Macrophage CARD9 mediates cardiac injury following myocardial infarction through regulation of lipocalin 2 expression

Immune cell infiltration in response to myocyte death regulates extracellular matrix remodeling and scar formation after myocardial infarction (MI). Caspase-recruitment domain family member 9 (CARD9) acts as an adapter that mediates the transduction of pro-inflammatory signaling cascades in innate immunity; however, its role in cardiac injury and repair post-MI remains unclear. We found that Card9 was one of the most upregulated Card genes in the ischemic myocardium of mice. CARD9 expression increased considerably 1 day post-MI and declined by day 7 post-MI. Moreover, CARD9 was mainly expressed in F4/80-positive macrophages. Card9 knockout (KO) led to left ventricular function improvement and infarct scar size reduction in mice 28 days post-MI. Additionally, Card9 KO suppressed cardiomyocyte apoptosis in the border region and attenuated matrix metalloproteinase (MMP) expression. RNA sequencing revealed that Card9 KO significantly suppressed lipocalin 2 (Lcn2) expression post-MI. Both LCN2 and the receptor solute carrier family 22 member 17 (SL22A17) were detected in macrophages. Subsequently, we demonstrated that Card9 overexpression increased LCN2 expression, while Card9 KO inhibited necrotic cell-induced LCN2 upregulation in macrophages, likely through NF-κB. Lcn2 KO showed beneficial effects post-MI, and recombinant LCN2 diminished the protective effects of Card9 KO in vivo. Lcn2 KO reduced MMP9 post-MI, and Lcn2 overexpression increased Mmp9 expression in macrophages. Slc22a17 knockdown in macrophages reduced MMP9 release with recombinant LCN2 treatment. In conclusion, our results demonstrate that macrophage CARD9 mediates the deterioration of cardiac function and adverse remodeling post-MI via LCN2.

Abnormal adenosine metabolism of neutrophils inhibits airway inflammation and remodeling in asthma model induced by Aspergillus fumigatus

BACKGROUND

Neutrophils consume a large amount of energy when performing their functions. Compared with other white blood cells, neutrophils contain few mitochondria and mainly rely on glycolysis and gluconeogenesis to produce ATP. The inflammatory site is hypoxic and nutrient poor. Our aim is to study the role of abnormal adenosine metabolism of neutrophils in the asthmatic airway inflammation microenvironment.

METHOD

In this study, an asthma model was established by intratracheal instillation of Aspergillus fumigatus extract in Ecto-5'-Nucleotidase (CD73) gene-knockout and wild-type mice. Multiple analyses from bronchoalveolar lavage fluid (BALF) were used to determine the levels of cytokines and chemokines. Immunohistochemistry was used to detect subcutaneous fibrosis and inflammatory cell infiltration. Finally, adenosine 5'-(α, β-methylene) diphosphate (APCP), a CD73 inhibitor, was pumped subcutaneously before Aspergillus attack to observe the infiltration of inflammatory cells and subcutaneous fibrosis to clarify its therapeutic effect.

RESULT

PAS staining showed that CD73 knockout inhibited pulmonary epithelial cell proliferation and bronchial fibrosis induced by Aspergillus extract. The genetic knockdownof CD73 significantly reduced the production of Th2 cytokines, interleukin (IL)-4, IL-6, IL-13, chemokine (C-C motif) ligand 5 (CCL5), eosinophil chemokine, neutrophil IL-17, and granulocyte colony-stimulating factor (G-CSF). In addition, exogenous adenosine supplementation increased airway inflammation. Finally, the CD73 inhibitor APCP was administered to reduce inflammation and subcutaneous fibrosis.

CONCLUSION

Elevated adenosine metabolism plays an inflammatory role in asthma, and CD73 could be a potential therapeutic target for asthma.

AMP-activated protein kinase α2 protects against liver injury from metastasized tumors via reduced glucose deprivation-induced oxidative stress

It is well known that tumors damage affected tissues; however, the specific mechanism underlying such damage remains elusive. AMP-activated protein kinase (AMPK) senses energetic changes and regulates glucose metabolism. In this study, we examined the mechanisms by which AMPK promotes metabolic adaptation in the tumor-bearing liver using a murine model of colon cancer liver metastasis. Knock-out of AMPK α2 significantly enhanced tumor-induced glucose deprivation in the liver and increased the extent of liver injury and hepatocyte death. Mechanistically, we observed that AMPK α2 deficiency resulted in elevated reactive oxygen species, reduced mitophagy, and increased cell death in response to tumors or glucose deprivation in vitro. These results imply that AMPK α2 is essential for attenuation of liver injury during tumor metastasis via hepatic glucose deprivation and mitophagy-mediated inhibition of reactive oxygen species production. Therefore, AMPK α2 might represent an important therapeutic target for colon cancer metastasis-induced liver injury.

[Effect of Sorbaria Sorbifolia extract on anti-oxidative activities in rats with precancerosis induced by diethylnitrosamine]

OBJECTIVE

To study the effect of Sorbaria Sorbifolia extract on anti-oxidative activities in rats with precancerosis induced by diethylnitrosamine.

METHODS

Sorbaria sorbifolia was perfused into stomach of rats with DEN-induced precancerosis, then the biochemical indexes were investigated. The activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and the concentrations of malondialdehyde (MDA), glutathione (GSH) were investigated by colorimetric method.

RESULTS

Sorbaria sorbifolia extract increased SOD, GSH-PX and decreased MDA, GSH levels in serum and liver homogenate.

CONCLUSION

Sorbaria Sorbifolia extract significantly increased anti-oxidative activities in rats with precancerosis induced by diethylnitrosamine.