Gene transfection of hepatocyte growth factor attenuates the progression of cardiac remodeling in the hypertrophied heart

Cardiac concentric hypertrophy promoted by activated Met receptor is mitigated in vivo by inhibition of Erk1,2 signalling with Pimasertib

Cardiac hypertrophy is a major risk factor for heart failure. Hence, its attenuation represents an important clinical goal. Erk1,2 signalling is pivotal in the cardiac response to stress, suggesting that its inhibition may be a good strategy to revert heart hypertrophy. In this work, we unveiled the events associated with cardiac hypertrophy by means of a transgenic model expressing activated Met receptor. c-Met proto-oncogene encodes for the tyrosine kinase receptor of Hepatocyte growth factor and is a strong inducer of Ras-Raf-Mek-Erk1,2 pathway. We showed that three weeks after the induction of activated Met, the heart presents a remarkable concentric hypertrophy, with no signs of congestive failure and preserved contractility. Cardiac enlargement is accompanied by upregulation of growth-regulating transcription factors, natriuretic peptides, cytoskeletal proteins, and Extracellular Matrix remodelling factors (Timp1 and Pai1). At a later stage, cardiac hypertrophic remodelling results into heart failure with preserved systolic function. Prevention trial by suppressing activated Met showed that cardiac hypertrophy is reversible, and progression to heart failure is prevented. Notably, treatment with Pimasertib, Mek1 inhibitor, attenuates cardiac hypertrophy and remodelling. Our results suggest that modulation of Erk1.2 signalling may constitute a new therapeutic approach for treating cardiac hypertrophies.

Hepatocyte growth factor and basic fibroblast growth factor regulate atrial fibrosis in patients with atrial fibrillation and rheumatic heart disease via the mitogen-activated protein kinase signaling pathway

The aim of this study was to investigate the interrelation between basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF) and atrial fibrosis in patients with atrial fibrillation (AF) and rheumatic heart disease (RHD), and to explore the possible molecular mechanisms underlying this interrelation. Twenty patients with RHD who were scheduled for valve replacement were divided into two groups, comprising 10 cases with AF and 10 cases with sinus rhythm (SR). Clinical data were collected and a small sample of aseptic left atrial appendage was collected by the surgeon. Hematoxylin and eosin (H&E) and Masson's trichrome-stained sections were used to evaluate the cross-sectional area and level of fibrosis, respectively. The expression levels of bFGF and HGF were assessed using immunohistochemistry. The phosphorylation levels of mitogen-activated protein kinase/extracellular signal-regulated kinase 1/2 (MEK1/2), c-Jun N-terminal kinase 1/2 (JNK1/2), extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 in atrial tissue were measured using western blotting. Compared with the SR group, myocardial cell diameter was significantly expanded and there was increased collagen deposition in the AF group (P<0.05). The distribution of bFGF in the AF group was significantly higher than that in the SR group (P<0.05); however, HGF levels were significantly lower in the AF group (P<0.05). The phosphorylation levels of MEK1/2, ERK1/2, JNK1/2 and p38 in the AF group were significantly higher than those in the SR group (P<0.05). The results indicated that bFGF may promote the development of atrial fibrosis, while HGF may function in an opposite manner in patients with AF and RHD. The mitogen-activated protein kinase (MAPK) signaling pathway may be the molecular basis for these roles in atrial fibrosis.

Building Cell Selectivity into CPP-Mediated Strategies

There is a pressing need for more effective and selective therapies for cancer and other diseases. Consequently, much effort is being devoted to the development of alternative experimental approaches based on selective systems, which are designed to be specifically directed against target cells. In addition, a large number of highly potent therapeutic molecules are being discovered. However, they do not reach clinical trials because of their low delivery, poor specificity or their incapacity to bypass the plasma membrane. Cell-penetrating peptides (CPPs) are an open door for cell-impermeable compounds to reach intracellular targets. Putting all these together, research is sailing in the direction of the design of systems with the capacity to transport new drugs into a target cell. Some CPPs show cell type specificity while others require modifications or form part of more sophisticated drug delivery systems. In this review article we summarize several strategies for directed drug delivery involving CPPs that have been reported in the literature.