We present data supporting the hypothesis that the lysosomalautophagy pathway is involved in the degradation of intracellular triacylglycerols in the liver. In primary hepatocytes cultivated in the absence of exogenous fatty acids (FFA), both inhibition of autophagy flux (asparagine) or lysosomal activity (chloroquine) decreased secretion of VLDL (very low density lipoproteins) and formation of FFA oxidative products while the stimulation of autophagy by rapamycine increased some of these parameters. Effect of rapamycine was completely abolished by inactivation of lysosomes. Similarly, when autophagic activity was influenced by cultivating the hepatocytes in “starving” (amino-acid poor medium) or “fed” (serum-supplemented medium) conditions, VLDL secretion and FFA oxidation mirrored the changes in autophagy being higher in starvation and lower in fed state. Autophagy inhibition as well as lysosomal inactivation depressed FFA and DAG (diacylglycerol) formation in liver slices in vitro. In vivo, intensity of lysosomal lipid degradation depends on the formation of autophagolysosomes, i.e. structures bringing the substrate for degradation and lysosomal enzymes into contact. We demonstrated that lysosomal lipase (LAL) activity in liver autophagolysosomal fraction was up-regulated in fasting and down-regulated in fed state together with the increased translocation of LAL and LAMP2 proteins from lysosomal pool to this fraction. Changes in autophagy intensity (LC3-II/LC3-I ratio) followed a similar pattern., V. Škop ... [et al.]., and Obsahuje seznam literatury
The abnormal proliferation of vascular smooth muscle cells (VSMC) is thought to play a role in the pathogenesis of atherosclerosis. Adipocytes produce several bioactive paracrine substances that can affect the growth and migration of VSMCs. Our study focuses on the direct effect of the bioactive substances in conditioned media (CM) that was obtained by incubation with primary adipocyte-derived cell lines, including cell lines derived from both preadipocytes and from more mature cells, on the proliferation rate of human aortic smooth muscle cells (HAoSMCs). We used a Luminex assay to measure the adipokine content of the CM and showed that there was a higher concentration of monocyte chemoattractant protein-1 in renal preadipocyte-CM compared with the HAoSMC control (p<0.5). The addition of both renal preadipocyte- and epicardial adipocyte-CM resulted in the elevated production of vascular endothelial growth factor compared with the control HASoSMC CM (p<0.001). The adiponectin content in renal adipocyte-CM was increased compared to all the remaining adipocyte-CM (p<0.01). Moreover, the results showed a higher proliferation rate of HAoSMCs after co-culture with epicardial adipocyte-CM compared to the HAoSMC control (p<0.05). These results suggest that bioactive substances produced by adipocytes have a stimulatory effect on the proliferation of VSMCs., J. Ždychová, S. Čejsková, I. Králová Lesná, A. Králová, J. Malušková, L. Janoušek, L. Kazdová., and Obsahuje bibliografii
Atherosclerosis pathology is the interplay between high intrav ascular LDL particle concentration and monocyte/ macrophage presence within the sub -endothelial space of the artery. In this project, phenotypes of macrophages connected with subclinical inflammation in adipose tissue of living kidney donors were studied. Samples of subcutaneous adipose tissue of living kidney donors (n=36) were exposed to collagenase. Stromal vascular fraction (SVF) was eluted from the samples, then labeled with monoclonal antibodies (anti- CD14 and anti -calprotectin), conjugated with fluo rochromes and analy zed by flow cytometry. The positive correlation between the number of total macrophages and calprotectin- positive macrophages with BMI in the subcutaneous adipose tissue of postmenopausal women was demonstrated (p<0.05; R=0.43 and p<0.01 ; R=0.60), whereas no positive correlation in premenopausal women and men was shown. In conclusion, we documented a significant effect of BMI increase on the presence of total macrophages in adipose tissue of postmenopausal women, in contrast to premenopausal women. This difference was much more pronounced when proinflammatory macrophages with membrane- bound calprotectin were analyzed., A. Králová, I. Králová Lesná, J. Froněk, S. Čejková, A. Sekerková, L. Janoušek, F. Thieme, I. Stříž, J. Ždychová, R. Poledne., and Obsahuje bibliografii
Inflammatory changes, both in the arterial wall and adipose tissue, play a crucial role in the development of atherosclerosis. We measured the gene expression of tumor necrosis factor-alpha (TNFα), monocyte chemoattractant protein-1 (MCP-1), and interleukin 6 (IL-6) in adipose tissue (AT) of living kidney donors (LKD) and patients with peripheral arterial disease (PAD). Quantitative polymerase chain reaction (qPCR) and flow cytometry analyses were performed in subcutaneous (SAT), visceral (VAT), and perivascular adipose tissue (PVAT). Data of PAD patients showed significantly higher expression in VAT in all three genes (TNFα 5-fold, p<0.05; MCP-1 3.6-fold, p<0.05; IL-6 18.8-fold, p<0.001). The differences in PVAT and SAT were less significant. Total body pro-inflammatory status was documented by higher TNFα concentration in patients (4.86± 1.4 pg/ml) compared to LKDs (2.14±0.9 pg/ml; p<0.001), as was hsCRP (11.8±7.0 in PAD; 1.5±0.48 in LKDs; p=0.017). We found no age-dependent relationship between gene expression vs. TNFα and hsCRP concentrations in both compared groups. No effect of the atherosclerosis score on gene expression and circulating inflammatory markers within the PAD group was observed. Our results suggest that the AT of PAD patients infiltrated with macrophages produces more cytokines involved in the development of inflammation and atherosclerosis., S. Čejková, I. Králová Lesná, J. Froněk, L. Janoušek, A. Králová, J. Ždychová, R. Poledne., and Obsahuje bibliografii
Akt kinase regulates numerous cell functions including glucose metabolism, cell growth, survival, protein synthesis, and control of local hemodynamics. mTOR is one of down-stream effectors of Akt involved in the initiation of protein translation. However, renal Akt signaling in Type 1 diabetes (DM) in vivo, in particular under the conditions reflecting differences in metabolic control, has received less attention. Renal cortical activity and expression of Akt and mTOR (kinase assay, western blotting) were determined in streptozotocin-diabetic rats (D) with different levels of glycemic control (blood glucose 22.0± 1.0, 13.4±1.5, 8.1±0.4 mmol/l, p<0.05 between the groups), achieved by varying insulin treatment (0,4 and 12 IU/day), and in control rats with (C4) or without (C) chronic insulin administration. Renal Akt activity was reduced in D rats without insulin treatment and severe hyperglycemia (D-0, -62 %, p<0.01 vs. C), partially restored in moderately hypergly cemic rats (D-4, -30 %, p<0.05 vs. C), and normalized in D rats with intensive insulin and tight metabolic control (D-12). Expression of active mTOR paralleled Akt activity in D-0 (-51 %, p<0.01 vs. C), but not in D-4 and D- 12 that demonstrated increases in active mTOR (+55 %, +80 % resp., p<0.05) as compared to C. Moreover, insulin activated renal Akt (+82 %, p<0.01), but not mTOR in C4. In conclusion, glycemic control and intensity of insulin treatment are important modulators of renal Akt and mTOR activity in diabetes. While Akt activity is reversible by tight metabolic control, combination of hyperglycemia and insulin treatment resulted in enhancement of mTOR activity. In addition to Akt, other signaling pathways likely contribute to regulation of renal mTOR activity in diabetes., J. Ždychová, J. Veselá, L. Kazdová, R. Komers., and Obsahuje bibliografii a bibliografické odkazy