Autophagy is a regulator of TGF-β1-induced fibrogenesis in primary human atrial myofibroblasts

SLAMF1 regulation of chemotaxis and autophagy determines CLL patient response

Chronic lymphocytic leukemia (CLL) is a variable disease; therefore, markers to identify aggressive forms are essential for patient management. Here, we have shown that expression of the costimulatory molecule and microbial sensor SLAMF1 (also known as CD150) is lost in a subset of patients with an aggressive CLL that associates with a shorter time to first treatment and reduced overall survival. SLAMF1 silencing in CLL-like Mec-1 cells, which constitutively express SLAMF1, modulated pathways related to cell migration, cytoskeletal organization, and intracellular vesicle formation and recirculation. SLAMF1 deficiency associated with increased expression of CXCR4, CD38, and CD44, thereby positively affecting chemotactic responses to CXCL12. SLAMF1 ligation with an agonistic monoclonal antibody increased ROS accumulation and induced phosphorylation of p38, JNK1/2, and BCL2, thereby promoting the autophagic flux. Beclin1 dissociated from BCL2 in response to SLAMF1 ligation, resulting in formation of the autophagy macrocomplex, which contains SLAMF1, beclin1, and the enzyme VPS34. Accordingly, SLAMF1-silenced cells or SLAMF1(lo) primary CLL cells were resistant to autophagy-activating therapeutic agents, such as fludarabine and the BCL2 homology domain 3 mimetic ABT-737. Together, these results indicate that loss of SLAMF1 expression in CLL modulates genetic pathways that regulate chemotaxis and autophagy and that potentially affect drug responses, and suggest that these effects underlie unfavorable clinical outcome experienced by SLAMF1(lo) patients.

Autophagy activation attenuates angiotensin II-induced cardiac fibrosis

Autophagy has been involved in numerous diseases processes. However, little is known about the role of autophagy in cardiac fibrosis. Thus, whether or not angiotensin II (Ang II)-induced autophagy has a regulatory function on cardiac fibrosis was detected in vitro and in vivo. In rat cardiac fibroblasts (CFs) stimulated with Ang II, activated autophagy was observed using transmission electron microscopic analysis (TEM), immunofluorescence and Western blot. In Ang II-infused mice, increased co-localization of LC3 puncta with vimentin was observed. In rat CFs, co-treated with rapamycin (Rapa), an autophagy inducer, Ang II-induced the upregulation of type I collagen (Col-I), fibronectin (FN) was decreased. Conversely, inhibition of autophagy by chloroquine (CQ), an autophagy inhibitor, or knockdown of ATG5, a key component of the autophagy pathway by specific siRNA, aggravated Ang II-mediated the accumulation of Col-I and FN. Furthermore, in C57 BL/6 mice with Ang II infusion, intraperitoneal administration of Rapa ameliorated Ang II-induced cardiac fibrosis and cardiac dysfunction, while CQ treatment not only exacerbated Ang II-mediated cardiac fibrosis and cardiac dysfunction, but also impaired cardiac function. These findings suggest that autophagy may exert a protective role to attenuate excess extracellular matrix (ECM) accumulation in the heart.

Intermedin attenuates myocardial infarction through activation of autophagy in a rat model of ischemic heart failure via both cAMP and MAPK/ERK1/2 pathways

Intermedin is a proopiomelanocortin-derived peptide before opioid promoting cortical hormone, its main function embodies in mononuclear macrophages and neutrophilic granulocytes to inhibit the proinflammatory cytokines. The aim of this study is to determine intermedin attenuates myocardial infarction and its related mechanisms in a rat model of ischemic heart failure. After rat model of ischemic heart failure was set up, myocardial infarction, blood levels of activities of creatine kinase (CK), the MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase (LDH) and cardiac troponin T (cTnT) were effectively reduced by treatment with intermedin. Tumor necrosis factor (TNF-α) and interleukin-6 (IL-6) in a rat model of ischemic heart failure were recovered by pretreatment with intermedin. Administrate of intermedin availably promoted cAMP contents and suppressed caspase-3 protein in ischemic heart failure rat. ERK1/2 and LC3 protein expression were significantly activated and autophagy was significantly promoted by intermedin in a rat model of ischemic heart failure. These results indicate that intermedin protected rat heart, attenuates myocardial infarction from ischemic heart failure in the rat model. The underlying mechanisms may include upregulation of cAMP, ERK1/2 and LC3 protein expression and activating of autophagy.