401
|
Tang JC, Liu JH, Liu XL, Liang X, Cai XJ. Effect of fibulin-5 on adhesion, migration and invasion of hepatocellular carcinoma cells via an integrin-dependent mechanism. World J Gastroenterol 2015; 21:11127-11140. [PMID: 26494967 PMCID: PMC4607910 DOI: 10.3748/wjg.v21.i39.11127] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/08/2015] [Accepted: 08/31/2015] [Indexed: 02/06/2023] Open
Abstract
AIM: To elucidate the role of fibulin-5 (FBLN-5) as a suppressor of hepatocellular carcinoma (HCC) cell metastasis via integrin.
METHODS: The expression of FBLN-5 was determined by immunohistochemistry in 140 HCC samples and matched normal tissues, and was further confirmed by RT-PCR and Western blot analyses in various cell lines. Recombinant FBLN-5 was expressed in Escherichia coli BL21(DE3), purified and used in cell attachment assays. Expression of a specific plasmid or a specific siRNA in HCC cells resulted in the overexpression or knockdown of FBLN-5, respectively. Further, the migration and invasion of HCC cells were investigated using the Boyden chamber and transwell assays. The concentration of secreted matrix metalloproteinase 7 (MMP-7) was determined using ELISA.
RESULTS: FBLN-5 expression was found to be downregulated in HCC. Its expression was significantly correlated with advanced tumor metastasis; this was indicative of poor 5-year overall survival. Recombinant full-length human FBLN-5 promoted the attachment of HCC cells via integrins: it inhibited HCC cell adhesion and migration to fibronectin in a concentration-dependent manner. It also inhibited HCC cell migration and invasion through an integrin-binding arginine-glycine-aspartic acid (RGD) motif by downregulating MMP-7.
CONCLUSION: These results suggest that lower FBLN-5 expression is an important indicator of poor survival and that FBLN-5 inhibits HCC motility via an integrin-dependent mechanism. RGD-dependent suppression of MMP-7 by FBLN-5 might contribute to the development of new therapeutic strategies for HCC.
Collapse
|
402
|
Integrin endosomal signalling suppresses anoikis. Nat Cell Biol 2015; 17:1412-21. [PMID: 26436690 DOI: 10.1038/ncb3250] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 09/02/2015] [Indexed: 12/13/2022]
Abstract
Integrin-containing focal adhesions transmit extracellular signals across the plasma membrane to modulate cell adhesion, signalling and survival. Although integrins are known to undergo continuous endo/exocytic traffic, the potential impact of endocytic traffic on integrin-induced signals is unknown. Here, we demonstrate that integrin signalling is not restricted to cell-ECM adhesions and identify an endosomal signalling platform that supports integrin signalling away from the plasma membrane. We show that active focal adhesion kinase (FAK), an established marker of integrin-ECM downstream signalling, localizes with active integrins on endosomes. Integrin endocytosis positively regulates adhesion-induced FAK activation, which is early endosome antigen-1 and small GTPase Rab21 dependent. FAK binds directly to purified endosomes and becomes activated on them, suggesting a role for endocytosis in enhancing distinct integrin downstream signalling events. Finally, endosomal integrin signalling contributes to cancer-related processes such as anoikis resistance, anchorage independence and metastasis.
Collapse
|
403
|
Jack of all trades: functional modularity in the adherens junction. Curr Opin Cell Biol 2015; 36:32-40. [DOI: 10.1016/j.ceb.2015.06.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 05/20/2015] [Accepted: 06/30/2015] [Indexed: 11/22/2022]
|
404
|
Abstract
Mechanical stimuli are known to be potent regulators of the form and function of cells and organisms. Although biological regulation has classically been understood in terms of principles from solution biochemistry, advancements in many fields have led to the development of a suite of techniques that are able to reveal the interplay between mechanical loading and changes in the biochemical properties of proteins in systems ranging from single molecules to living organisms. Here, we review these techniques and highlight the emergence of a new molecular-scale understanding of the mechanisms mediating the detection and response of cells to mechanical stimuli, a process termed mechanotransduction. Specifically, we focus on the role of subcellular adhesion structures in sensing the stiffness of the surrounding environment because this process is pertinent to applications in tissue engineering as well the onset of several mechanosensitive disease states, including cancer.
Collapse
Affiliation(s)
- Andrew S LaCroix
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708;
| | - Katheryn E Rothenberg
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708;
| | - Brenton D Hoffman
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708;
| |
Collapse
|
405
|
Ajeian JN, Horton ER, Astudillo P, Byron A, Askari JA, Millon-Frémillon A, Knight D, Kimber SJ, Humphries MJ, Humphries JD. Proteomic analysis of integrin-associated complexes from mesenchymal stem cells. Proteomics Clin Appl 2015; 10:51-7. [PMID: 26147903 PMCID: PMC4737105 DOI: 10.1002/prca.201500033] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/13/2015] [Accepted: 06/30/2015] [Indexed: 11/10/2022]
Abstract
Purpose Multipotent mesenchymal stem cells (MSCs) have the capability to differentiate down adipocyte, osteocyte and chondrocyte lineages and as such offer a range of potential therapeutic applications. The composition and stiffness of the extracellular matrix (ECM) environment that surrounds cells dictates their transcriptional programme, thereby affecting stem cell lineage decision‐making. Cells sense force via linkages between themselves and their microenvironment, and this is transmitted by integrin receptors and associated adhesion signalling complexes. To identify regulators of MSC force sensing, we sought to catalogue MSC integrin‐associated adhesion complex composition. Experimental design Adhesion complexes formed by MSCs plated on the ECM ligand fibronectin were isolated and characterised by MS. Identified proteins were interrogated by comparison to a literature‐based reference set of cell adhesion‐related components and using ontological and protein–protein interaction network analyses. Results Adhesion complex‐specific proteins in MSCs were identified that comprised predominantly cell adhesion‐related adaptors and actin cytoskeleton regulators. Furthermore, LIM domain‐containing proteins in MSC adhesion complexes were highlighted, which may act as force‐sensing components. Conclusion and clinical relevance These data provide a valuable resource of information regarding the molecular connections that link integrins and adhesion signalling in MSCs, and as such may present novel opportunities for therapeutic intervention.
Collapse
Affiliation(s)
- Jila N Ajeian
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Edward R Horton
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Pablo Astudillo
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Adam Byron
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Janet A Askari
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Angélique Millon-Frémillon
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - David Knight
- Biological Mass Spectrometry Core Facility, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Susan J Kimber
- North West Embryonic Stem Cell Centre, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Martin J Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Jonathan D Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, UK
| |
Collapse
|
406
|
Morishita Y, Tsutsumi K, Ohta Y. Phosphorylation of Serine 402 Regulates RacGAP Protein Activity of FilGAP Protein. J Biol Chem 2015; 290:26328-38. [PMID: 26359494 DOI: 10.1074/jbc.m115.666875] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Indexed: 11/06/2022] Open
Abstract
FilGAP is a Rho GTPase-activating protein (GAP) that specifically regulates Rac. FilGAP is phosphorylated by ROCK, and this phosphorylation stimulates its RacGAP activity. However, it is unclear how phosphorylation regulates cellular functions and localization of FilGAP. We found that non-phosphorylatable FilGAP (ST/A) mutant is predominantly localized to the cytoskeleton along actin filaments and partially co-localized with vinculin around cell periphery, whereas phosphomimetic FilGAP (ST/D) mutant is diffusely cytoplasmic. Moreover, phosphorylated FilGAP detected by Phos-tag is also mainly localized in the cytoplasm. Of the six potential phosphorylation sites in FilGAP tested, only mutation of serine 402 to alanine (S402A) resulted in decreased cell spreading on fibronectin. FilGAP phosphorylated at Ser-402 is localized to the cytoplasm but not at the cytoskeleton. Although Ser-402 is highly phosphorylated in serum-starved quiescent cells, dephosphorylation of Ser-402 is accompanied with the cell spreading on fibronectin. Treatment of the cells expressing wild-type FilGAP with calyculin A, a Ser/Thr phosphatase inhibitor, suppressed cell spreading on fibronectin, whereas cells transfected with FilGAP S402A mutant were not affected by calyculin A. Expression of constitutively activate Arf6 Q67L mutant stimulated membrane blebbing activity of both non-phosphorylatable (ST/A) and phosphomimetic (ST/D) FilGAP mutants. Conversely, depletion of endogenous Arf6 suppressed membrane blebbing induced by FilGAP (ST/A) and (ST/D) mutants. Our study suggests that Arf6 and phosphorylation of FilGAP may regulate FilGAP, and phosphorylation of Ser-402 may play a role in the regulation of cell spreading on fibronectin.
Collapse
Affiliation(s)
- Yuji Morishita
- From the Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, 1-15-1 Kitasato, Sagamihara, Minami-ku, Kanagawa 252-0373, Japan
| | - Koji Tsutsumi
- From the Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, 1-15-1 Kitasato, Sagamihara, Minami-ku, Kanagawa 252-0373, Japan
| | - Yasutaka Ohta
- From the Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, 1-15-1 Kitasato, Sagamihara, Minami-ku, Kanagawa 252-0373, Japan
| |
Collapse
|
407
|
Kowalewski JM, Shafqat-Abbasi H, Jafari-Mamaghani M, Endrias Ganebo B, Gong X, Strömblad S, Lock JG. Disentangling Membrane Dynamics and Cell Migration; Differential Influences of F-actin and Cell-Matrix Adhesions. PLoS One 2015; 10:e0135204. [PMID: 26248038 PMCID: PMC4527765 DOI: 10.1371/journal.pone.0135204] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 07/19/2015] [Indexed: 12/05/2022] Open
Abstract
Cell migration is heavily interconnected with plasma membrane protrusion and retraction (collectively termed “membrane dynamics”). This makes it difficult to distinguish regulatory mechanisms that differentially influence migration and membrane dynamics. Yet such distinctions may be valuable given evidence that cancer cell invasion in 3D may be better predicted by 2D membrane dynamics than by 2D cell migration, implying a degree of functional independence between these processes. Here, we applied multi-scale single cell imaging and a systematic statistical approach to disentangle regulatory associations underlying either migration or membrane dynamics. This revealed preferential correlations between membrane dynamics and F-actin features, contrasting with an enrichment of links between cell migration and adhesion complex properties. These correlative linkages were often non-linear and therefore context-dependent, strengthening or weakening with spontaneous heterogeneity in cell behavior. More broadly, we observed that slow moving cells tend to increase in area, while fast moving cells tend to shrink, and that the size of dynamic membrane domains is independent of cell area. Overall, we define macromolecular features preferentially associated with either cell migration or membrane dynamics, enabling more specific interrogation and targeting of these processes in future.
Collapse
Affiliation(s)
- Jacob M. Kowalewski
- Karolinska Institutet, Department of Biosciences and Nutrition, Huddinge, Sweden
| | | | - Mehrdad Jafari-Mamaghani
- Karolinska Institutet, Department of Biosciences and Nutrition, Huddinge, Sweden
- Division of Mathematical Statistics, Department of Mathematics, Stockholm University, Stockholm, Sweden
| | | | - Xiaowei Gong
- Karolinska Institutet, Department of Biosciences and Nutrition, Huddinge, Sweden
| | - Staffan Strömblad
- Karolinska Institutet, Department of Biosciences and Nutrition, Huddinge, Sweden
| | - John G. Lock
- Karolinska Institutet, Department of Biosciences and Nutrition, Huddinge, Sweden
- * E-mail:
| |
Collapse
|
408
|
Iwamoto DV, Calderwood DA. Regulation of integrin-mediated adhesions. Curr Opin Cell Biol 2015; 36:41-7. [PMID: 26189062 DOI: 10.1016/j.ceb.2015.06.009] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/01/2015] [Accepted: 06/30/2015] [Indexed: 11/18/2022]
Abstract
Integrins are heterodimeric transmembrane adhesion receptors that couple the actin cytoskeleton to the extracellular environment and bidirectionally relay signals across the cell membrane. These processes are critical for cell attachment, migration, differentiation, and survival, and therefore play essential roles in metazoan development, physiology, and pathology. Integrin-mediated adhesions are regulated by diverse factors, including the conformation-specific affinities of integrin receptors for their extracellular ligands, the clustering of integrins and their intracellular binding partners into discrete adhesive structures, mechanical forces exerted on the adhesion, and the intracellular trafficking of integrins themselves. Recent advances shed light onto how the interaction of specific intracellular proteins with the short cytoplasmic tails of integrins controls each of these activities.
Collapse
Affiliation(s)
- Daniel V Iwamoto
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA
| | - David A Calderwood
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA; Department of Cell Biology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA.
| |
Collapse
|
409
|
Liu Y, Mei L, Yu Q, Zhang Q, Gao H, Zhang Z, He Q. Integrin αvβ3 targeting activity study of different retro-inverso sequences of RGD and their potentiality in the designing of tumor targeting peptides. Amino Acids 2015; 47:2533-9. [DOI: 10.1007/s00726-015-2043-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 07/01/2015] [Indexed: 01/01/2023]
|
410
|
A plastic relationship between vinculin-mediated tension and adhesion complex area defines adhesion size and lifetime. Nat Commun 2015; 6:7524. [PMID: 26109125 PMCID: PMC4491829 DOI: 10.1038/ncomms8524] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 05/16/2015] [Indexed: 01/08/2023] Open
Abstract
Cell-matrix adhesions are central mediators of mechanotransduction, yet the interplay between force and adhesion regulation remains unclear. Here we use live cell imaging to map time-dependent cross-correlations between vinculin-mediated tension and adhesion complex area, revealing a plastic, context-dependent relationship. Interestingly, while an expected positive cross-correlation dominated in mid-sized adhesions, small and large adhesions display negative cross-correlation. Furthermore, although large changes in adhesion complex area follow vinculin-mediated tension alterations, small increases in area precede vinculin-mediated tension dynamics. Modelling based on this mapping of the vinculin-mediated tension-adhesion complex area relationship confirms its biological validity, and indicates that this relationship explains adhesion size and lifetime limits, keeping adhesions focal and transient. We also identify a subpopulation of steady-state adhesions whose size and vinculin-mediated tension become stabilized, and whose disassembly may be selectively microtubule-mediated. In conclusion, we define a plastic relationship between vinculin-mediated tension and adhesion complex area that controls fundamental cell-matrix adhesion properties. Cell-matrix adhesions may increase or decrease in size in response to tension; however, the factors determining which of these responses predominates remain unclear. Hernández-Varas et al. quantify the plastic relationship between adhesion size and tension and use modelling to explain this behaviour.
Collapse
|
411
|
Has C, Nyström A. Epidermal Basement Membrane in Health and Disease. CURRENT TOPICS IN MEMBRANES 2015; 76:117-70. [PMID: 26610913 DOI: 10.1016/bs.ctm.2015.05.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Skin, as the organ protecting the individual from environmental aggressions, constantly meets external insults and is dependent on mechanical toughness for its preserved function. Accordingly, the epidermal basement membrane (BM) zone has adapted to enforce tissue integrity. It harbors anchoring structures created through unique organization of common BM components and expression of proteins exclusive to the epidermal BM zone. Evidence for the importance of its correct assembly and the nonredundancy of its components for skin integrity is apparent from the multiple skin blistering disorders caused by mutations in genes coding for proteins associated with the epidermal BM and from autoimmune disorders in which autoantibodies target these molecules. However, it has become clear that these proteins not only provide mechanical support but are also critically involved in tissue homeostasis, repair, and regeneration. In this chapter, we provide an overview of the unique organization and components of the epidermal BM. A special focus will be given to its function during regeneration, and in inherited and acquired diseases.
Collapse
Affiliation(s)
- Cristina Has
- Department of Dermatology, University Medical Center Freiburg, Freiburg, Germany
| | - Alexander Nyström
- Department of Dermatology, University Medical Center Freiburg, Freiburg, Germany
| |
Collapse
|
412
|
Hue I, Evain-Brion D, Fournier T, Degrelle SA. Primary Bovine Extra-Embryonic Cultured Cells: A New Resource for the Study of In Vivo Peri-Implanting Phenotypes and Mesoderm Formation. PLoS One 2015; 10:e0127330. [PMID: 26070137 PMCID: PMC4466545 DOI: 10.1371/journal.pone.0127330] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 04/13/2015] [Indexed: 01/11/2023] Open
Abstract
In addition to nourishing the embryo, extra-embryonic tissues (EETs) contribute to early embryonic patterning, primitive hematopoiesis, and fetal health. These tissues are of major importance for human medicine, as well as for efforts to improve livestock efficiency, but they remain incompletely understood. In bovines, EETs are accessible easily, in large amounts, and prior to implantation. We took advantage of this system to describe, in vitro and in vivo, the cell types present in bovine EETs at Day 18 of development. Specifically, we characterized the gene expression patterns and phenotypes of bovine extra-embryonic ectoderm (or trophoblast; bTC), endoderm (bXEC), and mesoderm (bXMC) cells in culture and compared them to their respective in vivo micro-dissected cells. After a week of culture, certain characteristics (e.g., gene expression) of the in vitro cells were altered with respect to the in vivo cells, but we were able to identify "cores" of cell-type-specific (and substrate-independent) genes that were shared between in vitro and in vivo samples. In addition, many cellular phenotypes were cell-type-specific with regard to extracellular adhesion. We evaluated the ability of individual bXMCs to migrate and spread on micro-patterns, and observed that they easily adapted to diverse environments, similar to in vivo EE mesoderm cells, which encounter different EE epithelia to form chorion, yolk sac, and allantois. With these tissue interactions, different functions arose that were detected in silico and corroborated in vivo at D21-D25. Moreover, analysis of bXMCs allowed us to identify the EE cell ring surrounding the embryonic disc (ED) at D14-15 as mesoderm cells, which had been hypothesized but not shown prior to this study. We envision these data will serve as a major resource for the future in the analysis of peri-implanting phenotypes in response to the maternal metabolism and contribute to subsequent studies of placental/fetal development in eutherians.
Collapse
Affiliation(s)
- Isabelle Hue
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
| | - Danièle Evain-Brion
- INSERM, UMR-S1139, U767, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; PremUp Foundation, Paris, France
| | - Thierry Fournier
- INSERM, UMR-S1139, U767, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Séverine A Degrelle
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France; INSERM, UMR-S1139, U767, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; PremUp Foundation, Paris, France
| |
Collapse
|
413
|
Mócsai A, Walzog B, Lowell CA. Intracellular signalling during neutrophil recruitment. Cardiovasc Res 2015; 107:373-85. [PMID: 25998986 PMCID: PMC4502828 DOI: 10.1093/cvr/cvv159] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 05/19/2015] [Indexed: 12/29/2022] Open
Abstract
Recruitment of leucocytes such as neutrophils to the extravascular space is a critical step of the inflammation process and plays a major role in the development of various diseases including several cardiovascular diseases. Neutrophils themselves play a very active role in that process by sensing their environment and responding to the extracellular cues by adhesion and de-adhesion, cellular shape changes, chemotactic migration, and other effector functions of cell activation. Those responses are co-ordinated by a number of cell surface receptors and their complex intracellular signal transduction pathways. Here, we review neutrophil signal transduction processes critical for recruitment to the site of inflammation. The two key requirements for neutrophil recruitment are the establishment of appropriate chemoattractant gradients and the intrinsic ability of the cells to migrate along those gradients. We will first discuss signalling steps required for sensing extracellular chemoattractants such as chemokines and lipid mediators and the processes (e.g. PI3-kinase pathways) leading to the translation of extracellular chemoattractant gradients to polarized cellular responses. We will then discuss signal transduction by leucocyte adhesion receptors (e.g. tyrosine kinase pathways) which are critical for adhesion to, and migration through the vessel wall. Finally, additional neutrophil signalling pathways with an indirect effect on the neutrophil recruitment process, e.g. through modulation of the inflammatory environment, will be discussed. Mechanistic understanding of these pathways provide better understanding of the inflammation process and may point to novel therapeutic strategies for controlling excessive inflammation during infection or tissue damage.
Collapse
Affiliation(s)
- Attila Mócsai
- Department of Physiology, Semmelweis University School of Medicine, Tűzoltó utca 37-47, 1094 Budapest, Hungary MTA-SE 'Lendület' Inflammation Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, 1094 Budapest, Hungary
| | - Barbara Walzog
- Department of Cardiovascular Physiology and Pathophysiology, Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Clifford A Lowell
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| |
Collapse
|
414
|
Zhong X, Drgonova J, Li CY, Uhl GR. Human cell adhesion molecules: annotated functional subtypes and overrepresentation of addiction-associated genes. Ann N Y Acad Sci 2015; 1349:83-95. [PMID: 25988664 DOI: 10.1111/nyas.12776] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Human cell adhesion molecules (CAMs) are essential for proper development, modulation, and maintenance of interactions between cells and cell-to-cell (and matrix-to-cell) communication about these interactions. Despite the differential functional significance of these roles, there have been surprisingly few systematic studies to enumerate the universe of CAMs and identify specific CAMs in distinct functions. In this paper, we update and review the set of human genes likely to encode CAMs with searches of databases, literature reviews, and annotations. We describe likely CAMs and functional subclasses, including CAMs that have a primary function in information exchange (iCAMs), CAMs involved in focal adhesions, CAM gene products that are preferentially involved with stereotyped and morphologically identifiable connections between cells (e.g., adherens junctions, gap junctions), and smaller numbers of CAM genes in other classes. We discuss a novel proposed mechanism involving selective anchoring of the constituents of iCAM-containing lipid rafts in zones of close neuronal apposition to membranes expressing iCAM binding partners. We also discuss data from genetic and genomic studies of addiction in humans and mouse models to highlight the ways in which CAM variation may contribute to a specific brain-based disorder such as addiction. Specific examples include changes in CAM mRNA splicing mediated by differences in the addiction-associated splicing regulator RBFOX1/A2BP1 and CAM expression in dopamine neurons.
Collapse
Affiliation(s)
- Xiaoming Zhong
- Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Jana Drgonova
- Molecular Neurobiology, NIH-IRP (NIDA), Baltimore, Maryland
| | - Chuan-Yun Li
- Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - George R Uhl
- Molecular Neurobiology, NIH-IRP (NIDA), Baltimore, Maryland.,Research Office, New Mexico VA Health Care System, Albuquerque, New Mexico
| |
Collapse
|
415
|
Wei Q, Pohl TLM, Seckinger A, Spatz JP, Cavalcanti-Adam EA. Regulation of integrin and growth factor signaling in biomaterials for osteodifferentiation. Beilstein J Org Chem 2015; 11:773-83. [PMID: 26124879 PMCID: PMC4464188 DOI: 10.3762/bjoc.11.87] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/07/2015] [Indexed: 12/21/2022] Open
Abstract
Stem cells respond to the microenvironment (niche) they are located in. Under natural conditions, the extracellular matrix (ECM) is the essential component the in stem cell niche, in which both integrin ligands and growth factors are important regulators to directly or indirectly modulate the cell behavior. In this review, we summarize the current knowledge about the potential of integrin ligands and growth factors to induce osteogenic differentiation of stem cells, and discuss the signaling pathways that are initiated by both individual and cooperative parameters. The joint effect of integrin ligands and growth factors is highlighted as the multivalent interactions for bone therapy.
Collapse
Affiliation(s)
- Qiang Wei
- Department of Biophysical Chemistry, Institute for Physical Chemistry, University of Heidelberg, INF 253, 69120 Heidelberg, Germany ; Department of New Materials and Biosystems, Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Theresa L M Pohl
- Department of Biophysical Chemistry, Institute for Physical Chemistry, University of Heidelberg, INF 253, 69120 Heidelberg, Germany ; Department of New Materials and Biosystems, Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Anja Seckinger
- Department of Internal Medicine V, Oncology, Hematology, and Rheumatology, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Joachim P Spatz
- Department of Biophysical Chemistry, Institute for Physical Chemistry, University of Heidelberg, INF 253, 69120 Heidelberg, Germany ; Department of New Materials and Biosystems, Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Elisabetta A Cavalcanti-Adam
- Department of Biophysical Chemistry, Institute for Physical Chemistry, University of Heidelberg, INF 253, 69120 Heidelberg, Germany ; Department of New Materials and Biosystems, Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
| |
Collapse
|
416
|
Yang C, Zhang X, Guo Y, Meng F, Sachs F, Guo J. Mechanical dynamics in live cells and fluorescence-based force/tension sensors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1889-904. [PMID: 25958335 DOI: 10.1016/j.bbamcr.2015.05.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 04/07/2015] [Accepted: 05/01/2015] [Indexed: 01/13/2023]
Abstract
Three signaling systems play the fundamental roles in modulating cell activities: chemical, electrical, and mechanical. While the former two are well studied, the mechanical signaling system is still elusive because of the lack of methods to measure structural forces in real time at cellular and subcellular levels. Indeed, almost all biological processes are responsive to modulation by mechanical forces that trigger dispersive downstream electrical and biochemical pathways. Communication among the three systems is essential to make cells and tissues receptive to environmental changes. Cells have evolved many sophisticated mechanisms for the generation, perception and transduction of mechanical forces, including motor proteins and mechanosensors. In this review, we introduce some background information about mechanical dynamics in live cells, including the ubiquitous mechanical activity, various types of mechanical stimuli exerted on cells and the different mechanosensors. We also summarize recent results obtained using genetically encoded FRET (fluorescence resonance energy transfer)-based force/tension sensors; a new technique used to measure mechanical forces in structural proteins. The sensors have been incorporated into many specific structural proteins and have measured the force gradients in real time within live cells, tissues, and animals.
Collapse
Affiliation(s)
- Chao Yang
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing 210029, PR China
| | - Xiaohan Zhang
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing 210029, PR China
| | - Yichen Guo
- The University of Alabama, Tuscaloosa, AL, 35401, USA
| | - Fanjie Meng
- Physiology and Biophysics Department, Center for Single Molecule Studies, University at Buffalo, The State University of New York at Buffalo, Buffalo, NY, 14214, USA
| | - Frederick Sachs
- Physiology and Biophysics Department, Center for Single Molecule Studies, University at Buffalo, The State University of New York at Buffalo, Buffalo, NY, 14214, USA
| | - Jun Guo
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing 210029, PR China.
| |
Collapse
|
417
|
Hu S, Tee YH, Kabla A, Zaidel-Bar R, Bershadsky A, Hersen P. Structured illumination microscopy reveals focal adhesions are composed of linear subunits. Cytoskeleton (Hoboken) 2015; 72:235-45. [PMID: 26012525 DOI: 10.1002/cm.21223] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 04/14/2015] [Accepted: 05/08/2015] [Indexed: 12/25/2022]
Abstract
The ability to mechanically interact with the extracellular matrix is a fundamental feature of adherent eukaryotic cells. Cell-matrix adhesion in many cell types is mediated by protein complexes called focal adhesions (FAs). Recent progress in super resolution microscopy revealed FAs possess an internal organization, yet such methods do not enable observation of the formation and dynamics of their internal structure in living cells. Here, we combine structured illumination microscopy (SIM) with total internal reflection fluorescence microscopy (TIRF) to show that the proteins inside FA patches are distributed along elongated subunits, typically 300 ± 100 nm wide, separated by 400 ± 100 nm, and individually connected to actin cables. We further show that the formation and dynamics of these linear subunits are intimately linked to radial actin fiber formation and actomyosin contractility. We found FA growth to be the result of nucleation of new linear subunits and their coordinated elongation. Taken together, this study reveals that the basic units of mature focal adhesion are 300-nm-wide elongated, dynamic structures. We anticipate this ultrastructure to be relevant to investigation of the function of FAs and their behavior in response to mechanical stress.
Collapse
Affiliation(s)
- Shiqiong Hu
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Yee-Han Tee
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Alexandre Kabla
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
- Engineering Department, Cambridge University, Trumpington Street, Cambridge, CB2 1PZ, UK
| | - Ronen Zaidel-Bar
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Alexander Bershadsky
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Pascal Hersen
- The Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
- Laboratoire Matière et Systèmes Complexes, UMR 7057 CNRS and Université Paris Diderot, 10 Rue Alice Domon et Léonie Duquet, Paris, 75013, France
| |
Collapse
|
418
|
Mehrban N, Zhu B, Tamagnini F, Young FI, Wasmuth A, Hudson KL, Thomson AR, Birchall MA, Randall AD, Song B, Woolfson DN. Functionalized α-Helical Peptide Hydrogels for Neural Tissue Engineering. ACS Biomater Sci Eng 2015; 1:431-439. [PMID: 26240838 PMCID: PMC4517957 DOI: 10.1021/acsbiomaterials.5b00051] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/28/2015] [Indexed: 12/31/2022]
Abstract
![]()
Trauma to the central and peripheral
nervous systems often lead
to serious morbidity. Current surgical methods for repairing or replacing
such damage have limitations. Tissue engineering offers a potential
alternative. Here we show that functionalized α-helical-peptide
hydrogels can be used to induce attachment, migration, proliferation
and differentiation of murine embryonic neural stem cells (NSCs).
Specifically, compared with undecorated gels, those functionalized
with Arg-Gly-Asp-Ser (RGDS) peptides increase the proliferative activity
of NSCs; promote their directional migration; induce differentiation,
with increased expression of microtubule-associated protein-2, and
a low expression of glial fibrillary acidic protein; and lead to the
formation of larger neurospheres. Electrophysiological measurements
from NSCs grown in RGDS-decorated gels indicate developmental progress
toward mature neuron-like behavior. Our data indicate that these functional
peptide hydrogels may go some way toward overcoming the limitations
of current approaches to nerve-tissue repair.
Collapse
Affiliation(s)
- Nazia Mehrban
- School of Chemistry, University of Bristol , Bristol BS8 1TS, United Kingdom
| | - Bangfu Zhu
- School of Dentistry, Cardiff University , Cardiff CF10 3XQ, United Kingdom
| | | | - Fraser I Young
- School of Dentistry, Cardiff University , Cardiff CF10 3XQ, United Kingdom
| | - Alexandra Wasmuth
- School of Chemistry, University of Bristol , Bristol BS8 1TS, United Kingdom
| | - Kieran L Hudson
- School of Chemistry, University of Bristol , Bristol BS8 1TS, United Kingdom
| | - Andrew R Thomson
- School of Chemistry, University of Bristol , Bristol BS8 1TS, United Kingdom
| | - Martin A Birchall
- University College London Ear Institute , London WC1X 8DA, United Kingdom
| | - Andrew D Randall
- Medical School, University of Exeter , Exeter EX4 4PS, United Kingdom
| | - Bing Song
- School of Dentistry, Cardiff University , Cardiff CF10 3XQ, United Kingdom
| | - Derek N Woolfson
- School of Chemistry, University of Bristol , Bristol BS8 1TS, United Kingdom ; School of Biochemistry, University of Bristol , Bristol BS8 1TD, United Kingdom ; BrisSynBio, University of Bristol , Bristol BS8 1TQ, United Kingdom
| |
Collapse
|
419
|
Zienert E, Eke I, Aust D, Cordes N. LIM-only protein FHL2 critically determines survival and radioresistance of pancreatic cancer cells. Cancer Lett 2015; 364:17-24. [PMID: 25917075 DOI: 10.1016/j.canlet.2015.04.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 04/17/2015] [Accepted: 04/19/2015] [Indexed: 11/27/2022]
Abstract
Numerous factors determine the current poor prognosis of pancreatic ductal adenocarcinoma (PDAC). One of the greatest challenges to overcome is treatment resistance. Among a large repertoire of intrinsic resistance mechanisms, integrin-mediated cell adhesion to extracellular matrix (ECM) has been identified to be fundamental. Coalesced in focal adhesion complexes, integrins, receptor tyrosine kinases, protein kinases and adapter proteins mediate prosurvival signaling. Four and a half LIM domains protein 2 (FHL2) is one of these adapter proteins, which operates through protein-protein interactions and shows tumor-specific expression. Based on this, we investigated FHL2 expression in PDAC specimens and three-dimensionally grown cell lines and how FHL2 mechanistically contributes to cell survival, cell cycling and radiation resistance. PDAC exhibited a significantly increased and heterogeneous FHL2 expression. Upon FHL2 depletion, pancreatic cancer cell lines showed significantly decreased cell survival, proliferation and radioresistance as well as enhanced apoptosis and MEK/ERK signaling and cyclin D1, E, A and B1 expression were strongly induced. Targeting of FHL2 and MEK1 was similarly effective than FHL2 depletion alone, suggesting MEK1 as a downstream signaling mediator of FHL2. Taken together, our results provide evidence for the importance of the focal adhesion protein FHL2 in pancreatic cancer cell survival, proliferation and radiosensitivity.
Collapse
Affiliation(s)
- Elisa Zienert
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Iris Eke
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Daniela Aust
- Institute for Pathology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Nils Cordes
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; Institute of Radiooncology, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany; Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; German Cancer Consortium (DKTK), 01307 Dresden, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany.
| |
Collapse
|
420
|
Huveneers S, Daemen MJAP, Hordijk PL. Between Rho(k) and a hard place: the relation between vessel wall stiffness, endothelial contractility, and cardiovascular disease. Circ Res 2015; 116:895-908. [PMID: 25722443 DOI: 10.1161/circresaha.116.305720] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Vascular stiffness is a mechanical property of the vessel wall that affects blood pressure, permeability, and inflammation. As a result, vascular stiffness is a key driver of (chronic) human disorders, including pulmonary arterial hypertension, kidney disease, and atherosclerosis. Responses of the endothelium to stiffening involve integration of mechanical cues from various sources, including the extracellular matrix, smooth muscle cells, and the forces that derive from shear stress of blood. This response in turn affects endothelial cell contractility, which is an important property that regulates endothelial stiffness, permeability, and leukocyte-vessel wall interactions. Moreover, endothelial stiffening reduces nitric oxide production, which promotes smooth muscle cell contraction and vasoconstriction. In fact, vessel wall stiffening, and microcirculatory endothelial dysfunction, precedes hypertension and thus underlies the development of vascular disease. Here, we review the cross talk among vessel wall stiffening, endothelial contractility, and vascular disease, which is controlled by Rho-driven actomyosin contractility and cellular mechanotransduction. In addition to discussing the various inputs and relevant molecular events in the endothelium, we address which actomyosin-regulated changes at cell adhesion complexes are genetically associated with human cardiovascular disease. Finally, we discuss recent findings that broaden therapeutic options for targeting this important mechanical signaling pathway in vascular pathogenesis.
Collapse
Affiliation(s)
- Stephan Huveneers
- From the Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Swammerdam Institute for Life Sciences (S.H., P.L.H.) and Department of Pathology (M.J.A.P.D.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
| | - Mat J A P Daemen
- From the Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Swammerdam Institute for Life Sciences (S.H., P.L.H.) and Department of Pathology (M.J.A.P.D.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Peter L Hordijk
- From the Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Swammerdam Institute for Life Sciences (S.H., P.L.H.) and Department of Pathology (M.J.A.P.D.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
421
|
Sharma S, Patnaik SK, Taggart RT, Kannisto ED, Enriquez SM, Gollnick P, Baysal BE. APOBEC3A cytidine deaminase induces RNA editing in monocytes and macrophages. Nat Commun 2015; 6:6881. [PMID: 25898173 PMCID: PMC4411297 DOI: 10.1038/ncomms7881] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 03/10/2015] [Indexed: 01/01/2023] Open
Abstract
The extent, regulation and enzymatic basis of RNA editing by cytidine deamination are incompletely understood. Here we show that transcripts of hundreds of genes undergo site-specific C>U RNA editing in macrophages during M1 polarization and in monocytes in response to hypoxia and interferons. This editing alters the amino acid sequences for scores of proteins, including many that are involved in pathogenesis of viral diseases. APOBEC3A, which is known to deaminate cytidines of single-stranded DNA and to inhibit viruses and retrotransposons, mediates this RNA editing. Amino acid residues of APOBEC3A that are known to be required for its DNA deamination and anti-retrotransposition activities were also found to affect its RNA deamination activity. Our study demonstrates the cellular RNA editing activity of a member of the APOBEC3 family of innate restriction factors and expands the understanding of C>U RNA editing in mammals. Aberrant RNA editing is linked to a range of neuropsychiatric and chronic diseases. Here Sharma et al. show that APOBEC3A can function as an RNA editing protein in response to physiological stimuli, significantly expanding our understanding of RNA editing and the role this may play in diseases.
Collapse
Affiliation(s)
- Shraddha Sharma
- Department of Pathology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, New York 14203, USA
| | - Santosh K Patnaik
- Department of Thoracic Surgery, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, New York 14203, USA
| | - R Thomas Taggart
- Department of Pathology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, New York 14203, USA
| | - Eric D Kannisto
- Department of Thoracic Surgery, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, New York 14203, USA
| | - Sally M Enriquez
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260, USA
| | - Paul Gollnick
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260, USA
| | - Bora E Baysal
- Department of Pathology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, New York 14203, USA
| |
Collapse
|
422
|
Parker-Manuel RP, Grevelding CG, Gelmedin V. Cryptic 3' mRNA processing signals hinder the expression of Schistosoma mansoni integrins in yeast. Mol Biochem Parasitol 2015; 199:51-7. [PMID: 25827755 DOI: 10.1016/j.molbiopara.2015.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 03/13/2015] [Accepted: 03/19/2015] [Indexed: 11/26/2022]
Abstract
The expression of parasite genes has often proven difficult in heterologous systems such as yeast or E. coli. Most often, promoter choice and codon usage were hypothesised to be the main reason for expression failures. The trematode parasite Schistosoma mansoni has five integrin genes named Smα-Int1-4 and Smβ-Int1, which we aimed to express in the yeast Saccharomyces cerevisiae. This has not been achieved, however, as only Smβ-Int1 integrin could be expressed. When the four α integrins were driven by a stronger promoter, this enabled Smα-Int1 to be expressed as well, but the remaining integrins, Smα-Int2-4, still could not be expressed. Evidence from RT-PCR experiments suggested that this was due to premature transcription termination. Using detailed in silico sequence analyses we identified AT-rich stretches in these integrin genes, which have high similarity to yeast mRNA 3'-end processing signals. We hypothesised that these signals were causing the premature truncation. To test this, we designed an optimised version of Smα-Int3, in which the sequence was modified to replace the yeast 3' processing signals. This strategy allowed us to express Smα-Int3 integrin successfully in S. cerevisiae. These findings show that the misinterpretation of AT-rich sequences by yeast 3'-mRNA processing machinery can cause problems when attempting to express genes containing such sequences in this host.
Collapse
Affiliation(s)
- Richard P Parker-Manuel
- Biomedizinisches Forschungszentrum Seltersberg (BFS), Institut für Parasitologie, Schubertstraße 81, Gießen 35392, Germany
| | - Christoph G Grevelding
- Biomedizinisches Forschungszentrum Seltersberg (BFS), Institut für Parasitologie, Schubertstraße 81, Gießen 35392, Germany
| | - Verena Gelmedin
- Biomedizinisches Forschungszentrum Seltersberg (BFS), Institut für Parasitologie, Schubertstraße 81, Gießen 35392, Germany.
| |
Collapse
|
423
|
Emerging properties of adhesion complexes: what are they and what do they do? Trends Cell Biol 2015; 25:388-97. [PMID: 25824971 DOI: 10.1016/j.tcb.2015.02.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 02/13/2015] [Accepted: 02/24/2015] [Indexed: 02/07/2023]
Abstract
The regulation of cell adhesion machinery is central to a wide variety of developmental and pathological processes and occurs primarily within integrin-associated adhesion complexes. Here, we review recent advances that have furthered our understanding of the composition, organisation, and dynamics of these complexes, and provide an updated view on their emerging functions. Key findings are that adhesion complexes contain both core and non-canonical components. As a result of the dramatic increase in the range of components observed in adhesion complexes by proteomics, we comment on newly emerging functions for adhesion signalling. We conclude that, from a cellular or tissue systems perspective, adhesion signalling should be viewed as an emergent property of both the core and non-canonical adhesion complex components.
Collapse
|
424
|
Yalcin EG, He Y, Orhan D, Pazzagli C, Emiralioglu N, Has C. Crucial role of posttranslational modifications of integrin α3 in interstitial lung disease and nephrotic syndrome. Hum Mol Genet 2015; 24:3679-88. [PMID: 25810266 DOI: 10.1093/hmg/ddv111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/23/2015] [Indexed: 01/06/2023] Open
Abstract
Interstitial lung disease, nephrotic syndrome and junctional epidermolysis bullosa is an autosomal recessive multiorgan disorder caused by mutations in the gene for the integrin α3 subunit (ITGA3). The full spectrum of manifestations and genotype-phenotype correlations is still poorly characterized. Here, we uncovered the disease-causing role and the molecular mechanisms underlying a homozygous ITGA3 mutation leading to the single amino acid substitution, p.R463W. The patient suffered from respiratory distress and episodes of cyanosis with onset in the first week of life and had a nephrotic syndrome. Although there was no clinical evidence for cutaneous fragility, the analysis of a skin sample and of skin epithelial cells enabled the direct assessment of the authentic mutant protein. We show that the mutation altered the conformation of the extracellular β-propeller domain of the integrin α3 subunit preventing correct processing of N-linked oligosaccharides, heterodimerization with β1 integrin and maturation through cleavage into heavy and light chains in the Golgi. Confocal microscopy demonstrated that the mutant protein accumulated intracellularly, but it was not present in focal adhesions or on the cell membrane as shown by flow cytometry. These findings highlight that single amino acid changes in the integrin α3 subunit may crucially alter the structure and complex processing of this integrin, completely preventing its functionality. The present report also underscores that ITGA3 mutations may account for atypical cases solely with early onset respiratory and renal involvement.
Collapse
Affiliation(s)
| | - Yinghong He
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany and
| | - Diclehan Orhan
- Department of Pediatric Pathology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Chiara Pazzagli
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany and Spemann Graduate School of Biology and Medicine (SGBM), Albert Ludwigs University Freiburg, Freiburg, Germany
| | | | - Cristina Has
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany and
| |
Collapse
|
425
|
van Roosmalen W, Le Dévédec SE, Golani O, Smid M, Pulyakhina I, Timmermans AM, Look MP, Zi D, Pont C, de Graauw M, Naffar-Abu-Amara S, Kirsanova C, Rustici G, Hoen PAC', Martens JWM, Foekens JA, Geiger B, van de Water B. Tumor cell migration screen identifies SRPK1 as breast cancer metastasis determinant. J Clin Invest 2015; 125:1648-64. [PMID: 25774502 DOI: 10.1172/jci74440] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 01/29/2015] [Indexed: 01/14/2023] Open
Abstract
Tumor cell migration is a key process for cancer cell dissemination and metastasis that is controlled by signal-mediated cytoskeletal and cell matrix adhesion remodeling. Using a phagokinetic track assay with migratory H1299 cells, we performed an siRNA screen of almost 1,500 genes encoding kinases/phosphatases and adhesome- and migration-related proteins to identify genes that affect tumor cell migration speed and persistence. Thirty candidate genes that altered cell migration were validated in live tumor cell migration assays. Eight were associated with metastasis-free survival in breast cancer patients, with integrin β3-binding protein (ITGB3BP), MAP3K8, NIMA-related kinase (NEK2), and SHC-transforming protein 1 (SHC1) being the most predictive. Examination of genes that modulate migration indicated that SRPK1, encoding the splicing factor kinase SRSF protein kinase 1, is relevant to breast cancer outcomes, as it was highly expressed in basal breast cancer. Furthermore, high SRPK1 expression correlated with poor breast cancer disease outcome and preferential metastasis to the lungs and brain. In 2 independent murine models of breast tumor metastasis, stable shRNA-based SRPK1 knockdown suppressed metastasis to distant organs, including lung, liver, and spleen, and inhibited focal adhesion reorganization. Our study provides comprehensive information on the molecular determinants of tumor cell migration and suggests that SRPK1 has potential as a drug target for limiting breast cancer metastasis.
Collapse
|
426
|
Tan CL, Kwok JCF, Heller JPD, Zhao R, Eva R, Fawcett JW. Full length talin stimulates integrin activation and axon regeneration. Mol Cell Neurosci 2015; 68:1-8. [PMID: 25771432 PMCID: PMC4604251 DOI: 10.1016/j.mcn.2015.03.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 03/07/2015] [Accepted: 03/09/2015] [Indexed: 11/19/2022] Open
Abstract
Integrin function is regulated by activation involving conformational changes that modulate ligand-binding affinity and downstream signaling. Activation is regulated through inside-out signaling which is controlled by many signaling pathways via a final common pathway through kindlin and talin, which bind to the intracellular tail of beta integrins. Previous studies have shown that the axon growth inhibitory molecules NogoA and chondroitin sulfate proteoglycans (CSPGs) inactivate integrins. Overexpressing kindlin-1 in dorsal root ganglion (DRG) neurons activates integrins, enabling their axons to overcome inhibitory molecules in the environment, and promoting regeneration in vivo following dorsal root crush. Other studies have indicated that expression of the talin head alone or with kindlin can enhance integrin activation. Here, using adult rat DRG neurons, we investigate the effects of overexpressing various forms of talin on axon growth and integrin signaling. We found that overexpression of the talin head activated axonal integrins but inhibited downstream signaling via FAK, and did not promote axon growth. Similarly, co-expression of the talin head and kindlin-1 prevented the growth-promoting effect of kindlin-1, suggesting that the talin head acts as a form of dominant negative for integrin function. Using full-length talin constructs in PC12 cells we observed that neurite growth was enhanced by the expression of wild-type talin and more so by two ‘activated’ forms of talin produced by point mutation (on laminin and aggrecan–laminin substrates). Nevertheless, co-expression of full-length talin with kindlin did not promote neurite growth more than either molecule alone. In vivo, we find that talin is present in PNS axons (sciatic nerve), and also in CNS axons of the corticospinal tract. Full length talin can activate integrins and stimulate axon regeneration on inhibitory CSPGs. The talin head domain can activate integrins, but acts as a dominant negative for talin function. Talin and kindlins do not have additive effects on axon growth. Talin is transported into the axons of the sciatic nerve and the corticospinal tract.
Collapse
Affiliation(s)
- Chin Lik Tan
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK
| | - Jessica C F Kwok
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK
| | - Janosch P D Heller
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK
| | - Rongrong Zhao
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK
| | - Richard Eva
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK
| | - James W Fawcett
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK.
| |
Collapse
|
427
|
Jones MC, Humphries JD, Byron A, Millon-Frémillon A, Robertson J, Paul NR, Ng DHJ, Askari JA, Humphries MJ. Isolation of integrin-based adhesion complexes. CURRENT PROTOCOLS IN CELL BIOLOGY 2015; 66:9.8.1-9.8.15. [PMID: 25727331 PMCID: PMC4402726 DOI: 10.1002/0471143030.cb0908s66] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The integration of cells with their extracellular environment is facilitated by cell surface adhesion receptors, such as integrins, which play important roles in both normal development and the onset of pathologies. Engagement of integrins with their ligands in the extracellular matrix, or counter-receptors on other cells, initiates the intracellular assembly of a wide variety of proteins into adhesion complexes such as focal contacts, focal adhesions, and fibrillar adhesions. The proteins recruited to these complexes mediate bidirectional signaling across the plasma membrane, and, as such, help to coordinate and/or modulate the multitude of physical and chemical signals to which the cell is subjected. The protocols in this unit describe two approaches for the isolation or enrichment of proteins contained within integrin-associated adhesion complexes, together with their local plasma membrane/cytosolic environments, from cells in culture. In the first protocol, integrin-associated adhesion structures are affinity isolated using microbeads coated with extracellular ligands or antibodies. The second protocol describes the isolation of ventral membrane preparations that are enriched for adhesion complex structures. The protocols permit the determination of adhesion complex components via subsequent downstream analysis by western blotting or mass spectrometry.
Collapse
Affiliation(s)
- Matthew C. Jones
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Jonathan D. Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Adam Byron
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Angelique Millon-Frémillon
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Joseph Robertson
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Nikki R. Paul
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Daniel H. J. Ng
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Janet A. Askari
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Martin J. Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| |
Collapse
|
428
|
Robertson J, Jacquemet G, Byron A, Jones MC, Warwood S, Selley JN, Knight D, Humphries JD, Humphries MJ. Defining the phospho-adhesome through the phosphoproteomic analysis of integrin signalling. Nat Commun 2015; 6:6265. [PMID: 25677187 PMCID: PMC4338609 DOI: 10.1038/ncomms7265] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 01/09/2015] [Indexed: 01/09/2023] Open
Abstract
Cell–extracellular matrix (ECM) adhesion is a fundamental requirement for multicellular existence due to roles in positioning, proliferation and differentiation. Phosphorylation plays a major role in adhesion signalling; however, a full understanding of the phosphorylation events that occur at sites of adhesion is lacking. Here we report a proteomic and phosphoproteomic analysis of adhesion complexes isolated from cells spread on fibronectin. We identify 1,174 proteins, 499 of which are phosphorylated (1,109 phosphorylation sites), including both well-characterized and novel adhesion-regulated phosphorylation events. Immunoblotting suggests that two classes of phosphorylated residues are found at adhesion sites—those induced by adhesion and those constitutively phosphorylated but recruited in response to adhesion. Kinase prediction analysis identifies novel kinases with putative roles in adhesion signalling including CDK1, inhibition of which reduces adhesion complex formation. This phospho-adhesome data set constitutes a valuable resource to improve our understanding of the signalling mechanisms through which cell–ECM interactions control cell behaviour. Protein phosphorylation is known to play an important role in cell adhesion signalling. Robertson et al. present a proteomic resource mapping the phosphorylation states of proteins isolated from adhesion complexes and, taking advantage of this data set, show that the cell cycle kinase CDK1 may influence cell adhesion.
Collapse
Affiliation(s)
- Joseph Robertson
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Guillaume Jacquemet
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Adam Byron
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Matthew C Jones
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Stacey Warwood
- Biological Mass Spectrometry Core Facility, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Julian N Selley
- Biological Mass Spectrometry Core Facility, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - David Knight
- Biological Mass Spectrometry Core Facility, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Jonathan D Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Martin J Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| |
Collapse
|
429
|
A proteomic approach reveals integrin activation state-dependent control of microtubule cortical targeting. Nat Commun 2015; 6:6135. [PMID: 25609142 PMCID: PMC4317495 DOI: 10.1038/ncomms7135] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 12/15/2014] [Indexed: 12/13/2022] Open
Abstract
Integrin activation, which is regulated by allosteric changes in receptor conformation, enables cellular responses to the chemical, mechanical and topological features of the extracellular microenvironment. A global view of how activation state converts the molecular composition of the region proximal to integrins into functional readouts is, however, lacking. Here, using conformation-specific monoclonal antibodies, we report the isolation of integrin activation state-dependent complexes and their characterization by mass spectrometry. Quantitative comparisons, integrating network, clustering, pathway and image analyses, define multiple functional protein modules enriched in a conformation-specific manner. Notably, active integrin complexes are specifically enriched for proteins associated with microtubule-based functions. Visualization of microtubules on micropatterned surfaces and live cell imaging demonstrate that active integrins establish an environment that stabilizes microtubules at the cell periphery. These data provide a resource for the interrogation of the global molecular connections that link integrin activation to adhesion signalling. Integrins are activated by many extracellular cues and respond by assembling diverse signalling complexes. Byron et al. use activation state-specific antibodies to proteomically characterize these complexes, and provide insight into integrin-dependent microtubule stabilization.
Collapse
|
430
|
Viticchiè G, Muller PAJ. c-Met and Other Cell Surface Molecules: Interaction, Activation and Functional Consequences. Biomedicines 2015; 3:46-70. [PMID: 28536399 PMCID: PMC5344229 DOI: 10.3390/biomedicines3010046] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 01/08/2015] [Indexed: 12/18/2022] Open
Abstract
The c-Met receptor, also known as the HGF receptor, is one of the most studied tyrosine kinase receptors, yet its biological functions and activation mechanisms are still not fully understood. c-Met has been implicated in embryonic development and organogenesis, in tissue remodelling homeostasis and repair and in cancer metastasis. These functions are indicative of the many cellular processes in which the receptor plays a role, including cell motility, scattering, survival and proliferation. In the context of malignancy, sustained activation of c-Met leads to a signalling cascade involving a multitude of kinases that initiate an invasive and metastatic program. Many proteins can affect the activation of c-Met, including a variety of other cell surface and membrane-spanning molecules or receptors. Some cell surface molecules share structural homology with the c-Met extracellular domain and can activate c-Met via clustering through this domain (e.g., plexins), whereas other receptor tyrosine kinases can enhance c-Met activation and signalling through intracellular signalling cascades (e.g., EGFR). In this review, we provide an overview of c-Met interactions and crosstalk with partner molecules and the functional consequences of these interactions on c-Met activation and downstream signalling, c-Met intracellular localization/recycling and c-Met degradation.
Collapse
Affiliation(s)
- Giuditta Viticchiè
- MRC (Medical Research Council) Toxicology Unit, Lancaster Road, Leicester LE1 9HN, UK.
| | - Patricia A J Muller
- MRC (Medical Research Council) Toxicology Unit, Lancaster Road, Leicester LE1 9HN, UK.
| |
Collapse
|
431
|
Yu M, Strohmeyer N, Wang J, Müller DJ, Helenius J. Increasing throughput of AFM-based single cell adhesion measurements through multisubstrate surfaces. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2015; 6:157-66. [PMID: 25671160 PMCID: PMC4311671 DOI: 10.3762/bjnano.6.15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 12/10/2014] [Indexed: 05/23/2023]
Abstract
Mammalian cells regulate adhesion by expressing and regulating a diverse array of cell adhesion molecules on their cell surfaces. Since different cell types express distinct sets of cell adhesion molecules, substrate-specific adhesion is cell type- and condition-dependent. Single-cell force spectroscopy is used to quantify the contribution of cell adhesion molecules to adhesion of cells to specific substrates at both the cell and single molecule level. However, the low throughput of single-cell adhesion experiments greatly limits the number of substrates that can be examined. In order to overcome this limitation, segmented polydimethylsiloxane (PDMS) masks were developed, allowing the measurement of cell adhesion to multiple substrates. To verify the utility of the masks, the adhesion of four different cell lines, HeLa (Kyoto), prostate cancer (PC), mouse kidney fibroblast and MDCK, to three extracellular matrix proteins, fibronectin, collagen I and laminin 332, was examined. The adhesion of each cell line to different matrix proteins was found to be distinct; no two cell lines adhered equally to each of the proteins. The PDMS masks improved the throughput limitation of single-cell force spectroscopy and allowed for experiments that previously were not feasible. Since the masks are economical and versatile, they can aid in the improvement of various assays.
Collapse
Affiliation(s)
- Miao Yu
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
- Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Nico Strohmeyer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Jinghe Wang
- Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Daniel J Müller
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Jonne Helenius
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| |
Collapse
|
432
|
Spanjaard E, Smal I, Angelopoulos N, Verlaan I, Matov A, Meijering E, Wessels L, Bos H, de Rooij J. Quantitative imaging of focal adhesion dynamics and their regulation by HGF and Rap1 signaling. Exp Cell Res 2015; 330:382-397. [DOI: 10.1016/j.yexcr.2014.10.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 09/19/2014] [Accepted: 10/12/2014] [Indexed: 01/09/2023]
|
433
|
|
434
|
Microtubule-dependent modulation of adhesion complex composition. PLoS One 2014; 9:e115213. [PMID: 25526367 PMCID: PMC4272306 DOI: 10.1371/journal.pone.0115213] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 11/19/2014] [Indexed: 12/24/2022] Open
Abstract
The microtubule network regulates the turnover of integrin-containing adhesion complexes to stimulate cell migration. Disruption of the microtubule network results in an enlargement of adhesion complex size due to increased RhoA-stimulated actomyosin contractility, and inhibition of adhesion complex turnover; however, the microtubule-dependent changes in adhesion complex composition have not been studied in a global, unbiased manner. Here we used label-free quantitative mass spectrometry-based proteomics to determine adhesion complex changes that occur upon microtubule disruption with nocodazole. Nocodazole-treated cells displayed an increased abundance of the majority of known adhesion complex components, but no change in the levels of the fibronectin-binding α5β1 integrin. Immunofluorescence analyses confirmed these findings, but revealed a change in localisation of adhesion complex components. Specifically, in untreated cells, α5-integrin co-localised with vinculin at peripherally located focal adhesions and with tensin at centrally located fibrillar adhesions. In nocodazole-treated cells, however, α5-integrin was found in both peripherally located and centrally located adhesion complexes that contained both vinculin and tensin, suggesting a switch in the maturation state of adhesion complexes to favour focal adhesions. Moreover, the switch to focal adhesions was confirmed to be force-dependent as inhibition of cell contractility with the Rho-associated protein kinase inhibitor, Y-27632, prevented the nocodazole-induced conversion. These results highlight a complex interplay between the microtubule cytoskeleton, adhesion complex maturation state and intracellular contractile force, and provide a resource for future adhesion signaling studies. The proteomics data have been deposited in the ProteomeXchange with identifier PXD001183.
Collapse
|
435
|
Al Haj A, Mazur AJ, Radaszkiewicz K, Radaszkiewicz T, Makowiecka A, Stopschinski BE, Schönichen A, Geyer M, Mannherz HG. Distribution of formins in cardiac muscle: FHOD1 is a component of intercalated discs and costameres. Eur J Cell Biol 2014; 94:101-13. [PMID: 25555464 DOI: 10.1016/j.ejcb.2014.11.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 11/21/2014] [Accepted: 11/26/2014] [Indexed: 10/24/2022] Open
Abstract
The formin homology domain-containing protein1 (FHOD1) suppresses actin polymerization by inhibiting nucleation, but bundles actin filaments and caps filament barbed ends. Two polyclonal antibodies against FHOD1 were generated against (i) its N-terminal sequence (residues 1-339) and (ii) a peptide corresponding the sequence from position 358-371, which is unique for FHOD1 and does not occur in its close relative FHOD3. After affinity purification both antibodies specifically stain purified full length FHOD1 and a band of similar molecular mass in homogenates of cardiac muscle. The antibody against the N-terminus of FHOD1 was used for immunostaining cells of established lines, primary neonatal (NRC) and adult (ARC) rat cardiomyocytes and demonstrated the presence of FHOD1 in HeLa and fibroblastic cells along stress fibers and within presumed lamellipodia and actin arcs. In NRCs and ARCs we observed a prominent staining of presumed intercalated discs (ICD). Immunostaining of sections of hearts with both anti-FHOD1 antibodies confirmed the presence of FHOD1 in ICDs and double immunostaining demonstrated its colocalisation with cadherin, plakoglobin and a probably slightly shifted localization to connexin43. Similarly, immunostaining of isolated mouse or pig ICDs corroborated the presence of FHOD1 and its colocalisation with the mentioned cell junctional components. Anti-FHOD1 immunoblots of isolated ICDs demonstrated the presence of an immunoreactive band comigrating with purified FHOD1. Conversely, an anti-peptide antibody specific for FHOD3 with no cross-reactivity against FHOD1 immunostained on sections of cardiac muscle and ARCs the myofibrils in a cross-striated pattern but not the ICDs. In addition, the anti-peptide-FHOD1 antibody stained the lateral sarcolemma of ARCs in a banded pattern. Double immunostaining with anti-cadherin and -integrin-ß1 indicated the additional localization of FHOD1 in costameres. Immunostaining of cardiac muscle sections or ARCs with antibodies against mDia3-FH2-domain showed colocalisation with cadherin along the lateral border of cardiomyocytes suggesting also its presence in costameres.
Collapse
Affiliation(s)
- Abdulatif Al Haj
- Department of Anatomy and Molecular Embryology, Ruhr-University, Bochum, Germany
| | - Antonina J Mazur
- Department of Anatomy and Molecular Embryology, Ruhr-University, Bochum, Germany; Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Poland
| | - Katarzyna Radaszkiewicz
- Department of Anatomy and Molecular Embryology, Ruhr-University, Bochum, Germany; Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Poland
| | - Tomasz Radaszkiewicz
- Department of Anatomy and Molecular Embryology, Ruhr-University, Bochum, Germany; Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Poland
| | - Aleksandra Makowiecka
- Department of Anatomy and Molecular Embryology, Ruhr-University, Bochum, Germany; Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Poland
| | - Barbara E Stopschinski
- Department of Anatomy and Molecular Embryology, Ruhr-University, Bochum, Germany; Department of Physical Biochemistry, Max-Planck-Institute of Molecular Physiology, Dortmund, Germany
| | - André Schönichen
- Department of Physical Biochemistry, Max-Planck-Institute of Molecular Physiology, Dortmund, Germany
| | - Matthias Geyer
- Department of Physical Biochemistry, Max-Planck-Institute of Molecular Physiology, Dortmund, Germany; Center of Advanced European Studies and Research (CAESAR), Bonn, Germany
| | - Hans Georg Mannherz
- Department of Anatomy and Molecular Embryology, Ruhr-University, Bochum, Germany.
| |
Collapse
|
436
|
Macek Jilkova Z, Lisowska J, Manet S, Verdier C, Deplano V, Geindreau C, Faurobert E, Albigès-Rizo C, Duperray A. CCM proteins control endothelial β1 integrin dependent response to shear stress. Biol Open 2014; 3:1228-35. [PMID: 25432514 PMCID: PMC4265761 DOI: 10.1242/bio.201410132] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Hemodynamic shear stress from blood flow on the endothelium critically regulates vascular function in many physiological and pathological situations. Endothelial cells adapt to shear stress by remodeling their cytoskeletal components and subsequently by changing their shape and orientation. We demonstrate that β1 integrin activation is critically controlled during the mechanoresponse of endothelial cells to shear stress. Indeed, we show that overexpression of the CCM complex, an inhibitor of β1 integrin activation, blocks endothelial actin rearrangement and cell reorientation in response to shear stress similarly to β1 integrin silencing. Conversely, depletion of CCM2 protein leads to an elongated “shear-stress-like” phenotype even in the absence of flow. Taken together, our findings reveal the existence of a balance between positive extracellular and negative intracellular signals, i.e. shear stress and CCM complex, for the control of β1 integrin activation and subsequent adaptation of vascular endothelial cells to mechanostimulation by fluid shear stress.
Collapse
Affiliation(s)
- Zuzana Macek Jilkova
- INSERM, Institut Albert Bonniot, F-38000 Grenoble, France Université Grenoble Alpes, Institut Albert Bonniot, F-38000 Grenoble, France
| | - Justyna Lisowska
- INSERM, Institut Albert Bonniot, F-38000 Grenoble, France Université Grenoble Alpes, Institut Albert Bonniot, F-38000 Grenoble, France CNRS ERL 5284, F-38042 Grenoble, France
| | - Sandra Manet
- INSERM, Institut Albert Bonniot, F-38000 Grenoble, France Université Grenoble Alpes, Institut Albert Bonniot, F-38000 Grenoble, France CNRS ERL 5284, F-38042 Grenoble, France
| | - Claude Verdier
- CNRS/Université Grenoble 1, LIPhy, UMR 5588, F-38041 Grenoble, France
| | - Valerie Deplano
- Aix-Marseille Université, CNRS, Centrale Marseille, IRPHE UMR 7342, F-13384, Marseille, France
| | - Christian Geindreau
- CNRS UMR5521, 3SR, Université Joseph Fourier Grenoble-INP, Grenoble, F-38042, France
| | - Eva Faurobert
- INSERM, Institut Albert Bonniot, F-38000 Grenoble, France Université Grenoble Alpes, Institut Albert Bonniot, F-38000 Grenoble, France CNRS ERL 5284, F-38042 Grenoble, France
| | - Corinne Albigès-Rizo
- INSERM, Institut Albert Bonniot, F-38000 Grenoble, France Université Grenoble Alpes, Institut Albert Bonniot, F-38000 Grenoble, France CNRS ERL 5284, F-38042 Grenoble, France
| | - Alain Duperray
- INSERM, Institut Albert Bonniot, F-38000 Grenoble, France Université Grenoble Alpes, Institut Albert Bonniot, F-38000 Grenoble, France
| |
Collapse
|
437
|
Wang CK, Zhang Y, Zhang ZJ, Qiu QW, Cao JG, He ZM. Effects of VBMDMP on the reversal of cisplatin resistance in human lung cancer A549/DDP cells. Oncol Rep 2014; 33:372-82. [PMID: 25394854 DOI: 10.3892/or.2014.3607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/20/2014] [Indexed: 11/05/2022] Open
Abstract
Tumor drug resistance is a major obstacle to cancer chemotherapy. We previously constructed a fusion protein based on two tumstatin-derived sequences named recombinant VBMDM (rVBMDMP). We preliminarily confirmed its inhibition of HUVEC and colon cancer cell growth. The present study further systematically observed the inhibitory effect of rVBMDMP on lung cancer cell growth and analyzed a possible mechanism to provide a theoretical basis for the development of new antitumor protein drugs. The effect of rVBMDMP on human lung adenocarcinoma (A549) and cisplatin-resistant human lung adenocarcinoma (A549/DDP) cell proliferation was evaluated by MTS assay. Hoechst 33342 staining performed together with fluorescence microscopy and immunoblot analysis were used to examine the effects of rVBMDMP on the apoptosis of A549/DDP cells. A protein phosphorylation chip was used to identify changes in rVBMDMP-induced signaling protein phosphorylation. Changes in the phosphatidylinositol 3 kinase (PI3K)/Akt signal transduction pathway and expression of multidrug resistance protein (MRP-2)-related molecules following rVBMDMP treatment in A549/DDP cells were evaluated by western blot analysis. A lung cancer xenograft model was used to evaluate the reversal effect of rVBMDMP on drug-resistance of A549/DDP cell tumors to cisplatin in vivo. The results demonstrated that rVBMDMP increased the phosphorylation of 79 signaling proteins, including focal adhesion kinase (FAK), caspase-6, Fas, FasL and FAF1 and downregulated 30 signaling proteins, including integrin αV, integrin β3, PI3K/Akt, NF-κB and MRP-2 compared with the controls. rVBMDMP also increased the sensitivity of A549 and A549/DDP cells to cisplatin and directly induced apoptosis, which may be related to MRP-2 and Bcl-2 downregulation. The effects of growth inhibition and apoptosis induction of rVBMDMP on A549/DDP cells may be related to the inhibition of integrin αVβ3 and PI3K/Akt protein phosphorylation. Finally, we observed an increase in cancer cell sensitivity to cisplatin by rVBMDMP using the A549/DDP cell xenograft model in nude mice. Our study suggests that rVBMDMP may be an effective potential chemotherapy sensitizer and may be a viable drug candidate in anticancer therapies.
Collapse
Affiliation(s)
- Cheng-Kun Wang
- Cancer Research Institute, Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou, Guandong 510182, P.R. China
| | - Yang Zhang
- Cancer Research Institute, University of South China, Hunan, Hengyang 421001, P.R. China
| | - Zhi-Jie Zhang
- Cancer Research Institute, Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou, Guandong 510182, P.R. China
| | - Qin-Wei Qiu
- Cancer Research Institute, Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou, Guandong 510182, P.R. China
| | - Jian-Guo Cao
- Medical College, Hunan Normal University, Hunan, Changsha 410006, P.R. China
| | - Zhi-Min He
- Cancer Research Institute, Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou, Guandong 510182, P.R. China
| |
Collapse
|
438
|
Nangami G, Koumangoye R, Shawn Goodwin J, Sakwe AM, Marshall D, Higginbotham J, Ochieng J. Fetuin-A associates with histones intracellularly and shuttles them to exosomes to promote focal adhesion assembly resulting in rapid adhesion and spreading in breast carcinoma cells. Exp Cell Res 2014; 328:388-400. [PMID: 25194507 DOI: 10.1016/j.yexcr.2014.08.037] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 08/08/2014] [Accepted: 08/23/2014] [Indexed: 01/11/2023]
Abstract
The present analyses were undertaken to define the mechanisms by which fetuin-A modulates cellular adhesion. FLAG-tagged fetuin-A was expressed in breast carcinoma and HEK-293T cells. We demonstrated by confocal microscopy that fetuin-A co-localizes with histone H2A in the cell nucleus, forms stable complexes with histones such as H2A and H3 in solution, and shuttles histones to exosomes. The rate of cellular adhesion and spreading to either fibronectin or laminin coated wells was accelerated significantly in the presence of either endogenous fetuin-A or serum derived protein. More importantly, the formation of focal adhesion complexes on surfaces coated by laminin or fibronectin was accelerated in the presence of fetuin-A or histone coated exosomes. Cellular adhesion mediated by histone coated exosomes was abrogated by heparin and heparinase III. Heparinase III cleaves heparan sulfate from cell surface heparan sulfate proteoglycans. Lastly, the uptake of histone coated exosomes and subsequent cellular adhesion, was abrogated by heparin. Taken together, the data suggest a mechanism where fetuin-A, either endogenously synthesized or supplied extracellularly can extract histones from the nucleus or elsewhere in the cytosol/membrane and load them on cellular exosomes which then mediate adhesion by interacting with cell surface heparan sulfate proteoglycans via bound histones.
Collapse
Affiliation(s)
- Gladys Nangami
- Departments of Biochemistry and Cancer Biology, Meharry Medical College, 1005 D.B. Todd Boulevard, Nashville, TN 37208, USA
| | - Rainelli Koumangoye
- Division of Surgical Oncology and Endocrine Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - J Shawn Goodwin
- Departments of Biochemistry and Cancer Biology, Meharry Medical College, 1005 D.B. Todd Boulevard, Nashville, TN 37208, USA
| | - Amos M Sakwe
- Departments of Biochemistry and Cancer Biology, Meharry Medical College, 1005 D.B. Todd Boulevard, Nashville, TN 37208, USA
| | - Dana Marshall
- Departments of Pathology, Anatomy and Cell Biology, Meharry Medical College, Nashville, TN 37208, USA
| | - James Higginbotham
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Josiah Ochieng
- Departments of Biochemistry and Cancer Biology, Meharry Medical College, 1005 D.B. Todd Boulevard, Nashville, TN 37208, USA.
| |
Collapse
|
439
|
Sun Z, Lambacher A, Fässler R. Nascent Adhesions: From Fluctuations to a Hierarchical Organization. Curr Biol 2014; 24:R801-3. [DOI: 10.1016/j.cub.2014.07.061] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
440
|
Poleshko A, Kossenkov AV, Shalginskikh N, Pecherskaya A, Einarson MB, Marie Skalka A, Katz RA. Human factors and pathways essential for mediating epigenetic gene silencing. Epigenetics 2014; 9:1280-9. [PMID: 25147916 PMCID: PMC4169020 DOI: 10.4161/epi.32088] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cellular identity in both normal and disease processes is determined by programmed epigenetic activation or silencing of specific gene subsets. Here, we have used human cells harboring epigenetically silent GFP-reporter genes to perform a genome-wide siRNA knockdown screen for the identification of cellular factors that are required to maintain epigenetic gene silencing. This unbiased screen interrogated 21,121 genes, and we identified and validated a set of 128 protein factors. This set showed enrichment for functional categories, and protein-protein interactions. Among this set were known epigenetic silencing factors, factors with no previously identified role in epigenetic gene silencing, as well as unstudied factors. The set included non-nuclear factors, for example, components of the integrin-adhesome. A key finding was that the E1 and E2 enzymes of the small ubiquitin-like modifier (SUMO) pathway (SAE1, SAE2/UBA2, UBC9/UBE2I) are essential for maintenance of epigenetic silencing. This work provides the first genome-wide functional view of human factors that mediate epigenetic gene silencing. The screen output identifies novel epigenetic factors, networks, and mechanisms, and provides a set of candidate targets for epigenetic therapy and cellular reprogramming.
Collapse
Affiliation(s)
| | - Andrew V Kossenkov
- Center for Systems and Computational Biology; The Wistar Institute; Philadelphia, PA USA
| | | | | | | | | | | |
Collapse
|
441
|
Adutler-Lieber S, Zaretsky I, Platzman I, Deeg J, Friedman N, Spatz JP, Geiger B. Engineering of synthetic cellular microenvironments: implications for immunity. J Autoimmun 2014; 54:100-11. [PMID: 24951031 DOI: 10.1016/j.jaut.2014.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 05/19/2014] [Indexed: 01/01/2023]
Abstract
In this article, we discuss novel synthetic approaches for studying the interactions of cells with their microenvironment. Notably, critical cellular processes such as growth, differentiation, migration, and fate determination, are tightly regulated by interactions with neighboring cells, and the surrounding extracellular matrix. Given the huge complexity of natural cellular environments, and their rich molecular and physical diversity, the mission of understanding "environmental signaling" at a molecular-mechanistic level appears to be extremely challenging. To meet these challenges, attempts have been made in recent years to design synthetic matrices with defined chemical and physical properties, which, artificial though they may be, could reveal basic "design principles" underlying the physiological processes. Here, we summarize recent developments in the characterization of the chemical and physical properties of cell sensing and adhesion, as well as the design and use of engineered, micro- to nanoscale patterned and confined environments, for systematic, comprehensive modulation of the cells' environment. The power of these biomimetic surfaces to highlight environmental signaling events in cells, and in immune cells in particular, will be discussed.
Collapse
Affiliation(s)
- Shimrit Adutler-Lieber
- Department of Molecular Cell Biology, Weizmann Institute of Science, 234 Herzl St., Rehovot 7610001, Israel.
| | - Irina Zaretsky
- Department of Immunology, Weizmann Institute of Science, 234 Herzl St., Rehovot 7610001, Israel.
| | - Ilia Platzman
- Max Planck Institute for Intelligent Systems & University of Heidelberg, Heisenbergstr. 3, 70569 Stuttgart, Germany.
| | - Janosch Deeg
- Max Planck Institute for Intelligent Systems & University of Heidelberg, Heisenbergstr. 3, 70569 Stuttgart, Germany.
| | - Nir Friedman
- Department of Immunology, Weizmann Institute of Science, 234 Herzl St., Rehovot 7610001, Israel.
| | - Joachim P Spatz
- Max Planck Institute for Intelligent Systems & University of Heidelberg, Heisenbergstr. 3, 70569 Stuttgart, Germany.
| | - Benjamin Geiger
- Department of Molecular Cell Biology, Weizmann Institute of Science, 234 Herzl St., Rehovot 7610001, Israel.
| |
Collapse
|
442
|
Schubert R, Strohmeyer N, Bharadwaj M, Ramanathan SP, Krieg M, Friedrichs J, Franz CM, Muller DJ. Assay for characterizing the recovery of vertebrate cells for adhesion measurements by single-cell force spectroscopy. FEBS Lett 2014; 588:3639-48. [PMID: 24928443 DOI: 10.1016/j.febslet.2014.06.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 05/30/2014] [Accepted: 06/02/2014] [Indexed: 11/30/2022]
Abstract
Single-cell force spectroscopy (SCFS) is becoming a widely used method to quantify the adhesion of a living cell to a substrate, another cell or tissue. The high sensitivity of SCFS permits determining the contributions of individual cell adhesion molecules (CAMs) to the adhesion force of an entire cell. However, to prepare adherent cells for SCFS, they must first be detached from tissue-culture flasks or plates. EDTA and trypsin are often applied for this purpose. Because cellular properties can be affected by this treatment, cells need to recover before being further characterized by SCFS. Here we introduce atomic force microscopy (AFM)-based SCFS to measure the mechanical and adhesive properties of HeLa cells and mouse embryonic kidney fibroblasts while they are recovering after detachment from tissue-culture. We find that mechanical and adhesive properties of both cell lines recover quickly (<10 min) after detachment using EDTA, while trypsin-detached fibroblasts require >60 min to fully recover. Our assay introduced to characterize the recovery of mammalian cells after detachment can in future be used to estimate the recovery behavior of other adherent cell types.
Collapse
Affiliation(s)
- Rajib Schubert
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Nico Strohmeyer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Mitasha Bharadwaj
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Subramanian P Ramanathan
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Michael Krieg
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Jens Friedrichs
- Leibniz Institute of Polymer Research Dresden, Institute for Biofunctional Polymer Materials, Hohe Str. 6, 01069 Dresden, Germany
| | - Clemens M Franz
- Karlsruhe Institute of Technology (KIT), DFG-Center for Functional Nanostructures, Wolfgang-Gaede-Str. 1a, 76131 Karlsruhe, Germany
| | - Daniel J Muller
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland.
| |
Collapse
|
443
|
Lennon R, Randles MJ, Humphries MJ. The importance of podocyte adhesion for a healthy glomerulus. Front Endocrinol (Lausanne) 2014; 5:160. [PMID: 25352829 PMCID: PMC4196579 DOI: 10.3389/fendo.2014.00160] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 09/21/2014] [Indexed: 12/23/2022] Open
Abstract
Podocytes are specialized epithelial cells that cover the outer surfaces of glomerular capillaries. Unique cell junctions, known as slit diaphragms, which feature nephrin and Neph family proteins in addition to components of adherens, tight, and gap junctions, connect adjacent podocyte foot processes. Single gene disorders affecting the slit diaphragm result in nephrotic syndrome in humans, characterized by massive loss of protein across the capillary wall. In addition to specialized cell junctions, interconnecting podocytes also adhere to the glomerular basement membrane (GBM) of the capillary wall. The GBM is a dense network of secreted, extracellular matrix (ECM) components and contains tissue-restricted isoforms of collagen IV and laminin in addition to other structural proteins and ECM regulators such as proteases and growth factors. The specialized niche of the GBM provides a scaffold for endothelial cells and podocytes to support their unique functions and human genetic mutations in GBM components lead to renal failure, thus highlighting the importance of cell-matrix interactions in the glomerulus. Cells adhere to ECM via adhesion receptors, including integrins, syndecans, and dystroglycan and in particular the integrin heterodimer α3β1 is required to maintain barrier integrity. Therefore, the sophisticated function of glomerular filtration relies on podocyte adhesion both at cell junctions and at the interface with the ECM. In health, the podocyte coordinates signals from cell junctions and cell-matrix interactions, in response to environmental cues in order to regulate filtration and as our understanding of mechanisms that control cell adhesion in the glomerulus develops, then insight into the effects of disease will improve. The ultimate goal will be to develop targeted therapies to prevent or repair defects in the filtration barrier and to restore glomerular function.
Collapse
Affiliation(s)
- Rachel Lennon
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
- Institute of Human Development, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK
- Department of Paediatric Nephrology, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
- *Correspondence: Rachel Lennon, Wellcome Trust Centre for Cell-Matrix Research, The University of Manchester, Michael Smith Building, Manchester M13 9PT, UK e-mail:
| | - Michael J. Randles
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
- Institute of Human Development, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK
| | - Martin J. Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
| |
Collapse
|