Background: Macrophage-associated immune response plays an important role in myocardial ischemia/reperfusion (IR) injury. Dectin-1, expressed mainly on activated myeloid cells, is crucial for the regulation of immune homeostasis as a pattern recognition receptor. However, its effects and roles during the myocardial IR injury remain unknown. Methods: Genetic ablation, antibody blockade, or Dectin-1 activation, along with the adoptive bone marrow transfer chimeric model, was used to determine the functional significance of Dectin-1 in myocardial IR injury. Immune cell filtration and inflammation were examined by flow cytometry, quantitative real-time polymerase chain reaction, and immunohistochemistry. Moreover, Dectin-1 + cells were analyzed by flow cytometry in the blood of patients with ST-segment–elevation myocardial infarction and stable patients with normal coronary artery (control). Results: We demonstrated that Dectin-1 expression observed on the bone marrow–derived macrophages is increased in the heart during the early phase after IR injury. Dectin-1 deficiency and antibody-mediated Dectin-1 inhibition led to a considerable improvement in cardiac function, accompanied by a reduction in cardiomyocyte apoptosis, which was associated with a decrease in M1 macrophage polarization and Ly-6C + monocyte and neutrophil infiltration. Activation of Dectin-1 with its agonist had the opposite effects. Furthermore, Dectin-1 contributed to neutrophil recruitment through the regulation of Cxcl1 and granulocyte colony-stimulating factor expression. In addition, Dectin-1–dependent interleukin-23/interleukin-1β production was shown to be essential for interleukin-17A expression by γδT cells, leading to neutrophil recruitment and myocardial IR injury. Furthermore, we demonstrated that circulating Dectin-1 + CD14 ++ CD16 − and Dectin-1 + CD14 ++ CD16 + monocyte levels were significantly higher in patients with ST-segment–elevation myocardial infarction than in controls and positively correlated with the severity of cardiac dysfunction. Conclusions: Our results reveal a crucial role of Dectin-1 in the process of mouse myocardial IR injury and provide a new, clinically significant therapeutic target.

Rationale: Macrophages are critically involved in wound healing following myocardial infarction (MI). Lgr4, a member of leucine-rich repeat-containing G protein-coupled receptor (LGR) family, is emerging as a regulator of macrophage-associated immune responses. However, the contribution of Lgr4 to macrophage phenotype and function in the context of MI remains unclear. Objective: To determine the role of macrophage Lgr4 in MI and to dissect the underlying mechanisms. Methods and Results: During early inflammatory phase of MI, infarct macrophages rather than neutrophils expressed high level of Lgr4. Macrophage-specific Lgr4 knockout mice (Mac-L4KO) had no baseline cardiovascular defects but manifested improved heart function, modestly reduced infarct size, decreased early mortality due to cardiac rupture, and ameliorated adverse remodeling after MI. Improved outcomes in Mac-L4KO mice subjected to MI were associated with mitigated ischemic injury and optimal infarct healing, as determined by reduction of cardiac apoptosis in the peri-infarct zone, attenuation of local myocardial inflammatory response, decrease of matrix metalloproteinase expression in the infarct, enhancement of angiogenesis, myofibroblast proliferation, and collagen I deposition in reparative granulation tissue as well as formation of collagen-rich scar. More importantly, Mac-L4KO infarcts had reduced numbers of infiltrating leukocytes and inflammatory macrophages but harbored abundant reparative macrophage subsets. Lgr4-null infarct macrophages exhibited a less inflammatory transcriptional signature. These findings were further supported by transcriptomic profiling data showing repression of multiple pathways and broad-spectrum genes associated with pro-inflammatory responses in Mac-L4KO infarcts. Notably, we discovered that Lgr4-mediated functional phenotype programing in infarct macrophages was at least partly attributed to regulation of activator protein (AP)-1 activity. We further demonstrated that the synergistic effects of Lgr4 on AP-1 activation in inflammatory macrophages occurred via enhancing cAMP response element-binding protein (CREB)-mediated c-Fos, Fosl1, and Fosb transactivation. Conclusions: Together, our data highlight the significance of Lgr4 in governing pro-inflammatory phenotype of infarct macrophages and post-infarction repair.

Objective This study investigated the sources of stress, corresponding symptoms, and stress relief among nurses of the first Chinese anti-Ebola medical team during the Sierra Leone aid mission. Method A purposive sampling method was used and 10 nurses were selected from the first Chinese anti-Ebola medical team that was dispatched to Sierra Leone. Data were collected via phone and semi-structured interviews, then analyzed using Colaizzi's seven-step method. Results The data showed three major themes: (1) The causes of stress during the Sierra Leone aid mission mainly related to unsafety, responsibility, and unfamiliarity; (2) Physical, cognitive, emotional, and behavioral symptoms were documented; (3) Nurses experienced relief from stress after the mission. Conclusion Targeted measures, proper responses and good community support can effectively lower stress among nurses on anti-Ebola missions.

Background: Heart failure is a global public health issue that is associated with increasing morbidity and mortality. Previous studies have suggested that mitochondrial dysfunction plays critical roles in the progression of heart failure; however, the underlying mechanisms remain unclear. Since kinases have been reported to modulate mitochondrial function, we investigated the effects of dual-specificity tyrosine-regulated kinase 1B (DYRK1B) on mitochondrial bioenergetics, cardiac hypertrophy, and heart failure. Methods: We engineered DYRK1B transgenic and knock out mice and used transverse aortic constriction (TAC) to produce an in vivo model of cardiac hypertrophy. The effects of DYRK1B and its downstream mediators were subsequently elucidated using RNA-seq analysis and mitochondrial functional analysis. Results: We found that DYRK1B expression was clearly upregulated in failing human myocardium as well as in hypertrophic murine hearts. Cardiac-specific DYRK1B overexpression resulted in cardiac dysfunction accompanied by a decline in the left ventricular ejection fraction, fraction shortening, and increased cardiac fibrosis. In striking contrast to DYRK1B overexpression, the deletion of DYRK1B mitigated TAC-induced cardiac hypertrophy and heart failure. Mechanistically, DYRK1B was positively associated with impaired mitochondrial bioenergetics by directly binding with STAT3 to increase its phosphorylation and nuclear accumulation, ultimately contributing toward the downregulation of PGC-1α. Furthermore, the inhibition of DYRK1B or STAT3 activity using specific inhibitors was able to restore cardiac performance by rejuvenating mitochondrial bioenergetics. Conclusions: Taken together, the findings of this study provide new insights into the previously unrecognized role of DYRK1B in mitochondrial bioenergetics and the progression of cardiac hypertrophy and heart failure. Consequently, these findings may provide new therapeutic options for patients with heart failure.