The effects of canine bone marrow stromal cells on neuritogenesis from dorsal root ganglion neurons in vitro

Repair of Peripheral Nerve Sensory Impairments via the Transplantation of Bone Marrow Neural Tissue-Committed Stem Cell-Derived Sensory Neurons

The present study aimed to investigate the efficacy of transplantation of bone marrow neural tissue-committed stem cell-derived sensory neuron-like cells for the repair of peripheral nerve sensory impairments in rats. Bone marrow was isolated and cultured to obtain the neural tissue-committed stem cells (NTCSCs), and the differentiation of these cells into sensory neuron-like cells was induced. Bone marrow mesenchymal stem cells (BMSCs), bone marrow NTCSCs, and bone marrow NTCSC-derived sensory neurons (NTCSC-SNs) were transplanted by microinjection into the L4 and L5 dorsal root ganglions (DRGs) in an animal model of sensory defect. On the 2nd, 4th, 8th, and 12th week after the transplantation, the effects of the three types of stem cells on the repair of the sensory functional defect were analyzed via behavioral observation, sensory function evaluation, electrophysiological examination of the sciatic nerve, and morphological observation of the DRGs. The results revealed that the transplanted BMSCs, NTCSCs, and NTCSC-SNs were all able to repair the sensory nerves. In addition, the effect of the NTCSC-SNs was significantly better than that of the other two types of stem cells. The general posture and gait of the animals in the sensory defect model exhibited evident improvement over time. Plantar temperature sensitivity and pain sensitivity gradually recovered, and the sensation latency was reduced, with faster sensory nerve conduction velocity. Transplantation of NTCSC-SNs can improve the repair of peripheral nerve sensory defects in rats.

Activation of MEK/ERK pathways through NF-κB activation is involved in interleukin-1β-induced cyclooxygenease-2 expression in canine dermal fibroblasts

The proinflammatory cytokine interleukin-1β (IL-1β) induced cyclooxygenases-2 (COX-2) mRNA expression and lipid mediator prostaglandin E2 release and in a time- and dose-dependent manner in canine dermal fibroblasts. The MEK inhibitor U0126 and the ERK inhibitor FR180204 clearly inhibited IL-1β-induced prostaglandin E2 release and COX-2 mRNA expression. IL-1β enhanced ERK1/2 phosphorylation, which was attenuated by inhibitors of MEK and ERK. The NF-κB inhibitor BAY 11-7082 also suppressed IL-1β-induced prostaglandin E2 release and COX-2 mRNA expression. Treatment of fibroblasts with IL-1β led to the phosphorylation of p65 and degradation of IκBα occurred, indicating that IL-1β treatment activated NF-κB. MEK and ERK1/2 inhibitors had no effect on the phosphorylation of p65 subunit induced by IL-1β, whereas the NF-κB inhibitor completely blocked IL-1β-induced phosphorylation of ERK1/2. We also observed that IκBα-knockdown enhanced the phosphorylation of p65 and ERK1/2. These findings suggest that stimulation of MEK/ERK signaling pathway by NF-κB activation regulates IL-1β-induced COX-2 expression and subsequent prostaglandin E2 release in canine dermal fibroblasts.

Sensory neurons and osteoblasts: close partners in a microfluidic platform

We presented a microfluidic-based coculture system as a new tool to be explored for modeling biological processes and pharmacological screening concerning peripheral tissues innervation.

Bone mesenchymal stromal cells stimulate neurite outgrowth of spinal neurons by secreting neurotrophic factors

It has been demonstrated that bone mesenchymal stromal cells (BMSCs) stimulate neurite outgrowth from dorsal root ganglion (DRG) neurons. The present in vitro study tested the hypothesis that BMSCs stimulate the neurite outgrowth from spinal neurons by secreting neurotrophic factors. Spinal neurons were cocultured with BMSCs, fibroblasts and control medium in a non-contact system. Neurite outgrowth of spinal neurons cocultured with BMSCs was significantly greater than the neurite outgrowth observed in neurons cultured with control medium or with fibroblasts. In addition, BMSC-conditioned medium increased the length of neurites from spinal neurons compared to those of neurons cultured in the control medium or in the fibroblasts-conditioned medium. BMSCs expressed brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF). The concentrations of BDNF and GDNF in BMSC-conditioned medium were 132±12 and 70±6 pg ml(-1), respectively. The addition of anti-BDNF and anti-GDNF antibodies to BMSC-conditioned medium partially blocked the neurite-promoting effect of the BMSC-conditioned medium. In conclusion, our results demonstrate that BMSCs promote neurite outgrowth in spinal neurons by secreting soluble factors. The neurite-promoting effect of BMSCs is partially mediated by BDNF and GDNF.

Axon growth-promoting properties of human bone marrow mesenchymal stromal cells

Mesenchymal stromal cells are promising candidate donor cells for promoting functional tissue repair following traumatic spinal cord injury (SCI), however, the mechanism(s) of action remain poorly defined. Here, we describe an in vitro study of the axon growth-promoting properties of highly enriched populations of adult human mesenchymal stromal cells (hMSC). A random, non-oriented pattern of neuritic outgrowth was observed from dissociated adult rat DRG neurons seeded onto confluent A431 cells and PLL/laminin positive control substrata. Confluent hMSC formed arrays of similarly orientated cell bodies and processes which supported the regeneration of significantly more primary neurites but a slightly lower overall neuritic length than was observed over the PLL/laminin control substrate. The hMSC exerted a strong influence on the direction of neuritic outgrowth, with many regenerating processes following the orientation of underlying hMSC. The production of extracellular matrix appeared to be responsible for neuritic directionality, but the release of growth factors was a significant promoter for DRG neuritic outgrowth. This suggests that further investigations into the properties of hMSC may be of particular interest in the development of transplant-mediated strategies intending to promote functional axonal regeneration after SCI.

Synphilin-1 exhibits trophic and protective effects against Rotenone toxicity

Synphilin-1 is a cytoplasmic protein with unclear function. Synphilin-1 has been identified as an interaction partner of alpha-synuclein. The interaction between synphilin-1 and alpha-synuclein has implications in Parkinson's disease. In this study, we stably overexpressed human synphilin-1 in mouse N1E-115 neuroblastoma cells. We found that overexpression of synphilin-1 shortened cell growth doubling time and increased neurite outgrowth. Knockdown of endogenous synphilin-1 caused neuronal toxicity and shortened neurite outgrowth. We further found that synphilin-1 increased activation of the extracellular signal-regulated kinases (ERK1/2) and mediated neurite outgrowth. Rotenone, mitochondrial complex I inhibitor, has been shown previously to induce dopaminergic neurodegeneration and Parkinsonism in rats and Drosophila. We found that Rotenone induced apoptotic cell death in N1E-115 cells via caspase-3 activation and poly (ADP-ribose) polymerase (PARP) cleavage. Overexpression of synphilin-1 significantly reduced Rotenone-induced cell death, caspase-3 activation and PARP cleavage. The results indicate that synphilin-1 displays trophic and protective effects in vitro, suggesting that synphilin-1 may play a protective role in Parkinson's disease (PD) pathogenesis and may lead to a potential therapeutic target for PD intervention.