Regulation of airway immunity by epithelial miRNAs

Epithelialized chimeric repairing patch supports in situ healing of tracheal fistula

Tracheal fistula (TF) is a severe thoracic disease characterized by high mortality rates, and current treatment methods present substantial risks while presenting challenges in reepithelialization. In this study, we developed a chimeric repairing patch (CRP) featuring a double-disc structure, designed to seal TF defects and promote organized tissue regeneration. The CRP incorporates a double-cross-linking silk fibroin network and hierarchical micropores, resulting in a flexible, hydrophilic, and biocompatible patch with tissue-matching mechanical properties. The CRP could effectively seal defects and encourage tissue ingrowth, successfully repairing TF. A tissue-engineered epithelialized CRP (E-CRP) was further developed to enhance in situ reepithelialization. The CRP demonstrated reliable structural stability and facilitated effective tissue regeneration and functional reconstruction of TF defects in a large animal model. Furthermore, the customized CRPs might be preloaded into a bronchoscope and precisely delivered to TF defects via noninvasive implantation. Consequently, the proposed CRP/E-CRP represents a promising scaffold for TF treatment, with substantial transformative potential in clinical practice.

Extracellular vesicles from PBDE-47 treated M(LPS) THP-1 macrophages modulate the expression of markers of epithelial integrity, EMT, inflammation and muco-secretion in ALI culture of airway epithelium

AIMS

The lung epithelial cells form a physical barrier to the external environment acting as the first line of defence against potentially harmful environmental stimuli. These cells interact with several other cellular components, of which macrophages are some of the most relevant. We analysed the effects of the PBDE-47 on the microRNA cargo of THP-1 macrophage like derived small Extracellular Vesicles (sEVs) and the effects on A549 lung epithelial cells.

MAIN METHODS

sEVs from M(LPS) THP-1 macrophage-like cells after PBDE-47 treatment (sEVs^PBDE+LPS) were characterized by nanoparticle tracking analysis and their microRNA cargo studied by qPCR. Confocal microscopy was applied to study sEVs cellular uptake by A549 cells. The expression of tight junctions (TJs), adhesion molecules, inflammation markers and mucus production in A549 cultured in air liquid interface (ALI) conditions were studied by Real Time PCR and confocal microscopy.

KEY FINDINGS

sEVs^PBDE+LPS microRNA cargo analysis showed that the PBDE-47 modulated the expression of the miR-15a-5p, miR29a-3p, miR-143-3p and miR-122-5p. Furthermore, ALI cultured A549 cells incubated with sEVs^PBDE+LPS showed that zonula occludens-1 (p ≤ 0.04), claudin (p ≤ 0.02), E-cadherin (p ≤ 0.006) and Vimentin (p ≤ 0.0008) mRNAs were increased in A549 cells after sEVs^PBDE+LPS treatment. Indeed, Interleukin (IL)-8 (p ≤ 0.008) and mucin (MUC5AC and MUC5B) (p ≤ 0.03 and p ≤ 0.0001) mRNA expression were up- and down-regulated, respectively.

SIGNIFICANCE

PBDE-47 treated macrophages secrete sEVs with altered microRNA cargo that affect the mRNA expression of TJs, adhesion molecules, cytokines and EMT markers damaging the normal function of the lung epithelium, potentially contributing to the development of lung diseases.