Telmisartan Activates Endothelial Nitric Oxide Synthase via Ser1177 Phosphorylation in Vascular Endothelial Cells

Because endothelial nitric oxide synthase (eNOS) has anti-inflammatory and anti-arteriosclerotic functions, it has been recognized as one of the key molecules essential for the homeostatic control of blood vessels other than relaxation of vascular tone. Here, we examined whether telmisartan modulates eNOS function through its pleiotropic effect. Administration of telmisartan to mice significantly increased the phosphorylation level of eNOS (Ser1177) in the aortic endothelium, but administration of valsartan had no effect. Similarly, telmisartan treatment of human umbilical vein endothelial cells significantly increased the phosphorylation levels of AMP-activated protein kinase (Thr172) and eNOS and the concentration of intracellular guanosine 3′,5′-cyclic monophosphate (cGMP). Furthermore, pretreatment with a p38 mitogen-activated protein kinase (p38 MAPK) inhibitor suppressed the increased phosphorylation level of eNOS and intracellular cGMP concentration. These data show that telmisartan increases eNOS activity through Ser1177 phosphorylation in vascular endothelial cells mainly via p38 MAPK signaling.     

Endogenous ghrelin and 5-HT regulate interdigestive gastrointestinal contractions in conscious rats

Endogenous ghrelin causes interdigestive contractions of the stomach in rats. In contrast, previous studies showed that 5-HT(3) and 5-HT(4) receptors were involved in regulating intestinal interdigestive contractions. We studied the possible role of endogenous ghrelin and 5-HT regulating interdigestive gastrointestinal (GI) contractions in rats. Four strain gauge transducers were implanted on the antrum, duodenum, and proximal and distal jejunum. After an overnight fast, GI contractions were recorded in freely moving conscious rats and ghrelin receptor antagonists [(d-lys3)GHRP6; 1 micromol/kg], 5-HT(3) antagonists (Ondansetron; 0.5 mg/kg) and 5-HT(4) antagonists (GR 125,487; 1 mg/kg) were administered (bolus iv). To evaluate the relationship between the luminal concentrations of 5-HT and phase III-like contractions of the duodenum, duodenal juice was collected via the intraduodenal catheter. 5-HT content of the duodenal juice was measured by HPLC. (d-lys3)GHRP6 significantly attenuated the occurrence and amplitude of phase III-like contractions of the antrum, but not the duodenum and jejunum. 5-HT(4) antagonists significantly reduced spontaneous phase III-like contractions of the jejunum, without affecting those of the antrum and duodenum. In contrast, 5-HT(3) antagonists did not affect phase III-like contractions in GI tract. Luminal concentration of 5-HT at the phase III-like contraction (36.0 +/- 13.3 ng/ml, n = 9) was significantly higher than that at the phase I-like contractions of the duodenum (4.9 +/- 1.6 ng/ml, n = 9, P < 0.05). It is suggested that released ghrelin from the gastric mucosa mediates gastric phase III-like contractions, whereas 5-HT released from enterochromaffin cells of the duodenal mucosa mediates intestinal phase III-like contractions via 5-HT(4) receptors.     

The amino acid sequence of ferredoxin from the alga Mastigocladuslaminosus

Ferredoxin was purified from the thermophilic blue-green alga, Mastigocladuslaminosus. The physicochemical properties of this ferredoxin are similar to those of other [2Fe-2S] plant ferredoxins except for its unusual thermal stability. The primary structure of the protein was determined and consists of 98 amino acid residues, 5 of which are cysteines. The positions of 4 cysteines which bind the iron atoms of the active centre are identical to those in other ferredoxins. The primary structure of the ferredoxin does not reveal any special features to account for its high thermal stability.     

Apilimod inhibits the production of IL-12 and IL-23 and reduces dendritic cell infiltration in psoriasis

Psoriasis is characterized by hyperplasia of the epidermis and infiltration of leukocytes into both the dermis and epidermis. IL-23, a key cytokine that induces T(H)17 cells, has been found to play a critical role in the pathogenesis of psoriasis. Apilimod is a small-molecule compound that selectively suppresses synthesis of IL-12 and IL-23. An open-label clinical study of oral administration of apilimod was conducted in patients with psoriasis. Substantial improvements in histology and clinical measurements were observed in patients receiving 70 mg QD. The expression of IL-23p19 and IL-12/IL-23p40 in skin lesions was significantly reduced in this dose group, with a simultaneous increase in IL-10 observed. A decrease in the levels of T(H)1 and T(H)17 cytokines/chemokines in skin lesions followed these p19 and p40 changes. In parallel, a reduction in skin-infiltrating CD11c(+) dendritic cells and CD3(+) T cells was seen, with a greater decrease in the CD11c(+) population. This was accompanied by increases in T and B cells, and decreases in neutrophils and eosinophils in the periphery. This study demonstrates the immunomodulatory activity of apilimod and provides clinical evidence supporting the inhibition of IL-12/IL-23 synthesis for the treatment of T(H)1- and T(H)17-mediated inflammatory diseases.     

C17,20-lyase inhibitors I. Structure-based de novo design and SAR study of C17,20-lyase inhibitors

Novel nonsteroidal C(17,20)-lyase inhibitors were synthesized using de novo design based on its substrate, 17 alpha-hydroxypregnenolone, and several compounds exhibited potent C(17,20)-lyase inhibition. However, in vivo activities were found to be short-lasting, and in order to improve the duration of action, a series of benzothiophene derivatives were evaluated. As a result, compounds 9h, (S)-9i, and 9k with nanomolar enzyme inhibition (IC(50)=4-9 nM) and 9e (IC(50)=27 nM) were identified to have powerful in vivo efficacy with extended duration of action. The key structural determinants for the in vivo efficacy were demonstrated to be the 5-fluoro group on the benzothiophene ring and the 4-imidazolyl moiety. Superimposition of 9k and 17 alpha-hydroxypregnenolone demonstrated their structural similarity and enabled rationalization of the pharmacological results. In addition, selected compounds were also identified to be potent inhibitors of human enzyme with IC(50) values of 20-30 nM.     

A novel neurotoxoid vaccine prevents mucosal botulism

The threat posed by botulism, classically a food- and waterborne disease with a high morbidity and mortality, has increased exponentially in an age of bioterrorism. Because botulinum neurotoxin (BoNT) could be easily disseminated by terrorists using an aerosol or could be used to contaminate the food or water supply, the Centers for Disease Control and Prevention and the National Institute of Allergy and Infectious Diseases has classified it as a category A agent. Although clearly the development of a safe and effective mucosal vaccine against this toxin should be a high priority, essentially no studies to date have assessed mucosal immune responses to this disease. To bridge this gap in our knowledge, we immunized mice weekly for 4 wk with nasal doses of BoNT type A toxoid and a mutant of cholera toxin termed E112K. We found elevated levels of BoNT-specific IgG Abs in plasma and of secretory IgA Abs in external secretions (nasal washes, saliva, and fecal extracts). When mice given nasal BoNT vaccine were challenged with 4 x 10(3) LD50 of BoNT type A (BoNT/A) via the i.p. route, complete protection was seen, while naive mice given the same dosage died within 2 h. To further confirm the efficacy of this nasal BoNT vaccine, an oral LD50 was determined. When mice were given an oral challenge of 5 microg (2 x oral LD50) of progenitor BoNT/A, all immunized mice survived beyond 5 days, while nonimmunized mice did not. The fecal extract samples from nasally vaccinated mice were found to contain neutralizing secretory IgA Abs. Taken together, these results show that nasal BoNT/A vaccine effectively prevents mucosal BoNT intoxication.     

Retardation of removal of radiation-induced apoptotic cells in developing neural tubes in macrophage galactose-type C-type lectin-1-deficient mouse embryos

MGL1/CD301a is a C-type lectin that recognizes galactose and N-acetylgalactosamine as monosaccharides and is expressed on limited populations of macrophages and dendritic cells at least in adult mice. In this study, pregnant mice with Mgl1+/- genotype were mated with Mgl1+/- or Mgl1-/- genotype males, and the embryos were used to assess a hypothesis that this molecule plays an important role in the clearance of apoptotic cells. After X-ray irradiation at 1 Gy of developing embryos at 10.5 days post coitus (d.p.c.), the number of Mgl1-/- pups was significantly reduced as compared with Mgl1+/+ pups. Distributions of MGL1-positive cells, MGL2-positive cells, and apoptotic cells were histologically examined in irradiated Mgl1+/+ embryos. MGL1-positive cells were detected in the neural tube in which many cells undergo apoptosis, whereas MGL2-positive cells were not observed. Biotinylated recombinant MGL1 bound a significant portion of the apoptotic cells. When Mgl1+/+ and Mgl1-/- embryos were examined for the presence of apoptotic cells, similar numbers of apoptotic cells gave rise, but the clearance of these cells was slower in Mgl1-/- embryos than in Mgl1+/+ embryos. These results strongly suggest that MGL1/CD301a is involved in the clearance of apoptotic cells. This process should be essential in the repair and normal development of X-ray-irradiated embryos.     

Contribution of microsomal cytochrome b5 electron transport system coupled with Δ5-3β-hydroxysteroid dehydrogenase to androgen synthesis from progesterone

Cytochromes P-450 and $\text{b}$₅ were observed in the microsomal fraction of interstitial tissue of rat testes. Microsomal cytochrome $\text{b}$₅ was reduced by the NADH coupled with the activities of Δ⁵-3β-hydroxysteroid dehydrogenase with Δ⁵-Δ⁴ isomerase through conversion of pregnenolone to progesterone. Activities of NADPH-supported 17α-hydroxylase and C-17-C-20 lyase which converted progesterone to androstenedione were stimulated by either the presence of NADH or the oxidative reaction by the dehydrogenase upon Δ⁵-3β-hydroxysteroids. Androstenedione production enhanced by the reaction of the dehydrogenase was decreased by addition of the antibody against NADH-cytochrome $\text{b}$₅ reductase which was purified from rat hepatic microsomes, suggesting the active participation of cytochrome $\text{b}$₅ in the androgen synthesis.