调控内源性甲醛：硫化氢抗帕金森病的新机制

To further understand the pathogenesis mechanism of Parkinson's disease (PD) from a novel perspective is important for the prevention and treatment of PD. H2S is a new breakthrough for the prevention and treatment of PD, however, the mechanism needs to be further elucidated. Our previous work found that the accumulation of endougous formaldehyde in the brain is closely associated with PD and H2S can regulate the generation of endogenous formaldehyde. Therefore, we speculate that endogenous formaldehyde is a novel perspective for further elaborating the pathogenesis mechanism of PD and H2S prevents PD through regulating the level of endogenous formaldehyde in brain. Thus, in the animal models of PD, we will observe the changes of the contents of endogenous formaldehyde and the expression levels of its important metabolic enzyme (SSAO, ADH-3 and ALDH-2) in brain and explore the effects of the changes of endogenous formaldehyde levels on PD in order to clear that endogenous formaldehyde participates in the formation of PD, explore the protective effects of H2S on PD and the effect of H2S on the generation of endogenous formaldehyde in the brain of PD animal model in order to clarify that H2S antagonizes PD through regulating the generation of endogenous formaldehyde, and analyze the direct scavenging effect of H2S on formaldehyde and the role of H2S in the expression of SSAO, ADH-3 and ALDH-2 in brain in order to reveal the mechanism underlying the role of H2S in regulation of endogenous formaldehyde. This project will reveal the mechanisms of PD and the anti-PD role of H2S and provide new ideas and targets for the prevention and treatment of PD from the new perspective of endogenous formaldehyde.

从新的视角进一步认识帕金森病(PD)的发病机制，对防治PD具有重要意义。H2S是防治PD的新突破口，其机制有待深入阐明。我们前期工作发现脑内甲醛蓄积与PD密切相关，H2S可调控内源性甲醛的生成。本课题立足于内源性甲醛是进一步阐释PD机制的新视角，设想H2S可通过调控内源性甲醛抗PD。本项目将在PD动物模型上，观察脑内甲醛含量及其重要代谢酶(SSAO、ADH-3 和 ALDH-2)表达水平的变化、探讨改变脑内源性甲醛水平对PD的影响，以明确脑内源性甲醛的蓄积参与了PD形成；探讨H2S对PD的拮抗作用以及H2S对动物脑内源性甲醛生成的影响，以明确H2S可通过调控内源性甲醛而拮抗PD；分析H2S对甲醛的直接清除作用和对脑组织SSAO、ADH-3 和 ALDH-2表达的影响，以揭示H2S调控内源性甲醛的机制。从内源性甲醛这一新视角揭示PD机制和H2S抗PD机理，为PD的防治提供新思路和靶点。

本课题主要探讨硫化氢（H2S）是否通过抑制黑质内多巴胺能神经元丢失及凋亡和Warburg效应、增强黑质自噬水平和皮层内源性甲醛代谢拮抗6-OHDA大鼠的帕金森样病变（行为学和黑质病变），并进一步阐述上述现象是否由Leptin介导。本课题通过阿扑吗啡旋转实验、旷场实验、步态调整实验和圆筒实验检测到H2S(以NaHS为供体)能够逆转6-OHDA大鼠的帕金森样行为。同时发现NaHS可使6-OHDA大鼠黑质组织中神经元丢失减少、凋亡细胞数率减少、caspase-3和Bax表达降低、Bcl-2表达升高，表明H2S可拮抗6-OHDA诱导的黑质多巴胺能神经元丢失及凋亡。以上发现证实H2S对PD具有拮抗作用。.另外，我们发现NaHS处理6-OHDA大鼠后，(1)黑质组织中PKM2、HK2、PDK1和LDHA酶表达水平明显降低，PDH酶表达水平明显升高，表明H2S可拮抗6-OHDA对大鼠黑质组织中Warburg效应的抑制作用；(2)黑质组织细胞内的自噬小体明显减少，自噬溶酶体的数量显著增加，Beclin-1蛋白、LC3II明显减少和p62表达水平也显著减少，表明H2S可拮抗6-OHDA对大鼠黑质组织中的自噬的阻断作用；(3)皮层内源性甲醛代谢生成酶表达增加。以上结果表明H2S的抗PD作用可能与其增强黑质Warburg效应、改善黑质自噬、增强内源性甲醛代谢有关。. 我们进一步发现H2S明显增加6-OHDA大鼠黑质组织中leptin蛋白的表达，使用leptin拮抗剂后，可逆转H2S对6-OHDA大鼠行为学、黑质病变的改善作用，还可抑制H2S对6-OHDA大鼠黑质Warburg效应、自噬和内源性甲醛代谢的增强作用，表明H2S通过上调leptin增强黑质Warburg效应、自噬和内源性甲醛代谢而拮抗6-OHDA大鼠的帕金森样病变。. 本课题的研究明确了H2S对PD的干预作用，为PD的防治提供了新的突破口。同时也从调控leptin、Warburg效应、自噬和内源性甲醛代谢等方面明确了H2S抗PD的作用机制，为PD的防治提供了新颖的靶点。