In vitro reprogramming of rat bone marrow-derived mesenchymal stem cells into insulin-producing cells by genetically manipulating negative and positive regulators.

Islet cell replacement therapy represents the most promising approach for the cure of type 1 diabetes if autoimmunity to ß cells is under control. However, this potential is limited by a shortage of pancreas donors. To address the donor shortage problem, we determined whether bone marrow-derived mesenchymal stem cells (bmMSCs) can be directly reprogrammed to islet lineages by simultaneously forced suppression and over-expression of key regulator genes that play critical roles during pancreas development. Here, we report that rat bmMSCs were converted in vitro into insulin-producing cells by suppressing two-repressor genes repressor element-1 silencing transcription factor/neuronal restrictive silencing factor (Rest/Nrsf) and sonic hedgehog (Shh) and by over-expressing pancreas and duodenal transcription factor 1 (Pdx1). The reprogrammed bmMSCs expressed both genes and proteins specific for islet cells. These converted cells were capable of releasing insulin in a glucose-responsive manner. Our study suggests that bmMSCs may ultimately be reprogrammed to functional insulin-secreting cells.

[Construction and identification of the lentiviral vector of repressor element-1/neuron-restrictive silencer element double-stranded RNA].

OBJECTIVE: To construct a lentiviral vector of repressor element-1/neuron-restrictive silencer element (RE-1/NRSE) double-stranded RNA (dsRNA). METHODS: The RE-1/NRSE cDNA containing both sense and antisense oligo DNA fragments of the targeting sequence was synthesized and cloned into the pGC-LV vector. The obtained lentiviral vector containing RE-1/NRSE dsRNA was confirmed by PCR and sequencing. A total of 293T cells were cotransfected with lentiviral vector of L-smNRSE/RE-1, pHelper 1.0, and pHelper 2.0. The titer of virus was measured based on the expression level of green fluorescent protein. The transfection efficiency of green fluorescent protein into rat mesenchymal stem cells was calculated. RESULTS: PCR and DNA sequencing demonstrated that the constructed lentivirus vector of L-smNRSE/RE-1 produced RE-1/NRSE dsRNA.The titer of the concentrated virus was 4x108 TU/m1. The virus was stably transfected into rat mesenchymal stem cells, and the infection efficiency reached 100% when the multiplicity of infection was 80. CONCLUSION: The lentivirus vector of RE-1/NRSE dsRNA is successfully constructed.

[Relationship between neuronal restricted silencing factor and induced differentiation from rat mesenchymal stem cells to neurons].

OBJECTIVE: To analyze the change of the neuronal restricted silencing factor (NRSF) gene as well as the NRSF regulation genes in beta-mercaptoethanol induction of the marrow mesenchymal stem cells (MSCs) to neurons, and to discuss the function of NRSF in neural induction of the MSCs and the mechanism of the differentiation from MSCs to neurons. METHOD: We used beta-mercaptoethanol, serum-free DMEM, and dimethyl sulfoxide to induce rat MSCs to differentiate to neurons, and then analyzed the changes of the expressions of NRSF gene and NRSF-regulated genes through real-time PCR. RESULTS: The rat MSCs were successfully induced to differentiate into neuron-like cells. The induced neuron marker, neuron-specific enolase, was positive. Real-time PCR showed that the expression of NRSF gene remarkably declined. The expressions of neurotrophic tyrosine kinase receptor, type 3, synaptosomal-associated protein 25, L1 cell adhesion molecular,neuronal pentraxin receptor in the NRSF-regulated genes also increased at varied extents. CONCLUSIONS: The differentiation from MSCs to neurons is relevant with the decline of NRSF expression and the increase of the expressions of NRSF-regulated genes. The NRSF may be the key gene during the differentiation from MSCs to neurons.

Sperm DNA fragmentation index, as measured by sperm chromatin dispersion, might not predict assisted reproductive outcome.

OBJECTIVE: Routine semen parameters have limited clinical diagnostic value for predicting male infertility. The aim of this study was to investigate the association between sperm DNA fragmentation index (DFI) and semen quality, and between DFI and clinical pregnancy rate of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). METHODS AND MATERIALS: A total of 390 couples undergoing sperm fragmentation prior to receiving conventional IVF (n = 238) or ICSI (n = 152) were evaluated. RESULTS: We found that there were no significant differences in fertilization rate, good embryo rate, or pregnancy rate between high (≥30%) and low (<30%) DFI groups after IVF or ICSI. However, statistically different decreasing motility trends under higher DFI values in the IVF and ICSI groups were detected. Comparison of ROC curve of motility and DFI scores for achieved pregnancy revealed that the best DFI cut-off value was 20%. Also, no significant change was found when 20% DFI level was taken in IVF and ICSI outcomes. CONCLUSION: DFI scores did not provide independent information regarding fertilization, embryo quality, or pregnancy for infertile patients who received IVF or ICSI, but were consistent with semen analysis for infertile couples, regardless of IVF or ICSI outcome.

In vitro reprogramming of rat bmMSCs into pancreatic endocrine-like cells.

Islet transplantation provides curative treatments to patients with type 1 diabetes, but donor shortage restricts the broad use of this therapy. Thus, generation of alternative transplantable cell sources is intensively investigated worldwide. We previously showed that bone marrow-derived mesenchymal stem cells (bmMSCs) can be reprogrammed to pancreatic-like cells through simultaneously forced suppression of Rest/Nrsf (repressor element-1 silencing transcription factor/neuronal restrictive silencing factor) and Shh (sonic hedgehog) and activation of Pdx1 (pancreas and duodenal transcription factor 1). We here aimed to reprogram bmMSCs further along the developmental pathway towards the islet lineages by improving our previous strategy and by overexpression of Ngn3 (neurogenin 3) and NeuroD1 (neurogenic differentiation 1), critical regulators of the development of endocrine pancreas. We showed that compared to the previous protocol, the overexpression of only Pdx1 and Ngn3 reprogrammed bmMSCs into cells with more characteristics of islet endocrine lineages verified with bioinformatic analyses of our RNA-Seq datasets. These analyses indicated 2325 differentially expressed genes including those involved in the pancreas and islet development. We validated with qRT-PCR analysis selective genes identified from the RNA-Seq datasets. Thus, we reprogrammed bmMSCs into islet endocrine-like cells and advanced the endeavor to generate surrogate functional insulin-secreting cells.

Effect of anesthesia on cognitive status and MMP-2 expression in rats.

OBJECTIVE: To investigate the effect of anesthesia on the cognitive status damage and MMP-2 expression in rats. METHODS: A total of 120 healthy rats were selected and randomly divided into the control group, CF3-CH(OCH2F)-CF3 (Sevoflurane) group and CF3-CH2-O-CHF-CF3 group (Sevoflurane) (n=40). After training for 3 d by the Morris water maze, the control group were injected with fentanyl for analgesia, the CF3-CH(OCH2F)-CF3 group and the CF3-CH2-O-CHF-CF3 group were anesthesia with CF3-CH (OCH2F)-CF3 and CF3-CH2-O-CHF-CF3 on the basis of fentanyl, then rats in three groups underwent open surgery and suture conventional incision. Morris water maze was used to measure the rats' cognitive ability in three groups on the 1st d, 3rd d, 5th d and 7th d, and the brain tissue MMP-2 expression was detected. RESULTS: After 1 d/7 d of the surgery, Morris water maze performance and MMP-2 expression were not significantly different among three groups (P>0.05); After 3 d/5 d of the surgery, compared with the control group, the Morris water maze test result was significantly worsened, MMP-2 expression levels were significantly increased (P<0.05); After 3 d/5 d of the surgery, compared with the CF3-CH2-O-CHF-CF3 group, Morris water maze test result of CF3-CH(OCH2F)-CF3 group was significantly worsened, MMP-2 expression levels were significantly increased (P<0.05). CONCLUSIONS: Anesthesia can cause some injury on cognitive status, different anesthetic drugs may cause different injury, and the cognitive status injury is related to the MMP-2 expression.