Project description:<p>Whole exome sequencing of a trio (parents and offspring) reveals PIK3CG mutations that result in loss of protein in the child with immunodeficiency and immunopathology.</p>
Project description:Phosphatidylinositol 3-kinase-gamma (PI3Kγ) is highly expressed in leukocytes and is an attractive drug target for immune modulation. Different experimental systems have led to conflicting conclusions regarding inflammatory and anti-inflammatory functions of PI3Kγ. Here, we report a human patient with bi-allelic, loss-of-function mutations in PIK3CG resulting in absence of the p110γ catalytic subunit of PI3Kγ. She has a history of childhood-onset antibody defects, cytopenias, and T lymphocytic pneumonitis and colitis, with reduced peripheral blood memory B, memory CD8+ T, and regulatory T cells and increased CXCR3+ tissue-homing CD4 T cells. PI3Kγ-deficient macrophages and monocytes produce elevated inflammatory IL-12 and IL-23 in a GSK3α/β-dependent manner upon TLR stimulation. Pik3cg-deficient mice recapitulate major features of human disease after exposure to natural microbiota through co-housing with pet-store mice. Together, our results emphasize the physiological importance of PI3Kγ in restraining inflammation and promoting appropriate adaptive immune responses in both humans and mice.
Project description:In our study we aimed to analyze the gene expression profile of Treg cells in CVID and SIgAD patients, compared to age-matched healthy controls. Selective IgA deficiency (SIgAD) is the most common and common variable immunodeficiency (CVID) is the most symptomatic form of predominant antibody deficiency. Despite differences in the clinical picture, a similar genetic background is suggested. A common feature of both disorders is the occurrence of autoimmune conditions. Regulatory T cells (Tregs) are the major immune cell type that maintains autoimmune tolerance. As the different types of abnormalities of Treg cells were associated with autoimmune disorders in primary immunodeficiency (PID) patients, in our study we aimed to analyze the gene expression profile of Treg cells in CVID and SIgAD patients, compared to age-matched healthy controls. The transcriptome-wide gene profiling was performed using microarray technology. As a results, we analyzed and visualized global expression patterns of genes and pathways of isolated population of Treg cells. We showed the differences at gene-level between patients with and without autoimmunizations. Our finding suggest that gene signature of Treg cells isolated from SIgAD and CVID patients differ from age-matched healthy controls and form each other, while the occurrence of autoimmunity in both PID is associated with IFN signaling pathway. In sum, our findings improve our understanding of Treg dysfunctions in patients with common PIDs and associated autoimmunity.
Project description:Clinically, obesity is strongly associated with severe TH2 immunopathology, though the physiological, cellular, and molecular underpinnings of this association remain obscure. We demonstrate that obese mice are susceptible to severe atopic dermatitis (AD), a major manifestation of TH2 immunopathology and disease burden in humans. Mechanistically, we show that dysregulation of the nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARg) in T cells is a causal link between obesity and the increased TH2 immunopathology. We find that PPARg directly controls a cellular metabolic transcriptional program that restrains nuclear gene expression of the chief TH2 effector cytokines interleukin-4 (IL-4) and interleukin-13 (IL-13). Accordingly, thiazolidinediones (TZDs), potent PPARg agonists, robustly protect obese mice from TH2 immunopathology. Collectively, these findings establish PPARg as a molecular link between obesity and TH2 immune homeostasis and identify TZDs as novel therapeutic candidates for TH2 immunopathology.