Identification of m6A regulator-mediated RNA methylation modification patterns and key immune-related genes involved in atrial fibrillation.

The role of m6A in the regulation of the immune microenvironment in atrial fibrillation (AF) remains unclear. This study systematically evaluated the RNA modification patterns mediated by differential m6A regulators in 62 AF samples, identified the pattern of immune cell infiltration in AF and identified several immune-related genes associated with AF. A total of six key differential m6A regulators between healthy subjects and AF patients were identified by the random forest classifier. Three distinct RNA modification patterns (m6A cluster-A, -B and -C) among AF samples were identified based on the expression of 6 key m6A regulators. Differential infiltrating immune cells and HALLMARKS signaling pathways between normal and AF samples as well as among samples with three distinct m6A modification patterns were identified. A total of 16 overlapping key genes were identified by weighted gene coexpression network analysis (WGCNA) combined with two machine learning methods. The expression levels of the NCF2 and HCST genes were different between controls and AF patient samples as well as among samples with the distinct m6A modification patterns. RT-qPCR also proved that the expression of NCF2 and HCST was significantly increased in AF patients compared with control participants. These results suggested that m6A modification plays a key role in the complexity and diversity of the immune microenvironment of AF. Immunotyping of patients with AF will help to develop more accurate immunotherapy strategies for those with a significant immune response. The NCF2 and HCST genes may be novel biomarkers for the accurate diagnosis and immunotherapy of AF.

CXCR4 protects bone marrow-derived endothelial progenitor cells against hypoxia through the PI3K/Akt signaling pathway.

The present study aimed to investigate the regulatory mechanism of chemokine (C-X-C motif) receptor 4 (CXCR4) on endothelial progenitor cells (EPCs) through the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway under hypoxic conditions. Mononuclear cells were isolated from the bone marrow (BM) of young Sprague-Dawley (SD) rats. Bone marrow-derived endothelial progenitor cells (BM-EPCs) were characterized by using Dil-labeled acetylated low-density lipoprotein (Dil-ac-LDL) and fluorescein isothiocyanate-labeled UEA (FITC-UEA-1). Phenotype identification of BM-EPCs was based on red cytoplasm and green cytomembrane. Flow cytometry was employed to examine the markers CD14, CD34, and KDR. Expression level of the EPC-specific surface marker CD14 was found to be negative, while the expression level of CD34 and KDR was positive. In addition, CXCR4 was stably overexpressed in BM-EPCs after transfection with adenovirus-CXCR4. Cell proliferation, migration and apoptosis abilities were measured through the application of CCK-8, followed by Transwell and flow cytometry assays. The expression level of CXCR4, PI3K and Akt was determined by reverse transcription-quantitative PCR and western blotting assays. Functional experiments demonstrated that hypoxia inhibited BM-EPC proliferation and migration, while accelerating BM-EPC apoptosis. Additionally, CXCR4 was found to promote proliferation and migration, and suppress apoptosis in BM-EPCs with or without hypoxia treatment. Evidence also demonstrated that CXCR4 markedly upregulated the expression levels of PI3K and Akt. Furthermore, PI3K inhibitor (LY294002) and CXCR4 inhibitor (AMD3100) effectively inhibited the proliferation, migration and resistance to apoptosis of CXCR4-mediated BM-EPCs under hypoxic conditions.

Downregulated microRNA-330 suppresses left ventricular remodeling via the TGF-ß1/Smad3 signaling pathway by targeting SRY in mice with myocardial ischemia-reperfusion injury.

microRNAs (miRs) are essential in the development of heart failure. The aim of this study is to investigate the effect of microRNA-330 (miR-330) on left ventricular remodeling via the TGF-ß1/Smad3 signaling pathway by targeting the sex-determining region Y (SRY) in mice with myocardial ischemia-reperfusion injury (MIRI). Differentially expressed gene (DEG) in myocardial ischemia-reperfusion (IR) was screened out and the miR that targeted the DEG was also predicted and verified. A model of MIRI was established to detect the expression of miR-330, SRY, transforming growth factor-ß (TGF-ß1), and Sekelsky mothers against dpp3 (Smad3). To further investigate the role of miR-330 in MIRI with the involvement of SRY and TGF-ß1/Smad3 signaling pathway, the modeled mice were treated with different mimic, inhibitor, or small interfering RNA (siRNA) to observe the changes of the related gene expression, as well as the myocardial infarction size and volume of myocardial collagen. SRY was screened out and verified as a target gene of miR-330. The MIRI mice showed enlarged myocardial infarction size, increased volume of myocardial collagen, increased expression of miR-330, TGF-ß1 and Smad3, while decreased the expression of SRY. The MIRI mice treated with miR-330 inhibitor showed decreased myocardial infarction size, the volume of myocardial collagen, and expression of TGF-ß1 and Smad3 but promoted expression of SRY. Our findings demonstrated that downregulated miR-330 could suppress left ventricular remodeling to inhibit the activation of the TGF-ß1/Smad3 signaling pathway via negatively targeting of SRY in mice with MIRI. This can be a potential target in the strategy to attenuate patient suffering.

Increased expression of serum gelsolin in patients with osteosarcoma.

BACKGROUND: Identification of potential serum biomarkers of osteosarcoma to aid in its early diagnosis and in the discovery of possible therapeutic targets is an area of increasing interest. METHODS: Two-dimensional difference-in-gel electrophoresis was used to assess multiple serum samples in patients with osteosarcoma. In addition, differential expression of protein biomarkers was characterized in osteosarcoma serum by using matrix-assisted desorption/ionization time-of-flight mass spectrometry coupled with database interrogation. Serum samples from four individuals with osteosarcoma and four age- and sex-matched healthy control subjects were compared. RESULTS: Fifty-eight significant protein spot features in the osteosarcoma sera were found. These spot features were excised, digested with trypsin, and analyzed with mass spectrometry. Gelsolin was down-regulated only in osteosarcoma. Furthermore, Western blotting and enzyme linked immunosorbent assay (ELISA) confirmed decreased levels of gelsolin in the osteosarcoma serum samples. CONCLUSIONS: These results indicated that gelsolin might have great potential as a biomarker of osteosarcoma and as a potential target for gene therapy.

[Construction and expression of recombinant adeno-associated virus vector containing HSV1-TK gene].

OBJECTIVE: To construct the recombinant adeno-associated virus(rAAV) vector plasmid pSNAV2.0-TK containing HSV1-TK gene, to produce recombinant adeno-associated virus rAAV2/HSV1-TK, and to detect the integration and expression of HSV1-TK gene in lens epithelial cells transfected by rAAV2/HSV1-TK, and to provide foundation for gene therapy of posterior capsular opacification. METHODS: The recombinant vector plasmid constructed by gene recombinant technology was analyzed by PCR and restriction enzyme digestion. The cell strain BHK-21/TK was screened by G418 after the plasmid was transfected into BHK-21 cells,with the helper virus HSV1-rc/UL2 to produce the recombinant virus rAAV2/HSV1-TK. The purity of rAAV2/HSV1-TK was detected by SDS-PAGE and HPLC, and the titre of rAAV2/HSV1-TK was observed by dot blot hybridization. The HSV1-TK gene in lens epithelial cells transfected by rAAV2/HSV-TK was investigated by PCR and RT-PCR. RESULTS: The recombinant plasmid proved successful by PCR and restriction enzyme digestion. The recombinant virus rAAV2/HSV1-TK was produced successfully and its titre was 1 x 10(12) v.g./mL by dot blot hybridization. The HSV1-TK gene was integrated and expressed in lens epithelial cells. CONCLUSION: The recombinant adeno-associated virus vector plasmid containing HSV1-TK gene is successfully constructed, and high titre recombinant adeno-associated virus (rAAV2/HSV1-TK) is obtained. The HSV1-TK gene in lens epithelial cells is expressed after being transfected by rAAV2/HSV1-TK.

[Construction of rAAV2-GPIIb/IIIa vector and test of its expression and function in vitro].

This study was aimed to explore the possibility of rAAV2 vector-mediating gene therapy for Glanzmann' s thrombasthenia. The rAAV2-GPIIb/IIIa vector was constructed. The GPIIb/IIIa gene expression in mammal cell were examined by different methods, such as: detection of mRNA expression in BHK-21 cells after 24 hours of infection (MOI = 1 x 10(5) v.g/cell) was performed by RT-PCR; the relation between MOI and quantity of GPII6/IIIa gene expression was detected by FACS after 48 hours of infection; GPIIb/IIIa protein expression in BHK-21 cells after 48 hours of infection (MOI = 10(5) v x g/cell) was assayed by Western blot, GPIIb/IIIa protein expression on cell surface was detected by immunofluorescence, and the biological function of expressing product was determined by PAC-1 conjunct experiments. The results showed that GPIIb/IIIa gene expression in mRNA level could be detected in BHK-21 cells after 24 hours of infection at MOI = 1 x 10(5) v x g/cell and the GPIIb/IIIa gene expression in protein level could be detected in BHK-21 cells after 48 hours of infection at MOI = 1 x 10(5) v x g/cell. In certain range, quantity of GPIIb/IIIa gene expression increased with MOI, but overdose of MOI decreased quantity of GPIIb/IIIa gene expression. Activated product of GPIIb/IIIa gene expression could combined with PAC-I, and possesed normal biological function. In conclusion, rAAV2 vactor can effectively mediate GPIIb and GPIIIa gene expressing in mammal cells, and the products of these genes exhibit biological function. This result may provide a basis for application of rAAV2 vector in Glanzmann's thrombasthenia gene therapy in furture.

[Construction of a large human scFv library against SARS virus].

AIM: To construct a large human scFv library against SARS virus by using in vivo recombination. METHODS: Total RNA was isolated from the lymphocytes of 6 patients recovered from SARS. mRNA was isolated and reverse transcribed into cDNA. The V(H) and V(L) fragments were amplified from the cDNA and then assembled into scFv genes. The scFv genes were amplified and ligated into phagemid pDAN5. The primary library was constructed by transforming the recombinant phagemid into E.coli TG1. The secondary library was generated by in vivo recombination in E.coli BS1365 following the infection of BS1365 by primary library phages. RESULTS: A primary library of 3x10(9) and a second library of 3x10(11) were constructed. CONCLUSION: A large human scFv library against SARS virus with good diversity was constructed, which may be used for screening antibodies to SARS virus antigens.

[Expression of coagulation factor IX in human CD34 + hematopoietic stem cells by adeno-associated virus 2].

OBJECTIVE: To investigate the expression of human coagulation factor IX (hFIX) gene in human umbilical cord blood (CB) CD34+ cells which was transfected with recombinant adeno-associated virus 2 (rAAV-2). METHOD: The CD34+ cells were transfected with rAAV-2/hFIX and cultured for 21 days for inducing differentiation into myeloid, erythroid and megakaryocytes, respectively. The expression of hFIX was studied at mRNA, protein and biological activity levels. The cytotoxicity of rAAV-2 to CD34+ cells was evaluated by cell proliferation, cell vitality, CD antigen expressions and CFU yields. RESULTS: The hFIX mRNA was expressed in the cultured cells which was verified by RT-PCR and DNA sequencing. An elevated level of hFIX expression and biological activities were detected with a maximum amount of 14.10 ng/10(6) cell x 24 h. During the period of 21 day culture, the cell vitality, cell proliferation, CD antigen expression and CFU yields between the transfected and un-transfected groups had no difference(P > 0.05). CONCLUSION: The human CB CD34+ cells are able to produce functional hFIX after transduction by rAAV-2/hFIX. The cell proliferation and differentiation capacities of the host CD34+ cells were not affected by rAAV-2.

[Preparation of rAAV2/hFIX and experimentally application to gene therapy for hemophilia B].

OBJECTIVE: To prepare the rAAV2/hFIX and evaluate the efficiency of the preparation on gene therapy of hemophilia B model mice. METHODS: The rAAV-2/hFIX was prepared by "one helper virus-one vector cell line" strategy and transfected both BHK-21 and C2C12 cells in vitro. The hFIX antigen level in cell culture supernatant was assayed. The rAAV-2/hFIX was injected into muscles of hemophilia B model mice and assayed the serum hFIX levels, hFIX clotting activity, bleeding time, 5 min bleeding volume. RESULTS: The hFIX antigen could be detected from 24 h till 120 h after BHK-21 and C2C12 cells were transfected with highest levels at 24 h reaching (51.0 +/- 6.5) ng/10(5) cells and (68.0 +/- 7.2) ng/10(5) cells, respectively. The rAAV2/hFIX injected mice could efficiently express hFIX and peaked at three weeks after injection, then slowly decreased but low level hFIX antigen was still detectable till 10 weeks after injection. There were significant differences between the high, middle and low dose groups of rAAV2/hFIX and the control group (P < 0.01), the plasma FIX clotting activities in the model mice were improved remarkably, bleeding time was greatly shortened and bleeding in 5 min was decreased. The hFIX expression level and FIX clotting activity of the high dose of rAAV2/hFIX group (1.6 x 10(13) v.g./kg) reached about (387.0 +/- 12.5) ng/ml plasma in contrast with the normal levels of (30.0 +/- 5.5)% at the third week after injection. No rAAV2 vector DNA was detected in the organs except for injected muscle tissue. CONCLUSION: The rAAV2/hFIX transfected BHK-21 and C2C12 cells could efficiently express hFIX antigen and was of therapeutic effects for the hemophilia B model mice by intramuscularly injection.The results provide the basis for clinical trial of rAAV2 gene therapy for hemophilia B.

[Transduction efficiency of recombinant adeno-associated virus 2 in human umbilical cord blood CD34+ hematopoietic stem/progenitor cells].

To investigate the transduction efficiency of recombinant adeno-associated virus 2 (rAAV-2) in human umbilical cord blood CD34(+) hematopoietic stem/progenitor cells, the CD34(+) cells sorted by the method of magnetic cell sorting from human cord blood were infected with the rAAV-2 expressing the green fluorescent protein (GFP) gene. After transduction for 19 hours, the expression of GFP was detected under fluorescence microscope. The results showed that 43% CD34(+) cells expressed the GFP gene at a multiplicity of infection of 2 x 10(5). It is concluded that the rAAV-2 can transduce human cord blood CD34(+) hematopoietic stem/progenitor cells efficiently.

[Construction of a tRNAVal promoter plasmid expressing shRNAs in mammalian cells which mediates RNA interference].

OBJECTIVE: Constructing a plasmid containing tRNAVal promoter to express shRNA which mediates RNA interference. METHODS: A tRNAVal gene was amplified from human genomic DNA by PCR and replaced the last several bases of 3' end by a linker. The tRNAVal promoter after artificial mutation followed a shRNA sequence to luciferase was cloned into pUC18, Puc-tRNAVal, lucRi Cotransfected with pMAMneoLuc into BHK-21 cell to detect the effect of luciferase expression. RESULTS: pUC-tRNAVallucRi suppressed the luciferase expression from pMAMneoLuc by 97.9%-9.5%. CONCLUSION: The results showed that the tRNAVal shRNA plasmid could efficiently suppress luciferase expression in BHK-21.