Downregulation of the RNA-binding protein PUM2 facilitates MSC-driven bone regeneration and prevents OVX-induced bone loss

作者：Dong Suk Yoon, Yoorim Choi, Kyoungmi Lee, Eun Ae Ko, Eun‐Ji Kim, Kwang Hwan Park, Jin Woo Lee · 发表于：Journal of Biomedical Science · 年份：2023 · DOI：10.1186/s12929-023-00920-8 · 被引用次数：16 · 研究领域：RNA Research and Splicing、MicroRNA in disease regulation、Cancer-related molecular mechanisms research

BACKGROUND: Although mRNA dysregulation can induce changes in mesenchymal stem cell (MSC) homeostasis, the mechanisms by which post-transcriptional regulation influences MSC differentiation potential remain understudied. PUMILIO2 (PUM2) represses translation by binding target mRNAs in a sequence-specific manner. METHODS: In vitro osteogenic differentiation assays were conducted using human bone marrow-derived MSCs. Alkaline phosphatase and alizarin red S staining were used to evaluate the osteogenic potential of MSCs. A rat xenograft model featuring a calvarial defect to examine effects of MSC-driven bone regeneration. RNA-immunoprecipitation (RNA-IP) assay was used to determine the interaction between PUM2 protein and Distal-Less Homeobox 5 (DLX5) mRNA. Ovariectomized (OVX) mice were employed to evaluate the effect of gene therapy for postmenopausal osteoporosis. RESULTS: Here, we elucidated the molecular mechanism of PUM2 in MSC osteogenesis and evaluated the applicability of PUM2 knockdown (KD) as a potential cell-based or gene therapy. PUM2 level was downregulated during MSC osteogenic differentiation, and PUM2 KD enhanced MSC osteogenic potential. Following PUM2 KD, MSCs were transplanted onto calvarial defects in 12-week-old rats; after 8 weeks, transplanted MSCs promoted bone regeneration. PUM2 KD upregulated the expression of DLX5 mRNA and protein and the reporter activity of its 3'-untranslated region. RNA-IP revealed direct binding of PUM2 to DLX5 mRNA. We then eval...