A Crucial Role of Activin A-Mediated Growth Hormone Suppression in Mouse and Human Heart Failure

Infusion of bone marrow-derived mononuclear cells (BMMNC) has been reported to ameliorate cardiac dysfunction after acute myocardial infarction. In this study, we investigated whether infusion of BMMNC is also effective for non-ischemic heart failure model mice and the underlying mechanisms. Intravenous infusion of BMMNC showed transient cardioprotective effects on animal models with dilated cardiomyopathy (DCM) without their engraftment in heart, suggesting that BMMNC infusion improves cardiac function via humoral factors rather than their differentiation into cardiomyocytes. Using conditioned media from sorted BMMNC, we found that the cardioprotective effects were mediated by growth hormone (GH) secreted from myeloid (Gr-1(+)) cells and the effects was partially mediated by signal transducer and activator of transcription 3 in cardiomyocytes. On the other hand, the GH expression in Gr-1(+) cells was significantly downregulated in DCM mice compared with that in healthy control, suggesting that the environmental cue in heart failure might suppress the Gr-1(+) cells function. Activin A was upregulated in the serum of DCM models and induced downregulation of GH levels in Gr-1(+) cells and serum. Furthermore, humoral factors upregulated in heart failure including angiotensin II upregulated activin A in peripheral blood mononuclear cells (PBMNC) via activation of NFκB. Similarly, serum activin A levels were also significantly higher in DCM patients with heart failure than in healthy subjects and the GH levels in conditioned medium from PBMNC of DCM patients were lower than that in healthy subjects. Inhibition of activin A increased serum GH levels and improved cardiac function of DCM model mice. These results suggest that activin A causes heart failure by suppressing GH activity and that inhibition of activin A might become a novel strategy for the treatment of heart failure

The first total synthesis of apigenin 7-O--D-cellobiosyl-4-O--D-glucopyranoside isolated from Salvia uliginosa

The first total synthesis of apigenin 7-O--D-cellobioside (5) and apigenin 7-O--D-cellobiosyl-4-O--D-glucopyranoside (8), which were isolated from petals of Salvia patens and Salvia uliginosa, were achieved in four and six steps and 76% and 57%, respectively, overall yield, from naringenin (1). The total synthesis contained two-glycosylation, acetylation, oxidation, selective deacetylation and deprotection steps. Although this route contained six steps, the targeted compounds were obtained with higher yields and easier purifications than other synthetic methods

Emergence of Embryo Shape During Cleavage Divisions

International audienceCells are arranged into species-specific patterns during early embryogenesis. Such cell division patterns are important since they often reflect the distribution of localized cortical factors from eggs/fertilized eggs to specific cells as well as the emergence of organismal form. However, it has proven difficult to reveal the mechanisms that underlie the emergence of cell positioning patterns that underlie embryonic shape, likely because a system-level approach is required that integrates cell biological, genetic, developmental and mechanical parameters. The choice of organism to address such questions is also important. Because ascidians display the most extreme form of invariant cleavage pattern amongst the metazoans, we have been analyzing the cell biological mechanisms that underpin three aspects of cell division (unequal cell division (UCD), oriented cell division (OCD), and asynchronous cell cycles) which affect the overall shape of the blastula-stage ascidian embryo composed of 64 cells. In ascidians, UCD creates two small cells at the 16-cell stage that in turn undergo two further successive rounds of UCD. Starting at the 16-cell stage, the cell cycle becomes asynchronous whereby the vegetal half divides before the animal half, thus creating 24, 32, 44 then 64-cell stages. Perturbing either UCD or the alternate cell division rhythm perturbs cell position. By analyzing cell shape, we discovered that cell shape propagates, via cell-cell contact, throughout the embryo following UCD and alternate/asynchronous cell division to create the ascidian-specific invariant cleavage pattern via OCD in the longest length of the apical surface of blastomeres

Control of microtubule organization and dynamics : two ends in the limelight

Microtubules have fundamental roles in many essential biological processes, including cell division and intracellular transport. They assemble and disassemble from their two ends, denoted the plus end and the minus end. Significant advances have been made in our understanding of microtubule plus-end-tracking proteins (+TIPs) such as end-binding protein 1 (EB1), XMAP215, selected kinesins and dynein. By contrast, information on microtubule minus-end-targeting proteins (-TIPs), such as the calmodulin-regulated spectrin-associated proteins (CAMSAPs) and Patronin, has only recently started to emerge. Here, we review our current knowledge of factors, including microtubule-targeting agents, that associate with microtubule ends to control the dynamics and function of microtubules during the cell cycle and development