Ciliary parathyroid hormone signaling activates transforming growth factor-β to maintain intervertebral disc homeostasis during aging

© 2018 The Author(s). Degenerative disc disease (DDD) is associated with intervertebral disc degeneration of spinal instability. Here, we report that the cilia of nucleus pulposus (NP) cells mediate mechanotransduction to maintain anabolic activity in the discs. We found that mechanical stress promotes transport of parathyroid hormone 1 receptor (PTH1R) to the cilia and enhances parathyroid hormone (PTH) signaling in NP cells. PTH induces transcription of integrin αvβ6 to activate the transforming growth factor (TGF)-β-connective tissue growth factor (CCN2)-matrix proteins signaling cascade. Intermittent injection of PTH (iPTH) effectively attenuates disc degeneration of aged mice by direct signaling through NP cells, specifically improving intervertebral disc height and volume by increasing levels of TGF-β activity, CCN2, and aggrecan. PTH1R is expressed in both mouse and human NP cells. Importantly, knockout PTH1R or cilia in the NP cells results in significant disc degeneration and blunts the effect of PTH on attenuation of aged discs. Thus, mechanical stress-induced transport of PTH1R to the cilia enhances PTH signaling, which helps maintain intervertebral disc homeostasis, particularly during aging, indicating therapeutic potential of iPTH for DDD

EZH2 Mediates miR-146a-5p/HIF-1α to Alleviate Inflammation and Glycolysis after Acute Spinal Cord Injury

Acute spinal cord injury (ASCI) is a severe traumatic disease of the central nervous system, the underlying mechanism of which is unclear. This study was intended to study the role of EZH2 and miR-146a-5p/HIF-1α in inflammation and glycolysis after ASCI, providing reference and basis for the clinical treatment and prognosis of ASCI injury. We used lipopolysaccharide (LPS) to induce inflammation of microglia, and we constructed the ASCI animal model. qRT-PCR detected the relative expression levels of EZH2, HIF-1α, miR-146a-5p, IL-6, TNF-α, IL-17, PKM2, GLUT1, and HK2 in cells and tissues. Western blot was performed to detect the expression levels of EZH2, HIF-1α, H3K27me3, IL-6, TNF-α, IL-17, PKM2, GLUT1, and HK2. ChIP verified the enrichment of H3K27me3 in the miR-146a-5p promoter region. Bioinformatics predicted the binding sites of HIF-1α and miR-146a-5p, and dual-luciferase reporter assay verified the binding of HIF-1α and miR-146a-5p. ELISA detects the levels of inflammatory factors IL-6, TNF-α, and IL-17 in the cerebrospinal fluid of rats. The GC-TOFMS was used to detect the changes of glycolytic metabolites in the cerebrospinal fluid of rats. EZH2 could mediate inflammation and glycolysis of microglia. EZH2 regulates inflammation and glycolysis through HIF-1α. EZH2 indirectly regulated the HIF-1α expression by mediating miR-146a-5p. EZH2 mediates miR-146a-5p/HIF-1α to alleviate inflammation and glycolysis in ASCI rats. In the present study, our results demonstrated that EZH2 could mediate miR-146a-5p/HIF-1α to alleviate the inflammation and glycolysis after ASCI. Therefore, EZH2/miR-146a-5p/HIF-1α might be a novel potential target for treating ASCI

Anti-Disturbance Finite-Time Adaptive Sliding Mode Backstepping Control for PV Inverter in Master–Slave-Organized Islanded Microgrid

With the aim to solve the problem related to the power chattering and anti-disturbance performance of a photovoltaic (PV) inverter in master–slave-organized islanded microgrid, an anti-disturbance finite-time adaptive sliding mode backstepping (DFA-SMB) controller is designed in this paper. First, the topology and the second-order dynamic model of PV inverter are established based on constant DC voltage and constant reactive power control method. Subsequently, the backstepping method is adopted to perform the control of a high-order system. Moreover, a second-order sliding mode differentiator is used to realize the function of command-filter, solving the differential expansion problem caused by the derivation of virtual controller. Besides, the terminal sliding mode control (TSMC) is introduced into the q-axis controller and d-axis inner loop controller, increasing the robustness and reducing the convergence time of the system. Adaptive control and disturbance-observer (DO) are used to perform the adaptive estimation of model parameters and the observation of lumped disturbances, respectively, enhancing the dynamic characteristics of the controller. Finally, a master–slave-organized islanded microgrid with 100 kW PV array is established in MATLAB/Simulink. The results demonstrate that the proposed control method can effectively reduce power chattering and improve the anti-disturbance ability of the PV system

A Preliminary Genetic Analysis of Complement 3 Gene and Schizophrenia

<div><p>Complement pathway activation was found to occur frequently in schizophrenia, and complement 3 (C3) plays a major role in this process. Previous studies have provided evidence for the possible role of C3 in the development of schizophrenia. In this study, we hypothesized that the gene encoding C3 (C3) may confer susceptibility to schizophrenia in Han Chinese. We analyzed 7 common single nucleotide polymorphisms (SNPs) of C3 in 647 schizophrenia patients and 687 healthy controls. Peripheral <i>C3</i> mRNA expression level was measured in 23 drug-naïve patients with schizophrenia and 24 controls. Two SNPs (rs1047286 and rs2250656) that deviated from Hardy-Weinberg equilibrium were excluded for further analysis. Among the remaining 5 SNPs, there was no significant difference in allele and genotype frequencies between the patient and control groups. Logistic regression analysis showed no significant SNP-gender interaction in either dominant model or recessive model. There was no significant difference in the level of peripheral <i>C3</i> expression between the drug-naïve schizophrenia patients and healthy controls. In conclusion, the results of this study do not support <i>C3</i> as a major genetic susceptibility factor in schizophrenia. Other factors in AP may have critical roles in schizophrenia and be worthy of further investigation.</p></div

Comparison of genotype and allele frequencies of 5 <i>C3</i> SNPs in 647 schizophrenia patients and 687 healthy controls.

<p>^a<i>P</i> values were not adjusted by Bonferroni correction</p><p>^b<i>P</i> values were calculated for Hardy-Weinberg equilibrium</p><p>^c<i>P</i> values were adjusted by Bonferroni correction.</p><p>Comparison of genotype and allele frequencies of 5 <i>C3</i> SNPs in 647 schizophrenia patients and 687 healthy controls.</p

Logistic regression analysis of <i>C3</i> SNPs×gender interaction in dominant model.

<p>^a<i>P</i> values were not adjusted by Bonferroni correction</p><p>^b<i>P</i> values were adjusted by Bonferroni correction.</p><p>Logistic regression analysis of <i>C3</i> SNPs×gender interaction in dominant model.</p

Logistic regression analysis of <i>C3</i> SNPs×gender interaction in recessive model.

<p>^a<i>P</i> values were not adjusted by Bonferroni correction</p><p>NA, Not applicable.</p><p>Logistic regression analysis of <i>C3</i> SNPs×gender interaction in recessive model.</p

The Angiogenic Effect of microRNA-21 Targeting TIMP3 through the Regulation of MMP2 and MMP9

<div><p>microRNAs are a novel set of small, non-protein-coding nucleotide RNAs that negatively regulate the expression of target mRNAs. miRNA-21 is a microRNA that is highly enriched in endothelial cells. miRNA-21 has been shown to be a potential pro-angiogenic factor in some biological systems. Our previous study showed that the expression of miRNA-21 was up-regulated after spinal cord injury. However, the effect of miRNA-21 on angiogenesis in the spinal cord was unclear. In this study, to understand the role of miRNA-21 on injured endothelial cells exclusively, an oxygen and glucose deprivation model of endothelial cells was constructed, and the up-regulation of miRNA-21 was discovered in this model. An increased level of miRNA-21 by mimics promoted the survival, migration and tube formation of endothelial cells, which simultaneously inhibited tissue inhibitor of metalloproteinase-3 (TIMP3) expression and promoted matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9) expression and secretion. A decreased level of miRNA-21 by antagomir exerted an opposite effect. As is well known, survival, migration and tube formation of endothelial cells are necessary prerequisites for angiogenesis after injury. TIMP3 was validated as a direct target of miRNA-21 by dual-luciferase reporter assay. Silencing with small interfering RNA against TIMP3 promoted tube formation and increased MMP2 and MMP9 expression at the protein level. <i>In vivo</i>, we found that decreased levels of miRNA-21 inhibited angiogenesis after spinal cord injury in rats using synchrotron radiation micro-computed tomography. In summary, these findings suggest that miRNA-21 has a protective effect on angiogenesis by reducing cell death and promoting cell survival, migration and tube formation via partially targeting the TIMP3 by potentially regulating MMP2 and MMP9. TIMP3 is a functional target gene. Identifying the role of miRNA-21 in the protection of angiogenesis might offer a novel therapeutic target for secondary spinal cord injury, in which angiogenesis is indispensable.</p></div

Effect of miR-21 on HUVEC migration.

<p>(A) Scratch wound migration assay <i>in vitro</i>. After transfection with miR-21 mimics, miR-21 mimic negative control, antagomir-21 or antagomir-21 negative control, confluent HUVECs monolayers were exposed to OGD and then scratched to induce horizontal migration of HUVECs (magnification, x100). (C) Comparison of the distance of HUVECs horizontal migration at 0 h and 24 h between treatment groups and negative control groups. Values represent means±S.D; n = 3; *p<0.05. (B) Transwell chamber migration assay <i>in vitro</i>. HUVECs subjected to transfection and OGD mentioned above were trypsinized and seeded into the upper chamber and then allowed to vertically migrate for 24 h. Cells on the lower surface of the membrane were stained with 0.1% crystal violet (lavender) (magnification, x100). (D) Comparison of the rate of cell migration in the treatment groups relative to their respective negative control groups at 24 h. Values represent means±S.D; n = 3; *p<0.05, ^#p<0.05.</p

Effect of miR-21 on capillary network formation of HUVECs.

<p>(A) After transfection with miR-21 mimics, miR-21 mimic negative control, antagomir-21 or antagomir-21 negative control, HUVECs were exposed to OGD and then trypsinized and seeded onto Matrigel. Cells were incubated and allowed to form networks for 12 h, then stained with calcein-AM (Green) for 15 min. Bar = 200 μm. (B) Comparison of the number of branch nodes in the treatment groups relative to respective negative control groups at 12 h. Values represent means±S.D; n = 3; *p<0.05.</p