Soluble epoxide hydrolase inhibitor promotes immunomodulation to inhibit bone resorption.

BACKGROUND AND OBJECTIVE: Soluble epoxide hydrolase (sEH) is an enzyme in the arachidonate cascade which converts epoxy fatty acids (EpFAs), such as epoxyeicosatrienoic acids (EETs) produced by cytochrome P450 enzymes, to dihydroxy-eicosatrienoic acids. In the last 20 years with the development of inhibitors to sEH it has been possible to increase the levels of EETs and other EpFAs in in vivo models. Recently, studies have shown that EETs play a key role in blocking inflammation in a bone resorption process, but the mechanism is not clear. In the current study we used the sEH inhibitor (1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea [TPPU]) to investigate the immunomodulatory effects in a mouse periodontitis model. MATERIAL AND METHODS: Mice were infected on days 0, 2, and 4 with Aggregatibacter actinomycetemcomitans and divided into groups (n = 6) that were treated orally, daily for 15 days, with 1 mg/kg of TPPU. Then, the mice were killed and their jaws were analyzed for bone resorption using morphometry. Immunoinflammatory markers in the gingival tissue were analyzed by microarray PCR or western blotting. RESULTS: Infected mice treated with TPPU showed lower bone resorption than infected mice without treatment. Interestingly, infected mice showed increased expression of sEH; however, mice treated with TPPU had a reduction in expression of sEH. Besides, several proinflammatory cytokines and molecular markers were downregulated in the gingival tissue in the group treated with 1 mg/kg of TPPU. CONCLUSION: The sEH inhibitor, TPPU, showed immunomodulatory effects, decreasing bone resorption and inflammatory responses in a bone resorption mouse model.

The effect of p.Arg25Cys alteration in NKX2-5 on conotruncal heart anomalies: mutation or polymorphism?

Heterozygous mutations in the NKX2-5 gene of patients with various congenital heart defects have been reported. Most of the congenital heart defects associated with the mutations in the NKX2-5 gene are conotruncal heart anomalies, primarily the tetralogy of Fallot. In this study, the authors screened 72 Turkish children with conotruncal heart anomalies and 185 healthy control subjects to find the NKX2-5 alterations. They found one previously documented NKX2-5 missense alteration, heterozygous c.73C>T (p.Arg25Cys), in a 10-year-old boy with tetralogy of Fallot. The same heterozygous alteration was found also in the patient's healthy father and in two unrelated persons in the healthy control group. The current study shows for the first time the presence of p.Arg25Cys in healthy control subjects other than African Americans. These results show that no genetic support exists for the pathogenecity of this alteration, although a previous in vitro study and theoretical predictions suggest a structural/functional difference in the altered protein region.

Evaluation of the neutralizing capacity of Androctonus crassicauda (Olivier, 1807) antivenom against Leiurus quinquestriatus (Ehrenberg, 1928) venom (Scorpiones: Buthidae)

The two most venomous species of the family Buthidae, Leiurus quinquestriatus and Androctonus crassicauda, are found in Africa and in the Middle East. Potency and paraspecific activities of A. crassicauda antivenom (RSHC anti-Ac) were tested against L. quinquestriatus venom. The sera produced by Refik Saydam Hygiene Center (RSHC) showed strong reactivity against the venoms of A. crassicauda and L. quinquestriatus in western blotting and dot-blot analysis. RSHC anti-Ac presents immunoactivity and neutralizing potential against Leiurus quinquestriatus venom. Neutralization capacity of antivenom was found to be 400 µL against 40 minimum lethal doses (MLD) of A. crassicauda scorpion venom and 10 MLD of L. quinquestriatus venom. This study indicates that the RSHC anti-Ac could be used for treating L. quinquestriatus stings.(AU)

Isolation and characterization of a novel type of neurotoxic peptide from the venom of the South African scorpion Parabuthus transvaalicus (Buthidae).

The venom of the South African scorpion Parabuthus transvaalicus was characterized using a combination of mass spectrometry and RP-HPLC separation and bioassays. The crude venom was initially separated into 10 fractions. A novel, moderately toxic but very high abundance peptide (birtoxin) of 58 amino-acid residues was isolated, identified and characterized. Each purification step was followed by bioassays and mass spectroscopy. First a C4 RP-HPLC column was used, then a C18 RP Microbore column purification resulted in > 95% purity in the case of birtoxin from a starting material of 230 microg of crude venom. About 12-14% of the D214 absorbance of the total venom as observed after the first chromatography step was composed of birtoxin. This peptide was lethal to mice at low microgram quantities and it induced serious symptoms including tremors, which lasted up to 24 h post injection, at submicrogram amounts. At least seven other fractions that showed different activities including one fraction with specificity against blowfly larvae were identified. Identification of potent components is an important step in designing and obtaining effective anti-venom. Antibodies raised against the critical toxic components have the potential to block the toxic effects and reduce the pain associated with the scorpion envenomation. The discovery of birtoxin, a bioactive long chain neurotoxin peptide with only three disulfide bridges, offers new insight into understanding the role of conserved disulfide bridges with respect to scorpion toxin structure and function.

Isolation and characterization of a novel lepidopteran-selective toxin from the venom of South Indian red scorpion, Mesobuthus tamulus.

BACKGROUND: Scorpion venom contains insect and mammal selective toxins. We investigated the venom of the South Indian red scorpion, Mesobuthus tamulus for the purpose of identifying potent insecticidal peptide toxins. RESULTS: A lepidopteran-selective toxin (Buthus tamulus insect toxin; ButaIT) has been isolated from this venom. The primary structure analysis reveals that it is a single polypeptide composed of 37 amino acids cross-linked by four disulfide bridges with high sequence homology to other short toxins such as Peptide I, neurotoxin P2, Lqh-8/6, chlorotoxin, insectotoxin I5A, insect toxin 15 and insectotoxin I1. Three dimensional modeling using Swiss automated protein modeling server reveals that this toxin contains a short alpha-helix and three antiparallel beta-strands, similar to other short scorpion toxins. This toxin is selectively active on Heliothis virescens causing flaccid paralysis but was non-toxic to blowfly larvae and mice. CONCLUSION: This is the first report of a Heliothine selective peptide toxin. Identification of diverse insect selective toxins offer advantages in employing these peptides selectively for pest control.