Down-regulation of single-stranded DNA-binding protein 1 expression induced by HCMV infection promotes lipid accumulation in cells

The objective of this study was to observe the infection of human cytomegalovirus (HCMV) to human umbilical vein endothelial cells, and its effect on the expression of single-stranded DNA-binding protein (SSBP1) and on lipid metabolism in endothelial cells. We screened the differential expression of mRNAs after HCMV infection by suppression subtractive hybridization and the expression levels of SSBP1 mRNA and protein after HCMV infection by real-time PCR and western blot. After verification of successful infection by indirect immunofluorescent staining and RT-PCR, we found a differential expression of lipid metabolism-related genes including LDLR, SCARB, CETP, HMGCR, ApoB and LPL induced by HCMV infection. The expression levels of SSBP1 mRNA and protein after HCMV infection were significantly down-regulated. Furthermore, we found that upregulation of SSBP1 inhibited the expression of atherosclerosis-associated LDLR, SCARB, HMGCR, CETP as well as the accumulation of lipids in the cells. The results showed that the inhibition of SSBP1 by HCMV infection promotes lipid accumulation in the cells.

Transferências lipídicas para HDL em diabéticos tipo 2: associações com microalbuminúria, estatina e insulina / Transferencias lipídicas hacia HDL en diabéticos tipo 2: asociaciones con microalbuminuria, estatina y insulina / Lipid transfer to HDL in type-2 diabetic patients: associations with microalbuminuria, statin, and insulin

FUNDAMENTO: O diabete melito tipo 2 (DM2) é um fator de risco isolado para coronariopatia, principalmente quando associado à microalbuminúria (MA). Alterações estruturais e funcionais das lipoproteínas não são totalmente esclarecidas nesse contexto. OBJETIVO: Avaliar a transferência de lípides para HDL (T) em pacientes DM2 e a associação com a presença da MA e com o tratamento com estatina ou insulina. MÉTODOS: Estudamos 33 pacientes com DM2 e 34 controles pareados para idade. Uma nanoemulsão lipídica artificial radiomarcada com ³H-Triglicéride (TG) e 14C-colesterol livre (CL) ou ³H-colesterol éster (CE) e 14C-fosfolípide (FL) foi incubada com plasma. A nanoemulsão e as lipoproteínas foram precipitadas, exceto a HDL, que teve sua radioatividade contada. RESULTADOS: A TFL ( por cento) foi maior no grupo com DM2 que no grupo-controle (25,2±3,2 e 19,7±3,2 respectivamente; p < 0,001), assim como a TCL ( por cento): 9,1±2,7 e 6,3±1,5 respectivamente; p < 0,001. O diagnóstico de MA não se associou a mudanças da propriedade de transferência. O uso da insulina associou-se à menor TFL ( por cento): 23,5±2,1 contra 26,1±3,3; p = 0,018. Já o uso da estatina associou-se à queda de todas - TCE ( por cento): 3,5±0,9; TFL ( por cento):23,8±2,0; TTG ( por cento): 3,9±0,8; TCL ( por cento):7,4±1,3 - quando comparado ao grupo que não usava estatina (TCE ( por cento):5,9±2,4; TFL ( por cento):26,9±3,6; TTG ( por cento):6,4±2,2; TCL ( por cento):11,1±2,6). CONCLUSÃO: O DM2 aumentou a transferência de lípides de superfície para HDL, enquanto o uso de estatina diminuiu todas as transferências de lípides. A presença de MA não se associou às alterações das transferências de lípides.

BACKGROUND: Type-2 diabetes mellitus (T2DM) is an isolated risk factor for coronary artery disease, especially when associated with microalbuminuria (MA). Structural and functional changes in lipoproteins have not yet been fully elucidated in this context. OBJECTIVE: To assess lipid transfer (T) to HDL in type-2 diabetic patients and its association with microalbuminuria and treatment with statins or insulin. METHODS: Thirty-three patients with type-2 diabetes mellitus and 34 age-matched control subjects were studied. A synthetic cholesterol-rich nanoemulsion radiolabeled with ³H- triglycerides (TG) and 14C-free cholesterol (FC) or ³H- cholesteryl ester (CE) and 14C-phospholipids (PL) was incubated with plasma. Both the nanoemulsion and lipoproteins were precipitated, except for HDL, which was counted for radioactivity. RESULTS: PLT ( percent) was higher in the T2DM group than in the control group (25.2 ± 3.2 and 19.7 ± 3.2 respectively; p < 0.001), as was free cholesterol ( percent FC): 9.1 ± 2.7 and 6.3 ± 1.5 respectively; p < 0.001. The diagnosis of microalbuminuria (MA) was not associated with changes in lipid transfers. Insulin therapy was associated with lower PLT rates: 23.5 ± 2.1 versus 26.1 ± 3.3; p = 0.018. Statin therapy, in turn, was associated with a drop in all lipid transfers - CET 3.5 ± 0.9; PLT: 23.8 ± 2.0; TGT: 3.9 ± 0.8; FCT: 7.4 ± 1.3 - as compared to the group that was not on statin therapy (CET: 5.9 ± 2.4; PLT: 26.9 ± 3.6; TGT: 6.4 ± 2.2; FCT: 11.1 ± 2.6). CONCLUSION:Type-2 diabetes mellitus increased lipid transfer to HDL particles, whereas statin therapy decreased all lipid transfers. The presence of MA was not associated with changes in lipid transfer.

FUNDAMENTO: La diabetes mellitus tipo 2 (DM2) es un factor de riesgo aislado para coronariopatía, principalmente cuando asociado a la microalbuminuria (MA). Alteraciones estructurales y funcionales de las lipoproteínas no están totalmente aclaradas en ese contexto. OBJETIVO: Evaluar no sólo la transferencia de lípidos hacia HDL (T) en pacientes DM2, sino también la asociación tanto con la presencia de la MA como con el tratamiento con estatina o insulina. MÉTODOS: Estudiamos a 33 pacientes con DM2 y 34 controles pareados para edad. Se incubó con plasma una nanoemulsión lipídica artificial radiomarcada con ³H-Triglicérido (TG) y 14C-colesterol libre (CL) o ³H-colesterol esterificado (CE) y 14C-fosfolípido (FL). Se procedió a la precipitación de la nanoemulsión y de las lipoproteínas, con excepción de la HDL, que tuvo su radioactividad contada. RESULTADOS: El valor de TFL ( por ciento) resultó mayor en el grupo con DM2 en confrontación con el grupo-control (25,2±3,2 y 19,7±3,2 respectivamente; p < 0,001); la TCL ( por ciento), por su vez, obtuvo los siguientes resultados: 9,1±2,7 y 6,3±1,5 respectivamente; p < 0,001. El diagnóstico de MA no se asoció a cambios de la propiedad de transferencia. El uso de la insulina se asoció al menor valor de TFL ( por ciento): 23,5±2,1 vs 26,1±3,3; p = 0,018. Ya el uso de la estatina se asoció a la baja del valor de todas las lipoproteínas - TCE ( por ciento): 3,5±0,9; TFL ( por ciento):23,8±2,0; TTG ( por ciento): 3,9±0,8; TCL ( por ciento):7,4±1,3 - si comparado al grupo que no usaba estatina (TCE ( por ciento):5,9±2,4; TFL ( por ciento):26,9±3,6; TTG ( por ciento):6,4±2,2; TCL ( por ciento):11,1±2,6). CONCLUSIONES: El DM2 aumentó la transferencia de lípidos de superficie hacia HDL, mientras que el uso de estatina disminuyó todas las transferencias de lípidos. La presencia de MA no se asoció a las alteraciones de las transferencias de lípidos.

Atherosclerosis in aged mice over-expressing the reverse cholesterol transport genes

We determined whether over-expression of one of the three genes involved in reverse cholesterol transport, apolipoprotein (apo) AI, lecithin-cholesterol acyl transferase (LCAT) and cholesteryl ester transfer protein (CETP), or of their combinations influenced the development of diet-induced atherosclerosis. Eight genotypic groups of mice were studied (AI, LCAT, CETP, LCAT/AI, CETP/AI, LCAT/CETP, LCAT/AI/CETP, and non-transgenic) after four months on an atherogenic diet. The extent of atherosclerosis was assessed by morphometric analysis of lipid-stained areas in the aortic roots. The relative influence (R²) of genotype, sex, total cholesterol, and its main sub-fraction levels on atherosclerotic lesion size was determined by multiple linear regression analysis. Whereas apo AI (R² = 0.22, P < 0.001) and CETP (R² = 0.13, P < 0.01) expression reduced lesion size, the LCAT (R² = 0.16, P < 0.005) and LCAT/AI (R² = 0.13, P < 0.003) genotypes had the opposite effect. Logistic regression analysis revealed that the risk of developing atherosclerotic lesions greater than the 50th percentile was 4.3-fold lower for the apo AI transgenic mice than for non-transgenic mice, and was 3.0-fold lower for male than for female mice. These results show that apo AI overexpression decreased the risk of developing large atherosclerotic lesions but was not sufficient to reduce the atherogenic effect of LCAT when both transgenes were co-expressed. On the other hand, CETP expression was sufficient to eliminate the deleterious effect of LCAT and LCAT/AI overexpression. Therefore, increasing each step of the reverse cholesterol transport per se does not necessarily imply protection against atherosclerosis while CETP expression can change specific athero genic scenarios.