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Bonnet H, Isidro Alonso CA, Gupta IR. Submandibular gland epithelial development and the importance of junctions. Tissue Barriers 2023; 11:2161255. [PMID: 36576256 PMCID: PMC10606785 DOI: 10.1080/21688370.2022.2161255] [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: 07/03/2022] [Revised: 12/08/2022] [Accepted: 12/18/2022] [Indexed: 12/29/2022] Open
Abstract
Salivary glands consist of highly specialized epithelial cells that secrete the fluid, saliva, and/or transport saliva into the oral cavity. Saliva is essential to lubricate the oral cavity for food consumption and to maintain the hygiene of the oral cavity. In this review, we will focus on the formation of the epithelial cell lineage and the cell junctions that are essential for formation of saliva and maintenance of the epithelial barrier between the ducts that transport saliva and the extracellular environment.
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Affiliation(s)
| | - Carlos Agustin Isidro Alonso
- Research Institute of the McGill University Health Center, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Indra R. Gupta
- Research Institute of the McGill University Health Center, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
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2
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Wong WY, Pier M, Limesand KH. Persistent disruption of lateral junctional complexes and actin cytoskeleton in parotid salivary glands following radiation treatment. Am J Physiol Regul Integr Comp Physiol 2018; 315:R656-R667. [PMID: 29897817 PMCID: PMC6230885 DOI: 10.1152/ajpregu.00388.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 06/11/2018] [Accepted: 06/12/2018] [Indexed: 02/02/2023]
Abstract
Xerostomia and hyposalivation are debilitating side effects for patients treated with ionizing radiation for head and neck cancer. Despite technological advances, collateral damage to the salivary glands remains a significant problem for patients and severely diminishes their quality of life. During the wound healing process, restoration of junctional contacts is necessary to maintain polarity, structural integrity, and orientation cues for secretion. However, little is known about whether these structural molecules are impacted following radiation damage and more importantly, during tissue restoration. We evaluated changes in adherens junctions and cytoskeletal regulators in an injury model where mice were irradiated with 5 Gy and a restoration model where mice injected postradiation with insulin-like growth factor 1 (IGF1) are capable of restoring salivary function. Using coimmunoprecipitation, there is a decrease in epithelial (E)-cadherin bound to β-catenin following damage that is restored to untreated levels with IGF1. Via its adaptor proteins, β-catenin links the cadherins to the cytoskeleton and part of this regulation is mediated through Rho-associated coiled-coil containing kinase (ROCK) signaling. In our radiation model, filamentous (F)-actin organization is fragmented, and there is an induction of ROCK activity. However, a ROCK inhibitor, Y-27632, prevents E-cadherin/β-catenin dissociation following radiation treatment. These findings illustrate that radiation induces a ROCK-dependent disruption of the cadherin-catenin complex and alters F-actin organization at stages of damage when hyposalivation is observed. Understanding the regulation of these components will be critical in the discovery of therapeutics that have the potential to restore function in polarized epithelium.
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Affiliation(s)
- Wen Yu Wong
- Cancer Biology Graduate Interdisciplinary Program, University of Arizona , Tucson, Arizona
| | - Maricela Pier
- Department of Nutritional Sciences, University of Arizona , Tucson, Arizona
| | - Kirsten H Limesand
- Cancer Biology Graduate Interdisciplinary Program, University of Arizona , Tucson, Arizona
- Department of Nutritional Sciences, University of Arizona , Tucson, Arizona
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3
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Logan CM, Bowen CJ, Menko AS. Induction of Immune Surveillance of the Dysmorphogenic Lens. Sci Rep 2017; 7:16235. [PMID: 29176738 PMCID: PMC5701161 DOI: 10.1038/s41598-017-16456-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/12/2017] [Indexed: 01/10/2023] Open
Abstract
The lens has been considered to be an immune privileged site not susceptible to the immune processes normally associated with tissue injury and wound repair. However, as greater insight into the immune surveillance process is gained, we have reevaluated the concept of immune privilege. Our studies using an N-cadherin lens-specific conditional knockout mouse, N-cadΔlens, show that loss of this cell-cell junctional protein leads to lens degeneration, necrosis and fibrotic change, postnatally. The degeneration of this tissue induces an immune response resulting in immune cells populating the lens that contribute to the development of fibrosis. Additionally, we demonstrate that the lens is connected to the lymphatic system, with LYVE(+) labeling reaching the lens along the suspensory ligaments that connect the lens to the ciliary body, providing a potential mechanism for the immune circulation. Importantly, we observe that degeneration of the lens activates an immune response throughout the eye, including cornea, vitreous humor, and retina, suggesting a coordinated protective response in the visual system to defects of a component tissue. These studies demonstrate that lens degeneration induces an immune response that can contribute to the fibrosis that often accompanies lens dysgenesis, a consideration for understanding organ system response to injury.
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Affiliation(s)
- Caitlin M Logan
- Thomas Jefferson University, Department of Pathology, Anatomy and Cell Biology, Philadelphia, Pennsylvania, 19107, United States
| | - Caitlin J Bowen
- Thomas Jefferson University, Department of Pathology, Anatomy and Cell Biology, Philadelphia, Pennsylvania, 19107, United States
| | - A Sue Menko
- Thomas Jefferson University, Department of Pathology, Anatomy and Cell Biology, Philadelphia, Pennsylvania, 19107, United States.
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4
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Daley WP, Matsumoto K, Doyle AD, Wang S, DuChez BJ, Holmbeck K, Yamada KM. RETRACTED: Btbd7 is essential for region-specific epithelial cell dynamics and branching morphogenesis in vivo. Development 2017; 144:2200-2211. [PMID: 28506999 PMCID: PMC5482991 DOI: 10.1242/dev.146894] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 05/10/2017] [Indexed: 12/18/2022]
Abstract
Branching morphogenesis of developing organs requires coordinated but poorly understood changes in epithelial cell-cell adhesion and cell motility. We report that Btbd7 is a crucial regulator of branching morphogenesis in vivo. Btbd7 levels are elevated in peripheral cells of branching epithelial end buds, where it enhances cell motility and cell-cell adhesion dynamics. Genetic ablation of Btbd7 in mice disrupts branching morphogenesis of salivary gland, lung and kidney. Btbd7 knockout results in more tightly packed outer bud cells, which display stronger E-cadherin localization, reduced cell motility and decreased dynamics of transient cell separations associated with cleft formation; inner bud cells remain unaffected. Mechanistic analyses using in vitro MDCK cells to mimic outer bud cell behavior establish that Btbd7 promotes loss of E-cadherin from cell-cell adhesions with enhanced migration and transient cell separation. Btbd7 can enhance E-cadherin ubiquitination, internalization, and degradation in MDCK and peripheral bud cells for regulating cell dynamics. These studies show how a specific regulatory molecule, Btbd7, can function at a local region of developing organs to regulate dynamics of cell adhesion and motility during epithelial branching morphogenesis.
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Affiliation(s)
- William P Daley
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kazue Matsumoto
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrew D Doyle
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shaohe Wang
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Brian J DuChez
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kenn Holmbeck
- Skeletal Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kenneth M Yamada
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
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5
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Shubin AD, Felong TJ, Graunke D, Ovitt CE, Benoit DS. Development of poly(ethylene glycol) hydrogels for salivary gland tissue engineering applications. Tissue Eng Part A 2015; 21:1733-51. [PMID: 25762214 PMCID: PMC4449707 DOI: 10.1089/ten.tea.2014.0674] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 02/09/2015] [Indexed: 12/21/2022] Open
Abstract
More than 40,000 patients are diagnosed with head and neck cancers annually in the United States with the vast majority receiving radiation therapy. Salivary glands are irreparably damaged by radiation therapy resulting in xerostomia, which severely affects patient quality of life. Cell-based therapies have shown some promise in mouse models of radiation-induced xerostomia, but they suffer from insufficient and inconsistent gland regeneration and accompanying secretory function. To aid in the development of regenerative therapies, poly(ethylene glycol) hydrogels were investigated for the encapsulation of primary submandibular gland (SMG) cells for tissue engineering applications. Different methods of hydrogel formation and cell preparation were examined to identify cytocompatible encapsulation conditions for SMG cells. Cell viability was much higher after thiol-ene polymerizations compared with conventional methacrylate polymerizations due to reduced membrane peroxidation and intracellular reactive oxygen species formation. In addition, the formation of multicellular microspheres before encapsulation maximized cell-cell contacts and increased viability of SMG cells over 14-day culture periods. Thiol-ene hydrogel-encapsulated microspheres also promoted SMG proliferation. Lineage tracing was employed to determine the cellular composition of hydrogel-encapsulated microspheres using markers for acinar (Mist1) and duct (Keratin5) cells. Our findings indicate that both acinar and duct cell phenotypes are present throughout the 14 day culture period. However, the acinar:duct cell ratios are reduced over time, likely due to duct cell proliferation. Altogether, permissive encapsulation methods for primary SMG cells have been identified that promote cell viability, proliferation, and maintenance of differentiated salivary gland cell phenotypes, which allows for translation of this approach for salivary gland tissue engineering applications.
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Affiliation(s)
- Andrew D. Shubin
- Department of Biomedical Engineering, University of Rochester, Rochester, New York
| | - Timothy J. Felong
- Department of Biomedical Engineering, University of Rochester, Rochester, New York
| | - Dean Graunke
- Department of Biomedical Engineering, University of Rochester, Rochester, New York
| | - Catherine E. Ovitt
- Center for Oral Biology, University of Rochester, Rochester, New York
- Department of Biomedical Genetics, University of Rochester, Rochester, New York
| | - Danielle S.W. Benoit
- Department of Biomedical Engineering, University of Rochester, Rochester, New York
- Center for Oral Biology, University of Rochester, Rochester, New York
- Department of Chemical Engineering, University of Rochester, Rochester, New York
- Center for Musculoskeletal Research, Rochester, New York
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Patel VN, Hoffman MP. Salivary gland development: a template for regeneration. Semin Cell Dev Biol 2013; 25-26:52-60. [PMID: 24333774 DOI: 10.1016/j.semcdb.2013.12.001] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 11/26/2013] [Accepted: 12/02/2013] [Indexed: 12/16/2022]
Abstract
The mammalian salivary gland develops as a highly branched structure designed to produce and secrete saliva. This review will focus on research on mouse submandibular gland development and the translation of this basic research toward therapy for patients suffering from salivary hypofunction. Here we review the most recent literature that has enabled a better understanding of the mechanisms of salivary gland development. Additionally, we discuss approaches proposed to restore salivary function using gene and cell-based therapy. Increasing our understanding of the developmental mechanisms involved during development is critical to design effective therapies for regeneration and repair of damaged glands.
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Affiliation(s)
- Vaishali N Patel
- Matrix and Morphogenesis Section, Laboratory of Cell and Developmental Biology, NIDCR, NIH, Bethesda, MD 20892, United States
| | - Matthew P Hoffman
- Matrix and Morphogenesis Section, Laboratory of Cell and Developmental Biology, NIDCR, NIH, Bethesda, MD 20892, United States.
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The Hippo signaling pathway is required for salivary gland development and its dysregulation is associated with Sjogren's syndrome. J Transl Med 2013; 93:1203-18. [PMID: 24080911 PMCID: PMC3864807 DOI: 10.1038/labinvest.2013.114] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 08/30/2013] [Accepted: 08/30/2013] [Indexed: 12/21/2022] Open
Abstract
Sjogren's syndrome (SS) is a complex autoimmune disease that primarily affects salivary and lacrimal glands and is associated with high morbidity. Although the prevailing dogma is that immune system pathology drives SS, increasing evidence points to structural defects, including defective E-cadherin adhesion, to be involved in its etiology. We have shown that E-cadherin has pivotal roles in the development of the mouse salivary submandibular gland (SMG) by organizing apical-basal polarity in acinar and ductal progenitors and by signaling survival for differentiating duct cells. Recently, E-cadherin junctions have been shown to interact with effectors of the Hippo signaling pathway, a core pathway regulating the organ size, cell proliferation, and differentiation. We now show that Hippo signaling is required for SMG-branching morphogenesis and is involved in the pathophysiology of SS. During SMG development, a Hippo pathway effector, TAZ, becomes increasingly phosphorylated and associated with E-cadherin and α-catenin, consistent with the activation of Hippo signaling. Inhibition of Lats2, an upstream kinase that promotes TAZ phosphorylation, results in dysmorphogenesis of the SMG and impaired duct formation. SMGs from non-obese diabetic mice, a mouse model for SS, phenocopy the Lats2-inhibited SMGs and exhibit a reduction in E-cadherin junctional components, including TAZ. Importantly, labial specimens from human SS patients display mislocalization of TAZ from junctional regions to the nucleus, coincident with accumulation of extracellular matrix components, fibronectin and connective tissue growth factor, known downstream targets of TAZ. Our studies show that Hippo signaling has a crucial role in SMG-branching morphogenesis and provide evidence that defects in this pathway are associated with SS in humans.
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Daley WP, Yamada KM. Cell–ECM Interactions and the Regulation of Epithelial Branching Morphogenesis. EXTRACELLULAR MATRIX IN DEVELOPMENT 2013. [DOI: 10.1007/978-3-642-35935-4_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Kehagias N, Epivatianos A, Sakas L, Andreadis D, Markopoulos A, Antoniades K. Expression of N-cadherin in salivary gland tumors. Med Princ Pract 2013; 22:59-64. [PMID: 22738870 PMCID: PMC5586701 DOI: 10.1159/000339213] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/29/2012] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE To detect immunohistochemically the N-cadherin expression in different types of benign and malignant salivary gland tumors in an attempt to note any possible correlation to their development, stage and invasive properties. MATERIALS AND METHODS N-cadherin expression was examined in tissue specimens from 49 salivary gland tumors including: pleomorphic adenomas (4), Warthin's tumors (10), and myoepitheliomas (4) (benign tumors), as well as adenoid cystic carcinomas (14), mucoepidermoid carcinomas (4), polymorphous low-grade adenocarcinomas (6), and adenocarcinomas not otherwise specified (5) (malignant tumors). Twelve specimens of normal salivary glands were used as control. The perineural invasion and stage of malignant salivary gland tumors were evaluated. Immunohistochemical procedure was performed automatically using the Bond Polymer Refine Detection Kit. RESULTS N-cadherin expression was not found in normal salivary glands. In benign salivary gland tumors, N-cadherin along membranes of neoplastic cells as well as in centrocytes of lymphoid germinal centers was seen in 1 and 4 cases of Warthin's tumors, respectively. Varied degree of N-cadherin expression was found in 13 (45%) cases of malignant salivary gland tumors. N-cadherin expression was significantly correlated with perineural invasion (χ(2) = 11.7, p < 0.0001), but not with stage of malignant salivary gland tumors. CONCLUSION N-cadherin expression was observed in malignant salivary gland tumors and could be an indicator of potentially aggressive behavior. N-cadherin expression by tumor cells could be attributed to perineural invasion.
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Affiliation(s)
- N. Kehagias
- Department of Oral and Maxillofacial Surgery, Thessaloniki, Greece
| | - A. Epivatianos
- Department of Oral Medicine and Oral Pathology, Dental School of Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - L. Sakas
- Department of Department of Histopathology, ‘G. Papanikolaou’ General Hospital of Thessaloniki, Thessaloniki, Greece
| | - D. Andreadis
- Department of Oral Medicine and Oral Pathology, Dental School of Aristotle University of Thessaloniki, Thessaloniki, Greece
- *D. Andreadis, DDS, PhD, Department of Oral Medicine/Pathology, School of Dentistry, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece), Tel. +30 231 099 9538, E-Mail
| | - A. Markopoulos
- Department of Oral Medicine and Oral Pathology, Dental School of Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - K. Antoniades
- Department of Oral and Maxillofacial Surgery, Thessaloniki, Greece
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Shiratsuchi H, Shimizu O, Saito T, Mashimo T, Yonehara Y. Immunohistological study of small Rho GTPases and β-catenin during regeneration of the rat submandibular gland. J Mol Histol 2012; 43:751-9. [DOI: 10.1007/s10735-012-9437-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 07/09/2012] [Indexed: 01/12/2023]
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Daley WP, Gervais EM, Centanni SW, Gulfo KM, Nelson DA, Larsen M. ROCK1-directed basement membrane positioning coordinates epithelial tissue polarity. Development 2012; 139:411-22. [PMID: 22186730 PMCID: PMC3243099 DOI: 10.1242/dev.075366] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2011] [Indexed: 12/23/2022]
Abstract
The basement membrane is crucial for epithelial tissue organization and function. However, the mechanisms by which basement membrane is restricted to the basal periphery of epithelial tissues and the basement membrane-mediated signals that regulate coordinated tissue organization are not well defined. Here, we report that Rho kinase (ROCK) controls coordinated tissue organization by restricting basement membrane to the epithelial basal periphery in developing mouse submandibular salivary glands, and that ROCK inhibition results in accumulation of ectopic basement membrane throughout the epithelial compartment. ROCK-regulated restriction of PAR-1b (MARK2) localization in the outer basal epithelial cell layer is required for basement membrane positioning at the tissue periphery. PAR-1b is specifically required for basement membrane deposition, as inhibition of PAR-1b kinase activity prevents basement membrane deposition and disrupts overall tissue organization, and suppression of PAR-1b together with ROCK inhibition prevents interior accumulations of basement membrane. Conversely, ectopic overexpression of wild-type PAR-1b results in ectopic interior basement membrane deposition. Significantly, culture of salivary epithelial cells on exogenous basement membrane rescues epithelial organization in the presence of ROCK1 or PAR-1b inhibition, and this basement membrane-mediated rescue requires functional integrin β1 to maintain epithelial cell-cell adhesions. Taken together, these studies indicate that ROCK1/PAR-1b-dependent regulation of basement membrane placement is required for the coordination of tissue polarity and the elaboration of tissue structure in the developing submandibular salivary gland.
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Affiliation(s)
- William P. Daley
- Graduate program in Molecular, Cellular, Developmental, and Neural Biology, University at Albany, State University of New York, Albany, NY 12208, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12208, USA
| | - Elise M. Gervais
- Graduate program in Molecular, Cellular, Developmental, and Neural Biology, University at Albany, State University of New York, Albany, NY 12208, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12208, USA
| | - Samuel W. Centanni
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12208, USA
| | - Kathryn M. Gulfo
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12208, USA
| | - Deirdre A. Nelson
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12208, USA
| | - Melinda Larsen
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12208, USA
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The impact of compositional topography of amniotic membrane scaffold on tissue morphogenesis of salivary gland. Biomaterials 2011; 32:4424-32. [PMID: 21439637 DOI: 10.1016/j.biomaterials.2011.02.057] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 02/27/2011] [Indexed: 12/16/2022]
Abstract
Amniotic membrane (AM) has been widely used in the reconstruction of oral epithelial defects. However, whether it is also effective in facilitating tissue formation of salivary gland, an appendix of oral epithelia, has never been explored. To investigate the effects and the underlying mechanism of AM on salivary gland morphogenesis, murine fetal submandibular gland (SMG) explants were cultured on different preparations of AM scaffolds. It was found that, on AM stromal scaffold, SMG demonstrated well-developed branching morphogenesis. Nonetheless, on AM epithelial scaffold, SMG epithelial cell converted to a spindle-shape, lost intercellular connection, changed cytoskeletal organization, and exhibited scattering behaviors. Meanwhile, the integrity of SMG basement membrane was dismantled as well. However, when acellular AM epithelial scaffold was used, cultured SMG demonstrated organized morphology, indicating that AM epithelial component provided specific surface features for SMG morphogenesis. To further investigate AM scaffold morphogenetic effect, it was found hepatocyte growth factor (HGF), an epithelial scattering factor, was expressed abundantly in cultivated AM epithelia. After blocking HGF function of AM, cultured SMG regained branching activity, reorganized cell adhesion and subcellular organization, and reproduced basement membranes. Therefore, AM-derived bioactive factor profoundly influences cell behaviors and structure formation of SMG. Together, this study showed that compositional topography of AM scaffold is important in affecting SMG morphogenesis. By understanding the effects of AM scaffold on SMG morphogenesis, it provides important information for rationally designing and fabricating AM scaffold for salivary gland regeneration.
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Tessmer MS, Reilly EC, Brossay L. Salivary gland NK cells are phenotypically and functionally unique. PLoS Pathog 2011; 7:e1001254. [PMID: 21249177 PMCID: PMC3020929 DOI: 10.1371/journal.ppat.1001254] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Accepted: 12/10/2010] [Indexed: 12/31/2022] Open
Abstract
Natural killer (NK) cells and CD8+ T cells play vital roles in containing and eliminating systemic cytomegalovirus (CMV). However, CMV has a tropism for the salivary gland acinar epithelial cells and persists in this organ for several weeks after primary infection. Here we characterize a distinct NK cell population that resides in the salivary gland, uncommon to any described to date, expressing both mature and immature NK cell markers. Using RORγt reporter mice and nude mice, we also show that the salivary gland NK cells are not lymphoid tissue inducer NK-like cells and are not thymic derived. During the course of murine cytomegalovirus (MCMV) infection, we found that salivary gland NK cells detect the infection and acquire activation markers, but have limited capacity to produce IFN-γ and degranulate. Salivary gland NK cell effector functions are not regulated by iNKT or Treg cells, which are mostly absent in the salivary gland. Additionally, we demonstrate that peripheral NK cells are not recruited to this organ even after the systemic infection has been controlled. Altogether, these results indicate that viral persistence and latency in the salivary glands may be due in part to the presence of unfit NK cells and the lack of recruitment of peripheral NK cells. Human cytomegalovirus (HCMV) is a herpesvirus that infects 50–95% of human populations. In immunocompetent individuals, a primary infection often goes unnoticed and when resolved by the adaptive immune response, HCMV enters into a latent phase. The natural mouse pathogen murine CMV (MCMV) is a well-characterized animal model of viral infection that results in a non-replicative, chronic infection of an immunocompetent animal. MCMV is cleared efficiently by cytotoxic lymphocytes in all organs of the infected host, except the submandibular gland (SMG) of the salivary glands where it persists for several months eventually becoming latent for the life of the host. The acute response to this virus is dependent in part on natural killer (NK) cell cytotoxicity, as animals deficient in NK cells rapidly succumb to infection. Here, we identify a distinct salivary gland resident NK cell population, which detects the infection but remains mostly hyporesponsive. Peripheral NK cells, which control infection in the spleen, are not recruited to the salivary gland. Altogether, these data imply that CMV latency in the SMG could result from inadequate NK cell responses and can potentially lead to immune intervention to reverse CMV latency.
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Affiliation(s)
- Marlowe S. Tessmer
- Department of Molecular Microbiology and Immunology and Graduate Program in Pathobiology, Division of Biology and Medicine, Brown University, Providence, Rhode Island, United States of America
| | - Emma C. Reilly
- Department of Molecular Microbiology and Immunology and Graduate Program in Pathobiology, Division of Biology and Medicine, Brown University, Providence, Rhode Island, United States of America
| | - Laurent Brossay
- Department of Molecular Microbiology and Immunology and Graduate Program in Pathobiology, Division of Biology and Medicine, Brown University, Providence, Rhode Island, United States of America
- * E-mail:
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14
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Tight junctions in salivary epithelium. J Biomed Biotechnol 2010; 2010:278948. [PMID: 20182541 PMCID: PMC2825559 DOI: 10.1155/2010/278948] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 11/12/2009] [Accepted: 11/27/2009] [Indexed: 12/13/2022] Open
Abstract
Epithelial cell tight junctions (TJs) consist of a narrow belt-like structure in the apical region of the lateral plasma membrane that circumferentially binds each cell to its neighbor. TJs are found in tissues that are involved in polarized secretions, absorption functions, and maintaining barriers between blood and interstitial fluids. The morphology, permeability, and ion selectivity of TJ vary among different types of tissues and species. TJs are very dynamic structures that assemble, grow, reorganize, and disassemble during physiological or pathological events. Several studies have indicated the active role of TJ in intestinal, renal, and airway epithelial function; however, the functional significance of TJ in salivary gland epithelium is poorly understood. Interactions between different combinations of the TJ family (each with their own unique regulatory proteins) define tissue specificity and functions during physiopathological processes; however, these interaction patterns have not been studied in salivary glands. The purpose of this review is to analyze some of the current data regarding the regulatory components of the TJ that could potentially affect cellular functions of the salivary epithelium.
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15
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Naka T, Yokose S. Immunohistochemical localization of barx2 in the developing fetal mouse submandibular glands. Acta Histochem Cytochem 2009; 42:47-53. [PMID: 19492027 PMCID: PMC2685023 DOI: 10.1267/ahc.08027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Accepted: 01/28/2009] [Indexed: 12/29/2022] Open
Abstract
The development of mouse submandibular gland (SMG) begins at embryonic day 11.5-12 (E11.5-12), during which successive rounds of epithelial clefting and branching create complex epithelial tree-like structures. Homeobox genes regulate place-dependent morphogenesis, including epithelial-mesenchymal interactions, and control the expression patterns of signaling molecules. The Barx2 containing Homeobox exerts several key roles in development. Some studies have shown that the Barx2 plays important roles in the epithelial-mesenchymal interactions of organogenesis. However, the mechanisms of Barx2 associated with the development of SMG are obscure. In this study, we demonstrated for the first time the exact spatial and temporal Barx2 expression pattern in SMG epithelial tissue during development using immunohistochemical staining and Real-Time quantitative PCR. Barx2 was expressed in the nucleus of the epithelial cells located in the proliferative and differentiative regions of the developing SMG during the early development stages (E11.5-E13.5). After the E14.5-time period, the expression gradually decreased, and at E16.5, expression mostly disappeared despite the fact that evidence of cytodifferentiation, such as the appearance of proacinar cells, distinct lumen formation, and secretory products, was beginning to be observed. Results of Real-Time PCR demonstrated that the amount of Barx2 mRNA expression in SMG was maximal on E14.5, and gradually decreased by E18.5. These results indicate that Barx2 is associated with early stage epithelial tissue development, and can be a useful epithelial marker of the SMG during early developmental stages.
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Affiliation(s)
- Takahiro Naka
- Division of Restorative Dentistry, Department of Conservative Dentistry, Ohu University School of Dentistry, 31–1, Misumido, Koriyama, Fukushima 963–8611, Japan
| | - Satoshi Yokose
- Division of Restorative Dentistry, Department of Conservative Dentistry, Ohu University School of Dentistry, 31–1, Misumido, Koriyama, Fukushima 963–8611, Japan
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16
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Walker JL, Menko AS, Khalil S, Rebustini I, Hoffman MP, Kreidberg JA, Kukuruzinska MA. Diverse roles of E-cadherin in the morphogenesis of the submandibular gland: insights into the formation of acinar and ductal structures. Dev Dyn 2009; 237:3128-41. [PMID: 18816447 DOI: 10.1002/dvdy.21717] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The formation of acinar and ductal structures during epithelial tissue branching morphogenesis is not well understood. We report that in the mouse submandibular gland (SMG), acinar and ductal cell fates are determined early in embryonic morphogenesis with E-cadherin playing pivotal roles in development. We identified two morphologically distinct cell populations at the single bud stage, destined for different functions. The outer layer of columnar cells with organized E-cadherin junctions expressed the neonatal acinar marker B1 by E13.5, demonstrating their acinar fate. The interior cells initially lacked distinct E-cadherin junctions, but with morphogenesis formed cytokeratin 7 (K7) -positive ductal structures with organized E-cadherin junctions and F-actin filaments. Inhibition of E-cadherin function with either siRNA or function blocking antibody caused extensive apoptosis of ductal cells and aberrantly dilated lumens, providing the first evidence that E-cadherin regulates ductal lumen formation during branching morphogenesis of the salivary gland.
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Affiliation(s)
- Janice L Walker
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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17
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Distribution of small Rho GTPases in the developing rat submandibular gland. J Mol Histol 2008; 39:519-25. [PMID: 18784978 DOI: 10.1007/s10735-008-9192-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Accepted: 08/12/2008] [Indexed: 12/22/2022]
Abstract
During the rat submandibular gland (SMG) development, organogenesis and cytodifferentiation depend on the actin cytoskeleton, which is regulated by small Rho GTPases. These proteins link cell surface receptors to pathways that regulate cell motility, polarity, gene expression, vesicular trafficking, proliferation and apoptosis. The aim of this study was to evaluate, by immunohistochemistry, the distribution pattern of RhoA, RhoB, RhoC, Rac1 and Cdc42 during cytodifferentiation of the rat SMG and in male adults. All GTPases were found in epithelial and mesenchymal tissues throughout gland development. Rac1 appeared to be important for parenchyma expansion at the beginning of cytodifferentiation, while RhoC, Cdc42 and the inactive phosphorylated form of Rac1 seemed associated with lumen formation and cell polarization in terminal tubules. RhoA and RhoB labeling was evident throughout development. All GTPases were differentially expressed in the adult gland, suggesting that they play specific roles during differentiation and function of the rat SMG.
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18
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Xi JH, Bai F, Gross J, Townsend RR, Menko AS, Andley UP. Mechanism of small heat shock protein function in vivo: a knock-in mouse model demonstrates that the R49C mutation in alpha A-crystallin enhances protein insolubility and cell death. J Biol Chem 2007; 283:5801-14. [PMID: 18056999 DOI: 10.1074/jbc.m708704200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
alphaA-crystallin (Cryaa/HSPB4) is a small heat shock protein and molecular chaperone that prevents nonspecific aggregation of denaturing proteins. Several point mutations in the alphaA-crystallin gene cause congenital human cataracts by unknown mechanisms. We took a novel approach to investigate the molecular mechanism of cataract formation in vivo by creating gene knock-in mice expressing the arginine 49 to cysteine mutation (R49C) in alphaA-crystallin (alphaA-R49C). This mutation has been linked with autosomal dominant hereditary cataracts in a four-generation Caucasian family. Homologous recombination in embryonic stem cells was performed using a plasmid containing the C to T transition in exon 1 of the cryaa gene. alphaA-R49C heterozygosity led to early cataracts characterized by nuclear opacities. Unexpectedly, alphaA-R49C homozygosity led to small eye phenotype and severe cataracts at birth. Wild type littermates did not show these abnormalities. Lens fiber cells of alphaA-R49C homozygous mice displayed an increase in cell death by apoptosis mediated by a 5-fold decrease in phosphorylated Bad, an anti-apoptotic protein, but an increase in Bcl-2 expression. However, proliferation measured by in vivo bromodeoxyuridine labeling did not decline. The alphaA-R49C heterozygous and homozygous knock-in lenses demonstrated an increase in insoluble alphaA-crystallin and alphaB-crystallin and a surprising increase in expression of cytoplasmic gamma-crystallin, whereas no changes in beta-crystallin were observed. Co-immunoprecipitation analysis showed increased interaction between alphaA-crystallin and lens substrate proteins in the heterozygous knock-in lenses. To our knowledge this is the first knock-in mouse model for a crystallin mutation causing hereditary human cataract and establishes that alphaA-R49C promotes protein insolubility and cell death in vivo.
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Affiliation(s)
- Jing-hua Xi
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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19
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Abstract
Salivary gland branching morphogenesis involves coordinated cell growth, proliferation, differentiation, migration, apoptosis, and interaction of epithelial, mesenchymal, endothelial, and neuronal cells. The ex vivo analysis of embryonic mouse submandibular glands, which branch so reproducibly and beautifully in culture, is a powerful tool to investigate the molecular mechanisms regulating epithelium-mesenchyme interactions during development. The more recent analysis of genetically modified mice provides insight into the genetic regulation of branching morphogenesis. The review begins, as did the field historically, focusing on the role of the extracellular matrix (ECM), and its components such as glycosaminoglycans, collagens, and laminins. Following sections describe the modification of the ECM by proteases and the role of cell-matrix and cell-cell receptors. The review then focuses on two major families of growth factors implicated in salivary gland development, the fibroblast growth factors (FGFs) and the epidermal growth factors (EGFs). The salivary gland phenotypes in mice with genetic modification of FGFs and their receptors highlight the central role of FGFs during salivary gland branching morphogenesis. A broader section mentions other molecules implicated from analysis of the phenotypes of genetically modified mice or organ culture experiments. The review concludes with speculation on some future areas of research.
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Affiliation(s)
- Vaishali N Patel
- Matrix and Morphogenesis Unit, Craniofacial Developmental Biology and Regeneration Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, 30 Convent Dr Bethesda, MD 20892, USA
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20
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Liwosz A, Lei T, Kukuruzinska MA. N-glycosylation affects the molecular organization and stability of E-cadherin junctions. J Biol Chem 2006; 281:23138-49. [PMID: 16682414 DOI: 10.1074/jbc.m512621200] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Epithelial cell-cell adhesion is mediated by E-cadherin, an intercellular N-glycoprotein adhesion receptor that functions in the assembly of multiprotein complexes anchored to the actin cytoskeleton named adherens junctions (AJs). E-cadherin ectodomains 4 and 5 contain three potential N-glycan addition sites, although their significance in AJ stability is unclear. Here we show that sparse cells lacking stable AJs produced E-cadherin that was extensively modified with complex N-glycans. In contrast, dense cultures with more stable AJs had scarcely N-glycosylated E-cadherin modified with high mannose/hybrid and limited complex N-glycans. This suggested that variations in AJ stability were accompanied by quantitative and qualitative changes in E-cadherin N-glycosylation. To further examine the role of N-glycans in AJ function, we generated E-cadherin N-glycosylation variants lacking selected N-glycan addition sites. Characterization of these variants in CHO cells, lacking endogenous E-cadherin, revealed that site 1 on ectodomain 4 was modified with a prominent complex N-glycan, site 2 on ectodomain 5 did not have a substantial oligosaccharide, and site 3 on ectodomain 5 was decorated with a high mannose/hybrid N-glycan. Removal of complex N-glycan from ectodomain 4 led to a dramatically increased interaction of E-cadherin-catenin complexes with vinculin and the actin cytoskeleton. The latter effect was further enhanced by the deletion of the high mannose/hybrid N-glycan from site 3. In MDCK cells, which produce E-cadherin, a variant lacking both complex and high mannose/hybrid N-glycans functioned like a dominant positive displaying increased interaction with gamma-catenin and vinculin compared with the endogenous E-cadherin. Collectively, our studies show that N-glycans, and complex oligosaccharides in particular, destabilize AJs by affecting their molecular organization.
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Affiliation(s)
- Aneta Liwosz
- Department of Molecular and Cell Biology, School of Dental Medicine, Boston University, Boston, Massachusetts 02118, USA
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21
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Larsen M, Wei C, Yamada KM. Cell and fibronectin dynamics during branching morphogenesis. J Cell Sci 2006; 119:3376-84. [PMID: 16882689 DOI: 10.1242/jcs.03079] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Branching morphogenesis is a dynamic developmental process shared by many organs, but the mechanisms that reorganize cells during branching morphogenesis are not well understood. We hypothesized that extensive cell rearrangements are involved, and investigated cell migration using two-color confocal time-lapse microscopy to image cell and extracellular-matrix dynamics in developing salivary glands. We labeled submandibular salivary gland (SMG) epithelial cells with green fluorescent protein and matrix with fluorescent fibronectin. Surprisingly, we observed substantial, rapid and relatively random migration of individual epithelial cells during branching morphogenesis. We predicted that cell migration would decrease after formation of acini and, indeed, found that rapid cell movements do not occur in SMG from newborn mice. However, in embryonic SMG epithelial cells, we observed an absence of choreographed cell migration, indicating that patterned cell migration alone cannot explain the highly ordered process of branching morphogenesis. We therefore hypothesized a role for directional fibronection assembly in branching. Washout and pulse-chase experiments revealed that older fibronectin accumulates at the base of the clefts and translocates inwards as a wedge, with newer fibronectin assembling behind it. These findings identify a new mechanism for branching morphogenesis involving directional fibronectin translocation superimposed on individual cell dynamics.
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Affiliation(s)
- Melinda Larsen
- Craniofacial Developmental Biology and Regeneration Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, 30 Convent Drive, MSC 4370, Bethesda, MD 20892-4370, USA
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22
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Kawano Y, Kitaoka M, Hamada Y, Walker MM, Waxman J, Kypta RM. Regulation of prostate cell growth and morphogenesis by Dickkopf-3. Oncogene 2006; 25:6528-37. [PMID: 16751809 DOI: 10.1038/sj.onc.1209661] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Wnt signalling plays a critical role in the development of cancer. Recent studies indicate that Wnt signalling is negatively regulated by secreted Wnt antagonists such as secreted frizzled related proteins (sFRPs) and Dickkopfs (Dkks). We compared Dkk family expression levels in normal prostate and prostate cancer cells and found a reduction in Dkk-3 expression in cancer cells. Ectopic expression of Dkk-3 inhibited colony formation in LNCaP and PC3 prostate cancer cell lines and inducible expression of Dkk-3 reduced LNCaP cell proliferation. Moreover, small interfering RNA-mediated downregulation of Dkk-3 enhanced cell cycle progression in untransformed RWPE-1 prostate epithelial cells. Immunohistochemical analysis revealed that Dkk-3 is expressed in a subset of normal prostate gland acini and that Dkk-3 expression is reduced in prostate tumours, particularly those with a high Gleason grade, suggesting a role for Dkk-3 in postmitotic differentiation. Consistent with this, depletion of Dkk-3 disrupted acinar morphogenesis of RWPE-1 cells in a three-dimensional cell culture model. Our results are consistent with the loss of Dkk-3 expression resulting in impairment of glandular structure and uncontrolled prostate epithelial cell (PrEC) proliferation, both of which are crucial for prostate cancer progression.
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Affiliation(s)
- Y Kawano
- 1Prostate Cancer Research Group, Harris Laboratory, Department of Oncology, Division of SORA, Imperial College London, London, UK
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23
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Crema VO, Hamassaki DE, Santos MF. Small Rho GTPases are important for acinus formation in a human salivary gland cell line. Cell Tissue Res 2006; 325:493-500. [PMID: 16639616 DOI: 10.1007/s00441-006-0192-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Accepted: 02/15/2006] [Indexed: 12/21/2022]
Abstract
Rho GTPases participate in a wide variety of signal transduction pathways regulating the actin cytoskeleton, gene expression, cellular migration and proliferation. The aim of this study was to evaluate the role of Rho GTPases in signal transduction pathways during acinus formation in a human salivary gland (HSG) cell line initiated by extracellular matrix (ECM; Matrigel) alone or in combination with epidermal growth factor, basic fibroblast growth factor and lysophosphatidic acid (LPA). Immunohistochemical and Western blotting analyses showed that HSG cells contained RhoA, RhoB, Rac1 and Cdc42 proteins. All growth factors enhanced the effects of ECM on acinus formation, in a pathway dependent on PI3-kinase and Rho GTPases. The role of ROCK, a major RhoA effector, seemed limited to cortical actin polymerization. LPA stimulated cell migration and acinus formation in a PI3-kinase-independent pathway. The results suggest that Rho proteins are important for epithelial-mesenchymal interactions during salivary gland development.
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Affiliation(s)
- Virgínia O Crema
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1524, São Paulo, SP CEP 05508-900, Brazil
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24
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Sakai T, Larsen M, Kogo M, Yamada KM. Salivary Gland Branching Morphogenesis: Exploration of Molecular Mechanisms Using Laser Microdissection and T7-SAGE. J Oral Biosci 2006. [DOI: 10.2330/joralbiosci.48.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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25
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Sakai T, Larsen M, Kogo M, Yamada KM. Salivary Gland Branching Morphogenesis : Exploration of Molecular Mechanisms Using Laser Microdissection and T7-SAGE. J Oral Biosci 2006. [DOI: 10.1016/s1349-0079(06)80012-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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26
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Roth-Kleiner M, Post M. Similarities and dissimilarities of branching and septation during lung development. Pediatr Pulmonol 2005; 40:113-34. [PMID: 15965895 DOI: 10.1002/ppul.20252] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The lungs of small premature babies are at a developmental stage of finalizing their airway tree by a process called branching morphogenesis, and of creating terminal gas exchange units by a mechanism called septation. If the branching process is disturbed, the lung has a propensity to be hypoplastic. If septation is impaired, the terminal gas exchange units, the alveoli, tend to be enlarged and reduced in number, an entity known as bronchopulmonary dysplasia. Here, we review current knowledge of key molecules influencing branching and septation. In particular, we discuss the molecular similarities and dissimilarities between the two processes of airspace enlargement. Understanding of the molecular mechanisms regulating branching and septation may provide perinatologists with targets for improving lung growth and maturation.
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Affiliation(s)
- Matthias Roth-Kleiner
- Lung Biology Program, Hospital for Sick Children Research Institute, and Department of Laboratory Medicine, University of Toronto, Toronto, Ontario, Canada
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27
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Laplante I, Béliveau R, Paquin J. RhoA/ROCK and Cdc42 regulate cell-cell contact and N-cadherin protein level during neurodetermination of P19 embryonal stem cells. ACTA ACUST UNITED AC 2004; 60:289-307. [PMID: 15281068 DOI: 10.1002/neu.20036] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RhoGTPases regulate actin-based signaling cascades and cellular contacts. In neurogenesis, their action modulates cell migration, neuritogenesis, and synaptogenesis. Murine P19 embryonal stem cells differentiate to neurons upon aggregation in the presence of retinoic acid, and we previously showed that RhoA and Cdc42 RhoGTPases are sequentially up-regulated during neuroinduction, suggesting a role at this very early developmental stage. In this work, incubation of differentiating P19 cells with C3 toxin resulted in decreased aggregate cohesion and cadherin protein level. In contrast, C3 effects were not observed in cells overexpressing recombinant dominant active RhoA. On the other hand, C3 did not affect cadherin in uninduced cells and their postmitotic neuronal derivatives, respectively expressing E- and N-cadherin. RhoA is thus influential on cell aggregation and cadherin expression during a sensitive time window that corresponds to the switch of E- to N-cadherin. Cell treatment with Y27632 inhibitor of Rho-associated-kinase ROCK, or advanced overexpression of Cdc42 by gene transfer of a constitutively active form of the protein reproduced C3 effects. RhoA-antisense RNA also reduced cadherin level and the size of cell aggregates, and increased the generation of fibroblast-like cells relative to neurons following neuroinduction. Colchicin, a microtubule disrupter, but not cytochalasin B actin poison, importantly decreased cadherin in neurodifferentiating cells. Overall, our results indicate that the RhoA/ROCK pathway regulates cadherin protein level and cell-cell interactions during neurodetermination, with an impact on the efficiency of the process. The effect on cadherin seems to involve microtubules. The importance of correct timing of RhoA and Cdc42 functional expression in neurogenesis is also raised.
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Affiliation(s)
- Isabel Laplante
- Laboratory of Developmental Neuroendocrinology, Département de chimie et biochimie, Université du Québec à Montréal, C.P. 8888, Succ. Centre-ville, Montreal, Quebec, H3C 3P8, Canada
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28
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Sakai T, Larsen M, Yamada KM. Fibronectin requirement in branching morphogenesis. Nature 2003; 423:876-81. [PMID: 12815434 DOI: 10.1038/nature01712] [Citation(s) in RCA: 388] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2003] [Accepted: 04/21/2003] [Indexed: 01/22/2023]
Abstract
Many organs, including salivary glands, lung and kidney, are formed during embryonic development by epithelial branching. In branching morphogenesis, repetitive epithelial cleft and bud formation create the complex three-dimensional branching structures characteristic of many organs. Although the mechanisms are poorly understood, one might involve the site-specific accumulation of some regulatory protein. Here we show that the extracellular matrix protein fibronectin is essential for cleft formation during the initiation of epithelial branching. Fibronectin messenger RNA and fibrils appeared transiently and focally in forming cleft regions of submandibular salivary-gland epithelia, accompanied by an adjacent loss of cadherin localization. Decreasing the fibronectin concentration by using small interfering RNA and inhibition by anti-fibronectin or anti-integrin antibodies blocked cleft formation and branching. Exogenous fibronectin accelerated cleft formation and branching. Similar effects of fibronectin suppression and augmentation were observed in developing lung and kidney. Mechanistic studies revealed that fibrillar fibronectin can induce cell-matrix adhesions on cultured human salivary epithelial cells with a local loss of cadherins at cell-cell junctions. Thus, fibronectin expression is required for cleft formation in branching morphogenesis associated with the conversion of cell-cell adhesions to cell-matrix adhesions.
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Affiliation(s)
- Takayoshi Sakai
- Craniofacial Developmental Biology and Regeneration Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892-4370, USA
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