Current research indicates that insulin secretion deficiency in β-cells contributes to Type 2 diabetes mellitus (T2DM), which is associated with neuropeptide Y 1 receptor (Npy1r) overexpression from neuropeptide Y (NPY) system dysregulation. To date, limited literature has explored nobiletin (NOB) as a circadian modulator for restoring β-cell function through Npy1r regulation. This study investigates NOB's stimulatory effects on insulin secretion via Npy1r and clock-modulatory signaling to elucidate its underlying mechanism. The findings demonstrated that NOB ameliorated hyperglycemia and promoted insulin secretion in two distinct mouse models: T2DM induced by a high-fat diet with low-dose streptozotocin, and acute hyperglycemia triggered by NPY. Moreover, NOB reduced NPY family peptides in the serum and suppressed Npy1r overexpression in β-cells. Comprehensive investigations revealed that NOB mitigated Npy1r-mediated β-cell dysfunction through activating clock-modulatory signaling, evidenced by restored Bmal1::Luc bioluminescence rhythmicity in mouse insulinoma6 (MIN6) cells. Molecular docking confirmed a direct NOB-Npy1r interaction, while mechanistic analyses demonstrated modulation of the retinoic acid-related orphan receptors (RORs)/Bmal1-Yes-associated protein (Yap) pathway via Yap suppression and Bmal1 activation, based on the interventions with palmitic acid, BMS 193885 (Npy1r antagonist), and NPY. Therefore, this study provides evidence that NOB can protect β-cells from insulin secretion dysfunction by downregulating Npy1r expression and activating the RORs/Bmal1-Yap pathway.
Xiaowen Li,Ruikang Guo,Lingling Liang,Hao Liang,Guangqi Zhou,Qinglan Lu,Yonghui Huang,Zhen Qi,Xiaojie Li
Objective: Periodontitis, a prevalent oral disease leading to alveolar bone defects, remains a primary cause of tooth loss in adults. The biologic mechanisms driving bone loss in periodontitis are still poorly understood, limiting the development of genetic treatment. This study investigates potential therapeutic targets for alveolar bone loss by analyzing transcriptomic data related to the osteogenic differentiation of induced pluripotent stem cells (iPSCs). Methods: Using in vitro and in vivo models, we examined the role of neuropeptide Y receptor Y1 (NPY1R) and the PI3K-AKT-mTOR (PAM) signaling pathway in osteogenic differentiation and bone loss. A combination of bioinformatics, molecular biology, and histologic techniques was employed to pinpoint key signaling events that influence bone remodeling in periodontitis and to identify potential intervention points. Results: Transcriptomic profiling during iPSC osteogenic differentiation revealed significant upregulation of neuropeptide Y (NPY) and NPY1R. Suppression of NPY1R reduced the osteogenic capacity of iPSCs. Activation of the PAM pathway was observed during osteogenesis, and treatment with LY294002, a PAM pathway inhibitor, led to decreased osteogenic activity. In vivo experiments using a rat periodontitis model confirmed increased expression of NPY1R and activation of the PAM pathway, suggesting a role in bone repair processes. Conclusion: The NPY/NPY1R axis and the PAM signaling pathway appear to regulate bone regeneration and may be involved in preventing alveolar bone loss in periodontitis. These findings provide a new direction for therapy targeting bone defects associated with periodontal disease.
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