Cyclosporin A Reveals Potent Antiviral Effects in Preclinical Models of SARS-CoV-2 Infection

Effect of cyclosporin A on respiratory viral replication in fully differentiated ex vivo human airway epithelia

Cyclosporin A (CsA), an immunosuppressive drug used in transplant recipients, inhibits graft rejection by binding to cyclophilins and competitively inhibiting calcineurin. While concerns about respiratory infections in immunosuppressed patients exist, contradictory data emerged during the COVID-19 pandemic, prompting investigations into CsA's impact on viral infections. This study explores CsA's antiviral effects on SARS-CoV-2 Omicron BA.1, Delta variants, and human parainfluenza virus 3 (HPIV3) using an ex vivo model of human airway epithelium (HAE). CsA exhibited a dose-dependent antiviral effect against the SARS-CoV-2 Delta variant, reducing viral load over 10 days. However, no significant impact was observed against SARS-CoV-2 Omicron or HPIV3, indicating a virus-specific effect. At high concentrations, CsA was associated with an increase of IL-8 and a decrease of IFNλ expression in infected and noninfected HAE. This study highlights the complexity of CsA's antiviral mechanisms, more likely involving intricate inflammatory pathways and interactions with specific viral proteins. The research provides novel insights into CsA's effects on respiratory viruses, emphasizing the need for understanding drug-virus interactions in optimizing therapeutic approaches for transplant recipients and advancing knowledge on immunosuppressive treatments' implications on respiratory viral infections. Limitations include the model's inability to assess T lymphocyte activation, suggesting the necessity for further comprehensive studies to decipher the intricate dynamics of immunosuppressive treatments on respiratory viral infections.

Time-course cross-species transcriptomics reveals conserved hepatotoxicity pathways induced by repeated administration of cyclosporine A

Cyclosporine A (CsA) has shown efficacy against immunity-related diseases despite its toxicity in various organs, including the liver, emphasizing the need to elucidate its underlying hepatotoxicity mechanism. This study aimed to capture the alterations in genome-wide expression over time and the subsequent perturbations of corresponding pathways across species. Six data from humans, mice, and rats, including animal liver tissue, human liver microtissues, and two liver cell lines exposed to CsA toxic dose, were used. The microtissue exposed to CsA for 10 d was analyzed to obtain dynamically differentially expressed genes (DEGs). Single-time points data at 1, 3, 5, 7, and 28 d of different species were used to provide additional evidence. Using liver microtissue-based longitudinal design, DEGs that were consistently up- or down-regulated over time were captured, and the well-known mechanism involved in CsA toxicity was elucidated. Thirty DEGs that consistently changed in longitudinal data were also altered in 28-d rat in-house data with concordant expression. Some genes (e.g. TUBB2A, PLIN2, APOB) showed good concordance with identified DEGs in 1-d and 7-d mouse data. Pathway analysis revealed up-regulations of protein processing, asparagine N-linked glycosylation, and cargo concentration in the endoplasmic reticulum. Furthermore, the down-regulations of pathways related to biological oxidations and metabolite and lipid metabolism were elucidated. These pathways were also enriched in single-time-point data and conserved across species, implying their biological significance and generalizability. Overall, the human organoids-based longitudinal design coupled with cross-species validation provides temporal molecular change tracking, aiding mechanistic elucidation and biologically relevant biomarker discovery.

Cyclosporine A-induced systemic metabolic perturbations in rats: A comprehensive metabolome analysis

A better understanding of cyclosporine A (CsA)-induced nephro- and hepatotoxicity at the molecular level is necessary for safe and effective use. Utilizing a sophisticated study design, this study explored metabolic alterations after long-term CsA treatment in vivo. Rats were exposed to CsA with 4, 10, and 25 mg/kg for 4 weeks and then sacrificed to obtain liver, kidney, urine, and serum for untargeted metabolomics analysis. Differential network analysis was conducted to explore the biological relevance of metabolites significantly altered by toxicity-induced disturbance. Dose-dependent toxicity was observed in all biospecimens. The toxic effects were characterized by alterations of metabolites related to energy metabolism and cellular membrane composition, which could lead to the cholestasis-induced accumulation of bile acids in the tissues. The unfavorable impacts were also demonstrated in the serum and urine. Intriguingly, phenylacetylglycine was increased in the kidney, urine, and serum treated with high doses versus controls. Differential correlation network analysis revealed the strong correlations of deoxycytidine and guanosine with other metabolites in the network, which highlighted the influence of repeated CsA exposure on DNA synthesis. Overall, prolonged CsA administration had system-level dose-dependent effects on the metabolome in treated rats, suggesting the need for careful usage and dose adjustment.

Nsp1 facilitates SARS-CoV-2 replication through calcineurin-NFAT signaling

SARS-CoV-2, the causative agent of COVID-19, has been intensely studied in search of effective antiviral treatments. The immunosuppressant cyclosporine A (CsA) has been suggested to be a pan-coronavirus inhibitor, yet its underlying mechanism remained largely unknown. Here, we found that non-structural protein 1 (Nsp1) of SARS-CoV-2 usurped CsA-suppressed nuclear factor of activated T cells (NFAT) signaling to drive the expression of cellular DEAD-box helicase 5 (DDX5), which facilitates viral replication. Nsp1 interacted with calcineurin A (CnA) to displace the regulatory protein regulator of calcineurin 3 (RCAN3) of CnA for NFAT activation. The influence of NFAT activation on SARS-CoV-2 replication was also validated by using the Nsp1-deficient mutant virus. Calcineurin inhibitors, such as CsA and VIVIT, inhibited SARS-CoV-2 replication and exhibited synergistic antiviral effects when used in combination with nirmatrelvir. Our study delineated the molecular mechanism of CsA-mediated inhibition of SARS-CoV-2 replication and the anti-SARS-CoV-2 action of calcineurin inhibitors.

IMPORTANCE

Cyclosporine A (CsA), commonly used to inhibit immune responses, is also known to have anti-SARS-CoV-2 activity, but its mode of action remains elusive. Here, we provide a model to explain how CsA antagonizes SARS-CoV-2 through three critical proteins: DDX5, NFAT1, and Nsp1. DDX5 is a cellular facilitator of SARS-CoV-2 replication, and NFAT1 controls the production of DDX5. Nsp1 is a viral protein absent from the mature viral particle and capable of activating the function of NFAT1 and DDX5. CsA and similar agents suppress Nsp1, NFAT1, and DDX5 to exert their anti-SARS-CoV-2 activity either alone or in combination with Paxlovid.

Preparing for the next viral threat with broad-spectrum antivirals

There is a large global unmet need for the development of countermeasures to combat hundreds of viruses known to cause human disease and for the establishment of a therapeutic portfolio for future pandemic preparedness. Most approved antiviral therapeutics target proteins encoded by a single virus, providing a narrow spectrum of coverage. This, combined with the slow pace and high cost of drug development, limits the scalability of this direct-acting antiviral (DAA) approach. Here, we summarize progress and challenges in the development of broad-spectrum antivirals that target either viral elements (proteins, genome structures, and lipid envelopes) or cellular proviral factors co-opted by multiple viruses via newly discovered compounds or repurposing of approved drugs. These strategies offer new means for developing therapeutics against both existing and emerging viral threats that complement DAAs.

Repurposing Drugs for the Treatment of COVID-19 and Its Cardiovascular Manifestations

COVID-19 is an infectious disease caused by SARS-CoV-2 leading to the ongoing global pandemic. Infected patients developed a range of respiratory symptoms, including respiratory failure, as well as other extrapulmonary complications. Multiple comorbidities, including hypertension, diabetes, cardiovascular diseases, and chronic kidney diseases, are associated with the severity and increased mortality of COVID-19. SARS-CoV-2 infection also causes a range of cardiovascular complications, including myocarditis, myocardial injury, heart failure, arrhythmias, acute coronary syndrome, and venous thromboembolism. Although a variety of methods have been developed and many clinical trials have been launched for drug repositioning for COVID-19, treatments that consider cardiovascular manifestations and cardiovascular disease comorbidities specifically are limited. In this review, we summarize recent advances in drug repositioning for COVID-19, including experimental drug repositioning, high-throughput drug screening, omics data-based, and network medicine-based computational drug repositioning, with particular attention on those drug treatments that consider cardiovascular manifestations of COVID-19. We discuss prospective opportunities and potential methods for repurposing drugs to treat cardiovascular complications of COVID-19.

Effects of immunophilin inhibitors and non-immunosuppressive analogs on coronavirus replication in human infection models

Rationale

Human coronaviruses (HCoVs) seriously affect human health by causing respiratory diseases ranging from common colds to severe acute respiratory diseases. Immunophilins, including peptidyl-prolyl isomerases of the FK506-binding protein (FKBP) and the cyclophilin family, are promising targets for pharmaceutical inhibition of coronavirus replication, but cell-type specific effects have not been elucidated. FKBPs and cyclophilins bind the immunosuppressive drugs FK506 and cyclosporine A (CsA), respectively.

Methods

Primary human bronchial epithelial cells (phBECs) were treated with CsA, Alisporivir (ALV), FK506, and FK506-derived non-immunosuppressive analogs and infected with HCoV-229E. RNA and protein were assessed by RT-qPCR and immunoblot analysis. Treatment with the same compounds was performed in hepatoma cells (Huh-7.5) infected with HCoV-229E expressing Renilla luciferase (HCoV-229E-RLuc) and the kidney cell line HEK293 transfected with a SARS-CoV-1 replicon expressing Renilla luciferase (SARS-CoV-1-RLuc), followed by quantification of luminescence as a measure of viral replication.

Results

Both CsA and ALV robustly inhibited viral replication in all models; both compounds decreased HCoV-229E RNA in phBECs and reduced luminescence in HCoV-229E-RLuc-infected Huh7.5 and SARS-CoV-1-RLuc replicon-transfected HEK293. In contrast, FK506 showed inconsistent and less pronounced effects in phBECs while strongly affecting coronavirus replication in Huh-7.5 and HEK293. Two non-immunosuppressive FK506 analogs had no antiviral effect in any infection model.

Conclusion

The immunophilin inhibitors CsA and ALV display robust anti-coronaviral properties in multiple infection models, including phBECs, reflecting a primary site of HCoV infection. In contrast, FK506 displayed cell-type specific effects, strongly affecting CoV replication in Huh7.5 and HEK293, but inconsistently and less pronounced in phBECs.

COVID-19-specific transcriptomic signature detectable in blood across multiple cohorts

The coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is spreading across the world despite vast global vaccination efforts. Consequently, many studies have looked for potential human host factors and immune mechanisms associated with the disease. However, most studies have focused on comparing COVID-19 patients to healthy controls, while fewer have elucidated the specific host factors distinguishing COVID-19 from other infections. To discover genes specifically related to COVID-19, we reanalyzed transcriptome data from nine independent cohort studies, covering multiple infections, including COVID-19, influenza, seasonal coronaviruses, and bacterial pneumonia. The identified COVID-19-specific signature consisted of 149 genes, involving many signals previously associated with the disease, such as induction of a strong immunoglobulin response and hemostasis, as well as dysregulation of cell cycle-related processes. Additionally, potential new gene candidates related to COVID-19 were discovered. To facilitate exploration of the signature with respect to disease severity, disease progression, and different cell types, we also offer an online tool for easy visualization of the selected genes across multiple datasets at both bulk and single-cell levels.