BackgroundLow back pain and sciatica caused by intervertebral disc (IVD) disease are associated with inflammatory responses. The cytokine interleukin 17 (IL-17) is elevated in herniated and degenerated IVD tissues and acts as a regulator of disc inflammation. The objective of this study was to investigate the involvement of IL-17A in IVD inflammatory response and to explore the mechanisms underlying this response.MethodsCells were isolated from nucleus pulposus (NP) tissues collected from patients undergoing surgeries for IVD degeneration. The concentrations of COX2 and PGE2, as well as of select proteins involved in the mitogen-activated protein kinase (MAPK)/activating protein-1 (AP-1) pathway, were quantified in NP cells after exposure to IL-17 with or without pretreatment with MAPK or AP-1 inhibitors.ResultsOur results showed that IL-17A increased COX2 expression and PGE2 production via the activation of MAPKs, including p38 kinase and Jun N-terminal kinase (JNK). Moreover, IL-17A-induced COX2 and PGE2 production was shown to rely on p38/c-Fos and JNK/c-Jun activation in an AP-1-dependent manner.ConclusionIn summary, our results indicate that IL-17A enhances COX2 expression and PGE2 production via the p38/c-Fos and JNK/c-Jun signalling pathways in NP cells to mediate IVD inflammation.

N-myc downstream-regulated gene 2 (NDRG2) is believed to be involved in cell growth events. However, its exact function is still unknown. To elucidate the role of this gene, we used an anti-Ndrg2 monoclonal antibody in immunohistochemistry and immunofluorescence assays to analyze the expression pattern of Ndrg2 protein in mouse embryos at various gestational ages and in a variety of adult mouse tissues. Ndrg2 immunoreactivity was generally localized to the cytoplasm. During mouse development, Ndrg2 expression was observed in many developing tissues and organs including the heart, brain, lung, gut, liver, kidney, skeletal muscle, cartilage, chorion, epidermis, and whisker follicles. Ndrg2 expression was developmentally dynamic, being generally lower in the early stages of development and markedly increasing during later stages. Ndrg2 expression was also observed in a variety of adult mouse tissues, particularly in the heart and brain. This is the first demonstration of Ndrg2 protein expression in both embryonic and adult mouse tissues. Our results suggest that NDRG2 plays important roles in histogenesis and organogenesis.

Regulation of matrix metalloproteinase-13 (MMP-13) by collagen matrix in the synovial fibroblasts of rheumatoid arthritis (RA) is critical event in the progressive joint destruction. Our previous study indicated that a collagen receptor, discoidin receptor 2 (DDR2), was highly expressed in the synovial fibroblasts of RA. However, the functional role of DDR2 in the regulation of MMP-13 production in synovial fibroblasts has not been elucidated. In this study, we initially demonstrated that the DDR2 and MMP-13 proteins are both highly expressed in the synovial lining layer of RA. MMP-13 mRNA and protein in synovial fibroblasts of RA were preferentially induced by collagen type II compared with MMP-1. Furthermore, stable overexpression of wild type DDR2 in murine synoviocytes dramatically augments the production of MMP-13. The activation of DDR2 also mediates the up-regulation of MMP-13 promoter activity in 293T cells. Inhibitor specific for extracellular signal-regulated kinase mitogen-activated protein kinase (ERK MAPK) cascade was shown to decrease MMP-13 level induced by collagen II in RA synovial fibroblasts and DDR2-induced MMP-13 promoter activity. Runx2 and activator protein-1 (AP-1) binding sites in MMP-13 promoter region are required for DDR2-induced transcription. The data in this study suggest that DDR2-mediated MMP-13 induction by collagen matrix in synovial fibroblasts of RA contributed to articular cartilage destruction.

BackgroundDeregulated thermal factors have been frequently implicated in the pathogenesis of male infertility, but the molecular basis through which certain responses are directed remain largely unknown. We previously reported that overexpression of exogenous Metastasis-associated protein 1 (MTA1) protects spermatogenic tumor cells GC-2spd (ts) against heat-induced apoptosis. To further dissect the underlying mechanism, we addressed here the fine coordination between MTA1 and p53 in pachytene spermatocytes upon hyperthermal stimulation.Methodology/Principal FindingsHigh level of MTA1 expression sustained for 1.5 h in primary spermatocytes after heat stress before a notable decrease was detected conversely correlated to the gradual increase of acetylation status of p53 and of p21 level. Knockdown of the endogenous MTA1 in GC-2spd (ts) elevated the acetylation of p53 by diminishing the recruitment of HDAC2 and thereafter led to a dramatic increase of apoptosis after heat treatment. Consistent with this, in vivo interference of MTA1 expression in the testes of C57BL/6 mice also urged an impairment of the differentiation of spermatocytes and a disruption of Sertoli cell function due to the elevated apoptotic rate after heat stress. Finally, attenuated expression of MTA1 of pachytene spermatocytes was observed in arrested testes (at the round spermatid level) of human varicocele patients.ConclusionsThese data underscore a transient protective effect of this histone modifier in primary spermatocytes against heat-stress, which may operate as a negative coregulator of p53 in maintenance of apoptotic balance during early phase after hyperthermal stress.

BackgroundEarly-onset scoliosis (EOS), defined by an onset age of scoliosis less than 10 years, conveys significant health risk to affected children. Identification of the molecular aetiology underlying patients with EOS could provide valuable information for both clinical management and prenatal screening.MethodsIn this study, we consecutively recruited a cohort of 447 Chinese patients with operative EOS. We performed exome sequencing (ES) screening on these individuals and their available family members (totaling 670 subjects). Another cohort of 13 patients with idiopathic early-onset scoliosis (IEOS) from the USA who underwent ES was also recruited.ResultsAfter ES data processing and variant interpretation, we detected molecular diagnostic variants in 92 out of 447 (20.6%) Chinese patients with EOS, including 8 patients with molecular confirmation of their clinical diagnosis and 84 patients with molecular diagnoses of previously unrecognised diseases underlying scoliosis. One out of 13 patients with IEOS from the US cohort was molecularly diagnosed. The age at presentation, the number of organ systems involved and the Cobb angle were the three top features predictive of a molecular diagnosis.ConclusionES enabled the molecular diagnosis/classification of patients with EOS. Specific clinical features/feature pairs are able to indicate the likelihood of gaining a molecular diagnosis through ES.