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Aim: Chronic kidney disease (CKD) is accompanied by increased cardiovascular risk and heart failure (HF). In rodents, 2,8-dihydroxyadenine (DHA)-induced nephropathy is a frequently used CKD model. Cardiac and kidney tubular cells share high energy demand to guarantee constant contractive force of the heart or reabsorption/secretion of primary filtrated molecules and waste products by the kidney. Here we analyze time-dependent mechanisms of kidney damage and cardiac consequences under consideration of energetic pathways with the focus on mitochondrial function and lipid metabolism in mice., Methods and Results: CKD was induced by alternating dietary adenine supplementation (0.2 % or 0.05 % of adenine) in C57BL/6J mice for 9 weeks. Progressive kidney damage led to reduced creatinine clearance, kidney fibrosis and renal inflammation after 3, 6, and 9 weeks. No difference in cardiac function, mitochondrial respiration nor left ventricular fibrosis was observed at any time point. Investigating mechanisms of renal damage, protective SirT3 was decreased in CKD, which contrasted an increase in protein kinase B (AKT) expression, mechanistic target of rapamycin (mTOR) downstream signaling, induction of oxidative and endoplasmic reticulum (ER) stress. This occurred together with impaired renal mitochondrial function and accumulation of hexosylceramides (HexCer) as an established mediator of inflammation and mitochondrial dysfunction in the kidney., Conclusions: 2,8-DHA-induced CKD results in renal activation of the mTOR downstream signaling, endoplasmic reticulum stress, tubular injury, fibrosis, inflammation, oxidative stress and impaired kidney mitochondrial function in conjunction with renal hexosylceramide accumulation in C57BL/6J mice., Competing Interests: Declaration of competing interest NM has given lectures for Boehringer Ingelheim, Sanofi-Aventis, MSD, BMS, AstraZeneca, Lilly, NovoNordisk; has received unrestricted research grants from Boehringer Ingelheim, and has served as an advisor for Bayer, Boehringer Ingelheim, Sanofi-Aventis, MSD, BMS, AstraZeneca, NovoNordisk. In addition, served in trial leadership for Boehringer Ingelheim and NovoNordisk. ML received grants and personal fees from Boehringer Ingelheim, MSD, Novo Nordisk and personal fees from Amgen, Sanofi, Astra Zeneca, Bayer, Lilly, Daiichi Sankyo, Novarits. NM, HN and JJ are founding shareholders of AMICARE Development GmbH. JM, KK, BMK, DWLW, EMB, JD, JVS, CL and PB have nothing to disclose., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Introduction: Altered lipid metabolism and subsequent changes in cellular lipid composition have been observed in prostate cancer cells, are associated with poor clinical outcome, and are promising targets for metabolic therapies. This study reports for the first time on the synthesis of a phospholipid radiotracer based on the phospholipid 1,2-didocosahexaenoyl-sn-glycero-3-phosphocholine (PC44:12) to allow tracking of polyunsaturated lipid tumor uptake via PET imaging. This tracer may aid in the development of strategies to modulate response to therapies targeting lipid metabolism in prostate cancer., Methods: Lipidomics analysis of prostate tumor explants and LNCaP tumor cells were used to identify PC44:12 as a potential phospholipid candidate for radiotracer development. Synthesis of phosphocholine precursor and non-radioactive standard were optimised using click chemistry. The biodistribution of a fluorine-18 labeled analogue, N-{[4-(2-[ 18 F]fluoroethyl)-2,3,4-triazol-1-yl]methyl}-1,2-didocosahexaenoyl-sn-glycero-3-phosphocholine ([ 18 F]2) was determined in LNCaP prostate tumor-bearing NOD SCID gamma mice by ex vivo biodistribution and PET imaging studies and compared to biodistribution of [ 18 F]fluoromethylcholine., Results: [ 18 F]2 was produced with a decay-corrected yield of 17.8 ± 3.7% and an average radiochemical purity of 97.00 ± 0.89% (n = 6). Molar activity was 85.1 ± 3.45 GBq/μmol (2300 ± 93 mCi/μmol) and the total synthesis time was 2 h. Ex vivo biodistribution data demonstrated high liver uptake (41.1 ± 9.2%ID/g) and high splenic uptake (10.9 ± 9.1%ID/g) 50 min post-injection. Ex vivo biodistribution showed low absolute tumor uptake of [ 18 F]2 (0.8 ± 0.3%ID/g). However, dynamic PET imaging demonstrated an increase over time of the relative tumor-to-muscle ratio with a peak of 2.8 ± 0.5 reached 1 h post-injection. In contrast, dynamic PET of [ 18 F]fluoromethylcholine demonstrated no increase in tumor-to-muscle ratios due to an increase in both tumor and muscle over time. Absolute uptake of [ 18 F]fluoromethylcholine was higher and peaked at 60 min post injection (2.25 ± 0.29%ID/g) compared to [ 18 F]2 (1.44 ± 0.06%ID/g) during the 1 h dynamic scan period., Conclusions and Advances in Knowledge: This study demonstrates the ability to radiolabel phospholipids and indicates the potential to monitor the in vivo distribution of phospholipids using fluorine-18 based PET., (Copyright © 2020 Elsevier Inc. All rights reserved.)

We previously described the expression of CD36 and LPL by breast cancer (BC) cells and tissues and the growth-promoting effect of VLDL observed only in the presence of LPL. We now report a model in which LPL is bound to a heparan sulfate proteoglycan motif on the BC cell surface and acts in concert with the VLDL receptor to internalize VLDLs via receptor-mediated endocytosis. We also demonstrate that gene-expression programs for lipid synthesis versus uptake respond robustly to triglyceride-rich lipoprotein availability. The literature emphasizes de novo FA synthesis and exogenous free FA uptake using CD36 as paramount mechanisms for lipid acquisition by cancer cells. We find that the uptake of intact lipoproteins is also an important mechanism for lipid acquisition and that the relative reliance on lipid synthesis versus uptake varies among BC cell lines and in response to VLDL availability. This metabolic plasticity has important implications for the development of therapies aimed at the lipid dependence of many types of cancer, in that the inhibition of FA synthesis may elicit compensatory upregulation of lipid uptake. Moreover, the mechanism that we have elucidated provides a direct connection between dietary fat and tumor biology.-.

NLRP3 inflammasome plays a key role in Western diet-induced systemic inflammation and was recently shown to mediate long-lasting trained immunity in myeloid cells. Saturated fatty acids (SFAs) are sterile triggers able to induce the assembly of the NLRP3 inflammasome in macrophages, leading to IL-1β secretion while unsaturated ones (UFAs) prevent SFAs-mediated NLRP3 activation. Unlike previous studies using LPS-primed bone marrow derived macrophages, we do not see any ROS or IRE-1α involvement in SFAs-mediated NLRP3 activation in human monocytes-derived macrophages. Rather we show that SFAs need to enter the cells and to be activated into acyl-CoA to lead to NLRP3 activation in human macrophages. However, their β-oxidation is dispensable. Instead, they are channeled towards phospholipids but redirected towards lipid droplets containing triacylglycerol in the presence of UFAs. Lipidomic analyses and Laurdan fluorescence experiments demonstrate that SFAs induce a dramatic saturation of phosphatidylcholine (PC) correlated with a loss of membrane fluidity, both events inhibited by UFAs. The silencing of CCTα, the key enzyme in PC synthesis, prevents SFA-mediated NLRP3 activation, demonstrating the essential role of the de novo PC synthesis. This SFA-induced membrane remodeling promotes a disruption of the plasma membrane Na, K-ATPase, instigating a K + efflux essential and sufficient for NLRP3 activation. This work opens novel therapeutic avenues to interfere with Western diet-associated diseases such as those targeting the glycerolipid pathway., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Numerous human pathologies, including common conditions such as obesity, diabetes, cardiovascular disease, cancer, inflammatory disease and neurodegeneration, involve changes in lipid metabolism. Likewise, a growing number of drugs are being developed that directly or indirectly affect lipid metabolic pathways. Instead of classical and cumbrous radiochemical analyses, lipid profiling by mass spectrometry (MS)-based lipidomics holds great potential as companion diagnostic in several steps along the drug development process. In this review we describe some typical lipidomics set-ups and illustrate how these technologies can be implemented in target discovery, compound screening, in vitro and in vivo preclinical testing, toxicity testing of drugs, and prediction and monitoring of response., (Copyright © 2015. Published by Elsevier Ltd.)