Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral infection has been associated with severe cardiovascular complications. However, the role of epitranscriptional modulation involved in SARS-CoV-2-infected myocarditis is still unclear. Ten-eleven translocation 2 (TET2), a methylcytosine dioxygenase, plays key roles in DNA demethylation during viral infection and host-virus interactions. Using human-induced-pluripotent-stem-cell-derived cardiomyocytes (hiPSC-CMs) as a platform, our data revealed the epitranscriptomic role of TET2 during SARS-CoV-2 infection. First, our RNA sequencing analysis revealed the alterations of the messenger-RNA-expression profiles of epitranscriptomic regulators, including TET2, in hiPSC-CMs during SARS-CoV-2 infection. Second, silencing TET2 markedly reduced both the messenger RNA and protein levels of the viral nucleocapsid (N) protein, leading to attenuated viral replication in infected hiPSC-CMs. Furthermore, RNA dot-blotting analysis revealed that TET2 knockdown suppressed the levels of 5-hydroxymethylcytosine in SARS-CoV-2-infected hiPSC-CMs. To further explore the therapeutic relevance of TET2 inhibition in suppressing SARS-CoV-2 infection, we screened and compared 3 structurally distinct TET2 enzymatic inhibitors: Bobcat339, TETi76, and TFMB-2HG. Among these, Bobcat339 demonstrated the most potent antiviral effect, markedly suppressing SARS-CoV-2 replication and N-protein expression. Molecular docking analysis revealed that Bobcat339 exhibited a high binding affinity for multiple viral targets, including nsp16, RdRp, and N protein, indicating a multitarget mechanism of action. In addition, our data demonstrated that treatment with Bobcat339 can suppress SARS-CoV-2 infectious activity and N-protein expression in infected hiPSC-CMs. Together, our findings highlight the regulatory role of TET2 in SARS-CoV-2 infection and identify Bobcat339 as a promising therapeutic compound. Understanding TET2-driven epitranscriptomics and the functions of TET-targeting inhibitors may provide a novel strategy for mitigating viral infection in SARS-CoV-2-induced cardiomyopathy.

SARS-CoV-2, the virus responsible for COVID-19, triggers the synthesis of full-length genomic RNA (gRNA) and subgenomic RNAs (sgRNAs) in host cells upon infection. Traditional PCR aimed at targeting gRNA to detect viral presence is insufficient. sgRNAs serve as novel markers for active viral replication. However, the utility of reverse transcription-quantitative PCR (RT-qPCR) assays targeting sgRNAs as indicators of active viral load and infectivity in rodent models has not been validated. We developed four RT-qPCR assays targeting the SARS-CoV-2 genes-ORF1ab, N, E, and E-sgRNA and two RT-qPCR assays for housekeeping genes Hamster G apdh, and Mouse Actb. We used serial dilutions to establish standard curves for quantification. These assays demonstrated high amplification efficiency (96%-97 %) and a strong correlation between the cycle threshold (Ct) values and logarithmic copy number of the genes (R2 = 0.9933-0.9996). Analyzing 102 residual rodent lung tissue samples, we compared the viral loads quantified using RT-qPCR assays with those determined by viral culture. A strong correlation emerged between the RT-qPCR assays' detection of positivity and the viral culture results. Notably, the quantification of viral loads using the E-sgRNA RT-qPCR assay correlated more closely with viral culture outcomes than with other targets (r = 0.93, p < 0.001). These results underscore the sgRNA RT-qPCR assay's potential for tracking actively replicating viruses in rodent models infected with SARS-CoV-2, offering a reliable alternative to traditional viral culture methods.

This article describes a minimal invasive surgical (MIS) technique for arthroscopic repair of medial patellofemoral ligament partial tear on patella dislocation with suture anchor. Patella dislocation usually complicated with medial patellofemoral ligament (MPFL) injury, which lead to lateral subluxation or dislocation. MPFL acts as an important knee stabilizer to prevent lateralized force on the patellofemoral joint. Currently, surgical management includes various kinds of open procedures for repairing or reconstructing ligament. We had developed a MIS technique for arthroscopic repair on two patients with partial MPFL tear and recurrent patella subluxation/dislocation episodes. The radiographic and clinical results of both patients revealed restoration of full activity without patella subluxation after 12 months’ follow-up. We believed that this MIS technique prevent soft tissue from stripping and restore patella stability with good satisfaction.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral infection has been associated with severe cardiovascular complications. However, the role of epitranscriptional modulation involved in SARS-CoV-2-infected myocarditis is still unclear. Ten-eleven translocation 2 (TET2), a methylcytosine dioxygenase, plays key roles in DNA demethylation during viral infection and host-virus interactions. Using human-induced-pluripotent-stem-cell-derived cardiomyocytes (hiPSC-CMs) as a platform, our data revealed the epitranscriptomic role of TET2 during SARS-CoV-2 infection. First, our RNA sequencing analysis revealed the alterations of the messenger-RNA-expression profiles of epitranscriptomic regulators, including TET2, in hiPSC-CMs during SARS-CoV-2 infection. Second, silencing TET2 markedly reduced both the messenger RNA and protein levels of the viral nucleocapsid (N) protein, leading to attenuated viral replication in infected hiPSC-CMs. Furthermore, RNA dot-blotting analysis revealed that TET2 knockdown suppressed the levels of 5-hydroxymethylcytosine in SARS-CoV-2-infected hiPSC-CMs. To further explore the therapeutic relevance of TET2 inhibition in suppressing SARS-CoV-2 infection, we screened and compared 3 structurally distinct TET2 enzymatic inhibitors: Bobcat339, TETi76, and TFMB-2HG. Among these, Bobcat339 demonstrated the most potent antiviral effect, markedly suppressing SARS-CoV-2 replication and N-protein expression. Molecular docking analysis revealed that Bobcat339 exhibited a high binding affinity for multiple viral targets, including nsp16, RdRp, and N protein, indicating a multitarget mechanism of action. In addition, our data demonstrated that treatment with Bobcat339 can suppress SARS-CoV-2 infectious activity and N-protein expression in infected hiPSC-CMs. Together, our findings highlight the regulatory role of TET2 in SARS-CoV-2 infection and identify Bobcat339 as a promising therapeutic compound. Understanding TET2-driven epitranscriptomics and the functions of TET-targeting inhibitors may provide a novel strategy for mitigating viral infection in SARS-CoV-2-induced cardiomyopathy.

The rapid mutation rate of SARS-CoV-2 highlights the urgent need for continuous drug development to enhance both efficacy and safety. BPR2-D2, an angular coumarin derivative, has previously shown notable anti-influenza activity and broad-spectrum inhibitory effects against RNA viruses. In this study, we found that BPR2-D2 exhibits potent antiviral activity against multiple SARS-CoV-2 variants, including several variants of concern, at nanomolar concentrations. Notably, BPR2-D2 effectively disrupted viral RNA and protein synthesis in infected cells while mitigating pro-inflammatory cytokines triggered by viral replication. Our investigation of SARS-CoV-2 RdRp activity employed in silico analyses, including molecular docking, dynamic simulations, and binding free energy calculations. BPR2-D2 demonstrated superior binding affinity to the RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 compared to remdesivir. Additionally, it exhibited an increased synergistic inhibitory activity against the viral enzyme when combined with remdesivir. Both cell-based and in vitro enzyme-based RdRp reporter assays validated BPR2-D2's capacity to inhibit SARS-CoV-2 RdRp activity. The potential synergistic interaction between BPR2-D2 and remdesivir was investigated using cell-based combination assays. The results revealed a synergistic effect in reducing SARS-CoV-2 RNA synthesis, consistent with the in silico analysis. Collectively, these findings suggest that BPR2-D2, a repurposed small-molecule compound, effectively inhibits SARS-CoV-2 by modulating its RdRp function. This positions BPR2-D2 as a promising novel antiviral agent, while also providing insights into the complex molecular mechanisms underlying viral replication.

This study introduced a novel antiviral approach by combining three substances with different antiviral mechanisms: N-(2-hydroxy)propyl-3-trimethylammoniumchitosan (HTC), silver nanoparticles (AgNPs), and oseltamivir. First, positively surface-charged AgNPs were prepared using an environmentally friendly method. The surfaces of these AgNPs were capped with cationic quaternary chitosan HTC. It exhibits a positive zeta potential with extraordinary stability in aqueous solutions and facilitates substantial and rapid cellular uptake including entry into the cell nucleus. HTC-AgNPs display broad-spectrum antiviral activity against three influenza A viruses (H5N1, H3N2, and H1N1) at biocompatible concentrations. When blended with oseltamivir, HTC-AgNPs enhances the antiviral activity from that of oseltamivir alone by at least 20 times. After 24 h of combined treatment, the inhibition efficiency against influenza A virus can attain up to 99.9 %. We anticipate that this combination could reduce the effective dose of Tamiflu by 10-fold when used in clinic, thus shortening recovery period and lowering the medication costs. Moreover, the synergistic effects of the three active substances would reduce the likelihood of the emergence of drug-resistant viral strains. This would, in turn, enhance the effectiveness and safety of this medication.

ABSTRACT Viral RNA-dependent RNA polymerase (RdRp), a highly conserved molecule in RNA viruses, has recently emerged as a promising drug target for broad-acting inhibitors. Through a Vero E6-based anti-cytopathic effect assay, we found that BPR3P0128, which incorporates a quinoline core similar to hydroxychloroquine, outperformed the adenosine analog remdesivir in inhibiting RdRp activity (EC 50 = 0.66 µM and 3 µM, respectively). BPR3P0128 demonstrated broad-spectrum activity against various severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern. When introduced after viral adsorption, BPR3P0128 significantly decreased SARS-CoV-2 replication; however, it did not affect the early entry stage, as evidenced by a time-of-drug-addition assay. This suggests that BPR3P0128’s primary action takes place during viral replication. We also found that BPR3P0128 effectively reduced the expression of proinflammatory cytokines in human lung epithelial Calu-3 cells infected with SARS-CoV-2. Molecular docking analysis showed that BPR3P0128 targets the RdRp channel, inhibiting substrate entry, which implies it operates differently—but complementary—with remdesivir. Utilizing an optimized cell-based minigenome RdRp reporter assay, we confirmed that BPR3P0128 exhibited potent inhibitory activity. However, an enzyme-based RdRp assay employing purified recombinant nsp12/nsp7/nsp8 failed to corroborate this inhibitory activity. This suggests that BPR3P0128 may inhibit activity by targeting host-related RdRp-associated factors. Moreover, we discovered that a combination of BPR3P0128 and remdesivir had a synergistic effect—a result likely due to both drugs interacting with separate domains of the RdRp. This novel synergy between the two drugs reinforces the potential clinical value of the BPR3P0128-remdesivir combination in combating various SARS-CoV-2 variants of concern.

In this study, an efficient synthetic strategy and potential route to obtain a photo-reactive silver-containing cytosine-functionalized polypropylene glycol polymer (Ag-Cy-PPG) was developed by combining a hydrophilic oligomeric polypropylene glycol (PPG) backbone with dual pH-sensitive/photo-reactive cytosine-silver-cytosine (Cy-Ag-Cy) linkages. The resulting photo-responsive Ag-Cy-PPG holds great promise as a multifunctional biomedical material that generates spherical-like nanogels in water; the nanogels exhibit high antibacterial activity and thus may significantly enhance the efficacy of antibacterial treatment. Due to the formation of photo-dimerized Cy-Ag-Cy cross-linkages after UV irradiation, Ag-Cy-PPG converts into water-soluble cross linked nanogels that possess a series of interesting chemical and physical properties, such as intense and stable fluorescence behavior, highly sensitive pH-responsive characteristics, on/off switchable phase transition behavior, and well-controlled release of silver ions (Ag+) in mildly acidic aqueous solution. Importantly, antibacterial tests clearly demonstrated that irradiated Ag-Cy-PPG nanogels exhibited strong antibacterial activity at low doses (MIC values of < 50 mu g/mL) against gram-positive and gram-negative bacterial pathogens, whereas non-irradiated Ag-Cy-PPG nanogels did not inhibit the viability of bacterial pathogens. These results indicate that irradiated Ag-Cy-PPG nanogels undergo a highly sensitive structural change in the bacterial microenvironment due to their relatively unstable pi-conjugated structures (compared to non-irradiated nanogels); this change re-sults in a rapid structural response that promotes intracellular release of Ag(+ )and induces potent antibacterial ability. Overall, this newly created metallo-supramolecular system may potentially provide an efficient route to dramatically enhance the therapeutic effectiveness of antibacterial treatments.

Background: Modifications of lipid metabolism were closely associated with the manifestations and prognosis of coronavirus disease of 2019 (COVID-19). Pre-existing metabolic conditions exacerbated the severity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection while modulations of aberrant lipid metabolisms alleviated the manifestations. To elucidate the underlying mechanisms, an experimental platform that reproduces human respiratory physiology is required. Methods: Here we generated induced pluripotent stem cell-derived airway organoids (iPSC-AOs) that resemble the human native airway. Single-cell sequencing (ScRNAseq) and microscopic examination verified the cellular heterogeneity and microstructures of iPSC-AOs, respectively. We subjected iPSC-AOs to SARS-CoV-2 infection and investigated the treatment effect of lipid modifiers statin drugs on viral pathogenesis, gene expression, and the intracellular trafficking of the SARS-CoV-2 entry receptor angiotensin-converting enzyme-2 (ACE-2). Results: In SARS-CoV-2-infected iPSC-AOs, immunofluorescence staining detected the SARS-CoV-2 spike (S) and nucleocapsid (N) proteins and bioinformatics analysis further showed the aberrant enrichment of lipid-associated pathways. In addition, SARS-CoV-2 hijacked the host RNA replication machinery and generated the new isoforms of a high-density lipoprotein constituent apolipoprotein A1 (APOA1) and the virus-scavenging protein deleted in malignant brain tumors 1 (DMBT1). Manipulating lipid homeostasis using cholesterol-lowering drugs (e.g. Statins) relocated the viral entry receptor angiotensin-converting enzyme-2 (ACE-2) and decreased N protein expression, leading to the reduction of SARS-CoV-2 entry and replication. The same lipid modifications suppressed the entry of luciferase-expressing SARS-CoV-2 pseudoviruses containing the S proteins derived from different SARS-CoV-2 variants, i.e. wild-type, alpha, delta, and omicron. Conclusions: Together, our data demonstrated that modifications of lipid pathways restrict SARS-CoV-2 propagation in the iPSC-AOs, which the inhibition is speculated through the translocation of ACE2 from the cell membrane to the cytosol. Considering the highly frequent mutation and generation of SARS-CoV-2 variants, targeting host metabolisms of cholesterol or other lipids may represent an alternative approach against SARS-CoV-2 infection.

The incidence of zoonotic diseases, such as coronavirus disease 2019 and Ebola virus disease, is increasing worldwide. However, drug and vaccine development for zoonotic diseases has been hampered because the experiments involving live viruses are limited to high-containment laboratories. The Ebola virus minigenome system enables researchers to study the Ebola virus under BSL-2 conditions. Here, we found that the addition of the nucleocapsid protein of human coronaviruses, such as severe acute respiratory syndrome coronavirus 2, can increase the ratio of green fluorescent protein-positive cells by 1.5-2 folds in the Ebola virus minigenome system. Further analysis showed that the nucleocapsid protein acts as an activator of the Ebola virus minigenome system. Here, we developed an EBOV MiniG Plus system based on the Ebola virus minigenome system by adding the SARS-CoV-2 nucleocapsid protein. By evaluating the antiviral effect of remdesivir and rupintrivir, we demonstrated that compared to that of the traditional Ebola virus minigenome system, significant concentration-dependent activity was observed in the EBOV MiniG Plus system. Taken together, these results demonstrate the utility of adding nucleocapsid protein to the Ebola virus minigenome system to create a powerful platform for screening antiviral drugs against the Ebola virus.

COVID-19 is now considered a multiorgan disease with a wide range of manifestations. There are increasing reports of persistent and long-term effects after acute COVID-19, but the long-term health consequences of COVID-19 are not fully understood.

Osteoarthritis (OA) is the most common joint disease characterized by degeneration of articular cartilage and causes severe joint pain, physical disability, and impaired quality of life. Recently, it was found that mitochondria not only act as a powerhouse of cells that provide energy for cellular metabolism, but are also involved in crucial pathways responsible for maintaining chondrocyte physiology. Therefore, a growing amount of evidence emphasizes that impairment of mitochondrial function is associated with OA pathogenesis; however, the exact mechanism is not well known. Moreover, the AMP-activated protein kinase (AMPK)–Sirtuin (SIRT) signaling pathway, long non-coding RNA (lncRNA), and microRNA (miRNA) are important for regulating the physiological and pathological processes of chondrocytes, indicating that these may be targets for OA treatment. In this review, we first focus on the importance of mitochondria metabolic dysregulation related to OA. Then, we show recent evidence on the AMPK-SIRT mediated pathway associated with OA pathogenesis and potential treatment options. Finally, we discuss current research into the effects of lncRNA and miRNA on OA progression or inhibition.

The emergence of severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) variants has altered the trajectory of the COVID‐19 pandemic and raised some uncertainty on the long‐term efficiency of vaccine strategy. The development of new therapeutics against a wide range of SARS‐CoV‐2 variants is imperative. We, here, have designed an inhalable siRNA, C6G25S, which covers 99.8% of current SARS‐CoV‐2 variants and is capable of inhibiting dominant strains, including Alpha, Delta, Gamma, and Epsilon, at picomolar ranges of IC50 in vitro. Moreover, C6G25S could completely inhibit the production of infectious virions in lungs by prophylactic treatment, and decrease 96.2% of virions by cotreatment in K18‐hACE2‐transgenic mice, accompanied by a significant prevention of virus‐associated extensive pulmonary alveolar damage, vascular thrombi, and immune cell infiltrations. Our data suggest that C6G25S provides an alternative and effective approach to combating the COVID‐19 pandemic.

On analyzing the results of cell-based assays, we have previously shown that perilla (Perilla frutescens) leaf extract (PLE), a food supplement and orally deliverable traditional Chinese medicine approved by the Taiwan Food and Drug Administration, effectively inhibits SARS-CoV-2 by directly targeting virions. PLE was also found to modulate virus-induced cytokine expression levels. In this study, we explored the anti-SARS-CoV-2 activity of PLE in a hamster model by examining viral loads and virus-induced immunopathology in lung tissues. Experimental animals were intranasally challenged with different SARS-CoV-2 doses. Jugular blood samples and lung tissue specimens were obtained in the acute disease stage (3-4 post-infection days). As expected, SARS-CoV-2 induced lung inflammation and hemorrhagic effusions in the alveoli and perivascular areas; additionally, it increased the expression of several immune markers of lung injury - including lung Ki67-positive cells, Iba-1-positive macrophages, and myeloperoxidase-positive neutrophils. Virus-induced lung alterations were significantly attenuated by orally administered PLE. In addition, pretreatment of hamsters with PLE significantly reduced viral loads and immune marker expression. A purified active fraction of PLE was found to confer higher antiviral protection. Notably, PLE prevented SARS-CoV-2-induced increase in serum markers of liver and kidney function as well as the decrease in serum high-density lipoprotein and total cholesterol levels in a dose-dependent fashion. Differently from lung pathology, monitoring of serum biomarkers in Syrian hamsters may allow a more humane assessment of the novel drugs with potential anti-SARS-CoV-2 activity. Our results expand prior research by confirming that PLE may exert an in vivo therapeutic activity against SARS-CoV-2 by attenuating viral loads and lung tissue inflammation, which may pave the way for future clinical applications.

Background:Drug repurposing is a fast and effective way to develop drugs for an emerging disease such as COVID-19. The main challenges of effective drug repurposing are the discoveries of the right therapeutic targets and the right drugs for combating the disease.Methods:Here, we present a systematic repurposing approach, combining Homopharma and hierarchal systems biology networks (HiSBiN), to predict 327 therapeutic targets and 21,233 drug-target interactions of 1,592 FDA drugs for COVID-19. Among these multi-target drugs, eight candidates (along with pimozide and valsartan) were tested and methotrexate was identified to affect 14 therapeutic targets suppressing SARS-CoV-2 entry, viral replication, and COVID-19 pathologies. Through the use of in vitro (EC50 = 0.4 μM) and in vivo models, we show that methotrexate is able to inhibit COVID-19 via multiple mechanisms.Results:Our in vitro studies illustrate that methotrexate can suppress SARS-CoV-2 entry and replication by targeting furin and DHFR of the host, respectively. Additionally, methotrexate inhibits all four SARS-CoV-2 variants of concern. In a Syrian hamster model for COVID-19, methotrexate reduced virus replication, inflammation in the infected lungs. By analysis of transcriptomic analysis of collected samples from hamster lung, we uncovered that neutrophil infiltration and the pathways of innate immune response, adaptive immune response and thrombosis are modulated in the treated animals.Conclusions:We demonstrate that this systematic repurposing approach is potentially useful to identify pharmaceutical targets, multi-target drugs and regulated pathways for a complex disease. Our findings indicate that methotrexate is established as a promising drug against SARS-CoV-2 variants and can be used to treat lung damage and inflammation in COVID-19, warranting future evaluation in clinical trials.

Osteoarthritis (OA) is one of the most common diseases leading to physical disability, with age being the main risk factor, and degeneration of articular cartilage is the main focus for the pathogenesis of OA. Autophagy is a crucial intracellular homeostasis system recycling flawed macromolecules and cellular organelles to sustain the metabolism of cells. Growing evidences have revealed that autophagy is chondroprotective by regulating apoptosis and repairing the function of damaged chondrocytes. Then, OA is related to autophagy depending on different stages and models. In this review, we discuss the character of autophagy in OA and the process of the autophagy pathway, which can be modulated by some drugs, key molecules and non-coding RNAs (microRNAs, long non-coding RNAs and circular RNAs). More in-depth investigations of autophagy are needed to find therapeutic targets or diagnostic biomarkers through in vitro and in vivo situations, making autophagy a more effective way for OA treatment in the future. The aim of this review is to introduce the concept of autophagy and make readers realize its impact on OA. The database we searched in is PubMed and we used the keywords listed below to find appropriate article resources.

(Background) The coronavirus disease 2019 (COVID-19) that is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) carries high infectivity and mortality. Efficient intervention strategies are urgently needed. Avian immunoglobulin Y (IgY) showed efficacy against viral infection whereas the in vivo efficacy remains unclear. (Methods) We immunized laying hens with S1, S1 receptor-binding domain (S1-RBD), or S2 subunits of the SARS-CoV-2 spike (S) protein. After immunization, IgYs were collected and extracted from the egg yolks. The neutralization potential of IgYs was examined by the plaque reduction neutralization test (PRNT). The bioutility of IgYs was examined in Syrian hamsters in vivo. (Results) IgYs exhibited typical banding patterns in SDS-PAGE and Western blot and were immunoreactive against S1, S1-RBD, and S2 subunits. The plaque reduction neutralization test (PRNT) showed that all purified IgYs potently neutralized different SARS-CoV-2 strains in vitro. In Syrian hamsters, the combination of IgYs for S1-RBD and S2 subunits administered before or after SARS-CoV-2 infection effectively restored body weight loss and reduced intrapulmonary lesions and the amount of immunoreactive N protein-positive cells, which were caused by SARS-CoV-2 infection. (Conclusions) Collectively, IgYs specific for S protein subunits effectively neutralized SARS-CoV-2 in vitro and in vivo and may serve as prophylactic or therapeutic antibodies in the prevention or treatment of COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic with high infectivity and mortality has caused severe social and economic impacts worldwide. Growing reports of COVID-19 patients with multi-organ damage indicated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) may also disturb the cardiovascular system. Herein, we used human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iCMs) as the in vitro platform to examine the consequence of SARS-CoV2 infection on iCMs. Differentiated iCMs expressed the primary SARS-CoV2 receptor angiotensin-converting enzyme-II (ACE2) and the transmembrane protease serine type 2 (TMPRSS2) receptor suggesting the susceptibility of iCMs to SARS-CoV2. Following the infection of iCMs with SARS-CoV2, the viral nucleocapsid (N) protein was detected in the host cells, demonstrating the successful infection. Bioinformatics analysis revealed that the SARS-CoV2 infection upregulates several inflammation-related genes, including the proinflammatory cytokine tumor necrosis factor-α (TNF-α). The pretreatment of iCMs with TNF-α for 24 h, significantly increased the expression of ACE2 and TMPRSS2, SASR-CoV2 entry receptors. The TNF-α pretreatment enhanced the entry of GFP-expressing SARS-CoV2 pseudovirus into iCMs, and the neutralization of TNF-α ameliorated the TNF-α-enhanced viral entry. Collectively, SARS-CoV2 elevated TNF-α expression, which in turn enhanced the SARS-CoV2 viral entry. Our findings suggest that, TNF-α may participate in the cytokine storm and aggravate the myocardial damage in COVID-19 patients.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes severe “flu-like” symptoms that can progress to acute respiratory distress syndrome (ARDS), pneumonia, renal failure, and death. From the therapeutic perspective, 3-chymotrypsin-like protein (3CLpro) is a plausible target for direct-acting antiviral agents because of its indispensable role in viral replication. The flavonoid ugonin J (UJ) has been reported to have antioxidative and anti-inflammatory activities. However, the potential of UJ as an antiviral agent remains unexplored. In this study, we investigated the therapeutic activity of UJ against SARS-CoV-2 infection. Importantly, UJ has a distinct inhibitory activity against SARS-CoV-2 3CLpro, compared to luteolin, kaempferol, and isokaempferide. Specifically, UJ blocks the active site of SARS-CoV-2 3CLpro by forming hydrogen bonding and van der Waals interactions with H163, M165 and E166, G143 and C145, Q189, and P168 in subsites S1, S1′, S2, and S4, respectively. In addition, UJ forms strong, stable interactions with core pharmacophore anchors of SARS-CoV-2 3CLpro in a computational model. UJ shows consistent anti-inflammatory activity in inflamed human alveolar basal epithelial A549 cells. Furthermore, UJ has a 50% cytotoxic concentration (CC 50 ) and a 50% effective concentration (EC 50) values of about 783 and 2.38 µM, respectively, with a selectivity index (SI) value of 329, in SARS-CoV-2-infected Vero E6 cells. Taken together, UJ is a direct-acting antiviral that obstructs the activity of a fundamental protease of SARS-CoV-2, offering the therapeutic potential for SARS-CoV-2 infection.