Donor variability alters differentiation and mechanical cohesion of tissue-engineered constructs with human endothelial/MSC co-culture

Mesenchymal stem cells and their derived exosomes in multiple sclerosis disease: from paper to practice

Multiple sclerosis (MS) is a chronic neurodegenerative, inflammatory, and demyelinating disease of the central nervous system (CNS). Current medicines are not sufficient to control the inflammation and progressive damage to the CNS that is known in MS. These drawbacks highlight the need for novel treatment options. Cell therapy can now be used to treat complex diseases when conventional therapies are ineffective. Mesenchymal stem cells (MSCs) are a diverse group of multipotential non-hematopoietic stromal cells which have immunomodulatory, neurogenesis, and remyelinating capacity. Their advantageous effects mainly rely on paracrine, cell-cell communication and differentiation properties which introduced them as excellent candidates for MS therapy. Exosomes, as one of the MSCs secretomes, have unique properties that make them highly promising candidates for innovative approach in regenerative medicine. This review discusses the therapeutic potential of MSCs and their derived exosomes as a novel treatment for MS, highlighting the differences between these two approaches.

Substrate topographies modulate the secretory activity of human bone marrow mesenchymal stem cells

BACKGROUND

Mesenchymal stem cells (MSCs) secrete a diversity of factors with broad therapeutic potential, yet current culture methods limit potency outcomes. In this study, we used topographical cues on polystyrene films to investigate their impact on the secretory profile and potency of bone marrow-derived MSCs (hBM-MSCs). hBM-MSCs from four donors were cultured on topographic substrates depicting defined roughness, curvature, grooves and various levels of wettability.

METHODS

The topographical PS-based array was developed using razor printing, polishing and plasma treatment methods. hBM-MSCs from four donors were purchased from RoosterBio and used in co-culture with peripheral blood mononuclear cells (PBMCs) from Cell Applications Inc. in an immunopotency assay to measure immunosuppressive capacity. Cells were cultured on low serum (2%) for 24-48 h prior to analysis. Image-based analysis was used for cell quantification and morphology assessment. Metabolic activity of BM-hMSCs was measured as the mitochondrial oxygen consumption rate using an extracellular flux analyzer. Conditioned media samples of BM-hMSCs were used to quantify secreted factors, and the data were analyzed using R statistics. Enriched bioprocesses were identify using the Gene Ontology tool enrichGO from the clusterprofiler. One-way and two-way ANOVAs were carried out to identify significant changes between the conditions. Results were deemed statistically significant for combined P < 0.05 for at least three independent experiments.

RESULTS

Cell viability was not significantly affected in the topographical substrates, and cell elongation was enhanced at least twofold in microgrooves and surfaces with a low contact angle. Increased cell elongation correlated with a metabolic shift from oxidative phosphorylation to a glycolytic state which is indicative of a high-energy state. Differential protein expression and gene ontology analyses identified bioprocesses enriched across donors associated with immune modulation and tissue regeneration. The growth of peripheral blood mononuclear cells (PBMCs) was suppressed in hBM-MSCs co-cultures, confirming enhanced immunosuppressive potency. YAP/TAZ levels were found to be reduced on these topographies confirming a mechanosensing effect on cells and suggesting a potential role in the immunomodulatory function of hMSCs.

CONCLUSIONS

This work demonstrates the potential of topographical cues as a culture strategy to improve the secretory capacity and enrich for an immunomodulatory phenotype in hBM-MSCs.

COX-2/PGE2/VEGF signaling promotes ERK-mediated BMSCs osteogenic differentiation under hypoxia by the paracrine action of ECs

Understanding the crosstalk between endothelial cells (ECs) and bone-marrow mesenchymal stem cells (BMSCs) in response to hypoxic environments and deciphering of the underlying mechanisms are of great relevance for better application of BMSCs in tissue engineering. Here, we demonstrated that hypoxia promoted BMSCs proliferation, colony formation, osteogenic markers expression, mineralization, and extracellular signal-regulated protein kinase (ERK) phosphorylation, and that PD98059 (ERK inhibitor) blocked hypoxia-induced osteogenic differentiation. Hypoxia enhanced ECs migration, cyclooxygenase 2 (COX-2) and integrin α_vβ₃ expression, and prostaglandin E₂ (PGE₂), vascular endothelial growth factor (VEGF) secretion. NS398 (selective COX-2 inhibitor) and LM609 (integrin α_vβ₃ specific inhibitor) impaired the ECs response to hypoxia, and exogenous PGE₂ partially reversed the effects of NS398. BMSCs: ECs co-culture under hypoxia upregulated BMSCs osteogenesis and ERK phosphorylation, as well as ECs migration, integrin α_vβ₃ expression, and PGE₂ and VEGF secretion. NS398 (pretreated ECs) lessened PGE₂, VEGF concentrations of the co-culture system. NS398-treated ECs and AH6809 (combined EP1/2 antagonist)/L-798106 (selective EP3 antagonist)/L-161982 (selective EP4 antagonist)/SU5416 [VEGF receptor (VEGFR) inhibitor]-treated BMSCs impaired the co-cultured ECs-induced enhancement of BMSCs osteogenic differentiation. In conclusion, hypoxia enhances BMSCs proliferation and ERK-mediated osteogenic differentiation, and augments the COX-2-dependent PGE₂ and VEGF release, integrin α_vβ₃ expression, and migration of ECs. COX-2/PGE₂/VEGF signaling is involved in intercellular BMSCs: ECs communication under hypoxia.