Jun Xie’s research while affiliated with Chongqing Medical University and other places

High mobility group box-1 (HMGB1) is implicated in airway inflammation during the late phase of respiratory syncytial virus (RSV) infection. Despite its recognized role, the specific mechanism underlying its release post-RSV infection remains ambiguous. The nonstructural protein 1 (NS1) has been associated with interactions with numerous host proteins, affecting diverse physiological processes, and it is speculated to be involved in the release of HMGB1. We utilized an in vivo model of RSV-infected mice and an in vitro model of RSV-infected A549 and 16HBE cells to investigate the role of NS1 in promoting HMGB1 release. Small interfering RNA was employed to deplete NS1, while lentiviral vectors were used for NS1 overexpression. The interaction between NS1 and H1.0 was confirmed by immunofluorescence analysis, immunoprecipitation, GST pull-down assays, surface plasmon resonance analysis and in silico study. Our study revealed that silencing the NS1 gene reduced the levels of HMGB1 protein and suppressed airway inflammation during the late stage of RSV infection. Depletion of NS1 led to decreased levels of intracellular and extracellular HMGB1 in A549 and 16HBE cells, while over-expression of NS1 increased HMGB1 expression. Furthermore, NS1 and HMGB1 directly interacted with histone H1.0, as confirmed by GST pull-down, surface plasmon resonance and in silico analyses. Overexpression of NS1 disrupted the binding of HMGB1 to H1.0, while silencing of NS1 enhanced their interaction. The research findings indicate that NS1 interacts with H1.0, thereby inhibiting the binding of HMGB1 to H1.0. Consequently, this interaction results in the release of HMGB1 into both the cytoplasm and the extracellular space.

Glucocorticoid resistance is a challenging problem in clinical practice. Increasing glucocorticoid sensitivity and reducing resistance are important in the management of certain diseases. In steroid-resistant airway inflammatory diseases, glucocorticoid receptor (GR) expression is reduced, and impaired GR nuclear translocation is closely related to glucocorticoid resistance. Histone deacetylase SIRT1 regulates steroid hormone receptor activity and interacts with the androgen receptor and GR. In some glucocorticoid-resistant diseases, SIRT1 expression is reduced. Here, we review recent advances in the role of SIRT1 in regulating glucocorticoid signaling. First, we describe the structure, tissue expression, and subcellular localization of SIRT1. We also discuss the molecular mechanisms by which SIRT1 regulates glucocorticoid activity and its association with GR, as well as the mechanisms and roles of SIRT1 in several common glucocorticoid-resistant diseases. SIRT1 may serve as a potential therapeutic target, providing an opportunity for the treatment of glucocorticoid-resistant diseases.

Objectives Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection (LRTI). However, few comprehensive descriptions of the disease burden, medical resource utilization (MRU), and costs of RSV are available for China. This study aimed to provide the basis for the development of RSV prevention strategies by analyzing the burden of RSV among inpatients with lower respiratory tract infection under 5 years of age. Methods We conducted a retrospective hospital-based study from June 2009 to May 2019 in Chongqing. Inpatients with LRTI were tested for eight viruses. We analyzed the RSV disease burden, MRU, and direct hospitalization costs by using non-parametric Mann‒Whitney U test, Chi-squared test or Fisher's exact test and logistic regression. Results A total of 6991 children under 5 years of age with LRTI were included in this study. The overall RSV-positive rate was 34.5% (2410/6991). Prior to admission, 81.9% (1973/2410) of these RSV-positive cases were otherwise healthy. Compared with children aged 24–59 months, the odds ratio (OR) and 95% confidence interval (CI) for RSV infection were 2.509 (2.139–2.945), 1.882 (1.549–2.222), and 1.479 (1.240–1.765) for those aged 1–5 months, 6–11 months, and 12–23 months, respectively. The proportions of patients treated with invasive ventilation and continuous positive airway pressure (CPAP) were significantly higher among RSV-positive cases (1.1% [27/2410] and 3.9% [93/2410]) than RSV-negative cases (0.9% [43/4581] and 2.7% [124/4581]) (P = 0.023). Compared with RSV-negative cases, RSV-positive cases had significantly longer hospital length of stay (6 [5, 8] days vs. 6 [5, 8] days, P < 0.001) and higher hospitalization costs (963.0 [757.9, 1298.5] USD vs. 935.6 [719.7, 1296.3] USD, P = 0.022). Conclusions Most RSV infections occurred during early childhood and among individuals in the otherwise healthy group. Younger age was associated with a higher RSV-positive rate. Effective prevention measures are needed in the earliest stages to reduce the RSV burden.

Background: Respiratory syncytial virus (RSV), which is the predominant viral pathogen responsible for causing acute lower respiratory tract infections in children, currently lacks specific therapeutic drugs. Despite andrographolide's demonstrated effectiveness against various viral infections, its effects on RSV infection remain unclear. Methods: In this study, RSV infection and andrographolide-intervened A549 cell lines were used. The virus load of RSV and the levels of IL-6 and IL-8 in the cell supernatant were quantified. The potential targets of andrographolide in the treatment of RSV-infected airway epithelial cells were analyzed using the Gene Expression Omnibus (GEO) database and the PharmMapper Database, and the changes in mRNA expression of these target genes were measured. To further illustrate the effect of andrographolide on the death pattern of RSV-infected airway epithelial cells, Annexin V-FITC/PI apoptosis assays and Western blotting were conducted. Results: Andrographolide decreased the viral load and attenuated IL-6 and IL-8 levels in cell supernatant post-RSV infection. A total of 25 potential targets of andrographolide in the treatment of RSV-infected airway epithelial cells were discovered, and CASP1, CCL5, JAK2, and STAT1 were identified as significant players. Andrographolide noticeably suppressed the increased mRNA expressions of these genes post-RSV infection as well as IL-1β. The flow cytometry analysis demonstrated that andrographolide alleviated apoptosis in RSV-infected cells. Additionally, RSV infection decreased the protein levels of caspase-1, cleaved caspase-1, cleaved IL-1β, N-terminal of GSDMD, and Bcl-2. Conversely, andrographolide increased their levels. Conclusion: These results suggest that andrographolide may reduce RSV-induced inflammation by suppressing apoptosis and promoting pyroptosis in epithelial cells, leading to effective viral clearance.

Respiratory syncytial virus (RSV) is one of the most common causes of lower respiratory tract infections (LRTI). However, only limited information is available regarding its seasonality and its relationship with birth month. A retrospective hospital-based study was carried out from June 2009 to May 2019 in Chongqing, southwest of China. LRTI cases under 5 years were enrolled in this study and PCR was used to detect 8 respiratory viruses. RSV seasonality was determined using "average annual percentage" (AAP) and "percent positivity" method. A total of 6991 cases were enrolled in this study, with an RSV positivity of 34.5%. From June 2009 to May 2019, we analyzed RSV epidemic season during 10 RSV epidemic years in Chongqing using two methods. The result of AAP method was similar to that of percent positivity method with a 30% threshold, which showed an epidemic season of roughly October to March in the subsequent year, with a small peak in June. On average, the RSV epidemic season in RSV-A dominant years typically started earlier (week 42 for RSV-A vs. week 46 for RSV-B), ended earlier (week 12 for RSV-A vs. week 14 for RSV-B), lasted longer (24 weeks for RSV-A vs. 22 weeks for RSV-B), and reached its peak earlier (week 2 for RSV-A vs. week 3 for RSV-B) than in RSV-B dominant years. The proportion of severe LRTI was higher in cases of single infection with RSV-A compared to those of single infection with RSV-B (26.3% vs. 22.3%, p = 0.024). Among infants under 1 year, those born in May and August through December were more likely to be infected with RSV. Infants born 1-2 months before the epidemic season were relatively more susceptible to RSV infection. In Chongqing, the RSV epidemic was seasonal and usually lasted from October to March of next year with a small peak in summer. Infants born 1-2 months before the epidemic season were relatively more susceptible to RSV infection and this population should be targeted while developing RSV immunization strategies.

Background Respiratory syncytial virus (RSV) is the leading cause of mortality and morbidity in children under the age of five. Despite this, there is still a lack of safe and effective vaccines and antiviral agents for clinical use. Andrographolide exerts antiviral functions against a variety of viruses, but whether (and how) it exerts antiviral effects on RSV remains unclear. Methods and results In vitro RSV infection models using A549 and 16HBE cell lines were established, and the effects of andrographolide on RSV were analyzed via RSV N gene load and proinflammatory cytokine levels. The RNA transcriptome was sequenced, and data were analyzed by R software. Andrographolide-related target genes were extracted via network pharmacology using online databases. Lentiviral transfection was applied to knockdown the heme oxygenase-1 gene (Hmox1, HO-1). Results showed that andrographolide suppressed RSV replication and attenuated subsequent inflammation. Network pharmacology and RNA sequencing analysis indicated that the hub gene HO-1 may play a pivotal role in the anti-RSV effects of andrographolide. Furthermore, andrographolide exerted antiviral effects against RSV partially by inducing HO-1 but did not activate the antiviral interferon response. Conclusion Our findings demonstrated that andrographolide exerted anti-RSV activity by up-regulating HO-1 expression in human airway epithelial cells, providing novel insights into potential therapeutic targets and drug repurposing in RSV infection.

Background IL-17A is a pleiotropic cytokine and intimately associated with asthma, but its role in respiratory syncytial virus (RSV) infection is conflicting in the literature. Methods Children hospitalized in the respiratory department with RSV infection during RSV pandemic season of 2018–2020 were included. Nasopharyngeal aspirates were collected for pathogen and cytokines determination. In the murine model, RSV intranasal administrations were performed in wild-type and IL-17A-/- mice. Leukocytes and cytokines in bronchoalveolar lavage fluid (BALF), lung histopathology, and airway hyperresponsiveness (AHR) were measured. RORγt mRNA and IL-23R mRNA were semi-quantified by qPCR. Results IL-17A increased significantly in RSV-infected children and was positively associated with pneumonia severity. In the murine model, IL-17A significantly increased in BALF of mice with RSV infection. Airway inflammation, lung tissue damage and AHR were significantly alleviated in wild-type mice following IL-17A neutralization and in the IL-17A-/- mice. IL-17A decreased by removing CD4⁺ T cells but increased by depleting CD8⁺ T cells. IL-6, IL-21, RORγt mRNA and IL-23R mRNA dramatically increased in parallel with the rise of IL-17A. Conclusions IL-17A contributes to the airway dysfunctions induced by RSV in children and murine. CD3⁺CD4⁺T cells are its major cellular sources and the IL-6/IL-21-IL-23R-RORγt signaling pathway might participate in its regulation.

Background Andrographolide sulfonate (Andro-S), a traditional Chinese medicine, is commonly used to treat pediatric respiratory tract infections in China. However, its therapeutic effects in infections caused by respiratory syncytial virus (RSV) have not been reported. We thus aimed to investigate the therapeutic effects of Andro-S using a mouse model of RSV infection-induced airway inflammation. Methods Immunocompromised (cyclophosphamide-treated) BALB/c mice were intranasally infected with RSV and treated with intranasal or intraperitoneal Andro-S once daily for five consecutive days, starting on the day of infection. Histopathological changes in the lung were evaluated using hematoxylin and eosin staining. Total inflammatory cell counts and macrophage, lymphocyte, neutrophil, and eosinophil counts in the bronchoalveolar lavage fluid (BALF) were microscopically determined. Interferon-γ (IFN-γ) levels in the BALF were detected using enzyme-linked immunosorbent assay (ELISA). The messenger RNA levels of RSV nucleoprotein (N) and Toll-like receptors (TLRs) 1–9 in lung tissues were determined with quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels of RSV N, RSV fusion protein (F), TLR2, TLR3, and TIR domain-containing adapter-inducing interferon-β (TRIF) were detected via Western blot analysis. Results RSV infection caused lung inflammation, manifesting as bronchiolitis, alveolitis, and perivascular inflammation; increased the number of inflammatory cells; and elevated IFN-γ levels in the BALF. Lung inflammation was positively correlated with pulmonary RSV N levels in infected mice. Intranasal Andro-S significantly downregulated RSV N, RSV F, TLR3, and TRIF protein expression in the lung and ameliorated lung inflammation in infected animals. However, intraperitoneal Andro-S showed no effects on lung inflammation caused by RSV infection. Conclusions Intranasal Andro-S inhibits RSV replication and ameliorates RSV infection-induced lung inflammation by downregulating TLR3 and TRIF. Therefore, intranasal administration may be a suitable drug delivery method for treating RSV infection.