Septins超蛋白家族调控褪黑素介导成骨细胞内质网应激的研究

The relationship between melatonin and the occurrence and development of scoliosis (IS) is unclear.Our preliminary experiments revealed that melatonin has dual effects on osteoblast proliferation,depending on its concentration. Through the activation of CaMKs / MEK / ERK pathway , low concentration of melatonin promotes the proliferation of osteoblast, but the above mechanism is inhibited at high concentrations, while melatonin actives the membrane calcium ion channels, calcium influx causes calcium overload , and inhibites the proliferation of osteoblast.However melatonin suppression of osteoblast proliferation mechanism is unknown.Our study also found that melatonin suppression of osteoblast proliferation associated with Endoplasmic reticulum protein septins and endoplasmic reticulum stress. Thus, we speculate septins are the target of melatonin at osteoblasts. Through the reorganization at the plasma membrane, Septins regulate the STIM1-ORAI1 colocalization and calcium influx, cause calcium overload,induce the endoplasmic reticulum stress of osteoblasts, and inhibit the proliferation of osteoblasts by activating CHOP and Caspase-12 pathway.Basing on our previous studies and applying siRNA screen,patch clamp and RNA interference technology,we will further reveal the mechanism of Septins effects on melatonin-mediated osteoblasts endoplasmic reticulum stress in vivo and in vitro, thus providing new molecular targeted therapy for IS.

褪黑素与特发性脊柱侧凸（IS）的发生和发展关系尚不明确。我们前期发现褪黑素对成骨细胞增殖存在浓度依赖性，低浓度通过激活CaMKs/MEK/ERK通路，促进成骨细胞增殖；高浓度上述机制被抑制，同时激活细胞膜钙离子通道，引起钙超载，抑制成骨细胞增殖，但高浓度褪黑素抑制增殖的作用机制不明。我们前期及其他学者也发现，褪黑素抑制成骨细胞增殖与内质网膜上Septins和内质网应激相关。由此我们推测，Septins是高浓度褪黑素作用成骨细胞的靶点，通过在质膜上重组，调控STIM1/ORAI1共定位和钙离子浓度，引起钙超载，诱导成骨细胞内质网应激，激活CHOP和caspase-12通路,抑制成骨细胞增殖。本研究拟在我们前期研究基础上从在体和离体两方面，运用siRNA screen、膜片钳、RNA干预等技术手段，研究septins调控褪黑素介导成骨细胞内质网应激的作用机制,为IS分子水平治疗提供新途径。

褪黑素与特发性脊柱侧凸（IS）的发生和发展关系尚不明确。我们前期发现褪黑素对成骨细胞增殖存在浓度依赖性，低浓度通过激活CaMKs/MEK/ERK 通路，促进成骨细胞增殖；高浓度上述机制被抑制，但高浓度褪黑素抑制增殖的作用机制不明。我们前期及其他学者也发现，褪黑素抑制成骨细胞增殖与内质网膜上Septins 和内质网应激相关。经过实验证实，Septin4和7 是高浓度褪黑素作用成骨细胞的靶点，通过在质膜上重组，诱导成骨细胞内质网应激，激活CHOP 和caspase-12 通路,引起成骨细胞自噬，过度的自噬进而诱导成骨细胞凋亡。建立双足鼠对侧拴系脊柱侧凸模型，在动物水平验证septins 调控褪黑素介导成骨细胞内质网应激的作用机制,为IS 分子水平治疗提供新途径。