Biology subjects

Sonar, S. A.

Publications and source records attributed to Sonar, S. A..

3 recordsLinked to original sources

bioRxiv2023

RORyt+CD4+ T cells promote IL-23R-mediated neuronal cell apoptosis in the central nervous system

Transcription factors T-bet and ROR{psi}t play a crucial role in neuronal autoimmunity, and mice deficient in these two factors do not develop experimental autoimmune encephalomyelitis (EAE). The independent role of T-bet and ROR{psi}t in the pathogenesis of EAE and how they help induce apoptosis of neurons in the central nervous system (CNS) during neuronal autoimmunity is unclear. In the present study, we showed that myelin oligodendrocyte glycoprotein (MOG35-55) peptide-specific Th1 cells deficient in ROR{psi}t could cross BBB but fail to induce apoptosis of neurons and EAE. Pathogenic Th17 cell-derived cytokines GM-CSF, TNF-, IL-17A, and IL-21 significantly increase the surface expression of IL-23R on neuronal cells. Furthermore, we showed that, in EAE, neurons in the brain and spinal cord express IL-23R. IL-23-IL-23R signaling in neuronal cells caused phosphorylation of STAT3 (Ser727 and Tyr705) and induced cleaved caspase 3 and cleaved poly (ADP-ribose) polymerase-1 (PARP-1) molecules in an IL-23R-dependent manner and caused apoptosis. Thus, we provided a mechanism where we showed that T-bet is required to recruit pathogenic Th17 cells and ROR{psi}t expression to drive the apoptosis of IL-23R+ neurons in the CNS and cause EAE. Understanding detailed molecular mechanisms will help to design better strategies to control neuroinflammation and autoimmunity. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/537133v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@2586b0org.highwire.dtl.DTLVardef@1adb3deorg.highwire.dtl.DTLVardef@fbce53org.highwire.dtl.DTLVardef@1a6d4ae_HPS_FORMAT_FIGEXP M_FIG C_FIG One Sentence SummaryIL-23-IL-23R signaling promotes apoptosis of CNS neurons.

immunology↗

bioRxiv2022

T-cell cellular stress and reticulocyte signatures, but not loss of naive T lymphocytes, characterize severe COVID-19 in older adults

In children and younger adults up to 39 years of age, SARS-CoV-2 usually elicits mild symptoms that resemble the common cold. Disease severity increases with age starting at 30 and reaches astounding mortality rates that are ~330 fold higher in persons above 85 years of age compared to those 18-39 years old. To understand age-specific immune pathobiology of COVID-19 we have analyzed soluble mediators, cellular phenotypes, and transcriptome from over 80 COVID-19 patients of varying ages and disease severity, carefully controlling for age as a variable. We found that reticulocyte numbers and peripheral blood transcriptional signatures robustly correlated with disease severity. By contrast, decreased numbers and proportion of naive T-cells, reported previously as a COVID-19 severity risk factor, were found to be general features of aging and not of COVID-19 severity, as they readily occurred in older participants experiencing only mild or no disease at all. Single-cell transcriptional signatures across age and severity groups showed that severe but not moderate/mild COVID-19 causes cell stress response in different T-cell populations, and some of that stress was unique to old severe participants, suggesting that in severe disease of older adults, these defenders of the organism may be disabled from performing immune protection. These findings shed new light on interactions between age and disease severity in COVID-19.

immunology↗

bioRxiv2021

Early age-related atrophy of cutaneous lymph nodes precipitates an early functional decline in skin immunity in mice with aging

Secondary lymphoid organs (SLO; including the spleen and lymph nodes) are critical both for the maintenance of naive T (TN) lymphocytes and for the initiation and coordination of immune responses. How they age, including the exact timing, extent, physiological relevance, and the nature of age-related changes, remains incompletely understood. We used time-stamping to indelibly mark cohorts of newly generated naive T cells (a.k.a. recent thymic emigrants - RTE) in mice, and followed their presence, phenotype and retention in SLO. We found that SLO involute asynchronously. Skin-draining lymph nodes (LN) atrophied early (6-9 months) in life and deeper tissue-draining LN and the spleen late (18-20 months), as measured by the loss of both TN numbers and the fibroblastic reticular cell (FRC) network. Time-stamped RTE cohorts of all ages entered SLO and successfully completed post-thymic differentiation. However, in older mice, these cells were poorly retained, and those found in SLO exhibited an emigration phenotype (CCR7loS1P1hi). Transfers of adult RTE into recipients of different ages formally demonstrated that the defect segregates with the age of the SLO microenvironment and not with the age of T cells. Finally, upon intradermal immunization, RTE generated in mice as early as 6-7 months of age barely participated in de novo immune responses and failed to produce well-armed effector cells. These results highlight changes in structure and function of superficial secondary lymphoid organs in laboratory mice that are earlier than expected and are consistent with the long-appreciated and pronounced reduction of cutaneous immunity with aging.

immunology↗