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Biology subjects

Prisco, F.

Publications and source records attributed to Prisco, F..

5 recordsLinked to original sources

Tet2-Clonal Hematopoiesis Promotes Whereas Dnmt3a-CH Inhibits Breast Cancer Progression During Aging

Clonal hematopoiesis of indeterminate potential (CHIP) driven by somatic mutations in blood cells increases with age and is associated with adverse outcomes in cancer patients. How CHIP mutations influence solid tumor progression remains unclear. Using inducible murine models of Dnmt3a- or Tet2-mutant CHIP combined with orthotopic syngeneic breast cancer models, we demonstrate that upon aging Dnmt3a-mutant CHIP prevents whereas Tet2-mutant CHIP drives breast cancer progression. Dnmt3a-mutant immune infiltrates established interferon-mediated MHCIIhigh tumor-associated macrophages (TAMs) that supported cytotoxic CD8+ T cell-mediated tumor rejection. In contrast, Tet2-mutant TAMs exhibited an inflammatory, immunosuppressive phenotype characterized by increased IL-1 and CXCL2 production, reduced MHCII expression, and impaired T cell recruitment and activation. Therapeutic blockade of IL-1R1 or CXCR2 reduced tumor progression in aged Tet2-mutant CHIP mice and partially restored anti-tumor immunity. These findings establish that the effects of CHIP on cancer are mutation- and age-dependent and identify IL-1/CXCL2-driven inflammation as a therapeutic vulnerability of tumor-promoting Tet2-mutant CHIP.

cancer biology↗

Astrocyte fatty acid uptake and ketogenesis in the mediobasal hypothalamus coordinate adaptive metabolic responses against high-fat diet exposure in male rodents

The mediobasal hypothalamus (MBH) constitutes a central regulator of energy homeostasis; specialized neurons in this region integrate peripheral metabolic signals to coordinate processes like food intake, energy expenditure or glucose homeostasis. While MBH neuronal dysfunction has been linked to obesity, increasing evidence indicates that astrocytes in this region are also active participants in the modulation of energy balance. MBH astrocyte ketone body signaling, in particular, has been proposed as an adaptive mechanism aimed at regulating energy homeostasis during dietary challenge. Here, we investigated the effects of MBH astrocytic lipid metabolism on the control of energy balance. We targeted distinct components of this pathway, ablating fatty acid (FA) transporter FATP4 in mice and knocking down 3-hydroxy-3-methylglutaryl-CoA lyase (HMGCL) in rats. MBH astrocyte FATP4 depletion markedly exacerbated high-fat diet (HFD)-induced obesity, increasing body weight and fat mass independently of food intake. Rather, this phenotype was driven by reduced energy expenditure and impaired brown adipose tissue oxidation. HMGCL knockdown in MBH astrocytes also promoted HFD-induced weight gain, not only through reduced energy expenditure but also through a transient hyperphagic response during early HFD exposure. In vitro studies in primary astrocyte cultures confirmed that disruption of FATP4 altered the expression of genes involved in mitochondrial lipid oxidation and ketogenesis. Similarly, HMGCL knockdown reduced the expression of monocarboxylate transporter MCT4, suggesting impaired astrocytic lactate and/or ketone body release. Together, these findings identify MBH astrocyte lipid metabolism as a critical component of the hypothalamic circuitry regulating energy balance, highlighting astrocytes as active contributors to the pathogenesis of obesity.

neuroscience↗

Tmem117, an oligodendrocyte-enriched regulator of NCX activity, links myelin homeostasis to counterregulation and metabolic health.

The counterregulatory response (CRR) to hypoglycemia is a fundamental, evolutionarily conserved homeostatic mechanism orchestrated by the central nervous system (CNS) to ensure survival during glucose scarcity. In individuals with diabetes, this response is frequently impaired, contributing to life-threatening episodes of hypoglycemia. Tmem117 was previously identified in a genetic screen as a promising hypothalamic regulator of CRR. Our previous work highlighted its contribution to CRR through regulation of vasopressin secretion. Here, we reveal that Tmem117 is also enriched in cells of the oligodendrocytic lineage and we characterize the contribution of oligodendrocytic Tmem117 in CRR. We show that depletion of Tmem117 from either all oligodendrocyte lineage cells or only mature oligodendrocytes leads to myelin deficits and male-specific defects in CRR. Furthermore, we reveal that transient, adult-onset depletion of Tmem117 in mature oligodendrocytes is sufficient to induce long-lasting metabolic imbalances in male mice, suggesting that defects in oligodendrocytes and myelin can affect peripheral glucose homeostasis. Mechanistically, we provide for the first-time insights on the function of Tmem117 showing that it regulates intracellular calcium dynamics through its interaction with the sodium-calcium exchanger NCX1. Together, these results redefine our understanding of the cellular contributors to the CRR, highlight the importance of oligodendrocytes in systemic glucose regulation, and position Tmem117 as a promising molecular target for cell-specific manipulation of NCX activity.

neuroscience↗

Monocyte-derived cells but not Microglia cause Oxidative Tissue Damage in Neuroinflammation

Multiple sclerosis (MS) is characterized by neuroinflammation, oxidative stress, iron toxicity and mitochondrial dysfunction. Reactive oxygen species (ROS) produced by mononuclear phagocytes (MPs) are widely held to drive tissue damage, yet the specific roles of central nervous system (CNS)- resident versus CNS-invading MPs remain unclear. Here, by combining single-cell profiling with conditional gene targeting, we systematically dissected and interfered with ROS production across CNS MPs in a preclinical model for neuroinflammation. We show that CNS-invading monocyte derived cells (MdCs) exhibit a higher oxidative stress gene signature and produce more ROS compared to CNS-resident microglia. While NADPH oxidase 2 (NOX2), a phagocytic source of ROS, proved redundant, our findings underscore the critical role of mitochondrial ROS (mtROS) in driving oxidative tissue damage. Quenching mtROS through mitocatalase overexpression in MdCs, but not microglia, significantly alleviated neuroinflammation in mice. Thus, our study resolves a longstanding controversy, identifying MdCs as the primary driver of ROS-mediated neuropathology.

immunology↗

Regulatory T cells control type 1-driven immunopathology restraining GM-CSF-producing helper T cells

Regulatory T (Treg) cells are critical for maintaining peripheral tolerance and preventing autoimmunity. Treg cell depletion or dysfunction rapidly results in fatal multiorgan inflammation linked to unrestrained effector T cell expansion, but the cytokine network underlying immunopathology, and its direct cellular mediators, remain elusive. Here, we combined gene targeting, fate-mapping tools, and high-dimensional cytometry to identify the T helper (TH) cell-derived cytokines and responding cells that execute inflammatory tissue damage upon global loss of peripheral tolerance in mice. We found that TH cell-derived GM-CSF, but not IL-17A, directed the ensuing immunopathology and thereby mortality through recruitment of tissue-invading phagocytes and granulocytes, and enhancement of their reactive oxygen species production and phagocytic proficiency. Our study highlights the critical role of Treg cells in controlling GM-CSF- producing TH cells and type 1-responses to restrain phagocyte-mediated tissue destruction and provides a framework for the use of anti-GM-CSF therapies in patients with chronic inflammatory disorders.

immunology↗