scholarly journals G protein pathway suppressor 2 enhanced the renal large-conductance Ca2+-activated potassium channel expression via inhibiting ERK1/2 signaling pathway

2018 ◽  
Vol 315 (3) ◽  
pp. F503-F511 ◽  
Author(s):  
Zhizhi Zhuang ◽  
Jia Xiao ◽  
Xinxin Chen ◽  
Xiaohan Hu ◽  
Ruidian Li ◽  
...  
Keyword(s):  
Protein Expression ◽  
Signaling Pathway ◽  
G Protein ◽  
Mapk Signaling ◽  
Bk Channels ◽  
Bk Channel ◽  
Mapk Signaling Pathway ◽  
Dependent Manner ◽  
Channel Activity ◽  
Open Probability

G protein pathway suppressor 2 (GPS2) is a multifunctional protein and transcriptional regulation factor that is involved in the G protein MAPK signaling pathway. It has been shown that the MAPK signaling pathway plays an important role in the regulation of renal large-conductance Ca2+-activated potassium (BK) channels. In this study, we investigated the effects of GPS2 on BK channel activity and protein expression. In human embryonic kidney (HEK) BK stably expressing cells transfected with either GPS2 or its vector control, a single-cell recording showed that GPS2 significantly increased BK channel activity ( NPo), increasing BK open probability ( Po), and channel number ( N) compared with the control. In Cos-7 cells and HEK 293 T cells, GPS2 overexpression significantly enhanced the total protein expression of BK in a dose-dependent manner. Knockdown of GPS2 expression significantly decreased BK protein expression, while increasing ERK1/2 phosphorylation. Knockdown of ERK1/2 expression reversed the GPS2 siRNA-mediated inhibition of BK protein expression in Cos-7 cells. Pretreatments of Cos-7 cells with either the lysosomal inhibitor bafilomycin A1 or the proteasomal inhibitor MG132 partially reversed the inhibitory effects of GPS2 siRNA on BK protein expression. In addition, feeding a high-potassium diet significantly increased both GPS2 and BK protein abundance in mice. These data suggest that GPS2 enhances BK channel activity and its protein expression by reducing ERK1/2 signaling-mediated degradation of the channel.

scholarly journals 14-3-3γ, a novel regulator of the large-conductance Ca2+-activated K+ channel

2020 ◽  
Vol 319 (1) ◽  
pp. F52-F62
Author(s):  
Shan Chen ◽  
Xiuyan Feng ◽  
Xinxin Chen ◽  
Zhizhi Zhuang ◽  
Jia Xiao ◽  
...  
Keyword(s):  
Protein Expression ◽  
Specific Inhibitor ◽  
Bk Channels ◽  
Bk Channel ◽  
K Channel ◽  
Channel Activity ◽  
Open Probability ◽  
Protein Ubiquitination ◽  
293 Cells

14-3-3γ is a small protein regulating its target proteins through binding to phosphorylated serine/threonine residues. Sequence analysis of large-conductance Ca2+-activated K+ (BK) channels revealed a putative 14-3-3 binding site in the COOH-terminal region. Our previous data showed that 14-3-3γ is widely expressed in the mouse kidney. Therefore, we hypothesized that 14-3-3γ has a novel role in the regulation of BK channel activity and protein expression. We used electrophysiology, Western blot analysis, and coimmunoprecipitation to examine the effects of 14-3-3γ on BK channels both in vitro and in vivo. We demonstrated the interaction of 14-3-3γ with BK α-subunits (BKα) by coimmunoprecipitation. In human embryonic kidney-293 cells stably expressing BKα, overexpression of 14-3-3γ significantly decreased BK channel activity and channel open probability. 14-3-3γ inhibited both total and cell surface BKα protein expression while enhancing ERK1/2 phosphorylation in Cos-7 cells cotransfected with flag-14-3-3γ and myc-BK. Knockdown of 14-3-3γ by siRNA transfection markedly increased BKα expression. Blockade of the ERK1/2 pathway by incubation with the MEK-specific inhibitor U0126 partially abolished 14-3-3γ-mediated inhibition of BK protein expression. Similarly, pretreatment of the lysosomal inhibitor bafilomycin A1 reversed the inhibitory effects of 14-3-3γ on BK protein expression. Furthermore, overexpression of 14-3-3γ significantly increased BK protein ubiquitination in embryonic kidney-293 cells stably expressing BKα. Additionally, 3 days of dietary K+ challenge reduced 14-3-3γ expression and ERK1/2 phosphorylation while enhancing renal BK protein expression and K+ excretion. These data suggest that 14-3-3γ modulates BK channel activity and protein expression through an ERK1/2-mediated ubiquitin-lysosomal pathway.

scholarly journals Large-conductance voltage- and Ca2+-activated K+ channel regulation by protein kinase C in guinea pig urinary bladder smooth muscle

2014 ◽  
Vol 306 (5) ◽  
pp. C460-C470 ◽  
Author(s):  
Kiril L. Hristov ◽  
Amy C. Smith ◽  
Shankar P. Parajuli ◽  
John Malysz ◽  
Georgi V. Petkov
Keyword(s):  
Smooth Muscle ◽  
Membrane Potential ◽  
Guinea Pig ◽  
Bk Channels ◽  
Bk Channel ◽  
K Channel ◽  
Channel Activity ◽  
Open Probability ◽  
Channel Regulation ◽  
Pkc Activation

Large-conductance voltage- and Ca2+-activated K+ (BK) channels are critical regulators of detrusor smooth muscle (DSM) excitability and contractility. PKC modulates the contraction of DSM and BK channel activity in non-DSM cells; however, the cellular mechanism regulating the PKC-BK channel interaction in DSM remains unknown. We provide a novel mechanistic insight into BK channel regulation by PKC in DSM. We used patch-clamp electrophysiology, live-cell Ca2+ imaging, and functional studies of DSM contractility to elucidate BK channel regulation by PKC at cellular and tissue levels. Voltage-clamp experiments showed that pharmacological activation of PKC with PMA inhibited the spontaneous transient BK currents in native freshly isolated guinea pig DSM cells. Current-clamp recordings revealed that PMA significantly depolarized DSM membrane potential and inhibited the spontaneous transient hyperpolarizations in DSM cells. The PMA inhibitory effects on DSM membrane potential were completely abolished by the selective BK channel inhibitor paxilline. Activation of PKC with PMA did not affect the amplitude of the voltage-step-induced whole cell steady-state BK current or the single BK channel open probability (recorded in cell-attached mode) upon inhibition of all major Ca2+ sources for BK channel activation with thapsigargin, ryanodine, and nifedipine. PKC activation with PMA elevated intracellular Ca2+ levels in DSM cells and increased spontaneous phasic and nerve-evoked contractions of DSM isolated strips. Our results support the concept that PKC activation leads to a reduction of BK channel activity in DSM via a Ca2+-dependent mechanism, thus increasing DSM contractility.

Micromolar Ca2+ from sparks activates Ca2+-sensitive K+ channels in rat cerebral artery smooth muscle

2001 ◽  
Vol 281 (6) ◽  
pp. C1769-C1775 ◽  
Author(s):  
Guillermo J. Pérez ◽  
Adrian D. Bonev ◽  
Mark T. Nelson
Keyword(s):  
Smooth Muscle ◽  
Laser Scanning ◽  
Cerebral Arteries ◽  
Bk Channels ◽  
Bk Channel ◽  
Hill Coefficient ◽  
Channel Activity ◽  
Acetoxymethyl Ester ◽  
Open Probability ◽  
Apparent Dissociation Constant

The goal of the present study was to test the hypothesis that local Ca2+ release events (Ca2+ sparks) deliver high local Ca2+concentration to activate nearby Ca2+-sensitive K+ (BK) channels in the cell membrane of arterial smooth muscle cells. Ca2+ sparks and BK channels were examined in isolated myocytes from rat cerebral arteries with laser scanning confocal microscopy and patch-clamp techniques. BK channels had an apparent dissociation constant for Ca2+ of 19 μM and a Hill coefficient of 2.9 at −40 mV. At near-physiological intracellular Ca2+ concentration ([Ca2+]i; 100 nM) and membrane potential (−40 mV), the open probability of a single BK channel was low (1.2 × 10−6). A Ca2+spark increased BK channel activity to 18. Assuming that 1–100% of the BK channels are activated by a single Ca2+ spark, BK channel activity increases 6 × 105-fold to 6 × 103-fold, which corresponds to ∼30 μM to 4 μM spark Ca2+ concentration. 1,2-bis(2-aminophenoxy)ethane- N,N,N′,N′-tetraacetic acid acetoxymethyl ester caused the disappearance of all Ca2+sparks while leaving the transient BK currents unchanged. Our results support the idea that Ca2+ spark sites are in close proximity to the BK channels and that local [Ca2+]i reaches micromolar levels to activate BK channels.

scholarly journals Aloesin Suppresses Cell Growth and Metastasis in Ovarian Cancer SKOV3 Cells through the Inhibition of the MAPK Signaling Pathway

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Li-qian Zhang ◽  
Rong-wei Lv ◽  
Xiang-dong Qu ◽  
Xian-jun Chen ◽  
Hong-sheng Lu ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cell Growth ◽  
Signaling Pathway ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Migration And Invasion ◽  
Therapeutic Drug ◽  
Dependent Manner ◽  
Skov3 Cells

Aloesin is an active constituent of the herb aloe vera and plays a crucial role in anti-inflammatory activity, ultraviolet protection, and antibacterium. We investigated the role and possible mechanisms of aloesin in the cell growth and metastasis of ovarian cancer. It was found that aloesin inhibited cell viability and cell clonality in a dose-dependent manner. It arrests the cell cycle at the S-phase and induced apoptosis in SKOV3 cells. In an in vivo experiment, it was observed that aloesin inhibited tumor growth. Moreover, it inhibited migration and invasion of cancer in SKOV3 cells. Interestingly, members from the mitogen-activated protein kinase (MAPK) signaling family became less phosphorylated as the aloesin dose increased. This suggests that aloesin exerts its anticancer effect through the MAPK signaling pathway. Our data also highlights the possibility of using aloesin as a novel therapeutic drug for ovarian cancer treatment.

scholarly journals TRB3 mediates vascular remodeling by activating the MAPK signaling pathway in hypoxic pulmonary hypertension

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xiaopei Cao ◽  
Xiaoyu Fang ◽  
Mingzhou Guo ◽  
Xiaochen Li ◽  
Yuanzhou He ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Protein Expression ◽  
Signaling Pathway ◽  
P38 Mapk ◽  
Vascular Remodeling ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Clinical Samples ◽  
Hypoxic Pulmonary Hypertension

Abstract Background Hypoxic pulmonary hypertension (PH) is a refractory pulmonary vascular remodeling disease, and the efficiency of current PH treatment strategies is unsatisfactory. Tribbles homolog 3 (TRB3), a member of the pseudokinase family, is upregulated in diverse types of cellular stresses and functions as either a pro-proliferative or pro-apoptotic factor depending on the specific microenvironment. The regulatory mechanisms of TRB3 in hypoxic PH are poorly understood. Methods We performed studies using TRB3-specific silencing and overexpressing lentiviral vectors to investigate the potential roles of TRB3 on hypoxic pulmonary artery smooth muscle cells (PASMCs). Adeno-associated virus type 1(AVV1) vectors encoding short-hairpin RNAs against rat TRB3 were used to assess the role of TRB3 on hypoxic PH. TRB3 protein expression in PH patients was explored in clinical samples by western blot analysis. Results The results of whole-rat genome oligo microarrays showed that the expression of TRB3 and endoplasmic reticulum stress (ERS)-related genes was upregulated in hypoxic PASMCs. TRB3 protein expression was significantly upregulated by hypoxia and thapsigargin. In addition, 4-PBA and 4μ8C, both inhibitors of ERS, decreased the expression of TRB3. TRB3 knockdown promoted apoptosis and damaged the proliferative and migratory abilities of hypoxic PASMCs as well as inhibited activation of the MAPK signaling pathway. TRB3 overexpression stimulated the proliferation and migration of PASMCs but decreased the apoptosis of PASMCs, which was partly reversed by specific inhibitors of ERK, JNK and p38 MAPK. The Co-IP results revealed that TRB3 directly interacts with ERK, JNK, and p38 MAPK. Knockdown of TRB3 in rat lung tissue reduced the right ventricular systolic pressure and decreased pulmonary medial wall thickness in hypoxic PH model rats. Further, the expression of TRB3 in lung tissues was higher in patients with PH compared with those who have normal pulmonary artery pressure. Conclusions TRB3 was upregulated in hypoxic PASMCs and was affected by ERS. TRB3 plays a key role in the pathogenesis of hypoxia-induced PH by binding and activating the ERK, JNK, and p38 MAPK pathways. Thus, TRB3 might be a promising target for the treatment of hypoxic PH.

scholarly journals Effect of Total Flavones from Cuscuta Chinensis on Anti-Abortion via the MAPK Signaling Pathway

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hai-wang Wu ◽  
Yi-hui Feng ◽  
Dong-ying Wang ◽  
Wei-yu Qiu ◽  
Qing-ying Yu ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Prolactin Receptor ◽  
Chinese Herb ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Dependent Manner ◽  
Active Components ◽  
Cuscuta Chinensis

For centuries, the Chinese herb Cuscuta chinensis has been applied clinically for abortion prevention in traditional Chinese medicine (TCM). Total flavones extracted from Cuscuta chinensis (TFCC) are one of the active components in the herb and also display anti-abortion effect similar to the unprocessed material. However, how TFCC exerts the anti-abortion effect remains largely unknown. In this study, we aim at characterizing the anti-abortion effects of TFCC and its underlying molecular mechanism in vitro and in vivo using human primary decidua cells and a mifepristone-induced abortion model in rat, respectively. The damage to the decidua caused by mifepristone in vivo was reversed by TFCC treatment in a dosage-dependent manner. High dosage of TFCC significantly upregulated the expression of estrogen receptor (ER), progesterone receptor (PR), and prolactin receptor (PRLR) in decidua tissue but downregulated the expression of p-ERK. Furthermore, we detected higher level of p-ERK and p-p38 in primary decidua cells from spontaneous abortion while treatment by TFCC downregulated their expression. Our results suggest TFCC mediates its anti-abortion effect by interfering with MAPK signaling pathway.

Peroxynitrite reversibly inhibits Ca2+-activated K+ channels in rat cerebral artery smooth muscle cells

2000 ◽  
Vol 278 (6) ◽  
pp. H1883-H1890 ◽  
Author(s):  
Anna K. Brzezinska ◽  
Debebe Gebremedhin ◽  
William M. Chilian ◽  
Balaraman Kalyanaraman ◽  
Stephen J. Elliott
Keyword(s):  
Single Channel ◽  
Cerebral Arteries ◽  
Ionic Current ◽  
Inhibitory Effect ◽  
Bk Channels ◽  
Bk Channel ◽  
Channel Activity ◽  
Open Probability ◽  
Whole Cell ◽  
Cell Current

Peroxynitrite (ONOO−) is a contractile agonist of rat middle cerebral arteries. To determine the mechanism responsible for this component of ONOO−bioactivity, the present study examined the effect of ONOO− on ionic current and channel activity in rat cerebral arteries. Whole cell recordings of voltage-clamped cells were made under conditions designed to optimize K+ current. The effects of iberiotoxin, a selective inhibitor of large-conductance Ca2+-activated K+ (BK) channels, and ONOO− (10–100 μM) were determined. At a pipette potential of +50 mV, ONOO− inhibited 39% of iberiotoxin-sensitive current. ONOO− was selective for iberiotoxin-sensitive current, whereas decomposed ONOO− had no effect. In excised, inside-out membrane patches, channel activity was recorded using symmetrical K+solutions. Unitary currents were sensitive to increases in internal Ca2+ concentration, consistent with activity due to BK channels. Internal ONOO− dose dependently inhibited channel activity by decreasing open probability and mean open times. The inhibitory effect of ONOO− could be overcome by reduced glutathione. Glutathione, added after ONOO−, restored whole cell current amplitude to control levels and reverted single-channel gating to control behavior. The inhibitory effect of ONOO− on membrane K+ current is consistent with its contractile effects in isolated cerebral arteries and single myocytes. Taken together, our data suggest that ONOO− has the potential to alter cerebral vascular tone by inhibiting BK channel activity.

Linkage of G Protein-Coupled Receptors to the MAPK Signaling Pathway Through PI 3-Kinase  

Science ◽  
1997 ◽  
Vol 275 (5298) ◽  
pp. 394-397 ◽  
Author(s):  
M. Lopez-Ilasaca ◽  
P. Crespo ◽  
P. G. Pellici ◽  
J. S. Gutkind ◽  
R. Wetzker
Keyword(s):  
Signaling Pathway ◽  
G Protein ◽  
Mapk Signaling ◽  
G Protein Coupled Receptors ◽  
Mapk Signaling Pathway ◽  
G Protein Coupled

scholarly journals Combined Effect of Deoxynivalenol (DON) and Porcine Circovirus Type 2 (Pcv2) on Inflammatory Cytokine mRNA Expression

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 422
Author(s):  
Chao Gu ◽  
Xiuge Gao ◽  
Dawei Guo ◽  
Jiacai Wang ◽  
Qinghua Wu ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Signaling Pathway ◽  
Porcine Circovirus Type ◽  
Mapk Signaling ◽  
Porcine Circovirus Type 2 ◽  
Mapk Signaling Pathway ◽  
Porcine Circovirus ◽  
Signal Pathways ◽  
Dependent Manner

A host’s immune system can be invaded by mycotoxin deoxynivalenol (DON) poisoning and porcine circovirus type 2 (PCV2) infections, which affect the host’s natural immune function. Pro-inflammatory cytokines, IL-1β and IL-6, are important regulators in the process of natural immune response, which participate in inflammatory response and enhance immune-mediated tissue damage. Preliminary studies have shown that DON promotes PCV2 infection by activating the MAPK signaling pathway. Here, we explored whether the mRNA expression of IL-1β and IL-6, induced by the combination of DON and PCV2, would depend on the MAPK signaling pathway. Specific pharmacological antagonists U0126, SP600125 and SB203580, were used to inhibit the activities of ERK, JNK and p38 in the MAPK signaling pathway, respectively. Then, the mRNA expression of IL-1β and IL-6 in PK-15 cells was detected to explore the effect of the MAPK signaling pathway on IL-1β and IL-6 mRNA induced by DON and PCV2. The results showed that PK-15 cells treated with DON or PCV2 induced the mRNA expression of IL-1β and IL-6 in a time- and dose-dependent manner. The combination of DON and PCV2 has an additive effect on inducing the mRNA expression of IL-1β and IL-6. Additionally, both DON and PCV2 could induce the mRNA expression of IL-1β and IL-6 via the ERK and the p38 MAPK signal pathways, while PCV2 could induce it via the JNK signal pathway. Taken together, our results suggest that MAPKs play a contributory role in IL-1β and IL-6 mRNA expression when induced by both DON and PCV2.

scholarly journals Glycinin-induced porcine IPEC-J2 cells damage via the NF-κB/MAPK signaling pathway

2020 ◽  
Author(s):  
Chenglu Peng ◽  
Zhifeng Sun ◽  
Lei Wang ◽  
Yingshuang Shu ◽  
Mengchu He ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Intestinal Barrier ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Control Group ◽  
Epithelial Cell Line ◽  
Pyrrolidine Dithiocarbamate ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Nitric Oxide Synthase Inhibitor

Abstract Background: Glycinin, a protein found in soybean, is a human and animal allergen that causes damage to the intestinal barrier. However, its mechanisms of action remain unclear. Therefore, in this study, the intestinal porcine epithelial cell line IPEC-J2 was used to evaluate the effect of glycinin concentration on the intestinal epithelium and identify the related signaling pathways. Results: IPEC-J2 cells were divided into seven treatment groups and a control group; the cells were treated for 24 h with 1, 5, or 10 mg/mL glycinin or with 5 mg/mL glycinin after 30 min of pre-treatment with 1 μmol/L nuclear factor-kappa B (NF-κB) inhibitor (pyrrolidine dithiocarbamate), inducible nitric oxide synthase inhibitor ( N -ω-nitro-l-arginine methyl ester), Jun N-terminal kinase (JNK) inhibitor (SP600125), or p38 inhibitor (SB202190). A series of molecular and biochemical experiments revealed that the levels of NF-κB, p38, and JNK, as well as their downstream proteins, were increased after treatment compared to those in the control group. Conclusion: Glycinin damaged IPEC-J2 cells in a concentration-dependent manner via the NF-κB/MAPK signaling pathway.

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