Biology subjects

Luna, J. M.

Publications and source records attributed to Luna, J. M..

4 recordsLinked to original sources

bioRxiv2020

Human hepatocyte PNPLA3 148M exacerbates rapid non-alcoholic steatohepatitis development in chimeric mice

Advanced non-alcoholic fatty liver disease (NAFLD) is a rapidly emerging global health problem associated with pre-disposing genetic polymorphisms, most strikingly an isoleucine to methionine substitution in patatin-like phospholipase domain-containing protein 3 (PNPLA3-I148M). Here, we study how human hepatocytes with PNPLA3 148I and 148M variants engrafted in the livers of chimeric mice respond to a hypercaloric Western-style diet. As early as 4 weeks, mice developed dyslipidemia, impaired glucose tolerance, and steatohepatitis selectively in the human graft, followed by pericellular fibrosis after 8 weeks of hypercaloric feeding. The PNPLA3 148M variant, either from a homozygous 148M human donor or overexpressed in a homozygous 148I donor background, caused widespread microvesicular steatosis and even more severe steatohepatitis. We conclude that PNPLA3 148M in human hepatocytes exacerbates NAFLD. These models will facilitate mechanistic studies into human genetic variants associated with advanced fatty liver diseases.

pathology↗

bioRxiv2020

Genome-scale identification of SARS-CoV-2 and pan-coronavirus host factor networks

The COVID-19 pandemic has claimed the lives of more than one million people worldwide. The causative agent, SARS-CoV-2, is a member of the Coronaviridae family, which are viruses that cause respiratory infections of varying severity. The cellular host factors and pathways co-opted by SARS-CoV-2 and other coronaviruses in the execution of their life cycles remain ill-defined. To develop an extensive compendium of host factors required for infection by SARS-CoV-2 and three seasonal coronaviruses (HCoV-OC43, HCoV-NL63, and HCoV-229E), we performed parallel genome-scale CRISPR knockout screens. These screens uncovered multiple host factors and pathways with pan-coronavirus and virus-specific functional roles, including major dependency on glycosaminoglycan biosynthesis, SREBP signaling, and glycosylphosphatidylinositol biosynthesis, as well as an unexpected requirement for several poorly characterized proteins. We identified an absolute requirement for the VTT-domain containing protein TMEM41B for infection by SARS-CoV-2 and all other coronaviruses. This human Coronaviridae host factor compendium represents a rich resource to develop new therapeutic strategies for acute COVID-19 and potential future coronavirus spillover events. HIGHLIGHTSGenome-wide CRISPR screens for SARS-CoV-2, HCoV-OC43, HCoV-NL63, and HCoV-229E coronavirus host factors. Parallel genome-wide CRISPR screening uncovered host factors and pathways with pan-coronavirus and virus-specific functional roles. Coronaviruses co-opt multiple biological pathways, including glycosaminoglycan biosynthesis, SREBP signaling, and glycosylphosphatidylinositol biosynthesis and anchoring, among others. TMEM41B - a poorly understood factor with roles in autophagy and lipid mobilization - is a critical pan-coronavirus host factor.

microbiology↗

bioRxiv2020

Functional interrogation of a SARS-CoV-2 host protein interactome identifies unique and shared coronavirus host factors

The ongoing SARS-CoV-2 pandemic has devastated the global economy and claimed nearly one million lives, presenting an urgent global health crisis. To identify host factors required for infection by SARS-CoV-2 and seasonal coronaviruses, we designed a focused high-coverage CRISPR-Cas9 library targeting 332 members of a recently published SARS-CoV-2 protein interactome. We leveraged the compact nature of this library to systematically screen four related coronaviruses (HCoV-229E, HCoV-NL63, HCoV-OC43 and SARS-CoV-2) at two physiologically relevant temperatures (33 {degrees}C and 37 {degrees}C), allowing us to probe this interactome at a much higher resolution relative to genome scale studies. This approach yielded several new insights, including unexpected virus and temperature specific differences in Rab GTPase requirements and GPI anchor biosynthesis, as well as identification of multiple pan-coronavirus factors involved in cholesterol homeostasis. This coronavirus essentiality catalog could inform ongoing drug development efforts aimed at intercepting and treating COVID-19, and help prepare for future coronavirus outbreaks. HIGHLIGHTSFocused CRISPR screens targeting host factors in the SARS-CoV-2 interactome were performed for SARS-CoV-2, HCoV-229E, HCoV-NL63, and HCoV-OC43 coronaviruses. Focused interactome CRISPR screens achieve higher resolution compared to genome-wide screens, leading to the identification of critical factors missed by the latter. Parallel CRISPR screens against multiple coronaviruses uncover host factors and pathways with pan-coronavirus and virus-specific functional roles. The number of host proteins that interact with a viral bait protein is not proportional to the number of functional interactors. Novel SARS-CoV-2 host factors are expressed in relevant cell types in the human airway.

microbiology↗

bioRxiv2020

Lung type II alveolar epithelial cells collaborate with CCR2+ inflammatory monocytes in host defense against an acute vaccinia infection in the lungs

The pulmonary immune system consists of a network of tissue-resident cells as well as immune cells that are recruited to the lungs during infection and/or inflammation. How the two immune components cross-talk during an acute viral infection is not well understood. Intranasal infection of mice with vaccinia virus causes lethal pneumonia and systemic dissemination. Here we report that vaccinia host range protein C7 is a critical virulence factor. Vaccinia virus with deletion of C7 (VACV{Delta}C7L) is non-pathogenic in wild-type C57BL/6J mice, but it gains virulence in mice lacking STAT2, or IFNAR1, or MDA5/STING. We provide evidence that lung type II alveolar epithelial cells (AECs) provide first-line of defense against VACV{Delta}C7L infection by inducing IFN-{beta} and IFN-stimulated genes via the activation of the MDA5 and STING-mediated nucleic acid-sensing pathways. This leads to recruitment of CCR2+ inflammatory monocytes into the lungs to fight against viral dissemination.

immunology↗