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IntroductionRecent evidence suggests that the implantation of bone marrow-derived mesenchymal stem cells improves peripheral nerve regeneration. In this study we aimed to investigate whether adipose-derived stem cells (ADSCs) can be used for peripheral nerve repair.Material and methodsIn a rat model, nerve regeneration was evaluated across a 15 mm lesion in the sciatic nerve by using an acellular nerve injected with allogenic ADSCs. The walking behaviour of rats was measured by footprint analysis, and electrophysiological analysis and histological examination were performed to evaluate the efficacy of nerve regeneration.ResultsCultured ADSCs became morphologically homogeneous with a bipolar, spindle-like shape after ex vivo expansion. Implantation of ADSCs into the rat models led to (i) improved walking behaviour as measured by footprint analysis, (ii) increased conservation of muscle-mass ratio of gastrocnemius and soleus muscles, (iii) increased nerve conduction velocity, and (iv) increased number of myelinated fibres within the graft.ConclusionsAdipose-derived stem cells could promote peripheral nerve repair in a rat model. Although the detailed mechanism by which ADSCs promote peripheral nerve regeneration is being investigated in our lab, our results suggest that ADSCs transplantation represents a powerful therapeutic approach for peripheral nerve injury.

Resistance to chemotherapy is a major obstacle for the effective treatment of cancers. Lin28 has been shown to contribute to tumor relapse after chemotherapy; however, the relationship between Lin28 and chemoresistance remained unknown. In this study, we investigated the association of Lin28 with paclitaxel resistance and identified the underlying mechanisms of action of Lin28 in human breast cancer cell lines and tumor tissues. We found that the expression level of Lin28 was closely associated with the resistance to paclitaxel treatment. The T47D cancer cell line, which highly expresses Lin28, is more resistant to paclitaxel than the MCF7, Bcap-37 or SK-BR-3 cancer cell lines, which had low-level expression of Lin28. Knocking down of Lin28 in Lin28 high expression T47D cells increased the sensitivity to paclitaxel treatment, while stable expression of Lin28 in breast cancer cells effectively attenuated the sensitivity to paclitaxel treatment, resulting in a significant increase of IC50 values of paclitaxel. Transfection with Lin28 also significantly inhibited paclitaxel-induced apoptosis. We also found that Lin28 expression was dramatically increased in tumor tissues after neoadjuvant chemotherapy or in local relapse or metastatic breast cancer tissues. Moreover, further studies showed that p21, Rb and Let-7 miRNA were the molecular targets of Lin28. Overexpression of Lin28 in breast cancer cells considerably induced p21 and Rb expression and inhibited Let-7 miRNA levels. Our results indicate that Lin28 expression might be one mechanism underlying paclitaxel resistance in breast cancer, and Lin28 could be a potential target for overcoming paclitaxel resistance in breast cancer.

Abstract:Our former study demonstrated that Krüppel-like Factor 7 (KLF7) is a transcription factor that stimulates axonal regeneration after peripheral nerve injury. Currently, we used a gene therapy approach to overexpress KLF7 in Schwann Cells (SCs) and assessed whether KLF7-transfected SCs graft could promote sciatic nerve regeneration. SCs were transfected by AAV2-KLF7 in vitro. Mice was allografted by an acellular nerve (ANA) with either an injection of DMEM (ANA group), SCs (ANA+SCs group) or AAV2-KLF7-transfected SCs (ANA+KLF7-SCs group) to assess repair of a sciatic nerve gap. The results indicate that KLF7 overexpression promoted the proliferation of both transfected SCs and native SCs. The neurite length of the DRG explants was enhanced.Several beneficial effects were detected in the ANA+KLF7-SCs group including an increase in the compound action potential amplitude , sciatic function index score, enhanced expression of PKH26-labeling transplant SCs, peripheral myelin protein 0 , neurofilaments , S-100, and myelinated regeneration nerve.Additionally, HRP-labeled motoneurons in the spinal cord, CTB-labeled sensory neurons in the DRG, motor endplate density and the weight ratios of target muscles were increased by the treatment while thermal hyperalgesia was diminished. Finally, expression of KLF7, NGF, GAP43, TrkA and TrkB were enhanced in the grafted SCs, which may indicate that several signal pathways may be involved in conferring the beneficial effects from KLF7 overexpression. We concluded that KLF7-overexpressing SCs promoted axonal regeneration of the peripheral nerve and enhanced myelination, which collectively proved KLF-SCs as a novel therapeutic strategy for injured nerves.

Abstract. Mesenchymal stem cells have become a very attractive source of cell implantation for neural tissue engineering. The ideal stem cells for transplantation should be easily obtained, and should rapidly proliferate in vitro and have low immunogenicity. The purpose of this study was to investigate the regenerative potential of adipose-derived stem cells (ADSC) on peripheral nerve repair. ADSCs were isolated from rat adipose tissue and cultured until adherent cells became morphologically homogeneous with a fibroblast-like shape, and transplanted with acellular nerve allografts (ANAs) into rat models with a 10 mm gap of transected sciatic nerve defect. After cell transplantation, we found that ADSC implantation improved functional recovery of exercise behavior and increased wet weight ratio of the anterior tibial muscle. In the electrophysiological testing, we found that the percentage of activated fibers was higher in the ADSC-implanted animals as evidenced by the increase of nerve conduction velocity and amplitude. Histological examination revealed that the number of nerve fibers, axonal diameter and myelin thickness were significantly higher in the ADSC-implanted animals compared to the control. In addition, we demonstrated that the progression of the regenerative process after ADSC implantation was accompanied by elevated expression of neurotrophic factors at both the early and later phase. Taken together, these results suggest that ADSCs can promote the repair of peripheral nerve injury, and the combination of ADSC and ANA transplantation is a new therapeutic method for long distant peripheral nerve defects. Our data also provide evidence indicating the strong association of neurotrophic factor production to the regenerative potential of implanted ADSCs. IntroductionTraditional therapeutic approaches for the reconstruction of peripheral nerve defects include end-to-end suturing, fascicular suturing, nerve graft, and nerve conduits. There is evidence indicating that nerve grafting is essential for reconstruction of long nerve defects. Recently, neural tissue engineering has received much attention, and Schwann cell transplantation has been reported to achieve reliable outcomes in the regeneration of the sciatic nerve (1-3). However, Schwann cell isolation can cause additional damage, and these cells need a long time for cell culture and growth, which have limited their clinical application.Mesenchymal stem cells (MSC) have recently become a very attractive source of cell implantation for tissue engineering because of their self-proliferation, fast proliferation and multilineage differentiation potential (4). A large number of studies have shown that bone marrow-derived mesenchymal stem cells (BMMSC) can promote the repair of peripheral nervous system injury (5-11). Chen et al (11) found that rat BMMSC can synthesize and secrete a number of neurotrophic factors (NF), including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factors (CNTF) and glial cell line-derive...

Recently it was demonstrated that the exposure of the developing brain during the period of synaptogenesis to drugs that block NMDA glutamate receptors can trigger widespread apoptotic neurodegeneration. Sevoflurane is a new inhalation anesthetic agent commonly used in the clinic. Here we address whether sevoflurane could induce neurotoxicity in the developing brain. Sevoflurane was administered to rats before pregnancy and pregnant rats on embryonic days E6, E10, E14, and E18 1MAC for 6 h, and we employed histopathological, immunochemistry, semiquantitative RT-PCR, and Western blot to investigate the effect of the exposure of pregestation and gestation rats to sevoflurane on the offspring brain development. The results showed that the exposure of gestation but not pregestation rats to sevoflurane-induced extensive apoptotic neurodegeneration in the hippocampus of offspring at P0, P7, and P14, accompanied by altered expression of casepase-3, GAP-43, nNOS, NMDAR1, NMDAR2A, and NMDAR2B. Furthermore, upregulation of PKCα and p-JNK and downregulation of p-ERK and FOS protein levels were observed in the hippocampus of offspring at P0, P7, and P14 from rats exposed to sevoflurane at gestation, but not pregestation. In summary, our data suggest that sevoflurane induces developmental neurotoxicity in rats and this may be attributed to the upregulation of PKCα and p-JNK and downregulation of p-ERK and FOS protein in the hippocampus.

The genesis and development of hepatocellular carcinoma (HCC) is related to the abnormity of signaling pathway, telomerase, cell cycle, apoptosis, angiogenesis, and others, in which STAT3 signaling pathway plays a key role. The HCC cell line HepG 2 was transfected with small interfering RNA (siRNA) directed against STAT3. After 72 h, cell growth and cycle were analysed by MTT and Flow cytometry. Then, the protein was extracted and the protein expression of STAT3, Smad3, p44/42, TERT, caspase-3, XIAP, Grp-78, HSP-27, MMP-2, MMP-9, VEGF-A, cyclin A, and cyclin E was detected by Western blot. After the transfection, HCC cell growth was inhibited during the 24-72 h time period and the cell cycle was arrested in G0/G1. STAT3 protein expression was inhibited at 72 h after the transfection. Interestingly, Smad3, p-caspase-3, p-p44/42, Grp78, cyclin A, and cyclin E protein expression was increased at 72 h, while TERT, caspase-3, XIAP, MMP-2, MMP-9, and VEGF-A protein expression decreased at 72 h. However, P44/42, and HSP27 protein expression showed no change following transfection. The results demonstrated that STAT3 signaling pathway may participate in HCC genesis and development through regulating the protein expression of other signaling pathway, telomerase, apoptosis, cell cycle and angiogenesis; thereby, blockade of the Stat3 pathway represents a potential strategy for future treatment.

The present study was designed to investigate the myocardial expression of liver X receptor alpha (LXRα) in a streptozotocin (STZ)-induced diabetic rat model. Immunohistochemical staining, quantitative real-time RT-PCR, and Western blot analysis were used to determine the expression of LXRα in the myocardium of STZ-induced diabetic rats. The myocardial expression of LXRα target genes, long-chain acyl-CoA synthetase 3 (ACSL3), fatty acid transporter protein (FAT/CD36), ATP-binding cassette transporter A1 (ABCA1), and ABCG1 were also detected. Bisulfite sequencing analysis was employed to examine the methylation status of the CpG island at the LXRα promoter region in the myocardium of STZ-induced diabetic rats. We found that LXRα mRNA and protein expression in the left ventricles, right ventricles, and atria of diabetic rats were gradually increased during the progression of diabetic cardiomyopathy (DCM). The mRNA expression levels of ACSL3 and FAT/CD36 and the protein expression levels of ABCA1 and ABCG1 were also markedly increased in different heart chambers of diabetic rats. Moreover, there was a significant difference in the methylation status of LXRα gene between the ventricles of control and diabetic rats (P < 0.05). Our findings suggest that elevated expression of LXRα may be involved in the progression of DCM, and demethylation of LXRα is likely to be responsible for its increased expression in myocardial tissues.