• 생명과학회지
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• 제28권12호
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• pp.1397-1405
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• 2018

미토콘드리아는 세포안에서 에너지 공급, 칼슘 이온 저장, 활성산소 생성, 세포 자살과 같은 다양한 기능을 수행한다. 이러한 기능을 통해, 미토콘드리아는 줄기세포의 유지, 증식, 그리고 분화에 관여한다. 뇌에서 뇌실 하 영역(subventricular zone, SVZ)에는 일평생 새로운 신경세포를 생성하는 신경줄기세포(neural stem cell, NSC)가 존재한다. 하지만, SVZ NSCs에서 미토콘드리아의 역할에 대한 연구는 많이 알려져 있지 않다. 이번 연구에서 우리는 미토콘드리아의 complex I 저해제인 rotenone이 SVZ NSCs의 증식과 분화를 다른 방식으로 방해한다는 것을 보여주었다. 증식 중인 신경줄기세포에서, rotenone은 세포분열을 감소시켰는데, 이때 세포분열은 히스톤 H3에 인산기가 붙어있는 지를 측정하여 확인하였다. Rotenone을 50 nM 농도로 증식 중인 신경줄기세포에 처리했을 때, 세포사멸은 발생하지 않았다. 한편, 분화 중인 신경줄기세포에 rotenone을 처리한 경우, 신경세포와 희소 돌기아교 세포(oligodendrocyte)으로의 분화가 억제되었고, glial fibrillary acidic protein (GFAP)를 발현하는 성상세포(astrocyte)에는 영향이 없었다. 흥미롭게도, 4-6일 동안의 분화 과정 동안 rotenone이 처리된 신경줄기세포에서 대조군 보다 더 많은 세포 수가 관찰 되었는데, 이는 증식 과정 중의 rotenone의 효과와 다른 것이다. 이에, 우리는 rotenone이 세포 자살은 감소시켰으나, 세포 분열에는 영향을 끼치지 않았음을 관찰하였다. 세포 자살의 경우는 cleaved caspase-3를 측정함으로써 확인하였다. 이러한 결과들은 SVZ 신경줄기세포의 증식과 분화 모두에 제대로 작동하는 미토콘드리아가 있어야 함을 제안하고 있다. 게다가, 이러한 과정에서 미토콘드리아는 세포 분열과 세포자살에 관여할 수도 있을 것이다.

• Journal of Korean Neurosurgical Society
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• 제30권6호
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• pp.688-698
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• 2001

Objectives : Parkinson's disease is a well-known neurodegenerative disease characterized by dopaminergic cell death in the substantia nigra. The reactive gliosis by activated astrocytes and microglias is no more regarded as a simple sequel of neuronal cell death. Microglial activation takes place in a stereotypic pattern with graded morphologic and functional(resting, activated and phagocytic) changes. In Parkinson's disease animal model, the degree of microglial activation along the nigro-striatal dopaminergic tract has not been studied intensively. The purpose of this study was to elucidate the characteristics of microglial reaction and to grade its degree of activation at substantia nigra and corpus striatum using 6-hydroxydopamine induced rat model of Parkinson's disease. Methods : Using Sprague-Dawley rat, parkinsonian model was made by 6-hydroxydopamine(OHDA) induced destruction of medial and lateral substantia nigra(SN). The rat was sacrificed 3-, 5-, 7-, 14- and 21-day-after operation. For control group, we injected saline with same manner and sacrificed 3-day after operation. With immunohistochemistry, we examined dopaminergic neuronal cells and microglial expression using tyrosine hydroxylase (TH) and OX-42 antibodies, respectively. Also we performed in situ hybridization for osteopontin, a possible marker of subset in activated microglia. Results : 1) In lesioned side of substantia nigra and corpus striatum, the TH immunoreactivity was markedly decreased in whole experimental groups. 2) Using optical densitometry, microglia induced immunoreactivity of OX-42 was counted at SN and corpus striatum. At SN, it was increased significantly on the lesioned side in control and all time-dependent experimental groups. At striatum, it was increased significantly in post lesion 3-day group only(p <0.05). Compared to control group, immunoreactivity of OX-42 on lesioned side was increased in groups, except post lesion 21-day group, at SN. Only post lesion 3-day group showed significance at striatum(p <0.05). Compared to SN region, immunoreactivity of OX-42 was much weaker in striatum. 3) Microscopically, the microglias showed typically different activation pattern. At SN, numerous phagocytic microglias were found at pars compacta and reticularis of lesion side. At striatum, no phagocytic form was found and the intensity of staining was much weaker. 4) At SN, the immunoreactivity of osteopontin showed definite laterality and it was markedly increased at pars compacta of lesion side with relatively short duration time. At striatum, however, it was not detected by in situ hybridization technique. Conclusion : The nigral 6-OHDA induced rat model of Parkinson's disease revealed several characteristic patterns of microglial reaction. At SN, microglias was activated shortly after direct neuronal damage and maintained for about three weeks. In contrast, despite of sufficient dopaminergic insufficiency at striatum, activation of microglias was trivial, and distinguished 3 day later. Antegrade slow neuronal degeneration is major pathophysiology in striatal dopaminergic deficiency. So, the acuteness of neuronal damage and consequential degree of neuronal degeneration may be important factor for microglial activation in neurodegenerative diseases such as Parkinson's disease. Additionally, osteopontin may be a possible marker for several subsets of activated microglia, possibly the phagocytic form.