Role of Thy-1,2<Superscript>+</Superscript> cells in the regulation of hemopoiesis during severe hypoxia

We studied the state of the bone marrow Thy-1,2⁺ cell pool under conditions of severe hypoxia. T cell mechanisms of hemopoiesis regulation are preserved under conditions of severe oxygen deficiency due to changes in functional properties of Thy-1,2⁺ cells. We revealed an indirect (mediated through cooperation with adherent myelokaryocytes) stimulating effect of Thy-1,2⁺ cells on erythroid precursors as well as direct and indirect feeder effects of these cells on granulocyte-monocyte precursors. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 1, pp. 23–27, January, 2007     

Dissociation between force and maximal Na<Superscript>+</Superscript>, K<Superscript>+</Superscript>-ATPase activity in rat fast-twitch skeletal muscle with fatiguing in vitro stimulation

This study investigated whether high frequency in vitro stimulation of rat fast-twitch extensor digitorum longus muscle depresses Na⁺, K⁺-ATPase (NKA) activity as measured by the maximal in vitro 3-O-MFPase assay. EDL muscles subjected to 10 s continuous 100 Hz stimulation reduced tetanic force by 51.8 ± 5.1% which recovered to 81.2 ± 6.1% after 1 min and remained stable over 1 h recovery period. A second bout reduced force by 50.3 ± 3.8% of initial but had no effect on 3-O-MFPase activity. Three minutes of intermittent stimulation (1 s at 100 Hz and 4 s recovery) resulted in 87.0 ± 2.8% decline force with slow recovery (62.7 ± 5.8% of initial after 1 h). The second 3-min bout reduced force by 83.3 ± 3.6% of initial with no change in maximal 3-O-MFPase activity. These findings contrast previous human studies where fatiguing voluntary exercise depresses maximal NKA activity. This suggests that NKA in rat fast-twitch muscle is resistant to fatigue-induced inactivation under these conditions. Furthermore, the loss of force with fatigue was not related to depressed maximal NKA activity.     

Effect of adaptation to stress and periodic hypoxia on cardiomyocyte resting and acting potentials in the isolated heart during ischemia and reperfusion

Research Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. N. A. Testemitsianu Kishinev Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR N. R Paleev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 12, pp. 573–575, December, 1991.     

Increased α1-adrenoceptor activity of the rat heart during adaptation to intermittent hypoxia

Research Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. Research Institute of Experimental Cardiology, All-Union Cardiologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. D. Ado.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 111, No. 6, pp. 570–572, June, 1991.     

CD<Subscript>4</Subscript><Superscript>+</Superscript>CD<Subscript>25</Subscript><Superscript>+</Superscript> Regulatory T Cells Decreased the Antitumor Activity of Cytokine-Induced Killer (CIK) Cells of Lung Cancer Patients

CD₄ ⁺CD₂₅ ⁺ regulatory T cells (Tregs) have been shown to inhibit cytotoxic lymphocytes-mediated immune responses. Cytokine-induced killer (CIK) cells exert high impact on adoptive immunotherapeutic approaches. Therefore, the purpose of this report was to determine the effect of Tregs on CIK cell growth and CIK-induced cytotoxicity for inhibition of tumor growth in vivo as well as in vitro. After depletion of CD₄ ⁺CD₂₅ ⁺ cells before culture, the proliferation and cytotoxicity of CIK cells, which indicated in bromodeoxyuridine (BrdU) and lactic dehydrogenase (LDH) assays, were significantly increased. Depletion of CD₄ ⁺CD₂₅ ⁺ cells preculture also enhanced the suppression effect on the lung cancer cells inoculated in experimental animals. Blockage of glucocorticoid-induced tumor necrosis factor receptor (GITR) and transforming growth factor β1 (TGF-β1) by antibodies partially abrogated the suppressive effect of CD₄ ⁺CD₂₅ ⁺ cells on CIK. These results indicated that Tregs could inhibit the antitumor activity of CIK cells. The molecules TGF-β and GITR may contribute to the suppressive function of CD₄ ⁺CD₂₅ ⁺ cells.     

The inhibitory effects of H<Superscript>+</Superscript>K<Superscript>+</Superscript>ATPase inhibitors on human neutrophils <Emphasis Type="Italic">in vitro</Emphasis>: Restoration by a K<Superscript>+</Superscript> ionophore

Objective: This study investigated the ability of proton pump inhibitors (PPI), such as omeprazole and pantoprazole, to inhibit neutrophil migration, calcium mobilization and the mechanisms involved in this inhibition. Methods: Neutrophils were incubated with different concentrations of omeprazole and pantoprazole for 30 min and stimulated to migrate with fMLP and IL-8. Treatment toxicity was assessed by MTT assay. The intracellular calcium levels were analyzed in neutrophils pre-treated with omeprazole and pre-loaded with FURA-2AM, when stimulated with fMLP. The activity of p38 MAP Kinase was evaluated by Western blot after treatment with omeprazole. Results: Omeprazole is able to inhibit neutrophil chemotaxis to fMLP and IL-8. Pantoprazole demonstrated the same ability. This inhibitory effect was not due to a toxic effect of the proton pump inhibitors. Inhibition of v-ATPase by bafilomycin did not modify the ability of fMLP or IL-8 to induce neutrophil migration. Omeprazole was also able to decrease intracellular calcium availability. The addition of a potassium ionophore, nigericin, restored the migratory ability, as well as the intracellular calcium levels. The activity of p38 MAP Kinase was decreased in neutrophils pretreated with omeprazole. Conclusion: Proton pump inhibitors promote inhibition of H⁺K⁺ATPase in neutrophils, resulting in cationic flow disturbances through the cellular membrane that, consequently, inhibit migratory and intracellular events such as calcium influx and p38 MAP Kinase activation. Received 4 August 2006; returned for revision 13 September 2006; accepted by M. Parnham 15 September 2006     

Activation of k<Subscript>1</Subscript>-opioid receptor as a method for prevention of ischemic and reperfusion arrhythmias: Role of protein kinase C and K<Subscript>ATP</Subscript> channels

Intravenous pretreatment with κ-opioid receptor antagonist (−)-U-50,488 (1 mg/kg) improved heart resistance to the arrhythmogenic effect of coronary occlusion and reperfusion. Selective κ₁-opioid receptor antagonist norbinaltorphimine and nonselective blocker of peripheral opioid receptors methylnaloxone abolished this antiarrhythmic effect. Preliminary blockade of protein kinase C with chelerythrine or inhibition of ATP-dependent K⁺ channels (K_ATP channels) with glybenclamide abolished the antiarrhythmic effect of κ-opioid receptor activation. Selective inhibitor of sarcolemmal K_ATP channels did not modulate the κ-opioid receptor-mediated increase in cardiac electrical stability. Our results suggest that protein kinase C and mitochondrial K_ATP channels play an important role in the antiarrhythmic effect associated with activation of peripheral κ-opioid receptors. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 2, pp. 145–148, February, 2007     

Persistent sodium current and Na<Superscript>+</Superscript>/H<Superscript>+</Superscript> exchange contributes to the augmentation of the reverse Na<Superscript>+</Superscript>/Ca<Superscript>2+</Superscript> exchange during hypoxia or acute ischemia in ventricular myocytes

The increases in persistent sodium currents (I _Na.P) and Na⁺/H⁺ exchange (NHE) causes intracellular Ca²⁺ overload. The objective of this study was to determine the contribution of I _Na.P and NHE on the hypoxia- or acute ischemia-induced increase in the reverse Na⁺/Ca²⁺ exchange current (HIR- or AIR-I _NCX). I _Na.P and I _NCX in rabbit ventricular myocytes were recorded during hypoxia or acute ischemia, combination of acidosis (pH values were 6.0 intracellularly and 6.8 extracellularly) and hypoxia, using whole-cell patch-clamp techniques. The results indicate that (1) under hypoxic condition, the augmentation of both HIR-I _NCX and I _Na.P was inhibited by TTX (2 to 8 μM) in a concentration-dependent manner. The inhibitions of I _Na,P and HIR-I _NCX reached maximum in the presence of either 4 μM TTX or 10 μM KR-32568 (a NHE inhibitor), respectively. The maximal inhibitions of HIR-I _NCX by 4 μM TTX and 10 μM KR-32568 were 72.54% and 16.89%, respectively. (2) Administration of 2 μM TTX and 10 μM KR-32568 in either order in the same cells decreased HIR-I _NCX by 64.83% and 16.94%, respectively. (3) I _Na.P and the reverse I _NCX were augmented during acute ischemia. TTX (4 μM) and KR-32568 (10 μM) reduced AIR-I _NCX by 73.39% and 24.13%, respectively. (4) Under normoxic condition, veratridine (20 μM) significantly increased I _Na.P and the reverse I _NCX, which was reversed by 4 μM TTX. In conclusion, during hypoxia or acute ischemia, both increased I _Na.P and NHE contribute to the HIR- or AIR-I _NCX with the former playing a major role comparing with the latter.     

Comparison of the effect of adaptation to stress and to high altitude hypoxia on resistance of the heart to reperfusion injury after total ischemia

Research Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR G. N. Kryzhanovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 7, pp. 18–20, July, 1991.     

Cold adaptation modulates Ca<Superscript>2+</Superscript> signaling in brown preadipocytes

One-week cold exposure of mice led to a 2-fold increase in the density of α₁-adrenoceptors in brown adipose tissue. The density of α₁-adrenoceptors returned to normal after adaptation to cold for 2 weeks. The reduced Ca²⁺ signaling in stem cells of brown fat activated via β-adrenoceptors and cAMP was transformed into the Ca²⁺-system induced by α₁-adrenoceptors and similar to that in mature brown adipocytes. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 138, No. 7, pp. 59–62, July, 2004     

Antiarrhythmic effect of heat adaptation in ischemic and reperfusion injury to the heart

Study on a model of 6-day dosed adaptation to heat in rats showed that this adaptation decreased the severity of cardiac arrhythmias during ischemic and reperfusion injury. The duration of arrhythmias decreased not only in the ischemic period, but also under conditions of reperfusion. Adaptation delayed the development of arrhythmias during ischemia, decreased the number of animals with late reperfusion arrhythmias, and improved recovery of the heart after ischemia and reperfusion. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 1, pp. 13–16, January, 2007     

Role of Thy 1,2<Superscript>+</Superscript> Cells in the Regulation of Hemopoiesis during Experimental Neuroses

We studied the direct and stromal cell-mediated effects of bone marrow Thy 1,2⁺ cells on the growth of granulocyte-macrophage and erythroid colonies from the bone marrow of CBA/CaLac mice with experimental neuroses (conflict situation and paradoxical sleep deprivation). Proliferation and differentiation of hemopoietic precursors during neuroses are controlled by regulatory T cells. In conflict situation Thy 1,2⁺ cells stimulate the growth of hemopoietic precursors, which is associated with their direct effect and interaction with adherent cells of the hemopoiesis-inducing microenvironment. The interaction of Thy 1,2⁺ cells with adherent bone marrow cells during paradoxical sleep deprivation stimulates the formation of only granulocyte-macrophage colonies.__________Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 139, No. 6, pp. 608–612, June, 2005     

Mechanism of Inhibition of Acetylcholine Secretion in Newly Formed Mouse Synapses Involving Ca<Superscript>2+</Superscript>-Dependent Kinases and Voltage-Gated K<Superscript>+</Superscript>-Channels

Nifedipine, a blocker of L-type Ca²⁺-channels, increased quantal content of endplate potentials in newly formed nerve-muscle synapses, while R 24571 (calmodulin inhibitor) and KN 62 (inhibitor of calmodulin-dependent kinase II) did not change it. KN 62 suppressed the increase in quantal content of endplate potentials evoked by nifedipine. Similar to nifedipine, chelerythrine and bisindolylmaleimide I (blockers of protein kinase C) increased quantal content of endplate potentials. In the presence of chelerythrine, nifedipine lost its ability to facilitate secretion of neurotransmitter. 4-Aminopyridine, a blocker of voltage-gated potassium channels, increased quantal content of endplate potentials. In the presence of chelerythrine, 4-aminopyridine induced no additional increase in the quantal content of endplate potentials. In its turn, chelerythrine induced no extra facilitation of secretion in the presence of 4-aminopyridine. It is hypothesized that Ca²⁺-dependent inhibition of secretion results from suppression of calmodulin-dependent kinase II and activation of protein kinase C, which potentiates the work of voltage-gated K⁺-channels.     

A Distinct Role of CD4<Superscript>+</Superscript> Th17- and Th17-Stimulated CD8<Superscript>+</Superscript> CTL in the Pathogenesis of Type 1 Diabetes and Experimental Autoimmune Encephalomyelitis

Both CD4(+) Th17-cells and CD8(+) cytotoxic T lymphocytes (CTLs) are involved in type 1 diabetes and experimental autoimmune encephalomyelitis (EAE). However, their relationship in pathogenesis of these autoimmune diseases is still elusive. We generated ovalbumin (OVA)- or myelin oligodendrocyte glycoprotein (MOG)-specific Th17 cells expressing RORγt and IL-17 by in vitro co-culturing OVA-pulsed and MOG(35-55) peptide-pulsed dendritic cells (DC(OVA) and DC(MOG)) with CD4(+) T cells derived from transgenic OTII and MOG-T cell receptor mice, respectively. We found that these Th17 cells when transferred into C57BL/6 mice stimulated OVA- and MOG-specific CTL responses, respectively. To assess the above question, we adoptively transferred OVA-specific Th17 cells into transgenic rat insulin promoter (RIP)-mOVA mice or RIP-mOVA mice treated with anti-CD8 antibody to deplete Th17-stimulated CD8(+) T cells. We demonstrated that OVA-specific Th17-stimulated CTLs, but not Th17 cells themselves, induced diabetes in RIP-mOVA. We also transferred MOG-specific Th17 cells into C57BL/6 mice and H-2K(b-/-) mice lacking of the ability to generate Th17-stimulated CTLs. We further found that MOG-specific Th17 cells, but not Th17-activated CTLs induced EAE in C57BL/6 mice. Taken together, our data indicate a distinct role of Th17 cells and Th17-stimulated CTLs in the pathogenesis of TID and EAE, which may have great impact on the overall understanding of Th17 cells in the pathogenesis of autoimmune diseases.