title: Increased differentiation capacity of bone marrow-derived mesenchymal stem cells in aquaporin-5 deficiency.
abstract: Mesenchymal stem cells (MSCs) are adult stem cells with a self-renewal and multipotent capability and express extensively in multitudinous tissues. We found that water channel aquaporin-5 (AQP5) is expressed in bone marrow-derived MSCs (BMMSCs) in the plasma membrane pattern. BMMSCs from AQP5(-/-) mice showed significantly lower plasma membrane water permeability than those from AQP5(+/+) mice. In characterizing the cultured BMMSCs from AQP5(-/-) and AQP5(+/+) mice, we found no obvious differences in morphology and proliferation between the 2 genotypes. However, the multiple differentiation capacity was significantly higher in AQP5(-/-) than AQP5(+/+) BMMSCs as revealed by representative staining by Oil Red O (adipogenesis); Alizarin Red S and alkaline phosphatase (ALP; osteogenesis); and type II collagen and Safranin O (chondrogenesis) after directional induction. Relative mRNA expression levels of 3 lineage differentiation markers, including PPARγ2, C/EBPα, adipsin, collagen 1a, osteopontin, ALP, collagen 11a, collagen 2a, and aggrecan, were significantly higher in AQP5(-/-) -differentiating BMMSCs, supporting an increased differentiation capacity of AQP5(-/-) BMMSCs. Furthermore, a bone-healing process was accelerated in AQP5(-/-) mice in a drill-hole injury model. Mechanistic studies indicated a significantly lower apoptosis rate in AQP5(-/-) than AQP5(+/+) BMMSCs. Apoptosis inhibitor Z-VAD-FMK increased the differentiation capacity to a greater extent in AQP5(+/+) than AQP5(-/-) BMMSCs. We conclude that AQP5-mediated high plasma membrane water permeability enhances the apoptosis rate of differentiating BMMSCs, thus decreasing their differentiation capacity. These data implicate AQP5 as a novel determinant of differentiation of BMMSCs and therefore a new molecular target for regulating differentiation of BMMSCs during tissue repair and regeneration.
authors.affiliation: Membrane Channel Research Laboratory, Northeast Normal University, Changchun, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Yi
authors.forename: Muhammad
authors.initials: M
authors.lastname: Khan
authors.forename: Hongwen
authors.initials: H
authors.lastname: Gao
authors.forename: Feng
authors.initials: F
authors.lastname: Hao
authors.forename: Meiyan
authors.initials: M
authors.lastname: Sun
authors.forename: Lili
authors.initials: L
authors.lastname: Zhong
authors.forename: Changzheng
authors.initials: C
authors.lastname: Lu
authors.forename: Xuechao
authors.initials: X
authors.lastname: Feng
authors.forename: Tonghui
authors.initials: T
authors.lastname: Ma
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D000880:Anthraquinones; D017209:Apoptosis; D051402:Aquaporin 5 / Q000235:genetics / Q000378:metabolism*; D001853:Bone Marrow / Q000378:metabolism*; D001861:Bone Regeneration; D002452:Cell Count; D002454:Cell Differentiation; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D002463:Cell Membrane Permeability; D048430:Cell Shape; D002478:Cells, Cultured; D020219:Chondrogenesis; D024043:Collagen Type II / Q000378:metabolism; D005269:Femur / Q000166:cytology / Q000293:injuries / Q000378:metabolism; D005838:Genotype; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D010012:Osteogenesis; D013194:Staining and Labeling; D014867:Water / Q000378:metabolism
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D000880:Anthraquinones; C496038:Aqp5 protein, mouse; D051402:Aquaporin 5; D024043:Collagen Type II; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D014867:Water; C004468:Alizarin Red S; D000469:Alkaline Phosphatase