Department of Biomedical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, United States.
ACS Biomater Sci Eng. 2024 Oct 14;10(10):6545-6557. doi: 10.1021/acsbiomaterials.4c01100. Epub 2024 Sep 11.
Traumatic spinal cord injuries (SCI) are debilitating injuries affecting twenty-seven million people worldwide and cause functional impairments. Despite decades of research and medical advancements, current treatment options for SCI remain limited, in part due to the complex pathophysiology of spinal cord lesions including cellular transformation and extracellular matrix (ECM) remodeling. Recent studies have increased focus on fibrotic scarring after SCI, and yet much remains unclear about the impact of fibrotic scarring on SCI lesion progression. Here, using collagen and decellularized spinal cord-based composite hydrogels, a three-dimensional (3D) cell culture model mimicking the fibrous core of spinal cord lesions was implemented to investigate its influence on the surrounding astrocytes. To mimic the fibrotic milieu, collagen fibril thickness was tuned using previously established temperature-controlled casting methods. In our platforms, astrocytes in fibro-mimetic hydrogels exhibited increased levels of activation markers such as glial fibrillary acidic protein and N-cadherin. Furthermore, astrocytes in fibro-mimetic hydrogels deposited more fibronectin and laminin, further hinting that astrocytes may also contribute to fibrotic scarring. These markers were decreased when Rho-ROCK and integrin β1 were inhibited via pharmacological inhibitors. Mechanistic analysis of Yes-associated protein reveals that blocking integrin β1 prevents mechanosensing of astrocytes, contributing to altered phenotypes in variable culture conditions. In the presence of these inhibitors, astrocytes increased the secretion of brain-derived neurotrophic factor, and a greater degree of dorsal root ganglia neurite infiltration into the underlying hydrogels was observed. Altogether, this study presents a novel tissue-engineered platform to study fibrotic scarring after SCI and may be a useful platform to advance our understanding of SCI lesion aggravation.
创伤性脊髓损伤 (SCI) 是一种使人衰弱的损伤，影响全球 2700 万人，并导致功能障碍。尽管经过几十年的研究和医学进步，SCI 的治疗选择仍然有限，部分原因是脊髓损伤的复杂病理生理学，包括细胞转化和细胞外基质 (ECM) 重塑。最近的研究增加了对 SCI 后纤维化瘢痕的关注，但关于纤维化瘢痕对 SCI 病变进展的影响仍有许多不清楚的地方。在这里，使用胶原蛋白和去细胞化的脊髓基复合材料水凝胶，模拟脊髓损伤的纤维核心的三维 (3D) 细胞培养模型被实施，以研究其对周围星形胶质细胞的影响。为了模拟纤维化环境，使用先前建立的温度控制铸造方法来调整胶原蛋白纤维厚度。在我们的平台上，纤维模拟水凝胶中的星形胶质细胞表现出更高水平的激活标志物，如神经胶质纤维酸性蛋白和 N-钙黏蛋白。此外，纤维模拟水凝胶中的星形胶质细胞沉积了更多的纤连蛋白和层粘连蛋白，这进一步表明星形胶质细胞也可能有助于纤维化瘢痕的形成。当通过药理学抑制剂抑制 Rho-ROCK 和整合素 β1 时，这些标志物减少。Yes 相关蛋白的机制分析表明，阻断整合素 β1 可防止星形胶质细胞的机械感知，导致在不同培养条件下改变表型。在这些抑制剂的存在下，星形胶质细胞增加了脑源性神经营养因子的分泌，并且观察到更多的背根神经节神经突渗透到下面的水凝胶中。总的来说，这项研究提出了一种新的组织工程平台来研究 SCI 后的纤维化瘢痕，并且可能是一个有用的平台，可以促进我们对 SCI 病变加重的理解。
