Microglial SIX2 suppresses lipopolysaccharide (LPS)-induced neuroinflammation by up-regulating FXYD2 expression.

Parkinson's disease (PD) is a severe neurodegenerative disease associated with the loss of dopaminergic (DA) neurons in the substantia nigra (SN). Although its pathogenesis remains unclear, microglia-mediated neuroinflammation significantly contributes to the development of PD. Here we showed that the sine oculis homeobox (SIX) homologue family transcription factors SIX2 exerted significant effects on neuroinflammation. The SIX2 protein, which is silenced during development, was reactivated in lipopolysaccharide (LPS)-treated microglia. The reactivated SIX2 in microglia mitigated the LPS induced inflammatory effects, and then reduced the toxic effect of conditioned media (CM) of microglia on co-cultured MES23.5 DA cells. Using the LPS-stimulated Cx3cr1-CreERT2 mouse model, we also demonstrated that the highly-expressed SIX2 in microglia obviously attenuated neuroinflammation and protected the DA neurons in SN. Further RNA-Seq analysis on the inflammatory activated microglia revealed that the SIX2 exerted these effects via up-regulating the FXYD domain containing ion transport regulator 2 (FXYD2). Taken together, our study demonstrated that SIX2 was an endogenous anti-inflammatory factor in microglia, and it exerted anti-neuroinflammatory effects by regulating the expression of FXYD2, which provides new ideas for anti-neuroinflammation in PD.

Dephosphorylation of Six2Y129 protects tyrosine hydroxylase-positive cells in SNpc by regulating TEA domain 1 expression.

Parkinson's disease (PD) is a neurodegenerative disease characterized by selective loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). We recently reported that Six2 could reverse the degeneration of DA neurons in a dephosphorylation state. Here we further identified that Eya1 was the phosphatase of Six2 that could dephosphorylate the tyrosine 129 (Y129) site by forming a complex with Six2 in damaged DA cells. Dephosphorylated Six2 then translocates from the cytoplasm to the nucleus. Using ChIP-qPCR and dual luciferase assay, we found that dephosphorylated Six2 down-regulates TEA domain1 (Tead1) expression, thus inhibiting 6-hydroxydopamine (6-OHDA)-induced apoptosis in DA cells. Furthermore, we showed Six2Y129F/Tead1 signaling could protect against the loss of SNpc tyrosine hydroxylase-positive (TH+) cells and improve motor function in PD model rats. Our results demonstrate a dephosphorylation-dependent mechanism of Six2 that restores the degeneration of DA neurons, which could represent a potential therapeutic target for PD.

[Effects of Drynaria total flavonoids on apoptosis of osteoblasts mediated by tumor necrosis factor-α].

OBJECTIVE: To investigate the influence of Drynaria total flavonoids on proliferation and apoptosis of osteoblasts in tumor necrosis factor-α (TNF-α)- mediated medium, so as to explore the mechanism of Drynaria total flavonoids in preventing and treating osteoporosis of rheumatoid arthritis. METHODS: Twenty Wistar rats with average weight of (200±20) g were randomly divided into two groups: blank control group and Qianggu capsule (Drynaria total flavonoids) group. Rats in Qianggu capsule group were fed with 75 mg Qianggu capsule daily for continuous 3 d. One hour after the last feed, blood samples were collected. The in vitro experiment of four groups was designed: blank control serum group, Drynaria total flavonoids-containing serum group, blank control serum plus TNF-α group and Drynaria total flavonoids-containing serum plus TNF-α group. Methyl thiazolyl tetrazolium method was used to detect the proliferation of osteoblasts. Flow cytometry was used to detect the apoptosis of osteoblasts and real-time fluorescent quantitative polymerase chain reaction to detect the expressions of Bcl-2 and Bax mRNAs in osteoblasts. RESULTS: Compared with the control serum, Drynaria total flavonoids-containing serum promoted the proliferation and decreased the apoptosis of osteoblasts in TNF-α-mediated inflammatory environment (P<0.05), and increased the ratio of Bcl-2 mRNA to Bax mRNA. CONCLUSION: In TNF-α-mediated inflammatory environment, Drynaria total flavonoids can promote the proliferation and decrease the apoptosis of osteoblasts by improving the ratio of Bcl-2 mRNA to Bax mRNA, which may be one of the mechanisms of Drynaria total flavonoids in preventing and treating osteoporosis of rheumatoid arthritis.

[Experimental study on effect of rhizoma drynariae flavone on bone destruction of collagen inducted arthritis rat].

OBJECTIVE: Through establishing the rat model of CIA to evaluate the effect and mechanism of Rhizoma Drynariae Flavone on bone destruction of CIA rat. METHODS: Subcutaneous injection of bovine type II collagen was used to induce Wistar rats to fall ill, and then established the rat model of CIA. The rats whose inflammation scores reached to two points or above were randomly divided into four groups, and were treated accordingly. The effect of Rhizoma Drynariae Flavone on bone destruction was evaluated. RESULTS: At 12 weeks after treatment, bone trabecular area percentage and bone trabecular number in Rhizoma Drynariae Flavone group, Rhizoma Drynariae Flavone-1/2 Etanercept group, Etanercept group was obviously higher than that of sterilization water group (P < 0.05); and the trabecular resolving power of these groups was obviously less than that of sterilization water group (P < 0.05). CONCLUSION: Rhizoma Drynariae Flavone can obviously inhibit inflammation of joint bone destruction of CIA rats,the effect may be related with bone trabecular number reduction and trabecular resolving power increasing.

[Effect of Bushen Qianggu decoction on the proliferation of synovial fibroblasts and expression of PCNA and Bcl-2].

OBJECTIVE: To observe the effects of Bushen Qianggu decoction proliferation and PCNA and Bcl-2 expression. METHODS: Serum containing BQD was made and synovial fibroblasts were separated and cultured and passaged in vitro. Four groups were divided as 20% blank control group, serum containing 20% Tripterygium wilfordii multi-glycosides drug (TWMD), 20% of serum containing high and low of BQD, respectively. Serum containing drugs of different concentration were added into the synovial fibroblasts of the third generation, and then the synovial fibroblasts were cultured continued. The effects of different drugs on synovial fibroblasts and PCNA and Bcl-2 expression were observed. RESULTS: Compared with the control serum, BQD-containing serum promoted the apoptosis of synovial fibroblasts (P < 0.000 1); especially, high dose could inhibit proliferation. The expression of PCNA and Bcl-2 was significantly lower in BQD-containing serum (P < 0.000 1 vs control group). CONCLUSION: BQD can promote the apoptosis of synovial fibroblasts by improving of expression of PCNA and Bcl-2, which may be one of the mechanisms of BQD in preventing and treating osteoporosis of rheumatoid arthritis.