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Haller M, Yin Y, Haller G, Li T, Li Q, Lamb LE, Ma L. Streamlined identification of clinically and functionally relevant genetic regulators of lower-tract urogenital development. Proc Natl Acad Sci U S A 2024; 121:e2309466121. [PMID: 38300866 PMCID: PMC10861909 DOI: 10.1073/pnas.2309466121] [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: 06/06/2023] [Accepted: 12/18/2023] [Indexed: 02/03/2024] Open
Abstract
Congenital anomalies of the lower genitourinary (LGU) tract are frequently comorbid due to genetically linked developmental pathways, and are among the most common yet most socially stigmatized congenital phenotypes. Genes involved in sexual differentiation are prime candidates for developmental anomalies of multiple LGU organs, but insufficient prospective screening tools have prevented the rapid identification of causative genes. Androgen signaling is among the most influential modulators of LGU development. The present study uses SpDamID technology in vivo to generate a comprehensive map of the pathways actively regulated by the androgen receptor (AR) in the genitalia in the presence of the p300 coactivator, identifying wingless/integrated (WNT) signaling as a highly enriched AR-regulated pathway in the genitalia. Transcription factor (TF) hits were then assayed for sexually dimorphic expression at two critical time points and also cross-referenced to a database of clinically relevant copy number variations to identify 252 TFs exhibiting copy variation in patients with LGU phenotypes. A subset of 54 TFs was identified for which LGU phenotypes are statistically overrepresented as a proportion of total observed phenotypes. The 252 TF hitlist was then subjected to a functional screen to identify hits whose silencing affects genital mesenchymal growth rates. Overlap of these datasets results in a refined list of 133 TFs of both functional and clinical relevance to LGU development, 31 of which are top priority candidates, including the well-documented renal progenitor regulator, Sall1. Loss of Sall1 was examined in vivo and confirmed to be a powerful regulator of LGU development.
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Affiliation(s)
- Meade Haller
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
| | - Yan Yin
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
| | - Gabe Haller
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO63110
| | - Tian Li
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
| | - Qiufang Li
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
| | - Laura E. Lamb
- Department of Urology, William Beaumont School of Medicine, Oakland University, Rochester, MI48309
| | - Liang Ma
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
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2
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Inducible expression of Wnt7b promotes bone formation in aged mice and enhances fracture healing. Bone Res 2020; 8:4. [PMID: 32047703 PMCID: PMC6997361 DOI: 10.1038/s41413-019-0081-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 10/14/2019] [Accepted: 11/28/2019] [Indexed: 02/07/2023] Open
Abstract
There remain unmet clinical needs for safe and effective bone anabolic therapies to treat aging-related osteoporosis and to improve fracture healing in cases of nonunion or delayed union. Wnt signaling has emerged as a promising target pathway for developing novel bone anabolic drugs. Although neutralizing antibodies against the Wnt antagonist sclerostin have been tested, Wnt ligands themselves have not been fully explored as a potential therapy. Previous work has demonstrated Wnt7b as an endogenous ligand upregulated during osteoblast differentiation, and that Wnt7b overexpression potently stimulates bone accrual in the mouse. The earlier studies however did not address whether Wnt7b could promote bone formation when specifically applied to aged or fractured bones. Here we have developed a doxycycline-inducible strategy where Wnt7b is temporally induced in the bones of aged mice or during fracture healing. We report that forced expression of Wnt7b for 1 month starting at 15 months of age greatly stimulated trabecular and endosteal bone formation, resulting in a marked increase in bone mass. We further tested the effect of Wnt7b on bone healing in a murine closed femur fracture model. Induced expression of Wnt7b at the onset of fracture did not affect the initial cartilage formation but promoted mineralization of the subsequent bone callus. Thus, targeted delivery of Wnt7b to aged bones or fracture sites may be explored as a potential therapy.
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3
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Sakagami N, Matsushita Y, Syklawer-Howle S, Kronenberg HM, Ono W, Ono N. Msx2 Marks Spatially Restricted Populations of Mesenchymal Precursors. J Dent Res 2018; 97:1260-1267. [PMID: 29746183 DOI: 10.1177/0022034518771014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Craniofacial development requires a set of patterning codes that define the identities of postmigratory mesenchymal cells in a region-specific manner, in which locally expressed morphogens, including fibroblast growth factors (FGFs) and bone morphogenetic proteins (BMPs), provide instructive cues. Msx2, a bona fide target of BMP signaling, is a transcription factor regulating Runx2 and osterix (Osx), whose mutations are associated with cranial deformities in humans. Here we show that Msx2 defines osteo-chondro precursor cells in specific regions of the craniofacial mesenchyme at the postmigratory stage, particularly in the mandibular process and the posterior cranial vault. Analysis of Msx2-creER mice revealed that early mesenchymal cells in proximity to the BMP4-expressing mesenchyme were marked upon tamoxifen injection, and their descendants contributed to diverse types of mesenchymal cells in the later stage, such as chondrocytes and perichondrial cells of the transient cartilage, as well as osteoblasts and suture mesenchymal cells. By contrast, Osx-creER marked osteoblast precursors at the later stage, and their descendants continued to become osteoblasts well into the postnatal stage. Therefore, Msx2 marks spatially restricted populations of mesenchymal precursor cells with diverse differentiation potential, suggesting that extrinsic molecular cues can dictate the nature of postmigratory mesenchymal cells in craniofacial development.
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Affiliation(s)
- N Sakagami
- 1 University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Y Matsushita
- 1 University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - S Syklawer-Howle
- 1 University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - H M Kronenberg
- 2 Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - W Ono
- 1 University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - N Ono
- 1 University of Michigan School of Dentistry, Ann Arbor, MI, USA
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4
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Huang CC, Orvis GD, Kwan KM, Behringer RR. Lhx1 is required in Müllerian duct epithelium for uterine development. Dev Biol 2014; 389:124-36. [PMID: 24560999 DOI: 10.1016/j.ydbio.2014.01.025] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 02/08/2023]
Abstract
The female reproductive tract organs of mammals, including the oviducts, uterus, cervix and upper vagina, are derived from the Müllerian ducts, a pair of epithelial tubes that form within the mesonephroi. The Müllerian ducts form in a rostral to caudal manner, guided by and dependent on the Wolffian ducts that have already formed. Experimental embryological studies indicate that caudal elongation of the Müllerian duct towards the urogenital sinus occurs in part by proliferation at the ductal tip. The molecular mechanisms that regulate the elongation of the Müllerian duct are currently unclear. Lhx1 encodes a LIM-homeodomain transcription factor that is essential for male and female reproductive tract development. Lhx1 is expressed in both the Wolffian and Müllerian ducts. Wolffian duct-specific knockout of Lhx1 results in degeneration of the Wolffian duct and consequently the non-cell-autonomous loss of the Müllerian duct. To determine the role of Lhx1 specifically in the Müllerian duct epithelium, we performed a Müllerian duct-specific knockout study using Wnt7a-Cre mice. Loss of Lhx1 in the Müllerian duct epithelium led to a block in Müllerian duct elongation and uterine hypoplasia characterized by loss of the entire endometrium (luminal and glandular epithelium and stroma) and inner circular but not the outer longitudinal muscle layer. Time-lapse imaging and molecular analyses indicate that Lhx1 acts cell autonomously to maintain ductal progenitor cells for Müllerian duct elongation. These studies identify LHX1 as the first transcription factor that is essential in the Müllerian duct epithelial progenitor cells for female reproductive tract development. Furthermore, these genetic studies demonstrate the requirement of epithelial-mesenchymal interactions for uterine tissue compartment differentiation.
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Affiliation(s)
- Cheng-Chiu Huang
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Grant D Orvis
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Kin Ming Kwan
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, PR China
| | - Richard R Behringer
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
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Chen J, Tu X, Esen E, Joeng KS, Lin C, Arbeit JM, Rüegg MA, Hall MN, Ma L, Long F. WNT7B promotes bone formation in part through mTORC1. PLoS Genet 2014; 10:e1004145. [PMID: 24497849 PMCID: PMC3907335 DOI: 10.1371/journal.pgen.1004145] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 12/12/2013] [Indexed: 11/30/2022] Open
Abstract
WNT signaling has been implicated in both embryonic and postnatal bone formation. However, the pertinent WNT ligands and their downstream signaling mechanisms are not well understood. To investigate the osteogenic capacity of WNT7B and WNT5A, both normally expressed in the developing bone, we engineered mouse strains to express either protein in a Cre-dependent manner. Targeted induction of WNT7B, but not WNT5A, in the osteoblast lineage dramatically enhanced bone mass due to increased osteoblast number and activity; this phenotype began in the late-stage embryo and intensified postnatally. Similarly, postnatal induction of WNT7B in Runx2-lineage cells greatly stimulated bone formation. WNT7B activated mTORC1 through PI3K-AKT signaling. Genetic disruption of mTORC1 signaling by deleting Raptor in the osteoblast lineage alleviated the WNT7B-induced high-bone-mass phenotype. Thus, WNT7B promotes bone formation in part through mTORC1 activation. The human bone tissue is of considerable regenerative capacity as reflected in bone remodeling and in fracture healing. However, bone tissue regeneration deteriorates with age, and tremendous unmet medical needs exist for safe and effective strategies to stimulate bone formation in older individuals commonly inflicted with osteoporosis or osteopenia. WNT signaling has emerged as a promising target pathway for developing novel bone anabolic therapeutics. Identifying bone-promoting WNT ligands and elucidating the underlying mechanisms may lead to useful therapeutic targets. The present study reports that WNT7B potently enhances bone formation through activation of mTORC1 in the mouse.
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Affiliation(s)
- Jianquan Chen
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Xiaolin Tu
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Emel Esen
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Kyu Sang Joeng
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Congxin Lin
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Jeffrey M. Arbeit
- Department of Surgery, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | | | | | - Liang Ma
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Fanxin Long
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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6
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Lin C, Yin Y, Stemler K, Humphrey P, Kibel AS, Mysorekar IU, Ma L. Constitutive β-catenin activation induces male-specific tumorigenesis in the bladder urothelium. Cancer Res 2013; 73:5914-25. [PMID: 23928991 DOI: 10.1158/0008-5472.can-12-4198] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The incidence for bladder urothelial carcinoma, a common malignancy of the urinary tract, is about three times higher in men than in women. Although this gender difference has been primarily attributed to differential exposures, it is likely that underlying biologic causes contribute to the gender inequality. In this study, we report a transgenic mouse bladder tumor model upon induction of constitutively activated β-catenin signaling in the adult urothelium. We showed that the histopathology of the tumors observed in our model closely resembled that of the human low-grade urothelial carcinoma. In addition, we provided evidence supporting the KRT5-positive;KRT7-negative (KRT5(+); KRT7(-)) basal cells as the putative cells-of-origin for β-catenin-induced luminal tumor. Intriguingly, the tumorigenesis in this model showed a marked difference between opposite sexes; 40% of males developed macroscopically detectable luminal tumors in 12 weeks, whereas only 3% of females developed tumors. We investigated the mechanisms underlying this sexual dimorphism in pathogenesis and showed that nuclear translocation of the androgen receptor (AR) in the urothelial cells is a critical mechanism contributing to tumor development in male mice. Finally, we carried out global gene profiling experiments and defined the molecular signature for the β-catenin-induced tumorigenesis in males. Altogether, we have established a model for investigating sexual dimorphism in urothelial carcinoma development, and implicated synergy between β-catenin signaling and androgen/AR signaling in carcinogenesis of the basal urothelial cells.
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Affiliation(s)
- Congxing Lin
- Authors' Affiliations: Division of Dermatology, Department of Medicine, Departments of Obstetrics and Gynecology, and Pathology and Immunology, Washington University in St. Louis, St. Louis, Missouri; and Division of Urology, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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7
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Activation of NFAT signaling establishes a tumorigenic microenvironment through cell autonomous and non-cell autonomous mechanisms. Oncogene 2013; 33:1840-9. [PMID: 23624921 DOI: 10.1038/onc.2013.132] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 02/27/2013] [Accepted: 03/11/2013] [Indexed: 11/09/2022]
Abstract
NFAT (the nuclear factor of activated T cells) upregulation has been linked to cellular transformation intrinsically, but it is unclear whether and how tissue cells with NFAT activation change the local environment for tumor initiation and progression. Direct evidence showing NFAT activation initiates primary tumor formation in vivo is also lacking. Using inducible transgenic mouse systems, we show that tumors form in a subset of, but not all, tissues with NFATc1 activation, indicating that NFAT oncogenic effects depend on cell types and tissue contexts. In NFATc1-induced skin and ovarian tumors, both cells with NFATc1 activation and neighboring cells without NFATc1 activation have significant upregulation of c-Myc and activation of Stat3. Besides known and suspected NFATc1 targets, such as Spp1 and Osm, we have revealed the early upregulation of a number of cytokines and cytokine receptors, as key molecular components of an inflammatory microenvironment that promotes both NFATc1(+) and NFATc1(-) cells to participate in tumor formation. Cultured cells derived from NFATc1-induced tumors were able to establish a tumorigenic microenvironment, similar to that of the primary tumors, in an NFATc1-dependent manner in nude mice with T-cell deficiency, revealing an addiction of these tumors to NFATc1 activation and downplaying a role for T cells in the NFATc1-induced tumorigenic microenvironment. These findings collectively suggest that beyond the cell autonomous effects on the upregulation of oncogenic proteins, NFATc1 activation has non-cell autonomous effects through the establishment of a promitogenic microenvironment for tumor growth. This study provides direct evidence for the ability of NFATc1 in inducing primary tumor formation in vivo and supports targeting NFAT signaling in anti-tumor therapy.
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8
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Lin C, Yin Y, Bell SM, Veith GM, Chen H, Huh SH, Ornitz DM, Ma L. Delineating a conserved genetic cassette promoting outgrowth of body appendages. PLoS Genet 2013; 9:e1003231. [PMID: 23358455 PMCID: PMC3554569 DOI: 10.1371/journal.pgen.1003231] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 11/26/2012] [Indexed: 12/27/2022] Open
Abstract
The acquisition of the external genitalia allowed mammals to cope with terrestrial-specific reproductive needs for internal fertilization, and thus it represents one of the most fundamental steps in evolution towards a life on land. How genitalia evolved remains obscure, and the key to understanding this process may lie in the developmental genetics that underpins the early establishment of the genital primordium, the genital tubercle (GT). Development of the GT is similar to that of the limb, which requires precise regulation from a distal signaling epithelium. However, whether outgrowth of the GT and limbs is mediated by common instructive signals remains unknown. In this study, we used comprehensive genetic approaches to interrogate the signaling cascade involved in GT formation in comparison with limb formation. We demonstrate that the FGF ligand responsible for GT development is FGF8 expressed in the cloacal endoderm. We further showed that forced Fgf8 expression can rescue limb and GT reduction in embryos deficient in WNT signaling activity. Our studies show that the regulation of Fgf8 by the canonical WNT signaling pathway is mediated in part by the transcription factor SP8. Sp8 mutants elicit appendage defects mirroring WNT and FGF mutants, and abolishing Sp8 attenuates ectopic appendage development caused by a gain-of-function β-catenin mutation. These observations indicate that a conserved WNT-SP8-FGF8 genetic cassette is employed by both appendages for promoting outgrowth, and suggest a deep homology shared by the limb and external genitalia. Mammalian limbs and external genitalia are body appendages specialized for locomotion and internal fertilization, respectively. Despite their marked anatomical and functional differences, development of the limb and external genitalia appears to involve similar genetic controls, and some have suggested that regulatory mechanisms common to both might be evolutionarily linked. One essential aspect for appendage development is the establishment and maintenance of a separated proximodistal developmental axis apart from the main body axis, which is often instructed by a distal signaling epithelium. Herein, we adopted comprehensive mouse genetic approaches to investigate regulatory mechanisms underlying the distal signaling center in the limb and the GT, and uncovered a conserved genetic cassette that is utilized by both paired and unpaired appendages to establish a distal signaling center in the epithelium that mediates subsequent proximodistal outgrowth. Our results further suggested that the evolution of the external genital organ involved co-option of the same genetic program underpinning limb development.
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Affiliation(s)
- Congxing Lin
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Yan Yin
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Sheila M. Bell
- Perinatal Institute of Cincinnati Children's Hospital Medical Center, Division of Neonatology-and Pulmonary Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - G. Michael Veith
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Hong Chen
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Sung-Ho Huh
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - David M. Ornitz
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Liang Ma
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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9
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Lallemand Y, Moreau J, Cloment CS, Vives FL, Robert B. Generation and characterization of a tamoxifen inducible Msx1(CreERT2) knock-in allele. Genesis 2012; 51:110-9. [PMID: 23090744 DOI: 10.1002/dvg.22350] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 10/01/2012] [Accepted: 10/12/2012] [Indexed: 11/08/2022]
Abstract
Msx1, a member of the Msx gene family, encodes a homeodomain transcription factor and plays critical roles during mouse development in numerous organs. By homologous recombination, we generated a new Msx1 allele (Msx1(CreERT2) ) in which the CreERT2 fusion protein is produced in place of the endogenous Msx1 protein. Using different reporter mouse strains and appropriate tamoxifen treatments, we show that, in mice bearing the Msx1(CrERT2) allele, CreERT2 is capable to induce loxP genomic recombination specifically in Msx1-expressing cells and that this can be obtained during embryonic development as well as after birth. These results show that this new mouse line can be used for lineage tracing of Msx1-expressing cells and their descendants and, combined with Cre-inducible Msx null alleles, for the analysis of Msx1 and/or Msx2 functions in the Msx1-expressing organs, in a time-dependant manner.
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Affiliation(s)
- Yvan Lallemand
- Institut Pasteur, Unité de Génétique Moléculaire de la Morphogenèse, CNRS URA 2578, F-75015 Paris, France
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10
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Lin C, Hindes A, Burns CJ, Koppel AC, Kiss A, Yin Y, Ma L, Blumenberg M, Khnykin D, Jahnsen FL, Crosby SD, Ramanan N, Efimova T. Serum response factor controls transcriptional network regulating epidermal function and hair follicle morphogenesis. J Invest Dermatol 2012; 133:608-617. [PMID: 23151848 DOI: 10.1038/jid.2012.378] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Serum response factor (SRF) is a transcription factor that regulates the expression of growth-related immediate-early, cytoskeletal, and muscle-specific genes to control growth, differentiation, and cytoskeletal integrity in different cell types. To investigate the role for SRF in epidermal development and homeostasis, we conditionally knocked out SRF in epidermal keratinocytes. We report that SRF deletion disrupted epidermal barrier function leading to early postnatal lethality. Mice lacking SRF in epidermis displayed morphogenetic defects, including an eye-open-at-birth phenotype and lack of whiskers. SRF-null skin exhibited abnormal morphology, hyperplasia, aberrant expression of differentiation markers and transcriptional regulators, anomalous actin organization, enhanced inflammation, and retarded hair follicle (HF) development. Transcriptional profiling experiments uncovered profound molecular changes in SRF-null E17.5 epidermis and revealed that many previously identified SRF target CArG box-containing genes were markedly upregulated in SRF-null epidermis, indicating that SRF may function to repress transcription of a subset of its target genes in epidermis. Remarkably, when transplanted onto nude mice, engrafted SRF-null skin lacked hair but displayed normal epidermal architecture with proper expression of differentiation markers, suggesting that although keratinocyte SRF is essential for HF development, a cross-talk between SRF-null keratinocytes and the surrounding microenvironment is likely responsible for the barrier-deficient mutant epidermal phenotype.
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Affiliation(s)
- Congxing Lin
- Division of Dermatology, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA
| | - Anna Hindes
- Division of Dermatology, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA
| | - Carole J Burns
- Division of Dermatology, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA
| | - Aaron C Koppel
- Division of Dermatology, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA
| | - Alexi Kiss
- Division of Dermatology, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA
| | - Yan Yin
- Division of Dermatology, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA
| | - Liang Ma
- Division of Dermatology, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA
| | - Miroslav Blumenberg
- R. O. Perelman Department of Dermatology, NYU School of Medicine, New York, New York, USA
| | - Denis Khnykin
- Department of Pathology and Centre for Immune Regulation, University Hospital and University of Oslo, Oslo, Norway
| | - Frode L Jahnsen
- Department of Pathology and Centre for Immune Regulation, University Hospital and University of Oslo, Oslo, Norway
| | - Seth D Crosby
- Department of Genetics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Narendrakumar Ramanan
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Tatiana Efimova
- Division of Dermatology, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA.
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11
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Schneider MR. Genetic mouse models for skin research: strategies and resources. Genesis 2012; 50:652-64. [PMID: 22467532 DOI: 10.1002/dvg.22029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/20/2012] [Accepted: 03/24/2012] [Indexed: 12/16/2022]
Abstract
A number of features contributed to establishing the mouse as the favorite model organism for skin research: the genetic and pathophysiological similarities to humans, the small size and relatively short reproductive period, meaning low maintenance costs, and the availability of sophisticated tools for manipulating the genome, gametes, and embryos. While initial studies depended on strains displaying skin abnormalities due to spontaneous genetic mutations, the availability of the transgenic and knockout technologies and their astonishing perfection during the last decades allowed the development of mouse lines permitting any imaginable genetic modification including gene inactivation, substitution, modification, or overexpression. While these technologies have already contributed to the functional analysis of several genes and processes related to skin research, continued progress requires understanding, awareness, and access to these mouse resources. This review will identify the strategies currently employed for the genetic manipulation of mice in skin research, and outline current resources and their limitations.
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Affiliation(s)
- Marlon R Schneider
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, Munich, Germany.
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Lin C, Yin Y, Veith GM, Fisher AV, Long F, Ma L. Temporal and spatial dissection of Shh signaling in genital tubercle development. Development 2009; 136:3959-67. [PMID: 19906863 DOI: 10.1242/dev.039768] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Genital tubercle (GT) initiation and outgrowth involve coordinated morphogenesis of surface ectoderm, cloacal mesoderm and hindgut endoderm. GT development appears to mirror that of the limb. Although Shh is essential for the development of both appendages, its role in GT development is much less clear than in the limb. Here, by removing Shh at different stages during GT development in mice, we demonstrate a continuous requirement for Shh in GT initiation and subsequent androgen-independent GT growth. Moreover, we investigated the Hh responsiveness of different tissue layers by removing or activating its signal transducer Smo with tissue-specific Cre lines, and established GT mesenchyme as the primary target tissue of Shh signaling. Lastly, we showed that Shh is required for the maintenance of the GT signaling center distal urethral epithelium (dUE). By restoring Wnt-Fgf8 signaling in Shh(-/-) cloacal endoderm genetically, we revealed that Shh relays its signal partly through the dUE, but regulates Hoxa13 and Hoxd13 expression independently of dUE signaling. Altogether, we propose that Shh plays a central role in GT development by simultaneously regulating patterning of the cloacal field and supporting an outgrowth signal.
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Affiliation(s)
- Congxing Lin
- Division of Dermatology, Washington University School of Medicine, 660 S. Euclid Avenue, St Louis, MO 63110, USA
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New mouse lines for the analysis of neuronal morphology using CreER(T)/loxP-directed sparse labeling. PLoS One 2009; 4:e7859. [PMID: 19924248 PMCID: PMC2775668 DOI: 10.1371/journal.pone.0007859] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 10/20/2009] [Indexed: 12/30/2022] Open
Abstract
Background Pharmacologic control of Cre-mediated recombination using tamoxifen-dependent activation of a Cre-estrogen receptor ligand binding domain fusion protein [CreER(T)] is widely used to modify and/or visualize cells in the mouse. Methods and Findings We describe here two new mouse lines, constructed by gene targeting to the Rosa26 locus to facilitate Cre-mediated cell modification. These lines should prove particularly useful in the context of sparse labeling experiments. The R26rtTACreER line provides ubiquitous expression of CreER under transcriptional control by the tetracycline reverse transactivator (rtTA); dual control by doxycycline and tamoxifen provides an extended dynamic range of Cre-mediated recombination activity. The R26IAP line provides high efficiency Cre-mediated activation of human placental alkaline phosphatase (hPLAP), complementing the widely used, but low efficiency, Z/AP line. By crossing with mouse lines that direct cell-type specific CreER expression, the R26IAP line has been used to produce atlases of labeled cholinergic and catecholaminergic neurons in the mouse brain. The R26IAP line has also been used to visualize the full morphologies of retinal dopaminergic amacrine cells, among the largest neurons in the mammalian retina. Conclusions The two new mouse lines described here expand the repertoire of genetically engineered mice available for controlled in vivo recombination and cell labeling using the Cre-lox system.
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