scholarly journals SAT-LB124 Phosphatidylcholine Transfer Protein Interacts With PPARδ to Modulate Activity

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Samuel Adam Druzak ◽  
Suzanne Mays ◽  
Eric Ortlund
Keyword(s):  
Cardiovascular Complications ◽  
Great Promise ◽  
Dependent Manner ◽  
Membrane Composition ◽  
Inhibitory Interaction ◽  
Littermate Control ◽  
Fatty Acid Binding ◽  
Transfer Protein ◽  
Phosphatidylcholine Transfer Protein

Abstract Obesity is one of the largest public health crises in the USA. Obesity can be lethal due to the development of cardiovascular complications such as, hypertension, heart attack, and stroke. Recently, peroxisome proliferator-activated receptor δ (PPARδ), the least-characterized member of the PPAR family of nuclear receptors (NRs), has shown great promise in treating obesity and associated cardiovascular complications. Recent reports have shown that PPARδ activation is tuned, in part, through an interaction with fatty acid binding protein 5 (FABP5) in a polyunsaturated Fatty acids (PUFAs) dependent manner. This enhancement is thought to occur due to ligand transfer, however, FABP5 only binds a subset of reported PPARδ ligands. To find other candidate lipid transport proteins (LTPs), we performed a protein complementation assay (PCA) between LTPs and NRs. We uncovered a novel interaction between PPARδ and phosphatidylcholine transfer protein (PC-TP), sensitive to cellular nutrient levels. Preliminary data show that this interaction opposes canonical PPARδ signaling, leading to a decrease in PPARδ transactivation in cells and isolated mice livers. This led me to hypothesize that PC-TP senses nutrient status through membrane composition. Specific PC molecular species drive PC-TP translocation to inhibit PPARδ transactivation of genes. Utilizing our novel PCA assay I have shown that the interaction is modulated in part by cellular levels of methionine and choline, as cells cultured in media depleted of methionine and choline (MCD) show a decreased in the interaction. Using the same assay, I have shown a requirement of full length PPARδ for the interaction with PC-TP. This analysis will be complimented by mutagenesis and chemical perturbations aimed to alter PC-TP and PPARδ function. Additionally, I have assayed the in vivo relevance of PC-TP interaction with PPARδ using livers harvested from PCTP-/- and littermate control mice fed a variety of diets. Preliminary RNA-seq characterization, show interesting alterations in gene expression that suggest more complex regulation between PC-TP and PPARδ in vivo. MCD, which was shown to reduce the inhibitory interaction between PC-TP and PPARδ in vitro, seems to lead to an increased effect on PPARδ transactivation when PC-TP is depleted. Analysis comparing the effect of diet within each genotype shows a loss of differential PPARδ regulation for both CHEA and KEGG analysis when comparing WT to PCTP -/- mice supporting a role for PC-TP in differential PPARδ regulation caused by MCD diet. These studies will further the understanding of how lipid homeostasis is sensed and maintained through PPARδ by interactions with two separate LTPs.

Effects of polymethoxylated flavone metabolites on apoB100 secretion and MTP activity in Huh7.5 cells

2021 ◽  
Vol 18 ◽  
Author(s):  
Danielle R. Gonçalves ◽  
Thais B. Cesar ◽  
John A. Manthey ◽  
Paulo I. Costa
Keyword(s):  
Lipid Synthesis ◽  
Dependent Manner ◽  
Transfer Protein ◽  
Low Concentrations ◽  
Wide Range ◽  
Cell Assays ◽  
Polymethoxylated Flavones ◽  
High Concentrations

Background: Citrus polymethoxylated flavones (PMFs) reduce the synthesis of liver lipoproteins in animal and in vitro cell assays, but few studies have evaluated the direct effects of their metabolites on this highly regulated process. Objective: To investigate the effects of representative metabolites of PMF on the secretion of liver lipoproteins using the mammalian cell Huh7.5. Method: In this study, the influences of three PMFs and five previously isolated PMF metabolites on hepatic apoB-100 secretion and microsomal transfer protein (MTP) activity were evaluated. Tangeretin (TAN), nobiletin (NOB) and 3,5,6,7,8,3′,4′-heptamethoxyflavone (HMF), and their glucuronides (TAN-Gluc, NOB-Gluc and HMF-Gluc) and oxidatively demethylated metabolites (TAN-OH, NOB-OH, HMF-OH) were incubated with Huh7.5 cells to measure their inhibitory effects on lipid synthesis. Results: The results showed that TAN, HMF and TAN-OH reduced the secretion of apoB-100 in a dose-dependent manner, while NOB and the other tested metabolites showed no inhibition. MTP activity in the Huh7.5 cells was significantly reduced in the presence of low concentrations of TAN, and in high concentrations of NOB-OH. This study also showed that PMFs and PMF metabolites produced a wide range of effects on apoB-100 secretion and MTP activity. Conclusion: The results suggest that while PMFs and their metabolites control dyslipidemia in vivo, the inhibition of MTP activity cannot be the only pathway influenced by these compounds.

Dose-dependent modulation of the T cell proteome by ascorbic acid

2007 ◽  
Vol 97 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Melissa M. Grant ◽  
Nalini Mistry ◽  
Joseph Lunec ◽  
Helen R. Griffiths
Keyword(s):  
Ascorbic Acid ◽  
T Cell ◽  
Dependent Manner ◽  
Transfer Protein ◽  
Phosphatidylinositol Transfer ◽  
Cell Proteome ◽  
Dose Dependent ◽  
H Protein ◽  
Dimensional Electrophoresis

To investigate the hypothesis that the micronutrient ascorbic acid can modulate the functional genome, T cells (CCRF-HSB2) were treated with ascorbic acid (up to 150 μm) for up to 24 h. Protein expression changes were assessed by two-dimensional electrophoresis. Forty-one protein spots which showed greater than two-fold expression changes were subject to identification by matrix-assisted laser desorption ionisation time of flight MS. The confirmed protein identifications were clustered into five groups; proteins were associated with signalling, carbohydrate metabolism, apoptosis, transcription and immune function. The increased expression of phosphatidylinositol transfer protein (promotes intracellular signalling) within 5 min of ascorbic acid treatment was confirmed by Western blotting. Together, these observations suggest that ascorbic acid modulates the T cell proteome in a time- and dose-dependent manner and identify molecular targets for study following antioxidant supplementation in vivo.

Synergic Effects of Proteasome Inhibitor PS-341 and Tyrosine Kinase Inhibitor STI571 on Chronic Myeloid Leukemia Cells and BCR-ABL Oncoprotein In Vitro and In Vivo.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4771-4771
Author(s):  
Guangbiao Zhou ◽  
Zheng Hu ◽  
Dapeng Liu ◽  
Fuqun Wu ◽  
Jiang Zhu ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Tumor Growth ◽  
Proteasome Inhibitor ◽  
Myeloid Leukemia ◽  
K562 Cells ◽  
Leukemic Cells ◽  
Great Promise ◽  
Dependent Manner

Abstract STI571/Gleevec/imatinib, a rationally-designed agent that occupies the ATP-binding site of BCR-ABL and stabilizes the protein in its closed, inactive conformation, has been a remarkable success for the treatment of chronic myeloid leukemia (CML). However, a significant proportion of patients chronically treated with STI571 develop resistance because of the acquisition of mutations in the kinase domain of BCR-ABL. Furthermore, the effects of STI571 on CML patients in accelerated phase or blastic crisis are unsatisfactory since many patients relapse after transient remission. Hence, additional drugs or STI571-based combination regimens are desired to circumvent resistance and to improve response rates. Here we reported that PS-341, a proteasome inhibitor which offers great promise to patients with multiple myeloma (MM), significantly enhanced the antileukemia activity of STI571 in vitro and in vivo. We found a synergy exists between low concentrations of PS-341 (5–10 nM) and STI571 (0.1–0.2 μM) in inhibition of cell growth and induction of apoptosis in K562 cell line and CD34+ leukemic cells isolated from CML patients. In K562 cells, combined use of PS-341 and STI571 accelerated activation of caspase-3, 9, and facilitated cleavage of poly-(ADP-ribose) polymerase (PARP) as compared to those in cells treated with PS-341 or STI571 alone. Moreover, PS-341/STI571 combination resulted in potentiated degradation of BCR-ABL and downregulation of phosphorylated BCR-ABL as compared to those in mono treatment. In nude mice inoculated subcutaneously with K562 cells, treatment with PS-341 (injected intraperitoneally, ip) alone (at doses of 0.05, 0.5, 1 mg/kg/d, twice a week for 4 weeks, respectively) decreased tumor growth in a dose-dependent manner. STI571 (ip) at 10 mg/kg/d also inhibited tumor growth. Intriguingly, combinatory administration of low dose PS-341 (0.05 mg/kg/d, twice a week for 4 weeks) and STI571 (10 mg/kg/d) yielded a much more profound inhibition of tumor growth and even clearance of leukemic cells in mice compared to either monotherapy. Taken together, these results demonstrate synergic effects of PS-341 and STI571, and provide the rationale to evaluate PS-341/STI571 combination in treating CML aiming to further improve clinical outcome of patients.

A20 inhibition of STAT1 expression in myeloid cells: a novel endogenous regulatory mechanism preventing development of enthesitis

2016 ◽  
Vol 76 (3) ◽  
pp. 585-592 ◽  
Author(s):  
Katelijne De Wilde ◽  
Arne Martens ◽  
Stijn Lambrecht ◽  
Peggy Jacques ◽  
Michael B Drennan ◽  
...  
Keyword(s):  
Gene Transcription ◽  
Myeloid Cells ◽  
Janus Kinase ◽  
Pcr Analysis ◽  
Placebo Control ◽  
Dependent Manner ◽  
Nucleotide Polymorphisms ◽  
Littermate Control ◽  
Endogenous Regulator

ObjectivesA20 is an important endogenous regulator of inflammation. Single nucleotide polymorphisms in A20 have been associated with various immune-mediated inflammatory diseases, and cell-specific deletion of A20 results in diverse inflammatory phenotypes. Our goal was to delineate the underlying mechanisms of joint inflammation in myeloid-specific A20-deficient mice (A20myelKO mice).MethodsInflammation in A20myelKO mice was assessed in a time-dependent manner. Western blot analysis and quantitative PCR analysis were performed on bone marrow-derived macrophages from A20myelKO and littermate control mice to study the effect of A20 on STAT1/STAT3 expression and STAT1/STAT3-dependent gene transcription in myeloid cells. The in vivo role of Janus kinase-Signal Transducer and Activator of Transcription (JAK-STAT) signalling in the development of enthesitis in A20myelKO mice was assessed following administration of a JAK inhibitor versus placebo control.ResultsEnthesitis was found to be an early inflammatory lesion in A20myelKO mice. A20 negatively modulated STAT1-dependent, but generally not STAT3-dependent gene transcription in myeloid cells by suppressing STAT1 but not STAT3 expression, both in unstimulated conditions and after interferon-γ or interleukin-6 stimulation. The increase in STAT1 gene transcription in the absence of A20 was shown to be JAK-STAT-dependent. Moreover, JAK inhibition in vivo resulted in significant reduction of enthesitis, both clinically and histopathologically.ConclusionsOur data reveal an important and novel interplay between myeloid cells and tissue resident cells at entheseal sites that is regulated by A20. In the absence of A20, STAT1 but not STAT3 expression is enhanced leading to STAT1-dependent inflammation. Therefore, A20 acts as a novel endogenous regulator of STAT1 that prevents onset of enthesitis.

Phosphatidylinositol-transfer protein and its homologues in yeast

2006 ◽  
Vol 34 (3) ◽  
pp. 377-380 ◽  
Author(s):  
P. Griac ◽  
R. Holic ◽  
D. Tahotna
Keyword(s):  
Membrane Trafficking ◽  
Diverse Group ◽  
Secretory Function ◽  
Lipid Transfer ◽  
Lipid Transfer Proteins ◽  
Transfer Protein ◽  
Phosphatidylinositol Transfer ◽  
Phosphatidylcholine Transfer Protein

Yeast Sec14p acts as a phosphatidylinositol/phosphatidylcholine-transfer protein in vitro. In vivo, it is essential in promoting Golgi secretory function. Products of five genes named SFH1–SFH5 (Sec Fourteen Homologues 1–5) exhibit significant sequence homology to Sec14p and together they form the Sec14p family of lipid-transfer proteins. It is a diverse group of proteins with distinct subcellular localizations and varied physiological functions related to lipid metabolism and membrane trafficking.

Targeted invalidation of SR-B1 in macrophages reduces macrophage apoptosis and accelerates atherosclerosis

2019 ◽  
Vol 116 (3) ◽  
pp. 554-565 ◽  
Author(s):  
Lauriane Galle-Treger ◽  
Martine Moreau ◽  
Raphaëlle Ballaire ◽  
Lucie Poupel ◽  
Thomas Huby ◽  
...  
Keyword(s):  
Dependent Manner ◽  
Aortic Atherosclerosis ◽  
Peripheral Tissues ◽  
Transfer Protein ◽  
Atherosclerotic Lesions ◽  
Macrophage Apoptosis ◽  
Induced Apoptosis ◽  
Apoptosis Inhibitor ◽  
Specific Contribution

Abstract Aims SR-B1 is a cholesterol transporter that exerts anti-atherogenic properties in liver and peripheral tissues in mice. Bone marrow (BM) transfer studies suggested an atheroprotective role in cells of haematopoietic origin. Here, we addressed the specific contribution of SR-B1 in the monocyte/macrophage. Methods and results We generated mice deficient for SR-B1 in monocytes/macrophages (Lysm-Cre × SR-B1f/f) and transplanted their BM into Ldlr−/− mice. Fed a cholesterol-rich diet, these mice displayed accelerated aortic atherosclerosis characterized by larger macrophage-rich areas and decreased macrophage apoptosis compared with SR-B1f/f transplanted controls. These findings were reproduced in BM transfer studies using another atherogenic mouse recipient (SR-B1 KOliver × Cholesteryl Ester Transfer Protein). Haematopoietic reconstitution with SR-B1−/− BM conducted in parallel generated similar results to those obtained with Lysm-Cre × SR-B1f/f BM; thus suggesting that among haematopoietic-derived cells, SR-B1 exerts its atheroprotective role primarily in monocytes/macrophages. Consistent with our in vivo data, free cholesterol (FC)-induced apoptosis of macrophages was diminished in the absence of SR-B1. This effect could not be attributed to differential cellular cholesterol loading. However, we observed that expression of apoptosis inhibitor of macrophage (AIM) was induced in SR-B1-deficient macrophages, and notably upon FC-loading. Furthermore, we demonstrated that macrophages were protected from FC-induced apoptosis by AIM. Finally, AIM protein was found more present within the macrophage-rich area of the atherosclerotic lesions of SR-B1-deficient macrophages than controls. Conclusion Our findings suggest that macrophage SR-B1 plays a role in plaque growth by controlling macrophage apoptosis in an AIM-dependent manner.

scholarly journals Taurine Attenuates the Hypotaurine-Induced Progression of CRC via ERK/RSK Signaling

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaodan Hou ◽  
Junwei Hu ◽  
Xinyu Zhao ◽  
Qing Wei ◽  
Rongping Zhao ◽  
...  
Keyword(s):  
Cellular Proliferation ◽  
Epithelial Mesenchymal Transition ◽  
Malignant Tumors ◽  
Gas Chromatography Mass Spectrometry ◽  
Great Promise ◽  
Dependent Manner ◽  
Mesenchymal Transition ◽  
Induced Apoptosis

Colorectal cancer (CRC) is one of the most common malignant tumors, and previous metabolomics work has demonstrated great promise in identifying specific small molecules of tumor phenotype. In the present study, we analyzed the metabolites of resected tissues through gas chromatography-mass spectrometry (GC-MS), and found that the concentration of taurine in CRC tissues diminished whereas the concentration of hypotaurine increased. The results in vitro demonstrated that taurine significantly suppressed cellular proliferation, metastasis, and colony formation whereas it induced apoptosis in CRC cells. Furthermore, taurine regulated the expression levels of epithelial mesenchymal transition (EMT)-associated genes in a dose-dependent manner. Taurine also alleviated hypotaurine-induced CRC progression, which was linked to the inhibition of the ERK/RSK-signaling pathway and diminution in intracellular hypotaurine. Taurine additionally attenuated hypotaurine-induced tumor growth and metastasis in vivo. Patients with CRC exhibited lower levels of serum taurine, suggesting that taurine might be a promising biomarker reflecting a poor prognosis in CRC. Collectively, our results demonstrated that taurine-attenuated, hypotaurine-induced CRC progression provides a potential target for CRC therapy.

Effects of NO-Donors on Thrombus Formation and Microcirculation in Cerebral Vessels of the Rat

1996 ◽  
Vol 76 (01) ◽  
pp. 111-117 ◽  
Author(s):  
Yasuto Sasaki ◽  
Junji Seki ◽  
John C Giddings ◽  
Junichiro Yamamoto
Keyword(s):  
Blood Flow ◽  
Thrombus Formation ◽  
Dependent Manner ◽  
Red Cell ◽  
Cell Velocity ◽  
Red Cell Velocity ◽  
The Mean ◽  
Wall Shear ◽  
Dose Dependent

SummarySodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), are known to liberate nitric oxide (NO). In this study the effects of SNP and SIN-1 on thrombus formation in rat cerebral arterioles and venules in vivo were assessed using a helium-neon (He-Ne) laser. SNP infused at doses from 10 Μg/kg/h significantly inhibited thrombus formation in a dose dependent manner. This inhibition of thrombus formation was suppressed by methylene blue. SIN-1 at a dose of 100 Μg/kg/h also demonstrated a significant antithrombotic effect. Moreover, treatment with SNP increased vessel diameter in a dose dependent manner and enhanced the mean red cell velocity measured with a fiber-optic laser-Doppler anemometer microscope (FLDAM). Blood flow, calculated from the mean red cell velocity and vessel diameters was increased significantly during infusion. In contrast, mean wall shear rates in the arterioles and venules were not changed by SNP infusion. The results indicated that SNP and SIN-1 possessed potent antithrombotic activities, whilst SNP increased cerebral blood flow without changing wall shear rate. The findings suggest that the NO released by SNP and SIN-1 may be beneficial for the treatment and protection of cerebral infarction

The Effect of Active Site-inhibited Factor VIIa on Tissue Factor-initiated Coagulation Using Platelets before and after Aspirin Administration

1997 ◽  
Vol 78 (04) ◽  
pp. 1202-1208 ◽  
Author(s):  
Marianne Kjalke ◽  
Julie A Oliver ◽  
Dougald M Monroe ◽  
Maureane Hoffman ◽  
Mirella Ezban ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Active Site ◽  
Large Scale ◽  
Thrombin Generation ◽  
Factor Viia ◽  
Dependent Manner ◽  
Antithrombotic Agent ◽  
Before And After ◽  
Ic50 Values

SummaryActive site-inactivated factor VIIa has potential as an antithrombotic agent. The effects of D-Phe-L-Phe-L-Arg-chloromethyl ketone-treated factor VIla (FFR-FVIIa) were evaluated in a cell-based system mimicking in vivo initiation of coagulation. FFR-FVIIa inhibited platelet activation (as measured by expression of P-selectin) and subsequent large-scale thrombin generation in a dose-dependent manner with IC50 values of 1.4 ± 0.8 nM (n = 8) and 0.9 ± 0.7 nM (n = 7), respectively. Kd for factor VIIa binding to monocytes ki for FFR-FVIIa competing with factor VIIa were similar (11.4 ± 0.8 pM and 10.6 ± 1.1 pM, respectively), showing that FFR-FVIIa binds to tissue factor in the tenase complex with the same affinity as factor VIIa. Using platelets from volunteers before and after ingestion of aspirin (1.3 g), there were no significant differences in the IC50 values of FFR-FVIIa [after aspirin ingestion, the IC50 values were 1.7 ± 0.9 nM (n = 8) for P-selectin expression, p = 0.37, and 1.4 ± 1.3 nM (n = 7) for thrombin generation, p = 0.38]. This shows that aspirin treatment of platelets does not influence the inhibition of tissue factor-initiated coagulation by FFR-FVIIa, probably because thrombin activation of platelets is not entirely dependent upon expression of thromboxane A2.

Chickpea (Cicer arietinum L.) Lectin Exhibit Inhibition of ACE-I, α-amylase and α-glucosidase Activity

2019 ◽  
Vol 26 (7) ◽  
pp. 494-501 ◽  
Author(s):  
Sameer Suresh Bhagyawant ◽  
Dakshita Tanaji Narvekar ◽  
Neha Gupta ◽  
Amita Bhadkaria ◽  
Ajay Kumar Gautam ◽  
...  
Keyword(s):  
Biological Effects ◽  
Exchange Chromatography ◽  
Health Concern ◽  
Carbohydrate Binding ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ic50 Values ◽  
Chickpea Lectin

Background: Diabetes and hypertension are the major health concern and alleged to be of epidemic proportions. This has made it a numero uno subject at various levels of investigation. Glucosidase inhibitor provides the reasonable option in treatment of Diabetes Mellitus (DM) as it specifically targets post prandial hyperglycemia. The Angiotensin Converting Enzyme (ACE) plays an important role in hypertension. Therefore, inhibition of ACE in treatment of elevated blood pressure attracts special interest of the scientific community. Chickpea is a food legume and seeds contain carbohydrate binding protein- a lectin. Some of the biological properties of this lectin hitherto been elucidated. Methods: Purified by ion exchange chromatography, chickpea lectin was tested for its in vitro antioxidant, ACE-I inhibitory and anti-diabetic characteristic. Results: Lectin shows a characteristic improvement over the synthetic drugs like acarbose (oral anti-diabetic drug) and captopril (standard antihypertensive drug) when, their IC50 values are compared. Lectin significantly inhibited α-glucosidase and α-amylase in a concentration dependent manner with IC50 values of 85.41 ± 1.21 ҝg/ml and 65.05 ± 1.2 µg/ml compared to acarbose having IC50 70.20 ± 0.47 value of µg/ml and 50.52 ± 1.01 µg/ml respectively. β-Carotene bleaching assay showed antioxidant activity of lectin (72.3%) to be as active as Butylated Hydroxylanisole (BHA). In addition, lectin demonstrated inhibition against ACE-I with IC50 value of 57.43 ± 1.20 µg/ml compared to captopril. Conclusion: Lectin demonstrated its antioxidant character, ACE-I inhibition and significantly inhibitory for α-glucosidase and α-amylase seems to qualify as an anti-hyperglycemic therapeutic molecule. The biological effects of chickpea lectin display potential for reducing the parameters of medically debilitating conditions. These characteristics however needs to be established under in vivo systems too viz. animals through to humans.

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