As a potential therapeutic agent, Akt1as well as its downstream substrates, offer great promise for the development of therapeutics against a number of neurodegenerative disorders that may be acute in nature, such as stroke, or more sub-acute in duration, such as Alzheimer's disease. Initially believed to have cellular functions directed primarily toward cell survival and growth, Akt1 is now seen as a potential broad cytoprotective agent. Akt1 can offer cellular protection not only through the modulation of intrinsic apoptotic machinery, but also through the activation of survival signal pathways in the cells. Akt1 drives cellular survival through a series of distinct pathways that involve the Forkhead family of transcription factors, GSK-3ß, ß-catenin, eIF2B, c-Jun, CREB, Bad, IKK, p53, and JIPs. Yet, it is evident that further work that clarifies the cellular environment controlled by Akt1 will be of exceptional value to refine our knowledge of Akt1 and to maximize the potential of this protein as a therapeutic agent.
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- 국문 요약 -
Akt1 과발현을 유도한 인간 신경줄기 세포주의 마우스 뇌출혈 뇌졸중 모델에서의 치료 효과
아주대학교 대학원 의학과
김 미 경
(지도교수 : 김 병 곤)
Akt1 분자는 serine/threonine 키나아제의 하나로, 세포의 성장과 증식, 생존 그리고 에너지 대사와 관련된 신호전달체계에서 중요한 역할을 하는 효소 중의 하나이다. 선행된 연구를 통해 래트 뇌출혈 뇌졸중 모델에 인간유래 신경세포줄기를 이식하여, 이식한 줄기세포들의 뇌 손상 조직으로의 선택적인 이동 능력과 모델 동물의 행동적 기능상의 회복을 확인 할 수 있었다. 하지만 이식 된 줄기세포의 낮은 생존율로 인해, 세포 이식 이후의 살아있는 세포에 의한 지속적인 효과에 관한 우려를 낳았다. 이에 본 연구에서는 대표적인 survival molecule 로 알려진 Akt1 유전자를 인간 신경줄기세포 내로 도입,
과발현을 유도하여 이러한 세포를 이용한 질병 치료책에 있어서 이식된 세포의 장기간의 생존 효과를 보고자 하였다.
본 실험은 먼저 Akt1 과발현 신경줄기 세포주를 만들어 in vitro 상에서 과산화수소에 의한 세포사에 대한 저항성을 확인하고, 또한 뇌졸중 상태와 유사한 환경을 가지는 산소 및 글루코스 고갈 실험에서의 세포의 생존력을 비교해 보았다. 그 결과 Akt1 이 과발현 되는 세포주가 그렇지 않은 모세포주보다 강한 생존력을 가지고 있음을 알 수 있었다. 또한 마우스를 이용한 in vivo 동물 실험을 통해 확인을 해 본 결과, Akt1 이 과발현 되는 세포주가 그렇지 않은 대조군의 세포주에 비해 이식 후 일정 시간 후에 보다 더 오래 생존하고, 유지 되고 있음을 확인 할 수 있었다.
이렇듯 본 연구에서는 과발현 되는 Akt1 에 의해 이식하는 신경 줄기 세포의 생존율을 향상시키고, 이식한 세포의 장기간의 생존으로 인해 신경 줄기세포의 지속적인 neuroprotection 효과를 확인할 수 있었다.
핵심어 : 신경 줄기 세포, Akt1/단백질 키나아제 B, 산소-포도당 박탈, 뇌출혈,
세포 이식