scholarly journals TRPML1ng on sparks

2020 ◽  
Vol 13 (637) ◽  
pp. eabc0993
Author(s):  
Madeline Nieves-Cintron ◽  
Luis F. Santana ◽  
Manuel F. Navedo
Keyword(s):  
Blood Pressure ◽  
Ryanodine Receptors ◽  
Permeable Channel ◽  
Functional Studies ◽  
Myocyte Contractility

In this issue of Science Signaling, Thakore et al. report that the Ca2+-permeable channel TRPML1 closely associates with ryanodine receptors to induce Ca2+ sparks in native arterial myocytes. Functional studies revealed a key role for TRPML1 channels in regulation of arterial myocyte contractility and blood pressure.

Abstract 211: Variation of NEDD4L is Associated with Hypertension in Chinese Hans Chronic Kidney Disease Patients

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Cheng Wang ◽  
Jun Zhang ◽  
Cuicui Li ◽  
Wenyu Gong ◽  
Tanqi Lou
Keyword(s):  
Blood Pressure ◽  
Chronic Kidney Disease ◽  
Logistic Regression ◽  
Kidney Disease ◽  
Blood Pressure Monitoring ◽  
Multivariate Logistic Regression Analysis ◽  
Multivariate Logistic Regression ◽  
Functional Studies ◽  
Chi Squared ◽  
The Relationship

Background: Neural precursor cell expressed developmentally down-regulated 4-like (NEDD4L) is a candidate gene for hypertension, and carriers of an intact NEDD4L C2-domain,encoded by the NEDD4L rs4149601 (G/A) GG genotype, together with the C-allele of the NEDD4L rs2288774 (C/T) polymorphism have been found be associated with hypertension both in African Americans and whites. However, there is no data on the relationship between polymorphism of NEDD4L rs4149601 and rs2288774 and hypertension in Chinese chronic kidney disease (CKD) patients. The purpose of the current study was to investigate the relationship between the variation of NEDD4L rs4149601, rs2288774 and hypertension in CKD patients. Methods: A total of 546 Chines Hans CKD patients were enrolled in our study. The SNPs were genotyped using PCR-based techniques. All patients underwent ambulatory blood pressure monitoring, and clinical data were also collected. Multivariate logistic regression analysis was used to identify the relationship between polymorphisms and hypertension. Results: 506 patients carried GG/GA genotype and 30 carried AA genotype. Rs4149601 AA genotype carriers had significantly higher rate of hypertension (68.3% vs 46.2%, P = 0.022) than GG/GA genotype carriers by Chi-squared test. AA genotype carriers also had a higher day-time and bedtime systolic blood pressure (142±16 vs 135±23, P=0.036; 137±18 vs 127±13, P=0.022, respectively) when compared with GG/GA genotype carriers. AA genotype [OR= 3.08, 95% CI (1.06-9.80)], lowever eGFR [OR=0.98, 95% CI (0.97-0.99)], older age [OR=1.03, 95% CI (1.01-1.05)] were independently associated with hypertension in CKD patients by multivariate logistic regression. However, No difference was found in blood pressure with rs2288774 TT/TC/CC genotypes, and no difference was found in the incidence of hypertension among patients with three genotypes. Conclusions: Our results suggested 4149601AA genotype of NEDD4L may be associated with hypertension in CKD patients, and further genetic and functional studies are required to understand its role in the manifestation of hypertension in Chinese CKD patients.

scholarly journals Structural mechanism of two gain-of-function cardiac and skeletal RyR mutations at an equivalent site by cryo-EM

2020 ◽  
Vol 6 (31) ◽  
pp. eabb2964 ◽  
Author(s):  
Kavita A. Iyer ◽  
Yifan Hu ◽  
Ashok R. Nayak ◽  
Nagomi Kurebayashi ◽  
Takashi Murayama ◽  
...  
Keyword(s):  
Single Point ◽  
Ryanodine Receptors ◽  
Point Mutations ◽  
Salt Bridge ◽  
Structural Effect ◽  
Protein Loss ◽  
Structural Mechanism ◽  
Functional Studies ◽  
Equivalent Site ◽  
Intracellular Ca

Mutations in ryanodine receptors (RyRs), intracellular Ca2+ channels, are associated with deadly disorders. Despite abundant functional studies, the molecular mechanism of RyR malfunction remains elusive. We studied two single-point mutations at an equivalent site in the skeletal (RyR1 R164C) and cardiac (RyR2 R176Q) isoforms using ryanodine binding, Ca2+ imaging, and cryo–electron microscopy (cryo-EM) of the full-length protein. Loss of the positive charge had greater effect on the skeletal isoform, mediated via distortion of a salt bridge network, a molecular latch inducing rotation of a cytoplasmic domain, and partial progression to open-state traits of the large cytoplasmic assembly accompanied by alteration of the Ca2+ binding site, which concur with the major “hyperactive” feature of the mutated channel. Our cryo-EM studies demonstrated the allosteric effect of a mutation situated ~85 Å away from the pore and identified an isoform-specific structural effect.

Gene transfer of a novel vasoactive natriuretic peptide stimulates cGMP and lowers blood pressure in mice

2004 ◽  
Vol 286 (6) ◽  
pp. H2213-H2218 ◽  
Author(s):  
Shuchong Pan ◽  
Rajiv Gulati ◽  
Cheryl S. Mueske ◽  
Tyra A. Witt ◽  
Amir Lerman ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Gene Transfer ◽  
Natriuretic Peptide ◽  
First Generation ◽  
Conditioned Media ◽  
Peptide Sequence ◽  
Physiological Effects ◽  
Dendroaspis Angusticeps ◽  
Functional Studies ◽  
Cardiovascular Therapeutics

Dendroaspis natriuretic peptide (DNP) is a recently described peptide produced by Dendroaspis angusticeps with structural and functional similarities to mammalian natriuretic peptides. These similarities suggest a potential role for DNP in cardiovascular therapeutics. To determine the physiological effects of chronic delivery of DNP, a gene transfer approach using first generation adenoviral vectors was utilized. Although the gene for DNP has not been cloned in any species, the peptide sequence in the snake is known. Preferred mammalian codons for snake DNP were cloned downstream of either the leader sequence (referred to as pBDNP-1) or prepropeptide sequence of human brain natriuretic peptide (BNP) cDNA (referred to as pBDNP-2). Transfections with pBDNP-1 or pBDNP-2 resulted in expected forms of chimeric DNP (cDNP) in cell lysates and conditioned media. Functional studies demonstrated the ability of both forms of cDNP within conditioned media to stimulate cGMP production in human vascular smooth muscle cells (hVSMC). Expressed cDNP inhibited hVSMC proliferation and stimulated vasorelaxation in a similar fashion. To investigate the chronic physiological effects of administration of cDNP, an adenoviral vector expressing cDNP (Ad-BDNP) was generated. Intravenous delivery of Ad-BDNP in mice resulted in dose-dependent systemic expression of cDNP. The highest level of expression was associated with consistent elevation of its presumed second messenger (cGMP) for 21 days but with transient lowering of systolic blood pressure in normotensive mice. This study demonstrates the biological features of the expression of the xenogenic peptide DNP.

scholarly journals Cryo-EM reveals local and global structural rearrangements in RYR mutants

2021 ◽  
Vol 154 (9) ◽  
Author(s):  
Kavita A. Iyer ◽  
Yifan Hu ◽  
Thomas Klose ◽  
Takashi Murayama ◽  
Montserrat Samsó
Keyword(s):  
Long Range ◽  
Conformational Changes ◽  
Large Scale ◽  
Single Point ◽  
Ryanodine Receptors ◽  
Critical Role ◽  
Point Mutations ◽  
Polymorphic Ventricular Tachycardia ◽  
Functional Studies ◽  
Single Point Mutations

Single-point mutations in ryanodine receptors (RYRs), large intracellular Ca2+ channels that play a critical role in EC coupling, are linked to debilitating and lethal disorders such as central core disease, malignant hyperthermia (for the skeletal isoform, RYR1), catecholaminergic polymorphic ventricular tachycardia, and ARVD2 (for the cardiac isoform, RYR2). Mutant RYRs result in elevated [Ca2+]cyto due to steady leak from the sarcoplasmic reticulum. To explore the nature of long-range allosteric mechanisms of malfunction, we determined the structure of two N-terminal domain mutants of RYR1, situated far away from the pore. Cryo-electron microscopy of the N-terminal subdomain A (NTDA) and subdomain C (NTDC) full-length mutants, RYR1 R163C (determined to 3.5 Å resolution), and RYR1 Y522S (determined to 4.0 Å resolution), respectively, reveal large-scale conformational changes in the cytoplasmic assembly under closed-state conditions (i.e., absence of activating Ca2+). The multidomain changes suggest that the mutations induce a preactivated state of the channel in R164C by altering the NTDA+/CD interface, and in Y522S by rearrangement of the α-helical bundle in NTDC. However, the extent of preactivation is considerably higher in Y522S as compared with R163C, which agrees with the increased severity of the Y522S mutation as established by various functional studies. The Y522S mutation represents loss of a spacer residue that is crucial for maintaining optimal orientation of α helices in NTDC, alteration of which has long-range effects felt as far away as ∼100 Å. Additionally, the structure of the Y522S mutant channel under open-state conditions also differs from RYR1 WT open channels. Our developing work with RYR mutants exhibits the diverse mechanisms by which these single-point mutations exert an effect on the channel’s function and highlight the complexity of the multidomain channel, as well as the need for targeted therapies.

Renal medullary genes in salt-sensitive hypertension: a chromosomal substitution and cDNA microarray study

2002 ◽  
Vol 8 (2) ◽  
pp. 139-149 ◽  
Author(s):  
Mingyu Liang ◽  
Baozhi Yuan ◽  
Elizabeth Rute ◽  
Andrew S. Greene ◽  
Ai-Ping Zou ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cdna Microarray ◽  
Expression Profiles ◽  
Substantial Reduction ◽  
Renal Medulla ◽  
Differentially Expressed ◽  
Brown Norway ◽  
Functional Studies ◽  
Rat Strain ◽  
Salt Sensitive Hypertension

Substitution of chromosome 13 from Brown Norway BN/SsNHsd/Mcw (BN/Mcw) rats into the Dahl salt-sensitive SS/JrHsd/Mcw (SS/Mcw) rats resulted in substantial reduction of blood pressure salt sensitivity in this consomic rat strain designated SSBN13. In the present study, we attempted to identify genes associated with salt-sensitive hypertension by utilizing a custom, known-gene cDNA microarray to compare the mRNA expression profiles in the renal medulla (a tissue playing a pivotal role in long-term blood pressure regulation) of SS/Mcw and SSBN13 rats on either low-salt (0.4% NaCl) or high-salt (4% NaCl, 2 wk) diets. To increase the reliability of microarray data, we designed a four-way comparison experiment incorporating several levels of replication and developed a conservative yet robust data analysis method. Using this approach, from the 1,751 genes examined (representing more than 80% of all currently known rat genes), we identified 80 as being differentially expressed in at least 1 of the 4 comparisons. Substantial agreements were found between the microarray results and the results predicted on the basis of the four-way comparison as well as the results of Northern blots of 20 randomly selected genes. Analysis of the four-way comparison further indicated that ∼75% of the 80 differentially expressed genes were likely related to salt-sensitive hypertension. Many of these genes had not previously been recognized to be important in hypertension, whereas several genes/pathways known to be involved in hypertension were confirmed. These results should provide an informative source for designing future functional studies in salt-sensitive hypertension.

Increased ganglionic responses to substance P in hypertensive rats due to upregulation of NK1 receptors

2000 ◽  
Vol 279 (5) ◽  
pp. R1685-R1694 ◽  
Author(s):  
Robert V. Schoborg ◽  
Donald B. Hoover ◽  
John D. Tompkins ◽  
John C. Hancock
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Substance P ◽  
Intravenous Injection ◽  
Pressor Response ◽  
Sympathetic Ganglia ◽  
Hypertensive Rats ◽  
Renal Nerve ◽  
Functional Studies ◽  
Wistar Kyoto

Intravenous injection of substance P (SP) increases renal nerve firing and heart rate in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats (WKYs) by stimulating sympathetic ganglia. Blood pressure is increased in SHRs but lowered in WKYs. This study assesses the role of neurokinin-1 (NK1) receptors in mediating the ganglion actions of SP. Rats for functional studies were anesthetized and then treated with chlorisondamine. Renal nerve, blood pressure, and heart rate responses to intravenous injection of the NK1 receptor agonist GR-73632 were similar but less than those to equimolar doses of SP in SHRs. GR-73632 only slightly increased renal nerve firing and heart rate and lowered blood pressure in WKYs. The NK1receptor antagonist GR-82334 (200 nmol/kg iv) blocked the ganglionic actions of GR-73632 and the pressor response to SP in SHRs. It reduced the renal nerve and heart rate responses by 52 and 35%. This suggests that the pressor response to SP is mediated by ganglionic NK1 receptors and that NK1 receptors also have a prominent role in mediating the renal nerve and heart rate responses to SP. Quantitative autoradiography showed that NK1receptors are more abundant in the superior cervical ganglia of SHRs. RT-PCR showed increased abundance of NK1 receptor mRNA in SHRs as well. These observations suggest that the greater ganglionic stimulation caused by SP in SHRs is due to upregulation of NK1 receptors.

scholarly journals Endothelial SK3 channel-associated Ca2+ microdomains modulate blood pressure

2016 ◽  
Vol 310 (9) ◽  
pp. H1151-H1163 ◽  
Author(s):  
Fui C. Yap ◽  
David S. Weber ◽  
Mark S. Taylor ◽  
Mary I. Townsley ◽  
Brian S. Comer ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Distinct Type ◽  
Transient Receptor Potential Channels ◽  
Mesenteric Arteries ◽  
Functional Studies ◽  
Real Time Quantitative Pcr ◽  
Electrophysiological Recordings ◽  
Sk3 Channel

Activation of vascular endothelial small- (KCa2.3, SK3) or intermediate- (KCa3.1, IK1) conductance Ca2+-activated potassium channels induces vasorelaxation via an endothelium-derived hyperpolarization (EDH) pathway. Although the activation of SK3 and IK1 channels converges on EDH, their subcellular effects on signal transduction are different and not completely clear. In this study, a novel endothelium-specific SK3 knockout (SK3−/−) mouse model was utilized to specifically examine the contribution of SK3 channels to mesenteric artery vasorelaxation, endothelial Ca2+ dynamics, and blood pressure. The absence of SK3 expression was confirmed using real-time quantitative PCR and Western blot analysis. Functional studies showed impaired EDH-mediated vasorelaxation in SK3−/− small mesenteric arteries. Immunostaining results from SK3−/− vessels confirmed the absence of SK3 and further showed altered distribution of transient receptor potential channels, type 4 (TRPV4). Electrophysiological recordings showed a lack of SK3 channel activity, while TRPV4-IK1 channel coupling remained intact in SK3−/− endothelial cells. Moreover, Ca2+ imaging studies in SK3−/− endothelium showed increased Ca2+ transients with reduced amplitude and duration under basal conditions. Importantly, SK3−/− endothelium lacked a distinct type of Ca2+ dynamic that is sensitive to TRPV4 activation. Blood pressure measurements showed that the SK3−/− mice were hypertensive, and the blood pressure increase was further enhanced during the 12-h dark cycle when animals are most active. Taken together, our results reveal a previously unappreciated SK3 signaling microdomain that modulates endothelial Ca2+ dynamics, vascular tone, and blood pressure.

scholarly journals Decreased cardiac pacemaking and attenuated β-adrenergic response in TRIC-A knockout mice

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244254
Author(s):  
Manabu Murakami ◽  
Yuichi Toyama ◽  
Manabu Yonekura ◽  
Takayoshi Ohba ◽  
Yasushi Matsuzaki ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Rhythm ◽  
Calcium Release ◽  
Sinus Node ◽  
Ryanodine Receptors ◽  
Regulatory System ◽  
Adrenergic Stimulation ◽  
Physiological Importance ◽  
Cardiac Pacemaking ◽  
Sympathetic Responses

Changes in intracellular calcium levels in the sinus node modulate cardiac pacemaking (the calcium clock). Trimeric intracellular cation (TRIC) channels are counterion channels on the surface of the sarcoplasmic reticulum and compensate for calcium release from ryanodine receptors, which play a major role in calcium-induced calcium release (CICR) and the calcium clock. TRIC channels are expected to affect the calcium clock in the sinus node. However, their physiological importance in cardiac rhythm formation remains unclear. We evaluated the importance of TRIC channels on cardiac pacemaking using TRIC-A-null (TRIC-A–/–) as well as TRIC-B+/–mice. Although systolic blood pressure (SBP) was not significantly different between wild-type (WT), TRIC-B+/–, and TRIC-A–/–mice, heart rate (HR) was significantly lower in TRIC-A–/–mice than other lines. Interestingly, HR and SBP showed a positive correlation in WT and TRIC-B+/–mice, while no such correlation was observed in TRIC-A–/–mice, suggesting modification of the blood pressure regulatory system in these mice. Isoproterenol (0.3 mg/kg) increased the HR in WT mice (98.8 ± 15.1 bpm), whereas a decreased response in HR was observed in TRIC-A–/–mice (23.8 ± 5.8 bpm), suggesting decreased sympathetic responses in TRIC-A–/–mice. Electrocardiography revealed unstable R-R intervals in TRIC-A–/–mice. Furthermore, TRIC-A–/–mice sometimes showed sinus pauses, suggesting a significant role of TRIC-A channels in cardiac pacemaking. In isolated atrium contraction or action potential recording, TRIC-A–/–mice showed decreased response to a β-adrenergic sympathetic nerve agonist (isoproterenol, 100 nM), indicating decreased sympathetic responses. In summary, TRIC-A–/–mice showed decreased cardiac pacemaking in the sinus node and attenuated responses to β-adrenergic stimulation, indicating the involvement of TRIC-A channels in cardiac rhythm formation and decreased sympathetic responses.

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