Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes are interacting comorbidities of obesity, and increased hepatic de novo lipogenesis (DNL), driven by hyperinsulinemia and carbohydrate overload, contributes to their pathogenesis. Fatty acid synthase (FASN), a key enzyme of hepatic DNL, is upregulated in association with insulin resistance. However, the therapeutic potential of targeting FASN in hepatocytes for obesity-associated metabolic diseases is unknown. Here, we show that hepatic FASN deficiency differentially affects NAFLD and diabetes depending on the etiology of obesity. Hepatocyte-specific ablation of FASN ameliorated NAFLD and diabetes in melanocortin 4 receptor–deficient mice but not in mice with diet-induced obesity. In leptin-deficient mice, FASN ablation alleviated hepatic steatosis and improved glucose tolerance but exacerbated fed hyperglycemia and liver dysfunction. The beneficial effects of hepatic FASN deficiency on NAFLD and glucose metabolism were associated with suppression of DNL and attenuation of gluconeogenesis and fatty acid oxidation, respectively. The exacerbation of fed hyperglycemia by FASN ablation in leptin-deficient mice appeared attributable to impairment of hepatic glucose uptake triggered by glycogen accumulation and citrate-mediated inhibition of glycolysis. Further investigation of the therapeutic potential of hepatic FASN inhibition for NAFLD and diabetes in humans should thus consider the etiology of obesity.
Toshiya Matsukawa, Takashi Yagi, Tohru Uchida, Mashito Sakai, Masaru Mitsushima, Takao Naganuma, Hiroyuki Yano, Yuka Inaba, Hiroshi Inoue, Keisuke Yanagida, Masaaki Uematsu, Kazuki Nakao, Harumi Nakao, Atsu Aiba, Yoji Nagashima, Tetsuya Kubota, Naoto Kubota, Yoshihiko Izumida, Naoya Yahagi, Hiroyuki Unoki-Kubota, Yasushi Kaburagi, Shun-ichiro Asahara, Yoshiaki Kido, Hideo Shindou, Michiko Itoh, Yoshihiro Ogawa, Shiro Minami, Yasuo Terauchi, Kazuyuki Tobe, Kohjiro Ueki, Masato Kasuga, Michihiro Matsumoto
Pathogenic mutations in mitochondrial (mt) tRNA genes that compromise oxidative phosphorylation (OXPHOS) exhibit heteroplasmy and cause a range of multisyndromic conditions. Although mitochondrial disease patients are known to suffer from abnormal immune responses, how heteroplasmic mtDNA mutations affect the immune system at the molecular level is largely unknown. Here, in mice carrying pathogenic C5024T in mt-tRNAAla and in patients with mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes (MELAS) syndrome carrying A3243G in mt-tRNALeu, we found memory T and B cells to have lower pathogenic mtDNA mutation burdens than their antigen-inexperienced naive counterparts, including after vaccination. Pathogenic burden reduction was less pronounced in myeloid compared with lymphoid lineages, despite C5024T compromising macrophage OXPHOS capacity. Rapid dilution of the C5024T mutation in T and B cell cultures could be induced by antigen receptor–triggered proliferation and was accelerated by metabolic stress conditions. Furthermore, we found C5024T to dysregulate CD8+ T cell metabolic remodeling and IFN-γ production after activation. Together, our data illustrate that the generation of memory lymphocytes shapes the mtDNA landscape, wherein pathogenic variants dysregulate the immune response.
Jingdian Zhang, Camilla Koolmeister, Jinming Han, Roberta Filograna, Leo Hanke, Monika Àdori, Daniel J. Sheward, Sina Teifel, Shreekara Gopalakrishna, Qiuya Shao, Yong Liu, Keying Zhu, Robert A. Harris, Gerald McInerney, Ben Murrell, Mike Aoun, Liselotte Bäckdahl, Rikard Holmdahl, Marcin Pekalski, Anna Wedell, Martin Engvall, Anna Wredenberg, Gunilla B. Karlsson Hedestam, Xaquin Castro Dopico, Joanna Rorbach
Genetic and metabolic changes in tissue and blood are reported to occur several years before glioma diagnosis. As gliomas are currently detected late, a liquid biopsy for early detection could impact the quality of life and prognosis of patients. Here, we present a nested case-control study of 550 pre-diagnostic glioma cases and 550 healthy controls, from the Northern Sweden Health and Disease study (NSHDS) and the European Prospective Investigation into Cancer and Nutrition (EPIC) study. We identified 93 significantly altered metabolites related to glioma development up to eight years before diagnosis. Out of these metabolites, a panel of 20 selected metabolites showed strong disease correlation and consistent progression pattern towards diagnosis in both the NSHDS and EPIC cohorts, and separated favorably future cases from controls independently of biological sex. The blood metabolite panel also successfully separated both lower grade glioma and glioblastoma cases from controls, up to eight years before diagnosis in NSHDS (glioma AUC=0.85, P=3.1e-12; glioblastoma AUC=0.85, P=6.3e-8), and up to two years before diagnosis in EPIC (glioma AUC=0.81, P=0.005; glioblastoma AUC=0.89, P=0.04). Pathway enrichment analysis detected metabolites related to the TCA-cycle, Warburg effect, gluconeogenesis, cysteine-, pyruvate- and tyrosine metabolism as the most affected.
Sebastian Löding, Ulrika Andersson, Rudolf Kaaks, Matthias B. Schulze, Valeria Pala, Ilona Urbarova, Pilar Amiano, Sandra M. Colorado-Yohar, Marcela Guevara, Alicia K. Heath, Anastasia Chrysovalantou Chatziioannou, Mattias Johansson, Lars Nyberg, Henrik Antti, Benny Björkblom, Beatrice Melin
Adipose tissue macrophage (ATM) infiltration is associated with adipose tissue dysfunction and insulin resistance in mice and humans. Recent single cell data highlight increased ATM heterogeneity in obesity, but do not provide a spatial context for ATM phenotype dynamics. We integrated single cell RNA-sequencing, spatial transcriptomics, and imaging of murine adipose tissue in a time course of diet-induced obesity. Overall, proinflammatory immune cells were predominant in early obesity, while non-resident antiinflammatory ATMs predominated in chronic obesity. A subset of these antiinflammatory ATMs were transcriptomically intermediate between monocytes and mature lipid-associated macrophages (LAM) and were consistent with a LAM precursor (pre-LAM). Pre-LAMs were spatially associated with early obesity crown-like structures (CLS), which indicate adipose tissue dysfunction. Spatial data showed colocalization of ligand-receptor transcripts related to lipid signaling among monocytes, pre-LAMs, and LAMs, including Apoe, Lrp1, Lpl and App. Pre-LAM expression of these ligands in early obesity suggested signaling to LAMs in the CLS microenvironment. Our results refine understanding of ATM diversity and provide insight into the dynamics of the LAM lineage during development of metabolic disease.
Cooper M. Stansbury, Gabrielle A. Dotson, Harrison Pugh, Alnawaz Rehemtulla, Indika Rajapakse, Lindsey A. Muir
Pancreatic ductal adenocarcinoma (PDAC) progresses in an organ with a unique pH landscape, where the stroma acidifies after each meal. We hypothesized that disrupting this pH landscape during PDAC progression triggers pancreatic stellate cells (PSCs) and cancer-associated fibroblasts (CAFs) to induce PDAC fibrosis. We revealed that alkaline environmental pH is sufficient to induce PSC differentiation to a myofibroblastic phenotype. We then mechanistically dissected this finding focusing on the involvement of the Na+/H+ exchanger NHE1. Perturbing cellular pH homeostasis by inhibiting NHE1 with cariporide partially alters the myofibroblastic PSC phenotype. To show the relevance of this finding in vivo, we targeted NHE1 in murine PDAC (KPfC). Indeed, tumor fibrosis decreases when mice receive the NHE1-inhibitor cariporide in addition to gemcitabine treatment. Moreover, the tumor immune infiltrate shifts from granulocyte-rich to more lymphocytic. Taken together, our study provides mechanistic evidence on how the pancreatic pH landscape shapes pancreatic cancer through tuning PSC differentiation.
Zoltán Pethő, Karolina Najder, Stephanie Beel, Benedikt Fels, Ilka Neumann, Sandra Schimmelpfennig, Sarah Sargin, Maria Wolters, Klavs Grantins, Eva Wardelmann, Miso Mitkovski, Andrea Oeckinghaus, Albrecht Schwab
Spatially resolved metabolomics enables the investigation of tumoral metabolites in situ. Inter- and intratumor heterogeneity are key factors associated with patient outcomes. Adrenocortical carcinoma (ACC) is an exceedingly rare tumor associated with poor survival. Its clinical prognosis is highly variable, but the contributions of tumor metabolic heterogeneity have not been investigated thus far to our knowledge. An in-depth understanding of tumor heterogeneity requires molecular feature-based identification of tumor subpopulations associated with tumor aggressiveness. Here, using spatial metabolomics by high–mass resolution MALDI Fourier transform ion cyclotron resonance mass spectrometry imaging, we assessed metabolic heterogeneity by de novo discovery of metabolic subpopulations and Simpson’s diversity index. After identification of tumor subpopulations in 72 patients with ACC, we additionally performed a comparison with 25 tissue sections of normal adrenal cortex to identify their common and unique metabolic subpopulations. We observed variability of ACC tumor heterogeneity and correlation of high metabolic heterogeneity with worse clinical outcome. Moreover, we identified tumor subpopulations that served as independent prognostic factors and, furthermore, discovered 4 associated anticancer drug action pathways. Our research may facilitate comprehensive understanding of the biological implications of tumor subpopulations in ACC and showed that metabolic heterogeneity might impact chemotherapy.
Qian Wang, Na Sun, Raphael Meixner, Ronan Le Gleut, Thomas Kunzke, Annette Feuchtinger, Jun Wang, Jian Shen, Stefan Kircher, Ulrich Dischinger, Isabel Weigand, Felix Beuschlein, Martin Fassnacht, Matthias Kroiss, Axel Walch
Alveolar epithelial type II (AEC2) cells strictly regulate lipid metabolism to maintain surfactant synthesis. Loss of AEC2 cell function and surfactant production are implicated in the pathogenesis of the smoking-related lung disease chronic obstructive pulmonary disease (COPD). Whether smoking alters lipid synthesis in AEC2 cells and whether altering lipid metabolism in AEC2 cells contributes to COPD development are unclear. In this study, high-throughput lipidomic analysis revealed increased lipid biosynthesis in AEC2 cells isolated from mice chronically exposed to cigarette smoke (CS). Mice with a targeted deletion of the de novo lipogenesis enzyme, fatty acid synthase (FASN), in AEC2 cells (FasniΔAEC2) exposed to CS exhibited higher bronchoalveolar lavage fluid (BALF) neutrophils, higher BALF protein, and more severe airspace enlargement. FasniΔAEC2 mice exposed to CS had lower levels of key surfactant phospholipids but higher levels of BALF ether phospholipids, sphingomyelins, and polyunsaturated fatty acid–containing phospholipids, as well as increased BALF surface tension. FasniΔAEC2 mice exposed to CS also had higher levels of protective ferroptosis markers in the lung. These data suggest that AEC2 cell FASN modulates the response of the lung to smoke by regulating the composition of the surfactant phospholipidome.
Li-Chao Fan, Keith McConn, Maria Plataki, Sarah Kenny, Niamh C. Williams, Kihwan Kim, Jennifer A. Quirke, Yan Chen, Maor Sauler, Matthias E. Möbius, Kuei-Pin Chung, Estela Area Gomez, Augustine M.K. Choi, Jin-Fu Xu, Suzanne M. Cloonan
Uterine leiomyomas cause heavy menstrual bleeding, anemia, and pregnancy loss in approximately 10 million US women. Driver mutations in the transcriptional mediator complex subunit 12 (MED12) gene in uterine myometrial cells initiate 70% of leiomyoma that grow in a progesterone-dependent manner. We showed a distinct chromatin occupancy landscape of MED12 in mutant (mut)- vs wild-type (wt)-MED12 leiomyoma. Integration of cistromic and transcriptomic data identified tryptophan 2,3-dioxygenase (TDO2) as the top mut-MED12 target gene, which was significantly upregulated in mut-MED12 leiomyoma when compared to adjacent myometrium and wt-MED12 leiomyoma. TDO2 catalyzes the conversion of tryptophan to kynurenine, an aryl hydrocarbon receptor (AHR) ligand that we confirmed to be significantly elevated in mut-MED12 leiomyoma. Treatment of primary mut-MED12 leiomyoma cells with tryptophan or kynurenine stimulated AHR nuclear translocation, increased proliferation, inhibited apoptosis, and induced AHR-target gene expression, whereas blocking the TDO2-kynurenine-AHR pathway by siRNA or pharmacological treatment abolished these effects. Progesterone receptor regulated the expression of AHR and its target genes. In vivo, TDO2 expression positively correlated with the expression of genes crucial for leiomyoma growth. In summary, activation of the TDO2-kynurenine-AHR pathway selectively in mut-MED12 leiomyoma promotes tumor growth and may inform the future development of targeted treatments and precision medicine.
Azna Zuberi, Yongchao Huang, Ariel J. Dotts, Helen Wei, John S. Coon V, Shimeng Liu, Takashi Iizuka, Olivia Wu, Olivia Sotos, Priyanka Saini, Debabrata Chakravarti, Thomas G. Boyer, Yang Dai, Serdar E. Bulun, Ping Yin
Glutaminolysis is a hallmark of the activation and metabolic reprogramming of T cells. Isotopic tracer analyses of antigen-activated effector CD8+ T cells revealed that glutamine is the principal carbon source for the biosynthesis of polyamines putrescine, spermidine and spermine. These metabolites play critical roles in activation-induced T-cell proliferation, as well as for the production of hypusine, which is derived from spermidine and is covalently linked to the translation elongation factor eIF5A. Here, we demonstrated that the glutamine-polyamine-hypusine axis controls the expression of CD69, an important regulator of tissue resident memory T cells (TRM). Inhibition of this circuit augmented the development of TRM cells ex vivo and in vivo in the bone marrow, a well-established niche for TRM cells. Furthermore, blocking the polyamine-hypusine axis augmented CD69 expression and IFN-γ and TNF-α production in human CD8+ T cells from peripheral blood and sarcoma tumor infiltrating lymphocytes, as well as in human CD8+ CAR-T cells. Collectively, these findings support the notion that the polyamine-hypusine circuit can be exploited to modulate TRM cells for therapeutic benefit.
Aya G. Elmarsafawi, Rebecca S. Hesterberg, Mario R. Fernandez, Chunying Yang, Lancia N.F. Darville, Min Liu, John M. Koomen, Otto Phanstiel IV, Reginald Atkins, John E. Mullinax, Shari A. Pilon-Thomas, Frederick L. Locke, Pearlie K. Epling-Burnette, John L. Cleveland
Acyl-CoA thioesterase 1 (ACOT1) catalyzes the hydrolysis of long-chain acyl-CoAs to free fatty acids and coenzyme A and is typically upregulated in obesity. Whether targeting ACOT1 in the setting of high-fat diet induced obesity would be metabolically beneficial is not known. Here we report that male and female ACOT1KO mice are partially protected from high-fat diet induced obesity, an effect associated with increased energy expenditure without alterations in physical activity or food intake. In males, ACOT1 deficiency increased mitochondrial uncoupling protein-2 (UCP2) protein abundance, while reducing 4-hydroxynonenal (4-HNE), a marker of oxidative stress, in white adipose tissue and liver of high-fat fed mice. Moreover, concurrent knockdown of UCP2 with ACOT1 in hepatocytes prevented increases in oxygen consumption observed with ACOT1 knockdown during high lipid loading, suggesting that UCP2-induced uncoupling may increase energy expenditure to attenuate weight gain. Together, these data indicate that targeting ACOT1 may be effective for obesity prevention during caloric excess by increasing energy expenditure.
Timothy D. Heden, Mallory P. Franklin, Christina Dailey, Mara T. Mashek, Chen Chen, Douglas G. Mashek
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