title: The role of ATP binding cassette transporters in tissue defense and organ regeneration.
abstract: ATP binding cassette (ABC) transporters are ATP-dependent membrane proteins predominantly expressed in excretory organs, such as the liver, intestine, blood-brain barrier, blood-testes barrier, placenta, and kidney. Here, they play an important role in the absorption, distribution, and excretion of drugs, xenobiotics, and endogenous compounds. In addition, the ABC transporters, P-glycoprotein (P-gp/ABCB1) and breast cancer resistance protein (BCRP/ABCG2), are highly expressed in a population of primitive stem cells: the side population (SP). SP cells were originally discovered in bone marrow by their capacity to exclude rhodamine 123 and Hoechst dye 33342; however, extensive research also revealed their presence in other nonhematopoietic tissues. The expression levels of BCRP and P-gp are tightly controlled and may determine the differentiation of SP cells toward other more specialized cell types. Although their exact function in these cells is still not clear, they may protect the cells by pumping out toxicants and harmful products of oxidative stress. Transplantation studies in animals revealed that bone marrow-derived SP cells contribute to organ repopulation and tissue repair after damage, e.g., in liver and heart. The role of SP cells in regeneration of damaged kidney segments is not yet clarified. This review focuses on the role of ABC transporters in tissue defense and regeneration, with specific attention to P-gp and BCRP in organ regeneration and repair.
authors.affiliation: Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Miriam
authors.initials: M
authors.lastname: Huls
authors.forename: Frans G M
authors.initials: FG
authors.lastname: Russel
authors.forename: Rosalinde
authors.initials: R
authors.lastname: Masereeuw
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism; D018528:ATP-Binding Cassette Transporters / Q000145:classification / Q000235:genetics / Q000502:physiology*; D000818:Animals; D002545:Brain Ischemia / Q000503:physiopathology; D001943:Breast Neoplasms / Q000503:physiopathology; D005260:Female; D005786:Gene Expression Regulation; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans; D008297:Male; D009928:Organ Specificity; D004364:Pharmaceutical Preparations / Q000378:metabolism; D011247:Pregnancy; D012038:Regeneration / Q000502:physiology*; D015427:Reperfusion Injury / Q000503:physiopathology; D015262:Xenobiotics / Q000378:metabolism
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; D004364:Pharmaceutical Preparations; D015262:Xenobiotics