Clinical and molecular epidemiologic features of enterovirus D68 infection in children with acute lower respiratory tract infection in China.

Acute flaccid paralysis (AFP) associated with enterovirus D68 (EV-D68) infection has attracted much attention since an outbreak in the USA in 2014. Notably, EV-D68 was detected in a child with AFP for the first time in China in 2018. In a multicentre study from May 2017 to December 2019, we monitored EV-D68 infections in hospitalized children with acute lower respiratory tract infection (ALRTI) in China. Out of 3,071 samples collected from patients with ALRTI, ten were positive for EV-D68. All patients presented with mild diseases with no neurological symptoms or signs. Phylogenetic analysis based on the VP1 gene showed that all EV-D68 sequences obtained in this study belonged to subclade B3 and were close to sequences of EV-D68 strains obtained from patients with AFP in the USA. Four EV-D68 strains were isolated, and their complete genome sequences were determined. These sequences did not show any evidence of recombination events. To assess their neurotropism, the isolates were used to infect the "neuronal-like" cell line SH-SY5Y, and resulted in a cytopathic effect. We further analysed the structure and sites that may be associated with neurovirulence, including the stem-loop structure in the untranslated region (3'UTR) and identified amino acid substitutions (M291T, V341A, T860N, D927N, S1108G, and R2005K) in the coding region and specific nucleotides (127T, 262C, and 339T) in the 5' UTR. In conclusion, EV-D68 infection was detected in a small number of children with ALRTI in China from 2017 to 2019. Disease symptoms in these children were relatively mild with no neurological complications, and all EV-D68 sequences belonged to subclade B3.

A multicentre study on the incidence of respiratory viruses in children with community-acquired pneumonia requiring hospitalization in the setting of the zero-COVID policy in China.

BACKGROUND: Stringent nonpharmaceutical interventions (NPIs) have been implemented worldwide to combat the COVID-19 pandemic, and the circulation and seasonality of common respiratory viruses have subsequently changed. There have been few multicentre studies or comparisons of the prevalence of respiratory viruses accounting for community-acquired pneumonia (CAP) in hospitalized children between the pre-COVID period and the period after community and school reopening in the setting of the zero-COVID policy. METHODS: We included 1543 children with CAP who required hospitalization from November 1, 2020 to April 30, 2021 (period 1), and 629 children with the same conditions from November 1, 2018, to April 30, 2019 (period 2), in our study. All respiratory samples from these patients were screened for six respiratory viruses (respiratory syncytial virus [RSV], adenovirus [ADV], influenza A virus [Flu A], influenza B virus [Flu B], parainfluenza virus type 1 [PIV1], and parainfluenza virus type 3 [PIV3]) using a multiplex real-time PCR assay. RESULTS AND CONCLUSIONS: The median ages of the enrolled patients at the time of diagnosis were 1.5 years and 1.0 years for period 1 and period 2, respectively. In period 1, viral pathogens were detected in 50.3% (776/1543) of the enrolled patients. The most frequently identified viral pathogen was RSV (35.9%, 554/1543), followed by PIV3 (9.6%, 148/1543), PIV1 (3.6%, 56/1543), ADV (3.4%, 52/1543), Flu A (1.0%, 16/1543), and Flu B (0.8%, 13/1543). The total detection rates of these six viruses in the peak season of CAP were at the pre-COVID level. The prevalence of Flu A decreased dramatically, and circulation activity was low compared to pre-COVID levels, while the incidence of PIV3 increased significantly. There were no significant differences in the detection rates of RSV, ADV, Flu B, and PIV1 between the two periods. Our results showed that respiratory viruses accounted for CAP in hospitalized children at pre-COVID levels as communities and schools reopened within the zero-COVID policy, although the prevalence aetiology spectrum varied.

Molecular Mechanism of the ß-Lactamase Mediated ß-Lactam Antibiotic Resistance of Pseudomonas aeruginosa Isolated From a Chinese Teaching Hospital.

Pseudomonas aeruginosa can cause infections in the blood, lungs (pneumonia), or other parts of the body after surgery. To investigate the molecular characteristics of ß-lactam antibiotic resistance of P. aeruginosa isolated from a hospital population between 2015 and 2017, in this study, the antimicrobial susceptibility and the resistance gene profile of the bacteria were determined. The Pulsed-field gel electrophoresis (PFGE) was used to characterize the clonal relatedness and sequencing and comparative genomic analysis were performed to analyze the structure of the resistance gene-related sequences. As a result, of the 260 P. aeruginosa strains analyzed, the resistance rates for 6 ß-lactam antibiotics ranged from 4.6 to 9.6%. A total of 7 genotypes of 44 ß-lactamase genes were identified in 23 isolates (8.9%, 23/260). Four transconjugants from different donors carrying bla CARB-3 exhibited a phenotype of reduced susceptibility to piperacillin-tazobactam, ceftazidime, and cefepime, and 2 transconjugants harboring bla IMP-45 exhibited a phenotype of reduced susceptibility to carbapenems. bla CARB positive isolates (n = 12) presented six PFGE patterns, designated groups A to F. Two bla genes (bla IMP-45 and bla OXA-1) in PA1609 related to a class 1 integron (intI1-bla IMP-45- bla OXA-1-aac(6')-Ib7-catB3-qacE∆1-sul1) were encoded on a plasmid (pPA1609-475), while the bla CARB-3 gene of PA1616 also related to a class 1 integron was located on the chromosome. The results suggest that ß-lactam antibiotic resistance and clonal dissemination exist in this hospital population. It indicates the necessity for molecular surveillance in tracking ß-lactamase-producing strains and emphasizes the need for epidemiological monitoring.

Colistin Resistance and Molecular Characterization of the Genomes of mcr-1-Positive Escherichia coli Clinical Isolates.

Research on resistance against polymyxins induced by the mcr-1 gene is gaining interest. In this study, using agar dilution method, polymerase chain reaction, and comparative genomic analysis, we investigated the colistin resistance mechanism of clinical E. coli isolates. The minimum inhibitory concentration (MIC) analysis results revealed that of the 515 isolates tested, bacteria with significantly increased MIC levels against colistin were isolated in 2019. Approximately one-fifth (17.14% to 19.65%) of the isolates showed MIC values ≥1 mg/L against colistin in 2015, 2016, and 2017. However, in 2019, up to three-quarters (74.11%, 146/197) of the isolates showed MIC values ≥1 mg/L against colistin indicating an increase in colistin resistance. Six isolates (EC7518, EC4968, EC3769, EC16, EC117, EC195, 1.13%, 6/515) were found to carry the mcr-1 gene and a novel mcr-1 variant with Met2Ile mutation was identified in EC3769. All six strains showed higher MIC levels (MIC=4 mg/L) than any mcr-1-negative strains (MIC ≤ 2 mg/L). Whole-genome sequencing of the six mcr-1-positive isolates revealed that EC195 carried the highest number of resistance genes (n = 28), nearly a half more than those of the following EC117 (n = 19). Thus, EC195 showed a wider resistance spectrum and higher MIC levels against the antimicrobials tested than the other five isolates. Multi-locus sequence typing demonstrated that these mcr-1-positive strains belonged to six different sequence types. The six mcr-1 genes were located in three different incompatibility group plasmids (IncI2, IncHI2 and IncX4). The genetic context of mcr-1 was related to a sequence derived from Tn6330 (ISApl1-mcr-1-pap2-ISApl1). Investigations into the colistin resistance mechanism and characterization of the molecular background of the mcr genes may help trace the development and spread of colistin resistance in clinical settings.

A Multicenter Study of Viral Aetiology of Community-Acquired Pneumonia in Hospitalized Children in Chinese Mainland.

Community-acquired pneumonia (CAP) is one of the leading causes of morbidity and mortality in children worldwide. In this study, we aimed to describe the aetiology of viral infection of pediatric CAP in Chinese mainland. During November 2014 to June 2016, the prospective study was conducted in 13 hospitals. The hospitalized children under 18 years old who met the criteria for CAP were enrolled. The throat swabs or nasopharyngeal aspirates (NPAs) were collected which were then screened 18 respiratory viruses using multiplex PCR assay. Viral pathogens were present in 56.6% (1539/2721) of the enrolled cases, with the detection rate of single virus in 39.8% of the cases and multiple viruses in 16.8% of the cases. The most frequently detected virus was respiratory syncytial virus (RSV) (15.2%, 414/2721). The highest detection rate of virus was in < 6-month-age group (70.7%, 292/413). RSV, human metapneumovirus (HMPV), human parainfluenza viruses (HPIVs) and influenza B virus (Flu B) showed the similar prevalence patterns both in north and south China, but HPIVs, Flu A, human bocavirus (HBoV), human adenovirus (HAdV) and human coronaviruses (HCoVs) showed the distinct circulating patterns in north and south China. Human enterovirus/human rhinovirus (HEV/HRV) (27.6%, 27/98), HBoV (18.4%, 18/98), RSV (16.3%, 16/98) and HMPV (14.3%, 14/98) were the most commonly detected viruses in severe pneumonia cases with single virus infection. In conclusion, viral pathogens are frequently detected in pediatric CAP cases and may therefore play a vital role in the aetiology of CAP. RSV was the most important virus in hospitalized children with CAP in Chinese mainland.

Molecular Characteristics of Human Adenovirus Type 3 Circulating in Parts of China During 2014-2018.

Human adenoviruses (HAdVs) are important pathogens causing respiratory infections; 3.5-11% of childhood community-acquired pneumonia is associated with HAdV infection. Human adenovirus type 3 (HAdV-3), leading to severe morbidity and mortality, is one of the most prevalent genotype among adenoviruses responsible for acute respiratory infections (ARIs) in children in China. To identify the genetic variation of HAdV-3 in children with ARIs in China, a molecular epidemiological study was conducted. A total of 54 HAdV-3 isolated strains were obtained from children with ARIs in Beijing, Wenzhou, Shanghai, Shijiazhuang, Hangzhou, Guangzhou, and Changchun from 2014 to 2018. Thirty-two strains of which were selected for whole-genome sequencing, while the hexon, penton base, and fiber genes were sequenced for remaining strains. Bioinformatics analysis was performed on the obtained sequences. The phylogenetic analyses based on whole-genome sequences, major capsid protein genes (hexon, penton base, and fiber), and early genes (E1, E2, E3, and E4) showed that the HAdV-3 strains obtained in this study always clustered together with the reference strains from Chinese mainland, while the HAdV-3 prototype strain formed a cluster independently. Compared with the prototype strain, all strains possessed nine amino acid (AA) substitutions at neutralization antigenic epitopes of hexon. The homology models of the hexon protein of the HAdV-3 prototype and strain BJ20160214 showed that there was no evident structural change at the AA mutation sites. Two AA substitutions were found at the Arg-Gly-Asp (RGD) loop and hypervariable region 1 (HVR1) region of the penton base. A distinct AA insertion (20P) in the highly conserved PPPSY motif of the penton base that had never been reported before was observed. Recombination analysis indicated that partial regions of protein IIIa precursor, penton base, and protein VII precursor genes among all HAdV-3 strains in this study were from HAdV-7. This study showed that the genomes of the HAdV-3 strains in China were highly homologous. Some AA mutations were found at antigenic sites; however, the significance needs further study. Our data demonstrated the molecular characteristics of HAdV-3 circulating in China and was highly beneficial for further epidemiological exploration and the development of vaccines and drugs against HAdV-3.

The Epidemiology, Molecular, and Clinical of Human Adenoviruses in Children Hospitalized With Acute Respiratory Infections.

INTRODUCTION: Human adenovirus (HAdV) is a common pathogen in children with acute respiratory infections (ARIs). The aim was to describe the epidemiology, molecular, and clinical characteristics of HAdV among children hospitalized with ARIs in Wenzhou in southeastern China. METHODOLOGY: From January 2018 to December 2019, nasopharyngeal swab or sputum specimens were prospectively collected from hospitalized children with ARIs. HAdV was detected using direct immunofluorescence. We used a multiplex PCR assay combined with capillary electrophoresis targeting the hexon gene's hypervariable region to identify HAdV types 1, 2, 3, 4, 5, 7, 14, 21, 37, 40, 41, and 55. We analyzed the epidemiological, molecular, and clinical data according to the HAdV type. RESULTS: HAdVs were detected in 1,059 (3.5%) of the total of 30,543 children tested. A total of 947 cases with monotype HAdV identified by the PCR assay were included in the analysis. HAdV-3 (415/947, 43.8%), HAdV-7 (318/947, 33.6%), HAdV-2 (108/947, 11.4%), and HAdV-1 (70/947, 7.4%) were the predominant types. Of the 550 (58.1%) cases detected from December 2018 to August 2019, HAdV-3, and HAdV-7 were the main types. The main diagnoses included 358 cases of pneumonia, 232 cases of tonsillitis, 198 cases of bronchitis, and 159 cases of upper respiratory tract infection (URTI). Among children with pneumonia the main types were HAdV-7 (51.1%), HAdV-3 (36.9%), and HAdV-1 (2.2%). Among children with bronchitis, the main types were HAdV-3 (48.0%), HAdV-7 (28.3%), and HAdV-2 (10.6%). Among children with URTIs, the main types were HAdV-3 (49.7%), HAdV-7 (22.6%), and HAdV-2 (13.2%). Among children with tonsillitis, the main types were HAdV-3 (47.4%), HAdV-2 (22.4%), and HAdV-7 (18.5%). In total, 101 (55.2%) patients required supplemental oxygen, 15 (8.2%) required critical care, and 1 child (0.5%) with HAdV-7 pneumonia died. CONCLUSION: HAdV-3 -7, -2, and -1 were the predominant types identified in hospitalized children with ARIs in Wenzhou. From December 2018 to August 2019, there were outbreaks of HAdV-3 and -7. There were significant differences in HAdV types among children with pneumonia, tonsillitis, bronchitis, and URTI. HAdV-7 can cause more severe pneumonia in children than HAdV-3.

Genetic Analysis of Human Adenovirus Type 7 Strains Circulating in Different Parts of China.

To investigate the molecular epidemiology and genetic variation of human adenovirus type 7 (HAdV-7) in children with acute respiratory infections (ARI) in China. HAdV-7-positive respiratory samples collected from children with ARI in Beijing, Shijiazhuang, Wenzhou and Guangzhou from 2014-2018 were selected for gene amplification and sequence analysis. Fifty-seven HAdV-7 clinical strains with hexon, penton base and fiber gene sequences were obtained. Meanwhile 17 strains were selected randomly from different cities for whole genome sequencing. Phylogenetic and variation analyses were performed based on the obtained sequences, HAdV-7 prototype strain Gomen (AY594255), vaccine strains (AY495969 and AY594256) and representative sequences of strains. The phylogenetic trees constructed based on whole genome sequences, major capsid protein genes (hexon, penton base and fiber) and the early genes (E1, E2, E3 and E4) were not completely consistent. The HAdV-7 strains obtained in this study always clustered with most of the circulating strains worldwide from the 1980s to the present. Compared with the HAdV-7 prototype strain Gomen (AY594255), some amino acid mutations in loop1 and loop2 of hexon and the RGD loop region of the penton base gene were observed. Recombination analysis showed that partial regions of 55 kDa protein and 100 kDa hexon-assembly associated protein genes among all HAdV-7 strains in this study were from HAdV-16 and HAdV-3, respectively. Our study demonstrated the molecular evolution characteristics of HAdV-7 strains circulating in China and provided basic reference data for the prevention, control and vaccine development of HAdV-7.

WU Polyomavirus Infection in Children With Acute Lower Respiratory Tract Infections in China, 2017 to 2019: Case Reports and Multicentre Epidemiological Survey.

WU polyomavirus (WUPyV) is a novel member of the family Polyomaviridae recently detected in respiratory tract specimens. So far, it has not been proven whether WUPyV is a real causative agent for respiratory diseases. In this study, we described two patients with fatal infection who had WUPyV detected in their nasopharyngeal swabs. Furthermore, we conducted a multicentre study in six hospitals from different districts of China. WUPyV was detected by real-time polymerase chain reaction assays, and the clinical and molecular epidemiological characteristics of WUPyV strains among hospitalized children with acute lower respiratory tract infections all around China from 2017 to 2019 were analysed. Two complete WUPyV genome sequences were assembled from fatal patients' airway specimens. Phylogenetic tree analysis revealed that they were most closely related to strains derived from Fujian and Chongqing, China, in 2008 and 2013, respectively. In 2017-2019, a total of 1,812 samples from children with acute lower respiratory tract infections were detected for WUPyV, of which 11 (0.6%) were positive. Children aged ≤5 were more susceptible to WUPyV infection. A total of 81.8% of WUPyV-positive patients were coinfected with other viruses, of which rhinovirus enjoyed the highest frequency. The main clinical symptoms of infected patients include fever, coughing and sputum expectoration. Most patients were diagnosed with pneumonia, followed by bronchial surgery. Three patients manifested severe infection, and all patients improved and were discharged. Our results show that WUPyV persistently circulates in China. Further investigations on the clinical role and pathogenicity of WUPyV are necessary.

Caffeine prevents hyperoxia-induced lung injury in neonatal mice through NLRP3 inflammasome and NF-κB pathway.

BACKGROUND: Bronchopulmonary dysplasia (BPD) is a common chronic lung disease in premature infants and hyperoxia exposure is a major cause. In hyperoxic lung injury animal model, alveolar simplification and pro-inflammatory cells infiltration are the main pathophysiologic changes. Caffeine is a drug used to treat apnea in premature infants. Early use of caffeine can decrease the rate and the severity of BPD while the mechanisms are still unclear. The purpose of this study was to evaluate the effects of caffeine on inflammation and lung development in neonatal mice with hyperoxic lung injury and to explore the possible mechanism. METHODS: Following 14 d of 75% oxygen exposure in newborn mouse, the BPD model was established. Caffeine at a dose of 1 g/L was added in drinking water to nursing mouse. We measured the concentration of caffeine in serum and oxidative stress in lung by commercially available kits. Adenosine 2A receptor (A2AR) expression and lung inflammation were measured by Immunohistochemistry and western blotting. Apoptosis and surfactant protein-C (SFTPC) levels were measured by immunofluorescence. The inflammasome and NF-κB pathway proteins were assessed by western blotting. RESULTS: We found that the caffeine concentration in plasma at present dose significantly decreased the expression of A2AR protein in mice lung. Caffeine treatment significantly reduced oxidative stress, improved weight gain, promoted alveolar development, attenuated inflammatory infiltration and lung injury in hyperoxia-induced lung injury mice. Moreover, caffeine decreased the cell apoptosis in lung tissues, especially the Type II alveolar epithelial cell. The expression of NLRP3 inflammasome protein and NF-κB pathway were significantly inhibited by caffeine treatment. CONCLUSION: Caffeine treatment can protect hyperoxia-induced mice lung from oxidative injury by inhibiting NLRP3 inflammasome and NF-κB pathway.

Changes in the etiology of viral lower respiratory tract infections in hospitalized children in Wenzhou, China: 2008-2017.

This study investigated the seasonality and secular trends in the etiology of viral lower respiratory tract infections (LRTIs) among hospitalized children in Wenzhou, southeastern China. A retrospective review was conducted concerning viral LRTIs in children hospitalized at a university hospital between January 1, 2008 and December 31, 2017. Direct immunofluorescence was used to detect respiratory syncytial virus (RSV), adenovirus (AdV), influenza A virus (Inf A), influenza B virus (Inf B), and human parainfluenza virus types 1 to 3 (hPIV1-3). Of 89 898 children tested, at least one viral respiratory pathogen was identified in 25.6% and multiple pathogens were identified in 0.4%. RSV (17.6%), hPIV3 (4.0%), and AdV (2.2%) were the most frequently detected pathogens. The proportion of positive samples varied with age and was the highest in children aged <6 months (36.2%). Seasonal differences were observed in RSV, AdV, Inf A, Inf B, hPIV1, and hPIV3 infections. There was a declining trend in the proportion of positive samples over time, primarily due to a decrease in RSV and hPIV3 infections. RSV, hPIV3, and AdV were the most common viral respiratory pathogens identified among hospitalized children with LRTIs. The distribution of viruses varied with age and season.

Lipoxin A4 reduces hyperoxia-induced lung injury in neonatal rats through PINK1 signaling pathway.

Bronchopulmonary dysplasia (BPD) is a common chronic lung disease in premature infants and is mainly caused by hyperoxia exposure and mechanical ventilation. Alveolar simplification, pulmonary vascular abnormalities and pulmonary inflammation are the main pathological changes in hyperoxic lung injury animals. Lipoxin A4 (LXA4) is an important endogenous lipid that can mediate the regression of inflammation and plays a role in acute lung injury and asthma. The purpose of this study was to evaluate the effects of LXA4 on inflammation and lung function in neonatal rats with hyperoxic lung injury and to explore the mechanism of the PINK1 pathway. After 85% oxygen exposure in newborn rats for 7 days, the BPD model was established. We found that LXA4 could significantly reduce cell and protein infiltration and oxidative stress in rat lungs, improve pulmonary function and alveolar simplification, and promote weight gain. LXA4 inhibited the expression of TNF-α, MCP-1 and IL-1ß in serum and BALF from hyperoxic rats. Moreover, we found that LXA4 could reduce the expression of the PINK1 gene and down-regulate the expression of PINK1, Parkin, BNIP3L/Nix and the autophagic protein LC3B.These protective effects of LXA4 could be partially reversed by addition of BOC-2.Thus, we concluded that LXA4 can alleviate the airway inflammatory response, reduce the severity of lung injury and improve lung function in a hyperoxic rat model of BPD partly through the PINK1 signaling pathway.

Liver Failure in a Chinese Cystic Fibrosis Child With Homozygous R553X Mutation.

Cystic fibrosis (CF) is a relatively rare disease in Asians with various clinical characteristics, including CF-associated liver disease (CFLD), which is a common early non-pulmonary complication. This case report describes a Chinese CF patient harboring a homozygous nonsense mutation (c.1657C>T, p.R553X) who was failure to thrive and had intermittently diarrhea during the first year after birth. Liver function test of the patient showed the mildly and intermittently elevated alanine aminotransferase (ALT) levels ranging from 70 to 92 U/L and aspartate aminotransferase (AST) levels ranging from 80 to 90 U/L, which began at 8 months of age and lasted for 4 years without CF diagnosis. In addition, abdominal computed tomography (CT) revealed diffuse fatty infiltration of the liver at 4 years old and gradually developed hepatic cirrhosis. Subsequently, cirrhosis rapidly progressed with obvious splenomegaly and pancreatic insufficiency and the patient died of liver failure with coagulopathy by the age of 6 years old. Pediatricians should remain vigilant to avoid failure to diagnose CF, the occurrence of which may be underestimated, and pay greater attention to the patients with atypical clinical manifestations in Asian countries.

Adiponectin alleviates exacerbation of airway inflammation and oxidative stress in obesity-related asthma mice partly through AMPK signaling pathway.

Adiponectin plays a role in asthma and obesity, but its effects and mechanism in obesity-related asthma remain elusive. This study aimed to evaluate the effects of adiponectin on airway inflammation and oxidative stress and to determine its mechanism in obesity-related asthma. Male C57BL6/J mice fed with a high-fat diet to induce obesity were sensitized and challenged with ovalbumin to induce asthma, and treated with adiponectin (1 mg/kg) and AMP-activated protein kinase (AMPK) inhibitor compound C (20 mg/kg) twice before the first ovalbumin challenge. We found exogenous adiponectin significantly reduced airway resistance, inflammatory infiltration in lung tissue, and cell counts in bronchoalveolar lavage fluid. Adiponectin inhibited great levels of eotaxin, myeloperoxidase, tumor necrosis factor-α, 8­hydroxy­2'­deoxyguanosine, and nitric oxide in obesity-related asthma mice. Moreover, we found increased nuclear factor kappa B p65, inducible nitric oxide synthase and B-cell lymphoma 2 protein expression were down-regulated with adiponectin administration. Additionally, adiponectin elevated the lower levels of pAMPK and AMPK activity in lung tissue. These protective effects of adiponectin were reversed after treatment with the AMPK inhibitor compound C. Thus, we conclude that adiponectin alleviates exacerbation of airway inflammation and oxidative stress in a murine model of obesity-related asthma partly through AMPK signaling pathway.

MicroRNA-133a alleviates airway remodeling in asthtama through PI3K/AKT/mTOR signaling pathway by targeting IGF1R.

Asthma is characterized by chronic inflammation, and long-term chronic inflammation leads to airway remodeling. But the potential regulatory mechanism of airway remodeling is not clearly understood, and there is still no effective way to prevent airway remodeling. Present studies have confirmed the role of microRNAs (miRNAs) in the development of disease, which is known as suppressing translation or degradation of messenger RNA (mRNA) at the posttranscriptional stage. In this study, we described the role of miRNA-133a in asthma and demonstrated it in regulating airway remodeling of asthma through the phosphoinositide 3 kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway by targeting IGF-1 receptor (IGF1R). IGF1R helps in mediating the intracellular signaling cascades. Asthmatic mice models were established by sensitization and Ovalbumin challenge. Adenovirus transfer vector carrying miR-133a or miR-133a sponge sequence was used to build the overexpression or downexpression of miR-133a modeling. Real-time polymerase chain reaction and Western blot were used to determine the alterations in the expression of miR-133a and mRNAs and their corresponding proteins. Results showed that miR-133a was downregulated in asthma. Upregulation of miR-133a expression in airway smooth muscle cells in vivo and in vitro could inhibit the activation of PI3K/AKT/mTOR pathway, and reduce the expression of α-smooth muscle actin (α-SMA), indicating that airway remodeling was inhibited. Functional studies based on luciferase reporter revealed miR-133a as a direct target of IGF1R mRNA. In conclusion, these data suggested that miR-133a regulated the expression of α-SMA through PI3K/AKT/mTOR signaling by targeting IGF1R. miR-133a plays a key role in airway remodeling of asthma and may serve as a potential therapeutic target for managing asthmatic airway remodeling.

Current perspectives on the correlation of nocturnal enuresis with obstructive sleep apnea in children.

BACKGROUND: Obstructive sleep apnea (OSA) and nocturnal enuresis (NE) are common clinical problems in children. OSA and NE are thought to be interrelated, but the exact pathophysiological mechanisms are not yet clear. This review aims to explain the possible pathogenesis of NE in children with OSA. DATE SOURCES: We have retrieved all relevant original articles from Database that have been published so far, including the prevalence studies of NE and OSA in children, sleep characteristic studies that use polysomnography (PSG) to focus on children with NE, and studies on the relationship between OSA and NE. RESULTS: Clinical studies have revealed that the risk of NE in children with OSA was increased compared with that of their healthy peers. This increased risk may be associated with sleep disorders, bladder instability, detrusor overactivity, nocturnal polyuria, endocrine and metabolic disorders, and inflammation. CONCLUSIONS: Cardiopulmonary and renal reflex-induced neuroendocrine disorder may play an important role in the mechanism of NE in children with OSA, but this remains to be confirmed by animal studies. Other causes such as oxidative stress and inflammatory responses need to be further researched.

Genetic variations in the fusion protein of respiratory syncytial virus isolated from children hospitalized with community-acquired pneumonia in China.

To identify the variations in fusion (F) protein gene of RSV in China, a molecular epidemiological study was conducted. A total of 553 RSV positive specimens were collected from 2338 pediatric patients hospitalized with community-acquired pneumonia during a multi-center study conducted during 2014-2016. A total of 252 samples (183 RSV A, 69 RSV B) were selected for F gene sequencing, and analyzed together with 142 F gene sequences downloaded from GenBank. The result showed that all the Chinese RSV A and RSV B strains could be divided respectively into three branches. Compared with RSV A/B prototype sequences respectively, there were significant amino acid (AA) mutations at multiple antigenic sites. For RSV A, changes were found at AA residues 122, 124, 125, 276 and 384, and for RSV B at AA residues 45, 116, 125, 172, 173 and 202. Variations in human histocompatibility leukocyte antigen-restricted CTL epitopes were also observed. In total, 56 amino acid differences for the complete F protein were found between the RSV A and B groups in China, while several mutations were only found in the RSV B strains during 2015-2016. The RSV F gene is relatively conserved in China, however, limited mutations are still occurring with time.

High-fat-diet induces airway hyperresponsiveness partly through activating CD38 signaling pathway.

CD38 is a plasma membrane bound multifunctional enzyme. It can be activated by inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-13, inducing calcium responses to agonist in airway smooth muscle cells (ASMC). Previous studies have found that high-fat-diet (HFD) induced obesity exhibited innate airway hyperresponsiveness (AHR). This study aimed to detect the effect of CD38 signaling pathway on the AHR of overweight/obese mice. The HFD-fed mice exhibited a significantly higher baseline airway resistance (Rn), and the increasing rates of Rn responded to increasing doses of methacholine compared with the LFD-fed mice. High-fat-diet increased CD38 expressions both in lung tissues and primary cultured ASMCs. Besides, preincubation with TNF-α led to a higher expression of CD38 protein and increased intracellular calcium in ASMC of the HFD-fed mice. Furthermore, CD38 gene knockdown through transfection of CD38 siRNA decreased the concentration of intracellular calcium. Additionally, the upregulations of CD38 protein and CD38 mRNA were also found in the lung tissues of HFD-fed mice challenged by ovalbumin (OVA). Collectively, our findings demonstrated a role of CD38 signaling pathway on the AHR of obesity and might be a potential therapeutic target for treating difficult-to-control obese asthma phenotype.

TNF-α increases Staphylococcus aureus-induced death of human alveolar epithelial cell line A549 associated with RIP3-mediated necroptosis.

AIM: To explore the role of tumor necrosis factor-alpha (TNF-α) on Staphylococcus aureus-induced necroptosis in alveolar epithelial cells. MAIN METHODS: The A549 alveolar epithelial cell line was pretreated with small interfering RNA (siRNA) against receptor interacting protein-3 (RIP3) and then stimulated by S. aureus, where some cells were pretreated with TNF-α or TNF-α with anti-TNF-α antibody simultaneously. A549 cell death was assessed using lactate dehydrogenase (LDH) leakage and flow cytometry analyses. The protein expressions of RIP1, RIP3, cleaved caspase-1, and cleaved caspase-8 were analyzed by western blot. KEY FINDINGS: S. aureus-induced LDH release was increased significantly by TNF-α. In addition, flow cytometry showed that TNF-α increased A549 cell apoptosis and necrosis in S. aureus-infected cell cultures. Levels of RIP3 and cleaved caspase-1 protein in A549 cells infected with S. aureus increased at 12 h post-infection, as shown by western blot. Significant additional increases in RIP3 expression were observed following the addition of TNF-α. Decreasing RIP3 levels by siRNA significantly suppressed the release of LDH induced by TNF-α and S. aureus. RIP3 siRNA also significantly suppressed A549 cell necrosis induced by S. aureus and TNF-α at 6 and 12 h post-infection as shown by flow cytometry analysis. SIGNIFICANCE: TNF-α enhances the damage of S. aureus on lung epithelial cells, and its mechanism is associated with RIP3 mediated necroptosis.

[Streptococcus pneumoniae induces SPLUNC1 and the regulatory effects of resveratrol].

OBJECTIVE: To investigate the host-defense role of short palate, lung, and nasal epithelium clone 1 (SPLUNC1) in Streptococcus pneumoniae (SP) infection and the effect of resveratrol (Res) on SPLUNC1 expression, and to provide new thoughts for the treatment of diseases caused by SP infection. METHODS: According to the multiplicity of infection (MOI), BEAS-2B cells with SP infection were divided into control group, MOI20 SP group, and MOI50 SP group. According to the different concentrations of Res, the BEAS-2B cells with MOI20 SP infection pretreated by Res were divided into 12.5Res+SP group, 25Res+SP group, and 50Res+SP group (the final concentrations of Res were 12.5, 25, and 50 µmol/L, respectively). Cell Counting Kit-8 was used to measure cell activity and determine the optimal concentration and action time of SP and Res. In the formal experiment, the cells were divided into control group, Res group, SP group, and Res+SP group. Real-time PCR and ELISA were used to measure the mRNA and protein expression of SPLUNC1. RESULTS: Over the time of SP infection, cell activity tended to decrease. Compared with the control group and the MOI20 SP group, the MOI50 SP group had a reduction in cell activity. Compared with the MOI20 SP group, the 25Res+SP group had increased cell activity and the 50Res+SP group had reduced cell activity (P<0.05). MOI20 SP bacterial suspension and 25 µmol/L Res were used for the formal experiment. Over the time of SP infection, the mRNA expression of SPLUNC1 in BEAS-2B cells firstly increased and then decreased in the SP group and the Res+SP group (P<0.05). Compared with the SP group, the Res+SP group had significant increases in the mRNA and protein expression of SPLUNC1 at all time points (P<0.05). Compared with the control group, the Res group had no significant changes in the mRNA and protein expression of SPLUNC1 (P>0.05). CONCLUSIONS: SP infection can induce SPLUNC1 expression and the host-defense role of SPLUNC1. Res can upregulate SPLUNC1 expression during the development of infection and enhance cell protection in a concentration- and time-dependent manner.