1,25-dihydroxycholecalciferol 이 Sol 8 세포내 calpain계 mRNA 및 단백질 발현에 미치는 영향

본 연구는 근육내 1,25-(OH)₂ D₃가 calpain계 효소의 작용기전에 미치는 영향을 구명코자 골격근 세포의 일종인 Sol 8 세포주를 이용하여 실험을 실시하였다. 실험 결과 1,25-(OH)₂ D₃ 100 nM 처리 시 세포수와 활성도를 가장 낮았으며, 1,25-(OH)₂ D₃ 처리는 u, m-calpain의 mRNA와 단백질 발현을 증가 시키는 반면 calpastatin의 mRNA 및 단백질 발현은 감소시켰다. 이러한 결과는 세포내 vitamin D receptor의 발현 증가에 의한 것으로 사료되며, 이를 통한 세포내 칼슘 증가에 기인하였을 것으로 사료된다. 하지만 1,25-(OH)₂ D₃ 처리 시 Sol 8 세포내 칼슘 농도의 변화는 없었다. 따라서 위의 결과를 종합해 보면, Sol 8 세포내 1,25-(OH)₂ D₃에 의한 calpain계 효소의 변화는 기존의 보고 의외에 또 다른 작용 기작이 존재할 가능성이 있으며, 이를 확인하기 위한 보완 실험이 추후 더 진행 되어야 한다고 생각된다.

Tenderness has been identified as the single most important palatability factor affecting consumer satisfaction of beef meat. A couple of recent methods to activate calpain-induced tenderization has been the oral supplementation of vitamin D₃ or its metabolites. To improve understanding of the regulation of calpain protease system in muscle, the effects of 1,25-Dihydroxy colecalciferol (1,25-(OH)₂ D₃) on calpain protease enzymes were studied using Sol 8 cell line. In criteria of cell number and proliferation, a concentration of 100 nM 1,25-(OH)₂ D₃ most inhibited the myogenic differentiation of Sol 8 cells. 1,25-(OH)₂ D₃ increased mRNA gene expressions of u-calpain while that of m-calpain and calpastatin showed (p < 0.05) the opposite expression pattern. The amount of u-calapin and m-calpain protein were the highest (p < 0.01) at 4h and 2h incubation with 1,25-(OH)₂ D₃, respectively, whereas calapstatin level was significantly decreased. There was no changes in calcium uptake into inner cells by 100 nM 1,25-(OH)₂ D₃ in spite of significant (p < 0.05) up-regulation in vitamin D receptor gene expression. The results indicated that the calpain protease system of Sol 8 cell was greatly influenced by 1,25-(OH)₂ D₃ without alteration of calcium concentration of inner cell. Therefore, the role of vitamin D receptor remains to be further elucidated later.