Acute murine cytomegalovirus infection boosts cell-type specific response and lipid metabolism changes in infant mice liver
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ABSTRACT: Human cytomegalovirus (HCMV) infection in infants cause severe diseases, such as neonatal hepatitis. However, the single-cell dimensional description of the immune cell alteration during the first virus exposure process in infants, remains poorly understood. The hepatocytes play an essential role in metabolic homeostasis and detoxification. The Concomitant Effects of CMV infection on liver lipid metabolism in infants are still unclear. Here, using single-cell RNA-sequencing, we found MCMV can infect most cell types of infant mice liver, changing the number of immune cells. MCMV infection increases proliferating CD8 effector T cells and a subset of Nos2+ monocytes, which may play important roles in the early anti-viral process. Furthermore, MCMV infection subvert the protein expression profile of lipid metabolism in hepatocytes. Overall, our data provide insights as to how the immune system response to MCMV infection during the early stage of infection, and the impact of infection on lipid metabolism in infant mice hepatocytes.
Project description:Human cytomegalovirus (HCMV) infection in infants cause severe diseasessuch as neonata hepatitis, However, the single-cell dimensiona description otthe immune cel alteration during the first virus exposure process in infantsremains poorly understood. The hepatocytes play an essential role in metabolichomeostasis and detoxification, The Concomitant Effects of CMV infection oriver lipid metabolism in infants are still unclear. Here, using single-cell RNAsequencing, we found MCMV can infect most cell types of infant mice liverchanging the number of immune cells, MCMV infection increases proliferatincsubset of Nos2+CD8 effectorcells and amonocytes,which may plalimportant roles in the early anti-viral process. Furthermore, MCMV infectiorsubvert the protein expression profile of lipid metabolism in hepatocytesOverall, our data provide insights as to how the immune system response toMCMY infection during the early stage of infection, and the impact of infectionon lipid metabolism in infant mice hepatocvtes.
Project description:Prenatal exposures such as infections and immunisation may influence infant responses. We had an opportunity to undertake an analysis of responses in infants within the context of a study investigating the effects of maternal mycobacterial exposures and infection on bacille Calmette-Guerin (BCG) vaccine-induced responses in Ugandan infants. Gene expression profiles for pathways associated with maternal LTBI and with maternal BCG scar were examined using samples collected at one (n=42) and six (n=51) weeks after BCG immunisation using microarray. Interferon and inflammation response pathways were up-regulated in infants of mothers with LTBI at six weeks, and in infants of mothers with a BCG scar at one and six weeks after BCG immunisation. Maternal BCG scar had a stronger association with infant responses than maternal LTBI, with an increased proinflammatory immune profile.
Project description:Respiratory syncytial virus (RSV) selectively targets ciliated cells in human bronchial epithelium and can cause bronchiolitis and pneumonia mostly in infants. To identify molecular targets of intervention during RSV infection in infants, we investigate how age regulates RSV interaction with the bronchial epithelium barrier. Employing precision-cut lung slices and air-liquid interface cultures generated from infant and adult human donors, we found robust RSV virus spread and extensive apoptotic cell death only in infant bronchial epithelium. In contrast, adult bronchial epithelium showed insignificant barrier damage and limited RSV infection. Single nuclear RNA-sequencing revealed age-related insufficiency of an anti-apoptotic STAT3 activation response to RSV infection in infant ciliated cells, which was exploited to facilitate virus spread via the extruded apoptotic ciliated cells carrying RSV. Activation of STAT3 and blockade of apoptosis rendered protection against severe RSV infection in infant bronchial epithelium. Lastly, apoptotic inhibitor treatment of a neonatal mouse model of RSV infection ameliorated infection and inflammation in the lung. Taken together, our findings identify a STAT3-mediated anti-apoptosis pathway as a target to battle severe RSV disease in infants.
Project description:Background: Studies in mice have shown that PPARα is an important regulator of lipid metabolism in liver and a key transcription factor involved in the adaptive response to fasting. However, much less is known about the role of PPARα in human liver. Here we set out to study the function of PPARα in human liver via analysis of whole genome gene regulation in human liver slices treated with the PPARα agonist Wy14643. Results: Quantitative PCR indicated that PPARα is well expressed in human liver and human liver slices and that the classical PPARα targets PLIN2, VLDLR, ANGPTL4, CPT1A and PDK4 are robustly induced by PPARα activation. Transcriptomics analysis indicated that 617 genes were upregulated and 665 genes were downregulated by PPARα activation (q value<0.05). Many genes induced by PPARα activation were involved in lipid metabolism (ACSL5, AGPAT9, FADS1, SLC27A4), xenobiotic metabolism (POR, ABCC2, CYP3A5) or the unfolded protein response, whereas most of the downregulated genes were involved in immune-related pathways. Among the most highly repressed genes upon PPARα activation were several chemokines (e.g. CXCL9-11, CCL8, CX3CL1, CXCL6), interferon γ-induced genes (e.g. IFITM1, IFIT1, IFIT2, IFIT3) and numerous other immune-related genes (e.g. TLR3, NOS2, and LCN2). Comparative analysis of gene regulation by Wy14643 between human liver slices and primary human hepatocytes showed that down-regulation of gene expression by PPARα is much better captured by liver slices as compared to primary hepatocytes. In particular, PPARα activation markedly suppressed immunity/inflammation-related genes in human liver slices but not in primary hepatocytes. Finally, several putative new target genes of PPARα were identified that were commonly induced by PPARα activation in the two human liver model systems, including TSKU, RHOF, CA12 and VSIG10L. Conclusion: Our manuscript demonstrates the suitability and superiority of human liver slices over primary hepatocytes for studying the functional role of PPARα in human liver. Our data underscore the major role of PPARα in regulation of hepatic lipid and xenobiotic metabolism in human liver and reveal a marked immuno-suppressive/anti-inflammatory effect of PPARα in human liver slices that may be therapeutically relevant for non-alcoholic fatty liver disease. Precision-cut liver slices, prepared from liver biopsies obtained from obese subjects undergoing bariatric surgery, were incubated with the peroxisome proliferator-activated receptor alpha (PPARα) agonist Wy14643 or vehicle for 24hrs, after which gene expression was profiled by array.
Project description:Influenza virus transmission between mothers and nursing-infants has not been investigated although mothers and infants often develop severe disease. Ferrets are considered the most appropriate model for influenza studies. We investigated influenza transmission in infant and nursing-mother ferrets. Influenza infected infants transmitted virus to mother mammary glands leading to live virus excretion in milk and influenza virus positive mammary gland epithelial cells. Global gene expression analysis showed down-regulation of milk production and induction of breast involution and oncogenesis pathways. Our results provide insight into influenza transmission between mothers and infants which may impact fields of infectious disease, maternal/infant health and neoplasm etiology. Total RNA was obtained from nursing mother ferret mammary glands at days 3/4 and 6/7 post-intranasal kit infection with 10^5 EID50 A/California/07/2009 (H1N1). Total RNA was also collected from uninfected control nursing mother mammary gland tissues (n = 3). Changes in gene expression relative to uninfected tissue controls were then investigated.
Project description:Influenza virus transmission between mothers and nursing-infants has not been investigated although mothers and infants often develop severe disease. Ferrets are considered the most appropriate model for influenza studies. We investigated influenza transmission in infant and nursing-mother ferrets. Influenza infected infants transmitted virus to mother mammary glands leading to live virus excretion in milk and influenza virus positive mammary gland epithelial cells. Global gene expression analysis showed down-regulation of milk production and induction of breast involution and oncogenesis pathways. Our results provide insight into influenza transmission between mothers and infants which may impact fields of infectious disease, maternal/infant health and neoplasm etiology. Total RNA was obtained from ferret lungs at days 3 and 6 post-intranasal infection with 10^5 EID50 A/California/07/2009 (H1N1) (n = 3/time-point). Total RNA was also collected from uninfected control lung tissues (n = 3). Changes in gene expression relative to uninfected tissue controls were then investigated.
Project description:Increased morbidity and fetal growth restriction are reported in uninfected children born to human immunodeficiency virus type 1 (HIV-1)–infected women treated with antiretroviral (ARV) therapy. Viruses and/or pharmacological interventions such as ARVs can induce metabolic stress, skewing the cell’s immune response and restricting (cell) growth. Novel metabolomic techniques provided the opportunity to investigate the impact of fetal HIV-1 and combination ARV therapy (cART) exposure on the infants’ immune metabolome. Peroxidized lipids, generated by reactive oxygen species, were increased in cART/HIV-1–exposed infants, indicating altered mitochondrial functioning. The lipid metabolism was further dysregulated with increased triglyceride species and a subsequent decrease in phospholipids in cART/HIV-1–exposed infants compared to control infants. Proinflammatory immune mediators, lysophospholipids as well as cytokines such as CXCL10 and CCL3, were increased whereas anti-inflammatory metabolites from the cytochrome P450 pathway were reduced in cART/HIV-1–exposed infants. Taken together, these data demonstrate that the fetal metabolism is impacted by maternal factors (cART and HIV-1) and skews physiological immune responses toward inflammation in the newborn infant.
Project description:Bacterial-derived immune training agents are a showing promise in clinical studies for prevention of lower respiatory infections in high-risk infants but underlying mechanisms of this protective effect are unclear. To address this, we employed a systems-level analysis of transcriptional responses to immune stimuli (LPS and PolyI:C) in infants who participated in a clinical trial of one such agent called OM85 which was clinically effective. We identified key protected innate immune changes using a series of analytical approaches such as reduced inflammatory responses to LPS and enhanced antibacterial interferon responses potentially mediated through IRF7. We posit that immune training agents exemplified by OM85 potentially protect against infant severe lower respiratory infection principally via effects on innate immune responses targeting the bacterial components of the mixed respiratory viral/bacterial infections which are characteristic of this age group.
Project description:In perinatal HIV infection, early ART initiation is recommended but questions remain regarding infant immune responses to HIV and impact of HIV on immune development. Using single cell transcriptional and phenotypic analysis we evaluated the T cell compartment at pre-ART initiation of infants with perinatally acquired HIV from Maputo, Mozambique (TARA cohort). CD8+ T cell maturation subsets exhibited altered distribution in HIV exposed infected (HEI) infants relative to control infants (HIV exposed uninfected) with reduced naïve, increased effectors, higher frequencies of activated T cells, and lower frequencies of cells with markers of self-renewal. Additionally, a cluster of CD8+ T cells identified in HEI displayed gene profiles consistent with cytotoxic T lymphocytes (CTL) and showed evidence for hyper expansion. Longitudinal phenotypic analysis revealed accelerated maturation of CD8+ T cells was maintained in HEI despite viral control. The results point to a HIV directed immune response that is likely to influence reservoir establishment.