26
|
Sennello JA, Misharin AV, Flozak AS, Berdnikovs S, Cheresh P, Varga J, Kamp DW, Budinger GRS, Gottardi CJ, Lam AP. Lrp5/β-Catenin Signaling Controls Lung Macrophage Differentiation and Inhibits Resolution of Fibrosis. Am J Respir Cell Mol Biol 2017; 56:191-201. [PMID: 27668462 DOI: 10.1165/rcmb.2016-0147oc] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Previous studies established that attenuating Wnt/β-catenin signaling limits lung fibrosis in the bleomycin mouse model of this disease, but the contribution of this pathway to distinct lung cell phenotypes relevant to tissue repair and fibrosis remains incompletely understood. Using microarray analysis, we found that bleomycin-injured lungs from mice that lack the Wnt coreceptor low density lipoprotein receptor-related protein 5 (Lrp5) and exhibit reduced fibrosis showed enrichment for pathways related to extracellular matrix processing, immunity, and lymphocyte proliferation, suggesting the contribution of an immune-matrix remodeling axis relevant to fibrosis. Activation of β-catenin signaling was seen in lung macrophages using the β-catenin reporter mouse, Axin2+/LacZ. Analysis of lung immune cells by flow cytometry after bleomycin administration revealed that Lrp5-/- lungs contained significantly fewer Siglec Flow alveolar macrophages, a cell type previously implicated as positive effectors of fibrosis. Macrophage-specific deletion of β-catenin in CD11ccre;β-cateninflox mice did not prevent development of bleomycin-induced fibrosis but facilitated its resolution by 8 weeks. In a nonresolving model of fibrosis, intratracheal administration of asbestos in Lrp5-/- mice also did not prevent the development of fibrosis but hindered the progression of fibrosis in asbestos-treated Lrp5-/- lungs, phenocopying the findings in bleomycin-treated CD11ccre;β-cateninflox mice. Activation of β-catenin signaling using lithium chloride resulted in worsened fibrosis in wild-type mice, further supporting that the effects of loss of Lrp5 are directly mediated by Wnt/β-catenin signaling. Together, these data suggest that lung myeloid cells are responsive to Lrp5/β-catenin signaling, leading to differentiation of an alveolar macrophage subtype that antagonizes the resolution of lung fibrosis.
Collapse
|
27
|
Serebryannyy LA, Yemelyanov A, Gottardi CJ, de Lanerolle P. Nuclear α-catenin mediates the DNA damage response via β-catenin and nuclear actin. J Cell Sci 2017; 130:1717-1729. [PMID: 28348105 DOI: 10.1242/jcs.199893] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 03/20/2017] [Indexed: 12/29/2022] Open
Abstract
α-Catenin is an F-actin-binding protein widely recognized for its role in cell-cell adhesion. However, a growing body of literature indicates that α-catenin is also a nuclear protein. In this study, we show that α-catenin is able to modulate the sensitivity of cells to DNA damage and toxicity. Furthermore, nuclear α-catenin is actively recruited to sites of DNA damage. This recruitment occurs in a β-catenin-dependent manner and requires nuclear actin polymerization. These findings provide mechanistic insight into the WNT-mediated regulation of the DNA damage response and suggest a novel role for the α-catenin-β-catenin complex in the nucleus.
Collapse
|
28
|
Chiarella SE, Gonzalez-Gonzalez FJ, McQuattie-Pimentel AC, Singer BD, Budinger GS, Schleimer RP, Gottardi CJ. Defining the Cell Type through Which the Asthma-Associated Intercellular Junction Protein Alpha-T-Catenin Drives Asthma Phenotypes in Mice. J Allergy Clin Immunol 2017. [DOI: 10.1016/j.jaci.2016.12.558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
29
|
Serebryannyy LA, Parilla M, Annibale P, Cruz CM, Laster K, Gratton E, Kudryashov D, Kosak ST, Gottardi CJ, de Lanerolle P. Persistent nuclear actin filaments inhibit transcription by RNA polymerase II. J Cell Sci 2016; 129:3412-25. [PMID: 27505898 DOI: 10.1242/jcs.195867] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 07/27/2016] [Indexed: 12/26/2022] Open
Abstract
Actin is abundant in the nucleus and it is clear that nuclear actin has important functions. However, mystery surrounds the absence of classical actin filaments in the nucleus. To address this question, we investigated how polymerizing nuclear actin into persistent nuclear actin filaments affected transcription by RNA polymerase II. Nuclear filaments impaired nuclear actin dynamics by polymerizing and sequestering nuclear actin. Polymerizing actin into stable nuclear filaments disrupted the interaction of actin with RNA polymerase II and correlated with impaired RNA polymerase II localization, dynamics, gene recruitment, and reduced global transcription and cell proliferation. Polymerizing and crosslinking nuclear actin in vitro similarly disrupted the actin-RNA-polymerase-II interaction and inhibited transcription. These data rationalize the general absence of stable actin filaments in mammalian somatic nuclei. They also suggest a dynamic pool of nuclear actin is required for the proper localization and activity of RNA polymerase II.
Collapse
|
30
|
Folmsbee SS, Budinger GRS, Bryce PJ, Gottardi CJ. The cardiomyocyte protein αT-catenin contributes to asthma through regulating pulmonary vein inflammation. J Allergy Clin Immunol 2016; 138:123-129.e2. [PMID: 26947180 PMCID: PMC4931945 DOI: 10.1016/j.jaci.2015.11.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/14/2015] [Accepted: 11/20/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND Recent genome-wide association studies have identified single nucleotide polymorphisms in the gene encoding the protein αT-catenin (CTNNA3) that correlate with both steroid-resistant atopic asthma and asthmatic exacerbations. α-Catenins are important mediators of cell-cell adhesion, and αT-catenin is predominantly expressed in cardiomyocytes. In the lung αT-catenin appears to be exclusively expressed in cardiomyocytes surrounding the pulmonary veins (PVs), but its contribution to atopic asthma remains unknown. OBJECTIVE We sought to understand the role of αT-catenin in asthma pathogenesis. METHODS We used αT-catenin knockout mice and a house dust mite (HDM) extract model of atopic asthma, with assessment by means of forced oscillation, bronchoalveolar lavage, and histologic analysis. RESULTS We found that the genetic loss of αT-catenin in mice largely attenuated HDM-induced airway inflammation and airway hyperresponsiveness to methacholine. Mice lacking αT-catenin that were exposed to HDM extract had reduced PV inflammation, specifically near the large veins surrounded by cardiac cells. The proximity of the airways to PVs correlated with the severity of airway goblet cell metaplasia, suggesting that PVs can influence the inflammatory milieu of adjacent airways. Loss of αT-catenin led to compensatory upregulation of αE-catenin, which itself has a defined anti-inflammatory function. CONCLUSION These data mechanistically support previous clinical and genetic associations between αT-catenin and the development of atopic asthma and suggest that PVs might have an underappreciated role in allergic airway inflammation.
Collapse
|
31
|
Folmsbee SS, Wilcox DR, Tyberghein K, De Bleser P, Tourtellotte WG, van Hengel J, van Roy F, Gottardi CJ. αT-catenin in restricted brain cell types and its potential connection to autism. J Mol Psychiatry 2016; 4:2. [PMID: 27330745 PMCID: PMC4915096 DOI: 10.1186/s40303-016-0017-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/08/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Recent genetic association studies have linked the cadherin-based adherens junction protein alpha-T-catenin (αT-cat, CTNNA3) with the development of autism. Where αT-cat is expressed in the brain, and how its loss could contribute to this disorder, are entirely unknown. METHODS We used the αT-cat knockout mouse to examine the localization of αT-cat in the brain, and we used histology and immunofluorescence analysis to examine the neurobiological consequences of its loss. RESULTS We found that αT-cat comprises the ependymal cell junctions of the ventricles of the brain, and its loss led to compensatory upregulation of αE-cat expression. Notably, αT-cat was not detected within the choroid plexus, which relies on cell junction components common to typical epithelial cells. While αT-cat was not detected in neurons of the cerebral cortex, it was abundantly detected within neuronal structures of the molecular layer of the cerebellum. Although αT-cat loss led to no overt differences in cerebral or cerebellar structure, RNA-sequencing analysis from wild type versus knockout cerebella identified a number of disease-relevant signaling pathways associated with αT-cat loss, such as GABA-A receptor activation. CONCLUSIONS These findings raise the possibility that the genetic associations between αT-cat and autism may be due to ependymal and cerebellar defects, and highlight the potential importance of a seemingly redundant adherens junction component to a neurological disorder.
Collapse
|
32
|
Chen Y, Li Y, Xue J, Gong A, Yu G, Zhou A, Lin K, Zhang S, Zhang N, Gottardi CJ, Huang S. Wnt-induced deubiquitination FoxM1 ensures nucleus β-catenin transactivation. EMBO J 2016; 35:668-84. [PMID: 26912724 DOI: 10.15252/embj.201592810] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 01/19/2016] [Indexed: 11/09/2022] Open
Abstract
A key step of Wnt signaling activation is the recruitment of β-catenin to the Wnt target-gene promoter in the nucleus, but its mechanisms are largely unknown. Here, we identified FoxM1 as a novel target of Wnt signaling, which is essential for β-catenin/TCF4 transactivation. GSK3 phosphorylates FoxM1 on serine 474 which induces FoxM1 ubiquitination mediated by FBXW7. Wnt signaling activation inhibits FoxM1 phosphorylation by GSK3-Axin complex and leads to interaction between FoxM1 and deubiquitinating enzyme USP5, thereby deubiquitination and stabilization of FoxM1. FoxM1 accumulation in the nucleus promotes recruitment of β-catenin to Wnt target-gene promoter and activates the Wnt signaling pathway by protecting the β-catenin/TCF4 complex from ICAT inhibition. Subsequently, the USP5-FoxM1 axis abolishes the inhibitory effect of ICAT and is required for Wnt-mediated tumor cell proliferation. Therefore, Wnt-induced deubiquitination of FoxM1 represents a novel and critical mechanism for controlling canonical Wnt signaling and cell proliferation.
Collapse
|
33
|
Reinke L, Lam AP, Flozak AS, Varga J, Gottardi CJ. Adiponectin inhibits Wnt co-receptor, Lrp6, phosphorylation and β-catenin signaling. Biochem Biophys Res Commun 2016; 470:606-612. [PMID: 26797284 DOI: 10.1016/j.bbrc.2016.01.097] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 01/15/2016] [Indexed: 12/15/2022]
Abstract
Adiponectin is a pleiotropic adipokine implicated in obesity, metabolic syndrome and cardiovascular disease. Recent studies have identified adiponectin as a negative regulator of tissue fibrosis. Wnt/β-catenin signaling has also been implicated in metabolic syndrome and can promote tissue fibrosis, but the extent to which adiponectin cross-regulates Wnt/β-catenin signaling is unknown. Using primary human dermal fibroblasts and recombinant purified proteins, we show that adiponectin can limit β-catenin accumulation and downstream gene activation by inhibiting Lrp6 phosphorylation, a key activation step in canonical Wnt signaling. Inhibition of Wnt3a-mediated Lrp6 phospho-activation is relatively rapid (e.g., by 30 min), and is not dependent on established adiponectin G-protein coupled receptors, AdipoR1 and R2, suggesting a more direct relationship to Lrp6 signaling. In contrast, the ability of adiponectin to limit Wnt-induced and baseline collagen production in fibroblasts requires AdipoR1/R2. These results suggest the possibility that the pleiotropic effects of adiponectin may be mediated through distinct cell surface receptor complexes. Accordingly, we propose that the anti-fibrotic activity of adiponectin may be mediated through AdipoR1/R2 receptors, while the ability of adiponectin to inhibit Lrp6 phospho-activation may be relevant to other recently established roles for Lrp6 signaling in glucose metabolism and metabolic syndrome.
Collapse
|
34
|
Flozak AS, Lam AP, Gottardi CJ. A Simple Method to Assess Abundance of the β-Catenin Signaling Pool in Cells. Methods Mol Biol 2016; 1481:49-60. [PMID: 27590151 DOI: 10.1007/978-1-4939-6393-5_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
β-catenin (CTNNB1) is a dual-function cell-cell adhesion/transcriptional co-activator protein and an essential transducer of canonical Wnt signals. Although a number of established techniques and reagents are available to quantify the nuclear signaling activity of β-catenin (e.g., TCF-dependent reporter assays, nuclear accumulation of β-catenin, and generation of N-terminally hypophosphorylated β-catenin), there are cell-type and context-dependent limitations of these methods. Since the posttranscriptional stabilization of β-catenin outside of the cadherin complex appears universally required for β-catenin signaling, the following method allows for simple assessment of the cadherin-free fraction of β-catenin in cells, using a GST-tagged form of ICAT (Inhibitor of β-Catenin and Tcf) as an affinity matrix. This method is more sensitive and quantitative than immunofluorescence and may be useful in studies that implicate TCF-independent signaling events.
Collapse
|
35
|
Valenti F, Ibetti J, Komiya Y, Baxter M, Lucchese AM, Derstine L, Covaciu C, Rizzo V, Vento R, Russo G, Macaluso M, Cotelli F, Castiglia D, Gottardi CJ, Habas R, Giordano A, Bellipanni G. The increase in maternal expression of axin1 and axin2 contribute to the zebrafish mutant ichabod ventralized phenotype. J Cell Biochem 2015; 116:418-30. [PMID: 25335865 DOI: 10.1002/jcb.24993] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 10/06/2014] [Indexed: 11/11/2022]
Abstract
β-Catenin is a central effector of the Wnt pathway and one of the players in Ca(+)-dependent cell-cell adhesion. While many wnts are present and expressed in vertebrates, only one β-catenin exists in the majority of the organisms. One intriguing exception is zebrafish that carries two genes for β-catenin. The maternal recessive mutation ichabod presents very low levels of β-catenin2 that in turn affects dorsal axis formation, suggesting that β-catenin1 is incapable to compensate for β-catenin2 loss and raising the question of whether these two β-catenins may have differential roles during early axis specification. Here we identify a specific antibody that can discriminate selectively for β-catenin1. By confocal co-immunofluorescent analysis and low concentration gain-of-function experiments, we show that β-catenin1 and 2 behave in similar modes in dorsal axis induction and cellular localization. Surprisingly, we also found that in the ich embryo the mRNAs of the components of β-catenin regulatory pathway, including β-catenin1, are more abundant than in the Wt embryo. Increased levels of β-catenin1 are found at the membrane level but not in the nuclei till high stage. Finally, we present evidence that β-catenin1 cannot revert the ich phenotype because it may be under the control of a GSK3β-independent mechanism that required Axin's RGS domain function.
Collapse
|
36
|
Escobar DJ, Desai R, Ishiyama N, Folmsbee SS, Novak MN, Flozak AS, Daugherty RL, Mo R, Nanavati D, Sarpal R, Leckband D, Ikura M, Tepass U, Gottardi CJ. α-Catenin phosphorylation promotes intercellular adhesion through a dual-kinase mechanism. Development 2015. [DOI: 10.1242/dev.124123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
37
|
Abstract
The arrival of multicellularity in evolution facilitated cell-cell signaling in conjunction with adhesion. As the ectodomains of cadherins interact with each other directly in trans (as well as in cis), spanning the plasma membrane and associating with multiple other entities, cadherins enable the transduction of "outside-in" or "inside-out" signals. We focus this review on signals that originate from the larger family of cadherins that are inwardly directed to the nucleus, and thus have roles in gene control or nuclear structure-function. The nature of cadherin complexes varies considerably depending on the type of cadherin and its context, and we will address some of these variables for classical cadherins versus other family members. Substantial but still fragmentary progress has been made in understanding the signaling mediators used by varied cadherin complexes to coordinate the state of cell-cell adhesion with gene expression. Evidence that cadherin intracellular binding partners also localize to the nucleus is a major point of interest. In some models, catenins show reduced binding to cadherin cytoplasmic tails favoring their engagement in gene control. When bound, cadherins may serve as stoichiometric competitors of nuclear signals. Cadherins also directly or indirectly affect numerous signaling pathways (e.g., Wnt, receptor tyrosine kinase, Hippo, NFκB, and JAK/STAT), enabling cell-cell contacts to touch upon multiple biological outcomes in embryonic development and tissue homeostasis.
Collapse
|
38
|
Escobar DJ, Desai R, Ishiyama N, Folmsbee SS, Novak MN, Flozak AS, Daugherty RL, Mo R, Nanavati D, Sarpal R, Leckband D, Ikura M, Tepass U, Gottardi CJ. α-Catenin phosphorylation promotes intercellular adhesion through a dual-kinase mechanism. J Cell Sci 2015; 128:1150-65. [PMID: 25653389 DOI: 10.1242/jcs.163824] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The cadherin-catenin adhesion complex is a key contributor to epithelial tissue stability and dynamic cell movements during development and tissue renewal. How this complex is regulated to accomplish these functions is not fully understood. We identified several phosphorylation sites in mammalian αE-catenin (also known as catenin α-1) and Drosophila α-Catenin within a flexible linker located between the middle (M)-region and the carboxy-terminal actin-binding domain. We show that this phospho-linker (P-linker) is the main phosphorylated region of α-catenin in cells and is sequentially modified at casein kinase 2 and 1 consensus sites. In Drosophila, the P-linker is required for normal α-catenin function during development and collective cell migration, although no obvious defects were found in cadherin-catenin complex assembly or adherens junction formation. In mammalian cells, non-phosphorylatable forms of α-catenin showed defects in intercellular adhesion using a mechanical dispersion assay. Epithelial sheets expressing phosphomimetic forms of α-catenin showed faster and more coordinated migrations after scratch wounding. These findings suggest that phosphorylation and dephosphorylation of the α-catenin P-linker are required for normal cadherin-catenin complex function in Drosophila and mammalian cells.
Collapse
|
39
|
Folmsbee SS, Gottardi CJ. The Cardiac Protein Alpha-T-Catenin Contributes to the Pathogenesis of Occupational Asthma. J Allergy Clin Immunol 2015. [DOI: 10.1016/j.jaci.2014.12.1181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
40
|
Folmsbee SS, Morales-Nebreda L, Van Hengel J, Tyberghein K, Van Roy F, Budinger GRS, Bryce PJ, Gottardi CJ. The cardiac protein αT-catenin contributes to chemical-induced asthma. Am J Physiol Lung Cell Mol Physiol 2014; 308:L253-8. [PMID: 25480337 DOI: 10.1152/ajplung.00331.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Ten to 25% of adult asthma is occupational induced, a subtype caused by exposure to workplace chemicals. A recent genomewide association study identified single-nucleotide polymorphisms in the cardiac protein αT-catenin (αT-cat) that correlated with the incidence and severity of toluene diisocyanate (TDI) occupational asthma. αT-cat is a critical mediator of cell-cell adhesion and is predominantly expressed in cardiomyocytes, but its connection to asthma remains unknown. Therefore, we sought to determine the primary αT-cat-expressing cell type in the lung and its contribution to lung physiology in a murine model of TDI asthma. We show that αT-cat is expressed in lung within the cardiac sheath of pulmonary veins. Mechanically ventilated αT-cat knockout (KO) mice exhibit a significantly increased pressure-volume curve area compared with wild-type (WT) mice, suggesting that αT-cat loss affects lung hysteresis. Using a murine model of TDI asthma, we find that αT-cat KO mice show increased airway hyperresponsiveness to methacholine compared with WT mice. Bronchoalveolar lavage reveals only a mild macrophage-dominant inflammation that is not significantly different between WT and KO mice. These data suggest that αT-cat may contribute to asthma through a mechanism independent of inflammation and related to heart and pulmonary vein dysfunction.
Collapse
|
41
|
Lam AP, Herazo-Maya JD, Sennello JA, Flozak AS, Russell S, Mutlu GM, Budinger GRS, DasGupta R, Varga J, Kaminski N, Gottardi CJ. Wnt coreceptor Lrp5 is a driver of idiopathic pulmonary fibrosis. Am J Respir Crit Care Med 2014; 190:185-95. [PMID: 24921217 DOI: 10.1164/rccm.201401-0079oc] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Wnt/β-catenin signaling has been implicated in lung fibrosis, but how this occurs and whether expression changes in Wnt pathway components predict disease progression is unknown. OBJECTIVES To determine whether the Wnt coreceptor Lrp5 drives pulmonary fibrosis in mice and is predictive of disease severity in humans. METHODS We examined mice with impaired Wnt signaling caused by loss of the Wnt coreceptor Lrp5 in models of lung fibrosis induced by bleomycin or an adenovirus encoding an active form of transforming growth factor (TGF)-β. We also analyzed gene expression in peripheral blood mononuclear cells (PBMC) from patients with idiopathic pulmonary fibrosis (IPF). MEASUREMENTS AND MAIN RESULTS In patients with IPF, analysis of peripheral blood mononuclear cells revealed that elevation of positive regulators, Lrp5 and 6, was independently associated with disease progression. LRP5 was also associated with disease severity at presentation in an additional cohort of patients with IPF. Lrp5 null mice were protected against bleomycin-induced pulmonary fibrosis, an effect that was phenocopied by direct inhibition of β-catenin signaling by the small molecular inhibitor of β-catenin responsive transcription. Transplantation of Lrp5 null bone marrow cells into wild-type mice did not limit fibrosis. Instead, Lrp5 loss was associated with reduced TGF-β production by alveolar type 2 cells and leukocytes. Consistent with a role of Lrp5 in the activation of TGF-β, Lrp5 null mice were not protected against lung fibrosis induced by TGF-β. CONCLUSIONS We show that the Wnt coreceptor, Lrp5, is a genetic driver of lung fibrosis in mice and a marker of disease progression and severity in humans with IPF. Evidence that TGF-β signaling can override a loss in Lrp5 has implications for patient selection and timing of Wnt pathway inhibitors in lung fibrosis.
Collapse
|
42
|
McEwen AE, Maher MT, Mo R, Gottardi CJ. E-cadherin phosphorylation occurs during its biosynthesis to promote its cell surface stability and adhesion. Mol Biol Cell 2014; 25:2365-74. [PMID: 24966173 PMCID: PMC4142610 DOI: 10.1091/mbc.e14-01-0690] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
E-cadherin is highly phosphorylated within its β-catenin-binding region, and this phosphorylation increases its affinity for β-catenin in vitro. However, the identification of key serines responsible for most cadherin phosphorylation and the adhesive consequences of modification at such serines have remained unknown. In this study, we show that as few as three serines in the β-catenin-binding domain of E-cadherin are responsible for most radioactive phosphate incorporation. These serines are required for binding to β-catenin and the mutual stability of both E-cadherin and β-catenin. Cells expressing a phosphodeficient (3S>A) E-cadherin exhibit minimal cell-cell adhesion due to enhanced endocytosis and degradation through a lysosomal compartment. Conversely, negative charge substitution at these serines (3S>D) antagonizes cadherin endocytosis and restores wild-type levels of adhesion. The cadherin kinase is membrane proximal and modifies the cadherin before it reaches the cell surface. Together these data suggest that E-cadherin phosphorylation is largely constitutive and integral to cadherin-catenin complex formation, surface stability, and function.
Collapse
|
43
|
Barry AK, Tabdili H, Muhamed I, Wu J, Shashikanth N, Gomez GA, Yap AS, Gottardi CJ, de Rooij J, Wang N, Leckband DE. α-Catenin cytomechanics – role in cadherin-dependent adhesion and mechanotransduction. Development 2014. [DOI: 10.1242/dev.111419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
44
|
Barry AK, Tabdili H, Muhamed I, Wu J, Shashikanth N, Gomez GA, Yap AS, Gottardi CJ, de Rooij J, Wang N, Leckband DE. α-catenin cytomechanics--role in cadherin-dependent adhesion and mechanotransduction. J Cell Sci 2014; 127:1779-91. [PMID: 24522187 DOI: 10.1242/jcs.139014] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The findings presented here demonstrate the role of α-catenin in cadherin-based adhesion and mechanotransduction in different mechanical contexts. Bead-twisting measurements in conjunction with imaging, and the use of different cell lines and α-catenin mutants reveal that the acute local mechanical manipulation of cadherin bonds triggers vinculin and actin recruitment to cadherin adhesions in an actin- and α-catenin-dependent manner. The modest effect of α-catenin on the two-dimensional binding affinities of cell surface cadherins further suggests that force-activated adhesion strengthening is due to enhanced cadherin-cytoskeletal interactions rather than to α-catenin-dependent affinity modulation. Complementary investigations of cadherin-based rigidity sensing also suggest that, although α-catenin alters traction force generation, it is not the sole regulator of cell contractility on compliant cadherin-coated substrata.
Collapse
|
45
|
|
46
|
Gottardi CJ, Königshoff M. Considerations for targeting β-catenin signaling in fibrosis. Am J Respir Crit Care Med 2013; 187:566-8. [PMID: 23504360 DOI: 10.1164/rccm.201301-0144ed] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
|
47
|
Hamanaka RB, Glasauer A, Hoover P, Yang S, Blatt H, Mullen AR, Getsios S, Gottardi CJ, DeBerardinis RJ, Lavker RM, Chandel NS. Mitochondrial reactive oxygen species promote epidermal differentiation and hair follicle development. Sci Signal 2013; 6:ra8. [PMID: 23386745 DOI: 10.1126/scisignal.2003638] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Proper regulation of keratinocyte differentiation within the epidermis and follicular epithelium is essential for maintenance of epidermal barrier function and hair growth. The signaling intermediates that regulate the morphological and genetic changes associated with epidermal and follicular differentiation remain poorly understood. We tested the hypothesis that reactive oxygen species (ROS) generated by mitochondria are an important regulator of epidermal differentiation by generating mice with a keratinocyte-specific deficiency in mitochondrial transcription factor A (TFAM), which is required for the transcription of mitochondrial genes encoding electron transport chain subunits. Ablation of TFAM in keratinocytes impaired epidermal differentiation and hair follicle growth and resulted in death 2 weeks after birth. TFAM-deficient keratinocytes failed to generate mitochondria-derived ROS, a deficiency that prevented the transmission of Notch and β-catenin signals essential for epidermal differentiation and hair follicle development, respectively. In vitro keratinocyte differentiation was inhibited in the presence of antioxidants, and the decreased differentiation marker abundance in TFAM-deficient keratinocytes was partly rescued by application of exogenous hydrogen peroxide. These findings indicate that mitochondria-generated ROS are critical mediators of cellular differentiation and tissue morphogenesis.
Collapse
|
48
|
Wei J, Fang F, Lam AP, Sargent JL, Hamburg E, Hinchcliff ME, Gottardi CJ, Atit R, Whitfield ML, Varga J. Wnt/β-catenin signaling is hyperactivated in systemic sclerosis and induces Smad-dependent fibrotic responses in mesenchymal cells. ARTHRITIS AND RHEUMATISM 2012; 64:2734-45. [PMID: 22328118 PMCID: PMC3553791 DOI: 10.1002/art.34424] [Citation(s) in RCA: 180] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Fibrosis in human diseases and animal models is associated with aberrant Wnt/β-catenin pathway activation. The aim of this study was to characterize the regulation, activity, mechanism of action, and significance of Wnt/β-catenin signaling in the context of systemic sclerosis (SSc). METHODS The expression of Wnt signaling pathway components in SSc skin biopsy specimens was analyzed. The regulation of profibrotic responses by canonical Wnt/β-catenin was examined in explanted human mesenchymal cells. Fibrotic responses were studied using proliferation, migration, and gel contraction assays. The cell fate specification of subcutaneous preadipocytes by canonical Wnt signaling was evaluated. RESULTS Analysis of published genome-wide expression data revealed elevated expression of the Wnt receptor FZD2 and the Wnt target LEF1 and decreased expression of Wnt antagonists DKK2 and WIF1 in skin biopsy specimens from subsets of patients with diffuse cutaneous SSc compared to the other distinct subsets. Immunohistochemical analysis showed increased nuclear β-catenin expression in these biopsy specimens. In vitro, Wnt-3a induced β-catenin activation, stimulated fibroblast proliferation and migration, collagen gel contraction, and myofibroblast differentiation, and enhanced profibrotic gene expression. Genetic and pharmacologic approaches were used to demonstrate that these profibrotic responses involved autocrine transforming growth factor β signaling via Smads. In contrast, in explanted subcutaneous preadipocytes, Wnt-3a repressed adipogenesis and promoted myofibroblast differentiation. CONCLUSION Canonical Wnt signaling was hyperactivated in SSc skin biopsy specimens. In explanted mesenchymal cells, Wnt-3a stimulated fibrogenic responses while suppressing adipogenesis. Taken together, these results indicate that Wnts have potent profibrotic effects, and that canonical Wnt signaling plays an important role in the pathogenesis of fibrosis and lipoatrophy in SSc.
Collapse
|
49
|
Jain M, Lam A, Gottardi CJ. Tissue-specific knockout/knockdown of type 2 TGF-β receptor and protection against bleomycin injury/fibrosis. Am J Respir Crit Care Med 2011; 184:983; author reply 983-4. [PMID: 22003151 DOI: 10.1164/ajrccm.184.8.983a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
50
|
Jain M, Lam A, Gottardi CJ. Tissue-Specific Knockout/Knockdown of Type 2 TGF-β Receptor and Protection against Bleomycin Injury/Fibrosis. Am J Respir Crit Care Med 2011. [DOI: 10.1164/ajrccm.184.8.983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|