scholarly journals Stomach gastrin is regulated by sodium via PPAR-α and dopamine D1 receptor

2020 ◽  
Vol 64 (2) ◽  
pp. 53-65
Author(s):  
Peng Xu ◽  
John J Gildea ◽  
Chi Zhang ◽  
Prasad Konkalmatt ◽  
Santiago Cuevas ◽  
...  
Keyword(s):  
Protein Expression ◽  
Critical Role ◽  
D1 Receptor ◽  
Dietary Sodium ◽  
Peroxisome Proliferator ◽  
Ovarian Adenocarcinoma ◽  
G Cells ◽  
Gastrin Secretion ◽  
Adenocarcinoma Cells ◽  
Human Gastrin

Gastrin, secreted by stomach G cells in response to ingested sodium, stimulates the renal cholecystokinin B receptor (CCKBR) to increase renal sodium excretion. It is not known how dietary sodium, independent of food, can increase gastrin secretion in human G cells. However, fenofibrate (FFB), a peroxisome proliferator-activated receptor-α (PPAR-α) agonist, increases gastrin secretion in rodents and several human gastrin-secreting cells, via a gastrin transcriptional promoter. We tested the following hypotheses: (1.) the sodium sensor in G cells plays a critical role in the sodium-mediated increase in gastrin expression/secretion, and (2.) dopamine, via the D1R and PPAR-α, is involved. Intact human stomach antrum and G cells were compared with human gastrin-secreting gastric and ovarian adenocarcinoma cells. When extra- or intracellular sodium was increased in human antrum, human G cells, and adenocarcinoma cells, gastrin mRNA and protein expression/secretion were increased. In human G cells, the PPAR-α agonist FFB increased gastrin protein expression that was blocked by GW6471, a PPAR-α antagonist, and LE300, a D1-like receptor antagonist. LE300 prevented the ability of FFB to increase gastrin protein expression in human G cells via the D1R, because the D5R, the other D1-like receptor, is not expressed in human G cells. Human G cells also express tyrosine hydroxylase and DOPA decarboxylase, enzymes needed to synthesize dopamine. G cells in the stomach may be the sodium sensor that stimulates gastrin secretion, which enables the kidney to eliminate acutely an oral sodium load. Dopamine, via the D1R, by interacting with PPAR-α, is involved in this process.

KIF3B gene silent variant leading to sperm morphology and motility defects and male infertility

2021 ◽  
Author(s):  
Raheleh Heydari ◽  
Mehrshad Seresht-Ahmadi ◽  
Shahab Mirshahvaladi ◽  
Marjan Sabbaghian ◽  
Anahita Mohseni-Meybodi
Keyword(s):  
Male Infertility ◽  
Protein Expression ◽  
Binding Site ◽  
Sperm Count ◽  
Critical Role ◽  
Coiled Coil ◽  
Control Group ◽  
Coding Region ◽  
Exon 2 ◽  
Coiled Coil Domain

Abstract Sperm structural and functional defects are leading causes of male infertility. Patients with immotile sperm disorders suffer from axoneme failure and show a significant reduction in sperm count. The kinesin family member 3B (KIF3B) is one of the genes involved in the proper formation of sperm with a critical role in intraflagellar and intramanchette transport. A part of exon 2 and exons 3–5 of the KIF3B encodes a protein coiled-coil domain that interacts with IFT20 from the IFT protein complex. In the present study, the coding region of KIF3B coiled-coil domain was assessed in 88 oligoasthenoteratozoospermic patients, and the protein expression was evaluated in the mature spermatozoa of the case and control groups using immunocytochemistry and western blotting. According to the results, there was no genetic variation in the exons 3–5 of the KIF3B, but a new A > T variant was identified within the exon 2 in 30 patients, where nothing was detected in the control group. In contrast to healthy individuals, significantly reduced protein expression was observable in oligoasthenoteratozoospermic (OAT) patients carrying variation where protein organization was disarranged, especially in the principal piece and midpiece of the sperm tail. Besides, the protein expression level was lower in the patients’ samples compared to that of the control group. According to the results of the present study the NM_004798.3:c.1032A > T, p.Pro344 = variant; which has been recently submitted to the Clinvar database; although synonymous, causes alterations in the transcription factor binding site, exon skipping, and also exonic splicing enhancer-binding site. Therefore, KIF3B can play an important role in spermatogenesis and the related protein reduction can cause male infertility.

scholarly journals The Hinge-Helix 1 Region of Peroxisome Proliferator-Activated Receptor γ1 (PPARγ1) Mediates Interaction with Extracellular Signal-Regulated Kinase 5 and PPARγ1 Transcriptional Activation: Involvement in Flow-Induced PPARγ Activation in Endothelial Cells

2004 ◽  
Vol 24 (19) ◽  
pp. 8691-8704 ◽  
Author(s):  
Masashi Akaike ◽  
Wenyi Che ◽  
Nicole-Lerner Marmarosh ◽  
Shinsuke Ohta ◽  
Masaki Osawa ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Adhesion Molecule ◽  
Critical Role ◽  
Physiological Role ◽  
Cellular Adhesion ◽  
Dominant Negative ◽  
Peroxisome Proliferator ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Cellular Adhesion Molecule

ABSTRACT Peroxisome proliferator-activated receptors (PPAR) are ligand-activated transcription factors that form a subfamily of the nuclear receptor gene family. Since both flow and PPARγ have atheroprotective effects and extracellular signal-regulated kinase 5 (ERK5) kinase activity is significantly increased by flow, we investigated whether ERK5 kinase regulates PPARγ activity. We found that activation of ERK5 induced PPARγ1 activation in endothelial cells (ECs). However, we could not detect PPARγ phosphorylation by incubation with activated ERK5 in vitro, in contrast to ERK1/2 and JNK, suggesting a role for ERK5 as a scaffold. Endogenous PPARγ1 was coimmunoprecipitated with endogenous ERK5 in ECs. By mammalian two-hybrid analysis, we found that PPARγ1 associated with ERK5a at the hinge-helix 1 region of PPARγ1. Expressing a hinge-helix 1 region PPARγ1 fragment disrupted the ERK5a-PPARγ1 interaction, suggesting a critical role for hinge-helix 1 region of PPARγ in the ERK5-PPARγ interaction. Flow increased ERK5 and PPARγ1 activation, and the hinge-helix 1 region of the PPARγ1 fragment and dominant negative MEK5β significantly reduced flow-induced PPARγ activation. The dominant negative MEK5β also prevented flow-mediated inhibition of tumor necrosis factor alpha-mediated NF-κB activation and adhesion molecule expression, including vascular cellular adhesion molecule 1 and E-selectin, indicating a physiological role for ERK5 and PPARγ activation in flow-mediated antiinflammatory effects. We also found that ERK5 kinase activation was required, likely by inducing a conformational change in the NH2-terminal region of ERK5 that prevented association of ERK5 and PPARγ1. Furthermore, association of ERK5a and PPARγ1 disrupted the interaction of SMRT and PPARγ1, thereby inducing PPARγ activation. These data suggest that ERK5 mediates flow- and ligand-induced PPARγ activation via the interaction of ERK5 with the hinge-helix 1 region of PPARγ.

scholarly journals Enhanced expression of the complement regulatory protein, membrane inhibitor of reactive lysis (CD59), is regulated at the level of transcription

Blood ◽  
1993 ◽  
Vol 82 (3) ◽  
pp. 968-977
Author(s):  
MH Holguin ◽  
CB Martin ◽  
JH Weis ◽  
CJ Parker
Keyword(s):  
Protein Expression ◽  
Blot Analysis ◽  
Interleukin 1 ◽  
Critical Role ◽  
Regulatory Protein ◽  
Calcium Ionophore ◽  
Cytolytic Activity ◽  
Host Cells ◽  
Rna Expression ◽  
Enhanced Expression

The membrane inhibitor of reactive lysis (MIRL) is an 18-Kd glycosyl phosphatidylinositol anchored membrane glycoprotein that inhibits the cytolytic activity of complement. MIRL is expressed by all hematopoietic elements and by a wide variety of nonhematopoietic tissues. A deficiency of MIRL is primarily responsible for the greater sensitivity of the erythrocytes of paroxysmal nocturnal hemoglobinuria to complement mediated lysis. Because of its critical role in protecting host cells from injury by complement, we hypothesized that mechanisms exist that allow MIRL expression to be regulated. To investigate this hypothesis, both MIRL RNA and MIRL protein expression were analyzed following exposure of K562 erythroleukemia cells to a variety of potential stimulants. Incubation with dexamethasone, calcium ionophore, lipopolysaccharide, interleukin 1, tumor necrosis factor, hemin, and cyclic AMP had no effect on MIRL expression. However, incubation with phorbol 12-myristate 13 acetate (PMA), induced a marked increase in MIRL RNA as determined by Northern blot analysis. This enhanced expression of MIRL RNA was associated with an increase in MIRL protein expression as determined by immunoprecipitation of metabolically labeled proteins, Western blot analysis, and immunobinding assay. Enhanced MIRL RNA expression was first detected after 8 hours and increased through 24 hours of observation. Inhibitors of either protein synthesis or transcription abrogated the PMA-induced enhancement of MIRL RNA expression. Together, these results are consistent with a model in which PMA induces synthesis of a trans acting protein that enhances transcription of the MIRL gene.

scholarly journals CD437 induces apoptosis in ovarian adenocarcinoma cells via ER stress signaling

2008 ◽  
Vol 366 (3) ◽  
pp. 840-847 ◽  
Author(s):  
Yumi Watanabe ◽  
Hiroyuki Tsuchiya ◽  
Tomohiko Sakabe ◽  
Saori Matsuoka ◽  
Yuji Akechi ◽  
...  
Keyword(s):  
Er Stress ◽  
Stress Signaling ◽  
Ovarian Adenocarcinoma ◽  
Adenocarcinoma Cells

Abstract 15931: Glycogen Synthase Kinase-3α Plays a Critical Role in the Development of Cardiac Dysfunction During Obesity and Insulin Resistance Through Phosphorylation of Peroxisome Proliferator-Activated Receptor α

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Michinari Nakamura ◽  
Peiyong Zhai ◽  
Junichi Sadoshima
Keyword(s):  
Insulin Resistance ◽  
Cardiac Hypertrophy ◽  
Diastolic Dysfunction ◽  
Cardiac Dysfunction ◽  
Lipid Accumulation ◽  
Glycogen Synthase ◽  
Critical Role ◽  
Cardiac Metabolism ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Obesity and insulin resistance (IR) lead to impaired cardiac metabolism, resulting in cardiac dysfunction. However, the underlying mechanisms responsible for the development of cardiac dysfunction remain poorly understood. PPARα serves as a key regulator of fatty acid (FA) metabolism in the heart. GSK-3α, a serine/threonine kinase, was dephosphorylated at S21 and activated (2.0 fold, p<0.05) in the hearts of obese mice fed a high-fat diet (HFD) and ob/ob mice. To evaluate the functional significance of GSK-3α upregulation, wild-type (WT) and cardiac specific GSK-3α heterozygous knockout (cGSK-3α HKO) mice were fed a HFD for up to 14 weeks. There was no difference in the food intake or body weight change between WT and cGSK-3α HKO mice. However, cardiac hypertrophy and diastolic dysfunction observed in WT mice were significantly ameliorated in cGSK-3α HKO mice after HFD feeding (8.1± 0.6 and 6.5±0.5, LVW/TL; 24.8±0.9 and 16.6±0.8, deceleration time (DT), all p<0.05). FA oxidation (FAO) (0.81 fold) and ectopic lipid accumulation (Oil Red O staining) were significantly decreased in cGSK-3α HKO mice than in WT mice after HFD feeding. GSK-3α, but not GSK-3β, directly interacted with and phosphorylated PPARα at the ligand binding domain in cardiomyocytes (CMs) and in the heart. PPARα phosphorylation in the heart was significantly increased (2.1 fold, p<0.05) in response to HFD, but it was attenuated in cGSK-3α HKO mice (0.74 fold, p<0.05). Fenofibrate, a PPARα ligand, inhibited GSK-3α-induced PPARα phosphorylation (0.81 fold, p<0.05), reduced ectopic lipid accumulation, FAO (0.84 fold, p<0.05), and attenuated diastolic dysfunction (25.5±3.1 and 18.6±2.5, DT; 0.16±0.04 and 0.08±0.02, EDPVR, all p<0.05) in the heart of HFD fed mice. Collectively, these results suggest that GSK-3α increases PPARα activity through phosphorylation of PPARα, which is inhibited by Fenofibrate. Activation of GSK-3α and consequent phosphorylation of PPARα during obesity and IR could play an important role in the development of cardiac hypertrophy and diastolic dysfunction. Synthetic PPARα ligands inhibit GSK-3α-mediated phosphorylation of PPARα, thereby paradoxically attenuating excessive FA metabolism in cardiomyocytes.

Abstract 310: Deoxycorticosterone Acetate (doca)-salt Exacerbates Hypertension and Vascular Dysfunction in Mice Expressing Dominant Negative Peroxisome Proliferator-activated Receptor-gamma (pparg) in Smooth Muscle

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Pimonrat Ketsawatsomkron ◽  
Deborah R Davis ◽  
Aline M Hilzendeger ◽  
Justin L Grobe ◽  
Curt D Sigmund
Keyword(s):  
Blood Pressure ◽  
Smooth Muscle ◽  
Transgenic Mice ◽  
Vascular Function ◽  
Vascular Dysfunction ◽  
Critical Role ◽  
Surrogate Marker ◽  
Dominant Negative ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

PPARG, a ligand-activated transcription factor plays a critical role in the regulation of blood pressure and vascular function. We hypothesized that smooth muscle cell (SMC) PPARG protects against hypertension (HT) and resistance vessel dysfunction. Transgenic mice expressing dominant negative PPARG (S-P467L) in SMC or non-transgenic controls (NT) were implanted with DOCA pellet and allowed ad libitum access to 0.15 M NaCl for 21 days in addition to regular chow and water. Blood pressure was monitored by telemetry and mesenteric arterial (MA) function was assessed by pressurized myograph. At baseline, 24-hour mean arterial pressure (MAP) was similar between NT and S-P467L mice, while the transgenic mice were tachycardic. DOCA-salt increased MAP to a much greater degree in S-P467L mice (Δ MAP; S-P467L: +34.2±6.0, NT: +13.3±5.7, p<0.05 vs NT). Heart rate was similarly decreased in both groups after DOCA-salt. Vasoconstriction to KCl, phenylephrine and endothelin-1 did not differ in MA from DOCA-salt treated NT and S-P467L, while the response to vasopressin was significantly reduced in S-P467L after DOCA-salt (% constriction at 10-8 M, S-P467L: 31.6±5.6, NT: 46.7±3.8, p<0.05 vs NT). Urinary copeptin, a surrogate marker for arginine vasopressin was similar in both groups regardless of treatment. Vasorelaxation to acetylcholine was slightly impaired in S-P467L MA compared to NT at baseline whereas this effect was further exaggerated after DOCA-salt (% relaxation at 10-5 M, S-P467L: 56.1±8.3, NT: 79.4±5.6, p<0.05 vs NT). Vascular morphology at luminal pressure of 75 mmHg showed a significant increase in wall thickness (S-P467L: 18.7±0.8, NT: 16.0±0.4, p<0.05 vs NT) and % media/lumen (S-P467L: 8.4±0.3, NT: 7.1±0.2, p<0.05 vs NT) in S-P467L MA after DOCA-salt. Expression of tissue inhibitor of metalloproteinases (TIMP)-4 and regulator of G-protein signaling (RGS)-5 transcript were 2- and 3.5-fold increased, respectively, in MA of NT with DOCA-salt compared to NT baseline. However, this induction was markedly blunted in S-P467L MA. We conclude that interference with PPARG function in SMC leads to altered gene expression crucial for normal vascular homeostasis, thereby sensitizing the mice to the effects of DOCA-salt induced HT and vascular dysfunction.

scholarly journals SUN-559 Involvement of Sarco/Endoplasmic Reticulum Ca- ATPase (SERCA) in Membrane Progesterone Receptor Alpha (PAQR7)-Mediated Progesterone Induction of Vascular Smooth Muscle Relaxation

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Yefei Pang ◽  
Peter Thomas
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Muscle ◽  
Progesterone Receptor ◽  
Protein Expression ◽  
Signaling Pathways ◽  
Muscle Relaxation ◽  
Critical Role ◽  
Akt Signaling ◽  
Membrane Progesterone Receptor ◽  
Membrane Progesterone Receptor Alpha

Abstract Progesterone (P4) exerts multiple beneficial effects on the human cardiovascular system through its actions on vascular endothelial cells and also by acting directly on vascular smooth muscle cells (VSMCs). Membrane progesterone receptor alpha (mPRα) has been shown to mediate the rapid P4-induction of human VSMC relaxation through activation of MAPK, Akt/Pi3k and RhoA/ROCK signaling pathways and the resulting reduction of calcium influx through calcium channels. In this study, we demonstrate that treatment of cultured human VSMCs with P4 for 1-2 hours increases both the mRNA and protein expression of sarco/endoplasmic reticulum Ca- ATPase (SERCA), the major transporter of calcium from the cytosol into the sarcoplasmic reticulum (SR) during muscle relaxation. Knockdown of mPRα with siRNA completely blocked this stimulatory effect of P4 as well as that of OD 02-0, a mPR selective agonist, on SERCA protein expression. In contrast, expression levels of phospholamban (PLB), a SR protein that reversibly inhibits SERCA were downregulated by this P4 treatment, and mRNA expression of a channel that releases calcium from the SR, inositol trisphosphate receptor (IP3R), was unaltered after treatment with P4. Moreover, treatments with P4 and OD 02-0, but not with R5020, a nuclear PR agonist, increased PLB phosphorylation, which would result in disinhibition of SERCA function. P4 and OD 02-0 significantly increased calcium levels in the SR detected with Fluo-5N, a specific SR calcium indicator, and caused VSMC relaxation. These effects were blocked by cyclopiazonic acid (CPA, a SERCA inhibitor), suggesting that SERCA plays a critical role in P4 induction of VSMC relaxation. Similarly, the effects of P4 and OD 02-0 on relaxation of umbilical artery rings measured with a myograph were significantly attenuated by CPA, which confirms the critical role of SERCA in the rapid action of P4 and 02-0 on vascular muscle relaxation. P4 has previously been shown to activate MAPK and Akt signaling pathways to induce VSMC relaxation. The P4- and OD 02-0-induced increases in calcium in the SR were blocked by MAPK and Akt/Pi3k signaling inhibitors, AZD6244 and wortmannin. Taken together, these results suggest that the direct, rapid effects of P4 on relaxation of VSMCs through mPRα involves regulation of the expression and function of the SR proteins SERCA and PLB through MAPK and Akt signaling pathways.

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