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Angiotensin (Ang) II participates in the pathogenesis of heart failure through induction of cardiac hypertrophy. Ang II-induced hypertrophic growth of cardiomyocytes is mediated by nuclear factor of activated T cells (NFAT), a Ca2+-responsive transcriptional factor. It is believed that phospholipase C (PLC)-mediated production of inositol-1,4,5-trisphosphate (IP3) is responsible for Ca2+ increase that is necessary for NFAT activation. However, we demonstrate that PLC-mediated production of diacylglycerol (DAG) but not IP3 is essential for Ang II-induced NFAT activation in rat cardiac myocytes. NFAT activation and hypertrophic responses by Ang II stimulation required the enhanced frequency of Ca2+ oscillation triggered by membrane depolarization through activation of DAG-sensitive TRPC channels, which leads to activation of L-type Ca2+ channel. Patch clamp recordings from single myocytes revealed that Ang II activated DAG-sensitive TRPC-like currents. Among DAG-activating TRPC channels (TRPC3, TRPC6, and TRPC7), the activities of TRPC3 and TRPC6 channels correlated with Ang II-induced NFAT activation and hypertrophic responses. These data suggest that DAG-induced Ca2+ signaling pathway through TRPC3 and TRPC6 is essential for Ang II-induced NFAT activation and cardiac hypertrophy. [ABSTRACT FROM AUTHOR]

In the accompanying paper, the resistance to infections with HSV type 1 (HSV-1) and Candida albicans was improved in thermally injured mice treated with benzoylmesaconine (BEN), an aconitine-hydrolysate isolated from heated Aconiti tuber, or inoculated with splenic CD4+ T cells from BEN-treated mice (BEN T cells). In this paper, therefore, the antiviral mechanism of BEN T cells (or BEN) on the improved resistance of burned mice to the HSV-1 infection was studied. Burn-associated CD8+ CD11b+ TCRγ/δ+ type-2 T cells have been shown to be a key on the increased susceptibility of thermally injured mice to infection with HSV-1 or C. albicans. The susceptibility of T6S-mice, mice inoculated with 1 × 106 cells/mouse of T6S cells (a clone of burn-associated type-2 T cells), to HSV-1 infection was similar to that of thermally injured mice. The adoptive transfer of BEN T cells to T6S-mice restores their impaired resistance to HSV-1 infection. The type-2 cytokine levels in sera of T6S-mice were decreased after inoculation of BEN T cells. BEN T cells inhibited the type-2 cytokine production by T6S cells when they were cocultured in vitro. BEN T cells, characterized as CD4+ CD28+ TCRα/β+ Vicia villosa (VV) lectin-adherent T cells, showed non-specific ability to inhibit the cytokine production by various type-2 T cells. From the results of the cytokine-producing profile, BEN T cells were shown to be a different subset of CD4+ T cells from Th1 and Th2 cells, although these three CD4+ T cells had similar properties phenotypically. BEN T cells were induced in normal mice 1–4 days after the oral treatment of BEN (1 μg/kg or more). These results suggest that, through the induction of antagonistic CD4+ T cells against burn-associated type-2 T cells, BEN may improve the resistance of T6S-mice (or thermally injured mice) to the... [ABSTRACT FROM AUTHOR]

Experience with two cases of psittacosis is described here in which the number of γδ T cell receptor-positive T lymphocytes (γδ T cell) in the bronchoalveolar lavage fluid was markedly increased (25.1 and 66.9%) and CD8+ T cells were also increased with reversal of the CD4/CD8 ratio. These values improved to the normal range along with recovery of their radiographical findings. The present findings suggest that γδ T cells may play an important role in protection from lung injury caused by Chlamydia psittaci infection. [ABSTRACT FROM AUTHOR]