X Yu1, Y Qi2, T Zhao2, J Fang1, X Liu2, T Xu2, Q Yang2, X Dai3. 1. Department of Orthopaedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road 88#, Hangzhou 310009, PR China; Orthopaedics Research Institute, Zhejiang University, Jiefang Road 88#, Hangzhou, 310009, PR China; Department of Orthopaedic Surgery, Hangzhou Mingzhou Hospital (International Medical Center, Second Affiliated Hospital, Zhejiang University), Shixin Road 590#, Hangzhou 311215, PR China. 2. Department of Orthopaedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road 88#, Hangzhou 310009, PR China; Orthopaedics Research Institute, Zhejiang University, Jiefang Road 88#, Hangzhou, 310009, PR China. 3. Department of Orthopaedic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Jiefang Road 88#, Hangzhou 310009, PR China; Orthopaedics Research Institute, Zhejiang University, Jiefang Road 88#, Hangzhou, 310009, PR China. Electronic address: daixshz@zju.edu.cn.
Abstract
OBJECTIVE: Vascular invasion is observed at the osteochondral junction in osteoarthritis (OA). Nerve growth factor (NGF) as an angiogenic factor is expressed in OA. This study is to investigate the effects of NGF on angiogenesis in vitro in human chondrocytes. DESIGN: Articular cartilages of knee joints were harvested from healthy and OA patients. Expressions of NGF and tropomyosin-related kinase A (TrkA) were detected by western blot, Safranin-O and fast green staining and immunohistochemistry in cartilage. Expression of fibroblast growth factor 2 (FGF2) was detected by western blot in cultured chondrocytes. Chondrocytes were transfected by lentiviral vectors to knock down TrkA. Migration and tube formation of human microvascular endothelial cell (HMVEC) were assessed by using transwell co-culture with chondrocyte after treatment of NGF. RESULTS: We confirmed expressions of NGF and TrkA were significantly up-regulated in OA. NGF induced expression of FGF2 in a time- and dose-dependent manner. Angiogenic activities of endothelial cells were greatly enhanced after co-cultured with NGF pre-treated chondrocytes, while knock-down of TrkA significantly abolished the above effects. We further found that NGF-induced expression of FGF2 promoted angiogenic activities of endothelial cells through PI3K/Akt and ERK/MAPK signaling pathways. CONCLUSIONS: NGF promotes expression of FGF2 in vitro via PI3K/Akt and ERK/MAPK signaling pathways in human chondrocytes and it increases angiogenesis, which is mediated by TrkA. NGF could be responsible for vascular up-growth from subchondral bone in OA.
OBJECTIVE: Vascular invasion is observed at the osteochondral junction in osteoarthritis (OA). Nerve growth factor (NGF) as an angiogenic factor is expressed in OA. This study is to investigate the effects of NGF on angiogenesis in vitro in human chondrocytes. DESIGN: Articular cartilages of knee joints were harvested from healthy and OA patients. Expressions of NGF and tropomyosin-related kinase A (TrkA) were detected by western blot, Safranin-O and fast green staining and immunohistochemistry in cartilage. Expression of fibroblast growth factor 2 (FGF2) was detected by western blot in cultured chondrocytes. Chondrocytes were transfected by lentiviral vectors to knock down TrkA. Migration and tube formation of human microvascular endothelial cell (HMVEC) were assessed by using transwell co-culture with chondrocyte after treatment of NGF. RESULTS: We confirmed expressions of NGF and TrkA were significantly up-regulated in OA. NGF induced expression of FGF2 in a time- and dose-dependent manner. Angiogenic activities of endothelial cells were greatly enhanced after co-cultured with NGF pre-treated chondrocytes, while knock-down of TrkA significantly abolished the above effects. We further found that NGF-induced expression of FGF2 promoted angiogenic activities of endothelial cells through PI3K/Akt and ERK/MAPK signaling pathways. CONCLUSIONS:NGF promotes expression of FGF2 in vitro via PI3K/Akt and ERK/MAPK signaling pathways in human chondrocytes and it increases angiogenesis, which is mediated by TrkA. NGF could be responsible for vascular up-growth from subchondral bone in OA.
Authors: Haixin Song; Tao Wu; Xiaotian Yang; Yangzheng Li; Ye Ye; Bo Li; Tao Liu; Shihui Liu; Jianhua Li Journal: Stem Cells Int Date: 2021-04-24 Impact factor: 5.443
Authors: Wentian Zong; Mostafa Gouda; Enli Cai; Ruofeng Wang; Weijie Xu; Yuming Wu; Paulo E S Munekata; José M Lorenzo Journal: Molecules Date: 2021-12-09 Impact factor: 4.411