MicroRNA-26b-5p promotes development of neonatal respiratory distress syndrome by inhibiting differentiation of mesenchymal stem cells to type II of alveolar epithelial cells via regulating Wnt5a

Nasal microRNA signatures for disease severity in infants with respiratory syncytial virus bronchiolitis: a multicentre prospective study

BACKGROUND

Respiratory syncytial virus (RSV) bronchiolitis contributes to a large morbidity and mortality burden globally. While emerging evidence suggests that airway microRNA (miRNA) is involved in the pathobiology of RSV infection, its role in the disease severity remains unclear.

METHODS

In this multicentre prospective study of infants (aged<1 year) hospitalised for RSV bronchiolitis, we sequenced the upper airway miRNA and messenger RNA (mRNA) at hospitalisation. First, we identified differentially expressed miRNAs (DEmiRNAs) associated with higher bronchiolitis severity-defined by respiratory support (eg, positive pressure ventilation, high-flow oxygen therapy) use. We also examined the biological significance of miRNAs through pathway analysis. Second, we identified differentially expressed mRNAs (DEmRNAs) associated with bronchiolitis severity. Last, we constructed miRNA-mRNA coexpression networks and determined hub mRNAs by weighted gene coexpression network analysis (WGCNA).

RESULTS

In 493 infants hospitalised with RSV bronchiolitis, 19 DEmiRNAs were associated with bronchiolitis severity (eg, miR-27a-3p, miR-26b-5p; false discovery rate<0.10). The pathway analysis using miRNA data identified 1291 bronchiolitis severity-related pathways-for example, regulation of cell adhesion mediated by integrin. Second, 1298 DEmRNAs were associated with bronchiolitis severity. Last, of these, 190 DEmRNAs were identified as targets of DEmiRNAs and negatively correlated with DEmiRNAs. By applying WGCNA to DEmRNAs, four disease modules were significantly associated with bronchiolitis severity-for example, microtubule anchoring, cell-substrate junction. The hub genes for each of these modules were also identified-for example, PCM1 for the microtubule anchoring module, LIMS1 for the cell-substrate junction module.

CONCLUSIONS

In infants hospitalised for RSV bronchiolitis, airway miRNA-mRNA coexpression network contributes to the pathobiology of bronchiolitis severity.

Novel insights into the potential applications of stem cells in pulmonary hypertension therapy

Pulmonary hypertension (PH) refers to a group of deadly lung diseases characterized by vascular lesions in the microvasculature and a progressive increase in pulmonary vascular resistance. The prevalence of PH has increased over time. Currently, the treatment options available for PH patients have limited efficacy, and none of them can fundamentally reverse pulmonary vascular remodeling. Stem cells represent an ideal seed with proven efficacy in clinical studies focusing on liver, cardiovascular, and nerve diseases. Since the potential therapeutic effect of mesenchymal stem cells (MSCs) on PH was first reported in 2006, many studies have demonstrated the efficacy of stem cells in PH animal models and suggested that stem cells can help slow the deterioration of lung tissue. Existing PH treatment studies basically focus on the paracrine action of stem cells, including protein regulation, exosome pathway, and cell signaling; however, the specific mechanisms have not yet been clarified. Apoptotic and afunctional pulmonary microvascular endothelial cells (PMVECs) and alveolar epithelial cells (AECs) are two fundamental promoters of PH although they have not been extensively studied by researchers. This review mainly focuses on the supportive communication and interaction between PMVECs and AECs as well as the potential restorative effect of stem cells on their injury. In the future, more studies are needed to prove these effects and explore more radical cures for PH.

Molecular Mechanisms Responsible for Therapeutic Potential of Mesenchymal Stem Cell-Derived Secretome

Mesenchymal stem cell (MSC)-sourced secretome, defined as the set of MSC-derived bioactive factors (soluble proteins, nucleic acids, lipids and extracellular vesicles), showed therapeutic effects similar to those observed after transplantation of MSCs. MSC-derived secretome may bypass many side effects of MSC-based therapy, including unwanted differentiation of engrafted MSCs. In contrast to MSCs which had to be expanded in culture to reach optimal cell number for transplantation, MSC-sourced secretome is immediately available for treatment of acute conditions, including fulminant hepatitis, cerebral ischemia and myocardial infarction. Additionally, MSC-derived secretome could be massively produced from commercially available cell lines avoiding invasive cell collection procedure. In this review article we emphasized molecular and cellular mechanisms that were responsible for beneficial effects of MSC-derived secretomes in the treatment of degenerative and inflammatory diseases of hepatobiliary, respiratory, musculoskeletal, gastrointestinal, cardiovascular and nervous system. Results obtained in a large number of studies suggested that administration of MSC-derived secretomes represents a new, cell-free therapeutic approach for attenuation of inflammatory and degenerative diseases. Therapeutic effects of MSC-sourced secretomes relied on their capacity to deliver genetic material, growth and immunomodulatory factors to the target cells enabling activation of anti-apoptotic and pro-survival pathways that resulted in tissue repair and regeneration.