scholarly journals Olanzapine inhibits hepatic apolipoprotein A5 secretion inducing hypertriglyceridemia in schizophrenia patients and mice

2021 ◽  
Author(s):  
Xiansheng Huang ◽  
Yiqi Zhang ◽  
Wenqiang Zhu ◽  
Piaopiao Huang ◽  
Jingmei Xiao ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Plasma Triglyceride ◽  
High Dose ◽  
Mrna Levels ◽  
Apolipoprotein A5 ◽  
Protein Levels ◽  
Olanzapine Treatment ◽  
Primary Mouse

Olanzapine, an antipsychotic drug, was reported to induce hypertriglyceridemia, whereas the underlying mechanism remains incompletely understood. This study was to determine the role of apolipoprotein A5 (apoA5) in olanzapine-induced hypertriglyceridemia. In this study, 36 drug-naive and first-episode schizophrenic adult patients (aged 18-60 years) in a multi-center clinical trial (ClinicalTrials.gov NCT03451734) were enrolled. Before and after olanzapine treatment, plasma lipid and apoA5 levels were detected. Moreover, 21 female C57BL/6 J mice (8 weeks old) were divided into 3 groups (n = 7/each group): low-dose olanzapine (3 mg/kg/day), high-dose olanzapine (6 mg/kg/day) and control group. After 6 weeks, plasma glucose, lipids and apoA5 as well as hepatic apoA5 protein and mRNA expression in these animals were detected. In our study in vitro, primary mouse hepatocytes and HepG2 cells were treated with olanzapine of 25, 50, 100 μmol/L, respectively. After 24 hours, apoA5 protein and mRNA levels in hepatocytes were detected. Our study showed that olanzapine treatment significantly increased plasma triglyceride levels and decreased plasma apoA5 levels in these schizophrenic patients. A significant negative correlation was indicated between plasma triglyceride and apoA5 levels in these patients. Consistently, olanzapine dose-dependently increased plasma triglyceride levels and decreased plasma apoA5 levels in mice. Surprisingly, an elevation of hepatic apoA5 protein levels was detected in mice after olanzapine treatment, with no changes of APOA5 mRNA expression. Likewise, olanzapine increased apoA5 protein levels in hepatocytes in vitro, without changes of hepatocyte APOA5 mRNA. Therefore, our study provides the first evidence about the role of apoA5 in olanzapine-induced hypertriglyceridemia. Furthermore, plasma apoA5 reduction, resulting in hypertriglyceridemia, could be attributed to olanzapine-induced inhibition of hepatic apoA5 secretion.

scholarly journals Serotonin-Exacerbated DSS-Induced Colitis Is Associated with Increase in MMP-3 and MMP-9 Expression in the Mouse Colon

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Menglu Chen ◽  
Lei Gao ◽  
Pan Chen ◽  
Dandan Feng ◽  
Yalin Jiang ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Low Dose ◽  
Intestinal Inflammation ◽  
Human Neutrophils ◽  
High Dose ◽  
Mrna Levels ◽  
Protein Levels ◽  
Mouse Colon ◽  
Inflammatory Bowel

Background. 5-HT enhances dextran sulfate sodium- (DSS-) induced colitis and is involved in inflammatory bowel disease (IBD). Matrix metalloproteinases (MMPs) play roles in the process of intestinal inflammation.Aims. To examine whether 5-HT induces MMPs expression in mouse colon to enhance DSS-induced colitis.Materials and Methods. C57BL/6J (B6) mice were treated with either low-dose (1.0 mg/kg) or high-dose (2.0 mg/kg) 5-HT by enema, low-dose (1.0%) or high-dose (2.5%) DSS, or combined low-dose (1.0%) DSS and (1.0 mg/kg) 5-HT. Mouse colitis was analyzed. MMPs and tissue inhibitors of MMPs (TIMPs) mRNA were measured by real-time quantitative RT-PCR in mouse colon and in human Caco-2 cells and neutrophils. MMP-3 and MMP-9 protein levels were quantified from immunohistochemistry (IHC) images of mouse colons.Results. 5-HT exacerbated DSS-induced colitis, low-dose 5-HT induces both MMP-3 and MMP-9, and high-dose 5-HT only increased MMP-3 mRNA expression in mouse colon. Mouse colon MMP-3 and MMP-9 protein levels were also elevated by 5-HT treatment. The MMP-2, TIMP-1, and TIMP-2 mRNA levels were increased in the inflamed colon. 5-HT induced MMP-3 and MMP-9 mRNA expression in Caco-2 and human neutrophils, respectively, in vitro.Conclusion. 5-HT induced MMP-3 and MMP-9 expression in mouse colon; these elevated MMPs may contribute to DSS-induced colitis.

scholarly journals The Role of the FOXO1/β2-AR/p-NF-κB p65 Pathway in the Development of Endometrial Stromal Cells in Pregnant Mice under Restraint Stress

2021 ◽  
Vol 22 (3) ◽  
pp. 1478
Author(s):  
Jiayin Lu ◽  
Yaoxing Chen ◽  
Zixu Wang ◽  
Jing Cao ◽  
Yulan Dong
Keyword(s):  
Oxidative Stress ◽  
Stromal Cells ◽  
Restraint Stress ◽  
Target Genes ◽  
Mrna Levels ◽  
Endometrial Stromal Cells ◽  
Protein Levels ◽  
Pregnant Mice

Restraint stress causes various maternal diseases during pregnancy. β2-Adrenergic receptor (β2-AR) and Forkhead transcription factor class O 1 (FOXO1) are critical factors not only in stress, but also in reproduction. However, the role of FOXO1 in restraint stress, causing changes in the β2-AR pathway in pregnant mice, has been unclear. The aim of this research was to investigate the β2-AR pathway of restraint stress and its impact on the oxidative stress of the maternal uterus. In the study, maternal mice were treated with restraint stress by being restrained in a transparent and ventilated device before sacrifice on Pregnancy Day 5 (P5), Pregnancy Day 10 (P10), Pregnancy Day 15 (P15), and Pregnancy Day 20 (P20) as well as on Non-Pregnancy Day 5 (NP5). Restraint stress augmented blood corticosterone (CORT), norepinephrine (NE), and blood glucose levels, while oestradiol (E2) levels decreased. Moreover, restraint stress increased the mRNA levels of the FOXO family, β2-AR, and even the protein levels of FOXO1 and β2-AR in the uterus and ovaries. Furthermore, restraint stress increased uterine oxidative stress level. In vitro, the protein levels of FOXO1 were also obviously increased when β2-AR was activated in endometrial stromal cells (ESCs). In addition, phosphorylated-nuclear factor kappa-B p65 (p-NF-κB p65) and its target genes decreased significantly when FOXO1 was inhibited. Overall, it can be said that the β2-AR/FOXO1/p-NF-κB p65 pathway was activated when pregnant mice were under restraint stress. This study provides a scientific basis for the origin of psychological stress in pregnant women.

scholarly journals Absence of Thyroid Hormone Induced Delayed Dendritic Arborization in Mouse Primary Hippocampal Neurons Through Insufficient Expression of Brain-Derived Neurotrophic Factor

2021 ◽  
Vol 12 ◽  
Author(s):  
Hiroyuki Yajima ◽  
Izuki Amano ◽  
Sumiyasu Ishii ◽  
Tetsushi Sadakata ◽  
Wataru Miyazaki ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Neurotrophic Factor ◽  
Hippocampal Neurons ◽  
Brain Derived Neurotrophic Factor ◽  
Mrna Levels ◽  
Protein Levels ◽  
Primary Hippocampal Neurons ◽  
Developmental Impairment

Thyroid hormone (TH) plays important roles in the developing brain. TH deficiency in early life leads to severe developmental impairment in the hippocampus. However, the mechanisms of TH action in the developing hippocampus are still largely unknown. In this study, we generated 3,5,3’-tri-iodo-l-thyronine (T3)-free neuronal supplement, based on the composition of neuronal supplement 21 (NS21), to examine the effect of TH in the developing hippocampus using primary cultured neurons. Effects of TH on neurons were compared between cultures in this T3-free culture medium (-T3 group) and a medium in which T3 was added (+T3 group). Morphometric analysis and RT-qPCR were performed on 7, 10, and 14 days in vitro (DIV). On 10 DIV, a decreased dendrite arborization in -T3 group was observed. Such difference was not observed on 7 and 14 DIV. Brain-derived neurotrophic factor (Bdnf) mRNA levels also decreased significantly in -T3 group on 10 DIV. We then confirmed protein levels of phosphorylated neurotrophic tyrosine kinase type 2 (NTRK2, TRKB), which is a receptor for BDNF, on 10 DIV by immunocytochemistry and Western blot analysis. Phosphorylated NTRK2 levels significantly decreased in -T3 group compared to +T3 group on 10 DIV. Considering the role of BDNF on neurodevelopment, we examined its involvement by adding BDNF on 8 and 9 DIV. Addition of 10 ng/ml BDNF recovered the suppressed dendrite arborization induced by T3 deficiency on 10 DIV. We show that the lack of TH induces a developmental delay in primary hippocampal neurons, likely caused through a decreased Bdnf expression. Thus, BDNF may play a role in TH-regulated dendritogenesis.

245 EXPRESSION AND FUNCTIONAL ROLE OF CELL DIVISION CYCLE 42 IN MOUSE OOCYTES MATURATION AND PRE-IMPLANTATION DEVELOPMENT

2006 ◽  
Vol 18 (2) ◽  
pp. 230
Author(s):  
X.-S. Cui ◽  
X.-Y. Li ◽  
N.-H. Kim
Keyword(s):  
Protein Synthesis ◽  
Cell Division ◽  
Mrna Expression ◽  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Cell Division Cycle ◽  
Mrna Levels ◽  
Mouse Oocytes

Cell division cycle 42 (Cdc42), a member of the Rho family of small guanosine triphosphatase (GTPase) proteins, regulates multiple cell functions, including motility, proliferation, apoptosis, and cell morphology. In order to gain insight into the role of Cdc42 in embryo development, we first characterized mRNA and protein levels of Cdc42 in mouse oocytes and early embryogenesis. We then examined the possible role of the gene in oocyte maturation and pre-implantation development using RNA interference analysis. The relative abundance of Cdc42 transcripts were measured by real time RT-PCR. After normalization with histone H2a mRNA levels, the mRNA expression of Cdc42 was abundant in immature oocytes and reduced slightly in zygotes and 2- to 8-cell stage embryos. The expression levels were significantly increased during the morula and blastocyst stages. Indirect immunocytochemistry showed protein synthesis of Cdc42 in oocytes and embryos of all stages. Introducing small interference RNA (siRNA) of Cdc42 into germinal vesicle stage oocytes or zygotes specifically reduce both mRNA expression and protein synthesis of Cdc42 in metaphase II stage oocytes and early embryos developing in vitro. Meiotic maturation was significantly reduced following siRNA injection into germinal vesicle stage oocytes. It is evident that actin distribution in siRNA treated blastocysts is morphologically abnormal following injection of siRNA for Cdc42. Injection of siRNA into zygotes did not influence cleavage, but significantly decreased in vitro development to morulae and blastocysts. While housekeeping genes such as tissue plasminogen activator were not altered by siRNA, wiskott-aldrich syndrome protein family 1 (WASP1) mRNA was down-regulated in the morula. Interestingly, mRNA of WASP1, tubulin alpha 1 (Tuba1), and actin-related protein 2/3 complex subunit V (Arpc5) increased at the blastocyst stage following siRNA injection. These results suggest that Cdc42 plays an important role during oocyte maturation and early pre-implantation development, likely through linkage with several other genes. This work was funded by a grant from National Research Laboratory Program in Korea.

scholarly journals Renal miR-148b is associated with megalin down-regulation in IgA nephropathy

2018 ◽  
Vol 38 (6) ◽  
Author(s):  
Lu Wen ◽  
Zhanzheng Zhao ◽  
Jing Xiao ◽  
Zheng Wang ◽  
Xiangfei He ◽  
...  
Keyword(s):  
Proximal Tubule ◽  
Mrna Expression ◽  
Iga Nephropathy ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Mrna Levels ◽  
Immunofluorescence Labeling ◽  
Normal Controls

Megalin is essential for proximal tubule reabsorption of filtered proteins, hormones, and vitamins, and its dysfunction has been reported in IgA nephropathy (IgAN). miR-148b has been shown to regulate renal megalin expression in vitro and in animal models of kidney disease. We examined a potential role of miR-148b and other miRNAs in regulating megalin expression in IgAN by analyzing the association between megalin and miR-148b, miR-21, miR-146a, and miR-192 expression. Quantitative PCR (qPCR) analysis identified a marked increase in renal levels of several miRNAs, including miR-148b, miR-21, miR-146a, and a significant decrease in megalin mRNA levels in IgAN patients when compared with normal controls. By multiple linear regression analysis, however, only renal miR-148b was independently associated with megalin mRNA levels in IgAN. Proximal tubule megalin expression was further evaluated by immunofluorescence labeling of biopsies from the patients. The megalin expression was significantly lower in patients with highest levels of renal miR-148b compared with patients with lowest levels. To examine the direct effects of the miRNAs on megalin and other membrane proteins expression, proximal tubule LLC-PK1 cells were transfected with miR-148b, miR-21, miR-146a, or miR-192 mimics. Transfection with miR-148b mimic, but not the other three miRNA mimics inhibited endogenous megalin mRNA expression. No significant effect of any of the four miRNA mimics was observed on cubilin or aquaporin 1 (AQP1) mRNA expression. The findings suggest that miR-148b negatively regulates megalin expression in IgAN, which may affect renal uptake and metabolism of essential substances.

Role of the TNF pathway in the progression of diabetic nephropathy in KK-Ay mice

2014 ◽  
Vol 306 (11) ◽  
pp. F1335-F1347 ◽  
Author(s):  
Keisuke Omote ◽  
Tomohito Gohda ◽  
Maki Murakoshi ◽  
Yu Sasaki ◽  
Saiko Kazuno ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Early Stage ◽  
Mrna Levels ◽  
Monocyte Chemoattractant Protein 1 ◽  
Protein Levels ◽  
Tnf Α ◽  
Soluble Tnf Receptor

Chronic inflammation promotes the progression of diabetic nephropathy (DN). However, the role of TNF-α remains unclear. The objectives of the present study were to examine whether TNF-α inhibition with a soluble TNF receptor (TNFR)2 fusion protein, i.e., etanercept (ETN), improves the early stage of DN in the type 2 diabetic model of the KK-Ay mouse and to also investigate which TNF pathway, TNFR1 or TNFR2, is predominantly involved in the progression of this disease. ETN was injected intraperitoneally into mice for 8 wk. Renal damage was evaluated by immunohistochemistry, Western blot analysis, and/or real-time PCR. In vitro, mouse tubular proximal cells were stimulated by TNF-α and/or high glucose (HG) and treated with ETN. ETN dramatically improved not only albuminuria but also glycemic control. Renal mRNA and/or protein levels of TNFR2, but not TNF-α and TNFR1, in ETN-treated KK-Ay mice were significantly decreased compared with untreated KK-Ay mice. mRNA levels of ICAM-1, VCAM-1, and monocyte chemoattractant protein-1 and the number of F4/80-positive cells were all decreased after treatment. Numbers of cleaved caspase-3- and TUNEL-positive cells in untreated mice were very few and were not different from ETN-treated mice. In vitro, stimulation with TNF-α or HG markedly increased both mRNA levels of TNFRs, unlike in the in vivo case. Furthermore, ETN partly recovered TNF-α-induced but not HG-induced TNFR mRNA levels. In conclusion, it appears that ETN may improve the progression of the early stage of DN predominantly through inhibition of the anti-inflammatory action of the TNF-α-TNFR2 pathway.

scholarly journals Elucidating the role of pigment epithelium-derived factor (PEDF) in metabolic PCOS models

2020 ◽  
Vol 244 (2) ◽  
pp. 297-308 ◽  
Author(s):  
Michal Silber ◽  
Irit Miller ◽  
Hadas Bar-Joseph ◽  
Ido Ben-Ami ◽  
Ruth Shalgi
Keyword(s):  
Pigment Epithelium ◽  
Elevated Serum ◽  
Female Offspring ◽  
Mrna Levels ◽  
Prolonged Incubation ◽  
Protein Levels ◽  
Potential Therapeutic Role ◽  
Endothelial Growth Factor

PCOS is the most common endocrinopathy in women; associated with obesity and insulin resistance (IR). IR leads to accumulation of advanced-glycation-end-products (AGEs) and their receptor, RAGE. PCOS patients have increased levels of vascular endothelial growth factor (VEGF), interleukin 6/8 (IL-6/8) and anti-Mϋllerian-hormone (AMH). PEDF is a secreted-glycoprotein known for its anti-angiogenic and anti-inflammatory properties. We aimed to elucidate the role of PEDF in the pathogenesis and treatment of PCOS. We used a prenatal PCOS mouse model and fed the female offspring a high-fat diet, inducing metabolic PCOS (met.PCOS) characteristics. Female offspring were divided into three groups: control; met.PCOS; met.PCOS + recombinant PEDF (rPEDF). Met.PCOS mice gained more weight, had elevated serum IL-6 and higher mRNA levels of AMH, PEDF and RAGE in their granulosa cells (GCs) than met.PCOS + rPEDF mice. An in vitro Met.PCOS model in human GCs (KGN) line was induced by prolonged incubation with insulin/AGEs, causing development of IR. Under the same conditions, we observed an elevation of VEGF, IL-6/8 mRNAs, concomitantly with an increase in PEDF mRNA, intracellular protein levels, and an elevation of PEDF receptors (PEDF-Rs) mRNA and protein. Simultaneously, a reduction in the secretion of PEDF from GCs, was measured in the medium. The addition of rPEDF (5 nM) activated P38 signaling, implying that PEDF-Rs maintained functionality, and negated AGE-induced elevation of IL-6/8 and VEGF mRNAs. Decreased PEDF secretion may be a major contributor to hyperangiogenesis and chronic inflammation, which lie at the core of PCOS pathogenesis. rPEDF treatment may restore physiological angiogenesis inflammatory balance, thus suggesting a potential therapeutic role in PCOS.

255 GENE EXPRESSION OF Cox 5a, 5b, AND 6b1 AND THEIR ROLES IN PRE-IMPLANTATION OF MOUSE EMBRYOS

2006 ◽  
Vol 18 (2) ◽  
pp. 235
Author(s):  
S.-E. Lee ◽  
X.-Y. Li ◽  
X.-S. Cui ◽  
N.-H. Kim
Keyword(s):  
Rna Interference ◽  
Mrna Expression ◽  
Real Time ◽  
Oocyte Maturation ◽  
Blastocyst Stage ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Target Mrna ◽  
Protein Levels

Despite clear evidence of regulation of mitochondrial respiration by nuclear encoded genes, cytochrome oxidase (Cox), little information is available on their expression and functional roles during early embryonic development. To examine the role of Cox in oocyte maturation and embryogenesis, we first characterized mRNA and protein levels of nuclear encoded genes, Cox 5a, 5b, and 6b1, in mouse oocytes and during early embryogenesis, using real-time RT-PCR and immunocytochemistry. We then examined the possible role of these genes in oocyte maturation and pre-implantation development using RNA interference analysis. The relative abundances of Cox 5a, 5b, and 6b1 transcripts was measured by real time RT-PCR. After normalization by comparison to histone H2a mRNA levels, the mRNA expression of Cox 5a, 5b, and 6b1 were found to be considerable in mature oocytes and zygotes, but reduced slightly in 2-cell embryos. From the 2-cell to the blastocyst stage, mRNA expression is dependent on the number of blastomeres, as expression increases only gradually with development. Immunocytochemical studies revealed that Cox 5a, 5b, and 6b1 proteins were expressed in all blastomeres of the blastocyst. Injection of Cox 5a, 5b, or 6b1 siRNA into GV stage oocytes decreased expression of the target mRNA specifically, while not affecting the expression of mRNAs for the other subunits in mature oocytes. Similarly, each siRNA injection into zygotes specifically reduced target mRNA expression at the 2-cell, morula and blastocyst stages (P < 0.05). Silencing of mRNA expression by RNA interference (siRNA) did not inhibit oocyte maturation or developmental events up to the morula and blastocyst stages. The expression level of mtDNA9, as well as overall levels of mitochondrial mRNAs, was not different following injection of siRNA for Cox 5a, 5b, or 6b1. However, it is evident that the number of mitochondria in siRNA treated blastocysts was greatly reduced, and they appeared to be morphologically abnormal. Significantly higher apoptosis and lower cell numbers were observed in siRNA treated blastocysts. Real time RT PCR revealed that silencing of Cox 5a, 5b, and 6b1 decreased mRNA and protein levels of E-cadherin. These results suggest that the Cox subunits, Cox 5a, 5b, and 6b1, play an important role in mitochondrial function during pre-implantation development. This work was funded by a grant from the National Research Laboratory Program in Korea.

C-Cbl Regulates c-Mpl Receptor Trafficking and Its Internalization

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2388-2388
Author(s):  
Sebastian Jonas Saur ◽  
Melanie Märklin ◽  
Manuela Ganser ◽  
Kyle Hoehn ◽  
James E David ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Plasma Levels ◽  
Thrombus Formation ◽  
Surface Expression ◽  
Mrna Levels ◽  
Wild Type ◽  
Primary Mouse

Abstract Megakaryopoiesis is controlled by a variety of hematopoietic growth factors and cytokines in order to maintain physiological levels of circulating platelets. Thrombopoietin (TPO) signalling via its receptor c-Mpl is a key regulator of megakaryopoiesis driving megakaryocyte differentiation, promoting endomitosis and proplatelet formation. Therefore TPO/c-Mpl signalling needs to be tightly regulated to maintain physiological megakaryopoiesis. One of the most effective mechanisms to permanently disable activated signalling proteins is by targeted degradation via lysosomes or proteasomes. Previous studies have identified c-Cbl as an E3 ligase responsible for the ubiquitination of c-Mpl in cell lines. In this study, we investigated the mechanisms of TPO-mediated c-Mpl degradation in primary mouse cells. In order to determine the potential role of c-Cbl in murine megakaryopoiesis we used a conditional PF4-Cre c-Cbl knockout (ko) mouse model to specifically delete c-Cbl in the megakaryocytic lineage. Megakaryocytes were generated in vitro by culturing bone marrow from WT and PF4-Cre/c-Cbl-floxed (c-Cbl ko) lines for 72 hrs in the presence of rmTPO. C-Cbl ko mice showed significant bone marrow megakaryocyte hyperplasia, however megakaryocyte numbers in the spleen remained unchanged. Platelets counts were significantly elevated as compared to control mice (1.2 x106 vs. 1.7x106 p=0.0001) and in addition, the platelets from the c-Cbl ko mouse strain were of significantly smaller size (43 vs. 38 fL, p=0.0022). Using a method of in vivo double labelling of platelets, we were able to simultaneously follow the survival of both the entire population of platelets and new platelets which were generated during the last 24 hours. There were more new platelets produced within a 24 h period in the c-Cbl ko mice although the half-life of platelets was similar in the both cohorts. Although c-Cbl ko mice exhibited thrombocytosis, they showed a severe defect in thrombus formation using an in vivo thrombus formation model with Fe3Cl. TPO plasma levels, known to be inversely regulated by circulating platelet numbers, were surprisingly increased (250 vs. 420 pg/ml, p=0.005) in the c-Cbl ko mice. There was no difference in liver mRNA levels in the two cohorts. We therefore looked at c-Mpl protein and mRNA expression in megakaryocytes and found c-Cbl ko mice to express more c-Mpl compared with wild type controls. Surprisingly, we found c-Mpl surface expression to be reduced and internalization of the receptor significantly impaired following TPO stimulation in c-Cbl ko mice. Incubating platelets in vitro with TPO for 2 hours to evaluate the TPO uptake capacity of platelets, we found c-Cbl ko platelets to show a severe uptake defect compared with wild type control platelets. Taken together, we have successfully ablated c-Cbl specifically from the megakaryocyte lineage and demonstrated that this has profound effects on platelet counts and size. In addition, we showed that c-Cbl ablation leads to reduced c-Mpl surface expression and impaired internalization, which culminates in increased TPO plasma levels causing increased megakaryopoiesis in the c-Cbl ko mice. In summary, our data enhance our understanding of the regulation of TPO signalling and the physiological role of c-Cbl in the megakaryocytic lineage. Disclosures No relevant conflicts of interest to declare.

Expression of Lipoprotein Lipase In Chronic Lymphocytic Leukemia Cells: Is There a Biological Function?

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3580-3580
Author(s):  
Edit anna Porpaczy ◽  
Stefanie Tauber ◽  
Martin Bilban ◽  
Gerhard Kostner ◽  
Michaela Gruber ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Cell Survival ◽  
Mrna Expression ◽  
Lipoprotein Lipase ◽  
Cell Lines ◽  
Knock Down ◽  
Protein Levels ◽  
Healthy Donors

Abstract Abstract 3580 The expression of lipoprotein lipase (LPL) in CLL cells is an established mRNA surrogate marker for immunoglobulin heavy chain (IgVH) mutational status. High expression of LPL correlates with poor prognosis. However, the possible functional role of LPL in CLL is still unclear. LPL is normally expressed in muscle cells, adipose tissue and macrophages, transported to the luminal surface of endothelial cells where it is bound heparan sulfate-proteoglycans (HSPG). Heparin competes with HSPG for the binding sites and intravenous injection leads to elevated plasma LPL protein levels and enzymatic activity (“heparin release test”). LPL mRNA levels correlate with intracellular protein expression (Heintel et al. Leukemia. 2005; Mansouri et al. Leuk Res. 2010). Moreover cellular lysates from CLL patients contain elevated LPL enzymatic activity compared to healthy donors (Pallasch et al. Leukemia. 2008.). In this study, we investigated the basal (pre-heparin) LPL protein levels by enzyme-linked immunosorbent assay in the serum of 42 CLL patients, 14 non-CLL patients (lymphoma in remission), and 4 healthy donors (HD): Median pre-heparin LPL protein levels were 40.10 ng/ml (range: 5.66–108.44), 44.11 ng/ml (18.26-84.08), and 68.14 ng/ml (33.28-174.38), respectively. Among CLL patients there were no significant differences between those with high (N=16; median LPL protein in serum: 38.10 ng/ml (8.72-73.49)) and low (N=26; 43.12 ng/ml (5.66-108.44) (p=0.354) LPL mRNA expression. Thirteen patients with known LPL mRNA expression were investigated for LPL protein “release” after heparin injection. Ten and twenty minutes after 50 U/kg heparin injection, the elevation of both parameters, LPL protein amount in serum and enzymatic activity in plasma, was similar to those of HD normal values. In detail, medium serum protein levels in samples with high LPL mRNA (N=5) increased from 16.11 to 214.33 and 332.78 ng/ml and in the samples with low mRNA (N=8) from 13.08 to 219.68 and 386.65 ng/ml, respectively. The corresponding median values of the LPL enzymatic activities in high vs. low expressors were: 7.25/15.52/20.01 and 7.45/19.13/20.57 μ M/ml/h. In addition, release of LPL from peripheral mononuclear cells (PBMC) of CLL patients (N=3) by heparin in vitro was absent. Cell viability and LPL mRNA expression remained unaffected in both in vivo and in vitro samples after heparin addition. In order to assess the impact of LPL on cell survival, CLL cells were cultured (N=3) for up to 72 hours with different doses of purified LPL protein. There was no positive effect on cell survival irrespective of primary LPL mRNA expression or culture conditions (with or without FCS). Since these results point to an intracellular effect of LPL, we aimed to identify downstream targets by knock down with siRNA against LPL in 7 CLL samples and 5 cell lines (hepatocellular carcinoma, cervix carcinoma, colon carcinoma, multiple myeloma and acute monocytic leukemia) with high LPL mRNA expression. Gene expression changes were analyzed by microarrays (GeneChip® Human Gene 1.0 ST Array, Affymetrix). Fifteen genes were up- (N=4) or downregulated (N=11) in at least 3 of 5 cell lines by more than 1.5-fold (e.g. GSTP1, COROC1). Nine genes were at least 1.5-fold downregulated in parallel with LPL in the CLL samples only. These genes belong to various pathways (e.g. cell cycle, signaling in immune system, metabolism of carbohydrates) and seem to be specific for CLL. Cross-validation of individual genes is under way. Our data suggest that (1) neither basal serum LPL protein levels nor heparin-induced LPL release in CLL patients are suitable clinical prognostic markers; (2) Stimulation with external LPL protein does not affect CLL cell survival; (3) siRNA knock-down of LPL induces changes in various functional pathways. We conclude that the key role of LPL expression in high-risk CLL is related to its (intra)cellular expression. Disclosures: No relevant conflicts of interest to declare.

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