No abstract

We evaluated the possibility of hemopoiesis stimulation with hyaluronidase. The response of the blood system depended on the dose of this enzyme. Functional activity of hemopoietic precursor cells increased under the influence of hyaluronidase in a dose of 20 arb. units, which was accompanied by an increase in the secretion of hemopoietins by adherent myelokaryocytes and elevation of hemopoietic activity in blood plasma. The number of erythrokaryocytes and mature neutrophilic granulocytes in the bone marrow, as well as the count of reticulocytes and neutrophils in the peripheral blood increased under these conditions. Administration of hyaluronidase in a high dose (100 arb. units) led to uncoupling of proliferation and differentiation of hemopoietic precursors and produced no considerably changes in the blood.

We studied the mechanisms of regenerative (wound healing) effects of songorine associated with functional activation of mesenchymal progenitor cells. The key role of FGF receptors on these progenitor cells in the stimulation of realization of their growth potential under the effect of the alkaloid was demonstrated. Under in vitro conditions, the antibodies to FGF receptor abolished the songorine-induced increase in the number of fibroblast colony-forming units in bone marrow cell culture. The intensity of differentiation of mesenchymal precursors remained unchanged.

Signal pathways of realization of growth potential of mesenchymal progenitor cells related to transcription factor NF-κB were studied in vitro. NF-κB was found to participate in the proliferation and differentiation of progenitor elements that can be blocked by its specific inhibitor oridonin. NF-κB inhibitor aurothiomalate had no effect on the functions of fibroblastic CFU.

Specific JNK and p53 inhibitors stimulated the formation of fibroblast colonies (CFU-F) and clusters (ClFU-F) and increased proliferative activity of mesenchymal progenitor cells. No effects of inhibitors of JNK and p53 on differentiation of progenitor elements were revealed.

We studied the role of intracellular signal molecules PI3K, MAPK ERK1/2, and p38 in the realization of the growth potential of mesenchymal progenitor elements. Under in vitro conditions, PI3K и ERK1/2 specifi c inhibitors reduced fi broblastic colony- and cluster-formation and considerably suppressed proliferative activity of mesenchymal precursors. Blocker of p38 and protein kinase B had no effect on the function of fi broblast CFU.

We studied the role of signaling pathways in the regulation of erythropoiesis against the background of myelosuppression caused by administration of 5-fluorouracil. The important role of cyclic AMP in the maturation of erythroid progenitors after cytostatic treatment was demonstrated. The secretory activity of myelokaryocytes during the period of erythroid hemopoiesis recovery is mainly regulated via the p38 MAPK signaling pathway; non-erythropoietin factors are involved in the formation of erythropoietic activity of adherent cells of the microenvironment.

The effects of dimethylsulfoxide on the state of mesenchymal precursors in vivo were demonstrated. Treatment with dimethylsulfoxide reduced the content of stromal clonogenic elements in the bone marrow and inhibited mobilization of mesenchymal precursors induced by granulocyte colony-stimulating factor. In in vitro system, dimethylsulfoxide inhibited proliferation of fibroblast, erythroid, and granulomonocytic colony-forming units and stimulates maturation of hemopoietic precursors.