulation of apparently aberrantly secreted MUC5B in the alveolar region. Accumulation of MUC5B in the peripheral (alveolar) lung is characteristic of subjects who develop IPF, and polymorphisms in the MUC5B promoter associated with IPF have been reported . Future studies of the long-term natural history of SARS-CoV-2 survivors, in combination with studies delineating the cell types responsible for MUC5B secretion (AT2 versus airway cells) and genetics, e.g., MUC5B polymorphisms, might aid in understanding the long-term favorable versus fibrotic outcomes of COVID-19 disease. Our study also provides a SARS-CoV-2 infectious full-length cDNA clone for the field. Several strategies have been developed to construct stable coronavirus molecular clones, including the bacterial artificial chromosome (BAC) and vaccinia viral vector systems . In contrast, our in vitro ligation method solves the stability issue by splitting unstable regions and cloning the fragmented genome into separate vectors, obviating the presence of a full-length genome. Our in vitro ligation strategy has generated reverse genetic systems for at least 13 human and animal coronaviruses and produced hundreds of mutant recombinant viruses. In contrast to other reports , reporter recombinant SARS-CoV-2 viruses generated herein replicated to normal WT amounts in continuous cell lines, allowing for robust ex vivo studies in primary cultures. Using this infectious clone, we generated a high-throughput luciferase reporter SARS-CoV-2 assay for evaluation of viral nAbs. In line with previous reports, our data show that several SARS-CoV RBD-binding nAbs fail to neutralize SARS-CoV-2, suggesting distant antigenicity within the RBD domains between the two viruses. Although more samples are needed, early convalescent sera demonstrated ∼1.5 log variation in neutralizing titers at ∼day 30 after infection, demonstrating a need to fully understand the kinetics, magnitude, and durability of the neutralizing antibody response after a primary SARS-CoV-2 infection. The detection of low-level SARS-CoV-2 cross-neutralizing antibodies in 2003 SARS-CoV serum samples is consistent with recent studies suggesting that existence of common neutralizing epitopes between the two CoVs. Interestingly, convalescent COVID-19 sera failed to cross-neutralize SARS-CoV in vitro, suggesting cross-neutralizing antibodies might be rare after SARS-CoV-2 infection. The location of these epitopes is unknown. The nLuc recombinant viruses described herein will be powerful reagents for defining the antigenic relationships between the Sarbocoviruses, the kinetics and durability of neutralizing antibodies after natural infection, and the breadth of therapeutic neutralizing antibodies and vaccine countermeasures. In summary, our studies have quantitated differences in ACE2 receptor expression and SARS-CoV-2 infectivity in the nose (high) versus the peripheral lung (low). These studies should provide valuable reference data for future animal model development and expand the pool of tissues, e.g., nasal, for future study of disease pathogenesis and therapy. Although speculative, if the nasal cavity is the initial site mediating seeding of the lung via aspiration, these studies argue for the widespread use of masks to prevent aerosol, large droplet, and/or mechanical exposure to the nasal passages. Complementary therapeutic strategies that reduce viral titer in the nose early in the disease, e.g., nasal lavages, topical antivirals, or immune modulation, might be beneficial. Finally, our studies provide key reagents and strategies to identify type-specific and highly conserved neutralizing antibodies that can be assessed most easily in the nasal cavity as well as in the blood and lower airway secretions. Reference & Source information: https://www.sciencedirect.com/ Read More on :

A coronavirus vaccine being developed by Oxford University will enter human trials as early as this Thursday, according to the U.K.’s health secretary. The U.K. government will provide £20 million ($24 million) to the university’s team and a further £22.5 million to Imperial College, where scientists are also working on a vaccine. Scientists at Oxford have previously said the aim is to produce a million doses of the vaccine by September. Secretary of State for Health and Social Care Matt Hancock praised both teams for making “rapid progress” and said the U.K. will throw “everything we’ve got” at developing a vaccine. He also said the government would invest in manufacturing capabilities so that if either vaccine was successful it could be available for British people “as soon as humanly possible.” “We are going to back them to the hilt and give them every resource that they need to get the best possible chance of success as soon as possible. The upside of being the first country in the world to develop a successful vaccine is so huge that I am throwing everything at it,” Hancock said. Read: These 21 companies are working on coronavirus treatments or vaccines However, he insisted vaccine development was a “process of trial and error and trial again.” The Oxford University project, a collaboration between the university’s Jenner Institute and Oxford Vaccine Group, opened recruitment for the clinical trial — for healthy adults between 18 and 55 — at the end of March, having begun research on a vaccine against the coronavirus-borne disease COVID-19 in February. Trials will now begin as soon as this Thursday, the health secretary revealed in the government’s daily briefing on Tuesday. Praising the team, Hancock said reaching this stage in normal times would “take years.” Also: GSK, Sanofi to team up on COVID-19 vaccine Speaking at the end of March, Adrian Hill, director of Oxford University’s Jenner Institute, said: “The Oxford team had exceptional experience of a rapid vaccine response, such as to the Ebola outbreak in West Africa in 2014. This is an even greater challenge. “Vaccines are being designed from scratch and progressed at an unprecedented rate. The upcoming trial will be critical for assessing the feasibility of vaccination against COVID-19 and could lead to early deployment.” Reference & source information : https://www.marketwatch.com/ Readmore on : https://www.marketwatch.com/story/oxford-university-coronavirus-vaccine-to-begin-human-trials-on-thursday-as-uk-throws-everything-at-vital-breakthrough-2020-04-21

There is an urgent need for antiviral strategies to combat hundreds of human disease-causing viruses. Currently approved antiviral drugs treat fewer than ten viral infections. A majority of these drugs are direct-acting antivirals (DAAs) that target proteins encoded by individual viruses. As such, this approach provides a narrow spectrum of coverage and therefore cannot address the large clinical need. The high average cost (over two billion dollars) and long timeline (8–12 years) to develop a new drug (Tufts center for the Study of Drug Development, 2014), further limit the scalability of the DAA approach to drug development, particularly with respect to emerging viruses. Lastly, the inability to provide adequate global health protection and national security preparedness against newly emerging viruses and the emergence of viral resistance further challenge conventional DAAs. The host-targeted broad-spectrum antiviral strategy represents an attractive potential solution to overcome these limitations. Viruses are dependent on cellular proteins for each step of their life cycle. Targeting host proteins required by multiple viruses can thus provide a broad-spectrum coverage with a possible added benefit of a high genetic barrier to resistance. Moreover, a broad-spectrum therapeutic could be administered even before a viral threat has been accurately diagnosed, thereby increasing protection. Host kinase inhibitors represent one category of compounds with a great potential to be repurposed as broad-spectrum antivirals. Viruses hijack a large number of host kinases at distinct steps of their life cycle (Supekova et al., 2008; Li et al., 2009; Keating and Striker, 2012; Jiang et al., 2014). Some of these host kinases are broadly required and thus represent attractive targets for broad-spectrum therapy (Table 1 and Figure 1). These findings, combined with the development and approval of a large number of kinase inhibitors for the treatment of cancer (Gross et al., 2015) and inflammatory conditions (Ott and Adams, 2011) have sparked efforts aimed to determine the therapeutic potential of such drugs to combat viral infections. In this review, we summarize recent efforts to determine the therapeutic potential and biological rationale of repurposing already approved kinase inhibitors as antivirals. Summary and Perspectives While repurposing of approved drugs as host-targeted broad-spectrum antivirals offers several important advantages over development of new DAAs, it also raises concerns. One obvious concern when targeting host functions is toxicity. Nevertheless, the protective effect of sunitinib/erlotinib combinations in murine models of DENV and EBOV (Bekerman et al., 2017) suggests that for some drugs it may be feasible to find a therapeutic window where the drug level is sufficient to inhibit viral replication with minimal cellular toxicity. Shortening the duration of therapy from months or years required to treat cancer to several days sufficient to treat most acute viral infections should further limit toxicity. Emergence of viral resistance is another potential challenge of broad-spectrum antiviral drugs (de Wispelaere et al., 2013; Haqqani and Tilton, 2013). Nevertheless, targeting host kinases that are not under the genetic control of viruses is more likely to have a higher barrier to resistance than classical DAAs. Moreover, simultaneous inhibition of several kinases or pathways by the same drug or drug combination could increase the effectiveness while minimizing viral resistance, as previously shown in cancer (Knight et al., 2010). Indeed, while DENV overcame inhibition by a DAA with the emergence of a resistance mutation, it remained susceptible to sunitinib and erlotinib, supporting the higher genetic barrier of the host-targeted antiviral approach (Bekerman et al., 2017). Lastly, understanding the MOA is challenging since cellular kinase function in a complex network of interactions and their inhibitors are often not selective. For example, erlotinib's effect on HCV entry was first attributed solely to its effect on EGFR, its known cancer target (Lupberger et al., 2011; Diao et al., 2012). We later demonstrated that ectopic expression not only of EGFR, but also GAK, which is inhibited by erlotinib with a comparable potency to EGFR (Kd of 3.4 nM vs. 1 nM) (Karaman et al., 2008), reversed erlotinib's anti-HCV effect (Neveu et al., 2015). Similarly, the anti-DENV effect of dasatinib was attributed to the inhibition of SFKs, particularly Fyn (Chu and Yang, 2007) (de Wispelaere et al., 2013). Nevertheless, the finding that c-Abl, another dasatinib target, is essential for DENV infection (Clark et al., 2016) suggests that c-Abl inhibition likely represents yet another mechanism through which dasatinib mediates its antiviral activity. These examples underscore the importance of validating not only the antiviral targets but also the molecular targets underlying the antiviral effect of such inhibitors. In summary, these examples provide a proof-of-concept for the potential feasibility of repurposing of approved kinase inhibitors as host-targeted broad-spectrum antiviral therapies to combat viral infections. While not yet approved, compounds targeting other kinases, such as the phosphatidylinositol 4-kinase family and IκB kinase-α, have already demonstrated antiviral activity (Altan-Bonnet and Balla, 2012; Li et al., 2013), suggesting that the repertoire of kinase inhibitor classes available for repurposing is likely to grow. Such approaches may find utility in combination with other strategies being developed to combat viruses. Reference & Source information: https://www.genengnews.com/ Read More on: https://www.genengnews.com/insights/repurposing-of-kinase-inhibitors-as-broad-spectrum-antiviral-drugs/

we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins physically associated with each using affinity-purification mass spectrometry (AP-MS), identifying 332 high-confidence SARS-CoV-2-human protein-protein interactions (PPIs). Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (29 FDA-approved drugs, 12 drugs in clinical trials, and 28 preclinical compounds). Screening a subset of these in multiple viral assays identified two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the Sigma1 and Sigma2 receptors. Further studies of these host factor targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19. In this study, we have identified 332 high-confidence SARS-CoV-2-human PPIs connected to multiple biological processes, including protein trafficking, translation, transcription and ubiquitination regulation. Against these targets we found 69 ligands, including FDA approved drugs, compounds in clinical trials, and preclinical compounds. Antiviral tests in two different laboratories reveal two broad sets of active drugs and compounds; those impinging on translation, and those modulating Sigma1 and Sigma2 receptors. Within these sets are at least five targets and over ten different chemotypes, suggesting a rich landscape for optimization.In this study, we have identified 332 high-confidence SARS-CoV-2-human PPIs connected to multiple biological processes, including protein trafficking, translation, transcription and ubiquitination regulation. Against these targets we found 69 ligands, including FDA approved drugs, compounds in clinical trials, and preclinical compounds. Antiviral tests in two different laboratories reveal two broad sets of active drugs and compounds; those impinging on translation, and those modulating Sigma1 and Sigma2 receptors. Within these sets are at least five targets and over ten different chemotypes, suggesting a rich landscape for optimization. Our approach of host-directed intervention as an antiviral strategy overcomes problems associated with drug resistance and may also provide pan-viral therapies as we prepare for the next pandemic. Furthermore, the possibilities for co-therapies are expanded, for example with drugs directly targeting the virus, including remdesivir, and, as we demonstrate in this study, a rich set of repurposing opportunities are illuminated. More broadly, the pipeline described here represents a new approach for drug discovery not only for pan-viral strategies, but for many diseases, and illustrates the speed in which science can be moved forward using a multi-disciplinary and collaborative approach. Reference & source information: https://www.nature.com/ Read More on :