The synthetic LPS binding peptide 19-2.5 interferes with clotting and prevents degradation of high molecular weight kininogen in plasma

Abstract

Sepsis and septic shock are life-threatening conditions and remain an important medical problem, emphasizing the need to identify novel therapeutic approaches. Coagulation dysfunction, hypotension, disturbed microcirculation and multiorgan failure occur frequently. These severe conditions result from an overwhelming inflammatory response, induced by pathogen and damage associated molecular patterns (PAMPs and DAMPs) released into the bloodstream. In the present study, we demonstrated that the synthetic Lipopolysaccharid (LPS)-binding peptide 19-2.5 interferes with the activation of the coagulation and contact system. Moreover, binding of LPS to high molecular weight kininogen (HK), one of the major LPS carrier in blood, could be prevented by the peptide. Thus, peptide 19-2.5 might represent a promising target in the treatment of endotoxemia and sepsis, not only by its antiinflammatory potential, but also by the anticoagulant effect, together with its ability to prevent degradation of HK.Sepsis and septic shock are complications of bacterial infections that are associated with high mortality rates, despite the availability of antibiotics and improved intensive care. Complications from these life-threatening infections often arise when the initial appropriate host response to the invading pathogen is excessively amplified and progressively uncontrolled. A systemic activation of proteolytic host cascades, such as the coagulation and contact systems, together with a massive release of proinflammatory cytokines, can be deleterious for the host 1 .The majority of sepsis complications is caused by a disproportionate immune response to bacterial products, mainly lipopolysaccharide (LPS) in case of Gram-negative bacteria. LPS is localized in the outer layer of the membrane and is exposed on the bacterial surface. LPS contributes to the integrity of the outer membrane and protects the bacterium against the action of bile salts and lipophilic antibiotics. In sepsis, LPS can be released continuously due to cell growth and division, but also due to killed bacteria after an antibiotic treatment 2 .Free LPS is one of the most potent immune-stimulatory molecules, it can provoke a vigorous systemic inflammatory response and even minute doses may have lethal consequences for the host 3 . The response of host immune cells to LPS is initiated by its interaction with plasma proteins such as LPS-binding protein (LBP) and the specific receptor binding protein CD14 (soluble or membrane-bound), which finally leads to cell activation through the Toll-like receptor 4 (TLR4) 4 . Additionally, the plasma protein high molecular weight kininogen (HK) has been recently described to bind LPS and trigger inflammatory reactions. This might play a critical role for the LPS induced inflammatory response, as mice lacking HK, were resistant to LPS-induced mortality 5 . HK is mainly a cofactor of the human contact system, which consists of the serine proteases factor XI (FXI), factor XII (FXII), and plasma kallikrein (PK). HK circulates in a complex wi...

Procoagulant Activity of Blood and Microvesicles Is Disturbed by Pneumococcal Pneumolysin, Which Interacts with Coagulation Factors

“…It has been shown that the induction of procoagulant activity in blood or PBMCs by LPS and other PAMPs is associated with the release of pro- and anti-inflammatory cytokines [27, 37, 38]. We therefore measured IL-6, IL-10, and TNFα in the supernatant of PBMCs, treated with pneumolysin or autolysin.…”

“…PBMCs were isolated using diluted blood (1:1 in PBS) from healthy volunteers as described [27]. The PBMC cell layer was collected, and cells were washed twice in PBS and resuspended in RPMI medium (Invitrogen).…”

“…Thus, at sublytic concentrations pneumolysin did not accelerate PBMC-induced clot formation significantly, and if lytic concentrations were used (from 0.25 μg/mL), initiation of coagulation by PBMCs was significantly delayed due to cell lysis. associated with the release of pro-and anti-inflammatory cytokines [27,37,38]. We therefore measured IL-6, IL-10, and TNFα in the supernatant of PBMCs, treated with pneumolysin or autolysin.…”

PAMPs and DAMPs in Sepsis: A Review of Their Molecular Features and Potential Clinical Implications

“…Therefore, it has been proposed to search for well-conserved parts of the endotoxin, and a promising candidate could be part of the inner core region called 3-deoxy-D-manno-octulosonic acid (KDO) [45], or the lipid A with fully synthetic disaccharide lipid A mimetics (DLAMs) [46]. Among these peptides, we report, as an example, the LPS-binding peptide 19-2.5, which not only interferes with the activation of the coagulation and contact system but also prevent the interaction of LPS with the high molecular weight kininogen (HK), one of the major LPS carriers in blood [200].…”

Oriented immobilization of Pep19-2.5 on antifouling brushes suppresses the development of Staphylococcus aureus biofilms

“…Furthermore, it demonstrates very low cytotoxicity and can reduce the level of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) [64] as well as to attenuate cardiomyopathy in the septic heart [65,66]. Lately, it has been reported that this peptide also inhibits activation of the intrinsic coagulation pathway by significantly reducing the activity of Factor XI [67]. Recently, the high binding affinity of Pep19-2.5 towards Gram-positive and Gram-negative bacteria was explored for capturing bacteria in liquid samples [68].…”