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Lyu QR, Fu K. Tissue-specific Cre driver mice to study vascular diseases. Vascul Pharmacol 2023; 153:107241. [PMID: 37923099 DOI: 10.1016/j.vph.2023.107241] [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: 08/02/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
Vascular diseases, including atherosclerosis and abdominal aneurysms, are the primary cause of mortality and morbidity among the elderly worldwide. The life quality of patients is significantly compromised due to inadequate therapeutic approaches and limited drug targets. To expand our comprehension of vascular diseases, gene knockout (KO) mice, especially conditional knockout (cKO) mice, are widely used for investigating gene function and mechanisms of action. The Cre-loxP system is the most common method for generating cKO mice. Numerous Cre driver mice have been established to study the main cell types that compose blood vessels, including endothelial cells, smooth muscle cells, and fibroblasts. Here, we first discuss the characteristics of each layer of the arterial wall. Next, we provide an overview of the representative Cre driver mice utilized for each of the major cell types in the vessel wall and their most recent applications in vascular biology. We then go over Cre toxicity and discuss the practical methods for minimizing Cre interference in experimental outcomes. Finally, we look into the future of tissue-specific Cre drivers by introducing the revolutionary single-cell RNA sequencing and dual recombinase system.
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Affiliation(s)
- Qing Rex Lyu
- Medical Research Center, Chongqing General Hospital, Chongqing 401147, China; Chongqing Academy of Medical Sciences, Chongqing 401147, China.
| | - Kailong Fu
- Department of Traditional Chinese Medicine, Fujian Medical University Union Hospital, Fuzhou 350001, China.
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2
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Zhao Y, Zhao G, Chang Z, Zhu T, Zhao Y, Lu H, Xue C, Saunders TL, Guo Y, Chang L, Chen YE, Zhang J. Generating endogenous Myh11-driven Cre mice for sex-independent gene deletion in smooth muscle cells. JCI Insight 2023; 8:e171661. [PMID: 37289544 PMCID: PMC10443793 DOI: 10.1172/jci.insight.171661] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/05/2023] [Indexed: 06/10/2023] Open
Abstract
Specific and efficient smooth muscle cell-targeted (SMC-targeted) gene deletion is typically achieved by pairing SMMHC-CreERT2-Tg mice with mice carrying the loxP-flanked gene. However, the transgene, CreERT2, is not controlled by the endogenous Myh11 gene promoter, and the codon-modified iCreERT2 exhibits significant tamoxifen-independent leakage. Furthermore, because the Cre-bearing bacterial artificial chromosome (BAC) is inserted onto the Y chromosome, the SMMHC-CreERT2-Tg mice strain can only exhibit gene deletions in male mice. Additionally, there is a lack of Myh11-driven constitutive Cre mice when tamoxifen usage is a concern. We used CRISPR/Cas9-mediated homologous recombination between a donor vector carrying the CreNLSP2A or CreERT2-P2A sequence and homologous arm surrounding the translation start site of the Myh11 gene to generate Cre-knockin mice. The P2A sequence enables the simultaneous translation of Cre and endogenous proteins. Using reporter mice, we assessed Cre-mediated recombination efficiency, specificity, tamoxifen-dependent controllability, and functionality in both sexes. Both constitutive (Myh11-CreNLSP2A) and inducible (Myh11-CreERT2-P2A) Cre mice demonstrated efficient, SMC-specific, sex-independent Cre recombinase activity without confounding endogenous gene expression. Combined with recently generated BAC transgenic Myh11-CreERT2-RAD mice and the Itga8-CreERT2 mouse models, our models will help expand the research toolbox, facilitating unbiased and comprehensive research in SMCs and SMC-dependent cardiovascular diseases.
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Affiliation(s)
- Yang Zhao
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
- Department of Pharmacology and
| | - Guizhen Zhao
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Ziyi Chang
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Tianqing Zhu
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Ying Zhao
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Haocheng Lu
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Chao Xue
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Thomas L. Saunders
- Transgenic Animal Model Core, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Yanhong Guo
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Lin Chang
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Y. Eugene Chen
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Jifeng Zhang
- Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, Ann Arbor, Michigan, USA
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3
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Numaga-Tomita T, Shimauchi T, Kato Y, Nishiyama K, Nishimura A, Sakata K, Inada H, Kita S, Iwamoto T, Nabekura J, Birnbaumer L, Mori Y, Nishida M. Inhibition of transient receptor potential cation channel 6 promotes capillary arterialization during post-ischaemic blood flow recovery. Br J Pharmacol 2023; 180:94-110. [PMID: 36068079 PMCID: PMC10092707 DOI: 10.1111/bph.15942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE Capillary arterialization, characterized by the coverage of pre-existing or nascent capillary vessels with vascular smooth muscle cells (VSMCs), is critical for the development of collateral arterioles to improve post-ischaemic blood flow. We previously demonstrated that the inhibition of transient receptor potential 6 subfamily C, member 6 (TRPC6) channels facilitate contractile differentiation of VSMCs under ischaemic stress. We here investigated whether TRPC6 inhibition promotes post-ischaemic blood flow recovery through capillary arterialization in vivo. EXPERIMENTAL APPROACH Mice were subjected to hindlimb ischaemia by ligating left femoral artery. The recovery rate of peripheral blood flow was calculated by the ratio of ischaemic left leg to non-ischaemic right one. The number and diameter of blood vessels were analysed by immunohistochemistry. Expression and phosphorylation levels of TRPC6 proteins were determined by western blotting and immunohistochemistry. KEY RESULTS Although the post-ischaemic blood flow recovery is reportedly dependent on endothelium-dependent relaxing factors, systemic TRPC6 deletion significantly promoted blood flow recovery under the condition that nitric oxide or prostacyclin production were inhibited, accompanying capillary arterialization. Cilostazol, a clinically approved drug for peripheral arterial disease, facilitates blood flow recovery by inactivating TRPC6 via phosphorylation at Thr69 in VSMCs. Furthermore, inhibition of TRPC6 channel activity by pyrazole-2 (Pyr2; BTP2; YM-58483) promoted post-ischaemic blood flow recovery in Apolipoprotein E-knockout mice. CONCLUSION AND IMPLICATIONS Suppression of TRPC6 channel activity in VSMCs could be a new strategy for the improvement of post-ischaemic peripheral blood circulation.
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Affiliation(s)
- Takuro Numaga-Tomita
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan.,Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Aichi, Japan.,SOKENDAI (School of Life Science, The Graduate University for Advanced Studies), Aichi, Japan.,Shinshu University School of Medicine, Nagano, Japan
| | - Tsukasa Shimauchi
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan.,Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Aichi, Japan.,Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.,Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuri Kato
- Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazuhiro Nishiyama
- Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Akiyuki Nishimura
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan.,Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Aichi, Japan.,SOKENDAI (School of Life Science, The Graduate University for Advanced Studies), Aichi, Japan
| | - Kosuke Sakata
- Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroyuki Inada
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan
| | - Satomi Kita
- Faculty of Medicine, Fukuoka University, Fukuoka, Japan.,Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan
| | | | - Junichi Nabekura
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan
| | - Lutz Birnbaumer
- NIEHS, NIH, Research Triangle Park, North Carolina, USA.,Institute for Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires, Argentina
| | - Yasuo Mori
- Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Motohiro Nishida
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan.,Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Aichi, Japan.,SOKENDAI (School of Life Science, The Graduate University for Advanced Studies), Aichi, Japan.,Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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4
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Chakraborty R, Saddouk FZ, Carrao AC, Krause DS, Greif DM, Martin KA. Promoters to Study Vascular Smooth Muscle. Arterioscler Thromb Vasc Biol 2020; 39:603-612. [PMID: 30727757 DOI: 10.1161/atvbaha.119.312449] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Smooth muscle cells (SMCs) are a critical component of blood vessel walls that provide structural support, regulate vascular tone, and allow for vascular remodeling. These cells also exhibit a remarkable plasticity that contributes to vascular growth and repair but also to cardiovascular pathologies, including atherosclerosis, intimal hyperplasia and restenosis, aneurysm, and transplant vasculopathy. Mouse models have been an important tool for the study of SMC functions. The development of smooth muscle-expressing Cre-driver lines has allowed for exciting discoveries, including recent advances revealing the diversity of phenotypes derived from mature SMC transdifferentiation in vivo using inducible CreER T2 lines. We review SMC-targeting Cre lines driven by the Myh11, Tagln, and Acta2 promoters, including important technical considerations associated with these models. Limitations that can complicate study of the vasculature include expression in visceral SMCs leading to confounding phenotypes, and expression in multiple nonsmooth muscle cell types, such as Acta2-Cre expression in myofibroblasts. Notably, the frequently employed Tagln/ SM22α- Cre driver expresses in the embryonic heart but can also confer expression in nonmuscular cells including perivascular adipocytes and their precursors, myeloid cells, and platelets, with important implications for interpretation of cardiovascular phenotypes. With new Cre-driver lines under development and the increasing use of fate mapping methods, we are entering an exciting new era in SMC research.
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Affiliation(s)
- Raja Chakraborty
- From the Department of Medicine, Section of Cardiovascular Medicine (R.C., F.Z.S., A.C.C., D.M.G., K.A.M.)
| | - Fatima Zahra Saddouk
- From the Department of Medicine, Section of Cardiovascular Medicine (R.C., F.Z.S., A.C.C., D.M.G., K.A.M.).,Department of Genetics (F.Z.S., D.M.G.)
| | - Ana Catarina Carrao
- From the Department of Medicine, Section of Cardiovascular Medicine (R.C., F.Z.S., A.C.C., D.M.G., K.A.M.)
| | - Diane S Krause
- Departments of Laboratory Medicine, Cell Biology, and Pathology (D.S.K.)
| | - Daniel M Greif
- From the Department of Medicine, Section of Cardiovascular Medicine (R.C., F.Z.S., A.C.C., D.M.G., K.A.M.).,Department of Genetics (F.Z.S., D.M.G.)
| | - Kathleen A Martin
- From the Department of Medicine, Section of Cardiovascular Medicine (R.C., F.Z.S., A.C.C., D.M.G., K.A.M.).,Department of Pharmacology (K.A.M.), Yale University School of Medicine, New Haven, CT
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Hao T, Liu YH, Li YY, Lu Y, Xu HY. A Transcriptomic Analysis of Physiological Significance of Hypoxia-inducible Factor-1α in Myogenesis and Carbohydrate Metabolism of Genioglossus in Mice. Chin Med J (Engl) 2017. [PMID: 28639573 PMCID: PMC5494921 DOI: 10.4103/0366-6999.208235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Background: Chronic intermittent hypoxia is the most remarkable feature of obstructive sleep apnea/hypopnea syndrome and it can induce the change of hypoxia-inducible factor-1α (HIF-1α) expression and contractile properties in the genioglossus. To clarify the role of HIF-1α in contractile properties of the genioglossus, this study generated and compared high-throughput RNA-sequencing data from genioglossus between HIF-1α conditional knockout (KO) mice and littermate wild-type (WT) mice. Methods: KO mice were generated with cre-loxP strategy. Gene expression profile analysis was performed using gene enrichment analysis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of differently expressed messenger RNAs were performed to identify the related pathways and biological functions. Six differentially expressed genes (DEGs) were validated by qualitative reverse transcription polymerase chain reaction. Results: A total of 142 (77 upregulated and 65 downregulated) transcripts were found to exhibit statistically significant difference between the HIF-1α-KO and WT mice. GO and KEGG analyses indicated that DEGs included genes involved in “skeletal muscle cell differentiation,” “muscle organ development,” “glucose metabolic process,” “glycogen biosynthetic and metabolic process,” etc. Conclusion: This study might provide evidence that HIF-1α affects the expression of multiple genes involved in the myogenesis, muscle development, and carbohydrate metabolism through transcriptome analysis in conditional HIF-1α-KO mice.
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Affiliation(s)
- Tong Hao
- Department of Orthodontics, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, China
| | - Yue-Hua Liu
- Department of Orthodontics, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072; Department of Orthodontics, Shanghai Stomatological Hospital, Shanghai 200001, China
| | - Yuan-Yuan Li
- Department of Orthodontics, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, China
| | - Yun Lu
- Department of Orthodontics, Shanghai Stomatological Hospital, Shanghai 200001, China
| | - Hong-Yi Xu
- Department of Orthodontics, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, China
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6
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Nishii K, Seki A, Kumai M, Morimoto S, Miwa T, Hagiwara N, Shibata Y, Kobayashi Y. Connexin45 contributes to global cardiovascular development by establishing myocardial impulse propagation. Mech Dev 2016; 140:41-52. [DOI: 10.1016/j.mod.2016.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 02/19/2016] [Accepted: 02/20/2016] [Indexed: 11/15/2022]
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7
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Maruyama T, Hatakeyama S, Miwa T, Nishimori K. Human Smooth Muscle α-Actin Promoter Drives Cre Recombinase Expression in the Cranial Suture in Addition to Smooth Muscle Cell. Biosci Biotechnol Biochem 2014; 71:1103-6. [PMID: 17420573 DOI: 10.1271/bbb.70043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Tissue-specific gene deletion by the Cre-loxp system is a powerful tool to investigate the roles of specific genes. To determine the specificity and efficiency of the Cre-mediated recombination under the control of the human smooth muscle alpha-actin promoter, we mated SMalphaA-Cre mice and R26R reporter mice. Cre-mediated recombination was observed in visceral and vascular smooth muscle cells. Partial recombination was also found in heart and musculoskeletal connective tissues. Highly efficient recombination was found in cranial sutures. Hence, we propose that SMalphaA-Cre mice are good tool for conditionally deleting gene function in the cranial suture in addition to smooth muscle cells.
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Affiliation(s)
- Takamitsu Maruyama
- Department of Molecular Biology, Graduate School of Agriculture, Tohoku University, Sendai, Japan
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8
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Abstract
Stromal-epithelial interactions mediated by paracrine signaling mechanisms dictate prostate development and progression of prostate cancer. The regulatory role of androgens in both the prostate stromal and epithelial compartments set the prostate apart from many other organs and tissues with regard to gene targeting. The identification of androgen-dependent prostate epithelial promoters has allowed successful gene targeting to the prostate epithelial compartment. Currently, there are no transgenic mouse models available to specifically alter gene expression within the prostate stromal compartment. As a primary metastatic site for prostate cancer is bone, the functional dissection of the bone stromal compartment is important for understanding stromal-epithelial interactions associated with metastatic tumor growth. Use of currently available methodologies for the expression or deletion of gene expression in recent research studies has advanced our understanding of the stroma. However, the complexity of stromal heterogeneity within the prostate remains a challenge to obtaining compartment or cell-lineage-specific in vivo models necessary for furthering our understanding of prostatic developmental, benign, tumorigenic, and metastatic growth.
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Affiliation(s)
- Roger S Jackson
- Department of Urologic Surgery, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232-2765, USA
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9
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Seidi A, Mie M, Kobatake E. Novel recombination system using Cre recombinase alpha complementation. Biotechnol Lett 2007; 29:1315-22. [PMID: 17530179 DOI: 10.1007/s10529-007-9406-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 04/23/2007] [Accepted: 04/24/2007] [Indexed: 10/23/2022]
Abstract
A major limitation for the use of Cre recombinase is its toxicity and a lack of temporal control over its activity. We have developed a new recombination system using Cre recombinase alpha-complementation. Cre recombinase was divided and one fragment (beta) was introduced into cells between two loxP sites with a CMV promoter in the upstream. The gene of interest (EGFP) was positioned just downstream of this construct. Cre recombinase activity was recovered by adding the other part of the molecule (alpha) to cells as a protein fragment, as evidenced by the expression of EGFP under the control of the CMV promoter. The activity of fragmented cre reached 68% of that of the wild type enzyme at 1 microM alpha-protein.
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Affiliation(s)
- Azadeh Seidi
- Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan
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10
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Wamhoff BR, Sinha S, Owens GK. Conditional mouse models to study developmental and pathophysiological gene function in muscle. Handb Exp Pharmacol 2007:441-68. [PMID: 17203666 DOI: 10.1007/978-3-540-35109-2_18] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This chapter will review conditional mouse model systems that have been developed to study gene function in skeletal, cardiac, and vascular smooth muscle cells in vivo with an emphasis on the utility of these models for investigating developmental and pathophysiological gene function in muscle. In general, these systems have utilized muscle-specific/selective promoter-enhancers in conjunction with site-specific DNA recombinases, e.g., Cre-loxP, and fusion proteins with these recombinases that confer temporal control, such as tamoxifen-inducible CreER systems. A major focus of this chapter will be to discuss unique challenges of studying Cre-mediated mutagenesis/gene targeting in these muscle types during development and in the adult animal, some of which are inherent of the muscle cell type being studied. For example, unlike cardiac and skeletal muscle cells, the vascular SMC is extremely plastic and able to undergo rapid phenotypic modulation to various environmental cues in vivo. Thus, employing SMC marker gene promoter enhancers for conditional gene targeting in SMCs must take into account the possibility and/or certainty that the particular SMC promoter enhancers used may or may not be transcriptionally active in SMCs of a vessel wall under normal and some pathophysiological conditions. Moreover, individual floxed loci within the same muscle cell type and tissue have different degrees of sensitivity to Cre, most likely dependent on the chromatin state of that particular gene, i.e., closed/condensed state or open/active state. Thus, Cre recombination may be ineffective for specific floxed gene DNA. Lastly, rigorous efforts must be made to confirm the degree of recombination in a tissue, taking into full account the multicellularity of the tissue, to understand the extent of the physiological effect in that organ.
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Affiliation(s)
- B R Wamhoff
- Molecular Physiology and Biological Physics, The Robert M. Berne Cardiovascular Research Center, The University of Virginia, 415 Lane Road, Medical Research Building 5, Room 1226, P.O. Box 801394, Charlottesville VA 22908, USA
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11
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Heidt AB, Black BL. Transgenic mice that express Cre recombinase under control of a skeletal muscle-specific promoter from mef2c. Genesis 2005; 42:28-32. [PMID: 15828002 DOI: 10.1002/gene.20123] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Genes expressed in skeletal muscle are often required in other tissues. This is particularly the case for cardiac and smooth muscle, both contractile tissues that share numerous characteristics with skeletal muscle, such that targeted inactivation can lead to embryonic lethality prior to a requirement for gene function in skeletal muscle. Thus, it is essential that conditional inactivation approaches are developed to disrupt genes specifically in skeletal muscle. In this report, we describe a transgenic mouse that expresses Cre recombinase under the control of a skeletal muscle-specific promoter from the mef2c gene. Cre expression in this transgenic line is completely restricted to skeletal muscle from early in development and is present in all skeletal muscles, including those of epaxial and hypaxial origins and in fast and slow fibers. This early skeletal muscle-specific Cre line will be a useful tool to define the function of genes specifically in skeletal muscle.
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Affiliation(s)
- Analeah B Heidt
- Cardiovascular Research Institute, University of California, San Francisco, California 94143-0130, USA
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12
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Heine HL, Leong HS, Rossi FMV, McManus BM, Podor TJ. Strategies of Conditional Gene Expression in Myocardium. MOLECULAR CARDIOLOGY 2005; 112:109-54. [PMID: 16010014 DOI: 10.1007/978-1-59259-879-3_8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The use of specialized reporter genes to monitor real-time, tissue-specific transgene expression in animal models offers an opportunity to circumvent current limitations associated with the establishment of transgenic mouse models. The Cre-loxP and the tetracycline (Tet)-inducible systems are useful methods of conditional gene expression that allow spatial (cell-type-specific) and temporal (inducer-dependent) control. Most often, the alpha-myosin heavy chain (alpha-MHC) promoter is used in these inducible systems to restrict expression of reporter genes and transgenes to the myocardium. An overview of each inducible system is described, along with suggested reporter genes for real-time, noninvasive imaging in the myocardium. Effective gene delivery of the inducible gene expression system is carried out by lentiviral vectors, which offer high transduction efficiency, long-term transgene expression, and low immunogenicity. This chapter outlines the packaging of myocardium-specific inducible expression systems into lentiviral vectors, in which a transgene and a reporter gene are transduced into cardiomyocytes. In doing so, transgene and reporter expression can be monitored/tracked with bioluminescence imaging (BLI) and positron emission tomography (PET).
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Affiliation(s)
- Heather L Heine
- The James Hogg iCAPTURE Center for Cardiovascular and Pulmonary Research/MRL, University of British Columbia, St. Paul's Hospital, Vancouver, Canada
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13
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Nishii K, Kumai M, Egashira K, Miwa T, Hashizume K, Miyano Y, Shibata Y. Mice lacking connexin45 conditionally in cardiac myocytes display embryonic lethality similar to that of germline knockout mice without endocardial cushion defect. ACTA ACUST UNITED AC 2004; 10:365-9. [PMID: 14681043 DOI: 10.1080/cac.10.4-6.365.369] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The gap junction protein connexin45-deficient (Cx45-KO) mice die shortly after the hearts begin to beat. In addition to the heart defect, they also show defective vascular development which may be closely related with the cardiac phenotype. Therefore, we created mice whose floxed-Cx45 locus could be removed conditionally. We utilized cardiac alpha-actin-Cre transgenic mice to investigate the specific cardiac muscular function of Cx45 in vivo. The resultant conditional mutants were lethal, showing conduction block similar to that of the Cx45-KO mice. Unlike Cx45-KO, development of the endocardial cushion was not disrupted in the conditional mutants. X-gal staining was detected in the embryonic cardiac myocytes as a hallmark of Cre-loxP mediated floxed-Cx45 deletion. These results reconfirm the requirement of Cx45 for developing cardiac myocytes. These also indicate that establishing the first contractions is a crucial task for the early hearts.
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Affiliation(s)
- Kiyomasa Nishii
- Department of Developmental Molecular Anatomy, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
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14
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Affiliation(s)
- Elvin L Garcia
- Graduate Program in Genetics, State University of New York at Stony Brook, Stony Brook, NY 11794, USA
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