dorsomorphin and Hypertrophy

Autologous chondrocyte implantation is a cell-based treatment to repair articular cartilage defects, relying on the availability of expanded (de-differentiated) chondrocytes. Unfortunately, the expansion process causes several phenotypical changes, requiring re-establishment of the native chondrogenic phenotype to sustain proper repair. Among other proteins, transforming growth factor-β (TGFβ) is known to influence the chondrogenic re-differentiation of human articular chondrocytes (HACs) and their matrix deposition. Thus we investigated the effects of TGFβ-depletion during the expansion phase.. HACs were isolated from articular cartilage and expanded in the canonical serum-supplemented medium [fetal calf serum (FCS)] or in a chemically-defined (CD) medium, with or without anti-TGFβ antibody administration. The re-differentiation potential of the cells was assessed by pellet cultures, gene expression analysis and histology.. Cell proliferation proceeded more rapidly in CD-medium than in FCS-medium; it was not affected by the use of anti-TGFβ antibody but was further increased by addition of exogenous TGFβ1, via increased p-Smad1/5/8. Conversely, in FCS-medium, addition of anti-TGFβ antibody decreased both proliferation and p-Smad1/5/8 level. Challenging either FCS- or CD-medium with anti-TGFβ antibody during expansion enhanced chondrogenesis in the subsequent pellet cultures. Moreover, TGFβ-depletion during expansion in CD-medium inhibited mRNA expression of hypertrophic markers, collagen type-X (COL10) and matrix metalloproteinase-13 (MMP-13). Interestingly, the TGFβ1 level detected by enzyme-linked immunosorbent sandwich assay (ELISA) during cell expansion was correlated with COL10 mRNA expression after re-differentiation.. TGFβ-depletion during expansion improves the re-differentiation capacity of chondrocytes and inhibits hypertrophy. These results indicate the importance of the expansion medium composition to improve chondrogenic re-differentiation and to inhibit hypertrophy.

Topics: Antibodies, Blocking; Benzamides; Biomarkers; Cartilage, Articular; Cell Culture Techniques; Cell Differentiation; Cell Enlargement; Cell Proliferation; Cells, Cultured; Chondrocytes; Culture Media; Culture Media, Serum-Free; Humans; Hypertrophy; Knee Injuries; Osteoarthritis, Knee; Pyrazoles; Pyrimidines; Smad Proteins; Transforming Growth Factor beta

Increased adrenergic drive is a major factor influencing the development of pathological cardiac hypertrophy, a stage which precedes overt heart failure. We examined the effect of resveratrol, a polyphenol (found predominantly in grapes), in preventing norepinephrine induced hypertrophy of adult cardiomyocyte, and the role of nitric oxide (NO) and adenosine monophosphate kinase (AMPK) in the effects of resveratrol. Cardiomyocytes isolated from adult rats were pretreated, or not, with resveratrol and then exposed to norepinephrine for 24h. In other experiments cardiomyocytes were also treated with different pharmacological inhibitors of NO synthase, AMPK and sirtuin for elucidating the signaling pathways underlying the effect of resveratrol. In order to validate the role of these signaling molecules in the in vivo settings, we also examined hearts from resveratrol treated spontaneously hypertensive rats (SHR), a genetic model of essential hypertension. Cardiomyocyte hypertrophy was determined by morphometry and (3)H-phenylalanine incorporation assay. NO levels and AMPK activity were measured using a specific assay kit and western blot analysis respectively. In vitro, resveratrol prevented the norepinephrine-induced increase in cardiomyocytes size and protein synthesis. Pharmacological inhibition of NO-AMPK signaling abolished the anti-hypertrophic action of resveratrol. Consistent with the in vitro findings, the anti-hypertrophic effect of resveratrol in the SHR model was associated with increases in NO and AMPK activity. This study demonstrates that NO-AMPK signaling is linked to the anti-hypertrophic effect of resveratrol in adult cardiomyocytes in vitro, and in the SHR model in vivo.

Topics: Adenylate Kinase; Animals; Cell Size; Hypertrophy; Male; Myocytes, Cardiac; NG-Nitroarginine Methyl Ester; Niacinamide; Nitric Oxide; Norepinephrine; Protein Biosynthesis; Pyrazoles; Pyrimidines; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Resveratrol; S-Nitroso-N-Acetylpenicillamine; Signal Transduction; Stilbenes