High plasma triglyceride (TG) level is a major independent risk factor of coronary heart disease. A newly identified Apolipoprotein A5 (Apoa5) gene has been shown to play an important role in determining plasma TG concentrations in humans and mice. Prague hereditary hypertriglyceridemic (HTG) rats are a useful model of human hypertriglyceridemia and other symptoms of metabolic syndrome. Thus, the variation of Apoa5 gene and its expression were studied in this strain under normal conditions and after chronic fructose loading. Lewis and Wistar rats served as normotriglyceridemic controls. Plasma TG were significantly higher in HTG rats in comparison with both control strains. Sequence analysis of the rat Apoa5 gene revealed the existence of two introns. However, screening of the coding regions and intron-exon boundaries of Apoa5 gene did not indicate any mutation of this gene in HTG rats in comparison with Lewis and Wistar ones. Under the basal conditions the expression of Apoa5 was lower in all age groups of HTG rats compared to Wistar animals. Furthermore, during chronic fructose loading there were no significant changes of Apoa5 expression in HTG rats, although plasma TG levels rose 3-4 times within first two days of fructose loading and were increased during the whole period of fructose treatment. In conclusion, Apoa5 does not seem to be a genetic determinant of hypertriglyceridemia in HTG rats. The absence of significant changes in Apoa5 gene expression during chronic fructose-induced TG elevation excludes its major role in mechanisms compensating severe hypertriglyceridemia.
Leptin and adiponectin, two adipocytokines, may work together in regulating energy homeostasis and insulin action. Leptin gene expression has been investigated in term placental tissue complicated by gestational diabetes mellitus (GDM), but never in conjunction with all isoforms of the leptin receptor (LEPR A-D), or with adiponectin receptors (ADIPOR1 and 2). In this study we examined the association between changes in expression of these genes in placental tissue and GDM risk. We assessed placental gene expression of leptin, LEPR A-D and ADIPOR1 and 2 by real time PCR using mRNA from maternal and fetal biopsies. Tissues were collected from uncomplicated pregnancies (n=28) and those complicated by GDM (n=19). Gene expression was normalized to three endogenous housekeeping genes. Relative gene expression values were reported as fold change between groups. Adiponectin gene expression was out of the sensitive range of our assay. There were increases in leptin mRNA expression in GDM cases compared with controls for maternal-side (p=0.06), and fetal-side (p=0.09) placental biopsies. No significant changes were seen in GDM cases compared with controls in LEPR A-D or ADIPOR1 and 2. mRNA derived from maternal-side tissue was positively correlated with tissue from the fetal side for all genes studied (all p<0.01). Finally, we noted that absence or presence of GDM was a major factor in leptin mRNA expression after adjusting for maternal age, mode of delivery, parity and smoking status. In conclusion, increases in leptin mRNA expression in term placenta, but not that of its receptors, are associated with the diagnosis of GDM. Changes seen in the ligand, but not the receptor, of the leptin pathway in GDM-complicated pregnancies may also apply to the adiponectin pathway, as the ADIPOR1 and 2 mRNAs do not change with GDM diagnosis.
This study evaluated right ventricular (RV) and left ventricular (LV) diastolic tolerance to afterload and SERCA2a, phospholamban and sodium-calcium exchanger (NCX) gene expression in Wistar rats. Time constant and end diastolic pressure-dimension relation (EDPDR) were analyzed in response to progressive RV or LV afterload elevations, induced by beat-to-beat pulmonary trunk or aortic root constrictions, respectively. Afterload elevations decreased LV-, but increased RV-. Whereas LV- analyzed the major course of pressure fall, RV- only assessed the last fourth. Furthermore, RV afterload elevations progressively upward shifted RV EDPDR, whilst LV afterload elevations did not change LV-EDPDR. SERCA2a and phospholamban mRNA were similar in both ventricles. NCX-mRNA was almost 50 % lower in RV than in LV. Left ventricular afterload elevations, therefore, accelerated the pressure fall and did not induce diastolic dysfunction, indicating high LV diastolic tolerance to afterload. On the contrary, RV afterload elevations decelerated the late RV pressure fall and induced diastolic dysfunction, indicating small RV diastolic tolerance to afterload. These results support previous findings relating NCX with late Ca2+ reuptake, late relaxation and diastolic dysfunction.
Hepcidin, a key regulator of iron metabolism, decreases intestinal absorption of iron and its release from macrophages. Iron, anemia, hypoxia, and inflammation were reported to influence hepcidin expression. To investigate regulation of the expression of hepcidin and other iron-related genes, we manipulated erythropoietic activity in mice. Erythropoiesis was inhibited by irradiation or posttransfusion polycythemia and stimulated by phenylhydrazine administration and erythropoietin. Gene expression of hepcidin and other iron-related genes (hemojuvelin, DMT1, ferroportin, transferrin receptors, ferritin) in the liver was measured by the real-time polymerase chain reaction. Hepcidin expression increased despite severe anemia when hematopoiesis was inhibited by irradiation. Suppression of erythropoiesis by posttransfusion polycythemia or irradiation also increased hepcidin mRNA levels. Compensated hemolysis induced by repeated phenylhydrazine administration did not change hepcidin expression. The decrease caused by exogenous erythropoeitin was blocked by postirradi
ation bone marrow suppression. The hemolysis and anemia decrease hepcidin expression only when erythropoiesis is functional; on the other hand, if erythropoiesis is blocked, even severe anemia does not lead to a decrease of hepcidin expression, which is indeed increased. We propose that hepcidin is exclusively sensitive to iron utilization for erythropoiesis and hepatocyte iron balance, and these changes are not sensed by other
genes involved in the control of iron metabolism in the liver.
Summary The aim of the study was to characterize by molecular profiling two glomerular diseases: IgA nephropathy (IgAN) and focal segmental glomerulosclerosis (FSGS) and to identify potential molecular markers of IgAN and FSGS progression. The expressions of 90 immune-related genes were compared in biopsies of patients with IgAN (n=33), FSGS (n=17) and in controls (n=11) using RT-qPCR. To identify markers of disease progression, gene expression was compared between progressors and non-progressors in 1 year follow-up. The results were verified on validation cohort of patients with IgAN (n=8) and in controls (n=6) using laser-capture microdissection, that enables to analyze gene expression separately for glomeruli and interstitium. In comparison to controls, patients with both IgAN and FSGS, had lower expression of BAX (apoptotic molecule BCL2-associated protein) and HMOX-1 (heme oxygenase 1) and higher expression of SELP (selectin P). Furthermore, in IgAN higher expression of PTPRC (protein-tyrosine phosphatase, receptor-type C) and in FSGS higher expression of BCL2L1 (regulator of apoptosis BCL2-like 1) and IL18 compared to control was observed. Validation of differentially expressed genes between IgAN and controls on another cohort using laser-capture microdissection confirmed higher expression of PTPRC in glomeruli of patients with IgAN. The risk of progression in IgAN was associated with higher expression EDN1 (endothelin 1) (AUC=0.77) and FASLG (Fas ligand) (AUC=0.82) and lower expression of VEGF (vascular endothelial growth factor) (AUC=0.8) and in FSGS with lower expression of CCL19 (chemokine (C-C motif) ligand 19) (AUC=0.86). Higher expression of EDN1 and FASLG along with lower expression of VEGF in IgAN and lower expression of CCL19 in FSGS at the time of biopsy can help to identify patients at risk of future disease progression., I. Tycová, P. Hrubá, D. Maixnerová, E. Girmanová, P. Mrázová, L. Straňavová, R. Zachoval, M. Merta, J. Slatinská, M. Kollár, E. Honsová, V. Tesař, O. Viklický., and Seznam literatury
Vascular endothelium plays an essential role in the pathogenesis of vasoocclusion. The changes in the endothelial cell function can be triggered by changes in gene expression caused by interaction with cytokines and blood cells. Using cDNA arrays, we have recently reported complex patterns of gene expression after stimulation of endothelial cells with TNFα and IL-1β. Better understanding of the time course of gene expression changes, their concentration dependence and reversibility after withdrawal of the offending cytokine is essential for successful prevention and therapy of vasoocclusion. Here we present a detailed study of the concentration dependence and time course of gene expression in endothelial cells after their exposure to TNFα and IL-1β. We focus on the adhesion molecules (VCAM-1, ICAM-1, E-selectin) and cytokines (IL-6, GCP-2, MCP-1) that are likely to contribute to vasoocclusion. We report differences in the time course and intensity of their expression and in their response to TNFα and IL-1β stimulation. We demonstrate that expression of the studied genes is upregulated by low TNFα concentrations that better reflect the TNFα levels detected in the plasma of patients developing vasoocclusion. These results help to understand the changes in the endothelium and to design rational prevention and therapy of vasoocclusion.