Beschreibung:
Multipotent mesenchymal stromal cells (MSC) have emerged as therapeutic tools for awide range of pathological conditions. Yet, the still existing deficits regarding MSCphenotype characterization and the resulting heterogeneity of MSC used in differentpreclinical and clinical studies hamper the translational success. In search for novelMSC characterization approaches to complement the traditional trilineagedifferentiation and immunophenotyping assays reliably across species and cultureconditions, this study explored the applicability of lipid phenotyping for MSCcharacterization and discrimination. Human peripheral blood mononuclear cells(PBMC), human fibroblasts, and human and equine adipose-derived MSC were usedto compare different mesodermal cell types and MSC from different species. For MSC,cells cultured in different conditions, including medium supplementation with either fetalbovine serum or platelet lysate as well as culture on collagen-coated dishes, wereadditionally investigated. After cell harvest, lipids were extracted by chloroform/methanol according to Bligh and Dyer. The lipid profiles were analysed by anuntargeted approach using liquid chromatography coupled to mass spectrometry (LCMS)with a reversed phase column and an ion trap mass spectrometer. In all samples,phospholipids and sphingomyelins were found, while other lipids were not detected withthe current approach. The phospholipids included different species of phosphatidylcholine(PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidylserine (PS)in all cell types, whereas phosphatidylglycerol (PG) species were only present in MSC.MSC from both species showed a higher phospholipid species diversity than PBMC andfibroblasts. Few differences were found between MSC from different culture conditions,except that human MSC cultured with platelet lysate exhibited a unique phenotype in thatthey exclusively featured PE O-40:4, PG 38:6 and PG 40:6. In search for specific andinclusive candidate MSC lipid markers, we identified PE O-36:3 and PG 40:7 as potentiallysuitable markers across culture conditions, at which PE O-36:3 might even be used acrossspecies. On that basis, phospholipid phenotyping is a highly promising approach for MSCcharacterization, which might condone some heterogeneity within the MSC while stillachieving a clear discrimination even from fibroblasts. Particularly the presence or absenceof PG might emerge as a decisive criterion for future MSC characterization.