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Pierre Sirois
Institute of Pharmacology of Sherbrooke
Medical School
University of Sherbrooke
Sherbrooke
PQ, Canada J1H 5N4
Pierre.Sirois@USherbrooke.ca
Dr. Pierre Sirois, B.A. ,B.Sc.,M.Sc.,Ph.D.
Professor Sirois received his training from Laval, Sherbrooke, Toronto and London (UK) Universities. He has been professor of pharmacology for 30 years and chair of the department of pharmacology of Sherbrooke Medical School for 12 years. He created the Institute of Pharmacology of Sherbrooke as well as two biotech companies: IPS Pharma and IPS Therapeutique. His research is focused on the pathophysiology of inflammatory reactions. He played a major role in the discovery of leukotrienes. He is the author of 330 publications and 530 abstracts and delivered more than 300 conferences in various countries. He was also the recipient of many awards and grants.

Journal articles

2009
 
DOI   
PMID 
Li Xiao, Juan-Sebastian Saldivar, Cuilan Zhou, Chengli Chen, Jia Zhang, Pierre Sirois, Kai Li (2009)  The updated concept of genome and its implications in biotechnological research and molecular diagnostics.   Mol Biotechnol 41: 2. 152-156 Feb  
Abstract: We propose a short definition of GENOME: The full complement of genetic materials possessed by an intracellular parasite, a cell, or an organism. Accordingly, the human genome is the entire complement of inherited genetic materials possessed by an individual person, or possessed by a cell in an individual person. For higher species, the genomic makeup includes DNA in the nucleus and in the organelles regardless of the number of chromosomes and the homoplasmic or heteroplasmic status of the mitochondrial or chloroplastic DNA. Practically, GENOME can be referred to at the molecular, cellular, individual, and species levels, which has various implications in biotechnological research and molecular diagnostics.
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2008
 
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PMID 
L Xiao, J Zhang, Y F Yin, C L Chen, Kai Li, A Chang, P Sirois (2008)  Molecular diagnosis of HIV and relevant novel technologies in mutation analysis.   Biotechnol Adv 26: 5. 389-397 Sep/Oct  
Abstract: HIV infection is one of the major threats to human health due to the lack of relevant vaccine and drugs to cure AIDS. Its early diagnosis is thus important in controlling HIV transmission. Molecular diagnosis of HIV can be performed qualitatively and quantitatively. Currently, molecular diagnosis of HIV infection is only used as a complementary diagnosis although viral load test is used to monitor disease progression and responsiveness to antiviral therapy. To optimize HIV assays, a variety of technological advances, such as the introduction of dUTP/UNG system, real-time detection platform, and coupling of more than one enzyme in molecular identification, have been integrated into new methods. With the development of more reliable HIV assays in the future, the molecular diagnosis of HIV is expected to be accepted as one of the standards in determining whether there is a HIV infection in resource-rich laboratories, which will play a crucial role in reducing HIV transmission.
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2007
 
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PMID 
Martin Richter, Solange Cloutier, Pierre Sirois (2007)  Endothelin, PAF and thromboxane A2 in allergic pulmonary hyperreactivity in mice.   Prostaglandins Leukot Essent Fatty Acids 76: 5. 299-308 May  
Abstract: The role of endothelin, PAF and thromboxane A2 in airway hyperreactivity (AHR) to carbachol induced by ovalbumin sensitization and challenge in Balb/c mice was investigated. Ovalbumin sensitization and challenge induced significant AHR to carbachol in actively sensitized and challenged mice. Treatment of these mice with the PAF antagonist CV-3988 (10 microg kg(-1), i.v.) completely abolished OVA-induced AHR to carbachol. Treatment of sensitized mice with the TxA2 antagonist L-654,664 (1 mg kg(-1), i.v.) partially blocked the induction of AHR in OVA-challenged mice. The intranasal administration of 50 pmol of the ET(A) receptor antagonist BQ-123 had no effect on the PIP but produced a significant reduction at the dose of 100 pmol. The intravenous administration of BQ-123 (100 pmol) reduced the PIP only at the highest doses of carbachol. The ET(B) receptor antagonist BQ-788 administered either via the intranasal or intravenous route had no effect on the PIP at the dose of 100 pmol. Naïve mice treated with either U-44069 (25 or 100 microg kg(-1), i.v.), endothelin-1 (100 pmol, intranasally) or the ET(B) receptor agonist IRL-1620 (100 pmol, intranasally) showed a marked increase in airway reactivity to carbachol. These results suggest an important role for endothelin, PAF and thromboxane A2 in AHR in mice actively sensitized and challenged with ovalbumin.
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PMID 
Monica C Toffoli, Bichoy H Gabra, Catarina F P Teixeira, Pierre Sirois, Sonia Jancar (2007)  Endothelins mediate neutrophil activation, ProMMP-9 release and endothelial cell detachment.   Inflammation 30: 1-2. 28-37 Apr  
Abstract: Neutrophils isolated from human peripheral blood added to a monolayer of human endothelial cells (ECV-304 cell line) stimulated with LPS (100 ng ml(-1)) resulted in: (a) neutrophil activation, measured by spreading and release of leukotriene B(4) (LTB(4)); (b) neutrophil degranulation, measured by release of matrix pro-metalloproteinase-9 (proMMP-9) and (c) loss of the monolayer integrity due to detachment of the endothelial cells. Stimulation of endothelial cells with tumor necrosis factor-alpha (TNF-alpha 10 ng ml(-1)) or interleukin-1 (IL-1; 10 ng ml(-1)) induced a similar dose-dependent increase in the neutrophil activation and endothelial cell detachment. Pre-treatment of LPS-activated ECV-304 cells with [Phe22]BigET-1(19-37) (10(-9) M; an inhibitor of endothelin converting enzyme (ECE)) or addition of BQ-123 (10(-6) M; a selective endothelin A (ET(A)) receptor antagonist) to the co-cultures, significantly reduced neutrophil spreading (50-70% inhibition) as well as the levels of LTB(4) (70-100% inhibition) and proMMP-9 (40-50% inhibition) in the co-culture supernatants. In addition, the detachment of endothelial cells was also reduced (60-75% inhibition). Moreover, the exogenous addition of ET-1 (10(-9) M) to neutrophil suspensions induced neutrophil spreading and release of LTB(4) and proMMP-9. Taken together, these findings indicate that neutrophils added to stimulated endothelial cells in the co-culture system employed in this study, get activated by products of these cells and degranulate. In parallel, the detachment of endothelial cell monolayer from the culture plates, possibly by the action of neutrophil granule-derived gelatinases, is observed. Endothelins (ETs) produced by the endothelial cells are suggested to play an essential role in these phenomena.
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Quan Yang, Bruno Battistini, Stéphane Pelletier, Pierre Sirois (2007)  Inhibition of basal and stimulated release of endothelin-1 from guinea pig tracheal epithelial cells in culture by beta 2-adrenoceptor agonists and cyclic AMP enhancers.   Inflammation 30: 5. 136-147 Oct  
Abstract: The effects of cyclic AMP-related compounds and beta adrenoceptor agonists on the basal and lipopolysaccharide (LPS)-stimulated release of endothelin-1 (ET-1) from guinea-pig tracheal epithelial cells (GPTEpCs) in culture were studied. Forskolin (a potent activator of adenylyl cyclase), 8-bromo-cyclic AMP (a cyclic AMP analogue), salbutamol and salmeterol (two beta 2-adrenoceptor agonists), were used to increase cyclic AMP levels. Cultured GPTEpCs released ET-1 continuously over a 24 h incubation period. The values reached 1,938 +/- 122 pg/mg of total cell proteins after 24 h. LPS (10 microg/ml) significantly stimulated the release of ET-1 by 1.6- to 1.8-fold, up to 1,262 +/- 56 pg/mg total cell proteins after an 8 h incubation period. Compound 8-bromo-cyclic AMP (10(-5), 10(-4) and 10(-3) M) reduced the basal release of ET-1 from GPTEpCs by up to 31% (P < 0.01) and the LPS stimulated release by up to 42% (P < 0.05), after an 8 h incubation period. Forskolin (10(-6), 10(-5) and 10(-4) M) also inhibited the basal release of ET-1 by up to 28% (P < 0.05) and LPS-stimulated release of ET-1 by up to 50% (P < 0.05), after an 8 h incubation period. At the concentration of 10(-5) M, forskolin increased cyclic AMP levels in GPTEpCs by 17-fold (P < 0.001) in the medium, 15 min after the beginning of the incubation. Salbutamol (10(-8) to 10(-6) M) had no effect on the basal production and release of ET-1 after 8 h. Conversely, this short acting beta 2-adrenoceptor agonist significantly reduced LPS-mediated increase of ET-1 production by up to 55% (P < 0.05) after an 8 h incubation period. Salmeterol (10(-9) M to 10(-5) M) inhibited basal and LPS-stimulated production and release of ET-1 after an 8 h incubation period (between 44 and 51%, P < 0.01). Both salbutamol and salmeterol (10(-6) M) increase cyclic AMP levels by five- and twofold, respectively (P < 0.05). In summary, these observations indicate that beta 2-adrenoceptor agonists or cyclic AMP enhancers can modulate both basal and more markedly, the enhanced production of ET-1 from LPS-activated guinea pig airway EpCs. In addition, these compounds increase cyclic AMP levels in the cells. It is suggested that there is a correlation between cyclic AMP increase and inhibition of ET-1 release by guinea pig airway EpCs. Since ET-1 production was shown to be elevated in asthmatic subjects and in patients suffering from other inflammatory lung disorders, the inhibition of its production by beta adrenoceptor agonists, such as salbutamol and salmeterol, could be added to their therapeutical benefits.
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Richardt G Landgraf, Daniela F Nossi, Pierre Sirois, Sonia Jancar (2007)  Prostaglandins, leukotrienes and PAF selectively modulate lymphocyte subset and eosinophil infiltration into the airways in a murine model of asthma.   Prostaglandins Leukot Essent Fatty Acids 77: 3-4. 163-172 Oct/Nov  
Abstract: The effects of inhibitors of prostaglandins synthesis, indomethacin and nimesulide, or of receptor antagonists of cysteinyl-leukotrienes, MK571 or of platelet activating factor (PAF), WEB2170, were studied on the infiltration of lymphocytes (Tgammadelta, NKT, CD4, CD8 and B cells) and eosinophils into the bronchoalveolar lavage fluid (BALF) in two mouse strains (C57Bl/6 and BALB/c) as well as on bronchial hyperreactivity and mucus production. It was found that indomethacin and nimesulide strongly reduced the number of all cell types analyzed in both mouse strains. MK571 did not affect Tgammadelta or CD4 lymphocytes but reduced the other populations. WEB2170 reduced all lymphocyte subpopulations in both mouse strains. Moreover, the relative numbers of the lymphocyte subsets in the airways and their response to PAF antagonist were strain-dependent. The intensity of bronchoconstriction and mucus production did not correlate with BALF cell types or numbers. The cysteinyl-leukotriene receptor antagonist inhibited eosinophil infiltration and bronchial hyperreactivity, without affecting the Tgammadelta cell subset. Since Tgammadelta cells play a major role in mucosa protection and resolution of lung inflammation, this would represent an additional benefit of cysteinyl-leukotrienes antagonism in asthma.
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DOI   
PMID 
Jia Zhang, Y O Wu, Li Xiao, Kai Li, L L Chen, P Sirois (2007)  Therapeutic potential of RNA interference against cellular targets of HIV infection.   Mol Biotechnol 37: 3. 225-236 Nov  
Abstract: RNA interference is not only very promising in identifying new targets for drug development, siRNA/shRNA themselves may be directly used as therapeutic agents. In inhibiting viral infections by RNA interference, both viral targets and cellular proteins have been evaluated. Most of the early studies in this field had chosen viral targets for RNA interference. However, recent efforts are mainly focusing on cellular proteins for RNA silencing due to the realization that a variety of viral responses substantially minimize siRNA effects. With the application of siRNA approaching, many new cellular targets relevant to HIV infection have been identified. The value of siRNA/shRNA in the treatment of AIDS is largely dependent on better understanding of the biology of HIV replication. Efforts in the identification of cellular processes with the employment of siRNA/shRNA have shed some new lights on our understanding of how HIV infection occurs. Furthermore, the relative specific effects and simplicity of design makes siRNA/shRNA themselves to be favorable drug leads.
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2006
 
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PMID 
P Daull, R Lepage, O Benrezzak, J Cayer, M Beaudoin, K Belleville, A Blouin, P Sirois, F Nantel, A Y Jeng, B Battistini (2006)  The first preclinical pharmacotoxicological safety assessment of CGS 35601, a triple vasopeptidase inhibitor, in chronically instrumented, conscious, and unrestrained spontaneously hypertensive rats.   Drug Chem Toxicol 29: 2. 183-202  
Abstract: CGS 35601 is a triple vasopeptidase inhibitor (VPI) of angiotensin-converting enzyme, neutral endopeptidase, and endothelin-converting enzyme-1 with respective IC50 values of 22, 2, and 55 nM. We characterized the safety profile and toxicity of escalating doses of CGS 35601 over a 20-day period in chronically instrumented, unrestrained, conscious, male, spontaneously hypertensive rats (SHR). Once instrumented with an arterial catheter, the SHR were placed in metabolic cages allowing daily assessment of hemodynamics and blood sampling for biochemical and hematological measurements. After a 7-day stabilization period, the SHR were divided into 2 groups: Gr. 1, (n = 13 to 18) receiving CGS 35601 at 0.01, 0.1, 1 and 5 mg kg(-1) day(-1) (continuous i.a. infusion) for 5 consecutive days/dose, followed by a 5-day washout; and Gr. 2, (n = 10) receiving vehicle (saline). The highest dose of CGS 35601 dose-dependently reduced MABP from 156 +/- 4 up to 94 +/- 5 mm Hg, whereas heart rate, metabolic, electrolytic, and hematological profiles, growth, diuresis, and renal activity were unaffected, and no hepatic or liver toxicities were observed. These results suggest that this novel triple VPI presents no safety concerns at this stage and may become of interest for the treatment of hypertension and other cardiovascular disorders. Long-term chronic experiments are needed to assess possible angioedema and increases in vascular permeability.
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PMID 
P Daull, A Blouin, M Beaudoin, S Gadbois, K Belleville, J Cayer, N Berthiaume, P Sirois, F Nantel, A Y Jeng, B Battistini (2006)  The hemodynamic and metabolic profiles of Zucker diabetic fatty rats treated with a single molecule triple vasopeptidase inhibitor, CGS 35601.   Exp Biol Med (Maywood) 231: 6. 824-829 Jun  
Abstract: CGS 35601 is a triple vasopeptidase inhibitor (VPI) of angiotensin converting enzyme (ACE), neutral endopeptidase (NEP), and endothelin (ET) converting enzyme-1 (ECE-1), with respective IC(50) values of 22, 2, and 55 nM. The aim of the present study was to establish the hemodynamic profile of Zucker diabetic fatty (Zdf)-Fatty rats, a high-fat diet gene-prone model developing spontaneous Type 2 diabetes (T2D) and the effects of CGS 35601. Male Zdf-Fatty (14 weeks, n = 17-23), Zdf-Lean (14 weeks, n = 8-10), and Wistar (14 weeks, n = 9-10) rats on distinct diets were implanted with a catheter in the left carotid and placed individually in a metabolic cage for 30 days. The hemodynamic profile and some metabolic biomarkers were assessed daily. After a 7-day stabilization period, the Zdf-Fatty rats were divided into two groups: Group 1, controls (n = 7-10) receiving vehicle-saline (250 microl/hr) and Group 2, (n = 10-13) receiving increasing doses of CGS 35601 (0.1, 1, and 5 mg/kg/day x 6 days each, intra-arterially) followed by a 5-day washout period. Mean arterial blood pressure (MABP) of young Zdf-Fatty rats was compared with age-matched Zdf-Lean and Wistar rats, which were found similar. MABP decreased by 5.9% (from baseline at 102 +/- 5 to 96 +/- 4 mmHg), 12.7% (to 89 +/- 6 mmHg) and 21.6% (to 80 +/- 4 mmHg), at 0.1, 1, and 5 mg/kg/day, respectively, in CGS 35601-treated Zdf-Fatty rats. Systolic and diastolic blood pressures were similarly reduced. The heart rate was not affected. Hyperglycemic status and insulin-resistance were not modulated by short-term treatment. CGS 35601 presented an excellent short-term safety profile. This novel molecule and class of VPI may be of interest for lowering vascular tone. Further long-term studies, once cardiovascular and renal complications have developed in this T2D rat model are warranted to define the efficacy of this class of VPI.
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PMID 
P Daull, A Blouin, K Belleville, M Beaudoin, D Arsenault, H Leonard, P Sirois, F Nantel, A Y Jeng, B Battistini (2006)  Triple VPI CGS 35601 reduces high blood pressure in low-renin, high-salt Dahl salt-sensitive rats.   Exp Biol Med (Maywood) 231: 6. 830-833 Jun  
Abstract: We previously reported that CGS 35601, a potent triple inhibitor of angiotensin-converting enzyme, neutral endopeptidase, and endothelin-converting enzyme 1, completely normalized mean arterial blood pressure (MABP) in 36-week-old spontaneously hypertensive rats, a normal renin model. The aim of the present study was to determine the effects of this triple vasopeptidase inhibitor (VPI) on the hemodynamic profile of instrumented, conscious, and unrestrained Dahl salt-sensitive (DSS) rats, a gene-prone, high-salt diet-induced low-renin hypertension model. Male DSS rats (mean weight [+/-SEM], 385 +/- 10 g) were fed a normal diet (Group 1) or a high-salt diet (Groups 2 and 3; 8% NaCl in food) for 6 weeks and then instrumented with a carotid catheter and placed individually in metabolic cages for 30 days. The hemodynamic, hematological, and biochemical profiles were assessed daily. Dose-dependent treatment started after a 7-day stabilization period in Groups 1 and 2 (vehicle dosage, 250 microl/hr) and Group 3 (CGS 35601 dosages of 0.1, 1, and 5 mg/kg/day for 6 days per dose by means of constant intra-arterial infusion), followed by a 5-day washout period. Two additional groups included normotensive Wistar rats (Group 4) and DSS rats that received a double high-salt solid (8% NaCl) and liquid (1% NaCl) diet (Group 5).The MABP in rats receiving CGS 35601 decreased in a dose-dependent fashion toward the baseline level observed in DSS rats receiving a normal diet. The heart rate was unaffected. The hemodynamic profile returned to normal during the washout period. This novel triple VPI is a potent and effective antihypertensive agent with a safe short-term profile that may be of interest for treating hypertension and other cardiovascular diseases. Other hypertensive rat models are being tested.
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