基质金属蛋白酶与转移性肾癌关系的研究进展

肿瘤侵袭转移是一个多步骤的极其复杂的过程,主要分为以下几步:(1)肿瘤细胞与基底膜表面的整合素受体及非整合素受体相结合,肿瘤细胞相互之间、肿瘤细胞和正常细胞之间发生脱离;

心室舒张功能不全及其治疗

舒张性心力衰竭的血流动力学改变以心室充盈阻力增加为特征,可由心内、外解剖结构异常,或心肌失活,细胞间基质异常和驰张生理过程紊乱造成,而心肌细胞内Ca++和生化改变则是引起舒张功能异常的生化机制。临床上应根据病人情况,给予改善舒张功能的药物治疗。 一、心室舒张功能不全的发病机制 1、心室肌肥厚:心肌梗塞后,非梗塞节段心肌出现局部肥厚,以代偿形成瘢痕组织的梗塞段的功能,从而形成左室的重建。肥厚的节段小血管心肌纤维比率降低更易发生缺血,导致舒张功能损害。实验表明,某些大面积心肌梗塞患者,即使不再发生心肌缺血,肥厚心肌也能转变成类似于容量负荷过重的充血性心力衰竭。 2、氧耗增加致缺血:心肌耗氧量超过冠状血管供氧或心肌间氧弥散量限度。

Mesenchymal stem cells： a new strategy for immunosuppression and tissue repair

Mesenchymal stem cells （MSCs） have great potential for treating various diseases, especially those related to tissue damage involving immune reactions. Various studies have demonstrated that MSCs are strongly immunosuppressive in vitro and in vivo. Our recent studies have shown that un-stimulated MSCs are indeed incapable of immunosuppression; they become potently immunosuppressive upon stimulation with the supernatant of activated lymphocytes, or with combinations of IFN-γ, with TNF-α, IL-1α or IL-1β. This observation revealed that under certain circumstances, inflammatory cytokines can actually become immunosuppressive. We showed that there is a species variation in the mechanisms of MSC-mediated immunosuppression： immunosuppression by cytokine-primed mouse MSCs is mediated by nitric oxide （NO）, whereas immunosuppression by cytokine-primed human MSCs is executed through indoleamine 2, 3-dioxygenase （IDO）. Additionally, upon stimulation with the inflammatory cytokines, both mouse and human MSCs secrete several leukocyte chemokines that apparently serve to attract immune cells into the proximity with MSCs, where NO or IDO is predicted to be most active. Therefore, immunosuppression by inflammatory cytokine-stimulated MSCs occurs via the concerted action of chemokines and immune-inhibitory NO or IDO produced by MSCs. Thus, our results provide novel information about the mechanisms of MSC-mediated immunosuppression and for better application of MSCs in treating tissue injuries induced by immune responses.

Epithelial-mesenchymal transition and cancermetastasis

Epithelial-mesenchymal transition （EMT） is initially considered as a physiological phenomenon during the embryogenesis of mammals, as well as a basic biological event maintaining the stability of the vital body. Recent researches indicated that EMT plays a critical role in various tumors progression, through which epithelial cancers invade and metastasize. The cell characteristics are changed during EMT, in which the cells lose cell-cell and cell-matrix interactions and apical polarity, reorganize their cytoskeleton, and become isolated, motile, as well as resistant to anoikis, then become spindle-shaped mesenchymal cells. This review lays emphasis on studying the cell morphogenesis, makers and molecular mechanism regulation about EMT, discussing the relationship between the EMT and the cancer development and metastasis.

Generation of Transgene-free Induced Pluripotent Stem Cells with Non-viral Methods

Induced pluripotent stem （iPS） cells were originally generated from mouse fibroblasts by enforced expression of Yamanaka factors （Oct3/4, Sox2, Klf4, and c-Myc）. The technique was quickly re- produced with human fibroblasts or mesenchymal stem cells. Although having been showed therapeutic po- tential in animal models of sickle ceil anemia and Parkinson＇s disease, iPS cells generated by viral methods do not suit all the clinical applications. Various non-viral methods have appeared in recent years for application of iPS cells in cell transplantation therapy. These methods mainly include DNA vector-based approaches, transfection of mRNA, and transduction of reprogramming proteins. This review summarized these non-viral methods and compare the advantages, disadvantages, efficiency, and safety of these methods.

Targeting of RhoE inhibits epithelial-mesenchymal transition during colorectal cancer cell migration

Objective Despite microRNA （miR-200b） being proved to promote the proliferation of colorectal cancer （CRC） cells, the relationship between miR-200b and epithelial-mesenchymal transition （EMT） of CRC cells remains poorly understood. The aim of the study was to investigate the relationship between miR-200b and EMT during CRC cell migration. Methods The effect of miR-200b on EMT-associated markers E-cadherin and vimentin was evaluated by western blot in CRC cells （SW620 and HT-29） by treatment with miR-200b mimics and inhibitors. A lucifer- ase reporter assay was employed to detect downstream targets of miR-200b. Transwell migration assays were used to detect CRC cell migration. Results Westem blots revealed that treatment with miR-200b mimics led to up-regulation of E-cadherin and down-regulation of vimentin, metalloproteinase （MMP）-9, and MMP-2, whereas treatment with miR- 200b inhibitor exhibited opposite effects on expression of E-cadherin and vimentin. Luciferase reporter assays demonstrated that RhoE （RND3） was targeted by miR-200b. Two predicted target sites of miR-200b were present in the 3＇-UTR of RhoE. Predicted target site 1 was from nucleotides 1584 to 1591, and site 2 was from nucleotides 1729 to 1735. RhoE knockdown cell lines were also established to investigate the impact of RhoE and miR-200b on EMT and cell migration. RhoE knockdown enhanced the effect of miR- 200b mimics, up-regulating E-cadherin and down-regulating vimentin. RhoE knockdown also inhibited cell migration. Furthermore, miR-200b mimic treatment further promoted the inhibitory effect of RhoE knock- down on cell migration.

EXPRESSION OF rhBMP-7 GENE IN TRANSDUCED BONE MARROW DERIVED STROMAL CELLS

OBJECTIVE: To explore the possibility of expression of exogenous gene in transduced bone marrow derived stromal cells (BMSCs). METHODS: The marker gene, pbLacZ, was transferred into cultured BMSCs and the expression of transduced gene by X-gal staining was examined. Then plasmid pcDNA3-rhBMP7 was delivered to cultured BMSCs. Through immunohistochemical staining and RT-PCR assay, the expression of rhBMP7 gene was detected. RESULTS: The exogenous gene could be expressed efficiently in transduced BMSCs. CONCLUSION: The present study provided a theoretical basis to gene therapy on the problems of bone and cartilage tissue.

Intravenous injection of mesenchymal stem cells is effective in treating liver fibrosis

AIM: To compare the influence of different transplant sites in bone marrow mesenchymal stem cell (MSC)-based therapy for liver fibrosis. METHODS: MSCs isolated from Sprague Dawley (SD) rats were induced into hepatocyte-like cells. Liver fibrosis in SD rats was induced with carbon tetrachloride. Following hepatocyte induction in vitro, 4',6-diamidino- 2-phenylindole (DAPI)-labeled MSCs were transplanted by intravenous, intrahepatic, and intraperitoneal injection. Histopathological staining, immunohistochemistry, and biochemical analysis were used to compare the morphological and functional liver regeneration among different MSC injection modalities. The expression differences of interleukins, growth factor, extracellular matrix, matrix metalloproteinases, and tissue inhibitor of metalloproteinase were examined by real-time reverse transcription-polymerase chain reaction (RT-PCR) andenzyme linked immunosorbent assay (ELISA). RESULTS: Four days after exposure to hepatocyte differentiation medium, MSCs that did not express hepatocyte markers could express α-fetoprotein, albumin, and cytokeratin 18. The results of histopathological staining, immunohistochemistry, and biochemical analysis indicated that intravenous injection is more effective at rescuing liver failure than other injection modalities. DAPI-labeled cells were found around liver lobules in all three injection site groups, but the intravenous group had the highest number of cells. PCR and ELISA analysis indicated that interleukin-10 (IL-10) was highest in the intravenous group, whereas il1β, il6, tnfα and tgfβ, which can be regulated by IL10 and are promoters of liver fibrosis, were significantly lower than in the other groups. CONCLUSION: MSC administration is able to protect against liver fibrosis. Intravenous injection is the most favorable treatment modality through promotion of IL10 expression.

Influence of Surface Geometry of Grating Substrate on Director in Nematic Liquid Crystal Cell

The director in nematic liquid crystal cell with a weak anchoring grating substrate and a strong anchoring planar substrate is relative to the coordinates x and z.The influence of the surface geometry of the grating substrate in the cell on the director profile is numerically simulated using the two-dimensional finite-difference iterative method under the condition of one elastic constant approximation and zero driven voltage.The deepness of groove and the cell gap affect the distribution of director.For the relatively shallow groove and the relatively thick cell gap,the director is only dependent on the coordinate z.For the relatively deep groove and the relatively thin cell gap,the director must be dependent on the two coordinates x and z because of the increased elastic strain energy induced by the grating surface.

Effects of mesenchymal stem cells transfected with human hepatocyte growth factor gene on healing of burn wounds

Objective： To explore the effects of bone marrow-derived mesenchymal stem cells （BMSCs）transfected with adenoviral vector carrying hepatocyte growth factor （HGF, Ad-HGF） on burn wound healing.Methods： BMSCs from male Wistar rats were separated and purified with Percoll separating medium by density gradient centrifugation and cultured with DMEM containing 20% fetal bovine serum （FBS）. Then BMSCs were transfected with Ad-HGF at the optimal gene transduction efficiency of 100 multiplicity of infection （MOI）. The efficiency of transfection and the expression of HGF in the suspension were detected by flow cytometry and enzyme linked immunosorbent assay （ELISA） respectively. Thirtytwo female rats were subjected to 90℃ water for 12 seconds to induce a partial thickness skin burn. The animals were randomly divided into mesenchymal stem cells （MSCs） treatment group （Group A）, Ad-HGF treatment group （Group B）,Ad-HGF-modified MSCs treatment group （Group C） and saline control group （Group D）. On days 3, 5, 7, 14 and 21 postburn, HE and Sirius red stain were performed to observe the burn wound healing and collagen content. The content of hydroxyproline in wounds was also detected.Transplanted cells and the expression of（sex-determining region Y） SRY gene were detected by in situ hybridization and polymerase chain reaction （PCR）, while the expression of HGF in wound tissues was detected by ELISA.Results： The result of flow cytometry showed that the transfection efficiency was 86.41% at 100 MOI. Compared with the control group, the content of HGF in the supernatant after transfection increased time-dependently and peaked at 48 h, showing significant differences at 24 h, 48 h,72 h and 96 h （P＜0.01 ）. Results of HE stain revealed that the range of re-epidermidalization in Group C was significantly larger than that in other groups in the first week. Three weeks postburn, the epidermis was significantly thicker in Group C than in other groups and the nails of dermis inserted into the derma of burn wounds. Sirius red stain showed that the content of collagen Ⅰ in Group C was much less compared with that in other groups 21 days postburn. In situ hybridization revealed an expression of SRY gene in burned female rats, consistent with the finding of PCR. Immunohistochemistry demonstrated the largest increase of HGF expression in Group C, whose contents of hydroxyproline,however, decreased on day 7 postburn. Compared with other groups, the content of HGF in the wounds of Group C increased obviously on day 14 after transfection （P＜0.05） and there was no significant difference among Groups A, B and D.Conclusion： Our study suggests that transplantation of MSCs modified with Ad-HGF has positive effects on the healing of burn wounds probably through differentiation and release of relevant cytokines.

Effect of the same mechanical loading on osteogenesis and osteoclastogenesis in vitro

Purpose： To investigate the influence of the same mechanical loading on osteogenesis and osteoclastogenesis in vitro. Methods： Primary osteoblasts, bone marrow-derived mesenchymal stem cells （BMSCs, cultured in osteoinductive medium） and RAW264.7 cells cultured in osteoclast inductive medium were all subjected to a 1000μstrain （μs） at 1 Hz cyclic mechanical stretch for 30 min （twice a day）. Results： After mechanical stimulation, the alkaline phosphatase （ALP） activity, osteocalcin protein level of the osteoblasts and BMSCs were all enhanced, and the mRNA levels of ALP and collagen type I increased. Additionally, extracellular-deposited calcium of both osteoblasts and BMSCs increased. At the same time, the activity of secreted tartrate-resistant acid phosphatase, the number of tartrate-resistant acid phosphatase-positive multinucleated cells, matrix metalloproteinase-9 protein levels of RAW264.7 cells and the extracellular calcium solvency all decreased. Conclusion： The results demonstrated that 1000 μs cyclic mechanical loading enhanced osteoblasts activity, promoted osteoblastic differentiation of BMSCs and restrained osteoclastogenesis of RAW264.7 cells in vitro.

Single cell atlas of developing mouse dental germs reveals populations of CD24^(+)and Plac8^(+)odontogenic cells

The spatiotemporal relationships in high-resolution during odontogenesis remain poorly understood.We report a cell lineage and atlas of developing mouse teeth.We performed a large-scale(92,688 cells)single cell RNA sequencing,tracing the cell trajectories during odontogenesis from embryonic days 10.5 to 16.5.Combined with an assay for transposase-accessible chromatin with high-throughput sequencing,our results suggest that mesenchymal cells show the specific transcriptome profiles to distinguish the tooth types.Subsequently,we identified key gene regulatory networks in teeth and bone formation and uncovered spatiotemporal patterns of odontogenic mesenchymal cells.CD24^(+)and Plac8^(+)cells from the mesenchyme at the bell stage were distributed in the upper half and preodontoblast layer of the dental papilla,respectively,which could individually induce nonodontogenic epithelia to form tooth-like structures.Specifically,the Plac8^(+)tissue we discovered is the smallest piece with the most homogenous cells that could induce tooth regeneration to date.Our work reveals previously unknown heterogeneity and spatiotemporal patterns of tooth germs that may lead to tooth regeneration for regenerative dentistry.

Combinatorial effects of NaomaiYihao Capsules(脑脉一号胶囊) and vascular endothelial growth factor gene-transfected bone marrow mesenchymal stem cells on angiogenesis in cerebral ischemic tis sues in rats

OBJECTIVE:To investigate the combinatorial effects of Naomai Yihao(NMYH) Capsules(脑脉一号胶囊) and vascular endothelial growth factor(VEGF) gene-transfected bone marrow mesenchymal stem cells(BMSCs) on angiogenesis in cerebral ischemic tissues in rats and the mechanism.METHOD:BMSCs were isolated and cultured from bone marrow by an adherence method.Then,BMSCs were transfected with the eukaryotic expression plasmid pEGFP-VEGF 165 by positive ionic liposome transfection.A rat model of middle cerebral artery occlusion(MCAO) was established.Rats were allocated to six groups:model,BMSC,VEGF gene-transfected BMSC transplantation(BMSC/VEGF),NMYH,combined NMYH and BMSC/VEGF(combined treatment group) and sham operation groups.The behavioral rating score(BRS) of rat and the expression of CD34 and VEGF in brain tis sue were measured by immunohistochemistry on days 7,14 and 21 after reperfusion.Angiogenesi was observed and evaluated with laser scanning confocal microscopy.RESULTS:The BRS of rats in NMYH,BMSC transplan tation and combined treatment groups was significantly lower than that of the model group(P< 0.001),with no significant difference between NMYH and transplantation groups(P=0.619).The expression of CD34 andVEGF in NMYH,transplanta tion and combined treatment groups increased(P< 0.001),with a significant difference between NMYH and transplantation groups(P<0.001).The blood vessel area in NMYH,transplantation and com bined treatment groups was significantly increased(P<0.05),without a significant difference between NMYH and transplantation groups(P=0.873).CONCLUSIONS:VEGF gene-transfected BMSCs im prove angiogenesis in the cerebral ischemic area NMYH Capsules promote angiogenesis in MCAO rats treated with BMSC transplantation,which show an improved BRS.The mechanism of angio genesis may be related to up-regulation ofVEGF ex pression.

Adhesion of bone marrow mesenchymal stem cells on porous titanium surfaces with strontium-doped hydroxyapatite coating

Objective: To determine the adhesion behavior of bone marrow mesenchymal stem cells(MSCs) on a titanium surface with a nanostructured strontium-doped hydroxyapatite(Sr-HA) coating. Methods: Sr-HA coatings were applied on roughened titanium surfaces using an electrochemical deposition method. Primary cultured rat MSCs were seeded onto Sr-HA-, HA-coated titanium, and roughened titanium surfaces, and they were then cultured for 1,6, and 24 h.3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay was used to determine the metabolic condition of the cells. Scanning electron microscopy(SEM) was used to observe the cell morphology. The cytoskeletal structure was analyzed using fluorescence actin staining to characterize cell adherence. Quantitative real-time reverse transcription polymerase chain reaction(RT-q PCR) was used to analyze the gene expression levels of FAK(focal adhesion kinase), vinculin, integrin β1, and integrin β3 after culturing for 24,48, and 72 h. Results: MSCs cultured on the Sr-HA surface showed better cell proliferation and viability. Improvement of cell adhesion and structural rearrangement of the cytoskeleton were observed on the Sr-HA surface. The gene expression of FAK, vinculin, integrin β1, and integrin β3 was also elevated on the Sr-HA surface. Conclusions: Cell viability, adhesion, cell morphology, and the cytoskeletal structure were all upregulated considerably by the titanium surface modified with a Sr-HA coating.

Application of human bone marrow-derived mesenchymal stem cells in the treatment of radiation-induced gastrointestinal syndrome

Nuclear accidents and terrorism present a serious threat for mass casualty.Accidental or intended radiation exposure leads to radiation-induced gastrointestinal(GI)syndrome.However,currently there are no approved medical countermeasures for GI syndrome.Thus,developing novel treatments for GI syndrome is urgent.Mesenchymal stem cells(MSCs)derived from bone marrow are a subset of multipotent adult somatic stem cells that have the ability to undergo self-renewal,proliferation and pluripotent differentiation.MSCs have advantages over other stem cells;they can be easily isolated from patients or donors,readily expanded ex vivo,and they possess reparative and immunomodulatory properties.Moreover,MSCs have been shown to be powerful tools in gene therapy and can be effectively transduced with vectors containing therapeutic genes.Therefore,the therapeutic potential of MSCs has been brought into the spotlight for the clinical treatment of GI syndrome.In this review,we discuss the possible role of MSCs in radiation-induced GI syndrome.