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Ng NHJ, Ghosh S, Bok CM, Ching C, Low BSJ, Chen JT, Lim E, Miserendino MC, Tan YS, Hoon S, Teo AKK. HNF4A and HNF1A exhibit tissue specific target gene regulation in pancreatic beta cells and hepatocytes. Nat Commun 2024; 15:4288. [PMID: 38909044 PMCID: PMC11193738 DOI: 10.1038/s41467-024-48647-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/08/2024] [Indexed: 06/24/2024] Open
Abstract
HNF4A and HNF1A encode transcription factors that are important for the development and function of the pancreas and liver. Mutations in both genes have been directly linked to Maturity Onset Diabetes of the Young (MODY) and type 2 diabetes (T2D) risk. To better define the pleiotropic gene regulatory roles of HNF4A and HNF1A, we generated a comprehensive genome-wide map of their binding targets in pancreatic and hepatic cells using ChIP-Seq. HNF4A was found to bind and regulate known (ACY3, HAAO, HNF1A, MAP3K11) and previously unidentified (ABCD3, CDKN2AIP, USH1C, VIL1) loci in a tissue-dependent manner. Functional follow-up highlighted a potential role for HAAO and USH1C as regulators of beta cell function. Unlike the loss-of-function HNF4A/MODY1 variant I271fs, the T2D-associated HNF4A variant (rs1800961) was found to activate AKAP1, GAD2 and HOPX gene expression, potentially due to changes in DNA-binding affinity. We also found HNF1A to bind to and regulate GPR39 expression in beta cells. Overall, our studies provide a rich resource for uncovering downstream molecular targets of HNF4A and HNF1A that may contribute to beta cell or hepatic cell (dys)function, and set up a framework for gene discovery and functional validation.
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Affiliation(s)
- Natasha Hui Jin Ng
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Soumita Ghosh
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore
| | - Chek Mei Bok
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Carmen Ching
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Blaise Su Jun Low
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Juin Ting Chen
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore
- Department of Biochemistry, National University of Singapore, Singapore, 117596, Singapore
| | - Euodia Lim
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
- Department of Biochemistry, National University of Singapore, Singapore, 117596, Singapore
| | - María Clara Miserendino
- Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
- Bioinformatics Institute, A*STAR, Singapore, 138671, Singapore
| | - Yaw Sing Tan
- Bioinformatics Institute, A*STAR, Singapore, 138671, Singapore
| | - Shawn Hoon
- Molecular Engineering Laboratory, IMCB, A*STAR, Singapore, 138673, Singapore
| | - Adrian Kee Keong Teo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore.
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore.
- Department of Biochemistry, National University of Singapore, Singapore, 117596, Singapore.
- Precision Medicine Translational Research Programme (TRP), National University of Singapore, Singapore, 119228, Singapore.
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2
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Deng H, Jia Q, Ming X, Sun Y, Lu Y, Liu L, Zhou J. Hippo pathway in intestinal diseases: focusing on ferroptosis. Front Cell Dev Biol 2023; 11:1291686. [PMID: 38130953 PMCID: PMC10734691 DOI: 10.3389/fcell.2023.1291686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023] Open
Abstract
The incidence of intestinal diseases, such as inflammatory bowel disease, gastric cancer, and colorectal cancer, has steadily increased over the past decades. The Hippo pathway is involved in cell proliferation, tissue and organ damage, energy metabolism, tumor formation, and other physiologic processes. Ferroptosis is a form of programmed cell death characterized by the accumulation of iron and lipid peroxides. The Hippo pathway and ferroptosis are associated with various intestinal diseases; however, the crosstalk between them is unclear. This review elaborates on the current research on the Hippo pathway and ferroptosis in the context of intestinal diseases. We summarized the connection between the Hippo pathway and ferroptosis to elucidate the underlying mechanism by which these pathways influence intestinal diseases. We speculate that a mutual regulatory mechanism exists between the Hippo pathway and ferroptosis and these two pathways interact in several ways to regulate intestinal diseases.
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Affiliation(s)
- Hongwei Deng
- Department of Anesthesiology, Southwest Medical University, Luzhou, China
- Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, Luzhou, China
| | - Qiuting Jia
- Department of Anesthesiology, Southwest Medical University, Luzhou, China
- Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, Luzhou, China
| | - Xin Ming
- Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, Luzhou, China
- School of Clinical Medicine, Southwest Medical University, Luzhou, China
| | - Yuxin Sun
- Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, Luzhou, China
- School of Basic Medicine, Southwest Medical University, Luzhou, China
| | - Yuxuan Lu
- Department of Anesthesiology, Southwest Medical University, Luzhou, China
- Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, Luzhou, China
| | - Li Liu
- Department of Anesthesiology, Southwest Medical University, Luzhou, China
- Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, Luzhou, China
- Department of Anesthesiology, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan, China
| | - Jun Zhou
- Department of Anesthesiology, Southwest Medical University, Luzhou, China
- Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, Luzhou, China
- Department of Anesthesiology, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan, China
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3
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Ramayo-Caldas Y, Crespo-Piazuelo D, Morata J, González-Rodríguez O, Sebastià C, Castello A, Dalmau A, Ramos-Onsins S, Alexiou KG, Folch JM, Quintanilla R, Ballester M. Copy Number Variation on ABCC2-DNMBP Loci Affects the Diversity and Composition of the Fecal Microbiota in Pigs. Microbiol Spectr 2023; 11:e0527122. [PMID: 37255458 PMCID: PMC10433821 DOI: 10.1128/spectrum.05271-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 05/16/2023] [Indexed: 06/01/2023] Open
Abstract
Genetic variation in the pig genome partially modulates the composition of porcine gut microbial communities. Previous studies have been focused on the association between single nucleotide polymorphisms (SNPs) and the gut microbiota, but little is known about the relationship between structural variants and fecal microbial traits. The main goal of this study was to explore the association between porcine genome copy number variants (CNVs) and the diversity and composition of pig fecal microbiota. For this purpose, we used whole-genome sequencing data to undertake a comprehensive identification of CNVs followed by a genome-wide association analysis between the estimated CNV status and the fecal bacterial diversity in a commercial Duroc pig population. A CNV predicted as gain (DUP) partially harboring ABCC2-DNMBP loci was associated with richness (P = 5.41 × 10-5, false discovery rate [FDR] = 0.022) and Shannon α-diversity (P = 1.42 × 10-4, FDR = 0.057). The in silico predicted gain of copies was validated by real-time quantitative PCR (qPCR), and its segregation, and positive association with the richness and Shannon α-diversity of the porcine fecal bacterial ecosystem was confirmed in an unrelated F1 (Duroc × Iberian) cross. Our results advise the relevance of considering the role of host-genome structural variants as potential modulators of microbial ecosystems and suggest the ABCC2-DNMBP CNV as a host-genetic factor for the modulation of the diversity and composition of the fecal microbiota in pigs. IMPORTANCE A better understanding of the environmental and host factors modulating gut microbiomes is a topic of greatest interest. Recent evidence suggests that genetic variation in the pig genome partially controls the composition of porcine gut microbiota. However, since previous studies have been focused on the association between single nucleotide polymorphisms and the fecal microbiota, little is known about the relationship between other sources of genetic variation, like the structural variants and microbial traits. Here, we identified, experimentally validated, and replicated in an independent population a positive link between the gain of copies of ABCC2-DNMBP loci and the diversity and composition of pig fecal microbiota. Our results advise the relevance of considering the role of host-genome structural variants as putative modulators of microbial ecosystems and open the possibility of implementing novel holobiont-based management strategies in breeding programs for the simultaneous improvement of microbial traits and host performance.
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Affiliation(s)
- Yuliaxis Ramayo-Caldas
- Animal Breeding and Genetics Program, Institute of Agrifood Research and Technology, Caldes de Montbui, Spain
| | - Daniel Crespo-Piazuelo
- Animal Breeding and Genetics Program, Institute of Agrifood Research and Technology, Caldes de Montbui, Spain
| | - Jordi Morata
- Centro Nacional de Análisis Genómico, Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Olga González-Rodríguez
- Animal Breeding and Genetics Program, Institute of Agrifood Research and Technology, Caldes de Montbui, Spain
| | - Cristina Sebastià
- Plant and Animal Genomics Program, Centre for Research in Agricultural Genomics, Consejo Superior de Investigaciones Científicas (CSIC)-Institute of Agrifood Research and Technology-Autonomous University of Barcelona-UB, Bellaterra, Spain
- Animal and Food Science Department, Autonomous University of Barcelona, Bellaterra, Spain
| | - Anna Castello
- Plant and Animal Genomics Program, Centre for Research in Agricultural Genomics, Consejo Superior de Investigaciones Científicas (CSIC)-Institute of Agrifood Research and Technology-Autonomous University of Barcelona-UB, Bellaterra, Spain
- Animal and Food Science Department, Autonomous University of Barcelona, Bellaterra, Spain
| | - Antoni Dalmau
- Animal Welfare Program, Institute of Agrifood Research and Technology, Girona, Spain
| | - Sebastian Ramos-Onsins
- Plant and Animal Genomics Program, Centre for Research in Agricultural Genomics, Consejo Superior de Investigaciones Científicas (CSIC)-Institute of Agrifood Research and Technology-Autonomous University of Barcelona-UB, Bellaterra, Spain
| | - Konstantinos G. Alexiou
- Plant and Animal Genomics Program, Centre for Research in Agricultural Genomics, Consejo Superior de Investigaciones Científicas (CSIC)-Institute of Agrifood Research and Technology-Autonomous University of Barcelona-UB, Bellaterra, Spain
| | - Josep M. Folch
- Plant and Animal Genomics Program, Centre for Research in Agricultural Genomics, Consejo Superior de Investigaciones Científicas (CSIC)-Institute of Agrifood Research and Technology-Autonomous University of Barcelona-UB, Bellaterra, Spain
- Animal and Food Science Department, Autonomous University of Barcelona, Bellaterra, Spain
| | - Raquel Quintanilla
- Animal Breeding and Genetics Program, Institute of Agrifood Research and Technology, Caldes de Montbui, Spain
| | - Maria Ballester
- Animal Breeding and Genetics Program, Institute of Agrifood Research and Technology, Caldes de Montbui, Spain
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Sharkova M, Chow E, Erickson T, Hocking JC. The morphological and functional diversity of apical microvilli. J Anat 2023; 242:327-353. [PMID: 36281951 PMCID: PMC9919547 DOI: 10.1111/joa.13781] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/30/2022] Open
Abstract
Sensory neurons use specialized apical processes to perceive external stimuli and monitor internal body conditions. The apical apparatus can include cilia, microvilli, or both, and is adapted for the functions of the particular cell type. Photoreceptors detect light through a large, modified cilium (outer segment), that is supported by a surrounding ring of microvilli-like calyceal processes (CPs). Although first reported 150 years ago, CPs remain poorly understood. As a basis for future study, we therefore conducted a review of existing literature about sensory cell microvilli, which can act either as the primary sensory detector or as support for a cilia-based detector. While all microvilli are finger-like cellular protrusions with an actin core, the processes vary across cell types in size, number, arrangement, dynamics, and function. We summarize the current state of knowledge about CPs and the characteristics of the microvilli found on inner ear hair cells (stereocilia) and cerebral spinal fluid-contacting neurons, with comparisons to the brush border of the intestinal and renal epithelia. The structure, stability, and dynamics of the actin core are regulated by a complement of actin-binding proteins, which includes both common components and unique features when compared across cell types. Further, microvilli are often supported by lateral links, a glycocalyx, and a defined extracellular matrix, each adapted to the function and environment of the cell. Our comparison of microvillar features will inform further research into how CPs support photoreceptor function, and also provide a general basis for investigations into the structure and functions of apical microvilli found on sensory neurons.
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Affiliation(s)
- Maria Sharkova
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Erica Chow
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Timothy Erickson
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Jennifer C Hocking
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Division of Anatomy, Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
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5
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Morales EA, Gaeta I, Tyska MJ. Building the brush border, one microvillus at a time. Curr Opin Cell Biol 2023; 80:102153. [PMID: 36827850 PMCID: PMC10033394 DOI: 10.1016/j.ceb.2023.102153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 01/11/2023] [Accepted: 01/19/2023] [Indexed: 02/24/2023]
Abstract
Microvilli are actin bundle-supported surface protrusions assembled by diverse cell types to mediate biochemical and physical interactions with the external environment. Found on the surface of some of the earliest animal cells, primordial microvilli likely contributed to bacterial entrapment and feeding. Although millions of years of evolution have repurposed these protrusions to fulfill diverse roles such as detection of mechanical or visual stimuli in inner ear hair cells or retinal pigmented epithelial cells, respectively, solute uptake remains a key essential function linked to these structures. In this mini review, we offer a brief overview of the composition and structure of epithelial microvilli, highlight recent discoveries on the growth of these protrusions early in differentiation, and point to fundamental questions surrounding microvilli biogenesis that remain open for future studies.
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Affiliation(s)
- E Angelo Morales
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Isabella Gaeta
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA.
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6
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Felipe-López A, Hansmeier N, Danzer C, Hensel M. Manipulation of microvillar proteins during Salmonella enterica invasion results in brush border effacement and actin remodeling. Front Cell Infect Microbiol 2023; 13:1137062. [PMID: 36936760 PMCID: PMC10018140 DOI: 10.3389/fcimb.2023.1137062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 02/10/2023] [Indexed: 03/06/2023] Open
Abstract
Enterocyte invasion by the gastrointestinal pathogen Salmonella enterica is accompanied by loss of brush border and massive remodeling of the actin cytoskeleton, leading to microvilli effacement and formation of membrane ruffles. These manipulations are mediated by effector proteins translocated by the Salmonella Pathogenicity Island 1-encoded type III secretion system (SPI1-T3SS). To unravel the mechanisms of microvilli effacement and contribution of SPI1-T3SS effector proteins, the dynamics of host-pathogen interactions was analyzed using live cell imaging (LCI) of polarized epithelial cells (PEC) expressing LifeAct-GFP. PEC were infected with S. enterica wild-type and mutant strains with defined defects in SPI1-T3SS effector proteins, and pharmacological inhibition of actin assembly were applied. We identified that microvilli effacement involves two distinct mechanisms: i) F-actin depolymerization mediated by villin and ii), the consumption of cytoplasmic G-actin by formation of membrane ruffles. By analyzing the contribution of individual SPI1-T3SS effector proteins, we demonstrate that SopE dominantly triggers microvilli effacement and formation of membrane ruffles. Furthermore, SopE via Rac1 indirectly manipulates villin, which culminates in F-actin depolymerization. Collectively, these results indicate that SopE has dual functions during F-actin remodeling in PEC. While SopE-Rac1 triggers F-actin polymerization and ruffle formation, activation of PLCγ and villin by SopE depolymerizes F-actin in PEC. These results demonstrate the key role of SopE in destruction of the intestinal barrier during intestinal infection by Salmonella.
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Affiliation(s)
| | | | - Claudia Danzer
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Michael Hensel
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
- *Correspondence: Michael Hensel,
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Morales EA, Arnaiz C, Krystofiak ES, Zanic M, Tyska MJ. Mitotic Spindle Positioning (MISP) is an actin bundler that selectively stabilizes the rootlets of epithelial microvilli. Cell Rep 2022; 39:110692. [PMID: 35443169 PMCID: PMC9097542 DOI: 10.1016/j.celrep.2022.110692] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 01/20/2022] [Accepted: 03/24/2022] [Indexed: 11/11/2022] Open
Abstract
Microvilli are conserved actin-based surface protrusions that have been repurposed throughout evolution to fulfill diverse cell functions. In the case of transporting epithelia, microvilli are supported by a core of actin filaments bundled in parallel by villin, fimbrin, and espin. Remarkably, microvilli biogenesis persists in mice lacking all three of these factors, suggesting the existence of unknown bundlers. We identified Mitotic Spindle Positioning (MISP) as an actin-binding factor that localizes specifically to the rootlet end of the microvillus. MISP promotes rootlet elongation in cells, and purified MISP exhibits potent filament bundling activity in vitro. MISP-bundled filaments also recruit fimbrin, which further elongates and stabilizes bundles. MISP confinement to the rootlet is enforced by ezrin, which prevents decoration of the membrane-wrapped distal end of the core bundle. These discoveries reveal how epithelial cells optimize apical membrane surface area and offer insight on the remarkable robustness of microvilli biogenesis. Morales et al. identify Mitotic Spindle Positioning (MISP) as an actin bundler in the rootlets of epithelial microvilli. MISP cooperates with other bundlers, and its rootlet-specific localization is enforced by membrane-actin linker ezrin. These findings illuminate mechanisms that drive the assembly and compartmentalization of actin bundle-supported protrusions.
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Affiliation(s)
- E Angelo Morales
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Cayetana Arnaiz
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Evan S Krystofiak
- Cell Imaging Shared Resource, Vanderbilt University, Nashville, TN 37232, USA
| | - Marija Zanic
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.
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8
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Clinical Significance of Circulating Tumor Cell Induced Epithelial-Mesenchymal Transition in Patients with Metastatic Colorectal Cancer by Single-Cell RNA-Sequencing. Cancers (Basel) 2021; 13:cancers13194862. [PMID: 34638346 PMCID: PMC8507666 DOI: 10.3390/cancers13194862] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/18/2021] [Accepted: 09/25/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Circulating tumor cells (CTCs) are a prognostic marker in patients with metastatic colorectal cancer (mCRC). However, little is known about the characterization of CTCs in mCRC at the single-cell level using RNA sequencing. The purpose of this study was to validate the capability to detect and isolate single CTCs for single-cell RNA sequencing (scRNA-seq) and to identify clinical significance at a single CTC level. METHODS Single CTCs from 27 mCRC patients were collected by CTC-FIND, which is comprised of filter separation and immunomagnetic depletion to collect ultra-pure CTC samples. To address tumor heterogeneity, CTCs were collected without relying on any traditional CTC markers, such as epithelial and mesenchymal cell antigens, and were undertaken by scRNA-seq using SMART-Seq v4. RESULTS We identified 59 single CTCs which were classified into four groups by epithelial, epithelial-mesenchymal transition (EMT) and stem cell-related gene expression. Patients receiving second or later-line treatment who had EMT gene expressing CTCs had a significantly shorter PFS and OS. CONCLUSIONS Exploiting CTC-FIND with SMART-Seq v4 showed that scRNA-seq of CTCs may shed new insight into tumor heterogeneity of mCRC and that the presence of CTCs expressing EMT-related genes at the single-cell level could have prognostic value in mCRC patients.
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Vasilev F, Ezhova Y, Chun JT. Signaling Enzymes and Ion Channels Being Modulated by the Actin Cytoskeleton at the Plasma Membrane. Int J Mol Sci 2021; 22:ijms221910366. [PMID: 34638705 PMCID: PMC8508623 DOI: 10.3390/ijms221910366] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/23/2021] [Accepted: 09/23/2021] [Indexed: 02/06/2023] Open
Abstract
A cell should deal with the changing external environment or the neighboring cells. Inevitably, the cell surface receives and transduces a number of signals to produce apt responses. Typically, cell surface receptors are activated, and during this process, the subplasmalemmal actin cytoskeleton is often rearranged. An intriguing point is that some signaling enzymes and ion channels are physically associated with the actin cytoskeleton, raising the possibility that the subtle changes of the local actin cytoskeleton can, in turn, modulate the activities of these proteins. In this study, we reviewed the early and new experimental evidence supporting the notion of actin-regulated enzyme and ion channel activities in various cell types including the cells of immune response, neurons, oocytes, hepatocytes, and epithelial cells, with a special emphasis on the Ca2+ signaling pathway that depends on the synthesis of inositol 1,4,5-trisphosphate. Some of the features that are commonly found in diverse cells from a wide spectrum of the animal species suggest that fine-tuning of the activities of the enzymes and ion channels by the actin cytoskeleton may be an important strategy to inhibit or enhance the function of these signaling proteins.
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Affiliation(s)
- Filip Vasilev
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), 900 Rue St Denis, Montreal, QC H2X 0A9, Canada
- Correspondence: (F.V.); (J.T.C.); Tel.: +1-514-249-5862 (F.V.); +39-081-583-3407 (J.T.C.)
| | - Yulia Ezhova
- Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, QC H1T 2M4, Canada;
| | - Jong Tai Chun
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy
- Correspondence: (F.V.); (J.T.C.); Tel.: +1-514-249-5862 (F.V.); +39-081-583-3407 (J.T.C.)
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10
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Intestinal brush border assembly during the peri-hatch period and its contribution to surface area expansion. Poult Sci 2021; 100:101401. [PMID: 34464930 PMCID: PMC8408528 DOI: 10.1016/j.psj.2021.101401] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/31/2021] [Accepted: 07/20/2021] [Indexed: 12/01/2022] Open
Abstract
Microvilli generate the small intestinal brush border, the main site of nutrient digestion and absorption. Mucosal structuring of the small intestine of chicken during the perihatch period has been widely researched, yet the developmental dynamics of microvilli during this period have not been fully characterized. In this study, we examined the structural and molecular characteristics of microvilli assembly and maturation during the perihatch period. Small intestines of broiler embryos and chicks were sampled at prehatch ages 17 E and 19 E, at day of hatch (DOH) and at 1, 3, 7, and 10 d posthatch. Morphological evaluations and measurements were conducted by scanning electron microscopy (SEM) and light microscopy (LM) (n = 3/timepoint), and expression of microvilli structural genes Plastin 1, Ezrin, and Myo1a was examined by Real-Time qPCR (n = 6/timepoint). Results revealed dissimilar patterns of microvilli and villi development during the perihatch period. From 19 E to 1 d, microvilli lengths increased 4.3-fold while villi lengths increased 2.8-fold (P < 0.0001). From 3 to 7 d, villi lengths increased by 20% (P < 0.005), while microvilli lengths decreased by 41% (P = 0.001). At 10 d, microvilli lengths stabilized, while villi continued to elongate by 26% (P < 0.0001). Estimations of the microvilli amplification factor (MAF) and total enterocyte surface area (TESA) revealed similar trends, with peak values of 78.53 and 1961.67 µm2, respectively, at 3 d. Microvilli structural gene expression portrayed diverse patterns. Expression of Plastin 1, which bundles and binds actin cores to the terminal web, increased 8.7-fold between 17 E and DOH (P = 0.005), and gradually increased up to 7 d (P = 0.045). Ezrin and Myo1a, both actin core-cell membrane cross-linkers, portrayed different expression patterns throughout the perihatch period, as Ezrin expression was relatively stable, while Myo1a expression increased 15.8-fold between 17 E and 10 d (P < 0.0001). We conclude that microvilli assembly during the perihatch period is a rapid, coordinated process, which dramatically expands the digestive and absorptive surface area of the small intestine before the completion of villi maturation.
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11
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Chen L, Luo S, Dupre A, Vasoya RP, Parthasarathy A, Aita R, Malhotra R, Hur J, Toke NH, Chiles E, Yang M, Cao W, Flores J, Ellison CE, Gao N, Sahota A, Su X, Bonder EM, Verzi MP. The nuclear receptor HNF4 drives a brush border gene program conserved across murine intestine, kidney, and embryonic yolk sac. Nat Commun 2021; 12:2886. [PMID: 34001900 PMCID: PMC8129143 DOI: 10.1038/s41467-021-22761-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 03/24/2021] [Indexed: 12/12/2022] Open
Abstract
The brush border is comprised of microvilli surface protrusions on the apical surface of epithelia. This specialized structure greatly increases absorptive surface area and plays crucial roles in human health. However, transcriptional regulatory networks controlling brush border genes are not fully understood. Here, we identify that hepatocyte nuclear factor 4 (HNF4) transcription factor is a conserved and important regulator of brush border gene program in multiple organs, such as intestine, kidney and yolk sac. Compromised brush border gene signatures and impaired transport were observed in these tissues upon HNF4 loss. By ChIP-seq, we find HNF4 binds and activates brush border genes in the intestine and kidney. H3K4me3 HiChIP-seq identifies that HNF4 loss results in impaired chromatin looping between enhancers and promoters at gene loci of brush border genes, and instead enhanced chromatin looping at gene loci of stress fiber genes in the intestine. This study provides comprehensive transcriptional regulatory mechanisms and a functional demonstration of a critical role for HNF4 in brush border gene regulation across multiple murine epithelial tissues.
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Affiliation(s)
- Lei Chen
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA.
- Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA.
| | - Shirley Luo
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Abigail Dupre
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Roshan P Vasoya
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Aditya Parthasarathy
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Rohit Aita
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Raj Malhotra
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Joseph Hur
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Natalie H Toke
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Eric Chiles
- Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Min Yang
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Weihuan Cao
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Juan Flores
- Department of Biological Sciences, Rutgers University, Newark, NJ, USA
| | - Christopher E Ellison
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Nan Gao
- Department of Biological Sciences, Rutgers University, Newark, NJ, USA
| | - Amrik Sahota
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Xiaoyang Su
- Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
- Department of Medicine, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Edward M Bonder
- Department of Biological Sciences, Rutgers University, Newark, NJ, USA
| | - Michael P Verzi
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA.
- Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA.
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition & Health, Rutgers University, New Brunswick, NJ, USA.
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12
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Cizkova K, Koubova K, Foltynkova T, Jiravova J, Tauber Z. Soluble Epoxide Hydrolase as an Important Player in Intestinal Cell Differentiation. Cells Tissues Organs 2021; 209:177-188. [PMID: 33588415 DOI: 10.1159/000512807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 11/05/2020] [Indexed: 11/19/2022] Open
Abstract
There is growing evidence that soluble epoxide hydrolase (sEH) may play a role in cell differentiation. sEH metabolizes biologically highly active and generally cytoprotective epoxyeicosatrienoic acids (EETs), generated from arachidonic acid metabolism by CYP epoxygenases (CYP2C and CYP2J subfamilies), to less active corresponding diols. We investigated the effect of sEH inhibitor (TPPU) on the expression of villin, CYP2C8, CYP2C9, CYP2J2, and sEH in undifferentiated and in vitro differentiated HT-29 and Caco2 cell lines. The administration of 10 μM TPPU on differentiated HT-29 and Caco2 cells resulted in a significant decrease in expression of villin, a marker for intestinal cell differentiation. It was accompanied by a disruption of the brush border when microvilli appeared sparse and short in atomic force microscope scans of HT-29 cells. Although inhibition of sEH in differentiated HT-29 and Caco2 cells led to an increase in sEH expression in both cell lines, this treatment had an opposite effect on CYP2J2 expression in HT-29 and Caco2 cells. In addition, tissue samples of colorectal carcinoma and adjacent normal tissues from 45 patients were immunostained for sEH and villin. We detected a significant decrease in the expression of both proteins in colorectal carcinoma in comparison to adjacent normal tissue, and the decrease in both sEH and villin expression revealed a moderate positive association. Taken together, our results showed that sEH is an important player in intestinal cell differentiation.
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Affiliation(s)
- Katerina Cizkova
- Department of Histology and Embryology, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czechia
| | - Katerina Koubova
- Department of Histology and Embryology, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czechia
| | - Tereza Foltynkova
- Department of Histology and Embryology, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czechia
| | - Jana Jiravova
- Department of Medical Biophysics, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czechia
| | - Zdenek Tauber
- Department of Histology and Embryology, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czechia,
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13
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Modulation of the immune response and metabolism in germ-free rats colonized by the probiotic Lactobacillus salivarius LI01. Appl Microbiol Biotechnol 2021; 105:1629-1645. [PMID: 33507355 DOI: 10.1007/s00253-021-11099-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/21/2020] [Accepted: 01/05/2021] [Indexed: 01/06/2023]
Abstract
The gut microbiota plays an important role in multifaceted physiological functions in the host. Previous studies have assessed the probiotic effects of Lactobacillus salivarius LI01. In this study, we aimed to investigate the potential effects and putative mechanism of L. salivarius LI01 in immune modulation and metabolic regulation through the monocolonization of germ-free (GF) Sprague-Dawley (SD) rats with L. salivarius LI01. The GF rats were separated into two groups and administered a gavage of L. salivarius LI01 or an equal amount of phosphate-buffered saline. The levels of serum biomarkers, such as interleukin (IL)-1α, IL-5, and IL-10, were restored by L. salivarius LI01, which indicated the activation of Th0 cell differentiation toward immune homeostasis. L. salivarius LI01 also stimulated the immune response and metabolic process by altering transcriptional expression in the ileum and liver. A Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed significant enrichment of the 5'-adenosine monophosphate-activated protein kinase (AMPK) signaling pathway, which indicated that L. salivarius LI01 exerts an effect on energy accumulation. The LI01 group showed alterations in fecal carbohydrates accompanied by an increased body weight gain. In addition, L. salivarius LI01 produced indole-3-lactic acid (ILA) and enhanced arginine metabolism by rebalancing the interconversion between arginine and proline. These findings provide evidence showing that L. salivarius LI01 can directly impact the host by modulating immunity and metabolism. KEY POINTS : • Lactobacillus salivarius LI01 conventionalizes the cytokine profile and activates the immune response. • LI01 modulates carbohydrate metabolism and arginine transaction. • LI01 generates tryptophan-derived indole-3-lactic acid. • The cytochrome P450 family contributes to the response to altered metabolites.
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14
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Pintér R, Huber T, Bukovics P, Gaszler P, Vig AT, Tóth MÁ, Gazsó-Gerhát G, Farkas D, Migh E, Mihály J, Bugyi B. The Activities of the Gelsolin Homology Domains of Flightless-I in Actin Dynamics. Front Mol Biosci 2020; 7:575077. [PMID: 33033719 PMCID: PMC7509490 DOI: 10.3389/fmolb.2020.575077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/14/2020] [Indexed: 12/12/2022] Open
Abstract
Flightless-I is a unique member of the gelsolin superfamily alloying six gelsolin homology domains and leucine-rich repeats. Flightless-I is an established regulator of the actin cytoskeleton, however, its biochemical activities in actin dynamics are still largely elusive. To better understand the biological functioning of Flightless-I we studied the actin activities of Drosophila Flightless-I by in vitro bulk fluorescence spectroscopy and single filament fluorescence microscopy, as well as in vivo genetic approaches. Flightless-I was found to interact with actin and affects actin dynamics in a calcium-independent fashion in vitro. Our work identifies the first three gelsolin homology domains (1–3) of Flightless-I as the main actin-binding site; neither the other three gelsolin homology domains (4–6) nor the leucine-rich repeats bind actin. Flightless-I inhibits polymerization by high-affinity (∼nM) filament barbed end capping, moderately facilitates nucleation by low-affinity (∼μM) monomer binding, and does not sever actin filaments. Our work reveals that in the presence of profilin Flightless-I is only able to cap actin filament barbed ends but fails to promote actin assembly. In line with the in vitro data, while gelsolin homology domains 4–6 have no effect on in vivo actin polymerization, overexpression of gelsolin homology domains 1–3 prevents the formation of various types of actin cables in the developing Drosophila egg chambers. We also show that the gelsolin homology domains 4–6 of Flightless-I interact with the C-terminus of Drosophila Disheveled-associated activator of morphogenesis formin and negatively regulates its actin assembly activity.
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Affiliation(s)
- Réka Pintér
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary
| | - Tamás Huber
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary
| | - Péter Bukovics
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary
| | - Péter Gaszler
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary
| | - Andrea Teréz Vig
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary
| | - Mónika Ágnes Tóth
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary
| | - Gabriella Gazsó-Gerhát
- Biological Research Centre Szeged, Institute of Genetics, Szeged, Hungary.,Faculty of Science and Informatics, Doctoral School in Biology, University of Szeged, Szeged, Hungary
| | - Dávid Farkas
- Biological Research Centre Szeged, Institute of Genetics, Szeged, Hungary
| | - Ede Migh
- Biological Research Centre Szeged, Institute of Genetics, Szeged, Hungary
| | - József Mihály
- Biological Research Centre Szeged, Institute of Genetics, Szeged, Hungary
| | - Beáta Bugyi
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary.,Szentágothai Research Center, Pécs, Hungary
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15
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Kuo WT, Shen L, Zuo L, Shashikanth N, Ong MLDM, Wu L, Zha J, Edelblum KL, Wang Y, Wang Y, Nilsen SP, Turner JR. Inflammation-induced Occludin Downregulation Limits Epithelial Apoptosis by Suppressing Caspase-3 Expression. Gastroenterology 2019; 157:1323-1337. [PMID: 31401143 PMCID: PMC6815722 DOI: 10.1053/j.gastro.2019.07.058] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 07/15/2019] [Accepted: 07/22/2019] [Indexed: 12/22/2022]
Abstract
BACKGROUND & AIMS Epithelial tight junctions are compromised in gastrointestinal disease. Processes that contribute to the resulting barrier loss include endocytic occludin removal from the tight junction and reduced occludin expression. Nevertheless, the relatively-normal basal phenotype of occludin knockout (KO) mice has been taken as evidence that occludin does not contribute to gastrointestinal barrier function. We asked whether stress could unmask occludin functions within intestinal epithelia. METHODS Wildtype (WT), universal and intestinal epithelial-specific occludin KO, and villin-EGFP-occludin transgenic mice as well as WT and occludin knockdown (KD) Caco-2BBe cell monolayers were challenged with DSS, TNBS, staurosporine, 5-FU, or TNF. Occludin and caspase-3 expression were assessed in patient biopsies. RESULTS Intestinal epithelial occludin loss limited severity of DSS- and TNBS-induced colitis due to epithelial resistance to apoptosis; activation of both intrinsic and extrinsic apoptotic pathways was blocked in occludin KO epithelia. Promoter analysis revealed that occludin enhances CASP3 transcription and, conversely, that occludin downregulation reduces caspase-3 expression. Analysis of biopsies from Crohn's disease and ulcerative colitis patients and normal controls demonstrated that disease-associated occludin downregulation was accompanied by and correlated with reduced caspase-3 expression. In vitro, cytokine-induced occludin downregulation resulted in reduced caspase-3 expression and resistance to intrinsic and extrinsic pathway apoptosis, demonstrating an overall protective effect of inflammation-induced occludin loss. CONCLUSIONS The tight junction protein occludin regulates apoptosis by enhancing caspase-3 transcription. These data suggest that reduced epithelial caspase-3 expression downstream of occludin downregulation is a previously-unappreciated anti-apoptotic process that contributes to mucosal homeostasis in inflammatory conditions.
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Affiliation(s)
- Wei-Ting Kuo
- Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115
| | - Le Shen
- Department of Pathology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637
| | - Li Zuo
- Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115,Anhui Medical University, 81 Meishan Road, Hefei, Anhui, China
| | - Nitesh Shashikanth
- Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115
| | - Ma. Lora Drizella M. Ong
- Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115
| | - Licheng Wu
- Department of Pathology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637
| | - Juanmin Zha
- Department of Pathology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637,Soochow University and Department of Oncology, The First Affiliated Hospital of Soochow University, 296 Shizi Street, Suzhou, 215123, China
| | - Karen L. Edelblum
- Department of Pathology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637,Department of Pathology & Laboratory Medicine, Center for Inflammation and Immunity, Rutgers New Jersey Medical School, Cancer Center, 205 South Orange Avenue, G1228, Newark, New Jersey 07103
| | - Yitang Wang
- Department of Pathology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637
| | - Yingmin Wang
- Department of Pathology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637
| | - Steven P. Nilsen
- Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115
| | - Jerrold R. Turner
- Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115,Department of Pathology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637,Correspondence to: Jerrold R. Turner, MD, Ph.D., Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, HNRB 730B, , 617-525-8165
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16
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Markovic MA, Brubaker PL. The roles of glucagon-like peptide-2 and the intestinal epithelial insulin-like growth factor-1 receptor in regulating microvillus length. Sci Rep 2019; 9:13010. [PMID: 31506583 PMCID: PMC6737075 DOI: 10.1038/s41598-019-49510-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 08/27/2019] [Indexed: 12/25/2022] Open
Abstract
Microvilli are tiny projections on the apical end of enterocytes, aiding in the digestion and absorption of nutrients. One of their key features is uniform length, but how this is regulated is poorly understood. Glucagon-like peptide-2 (GLP-2) has been shown to increase microvillus length but, the requirement of its downstream mediator, the intestinal epithelial insulin-like growth factor-1 receptor (IE-IGF-1R), and the microvillus proteins acted upon by GLP-2, remain unknown. Using IE-IGF-1R knockout (KO) mice, treated with either long-acting human (h) (GLY2)GLP-2 or vehicle for 11d, it was found that the h(GLY2)GLP-2-induced increase in microvillus length required the IE-IGF-1R. Furthermore, IE-IGF-1R KO alone resulted in a significant decrease in microvillus length. Examination of the brush border membrane proteome as well as of whole jejunal mucosa demonstrated that villin was increased with h(GLY2)GLP-2 treatment in an IE-IGF-1R-dependent manner. Under both basal conditions and with h(GLY2)GLP-2 treatment of the IE-IGF-1R KO mice, changes in villin, IRTKS-1, harmonin, β-actin, and myosin-1a did not explain the decrease in microvillus length, in either the brush border or jejunal mucosa of KO animals. Collectively, these studies define a new role for the IE-IGF-1R within the microvillus, in both the signaling cascade induced by GLP-2, as well as endogenously.
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Affiliation(s)
- Melanie A Markovic
- Department of Physiology Rm 3366 Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Patricia L Brubaker
- Department of Physiology Rm 3366 Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada. .,Department of Medicine Rm 3366 Medical Sciences Building, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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17
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Kang B, Jo S, Baek J, Nakamura F, Hwang W, Lee H. Role of mechanical flow for actin network organization. Acta Biomater 2019; 90:217-224. [PMID: 30928733 DOI: 10.1016/j.actbio.2019.03.054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/28/2019] [Accepted: 03/26/2019] [Indexed: 11/30/2022]
Abstract
The major cytoskeletal protein actin forms complex networks to provide structural support and perform vital functions in cells. In vitro studies have revealed that the structure of the higher-order actin network is determined primarily by the type of actin binding protein (ABP). By comparison, there are far fewer studies about the role of the mechanical environment for the organization of the actin network. In particular, the duration over which cells reorganize their shape in response to functional demands is relatively short compared to the in vitro protein polymerization time, suggesting that such changes can influence the actin network formation. We hypothesize that mechanical flows in the cytoplasm generated by exogenous and endogenous stimulation play a key role in the spatiotemporal regulation of the actin architecture. To mimic cytoplasmic streaming, we generated a circulating flow using surface acoustic wave in a microfluidic channel and investigated its effect on the formation of networks by actin and ABPs. We found that the mechanical flow affected the orientation and thickness of actin bundles, depending on the type and concentration of ABPs. Our computational model shows that the extent of alignment and thickness of actin bundle are determined by the balance between flow-induced drag forces and the tendency of ABPs to crosslink actin filaments at given angles. These results suggest that local intracellular flows can affect the assembly dynamics and morphology of the actin cytoskeleton. STATEMENT OF SIGNIFICANCE: Spatiotemporal regulation of actin cytoskeleton structure is essential in many cellular functions. It has been shown that mechanical cues including an applied force and geometric boundary can alter the structural characteristics of actin network. However, even though the cytoplasm accounts for a large portion of the cell volume, the effect of the cytoplasmic streaming flow produced during cell dynamics on actin network organization has not been reported. In this study, we demonstrated that the mechanical flow exerted during actin network organization play an important role in determining the orientation and dimension of actin bundle network. Our result will be beneficial in understanding the mechanism of the actin network reorganization occurred during physiological and pathological processes.
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Affiliation(s)
- Byungjun Kang
- School of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Seunghan Jo
- School of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Jonghyeok Baek
- School of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Fumihiko Nakamura
- School of Pharmaceutical Science and Technology, Health Sciences Platform, Tianjin University, Tianjin 300072, China
| | - Wonmuk Hwang
- Departments of Biomedical Engineering, Materials Science & Engineering, and Physics & Astronomy, Texas A&M University, College Station, TX 77843, USA; School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
| | - Hyungsuk Lee
- School of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea.
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18
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Zhang S, Wang C, Xie M, Liu J, Kong Z, Su H. Actin Bundles in The Pollen Tube. Int J Mol Sci 2018; 19:ijms19123710. [PMID: 30469514 PMCID: PMC6321563 DOI: 10.3390/ijms19123710] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/18/2018] [Accepted: 11/19/2018] [Indexed: 12/31/2022] Open
Abstract
The angiosperm pollen tube delivers two sperm cells into the embryo sac through a unique growth strategy, named tip growth, to accomplish fertilization. A great deal of experiments have demonstrated that actin bundles play a pivotal role in pollen tube tip growth. There are two distinct actin bundle populations in pollen tubes: the long, rather thick actin bundles in the shank and the short, highly dynamic bundles near the apex. With the development of imaging techniques over the last decade, great breakthroughs have been made in understanding the function of actin bundles in pollen tubes, especially short subapical actin bundles. Here, we tried to draw an overall picture of the architecture, functions and underlying regulation mechanism of actin bundles in plant pollen tubes.
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Affiliation(s)
- Shujuan Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Chunbo Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Min Xie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Jinyu Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Zhe Kong
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Hui Su
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
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19
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Pelaseyed T, Bretscher A. Regulation of actin-based apical structures on epithelial cells. J Cell Sci 2018; 131:131/20/jcs221853. [PMID: 30333133 DOI: 10.1242/jcs.221853] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cells of transporting epithelia are characterized by the presence of abundant F-actin-based microvilli on their apical surfaces. Likewise, auditory hair cells have highly reproducible rows of apical stereocilia (giant microvilli) that convert mechanical sound into an electrical signal. Analysis of mutations in deaf patients has highlighted the critical components of tip links between stereocilia, and related structures that contribute to the organization of microvilli on epithelial cells have been found. Ezrin/radixin/moesin (ERM) proteins, which are activated by phosphorylation, provide a critical link between the plasma membrane and underlying actin cytoskeleton in surface structures. Here, we outline recent insights into how microvilli and stereocilia are built, and the roles of tip links. Furthermore, we highlight how ezrin is locally regulated by phosphorylation, and that this is necessary to maintain polarity. Localized phosphorylation is achieved through an intricate coincidence detection mechanism that requires the membrane lipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and the apically localized ezrin kinase, lymphocyte-oriented kinase (LOK, also known as STK10) or Ste20-like kinase (SLK). We also discuss how ezrin-binding scaffolding proteins regulate microvilli and how, despite these significant advances, it remains to be discovered how the cell polarity program ultimately interfaces with these processes.
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Affiliation(s)
- Thaher Pelaseyed
- Institute of Biomedicine, Department of Medical Biochemistry and Cell Biology, University of Gothenburg, SE-405 30 Gothenburg, Sweden
| | - Anthony Bretscher
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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20
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McAlpine W, Wang KW, Choi JH, San Miguel M, McAlpine SG, Russell J, Ludwig S, Li X, Tang M, Zhan X, Choi M, Wang T, Bu CH, Murray AR, Moresco EMY, Turer EE, Beutler B. The class I myosin MYO1D binds to lipid and protects against colitis. Dis Model Mech 2018; 11:11/9/dmm035923. [PMID: 30279225 PMCID: PMC6176994 DOI: 10.1242/dmm.035923] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 08/02/2018] [Indexed: 12/12/2022] Open
Abstract
Myosin ID (MYO1D) is a member of the class I myosin family. We screened 48,649 third generation (G3) germline mutant mice derived from N-ethyl-N-nitrosourea-mutagenized grandsires for intestinal homeostasis abnormalities after oral administration of dextran sodium sulfate (DSS). We found and validated mutations in Myo1d as a cause of increased susceptibility to DSS-induced colitis. MYO1D is produced in the intestinal epithelium, and the colitis phenotype is dependent on the nonhematopoietic compartment of the mouse. Moreover, MYO1D appears to couple cytoskeletal elements to lipid in an ATP-dependent manner. These findings demonstrate that MYO1D is needed to maintain epithelial integrity and protect against DSS-induced colitis. Summary: Using random germline mutagenesis and screening of mice, we determined that loss of MYO1D function in nonhematopoietic tissues renders mice susceptible to colitis induced by dextran sodium sulfate challenge.
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Affiliation(s)
- William McAlpine
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Kuan-Wen Wang
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Jin Huk Choi
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Miguel San Miguel
- Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505 USA
| | - Sarah Grace McAlpine
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Jamie Russell
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Sara Ludwig
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Xiaohong Li
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Miao Tang
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Xiaoming Zhan
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Mihwa Choi
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Tao Wang
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA.,Quantitative Biomedical Research Center, Department of Clinical Science, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Chun Hui Bu
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Anne R Murray
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Eva Marie Y Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
| | - Emre E Turer
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA.,Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505 USA
| | - Bruce Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505, USA
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21
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Schneeberger K, Roth S, Nieuwenhuis EES, Middendorp S. Intestinal epithelial cell polarity defects in disease: lessons from microvillus inclusion disease. Dis Model Mech 2018; 11:11/2/dmm031088. [PMID: 29590640 PMCID: PMC5894939 DOI: 10.1242/dmm.031088] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The intestinal epithelium is a highly organized tissue. The establishment of epithelial cell polarity, with distinct apical and basolateral plasma membrane domains, is pivotal for both barrier formation and for the uptake and vectorial transport of nutrients. The establishment of cell polarity requires a specialized subcellular machinery to transport and recycle proteins to their appropriate location. In order to understand and treat polarity-associated diseases, it is necessary to understand epithelial cell-specific trafficking mechanisms. In this Review, we focus on cell polarity in the adult mammalian intestine. We discuss how intestinal epithelial polarity is established and maintained, and how disturbances in the trafficking machinery can lead to a polarity-associated disorder, microvillus inclusion disease (MVID). Furthermore, we discuss the recent developments in studying MVID, including the creation of genetically manipulated cell lines, mouse models and intestinal organoids, and their uses in basic and applied research. Summary: Microvillus inclusion disease serves as a useful model to enhance our understanding of the intestinal trafficking and polarity machinery in health and disease.
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Affiliation(s)
- Kerstin Schneeberger
- Division of Paediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, 3584 CT, Utrecht, The Netherlands
| | - Sabrina Roth
- Division of Paediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, 3584 CT, Utrecht, The Netherlands
| | - Edward E S Nieuwenhuis
- Division of Paediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, 3584 CT, Utrecht, The Netherlands
| | - Sabine Middendorp
- Division of Paediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, 3584 CT, Utrecht, The Netherlands .,Regenerative Medicine Center Utrecht, University Medical Centre (UMC) Utrecht, 3584 CT, Utrecht, The Netherlands
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22
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Franz J, Grünebaum J, Schäfer M, Mulac D, Rehfeldt F, Langer K, Kramer A, Riethmüller C. Rhombic organization of microvilli domains found in a cell model of the human intestine. PLoS One 2018; 13:e0189970. [PMID: 29320535 PMCID: PMC5761853 DOI: 10.1371/journal.pone.0189970] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 12/05/2017] [Indexed: 01/22/2023] Open
Abstract
Symmetry is rarely found on cellular surfaces. An exception is the brush border of microvilli, which are essential for the proper function of transport epithelia. In a healthy intestine, they appear densely packed as a 2D-hexagonal lattice. For in vitro testing of intestinal transport the cell line Caco-2 has been established. As reported by electron microscopy, their microvilli arrange primarily in clusters developing secondly into a 2D-hexagonal lattice. Here, atomic force microscopy (AFM) was employed under aqueous buffer conditions on Caco-2 cells, which were cultivated on permeable filter membranes for optimum differentiation. For analysis, the exact position of each microvillus was detected by computer vision; subsequent Fourier transformation yielded the type of 2D-lattice. It was confirmed, that Caco-2 cells can build a hexagonal lattice of microvilli and form clusters. Moreover, a second type of arrangement was discovered, namely a rhombic lattice, which appeared at sub-maximal densities of microvilli with (29 ± 4) microvilli / μm2. Altogether, the findings indicate the existence of a yet undescribed pattern in cellular organization.
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Affiliation(s)
- Jonas Franz
- Faculty of Physics, Georg-August-Universität, Göttingen, Germany
- Max Planck Institute for Dynamics and Self-Organization, Theoretical Neurophysics, Göttingen, Germany
| | - Jonas Grünebaum
- Institute for Pharmaceutical Technology and Biopharmacy, University of Münster, Münster, Germany
| | - Marcus Schäfer
- nanoAnalytics GmbH, Centre for Nanotechnology, Münster, Germany
| | - Dennis Mulac
- Institute for Pharmaceutical Technology and Biopharmacy, University of Münster, Münster, Germany
| | - Florian Rehfeldt
- Third Institute of Physics—Biophysics, Georg-August-Universität, Göttingen, Germany
| | - Klaus Langer
- Institute for Pharmaceutical Technology and Biopharmacy, University of Münster, Münster, Germany
| | - Armin Kramer
- Serend-ip GmbH, Centre for Nanotechnology, Münster, Germany
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23
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Engevik AC, Goldenring JR. Trafficking Ion Transporters to the Apical Membrane of Polarized Intestinal Enterocytes. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a027979. [PMID: 28264818 DOI: 10.1101/cshperspect.a027979] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Epithelial cells lining the gastrointestinal tract require distinct apical and basolateral domains to function properly. Trafficking and insertion of enzymes and transporters into the apical brush border of intestinal epithelial cells is essential for effective digestion and absorption of nutrients. Specific critical ion transporters are delivered to the apical brush border to facilitate fluid and electrolyte uptake. Maintenance of these apical transporters requires both targeted delivery and regulated membrane recycling. Examination of altered apical trafficking in patients with Microvillus Inclusion disease caused by inactivating mutations in MYO5B has led to insights into the regulation of apical trafficking by elements of the apical recycling system. Modeling of MYO5B loss in cell culture and animal models has led to recognition of Rab11a and Rab8a as critical regulators of apical brush border function. All of these studies show the importance of apical membrane trafficking dynamics in maintenance of polarized epithelial cell function.
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Affiliation(s)
- Amy Christine Engevik
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232.,Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - James R Goldenring
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232.,Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232.,Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37232.,Nashville VA Medical Center, Nashville, Tennessee 37232
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24
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Chandra S, Kalaivani R, Kumar M, Srinivasan N, Sarkar DP. Sendai virus recruits cellular villin to remodel actin cytoskeleton during fusion with hepatocytes. Mol Biol Cell 2017; 28:3801-3814. [PMID: 29074568 PMCID: PMC5739296 DOI: 10.1091/mbc.e17-06-0400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 10/10/2017] [Accepted: 10/20/2017] [Indexed: 01/23/2023] Open
Abstract
Reconstituted Sendai viral envelopes (virosomes) are well recognized for their promising potential in membrane fusion-mediated delivery of bioactive molecules to liver cells. Despite the known function of viral envelope glycoproteins in catalyzing fusion with cellular membrane, the role of host cell proteins remains elusive. Here, we used two-dimensional differential in-gel electrophoresis to analyze hepatic cells in early response to virosome-induced membrane fusion. Quantitative mass spectrometry together with biochemical analysis revealed that villin, an actin-modifying protein, is differentially up-regulated and phosphorylated at threonine 206-an early molecular event during membrane fusion. We found that villin influences actin dynamics and that this influence, in turn, promotes membrane mixing through active participation of Sendai viral envelope glycoproteins. Modulation of villin in host cells also resulted in a discernible effect on the entry and egress of progeny Sendai virus. Taken together, these results suggest a novel mechanism of regulated viral entry in animal cells mediated by host factor villin.
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Affiliation(s)
- Sunandini Chandra
- Department of Biochemistry, University of Delhi, New Delhi 110021, India
| | - Raju Kalaivani
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
- MRC Laboratory of Molecular Biology, Cambridge CB20QH, UK
| | - Manoj Kumar
- Department of Biochemistry, University of Delhi, New Delhi 110021, India
| | | | - Debi P Sarkar
- Department of Biochemistry, University of Delhi, New Delhi 110021, India
- Indian Institute of Science Education and Research, Mohali, Manauli PO 140306, Punjab, India
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25
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Oral administration of Bifidobacterium bifidum G9-1 alleviates rotavirus gastroenteritis through regulation of intestinal homeostasis by inducing mucosal protective factors. PLoS One 2017; 12:e0173979. [PMID: 28346473 PMCID: PMC5367788 DOI: 10.1371/journal.pone.0173979] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 03/01/2017] [Indexed: 12/17/2022] Open
Abstract
Human rotavirus (RV) infection is a leading cause of dehydrating diarrhea in infants and young children worldwide. Since therapeutic approaches to RV gastroenteritis are limited to alleviation of dehydration with oral rehydration solutions, more direct approaches to palliate symptoms of RV gastroenteritis are required. Treatments with probiotics have been increasingly recognized as alternative safe and low cost treatments for moderate infectious diarrhea. In this study, Bifidobacterium bifidum G9-1 (BBG9-1), which has been used as an intestinal drug for several decades, was shown to have a remarkable protective effect against RV gastroenteritis in a suckling mice model. As well as prophylactic oral administration of BBG9-1 from 2 days before RV infection, therapeutic oral administration of BBG9-1 from 1 day after RV infection significantly alleviated RV-induced diarrhea. Therapeutic administration of BBG9-1 reduced various types of damage in the small intestine, such as epithelial vacuolization and villous shortening, and significantly diminished the infectious RV titer in mixtures of cecal contents and feces. It was also shown that therapeutic administration of BBG9-1 significantly increased the number of acidic mucin-positive goblet cells and the gene expression of mucosal protective factors including MUC2, MUC3, MUC4, TGFβ1 and TFF3 in the small intestine. This led to alleviation of low gut permeability shown as decreased gene expression levels of occludin, claudin-1 and villin-1 after RV infection. Furthermore, in the small intestine, therapeutic administration of BBG9-1 significantly palliated the decreased gene expression of SGLT-1, which plays an important role in water absorption. In the large intestine, administered BBG9-1 was shown to replicate to assimilate undigested nutrients, resulting in normalization of the abnormally high osmotic pressure. These results suggested that water malabsorption caused by RV infection was alleviated in mice administered BBG9-1. Thus, the present study showed that oral administration of BBG9-1 palliated diarrhea partly through protection against RV-induced lesions by inducing mucosal protective factors. Oral administration of BBG9-1 is thought to be an efficient method for management of an RV epidemic for both prophylactic and therapeutic purposes.
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26
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Abstract
The vertebrate small intestine requires an enormous surface area to effectively absorb nutrients from food. Morphological adaptations required to establish this extensive surface include generation of an extremely long tube and convolution of the absorptive surface of the tube into villi and microvilli. In this Review, we discuss recent findings regarding the morphogenetic and molecular processes required for intestinal tube elongation and surface convolution, examine shared and unique aspects of these processes in different species, relate these processes to known human maladies that compromise absorptive function and highlight important questions for future research.
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Affiliation(s)
- Katherine D Walton
- Cell and Developmental Biology Department, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Andrew M Freddo
- Cell and Developmental Biology Department, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Sha Wang
- Cell and Developmental Biology Department, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Deborah L Gumucio
- Cell and Developmental Biology Department, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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27
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Mziaut H, Mulligan B, Hoboth P, Otto O, Ivanova A, Herbig M, Schumann D, Hildebrandt T, Dehghany J, Sönmez A, Münster C, Meyer-Hermann M, Guck J, Kalaidzidis Y, Solimena M. The F-actin modifier villin regulates insulin granule dynamics and exocytosis downstream of islet cell autoantigen 512. Mol Metab 2016; 5:656-668. [PMID: 27656403 PMCID: PMC5021679 DOI: 10.1016/j.molmet.2016.05.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 05/20/2016] [Accepted: 05/24/2016] [Indexed: 01/02/2023] Open
Abstract
Objective Insulin release from pancreatic islet β cells should be tightly controlled to avoid hypoglycemia and insulin resistance. The cortical actin cytoskeleton is a gate for regulated exocytosis of insulin secretory granules (SGs) by restricting their mobility and access to the plasma membrane. Prior studies suggest that SGs interact with F-actin through their transmembrane cargo islet cell autoantigen 512 (Ica512) (also known as islet antigen 2/Ptprn). Here we investigated how Ica512 modulates SG trafficking and exocytosis. Methods Transcriptomic changes in Ica512−/− mouse islets were analyzed. Imaging as well as biophysical and biochemical methods were used to validate if and how the Ica512-regulated gene villin modulates insulin secretion in mouse islets and insulinoma cells. Results The F-actin modifier villin was consistently downregulated in Ica512−/− mouse islets and in Ica512-depleted insulinoma cells. Villin was enriched at the cell cortex of β cells and dispersed villin−/− islet cells were less round and less deformable. Basal mobility of SGs in villin-depleted cells was enhanced. Moreover, in cells depleted either of villin or Ica512 F-actin cages restraining cortical SGs were enlarged, basal secretion was increased while glucose-stimulated insulin release was blunted. The latter changes were reverted by overexpressing villin in Ica512-depleted cells, but not vice versa. Conclusion Our findings show that villin controls the size of the F-actin cages restricting SGs and, thus, regulates their dynamics and availability for exocytosis. Evidence that villin acts downstream of Ica512 also indicates that SGs directly influence the remodeling properties of the cortical actin cytoskeleton for tight control of insulin secretion. Ica512-depletion reduces the genetic expression of the F-actin modifier villin. Villin-depletion enhances basal insulin granule mobility and exocytosis. Villin regulates the size of actin cages restraining insulin granules. Villin acts downstream of insulin granule cargo Ica512. The Ica512-villin genetic link enables granules to control cytoskeleton plasticity.
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Key Words
- D, diffusion coefficient
- EGFP, enhanced green fluorescent protein
- F-actin
- Granules
- IPGTT, intraperitoneal glucose tolerance test
- IVGTT, intravenous glucose tolerance test
- Ica512
- Ica512, islet cell autoantigen
- Insulin
- OGTT, oral glucose tolerance test
- RT-DC, real-time deformability cytometry
- SE, standard error
- SG, secretory granules
- Secretion
- TIRFM, total internal reflection fluorescence microscopy
- Villin
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Affiliation(s)
- Hassan Mziaut
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the Univ. Hospital, Faculty of Medicine Carl Gustav Carus, Technische Univ. Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85674 Neuherberg, Germany
| | - Bernard Mulligan
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the Univ. Hospital, Faculty of Medicine Carl Gustav Carus, Technische Univ. Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85674 Neuherberg, Germany
| | - Peter Hoboth
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the Univ. Hospital, Faculty of Medicine Carl Gustav Carus, Technische Univ. Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85674 Neuherberg, Germany
| | - Oliver Otto
- Biotechnology Center Dresden, 01307 Dresden, Germany
| | - Anna Ivanova
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the Univ. Hospital, Faculty of Medicine Carl Gustav Carus, Technische Univ. Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85674 Neuherberg, Germany
| | - Maik Herbig
- Biotechnology Center Dresden, 01307 Dresden, Germany
| | - Desiree Schumann
- Boehringer Ingelheim Pharma GmbH & Co. KG. Cardiometabolic Research, 88397 Biberach, Germany
| | - Tobias Hildebrandt
- Boehringer Ingelheim Pharma GmbH & Co. KG. Cardiometabolic Research, 88397 Biberach, Germany
| | - Jaber Dehghany
- Helmholtz Centre for Infection Research (HZI), Braunschweig Integrated Centre for Systems Biology (BRICS), 38124 Braunschweig, Germany
| | - Anke Sönmez
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the Univ. Hospital, Faculty of Medicine Carl Gustav Carus, Technische Univ. Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85674 Neuherberg, Germany
| | - Carla Münster
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the Univ. Hospital, Faculty of Medicine Carl Gustav Carus, Technische Univ. Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85674 Neuherberg, Germany
| | - Michael Meyer-Hermann
- Helmholtz Centre for Infection Research (HZI), Braunschweig Integrated Centre for Systems Biology (BRICS), 38124 Braunschweig, Germany
| | - Jochen Guck
- Biotechnology Center Dresden, 01307 Dresden, Germany
| | - Yannis Kalaidzidis
- Max Planck Institute for Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Michele Solimena
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the Univ. Hospital, Faculty of Medicine Carl Gustav Carus, Technische Univ. Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85674 Neuherberg, Germany; Max Planck Institute for Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
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28
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Hegan PS, Chandhoke SK, Barone C, Egan M, Bähler M, Mooseker MS. Mice lacking myosin IXb, an inflammatory bowel disease susceptibility gene, have impaired intestinal barrier function and superficial ulceration in the ileum. Cytoskeleton (Hoboken) 2016; 73:163-79. [PMID: 26972322 DOI: 10.1002/cm.21292] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 12/16/2022]
Abstract
Genetic studies have implicated MYO9B, which encodes myosin IXb (Myo9b), a motor protein with a Rho GTPase activating domain (RhoGAP), as a susceptibility gene for inflammatory bowel disease (IBD). Moreover, we have recently shown that knockdown of Myo9b in an intestinal epithelial cell line impairs wound healing and barrier function. Here, we investigated whether mice lacking Myo9b have impaired intestinal barrier function and features of IBD. Myo9b knock out (KO) mice exhibit impaired weight gain and fecal occult blood (indicator of gastrointestinal bleeding), and increased intestinal epithelial cell apoptosis could be detected along the entire intestinal axis. Histologic analysis revealed intestinal mucosal damage, most consistently observed in the ileum, which included superficial ulceration and neutrophil infiltration. Focal lesions contained neutrophils and ultrastructural examination confirmed epithelial discontinuity and the deposition of extracellular matrix. We also observed impaired mucosal barrier function in KO mice. Transepithelial electrical resistance of KO ileum is >3 fold less than WT ileum. The intestinal mucosa is also permeable to high molecular weight dextran, presumably due to the presence of mucosal surface ulcerations. There is loss of tight junction-associated ZO-1, decreased lateral membrane associated E-cadherin, and loss of terminal web associated cytokeratin filaments. Consistent with increased Rho activity in the KO, there is increased subapical expression of activated myosin II (Myo2) based on localization of phosphorylated Myo2 regulatory light chain. Except for a delay in disease onset in the KO, no difference in dextran sulfate sodium-induced colitis and lethality was observed between wild-type and Myo9b KO mice.
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Affiliation(s)
- Peter S Hegan
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut
| | - Surjit K Chandhoke
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut
| | - Christina Barone
- Department of Respiratory Medicine, Yale School of Medicine, New Haven, Connecticut
| | - Marie Egan
- Department of Respiratory Medicine, Yale School of Medicine, New Haven, Connecticut
| | - Martin Bähler
- Institute of Molecular Cell Biology, Westfalian Wilhelms University, Münster, Germany
| | - Mark S Mooseker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut.,Departments of Cell Biology and Pathology, Yale School of Medicine, New Haven, Connecticut
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29
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Abstract
The brush border on the apical surface of enterocytes is a highly specialized structure well-adapted for efficient digestion and nutrient transport, whilst at the same time providing a protective barrier for the intestinal mucosa. The brush border is constituted of a densely ordered array of microvilli, protrusions of the plasma membrane, which are supported by actin-based microfilaments and interacting proteins and anchored in an apical network of actomyosin and intermediate filaments, the so-called terminal web. The highly dynamic, specialized apical domain is both an essential partner for the gut microbiota and an efficient signalling platform that enables adaptation to physiological stimuli from the external and internal milieu. Nevertheless, genetic alterations or various pathological stresses, such as infection, inflammation, and mechanical or nutritional alterations, can jeopardize this equilibrium and compromise intestinal functions. Long-time neglected, the intestinal brush-border shall be enlightening again as the central actor of the complex but essential intestinal homeostasis. Here, we review the processes and components involved in brush border organization and discuss pathological mechanisms that can induce brush border defects and their physiological consequences.
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30
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Stradal TEB, Costa SCP. Type III Secreted Virulence Factors Manipulating Signaling to Actin Dynamics. Curr Top Microbiol Immunol 2016; 399:175-199. [PMID: 27744505 DOI: 10.1007/82_2016_35] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A key aspect of bacterial pathogenesis is the colonization and persistence within the host and, later on, its dissemination to new niches. During evolution, bacteria developed a myriad of virulence mechanisms to usurp the host's sophisticated defense mechanisms in order to establish their colonization niche. Elucidation of the highly dynamic and complex interactions between host and pathogens remains an important field of study. Here, we highlight the conserved manipulation of the actin cytoskeleton by some Gram-negative gastrointestinal pathogens, addressing the role of type III secreted bacterial GEFs at the different steps of pathogenesis. As a final topic, we review cytoskeleton dynamics induced by EPEC/EHEC strains for pedestal formation.
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Affiliation(s)
- Theresia E B Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Baunschweig, Germany.
| | - Sonia C P Costa
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Baunschweig, Germany
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31
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Patnaik S, George SP, Pham E, Roy S, Singh K, Mariadason JM, Khurana S. By moonlighting in the nucleus, villin regulates epithelial plasticity. Mol Biol Cell 2015; 27:535-48. [PMID: 26658611 PMCID: PMC4751603 DOI: 10.1091/mbc.e15-06-0453] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 11/30/2015] [Indexed: 12/02/2022] Open
Abstract
Nuclear villin regulates the expression and activity of Slug, a key transcriptional regulator of epithelial–mesenchymal transition, by directly interacting with its transcriptional corepressor, ZBRK1. Villin accumulates in the nucleus during wound repair, and altering the cellular microenvironment by hypoxia increases the nuclear villin. Villin is a tissue-specific, actin-binding protein involved in the assembly and maintenance of microvilli in polarized epithelial cells. Conversely, villin is also linked with the loss of epithelial polarity and gain of the mesenchymal phenotype in migrating, invasive cells. In this study, we describe for the first time how villin can switch between these disparate functions to change tissue architecture by moonlighting in the nucleus. Our study reveals that the moonlighting function of villin in the nucleus may play an important role in tissue homeostasis and disease. Villin accumulates in the nucleus during wound repair, and altering the cellular microenvironment by inducing hypoxia increases the nuclear accumulation of villin. Nuclear villin is also associated with mouse models of tumorigenesis, and a systematic analysis of a large cohort of colorectal cancer specimens confirmed the nuclear distribution of villin in a subset of tumors. Our study demonstrates that nuclear villin regulates epithelial–mesenchymal transition (EMT). Altering the nuclear localization of villin affects the expression and activity of Slug, a key transcriptional regulator of EMT. In addition, we find that villin directly interacts with a transcriptional corepressor and ligand of the Slug promoter, ZBRK1. The outcome of this study underscores the role of nuclear villin and its binding partner ZBRK1 in the regulation of EMT and as potential new therapeutic targets to inhibit tumorigenesis.
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Affiliation(s)
- Srinivas Patnaik
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - Sudeep P George
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - Eric Pham
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - Swati Roy
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - Kanchan Singh
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204
| | - John M Mariadason
- Olivia Newton-John Cancer Research Institute, La Trobe University School of Cancer Medicine, Melbourne, VIC 3084, Australia
| | - Seema Khurana
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204 Baylor College of Medicine, Houston, TX 77030
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32
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Sauvanet C, Wayt J, Pelaseyed T, Bretscher A. Structure, Regulation, and Functional Diversity of Microvilli on the Apical Domain of Epithelial Cells. Annu Rev Cell Dev Biol 2015; 31:593-621. [DOI: 10.1146/annurev-cellbio-100814-125234] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Cécile Sauvanet
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
| | - Jessica Wayt
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
| | - Thaher Pelaseyed
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
| | - Anthony Bretscher
- Department of Molecular Biology and Genetics and Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, New York 14853;
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33
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Cell protrusions induced by hyaluronan synthase 3 (HAS3) resemble mesothelial microvilli and share cytoskeletal features of filopodia. Exp Cell Res 2015; 337:179-91. [DOI: 10.1016/j.yexcr.2015.06.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 06/18/2015] [Accepted: 06/20/2015] [Indexed: 01/04/2023]
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Hegan PS, Kravtsov DV, Caputo C, Egan ME, Ameen NA, Mooseker MS. Restoration of cytoskeletal and membrane tethering defects but not defects in membrane trafficking in the intestinal brush border of mice lacking both myosin Ia and myosin VI. Cytoskeleton (Hoboken) 2015; 72:455-76. [PMID: 26286357 PMCID: PMC4715533 DOI: 10.1002/cm.21238] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/11/2015] [Accepted: 08/12/2015] [Indexed: 12/22/2022]
Abstract
Myosin Ia (Myo1a), the most prominent plus-end directed motor and myosin VI (Myo6) the sole minus-end directed motor, together exert opposing tension between the microvillar (MV) actin core and the apical brush border (BB) membrane of the intestinal epithelial cell (IEC). Mice lacking Myo1a or Myo6 each exhibit a variety of defects in the tethering of the BB membrane to the actin cytoskeleton. Double mutant (DM) mice lacking both myosins revealed that all the defects observed in either the Myo1a KO or Snell's waltzer (sv/sv) Myo6 mutant mouse are absent. In isolated DM BBs, Myo1a crosslinks between MV membrane and MV actin core are absent but the gap (which is lost in Myo1a KO) between the MV core and membrane is maintained. Several myosins including Myo1c, d, and e and Myo5a are ectopically recruited to the BB. Consistent with the restoration of membrane tethering defects by one or more of these myosins, upward ATP-driven shedding of the BB membrane, which is blocked in the Myo1a KO, is restored in the DM BB. However, Myo1a or Myo6 dependent defects in expression of membrane proteins that traffic between the BB membrane and endosome (NaPi2b, NHE3, CFTR) are not restored. Compared to controls, Myo1a KO, sv/sv mice exhibit moderate and DM high levels of hypersensitivity to dextran sulfate sodium-induced colitis. Consistent with Myo1a and Myo6 playing critical roles in maintaining IEC integrity and response to injury, DM IECs exhibit increased numbers of apoptotic nuclei, above that reported for Myo1a KO.
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Affiliation(s)
- Peter S Hegan
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut
| | - Dmitri V Kravtsov
- Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, New Haven, Connecticut
| | - Christina Caputo
- Department of Respiratory Medicine, Yale School of Medicine, New Haven, Connecticut
| | - Marie E Egan
- Department of Respiratory Medicine, Yale School of Medicine, New Haven, Connecticut
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| | - Nadia A Ameen
- Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, New Haven, Connecticut
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| | - Mark S Mooseker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut
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Abstract
Epithelial cells from diverse tissues, including the enterocytes that line the intestinal tract, remodel their apical surface during differentiation to form a brush border: an array of actin-supported membrane protrusions known as microvilli that increases the functional capacity of the tissue. Although our understanding of how epithelial cells assemble, stabilize, and organize apical microvilli is still developing, investigations of the biochemical and physical underpinnings of these processes suggest that cells coordinate cytoskeletal remodeling, membrane-cytoskeleton cross-linking, and extracellular adhesion to shape the apical brush border domain.
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Affiliation(s)
- Scott W Crawley
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Mark S Mooseker
- Department of Molecular, Cellular and Developmental Biology, Department of Cell Biology, and Department of Pathology, Yale University, New Haven, CT 06520 Department of Molecular, Cellular and Developmental Biology, Department of Cell Biology, and Department of Pathology, Yale University, New Haven, CT 06520 Department of Molecular, Cellular and Developmental Biology, Department of Cell Biology, and Department of Pathology, Yale University, New Haven, CT 06520
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232
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Lhocine N, Arena ET, Bomme P, Ubelmann F, Prévost MC, Robine S, Sansonetti PJ. Apical invasion of intestinal epithelial cells by Salmonella typhimurium requires villin to remodel the brush border actin cytoskeleton. Cell Host Microbe 2015; 17:164-77. [PMID: 25600187 PMCID: PMC4346658 DOI: 10.1016/j.chom.2014.12.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 09/16/2014] [Accepted: 12/04/2014] [Indexed: 01/16/2023]
Abstract
Salmonella invasion of intestinal epithelial cells requires extensive, though transient, actin modifications at the site of bacterial entry. The actin-modifying protein villin is present in the brush border where it participates in the constitution of microvilli and in epithelial restitution after damage through its actin-severing activity. We investigated a possible role for villin in Salmonella invasion. The absence of villin, which is normally located at the bacterial entry site, leads to a decrease in Salmonella invasion. Villin is necessary for early membrane-associated processes and for optimal ruffle assembly by balancing the steady-state level of actin. The severing activity of villin is important for Salmonella invasion in vivo. The bacterial phosphatase SptP tightly regulates villin phosphorylation, while the actin-binding effector SipA protects F-actin and counterbalances villin-severing activity. Thus, villin plays an important role in establishing the balance between actin polymerization and actin severing to facilitate the initial steps of Salmonella entry. The host actin-binding protein villin is required for Salmonella apical invasion Villin plays a role in Salmonella ruffle formation and actin dynamics Villin-severing activity promotes Salmonella invasion in cells and in vivo The bacterial effectors SipA and SptP regulate villin activities
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Affiliation(s)
- Nouara Lhocine
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France; INSERM U786, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France
| | - Ellen T Arena
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France; INSERM U786, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France
| | - Perrine Bomme
- Plateforme de Microscopie Ultrastructurale, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France
| | - Florent Ubelmann
- Unité Mixte de Recherche 144, Institut Curie, 75248 Paris Cedex 05, France; Centro de Estudos de Doenças Crónicas (CEDOC), Faculdade de Ciencias Médicas, Universidade Nova de Lisboa, 1169-056, Portugal
| | - Marie-Christine Prévost
- Plateforme de Microscopie Ultrastructurale, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France
| | - Sylvie Robine
- Unité Mixte de Recherche 144, Institut Curie, 75248 Paris Cedex 05, France
| | - Philippe J Sansonetti
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France; INSERM U786, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France; Collège de France, 11 Place Marcelin Berthelot, 75005 Paris, France.
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Blasche S, Arens S, Ceol A, Siszler G, Schmidt MA, Häuser R, Schwarz F, Wuchty S, Aloy P, Uetz P, Stradal T, Koegl M. The EHEC-host interactome reveals novel targets for the translocated intimin receptor. Sci Rep 2014; 4:7531. [PMID: 25519916 PMCID: PMC4269881 DOI: 10.1038/srep07531] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 11/21/2014] [Indexed: 12/20/2022] Open
Abstract
Enterohemorrhagic E. coli (EHEC) manipulate their human host through at least 39 effector proteins which hijack host processes through direct protein-protein interactions (PPIs). To identify their protein targets in the host cells, we performed yeast two-hybrid screens, allowing us to find 48 high-confidence protein-protein interactions between 15 EHEC effectors and 47 human host proteins. In comparison to other bacteria and viruses we found that EHEC effectors bind more frequently to hub proteins as well as to proteins that participate in a higher number of protein complexes. The data set includes six new interactions that involve the translocated intimin receptor (TIR), namely HPCAL1, HPCAL4, NCALD, ARRB1, PDE6D, and STK16. We compared these TIR interactions in EHEC and enteropathogenic E. coli (EPEC) and found that five interactions were conserved. Notably, the conserved interactions included those of serine/threonine kinase 16 (STK16), hippocalcin-like 1 (HPCAL1) as well as neurocalcin-delta (NCALD). These proteins co-localize with the infection sites of EPEC. Furthermore, our results suggest putative functions of poorly characterized effectors (EspJ, EspY1). In particular, we observed that EspJ is connected to the microtubule system while EspY1 appears to be involved in apoptosis/cell cycle regulation.
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Affiliation(s)
- Sonja Blasche
- Genomics and Proteomics Core Facilities, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Stefan Arens
- Institute of Molecular Cell Biology, University of Münster, Schlossplatz 5, D-48149 Münster
| | - Arnaud Ceol
- 1] Joint IRB-BSC Program in Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain [2] Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia (IIT), Via Adamello 16, 20139 Milan - Italy
| | - Gabriella Siszler
- Genomics and Proteomics Core Facilities, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - M Alexander Schmidt
- Institute of Infectiology, ZMBE, University of Münster, Von-Esmarch-Str. 56, D-48149 Münster
| | - Roman Häuser
- Genomics and Proteomics Core Facilities, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Frank Schwarz
- Genomics and Proteomics Core Facilities, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Stefan Wuchty
- 1] Dept. of Computer Science, Univ. of Miami, 1365 Memorial Drive, Coral Gables, FL 33146, USA [2] Center for Computational Science, Univ. of Miami, 1365 Memorial Drive, Coral Gables, FL 33146, USA
| | - Patrick Aloy
- 1] Joint IRB-BSC Program in Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain [2] Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Peter Uetz
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Theresia Stradal
- 1] Institute of Molecular Cell Biology, University of Münster, Schlossplatz 5, D-48149 Münster [2] Helmholtz Centre for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig
| | - Manfred Koegl
- Genomics and Proteomics Core Facilities, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
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Crawley SW, Shifrin DA, Grega-Larson NE, McConnell RE, Benesh AE, Mao S, Zheng Y, Zheng QY, Nam KT, Millis BA, Kachar B, Tyska MJ. Intestinal brush border assembly driven by protocadherin-based intermicrovillar adhesion. Cell 2014; 157:433-446. [PMID: 24725409 DOI: 10.1016/j.cell.2014.01.067] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 12/19/2013] [Accepted: 01/28/2014] [Indexed: 12/17/2022]
Abstract
Transporting epithelial cells build apical microvilli to increase membrane surface area and enhance absorptive capacity. The intestinal brush border provides an elaborate example with tightly packed microvilli that function in nutrient absorption and host defense. Although the brush border is essential for physiological homeostasis, its assembly is poorly understood. We found that brush border assembly is driven by the formation of Ca(2+)-dependent adhesion links between adjacent microvilli. Intermicrovillar links are composed of protocadherin-24 and mucin-like protocadherin, which target to microvillar tips and interact to form a trans-heterophilic complex. The cytoplasmic domains of microvillar protocadherins interact with the scaffolding protein, harmonin, and myosin-7b, which promote localization to microvillar tips. Finally, a mouse model of Usher syndrome lacking harmonin exhibits microvillar protocadherin mislocalization and severe defects in brush border morphology. These data reveal an adhesion-based mechanism for brush border assembly and illuminate the basis of intestinal pathology in patients with Usher syndrome. PAPERFLICK:
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Affiliation(s)
- Scott W Crawley
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - David A Shifrin
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Nathan E Grega-Larson
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Russell E McConnell
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Andrew E Benesh
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Suli Mao
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Yuxi Zheng
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Qing Yin Zheng
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ki Taek Nam
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
| | - Bryan A Millis
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bechara Kachar
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Parlato M, Yeretssian G. NOD-like receptors in intestinal homeostasis and epithelial tissue repair. Int J Mol Sci 2014; 15:9594-627. [PMID: 24886810 PMCID: PMC4100112 DOI: 10.3390/ijms15069594] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/16/2014] [Accepted: 05/20/2014] [Indexed: 12/13/2022] Open
Abstract
The intestinal epithelium constitutes a dynamic physical barrier segregating the luminal content from the underlying mucosal tissue. Following injury, the epithelial integrity is restored by rapid migration of intestinal epithelial cells (IECs) across the denuded area in a process known as wound healing. Hence, through a sequence of events involving restitution, proliferation and differentiation of IECs the gap is resealed and homeostasis reestablished. Relapsing damage followed by healing of the inflamed mucosa is a hallmark of several intestinal disorders including inflammatory bowel diseases (IBD). While several regulatory peptides, growth factors and cytokines stimulate restitution of the epithelial layer after injury, recent evidence in the field underscores the contribution of innate immunity in controlling this process. In particular, nucleotide-binding and oligomerization domain-like receptors (NLRs) play critical roles in sensing the commensal microbiota, maintaining homeostasis, and regulating intestinal inflammation. Here, we review the process of intestinal epithelial tissue repair and we specifically focus on the impact of NLR-mediated signaling mechanisms involved in governing epithelial wound healing during disease.
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Affiliation(s)
- Marianna Parlato
- Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Garabet Yeretssian
- Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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40
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Food grade titanium dioxide disrupts intestinal brush border microvilli in vitro independent of sedimentation. Cell Biol Toxicol 2014; 30:169-88. [PMID: 24817113 DOI: 10.1007/s10565-014-9278-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 04/17/2014] [Indexed: 12/22/2022]
Abstract
Bulk- and nano-scale titanium dioxide (TiO2) has found use in human food products for controlling color, texture, and moisture. Once ingested, and because of their small size, nano-scale TiO2 can interact with a number of epithelia that line the human gastrointestinal tract. One such epithelium responsible for nutrient absorption is the small intestine, whose constituent cells contain microvilli to increase the total surface area of the gut. Using a combination of scanning and transmission electron microscopy it was found that food grade TiO2 (E171 food additive coded) included ∼25% of the TiO2 as nanoparticles (NPs; <100 nm), and disrupted the normal organization of the microvilli as a consequence of TiO2 sedimentation. It was found that TiO2 isolated from the candy coating of chewing gum and a commercially available TiO2 food grade additive samples were of the anatase crystal structure. Exposure to food grade TiO2 additives, containing nanoparticles, at the lowest concentration tested within this experimental paradigm to date at 350 ng/mL (i.e., 100 ng/cm(2) cell surface area) resulted in disruption of the brush border. Through the use of two independent techniques to remove the effects of gravity, and subsequent TiO2 sedimentation, it was found that disruption of the microvilli was independent of sedimentation. These data indicate that food grade TiO2 exposure resulted in the loss of microvilli from the Caco-2BBe1 cell system due to a biological response, and not simply a physical artifact of in vitro exposure.
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Thapsigargin induces apoptosis by impairing cytoskeleton dynamics in human lung adenocarcinoma cells. ScientificWorldJournal 2014; 2014:619050. [PMID: 24605059 PMCID: PMC3926280 DOI: 10.1155/2014/619050] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/10/2013] [Indexed: 12/31/2022] Open
Abstract
The objective of this study was performed to investigate the effects of thapsigargin on apoptosis, actin cytoskeletal dynamics, and actin cytoskeletal proteins in human lung adenocarcinoma cell. Thapsigargin is a specific irreversible inhibitor of ER calcium-ATPase, which may promote ER stress by depletion of lumenal calcium stores and show potential to induce cell death. The effects of thapsigargin on the apoptosis in A549 cells were assayed by Hoechst staining. Moreover, the F-actin staining by Rhodamine-phalloidin and RhoA antibody for cytoskeleton organizations were applied to A549 cells. To confirm the impairment of cytoskeletal dynamics treated with thapsigargin, western blots were applied to analyze the protein levels of p-Cofilin-1 (Ser3), Cofilin-1, and pPaxillin (Tyr118), as well as RhoA and pS6 (S240/244). Results suggest that thapsigargin may induce cell death in A549 cells with a time- and dose-dependent manner. The F-actin fibers and RhoA signals are also reduced with a time- and dose-dependent manner by thapsigargin treatment. The phosphorylation forms of Cofilin-1 and paxillin are attenuated by 1 μM thapsigargin treatment for 24 h. These alternations may be caused by the inhibition of of mTORC1 activities (indicated by pS6 (Ser240/244)) and RhoA pathways after thapsigargin treatment. The present findings highlight important roles of calcium entry in cytoskeleton organization and apoptosis in human lung adenocarcinoma cells and will help to set a stage to the clinical treatment of cancer cell metastasis.
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Fedechkin SO, Brockerman J, Pfaff DA, Burns L, Webb T, Nelson A, Zhang F, Sabantsev AV, Melnikov AS, McKnight CJ, Smirnov SL. Gelsolin-like activation of villin: calcium sensitivity of the long helix in domain 6. Biochemistry 2013; 52:7890-900. [PMID: 24070253 DOI: 10.1021/bi400699s] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Villin is a gelsolin-like cytoskeleton regulator localized in the brush border at the apical end of epithelial cells. Villin regulates microvilli by bundling F-actin at low calcium levels and severing it at high calcium levels. The villin polypeptide consists of six gelsolin-like repeats (V1-V6) and the unique, actin binding C-terminal headpiece domain (HP). Villin modular fragment V6-HP requires calcium to stay monomeric and bundle F-actin. Our data show that isolated V6 is monomeric and does not bind F-actin at any level of calcium. We propose that the 40-residue unfolded V6-to-HP linker can be a key regulatory element in villin's functions such as its interactions with F-actin. Here we report a calcium-bound solution nuclear magnetic resonance (NMR) structure of V6, which has a gelsolin-like fold with the long α-helix in the extended conformation. Intrinsic tryptophan fluorescence quenching reveals two-Kd calcium binding in V6 (Kd1 of 22 μM and Kd2 of 2.8 mM). According to our NMR data, the conformation of V6 responds the most to micromolar calcium. We show that the long α-helix and the adjacent residues form the calcium-sensitive elements in V6. These observations are consistent with the calcium activation of F-actin severing by villin analogous to the gelsolin helix-straightening mechanism.
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Affiliation(s)
- Stanislav O Fedechkin
- Department of Chemistry, Western Washington University , 516 High Street, Bellingham, Washington 98225-9150, United States
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Enterocyte loss of polarity and gut wound healing rely upon the F-actin-severing function of villin. Proc Natl Acad Sci U S A 2013; 110:E1380-9. [PMID: 23520048 DOI: 10.1073/pnas.1218446110] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Efficient wound healing is required to maintain the integrity of the intestinal epithelial barrier because of its constant exposure to a large variety of environmental stresses. This process implies a partial cell depolarization and the acquisition of a motile phenotype that involves rearrangements of the actin cytoskeleton. Here we address how polarized enterocytes harboring actin-rich apical microvilli undergo extensive cell remodeling to drive injury repair. Using live imaging technologies, we demonstrate that enterocytes in vitro and in vivo rapidly depolarize their microvilli at the wound edge. Through its F-actin-severing activity, the microvillar actin-binding protein villin drives both apical microvilli disassembly in vitro and in vivo and promotes lamellipodial extension. Photoactivation experiments indicate that microvillar actin is mobilized at the lamellipodium, allowing optimal migration. Finally, efficient repair of colonic mechanical injuries requires villin severing of F-actin, emphasizing the importance of villin function in intestinal homeostasis. Thus, villin severs F-actin to ensure microvillus depolarization and enterocyte remodeling upon injury. This work highlights the importance of specialized apical pole disassembly for the repolarization of epithelial cells initiating migration.
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Wieschhaus AJ, Le Breton GC, Chishti AH. Headpiece domain of dematin regulates calcium mobilization and signaling in platelets. J Biol Chem 2012; 287:41218-31. [PMID: 23060452 DOI: 10.1074/jbc.m112.364679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dematin is a broadly expressed membrane cytoskeletal protein that has been well characterized in erythrocytes and to a lesser extent in non-erythroid cells. However, dematin's function in platelets is not known. Here, we show that dematin is abundantly expressed in both human and mouse platelets. Platelets harvested from the dematin headpiece knock-out (HPKO) mouse model exhibit a striking defect in the mobilization of calcium in response to multiple agonists of platelet activation. The reduced calcium mobilization in HPKO platelets is associated with concomitant inhibition of platelet aggregation and granule secretion. Integrin α(IIb)β(3) activation in response to agonists is attenuated in the HPKO platelets. The mutant platelets show nearly normal spreading on fibrinogen and an unaltered basal cAMP level; however, the clot retraction was compromised in the mutant mice. Immunofluorescence analysis indicated that dematin is present both at the dense tubular system and plasma membrane fractions of platelets. Proteomic analysis of dematin-associated proteins in human platelets identified inositol 1,4,5-trisphosphate 3-kinase isoform B (IP3KB) as a binding partner, which was confirmed by immunoprecipitation analysis. IP3KB, a dense tubular system protein, is a major regulator of calcium homeostasis. Loss of the dematin headpiece resulted in a decrease of IP3KB at the membrane and increased levels of IP3KB in the cytosol. Collectively, these findings unveil dematin as a novel regulator of internal calcium mobilization in platelets affecting multiple signaling and cytoskeletal functions. Implications of a conserved role of dematin in the regulation of calcium homeostasis in other cell types will be discussed.
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Affiliation(s)
- Adam J Wieschhaus
- Department of Molecular Physiology and Pharmacology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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45
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George SP, Chen H, Conrad JC, Khurana S. Regulation of directional cell migration by membrane-induced actin bundling. J Cell Sci 2012; 126:312-26. [PMID: 23132923 DOI: 10.1242/jcs.116244] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
During embryonic development and in metastatic cancers, cells detach from the epithelium and migrate with persistent directionality. Directional cell migration is also crucial for the regeneration and maintenance of the epithelium and impaired directional migration is linked to chronic inflammatory diseases. Despite its significance, the mechanisms controlling epithelial cell migration remain poorly understood. Villin is an epithelial-cell-specific actin modifying protein that regulates epithelial cell plasticity and motility. In motile cells villin is associated with the highly branched and the unbranched actin filaments of lamellipodia and filopodia, respectively. In this study we demonstrate for the first time that villin regulates directionally persistent epithelial cell migration. Functional characterization of wild-type and mutant villin proteins revealed that the ability of villin to self-associate and bundle actin as well as its direct interaction with phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P(2)] regulates villin-induced filopodial assembly and directional cell migration. Our findings suggest that convergence of different signaling cascades could spatially restrict villin activity to areas of high PtdIns(4,5)P(2) and F-actin concentration to assemble filopodia. Furthermore, our data reveal the ability of villin to undergo actin- and PtdIns(4,5)P(2)-induced self-association, which may be particularly suited to coalesce and reorganize actin bundles within the filopodia.
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Affiliation(s)
- Sudeep P George
- Department of Biology and Biochemistry, The University of Houston, Houston, TX 77204, USA
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46
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Mishra J, Karanki SS, Kumar N. Identification of molecular switch regulating interactions of Janus kinase 3 with cytoskeletal proteins. J Biol Chem 2012; 287:41386-91. [PMID: 23012362 DOI: 10.1074/jbc.c112.363507] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Janus kinase 3 (Jak3) is a nonreceptor tyrosine kinase expressed in both hematopoietic and nonhematopoietic cells. Although mutations that abrogate Jak3 functions cause different immunological disorders, its constitutive activation leads to various types of cancer. Previously, we demonstrated that Jak3 interacted with actin-binding protein villin, thereby facilitating cytoskeletal remodeling and wound repair. In this study, we characterize the structural determinants that regulate the interactions between Jak3 and cytoskeletal proteins of the villin/gelsolin family. Functional reconstitution of kinase activity by recombinant full-length (wt) Jak3 using Jak3-wt or villin/gelsolin-wt as substrate showed that Jak3 autophosphorylation was the rate-limiting step during interactions between Jak3 and cytoskeletal proteins. Determination of kinetic parameters showed that phosphorylated (P) Jak3-wt binds to P-villin-wt with a dissociation constant (K(d)) of 23 nM and a Hill's coefficient of 3.7. Pairwise binding between Jak3 mutants and P-villin-wt showed that the FERM domain of Jak3 was sufficient for binding to P-villin-wt with a K(d) of 40.0 nM. However, the SH2 domain of Jak3 prevented P-villin-wt from binding to the FERM domain of nonphosphorylated protein. We demonstrate that the intramolecular interaction between the FERM and SH2 domains of nonphosphorylated Jak3 prevented Jak3 from binding to villin and that tyrosine autophosphorylation of Jak3 at the SH2 domain decreased these intramolecular interactions and facilitated binding of the FERM domain to villin. Thus we demonstrate the molecular mechanism of interactions between Jak3 and cytoskeletal proteins where tyrosine phosphorylation of the SH2 domain acted as an intramolecular switch for the interactions between Jak3 and cytoskeletal proteins.
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Affiliation(s)
- Jayshree Mishra
- Department of Pharmaceutical Sciences, Irma Lerma Rangel (ILR) College of Pharmacy, Texas A&M Health Science Center, Kingsville, Texas 78363, USA
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Bao C, Wang J, Zhang R, Zhang B, Zhang H, Zhou Y, Huang S. Arabidopsis VILLIN2 and VILLIN3 act redundantly in sclerenchyma development via bundling of actin filaments. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 71:962-75. [PMID: 22563899 DOI: 10.1111/j.1365-313x.2012.05044.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The organization of the actin cytoskeleton has been implicated in sclerenchyma development. However, the molecular mechanisms linking the actin cytoskeleton to this process remain poorly understood. In particular, there have been no studies showing that direct genetic manipulation of the actin cytoskeleton affects sclerenchyma development. Villins belong to the villin/gelsolin/fragmin superfamily and are versatile actin-modifying proteins. Several recent studies have implicated villins in tip growth of single cells, but how villins act in multicellular plant development remains largely unknown. Here, we found that two closely related villin isovariants from Arabidopsis, VLN2 and VLN3, act redundantly in sclerenchyma development. Detailed analysis of cross-sections from inflorescence stems of vln2 vln3 double mutant plants revealed a reduction in stem size and in the number of vascular bundles; however, no defects in synthesis of the secondary cell wall were detected. Surprisingly, the vln2 vln3 double mutation did not affect cell elongation of inter-fascicular fibers. Biochemical analyses showed that recombinant VLN2 was able to cap, sever and bundle actin filaments, similar to VLN3. Consistent with these biochemical activities, loss of function of VLN2 and VLN3 resulted in a decrease in the amount of F-actin and actin bundles in plant cells. Collectively, our findings demonstrate that VLN2 and VLN3 act redundantly in sclerenchyma development via bundling of actin filaments.
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Affiliation(s)
- Chanchan Bao
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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Actin reorganization as the molecular basis for the regulation of apoptosis in gastrointestinal epithelial cells. Cell Death Differ 2012; 19:1514-24. [PMID: 22421965 DOI: 10.1038/cdd.2012.28] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The gastrointestinal (GI) epithelium is a rapidly renewing tissue in which apoptosis represents part of the overall homeostatic process. Regulation of apoptosis in the GI epithelium is complex with a precise relationship between cell position and apoptosis. Apoptosis occurs spontaneously and in response to radiation and cytotoxic drugs at the base of the crypts. By contrast, the villus epithelial cells are extremely resistant to apoptosis. The molecular mechanism underlying this loss of function of villus epithelial cells to undergo apoptosis shortly after their exit from the crypt is unknown. In this study we demonstrate for the first time, that deletion of two homologous actin-binding proteins, villin and gelsolin renders villus epithelial cells extremely sensitive to apoptosis. Ultrastructural analysis of the villin-gelsolin(-/-) double-knockout mice shows an abnormal accumulation of damaged mitochondria demonstrating that villin and gelsolin function on an early step in the apoptotic signaling at the level of the mitochondria. A characterization of functional and ligand-binding mutants demonstrate that regulated changes in actin dynamics determined by the actin severing activities of villin and gelsolin are required to maintain cellular homeostasis. Our study provides a molecular basis for the regulation of apoptosis in the GI epithelium and identifies cell biological mechanisms that couple changes in actin dynamics to apoptotic cell death.
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Arango D, Al-Obaidi S, Williams DS, Dopeso H, Mazzolini R, Corner G, Byun DS, Carr AA, Murone C, Tögel L, Zeps N, Aaltonen LA, Iacopetta B, Mariadason JM. Villin expression is frequently lost in poorly differentiated colon cancer. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:1509-21. [PMID: 22349300 DOI: 10.1016/j.ajpath.2012.01.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 12/13/2011] [Accepted: 01/03/2012] [Indexed: 12/14/2022]
Abstract
Colorectal cancers (CRCs) are classified as having microsatellite instability (MSI) or chromosomal instability (CIN); herein termed microsatellite stable (MSS). MSI colon cancers frequently display a poorly differentiated histology for which the molecular basis is not well understood. Gene expression and immunohistochemical profiling of MSS and MSI CRC cell lines and tumors revealed significant down-regulation of the intestinal-specific cytoskeletal protein villin in MSI colon cancer, with complete absence in 62% and 17% of MSI cell lines and tumors, respectively. Investigation of 577 CRCs linked loss of villin expression to poorly differentiated histology in MSI and MSS tumors. Furthermore, mislocalization of villin from the membrane was prognostic for poorer outcome in MSS patients. Loss of villin expression was not due to coding sequence mutations, epigenetic inactivation, or promoter mutation. Conversely, in transient transfection assays villin promoter activity reflected endogenous villin expression, suggesting transcriptional control. A screen of gut-specific transcription factors revealed a significant correlation between expression of villin and the homeobox transcription factor Cdx-1. Cdx-1 overexpression induced villin promoter activity, Cdx-1 knockdown down-regulated endogenous villin expression, and deletion of a key Cdx-binding site within the villin promoter attenuated promoter activity. Loss of Cdx-1 expression in CRC lines was associated with Cdx-1 promoter methylation. These findings demonstrate that loss of villin expression due to Cdx-1 loss is a feature of poorly differentiated CRCs.
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Affiliation(s)
- Diego Arango
- Molecular Biology and Biochemistry Research Center-Nanomedicine, Vall d'Hebron University Hospital Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
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Sumigray KD, Lechler T. Desmoplakin controls microvilli length but not cell adhesion or keratin organization in the intestinal epithelium. Mol Biol Cell 2012; 23:792-9. [PMID: 22238362 PMCID: PMC3290639 DOI: 10.1091/mbc.e11-11-0923] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Desmosomes are cell–cell adhesion structures whose canonical functions are control of intermediate filament organization and tissue strength. In the intestinal epithelium, desmosomes do not mediate these functions but instead control the brush border architecture of the enterocytes. Maintaining proper cell–cell adhesion in the intestine is essential for tissue homeostasis and barrier function. This adhesion is thought to be mediated by cell adhesion structures, including tight junctions, adherens junctions, and desmosomes, which concentrate in the apical junctional region. While clear roles for adherens and tight junctions have been established in simple epithelia, the function of desmosomes has not been addressed. In stratified epithelia, desmosomes impart mechanical strength to tissues by organizing and anchoring the keratin filament network. In this paper, we report that the desmosomal protein desmoplakin (DP) is not essential for cell adhesion in the intestinal epithelium. Surprisingly, when DP is lacking, keratin filament localization is also unperturbed, although keratin filaments no longer anchor at desmosomes. Unexpectedly, DP is important for proper microvillus structure. Our study highlights the tissue-specific functions of desmosomes and reveals that the canonical functions for these structures are not conserved in simple epithelium.
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Affiliation(s)
- Kaelyn D Sumigray
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
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