Deficiency of MicroRNA-181a Results in Transcriptome-Wide Cell-Specific Changes in the Kidney and Increases Blood Pressure

Hypertension ◽  
2021 ◽  
Vol 78 (5) ◽  
pp. 1322-1334
Author(s):  
Madeleine R. Paterson ◽  
Kristy L. Jackson ◽  
Malathi S.I. Dona ◽  
Gabriella E. Farrugia ◽  
Bruna Visniauskas ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Molecular Mechanisms ◽  
Salt Sensitivity ◽  
Juxtaglomerular Cells ◽  
Renal Cells ◽  
Cell Level ◽  
Knockout Mouse Model ◽  
Nerve Development

MicroRNA miR-181a is downregulated in the kidneys of hypertensive patients and hypertensive mice. In vitro, miR-181a is a posttranslational inhibitor of renin expression, but pleiotropic mechanisms by which miR-181a may influence blood pressure (BP) are unknown. Here, we determined whether deletion of miR-181a/b-1 in vivo changes BP and the molecular mechanisms involved at the single-cell level. We developed a KO (knockout) mouse model lacking miR-181a/b-1 genes using CRISPR/Cas9 technology. Radiotelemetry probes were implanted in 12-week-old C57BL/6J WT (wild type) and miR-181a/b-1 KO mice. Systolic and diastolic BP were 4- to 5-mm Hg higher in KO compared with WT mice over 24 hours ( P <0.01). Compared with WT mice, renal renin was higher in the juxtaglomerular cells of KO mice. BP was similar in WT mice on a high- (3.1%) versus low- (0.3%) sodium diet (+0.4±0.8 mm Hg), but KO mice showed salt sensitivity (+3.3±0.8 mm Hg; P <0.001). Since microRNAs can target several mRNAs simultaneously, we performed single-nuclei RNA sequencing in 6699 renal cells. We identified 12 distinct types of renal cells, all of which had genes that were dysregulated. This included genes involved in renal fibrosis and inflammation such as Stat4 , Col4a1 , Cd81 , Flt3l , Cxcl16 , and Smad4 . We observed upregulation of pathways related to the immune system, inflammatory response, reactive oxygen species, and nerve development, consistent with higher tyrosine hydroxylase in the kidney. In conclusion, downregulation of the miR-181a gene led to increased BP and salt sensitivity in mice. This is likely due to an increase in renin expression in juxtaglomerular cells, as well as microRNA-driven pleiotropic effects impacting renal pathways associated with hypertension.

scholarly journals Deficiency of MicroRNA-181a Results in Transcriptome-Wide Cell Specific Changes in the Kidney that Lead to Elevated Blood Pressure and Salt Sensitivity

2021 ◽  
Author(s):  
Madeleine R. Paterson ◽  
Kristy L. Jackson ◽  
Malathi I. Dona ◽  
Gabriella E. Farrugia ◽  
Bruna Visniauskas ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Knockout Mice ◽  
Molecular Mechanisms ◽  
Salt Sensitivity ◽  
Juxtaglomerular Cells ◽  
Renal Cells ◽  
Wild Type ◽  
Knockout Mouse Model

AbstractMicroRNA miR-181a is down-regulated in the kidneys of hypertensive patients and hypertensive mice. In vitro, miR-181a is a posttranslational inhibitor of renin expression, but pleiotropic mechanisms by which miR-181a may influence blood pressure (BP) are unknown. Here we determined whether deletion of miR-181a/b-1 in vivo changes BP and the molecular mechanisms involved at the single-cell level. We developed a knockout mouse model lacking miR-181a/b-1 genes using CRISPR/Cas9 technology. Radio-telemetry probes were implanted in twelve-week-old C57BL/6J wild-type and miR-181a/b-1 knockout mice. Systolic and diastolic BP were 4-5mmHg higher in knockout compared with wild-type mice over 24-hours (P<0.01). Compared with wild-type mice, renal renin was higher in the juxtaglomerular cells of knockout mice. BP was similar in wild-type mice on a high (3.1%) versus low (0.3%) sodium diet (+0.4±0.8mmHg) but knockout mice showed salt sensitivity (+3.3±0.8mmHg, P<0.001). Since microRNAs can target several mRNAs simultaneously, we performed single-nuclei RNA-sequencing in 6,699 renal cells. We identified 12 distinct types of renal cells, all of which had genes that were dysregulated. This included genes involved in renal fibrosis and inflammation such as Stat4, Col4a1, Cd81, Flt3l, Cxcl16, Smad4. We observed up-regulation of pathways related to the immune system, inflammatory response, reactive oxygen species and nerve development, consistent with higher tyrosine hydroxylase. In conclusion, downregulation of the miR-181a gene led to increased BP and salt sensitivity in mice. This is likely due to an increase in renin expression in juxtaglomerular cells, as well as microRNA-driven pleiotropic effects impacting renal pathways associated with hypertension.

Abstract 066: The Undescribed Protein Caskin2 Is a Novel Regulator of eNOS Phosphorylation and Systemic Blood Pressure

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Sarah B Mueller ◽  
Susan B Gurley ◽  
Christopher D Kontos
Keyword(s):  
Blood Pressure ◽  
Molecular Mechanisms ◽  
Systemic Blood Pressure ◽  
Regulatory Subunit ◽  
Systemic Blood ◽  
Homologous Expression ◽  
Ongoing Work ◽  
Inducing Factors

Disruptions in the function of the quiescent endothelial cells (ECs) that line mature vessels can both result in and contribute to the progression of numerous cardiovascular diseases including hypertension, atherosclerosis, and disorders of vascular permeability. Despite recent attention, the signaling pathways that are active in quiescent ECs remain poorly characterized relative to those that regulate EC activation. In an effort to provide mechanistic insight into these pathways, we have characterized the previously undescribed protein Caskin2, which we hypothesize is a novel regulator of EC quiescence. Caskin2 is expressed in ECs throughout the vasculature, including the aorta, coronary arteries, and renal glomeruli. In vitro, Caskin2 promotes a quiescent EC phenotype characterized by decreased proliferation and increased resistance to apoptosis-inducing factors. Caskin2 knockout mice are viable and fertile. However, preliminary radiotelemetry measurements indicate that Caskin2 knockout (KO) mice have mildly elevated systemic blood pressure (BP). Compared to wild type (WT) littermates (n=8), Caskin2 KO mice (n=7) had increased mean arterial pressure (119+/-1 vs. 113+/-1, p=0.012), systolic BP (138+/-2 vs. 132+/-2, p=0.023), and diastolic BP (99+/-1 vs. 93+/-1, p=0.014) at baseline. To explore the molecular mechanisms of Caskin2’s effects, we used mass spectrometry to identify interacting proteins. Among the 67 proteins identified were the Ser/Thr phosphatase protein phosphatase 1 (PP1) and eNOS. Using standard in vitro biochemical techniques, we demonstrated that Caskin2 acts as a PP1 regulatory subunit. Interestingly, homologous expression of Caskin2 in vitro resulted in a marked increase in phosphorylation of eNOS on S1177, which is known to promote eNOS activity, and a decrease in phosphorylation on T495, which is associated with eNOS inhibition. Finally, PP1 has been shown to dephosphorylate eNOS T495 in vitro, suggesting a molecular mechanism for our in vivo findings. Ongoing work aims to determine if the interaction of Caskin2 and PP1 is required for the Caskin2-induced increase in activating phosphorylation of eNOS and to characterize the physiological mechanisms responsible for Caskin2’s effects on BP in more detail.

scholarly journals Endothelial Sphingolipid De Novo Synthesis Controls Blood Pressure by Regulating Signal Transduction and NO via Ceramide

Hypertension ◽  
2020 ◽  
Vol 75 (5) ◽  
pp. 1279-1288 ◽  
Author(s):  
Anna Cantalupo ◽  
Linda Sasset ◽  
Antonella Gargiulo ◽  
Luisa Rubinelli ◽  
Ilaria Del Gaudio ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Signal Transduction ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Control Flow ◽  
Serine Palmitoyltransferase ◽  
Blood Pressure Homeostasis

Ceramides are sphingolipids that modulate a variety of cellular processes via 2 major mechanisms: functioning as second messengers and regulating membrane biophysical properties, particularly lipid rafts, important signaling platforms. Altered sphingolipid levels have been implicated in many cardiovascular diseases, including hypertension, atherosclerosis, and diabetes mellitus–related conditions; however, molecular mechanisms by which ceramides impact endothelial functions remain poorly understood. In this regard, we generated mice defective of endothelial sphingolipid de novo biosynthesis by deleting the Sptlc2 (long chain subunit 2 of serine palmitoyltransferase)—the first enzyme of the pathway. Our study demonstrated that endothelial sphingolipid de novo production is necessary to regulate (1) signal transduction in response to NO agonists and, mainly via ceramides, (2) resting eNOS (endothelial NO synthase) phosphorylation, and (3) blood pressure homeostasis. Specifically, our findings suggest a prevailing role of C16:0-Cer in preserving vasodilation induced by tyrosine kinase and GPCRs (G-protein coupled receptors), except for Gq-coupled receptors, while C24:0- and C24:1-Cer control flow-induced vasodilation. Replenishing C16:0-Cer in vitro and in vivo reinstates endothelial cell signaling and vascular tone regulation. This study reveals an important role of locally produced ceramides, particularly C16:0-, C24:0-, and C24:1-Cer in vascular and blood pressure homeostasis, and establishes the endothelium as a key source of plasma ceramides. Clinically, specific plasma ceramides ratios are independent predictors of major cardiovascular events. Our data also suggest that plasma ceramides might be indicative of the diseased state of the endothelium.

scholarly journals Upregulation of Na+ and Ca2+ transporters in arterial smooth muscle from ouabain-induced hypertensive rats

2010 ◽  
Vol 298 (1) ◽  
pp. H263-H274 ◽  
Author(s):  
Maria V. Pulina ◽  
Alessandra Zulian ◽  
Roberto Berra-Romani ◽  
Olga Beskina ◽  
Amparo Mazzocco-Spezzia ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Smooth Muscle ◽  
Molecular Mechanisms ◽  
Transient Receptor Potential ◽  
Protein A ◽  
Receptor Potential ◽  
Atpase Inhibitor ◽  
Rna Knockdown

Prolonged ouabain administration (25 μg·kg−1·day−1 for 5 wk) induces “ouabain hypertension” (OH) in rats, but the molecular mechanisms by which ouabain elevates blood pressure are unknown. Here, we compared Ca2+ signaling in mesenteric artery smooth muscle cells (ASMCs) from normotensive (NT) and OH rats. Resting cytosolic free Ca2+ concentration ([Ca2+]cyt; measured with fura-2) and phenylephrine-induced Ca2+ transients were augmented in freshly dissociated OH ASMCs. Immunoblots revealed that the expression of the ouabain-sensitive α2-subunit of Na+ pumps, but not the predominant, ouabain-resistant α1-subunit, was increased (2.5-fold vs. NT ASMCs) as was Na+/Ca2+ exchanger-1 (NCX1; 6-fold vs. NT) in OH arteries. Ca2+ entry, activated by sarcoplasmic reticulum (SR) Ca2+ store depletion with cyclopiazonic acid (SR Ca2+-ATPase inhibitor) or caffeine, was augmented in OH ASMCs. This reflected an augmented expression of 2.5-fold in OH ASMCs of C-type transient receptor potential TRPC1, an essential component of store-operated channels (SOCs); two other components of some SOCs were not expressed (TRPC4) or were not upregulated (TRPC5). Ba2+ entry activated by the diacylglycerol analog 1-oleoyl-2-acetyl- sn-glycerol [a measure of receptor-operated channel (ROC) activity] was much greater in OH than NT ASMCs. This correlated with a sixfold upregulation of TRPC6 protein, a ROC family member. Importantly, in primary cultured mesenteric ASMCs from normal rats, 72-h treatment with 100 nM ouabain significantly augmented NCX1 and TRPC6 protein expression and increased resting [Ca2+]cyt and ROC activity. SOC activity was also increased. Silencer RNA knockdown of NCX1 markedly downregulated TRPC6 and eliminated the ouabain-induced augmentation; silencer RNA knockdown of TRPC6 did not affect NCX1 expression but greatly attenuated its upregulation by ouabain. Clearly, NCX1 and TRPC6 expression are interrelated. Thus, prolonged ouabain treatment upregulates the Na+ pump α2-subunit-NCX1-TRPC6 (ROC) Ca2+ signaling pathway in arterial myocytes in vitro as well as in vivo. This may explain the augmented myogenic responses and enhanced phenylephrine-induced vasoconstriction in OH arteries ( 83 ) as well as the high blood pressure in OH rats.

scholarly journals NLK is required for Ras/ERK/SRF/ELK signaling to tune skeletal muscle development by phosphorylating SRF and antagonizing the SRF/MKL pathway

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Shang-Ze Li ◽  
Ze-Yan Zhang ◽  
Jie Chen ◽  
Ming-You Dong ◽  
Xue-Hua Du ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Molecular Mechanisms ◽  
Muscle Development ◽  
Serum Response Factor ◽  
Conditional Knockout ◽  
Myoblast Differentiation ◽  
Knockout Mouse Model ◽  
Hypertrophic Growth

AbstractSerum response factor (SRF) regulates differentiation and proliferation by binding to RhoA-actin-activated MKL or Ras-MAPK-activated ELK transcriptional coactivators, but the molecular mechanisms responsible for SRF regulation remain unclear. Here, we show that Nemo-like kinase (NLK) is required for the promotion of SRF/ELK signaling in human and mouse cells. NLK was found to interact with and phosphorylate SRF at serine residues 101/103, which in turn enhanced the association between SRF and ELK. The enhanced affinity of SRF/ELK antagonized the SRF/MKL pathway and inhibited mouse myoblast differentiation in vitro. In a skeletal muscle-specific Nlk conditional knockout mouse model, forming muscle myofibers underwent hypertrophic growth, resulting in an increased muscle and body mass phenotype. We propose that both phosphorylation of SRF by NLK and phosphorylation of ELKs by MAPK are required for RAS/ELK signaling, confirming the importance of this ancient pathway and identifying an important role for NLK in modulating muscle development in vivo.

scholarly journals Homeostatic Response of Mouse renin Gene Transcription in a Hypertensive Environment Is Mediated by a Novel 5′ Enhancer

2018 ◽  
Vol 38 (7) ◽  
Author(s):  
Aki Ushiki ◽  
Hitomi Matsuzaki ◽  
Akiyoshi Fukamizu ◽  
Keiji Tanimoto
Keyword(s):  
Blood Pressure ◽  
Gene Transcription ◽  
Molecular Mechanisms ◽  
Renin Angiotensin System ◽  
Feedback Mechanism ◽  
Enhancer Activity ◽  
Basal Expression ◽  
The One

ABSTRACT The renin-angiotensin system plays an essential role in blood pressure homeostasis. Because renin activity is reflected as a blood pressure phenotype, its gene expression in the kidney is tightly regulated by a feedback mechanism; i.e., renin gene transcription is suppressed in a hypertensive state. To address the molecular mechanisms controlling hypertension-responsive mouse renin (m Ren ) gene regulation, we deleted either 5′ (17-kb) or 3′ (78-kb) regions of the endogenous m Ren gene and placed the animals in a hypertensive environment. While the m Ren gene bearing the 3′ deletion was appropriately downregulated, the one bearing the 5′ deletion lost this hypertension responsiveness. Because the 17-kb sequence exhibited enhancer activity in vivo and in vitro , we narrowed down the enhancer to a 2.3-kb core using luciferase assays in As4.1 cells. When this 2.3-kb sequence was removed from the endogenous m Ren gene in the mouse, its basal expression was dramatically reduced, and the hypertension responsiveness was significantly attenuated. Furthermore, we demonstrated that the angiotensin II signal played an important role in m Ren gene suppression. We propose that in a hypertensive environment, the activity of this novel enhancer is attenuated, and, as a consequence, m Ren gene transcription is suppressed to maintain blood pressure.

Flavonoids as P-gp Inhibitors: A Systematic Review of SARs

2019 ◽  
Vol 26 (25) ◽  
pp. 4799-4831 ◽  
Author(s):  
Jiahua Cui ◽  
Xiaoyang Liu ◽  
Larry M.C. Chow
Keyword(s):  
Molecular Mechanisms ◽  
Metastatic Cancer ◽  
Drug Candidates ◽  
Chemical Structures ◽  
Transporter Family ◽  
Promising Area ◽  
New Generation ◽  
Nontoxic Inhibitors

P-glycoprotein, also known as ABCB1 in the ABC transporter family, confers the simultaneous resistance of metastatic cancer cells towards various anticancer drugs with different targets and diverse chemical structures. The exploration of safe and specific inhibitors of this pump has always been the pursuit of scientists for the past four decades. Naturally occurring flavonoids as benzopyrone derivatives were recognized as a class of nontoxic inhibitors of P-gp. The recent advent of synthetic flavonoid dimer FD18, as a potent P-gp modulator in reversing multidrug resistance both in vitro and in vivo, specifically targeted the pseudodimeric structure of the drug transporter and represented a new generation of inhibitors with high transporter binding affinity and low toxicity. This review concerned the recent updates on the structure-activity relationships of flavonoids as P-gp inhibitors, the molecular mechanisms of their action and their ability to overcome P-gp-mediated MDR in preclinical studies. It had crucial implications on the discovery of new drug candidates that modulated the efflux of ABC transporters and also provided some clues for the future development in this promising area.

Targeting PPARalpha in Alzheimer's Disease

2018 ◽  
Vol 15 (4) ◽  
pp. 345-354 ◽  
Author(s):  
Barbara D'Orio ◽  
Anna Fracassi ◽  
Maria Paola Cerù ◽  
Sandra Moreno
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Molecular Mechanisms ◽  
Redox Homeostasis ◽  
Antioxidant Response ◽  
Peroxisome Proliferator ◽  
Prevailing Paradigm

Background: The molecular mechanisms underlying Alzheimer's disease (AD) are yet to be fully elucidated. The so-called “amyloid cascade hypothesis” has long been the prevailing paradigm for causation of disease, and is today being revisited in relation to other pathogenic pathways, such as oxidative stress, neuroinflammation and energy dysmetabolism. The peroxisome proliferator-activated receptors (PPARs) are expressed in the central nervous system (CNS) and regulate many physiological processes, such as energy metabolism, neurotransmission, redox homeostasis, autophagy and cell cycle. Among the three isotypes (α, β/δ, γ), PPARγ role is the most extensively studied, while information on α and β/δ are still scanty. However, recent in vitro and in vivo evidence point to PPARα as a promising therapeutic target in AD. Conclusion: This review provides an update on this topic, focussing on the effects of natural or synthetic agonists in modulating pathogenetic mechanisms at AD onset and during its progression. Ligandactivated PPARα inihibits amyloidogenic pathway, Tau hyperphosphorylation and neuroinflammation. Concomitantly, the receptor elicits an enzymatic antioxidant response to oxidative stress, ameliorates glucose and lipid dysmetabolism, and stimulates autophagy.

Novel Findings of Anti-cancer Property of Propofol

2018 ◽  
Vol 18 (2) ◽  
pp. 156-165 ◽  
Author(s):  
Jiaqiang Wang ◽  
Chien-shan Cheng ◽  
Yan Lu ◽  
Xiaowei Ding ◽  
Minmin Zhu ◽  
...  
Keyword(s):  
General Anesthesia ◽  
Cancer Progression ◽  
Molecular Mechanisms ◽  
Intravenous Anesthetic ◽  
The Past ◽  
Anti Cancer ◽  
Underlying Mechanisms ◽  
Recent Attention

Background: Propofol, a widely used intravenous anesthetic agent, is traditionally applied for sedation and general anesthesia. Explanation: Recent attention has been drawn to explore the effect and mechanisms of propofol against cancer progression in vitro and in vivo. Specifically, the proliferation-inhibiting and apoptosis-inducing properties of propofol in cancer have been studied. However, the underlying mechanisms remain unclear. Conclusion: This review focused on the findings within the past ten years and aimed to provide a general overview of propofol's malignance-modulating properties and the potential molecular mechanisms.

Cardiovascular Effects of Micromeria graeca (L.) Benth. ex Rchb in Normotensive and Hypertensive Rats

2020 ◽  
Vol 20 (8) ◽  
pp. 1253-1261
Author(s):  
Mourad Akdad ◽  
Mohamed Eddouks
Keyword(s):  
Blood Pressure ◽  
Cardiovascular System ◽  
Arterial Blood Pressure ◽  
Antihypertensive Activity ◽  
Computer Assisted ◽  
Hypertensive Rats ◽  
Vasorelaxant Effect ◽  
Arterial Blood

Aims: The present study was performed in order to analyze the antihypertensive activity of Micromeria graeca (L.) Benth. ex Rchb. Background: Micromeria graeca (L.) Benth. ex Rchb is an aromatic and medicinal plant belonging to the Lamiaceae family. This herb is used to treat various pathologies such as cardiovascular disorders. Meanwhile, its pharmacological effects on the cardiovascular system have not been studied. Objective: The present study aimed to evaluate the effect of aqueous extract of aerial parts of Micromeria graeca (AEMG) on the cardiovascular system in normotensive and hypertensive rats. Methods: In this study, the cardiovascular effect of AEMG was evaluated using in vivo and in vitro investigations. In order to assess the acute effect of AEMG on the cardiovascular system, anesthetized L-NAME-hypertensive and normotensive rats received AEMG (100 mg/kg) orally and arterial blood pressure parameters were monitored during six hours. In the sub-chronic study, rats were orally treated for one week, followed by blood pressure assessment during one week of treatment. Blood pressure was measured using a tail-cuff and a computer-assisted monitoring device. In the second experiment, isolated rat aortic ring pre-contracted with Epinephrine (EP) or KCl was used to assess the vasorelaxant effect of AEMG. Results: Oral administration of AEMG (100 mg/kg) provoked a decrease of arterial blood pressure parameters in hypertensive rats. In addition, AEMG induced a vasorelaxant effect in thoracic aortic rings pre-contracted with EP (10 μM) or KCl (80 mM). This effect was attenuated in the presence of propranolol and methylene blue. While in the presence of glibenclamide, L-NAME, nifedipine or Indomethacin, the vasorelaxant effect was not affected. Conclusion: This study showed that Micromeria graeca possesses a potent antihypertensive effect and relaxes the vascular smooth muscle through β-adrenergic and cGMP pathways.

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