Peptide Blocking Self-Polymerization of Extracellular Calcium-Sensing Receptor Attenuates Hypoxia-Induced Pulmonary Hypertension

Hypertension ◽  
2021 ◽  
Author(s):  
Rui Xiao ◽  
Shengquan Luo ◽  
Ting Zhang ◽  
Yankai Lv ◽  
Tao Wang ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Disulfide Bonds ◽  
Acute Hypoxia ◽  
Extracellular Domain ◽  
Left Ventricular ◽  
Extracellular Calcium ◽  
Calcium Sensing Receptor ◽  
Calcium Sensing

Activation of the CaSR (extracellular calcium-sensing receptor) has been recognized as a critical mediator of hypoxia-induced pulmonary hypertension. Preventive targeting of the early initiating phase as well as downstream events after CaSR activation remains unexplored. As a representative of the G protein-coupled receptor family, CaSR polymerizes on cell surface upon stimulation. Immunoblotting together with MAL-PEG technique identified a reactive oxygen species-sensitive CaSR polymerization through its extracellular domain in pulmonary artery smooth muscle cells upon exposure to acute hypoxia. Fluorescence resonance energy transfer screening employing blocking peptides determined that cycteine129/131 residues in the extracellular domain of CaSR formed intermolecular disulfide bonds to promote CaSR polymerization. The monitoring of intracellular Ca 2+ signal highlighted the pivotal role of CaSR polymerization in its activation. In contrast, the blockade of disulfide bonds formation using a peptide decreased both CaSR and hypoxia-induced mitogenic factor expression as well as other hypoxic-related genes in vitro and in vivo and attenuated pulmonary hypertension development in rats. The blocking peptide did not affect systemic arterial oxygenation in vivo but inhibited acute hypoxia-induced pulmonary vasoconstriction. Pharmacokinetic analyses revealed a more efficient lung delivery of peptide by inhaled nebulizer compared to intravenous injection. In addition, the blocking peptide did not affect systemic arterial pressure, body weight, left ventricular function, liver, or kidney function or plasma Ca 2+ level. In conclusion, a peptide blocking CaSR polymerization reduces its hypoxia-induced activation and downstream events leading to pulmonary hypertension and represents an attractive inhaled preventive alternative worthy of further development.

scholarly journals The Extracellular Calcium-Sensing Receptor Regulates the Proliferation of Colonic Epithelial Cells In Vitro and In Vivo

2011 ◽  
Vol 140 (5) ◽  
pp. S-482
Author(s):  
Osvaldo Rey ◽  
Wenhan Chang ◽  
Daniel Bikle ◽  
Nora Rozengurt ◽  
Mary P. Moyer ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Extracellular Calcium ◽  
Calcium Sensing Receptor ◽  
Colonic Epithelial Cells ◽  
Calcium Sensing

Mice deficient in galectin-1 exhibit attenuated physiological responses to chronic hypoxia-induced pulmonary hypertension

2007 ◽  
Vol 292 (1) ◽  
pp. L154-L164 ◽  
Author(s):  
D. Case ◽  
D. Irwin ◽  
C. Ivester ◽  
J. Harral ◽  
K. Morris ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Right Ventricular ◽  
Chronic Hypoxia ◽  
Acute Hypoxia ◽  
Left Ventricular ◽  
Wild Type ◽  
Ph Response ◽  
Subtractive Library

Pulmonary hypertension (PH) is characterized by sustained vasoconstriction, with subsequent extracellular matrix (ECM) production and smooth muscle cell (SMC) proliferation. Changes in the ECM can modulate vasoreactivity and SMC contraction. Galectin-1 (Gal-1) is a hypoxia-inducible β-galactoside-binding lectin produced by vascular, interstitial, epithelial, and immune cells. Gal-1 regulates SMC differentiation, proliferation, and apoptosis via interactions with the ECM, as well as immune system function, and, therefore, likely plays a role in the pathogenesis of PH. We investigated the effects of Gal-1 during hypoxic PH by quantifying 1) Gal-1 expression in response to hypoxia in vitro and in vivo and 2) the effect of Gal-1 gene deletion on the magnitude of the PH response to chronic hypoxia in vivo. By constructing and screening a subtractive library, we found that acute hypoxia increases expression of Gal-1 mRNA in isolated pulmonary mesenchymal cells. In wild-type (WT) mice, Gal-1 immunoreactivity increased after 6 wk of hypoxia. Increased expression of Gal-1 protein was confirmed by quantitative Western analysis. Gal-1 knockout (Gal-1−/−) mice showed a decreased PH response, as measured by right ventricular pressure and the ratio of right ventricular to left ventricular + septum wet weight compared with their WT counterparts. However, the number and degree of muscularized vessels increased similarly in WT and Gal-1−/− mice. In response to chronic hypoxia, the decrease in factor 8-positive microvessel density was similar in both groups. Vasoreactivity of WT and Gal-1−/− mice was tested in vivo and with use of isolated perfused lungs exposed to acute hypoxia. Acute hypoxia caused a significant increase in RV pressure in wild-type and Gal-1−/− mice; however, the response of the Gal-1−/− mice was greater. These results suggest that Gal-1 influences the contractile response to hypoxia and subsequent remodeling during hypoxia-induced PH, which influences disease progression.

scholarly journals Calcium-Sensing Receptor and Aquaporin 2 Interplay in Hypercalciuria-Associated Renal Concentrating Defect in Humans. An In Vivo and In Vitro Study

PLoS ONE ◽  
2012 ◽  
Vol 7 (3) ◽  
pp. e33145 ◽  
Author(s):  
Giuseppe Procino ◽  
Lisa Mastrofrancesco ◽  
Grazia Tamma ◽  
Domenica Rita Lasorsa ◽  
Marianna Ranieri ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Vitro Study ◽  
Calcium Sensing Receptor ◽  
Aquaporin 2 ◽  
Calcium Sensing ◽  
Concentrating Defect

Calcium-sensing receptor (CASR) is involved in porcine in vitro fertilisation and early embryo development

2018 ◽  
Vol 30 (2) ◽  
pp. 391 ◽  
Author(s):  
C. Liu ◽  
Y. Liu ◽  
K. Larsen ◽  
Y. P. Hou ◽  
H. Callesen
Keyword(s):  
Embryo Development ◽  
Early Embryo ◽  
Extracellular Calcium ◽  
In Vitro Fertilisation ◽  
Control Group ◽  
Blastocyst Formation ◽  
Calcium Sensing Receptor ◽  
Early Embryo Development ◽  
Calcium Sensing

It has been demonstrated that extracellular calcium is necessary in fertilisation and embryo development but the mechanism is still not well understood. The present study mainly focussed on the extracellular calcium effector called the calcium-sensing receptor (CASR) and examined its expression in porcine gametes and embryos and its function during fertilisation and early embryo development. By using reverse transcription polymerase chain reaction, CASR was found to be expressed in porcine oocytes, spermatozoa and embryos at different developmental stages. Functionally, medium supplementation with a CASR agonist or an antagonist during in vitro fertilisation (IVF) and in vitro culture (IVC) was tested. During fertilisation, the presence of a CASR agonist increased sperm penetration rate and decreased polyspermy rate leading to an increased normal fertilisation rate. During embryo development, for the IVF embryos, agonist treatment during IVC significantly increased cleavage rate and blastocyst formation rate compared with the control group. Furthermore, parthenogenetically activated embryos showed similar results with lower cleavage and blastocyst formation rates in the antagonist group than in the other groups. It was concluded that CASR, as the effector of extracellular calcium, modulates porcine fertilisation and early embryo development.

scholarly journals Kokumi taste perception is functional in a model carnivore, the domestic cat (Felis catus)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Laffitte ◽  
M. Gibbs ◽  
C. Hernangomez de Alvaro ◽  
J. Addison ◽  
Z. N. Lonsdale ◽  
...  
Keyword(s):  
Amino Acids ◽  
Taste Receptor ◽  
Felis Catus ◽  
Domestic Cat ◽  
Taste Perception ◽  
Ligand Specificity ◽  
Calcium Sensing Receptor ◽  
Calcium Sensing

AbstractKokumi taste is a well-accepted and characterised taste modality and is described as a sensation of enhancement of sweet, salty, and umami tastes. The Calcium Sensing Receptor (CaSR) has been designated as the putative kokumi taste receptor for humans, and a number of kokumi-active ligands of CaSR have been discovered recently with activity confirmed both in vivo and in vitro. Domestic cats (Felis catus) are obligate carnivores and accordingly, their diet is abundant in proteins, peptides, and amino acids. We hypothesised that CaSR is a key taste receptor for carnivores, due to its role in the detection of different peptides and amino acids in other species. Using in silico, in vitro and in vivo approaches, here we compare human CaSR to that of a model carnivore, the domestic cat. We found broad similarities in ligand specificity, but differences in taste sensitivity between the two species. Indeed our in vivo data shows that cats are sensitive to CaCl2 as a kokumi compound, but don’t show this same activity with Glutathione, whereas for humans the reverse is true. Collectively, our data suggest that kokumi is an important taste modality for carnivores that drives the palatability of meat-derived compounds such as amino acids and peptides, and that there are differences in the perception of kokumi taste between carnivores and omnivores.

scholarly journals Effects of pharmacological calcimimetics on colorectal cancer cells over-expressing the human calcium-sensing receptor

2020 ◽  
Author(s):  
Luca Iamartino ◽  
Taha Elajnaf ◽  
Katharina Gall ◽  
Jacquelina David ◽  
Teresa Manhardt ◽  
...  
Keyword(s):  
Gene Expression ◽  
Colorectal Cancer ◽  
Tumor Growth ◽  
Colorectal Carcinogenesis ◽  
Inflammatory Factors ◽  
Type Ii ◽  
Calcium Sensing Receptor ◽  
Calcium Sensing

AbstractThe calcium-sensing receptor (CaSR) is a ubiquitously expressed multifunctional G protein-coupled receptor. Several studies reported that the CaSR plays an anti-inflammatory and anti-tumorigenic role in the intestine, and that it is down-regulated during colorectal carcinogenesis. We hypothesized that intestine-specific positive allosteric CaSR modulators (type II calcimimetics) could be used for the treatment of intestinal pathologies. Therefore, the aim of this study was to determine the effect of pharmacological stimulation of CaSR on gene expression in vitro and on tumor growth in vivo.We stably transduced two colon cancer cell lines (HT29 and Caco2) with lentiviral vectors containing either the CaSR fused to GFP or GFP only. Using RNA sequencing, RT-qPCR experiments and ELISA, we determined that CaSR over-expression itself had generally little effect on gene expression in these cells. However, treatment with 1μM of the calcimimetic NPS R-568 increased the expression of pro-inflammatory factors such as IL-23α and IL-8 and reduced the transcription of various differentiation markers in the cells over-expressing the CaSR. In vivo, neither the presence of the CaSR nor p.o. treatment of the animals with the calcimimetic cinacalcet affected tumor growth, tumor cell proliferation or tumor vascularization of murine HT29 xenografts.In summary, CaSR stimulation in CaSR over-expressing cells enhanced the expression of inflammatory markers in vitro, but was not able to repress colorectal cancer tumorigenicity in vivo. These findings suggest potential pro-inflammatory effects of the CaSR and type II calcimimetics in the intestine.

scholarly journals Determination and Modulation of Total and Surface Calcium-Sensing Receptor Expression in Monocytes In Vivo and In Vitro

PLoS ONE ◽  
2013 ◽  
Vol 8 (10) ◽  
pp. e74800 ◽  
Author(s):  
Julien Paccou ◽  
Cédric Boudot ◽  
Aurélien Mary ◽  
Said Kamel ◽  
Tilman Bernhard Drüeke ◽  
...  
Keyword(s):  
Receptor Expression ◽  
Calcium Sensing Receptor ◽  
Calcium Sensing

scholarly journals Exposure of mice to chronic hypoxia attenuates pulmonary arterial contractile responses to acute hypoxia by increases in extracellular hydrogen peroxide

2014 ◽  
Vol 307 (4) ◽  
pp. R426-R433 ◽  
Author(s):  
Dhara Patel ◽  
Raed Alhawaj ◽  
Michael S. Wolin
Keyword(s):  
Hydrogen Peroxide ◽  
Pulmonary Hypertension ◽  
Chronic Hypoxia ◽  
Soluble Guanylate Cyclase ◽  
Aminolevulinic Acid ◽  
Acute Hypoxia ◽  
Pulmonary Arteries ◽  
Protoporphyrin Ix

Exposing mice to a chronic hypoxic treatment (10% oxygen, 21 days) that promotes pulmonary hypertension was observed to attenuate the pulmonary vasoconstriction response to acute hypoxia (HPV) both in vivo and in isolated pulmonary arteries. Since catalase restored the HPV response in isolated arteries, it appeared to be attenuated by extracellular hydrogen peroxide. Chronic hypoxia promoted the detection of elevated lung superoxide, extracellular peroxide, extracellular SOD expression, and protein kinase G (PKG) activation [based on PKG dimerization and vasodilator-stimulated phosphoprotein (VASP) phosphorylation], suggesting increased generation of extracellular peroxide and PKG activation may contribute to the suppression of HPV. Aorta from mice exposed to 21 days of hypoxia also showed evidence for extracellular hydrogen peroxide, suppressing the relaxation response to acute hypoxia. Peroxide appeared to partially suppress contractions to phenylephrine used in the study of in vitro hypoxic responses. Treatment of mice with the heme precursor δ-aminolevulinic acid (ALA; 50 mg·kg−1·day−1) during exposure to chronic hypoxia was examined as a pulmonary hypertension therapy because it could potentially activate beneficial cGMP-mediated effects through promoting a prolonged protoporphyrin IX (PpIX)-elicited activation of soluble guanylate cyclase. ALA attenuated pulmonary hypertension, increases in both superoxide and peroxide, and the suppression of in vitro and in vivo HPV responses. ALA generated prolonged detectible increases in PpIX and PKG-associated phosphorylation of VASP, suggesting PKG activation may contribute to suppression of pulmonary hypertension and prevention of alterations in extracellular peroxide that appear to be attenuating HPV responses caused by chronic hypoxia.

ID: 119: PATHOGENIC ROLES OF CALCIUM-SENSING RECEPTORS AND TRANSIENT RECEPTOR POTENTIAL CANONICAL CHANNELS 6 IN THE DEVELOPMENT AND PROGRESSION OF PULMONARY HYPERTENSION

2016 ◽  
Vol 64 (4) ◽  
pp. 967.3-968
Author(s):  
H TANG ◽  
Y Gu ◽  
SM Black ◽  
JG Garcia ◽  
A Makino ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Transient Receptor Potential ◽  
Acute Hypoxia ◽  
New Drugs ◽  
Calcium Sensing ◽  
Pulmonary Vasoconstriction ◽  
Pulmonary Arterial

RationalAn increase [Ca2+]cyt in pulmonary arterial smooth muscle cells (PASMC) is a major trigger for pulmonary vasoconstriction and a critical stimulation for PASMC proliferation and migration. We previously demonstrated that expression and function of calcium sensing receptors (CaSR) in PASMC from patients with idiopathic pulmonary arterial hypertension (IPAH) and animals with experimental pulmonary hypertension (PH) were greater than in PASMC from normal subjects and control animals. However, the mechanisms by which CaSR triggers Ca2+ influx in PASMC and the implication of CaSR in the development of PH remain elusive.ObjectiveTo test the hypothesis that CaSR functionally interacts with TRPC6 to regulate [Ca2+]cyt in PASMC in the development of pulmonary hypertension.Methods and ResultsDownregulation of CaSR or TRPC6 with siRNA inhibited Ca2+-induced [Ca2+]cyt increase in IPAH-PASMC (in which CaSR is upregulated), while overexpression of CaSR or TRPC6 enhanced Ca2+-induced [Ca2+]cyt increase in normal PASMC (in which CaSR expression level is low). The upregulated CaSR in IPAH-PASMC was also associated with enhanced Akt phosphorylation, while blockade of CaSR in IPAH-PASMC attenuated cell proliferation. In in vivo experiments, deletion of the CaSR gene in mice (casr−/−) significantly inhibited the development and progression of experimental PH and markedly attenuated acute hypoxia-induced pulmonary vasoconstriction.ConclusionsThese data indicate that functional interaction of upregulated CaSR and upregulated TRPC6 in PASMC from IPAH patients and animals with experimental PH may play an important role in the development and progression of sustained pulmonary vasoconstriction and pulmonary vascular remodeling. Blockade or downregulation of CaSR and/or TRPC6 with siRNA or miRNA may be a novel therapeutic strategy to develop new drugs for patients with pulmonary arterial hypertension.KeywordsG protein-coupled receptor; ionic ligand; hypoxia-induced pulmonary hypertension.

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