Bioengineering Laboratory, Department of Chemical and Biological Engineering, University at Buffalo, the State University of New York, Amherst, NY 14260, USA.
J Cell Sci. 2013 Jun 15;126(Pt 12):2718-29. doi: 10.1242/jcs.122903. Epub 2013 Apr 16.
We demonstrate that c-Jun N-terminal kinase (JNK) responds to substrate stiffness and regulates adherens junction (AJ) formation in epithelial cells in 2D cultures and in 3D tissues in vitro and in vivo. Rigid substrates led to JNK activation and AJ disassembly, whereas soft matrices suppressed JNK activity leading to AJ formation. Expression of constitutively active JNK (MKK7-JNK1) induced AJ dissolution even on soft substrates, whereas JNK knockdown (using shJNK) induced AJ formation even on hard substrates. In human epidermis, basal cells expressed phosphorylated JNK but lacked AJ, whereas suprabasal keratinocytes contained strong AJ but lacked phosphorylated JNK. AJ formation was significantly impaired even in the upper suprabasal layers of bioengineered epidermis when prepared with stiffer scaffold or keratinocytes expressing MKK7-JNK1. By contrast, shJNK1 or shJNK2 epidermis exhibited strong AJ even in the basal layer. The results with bioengineered epidermis were in full agreement with the epidermis of jnk1(-/-) or jnk2(-/-) mice. In conclusion, we propose that JNK mediates the effects of substrate stiffness on AJ formation in 2D and 3D contexts in vitro as well as in vivo.
我们证明，c-Jun N 端激酶（JNK）对底物的刚性做出响应，并调节二维培养物中的上皮细胞和体外及体内三维组织中的黏着连接（AJ）的形成。刚性底物导致 JNK 激活和 AJ 解体，而软基质抑制 JNK 活性，导致 AJ 形成。组成性激活的 JNK（MKK7-JNK1）的表达甚至在软基质上诱导 AJ 溶解，而 JNK 敲低（使用 shJNK）则在硬基质上诱导 AJ 形成。在人类表皮中，基底细胞表达磷酸化的 JNK，但缺乏 AJ，而上皮细胞则含有强 AJ，但缺乏磷酸化的 JNK。即使在使用刚性支架或表达 MKK7-JNK1 的角质形成细胞制备的生物工程表皮的上层，AJ 的形成也受到显著损害。相比之下，shJNK1 或 shJNK2 表皮甚至在基底层也表现出强 AJ。生物工程表皮的结果与 jnk1(-/-)或 jnk2(-/-)小鼠的表皮完全一致。总之，我们提出 JNK 在体外和体内的二维和三维环境中，介导了底物刚性对 AJ 形成的影响。
