Novel ASK1 inhibitor AGI-1067 improves AGE-induced cardiac dysfunction by inhibiting MKKs/p38 MAPK and NF-κB apoptotic signaling

Recent Advances in c-Jun N-Terminal Kinase (JNK) Inhibitors

c-Jun N-Terminal Kinases (JNKs), members of the Mitogen-Activated Protein Kinase (MAPK) signaling pathway, play a key role in the pathogenesis of many diseases including cancer, inflammation, Parkinson's disease, Alzheimer's disease, cardiovascular disease, obesity, and diabetes. Therefore, JNKs represent new and excellent target by therapeutic agents. Many JNK inhibitors based on different molecular scaffolds have been discovered in the past decade. However, only a few of them have advanced to clinical trials. The major obstacle for the development of JNK inhibitors as therapeutic agents is the JNKisoform selectivity. In this review, we describe the recent development of JNK inhibitors, including ATP competitive and ATP non-competitive (allosteric) inhibitors, bidentatebinding inhibitors and dual inhibitors, the challenges, and the future direction of JNK inhibitors as potential therapeutic agents.

Higenamine Improves Cardiac and Renal Fibrosis in Rats With Cardiorenal Syndrome via ASK1 Signaling Pathway

The pathogenesis of cardiorenal syndrome (CRS) is very complex, and currently there is no effective treatment for CRS. Higenamine (HI) has been shown to improve cardiac function in rats with heart failure. However, the role of higenamine in CRS remains unknown. Here, in vitro, higenamine treatment markedly reduced neonatal rat cardiac fibroblast collagen synthesis and inhibited neonatal rat cardiac myocyte hypertrophy. In our study, a rat model of type 2 CRS was induced by left anterior descending coronary artery ligation combined with 5/6 subtotal nephrectomy (STNx). Higenamine treatment decreased serum creatinine (Scr), blood urea nitrogen, and brain natriuretic peptide levels and was capable of improving left ventricular remodeling and systolic function in CRS rats, accompanied with decreased expression of transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA) and collagen I (Col1A1). Moreover, higenamine significantly inhibited the protein expression of phosphorylated apoptosis signal-regulated kinase 1 (p-ASK1) and downstream mitogen-activated protein kinases (MAPK) (ERK, P38)/NF-κB in cardiorenal tissues of CRS rats and neonatal rat cardiac fibroblast/neonatal rat cardiac myocyte cells. Our study demonstrated that higenamine improved cardiorenal function in CRS rats and attenuated heart and kidney fibrosis possibly via targeting ASK1/MAPK (ERK, P38)/NF-κB signaling pathway. This finding extends our knowledge on the role of higenamine in cardiorenal fibrosis, providing a potential target to prevent the progression of CRS.

Heart Failure in Diabetes Mellitus: An Updated Review

Diabetes mellitus (DM) and heart failure (HF) are comorbid conditions associated with significant morbidity and mortality worldwide. Despite the availability of novel and effective therapeutic options and intensive glycaemic control strategies, mortality and hospitalisation rates continue to remain high and the incidence of HF persists. In this review, we described the impact of currently available glucose-lowering therapies in DM with a focus on HF clinical outcomes. Non-conventional modes of management and alternative pathophysiological mechanisms with the potential for therapeutic targeting are also discussed.

Baicalin Suppresses Bilirubin-Induced Apoptosis and Inflammation by Regulating p38 Mitogen-Activated Protein Kinases (MAPK) Signaling in Neonatal Neurons

Background

Hyperbilirubinemia is associated with central nervous system damage in preterm neonates due to the neurotoxicity of bilirubin. This study explored the possible mechanisms of bilirubin’s neurotoxicity, and the protective effect of baicalin (BAI) was also investigated.

Material/Methods

Isolated neonatal rat hippocampal neurons were exposed to free bilirubin (Bf). BAI was used to treat these neurons. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate the cell viability. Terminal deoxynucleotidyl transferase-dUTP nick-end labeling (TUNEL) assay was used to detect apoptosis. Contents of inflammatory cytokines were determined by enzyme-linked immunosorbent assay (ELISA). Protein expression and phosphorylation levels were assessed by Western blotting. Nuclear translocation was observed by immunofluorescent staining.

Results

Bf incubation significantly induced apoptosis and decreased viabilities of neurons. The phosphorylation levels of MAP kinase kinase (MKK)3, MKK6, p38 mitogen-activated protein kinases (MAPK), nuclear translocation level of p65, and the expression levels of cleaved caspase3 and tumor necrosis factor (TNF)α were found to be dramatically higher in Bf-incubated neurons. BAI pre-treatment, however, increased cell viability by reducing cell apoptosis. BAI pre-treatment also reduced phosphorylation levels of MKK3, MKK6, p38 MAPK, and nuclear translocation level of p65, as well as the expression levels of cleaved caspase3 and TNFα, in Bf-incubated neurons.

Conclusions

BAI suppressed bilirubin-induced neuron apoptosis and inflammation by deactivating p38 MAPK signaling.