Acta Biochimica et Biophysica Sinica•2025•DOI: 10.3724/abbs.2025070
Schisandrin A (SchA), a bioactive lignan that was isolated from the dried fruit of Schisandra chinensis, has attracted much attention because of its diverse spectrum of pharmacological effects. The aim of this study is to clarify the function of SchA in diabetes-related fear memory impairment and its molecular mechanisms. Rats are randomly assigned to 4 groups: the control group (Con group), the DM group, the DM + SchA group, and the Con + SchA group. The results demonstrate that SchA treatment improves insulin sensitivity, reduces blood glucose, and significantly reduces memory impairment. SchA treatment also prevents histological damage, enhances synaptic protein production, and significantly decreases Aβ42 formation in the diabetic prefrontal cortex. Further research reveals that SchA therapy decreases microglial activation and the expression levels of variables linked to inflammation while increasing the phosphorylation of proteins implicated in the insulin resistance signaling pathway. Furthermore, in the prefrontal cortex of diabetic rats, SchA decreases ferroptosis by increasing the protein expressions of GPX4, SLC7A11, Nrf2, HO-1, and SIRT1. Overall, our findings suggest that SchA may lessen diabetes-associated fear memory impairment symptoms by, most likely, lowering ferroptosis and inflammatory responses in the prefrontal brain of diabetic rats. SchA may be a useful therapy for diabetes, including memory impairment.
Acta Biochimica et Biophysica Sinica•2024•DOI: 10.3724/abbs.2024086
Endothelial dysfunction (ED) serves as the pathological basis for various cardiovascular diseases. Guanosine triphosphate cyclopyrrolone 1 (GCH1) emerges as a pivotal protein in sustaining nitric oxide (NO) production within endothelial cells, yet it undergoes degradation under oxidative stress, contributing to endothelial cell dysfunction. Citronellal (CT), a monoterpenoid, has been shown to ameliorate endothelial dysfunction induced by in atherosclerosis rats. However, whether CT can inhibit the degradation of GCH1 protein is not clear. It has been reported that ubiquitination may play a crucial role in regulating GCH1 protein levels and activities. However, the specific E3 ligase for GCH1 and the molecular mechanism of GCH1 ubiquitination remain unclear. Using data-base exploration analysis, we find that the levels of the E3 ligase Smad-ubiquitination regulatory factor 2 (Smurf2) negatively correlate with those of GCH1 in vascular tissues and HUVECs. We observe that Smurf2 interacts with GCH1 and promotes its degradation via the proteasome pathway. Interestingly, ectopic Smurf2 expression not only decreases GCH1 levels but also reduces cell proliferation and reactive oxygen species (ROS) levels, mostly because of increased GCH1 accumulation. Furthermore, we identify BH4/eNOS as downstream of GCH1. Taken together, our results indicate that CT can obviously improve vascular endothelial injury in Type 1 diabetes mellitus (T1DM) rats and reverse the expressions of GCH1 and Smurf2 proteins in aorta of T1DM rats. Smurf2 promotes ubiquitination and degradation of GCH1 through proteasome pathway in HUVECs. We conclude that the Smurf2-GCH1 interaction might represent a potential target for improving endothelial injury.
Acta Biochimica et Biophysica Sinica•2024•DOI: 10.3724/abbs.2023269
Previous studies have shown that puerarin plays a key role in protecting humans and animals from cardiovascular diseases. The exact mechanism of the therapeutic effect of puerarin on various cardiovascular diseases (protective effect on cardiomyocytes) is still unclear. In the present study, we identify the role of puerarin in an animal model of experimental heart failure (HF) and explore its underlying mechanisms. The HF rat model is induced by intraperitoneal injection of adriamycin (ADR), and puerarin is administered intragastrically at low, medium, and high concentrations. We demonstrate that puerarin significantly improves myocardial fibrosis and inflammatory infiltration and, as a result, improves cardiac function in ADR-induced HF rats. Mechanistically, we find for the first time that puerarin inhibits overactivated Na+/H+ exchange isoform 1 (NHE1) in HF, which may improve HF by decreasing Na+ and Ca2+ ion concentrations and attenuating mitochondrial damage caused by calcium overload; on the other hand, puerarin inhibits the activation of the p38 pathway in HF, reduces the expressions of TGF-β and proinflammatory cytokines, and suppresses myocardial fibrosis. In conclusion, our results suggest that Puerarin is an effective drug against HF and may play a protective role in the myocardium by inhibiting the activation of p38 and its downstream NHE1.
Acta Biochimica et Biophysica Sinica•2025•DOI: 10.3724/abbs.2025070
Diabetes mellitus (DM) is a metabolic and endocrine disorder with a projected global prevalence of 783 million by 2045. Individuals with type 2 diabetes face a 20–60% elevated risk of cognitive dysfunction, yet therapeutic options remain limited. This study investigates the efficacy of Schisandrin A (SchA), a bioactive lignan from Schisandra chinensis, in a streptozotocin-induced diabetic rat model. Rats were randomized into control, DM, DM+SchA, and Con+SchA groups. SchA treatment improved insulin sensitivity, reduced blood glucose, and significantly attenuated fear memory impairment. Histological analysis revealed decreased prefrontal cortex damage, enhanced synaptic protein expression, and reduced Aβ42 formation. Mechanistically, SchA suppressed microglial activation and inflammatory markers while increasing phosphorylation of insulin resistance pathway proteins. Furthermore, SchA mitigated ferroptosis by upregulating GPX4, SLC7A11, Nrf2, HO-1, and SIRT1 in the diabetic prefrontal cortex. These findings suggest that SchA alleviates diabetes-associated memory impairment by concurrently reducing neuroinflammation and ferroptosis, positioning SchA as a potential therapeutic agent for diabetes-related cognitive decline.