Research Of The Nerve Protective Effect Of Hsp22 To PINK1 Mutations PD Transgenic Flies

Objective: Parkinson’s disease(PD), also known as paralysis agitans,is the second common neurodegenerative diseases. Clinical manifestations include static tremor, muscle rigidity, bradykinesia and abnormal gait posture, etc. [1]. Features of PD neuropathology include degeneration and progressive depigmentation of the substantia nigra dopaminergic cells density area, part of the surviving neurons have proteins’ inclusions(Lewy body). People with the age of over 60 are vulunerable to develop PD, however, in recent years, there is a trend that people younger than 60 develop PD. PD’s biggest hazard lies in the quality of life in patients are serious decline, the life cannot provide by themselves, and often appear a variety of complications. But the exact pathogenesis of PD is not yet clear. Studies have shown that mitochondrial dysfunction, oxidative stress and abnormal protein modification and misfolding cause dopaminergic neuron dysfunction arethe most important pathogenesis of PD. Earlier studies have found that mitochondria of platelet of PD patients was hypofunction. Hypofunction of mitochondrial complex in different tissues of human body is associated with PD, this correlation has been further confirmed in multiple molecular biological researches. Since found nigra toxin MPP + can restrain the activity of the complex I(C1), mitochondria became a hot spot in the study of the pathogenesis of PD. Mutations of PINK1(PTEN-induced kinase 1) and Parkin have been found in autosomal recessive PD, these two proteins encoded by PINK1 and Parkin play an important role in improving the mitochondrial functions[2].In the known pathogenic genes of familial and sporadic PD, PINK1 is the only one located in mitochondria[3]. Pink1B9 is a mutant gene of truncated PINK1 gene. Drosophila model of Pink1B9 mutations reappear the several important characteristics of PD. In particular, Pink1B9 provide the important information of mitochondrial dysfunction and molecular basis about early-onset Parkinson’s disease [4], it has been used to study the neural degeneration and molecular mechanisms of neural degeneration [5].Heat shock protein 22(Hsp22 / HspB8) is one of the most important members of the small heat shock proteins(HSPB) family.Hsp22 located in mitochondria, with a wide range of biological effects including molecular chaperone, antioxidation, apoptosis, apoptosis resistance, prolong life[6]. In recent years, in the study, we found thatHsp22 plays the neural protection role in neurodegenerative diseases such as Alzheimer disease, Huntington disease,distal spinal muscular atrophy and so on [7、8].Therefore, this experiment chooses PD transgenic flies model of Pink1B9 mutation to explore whether up-regulated Hsp22 has the neural protection to PD, and study the neural protection mechanism.Methods: MHC-GAL4 was selected as promoter, using the classical GAL4-UAS system, hybridizes with W1118. The hybrid, as a normal control, is expressed MHC-GAL4. Then MHC-GAL4 hybridizes with Pink1B9, selective expressing gene that missing genes Pink1 functions(Pink1B9) in flies’ muscle, constructing MHC- PD transgenic flies GAL4/ UAS system model, and then through the construction of hybrid Hsp22 and Hsp22RNAi gene intervention MHC-GAL4/UAS system PD transgenic flies model of Pink1B9 mutation. The four groups of flies’ models, respectively selected 100 male fruit flies. At the fifth day and fifteenth day, respectively test the rate of abnormal wings posture and the rate of flight/jump ability. Through the electron microscope, observe mitochondrial morphology of indirect flight muscles with four groups of males at the fifth day. Results: We successfully build four transgenic flies.Compared with normal flies model, we find the abnormal wing posture rate of PD transgenic flies of the MHC–GAL4 system PINK1 mutations significantly increased, and the flight/jump ability significantly reduced.At the same time, after Hsp22 gene intervention, the drosophila modelcan obvious improve the abnormal wing posture rate and the flight/jump ability of the drosophila disease model, and greatly improving the integrity of the mitochondrial morphology in the flight muscles, etc. On the contrary, Hsp22 RNAi genes intervent drosophila disease model has no obvious improvement. Conclusions:(1) Hsp22 up-regulated expression of PINK1 mutations PD transgenic flies model with nerve protective effect.(2) Hsp22 up-regulated expression plays a neural protective role in PD transgenic flies model.