15-脂氧合酶-1 水平升高导致人类骨关节炎成骨细胞的异常表型。

Elevated levels of 15-lipoxygenase-1 contribute to the abnormal phenotypes of osteoblasts in human osteoarthritis.

机构信息

The First Affiliated Hospital of Anhui Medical University Department of Orthopedics, Jixi road 218, Hefei, 230022, PR China.

FuYang People's Hospital Department of Orthopedics, Sanqing road 501, Fuyang, 236000, PR China.

出版信息

Life Sci. 2019 Dec 15;239:116980. doi: 10.1016/j.lfs.2019.116980. Epub 2019 Nov 5.

DOI:10.1016/j.lfs.2019.116980

PMID:31704449

Abstract

AIMS

15-lipoxygenase-1 (15-LOX-1) plays a vital role in aggravating the inflammatory response in various pathological processes, including osteoarthritis (OA). Abnormal osteoblast phenotypes including elevated runt-related transcription factor 2 (RUNX2), collagen type 1 alpha 1 (COL1), and osteocalcin (OCN) lead to osteosclerosis of the subchondral bone, which eventually causes OA. However, the pathogenesis of OA is poorly defined, and it is unclear if 15-LOX-1 induces osteoblast abnormal phenotypes in OA. Therefore, this study aimed to determine the roles of 15-LOX-1 on the abnormal phenotypes present in osteoblasts of the subchondral bone in OA.

MAIN METHODS

The expression levels of 15-LOX-1 were measured by Immunohistochemistry, qRT-PCR and western blotting from the OA subchondral bone osteoblasts. To further investigate the roles of 15-LOX-1 in abnormal phenotypes of osteoblasts and its mechanisms in OA, 15-LOX-1 siRNA or overexpressing lv-15-lox-1 were transfected into osteoblasts, respectively. The effects of 15-LOX-1 on abnormal phenotypes of osteoblasts in OA were assessed by qRT-PCR, and western blotting. We also examined the role of 15-LOX-1-inhibited autophagy in OA osteoblasts by qRT-PCR, and western blotting, transmission electron microscopy.

KEY FINDINGS

The expression levels of 15-LOX-1 along with osteoblast phenotype markers such as RUNX2, COL1, and OCN were significantly increased in OA subchondral bone. Furthermore, 15-LOX-1 inhibited autophagy significantly upregulated the expression levels of RUNX2, COL1 and OCN through activated mTORC1. Similarly, treatment with autophagy inhibitors alleviated osteoblast abnormal phenotypes of osteoblasts in OA.

SIGNIFICANCE

In conclusion, our results suggested that the expression of 15-LOX-1 on osteoblasts from the subchondral bone increased in OA. 15-LOX-1 inhibited autophagy by activated mTORC1, which in turn upregulated the markers of abnormal osteoblast phenotypes RUNX2, COL1, and OCN.

摘要

目的

15-脂氧合酶-1（15-LOX-1）在各种病理过程中的炎症反应中起着至关重要的作用，包括骨关节炎（OA）。异常的成骨细胞表型，包括 runt 相关转录因子 2（RUNX2）、胶原 1 型α1（COL1）和骨钙素（OCN）的升高，导致软骨下骨的骨硬化，最终导致 OA。然而，OA 的发病机制尚不清楚，也不清楚 15-LOX-1 是否会诱导 OA 中成骨细胞的异常表型。因此，本研究旨在确定 15-LOX-1 在 OA 软骨下骨成骨细胞异常表型中的作用。

主要方法

通过免疫组织化学、qRT-PCR 和 Western blot 从 OA 软骨下骨成骨细胞中测量 15-LOX-1 的表达水平。为了进一步研究 15-LOX-1 在 OA 中成骨细胞异常表型中的作用及其机制，分别将 15-LOX-1 siRNA 或过表达 lv-15-lox-1 转染到成骨细胞中。通过 qRT-PCR 和 Western blot 评估 15-LOX-1 对 OA 中成骨细胞异常表型的影响。我们还通过 qRT-PCR 和 Western blot、透射电子显微镜检查了 15-LOX-1 抑制 OA 成骨细胞自噬的作用。

主要发现

OA 软骨下骨中 15-LOX-1 的表达水平以及成骨细胞表型标志物如 RUNX2、COL1 和 OCN 的表达水平均显著升高。此外，15-LOX-1 通过激活 mTORC1 显著抑制自噬，从而上调 RUNX2、COL1 和 OCN 的表达水平。同样，自噬抑制剂的治疗减轻了 OA 中成骨细胞的异常表型。