The anorexigenic peptide nesfatin-1 dampens the B cell response to receptor mediated stimulation through inhibition of NFĸB signaling.

Abstract

Nesfatin-1, a post translational product of the protein encoded by the nucleobindin 2 gene (NUCB2), was functionally identified as an appetite regulatory molecule in rat hypothalamic nuclei. In the years following the discovery, those findings have been corroborated and expanded upon, and we now know that nesfatin-1 is expressed throughout peripheral tissues and exerts physiological effects beyond feeding control. Literature indicates that adipose tissue is one of the peripheral sources of NUCB2/nesfatin-1, and in this setting, it has anti-inflammatory effects that have recently been implicated in regulating chronic inflammation associated with diet induced obesity. Currently, there are gaps in our understanding of what cell types within the adipose tissue compartment respond to nesfatin-1, in addition to the cellular mechanism(s) of this peptide. In this study, we sought to determine a mechanism by which this peptide might directly interact with the immune system starting with a human B cell line, Raji. We show that nesfatin-1 inhibits lipopolysaccharide (LPS) and B cell receptor (BCR) dual stimulation-mediated B cell growth, stimulation induced cell death, and secretion of inflammatory mediators. Specifically, there was a reduced fold-change in B cell growth during stimulation which is paired with a reduction in the formation of apoptotic (annexin V⁺) cells. Additionally, nesfatin-1 significantly reduced IgM secretion and modestly reduced TNFα secretion by stimulated B cells. The anti-inflammatory effects of nesfatin- 1 overall are likely due to attenuation of NFĸB signaling, via inhibition of IĸB degradation, in stimulated B cells.