miR-125b regulates osteogenic differentiation of human bone marrow mesenchymal stem cells by targeting Smad4 / 中南大学学报(医学版)

OBJECTIVE@#To investigate whether miR-125b regulates the osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs) by modulating Smad4, a predicted target in silicon.@*METHODS@#Smad4 3'-UTR-luciferase vector was constructed and dual-luciferase reporter gene assay was employed to examine the effect of miR-125b on luciferase activity. MSCs were isolated and cultured from human bone marrow, and then transfected with miR-125b mimics followed by induction of osteogenic differentiation. qRT-PCR and Western blot were used to detect the expressions of Smad4 mRNA and protein. MSCs were induced into the osteoblasts after transfecting with Smad4 siRNA, and the effect of Smad4 downregulation on osteogenic differentiation was observed by AKP activity and RUNX2 mRNA levels.@*RESULTS@#miR-216b bound Smad4 3'-UTR and inhibited the luciferase activity (P<0.05). Smad4 mRNA and protein expressions were significantly down-regulated in the MSCs induced into osteogenic differentiation when miR-125b was overexpressed. Downregulation of Smad4 suppressed the AKP activity and RUNX2 mRNA expression, indicating that Smad4 siRNA simulated at least in part the function of miR-125b as the regulator of MSCs osteogenic differentiation.@*CONCLUSION@#miR-125b can suppress MSCs osteogenic differentiation by directly targeting Smad4.

Prevalence of influenza A and variation of H1N1 influenza A virus in Shanghai area in 2009 / 中华传染病杂志

Objective To understand epidemic characteristics of human influenza A and the genetic and antigenic variations of H1N1 influenza A isolates in Shanghai area in 2009. Methods Throat swabs were collected from patients with influenza-like illness in the sentinel surveillance clinic in Shanghai area in 2009, then inoculated in Madin-Darby canine kidney (MDCK) cell lines. The types of influenza were identified by direct immunofluorescence assay (DIF) and the subtypes were determined by reverse transcriptase-polymerase chain reaction (RT-PCR). Segments of hemagglutinin (HA) and neuraminidase (NA) genes of some 2009 H1N1 influenza A isolates were amplified and sequenced. HA and NA gene mutations of 2009 H1N1 influenza A isolates were analyzed. Results Seasonal H1N1 and H3N2 influenza A viruses co-circulated during the spring of 2009 in Shanghai area. Seasonal H3N2 began to co-circulate with 2009 H1N1 in August (the 32nd week) and finally2009 H1N1 became dominate since the 40th week. The phylogenetic tree of 2009 H1N1 HA segment revealed that the isolates from different regions and months were interspersed with each other, but all were clustered into one branch which closed to strains in Spain, Russia, Denmark and other European countries. Mutations were found in some HA amino acid sites, but none of them was in the antigenic determinant region. No change was observed in the 274 NA amino acid residues which were related to the drug resistance to oseltamivir. PB2 protein analysis showed that the 627 and 701 amino acid residues were glutamic acid and aspartic acid respectively, which were the same encoded amino acid with avian flu PB2 protein. Conclusions Seasonal H1N1 and H3N2 co-circulated in the spring of 2009, then both 2009 H1N1 and seasonal H3N2 were prevalent in Summer and Autumn, and 2009 H1N1 finally became dominate in Autumn. Compared to early 2009 H1N1 strains, variations are detected in H1N1 influenza A viruses, but none of them has epidemiological influence, and viruses still show high affinity with human and low-pathogenic characteristics.

The sensitivity of cytopathic effect caused by influenza viruses in cultured Madin-Darby canine kidney cells / 中华传染病杂志

Objective To understand the sensitivity of cytopathogenic effect (CPE) in MadinDarby canine kidney cells(MDCK) that cultured influenza A pharyngeal swab specimens of patients for one,two and three passages. Methods Influenza A pharyngeal swab specimens of patients were inoculated in MDCK for three blind passages. The presence of CPE of every passage was observed by inverted microscope. Results Of the 279 influenza A pharyngeal swab specimens of patients tested by colloidal gold, the presence of CPE in MDCK for one,two and three passages was 65.9%(184/279),91.4%(255/279) and 96.4%(269/279), respectively. Two hundred and seventy-one of 279specimens were identified as influenza A by multiplex reverse transcription-polymerase chain reaction (RT-PCR). Conclusion The positive separation rate can reach more than 95% by inoculating influenza A pharyngeal swab specimens of patients in MDCK for three blind passages.

Analysis of levels of antibodies against influenza A virus of population in Shanghai during 2009 / 中华传染病杂志

Objective To know the levels of antibodies against influenza A virus subtypes H1 and H3 of population in Shanghai during 2009, and the detection of antibodies against avian influenza virus subtypes H5 and H9 in population which contacts with avian. Methods The serological survey of the antibodies against influenza A viruses subtypes H1, H3, H5 and H9 in 356 close contacts with avian (professional population) and 332 general subjects (general population) at various age groups were carried out using hemagglutinin inhibit (HI) test. Results The positive rates of antibodies against influenza virus A/Brisbane/59/2007 (H1N1) in general population and professional population were 82.8% (275/332) and 73.9% (263/356), respectively; those of A/Brisbane/10/2007 (H3N2)were 50.6% (168/332) and 54.8% (195/356), respectively. The positive rate of antibodies against influenza virus A/Brisbane/59/2007 (H1N1 )was significantly higher than that of influenza A viruses subtype H3, which was consistent with etiological survey of influenza virus in Shanghai during 2008.The positive rates of antibodies against influenza A virus subtype H5 in professional population and general population were 4.2% (15/356) and 0.3% (1/332), respectively; those of influenza A virus subtype H9 were 34.6% (123/356) and 2.4% (8/332), respectively. The positive rates of antibodies against influenza virus A/Brisbane/59/2007 (H1N1 ) and A/Brisbane/10/2007 (H3N2) in age groups of 6 months-5 years and ≥60 years were lower than other age groups. Conclusions The immune protective response against seasonal influenza A subtype H1 and H3 of population in Shanghai is high,while those of children and the elders were low. The levels of antibodies against influenza A viruses subtype H5 and H9 in professinal population present obviously ascending trend, which indicates that the etiological and serological survey of influenza virus in this population should be enhanced.

Etiological study of hand,foot and mouth disease among children in Shanghai and neighbor areAfls in 2008 / 中华传染病杂志

Objective To investigate the distribution and genetic characteristic of etiological agents among children with hand,foot and mouth disease(HFMD)in Shanghai and neighbor areas in 2008.Methods Throat swabs were collected from the inpatients with HFMD from May to June 2008 in Pediatrics Hospital affiliated to Fudan University,Shanghai,and Deqing,Zhejiang Province.Cerebral spinal fluid(CSF)from some patients were collected as well.Vero,MRC-5 and RD ceils were used to isolate the possible pathogens by observing cytopathic effect(CPE).Enterovirus genus,Coxsaekie virus group A type 16(CoxA16)and enterovirus type 71(EV71)were detected by reverse transcriptase-polymerase chain reaction(RT-PCR),and finally identified by sequencing.Results A total of 107 swabs and 22 CSF samples were collected from all 100 inpatients.Swabs of 50 children caused CPE observed.Among them,enteroviruses accounted for 74.0%(37/50),which including 26 (52.0%)of EV71,10(20%)of CoxAl6 and 1(2.0%)of CoxB3,and 13(26.0%)of other pathogens.All the 26 EV71 strains were similar with the isolates from Zhejiang Province and Fuyang,Anhui Province in 2008,which belonged tO genotype Cl all the 10 CoxAl6 strains belonged to genetic lineages C.Conclusions The causative agents of HFMD are complicated.CoxA16 and EV71 are predominant among children with HFMD in Shanghai and neighbor areas in 2008,while the pathogens of some patients are still unknown.