Characterizing human mesenchymal stromal cells' immune-modulatory potency using targeted lipidomic profiling of sphingolipids.

Cell therapies are expected to increase over the next decade owing to increasing demand for clinical applications. Mesenchymal stromal cells (MSCs) have been explored to treat a number of diseases, with some successes in early clinical trials. Despite early successes, poor MSC characterization results in lessened therapeutic capacity once in vivo. Here, we characterized MSCs derived from bone marrow (BM), adipose tissue and umbilical cord tissue for sphingolipids (SLs), a class of bioactive lipids, using liquid chromatography/tandem mass spectrometry. We found that ceramide levels differed based on the donor's sex in BM-MSCs. We detected fatty acyl chain variants in MSCs from all three sources. Linear discriminant analysis revealed that MSCs separated based on tissue source. Principal component analysis showed that interferon-γ-primed and unstimulated MSCs separated according to their SL signature. Lastly, we detected higher ceramide levels in low indoleamine 2,3-dioxygenase MSCs, indicating that sphingomyelinase or ceramidase enzymatic activity may be involved in their immune potency.

Processing-Structure-Property Relations for Radiation Tolerance of Relaxor-Ferroelectric Thin Films.

This work investigates the role of microstructure on the radiation tolerance of relaxor-ferroelectric, lead magnesium niobate-lead titanate, thin films for piezoelectric microelectromechanical system (MEMS) applications. Thin films comprised of 0.7Pb[Mg1/3Nb2/3]O3-0.3PbTiO3 were fabricated via chemical solution deposition on platinized silicon wafers. Processing parameters, i.e., pyrolysis and annealing temperatures and durations, were varied to change the microstructure of the films. The functional response of the films was characterized before and after exposure to gamma radiation [up to 10 Mrad(Si)]. Within the total ionization dose studied, all films showed a <5% change in dielectric response and polarization and <15% change in piezoelectric response, after irradiation. While all films showed substantial radiation tolerance, those with large columnar grains showed the highest dielectric and piezoelectric response and, therefore, might offer the best approach for enabling piezoelectric MEMS devices for applications in radiative environments.