Soluble dipeptidyl peptidase-4 induces microvascular endothelial dysfunction through proteinase-activated receptor-2 and thromboxane A2 release
2区 · 医学
作者: Romacho, Tania ; Vallejo, Susana ; Villalobos, Laura A. ; Wronkowitz, Nina ; Indrakusuma, Ira ; Sell, Henrike ; Eckel, Jueergen ; Sanchez-Ferrer, Carlos F. ; Peiro, Concepcion
Dipeptidyl peptidase-4 (DPP4) is a key protein in glucose homeostasis and a pharmacological target in type 2 diabetes mellitus. This study explored whether the novel adipokine soluble DPP4 (sDPP4) can cause endothelial dysfunction, an early marker of impaired vascular reactivity.
Reactivity was studied in mesenteric arteries from 3-month-old female mice, using a small vessel myograph. Thromboxane A2 (TXA2) release was explored in cultured human coronary artery endothelial cells by enzyme immunoassay.
Neither the contractility to noradrenaline nor the endothelium-independent relaxations induced by sodium nitroprusside were modified by sDPP4. However, sDPP4 impaired in a concentration-dependent manner the endothelium-dependent relaxation elicited by acetylcholine. The DPP4 inhibitors K579 and linagliptin prevented the defective relaxation induced by sDPP4, as did the protease-activated receptor 2 (PAR2) inhibitor GB83. Downstream of PAR2, the cyclooxygenase (COX) inhibitor indomethacin, the COX2 inhibitor celecoxib or the thromboxane receptors blocker SQ29548 prevented the deleterious effects of sDPP4. Accordingly, sDPP4 triggered the release of TXA2 by endothelial cells, whereas TXA2 release was prevented by inhibiting DPP4, PAR2 or COX.
In summary, these findings reveal sDPP4 as a direct mediator of endothelial dysfunction, acting through PAR2 activation and the release of vasoconstrictor prostanoids. By interfering with these actions, DPP4 inhibitors might help preserving endothelial function in the context of cardiometabolic diseases.
2014-06-01·Digestive Diseases and Sciences3区 · 医学
Dipeptidyl Peptidase IV Inhibition Prevents the Formation and Promotes the Healing of Indomethacin-Induced Intestinal Ulcers in Rats
3区 · 医学
作者: Inoue, Takuya ; Higashiyama, Masaaki ; Kaji, Izumi ; Rudenkyy, Sergiy ; Higuchi, Kazuhide ; Guth, Paul H. ; Engel, Eli ; Kaunitz, Jonathan D. ; Akiba, Yasutada
BACKGROUNDS AND AIMS:
We studied the intestinotrophic hormone glucagon-like peptide-2 (GLP-2) as a possible therapy for non-steroidal anti-inflammatory drug (NSAID)-induced intestinal ulcers. Luminal nutrients release endogenous GLP-2 from enteroendocrine L cells. Since GLP-2 is degraded by dipeptidyl peptidase IV (DPPIV), we hypothesized that DPPIV inhibition combined with luminal administration of nutrients potentiates the effects of endogenous GLP-2 on intestinal injury.
Intestinal injury was induced by indomethacin (10 mg/kg, sc) in fed rats. The long-acting DPPIV inhibitor K579 was given intragastrically (ig) or intraperitoneally (ip) before or after indomethacin treatment. L-Alanine (L-Ala) and inosine 5'-monophosphate (IMP) were co-administered ig after the treatment.
Indomethacin treatment induced intestinal ulcers that gradually healed after treatment. Pretreatment with ig or ip K579 given at 1 mg/kg reduced total ulcer length, whereas K579 at 3 mg/kg had no effect. Exogenous GLP-2 also reduced intestinal ulcers. The preventive effect of K579 was dose-dependently inhibited by a GLP-2 receptor antagonist. Daily treatment with K579 (1 mg/kg), GLP-2, or L-Ala + IMP after indomethacin treatment reduced total ulcer length. Co-administration (ig) of K579 and L-Ala + IMP further accelerated intestinal ulcer healing.
DPPIV inhibition and exogenous GLP-2 prevented the formation and promoted the healing of indomethacin-induced intestinal ulcers, although high-dose DPPIV inhibition reversed the preventive effect. Umami receptor agonists also enhanced the healing effects of the DPPIV inhibitor. The combination of DPPIV inhibition and luminal nutrient-induced GLP-2 release may be a useful therapeutic tool for the treatment of NSAIDs-induced intestinal ulcers.
DOCLASP - Docking ligands to target proteins using spatial and electrostatic congruence extracted from a known holoenzyme and applying simple geometrical transformations.
作者: Sandeep Chakraborty
The ability to accurately and effectively predict the interaction between proteins and small drug-like compounds has long intrigued researchers for pedagogic, humanitarian and economic reasons. Protein docking methods (AutoDock, GOLD, DOCK, FlexX and Glide to name a few) rank a large number of possible conformations of protein-ligand complexes using fast algorithms. Previously, it has been shown that structural congruence leading to the same enzymatic function necessitates the congruence of electrostatic properties (CLASP). The current work presents a methodology for docking a ligand into a target protein, provided that there is at least one known holoenzyme with ligand bound - DOCLASP (Docking using CLASP). The contact points of the ligand in the holoenzyme defines a motif, which is used to query the target enzyme using CLASP. If there are no significant matches, the ligand cannot be docked in the protein. Otherwise, the holoenzyme and the target protein are superimposed based on congruent atoms. The same linear and rotational transformations are also applied to the ligand, thus creating a unified coordinate framework having the holoenzyme, the ligand and the target enzyme. This provides the docked ligand in the target enzyme. Previously, CLASP was used to predict and validate (in vivo) the inhibition of phosphoinositide-specific phospholipase C (PI-PLC) from Bacillus cereus by two dipeptidyl peptidase-IV (DPP4) inhibitors - vildagliptin and K-579. In the current work, vildagliptin was docked to the PI-PLC structure complexed with myo-inositol using DOCLASP. The docked ligand is free from steric clashes and interacts with the same side chain residues that bind myo-inositol, providing corroboration of the validity of the proposed methodology.