MAP Kinase

JNK inhibitors: is there a future?

2016-06-23T11:08:05+00:00

JNK is a subfamily of MAP kinases that hat regulates a range of biological processes implicated in response to stress, such as cytokines, ultraviolet irradiation, heat shock, and osmotic shock as well as growth factors like PDGF, EGF, FGF, etc. They were originally identified as kinases that bind and phosphorylate JUN on S63 and Se73 within its transcriptional activation domain. The deregulation of these kinases is shown to be involved in human diseases, such as cancer, immune diseases and neurodegenerative disorders. The realization of the therapeutic potential of the inhibition of JNKs led to a thorough search for small-molecule inhibitors first for research purposes, but later also for therapeutic applications. Here, we discuss some of the most well-known JNK inhibitors and their use in basic research or clinical science.

Clinical candidates of small molecule p38 MAPK inhibitors for inflammatory diseases

2016-06-23T11:08:03+00:00

The trigger and etiology of chronic inflammatory diseases are not well understood, hindering the development of efficient therapeutic approaches. The observation that abnormal activity of the p38 MAPK is common to all inflammatory diseases raised the expectation that p38 inhibitors would serve as general anti-inflammatory therapeutics. A large number of inhibitors were consequently discovered. Several compounds of different scaffolds, blocking the p38 MAPK signaling pathway, have entered phase II clinical trials for rheumatoid arthritis, chronic obstructive pulmonary disease, pain, cardiovascular diseases, and cancer. As I review here, in almost all cases the clinical trials have failed, leading to re-design of compounds and re-evaluation of p38 as a suitable target. I describe how structural features, unique to p38α, have been employed in the inhibitor design and achieved high degree of kinome selectivity. I then focus on some of the drugs that reached human trials and summarize their in vitro/in vivo pharmacological profiles and the related outcomes from clinical investigations. These compounds include VX-745, VX-702, RO-4402257, SCIO- 469, BIRB-796, SD-0006, PH-797804, AMG-548, LY2228820, SB-681323 and GW-856553. Finally, I discuss novel suggested approaches for the use of p38 inhibitors such as combining p38 inhibition with inhibiting other targets that function in parallel inflammatory pathways for achieving efficacy in treating inflammatory diseases.

Modulation of host-cell MAPkinase signaling during fungal infection

2016-06-23T11:08:02+00:00

Fungal infections contribute substantially to human suffering and mortality. The interaction between fungal pathogens and their host involves the invasion and penetration of the surface epithelium, activation of cells of the innate immune system and the generation of an effective response to block infection. Numerous host-cell signaling pathways are activated during fungal infection. This review will focus on the main fungal pathogens Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans and their ability to activate the host MAP-kinase signaling pathways leading to cytokine secretion, increased cell motility and killing of the pathogen. Both epithelial and innate immune cells specifically recognize fungal antigens and in particular cell surface polysaccharides such as β-glucans and react to them by activating multiple signaling pathways, including those containing MAP-kinase modules. Recent findings suggest that the host response to fungal infection utilizes the MAP-kinase pathway to differentiate between commensal and pathogenic fungi to selectively react only to the pathogenic forms. However, the paucity of relevant publications strongly emphasize that our understanding of host MAP-kinase signaling in response to fungal infection is still at a very early stage. It is clear, based on studies of host MAP-kinase signaling during viral and bacterial infections, that in fungi as well, a wealth of exciting findings await us.