Insight into JNK Inhibition-based Strategy for the Treatment of Alzheimer's Disease

Existing drugs for the treatment of Alzheimer's disease do not meet the basic requirements. Therefore, it is necessary to search for fundamentally new targets for the discovery of drugs for Alzheimer's disease (AD). When creating approaches to stimulate neurogenesis, such a search is promising to conduct as part of the development of a strategy for targeted regulation of intracellular signal transduction in regeneration-competent cells (RCCs). Moreover, the participation of c-Jun N-terminal kinases (JNK) in the regulation of the functions of the nervous tissue and neuroglial cells is known. The aim of the work was to study the effect of the JNK inhibitor (IQ-1S) on exploratory behavior and cognitive functions in aged mice (16-month-old male C57BL/6 mice as a model of AD) in combination with the dynamics of shifts in the RCCs functioning (nervous tissue progenitors: neural stem cells (NSCs) and neuronal-committed progenitors (NCPs); neuroglial cells: astrocytes, oligodendrocytes, microglial cells). The studies were carried out on male C57BL/6 mice aged 16 months as model of Alzheimer's disease. We studied the effect of the JNK inhibitor on exploratory behavior, conditioned reflex activity, and on the functioning of RCCs in the subventricular zone of the cerebral hemispheres (SVZ). NCPs and neuroglial cells of different types were obtained by immunomagnetic separation. We observed significant changes in exploratory behavior and impaired conditioned reflex activity in aged C57BL/6 mice. The administration of the JNK inhibitor led to a significant correction of age-related behavioral and memory disorders in aged mice. At the same time, against the background of JNK inhibition-based therapy, an increase in mitotic activity and the content of both NSCs and NCPs in the SVZ was noted. However, these shifts were more pronounced in committed precursors. The phenomenon of the inhibition of NSC specialization under the influence of a pharmacological agent was also revealed. In addition, the JNK inhibitor caused an increase in the secretion of neurotrophic growth factors by oligodendrocytes and microglial cells. The findings open up prospects for the development of JNK targeting-based approaches for the treatment of AD.