Pyruvate controls the checkpoint inhibitor PD-L1 and suppresses T cell immunity

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Abstract

Patients with coronary artery disease (CAD) are at high risk for reactivation of the varicella zoster virus (VZV) and development of herpes zoster (HZ). Here, we found that macrophages from patients with CAD actively suppress T cell activation and expansion, leading to defective VZV-specific T cell immunity. Monocyte-derived and plaque-infiltrating macrophages from patients with CAD spontaneously expressed high surface density of the immunoinhibitory ligand programmed death ligand-1 (PD-L1), thereby providing negative signals to programmed death-1+ (PD-1+) T cells. We determined that aberrant PD-L1 expression in patient-derived macrophages was metabolically controlled. Oversupply of the glycolytic intermediate pyruvate in mitochondria from CAD macrophages promoted expression of PD-L1 via induction of the bone morphogenetic protein 4/phosphorylated SMAD1/5/IFN regulatory factor 1 (BMP4/p-SMAD1/5/IRF1) signaling pathway. Thus, CAD macrophages respond to nutrient excess by activating the immunoinhibitory PD-1/PD-L1 checkpoint, leading to impaired T cell immunity. This finding indicates that metabolite-based immunotherapy may be a potential strategy for restoring adaptive immunity in CAD.

Authors

Ryu Watanabe, Tsuyoshi Shirai, Hong Namkoong, Hui Zhang, Gerald J. Berry, Barbara B. Wallis, Benedikt Schaefgen, David G. Harrison, Jennifer A. Tremmel, John C. Giacomini, Jörg J. Goronzy, Cornelia M. Weyand

Metabolic shifts in residual breast cancer drive tumor recurrence

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Abstract

Tumor recurrence is the leading cause of breast cancer–related death. Recurrences are largely driven by cancer cells that survive therapeutic intervention. This poorly understood population is referred to as minimal residual disease. Here, using mouse models that faithfully recapitulate human disease together with organoid cultures, we have demonstrated that residual cells acquire a transcriptionally distinct state from normal epithelium and primary tumors. Gene expression changes and functional characterization revealed altered lipid metabolism and elevated ROS as hallmarks of the cells that survive tumor regression. These residual cells exhibited increased oxidative DNA damage, potentiating the acquisition of somatic mutations during hormonal-induced expansion of the mammary cell population. Inhibition of either cellular fatty acid synthesis or fatty acid transport into mitochondria reduced cellular ROS levels and DNA damage, linking these features to lipid metabolism. Direct perturbation of these hallmarks in vivo, either by scavenging ROS or by halting the cyclic mammary cell population expansion, attenuated tumor recurrence. Finally, these observations were mirrored in transcriptomic and histological signatures of residual cancer cells from neoadjuvant-treated breast cancer patients. These results highlight the potential of lipid metabolism and ROS as therapeutic targets for reducing tumor recurrence in breast cancer patients.

Authors

Kristina M. Havas, Vladislava Milchevskaya, Ksenija Radic, Ashna Alladin, Eleni Kafkia, Marta Garcia, Jens Stolte, Bernd Klaus, Nicole Rotmensz, Toby J. Gibson, Barbara Burwinkel, Andreas Schneeweiss, Giancarlo Pruneri, Kiran R. Patil, Rocio Sotillo, Martin Jechlinger

Hepatic metal ion transporter ZIP8 regulates manganese homeostasis and manganese-dependent enzyme activity

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Abstract

Genetic variants at the solute carrier family 39 member 8 (SLC39A8) gene locus are associated with the regulation of whole-blood manganese (Mn) and multiple physiological traits. SLC39A8 encodes ZIP8, a divalent metal ion transporter best known for zinc transport. Here, we hypothesized that ZIP8 regulates Mn homeostasis and Mn-dependent enzymes to influence metabolism. We generated Slc39a8-inducible global-knockout (ZIP8-iKO) and liver-specific–knockout (ZIP8-LSKO) mice and observed markedly decreased Mn levels in multiple organs and whole blood of both mouse models. By contrast, liver-specific overexpression of human ZIP8 (adeno-associated virus–ZIP8 [AAV-ZIP8]) resulted in increased tissue and whole blood Mn levels. ZIP8 expression was localized to the hepatocyte canalicular membrane, and bile Mn levels were increased in ZIP8-LSKO and decreased in AAV-ZIP8 mice. ZIP8-LSKO mice also displayed decreased liver and kidney activity of the Mn-dependent enzyme arginase. Both ZIP8-iKO and ZIP8-LSKO mice had defective protein N-glycosylation, and humans homozygous for the minor allele at the lead SLC39A8 variant showed hypogalactosylation, consistent with decreased activity of another Mn-dependent enzyme, β-1,4-galactosyltransferase. In summary, hepatic ZIP8 reclaims Mn from bile and regulates whole-body Mn homeostasis, thereby modulating the activity of Mn-dependent enzymes. This work provides a mechanistic basis for the association of SLC39A8 with whole-blood Mn, potentially linking SLC39A8 variants with other physiological traits.

Authors

Wen Lin, David R. Vann, Paschalis-Thomas Doulias, Tao Wang, Gavin Landesberg, Xueli Li, Emanuela Ricciotti, Rosario Scalia, Miao He, Nicholas J. Hand, Daniel J. Rader

Intermittent glucocorticoid steroid dosing enhances muscle repair without eliciting muscle atrophy

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Abstract

Glucocorticoid steroids such as prednisone are prescribed for chronic muscle conditions such as Duchenne muscular dystrophy, where their use is associated with prolonged ambulation. The positive effects of chronic steroid treatment in muscular dystrophy are paradoxical because these steroids are also known to trigger muscle atrophy. Chronic steroid use usually involves once-daily dosing, although weekly dosing in children has been suggested for its reduced side effects on behavior. In this work, we tested steroid dosing in mice and found that a single pulse of glucocorticoid steroids improved sarcolemmal repair through increased expression of annexins A1 and A6, which mediate myofiber repair. This increased expression was dependent on glucocorticoid response elements upstream of annexins and was reinforced by the expression of forkhead box O1 (FOXO1). We compared weekly versus daily steroid treatment in mouse models of acute muscle injury and in muscular dystrophy and determined that both regimens provided comparable benefits in terms of annexin gene expression and muscle repair. However, daily dosing activated atrophic pathways, including F-box protein 32 (Fbxo32), which encodes atrogin-1. Conversely, weekly steroid treatment in mdx mice improved muscle function and histopathology and concomitantly induced the ergogenic transcription factor Krüppel-like factor 15 (Klf15) while decreasing Fbxo32. These findings suggest that intermittent, rather than daily, glucocorticoid steroid regimen promotes sarcolemmal repair and muscle recovery from injury while limiting atrophic remodeling.

Authors

Mattia Quattrocelli, David Y. Barefield, James L. Warner, Andy H. Vo, Michele Hadhazy, Judy U. Earley, Alexis R. Demonbreun, Elizabeth M. McNally

Increased salt consumption induces body water conservation and decreases fluid intake

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Abstract

BACKGROUND. The idea that increasing salt intake increases drinking and urine volume is widely accepted. We tested the hypothesis that an increase in salt intake of 6 g/d would change fluid balance in men living under ultra-long-term controlled conditions.

METHODS. Over the course of 2 separate space flight simulation studies of 105 and 205 days’ duration, we exposed 10 healthy men to 3 salt intake levels (12, 9, or 6 g/d). All other nutrients were maintained constant. We studied the effect of salt-driven changes in mineralocorticoid and glucocorticoid urinary excretion on day-to-day osmolyte and water balance.

RESULTS. A 6-g/d increase in salt intake increased urine osmolyte excretion, but reduced free-water clearance, indicating endogenous free water accrual by urine concentration. The resulting endogenous water surplus reduced fluid intake at the 12-g/d salt intake level. Across all 3 levels of salt intake, half-weekly and weekly rhythmical mineralocorticoid release promoted free water reabsorption via the renal concentration mechanism. Mineralocorticoid-coupled increases in free water reabsorption were counterbalanced by rhythmical glucocorticoid release, with excretion of endogenous osmolyte and water surplus by relative urine dilution. A 6-g/d increase in salt intake decreased the level of rhythmical mineralocorticoid release and elevated rhythmical glucocorticoid release. The projected effect of salt-driven hormone rhythm modulation corresponded well with the measured decrease in water intake and an increase in urine volume with surplus osmolyte excretion.

CONCLUSION. Humans regulate osmolyte and water balance by rhythmical mineralocorticoid and glucocorticoid release, endogenous accrual of surplus body water, and precise surplus excretion.

FUNDING. Federal Ministry for Economics and Technology/DLR; the Interdisciplinary Centre for Clinical Research; the NIH; the American Heart Association (AHA); the Renal Research Institute; and the TOYOBO Biotechnology Foundation. Food products were donated by APETITO, Coppenrath und Wiese, ENERVIT, HIPP, Katadyn, Kellogg, Molda, and Unilever.

Authors

Natalia Rakova, Kento Kitada, Kathrin Lerchl, Anke Dahlmann, Anna Birukov, Steffen Daub, Christoph Kopp, Tetyana Pedchenko, Yahua Zhang, Luis Beck, Bernd Johannes, Adriana Marton, Dominik N. Müller, Manfred Rauh, Friedrich C. Luft, Jens Titze

High salt intake reprioritizes osmolyte and energy metabolism for body fluid conservation

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Abstract

Natriuretic regulation of extracellular fluid volume homeostasis includes suppression of the renin-angiotensin-aldosterone system, pressure natriuresis, and reduced renal nerve activity, actions that concomitantly increase urinary Na⁺ excretion and lead to increased urine volume. The resulting natriuresis-driven diuretic water loss is assumed to control the extracellular volume. Here, we have demonstrated that urine concentration, and therefore regulation of water conservation, is an important control system for urine formation and extracellular volume homeostasis in mice and humans across various levels of salt intake. We observed that the renal concentration mechanism couples natriuresis with correspondent renal water reabsorption, limits natriuretic osmotic diuresis, and results in concurrent extracellular volume conservation and concentration of salt excreted into urine. This water-conserving mechanism of dietary salt excretion relies on urea transporter–driven urea recycling by the kidneys and on urea production by liver and skeletal muscle. The energy-intense nature of hepatic and extrahepatic urea osmolyte production for renal water conservation requires reprioritization of energy and substrate metabolism in liver and skeletal muscle, resulting in hepatic ketogenesis and glucocorticoid-driven muscle catabolism, which are prevented by increasing food intake. This natriuretic-ureotelic, water-conserving principle relies on metabolism-driven extracellular volume control and is regulated by concerted liver, muscle, and renal actions.

Authors

Kento Kitada, Steffen Daub, Yahua Zhang, Janet D. Klein, Daisuke Nakano, Tetyana Pedchenko, Louise Lantier, Lauren M. LaRocque, Adriana Marton, Patrick Neubert, Agnes Schröder, Natalia Rakova, Jonathan Jantsch, Anna E. Dikalova, Sergey I. Dikalov, David G. Harrison, Dominik N. Müller, Akira Nishiyama, Manfred Rauh, Raymond C. Harris, Friedrich C. Luft, David H. Wassermann, Jeff M. Sands, Jens Titze

Folate cycle enzyme MTHFD1L confers metabolic advantages in hepatocellular carcinoma

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Abstract

Cancer cells preferentially utilize glucose and glutamine, which provide macromolecules and antioxidants that sustain rapid cell division. Metabolic reprogramming in cancer drives an increased glycolytic rate that supports maximal production of these nutrients. The folate cycle, through transfer of a carbon unit between tetrahydrofolate and its derivatives in the cytoplasmic and mitochondrial compartments, produces other metabolites that are essential for cell growth, including nucleotides, methionine, and the antioxidant NADPH. Here, using hepatocellular carcinoma (HCC) as a cancer model, we have observed a reduction in growth rate upon withdrawal of folate. We found that an enzyme in the folate cycle, methylenetetrahydrofolate dehydrogenase 1–like (MTHFD1L), plays an essential role in support of cancer growth. We determined that MTHFD1L is transcriptionally activated by NRF2, a master regulator of redox homeostasis. Our observations further suggest that MTHFD1L contributes to the production and accumulation of NADPH to levels that are sufficient to combat oxidative stress in cancer cells. The elevation of oxidative stress through MTHFD1L knockdown or the use of methotrexate, an antifolate drug, sensitizes cancer cells to sorafenib, a targeted therapy for HCC. Taken together, our study identifies MTHFD1L in the folate cycle as an important metabolic pathway in cancer cells with the potential for therapeutic targeting.

Authors

Derek Lee, Iris Ming-Jing Xu, David Kung-Chun Chiu, Robin Kit-Ho Lai, Aki Pui-Wah Tse, Lynna Lan Li, Cheuk-Ting Law, Felice Ho-Ching Tsang, Larry Lai Wei, Cerise Yuen-Ki Chan, Chun-Ming Wong, Irene Oi-Lin Ng, Carmen Chak-Lui Wong

Glutaminase and poly(ADP-ribose) polymerase inhibitors suppress pyrimidine synthesis and VHL-deficient renal cancers

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Abstract

Many cancer-associated mutations that deregulate cellular metabolic responses to hypoxia also reprogram carbon metabolism to promote utilization of glutamine. In renal cell carcinoma (RCC), cells deficient in the von Hippel–Lindau (VHL) tumor suppressor gene use glutamine to generate citrate and lipids through reductive carboxylation (RC) of α-ketoglutarate (αKG). Glutamine can also generate aspartate, the carbon source for pyrimidine biosynthesis, and glutathione for redox balance. Here we have shown that VHL^–/– RCC cells rely on RC-derived aspartate to maintain de novo pyrimidine biosynthesis. Glutaminase 1 (GLS1) inhibitors depleted pyrimidines and increased ROS in VHL^–/– cells but not in VHL^+/+ cells, which utilized glucose oxidation for glutamate and aspartate production. GLS1 inhibitor–induced nucleoside depletion and ROS enhancement led to DNA replication stress and activation of an intra–S phase checkpoint, and suppressed the growth of VHL^–/– RCC cells. These effects were rescued by administration of glutamate, αKG, or nucleobases with N-acetylcysteine. Further, we observed that the poly(ADP-ribose) polymerase (PARP) inhibitor olaparib synergizes with GLS1 inhibitors to suppress the growth of VHL^–/– cells in vitro and in vivo. This work describes a mechanism that explains the sensitivity of RCC tumor growth to GLS1 inhibitors and supports the development of therapeutic strategies for targeting VHL-deficient RCC.

Authors

Arimichi Okazaki, Paulo A. Gameiro, Danos Christodoulou, Laura Laviollette, Meike Schneider, Frances Chaves, Anat Stemmer-Rachamimov, Stephanie A. Yazinski, Richard Lee, Gregory Stephanopoulos, Lee Zou, Othon Iliopoulos

HDAC6-mediated acetylation of lipid droplet–binding protein CIDEC regulates fat-induced lipid storage

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Abstract

Obesity is characterized by aberrant fat accumulation. However, the intracellular signaling pathway that senses dietary fat and leads to fat storage remains elusive. Here, we have observed that the levels of histone deacetylase 6 (HDAC6) and the related family member HDAC10 are markedly reduced in adipose tissues of obese animals and humans. Mice with adipocyte-specific depletion of Hdac6 exhibited increased fat accumulation and reduced insulin sensitivity. In normal adipocytes, we found that reversal of P300/CBP-associated factor–induced (PCAF-induced) acetylation at K56 on cell death-inducing DFFA-like effector C (CIDEC, also known as FSP27) critically regulated lipid droplet fusion and lipid storage. Importantly, HDAC6 deacetylates CIDEC, leading to destabilization and reduced lipid droplet fusion. Accordingly, we observed elevated levels of CIDEC and its acetylated form in HDAC-deficient adipocytes as well as the adipose tissue of obese animals and humans. Fatty acids (FAs) prevented CIDEC deacetylation by promoting the dissociation of CIDEC from HDAC6, which resulted in increased association of CIDEC with PCAF on the endoplasmic reticulum. Control of CIDEC acetylation required the conversion of FAs to triacylglycerols. Thus, we have revealed a signaling axis that is involved in the coordination of nutrient availability, protein acetylation, and cellular lipid metabolic responses.

Authors

Hui Qian, Yuanying Chen, Zongqian Nian, Lu Su, Haoyong Yu, Feng-Jung Chen, Xiuqin Zhang, Wenyi Xu, Linkang Zhou, Jiaming Liu, Jinhai Yu, Luxin Yu, Yan Gao, Hongchao Zhang, Haihong Zhang, Shimin Zhao, Li Yu, Rui-Ping Xiao, Yuqian Bao, Shaocong Hou, Pingping Li, Jiada Li, Haiteng Deng, Weiping Jia, Peng Li

Sirtuin 2 regulates cellular iron homeostasis via deacetylation of transcription factor NRF2

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Abstract

SIRT2 is a cytoplasmic sirtuin that plays a role in various cellular processes, including tumorigenesis, metabolism, and inflammation. Since these processes require iron, we hypothesized that SIRT2 directly regulates cellular iron homeostasis. Here, we have demonstrated that SIRT2 depletion results in a decrease in cellular iron levels both in vitro and in vivo. Mechanistically, we determined that SIRT2 maintains cellular iron levels by binding to and deacetylating nuclear factor erythroid-derived 2–related factor 2 (NRF2) on lysines 506 and 508, leading to a reduction in total and nuclear NRF2 levels. The reduction in nuclear NRF2 leads to reduced ferroportin 1 (FPN1) expression, which in turn results in decreased cellular iron export. Finally, we observed that Sirt2 deletion reduced cell viability in response to iron deficiency. Moreover, livers from Sirt2^–/– mice had decreased iron levels, while this effect was reversed in Sirt2^–/– Nrf2^–/– double-KO mice. Taken together, our results uncover a link between sirtuin proteins and direct control over cellular iron homeostasis via regulation of NRF2 deacetylation and stability.

Authors

Xiaoyan Yang, Seong-Hoon Park, Hsiang-Chun Chang, Jason S. Shapiro, Athanassios Vassilopoulos, Konrad T. Sawicki, Chunlei Chen, Meng Shang, Paul W. Burridge, Conrad L. Epting, Lisa D. Wilsbacher, Supak Jenkitkasemwong, Mitchell Knutson, David Gius, Hossein Ardehali