Division of Rheumatology & Immunology, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA.
Departments of Comparative Medicine and Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, USA.
Int J Mol Sci. 2020 Dec 30;22(1):335. doi: 10.3390/ijms22010335.
Pulmonary fibrosis is one of the important causes of morbidity and mortality in fibroproliferative disorders such as systemic sclerosis (SSc) and idiopathic pulmonary fibrosis (IPF). Insulin-like growth factor binding protein-5 (IGFBP-5) is a conserved member of the IGFBP family of proteins that is overexpressed in SSc and IPF lung tissues. In this study, we investigated the functional role of IGFBP-5 in the development of fibrosis in vivo using a transgenic model. We generated transgenic mice ubiquitously expressing human IGFBP-5 using CRISPR/Cas9 knock-in. Our data show that the heterozygous and homozygous mice are viable and express human IGFBP-5 (h). Transgenic mice had increased expression of extracellular matrix (ECM) genes, especially , and in lung and skin tissues of mice expressing higher transgene levels. Histologic analysis of the skin tissues showed increased dermal thickness, and the lung histology showed subtle changes in the heterozygous and homozygous mice as compared with the wild-type mice. These changes were more pronounced in animals expressing higher levels of h. Bleomycin increased ECM gene expression in wild-type mice and accentuated an increase in ECM gene expression in transgenic mice, suggesting that transgene expression exacerbated bleomycin-induced pulmonary fibrosis. Primary lung fibroblasts cultured from lung tissues of homozygous transgenic mice showed significant increases in ECM gene expression and protein levels, further supporting the observation that IGFBP-5 resulted in a fibrotic phenotype in fibroblasts. In summary, transgenic mice expressing human IGFBP-5 could serve as a useful animal model for examining the function of IGFBP-5 in vivo.
肺纤维化是系统性硬化症（SSc）和特发性肺纤维化（IPF）等纤维增生性疾病导致发病率和死亡率的重要原因之一。胰岛素样生长因子结合蛋白-5（IGFBP-5）是 IGFBP 蛋白家族中的一个保守成员，在 SSc 和 IPF 肺组织中过度表达。在这项研究中，我们使用转基因模型研究了 IGFBP-5 在体内纤维化发展中的功能作用。我们使用 CRISPR/Cas9 基因敲入技术在体内生成了普遍表达人 IGFBP-5 的转基因小鼠。我们的数据表明，杂合子和纯合子小鼠均具有活力，并表达人 IGFBP-5（h）。转基因小鼠的细胞外基质（ECM）基因表达增加，特别是在肺和皮肤组织中，表达更高转基因水平的小鼠的基因表达更高。皮肤组织的组织学分析显示真皮厚度增加，与野生型小鼠相比，杂合子和纯合子小鼠的肺组织学显示出细微变化。在表达更高水平 h 的动物中，这些变化更为明显。博来霉素增加了野生型小鼠的 ECM 基因表达，并加重了转基因小鼠 ECM 基因表达的增加，表明转基因表达加剧了博来霉素诱导的肺纤维化。从纯合子转基因小鼠的肺组织中培养的原代肺成纤维细胞显示 ECM 基因表达和蛋白水平显著增加，进一步支持 IGFBP-5 导致成纤维细胞纤维化表型的观察结果。总之，表达人 IGFBP-5 的转基因小鼠可以作为研究 IGFBP-5 在体内功能的有用动物模型。
