This study investigated the role of miR-628-5p and interferon-induced protein 44-like (IFI44L) in osteosarcoma (OS) and determined whether miR-628-5p modulated OS growth by regulating IFI44L. Based on the data downloaded from Gene Expression Omnibus (GEO) database, we revealed that the expression of IFI44L was downregulated in OS and low expression of IFI44L was correlated with better prognosis of patients with OS. Biological prediction of its upstream regulatory miRNAs on the miRWalk website found that miR-628-5p is a possible upstream regulatory miRNA of IFI44L. Luciferase activity assay demonstrated that miR-628-5p could bind to the 3' untranslated region (UTR) of IFI44L, which proved the above prediction. The expression of miR-628-5p is upregulated in OS and high expression of miR-628-5p is correlated with poor prognosis of patients with OS. The results of RT-qPCR showed that the expression of miR-628-5p in MG-63, U2OS, Saos-2, and SW1353 cells was significantly higher than that in the hFOB1.19 cells. Downregulation of miR-628-5p by miR-628-5p inhibitor significantly inhibited the proliferation, migration, and invasion of MG-63 cells. By rescue assay, we found that knockdown of IFI44L rescued the proliferation and motility of miR-628-5p depleted MG-63 cells. Collectively, our present data illustrated that miR-628-5p promoted the growth and motility of OS at least partly by targeting IFI44L. Moreover, miR-628-5p and IFI44L might be proposed as promising biomarkers in OS diagnosis and treatment.

目的:探讨阶梯式手术治疗方案对腰椎间盘突出的临床疗效和患者对临床疗效的心理接受情况.方法:回顾性分析2014年至2016年本院骨科确诊为腰椎间盘突出症的50例患者,经椎间孔镜下行髓核摘除微创手术(Percutaneous transforaminal endoscopic discectomy,PTED),术后1天和3个月采用视觉疼痛模拟评分(VAS)和改良MacNab疗效评定、术后3个月采用Oswestry功能障碍指数(ODI)评价手术效果,以及相应调查时间点患者对手术效果心理接受程度调查;对于7例微创手术疗效不佳患者进一步采用传统的开窗髓核摘除术(Fenestration discectomy,FD),采用同样方法评价手术效果和调查患者心理接受情况.结果:50例微创术后1天及术后3个月的VAS评分和ODI指数均显著低于术前,差异具有显著性(P均＜0.05);改良MacNab疗效评定:术后1天优良率为84％,术后3个月为86％;患者对术后疗效心理满意度调查:术后1天,满意并接受为84％,不满意但接受为16％,不满意难接受为0;术后3个月,满意并接受为86％,不满意但接受为14％,不满意难接受为0.对于微创术后效果欠佳7例患者行FD手术,术后1天及3个月的VAS评分和ODI指数均显著低于术前,差异具有显著性(P均＜0.05);改良MacNab疗效评定:术后1天优良率为71％,术后3个月为100％;患者对开窗术后疗效心理满意度调查:术后1天,满意并接受为71％,不满意但接受为0,不满意难接受为29％;术后3个月,满意并接受为100％,不满意但接受为0,不满意难接受为0.结论:腰椎间盘突出症阶梯式手术治疗方案临床效果和患者心理接受情况均值得临床推荐.

目的:观察低强度超声波照射后组织工程骨的骨形成情况和力学变化.方法:将骨髓间充质细胞／β-磷酸三钙(Bone marrow stromal cells/tricalcium phosphate,BMSCs/β-TCP)共同增殖分化培养2周后,手术植入同基因鼠背部两侧皮下,一侧行低强度超声波每日照射20 min,另一侧作为对照.术后5、10、25和50d,分别取出组织工程骨,行抗压力测试、碱性磷酸酶(Alkaline phosphate,ALP)和骨钙素(osteocalcin,OCN)含量分析.结果:超声波组组织工程骨的ALP活性和OCN含量都明显高于对照组(P＜0.01);抗压力测试与对照组没有明显差别(P＞0.05).结论:低强度超声波能够促进组织工程骨的骨形成能力.

目的 观察低强度超声波照射后组织工程骨的骨形成情况和生物力学变化.方法 将骨髓间充质细胞/β-磷酸三钙(BMSCs/β-TCP)共同增殖分化培养2周后,手术植入同基因鼠背部两侧皮下,一侧行超声波照射20 min/d,另一侧作为对照.术后5、10、25和50 d,分别取出组织工程骨,行HE染色和CD31免疫组化染色,观察组织学变化.结果 组织学观察发现,超声波组组织工程骨较对照骨软组织修复、血运和血管形成更佳,骨形成更广泛.结论 低强度超声波能够促进组织工程骨内的血运和骨形成.

Background A practical problem impeding clinical translation is the limited bone formation seen in artificial bone grafts. Low-pressure/vacuum seeding and dynamic culturing in bioreactors have led to a greater penetration into the scaffolds, enhanced production of bone marrow cells, and improved tissue-engineered bone formation. The goal of this study was to promote more extensive bone formation in the composites of porous ceramics and bone marrow stromal cells (BMSCs). Methods BMSCs/β-tricalcium phosphate (β-TCP) composites were subcultured for 2 weeks and then subcutaneously implanted into syngeneic rats that were split into a low-intensity pulsed ultrasound (LIPUS) treatment group and a control group. These implants were harvested at 5, 10, 25, and 50 days after implantation. The samples were then biomechanically tested and analyzed for alkaline phosphate (ALP) activity and osteocalcin (OCN) content and were also observed by light microscopy. Results The levels of ALP activity and OCN content in the composites were significantly higher in the LIPUS group than in the control group. Histomorphometric analysis revealed a greater degree of soft tissue repair, increased blood flow, better angiogenesis, and more extensive bone formation in the LIPUS groups than in the controls. No significant difference in the compressive strength was found between the two groups. Conclusion LIPUS treatment appears to enhance bone formation and angiogenesis in the BMSCs/β-TCP composites. Chin Med J 2014;127 (4): 669-674

Although bone pain in osteoporosis and skeletal metastasis is an expected consequence of fracture, there are other underlying causes responsible. Our study demonstrated that ovarian cancer G-protein-coupled receptor 1 detected extracellular protons in MG63 cells, and regulated osteoblast functions, such as prostaglandin E2 production, in response to acidic circumstances. In this work, we measured inositol phosphate production, intracellular Ca(2+) concentration, prostaglandin E2 production, and cyclic adenosine monophosphate accumulation in MG63 cells exposed to extracellular acidification. Extracellular acidity induced a transient increase in Ca(2+) concentration and inositol phosphate production. Acidification also induced prostaglandin E2 production, resulting in cyclic adenosine monophosphate accumulation. A small interfering RNA specific for the ovarian cancer G-protein-coupled receptor 1 markedly inhibited these proton-induced actions in MG63 cells. These results indicated that the involvement of ovarian cancer G-protein-coupled receptor 1 in acidic extracellular environment may be an underlying mechanism responsible for bone pain in osteoporosis or bone metastasis without clinically proved fractures.

GPR4, previously proposed as the receptor for sphingosylphosphorylcholine, has recently been identified as the proton-sensing G-protein-coupled receptor coupling to multiple intracellular signaling pathways, including the Gs-protein/cAMP, G12/13-protein/Rho, and Gq-protein/phospholipase C pathways. In the present study, we examined whether extracellularly located histidine residues of GPR4 sense extracellular protons and, if so, whether a certain histidine residue is critical for coupling to the single or multiple signaling pathway(s). We found that the mutation of histidine residue at 79, 165, or 269 from the N-terminal of GPR4 to phenylalanine shifted the half-maximal effective concentration (EC50) of proton-induced signaling activities to the right, including cAMP accumulation, SRE promoter activity reflecting Rho activity, and NFAT promoter activity reflecting phospholipase C signaling activity, without an appreciable change in the maximal activities. These results suggest that the protonation of each one of histidine residues at 79, 165, and 269 in GPR4 may be critical for conformational change of the receptor for coupling to multiple intracellular signaling pathways through G-proteins.

Acidosis has been shown to induce depletion of bone calcium from the body. This calcium release process is thought to be partially cell mediated. In an organ culture of bone, acidic pH has been shown to induce cyclooxygenase-2 (COX-2) induction and prostaglandin E(2) (PGE(2)) production, resulting in stimulation of bone calcium release. However, the molecular mechanisms whereby osteoblasts sense acidic circumstances and thereby induce COX-2 induction and PGE(2) production remain unknown. In this study, we used a human osteoblastic cell line (NHOst) to characterize cellular activities, including inositol phosphate production, intracellular Ca(2+) concentration ([Ca(2+)](i)), PGE(2) production, and COX-2 mRNA and protein expression, in response to extracellular acidification. Small interfering RNA (siRNA) specific to the OGR1 receptor and specific inhibitors for intracellular signaling pathways were used to characterize acidification-induced cellular activities. We found that extracellular acidic pH induced a transient increase in [Ca(2+)](i) and inositol phosphate production in the cells. Acidification also induced COX-2 induction, resulting in PGE(2) production. These proton-induced actions were markedly inhibited by siRNA targeted for the OGR1 receptor and the inhibitors for G(q/11) protein, phospholipase C, and protein kinase C. We conclude that the OGR1/G(q/11)/phospholipase C/protein kinase C pathway regulates osteoblastic COX-2 induction and subsequent PGE(2) production in response to acidic circumstances.

GPR4 was initially identified as a receptor for sphingosylphosphorylcholine and lysophosphatidylcholine; however, lipid actions have not always been confirmed. Instead, ligand-independent actions have sometimes been observed in GPR4- and other OGR1 family receptor-expressing cells. Here, we examined the possible involvement of extracellular protons, which have recently been proposed as another ligand for GPR4. At pH 7.4, the epidermal growth factor-induced extracellular signal-regulated kinase activity was lower in GPR4-transfected RH7777 cells, in association with increased cAMP accumulation, than in vector-transfected cells. The serum response element (SRE)-driven transcriptional activity was also clearly higher in GPR4-expressing HEK293 cells than in vector-transfected cells at pH 7.4. These apparent ligand-independent actions were very small at alkalinic 7.8. The SRE activity was further increased by extracellular acidification in a manner dependent on the G13 protein/Rho signaling pathway in HEK293 cells expressing GPR4 or other OGR1 receptor family members. GPR4-expressing cells also showed a calcineurin-dependent nuclear factor of activated T cell (NFAT) promoter activation at pH 7.4, and this activity was further increased by pH below 7.2 in association with inositol phosphate production. In contrast to the cAMP and SRE responses, however, alkalinization to pH 7.8 hardly affected the high basal activity. Finally, the expression of GPR4 hardly modulated the sphingosylphosphorylcholine- or lysophosphatidylcholine-induced action. These results suggest that an extracellular proton play a role as a ligand in some of previously postulated ligand-independent actions through GPR4 receptors. Moreover, GPR4 may be a multi-functional receptor coupling to Gs, G13, and Gq/11 proteins in response to extracellular acidification.

目的:多孔生物材料中心部所存在的气泡有可能限制了细胞和培养液进入中心部,从而限制了材料内细胞的进一步增殖和分化,继而影响移植后的体内骨形成.实验设计使用低压方法排除多孔材料生物材料β-TCP内的气泡,检测细胞/β-TCP复合体的成骨能力,以验证其可行性.方法:实验于2003-04/2005-06在东京医科齿科大学医学部骨科实验室完成.在体外培养扩增骨髓间充质细胞后,将细胞置于成骨分化的培养液中,通过常压(大气压,101.1 kPa)和低压(13.3 kPa)两种方法将细胞灌注种植入72个多孔β-TCP人工骨中.细胞种植后检测β-TCP人工骨内含有的细胞悬浊液量,细胞生存率和细胞种植效率;应用扫描电镜观察细胞种植后人工骨内细胞附着情况.并在继续细胞分化培养1,2,3,4周时检测人工骨的DNA含量和碱性磷酸酶活性.结果:①低压组人工骨的细胞悬浊液量、全细胞种植效率和活细胞种植效率均高于常压组(P＜0.01);两种方法细胞种植后的细胞生存率没有明显不同(P＞0.05).②扫描电镜观察显示低压组人工骨内附着更多的骨髓间充质细胞.③低压组细胞分化培养过程中不同时点的人工骨碱性磷酸酶活性和DNA含量均高于常压组(P＜0.01).结论:13.3 kPa低压细胞灌注法可以明显提高多孔人工骨的细胞种植和成骨能力.低压细胞种植法是一个既简单方便又实用有效的方法.

The migration of vascular smooth muscle cells (SMCs) is a hallmark of the pathogenesis of atherosclerosis and restenosis after angioplasty. Plasma low-density lipoprotein (LDL), but not high-density lipoprotein (HDL), induced the migration of human coronary artery SMCs (CASMCs). Among bioactive lipids postulated to be present in LDL, lysophosphatidic acid (LPA) appreciably mimicked the LDL action. In fact, the LDL-induced migration was markedly inhibited by pertussis toxin, an LPA receptor antagonist Ki-16425, and a small interfering RNA (siRNA) targeted for LPA1 receptors. Moreover, LDL contains a higher amount of LPA than HDL does. HDL markedly inhibited LPA- and platelet-derived growth factor (PDGF)-induced migration, and sphingosine 1-phosphate (S1P), the content of which is about fourfold higher in HDL than in LDL, mimicked the HDL action. The inhibitory actions of HDL and S1P were suppressed by S1P2 receptor-specific siRNA. On the other hand, the degradation of the LPA component of LDL by monoglyceride lipase or the antagonism of LPA receptors by Ki-16425 allowed LDL to inhibit the PDGF-induced migration. The inhibitory effect of LDL was again Suppressed by S1P(2) receptor-specific siRNA. In conclusion, LPA/ LPA(1) receptors and S1P/S1P(2) receptors mediate the stimulatory and inhibitory migration response to LDL and HDL, respectively. The balance of not only the content of LPA and S1P in lipoproteins but also the signaling activity between LPA1 and S1P(2) receptors in the cells may be critical in determining whether the lipoprotein is a positive or negative regulator of CASMC migration.

Ovarian cancer G-protein-coupled receptor 1 (OGR1) and GPR4 have recently been identified as proton-sensing or extracellular pH-responsive G-protein-coupled receptors stimulating inositol phosphate production and cAMP accumulation, respectively. In the present study, we found that OGR1 and GPR4 mRNAs were expressed in human aortic smooth muscle cells (AoSMCs). Acidic extracellular pH induced inositol phosphate production, a transient increase in intracellular Ca(2+) concentration ([Ca(2+)](i)), and cAMP accumulation in these cells. When small interfering RNAs (siRNAs) targeted for OGR1 and GPR4 were transfected to the cells, the acid-induced inositol phosphate production and [Ca(2+)](i) increase were markedly inhibited by the OGR1 siRNA but not by the GPR4 siRNA. Unexpectedly, the acid-induced cAMP accumulation was also largely inhibited by OGR1 siRNA but only slightly by GPR4 siRNA. Acidic extracellular pH also stimulated prostaglandin I2 (PGI(2)) production, which was again inhibited by OGR1 siRNA. The specific inhibitors for extracellular signal-regulated kinase kinase and cyclooxygenase attenuated the acid-induced PGI(2) production and cAMP accumulation without changes in the inositol phosphate production. A specific inhibitor of phospholipase C also inhibited the acid-induced cAMP accumulation. In conclusion, OGR1 is a major receptor involved in the extracellular acid-induced stimulation of PGI(2) production and cAMP accumulation in AoSMCs. The cAMP accumulation may occur through OGR1-mediated stimulation of the phospholipase C/cyclooxygenase/PGI(2) pathway.

Ovarian cancer G-protein-coupled receptor 1 (OGR1), previously proposed as a receptor for sphingosylphosphorylcholine (SPC), has recently been identified as a proton-sensing or extracellular pH-responsive G-protein-coupled receptor stimulating inositol phosphate production, reflecting the activation of phospholipase C. In the present study, we found that acidic pH stimulated cAMP accumulation, reflecting the activation of adenylyl cyclase, in addition to inositol phosphate production in OGR1-expressing cells. The cAMP response was hardly affected by the inhibition of phospholipase C. SPC inhibited the acidification-induced actions in a pH-dependent manner, while no OGR1-dependent agonistic action of SPC was observed. Thus, the dose-response curves of the proton-induced actions were shifted to the right in the presence of SPC regardless of stereoisoform. The antagonistic property was also observed for psychosine and glucosylsphingosine. In conclusion, OGR1 stimulation may lead to the activation of adenylyl cyclase in addition to phospholipase C in response to extracellular acidification but not to SPC. However, SPC and related lysolipids antagonize the proton-induced and OGR1-mediated actions.

T cell death-associated gene 8 (TDAG8) has been reported to be a receptor for psychosine. Ovarian cancer G-protein-coupled receptor 1 (OGR1) and GPR4, G-protein-coupled receptors (GPCRs) closely related to TDAG8, however, have recently been identified as proton-sensing or extracellular pH-responsive GPCRs that stimulate inositol phosphate and cAMP production, respectively. In the present study, we examined whether TDAG8 senses extracellular pH change. In the several cell types that were transfected with TDAG8 cDNA, cAMP was markedly accumulated in response to neutral to acidic extracellular pH, with a peak response at approximately pH 7.0-6.5. The pH effect was inhibited by copper ions and was reduced or lost in cells expressing mutated TDAG8 in which histidine residues were changed to phenylalanine. In the membrane fractions prepared from TDAG8-transfected cells, guanosine 5'-O-(3-thiotriphosphate) binding activity and adenylyl cyclase activity were remarkably stimulated in response to neutral and acidic pH. The concentration-dependent effect of extracellular protons on cAMP accumulation was shifted to the right in the presence of psychosine. The inhibitory psychosine effect was also observed for pH-dependent actions in OGR1- and GPR4-expressing cells but not for prostaglandin E(2)- and sphingosine 1-phosphate-induced actions in any pH in native and sphingosine 1-phosphate receptor-expressing cells. Glucosylsphingosine and sphingosylphosphorylcholine similarly inhibited the pH-dependent action, although to a lesser extent. Psychosine-sensitive and pH-dependent cAMP accumulation was also observed in mouse thymocytes. We concluded that TDAG8 is one of the proton-sensing GPCRs coupling to adenylyl cyclase and psychosine, and its related lysosphingolipids behave as if they were antagonists against protein-sensing receptors, including TDAG8, GPR4, and OGR1.

The receptor-type protein tyrosine kinases in murine pancreatic islets were screened to identify possible growth/differentiation factors in pancreatic beta-cells. The analysis revealed that insulin receptor-related receptor (IRR) is highly expressed in the islets as well as in several highly differentiated beta-cell lines derived from transgenic mice. Islets predominantly contain IRR as uncleaved proreceptors compared with IRR as processed forms in the beta-cell lines, suggesting that the activity of IRR is regulated on the level of processing proteases in vivo. To examine the IRR signaling pathway, a chimeric receptor consisting of the extracellular domain of insulin receptor and the intracellular domain of IRR was expressed in Chinese hamster ovary cells. The hybrid receptor is functional because insulin is capable of tyrosine-phosphorylating the catalytic domain in these cells. It also stimulates the tyrosine phosphorylation of insulin receptor substrate (IRS)-1 and IRS-2, indicating that both proteins serve as substrates of IRR-protein tyrosine kinase in intact cells. The phenotype of the IRS-2 knockout mouse recently reported suggests that an IRS-2-mediated signaling pathway controls the compensatory increase in pancreatic beta-cell mass in insulin-resistant states. From our findings of the specific expression of IRR and its ability of signaling to IRS-2, we speculate that this receptor might play a role in the regulation of beta-cell mass.

A novel rabphilin-3-like gene, granuphilin, has been identified in pancreatic beta cells by comparing genes expressed in pancreatic alpha and beta cell lines using mRNA differential display. The domain structure of the protein products of the granuphilin gene contains an amino-terminal zinc-finger motif and carboxyl-terminal C2-domains, similar to that of the rabphilin-3 gene. There are two isoforms: the larger isoform, granuphilin-a, has two C2-domains, whereas the smaller one, granuphilin-b, contains only the first C2-domain. Granuphilin is specifically expressed in pancreatic beta cells and the pituitary gland, but not in pancreatic alpha cells, the adrenal gland, or other major organs such as the brain. A portion of granuphilin associates with insulin-containing dense-core granules, but not with synaptic-like microvesicles in beta cells. Thus, its distribution pattern presents a striking contrast with that of rabphilin-3, which associates with small synaptic vesicles in neurons. The first C2-domain of granuphilin binds phospholipids in a Ca2+-independent manner, whereas the second one does not. These distinctive characteristics of granuphilin suggest that it is not a simple counterpart of rabphilin-3 in endocrine cells and that it has a unique role in the regulated exocytosis of dense-core granules in endocrine tissues.