bims-minfam 2025-01-05 papers

Nat Aging. 2025 Jan 02.

Restoring aging-related tissue homeostasis via reactivated innate immunotherapy.

DOI: https://doi.org/10.1038/s43587-024-00782-1

Nat Aging. 2025 Jan 02.

Chronic stress induces senescence build-up early in life.

Victor Lau, Ifeoluwa Awogbindin, Marie-Ève Tremblay.

DOI: https://doi.org/10.1038/s43587-024-00774-1

Front Cell Neurosci. 2024 ;18 1487867

Tet2-mediated clonal hematopoiesis modestly improves neurological deficits and is associated with inflammation resolution in the subacute phase of experimental stroke.

Megan A Evans, Nicholas W Chavkin, Soichi Sano, Hanna Sun, Taneesha Sardana, Ramya Ravi, Heather Doviak, Ying Wang, Yoshimitsu Yura, Ariel H Polizio, Keita Horitani, Hayato Ogawa, Karen K Hirschi, Kenneth Walsh.

Introduction: Recent work has revealed that clonal hematopoiesis (CH) is associated with a higher risk of numerous age-related diseases, including ischemic stroke, however little is known about whether it influences stroke outcome independent of its widespread effects on cardiovascular disease. Studies suggest that leukocytes carrying CH driver mutations have an enhanced inflammatory profile, which could conceivably exacerbate brain injury after a stroke.
Methods: Using a competitive bone marrow transplant model of Tet2-mediated CH, we tested the hypothesis that CH would lead to a poorer outcome after ischemic stroke by augmenting brain inflammation. Stroke was induced in mice by middle cerebral artery occlusion and neurological outcome was assessed at acute (24 h) and subacute (14 d) timepoints. Brains were collected at both time points for histological, immunofluorescence and gene expression assays.
Results: Unexpectedly, Tet2-mediated CH had no effect on acute stroke outcome but led to a reduction in neurological deficits during the subacute phase. This improved neurological outcome was associated with lower levels of brain inflammation as evidenced by lower transcript levels of various inflammatory molecules alongside reduced astrogliosis.
Discussion: These findings suggest that Tet2-mediated CH may have beneficial effects on outcome after stroke, contrasting with the conventional understanding of CH whereby leukocytes with driver mutations promote disease by exacerbating inflammation.

Keywords: CHIP; TET2; cerebral ischemia; inflammation; ischemic stroke; mouse

DOI: https://doi.org/10.3389/fncel.2024.1487867

J Clin Invest. 2025 Jan 02. pii: e187529. [Epub ahead of print]135(1):

Clonal hematopoiesis JAKs up plaque formation.

Koral Campbell, Qing Li.

Clonal hematopoiesis (CH) is a condition in which hematopoietic stem cells (HSCs) acquire mutations seen in leukemia. While individuals with CH generally do not show signs of hematologic disease, the condition becomes more common with age and correlates with age-related diseases, especially cardiovascular disease (CVD). JAK2 mutations in HSCs can lead to CH and correlate with atherosclerosis, but the condition has been difficult to study because of challenges modeling the mutant cells at very low frequency. In this issue of the JCI, Liu et al. developed a low-allele-burden (LAB) mouse model in which a small number of bone marrow cells carrying the Jak2VF mutation were transplanted into mice predisposed to hyperlipidemia. Along with recapitulating features of plaque development, the authors identified the phagocytic receptors MERTK and TREM2 in WT cells as downstream of the inflammatory cytokine IL-1. These findings provide potential targets for preventing or treating patients at risk for CH-associated CVD.

DOI: https://doi.org/10.1172/JCI187529