Marrow-derived Multipotent Progenitor Cells Research Articles

Extracellular matrix-regulated neural differentiation of human multipotent marrow progenitor cells enhances functional recovery after spinal cord injury

Background contextRecent advanced studies have demonstrated that cytokines and extracellular matrix (ECM) could trigger various types of neural differentiation. However, the efficacy of differentiation and in vivo transplantation has not yet thoroughly been investigated. PurposeTo highlight the current understanding of the effects of ECM on neural differentiation of human bone marrow-derived multipotent progenitor cells (MPCs), regarding state-of-art cure for the animal with acute spinal cord injury (SCI), and explore future treatments aimed at neural repair. Study designA selective overview of the literature pertaining to the neural differentiation of the MSCs and experimental animals aimed at improved repair of SCI. MethodsExtracellular matrix proteins, tenascin-cytotactin (TN-C), tenascin-restrictin (TN-R), and chondroitin sulfate (CS), with the cytokines, nerve growth factor (NGF)/brain-derived neurotrophic factor (BDNF)/retinoic acid (RA) (NBR), were incorporated to induce transdifferentiation of human MPCs. Cells were treated with NBR for 7 days, and then TN-C, TN-R, or CS was added for 2 days. The medium was changed every 2 days. Twenty-four animals were randomly assigned to four groups with six animals in each group: one experimental and three controls. Animals received two (bilateral) injections of vehicle, MPCs, NBR-induced MPCs, or NBR/TN-C-induced MPCs into the lesion sites after SCI. Functional assessment was measured using the Basso, Beattie, and Bresnahan locomotor rating score. Data were analyzed using analysis of variance followed by Student-Newman-Keuls (SNK) post hoc tests. ResultsResults showed that MPCs with the transdifferentiation of human MPCs to neurons were associated with increased messenger-RNA (mRNA) expression of neuronal markers including nestin, microtubule-associated protein (MAP) 2, glial fibrillary acidic protein, βIII tubulin, and NGF. Greater amounts of neuronal morphology appeared in cultures incorporated with TN-C and TN-R than those with CS. The addition of TN-C enhanced mRNA expressions of MAP2, βIII tubulin, and NGF, whereas TN-R did not significantly change. Conversely, CS exposure decreased MAP2, βIII tubulin, and NGF expressions. The TN-C-treated MSCs significantly and functionally repaired SCI-induced rats at Day 42. Present results indicate that ECM components, such as tenascins and CS in addition to cytokines, may play functional roles in regulating neurogenesis by human MPCs. ConclusionsThese findings suggest that the combined use of TN-C, NBR, and human MPCs offers a new feasible method for nerve repair.

The ERK5 and ERK1/2 signaling pathways play opposing regulatory roles during chondrogenesis of adult human bone marrow‐derived multipotent progenitor cells

Adult human bone marrow-derived multipotent progenitor cells (MPCs) are able to differentiate into a variety of specialized cell types, including chondrocytes, and are considered a promising candidate cell source for use in cartilage tissue engineering. In this study, we examined the regulation of MPC chondrogenesis by mitogen-activated protein kinases in an attempt to better understand how to generate hyaline cartilage in the laboratory that more closely resembles native tissue. Specifically, we employed the high-density pellet culture model system to assess the roles of ERK5 and ERK1/2 pathway signaling in MPC chondrogenesis. Western blotting revealed that high levels of ERK5 phosphorylation correlate with low levels of MPC chondrogenesis and that as TGF-beta 3-enhanced MPC chondrogenesis proceeds, phospho-ERK5 levels steadily decline. Conversely, levels of phospho-ERK1/2 paralleled the progression of MPC chondrogenesis. siRNA-mediated knockdown of ERK5 pathway components MEK5 and ERK5 resulted in increased MPC pellet mRNA transcript levels of the cartilage-characteristic marker genes SOX9, COL2A1, AGC, L-SOX5, and SOX6, as well as enhanced accumulation of SOX9 protein, collagen type II protein, and Alcian blue-stainable proteoglycan. In contrast, knockdown of ERK1/2 pathway members MEK1 and ERK1 decreased expression of all chondrogenic markers tested. Finally, overexpression of MEK5 and ERK5 also depressed MPC chondrogenesis, as indicated by diminished activity of a co-transfected collagen II promoter-luciferase reporter construct. In conclusion, our results suggest a novel role for the ERK5 pathway as an important negative regulator of adult human MPC chondrogenesis and illustrate that the ERK5 and ERK1/2 kinase cascades play opposing roles regulating MPC cartilage formation.

Long-term functional improvement and gene expression changes after bone marrow-derived multipotent progenitor cell transplantation in myocardial infarction

The study examined the long-term outcome of cardiac stem cell transplantation in hearts with postinfarction left ventricular (LV) remodeling. Myocardial infarction (MI) was created by ligating the first and second diagonal branches of the left anterior descending coronary artery in miniature swine. Intramyocardial injections of 50 million LacZ-labeled bone marrow-derived multipotent progenitor cells (MPC) were performed in the periscar region (Cell, n = 7) immediately after MI, whereas, in control animals (Cont, n = 7), saline was injected. Functional outcome was assessed monthly for 4 mo with MRI and (31)P-magnetic resonance spectroscopy. Engraftment was studied on histology, and gene chip (Affymetrix) array analysis was used to study differential expression of genes in the two groups. MPC treatment resulted in improvement of ejection fraction as early as 10 days after MI (Cell, 43.4 +/- 5.1% vs. Cont, 32.2 +/- 5.5%; P < 0.05). This improvement was seen each month and persisted to 4 mo (Cell, 51.2 +/- 4.8% vs. Cont, 35.7 +/- 5.0%; P < 0.05). PCr-to-ATP ratio (PCr/ATP) improved with MPC transplantation, which was most pronounced at high cardiac work states (subendocardial PCr/ATP was 1.70 +/- 0.10 vs. 1.34 +/- 0.14, P < 0.05). There was no significant difference in scar size (scar/LV area * 100) at 10 days postinfarction. However, at 4 mo, there was a significant decrease in scar size in the Cell group (Cell, 4.6 +/- 1.0% vs. Cont, 8.6 +/- 2.4%; P < 0.05). No significant engraftment of MPC was observed. MPC transplantation was associated with a downregulation of mitochondrial oxidative enzymes and increased levels of myocyte enhancer factor 2a and zinc finger protein 91. In conclusion, MPC transplantation leads to long-term functional and bioenergetic improvement in a porcine model of postinfarction LV remodeling, despite no significant engraftment of stem cells in the heart. MPC transplantation reduces regional wall stresses and infarct size and mitigates the adverse effects of LV remodeling, as seen by a reduction in LV hypertrophy and LV dilatation, and is associated with differential expression of genes relating to metabolism and apoptosis.