The cytoprotective effect of biglycan core protein involves Toll-like receptor 4 signaling in cardiomyocytes. (October 2016)

• Record Type: Journal Article
• Authors: Gáspár, Renáta; Pipicz, Márton; Hawchar, Fatime; Kovács, Dávid; Djirackor, Luna; Görbe, Anikó; Varga, Zoltán V.; Kiricsi, Mónika; Petrovski, Goran; Gácser, Attila; Csonka, Csaba; Csont, Tamás
• Is Part Of: Journal of molecular and cellular cardiology. Volume 99(2016:Oct.)
• Page Start: 138
• Page End: 150
• Publication Date: 2016-10
• Subjects: TLR4 Toll-like receptor 4 -- SI/R simulated ischemia/reperfusion injury -- rhBGNc recombinant human biglycan core protein -- GAG glycosaminoglycan -- TGFβ transforming growth factor-beta -- BSA bovine serum albumin -- D-PBS Dulbecco's phosphate-buffered saline -- DHE dihydroethidium -- L-NAME Nω-Nitro-l-arginine methyl ester hydrochloride -- FBS fetal bovine serum -- DMEM Dulbecco's modified eagle medium -- RIPA radioimmunoprecipitation assay buffer -- STAT3 signal transducer and activator of transcription 3 -- ERK1/2 extracellular signal regulated protein kinase 1/2 -- GAPDH glyceraldehyde 3-phosphate dehydrogenase -- HRP horseradish peroxidase -- IRAK-1/4 interleukin-1 receptor-associated kinase 1/4 -- RISK reperfusion injury salvage kinase -- SAFE survival activating factor enhancement -- Akt protein kinase B -- NO nitric oxide -- BrdU 5′-bromo-2′-deoxiuridine -- RT room temperature -- ESR electron spin resonance spectroscopy; JUN N-terminal kinase -- Mitogen activated protein kinase -- Nitric oxide -- Protein kinase B -- Proteoglycan; Cardiology -- Periodicals; Heart Diseases -- Periodicals; Molecular Biology -- Periodicals; Cardiologie -- Périodiques; Cardiology; Electronic journals; Periodicals; 616.12
• DOI: 10.1016/j.yjmcc.2016.08.006
• Languages: English
• ISSNs: 0022-2828

Abstract

Abstract: Aims: Exogenously administered biglycan (core protein with high-molecular weight glycosaminoglycan chains) has been shown to protect neonatal cardiomyocytes against simulated ischemia/reperfusion injury (SI/R), however, the mechanism of action is not clear. In this study we aimed to investigate, which structural component of biglycan is responsible for its cardiocytoprotective effect and to further explore the molecular mechanisms involved in the cytoprotection. Methods and results: A pilot study was conducted to demonstrate that both native (glycanated) and deglycanated biglycan can attenuate cell death induced by SI/R in a dose-dependent manner in primary neonatal cardiomyocytes isolated from Wistar rats. In separate experiments, we have shown that similarly to glycanated biglycan, recombinant human biglycan core protein (rhBGNc) protects cardiomyocytes against SI/R injury. In contrast, the glycosaminoglycan component dermatan sulfate had no significant effect on cell viability, while chondroitin sulfate further enhanced cell death induced by SI/R. Treatment of cardiomyocytes with rhBGNc reverses the effect of SI/R upon markers of necrosis, apoptosis, mitochondrial membrane potential, and autophagy. We have also shown that pharmacological blockade of Toll-like receptor 4 (TLR4) signaling or its downstream mediators (IRAK1/4, ERK, JNK and p38 MAP kinases) abolished the cytoprotective effect of rhBGNc against SI/R injury. Pretreatment of cardiomyocytes with rhBGNc for 20 h resulted in increased Akt phosphorylation and NO production without having significant effect on phosphorylation of ERK1/2, STAT3, and on the production of superoxide. Treatment over 10 min and 1 h with rhBGNc increased ERK1 phosphorylation, while the SI/R-induced increase in superoxide production was attenuated by rhBGNc. Blockade of NO synthesis also prevented the cardiocytoprotective effect of rhBGNc. Conclusions: The core protein of exogenous biglycan protects myocardial cells from SI/R injury via TLR4-mediated mechanisms involving activation of ERK, JNK and p38 MAP kinases and increased NO production. The cytoprotective effect of rhBGNc is due to modulation of SI/R-induced changes in necrosis, apoptosis and autophagy. Highlights: Biglycan core protein (rhBGNc) protects cardiomyocytes from SI/R injury. RhBGNc modulates the effects of SI/R upon necrosis, apoptosis, and autophagy. The cardiocytoprotective effect of rhBGNc involves TLR4 signaling. Inhibition of ERK, JNK and p38 MAP kinases abolishes cytoprotection by rhBGNc. RhBGNc increases NO, activates Akt, and decreases superoxide induced by SI/R.