Cellular processes involve dynamic rearrangement of the cytoskeleton. The GTPase RhoA plays a fundamental role in controlling cytoskeletal architecture. The phenotypic stability of chondrocytes is enhanced through inhibition of RhoA, whereas RhoA activation leads to dedifferentiation. We hypothesized that local inhibition of this pathway could induce chondrogenesis and cartilage regeneration. In this study, a novel alginate-derived hydrogel system was developed for sustained RhoA targeting. Specifically, an engineered variant of C. botulinum C3 transferase, a potent RhoA inhibitor, was immobilized onto a hydrogel to achieve sustained release and enzymatic activity. Chondrocytes encapsulated within this fully biocompatible, mechanically stable scaffold produced a stable collagen type II-rich matrix in vitro which matured over a six-week period. Samples were implanted subcutaneously in mice, and similar production of a collagen type II-rich matrix was observed. The intrinsically versatile system has the potential to treat a number of clinical disorders, including osteoarthritis, linked with RhoA dysregulation.

中文翻译：

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靶向 RhoA 的细胞指导藻酸盐水凝胶

细胞过程涉及细胞骨架的动态重排。GTPase RhoA 在控制细胞骨架结构中起重要作用。软骨细胞的表型稳定性通过抑制 RhoA 得到增强，而 RhoA 激活导致去分化。我们假设该途径的局部抑制可以诱导软骨形成和软骨再生。在这项研究中，开发了一种新型藻酸盐衍生的水凝胶系统，用于持续的 RhoA 靶向。具体而言，将一种有效的 RhoA 抑制剂肉毒杆菌C3 转移酶的工程变体固定在水凝胶上以实现持续释放和酶活性。包裹在这种完全生物相容、机械稳定的支架内的软骨细胞产生了一种稳定的富含 II 型胶原蛋白的基质在六周内成熟的体外。将样品植入小鼠皮下，并观察到类似的富含 II 型胶原的基质的产生。本质上多功能的系统有可能治疗许多与 RhoA 失调有关的临床疾病，包括骨关节炎。