Protection of endothelial integrity has been recognized as a frontline approach to alleviating sepsis progression, yet no effective agent for preserving endothelial integrity is available. Using an unusual anti-angiopoietin 2 (ANG2) antibody, ABTAA (ANG2-binding and TIE2-activating antibody), we show that activation of the endothelial receptor TIE2 protects the vasculature from septic damage and provides survival benefit in three sepsis mouse models. Upon binding to ANG2, ABTAA triggers clustering of ANG2, assembling an ABTAA/ANG2 complex that can subsequently bind and activate TIE2. Compared with a conventional ANG2-blocking antibody, ABTAA was highly effective in augmenting survival from sepsis by strengthening the endothelial glycocalyx, reducing cytokine storms, vascular leakage, and rarefaction, and mitigating organ damage. Together, our data advance the role of TIE2 activation in ameliorating sepsis progression and open a potential therapeutic avenue for sepsis to address the lack of sepsis-specific treatment.
Glucagon-like peptide-1-(7-36) (GLP-1) is a hormone derived from the proglucagon molecule, which is considered a highly desirable antidiabetic agent mainly due to its unique glucose-dependent stimulation of insulin secretion profiles. However, the development of a GLP-1-based pharmaceutical agent has a severe limitation due to its very short half-life in plasma, being primarily degraded by dipeptidyl peptidase IV (DPP-IV) enzyme. To overcome this limitation, in this article we propose a novel and potent DPP-IV-resistant form of a poly(ethylene glycol)-conjugated GLP-1 preparation and its pharmacokinetic evaluation in rats. Two series of mono-PEGylated GLP-1, (i) N-terminally modified PEG(2k)-N(ter)-GLP-1 and (ii) isomers of Lys(26), Lys(34) modified PEG(2k)-Lys-GLP-1, were prepared by using mPEG-aldehyde and mPEG-succinimidyl propionate, respectively. To determine the optimized condition for PEGylation, the reactions were monitored at different pH buffer and time intervals by RP-HPLC and MALDI-TOF-MS. The in vitro insulinotropic effect of PEG(2k)-Lys-GLP-1 showed comparable biological activity with native GLP-1 (P = 0.11) in stimulating insulin secretion in isolated rat pancreatic islet and was significantly more potent than the PEG(2k)-N(ter)-GLP-1 (P < 0.05) that showed a marked reduced potency. Furthermore, PEG(2k)-Lys-GLP-1 was clearly resistant to purified DPP-IV in buffer with 50-fold increased half-life compared to unmodified GLP-1. When PEG(2k)-Lys-GLP-1 was administered intravenously and subcutaneously into rats, PEGylation improved the half-life, which resulted in substantial improvement of the mean plasma residence time as a 16-fold increase for iv and a 3.2-fold increase for sc. These preliminary results suggest a site specifically mono-PEGylated GLP-1 greatly improved the pharmacological profiles; thus, we anticipated that it could serve as potential candidate as an antidiabetic agent for the treatment of non-insulin-dependent diabetes patients.
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