Li Jia, Cao Rui, Wang Qian, Shi Hang, Wu Yi, Sun Kexin, Liu Xia, Jiang Haiyue
Plastic Surgery Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
J Tissue Eng Regen Med. 2022 Feb;16(2):188-199. doi: 10.1002/term.3271. Epub 2021 Dec 6.
Limitations of current treatments for auricular cartilage defects have prompted the field of auricular cartilage tissue engineering. To date, inducing the formation of cartilaginous constructs with biochemical and biomechanical properties of native tissue is the final aim. Through hematoxylin-eosin and immunohistochemistry staining, Cadherin-11(CDH11) was confirmed highly expressed in the auricular cartilage tissue and chondrocytes. In vitro, by knockdown and overexpression of CDH11 in chondrocytes, CDH11 was demonstrated to promote the expression of collagen type II (COL2A), elastin (ELN), aggrecan (ACAN), and cartilage oligomeric matrix protein (COMP). In addition, the CDH11 overexpressed chondrocytes promoted neo-cartilage formation and its biomechanical property by increasing the key transcription factor of chondrogenesis SOX9 expression and cartilage extracellular matrix (ECM) production. The young's modulus and yield stress of the neo-cartilage in CDH11 overexpression group were about 1.7 times (p = 0.0152) and 2 times (p = 0.0428) higher than those in control group, respectively. Then, the immunohistochemistry staining, qRT-PCR and western blot examination results showed that the expression of COL2A and ELN were significantly increased. Notably, the electron microscopy results showed that the collagen and elastic fibers of the neo-cartilage in CDH11-OV group arranged in bunches and were more uniform and compact compared to the control group. Furthermore, CDH11 promoted elastic fiber assembly by increasing lysyl oxidase (LOX), fibrillin-1 (FBN1) expression. Taken together, our results demonstrated that CDH11 improves the mechanical strength of tissue-engineered elastic cartilage by promoting ECM synthesis and elastic fiber assembly.
当前耳软骨缺损治疗方法的局限性推动了耳软骨组织工程领域的发展。迄今为止，诱导形成具有天然组织生化和生物力学特性的软骨构建体是最终目标。通过苏木精-伊红染色和免疫组织化学染色，证实钙黏蛋白-11（CDH11）在耳软骨组织和软骨细胞中高表达。在体外，通过敲低和过表达软骨细胞中的CDH11，证明CDH11可促进II型胶原蛋白（COL2A）、弹性蛋白（ELN）、聚集蛋白聚糖（ACAN）和软骨寡聚基质蛋白（COMP）的表达。此外，过表达CDH11的软骨细胞通过增加软骨形成关键转录因子SOX9的表达和软骨细胞外基质（ECM）的产生来促进新软骨形成及其生物力学性能。CDH11过表达组新软骨的杨氏模量和屈服应力分别比对照组高约1.7倍（p = 0.0152）和2倍（p = 0.0428）。然后，免疫组织化学染色、qRT-PCR和蛋白质印迹检测结果表明COL2A和ELN的表达显著增加。值得注意的是，电子显微镜结果表明，与对照组相比，CDH11过表达组新软骨的胶原纤维和弹性纤维成束排列，更加均匀和紧密。此外，CDH11通过增加赖氨酰氧化酶（LOX）、原纤蛋白-1（FBN1）的表达促进弹性纤维组装。综上所述，我们的结果表明，CDH11通过促进ECM合成和弹性纤维组装提高了组织工程弹性软骨的机械强度。
