Central nesfatin-1-expressing neurons are sensitive to peripheral inflammatory stimulus

Area of Science:

• Neuroscience
• Endocrinology
• Molecular Biology

Background:

• Nesfatin-1 is a newly identified protein with appetite-suppressing properties.
• It is expressed in both peripheral organs and specific brain regions involved in food intake regulation, such as the hypothalamus and brainstem.
• The role of nesfatin-1 in response to inflammatory signals remains largely unexplored.

Purpose of the Study:

• To investigate whether neurons activated by lipopolysaccharide (LPS), an endotoxin known to induce anorexia, express nesfatin-1.
• To determine if nesfatin-1 neurons in key brain areas are sensitive to peripheral inflammatory stimuli.
• To explore the potential contribution of nesfatin-1 to endotoxemic anorexia.

Main Methods:

• Double immunohistochemistry was employed to detect c-Fos (a marker of neuronal activation) and nesfatin-1 expression in rat brain sections.
• Quantitative analysis of co-localized c-Fos and nesfatin-1 positive neurons was performed in the paraventricular nucleus (PVN), supraoptic nucleus (SON), arcuate nucleus (ARC), and nucleus of the solitary tract (NTS).
• Triple labeling was used to identify catecholaminergic neurons (tyrosine hydroxylase-positive) co-expressing nesfatin-1 in the NTS.

Main Results:

• LPS administration significantly increased the number of c-Fos+/nesfatin-1+ neurons in the PVN, SON, and NTS.
• A less pronounced increase in c-Fos+/nesfatin-1+ neurons was observed in the ARC.
• A subset of LPS-activated nesfatin-1 neurons in the NTS were identified as catecholaminergic.

Conclusions:

• A portion of nesfatin-1 neurons in the hypothalamus and brainstem are responsive to peripheral inflammatory signals.
• These findings provide initial evidence that centrally released nesfatin-1 may play a role in the neural mechanisms underlying anorexia caused by endotoxemia.
• Nesfatin-1 neurons, particularly catecholaminergic ones in the NTS, are implicated in the body's response to inflammatory challenges affecting appetite.