Distinct regions of Galpha13 participate in its regulatory interactions with RGS homology domain-containing RhoGEFs

Galpha12 and Galpha13 transduce signals from G protein-coupled receptors to RhoA through RhoGEFs containing an RGS homology (RH) domain, such as p115 RhoGEF or leukemia-associated RhoGEF (LARG). The RH domain of p115 RhoGEF or LARG binds with high affinity to active forms of Galpha12 and Galpha13 and confers specific GTPase-activating protein (GAP) activity, with faster GAP responses detected in Galpha13 than in Galpha12. At the same time, Galpha13, but not Galpha12, directly stimulates the RhoGEF activity of p115 RhoGEF or nonphosphorylated LARG in reconstitution assays. In order to better understand the molecular mechanism by which Galpha13 regulates RhoGEF activity through interaction with RH-RhoGEFs, we sought to identify the region(s) of Galpha13 involved in either the GAP response or RhoGEF activation. For this purpose, we generated chimeras between Galpha12 and Galpha13 subunits and characterized their biochemical activities. In both cell-based and reconstitution assays of RhoA activation, we found that replacing the carboxyl-terminal region of Galpha12 (residues 267-379) with that of Galpha13 (residues 264-377) conferred gain-of-function to the resulting chimeric subunit, Galpha12C13. The inverse chimera, Galpha13C12, exhibited basal RhoA activation which was similar to Galpha12. In contrast to GEF assays, GAP assays showed that Galpha12C13 or Galpha13C12 chimeras responded to the GAP activity of p115 RhoGEF or LARG in a manner similar to Galpha12 or Galpha13, respectively. We conclude from these results that the carboxyl-terminal region of Galpha13 (residues 264-377) is essential for its RhoGEF stimulating activity, whereas the amino-terminal alpha helical and switch regions of Galpha12 and Galpha13 are responsible for their differential GAP responses to the RH domain.     

Effects of CH-19 Sweet, a non-pungent cultivar of red pepper, on sympathetic nervous activity, body temperature, heart rate, and blood pressure in humans

We investigated the changes in autonomic nervous activity, body temperature, blood pressure (BP), and heart rate (HR) after intake of the non-pungent pepper CH-19 Sweet and of hot red pepper in humans to elucidate the mechanisms of diet-induced thermogenesis (DIT) due to CH-19 Sweet. We found that CH-19 Sweet activates the sympathetic nervous system (SNS) and enhances thermogenesis as effectively as hot red pepper, ant that the heat loss effect due to CH-19 Sweet is weaker than that due to hot red pepper. Furthermore, we found that intake of CH-19 Sweet does not affect systolic BP or HR, while hot red pepper transiently elevates them. These results indicate that DIT due to CH-19 Sweet can be induced via the activation of SNS as well as hot red pepper, but that the changes in BP, HR, and heat loss effect are different between these peppers.     

Effect of dietary oils on lymphocyte immunological activity in psychologically stressed mice

Psychological stress has been shown to modulate immune functions. In this study, we investigated the effect of dietary oils (olive oil, soybean oil, and fish oil) on the social isolation stress-induced modulation of lymphocyte immunological activities in mice. In olive oil-fed, but not soybean oil- or fish oil-fed, mice, a 2-week isolation stress decreased the lymphocyte proliferative response, reduced the interferon-gamma and interleukin (IL)-10 secretions and increased the IL-4 secretion by lymphocytes. The isolation stress reduced the arachidonic acid content of lymphocytes markedly, moderately, and not at all in the olive oil-, soybean oil-, and fish oil-fed mice, respectively. In the olive oil-fed, but not soybean oil- or fish oil-fed, mice, the isolation stress up-regulated the expression level of mRNA for splenic heat-shock protein 70 and increased lymphocyte sensitivity to the antiproliferative effect of corticosterone. This is the first demonstration that effect of psychological stress on lymphocyte immunological activities can vary depending upon the dietary fatty acid composition.     

A role of a lymphocyte tryptase, granzyme A, in experimental ulcerative colitis

In the large-intestinal mucosae of rats orally administered dextran sulfate sodium, which induces an enteritis resembling ulcerative colitis (UC), the activity for granzyme A, a lymphocyte tryptase, increased at an earlier stage than that at which UC markers (growth-regulated gene product/cytokine-induced neutrophil chemoattractant-1 and caspase-3) increased. This suggests involvement of the enzyme in the exacerbation and perpetuation of enteritis.     

Preparation of 2-C- and 3-C-cyano-2-enopyranoside derivatives and their epoxidation

Methyl 4,6-O-benzylidene-2-C- and 3-C-cyano-2,3-dideoxy-D-erythro-hex-2-enopyranosides and -2-enitols were prepared and their epoxidation was performed.     

Menstrual blood-derived cells confer human dystrophin expression in the murine model of Duchenne muscular dystrophy via cell fusion and myogenic transdifferentiation

Duchenne muscular dystrophy (DMD), the most common lethal genetic disorder in children, is an X-linked recessive muscle disease characterized by the absence of dystrophin at the sarcolemma of muscle fibers. We examined a putative endometrial progenitor obtained from endometrial tissue samples to determine whether these cells repair muscular degeneration in a murine mdx model of DMD. Implanted cells conferred human dystrophin in degenerated muscle of immunodeficient mdx mice. We then examined menstrual blood–derived cells to determine whether primarily cultured nontransformed cells also repair dystrophied muscle. In vivo transfer of menstrual blood–derived cells into dystrophic muscles of immunodeficient mdx mice restored sarcolemmal expression of dystrophin. Labeling of implanted cells with enhanced green fluorescent protein and differential staining of human and murine nuclei suggest that human dystrophin expression is due to cell fusion between host myocytes and implanted cells. In vitro analysis revealed that endometrial progenitor cells and menstrual blood–derived cells can efficiently transdifferentiate into myoblasts/myocytes, fuse to C2C12 murine myoblasts by in vitro coculturing, and start to express dystrophin after fusion. These results demonstrate that the endometrial progenitor cells and menstrual blood–derived cells can transfer dystrophin into dystrophied myocytes through cell fusion and transdifferentiation in vitro and in vivo.     

Aspergillus takadae,a novel heterothallic species of Aspergillus section Fumigati isolated from soil in China

Aspergillus takadae is characterized by its heterothallic reproduction, pale yellow cleistothecia, broadly lenticular ascospores with two short equatorial crests and smooth convex surfaces, and broadly ellipsoidal to ovate conidia with a smooth wall. The validation of these novel species is supported further by the analyses of the β-tubulin, calmodulin, actin, and RPB2 sequences. In addition, the phylogenetic tree and DDBJ accession numbers of all the species of Aspergillus section Fumigati are presented. We report on the crossing of A. takadae species and the result of crossing A. takadae with a closely related species, A. spathulatus.