RhoA regulates lipopolysaccharide‑induced lung cell injury via the Wnt/β‑catenin pathway

Mechanism and application of feedback loops formed by mechanotransduction and histone modifications

Mechanical stimulation is the key physical factor in cell environment. Mechanotransduction acts as a fundamental regulator of cell behavior, regulating cell proliferation, differentiation, apoptosis, and exhibiting specific signature alterations during the pathological process. As research continues, the role of epigenetic science in mechanotransduction is attracting attention. However, the molecular mechanism of the synergistic effect between mechanotransduction and epigenetics in physiological and pathological processes has not been clarified. We focus on how histone modifications, as important components of epigenetics, are coordinated with multiple signaling pathways to control cell fate and disease progression. Specifically, we propose that histone modifications can form regulatory feedback loops with signaling pathways, that is, histone modifications can not only serve as downstream regulators of signaling pathways for target gene transcription but also provide feedback to regulate signaling pathways. Mechanotransduction and epigenetic changes could be potential markers and therapeutic targets in clinical practice.

Differential expression profile of plasma exosomal microRNAs in acute type A aortic dissection with acute lung injury

MicroRNAs (miRNAs) packaged into exosomes mediate cell communication and contribute to the pathogenesis of acute type A aortic dissection (ATAAD) with acute lung injury (ALI). The expression profile of plasma exosomal miRNAs in ATAAD patients with ALI hasn’t been identified. We performed a miRNA-sequencing to analyze the differentially expressed miRNAs (DE-miRNAs) of circulating exosomes in ATAAD patients with ALI compared to patients without ALI, founding 283 specific miRNAs in two groups. We respectively selected the top 10 downregulated and upregulated DE-miRNAs for further studies. The predicted transcription factors (TFs) of these DE-miRNAs were SMAD2, SRSF1, USF1, etc. The Gene Ontology (GO) and Kyoto Encyclopedia Genes and Genomes (KEGG) analysis predicted their target genes mainly involved acute inflammatory response, cell junction, cytoskeleton, NF-κB signaling pathway, etc. Construction and analysis of the PPI network revealed that RHOA and INSR were considered hub genes with the highest connectivity degrees. Moreover, we confirmed two exosomal miRNAs (hsa-miR-485-5p and hsa-miR-206) by real-time quantitative polymerase chain reaction (RT-qPCR) in a validation cohort. Our study identified a plasma exosomal miRNAs signature related to ATAAD with ALI. Certain DE-miRNAs may contribute to the progression of this disease, which help us better understand the pathogenesis of ATAAD with ALI.

The expression profile of lung long non-coding RNAs and mRNAs in a mouse model of smoke inhalation injury

To study the potential expression of lung long non-coding RNAs (lncRNAs) and mRNAs during smoke inhalation injury (SII), using a SII mouse model that we created in our previous work. Microarray was used to investigate the lncRNAs and mRNAs profiles. A bioinformatics analysis was performed. Changes in the top 10 down-regulated and 10 up-regulated lncRNAs were validated using Quantitative Reverse Transcription-PCR (RT-qPCR). The acute lung injury (ALI) mouse model was successfully induced by smoke inhalation, as confirmed by the aberrantly modified cell numbers of red blood cells and neutrophils counts, increased levels of TNF-α, IL-1β, Bax, caspase-7, caspase-3, and decreased Bcl-2 content in lung tissues. When compared to the control mice, 577 lncRNAs and 517 mRNAs were found to be aberrantly expressed in the SII mice. According to the Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, the altered mRNAs were enriched in acute-phase response, oxidoreductase activity, oxidation-reduction process, glutathione metabolism, the wnt signaling pathway, and ferroptosis. A lncRNA-related competitive endogenous RNA (ceRNA) network, including 383 lncRNAs, 318 MicroRNAs (miRNAs), and 421 mRNAs specific to SII, was established. The changes in NONMMUT026843.2, NONMMUT065071.2, ENSMUST00000235858.1, NONMMUT131395.1, NONMMUT122516.1, NONMMUT057916.2, and NONMMUT013388.2 in the lung matched the microarray results. Our findings help to provide a more comprehensive understanding of the pathogenesis of SII as well as new insights into potential therapeutic targets.

ETS1 Ameliorates Hyperoxia-Induced Alveolar Epithelial Cell Injury by Regulating the TGM2-Mediated Wnt/β-Catenin Pathway

PURPOSE

Bronchopulmonary dysplasia (BPD) is a chronic lung disease that affects newborns who need oxygen therapy, and high-concentration oxygen therapy may cause neonatal morbidity and mortality in newborns. E26 oncogene homologue 1 (ETS1) and transglutaminase 2 (TGM2) have been reported to be associated with lung cell injury. However, the mechanism of ETS1 in regulating BPD is still unclear.

METHODS

Hyperoxia-induced A549 cells to simulate hyperoxia-induced alveolar epithelial cell injury. MTT assays and colony formation assays were performed to investigate the proliferation of A549 cells. Flow cytometry was carried out to quantify the apoptosis of A549 cells. The expression levels of ETS1 and TGM2 were quantified by qRT-PCR. The protein expression levels of ETS1, TGM2, β-catenin, c-Jun and MET were measured by western blot. Overexpression of ETS1, overexpression of TGM2, overexpression of ETS1 with downregulation of TGM2 and overexpression of TGM2 with inhibition of Wnt/β-catenin pathway were performed to investigate the role of ETS1, TGM2 and Wnt/β-catenin pathways in hyperoxia-induced alveolar epithelial cell injury.

RESULTS

Hyperoxia decreased the proliferation and promoted the apoptosis of cells in a time-dependent manner. Moreover, overexpression of ETS1 rescued the effect of hyperoxia on proliferation and apoptosis. In addition, overexpression of TGM2 participated in the regulation of hyperoxia-induced proliferation and apoptosis. ETS1 regulated hyperoxia-induced alveolar epithelial cell injury through the Wnt/β-catenin pathway via TGM2.

CONCLUSION

ETS1 ameliorates hyperoxia-induced alveolar epithelial cell injury through the TGM2-mediated Wnt/β-catenin pathway.

SU5416 attenuated lipopolysaccharide-induced acute lung injury in mice by modulating properties of vascular endothelial cells

Background and aim: A potent and selective vascular endothelial growth factor receptor (VEGFR) inhibitor SU5416, has been developed for the treatment of solid human tumors. The binding of VEGF to VEGFR plays a crucial role in the pathophysiology of respiratory disorders. However, the impact of SU5416 on lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains unclear. Thus, this study aimed to illuminate the biofunction of SU5416 in the mouse model of ALI.

Methods: Wild-type (WT) and toll-like receptor 4 (TLR4)-deficient (TLR4^−/-) C57BL/6 mice were used to establish LPS-induced ALI model. The primary pulmonary microvascular endothelial cell (PMVEC) was extracted for detection of endothelial barrier function.

Results: LPS significantly increased the number of inflammatory cells and inflammatory cytokines in bronchoalveolar lavage fluid (BALF). In addition, LPS increased alveolar epithelial cells injury, inflammation infiltration and vascular permeability of PMVEC in WT and TLR4^−/- mice. Western blotting experiment indicated VEGF/VEGFR and TLR4/NF-κB pathways were involved in the progression of LPS-stimulated ALI. Consistent with previous research, dexamethasone treatment appeared to be an effective therapeutic for mice with ALI. Moreover, treatment with SU5416 dramatically attenuated LPS-induced immune responses in mice lung tissues via inhibiting VEGF/VEGFR and TLR4/NF-κB pathways. Finally, SU5416 also decreased vascular permeability of PMVEC in vitro.

Conclusion: SU5416 ameliorated alveolar epithelial cells injury and histopathological changes in mice lung via inhibiting VEGF/VEGFR and TLR4/NF-κB signaling pathways. We also confirmed that SU5416 could restrain vascular permeability in PMVEC through improving the integrity of endothelial cell. These findings suggested that SU5416 may serve as a potential agent for the treatment of patients with ALI.

Microarray analysis reveals the changes of circular RNA expression and molecular mechanism in acute lung injury mouse model

Acute lung injury (ALI) is a severe disease with sudden onset, rapid progression, poor treatment response, and high mortality. An increasing number of studies had found that circular RNAs (circRNAs) has significant functions in various diseases, while the role of circRNAs in ALI is not yet clear. The purpose of this study was to find circRNAs related to ALI and their mechanism of action. Expression profiles of lung circRNAs and messenger RNAs (mRNAs) were analyzed by microarray in the ALI mice models and healthy controlled mice. Differentially expressed RNAs were identified, function and pathways were analyzed by bioinformatics analysis. Moreover, the results of the microarray were verified by real-time PCR. We identified 2262 differentially expressed mRNAs and 581 circRNAs between ALI mice and control. Validation of candidate circRNAs by real-time PCR indicates that the majority of circRNAs identified by microarray are reliable and worthy of further study. ALI induced circRNAs primarily function in the metabolic regulatory process. Moreover, differentially expressed circRNAs were mainly involved in signaling pathways of mitogen-activated protein kinases, focal adhesion, FoxO, neurotrophin, and Wnt. In addition, a competitive endogenous RNA network was constructed to further interpret the molecular mechanism of ALI. This study observed significantly changed circRNAs profiles in LPS-induced mouse model and revealed a potential role of circRNAs in ALI.