Biology subjects

Gavini, C.

Publications and source records attributed to Gavini, C..

5 recordsLinked to original sources

bioRxiv2025

Tanycyte-mediated synapse pruning shapes hypothalamic circuits controlling metabolism.

Synaptic pruning by glial cells is critical for refining neural circuits, yet which glial populations mediate this process in hypothalamic networks controlling energy balance remains poorly understood. Here, using 3D-ultrastructural analyses and molecular approaches, we show that tanycytes --specialized glial cells lining the third ventricle-- actively engulf excitatory synapses in the mediobasal hypothalamus during a defined postnatal window. This phagocytic activity relies on tanycytic MFG-E8 and phosphatidylserine exposure on synaptic elements. Disruption of this pathway reduces synapse uptake in vitro and alters body weight control around weaning and glucose homeostasis in adulthood. These findings identify tanycytes as previously unrecognized glial mediators of synaptic pruning in hypothalamic circuits, establishing their active role in shaping neural networks underlying energy balance.

neuroscience↗

bioRxiv2025

Tanycytic annexinA1-containing extracellular vesicles control thermogenesis by orchestrating microglial and neuronal functions.

Obesity, a major global health issue, results from disrupted energy balance driven by chronic hypothalamic inflammation and altered intercellular communication. Among the diverse cells orchestrating this regulation, tanycytes--specialized ependymal cells at the brain-blood interface--have emerged as key modulators, yet the molecular mechanisms by which they influence surrounding cells remain poorly understood. Here, we identify Annexin A1 (ANXA1) as a tanycyte-derived anti-inflammatory signal whose expression, localization, and secretion are dynamically regulated by nutritional state and altered under high-fat diet. During positive energy balance, ANXA1 is secreted in CD9 extracellular vesicles (EV), remodeling hypothalamic networks by altering microglial morphology, synaptic density, and neuronal activation. These EV-mediated effects extend systemically to regulate brown adipose tissue thermogenesis, glucose homeostasis, and overall energy balance. Our findings reveal a previously unrecognized tanycyte-microglia-neuron signaling axis and highlight EV-mediated glial communication as a potential therapeutic target in obesity-associated neuroinflammation.

neuroscience↗

bioRxiv2021

LXR agonist Prevents Peripheral Neuropathy and modifies PNS immune cells in Aged Mice

Peripheral neuropathy is a common and progressive disorder in the elderly that interferes with daily activities and increases the risk of injury. It is of importance to find efficient treatments to treat or delay this age-related neurodegeneration. We previously demonstrated that activation of the cholesterol sensor Liver X receptor (LXR) with the potent agonist GW3965, alleviates pain in a diet-induced obesity model. Because cholesterol had also been linked to neuropathy during aging, we sought to test whether LXR activation may improve neuropathy and pain in aged mice by treating 21-month-old mice for 3 months with GW3965. Treatment resulted in a significant increase in nerve fibers of the sub-basal plexus, accompanied by a change in polarization, metabolism, and cholesterol content of macrophages in the sciatic nerve. These results suggest that activation of the LXR may block the progression of neuropathy associated with aging by modifying nerve-immune cell cholesterol, thereby providing new pathways to target in efforts to delay neuropathy during aging.

neuroscience↗

bioRxiv2021

Live Monitoring of Inflammation Reveals Tissue and Sex-specific Responses to Western Diet and Butyrate treatment

Obesity is a current epidemic, affecting millions of individuals worldwide. Chronic obesity is characterized by a low-grade systemic inflammation besides not being a classic inflammatory disease. Many studies have tried to identify inflammatory insults dysregulated by a Westernized diet - consisted of high fat, high sucrose, and high cholesterol -mainly focusing on production and secretion of inflammatory cytokines. The gut microbiome and derived metabolites, including the short-chain fatty acid butyrate, have received increased attention as underlying some of the obesogenic features. In the present work, we utilized a novel biosensor mouse model capable of monitoring in vivo inflammation. We observed tissue- and sex- specific caspase-1 activation patterns in obese mice and treated with butyrate. Our work utilizing a caspase-1 biosensor mouse model, flow cytometry and computational analyses and offers new mechanistic insights underlying the effect of butyrate in obesity and its complications.

neuroscience↗

bioRxiv2020

Neuronal LXR Regulates Neuregulin-1 Expression and Sciatic Nerve-Associated Cell signaling

Neuropathic pain caused by peripheral nerve injury significantly affects sensory perception and quality of life. Accumulating evidence strongly link cholesterol and inflammation with development and progression of Obesity and Diabetes associated-neuropathies. However, the exact mechanisms of how lipid metabolism in peripheral nervous system (PNS) contributes to the pathogenesis of neuropathy remains poorly understood. Dysregulation of LXR pathways have been identified in many transcriptomic analyses in neuropathy models. LXR /{beta} expressed in sensory neurons are necessary for proper peripheral nerve function. Deletion of LXR /{beta} from sensory neurons lead to pain-like behaviors. In this study, we identified that LXR /{beta} expressed in sensory neurons regulates neuronal neuregulin-1 (Nrg1). Using in vivo cell-specific approaches, we observed that loss of LXR from sensory neurons altered genes regulating lipid metabolism in non-neuronal cells potentially representing Schwann cells (SC). Our data suggest that neuronal LXR may regulates SC function via a Nrg1-dependent mechanism. The decrease in Nrg1 expression in DRG neurons of WD-fed mice may suggest an altered Nrg1-dependent neuron-SC communication in Obesity. The communication between neurons and non-neuronal cell such as SC could be a new biological pathway to study and to treat Obesity-associated neuropathy and PNS dysfunction.

neuroscience↗