Biology subjects

Sureshchandra, S.

Publications and source records attributed to Sureshchandra, S..

7 recordsLinked to original sources

bioRxiv2021

Deep immune profiling of the maternal-fetal interface with mild SARS-CoV-2 infection

Pregnant women are an at-risk group for severe COVID-19, though the majority experience mild/asymptomatic disease. Although severe COVID-19 has been shown to be associated with immune activation at the maternal-fetal interface even in the absence of active viral replication, the immune response to asymptomatic/mild COVID-19 remains unknown. Here, we assessed immunological adaptations in both blood and term decidua from 9 SARS-exposed pregnant women with asymptomatic/mild disease and 15 pregnant SARS-naive women. In addition to selective loss of tissue-resident decidual macrophages, we report attenuation of antigen presentation and type I IFN signaling but upregulation of inflammatory cytokines and chemokines in blood monocyte derived decidual macrophages. On the other hand, infection was associated with remodeling of the T cell compartment with increased frequencies of activated CD69+ tissue-resident T cells and decreased abundance of Tregs. Interestingly, frequencies of cytotoxic CD4 and CD8 T cells increased only in the blood, while CD8 effector memory T cells were expanded in the decidua. In contrast to decidual macrophages, signatures of type I IFN signaling were increased in decidual T cells. Finally, T cell receptor diversity was significantly reduced with infection in both compartments, albeit to a much greater extent in the blood. The resulting aberrant immune activation in the placenta, even with asymptomatic disease may alter the exquisitely sensitive developing fetal immune system, leading to long-term adverse outcomes for offspring.

immunology↗

bioRxiv2021

Chronic ethanol drinking in non-human primates induces inflammatory cathepsin gene expression in alveolar macrophages accompanied by functional defects

Chronic alcohol drinking is associated with increased susceptibility to viral and bacterial respiratory pathogens. Investigating the effects of alcohol on the lung is challenging in humans because of the complexity of human drinking behavior and the challenge of obtaining samples. In this study, we utilize a rhesus macaque model of voluntary ethanol self-administration to study the effects of alcohol on the lung in a physiologically and genetically relevant model. We report a heightened activation and inflammatory state in alveolar macrophages (AM) obtained from ethanol drinking animals that is accompanied by increased chromatin accessibility in intergenic regions that regulate inflammatory genes and contain binding motifs for transcription factors AP-1, IRF8, and NFKB p-65. In line with these transcriptional and epigenetic changes at basal state, AM from ethanol drinking animals generate elevated inflammatory mediator responses to LPS and respiratory syncytial virus (RSV). Analysis using scRNA-Seq revealed heterogeneity in lung-resident macrophage and monocyte populations, including increased abundance of activated and cathepsin-expressing clusters and accelerated differentiation with ethanol. Finally, functional assays show increased mitochondrial content in AM from ethanol drinking animals, which is associated with observed increased ROS and decreased phagocytosis capacity. This comprehensive epigenomic, transcriptional and functional profiling of lung macrophages after ethanol drinking in macaques provides previously unidentified mechanisms of ethanol induced infection susceptibility in patients with alcohol use disorders.

immunology↗

bioRxiv2021

Exploratory extracellular vesicle-bound miRNA profiling to identify candidate biomarkers of chronic alcohol drinking in non-human primates

BackgroundLong-term alcohol drinking is associated with numerous health complications including susceptibility to infection, cancer, and organ damage. However, due to the complex nature of human drinking behavior, it is challenging to determine whether alcohol use should be considered a risk factor during diagnosis and treatment. We lack reliable biomarkers of alcohol use that could be used to determine drinking behavior prior to signs of overt organ damage. Recently, extracellular vesicle-bound microRNA (EV-miRNA) have been discovered to be consistent biomarkers of conditions including cancer and liver disease. MethodsIn this study, we profiled the plasma EV-miRNA content by miRNA-Seq from 80 non-human primates after 12 months of voluntary ethanol drinking. ResultsWe identified a list of up- and downregulated EV-miRNA candidate biomarkers of both heavy drinking as well as those positively correlated with ethanol dose. We further overexpressed these candidate miRNA in control primary peripheral immune cells to assess potential functional mechanisms of these EV-miRNA. We identified that overexpression of miR-155, miR-154, miR-34c, miR-450a, and miR-204 led to increased inflammatory TNF or IL-6 production in PBMC after stimulation. ConclusionThis exploratory study identified several EV-miRNA that could serve as biomarkers of long-term alcohol drinking as well as provided a mechanism for alcohol-induced peripheral inflammation.

molecular biology↗

bioRxiv2021

Single cell profiling of T and B cell repertoires following SARS-CoV-2 mRNA vaccine

mRNA based vaccines for SARS-CoV-2 have shown exceptional clinical efficacy providing robust protection against severe disease. However, our understanding of transcriptional and repertoire changes following full vaccination remains incomplete. We used single-cell RNA sequencing and functional assays to compare humoral and cellular responses to two doses of mRNA vaccine with responses observed in convalescent individuals with asymptomatic disease. Our analyses revealed enrichment of spike-specific B cells, activated CD4 T cells, and robust antigen-specific polyfunctional CD4 T cell responses in all vaccinees. On the other hand, CD8 T cell responses were both weak and variable. Interestingly, clonally expanded CD8 T cells were observed in every vaccinee, as observed following natural infection. TCR gene usage, however, was variable, reflecting the diversity of repertoires and MHC polymorphism in the human population. Natural infection induced expansion of larger CD8 T cell clones occupied distinct clusters, likely due to the recognition of a broader set of viral epitopes presented by the virus not seen in the mRNA vaccine. Our study highlights a coordinated adaptive immune response where early CD4 T cell responses facilitate the development of the B cell response and substantial expansion of effector CD8 T cells, together capable of contributing to future recall responses.

immunology↗

bioRxiv2021

Transcriptional, epigenetic, and functional reprogramming of blood monocytes in non-human primates following chronic alcohol drinking

Chronic heavy drinking (CHD) of alcohol is a known risk factor for increased susceptibility to bacterial and viral infection as well as impaired wound healing. Evidence suggests that these defects are mediated by a dysregulated inflammatory response originating from myeloid cells, notably monocytes and macrophages, but the mechanisms remain poorly understood. Our ability to study CHD is impacted by the complexities of human drinking patterns and behavior as well as comorbidities and confounding risk factors for patients with alcohol use disorders. To overcome these challenges, we utilize a translational rhesus macaque model of voluntary ethanol self-administration that closely recapitulates human drinking patterns and chronicity. In this study, we examined the effects of CHD on blood monocytes and alveolar macrophages in control and CHD female macaques after 12 months of daily ethanol consumption. While monocytes from CHD female macaques generated a hyper-inflammatory response to ex vivo LPS stimulation, their response to E.Coli was dampened. In depth scRNA-Seq analysis of purified monocytes revealed significant shifts in classical monocyte subsets with accumulation of cells expressing markers of hypoxia (HIF1A) and inflammation (NFkB signaling pathway) in CHD macaques. The increased presence of monocyte subsets poised to generate a hyperinflammatory response was confirmed by the epigenetic analysis which revealed higher accessibility of promoter regions that regulate genes involved in cytokine signaling pathways. Finally, alveolar macrophages (AM) from the same animals produced higher levels of inflammatory mediators in response to LPS stimulation, but reduced ability to phagocytose bacteria. Collectively, data presented in this manuscript demonstrate that CHD primes monocytes and tissue-resident macrophages towards a more hyper-inflammatory immune response with compromised functional abilities, which could be used in diagnostic purposes or preventative measures for patients with alcohol use disorders.

immunology↗

bioRxiv2021

Maternal Obesity Dysregulates Fetal Hematopoietic Stem and Progenitor Cell Development in Rhesus Macaques

BackgroundMaternal obesity adversely impacts the in utero metabolic environment and offsprings health, but its effect on fetal hematopoiesis and immune cell development remains incompletely understood, particularly in models that resemble human development. MethodsWe studied gestational day 130-135 fetuses derived from rhesus macaque dams chronically exposed to a high-fat Western-style diet (WSD) or a low-fat control diet. Fetal immune cell phenotypes and fetal bone marrow architecture and hematopoietic stem and progenitor cell (FBM HSPC) function were examined using bone computed tomography, histology, flow cytometry, single-cell RNA-sequencing, and HSPC transplantation assays. FindingsMaternal WSD induced premature FBM cavity opening and a codominant increase in the number of FBM adipocytes. Furthermore, a maternal WSD induced a proinflammatory transcriptional response in FBM HSPCs. FBM macrophages from the WSD group exhibited heightened proinflammatory responses to toll-like receptor agonist stimulation. Maternal WSD exposure suppressed the expression of genes required for B-cell development and decreased the frequencies of FBM B-cells. Finally, maternal WSD led to poor engraftment of FBM HSPCs in nonlethally irradiated immunodeficient NOD/SCID/IL2r{gamma}-/- mice. InterpretationsMaternal WSD impairs FBM development, drives a hyperinflammatory phenotype, and induces functional and differentiation impairment in FBM HSPCs in a translationally relevant nonhuman primate model. FundingNational Institute of Health RESEARCH IN CONTEXTO_ST_ABSEvidence before this studyC_ST_ABSMaternal obesity is associated with increased risk of infections and proinflammatory disease in offspring. The translationally-relevant rhesus macaque model was utilized to address the effects of maternal obesogenic diet on fetal hematopoietic and immune cell development. Added value of this studyWe assessed changes in fetal immune cell phenotypes and fetal hematopoietic stem and progenitor cell function using immunohistochemistry, flow cytometry, single-cell RNA sequencing, and transplantation assays. We determined that chronic consumption of a maternal obesogenic diet induced the development of adipogenic and proinflammatory environments in the fetal bone marrow. Additionally, we detected the impairment in B-cell differentiation program in fetal hematopoietic stem and progenitor cells. Implications of all the available evidenceThese data demonstrate that maternal obesogenic diet modulates fetal hematopoietic development and could impact the offsprings immune system, including proinflammatory phenotype and a decline in B-cell function.

immunology↗

bioRxiv2020

Functional and genomic adaptations of blood monocytes to pregravid obesity during pregnancy

Pre-pregnancy obesity is associated with several adverse maternal health outcomes, notably increased risk of infection as well as the incidence of gestational diabetes, preeclampsia, and preterm birth. However, the mechanisms by which pregravid obesity disrupts the pregnancy associated "immune clock" are still unknown. To address this question, we collected blood samples from women during the first and third trimesters and determined the impact of both pregnancy and pregravid obesity on circulating immune mediators, immune cell subset frequencies, and peripheral immune responses. While regardless of BMI, pregnancy was associated with an elevation in both Th1 and Th2 cytokines, pregravid obesity was associated with a dysregulation in circulating myeloid factors at term. Moreover, pregnancy in lean subjects was associated with enhanced monocyte activation, augmented chromatin accessibility at inflammatory loci, and heightened responses to LPS. Pregravid obesity disrupted this trajectory and was accompanied by a lack of transcriptional and epigenetic changes and alterations in metabolic status strongly suggesting a skewing towards immunotolerance. These findings provide novel insight into the increased susceptibility to infections observed with obesity during pregnancy. SUMMARYA healthy pregnancy is associated with progressive innate immune activation. Maternal factors such as obesity compromise this myeloid cell activation trajectory at genomic, epigenomic, functional, and metabolic levels, resulting in stagnant immune responses, suggestive of a state of tolerance.

immunology↗