Biomedical subjects

Shoji Kagami

Publications and source records attributed to Shoji Kagami.

31 records · Page 2Linked to original sources

PubMed2004

Ebselen inhibits tumor necrosis factor-alpha-induced c-Jun N-terminal kinase activation and adhesion molecule expression in endothelial cells.

Tumor necrosis factor-alpha (TNF-alpha) stimulates expression of endothelial cell (EC) genes that may promote atherosclerosis in part by an activation of mitogen-activated protein (MAP) kinases. Ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]-one), a selenoorganic compound, is effective for acute ischemic stroke; however, its effect on EC has not yet been elucidated. We examined the effect of ebselen on TNF-alpha-induced MAP kinase activation and adhesion molecule expression in cultured human umbilical vein endothelial cells (HUVEC). Extracellular signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 were rapidly and significantly activated by TNF-alpha in HUVEC. TNF-alpha-induced JNK activation was inhibited by ebselen, whereas ERK1/2 and p38 were not affected. Apoptosis signal-regulated kinase 1 (ASK1) was suggested to be involved in TNF-alpha-induced JNK activation because transfection of kinase-inactive ASK1 inhibited TNF-alpha-induced JNK activation. Ebselen inhibited TNF-alpha-induced TNF receptor-associated factor 2 (TRAF2)-ASK1 complex formation and phosphorylation of stress-activated protein kinase ERK kinase 1 (SEK1), which is an upstream signaling molecule of JNK. Finally, TNF-alpha-induced activator protein-1 (AP-1) and nuclear factor-kappaB (NF-kappaB) activation and resultant intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expressions were inhibited by ebselen. Specific inhibitors for JNK and NF-kappaB also inhibited TNF-alpha-induced ICAM-1 and VCAM-1 expressions in HUVEC. These findings suggest that ebselen prevents TNF-alpha-induced EC activation through the inhibition of TRAF2-ASK1-SEK1 signaling pathway, which leads to JNK activation. Inhibition of JNK by ebselen may imply its usefulness for the prevention of atherosclerosis relevant to EC activation.

Azoles↗

PubMed2004

PDGF-BB enhances alpha1beta1 integrin-mediated activation of the ERK/AP-1 pathway involved in collagen matrix remodeling by rat mesangial cells.

Platelet-derived growth factor-BB (PDGF-BB) has been implicated in the pathogenesis of progressive glomerulonephritis (GN). Previous studies have reported that PDGF-BB stimulates mesangial cells (MCs)-induced collagen matrix remodeling through enhancement of alpha1beta1 integrin-dependent migratory activity. To determine the cell signaling pathway responsible for abnormal MC-related mesangial matrix remodeling in progressive GN, we studied the involvement of the extracellular signal-regulated kinase (ERK)/activator protein-1 (AP-1) pathway in PDGF-BB-enhanced collagen gel contraction. Western blotting and gel shift assay revealed that MC-induced gel contraction resulted in ERK activation in parallel with that of AP-1 binding, peaking at 4 h and lasting at least for 24 h. Application of the MEK inhibitor, U0126, and the c-jun/AP-1 inhibitor, curcumin, inhibited gel contraction and AP-1 activity, respectively, dose dependently. PDGF-BB enhanced not only gel contraction but ERK phosphorylation and AP-1 activity by MCs. Marked inhibitory effects on PDGF-BB-induced gel contraction and ERK/AP-1 activity were observed in the presence of either function blocking anti-alpha1- or anti-beta1-integrin antibody or U0126. Consistently, AP-1-inactive MCs expressing a dominant-negative mutant of c-jun showed a significant decrease of PDGF-BB-induced gel contraction as compared with mock-transfected MCs. Finally, migration assay showed that ERK/AP-1 activity is required for PDGF-BB-stimulated alpha1beta1 integrin-dependent MC migration to collagen I. These results indicated that PDGF-BB enhances alpha1beta1 integrin-mediated collagen matrix reorganization through the activation of the ERK/AP-1 pathway that is crucial for MC migration. We conclude that the ERK/AP-1 pathway plays an important role in PDGF-BB-induced alpha1beta1 integrin-dependent collagen matrix remodeling; therefore, the inhibition of its pathway may provide a novel approach to regulate abnormal collagen matrix remodeling in progressive GN.

Animals↗

PubMed2004

The SOD mimetic tempol ameliorates glomerular injury and reduces mitogen-activated protein kinase activity in Dahl salt-sensitive rats.

It was shown recently that renal injury in Dahl salt-sensitive (DS) hypertensive rats is accompanied by mitogen-activated protein kinase (MAPK) activation. The present study was conducted to elucidate the contribution of reactive oxygen species to MAPK activities and renal injury in DS rats. DS rats were maintained on high salt (H; 8.0% NaCl; n = 7) or low salt (L; 0.3% NaCl; n = 6) diets; H + a superoxide dismutase mimetic, tempol (3 mmol/L in drinking water; n = 8); or H + hydralazine (0.5 mmol/L in drinking water; n = 8) for 4 wk. Mean BP (MBP) in DS/H and DS/L rats was 185 +/- 7 and 113 +/- 3 mmHg, respectively. DS/H rats showed a higher ratio of urinary protein excretion and creatinine (U(protein)V/U(cr)V; 20.3 +/- 1.1) and a higher cortical collagen content (22 +/- 1 micro g/mg) than in DS/L rats (2.4 +/- 0.1 and 13 +/- 1 micro g/mg, respectively). The expression of p22-phox and Nox-1, essential components of NAD(P)H oxidase, in renal cortical tissue was approximately threefold higher in DS/H rats than in DS/L rats. Increased activities of renal cortical MAPK, including extracellular signal-regulated kinases (ERK) 1/ERK2 and c-Jun NH(2)-terminal kinases (JNK) were also observed in DS/H rats by 7.0 +/- 0.7- and 4.3 +/- 0.2-fold, respectively. Tempol treatment significantly decreased MBP (128 +/- 3 mmHg), U(protein)V/U(cr)V (4.8 +/- 0.4), and cortical collagen content (14 +/- 1 micro g/mg) and normalized ERK1/ERK2 and JNK activities in DS/H rats. Histologically, tempol markedly ameliorated progressive sclerotic and proliferative glomerular changes in DS/H rats. Hydralazine-treated DS/H rats showed similar MBP (127 +/- 5 mmHg) to tempol-treated DS/H rats. Hydralazine also decreased U(protein)V/U(cr)V (16.2 +/- 1.5) and cortical collagen content (19 +/- 1 micro g/mg) in DS/H rats. However, these values were significantly higher than those of tempol-treated rats. Furthermore, although hydralazine significantly reduced JNK activity (-56 +/- 3%), ERK1/ERK2 activities were unaffected. These data suggest that reactive oxygen species, generated by NAD(P)H oxidase, contribute to the progression of renal injury through ERK1/ERK2 activation in DS/H hypertensive rats.

Animals↗

PubMed2004

BMK1 is activated in glomeruli of diabetic rats and in mesangial cells by high glucose conditions.

BACKGROUND: High glucose causes renal cell injury through various signal transduction pathways, including mitogen-activated protein (MAP) kinases cascades. Big MAP kinase 1 (BMK1), also known as extracellular signal-regulated kinase 5 (ERK5), is a recently identified MAP kinase family member and was reported to be sensitive to osmotic and oxidative stress. However, the role of BMK1 in diabetic nephropathy has not been elucidated yet. METHODS: We investigated whether BMK1 is activated in the glomeruli of Otsuka Long Evans Tokushima Fatty (OLETF) rats, a model of type 2 diabetes mellitus in comparison with the control Long Evans Tokushima Otsuka (LETO) rats. We also examined the effect of high glucose on BMK1 activity in cultured rat mesangial cells. RESULTS: BMK1 and ERK1/2 but not p38 were activated in the glomeruli of OLETF rats, which showed diabetic nephropathy at 52 weeks of age. High glucose, in addition to a high concentration of raffinose, caused rapid and significant activation of BMK1 in rat mesangial cells. MAP kinase/ERK kinase (MEK) inhibitors, U0126 and PD98059, both inhibited BMK1 activation by high glucose in a concentration-dependent manner. Protein kinase C (PKC) inhibition by GF109203X and PKC down-regulation with long-time phorbol myristate acetate (PMA) treatment both inhibited BMK1 and Src kinase activation. Src kinase inhibitors, herbimycin A and PP2, also inhibited high glucose-induced BMK1 activation. PKC inhibitors, Src inhibitors and MEK inhibitors, all inhibited cell proliferation by high glucose. Finally, transfection of dominant-negative MEK5, which is an upstream regulator of BMK1, abolished the BMK1-mediated rat mesangial cell proliferation stimulated by high glucose. CONCLUSION: In the present study, we demonstrated that high glucose activates BMK1 both in vivo and in vitro. It was suggested that high glucose induces PKC- and c-Src-dependent BMK1 activation. It could not be denied that BMK1 activation is induced through an osmotic stress-sensitive mechanism. BMK1-mediated mesangial cell growth may be involved in the pathogenesis of diabetic nephropathy.

Animals↗

PubMed2004

Src and Cas are essentially but differentially involved in angiotensin II-stimulated migration of vascular smooth muscle cells via extracellular signal-regulated kinase 1/2 and c-Jun NH2-terminal kinase activation.

Angiotensin II (Ang II) plays an important role in several cardiovascular diseases associated with vascular smooth muscle cell (VSMC) growth and migration. Src activity is known to be required for the migration of a number of cell types. p130Cas was reported to be essential for cell migration and actin filament reorganization. Mitogen-activated protein (MAP) kinases were also reported to be critical regulatory factors for growth and migration of VSMC. However, precise intracellular mechanisms involving c-Src, p130Cas, and MAP kinases in Ang II-stimulated migration of VSMC have not been well elucidated. Here we demonstrated that Ang II rapidly and significantly stimulated tyrosine phosphorylation of Src and Cas and their association in rat aortic smooth muscle cells (RASMC). Ang II-stimulated tyrosine phosphorylation of Src and Cas and activation of ERK1/2 and JNK, but not p38, were potently inhibited by Src family tyrosine kinase inhibitors, herbimycin A (HA) and PP2. Ang II-stimulated Src and Cas association, tyrosine phosphorylation of Cas, and activation of ERK1/2 and JNK were suppressed in kinase-inactive Src (KI Src)-overexpressed RASMC. Ang II-stimulated JNK activation but not ERK1/2 activation was blocked in substrate domain-deleted Cas (DeltaSD Cas)-overexpressed RASMC. In addition, HA, PP2, ERK1/2 inhibitor, 2'-amino-3'-methoxyflavone (PD98059) and JNK inhibitor, and anthra[1,9-cd]pyrazol-6(2H)-one (SP600125) significantly inhibited Ang II-stimulated migration of RASMC. Ang II-induced colocalization of Src and Cas and migration were inhibited in both KI Src- and DeltaSD Cas-overexpressed RASMC. These findings suggest that Src and Cas are essentially but differentially involved in Ang II-stimulated migration of VSMC through the activation of ERK1/2 and JNK.

Angiotensin II↗

PubMed2004

Dual effects of endothelin-1 (1-31): induction of mesangial cell migration and facilitation of monocyte recruitment through monocyte chemoattractant protein-1 production by mesangial cells.

We previously found that human chymase selectively cleaves big endothelin-1 (ET-1) at the Tyr31-Gly32 bond and produces 31-amino acid endothelins, ET-1 (1-31), without any further degradation products. In this study, we investigated the effect of ET-1 (1-31) on the migration of cultured rat mesangial cells (RMCs) and on cells of the human monocytic cell line, THP-1. In addition, we examined the interaction between RMCs and THP-1 cells using conditioned media from ET-1 (1-31)-stimulated RMCs. ET-1 (1-31) caused an increase in RMC migration in a concentration-dependent manner, and the degree of increase was similar to those by ET-1 and angiotensin II (All). The ET-1 (1-31)-induced increase in RMC migration was inhibited by BQ123, an endothelin ETA receptor antagonist, but not by BQ788, an endothelin ETB receptor antagonist. ET-1 (1-31) alone did not cause significant migration of THP-1 cells. However, significant recruitment of THP-1 cells was observed with conditioned media taken from ET-1 (1-31)-stimulated RMCs. The conditioned media-induced migration of THP-1 cells was inhibited by BQ123, but not by BQ788. Western blotting analysis of the lysate of RMCs revealed that the expression of monocyte chemoattractant protein-1 (MCP-1) protein in RMCs was increased by treatment with ET-1 (1-31). The addition of neutralizing antibody for MCP-1 to the medium inhibited the migration of THP-1 cells induced by conditioned media from ET-1 (1-31)-stimulated RMCs. These findings suggest that ET-1 (1-31) play a role in glomerulonephritis (GN) via dual effects that directly cause the migration of mesangial cells (MCs) and may be responsible for the recruitment of mononuclear cells mediated through the activation of MCs. Since human chymase has been reported to be involved in glomerular disease, ET-1 (1-31) may be among the mediators.

Animals↗

PubMed2004

Beta1-integrins and glomerular injury.

The renal glomerulus is composed of three types of glomerular cells (mesangial cell (MC), endothelial cell and podocyte) and extracellular matrix (ECM) consisting of the glomerular basement membrane (GBM) and mesangial matrix. It constitutes a highly specialized microcirculation in which the permeability characteristics of the capillary wall allow its unique filtration function. The proliferation of MCs, an increase of mesangial ECM and detachment podocyte from GBM are key biological features of progressive glomerulonephritis (GN), leading to glomerular scarring and dysfunction. Thus, the study of the molecular and cellular mechanisms responsible for pathological glomerular alterations may help to elucidate the pathogenesis of progressive glomerular diseases. A growing body of evidence indicates that beta1 integrin family (beta1 integrins), that mainly mediates cell adhesion to ECM, controls cell behaviors such as cell migration, proliferation, apoptosis and ECM assembly. In addition, a correlation between glomerular expression of beta1 integrins and their ligand ECM components is observed in various human and experimental GN, suggesting that altered beta1 integrins-mediated cell behaviors may contribute to the progression of GN. It is now becoming apparent that the expression of glomerular beta1 integrins is not only critical for maintaining the glomerular capillary permeability but it modulates cell signaling pathways regulating the cell phenotypes involved in the progression of glomerular diseases.

Animals↗

PubMed2003

The role of mast cells in acute tubulo-interstitial nephritis with uveitis.

UNLABELLED: We describe the clinicopathological characteristics of two patients with acute tubulo-interstitial nephritis with uveitis (TINU) with mast cells infiltrating the interstitium. The pathogenesis of TINU remains unknown, but a T-cell-mediated immune response was suggested to be involved. Recent studies have shown that infiltrating mast cells are closely associated with the development of renal interstitial fibrosis in glomerulonephritis. To address the role of mast cells in the renal interstitial injury in TINU, immunohistochemical studies were performed in renal biopsy sections using anti-human mast cell tryptase antibody specific for mast cells. In addition, we tried to detect CD68-positive macrophages to compare with the localisation of mast cells within the renal interstitium. Mast cells and macrophages could be detected in renal interstitial lesions of both patients. Massive infiltration of macrophages into interstitial lesions was observed, whereas mast cells were detected in a sporadic rather than a clustered manner, and associated with fibrotic lesions. Repeat renal biopsy findings suggested the involvement of these cells in the renal interstitial injury because the number of infiltrating mast cells and macrophages in the interstitium decreased with the improvements in clinical symptoms and pathological lesions. CONCLUSION: The present study showed that mast cells might play an important role in the development of renal interstitial injury in tubulo-interstitial nephritis with uveitis.

Acute Disease↗

PubMed2002

Hydrogen peroxide stimulates c-Src-mediated big mitogen-activated protein kinase 1 (BMK1) and the MEF2C signaling pathway in PC12 cells: potential role in cell survival following oxidative insults.

Reactive oxygen species, generated by reduction-oxidation (redox) reactions, have been recognized as one of the major mediators of ischemia and reperfusion injury in the brain. Reactive oxygen species-induced cerebral events are attributable, in part, to the change in intracellular signaling molecules including mitogen-activated protein (MAP) kinases. Big MAP kinase 1 (BMK1), also known as ERK5, is a newly identified member of the MAP kinase family and has been reported to be sensitive to oxidative stress. In the present study, we examined the effect of H(2)O(2) on BMK1 activity in PC12 cells, and we investigated the pathophysiological implication of BMK1. Findings showed that BMK1 was rapidly and significantly activated by H(2)O(2) in a concentration-dependent manner in PC12 cells. BMK1 activation by H(2)O(2) was inhibited by both PD98059 and U0126, which were reported to inhibit MEK5 as well as MEK1/2. c-Src was suggested to be involved in BMK1 activation from the experiments with herbimycin A and PP2, specific inhibitors of Src family kinases. Transfection of kinase-inactive Src also inhibited H(2)O(2)-induced BMK1 activation. In addition, H(2)O(2) treatment of cells induced an enhancement of DNA binding activity of MEF2C, a downstream transcription factor of BMK1 in PC12 cells. Finally, pretreatment of cells with PD98059 and U0126 resulted in an increase in cell death including apoptosis by H(2)O(2) in ERK1/2 down-regulated cells as well as in intact PC12 cells. These findings suggest that c-Src mediated BMK1 activation by H(2)O(2) may counteract ischemic cellular damage probably through the activation of MEF2C transcription factor.

Animals↗

PubMed2002

Ebselen attenuates oxidative stress-induced apoptosis via the inhibition of the c-Jun N-terminal kinase and activator protein-1 signalling pathway in PC12 cells.

1: Ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]-one) is a selenoorganic compound exhibiting both glutathione peroxidase activity and antioxidant activity. Although it has been reported that ebselen is effective for oxidative stress-induced neuronal damage both in vivo and clinically, the precise mechanisms of the efficacy have not yet been elucidated. Thus, we hypothesized that ebselen may affect reactive oxygen species-induced mitogen-activated protein (MAP) kinase activation in cultured PC12 cells. 2: Our findings showed that hydrogen peroxide (H(2)O(2)) stimulated rapid and significant activation of extracellular signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK) and p38 in PC12 cells, which is a model of catecholamine-containing neurons. 3: H(2)O(2)-induced JNK activation was inhibited by ebselen, whereas ERK1/2 and p38 activation by H(2)O(2) were not affected by ebselen. 4: Inhibition by ebselen of H(2)O(2)-induced hydroxyl radical generation in PC12 cells was observed using electron paramagnetic resonance measurements. Ebselen also inhibited H(2)O(2)-induced increases in DNA binding activity of activator protein-1 (AP-1), a downstream transcription factor of JNK, composed of the c-Jun homo/heterodimer. 5: Finally, pretreatment of cells with ebselen resulted in a significant recovery from cell death including apoptosis by H(2)O(2) in PC12 cells. 6 These findings suggest that ebselen attenuates oxidative stress-induced neuronal cell death through the inhibition of the JNK and AP-1 signalling pathway. Thus, inhibition of JNK by ebselen may imply its usefulness for treatment of ischaemic cerebral diseases relevant to neuronal cell death.

Analysis of Variance↗

PubMed2002

Glomerular distribution and gelatinolytic activity of matrix metalloproteinases in human glomerulonephritis.

BACKGROUND: Matrix metalloproteinases (MMPs) have been implicated in the development of glomerular injury in rat experimental glomerulonephritis (GN). However, the significance of MMPs in human GN remains obscure. In order to evaluate the role of MMPs in human GN, we examined the glomerular distribution and gelatinolytic activities of MMP-2 and MMP-9 in human GN. METHODS: We performed immunohistochemistry with polyclonal anti-MMP-2 and MMP-9 antibodies, and analysed gelatin zymograms of five isolated glomeruli from various types of human renal disease. The renal specimens investigated were from normal kidneys (n=5), IgA nephritis (n=20), Henoch-Schönlein nephritis (n=4), non-IgA mesangial proliferative GN (n=9), lupus nephritis (n=6), acute poststreptococcal GN (APSGN) (n=4) and diabetic nephropathy (DN) (n=4). RESULTS: MMP-2 immunoreactivity was not detected in normal controls or in any type of GN. MMP-9 staining, which was almost negative in normal glomeruli, was increased mainly in the mesangial region and corresponded to the level of glomerular cell proliferative changes in mesangial proliferative GN (IgA nephritis, Henoch-Schönlein nephritis, non-IgA mesangial proliferative GN and lupus nephritis). Positive but weak staining for MMP-9 was observed in mesangial areas in DN. In addition, double immunostaining showed that MMP-9 is colocalized in scattered neutrophils within diseased glomeruli in APSGN. MMP-9 gelatinolytic activity in five normal glomeruli was weakly detected. Consistent with the levels of immunostaining, MMP-9 glomerular activity was dramatically increased in nephritic glomeruli with IgA nephritis, lupus nephritis and DN. The gelatinolytic activity of MMP-2 was occasionally detectable in nephritic glomeruli. CONCLUSION: These results strongly suggest that MMP-9 plays an important role in abnormal mesangial proliferative changes in human GN.

Cell Division↗

PubMed2002

Effects of anti-alpha1 integrin subunit antibody on anti-Thy-1 glomerulonephritis.

alpha1beta1 integrin is a potential collagen-binding extracellular matrix receptor that mediates collagen-dependent cell adhesion, proliferation, migration, and collagen matrix assembly and thereby may participate in the wound healing and pathologic scarring observed in some damaged organs. To clarify the role of alpha1beta1 integrin predominantly expressed on the mesangial cell (MC) surface in nephritic glomeruli, we investigated the involvement of MC-alpha1beta1 integrin in rat anti-Thy-1 glomerulonephritis (GN) by administering function-blocking monoclonal mouse anti-rat alpha1 integrin subunit antibody (anti-alpha1 Ab). Assay of collagen types I and IV mixed gel contraction, an in vitro model of pathologic collagen matrix remodeling, with function-blocking anti-alpha1 Ab and anti-beta1 Ab, revealed that collagen I and IV matrix reorganization is mediated by MC-alpha1beta1 integrin. In addition, conditioned medium from isolated Day 3 anti-Thy-1 nephritic glomeruli showed increased activity of MC-alpha1beta1 integrin-induced mixed collagen gel contraction as compared with that from isolated normal rat glomeruli. Treatment of Day 3 conditioned medium with anti-platelet-derived growth factor-BB antibody significantly inhibited conditioned media-induced gel contraction, whereas treatment with anti-transforming growth factor-beta antibody did not have a significant effect. Rats that received anti-alpha1 Ab from the left renal artery 3 days after anti-Thy-1 GN induction showed significant decreases of glomerular hypercellularity and mesangial matrix accumulation, including collagen I and IV in the left kidney, compared with those rats in which the left kidney received control mouse IgG1. These results suggest that MC-alpha1beta1 integrin is an important extracellular matrix receptor mediating mesangial remodeling characterized by MC proliferation and mesangial matrix reorganization in anti-Thy-1 GN. Platelet-derived growth factor-BB may be involved in early collagen matrix reorganization leading to pathologic mesangial remodeling in this GN model.

Animals↗

PubMed2001

Role of mast cell tryptase in renal interstitial fibrosis.

Renal interstitial fibrosis is characterized by increased proliferation of fibroblasts and excessive accumulation of extracellular matrix. Mast cell tryptase has been implicated in the development of tissue fibrosis in skin and lungs. However, the significance of mast cell tryptase in human renal diseases has not been investigated. The potential role of mast cell-derived tryptase in the development of renal fibrosis was studied using immunohistochemical techniques and cultured human renal fibroblast cell lines. Semiquantitative immunostaining analysis of samples from 70 patients with several renal diseases, including IgA glomerulonephritis (GN) (n = 30), non-IgA GN (n = 5), membranous GN (n = 5), focal segmental glomerulosclerosis (n = 4), minor glomerular abnormalities (n = 5), lupus nephritis (n = 3), and acute or chronic tubulointerstitial nephritis (n = 18), revealed that the degree of renal interstitial fibrosis was well correlated with the number of infiltrating tryptase-positive mast cells (P < 0.01). Mast cells could not be detected in damaged glomeruli in any form of renal disease. [(3)H]Thymidine uptake experiments demonstrated that DNA synthesis by cultured renal fibroblasts was increased with the concentration of tryptase (0.5 to 5 nM) coincubated with heparin and was suppressed by coincubation with the protease inhibitors leupeptin and benzamidine hydrochloride. Tryptase alone also increased DNA synthesis by fibroblasts but exhibited less effectiveness, compared with the combination of tryptase and heparin. Conversely, heparin alone suppressed DNA synthesis by fibroblasts. Metabolic [(35)S]methionine-labeling experiments with cultured renal fibroblasts indicated that tryptase increased the synthesis of fibronectin and collagen type I, in a dose-dependent manner. These findings suggest that mast cell tryptase plays a role in the proliferation and extracellular matrix protein production of renal interstitial fibroblasts and thus contributes to the development of renal interstitial fibrosis.

Cell Division↗