Drug and Alcohol Rehabilitation: 11?-Hydroxysteroid Dehydrogenase Type 1 Gene Knockout Attenuates Atherosclerosis and in Vivo Foam Cell Formation in Hyperlipidemic apoE(-/-) Mice.

Published February 7, 2013

11?-Hydroxysteroid Dehydrogenase Type 1 Gene Knockout Attenuates Atherosclerosis and In Vivo Foam Cell Formation in Hyperlipidemic apoE(-/-) Mice.

Filed under: Drug and Alcohol Rehabilitation

PLoS One. 2013; 8(2): e53192
García RA, Search DJ, Lupisella JA, Ostrowski J, Guan B, Chen J, Yang WP, Truong A, He A, Zhang R, Yan M, Hellings SE, Gargalovic PS, Ryan CS, Watson LM, Langish RA, Shipkova PA, Carson NL, Taylor JR, Yang R, Psaltis GC, Harrity TW, Robl JA, Gordon DA

Chronic glucocorticoid excess has been linked to increased atherosclerosis and general cardiovascular risk in humans. The enzyme 11?-hydroxysteroid dehydrogenase type 1 (11?HSD1) increases active glucocorticoid levels within tissues by catalyzing the conversion of cortisone to cortisol. Pharmacological inhibition of 11?HSD1 has been shown to reduce atherosclerosis in murine models. However, the cellular and molecular details for this effect have not been elucidated.To examine the role of 11?HSD1 in atherogenesis, 11?HSD1 knockout mice were created on the pro-atherogenic apoE(-/-) background. Following 14 weeks of Western diet, aortic cholesterol levels were reduced 50% in 11?HSD1(-/-)/apoE(-/-) mice vs. 11?HSD1(+/+)/apoE(-/-) mice without changes in plasma cholesterol. Aortic 7-ketocholesterol content was reduced 40% in 11?HSD1(-/-)/apoE(-/-) mice vs. control. In the aortic root, plaque size, necrotic core area and macrophage content were reduced ?30% in 11?HSD1(-/-)/apoE(-/-) mice. Bone marrow transplantation from 11?HSD1(-/-)/apoE(-/-) mice into apoE(-/-) recipients reduced plaque area 39-46% in the thoracic aorta. In vivo foam cell formation was evaluated in thioglycollate-elicited peritoneal macrophages from 11?HSD1(+/+)/apoE(-/-) and 11?HSD1(-/-)/apoE(-/-) mice fed a Western diet for ?5 weeks. Foam cell cholesterol levels were reduced 48% in 11?HSD1(-/-)/apoE(-/-) mice vs. control. Microarray profiling of peritoneal macrophages revealed differential expression of genes involved in inflammation, stress response and energy metabolism. Several toll-like receptors (TLRs) were downregulated in 11?HSD1(-/-)/apoE(-/-) mice including TLR 1, 3 and 4. Cytokine release from 11?HSD1(-/-)/apoE(-/-)-derived peritoneal foam cells was attenuated following challenge with oxidized LDL.These findings suggest that 11?HSD1 inhibition may have the potential to limit plaque development at the vessel wall and regulate foam cell formation independent of changes in plasma lipids. The diminished cytokine response to oxidized LDL stimulation is consistent with the reduction in TLR expression and suggests involvement of 11?HSD1 in modulating binding of pro-atherogenic TLR ligands.
HubMed – drug

ISL1 Protein Transduction Promotes Cardiomyocyte Differentiation from Human Embryonic Stem Cells.

Filed under: Drug and Alcohol Rehabilitation

PLoS One. 2013; 8(1): e55577
Fonoudi H, Yeganeh M, Fattahi F, Ghazizadeh Z, Rassouli H, Alikhani M, Mojarad BA, Baharvand H, Salekdeh GH, Aghdami N

Human embryonic stem cells (hESCs) have the potential to provide an unlimited source of cardiomyocytes, which are invaluable resources for drug or toxicology screening, medical research, and cell therapy. Currently a number of obstacles exist such as the insufficient efficiency of differentiation protocols, which should be overcome before hESC-derived cardiomyocytes can be used for clinical applications. Although the differentiation efficiency can be improved by the genetic manipulation of hESCs to over-express cardiac-specific transcription factors, these differentiated cells are not safe enough to be applied in cell therapy. Protein transduction has been demonstrated as an alternative approach for increasing the efficiency of hESCs differentiation toward cardiomyocytes.We present an efficient protocol for the differentiation of hESCs in suspension by direct introduction of a LIM homeodomain transcription factor, Islet1 (ISL1) recombinant protein into the cells.We found that the highest beating clusters were derived by continuous treatment of hESCs with 40 µg/ml recombinant ISL1 protein during days 1-8 after the initiation of differentiation. The treatment resulted in up to a 3-fold increase in the number of beating areas. In addition, the number of cells that expressed cardiac specific markers (cTnT, CONNEXIN 43, ACTININ, and GATA4) doubled. This protocol was also reproducible for another hESC line.This study has presented a new, efficient, and reproducible procedure for cardiomyocytes differentiation. Our results will pave the way for scaled up and controlled differentiation of hESCs to be used for biomedical applications in a bioreactor culture system.
HubMed – drug

Imatinib Reverses Doxorubicin Resistance by Affecting Activation of STAT3-Dependent NF-?B and HSP27/p38/AKT Pathways and by Inhibiting ABCB1.

Filed under: Drug and Alcohol Rehabilitation

PLoS One. 2013; 8(1): e55509
Sims JT, Ganguly SS, Bennett H, Friend JW, Tepe J, Plattner R

Despite advances in cancer detection and prevention, a diagnosis of metastatic disease remains a death sentence due to the fact that many cancers are either resistant to chemotherapy (conventional or targeted) or develop resistance during treatment, and residual chemoresistant cells are highly metastatic. Metastatic cancer cells resist the effects of chemotherapeutic agents by upregulating drug transporters, which efflux the drugs, and by activating proliferation and survival signaling pathways. Previously, we found that c-Abl and Arg non-receptor tyrosine kinases are activated in breast cancer, melanoma, and glioblastoma cells, and promote cancer progression. In this report, we demonstrate that the c-Abl/Arg inhibitor, imatinib (imatinib mesylate, STI571, Gleevec), reverses intrinsic and acquired resistance to the anthracycline, doxorubicin, by inducing G2/M arrest and promoting apoptosis in cancer cells expressing highly active c-Abl and Arg. Significantly, imatinib prevents intrinsic resistance by promoting doxorubicin-mediated NF-?B/p65 nuclear localization and repression of NF-?B targets in a STAT3-dependent manner, and by preventing activation of a novel STAT3/HSP27/p38/Akt survival pathway. In contrast, imatinib prevents acquired resistance by inhibiting upregulation of the ABC drug transporter, ABCB1, directly inhibiting ABCB1 function, and abrogating survival signaling. Thus, imatinib inhibits multiple novel chemoresistance pathways, which indicates that it may be effective in reversing intrinsic and acquired resistance in cancers containing highly active c-Abl and Arg, a critical step in effectively treating metastatic disease. Furthermore, since imatinib converts a master survival regulator, NF-?B, from a pro-survival into a pro-apoptotic factor, our data suggest that NF-?B inhibitors may be ineffective in sensitizing tumors containing activated c-Abl/Arg to anthracyclines, and instead might antagonize anthracycline-induced apoptosis.
HubMed – drug

Trypanosoma cruzi Response to Sterol Biosynthesis Inhibitors: Morphophysiological Alterations Leading to Cell Death.

Filed under: Drug and Alcohol Rehabilitation

PLoS One. 2013; 8(1): e55497
Kessler RL, Soares MJ, Probst CM, Krieger MA

The protozoan parasite Trypanosoma cruzi displays similarities to fungi in terms of its sterol lipid biosynthesis, as ergosterol and other 24-alkylated sterols are its principal endogenous sterols. The sterol pathway is thus a potential drug target for the treatment of Chagas disease. We describe here a comparative study of the growth inhibition, ultrastructural and physiological changes leading to the death of T. cruzi cells following treatment with the sterol biosynthesis inhibitors (SBIs) ketoconazole and lovastatin. We first calculated the drug concentration inhibiting epimastigote growth by 50% (EC(50)/72 h) or killing all cells within 24 hours (EC(100)/24 h). Incubation with inhibitors at the EC(50)/72 h resulted in interesting morphological changes: intense proliferation of the inner mitochondrial membrane, which was corroborated by flow cytometry and confocal microscopy of the parasites stained with rhodamine 123, and strong swelling of the reservosomes, which was confirmed by acridine orange staining. These changes to the mitochondria and reservosomes may reflect the involvement of these organelles in ergosterol biosynthesis or the progressive autophagic process culminating in cell lysis after 6 to 7 days of treatment with SBIs at the EC(50)/72 h. By contrast, treatment with SBIs at the EC(100)/24 h resulted in rapid cell death with a necrotic phenotype: time-dependent cytosolic calcium overload, mitochondrial depolarization and reservosome membrane permeabilization (RMP), culminating in cell lysis after a few hours of drug exposure. We provide the first demonstration that RMP constitutes the “point of no return” in the cell death cascade, and propose a model for the necrotic cell death of T. cruzi. Thus, SBIs trigger cell death by different mechanisms, depending on the dose used, in T. cruzi. These findings shed new light on ergosterol biosynthesis and the mechanisms of programmed cell death in this ancient protozoan parasite.
HubMed – drug

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