Differential effects of hypoxia on osteochondrogenic potential of human adipose-derived stem cells.
Human adipose tissue-derived stem cells (hATSC) have been contemplated as reparative cells for cartilage engineering. Chondrogenic differentiation of hATSC can be induced by an enriched culture medium and a three-dimensional environment. Given that bone is vascularized and cartilage is not, oxygen tension has been suggested as a regulatory factor for osteochondrogenic differentiation. Our work aimed at determining whether hypoxia affects the osteochondrogenic potential of hATSC. hATSC were cultured in chondrogenic or osteogenic medium for 28 days, in pellets or monolayers, and under 5% or 20% oxygen tension. Cell differentiation was monitored by real-time PCR (COL2A1, aggrecan, Runx2, and osteocalcin). The chondrogenic differentiation was further evaluated by Alcian blue and immunohistological staining for glycosaminoglycans (GAGs) and type II collagen, respectively. Osteogenic differentiation was also assessed by the staining of mineralized matrix (Alizarin Red) and measurement of alkaline phosphatase (ALP) activity. The expression of chondrogenic markers was upregulated when hATSC were exposed to hypoxia in chondrogenic medium. Conversely, osteocalcin expression, mineralization, and ALP activity were severely reduced under hypoxic conditions even in the presence of osteogenic medium. Our data strongly suggest that hypoxia favors the chondrogenic differentiation of hATSC as evidenced by the expression of the chondrogenic markers, whereas it could alter their osteogenic potential. Our results highlight the differential regulatory role of hypoxia on the chondrogenic and osteogenic differentiation processes of hATSC. These data could help us exploit the potential of tissue engineering and stem cells to replace or restore the function of osteoarticular tissues.
Merceron
Christophe
C
Institut National de la Santé et de la Recherche Médicale U791, Laboratoire d'ingénierie Ostéo-Articulaire et Dentaire (LIOAD), Group "Physiopathology of Skeletal Tissues and Cartilage Engineering," 44042 Nantes Cedex 1, France.
Vinatier
Claire
C
Portron
Sophie
S
Masson
Martial
M
Amiaud
Jérôme
J
Guigand
Lydie
L
Chérel
Yan
Y
Weiss
Pierre
P
Guicheux
Jérôme
J
D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism*; D053674:Aggrecans / Q000235:genetics; D000469:Alkaline Phosphatase / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002113:Calcification, Physiologic; D015687:Cell Hypoxia; D049109:Cell Proliferation; D002478:Cells, Cultured; D020219:Chondrogenesis / Q000235:genetics; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics; D005786:Gene Expression Regulation; D005819:Genetic Markers; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D015675:Osteocalcin / Q000235:genetics; D010012:Osteogenesis / Q000235:genetics; D010100:Oxygen / Q000378:metabolism*; D010641:Phenotype; D013234:Stem Cells / Q000378:metabolism*; D013997:Time Factors
D053674:Aggrecans; D015415:Biomarkers; C499177:COL2A1 protein, human; D024043:Collagen Type II; D050659:Core Binding Factor Alpha 1 Subunit; D005819:Genetic Markers; D006025:Glycosaminoglycans; C493709:RUNX2 protein, human; D015675:Osteocalcin; D000469:Alkaline Phosphatase; D010100:Oxygen