| 1. |
- Berglund, Lisa, et al.
(författare)
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Nuclear Factor of Activated T Cells Regulates Osteopontin Expression in Arterial Smooth Muscle in Response to Diabetes-Induced Hyperglycemia
- 2010
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Ingår i: ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY. - Baltimore : Lippincott Williams & Wilkins. - 1079-5642. ; 30, s. 154-218
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Tidskriftsartikel (refereegranskat)abstract
- Objective-Hyperglycemia is a recognized risk factor for cardiovascular disease in diabetes. Recently, we reported that high glucose activates the Ca2+/calcineurin-dependent transcription factor nuclear factor of activated T cells (NFAT) in arteries ex vivo. Here, we sought to determine whether hyperglycemia activates NFAT in vivo and whether this leads to vascular complications. Methods and Results-An intraperitoneal glucose-tolerance test in mice increased NFATc3 nuclear accumulation in vascular smooth muscle. Streptozotocin-induced diabetes resulted in increased NFATc3 transcriptional activity in arteries of NFAT-luciferase transgenic mice. Two NFAT-responsive sequences in the osteopontin (OPN) promoter were identified. This proinflammatory cytokine has been shown to exacerbate atherosclerosis and restenosis. Activation of NFAT resulted in increased OPN mRNA and protein in native arteries. Glucose-induced OPN expression was prevented by the ectonucleotidase apyrase, suggesting a mechanism involving the release of extracellular nucleotides. The calcineurin inhibitor cyclosporin A or the novel NFAT blocker A-285222 prevented glucose-induced OPN expression. Furthermore, diabetes resulted in higher OPN expression, which was significantly decreased by in vivo treatment with A-285222 for 4 weeks or prevented in arteries from NFATc3(-/-) mice. Conclusions-These results identify a glucose-sensitive transcription pathway in vivo, revealing a novel molecular mechanism that may underlie vascular complications of diabetes.
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| 2. |
- Garcia-Vaz, Eliana, et al.
(författare)
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Inhibition of NFAT signaling restores microvascular endothelial function in diabetic mice
- 2020
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 69:3, s. 424-435
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Tidskriftsartikel (refereegranskat)abstract
- Central to the development of diabetic macro- and microvascular disease is endothelial dysfunction, which appears well before any clinical sign but, importantly, is potentially reversible. We previously demonstrated that hyperglycemia activates nuclear factor of activated T cells (NFAT) in conduit and medium-sized resistance arteries and that NFAT blockade abolishes diabetes-driven aggravation of atherosclerosis. In this study, we test whether NFAT plays a role in the development of endothelial dysfunction in diabetes. NFAT-dependent transcriptional activity was elevated in skin microvessels of diabetic Akita (Ins21/2) mice when compared with nondiabetic littermates. Treatment of diabetic mice with the NFAT blocker A-285222 reduced NFATc3 nuclear accumulation and NFAT-luciferase transcriptional activity in skin microvessels, resulting in improved microvascular function, as assessed by laser Doppler imaging and iontophoresis of acetylcholine and localized heating. This improvement was abolished by pretreatment with the nitric oxide (NO) synthase inhibitor L-NGnitro-L-arginine methyl ester, while iontophoresis of the NO donor sodium nitroprusside eliminated the observed differences. A-285222 treatment enhanced dermis endothelial NO synthase expression and plasma NO levels of diabetic mice. It also prevented induction of inflammatory cytokines interleukin-6 and osteopontin, lowered plasma endothelin-1 and blood pressure, and improved mouse survival without affecting blood glucose. In vivo inhibition of NFAT may represent a novel therapeutic modality to preserve endothelial function in diabetes.
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| 3. |
- Virta, J, et al.
(författare)
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Impact of metabolic substrate modification on myocardial efficiency in a rat model of obesity and diabetes
- 2022
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Ingår i: European Heart Journal, Supplement. - : Oxford University Press (OUP). - 1520-765X .- 0195-668X .- 1522-9645. ; 43:2, s. 3076-3076
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Konferensbidrag (refereegranskat)abstract
- BackgroundCongenic leptin receptor deficient rat generated by introgression of the Koletsky leptin receptor mutation into BioBreeding Diabetes Resistant rat (BBDR.lepr−/−) is a novel animal model combining obesity, systemic insulin resistance and diabetes. Systemic insulin resistance is associated with reduced myocardial glucose utilization, but its effect on myocardial external efficiency, i.e. the ability of the myocardium to convert energy into external stroke work, remains uncertain.PurposeTo characterize cardiac energy metabolism and function in BBDR.lepr−/− rats and to study the effect of dipeptidyl peptidase 4 (DPP-4) inhibitor linagliptin in this model.MethodsCardiac phenotype was evaluated in six-month-old male BBDR.lepr−/− rats (n=11) and age-matched male non-diabetic lean control littermates (BBDR.lepr+/− or BBDR.lepr+/+ rats, n=14). Of these, 7 BBDR.lepr−/− rats and 6 controls underwent cardiac ultrasound, 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT), and [11C]acetate PET in order to evaluate cardiac structure and function as well as glucose and oxidative metabolism. In the remaining rats, fatty acid metabolism was evaluated by [18F]fluorothia-6-heptadecanoic acid ([18F]FTHA) PET/CT. In the linagliptin intervention study, 25 BBDR.lepr−/− male rats were randomly divided into control group (n=11) that received regular chow diet and linagliptin group (n=14) that received linagliptin (10mg/kg/d) mixed in the chow diet for three months. After the intervention, the rats underwent cardiac ultrasound, [18F]FDG PET/CT, and [11C]acetate PET.ResultsCompared with controls, BBDR.lepr−/− rats showed increased left ventricle (LV) mass (∼40%, p>0.001) and higher systolic blood pressure (∼10%, p=0.02). However, fractional shortening and cardiac output were similar in both groups. Myocardial fractional uptake rate of glucose measured with [18F]FDG PET was significantly reduced (∼86%, p=0.004) (Fig. 1A, E), whereas myocardial fatty acid uptake measured by [18F]FTHA PET was not significantly increased (free fatty acid (FFA) corrected standardized uptake value (SUV) ∼21%, p=0.54) (Fig. 1B) in BBDR.lepr−/− compared to controls. Myocardial oxygen consumption assessed by [11C]acetate PET was similar in both groups (Fig. 1C, E), but LV work per gram of myocardium was reduced (∼28%, p=0.001) resulting in reduced myocardial external efficiency (∼21%, p=0.03) (Fig. 1D) in BBDR.lepr−/− compared to controls. Treatment with linagliptin significantly enhanced myocardial fractional uptake rate of glucose (∼166%, p=0.006) (Fig. 2A, C), but had no effect on efficiency of cardiac work (Fig. 2B).ConclusionsObese and diabetic BBDR.lepr−/− rats demonstrate LV hypertrophy and markedly reduced myocardial glucose utilization associated with impaired myocardial external efficiency despite normal LV systolic function. Enhancement of myocardial glucose uptake by linagliptin did not improve efficiency of cardiac work.Funding AcknowledgementType of funding sources: Public grant(s) – EU funding. Main funding source(s): IMI-SUMMIT
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| 4. |
- Parzych, Katarzyna, et al.
(författare)
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Differential role of pannexin-1/ATP/P2X7 axis in IL-1β release by human monocytes
- 2017
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Ingår i: FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 31:6, s. 2439-2445
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Tidskriftsartikel (refereegranskat)abstract
- IL-1β release is integral to the innateimmunesystem.The release ofmature IL-1βdepends on 2 regulated events: the de novo induction of pro-IL-1β, generally via NF-κB-dependent transduction pathways; and the assembly and activation of the NLRP3 inflammasome. This latter step is reliant on active caspase-1, pannexin-1, and P2X7 receptor activation. Pathogen-associated molecular patterns in gram-positive and gram-negative bacteria activate IL-1β release from immune cells via TLR2 and TLR4 receptors, respectively. We found that pro-IL-1β and mature IL-1β release fromhumanmonocytes is stimulated by the TLR2 agonists Pam3CSK4 or FSL-1, as well as the TLR4agonist LPSin the absence of additionalATP.TLR2agonists requiredpannexin-1 and P2X7 receptor activation to stimulate IL-1β release. In contrast, IL-1β release stimulated by the TLR4 agonist LPS is independent of both pannexin-1 and P2X7 activation. In the absenceof exogenousATP,P2X7 activationrequires endogenousATPrelease, which occurs in some cells via pannexin-1. In line with this, we found that LPS-stimulated human monocytes released relatively low levels of ATP, whereas cells stimulated with TLR2 agonists released high levels of ATP. These findings suggest that in humanmonocytes, both TLR2 and TLR4 signaling induce pro-IL-1β expression, but themechanismbywhich they activate caspase-1diverges at the level of thepannexin-1/ATP/P2X7 axis.
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| 5. |
- Zetterqvist, Anna, et al.
(författare)
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Nuclear Factor of Activated T Cells Is Activated in the Endothelium of Retinal Microvessels in Diabetic Mice.
- 2015
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Ingår i: Journal of Diabetes Research. - : Hindawi Limited. - 2314-6753 .- 2314-6745. ; 2015
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Tidskriftsartikel (refereegranskat)abstract
- The pathogenesis of diabetic retinopathy (DR) remains unclear but hyperglycemia is an established risk factor. Endothelial dysfunction and changes in Ca(2+) signaling have been shown to precede the onset of DR. We recently demonstrated that high extracellular glucose activates the Ca(2+)/calcineurin-dependent transcription factor NFAT in cerebral arteries and aorta, promoting the expression of inflammatory markers. Here we show, using confocal immunofluorescence, that NFAT is expressed in the endothelium of retinal microvessels and is readily activated by high glucose. This was inhibited by the NFAT blocker A-285222 as well as by the ectonucleotidase apyrase, suggesting a mechanism involving the release of extracellular nucleotides. Acute hyperglycemia induced by an IP-GTT (intraperitoneal glucose tolerance test) resulted in increased NFATc3 nuclear accumulation and NFAT-dependent transcriptional activity in retinal vessels of NFAT-luciferase reporter mice. In both Akita (Ins2(+/-) ) and streptozotocin- (STZ-) induced diabetic mice, NFAT transcriptional activity was elevated in retinal vessels. In vivo inhibition of NFAT with A-285222 decreased the expression of OPN and ICAM-1 mRNA in retinal vessels, prevented a diabetes driven downregulation of anti-inflammatory IL-10 in retina, and abrogated the increased vascular permeability observed in diabetic mice. Results identify NFAT signaling as a putative target for treatment of microvascular complications in diabetes.
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