The role and molecular mechanisms of the early growth response 3 gene in schizophrenia.

Schizophrenia is a chronic, debilitating mental illness caused by both genetic and environmental factors. Genetic factors play a major role in schizophrenia development. Early growth response 3 (EGR3) is a member of the EGR family, which is associated with schizophrenia. Accumulating studies have investigated the relationship between EGR3 and schizophrenia. However, the role of EGR3 in schizophrenia pathogenesis remains unclear. In the present review, we focus on the progress of research related to the role of EGR3 in schizophrenia, including association studies between EGR3 and schizophrenia, abnormal gene expressional analysis of EGR3 in schizophrenia, biological function studies of EGR3 in schizophrenia, the molecular regulatory mechanism of EGR3 and schizophrenia susceptibility candidate genes, and possible role of EGR3 in the immune system function in schizophrenia. In summary, EGR3 is a schizophrenia risk candidate factor and has comprehensive regulatory roles in schizophrenia pathogenesis. Further studies investigating the molecular mechanisms of EGR3 in schizophrenia are warranted for understanding the pathophysiology of this disorder as well as the development of new therapeutic strategies for the treatment and control of this disorder.

Blood Lead and High-Density Lipoprotein Concentrations in Relation to Human Blood Pressure: A Cross Sectional Study.

Background: While the relationship between blood pressure and blood lead has been studied more extensively, the effect of high-density lipoprotein (HDL) concentration on this relationship remains uncertain. Therefore, this study aimed to determine the effect of HDL concentration on the relationship between blood lead and blood pressure. Methods: The research used cross-sectional data from the 2005 to 2014 National Health and Nutrition Examination Survey (NHANES), which included 16,451 participants aged 20-60 years. Multivariable linear regression was used to evaluate the correlation among blood lead, systolic blood pressure (SBP), and diastolic blood pressure (DBP). HDL concentration was determined by low HDL concentration (≤ 49 mg/dl) and high HDL concentration (>49 mg/dl) stratified. The effect of HDL concentration was assessed by an interaction test between blood lead and SBP in multivariable linear regression. Results: In this cross-sectional research, we identified a positive correlation between blood lead and SBP, but not DBP. The relationship between blood lead and SBP was different in the group with low and high HDL concentrations (ß: 0.21 95% Cl:-0.05-0.46 vs. ß:0.47 95% Cl: 0.15-0.79). In addition, high HDL significantly altered the positive correlation between blood lead and SBP (P-value of interaction < 0.001). Conclusion: The study suggests an interaction between HDL and blood lead in elevating SBP, which may have important clinical implications.

T-2 Toxin Induces Epiphyseal Plate Lesions via Decreased SECISBP2-Mediated Selenoprotein Expression in DA Rats, Exacerbated by Selenium Deficiency.

OBJECTIVE: Both selenium (Se) deficiency and mycotoxin T2 lead to epiphyseal plate lesions, similar to Kashin-Beck disease (KBD). However, regulation of selenoproteins synthesis mediated by SECISBP2, in response to these 2 environmental factors, remained unclear. The present study proposed to explore the mechanism behind the cartilage degradation resulting from Se deficiency and mycotoxin T2 exposure. DESIGN: Deep chondrocyte necrosis and epiphyseal plate lesions were replicated in Dark Agouti (DA) rats by feeding them T2 toxin/Se deficiency artificial synthetic diet for 2 months. RESULTS: Se deficiency led to decreased expression of COL2α1, while T2 treatment reduced the heparan sulfate 6-O-sulfotransferase 2 (HS6ST2) expression, both of which affected the cartilage extracellular matrix metabolism in the rat models. The expression of Col2α1, Acan, Hs6st2, Secisbp2, Gpx1, and Gpx4 were all significantly decreased in cartilage tissues from DA rats, fed a Se-deficient diet or exposed to T2 toxin, contrary to Adamts4, whose expression was increased in both conditions. In addition, T2 treatment led to the decreased expression of SBP2, GPX1, GPX4, and total GPXs activity in C28/I2 cells. CONCLUSION: DA rats exposed to T2 toxin and/or Se-deficient conditions serve as the perfect model of KBD. The 2 environmental risk factors of KBD, which serve as a "double whammy," can intensify the extracellular matrix metabolic imbalance and the antioxidant activity of chondrocytes, leading to articular cartilage degradation and epiphyseal plate abnormalities similar to those observed in KBD.

Selenium-sensitive miRNA-181a-5p targeting SBP2 regulates selenoproteins expression in cartilage.

Selenium (Se) deficiency brings about defects in the biosynthesis of several selenoproteins and has been associated with aberrant chondrogenesis. Selenocysteine (Sec) Insertion Sequence (SECIS) and SECIS binding protein 2 (SBP2) interaction is a very critical node for the metabolic balance between Se and selenoproteins. The Gpx1, Gpx4 and SelS have different binding affinities with SBP2 in cells. According to our results, both miR-181a-5p and SBP2 appeared to be selenium-sensitive and regulated the expression of selenoproteins in C28/I2 cells under Se sufficient environment. However, they showed significantly opposite expression trend in Se deficiency rats cartilage and SeD C28/I2 cells. The SBP2 is a direct target gene of miR-181a-5p in C28/I2 cells as determined by reporter gene and off-target experiments. And the miR-181a-5p could regulate SBP2 and the selenoproteins in C28/I2 cells. Depending upon the Se supply levels, C28/I2 cells were divided into three groups, that is normal Se, SeD and SeS, which underwent through a 7-day Se deprivation process, then SBP2 was knocked-down and overexpressed in all the groups. Moreover, the selected selenoproteins were down-regulated in second-generation low Se diet rat cartilage. The selenoproteins expression was decreased by Se deficiency which depended on the Selenium-sensitive miR-181a-5p to participate and regulate SBP2 at post-transcriptional level. It involves a series of antioxidant and ECM (extracellular matrix) genes, to overcome the ROS-related stress for the protection of essential physiological functions and to maintain the balance between anabolism and catabolism of the cartilage.

Abnormality of epiphyseal plate induced by selenium deficiency diet in two generation DA rats.

This study aimed to observe the effects of Se deficiency on epiphyseal plates of two generation DA rats fed with artificial total synthetic low Se diet. All F0 and F1 DA rats were fed with synthetic low Se diet (SeD group) and low Se diet supplied with Se (SeS group). The levels of selenium and enzyme activities of GPx were detected in plasma of the rats. General growth of bone and articular cartilage was measured macroscopically and microscopically. The epiphyseal plate of femur heads or tibia were obtained to histological and immunohistochemical examinations. The cartilage from left knee joints and femur heads was used to detect the gene expression of collagens, ADAMTSs and several selenoproteins by RT-qPCR. Two generation SeD rats showed Se insufficiency status. The thicknesses of the femur and tibial epiphyseal plates in both F0 and F1 SeD rats were significantly less than that of SeS rats. In F1 generation, SeD rats showed much fewer proliferative chondrocyte layers than SeS ones. Importantly, two generation SeD rats both showed significantly more serious pathological changes of epiphyseal plates. In two generation rats, gene expressions of COL II, GPx1 and GPx4 were significantly down-regulated in SeD rats than SeS ones; meanwhile ADAMTS-4 showed an up-regulated expression in cartilage. Dietary Se deficiency can apparently cause epiphyseal plate lesion and decrease cartilage type II collagen production and GPx1 activity in two generation DA rats fed with the artificial total synthesis low Se diet.

MicroRNAs associated with osteoarthritis differently expressed in bone matrix gelatin (BMG) rat model.

Osteoarthritis (OA) is characterized by degeneration of articular cartilage, limited intraarticular inflammation with synovitis, and changes in peri-articular and subchondral bone. In recent years, more and more evidence demonstrated that microRNAs (miRNAs) play important roles in the molecular mechanisms in OA by suppressing gene expression at the post-transcriptional level. In current study, histological staining of toluidine blue and cartilage-specific gene express revealed that the bone matrix gelatin (BMG) rat model could demonstrate the different development of cartilage. In current study, we tested whether some miRNAs associated with OA differently expressed in BMG rat model. We verified that miR-140 and miR-455 were associated with cartilage development, and further revealed that miR-140-5p and miR-455-3p might play more important function than miR-140-3p and miR-455-5p in the BMG rat model. Moreover, we found that miR-9 and miR-98 were involved in the endochondral ossification, suggesting they may be also the key regulators in the process of endochondral ossification. In fact, many miRNAs worked as a miRNA-mediated regulatory network in the process of cartilage development and OA. Further functional discovery will clarify the roles of individual miRNAs and their targets, and serve as a strong foundation for translating these findings to the clinic therapy for OA.

Down-regulation of miR-144 elicits proinflammatory cytokine production by targeting toll-like receptor 2 in nonalcoholic steatohepatitis of high-fat-diet-induced metabolic syndrome E3 rats.

OBJECTIVE: To analyze regulatory microRNA(s) leading to increased TLR2 expression in livers of high-fat-diet induced metabolic syndrome (HFD-MetS) in rats with non-alcoholic steatohepatitis (NASH). METHODS: TLRs, inflammatory cytokines, candidate miRNAs targeting key TLR and its cellular localization were determined in liver. The miR-144 targeting TLR2 and regulating TLR2 signaling were further determined by dual luciferase reporter assay and miR-144 mimics or inhibitor. RESULTS: Expression of miR-144 was negatively correlated with TLR2 expression in Kupffer cells. The miR-144 bound to 3'UTR of rat TLR2 mRNA. In addition, compared to control group, TLR2, TNF-α, IFN-γ and activation of NF-κB decreased after miR-144 mimic challenge in NR8383 cells and BMM from E3 rats, which could be compensated by Pam3CSK4; while opposite effects on their expressions were observed after miR-144 inhibitor administration, augmented by Pam3CSK4. CONCLUSION: Decreased miR-144 could enhance TNF-α and IFN-γ production by targeting TLR2 in vitro, and might contribute to TLR2 up-regulation and the progression of NASH in HFD-MetS E3 rats. This might offer a novel and potential target for NASH therapy.

MicroRNA-26a negatively regulates toll-like receptor 3 expression of rat macrophages and ameliorates pristane induced arthritis in rats.

INTRODUCTION: Abnormal toll-like receptor (TLR)3 signaling plays an indispensable role in pathogenesis of both experimental and human rheumatoid arthritis, and microRNAs (miRNAs) might orchestrate this signaling pathway. This study was performed to determine the relationship between miR-26a and TLR3 in rat macrophages and to observe effects of miR-26a mimic on pristane induced arthritis (PIA) in rats. METHODS: Dual luciferase reporter assay was used to validate the direct interaction between miR-26a (a candidate miRNA to target tlr3 mRNA) and tlr3 3'UTR. MiR-26a regulation on TLR3 gene expression was determined using RT-qPCR and Western blotting after miR-26a mimics and inhibitors were transfected into rat macrophage line NR8383 cells. Poly I:C (TLR3 ligand) was used to trigger TLR3 activation, and mRNA expression of its downstream cytokines interferon (ifn)-ß and tumor necrosis factor (tnf)-α was accordingly detected to determine the regulation of TLR3 signaling. Expressions of TLR3 and miR-26a were detected during rat bone marrow derived macrophage (BMDM) induction, in pristane stimulated NR8383 cells and spleens from methotrexate (MTX) treated PIA rats. A miR-26a mimic was administrated intraperitoneally to PIA rats, and arthritis severity was evaluated by macroscopic or microscopic observations. RESULTS: Direct target relationship between miR-26a and tlr3 mRNA in rats was confirmed. Modifications of miR-26a function by transfection of miR-26a mimics and inhibitors exhibited corresponding repression and augmentation of TLR3 and its signaling downstream cytokine expressions in NR8383 cells. The alteration of miR-26a expression was negatively related with TLR3 expression during BMDM induction, in pristane-primed NR8383 cells and PIA rat spleens. Moreover, both abnormal expressions were rescued in MTX treated arthritis rat spleens. The miR-26a mimic treatment displayed the depression of TLR3 expression and ameliorated the disease severity in the rats with pristane induced arthritis. CONCLUSIONS: MiR-26a negatively regulates TLR3 signaling via targeting of TLR3 itself in rat macrophages, and this finding provides a novel insight into abnormal TLR3 overexpression during experimental arthritis.

T-2 toxin enhances catabolic activity of hypertrophic chondrocytes through ROS-NF-κB-HIF-2α pathway.

T-2 toxin (T-2), one of the most important and toxic trichothecene mycotoxins, can cause many medical problems, such as diarrhea, nervous disorders, immunodepression and death, and is also believed as an etiological factor of Kashin-Beck disease, an endemic osteochondropathy prevailing in North China. However, the molecular mechanisms underlying T-2 effects on tissue damage remain elusive. We differentiated ATDC5 chondrogenic cells into hypertrophic chondrocytes, and found that T-2 reduced the expression of anabolic genes, and increased the expression of catabolic genes. To uncover the mechanism that T-2 influenced metabolic homeostasis of hypertrophic chondrocytes, we observed that T-2 increased the production of reactive oxygen species (ROS) and the degradation of IκB-α, and up-regulated the expression of hypoxia-induced factor-2α (HIF-2α). Bay11-7085 (an inhibitor of NF-κB pathway) inhibited the up-regulation of HIF-2α, and N-acetyl-l-cysteine (a ROS scavenger) inhibited both the decrease of IκB-α and the up-regulation of HIF-2α. Our results demonstrate that ROS-NF-κB-HIF-2α pathway participates in the effects of T-2 on hypertrophic chondrocytes, and HIF-2α plays an important role as a key mediator in this process.

Down-regulated HS6ST2 in osteoarthritis and Kashin-Beck disease inhibits cell viability and influences expression of the genes relevant to aggrecan metabolism of human chondrocytes.

OBJECTIVE: Primary OA and Kashin-Beck disease (KBD) show similar pathological changes in articular cartilage. The objective was to screen differentially expressed genes between OA and normal cartilage, confirm the candidate gene expression among OA, KBD and normal cartilage, and then clarify its role in vitro. METHODS: Differentially expressed genes in OA cartilage were screened by suppression subtractive hybridization (SSH) and verified by real-time quantitative PCR (Q-PCR) analysis. Heparan sulphate 6-O-sulphotransferase 2 (HS6ST2) expression was identified by Q-PCR and immunohistochemistry. After suppressing HS6ST2 by RNA interference in C28/I2 human chondrocyte line, the effects were analysed through determining the cell viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), the aggrecan contents by toluidine blue staining and the mRNA expression levels of SRY-type high mobility group box 9 (SOX9), AGC1, MMP3, a disintegrin and metalloproteinase domain with thrombospondin motifs 4 (ADAMTS4) and ADAMTS5 by Q-PCR. RESULTS: HS6ST2 in the reverse subtraction library was identified as a down-regulated gene in OA and KBD at both mRNA and protein levels. The percentage of safranion O staining area was correlated positively with the percentage of HS6ST2-positive chondrocytes in OA and KBD cartilage. After HS6ST2-specific short interfering RNA (siRNA) transfection to C28/I2 cells, the cell viability was inhibited significantly, and the mRNA expression levels of SOX9 and AGC1 were reduced markedly, while MMP3 expression was increased significantly. CONCLUSION; HS6ST2 down-regulation was identified in both OA and KBD cartilage. The findings first suggest that HS6ST2 may participate in the pathogenesis of OA and KBD by influencing aggrecan metabolism.

Autoimmune and inflammatory responses in Kashin-Beck disease compared with rheumatoid arthritis and osteoarthritis.

To examine plasma levels of arthritis-related autoantibodies and inflammatory factors in Kashin-Beck disease (KBD) patients compared with rheumatoid arthritis (RA) patients, osteoarthritis (OA) patients, and healthy controls, the plasma levels of autoantibodies to types II, IX, and XI collagen and cyclic citrullinated peptide (CCP) and immunoglobulin (Ig)-G and IgM rheumatoid factors (IgG-RF and IgM-RF) from 45 KBD patients, 39 RA patients, 46 OA patients, and 30 healthy controls were determined by enzyme-linked immunosorbent assay. The plasma concentrations of nitric oxide (NO) and tumor necrosis factor-α (TNF-α) were measured using the Griess method and bioassay, respectively. Statistical analysis was performed using one-way analysis of variance followed by the least significant difference t test for differences among groups. Results indicated that the plasma levels of collagen IX antibodies, IgG-RF, and NO significantly increased in KBD patients compared with patients with RA and OA and the control group. The levels of collagen XI antibodies, CCP antibodies, and IgM-RF but not collagen II antibodies and TNF-α were significantly increased in the plasma of the KBD group compared with that of the control group. We conclude that autoimmunity and inflammation may be involved in the pathogenesis of KBD, in particular in the advanced stage.

A novel replicated association between FXYD6 gene and schizophrenia.

FXYD6 gene is located in chromosome region 11q22-q24 where previous studies have shown an association with schizophrenia. However, the subsequent studies failed to replicate this finding. To investigate the relationship between FXYD6 locus and schizophrenia in Chinese population, we genotyped six single-nucleotide polymorphisms (SNPs) in this region of FXYD6 in 1142 Han Chinese subjects (576 cases and 566 controls), and performed an association analysis. Significant associations with schizophrenia and the marker rs11544201 (P=0.0028) and the haplotype rs10790212-rs11544201 (global P=0.005) were found. Our results support that FXYD6 is a susceptibility gene of schizophrenia. Replication of larger samples and functional analysis of FXYD6 are needed.

Is the EFNB2 locus associated with schizophrenia? Single nucleotide polymorphisms and haplotypes analysis.

Recently, evidence of linkage of schizophrenia to chromosome 13q22-q34 has been demonstrated in multiple studies. Based on structure and function, EFNB2 may be considered as a compelling candidate gene for schizophrenia on chromosome 13q33. We genotyped three single-nucleotide polymorphisms (SNPs: rs9520087, rs11069646, and rs8000078) in this region in 846 Han Chinese subjects (477 cases and 369 controls). Significant association between an allele of marker rs9520087 and schizophrenia was found. Furthermore, since no LD was observed in the three SNPs linkage disequilibrium estimation, all three SNPs were used in multiple SNPs haplotype analysis, and a strongly significant difference was found for the common haplotype TTC. Overall our findings indicate that EFNB2 gene may be a candidate susceptibility gene for schizophrenia in the Han Chinese population, and also provide further support for the potential importance of the NMDA receptor pathway in the etiology of schizophrenia.