ADAM10 Expression Research Articles

Circular RNA circNINL promotes breast cancer progression through activating β-catenin signaling via miR-921/ADAM9 axis.

We investigated the expression and functions of circular RNA (circRNA) circNINL and miR-921 in breast cancer (BC) in this study. We found that the expression of circNINL increased while the expression of miR-921 decreased in BC tissues and cell lines, and their anomalous expressions were associated with malignant features and poor prognostic of BC. Then, we demonstrated that circNINL could interact with miR-921 and facilitate BC cells malignant process including proliferation acceleration, migration enhancement and apoptosis evasion via sponging miR-921 in vitro. Further investigations revealed that circNINL/miR-921 axis could mediate the expression of ADAM9 which was a direct target of miR-921. In addition, we exhibited that ADAM9 may activate β-catenin signaling by interacting with E-cadherin. We presented the vital roles of circNINL/miR-921/ADAM9/β-catenin signaling in the progression of BC.

CX3CR1 Depletion Promotes the Formation of Platelet-Neutrophil Complexes and Aggravates Acute Peritonitis.

Peritonitis is a life-threatening condition on intensive care units. Inflammatory cytokines and their receptors drive inflammation, cause the formation of platelet-neutrophil complexes (PNCs) and therefore the migration of polymorphonuclear neutrophils (PMNs) into the inflamed tissue. CX3CL1 and its receptor CX3CR1 are expressed in various cells, and promote inflammation. The shedding of CX3CL1 is mediated by a disintegrin and metalloprotease (ADAM) 17. The role of the CX3CL1-CX3CR1 axis in acute peritonitis remains elusive. In zymosan-induced peritonitis, we determined the formation of PNCs in the blood and the expression of PNC-related molecules on PNCs. PMN migration into the peritoneal lavage was evaluated in wild-type (WT) and CX3CR1-/- animals by flow cytometry. CX3CL1, ADAM17, and the expression of various inflammatory cytokines were detected. Further, we determined the inflammation-associated activation of the intracellular transcription factor extracellular signal-regulated kinase 1/2 (ERK1/2) by Western blot. The PMN accumulation in the peritoneal lavage and the PNC formation in the circulation were significantly raised in CX3CR1-/- compared with WT animals. The expression of PNC-related selectins on PNCs was significantly increased in the blood of CX3CR1-/- animals, as well as cytokine levels. Further, we observed an increased activation of ERK1/2 and elevated ADAM17 expression in CX3CR1-/- during acute inflammation. Selective ERK1/2 inhibition ameliorated inflammation-related increased ADAM17 expression. A CX3CR1 deficiency raised the release of inflammatory cytokines and increased the PNC formation respectively PMN migration via an elevated ERK1/2 activation during acute peritonitis. Further, we observed a link between the ERK1/2 activation and an elevated ADAM17 expression on PNC-related platelets and PMNs during inflammation. Our data thus illustrate a crucial role of CX3CR1 on the formation of PNCs and regulating inflammation in acute peritonitis.

Autophagy-Dependent Increased ADAM10 Mature Protein Induced by TFEB Overexpression Is Mediated Through PPARα.

Nonamyloidogenic processing of amyloid precursor protein (APP) by augmenting ADAM10 is a promising therapeutic strategy for Alzheimer's disease (AD). Therefore identification of molecular pathways that regulate ADAM10 expression is crucial. Autophagy is strongly dysregulated in AD, and TFEB was recently shown to be a master regulator of autophagy-lysosome pathway (ALP). Here, we report that TFEB expression in HeLa cells increased ADAM10 mature form by 72% (p < 0.01, n = 4), while TFEB knockdown by CRISPR strategy reduced ADAM10 mature form by 36% (p < 0.05, n = 4). Autophagy inhibition by 3-methyladenine (3-MA), but not bafilomycin A1 (BAF1), reduced ADAM10 mature form by 49% (p < 0.05, n = 4) in the TFEB expressing HeLa cells. Autophagy activation by 3h of starvation increased ADAM10 to 91% (p < 0.001, n = 6) relative to 51% (p < 0.01, n = 6) in the nutrient-fed cells. Further, siRNAs targeted against PPARα in HeLa cells decreased ADAM10 levels by 28% (p < 0.05, n = 6) relative to the cells treated with scrambled siRNAs. Further, incubation of EGFP-TFEB expressing HeLa cells with PPARα antagonist, but not PPARβ or PPARγ antagonists, prevented TFEB-induced increase in ADAM10 levels. Importantly, flag-TFEB expression in the brain also increased ADAM10 by 60% (p < 0.05, n = 3) in the cortical and 34% (p < 0.001, n = 3) in the hippocampal homogenates. ADAM10 activity also increased by 57% (p < 0.01, n = 3) in the HeLa cells. Finally, TFEB-induced ADAM10 potentiation led to increased secretion of sAPPα by 154% (p < 0.001, n = 3) in the cortex and 62% (p < 0.001, n = 3) in the hippocampus. Thus, TFEB expression enhances nonamyloidogenic processing of APP. In conclusion, TFEB expression induces ADAM10 in an autophagy-dependent manner through PPARα.

Increased ADAM12 Expression Predicts Poor Prognosis in Cervical Cancer Patients before General Anesthesia.

The current study aims to investigate the expression and diagnostic value of ADAM12 in patients with cervical cancer before general anesthesia. Seventy-eight cases of cervical cancer patients were included in the present study. RT-PCR and western blot were used to detect the expression of ADAM12 in cervical cancer tissues and adjacent tissues. Meanwhile, the expression of secretory ADAM12 in serum of cervical cancer patients and healthy people was detected by ELISA. The relationship between ADAM12 expression and prognosis of cervical cancer patients was analyzed. ROC analysis was carried out to explore the diagnostic value of ADAM12. Our data showed that the expression of ADAM12 mRNA and protein in cervical cancer tissues was significantly up-regulated compared with the adjacent tissues. ELISA assay showed that the content of ADAM12 in serum of cervical cancer patients was significantly higher than that of healthy people. Furthermore, ADAM12 expression was closely related to tumor invasion, TNM stage, lymph node metastasis and tumor differentiation. Kaplan-Meier survival analysis showed that the overall survival rate of patients with high ADAM12 was significantly lower than that of patients with low ADAM12 expression. The AUC of ADAM12, CEA, CA125, and SCC for cervical cancer was 0.893, 0.510, 0.769 and 0.550, respectively, while the highest value of AUC was 0.946 by the combination of the four indexes. In summary, increased expression of ADAM12 in cervical cancer patients can be used as an independent prognostic marker.

ADAM10 expression in gastric adenocarcinoma: Results of a curative gastrectomy cohort.

Objective:Gastric cancer is among the most common human cancers with high mortality rates. ADAM10, a member of the ADAM (a disintegrin and metalloproteinase) family has also been found to be associated with gastric carcinoma and has been suggested as a potential therapeutic target. Here, we investigated the association of ADAM10 expression with prognosis in gastric adenocarcinoma patients that underwent gastric resection with D2 lymph node dissection.Methods:Total 86 consecutive patients that underwent resection for gastric adenocarcinoma were included. Immunohistochemical ADAM10 expression and its association with clinicopathological parameters were analyzed. Univariate and multivariate analyses and survival analyses were performed using SPSS ver.22.Results:High grade tumors, advanced stage tumors and diffuse type tumors showed significantly worse prognosis. A statistically significant association between ADAM10 expression and overall survival (OS) was observed in the univariate analysis, however, this association did not maintain its significance in the multivariate analysis. No statistically significant association was found ADAM-10 expression and clinicopathological parameters.Conclusion:Immunohistochemical ADAM10 expression may be used as a prognostic marker in gastric adenocarcinoma, however, introduction of a standardized immunohistochemical scoring system seems to be necessary for evaluation of ADAM10 staining.

Overexpression of ADAM9 decreases radiosensitivity of hepatocellular carcinoma cell by activating autophagy

ABSTRACT A disintegrin and a metalloprotease (ADAM)9 upregulated within human hepatocellular carcinoma (HCC) cells, but its effect on HCC radiosensitivity remains unknown. The present work aimed to examine the effect of ADAM9 on HCC radiosensitivity and to reveal its possible mechanism, which may be helpful in identifying a potential therapeutic strategy. Changes in ADAM9 expression after X-ray irradiation were identified using western blot, qRT-PCR, and immunofluorescence. ADAM9 stable knockdown and overexpression cell lines were constructed using lentivirus packaging. The radiosensitivity of HCC cells with altered ADAM9 expression was examined by CCK-8 assays, subcutaneous tumorigenesis experiments, and clone formation assays. This study also determined how autophagy affected HCC cell radiosensitivity. Furthermore, ADAM9, p62 and Bax expressions in HCC tissues that were removed after radiotherapy were detected by immunohistochemistry, and the relationship among the levels of these molecules was statistically analyzed. The level of ADAM9expression in HCC cells increased after X-ray irradiation. Through CCK-8 assays, subcutaneous tumorigenesis experiments, and clone formation assays, this work discovered the increased MHCC97H cell radiosensitivity after ADAM9 knockdown, and the radiosensitivity of Huh7 cells decreased after the overexpression of ADAM9. Furthermore, ADAM9 induced HCC cell autophagy via downregulating Nrf2 expression, while autophagy inhibition or induction reversed the effects of altered ADAM9 expression on radiosensitivity. Moreover, ADAM9 level showed a negative correlation with Bax and p62 expression within HCC tissues after radiotherapy. Taken together, ADAM9 decreased the radiosensitivity of HCC cells, and autophagy mediated this process.

Effect of ADAM10 Gene Polymorphisms and Expression on Hepatocellular Carcinoma

Effect of ADAM10 Gene Polymorphisms and Expression on Hepatocellular Carcinoma

ADAM9 functions as a transcriptional regulator to drive angiogenesis in esophageal squamous cell carcinoma.

Hypoxia and angiogenesis play key roles in the pathogenesis of esophageal squamous cell carcinoma (ESCC), but regulators linking these two pathways to drive tumor progression remain elusive. Here we provide evidence of ADAM9's novel function in ESCC progression. Increasing expression of ADAM9 was correlated with poor clinical outcomes in ESCC patients. Suppression of ADAM9 function diminished ESCC cell migration and in vivo metastasis in ESCC xenograft mouse models. Using cellular fractionation and imaging, we found a fraction of ADAM9 was present in the nucleus and was uniquely associated with gene loci known to be linked to the angiogenesis pathway demonstrated by genome-wide ChIP-seq. Mechanistically, nuclear ADAM9, triggered by hypoxia-induced translocation, functions as a transcriptional repressor by binding to promoters of genes involved in the negative regulation of angiogenesis, and thereby promotes tumor angiogenesis in plasminogen/plasmin pathway. Moreover, ADAM9 suppresses plasminogen activator inhibitor-1 gene transcription by interacting with its transcription factors at the promoter. Our findings uncover a novel regulatory mechanism of ADAM9 as a transcriptional regulator in angiogenesis and highlight ADAM9 as a promising therapeutic target for ESCC treatment.

Upregulation of polycistronic microRNA-143 and microRNA-145 in colonocytes suppresses colitis and inflammation-associated colon cancer

ABSTRACT Because ADAM17 promotes colonic tumorigenesis, we investigated potential miRNAs regulating ADAM17; and examined effects of diet and tumorigenesis on these miRNAs. We also examined pre-miRNA processing and tumour suppressor roles of several of these miRNAs in experimental colon cancer. Using TargetScan, miR-145, miR-148a, and miR-152 were predicted to regulate ADAM17. miR-143 was also investigated as miR-143 and miR-145 are co-transcribed and associated with decreased tumour growth. HCT116 colon cancer cells (CCC) were co-transfected with predicted ADAM17-regulating miRNAs and luciferase reporters controlled by ADAM17-3’UTR. Separately, pre-miR-143 processing by colonic cells was measured. miRNAs were quantified by RT-PCR. Tumours were induced with AOM/DSS in WT and transgenic mice (Tg) expressing pre-miR-143/miR-145 under villin promoter. HCT116 transfection with miR-145, −148a or −152, but not scrambled miRNA inhibited ADAM17 expression and luciferase activity. The latter was suppressed by mutations in ADAM17-3’UTR. Lysates from colonocytes, but not CCC, processed pre-miR-143 and mixing experiments suggested CCC lacked a competency factor. Colonic miR-143, miR-145, miR-148a, and miR-152 were downregulated in tumours and more moderately by feeding mice a Western diet. Tg mice were resistant to DSS colitis and had significantly lower cancer incidence and tumour multiplicity. Tg expression blocked up-regulation of putative targets of miR-143 and miR-145, including ADAM17, K-Ras, XPO5, and SET. miR-145, miR-148a, and miR-152 directly suppress colonocyte ADAM17 and are down-regulated in colon cancer. This is the first direct demonstration of tumour suppressor roles for miR-143 and miR-145 in an in vivo model of colonic tumorigenesis.

Expression levels of the metalloproteinase ADAM8 critically regulate proliferation, migration and malignant signalling events in hepatoma cells.

Hepatocellular carcinoma (HCC) is one of the most common metastatic tumours. Tumour growth and metastasis depend on the induction of cell proliferation and migration by various mediators. Here, we report that the A Disintegrin and Metalloproteinase (ADAM) 8 is highly expressed in murine HCC tissues as well as in murine and human hepatoma cell lines Hepa1‐6 and HepG2, respectively. To establish a dose‐dependent role of different ADAM8 expression levels for HCC progression, ADAM8 expression was either reduced via shRNA‐ or siRNA‐mediated knockdown or increased by using a retroviral overexpression vector. These two complementary approaches revealed that ADAM8 expression levels correlated positively with proliferation, clonogenicity, migration and matrix invasion and negatively with apoptosis of hepatoma cells. Furthermore, the analysis of pro‐migratory and proliferative signalling pathways revealed that ADAM8 expression level was positively associated with expression of β1 integrin as well as with the activation of focal adhesion kinase (FAK), mitogen‐activated protein kinase (MAPK), Src kinase and Rho A GTPase. Finally, up‐regulation of promigatory signalling and cell migration was also seen with a proteolytically inactive ADAM8 mutant. These findings reveal that ADAM8 is critically up‐regulated in hepatoma cells contributes to cell proliferation and survival and furthermore induces pro‐migratory signalling pathways independently of its proteolytic activity. By this, ADAM8 can promote cell functions most relevant for HCC growth and metastasis.

MicroRNA-1298 inhibits the malignant behaviors of breast cancer cells via targeting ADAM9.

MicroRNAs (miRNAs) regulate the progression of human malignancy by targeting oncogenes or tumor suppressors, which are 12 promising targets for cancer treatment. Increasing evidence has suggested the aberrant expression and tumor-suppressive function of miR-1298 in cancers, however, the regulatory mechanism of miR-1298 in breast cancer (BC) remains unclear. Here, our findings showed that miR-1298 was down-regulated in BC tissues and cell lines. Lower level of miR-1298 was significantly correlated with the advanced progression of BC patients. Experimental study showed that overexpression of miR-1298 inhibited the proliferation, induced apoptosis and cell cycle arrest in BC cells. The in vivo xenograft mice model showed that highly expressed miR-1298 significantly reduced the tumor growth and metastasis. Further mechanism analysis revealed that miR-1298 bound the 3′-untranslated region (UTR) of a disintegrin and metalloproteinase 9 domain (ADAM9) and suppressed the expression of ADAM9 in BC cells. ADAM9 was overexpressed in BC tissues and inversely correlated with miR-1298. Down-regulation of ADAM9 induced apoptosis and cell cycle arrest of BC cells. Moreover, ectopic expression of ADAM9 by transiently transfecting with vector encoding the full coding sequence of ADAM9 attenuated the inhibitory effects of miR-1298 on the proliferation and cell cycle progression of BC cells. Collectively, our results illustrated that miR-1298 played a suppressive role in regulating the phenotype of BC cells through directly repressing ADAM9, suggesting the potential application of miR-1298 in the therapy of BC.

Identification of Novel MicroRNAs as Promising Therapeutics for SARS-CoV-2 by Regulating the EGFR-ADAM17 Axis: An In Silico Analysis.

Cancer patients contracting SARS-CoV-2 encounter additional challenges due to inflammatory bursts and lymphopenia, which may aggravate breast cancer prognosis. In this in silico analysis, we identified the potential of miRNAs as new therapeutic targets to treat breast cancer patients infected with COVID-19 via the regulation of ADAM17 and EGFR expression microRNAs.

Interleukin 13 (IL-13)-regulated expression of the chondroprotective metalloproteinase ADAM15 is reduced in aging cartilage

ObjectiveThe adamalysin metalloproteinase 15 (ADAM15) has been shown to protect against development of osteoarthritis in mice. Here, we have investigated factors that control ADAM15 levels in cartilage. DesignSecretomes from wild-type and Adam15−/− chondrocytes were compared by label-free quantitative mass spectrometry. mRNA was isolated from murine knee joints, either with or without surgical induction of osteoarthritis on male C57BL/6 mice, and the expression of Adam15 and other related genes quantified by RT-qPCR. ADAM15 in human normal and osteoarthritic cartilage was investigated similarly and by fluorescent immunohistochemistry. Cultured HTB94 chondrosarcoma cells were treated with various anabolic and catabolic stimuli, and ADAM15 mRNA and protein levels evaluated. ResultsThere were no significant differences in the secretomes of chondrocytes from WT and Adam15−/− cartilage. Expression of ADAM15 was not altered in either human or murine osteoarthritic cartilage relative to disease-free controls. However, expression of ADAM15 was markedly reduced upon aging in both species, to the extent that expression in joints of 18-month-old mice was 45-fold lower than in that 4.5-month-old animals. IL-13 increased expression of ADAM15 in HTB94 ​cells by 2.5-fold, while modulators of senescence and autophagy pathways had no effect. Expression of Il13 in the joint was reduced with aging, suggesting this cytokine may control ADAM15 levels in the joint. ConclusionExpression of the chondroprotective metalloproteinase ADAM15 is reduced in aging human and murine joints, possibly due to a concomitant reduction in IL-13 expression. We thus propose IL-13 as a novel factor contributing to increased osteoarthritis risk upon aging.

The emerging role of the MiR-1272-ADAM9-CDCP1 signaling pathway in the progression of glioma.

Glioma is a primary, malignant, and aggressive brain tumor in adults. To develop new therapeutic strategies for glioma, we must determine its underlying mechanisms. In the present study, we aimed to investigate the potential role of miR-1272-ADAM9-CDCP1 signaling in the progression of glioma. We found that ectopic expression of miR-1272 produced significant inhibitory effects on cell proliferation and migration and was associated with cell cycle G0/G1 arrest in A172 and SHG44 glioma cells. Using the luciferase reporter assay, we identified ADAM9 as a target of miR-1272. The expression of ADAM9 was markedly decreased or increased after overexpression or inhibition, respectively, of miR-1272 in glioma cells. Moreover, overexpression of ADAM9 reversed the inhibitory effects of miR-1272 on glioma cell progression. Furthermore, CDCP1 served as a potential downstream molecule of miR-1272/ADAM9 signaling in glioma and promoted the proliferation and migration of glioma. Results derived from clinical samples and online databases confirmed correlations between the expression of ADAM9 and CDCP1 and both the severity and prognosis of glioma. In conclusion, these results suggest that miR-1272 and CDCP1 may act as novel regulators in glioma. The miR-1272/ADAM9/CDCP1 pathway may serve as a potential candidate pathway for the prevention of glioma.

Luteolin alters MUC1 extracellular domain, sT antigen, ADAM-17, IL-8, IL-10 and NF-κB expression in Helicobacter pylori-infected gastric cancer CRL-1739 cells: A preliminary study.

Luteolin is a natural flavonoid possessing certain beneficial pharmacological properties, including anti-oxidant, anti-inflammatory, anti-microbial and anti-cancer properties. The majority of types of gastric cancer with chronic gastritis are caused by infection with Helicobacter pylori (H. pylori). The present study evaluated the effect of luteolin on a number of selected factors that are potentially involved in gastric cancer development. The study was performed using gastric cancer CRL-1739 cells treated with 30 µM luteolin and H. pylori alone or combined. ELISA and reverse transcription PCR were used to assess the expression levels of MUC1, GalNAcα-R (Tn antigen) and NeuAcα2-3Galβ1-3GalNAc-R (sT antigen), ADAM-17, IL-8, IL-10 and NF-κB. H. pylori and luteolin independently and in combination significantly reduced the expression levels of the extracellular domain of MUC1 in gastric cancer cells compared with the untreated control cells. ADAM-17 expression was reduced by treatment with the pathogen and luteolin. Additionally, both factors reduced sT antigen expression. Treatment with 30 ≤M luteolin significantly induced IL-8 expression at the mRNA and protein level, and the mRNA expression levels of IL-10 and NF-κB compared with the control. Both H. pylori and luteolin induced IL-8 protein expression. The present preliminary results suggest that luteolin may be used to treat patients with gastric cancer.

ADAM10 inhibition improves survival and augments cardiac function after myocardial infarction

Abstract Background and purpose Following myocardial infarction (MI), adverse fibrotic remodeling with extensive deposition of extracellular matrix (ECM) components has substantial consequences for the contractility of the ventricle finally leading to terminal heart failure (HF). Recently, inhibition of ECM-remodeling enzymes is discussed as potential treatment option for HF, especially following MI. The metalloprotease ADAM10 plays a crucial role in the development of the cardiovascular system and HF patients show elevated serum levels of the ADAM10 substrates CXCL16 and FasL. However, the causal role of ADAM10 in cardiovascular diseases has not been investigated. Here we evaluate the so far unknown role of ADAM10 in heart failure and after MI. Methods and results Our study capitalized from human atrial tissue biopsies, a cardiomyocyte-specific ADAM10 knockout (ADAM10 KO) mouse model as well as pharmacological ADAM10 inhibition following MI. ADAM10 expression analysis revealed elevated protein levels in HF patients compared to non-failing hearts. Upon MI, ADAM10 KO and pharmacological ADAM10 inhibition (GI254023X) significantly improved overall survival, significantly enhanced cardiac function (fractional area shortening - FAS, ejection fraction - EF) and significantly reduced infarct sizes. Compared to the high potential angiotensin receptor neprilysin inhibitor (ARNi) LCZ696, ADAM10 inhibition and combined ADAM10i/LCZ696 treatment resulted in preservation of cardiac function that was superior to sole LCZ696 treatment. Mechanistically, this functional improvement was due to reduced shedding of the ADAM10 substrate Notch1, induction of angiogenesis and an ADAM10-dependend inactivation of the NLRP3 inflammasome Conclusion Our data suggest that ADAM10 targeting is highly efficient for improving post-infarction cardiac function. Due to its overexpression in heart tissue of HF patients, ADAM10 could be a potential molecular target to improve therapy after MI. In terms of overall survival and pathophysiological remodeling following MI, our data suggest a greater potential of the ADAM10i/LCZ696 combinatorial therapy than sole LCZ696 treatment. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): German Heart Foundation/ German Foundation of Heart Research

β2-AR activation promotes cleavage and nuclear translocation of Her2 and metastatic potential of cancer cells.

Prolonged hypersecretion of catecholamine induced by chronic stress may correlate with malignant progression of cancer. β2‐adrenergic receptor (β2‐AR) overexpressed in certain cancer cells may translate the signals from neuroendocrine system to malignant signals by interacting with oncoproteins, such as Her2. In the present study, we demonstrate that catecholamine stimulation activates the expression and proteolytic activity of ADAM10 by modulating the expression of miR‐199a‐5p and SIRT1 and also confirm that catecholamine induction triggers the activities of γ‐secretase, leading to shedding of Her2 extracellular domain (ECD) by ADAM10 and subsequent intramembranous cleavage of Her2 intracellular domain (ICD) by presenilin‐dependent γ‐secretase, nuclear translocation of Her2 ICD, and enhanced transcription of tumor metastasis‐associated gene COX‐2. Chronic stimulation of catecholamine strongly promotes the invasive activities of cancer cells in vitro and spontaneous tumor lung metastasis in mice. Furthermore, nuclear localization of Her2 was significantly correlated with overexpression of β2‐AR in human breast cancer tissues, indicating that catecholamine‐induced β2‐AR activation plays decisive roles in tumor metastasis. Our data also reveal that an unknown mechanism by which the regulated intramembrane proteolysis (RIP) initiated by β2‐AR‐mediated signaling controls a novel Her2‐mediated signaling transduction.

Blocking glycine receptors reduces neuroinflammation and restores neurotransmission in cerebellum through ADAM17-TNFR1-NF-\u03ba\u03b2 pathway

BackgroundChronic hyperammonemia induces neuroinflammation in cerebellum, with glial activation and enhanced activation of the TNFR1-NF-kB-glutaminase-glutamate-GABA pathway. Hyperammonemia also increases glycinergic neurotransmission. These alterations contribute to cognitive and motor impairment. Activation of glycine receptors is reduced by extracellular cGMP, which levels are reduced in cerebellum of hyperammonemic rats in vivo.We hypothesized that enhanced glycinergic neurotransmission in hyperammonemic rats (1) contributes to induce neuroinflammation and glutamatergic and GABAergic neurotransmission alterations; (2) is a consequence of the reduced extracellular cGMP levels. The aims were to assess, in cerebellum of hyperammonemic rats, (a) whether blocking glycine receptors with the antagonist strychnine reduces neuroinflammation; (b) the cellular localization of glycine receptor; (c) the effects of blocking glycine receptors on the TNFR1-NF-kB-glutaminase-glutamate-GABA pathway and microglia activation; (d) whether adding extracellular cGMP reproduces the effects of strychnine.MethodsWe analyzed in freshly isolated cerebellar slices from control or hyperammonemic rats the effects of strychnine on activation of microglia and astrocytes, the content of TNFa and IL1b, the surface expression of ADAM17, TNFR1 and transporters, the phosphorylation levels of ERK, p38 and ADAM17. The cellular localization of glycine receptor was assessed by immunofluorescence. We analyzed the content of TNFa, IL1b, HMGB1, glutaminase, and the level of TNF-a mRNA and NF-κB in Purkinje neurons. Extracellular concentrations of glutamate and GABA were performed by in vivo microdialysis in cerebellum. We tested whether extracellular cGMP reproduces the effects of strychnine in ex vivo cerebellar slices.ResultsGlycine receptors are expressed mainly in Purkinje cells. In hyperammonemic rats, enhanced glycinergic neurotransmission leads to reduced membrane expression of ADAM17, resulting in increased surface expression and activation of TNFR1 and of the associated NF-kB pathway. This increases the expression in Purkinje neurons of TNFa, IL-1b, HMGB1, and glutaminase. Increased glutaminase activity leads to increased extracellular glutamate, which increases extracellular GABA. Increased extracellular glutamate and HMGB1 potentiate microglial activation. Blocking glycine receptors with strychnine or extracellular cGMP completely prevents the above pathway in hyperammonemic rats.ConclusionsGlycinergic neurotransmission modulates neuroinflammation. Enhanced glycinergic neurotransmission in hyperammonemia would be due to reduced extracellular cGMP. These results shed some light on possible new therapeutic target pathways for pathologies associated to neuroinflammation.

Loss of ADAM9 Leads to Modifications of the Extracellular Matrix Modulating Tumor Growth.

ADAM9 is a metalloproteinase strongly expressed at the tumor-stroma border by both tumor and stromal cells. We previously showed that the host deletion of ADAM9 leads to enhanced growth of grafted B16F1 melanoma cells by a mechanism mediated by TIMP1 and the TNF-α/sTNFR1 pathway. This study aimed to dissect the structural modifications in the tumor microenvironment due to the stromal expression of ADAM9 during melanoma progression. We performed proteomic analysis of peritumoral areas of ADAM9 deleted mice and identified the altered expression of several matrix proteins. These include decorin, collagen type XIV, fibronectin, and collagen type I. Analysis of these matrices in the matrix producing cells of the dermis, fibroblasts, showed that ADAM9−/− and wild type fibroblasts synthesize and secreted almost comparable amounts of decorin. Conversely, collagen type I expression was moderately, but not significantly, decreased at the transcriptional level, and the protein increased in ADAM9−/− fibroblast mono- and co-cultures with melanoma media. We show here for the first time that ADAM9 can release a collagen fragment. Still, it is not able to degrade collagen type I. However, the deletion of ADAM9 in fibroblasts resulted in reduced MMP-13 and -14 expression that may account for the reduced processing of collagen type I. Altogether, the data show that the ablation of ADAM9 in the host leads to the altered expression of peritumoral extracellular matrix proteins that generate a more favorable environment for melanoma cell growth. These data underscore the suppressive role of stromal expression of ADAM9 in tumor growth and call for a better understanding of how protease activities function in a cellular context for improved targeting.

MiRNA-488-3p inhibits malignant progression of NSCLC by modulating ADAM9.

The purpose of this study was to investigate the role of microRNA-488-3p in the proliferation, invasion and migration of lung cancer cells and to further explore the potential regulatory mechanisms. MicroRNA-488-3p expression in 46 pairs of tumor tissue and paracancerous tissue specimens collected from non-small cell lung cancer (NSCLC) patients were measured through quantitative real-time polymerase chain reaction (qRT-PCR) method, and the interplay between microRNA-488-3p expression and some clinical indicators of these subjects was also analyzed. In addition, microRNA-488-3p overexpression models were constructed in NSCLC cell lines, and then Cell Counting Kit-8 (CCK-8) test and transwell assays were carried out to evaluate the effect of microRNA-488-3p on the NSCLC cell functions. Furthermore, bioinformatics analysis and luciferase reporter gene assay were carried out to uncover the potential interaction between microRNA-488-3p and its downstream gene ADAM9. QPCR results revealed that microRNA-488-3p showed a significant lower expression in NSCLC tissue samples than in adjacent normal ones. In comparison to patients with high expression of microRNA-488-3, patients with low expression of microRNA-488-3 exhibited higher incidence of lymph node or distant metastasis and lower survival rate. In vitro cell experiments showed that, in comparison to control group, overexpression of microRNA-488-3p significantly weakened the proliferation ability as well as the invasion and migration of NSCLC cells. Subsequently, a significant increase in ADAM9 expression in NSCLC tissue samples was found, which indicated its negative correlation with microRNA-488-3p. In addition, cell recovery experiment demonstrated that overexpression of ADAM9 could counteract the impact of microRNA-488-3p upregulation on the proliferation and invasion ability of NSCLC cells, and the two may thus together affect the malignant progression of NSCLC. It can be concluded that microRNA-488-3p, which is associated with the incidence of metastasis in NSCLC patients, can inhibit the malignant progression of NSCLC cells by modulating ADAM9 expression.