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Shinsuke Yasuda

Publications and source records attributed to Shinsuke Yasuda.

At least 19 recordsLinked to original sources
PubMed2024

Muscle Tissue Transcriptome of Idiopathic Inflammatory Myopathy Reflects the Muscle Damage Process by Monocytes and Presence of Skin Lesions.

OBJECTIVE: We aim to investigate transcriptomic and immunophenotypic features of muscle specimens from patients with idiopathic inflammatory myopathy (IIM). METHODS: Bulk RNA-sequencing was performed on muscle biopsy samples from 16 patients with dermatomyositis (DM) and 9 patients with polymyositis (PM). Seven tested positive for anti-aminoacyl transfer RNA synthetase antibodies in the patients with DM (ARS-DM). We conducted weighted gene coexpression network analysis (WGCNA), differentially expressed gene (DEG) analysis, and gene set variation analysis to assess contributions of specific pathways. Cell proportions in muscle specimens were estimated using a deconvolution approach. RESULTS: WGCNA revealed significant positive correlations between serum creatine kinase (CK) levels and gene modules involved in cellular respiration, phagocytosis, and oxidative phosphorylation (OXPHOS). Significant positive correlations were also observed between CK levels and proportions of CD16-positive and negative monocytes and myeloid dendritic cells. Notably, patients with DM demonstrated enrichment of complement and interferon-α and γ pathway genes compared with those with PM. Furthermore, ARS-DM demonstrated a higher proportion of Th1 cells and DEGs related to OXPHOS. Additionally, serum Krebs von den Lungen-6 levels correlated with gene modules associated with extracellular matrix and the transforming growth factor-β signaling pathway. CONCLUSION: Our study highlights a significant involvement of monocytes in muscle damage and delineates pathologic differences among IIM subtypes. DM was characterized by complement and interferon-α and γ signaling, whereas ARS-DM was associated with OXPHOS. Distinctive gene expression variations in muscle specimens suggest that different pathologic mechanisms underlie muscle damage in each IIM phenotype.

Humans↗
PubMed2006

[New insights into the pathogenicity of antiphospholipid antibodies].

Antiphospholipid antibodies (aPL) recognize phospholipid-binding proteins such as beta(2)-glycoprotein I (beta(2)-GPI) and prothrombin, inducing thrombosis and pregnancy morbidities. Pathogenicity of aPL has been established by many in vivo experiments in which administration of aPL resulted in pregnancy losses and/or thrombotic phenomena. The mechanisms how aPL cause such symptoms have been extensively investigated. aPL alters fibrinolysis/coagulation system by suppression of protein C/Z systems in the presence of beta(2)-GPI. B cell epitopes were also studied for specific therapies, resulting in diverse candidates such as domain I, IV or other domains. For T cells, importance of cryptic epitope on domain V was suggested. Recently, activation of endothelial cells, monocytes and thrombocytes by aPL with beta(2)-GPI has been reported. This activation is mainly mediated by p38MAP kinase activation and results in expression of tissue factor and adhesion molecules in endothelial cells and monocytes, thromboxane B2 in thrombocytes. Annexin II, toll-like receptor 4, LDL-receptor family members, and glycoprotein Ib are the candidates for cell surface ligands, suggesting the possibility of their blockades by monoclonal antibodies. Although treatment of APS is now limited to nonspecific anticoagulants or anti-platelet agents, based on these new insights, specific therapies targeting signal molecules and/or cell surface ligands for beta(2)-GPI should be introduced in near future.

Animals↗
PubMed2005

Pathogenesis of antiphospholipid antibodies: impairment of fibrinolysis and monocyte activation via the p38 mitogen-activated protein kinase pathway.

Antiphospholipid syndrome (APS) is characterized by recurrent thrombosis or pregnancy morbidity associated with antiphospholipid antibodies (aPL). Impaired fibrinolysis is a contributing factor for the development of thrombosis, and the effect of aPL in the fibrinolytic system has been investigated. Impaired release of tPA and enhanced release of PAI-1 after endothelial activation is reported in patients with APS. Elevated Lipoprotein (a) levels have been found in APS, which results in inhibition of fibrinolytic activity. Phospholipid-bound beta(2)-glycoprotein I (beta(2)GPI) is a major autoantigen for aPLs. beta(2)GPI exerts both anti-coagulant and pro-coagulant properties mainly by interacting with other phospholipid-binding proteins such as coagulation factors and protein C. Dramatic increase in the affinity of beta(2)GPI to the cell surface is induced by binding of pathogenic anti-beta(2)GPI antibodies, which may modify the physiological function of beta(2)GPI and may affect the coagulation/fibrinolysis balance on the cell surface. Using chromogenic assays for measuring fibrinolytic activity, we demonstrated that addition of monoclonal anticardiolipin antibody (aCL) decreases the activity of extrinsic/intrinsic fibrinolysis. Significantly lower activity of intrinsic fibrinolysis was also demonstrated in the euglobulin fractions from APS patients. Endothelial cells and monocytes are activated by aPLs in vitro, resulting in production of tissue factor (TF), a major initiator of the coagulation system. Recently, aPLs are reported to induce thrombocytes to produce thromboxane. The importance of apoE receptor 2 on platelets for the binding of artificially dimerized beta(2)GPI was suggested. By investigating aPL-inducible genes in peripheral blood mononuclear cells, we found that the mitogen-activated protein kinase (MAPK) pathway was up-regulated. Using a monocyte cell line, phosphorylation of p38 MAPK, NF-kappaB translocation to the nuclear fraction, and up-regulated TF mRNA expression were demonstrated after treatment with monoclonal aCL. These phenomena were observed only in the presence of beta(2)GPI. Moreover, a specific p38 MAPK inihibitor SB203580 decreased aCL/beta(2)GPI-induced TF mRNA expression. Thus, aCL/beta(2)GPI plays dual roles in the pathogenesis of APS, firstly by deranging the fibrinolytic system and secondly by activating monocytes, endothelial cells and thrombocytes to produce TF or thromboxane.

Antibodies, Antiphospholipid↗
PubMed2005

Antigenic structures recognized by anti-beta2-glycoprotein I auto-antibodies.

Beta2-glycoprotein I (beta2-GPI) is a major antigen for anti-cardiolipin antibodies and their epitopes are cryptic. Conformation of each domain of beta2-GPI was optimized from its crystal structure by energy minimization and by molecular dynamics simulation. Three electrostatic interactions, i.e. D193-K246, D222-K317 and E228-K308, were observed between domains IV and V in the optimized structure that was constructed based on the consensus sequences obtained by the phage-displayed random peptide library. Antigenic structures determined by the epitope mapping mainly consisted of hydrophobic amino acids located on two discontinuous sequences in domain IV. These amino acid clusters, as an epitope, were covered by domain V and were of a hidden nature. A similar but incomplete counterpart to the epitopic clusters was found in domain I but was not in domains II or III. Binding of anti-beta2-GPI auto-antibodies to solid-phase beta2-GPI was significantly reduced either by L replacement for W235, a common amino acid component for the epitopes, or by V replacement for all of D193, D222 and E228. Structural analysis indicated a hypothesis that these electrostatic interactions between domains IV and V retained exposure to W235 and that epitope spreading occurred in the region surrounding W235. Thus, epitopic structures recognized by anti-beta2-GPI auto-antibodies are cryptic and inter-domain electrostatic interactions are involved in their in exposure.

Amino Acid Substitution↗
PubMed2005

Mast cell protease 5 mediates ischemia-reperfusion injury of mouse skeletal muscle.

Ischemia with subsequent reperfusion (IR) injury is a significant clinical problem that occurs after physical and surgical trauma, myocardial infarction, and organ transplantation. IR injury of mouse skeletal muscle depends on the presence of both natural IgM and an intact C pathway. Disruption of the skeletal muscle architecture and permeability also requires mast cell (MC) participation, as revealed by the fact that IR injury is markedly reduced in c-kit defective, MC-deficient mouse strains. In this study, we sought to identify the pathobiologic MC products expressed in IR injury using transgenic mouse strains with normal MC development, except for the lack of a particular MC-derived mediator. Histologic analysis of skeletal muscle from BALB/c and C57BL/6 mice revealed a strong positive correlation (R(2) = 0.85) between the extent of IR injury and the level of MC degranulation. Linkage between C activation and MC degranulation was demonstrated in mice lacking C4, in which only limited MC degranulation and muscle injury were apparent. No reduction in injury was observed in transgenic mice lacking leukotriene C(4) synthase, hemopoietic PGD(2) synthase, N-deacetylase/N-sulfotransferase-2 (enzyme involved in heparin biosynthesis), or mouse MC protease (mMCP) 1. In contrast, muscle injury was significantly attenuated in mMCP-5-null mice. The MCs that reside in skeletal muscle contain abundant amounts of mMCP-5 which is the serine protease that is most similar in sequence to human MC chymase. We now report a cytotoxic activity associated with a MC-specific protease and demonstrate that mMCP-5 is critical for irreversible IR injury of skeletal muscle.

Animals↗
PubMed2005

Urokinase-type plasminogen activator is a preferred substrate of the human epithelium serine protease tryptase epsilon/PRSS22.

Tryptase epsilon is a member of the chromosome 16p13.3 family of human serine proteases that is preferentially expressed by epithelial cells. Recombinant pro-tryptase epsilon was generated to understand how the exocytosed zymogen might be activated outside of the epithelial cell, as well as to address its possible role in normal and diseased states. Using expression/site-directed mutagenesis approaches, we now show that Lys20, Cys90, and Asp92 in the protease's substrate-binding cleft regulate its enzymatic activity. We also show that Arg(-1) in the propeptide domain controls its ability to autoactivate. In vitro studies revealed that recombinant tryptase epsilon possesses a restricted substrate specificity. Once activated, tryptase epsilon cannot be inhibited effectively by the diverse array of protease inhibitors present in normal human plasma. Moreover, this epithelium protease is not highly susceptible to alpha1-antitrypsin or secretory leukocyte protease inhibitor, which are present in the lung. Recombinant tryptase epsilon could not cleave fibronectin, vitronectin, laminin, single-chain tissue-type plasminogen activator, plasminogen, or any prominent serum protein. Nevertheless, tryptase epsilon readily converted single-chain pro-urokinase-type plasminogen activator (pro-uPA/scuPA) into its mature, enzymatically active protease. Tryptase epsilon also was able to induce pro-uPA-expressing smooth muscle cells to increase their migration through a basement membrane-like extracellular matrix. The ability to activate uPA in the presence of varied protease inhibitors suggests that tryptase epsilon plays a prominent role in fibrinolysis and other uPA-dependent reactions in the lung.

Animals↗
PubMed2005

Significance of valine/leucine247 polymorphism of beta2-glycoprotein I in antiphospholipid syndrome: increased reactivity of anti-beta2-glycoprotein I autoantibodies to the valine247 beta2-glycoprotein I variant.

OBJECTIVE: To clarify the consequences of the valine/leucine polymorphism at position 247 of the beta(2)-glycoprotein I (beta(2)GPI) gene in patients with antiphospholipid syndrome (APS), by investigating the correlation between genotypes and the presence of anti-beta(2)GPI antibody. The reactivity of anti-beta(2)GPI antibodies was characterized using recombinant Val(247) and Leu(247) beta(2)GPI. METHODS: Sixty-five Japanese patients with APS and/or systemic lupus erythematosus who were positive for antiphospholipid antibodies and 61 controls were analyzed for the presence of the Val/Leu(247) polymorphism of beta(2)GPI. Polymorphism assignment was determined by polymerase chain reaction followed by restriction enzyme digestion. Recombinant Val(247) and Leu(247) beta(2)GPI were established to compare the reactivity of anti-beta(2)GPI antibodies to beta(2)GPI between these variants. The variants were prepared on polyoxygenated plates or cardiolipin-coated plates, and the reactivity of a series of anti-beta(2)GPI antibodies (immunized anti-human beta(2)GPI monoclonal antibodies [Cof-19-21] and autoimmune anti-beta(2)GPI monoclonal antibodies [EY1C8, EY2C9, and TM1G2]) and IgGs purified from patient sera was investigated. RESULTS: A positive correlation between the Val(247) allele and the presence of anti-beta(2)GPI antibodies was observed in the patient group. Human monoclonal/polyclonal anti-beta(2)GPI autoantibodies showed higher binding to recombinant Val(247) beta(2)GPI than to Leu(247) beta(2)GPI, although no difference in the reactivity of the immunized anti-beta(2)GPI between these variants was observed. Conformational optimization showed that the replacement of Leu(247) by Val(247) led to a significant alteration in the tertiary structure of domain V and/or the domain IV-V interaction. CONCLUSION: The Val(247) beta(2)GPI allele was associated with both a high frequency of anti-beta(2)GPI antibodies and stronger reactivity with anti-beta(2)GPI antibodies compared with the Leu(247) beta(2)GPI allele, suggesting that the Val(247) beta(2)GPI allele may be one of the genetic risk factors for development of APS.

Adult↗
PubMed2005

Butyrate suppresses tumor necrosis factor alpha production by regulating specific messenger RNA degradation mediated through a cis-acting AU-rich element.

OBJECTIVE: To study the capacity of butyrate to inhibit production of tumor necrosis factor alpha (TNFalpha) in macrophage-like synoviocytes (MLS) from patients with rheumatoid arthritis (RA), in human peripheral monocytes, and in murine RAW264.7 macrophages. METHODS: The concentrations of TNFalpha in culture supernatants of these cells were measured using enzyme-linked immunosorbent assay. The expression levels of various messenger RNAs (mRNA), such as those for TNFalpha, the mRNA-binding protein TIS11B, and luciferase, were measured using real-time quantitative polymerase chain reaction. The in vitro effects of butyrate on transcriptional regulation were evaluated by transfection with various reporter plasmids in RAW264.7 macrophages. The effects of TIS11B on TNFalpha expression were examined using an overexpression model of TIS11B in RAW264.7 cells. RESULTS: Butyrate suppressed TNFalpha protein and mRNA production in MLS and monocytes, but paradoxically enhanced transactivation of the TNFalpha promoter. Expression of the AU-rich element (ARE)-binding protein TIS11B was up-regulated by butyrate. Induction of TNFalpha mRNA by lipopolysaccharide was significantly inhibited when TIS11B was overexpressed. Butyrate facilitated the degradation of luciferase transcripts containing the 3'-untranslated region (3'-UTR) of TNFalpha, and this effect was dependent on the ARE in the 3'-UTR that is known to be involved in the regulation of mRNA degradation. CONCLUSION: These results indicate that butyrate suppresses TNFalpha expression by facilitating mRNA degradation mediated through a cis-acting ARE. Butyrate has the ability to regulate TNFalpha at the mRNA level and is therefore a potential therapeutic drug for RA patients.

3' Untranslated Regions↗
PubMed2005

Research around beta 2-glycoprotein I: a major target for antiphospholipid antibodies.

Beta2-glycoprotein I (beta2GPI), a phospholipid-binding protein, is one of the major target antigens for antiphospholipid antibodies (aPL) found in patients with antiphospholipid syndrome (APS). Thrombophilic disorders in APS patients are strongly associated with aPL, and their pathogenic properties depend on the presence of beta2GPI. Procoagulant cell stimulation by aPL, via beta2GPI, is one of the most plausible mechanisms of thrombosis in APS, and p38 mitogen activated protein kinase (MAPK) pathway plays a crucial role in such activation. beta2GPI is proteolytically cleaved in domain V by activated factor X or plasmin, leading to the generation of the nicked form of beta2GPI. Recently, increasing attention is focused on the role of nicked-beta2GPI as a regulator of extrinsic fibrinolysis pathway.

Amino Acid Sequence↗
PubMed2004

The p38 mitogen-activated protein kinase (MAPK) pathway mediates induction of the tissue factor gene in monocytes stimulated with human monoclonal anti-beta2Glycoprotein I antibodies.

The anti-phospholipid syndrome (APS) is characterized by thrombosis and the presence of anti-phospholipid antibodies (aPL). Tissue factor (TF), the major initiator of the coagulation system, is induced on monocytes by aPL in vitro, explaining, in part, the pathophysiology in this syndrome. However, little is known regarding the nature of the aPL-induced signal transduction pathways leading to TF expression. In this study, we investigated aPL-inducible genes in PBMC using cDNA array system and real-time PCR. Our results indicated that the mitogen-activated protein kinase (MAPK) pathway was related to TF expression when PBMCs were treated, in the presence of beta(2)Glycoprotein I (beta(2)GPI), with human monoclonal anti-beta(2)GPI antibodies [beta(2)GPI-dependent anti-cardiolipin antibodies (aCL/beta(2)GPI)]. Western blotting studies using monocyte cell line (RAW264.7) demonstrated that p38 MAPK protein was phosphorylated with nuclear factor kappaB (NF-kappaB) activation by monoclonal aCL/beta(2)GPI treatment, and that SB203580, a specific p38 MAPK inhibitor, decreased the aCL/beta(2)GPI-induced TF mRNA expression. The p38 MAPK phosphorylation, NF-kappaB translocation and TF mRNA expression triggered by aCL/beta(2)GPI were abolished in the absence of beta(2)GPI. These results demonstrated that the p38 MAPK signaling pathway plays an important role in aPL-induced TF expression on monocytes and suggest that the p38 MAPK may be a possible therapeutic target to modify a pro-thrombotic state in patients with APS.

Antibodies, Monoclonal↗
PubMed2004

Nicked beta2-glycoprotein I: a marker of cerebral infarct and a novel role in the negative feedback pathway of extrinsic fibrinolysis.

BEta(2)-glycoprotein I (beta(2)-GPI) is proteolytically cleaved by plasmin in domain V (nicked beta(2)-GPI), being unable to bind to phospholipids. This cleavage may occur in vivo and elevated plasma levels of nicked beta(2)-GPI were detected in patients with massive plasmin generation and fibrinolysis turnover. In this study, we report higher prevalence of elevated ratio of nicked beta(2)-GPI against total beta(2)-GPI in patients with ischemic stroke (63%) and healthy subjects with lacunar infarct (27%) when compared to healthy subjects with normal findings on magnetic resonance imaging (8%), suggesting that nicked beta(2)-GPI might have a physiologic role beyond that of its parent molecule in patients with thrombosis. Several inhibitors of extrinsic fibrinolysis are known, but a negative feedback regulator has not been yet documented. We demonstrate that nicked beta(2)-GPI binds to Glu-plasminogen with K(D) of 0.37 x 10(-6) M, presumably mediated by the interaction between the fifth domain of nicked beta(2)-GPI and the fifth kringle domain of Glu-plasminogen. Nicked beta(2)-GPI also suppressed plasmin generation up to 70% in the presence of tissue plasminogen activator, plasminogen, and fibrin. Intact beta(2)-GPI lacks these properties. These data suggest that beta(2)-GPI/plasmin-nicked beta(2)-GPI controls extrinsic fibrinolysis via a negative feedback pathway loop.

Aged↗
PubMed2004

Abacterial prostatitis and primary biliary cirrhosis with SjOgren's syndrome.

In patients with SjOgren's syndrome (SS), the salivary and lacrimal glands are often affected, although other epithelial tissues can become inflamed. Here, we report the first case of abacterial prostatitis in a patient with SS complicated by primary biliary cirrhosis. Histologically, the distribution and subpopulation of infiltrating lymphocytes were similar in the salivary gland, liver, and prostate. Treatment with steroid was successful. We speculate that the prostate may be one of the target organs in SS.

Journal Article↗
PubMed2004

Beta2-glycoprotein I, anti-beta2-glycoprotein I, and fibrinolysis.

Beta2-glycoprotein-I (beta2GPI) is a phospholipid-binding plasma protein that consists of five homologous domains. Domain V is distinguished from others by bearing a positively charged lysine cluster and hydrophobic extra C-terminal loop. Beta2GPI has been known as a natural anticoagulant regulator. Beta2GPI exerts anticoagulant activity by inhibition of phospholipid-dependent coagulation reactions such as prothrombinase, tenase, and factor XII activation. It also binds factor XI and inhibits its activation. On the other hand, beta2GPI inhibits anticoagulant activity of activated protein C. According to the data from knockout mice, beta2GPI may contribute to thrombin generation in vivo. Phospholipid-bound beta2GPI is one of the major target antigens for antiphospholipid antibodies present in patients with antiphospholipid syndrome (APS). Binding of pathogenic anti-beta2GPI antibodies increases the affinity of beta2GPI to the cell surface and disrupts the coagulation/fibrinolysis balance on the cell surface. These pathogenic antibodies activate endothelial cells via signal transduction events in the presence of beta2GPI. Impaired fibrinolysis has been reported in patients with APS. Using a newly developed chromogenic assay, we demonstrated lower activity of intrinsic fibrinolysis in euglobulin fractions from APS patients. Addition of monoclonal anti-beta2GPI antibodies with beta2GPI also decreased fibrinolytic activity in this assay system. beta2GPI is proteolytically cleaved by plasmin in domain V (nicked beta2GPI) and becomes unable to bind to phospholipids, reducing antigenicity against antiphospholipid antibodies. This cleavage occurs in patients with increased fibrinolysis turnover. Nicked beta2GPI binds to plasminogen and suppresses plasmin generation in the presence of fibrin, plasminogen, and tissue plasminogen activator (tPA). Thus, nicked beta2GPI plays a role in the extrinsic fibrinolysis via a negative feedback pathway loop.

Animals↗
PubMed2004

Antiprothrombin antibodies--are they worth assaying?

According to the preliminary classification criteria of the antiphospholipid syndrome (APS) (Sapporo Criteria), beta2-glycoprotein I (beta2GPI)-dependent anticardiolipin antibodies (aCL) and lupus anticoagulant (LA) are the only laboratory tests considered as criteria for the classification of the APS. Recently, antibodies against phosphatidylserine-prothrombin complex (aPS/PT) have been detected and these antibodies, rather than antibodies against prothrombin alone, are closely associated with APS and LA. We assessed the sensitivity and specificity of aPS/PT for the diagnosis of APS in our population of patients with a variety of autoimmune disorders and investigated whether aPS/PT could be used as diagnostic test in patients suspected of having APS. The study population comprised 219 patients with autoimmune diseases including 82 patients with APS and 137 without APS (55 systemic lupus erythematosus, 32 rheumatoid arthritis, 10 primary Sjogren's syndrome, 8 scleroderma, 5 Behcet's disease and 27 other rheumatic diseases). IgG/M aPS/PT were measured by ELISA using phosphatidylserine-prothrombin complex as antigen immobilized on ELISA plates in the presence of CaCl2. IgG/M aCL were measured by standard methods and LA was detected by clotting assays. aPS/PT, aCL and LA were more frequently found in patients with APS (47, 46 and 69, respectively) than in those without APS (11, 19 and 29, respectively) (OR 95% [CI]; 15.4 [7.2-32.7], 7.9 [4.1-15.2, 19.8 [9.6-40.6], respectively]. The sensitivity of each assay for the diagnosis of APS was 57%, 56% and 86% with a specificity of 92%, 86% and 79%, respectively. aPS/PT and aCL have similar diagnostic value for APS, therefore, we propose that aPS/PT should be further explored, not only for research purposes, but also as a candidate of one of the laboratory criteria for the classification of the APS.

Antibodies, Antiphospholipid↗
PubMed2004

[Pathogenic roles of anti-beta2-GPI antibody in patients with antiphospholipid syndrome].

Antiphospholipid syndrome (APS) is characterized by arterial and/or venous thrombosis and pregnancy morbidity in the presence of antiphospholipid antibodies (aPL). Beta2-glycoprotein I (beta2-GPI) and prothrombin are representative autoantigens, the former more extensively investigated. Anti-beta2-GPI antibodies are not only markers of APS, but also are considered to be pathogenic. Possible roles of anti-beta2-GPI antibodies are, 1) enhancement the binding of beta2-GPI to anionic phospholipid and inhibition of protein C activation/activated protein C, 2) to form anti-beta2-GPI antibody-beta2-GPI-oxidized LDL complex and to promote uptake by sub-endothelial macrophage, resulting in atherosclerosis, 3) to dimerize beta2-GPI on the surface of platelets and to activate platelets via apoE receptor 2 and subsequent signal transduction, 4) stimulation of monocytes via p38 MAP kinase pathway and induction of tissue factor production. In pregnancy morbidity, activation of complement cascade plays an important role. These findings may provide a novel target in the management of APS.

Antiphospholipid Syndrome↗
PubMed2003

Mouse chromosome 17A3.3 contains 13 genes that encode functional tryptic-like serine proteases with distinct tissue and cell expression patterns.

Probing of the mouse EST data base at GenBank trade mark with known tryptase cDNAs resulted in the identification of undiscovered serine protease transcripts whose genes reside at a 1.5-Mb complex on mouse chromosome 17A3.3. Mouse tryptase-5 (mT5), tryptase-6 (mT6), and mast cell protease-11 (mMCP-11) are new members of this serine protease superfamily whose amino acid sequences are 36-54% identical to each other and to their other 10 family members. The 13 functional mouse proteases can be subdivided into two subgroups based on conserved features in their propeptides. Of the three new serine proteases, mT6 is most widely expressed in tissues. mT5 is preferentially expressed in smooth muscle, whereas mMCP-11 is preferentially expressed in the spleen and bone marrow. In contrast to mT5 and mT6, mMCP-11 is also expressed in mast cells. Although mT6 and mMCP-11 are constitutively secreted when expressed in mammalian and insect cells, mT5 remains membrane-associated. The fact that recombinant mT5, mT6, and mMCP-11 possess non-identical expression patterns and substrate specificities suggests that each protease has a unique function in vivo. Of the 13 functional mouse tryptase genes identified at the complex, 12 have orthologs that reside in the syntenic region of human chromosome 16p13.3. The establishment of these ortholog pairs helps clarify the evolutionary relationship of the serine protease locus in the two species. This information provides a useful framework for the functional analysis of each protease using gene targeting and other molecular approaches.

Amino Acid Sequence↗
PubMed2003

Mouse mast cells express the tryptic protease neuropsin/Prss19.

The only tryptic enzymes identified so far in mouse mast cells (MCs) are three members of the chromosome 17A3.3 family of neutral proteases. Sequence analysis of a cDNA library revealed that BALB/c mouse bone marrow-derived MCs express neuropsin, a member of the chromosome 7B2 family of tryptic kallikreins. Kinetic studies revealed that neuropsin is expressed relatively early in MC development. As assessed immunohistochemically, the MCs residing in numerous connective tissues store neuropsin in their secretory granules. The finding that the neuropsin transcript is maximally expressed in the intestine at the height of a helminth infection indicates that MC-committed progenitors selectively increase their expression of neuropsin as they develop into mature mucosal MCs. This is the first report documenting the expression of neuropsin in an immune cell. Thus, it is now apparent that mouse MCs store at least two distinct families of tryptic-like proteases in their secretory granules.

Animals↗