scholarly journals Role of the ROS-JNK Signaling Pathway in Hypoxia-Induced Atrial Fibrotic Responses in HL-1 Cardiomyocytes

2021 ◽  
Vol 22 (6) ◽  
pp. 3249
Author(s):  
Chin-Feng Tsai ◽  
Shun-Fa Yang ◽  
Chien-Hsien Lo ◽  
Hsiao-Ju Chu ◽  
Kwo-Chang Ueng
Keyword(s):  
Atrial Fibrillation ◽  
Signaling Pathway ◽  
Transforming Growth Factor ◽  
Nuclear Translocation ◽  
Dominant Negative ◽  
Jnk Signaling ◽  
Marker Proteins ◽  
Jnk Signaling Pathway ◽  
Pre Treatment ◽  
Tgf Β1

By promoting atrial structural remodeling, atrial hypoxia contributes to the development of the atrial fibrillation substrate. Our study aimed to investigate the modulatory effect of hypoxia on profibrotic activity in cultured HL-1 cardiomyocytes and explore the possible signaling transduction mechanisms of profibrotic activity in vitro. Hypoxia (1% O2) significantly and time-dependently increased the expression of hypoxia-inducible factor (HIF)-1α and fibrotic marker proteins collagen I and III (COL1A and COL3A), transforming growth factor (TGF)-β1 and α-smooth muscle actin (SMA). Western blot or immunohistochemistry analysis showed that hypoxia-induced increase in COL1A and COL3A was significantly attenuated by the addition of SP600125 (a specific c-Jun N-terminal kinase [JNK] inhibitor) or expression of dominant-negative JNK before hypoxia treatment. The inhibition of hypoxia-activated phosphorylation of JNK signal components (JNK, MKK4, nuclear c-Jun and ATF-2) by pre-treatment with SP600125 could suppress hypoxia-stimulated HIF-1α upregulation and fibrotic marker proteins expression. Hypoxia significantly increased reactive oxygen species (ROS) production in cultured HL-1 atrial cells. Pre-treatment with N-acetylcysteine significantly abrogated the expression of nuclear HIF-1α, JNK transduction components and fibrotic marker proteins. Taken together, these findings indicated that the hypoxia-induced atrial profibrotic response occurs mainly via the ROS/JNK pathway, its downstream upregulation of HIF-1α and c-Jun/ATF2 phosphorylation and nuclear translocation to up-regulate the expression of fibrosis-related proteins (COL1A, COL3A, TGF-β1 and α-SMA). Our result suggests that suppression of ROS/JNK signaling pathway is a critical mechanism for developing a novel therapeutic strategy against atrial fibrillation.

scholarly journals TAK1 Participates in c-Jun N-Terminal Kinase Signaling during Drosophila Development

2000 ◽  
Vol 20 (9) ◽  
pp. 3015-3026 ◽  
Author(s):  
Yoshihiro Takatsu ◽  
Makoto Nakamura ◽  
Mark Stapleton ◽  
Maria C. Danos ◽  
Kunihiro Matsumoto ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Transforming Growth Factor ◽  
Cultured Cells ◽  
Transforming Growth Factor Β ◽  
Kinase Domain ◽  
Dominant Negative ◽  
Jnk Signaling ◽  
Amino Terminal ◽  
Jnk Signaling Pathway

ABSTRACT Transforming growth factor β (TGF-β)-activated kinase 1 (TAK1) is a member of the MAPKKK superfamily and has been characterized as a component of the TGF-β/bone morphogenetic protein signaling pathway. TAK1 function has been extensively studied in cultured cells, but its in vivo function is not fully understood. In this study, we isolated aDrosophila homolog of TAK1 (dTAK1) which contains an extensively conserved NH2-terminal kinase domain and a partially conserved COOH-terminal domain. To learn about possible endogenous roles of TAK1 during animal development, we generated transgenic flies which express dTAK1 or the mouseTAK1 (mTAK1) gene in the fly visual system. Ectopic activation of TAK1 signaling leads to a small eye phenotype, and genetic analysis reveals that this phenotype is a result of ectopically induced apoptosis. Genetic and biochemical analyses also indicate that the c-Jun amino-terminal kinase (JNK) signaling pathway is specifically activated by TAK1 signaling. Expression of a dominant negative form of dTAK during embryonic development resulted in various embryonic cuticle defects including dorsal open phenotypes. Our results strongly suggest that in Drosophila melanogaster, TAK1 functions as a MAPKKK in the JNK signaling pathway and participates in such diverse roles as control of cell shape and regulation of apoptosis.

scholarly journals Store-operated calcium entry suppressed the TGF-β1/Smad3 signaling pathway in glomerular mesangial cells

2017 ◽  
Vol 313 (3) ◽  
pp. F729-F739 ◽  
Author(s):  
Sarika Chaudhari ◽  
Weizu Li ◽  
Yanxia Wang ◽  
Hui Jiang ◽  
Yuhong Ma ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Transforming Growth Factor ◽  
Nuclear Translocation ◽  
Mesangial Cells ◽  
Underlying Mechanism ◽  
Glomerular Mesangial Cells ◽  
Critical Pathway ◽  
Smad3 Phosphorylation ◽  
Tgf Β1

Our previous study demonstrated that the abundance of extracellular matrix proteins was suppressed by store-operated Ca2+entry (SOCE) in mesangial cells (MCs). The present study was conducted to investigate the underlying mechanism focused on the transforming growth factor-β1 (TGF-β1)/Smad3 pathway, a critical pathway for ECM expansion in diabetic kidneys. We hypothesized that SOCE suppressed ECM protein expression by inhibiting this pathway in MCs. In cultured human MCs, we observed that TGF-β1 (5 ng/ml for 15 h) significantly increased Smad3 phosphorylation, as evaluated by immunoblot. However, this response was markedly inhibited by thapsigargin (1 µM), a classical activator of store-operated Ca2+channels. Consistently, both immunocytochemistry and immunoblot showed that TGF-β1 significantly increased nuclear translocation of Smad3, which was prevented by pretreatment with thapsigargin. Importantly, the thapsigargin effect was reversed by lanthanum (La3+; 5 µM) and GSK-7975A (10 µM), both of which are selective blockers of store-operated Ca2+channels. Furthermore, knockdown of Orai1, the pore-forming subunit of the store-operated Ca2+channels, significantly augmented TGF-β1-induced Smad3 phosphorylation. Overexpression of Orai1 augmented the inhibitory effect of thapsigargin on TGF-β1-induced phosphorylation of Smad3. In agreement with the data from cultured MCs, in vivo knockdown of Orai1 specific to MCs using a targeted nanoparticle small interfering RNA delivery system resulted in a marked increase in abundance of phosphorylated Smad3 and in nuclear translocation of Smad3 in the glomerulus of mice. Taken together, our results indicate that SOCE in MCs negatively regulates the TGF-β1/Smad3 signaling pathway.

scholarly journals The cJun N-terminal kinase (JNK) signaling pathway mediates induction of urokinase-type plasminogen activator (uPA) by the alkylating agent MNNG

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1415-1424 ◽  
Author(s):  
Maribel Parra ◽  
Frederic Lluı́s ◽  
Francesc Miralles ◽  
Carme Caelles ◽  
Pura Muñoz-Cánoves
Keyword(s):  
Dna Repair ◽  
Plasminogen Activator ◽  
Signaling Pathway ◽  
Alkylating Agent ◽  
Dominant Negative ◽  
Environmental Carcinogen ◽  
Jnk Signaling ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Jnk Signaling Pathway

The monofunctional alkylating agent N-methyl-N-nitro-N-nitrosoguanidine (MNNG) is a widespread environmental carcinogen that causes DNA lesions, leading to cell death. However, MNNG can also trigger a cell-protective response by inducing the expression of DNA repair/transcription-related genes. We demonstrate that the urokinase-type plasminogen activator (uPA) gene product, a broad spectrum extracellular protease to which no DNA repair function has been assigned, is transcriptionally induced by MNNG in C2C12 and NIH3T3 cells. This induction required an AP1-enhancer element located at −2.4 kilobase (kb), because it was abrogated by deletion of this site. MNNG was found to induce the activation of JNK/SAPK and p38 mitogen-activated protein kinases (MAPKs). Accordingly, we attempted to assess the contribution of each of these MNNG-inducible MAPKs to uPA gene induction by this alkylating agent. Coexpression of dominant negative versions of kinases of the JNK pathway, such as catalytically inactive forms of MEKK1, MKK7, and JNKK, and of cytoplasmic JNK-inhibitor JIP-1, as well as treatment of cells with curcumin (which blocks JNK activation by MNNG), inhibited MNNG-induced uPA transcriptional activity. In contrast, neither dominant negative MKK6 nor SB203580, which specifically inhibit p38 MAP kinase activation, abrogated the MNNG-induced effect. Taken together, our results show that the JNK signaling pathway links external MNNG stimulation and AP1-dependent uPA gene expression, providing the first functional dissection of a transcription-coupled signal transduction pathway for MNNG.

scholarly journals The cJun N-terminal kinase (JNK) signaling pathway mediates induction of urokinase-type plasminogen activator (uPA) by the alkylating agent MNNG

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1415-1424 ◽  
Author(s):  
Maribel Parra ◽  
Frederic Lluı́s ◽  
Francesc Miralles ◽  
Carme Caelles ◽  
Pura Muñoz-Cánoves
Keyword(s):  
Dna Repair ◽  
Plasminogen Activator ◽  
Signaling Pathway ◽  
Alkylating Agent ◽  
Dominant Negative ◽  
Environmental Carcinogen ◽  
Jnk Signaling ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator ◽  
Jnk Signaling Pathway

Abstract The monofunctional alkylating agent N-methyl-N-nitro-N-nitrosoguanidine (MNNG) is a widespread environmental carcinogen that causes DNA lesions, leading to cell death. However, MNNG can also trigger a cell-protective response by inducing the expression of DNA repair/transcription-related genes. We demonstrate that the urokinase-type plasminogen activator (uPA) gene product, a broad spectrum extracellular protease to which no DNA repair function has been assigned, is transcriptionally induced by MNNG in C2C12 and NIH3T3 cells. This induction required an AP1-enhancer element located at −2.4 kilobase (kb), because it was abrogated by deletion of this site. MNNG was found to induce the activation of JNK/SAPK and p38 mitogen-activated protein kinases (MAPKs). Accordingly, we attempted to assess the contribution of each of these MNNG-inducible MAPKs to uPA gene induction by this alkylating agent. Coexpression of dominant negative versions of kinases of the JNK pathway, such as catalytically inactive forms of MEKK1, MKK7, and JNKK, and of cytoplasmic JNK-inhibitor JIP-1, as well as treatment of cells with curcumin (which blocks JNK activation by MNNG), inhibited MNNG-induced uPA transcriptional activity. In contrast, neither dominant negative MKK6 nor SB203580, which specifically inhibit p38 MAP kinase activation, abrogated the MNNG-induced effect. Taken together, our results show that the JNK signaling pathway links external MNNG stimulation and AP1-dependent uPA gene expression, providing the first functional dissection of a transcription-coupled signal transduction pathway for MNNG.

Sign in / Sign up

Export Citation Format

Share Document