Characterization of Genes Encoding Known and Novel Human Mast Cell Tryptases on Chromosome 16p13.3

Pallaoro, Michele; Fejzo, Marlena S.; Shayesteh, Laleh; Blount, John L.; Caughey, George H.

doi:10.1074/jbc.274.6.3355

Cited by 131 publications

(182 citation statements)

References 36 publications

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“…They are 95-99% identical and are encoded by 2 adjacent genes on human chromosome 16p13.3 (20). Their murine equivalents are mouse MC protease 6 (mMCP-6) (21) and mMCP-7 (22).…”

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confidence: 99%

The mouse mast cell–restricted tetramer‐forming tryptases mouse mast cell protease 6 and mouse mast cell protease 7 are critical mediators in inflammatory arthritis

McNeil

Shin

Campbell

et al. 2008

Arthritis & Rheumatism

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Objective. Increased numbers of mast cells (MCs) that express ␤ tryptases bound to heparin have been detected in the synovium of patients with rheumatoid arthritis (RA). The corresponding tryptases in mice are mouse MC protease 6 (mMCP-6) and mMCP-7. Although MCs have been implicated in RA and some animal models of arthritis, no direct evidence for a MC-restricted tryptase in the pathogenesis of inflammatory arthritis has been shown. We created transgenic mice that lack heparin and different combinations of mMCP-6 and mMCP-7, to evaluate the roles of MCrestricted tryptase-heparin complexes in an experimental model of arthritis.Methods. The methylated bovine serum albumin/ interleukin-1␤ (mBSA/IL-1␤) experimental protocol was used to induce inflammatory monarthritis in different mouse strains. Mice were killed at the time of peak disease on day 7, and histochemical methods were used to assess joint pathology.Results. Arthritis was induced in the knee joints of mBSA/IL-1␤-treated mMCP-6 ؉ /mMCP-7 ؊ and mMCP-6 ؊ /mMCP-7 ؉ C57BL/6 mice, and numerous activated MCs that had exocytosed the contents of their secretory granules were observed in the diseased mice. In contrast, arthritis was markedly reduced in heparindeficient mice and in mMCP-6 ؊ /mMCP-7 ؊ C57BL/6 mice.Conclusion. MC-derived tryptase-heparin complexes play important roles in mBSA/IL-1␤-induced arthritis. Because mMCP-6 and mMCP-7 can compensate for each other in this disease model, the elimination of both tryptases is necessary to reveal the prominent roles of these serine proteases in joint inflammation and destruction. Our data suggest that the inhibition of MC-restricted tryptases could have therapeutic potential in the treatment of RA.Rheumatoid arthritis (RA) is an inflammatory disorder of synovial joints characterized by damage to articular structures due to chronic inflammation of the synovium. Numerous cellular participants of innate and adaptive immunity contribute to the pronounced inflammatory processes seen in rheumatoid synovitis. Our group (1-4) and many other investigators (5-14) have obtained data implicating a prominent involvement of mast cells (MCs) and their mediators in RA and some animal models of this autoimmune disorder. On a weight basis, tetramer-forming ␤ tryptases (15)(16)(17)(18)(19) are the most abundant proteins present in the secretory granules of human MCs. Three ␤ tryptase complementary DNAs (designated hTryptase ␤1, ␤2, and ␤3) have been cloned.

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“…They are 95-99% identical and are encoded by 2 adjacent genes on human chromosome 16p13.3 (20). Their murine equivalents are mouse MC protease 6 (mMCP-6) (21) and mMCP-7 (22).…”

mentioning

confidence: 99%

The mouse mast cell–restricted tetramer‐forming tryptases mouse mast cell protease 6 and mouse mast cell protease 7 are critical mediators in inflammatory arthritis

McNeil

Shin

Campbell

et al. 2008

Arthritis & Rheumatism

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“…All populations of MCs examined to date store in their secretory granules various combinations of carboxypeptidase A, chymases, and tryptases ionically bound to serglycin proteoglycans that contain either heparin or highly sulfated chondroitin glycosaminoglycans. Human MCs express at least five distinct tryptases, and the cDNAs and genes have been isolated that encode human tryptases ␣, ␤I, ␤II, and ␤III, as well as a less homologous transmembrane tryptase (5)(6)(7)(8)(9)(10). Mapping and sequencing analysis of the region of human chromosome 16, where these genes reside, has revealed the presence of additional genes in the family (9,11), but it remains to be determined whether or not any of these genes encode enzymatically active proteases.…”

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confidence: 99%

Evaluation of the Substrate Specificity of Human Mast Cell Tryptase βI and Demonstration of Its Importance in Bacterial Infections of the Lung

Huang¹,

Sanctis²,

O’Brien³

et al. 2001

Journal of Biological Chemistry

139

132

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Human pulmonary mast cells (MCs) express tryptases ␣ and ␤I, and both granule serine proteases are exocytosed during inflammatory events. Recombinant forms of these tryptases were generated for the first time to evaluate their substrate specificities at the biochemical level and then to address their physiologic roles in pulmonary inflammation. Analysis of a tryptase-specific, phage display peptide library revealed that tryptase ␤I prefers to cleave peptides with 1 or more Pro residues flanked by 2 positively charged residues. Although recombinant tryptase ␤I was unable to activate cultured cells that express different types of protease-activated receptors, the numbers of neutrophils increased >100-fold when enzymatically active tryptase ␤I was instilled into the lungs of mice. In contrast, the numbers of lymphocytes and eosinophils in the airspaces did not change significantly. More important, the tryptase ␤I-treated mice exhibited normal airway responsiveness. Neutrophils did not extravasate into the lungs of tryptase ␣-treated mice. Thus, this is the first study to demonstrate that the two nearly identical human MC tryptases are functionally distinct in vivo. When MCdeficient W/W v mice were given enzymatically active tryptase ␤I or its inactive zymogen before pulmonary infection with Klebsiella pneumoniae, tryptase ␤I-treated W/W v mice had fewer viable bacteria in their lungs relative to zymogen-treated W/W v mice. Because neutrophils are required to combat bacterial infections, human tryptase ␤I plays a critical role in the antibacterial host defenses of the lung by recruiting neutrophils in a manner that does not alter airway reactivity.

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“…Several in vitro studies have identified multiple substrates for tryptase, including neuropeptides, fibrinogen, stromelysin, prourokinase, prothrombin, and protease-activated receptor-2 (3-6). Human chromosome 16 encodes several homologous tryptase genes, designated tryptase ␣, ␤, and ␥ (7,8). The ␤-tryptases share greater than 99% sequence identity, with tryptase ␤I and ␤II differing by a single N-glycosylation site.…”

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confidence: 99%

Definition of the Extended Substrate Specificity Determinants for β-Tryptases I and II

Harris¹,

Niles²,

Burdick³

et al. 2001

Journal of Biological Chemistry

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Tryptases ␤I and ␤II were heterologously expressed and purified in yeast to functionally characterize the substrate specificity of each enzyme. Three positional scanning combinatorial tetrapeptide substrate libraries were used to determine the primary and extended substrate specificity of the proteases. Both enzymes have a strict primary preference for cleavage after the basic amino acids, lysine and arginine, with only a slight preference for lysine over arginine. ␤I and ␤II tryptase share similar extended substrate specificity, with preference for proline at P4, preference for arginine or lysine at P3, and P2 showing a slight preference for asparagine. Measurement of kinetic constants with multiple substrates designed for ␤-tryptases reveal that selectivity is highly dependent on ground state substrate binding. Coupled with the functional determinants, structural determinants of tryptase substrate specificity were identified. Molecular docking of the preferred substrate sequence to the three-dimensional tetrameric tryptase structure reveals a novel extended substrate binding mode that involves interactions from two adjacent protomers, including P4 Thr-96, P3 Asp-60B and Glu-217, and P1 Asp-189. Based on the determined substrate information, a mechanism-based tetrapeptide-chloromethylketone inhibitor was designed and shown to be a potent tryptase inhibitor. Finally, the cleavage sites of several physiologically relevant substrates of ␤-tryptases show consistency with the specificity data presented here.Mast cells, mediators of inflammatory and allergic response, are found throughout the body concentrated near blood vessels in connective tissue and the mucous membranes of the respiratory and gastrointestinal tract. They play an important role in innate and acquired immune responses through the release of dense granules upon activation. Mast cell activation has also been implicated as a mediator of asthma and other inflammatory diseases. The major components of mast cell secretory granules are the tryptase serine proteases (1). Tryptases are secreted as catalytically active tetramers that are resistant to inactivation by plasma inhibitors. The 3-Å crystal structure has been solved and reveals a ringlike structure with the four active sites facing a central cavity (2). Several in vitro studies have identified multiple substrates for tryptase, including neuropeptides, fibrinogen, stromelysin, prourokinase, prothrombin, and protease-activated receptor-2 (3-6). Human chromosome 16 encodes several homologous tryptase genes, designated tryptase ␣, ␤, and ␥ (7, 8). The ␤-tryptases share greater than 99% sequence identity, with tryptase ␤I and ␤II differing by a single N-glycosylation site. It is unclear why so many highly similar tryptases are expressed by mast cells. One possibility is that they each perform different proteolytic functions that may be reflected in their substrate specificity preferences. Indeed, it has recently been shown that a single amino acid substitution between tryptase ␣ and tryptase ␤II account...

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Characterization of Genes Encoding Known and Novel Human Mast Cell Tryptases on Chromosome 16p13.3

Cited by 131 publications

References 36 publications

The mouse mast cell–restricted tetramer‐forming tryptases mouse mast cell protease 6 and mouse mast cell protease 7 are critical mediators in inflammatory arthritis

The mouse mast cell–restricted tetramer‐forming tryptases mouse mast cell protease 6 and mouse mast cell protease 7 are critical mediators in inflammatory arthritis

Evaluation of the Substrate Specificity of Human Mast Cell Tryptase βI and Demonstration of Its Importance in Bacterial Infections of the Lung

Definition of the Extended Substrate Specificity Determinants for β-Tryptases I and II

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