Effects of SDF-1/CXCR4 signal pathway blockade by AMD3100 on the adhesion of leukemia cells to osteoblast niche and the drug resistance of leukemia cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the blocking effect of CXCR4 inhibitor AMD3100 on the adhesion of leukemia cells to osteoblast niche, and the reversal of multidrug resistance in leukemia cells.</p><p><b>METHODS</b>Mesenchymal stem cells (MSCs) from leukemia patients were planted on the bio-derived bone scaffolds and then induced into osteoblasts to establish the bio-osteoblast niche. The levels of SDF-1were tested with ELISA. The leukemia cell line MV4-11 cells with FLT3-ITD mutation were inoculated into the bio-osteoblast niche to build a three-dimensional co- culture system. The expression level of CXCR4, adhesion and apoptosis rates of leukemia cells were observed by flow cytometry after incubation with AMD3100 and Ara-C for 24 h and 48 h.</p><p><b>RESULTS</b>(1)The supernatant levels of SDF-1 in cultured osteoblast were (304 ± 18), (410 ± 28) and (396 ± 16) pg/ml on 7 th, 14 th and 21 th day, respectively. It reached the highest on 14 th day. The expression level of CXCR4 in cultured MV4-11 cells was (72 ± 16)%. (2)Adhesion rate of MV4-11 cells to osteoblast niche was (40.1 ± 8.1)% after AMD3100 treatment for 24 h, while that of control group was (65.6 ± 12.1)% (P<0.05). (3)The apoptosis rate of MV4-11 cells incubated with AMD3100 for 24 h was (5.6 ± 0.8)%, while that of control group was (2.5 ± 0.5)%. The apoptosis rates of AMD3100-induced MV4-11 cells were (10.0 ± 2.4)%, (17.8 ± 2.3)% and (25.1 ± 2.4)% after treatment with Ara-C at 0.02, 0.20, 2.00 mg/ml respectively and they were (6.7 ± 1.0)%, (10.3 ± 1.5)%, (16.2 ± 3.1)% respectively in AMD3100-noninduced control group, the difference was significant (P<0.05).</p><p><b>CONCLUSION</b>AMD3100 can block the interaction between osteoblasts niches and leukemia cells, and play an important role in the reversal of multidrug resistance in leukemia cells.</p>

Research progress in antidotes of nerve agents in the USA / 军事医学

Nerve agent not only inhibit acetylcholinesterase ( AChE) at an early stage, but also induce prolonged and progressive neuroinflammation and delayed neurodegeneration.Recently, the US National Institute of Health ( NIH) has sponsored some major programs of toxic mechanisms and treatment of nerve agents, which aims at the development of quick and effective treatment to acute intoxication and delayed effect.The experimentally effective new antidotes mainly include AChE-targeting drugs, broad-spectrum reactivators and scavengers, antiinflamatory and nerve protection drugs.

miR-34a partially reverses inhibition of CEES-exposed keratinocytes migration via ERK1/2 pathway / 军事医学

Objective To explore the effect of 2-chloroethyl ethyl sulfide(CEES) poisoning on keratinocyte migration and the regulatory role of microRNA(miR)-34a.Methods MTS was used to detect the viability of cells exposed to CEES in order to select an appropriate dose of CEES exposure in this in vitro model.The protein level of keratin 5 and keratin 10 was detected to assess cell differentiation status .Scratch assay was applied to evaluate cell migration ,and miR-34a silencing in keratinocytes was achieved by transfecting chemically synthesized miR-34a specific miRNA inhibitor.t-ERK1/2 and p-ERK1/2 levels closely related to cell migration were detected using Western blotting .Results An in vitro CEES exposure model of keratinocytes was established at the optimal concentration of 0.5 mmol/L CEES in the viability test , and this dose was chosen to evaluate cell migration changes .The migration of cells was significantly inhibited 24 h after CEES exposure , accompanied by no changes in morphology and keratin 5/10 levels.Silencing of miR-34a significantly increased the migration of cells exposed to CEES , which could be blocked by adding 5 μmol/L U0126 , an ERK1/2 phosphorylation selective inhibitor.Conclusion Silencing of miR-34a can significantly increase keratinocyte migration and partially reverse the inhibition of CEES-caused migration , which could be mediated by ERK 1/2 pathway activation .

Effect of glucose concentrations on energy metabolism in 16 HBE cells exposed to CEES / 军事医学

Objective To compare the changes in energy metabolism in 2-chloroethyl ethryl sulfide(CEES)-poisoned bronchial epithelial cell 16HBE cultured in media at different glucose concentrations .Methods Bronchial epithelial cell 16HBE was cultured in high (4.5 mg/ml) or low (1.1 mg/ml) glucose medium and exposed to a sulfur mustard simulant CEES of 0.2, 0.5, 1.0 mmol/L.Cell growth and cytotoxicity were tested using MTS .ATP, ADP and AMP were detected by HPLC and the value of ATP/ADP, total adenine nucleotides ( TAN) and energy charge ( EC) was subsequently calculat-ed.Mitochondrial oxidative phosphorylation-related proteins, COX-10 and ISCU, were detected using Western blotting . Rhodamine 123 was applied to detect the mitochondrial membrane potential using flow cytometry .Results Low glucose accelerated the growth and energy metabolism of 16HBE cells in regular culture , and the contens of ADP , TAN, COX-10 and ISCU in low glucose group were significantly higher than those in high glucose group .CEES exposure (≥0.5 mmol/L) significantly affected cell viability in both high and low glucose groups , with significant difference between the two groups exposed to 1.0 mmol/L CEES.In high glucose group, 24 h after 0.5 or 1.0 mmol/L CEES exposure, the contents of ATP, ADP and TAN were significantly increased , while ATP/ADP and EC decreased .In low glucose group , ADP, AMP and TAN significantly decreased, while ATP/ADP and EC increased 24 h after 1.0 mmol/L CEES exposure.The mi-tochondrial membrane potential (MMP) also changed differently after 0.5 mmol/L CEES exposure.MMP in high glucose group marginally increased at 3 h, and significantly increased at 8-12 h (P<0.05), and returned to normal at 24 h. MMP in low glucose group showed a transient decrease at 5 h (P<0.01), and back to normal at 8 h.The protein levels of COX-10 and ISCU were significantly increased in high glucose group 24 h after 0.5-1.0 mmol/L CEES exposure , but sig-nificantly decreased in low one 24 h after 1.0 mmol/L CEES exposure .Conclusion When 16HBE is cultured at a high or low glucose concentration , the cell growth, stress responses and energy metabolism including MMP , COX-10, ISCU and ATP production are in different status before or after CEES exposure .High glucose could protect against CEES exposure .

Soluble expression and purification of human alpha-defensin-5 in Escherichia coli / 生物工程学报

DNA fragment containing human alpha-defensin 5 mature peptide (mHD-5) coding sequence with biased codons of E. coli was amplified by PCR, which was subsequently cloned into the plasmid pMAL-p2x in order to create pMAL-p2x-mHD-5 expression vector. The plasmid pMAL-p2x-mHD-5 was transferred into engineered strain BL21(DE3) to express heterogeneous fusion protein (MBP-mHD-5). The soluble MBP-mHD-5 targeted protein inducible expressed by IPTG was accounted for about 30% under optimized conditions. The recombinant mHD-5 (rmHD-5) peptide was successfully purified through a separation process including affinity chromatography, Factor Xa digestion and ion exchange chromatography. The bioactivity of rmHD-5 was examined by bacteria-inhibition tests in liquid culture. The growth of E. coli ATCC25922 was dramatically suppressed with an inhibition rate of 90%, with the presence of 62.5 microg/mL rmHD-5 in the media. These results indicate that the strategy of soluble expression of fusion protein in E. coli can be a useful and practical way to produce bioactive defensins.

Platelet-derived Growth Factors and Tissue Repair / 中国康复理论与实践

@#Platelet-derived growth factors (PDGFs) are a member of family of glycoprotein dimers (Mr 27000～35000) that exert potent mitogenic and chemotactic activities toward cells of mesenchymal origin. The PDGFs possess a myriad of critical roles in embryonic development,cellular differentiation and response to tissue damage. It is one of the growth factors,which appear early during the process of wound healing. Especially,PDGFs can effectively promote the healing of some chronic refractory wounds,such as diabetes mellitus ulcer,chronic venous ulcer,bedsore,radioactivity ulcer,etc..

Morphological study on the growth of human amniotic membrane loaded with porcine bone marrow-derived mesenchymal stem cells / 中国组织工程研究

BACKGROUND: Human amniotic membrane (HAM) contains various ingredents such as collagen, glycoprotein,proteoglycan, integrin and laminated body, and so on, and expresses many kinds of growth factors and mRNA-associated proteins. And these ingredents can supply abundant nutriments for cellular proliferation and differentiation, and benefit cells to grow and propagate. Whether or not HAM can load porcine bone marrow-derived mesenchymal stem cells (BMSCs) to well grow on it deserves to be further investigated.OBJECTIVE: To set up a method of tissue engineering of human amniotic membrane loading porcine BMSCs and observe the morphological characteristics of growth and proliferation of BMSCs seeded on HAM.DESIGN: Randomized controlled observation.SETTING: State Key Laboratory of Trauma, Burn and Combined Injury, General Institute of Combined Injuries, Academy of Preventive Medicine, Third Military Medical University of Chinese PLA.MATERIALS: This experiment was carried out in the State Key Laboratory of Trauma, Burn and Combined Injury,General Institute of Combined Injuries, Academy of Preventive Medicine, Third Military Medical University of Chinese PLA between January and November 2003. Three Guizhou minipigs of either gender, aged 2 to 3 months, weighing from 6 to 8 kg, were provided by the Experimental Animal Center, Third Military Medical University of Chinese PLA. Main reagent:ISCOVE'S modified DULBECCO'S medium (IMDM) culture medium (Hyclone, USA); high-quality fetal bovine serum PAA (Germany); haematoxylin (China); Eosin B (Sigma, USA) and OCT embedding medium (USA). Main instruments: BX51 stereoscopic fluorescence microscope (Olympus, JaPan); IX70 inverted fluorescence microscope (Olympus, Japan);cryostat (2700-Frigcut, Germany); myeloid puncture needle (Jiangsu); superclean bench (Sujing Bloc Antai Company);CO2 constant-temperature incubator (QUEUE, USA).METHODS: HAM was prepared as previously described. The BMSCs of Guizhou minipigs isolated and cultured according to method described previously were primarily cultured and passaged, then they were inoculated to the stromal surface of HAM at different densities (0.84×105 cells/cm2,1.54×105 cells/cm2,2.75×105 cells/cm2); The growth and proliferation of BMSCs of different densities were observed under an inverted microscope and scanning electron microscope; BMSCs of the second or the third passages were inoculated on HAM held with tissue-holding device at a density of 1.54×105 cells/cm2, and they were cultured for 18 days at most. The HAM was daily rolled, sliced and stained by HE for observing the growth of BMSCs loaded on HAM under the light, scanning and transmission electron microscopes.MAIN OUTCOME MEASURES: The growth of BMSCs on HAM was examined at different densities and different time points.RESULTS: ① Comparison of growths of BMSCs promoted by different densities of HAM: BMSCs,which were planted on HAM at the density of 0.84×105 cells/cm2 were irregular and scattered under an invert microscope. Distances between BMSCs were biggish. BMSCs seeded on HAM at the density of 1.54×105 cells/cm2 were regular in arrangement and moderate in density, with clear cell outline and good cell activity before 24 hours, and seeded at the density of 2.75×105 cells/cm2 were congested with many nonattached cells and the longer the growing time of the cells was, the more the cellular debris were observed. BMSCs,which were planted on HAM at the density of 0.84×105 cells/cm2 under the scanning electron microscope, scatted on HAM presented in shapes of irregular, long, thin and flat polygon. Their membrane protuberances presented in shapes of thick and thin, and the distances between cells were biggish. BMSCs,which were planted on HAM at the density of 1.54×105 cells/cm2 have similar appearance of their bodies and membrane protuberances, and the membrane protuberances were more compared with the BMSCs planted at the density of 0.84×105 cells/cm2. Their membrane protuberances intercrossed each other, and the margin of some BMSCs overlapped each other. BMSCs planted at the density of 2.75×105 cells/cm2, arraved on HAM crowdedly and overlappedly with many debris. Their membrane protuberances were not obviously. The margin of some BMSCs was overlapped.② Comparisonof growths of BMSCs promoted by HAM at different time points: Under the inverted microscope, the BMSCs adhered quickly to HAM after being incubated for about 30 minutes. All of BMSCs adhered to HAM within 24 hours, and formed monolayer on it within 48 hours, and grew densely on HAM after being cultured for 4 to18 days. Under the light and electron microscopes, HE results revealed that BMSCs adhered tightly and grew on HAM in different arrays, such as emitting, whirlpool or parallel,and their nuclei located in middle, dense in staining, were big and clear. The shapes of BMSCs were comparatively consistent on HAM. HAM loaded with BMSCs grew 4 days, and BMSCs covered HAM completely. The densities of BMSCs on HAM were suitable, and their bodies were large, and presented irregular, long,thin and flat polygon under the scanning electron microscope. The margin of some BMSCs overlapped each other. The protuberances of cellular membrane of BMSCs were abundant in the shapes of thick and thin. Some protuberances intercrossed each other in the shape of net. BMSCs adhered tightly to HAM through these protuberances. HAM loading BMSCs grow 4 days; most of BMSCs grew on HAM in double layers with the shapes of cambiform under the transmission electron microscope, Their nucleoli were clear. The protuberances of cellular membrane of BMSCs, which situated at two sides of nuclei and overlapped each other, were long. Most of chromatins of BMSCs were autosome.Abundant organell such as rough endoplasmic reticulum (RER),mitochondria could be observed in BMSCs.CONCLUSION:HAM is able to promote the proliferation of BMSCs significantly. BMSCs may be cultured on HAM ex vivo.HAM is a good carrier of BMSCs.

Construction and identification of recombinant adenovirus expressing hPDGF-A and hBD-2 / 第三军医大学学报

Objective To further determine their possible synergistic effect on accelerating wound healing, adenovirus vector containing recombinant human hPDGF-A and hBD2 genes was constructed and the expression of exogenous genes in transformed mesenchymal stem cells derived from rat bone marrow was observed. Methods By putting IRES in the middle of hPDGF-A and hBD2, these two genes were expected to be expressed individually. The shuttle vector was named as pAdTrack-hPDGF-A-IRES2-hBD2, which homologously recombinated with Adeasy-1 in BJ5183 cells and formed the mammalian expression vector pAdeasy-hPDGF-A-IRES2-hBD2. Furthermore, the recombinant vector was packaged in 293 cells into infectious recombinant adenovirus, which were used to infect BMSCs. The expression of hPDGF-A and hBD2 in BMSCs was detected by RT-PCR. Results We successfully constructed recombinant adenovirus vector that simultaneously expressed hPDGF-A and hBD2. The expressions of hPDGF-A and hBD2 were confirmed by RT-PCR on transformed BMSCs. Conclusion The established BMSCs that overexpressed hPDGF-A and hBD2 provide a new strategy of combining cell therapy and gene therapy to promote wound healing, especially the chronic one.

Feasibility of MSCs mobilization by G-CSF and its prosthetic effect in traumatic brain injury / 第三军医大学学报

Objective To explore the feasibility of mobilization circulating MSCs by G-CSF and observe the repairing effect of G-CSF mobilization in severe mouse traumatic brain injury(TBI) model.Methods MSCs-derived bone marrow and peripheral blood(PB) were cultured and its CFU-F were counted after mobilization by G-CSF.At 2,24,48,96,120,144,192,264,336 h after severe TBI in mice was establish,the neurobehavior of mice was measured by neurological examination and motor functional test,and mortality rate and pathologic changes were analyzed.Results MSCs-derived PB were successfully cultured.The CFU-F of mobilization group increased significantly than that of control group(P

Repairing effect of sarcoblasts from mesenchymal stem cells induced by MyoD transfection on muscle injury / 解放军医学杂志

Objective To observe the repairing effects of myoblasts from mesenchymal stem cells induced by MyoD transfection on muscle injury, and to explore its mechanism. Methods One hundred and sixty male SCID mice were randomly assigned into 4 groups [normal group, control group with injury, implantation with mesenchymal stem cells (MSCs) group, and implantation with myoblasts group]. MSCs were transfected by pIRES2-EGFP-MyoD and differentiated into myoblasts. Myoblasts and MSCs were injected respectively into the muscular tissue injuried by cardiotoxin. The repairing effect in injuried muscles, which were injected with myoblasts and MSCs, was observed 1, 2, 4 and 6 weeks after the injection. Results The muscular tissue injury model was successfully reproduced. Both MSCs and myoblasts showed obvious repairing effects on the injured muscular tissue, and the strength of muscular tissue in myoblasts group was stronger than that in MSCs group. Western blot assay showed that MyoD expression in myoblasts group was much higher than that in both MSCs and control groups, the expressions of JNK1 and ERK2 were up-regulated in myoblasts group, and the p38 expression was down regulated significantly in the 1st week, but no significant difference was found when compared with those of the normal group at the 6th week. Conclusion Myoblasts transdifferentiated from MSCs induced by MyoD can repair the injuried muscular tissue effectively. JNK1, p38 and ERK2 play important roles in the repairing process.

Effect of nordihydroguaiaretic acid on expressions of VEGF and its receptor KDR in vitro / 第三军医大学学报

Objective　To explore the effect of nordihydroguaiaretic acid (NDGA) on the expressions of vascular endothelial growth factor (VEGF) and its receptor, kinase-inserted domain containing receptor(KDR) and the possible mechanism. Methods　The expression of VEGF in human malignant glioma cell line SHG-44 and that of KDR in human umbilical vein endothelial cell (HUVEC) line ECV-304 were observed 1～3 d after NDGA treatment with immunohistochemistry, in situ hybridization and image analysis. Results　The expression of VEGF was declined at protein or mRNA levels in SHG-44 cells after treated with 100 μmol/L NDGA for 1 to 3 d. The expression of KDR in endothelial cells with 100 μmol/L NDGA treatment for 1 to 3 d was decreased too, in a more obvious way compared with the decline of VEGF expression in SHG-44 cells. Conclusion　The results suggest that NDGA inhibits the expression of VEGF in glioma cells as well as that of VEGF receptor KDR in endothelial cells, which may be the important molecular mechanism of anti-angiogenesis of NDGA.

Experimental study on preventive and therapeutic effec ts of 5 radioprotectants on combined radiation-burn injured mice / 第三军医大学学报

Objective　To compare the irradiation-protective and inter-synergestic effects of E838,WR-2721, Rubia cordifolia, cystamin e hydrochloride and ethinyl estradiol on radiation and combined radiation-burn injury. Methods　Above-mentioned drugs were given to the mice i ntraperitoneally, or intragastrcally, then, the mortality and the average surviv al d for 30 d were observed before and after the administration of the drug s. Results　①When drugs were before injury , the survival rate and the average survival d of the radiation and combined radiation-burn injured mice were increased obviously with the best effect in E838 and WR-2721. ②When drugs were given after injury, E838 and R. cordifolia also kept the effect. ③Combined appling WR-2721（pre) and E838（post）displayed a significant syner gistic reaction. Conclusion　E838 and WR-2721 are more e ffective than the others in the prevention of radiation.

Prospects of Research on Bone Marrow Mesenchymal Stem Cells / 中国实验血液学杂志

Besides hematopoietic stem cells, bone marrow also contains another type of stem cells called mesenchymal stem cells (MSCs). With different induced conditions, MSCs have the ability to differentiate into a variety of nonhematopoietic tissue cells, including osteoblasts, chondroblast, adipocytes, myoblasts, astrocytes, and so on. MSCs can be readily obtained from bone marrow by their adhesion to plastic and expansion in culture. Also they can be genetically engineered by transduced target genes. MSCs may be the farget cells for both cell therapy and gene therapy for diseases derived from many different nonhematopoietic tissues.

Early functional changes of the heart after radiation, burn or combined radiation-burn injury in rats / 第三军医大学学报

The early functional changes of the heart after radiation, burn or combined radiation-burn injury were studied with an isolated working heart preparation of rats. The animals were randomized into the control group (C), the burn injury group (B) inflicted with 30% TB-SA full thickness burns from a 5 kw bromine-tungsten lamp, the radiation injury group (R) inflicted with total body irradiation of 6 Gy from a "Co source and the combined radiation-burn injury group (RB) receiving both of the injuries. No treatment was administered after injury. Left ventricular systolic pressure (LVSP). maximum of LV pressure development ( ? dp/ dtmax), heart rate (HR), cardiac output (CO), coronary flow (CF), aortic pressure (A.P) and ratio of dry/wet myocardial weight (Rw) of the perfused isolated heart were determined in the 1st, 3rd, 8th, 16th and 24th hour after injury. It was found that LVSP, ?dp/dtmax, CO and AP were decreased in RB especially in the 8th hour after injury ( P

Effects of hPDGF-A/hBD_2 genes transfection on rat bone marrow mesenchymal stem cells / 第三军医大学学报

Objective To study the biological characteristics of platelet-derived growth factor A and human beta defensin 2 (hPDGF-A/hBD2) gene-modified rat bone marrow mesenchymal stem cells (BMSCs). Methods By using liposome transfection technique, recombinant adenovirus vector expressing hPDGF-A/hBD2 (Adv-hPDGF-A-IRES-hBD2) labeled with GFP was transfected into 293T cells for virus packaging and amplification. BMSCs were isolated, cultured and infected by adenovirus-containing supernatant. The exogenous gene-modified BMSCs were comprehensively studied on their biological features, in terms of morphology, cell growth curve, cell cycle, and adipogenic, osteogenic and myogenic differentiation ability. Results hPDGF-A-IRES-hBD2 gene-modified BMSCs did not show obvious changes in cell viability, proliferation, cell cycle distribution or cell differentiation. Conclusion BMSCs were not only good carriers for exogenous hPDGF-A and hBD2 genes but also seed cells for cell therapy even after hPDGF-A/hBD2 modification.