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Girondier, L.

Publications and source records attributed to Girondier, L..

2 recordsLinked to original sources

Single Spectral Flow Cytometry Panel for Simultaneous Detection of Hematopoietic Stem, Progenitor, and Mature Lineages in Mouse Bone Marrow

Hematopoiesis occurs in the bone marrow of adult mammals and is supported by hematopoietic stem cells that sustain lifelong blood cell production. Pathological conditions can disrupt HSC differentiation, causing anaemia, immunodeficiency, and other cytopenias. Therefore, precise and simultaneous identification of hematopoietic populations from stem to mature cells is essential for understanding disease mechanisms and developing targeted therapies. In order to study these alterations, flow cytometry is generally a need-to-have monitoring technique. However, most cytometry panels are designed to thoroughly study a particular population, leaving out potential discoveries on other populations from the same microenvironment. Here we present the design of complex 19-marker spectral flow cytometry panel capable of simultaneously identifying HSPCs, erythroid, myeloid and lymphoid cells within a single murine BM sample. This integrated approach replaces multiple conventional panels and enables comprehensive mapping of hematopoietic differentiation from a single assay. Validation confirmed accurate detection of long-term and short-term HSCs, multipotent progenitors, common myeloid and lymphoid progenitors, and erythroid populations from proerythroblasts to reticulocytes. UMAP visualization captured the continuous trajectory of differentiation. We validated our method on aged and {beta}-thalassemic mouse models showing a clear detection of hematopoiesis and erythropoiesis alterations respectively. This panel provides a robust, flexible, and scalable platform suitable for both basic research and translational studies.

physiology↗

Non-canonical TERT function mitigates adipose tissue inflammation in obesity by modulating stem cell-macrophage communication and macrophage states

Background and aimsObesity drives adipose tissue (AT) expansion and chronic inflammation, leading to metabolic dysfunction through adipocyte hypertrophy, impaired ASPC differentiation, immune infiltration, and fibrosis. Stromal vascular remodeling prominently features expansion of Gdf15- and Trem2-expressing lipid-associated macrophages (LAMs), which respond to adipocyte stress and act as lipid scavengers to buffer excess lipids released by adipocytes. Here, we examined macrophage reprogramming in p21+/Tert and p21+/TertCi mice, which express active TERT or its catalytically inactive TERTCi mutant from the endogenous Cdkn1a promoter. ResultsFollowing HFD exposure, conditional expression of TERT or TERTCi resulted in a pronounced downregulation of p21 in macrophage subsets, accompanied by a reduction in AT inflammation. Notably, TERT and TERTCi expression reshaped the adipose-tissue macrophage (ATM) landscape depleting Trem2+ and Gdf15+ LAMs while preserving resident macrophages. This shift was accompanied by marked suppression of the Trem2 transcriptional program and down-regulation of PPAR-{gamma} and NR1H3 in LAMs and by impaired ASPC-LAM signaling pathways that normally drive LAM recruitment and activation. Proteomic profiling further showed that p21+/Tert ASPCs secreted markedly higher levels of proteins associated with non-conventional secretion, while extracellular matrix-associated factors and cytokines/chemokines including key mediators of ASPC-LAM communication such as Ccl2, C3, and Csf1 were substantially reduced. However, only p21+/Tert mice, and not p21+/TertCi mice, exhibited significant metabolic improvements, indicating that macrophage remodeling alone is insufficient to restore systemic metabolic function. Consistent with this, enhanced ASPC expansion and differentiation, supporting improved adipose-tissue remodeling, was observed exclusively in p21+/Tert obese mice. ConclusionsTERT remodels adipose tissue immunity independently of its enzymatic activity, and TERT-driven reprogramming of the ASPC secretome may emerge as a promising strategy to combat obesity-related metabolic dysfunction. HighlightsO_LIConditional expression of TERT or catalytically inactive TERTCi results in the depletion Trem2+ and Gdf15+ LAMs while preserving resident macrophages C_LIO_LITERT and TERTCi expression impairs ASPC-adipocyte/LAM communication pathways that normally drive LAM recruitment and activation. C_LIO_LIIn vitro, TERT conditional expression in ASPCs promotes non-conventional protein secretion and reduces the secretion of key mediators of ASPC-LAM communication C_LIO_LIOnly p21+/Tert mice, and not p21+/TertCi mice, exhibited enhanced ASPC expansion, improved adipose-tissue remodeling, and systemic metabolic benefits, demonstrating that macrophage remodeling alone is insufficient to restore metabolic function. C_LI

physiology↗