Anita Reddy

All Publications

• Monocarboxylate transporters facilitate succinate uptake into brown adipocytes. Nature metabolism Reddy, A., Winther, S., Tran, N., Xiao, H., Jakob, J., Garrity, R., Smith, A., Ordonez, M., Laznik-Bogoslavski, D., Rothstein, J. D., Mills, E. L., Chouchani, E. T. 2024; 6 (3): 567-577

  Abstract

  Uptake of circulating succinate by brown adipose tissue (BAT) and beige fat elevates whole-body energy expenditure, counteracts obesity and antagonizes systemic tissue inflammation in mice. The plasma membrane transporters that facilitate succinate uptake in these adipocytes remain undefined. Here we elucidate a mechanism underlying succinate import into BAT via monocarboxylate transporters (MCTs). We show that succinate transport is strongly dependent on the proportion that is present in the monocarboxylate form. MCTs facilitate monocarboxylate succinate uptake, which is promoted by alkalinization of the cytosol driven by adrenoreceptor stimulation. In brown adipocytes, we show that MCT1 primarily facilitates succinate import. In male mice, we show that both acute pharmacological inhibition of MCT1 and congenital depletion of MCT1 decrease succinate uptake into BAT and consequent catabolism. In sum, we define a mechanism of succinate uptake in BAT that underlies its protective activity in mouse models of metabolic disease.

  View details for DOI 10.1038/s42255-024-00981-5

  View details for PubMedID 38378996

  View details for PubMedCentralID 9150600

• Lactate regulates cell cycle by remodeling the anaphase promoting complex. Nature Liu, W., Wang, Y., Bozi, L. H., Fischer, P., Jedrychowski, M. P., Xiao, H., Wu, T., Darabedian, N., He, X., Mills, E. L., Burger, N., Shin, S., Reddy, A., Sprenger, H. G., Tran, N., Winther, S., Hinshaw, S. M., Shen, J., Seo, H. S., Song, K., Xu, A. Z., Sebastian, L., Zhao, J., Dhe-Paganon, S., Che, J., Gygi, S. P., Arthanari, H., Chouchani, E. T. 2023

  Abstract

  Lactate is abundant in rapidly dividing cells due to the requirement for elevated glucose catabolism to support proliferation1-6. However, it is not known whether accumulated lactate affects the proliferative state. Here, we deploy a systematic approach to determine lactate-dependent regulation of proteins across the human proteome. From these data, we elucidate a mechanism of cell cycle regulation whereby accumulated lactate remodels the anaphase promoting complex (APC/C). Remodeling of APC/C in this way is caused by direct inhibition of the SUMO protease SENP1 by lactate. We discover that accumulated lactate binds and inhibits SENP1 by forming a complex with zinc in the SENP1 active site. SENP1 inhibition by lactate stabilizes SUMOylation of two residues on APC4, which drives UBE2C binding to APC/C. This direct regulation of APC/C by lactate stimulates timed degradation of cell cycle proteins, and efficient mitotic exit in proliferative human cells. The above mechanism is initiated upon mitotic entry when lactate abundance reaches its apex. In this way, accumulation of lactate communicates the consequences of a nutrient replete growth phase to stimulate timed opening of APC/C, cell division, and proliferation. Conversely, persistent accumulation of lactate drives aberrant APC/C remodeling and can overcome anti-mitotic pharmacology via mitotic slippage. Taken together, we define a biochemical mechanism through which lactate directly regulates protein function to control cell cycle and proliferation.

  View details for DOI 10.1038/s41586-023-05939-3

  View details for PubMedID 36921622

• Isolation of extracellular fluids reveals novel secreted bioactive proteins from muscle and fat tissues. Cell metabolism Mittenbühler, M. J., Jedrychowski, M. P., Van Vranken, J. G., Sprenger, H. G., Wilensky, S., Dumesic, P. A., Sun, Y., Tartaglia, A., Bogoslavski, D., A, M., Xiao, H., Blackmore, K. A., Reddy, A., Gygi, S. P., Chouchani, E. T., Spiegelman, B. M. 2023; 35 (3): 535-549.e7

  Abstract

  Proteins are secreted from cells to send information to neighboring cells or distant tissues. Because of the highly integrated nature of energy balance systems, there has been particular interest in myokines and adipokines. These are challenging to study through proteomics because serum or plasma contains highly abundant proteins that limit the detection of proteins with lower abundance. We show here that extracellular fluid (EF) from muscle and fat tissues of mice shows a different protein composition than either serum or tissues. Mass spectrometry analyses of EFs from mice with physiological perturbations, like exercise or cold exposure, allowed the quantification of many potentially novel myokines and adipokines. Using this approach, we identify prosaposin as a secreted product of muscle and fat. Prosaposin expression stimulates thermogenic gene expression and induces mitochondrial respiration in primary fat cells. These studies together illustrate the utility of EF isolation as a discovery tool for adipokines and myokines.

  View details for DOI 10.1016/j.cmet.2022.12.014

  View details for PubMedID 36681077

  View details for PubMedCentralID PMC9998376

• Architecture of the outbred brown fat proteome defines regulators of metabolic physiology. Cell Xiao, H., Bozi, L. H., Sun, Y., Riley, C. L., Philip, V. M., Chen, M., Li, J., Zhang, T., Mills, E. L., Emont, M. P., Sun, W., Reddy, A., Garrity, R., Long, J., Becher, T., Vitas, L. P., Laznik-Bogoslavski, D., Ordonez, M., Liu, X., Chen, X., Wang, Y., Liu, W., Tran, N., Liu, Y., Zhang, Y., Cypess, A. M., White, A. P., He, Y., Deng, R., Schöder, H., Paulo, J. A., Jedrychowski, M. P., Banks, A. S., Tseng, Y. H., Cohen, P., Tsai, L. T., Rosen, E. D., Klein, S., Chondronikola, M., McAllister, F. E., Van Bruggen, N., Huttlin, E. L., Spiegelman, B. M., Churchill, G. A., Gygi, S. P., Chouchani, E. T. 2022

  Abstract

  Brown adipose tissue (BAT) regulates metabolic physiology. However, nearly all mechanistic studies of BAT protein function occur in a single inbred mouse strain, which has limited the understanding of generalizable mechanisms of BAT regulation over physiology. Here, we perform deep quantitative proteomics of BAT across a cohort of 163 genetically defined diversity outbred mice, a model that parallels the genetic and phenotypic variation found in humans. We leverage this diversity to define the functional architecture of the outbred BAT proteome, comprising 10,479 proteins. We assign co-operative functions to 2,578 proteins, enabling systematic discovery of regulators of BAT. We also identify 638 proteins that correlate with protection from, or sensitivity to, at least one parameter of metabolic disease. We use these findings to uncover SFXN5, LETMD1, and ATP1A2 as modulators of BAT thermogenesis or adiposity, and provide OPABAT as a resource for understanding the conserved mechanisms of BAT regulation over metabolic physiology.

  View details for DOI 10.1016/j.cell.2022.10.003

  View details for PubMedID 36334589

• Glucose metabolism and pyruvate carboxylase enhance glutathione synthesis and restrict oxidative stress in pancreatic islets. Cell reports Fu, A., van Rooyen, L., Evans, L., Armstrong, N., Avizonis, D., Kin, T., Bird, G. H., Reddy, A., Chouchani, E. T., Liesa-Roig, M., Walensky, L. D., Shapiro, A. M., Danial, N. N. 2021; 37 (8): 110037

  Abstract

  Glucose metabolism modulates the islet β cell responses to diabetogenic stress, including inflammation. Here, we probed the metabolic mechanisms that underlie the protective effect of glucose in inflammation by interrogating the metabolite profiles of primary islets from human donors and identified de novo glutathione synthesis as a prominent glucose-driven pro-survival pathway. We find that pyruvate carboxylase is required for glutathione synthesis in islets and promotes their antioxidant capacity to counter inflammation and nitrosative stress. Loss- and gain-of-function studies indicate that pyruvate carboxylase is necessary and sufficient to mediate the metabolic input from glucose into glutathione synthesis and the oxidative stress response. Altered redox metabolism and cellular capacity to replenish glutathione pools are relevant in multiple pathologies beyond obesity and diabetes. Our findings reveal a direct interplay between glucose metabolism and glutathione biosynthesis via pyruvate carboxylase. This metabolic axis may also have implications in other settings where sustaining glutathione is essential.

  View details for DOI 10.1016/j.celrep.2021.110037

  View details for PubMedID 34818536

  View details for PubMedCentralID PMC8720303

• UCP1 governs liver extracellular succinate and inflammatory pathogenesis. Nature metabolism Mills, E. L., Harmon, C., Jedrychowski, M. P., Xiao, H., Garrity, R., Tran, N. V., Bradshaw, G. A., Fu, A., Szpyt, J., Reddy, A., Prendeville, H., Danial, N. N., Gygi, S. P., Lynch, L., Chouchani, E. T. 2021; 3 (5): 604-617

  Abstract

  Non-alcoholic fatty liver disease (NAFLD), the most prevalent liver pathology worldwide, is intimately linked with obesity and type 2 diabetes. Liver inflammation is a hallmark of NAFLD and is thought to contribute to tissue fibrosis and disease pathogenesis. Uncoupling protein 1 (UCP1) is exclusively expressed in brown and beige adipocytes, and has been extensively studied for its capacity to elevate thermogenesis and reverse obesity. Here we identify an endocrine pathway regulated by UCP1 that antagonizes liver inflammation and pathology, independent of effects on obesity. We show that, without UCP1, brown and beige fat exhibit a diminished capacity to clear succinate from the circulation. Moreover, UCP1KO mice exhibit elevated extracellular succinate in liver tissue that drives inflammation through ligation of its cognate receptor succinate receptor 1 (SUCNR1) in liver-resident stellate cell and macrophage populations. Conversely, increasing brown and beige adipocyte content in mice antagonizes SUCNR1-dependent inflammatory signalling in the liver. We show that this UCP1-succinate-SUCNR1 axis is necessary to regulate liver immune cell infiltration and pathology, and systemic glucose intolerance in an obesogenic environment. As such, the therapeutic use of brown and beige adipocytes and UCP1 extends beyond thermogenesis and may be leveraged to antagonize NAFLD and SUCNR1-dependent liver inflammation.

  View details for DOI 10.1038/s42255-021-00389-5

  View details for PubMedID 34002097

  View details for PubMedCentralID PMC8207988

• pH-Gated Succinate Secretion Regulates Muscle Remodeling in Response to Exercise. Cell Reddy, A., Bozi, L. H., Yaghi, O. K., Mills, E. L., Xiao, H., Nicholson, H. E., Paschini, M., Paulo, J. A., Garrity, R., Laznik-Bogoslavski, D., Ferreira, J. C., Carl, C. S., Sjøberg, K. A., Wojtaszewski, J. F., Jeppesen, J. F., Kiens, B., Gygi, S. P., Richter, E. A., Mathis, D., Chouchani, E. T. 2020; 183 (1): 62-75.e17

  Abstract

  In response to skeletal muscle contraction during exercise, paracrine factors coordinate tissue remodeling, which underlies this healthy adaptation. Here we describe a pH-sensing metabolite signal that initiates muscle remodeling upon exercise. In mice and humans, exercising skeletal muscle releases the mitochondrial metabolite succinate into the local interstitium and circulation. Selective secretion of succinate is facilitated by its transient protonation, which occurs upon muscle cell acidification. In the protonated monocarboxylic form, succinate is rendered a transport substrate for monocarboxylate transporter 1, which facilitates pH-gated release. Upon secretion, succinate signals via its cognate receptor SUCNR1 in non-myofibrillar cells in muscle tissue to control muscle-remodeling transcriptional programs. This succinate-SUCNR1 signaling is required for paracrine regulation of muscle innervation, muscle matrix remodeling, and muscle strength in response to exercise training. In sum, we define a bioenergetic sensor in muscle that utilizes intracellular pH and succinate to coordinate tissue adaptation to exercise.

  View details for DOI 10.1016/j.cell.2020.08.039

  View details for PubMedID 32946811

  View details for PubMedCentralID PMC7778787

• A Quantitative Tissue-Specific Landscape of Protein Redox Regulation during Aging. Cell Xiao, H., Jedrychowski, M. P., Schweppe, D. K., Huttlin, E. L., Yu, Q., Heppner, D. E., Li, J., Long, J., Mills, E. L., Szpyt, J., He, Z., Du, G., Garrity, R., Reddy, A., Vaites, L. P., Paulo, J. A., Zhang, T., Gray, N. S., Gygi, S. P., Chouchani, E. T. 2020; 180 (5): 968-983.e24

  Abstract

  Mammalian tissues engage in specialized physiology that is regulated through reversible modification of protein cysteine residues by reactive oxygen species (ROS). ROS regulate a myriad of biological processes, but the protein targets of ROS modification that drive tissue-specific physiology in vivo are largely unknown. Here, we develop Oximouse, a comprehensive and quantitative mapping of the mouse cysteine redox proteome in vivo. We use Oximouse to establish several paradigms of physiological redox signaling. We define and validate cysteine redox networks within each tissue that are tissue selective and underlie tissue-specific biology. We describe a common mechanism for encoding cysteine redox sensitivity by electrostatic gating. Moreover, we comprehensively identify redox-modified disease networks that remodel in aged mice, establishing a systemic molecular basis for the long-standing proposed links between redox dysregulation and tissue aging. We provide the Oximouse compendium as a framework for understanding mechanisms of redox regulation in physiology and aging.

  View details for DOI 10.1016/j.cell.2020.02.012

  View details for PubMedID 32109415

  View details for PubMedCentralID PMC8164166

• Genomic evolution and chemoresistance in germ-cell tumours. Nature Taylor-Weiner, A., Zack, T., O'Donnell, E., Guerriero, J. L., Bernard, B., Reddy, A., Han, G. C., AlDubayan, S., Amin-Mansour, A., Schumacher, S. E., Litchfield, K., Turnbull, C., Gabriel, S., Beroukhim, R., Getz, G., Carter, S. L., Hirsch, M. S., Letai, A., Sweeney, C., Van Allen, E. M. 2016; 540 (7631): 114-118

  Abstract

  Germ-cell tumours (GCTs) are derived from germ cells and occur most frequently in the testes. GCTs are histologically heterogeneous and distinctly curable with chemotherapy. Gains of chromosome arm 12p and aneuploidy are nearly universal in GCTs, but specific somatic genomic features driving tumour initiation, chemosensitivity and progression are incompletely characterized. Here, using clinical whole-exome and transcriptome sequencing of precursor, primary (testicular and mediastinal) and chemoresistant metastatic human GCTs, we show that the primary somatic feature of GCTs is highly recurrent chromosome arm level amplifications and reciprocal deletions (reciprocal loss of heterozygosity), variations that are significantly enriched in GCTs compared to 19 other cancer types. These tumours also acquire KRAS mutations during the development from precursor to primary disease, and primary testicular GCTs (TGCTs) are uniformly wild type for TP53. In addition, by functional measurement of apoptotic signalling (BH3 profiling) of fresh tumour and adjacent tissue, we find that primary TGCTs have high mitochondrial priming that facilitates chemotherapy-induced apoptosis. Finally, by phylogenetic analysis of serial TGCTs that emerge with chemotherapy resistance, we show how TGCTs gain additional reciprocal loss of heterozygosity and that this is associated with loss of pluripotency markers (NANOG and POU5F1) in chemoresistant teratomas or transformed carcinomas. Our results demonstrate the distinct genomic features underlying the origins of this disease and associated with the chemosensitivity phenotype, as well as the rare progression to chemoresistance. These results identify the convergence of cancer genomics, mitochondrial priming and GCT evolution, and may provide insights into chemosensitivity and resistance in other cancers.

  View details for DOI 10.1038/nature20596

  View details for PubMedID 27905446

  View details for PubMedCentralID PMC5553306

• Mitochondrial Biogenesis and Proteome Remodeling Promote One-Carbon Metabolism for T Cell Activation. Cell metabolism Ron-Harel, N., Santos, D., Ghergurovich, J. M., Sage, P. T., Reddy, A., Lovitch, S. B., Dephoure, N., Satterstrom, F. K., Sheffer, M., Spinelli, J. B., Gygi, S., Rabinowitz, J. D., Sharpe, A. H., Haigis, M. C. 2016; 24 (1): 104-17

  Abstract

  Naive T cell stimulation activates anabolic metabolism to fuel the transition from quiescence to growth and proliferation. Here we show that naive CD4(+) T cell activation induces a unique program of mitochondrial biogenesis and remodeling. Using mass spectrometry, we quantified protein dynamics during T cell activation. We identified substantial remodeling of the mitochondrial proteome over the first 24 hr of T cell activation to generate mitochondria with a distinct metabolic signature, with one-carbon metabolism as the most induced pathway. Salvage pathways and mitochondrial one-carbon metabolism, fed by serine, contribute to purine and thymidine synthesis to enable T cell proliferation and survival. Genetic inhibition of the mitochondrial serine catabolic enzyme SHMT2 impaired T cell survival in culture and antigen-specific T cell abundance in vivo. Thus, during T cell activation, mitochondrial proteome remodeling generates specialized mitochondria with enhanced one-carbon metabolism that is critical for T cell activation and survival.

  View details for DOI 10.1016/j.cmet.2016.06.007

  View details for PubMedID 27411012

  View details for PubMedCentralID PMC5330619