SARS-CoV2-mediated suppression of NRF2-signaling reveals potent antiviral and anti-inflammatory activity of 4-octyl-itaconate and dimethyl fumarate.

Antiviral strategies to inhibit Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) and the pathogenic consequences of COVID-19 are urgently required. Here, we demonstrate that the NRF2 antioxidant gene expression pathway is suppressed in biopsies obtained from COVID-19 patients. Further, we uncover that NRF2 agonists 4-octyl-itaconate (4-OI) and the clinically approved dimethyl fumarate (DMF) induce a cellular antiviral program that potently inhibits replication of SARS-CoV2 across cell lines. The inhibitory effect of 4-OI and DMF extends to the replication of several other pathogenic viruses including Herpes Simplex Virus-1 and-2, Vaccinia virus, and Zika virus through a type I interferon (IFN)-independent mechanism. In addition, 4-OI and DMF limit host inflammatory responses to SARS-CoV2 infection associated with airway COVID-19 pathology. In conclusion, NRF2 agonists 4-OI and DMF induce a distinct IFN-independent antiviral program that is broadly effective in limiting virus replication and in suppressing the pro-inflammatory responses of human pathogenic viruses, including SARS-CoV2.

Author Correction: SARS-CoV2-mediated suppression of NRF2-signaling reveals potent antiviral and anti-inflammatory activity of 4-octyl-itaconate and dimethyl fumarate.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

STING agonists enable antiviral cross-talk between human cells and confer protection against genital herpes in mice.

In recent years, there has been an increasing interest in immunomodulatory therapy as a means to treat various conditions, including infectious diseases. For instance, Toll-like receptor (TLR) agonists have been evaluated for treatment of genital herpes. However, although the TLR7 agonist imiquimod was shown to have antiviral activity in individual patients, no significant effects were observed in clinical trials, and the compound also exhibited significant side effects, including local inflammation. Cytosolic DNA is detected by the enzyme cyclic GMP-AMP (2'3'-cGAMP) synthase (cGAS) to stimulate antiviral pathways, mainly through induction of type I interferon (IFN)s. cGAS is activated upon DNA binding to produce the cyclic dinucleotide (CDN) 2'3'-cGAMP, which in turn binds and activates the adaptor protein Stimulator of interferon genes (STING), thus triggering type I IFN expression. In contrast to TLRs, STING is expressed broadly, including in epithelial cells. Here we report that natural and non-natural STING agonists strongly induce type I IFNs in human cells and in mice in vivo, without stimulating significant inflammatory gene expression. Systemic treatment with 2'3'-cGAMP reduced genital herpes simplex virus (HSV) 2 replication and improved the clinical outcome of infection. More importantly, local application of CDNs at the genital epithelial surface gave rise to local IFN activity, but only limited systemic responses, and this treatment conferred total protection against disease in both immunocompetent and immunocompromised mice. In direct comparison between CDNs and TLR agonists, only CDNs acted directly on epithelial cells, hence allowing a more rapid and IFN-focused immune response in the vaginal epithelium. Thus, specific activation of the STING pathway in the vagina evokes induction of the IFN system but limited inflammatory responses to allow control of HSV2 infections in vivo.

miRNA profiling identifies deregulated miRNAs associated with osteosarcoma development and time to metastasis in two large cohorts.

Osteosarcoma (OS) is an aggressive bone tumor primarily affecting children and adolescents. The etiology of OS is not fully understood. Thus, there is a great need to obtain a better understanding of OS development and progression. Alterations in miRNA expression contribute to the required molecular alterations for neoplastic initiation and progression. This study is the first to investigate miRNA expression in OS in a large discovery and validation cohort comprising a total of 101 OS samples. We established the signature of altered miRNA expression in OS by profiling the expression level of 752 miRNAs in 23 OS samples using sensitive LNA-enhanced qPCR assays. The identified miRNA expression changes were correlated with gene expression in the same samples. Furthermore, miRNA expression changes were validated in a second independent cohort consisting of 78 OS samples. Analysis of 752 miRNAs in the discovery cohort led to the identification of 33 deregulated miRNAs in OS. Twenty-nine miRNAs were validated with statistical significance in the second cohort comprising 78 OS samples. miRNA/mRNA targets were determined, and 361 genes with an inverse expression of the target miRNA were identified. Both the miRNAs and the identified target genes were associated with multiple pathways related to cancer as well as bone cell biology, thereby correlating the deregulated miRNAs with OS tumorigenesis. An analysis of the prognostic value of the 29 miRNAs identified miR-221/miR-222 to be significantly associated with time to metastasis in both cohorts. This study contributes to a more profound understanding of OS tumorigenesis, by substantiating the importance of miRNA deregulation. We have identified and validated 29 deregulated miRNAs in the - to our knowledge - largest discovery and validation cohorts used so far for miRNA analyses in OS. Two of the miRNAs showed a promising potential as prognostic biomarkers for the aggressiveness of OS.

The association between miR-34 dysregulation and distant metastases formation in lung adenocarcinoma.

Lung cancer has the highest mortality rate amongst human cancers and the majority of deaths can be attributed to metastatic spread. The miR-34 family includes three tumor suppressive miRs: miR-34a, miR-34b and miR-34c. miR-34 downregulation is a frequent observation in human malignancies and is often attributed to hypermethylation of the miR-34a and miR-34b/c promoters. Here, the potential association between aberrant miR-34 expression and promoter methylation and distant metastases formation in lung adenocarcinoma (LAC) is investigated. The expression levels of miR-34a, miR-34b and miR-34c, as well as the methylation status of the miR-34a and miR-34b/c promoters were determined in a LAC patient cohort comprising 26 non-metastasizing and 26 metastasizing primary LACs, as well as 24 paired distant metastases and 25 tumor-adjacent normal lung samples using RT-qPCR and Methylation-Sensitive High Resolution Melting (MS-HRM) analysis. No difference in expression was observed for miR-34a when comparing metastasizing and non-metastasizing LACs (p=0.793). For both miR-34b and miR-34c, a significantly lower expression level was determined in metastasizing LACs compared to non-metastasizing LACs (p=0.0005 and p=0.002) with similarly decreased expression levels observed in the paired distant metastases. Hypermethylation was detected in 35/51 LACs compared to 0/25 tumor-adjacent normal lungs for the miR-34a promoter (p<0.0001). Similarly, 18/51 LACs compared to 1/25 tumor-adjacent normal lungs showed hypermethylation of the miR-34b/c promoter (p=0.003). No difference in methylation was observed between metastasizing and non-metastasizing LACs for neither the miR-34a (p=0.832) nor the miR-34b/c (p=0.900) promoter. In conclusion, miR-34a and miR-34b/c promoter hypermethylation is a frequent event in LAC occurring in 68.7% and 35.3% of tested cases (n=51), respectively. Low miR-34b and miR-34c expression was associated with distant metastases formation in LAC. These changes can be targeted as novel biomarkers in LAC.