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Cell Reports Sep 2023The cyclic guanosine monophosphate adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) axis plays a vital role in defending foreign pathogens...
The cyclic guanosine monophosphate adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) axis plays a vital role in defending foreign pathogens and maintaining immune homeostasis. While substantial advances have been made in understanding the metabolic changes that occur during macrophage activation, little is known about how these metabolic changes affect the cGAS-STING axis. In this study, we identify that 4-octyl itaconate (4-OI), a derivative of itaconate, inhibits the activation of cGAS-STING. Furthermore, we show that 4-OI inhibits cGAS-STING-related antiviral immune responses and autoimmune inflammation. However, we find that endogenous itaconate does not affect cGAS-STING activation, indicating that 4-OI and itaconate function differently. Mechanistically, we find that 4-OI directly alkylates STING at Cys91, blocking STING palmitoylation and oligomerization. The alkylation of STING by 4-OI represents another type of post-translational modifications (PTMs) of STING. Our findings reveal a mechanism by which cGAS-STING function is regulated through 4-OI alkylation and provide insights into the crosstalk between different kinds of PTMs.
Topics: Lipoylation; Nucleotidyltransferases; Succinates
PubMed: 37624697
DOI: 10.1016/j.celrep.2023.113040 -
Protein & Cell Feb 2024Ubiquitination/ubiquitylation, one of the most fundamental post-translational modifications, regulates almost every critical cellular process in eukaryotes. Emerging... (Review)
Review
Ubiquitination/ubiquitylation, one of the most fundamental post-translational modifications, regulates almost every critical cellular process in eukaryotes. Emerging evidence has shown that essential components of numerous biological processes undergo ubiquitination in mammalian cells upon exposure to diverse stresses, from exogenous factors to cellular reactions, causing a dazzling variety of functional consequences. Various forms of ubiquitin signals generated by ubiquitylation events in specific milieus, known as ubiquitin codes, constitute an intrinsic part of myriad cellular stress responses. These ubiquitination events, leading to proteolytic turnover of the substrates or just switch in functionality, initiate, regulate, or supervise multiple cellular stress-associated responses, supporting adaptation, homeostasis recovery, and survival of the stressed cells. In this review, we attempted to summarize the crucial roles of ubiquitination in response to different environmental and intracellular stresses, while discussing how stresses modulate the ubiquitin system. This review also updates the most recent advances in understanding ubiquitination machinery as well as different stress responses and discusses some important questions that may warrant future investigation.
Topics: Animals; Ubiquitin; Ubiquitination; Protein Processing, Post-Translational; Eukaryota; Homeostasis; Mammals
PubMed: 37470788
DOI: 10.1093/procel/pwad045 -
Nature Jul 2023Hygroscopic biological matter in plants, fungi and bacteria make up a large fraction of Earth's biomass. Although metabolically inert, these water-responsive materials...
Hygroscopic biological matter in plants, fungi and bacteria make up a large fraction of Earth's biomass. Although metabolically inert, these water-responsive materials exchange water with the environment and actuate movement and have inspired technological uses. Despite the variety in chemical composition, hygroscopic biological materials across multiple kingdoms of life exhibit similar mechanical behaviours including changes in size and stiffness with relative humidity. Here we report atomic force microscopy measurements on the hygroscopic spores of a common soil bacterium and develop a theory that captures the observed equilibrium, non-equilibrium and water-responsive mechanical behaviours, finding that these are controlled by the hydration force. Our theory based on the hydration force explains an extreme slowdown of water transport and successfully predicts a strong nonlinear elasticity and a transition in mechanical properties that differs from glassy and poroelastic behaviours. These results indicate that water not only endows biological matter with fluidity but also can-through the hydration force-control macroscopic properties and give rise to a 'hydration solid' with unusual properties. A large fraction of biological matter could belong to this distinct class of solid matter.
Topics: Biological Transport; Fungi; Microscopy, Atomic Force; Water; Wettability; Plants; Bacteria; Spores, Bacterial; Humidity; Elasticity
PubMed: 37286609
DOI: 10.1038/s41586-023-06144-y -
Redox Biology Jul 2023Exercise physiology has gained increasing interest due to its wide effects to promote health. Recent years have seen a growth in this research field also due to the... (Review)
Review
Exercise physiology has gained increasing interest due to its wide effects to promote health. Recent years have seen a growth in this research field also due to the finding of several circulating factors that mediate the effects of exercise. These factors, termed exerkines, are metabolites, growth factors, and cytokines secreted by main metabolic organs during exercise to regulate exercise systemic and tissue-specific effects. The metabolic effects of exerkines have been broadly explored and entail a promising target to modulate beneficial effects of exercise in health and disease. However, exerkines also have broad effects to modulate redox signaling and homeostasis in several cellular processes to improve stress response. Since redox biology is central to exercise physiology, this review summarizes current evidence for the cross-talk between redox biology and exerkines actions. The role of exerkines in redox biology entails a response to oxidative stress-induced pathological cues to improve health outcomes and to modulate exercise adaptations that integrate redox signaling.
Topics: Health Promotion; Oxidation-Reduction; Oxidative Stress; Exercise; Homeostasis
PubMed: 37247469
DOI: 10.1016/j.redox.2023.102748 -
EMBO Reports Feb 2024Tumor cells reprogram nutrient acquisition and metabolic pathways to meet their energetic, biosynthetic, and redox demands. Similarly, metabolic processes in immune... (Review)
Review
Tumor cells reprogram nutrient acquisition and metabolic pathways to meet their energetic, biosynthetic, and redox demands. Similarly, metabolic processes in immune cells support host immunity against cancer and determine differentiation and fate of leukocytes. Thus, metabolic deregulation and imbalance in immune cells within the tumor microenvironment have been reported to drive immune evasion and to compromise therapeutic outcomes. Interestingly, emerging evidence indicates that anti-tumor immunity could modulate tumor heterogeneity, aggressiveness, and metabolic reprogramming, suggesting that immunosurveillance can instruct cancer progression in multiple dimensions. This review summarizes our current understanding of how metabolic crosstalk within tumors affects immunogenicity of tumor cells and promotes cancer progression. Furthermore, we explain how defects in the metabolic cascade can contribute to developing dysfunctional immune responses against cancers and discuss the contribution of immunosurveillance to these defects as a feedback mechanism. Finally, we highlight ongoing clinical trials and new therapeutic strategies targeting cellular metabolism in cancer.
Topics: Humans; Monitoring, Immunologic; Neoplasms; Energy Metabolism; Metabolic Networks and Pathways; Tumor Microenvironment
PubMed: 38216787
DOI: 10.1038/s44319-023-00038-w -
The Journal of Clinical Investigation Dec 2023The functional integrity of Tregs is interwoven with cellular metabolism; however, the mechanisms governing Treg metabolic programs remain elusive. Here, we identified...
The functional integrity of Tregs is interwoven with cellular metabolism; however, the mechanisms governing Treg metabolic programs remain elusive. Here, we identified that the deubiquitinase USP47 inhibited c-Myc translation mediated by the RNA N6-methyladenosine (m6A) reader YTHDF1 to maintain Treg metabolic and functional homeostasis. USP47 positively correlated with the tumor-infiltrating Treg signature in samples from patients with colorectal cancer and gastric cancer. USP47 ablation compromised Treg homeostasis and function in vivo, resulting in the development of inflammatory disorders, and boosted antitumor immune responses. USP47 deficiency in Tregs triggered the accumulation of the c-Myc protein and in turn exacerbated hyperglycolysis. Mechanistically, USP47 prevented YTHDF1 ubiquitination to attenuate the association of YTHDF1 with translation initiation machinery, thereby decreasing m6A-based c-Myc translation efficiency. Our findings reveal that USP47 directs m6A-dependent metabolic programs to orchestrate Treg homeostasis and suggest novel approaches for selective immune modulation in cancer and autoimmune diseases by targeting of USP47.
Topics: Humans; Autoimmune Diseases; Homeostasis; Neoplasms; T-Lymphocytes, Regulatory; Ubiquitination
PubMed: 37788092
DOI: 10.1172/JCI169365 -
The Journal of Biological Chemistry Sep 2023Ferredoxins are a family of iron-sulfur (Fe-S) cluster proteins that serve as essential electron donors in numerous cellular processes that are conserved through...
Ferredoxins are a family of iron-sulfur (Fe-S) cluster proteins that serve as essential electron donors in numerous cellular processes that are conserved through evolution. The promiscuous nature of ferredoxins as electron donors enables them to participate in many metabolic processes including steroid, heme, vitamin D, and Fe-S cluster biosynthesis in different organisms. However, the unique natural function(s) of each of the two human ferredoxins (FDX1 and FDX2) are still poorly characterized. We recently reported that FDX1 is both a crucial regulator of copper ionophore-induced cell death and serves as an upstream regulator of cellular protein lipoylation, a mitochondrial lipid-based post-translational modification naturally occurring on four mitochondrial enzymes that are crucial for TCA cycle function. Here we show that FDX1 directly regulates protein lipoylation by binding the lipoyl synthase (LIAS) enzyme promoting its functional binding to the lipoyl carrier protein GCSH and not through indirect regulation of cellular Fe-S cluster biosynthesis. Metabolite profiling revealed that the predominant cellular metabolic outcome of FDX1 loss of function is manifested through the regulation of the four lipoylation-dependent enzymes ultimately resulting in loss of cellular respiration and sensitivity to mild glucose starvation. Transcriptional profiling established that FDX1 loss-of-function results in the induction of both compensatory metabolism-related genes and the integrated stress response, consistent with our findings that FDX1 loss-of-function is conditionally lethal. Together, our findings establish that FDX1 directly engages with LIAS, promoting its role in cellular protein lipoylation, a process essential in maintaining cell viability under low glucose conditions.
Topics: Humans; Ferredoxins; Lipoylation; Protein Binding; Cell Respiration; Cell Proliferation; Metabolome; Sulfurtransferases
PubMed: 37453661
DOI: 10.1016/j.jbc.2023.105046 -
Nature Metabolism Nov 2023Reversible acetylation of mitochondrial proteins is a regulatory mechanism central to adaptive metabolic responses. Yet, how such functionally relevant protein...
Reversible acetylation of mitochondrial proteins is a regulatory mechanism central to adaptive metabolic responses. Yet, how such functionally relevant protein acetylation is achieved remains unexplored. Here we reveal an unprecedented role of the MYST family lysine acetyltransferase MOF in energy metabolism via mitochondrial protein acetylation. Loss of MOF-KANSL complex members leads to mitochondrial defects including fragmentation, reduced cristae density and impaired mitochondrial electron transport chain complex IV integrity in primary mouse embryonic fibroblasts. We demonstrate COX17, a complex IV assembly factor, as a bona fide acetylation target of MOF. Loss of COX17 or expression of its non-acetylatable mutant phenocopies the mitochondrial defects observed upon MOF depletion. The acetylation-mimetic COX17 rescues these defects and maintains complex IV activity even in the absence of MOF, suggesting an activatory role of mitochondrial electron transport chain protein acetylation. Fibroblasts from patients with MOF syndrome who have intellectual disability also revealed respiratory defects that could be restored by alternative oxidase, acetylation-mimetic COX17 or mitochondrially targeted MOF. Overall, our findings highlight the critical role of MOF-KANSL complex in mitochondrial physiology and provide new insights into MOF syndrome.
Topics: Humans; Animals; Mice; Acetylation; Fibroblasts; Mitochondria; Energy Metabolism; Electron Transport Complex IV; Copper Transport Proteins
PubMed: 37813994
DOI: 10.1038/s42255-023-00904-w -
Immunometabolism (Cobham, Surrey) Jul 2023is a common Gram-negative pathogen associated with community-acquired and healthcare-associated infections. Its ability to acquire genetic elements resulted in its... (Review)
Review
is a common Gram-negative pathogen associated with community-acquired and healthcare-associated infections. Its ability to acquire genetic elements resulted in its rapid development of resistance to virtually all antimicrobial agents. Once infection is established, is able to evade the host immune response and perhaps more importantly, undergo metabolic rewiring to optimize its ability to maintain infection. lipopolysaccharide and capsular polysaccharide are central factors in the induction and evasion of immune clearance. Less well understood is the importance of immunometabolism, the intersection between cellular metabolism and immune function, in the host response to infection. Bacterial metabolism itself is perceived as a metabolic stress to the host, altering the microenvironment at the site of infection. In this review, we will discuss the metabolic responses induced by , particularly in response to stimulation with the metabolically active bacteria versus pathogen-associated molecular patterns alone, and their implications in shaping the nature of the immune response and the infection outcome. A better understanding of the immunometabolic response to may help identify new targets for therapeutic intervention in the treatment of multidrug-resistant bacterial infections.
PubMed: 37492184
DOI: 10.1097/IN9.0000000000000028 -
Adipocyte Dec 2023Adipokines are proteins secreted by adipose tissue to regulate glucolipid metabolism and play vital roles in our body. Different adipokines have more than one endocrine...
Adipokines are proteins secreted by adipose tissue to regulate glucolipid metabolism and play vital roles in our body. Different adipokines have more than one endocrine function and be divided into several different categories according to their functions, including adipokines involved in glucolipid metabolism, the inflammatory response, insulin action, activation of brown adipose tissue (BAT) and appetite regulation. Multiple adipokines interact with each other to regulate metabolic processes. Based on the recent progress of adipokine research, this article discusses the role and mechanism of various adipokines in glucolipid metabolism, which may provide new ideas for understanding the pathogenesis and improving the treatment of various metabolic diseases.
Topics: Adipokines; Glucose; Lipid Metabolism; Adipose Tissue; Adipose Tissue, Brown; Energy Metabolism; Leptin
PubMed: 37077042
DOI: 10.1080/21623945.2023.2202976