Extracellular matrix from hiPSC-mesenchymal progenitors modulates the three-lineage differentiation of human bone marrow stromal cells

Mesenchymal stromal cells from the bone marrow (BMSCs) exhibit a functional decline during aging. We previously found that extracellular matrix (ECM) engineered from human induced pluripotent stem cell-derived mesenchymal progenitors enhances the osteogenic capacity of BMSCs. In the current study, we investigated how this ECM affects the three-lineage differentiation and secretory activity of BMSCs. BMSCs were seeded on the ECM layer and osteogenic, adipogenic and chondrogenic lineages were induced in monolayer or micromass cultures. Differentiation responses were compared to controls on tissue culture plastic after 21 days, and secretion of interleukin 6 was evaluated after 3 and 21 days of culture. We found a significant increase in BMSC growth on the ECM in all three differentiation media compared with controls. Osteogenic cultures on the ECM resulted in significantly higher alkaline phosphatase activity, osteogenic gene expression, collagen deposition, and matrix mineralization. In adipogenic cultures, a significant decline in adipocyte formation was found on the ECM. Chondrogenic induction on the ECM resulted in significantly increased chondrogenic gene expression, glycosaminoglycans deposition and collagen type II deposition, and no significant increase in collagen type X gene expression compared to control. Secretion of interleukin 6 was modulated by the three differentiation media and culture surface, and was reduced after 21 days of osteogenic and chondrogenic induction on the ECM. Together, our data suggest that engineered ECM modulates BMSCs trilineage differentiation toward enhanced osteogenesis and chondrogenesis, and reduced adipogenesis. Thus, our ECM might provide a bioactive component for enhancing osteochondral regeneration in older patients

Osteosarcoma Cells and Undifferentiated Human Mesenchymal Stromal Cells Are More Susceptible to Ferroptosis than Differentiated Human Mesenchymal Stromal Cells

Current research suggests that promoting ferroptosis, a non-apoptotic form of cell death, may be an effective therapy for osteosarcoma, while its inhibition could facilitate bone regeneration and prevent osteoporosis. Our objective was to investigate whether the susceptibility to and regulation of ferroptosis differ between undifferentiated (UBC) and differentiated (DBC) human bone marrow stromal cells, as well as human osteosarcoma cells (MG63). Ferroptosis was induced by either inhibiting glutathione peroxidase 4 (GPX4) using RSL3 or blocking all glutathione-dependent enzymes through inhibition of the glutamate/cysteine antiporter with Erastin. Lipid peroxidation was assessed using the fluorescent probe BODIPY™581/591C11, while Ferrostatin-1 was used to inhibit ferroptosis. We demonstrate that neither Erastin nor RSL3 induces ferroptosis in DBC. However, both RSL3 and Erastin induce ferroptosis in UBC, while Erastin predominantly induces ferroptosis in MG63 cells. Our data suggest that ferroptosis induction in undifferentiated hBMSCs is primarily regulated by GPX4, whereas glutathione S-Transferase P1 (GSTP1) plays a key role in controlling ferroptosis in osteosarcoma cells. In conclusion, targeting the key pathways involved in ferroptosis across different bone cell types may improve the efficacy of cancer treatments while minimizing collateral damage and supporting regenerative processes, with minimal impact on cancer therapy

Bone-marrow-derived mesenchymal stromal cells: from basic biology to applications in bone tissue engineering and bone regeneration

Bone marrow provides a rich source of mesenchymal stromal cells (MSCs), which have the remarkable capacity for cell and tissue regeneration. Since their initial discovery in the guinea pig almost 50 years ago, bone-marrow-derived MSCs have been extensively studied in animals and humans. Several subpopulations have been characterized with the aim to isolate, enrich, and identify the cells with stem-cell properties and immunomodulatory actions, which are important for regenerative medicine. In this chapter, we review the properties of bone-marrow-derived MSCs with a focus on the preclinical setting and discuss their applications for bone tissue engineering and bone regeneration