MicroRNA-23b inhibits enterovirus 71 replication through downregulation of EV71 VPl protein.

Enterovirus 71 (EV71) is one of the causative pathogens of hand-foot-and-mouth disease and effective antiviral agents and vaccines against this virus have, to date, not been available. MicroRNAs (miRNAs) are a recently discovered class of RNAs with the function of post-transcriptional gene expression regulation. It has been demonstrated that miRNAs play important roles in the complicated interaction network between virus and host, while few studies have explored the role of miRNAs in EV71 infection. A recent study showed that hsa-miR-23b was downregulated significantly in cell-infected viruses. To address this issue, biological software miRanda was first used to predict possible target sites of miR-23b at EV71 gene sequence, then to confirm it by luciferase assay. miR-23b mimics were transfected to verify its effects on infection of EV71. These results suggest that miR-23b and upregulation of miR-23b inhibited the replication of EV71 by targeting at EV71 3'UTR conserved sequence. Taken together, miR-23b could inhibit EV71 replication through downregulation of EV71 VPl protein. These results may enhance our understanding on the prevention and treatment of hand-foot-and-mouth disease caused by EV71 infection.

[Prevalent characteristics in children with hand-foot-mouth disease in the Kunming area in 2010].

OBJECTIVE: To study the prevalent characteristics in children with hand-foot-mouth disease (HFMD) in the Kunming area in 2010. METHODS: The clinical data of 13286 outpatient and inpatient children with HFMD in Kunming Children's Hospital between January and December, 2010, including 8 death cases, 715 serious cases and 12563 non-serious cases, were retrospectively studied. RESULTS: Human enterovirus was detected in 8200 children (61.72%). Children infected with EV71 and CoxA16 accounted for 29.49% (2418/8200) and 53.21% (4363/8200), respectively. Seventy-five children (0.91%) were found to have a mixed infection of the two viruses. Other types of human enterovirus were detected in 1344 children (16.39%). There were significant differences in the total positive rate of human enterovirus in the four quarters of the year (P<0.01). The total positive rate in the second quarter represented the highest proportion (71.56%), and the number of patients was also highest, accounting for 52.94% of the total number of patients in the whole year. EV71 infection was common in the serious case group while CoxA16 was found to be the main pathogen in the non-serious case group. Serious cases were common in children under three years old. In the positive EV71 cases, the viral load of EV71 was not statistically different between the death cases, serious and non-serious cases. CONCLUSIONS: In 2010, children with HFMD in the Kunming area were mainly infected with CoxA16. Serious cases of HFMD were more common in those who were infected with EV71, and the majority of serious infections were suffered by children who were less than three years old. The viral load was not associated with disease severity. The highest morbidity rate was in the second quarter of the year.

[Biochemical screening and genetic diagnosis of thalassemia in children from Kunming].

OBJECTIVE: To investigate the types and frequency of gene mutations in children with thalassemia in Kunming, Yunan Province. METHODS: A biochemical screening for thalassemia was performed by testing RBC fragility, MCV and hemoglobin electrophoresis on 1338 children from Kunming, Yunnan Province. Genetic diagnosis was performed on the children with α-thalassemia by gap-PCR and on the children with ß-thalassemia by PCR-RDB. RESULTS: The positive rate of the biochemical screening for thalassemia was 11.36% (152 cases). The positive rate of genetic diagnosis was 8.59% (115 cases). Of the 115 cases, α-thalassemia was found in 43 cases, ß-thalassemia in 68 cases and α-combined-ß thalassemia in 4 cases.--SEA/αα accounted for 47%, -α4.2/αα accounted for 21%, and HbH disease accounted for 14%. Six genotypes were found in 68 cases of ß-thalassemia and the mutation frequency of ßE was the highest (32%), followed by CD41-42 (24%), CD17 (23%), IVS-II654 (10%), CD71-72 (10%), and -28 (1%). CONCLUSIONS: The frequency of gene mutations for thalassemia is high in children from Kunming, Yunnan Province. Premarital and prenatal screenings and genetic diagnosis for thalassemia should be carried out in this area.

Potential of CD34 in the regulation of symmetrical and asymmetrical divisions by hematopoietic progenitor cells.

The control of symmetric and asymmetric division in the hematopoietic stem/progenitor cell population is critically important for the regulation of blood cell production. Asymmetric divisions depend on cell polarization, which may be conferred by location and/or interaction with neighboring cells. In this study, we sought evidence for polarization in CD34+ cells, which interact by binding to one another. In these cells, surface molecules became redistributed by mechanisms that included transport by lipid rafts, and the interacting cells were able to communicate via gap junctions. These changes were accompanied by modulation of cell cycle regulating proteins (p16(Ink4a), p27(kip1), cyclins D, and the retinoblastoma pathway proteins) and a reduction in progenitor cell proliferation in vitro. These results are consistent with an increase in asymmetric cell division kinetics. Accordingly, we found that interaction between CD34+ cells influenced the plane of cell division in a way that suggests unequal sharing of Notch-1 between daughter cell progeny. We conclude that interaction between CD34+ cells may coordinate cell function and participate in the control of hematopoietic stem/progenitor cell division kinetics.