Regulation Of Matrix Metalloproteinases Research Articles

ID3 mediates the TGF-β1-induced suppression of matrix metalloproteinase-1 in human granulosa cells.

In the mammalian ovary, matrix metalloproteinase-1 (MMP1) is expressed in growing ovarian follicles, and MMP1-mediated extracellular matrix (ECM) remodeling plays a functional role in regulating the formation of corpus luteum. Transforming growth factor-β1 (TGF-β1) is an intraovarian growth factor that acts as a negative regulator of luteinization and progesterone production in human granulosa-lutein (hGL) cells. At present, whether TGF-β1 regulates the expression of MMP1 and thus affects ECM remodeling during corpus luteum formation remains largely unknown. The aim of this study was to investigate the effects of TGF-β1 and the molecular mechanisms by which it regulates the expression of MMP1 in immortalized human granulosa cells lines (SVOG) and primary hGL cells (obtained from consenting patients undergoing IVF treatment). We used inhibition approaches including a competitive antagonist for endogenous TGF-β type II receptor, pharmacological inhibitors (SB431542 and dorsomorphin), and specific small interfering RNA-targeted knockdown of ALK5 type I receptor and SMAD4 to demonstrate that TGF-β1 downregulates the expression and production of MMP1 via a TβRII/ALK5-mediated SMAD-dependent signaling pathway in hGL cells. Additionally, our results show that the suppressive effect of TGF-β1 on the expression of MMP1 is mediated by a transcription factor, the inhibitor of differentiation 3 (ID3) protein. Our findings provide insights into the molecular interactions and mechanisms of TGF-β1 and ID3 during the regulation of MMP1 in hGL cells.

Effects of simvastatin on matrix metalloproteinase regulation in IL-1β-induced SW1353 cells

The present study shows the basis for the anti-inflammatory effects of statins in interleukin 1β (IL-1β) induced SW1353 chondrosarcoma cell-line. The cells were pre-treated with simvastatin (5 μM, 10 μM, and 50 μM), followed by IL-1β (5 ng/mL) stimulation. Effects of simvastatin on cell viability and cytotoxicity of chondrocytes were measured with WST-1 and lactate dehydrogenase (LDH) assays, respectively. Under inflammatory conditions, in the absence/presence of simvastatin, the changes in matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase-1 (TIMP-1) expression levels were examined. Expression levels of MMP-1, -2, -3, -9, -13, and TIMP-1 and -2 were examined by qPCR. MMP-1, -9, -13, TIMP-1, and -2 levels were also determined by Western blotting. Gelatin zymography was performed to analyze the released and intracellular MMP-2 and MMP-9 activity levels. The results showed that simvastatin downregulated the degradation related genes MMP-3, MMP-13, MMP-2, MMP-9 and TIMP-2 in a dose-dependent manner.

Elevated expression of hypoxia-inducible factor-2alpha regulated catabolic factors during intervertebral disc degeneration

Headings aimsThe present study determined whether nucleus pulposus (NP) cells express hypoxia-inducible factor-2alpha (HIF-2α) and assessed its role in regulating the expression of catabolic factors during intervertebral disc degeneration. Materials and methodsHuman degenerated NP tissues were acquired to examine the HIF-2α expression levels using immunohistochemistry, western blotting, and Real-time PCR. Human NP cells were cultivated under normoxic or hypoxic conditions, and the HIF-2α expression was determined. Then, human NP cells were treated with HIF-2α plasmids, HIF-2α siRNA, and tumor necrosis factor-alpha (TNF-α) to evaluate the role of HIF-2α in regulating matrix metalloproteinase (MMP) and aggrecanase expression. An in vivo rabbit disc degeneration model was established to demonstrate that HIF-2α plays a critical role in disc degeneration. Key findingsWe found that HIF-2α had a markedly elevated expression in human degenerated discs in the Grade III stage. HIF-2α protein and gene transcript levels in vitro were relatively higher under hypoxic conditions. The expression of MMP-13, ADAMTS-4 was decreased significantly in HIF-2α silencing condition, while the over-expression resulted in significantly increased levels of MMP-13 and ADAMTS-4. When cytokine TNF-α was added, HIF-2α was induced by nuclear factor-κB (NF-κB). The in vivo experiments showed that the HIF-2α controlled the catabolic factors MMP-13 and ADAMTS-4 that regulated the collagen II and aggrecan metabolism in disc degeneration. SignificanceHIF-2α is a catabolic regulator in disc degeneration and directly controls the catabolic genes. The suppression of HIF-2α expression leads to decelerates extracellular matrix degradation that might represent a therapeutic target for the degenerative disc.

Genetic reduction of MMP-9 in the Fmr1 KO mouse partially rescues prepulse inhibition of acoustic startle response

Sensory processing abnormalities are consistently associated with autism, but the underlying mechanisms and treatment options are unclear. Fragile X Syndrome (FXS) is the leading known genetic cause of intellectual disabilities and autism. One debilitating symptom of FXS is hypersensitivity to sensory stimuli. Sensory hypersensitivity is seen in both humans with FXS and FXS mouse model, the Fmr1 knock out (Fmr1 KO) mouse. Abnormal sensorimotor gating may play a role in the hypersensitivity to sensory stimuli. Humans with FXS and Fmr1 KO mice show abnormalities in acoustic startle response (ASR) and prepulse inhibition (PPI) of startle, responses commonly used to quantify sensorimotor gating. Recent studies have suggested high levels of matrix metalloproteinase-9 (MMP-9) as a potential mechanism of sensory abnormalities in FXS. Here we tested the hypothesis that genetic reduction of MMP-9 in Fmr1 KO mice rescues ASR and PPI phenotypes in adult Fmr1 KO mice. We measured MMP-9 levels in the inferior colliculus (IC), an integral region of the PPI circuit, of WT and Fmr1 KO mice at P7, P12, P18, and P40. MMP-9 levels were higher in the IC of Fmr1 KO mice during early development (P7, P12), but not in adults. We compared ASR and PPI responses in young (P23-25) and adult (P50-80) Fmr1 KO mice to their age-matched wildtype (WT) controls. We found that both ASR and PPI were reduced in the young Fmr1 KO mice compared to age-matched WT mice. There was no genotype difference for ASR in the adult mice, but PPI was significantly reduced in the adult Fmr1 KO mice. The adult mouse data are similar to those observed in humans with FXS. Genetic reduction of MMP-9 in the Fmr1 KO mice resulted in a rescue of adult PPI responses to WT levels. Taken together, these results show sensorimotor gating abnormalities in Fmr1 KO mice, and suggest the potential for MMP-9 regulation as a therapeutic target to reduce sensory hypersensitivity.

CNBP controls tumor cell biology by regulating tumor-promoting gene expression.

Cellular nucleic acid-binding protein (CNBP) is associated with cell proliferation, and its expression is elevated in human tumors, but the molecular mechanisms of CNBP in tumor cell biology have not been fully elucidated. In this study, we report that CNBP is a transcription factor essential for regulating matrix metalloproteinases mmp-2, mmp-14, and transcription factor e2f2 gene expression by binding to their promoter regions via a sequence-specific manner. Importantly, epidermal growth factorstimulation is required to induce CNBP phosphorylation and nuclear transport, thereby promoting the expression of mmp-2, mmp-14, and e2f2 genes. As a consequence, loss of cnbp attenuates the ability of tumor cell growth, invasion, and migration. Conversely, overexpression of cnbp is associated with tumor cell biology. Collectively, our findings reveal CNBP as a key transcriptional regulator of tumor-promoting target genes to control tumor cell biology.

Low-dose doxycycline inhibits hydrogen peroxide-induced oxidative stress, MMP-2 up-regulation and contractile dysfunction in human saphenous vein grafts.

Background: Cardiopulmonary bypass (CPB) applied during coronary artery bypass grafting (CABG), promotes inflammation, generation of reactive oxygen species (ROS) and up-regulation of matrix metalloproteinases (MMPs). All these complications may lead to contractile dysfunction, restenosis and early graft failure, restricting long-term efficacy of bypass grafts. Low-dose doxycycline is a potent MMP inhibitor and ROS scavenger. In this study, we aimed to investigate the effects of doxycycline on ROS generation, MMP regulation and contractile dysfunction induced by H2O2 in human saphenous vein (HSV) grafts.Methods: HSV grafts (n=7) were divided into four groups after removing endothelial layer by mechanical scratching and incubated with 10 µM H2O2 and/or 10 µM doxycycline for 16 hrs. Untreated segments served as control. Concentration–response curves to noradrenaline (NA), potassium chloride (KCl), serotonin (5-HT) and papaverine were performed. Superoxide anion and other ROS levels were determined by using lucigenin- and luminol-enhanced chemiluminescence assays, respectively. Expression/activity of gelatinases (MMP-2/MMP-9) was examined by gelatin zymography. MMP-13 expression was evaluated by immunostaining/immunoscoring.Results: H2O2 incubation increased superoxide anion and other ROS levels. Doxycycline prevented these increments. H2O2 suppressed contractile responses to NA, KCl and 5-HT. Doxycycline ameliorated contractions to NA and KCl but not to 5-HT. H2O2 or doxycycline did not altered relaxation to papaverine. MMP-2 and MMP-13 expression increased with H2O2, but doxycycline inhibited MMP-2 up-regulation/activation.Conclusion: Low-dose doxycycline may have beneficial effects on increased oxidative stress, MMP up-regulation/activation and contractile dysfunction in HSV grafts.

Immunohistochemical expression and localization of MMP-9, MMP-13, E-Cadherin and Ki-67 in road pavers' skin chronically exposed to bitumen products.

To investigate the matrix metalloproteinase (MMP)-9, (MMP)-13, E-Cadherin and Ki-67 expressions in road pavers' skin chronically exposed to bitumen products in order to contribute to a better understanding of the earlier tissue alteration. Skin punch biopsies from 16 daily exposed workers and a control group were studied by immunohistochemistry. Morphometric and densitometric analyses were also conducted. Morphological specimen evaluation of skin of road pavers showed epidermal thinning, flattening and loss of intercellular junction with a decreased expression of E-cadherin confined to the basal skin layer, together with MMP-9 and MMP-13 overexpressions in all epidermis layers, vascular structures and adnexa. No immunohistochemical alteration was reported for Ki-67 vs normal skin. Results from this study show that overexpression of MMP-9 and MMP-13 may represent an early response of the first human barrier to exposure to bitumen products. Regulation of MMPs could be one of the strategies to prevent primary skin disease.

Inhibitory Effect of Total Ginsenoside on Pulmonary Fibrosis Induced by Bleomycin is involved in Matrix Metalloproteinase

Pulmonary fibrosis is a refractory disease of the respiratory system. As the active components of Panax ginseng, total ginsenoside (TG) have been reported to have antioxidant, anti‐inflammatory and immune modulatory activity. We previously showed that TG has protective effect on pulmonary fibrosis. The purpose of the study was to investigate whether the mechanism of TG against pulmonary fibrosis is involved in the regulation of matrix metalloproteinase (MMPs). The pulmonary fibrosis model of BALB/c mice was replicated by injecting BLM into the trachea. TG (40, 80, 160 mg/kg/day) were given for 28 consecutive days after surgery. Pulmonary fibrosis was determined by measuring lung coefficient, Haematoxylin and Eosin (HE) staining, Masson's trichrome staining, and expression of the alpha smooth muscle actin (α‐SMA, a gene related to pulmonary fibrosis) in lung tissues. Real‐time quantitative PCR and western blot were used to detect matrix metalloproteinase‐2 (MMP‐2), matrixmetalloproteinase‐9 (MMP‐9) and tissue inhibitor of metalloproteinase‐1 (TIMP‐1) mRNA and protein levels respectively. In the present study, TG (40, 80, and 160 mg/kg/d) treatment could evidently ameliorate pulmonary fibrosis and down‐regulate the expression of MMP‐2, MMP‐9 and TIMP‐1 mRNA and protein levels in BLM‐treated mice. The protective effect of TG on bleomycin induced pulmonary fibrosis in mice is related to the regulation of matrix metalloproteinases.Support or Funding InformationThis research was supported by the Social Program for Tackling Key Problems of National Natural Science Foundation of China (NO.81360660 and 81860732.)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Structural Elucidation of Engineered Tissue Inhibitor of Metalloproteinases‐1 (TIMP‐1) Variants with Improved Binding Affinity toward Matrix Metalloproteinase‐3 (MMP‐3)

Tissue inhibitors of metalloproteinases (TIMPs) are natural inhibitors of matrix metalloproteinases (MMPs), enzymes known for contributions to diseases including cancer and fibrosis. The TIMP N‐terminal domain, regarded as the “inhibitory domain”, has been the center of attention both for understanding natural regulation of MMPs by TIMPs, and for developing protein‐based MMP inhibitors for therapeutic applications. The role of the TIMP C‐terminal domain in MMP inhibition has not been well studied. I have used directed evolution via yeast surface display for protein engineering of full‐length human TIMP‐1 toward development of MMP‐3‐targeted ultra‐binders. TIMP‐1 variants with up to 10‐fold improvement in MMP‐3 binding (compared to WT‐TIMP‐1) were isolated after six rounds of library screening using fluorescence‐activated cell sorting (FACS). Analysis of individual and paired mutations from the selected TIMP‐1 variants revealed a cooperative effect between distant mutations on the N‐ and C‐terminal TIMP domains, positioned on opposite sides of the interaction interface with MMP‐3. I have co‐crystallized two TIMP‐1 variants containing single and composite mutations in complex with the catalytic domain of MMP‐3 and solved the X‐ray crystal structures of these complexes. The protein structures reveal substantial conformational changes in the TIMP‐1 binding interfaces near the two cooperative mutations. Affinity appears to be strengthened by tighter cinching of a reciprocal tyrosine clasp formed between the N‐terminal loop of TIMP‐1 and the proximal MMP3 interface, and adoption of an alpha‐helical conformation by a segment of the TIMP‐1 C‐terminal domain, resulting in stabilized interactions between the two TIMP‐1 domains and improved hydrophobic interactions between TIMP‐1 and MMP‐3. Our protein engineering and structural studies provide novel insight into the cooperative function of N‐ and C‐terminal TIMP domains and the significance of peripheral TIMP epitopes in MMP recognition. Our results further point to new approaches for design of TIMP‐based protein therapeutics with improved affinity and selectivity.Support or Funding InformationThis work was supported by grants DOD W81XWH‐16‐2‐0030, and NIH R21 CA205471. Diffraction data were measured at the Berkeley National Synchrotron Light Source.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Overexpression of EPAC2 reduces the invasion of glioma cells via MMP-2.

Exchange proteins directly activated by cAMP (EPACs) are crucial cyclic adenosine 3′,5′-monophosphate- determined signaling pathway intercessors, which are associated with the pathogenesis of neurological disorders and numerous human diseases. To the best of our knowledge, the role of EPAC2 signaling via matrix metalloproteinase 2 (MMP-2) in the pathogenesis of glioma has not been studied. Therefore, the present study focused on the role of EPAC2 in glioma, and assessed the invasiveness of human glioma cell lines following EPAC2 overexpression. Expression levels of EPAC2 in normal brain tissues and clinical glioma specimens were detected by western blotting. An EPAC2 overexpression vector was transfected into U251 and U87 cell lines to increase the expression levels of EPAC2. Expression levels of MMP-2 were detected by western blotting, and the invasive abilities of glioma cells were detected by a Transwell assay. EPAC2 was relatively highly expressed in normal brain tissue, while EPAC2 expression was significantly decreased in clinical glioma specimens (P<0.01). In vitro transfection of EPAC2 overexpression vector significantly reduced the MMP-2 protein levels of glioma cells, and, at the same time, the invasive cell number was significantly decreased in a Transwell assay. The present study demonstrated that MMP-2 regulation via EPAC2 overexpression is a novel promising therapeutic route in malignant types of glioma.

DDR2–CYR61–MMP1 Signaling Pathway Promotes Bone Erosion in Rheumatoid Arthritis Through Regulating Migration and Invasion of Fibroblast-Like Synoviocytes

Regulation of matrix metalloproteinases (MMPs) by collagen in the fibroblast-like synoviocytes (FLSs) plays a critical role in joint destruction in rheumatoid arthritis (RA). Our previous study indicated that discoidin receptor 2 (DDR2) mediated collagen upregulation of MMPs. However, the precise underlying mechanism remains unclear. We report here that CYR61, a secreted, extracellular matrix-associated signaling protein which is capable of regulating a broad range of cellular activities, including cell adhesion, migration, proliferation, and apoptosis, is significantly upregulated in collagen II-stimulated RA FLS. Further studies found that collagen II-activated phosphorylated-DDR2 induces CYR61 through activation of transcription factor activator protein 1 (AP-1). The elevated CYR61, in turn, accelerates MMP1 production via ETS1 (ETS proto-oncogene 1). In addition, CYR61 significantly promotes FLS invasion and migration. Blockade of CYR61 by an adenovirus expressing CYR61 shRNA (Ad-shCYR61) in vivo remarkably ameliorated the severity of arthritis, reduced inflammatory cytokine secretion, and attenuated bone erosion as detected by micro-computed tomography (μCT), in collagen-induced arthritis (CIA) rats. Taken together, we uncovered the Collagen II-DDR2-AP-1-CYR61-ETS1-MMP1 loop in RA FLS. In which, CYR61 acts as a hinge to promote cartilage damage through regulating FLS invasion, migration, and MMP1 production and the inflammatory cascade in RA. Thus, CYR61 may be a promising diagnostic and therapeutic target for RA treatment. © 2016 American Society for Bone and Mineral Research.

Silencing Y-box binding protein-1 inhibits triple-negative breast cancer cell invasiveness via regulation of MMP1 and beta-catenin expression.

Y-box binding protein-1 (YB-1), an important transcription and translation regulator protein, is known to increase cancer cell invasiveness and spreading. Here, we report its role in breast cancer, particularly in mediating cell invasion in triple-negative breast cancer (TNBC). YB-1 stable knockdown (shYB-1) significantly reduced the invasive potential of MDA-MB-231 TNBC cells in 2D and 3D (spheroid) cultures. Whole proteome mass spectrometry analysis showed an enrichment of cell adhesion and cell to matrix interaction proteins, notably, matrix metalloproteinase-1 (MMP1) and beta-catenin (CTNNB1), which are known to play critical roles in cancer metastasis. shYB-1 cells exhibited substantial downregulation of MMP1 and CTNNB1 mRNA and protein expression, with reduced MMP1 enzyme activity. YB-1 was also observed to bind to the promoter of MMP1 and overexpression of MMP1 plasmid in shYB-1 cells increased cell invasion. Finally, analysis of tumour samples from the Gene Expression-Based Outcome for Breast Cancer Online (GOBO) database revealed that high gene expressions of YBX1, MMP1 and CTNNB1 predict for a significantly lower 10-year distant metastasis free survival. Altogether, this study shows that YB-1 mediates breast cancer invasion and metastasis via regulation of MMP1 and beta-catenin.

Low-intensity exercise in the prevention of cardiac insulin resistance-related inflammation and disturbances in NOS and MMP-9 regulation in fructose-fed ovariectomized rats.

Exercise is important nonpharmacological treatment for improvement of insulin sensitivity in menopause. However, its effect on menopausal cardiac insulin resistance is needing further research. We investigated protective effects of low-intensity exercise on cardiac insulin signaling, inflammation, regulation of nitric oxide synthase (NOS) and matrix metalloproteinase 9 (MMP-9) in ovariectomized (OVX) Wistar rats, submitted to 10% fructose solution for 9 weeks. OVX rats were divided into control, sedentary fructose, and exercise fructose groups. Measurements of physical and biochemical characteristics were carried out to evaluate metabolic syndrome development. Messenger RNA and protein levels and phosphorylation of cardiac insulin signaling molecules, endothelial and inducible NOS (eNOS and iNOS), p65 subunit of nuclear factor κB (NFκB), tumor necrosis factor α (TNF-α), suppressor of cytokine signaling 3 (SOCS3), and MMP-9 were analyzed. Fructose increased insulin level, homeostasis model assessment (HOMA) index, and visceral adipose tissue weight, while low-intensity exercise prevented insulin level and HOMA index increase. Fructose also decreased cardiac pAkt (Ser473), peNOS (Ser1177) and increased insulin receptor substrate 1 (IRS1) phosphorylation at Ser307, pNFκB (Ser276) and NFκB and MMP-9 content, without any effect on iNOS, protein-tyrosine phosphatase 1B, TNF-α, and SOCS3. Exercise prevented changes in pIRS1 (Ser307), pAkt (Ser473), peNOS (Ser1177), pNFκB (Ser276), and NFκB expression. In addition, exercise increased pIRS1 (Tyr632), pAkt (Thr308), and eNOS expression. Low-intensity exercise prevented cardiac insulin signaling disarrangement in fructose-fed OVX rats and therefore eNOS dysfunction, as well as pro-inflammatory signaling activation, without effect on tissue remodeling, suggesting physical training as a way to reduce cardiovascular risk.

Valvular interstitial cells down regulate matrix metalloproteinase 9 activity and expression in human monocyte-derived macrophages: Potential impact on aortic valve stenosis pathophysiology

Aortic valve stenosis (AVS) involves inflammation, excess deposition of collagen-rich extracellular matrix (ECM) and calcification. Recent studies have shown that M1 macrophages observed in stenosed valve promote calcification of valvular interstitial cells (VIC), the most prevalent cell type in aortic valve.

Green tea-induced epigenetic reactivation of tissue inhibitor of matrix metalloproteinase-3 suppresses prostate cancer progression through histone-modifying enzymes.

Green tea polyphenols (GTPs) and their major constituent, epigallocatechin-3-gallate (EGCG), have been reported to demonstrate many interesting biological activities, including anticancer properties. Recent studies on prostate cancer provide strong evidence that epigenetic mechanisms are major players in the regulation of matrix metalloproteinases (MMPs) and their binding partner tissue inhibitor of MMPs (TIMPs) involved in prostate cancer progression. Here we demonstrate that GTP/EGCG mediate epigenetic reactivation of TIMP-3 that plays a key role in suppressing invasiveness and cancer progression. Treatment of human prostate cancer DUPRO and LNCaP cells with 10 µg/mL GTP and 20 µM EGCG induced TIMP-3 mRNA and protein expression. This transcriptional activation of TIMP-3 was associated with the decrease in the expression of both enhancers of zeste homolog 2 (EZH2) and its catalytic product trimethylation of histone H3 at lysine 27 (H3K27me3) repressive marks at the TIMP-3 promoter with an accompanying increase in histone H3K9/18 acetylation. In addition, GTP/EGCG treatment significantly reduced class I histone deacetylase (HDAC) activity/expression and EZH2 and H3K27me3 levels in prostate cancer cells. EGCG/GTP exposure also reduced MMP-2/MMP-9 gelatinolytic activity and abrogated invasion and migration capabilities in these cells. Silencing of EZH2 and class I HDACs strikingly increased the expression of TIMP-3 independent of DNA methylation. Furthermore, clinical trials performed on patients undergoing prostatectomy consuming 800 mg EGCG (Polyphenon E) up to 6 weeks and grade-matched controls demonstrate an increase in plasma TIMP-3 levels. A marked reduction in class I HDACs activity/expression and EZH2 and H3K27me3 levels were noted in GTP-supplemented prostate tissue. Our findings highlight that TIMP-3 induction, as a key epigenetic event modulated by green tea in restoring the MMP:TIMP balance suppresses prostate cancer progression.

IL-36γ regulates mediators of tissue homeostasis in epithelial cells

IL-36 cytokines are critical regulators of mucosal inflammation and homeostasis. IL-36γ regulates the expression of inflammatory cytokines and antimicrobial proteins by gingival epithelial cells (e.g. TIGK cells). Here, we show that IL-36γ also regulates the expression of matrix metalloproteinase 9 (MMP9) and neutrophil gelatinase-associated lipocalin (NGAL), important mediators of antimicrobial immunity and tissue homeostasis in mucosal epithelia. MMP9 and NGAL were not similarly induced by IL-17 or IL-22, thus indicating the importance of IL-36γ in the regulation of MMP9 and NGAL. Mechanistically, MMP9 and NGAL expression was demonstrated to be induced in an IRAK1- and NF-κB-dependent manner. Furthermore, signaling by p38 MAP kinase may enable their expression to be independently regulated by IL-36γ. The stronger IL-36γ-inducible expression of MMP9 and NGAL in terminally differentiating TIGK cells suggests that control of their expression is associated with the maturation of the gingival epithelium. Although MMP9 and NGAL expression in epithelial cells can also be induced by bacteria, their expression in TIGK cells was not induced by the periodontal pathogen Porphyromonas gingivalis, most likely due to antagonism by the gingipain proteinase virulence factors. This study advances our understanding of how IL-36γ may promote oral mucosal immunity and tissue homeostasis, and how this may be dysregulated by bacterial pathogens.

A unique role of thyroid hormone receptor β in regulating notochord resorption during Xenopus metamorphosis

Tail resorption during anuran metamorphosis is perhaps the most dramatic tissue transformation that occurs during vertebrate development. Earlier studies in highly related anuran species Xenopus laevis and Xenopus tropicalis have shown that thyroid hormone (T3) receptor (TR) plays a necessary and sufficient role to mediate the causative effect of T3 on metamorphosis. Of the two known TR genes in vertebrates, TRα is highly expressed during both premetamorphosis and metamorphosis while TRβ expression is low in premetamorphic tadpoles but highly upregulated as a direct target gene of T3 during metamorphosis, suggesting potentially different functions during metamorphosis. Indeed, gene knockout studies have shown that knocking out TRα and TRβ has different effects on tadpole development. In particularly, homozygous TRβ knockout tadpoles become tailed frogs well after sibling wild type ones complete metamorphosis. Most noticeably, in TRβ-knockout tadpoles, an apparently normal notochord is present when the notochord in wild-type and TRα-knockout tadpoles disappears. Here, we have investigated how tail notochord resorption is regulated by TR. We show that TRβ is selectively very highly expressed in the notochord compared to TRα. We have also discovered differential regulation of several matrix metalloproteinases (MMPs), which are known to be upregulated by T3 and implicated to play a role in tissue resorption by degrading the extracellular matrix (ECM). In particular, MMP9-TH and MMP13 are extremely highly expressed in the notochord compared to the rest of the tail. In situ hybridization analyses show that these MMPs are expressed in the outer sheath cells and/or the connective tissue sheath surrounding the notochord. Our findings suggest that high levels of TRβ expression in the notochord specifically upregulate these MMPs, which in turn degrades the ECM, leading to the collapse of the notochord and its subsequent resorption during metamorphosis.

MiRNA-155 expression and role in pathogenesis in spinal tuberculosis-induced intervertebral disc destruction.

The current study aimed to investigate microRNA-155 (miR-155) expression in spinal tuberculosis-induced intervertebral disc destruction and its regulatory role in disease pathogenesis. A total of 26 patients with intervertebral disc destruction induced by spinal tuberculosis and 31 healthy individuals were included. Reverse transcription-quantitative polymerase chain reactions, western blot analysis and ELISA were performed to detect mRNA and protein expression levels. A bioinformatics analysis was applied to predict the upstream regulator of matrix metalloproteinase (MMP)13, which was confirmed by dual-luciferase reporter assay. Compared with the control group, mRNA and protein expression levels of MMP13 were significantly increased in the intervertebral disc of patients with spinal tuberculosis. However, miR-155 expression in the intervertebral disc of patients with spinal tuberculosis was significantly decreased compared with the control group. Dual-luciferase reporter assays suggested that miR-155 bound to the 3′-untranslated region of MMP13 to regulate gene expression. In primary annulus fibrosus cells, upregulated miR-155 expression significantly decreased MMP13 expression in the cells and culture supernatant, whereas it increased type II collagen expression. Upregulated MMP13 expression in the intervertebral disc in patients with spinal tuberculosis may be correlated with downregulated miR-155 expression. miR-155 may regulate expression levels of associated proteins in the intervertebral disc via modulating MMP13 expression, which contributes to the disease pathogenesis. The results of the current study may provide the theoretical basis for the diagnosis and treatment of disc damages caused by spinal tuberculosis.

Potential Therapeutic Features of Human Amniotic Mesenchymal Stem Cells in Multiple Sclerosis: Immunomodulation, Inflammation Suppression, Angiogenesis Promotion, Oxidative Stress Inhibition, Neurogenesis Induction, MMPs Regulation, and Remyelination Stimulation.

Multiple sclerosis (MS) is an inflammatory and degenerative disorder of the central nervous system with unknown etiology. It is accompanied by demyelination of the nerves during immunological processes in the presence of oxidative stress, hypoxia, cerebral hypo-perfusion, and dysregulation in matrix metalloproteinases (MMPs). Human amniotic mesenchymal stem cells (hAMSCs) as pluripotent stem cells possess some conspicuous features which could be of therapeutic value in MS therapy. hAMSCs could mimic the cascade of signals and secrete factors needed for promoting formation of stable neovasculature and angiogenesis. hAMSCs also have immunomodulatory and immunosuppressive effects on inflammatory processes and reduce the activity of inflammatory cells, migration of microglia and inhibit recruitment of certain immune cells to injury sites. hAMSCs attenuate the oxidative stress supported by the increased level of antioxidant enzymes and the decreased level of lipid peroxidation products. Furthermore, hAMSCs enhance neuroprotection and neurogenesis in brain injuries by inhibition of inflammation and promotion of neurogenesis. hAMSCs could significantly increase the expression of neurotrophic factors, which prevents neurons from initiating programmed cell death and improves survival, development, and function of neurons. In addition, they induce differentiation of neural progenitor cells to neurons. hAMSCs could also inhibit MMPs dysregulation and consequently promote the survival of endothelial cells, angiogenesis and the stabilization of vascular networks. Considering the mentioned evidences, we hypothesized here that hAMSCs and their conditioned medium could be of therapeutic value in MS therapy due to their unique properties, including immunomodulation and inflammation suppression; angiogenesis promotion; oxidative stress inhibition; neurogenesis induction and neuroprotection; matrix metalloproteinases regulation; and remyelination stimulation.

MiRNA-218 regulates osteoclast differentiation and inflammation response in periodontitis rats through Mmp9.

Periodontitis is a multiple infection and inflammatory disease featured by connective tissue homeostasis loss, periodontal inflammation, and alveolar bone resorption. MicroRNAs (miRNAs) are involved in the mediation of a large scale of pathological processes. Here, we show that miRNA-218 provides protective effect on periodontitis via regulation of matrix metalloproteinase-9 (Mmp9). This pathway is aberrant in periodontium from rats with periodontitis and human periodontal ligament progenitor cells stimulated by lipopolysaccharide, with downregulation of miR-218 and higher levels of Mmp9 compared with periodontium from healthy rats and cells without stimulation. Overexpression of miR-218 can suppress the degradation of Collagen Types I and IV and dentin sialoprotein (DSP), attenuate osteoclast formation, and inhibit the secretion of proinflammatory cytokines. On the other hand, overexpression of Mmp9 promotes the degradation of Collagen Types I and IV and DSP as well as RANKL-induced osteoclast formation and elevates inflammatory factors levels. Furthermore, the inhibitory effect of miR-218 was prevented by rescuing the Mmp9 expression. In addition, we also have showed that miR-218 was able to attenuate bone resorption and inflammation in a periodontitis rat model. Collectively, our findings therefore suggest that miR-218 acts as a protective role in periodontitis through the regulation of Mmp9.