Genetic deletion of zinc transporter ZnT3 induces progressive cognitive deficits in mice by impairing dendritic spine plasticity and glucose metabolism.

Zinc transporter 3 (ZnT3) is abundantly expressed in the brain, residing in synaptic vesicles, where it plays important roles in controlling the luminal zinc levels. In this study, we found that ZnT3 knockout in mice decreased zinc levels in the hippocampus and cortex, and was associated with progressive cognitive impairments, assessed at 2, 6, and 9-month of age. The results of Golgi-Cox staining demonstrated that ZnT3 deficiency was associated with an increase in dendritic complexity and a decrease in the density of mature dendritic spines, indicating potential synaptic plasticity deficit. Since ZnT3 deficiency was previously linked to glucose metabolism abnormalities, we tested the expression levels of genes related to insulin signaling pathway in the hippocampus and cortex. We found that the Expression of glucose transporters, GLUT3, GLUT4, and the insulin receptor in the whole tissue and synaptosome fraction of the hippocampus of the ZnT3 knockout mice were significantly reduced, as compared to wild-type controls. Expression of AKT (A serine/threonine protein kinase) and insulin-induced AKT phosphorylation was also reduced in the hippocampus of ZnT3 knockout mice. We hypothesize that the ZnT3 deficiency and reduced brain zinc levels may cause cognitive impairment by negatively affecting glycose metabolism via decreased expression of key components of insulin signaling, as well as via changes in synaptic plasticity. These finding may provide new therapeutic target for treatments of neurodegenerative disorders.

Phytotoxic neo-clerodane diterpenoids from the aerial parts of Scutellaria barbata.

Bioactivity guided the isolation of extracts from the aerial parts Scutellaria barbata D. Don to discover neo-clerodane diterpenoids with potent phytotoxic activity. Of the 34 isolates, 13 neo-clerodane diterpenoids were described for the first time. The structures of these undescribed compounds were elucidated by extensive analysis of NMR spectroscopic data, and the absolute configurations of scutebarbolides A and L and scutebata W were determined by X-ray diffraction. The phytotoxic activity of all compounds against the growth of the roots and shoots of L. perenne and L. sativa seedlings were first reported, and some compounds showed considerable inhibitory effects, especially scutebarbolide K, whose inhibition rates were higher than those of the positive control at concentrations ranging from 25 to 200 µg/mL. When L. perenne and L. sativa seedlings were treated at a concentration of 200 µg/mL, scutebarbolide K caused wilting symptoms on and finally death of these two tested plant seedlings. In addition, the structure-activity relationships of these neo-clerodane diterpenoids were also discussed.

Oridonin suppresses autophagy and survival in rheumatoid arthritis fibroblast-like synoviocytes.

Context: Oridonin exhibits various pharmacological and physiological activities, including antioxidant, antibacterial, anti-inflammatory, pro-apoptotic, anticancer and neurological effects. However, its role in rheumatoid arthritis (RA) is yet to be revealed.Objective: We evaluated the effects of oridonin on the survival and autophagy of RA-fibroblast-like synoviocytes (FLSs).Materials and methods: RA-FLSs were treated with oridonin at serial concentrations of 0, 2, 4, 6, 8 and 10 µg/mL for 24, 48 and 72 h. Then, cell proliferation and apoptosis were measured. A GFP-LC3 plasmid was transfected into the cells to determine autophagy.Results: Oridonin suppressed RA-FLS proliferation in a dose-dependent manner. The half maximal inhibitory concentrations (IC50) of oridonin at 24, 48 and 72 h were 8.28, 7.88 and 8.35 µg/mL, respectively. Treatment with oridonin for 24 h increased apoptosis by 4.1%, and increased the protein levels of Bax and cleaved caspase-3 but significantly decreased the levels of IL-1ß in the culture supernatant (p < 0.05). In addition, 6 h of oridonin treatment significantly decreased the number of GFP-LC3 punctate dots and inhibited the protein levels of ATG5 and Beclin1 by 80.01% and 42.12%, respectively. Chloroquine (CQ) significantly reinforced the effects of oridonin on inhibition of autophagy, suppression of proliferation, and induction of apoptosis in RA-FLSs (p < 0.05).Conclusions: Our results indicate that treatment with oridonin in combination with CQ inhibits autophagy and cell proliferation and induces apoptosis in RA-FLSs more effectively than treatment oridonin alone. This finding indicates that oridonin is a potential therapeutic agent for RA.

Treatment with Melittin Induces Apoptosis and Autophagy of Fibroblastlike Synoviocytes in Patients with Rheumatoid Arthritis.

BACKGROUND: Melittin, the major medicinal component of honeybee venom, exerts antiinflammatory, analgesic, and anti-arthritic effects in patients with Rheumatoid Arthritis (RA). RA is an inflammatory autoimmune joint disease that leads to irreversible joint destruction and functional loss. Fibroblast-Like Synoviocytes (FLS) are dominant, special mesenchymal cells characterized by the structure of the synovial intima, playing a crucial role in both the initiation and progression of RA. OBJECTIVE: In this study, we evaluated the effects of melittin on the viability and apoptosis of FLS isolated from patients with RA. METHODS: Cell viability was determined using CCK-8 assays; apoptosis was evaluated by flow cytometry, and the expression levels of apoptosis-related proteins (caspase-3, caspase-9, BAX, and Bcl-2) were also determined. To explore whether melittin alters inflammatory processes in RA-FLS, IL-1ß levels were determined using an enzyme-linked immunosorbent assay (ELISA). Furthermore, we performed GFP-LC3 punctate fluorescence dot assays and western blotting (for LC3, ATG5, p62, and Beclin 1) to assess autophagy in RA-FLS. RESULTS: Our results show that melittin can significantly impair viability, promote apoptosis and autophagy, and inhibit IL-1ß secretion in RA-FLS. CONCLUSION: Melittin may be useful in preventing damage to the joints during accidental local stimulation.