Deciphering the molecular regulatory of RAB32/GPRC5A axis in chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a significant public health problem characterized by persistent airflow limitation. Despite previous research into the pathogenesis of COPD, a comprehensive understanding of the cell-type-specific mechanisms in COPD remains lacking. Recent studies have implicated Rab GTPases in regulating chronic immune response and inflammation via multiple pathways. In this study, the molecular regulating mechanism of RAB32 in COPD was investigated by multiple bioinformatics mining and experimental verification. METHODS: We collected lung tissue surgical specimens from Zhongshan Hospital, Fudan University, and RT-qPCR and western blotting were used to detect the expression of Rabs in COPD lung tissues. Four COPD microarray datasets from the Gene Expression Omnibus (GEO) were analyzed. COPD-related epithelial cell scRNA-seq data was obtained from the GSE173896 dataset. Weighted gene co-expression network analysis (WGCNA), mfuzz cluster, and Spearman correlation analysis were combined to obtain the regulatory network of RAB32 in COPD. The slingshot algorithm was used to identify the regulatory molecule, and the co-localization of RAB32 and GPRC5A was observed with immunofluorescence. RESULTS: WGCNA identified 771 key module genes significantly associated with the occurrence of COPD, including five Rab genes. RAB32 was up-regulated in lung tissues from subjects with COPD as contrast to those without COPD on both mRNA and protein levels. Integrating the results of WGCNA, Mfuzz clusters, and Spearman analysis, nine potential interacting genes with RAB32 were identified. Among these genes, GPRC5A exhibited a similar molecular expression pattern to RAB32. Co-expression density analysis at the cell level demonstrated that the co-expression density of RAB32 and GPRC5A was higher in type I alveolar epithelial cells (AT1s) than in type II alveolar epithelial cells (AT2s). The immunofluorescence also confirmed the co-localization of RAB32 and GPRC5A, and the Pearson correlation analysis found the relationship between RAB32 and GPRC5A was significantly stronger in the COPD lungs (r = 0.65) compared to the non-COPD lungs (r = 0.33). CONCLUSIONS: Our study marked endeavor to delineate the molecular regulatory axis of RAB32 in COPD by employing diverse methods and identifying GPRC5A as a potential interacting molecule with RAB32. These findings offered novel perspectives on the mechanism of COPD.

DNA nanoparticles targeting FOXO4 selectively eliminate cigarette smoke-induced senescent lung fibroblasts.

The pathogenesis and development of chronic obstructive pulmonary disease (COPD) are significantly related to cellular senescence. Strategies to eliminate senescent cells have been confirmed to benefit several senescence-related diseases. However, there are few reports of senolytic drugs in COPD management. In this study, we demonstrated elevated FOXO4 expression in cigarette smoke-induced senescent lung fibroblasts both in vitro and in vivo. Additionally, self-assembled DNA nanotubes loaded with single-stranded FOXO4 siRNA (siFOXO4-NT) were designed and synthesized to knockdown FOXO4 in senescent fibroblasts. We found that siFOXO4-NT can concentration- and time-dependently enter human lung fibroblasts (HFL-1 cells), thereby reducing FOXO4 levels in vitro. Most importantly, siFOXO4-NT selectively cleared senescent HFL-1 cells by reducing BCLXL expression and the BCL2/BAX ratio, which were increased in CSE-induced senescent HFL-1 cells. The findings from our work present a novel strategy for senolytic drug development for COPD therapy.

Positive sputum culture of Candida spp. as a risk factor for 30-day mortality in patients with hospital-acquired pneumonia: A propensity-score matched retrospective clinical study.

Background: Candida species (Candida spp.) are commonly isolated microorganisms from lower respiratory tract (LRT) specimens of patients with hospital-acquired pneumonia (HAP); however, the clinical significance remains controversial. This study aimed to investigate the correlation between Candida spp. in the LRT and the clinical features and prognosis of HAP. Methods: This retrospective analysis included eligible patients with HAP from the database of a prospective study carried out between 2018 and 2019 in nine Chinese hospitals. Data on demographics, clinical characteristics, and prognosis were collected and analyzed. Propensity score matching (PSM) was used to balance the baseline characteristics. Results: A total of 187 HAP patients were enrolled. After PSM of severity score, 27 cases with positive sputum culture of Candida spp. were compared with the control group at a ratio of 1:1. The Candida-positive group had more bacterial isolates in blood culture than the Candida-negative group (39.1% [9/23] vs. 7.7% [2/26], χ 2  = 6.928, effect size [ES] = 0.38, 95% CI: 0.12-0.61, P = 0.008). The proportion of patients with chronic lung diseases was significantly higher in the Candida-positive group (55.6% [15/27] vs. 22.2% [6/27], χ 2  = 6.312, ES = 0.34, 95% CI: 0.07-0.59, P = 0.012). The 30-day prognosis of HAP was significantly different between the two groups (80.8% [21/26] vs. 38.5% [10/26], χ 2  = 9.665, ES = 0.43, 95% CI: 0.19-0.66, P = 0.002). Univariable logistic regression analysis showed that LRT Candida spp. colonization was a risk factor for 30-day mortality of HAP (OR = 6.720, 95% CI: 1.915-23.577, P = 0.003). Conclusions: Candida spp. in the LRT was associated with 30-day mortality of HAP. Patients with chronic underlying lung diseases tend to have Candida spp. colonization.

Prevention of exacerbation in patients with moderate-to-very severe COPD with the intent to modulate respiratory microbiome: a pilot prospective, multi-center, randomized controlled trial.

Introduction: Considering the role of bacteria in the onset of acute exacerbation of COPD (AECOPD), we hypothesized that the use of influenza-Streptococcus pneumoniae vaccination, oral probiotics or inhaled amikacin could prevent AECOPD. Methods: In this pilot prospective, muti-central, randomized trial, moderate-to-very severe COPD subjects with a history of moderate-to-severe exacerbations in the previous year were enrolled and assigned in a ratio of 1:1:1:1 into 4 groups. All participants were managed based on the conventional treatment recommended by GOLD 2019 report for 3 months, with three groups receiving additional treatment of inhaled amikacin (0.4 g twice daily, 5-7 days monthly for 3 months), oral probiotic Lactobacillus rhamnosus GG (1 tablet daily for 3 months), or influenza-S. pneumoniae vaccination. The primary endpoint was time to the next onset of moderate-to-severe AECOPD from enrollment. Secondary endpoints included CAT score, mMRC score, adverse events, and survival in 12 months. Results: Among all 112 analyzed subjects (101 males, 96 smokers or ex-smokers, mean ± SD age 67.19 ± 7.39 years, FEV1 41.06 ± 16.09% predicted), those who were given dual vaccination (239.7 vs. 198.2 days, p = 0.044, 95%CI [0.85, 82.13]) and oral probiotics (248.8 vs. 198.2 days, p = 0.017, 95%CI [7.49, 93.59]) had significantly delayed onset of next moderate-to-severe AECOPD than those received conventional treatment only. For subjects with high symptom burden, the exacerbations were significantly delayed in inhaled amikacin group as compared to the conventional treatment group (237.3 vs. 179.1 days, p = 0.009, 95%CI [12.40,104.04]). The three interventions seemed to be safe and well tolerated for patient with stable COPD. Conclusion: The influenza-S. pneumoniae vaccine and long-term oral probiotic LGG can significantly delay the next moderate-to-severe AECOPD. Periodically amikacin inhalation seems to work in symptomatic patients. The findings in the current study warrants validation in future studies with microbiome investigation.Clinical trial registration:https://clinicaltrials.gov/, identifier NCT03449459.