Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel; Procore Ltd., Weizmann Science Park, 7 Golda Meir St., P.O. Box 4082, Ness Ziona 7414002, Israel.
AO Research Institute, Davos, Switzerland; Department of Orthopedics, Erasmus MC, University Medical Center, CN Rotterdam, the Netherlands.
Acta Biomater. 2020 Mar 15;105:170-179. doi: 10.1016/j.actbio.2020.01.032. Epub 2020 Jan 23.
Current treatments for cartilage lesions are often associated with fibrocartilage formation and donor site morbidity. Mechanical and biochemical stimuli play an important role in hyaline cartilage formation. Biocompatible scaffolds capable of transducing mechanical loads and delivering bioactive instructive factors may better support cartilage regeneration. In this study we aimed to test the interplay between mechanical and FGF-18 mediated biochemical signals on the proliferation and differentiation of primary bovine articular chondrocytes embedded in a chondro-conductive Fibrin-Hyaluronan (FB/HA) based hydrogel. Chondrocytes seeded in a Fibrin-HA hydrogel, with or without a chondro-inductive, FGFR3 selective FGF18 variant (FGF-18v) were loaded into a joint-mimicking bioreactor applying controlled, multi-axial movements, simulating the natural movements of articular joints. Samples were evaluated for DNA content, sulphated glycosaminoglycan (sGAG) accumulation, key chondrogenic gene expression markers and histology. Under moderate loading, samples produced particularly significant amounts of sGAG/DNA compared to unloaded controls. Interestingly there was no significant effect of FGF-18v on cartilage gene expression at rest. Following moderate multi-axial loading, FGF-18v upregulated the expression of Aggrecan (ACAN), Cartilage Oligomeric Matrix Protein (COMP), type II collagen (COL2) and Lubricin (PRG4). Moreover, the combination of load and FGF-18v, significantly downregulated Matrix Metalloproteinase-9 (MMP-9) and Matrix Metaloproteinase-13 (MMP-13), two of the most important factors contributing to joint destruction in OA. Biomimetic mechanical signals and FGF-18 may work in concert to support hyaline cartilage regeneration and repair. STATEMENT OF SIGNIFICANCE: Articular cartilage has very limited repair potential and focal cartilage lesions constitute a challenge for current standard clinical procedures. The aim of the present research was to explore novel procedures and constructs, based on biomaterials and biomechanical algorithms that can better mimic joints mechanical and biochemical stimulation to promote regeneration of damaged cartilage. Using a hydrogel-based platform for chondrocyte 3D culture revealed a synergy between mechanical forces and growth factors. Exploring the mechanisms underlying this mechano-biochemical interplay may enhance our understanding of cartilage remodeling and the development of new strategies for cartilage repair and regeneration.
目前治疗软骨损伤的方法往往与纤维软骨形成和供体部位发病率有关。机械和生化刺激在透明软骨形成中起着重要作用。能够传递机械负荷并传递生物活性指导因子的生物相容性支架可能更有利于软骨再生。本研究旨在测试机械和 FGF-18 介导的生化信号在原代牛关节软骨细胞增殖和分化中的相互作用，这些细胞被嵌入软骨传导纤维蛋白-透明质酸（FB/HA）水凝胶中。将种子细胞接种到纤维蛋白-透明质酸水凝胶中，无论是否含有软骨诱导的 FGFR3 选择性 FGF18 变体（FGF-18v），都可以将其装入关节模拟生物反应器中，应用控制的多轴运动，模拟关节的自然运动。评估样本的 DNA 含量、硫酸化糖胺聚糖（sGAG）积累、关键软骨生成基因表达标志物和组织学。在适度加载下，与未加载对照相比，样本产生了特别大量的 sGAG/DNA。有趣的是，在静止状态下，FGF-18v 对软骨基因表达没有显著影响。在适度的多轴加载后，FGF-18v 上调了聚集蛋白（ACAN）、软骨寡聚基质蛋白（COMP）、II 型胶原（COL2）和润滑素（PRG4）的表达。此外，负荷和 FGF-18v 的组合，显著下调了基质金属蛋白酶-9（MMP-9）和基质金属蛋白酶-13（MMP-13）的表达，这两种酶是 OA 中导致关节破坏的最重要因素之一。仿生机械信号和 FGF-18 可能协同作用，支持透明软骨再生和修复。意义声明：关节软骨的修复潜力非常有限，局灶性软骨损伤是当前标准临床程序的挑战。本研究旨在探索基于生物材料和生物力学算法的新型程序和构建体，这些算法可以更好地模拟关节的机械和生化刺激，以促进受损软骨的再生。使用基于水凝胶的软骨细胞 3D 培养平台揭示了机械力和生长因子之间的协同作用。探索这种机械-生化相互作用的机制可能会增强我们对软骨重塑的理解，并为软骨修复和再生开发新策略。
