Infection of influenza A virus (IAV) can trigger exaggerated pulmonary inflammation and induce acute lung injury (ALI). Limiting IAV replication and alleviation of pulmonary inflammation are two ...important therapeutic strategies for influenza virus infection. Recent studies have shown that hypoxia inducible factor-1α (HIF-1α) is an essential factor for the development and repair of ALI; however, the role and the underlying mechanisms of HIF-1α in IAV-induced ALI remain elusive. Here, we demonstrated that lung epithelial cell-specific Hif1α knockout mice infected with IAV developed more lung IAV replication and severe lung inflammation, which led to increased mortality compared to IAV-infected control mice. Moreover, knockdown of HIF1A in A549 cells (human alveolar type II epithelial cell line) promoted IAV replication in vitro. Mechanistically, knockdown of HIF1A reduced glycolysis by regulating transcription of glycolysis-related enzymes, which subsequently activated the AMPKα-ULK1 signalling pathway. Interestingly, AMPKα-ULK1 signalling promoted autophagy and augmented IAV replication. Taken together, deficiency of HIF-1α in lung epithelial cells reduces glycolysis and enhances AMPKα-ULK1-mediated autophagy, which finally facilitates IAV replication. These findings have deepened our understanding of the role of HIF-1α in regulating IAV replication and provided us novel therapeutic targets for combating influenza infection.
Proliferation and transdifferentiation of lung stem cells (LSCs) could promote lung injury repair. The distal airways of the lung are innervated by the vagus nerve. Vagal-alpha7 nicotinic ...acetylcholine receptor (α7nAChR) signaling plays a key role in regulating lung infection and inflammation; however, whether this pathway could regulate LSCs remains unknown.
LSCs (Sca1
CD45
CD31
cells) were isolated and characterized according to a previously published protocol. α7nAChR knockout mice and wild-type littermates were intratracheally challenged with lipopolysaccharide (LPS) to induce lung injury. A cervical vagotomy was performed to study the regulatory effect of the vagus nerve on LSCs-mediated lung repair. α7nAChR agonist or fibroblast growth factor 10 (FGF10) was intratracheally delivered to mice. A single-cell suspension of lung cells was analyzed by flow cytometry. Lung tissues were collected for histology, quantitative real-time polymerase chain reaction (RT-PCR), and immunohistochemistry.
We found that LSCs maintained multilineage differentiation ability and transdifferentiated into alveolar epithelial type II cells (AEC2) following FGF10 stimulation in vitro. Vagotomy or α7nAChR deficiency reduced lung Ki67
LSCs expansion and hampered the resolution of LPS-induced lung injury. Vagotomy or α7nAChR deficiency decreased lung FGF10 expression and the number of AEC2. The α7nAChR agonist-GTS-21 reversed the reduction of FGF10 expression in the lungs, as well as the number of Ki67
cells, LSCs, Ki67
LSCs, and AEC2 in LPS-challenged vagotomized mice. Supplementation with FGF10 counteracted the loss of Ki67
LSCs and AEC2 in LPS-challenged α7nAChR knockout mice.
The vagus nerve deploys α7nAChR to enhance LSCs proliferation and transdifferentiation and promote lung repair in an FGF10-dependent manner during LPS-induced lung injury.
•The effect of stacking fault energy on Cu–Al–Zn alloys was investigated.•The strength and ductility of the samples increased with decreasing SFE.•A decrease in SFE leads to smaller grains and higher ...dislocation and twin densities.•Twinning becomes a more important role that could improve the ductility and strength.•The experimental results are consistent with a theoretical model by Mohamed.
Cu–2.5at.% Al–2.5at.% Zn, Cu–4.5at.% Al–22.8at.% Zn and Cu–12.1at.% Al–4.1at.% Zn alloys with stacking fault energies (SFEs) of 40, 10, and 7mJ/m2, respectively, were processed by combination of room temperature rolling (RR) and liquid nitrogen temperature rolling (LNR). The effect of SFE on microstructure refinement and mechanical properties of these materials were investigated. Microstructural observations indicate that a decrease in SFE leads to a decrease in crystallite size and to increase in microstrain, dislocation and twin densities for the RR and LNR samples. The results show that under the same deformation conditions, lower SFE promotes the formation of nanostructures and deformation twins. An analysis shows that the experimental results are consistent with a theoretical model which predicted the minimum grain size produced by milling.
Tensile and stress relaxation experiments were used to study the mechanical properties and deformation kinetics of Cu–12.1at%Al–4.1at%Zn alloy processed by cold rolling and followed annealing. ...Samples rolled at liquid nitrogen temperature exhibit higher tensile strength and better ductility compared to the ones rolled at room temperature, and the low temperature annealing resulted in an increase of the strength for all as-rolled samples. The analysis of strain rate sensitivity, activation volume and mobile dislocations indicates that the thermally activated deformation mechanism in the as-rolled and low temperature annealed samples is different from that of the coarse grains.
The effects of stacking fault energy (SFE) and severe plastic deformation on the strength and ductility of Cu and Cu–Al–Zn alloys were systematically investigated. With lowering SFE, the crystallite ...size decreased while the microstrain, dislocation density and twin density all increased. Tensile testing results demonstrate that the tensile strength and uniform elongation increase with decreasing SFE, but the total elongation to failure first decreases with lowering SFE and then increases. The relationship between microstructure and mechanical behavior is briefly discussed in the paper.
The formation of large necrotic cores results in vulnerable atherosclerotic plaques, which can lead to severe cardiovascular diseases. However, the specific regulatory mechanisms underlying the ...development of necrotic cores remain unclear.
To evaluate how the modes of lesional cell death are reprogrammed during the development of atherosclerosis, the expression levels of key proteins that are involved in the necroptotic, apoptotic, and pyroptotic pathways were compared between different stages of plaques in humans and mice. Luciferase assays and loss-of-function studies were performed to identify the microRNA-mediated regulatory mechanism that protects foamy macrophages from necroptotic cell death. The role of this mechanism in atherosclerosis was determined by using a knockout mouse model with perivascular drug administration and tail vein injection of microRNA inhibitors in
mice.
Here, we demonstrate that the necroptotic, rather than the apoptotic or pyroptotic, pathway is more activated in advanced unstable plaques compared with stable plaques in both humans and mice, which closely correlates with necrotic core formation. The upregulated expression of Ripk3 (receptor-interacting protein kinase 3) promotes the C/EBPβ (CCAAT/enhancer binding protein beta)-dependent transcription of the microRNA miR-223-3p, which conversely inhibits Ripk3 expression and forms a negative feedback loop to regulate the necroptosis of foamy macrophages. The knockout of the
gene in bone marrow cells accelerates atherosclerosis in
mice, but this effect can be rescued by
deficiency or treatment with the necroptosis inhibitors necrostatin-1 and GSK-872. Like the
knockout, treating
mice with miR-223-3p inhibitors increases atherosclerosis.
Our study suggests that miR-223-3p expression in macrophages protects against atherosclerotic plaque rupture by limiting the formation of necrotic cores, thus providing a potential microRNA therapeutic candidate for atherosclerosis.
Andrographolide, the main active component extracted from Andrographis paniculata (Burm.f.) Wall. ex Nees, exerts anti-inflammatory effects; however, the principal molecular mechanisms remain ...unclear. The objective of this study was to investigate the molecular mechanisms of Andrographolide in modifying lipopolysaccharide- (LPS-) induced signaling pathway in RAW264.7 cells. An in vitro model of inflammation was induced by LPS in mouse RAW264.7 cells in the presence of Andrographolide. The concentration and expression levels of proinflammatory cytokines were determined by an enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. The nuclear level of NF-κB was measured by an electrophoretic mobility shift assay (EMSA). The expression levels of NF-κB, p38, ERK, and JNK were determined by western blot. Andrographolide dose-dependently inhibited the release and mRNA expression of TNF-α, IL-6, and IL-1β in LPS-stimulated RAW264.7 cells. The nuclear level of p65 protein was decreased in Andrographolide treatment group. Western blot analysis showed that Andrographolide suppressed LPS-induced NF-κB activation and the phosphorylation of IkBa, ERK1/2, JNK, and p38. These results suggest that Andrographolide exerts an anti-inflammatory effect by inhibiting the activation of NF-κB/MAPK signaling pathway and the induction of proinflammatory cytokines.
Vagus nerve regulates viral infection and inflammation via the alpha 7 nicotinic acetylcholine receptor (α7 nAChR); however, the role of α7 nAChR in ZIKA virus (ZIKV) infection, which can cause ...severe neurological diseases such as microcephaly and Guillain-Barré syndrome, remains unknown. Here, we first examined the role of α7 nAChR in ZIKV infection in vitro. A broad effect of α7 nAChR activation was identified in limiting ZIKV infection in multiple cell lines. Combined with transcriptomics analysis, we further demonstrated that α7 nAChR activation promoted autophagy and ferroptosis pathways to limit cellular ZIKV viral loads. Additionally, activation of α7 nAChR prevented ZIKV-induced p62 nucleus accumulation, which mediated an enhanced autophagy pathway. By regulating proteasome complex and an E3 ligase NEDD4, activation of α7 nAChR resulted in increased amount of cellular p62, which further enhanced the ferroptosis pathway to reduce ZIKV infection. Moreover, utilizing in vivo neonatal mouse models, we showed that α7 nAChR is essential in controlling the disease severity of ZIKV infection. Taken together, our findings identify an α7 nAChR-mediated effect that critically contributes to limiting ZIKV infection, and α7 nAChR activation offers a novel strategy for combating ZIKV infection and its complications.
Display omitted
Su and colleagues find that activation of α7 nAChR significantly limits ZIKV infection by enhancing autophagy and ferroptosis. Moreover, α7 nAChR is essential to control ZIKV-induced disease severity in neonatal mice. Harnessing α7 nAChR activation holds promising potential as a novel strategy to combat ZIKV infection and its associated complications.
Background Proliferation and transdifferentiation of lung stem cells (LSCs) could promote lung injury repair. The distal airways of the lung are innervated by the vagus nerve. Vagal-alpha7 nicotinic ...acetylcholine receptor (alpha7nAChR) signaling plays a key role in regulating lung infection and inflammation; however, whether this pathway could regulate LSCs remains unknown. Methods LSCs (Sca1.sup.+CD45.sup.-CD31.sup.- cells) were isolated and characterized according to a previously published protocol. alpha7nAChR knockout mice and wild-type littermates were intratracheally challenged with lipopolysaccharide (LPS) to induce lung injury. A cervical vagotomy was performed to study the regulatory effect of the vagus nerve on LSCs-mediated lung repair. alpha7nAChR agonist or fibroblast growth factor 10 (FGF10) was intratracheally delivered to mice. A single-cell suspension of lung cells was analyzed by flow cytometry. Lung tissues were collected for histology, quantitative real-time polymerase chain reaction (RT-PCR), and immunohistochemistry. Results We found that LSCs maintained multilineage differentiation ability and transdifferentiated into alveolar epithelial type II cells (AEC2) following FGF10 stimulation in vitro. Vagotomy or alpha7nAChR deficiency reduced lung Ki67.sup.+ LSCs expansion and hampered the resolution of LPS-induced lung injury. Vagotomy or alpha7nAChR deficiency decreased lung FGF10 expression and the number of AEC2. The alpha7nAChR agonist-GTS-21 reversed the reduction of FGF10 expression in the lungs, as well as the number of Ki67.sup.+ cells, LSCs, Ki67.sup.+ LSCs, and AEC2 in LPS-challenged vagotomized mice. Supplementation with FGF10 counteracted the loss of Ki67.sup.+ LSCs and AEC2 in LPS-challenged alpha7nAChR knockout mice. Conclusions The vagus nerve deploys alpha7nAChR to enhance LSCs proliferation and transdifferentiation and promote lung repair in an FGF10-dependent manner during LPS-induced lung injury. Keywords: Vagus nerve, Lung stem cells (LSCs), Multipotential differentiation, Proliferation
Andrographolide, the main active component extracted from Andrographis paniculata (Burm.f.) Wall. ex Nees, exerts antiinflammatory effects; however, the principal molecular mechanisms remain unclear. ...The objective of this study was to investigate the molecular mechanisms of Andrographolide in modifying lipopolysaccharide- (LPS-) induced signaling pathway in RAW264.7 cells. An in vitro model of inflammation was induced by LPS in mouse RAW264.7 cells in the presence of Andrographolide. The concentration and expression levels of proinflammatory cytokines were determined by an enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. The nuclear level of NF-kappaB was measured by an electrophoretic mobility shift assay (EMSA). The expression levels of NF- kappaB, p38, ERK, and JNK were determined by western blot. Andrographolide dose-dependently inhibited the release and mRNA expression of TNF-alpha, IL-6, and IL-1beta in LPS-stimulated RAW264.7 cells. The nuclear level of p65 protein was decreased in Andrographolide treatment group. Western blot analysis showed that Andrographolide suppressed LPS-induced NF-kappaB activation and the phosphorylation of IkBa, ERK1/2, JNK, and p38. These results suggest that Andrographolide exerts an anti-inflammatory effect by inhibiting the activation of NF-kappaB/MAPK signaling pathway and the induction of proinflammatory cytokines.
PDF
