Department of Spine Surgery, Xiangya Hospital, Central South University, No. 87, Xiangya Road, Changsha, 410008, China.
Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, 410008, China.
Biochem Biophys Res Commun. 2019 Oct 15;518(2):259-265. doi: 10.1016/j.bbrc.2019.08.044. Epub 2019 Aug 14.
Adolescent idiopathic scoliosis (AIS) is a severe spinal deformity that often occurs during puberty. The occurrence of AIS is suggested to be related to abnormal development of cartilage. Our previous study found increased serum ghrelin levels in AIS patients that may linked to the development of AIS. However, whether ghrelin affects cartilage in AIS patients is unclear. We used quantitative real-time PCR (qRT-PCR) and immunohistochemistry to detect the expression of cartilage-specific genes and the ghrelin receptor, growth hormone secretagogue receptor (GHSR). The mRNA and protein levels of collagen II (COLII), SOX9, AGGRECAN (ACAN) and GHSR were higher in AIS patients than in controls. In addition, the protein levels of GHSR downstream signaling pathway members p-STAT3 (Ser727), and p-ERK1/2 were increased. Furthermore, we treated chondrocytes from AIS patients with 100 nM ghrelin, the cell proliferation assay and Western blotting showed that ghrelin promotes chondrocyte proliferation and enhances COLII, SOX9, ACAN, p-ERK1/2 and p-STAT3 expression, respectively. Interestingly, all these observed alterations were abolished by ghrelin + [D-Lys3]-GHRP-6 (a ghrelin receptor inhibitor) treatment. And after U0126 (an inhibitor of ERK1/2 phosphorylation) treatment, ERK1/2 and STAT3 (Ser727) phosphorylation was simultaneously suppressed indicating that ERK1/2 is an upstream pathway protein of STAT3 (Ser727). In conclusion, ghrelin plays an important role in upregulating cartilage-specific genes on AIS primary chondrocytes by activating ERK/STAT3 signaling pathway.
青少年特发性脊柱侧凸（AIS）是一种严重的脊柱畸形，常在青春期发生。AIS 的发生被认为与软骨的异常发育有关。我们之前的研究发现 AIS 患者的血清胃饥饿素水平升高，这可能与 AIS 的发生有关。然而，胃饥饿素是否影响 AIS 患者的软骨尚不清楚。我们使用定量实时 PCR（qRT-PCR）和免疫组织化学检测软骨特异性基因和胃饥饿素受体、生长激素释放肽受体（GHSR）的表达。与对照组相比，AIS 患者的 COLII、SOX9、ACAN 和 GHSR 的 mRNA 和蛋白水平更高。此外，GHSR 下游信号通路成员 p-STAT3（Ser727）和 p-ERK1/2 的蛋白水平增加。此外，我们用 100 nM 胃饥饿素处理 AIS 患者的软骨细胞，细胞增殖试验和 Western blot 显示，胃饥饿素促进软骨细胞增殖，并分别增强 COLII、SOX9、ACAN、p-ERK1/2 和 p-STAT3 的表达。有趣的是，所有这些观察到的变化都被胃饥饿素+[D-Lys3]-GHRP-6（胃饥饿素受体抑制剂）处理所消除。并且在用 U0126（ERK1/2 磷酸化抑制剂）处理后，ERK1/2 和 STAT3（Ser727）磷酸化同时被抑制，表明 ERK1/2 是 STAT3（Ser727）的上游通路蛋白。总之，胃饥饿素通过激活 ERK/STAT3 信号通路在 AIS 原代软骨细胞中上调软骨特异性基因，发挥重要作用。
