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DeBerge, M.

Publications and source records attributed to DeBerge, M..

4 recordsLinked to original sources

Oligodendrocyte stress response as a driver of vascular dementia

Vascular dementia (VaD) is a prevalent and devastating neurocognitive disorder characterized by profound white matter damage, yet the precise cellular mechanisms linking cerebrovascular stress to demyelination remain poorly understood. Here, we characterize the impact of a chronic cardiometabolic stress regimen combining a high-fat diet and hypertension (HF/HBP) on central nervous system structure and function. Adult HF/HBP mice exhibit progressive oligodendroglial cell loss and myelin thinning, followed by cognitive impairments, anxiety-like behavior, and memory deficits that recapitulate clinical features of VaD. Mechanistically, we identify the integrated stress response (ISR) as a central driver of this pathology; pharmacological inhibition of the ISR restores myelination, while cell-specific genetic deletion of the ISR-activating kinase PERK from oligodendrocytes fully protects mice from HF/HBP-induced pathological and behavioral defects. Furthermore, we provide translational evidence that the ISR is activated in oligodendrocytes in human cases of cerebrovascular disease. Together, these findings reveal a critical, cell-autonomous role for oligodendroglial ISR activation during cerebrovascular stress and position this pathway as a viable therapeutic target to mitigate VaD pathogenesis.

neuroscience↗

The Neonatal Myeloid Hypoxia Response Promotes a Cardiac Regenerative Response through Insulin-Like Growth Factor

BackgroundThe adult mammalian heart lacks the regenerative potential required to replenish depleted cardiomyocytes and restore cardiac function after injury. Ischemic cardiac injury contributes to heart failure, a leading cause of death worldwide. Neonatal mice possess the capacity to regenerate injured myocardium and macrophages contribute to this process. The mechanisms contributing to the regenerative crosstalk between macrophages and cardiomyocytes remain incompletely elucidated and offer potential to inform future therapeutic strategies. MethodsTo test the immune contribution during cardiac regeneration, we studied the response to myocardial ischemia in neonatal mice after silencing myeloid hypoxia inducible factor 1 (Hif1) and reconstituting HIF-dependent mitogens. In parallel, we examined epigenetic and transcriptional signatures of the cardiac macrophage response and focused on intercellular crosstalk with cardiomyocytes. ResultsIn myeloid Hif1 deficient mice, cardiac regenerative function was lost after coronary ligation. This manifested through loss of ventricular systolic function and elevated myocardial scarring. HIF1 was found to be activated in resident-type cardiac macrophages after ischemic insult. Hypoxia stimulated macrophages to secrete insulin-like growth factor 1 (IGF-1), and this required Hif1. Parallel multiomic analysis revealed epigenetic regenerative signatures. ConclusionsThe data reveal an age-restricted requirement for myeloid Hif1 in neonatal cardiac regeneration, likely through IGF-1 signaling.

immunology↗

Microglial metabolic reprogramming drives cognitive decline in heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is a rapidly growing public health concern and an emerging contributor to dementia, yet the mechanisms linking cardiometabolic dysfunction to neurodegeneration remain poorly understood. Here, we demonstrate that HFpEF drives a sustained neuroinflammatory state through microglial metabolic reprogramming. Using a clinically relevant murine model of HFpEF, we identified robust induction of HIF-1 signaling in microglia via integrated transcriptomics and metabolomics, coupled with increased glycolytic metabolism revealed by extracellular flux analysis. Conditional deletion of Hif1a in microglia during HFpEF attenuated neuroinflammation, preserved white matter integrity, and rescued cognitive performance. We further identify Sema4D as a HIF-1-dependent, microglia-derived effector linking metabolic stress to white matter injury. These findings establish a mechanistic bridge between cardiovascular disease and cognitive dysfunction and reveal microglial HIF-1 signaling as a tractable therapeutic strategy for preventing cognitive decline in cardiometabolic disease.

immunology↗

Bone Marrow-Derived AXL Tyrosine Kinase Promotes Mitogenic Crosstalk and Cardiac Allograft Vasculopathy

Cardiac Allograft Vasculopathy (CAV) is a leading contributor to late transplant rejection. Although implicated, the mechanisms by which bone marrow-derived cells promote CAV remain unclear. Emerging evidence implicates the cell surface receptor tyrosine kinase AXL to be elevated in rejecting human allografts. AXL protein is found on multiple cell types, including bone marrow-derived myeloid cells. The causal role of AXL from this compartment and during transplant is largely unknown. This is important because AXL is a key regulator of myeloid inflammation. Utilizing experimental chimeras deficient in the bone marrow-derived Axl gene, we report that Axl antagonizes cardiac allograft survival and promotes CAV. Flow cytometric and histologic analyses of Axl-deficient transplant recipients revealed reductions in both allograft immune cell accumulation and vascular intimal thickness. Co-culture experiments designed to identify cell-intrinsic functions of Axl uncovered complementary cell-proliferative pathways by which Axl promotes CAV-associated inflammation. Specifically, Axl-deficient myeloid cells were less efficient at increasing the replication of both antigen-specific T cells and vascular smooth muscle cells (VSMCs), the latter a key hallmark of CAV. For the latter, we discovered that Axl-was required to amass the VSMC mitogen Platelet-Derived Growth Factor. Taken together, our studies reveal a new role for myeloid Axl in the progression of CAV and mitogenic crosstalk. Inhibition of AXL-protein, in combination with current standards of care, is a candidate strategy to prolong cardiac allograft survival.

immunology↗