Smooth Muscle Research Group, Department of Pharmacology and Therapeutics, University of Calgary, Calgary, Alberta, Canada T2N 4N1
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ABSTRACT |
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Proteinase-activated receptors (PARs) are a novel class of G protein-coupled receptors that respond to signals through endogenous proteinases. PAR activation involves enzymatic cleavage of the extracellular NH2-terminal domain and unmasking of a new NH2 terminus, which serves as an anchored ligand to activate the receptor. At least four PAR subtypes have been identified. In the present study, we used the in vitro perfused hydronephrotic rat kidney to examine the effects of activating PAR-2 on the afferent arteriole. The synthetic peptide SLIGRL-NH2, which corresponds to the exposed ligand sequence and selectively activates PAR-2, did not alter basal afferent arteriolar diameter but caused a concentration-dependent vasodilation (3-30 µM) of arterioles preconstricted by angiotensin II (0.1 nM). A modified peptide sequence (LSIGRL-NH2, inactive at PAR-2) had no effect. This vasodilation was characterized by an initial transient component followed by a smaller sustained response. A similar pattern of vasodilation was seen when SLIGRL-NH2 was administered to isolated perfused normal rat kidney. The sustained component of the PAR-2-induced afferent arteriolar vasodilation was eliminated by nitric oxide (NO) synthase inhibition (100 µM nitro-L-arginine methyl ester). In contrast, the transient vasodilation persisted under these conditions. This transient response was not observed when afferent arterioles were preconstricted with elevated KCl, suggesting involvement of an endothelium-derived hyperpolarizing factor. Finally, RT-PCR revealed the presence of PAR-2 mRNA in isolated afferent arterioles. These findings indicate that PAR-2 is expressed in the afferent arteriole and that its activation elicits afferent arteriolar vasodilation by NO-dependent and NO-independent mechanisms.
microcirculation; endothelium; proteinase; angiotensin II; potassium chloride; nitric oxide
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INTRODUCTION |
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PROTEASES SUCH AS TRYPSIN and thrombin activate a novel class of G protein-linked receptors termed proteinase-activated receptors (PARs) (7, 21). Four members on this class of receptors, PAR-1, PAR-2, PAR-3, and PAR-4, have been described (15-17, 26, 34, 36). PARs are activated by enzymatic cleavage of the extracellular NH2 terminus to reveal a new NH2 terminus containing a specific amino acid sequence that acts as a tethered ligand for the receptor. PAR-2 is unique, in that it is activated by trypsin and mast cell-derived tryptase (8, 26) but not by thrombin (26). PAR-2 can also be activated by a synthetic peptide corresponding to the enzymatically exposed ligand sequence SLIGRL or SLIGRL-NH2 (26, 30-32) and is expressed in vascular and nonvascular smooth muscle (25, 31) and in vascular endothelium (22).
Previous investigations of renal PARs have focused primarily on the
thrombin receptor PAR-1. Activation of PAR-1 was shown to stimulate
mesangial cell proliferation (2) and is implicated in the
inflammatory events of crescentic glomerular nephritis (9). Thrombin is likely involved in fibrin and
extracelluar matrix deposition during renal inflammation (11,
12), possibly by the activation of PAR-1. There is little
information on the functional effects of renal PAR-2 activation.
Nevertheless, PAR-2 is abundantly expressed in human (6)
and mouse (26) kidney. Immunohistochemical studies
demonstrate PAR-2 in renal epithelial cells, renal vascular
endothelium, and vascular smooth muscle (4). PAR-2 has
been shown to activate a Cl conductance in cortical
collecting duct cells (4). However, the effects of PAR-2
activation on the renal microcirculation have not been investigated. In
the present study, using the peptide sequence specific for PAR-2, we
determined the renal afferent arteriolar actions of PAR-2. The effects
of PAR-2 activation under basal conditions and during angiotensin II-
and KCl-induced vasoconstriction were investigated using the in vitro
perfused hydronephrotic rat kidney. Our findings indicate that PAR-2 is
a potent vasodilator of the afferent arteriole and that its actions
involve NO-dependent and NO-independent mechanisms.
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METHODS |
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In vitro perfused hydronephrotic kidney studies. The in vitro perfused hydronephrotic rat kidney model (33) was employed to study the effects of PAR-2 activation on the renal afferent arteriole. Unilateral hydronephrosis was induced by ligating the left ureter of young male Sprague-Dawley rats under halothane-induced anesthesia. Kidneys were harvested after 6-8 wk, when the tubular atrophy allows direct visualization of the microvasculature. Animals were anesthetized with methoxyflurane, the left renal artery was cannulated in situ, and the kidney was excised with continuous perfusion.
Kidneys were perfused using a single-pass perfusion system (33). Perfusion pressure, monitored within the renal artery, was maintained at 80 mmHg by an automated pressure controller (Biomedical Instruments, University of Calgary). The perfusate consisted of Dulbecco's modified Eagle's medium (Sigma) containing 30 mM bicarbonate, 5 mM glucose, and 5 mM HEPES (GIBCO). The medium was equilibrated with 95% air-5% CO2. Temperature was maintained at 37°C and pH at 7.4. Pharmacological agents were added directly to the perfusate.In vitro perfused normal kidney studies. The isolated perfused normal rat kidney model was used to assess the effects of PAR-2 activation in the nonhydronephrotic rat kidney. For these studies, kidneys were harvested from 300-g male Sprague-Dawley rats under methoxyflurane-induced anesthesia. The normal kidneys were perfused with an identical perfusate, and flow was monitored using a transit flowmeter (model T106, Transonic Systems, Ithaca, NY). After isolation, the kidneys were allowed to equilibrate for 20 min before the experimental protocol. In these studies, kidneys were pretreated with 10 µM ibuprofen.
RT-PCR studies of isolated afferent arterioles. Our recently described method of isolating single afferent arterioles (20) was employed to obtain vessels from normal kidneys for assessment of PAR-2 mRNA expression. Briefly, normal rat kidneys were flushed in situ with warmed medium and then perfused with a 2% agarose solution. The kidneys were chilled to solidify the agarose. Individual afferent arterioles were isolated by enzymatic dispersion (collagenase IV, dispase II, and DNase I) of thin cortical slices. Isolated arterioles were washed three times and pooled (25-30 vessels) for RT-PCR. Total RNA was extracted with the RNeasy Mini Kit (Qiagen, Mississauga, ON, Canada). The extracted RNA was reverse transcribed with a first-strand cDNA synthesis kit using Pd(N)6 primer (Pharmacia, LKB Biotechnology, Uppsala, Sweden) at 37°C for 60 min. The reverse transcription product then was used for PCR. Amplification was performed using a denaturation period of 1 min (94°C), a reannealing period of 45 s (55°C), and an extension period of 1 min (68°C) for 35 cycles. The PCR products were separated using 1.5% agarose gel electrophoresis and visualized by ethidium bromide staining. The primer pairs for PAR-2 were 5'-CAACAGCTGCAT(T/A)GACCCCTT-3' (forward) and 5'-CCCGGGCTCAGTAGGAGGTTTTAACAC-3' (reverse). The 190-bp product of these primers was purified (Magic DNA Purification Kit, Promega, Madison, WI), sequenced (Sequencing Facility, Faculty of Medicine, University of Calgary), and found to match the published rat PAR-2 sequence (31). The actin primers, which span an intron, were 5'-CGTGGGCCGCCCTAGGCACCA-3' (forward) and 5'-TTGGCCTTAGGGTTCAGGGGG-3' (reverse). These actin primers yield a 243-bp product.
Materials. The synthetic PAR-2 peptides SLIGRL-NH2 and LSIGRL-NH2 (>95% pure by HPLC and mass spectral criteria) were prepared by Immunosystems at BioChem Therapeutic (Laval, PQ, Canada) or by the Peptide Synthesis Facility at the Faculty of Medicine, University of Calgary. Stock solutions were prepared in 25 mM HEPES, pH 7.4, and concentrations were verified by quantitative amino acid analysis. Angiotensin II was obtained from Sigma-Aldrich Chemical (Oakville, ON, Canada), ibuprofen from Research Biomedicals International (Natick, MA), and nitro-L-arginine methyl ester (L-NAME) from Bachem (Torrance, CA).
Analysis of data. Video images were digitized (model IVG-128, Datacube, Peabody, MA) for on-line analysis as previously described. Afferent arteriolar diameter was measured at each pixel and averaged over the entire segment length (~20 µm) at a sampling rate of ~1 Hz. The diameter measurements thus obtained were then averaged over the peak of the response or when the response had reached the plateau. Each diameter determination was the result of ~100 individual measurements, each representing the mean diameter over the 20-µm scanning window of the vessel. Values are means ± SE. The number of replicates refers to the number of arterioles examined. Only one vessel was studied in each kidney preparation. Differences between means were evaluated by ANOVA. For multiple comparisons, Bonferroni's correction was applied. In all cases, differences with P < 0.05 were considered to be statistically significant.
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RESULTS |
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The peptide sequence SLIGRL-NH2 corresponds to the activation sequence within the extracellular NH2-terminal domain of the PAR-2 receptor and is a PAR-2-selective agonist. In the in vitro perfused hydronephrotic rat kidney model, SLIGRL-NH2 had no effect on basal afferent arteriolar diameter at concentrations as high as 30 µM: 16.9 ± 0.2 µm in control, 17.3 ± 0.3 µm after 10 µM SLIGRL-NH2 (P > 0.1, n = 4), and 17.4 ± 0.3 µm for 30 µM SLIGRL-NH2 (P > 0.5, n = 4). When administered after NO synthase inhibition (100 µM L-NAME), 10 µM SLIGRL-NH2 elicited a modest vasoconstriction, reducing afferent arteriolar diameter from 16.1 ± 0.5 to 14.2 ± 1.0 µm (P < 0.05, n = 8).
When administered during angiotensin II-induced vasoconstriction,
SLIGRL-NH2 elicited a biphasic vasodilator response. As shown in Fig. 1, the response was
characterized by an initial peak response, which was followed by a
reduced, but sustained, vasodilation. In this experiment, angiotensin
II reduced afferent arteriolar diameter from 16 to 8 µm.
SLIGRL-NH2 (10 µM) evoked a strong initial vasodilation,
which peaked at 14 µm. However, the diameter spontaneously returned
to 10 µm within 5 min. Concentration-response studies were conducted
using the PAR-2-activating peptide. Because PAR-2 can exhibit
desensitization (10), we could not rely on a cumulative
dose-response approach. To circumvent this potential issue, we tested
one concentration of the peptide, allowed the preparation to recover
for 1 h, and then tested a second concentration. Thus only two
concentrations were examined in each preparation. In this series, 0.1 nM angiotensin II reduced afferent arteriolar diameter from 16.7 ± 0.4 to 6.8 ± 0.5 µm. Figure 2
summarizes the mean concentration-response data obtained using this
approach. At 3 µM, SLIGRL-NH2 resulted in an increase in
afferent arteriolar diameter to a peak of 12.0 ± 1.2 µm
(P < 0.05) followed by a sustained dilation to
10.9 ± 1.4 µm (P < 0.05, n = 6). At 30 µM, SLIGRL-NH2 increased afferent arteriolar
diameter to a peak of 16.5 ± 0.5 µm, corresponding to a full
reversal of the angiotensin II-induced vasoconstriction. The diameter
subsequently returned to a sustained value of 13.1 ± 2.0 µm
(P < 0.05 vs. angiotensin II alone, n = 4). The IC50 for the peak component of the vasodilation
was ~3 µM. As a control, we examined the effects of
LSIGRL-NH2, a peptide in which the first two amino acids
are reversed. LSIGRL-NH2 has no activity at PAR-2. In these
studies, 0.1 nM angiotensin II reduced afferent arteriolar diameter
from 16.1 ± 0.4 to 7.3 ± 0.8 µm. LSIGRL-NH2
(10 µM) had no vasodilatory effect (7.4 ± 0.8 µm,
P > 0.5 compared with angiotensin II alone,
n = 4). After the administration of
LSIGRL-NH2, which did not elicit a response, the
application of 10 µM SLIGRL-NH2 evoked prompt
vasodilation.
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To determine whether the vasodilatory actions of SLIGRL-NH2
required NO synthesis, a separate series of kidneys were pretreated with 100 µM L-NAME. L-NAME treatment did not
significantly alter basal diameter: 17.1 ± 0.7 and 16.7 ± 0.6 µm for control and L-NAME, respectively
(P > 0.4, n = 4). As depicted in Fig.
3, in the presence of L-NAME,
SLIGRL-NH2 evoked only the transient component of the vasodilation. In this setting, angiotensin II reduced diameter from
16.7 ± 0.6 to 8.2 ± 1.4 µm. The application of 10 µM
SLIGRL-NH2 caused a transient increase in diameter to
13.3 ± 0.6 µm (P < 0.05 vs. angiotensin II
alone). Diameter returned to 6.7 ± 1.7 µm (P > 0.05) within 5 min.
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We observed similar effects of L-NAME on
acetylcholine-induced afferent arteriolar vasodilation (13, 33,
35). The transient vasodilation that is evoked by acetylcholine
in this setting has been suggested to be mediated by an
endothelium-derived hyperpolarizing factor (EDHF) and is prevented by
elevated extracellular potassium concentration (13, 35).
As shown in Fig. 4, elevated
extracellular potassium concentration (25 mM) also abolished the
L-NAME-insensitive component of the
SLIGRL-NH2-induced vasodilation. In controls (without
L-NAME or ibuprofen), KCl reduced afferent diameter from 18.4 ± 1.3 to 5.3 ± 0.6 µm. The addition of 10 µM
SLIGRL-NH2 reversed this response by 64 ± 7%,
increasing diameter to 13.6 ± 1.0 µm (n = 5, P < 0.01). In the presence of 10 µM ibuprofen, KCl
reduced diameter from 16.0 ± 0.9 to 4.3 ± 0.5 µm and
SLIGRL-NH2 increased diameter to 12.6 ± 0.9 µm
(n = 5, P < 0.05), corresponding to a
71 ± 5% dilation (P = 0.45 vs. control). In the
presence of both L-NAME and ibuprofen, KCl reduced diameter
from 16.8 ± 0.5 to 4.7 ± 0.1 µm. In this setting,
SLIGRL-NH2 was without effect: 4.8 ± 0.2 µm, a
0.6 ± 1.6% dilation (n = 5). These data are
summarized in Fig. 4, C and D.
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We next examined the responses of normal kidneys to
SLIGRL-NH2 perfused in vitro under identical conditions to
determine whether PAR-2 activation elicited similar actions in the
nonhydronephrotic kidney. As shown in Fig.
5, 10 µM SLIGRL-NH2 also
elicited a biphasic vasodilation in the normal kidney. In five such
preparations, 0.1 nM angiotensin II reduced renal perfusate flow from
15.1 ± 1.9 to 6.3 ± 0.9 ml · min1 · g
1. The
addition of 10 µM SLIGRL-NH2 increased mean flow to a
peak value of 11.8 ± 1.6 ml · min
1 · g
1, which
spontaneously abated to 10.0 ± 1.1 ml · min
1 · g
1 within 10 min. These data, normalized to the percentage of basal perfusate flow,
are presented in Fig. 5. We interpret these observations as indicating
that the PAR-2-activating peptide also evoked vasodilation in the
normal kidney and that the temporal character of this response is
similar to that in the afferent arteriole of the hydronephrotic kidney
preparation.
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Finally, we investigated whether the afferent arteriole expresses
message for PAR-2. We used RT-PCR to determine whether mRNA for PAR-2
is present in afferent arterioles that were isolated from normal rat
kidneys (20). As depicted in Fig.
6, we were able to detect a 190-bp
product from the cDNA isolated from the afferent arteriole using the
PAR-2 primers. This product was sequenced and shown to correspond to
the rat PAR-2 sequence (31).
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DISCUSSION |
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The major finding of this study is that PAR-2 activation elicits
afferent arteriolar vasodilation by NO-dependent and NO-independent mechanisms. Although PAR-2 is abundantly expressed in the kidney (6, 26), there is little current information on the impact of PAR-2 activation on renal function. Bertog et al. (4)
demonstrated, using antibody probes to PAR-2, that the receptor is
present on murine renal vascular and tubular tissues. These
investigators found PAR-2 to be localized to the basolateral side of
cortical collecting duct cells and found that PAR-2 activation
stimulated an apical Cl current, suggesting a functional
role in the distal portion of the nephron. Our findings indicate
that PAR-2 stimulation can also modulate renal function by evoking
afferent arteriolar vasodilation through mechanisms that are
classically associated with endothelial cell activation.
Previous studies using large arteries demonstrated endothelium-dependent vasodilatory responses to PAR-2-activating peptides (30, 31). The present report is the first to examine PAR-2 responses of the renal afferent arteriole. Our studies examining the flow response of the normal rat kidney and the afferent arteriolar response of the hydronephrotic kidney model demonstrate PAR-2-mediated renal vasodilation. The results of our RT-PCR assay confirm that the normal rat afferent arteriole expresses message for this receptor. In other vascular preparations where NO synthase was inhibited with L-NAME, the relaxation responses to PAR-2 activation were abolished (31). In the afferent arteriole, we found that NO synthase inhibition eliminated only the sustained component of the PAR-2 vasodilatory response. The initial peak afferent arteriolar vasodilation evoked by SLIGRL-NH2 was not affected by L-NAME but was abolished by 25 mM KCl. Elevated KCl eliminates vasodilator responses mediated by potassium channel activation (28). We suggest that the transient dilation elicited by PAR-2 activation may be mediated by an EDHF, whereas the sustained response required NO formation. EDHF responses to other endothelium-dependent vasodilators exhibit a similar transient character (3, 35). Although our studies cannot rule out a direct effect of PAR-2 on the afferent arteriolar smooth muscle, PAR-2-mediated vasodilation in other vascular preparations has been shown to be eliminated when the endothelium is mechanically removed (30, 31).
We previously showed that the afferent arteriolar response to
acetylcholine is sustained for 10-15 min (33). By
contrast, the afferent arteriolar vasodilation induced by PAR-2
activation was biphasic, in that it was composed of an initial
transient component followed by a reduced sustained phase. Only the
sustained component was blocked by L-NAME. The initial
transient response to 30 µM SLIGRL-NH2 attained a
near-maximal afferent arteriolar vasodilation, whereas the sustained
component was less robust (Figs. 1 and 2). A similar profile in the
perfusate flow response was observed when SLIGRL-NH2 was
administered to the in vitro perfused normal kidney (Fig. 5). By
contrast, SLIGRL-NH2 elicits a monophasic dilation of
conduit arteries (1, 30). One possible explanation for
this temporal profile is that, initially, a transient EDHF-dependent
component of the PAR-2 vasodilatory response predominates over the
sustained NO-dependent component. Alternatively, PAR-2 desensitization
could contribute to a diminishing effectiveness of
SLIGRL-NH2 during exposure to the agonist. Receptor
desensitization has been associated with enzymatic and agonist peptide
activation of PAR-2 (5, 10) but was not observed in
PAR-2-mediated relaxation of endothelium-intact rat aorta
(1). Moreover, in renal M-1 cells, only enzymatic
activation induces desensitization, whereas agonist peptide activation
of the receptor does not (4). Finally, it is possible that
SLIGRL-NH2 may concurrently activate another receptor
population that is associated with a delayed contractile effect. In
support of the latter postulate, we observed an
SLIGRL-NH2-induced afferent arteriolar vasoconstriction
after NO synthase inhibition. Previous studies using other vascular
preparations have demonstrated that SLIGRL-NH2 elicits
endothelium-dependent (30, 32) and endothelium-independent
(23) vasoconstriction.
We can only speculate on the physiological and pathophysiological implications of our findings. In vivo, PAR-2 may be enzymatically activated by serine proteases such as trypsin. However, PAR-2 has also been shown to be activated by mast cell-derived tryptase (8, 24), and endothelial PAR-2 can be elevated by inflammatory stimuli (27). Mast cells are present in very low numbers in the normal kidney, but the population of renal mast cells increases in conditions associated with chronic inflammation. Increases in renal mast cells have been demonstrated to be associated with glomerulonephritis, diabetic nephropathy, and renal graft rejection (14, 18, 29). During inflammatory events, proteinases are released and PAR-2 itself may be upregulated (27). PARs would likely be activated in these settings (8, 9). Lee et al. (19) reported that urine from patients with acute and chronic renal failure contains significant proteinase activity, whereas that from normal controls does not. Our findings suggest that proteinase activation of PAR-2 in the renal microcirculation would be associated with renal vascular NO production and a reduction in afferent arteriolar tone.
In summary, the present study demonstrates, for the first time, a functional response of the renal afferent arteriole to PAR-2 activation. Our findings suggest that PAR-2 elicits afferent arteriolar vasodilation by NO-dependent and NO-independent mechanisms. We suggest that the latter involves an EDHF-like response, in that it is prevented by elevated external potassium. These findings suggest that proteinase activation of renal microvascular PAR-2 would result in renal vasodilation. The physiological or pathophysiological role of this mechanism and the identification of renal proteases that might activate renal PAR-2 receptors in situ are important issues awaiting further study.
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ACKNOWLEDGEMENTS |
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The authors thank Dr. M. Saifeddine for expert advice on the use and handling of the PAR-2 peptides and Dr. B. Al-Ani for providing the PAR-2 primers.
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FOOTNOTES |
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These investigations were supported by grants from the Canadian Institutes for Health Research (R. Loutzenhiser and M. Hollenberg) and the Kidney Foundation of Canada (M. Hollenberg).
Address for reprint requests and other correspondence: R. D. Loutzenhiser, Dept. of Pharmacology and Therapeutics, The University of Calgary Health Sciences Centre, 3330 Hospital Dr. NW, Calgary, AB, Canada T2N 1N4 (E-mail: rloutzen{at}ucalgary.ca).
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
First published December 4, 2001;10.1152/ajprenal.00233.2001
Received 26 July 2001; accepted in final form 27 November 2001.
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REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1.
Al-Ani, B,
Saifeddine M,
and
Hollenberg MD.
Detection of functional receptors for the proteinase-activated receptor-2-activating polypeptide, SLIGRL-NH2, in rat vascular and gastric smooth muscle.
Can J Physiol Pharmacol
73:
1203-1207,
1995[ISI][Medline].
2.
Albrightson, CR,
Zabko-Potapovich B,
Dytko G,
Bryan WM,
Hoyle K,
Moore ML,
and
Stadel JM.
Analogues of the thrombin receptor-tethered ligand enhance mesangial cell proliferation.
Cell Signal
6:
743-750,
1994[ISI][Medline].
3.
Bakker, EN,
and
Simkema P.
Components of acetylcholine-induced dilation in isolated rat arterioles.
Am J Physiol Heart Circ Physiol
273:
H1848-H1853,
1997
4.
Bertog, M,
Letz B,
Kong W,
Steinhoff M,
Higgins MA,
Biefeld-Ackermann A,
Fromter E,
Bunnett NW,
and
Korbmacher C.
Basolateral proteinase-activated receptor (PAR-2) induces chloride secretion in M-1 mouse renal cortical collecting duct cells.
J Physiol (Lond)
521:
3-17,
1999
5.
Bohm, SK,
Khitin LM,
Grady EF,
Aponte G,
Payan DG,
and
Bunnett NW.
Mechanisms of desensitization and resensitization of proteinase-activated receptor-2.
J Biol Chem
36:
22003-22016,
1996.
6.
Bohm, SK,
Kong W,
Bromme D,
Smeekens SP,
Anderson DC,
Connolly A,
Kahn M,
Nelken NA,
Coughlin SR,
Payani DG,
and
Bunnett NW.
Molecular cloning, expression and potential functions of the human proteinase-activated receptor-2.
Biochem J
314:
1009-1016,
1996[ISI][Medline].
7.
Coughlin, SR.
Thrombin signalling and protease-activated receptors.
Nature
407:
258-264,
2000[ISI][Medline].
8.
Corvera, CU,
Déryo McConalogue K,
Gamp P,
Thoma M,
Al-Ani B,
Caughey GH,
Hollenberg MD,
and
Bunnett NW.
Thrombin and mast cell tryptase regulate guinea-pig myenteric neurons through proteinase-activated receptors-1 and -2.
J Physiol (Lond)
517:
741-756,
1999
9.
Cunningham, MA,
Rondeau E,
Chen X,
Coughlin SR,
Holdsworth SR,
and
Tipping PG.
Protease-activated receptor 1 mediates thrombin-dependent, cell-mediated renal inflammation in crescentic glomerulonephritis.
J Exp Med
191:
455-462,
2000
10.
Déry, O,
Corvera CU,
Steinhoff M,
and
Bunnett NW.
Proteinase-activated receptors: novel mechanisms of signaling by serine proteases.
Am J Physiol Cell Physiol
274:
C1429-C1452,
1998
11.
Grandaliano, G,
Gesualdo L,
Ranieri E,
Monno R,
and
Schena FP.
Tissue factor, plasminogen activator inhibitor-1, and thrombin receptor expression in human crescentic glomerulonephritis.
Am J Kidney Dis
35:
726-738,
2000[ISI][Medline].
12.
Grandaliano, G,
Monno R,
Ranieri E,
Gesualdo L,
Schena FP,
Martino C,
and
Ursi M.
Regenerative and proinflammatory effects of thrombin on human proximal tubular cells.
J Am Soc Nephrol
11:
1016-1025,
2000
13.
Hayashi, K,
Loutzenhiser R,
Epstein M,
Suzuki H,
and
Satura T.
Multiple factors contribute to acetylcholine-induced renal afferent arteriolar vasodilation during myogenic and norepinephrine- and KCl-induced vasoconstriction: studies in the isolated perfused hydronephrotic kidney.
Circ Res
75:
821-828,
1994[Abstract].
14.
Hiromura, K,
Kurosawa M,
Yano S,
and
Naruse T.
Tubulointerstitial mast cell infiltration in glomerulonephritis.
Am J Kidney Dis
32:
593-599,
1998[ISI][Medline].
15.
Hollenberg, MD.
Protease-activated receptors: PAR4 and counting: how long is the course?
Trends Pharmacol Sci
20:
271-273,
1999[ISI][Medline].
16.
Ishihara, H,
Connolly AJ,
Zeng D,
Kahn ML,
Zheng YW,
Timmons C,
Tram T,
and
Coughlin SR.
Protease-activated receptor 3 is a second thrombin receptor in humans.
Nature
386:
502-506,
1997[ISI][Medline].
17.
Kahn, ML,
Zheng YW,
Huang W,
Bigoinia V,
Zeng D,
Moff S,
Farese RV, Jr,
Tam C,
and
Coughlin SR.
A dual thrombin receptor system for platelet activation.
Nature
394:
690-694,
1998[ISI][Medline].
18.
Lajoie, G,
Nadasdy T,
Laszik Z,
Blick KE,
and
Silva FG.
Mast cells in acute cellular rejection of human renal allografts.
Mod Pathol
9:
1118-1125,
1996[ISI][Medline].
19.
Lee, DY,
Park SK,
Yorgin PD,
Cohen P,
Oh Y,
and
Rosenfeld RG.
Alterations in insulin-like growth factor-binding proteins (IGFBPs) and IGBBP-3 protease activity in serum and urine from acute and chronic renal failure.
J Clin Endocrinol Metab
79:
1376-1382,
1994[Abstract].
20.
Loutzenhiser, K,
and
Loutzenhiser R.
Angiotensin II-induced Ca2+ influx in renal afferent and efferent arterioles: differing roles of voltage-gated and store-operated Ca2+ entry.
Circ Res
87:
551-557,
2000
21.
Macfarlane, SR,
Seatter MJ,
Kanke T,
Hunter GD,
and
Plevin R.
Proteinase-activated receptors.
Pharmacol Rev
53:
245-282,
2001
22.
Mirza, H,
Yatsula V,
and
Bahou WF.
The proteinase activated receptor-2 (PAR-2) mediates mitogenic responses in human vascular endothelial cells.
J Clin Invest
97:
1705-1714,
1996
23.
Moffatt, JD,
and
Cocks TM.
Endothelium-dependent and -independent responses to protease-activated receptor-2 (PAR-2) activation in mouse isolated renal arteries.
Br J Pharmacol
125:
591-594,
1998[Abstract].
24.
Molino, M,
Barnathan ES,
Numerof R,
Clark J,
Dreyer M,
Cumashi A,
Hoxie JA,
Schecter N,
Woolkalis M,
and
Brass LF.
Interactions of mast cell tryptase with thrombin receptors and PAR-2.
J Biol Chem
272:
4043-4049,
1997
25.
Molino, M,
Raghunath PN,
Kuo A,
Ahuja M,
Hoxie JA,
Brass LF,
and
Barnathan ES.
Differential expression of functional protease-activated receptor-2 (PAR-2) in human vascular smooth muscle cells.
Arterioscler Thromb Vasc Biol
18:
825-832,
1998
26.
Nystedt, S,
Emilsson K,
Wahlestedt C,
and
Sundelin J.
Molecular cloning of a potential proteinase-activated receptor.
Proc Natl Acad Sci USA
91:
9208-9212,
1994
27.
Nystedt, S,
Ramakrishnan V,
and
Sundelin J.
The proteinase-activated receptor 2 is induced by inflammatory mediators in human endothelial cells: comparison with the thrombin receptor.
J Biol Chem
271:
14910-14915,
1996
28.
Reslerova, M,
and
Loutzenhiser R.
Divergent mechanisms of ATP-sensitive K+ channel-induced vasodilation in renal afferent and efferent arterioles: evidence of L-type Ca2+ channel-dependent and -independent action of pinacidil.
Circ Res
77:
1114-1120,
1995
29.
Roberts, IS,
and
Brenchley PE.
Mast cells: the forgotten cells of renal fibrosis.
J Clin Pathol
53:
858-862,
2000
30.
Roy, SS,
Saifeddine M,
Loutzenhiser R,
Triggle CR,
and
Hollenberg MD.
Dual endothelium-dependent vascular activities of proteinase-activated receptor-2-activating peptides: evidence for receptor heterogeneity.
Br J Pharmacol
123:
1434-1440,
1998[Abstract].
31.
Saifeddine, M,
Al-Ani B,
Cheng C,
Wang L,
and
Hollenberg MD.
Rat proteinase-activated receptor-2 (PAR-2): cDNA sequence and activity of receptor-derived peptide in gastric and vascular tissue.
Br J Pharmacol
118:
521-530,
1996[Abstract].
32.
Saifeddine, M,
Roy SS,
Al-Ani B,
Triggle CR,
and
Hollenberg MD.
Endothelium-dependent contractile actions of proteinase-activated receptor-2-activating peptides in human umbilical vein: release of a contracting factor via a novel receptor.
Br J Pharmacol
125:
1445-1454,
1998[Abstract].
33.
Trottier, G,
Triggle CR,
O'Neill SK,
and
Loutzenhiser R.
Cyclic GMP-dependent and cyclic GMP-independent actions of nitric oxide on the renal afferent arteriole.
Br J Pharmacol
125:
563-569,
1998[Abstract].
34.
Vu, TK,
Hung DT,
Wheaton VI,
and
Coughlin SR.
Molecular cloning of a functional thrombin receptor reveals a novel proteolytic mechanism of receptor activation.
Cell
64:
1057-1068,
1991[ISI][Medline].
35.
Wang, X,
and
Loutzenhiser R.
Determinants of the renal microvascular response to acetylcholine: afferent and efferent arteriolar actions of EDHF.
Am J Physiol Renal Physiol
282:
F124-F132,
2002
36.
Xu, WF,
Anderson H,
Whitmore TE,
Presnell SR,
Yee DP,
Ching A,
Gilbert T,
Davie EW,
and
Foster DC.
Cloning and characterization of human protease-activated receptor 4.
Proc Natl Acad Sci USA
95:
6642-6646,
1998