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Arterial Expression of the Calcium-Sensing Receptor Is Maintained by Physiological Pulsation and Protects against Calcification.

Molostvov G, Hiemstra TF, Fletcher S, Bland R, Zehnder D - PLoS ONE (2015)

Bottom Line: Vascular calcification (VC) is common in chronic kidney disease (CKD) and contributes to cardiovascular mortality.High extracellular calcium reduced CaSR expression and promoted osteochondrogenic transformation and calcium deposition.In arterial explants from CKD patients (n = 11) and controls (n = 9), exposure to R568 did not significantly alter calcium deposition, osteochondrogenic markers or total artery calcium content. physiological mechanical strain is important for arterial homeostasis and may protect arteries from VC.

View Article: PubMed Central - PubMed

Affiliation: The Clinical Sciences Research Laboratory, Warwick Medical School, University of Warwick, Coventry, United Kingdom.

ABSTRACT

Unlabelled: Vascular calcification (VC) is common in chronic kidney disease (CKD) and contributes to cardiovascular mortality. The calcium-sensing receptor (CaSR) is present in human artery, senses extracellular calcium and may directly modulate VC.

Objective: to investigate the association between arterial cyclic strain, CaSR expression and VC.

Methods and results: human aortic smooth muscle cells (HAoSMC) were cultured under static or strained conditions, with exposure to CaSR agonists, the calcimimetic R568, and after CaSR silencing and over-expression. High extracellular calcium reduced CaSR expression and promoted osteochondrogenic transformation and calcium deposition. This was partially prevented by cyclic strain and exposure to R568. CaSR silencing enhanced calcification and osteochondrogenic transformation, whereas CaSR over-expression attenuated this procalcific response, demonstrating a central role for the CaSR in the response to cyclic strain and regulation of VC. In arterial explants from CKD patients (n = 11) and controls (n = 9), exposure to R568 did not significantly alter calcium deposition, osteochondrogenic markers or total artery calcium content.

Conclusions: physiological mechanical strain is important for arterial homeostasis and may protect arteries from VC. The beneficial effects of cyclic strain may be mediated via the CaSR.

No MeSH data available.


Related in: MedlinePlus

Effect of CaSR silencing on HAoSMC calcification and phenotype.A) Calcium deposition (measured by alizarin red, n = 4 per condition, logarithmic y-axis) was significantly higher after CaSR silencing in Ca5, Gd and Gd2+Ca2 HAoSMC. B) Representative photographs of alizarin red staining (magnification x100). C) OC expression (n = 5 per condition) was significantly increased by CaSR knockdown across all conditions (Control p = 0.004; Ca2 p = 0.004; Ca5 p = 0.0003; Gd p = 0.0003; Gd+Ca2 p = 0.0001). D) ALP activity (n = 4 per condition) was significantly higher with CaSR silencing compared to control in the presence of Gadolinium (Gd, p = 0.0005; Gd+Ca2, p = 0.01). OC–osteocalcin; ALP–alkaline phosphatase; CaSR–calcium-sensing receptor.
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pone.0138833.g002: Effect of CaSR silencing on HAoSMC calcification and phenotype.A) Calcium deposition (measured by alizarin red, n = 4 per condition, logarithmic y-axis) was significantly higher after CaSR silencing in Ca5, Gd and Gd2+Ca2 HAoSMC. B) Representative photographs of alizarin red staining (magnification x100). C) OC expression (n = 5 per condition) was significantly increased by CaSR knockdown across all conditions (Control p = 0.004; Ca2 p = 0.004; Ca5 p = 0.0003; Gd p = 0.0003; Gd+Ca2 p = 0.0001). D) ALP activity (n = 4 per condition) was significantly higher with CaSR silencing compared to control in the presence of Gadolinium (Gd, p = 0.0005; Gd+Ca2, p = 0.01). OC–osteocalcin; ALP–alkaline phosphatase; CaSR–calcium-sensing receptor.

Mentions: To determine whether HAoSMC calcification was dependent upon CaSR expression, we first compared calcium deposition in HAoSMC after CaSR silencing to that observed under control conditions. We had previously demonstrated that CaSR knockdown resulted in 60–80% decrease in CaSR expression in HAoSMC over 7 days [21,22], and employed the same approach. Consistent with our earlier findings (above), calcification was virtually absent in control and Ca2 HAoSMC, and this was not altered by CaSR silencing. However, under conditions we have previously observed significant calcium deposition (Ca5, Gd, Gd+Ca2), CaSR silencing resulted in further significant increases in calcium deposition. Ca5 CaSR knockdown cells exhibited 70% calcification (95%CI 62–78), increased from 49% (95%CI 38–59) in Ca5 controls (p = 0.002), whereas both Gd CaSR knockdown (5.8, 95%CI 4.1–7.4 versus 2.7, 95%CI 1.7–3.8, p = 0.003) and Gd+Ca2 CaSR knockdown (5.0, 95%CI 3.0–6.9 versus 3.3, 95%CI 2.4–4.1, p = 0.046) HAoSMC also demonstrated significant but lesser increases in calcium deposition (Fig 2A and 2B).


Arterial Expression of the Calcium-Sensing Receptor Is Maintained by Physiological Pulsation and Protects against Calcification.

Molostvov G, Hiemstra TF, Fletcher S, Bland R, Zehnder D - PLoS ONE (2015)

Effect of CaSR silencing on HAoSMC calcification and phenotype.A) Calcium deposition (measured by alizarin red, n = 4 per condition, logarithmic y-axis) was significantly higher after CaSR silencing in Ca5, Gd and Gd2+Ca2 HAoSMC. B) Representative photographs of alizarin red staining (magnification x100). C) OC expression (n = 5 per condition) was significantly increased by CaSR knockdown across all conditions (Control p = 0.004; Ca2 p = 0.004; Ca5 p = 0.0003; Gd p = 0.0003; Gd+Ca2 p = 0.0001). D) ALP activity (n = 4 per condition) was significantly higher with CaSR silencing compared to control in the presence of Gadolinium (Gd, p = 0.0005; Gd+Ca2, p = 0.01). OC–osteocalcin; ALP–alkaline phosphatase; CaSR–calcium-sensing receptor.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4593585&req=5

pone.0138833.g002: Effect of CaSR silencing on HAoSMC calcification and phenotype.A) Calcium deposition (measured by alizarin red, n = 4 per condition, logarithmic y-axis) was significantly higher after CaSR silencing in Ca5, Gd and Gd2+Ca2 HAoSMC. B) Representative photographs of alizarin red staining (magnification x100). C) OC expression (n = 5 per condition) was significantly increased by CaSR knockdown across all conditions (Control p = 0.004; Ca2 p = 0.004; Ca5 p = 0.0003; Gd p = 0.0003; Gd+Ca2 p = 0.0001). D) ALP activity (n = 4 per condition) was significantly higher with CaSR silencing compared to control in the presence of Gadolinium (Gd, p = 0.0005; Gd+Ca2, p = 0.01). OC–osteocalcin; ALP–alkaline phosphatase; CaSR–calcium-sensing receptor.
Mentions: To determine whether HAoSMC calcification was dependent upon CaSR expression, we first compared calcium deposition in HAoSMC after CaSR silencing to that observed under control conditions. We had previously demonstrated that CaSR knockdown resulted in 60–80% decrease in CaSR expression in HAoSMC over 7 days [21,22], and employed the same approach. Consistent with our earlier findings (above), calcification was virtually absent in control and Ca2 HAoSMC, and this was not altered by CaSR silencing. However, under conditions we have previously observed significant calcium deposition (Ca5, Gd, Gd+Ca2), CaSR silencing resulted in further significant increases in calcium deposition. Ca5 CaSR knockdown cells exhibited 70% calcification (95%CI 62–78), increased from 49% (95%CI 38–59) in Ca5 controls (p = 0.002), whereas both Gd CaSR knockdown (5.8, 95%CI 4.1–7.4 versus 2.7, 95%CI 1.7–3.8, p = 0.003) and Gd+Ca2 CaSR knockdown (5.0, 95%CI 3.0–6.9 versus 3.3, 95%CI 2.4–4.1, p = 0.046) HAoSMC also demonstrated significant but lesser increases in calcium deposition (Fig 2A and 2B).

Bottom Line: Vascular calcification (VC) is common in chronic kidney disease (CKD) and contributes to cardiovascular mortality.High extracellular calcium reduced CaSR expression and promoted osteochondrogenic transformation and calcium deposition.In arterial explants from CKD patients (n = 11) and controls (n = 9), exposure to R568 did not significantly alter calcium deposition, osteochondrogenic markers or total artery calcium content. physiological mechanical strain is important for arterial homeostasis and may protect arteries from VC.

View Article: PubMed Central - PubMed

Affiliation: The Clinical Sciences Research Laboratory, Warwick Medical School, University of Warwick, Coventry, United Kingdom.

ABSTRACT

Unlabelled: Vascular calcification (VC) is common in chronic kidney disease (CKD) and contributes to cardiovascular mortality. The calcium-sensing receptor (CaSR) is present in human artery, senses extracellular calcium and may directly modulate VC.

Objective: to investigate the association between arterial cyclic strain, CaSR expression and VC.

Methods and results: human aortic smooth muscle cells (HAoSMC) were cultured under static or strained conditions, with exposure to CaSR agonists, the calcimimetic R568, and after CaSR silencing and over-expression. High extracellular calcium reduced CaSR expression and promoted osteochondrogenic transformation and calcium deposition. This was partially prevented by cyclic strain and exposure to R568. CaSR silencing enhanced calcification and osteochondrogenic transformation, whereas CaSR over-expression attenuated this procalcific response, demonstrating a central role for the CaSR in the response to cyclic strain and regulation of VC. In arterial explants from CKD patients (n = 11) and controls (n = 9), exposure to R568 did not significantly alter calcium deposition, osteochondrogenic markers or total artery calcium content.

Conclusions: physiological mechanical strain is important for arterial homeostasis and may protect arteries from VC. The beneficial effects of cyclic strain may be mediated via the CaSR.

No MeSH data available.


Related in: MedlinePlus