Hydrogen Sulfide Inhibits Homocysteine-induced Autophagy In HT22 Cells Via Upregulation Of The BDNG-TrkB Pathway

Objective: in this work, we study whether H2 S inhibits homocysteine-induced cell autophagy in HT22 cells via upregulation of the BDNF-TrkB pathway.Method: The autophagy of HT22 cellular was tested by the expression of detected cell autopgagy-associated proteins LC3II/I, P62 and Bcelin-1 determined by western blotting, the autopagy determined by electron microscopy. BDNF protein and p-TrkB/TrkB protein levels were assessed by western blotting. The BDNF-TrkB pathway were blocked by k252 a.RESULT: 1. Hcy(2.5, 5,10 mmol/L, for 24h) dose-dependently increased expressions of autophagy related protein LC3, Beclin-1, and number of autophagic vacuoles, whereas downregulated p62 protein, indicating that Hcy induces the autophagy of HT22 cells. 2. NaHS(the donor of H2 S, 100, 200, 400 μmol/L, for 24h) dose-dependently inhibited the increases the expressions of autophagy related protein LC3, Beclin-1, and number of autophagic vacuoles, whereas downregulated p62 protein, indicating that H2 S prevents Hcy-induced autophagy in HT22 cells. 3. The expression of BDNF and p-TrkB/TrkB in HT22 cells was dose-dependently reduced by treatment of Hcy(2.5, 5, 10 mmol/L, 24h), suggesting that Hcy suppress the expression of BDNF and p-TrkB/Trk B in HT22 cells. 4.Treatment with NaHS(100, 200, 400 μmol/L, for 24h) not only dose-dependently increased the levels of BDNF protein and p-TrkB/TrkB protein expression in HT22 cells but also reversed the derease the levels of BNDF protein and p-TrkB/TrkB protein expression induced by exposed to 5 mmol/L of Hcy for 24 h, indicating that H2 S up-regulates the expression of BDNF protein and p-TrkB/TrkB protein in HT22 cells. K252a(a inhibitor of BDNF-TrkB, 10 nmol/L) blocked the inhibitory actions of NaHS(400 μmol/L) in Hcy(5 mmol/L, for 24h)-induced increases in the expressions of autophagy related key protein LC3, Beclin-1, and number of autophagic vacuoles, whereas downregulated p62 protein, indicating that BDNF-TrkB pathway mediates the inhibitory role of H2 S in Hcy-induced autophagy of HT22 cells.Conclusion: Hydrogen Sulfide inhibits homocysteine-induced autophagy in HT22 cells via upregulation of the BDNF-TrkB pathway.