[Frontiers in Bioscience E3, 1229-1240, June 1, 2011]

[Frontiers in Bioscience E3, 1229-1240, June 1, 2011]

Na⁺, K⁺-ATPase genes are down-regulated during adipose stem cell differentiation

Elisa Acosta¹, Julio Avila¹, Ali Mobasheri², Pablo Martin-Vasallo¹

1Laboratorio de Biologia del Desarrollo, Departamento de Bioquimica y Biologia Molecular, Universidad de La Laguna, Av. Astrofisico Sanchez s/n. 38201 La Laguna, Tenerife, Spain, ²Division of Veterinary Medicine, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire, LE12 5RD, United Kingdom

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and Methods: 3.1. Isolation and culture of rat adipose mesenchymal stem cells; 3.2. Differentiation of adipose derived mesenchymal stem cel; 3.3. Reverse transcription-linked polymerase chain reaction, real-time quantitative RT-PCR (qRT-PCR); 3.4. Antibodies; 3.5. Immunofluorescence
4. Results: 4.1. Control of ASC as stem cells and adipogenic and chondrogenic differentiation of ASC; 4.2. Expression levels; 4.3. Cellular localization; 4.4. Lack of IGF-I effects on Na+, K+-ATPase expression in ASCs; 4.5. Na+, K+-ATPase expression in chondrocytes differentiated from ASCs
5. Discussion: 5.1. Kinetic differences of Na+, K+-ATPase isozymes in ASCs; 5.2. Comments on other specific roles of the beta subunit; 5.3. The lack of IGF-I effects on Na+, K+-ATPase in ASCs
6. Acknowledgements
7. References

1. ABSTRACT

The expression of Na⁺, K⁺-ATPase alpha and beta subunits isoforms, FXYD2 and FXYD7 were studied in rat adipose stem cell (ASC) by qRT-PCR and immunofluorescence. ASCs were able to differentiate to chondrocytes or adipocytes. All studied genes were expressed in freshly isolated ASCs and in all passages checked. Immunostaining for alpha1 isoform was found in plasma membrane and nuclear envelope, alpha2 signal was lower and alpha3 staining was variable among cells. Beta isoforms signal was abundant and displayed an isoform-specific picture. Staining for FXYD7 was homogeneous in plasma membrane and cytosol. Chondrocytes differenciated from ASC showed identical Na⁺, K⁺-ATPase subunits isoforms expression patterns to chondrocytes in cartilage. The expression pattern of Na⁺, K⁺-ATPase genes in ASCs exhibits a unique phenotypic signature that implies functional differences in Na⁺and K⁺ transport rates. Furthermore, this phenotypic signature may also be used as a complementary marker for studies of mesenchymal stem cell differentiation. We propose a possible 'moonlighting' role of Na⁺, K⁺-ATPase beta isoforms that could be essential for the study of mesenchymal stem cell function and differentiation.