IL-1ß primed mesenchymal stromal cells moderate hemorrhagic shock-induced organ injuries.

BACKGROUND: Organ damages following hemorrhagic shock (HS) have been partly attributed to an immunological dysfunction. The current challenge in the management of HS patients is to prevent organ injury-induced morbidity and mortality which currently has not etiological treatment available. Mesenchymal stromal cells (MSC) are used in clinical cell therapy for immunomodulation and tissue repair. In vitro priming is often used to improve the immunomodulation efficiency of MSC before administration. OBJECTIVE: Assess the effect of naive MSC (MSCn) or interleukin (IL)-1ß primed (MSCp) treatment in a context of HS-induced organ injury. METHODS: Rats underwent fixed pressure HS and were treated with allogenic MSCn or MSCp. Liver and kidney injuries were evaluated 6h later by histological and biochemical analysis. Whole blood was collected to measure leukocytes phenotypes. Then, in vitro characterization of MSCn or MSCp was carried out. RESULTS: Plasma creatinine, blood urea nitrogen, and cystatin C were decrease by MSCp infusion as well as kidney injury molecule (KIM)-1 on histological kidney sections. Transaminases, GGT, and liver histology were normalized by MSCp. Systemic cytokines (IL-1α, IL-6, and IL-10) as well as CD80, 86, and PD-1/PDL-1 axis were decreased by MSCp on monocytes and granulocytes. In vitro, MSCp showed higher level of secreted immunomodulatory molecules than MSCn. CONCLUSION: An early administration of MSCp moderates HS-induced kidney and liver injury. IL-1ß priming improves MSC efficiency by promoting their immunomodulatory activity. These data provide proof of concept that MSCp could be a therapeutic tool to prevent the appearance of organs injury following HS.

Interferon-γ and Hypoxia Priming Have Limited Effect on the miRNA Landscape of Human Mesenchymal Stromal Cells-Derived Extracellular Vesicles.

Mesenchymal stromal cell (MSC)-based cell therapy has received great interest in regenerative medicine. Priming the cells during the culture phase can improve their efficacy and/or survival after injection. The literature suggests that MSC extracellular vesicles (EV) can recapitulate a substantial part of the beneficial effects of the cells they originate from, and that micro-RNAs (miRNAs) are important players in EV biological action. Here, our aim was to determine if two classical priming methods of MSC, interferon-gamma (IFNγ) and hypoxia (HYP), could modify their EV miRNA content. Human bone marrow MSCs (BM-MSCs) from five healthy donors were cultured with IFNγ or in HYP or in control (CONT) conditions. The conditioned media were collected after 48 h in serum-free condition and EV were isolated by ultracentrifugation. Total RNA was isolated, pools of CONT, IFN, and HYP cDNA were prepared, and a miRNA profiling was performed using RT-qPCR. Then, miRNAs were selected based on their detectability and measured on each individual EV sample. Priming had no effect on EV amount or size distribution. A set of 81 miRNAs was detected in at least one of the pools of EVs. They were measured on each individual sample; 41 miRNAs were detected in all samples. The principal component analysis (PCA) failed to discriminate the groups. HYP induced a significant decrease in EV hsa-miR-34a-3p content and IFN induced a significant increase in five miRNAs (hsa-miR-25-3p, hsa-miR-106a-5p, hsa-miR-126-3p, hsa-miR-451a, and hsa-miR-665). Taken together, we found only limited alterations in the miRNA landscape of MSC EV with a high inter-individual variability.

Self-Assembled Collagen Microparticles by Aerosol as a Versatile Platform for Injectable Anisotropic Materials.

Extracellular matrices (ECM) rich in type I collagen exhibit characteristic anisotropic ultrastructures. Nevertheless, working in vitro with this biomacromolecule remains challenging. When processed, denaturation of the collagen molecule is easily induced in vitro avoiding proper fibril self-assembly and further hierarchical order. Here, an innovative approach enables the production of highly concentrated injectable collagen microparticles, based on collagen molecules self-assembly, thanks to the use of spray-drying process. The versatility of the process is shown by performing encapsulation of secretion products of gingival mesenchymal stem cells (gMSCs), which are chosen as a bioactive therapeutic product for their potential efficiency in stimulating the regeneration of a damaged ECM. The injection of collagen microparticles in a cell culture medium results in a locally organized fibrillar matrix. The efficiency of this approach for making easily handleable collagen microparticles for encapsulation and injection opens perspectives in active tissue regeneration and 3D bioprinted scaffolds.