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Herring BP, Hoggatt AM, Gupta A, Wo JM. Gastroparesis is associated with decreased FOXF1 and FOXF2 in humans, and loss of FOXF1 and FOXF2 results in gastroparesis in mice. Neurogastroenterol Motil 2019; 31:e13528. [PMID: 30565344 PMCID: PMC6821388 DOI: 10.1111/nmo.13528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 11/02/2018] [Accepted: 11/12/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND AIMS The transcription factors FOXF1 and FOXF2 have been implicated in the development of the gastrointestinal tract but their role in adults or in gastrointestinal diseases is poorly understood. We have recently shown that expression of serum response factor (SRF), a transcription factor whose activity is modulated by FOXF proteins, is decreased in the stomach muscularis of patients with gastroparesis. The aim of the current study was to determine whether FOXF expression is decreased in gastroparesis patients and whether loss of FOXF1 and/or FOXF2 from adult smooth muscle is sufficient to impair gastric emptying in mice. METHODS Full-thickness stomach biopsy samples were collected from control subjects and from patients with gastroparesis. mRNA was isolated from the muscularis externa, and FOXF mRNA expression levels were determined by quantitative reverse transcriptase (RT)-PCR. Foxf1 and Foxf2 were knocked out together and separately from smooth muscle cells in adult mice, and the subsequent effect on liquid gastric emptying and contractile protein expression was determined. KEY RESULTS Expression of FOXF1 and FOXF2 is decreased in smooth muscle tissue from gastroparesis patients. Knockout of Foxf1 and Foxf2 together, but not alone, from mouse smooth muscle resulted in delayed liquid gastric emptying. Foxf1/2 double knockout mice had decreased expression of smooth muscle contractile proteins, SRF, and myocardin in stomach muscularis. CONCLUSIONS AND INFERENCES Our findings suggest that decreased expression of FOXF1 and FOXF2 may be contributing to the impaired gastric emptying seen in gastroparesis patients.
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Affiliation(s)
- B. Paul Herring
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202.,Correspondence: Paul Herring, Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis IN, 46202, Phone: (317) 278-1785, FAX: (317) 274-3318,
| | - April M. Hoggatt
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Anita Gupta
- Department of Medicine, Division of Gastroenterology and Hepatology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - John M. Wo
- Department of Medicine, Division of Gastroenterology and Hepatology, Indiana University School of Medicine, Indianapolis, IN 46202
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2
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Touw K, Chakraborty S, Zhang W, Obukhov AG, Tune JD, Gunst SJ, Herring BP. Altered calcium signaling in colonic smooth muscle of type 1 diabetic mice. Am J Physiol Gastrointest Liver Physiol 2012; 302:G66-76. [PMID: 21979758 PMCID: PMC3345965 DOI: 10.1152/ajpgi.00183.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 09/30/2011] [Indexed: 01/31/2023]
Abstract
Seventy-six percent of diabetic patients develop gastrointestinal symptoms, such as constipation. However, the direct effects of diabetes on intestinal smooth muscle are poorly described. This study aimed to identify the role played by smooth muscle in mediating diabetes-induced colonic dysmotility. To induce type 1 diabetes, mice were injected intraperitoneally with low-dose streptozotocin once a day for 5 days. Animals developed hyperglycemia (>200 mg/dl) 1 wk after the last injection and were euthanized 7-8 wk after the last treatment. Computed tomography demonstrated decreased overall gastrointestinal motility in the diabetic mice. In vitro contractility of colonic smooth muscle rings from diabetic mice was also decreased. Fura-2 ratiometric Ca(2+) imaging showed attenuated Ca(2+) increases in response to KCl stimulation that were associated with decreased light chain phosphorylation in diabetic mice. The diabetic mice also exhibited elevated basal Ca(2+) levels, increased myosin phosphatase targeting subunit 1 expression, and significant changes in expression of Ca(2+) handling proteins, as determined by quantitative RT-PCR and Western blotting. Mice that were hyperglycemic for <1 wk also showed decreased colonic contractile responses that were associated with decreased Ca(2+) increases in response to KCl stimulation, although without an elevation in basal Ca(2+) levels or a significant change in the expression of Ca(2+) signaling molecules. These data demonstrate that type 1 diabetes is associated with decreased depolarization-induced Ca(2+) influx in colonic smooth muscle that leads to attenuated myosin light chain phosphorylation and impaired colonic contractility.
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Affiliation(s)
- Ketrija Touw
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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3
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Nowell CS, Bredenkamp N, Tetélin S, Jin X, Tischner C, Vaidya H, Sheridan JM, Stenhouse FH, Heussen R, Smith AJH, Blackburn CC. Foxn1 regulates lineage progression in cortical and medullary thymic epithelial cells but is dispensable for medullary sublineage divergence. PLoS Genet 2011; 7:e1002348. [PMID: 22072979 PMCID: PMC3207875 DOI: 10.1371/journal.pgen.1002348] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 08/30/2011] [Indexed: 01/12/2023] Open
Abstract
The forkhead transcription factor Foxn1 is indispensable for thymus development, but the mechanisms by which it mediates thymic epithelial cell (TEC) development are poorly understood. To examine the cellular and molecular basis of Foxn1 function, we generated a novel and revertible hypomorphic allele of Foxn1. By varying levels of its expression, we identified a number of features of the Foxn1 system. Here we show that Foxn1 is a powerful regulator of TEC differentiation that is required at multiple intermediate stages of TE lineage development in the fetal and adult thymus. We find no evidence for a role for Foxn1 in TEC fate-choice. Rather, we show it is required for stable entry into both the cortical and medullary TEC differentiation programmes and subsequently is needed at increasing dosage for progression through successive differentiation states in both cortical and medullary TEC. We further demonstrate regulation by Foxn1 of a suite of genes with diverse roles in thymus development and/or function, suggesting it acts as a master regulator of the core thymic epithelial programme rather than regulating a particular aspect of TEC biology. Overall, our data establish a genetics-based model of cellular hierarchies in the TE lineage and provide mechanistic insight relating titration of a single transcription factor to control of lineage progression. Our novel revertible hypomorph system may be similarly applied to analyzing other regulators of development. The thymus is the specialized organ responsible for generating T cells, which are required to regulate and effect immune responses. The unique functions of the thymus are mediated by a diverse array of specialized epithelial cells found only within this organ. These specialized, functionally mature thymic epithelial cells are generated from immature epithelial progenitor cells present in the fetal and adult thymus through a highly regulated process, termed differentiation, that is tightly controlled by specific genes. Foxn1, a protein that is expressed in thymic epithelial cells, is a transcription factor—a protein that regulates how other genes are expressed. Here, we have investigated the role of Foxn1 in generating mature thymic epithelial cells from immature progenitors. We find that Foxn1 is required throughout this process, from the onset of differentiation in progenitor thymic epithelial cells in the developing fetus to the final differentiation steps through which thymic epithelial cells mature to acquire their full functionality. We further find that Foxn1 controls the expression of a variety of genes with different functions in thymic epithelial cells. Overall, our study defines the role of Foxn1 in thymus development at the cellular level and provides insight into how it mediates these functions.
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Affiliation(s)
- Craig S. Nowell
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Nicholas Bredenkamp
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Stéphanie Tetélin
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Xin Jin
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Christin Tischner
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Harsh Vaidya
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Julie M. Sheridan
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Frances Hogg Stenhouse
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Raphaela Heussen
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew J. H. Smith
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - C. Clare Blackburn
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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4
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Elia L, Quintavalle M, Zhang J, Contu R, Cossu L, Latronico MVG, Peterson KL, Indolfi C, Catalucci D, Chen J, Courtneidge SA, Condorelli G. The knockout of miR-143 and -145 alters smooth muscle cell maintenance and vascular homeostasis in mice: correlates with human disease. Cell Death Differ 2009; 16:1590-8. [PMID: 19816508 PMCID: PMC3014107 DOI: 10.1038/cdd.2009.153] [Citation(s) in RCA: 434] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mechanisms controlling vascular smooth muscle cell (VSMC) plasticity and renewal still remain to be elucidated completely. A class of small RNAs called microRNAs (miRs) regulate gene expression at the post-transcriptional level. Here, we show a critical role of the miR-143/145 cluster in SMC differentiation and vascular pathogenesis, also through the generation of a mouse model of miR-143 and -145 knockout (KO). We determined that the expression of miR-143 and -145 is decreased in acute and chronic vascular stress (transverse aortic constriction and in aortas of the ApoE KO mouse). In human aortic aneurysms, the expression of miR-143 and -145 was significantly decreased compared with control aortas. In addition, overexpression of miR-143 and -145 decreased neointimal formation in a rat model of acute vascular injury. An in-depth analysis of the miR-143/145 KO mouse model showed that this miR cluster is expressed mostly in the SMC compartment, both during development and postnatally, in vessels and SMC-containing organs. Loss of miR-143 and miR-145 expression induces structural modifications of the aorta, because of an incomplete differentiation of VSMCs. In conclusion, our results show that the miR-143/145 gene cluster has a critical role during SMC differentiation and strongly suggest its involvement in the reversion of the VSMC differentiation phenotype that occurs during vascular disease.
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Affiliation(s)
- Leonardo Elia
- Department of Medicine, Division of Cardiology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
- Institute of Biomedical Technologies, Consiglio Nazionale delle Ricerche, via Fratelli Cervi 93, 20138 Milan, Italy
| | - Manuela Quintavalle
- Burnham Institute for Medical Research 10901 North Torrey Pines Road, La Jolla, CA 92037
| | - Jianlin Zhang
- Department of Medicine, Division of Cardiology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Riccardo Contu
- I.R.C.C.S. MultiMedica Hospital, via Gaudenzio Fantoli 16/15, 20138 Milan, Italy
| | - Luca Cossu
- I.R.C.C.S. MultiMedica Hospital, via Gaudenzio Fantoli 16/15, 20138 Milan, Italy
| | | | - Kirk L. Peterson
- Department of Medicine, Division of Cardiology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Ciro Indolfi
- University Magna Graecia, 88100 Catanzaro, Italy
| | - Daniele Catalucci
- Institute of Biomedical Technologies, Consiglio Nazionale delle Ricerche, via Fratelli Cervi 93, 20138 Milan, Italy
- I.R.C.C.S. MultiMedica Hospital, via Gaudenzio Fantoli 16/15, 20138 Milan, Italy
| | - Ju Chen
- Department of Medicine, Division of Cardiology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Sara A. Courtneidge
- Burnham Institute for Medical Research 10901 North Torrey Pines Road, La Jolla, CA 92037
| | - Gianluigi Condorelli
- Department of Medicine, Division of Cardiology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
- Institute of Biomedical Technologies, Consiglio Nazionale delle Ricerche, via Fratelli Cervi 93, 20138 Milan, Italy
- I.R.C.C.S. MultiMedica Hospital, via Gaudenzio Fantoli 16/15, 20138 Milan, Italy
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Sáenz Robles MT, Pipas JM. T antigen transgenic mouse models. Semin Cancer Biol 2009; 19:229-35. [PMID: 19505650 DOI: 10.1016/j.semcancer.2009.02.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 02/03/2009] [Accepted: 02/06/2009] [Indexed: 01/12/2023]
Abstract
The study of polyomavirus has benefited immensely from two scientific methodologies, cell culture and in vitro studies on one side and the use of transgenic mice as experimental models on the other. Both approaches allowed us to identify cellular products targeted by the viruses, the consequences of these interactions at the phenotypic and molecular level, and thus the potential roles of the targets within their normal cellular context. In particular, cell culture and in vitro reports suggest a model explaining partially how SV40 large T antigen contributes to oncogenic transformation. In most cases, T antigen induces cell cycle entry by inactivation of the Rb proteins (pRb, p130, and p107), thus activating E2F-dependent transcription and subsequent S-phase entry. Simultaneously, T antigen blocks p53 activity and therefore prevents the ensuing cell-cycle arrest and apoptosis. For the most part, studies of T antigen expression in transgenic mice support this model, but the use of T antigen mutants and their expression in different tissue and cell type settings have expanded our knowledge of the model system and raised important questions regarding tumorigenic mechanisms functioning in vivo.
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6
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Touw K, Hoggatt AM, Simon G, Herring BP. Hprt-targeted transgenes provide new insights into smooth muscle-restricted promoter activity. Am J Physiol Cell Physiol 2006; 292:C1024-32. [PMID: 17079332 DOI: 10.1152/ajpcell.00445.2006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Mouse telokin and SM22alpha promoters have previously been shown to direct smooth muscle cell-specific expression of transgenes in vivo in adult mice. However, the activity of these promoters is highly dependent on the integration site of the transgene. In the current study, we found that the ectopic expression of telokin promoter transgenes could be abolished by flanking the transgene with insulator elements from the H19 gene. However, the insulator elements did not increase the proportion of mouse lines that exhibited consistent, detectable levels of transgene expression. In contrast, when transgenes were targeted to the hprt locus, both telokin and SM22alpha promoters resulted in reproducible patterns and levels of transgene expression in all lines of mice examined. Telokin promoter transgene expression was restricted to smooth muscle tissues in adult and embryonic mice. As reported previously, SM22alpha transgenes were expressed at high levels specifically in arterial smooth muscle cells; however, in contrast to randomly integrated transgenes, the hprt-targeted SM22alpha transgenes were also expressed at high levels in smooth muscle cells in veins, bladder, and gallbladder. Using hprt-targeted transgenes, we further analyzed elements within the telokin promoter required for tissue specific activity in vivo. Analysis of these transgenes revealed that the CArG element in the telokin promoter is required for promoter activity in all tissues and that the CArG element and adjacent AT-rich region are sufficient to drive transgene expression in bladder but not intestinal smooth muscle cells.
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Affiliation(s)
- Ketrija Touw
- Dept. of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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7
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Ahuja D, Sáenz-Robles MT, Pipas JM. SV40 large T antigen targets multiple cellular pathways to elicit cellular transformation. Oncogene 2005; 24:7729-45. [PMID: 16299533 DOI: 10.1038/sj.onc.1209046] [Citation(s) in RCA: 402] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
DNA tumor viruses such as simian virus 40 (SV40) express dominant acting oncoproteins that exert their effects by associating with key cellular targets and altering the signaling pathways they govern. Thus, tumor viruses have proved to be invaluable aids in identifying proteins that participate in tumorigenesis, and in understanding the molecular basis for the transformed phenotype. The roles played by the SV40-encoded 708 amino-acid large T antigen (T antigen), and 174 amino acid small T antigen (t antigen), in transformation have been examined extensively. These studies have firmly established that large T antigen's inhibition of the p53 and Rb-family of tumor suppressors and small T antigen's action on the pp2A phosphatase, are important for SV40-induced transformation. It is not yet clear if the Rb, p53 and pp2A proteins are the only targets through which SV40 transforms cells, or whether additional targets await discovery. Finally, expression of SV40 oncoproteins in transgenic mice results in effects ranging from hyperplasia to invasive carcinoma accompanied by metastasis, depending on the tissue in which they are expressed. Thus, the consequences of SV40 action on these targets depend on the cell type being studied. The identification of additional cellular targets important for transformation, and understanding the molecular basis for the cell type-specific action of the viral T antigens are two important areas through which SV40 will continue to contribute to our understanding of cancer.
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Affiliation(s)
- Deepika Ahuja
- Department of Biological Sciences, University of Pittsburgh, PA 15260, USA
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8
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Markovics JA, Carroll PA, Robles MTS, Pope H, Coopersmith CM, Pipas JM. Intestinal dysplasia induced by simian virus 40 T antigen is independent of p53. J Virol 2005; 79:7492-502. [PMID: 15919904 PMCID: PMC1143657 DOI: 10.1128/jvi.79.12.7492-7502.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Transgenic mice expressing simian virus 40 large T antigen in enterocytes develop intestinal hyperplasia that progresses to dysplasia with age. Hyperplasia is dependent on T antigen binding to the retinoblastoma (pRb) family of tumor suppressor proteins. Mice expressing a truncated T antigen that inactivates the pRb-family, but is defective for binding p53, exhibit hyperplasia but do not progress to dysplasia. We hypothesized that the inhibition of the pRb family leads to entry of enterocytes into the cell cycle, resulting in hyperplasia, while inactivation of p53 is required for progression to dysplasia. Therefore, we examined T antigen/p53 complexes from the intestines of transgenic mice. We found that T antigen did not induce p53 stabilization, and we could not detect T antigen/p53 complexes in villus enterocytes. In contrast, T antigen expression led to a large increase in the levels of the cyclin-dependent kinase inhibitor p21. Furthermore, mice in which pRb was inactivated by a truncated T antigen in a p53 null background exhibited intestinal hyperplasia but no progression to dysplasia. These data indicate that loss of p53 function does not play a role in T antigen-induced dysplasia in the intestine. Rather, some unknown function of T antigen is essential for progression beyond hyperplasia.
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Affiliation(s)
- Jennifer A Markovics
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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9
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Sindermann JR, Babij P, Klink JC, Köbbert C, Plenz G, Ebbing J, Fan L, March KL. Smooth muscle-specific expression of SV40 large TAg induces SMC proliferation causing adaptive arterial remodeling. Am J Physiol Heart Circ Physiol 2002; 283:H2714-24. [PMID: 12388294 DOI: 10.1152/ajpheart.00077.2002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
To study the effects of enhanced smooth muscle cell (SMC) proliferation on arterial vessel geometry in the absence of vessel trauma, we developed a transgenic mouse model expressing SV40 large T antigen under control of the 2.3-kb smooth muscle-myosin heavy chain promoter. Transgenic mice studied at ages from 3 to 13 wk showed a 3.2-fold increase in arterial wall SMC density, with 28% of SMC exhibiting proliferative cell nuclear antigen staining, confirming enhanced SMC proliferation, which was accompanied by two- to threefold increases in arterial wall areas (P < 0.05). Remarkably, despite increased vessel wall mass, the lumen area was not compromised, but rather was increased. A tightly conserved linear relationship was found between arterial circumference and wall thickness with slopes of 0.036 for both transgenics (r = 0.93, P < 0.01) and controls (r = 0.77, P < 0.01), suggesting the hypothesis that the conservation of wall stress functions as a primary determinant of adaptive arterial remodeling. This establishes a new model of adaptive vessel remodeling occurring in response to a proliferative input in the absence of mechanical injury or primary flow perturbation.
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MESH Headings
- Adaptation, Physiological/genetics
- Animals
- Antigens, Polyomavirus Transforming/biosynthesis
- Antigens, Polyomavirus Transforming/genetics
- Arteries/cytology
- Arteries/metabolism
- Cell Count
- Cell Division/genetics
- Cell Division/physiology
- Gene Expression/physiology
- Mice
- Mice, Inbred C3H
- Mice, Transgenic
- Models, Animal
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Proliferating Cell Nuclear Antigen/biosynthesis
- Promoter Regions, Genetic
- Rabbits
- Simian virus 40/genetics
- Smooth Muscle Myosins/genetics
- Stress, Mechanical
- Vascular Patency
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Affiliation(s)
- Jürgen R Sindermann
- Krannert Institute of Cardiology and Indiana Center for Vascular Biology and Medicine, Indiana University Medical Center, Indianapolis 46202, USA.
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10
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Condon J, Yin S, Mayhew B, Word RA, Wright WE, Shay JW, Rainey WE. Telomerase immortalization of human myometrial cells. Biol Reprod 2002; 67:506-14. [PMID: 12135889 DOI: 10.1095/biolreprod67.2.506] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Several strategies have been described for the primary culture of human myometrial cells. However, primary cultures of myometrial cells have a limited life span, making continual tissue acquisition and cell isolation necessary. Recent studies have demonstrated that cell culture life span is related to chromosomal telomere length, and cellular senescence results from progressive telomere shortening and the lack of telomerase expression. Transfection of cells with expression vectors containing the human telomerase reverse transcriptase (hTERT) maintains telomere length and effectively gives normal cells an unlimited life span in culture. In addition, hTERT extends the life span of cultured cells far beyond normal senescence without causing neoplastic transformation. In the present study, we developed a cell line from hTERT-infected myometrial cells (hTERT-HM). Cells were isolated from myometrial tissue obtained from women undergoing hysterectomy, and retroviral infection was used to express the catalytic subunit of telomerase in myometrial cells. Cells expressing hTERT have been in continuous culture for >10 mo, whereas the control culture senesced after approximately 2 mo. Telomerase activity was monitored in cells with a polymerase chain reaction-based telomerase activity assay. Telomerase-expressing cells contained mRNA for alpha smooth muscle actin, smoothelin, oxytocin receptor, and estrogen receptor alpha, but the estrogen receptor beta receptor was lost. Immunoblotting analysis identified the expression of calponin, caldesmon, alpha smooth muscle actin, and oxytocin receptor. Although estrogen receptor expression was below the level of detection with immunoblotting, transfection experiments performed with reporter constructs driven by estrogen response elements demonstrated estrogen responsiveness in the hTERT-HM. In addition, treatment of hTERT-HM with oxytocin caused a concentration-dependent increase in intracellular calcium levels, confirming the presence of functional oxytocin receptors. Myometrial cells immortalized with hTERT retained markers of differentiation that are observed in primary cultures of smooth muscle cells. The expression of various smooth muscle/myometrium cell markers suggests that these cells may be an appropriate model system to study certain aspects of human myometrial function.
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Affiliation(s)
- Jennifer Condon
- Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9032, USA
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11
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Affiliation(s)
- M T Sáenz-Robles
- Department of Biological Sciences. University of Pittsburgh, Pittsburgh, PA 15260, USA
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12
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Gallagher PJ, Jin Y, Killough G, Blue EK, Lindner V. Alterations in expression of myosin and myosin light chain kinases in response to vascular injury. Am J Physiol Cell Physiol 2000; 279:C1078-87. [PMID: 11003588 PMCID: PMC2824508 DOI: 10.1152/ajpcell.2000.279.4.c1078] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Histochemical analysis of balloon-injured rat carotid arteries revealed a coordinated expression of nonmuscle myosin heavy chain-A and -B (NM-A and NM-B) in response to injury. Expression of these nonmuscle myosin forms shifts from the media to the adventitia and intima. In contrast, expression of smooth muscle myosin heavy chain-1 (SM-1) within the media is not altered, whereas smooth muscle myosin heavy chain-2 (SM-2) expression declines. Western blotting shows a statistically significant increase in expression of NM-A that occurs within 6 h in response to carotid injury, suggesting this myosin form may be an appropriate experimental marker for proliferating, migrating cells in injured vessels. No overall change in the relative expression level of NM-B was detected, suggesting that compensatory declines in media expression are balanced by increases in the intima and adventitia. Expression of SM-1 did not change in response to injury, whereas the expression of SM-2 significantly declined between 24 h and 7 days. Expression of myosin light chain kinase is also negatively regulated, and the decline in its expression parallels downregulation of SM-2.
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Affiliation(s)
- P J Gallagher
- Department of Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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