[The functional characteristics oF TRPV5 and TRPV6 channels in normal and transformed human blood lymphocytes].

Calcium signaling and Ca(2+)-conducting channels are involved in the development of immune response, cell proliferation, growth and differentiation of lymphocytes. In this paper the calcium channels TRPV5 and TRPV6 (transient receptor potential vanilloid channels) were studied in the plasma membrane of T cell line Jurkat and normal human blood lymphocytes. The channels were activated by removing Ca2+ and Mg2+ from surrounding solution, characterized by inward rectification, and were inactivated by the effective blocker of TRPV5 and TRPV6, ruthenium red. Channel activity was significantly higher in Jurkat cells, than in normal human lymphocytes. Quantitative PCR analysis revealed higher levels of mRNA genes encoding channels TRPV5 and TRPV6 in the proliferation cells compared with resting lymphocytes. In general these data showed that TRPV5/TRPV6 in human lymphocytes are functionally active, and their activity is associated with proliferative status of blood cells.

[Long-term regulation of Na+, K+-ATPase pump in human lymphocytes: the role of JAK/STAT- and MAPK-signaling pathways].

In interleukin-2 (IL-2)-induced human blood lymphocytes, the Na+/K+ pump function (assessed by ouabain-sensitive Rb+ influx), the abundance of Na+, K+-ATPase alpha1-subunit (determined by Western blotting) and the alpha1- and beta1-subunits mRNA of Na+, K+-ATPase (RT-PCR), as well as the phosphorylation of STAT5 and STAT3 family proteins and ERK1/2 kinase have been examined. A 3.5-4.0-fold increase in the expression of alpha1- and beta1-subunits mRNA of Na+, K+-ATPase was found at 24 h of IL-2 stimulation. The inhibitors of JAK3 kinase (B-42, WHI-P431) was shown to decrease both the phosphorylation of STATs and the rise in the oubain-sensitive rubidium influx as well as the increased abundance of Na+, K+-ATPase alpha1-subunit. The inhibition of the protein kinases ERK1/2 by PD98059 (20 microM) suppressed the alpha1-subunit accumulation. All the kinase inhibitors tested did not alter the intracellular content ofmonovalent cations in resting and IL-2-stimulated lymphocytes. It is concluded that MAPK and JAK/STAT signaling pathways mediate the IL-2-dependent regulation of the Na+, K+-ATPase expression during the lymphocyte transition from resting stage to proliferation.

[TRPV5 and TRPV6 calcium channels in human T cells].

The recent cloning of the special calcium channels TRPV5 and TRPV6 (transient receptor potential vanilloid channels) provided the molecular base for the studying of new candidate of calcium influx in non-excitable cells. Using RT-PCR technique we obtained endogenous expression of the mRNAs trpv5 and trpv6 in lymphoblast leukemia Jurkat cells and in human blood primary T lymphocytes. Additionally, Western blot analysis showed TRPV5 proteins in both the whole lysate and in the crude membrane preparations from Jurkat cells and normal T lymphocytes. The using of the immunoprecipitation revealed TRPV6 proteins in Jurkat cells, whereas in normal T lymphocytes TRPV6 was not detected. The expression pattern and the selective Ca2+ permeation properties of TRPV5 and TRPV6 channels indicate an important role of these channels in the Ca2+ homeostasis and probably in malignant transformation of blood cells.

[Study of "group" expression of mRNA of the ion transporters ATP1B1, NHE1 and NKCC1, beta-actin, glycerophosphosphate dehydrogenase, proteins regulating proliferation and apoptosis of p53, Bcl-2, IL-2 and hSGK kinase at the prereplicative stage of human lymphocyte activation]. / Issledovanie "gruppovoi" ékspressii mRNK ionnykh transporterov ATP1B1, NHE1 i NKCC1, beta-aktina, glitserofosfatdegidrogenazy, belkov--reguliatorov proliferatsii i apoptoza p53, Bcl-2, IL-2 i kinazy hSGK na predreplikativnoi stadii aktivatsii limfotsitov cheloveka.

Previously, we found no segregation in F2 obtained from crosses between two Dileptus anser clones differing (under the same culture conditions) in their serotypes, i.e. in their immobilization antigens (i-antigens); indeed, all the F2 clones had mixed, i.e. hybrid serotype, being immobilized simultaneously with both immune sera developed against either parental clone (Uspenskaya, Yudin, 2000). Presently, experiments were carried out to see if this unusual phenotype would be re-expressed after a temporary switching off. To switch off both expressed i-antigens, serotype transformation was induced in the F2 clones by shifting the culture temperature from 25 to 17 degrees C. Two weeks later, when the clones returned to the initial temperature conditions, each of them was seen to re-express both parental i-antigens. This result is discussed with reference to the role of i-antigens in regulation of their own expression as has been suggested by some authors.