Nitric oxide synthase in the glossopharyngeal and vagal afferent pathway of a teleost, Takifugu niphobles

To examine the presence of nitric oxide synthase (NOS) in the sensory system of the glossopharyngeal and vagus nerves of teleosts, nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) activity and immunoreactivity for NOS were examined in the puffer fish Takifugu niphobles. The nitrergic sensory neurons were located in the ganglia of both the glossopharyngeal and the vagal nerves. In the vagal ganglion, positive neurons were found in the subpopulations for the branchial rami and the coelomic visceral ramus, but not for the posterior ramus or the lateral line ramus. In the medulla, nitrergic afferent terminals were found in the glossopharyngeal lobe, the vagal lobe, and the commissural nucleus. In the gill structure, the nitrergic nerve fibers were seen in the nerve bundles running along the efferent branchial artery of all three gill arches. These fibers appeared to terminate in the proximal portion of the efferent filament arteries of three gill arches. On the other hand, autonomic neurons innervating the gill arches were unstained. These results suggest that nitrergic sensory neurons in the glossopharyngeal and vagal ganglia project their peripheral processes through the branchial rami to a specific portion of the branchial arteries, and they might play a role in baroreception of this fish. A possible role for nitric oxide (NO) in baroreception is also discussed.     

Angiotensin II and tumor necrosis factor-alpha synergistically promote monocyte chemoattractant protein-1 expression: roles of NF-kappaB, p38, and reactive oxygen species

We examined whether ANG II and TNF-alpha cooperatively induce vascular inflammation using the expression of monocyte chemoattractant protein (MCP)-1 as a marker of vascular inflammation. ANG II and TNF-alpha stimulated MCP-1 expression in a synergistic manner in vascular smooth muscle cells. ANG II-induced MCP-1 expression was potently inhibited to a nonstimulated basal level by blockade of the p38-dependent pathway but only partially inhibited by blockade of the NF-kappaB-dependent pathway. In contrast, TNF-alpha-induced MCP-1 expression was potently suppressed by blockade of NF-kappaB activation but only modestly suppressed by blockade of p38 activation. ANG II- and TNF-alpha-induced activation of NF-kappaB- and p38-dependent pathways was partially inhibited by pharmacological inhibitors of ROS production. Furthermore, ANG II- and TNF-alpha-stimulated MCP-1 expression was partially suppressed by ROS inhibitors. We also examined whether endogenous ANG II and TNF-alpha cooperatively promote vascular inflammation in vivo using a wire injury model of the rat femoral artery. Blockade of both ANG II and TNF-alpha further suppressed neointimal formation, macrophage infiltration, and MCP-1 expression in an additive manner compared with blockade of ANG II or TNF-alpha alone. These results suggested that ANG II and TNF-alpha synergistically stimulate MCP-1 expression via the utilization of distinct intracellular signaling pathways (p38- and NFkappaB-dependent pathways) and that these pathways are activated in ROS-dependent and -independent manners. These results also suggest that ANG II and TNF-alpha cooperatively stimulate vascular inflammation in vivo as well as in vitro.     

Phytoalexin induction in the sapwood of plants of the Maloideae (Rosaceae): Biphenyls or dibenzofurans

Following fungal inoculation or natural infection, five biphenyl phytoalexins (aucuparin and its 2′ and 4′ oxygenated derivatives) were induced variously in the sapwood of Aronia, Chaenomeles, Eriobotrya, Malus(three spp.) and of Sorbus aucuparia. By contrast, 14 dibenzofuran phytoalexins were induced variously in sapwood of Cotoneaster (7 spp.), Crateagus, Cydonia, Mespilus, Photinia, Pseudocydonia, Pyracantha, Pyrus and two Sorbus spp. (S. chamaemespilum and S. domestica). These were five cotonefurans, three eriobofurans, five pyrufurans and a 2,3,4,7,8-pentaoxygenated dibenzofuran trimethyl ether. No plant has yet been found to produce both types of phytoalexin, although o-hydroxybiphenyls are theoretically precursors of the dibenzofurans. The ability to synthesize either biphenyls or dibenzofurans appears to be genus-specific, except in the case of Sorbus. In 18 of the 38 species tested, these phytoalexins were accompanied by constitutive antifungal phenolics, most of which appeared to be released from bound (glycosidic) forms during the infection process. These were identified variously as hydroquinone, p-hydroxyacetophenone, acetovanillone, 5,7-dihydroxychromone, chrysin, sakuranetin and naringenin. Woody members of the subfamilies Prunoideae and Spiraeoideae failed to yield any phytoalexins on induction, but did contain constitutive antifungal compounds. The limited frequency of the phytoalexin response within the family as a whole is considered in relation to the accumulation of constitutive antifungal agents in these plants.     

Mouse genetics identifies unique and overlapping functions of fibroblast growth factor receptors in keratinocytes

Fibroblast growth factors (FGFs) are key regulators of tissue development, homeostasis and repair, and abnormal FGF signalling is associated with various human diseases. In human and murine epidermis, FGF receptor 3 (FGFR3) activation causes benign skin tumours, but the consequences of FGFR3 deficiency in this tissue have not been determined. Here, we show that FGFR3 in keratinocytes is dispensable for mouse skin development, homeostasis and wound repair. However, the defect in the epidermal barrier and the resulting inflammatory skin disease that develops in mice lacking FGFR1 and FGFR2 in keratinocytes were further aggravated upon additional loss of FGFR3. This caused fibroblast activation and fibrosis in the FGFR1/FGFR2 double‐knockout mice and even more in mice lacking all three FGFRs, revealing functional redundancy of FGFR3 with FGFR1 and FGFR2 for maintaining the epidermal barrier. Taken together, our study demonstrates that FGFR1, FGFR2 and FGFR3 act together to maintain epidermal integrity and cutaneous homeostasis, with FGFR2 being the dominant receptor.     

Fmoc-based solid-phase synthesis of GPR54-agonistic pentapeptide derivatives containing alkene- and fluoroalkene-dipeptide isosteres

Fmoc-protected Phe-Gly-type (Z)-alkene dipeptide isostere (ADI) and (E)-fluoroalkene dipeptide isostere (FADI) were synthesized and applied to Fmoc-based solid-phase peptide synthesis (SPPS). These cis-peptide bond mimetics were introduced into a bioactive pentapeptide [H-Amb-Phe-Gly-Leu-Arg-Trp-NH(2); Amb = 4-(aminomethyl) benzoic acid], which has potent GPR54 agonistic activity. The resulting pentapeptide derivatives showed low GPR54 agonistic activity, as compared with the parent peptide and (E)-ADI-containing derivative. This suggests that the trans-amide conformer of Phe-Gly peptide bond of the parent peptide would be significantly important for bioactivity. Contrary to our expectations, a (Z)-FADI-containing derivative exhibited essentially no activity, revealing the necessity of critical validation of FADI-bioisosterism.