Biology subjects

Yadav, K. K.

Publications and source records attributed to Yadav, K. K..

5 recordsLinked to original sources

bioRxiv2024

A porcine chronic hepatitis E virus (HEV) infection model exhibits HEV replication in male accessory reproductive glands and immune-mediated reproductive damage

Hepatitis E virus (HEV) is an expanding zoonotic viral disease threat. Although HEV causes acute viral hepatitis, it is increasingly being recognized as a systemic pathogen with detection and damage in extrahepatic tissues. The presence of HEV RNA in the semen of chronically infected human patients in the absence of viremia and fecal shedding and presence of HEV in the sperm head underscores the need to understand the interaction of HEV within the male reproduction system. Male accessory glands secrete biofluids necessary for sperm nourishment and to neutralize the acidity of the vagina. The role of male accessory glands in the dissemination and persistence of HEV infection have not been studied. Using an immunosuppressed pig model for chronic HEV infection, we demonstrate infectious HEV in mature sperm cells altering the sperm motility and morphology. HEV isolated from sperm cells remained infectious in human hepatoma cells. Spermatic fluid contained lower virus titers than the sperm cells from chronically infected pigs highlighting that the sperm cells themselves can associate with the virus. Evaluation of the male accessory glands demonstrated viral replication, infiltration of CD45 leukocytes, and apoptosis associated with HEV infection. A decrease in serum testosterone levels was evident in the HEV infected pigs. Even though a lower viral RNA titer was seen in serum and feces of chronically infected, immunosuppressed and ribavirin treated pigs, high viral RNA and infectious particles in sperm is a concern. Our findings necessitate further studies defining the mechanism of sperm cell invasion by HEV, length of HEV survival in sperm cells during chronic HEV infection, and risk of sexual transmission of HEV during both acute and chronic phases of infection. Author SummaryHepatitis E virus, a leading cause of acute viral hepatitis, causes both acute and chronic infection in humans. Recent advances within the HEV field have demonstrated extrahepatic diseases associated with HEV. More recent findings have revealed infectious HEV in the vagina, Sertoli cells, and ejaculate of humans, and sperm cells of pigs. We demonstrate that the male accessory sex glands may have a role in the persistence of HEV infection during chronic infections. We utilized an established immunosuppressed pig model and treated pigs with ribavirin to study the presence of virus in the sperm cells. We demonstrated high viral RNA loads and infectious particles associated with sperm cells. Our study further highlights the importance of the testis, as an immune privileged site, in the maintenance of chronic HEV infection. New studies to evaluate the mechanisms by which HEV associates with sperm cells, the length of HEV survival in sperm cell fractions, and consideration of the testes as a potential HEV reservoir are necessary.

microbiology↗

bioRxiv2023

Rat hepatitis E virus (HEV) cross-species infection and transmission in pigs

Rocahepevirus ratti, an emerging hepatitis E virus (HEV), has recently been found to be infectious to humans. Rats are a primary reservoir of the virus; thus, it is referred to as "rat HEV". Rats are often found on swine farms in close contact with pigs. Our goal was to determine whether swine may serve as a transmission host for rat HEV by characterizing an infectious cDNA clone of a zoonotic rat HEV, strain LCK-3110, in vitro and in vivo. RNA transcripts of LCK-3110 were constructed and assessed for their replicative capacity in cell culture and in gnotobiotic pigs. Fecal suspension from rat HEV-positive gnotobiotic pigs was inoculated into conventional pigs cohoused with naive pigs. Our results demonstrated that capped RNA transcripts of LCK-3110 rat HEV replicated in vitro and successfully infected conventional pigs that transmit the virus to cohoused animals. The infectious clone of rat HEV may afford an opportunity to study the genetic mechanisms of rat HEV cross-species infection and tissue tropism. Significance StatementNew zoonotic strains of Rocahepevirus ratti (rat HEV) have emerged infecting both immunocompetent and immunosuppressed people through unknown transmission sources. Pigs are a primary source of transmission for human HEV strains and could be serving a similar role for rat HEV transmission as rats are a common pest found on swine farms worldwide. Rats could be transmitting rat HEV to pigs which could then be transmitted to humans. Determining susceptibility of pigs to emerging zoonotic rat HEV strains can define potentially new transmission routes to inform public health policy and could provide pathology models for rat HEV disease.

microbiology↗

bioRxiv2019

Lecithin:Retinol Acyl Transferase (LRAT) inducesthe formation of lipid droplets

Lipid droplets are unique and nearly ubiquitous organelles that store neutral lipids in a hydrophobic core, surrounded by a monolayer of phospholipids. The primary neutral lipids are triacylglycerols and steryl esters. It is not known whether other classes of neutral lipids can form lipid droplets by themselves. Here we show that production of retinyl esters by lecithin:retinol acyl transferase (LRAT) in yeast cells, incapable of producing triacylglycerols and steryl esters, causes the formation of lipid droplets. By electron microscopy, these lipid droplets are morphologically indistinguishable from those in wild-type cells. In silico and in vitro experiments confirmed the propensity of retinyl esters to segregate from membranes and to form lipid droplets. The hydrophobic N-terminus of LRAT displays preferential interactions with retinyl esters in membranes and promotes the formation of large retinyl ester-containing lipid droplets in mammalian cells. Our combined data indicate that the molecular design of LRAT is optimally suited to allow the formation of characteristic large lipid droplets in retinyl ester-storing cells.

biochemistry↗

bioRxiv2019

Apolipoprotein L9 interacts with LC3/GABARAP and is a microtubule-associated protein with a widespread subcellular distribution

Mouse Apolipoprotein L9 is a 34-kDa phosphatidylethanolamine (PE)-binding protein. The gene is present only in mouse and rat genomes; hence it is taxonomically restricted. To understand why, it is essential to uncover details about its functions in cellular processes. Here we show that ApoL9 interacts with the proteins of the LC3 and GABARAP subfamilies, which are key players in macroautophagy. In amino-acid starved cells it preferentially interacts with lipidated LC3B, likely by binding to its PE moiety. On treatment with autophagy inhibitors bafilomycin A1 and chloroquine, ApoL9 is found near swollen mitochondria and on lysosomes/LAMP1-positive compartments. However, ApoL9 itself does not seem to be degraded as a result of autophagy, suggesting that it is not an autophagy cargo receptor. Deletions in a putative transmembrane region between amino acids 110 and 145 abolish PE-binding. In addition, ApoL9 can redistribute to stress granules, can homooligomerize, and is a microtubule-associated protein. In short, its distribution in the cell is quite widespread, suggesting that it could have functions at the intersection of membrane binding and reorganization, autophagy, cellular stress and intracellular lipid transport.\n\nSummary statementThis article is about how Apolipoprotein L9, a lipid-binding protein, has versatile properties and influences a variety of processes taking place inside an animal cell.

cell biology↗

bioRxiv2018

Epigenetic analysis identifies factors driving racial disparity in prostate cancer

Prostate cancer (PCa) is the second most leading cause of death in men worldwide. African American men (AA) represent more aggressive form of PCa as compared to Caucasian (CA) counterparts. Evidence suggests that genetic and other biological factors could account for the observed racial disparity. We analyzed the cancer genome atlas (TCGA) dataset (2015) for existing epigenetic variation in AA and CA prostate cancer patients, and carried out Reduced Representation Bisulphite Sequencing (RRBS) analysis to identify global methylation changes in AA and CA prostate cancer patients. The TCGA dataset analysis revealed that the epigenetic heterogeneity could be categorized into 4 classes, where AA associated primarily to methylation cluster 1 (p value 0.048), and CA associated to methylation cluster 3 (p value 0.000146). We identified enrichment of Wnt signaling genes in both AA and CA, however they were differentially activated in terms of canonical and non-canonical Wnt signaling pathway activation. This was further validated using the GenomeDx expression data. Our RRBS data also suggested distinct methylation patterns in AA compared to CA, and in part validated our TCGA findings. Survival analysis using the RRBS data suggested hypomethylated genes to be significantly associated with recurrence of prostate cancer in CA (p=6.07x10-6) as well as in AA (p=0.0077). Overall, the observed racial disparity in the molecular mechanism involved in the pathogenesis of prostate cancer suggests diverse heterogeneity that potentially could affect survival and should be considered during prognosis and treatment.

cancer biology↗