Biology subjects

Severi, I.

Publications and source records attributed to Severi, I..

4 recordsLinked to original sources

bioRxiv2026

Ciliary neurotrophic factor curbs palmitate-induced inflammatory and metabolic changes in NPY/AgRP hypothalamic neurons

Introduction: In both humans and experimental animals, obesity is associated with hypothalamic inflammation and neuronal metabolic dysfunction, which contribute to disrupting body energy homeostasis. Although ciliary neurotrophic factor (CNTF) is a neuroprotective cytokine with recognized anti-obesity effects in peripheral metabolic tissues, its role in obesity-associated hypothalamic dysfunction is still poorly characterized. We investigated whether CNTF exerts any direct effects on mHypoE-N41 (N41) hypothalamic neurons and whether it modulates the effects induced by palmitate (PA), an established model of obesity-associated neuronal metabolic dysfunction. Methods: N41 cells were administered CNTF alone or combined with PA to assess whether CNTF affects PA-induced lipotoxic stress. Gene and protein expression was assessed by qRT-PCR, western blotting, and immunofluorescence analysis. Results: In N41 cells, CNTF activated the STAT3, ERK and AMPK signaling pathways. It also upregulated genes involved in mitochondrial metabolism and fatty acid oxidation, including Ucp2, Cpt1 and Pgc1, as well as the proliferation-associated markers Ki-67 and PCNA. PA treatment induced inflammatory and endoplasmic reticulum stress responses and impaired insulin signaling. In PA-treated N41 cells, CNTF significantly attenuated the expression of pro-inflammatory markers Tnf, Mcp1 and Nfkb, restored insulin-induced AKT phosphorylation, and partially reversed PA-induced changes in the expression of metabolic genes Ucp2 and Cpt1. Conclusions: Collectively, these findings indicate that CNTF exerts direct protective metabolic effects on hypothalamic N41 neurons subjected to lipotoxic stress and supports a role for it in the preservation of neuronal metabolic function under obesogenic conditions.

molecular biology↗

bioRxiv2026

Plasma oxytocin measured by LC-MS/MS varies with life stage, sex, and obesity in mice

ObjectiveOxytocin (Oxt) assessment in plasma is challenging, and available data are contradictory. We aimed to assess circulating Oxt in mice by a validated nano-liquid chromatography/mass-spectrometry (nLC-MS/MS) protocol, combined with Oxt hypothalamic expression in different sex, life stages, and in diet-induced obesity. MethodsWe assessed plasma Oxt by nLC-MS/MS, Oxt hypothalamic expression by qPCR, and Oxt-immunoreactive neuron and fiber densities by immunohistochemistry and morphometric analyses in C57BL/6 mice at 21 and 60 days of life (p21 and p60, respectively). Mice in normo-fed condition and following 12 weeks of high-fat diet (HFD) were studied alongside food intake and hypothalamic expression of its regulators. ResultsCirculating Oxt does not vary based on sex at p21 and p60 but increases with aging. While hypothalamic Oxt mRNA expression followed the same trend across both sexes, Oxt neuron and fiber densities exhibited a similar trend only in females. Plasma vasopressin (Avp) followed Oxt trend in females but was opposite in males and was not mirrored by Avp mRNA hypothalamic expression. HFD-fed females were more resistant to weight gain compared to males and displayed higher Oxt plasma levels and hypothalamic expression. Sex dimorphism in food intake and hypothalamic expression of Avp and of key anorexigenic and orexigenic neuropeptides was detected. ConclusionsOxt plasma levels are higher in adulthood compared to weaning in mice of both sexes who displayed similar concentrations. Oxt plasma levels are mirrored by Oxt hypothalamic expression. In obesity, females display a lower increase in body weight but higher Oxt plasma levels than males. SignificanceThis study delineates the pattern of Oxt plasma levels across various age, sex and in obesity in mice. We overcome some limitations of previous research, which were often confounded by numerous factors, by reliably measuring circulating Oxt and integrating this with parallel analyses of Oxt gene expression, and Oxt neuron and immunoreactive fiber densities. Critically, this is among the few studies to employ LC-MS/MS specifically in mice. This novel, integrated perspective is relevant given the compelling evidence for Oxts role as an anti-obesity agent and its potential as a therapeutic target. A precise understanding of Oxt regulation in different conditions, backed by reliable methodologies, is indispensable for the rational development of effective treatments for obesity and related endocrine diseases.

neuroscience↗

bioRxiv2026

The ciliary neurotrophic factor induces Stat3 phosphorylation in distinctive cytotypes of organs involved in body metabolism: an immunohistochemical study

Administration of ciliary neurotrophic factor (CNTF) reduces food intake and body weight in both humans and experimental animals, where it also ameliorates hyperglycemia, hyperinsulinemia, and dyslipidemia. To exert its anti-obesogenic and anti-diabetogenic effects, CNTF targets brain feeding centers as well as multiple peripheral organs inducing the phosphorylation of the transcription factor signal transducer and activator of transcription 3 (p-STAT3). However, data showing which peripheral cytotypes are specifically targeted by exogenous CNTF in vivo in metabolically relevant organs are currently lacking. Here, we first evaluated the gene expression levels of the subunits of the tripartite CNTF receptor (Cntfr) complex, i.e., the Cntfr, the leukemia inhibitory factor receptor {beta} (Lifr{beta}) and the glycoprotein 130 (gp130), by quantitative real-time PCR in metabolically relevant organs of adult male mice: gastrointestinal (GI) tract, pancreas, liver, visceral and subcutaneous white (WAT) and interscapular brown adipose tissue (iBAT), skeletal muscle and the sciatic nerve. We then quantified p-STAT3 by Western blotting in these organs after intraperitoneal administration of CNTF (0.3 mg/kg) or saline. Finally, we mapped CNTF-responsive cells by immunohistochemistry, followed by morphometric quantification and confocal microscopy in both CNTF- and saline-treated mice. Lifr{beta} and gp130 were ubiquitously detected across all the investigated organs; the Cntfr showed the highest expression levels in the skeletal muscle, sciatic nerve, and iBAT, whereas it was found to be expressed to a lesser extent in the other sites. Administration of CNTF led to a significant increase of p-STAT3/STAT3 protein ratio in all organs examined, except the duodenum, and induced a distinctive pattern of cell nuclear p-STAT3 immunoreactivity. Notably, along the analyzed GI tract CNTF induced nuclear STAT3 phosphorylation in neurons of the submucosal and myenteric plexuses of the enteric nervous system and in contractile cells of the muscularis externa, where the response peaked in the mesenteric gut and colon. In the pancreas, CNTF triggered a higher activation within the endocrine component compared to the exocrine parenchyma. In the liver, CNTF induced STAT3 phosphorylation not only in parenchymal cells but also in sinusoids and resident macrophages. The cytokine activated p-STAT3 in subcutaneous and visceral white adipocytes, but also in brown adipocytes, with a prominent response observed in the beige subcutaneous adipocytes; adipose resident macrophages and endothelial cells of numerous blood vessels were also CNTF-responsive. Lastly, in skeletal muscle, a major site for glucose/lipid utilization, CNTF induced widespread nuclear p-STAT3 immunoreactivity in muscle fibers and in connective and Schwann cells of the peripheral nerves, including the sciatic nerve, supplying the gastrocnemius. In conclusion, our data indicate that CNTF acts across diverse cytotypes within metabolically relevant organs and tissues, likely fostering its peripheral metabolic effects through this cellular heterogeneity.

cell biology↗

bioRxiv2020

The Epidermal Barrier is Indispensable for Systemic Energy Homeostasis

ObjectivesHomeostatic regulation of body temperature is fundamental to mammalian physiology and is controlled by acute and chronic responses of local, endocrine and neuronal regulators. Although the skin is the largest sensory organ of the human body, and plays a fundamental role in regulating body temperature, it is surprising that adaptive alterations in skin functions and morphology only vaguely have been associated with physiological responses to cold stress or sensation of ambient temperatures. MethodsTo unravel the physiological responses to a compromised epidermal barrier in detail we have used animal models with either defects in skin lipid metabolism (ACBP-/- and skin-specific ACBP-/- knockout mice) or defects in skin structural proteins (ma/ma Flgft/ft). The primary objective was to clarify how defects in epidermal barrier function affect 1) energy expenditure by indirect calorimetry, 2) response to high fat feeding and a high oral glucose load and 3) expression of brown-selective gene programs by quantitative PCR in inguinal WAT (iWAT). ResultsWe show that mice with a compromised epidermal barrier function exhibit increased energy expenditure, increased food intake, browning of the iWAT, and resistance to diet-induced obesity. The metabolic phenotype, including browning of the iWAT, is reversed by housing the mice at thermoneutrality (30{degrees}C) or by pharmacological {beta}-adrenergic blocking. These findings show that a compromised epidermal barrier induces a {beta}-adrenergic response that increases energy expenditure and browning of the white adipose tissue to maintain a normal body temperature. ConclusionOur findings show that the epidermal barrier plays a key role in maintaining systemic metabolic homeostasis. HighlightsEnergy expenditure is significantly augmented in mice with impaired epidermal barrier. Mice with compromised barrier display increased food intake while maintaining normal bodyweight. Mice with an impaired epidermal barrier are resistant to diet-induced obesity and insulin resistance. Compromised barrier function induces expression of brown-selective gene programs in iWAT. Thermoneutral housing or blocking {beta}-adrenergic signaling prevents induction of brite-selective genes in iWAT and reverses food intake.

biochemistry↗