A disintegrin and metalloproteinase 10 (ADAM10) plays a major role in the ectodomain shedding of important surface molecules with physiological and pathological relevance including the amyloid precursor protein (APP), the cellular prion protein, and different cadherins. Despite its therapeutic potential, there is still a considerable lack of knowledge how this protease is regulated. We have previously identified tetraspanin15 (Tspan15) as a member of the TspanC8 family to specifically associate with ADAM10. Cell-based overexpression experiments revealed that this binding affected the maturation process and surface expression of the protease. Our current study shows that Tspan15 is abundantly expressed in mouse brain, where it specifically interacts with endogenous ADAM10. Tspan15 knockout mice did not reveal an overt phenotype but showed a pronounced decrease of the active and mature form of ADAM10, an effect which augmented with aging. The decreased expression of active ADAM10 correlated with an age-dependent reduced shedding of neuronal (N)-cadherin and the cellular prion protein. APP α-secretase cleavage and the expression of Notch-dependent genes were not affected by the loss of Tspan15, which is consistent with the hypothesis that different TspanC8s cause ADAM10 to preferentially cleave particular substrates. Analyzing spine morphology revealed no obvious differences between Tspan15 knockout and wild-type mice. However, Tspan15 expression was elevated in brains of an Alzheimer's disease mouse model and of patients, suggesting that upregulation of Tspan15 expression reflects a cellular response in a disease state. In conclusion, our data show that Tspan15 and most likely also other members of the TspanC8 family are central modulators of ADAM10-mediated ectodomain shedding in vivo.

• MeSH
• Alzheimerova nemoc genetika   metabolismus   MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• lidé MeSH
• mozek metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• neurony metabolismus   MeSH
• protein ADAM10 genetika   metabolismus   MeSH
• regulace genové exprese * MeSH
• stanovení celkové genové exprese metody   MeSH
• synapse metabolismus   MeSH
• tetraspaniny genetika   metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

UNLABELLED: A Disintegrin And Metalloprotease (ADAM) 10 exerts essential roles during organ development and tissue integrity in different organs, mainly through activation of the Notch pathway. However, only little is known about its implication in liver tissue physiology. Here we show that in contrast to its role in other tissues, ADAM10 is dispensable for the Notch2-dependent biliary tree formation. However, we demonstrate that expression of bile acid transporters is dependent on ADAM10. Consequently, mice deficient for Adam10 in hepatocytes, cholangiocytes and liver progenitor cells develop spontaneous hepatocyte necrosis and concomitant liver fibrosis. We furthermore observed a strongly augmented ductular reaction in 15-week old ADAM10(Δhep/Δch) mice and demonstrate that c-Met dependent liver progenitor cell activation is enhanced. Additionally, liver progenitor cells are primed to hepatocyte differentiation in the absence of ADAM10. These findings show that ADAM10 is a novel central node controlling liver tissue homeostasis. HIGHLIGHTS: Loss of ADAM10 in murine liver results in hepatocyte necrosis and concomitant liver fibrosis. ADAM10 directly regulates expression of bile acid transporters but is dispensable for Notch2-dependent formation of the biliary system. Activation of liver progenitor cells is enhanced through increased c-Met signalling, in the absence of ADAM10. Differentiation of liver progenitor cells to hepatocytes is augmented in the absence of ADAM10.

• MeSH
• buněčná diferenciace fyziologie   MeSH
• down regulace MeSH
• hepatocyty metabolismus   patologie   MeSH
• homeostáza MeSH
• játra cytologie   metabolismus   patologie   MeSH
• membránové glykoproteiny metabolismus   MeSH
• membránové proteiny nedostatek   genetika   metabolismus   MeSH
• myši knockoutované MeSH
• myši transgenní MeSH
• myši MeSH
• nekróza MeSH
• proliferace buněk fyziologie   MeSH
• protein ADAM10 nedostatek   genetika   metabolismus   MeSH
• receptor Notch2 metabolismus   MeSH
• sekretasy nedostatek   genetika   metabolismus   MeSH
• signální transdukce MeSH
• transportní proteiny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

ADAM10 and ADAM17 are proteases that affect multiple signalling pathways by releasing molecules from the cell surface. As their substrate specificities partially overlaps, we investigated their concurrent role in liver regeneration and fibrosis, using three liver-specific deficient mouse lines: ADAM10- and ADAM17-deficient lines, and a line deficient for both proteases. In the model of partial hepatectomy, double deficient mice exhibited decreased AKT phosphorylation, decreased release of EGFR activating factors and lower shedding of HGF receptor c-Met. Thus, simultaneous ablation of ADAM10 and ADAM17 resulted in inhibited EGFR signalling, while HGF/c-Met signalling pathway was enhanced. In contrast, antagonistic effects of ADAM10 and ADAM17 were observed in the model of chronic CCl4 intoxication. While ADAM10-deficient mice develop more severe fibrosis manifested by high ALT, AST, ALP and higher collagen deposition, combined deficiency of ADAM10 and ADAM17 surprisingly results in comparable degree of liver damage as in control littermates. Therefore, ADAM17 deficiency is not protective in fibrosis development per se, but can ameliorate the damaging effect of ADAM10 deficiency on liver fibrosis development. Furthermore, we show that while ablation of ADAM17 resulted in decreased shedding of TNF RI, ADAM10 deficiency leads to increased levels of soluble TNF RI in serum. In conclusion, hepatocyte-derived ADAM10 and ADAM17 are important regulators of growth receptor signalling and TNF RI release, and pathological roles of these proteases are dependent on the cellular context.

• MeSH
• fibróza metabolismus   MeSH
• játra * metabolismus   patologie   MeSH
• kultivované buňky MeSH
• membránové proteiny fyziologie   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nemoci jater * metabolismus   patologie   MeSH
• primární buněčná kultura MeSH
• protein ADAM10 fyziologie   MeSH
• protein ADAM17 fyziologie   MeSH
• regenerace jater * MeSH
• sekretasy fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Despite existing knowledge about the role of the A Disintegrin and Metalloproteinase 10 (ADAM10) as the α-secretase involved in the non-amyloidogenic processing of the amyloid precursor protein (APP) and Notch signalling we have only limited information about its regulation. In this study, we have identified ADAM10 interactors using a split ubiquitin yeast two hybrid approach. Tetraspanin 3 (Tspan3), which is highly expressed in the murine brain and elevated in brains of Alzheimer´s disease (AD) patients, was identified and confirmed to bind ADAM10 by co-immunoprecipitation experiments in mammalian cells in complex with APP and the γ-secretase protease presenilin. Tspan3 expression increased the cell surface levels of its interacting partners and was mainly localized in early and late endosomes. In contrast to the previously described ADAM10-binding tetraspanins, Tspan3 did not affect the endoplasmic reticulum to plasma membrane transport of ADAM10. Heterologous Tspan3 expression significantly increased the appearance of carboxy-terminal cleavage products of ADAM10 and APP, whereas N-cadherin ectodomain shedding appeared unaffected. Inhibiting the endocytosis of Tspan3 by mutating a critical cytoplasmic tyrosine-based internalization motif led to increased surface expression of APP and ADAM10. After its downregulation in neuroblastoma cells and in brains of Tspan3-deficient mice, ADAM10 and APP levels appeared unaltered possibly due to a compensatory increase in the expression of Tspans 5 and 7, respectively. In conclusion, our data suggest that Tspan3 acts in concert with other tetraspanins as a stabilizing factor of active ADAM10, APP and the γ-secretase complex at the plasma membrane and within the endocytic pathway.

• MeSH
• amyloidový prekurzorový protein beta genetika   metabolismus   MeSH
• buněčná membrána metabolismus   MeSH
• endocytóza MeSH
• endozomy chemie   metabolismus   MeSH
• HEK293 buňky MeSH
• kadheriny genetika   metabolismus   MeSH
• lidé MeSH
• membránové proteiny genetika   metabolismus   MeSH
• mozek - chemie MeSH
• mozek metabolismus   MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• neurony cytologie   metabolismus   MeSH
• preseniliny genetika   metabolismus   MeSH
• protein ADAM10 genetika   metabolismus   MeSH
• proteiny nervové tkáně genetika   metabolismus   MeSH
• receptory Notch genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• sekretasy genetika   metabolismus   MeSH
• signální transdukce MeSH
• techniky dvojhybridového systému MeSH
• tetraspaniny genetika   metabolismus   MeSH
• transport proteinů MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The signalling pathway elicited by hepatocyte growth factor (HGF) and its receptor c-Met is indispensable for liver development and regeneration. It has been described that c-Met is released from the cell surface by a disintegrin and metalloprotease 10 (ADAM10) resulting in a soluble c-Met form known as sMet. Using the human hepatocellular HepG2 and hepatic stellate cell LX2 lines we show that sMet is released from the cell surface of liver cells by both ADAM17 and ADAM10, with ADAM17 appearing to be the major proteinase. Moreover, using a mouse model of 3,5-diethoxycarbonyl- 1,4-dihydroxycollidine (DDC)-induced hepatobiliary obstruction we show that serum levels of sMet correlate well with the liver damage state and consecutive regeneration as well as with established markers of liver damage such as alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin. However, sMet exhibited remarkably better correlation with liver damage and inflammation than did serum tumour necrosis factor α (TNF-α), whose shedding is also mediated by ADAM proteolytic activity. Our results indicate that the proteolytic activity of ADAM10/17 is essential for regulating HGF/c-Met signalling during acute liver damage and following regeneration and that the differential serum levels of sMet together with expression of c-Met/HGF might be a useful indicator not only for damage, but also for ongoing liver regeneration.

• MeSH
• alanintransaminasa krev   MeSH
• aspartátaminotransferasy krev   MeSH
• bilirubin metabolismus   MeSH
• biologické markery metabolismus   MeSH
• buňky Hep G2 MeSH
• hepatocyty metabolismus   patologie   MeSH
• jaterní hvězdicovité buňky metabolismus   patologie   MeSH
• játra metabolismus   patologie   MeSH
• lidé MeSH
• membránové proteiny metabolismus   MeSH
• messenger RNA genetika   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nemoci jater krev   metabolismus   patologie   MeSH
• proteiny ADAM metabolismus   MeSH
• protoonkogenní proteiny c-met krev   metabolismus   MeSH
• rozpustnost MeSH
• sekretasy metabolismus   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Rhomboids are intramembrane serine proteases conserved in all kingdoms of life. They regulate epidermal growth factor receptor signalling in Drosophila by releasing signalling ligands from their transmembrane tethers. Their functions in mammals are poorly understood, in part because of the lack of endogenous substrates identified thus far. We used a quantitative proteomics approach to investigate the substrate repertoire of rhomboid protease RHBDL2 in human cells. We reveal a range of novel substrates that are specifically cleaved by RHBDL2, including the interleukin-6 receptor (IL6R), cell surface protease inhibitor Spint-1, the collagen receptor tyrosine kinase DDR1, N-Cadherin, CLCP1/DCBLD2, KIRREL, BCAM and others. We further demonstrate that these substrates can be shed by endogenously expressed RHBDL2 and that a subset of them is resistant to shedding by cell surface metalloproteases. The expression profiles and identity of the substrates implicate RHBDL2 in physiological or pathological processes affecting epithelial homeostasis.

• MeSH
• epitel metabolismus   MeSH
• epitelové buňky metabolismus   MeSH
• homeostáza * MeSH
• interakční proteinové domény a motivy MeSH
• lidé MeSH
• membránové proteiny metabolismus   MeSH
• protein ADAM10 metabolismus   MeSH
• protein ADAM17 metabolismus   MeSH
• proteolýza MeSH
• proteom * MeSH
• proteomika * metody   MeSH
• sekvence aminokyselin MeSH
• serinové proteasy genetika   metabolismus   MeSH
• substrátová specifita MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Uptake of bacteria by phagocytes is a crucial step in innate immune defence. Members of the disintegrin and metalloproteinase (ADAM) family critically control the immune response by limited proteolysis of surface expressed mediator molecules. Here, we investigated the significance of ADAM17 and its regulatory adapter molecule iRhom2 for bacterial uptake by phagocytes. Inhibition of metalloproteinase activity led to increased phagocytosis of pHrodo labelled Gram-negative and -positive bacteria (E. coli and S. aureus, respectively) by human and murine monocytic cell lines or primary phagocytes. Bone marrow-derived macrophages showed enhanced uptake of heat-inactivated and living E. coli when they lacked either ADAM17 or iRhom2 but not upon ADAM10-deficiency. In monocytic THP-1 cells, corresponding short hairpin RNA (shRNA)-mediated knockdown confirmed that ADAM17, but not ADAM10, promoted phagocytosis of E. coli. The augmented bacterial uptake occurred in a cell autonomous manner and was accompanied by increased release of the chemokine CXCL8, less TNFα release and only minimal changes in the surface expression of the receptors TNFR1, TLR6 and CD36. Inhibition experiments indicated that the enhanced bacterial phagocytosis after ADAM17 knockdown was partially dependent on TNFα-activity but not on CXCL8. This novel role of ADAM17 in bacterial uptake needs to be considered in the development of ADAM17 inhibitors as therapeutics.

• MeSH
• antigeny CD36 genetika   metabolismus   MeSH
• Escherichia coli patogenita   MeSH
• fagocytóza MeSH
• fagocyty metabolismus   mikrobiologie   MeSH
• interleukin-8 metabolismus   MeSH
• intracelulární signální peptidy a proteiny genetika   metabolismus   MeSH
• kultivované buňky MeSH
• lidé MeSH
• myši MeSH
• protein ADAM17 genetika   metabolismus   MeSH
• RAW 264.7 buňky MeSH
• receptory TNF - typ I genetika   metabolismus   MeSH
• Staphylococcus aureus patogenita   MeSH
• THP-1 buňky MeSH
• toll-like receptor 6 genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH