Laëtitia Kermarrec

Laëtitia Kermarrec
University of Manitoba | UMN · Department of Immunology

Bsc, MSc, PhD

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31
Publications
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Publications

Publications (31)
Article
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The pro-inflammatory mediator receptor activator of nuclear factor-kappa B ligand (RANKL) plays a significant role in the development of rheumatoid arthritis; however, its role in inflammatory bowel disease is unknown. Genome-wide association meta-analysis for Crohn’s disease (CD) identified a variant near the TNFSF11 gene that encodes RANKL and CD...
Article
It remains unknown what causes inflammatory bowel disease (IBD), including signaling networks perpetuating chronic gastrointestinal inflammation in Crohn's disease (CD) and ulcerative colitis (UC), in humans. According to an analysis of up to 500 patients with IBD and 100 controls, we report that key transcripts of the IL-7 receptor (IL-7R) pathway...
Article
Background and purpose: An alteration in the communication between the innate and adaptive immune cells is a hallmark of ulcerative colitis (UC). Semaphorin-3E (SEMA3E), a secreted guidance protein, regulates various immune responses. Experimental approach: We investigated the expression of SEMA3E in colonic biopsies of active UC patients and it...
Article
Background Neuroimmune interactions are essential to maintain gut homeostasis and prevent intestinal disorders but so far, the impact of enteric glial cells (EGC) on immune cells remains a relatively unexplored area of research. As a dysregulation of critical cytokines such as interleukine‐7 (IL‐7) was suggested to exacerbate gut chronic inflammati...
Article
Full-text available
Background Ulcerative colitis (UC) is characterized by altered levels of chromogranin-A (CHGA) and a dysregulation of dendritic cells (DCs). CHGA, a prohormone protein, can be cleaved into several bioactive peptides including chromofungin (CHR: CHGA47-66) encoded by CHGA Exon-IV. Previously, we demonstrated that CHR is reduced in active UC patients...
Article
Full-text available
Background Ulcerative colitis (UC) is characterized by an alterations of tight junction (TJ) barrier and immune responses that result in abnormal passages of exogenous antigens such as gut-derived bacterial lipopolysaccharides (LPS). Semaphorin-3E (Sema3E) and its receptor plexin D1 (PLXD1R) are key regulators of epithelia and immune systems Aims...
Article
Full-text available
Background Chromogranin-A (CgA) is elevated in inflammatory bowel disease (IBD) and in murine models of colitis. CgA produced by enteroendocrine cells can be cleaved in several peptides including the immunoregulatory pancreastatin (PTS: CgA273-301). Macrophages (Mo) play a major role in IBD through an impaired transition from a pro-inflammatory (cl...
Article
Full-text available
Background Chromogranin-A (CHGA) levels are increased in inflammatory bowel disease (IBD) and murine models of colitis. CHGA is cleaved in several peptides including the immunoregulatory pancreastatin (PST: CHGA273-301), which encodes by CHGA exon-VII. Classically activated macrophages (M1) and signal transducer and activator of transcription (STAT...
Article
Full-text available
Background Inflammatory bowel diseases (IBD) involve an increase of dendritic cells (DC) infiltration and cytokines production. Recently, semaphorins have been implicated in inflammation and cell migration and has emerged as an essential axis in DC immune responses. Aims This study aims to determine the role of Sema3E on DC regulation during colit...
Article
Full-text available
Chromogranin-A (CHGA) is elevated in inflammatory bowel disease (IBD), but little is known about its role in colonic inflammation. IBD is associated with impaired functions of macrophages and increased apoptosis of intestinal epithelial cells. We investigated CHGA expression in human subjects with active ulcerative colitis (UC) and the underlying m...
Article
Full-text available
Ulcerative colitis (UC) is characterized by a functional dysregulation of alternatively activated macrophage (AAM) and intestinal epithelial cells (IECs) homeostasis. Chromogranin-A (CHGA) secreted by neuroendocrine cells is implicated in intestinal inflammation and immune dysregulation. CHGA undergoes proteolytic processing to generate CHGA-derive...
Article
Full-text available
Ulcerative colitis (UC) is characterized by a functional dysregulation of alternatively activated macrophage (AAM) and intestinal epithelial cells (IECs) homeostasis. Chromogranin-A (CHGA) secreted by neuroendocrine cells is implicated in intestinal inflammation and immune dysregulation. CHGA undergoes proteolytic processing to generate CHGA-derive...
Article
Full-text available
While there is growing awareness of a relationship between chromogranin-A (CHGA) and susceptibility to inflammatory conditions, the role of human catestatin [(hCTS); CHGA352–67] in the natural history of established inflammatory bowel disease is not known. Recently, using two different experimental models, we demonstrated that hCTS-treated mice dev...
Chapter
Understanding the cross talk between the immune system and cerebellum development has noticeable implications for understanding and management of neurodevelopmental disorders. Our knowledge about cerebellar developmental maturation and remodeling is improving. Immune cells have different functions in a healthy state, but those functions are comprom...
Article
Full-text available
2,4-Dinitrobenzene sulfonic acid (DNBS)-induced colitis is an experimental model that mimics Crohn’s disease. Appropriateness of reference genes is crucial for RT-qPCR. This is the first study to determine the stability of reference gene expression (RGE) in mice treated with DNBS. DNBS experimental Colitis was induced in male C57BL/6 mice. RNA was...
Article
Full-text available
The postnatal period is crucial for the development of gastrointestinal (GI) functions. The enteric nervous system is a key regulator of GI functions and increasing evidences indicate that 1) postnatal maturation of enteric neurons has an impact on the development of GI functions, and 2) microbiota-derived short-chain fatty acid can be involved in...
Article
Enteric glial cells (EGC) have trophic and neuroregulatory functions in the enteric nervous system, but whether they exert a direct effect on immune cells is unknown. Here, we used co-cultures to show that human EGC can inhibit the proliferation of activated T lymphocytes. Interestingly, EGC from Crohn's patients were effective at one EGC for two T...
Article
Full-text available
Foetal pig neuroblasts are interesting candidates as a cell source for transplantation, but xenotransplantation in the brain requires the development of adapted immunosuppressive treatments. As systemic administration of high doses of cyclosporine A has side effects and does not protect xenotransplants forever, we focused our work on local control...

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Quantitative real-time polymerase chain reaction (RT-qPCR) is a powerful technique used to increase our understanding of the molecular pathophysiology of IBD, and it is characterized by a high sensitivity, a relatively low cost, and a high time efficiency. RT-qPCR accuracy is affected by the stability of the reference genes. Therefore, careful selection, evaluation and validation of the optimal reference gene are vital for achieving reliable results and to avoid possible data inaccuracies from the use of a suboptimal reference gene. Because of their low cost and rapid onset of disease, chemical-induced colitis models are considered valuable tools to study various aspects of IBD. The dextran sulfate sodium (DSS) model, a model of injury-repair mimicking UC, while DNBS model, a model mimicking CD