Epigenetic modifications such as DNA methylation, histone post-translational modifications, non-coding RNA are reversible, heritable alterations which are induced by environmental stimuli. Major risk factors of diabetes and diabetic complications including hyperglycemia, oxidative stress and advanced glycation end products, can lead to abnormal epigenetic modifications in retinal vascular endothelial cells and retinal pigment epithelium cells. Epigenetic mechanisms are involved in the pathogenesis of macular edema and neovascularization of diabetic retinopathy (DR), as well as diabetic metabolic memory. The heritable nature of epigenetic marks also playsakey role in familial diabetes mellitus. Further elucidation of epigenetic mechanisms in DR can open the way for the discovery of novel therapeutic targets to prevent DR progression.
Objective To construct a replicationdefective recombinant adinovirus including the target gene human bone morphogenetic protein 4(fragment hBMP-4). Methods The hBMP-4 gene fragment was cut down from pCS2(+)/hBMP-4, cloned into the eukaryotic expressive vector pcDNA 3.1(+), then subcloned into pShuttle-CMV and transformed into the competent E. coli BJ5183/p by electroporation. The resulting recombinant plasmid pAdE/hBMP-4 was transformed into the packaging of thecell lines HEK293 to produce the replication-defective recombinant adenovirusescontaining the hBMP-4 gene. These replication-defective recombinant adinoviruses were transfected into HEK293 and HeLa cells. Then, total RNA and total protein were detected by RT-PCR and the Western-blot assay. Results The pAdE/hBMP-4 was confirmed by the restrictional endonuclease digestion. In HEK293 and HeLa cells, the specific transcription of the hBMP-4 gene was confirmed by RT-PCR, and the expression of the hBMP-4 protein was confirmed by theWestern-blot assay. Conclusion The replication-defective recombinant adinovirus expression vector containing the hBMP-4 gene can be constructed and expressed successfully, which has laid a foundation for the further research on the genetherapy of hBMP-4.
Objective To observe effects of the direct impaction onthe cell survival and the bone formation of the tissue engineered bone modified by the adenovirus mediated human bone morphogenetic protein 2 (Adv-hBMP2) gene and to verify the feasibility of the impacted grafting with it. Methods The marrow stromal cells (MSCs) were separated from the canine bone marrow and were cultured. MSCs were transfected with the Adv-hBMP2 gene and combined with the freeze-dried cancellous bone (FDB) to form the tissue engineered bone. Four days after the combination, the tissue engineered bone was impacted in a simulated impactor in vitro and implanted in the mouse. The cell survivals were evaluated with SEM 1 and 4 days after the combination, immediately after the impaction, and 1 and 4 days after the impaction, respectively. The bone formation and the allograft absorption were histologically evaluated respectively. Results There were multiple layers of the cells and much collagen on FDB before the impaction. Immediately after the impaction, most of the cells on the direct contact area disappearedand there was much debris on the section. Some of the cells died and separatedfrom the surface of FDB at 1 day, the number of the cells decreased but the collagen increased on the surface at 4 days. Histologically, only the fibrous tissue was found in FDB without the cells, the bone formation on FDB was even in distribution and mass in appearance before the impaction, but declined and was mainly on the periphery after the impaction in the AdvhBMP2 modified tissue-engineered bone. Conclusion The simulated impaction can decrease the cells survival and the bone formation of the AdvhBMP-2 modified tissue-engineered bone. The survival cells still function well.It is feasible to use the tissue engineered bone in the impaction graft.
Inherited retinal degenerations (IRD) are a group of diseases with high genetic heterogeneity and differences in inheritance patterns, age of onset and severity of visual dysfunction. It is one of the leading causes of blindness. In recent years, gene therapy becomes a popular research area in the treatment of genetic diseases due to the rapid development of gene diagnosis technology. Several clinical trials worldwide have proved the safety and effectiveness of gene therapies in IRD. Clinical application of adeno-associated virus -mediated gene therapies for Leber congenital amaurosis and choroideremia clinical trials indicate that patients' retinal functions were improved at different levels after treatment. There are a number of other IRD clinical trials ongoing currently, which bring new possibilities to treat IRD. This article reviews the pathogenesis of IRD, gene vectors and clinical trials in IRD.
Objective To study the effect of combined use of autologous micromorselized bone with bone morphogenetic protein(BMP) and type Ⅰ collagen graft on the treatment of segmental bone defects. Methods The bulk bone of rabbit iliac crest was ground into micromorselized bone, which was combined with BMP and type Ⅰ collagen. The model of 1.5 cm bone defect was established in the middle shaft of the radius. Fifty-six rabbits were assigned to four repairing methods: autologous micromorselized bone graft with BMP and type Ⅰ collagen, autologous micromorselized bone graft with type Ⅰ collagen, autologous micromorselized bone graft alone, and control group. The defect-repairing capability of each group was assessed by radiographic, histological, bone densitometry and biomechanical studies. Results X-ray manifested that at the end of 8 weeks after operation, the bone defect treated with autologous micromorselized bone graft with BMP and type Ⅰ collagen was repaired completely,and at the end of 12 weeks after operation the bone defect treated with autologous micromorselized bone and type Ⅰ collagen was cured completely, but the bonedefect treated with autologous micromorselized alone was completely repaired. No healing was found in the control group. In the bone densitometry detection, the material with BMP exhibited the best defectrepairing capability in terms of amount increased and quality of the new bone at the end of 8 weeksand 12 weeks. The group with BMP has the best mechanical strength of all groupsat the end of 12 weeks. Conclusion Autologous micromorselized bone graft with BMP/type Ⅰ collagen and autologous micromorselized bone graft with type Ⅰ collagen prove to be effective in repairing segmental bone defects. The autologousmicromorselized bone combined BMP and typeⅠcollagen is an excellent bone repairing material considering the satisfactory osteogenesis, osteoconduction, and osteoinduction seen in this method.
OBJECTIVE: To investigate the effects of bone morphogenetic protein (BMP) on the proliferation and collagen synthesis of skeletal muscle satellite cells. METHODS: Skeletal muscle satellite cells were harvested and cultured in vitro. The 0 ng/ml, 50 ng/ml, 100 ng/ml, 500 ng/ml, and 1000 ng/ml BMP were used to induce skeletal muscle satellite cells for 48 hours. Cell proliferation, rate of myotube formation and collagen-1 synthesis were measured. RESULTS: BMP promoted cell proliferation and reduced the rate of myotube formation. Collagen synthesis increased when skeletal muscle satellite cells were induced with more than 500 ng/ml BMP. And the higher the concentration of BMP was, the ber this effect became. CONCLUSION: BMP can enhance the proliferation of skeletal muscle satellite cells and change their differentiation from myoblasts to osteoblasts.
ObjectiveTo research the effect of recombinant adenovirus-bone morphogenetic protein 12 (Ad-BMP-12) transfection on the differentiation of peripheral blood mesenchymal stem cells (MSCs) into tendon/ligament cells.
MethodsPeripheral blood MSCs were isolated from New Zealand rabbits (3-4 months old) and cultured in vitro until passage 3. The recombinant adenoviral vector system was prepared using AdEasy system, then transfected into MSCs at passage 3 (transfected group); untransfected MSCs served as control (untransfected group). The morphological characteristics and growth of transfected cells were observed under inverted phase contrast microscope. The transfection efficiency and green fluorescent protein (GFP) expression were detected by flow cytometry (FCM) and fluorescence microscopy. After cultured for 14 days in vitro, the expressions of tendon/ligament-specific markers were determined by immunohistochemistry and real-time fluorescent quantitative PCR.
ResultsGFP expression could be observed in peripheral blood MSCs at 8 hours after transfection. At 24 hours after transfection, the cells had clear morphology and grew slowly under inverted phase contrast microscope and almost all expressed GFP at the same field under fluorescence microscopy. FCM analysis showed that the transfection efficiency of the transfected group was 99.57%, while it was 2.46% in the untransfected group. The immunohistochemistry showed that the expression of collagen type Ι gradually increased with culture time in vitro. Real-time fluorescent quantitative PCR results showed that the mRNA expressions of the tendon/ligament-specific genes (Tenomodulin, Tenascin-C, and Decorin) in the transfected group were significantly higher than those in untransfected group (0.061±0.013 vs. 0.004±0.002, t=-7.700, P=0.031; 0.029±0.008 vs. 0.003±0.001, t=-5.741, P=0.020; 0.679±0.067 vs. 0.142±0.024, t=-12.998, P=0.000).
ConclusionAd-BMP-12 can significantly promote differentiation of peripheral blood MSCs into tendon/ligament fibroblasts and enhance the expressions of tendon/ligament-specific phenotypic differentiation, which would provide the evidence for peripheral blood MSCs applied for tendon/ligament regeneration.
OBJECTIVE To improve the osteoinduction of coral and provide a perfect bone graft substitute for clinical bone defects. METHODS By combining coral with collagen and recombinant human bone morphogenetic protein-2(rhBMP-2), coral/collagen/rhBMP-2 composite was obtained. The composite was implanted into the back muscle pouches of mice, and coral/collagen or coral/rhBMP-2 were implanted as control. The osteoinduction of the composite was assessed by histology and image analysis system. RESULTS The chondrocyte differentiation and matrix formation were observed in local sites after one week, lamellar bone with bone marrow were formed after 4 weeks, and coral were absorbed partially. The quantity of osteoinduction was time-related and rhBMP-2 dose-related(P lt; 0.01). Coral/collagen and coral/rhBMP-2 implants did not show any bone or cartilage formation. CONCLUSION The coral/collagen/rhBMP-2 composite possesses a superior osteoinduction and will be a new type of bone substitute to be used in orthopedic and maxillofacial surgery.
Objective To observe the relationship between endothelial constitutive nitric oxide synthase (ecNOS) genetic polymorphism and diabetic retinopathy（DR）of non insulindependent diabetes mellitus (NIDDM) patients of the Han nationality.Methods A total of 166 patients who clinical diagnosed with NIDDM as case group, 85 cases of patients (cataract or fracture) and healthy subjects without diabetes, hypertension and kidney disease,over 40 years old of age and without consanguinity between each other were selected as normal control group. Case group were divided into non-DR (NDR) group, nonproliferative-DR (BDR) group and proliferativeDR (PDR) group according to the result of fundus fluorescein angiography. Case group and normal control group subjects all were Han nationality. DNA was extracted from peripheral venous blood; the fourth 27 base pairs (bp) repeat polymorphism of ecNOS gene by was measured by polymerase chain reaction (PCR). Results The 27 bp repeat sequences within the ecNOS gene present in the Han nationality,allele b repeat 5 times, alleles a repeat 4 times. PCR results showed that there are 2 alleles and 3 genotypes in normal control, NDR, BDR and PDR group. The frequency of genotype bb、ab、aa were 80%, 16.5%, 3.5% in normal subjects; 77.2％, 13.9%, 8.9％ in NDR group; 80.5％, 17.1%,2.4％ in BDR group;78.3％, 13%, 8.7％ in PDR group,respectively. The allele frequency (chi;2 =1.841) and gene frequency (chi;2=3.847) were not statistically significant (P＞0.5) in normal control,NDR,BDR and PDR group. Logistic regression analysis showed that there is no relation between DR and ecNOS duplicated gene polymorphism. Conclusions There is 27 bp repeated polymorphism in 4th intron of ecNOS gene, which may not be associated with the DR of NIDDM in the Han nationality.
Objective To investigate the mechanism of bone morphogenetic protein-4 (BMP4) in promoting the recovery of small intestinal mucosal barrier function during the recovery period of small intestine ischemia-reperfusion (I/R) injury. Methods Twenty-eight C57BL/6J male mice aged 6–8 weeks were randomly selected and assigned to small intestine I/R group (n=24) and sham operation (SO) group (n=4) by random number table method. Small intestine I/R injury models of 24 mice were established, then 4 mice were randomly selected at 6, 12, 24 and 48 h after I/R established modeling and killed to observe the morphological changes of small intestinal mucosa and detect the expression of BMP4 mRNA in the jejunal epithelial cells, the other 8 mice were allocated for the experimental observation at the recovery period of small intestine I/R injury (24 h after I/R was selected as the observation time point of recovery period of small intestine I/R injury according to the pre-experimental results). Twelve mice were randomly divided into I/R-24 h-BMP4 group (recombinant human BMP4 protein was injected intraperitoneally), I/R-24 h-NS (normal saline) group (NS was injected intraperitoneally), and I/R-24 h-blank group (did nothing), 4 mice in each group. Then the small intestinal transmembrane electrical impedance (TER) was measured by Ussing chamber. The expressions of BMP4 protein and tight junction proteins (occludin and ZO-1), Notch signaling pathway proteins (Notch1 and Jagged1), and Smad6 protein were detected by Western blot. Results At 24 h after I/R injury, the injuries of villous epithelium, edema, and a small part of villi were alleviated. The BMP4 mRNA expressions at 6, 12, 24 and 48 h after I/R injury in the small intestinal epithelial cells were increased as compared with the SO group. Compared with the I/R-24 h-NS group and the I/R-24 h-blank group, the TER was increased, and the expression levels of occludin, ZO-1, p-Smad6, Notch1, Jagged1 were increased in the I/R-24 h-BMP4 group. Conclusion From the preliminary results of this study, during recovery period of small intestine I/R injury, the expression of BMP4 in small intestinal epithelial cells is increased, permeability of jejunal mucosal barrier is increased, which might promote the recovery of small intestinal mucosal barrier function by activating the Notch signaling pathway (Notch1 and Jagged1), Smad classic signaling pathway, and promoting the increase of tight junction protein expression (occludin and ZO-1).
