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Senetta R, Stella G, Pozzi E, Sturli N, Massi D, Cassoni P. Caveolin-1 as a promoter of tumour spreading: when, how, where and why. J Cell Mol Med 2013; 17:325-36. [PMID: 23521716 PMCID: PMC3823014 DOI: 10.1111/jcmm.12030] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/15/2013] [Indexed: 11/29/2022] Open
Abstract
Caveolae are non-clathrin invaginations of the plasma membrane in most cell types; they are involved in signalling functions and molecule trafficking, thus modulating several biological functions, including cell growth, apoptosis and angiogenesis. The major structural protein in caveolae is caveolin-1, which is known to act as a key regulator in cancer onset and progression through its role as a tumour suppressor. Caveolin-1 can also promote cell proliferation, survival and metastasis as well as chemo- and radioresistance. Here, we discuss recent findings and novel concepts that support a role for caveolin-1 in cancer development and its distant spreading. We also address the potential application of caveolin-1 in tumour therapy and diagnosis.
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Affiliation(s)
- Rebecca Senetta
- Department of Medical Sciences, University of Turin, Turin, Italy
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Caveolin-1 up-regulates integrin α2,6-sialylation to promote integrin α5β1-dependent hepatocarcinoma cell adhesion. FEBS Lett 2013; 587:782-7. [PMID: 23416306 DOI: 10.1016/j.febslet.2013.02.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 02/01/2013] [Accepted: 02/03/2013] [Indexed: 11/20/2022]
Abstract
The alterations of integrin glycosylation play a crucial role in tumor metastasis. Our previous studies indicated that caveolin-1 promoted the expression of the key α2,6-sialytransferase ST6Gal-I and fibronectin-mediated adhesion of mouse hepatocarcinoma cell. Herein, we investigated the role of α2,6-sialylated α5-integrin in the adhesion of mouse hepatocarcinoma H22 cell. We demonstrated that caveolin-1 up-regulated cell surface α2,6-linked sialic acid via stimulating ST6Gal-I transcription. Cell surface α2,6-sialylation was required for integrin α5β1-dependent cell adhesion to fibronectin, and an increase in α2,6-linked sialic acid on α5-subunit facilitated fibronectin-mediated focal adhesion kinase phosphorylations, suggesting that α2,6-sialylated α5-subunit promoted integrin α5β1-dependent cell adhesion.
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Yamamoto K, Ando J. Endothelial cell and model membranes respond to shear stress by rapidly decreasing the order of their lipid phases. J Cell Sci 2013; 126:1227-34. [PMID: 23378020 DOI: 10.1242/jcs.119628] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Endothelial cells (ECs) sense shear stress and transduce blood flow information into functional responses that play important roles in vascular homeostasis and pathophysiology. A unique feature of shear-stress-sensing is the involvement of many different types of membrane-bound molecules, including receptors, ion channels and adhesion proteins, but the mechanisms remain unknown. Because cell membrane properties affect the activities of membrane-bound proteins, shear stress might activate various membrane-bound molecules by altering the physical properties of EC membranes. To determine how shear stress influences the cell membrane, cultured human pulmonary artery ECs were exposed to shear stress and examined for changes in membrane lipid order and fluidity by Laurdan two-photon imaging and FRAP measurements. Upon shear stress stimulation, the lipid order of EC membranes rapidly decreased in an intensity-dependent manner, and caveolar membrane domains changed from the liquid-ordered state to the liquid-disordered state. Notably, a similar decrease in lipid order occurred when the artificial membranes of giant unilamellar vesicles were exposed to shear stress, suggesting that this is a physical phenomenon. Membrane fluidity increased over the entire EC membranes in response to shear stress. Addition of cholesterol to ECs abolished the effects of shear stress on membrane lipid order and fluidity and markedly suppressed ATP release, which is a well-known EC response to shear stress and is involved in shear-stress Ca(2+) signaling. These findings indicate that EC membranes directly respond to shear stress by rapidly decreasing their lipid phase order and increasing their fluidity; these changes could be linked to shear-stress-sensing and response mechanisms.
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Affiliation(s)
- Kimiko Yamamoto
- Laboratory of System Physiology, Department of Biomedical Engineering, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan.
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Strategies for anti-fibrotic therapies. Biochim Biophys Acta Mol Basis Dis 2012; 1832:1088-103. [PMID: 23266403 DOI: 10.1016/j.bbadis.2012.12.007] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 12/07/2012] [Accepted: 12/08/2012] [Indexed: 02/07/2023]
Abstract
The fibrotic diseases encompass a wide spectrum of entities including such multisystemic diseases as systemic sclerosis, nephrogenic systemic fibrosis and sclerodermatous graft versus host disease, as well as organ-specific disorders such as pulmonary, liver, and kidney fibrosis. Collectively, given the wide variety of affected organs, the chronic nature of the fibrotic processes, and the large number of individuals suffering their devastating effects, these diseases pose one of the most serious health problems in current medicine and a serious economic burden to society. Despite these considerations there is currently no accepted effective treatment. However, remarkable progress has been achieved in the elucidation of their pathogenesis including the identification of the critical role of myofibroblasts and the determination of molecular mechanisms that result in the transcriptional activation of the genes responsible for the fibrotic process. Here we review the origin of the myofibroblast and discuss the crucial regulatory pathways involving multiple growth factors and cytokines that participate in the pathogenesis of the fibrotic process. Potentially effective therapeutic strategies based upon this new information are considered in detail and the major challenges that remain and their possible solutions are presented. It is expected that translational efforts devoted to convert this new knowledge into novel and effective anti-fibrotic drugs will be forthcoming in the near future. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.
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Li Z, Wermuth PJ, Benn BS, Lisanti MP, Jimenez SA. Caveolin-1 deficiency induces spontaneous endothelial-to-mesenchymal transition in murine pulmonary endothelial cells in vitro. THE AMERICAN JOURNAL OF PATHOLOGY 2012. [PMID: 23195429 DOI: 10.1016/j.ajpath.2012.10.022] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It was previously demonstrated that transforming growth factor β (TGF-β) induces endothelial-to-mesenchymal transition (EndoMT) in murine lung endothelial cells (ECs) in vitro. Owing to the important role of caveolin-1 (CAV1) in TGF-β receptor internalization and TGF-β signaling, the participation of CAV1 in the induction of EndoMT in murine lung ECs was investigated. Pulmonary ECs were isolated from wild-type and Cav1 knockout mice using immunomagnetic methods with sequential anti-CD31 and anti-CD102 antibody selection followed by in vitro culture and treatment with TGF-β1. EndoMT was assessed by semiquantitative RT-PCR for Acta2, Col1a1, Snai1, and Snai2; by immunofluorescence for α-smooth muscle actin; and by Western blot analysis for α-smooth muscle actin, SNAIL1, SNAIL2, and the α2 chain of type I collagen. The same studies were performed in Cav1(-/-) pulmonary ECs after restoration of functional CAV1 domains using a cell-permeable CAV1 scaffolding domain peptide. Pulmonary ECs from Cav1 knockout mice displayed high levels of spontaneous Acta2, Col1A, Snai1, and Snai2 expression, which increased after TGF-β treatment. Spontaneous and TGF-β1-stimulated EndoMT were abrogated by the restoration of functional CAV1 domains using a cell-permeable peptide. The findings suggest that CAV1 regulation of EndoMT may play a role in the development of fibroproliferative vasculopathies.
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Affiliation(s)
- Zhaodong Li
- Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Hartman WR, Smelter DF, Sathish V, Karass M, Kim S, Aravamudan B, Thompson MA, Amrani Y, Pandya HC, Martin RJ, Prakash YS, Pabelick CM. Oxygen dose responsiveness of human fetal airway smooth muscle cells. Am J Physiol Lung Cell Mol Physiol 2012; 303:L711-9. [PMID: 22923637 DOI: 10.1152/ajplung.00037.2012] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Maintenance of blood oxygen saturation dictates supplemental oxygen administration to premature infants, but hyperoxia predisposes survivors to respiratory diseases such as asthma. Although much research has focused on oxygen effects on alveoli in the setting of bronchopulmonary dysplasia, the mechanisms by which oxygen affects airway structure or function relevant to asthma are still under investigation. We used isolated human fetal airway smooth muscle (fASM) cells from 18-20 postconceptual age lungs (canalicular stage) to examine oxygen effects on intracellular Ca(2+) ([Ca(2+)](i)) and cellular proliferation. fASM cells expressed substantial smooth muscle actin and myosin and several Ca(2+) regulatory proteins but not fibroblast or epithelial markers, profiles qualitatively comparable to adult human ASM. Fluorescence Ca(2+) imaging showed robust [Ca(2+)](i) responses to 1 μM acetylcholine (ACh) and 10 μM histamine (albeit smaller and slower than adult ASM), partly sensitive to zero extracellular Ca(2+). Compared with adult, fASM showed greater baseline proliferation. Based on this validation, we assessed fASM responses to 10% hypoxia through 90% hyperoxia and found enhanced proliferation at <60% oxygen but increased apoptosis at >60%, effects accompanied by appropriate changes in proliferative vs. apoptotic markers and enhanced mitochondrial fission at >60% oxygen. [Ca(2+)](i) responses to ACh were enhanced for <60% but blunted at >60% oxygen. These results suggest that hyperoxia has dose-dependent effects on structure and function of developing ASM, which could have consequences for airway diseases of childhood. Thus detrimental effects on ASM should be an additional consideration in assessing risks of supplemental oxygen in prematurity.
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Du X, Qian X, Papageorge A, Schetter AJ, Vass WC, Liu X, Braverman R, Robles AI, Lowy DR. Functional interaction of tumor suppressor DLC1 and caveolin-1 in cancer cells. Cancer Res 2012; 72:4405-16. [PMID: 22693251 DOI: 10.1158/0008-5472.can-12-0777] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Deleted in liver cancer 1 (DLC1), a tumor suppressor gene frequently inactivated in non-small cell lung cancer (NSCLC) and other malignancies, encodes a multidomain protein with a RhoGTPase-activating (RhoGAP) domain and a StAR-related lipid transfer (START) domain. However, no interacting macromolecule has been mapped to the DLC1 START domain. Caveolin-1 (CAV-1) functions as a tumor suppressor in most contexts and forms a complex with DLC1. Here, we have mapped the region of DLC1 required for interaction with CAV-1 to the DLC1 START domain. Mutation of the DLC1 START domain disrupted the interaction and colocalization with CAV-1. Moreover, DLC1 with a START domain mutation failed to suppress neoplastic growth, although it negatively regulated active Rho. CAV-1 and DLC1 expression levels were correlated in two public datasets of NSCLC lines and in two independent publicly available mRNA expression datasets of NSCLC tumors. Clinically, low DLC1 expression predicted a poor clinical outcome in patients with lung cancer. Together, our findings indicate that complex formation between the DLC1 START domain and CAV-1 contributes to DLC1 tumor suppression via a RhoGAP-independent mechanism, and suggest that DLC1 inactivation probably contributes to cancer progression.
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Affiliation(s)
- Xiaoli Du
- Laboratory of Cellular Oncology, Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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Thompson DE, Siwicky MD, Moorehead RA. Caveolin-1 expression is elevated in claudin-low mammary tumor cells. Cancer Cell Int 2012; 12:6. [PMID: 22356861 PMCID: PMC3305435 DOI: 10.1186/1475-2867-12-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 02/22/2012] [Indexed: 01/21/2023] Open
Abstract
Background Caveolin-1 is a scaffolding protein found in plasma membrane invaginations known as caveolae. Caveolin-1 can regulate a number of intracellular processes such as signal transduction, cholesterol metabolism and vesicular transport. With respect to breast cancer caveolin-1 has been observed in both tumor cells and stromal cells surrounding tumors however most of the recent research has focused on how the loss of caveolin-1 in the stromal cells surrounding the tumor alters the tumor microenvironment. Methods Caveolin-1 expression was evaluated in (1) mammary tumors induced by the transgenic overexpression of the type I insulin-like growth factor receptor (IGF-IR), (2) mammary tumors that became independent of IGF-IR signalling and acquired a claudin-low genotype, (3) two murine mammary epithelial tumor cell lines and (4) two murine mammary claudin-low tumor cell lines. Results We found that mammary tumors induced by IGF-IR overexpression expressed low levels of caveolin-1 while mammary tumors that became independent of IGF-IR signalling expressed considerably higher levels of caveolin-1. Interestingly, pockets of caveolin-1 positive cells could be observed in some of the IGF-IR-induced mammary tumors and these caveolin-1 positive cells were associated with tumor cells that expressed basal cytokeratins (cytokeratins 5 and 14). This caveolin-1 expression pattern was maintained in the murine mammary tumor cell lines in that the epithelial mammary tumor cell lines expressed little or no caveolin-1 while the claudin-low cell lines expressed caveolin-1. Conclusions Our model indicates that mammary tumor cells with epithelial characteristics lack caveolin-1 while mesenchymal tumor cells express caveolin-1 suggesting that caveolin-1 may serve as a marker of mammary tumor cells with mesenchymal characteristics such as claudin-low breast tumors.
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Affiliation(s)
- Devan E Thompson
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, 50 Stone Road East, Guelph, ON, Canada N1G2W1
| | - Megan D Siwicky
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, 50 Stone Road East, Guelph, ON, Canada N1G2W1
| | - Roger A Moorehead
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, 50 Stone Road East, Guelph, ON, Canada N1G2W1
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Abstract
The primary function of the mammalian lung is to facilitate diffusion of oxygen to venous blood and to ventilate carbon dioxide produced by catabolic reactions within cells. However, it is also responsible for a variety of other important functions, including host defense and production of vasoactive agents to regulate not only systemic blood pressure, but also water, electrolyte and acid-base balance. Caveolin-1 is highly expressed in the majority of cell types in the lung, including epithelial, endothelial, smooth muscle, connective tissue cells, and alveolar macrophages. Deletion of caveolin-1 in these cells results in major functional aberrations, suggesting that caveolin-1 may be crucial to lung homeostasis and development. Furthermore, generation of mutant mice that under-express caveolin-1 results in severe functional distortion with phenotypes covering practically the entire spectrum of known lung diseases, including pulmonary hypertension, fibrosis, increased endothelial permeability, and immune defects. In this Chapter, we outline the current state of knowledge regarding caveolin-1-dependent regulation of pulmonary cell functions and discuss recent research findings on the role of caveolin-1 in various pulmonary disease states, including obstructive and fibrotic pulmonary vascular and inflammatory diseases.
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Abstract
Caveolae are a specialized subset of lipid domains that are prevalent on the plasma membrane of endothelial cells. They compartmentalize signal transduction molecules which regulate multiple endothelial functions including the production of nitric oxide (NO) by the caveolae resident enzyme endothelial NO synthase (eNOS). eNOS is one of the three isoforms of the NOS enzyme which generates NO upon the conversion of L-arginine to L-citrulline and it is regulated by multiple mechanisms. Caveolin negatively impact eNOS activity through direct interaction with the enzyme. Circulating factors known to modify cardiovascular disease risk also influence the activity of the enzyme. In particular, high density lipoprotein cholesterol (HDL) maintains the lipid environment in caveolae, thereby promoting the retention and function of eNOS in the domain and it also causes direct activation of eNOS via scavenger receptor class B, Type I (SR-BI)-induced kinase signaling. Estrogen binding to estrogen receptors (ER) in caveolae also activates eNOS and this occurs through G protein coupling and kinase activation. Discrete domains within SR-BI and ER mediating signal initiation in caveolae have been identified. Counteracting the promodulatory actions of HDL and estrogen, C-reactive protein (CRP) antagonizes eNOS through FcγRIIB, which is the sole inhibitory receptor for IgG. Through their actions on eNOS, estrogen and CRP also regulate endothelial cell growth and migration. Thus, signaling events in caveolae invoked by known circulating cardiovascular disease risk factors have major impact on eNOS and endothelial cell phenotypes of importance to cardiovascular health and disease.
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Affiliation(s)
- Chieko Mineo
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Strålfors P. Caveolins and Caveolae, Roles in Insulin Signalling and Diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 729:111-26. [DOI: 10.1007/978-1-4614-1222-9_8] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Testa A, Spoto B, Sanguedolce MC, Parlongo RM, Pisano A, Tripepi G, Benedetto FA, Mallamaci F, Zoccali C. eNOS and caveolin-1 gene polymorphisms interaction and intima media thickness: a proof of concept study in ESRD patients. Am J Hypertens 2012; 25:103-8. [PMID: 21976276 DOI: 10.1038/ajh.2011.178] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Caveolae are a prominent microdomain in endothelial cells and appropriate localization in caveolae is fundamental for endothelial nitric oxide synthase (eNOS) activity. Since the Glu298Asp variant in the eNOS gene alters caveolar localization of the corresponding enzyme, we tested the interaction between this variant and the rs4730751 polymorphism of the caveolin-1 (CAV-1) gene as related to arterial remodeling in end-stage renal disease (ESRD) patients. METHODS One hundred and thirty-three ethnically homogeneous ESRD patients underwent carotid ultrasonographic studies to measure intima-media thickness (IMT) and carotid cross-sectional area (CSA). Genotyping was performed by high-throughput allelic discrimination assays on real-time PCR. RESULTS Arterial remodeling was associated to the number of G alleles of CAV-1 polymorphism, GG homozygotes displaying an IMT and a CSA that were, respectively, 16% and 21% higher than those in patients without the risk allele (P < 0.012). In multiple linear regression analyses including the CAV-1 and the eNOS polymorphisms and adjusting for classical risk factors and risk factors peculiar to ESRD both polymorphisms were independent correlates of IMT (CAV-1: β = 0.20, P = 0.01; eNOS β = 0.25, P = 0.001) and CSA (CAV-1: β = 0.20, P = 0.01: eNOS β = 0.13, P = 0.09). Furthermore, strong interactions emerged between the two polymorphisms for explaining the variability in IMT (P = 0.001) and in CSA (P = 0.038) in these patients. CONCLUSION Overall these findings form preliminary evidence that disturbed interaction between CAV-1 and eNOS may be of relevance for arterial disease in ESRD and perhaps in other human diseases.
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A genetic polymorphism in the CAV1 gene associates with the development of bronchiolitis obliterans syndrome after lung transplantation. FIBROGENESIS & TISSUE REPAIR 2011; 4:24. [PMID: 22040717 PMCID: PMC3215956 DOI: 10.1186/1755-1536-4-24] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 11/01/2011] [Indexed: 01/06/2023]
Abstract
Background Caveolin 1 (Cav-1) is the primary structural component of cell membrane invaginations called 'caveolae'. Expression of Cav-1 is implicated in the pathogenesis of pulmonary fibrosis. Genetic polymorphisms in the CAV1 gene influence the function of Cav-1 in malignancies and associate with renal allograft fibrosis. Chronic allograft rejection after lung transplantation, called 'bronchiolitis obliterans syndrome' (BOS), is also characterised by the development of fibrosis. In this study, we investigated whether CAV1 genotypes associate with BOS and whether Cav-1 serum levels are influenced by the CAV1 genotype and can be used as a biomarker to predict the development of BOS. Methods Twenty lung transplant recipients with BOS (BOSpos), ninety without BOS (BOSneg) and four hundred twenty-two healthy individuals donated DNA samples. Four SNPs in CAV1 were genotyped. Serial Cav-1 serum levels were measured in a matched cohort of 10 BOSpos patients and 10 BOSneg patients. Furthermore, single-time point Cav-1 serum levels were measured in 33 unmatched BOSneg patients and 60 healthy controls. Results Homozygosity of the minor allele of rs3807989 was associated with an increased risk for BOS (odds ratio: 6.13; P = 0.0013). The median Cav-1 serum level was significantly higher in the BOSpos patients than in the matched BOSneg patients (P = 0.026). Longitudinal analysis did not show changes in Cav-1 serum levels over time in both groups. The median Cav-1 serum level in the group of 43 BOSneg patients was lower than that in the healthy control group (P = 0.046). In lung transplant recipients, homozygosity of the minor allele of rs3807989 and rs3807994 was associated with increased Cav-1 serum levels. Conclusion In lung transplant recipients, the CAV1 SNP rs3807989 was associated with the development of BOS and Cav-1 serum levels were influenced by the CAV1 genotype.
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Biochemical and molecular aspects of vascular adrenergic regulation of blood pressure in the elderly. Int J Hypertens 2011; 2012:915057. [PMID: 21961055 PMCID: PMC3179865 DOI: 10.1155/2012/915057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 07/28/2011] [Indexed: 01/08/2023] Open
Abstract
Hypertension, orthostatic hypotension, arterial insufficiency, and atherosclerosis are common disorders in the elderly that lead to significant morbidity and mortality. One common factor to these conditions is an age-related decline in vascular beta-adrenergic receptor-mediated function and subsequent cAMP generation. Presently, there is no single cellular factor that can explain this age-related decline, and thus, the primary cause of this homeostatic imbalance is yet to be identified. However, the etiology is clearly associated with an age-related change in the ability of beta-adrenergic receptor to respond to agonist at the cellular level in the vasculature. This paper will review what is presently understood regarding the molecular and biochemical basis of age-impaired beta-adrenergic receptor-mediated signaling. A fundamental understanding of why β-AR-mediated vasorelaxation is impaired with age will provide new insights and innovative strategies for the management of multiple clinical disorders.
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Boopathi E, Gomes CM, Goldfarb R, John M, Srinivasan VG, Alanzi J, Malkowicz SB, Kathuria H, Zderic SA, Wein AJ, Chacko S. Transcriptional repression of Caveolin-1 (CAV1) gene expression by GATA-6 in bladder smooth muscle hypertrophy in mice and human beings. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2236-51. [PMID: 21514437 DOI: 10.1016/j.ajpath.2011.01.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 12/28/2010] [Accepted: 01/25/2011] [Indexed: 01/08/2023]
Abstract
Hypertrophy occurs in urinary bladder wall smooth muscle (BSM) in men with partial bladder outlet obstruction (PBOO) caused by benign prostatic hyperplasia (BPH) and in animal models of PBOO. Hypertrophied BSM from the rabbit model exhibits down-regulation of caveolin-1, a structural and functional protein of caveolae that function as signaling platforms to mediate interaction between receptor proteins and adaptor and effector molecules to regulate signal generation, amplification, and diversification. Caveolin-1 expression is diminished in PBOO-induced BSM hypertrophy in mice and in men with BPH. The proximal promoter of the human and mouse caveolin-1 (CAV1) gene was characterized, and it was observed that the transcription factor GATA-6 binds this promoter, causing reduced expression of caveolin-1. Furthermore, caveolin-1 expression levels inversely correlate with the abundance of GATA-6 in BSM hypertrophy in mice and human beings. Silencing of GATA6 gene expression up-regulates caveolin-1 expression, whereas overexpression of GATA-6 protein sustains the transcriptional repression of caveolin-1 in bladder smooth muscle cells. Together, these data suggest that GATA-6 acts as a transcriptional repressor of CAV1 gene expression in PBOO-induced BSM hypertrophy in men and mice. GATA-6-induced transcriptional repression represents a new regulatory mechanism of CAV1 gene expression in pathologic BSM, and may serve as a target for new therapy for BPH-induced bladder dysfunction in aging men.
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Affiliation(s)
- Ettickan Boopathi
- Division of Urology, University of Pennsylvania, Glenolden, Pennsylvania, USA
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Mastrodonato M, Calamita G, Rossi R, Mentino D, Bonfrate L, Portincasa P, Ferri D, Liquori GE. Altered distribution of caveolin-1 in early liver steatosis. Eur J Clin Invest 2011; 41:642-51. [PMID: 21250982 DOI: 10.1111/j.1365-2362.2010.02459.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Caveolin-1, the main structural protein of caveolae, is involved in cholesterol homoeostasis, transcytosis, endocytosis and signal transduction and thought to play an important role in lipidogenesis. Little is known about the pathophysiological role of caveolin-1 in nonalcoholic fatty liver disease (NAFLD), a condition frequently associated with the metabolic syndrome and characterized by abnormal accumulation of intrahepatic triglycerides with a potentially harmful risk of evolution to liver fibrosis, cirrhosis and hepatocellular carcinoma. MATERIALS AND METHODS Liver steatosis (micro/macrovesicular) was induced in adult rats fed a choline-deficient diet for 14days and compared with a control normal diet. The expression and subcellular distribution of caveolin-1 was assessed using light and electron microscopy by immunohistochemical and immunocytochemical techniques and by Western blotting. RESULTS Caveolin-1 was mainly associated with the hepatocyte basolateral plasma membrane. Fatty hepatocytes were characterized by a significant increase in the expression of caveolin-1 around and within the lipid droplets as well as in the inner membrane of mitochondria. CONCLUSIONS Our data suggest the involvement of caveolin-1 in the case of abnormal lipogenesis and mitochondrial function typical of steatotic hepatocytes in NAFLD. Addressing the role played by caveolin-1 in liver membranes in NAFLD may help future therapeutic choices in a frequent metabolic liver disease.
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Affiliation(s)
- Maria Mastrodonato
- Department of Animal and Environmental Biology, Aldo Moro University, Bari, Italy.
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Kunzmann S, Collins JJP, Yang Y, Uhlig S, Kallapur SG, Speer CP, Jobe AH, Kramer BW. Antenatal inflammation reduces expression of caveolin-1 and influences multiple signaling pathways in preterm fetal lungs. Am J Respir Cell Mol Biol 2011; 45:969-76. [PMID: 21562314 DOI: 10.1165/rcmb.2010-0519oc] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Bronchopulmonary dysplasia (BPD), associated with chorioamnionitis, results from the simultaneous effects of disrupted lung development, lung injury, and repair superimposed on the developing lung. Caveolins (Cavs) are implicated as major modulators of lung injury and remodeling by multiple signaling pathways, although Cavs have been minimally studied in the injured developing lung. We hypothesized that chorioamnionitis-associated antenatal lung inflammation would decrease the expression of Cav-1 in preterm fetal lungs. We tested whether changes occurred in the transcription factors Smad2/3, Smad1/5, Stat3, and Stat1, and we also studied the activation of acid-sphingomyelinase (a-SMase) with the generation of ceramide, along with changes in the expression of heme oxygenase-1 (HO-1) as indicators of possible Cav-1-mediated effects. Fetal sheep were exposed to 10 mg of intra-amniotic endotoxin or saline for 2, 7, or 2 + 7 days before preterm delivery at 124 days of gestation. The expression of Cav-1 and HO-1 and the phosphorylation of Smad and Stat were evaluated by real-time PCR, Western blotting, and/or immunohistochemistry. The activity of a-SMase and the concentrations of ceramide were measured. Intra-amniotic endotoxin decreased Cav-1 mRNA and protein expression in the lungs, with a maximum reduction of Cav-1 mRNA to 50% ± 7% of the control value (P < 0.05), and of Cav-1 protein expression to 20% ± 5% of the control value (P < 0.05). Decreased concentrations of Cav-1 were associated with the elevated phosphorylation of Smad2/3, Stat3, and Stat1, but not of Smad1/5. The expression of HO-1, a-SMase activity, and ceramide increased. Antenatal inflammation decreased the expression of Cav-1 in the preterm fetal lung. The decreased expression of Cav-1 was associated with the activation of the Smad2/3, Stat, and a-SMase/ceramide pathways, and with the increased expression of HO-1. The decreased concentrations of Cav-1 and changes in other signaling pathways may contribute to BPD.
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Affiliation(s)
- Steffen Kunzmann
- University Children's Hospital, University of Würzburg, Germany.
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Effects of estrogens on the expression of caveolin-1 in the urinary bladders of female rats. Int Neurourol J 2011; 15:13-8. [PMID: 21468281 PMCID: PMC3070219 DOI: 10.5213/inj.2011.15.1.13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 03/20/2011] [Indexed: 12/24/2022] Open
Abstract
PURPOSE The purposes of this study were to investigate the effect of hormonal alterations on the expression of caveolin-1 in the urinary bladders of ovariectomized rats and to determine the role of caveolin-1 in the overactivity of the detrusor muscle that occurs with hormonal alterations in rats. METHODS Female Sprague-Dawley rats were divided into three groups: a control group, a group that underwent bilateral ovariectomy (Ovx), and a group that underwent bilateral ovariectomy followed by subcutaneous injections of 17β-estradiol (Ovx+Est). After 4 weeks, urodynamic studies were done to measure the contraction interval and contraction pressure. The expression and cellular localization of caveolin-1 were determined by Western blot and immunofluorescence in the urinary bladders of rats. RESULTS On cystometrograms, the contraction interval was significantly shorter in the Ovx group (3.0±0.3 minute) than in the control group (5.6±0.5 minute) but was longer in the Ovx+Est group (9.2±0.4 minute) (P<0.05). Conversely, the average contraction pressure was higher in the Ovx group (26.4±0.48 mmHg) than in the control group (21.8±0.37 mmHg) but was lower in the Ovx+Est group (23.9±0.76 mmHg) (P<0.05). Caveolin-1 was expressed in the capillaries, arterioles, and venules. Expression of the protein caveolin-1 was significantly lower after ovariectomy and was restored to control levels after treatment with 17β-estradiol (P<0.05). CONCLUSIONS Hormonal alterations cause a significant change in the expression of caveolin-1, which suggests that caveolin-1 might have a functional role in the overactivity of the detrusor muscle related to hormonal alterations in the urinary bladders of rats.
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Sathish V, Yang B, Meuchel LW, VanOosten SK, Ryu AJ, Thompson MA, Prakash YS, Pabelick CM. Caveolin-1 and force regulation in porcine airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2011; 300:L920-9. [PMID: 21421751 DOI: 10.1152/ajplung.00322.2010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Caveolae are specialized membrane microdomains expressing the scaffolding protein caveolin-1. We recently demonstrated the presence of caveolae in human airway smooth muscle (ASM) and the contribution of caveolin-1 to intracellular calcium ([Ca(2+)](i)) regulation. In the present study, we tested the hypothesis that caveolin-1 regulates ASM contractility. We examined the role of caveolins in force regulation of porcine ASM under control conditions as well as TNF-α-induced airway inflammation. In porcine ASM strips, exposure to 10 mM methyl-β-cyclodextrin (CD) or 5 μM of the caveolin-1 specific scaffolding domain inhibitor peptide (CSD) resulted in time-dependent decrease in force responses to 1 μM ACh. Overnight exposure to the cytokine TNF-α (50 ng/ml) accelerated and increased caveolin-1 expression and enhanced force responses to ACh. Suppression of caveolin-1 with small interfering RNA mimicked the effects of CD or CSD. Regarding mechanisms by which caveolae contribute to contractile changes, inhibition of MAP kinase with 10 μM PD98059 did not alter control or TNF-α-induced increases in force responses to ACh. However, inhibiting RhoA with 100 μM fasudil or 10 μM Y27632 resulted in significant decreases in force responses, with lesser effects in TNF-α exposed samples. Furthermore, Ca(2+) sensitivity for force generation was substantially reduced by fasudil or Y27632, an effect even more enhanced in the absence of caveolin-1 signaling. Overall, these results indicate that caveolin-1 is a critical player in enhanced ASM contractility with airway inflammation.
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Affiliation(s)
- Venkatachalem Sathish
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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70
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Impact of oxLDL on Cholesterol-Rich Membrane Rafts. J Lipids 2011; 2011:730209. [PMID: 21490811 PMCID: PMC3066652 DOI: 10.1155/2011/730209] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 11/29/2010] [Indexed: 11/26/2022] Open
Abstract
Numerous studies have demonstrated that cholesterol-rich membrane rafts play critical roles in multiple cellular functions. However, the impact of the lipoproteins on the structure, integrity and cholesterol composition of these domains is not well understood. This paper focuses on oxidized low-density lipoproteins (oxLDLs) that are strongly implicated in the development of the cardiovascular disease and whose impact on membrane cholesterol and on membrane rafts has been highly controversial. More specifically, we discuss three major criteria for the impact of oxLDL on membrane rafts: distribution of different membrane raft markers, changes in membrane cholesterol composition, and changes in lipid packing of different membrane domains. We also propose a model to reconcile the controversy regarding the relationship between oxLDL, membrane cholesterol, and the integrity of cholesterol-rich membrane domains.
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71
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Kim J, Shin J, Park H. Structural characterization for N‐terminal domain of caveolin‐1. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/12265071.2003.9647706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Jongmin Kim
- a Department of Molecular Biology, College of Natural Sciences , Dankook University , Seoul , 140–714 , Korea
| | - Jaeyoung Shin
- a Department of Molecular Biology, College of Natural Sciences , Dankook University , Seoul , 140–714 , Korea
| | - Heonyong Park
- b Department of Molecular Biology, College of Natural Sciences , Dankook University , Seoul , 140–714 , Korea Phone: Fax: E-mail:
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Chen WC, Tzeng YS, Li H, Tien WS, Tsai YC. Lung defects in neonatal and adult stromal-derived factor-1 conditional knockout mice. Cell Tissue Res 2010; 342:75-85. [PMID: 20824284 DOI: 10.1007/s00441-010-1035-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 08/16/2010] [Indexed: 11/28/2022]
Abstract
Stromal-derived factor (SDF)-1/CXCL12 is a cytokine that is involved in organogenesis, hematopoiesis, chemoattraction, and wound healing. An SDF-1 knockout mouse (SDF-1(-/-)) has provided important insights into the role of SDF-1 in fetal development. Because the SDF-1 knockout is lethal in the perinatal period, we have created a conditional SDF-1 knockout mouse. In the present study, we induced conditionally knocked out SDF-1 in neonatal mice and found that lung development was compromised; neonatal lungs showed increased alveolar airspace and abnormal ultrastructure. Conditional knockout of SDF-1 in adult mice resulted in an emphysemic morphology, with increased alveolar airspace and thickened alveolar septa. Fluorescence angiography showed pulmonary vessel hyperdilation. To determine whether the hyperdilation involved nitric oxide, we inhibited endothelial nitric oxide synthase (eNOS) with N (G)-nitro-L- arginine methyl ester. This resulted in the inhibition of pulmonary vessel hyperdilation. Western blot results showed increased phosphorylation of eNOS in our induced SDF-1 knockout mice, indicating that eNOS is normally repressed in the presence of SDF-1, and that activation of eNOS contributes to pulmonary pathology. Thus, a conditional knockout mouse has been successfully created for SDF-1; initial characterization indicates that SDF-1 is intimately involved in lung development and physiology.
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Affiliation(s)
- Wen-Cheng Chen
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, 155, Sec. 2, Li-Nong Street, Pei-Tou, Taipei 11221, Taiwan
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73
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Chen SF, Liou JY, Huang TY, Lin YS, Yeh AL, Tam K, Tsai TH, Wu KK, Shyue SK. Caveolin-1 facilitates cyclooxygenase-2 protein degradation. J Cell Biochem 2010; 109:356-62. [PMID: 19960513 DOI: 10.1002/jcb.22407] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cyclooxygenase-2 (COX-2) plays major roles in diverse physiological and pathological processes such as inflammation and tumorigenesis. Transcriptional control of COX-2 has been extensively investigated and characterized, but its post-translational control is less clear. Here, we report a novel mechanism by which COX-2 is degraded. Protein levels of caveolin-1 (Cav-1) and COX-2 showed an inverse relation in colon cancer cell lines. COX-2 proteins in lung and colon tissues were higher in Cav-1 null mice than in wild-type mice. RNAi knockdown of Cav-1 increased COX-2 protein level and decreased ubiquitinated COX-2 accumulation. In addition, deletion of the carboxy (C)-terminus of COX-2, which contains a unique 19-amino acid segment compared with COX-1, resulted in reduced Cav-1 binding and attenuated COX-2 degradation. COX-1 and green fluorescence protein containing the C-terminus of COX-2 resulted in enhanced degradation. Our findings suggest that Cav-1 binds COX-2 in endoplasmic reticulum (ER) and carries it for degradation via ER associated degradation. The C-terminal region of COX-2 is required for Cav-1 binding and degradation. These results indicate a novel function of Cav-1 in controlling COX-2 expression, which may regulate physiological functions and have tumor suppression effects.
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Affiliation(s)
- Shu-Fen Chen
- Graduate School of Life Science, National Defense Medical Center, Taipei 114, Taiwan, ROC
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74
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MMTV promoter-regulated caveolin-1 overexpression yields defective parenchymal epithelia in multiple exocrine organs of transgenic mice. Exp Mol Pathol 2010; 89:9-19. [PMID: 20399205 DOI: 10.1016/j.yexmp.2010.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 03/31/2010] [Indexed: 01/21/2023]
Abstract
Caveolin-1 (Cav-1) is a major structural protein of caveolae, specialized plasma membrane invaginations that are involved in a cell-specific fashion in diverse cell activities such as molecular transport, cell adhesion, and signal transduction. In normal adult mammals, Cav-1 expression is abundant in mesenchyme-derived cells but relatively low in epithelial parenchyma. However, epithelial Cav-1 overexpression is associated with development and/or progression of many carcinomas. In this study, we generated and characterized a transgenic mouse model of Cav-1 overexpression under the control of a mouse mammary tumor virus (MMTV) long terminal-repeat promoter, which is predominantly expressed in specific epithelial cells. The MMTVcav-1(+) transgenic mice were fertile, and females bore litters of normal size with no obvious developmental abnormalities. However, by age 11months, the MMTVcav-1(+) mice demonstrated overtly different phenotypes in multiple exocrine organs when compared with their nontransgenic MMTVcav-1(-) littermates. Cav-1 overexpression in MMTVcav-1(+) mice produced organ-specific abnormalities, including hypotrophy of mammary glandular epithelia, bronchiolar epithelial hyperplasia and atypia, mucous-cell hyperplasia in salivary glands, elongated hair follicles and dermal thickening in the skin, and reduced accumulation of enzymogen granules in pancreatic acinar cells. In addition, the MMTVcav-1(+) transgenic mice tended to have a greater incidence of malignant tumors, including lung and liver carcinomas and lymphoma, than their MMTVcav-1(-) littermates. Our results indicate that Cav-1 overexpression causes organ-specific, age-related epithelial disorders and suggest the potential for increased susceptibility to carcinogenesis.
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75
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Sharma A, Yu C, Bernatchez PN. New insights into caveolae, caveolins and endothelial function. Can J Cardiol 2010; 26 Suppl A:5A-8A. [DOI: 10.1016/s0828-282x(10)71053-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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76
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González-Muñoz E, López-Iglesias C, Calvo M, Palacín M, Zorzano A, Camps M. Caveolin-1 loss of function accelerates glucose transporter 4 and insulin receptor degradation in 3T3-L1 adipocytes. Endocrinology 2009; 150:3493-502. [PMID: 19406948 DOI: 10.1210/en.2008-1520] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Caveolae are a specialized type of lipid rafts that are stabilized by oligomers of caveolin protein. Caveolae are particularly enriched in adipocytes. Here we analyzed the effects of caveolin-1 knockdown and caveolae ablation on adipocyte function. To this end, we obtained several multiclonal mouse 3T3-L1 cell lines with a reduced expression of caveolin-1 (95% reduction) by a small interfering RNA approach using lentiviral vectors. Control cell lines were obtained by lentiviral infection with lentiviral vectors encoding appropriate scrambled RNAs. Caveolin-1 knockdown adipocytes showed a drastic reduction in the number of caveolae (95% decrease) and cholera toxin labeling was reorganized in dynamic plasma membrane microdomains. Caveolin-1 depletion caused a specific decrease in glucose transporter 4 (GLUT4) and insulin receptor protein levels. This reduction was not the result of a generalized defect in adipocyte differentiation or altered gene expression but was explained by faster degradation of these proteins. Caveolin-1 knockdown adipocytes showed reductions in insulin-stimulated glucose transport, insulin-triggered GLUT4 recruitment to the cell surface, and insulin receptor activation. In all, our data indicate that caveolin-1 loss of function reduces maximal insulin response through lowered stability and diminished expression of insulin receptors and GLUT4. We propose that caveolin-1/caveolae control insulin action in adipose cells.
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Affiliation(s)
- Elena González-Muñoz
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Institute for Research in Biomedicine (IRB Barcelona), Serveis Cientifico-Tècnics, Universitat de Barcelona, 08028 Barcelona, Spain
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77
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Garg A, Agarwal AK. Lipodystrophies: disorders of adipose tissue biology. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1791:507-13. [PMID: 19162222 PMCID: PMC2693450 DOI: 10.1016/j.bbalip.2008.12.014] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 11/26/2008] [Accepted: 12/23/2008] [Indexed: 11/15/2022]
Abstract
The adipocytes synthesize and store triglycerides as lipid droplets surrounded by various proteins and phospholipids at its surface. Recently, the molecular basis of some of the genetic syndromes of lipodystrophies has been elucidated and some of these genetic loci have been found to contribute to lipid droplet formation in adipocytes. The two main types of genetic lipodystrophies are congenital generalized lipodystrophy (CGL) and familial partial lipodystrophy (FPL). So far, three CGL loci: 1-acylglycerol-3-phosphate-O-acyltransferase 2 (AGPAT2), Berardinelli-Seip Congenital Lipodystrophy 2 (BSCL2) and caveolin 1 (CAV1) and four FPL loci: lamin A/C (LMNA), peroxisome proliferator-activated receptor gamma (PPARG), v-AKT murine thymoma oncogene homolog 2 (AKT2) and zinc metalloprotease (ZMPSTE24), have been identified. AGPAT2 plays a critical role in the synthesis of glycerophospholipids and triglycerides required for lipid droplet formation. Another protein, seipin (encoded by BSCL2 gene), has been found to induce lipid droplet fusion. CAV1 is an integral component of caveolae and might contribute towards lipid droplet formation. PPARgamma and AKT2 play important role in adipogenesis and lipid synthesis. In this review, we discuss and speculate about the contribution of various lipodystrophy genes and their products in the lipid droplet formation.
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Affiliation(s)
- Abhimanyu Garg
- Division of Nutrition and Metabolic Diseases, Department of Internal Medicine, Center for Human Nutrition, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, USA.
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Mercier I, Casimiro MC, Zhou J, Wang C, Plymire C, Bryant KG, Daumer KM, Sotgia F, Bonuccelli G, Witkiewicz AK, Lin J, Tran TH, Milliman J, Frank PG, Jasmin JF, Rui H, Pestell RG, Lisanti MP. Genetic ablation of caveolin-1 drives estrogen-hypersensitivity and the development of DCIS-like mammary lesions. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 174:1172-90. [PMID: 19342371 DOI: 10.2353/ajpath.2009.080882] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Caveolin-1 (Cav-1) loss-of-function mutations are exclusively associated with estrogen receptor-positive (ER(+)) human breast cancers. To dissect the role of Cav-1 loss-of-function in the pathogenesis of human breast cancers, we used Cav-1(-/-) null mice as a model system. First, we demonstrated that Cav-1(-/-) mammary epithelia overexpress two well-established ER co-activator genes, CAPER and Foxa1, in addition to ER-alpha. Thus, the functional loss of Cav-1 may be sufficient to confer estrogen-hypersensitivity in the mammary gland. To test this hypothesis directly, we subjected Cav-1(-/-) mice to ovariectomy and estrogen supplementation. As predicted, Cav-1(-/-) mammary glands were hyper-responsive to estrogen and developed dysplastic mammary lesions with adjacent stromal angiogenesis that resemble human ductal carcinoma in situ. Based on an extensive biomarker analysis, these Cav-1(-/-) mammary lesions contain cells that are hyperproliferative and stain positively with nucleolar (B23/nucleophosmin) and stem/progenitor cell markers (SPRR1A and beta-catenin). Genome-wide transcriptional profiling identified many estrogen-related genes that were over-expressed in Cav-1(-/-) mammary glands, including CAPER--an ER co-activator gene and putative stem/progenitor cell marker. Analysis of human breast cancer samples revealed that CAPER is overexpressed and undergoes a cytoplasmic-to-nuclear shift during the transition from pre-malignancy to ductal carcinoma in situ. Thus, Cav-1(-/-) null mice are a new preclinical model for studying the molecular paradigm of estrogen hypersensitivity and the development of estrogen-dependent ductal carcinoma in situ lesions.
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Affiliation(s)
- Isabelle Mercier
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA 19107, USA
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79
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Hamelers IHL, Staffhorst RWHM, Voortman J, de Kruijff B, Reedijk J, van Bergen en Henegouwen PMP, de Kroon AIPM. High cytotoxicity of cisplatin nanocapsules in ovarian carcinoma cells depends on uptake by caveolae-mediated endocytosis. Clin Cancer Res 2009; 15:1259-68. [PMID: 19228729 DOI: 10.1158/1078-0432.ccr-08-1702] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Cisplatin nanocapsules, nanoprecipitates of cisplatin encapsulated in phospholipid bilayers, exhibit increased in vitro toxicity compared with the free drug toward a panel of human ovarian carcinoma cell lines. To elucidate the mechanism of cell killing by nanocapsules and to understand the cell line dependence of nanocapsule efficacy, the route of uptake and the intracellular fate of the nanocapsules were investigated. EXPERIMENTAL DESIGN Intracellular platinum accumulation and cisplatin-DNA-adduct formation were measured in cell lines that differ in sensitivity to cisplatin nanocapsules. Confocal fluorescence microscopy in combination with down-regulation with small interfering RNA was used to map the route of cellular uptake of nanocapsules containing fluorescein-labeled cisplatin. RESULTS In sensitive cell lines, cisplatin from nanocapsules is taken up much more efficiently than the free compound. In IGROV-1 cells, the increased platinum accumulation results in augmented cisplatin-DNA-adduct formation. Confocal fluorescence microscopy revealed that the uptake of nanocapsules is energy dependent. Colocalization with markers of early and late endosomes indicated uptake via endocytosis. Down-regulation of caveolin-1 with small interfering RNA inhibited the uptake and cytotoxic effect of nanocapsules in IGROV-1 cells. Ovarian carcinoma cells, in which the nanocapsules are less effective than in IGROV-1 cells, do not internalize the nanocapsules (OVCAR-3) or accumulate them in an endocytic compartment after clathrin-mediated endocytosis (A2780). CONCLUSIONS The high cytotoxicity of cisplatin nanocapsules requires caveolin-1-dependent endocytosis that is followed by release of the drug from a late endosomal/lysosomal compartment and cisplatin-DNA-adduct formation. The findings may be applied in predicting the efficacy of nanoparticulate anticancer drug delivery systems in treating different tumor types.
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Affiliation(s)
- Irene H L Hamelers
- Biochemistry of Membranes, Bijvoet Institute, Department of Cellular Architecture and Dynamics, Utrecht University, Utrecht, The Netherlands
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80
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Romanenko VG, Roser KS, Melvin JE, Begenisich T. The role of cell cholesterol and the cytoskeleton in the interaction between IK1 and maxi-K channels. Am J Physiol Cell Physiol 2009; 296:C878-88. [PMID: 19176762 DOI: 10.1152/ajpcell.00438.2008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recently, we demonstrated a novel interaction between large-conductance (maxi-K or K(Ca)1.1) and intermediate-conductance (IK1 or K(Ca)3.1) Ca(2+)-activated K channels: activation of IK1 channels causes the inhibition of maxi-K activity (Thompson J and Begenisich T. J Gen Physiol 127: 159-169, 2006). Here we show that the interaction between these two channels can be regulated by the membrane cholesterol level in parotid acinar cells. Depletion of cholesterol using methyl-beta-cyclodextrin weakened, while cholesterol enrichment increased, the ability of IK1 activation to inhibit maxi-K channels. Cholesterol's stereoisomer, epicholesterol, was unable to substitute for cholesterol in the interaction between the two K channels, suggesting a specific cholesterol-protein interaction. This suggestion was strengthened by the results of experiments in which cholesterol was replaced by coprostanol and epicoprostanol. These two sterols have nearly identical effects on membrane physical properties and cholesterol-rich microdomain stability, but had very different effects on the IK1/maxi-K interaction. In addition, the IK1/maxi-K interaction was unaltered in cells lacking caveolin, the protein essential for formation and stability of caveolae. Finally, disruption of the actin cytoskeleton restored the IK1-induced maxi-K inhibition that was lost with cell cholesterol depletion, demonstrating the importance of an intact cytoskeleton for the cholesterol-dependent regulation of the IK1/maxi-K interaction.
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Affiliation(s)
- Victor G Romanenko
- Dept. of Pharmacology, Box 711, Univ. of Rochester Medical Center, Rochester, NY 14642, USA
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81
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Gherghiceanu M, Hinescu ME, Popescu LM. Myocardial interstitial Cajal-like cells (ICLC) in caveolin-1 KO mice. J Cell Mol Med 2009; 13:202-6. [PMID: 19175701 PMCID: PMC3823047 DOI: 10.1111/j.1582-4934.2008.00615.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Accepted: 12/22/2008] [Indexed: 11/29/2022] Open
Abstract
Abstract We compared, by transmission electron microscopy (TEM), the ultrastructure of interstitial Cajal-like cells (ICLC) in normal mammalian myocardium versus caveolin-1 null mice. TEM showed that myocardial ICLCs of caveolin-1-deficient mice retain their main ultrastructural characteristics, for example, location among cardiomyocytes, close vicinity to nerves and/or blood capillaries, specialized cell-to-cell junctions, presence of 2-3 typical processes, which are very long (several tens of micrometres), but are very thin (0.1-0.2 microm) and moniliform. However, the most striking modification of myocardial ICLC in caveolin-1 KO mice was the absence of caveolae. Beyond this main observation, three other findings could be reported: (1) the absence of caveolae in capillary endothelium, (2) persistence of (some) caveolae at the level of cardiomyocte sarcolemma or vascular smooth muscle cell sarcolemma and (3) (un)expected ultrastructural modifications such as increased thickness of capillary basement membrane and increased autophagy of several cardiomyocytes.
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Affiliation(s)
- M Gherghiceanu
- ‘Victor Babes’ National Institute of Pathology, Bucharest, Romania
| | - M E Hinescu
- ‘Victor Babes’ National Institute of Pathology, Bucharest, Romania
- Department of Cellular and Molecular Medicine, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest, Romania
| | - L M Popescu
- ‘Victor Babes’ National Institute of Pathology, Bucharest, Romania
- Department of Cellular and Molecular Medicine, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest, Romania
- ‘I. Cantacuzino’ Institute, Bucharest, Romania
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82
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Caveolin-1, transforming growth factor-β receptor internalization, and the pathogenesis of systemic sclerosis. Curr Opin Rheumatol 2008; 20:713-9. [DOI: 10.1097/bor.0b013e3283103d27] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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83
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Nitric oxide synthases are crucially involved in the development of the severe cardiomyopathy of caveolin-1 knockout mice. Biochem Biophys Res Commun 2008; 377:769-74. [PMID: 18951881 DOI: 10.1016/j.bbrc.2008.10.068] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Accepted: 10/08/2008] [Indexed: 11/22/2022]
Abstract
Targeted ablation of caveolin-1 (cav-1) results in a severe cardiomyopathy. How the loss of cav-1 mediates these abnormalities is currently under investigation. Mounting evidence indicates that cav-1 acts as a negative regulator of endothelial nitric oxide synthase resulting in a constitutive hyperactivation of the nitric oxide (NO)-pathway in cav-1 knockout mice (cav-1 ko). In this context we hypothesized that disturbed NO signalling is implicated in these changes. To explore this question cav-1 ko were compared with knockout counterparts experiencing 2 month postnatal NO synthase inhibition by N(G)-nitro-l-arginine methyl ester (l-NAME) treatment. Chronic l-NAME treatment resulted in significant improvements in heart function and exercise capacity in cav-1 ko. Furthermore, we found evidence for an enhanced radical stress in hearts of cav-1 ko which was markedly reduced by l-NAME treatment. Collectively, these findings suggest that NO synthases play a crucial role in the evolution of heart failure evident in cav-1 ko.
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84
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Hahn-Obercyger M, Graeve L, Madar Z. A high-cholesterol diet increases the association between caveolae and insulin receptors in rat liver. J Lipid Res 2008; 50:98-107. [PMID: 18757837 DOI: 10.1194/jlr.m800441-jlr200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Caveolin-1, a component of caveolae, regulates signaling pathway compartmentalization by interacting with tyrosine (Tyr) kinase receptors and their substrates. Perturbations in caveolae lipid composition have been shown in vitro to displace proteins from lipid microdomains, thereby altering their functionality and subsequent downstream signaling. The role of caveolin-1 in insulin receptor (IR) signaling has been widely investigated in vitro mainly in 3T3-L1 adipocyte cells. However, in vivo experiments investigating this connection in liver tissue have not been carried out. The objective of the present study was to investigate the effects of a high-cholesterol diet on caveolin-1 expression and IR localization and activity in the rat liver. Compared with a standard diet, rats fed with diet rich in cholesterol significantly altered liver caveolae by increasing both caveolin-1 (66%, P < 0.05) and caveolin-2 (55%, P < 0.05) expression while caveolin-1 mRNA levels were reduced. Concomitantly, a 25% increase in localization of the caveolae-resident signaling protein IR was observed. The distribution of caveolar and noncaveolar phosphorylated IR was unaffected but insulin-induced IR activation was significantly enhanced following consumption of the high-cholesterol diet (120%, P < 0.001). However, the downstream molecules IRS-1 and Akt have shown impaired activity in cholesterol-fed rats suggesting insulin resistance condition. Insulin stimulation failed to induce Tyr phosphorylation of caveolin-1 in cholesterol-fed rats. These findings suggest a mechanism by which a high-cholesterol diet altered caveolin-1 expression in vivo accompanied by altered IR localization and activity.
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Affiliation(s)
- Michal Hahn-Obercyger
- The Hebrew University of Jerusalem, Faculty of Agricultural, Food and Environmental Quality Sciences, Institute of Biochemistry, Food Science and Nutrition, Rehovot, Israel
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Wunderlich C, Schmeisser A, Heerwagen C, Ebner B, Schober K, Braun-Dullaeus RC, Schwencke C, Kasper M, Morawietz H, Strasser RH. Chronic NOS inhibition prevents adverse lung remodeling and pulmonary arterial hypertension in caveolin-1 knockout mice. Pulm Pharmacol Ther 2008; 21:507-15. [DOI: 10.1016/j.pupt.2007.11.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Revised: 11/08/2007] [Accepted: 11/21/2007] [Indexed: 01/08/2023]
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86
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Wunderlich C, Schober K, Schmeisser A, Heerwagen C, Tausche AK, Steinbronn N, Brandt A, Kasper M, Schwencke C, Braun-Dullaeus RC, Strasser RH. The adverse cardiopulmonary phenotype of caveolin-1 deficient mice is mediated by a dysfunctional endothelium. J Mol Cell Cardiol 2008; 44:938-47. [PMID: 18417152 DOI: 10.1016/j.yjmcc.2008.02.275] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2007] [Revised: 02/18/2008] [Accepted: 02/20/2008] [Indexed: 11/20/2022]
Abstract
Recently generated caveolin-1 deficient mice (cav-1(-/-)) display several physiological alterations such as severe heart failure and lung fibrosis. The molecular mechanisms how the loss of caveolin-1 (cav-1) mediates these alterations are currently under debate. A plethora of studies support a role of cav-1 as a negative regulator of endothelial nitric oxide synthase (eNOS). Accordingly, constitutive eNOS hyperactivation was observed in cav-1(-/-). Given the hyperactivated eNOS enzyme we hypothesized that disturbed eNOS function is involved in the development of the cardiopulmonary pathologies in cav-1(-/-). The present study argues that loss of cav-1 results in enhanced eNOS activity but not in increased vascular tetrahydrobiopterin (BH(4)) levels (which acts as an essential eNOS cofactor) thereby causing a stoichiometric discordance between eNOS activity and BH(4) sufficient to cause dysfunctional eNOS signaling. The resultant oxidative stress is largely responsible for major cardiac and pulmonary defects observed in cav-1(-/-). BH(4) donation to cav-1(-/-) led to a normalized BH(4)/BH(2) ratio, to reduced oxidant stress, to substantial improvements of both systolic and diastolic heart function and to marked amelioration of the impaired lung phenotype. Notably, the antioxidant tetrahydroneopterin which is not essential for eNOS function showed no relevant effect. Taken together these novel findings indicate that dysfunctional eNOS is of central importance in the genesis of the cardiopulmonary phenotype of cav-1(-/-). Additionally, these findings are generally of paramount importance since they underline the deleterious role of an uncoupled eNOS in cardiovascular pathology and they additionally suggest BH(4) as an effective cure.
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Affiliation(s)
- Carsten Wunderlich
- University of Technology Dresden, Department of Medicine and Cardiology, Medical Clinic, Fetscherstr. 76, Dresden 01307, Germany.
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87
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A translational view on the biliary lipid secretory network. Biochim Biophys Acta Mol Cell Biol Lipids 2008; 1781:79-96. [DOI: 10.1016/j.bbalip.2007.12.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Revised: 11/28/2007] [Accepted: 12/13/2007] [Indexed: 01/26/2023]
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88
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Silva WI, Maldonado HM, Velázquez G, García JO, González FA. Caveolins in glial cell model systems: from detection to significance. J Neurochem 2008; 103 Suppl 1:101-12. [PMID: 17986145 DOI: 10.1111/j.1471-4159.2007.04712.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Glial cells prevail in number and in diversity of cellular phenotypes in the nervous system. They have also gained prominence due to their multiple physiological and pathophysiological roles. Our current knowledge of the asymmetry and heterogeneity of the plasma membrane demands an in depth analysis of the diverse array of membrane microdomains postulated to exist in the context of glial cells. This review focuses and analyzes the studies reported to date on the detection of caveolae membrane rafts and the caveolin family members in glial cell model systems, the conditions leading to changes in their level of expression, and their functional and clinical significance. Outstanding in this work emerge the ubiquitous expression of caveolins, including the typically regarded 'muscle-specific' cav3, in diverse glial cell model systems, their participation in reactive astrogliosis, cancer, and their key relevance to calcium signaling. The knowledge obtained to date demands incorporation of the caveolins and caveolae membrane rafts in our current models on the role of glial cells in heath and neurological disease.
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Affiliation(s)
- W I Silva
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
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89
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Kathuria H, Cao Y, Hinds A, Ramirez MI, Williams MC. ERM is expressed by alveolar epithelial cells in adult mouse lung and regulates caveolin-1 transcription in mouse lung epithelial cell lines. J Cell Biochem 2007; 102:13-27. [PMID: 17390339 DOI: 10.1002/jcb.21270] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We previously identified an Ets cis-element in the mouse caveolin-1 promoter that is selectively activated in lung epithelial (E10), but not lung endothelial murine lung endothelial cell line (MFLM-4), cell lines and therefore appears important for differential, cell-specific caveolin-1 transcription. In the present study, we demonstrate that immunostaining of adult mouse lung detects the ETS protein Ets-related molecule (ERM PEA3) in distal lung epithelium in alveolar type I and II cells, but not in bronchial epithelium or lung endothelial cells. We tested ERM and polyomavirus enhancer activator 3 (PEA3) for their ability to increase endogenous caveolin-1 transcripts and to activate caveolin-1 promoter fragments containing the -865 Ets cis-element. Chromatin immunoprecipitation (ChIP) assays show that both ERM and PEA3 bind to the caveolin-1 promoter in murine E10, but not MFLM-4, cells. Normalized luciferase activities show that only ERM activates the caveolin-1 promoter in E10 cells, but neither protein enhances promoter activity in MFLM-4 cells. Mutation of the Ets site blocks ERM-mediated promoter activation in E10 cells. Furthermore, overexpression of ERM increases the cellular content of caveolin-1 mRNA and protein, in E10, but not MFLM-4, cells. The effects of PEA3 on the cellular content of endogenous caveolin-1 expression are variable. These results demonstrate that ERM is involved in caveolin-1 regulation in a murine lung epithelial, but not lung endothelial cell line. We conclude that transcriptional regulation of caveolin-1 differs markedly between lung epithelial and endothelial cell lines, perhaps explaining why the onset of caveolin-1 expression differs in epithelial and endothelial cells during lung development.
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Affiliation(s)
- Hasmeena Kathuria
- Department of Medicine, Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
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90
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Mayoral R, Fernández-Martínez A, Roy R, Boscá L, Martín-Sanz P. Dispensability and dynamics of caveolin-1 during liver regeneration and in isolated hepatic cells. Hepatology 2007; 46:813-22. [PMID: 17654701 DOI: 10.1002/hep.21746] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
UNLABELLED Caveolae participate in several cellular processes such as vesicular transport, cholesterol homeostasis, regulation of signal transduction, integrin signaling, and cell growth. The expression and functional role of caveolin (Cav), the most abundant protein of caveolae, has been reported in liver and in different hepatocyte cell lines, in human cirrhotic liver, and in hepatocellular carcinomas. The role of Cav-1 in liver regeneration after partial hepatectomy (PH) has been investigated as a model of liver proliferation in vivo. Our results show that Cav-1 increases in liver after PH with a redistribution of the protein from the caveola-enriched domain to the noncaveolar fraction. Moreover, the Cav-1 located in the noncaveolar fraction is phosphorylated in tyrosine 14, even though the Cav-1 gene is dispensable for liver regeneration after PH, as deduced from data obtained with commercially available animals lacking this gene. In addition to this, the proinflammatory stimulation of hepatocytes induces Cav-1 translocation to a noncaveolar fraction and tyrosine 14 phosphorylation mainly through the activation of tyrosine kinases such as Src. CONCLUSION These results support a dynamic role for Cav-1 in liver proliferation both in vivo after PH and in vitro in cultured hepatic cell lines, but with minimal implications for the liver regeneration process.
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Affiliation(s)
- Rafael Mayoral
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
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91
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Prakash YS, Thompson MA, Vaa B, Matabdin I, Peterson TE, He T, Pabelick CM. Caveolins and intracellular calcium regulation in human airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2007; 293:L1118-26. [PMID: 17704188 DOI: 10.1152/ajplung.00136.2007] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Regulation of intracellular Ca(2+) concentration ([Ca(2+)](i)) is a key factor in airway smooth muscle (ASM) tone. In vascular smooth muscle, specialized membrane microdomains (caveolae) expressing the scaffolding protein caveolin-1 are thought to facilitate cellular signal transduction. In human ASM cells, we tested the hypothesis that caveolae mediate Ca(2+) responses to agonist stimulation. Fluorescence immunocytochemistry with confocal microscopy, as well as Western blot analysis, was used to determine that agonist receptors (M(3) muscarinic, bradykinin, and histamine) and store-operated Ca(2+) entry (SOCE)-regulatory mechanisms colocalize with caveolin-1. Although caveolin-2 coexpressed with caveolin-1, caveolin-3 was absent. In fura 2-loaded ASM cells, [Ca(2+)](i) responses to 1 microM ACh, 10 microM histamine, and 10 nM bradykinin, as well as SOCE, were attenuated (each to a different extent) after disruption of caveolae by the cholesterol-chelating drug methyl-beta-cyclodextrin. Transfection of ASM cells with 50 nM caveolin-1 small interfering RNA significantly weakened caveolin-1 expression and blunted [Ca(2+)](i) responses to bradykinin and histamine, as well as SOCE, but the response to ACh was less intense. These results indicate that caveolae are present in ASM and that caveolin-1 contributes to regulation of [Ca(2+)](i) responses to agonist.
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Affiliation(s)
- Y S Prakash
- Departments of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA .
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92
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Predescu SA, Predescu DN, Malik AB. Molecular determinants of endothelial transcytosis and their role in endothelial permeability. Am J Physiol Lung Cell Mol Physiol 2007; 293:L823-42. [PMID: 17644753 DOI: 10.1152/ajplung.00436.2006] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Caveolae transcytosis with its diverse mechanisms-fluid phase, adsorptive, and receptor-mediated-plays an important role in the continuous exchange of molecules across the endothelium. We will discuss key features of endothelial transcytosis and caveolae that have been studied recently and have increased our understanding of caveolae function in transcytosis at the molecular level. During transcytosis, caveolae "pinch off" from the plasma membrane to form discrete vesicular carriers that shuttle to the opposite front of endothelial cells, fuse with the plasma membrane, and discharge their cargo into the perivascular space. Endothelial transcytosis exhibits distinct properties, the most important being rapid and efficient coupling of endocytosis to exocytosis on opposite plasma membrane. We address herein the membrane fusion-fission reactions that underlie transcytosis. Caveolae move across the endothelial cells with their cargo predominantly in the fluid phase through an active process that bypasses the lysosomes. Endothelial transcytosis is a constitutive process of vesicular transport. Recent studies show that transcytosis can be upregulated in response to pathological stimuli. Transcytosis via caveolae is an important route for the regulation of endothelial barrier function and may participate in different vascular diseases.
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Affiliation(s)
- Sanda A Predescu
- Department of Pharmacology and Center for Lung and Vascular Biology, University of Illinois, College of Medicine, Chicago, Illinois 60612, USA
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93
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Nixon SJ, Carter A, Wegner J, Ferguson C, Floetenmeyer M, Riches J, Key B, Westerfield M, Parton RG. Caveolin-1 is required for lateral line neuromast and notochord development. J Cell Sci 2007; 120:2151-61. [PMID: 17550965 DOI: 10.1242/jcs.003830] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Caveolae have been linked to diverse cellular functions and to many disease states. In this study we have used zebrafish to examine the role of caveolin-1 and caveolae during early embryonic development. During development, expression is apparent in a number of tissues including Kupffer's vesicle, tailbud, intersomite boundaries, heart, branchial arches, pronephric ducts and periderm. Particularly strong expression is observed in the sensory organs of the lateral line, the neuromasts and in the notochord where it overlaps with expression of caveolin-3. Morpholino-mediated downregulation of Cav1alpha caused a dramatic inhibition of neuromast formation. Detailed ultrastructural analysis, including electron tomography of the notochord, revealed that the central regions of the notochord has the highest density of caveolae of any embryonic tissue comparable to the highest density observed in any vertebrate tissue. In addition, Cav1alpha downregulation caused disruption of the notochord, an effect that was enhanced further by Cav3 knockdown. These results indicate an essential role for caveolin and caveolae in this vital structural and signalling component of the embryo.
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Affiliation(s)
- Susan J Nixon
- Institute for Molecular Bioscience, University of Queensland, Brisbane 4072, Australia
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94
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Savage K, Lambros MBK, Robertson D, Jones RL, Jones C, Mackay A, James M, Hornick JL, Pereira EM, Milanezi F, Fletcher CDM, Schmitt FC, Ashworth A, Reis-Filho JS. Caveolin 1 is overexpressed and amplified in a subset of basal-like and metaplastic breast carcinomas: a morphologic, ultrastructural, immunohistochemical, and in situ hybridization analysis. Clin Cancer Res 2007; 13:90-101. [PMID: 17200343 DOI: 10.1158/1078-0432.ccr-06-1371] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The distribution and significance of caveolin 1 (CAV1) expression in different breast cell types and role in breast carcinogenesis remain poorly understood. Both tumor-suppressive and oncogenic roles have been proposed for this protein. The aims of this study were to characterize the distribution of CAV1 in normal breast, benign breast lesions, breast cancer precursors, and metaplastic breast carcinomas; to assess the prognostic significance of CAV1 expression in invasive breast carcinomas; and to define whether CAV1 gene amplification is the underlying genetic mechanism driving CAV1 overexpression in breast carcinomas. EXPERIMENTAL DESIGN CAV1 distribution in frozen and paraffin-embedded whole tissue sections of normal breast was evaluated using immunohistochemistry, immunofluorescence, and immunoelectron microscopy. CAV1 expression was immunohistochemically analyzed in benign lesions, breast cancer precursors, and metaplastic breast carcinomas and in a cohort of 245 invasive breast carcinomas from patients treated with surgery followed by anthracycline-based chemotherapy. In 25 cases, CAV1 gene amplification was assessed by chromogenic in situ hybridization. RESULTS In normal breast, CAV1 was expressed in myoepithelial cells, endothelial cells, and a subset of fibroblasts. Luminal epithelial cells showed negligible staining. CAV1 was expressed in 90% of 39 metaplastic breast carcinomas and in 9.4% of 245 invasive breast cancers. In the later cohort, CAV1 expression was significantly associated with 'basal-like' immunophenotype and with shorter disease-free and overall survival on univariate analysis. CAV1 gene amplification was found in 13% of cases with strong CAV1 expression. CONCLUSIONS The concurrent CAV1 amplification and overexpression call into question its tumor-suppressive effects in basal-like breast carcinomas.
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Affiliation(s)
- Kay Savage
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research, London, United Kingdom
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95
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Callera GE, Montezano AC, Yogi A, Tostes RC, Touyz RM. Vascular signaling through cholesterol-rich domains: implications in hypertension. Curr Opin Nephrol Hypertens 2007; 16:90-104. [PMID: 17293683 DOI: 10.1097/mnh.0b013e328040bfbd] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW Lipid rafts are emerging as key players in the integration of cellular responses. Alterations in these highly regulated signaling cascades are important in structural, mechanical and functional abnormalities that underlie vascular pathological processes. The present review focuses on recent advances in signal transduction through caveolae/lipid rafts, implicated in hypertensive processes. RECENT FINDINGS Caveolae/lipid rafts function as sites of dynamic regulatory events in receptor-induced signal transduction. Mediators of vascular function, including G-protein coupled receptors, Src family tyrosine kinases, receptor tyrosine kinases, protein phosphatases and nitric oxide synthase, are concentrated within these microdomains. The assembly of functionally active nicotinamide adenine dinucleotide phosphate oxidase and subsequent reactive oxygen species production are also dependent on interactions within the caveolae/lipid rafts. Recent findings have also demonstrated the importance of actin-cytoskeleton and focal adhesion sites for protein interactions with caveolae/lipid raft. SUMMARY Many vascular signaling processes are altered in hypertension. Whether these events involve lipid rafts/caveolae remains unclear. A better understanding of how signaling molecules compartmentalize in lipid rafts/caveolae will provide further insights into molecular mechanisms underlying vascular damage in cardiovascular disease.
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Affiliation(s)
- Glaucia E Callera
- Kidney Research Centre, Ottawa Health Research Institute, University of Ottawa, Ottawa, Canada.
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96
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Carlile-Klusacek M, Rizzo V. Endothelial cytoskeletal reorganization in response to PAR1 stimulation is mediated by membrane rafts but not caveolae. Am J Physiol Heart Circ Physiol 2007; 293:H366-75. [PMID: 17369462 DOI: 10.1152/ajpheart.01044.2006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The vasoactive protease thrombin is a known activator of the protease-activated receptor-1 (PAR1) via cleavage of its NH(2) terminus. PAR1 activation stimulates the RhoA/Rho kinase signaling cascade, leading to myosin light chain (MLC) phosphorylation, actin stress fiber formation, and changes in endothelial monolayer integrity. Previous studies suggest that some elements of this signaling pathway are localized to caveolin-containing cholesterol-rich membrane domains. Here we show that PAR1 and key components of the PAR-associated signaling cascade localize to membrane rafts and caveolae in bovine aortic endothelial cells (BAEC). To investigate the functional significance of this localization, BAEC were pretreated with filipin (5 mug/ml, 5 min) to ablate lipid rafts before thrombin (100 nM) or PAR agonist stimulation. We found that diphosphorylation of MLC and the actin stress fiber formation normally induced by PAR activation were attenuated after lipid raft disruption. To target caveolae specifically, we used a small interferring RNA approach to knockdown caveolin-1 expression. Thrombin-induced MLC phosphorylation and stress fiber formation were not altered in caveolin-1-depleted cells, suggesting that lipid rafts, but not necessarily caveolae, modulate thrombin-activated signaling pathways leading to alteration of the actin cytoskeleton in endothelial cells.
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Affiliation(s)
- Maryellen Carlile-Klusacek
- Cardiovascular Research Center and Dept. of Anatomy & Cell Biology, Temple University School of Medicine, 3420 N. Broad Street, Philadelphia, PA 19140, USA
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97
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Abstract
Lipid rafts and their related membrane vesicular structures, caveolae, are cholesterol- and sphingolipid-rich microdomains of the plasma membrane that have attracted considerable interest because of their ability to concentrate numerous signaling proteins. Efforts to define the proteins that reside in lipid rafts and caveolae as well as investigations into the functional role of these microdomains in signaling, endocytosis, and other cellular processes have led to the hypothesis that they compartmentalize or prearrange molecules involved in regulating these pathways. This chapter describes biochemical approaches for defining lipid rafts and caveolae. Included are detergent- and nondetergent-based fractionations on sucrose-density gradients that isolate buoyant lipid rafts and caveolae as well as caveolin antibody-based immunoisolation of detergent-insoluble membranes that selectively isolates caveolae and not lipid rafts. Also, a general method to disrupt lipid rafts and caveolae using beta-cyclodextrin that is useful for probing the role of these microdomains in cellular processes is described. The advantages and disadvantages of the respective approaches are discussed. Taken together, these methods are useful for defining the role of lipid rafts and caveolae in cell signaling.
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Affiliation(s)
- Rennolds S Ostrom
- Department of Pharmacology and the Vascular Biology Center of Excellence, The University of Tennessee Health Science Center, Memphis, USA
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98
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Williams TM, Sotgia F, Lee H, Hassan G, Di Vizio D, Bonuccelli G, Capozza F, Mercier I, Rui H, Pestell RG, Lisanti MP. Stromal and epithelial caveolin-1 both confer a protective effect against mammary hyperplasia and tumorigenesis: Caveolin-1 antagonizes cyclin D1 function in mammary epithelial cells. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 169:1784-801. [PMID: 17071600 PMCID: PMC1780215 DOI: 10.2353/ajpath.2006.060590] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Here, we investigate the role of caveolin-1 (Cav-1) in breast cancer onset and progression, with a focus on epithelial-stromal interactions, ie, the tumor microenvironment. Cav-1 is highly expressed in adipocytes and is abundant in mammary fat pads (stroma), but it remains unknown whether loss of Cav-1 within mammary stromal cells affects the differentiated state of mammary epithelia via paracrine signaling. To address this issue, we characterized the development of the mammary ductal system in Cav-1-/- mice and performed a series of mammary transplant studies, using both wild-type and Cav-1-/- mammary fat pads. Cav-1-/- mammary epithelia were hyperproliferative in vivo, with dramatic increases in terminal end bud area and mammary ductal thickness as well as increases in bromodeoxyuridine incorporation, extracellular signal-regulated kinase-1/2 hyperactivation, and up-regulation of STAT5a and cyclin D1. Consistent with these findings, loss of Cav-1 dramatically exacerbated mammary lobulo-alveolar hyperplasia in cyclin D1 Tg mice, whereas overexpression of Cav-1 caused reversion of this phenotype. Most importantly, Cav-1-/- mammary stromal cells (fat pads) promoted the growth of both normal mammary ductal epithelia and mammary tumor cells. Thus, Cav-1 expression in both epithelial and stromal cells provides a protective effect against mammary hyperplasia as well as mammary tumorigenesis.
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Affiliation(s)
- Terence M Williams
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
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99
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Shakirova Y, Bonnevier J, Albinsson S, Adner M, Rippe B, Broman J, Arner A, Swärd K. Increased Rho activation and PKC-mediated smooth muscle contractility in the absence of caveolin-1. Am J Physiol Cell Physiol 2006; 291:C1326-35. [PMID: 17102036 DOI: 10.1152/ajpcell.00046.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Caveolae are omega-shaped membrane invaginations that are abundant in smooth muscle cells. Since many receptors and signaling proteins co-localize with caveolae, these have been proposed to integrate important signaling pathways. The aim of this study was to test whether RhoA/Rho-kinase and protein kinase C (PKC)-mediated Ca2+sensitization depends on caveolae using caveolin (Cav)-1-deficient (KO) and wild-type (WT) mice. In WT smooth muscle, caveolae were detected and Cav-1, -2 and -3 proteins were expressed. Relative mRNA expression levels were ∼15:1:1 for Cav-1, -2, and -3, respectively. Caveolae were absent in KO and reduced levels of Cav-2 and Cav-3 proteins were seen. In intact ileum longitudinal muscle, no differences in the responses to 5-HT or the muscarinic agonist carbachol were found, whereas contraction elicited by endothelin-1 was reduced. Rho activation by GTPγS was increased in KO compared with WT as shown using a pull-down assay. Following α-toxin permeabilization, no difference in Ca2+sensitivity or in Ca2+sensitization was detected. In KO femoral arteries, phorbol 12,13-dibutyrate (PDBu)-induced and PKC-mediated contraction was increased. This was associated with increased α1-adrenergic contraction. Following inhibition of PKC, α1-adrenergic contraction was normalized. PDBu-induced Ca2+sensitization was not increased in permeabilized femoral arteries. In conclusion, Rho activation, but not Ca2+sensitization, depends on caveolae in the ileum. Moreover, PKC driven arterial contraction is increased in the absence of caveolin-1. This depends on an intact plasma membrane and is not associated with altered Ca2+sensitivity.
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Affiliation(s)
- Yulia Shakirova
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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100
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Kalia M, Kumari S, Chadda R, Hill MM, Parton RG, Mayor S. Arf6-independent GPI-anchored protein-enriched early endosomal compartments fuse with sorting endosomes via a Rab5/phosphatidylinositol-3'-kinase-dependent machinery. Mol Biol Cell 2006; 17:3689-704. [PMID: 16760436 PMCID: PMC1525230 DOI: 10.1091/mbc.e05-10-0980] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In the process of internalization of molecules from the extracellular milieu, a cell uses multiple endocytic pathways, consequently generating different endocytic vesicles. These primary endocytic vesicles are targeted to specific destinations inside the cell. Here, we show that GPI-anchored proteins are internalized by an Arf6-independent mechanism into GPI-anchored protein-enriched early endosomal compartments (GEECs). Internalized GPI-anchored proteins and the fluid phase are first visualized in GEECs that are acidic, primary endocytic structures, negative for early endosomal markers, Rab4, Rab5, and early endosome antigen (EEA)1. They subsequently acquire Rab5 and EEA1 before homotypic fusion with other GEECs, and heterotypic fusion with endosomes containing cargo from the clathrin-dependent endocytic pathway. Although, the formation of GEECs is unaffected by inhibition of Rab5 GTPase and phosphatidylinositol-3'-kinase (PI3K) activity, their fusion with sorting endosomes is dependent on both activities. Overexpression of Rab5 reverts PI3K inhibition of fusion, providing evidence that Rab5 effectors play important roles in heterotypic fusion between the dynamin-independent GEECs and clathrin- and dynamin-dependent sorting endosomes.
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Affiliation(s)
- Manjula Kalia
- *National Centre for Biological Sciences, UAS-GKVK Campus, Bangalore 560065, India; and
| | - Sudha Kumari
- *National Centre for Biological Sciences, UAS-GKVK Campus, Bangalore 560065, India; and
| | - Rahul Chadda
- *National Centre for Biological Sciences, UAS-GKVK Campus, Bangalore 560065, India; and
| | - Michelle M. Hill
- Institute for Molecular Bioscience, University of Queensland, Queensland 4072, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, University of Queensland, Queensland 4072, Australia
| | - Satyajit Mayor
- *National Centre for Biological Sciences, UAS-GKVK Campus, Bangalore 560065, India; and
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