TNF-α respecifies human mesenchymal stem cells to a neural fate and promotes migration toward experimental glioma

Abstract

Bone marrow-derived human mesenchymal stem cells (hMSCs) have become valuable candidates for cell-based therapeutical applications including neuroregenerative and anti-tumor strategies. Yet, the molecular mechanisms that control hMSC transdifferentiation to neural cells and hMSC tropism toward glioma remain unclear. Here, we demonstrate that hMSCs incubated with 50 ng/ml tumor necrosis factor alpha (TNF-a) acquired astroglial cell morphology without affecting proliferation, which was increased at 5 ng/ml. TNF-a (50 ng/ml) upregulated expression of numerous genes important for neural cell growth and function including LIF (leukemia inhibitory factor), BMP2 (bone morphogenetic protein 2), SOX2 (SRY box 2), and GFAP (glial fibrillary acidic protein), whereas NES (human nestin) transcription ceased suggesting a premature neural phenotype in TNF-adifferentiated hMSCs. Studies on intracellular mitogen-activated protein kinase (MAPK) signaling revealed that inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) activity abolished the TNF-a-mediated regulation of neural genes in hMSCs. In addition, TNF-a significantly enhanced expression of the chemokine receptor CXCR4 (CXC motive chemokine receptor 4), which facilitated the chemotactic invasiveness of hMSCs toward stromal cell-derived factor 1 (SDF-1) alpha. TNF-a-pretreated hMSCs not only exhibited an increased ability to infiltrate glioma cell spheroids dependent on matrix metalloproteinase activity in vitro, but they also showed a potentiated tropism toward intracranial malignant gliomas in an in vivo mouse model. Taken together, our results provide evidence that culture-expansion of hMSCs in the presence of TNF-a triggers neural gene expression and functional capacities, which could improve the use of hMSCs in the treatment of neurological disorders including malignant gliomas.

Dedifferentiation-Reprogrammed Mesenchymal Stem Cells with Improved Therapeutic Potential

“…Conversely, it has been shown that fetal and adult MSCs are killed by different pathways; in particular, fetal MSCs are preferably killed via TNF a while the adult MSCs are more sensitive to FasL pathway [57]. More intriguingly, a recent study has revealed that TNF a by its own can specify human MSCs to a neural fate [58]. Based on these findings, while the final biological significance of these TNF family members in the complex apoptosis mechanism of MSCs is still elusive, we speculate that the enhanced survival in De-MSCs might be related to the downregulation of TNF receptor 1 and Fas pathway, which requires further investigation in future.…”

Tissue inhibitor of metalloproteinase-1 (TIMP-1) regulates mesenchymal stem cells through let-7f microRNA and Wnt/β-catenin signaling

“…The subcellular localization of β-catenin protein in the hMSCs was examined by immunocytochemistry as previously described (8). Culture slides were incubated with mouse anti-β-catenin antibodies (Santa Cruz Biotechnology) at a dilution of 1:500 in a solution containing 0.5% Triton X-100 and 10% normal goat serum (NGS) for 2 h at 37°C.…”

“…The cells were positive for CD105, CD166, CD29, and CD44 and negative for CD14, CD34, and CD45. hMSCs were cultured as described previously, using the mesenchymal stemcell growth medium (MSCGM) BulletKit (Lonza) (8). For experiments under serum-free conditions, hMSCs were washed with serum-free medium and incubated in DMEM supplemented with 1% Nutridoma SP (Roche Applied Science) in the presence or absence of 20 nM human recombinant TIMP-1 (Peprotech), the null-inhibition mutant Val-Val-TIMP-1, or its active analog WT TIMP-1, both kindly provided by P. Nelson, Ludwig-Maximilians-University.…”

Contribution of SDF-1a/CXCR4 Signaling to Brain Development and Glioma Progression

“…As for human endothelial cells, TNF-α has a biphasic effect on CXCR4 expression, with early inhibition and late induction [138]. Furthermore, TNF-α augments expression of CXCR4 on bone marrow-derived hMSCs, which elevates SDF-1α-induced migration of hMSCs to intracranial gliomas [139]. But Han et al [140] reported that CXCR4 expression is reduced by exposure to TNF-α in primary mouse astrocytes.…”