Abstract：
Osteoarthritis (OA) is a common joint disease known for cartilage degeneration, leading to a substantial burden on individuals and society due to its high disability rate. However, current clinical treatments for cartilage defects remain unsatisfactory due to the unclear mechanisms underlying cartilage regeneration. Tissue engineering hydrogels have emerged as an attractive approach in cartilage repair. Recent research studies have indicated that stem cells can sense the mechanical strength of hydrogels, thereby regulating their differentiation fate. In this study, we present the groundbreaking construction of dual-network DNA-silk fibroin (SF) hydrogels with controllable surface rigidity. The supramolecular networks, formed through DNA base-pairing, induce the development of β-sheet structures by constraining and aggregating SF molecules. Subsequently, SF was cross-linked via horseradish peroxidase (HRP)-mediated enzyme reactions to form the second network. Experimental results demonstrated a positive correlation between the surface rigidity of dual-network DNA-SF hydrogels and the DNA content. Interestingly, it was observed that dual-network DNA-SF hydrogels with moderate surface rigidity exhibited the highest effectiveness in facilitating the migration of bone marrow mesenchymal stem cells (BMSCs) and their chondrogenic differentiation. Transcriptome sequencing further confirmed that dual-network DNA-SF hydrogels primarily enhanced chondrogenic differentiation of BMSCs by upregulating the Wnt and TGF-β signaling pathways while accelerating collagen II synthesis. Furthermore, in vivo studies revealed that dual-network DNA-SF hydrogels with moderate surface rigidity significantly accelerated cartilage regeneration. In summary, the dual-network DNA-SF hydrogels represent a promising and novel therapeutic strategy for cartilage regeneration.
摘要：
骨关节炎（OA）是一种常见的关节疾病，以软骨退化而闻名，由于其高残疾率，给个人和社会带来了沉重负担。然而,由于软骨再生的潜在机制不明确,目前临床治疗软骨缺损的方法仍不尽人意.组织工程水凝胶已成为软骨修复中的一种有吸引力的方法。最近的研究表明，干细胞可以感知水凝胶的机械强度，从而调节他们的分化命运。在这项研究中,我们提出了具有可控表面刚度的双网络DNA-丝素蛋白（SF）水凝胶的开创性构建。超分子网络，通过DNA碱基配对形成的，通过约束和聚集SF分子诱导β-折叠结构的发展。随后，SF通过辣根过氧化物酶（HRP）介导的酶反应交联，形成第二个网络。实验结果表明，双网络DNA-SF水凝胶的表面刚度与DNA含量呈正相关。有趣的是,观察到具有中等表面硬度的双网络DNA-SF水凝胶在促进骨髓间充质干细胞（BMSCs）的迁移及其软骨分化方面表现出最高的有效性。转录组测序进一步证实，双网络DNA-SF水凝胶主要通过上调Wnt和TGF-β信号通路同时加速胶原蛋白II合成来增强BMSCs的软骨分化。此外，体内研究表明，具有中等表面刚度的双网络DNA-SF水凝胶可显着加速软骨再生。总之,双网络DNA-SF水凝胶代表了软骨再生的一种有前途和新颖的治疗策略。
