Knockdown of versican 1 blocks cigarette-induced loss of insoluble elastin in human lung fibroblasts

Increased matrix metalloproteinase-2 in ligamentum flavum hypertrophy and the regulation of MMP-2/TIMPs by elastin-derived peptides

The study aimed to examine matrix metalloproteinase-2 (MMP-2) expression in a rat ligamentum flavum (LF) hypertrophy model in vivo, and the effect of elastin-derived peptides (EDPs) on MMP-2 and tissue inhibitors of metalloproteinases (TIMPs) in rat LF cells in vitro. Surgical destabilization was performed at the rat spinal L3/4 level to induce increased mechanical stress. Rats were killed at 6- and 12-weeks postsurgery for histological staining, immunohistochemical staining, RT-qPCR and western blot. 100 µg/mL EDPs were applied to isolated normal rat LF cells, with or without pretreatment of elastin receptor complex (ERC) inhibitors, to assess the expression of MMP-2, TIMP-1, and TIMP-2. Spinal destabilization led to LF hypertrophy, observed through increased LF thickness and area, along with histological changes of chondrometaplasia and elastic fiber degradation. LF was also stained positively for Col I and Col II, where elastic fiber has broken down. MMP-2 expression was notably elevated in the hypertrophied LF, accompanied by increased TIMP-2 and TIMP-3 levels. EDPs were found to suppress MMP-2 expression and reduce TIMP-1 and TIMP-2 levels in rat LF cells. Interestingly, exposure to EDPs led to a significant rise in MMP-2/TIMP-1 and MMP-2/TIMP-2 ratios, dependent on the ERC. Collectively, the study suggests that increased MMP-2 activity contributes to elastic fiber degradation in hypertrophied LF, generating EDPs that further enhance the MMP-2/TIMPs ratio in LF cells in an ERC-dependent manner. Further research is essential to delve into the mechanisms of EDPs in LF hypertrophy.

A Single-Cell Atlas of Small Airway Disease in Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study

Rationale: Emerging data demonstrate that the smallest conducting airways, terminal bronchioles, are the early site of tissue destruction in chronic obstructive pulmonary disease (COPD) and are reduced by as much as 41% by the time someone is diagnosed with mild (Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage 1) COPD. Objectives: To develop a single-cell atlas that describes the structural, cellular, and extracellular matrix alterations underlying terminal bronchiole loss in COPD. Methods: This cross-sectional study of 262 lung samples derived from 34 ex-smokers with normal lung function (n = 10) or GOLD stage 1 (n = 10), stage 2 (n = 8), or stage 4 (n = 6) COPD was performed to assess the morphology, extracellular matrix, single-cell atlas, and genes associated with terminal bronchiole reduction using stereology, micro-computed tomography, nonlinear optical microscopy, imaging mass spectrometry, and transcriptomics. Measurements and Main Results: The lumen area of terminal bronchioles progressively narrows with COPD severity as a result of the loss of elastin fibers within alveolar attachments, which was observed before microscopic emphysematous tissue destruction in GOLD stage 1 and 2 COPD. The single-cell atlas of terminal bronchioles in COPD demonstrated M1-like macrophages and neutrophils located within alveolar attachments and associated with the pathobiology of elastin fiber loss, whereas adaptive immune cells (naive, CD4, and CD8 T cells, and B cells) are associated with terminal bronchiole wall remodeling. Terminal bronchiole pathology was associated with the upregulation of genes involved in innate and adaptive immune responses, the interferon response, and the degranulation of neutrophils. Conclusions: This comprehensive single-cell atlas highlights terminal bronchiole alveolar attachments as the initial site of tissue destruction in centrilobular emphysema and an attractive target for disease modification.

Knockdown of versican 1 in lung fibroblasts aggravates Lipopolysaccharide-induced acute inflammation through up-regulation of the SP1-Toll-like Receptor 2-NF-κB Axis: a potential barrier to promising Versican-targeted therapy

OBJECTIVE

Versican participates in various pathological processes like inflammation and fibrosis and is a potential therapeutic target for inflammatory diseases. Versican 1 (V1) has increased expression in inflammatory diseases, but its role is unclear. We explored the effects of V1 on acute lung inflammation to determine whether targeting V1 had therapeutic potential.

METHODS

Human fetal lung fibroblast (HFL1) was transfected with or without V1-inhibiting lentivirus and treated with LPS. The expression levels of inflammatory cytokines, V1, cellular signaling pathway and Toll-like receptors (TLRs) were detected by qPCR, ELISA and western blot. The migration and adhesion of neutrophils and monocytes to HFL1s were performed. The activity of transcriptional factors was determined by dual-luciferase reporter assay.

RESULTS

Inflammatory factors increased dramatically and continuously with V1 knockdown and LPS stimulation (P < 0.01), orchestrating migration of inflammatory cells and an enhanced inflammatory reaction. V1-knockdown increased TLR2 (P < 0.01) and activated the NF-κB pathway, which was partially reversed with a TLR2 neutralizing antibody and an NF-κB inhibitor. Explosion of LPS-induced inflammation was induced by knockdown of V1 via the SP1-TLR2-NF-κB axis.

CONCLUSION

Increased expression of V1 might be protective in acute inflammation, and an infection-induced cytokine storm might be a severe complication of V1-targeted interventions.

p53 Signaling Pathway Polymorphisms Associated With Emphysematous Changes in Patients With COPD

BACKGROUND

The p53 signaling pathway may be important for the pathogenesis of emphysematous changes in the lungs of smokers. Polymorphism of p53 at codon 72 is known to affect apoptotic effector proteins, and the polymorphism of mouse double minute 2 homolog (MDM2) single nucleotide polymorphism (SNP)309 is known to increase MDM2 expression. The aim of this study was to assess polymorphisms of the p53 and MDM2 genes in smokers and confirm the role of SNPs in these genes in the pathogenesis of pulmonary emphysema.

METHODS

This study included 365 patients with a smoking history, and the polymorphisms of p53 and MDM2 genes were identified. The degree of pulmonary emphysema was determined by means of CT scanning. SNPs, MDM2 mRNA, and p53 protein levels were assessed in human lung tissues from smokers. Plasmids encoding p53 and MDM2 SNPs were used to transfect human lung fibroblasts (HLFs) with or without cigarette smoke extract (CSE), and the effects on cell proliferation and MDM2 promoter activity were measured.

RESULTS

The polymorphisms of the p53 and MDM2 genes were associated with emphysematous changes in the lung and were also associated with p53 protein and MDM2 mRNA expression in the lung tissue samples. Transfection with a p53 gene-coding plasmid regulated HLF proliferation, and the analysis of P2 promoter activity in MDM2 SNP309-coding HLFs showed the promoter activity was altered by CSE.

CONCLUSIONS

Our data demonstrated that p53 and MDM2 gene polymorphisms are associated with apoptotic signaling and smoking-related emphysematous changes in lungs from smokers.