CONCLUSION

The NFS-based culture system provides a 3D space for cell attachment and migration. In the 3D NFS, cell-derived products can diffuse easily and tight cell-to-cell contact can be avoided. Whereas hydrogels can mimic the native 3D microenvironment, limited diffusion of chemokines and migration of cells hampers their use in 3D coculture of bacteria and phagocytes. Technically, the NFS can be easily assembled into the layer-by-layer system, which mimics multilayers of cells in tissue. Moreover, PCL nanofibers are inert and biocompatible in immune cell culture because the adhesion of BM-DCs to PCL nanofibers does not affect their activation status (8, 9). Finally, 3D migration to surrounding bacteria and phagocytosis processes in the NFS can be visualized though a live cell-imaging setup.

Thus, our NFS-based 3D culture system is widely applicable to the biomimetic study of various microbe infections.

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국문요약

호중구, 대식세포, 수지상 세포와 같은 전문적인 포식 세포들은 미생물을

활발히 에워싼다. 본 연구에서는, 염증 상태일 때 포식세포와 미생물간에

연관을 조사하기 위하여 생체 외 조건에서 3 차원적인 감염 모델을 개발하였다.

황색포도상구균과 포식세포들을 같이 배양하기 위해서 3 차원적 구조 내에서

다층 구조인 나노 섬유를 이용한 배양 시스템을 사용하였다. 표면에 부착된

황색포도상구균과 포식 세포들은 나노 섬유 안으로 이동이 가능하며,

포식세포들은 3 차원적 조건에서 포도상구균으로 이동하고 에워싼다. 또한 포밀

펩타이드 수용체 억제제를 처리하면 식균 작용의 비율이 3 차원적 조건에서는

감소를 하지만 2 차원적 조건에서는 감소를 하지 않았다. 황색포도상구균으로의

포식 세포의 이동은 나노 섬유 기반 다층 구조 배양 시스템을 이용하여

측정하였다. 상위의 나노 섬유 지지체 내 포식 세포들은 아래 층의 지지체로

이동을 하였다. 또한 황색포도상구균과 같이 배양한 포식 세포들에 의한

사이토카인과 케모카인은 분비 양상을 2 차원적과 3 차원적 조건일 때 비교를

하였다. 그리고 3 차원적인 3 차원 조건일 때 수지상 세포는 박테리아를

잡아먹은 호중구로 이동을 한 후, 호중구를 에워쌋다. 게다가 상위의 지지체에

있는 호중구와 대식 세포들은 다층 구조 지지체 배양 시스템에서 아래쪽의

지지체 내의 박테리아에 감염된 폐 상피세포로 이동을 확인했다. 그리고

박테리아에 감염된 폐의 상피세포에 박테리아를 감염시키면 3 차원적

조건에서만 종양괴사인자-알파와 인터류킨-1α 가 분비가 되는 것을 확인했다.

이것을 통해 나노 섬유를 이용한 3 차원적 배양 시스템은 생체 내 미생물에

대한 반응처럼 염증 반응을 흉내 낼 수 있다는 것을 증명하였다.