Large Screening Identifies ACE2 Positively Correlates With NF-κB Signaling Activity and Targeting NF-κB Signaling Drugs Suppress ACE2 Levels

SARS-CoV-2 Modulation of HIV Latency Reversal in a Myeloid Cell Line: Direct and Bystander Effects

Coronavirus disease 2019 (COVID-19) might impact disease progression in people living with HIV (PLWH), including those on effective combination antiretroviral therapy (cART). These individuals often experience chronic conditions characterized by proviral latency or low-level viral replication in CD4+ memory T cells and tissue macrophages. Pro-inflammatory cytokines, such as TNF-α, IL-1β, IL-6, and IFN-γ, can reactivate provirus expression in both primary cells and cell lines. These cytokines are often elevated in individuals infected with SARS-CoV-2, the virus causing COVID-19. However, it is still unknown whether SARS-CoV-2 can modulate HIV reactivation in infected cells. Here, we report that exposure of the chronically HIV-1-infected myeloid cell line U1 to two different SARS-CoV-2 viral isolates (ancestral and BA.5) reversed its latent state after 24 h. We also observed that SARS-CoV-2 exposure of human primary monocyte-derived macrophages (MDM) initially drove their polarization towards an M1 phenotype, which shifted towards M2 over time. This effect was associated with soluble factors released during the initial M1 polarization phase that reactivated HIV production in U1 cells, like MDM stimulated with the TLR agonist resiquimod. Our study suggests that SARS-CoV-2-induced systemic inflammation and interaction with macrophages could influence proviral HIV-1 latency in myeloid cells in PLWH.

ACE2 expression and spike S1 protein-mediated immune responses in oral mucosal cells

OBJECTIVES

ACE2, known as a host receptor involved with SARS-CoV-2 infection, binds to viral spike proteins for host cell entry. However, details regarding its induction and function in oral mucosal cells remain unknown.

MATERIALS AND METHODS

We examined ACE2 expression and its induction by transfected mimic nucleotides and pro-inflammatory cytokines in oral keratinocytes (RT7) and fibroblasts (GT1). Subsequently, the effects of viral spike S1 protein via ACE2 on CXCL10 expression induced by pro-inflammatory cytokines in both cells were examined.

RESULTS

ACE2 was constitutively expressed in RT7 and GT1. Transfected Poly(I:C) and Poly(dA:dT) increased ACE2 expression in those cells, while knockdown of RIG-I decreased ACE2 expression induced by those transfected ds nucleotides. IFN-γ and TNF-α enhanced transfected ds nucleotides-induced ACE2 expression in RT7 but not GT1. S1 protein alone did not affect CXCL10 expression in either cell type, whereas it enhanced IFN-β-induced CXCL10 in both, while immune responses of IFN-γ- and TNF-α-induced CXCL10 enhanced by S1 protein were different between RT7 and GT1. Finally, knockdown of ACE2 decreased cytokines and S1 protein mediated-CXCL10 levels in both cells.

CONCLUSIONS

ACE2 in oral mucosal cells may contribute to development of infection and inflammation in cooperation with pro-inflammatory cytokines following SARS-CoV-2 invasion.

Inhibition of porcine deltacoronavirus entry and replication by Cepharanthine

Porcine deltacoronavirus (PDCoV) is an emerging swine enteropathogenic coronavirus (CoV) that mainly causes acute diarrhea/vomiting, dehydration, and mortality in piglets, possessing economic losses and public health concerns. However, there are currently no proven effective antiviral agents against PDCoV. Cepharanthine (CEP) is a naturally occurring alkaloid used as a traditional remedy for radiation-induced symptoms, but its underlying mechanism of CEP against PDCoV has remained elusive. The aim of this study was to investigate the anti-PDCoV effects and mechanisms of CEP in LLC-PK1 cells. The results showed that the antiviral activity of CEP was based on direct action on cells, preventing the virus from attaching to host cells and virus replication. Importantly, Surface Plasmon Resonance (SPR) results showed that CEP has a moderate affinity to PDCoV receptor, porcine aminopeptidase N (pAPN) protein. AutoDock predicted that CEP can form hydrogen bonds with amino acid residues (R740, N783, and R790) in the binding regions of PDCoV and pAPN. In addition, RT-PCR results showed that CEP treatment could significantly reduce the transcription of ZBP1, cytokine (IL-1β and IFN-α) and chemokine genes (CCL-2, CCL-4, CCL-5, CXCL-2, CXCL-8, and CXCL-10) induced by PDCoV. Western blot analysis revealed that CEP could inhibit viral replication by inducing autophagy. In conclusion, our results suggest that the anti-PDCoV activity of CEP is not only relies on competing the virus binding with pAPN, but also affects the proliferation of the virus in vitro by downregulating the excessive immune response caused by the virus and inducing autophagy. CEP emerges as a promising candidate for potential anti-PDCoV therapeutic development.

Dissecting the molecular mechanism of cepharanthine against COVID-19, based on a network pharmacology strategy combined with RNA-sequencing analysis, molecular docking, and molecular dynamics simulation

OBJECTIVES

Recently, it has been reported that cepharanthine (CEP) is highly likely to be an agent against Coronavirus disease 2019 (COVID-19). In the present study, a network pharmacology-based approach combined with RNA-sequencing (RNA-seq), molecular docking, and molecular dynamics (MD) simulation was performed to determine hub targets and potential pharmacological mechanism of CEP against COVID-19.

METHODS

Targets of CEP were retrieved from public databases. COVID-19-related targets were acquired from databases and RNA-seq datasets GSE157103 and GSE155249. The potential targets of CEP and COVID-19 were then validated by GSE158050. Hub targets and signaling pathways were acquired through bioinformatics analysis, including protein-protein interaction (PPI) network analysis and enrichment analysis. Subsequently, molecular docking was carried out to predict the combination of CEP with hub targets. Lastly, MD simulation was conducted to further verify the findings.

RESULTS

A total of 700 proteins were identified as CEP-COVID-19-related targets. After the validation by GSE158050, 97 validated targets were retained. Enrichment results indicated that CEP acts on COVID-19 through multiple pathways, multiple targets, and overall cooperation. Specifically, PI3K-Akt signaling pathway is the most important pathway. Based on PPI network analysis, 9 central hub genes were obtained (ACE2, STAT1, SRC, PIK3R1, HIF1A, ESR1, ERBB2, CDC42, and BCL2L1). Molecular docking suggested that the combination between CEP and 9 central hub genes is extremely strong. Noteworthy, ACE2, considered the most important gene in CEP against COVID-19, binds to CEP most stably, which was further validated by MD simulation.

CONCLUSION

Our study comprehensively illustrated the potential targets and underlying molecular mechanism of CEP against COVID-19, which further provided the theoretical basis for exploring the potential protective mechanism of CEP against COVID-19.

A New Butyrate Releaser Exerts a Protective Action against SARS-CoV-2 Infection in Human Intestine

Butyrate is a major gut microbiome metabolite that regulates several defense mechanisms against infectious diseases. Alterations in the gut microbiome, leading to reduced butyrate production, have been reported in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. A new butyrate releaser, useful for all the known applications of butyrate, presenting physiochemical characteristics suitable for easy oral administration, (N-(1-carbamoyl-2-phenyl-ethyl) butyramide (FBA), has been recently developed. We investigated the protective action of FBA against SARS-CoV-2 infection in the human small intestine and enterocytes. Relevant aspects of SARS-CoV-2 infection were assessed: infectivity, host functional receptor angiotensin-converting enzyme-2 (ACE2), transmembrane protease serine 2 (TMPRSS2), neuropilin-1 (NRP1), pro-inflammatory cytokines expression, genes involved in the antiviral response and the activation of Nf-kB nuclear factor (erythroid-derived 2-like) 2 (Nfr2) pathways. We found that FBA positively modulates the crucial aspects of the infection in small intestinal biopsies and human enterocytes, reducing the expression of ACE2, TMPRSS2 and NRP1, pro-inflammatory cytokines interleukin (IL)-15, monocyte chemoattractant protein-1 (MCP-1) and TNF-α, and regulating several genes involved in antiviral pathways. FBA was also able to reduce the number of SARS-CoV-2-infected cells, and ACE2, TMPRSS2 and NRP1 expression. Lastly, through the inhibition of Nf-kB and the up-regulation of Nfr2, it was also able to reduce the expression of pro-inflammatory cytokines IL-15, MCP-1 and TNF-α in human enterocytes. The new butyrate releaser, FBA, exerts a preventive action against SARS-CoV-2 infection. It could be considered as an innovative strategy to limit COVID-19.