Ruduwaan Salie1,2, Aisha Khlani Hassan Alsalhin3, Erna Marais3, Amanda Lochner3. 1. Biomedical Research and Innovation Platform, South African Medical Research Council, Building D, Medicina, Francie van Zijl Drive, Parow Valley, Cape Town, Western Cape, South Africa. ruduwaan.salie@mrc.ac.za. 2. Faculty of Medicine and Health Sciences, Division of Medical Physiology, University of Stellenbosch, PO Box 19063, Cape Town, South Africa. ruduwaan.salie@mrc.ac.za. 3. Faculty of Medicine and Health Sciences, Division of Medical Physiology, University of Stellenbosch, PO Box 19063, Cape Town, South Africa.
Abstract
The β3-AR (beta3-adrenergic receptor) is resistant to short-term agonist-promoted desensitization and delivers a constant intracellular signal, making this receptor a potential target in acute myocardial infarction (AMI). AIM: To investigate whether selective modulation of β3-AR prior to or during ischemia and/or reperfusion may be cardioprotective. METHODS: Isolated perfused rat hearts were exposed to 35-min regional ischemia (RI) and 60-min reperfusion. The β3-AR agonist (BRL37344, 1 μM) or antagonist (SR59230A, 0.1 μM) was applied: (i) before RI (PreT) or (ii) last 10 min of RI (PerT) or (iii) onset of reperfusion (PostT) or (iv) during both PerT+PostT. Nitric oxide (NO) involvement was assessed, using the NOS inhibitor, L-NAME (50 μM). Endpoints were functional recovery, infarct size (IS), cGMP levels, and Western blot analysis of eNOS, ERKp44/p42, PKB/Akt, and glycogen synthase kinase-3β (GSK-3β). RESULTS: Selective treatment with BRL significantly reduced IS. L-NAME abolished BRL-mediated cardioprotection. BRL (PreT) and BRL (PerT) significantly increased cGMP levels (which were reduced by L-NAME) and PKB/Akt phosphorylation. BRL (PostT) produced significantly increased cGMP levels, PKB/Akt, and ERKp44/p42 phosphorylation. BRL (PerT+PostT) caused significant eNOS, PKB/Akt, ERKp44/p42, and GSK-3β phosphorylation. CONCLUSION: β3-AR activation by BRL37344 induced significant cardioprotection regardless of the experimental protocol. However, the pattern of intracellular signaling with each BRL treatment differed to some degree and suggests the involvement of cGMP, eNOS, ERK, GSK-3β, and particularly PKB/Akt activation. The data also suggest that clinical application of β3-AR stimulation should preferably be incorporated during late ischemia or/and early reperfusion.
The β3-AR (beta3-adrenergic receptor) is resistant to short-term agonist-promoted desensitization and delivers a constant intracellular signal, making this receptor a potential target in acute myocardial infarction (AMI). AIM: To investigate whether selective modulation of β3-AR prior to or during ischemia and/or reperfusion may be cardioprotective. METHODS: Isolated perfused rat hearts were exposed to 35-min regional ischemia (RI) and 60-min reperfusion. The β3-AR agonist (BRL37344, 1 μM) or antagonist (SR59230A, 0.1 μM) was applied: (i) before RI (PreT) or (ii) last 10 min of RI (PerT) or (iii) onset of reperfusion (PostT) or (iv) during both PerT+PostT. Nitric oxide (NO) involvement was assessed, using the NOS inhibitor, L-NAME (50 μM). Endpoints were functional recovery, infarct size (IS), cGMP levels, and Western blot analysis of eNOS, ERKp44/p42, PKB/Akt, and glycogen synthase kinase-3β (GSK-3β). RESULTS: Selective treatment with BRL significantly reduced IS. L-NAME abolished BRL-mediated cardioprotection. BRL (PreT) and BRL (PerT) significantly increased cGMP levels (which were reduced by L-NAME) and PKB/Akt phosphorylation. BRL (PostT) produced significantly increased cGMP levels, PKB/Akt, and ERKp44/p42 phosphorylation. BRL (PerT+PostT) caused significant eNOS, PKB/Akt, ERKp44/p42, and GSK-3β phosphorylation. CONCLUSION: β3-AR activation by BRL37344 induced significant cardioprotection regardless of the experimental protocol. However, the pattern of intracellular signaling with each BRL treatment differed to some degree and suggests the involvement of cGMP, eNOS, ERK, GSK-3β, and particularly PKB/Akt activation. The data also suggest that clinical application of β3-AR stimulation should preferably be incorporated during late ischemia or/and early reperfusion.
Authors: Thomas Dupas; Thomas Pelé; Justine Dhot; Mélanie Burban; Antoine Persello; Virginie Aillerie; Angélique Erraud; Angela Tesse; David Stevant; Angélique Blangy-Letheule; Céline Menguy; Vincent Sauzeau; Michel De Waard; Bertrand Rozec; Chantal Gauthier; Benjamin Lauzier Journal: Oxid Med Cell Longev Date: 2022-05-18 Impact factor: 7.310