Statins and Hepatitis C Virus Infection: An Old Therapy With New Scope

25-Hydroxycholesterol inhibits Hantavirus infection by reprogramming cholesterol metabolism

Hantavirus causes two types of acute diseases: hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome. It is a major health concern due to its high mortality and lack of effective treatment. Type I interferon treatment has been suggested to be effective against hantavirus when treated in advance. Interferons induce multiple interferon-stimulated genes (ISGs), whose products are highly effective at resisting and controlling viruses. A product of ISGs, the enzyme cholesterol 25-hydroxylase (CH25H), catalyzes the oxidation of cholesterol to 25-hydroxycholesterol (25HC). 25HC can inhibit multiple enveloped-virus infections, but the mechanism is largely unknown, and whether 25HC plays an important role in regulating hantavirus remains unexplored. In this study, we show that Hantaan virus (HTNV), the prototype hantavirus, induced CH25H gene in infected cells. Overexpression of CH25H and treatment with 25HC, inhibited HTNV infection, possibly by lowering 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMG-CoA reductase, HMGCR), which inhibits cholesterol biosynthesis. In addition, cholesterol-lowering drugs such as HMGCR-targeting statins have potent hantavirus inhibitory effects. Our results indicate that 25HC and some statins are potential antiviral agents effective against hantavirus infections. This study provides evidence that targeting cholesterol metabolism is promising in developing specific hantavirus antivirals and indicates the possibility of repurposing FDA-approved cholesterol-lowering drug, statins for treating hantavirus infection.

Cholesterol: A friend to viruses

Cholesterol is a key life-sustaining molecule which regulates membrane fluidity and serves as a signaling mediator. Cholesterol homeostasis is closely related to various pathological conditions including tumor, obesity, atherosclerosis, Alzheimer's disease and viral infection. Viral infection disrupts host cholesterol homeostasis, facilitating their own survival. Meanwhile, the host cells strive to reduce cholesterol accessibility to limit viral infection. This review focuses on the regulation of cholesterol metabolism and the role of cholesterol in viral infection, specifically providing an overview of cholesterol as a friend to promote viral entry, replication, assembly, release and immune evasion, which might inspire valuable thinking for pathogenesis and intervention of viral infection.

Simvastatin Improves Benign Prostatic Hyperplasia: Role of Peroxisome-Proliferator-Activated Receptor-γ and Classic WNT/β-Catenin Pathway

Benign prostatic hyperplasia (BPH) is a common disease in elderly men with an uncertain etiology and mechanistic basis. Metabolic syndrome (MetS) is also a very common illness and is closely related to BPH. Simvastatin (SV) is one of the widely used statins for MetS. Peroxisome-proliferator-activated receptor gamma (PPARγ), crosstalking with the WNT/β-catenin pathway, plays important roles in MetS. Our current study aimed to examine SV-PPARγ-WNT/β-catenin signaling in the development of BPH. Human prostate tissues and cell lines plus a BPH rat model were utilized. Immunohistochemical, immunofluorescence, hematoxylin and eosin (H&E) and Masson's trichrome staining, construction of a tissue microarray (TMA), ELISA, CCK-8 assay, qRT-PCR, flow cytometry, and Western blotting were also performed. PPARγ was expressed in both prostate stroma and epithelial compartments and downregulated in BPH tissues. Furthermore, SV dose-dependently triggered cell apoptosis and cell cycle arrest at the G0/G1 phase and attenuated tissue fibrosis and the epithelial-mesenchymal transition (EMT) process both in vitro and in vivo. SV also upregulated the PPARγ pathway, whose antagonist could reverse SV produced in the aforementioned biological process. Additionally, crosstalk between PPARγ and WNT/β-catenin signaling was demonstrated. Finally, correlation analysis with our TMA containing 104 BPH specimens showed that PPARγ was negatively related with prostate volume (PV) and free prostate-specific antigen (fPSA) and positively correlated with maximum urinary flow rate (Qmax). WNT-1 and β-catenin were positively related with International Prostate Symptom Score (IPSS) and nocturia, respectively. Our novel data demonstrate that SV could modulate cell proliferation, apoptosis, tissue fibrosis, and the EMT process in the prostate through crosstalk between PPARγ and WNT/β-catenin pathways.

Prospects for the use of statins in antiviral therapy

Inhibitors of hydroxymethylglutaryl-CoA reductase, in addition to suppressing cholesterol synthesis, have an antiviral effect. Clinical studies have shown antiviral efficacy of statins against COVID-19, HCV, HBV, RSV, HIV, influenza viruses. The ability of statins to inhibit influenza viruses, COVID-19, RSV, HIV, as well as Ebola, Zika, Dengue, Coxsackie, rotaviruses, ADV, HDV, HHV was experimentally confirmed. Statins can also enhance the effects of antiviral drugs, making them more effective in treating infections. Therefore, the use of statins in the complex therapy of viral infections is promising. In addition, the role of influenza viruses, T-cell leukemia and herpesviruses, HIV, HBV, HCV, HPV in the development of atherosclerosis has been identified, so the use of statins in complex treatment is also necessary to correct endothelial dysfunction that occurs under the influence of viruses. Since the activity of retroelements that are evolutionarily related to exogenous viruses increases with aging, it has been suggested that retrotransposons can also be targets for statins. This is evidenced by a change in the expression of non-coding RNAs under the action of statins, since the key sources of non-coding RNAs are retroelements. This property may be an additional factor in the prescription of statins to increase life expectancy, in addition to the prevention and treatment of atherosclerosis, since pathological activation of retroelements are the causes of aging. Viruses, like retroelements, are involved in the pathogenesis of malignant neoplasms, in the treatment of which statins have shown their effectiveness and the ability to enhance the effect of anticancer drugs, overcoming chemoresistance (similar to the potentiation of antiviral drugs). One of the mechanisms of this activity of statins may be their effect on retroelements and viruses.

Simvastatin re-sensitizes hepatocellular carcinoma cells to sorafenib by inhibiting HIF-1α/PPAR-γ/PKM2-mediated glycolysis

BACKGROUND

Hepatocellular carcinoma (HCC) is a common primary malignant tumor which usually progresses to an advanced stage because of late diagnosis. Sorafenib (Sora) is a first line medicine for advanced stage HCC; however, it has been faced with enormous resistance. Simvastatin (Sim) is a cholesterol-lowering drug and has been reported to inhibit tumor growth. The present study aims to determine whether Sora and Sim co-treatment can improve Sora resistance in HCC.

METHODS

The HCC cell line LM3 and an established Sora-resistant LM3 cell line (LM3-SR) were used to study the relationship between Sora resistance and aerobic glycolysis. Cell proliferation, apoptosis and glycolysis levels were analyzed by western blotting, flow cytometry analysis and biomedical tests. A xenograft model was also used to examine the effect of Sim in vivo. Detailed mechanistic studies were also undertaken by the use of activators and inhibitors, and lentivirus transfections.

RESULTS

Our results demonstrated that the resistance to Sora was associated with enhanced aerobic glycolysis levels. Furthermore, LM3-SR cells were more sensitive to Sim than LM3 cells, suggesting that combined treatment with both Sora and Sim could enhance the sensitivity of LM3-SR cells to Sora. This finding may be due to the suppression of the HIF-1α/PPAR-γ/PKM2 axis.

CONCLUSIONS

Simvastatin can inhibit the HIF-1α/PPAR-γ/PKM2 axis, by suppressing PKM2-mediated glycolysis, resulting in decreased proliferation and increased apoptosis in HCC cells, and re-sensitizing HCC cells to Sora.

Limiting Cholesterol Biosynthetic Flux Spontaneously Engages Type I IFN Signaling

Cellular lipid requirements are achieved through a combination of biosynthesis and import programs. Using isotope tracer analysis, we show that type I interferon (IFN) signaling shifts the balance of these programs by decreasing synthesis and increasing import of cholesterol and long chain fatty acids. Genetically enforcing this metabolic shift in macrophages is sufficient to render mice resistant to viral challenge, demonstrating the importance of reprogramming the balance of these two metabolic pathways in vivo. Unexpectedly, mechanistic studies reveal that limiting flux through the cholesterol biosynthetic pathway spontaneously engages a type I IFN response in a STING-dependent manner. The upregulation of type I IFNs was traced to a decrease in the pool size of synthesized cholesterol and could be inhibited by replenishing cells with free cholesterol. Taken together, these studies delineate a metabolic-inflammatory circuit that links perturbations in cholesterol biosynthesis with activation of innate immunity.

Effect of addition of statins to antiviral therapy in hepatitis C virus-infected persons: Results from ERCHIVES

3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been variably noted to affect hepatitis C virus (HCV) treatment response, fibrosis progression, and hepatocellular carcinoma (HCC) incidence, with some having a more potent effect than others. We sought to determine the impact of adding statins to antiviral therapy upon sustained virological response (SVR) rates, fibrosis progression, and HCC development among HCV-infected persons using the Electronically Retrieved Cohort of HCV Infected Veterans (ERCHIVES), an established, longitudinal, national cohort of HCV-infected veterans. Within ERCHIVES, we identified those who received HCV treatment and a follow-up of >24 months after treatment completion. We excluded those with human immunodeficiency virus coinfection, hepatitis B surface antigen positivity, cirrhosis, and HCC at baseline. Our main outcomes were liver fibrosis progression measured by FIB-4 scores, SVR rates, and incident HCC (iHCC). Among 7,248 eligible subjects, 46% received statin therapy. Statin use was significantly associated with attaining SVR (39.2% vs. 33.3%; P < 0.01), decreased cirrhosis development (17.3% vs. 25.2%; P < 0.001), and decreased iHCC (1.2% vs. 2.6%; P < 0.01). Statins remained significantly associated with increased odds of SVR (odds ratio = 1.44; 95% confidence interval [CI] = 1.29, 1.61), but lower fibrosis progression rate, lower risk of progression to cirrhosis (hazard ratio [HR] = 0.56; 95% CI = -0.50, 0.63), and of incident HCC (HR = 0.51; 95% CI = 0.34, 0.76) after adjusting for other relevant clinical factors.

CONCLUSIONS

Statin use was associated with improved virological response (VR) rates to antiviral therapy and decreased progression of liver fibrosis and incidence of HCC among a large cohort of HCV-positive Veterans. These data support the use of statins in patients with HCV.