Project description:Previously, we reported apolipoprotein A-I (apoA-I), the major protein component of high-density lipoprotein (HDL) has potent anti-melanoma activity. Herein, we used DNA microarray and bioinformatics to interrogate gene expression profiles of tumors from apoA-I expressing (A-I Tg+/-) versus apoA-I-null (A-I KO) animals to gain insights into mechanisms of apoA-I tumor protection. Differential expression analyses of 11 distinct tumors per group with > 1.2-fold cut off and a false discovery rate adjusted p< 0.05, identified 176 significant transcripts (71 up- and 105 down-regulated in A-I Tg+/- relative to A-I KO group). Bioinformatic analyses identified the mevalonate and de novo serine/glycine synthesis pathways as potential targets for apoA-I anti-tumor activity. Relative to A-I KO, day-7 B16F10L melanoma tumor homografts from A-I Tg+/- exhibited reduced expression of mevalonate-5-pyrophosphate decarboxylase (MVD), a key enzyme targeted in cancer therapy, as well as squalene epoxidase (Sqle), cytochrome P450, family 51 (Cyp51), hydroxysteroid (17-beta) dehydrogenase 7 (Hsd17b7), and 24-dehydrocholesterol reductase (Dhcr24) with the latter four serving in the sterol synthesis arm of the mevalonate pathway. Phosphoglycerate dehydrogenase (Phgdh), the first enzyme branching off glycolysis in de novo serine synthesis pathway was the most repressed transcript in tumors from A-I Tg+/-. We validated the experimental approach by correlating gene expression patterns in a mouse model where A-I KO is tumor-permissive relative to A-I Tg+/-, with adverse tumor markers previously identified in human melanoma and found 45% concordance. We propose that apoA-I, a physiological serum protein may target the mevalonate and serine synthesis pathways in melanoma cells, in vivo, thus inhibiting the flux of building blocks for macromolecule synthesis that drive rapid tumor growth.
Project description:Previously, we reported apolipoprotein A-I (apoA-I), the major protein component of high-density lipoprotein (HDL), has potent anti-melanoma activity. We used DNA microarray and bioinformatics to interrogate gene expression profiles of tumors from apoA-I expressing (A-I Tg+/-) versus apoA-I-null (A-I KO) animals to gain insights into mechanisms of apoA-I tumor protection. Differential expression analyses of 11 distinct tumors per group with > 1.2-fold cut-off and a false discovery rate adjusted p < 0.05, identified 176 significant transcripts (71 upregulated and 105 downregulated in A-I Tg+/- versus A-I KO group). Bioinformatic analyses identified the mevalonate and de novo serine/glycine synthesis pathways as potential targets for apoA-I anti-tumor activity. Relative to A-I KO, day 7 B16F10L melanoma tumor homografts from A-I Tg+/- exhibited reduced expression of mevalonate-5-pyrophosphate decarboxylase (Mvd), a key enzyme targeted in cancer therapy, along with a number of key genes in the sterol synthesis arm of the mevalonate pathway. Phosphoglycerate dehydrogenase (Phgdh), the first enzyme branching off glycolysis into the de novo serine synthesis pathway, was the most repressed transcript in tumors from A-I Tg+/-. We validated our mouse tumor studies by comparing the significant transcripts with adverse tumor markers previously identified in human melanoma and found 45% concordance. Our findings suggest apoA-I targets the mevalonate and serine synthesis pathways in melanoma cells in vivo, thus providing anti-tumor metabolic effects by inhibiting the flux of biomolecular building blocks for macromolecule synthesis that drive rapid tumor growth.
Project description:Apolipoprotein A-I mimetic peptides are amphipathic alpha helix peptides that display similar functions to apolipoprotein A-I, and preclinical studies have evaluated . In this study, we evaluated the effect of the long-term expression of L37pA in the liver by an adeno-associated virus (AAV-L37pA) on the expression of an adeno-associated virus encoding interferon-alpha (AAV-IFNα). Long-term IFNα expression in the liver leads to lethal hematological toxicity one month after AAV administration. Concomitant administration of AAV-L37pA prevented the lethal toxicity since the IFNα expression was reduced one month after AAV administration by decreasing the expression of IFNα. To identify the mechanism of action of L37pA, a genomic and proteomic analysis was performed fifteen days after AAV administration when a similar level of IFNα and interferon-stimulated genes were observed in mice treated with AAV-IFNα alone and in mice treated with AAV-IFNα and AAV-L37pA. The coexpression of the apolipoprotein A-I mimetic peptide L37pA with IFNα modulated the gene expression program of IFNα, inducing a significant reduction in inflammatory pathways affecting pathogen-associated molecular patterns receptor, dendritic cells, NK cells and Th1 immune response. The proteomic analysis confirmed the impact of the L37pA activity on several inflammatory pathways and indicated an activation of LXR/RXR and PPPARα/γ nuclear receptors. Thus, long-term expression of L37pA induces an anti-inflammatory effect in the liver that allows silencing of IFNα expression mediated by an adeno-associated virus.
Project description:Fucoidan, a sulfated polysaccharide extracted from brown seaweeds, possesses many biological activities including anti-inflammatory and anti-oxidant activities. We aimed to investigate the protective effects of fucoidan on dyslipidemia and atherosclerosis in apolipoprotein E-deficient mice (ApoEshl mice) and to elucidate its molecular targets in the liver by using a transcriptomic approach. For 12 weeks, ApoEshl mice were fed a high-fat diet (HFD) supplemented with either 1% or 5% fucoidan. Fucoidan supplementation significantly reduced tissue weight (liver and white adipose tissue), blood lipid, total-cholesterol (TC), triglyceride (TG), non-high density lipoprotein-cholesterol (Non-HDL-C), and glucose levels in HFD-fed ApoEshl mice but increased plasma lipoprotein lipase (LPL) activity and HDL-C levels. Fucoidan also reduced hepatic steatosis levels (liver size, TC and TG levels, and lipid peroxidation) and increased white adipose tissue LPL activity. DNA microarray analysis and quantitative reverse transcription-polymerase chain reaction demonstrated differential expression of genes encoding proteins involved in lipid metabolism, energy homeostasis, and insulin sensitivity, by activating Ppara and inactivating Srebf1. Fucoidan supplementation markedly reduced the thickness of the lipid-rich plaque, lipid peroxidation, and foaming macrophage accumulation in the aorta in HFD-fed ApoEshl mice. Thus, fucoidan supplementation appears to have anti-dyslipidemic and anti-atherosclerotic effects by inducing LPL activity and inhibiting the effects of inflammation and oxidative stress in HFD-fed ApoEshl mice.
Project description:The anti-diabetic drug and agonist of the peroxisome proliferator-activated receptor gamma (Pparg), rosiglitazone, was recently withdrawn in many countries because the drug use was associated with an increased risk of heart failure. To investigate underlying pathomechanisms, we chose 6-month-old apolipoprotein E (apoE)-deficient mice, which are prone to atherosclerosis and insulin resistance, and thereby mimic the risk profile of patients with cardiovascular disease. After 8 weeks of rosiglitazone treatment (30 mg/kg/day), echocardiography and histology analyses demonstrated that rosiglitazone had induced heart failure with cardiac dilation. Concomitantly, cardiac lipid overload and lipid-induced cardiomyocyte death developed. The microarray gene expression study of heart tissue from rosiglitazone-treated apoE-deficient mice relative to untreated apoE-deficient mice and non-transgenic B6 mice identified cardiac Pparg-dependent lipid metabolism genes in rosiglitazone-treated mice, which seem to trigger a major heart failure promoting pathway. Microarray gene expression profiling was performed with heart tissue isolated from three study groups: (i) rosiglitazone-treated 8-month-old apolipoprotein (apoE)-deficient mice with symptoms of heart failure, (ii) untreated 8-month-old apoE-deficient mice, and (iii) age-matched, untreated, non-transgenic B6 control mice.
Project description:Apolipoprotein E deficiency potentiates macrophage resistance to staphylococcus aureus osteomyelitis via regulating cholesterol metabolism
Project description:Apolipoprotein A-I mimetic peptides are amphipathic alpha-helix peptides that display similar functions to apolipoprotein A-I. Preclinical and clinical studies have demonstrated the safety and efficacy of apolipoprotein A-I mimetic peptides in multiple indications associated with inflammatory processes. In this study, we evaluated the effect of the long-term expression of L37pA in the liver by an adeno-associated virus (AAV-L37pA) on the expression of an adeno-associated virus encoding interferon-alpha (AAV-IFNα). Long-term IFNα expression in the liver leads to lethal hematological toxicity one month after AAV administration. Concomitant administration of AAV-L37pA prevented the lethal toxicity since the IFNα expression was reduced one month after AAV administration by decreasing the expression of IFNα. To identify the mechanism of action of L37pA, a genomic and proteomic analysis was performed fifteen days after AAV administration when a similar level of IFNα and interferon-stimulated genes were observed in mice treated with AAV-IFNα alone and in mice treated with AAV-IFNα and AAV-L37pA. The coexpression of the apolipoprotein A-I mimetic peptide L37pA with IFNα modulated the gene expression program of IFNα, inducing a significant reduction in inflammatory pathways affecting pathogen-associated molecular patterns receptor, dendritic cells, NK cells and Th1 immune response. The proteomic analysis confirmed the impact of the L37pA activity on several inflammatory pathways and indicated an activation of LXR/RXR and PPPARα/γ nuclear receptors. Thus, long-term expression of L37pA induces an anti-inflammatory effect in the liver that allows silencing of IFNα expression mediated by an adeno-associated virus.