ZiBuPiYin recipe mediates BDNF/TrkB/CREB regulation of synaptic plasticity: Key role of SYT1 acetylation modification.

ETHNOPHARMACOLOGICAL RELEVANCE: ZiBuPiYin recipe (ZBPYR) has been verified to ameliorate insulin resistance, alleviate neuroinflammation, mitigate oxidative stress, and remodel gut microbiota in type 2 diabetes mellitus (T2DM) rats, thereby exerting definite therapeutic efficacy against diabetes-associated cognitive decline (DACD). As the core preventive doctrine of traditional Chinese medicine (TCM), "Zhi-wei-bing" (in Chinese) emphasizes early intervention to block the progression of pathological lesions. Nevertheless, the specific molecular mechanism responsible for the "Zhi-wei-bing" intervention effects of ZBPYR against DACD remains unclear. AIM OF THE STUDY: Based on the early intervention and disease-blocking core philosophy of "Zhi-wei-bing", this study designed two intervention timepoints in genetically susceptible ZDF rats to compare the differential effects of ZBPYR at the pre-phenotypic stage and post-phenotypic stage of T2DM, aiming to compare and verify the intervention efficacy of ZBPYR at different stages of DACD, and focusing on the Synaptotagmin I (SYT1) acetylation mediated brain-derived neurotrophic factor (BDNF)/tyrosine receptor kinase B (TrkB)/cAMP response element binding (CREB) signaling pathway in the regulation of synaptic plasticity, so as to experimentally interpret the scientific implication of the TCM doctrine of "Zhi-wei-bing". MATERIALS AND METHODS: Spontaneous T2DM model ZDF rats and high-glucose induced PC12 cells were used to evaluate the preventive and therapeutic effects of ZBPYR. Metabolic phenotypes and cognitive behaviors were comprehensively detected. Acetylation-modified proteomics was used to screen key acetylated proteins. Combined with Nissl staining, Golgi staining, immunofluorescence, flow cytometry, western blotting, co-immunoprecipitation and thermal shift assay, hippocampal acetylation modification, neuronal pathology, synaptic structure and function, and BDNF/TrkB/CREB signaling pathway were systematically analyzed. CONCLUSION: Early intervention with ZBPYR up-regulated the acetylation level of SYT1 at K9 site, promoted the specific binding of acetylated SYT1 and BDNF, activated BDNF/TrkB/CREB signaling pathway, regulated synaptic plasticity, delayed the progression of T2DM phenotype, restored learning and memory impairment, and played the role in preventing and treating DACD. The current work provided a new strategy for the systematic application of TCM in "Zhi-wei-bing" of DACD, and a theoretical basis for the clinical application of ZBPYR.