Roles of different mitochondrial electron transport chain complexes in hypoxia-induced pulmonary vasoconstriction

Bioinformatic Analysis and Cellular Assays Identify Substance P Influencing Th17/Treg Differentiation via the MyD88 Pathway as a Potential Contributor to the Progression of Asthma and Allergic Rhinitis

Objective

This study is aimed at investigating the role of substance P (SP) in the development of asthma.

Methods

The Gene Expression Omnibus (GEO) database was used to characterize SP expression in allergic rhinitis (AR) and asthma. Peripheral blood was collected from patients with asthma or AR. The expression of relevant cytokines and neuropeptides was measured. Enzyme-linked immunosorbent assay (ELISA) was also performed. The mast cell line LAD2 and the lung bronchial epithelial cell line BEAS-2B were treated with different concentrations of SP concentration. Then, the qRT-PCR method was used to determine the mRNA expression. Furthermore, p38 and p65 and their associated phosphorylated proteins (p-p38 and p-p65) were further validated by western blotting.

Result

Clinical and GSE75011 data analysis suggested that MyD88 expression was upregulated in AR and asthma. Through the gene set variation analysis (GSVA), MyD88-related pathways were noticed and further investigated. ELISA results suggested that the SP expression was significantly increased in AR and asthma and IL-10 expression was decreased, whereas the expression of IL-6, IL-17A, IL-23, and TGF-β expressions increased. The mast cell line LAD2 was treated with different SP concentrations, and ELISA results showed that the expression of IL-6, IL-17A, IL-23, and TGF-β in the cell supernatant gradually increased with increasing SP concentrations, whereas that of IL-10 decreased. The lung bronchial epithelial cell line BEAS-2B was treated with different SP concentrations, and the expression of myeloid differentiation factor 88 (MyD88) and its related proteins was elevated. The expression of p38 and p-p38 proteins was elevated after SP treatment, and their expression levels elevated as SP concentrations increased. Finally, MyD88 expression at the single-cell level was also demonstrated.

Conclusion

SP may affect the cytokine expression through the MyD88 pathway, thereby influencing Th17/Treg differentiation and eventually participating in the pathological process of asthma and AR. There are many pathological similarities between allergic rhinitis (AR) and bronchial asthma. In the present study, SP was found to possibly activate downstream inflammatory signaling pathways via MyD88, thereby affecting Th17/Treg differentiation and ultimately participating in the pathological process of asthma and AR.

Long non-coding RNA TUG1 knockdown promotes autophagy and improves acute renal injury in ischemia-reperfusion-treated rats by binding to microRNA-29 to silence PTEN

Objective

Long noncoding RNA (lncRNA) taurine upregulated gene 1 (TUG1) is increased under the condition of ischemia. This study intended to identify the mechanism of TUG1 in renal ischemia-reperfusion (I/R).

Methods

First, a rat model of acute renal injury induced by I/R was established, followed by the measurement of blood urea nitrogen (BUN), serum creatine (SCr), methylenedioxyphetamine (MDA) and superoxide dismutase (SOD) in the serum of rats. TUG1 was knocked down in I/R rats (ko-TUG1 group). Next, histological staining was used to evaluate the pathological damage and apoptosis of rat kidney. Western blot analysis was used to detect the levels of apoptosis- and autophagy-related proteins and transmission electron microscope was used to observe autophagosomes. Autophagy and apoptosis were evaluated after inhibition of the autophagy pathway using the inhibitor 3-MA. The targeting relation among TUG1, microRNA (miR)-29 and phosphatase and tensin homolog (PTEN) were validated. Lastly, the effects of TUG1 on biological behaviors of renal tubular cells were evaluated in vitro.

Results

In vivo, the levels of BUN, SCr and MDA in the serum of I/R-treated rats were increased while SOD level and autophagosomes were reduced, tubule epithelial cells were necrotic, and TUG1 was upregulated in renal tissues of I/R-treated rats, which were all reversed in rats in the ko-TUG1 group. Autophagy inhibition (ko-TUG1 + 3-MA group) averted the protective effect of TUG1 knockdown on I/R-treated rats. TUG1 could competitively bind to miR-29 to promote PTEN expression. In vitro, silencing TUG1 (sh-TUG1 group) promoted viability and autophagy of renal tubular cells and inhibited apoptosis.

Conclusions

LncRNA TUG can promote PTEN expression by competitively binding to miR-29 to promote autophagy and inhibited apoptosis, thus aggravating acute renal injury in I/R-treated rats.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02473-0.

Transcriptomic analyses of the biological effects of black carbon exposure to A549 cells

Ambient black carbon (BC) is found to be associated with increased risk of diverse pulmonary diseases, including acute respiratory inflammation and decreased lung function. Freshly emitted BC (FBC) can be transformed into oxidized BC (OBC) through the photochemical oxidization in the air. How this oxidization process influences the toxicity of BC particles is unclear. Previous studies found FBC and OBC could induce oxidative stress and inflammation. This study aimed to further compare the regulating pathways and tried to reveal the crucial target genes caused by FBC and OBC in A549 cells based on transcriptomic data. A total of 47,000 genes in A549 cells after treated with FBC and OBC were examined using Affymetrix Human U133 plus 2.0 chips. Gene ontology (GO) classification (functional enrichment of differentially expressed genes) and Kyoto encyclopedia of genes and genomes (KEGG) classification (pathway enrichment of differentially expressed genes) were conducted and crucial genes were screened. The results showed that top 50 GO terms of FBC and OBC were not completely consistent. The Go term of cation channel was only identified in OBC group, probably caused by the characteristic that zeta potential of OBC is negative, while, that of FBC is positive. In addition transient receptor potential melastatin 7 (trpm7) gene was suggested to be closely related to this process caused by OBC. There are 47 identical pathways in FBC and OBC group among the top 50 KEGG. The inconsistent pathways are mostly related to inflammation with different up-regulation or down-regulation trends of crucial genes. The KEGG results suggested that FBC and OBC both cause inflammatory responses, but through different regulating pathways. In conclusion, OBC and FBC could induce similar toxic endpoints in A549 cells, but the underline regulating processes are not exactly the same.

Sensors and signals: the role of reactive oxygen species in hypoxic pulmonary vasoconstriction

When lung cells experience hypoxia, the functional response, termed hypoxic pulmonary vasoconstriction, activates a multitude of pathways with the goal of optimizing gas exchange. While previously controversial, overwhelming evidence now suggests that increased reactive oxygen species - produced at complex III of the mitochondrial electron transport chain and released into the intermembrane space - is the cellular oxygen signal responsible for triggering hypoxic pulmonary vasoconstriction. The increased reactive oxygen species (ROS) activate many downstream targets that ultimately lead to increased intracellular ionized calcium concentration and contraction of pulmonary arterial smooth muscle cells. While the specific targets of ROS signals are not completely understood, it is clear that this signalling pathway is critical for development and for normal lung function in newborns and adults.

Gestational Hypoxia and Developmental Plasticity

Hypoxia is one of the most common and severe challenges to the maintenance of homeostasis. Oxygen sensing is a property of all tissues, and the response to hypoxia is multidimensional involving complicated intracellular networks concerned with the transduction of hypoxia-induced responses. Of all the stresses to which the fetus and newborn infant are subjected, perhaps the most important and clinically relevant is that of hypoxia. Hypoxia during gestation impacts both the mother and fetal development through interactions with an individual's genetic traits acquired over multiple generations by natural selection and changes in gene expression patterns by altering the epigenetic code. Changes in the epigenome determine "genomic plasticity," i.e., the ability of genes to be differentially expressed according to environmental cues. The genomic plasticity defined by epigenomic mechanisms including DNA methylation, histone modifications, and noncoding RNAs during development is the mechanistic substrate for phenotypic programming that determines physiological response and risk for healthy or deleterious outcomes. This review explores the impact of gestational hypoxia on maternal health and fetal development, and epigenetic mechanisms of developmental plasticity with emphasis on the uteroplacental circulation, heart development, cerebral circulation, pulmonary development, and the hypothalamic-pituitary-adrenal axis and adipose tissue. The complex molecular and epigenetic interactions that may impact an individual's physiology and developmental programming of health and disease later in life are discussed.