scholarly journals Classical Transient Receptor Potential 1 and 6 Contribute to Hypoxic Pulmonary Hypertension Through Differential Regulation of Pulmonary Vascular Functions

Hypertension ◽  
2014 ◽  
Vol 63 (1) ◽  
pp. 173-180 ◽  
Author(s):  
Yang Xia ◽  
Xiao-Ru Yang ◽  
Zhenzhen Fu ◽  
Omkar Paudel ◽  
Joel Abramowitz ◽  
...  
2010 ◽  
Vol 299 (5) ◽  
pp. L621-L630 ◽  
Author(s):  
Gongyong Peng ◽  
Wenju Lu ◽  
Xiaoyan Li ◽  
Yuqin Chen ◽  
Nanshan Zhong ◽  
...  

Chronic hypoxia causes remodeling and alters contractile responses in both pulmonary arteries and pulmonary veins. Although pulmonary arteries have been studied extensively in these disorders, the mechanisms by which pulmonary veins respond to hypoxia and whether these responses contribute to chronic hypoxic pulmonary hypertension remain poorly understood. In pulmonary arterial smooth muscle, we have previously demonstrated that influx of Ca2+ through store-operated calcium channels (SOCC) thought to be composed of transient receptor potential (TRP) proteins is likely to play an important role in development of chronic hypoxic pulmonary hypertension. To determine whether this mechanism could also be operative in pulmonary venous smooth muscle, we measured intracellular Ca2+ concentration ([Ca2+]i) by fura-2 fluorescence microscopy in primary cultures of pulmonary venous smooth muscle cells (PVSMC) isolated from rat distal pulmonary veins. In cells perfused with Ca2+-free media containing cyclopiazonic acid (10 μM) and nifedipine (5 μM) to deplete sarcoplasmic reticulum Ca2+ stores and block voltage-dependent Ca2+ channels, restoration of extracellular Ca2+ (2.5 mM) caused marked increases in [Ca2+]i, whereas MnCl2 (200 μM) quenched fura-2 fluorescence, indicating store-operated Ca2+ entry (SOCE). SKF-96365 and NiCl2, antagonists of SOCC, blocked SOCE at concentrations that did not alter Ca2+ responses to 60 mM KCl. Of the seven known canonical TRP (TRPC1–7) and six vanilloid-related TRP channels (TRPV1–6), real-time PCR revealed mRNA expression of TRPC1 > TRPC6 > TRPC4 > TRPC2 ≈ TRPC5 > TRPC3, TRPV2 > TRPV4 > TRPV1 in distal PVSMC, and TRPC1 > TRPC6 > TRPC3 > TRPC4 ≈ TRPC5, TRPV2 ≈ TRPV4 > TRPV1 in rat distal pulmonary vein (PV) smooth muscle. Western blotting confirmed protein expression of TRPC1, TRPC6, TRPV2, and TRPV4 in both PVSMC and PV. Our results suggest that SOCE through Ca2+ channels composed of TRP proteins may contribute to Ca2+ signaling in rat distal PV smooth muscle.


2016 ◽  
Vol 311 (3) ◽  
pp. C482-C497 ◽  
Author(s):  
Jun Zhang ◽  
Wenju Lu ◽  
Yuqin Chen ◽  
Qian Jiang ◽  
Kai Yang ◽  
...  

The ubiquitin-proteasome system is considered to be the key regulator of protein degradation. Bortezomib (BTZ) is the first proteasome inhibitor approved by the US Food and Drug Administration for treatment of relapsed multiple myeloma and mantle cell lymphoma. Recently, BTZ treatment was reported to inhibit right ventricular hypertrophy and vascular remodeling in hypoxia-exposed and monocrotaline-injected rats. However, the underlying mechanisms remain poorly understood. We previously confirmed that hypoxia-elevated basal intracellular Ca2+ concentration ([Ca2+]i) and store-operated Ca2+ entry (SOCE) in pulmonary artery smooth muscle cells (PASMCs) are involved in pulmonary vascular remodeling. In this study we aim to determine whether BTZ attenuates the hypoxia-induced elevation of [Ca2+] in PASMCs and the signaling pathway involved in this mechanism. Our results showed that 1) in hypoxia- and monocrotaline-induced rat pulmonary hypertension (PH) models, BTZ markedly attenuated the development and progression of PH, 2) BTZ inhibited the hypoxia-induced increase in cell proliferation, basal [Ca2+]i, and SOCE in PASMCs, and 3) BTZ significantly normalized the hypoxia-upregulated expression of hypoxia-inducible factor-1α, bone morphogenetic protein 4, canonical transient receptor potential isoforms 1 and 6, and the hypoxia-downregulated expression of peroxisome proliferator-activated receptor-γ in rat distal pulmonary arteries and PASMCs. These results indicate that BTZ exerts its protective role in the development of PH potentially by inhibiting the canonical transient receptor potential-SOCE-[Ca2+]i signaling axis in PASMCs.


2012 ◽  
Vol 24 (1) ◽  
pp. 186
Author(s):  
T. H. Koo ◽  
E. B. Jeung

During pregnancy, the placenta represents the establishment of an intimate connection between mother and fetus that is specific to mammals. Calbindins [Calbindin-D9k (CaBP-9k) and -D28k (CaBP-28k)] are proteins possessing EF-hand motifs that have a high affinity for Ca2+ ions and play an important role in the regulation and buffering of Ca2+ in the various tissues. Many types of calcium channels, intracellular calcium binding proteins, Na+/Ca2+ exchangers (NCX) and transient receptor potential cation channels (TRPV) have been found in the placenta. In this study, the calcium channel in maternal-fetal Ca2+ transport was investigated using the phenotypes of wild-type, CaBP-9k, CaBP-28k and CaBP-9k/28k knockout (KO) mouse models. Expressions of calcium transport genes in 3 dissected sections of placenta (MP: maternal, CP: central, FP: fetal) were examined by real-time RT-PCR (RT-qPCR) and Western blot analysis at gestational Day 19 in these mice. The level of TRPV6 mRNA and protein was highest in the MP and CP of CaBP-28k KO mice and the FP of CaBP-9k KO mice compared with other sections of KO mice. The level of CaBP-9k was significantly induced in CaBP-28k KO mice in MP, CP and FP compared with in WT mice, which levels were elevated from maternal to fetal sections. The expression of CaBP-28k mRNA and protein was reduced in CaBP-9k KO mice compared with WT in the 3 sections of placenta. The expression of NCX1 mRNA and protein was higher in all KO mice than in WT in MP and NCX1 was highest in CaBP-28k KO mice in CP, but strong in CaBP-9k KO mice in FP compared with other strains. These results indicate that TRPV6 and NCX1 participate in transferring calcium ions between maternal and fetal compartments and alteration of CaBP-9k/28k is involved in the intracellular Ca2+ buffering system among WT and KO mice. These results taken together indicate that TRPV6 and CaBP-9k genes may play a role as a key element in controlling placental calcium transport during pregnancy.


2013 ◽  
Vol 188 (12) ◽  
pp. 1451-1459 ◽  
Author(s):  
Monika Malczyk ◽  
Christine Veith ◽  
Beate Fuchs ◽  
Katharina Hofmann ◽  
Ursula Storch ◽  
...  

2013 ◽  
Vol 305 (7) ◽  
pp. C704-C715 ◽  
Author(s):  
Yang Xia ◽  
Zhenzhen Fu ◽  
Jinxing Hu ◽  
Chun Huang ◽  
Omkar Paudel ◽  
...  

Transient receptor potential vanilloid 4 (TRPV4) is a mechanosensitive channel in pulmonary arterial smooth muscle cells (PASMCs). Its upregulation by chronic hypoxia is associated with enhanced myogenic tone, and genetic deletion of trpv4 suppresses the development of chronic hypoxic pulmonary hypertension (CHPH). Here we further examine the roles of TRPV4 in agonist-induced pulmonary vasoconstriction and in the enhanced vasoreactivity in CHPH. Initial evaluation of TRPV4-selective antagonists HC-067047 and RN-1734 in KCl-contracted pulmonary arteries (PAs) of trpv4−/−mice found that submicromolar HC-067047 was devoid of off-target effect on pulmonary vasoconstriction. Inhibition of TRPV4 with 0.5 μM HC-067047 significantly reduced the sensitivity of serotonin (5-HT)-induced contraction in wild-type (WT) PAs but had no effect on endothelin-1 or phenylephrine-activated response. Similar shift in the concentration-response curve of 5-HT was observed in trpv4−/−PAs, confirming specific TRPV4 contribution to 5-HT-induced vasoconstriction. 5-HT-induced Ca2+response was attenuated by HC-067047 in WT PASMCs but not in trpv4−/−PASMCs, suggesting TRPV4 is a major Ca2+pathway for 5-HT-induced Ca2+mobilization. Nifedipine also attenuated 5-HT-induced Ca2+response in WT PASMCs but did not cause further reduction in the presence of HC-067047, suggesting interdependence of TRPV4 and voltage-gated Ca2+channels in the 5-HT response. Chronic exposure (3–4 wk) of WT mice to 10% O2caused significant increase in 5-HT-induced maximal contraction, which was partially reversed by HC-067047. In concordance, the enhancement of 5-HT-induced contraction was significantly reduced in PAs of CH trpv4−/−mice and HC-067047 had no further effect on the 5-HT induced response. These results suggest unequivocally that TRPV4 contributes to 5-HT-dependent pharmaco-mechanical coupling and plays a major role in the enhanced pulmonary vasoreactivity to 5-HT in CHPH.


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