Hussain, S.-R. A. | Search bioRxiv

bioRxiv2023

Neuregulin-1 protects against respiratory viral induced mortality

Respiratory viral infections due to RNA viruses such as respiratory syncytial virus (RSV) and influenza lead to significant morbidity and mortality. Using a natural rodent pathogen similar to RSV, Sendai virus (SeV), we found that mice made atopic with house dust mite before viral infection all survived a normally lethal SeV infection. Moreover, adoptive transfer of CD11c+ cells from atopic mice delayed viral mortality. Neuregulin-1 (NRG1) message was highly expressed in CD11c+ cells from atopic mice and atopic lungs and bronchoalveolar lavage fluid had elevated levels of NRG1 protein. Administration of NRG1 protected non-atopic mice from death and associated with reduced alveolar epithelium permeability. Utilizing an in vitro system of well-differentiated human bronchial epithelial cells and mouse tracheal epithelial cells NRG1 reduced RSV and SeV titers. Expression of genes that play a role in airway epithelium integrity and stability were altered by NRG1; potentially regulating viral induced dysregulation of the epithelia and suggesting NRG1 mediated maintenance of homeostasis. In conclusion, our studies demonstrate atopy induced NRG1 likely plays a novel role in survival from severe respiratory viral infections and may have therapeutic value to prevent mortality from these infections. SignificanceSevere respiratory viral infections are associated with significant mortality in infants and the elderly; however, allergic disease can protect from these outcomes. This study identified a protein called neuregulin-1 (NRG1), produced by cells of the immune system in allergic mice, that provides a survival advantage against respiratory viral infection. NRG1 pretreatment in non-atopic mice infected with a lethal dose of a rodent RNA virus (Sendai virus), similar to human respiratory syncytial virus, significantly reduced death. Further, NRG1 pretreatment reduced viral replication in human and mouse airway epithelial cell cultures. These studies signify a potential therapeutic role of NRG1 in modulating the severity of respiratory viral infections.

immunology↗

bioRxiv2020

Adapting CRISPR/Cas9 System for Targeting Mitochondrial Genome

Gene editing of the mitochondrial genome using CRISPR-Cas9 system is highly challenging mainly due to sub-efficient delivery of guide RNA and Cas9 enzyme complexes into mitochondria. In this study, we were able to perform gene editing in the mitochondrial DNA by appending NADH-ubiquinone oxidoreductase chain 4 (ND4) targeting guide RNA to a RNA transport derived stem loop element (RP-loop) and expressing the Cas9 enzyme with preceding mitochondrial localization sequence. Our results showed mitochondrial co-localization of RP-loop gRNA and a marked reduction of ND4 expression in the cells carrying a A11204G variant in their ND4 sequence coincidently decreasing the mtDNA levels. This proof-of-concept study suggests that stem loop element added sgRNA can be transported to the mitochondria and functionally interact with Cas9 to mediate sequence specific mtDNA cleavage. Using this novel approach to target the mtDNA, our results provide further evidence that CRISPR-Cas9 mediated gene editing might potentially be used to treat mtDNA related diseases.

molecular biology↗