Biology subjects

Nadjar, A.

Publications and source records attributed to Nadjar, A..

3 recordsLinked to original sources

bioRxiv2026

A Female-Specific Microglial Redox Program Gates Susceptibility to Obesity

Chronic consumption of energy-dense, high-fat foods persistently exposes hypothalamic circuits that govern body weight to nutrient excess, progressively altering their activity and thereby promoting obesity. Microglia, the brain resident immune cells, sense circulating lipids, but how their intracellular metabolic programs adapt to chronic dietary excess, and how this contributes to obesity risk, is unclear. Here, we reveal a sex-dependent control of calorie overload by hypothalamic microglial cells. In females, but not males, microglia engage a protective metabolic program with increased antioxidant capacity and mitochondrial network remodeling, conferring resistance to early weight gain. Over time, activation of mTORC1 signaling in microglia disrupts mitochondrial functions and dismantles this transient resilience, culminating in weight gain. These findings identify microglial mTORC1 as a sex-specific switch between resilience and vulnerability to obesity and position microglial metabolism as a tractable target for sex-informed weight control.

neuroscience↗

bioRxiv2024

Long-term disruption of glucose homeostasis in a rodent model of preterm birth.

Around 1 of every 10 babies is born preterm, and the incidence of preterm birth has been rising. The long-term consequences of preterm survivors are not fully understood. Preterm birth is proven to be associated with metabolic diseases and related disorders later in life. Preterm newborns are susceptible to perinatal inflammatory events such as chorioamnionitis, hypoxia-ischemia, and sepsis. We hypothesized that perinatal inflammation has a role in the developmental programming of metabolic diseases and related disorders. In the present study, perinatal inflammation was modeled by systemic administration of IL-1{beta} in mice. We observed a pronounced sexual dimorphism where only the males presented significant insulin resistance and glucose intolerance accompanied by leptin resistance in the long term following perinatal inflammation exposure. Adiposity and energy homeostasis were intact. It showed that perinatal inflammation selectively contributes to the long-term dysregulation of glucose metabolism in a sex-dependent manner. The underlying mechanism might be linked with hypothalamic inflammation and upregulated circulating CCL5. Metformin treatment might be optional to treat insulin resistance resulting from perinatal inflammation. HighlightsO_LIPerinatal inflammation is common in preterm infants, often leading to perinatal brain injuries. However, the long-term metabolic outcomes of these infants are not fully revealed. C_LIO_LIWe explored the long-term metabolic outcomes in mice with perinatal IL-1{beta} exposure and sought its association with inflammation. C_LIO_LIPerinatal inflammation has a profound and deleterious role in glucose metabolism in a sex-dependent and time-dependent manner. C_LIO_LIPerinatal inflammation might be a risk factor for metabolic disorders in preterm survivors. C_LI

physiology↗

bioRxiv2019

Essential omega-3 fatty acids tune microglial phagocytosis of synaptic elements in the developing brain

Omega-3 fatty acids (n-3 polyunsaturated fatty acids; n-3 PUFAs) are essential for the functional maturation of the brain. Westernization of dietary habits in both developed and developing countries is accompanied by a progressive reduction in dietary intake of n-3 PUFAs. Low maternal intake of n-3 PUFAs has been linked to neurodevelopmental diseases in epidemiological studies, but the mechanisms by which a n-3 PUFA dietary imbalance affects CNS development are poorly understood. Active microglial engulfment of synaptic elements is an important process for normal brain development and altered synapse refinement is a hallmark of several neurodevelopmental disorders. Here, we identify a molecular mechanism for detrimental effects of low maternal n-3 PUFA intake on hippocampal development. Our results show that maternal dietary n-3 PUFA deficiency increases microglial phagocytosis of synaptic elements in the developing hippocampus, through the activation of 12/15- lipoxygenase (LOX)/12-HETE signaling, which alters neuronal morphology and affects cognition in the postnatal offspring. While women of child bearing age are at higher risk of dietary n-3 PUFA deficiency, these findings provide new insights into the mechanisms linking maternal nutrition to neurodevelopmental disorders.\n\nOne Sentence SummaryLow maternal omega-3 fatty acids intake impairs microglia-mediated synaptic refinement via 12-HETE pathway in the developing brain.

neuroscience↗