Nuclear Factor B inducing kinase activation as a mechanism of pancreatic beta cell failure in obesity

The NF-B pathway is a master regulator of inflammatory processes and is implicated in insulin resistance and pancreatic beta cell dysfunction in the metabolic syndrome. While canonical NF-B signaling is well studied, there is little information on the divergent non-canonical NF-B pathway in the context of pancreatic islet dysfunction in diabetes. Here, we demonstrate that pharmacological activation of the non-canonical NF-B inducing kinase (NIK) disrupts glucose homeostasis in zebrafish in vivo. Further, we identify NIK as a critical negative regulator of beta cell function as pharmacological NIK activation results in impaired glucose-stimulated insulin secretion in mouse and human islets. NIK levels are elevated in pancreatic islets isolated from diet-induced obese (DIO) mice, which exhibit increased processing of non-canonical NF-B components p100 to p52, and accumulation of RelB. Tumor necrosis factor (TNF) and receptor activator of NF-B ligand (RANKL), two ligands associated with diabetes, induce NIK in islets. Mice with constitutive beta cell intrinsic NIK activation present impaired insulin secretion with DIO. NIK activation triggers the non-canonical NF-B transcriptional network to induce genes identified in human type 2 diabetes genome-wide association studies linked to beta cell failure. These studies reveal that NIK contributes a central mechanism for beta cell failure in diet-induced obesity.

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Malle EK, Zammit NW, Walters SN, Koay YC, Wu J, Tan BM, Villanueva JE, Brink R, Loudovaris T, Cantley J, McAlpine SR, Hesselson D, Grey ST