Use of deuterium labeling by high‐temperature solid‐state hydrogen‐exchange reaction for mass spectrometric analysis of bradykinin biotransformation

Bolais-Ramos

et al. 2021

Preprint

Background and purpose: Bradykinin [BK-(1-9)] is an endogenous nonapeptide involved in multiple physiological and pathological processes. A long-held belief is that peptide fragments of BK-(1-9) are biologically inactive. Here, we have tested the biological activities of BK-(1-9) and two major peptide fragments in human and animal systems. Experimental Approach: Levels of BK peptides in male Wistar rat plasma were quantified by mass spectrometric methods. Nitric oxide was quantified in human, mouse and rat cells, and loaded with DAF-FM. We used aortic rings from adult male Wistar rats to test vascular reactivity. Changes in blood pressure and heart rate were measured in conscious adult male Wistar rats. Key results: Plasma levels of BK-(1-7) and BK-(1-5) in rats were increased following infusion of BK-(1-9). All tested peptides induced NO production in all cell types tested. However, unlike BK-(1-9), NO production elicited by BK-(1-7) or BK-(1-5) was not inhibited by B or B receptor antagonists. BK-(1-7) or BK-(1-5) also induced concentration-dependent vasorelaxation of aortic rings, without involving B or B receptors. In vivo, either intravenous or intra-arterial administration of BK-(1-7) or BK-(1-5) induced similar hypotension response. Conclusions and implications: BK-(1-7) and BK-(1-5) are endogenous peptides present in plasma. They are formed, at least partially, through the BK-(1-9) proteolysis. BK-related peptide fragments show biological activity, not mediated by B or B receptors. These BK-fragments could constitute new, active components of the kallikrein-kinin system.

Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Peptide fragments of bradykinin show unexpected biological activity not mediated by B1 or B2 receptors

Souza-Silva

Bolais-Ramos

et al. 2021

Preprint

“…However, we would like to stress that BK-(1-8), BK-(1-7) and BK-(1-5) have been identified as the major BK-(1-9) proteolytic fragments (2,19,23,27,31,41). Given the natural occurrence of these peptides and their biological activity reported in this manuscript, it is likely that BK-(1-7) and BK-(1-5) play important roles in physiological and pathological conditions, which requires extensive research to unravel their particularities.…”

Section: Discussionmentioning

confidence: 99%

“…However, all studies concluded that the fragments derived from BK-(1-9) were devoid of biological activity, except for BK-(1-8) (30, [32][33][34]44). From extensive studies regarding BK-(1-9) proteolysis, it is consensus that BK-(1-8), BK-(1-7) and BK-(1-5) are the major proteolytic fragments, being the latter the most stable fragment in plasma (19,41).…”

Section: Introductionmentioning

confidence: 99%

The kallikrein-kinin system is falling into pieces: bradykinin fragments are biological active peptides

Silva

Santos

et al. 2020

Preprint

Background and purpose: Bradykinin [BK-(1-9)] is an endogenous peptide involved in many physiological and pathological processes, such as cardiovascular homeostasis and inflammation. The central dogma of the kallikrein-kinin system is that BK-(1-9) fragments are biologically inactive. In this manuscript, we proposed to test whether these fragments were indeed inactive. Experimental Approach: Nitric oxide (NO) was quantified in human, mouse and rat cells loaded with DAF-FM after stimulation with BK-(1-9), BK-(1-7), BK-(1-5) and BK-(1-3). We used adult male rat aortic ring preparation to test vascular reactivity mediated by BK-(1-9) fragments. Changes in blood pressure and heart rate was measured in conscious adult male rats by intraarterial catheter method. Key results: BK-(1-9) induced NO production in all cell types tested by B2 receptor activation. BK-(1-7), BK-(1-5) and BK-(1-3) also induced NO production in all tested cell types but this response was independent of the activation of B1 receptor and/or B2 receptor. BK-(1-7), BK-(1-5) or BK-(1-3) induced only vasorelaxant effect and in a concentration-dependent fashion. Vasorelaxant effects for BK-(1-7), BK-(1-5) or BK-(1-3) were independent of the kinin receptors. Different administration routes (i.e., intravenous or intra-arterial) did not affect the observed hypotension induced by BK-(1-7), BK-(1-5) or BK-(1-3). Importantly, these observations diverged from the BK-(1-9) results, highlighting that indeed the BK-(1-9) fragments do not seem to act via the classical kinin receptors. Conclusions and implications: In conclusion, BK-(1-7), BK-(1-5) and BK-(1-3) are biologically active components of the kallikrein-kinin system. Importantly, observed pathophysiological outcomes of these peptides are independent of B1R and/or B2R activation.

“…neutral endopeptidase, now neprilysin), thus generating many different cleavage products (Campbell, 2013;Verano-Braga et al, 2020). A general conclusion of BK-(1-9) metabolism is that its major proteolytic fragment is BK-(1-8), which is acknowledged as the only biologically active BK peptide known to date, together with BK-(1-7) and BK-(1-5) that are regarded as biologically inert fragments (Kopylov et al, 2016;Semis et al, 2019). Thus, we present here a re-evaluation of the biological activities exhibited by BK-(1-7) and BK-(1-5), compared with those of the parent nonapeptide BK-(1-9), in a range of in vitro, ex vivo and in vivo systems, using human and rodent models.…”

Section: Introductionmentioning

confidence: 99%

Peptide fragments of bradykinin show unexpected biological activity not mediated by B₁ or B₂ receptors

Souza‐Silva

Bolais-Ramos

et al. 2022

British J Pharmacology

Background and Purpose Bradykinin (BK‐(1–9)) is an endogenous nonapeptide involved in multiple physiological and pathological processes. Peptide fragments of bradykinin are believed to be biologically inactive. We have now tested the two major peptide fragments of bradykinin in human and animals. Experimental Approach BK peptides were quantified by MS in male rats. NO release was quantified from human, mouse and rat cells loaded with DAF‐FM. Rat aortic rings were used to measure vascular reactivity. Changes in BP and HR were measured in conscious male rats. To evaluate pro‐inflammatory effects both vascular permeability and nociception were measured in adult mice. Key Results BK‐(1–7) and BK‐(1–5) are produced in vivo from BK‐(1–9). Both peptides induced NO production in all cell types tested. However, unlike BK‐(1–9), NO production elicited by BK‐(1–7) or BK‐(1–5) was not inhibited by B1 or B2 receptor antagonists. BK‐(1–7) and BK‐(1–5) induced concentration‐dependent vasorelaxation of aortic rings, without involvement of B1 or B2 receptors. Intravenous or intra‐arterial administration of BK‐(1–7) or BK‐(1–5) induced similar hypotensive response in vivo. Nociceptive responses of BK‐(1–7) and BK‐(1–5) were reduced compared to BK‐(1–9), and no increase in vascular permeability was observed for BK‐(1–9) fragments. Conclusions and Implications BK‐(1–7) and BK‐(1–5) are endogenous peptides present in plasma. BK‐related peptide fragments show biological activity, not mediated by B1 or B2 receptors. These BK fragments could constitute new, active components of the kallikrein–kinin system.