Extended cleavage specificity of the mast cell chymase from the crab-eating macaque (Macaca fascicularis): an interesting animal model for the analysis of the function of the human mast cell chymase

Abstract

Serine proteases are the major protein constituents within mast cell secretory granules. These proteases are subdivided into chymases and tryptases depending on their primary cleavage specificity. Here, we present the extended cleavage specificity of the macaque mast cell chymase and compare the specificity with human chymase (HC) and dog chymase (DC) that were produced in the same insect cell expression host. The macaque chymase (MC) shows almost identical characteristics as the HC, including both primary and extended cleavage specificities as well as sensitivity to protease inhibitors, whereas the DC differs in several of these characteristics. Although previous studies have shown that mouse mast cell protease-4 (mMCP-4) is similar in its hydrolytic specificity to the HC, mouse mast cells contain several related enzymes. Thus mice may not be the most appropriate model organism for studying HC activity and inhibition. Importantly, macaques express only one chymase and, as primates, are closely related to human general physiology. In addition, the human and macaque enzymes both cleave angiotensin I (Ang I) in the same way, generating primarily angiotensin II (Ang II) and they do not further degrade the peptide like most rodent enzymes do. Both enzymes also cleave two additional potential in vivo substrates, fibronectin and secretory leukocyte protease inhibitor (SLPI) in a similar way. Given the fact that both HC and MC are encoded by a single gene with high sequence homology and that many physiological processes are similar between these species, the macaque may be a very interesting model to study the physiological role of the chymase and to determine the potency and potential side-effects of various chymase inhibitors designed for therapeutic human use.

Highly Selective Cleavage of Cytokines and Chemokines by the Human Mast Cell Chymase and Neutrophil Cathepsin G

“…In addition, macaques have only one chymase in their chymase locus. For these reasons, with the exception of the ethical concerns, macaques seem to be an excellent animal model to study the biology of HC (37). In addition and interestingly, the almost complete absence of cleavage of any of the chemokines analyzed in this study indicates that these two enzymes have no or a lesser role in controlling chemokine activity in vivo.…”

“…Of the noncytokine chemokine targets identified for these enzymes, some are relatively well conserved, whereas others are cleaved only in primates (e.g., cleavage of secretory leukocyte protease inhibitor, which is cleaved by HC and macaque chymase but not by dog chymase) (37). In contrast, fibronectin and angiotensin I seem to be common targets for the chymases of many mammals (37). Recently, it also was shown that mMCP-4 degrades IGF-1, leading to adverse effects in cardiac remodeling after infarction (25).…”

Alpha-1 Antitrypsin, a Diagnostic and Prognostic Marker of Vernal Keratoconjunctivitis

“…Since, chymase is kept in control by AAT [21], it is quite possible that overexpression of chymase triggers the up-regulation of AAT in VKC patients. Chymase converts angiotensin-I to angiotensin-II [22] and also activates some endogenous peptides like endothelin, stem cell factor and interleukin-1β (IL-1β) [23], IL-1, IL-6, TNF-α and lipopolysaccharides have shown to up-regulate the synthesis of AAT [24]. IL-1 may therefore account for the increased antitryptic activity in the serum of VKC patients.…”

Extended Cleavage Specificities of Two Mast Cell Chymase-Related Proteases and One Granzyme B-Like Protease from the Platypus, a Monotreme

“…As neither chromogenic substrates nor phage display resulted in any information concerning the extended specificities of these three platypus enzymes, we instead tried a third alternative; to use a new type of recombinant substrate. A panel of such substrates has previously been designed and produced for the verification of the extended cleavage specificity following phage display analysis for a number of previously analysed mammalian hematopoietic and coagulation serine proteases [17,[21][22][23][24][25][26][27][28][29][30].…”