Metabolism
Abstract
Purine metabolism dysregulation has been implicated in Alzheimer’s disease (AD), but its temporal dynamics and mechanistic links to core pathologies remain unclear. This translational study integrated a longitudinal preclinical AD mouse model and clinical cohort investigations to define the role of purine metabolism in AD progression. In APPswe/PSEN1dE9 (APP/PS1) mice, serum-untargeted metabolomics identified purine metabolism as the most notably altered pathway, with metabolite levels (e.g., adenine, adenosine) shifting dynamically across disease stages alongside increasing amyloid-β (Aβ) burden. In the pathology-defined clinical cohort, targeted analysis revealed that serum uric acid and allantoin were specifically depleted in the Aβ+ cognitively impaired (CI) group and correlated strongly with higher brain Aβ load, increased neuroinflammation, and poorer cognitive scores. Formal mediation analysis elucidated a plausible mechanistic cascade: the association of uric acid/allantoin with cognitive impairment was primarily mediated by Aβ pathology. Two-year longitudinal data further suggest that changes in specific purine metabolites might predict the rate of cognitive decline. Allantoin supplementation reduced Aβ pathology through promoting microglial phagocytosis of Aβ in APP/PS1 mice. Our findings identified purine metabolism as a key hub connecting Aβ pathology, neuroinflammation, and clinical progression in AD.
Authors
Xiaohang Qian, Zhongxuan Wang, Siyue Chen, Yang Xue, Yawen Yang, Peijing Cui, Miao Zhang, Huidong Tang
Abstract
Matrix stiffness is a hallmark of aggressive solid tumors and strongly associated with therapeutic resistance and poor prognosis. This mechanical barrier represents a major unmet challenge in oncology, as current strategies rarely address how matrix mechanics themselves drive treatment resistance. Here, we identified ferroptosis, an iron-dependent form of cell death, as a potential long-sought vulnerability that can be exploited to eliminate mechanically resistant tumors. Using genetic and chemical approaches, we investigated how matrix stiffness sensitizes cancer cells to ferroptosis and whether this vulnerability can be therapeutically targeted. We found that cancer cells cultured on stiff matrices were more sensitive to ferroptosis than those on soft matrices, as evidenced by reduced cell viability and elevated lipid peroxidation. Furthermore, we found that matrix stiffness induced YAP activation, which upregulated its target gene SKP2, a key mediator required for the heightened ferroptosis sensitivity observed under stiff conditions. Finally, using an injectable hydrogel system, we demonstrated that stiffened tumors were resistant to chemotherapy but remained highly susceptible to ferroptosis induction, resulting in markedly reduced tumor volume and weight. Our findings established ferroptosis as a stiffness-dependent vulnerability mediated by a YAP-SKP2 signaling axis, revealing a mechanotransductive pathway that may be leveraged to target treatment-refractory tumors.
Authors
Emma Villares, Nico Taber, Shao-Chin Wu, Connor Amelung, Jianli Wu, Chao-Chieh Lin, Jen-Tsan Chi, Sharon Gerecht
Abstract
Obesity is a chronic progressive disease strongly linked to numerous comorbidities. This is underpinned by a chronic inflammatory environment and significant immune dysregulation. γδ T cells are unconventional T cells that display innate and adaptive characteristics, the predominant one being their independence of MHC restriction. In humans, γδ T cells represent up to 5% of the peripheral blood T cell compartment and are capable of rapidly producing a range of effector cytokines and driving cytotoxic responses. This is critical for protection from both bacterial and viral infections. We investigated circulating γδ T cell metabolic and functional responses in cohorts of people living with obesity (PWO) and people without obesity. We showed that PWO have reduced Vδ2+ T cell frequencies, and their effector responses are diminished following stimulation. We identified that the CD98-LAMTOR5-mTORC1 metabolic axis was critical for functional responses, and demonstrated significant defects in each component of this axis in PWO. Furthermore, STAT5 the initiator of amino acid metabolism was also decreased in PWO. Finally, we showed restoration of this metabolic axis after bariatric surgery, combined with robust improvements in functional responses. Collectively, our data highlighted that obesity drives a reversible dysregulation of Vδ2+ T cells by disrupting cellular metabolism.
Authors
Ciara L. Flynn, Eimear K. Ryan, Cian Davis, Czara A. Kennedy, Katherine G. Egan, Aimee Brennan, Philip Mc Entee, Kirstan Murphy, Niamh Lynam-Lennon, Linda V. Sinclair, Nicholas Jones, Donal O'Shea, Helen M. Heneghan, Andrew E. Hogan
Abstract
Exposure of humans to food insecurity (FI), involving sporadic access and low nutritional quality, is associated with later life development of metabolic disease phenotypes, but mechanisms are poorly understood. We exposed very young rats to a 20-day FI intervention or ad-lib (AL) feeding, using either standard chow (SC) or high fat/high sucrose (HF/HS) diets, followed by continued AL feeding on the respective diets for 10-13 weeks. We found that male, but not female rats subjected to FI on the HF/HS diet had increased body fat percentage, ratio of adipose to body weight, and fat cell size compared to AL rats, coupled with metabolomic and transcriptomic profiles consistent with reduced fatty acid oxidation in the liver and maladaptive remodeling of adipose tissue. These changes were specific to HF/HS feeding and did not occur with SC diet. Our study defines sex- and diet-specific metabolic remodeling responses to FI that may contribute to future disease phenotypes.
Authors
Jie An, Jessica Cannavino, Ashley Williams, Akshay Bareja, Wenxin Tong, Olga Ilkayeva, Michael Muehlbauer, Danhong Lu, Robert A. Hollander, Sarah Armstrong, Rana K. Gupta, Christopher B. Newgard
Abstract
The hypothesized cellular and molecular mechanisms underlying dystonia are broad and include mutations that perturb Ca2+ signaling, including those affecting voltage gated calcium channels (VGCC). In mice, pharmacological activation of neuronal L-type VGCCs induces dystonia in a dose dependent manner. Here we demonstrate that mice expressing a gain-of-function mutation in the L-type VGCC CaV1.2, associated with Timothy syndrome (TS), exhibit motor dysfunction consistent with dystonia. Although CaV1.2 is broadly expressed throughout peripheral tissues and across the brain, we establish that the dystonia-like behavior is driven by neuronal expression of the mutant calcium channel and observe an associated potential excitatory/inhibitory (E/I) imbalance. Because patients with TS have profound metabolic dysregulation, which is associated with some dystonias, we measured changes in circulating metabolites. The dystonia-like events are sensitive to perturbations in pyruvate metabolism, reminiscent of a subset of dystonias associated with pyruvate dysregulation. Our study provides insight into the potential convergence of previously established causes of dystonia, calcium signaling and metabolic homeostasis.
Authors
Patrick Towers, Hong-Gang Wang, Maiko Matsui, Geoffrey S. Pitt
Abstract
Pneumocystis jirovecii pneumonia (PCP) remains a major cause of life-threatening respiratory failure in people with advanced HIV, yet the biological factors associated with mortality are incompletely understood. We performed integrated transcriptomic, proteomic, and metabolomic profiling of bronchoalveolar lavage fluid from 42 adults with HIV-associated PCP, relating molecular signatures to mortality. We found that fungal burden, measured by sputum immunofluorescence, Pneumocystis qPCR, and 1,3-β-D-glucan, did not differ between survivors and non-survivors or correlate with baseline gas exchange. Instead, non-survivors exhibited a bronchoalveolar immunometabolic failure signature characterised by marked depletion of immunoglobulins and complement, reduced pattern recognition receptors and fibroblast growth factor family proteins, and broad disruption of extracellular matrix organisation. Metabolomic profiling revealed enrichment of arginine-urea cycle and tricarboxylic acid pathways, with coordinated accumulation of arginine, citrulline, and TCA cycle intermediates consistent with nitrosative and mitochondrial stress. An integrated proteo-metabolomic score summarising this state was significantly higher in non-survivors and did not correlate with fungal burden or cytomegalovirus co-infection. In an immunodeficient precision-cut lung slice model, antigen-screened intravenous immunoglobulin restored macrophage-mediated Pneumocystis clearance, providing proof-of-concept for opsonic augmentation. Our findings indicate that mortality in HIV-PCP is defined by profound immunometabolic failure, highlighting humoral depletion and impaired alveolar repair as potential targets for host-directed adjunctive therapy.
Authors
Peter Rossi-Smith, Ayanda Trevor Mnguni, Dora Pungan, Robert J. Samuels, Vaishnavi R. Kumaran, Leena Syed, Trevor Ferris, Kamil Skirlo, Joseph N. Jarvis, Nelesh P. Govender, Graeme Meintjes, Sean Wasserman, Jay K. Kolls, Rachel P.J. Lai
Abstract
The hypothalamic-pituitary-adrenal (HPA) axis integrates central neural processing and responses to stress with endocrine and metabolic responses. We utilized a monoclonal antibody binding corticotrophin-releasing factor (anti-CRF) to achieve durable HPA axis modulation. In mice, anti-CRF treatment decreased plasma corticosterone, food-intake, body weight and fat mass, but preserved lean mass and improved metabolic parameters including insulin sensitization. These body composition effects were observed in middle aged mice on normal chow or high fat diet, aged mice, and Mc4r-/- and ob/ob mice. Single-dose studies demonstrated impacts on weight gain and body composition lasting beyond the period of pharmacological target engagement. Multi-organ transcriptomic and proteomic analyses revealed organ-specific effects of anti-CRF and are consistent with altered glucocorticoid receptor (GR) signaling as a mediator of the observed phenotypes. These studies support anti-CRF-mediated HPA-axis modulation as a metabolic and anti-obesity therapeutic approach distinct from incretins.
Authors
Zachary A. Krumm, Tariful Islam, Caroline M. Watson, Yong Ran, Yona Levites, Hunter S. Futch, Luming Yin, Edgardo Rodriguez-Lebron, Xuefei Liu, Kazi Farhana Afroz, Ariella Goloborodsky, Thomas B. Ladd, Kristy D. Dillon, Danny Ryu, Jennifer L. Bizon, Jada Lewis, Karen A. Scott, Annette de Kloet, Nicholas T. Seyfried, Eric G. Krause, Karen N. McFarland, Todd E. Golde
Abstract
BACKGROUND Dichloroacetate (DCA) is an orally administered structural analog of pyruvate, an endogenous pyruvate dehydrogenase kinase inhibitor.METHODS We conducted a phase III multicenter trial in 34 children with pyruvate dehydrogenase complex deficiency (PDCD). Participants were randomly allocated to 4 months of treatment with DCA or a placebo, followed by a 1-month washout period and crossover to the alternate arm, and could continue into an open-label extension period. DCA dosing was predetermined by pharmacogenomic analysis of GSTZ1, which modulates DCA metabolism. The primary endpoint was the observer-reported outcomes motor domain (ObsROmotor) score. Additional assessments evaluated motor function, plasma lactate levels, and survival.RESULTS Chronic DCA was well tolerated and safe. The primary endpoint, ObsROmotor, was not statistically significantly different between the treatment and placebo groups (P = 0.512). However, longer-term treatment, including the open-label extension, showed a statistically significant treatment effect (P = 0.002), especially in participants with higher baseline motor impairment (ObsROmotor ≥ 8; P = 0.001). DCA decreased plasma lactate –0.48 (0.82) mmol/L (–20%; P = 0.006). Survival of participants was significantly greater than that of a natural history cohort (log-rank P = 0.027).CONCLUSION Longer-term treatment with DCA, dosed based on GSTZ1 haplotype, is safe and was associated with a statistically significant improvement in patient motor function, plasma lactate, and survival.FUNDING NIH (R01FD005407; R42HD089804), University of Florida Department of Medicine, Saol Therapeutics.
Authors
Peter W. Stacpoole, Jose E. Abdenur, Jirair K. Bedoyan, Lorenzo Botto, Gregory M. Enns, Marni J. Falk, Rebecca Ganetzky, Cheryl Garganta, Kevin Glinton, Andrea Gropman, Sharon Hamm, Eugenia Henry, Nicola Longo, Richard Neiberger, Russell P. Saneto, Fernando Scaglia, Sub H. Subramony, Jerry Vockley, Richard E. Wagner
Mitochonic acid 5 alleviates amyotrophic lateral sclerosis phenotypes via mitochondrial augmentation
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that urgently requires effective treatment. Mitochondrial dysfunction underlies ALS pathology and represents a potential therapeutic target. Here, we demonstrated the therapeutic potential of mitochonic acid 5 (MA-5), a novel mitochondria-targeted compound that ameliorated ALS phenotypes by enhancing mitochondrial function. In a Drosophila ALS model expressing a mutant human SOD1 (G85R), MA-5 significantly improved locomotor activity, with a trend toward restoration of mitochondrial integrity. In skin fibroblasts derived from ALS patients and motor neurons derived from induced pluripotent stem cells, MA-5 restored ATP production and increased mitochondrial motility. Multiomics analyses suggested that MA-5 modulated mitochondria-linked gene expression and downregulated the glycerophosphate shuttle, contributing to mitochondrial reactive oxygen species production. Transcriptomic analysis identified C7orf31 as a potential marker for monitoring the therapeutic effects of MA-5 and diagnosing ALS subtypes. These findings support MA-5 as a promising therapeutic candidate for ALS and propose C7orf31 as a potential biomarker for treatment monitoring and for disease subtyping.
Authors
Yoshitsugu Oikawa, Yuhan Luo, Naoki Suzuki, Tomoko Kasahara, Yoshiyasu Tongu, Yuki Yoshida, Tsukasa Tominari, Shogo Tanabe, Yoshiko Suto, Hitomi Kashiwagi, Saki Saito, Kensuke Ikeda, Chitose Suzuki, Arata Kuranaga, Tetsuya Akiyama, Satoru Morimoto, Yoshitsugu Aoki, Rieko Muramatsu, Tomoyoshi Soga, Masashi Aoki, Hideyuki Okano, Tetsuhiro Tanaka, Takaaki Abe, Erina Kuranaga, Takafumi Toyohara
Abstract
Foxp3 deficiency causes a profound loss of immune tolerance, unleashing autoreactive T and B cells, lymphoproliferation, cytokine-driven inflammation, and autoantibody production. This autoimmune pathology is fueled by increased glutamine usage, but it remains unresolved whether glutamine is necessary to produce energy or for intermediate metabolite biosynthesis responsible for immunomodulation. Here, we demonstrate that glutamine utilization for biosynthetic pathways supported autoimmune inflammation in the settings of Foxp3 deficiency and dextran sodium sulfate–induced colitis. By employing a model of autoimmunity driven by Treg-specific loss of Foxp3, we showed that this effect is independent of pathogenic Foxp3-deficient Treg reprogramming. Mechanistically, glutamine biosynthetic pathways sustained conventional T cell activation and proinflammatory cytokine production by preventing inosine accumulation and signaling, thus implicating adenosine pathway modulation in autoreactive T cell dysregulation. Conversely, autoreactive B cell activation and autoantibody production relied on glutamine-dependent asparagine availability, which we identified as a targetable vulnerability for autoantibody formation. These findings highlighted glutamine-driven biosynthetic processes as critical drivers of autoimmunity and revealed distinct metabolic vulnerabilities in autoreactive T and B cells that could be targeted for therapeutic intervention.
Authors
Mohammad Adeel Zafar, Charlotte N. Hill Machado, Jyotirmaya Behera, Yuelin Zhong, Xiao Li, Shakchhi Joshi, Yassine El Fazaa, Virginia Camacho, Peter Georgiev, Kiran Kurmi, Marcia Haigis, Louis-Marie Charbonnier
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