scholarly journals Critical Involvement of Calcium-Dependent Cytosolic Phospholipase A2α in Aortic Valve Interstitial Cell Calcification

2020 ◽  
Vol 21 (17) ◽  
pp. 6398
Author(s):  
Antonella Bonetti ◽  
Lorenzo Allegri ◽  
Federica Baldan ◽  
Magali Contin ◽  
Claudio Battistella ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Interstitial Cell ◽  
Attractive Potential ◽  
Dystrophic Calcification ◽  
Calcium Dependent ◽  
Enzyme Content ◽  
Cytosolic Phospholipase ◽  
Cytosolic Phospholipase A2α ◽  
Novel Therapeutic Strategies

The involvement of calcium-dependent cytosolic phospholipase A2α (cPLA2α) in aortic valve calcification is not exhaustively elucidated. Here, cPLA2α expression in aortic valve interstitial cell (AVIC) pro-calcific cultures simulating either metastatic or dystrophic calcification was estimated by qPCR, Western blotting, and counting of cPLA2α-immunoreactive cells, with parallel ultrastructural examination of AVIC calcific degeneration. These evaluations also involved pro-calcific AVIC cultures treated with cPLA2α inhibitor dexamethasone. cPLA2α over-expression resulted for both types of pro-calcific AVIC cultures. Compared to controls, enzyme content was found to increase by up to 300% and 186% in metastatic and dystrophic calcification-like cultures, respectively. Increases in mRNA amounts were also observed, although they were not as striking as those in enzyme content. Moreover, cPLA2α increases were time-dependent and strictly associated with mineralization progression. Conversely, drastically lower levels of enzyme content resulted for the pro-calcific AVIC cultures supplemented with dexamethasone. In particular, cPLA2α amounts were found to decrease by almost 88% and 48% in metastatic and dystrophic calcification-like cultures, respectively, with mRNA amounts showing a similar trend. Interestingly, these drastic decreases in cPLA2α amounts were paralleled by drastic decreases in mineralization degrees, as revealed ultrastructurally. In conclusion, cPLA2α may be regarded as a crucial co-factor contributing to AVIC mineralization in vitro, thus being an attractive potential target for designing novel therapeutic strategies aimed to counteract onset or progression of calcific aortic valve diseases.

scholarly journals Zymosan-induced glycerylprostaglandin and prostaglandin synthesis in resident peritoneal macrophages: roles of cyclo-oxygenase-1 and -2

2006 ◽  
Vol 399 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Carol A. Rouzer ◽  
Susanne Tranguch ◽  
Haibin Wang ◽  
Hao Zhang ◽  
Sudhansu K. Dey ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Peritoneal Macrophages ◽  
Prostaglandin Synthesis ◽  
Wild Type ◽  
Cytosolic Phospholipase ◽  
Cytosolic Phospholipase A2α ◽  
Cox 2 ◽  
Cox 1 ◽  
Exogenous Substrates

COX [cyclo-oxygenase; PG (prostaglandin) G/H synthase] oxygenates AA (arachidonic acid) and 2-AG (2-arachidonylglycerol) to endoperoxides that are converted into PGs and PG-Gs (glycerylprostaglandins) respectively. In vitro, 2-AG is a selective substrate for COX-2, but in zymosan-stimulated peritoneal macrophages, PG-G synthesis is not sensitive to selective COX-2 inhibition. This suggests that COX-1 oxygenates 2-AG, so studies were carried out to identify enzymes involved in zymosan-dependent PG-G and PG synthesis. When macrophages from COX-1−/− or COX-2−/− mice were treated with zymosan, 20–25% and 10–15% of the PG and PG-G synthesis observed in wild-type cells respectively was COX-2 dependent. When exogenous AA and 2-AG were supplied to COX-2−/− macrophages, PG and PG-G synthesis was reduced as compared with wild-type cells. In contrast, when exogenous substrates were provided to COX-1−/− macrophages, PG-G but not PG synthesis was reduced. Product synthesis also was evaluated in macrophages from cPLA2α (cytosolic phospholipase A2α)−/− mice, in which zymosan-induced PG synthesis was markedly reduced, and PG-G synthesis was increased approx. 2-fold. These studies confirm that peritoneal macrophages synthesize PG-Gs in response to zymosan, but that this process is primarily COX-1-dependent, as is the synthesis of PGs. They also indicate that the 2-AG and AA used for PG-G and PG synthesis respectively are derived from independent pathways.

Benzenesulfonamide indole inhibitors of cytosolic phospholipase A2α: Optimization of in vitro potency and rat pharmacokinetics for oral efficacy

2008 ◽  
Vol 16 (3) ◽  
pp. 1345-1358 ◽  
Author(s):  
Katherine L. Lee ◽  
Mark L. Behnke ◽  
Megan A. Foley ◽  
Lihren Chen ◽  
Weiheng Wang ◽  
...  
Keyword(s):  
Cytosolic Phospholipase ◽  
Cytosolic Phospholipase A2α

scholarly journals Asporin Reduces Adult Aortic Valve Interstitial Cell Mineralization Induced by Osteogenic Media and Wnt Signaling Manipulation In Vitro

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Anisha Polley ◽  
Riffat Khanam ◽  
Arunima Sengupta ◽  
Santanu Chakraborty
Keyword(s):  
Aortic Valve ◽  
Aortic Valve Disease ◽  
Interstitial Cell ◽  
Valve Disease ◽  
Periodontal Ligament Cells ◽  
Calcific Aortic Valve Disease ◽  
Disease Manifestation ◽  
Regulatory Pathways ◽  
Replacement Surgery

Worldwide, calcific aortic valve disease is one of the leading causes of morbidity and mortality among patients with cardiac abnormalities. Aortic valve mineralization and calcification are the key events of adult calcific aortic valve disease manifestation and functional insufficiency. Due to heavy mineralization and calcification, adult aortic valvular cusps show disorganized and dispersed stratification concomitant with deposition of calcific nodules with severely compromised adult valve function. Interestingly, shared gene regulatory pathways are identified between bone-forming cells and heart valve cells during development. Asporin, a small leucine-rich proteoglycan (43 kDa), acts to inhibit mineralization in periodontal ligament cells and is also detected in normal murine adult aortic valve leaflets with unknown function. Therefore, to understand the Asporin function in aortic cusp mineralization and calcification, adult avian aortic valvular interstitial cell culture system is established and osteogenesis has been induced in these cells successfully. Upon induction of osteogenesis, reduced expression of Asporin mRNA and increased expression of bone and osteogenesis markers are detected compared to cells maintained without osteogenic induction. Importantly, treatment with human recombinant Asporin protein reduces the mineralization level in osteogenic media-induced aortic valvular interstitial cells with the concomitant decreased level of Wnt/β-catenin signaling. Overall, all these data are highly indicative that Asporin might be a novel biomolecular target to treat patients of calcific aortic valve disease over current cusp replacement surgery.

scholarly journals Inhibition of Cytosolic Phospholipase A2α Induces Apoptosis in Multiple Myeloma Cells

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7447
Author(s):  
Nur Mahammad ◽  
Felicity J. Ashcroft ◽  
Astrid J. Feuerherm ◽  
Samah Elsaadi ◽  
Esten N. Vandsemb ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Lines ◽  
Cancer Cell ◽  
Plasma Cells ◽  
Cancer Cell Lines ◽  
Myeloma Cells ◽  
Cytosolic Phospholipase ◽  
Hematological Cancers ◽  
Cytosolic Phospholipase A2α

Cytosolic phospholipase A2α (cPLA2α) is the rate-limiting enzyme in releasing arachidonic acid and biosynthesis of its derivative eicosanoids. Thus, the catalytic activity of cPLA2α plays an important role in cellular metabolism in healthy as well as cancer cells. There is mounting evidence suggesting that cPLA2α is an interesting target for cancer treatment; however, it is unclear which cancers are most relevant for further investigation. Here we report the relative expression of cPLA2α in a variety of cancers and cancer cell lines using publicly available datasets. The profiling of a panel of cancer cell lines representing different tissue origins suggests that hematological malignancies are particularly sensitive to the growth inhibitory effect of cPLA2α inhibition. Several hematological cancers and cancer cell lines overexpressed cPLA2α, including multiple myeloma. Multiple myeloma is an incurable hematological cancer of plasma cells in the bone marrow with an emerging requirement of therapeutic approaches. We show here that two cPLA2α inhibitors AVX420 and AVX002, significantly and dose-dependently reduced the viability of multiple myeloma cells and induced apoptosis in vitro. Our findings implicate cPLA2α activity in the survival of multiple myeloma cells and support further studies into cPLA2α as a potential target for treating hematological cancers, including multiple myeloma.

scholarly journals Calpain activity in patients with thrombotic thrombocytopenic purpura is associated with platelet microparticles

Blood ◽  
1992 ◽  
Vol 80 (9) ◽  
pp. 2246-2251 ◽  
Author(s):  
JG Kelton ◽  
TE Warkentin ◽  
CP Hayward ◽  
WG Murphy ◽  
JC Moore
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Membrane Association ◽  
Membrane Glycoproteins ◽  
Calpain Activity ◽  
Thrombocytopenic Purpura ◽  
Calcium Dependent ◽  
Active Protease ◽  
Triton X ◽  
Platelet Microparticles

Abstract Thrombotic thrombocytopenic purpura (TTP) is characterized by thrombocytopenia and disseminated platelet thrombi throughout the microvasculature. Studies by our group have demonstrated calcium- dependent proteolytic activity (calpain) that is no longer detectable in the serum of patients with acute TTP after their recovery. The purpose of this study was to investigate if the protease activity of TTP was detectable in plasma and, therefore, not an in vitro phenomenon secondary to the formation of serum. Additionally, we looked for evidence of membrane association of the active protease in the patients' samples, which would explain the persistence of its activity in the presence of plasma inhibitors. Acute TTP samples, both serum and plasma, were collected from 10 patients with TTP. Calpain was measured using bioassays for enzyme activity and also by detection of the protein using immunoblotting with an anticalpain monoclonal antibody (MoAb). In all instances, calpain could be detected both functionally and antigenically in the acute TTP sera and plasma. No calpain activity could be detected in any of the controls, although antigenic calpain was detectable in one sample from a patient who had undergone cardiopulmonary bypass surgery. To investigate whether the calpain was associated with microparticles in the plasma, the TTP plasma samples were ultrafiltered and ultracentrifuged. Activity was not lost by passage across a 0.2-micron filter but was detectable only in the pellet following ultracentrifugation. Membrane association of the calpain in the microparticles also was demonstrated using solubilization with Triton X-100. Immunoprecipitation studies demonstrated that the calpain activity could be removed by MoAbs against platelet membrane glycoproteins (IX and IIb/IIa) but not by a MoAb against red blood cell membrane glycophorin. These studies indicate that active calpain is associated with platelet microparticles in plasma from patients with TTP.

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