MicroRNA bmo-miR-31-5p inhibits apoptosis and promotes BmNPV proliferation by targeting the CYP9e2 gene of Bombyx mori.

BACKGROUND: Bombyx mori nuclear polyhedrosis virus (BmNPV), as a typical baculovirus, is the primary pathogen that infects the silkworm B. mori, a lepidopteran species. Owing to the high biological safety of BmNPV in infecting insects, it is commonly utilized as a biological insecticide for pest control. Apoptosis is important in the interaction between the host and pathogenic microorganisms. MicroRNAs (miRNAs) influence immune responses and promote stability of the immune system via apoptosis. Therefore, the study of apoptosis-related miRNA in silkworms during virus infection can not only provide support for standardizing the prevention and control of diseases and insect pests, but also reduce the economic losses to sericulture caused by the misuse of biological pesticides. RESULTS: Through transcriptome sequencing, we identified a miRNA, miR-31-5p, and demonstrated that it can inhibit apoptosis in silkworm cells and promote the proliferation of BmNPV in BmE-SWU1 cells. We identified a target gene of miR-31-5p, B. mori cytochrome P450 9e2 (BmCYP9e2), and demonstrated that it can promote apoptosis in silkworm cells and inhibit the proliferation of BmNPV. Moreover, we constructed transgenic silkworm strains with miR-31-5p knockout and confirmed that they can inhibit the proliferation of BmNPV. CONCLUSION: These data indicate that miR-31-5p may exert functions of inhibiting apoptosis and promoting virus proliferation by regulating BmCYP9e2. The findings demonstrate how miRNAs influence host cell apoptosis and how they are involved in the host immune system response to viruses, providing important insights into the applications of biological insecticides for pest control. © 2024 Society of Chemical Industry.

Bombyx moriSuppressor of Hairless is involved in the regulation of the silkworm cell cycle and endoreplication of the silk glands.

The Notch signaling pathway is important in cell cycle regulation and cell proliferation. The transcriptional repressor Suppressor of Hairless [Su(H)] is a molecular switch for downstream target genes of the Notch signaling pathway but the regulatory mechanism of the Su(H) gene in the cell cycle is unclear. We determined the function of the Notch signaling pathway and Bombyx mori Su(H) [BmSu(H)] in the regulation of the silkworm cell cycle. Inhibition of Notch signaling promoted the replication of DNA in silkworm gland cells and expression of the BmSu(H) gene was significantly reduced. Overexpression of the BmSu(H) gene inhibited DNA replication and cell proliferation of silkworm cells, whereas knockout of the BmSu(H) gene promoted DNA replication and cell proliferation. Knockout of the BmSu(H) in silkworms improved the efficiency of silk gland cell endoreplication and increased important economic traits. We demonstrated that BmSu(H) protein can directly bind to the promoters of BmCyclinA, BmCyclinE and BmCDK1 genes, inhibiting or promoting their transcription at the cell and individual level. This study identified molecular targets for genetic improvement of the silkworm and also provided insights into the regulatory mechanism of the cell cycle.

Family-Centered Care Improves Clinical Outcomes of Very-Low-Birth-Weight Infants: A Quasi-Experimental Study.

Background: Survival of very-low-birth-weight infants is improving in neonatology and family-centered-care might contribute to premature infants' clinical outcomes. Aim: To evaluate a family-centered care intervention on clinical outcomes of very-low-birth-weight infants. Methods: A quasi-experimental study was conducted in a Chinese NICU between June 2016 and June 2017. The intervention included parental education of basic care knowledge and skills followed by active participation in care for at least 4 h a day. A total of 319 very-low-birth-weight infants were recruited by convenience sampling; intervention group n = 156 and control group n = 163. Primary outcome measures were weight at discharge, length-of-stay, breastfeeding, nasal feeding, total parental nutrition, re-admission, hospital expenses. Secondary outcome measures were infant complications. Results: Infants' weight at discharge was higher in the interventions group (2,654 g vs. 2,325 g, p < 0.001). Nutritional outcomes improved significantly: breastfeeding rate 139 vs. 91, p < 0.001; days of total parental nutrition 25 d vs. 32 d, p < 0.001; gastric feeding days 23 d vs. 35 d, p < 0.001. Length-of-stay and hospital expenses did not differ between both groups. Improved infants' complications were bronchopulmonary dysplasia (32 vs. 51, p = 0.031), retinopathy of prematurity (between groups no/mild and moderate/severe, p = 0.003), necrotizing enterocolitis (6 vs. 18, p = 0.019), and re-admission rate (21 vs. 38, p = 0.023). No differences were observed in intraventricular hemorrhage and nosocomial infections. Conclusion: Very-low-birth-weight premature infants might experience improved clinical health outcomes when parents are present and caring from them. Family-centered care is as a beneficial care model for premature infants and should be recognized and implemented by NICUs where parents have currently limited access.

Mycoplasma pneumoniae pneumonia in hospitalized children diagnosed at acute stage by paired sera.

BACKGROUND: Mycoplasma pneumoniae (M. pneumoniae) is a frequent cause of respiratory tract infections. However, there is deficient knowledge about the clinical manifestations of M. pneumoniae infection. We described the clinical and laboratory findings of M. pneumoniae pneumonia in hospitalized children who were all diagnosed by a ≥ fourfold increase in antibody titer. METHODS: M. pneumoniae antibodies were routinely detected in children admitted with acute respiratory infection during a one-year period. The medical history was re-collected from children whose M. pneumoniae antibody titer increased ≥ fourfold at the bedside by a single person, and their frozen paired serum samples were measured again for the M. pneumoniae antibody titer. RESULTS: Of the 635 children whose sera were detected for the M. pneumoniae antibody, paired sera were obtained from 82 and 29.3% (24/82) showed a ≥ fourfold increase in antibody titer. There were 24 cases, nine boys and 15 girls, aged from two to 14 years, whose second serum samples were taken on day 9 at the earliest after symptom onset; the shortest interval was three days. All children presented with a high fever (≥ 38.5°C) and coughing. Twenty-one had no nasal obstruction or a runny nose, and five had mild headaches which all were associated with the high fever. The disease was comparatively severe if the peak temperature was > 39.5°C. All were diagnosed as having pneumonia through chest X-rays. Four had bilateral or multilobar involvement and their peak temperatures were all ≤ 39.5°C. None of the children had difficulty in breathing and all showed no signs of wheezing. CONCLUSIONS: The second serum sample could be taken on day 9 at the earliest after symptom onset meant that paired sera could be used for the clinical diagnosis of M. pneumoniae pneumonia in children at the acute stage. M. pneumoniae is a lower respiratory tract pathogen. Extrapulmonary complications were rare and minor in our study. High peak temperature (> 39.5°C) is correlated with the severity of M. pneumoniae pneumonia in children.