The composition of microbial communities is commonly determined by sequence analyses of one of the variable (V) regions in the bacterial 16S rRNA gene. We aimed to assess whether sequencing the... Show moreThe composition of microbial communities is commonly determined by sequence analyses of one of the variable (V) regions in the bacterial 16S rRNA gene. We aimed to assess whether sequencing the full-length versus the V4 region of the 16S rRNA gene affected the results and interpretation of an experiment. To test this, mice were fed a diet without and with the prebiotic inulin and from cecum samples, two primary data sets were generated: (1) a 16S rRNA full-length data set generated by the PacBio platform; (2) a 16S rRNA V4 region data set generated by the Illumina MiSeq platform. A third derived data set was generated by in silico extracting the 16S rRNA V4 region data from the 16S rRNA full-length PacBio data set. Analyses of the primary and derived 16S rRNA V4 region data indicated similar bacterial abundances, and alpha- and beta-diversity. However, comparison of the 16S rRNA full-length data with the primary and derived 16S rRNA V4 region data revealed differences in relative bacterial abundances, and alpha- and beta-diversity. We conclude that the sequence length of 16S rRNA gene and not the sequence analysis platform affected the results and may lead to different interpretations of the effect of an intervention that affects the microbiota. Show less
Katiraei, S.; Diepen, J.A. van; Tavares, L.P.; Hoving, L.R.; Pronk, A.; Verschueren, I.; ... ; Harmelen, V. van 2022
Bone marrow transplantation (BMT) involves conditioning regimens which acutely induce side effects, including systemic inflammation, intestinal damage and shifts in the gut microbial composition,... Show moreBone marrow transplantation (BMT) involves conditioning regimens which acutely induce side effects, including systemic inflammation, intestinal damage and shifts in the gut microbial composition, some of which may persist chronically. As the gut microbiota affect systemic immune responses, we aimed to investigate whether, post-BMT, the peripheral immune system is modulated as a direct consequence of alterations in the gut microbiota. We show that 24 weeks post-BMT, splenocytes but not peritoneal macrophages display increased cytokine response patterns upon ex-vivo stimulation with various pathogens as compared to untreated controls. The pattern of BMT-induced cytokine responses was transferred to splenocytes, and not to peritoneal macrophages, of healthy controls via co-housing and transferred to germfree mice via transplantation of cecum content. Thus, BMT induces changes in gut microbiota that in their turn increase cytokine responsiveness of splenocytes. Thus, BMT establishes a dominant microbiota that attenuates normalization of the immune-response. Show less
Panhuis, W.I.H.; Tsaalbi-Shtylik, A.; Schonke, M.; Harmelen, V. van; Pronk, A.C.M.; Streefland, T.C.M.; ... ; Kooijman, S. 2022
DNA damage responses compete for cellular resources with metabolic pathways, but little is known about the metabolic consequences of impaired DNA replication, a process called replication stress.... Show moreDNA damage responses compete for cellular resources with metabolic pathways, but little is known about the metabolic consequences of impaired DNA replication, a process called replication stress. Here we characterized the metabolic consequences of DNA replication stress at endogenous DNA lesions by using mice with a disruption of Rev1, a translesion DNA polymerase specialized in the mutagenic replication of damaged DNA. Male and female Rev1 knockout (KO) mice were compared with wild-type (WT) mice and followed over time to study the natural course of body weight gain and glucose tolerance. Follow-up measurements were performed in female mice for in-depth metabolic characterization. Body weight and fat mass were only increased in female KO mice versus WT mice, whereas glucose intolerance and a reduction in lean mass were observed in both sexes. Female KO mice showed reduced locomotor activity while male KO mice showed increased activity as compared with their WT littermates. Further characterization of female mice revealed that lipid handling was unaffected by Rev1 deletion. An increased respiratory exchange ratio, combined with elevated plasma lactate levels and increased hepatic gluconeogenesis indicated problems with aerobic oxidation and increased reliance on anaerobic glycolysis. Supplementation with the NAD (+) precursor nicotinamide riboside to stimulate aerobic respiration failed to restore the metabolic phenotype. In conclusion, replication stress at endogenous DNA lesions induces a complex metabolic phenotype, most likely initiated by muscular metabolic dysfunction and increased dependence on anaerobic glycolysis. Nicotinamide riboside supplementation after the onset of the metabolic impairment did not rescue this phenotype.NEW & NOTEWORTHY An increasing number of DNA lesions interferes with cellular replication leading to metabolic inflexibility. We utilized Rev1 knockout mice as a model for replication stress, and show a sex-dependent metabolic phenotype, with a pronounced reduction of lean mass and glucose tolerance. These data indicate that in obesity, we may end up in an infinite loop where metabolic disturbance promotes the formation of DNA lesions, which in turn interferes with cellular replication causing further metabolic disturbances. Show less
Embgenbroich, M.; Zande, H.J.P. van der; Hussaarts, L.; Schulte-Schrepping, J.; Pelgrom, L.R.; Garcia-Tardon, N.; ... ; Burgdorf, S. 2021
Proinflammatory activation of macrophages in metabolic tissues is critically important in the induction of obesity-induced metaflammation. Here, we demonstrate that the soluble mannose receptor ... Show moreProinflammatory activation of macrophages in metabolic tissues is critically important in the induction of obesity-induced metaflammation. Here, we demonstrate that the soluble mannose receptor (sMR) plays a direct functional role in both macrophage activation and metaflammation. We show that sMR binds CD45 on macrophages and inhibits its phosphatase activity, leading to an Src/Akt/ NF-kappa B-mediated cellular reprogramming toward an inflammatory phenotype both in vitro and in vivo. Remarkably, increased serum sMR levels were observed in obese mice and humans and directly correlated with body weight. Importantly, enhanced sMR levels increase serum proinflammatory cytokines, activate tissue macrophages, and promote insulin resistance. Altogether, our results reveal sMR as regulator of proinflammatory macrophage activation, which could constitute a therapeutic target for metaflammation and other hyperinflammatory diseases. Show less
Katiraei, S.; Vries, M.R. de; Costain, A.H.; Thiem, K.; Hoving, L.R.; Diepen, J.A. van; ... ; Harmelen, V. van 2019
Scope Akkermansia muciniphila (A. muciniphila) is an intestinal commensal with anti-inflammatory properties both in the intestine and other organs. The aim is to investigate the effects of oral... Show moreScope Akkermansia muciniphila (A. muciniphila) is an intestinal commensal with anti-inflammatory properties both in the intestine and other organs. The aim is to investigate the effects of oral administration of A. muciniphila on lipid metabolism, immunity, and cuff-induced neointima formation in hyperlipidemic APOE*3-Leiden (E3L).CETP mice. Methods and results Hyperlipidemic male E3L.CETP mice are daily treated with 2 x 10(8) CFU A. muciniphila by oral gavage for 4 weeks and the effects are determined on plasma lipid levels, immune parameters, and cuff-induced neointima formation and composition. A. muciniphila administration lowers body weight and plasma total cholesterol and triglycerides levels. A. muciniphila influences the immune cell composition in mesenteric lymph nodes, as evident from an increased total B cell population, while reducing the total T cell and neutrophil populations. Importantly, A. muciniphila reduces the expression of the activation markers MHCII on dendritic cells and CD86 on B cells. A. muciniphila also increases whole blood ex vivo lipopolysaccharide-stimulated IL-10 release. Finally, although treatment with A. muciniphila improves lipid metabolism and immunity, it does not affect neointima formation or composition. Conclusions Four weeks of treatment with A. muciniphila exerts lipid-lowering and immunomodulatory effects, which are insufficient to inhibit neointima formation in hyperlipidemic E3L.CETP mice. Show less
Nahon, J.E.; Hoekstra, M.; Harmelen, V. van; Rensen, P.C.N.; Dijk, K.W. van; Kooijman, S.; Eck, M. van 2019
ObjectiveProteoglycan 4 (Prg4) has emerged from human association studies as a possible factor contributing to weight gain, dyslipidemia and insulin resistance. In the current study, we... Show moreObjectiveProteoglycan 4 (Prg4) has emerged from human association studies as a possible factor contributing to weight gain, dyslipidemia and insulin resistance. In the current study, we investigated the causal role of Prg4 in controlling lipid and glucose metabolism in mice.MethodsPrg4 knockout (KO) mice and wild-type (WT) littermates were challenged with an obesogenic high-fat diet (45% of total calories as fat) for 16 weeks. To further stimulate the development of metabolic alterations, 10% fructose water was provided starting from week 13.ResultsPrg4 deficiency only tended to reduce diet-induced body weight gain, but significantly improved glucose handling (AUC: −29%; p < 0.05), which was also reflected by a tendency towards a reduced HOMA-IR score (−49%; p = 0.06 as compared to WT mice). This coincided with lower hepatic expression of glycolysis (Gck: −30%; p < 0.05) and lipogenesis (Acc: −21%; p < 0.05 and Scd1: −38%; p < 0.001) genes, which translated in significantly lower hepatic triglyceride levels (−56%; p < 0.001) in Prg4 KO mice as compared to WT mice. Prg4 KO mice likely had lower glucose utilization by skeletal muscle as compared to WT mice, judged by a significant reduction in the genes Glut4 (−29%; p < 0.01), Pfkm (−21%; p < 0.05) and Hk2 (−39%; p < 0.001). Moreover, Prg4 KO mice showed a favorable white adipose tissue phenotype with lower uptake of triglyceride-derived fatty acids (−46%; p < 0.05) and lower gene expression of inflammatory markers Cd68, Mcp1 and Tnfα (−65%, −81% and −63%, respectively; p < 0.01) than WT mice.ConclusionPrg4 KO mice are protected from high-fat diet-induced glucose intolerance and fatty liver disease. Show less
Hoving, L.R.; Katiraei, S.; Pronk, A.; Heijink, M.; Vonk, K.K.D.; Amghar-el Bouazzaoui, F.; ... ; Dijk, K.W. van 2018
Conclusions: BCG reduces plasma nonHDL-cholesterol levels and delays atherosclerotic lesion formation in hyperlipidemic mice. (C) 2016 The Authors. Published by Elsevier Ireland Ltd. This is an... Show moreConclusions: BCG reduces plasma nonHDL-cholesterol levels and delays atherosclerotic lesion formation in hyperlipidemic mice. (C) 2016 The Authors. Published by Elsevier Ireland Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Show less
Heuvel, J.K. van den; Boon, M.R.; Hengel, I. van; Peschier-van der Put, E.; Beek, L. van; Harmelen, V. van; ... ; Meijer, O.C. 2016
C108297 attenuates obesity by reducing caloric intake and increasing lipolysis and fat oxidation, and in addition attenuates inflammation. These data suggest that selective GR modulation may be a... Show moreC108297 attenuates obesity by reducing caloric intake and increasing lipolysis and fat oxidation, and in addition attenuates inflammation. These data suggest that selective GR modulation may be a viable strategy for the reduction of diet-induced obesity and inflammation. Show less
