The Role of Coronavirus Spike Protein in Inducing Optic Neuritis in Mice: Parallels to the SARS-CoV-2 Virus.

BACKGROUND: Optic neuritis (ON), one of the clinical manifestations of the human neurological disease multiple sclerosis (MS), was also reported in patients with COVID-19 infection, highlighting one potential neurological manifestation of SARS-CoV-2. However, the mechanism of ON in these patients is poorly understood. EVIDENCE ACQUISITION: Insight may be gained by studying the neurotropic mouse hepatitis virus (MHV-A59), a ß-coronavirus that belongs to the same family as SARS-CoV-2. RESULTS: Mouse hepatitis virus-A59, or its isogenic spike protein recombinant strains, inoculation in mice provides an important experimental model to understand underpinning mechanisms of neuroinflammatory demyelination in association with acute stage optic nerve inflammation and chronic stage optic nerve demyelination concurrent with axonal loss. Spike is a surface protein that mediates viral binding and entry into host cells, as well as cell-cell fusion and viral spread. Studies have implicated spike-mediated mechanisms of virus-induced neuroinflammatory demyelination by comparing naturally occurring demyelinating (DM) and nondemyelinating (NDM) MHV strains. CONCLUSIONS: Here, we summarize findings in MHV-induced experimental ON and myelitis, using natural DM and NDM strains as well as engineered recombinant strains of MHV to understand the role of spike protein in inducing ON and demyelinating disease pathology. Potential parallels in human coronavirus-mediated ON and demyelination, and insight into potential therapeutic strategies, are discussed.

Regulatory role of endoplasmic reticulum resident chaperone protein ERp29 in anti-murine ß-coronavirus host cell response.

Gap junctional intercellular communication (GJIC) involving astrocytes is important for proper CNS homeostasis. As determined in our previous studies, trafficking of the predominant astrocyte GJ protein, Connexin43 (Cx43), is disrupted in response to infection with a neurotropic murine ß-coronavirus (MHV-A59). However, how host factors are involved in Cx43 trafficking and the infection response is not clear. Here, we show that Cx43 retention due to MHV-A59 infection was associated with increased ER stress and reduced expression of chaperone protein ERp29. Treatment of MHV-A59-infected astrocytes with the chemical chaperone 4-sodium phenylbutyrate increased ERp29 expression, rescued Cx43 transport to the cell surface, increased GJIC, and reduced ER stress. We obtained similar results using an astrocytoma cell line (delayed brain tumor) upon MHV-A59 infection. Critically, delayed brain tumor cells transfected to express exogenous ERp29 were less susceptible to MHV-A59 infection and showed increased Cx43-mediated GJIC. Treatment with Cx43 mimetic peptides inhibited GJIC and increased viral susceptibility, demonstrating a role for intercellular communication in reducing MHV-A59 infectivity. Taken together, these results support a therapeutically targetable ERp29-dependent mechanism where ß-coronavirus infectivity is modulated by reducing ER stress and rescuing Cx43 trafficking and function.

Prognostic utility of the ovarian cancer secretome: a systematic investigation.

BACKGROUND: Ovarian cancer is usually detected at an advanced stage with frequent recurrence. The recurrence-free survival and overall survival is influenced by the age at diagnosis, tumor stage and histological subtype. Nonetheless, quantifiable prognostic biomarkers are needed for early identification of the high-risk patients and for personalized medicine. Several studies link tumor-specific dysregulated expression of certain proteins with ovarian cancer prognosis. However, careful investigation of presence of these prognostically relevant proteins in ovarian cancer secretome is lacking. OBJECTIVE: To critically analyze the recent published data on prognostically relevant proteins for ovarian cancer and to carefully search how many of them are reported in the published ovarian cancer secretome datasets. DESIGN: A search for relevant studies in the past 2 years was conducted in PubMed and a comprehensive list of proteins associated with the ovarian cancer prognosis was prepared. These were cross-referred to the published ovarian cancer secretome profiles. The proteins identified in the secretome were further shortlisted based on a scoring strategy employing stringent criteria. RESULTS: A panel of seven promising secretory biomarkers associated with ovarian cancer prognosis is proposed. CONCLUSION: Scanning the ovarian cancer secretome datasets provides the opportunity to identify if tumor-specific biomarkers could be tested as secretory biomarkers. Detecting their levels in the body fluid would be more advantageous than evaluating the expression in the tissue, since it could be monitored multiple times over the course of the disease to have a better judgment of the prognosis and response to therapy.

Potential Immunomodulatory Properties of Biologically Active Components of Spices Against SARS-CoV-2 and Pan ß-Coronaviruses.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced COVID-19 has emerged as a defining global health crisis in current times. Data from the World Health Organization shows demographic variations in COVID-19 severity and lethality. Diet may play a significant role in providing beneficial host cell factors contributing to immunity against deadly SARS-CoV-2 pathogenesis. Spices are essential components of the diet that possess anti-inflammatory, antioxidant, and antiviral properties. Hyperinflammation, an aberrant systemic inflammation associated with pneumonia, acute respiratory failure, and multiorgan dysfunction, is a major clinical outcome in COVID-19. Knowing the beneficial properties of spices, we hypothesize that spice-derived bioactive components can modulate host immune responses to provide protective immunity in COVID-19. This study emphasizes that biologically active components of spices might alleviate the sustained pro-inflammatory condition by inhibiting the activity of tumor necrosis factor-alpha (TNF-α), interleukins (IL6, IL8), and chemokine (CCL2) known to be elevated in COVID-19. Spices may potentially prevent the tissue damage induced by oxidative stress and pro-inflammatory mediators during SARS-CoV-2 infection. The current study also highlights the effects of spices on the antioxidant pathways mediated by Nrf2 (nuclear factor erythroid 2-related factor 2) and Hmox1 (heme oxygenase 1) to restore oxidative homeostasis and protect from aberrant tissue damage. Taken together, the anti-inflammatory and antioxidant activities of bioactive components of spices may hold a promise to target the cellular pathways for developing antivirals against SARS-CoV-2 and pan ß-coronaviruses.