RESUMEN
Parkinson's disease (PD) is the second major neurodegenerative disease.The pathogenesis of PI) is still unclear.It is generally believed that neural damage, mitochondrial dysfunction, inflammation, oxidative stress and autophagy dysfunction caused by the transmission and aggregation of a- synuclein play an important role in the occurrence and development of PD.More and more research show- that metabolic disorder is one of the pathogenesis of PD.We examined whether overexpression of a- synuclein could induce metabolic disorder in mice and the possible mechanisms.Mice were divided into two groups: Thyl-aSYN transgenic mice (TG) and the control wild-type (WT) group.The rotarod test was used to analyze motor function in mice.We detected the body weight, plasma insulin content, glucose tolerance and insulin tolerance in the two group mice.The morphology of islets in the two groups were observed by hematoxylin eosin (HE) staining, and the islets were isolated to detect the glucose- stimulated insulin secretion (GSIS).The results showed that compared with the WT group, exercise tolerance of 12-month-old TG group decreased by 23.1% (P < 0.05) , body weight increased by 7% (P < 0.01), glucose tolerance decreased (P < 0.05), insulin tolerance decreased (P < 0.05), and insulin contents in the peripheral blood decreased by 20% (P < 0.05).Compared with the WT group, the levels of ce -syn proteins in the pancreas of the TG group increased by 1.32 times (P < 0.05) , the area of islets in the TG group decreased (P < 0.05 ) , the number of islets decreased (P < 0.01) , and the insulin secretion function decreased (P< 0.01).This study showed that the role of a-synuclein in PD is not limited to the damage of dopaminergic neurons, it also can affect metabolism and the morphology and function of peripheral organs, which provides a new theoretical basis for the pathogenesis of PD.
RESUMEN
Objective To study whether and how rotenone reduces the activity of protein phophatase 2A (PP2A). Methods MN9D cells (mouse midbrain dopaminergic cell line) were divided into normal group (normal cultured), con-trol group (dimethyl sulfoxide of same volume with rotenone group was added in medium), rotenone group (50 nmol/L rotenone was added to the culture medium for 24 hours) and rotenone+C2 group (pretreatment of 5 mol/L C2-ceramide for eight hours, and then exposed to 50 nmol/L rotenone for 24 hours). MTT was used to detect cell viability. Total PP2A levels and tyrosine phosphorylation levels were measured with Western blotting. PP2A activity was detected with colorimetric assay.Results Compared with the control group, the cell viability reduced (P<0.01), phosphorylation of tyrosine 307 of PP2A inceased (P<0.01), and activity of PP2A decreased in the rotenone group (P<0.05). And compared with the rote-none group, the cell viability improved (P<0.01), phosphorylation of tyrosine 307 of PP2A deceased (P<0.01), and activity of PP2A increased (P<0.05) in the rotenone+C2 group. Conclusion Rotenone can inhibit activity of PP2A through increasing phosphorylation of tyrosine 307 at the catalytic subunit of PP2A, which might be involved in reducing cell viability, and implicate a new treatment strategy for Parkinson's disease.