Linc01776在椎间盘退行性变中生物学功能的研究

目的:椎间盘退行性变(intervertebral disc degeneration, IVDD)是中老年人中的高发病率与高致残率的疾病,目前其病理生理机制尚未完全研究清楚。本实验旨在研究linc01776在IVDD中的差异性表达,并通过生物信息学探索调控IVDD的分子学机制,从而为IVDD的治疗提供作用靶点。方法:根据Pffirrmann评分,将退变椎间盘标本分成对照组与IVDD组,通过qRT-PCR验证linc01776在退变椎间盘中的差异表达;构建Linc01776敲除质粒表达载体,并研究Linc01776在IVDD中生物功能学研究;预测Linc01776参与的竞争性内源RNA (CeRNA)调控机制。结果:linc01776在退变椎间盘中表达显著增加。敲除linc01776后,Aggrecan表达增加,MMP3、MMP13表达减少,细胞外基质分解降低。通过生物信息学预测Linc01776/miR-196b-5p/Akt1的CeRNA机制调控通路。结论:Linc01776促进髓核细胞外基质降解,调控IVDD的发生与发展。Linc01776/miR-196b-5p/Akt1信号轴可能为其调控IVDD进程的CeRNA机制调控通路。     

Sox9治疗兔椎间盘退变的效果及机制研究

目的:探究Sox9用于治疗椎间盘退变的效果及调控机制。方法:将Ad-sox9和Ad-GFP各20μL分别转染至椎间盘退变兔的髓核组织中,转染后3、7、30、60天取材,采用免疫组化、免疫荧光和MRI等研究方法检测椎间盘髓核组织中II型胶原、蛋白多糖的表达情况,并分析对椎间盘退变的改善情况。结果:免疫组化染色显示sox9组中椎间盘髓核组织中II型胶原、蛋白多糖的表达明显升高,MRI显示sox9组椎间盘T2像信号有明显改善(P<0.05)。结论:体内转染腺病毒介导的sox9基因能够增加椎间盘内II型胶原和蛋白多糖的表达,并抑制椎间盘的退变进程。     

Leptin Induces Cyclin D1 Expression and Proliferation of Human Nucleus Pulposus Cells via JAK/STAT,PI3K/Akt and MEK/ERK Pathways

Increasing evidence suggests that obesity and aberrant proliferation of nucleus pulposus (NP) cells are associated with intervertebral disc degeneration. Leptin, a hormone with increased circulating level in obesity, has been shown to stimulate cell proliferation in a tissue-dependent manner. Nevertheless, the effect of leptin on the proliferation of human NP cells has not yet been demonstrated. Here, we show that leptin induced the proliferation of primary cultured human NP cells, which expressed the leptin receptors OBRa and OBRb. Induction of NP cell proliferation was confirmed by CCK8 assay and immunocytochemistry and Real-time PCR for PCNA and Ki-67. Mechanistically, leptin induced the phosphorylation of STAT3, Akt and ERK1/2 accompanied by the upregulation of cyclin D1. Pharmacological inhibition of JAK/STAT3, PI3K/Akt or MEK/ERK signaling by AG490, Wortmannin or U0126, respectively, reduced leptin-induced cyclin D1 expression and NP cell proliferation. These experiments also revealed an intricate crosstalk among these signaling pathways in mediating the action of leptin. Taken together, we show that leptin induces human NP cell cyclin D1 expression and proliferation via activation of JAK/STAT3, PI3K/Akt or MEK/ERK signaling. Our findings may provide a novel molecular mechanism that explains the association between obesity and intervertebral disc degeneration.     

Calcitonin inhibits intervertebral disc degeneration by regulating protein kinase C

Intervertebral disc degeneration (IVDD) is the most critical factor that causes low back pain. Molecular biotherapy is a fundamental strategy for IVDD treatment. Calcitonin can promote the proliferation of chondrocytes, stimulate the synthesis of matrix and prevent cartilage degeneration. However, its effect and the underlying mechanism for IVDD have not been fully revealed. Chondrogenic specific matrix components’ mRNA expression of nucleus pulposus cell (NPC) was determined by qPCR. Protein expression of NPC matrix components and protein kinase C was determined by Western blotting. A rat caudal intervertebral disc degeneration model was established and tested for calcitonin in vivo. IL‐1 induced NPC change via decreasing protein kinase C (PKC)‐ε phosphorylation, while increasing PKC‐δ phosphorylation. Calcitonin treatment could prevent or reverse IL‐1‐induced cellular change on PKC signalling associated with degeneration. The positive effect of calcitonin on IVDD in vivo was verified on a rat caudal model. In summary, this study, for the first time, elucidated the important role of calcitonin in the regulation of matrix components in the nucleus of the intervertebral disc. Calcitonin can delay degeneration of the intervertebral disc nucleus by activating the PKC‐ε pathway and inhibiting the PKC‐δ pathway.     

Chondrocyte‐like nested cells in the aged intervertebral disc are late‐stage nucleus pulposus cells

Aging is a major risk factor of intervertebral disc degeneration and a leading cause of back pain. Pathological changes associated with disc degeneration include the absence of large, vacuolated and reticular‐shaped nucleus pulposus cells, and appearance of smaller cells nested in lacunae. These small nested cells are conventionally described as chondrocyte‐like cells; however, their origin in the intervertebral disc is unknown. Here, using a genetic mouse model and a fate mapping strategy, we have found that the chondrocyte‐like cells in degenerating intervertebral discs are, in fact, nucleus pulposus cells. With aging, the nucleus pulposus cells fuse their cell membranes to form the nested lacunae. Next, we characterized the expression of sonic hedgehog (SHH), crucial for the maintenance of nucleus pulposus cells, and found that as intervertebral discs age and degenerate, expression of SHH and its target Brachyury is gradually lost. The results indicate that the chondrocyte‐like phenotype represents a terminal stage of differentiation preceding loss of nucleus pulposus cells and disc collapse.     

退变腰椎间盘组织细胞凋亡相关蛋白酶Caspase-10 的表达研究

目的:探讨凋亡相关蛋白酶Caspase-10在腰椎间盘退变中的表达。方法:45例腰椎间盘突出症病人按年龄分为青年、中年和老年患者组,5例青少年型特发性脊柱侧弯病人作为对照组。患者组标本均为术中所取出L4/5新鲜椎间盘髓核组织,对照组标本均为术中所取出L2/3新鲜椎间盘髓核组织。采用TUNEL法和免疫组织化学S-P法,分别检测腰椎间盘髓核中的凋亡阳性细胞率及Caspase-10的表达情况。结果:对照组髓核内TUNEL阳性细胞率为(17.80±0.62)%。青年、中年、老年患者组髓核内TUNEL阳性细胞率分别为(45.71±2.05)%、(53.65±2.93)%和(68.39±4.33)%。四个组两两之间差异均有统计学意义(P<0.05)。对照组髓核内Caspase-10染色阳性细胞率为(32.60士1.64)%。青年、中年、老年患者组髓核内Caspase-10染色阳性细胞率分别为(50.67士2.89)%、(63.12士4.61)%和(75.28士4.26)%。四个组两两之间差异均有统计学意义(P<0.05)。髓核内Caspase-10染色阳性细胞率与TUNEL阳性细胞率和年龄之间均呈正相关(P<0.01)。结论:退行性变腰椎间盘组织中凋亡细胞率以及Caspase-10的表达均高于正常椎间盘组织,年龄是细胞凋亡的重要影响因素,细胞凋亡以及Caspase-10的表达上调可能在腰椎间盘退行性变的发生和发展中发挥重要作用。     

The role of TGF‐β1/Smad2/3 pathway in platelet‐rich plasma in retarding intervertebral disc degeneration

Recent studies have suggested that platelet‐rich plasma (PRP) injections are an effective way to retard intervertebral disc degeneration, but the mechanism of action is unclear. Activated platelets release some growth factors, such as transforming growth factor‐β1 (TGF‐β1), which positively modulate the extracellular matrix of nucleus pulposus cells. The purpose of this study was to explore the mechanism underlying the PRP‐mediated inhibition of intervertebral disc degeneration. In an in vitro study, we found that the proliferation of nucleus pulposus cells was greatly enhanced with 2.5% PRP treatment. The TGF‐β1 concentration was much higher after PRP treatment. PRP administration effectively increased the collagen II, aggrecan and sox‐9 mRNA levels and decreased collagen X levels. However, Western blotting demonstrated that specifically inhibiting TGF‐β1 signalling could significantly prevent nucleus pulpous cellular expression of Smad2/3 and matrix protein. In a rabbit study, magnetic resonance imaging revealed significant recovery signal intensity in the intervertebral discs of the PRP injection group compared with the very low signal intensity in the control groups. Histologically, the PRP plus inhibitor injection group had significantly lower expression levels of Smad2/3 and collagen II than the PRP group. These results demonstrated that a high TGF‐β1 content in the platelets retarded disc degeneration in vitro and in vivo. Inhibiting the TGF‐β1/Smad2/3 pathway could prevent this recovery by inactivating Smad2/3 and down‐regulating the extracellular matrix. Therefore, the TGF‐β1/Smad2/3 pathway might play a critical role in the ability of PRP to retard intervertebral disc degeneration.     

miR-155对人椎间盘退变髓核细胞凋亡的作用及机制研究

目的:探讨mi R-155对人椎间盘退变髓核细胞凋亡的影响及其作用机制。方法:首先构建慢病毒表达载体,在293T细胞中获得重组慢病毒,然后感染椎间盘退变髓核细胞得到稳定过表达细胞系,同时设置空载体和空白细胞组对照。用荧光显微镜观察慢病毒载体的标签蛋白GFP的表达,分别提取三组细胞总RNA,采用RT-q PCR方法检测mi R-155的表达;通过流式细胞术检测细胞凋亡,Western-Blot检测细胞中凋亡相关蛋白FADD、Caspase-3、Bcl-2及Bax的表达,JC-1试剂盒检测细胞线粒体膜电位的变化情况。结果:在荧光显微镜下,经慢病毒感染的过表达细胞系和空载体细胞系均出现绿色荧光,而空白细胞组未见绿色荧光;RT-qPCR结果显示构建的稳定过表达细胞系(GV369-miR-155-NP)中mi R-155的表达水平较高,且与空载体细胞系及空白细胞对照组均呈显著性差异(P0.05);与空载体组(GV369-NP)及空白细胞对照组相比,过表达组(GV369-miR-155-NP)细胞凋亡率显著降低(P0.05),FADD、Caspase-3、Bax的表达水平均明显下降,而Bcl-2表达水平显著增加(P0.05)。结论:mi R-155可能通过靶向结合Caspase-3和FADD阻止FasL-Fas途径或通过线粒体途径抑制人椎间盘退变髓核细胞凋亡。     

NF-κB信号通路参与高糖在椎间盘退行性变中影响及其作用的研究

目的:近来研究发现,椎间盘退变与代谢性疾病,尤其是与糖尿病具有明显的相关性,但具体机制尚未有深入研究。本实验拟探究高糖微环境诱导椎间盘退行性变及其对NF-κB信号通路的影响,为进一步揭示高糖诱导椎间盘髓核细胞退变的机制提供研究基础,为延缓、阻止糖尿病椎间盘退变和治疗糖尿病相关腰痛疾病带来新的策略和方法。方法:1、高糖微环境与IVDD的关系:使用5.5 mmol/L、15 mmol/L、30 mmol/L、100 mmol/L不同浓度葡萄糖培养基培养髓核细胞,RT-PCR检测髓核细胞MMP-3、MMP-13、Aggrecan、CollagenII的表达;2、NF-κB信号通路参与高糖微环境调控IVDD进展:Bay11-7082抑制NF-κB信号通路激活,再使用RT-PCR、Western Blot检测髓核细胞MMP-3、MMP-13、Aggrecan、CollagenII和NF-κB的表达。结果:RT-PCR检测显示,在不同葡萄糖浓度下,Aggrecan、CollagenII随浓度升高表达减少,MMP-3、MMP-13随浓度升高表达增加。RT-PCR、Western Blot检测显示,使用Bay11-7082可使高糖组中Aggrecan、CollagenII表达增加,MMP-3、MMP-13表达减少。结论:高糖微环境诱导椎间盘退行性变发病,且NF-κB信号通路参与高糖微环境诱导椎间盘退行性变发病。     

Exosomes miR-15a promotes nucleus pulposus-mesenchymal stem cells chondrogenic differentiation by targeting MMP-3

The physiology of the nucleus pulposus (NP) in intervertebral disc degeneration (IVD) has been studied widely. However, interactions involving nucleus pulposus -mesenchymal stem cells (NP-MSCs) are less understood. MicroRNA 15a (miR-15a) is known to target and modulate genes involved in cellular proliferation and apoptosis. This study aimed to understand the interactions and impact of miR-15a and NP-MSCs on chondrogenic differentiation and IVD degeneration. Exosomes secreted by NP cells were purified by differential centrifugation and identified by transmission electron microscopy and exosomal markers. Further, by co-culture these exosomes were re-introduced into the NP-MSC cells, which were confirmed by fluorescence confocal microscopy. NP-MSCs treated with exo-miR-15a increases aggrecan and collagen II mRNA and protein levels while decreasing mRNA and protein levels of ADAMTS4/5 and MMP-3/-13. Toluidine blue staining confirmed that chondrogenic differentiation was increased in NP-MSCs treated with exo-miR-15a. NP-MSCs treated with exo-anti-miR-15a inhibit aggrecan and collagen II expression while increasing ADAMTS4/5 and MMP-3/-13 expression and decreasing chondrogenic differentiation. Dual-luciferase reporter assays revealed that miR-15a directly targets MMP-3 and downregulates its expression. Overexpression of miR-15a increased proliferation and colony formation, whereas combinatorial overexpression with MMP3, suppressed miR-15a's effects. This was also evident through the decreased phosphorylation of PI3K and Akt, upregulation of Wnt3a and β-catenin in the presence of miR-15a, but overexpression of MMP3 indicated an opposite effect. Overall, these data demonstrate that exo-miR-15a promotes NP-MSCs chondrogenic differentiation by downregulating MMP-3 through PI3K/Akt and Wnt3a/β-catenin axis.     

缺氧诱导因子-1α和血管内皮生长因子在突出腰椎间盘中的表达及意义

目的探讨缺氧诱导因子-1α（hypoxia—induciblefactor-1α,HIF-1α）和血管内皮生长因子（vascular endothelial growth factor,VEGF）在突出腰椎间盘组织中的表达及意义。方法采用链霉亲和素-过氧化物酶复合物（SABC）免疫组化方法,测定40例腰椎间盘突出症患者椎间盘组织中HIF-1α和VEGF的表达情况。结果退变椎间盘组织中HIF-1α和VEGF呈高表达,HIF-1α和VEGF在髓核的表达显著高于纤维环;纤维环破裂型显著高于纤维环完整型;各组中HIF-1α和VEGF的表达均高度相关。结论HIF-1α和VEGF共同参与了椎间盘退变;HIF-1α可能通过上调VEGF的表达来促进椎间盘组织中新生血管的形成,进而延缓椎间盘退变的发生。     

MicroRNA-15b silencing inhibits IL-1β-induced extracellular matrix degradation by targeting SMAD3 in human nucleus pulposus cells

Objectives

To determine the role of microRNA-15b (miR-15b) in interleukin-1 beta (IL-1β)-induced extracellular matrix (ECM) degradation in the nucleus pulposus (NP).

Results

MiR-15b was up-regulated in degenerative NP tissues and in IL-1β-stimulated NP cells, as compared to the levels in normal controls (normal tissue specimens from patients with idiopathic scoliosis). Bioinformatics and luciferase activity analyses showed that mothers against decapentaplegic homolog 3 (SMAD3), a key mediator of the transforming growth factor-β signaling pathway, was directly targeted by miR-15b. Functional analysis demonstrated that miR-15b overexpression aggravated IL-1β-induced ECM degradation in NP cells, while miR-15b inhibition had the opposite effects. Prevention of IL-1β-induced NP ECM degeneration by the miR-15b inhibitor was attenuated by small-interfering-RNA-mediated knockdown of SMAD3. In addition, activation of MAP kinase and nuclear factor-κB up-regulated miR-15b expression and down-regulated SMAD3 expression in IL-1β-stimulated NP cells.

Conclusions

MiR-15b contributes to ECM degradation in intervertebral disc degeneration (IDD) via targeting of SMAD3, thus providing a novel therapeutic target for IDD treatment.

     

PeroxiredoxinⅡ在退变椎间盘髓核中的表达及其临床意义

目的：检测PeroxiredoxinⅡ在腰椎间盘髓核组织中的表达,分析其在椎间盘退变中的临床意义。方法：用蛋白免疫印迹（Western blot）的方法检测PeroxiredoxinⅡ在正常、突出及脱出腰椎间盘髓核中的表达情况。结果：PeroxiredoxinⅡ在退变椎间盘髓核中表达丰富,而在正常椎间盘髓核中表达微弱,两者比较差异显著（P〈0.05）,在突出和脱出椎间盘髓核中表达无显著性差异（P〉0.05）。结论：PeroxiredoxinⅡ在正常及退变腰椎间盘髓核组织中差异表达。     

Downregulation of microRNA-92b-3p suppresses proliferation,migration, and invasion of gastric cancer SGC-7901 cells by targeting Homeobox D10

To investigate the effect and mechanism of microRNA-92b-3p (miR-92b-3p) targeting Homeobox D10 (HOXD10) on proliferation, migration, and invasion of gastric cancer, we detected t he expression of miR-92b-3p and HOXD10 in SGC-7901 cells. The effects of miR-92b-3p or HOXD10 on proliferation, migration, invasion, and matrix metalloproteinase (MMP)-2/9 expression in SGC-7901 cells were measured by the Cell Counting Kit-8 assay, Transwell assay, and Western blot, respectively. The results showed that miR-92b-3p expression was increased, and HOXD10 expression was decreased in SGC-7901 cells, compared with human normal gastric epithelial cells GES-1. Functional experiments demonstrated that cell proliferation, migration, invasion, and expression of MMP-2/9 in SGC-7901 cells were significantly inhibited by miR-92b-3p silencing and HOXD10 overexpression. Moreover, HOXD10 was a potential target gene of miR-92b-3p as evidenced by the TargetScan software and double luciferase reporter assay. In the rescue experiment, knockdown of HOXD10, accompanied by higher expression of MMP-2/9, could significantly eliminate the inhibitory effects of miR-92b-3p silencing on cell proliferation, migration, and invasion. In conclusion, miR-92b-3p is highly expressed in gastric cancer SGC-7901 cells, and interfering with its expression might inhibit SGC-7901 cell proliferation, migration, and invasion via downregulating MMP-2/9 expression and targeting HOXD10.     

Versican G3 domain enhances cellular adhesion and proliferation of bovine intervertebral disc cells cultured in vitro

The functional role of versican in influencing intervertebral disc cell adhesion and proliferation was analyzed in bovine intervertebral disc. We have previously demonstrated the C-terminal globular G3 (or selectin-like) domain of versican to influence mesenchymal chondrogenesis and fibroblast proliferation in vitro. For this study, a versican G3 expression construct was generated to examine the role of the G3 domain of versican. Nucleus pulposus and annulus fibrosus cells were isolated from adult bovine caudal discs using sequential enzymatic digestion and versican expression characterized by RT-PCR. In cell proliferation assays, we observed that there was greater cellular proliferation in the presence of versican G3 for both disc cell types. The higher proliferation rate of annulus fibrosus cells when compared to nucleus pulposus cells seeded in monolayer supports heterogeneity of intervertebral disc cell populations. The presence of versican G3 construct enhanced the adhesion of isolated nucleus pulposus and annulus fibrosus cells approximately 4 to 6 fold, respectively. Cellular adhesion was greater in the presence of versican G3 in a dose dependent manner. G3 product was purified using affinity columns, and the purified G3 also enhanced cell adhesion.     

Increased expression of matrix metalloproteinase-10, nerve growth factor and substance P in the painful degenerate intervertebral disc

Introduction  

Matrix metalloproteinases (MMPs) are known to be involved in the degradation of the nucleus pulposus (NP) during intervertebral disc (IVD) degeneration. This study investigated MMP-10 (stromelysin-2) expression in the NP during IVD degeneration and correlated its expression with pro-inflammatory cytokines and molecules involved in innervation and nociception during degeneration which results in low back pain (LBP).     

A complex interaction between Wnt signaling and TNF-α in nucleus pulposus cells

Introduction

Increased expression of the proinflammatory cytokine TNF-α in intervertebral discs (IVDs) leads to inflammation, which results in progressive IVD degeneration. We have previously reported that activation of Wnt-β-catenin (hereafter called Wnt) signaling suppresses the proliferation of nucleus pulposus cells and induces cell senescence, suggesting that Wnt signaling triggers the process of degeneration of the IVD. However, it is not known whether cross talk between TNF-α and Wnt signaling plays a role in the regulation of nucleus pulposus cells. The goal of the present study was to examine the effect of the interaction between Wnt signaling and the proinflammatory cytokine TNF-α in nucleus pulposus cells.

Methods

Cells isolated from rat nucleus pulposus regions of IVDs were cultured in monolayers, and the expression and promoter activity of Wnt signaling and TNF-α were evaluated. We also examined whether the inhibition of Wnt signaling using cotransfection with Dickkopf (DKK) isoforms and Sclerostin (SOST) could block the effects of pathological TNF-α expression in nucleus pulposus cells.

Results

TNF-α stimulated the expression and promoter activity of Wnt signaling in nucleus pulposus cells. In addition, the activation of Wnt signaling by 6-bromoindirubin-3′-oxime (BIO), which is a selective inhibitor of glycogen synthase kinase 3 (GSK-3) activity that activates Wnt signaling, increased TNF-α expression and promoter activity. Conversely, the suppression of TNF-α promoter activity using a β-catenin small interfering RNA was evident. Moreover, transfection with DKK-3, DKK-4, or SOST, which are inhibitors of Wnt signaling, blocked Wnt signaling-mediated TNF-α activation; these effects were not observed for DKK-1 or DKK-2.

Conclusions

Here, we have demonstrated that Wnt signaling regulates TNF-α and that Wnt signaling and TNF-α form a positive-feedback loop in nucleus pulposus cells. The results of the present study provide in vitro evidence that activation of Wnt signaling upregulates the TNF-α expression and might cause the degeneration of nucleus pulposus cells. We speculate that blocking this pathway might protect nucleus pulposus cells against degeneration.