title: Multiple factors from bradykinin-challenged astrocytes contribute to the neuronal apoptosis: involvement of astroglial ROS, MMP-9, and HO-1/CO system.
abstract: Bradykinin (BK) has been shown to induce the expression of several inflammatory mediators, including reactive oxygen species (ROS) and matrix metalloproteinases (MMPs), in brain astrocytes. These mediators may contribute to neuronal dysfunction and death in various neurological disorders. However, the effects of multiple inflammatory mediators released from BK-challenged astrocytes on neuronal cells remain unclear. Here, we found that multiple factors were released from brain astrocytes (RBA-1) exposed to BK in the conditioned culture media (BK-CM), including ROS, MMP-9, and heme oxygenase-1 (HO-1)/carbon monoxide (CO), leading to neuronal cell (SK-N-SH) death. Exposure of SK-N-SH cells to BK-CM or H2O2 reduced cell viability and induced cell apoptosis which were attenuated by N-acetyl cysteine, indicating a role of ROS in these responses. The effect of BK-CM on cell viability and cell apoptosis was also reversed by immunoprecipitation of BK-CM with anti-MMP-9 antibody (MMP-9-IP-CM) or MMP2/9 inhibitor, suggesting the involvement of MMP-9 in BK-CM-mediated responses. Astroglial HO-1/CO in BK-CM induced cell apoptosis and reduced cell viability which was reversed by hemoglobin. Consistently, the involvement of CO in these cellular responses was revealed by incubation with a CO donor CO-RM2 which was reversed by hemoglobin. The role of HO-1 in BK-CM-induced responses was confirmed by overexpression of HO-1 in SK-N-SH infected with Adv-HO-1. BK-CM-induced cell apoptosis was due to the activation of caspase-3 and cleavage of PARP. Together, we demonstrate that BK-induced several neurotoxic factors, including ROS, MMP-9, and CO released from astrocytes, may induce neuronal death through a caspase-3-dependent apoptotic pathway.
authors: Department of Physiology and Pharmacology and Health Aging Research Center, College of Medicine, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-San, Tao-Yuan, Taiwan. chuenmao@mail.cgu.edu.tw
authors: Chuen-Mao
authors: CM
authors: Yang
authors: Hsi-Lung
authors: HL
authors: Hsieh
authors: Chih-Chung
authors: CC
authors: Lin
authors: Ruey-Horng
authors: RH
authors: Shih
authors: Pei-Ling
authors: PL
authors: Chi
authors: Shin-Ei
authors: SE
authors: Cheng
authors: Li-Der
authors: LD
authors: Hsiao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001920:Bradykinin / Q000494:pharmacology*; D002248:Carbon Monoxide / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D051547:Heme Oxygenase-1 / Q000096:biosynthesis / Q000378:metabolism*; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D017077:Culture Media, Conditioned; D017382:Reactive Oxygen Species; D002248:Carbon Monoxide; D051547:Heme Oxygenase-1; D053148:Caspase 3; D020780:Matrix Metalloproteinase 9; D001920:Bradykinin