Differentiation of Mesenchymal Stem Cells under Hypoxia and Normoxia: Lipid Profiles Revealed by Time-of-Flight Secondary Ion Mass Spectrometry and Multivariate Analysis

Abstract

Mesenchymal stem cells (MSC) have the ability to self-renew and differentiate into multiple cell types valuable for clinical treatment of rheumatic pathologies. To study the chondrogenic potential of MSC and identify the conditions that recreate the native cartilage environment, we used time-of-flight secondary ion mass spectrometry (TOF-SIMS) for label-free detection of cell-type- and environmental-condition-specific molecular profiles. We observed that coculture of human MSC and chondrocytes under standard culture conditions leads to improved extracellular matrix (ECM) deposition. In marked contrast, this effect was lost under low oxygen tension. This improved extracellular matrix deposition was associated with a significant decrease in lipids and in particular cholesterol under low oxygen tension as revealed by TOF-SIMS coupled to principal component analysis and discriminant analysis. We furthermore demonstrate that the higher cholesterol levels under normoxia might regulate fibroblast growth factor 1 (FGF-1) gene expression which was previously implemented in increased ECM production in the cocultures. In conclusion, our study shows an unexpected role of lipids as orchestrators of chondrogenesis in response to oxygen tension which is, at least in part, mediated through FGF-1.

Molecular Validation of Chondrogenic Differentiation and Hypoxia Responsiveness of Platelet-Lysate Expanded Adipose Tissue–Derived Human Mesenchymal Stromal Cells

“…As a consequence of continuous hypoxia under chondrogenic induction, stem cells start to produce hyaline cartilage that is resistant to hypertrophic differentiation, whereas incubation under normoxia conditions results in hypertrophic cartilage that resembles epiphyseal cartilage. 26,41 Our data indicate that under chondrogenic induction AMSCs develop a chondrocyte-like phenotype, but may have a propensity to exhibit a hypertrophic response unless exposed to a hypoxic environment. Furthermore, our study suggests that molecular pathways utilized by AMSCs undergoing chondrogenic differentiation are different from those used by primary human chondrocytes.…”

The cross-sectional and longitudinal effect of hyperlipidemia on knee osteoarthritis: Results from the Dongfeng-Tongji cohort in China

“…Other factors such as lipid disorders, which may interfere with joint metabolism, have also garnered considerable attention. A few studies have found associations between elevated blood lipids and disturbed differentiation or metabolism of chondrocyte 15 – 17 . The prevalence of hyperlipidemia have increased dramatically in China 18 , however, the potential effects of hyperlipidemia on KOA have not been adequately evaluated among Chinese.…”

Protective effects of mitochondria‐targeted antioxidants and statins on cholesterolinduced osteoarthritis

“…Chondrocytes have naturally high levels of cholesterol in their cell membranes (6) and produce their own cholesterol, expressing all the necessary proteins for cholesterol biosynthesis, such as 3‐hydroxy‐3‐methylglutaryl‐coenzyme A synthase 1, acetyl‐coenzyme A acetyltransferase 1, or low‐density lipoprotein receptor (7). There is evidence that indicates that cholesterol has a regulatory role in chondrogenic differentiation and that its expression is particularly sensitive to hypoxic conditions (8). Aberrant regulation of cholesterol homeostasis is a characteristic feature of OA development, with accumulation of cholesterol and fatty acids found particularly within the superficial zone of the cartilage (9).…”