bims-imicid 2023-03-26 papers

bims-imicid

Biomed News

on Immunometabolism of infection, cancer and immune-mediated disease

Issue of 2023–03–26
nineteen papers selected by
Dylan Ryan, University of Cambridge

Mitochondrial damage activates the NLRP10 inflammasome.
Epithelial Nlrp10 inflammasome mediates protection against intestinal autoinflammation.
Macrophage metabolic rewiring improves heme-suppressed efferocytosis and tissue damage in sickle cell disease.
The lactate dehydrogenase (LDH) isoenzyme spectrum enables optimally controlling T cell glycolysis and differentiation.
Immunometabolism at the crossroads of obesity and cancer-a Keystone Symposia report.
From rags to riches: Lactate ascension as a pivotal metabolite in neuroenergetics.
Skeletal myotube-derived extracellular vesicles enhance itaconate production and attenuate inflammatory responses of macrophages.
Editorial: Cell stress responses and metabolic reprogramming in skin diseases.
The DNA adenine methylase of Salmonella Enteritidis promotes their intracellular replication by inhibiting arachidonic acid metabolism pathway in macrophages.
GPAT3 regulates the synthesis of lipid intermediate LPA and exacerbates Kupffer cell inflammation mediated by the ERK signaling pathway.
Metabolomic profiling reveals bacterial metabolic adaptation strategies and new metabolites.
Ebola virus-like particles reprogram cellular metabolism.
Overexpression of hypoxia-inducible factor-1α in hidradenitis suppurativa: the link between deviated immunity and metabolism.
Intermittent Fasting induced ketogenesis inhibits mouse epithelial ovarian tumors by promoting anti-tumor T cell response.
Indoleamine 2,3-dioxygenase 1 in circumventing checkpoint inhibitor responses: Updated.
Saturated fatty acids dampen the immunogenicity of cancer by suppressing STING.
Nitric oxide regulates metabolism in murine stress erythroid progenitors to promote recovery during inflammatory anemia.
Faecal metabolome and its determinants in inflammatory bowel disease.
Metabolic reprogramming and flux to cell envelope precursors in a pentose phosphate pathway mutant increases MRSA resistance to β-lactam antibiotics.

Nat Immunol. 2023 Mar 20.

Mitochondrial damage activates the NLRP10 inflammasome.

Tomasz Próchnicki, Matilde B Vasconcelos, Kim S Robinson, Matthew S J Mangan, Dennis De Graaf, Kateryna Shkarina, Marta Lovotti, Lena Standke, Romina Kaiser, Rainer Stahl, Fraser G Duthie, Maximilian Rothe, Kateryna Antonova, Lea-Marie Jenster, Zhi Heng Lau, Sarah Rösing, Nora Mirza, Clarissa Gottschild, Dagmar Wachten, Claudia Günther, Thomas A Kufer, Florian I Schmidt, Franklin L Zhong, Eicke Latz.

Upon detecting pathogens or cell stress, several NOD-like receptors (NLRs) form inflammasome complexes with the adapter ASC and caspase-1, inducing gasdermin D (GSDMD)-dependent cell death and maturation and release of IL-1β and IL-18. The triggers and activation mechanisms of several inflammasome-forming sensors are not well understood. Here we show that mitochondrial damage activates the NLRP10 inflammasome, leading to ASC speck formation and caspase-1-dependent cytokine release. While the AIM2 inflammasome can also sense mitochondrial demise by detecting mitochondrial DNA (mtDNA) in the cytosol, NLRP10 monitors mitochondrial integrity in an mtDNA-independent manner, suggesting the recognition of distinct molecular entities displayed by the damaged organelles. NLRP10 is highly expressed in differentiated human keratinocytes, in which it can also assemble an inflammasome. Our study shows that this inflammasome surveils mitochondrial integrity. These findings might also lead to a better understanding of mitochondria-linked inflammatory diseases.

DOI: https://doi.org/10.1038/s41590-023-01451-y
Nat Immunol. 2023 Mar 20.

Epithelial Nlrp10 inflammasome mediates protection against intestinal autoinflammation.

Danping Zheng, Gayatree Mohapatra, Lara Kern, Yiming He, Merav D Shmueli, Rafael Valdés-Mas, Aleksandra A Kolodziejczyk, Tomasz Próchnicki, Matilde B Vasconcelos, Lena Schorr, Franziska Hertel, Ye Seul Lee, Miguel Camacho Rufino, Emmanuelle Ceddaha, Sandy Shimshy, Ryan James Hodgetts, Mally Dori-Bachash, Christian Kleimeyer, Kim Goldenberg, Melina Heinemann, Noa Stettner, Alon Harmelin, Hagit Shapiro, Jens Puschhof, Minhu Chen, Richard A Flavell, Eicke Latz, Yifat Merbl, Suhaib K Abdeen, Eran Elinav.

Unlike other nucleotide oligomerization domain-like receptors, Nlrp10 lacks a canonical leucine-rich repeat domain, suggesting that it is incapable of signal sensing and inflammasome formation. Here we show that mouse Nlrp10 is expressed in distal colonic intestinal epithelial cells (IECs) and modulated by the intestinal microbiome. In vitro, Nlrp10 forms an Apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC)-dependent, m-3M3FBS-activated, polyinosinic:polycytidylic acid-modulated inflammasome driving interleukin-1β and interleukin-18 secretion. In vivo, Nlrp10 signaling is dispensable during steady state but becomes functional during autoinflammation in antagonizing mucosal damage. Importantly, whole-body or conditional IEC Nlrp10 depletion leads to reduced IEC caspase-1 activation, coupled with enhanced susceptibility to dextran sodium sulfate-induced colitis, mediated by altered inflammatory and healing programs. Collectively, understanding Nlrp10 inflammasome-dependent and independent activity, regulation and possible human relevance might facilitate the development of new innate immune anti-inflammatory interventions.

DOI: https://doi.org/10.1038/s41590-023-01450-z
Blood. 2023 Mar 23. pii: blood.2022018026. [Epub ahead of print]

Macrophage metabolic rewiring improves heme-suppressed efferocytosis and tissue damage in sickle cell disease.

Richa Sharma, Ada Antypiuk, S Zebulon Vance, Deepa Manwani, Quentinn Pearce, James Eric Cox, Xiuli An, Karina Yazdanbakhsh, Francesca Vinchi.

Sickle cell disease (SCD) is hallmarked by an underlying chronic inflammatory condition, which is contributed by heme-activated pro-inflammatory macrophages. While previous studies addressed heme ability to stimulate macrophage inflammatory skewing through TLR4/ROS signaling, how heme alters cell functional properties remains unexplored. Macrophage-mediated immune cell recruitment and apoptotic cell (AC) clearance are relevant in the context of SCD, where tissue damage, cell apoptosis and inflammation occur due to vasoocclusive episodes, hypoxia and ischemic injury. Here we show that heme strongly alters macrophage functional response to AC damage by exacerbating immune cell recruitment and impairing cell efferocytic capacity. In SCD, heme-driven excessive leukocyte influx and defective efferocytosis contribute to exacerbated tissue damage and sustained inflammation. Mechanistically, these events depend on heme-mediated activation of TLR4 signaling and suppression of the transcription factor PPARg and its coactivator PGC1a. These changes reduce efferocytic receptor expression and promote mitochondrial remodeling, resulting in a coordinated functional and metabolic reprogramming of macrophages. Overall, this results in limited AC engulfment, impaired metabolic shift to mitochondrial fatty acid b-oxidation and ultimately reduced secretion of the anti-inflammatory cytokines IL-4 and IL-10, with consequent inhibition of continual efferocytosis, resolution of inflammation and tissue repair. We further demonstrate that impaired phagocytic capacity is recapitulated by macrophage exposure to sickle patients'plasma and improved by hemopexin-mediated heme scavenging, PPARg agonists or IL-4 exposure through functional and metabolic macrophage rewiring. Our data indicate that therapeutic improvement of heme-altered macrophage functional properties via heme scavenging or PGC1a/PPARg modulation significantly ameliorate tissue damage associated with SCD pathophysiology.

DOI: https://doi.org/10.1182/blood.2022018026
Sci Adv. 2023 Mar 24. 9(12): eadd9554

The lactate dehydrogenase (LDH) isoenzyme spectrum enables optimally controlling T cell glycolysis and differentiation.

Xuyong Chen, Lingling Liu, Siwen Kang, Jn Rashida Gnanaprakasam, Ruoning Wang.

Isoenzyme divergence is a prevalent mechanism governing tissue-specific and developmental stage-specific metabolism in mammals. The lactate dehydrogenase (LDH) isoenzyme spectrum reflects the tissue-specific metabolic status. We found that three tetrameric isoenzymes composed of LDHA and LDHB (LDH-3/4/5) comprise the LDH spectrum in T cells. Genetically deleting LDHA or LDHB altered the isoenzyme spectrum by removing all heterotetramers and leaving T cells with LDH-1 (the homotetramer of LDHB) or LDH-5 (the homotetramer of LDHA), respectively. Accordingly, deleting LDHA suppressed glycolysis, cell proliferation, and differentiation. Unexpectedly, deleting LDHB enhanced glycolysis but suppressed T cell differentiation, indicating that an optimal zone of glycolytic activity is required to maintain cell fitness. Mechanistically, the LDH isoenzyme spectrum imposed by LDHA and LDHB is necessary to optimize glycolysis to maintain a balanced nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide hydrogen pool. Our results suggest that the LDH isoenzyme spectrum enables "Goldilocks levels" of glycolytic and redox activity to control T cell differentiation.

DOI: https://doi.org/10.1126/sciadv.add9554
Ann N Y Acad Sci. 2023 Mar 24.

Immunometabolism at the crossroads of obesity and cancer-a Keystone Symposia report.

Jennifer Cable, Jeffrey C Rathmell, Erika L Pearce, Ping-Chih Ho, Marcia C Haigis, Murad R Mamedov, Meng-Ju Wu, Susan M Kaech, Lydia Lynch, Mark A Febbraio, Sagar P Bapat, Hanna S Hong, Weiping Zou, Yasmine Belkaid, Zuri A Sullivan, Andrea Keller, Stefanie K Wculek, Douglas R Green, Catherine Postic, Ido Amit, Salvador Aznar Benitah, Russell G Jones, Miguel Reina-Campos, Santiago Valle Torres, Semir Beyaz, Donal Brennan, Luke A J O'Neill, Rachel J Perry, Dirk Brenner.

  Immunometabolism considers the relationship between metabolism and immunity. Typically, researchers focus on either the metabolic pathways within immune cells that affect their function or the impact of immune cells on systemic metabolism. A more holistic approach that considers both these viewpoints is needed. On September 5-8, 2022, experts in the field of immunometabolism met for the Keystone symposium "Immunometabolism at the Crossroads of Obesity and Cancer" to present recent research across the field of immunometabolism, with the setting of obesity and cancer as an ideal example of the complex interplay between metabolism, immunity, and cancer. Speakers highlighted new insights on the metabolic links between tumor cells and immune cells, with a focus on leveraging unique metabolic vulnerabilities of different cell types in the tumor microenvironment as therapeutic targets and demonstrated the effects of diet, the microbiome, and obesity on immune system function and cancer pathogenesis and therapy. Finally, speakers presented new technologies to interrogate the immune system and uncover novel metabolic pathways important for immunity.

Keywords:  cancer; immunity; immunometabolism; immunotherapy; metabolism; obesity

DOI:  https://doi.org/10.1111/nyas.14976
Front Neurosci. 2023 ;17 1145358

From rags to riches: Lactate ascension as a pivotal metabolite in neuroenergetics.

Avital Schurr.



Keywords:  NADH (NAD+); glucose; glycolysis; lactate; lactate dehydrogenase; mitochondria; oxydative phosphorylation (oxphos); trycarboxylic acid (TCA) cycle

DOI:  https://doi.org/10.3389/fnins.2023.1145358
Front Immunol. 2023 ;14 1099799

Skeletal myotube-derived extracellular vesicles enhance itaconate production and attenuate inflammatory responses of macrophages.

Atomu Yamaguchi, Noriaki Maeshige, Jiawei Yan, Xiaoqi Ma, Mikiko Uemura, Mami Matsuda, Yuya Nishimura, Tomohisa Hasunuma, Hiroyo Kondo, Hidemi Fujino, Zhi-Min Yuan.

   Introduction: Macrophages play an important role in the innate immunity. While macrophage inflammation is necessary for biological defense, it must be appropriately controlled. Extracellular vesicles (EVs) are small vesicles released from all types of cells and play a central role in intercellular communication. Skeletal muscle has been suggested to release anti-inflammatory factors, but the effect of myotube-derived EVs on macrophages is unknown. As an anti-inflammatory mechanism of macrophages, the immune responsive gene 1 (IRG1)-itaconate pathway is essential. In this study, we show that skeletal muscle-derived EVs suppress macrophage inflammatory responses, upregulating the IRG1-itaconate pathway.
Methods: C2C12 myoblasts were differentiated into myotubes and EVs were extracted by ultracentrifugation. Skeletal myotube-derived EVs were administered to mouse bone marrow-derived macrophages, then lipopolysaccharide (LPS) stimulation was performed and inflammatory cytokine expression was measured by RT-qPCR. Metabolite abundance in macrophages after addition of EVs was measured by CE/MS, and IRG1 expression was measured by RT-PCR. Furthermore, RNA-seq analysis was performed on macrophages after EV treatment.
Results: EVs attenuated the expression of LPS-induced pro-inflammatory factors in macrophages. Itaconate abundance and IRG1 expression were significantly increased in the EV-treated group. RNA-seq analysis revealed activation of the PI3K-Akt and JAK-STAT pathways in macrophages after EV treatment. The most abundant miRNA in myotube EVs was miR-206-3p, followed by miR-378a-3p, miR-30d-5p, and miR-21a-5p.
Discussion: Skeletal myotube EVs are supposed to increase the production of itaconate via upregulation of IRG1 expression and exhibited an anti-inflammatory effect in macrophages. This anti-inflammatory effect was suggested to involve the PI3K-Akt and JAK-STAT pathways. The miRNA profiles within EVs implied that miR-206-3p, miR-378a-3p, miR-30d-5p, and miR-21a-5p may be responsible for the anti-inflammatory effects of the EVs. In summary, in this study we showed that myotube-derived EVs prevent macrophage inflammatory responses by activating the IRG1-itaconate pathway.

Keywords:  IRG1; extracellular vesicle; itaconate; macrophage; skeletal muscle

DOI:  https://doi.org/10.3389/fimmu.2023.1099799
Front Cell Dev Biol. 2023 ;11 1171812

Editorial: Cell stress responses and metabolic reprogramming in skin diseases.

Emanuela Bastonini, Daniela Kovacs, Fiorenza Lotti, Luis Sanchez-Del-Campo.



Keywords:  cell metabolism; energetic metabolism; melanoma; metabolic rewiring; phenotype switching; skin diseases

DOI:  https://doi.org/10.3389/fcell.2023.1171812
Front Microbiol. 2023 ;14 1080851

The DNA adenine methylase of Salmonella Enteritidis promotes their intracellular replication by inhibiting arachidonic acid metabolism pathway in macrophages.

Ming Wang, Dan Xiong, Xinwei Wang, Dan Gu, Chuang Meng, Xinan Jiao, Zhiming Pan.

  Macrophages can participate in immune responses by altering their metabolism, and play important roles in controlling bacterial infections. However, Salmonella Enteritidis can survive and proliferate in macrophages. After the deletion of DNA adenine methylase (Dam), the proliferation of Salmonella Enteritidis in macrophages decreased, the molecular mechanism is still unclear. After infecting macrophages with Salmonella Enteritidis wild type and dam gene deletion strains, intracellular metabolites were extracted and detected by non-targeted metabolomics and fatty acid targeted metabolomics. We found Dam had significant effects on arachidonic acid and related metabolic pathways in macrophages. The dam gene can promote the proliferation of Salmonella Enteritidis in macrophages by inhibiting the metabolic pathway of cytosolic phospholipase A2-mediated arachidonic acid production and conversion to prostaglandin E2 in macrophages, reducing the secretion of the pro-inflammatory factors IL-1β and IL-6. In addition, inhibition of arachidonic acid-related pathways in macrophages by Arachidonyl trifluoromethyl ketone could restore the proliferation of dam gene deletion strains in macrophages. This study explored the role of Dam in the process of Salmonella Enteritidis invading host cells from the perspective of host cell metabolism, and provides new insights into the immune escape mechanism of Salmonella Enteritidis.

Keywords:  Salmonella Enteritidis; arachidonic acid; immune escape; intracellular proliferation; metabolomics

DOI:  https://doi.org/10.3389/fmicb.2023.1080851
Cell Death Dis. 2023 Mar 24. 14(3): 208

GPAT3 regulates the synthesis of lipid intermediate LPA and exacerbates Kupffer cell inflammation mediated by the ERK signaling pathway.

Guoqiang Fan, Yanfei Li, Yibo Zong, Xiaoyi Suo, Yimin Jia, Mingming Gao, Xiaojing Yang.

In the process of inflammatory activation, macrophages exhibit lipid metabolism disorders and accumulate lipid droplets. Kupffer cells (KCs) are the resident hepatic macrophage with critical defense functions in the pathogenesis of several types of liver disease. How dysregulated lipid metabolism contributes to perturbed KCs functions remains elusive. Here we report that glycerol-3-phosphate acyltransferase 3 (GPAT3) plays a key role in KCs inflammation response. Our findings indicate that lipopolysaccharide (LPS)-mediated inflammatory activation markedly increased lipid droplets (LDs) accumulation in KCs. This increase could be attributed to significantly up-regulated GPAT3. The loss of GPAT3 function obviously reduced KCs inflammation reaction both in vivo and in vitro, and was accompanied by improved mitochondrial function and decreased production of lysophosphatidic acid (LPA), in turn inhibiting extracellular regulated protein kinases (ERK) signaling pathway. Overall, this study highlights the role of GPAT3 in inflammatory activation of KCs and could thus be a potential therapeutic target for the treatment of inflammation-related liver disease.

DOI: https://doi.org/10.1038/s41419-023-05741-z
Curr Opin Chem Biol. 2023 Mar 20. pii: S1367-5931(23)00025-X. [Epub ahead of print]74 102287

Metabolomic profiling reveals bacterial metabolic adaptation strategies and new metabolites.

Hua Wang, Luiz Pedro S de Carvalho.

  How has metabolomics helped our understanding of infectious diseases? With the threat of antimicrobial resistance to human health around the world, metabolomics has emerged as a powerful tool to comprehensively characterize metabolic pathways to identify new drug targets. However, its output is constrained to known metabolites and their metabolic pathways. Recent advances in instrumentation, methodologies, and computational mass spectrometry have accelerated the use of metabolomics to understand pathogen-host metabolic interactions. This short review discusses a selection of recent publications using metabolomics in infectious/bacterial diseases. These studies unravel the links between metabolic adaptations to environments and host metabolic responses. Moreover, they highlight the importance of enzyme function and metabolite characterization in identifying new drug targets and biomarkers, as well as precision medicine in monitoring therapeutics and diagnosing diseases.

Keywords:  Bacteria; Metabolic adaptation; Metabolites; Metabolomics

DOI:  https://doi.org/10.1016/j.cbpa.2023.102287
J Mol Med (Berl). 2023 Mar 24.

Ebola virus-like particles reprogram cellular metabolism.

Huaqi Tang, Yasmine Abouleila, Anno Saris, Yoshihiro Shimizu, Tom H M Ottenhoff, Alireza Mashaghi.

  Ebola virus can trigger a release of pro-inflammatory cytokines with subsequent vascular leakage and impairment of clotting finally leading to multiorgan failure and shock after entering and infecting patients. Ebola virus is known to directly target endothelial cells and macrophages, even without infecting them, through direct interactions with viral proteins. These interactions affect cellular mechanics and immune processes, which are tightly linked to other key cellular functions such as metabolism. However, research regarding metabolic activity of these cells upon viral exposure remains limited, hampering our understanding of its pathophysiology and progression. Therefore, in the present study, an untargeted cellular metabolomic approach was performed to investigate the metabolic alterations of primary human endothelial cells and M1 and M2 macrophages upon exposure to Ebola virus-like particles (VLP). The results show that Ebola VLP led to metabolic changes among endothelial, M1, and M2 cells. Differential metabolite abundance and perturbed signaling pathway analysis further identified specific metabolic features, mainly in fatty acid-, steroid-, and amino acid-related metabolism pathways for all the three cell types, in a host cell specific manner. Taken together, this work characterized for the first time the metabolic alternations of endothelial cells and two primary human macrophage subtypes after Ebola VLP exposure, and identified the potential metabolites and pathways differentially affected, highlighting the important role of those host cells in disease development and progression. KEY MESSAGES: • Ebola VLP can lead to metabolic alternations in endothelial cells and M1 and M2 macrophages. • Differential abundance of metabolites, mainly including fatty acids and sterol lipids, was observed after Ebola VLP exposure. • Multiple fatty acid-, steroid-, and amino acid-related metabolism pathways were observed perturbed.

Keywords:  Cellular metabolism; Ebola; Endothelial cells; Macrophage polarization

DOI:  https://doi.org/10.1007/s00109-023-02309-4
Arch Dermatol Res. 2023 Mar 24.

Overexpression of hypoxia-inducible factor-1α in hidradenitis suppurativa: the link between deviated immunity and metabolism.

Naglaa Fathi Agamia, Osama Ahmed Sorror, Naglaa Mohamed Sayed, Rasha Abdelmawla Ghazala, Sammar Mohamed Echy, Doaa Helmy Moussa, Bodo Clemens Melnik.

  Hypoxia-inducible factor-1α (HIF-1α) is the master transcription factor of glycolysis, Th17 cell differentiation and suppression of regulatory T cells. In the skin and serum of patients with psoriasis vulgaris, increased expression of HIF-1α has been reported, whereas HIF-1α expression in the skin and serum of patients with hidradenitis suppurativa (HS) has not yet been studied. The objective of the study is to demonstrate is there a role for HIF-1α in the pathogenesis of hidradenitis suppurativa, and its relation to HS severity. Twenty patients suffering from hidradenitis suppurativa were included in the study. Punch biopsies were taken from lesional skin for the determination of HIF-1α expression by immunohistochemical staining, and HIF-1α gene expression by quantitative reverse transcription real time PCR. Quantification of HIF-1α protein concentration was done by enzyme-linked immunosorbent assay. Twenty socio-demographically cross-matched healthy volunteers served as controls. We found increased serum levels of HIF-1α. Literature-derived evidence indicates that the major clinical triggering factors of HS, obesity, and smoking are associated with hypoxia and enhanced HIF-1α expression. Pro-inflammatory cytokines such as tumor necrosis factor-[Formula: see text] via upregulation of nuclear factor [Formula: see text]B enhance HIF-1α expression. HIF-1α plays an important role for keratinocyte proliferation, especially for keratinocytes of the anagen hair follicle, which requires abundant glycolysis providing sufficient precursors molecules for biosynthetic pathways. Metformin via inhibition of mTORC1 as well as adalimumab attenuate HIF-1α expression, the key mediator between Th17-driven deviated immunity and keratinocyte hyperproliferation. In accordance with psoriasis, our study identifies HS as an HIF-1α-driven inflammatory skin disease and offers a new rationale for the prevention and treatment of HS by targeting HIF-1[Formula: see text] overexpression.

Keywords:  Glycolysis; Hidradenitis suppurativa; Hypoxia-inducible factor 1α; Keratinocyte proliferation; Th17 cells

DOI:  https://doi.org/10.1007/s00403-023-02594-6
bioRxiv. 2023 Mar 10. pii: 2023.03.08.531740. [Epub ahead of print]

Intermittent Fasting induced ketogenesis inhibits mouse epithelial ovarian tumors by promoting anti-tumor T cell response.

Mary Priyanka Udumula, Harshit Singh, Rashid Faraz, Laila Poisson, Nivedita Tiwari, Irina Dimitrova, Miriana Hijaz, Radhika Gogoi, Margaret Swenor, Adnan Munkarah, Shailendra Giri, Ramandeep Rattan.

Epithelial Ovarian Cancer (EOC) is the most lethal gynecologic cancer with limited genetic alterations identified that can be therapeutically targeted. In tumor bearing mice, short-term fasting, fasting mimicking diet and calorie restriction enhance the activity of antineoplastic treatment by modulating systemic metabolism and boosting anti-tumor immunity. We tested the outcome of sixteen-hour intermittent fasting (IF) on mouse EOC progression with focus on fasting driven antitumor immune responses. IF resulted in consistent decrease of tumor promoting metabolic growth factors and cytokines, recapitulating changes that creates a tumor antagonizing environment. Immune profiling revealed that IF profoundly reshapes anti-cancer immunity by inducing increase in CD4 + and CD8 + cells, paralleled by enhanced antitumor Th1 and cytotoxic responses, by enhancing their metabolic fitness. Metabolic studies revealed that IF generated bioactive metabolite BHB which can be a potential substitute for simulating the antitumor benefits of IF. However, in a direct comparison, IF surpassed exogenous BHB therapy in improving survival and activating anti-tumor immune response. Thus, our data provides strong evidence for IF and its metabolic mediator BHB for ameliorating EOC progression and as a viable approach in maintaining and sustaining an effective anti-tumor T cell response.

DOI: https://doi.org/10.1101/2023.03.08.531740
Int Immunopharmacol. 2023 Mar 16. pii: S1567-5769(23)00353-3. [Epub ahead of print]118 110032

Indoleamine 2,3-dioxygenase 1 in circumventing checkpoint inhibitor responses: Updated.

Arian Charehjoo, Jamal Majidpoor, Keywan Mortezaee.

  Metabolic alterations occur commonly in tumor cells as a way to adapt available energetic sources for their proliferation, survival and resistance. Indoleamine 2,3-dioxygenase 1 (IDO1) is an intracellular enzyme catalyzing tryptophan degradation into kynurenine. IDO1 expression shows a rise in the stroma of many types of human cancers, and it provides a negative feedback mechanism for cancer evasion from immunosurveillance. Upregulation of IDO1 correlates with cancer aggression, poor prognosis and shortened patient survival. The increased activity of this endogenous checkpoint impairs effector T cell function, increases regulatory T cell (Treg) population and induces immune tolerance, so its inhibition potentiates anti-tumor immune responses and reshapes immunogenic state of tumor microenvironment (TME) presumably through normalizing effector T cell activity. A point is that the expression of this immunoregulatory marker is upregulated after immune checkpoint inhibitor (ICI) therapy, and that it has inducible effect on expression of other checkpoints. These are indicative of the importance of IDO1 as an attractive immunotherapeutic target and rationalizing combination of IDO1 inhibitors with ICI drugs in patients with advanced solid cancers. In this review, we aimed to discuss about the impact of IDO1 on tumor immune ecosystem, and the IDO1-mediated bypass of ICI therapy. The efficacy of IDO1 inhibitor therapy in combination with ICIs in advanced/metastatic solid tumors is also a focus of this paper.

Keywords:  3-dioxygenase 1 (IDO1); Aryl hydrocarbon receptor (AHR); Cytotoxic T lymphocyte associated antigen-4 (CTLA-4); Epacadostat; Immune checkpoint inhibitor (ICI); Indoleamine 2; Programmed death-1 (PD-1); Programmed death-ligand 1 (PD-L1); Tumor microenvironment (TME)

DOI:  https://doi.org/10.1016/j.intimp.2023.110032
Cell Rep. 2023 Mar 22. pii: S2211-1247(23)00314-5. [Epub ahead of print]42(4): 112303

Saturated fatty acids dampen the immunogenicity of cancer by suppressing STING.

Blake R Heath, Wang Gong, Hülya F Taner, Luke Broses, Kohei Okuyama, Wanqing Cheng, Max Jin, Zackary R Fitzsimonds, Andriana Manousidaki, Yuesong Wu, Shaoping Zhang, Haitao Wen, Steven B Chinn, Eric Bartee, Yuying Xie, James J Moon, Yu Leo Lei.

  Oncogenes destabilize STING in epithelial cell-derived cancer cells, such as head and neck squamous cell carcinomas (HNSCCs), to promote immune escape. Despite the abundance of tumor-infiltrating myeloid cells, HNSCC presents notable resistance to STING stimulation. Here, we show how saturated fatty acids in the microenvironment dampen tumor response to STING stimulation. Using single-cell analysis, we found that obesity creates an IFN-I-deprived tumor microenvironment with a massive expansion of suppressive myeloid cell clusters and contraction of effector T cells. Saturated fatty acids, but not unsaturated fatty acids, potently inhibit the STING-IFN-I pathway in HNSCC cells. Myeloid cells from obese mice show dampened responses to STING stimulation and are more suppressive of T cell activation. In agreement, obese hosts exhibited increased tumor burden and lower responsiveness to STING agonist. As a mechanism, saturated fatty acids induce the expression of NLRC3, depletion of which results in a T cell inflamed tumor microenvironment and IFN-I-dependent tumor control.

Keywords:  CP: Cancer; CP: Immunology; NLRC3; STING; head and neck cancer; immunogenicity; innate immunity; metabolism; obesity; saturated fatty acids; type-I interferon

DOI:  https://doi.org/10.1016/j.celrep.2023.112303
bioRxiv. 2023 Mar 11. pii: 2023.03.11.532207. [Epub ahead of print]

Nitric oxide regulates metabolism in murine stress erythroid progenitors to promote recovery during inflammatory anemia.

Baiye Ruan, Yuanting Chen, Sara Trimidal, Imhoi Koo, Fenghua Qian, Jingwei Cai, John Mcguigan, Molly A Hall, Andrew D Patterson, K Sandeep Prabhu, Robert F Paulson.

Inflammation skews bone marrow hematopoiesis increasing the production of myeloid effector cells at the expense of steady-state erythropoiesis. A compensatory stress erythropoiesis response is induced to maintain homeostasis until inflammation is resolved. In contrast to steady-state erythroid progenitors, stress erythroid progenitors (SEPs) utilize signals induced by inflammatory stimuli. However, the mechanistic basis for this is not clear. Here we reveal a nitric oxide (NO)-dependent regulatory network underlying two stages of stress erythropoiesis, namely proliferation, and the transition to differentiation. In the proliferative stage, immature SEPs and cells in the niche increased expression of inducible nitric oxide synthase ( Nos2 or iNOS ) to generate NO. Increased NO rewires SEP metabolism to increase anabolic pathways, which drive the biosynthesis of nucleotides, amino acids and other intermediates needed for cell division. This NO-dependent metabolism promotes cell proliferation while also inhibiting erythroid differentiation leading to the amplification of a large population of non-committed progenitors. The transition of these progenitors to differentiation is mediated by the activation of nuclear factor erythroid 2-related factor 2 (Nfe2l2 or Nrf2). Nrf2 acts as an anti-inflammatory regulator that decreases NO production, which removes the NO-dependent erythroid inhibition and allows for differentiation. These data provide a paradigm for how alterations in metabolism allow inflammatory signals to amplify immature progenitors prior to differentiation.
Key points: Nitric-oxide (NO) dependent signaling favors an anabolic metabolism that promotes proliferation and inhibits differentiation.Activation of Nfe2l2 (Nrf2) decreases NO production allowing erythroid differentiation.

DOI: https://doi.org/10.1101/2023.03.11.532207
Gut. 2023 Mar 23. pii: gutjnl-2022-328048. [Epub ahead of print]

Faecal metabolome and its determinants in inflammatory bowel disease.

Arnau Vich Vila, Shixian Hu, Sergio Andreu-Sánchez, Valerie Collij, Bernadien H Jansen, Hannah E Augustijn, Laura A Bolte, Renate A A A Ruigrok, Galeb Abu-Ali, Cosmas Giallourakis, Jessica Schneider, John Parkinson, Amal Al-Garawi, Alexandra Zhernakova, Ranko Gacesa, Jingyuan Fu, Rinse K Weersma.

   OBJECTIVE: Inflammatory bowel disease (IBD) is a multifactorial immune-mediated inflammatory disease of the intestine, comprising Crohn's disease and ulcerative colitis. By characterising metabolites in faeces, combined with faecal metagenomics, host genetics and clinical characteristics, we aimed to unravel metabolic alterations in IBD.
DESIGN: We measured 1684 different faecal metabolites and 8 short-chain and branched-chain fatty acids in stool samples of 424 patients with IBD and 255 non-IBD controls. Regression analyses were used to compare concentrations of metabolites between cases and controls and determine the relationship between metabolites and each participant's lifestyle, clinical characteristics and gut microbiota composition. Moreover, genome-wide association analysis was conducted on faecal metabolite levels.
RESULTS: We identified over 300 molecules that were differentially abundant in the faeces of patients with IBD. The ratio between a sphingolipid and L-urobilin could discriminate between IBD and non-IBD samples (AUC=0.85). We found changes in the bile acid pool in patients with dysbiotic microbial communities and a strong association between faecal metabolome and gut microbiota. For example, the abundance of Ruminococcus gnavus was positively associated with tryptamine levels. In addition, we found 158 associations between metabolites and dietary patterns, and polymorphisms near NAT2 strongly associated with coffee metabolism.
CONCLUSION: In this large-scale analysis, we identified alterations in the metabolome of patients with IBD that are independent of commonly overlooked confounders such as diet and surgical history. Considering the influence of the microbiome on faecal metabolites, our results pave the way for future interventions targeting intestinal inflammation.

Keywords:  CROHN'S DISEASE; IBD; INTESTINAL MICROBIOLOGY; STOOL MARKERS

DOI:  https://doi.org/10.1136/gutjnl-2022-328048
bioRxiv. 2023 Mar 07. pii: 2023.03.03.530734. [Epub ahead of print]

Metabolic reprogramming and flux to cell envelope precursors in a pentose phosphate pathway mutant increases MRSA resistance to β-lactam antibiotics.

Merve S Zeden, Laura A Gallagher, Emilio Bueno, Aaron C Nolan, Jongsam Ahn, Dhananjay Shinde, Fareha Razvi, Margaret Sladek, Órla Burke, Eoghan O'Neill, Paul D Fey, Felipe Cava, Vinai C Thomas, James P O'Gara.

Central metabolic pathways controls virulence and antibiotic resistance, and constitute potential targets for antibacterial drugs. In Staphylococcus aureus the role of the pentose phosphate pathway (PPP) remains largely unexplored. Mutation of the 6-phosphogluconolactonase gene pgl, which encodes the only non-essential enzyme in the oxidative phase of the PPP, significantly increased MRSA resistance to β-lactam antibiotics, particularly in chemically defined media with glucose, and reduced oxacillin (OX)-induced lysis. Expression of the methicillin-resistance penicillin binding protein 2a and peptidoglycan architecture were unaffected. Carbon tracing and metabolomics revealed extensive metabolic reprogramming in the pgl mutant including increased flux to glycolysis, the TCA cycle, and several cell envelope precursors, which was consistent with increased β-lactam resistance. Morphologically, pgl mutant cells were smaller than wild-type with a thicker cell wall and ruffled surface when grown in OX. Further evidence of the pleiotropic effect of the pgl mutation was reduced resistance to Congo Red, sulfamethoxazole and oxidative stress, and increased resistance to targocil, fosfomycin and vancomycin. Reduced binding of wheat germ agglutinin (WGA) to pgl was indicative of lower wall teichoic acid/lipoteichoic acid levels or altered teichoic acid structures. Mutations in the vraFG or graRS loci reversed the increased OX resistance phenotype and restored WGA binding to wild-type levels. VraFG/GraRS was previously implicated in susceptibility to cationic antimicrobial peptides and vancomycin, and these data reveal a broader role for this multienzyme membrane complex in the export of cell envelope precursors or modifying subunits required for resistance to diverse antimicrobial agents. Altogether our study highlights important roles for the PPP and VraFG/GraRS in β-lactam resistance, which will support efforts to identify new drug targets and reintroduce β-lactams in combination with adjuvants or other antibiotics for infections caused by MRSA and other β-lactam resistant pathogens.
Author summary: High-level resistance to penicillin-type (β-lactam) antibiotics significantly limits the therapeutic options for patients with MRSA infections necessitating the use of newer agents, for which reduced susceptibility has already been described. Here we report for the first time that the central metabolism pentose phosphate pathway controls MRSA resistance to penicillin-type antibiotics. We comprehensively demonstrated that mutation of the PPP gene pgl perturbed metabolism in MRSA leading to increased flux to cell envelope precursors to drive increased antibiotic resistance. Moreover, increased resistance was dependent on the VraRG/GraRS multienzyme membrane complex previously implicated in resistance to antimicrobial peptides and vancomycin. Our data thus provide new insights on MRSA mechanisms of β-lactam resistance, which will support efforts to expand the treatment options for infections caused by this and other antimicrobial resistant pathogens.

DOI: https://doi.org/10.1101/2023.03.03.530734