Background: In normal hearts, capillaries are densely distributed throughout the myocardial tissue, and the cross-talk between myocytes and capillary endothelial cells plays a pivotal role in regulating cardiac development, maturation and function. Although previous studies have suggested a role for the endothelium in the organisation of nearby cardiomyocytes, the underlying mechanism has yet to be illustrated. Methods and Results: Using a transwell coculture system, we studied the paracrine effect of endothelial cells on cardiomyocytes and found that the regulation of cardiomyocyte spatial reorganisation and cytoskeletal dynamics by endothelial cells was coupled with β1-integrin induction. To determine the role of β1-integrin in this process, we preincubated myocytes with a β1-integrin function-blocking antibody before coculture. β1-integrin blockage abolished myocyte chemotactic activity and inhibited microtubule extension and stress fibre assembly. We further evaluated the therapeutic potential of combined endothelial cell-cardiac myocyte transplantation against ischemic cardiomyopathy in an acute myocardial infarction (AMI) mouse model. The results showed that myocytes and endothelial cells synergistically promoted ischemic myocardial repair, as evidenced by the robust engraftment and migration of implanted cells within the infarcted area, as well as the stimulation of angiogenesis, the attenuation of scar tissue and the improvement of cardiac function. Conclusion: Our study demonstrated the necessity of β1-integrin in the interactions between cardiomyocytes and endothelial cells and presented a novel combined transplantation approach that might hold promise for treating ischemic cardiomyopathy.

Interferon-γ (IFN-γ) is critical for innate and adaptive immunity against viral and bacterial infections. IFN-γ reportedly affects the phagocytic ability of monocytes and macrophages as well as regulates pituitary function in humans and mice. The present study analyzed the impact of IFN-γ on monocyte and macrophage phagocytosis, production performance, and pituitary function in vivo and in vitro (in dwarf chickens). IFN-γ was injected into dwarf chickens through a vein, and then, the laying rate, average egg weight, and levels of follicle-stimulating hormone (FSH) and IFN-γ were measured in treatment and control groups. For the in vitro experiment, the pituitary tissues were supplemented with IFN-γ, and the mRNA expression levels of follicle-stimulating hormone beta subunit (FSH-β), interferon gamma receptor 1 (IFNGR1), and interferon gamma receptor 2 (IFNGR2) in the pituitary were assessed. Monocyte and macrophage phagocytosis product (PP) was decreased by IFN-γ treatment in a dose-dependent manner in vitro. In the in vivo experiment, the level of IFN-γ in the treatment group was higher than that in the control group at 7 d (P < 0.05), 14 d (P < 0.01), and 21 d (P < 0.01) post-injection. Compared with the control group, monocyte and macrophage PP was lower in the treatment group after injection (P < 0.01). The laying rate was higher in the treatment group than in the control group at 2 and 3 wk post-injection (P < 0.05). There was a significant difference between the treatment and control groups in the levels of FSH at 1, 3, 7, and 14 d post-injection (P < 0.01). In the in vitro experiment, increased mRNA expression levels of FSH-β, IFNGR1, and IFNGR2 were observed in the treatment group after stimulation with 100 U/mL IFN-γ for 24 h compared to those in the control group (P < 0.05). IFN-γ inhibited the phagocytosis of monocytes and macrophages; up-regulated the mRNA expression levels of the FSH-β, IFNGR1, and IFNGR2; enhanced the secretion of FSH; and improved the laying rate. IFN-γ might be an important regulator in the trade-off between the immune effect and production performance in dwarf chickens.

Background: Avian infectious bronchitis virus (IBV) is a major cause of poor weight gain and mortality among chicks. Methods: A lentivirus vector was used to generate transgenic chickens expressing small interfering RNA (siRNA) targeting the M protein of IBV. Offspring of generation 0 (G0) were screened to identify G1 transgenic chickens (Tg). Monocytes from G1 Tg were stimulated with IBV in vitro. Results: Monocytes producing siRNA efficiently inhibit IBV replication. Expression of inflammatory cytokines, Mx protein and nitric oxide levels were lower in early IBV infection in Tg. In vivo experiments show that siRNA expression inhibits IBV replication, significantly decreases mortality and increases weight gain. Inflammatory responses and oxidative damage were significantly decreased, yielding minimal tissue injury. The inflammatory responses indicate that the cellular immune response is most effective during the initial stage, while the humoral immune response is more significant in later stages of infection. Conclusions: Small interfering RNA expression inhibits avian IBV replication and inflammatory response.