Abstract We first described the 2019 novel coronavirus infection in 10 children occurring in areas other than Wuhan. The coronavirus diseases in children are usually mild and epidemiological exposure is a key clue to recognize pediatric case. Prolonged virus shedding is observed in respiratory tract and feces at the convalescent stage.

MicroRNAs (miRNAs) are small yet versatile gene tuners that regulate a variety of cellular processes, including cell growth and proliferation. The aim of this study was to explore how miR‐448‐5p affects airway remodeling and transforming growth factor‐β1 (TGF‐β1)‐stimulated epithelial‐mesenchymal transition (EMT) by targeting Sine oculis homeobox homolog 1 (Six1) in asthma. Asthmatic mice models with airway remodeling were induced with ovalbumin solution. MiRNA expression was evaluated using quantitative real‐time polymerase chain reaction. Transfection studies of bronchial epithelial cells were performed to determine the target genes. A luciferase reporter assay system was applied to identify whether Six1 is a target gene of miR‐448‐5p. In the current study, we found that miR‐448‐5p was dramatically decreased in lung tissues of asthmatic mice and TGF‐β1‐stimulated bronchial epithelial cells. In addition, the decreased level of miR‐448‐5p was closely associated with the increased expression of Six1. Overexpression of miR‐448‐5p decreased Six1 expression and, in turn, suppressed TGF‐β1‐mediated EMT and fibrosis. Next, we predicted that Six1 was a potential target gene of miR‐448‐5p and demonstrated that miR‐448‐5p could directly target Six1. An SiRNA targeting Six1 was sufficient to suppress TGF‐β1‐induced EMT and fibrosis in 16HBE cells. Furthermore, the overexpression of Six1 partially reversed the protective effect of miR‐448‐5p on TGF‐β1‐mediated EMT and fibrosis in bronchial epithelial cells. Taken together, the miR‐448‐5p/TGF‐β1/Six1 link may play roles in the progression of EMT and pulmonary fibrosis in asthma.

Airway remodeling is characterized by airway wall thickening, subepithelial fibrosis, increased smooth muscle mass, angiogenesis and an increase in mucous glands, which may lead to a chronic and obstinate asthma with pulmonary function depression. In the present study, we observed substantially thickened lung tissue with extensive fibrosis in ovalbumin-sensitized mice, which was interrelated with transforming growth factor-β1 (TGF-β1) expression in bronchoalveolar lavage fluid. In vitro experiments further demonstrated that TGF-β1 resulted in epithelial-mesenchymal transition (EMT) in bronchial epithelial cells, which was characterized by the expected decrease in E-cadherin expression and the increase in vimentin and α-smooth muscle actin expression, as well as the associated increase in Snail expression at mRNA and protein levels. Furthermore, the downregulation of Snail by small interfering RNA (siRNA) attenuated the TGF-β1‑induced EMT-like phenotype. Of note, a significantly increased synthesis of fibronectin was observed following TGF-β1 treatment, which further supported the hypothesis that EMT is a pivotal factor in peribronchial fibrosis. In combination, the results indicated that myofibroblasts deriving from bronchial epithelial cells via EMT may contribute to peribronchial fibrosis and that Snail may be an important factor in this phenomenon.

Airway remodeling is characterized by airway wall thickening, subepithelial fibrosis, increased smooth muscle mass, angiogenesis and increased mucous glands, which can lead to a chronic and obstinate asthma with pulmonary function depression. In the present study, we investigated whether the astragalus extract inhibits airway remodeling in a mouse asthma model and observed the effects of astragalus extract on the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway in ovalbumin-sensitized mice. Mice were sensitized and challenged by ovalbumin to establish a model of asthma. Treatments included the astragalus extract and budesonide. Lung tissues were obtained for hematoxylin and eosin staining and Periodic acid-Schiff staining after the final ovalbumin challenge. Levels of TGF-β1 were assessed by immunohistology and ELISA, levels of TGF-β1 mRNA were measured by RT-PCR, and levels of P-Smad2/3 and T-Smad2/3 were assessed by western blotting. Astragalus extract and budesonide reduced allergen-induced increases in the thickness of bronchial airway and mucous gland hypertrophy, goblet cell hyperplasia and collagen deposition. Levels of lung TGF-β1, TGF-β1 mRNA and P-Smad2/3 were significantly reduced in mice treated with astragalus extract and budesonide. Astragalus extract improved asthma airway remodeling by inhibiting the expression of the TGF-β1/Smad signaling pathway, and may be a potential drug for the treatment of patients with a severe asthma airway.

The aim of the present study was to investigate the expression levels and clinical significance of Toll-like receptor (TLR) 3 and 4 in peripheral blood mononuclear cells (PBMCs) collected from children with Henoch-Schönlein purpura (HSP) nephritis. The randomized controlled trial was conducted between August 2011 and March 2013, and 105 children with a clinical diagnosis of HSP were enrolled in the study. According to the 24-h urinary protein measurements and the presence of renal damage, the 105 cases were divided into groups A, B and C as follows: Group A, children with HSP but without renal damage; group B, children with HSP nephritis but without proteinuria; group C, children with HSP nephritis and proteinuria. A total of 30 healthy children were enrolled in the normal control group (group N). The primary endpoints were the detection of TLR3 and 4 mRNA and protein expression levels in PBMCs by flow cytometry and quantitative polymerase chain reaction. The mRNA and protein expression levels of TLR4 in the PBMCs were significantly higher in groups A, B and C when compared with group N. In addition, the mRNA and protein expression levels of TLR4 in group C were much higher when compared with groups A and B. A positive correlation was identified between TLR4 protein expression and 24-h urinary protein levels in group C. The expression levels of TLR3 did not significantly differ among the groups. Protein and mRNA expression levels of TLR4 in PBMCs significantly increased and exhibited a positive correlation with urinary protein excretion. These results indicate that aberrant activation of TLR4 may be relevant to the development of HSP nephritis.

<b><i>Background:</i></b> Transforming growth factor-β1 (TGF-β1)-in­duced proliferation of airway smooth muscle cells plays critical roles in the development of airway remodeling<i>.</i> Six1 (sine oculis homeobox homolog 1) has been demonstrated to be involved in airway inflammation and remodeling in asthmatic mice. <b><i>Objectives:</i></b> The aim of this work was to investigate the potential role of miR-204-5p in the proliferation and extracellular matrix (ECM) production of airway smooth muscle cells in asthma. <b><i>Methods:</i></b> Real-time PCR was used to measure the expression of miR-204-5p in asthmatic airway smooth muscle cells. Cell viability and apoptosis were detected to evaluate the effect of miR-204-5p on airway smooth muscle cells. Dual-luciferase reporter experiments were applied to identify the target genes of miR-204-5p. <b><i>Results:</i></b> MiR-204-5p was downregulated notably in asthmatic airway smooth muscle cells as well as cells stimulated with TGF-β1. Overexpression of miR-204-5p markedly suppressed the TGF-β1-induced proliferation of airway smooth muscle cells and the deposition of ECM, whereas the inhibition of miR-204-5p significantly enhanced the proliferation of airway smooth muscle cells and upregulated the level of fibronectin and collagen III. Furthermore, subsequent analyses demonstrated that Six1 was a direct target of miR-204-5p, and Western blot further indicated that miR-204-5p negatively regulated the expression of Six1. Most importantly, the restoration of Six1 expression reversed the inhibitory effect of miR-204-5p on TGF-β1-induced proliferation and ECM production. <b><i>Conclusions:</i></b> MiR-204-5p inhibits TGF-β1-in­duced proliferation and ECM production of airway smooth muscle cells by regulating Six1, identifying a potential therapeutic target for preventing airway remodeling in asthma.

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The aim of the present study was to investigate the association between genetic variants in 17 tagSNPs of the NLRP3 gene and the susceptibility to primary gouty arthritis. A genotype-phenotype analysis of 480 primary gout and 480 control patients was performed. Samples from all the patients were collected from The Affiliated Hospital of Medical College (Qingdao, China). Seventeen tagSNPs of the NLRP3 gene were amplified using polymerase chain reaction (PCR) and MassARRAY technology was used for single nucleotide polymorphism (SNP) genotyping. The genetic frequency of rs7512998 was significantly different between the gout and control patients (P<0.05), whereas no significant differences were identified for the remaining SNPs. The 17 SNPs conformed to the Hardy-Weinberg equilibrium (HWE) in the control group (P>0.05). The haplotype association among the 17 SNPs of the NLRP3 gene indicated that no individual SNP was significantly associated with primary gouty arthritis. CTATCAGCGCCCAGTGC was the most common haplotype in the case and control groups, with a frequency of 0.224 and 0.243, respectively. However, the odds ratios (ORs) of the 8 haplotypes were not identified to be significantly associated with gouty arthritis (P>0.05 for all the 8 haplotypes). To the best of our knowledge, this is the first study to investigate the association between SNPs of the NLRP3 gene and the risk of primary gouty arthritis, although no significant association was identified. Further clinical studies and functional analysis are required to explore the potential associations between NLRP3 gene polymorphisms and the risk of primary gouty arthritis.