C. difficile 톡신이 야기하는 대장상피세포 미세소관 변형에 대한 초산의 억제 효능

국문 초록 (Abstract)

급성위막성대장염(Pseudomembranous colitis)은 C. difficile 세균이 분비하는 톡신A에 의해 유발되는 것으로 알려져 있다. 톡신A에 의한 점막 상피세포의 장벽기능 감소가 발병 원인으로 알려져 있다. 최근 연구에 의하면 톡신 A는 대장상피세포 속 HDAC-6의 활성을 높여 튜블린의 탈아세틸화를 증가시키는 것으로 알려져 있다. 튜블린 단백질의 탈아세틸화는 미세소관 불 형성을 초래하여 점막 상피세포의 극단적인 세포 형태 변형을 야기하게 되며 결국 상피세포의 고유기능인 장벽 기능이 파괴된다고 알려져 있다. 최근 연구자 등은 potassium acetate가 톡신A에 의한 튜블린 탈아세틸화와 미세소관 불 형성을 회복시켜 장염을 유의하게 억제함을 보고하였다. 따라서 본 연구에서는 아세틸기를 포함하는 또 다른 간단한 화학구조의 초산을 적용하여 톡신A의 세포독성을 억제하는지 확인해보고자 하였다. 인간 대장상피세포에서 초산 자극은 튜블린 단백질의 아세틸화를 유의하게 증가시켰다. 또한 초산은 대장상피세포 속 미세소관 형성과정도 강하게 촉진시킴을 확인하였다. 초산은 톡신A에 의한 튜블린 탈아세틸화와 미세소관 불 형성 그리고 세포독성 모두를 유의하게 회복시켰다. 이상의 결과는 초산에 의한 미세소관 형성 촉진이 톡신A에 의해 초래되는 세포골격계 파괴와 그로 인한 세포독성을 억제할 수 있음을 보여준다. 따라서 초산이 톡신A의 작용을 차단하여 위막성대장염 증상을 완화시킬 수 있는 치료제로서 개발 가치가 있음을 보여준다.

다국어 초록 (Multilingual Abstract)

Clostridium difficile (C. difficile) toxin A is known to cause acute gut inflammation in humans and animals by triggering cytoskeletal disorganization in gut epithelial cells. In human colonocytes, toxin A blocks microtubule assembly by directly increasing the enzymatic activity of histone deacetylase-6 (HDAC-6), a tubulin-specific deacetylase, thereby markedly decreasing tubulin acetylation, which is essential for microtubule assembly. Microtubule assembly dysfunction-associated alterations (i.e., toxin A-exposed gut epithelial cells) are believed to trigger barrier dysfunction and gut inflammation downstream. We recently showed that potassium acetate blocked toxin A-induced microtubule disassembly by inhibiting HDAC-6. Herein, we tested whether acetic acid (AA), another small acetyl residue-containing agent, could block toxin A-induced tubulin deacetylation and subsequent microtubule assembly. Our results revealed that AA treatment increased tubulin acetylation and enhanced microtubule assembly in an HT29 human colonocyte cell line. AA also clearly increased tubulin acetylation in murine colonic explants. Interestingly, the AA treatment also alleviated toxin A-induced tubulin deacetylation and microtubule disassembly, and MTT assays revealed that AA reduced toxin A-induced cell toxicity. Collectively, these results suggest that AA can block the ability of toxin A to cause microtubule disassembly-triggered cytoskeletal disorganization by blocking toxin A-mediated deacetylation of tubulin.

목차 (Table of Contents)

• 서론
• 재료 및 방법
• 결과 및 고찰
• References
• 초록

참고문헌 (Reference)

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