Biology subjects

Lamarche, C.

Publications and source records attributed to Lamarche, C..

3 recordsLinked to original sources

bioRxiv2023

Identification of inflammatory biomarkers in IgA nephropathy using the NanoString technology: a validation study

Objective and designImmunoglobulin A nephropathy (IgAN) is a kidney disease characterized by the accumulation of IgA deposits in the glomeruli of the kidney, leading to inflammation and damage to the kidney. The inflammatory markers involved in IgAN remain to be defined. Gene expression analysis platforms, such as the NanoString nCounter system, are promising screening and diagnostic tools, especially in the oncology field, but its role as a diagnostic and prognostic tool in IgAN remains scarce. In this study, we aimed to validate the use of NanoString technology to identify potential inflammatory biomarkers involved in the progression of IgAN. SubjectsA total of 30 patients with biopsy-proven IgAN and 7 cases of antineutrophil cytoplasmic antoantibodies (ANCA) associated pauci-immune glomerulonephritis were included for gene expression measurement. For the immunofluorescence validation experiments, a total of 6 IgAN patients and 3 healthy controls were included. MethodsTotal RNA was extracted from formalin-fixed-paraffin-embedded kidney biopsy specimens, and a customized 48-plex human gene CodeSet was used to study 29 genes implicated in different biological pathways. Comparisons in gene expression were made between IgAN and ANCA-associated pauci-immune glomerulonephritis patients to delineate an expression profile specific to IgAN. Gene expression was compared between patients with low and moderate risk of progression. Genes for which RNA expression was associated with disease progression were analyzed for protein expression by immunofluorescence, and compared with healthy controls. ResultsIgAN patients had a distinct gene expression profile with decreased expression in genes IL-6, INFG and C1QB compared to ANCA patients. C3 and TNFR2 were identified as potential biomarkers for IgAN progression in patients early in their disease course. Protein expression for those 2 candidate genes was upregulated in IgAN patients compared to controls. Expression of genes implicated in fibrosis (PTEN, CASPASE 3, TGM2, TGFB1, IL2, and TNFRSF1B) was more pronounced in IgAN patient with severe fibrosis compared to those with none. ConclusionsOur findings validate our NanoString mRNA profiling by examining protein expression levels of two candidate genes, C3 and TNFR2, in IgAN patients and healthy controls. We were also able to identify several upregulated mRNA transcripts implicated in the development of fibrosis that may be considered as fibrotic markers within IgAN patients.

genomics↗

bioRxiv2022

A third SARS-CoV-2 mRNA vaccine dose in people receiving hemodialysis overcomes B cell defects but elicits a skewed CD4+ T cell profile

Cellular immune defects associated with suboptimal responses to SARS-CoV-2 mRNA vaccination in people receiving hemodialysis (HD) are poorly understood. We longitudinally analyzed antibody, B cell, CD4+ and CD8+ T cell vaccine responses in 27 HD patients and 26 low-risk control individuals (CI). The first two doses elicit weaker B cell and CD8+ T cell responses in HD than in CI, while CD4+ T cell responses are quantitatively similar. In HD, a third dose robustly boosts B cell responses, leads to convergent CD8+ T cell responses and enhances comparatively more Thelper (TH) immunity. Unsupervised clustering of single-cell features reveals phenotypic and functional shifts over time and between cohorts. The third dose attenuates some features of TH cells in HD (TNF/IL-2 skewing), while others (CCR6, CXCR6, PD-1 and HLA-DR overexpression) persist. Therefore, a third vaccine dose is critical to achieve robust multifaceted immunity in hemodialysis patients, although some distinct TH characteristics endure.

immunology↗

bioRxiv2020

Repeated stimulation or tonic-signaling chimeric antigen receptors drive regulatory T cell exhaustion

Regulatory T cell (Treg) therapy is a promising approach to improve outcomes in transplantation and autoimmunity. In conventional T cell therapy, chronic stimulation can result in poor in vivo function, a phenomenon termed exhaustion. Whether or not Tregs are also susceptible to exhaustion, and if so, if this would limit their therapeutic effect, was unknown. We studied how two methods which induce conventional T cell exhaustion – repetitive stimulation or expression of a tonic-signaling chimeric antigen receptor (CAR) – affect human Tregs. With each repetitive polyclonal stimulation Tregs progressively acquired an exhausted phenotype, and became less suppressive in vitro. Tregs expressing a tonic-signaling CAR rapidly acquired an exhausted phenotype and had major changes in their transcriptome and metabolism. Although tonic-signaling CAR-Tregs remained stable and suppressive in vitro, they lost in vivo function, as tested in a model of xenogeneic graft-versus-host disease. The finding that human Tregs are susceptible to exhaustion has important implications for the design of Treg adoptive immunotherapy strategies.Competing Interest StatementMKL received research funding from TxCell, Bristol-Myers Squibb, Pfizer, Takeda and CRISPR Therapeutics for work unrelated to this report. CLM holds several patent applications in the area of CAR based immunotherapy, and is a founder of, holds equity in, and receives consulting fees from Lyell Immunopharma which develops CAR based therapies. EWW holds several patent applications in the area of CAR based immunotherapy and receives consulting fees from Lyell Immunopharma. CLM is a member of the Parker Institute for Cancer Immunotherapy, which supports the Stanford University Cancer Immunotherapy Program.AbbreviationsCARChimeric antigen receptorECARextracellular acidification rateOCARoxygen consumption rateTconvconventional T cellTregRegulatory T cellTStonic signalingTSDRRegulatory T-cell-Specific Demethylated RegionView Full Text

immunology↗