Impact of pre-existing SARS-CoV-2 reactive T cells in uninfected individuals on COVID-19 mortality in different countries (preprint)

Several recent studies identified SARS-CoV-2 reactive T cells in people without exposure to the virus. However, pathophysiological implications of these findings remain unknown. Here, the potential impact of pre-existing T cell reactivity against SARC-CoV-2 in uninfected individuals on markedly different COVID-19 mortality levels in different countries has been investigated. The inverse correlation is documented between the prevalence of pre-existing SARS-CoV-2 reactive T cells in people without exposure to the virus and COVID-19 mortality rates in different countries. In countries with similar levels of pre-existing SARS-CoV-2 cross-reactive T cells in uninfected individuals, differences in COVID-19 mortality appear linked with the extend and consistency of implementations of social measures designed to limit the transmission of SARS-CoV-2 (lockdown; physical distancing; mask wearing). Collectively, these observations support the model that the level of pre-existing SARS-CoV-2 reactive T cells is one of the important determinants of the innate herd immunity against COVID-19. Together with the consistent social measures directed to limit the virus spread, high levels of pre-existing SARS-CoV-2 reactive T cells appear significant determinants diminishing the COVID-19 mortality. Observations reported in this contribution should have significant impact on definitions of the herd immunity threshold required to effectively stop the pandemic in different countries across the globe.

Tripartite combination of potential pandemic mitigation agents: Vitamin D, Quercetin, and Estradiol manifest properties of candidate medicinal agents for mitigation of the severity of pandemic COVID-19 defined by genomics-guided tracing of SARS-CoV-2 targets in human cells. (preprint)

Genes required for SARS-CoV-2 entry into human cells, ACE2 and FURIN , were employed as baits to build genomics-guided molecular maps of up-stream regulatory elements, their expression and functions in human body, including pathophysiologically-relevant cell types. Repressors and activators of the ACE2 and FURIN genes were identified based on the analyses of gene silencing and overexpression experiments as well as relevant transgenic mouse models. Panels of repressors ( VDR; GATA5; SFTPC; HIF1a ) and activators ( HMGA2; INSIG1 ) were then employed to identify existing drugs manifesting gene expression signatures of the potential coronavirus infection mitigation agents. Using this strategy, Vitamin D and Quercetin have been identified as putative COVID-19 mitigation agents. Quercetin has been identified as one of top-scoring candidate therapeutics in the supercomputer SUMMIT drug-docking screen and Gene Set Enrichment Analyses (GSEA) of expression profiling experiments (EPEs), indicating that highly similar structurally Quercetin, Luteolin, and Eriodictyol could serve as scaffolds for development of efficient inhibitors of the SARS-CoV-2 infection. In agreement with this notion, Quercetin alters expression of 98 of 332 (30%) of human genes encoding protein targets of SARS-CoV-2, thus potentially interfering with functions of 23 of 27 (85%) of the SARS-CoV-2 viral proteins in human cells. Similarly, Vitamin D may interfere with functions of 19 of 27 (70%) of the SARS-CoV-2 proteins by altering expression of 84 of 332 (25%) of human genes encoding protein targets of SARS-CoV-2. Considering the potential effects of both Quercetin and Vitamin D, the inference could be made that functions of 25 of 27 (93%) of SARS-CoV-2 proteins in human cells may be altered. GSEA and EPEs identify multiple drugs, smoking, and many disease conditions that appear to act as putative coronavirus infection-promoting agents. Discordant patterns of Testosterone versus Estradiol impacts on SARS-CoV-2 targets suggest a plausible molecular explanation of the apparently higher male mortality during coronavirus pandemic. Estradiol, in contrast with Testosterone, affects expression of a majority of human genes (203 of 332; 61%) encoding SARS-CoV-2 targets, thus potentially interfering with functions of 26 of 27 SARS-CoV-2 viral proteins. A hypothetical tripartite combination consisting of Quercetin/Vitamin D/Estradiol may affect expression of 244 of 332 (73%) human genes encoding SARS-CoV-2 targets. Of major concern is the ACE2 and FURIN expression in many human cells and tissues, including immune cells, suggesting that SARS-CoV-2 coronavirus may infect a broad range of cellular targets in the human body. Infection of immune cells may cause immunosuppression, long-term persistence of the virus, and spread of the virus to secondary targets. Present analyses and numerous observational studies indicate that age-associated Vitamin D deficiency may contribute to high mortality of older adults and elderly. Immediate availability for targeted experimental and clinical interrogations of potential COVID-19 pandemic mitigation agents, namely Vitamin D and Quercetin, as well as of the highly selective (K i, 600 pm) intrinsically-specific FURIN inhibitor (a1-antitrypsin Portland (a1-PDX), is considered an encouraging factor. Observations reported in this contribution are intended to facilitate follow-up targeted experimental studies and, if warranted, randomized clinical trials to identify and validate therapeutically-viable interventions to combat the COVID-19 pandemic. Specifically, gene expression profiles of Vitamin D and Quercetin activities and their established safety records as over-the-counter medicinal substances strongly argue that they may represent viable candidates for further considerations of their potential utility as COVID-19 pandemic mitigation agents. In line with results of present analyses, a randomized interventional clinical trial entitled “Phase II Clinical Trial of Estradiol to Reduce Severity of COVID19 Infection in COVID19+ and Presumptive COVID19+ Patients” has been posted on ClinicalTrials.gov website (https://clinicaltrials.gov/ct2/show/NCT04359329 ) and two interventional randomized clinical trials evaluating effects of Vitamin D on prevention and treatment of COVID-19 were listed on ClinicalTrials.gov website (https://www.clinicaltrials.gov/ct2/show/NCT04334005 and https://clinicaltrials.gov/ct2/show/NCT04344041 ).

Genomics-guided molecular maps of coronavirus targets in human cells: a path toward the repurposing of existing drugs to mitigate the pandemic (preprint)

Human genes required for SARS-CoV-2 entry into human cells, ACE2 and FURIN, were employed as baits to build genomics-guided maps of up-stream regulatory elements, their expression and functions in human body, including pathophysiologically-relevant cell types. Genes acting as repressors and activators of the ACE2 and FURIN genes were identified based on the analyses of gene silencing and overexpression experiments as well as relevant transgenic mouse models. Panels of repressors (VDR; GATA5; SFTPC; HIF1a) and activators (HMGA2; INSIG1) were then employed to identify existing drugs that could be repurposed to mitigate the coronavirus infection. Present analyses identify Vitamin D and Quercetin as promising pandemic mitigation agents. Gene expression profiles of Vitamin D and Quercetin activities and their established safety records as over-the-counter medicinal substances suggest that they may represent viable candidates for further assessment and considerations of their potential as coronavirus pandemic mitigation agents. Notably, gene set enrichment analyses and expression profiling experiments identify multiple drugs, most notably testosterone, dexamethasone, and doxorubicin, smoking, and many disease conditions that appear to act as putative coronavirus infection-promoting agents. Discordant patterns of Testosterone versus Estradiol impacts on SCARS-CoV-2 targets suggest a plausible molecular explanation of the apparently higher male mortality during coronavirus pandemic.