Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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IL-37 expression reduces lean body mass in mice by reducing food intake
Kuipers, Eline N. ; Dam, Andrea D. van; Ballak, Dov B. ; Wit, Ellemiek A. de; Dinarello, Charles A. ; Stienstra, Rinke ; Diepen, Janna A. van; Rensen, Patrick C.N. ; Boon, Mariëtte R. - \ 2018
International Journal of Molecular Sciences 19 (2018)8. - ISSN 1661-6596
Energy metabolism - Food intake - High fat diet - IL-37

The human cytokine interleukin (IL)-37 is an anti-inflammatory member of the IL-1 family of cytokines. Transgenic expression of IL-37 in mice protects them from diet-induced obesity and associated metabolic complications including dyslipidemia, inflammation and insulin resistance. The precise mechanism of action leading to these beneficial metabolic effects is not entirely known. Therefore, we aimed to assess in detail the effect of transgenic IL-37 expression on energy balance, including food intake and energy expenditure. Feeding homozygous IL-37 transgenic mice and wild-type (WT) control mice a high-fat diet (HFD; 45% kcal palm fat) for 6 weeks showed that IL-37 reduced body weight related to a marked decrease in food intake. Subsequent mechanistic studies in mice with heterozygous IL-37 expression versus WT littermates, fed the HFD for 18 weeks, confirmed that IL-37 reduces food intake, which led to a decrease in lean body mass, but did not reduce fat mass and plasma lipid levels or alterations in energy expenditure independent of lean body mass. Taken together, this suggests that IL-37 reduces lean body mass by reducing food intake.

A Diurnal Rhythm in Brown Adipose Tissue Causes Rapid Clearance and Combustion of Plasma Lipids at Wakening
Berg, Rosa van den; Kooijman, Sander ; Noordam, Raymond ; Ramkisoensing, Ashna ; Abreu-Vieira, Gustavo ; Tambyrajah, Lauren L. ; Dijk, Wieneke ; Ruppert, Philip ; Mol, Isabel M. ; Kramar, Barbara ; Caputo, Rosanna ; Puig, Laura Sardón ; Ruiter, Evelien M. de; Kroon, Jan ; Hoekstra, Menno ; Sluis, Ronald J. van der; Meijer, Onno C. ; Willems van Dijk, Ko ; Kerkhof, Linda W.M. van; Christodoulides, Constantinos ; Karpe, Fredrik ; Gerhart-Hines, Zachary ; Kersten, Sander ; Meijer, Johanna H. ; Coomans, Claudia P. ; Heemst, Diana van; Biermasz, Nienke R. ; Rensen, Patrick C.N. - \ 2018
Cell Reports 22 (2018)13. - ISSN 2211-1247 - p. 3521 - 3533.
angiopoietin-like 4 - APOE3-Leiden.CETP mice - brown adipose tissue - circadian rhythm - diurnal rhythm - fatty acids - lipoprotein lipase - postprandial lipid response - triglycerides
Many favorable metabolic effects have been attributed to thermogenic activity of brown adipose tissue (BAT). Yet, time of day has rarely been considered in this field of research. Here, we show that a diurnal rhythm in BAT activity regulates plasma lipid metabolism. We observed a high-amplitude rhythm in fatty acid uptake by BAT that synchronized with the light/dark cycle. Highest uptake was found at the onset of the active period, which coincided with high lipoprotein lipase expression and low angiopoietin-like 4 expression by BAT. Diurnal rhythmicity in BAT activity determined the rate at which lipids were cleared from the circulation, thereby imposing the daily rhythm in plasma lipid concentrations. In mice as well as humans, postprandial lipid excursions were nearly absent at waking. We anticipate that diurnal BAT activity is an important factor to consider when studying the therapeutic potential of promoting BAT activity. van den Berg et al. show a strong circadian rhythm in fatty acid uptake by brown adipose tissue that peaks at wakening regardless of the light exposure period. Consequently, postprandial lipid handling by brown adipose tissue is highest at wakening, resulting in the lowest postprandial plasma lipid excursions.
Metabolic imaging of fatty kidney in diabesity : Validation and dietary intervention
Jonker, Jacqueline T. ; Heer, Paul De; Engelse, Marten A. ; Rossenberg, Evelien H. Van; Klessens, Celine Q.F. ; Baelde, Hans J. ; Bajema, Ingeborg M. ; Koopmans, Sietse Jan ; Coelho, Paulo G. ; Streefland, Trea C.M. ; Webb, Andrew G. ; Dekkers, Ilona A. ; Rabelink, Ton J. ; Rensen, Patrick C.N. ; Lamb, Hildo J. ; Vries, Aiko P.J. De - \ 2018
Nephrology Dialysis Transplantation 33 (2018)2. - ISSN 0931-0509 - p. 224 - 230.
chronic kidney disease - fatty kidney - proton magnetic - renal triglyceride content - resonance spectroscopy - type 2 diabetes mellitus
Background Obesity and type 2 diabetes have not only been linked to fatty liver, but also to fatty kidney and chronic kidney disease. Since non-invasive tools are lacking to study fatty kidney in clinical studies, we explored agreement between proton magnetic resonance spectroscopy (1 H-MRS) and enzymatic assessment of renal triglyceride content (without and with dietary intervention). We further studied the correlation between fatty kidney and fatty liver. Methods Triglyceride content in the renal cortex was measured by 1 H-MRS on a 7-Tesla scanner in 27 pigs, among which 15 minipigs had been randomized to a 7-month control diet, cafeteria diet (CAF) or CAF with low-dose streptozocin (CAF-S) to induce insulin-independent diabetes. Renal biopsies were taken from corresponding MRS-voxel locations. Additionally, liver biopsies were taken and triglyceride content in all biopsies was measured by enzymatic assay. Results Renal triglyceride content measured by 1 H-MRS and enzymatic assay correlated positively (r = 0.86, P < 0.0001). Compared with control diet-fed minipigs, renal triglyceride content was higher in CAF-S-fed minipigs (137 ± 51 nmol/mg protein, mean ± standard error of the mean, P < 0.05), but not in CAF-fed minipigs (60 ± 10 nmol/mg protein) compared with controls (40 ± 6 nmol/mg protein). Triglyceride contents in liver and kidney biopsies were strongly correlated (r = 0.97, P < 0.001). Conclusions Non-invasive measurement of renal triglyceride content by 1 H-MRS closely predicts triglyceride content as measured enzymatically in biopsies, and fatty kidney appears to develop parallel to fatty liver. 1 H-MRS may be a valuable tool to explore the role of fatty kidney in obesity and type 2 diabetic nephropathy in humans in vivo.
Short-term cooling increases serum angiopoietin-like 4 levels in healthy lean men
Nahon, Kimberly J. ; Hoeke, Geerte ; Bakker, Leontine E.H. ; Jazet, Ingrid M. ; Berbée, Jimmy F.P. ; Kersten, Sander ; Rensen, Patrick C.N. ; Boon, Mariëtte R. - \ 2018
Journal of Clinical Lipidology 12 (2018)1. - ISSN 1933-2874 - p. 56 - 61.
Angiopoietin-like 4 - Brown adipose tissue - Cold exposure - South Asians - Sympathetic nervous system
Background: Cold exposure enhances sympathetic outflow to peripheral tissues, thereby stimulating intracellular lipolysis in white adipose tissue and increasing the lipoprotein lipase-dependent uptake and combustion of triglyceride-derived fatty acids (FAs) by brown adipose tissue. Angiopoietin-like 4 (ANGPTL4) inhibits lipoprotein lipase and can be regulated by cold exposure, at least in mice. Objective: In the present study, we examined the effect of short-term mild cooling on serum ANGPTL4 levels in healthy lean men of White Caucasian and South Asian descent. Methods: Healthy, lean White Caucasian (n = 12) and South Asian (n = 12) men were exposed to an individualized cooling protocol for 2 hours. Serum ANGPTL4 levels were measured before and after cooling, and its relation with previously measured parameters (ie, free fatty acid [FFA] levels, body fat percentage, and resting energy expenditure) was determined. Results: Short-term cooling increased ANGPTL4 levels (+17%, P < .001). Thermoneutral ANGPTL4 levels positively correlated with FFA levels (R 2 = 0.250, P < .05) and body fat percentage (R 2 = 0.338, P < .05). Furthermore, ANGPTL4 negatively correlated with resting energy expenditure (R 2 = 0.235, P < .05). The relative increase in ANGPTL4 levels was higher in White Caucasians compared with South Asians (25 ± 4 vs 9 ± 4%, P < .05). Conclusion: Short-term cooling increases ANGPTL4 levels in healthy lean men. We anticipate that FFA liberated from white adipose tissue during cooling increases ANGPTL4 to limit uptake of triglyceride-derived FA by this tissue.
The effects of selective hematopoietic expression of human IL-37 on systemic inflammation and atherosclerosis in LDLr-deficient mice
Hoeke, Geerte ; Khedoe, P.P.S.J. ; Diepen, Janna A. Van; Pike-Overzet, Karin ; Ven, Britt van de; Vazirpanah, Nadia ; Mol, Isabel ; Hiemstra, Pieter S. ; Staal, Frank J.T. ; Stienstra, Rinke ; Netea, Mihai G. ; Dinarello, Charles A. ; Rensen, Patrick C.N. ; Berbée, Jimmy F.P. - \ 2017
International Journal of Molecular Sciences 18 (2017)8. - ISSN 1661-6596
Atherosclerosis - Hyperlipidemia - Inflammation - Interleukin-37

The human cytokine interleukin (IL)-37 has potent anti-inflammatory capacities, and hematopoietic cell-specific transgenic overexpression of IL-37 in mice protects against septic shock and colitis. In the present study we investigated the effect of hematopoietic expression of IL-37 on atherosclerosis development under low-grade inflammatory conditions. Low-density lipoprotein receptor (LDLr)-deficient mice were lethally irradiated and transplanted with bone marrow from IL-37-transgenic or control wild-type mice and fed a Western-type diet (WTD; 1% cholesterol) for eight weeks. Metabolic and inflammatory parameters were monitored and atherosclerosis was assessed in the aortic valve area. Hematopoietic IL-37 expression did not influence body weight, food intake and plasma cholesterol levels during the study. Plasma soluble E-selectin levels were increased with WTD-feeding as compared to chow-feeding, but were not influenced by IL-37 expression. IL-37 expression reduced the inflammatory state as indicated by reduced white blood cell counts and by reduced basal and lipopolysaccharide-induced cytokine response by peritoneal macrophages ex vivo. IL-37 expression did not influence the atherosclerotic lesion area. Lesion composition was marginally affected. Smooth muscle cell content was decreased, but macrophage and collagen content were not different. We conclude that under low-grade inflammatory conditions, hematopoietic IL-37 expression reduces the inflammatory state, but does not influence atherosclerosis development in hyperlipidemic LDLr-deficient mice.

ANGPTL4 mediates shuttling of lipid fuel to brown adipose tissue during sustained cold exposure
Dijk, Wieneke ; Heine, Markus ; Vergnes, Laurent ; Boon, Mariëtte R. ; Schaart, Gert ; Hesselink, Matthijs K.C. ; Reue, Karen ; Marken Lichtenbelt, Wouter D. van; Olivecrona, Gunilla ; Rensen, Patrick C.N. ; Heeren, Joerg ; Kersten, Sander - \ 2015
eLife 4 (2015). - ISSN 2050-084X - 23 p.

Brown adipose tissue (BAT) activation via cold exposure is increasingly scrutinized as a potential approach to ameliorate cardio-metabolic risk. Transition to cold temperatures requires changes in the partitioning of energy substrates, re-routing fatty acids to BAT to fuel non-shivering thermogenesis. However, the mechanisms behind the redistribution of energy substrates to BAT remain largely unknown. Angiopoietin-like 4 (ANGPTL4), a protein that inhibits lipoprotein lipase (LPL) activity, is highly expressed in BAT. Here, we demonstrate that ANGPTL4 is part of a shuttling mechanism that directs fatty acids derived from circulating triglyceride-rich lipoproteins to BAT during cold. Specifically, we show that cold markedly down-regulates ANGPTL4 in BAT, likely via activation of AMPK, enhancing LPL activity and uptake of plasma triglyceride-derived fatty acids. In contrast, cold up-regulates ANGPTL4 in WAT, abolishing a cold-induced increase in LPL activity. Together, our data indicate that ANGPTL4 is an important regulator of plasma lipid partitioning during sustained cold.

Brown adipose tissue takes up plasma triglycerides mostly after lipolysis
Khedoe, P.P.S.J. ; Hoeke, Geerte ; Kooijman, Sander ; Dijk, Wieneke ; Buijs, Jeroen T. ; Kersten, Sander ; Havekes, Louis M. ; Hiemstra, Pieter S. ; Berbée, Jimmy F.P. ; Boon, Mariëtte R. ; Rensen, Patrick C.N. - \ 2015
Journal of Lipid Research 56 (2015)1. - ISSN 0022-2275 - p. 51 - 59.
Cholesterol - Chylomicrons - Fatty acid metabolism - Lipids - Lipoprotein lipase - Lipoproteins/metabolism

Brown adipose tissue (BAT) produces heat by burning TGs that are stored within intracellular lipid droplets and need to be replenished by the uptake of TG-derived FA from plasma. It is currently unclear whether BAT takes up FA via uptake of TG-rich lipoproteins (TRLs), after lipolysis-mediated liberation of FA, or via a combination of both. Therefore, we generated glycerol tri[3H]oleate and [14C]cholesteryl oleate double-labeled TRL-mimicking particles with an average diameter of 45, 80, and 150 nm (representing small VLDL to chylomicrons) and injected these intravenously into male C57Bl/6J mice. At room temperature (21°C), the uptake of 3H-activity by BAT, expressed per gram of tissue, was much higher than the uptake of 14C-activity, irrespective of particle size, indicating lipolysis-mediated uptake of TG-derived FA rather than whole particle uptake. Cold exposure (7°C) increased the uptake of FA derived from the differently sized particles by BAT, while retaining the selectivity for uptake of FA over cholesteryl ester (CE). At thermoneutrality (28°C), total FA uptake by BAT was attenuated, but the specificity of uptake of FA over CE was again largely retained. Altogether, we conclude that, in our model, BAT takes up plasma TG preferentially by means of lipolysis-mediated uptake of FA.

Navigating through metaproteomics data : A logbook of database searching
Muth, Thilo ; Kolmeder, C.A. ; Salojärvi, Jarkko ; Keskitalo, Salla ; Varjosalo, Markku ; Verdam, F.J. ; Rensen, S.S. ; Reichl, Udo ; Vos, W.M. de; Rapp, Erdmann ; Martens, Lennart - \ 2015
Proteomics 15 (2015)20. - ISSN 1615-9853 - p. 3439 - 3453.
Bioinformatics - De novo sequencing - False discovery rate - Metaproteomics - Search parameters

Metaproteomic research involves various computational challenges during the identification of fragmentation spectra acquired from the proteome of a complex microbiome. These issues are manifold and range from the construction of customized sequence databases, the optimal setting of search parameters to limitations in the identification search algorithms themselves. In order to assess the importance of these individual factors, we studied the effect of strategies to combine different search algorithms, explored the influence of chosen database search settings, and investigated the impact of the size of the protein sequence database used for identification. Furthermore, we applied de novo sequencing as a complementary approach to classic database searching. All evaluations were performed on a human intestinal metaproteome dataset. Pyrococcus furiosus proteome data were used to contrast database searching of metaproteomic data to a classic proteomic experiment. Searching against subsets of metaproteome databases and the use of multiple search engines increased the number of identifications. The integration of P. furiosus sequences in a metaproteomic sequence database showcased the limitation of the target-decoy-controlled false discovery rate approach in combination with large sequence databases. The selection of varying search engine parameters and the application of de novo sequencing represented useful methods to increase the reliability of the results. Based on our findings, we provide recommendations for the data analysis that help researchers to establish or improve analysis workflows in metaproteomics.

Caspase-1 deficiency reduces intestinal and hepatic triglyceride-rich lipoprotein secretion
Diepen, Janna A. van; Stienstra, Rinke ; Hooiveld, Guido ; Willems van Dijk, Ko ; Rensen, Patrick C. - \ 2013
Mus musculus - GSE32515 - PRJNA147849
Background and Aims: Inflammasome-mediated caspase-1 activity regulates the maturation and release of the pro-inflammatory cytokines interleukin (IL)-1ß and IL-18. Recently, we showed that caspase-1 deficiency strongly reduces high fat diet-induced adiposity although the mechanism is still unclear. We now aimed to elucidate the mechanism by which caspase-1 deficiency reduces modulates resistance to high fat diet-feeding fat accumulation in adipose tissue by focusing on the role of caspase-1 in the regulation of triglyceride (TG)-rich lipoprotein metabolism. Methods: Caspase-1 deficient and wild-type mice (both C57Bl/6 background) were used to determine postprandial TG kinetics, intestinal TG absorption, VLDL-TG production as well as TG clearance, all of which strongly contribute to the supply of TG for storage in adipose tissue. Micro-array and qPCR analysis were used to unravel intestinal and hepatic metabolic pathways involved. Results: Caspase-1 deficiency reduced the postprandial response to an oral lipid load, while tissue specific clearance of TG-rich lipoproteins was not changed. Indeed, an oral olive oil gavage containing [3H]TG revealed that caspase-1 deficiency significantly decreased intestinal chylomicron-TG production and reduced the uptake of [3H]TG-derived FA by liver, muscle, and adipose tissue. Similarly, caspase-1 deficiency reduced the hepatic VLDL-TG production without reducing VLDL-apoB production, despite an elevated hepatic TG content. Pathway analysis revealed that caspase-1 deficiency reduces intestinal and hepatic expression of genes involved in lipogenesis. Conclusions: Absence of caspase-1 reduces assembly and secretion of TG-rich lipoproteins, thereby reducing the availability of TG-derived FA for uptake by peripheral organs including adipose tissue. We anticipate that caspase-1 represents a novel link between innate immunity and lipid metabolism.
Dietary modulation of plasma angiopoietin-like protein 4 concentrations in healthy volunteers and in patients with type 2 diabetes
Jonker, J.T. ; Smit, J.W.A. ; Hammer, S. ; Snel, M. ; Meer, R. van der; Lamb, H.J. ; Mattijssen, F.B.J. ; Mudde, C.M. ; Jazet, I.M. ; Dekkers, O.M. ; Roos, A. de; Romijn, J.A. ; Kersten, A.H. ; Rensen, P.C.N. - \ 2013
American Journal of Clinical Nutrition 97 (2013)2. - ISSN 0002-9165 - p. 255 - 260.
myocardial triglyceride content - free fatty-acids - lipoprotein-lipase - caloric restriction - diastolic function - angptl4 - mice - hyperlipidemia - inhibition - humans
Background: Angiopoietin-like protein 4 (ANGPTL4) has been identified as an inhibitor of lipoprotein lipase. Preliminary data suggest that plasma nonesterified fatty acids (NEFAs) raise plasma ANGPTL4 concentrations in humans. Objective: The objective was to assess plasma ANGPTL4 concentrations after various nutritional interventions that increase NEFA concentrations in healthy subjects and in patients with type 2 diabetes mellitus. Design: We studied 4 groups, both at baseline and after 3 d of either fasting (n = 22 healthy men), a very-low-calorie diet (VLCD; n = 10 healthy men and n = 10 patients with diabetes), or a high-fat, high-energy diet (HFED; n = 15 healthy men). Plasma ANGPTL4, NEFA, and triglyceride concentrations were measured. Results: In healthy men, a VLCD increased ANGPTL4 from 13.2 (IQR: 8.1-24.2) at baseline to 18.2 (16.7-33.4) ng/mL (P <0.05), fasting increased ANGPTL4 from 10.6 (7.6-17.6) to 28.0 (23.1-35.0) ng/mL (P <0.05), and an HFED increased ANGPTL4 from 13.9 (8.2-22.0) to 17.2 (11.2-23.6) ng/mL (P <0.05). In men with diabetes, a VLCD also increased ANGPTL4, from 10.9 +/- 2.4 to 19.2 +/- 3.2 ng/mL (P <0.05). All interventions significantly increased plasma NEFAs in both healthy men and patients with diabetes. The change in ANGPTL4 positively correlated with the change in NEFA concentrations (beta = 0.048, P <0.001) and negatively correlated with the change in plasma triglycerides (beta = -0.051, P = 0.01). Conclusions: Three days of either fasting, a VLCD, or an HFED increased plasma ANGPTL4 concentrations in healthy men, concomitantly with increased plasma NEFA concentrations. Similarly, a VLCD in patients with diabetes increased ANGPTL4 concentrations, concomitantly with increased NEFA concentrations. Am J Clin Nutr 2013;97:255-60.
Caspase-1 deficiency in mice reduces intestinal triglyceride absorption and hepatic triglyceride secretion
Diepen, J.A. van; Stienstra, R. ; Vroegrijk, I.O.C.M. ; Berg, S.A.A. van den; Salvatori, D. ; Hooiveld, G.J.E.J. ; Kersten, A.H. ; Tack, C.J. ; Netea, M.G. ; Smit, J.W.A. ; Joosten, L.A.B. ; Havekes, L.M. ; Dijk, K.W. van; Rensen, P.C.N. - \ 2013
Journal of Lipid Research 54 (2013)2. - ISSN 0022-2275 - p. 448 - 456.
lipid-metabolism - adipose-tissue - fatty-acids - lipoprotein metabolism - insulin-resistance - immune-responses - inflammation - liver - inflammasomes - interleukin-1
Caspase-1 is known to activate the proinflammatory cytokines IL-1 beta and IL-18. Additionally, it can cleave other substrates, including proteins involved in metabolism. Recently, we showed that caspase-1 deficiency in mice strongly reduces high-fat diet-induced weight gain, at least partly caused by an increased energy production. Increased feces secretion by caspase-1-deficient mice suggests that lipid malabsorption possibly further reduces adipose tissue mass. In this study we investigated whether caspase-1 plays a role in triglyceride-(TG)-rich lipoprotein metabolism using caspase-1-deficient and wild-type mice. Caspase-1 deficiency reduced the postprandial TG response to an oral lipid load, whereas TG-derived fatty acid (FA) uptake by peripheral tissues was not affected, demonstrated by unaltered kinetics of [H-3] TG-labeled very low-density lipoprotein (VLDL)-like emulsion particles. An oral gavage of [H-3] TG-containing olive oil revealed that caspase-1 deficiency reduced TG absorption and subsequent uptake of TG-derived FA in liver, muscle, and adipose tissue. Similarly, despite an elevated hepatic TG content, caspase-1 deficiency reduced hepatic VLDL-TG production. Intestinal and hepatic gene expression analysis revealed that caspase-1 deficiency did not affect FA oxidation or FA uptake but rather reduced intracellular FA transport, thereby limiting lipid availability for the assembly and secretion of TG-rich lipoproteins.(jlr) The current study reveals a novel function for caspase-1, or caspase-1-cleaved substrates, in controlling intestinal TG absorption and hepatic TG secretion.-van Diepen, J. A., R. Stienstra, I. O. C. M. Vroegrijk, S. A. A. van den Berg, D. Salvatori, G. J. Hooiveld, S. Kersten, C. J. Tack, M. G. Netea, J. W. A. Smit, L. A. B. Joosten, L. M. Havekes, K. W. van Dijk, and P. C. N. Rensen. Caspase-1 deficiency in mice reduces intestinal triglyceride absorption and hepatic triglyceride secretion. J. Lipid Res. 2013. 54: 448-456.
Overexpression of angiopoietin-like protein 4 protects against atherosclerosis development
Georgiadi, A. ; Wang, Y. ; Stienstra, R. ; Tjeerdema, N. ; Janssen, A. ; Stalenhoef, A. ; Vliet, A. van der; Roos, J.A. de; Tamsma, J.T. ; Smit, J.W. ; Tan, N.S. ; Müller, M.R. ; Rensen, P.C. ; Kersten, A.H. - \ 2013
Arteriosclerosis Thrombosis and Vascular Biology 33 (2013)7. - ISSN 1079-5642 - p. 1529 - 1537.
low-density-lipoprotein - mouse peritoneal-macrophages - foam cell-formation - transgenic mice - lipase - angptl4 - expression - gene - hyperlipoproteinemia - hyperlipidemia
Objective—Macrophage foam cells play a crucial role in several pathologies including multiple sclerosis, glomerulosclerosis, and atherosclerosis. Angiopoietin-like protein 4 (Angptl4) was previously shown to inhibit chyle-induced foam cell formation in mesenteric lymph nodes. Here we characterized the regulation of Angptl4 expression in macrophages and examined the impact of Angptl4 on atherosclerosis development. Approach and Results—Macrophage activation elicited by pathogen-recognition receptor agonists decreased Angptl4 expression, whereas lipid loading by intralipid and oxidized low-density lipoprotein increased Angptl4 expression. Consistent with an antilipotoxic role of Angptl4, recombinant Angptl4 significantly decreased uptake of oxidized low-density lipoprotein by macrophages, via lipolysis-dependent and -independent mechanisms. Angptl4 protein was detectable in human atherosclerotic lesions and localized to macrophages. Transgenic overexpression of Angptl4 in atherosclerosis-prone apolipoprotein E*3-Leiden mice did not significantly alter plasma cholesterol and triglyceride levels. Nevertheless, Angptl4 overexpression reduced lesion area by 34% (P
Human intestinal microbiota composition is associated with local and systemic inflammation in obesity
Verdam, F.J. ; Fuentes Enriquez de Salamanca, S. ; Jonge, C. de; Zoetendal, E.G. ; Erbil, R. ; Greve, J.W. ; Buurman, W.A. ; Vos, W.M. de; Rensen, S.S. - \ 2013
Obesity 21 (2013)12. - ISSN 1930-7381 - p. E607 - E615.
human gut microbiota - diet-induced obesity - high-fat diet - fecal calprotectin - nonalcoholic steatohepatitis - weight-loss - bowel - mice - permeability - disease
OBJECTIVE: Intestinal microbiota have been suggested to contribute to the development of obesity, but the mechanism remains elusive. The relationship between microbiota composition, intestinal permeability, and inflammation in nonobese and obese subjects was investigated. DESIGN AND METHODS: Fecal microbiota composition of 28 subjects (BMI 18.6-60.3 kg m-2 ) was analyzed by a phylogenetic profiling microarray. Fecal calprotectin and plasma C-reactive protein levels were determined to evaluate intestinal and systemic inflammation. Furthermore, HbA1c , and plasma levels of transaminases and lipids were analyzed. Gastroduodenal, small intestinal, and colonic permeability were assessed by a multisaccharide test. RESULTS: Based on microbiota composition, the study population segregated into two clusters with predominantly obese (15/19) or exclusively nonobese (9/9) subjects. Whereas intestinal permeability did not differ between clusters, the obese cluster showed reduced bacterial diversity, a decreased Bacteroidetes/Firmicutes ratio, and an increased abundance of potential proinflammatory Proteobacteria. Interestingly, fecal calprotectin was only detectable in subjects within the obese microbiota cluster (n = 8/19, P = 0.02). Plasma C-reactive protein was also increased in these subjects (P = 0.0005), and correlated with the Bacteroidetes/Firmicutes ratio (rs = -0.41, P = 0.03). CONCLUSIONS: Intestinal microbiota alterations in obese subjects are associated with local and systemic inflammation, suggesting that the obesity-related microbiota composition has a proinflammatory effect
Zoutverlaging vleeswaren kan alleen in stappen
Rensen, E. ; Janssen, A.M. - \ 2012
Vlees Magazine (Industriespecial) 2012 (2012)December. - ISSN 2214-1170 - p. 32 - 34.
Regulation of Photosystem II Electron transport by Bicarbonate
Rensen, J.J.S. van - \ 2012
In: Photosynthesis: Plastid Biology, Energy Conversion and Carbon Assimilation, Advances in Photosynthesis and Respiration / Eaton-Rye, J.J., Tripathy, B.C., Sharkey, T.D., - p. 475 - 500.
In oxygenic photosynthesis, carbon dioxide is fixed by ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) and further reduced to carbohydrates. However, CO2, in the form of carbonate or bicarbonate, is also directly involved in the “light reactions” through structural and regulatory roles within Photosystem II (PS II). A notable feature is antagonistic interactions between bicarbonate (carbonate) and monovalent anions such as formate within PS II. Incubation of PS II-containing samples with formate results in the inhibition of electron flow activity, which can be restored only by the addition of bicarbonate. This “bicarbonate effect” influences molecular processes associated with both the electron acceptor and electron donor sides of PS II. The bicarbonate interaction on the acceptor side is located in the region of the primary and secondary quinones and contributes to the protonation states associated with quinol formation. At physiological pH, bicarbonate (carbonate) is a ligand to the non-heme iron and forms hydrogen bonds to several amino acids of the D1 and D2 proteins. Bicarbonate may stabilize, through conformational means, the reaction center proteins by protonation of certain amino acids near the secondary quinone electron acceptor. A possible functional role in vivo is that it controls PS II electron flow in order to ameliorate the impact of stress conditions leading to, for instance, photoinhibition or thermoinactivation. The role of bicarbonate on the donor of PS II has been the subject of renewed interest and bicarbonate has been suggested to play a role in the assembly of the Mn4Ca cluster during photoactivation. Additionally, a role as a catalytic base or proton transporter on the donor side of PS II has been proposed. However, while clear evidence for bicarbonate’s role on the acceptor side has been established, experiments designed to elucidate the putative role of bicarbonate on the donor side of PS II have not yet provided convincing evidence.
The inflammasome is a central player in the induction of obesity and insulin resistance
Stienstra, Rinke ; Diepen, Janna A. van; Tack, Cees J. ; Zaki, Mohammad H. ; Veerdonk, Frank L. van de; Perera, Deshani ; Neal, Geoff ; Hijmans, Anneke ; Vroegrijk, Irene O. ; Berg, Sjoerd A. van den; Romijn, Johannes A. ; Rensen, Patrick C. ; Joosten, Leo A. ; Netea, Mihai G. ; Kanneganti, Thirumala-Devi D. - \ 2011
GSE25205 - Mus musculus - PRJNA134319
Inflammation plays a key role in the pathogenesis of obesity. Chronic overfeeding leads to macrophage infiltration in the adipose tissue, resulting in pro-inflammatory cytokine production. Both microbial and endogenous danger signals trigger assembly of the intracellular innate immune sensor Nlrp3 [NLR family, pyrin domain containing 3] resulting in caspase-1 activation and production of pro-inflammatory cytokines interleukin (IL)-1beta and IL-18. Here, we showed that mice deficient in Nlrp3, ASC [apoptosis-associated speck-like protein containing a CARD; a.k.a PYCARD (PYD and CARD domain containing)] and caspase-1 were resistant to the development of high fat diet-induced obesity, which correlated with protection from obesity-induced insulin resistance. Detailed metabolic and molecular phenotyping demonstrated that the inflammasome controls energy expenditure and adipogenic gene expression during chronic overfeeding. These findings reveal a critical function of the inflammasome in obesity and insulin resistance and suggest inhibition of the inflammasome as a potential therapeutic strategy.
Inflammasome is a central player in the induction of obesity and insulin resistance
Stienstra, R. ; Diepen, J.A. van; Tack, C.J. ; Zaki, M.H. ; Veerdonk, F.L. van de; Perera, D. ; Neale, G.A. ; Hooiveld, G.J.E.J. ; Hijmans, A. ; Vroegrijk, I. ; Berg, S. ; Romijn, J. ; Rensen, P.C.N. ; Joosten, L.A.B. ; Netea, M.G. ; Kanneganti, T.D. - \ 2011
Proceedings of the National Academy of Sciences of the United States of America 108 (2011)37. - ISSN 0027-8424 - p. 15324 - 15329.
adipose-tissue - mice deficient - caspase-1 - interleukin-18 - expression - sensitivity - activation - il-1-beta - apoptosis - crystals
Inflammation plays a key role in the pathogenesis of obesity. Chronic overfeeding leads to macrophage infiltration in the adipose tissue, resulting in proinflammatory cytokine production. Both microbial and endogenous danger signals trigger assembly of the intracellular innate immune sensor Nlrp3, resulting in caspase-1 activation and production of proinflammatory cytokines IL-1 beta and IL-18. Here, we showed that mice deficient in Nlrp3, apoptosis-associated speck-like protein, and caspase-1 were resistant to the development of high-fat diet-induced obesity, which correlated with protection from obesity-induced insulin resistance. Furthermore, hepatic triglyceride content, adipocyte size, and macrophage infiltration in adipose tissue were all reduced in mice deficient in inflammasome components. Monocyte chemoattractant protein (MCP)-1 is a key molecule that mediates macrophage infiltration. Indeed, defective inflammasome activation was associated with reduced MCP-1 production in adipose tissue. Furthermore, plasma leptin and resistin that affect energy use and insulin sensitivity were also changed by inflammasome-deficiency. Detailed metabolic and molecular phenotyping demonstrated that the inflammasome controls energy expenditure and adipogenic gene expression during chronic overfeeding. These findings reveal a critical function of the inflammasome in obesity and insulin resistance, and suggest inhibition of the inflammasome as a potential therapeutic strategy.
Adaptation of photosystem II to high and low light in wild-type and triazine-resistant Canola plants: analysis by a fluorescence induction algorithm
Rensen, J.J.S. van; Vredenberg, W.J. - \ 2011
Photosynthesis Research 108 (2011)2-3. - ISSN 0166-8595 - p. 191 - 200.
brassica-napus l - chenopodium-album - chloroplasts - photoinhibition - kinetics - photosynthesis - turnover - oxygen - photoinactivation - cyanobacteria
Plants of wild-type and triazine-resistant Canola (Brassica napus L.) were exposed to very high light intensities and after 1 day placed on a laboratory table at low light to recover, to study the kinetics of variable fluorescence after light, and after dark-adaptation. This cycle was repeated several times. The fast OJIP fluorescence rise curve was measured immediately after light exposure and after recovery during 1 day in laboratory room light. A fluorescence induction algorithm has been used for resolution and analysis of these curves. This algorithm includes photochemical and photo-electrochemical quenching release components and a photo-electrical dependent IP-component. The analysis revealed a substantial suppression of the photo-electrochemical component (even complete in the resistant biotype), a partial suppression of the photochemical component and a decrease in the fluorescence parameter Fo after high light. These effects were recovered after 1 day in the indoor light.
The inflammasome-mediated caspase-1 activation controls adipocyte differentiation and insulin sensitivity
Stienstra, R. ; Joosten, L.A. ; Koenen, T. ; Tits, B. van; Diepen, J.A. van; Berg, S.A.A. van den; Rensen, P.C. ; Voshol, P.J. ; Fantuzzi, G. ; Hijmans, A. ; Kersten, A.H. ; Müller, M.R. ; Berg, W.B. van den; Rooijen, N. van; Wabitsch, M. ; Kullberg, B.J. ; Meer, J.W. van der; Kanneganti, T. ; Tack, C.J. ; Netea, M.G. - \ 2010
Cell Metabolism 12 (2010)6. - ISSN 1550-4131 - p. 593 - 605.
innate immunity - adipose-tissue - ppar-gamma - resistance - obesity - mice - murine - coactivators - inhibition - receptors
Obesity-induced inflammation originating from expanding adipose tissue interferes with insulin sensitivity. Important metabolic effects have been recently attributed to IL-1ß and IL-18, two members of the IL-1 family of cytokines. Processing of IL-1ß and IL-18 requires cleavage by caspase-1, a cysteine protease regulated by a protein complex called the inflammasome. We demonstrate that the inflammasome/caspase-1 governs adipocyte differentiation and insulin sensitivity. Caspase-1 is upregulated during adipocyte differentiation and directs adipocytes toward a more insulin-resistant phenotype. Treatment of differentiating adipocytes with recombinant IL-1ß and IL-18, or blocking their effects by inhibitors, reveals that the effects of caspase-1 on adipocyte differentiation are largely conveyed by IL-1ß. Caspase-1 and IL-1ß activity in adipose tissue is increased both in diet-induced and genetically induced obese animal models. Conversely, mice deficient in caspase-1 are more insulin sensitive as compared to wild-type animals. In addition, differentiation of preadipocytes isolated from caspase-1(-/-) or NLRP3(-/-) mice resulted in more metabolically active fat cells. In vivo, treatment of obese mice with a caspase-1 inhibitor significantly increases their insulin sensitivity. Indirect calorimetry analysis revealed higher fat oxidation rates in caspase-1(-/-) animals. In conclusion, the inflammasome is an important regulator of adipocyte function and insulin sensitivity, and caspase-1 inhibition may represent a novel therapeutic target in clinical conditions associated with obesity and insulin resistance
Higher concentration of QB-nonreducing photosystem II centers in triazine-resistant Chenopodium album plants as revealed by analysis of chlorophyll fluorescence kinetics
Rensen, J.J.S. van; Vredenberg, W.J. - \ 2009
Journal of Plant Physiology 166 (2009). - ISSN 0176-1617 - p. 1616 - 1623.
a fluorescence - herbicide resistance - reducing side - induction - chloroplasts - photoinhibition - cyanobacteria - biotypes - atrazine - leaves
Plants resistant to triazine-type herbicides are known to be altered in their photosystem II reaction center. Serine at site 264 in D1 protein is replaced by glycine. The measurements of chlorophyll a fluorescence excitations with a variable number of saturating flashes in Chenopodium album plants show characteristic differences between the resistant and the wild-type plants. These differences appear in response to the first flash as well as in the rise pattern of subsequent flashes of a 12.5 Hz flash train. The differences indicate a higher concentration of QB-nonreducing reaction centers in the resistant biotype, and confirm earlier results on a slower rate of electron transport between the primary and secondary electron acceptors.
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