A Disintegrin And Metalloprotease 10 Expression Research Articles

A Disintegrin And Metalloprotease 10 expression within the murine central nervous system

A Disintegrin And Metalloprotease 10 (ADAM10), is able to control several important physiopathological processes through the shedding of a large number of protein substrates. Although ADAM10 plays a crucial role in the central nervous system (CNS) development and function, its protein distribution in the CNS has not been fully addressed. Here, we described the regional and cellular ADAM10 protein expression in C57BL/6 mice examined by immunofluorescence 1) throughout the adult mouse brain, cerebellum and spinal cord in vivo and 2) in different cell types as neurons, astrocytes, oligodendrocytes and microglia in vitro. We observed ADAM10 expression through the whole CNS, with a strong expression in the hippocampus, in the hypothalamus and in the cerebral and piriform cortex in the brain, in the Purkinje and in granular cell layers in the cerebellum and in the spinal cord to a lower extent. In vivo, ADAM10 protein expression was mainly found in neurons and in some oligodendroglial cell populations. However, in primary cultures we observed ADAM10 expression in neurons, oligodendrocytes, astrocytes and microglia. Interestingly, ADAM10 was not only found in the membrane but also in cytoplasmic vesicles and in the nucleus of primary cultured cells. Overall, this work highlights a wide distribution of ADAM10 throughout the CNS. The nuclear localization of ADAM10, probably due to its intracellular domain, emphasizes its role in cell signalling in physiological and pathological conditions. Further investigations are required to better elucidate the role of ADAM10 in glial cells.

The Autism Spectrum Disorder-Associated Bacterial Metabolite p-Cresol Derails the Neuroimmune Response of Microglial Cells Partially via Reduction of ADAM17 and ADAM10.

The bacterial metabolite 4-methylphenol (para-cresol or p-cresol) and its derivative p-cresyl sulfate (pCS) are elevated in the urine and feces of children with autism spectrum disorder (ASD). It has been shown that p-cresol administration induces social behavior deficits and repetitive behavior in mice. However, the mechanisms of p-cresol, specifically its metabolite pCS that can reach the brain, in ASD remain to be investigated. The pCS has been shown to inhibit LPS-stimulated inflammatory response. A Disintegrin And Metalloprotease 10 (ADAM10) and A Disintegrin And Metalloprotease 17 (ADAM17) are thought to regulate microglial immune response by cleaving membrane-bound proteins. In the present study, a neuroinflammation model of LPS-activated BV2 microglia has been used to unveil the potential molecular mechanism of pCS in ASD pathogenesis. In microglial cells pCS treatment decreases the expression or maturation of ADAM10 and ADAM17. In addition, pCS treatment attenuates TNF-α and IL-6 releases as well as phagocytosis activity of microglia. In in vitro ADAM10/17 inhibition experiments, either ADAM10 or ADAM17 inhibition reduces constitutive and LPS-activated release of TNF-α, TNFR-1 and IL-6R by microglial cells, while it increases constitutive and LPS-activated microglial phagocytotic activity. The in vivo results further confirm the involvement of ADAM10 and ADAM17 in ASD pathogenesis. In in utero VPA-exposed male mice, elevated concentration in serum of p-cresol-associated metabolites pCS and p-cresyl glucuronide (pCG) is associated with a VPA-induced increased ADAM10 maturation, and a decreased ADAM17 maturation that is related with attenuated levels of soluble TNF-α and TGF-β1 in the mice brain. Overall, the present study demonstrates a partial role of ADAM10 and ADAM17 in the derailed innate immune response of microglial cells associated with pCS-induced ASD pathogenesis.

ADAM-10 Regulates MMP-12 during Lipopolysaccharide-Induced Inflammatory Response in Macrophages.

A disintegrin and metalloprotease 10 (ADAM-10), a member of the ADAM protease family, has biological activities related to TNF-α activation, cell adhesion, and migration, among other functions. Macrophages are important immune cells that are involved in the inflammatory response of the body. ADAM-10 is involved in inflammatory responses, but the specific regulatory mechanisms are not fully understood. In this study, we investigated the regulatory mechanism of ADAM-10 in the lipopolysaccharide-promoted proliferation (LPS) of the macrophage inflammatory response. Differentially expressed or regulated proteins were identified in interfered ADAM-10 (sh ADAM-10) macrophages using tandem mass tag (TMT) proteomics. The changes and regulatory role of ADAM-10 during LPS-induced inflammatory response in normal, interfering, and overexpressing ADAM-10 (EX ADAM-10) cells were determined. Results indicated that ADAM-10 interference affected inflammation-related pathways and reduced matrix metalloproteinase 12 (MMP-12) protein levels, as identified by TMT proteomics. In normal cells, LPS decreased ADAM-10 gene expression, but promoted ADAM-10 secretion, MMP-12 and TNF-α gene expression, and MMP-12, iNOS, IL-10, and cyclinD1 protein expression. Additionally, ADAM-10 knockdown decreased macrophage viability in sh-ADAM-10 cells. Moreover, an MMP-12 inhibitor had no impact on the viability effect of LPS on cells or the expression of ADAM-10. iNOS expression decreased, whereas IL-10 expression increased after ADAM-10 depletion. ADAM-10 knockdown decreased MMP-12, iNOS, TNF-α, IL-1β, and FKN, while overexpression had an opposite effect. ADAM-10 overexpression further increased MMP-12, iNOS, and TNF-α gene expression in response to LPS. Cell viability was increased in EX ADAM-10 cells, and ADAM-10 secretion was further increased in the EX and LPS groups. Flow cytometry and immunofluorescence staining revealed that EX-ADAM 10 cells had increased iNOS expression, which acted as an IL-6 expression driver. In summary, we found that ADAM-10 is activated by LPS and positively participates in LPS-stimulated macrophage inflammatory responses by positively regulating MMP-12 during the inflammatory process.

Effect of type 2 diabetes on A disintegrin and metalloprotease 10.

BackgroundAs a type 1 transmembrane protein, a disintegrin and metalloprotease 10 (ADAM10) is responsible for the cleavage of a variety of cell surface molecules and has been implicated in the pathogenesis of Alzheimer disease, atherosclerosis, and inflammatory and neoplastic disorders. It has been suggested that systemic ADAM10 concentration may potentially be used as a prognostic biomarker. Since high glucose can upregulate ADAM10 expression in vitro, we investigated whether serum levels of ADAM10 and its substrate, the lectin‐like oxidized low‐density lipoprotein receptor 1 (LOX‐1), can be influenced by type 2 diabetes.MethodsA total of 1091 individuals with type 2 diabetes and 358 age‐matched healthy control subjects were recruited. Serum concentrations of ADAM10 and the soluble form of LOX‐1 (sLOX‐1) released by cleavage of LOX‐1 by ADAM were measured by enzyme‐linked immunosorbent assay kits (ELISA).ResultsSerum ADAM10 was increased in subjects with diabetes compared with control (40.5 ng/mL [22.3‐65.7] vs 10.3 ng/mL [7.0‐17.9], respectively; P < .01); the highest levels were seen in insulin‐treated subjects. On multiple linear regression analysis, glycosylated hemoglobin, age, body mass index, and insulin use were independent determinants of ADAM10 level. The increase in serum ADAM10 levels in diabetes was accompanied by changes in serum sLOX‐1. Subjects with diabetes had higher serum sLOX‐1 than the control (110 pg/mL [89‐153] vs 104 pg/mL [85‐138], respectively; P < .01), and there was a significant correlation between serum ADAM10 and sLOX‐1 (r = 0.26, P < .01).ConclusionsSerum concentration of ADAM10 is increased in type 2 diabetes and is associated with glycemia and insulin therapy, which may potentially affect the specificity of systemic ADAM10 level as a biomarker.

ADAM10-cleaved ephrin-A5 contributes to prostate cancer metastasis

A disintegrin and metalloprotease-10(ADAM10) promotes the metastasis of prostate cancer (PCa), but the specific mechanism is indistinct. Herein, DU145 cell lines with stable overexpression and knockdown of ADAM10 were constructed. We found that ectopic expression of ADAM10 not only significantly facilitated cell proliferation, migration, invasion, and inhibited apoptosis, but also could specifically hydrolyze ephrin-A5 and release the ephrin-A5 soluble ectodomain into extracellular media in vitro. These effects were reversed by ADAM10 depletion or treatment of GI254023X. Meanwhile, the co-location and physical interaction among EphA3, ephrin-A5, and ADAM10 were observed in PCa cells using immunofluorescence and immunoprecipitation techniques. Interestingly, overexpression of EphA3 exerted opposite effects in DU145 (ephrin-A5 + ) cells and PC-3 (ephrin-A5 ± ) cells. In addition, the pro-tumor function of EphA3 was reversed by the treatment with the exogenous ephrin-A5-Fc, which increased the phosphorylation level of EphA3 in PC-3 (ephrin-A5 ± ) cells. In nude mice, ADAM10 accelerated growth of the primary tumor, decreased the level of ephrin-A5 in the tumor tissue, but increased the level of ephrin-A5 in the peripheral blood, accompanied with an increase in the expression of CD31 and VEGF (vascular endothelial growth factor) in the tissue. What is more, the serum ephrin-A5 content of patients with metastatic PCa was significantly higher than that of the non-metastatic group (P < 0.05). The receiver operating characteristic curve(ROC) showed that the area under the curve(AUC) of serum ephrin-A5 as a marker of PCa metastasis was 0.843, with a sensitivity of 93.5% and a specificity of 75%. It is concluded that ADAM10-mediated ephrin-A5 shedding promotes PCa metastasis via transforming the role of EphA3 from ligand-dependent tumor suppressor to ligand-independent promoter, and ephrin-A5 in the blood can be used as a new biomarker for PCa metastasis.

IDO1 can impair NK cells function against non-small cell lung cancer by downregulation of NKG2D Ligand via ADAM10

Indoleamine 2,3-dioxygenase 1 (IDO1) catalyzes the rate-limiting step in tryptophan catabolism along the kynurenine (Kyn) pathway and exerts immunosuppressive properties mainly via activation of transcription factor aryl hydrocarbon receptor (AhR) pathway. IDO1 induces NK cells dysfunction via downregulation of the activating receptor NKG2D on NK cells, but whether and how it affects the expression of NKG2D Ligand (NKG2DL) on tumor cells remains unclear. Since a disintegrin and metalloprotease 10 (ADAM10) plays a potential role in the shedding of NKG2DL and the releasing of soluble NKG2DL (sNKG2DL), we investigated how IDO1 modulates the expression of NKG2DL via ADAM10 in non-small cell lung cancer (NSCLC). We found that IDO1 expression was negatively correlated with NKG2DL expression while positively correlated with ADAM10 expression with human lung cancer brain metastasis tissue, NSCLC cells and LLC tumor-bearing mice. IDO1 could regulate ADAM10 expression via IDO1-Kyn-AhR signaling pathway and subsequently regulate NKG2DL expression. IDO1 deficiency led to retarded tumor growth and improved NK cells function in NSCLC mice. IDO1 inhibitors improved NK cells function in vitro and in vivo. The combo of IDO1 inhibitor and NK cells exhibited more therapeutic efficacy than either of the single IDO1 inhibitor or NK cells treatment.

Induction of ADAM10 by Radiation Therapy Drives Fibrosis, Resistance, and Epithelial-to-Mesenchyal Transition in Pancreatic Cancer.

Stromal fibrosis activates prosurvival and proepithelial-to-mesenchymal transition (EMT) pathways in pancreatic ductal adenocarcinoma (PDAC). In patient tumors treated with neoadjuvant stereotactic body radiation therapy (SBRT), we found upregulation of fibrosis, extracellular matrix (ECM), and EMT gene signatures, which can drive therapeutic resistance and tumor invasion. Molecular, functional, and translational analysis identified two cell-surface proteins, a disintegrin and metalloprotease 10 (ADAM10) and ephrinB2, as drivers of fibrosis and tumor progression after radiation therapy (RT). RT resulted in increased ADAM10 expression in tumor cells, leading to cleavage of ephrinB2, which was also detected in plasma. Pharmacologic or genetic targeting of ADAM10 decreased RT-induced fibrosis and tissue tension, tumor cell migration, and invasion, sensitizing orthotopic tumors to radiation killing and prolonging mouse survival. Inhibition of ADAM10 and genetic ablation of ephrinB2 in fibroblasts reduced the metastatic potential of tumor cells after RT. Stimulation of tumor cells with ephrinB2 FC protein reversed the reduction in tumor cell invasion with ADAM10 ablation. These findings represent a model of PDAC adaptation that explains resistance and metastasis after RT and identifies a targetable pathway to enhance RT efficacy. SIGNIFICANCE: Targeting a previously unidentified adaptive resistance mechanism to radiation therapy in PDAC tumors in combination with radiation therapy could increase survival of the 40% of PDAC patients with locally advanced disease.See related commentary by Garcia Garcia et al., p. 3158 GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/12/3255/F1.large.jpg.

Human umbilical cord mesenchymal stem cells-derived exosomal microRNA-451a represses epithelial–mesenchymal transition of hepatocellular carcinoma cells by inhibiting ADAM10

ABSTRACT Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs) expressing microRNAs (miRNAs) have been highlighted in human cancers. However, the detailed molecular mechanism of hucMSCs-derived exosomal miR-451a on hepatocellular carcinoma (HCC) remains further investigation. Our study aims to explore the impact of exosomal miR-451a on the progression of HCC. Expression of miR-451a and a disintegrin and metalloprotease 10 (ADAM10) in HCC tissues and adjacent normal tissues were determined. The exosomes were extracted from hucMSCs and co-cultured with Hep3B and SMMC-7721 cell lines. After the treatment of relative exosomes or exosome inhibitor GW4869 in Hep3B and SMMC-7721 cells, the paclitaxel resistance and malignant phenotypes of HCC cells were measured. Moreover, the effect of hucMSCs-derived exosomes on the expression of miR-451a and ADAM10 in HCC cells was assessed. The targeting relationship between miR-451a and ADAM10 was verified to detect the impact of ADAM10-wild type and ADAM10-mutant type (MUT) on HCC cell processes. Low expression of miR-451a and high expression of ADAM10 indicated a poor prognosis of HCC patients. MiR-451a was up-regulated while ADAM10 was down-regulated in HCC cells after co-culture with HucMSC-derived exosomes. The exosomes elevated miR-451a and inhibited ADAM10 to suppress the paclitaxel resistance, cell cycle transition, proliferation, migration and invasion, and promote apoptosis of HCC cells. ADAM10 was verified to be a target gene of miR-451a. ADAM10-MUT promoted HCC process independent of miR-451a mimic. HucMSC-derived exosomal miR-451a could restrict the epithelial–mesenchymal transition of HCC cells by targeting ADAM10, which might provide new targets for HCC treatment.

Long non-coding RNA CDKN2B-AS1 reduces inflammatory response and promotes cholesterol efflux in atherosclerosis by inhibiting ADAM10 expression.

Introduction: Long non-coding RNAs (lncRNAs) play key roles in the development of atherosclerosis through the inflammatory pathway. This study aimed to investigate the role of lncRNA cyclin-dependent kinase inhibitor 2B antisense RNA 1 (CDKN2B-AS1) in atherosclerosis via its function in A disintegrin and metalloprotease 10 (ADAM10).Methods: Initially, the expression of CDKN2B-AS1 and ADAM10 in atherosclerotic plaque tissues and THP-1 macrophage-derived foam cells was determined, after which the cholesterol efflux rate of macrophages was calculated. Interaction between CDKN2B-AS1 and ADAM10 was analyzed, after which, expression of CDKN2B-AS1 and ADAM10 were altered to explore their effects on inflammatory response and cholesterol efflux. The aforementioned findings were further intended to be validated by the atherosclerosis mouse model experiments.Results: Atherosclerotic plaque tissue and THP-1 macrophage-derived foam cells exhibited downregulated CDKN2B-AS1 and upregulated ADAM10. Upon overexpressing CDKN2B-AS1 or silencing ADAM10, lipid accumulation was reduced and cholesterol efflux was increased. CDKN2B-AS1 located in the nucleus could bind to DNA methyltransferase 1 (DNMT1) to enhance methylation of ADAM10 promoter, leading to suppressed atherosclerotic inflammatory response and promoted cholesterol efflux.Conclusion: Altogether, lncRNA CDKN2B-AS1 can inhibit the transcription of ADAM10 via DNMT1-mediated ADAM10 DNA methylation, consequently preventing inflammatory response of atherosclerosis and promoting cholesterol efflux.

A disintegrin and metalloprotease 10-containing exosomes derived from nasal polyps promote angiogenesis and vascular permeability.

Abnormal angiogenesis and vascular permeability is important for the formation of nasal polyps (NPs). Increasing evidence has indicated that exosomes serve a vital role in modulating angiogenesis and vascular permeability. A disintegrin and metalloprotease 10 (ADAM10), an important type of proteinase that is overexpressed in various diseases, can influence angiogenesis and vascular permeability and has been observed in healthy nasal exosomes. To the best of our knowledge, the expression levels and the function of ADAM10 in NLF-derived exosomes from NPs has not been demonstrated previously. In order to determine the influence of exosomes derived from nasal lavage fluid (NLF) on angiogenesis and vascular permeability, 25 nasal polyp patients and 15 healthy volunteers were enrolled in the present study. NLF was collected from all of the subjects. Exosomes were isolated from NLF, visualized under transmission electron microscope and identified using western blot analysis. The effect of exosomes on human umbilical vein endothelial cells (HUVECs) was measured by tube formation and permeability assays in vitro. The expression of exosomal ADAM10 was also analyzed by western blotting. NLF-derived exosomes from NPs influenced proliferation, tube formation and the permeability of HUVECs. ADAM10 was highly expressed in NLF-derived exosomes from NPs when compared with healthy volunteers. Thus, NLF-derived exosomes from NPs promoted angiogenesis and vascular permeability, which may be associated with abundant ADAM10 in NP exosomes.

ADAM10 modulates calcitriol-regulated RAGE in cardiomyocytes.

Receptor for advanced glycation end products (RAGE) signalling plays a critical role in the pathogenesis of cardiovascular disease. Calcitriol modulates cardiac RAGE expression. This study explored the mechanisms underlying the effect of calcitriol on RAGE and soluble RAGE (sRAGE) expression in cardiomyocytes. Western blot, ELISA, fluorometric assay and PCR analyses were used to evaluate the RAGE, sRAGE, endogenous secretory RAGE (esRAGE), Jun N-terminal kinase (JNK), and a disintegrin and metalloprotease 10 (ADAM10) expression and enzyme activity in HL-1 atrial myocytes without and with calcitriol (10 and 100 nM), nuclear factor-κB (NF-κB) inhibitor (50 μg/mL), or ADAM10 inhibitor (5 μM) incubation for 48 h. Calcitriol (10 nM) significantly reduced RAGE protein expression and increased sRAGE concentrations in HL-1 cardiomyocytes compared with control cells. These changes were associated with increased protein expression and enzyme activity of ADAM10 and higher mRNA expression of esRAGE. In the presence of ADAM10 inhibitor, however, the suppressive effect of calcitriol on RAGE was diminished. Methylglyoxal (500 μM for 10 min)-mediated JNK phosphorylation was attenuated in the presence of calcitriol (10 nM). Moreover, control and NF-κB inhibitor-treated HL-1 cells had similar RAGE and sRAGE expression, suggesting that calcitriol-mediated RAGE modulation was independent of NF-κB signalling. We showed that RAGE downregulation and increased sRAGE production by calcitriol were mediated through ADAM10 activation in cardiomyocytes. The results suggest that calcitriol has therapeutic potential in treating RAGE-mediated cardiovascular complications.

MICRO-RNA 221 INHIBITS ADAM10 PROTEIN EXPRESSION IN SH-SY5Y CELLS

In Alzheimer's disease (AD) non-amyloidogenic pathway, A Disintegrin And Metalloprotease 10 (ADAM10) acts as α-secretase, avoiding amyloid β (Aβ) production. We propose to analyze the overexpression of miR-144–5p, miR-374 and miR-221 in SH-SY5Y cells and verify their ADAM10 protein expression correlation. The research project was approved by Brazil Ethics Platform (CAAE:02760312.0.0000.5504/112.543). Total blood of 21 AD subjects and 17 cognitively healthy elderly controls was collected and analyzed by RT-qPCR. Relative expression of approximately 700 miRNAs was performed and 21 miRNAs differentially expressed were validated. Among them, mir-144–5p, miR-374 and miR-221 were found to be downregulated in AD subjects compared to healthy controls. From this observation, we transiently transfected human neuroblastoma SH-SY5Y cells with mirVana™ mimics of three selected miRNAs. Cells were lysed and protein samples were analysed by western blotting using an anti-ADAM10 antibody. ADAM10 and endogen control (β-actin) protein expression were quantified and the adjusted volume was used to determine the arbitrary units (AU) of ADAM10 expression. ADAM10 protein levels are significantly decreased upon transient overexpression of miR-221 in SH-SY5Y cells, but not altered after overexpression of miR-144–5p and miR-374, indicating the specificity of miR-221 in the regulation of ADAM10 levels. These findings place the miR-221 as a potential blood-based biomarker for AD. Moreover, the inhibition of miRNA-221 can be a new potential therapeutic target for increasing ADAM10 in AD, thus avoiding Aβ production.

Ionizing radiation reduces ADAM10 expression in brain microvascular endothelial cells undergoing stress-induced senescence

Cellular senescence is associated with aging and is considered a potential contributor to age-associated neurodegenerative disease. Exposure to ionizing radiation increases the risk of developing premature neurovascular degeneration and dementia but also induces premature senescence. As cells of the cerebrovascular endothelium are particularly susceptible to radiation and play an important role in brain homeostasis, we investigated radiation-induced senescence in brain microvascular endothelial cells (EC). Using biotinylation to label surface proteins, streptavidin enrichment and proteomic analysis, we analyzed the surface proteome of stress-induced senescent EC in culture. An array of both recognized and novel senescence-associated proteins were identified. Most notably, we identified and validated the novel radiation-stimulated down-regulation of the protease, a disintegrin and metalloprotease 10 (ADAM10). ADAM10 is an important modulator of amyloid beta protein production, accumulation of which is central to the pathologies of Alzheimer's disease and cerebral amyloid angiopathy. Concurrently, we identified and validated increased surface expression of ADAM10 proteolytic targets with roles in neural proliferation and survival, inflammation and immune activation (L1CAM, NEO1, NEST, TLR2, DDX58). ADAM10 may be a key molecule linking radiation, senescence and endothelial dysfunction with increased risk of premature neurodegenerative diseases normally associated with aging.

Overexpression of A disintegrin and metalloprotease 10 promotes tumor proliferation, migration and poor prognosis in hypopharyngeal squamous cell carcinoma.

The aim of this study was to determine the effect of A disintegrin and metalloprotease 10 (ADAM10) protein expression on the progression, migration and prognosis of hypopharyngeal squamous cell carcinoma (HSCC). Immunohistochemistry and western blot analysis were performed to detect ADAM10 expression in human HSCC specimens. Cell Counting Kit-8 (CCK-8) assay, flow cytometry analysis and wound-healing assay were employed to investigate the effects of ADAM10 knockdown (ADAM10-RNAi) on major oncogenic properties of FaDu cells. We detected that ADAM10 was overexpressed in HSCC specimens and its expression level was associated with differentiation (p<0.001), tumor size (p=0.019), lymph node metastasis (p=0.001), clinical stage (p<0.001), proliferation marker Ki-67 expression (P=0.001) and overall survival (p<0.046). ADAM10-RNAi in FaDu cells resulted in the inhibition of proliferation and the decrease in migration. Moreover, mechanistic experiments revealed that ADAM10-RNAi resulted in an increase in E-cadherin and a decrease in N-cadherin and vimentin expression. Our study implies that high expression of ADAM10 promotes the proliferation and migration of HSCC. These findings may help to provide a method for treatment of HSCC.

Intranasal Lactoferrin Enhances α-Secretase-Dependent Amyloid Precursor Protein Processing via the ERK1/2-CREB and HIF-1α Pathways in an Alzheimer's Disease Mouse Model.

Growing evidence suggests that lactoferrin (Lf), an iron-binding glycoprotein, is a pleiotropic functional nutrient. In addition, Lf was recently implicated as a neuroprotective agent. These properties make Lf a valuable therapeutic candidate for the treatment of Alzheimer's disease (AD). However, the mechanisms regulating the physiological roles of Lf in the pathologic condition of AD remain unknown. In the present study, an APPswe/PS1DE9 transgenic mouse model of AD was used. We explored whether intranasal human Lf (hLf) administration could reduce β-amyloid (Aβ) deposition and ameliorate cognitive decline in this AD model. We found that hLf promoted the non-amyloidogenic metabolism of amyloid precursor protein (APP) processing through activation of α-secretase a-disintegrin and metalloprotease10 (ADAM10), resulting in enhanced cleavage of the α-COOH-terminal fragment of APP and the corresponding elevation of the NH2-terminal APP product, soluble APP-α (sAPPα), which consequently reduced Aβ generation and improved spatial cognitive learning ability in AD mice. To gain insight into the molecular mechanism by which Lf modulates APP processing, we evaluated the involvement of the critical molecules for APP cleavage and the signaling pathways in N2a cells stably transfected with Swedish mutant human APP (APPsw N2a cells). The results show that the ERK1/2-CREB and HIF-1α signaling pathways were activated by hLf treatment, which is responsible for the expression of induced ADAM10. Additional tests were performed before suggesting the potential use of hLf as an antioxidant and anti-inflammatory. These findings provide new insights into the sources and mechanisms by which hLf inhibits the cognitive decline that occurs in AD via activation of ADAM10 expression in an ERK1/2-CREB and HIF-1α-dependent manner.

Role of prostacyclin signaling in endothelial production of soluble amyloid precursor protein-α in cerebral microvessels

We tested hypothesis that activation of the prostacyclin (PGI2) receptor (IP receptor) signaling pathway in cerebral microvessels plays an important role in the metabolism of amyloid precursor protein (APP). In human brain microvascular endothelial cells activation of IP receptor with the stable analogue of PGI2, iloprost, stimulated expression of amyloid precursor protein and a disintegrin and metalloprotease 10 (ADAM10), resulting in an increased production of the neuroprotective and anticoagulant molecule, soluble APPα (sAPPα). Selective agonist of IP receptor, cicaprost, and adenylyl cyclase activator, forskolin, also enhanced expression of amyloid precursor protein and ADAM10. Notably, in cerebral microvessels of IP receptor knockout mice, protein levels of APP and ADAM10 were reduced. In addition, iloprost increased protein levels of peroxisome proliferator-activated receptor δ (PPARδ) in human brain microvascular endothelial cells. PPARδ-siRNA abolished iloprost-augmented protein expression of ADAM10. In contrast, GW501516 (a selective agonist of PPARδ) upregulated ADAM10 and increased production of sAPPα. Genetic deletion of endothelial PPARδ (ePPARδ−/−) in mice significantly reduced cerebral microvascular expression of ADAM10 and production of sAPPα. In vivo treatment with GW501516 increased sAPPα content in hippocampus of wild type mice but not in hippocampus of ePPARδ−/− mice. Our findings identified previously unrecognized role of IP-PPARδ signal transduction pathway in the production of sAPPα in cerebral microvasculature.

The expression pattern of Adam10 in the central nervous system of adult mice: Detection by in situ hybridization combined with immunohistochemistry staining.

ADAM10 (a disintegrin and metalloprotease 10) is a member of the ADAMs family, which is key in the development of the nervous system, by regulating proliferation, migration, differentiation and survival of various cells, including axonal growth and myelination. Previous studies have investigated the embryonic or postnatal expression of ADAM10, however, detailed information regarding its cellular distribution in the adult stage, to the best of our knowledge, is not available. The present study investigated the expression pattern of the ADAM10 gene in the adult mouse central nervous system (CNS) using an ADAM10 complementary RNA probe for in situ hybridization (ISH). Immunohistochemical staining was used to identify the type of the ISH staining-positive cells with neuron- or astrocyte-specific antibodies. The results of the current study demonstrated that the ADAM10 gene was predominantly expressed in the neurons of the cerebral cortex, hippocampus, thalamus and cerebellar granular cells in adult mouse CNS.

ADAM10 mediates the cell invasion and metastasis of human esophageal squamous cell carcinoma via regulation of E-cadherin activity.

A disintegrin and metalloprotease 10 (ADAM10) is involved in the tumorigenesis, invasion and metastasis of several types of solid tumors. However, the potential role of ADAM10 in human esophageal squamous cell carcinoma (ESCC) is not yet well understood. The present study showed that ADAM10 was overexpressed in human ESCC tissues in vivo, and positively associated with depth of tumor invasion, lymph node metastasis and TNM stage, contributing to tumor carcinogenesis, invasion and metastasis. Additionally, ADAM10 was overexpressed in 3 types of ESCC cell lines in vitro, as compared to that in normal esophageal epithelial cells (NEECs); and moreover, ESCC cells with high ADAM10 expression obtained enhanced invasion and migration ability. Subsequently, ADAM10 silencing by small interfering (si) RNA in ESCC cell line, EC-1, reduced cell invasion, migration and proliferation in vitro. Finally, ADAM10 negatively regulated E-cadherin in ESCC in vivo and in vitro. In conclusion, active ADAM10 promotes the carcinogenesis, invasion, metastasis and proliferation of ESCC and controls invasion and metastasis at least in part through the shedding of E-cadherin activity, which makes it a potential biomarker and a useful therapeutic target for ESCC.

Effects of ADAM10 upregulation on progression, migration, and prognosis of nasopharyngeal carcinoma.

A disintegrin and metalloprotease 10 (ADAM10) is a typical member of the ADAMs family, which has been reported to be upregulated in various types of cancers and contribute to cancer progression and metastasis. However, little is known about the role of ADAM10 in nasopharyngeal carcinoma (NPC). The purpose of this study is to explore ADAM10 expression status and its biological functions in NPC. We first examined the expression of ADAM10 in NPC tissues and cell lines by immunohistochemistry, Western blotting, PCR, and immunofluorescence analysis. We observed that ADAM10 was significantly elevated in NPC and its expression level was correlated with T classification (P = 0.044), distant metastasis (P = 0.016), TNM clinical stage (P = 0.013), and proliferation marker Ki-67 expression (P = 0.001). Patients with NPC with high expression of ADAM10 had shorter overall survival rates. In addition, knockdown of ADAM10 by RNAi was found to inhibit the CNE-2 cell proliferation and migration. Our findings hinted that overexpression of ADAM10 promotes the progression and migration of NPC, which makes it a potential therapeutic target for the treatment of tumor metastases in NPC.

Proteolytically active ADAM10 and ADAM17 carried on membrane microvesicles in human abdominal aortic aneurysms.

The intraluminal thrombus (ILT) of human abdominal aortic aneurysm (AAA) has been suggested to damage the underlying aortic wall, but previous work found scant activity of soluble proteases in the abluminal layer of the ILT, adjacent to the aneurysm. We hypothesised that transmembrane proteases carried by membrane microvesicles (MV) from dying cells remain active in the abluminal ILT. ILTs and AAA segments collected from 21 patients during surgical repair were assayed for two major transmembrane proteases, ADAM10 (a disintegrin and metalloprotease-10) and ADAM17. We also exposed cultured cells to tobacco smoke and assessed ADAM10 and ADAM17 expression and release on MVs. Immunohistochemistry showed abundant ADAM10 and ADAM17 protein in the ILT and underlying aneurysmal aorta. Domain-specific antibodies indicated both transmembrane and shed ADAM17. Importantly, ADAM10 and ADAM 17 in the abluminal ILT were enzymatically active. Electron microscopy of abluminal ILT and aortic wall showed MVs with ADAM10 and ADAM17. By flow cytometry, ADAM-positive microvesicles from abluminal ILT carried the neutrophil marker CD66, but not the platelet marker CD61. Cultured HL60 neutrophils exposed to tobacco smoke extract showed increased ADAM10 and ADAM17 content, cleavage of these molecules into active forms, and release of MVs carrying mature ADAM10 and detectable ADAM17. In conclusion, our results implicate persistent, enzymatically active ADAMs on MVs in the abluminal ILT, adjacent to the aneurysmal wall. The production of ADAM10- and ADAM17-positive MVs from smoke-exposed neutrophils provides a novel molecular mechanism for the vastly accelerated risk of AAA in smokers.