Carbamate JNK3 Inhibitors Show Promise as Effective Treatments for Alzheimer's Disease: In Vivo Studies on Mouse Models.

We have been developing new inhibitors for c-Jun N-terminal kinase 3 (JNK3) as a potential treatment for Alzheimer's disease (AD). We identified potential JNK3 inhibitors through pharmacodynamic optimization studies, including benzimidazole compounds 2 and 3, but their unreliable pharmacokinetic properties led us to develop carbamate inhibitors 2h and 3h. In vitro studies validated carbamate inhibitors 2h and 3h as potent and highly selective JNK3 inhibitors with favorable pharmacokinetic profiles. Oral administration of 2h and 3h to both APP/PS1 and 3xTg AD mouse models improved cognitive function, indicating their potential as effective treatments for Alzheimer's disease. Carbamate JNK3 inhibitor 3h, in particular, restored cognitive function to near-normal levels in the 3xTg mice model of AD and led to pTau reduction in the hippocampal tissues of 3xTg-AD mice during in vivo behavioral evaluations. We intend to further develop these carbamate JNK3 inhibitors in preclinical studies as a potential first-in-class treatment for AD.

Discovery of novel imidazole chemotypes as isoform-selective JNK3 inhibitors for the treatment of Alzheimer's disease.

Despite innumerable efforts to develop effective therapeutics, it is difficult to achieve breakthrough treatments for Alzheimer's disease (AD), and the main reason is probably the absence of a clear target. Here, we reveal c-Jun N-terminal kinase 3 (JNK3), a protein kinase explicitly expressed in the brain and involved in neuronal apoptosis, with a view toward providing effective treatment for AD. For many years, we have worked on JNK3 inhibitors and have discovered 2-aryl-1-pyrimidinyl-1H-imidazole-5-yl acetonitrile-based JNK3 inhibitors with superb potency (IC50 < 1.0 nM) and excellent selectivity over other protein kinases including isoforms JNK1 (>300 fold) and JNK2 (∼10 fold). Based on in vitro biological activity and DMPK properties, the lead compounds were selected for further in vivo studies. We confirmed that repeat administration of JNK3 inhibitors improved cognitive memory in APP/PS1 and the 3xTg mouse model. Overall, our results show that JNK3 could be a potential target protein for AD.

Pellino1 promotes chronic inflammatory skin disease via keratinocyte hyperproliferation and induction of the T helper 17 response.

Psoriasis is one of the most common immune-mediated chronic inflammatory skin diseases. However, little is known about the molecular mechanism underlying the immunological circuits that maintain innate and adaptive immune responses in established psoriasis. In this study, we found that the Pellino1 (Peli1) ubiquitin E3 ligase is activated by innate pattern-recognition receptors (PRRs), such as Toll-like receptors (TLRs), and is highly upregulated in human psoriatic skin lesions and murine psoriasis-like models. Increased Peli1 expression is strongly correlated with the immunopathogenesis of psoriasis by activating hyperproliferation of keratinocytes in the S and G2/M phases of the cell cycle and promoting chronic skin inflammation. Furthermore, Peli1-induced psoriasis-like lesions showed significant changes in the expression levels of several T helper 17 (Th17)-related cytokines, such as IL-17a, IL-21, IL-22, IL-23, and IL-24, indicating that overexpression of Peli1 resulted in the sequential engagement of the Th17 cell response. However, the overexpression of Peli1 in T cells was insufficient to trigger psoriasis, while T cells were indispensable for disease manifestation. In summary, our findings demonstrate that Peli1 is a critical cell cycle activator of innate immunity, which subsequently links Th17 cell immune responses to the psoriatic microenvironment.