Ribavirin shows antiviral activity against SARS-CoV-2 and downregulates the activity of TMPRSS2 and the expression of ACE2 in vitro.

Ribavirin is a guanosine analog with broad-spectrum antiviral activity against RNA viruses. Based on this, we aimed to show the anti-SARS-CoV-2 activity of this drug molecule via in vitro, in silico, and molecular techniques. Ribavirin showed antiviral activity in Vero E6 cells following SARS-CoV-2 infection, whereas the drug itself did not show any toxic effect over the concentration range tested. In silico analysis suggested that ribavirin has a broad-spectrum impact on SARS-CoV-2, acting at different viral proteins. According to the detailed molecular techniques, ribavirin was shown to decrease the expression of TMPRSS2 at both mRNA and protein levels 48 h after treatment. The suppressive effect of ribavirin in ACE2 protein expression was shown to be dependent on cell types. Finally, proteolytic activity assays showed that ribavirin also showed an inhibitory effect on the TMPRSS2 enzyme. Based on these results, we hypothesized that ribavirin may inhibit the expression of TMPRSS2 by modulating the formation of inhibitory G-quadruplex structures at the TMPRSS2 promoter. As a conclusion, ribavirin is a potential antiviral drug for the treatment against SARS-CoV-2, and it interferes with the effects of TMPRSS2 and ACE2 expression.

Paraoxonase 1 (PON1) promoter (-107T/C) and coding region (192Q/R and 55L/M) genetic variations in pseudoexfoliation syndrome and pseudoexfoliative glaucoma risk.

PURPOSE: Pseudoexfoliation syndrome (PEX) is characterized by the accumulation of microscopic extracellular material in the anterior chamber of the eye and can lead to the development of pseudoexfoliative glaucoma (PEG) in some patients. The pathogenesis of PEX is not fully understood, and there are no objective biomarkers for its early diagnosis. Recent research has indicated that oxidative stress and inflammation might play a role in the pathophysiology of the production of pseudoexfoliation material. Therefore, in the present study, we aimed to analyze the possible association between three genetic variants of paraoxonase 1 (PON1), a well-recognized antioxidant and anti-inflammatory enzyme, and PEX/PEG. METHODS: The study population consisted of patients with PEX (n = 150), patients with PEG (n = 150), and control subjects (n = 150). PON1 -107T/C, 192Q/R, and 55L/M genotypes were determined using PCR followed by restriction fragment length polymorphism analysis. The correlation between these genetic alterations and clinical visual characteristics was also investigated. RESULTS: The minor allele frequencies and genotype distributions of PON1 did not differ significantly between the PEG, PEX, and control groups. Moreover, PON1 genotypes did not significantly influence visual clinical parameters in stratification analysis. On the other hand, in correlation analysis, pattern standard deviation was significantly correlated with the -107T/C genotypes in PEX group. In addition, intraocular pressure was correlated with the 55L/M genotypes and mean deviation was correlated with the -107T/C genotypes in the control group. Furthermore, intraocular pressure was significantly inversely correlated with sex (r =  - 0.116, P = 0.011) in the overall study group. Logistic regression analysis showed that having a PON1 -107TC or CC genotype is significantly associated with PEX (OR = 1.909, P = 0.020). CONCLUSIONS: This study, for the first time, analyzed the relationship between PON1 genetic variants, clinical visual parameters, and PEX/PEG. The results indicated a possible role for the PON1 promoter variant in PEX.