Biology subjects

Charmoy, M.

Publications and source records attributed to Charmoy, M..

2 recordsLinked to original sources

bioRxiv2023

Induction of mitophagy reverts age-associated decline of the hematopoietic and immune systems

Aging compromises hematopoietic and immune system functions, making elderly individuals especially susceptible to hematopoietic failure, infections and tumor development and thus representing an important medical target for a broad range of diseases. During aging, hematopoietic stem cells (HSCs) lose their blood reconstitution capability and commit preferentially toward myeloid lineage (myeloid-bias). These processes are accompanied by an aberrant accumulation of mitochondria in HSCs. The administration of the mitophagy-inducer Urolithin-A re-establishes the correct mitochondrial homeostasis in HSCs and completely restores the blood reconstitution capability of "old" HSCs. Moreover, Urolithin-A supplemented food restores lymphoid compartments, boosts HSCs function and improves the immune response to viral infection in old mice. Altogether our results demonstrate that targeting mitophagy reverts aging phenotype in the hematopoietic and immune system.

immunology↗

bioRxiv2022

NFAT5 induction by the tumor microenvironment enforces CD8 T cell exhaustion

Persistent exposure to antigen during chronic infection or cancer renders T cells dysfunctional. The molecular mechanisms regulating this state of exhaustion are thought to be common in infection and cancer, despite obvious differences in their microenvironments. We discovered that NFAT5, an NFAT family member lacking an AP-1 docking site, is highly expressed in exhausted T cells from murine and human tumors and is a central player in tumor-induced exhaustion. While NFAT5 overexpression reduced tumor control, NFAT5 deletion improved tumor control by promoting the accumulation of tumor-specific CD8+ T cells that expressed less TOX and PD-1 and produced more cytokines particularly among precursor exhausted cells. Conversely, NFAT5 had no effect on chronic infection-induced T cell exhaustion. Mechanistically we found that TCR triggering induced NFAT5 expression and that hyperosmolarity stimulated transcriptional activity of NFAT5. We propose that NFAT5 takes over NFAT1/2 to promote exhaustion specifically in tumor-infiltrating CD8+ T cells.

immunology↗