Psychopharmacological Effects of JNK Inhibitor in Posthypoxic Encephalopathy and Mechanisms of Their Development

Role of JNK in the Regulation of Xenobiotic Metabolizing Function of Hepatocytes

We studied the role of JNK in the regulation of the metabolism of xenobiotic venlafaxine by liver cells under in vitro conditions. The inhibitory role of this protein kinase in the biotransformation of this psychotropic agent by hepatocytes was demonstrated. JNK inhibitor added to the liver homogenate containing antidepressant enhanced and accelerated the formation of the only pharmacologically active venlafaxine metabolite O-desmethylvenlafaxine in the cell suspension. The results show the promise of studying modifiers of activity of intracellular signaling molecules (in particular, mitogen-activated protein kinases) to develop a fundamentally new approach to control the transformation of xenobiotics and to create a new class of pharmaceutical, target regulators of drugs metabolism.

Role of JNK and p53 in Implementation of Functions of Various Types of Regeneration-Competent Cells of the Nervous Tissue

We studied the participation of JNK and p53 in the realization of the growth potential of different types of progenitors of the subventricular zone of mouse brain and secretion of neurotrophins by glial cells. The stimulating role of these signaling molecules in mitotic activity and specialization of multipotent neural stem cells was shown. It was found that JNK and p53 do not participate in the regulation of committed neuronal progenitor cells (clonogenic PSA-NCAM⁺ cells). A dependence of neurotrophic growth factors in individual populations of neuroglia on activity of these protein kinase and transcription factor was revealed. The role of JNK and p53 in astrocytes consists in stimulation of their secretion, and in microglial cells, on the contrary, in its inhibition. The secretory neurotrophic function of oligodendrogliocytes is not associated with JNK and p53 activity.

Hemostimulating Effects of c-Jun N-Terminal Kinase (JNK) Inhibitor during Cytostatic Myelosuppression and Mechanisms of Their Development

The hemostimulating effects of c-Jun N-terminal kinase (JNK) inhibitor were examined on the mouse model of myelosuppression provoked by 5-fluorouracil. Blockade of JNK during postcytostatic period accelerated recovery of granulomonocytopoiesis and erythropoiesis. It also increased the content of neutrophilic granulocytes and erythroid cells in the hematopoietic tissue and elevated the counts of neutrophils and reticulocytes in the peripheral blood. The development of these phenomena resulted from elevated content and up-regulated functional activity of bone marrow hematopoietic progenitors associated with the direct action of JNK inhibitor on these progenitors and enhanced secretion of hemopoietins by stromal elements of the hematopoiesis-inducing microenvironment.

Role of JAK/STAT3 Signaling in Functional Stimulation of Mesenchymal Progenitor Cells by Fibroblast Growth Factor

JAK/STAT signaling pathway was examined during functional stimulation of mesenchymal progenitor cells with fibroblast growth factor. The differences were observed in the realizations of the proliferation-differentiation potential of CFU-fibroblasts under blockade of JAKs or during selective inactivation of STAT3. The study revealed stimulating influences of JAKs and STAT3 on mitotic activity of progenitor cells and individual roles of these proteins in the control of their maturation. Blockade of JAKs diminished the level of fibroblast colony formation and the score of actively proliferating CFU-fibroblasts at the background increase of the differentiation rate of progenitor cells. In contrast, STAT3 inhibitor resulted in a coordinated decrease of all examined parameters.

Role of JAK1, JAK2, and JAK3 in Functional Stimulation of Mesenchymal Precursor Cells by Alkaloid Songorine

We studied the role of some JAK in the effect of diterpene alkaloid songorine on realization of the growth potential of mesenchymal precursor cells. The participation of JAK1, JAK2, and JAK3 in stimulation of proliferation of the precursor cells was demonstrated. Specific inhibitors of these JAK reduced the yield of fibroblast CFU and the rate of their division. Inhibition of JAK2 against the background of songorine treatment increased the rate of precursor differentiation.