scholarly journals SLC15A4 mediates M1-prone metabolic shifts in macrophages and guards immune cells from metabolic stress

2021 ◽  
Vol 118 (33) ◽  
pp. e2100295118
Author(s):  
Toshihiko Kobayashi ◽  
Dat Nguyen-Tien ◽  
Yuriko Sorimachi ◽  
Yuki Sugiura ◽  
Takehiro Suzuki ◽  
...  
Keyword(s):  
Amino Acid ◽  
Immune Cells ◽  
Metabolic Regulation ◽  
Inflammatory Responses ◽  
Tricarboxylic Acid Cycle ◽  
Metabolic Stress ◽  
Diaminopimelic Acid ◽  
Metabolic Phenotype ◽  
Interleukin 12 ◽  
Respiratory Homeostasis

The amino acid and oligopeptide transporter Solute carrier family 15 member A4 (SLC15A4), which resides in lysosomes and is preferentially expressed in immune cells, plays critical roles in the pathogenesis of lupus and colitis in murine models. Toll-like receptor (TLR)7/9- and nucleotide-binding oligomerization domain-containing protein 1 (NOD1)-mediated inflammatory responses require SLC15A4 function for regulating the mechanistic target of rapamycin complex 1 (mTORC1) or transporting L-Ala-γ-D-Glu-meso-diaminopimelic acid, IL-12: interleukin-12 (Tri-DAP), respectively. Here, we further investigated the mechanism of how SLC15A4 directs inflammatory responses. Proximity-dependent biotin identification revealed glycolysis as highly enriched gene ontology terms. Fluxome analyses in macrophages indicated that SLC15A4 loss causes insufficient biotransformation of pyruvate to the tricarboxylic acid cycle, while increasing glutaminolysis to the cycle. Furthermore, SLC15A4 was required for M1-prone metabolic change and inflammatory IL-12 cytokine productions after TLR9 stimulation. SLC15A4 could be in close proximity to AMP-activated protein kinase (AMPK) and mTOR, and SLC15A4 deficiency impaired TLR-mediated AMPK activation. Interestingly, SLC15A4-intact but not SLC15A4-deficient macrophages became resistant to fluctuations in environmental nutrient levels by limiting the use of the glutamine source; thus, SLC15A4 was critical for macrophage’s respiratory homeostasis. Our findings reveal a mechanism of metabolic regulation in which an amino acid transporter acts as a gatekeeper that protects immune cells’ ability to acquire an M1-prone metabolic phenotype in inflammatory tissues by mitigating metabolic stress.

scholarly journals OR04-04 Identification of a Novel Transcriptional Regulator of Metabolic Disease in Circulating and Central Myeloid Cells

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
David R Sweet ◽  
Neelakantan T Vasudevan ◽  
Liyan Fan ◽  
Chloe E Booth ◽  
Komal S Keerthy ◽  
...  
Keyword(s):  
Metabolic Disease ◽  
Immune Cells ◽  
Therapeutic Option ◽  
Myeloid Cells ◽  
Metabolic Stress ◽  
Myeloid Cell ◽  
Metabolic Phenotype ◽  
Adipose Tissue Macrophages ◽  
Improved Outcomes ◽  
Peripheral Immune Cells

Abstract Derangement in systemic metabolic homeostasis is tightly associated with widespread activation of resident and circulating immune cells, a phenomenon known as ‘metaflammation’. Numerous studies have explored the role of tissue resident and circulating macrophages in contributing to metaflammation, obesity, and their sequelae; however, there is a dearth of information regarding targetable transcriptional regulators of the genesis and persistence of metabolic disease. Here, we identify myeloid Krüppel-like factor 2 (KLF2) as a novel regulator of metabolic disease. Previous reports demonstrate that KLF2 serves as a critical regulator of myeloid cell quiescence and is downregulated in numerous acute and chronic inflammatory states. Specifically in the context of chronic metaflammation, we note that KLF2 expression is decreased in circulating immune cells of obese patients and in adipose tissue macrophages of high fat diet (HFD) fed mice, which is consistent with the hypothesis that KLF2 regulates metaflammation. To explore this further, we utilized mice with myeloid cell-specific deletion of KLF2 (K2KO) which exhibit accelerated obesity and insulin resistance. K2KO mice have widespread central (i.e. CNS) and peripheral metaflammation both in the basal and HFD-stimulated states. To discern whether the effect of myeloid deletion of KLF2 on metabolism is due to deletion in microglia in the feeding centers of the hypothalamus or in peripheral immune cells, bone marrow chimeras with head shielding were created. 50% reconstitution of circulating immune cells with K2KO cells in wildtype (WT) mice was sufficient to maintain the metabolic disease phenotype, while mice with K2KO microglia + WT circulating cells had only slightly improved outcomes compared to K2KO mice. Conversely, ablation of microglia in K2KO mice using PLX5622 formulated in HFD also successfully attenuated the aberrant feeding behavior, weight gain, and glucose dyshomeostasis seen in K2KO mice. Together, these data demonstrate a role for loss of KLF2 in hematopoietic and CNS resident cells in causing metabolic disease. Given that myeloid KLF2 expression decreases under metabolic stress in WT mice and humans, we sought to explore whether maintenance of KLF2 expression in these cells would be protective against diet-induced metabolic disease. Indeed, mice with myeloid-specific overexpression of KLF2 demonstrated a markedly improved metabolic phenotype when challenged with HFD, providing evidence that targeting KLF2 expression in myeloid cells may prove to be a therapeutic option against metaflammation.

scholarly journals Lysosomal amino acid transporters as key players in inflammatory diseases

2021 ◽  
Author(s):  
Noriko Toyama-Sorimachi ◽  
Toshihiko Kobayashi
Keyword(s):  
Signal Transduction ◽  
Amino Acid ◽  
Immune Cells ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Metabolic Adaptation ◽  
Amino Acid Transporters ◽  
Proof Of Concept ◽  
Immune Mediated ◽  
Solute Carrier

Abstract Controlling inflammation can alleviate immune-mediated, lifestyle-related and neurodegenerative diseases. The endolysosome system plays critical roles in inflammatory responses. Endolysosomes function as signal transduction hubs to convert various environmental danger signals into gene expression, enabling metabolic adaptation of immune cells and efficient orchestration of inflammation. Solute carrier family 15 member 3 (SLC15A3) and member 4 (SLC15A4) are endolysosome-resident amino acid transporters that are preferentially expressed in immune cells. These transporters play essential roles in signal transduction through endolysosomes, and the loss of either transporter can alleviate multiple inflammatory diseases because of perturbed endolysosome-dependent signaling events, including inflammatory and metabolic signaling. Here, we summarize the findings leading to a proof-of-concept for anti-inflammatory strategies based on targeting SLC15 transporters.

scholarly journals Ncl1-mediated metabolic rewiring critical during metabolic stress

2019 ◽  
Vol 2 (4) ◽  
pp. e201900360 ◽  
Author(s):  
Ajay Bhat ◽  
Rahul Chakraborty ◽  
Khushboo Adlakha ◽  
Ganesh Agam ◽  
Kausik Chakraborty ◽  
...  
Keyword(s):  
Amino Acid ◽  
Translational Control ◽  
Acid Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Metabolic Stress ◽  
Protein Translation ◽  
Leucine Supplementation ◽  
Nutritional Limitation ◽  
Amino Acid Levels

Nutritional limitation has been vastly studied; however, there is limited knowledge of how cells maintain homeostasis in excess nutrients. In this study, using yeast as a model system, we show that some amino acids are toxic at higher concentrations. With cysteine as a physiologically relevant example, we delineated the pathways/processes that are altered and those that are involved in survival in the presence of elevated levels of this amino acid. Using proteomics and metabolomics approach, we found that cysteine up-regulates proteins involved in amino acid metabolism, alters amino acid levels, and inhibits protein translation—events that are rescued by leucine supplementation. Through a comprehensive genetic screen, we show that leucine-mediated effect depends on a transfer RNA methyltransferase (NCL1), absence of which decouples transcription and translation in the cell, inhibits the conversion of leucine to ketoisocaproate, and leads to tricarboxylic acid cycle block. We therefore propose a role of NCL1 in regulating metabolic homeostasis through translational control.

scholarly journals Effect of Huangqin Tang on Urine Metabolic Profile in Rats with Ulcerative Colitis Based on UPLC-Q-Exactive Orbitrap MS

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Dunfang Wang ◽  
Xuran Ma ◽  
Shanshan Guo ◽  
Yanli Wang ◽  
Tao Li ◽  
...  
Keyword(s):  
Ulcerative Colitis ◽  
Fatty Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Unsaturated Fatty Acids ◽  
Tricarboxylic Acid Cycle ◽  
Tca Cycle ◽  
Q Exactive ◽  
Therapeutic Mechanisms

As a classic prescription, Huangqin Tang (HQT) has been widely applied to treat ulcerative colitis (UC), although its pharmacological mechanisms are not clear. In this study, urine metabolomics was first analysed to explore the therapeutic mechanisms of HQT in UC rats induced by TNBS. We identified 28 potential biomarkers affected by HQT that might cause changes in urine metabolism in UC rats, mapped the network of metabolic pathways, and revealed how HQT affects metabolism of UC rats. The results showed that UC affects amino acid metabolism and biosynthesis of unsaturated fatty acids and impairs the tricarboxylic acid cycle (TCA cycle). UC induced inflammatory and gastrointestinal reactions by inhibiting the transport of fatty acids and disrupting amino acid metabolism. HQT plays key roles via regulating the level of biomarkers in the metabolism of amino acids, lipids, and so on, normalizing metabolic disorders. In addition, histopathology and other bioinformatics analysis further confirm that HQT altered UC rat physiology and pathology, ultimately affecting metabolic function of UC rats.

scholarly journals TAMI-38. CYSTEINE-PROMOTING COMPOUNDS INDUCE MITOCHONDRIAL TOXICITY IN GLIOBLASTOMA THROUGH ALTERED PYRUVATE AND SERINE METABOLISM

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii221-ii221
Author(s):  
Evan Noch ◽  
Laura Palma ◽  
Isaiah Yim ◽  
Bhavneet Binder ◽  
Elisa Benedetti ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Growth ◽  
Growth Inhibition ◽  
Glucose Deprivation ◽  
Tumor Metabolism ◽  
Metabolic Phenotype ◽  
Low Grade ◽  
Mitochondrial Toxicity ◽  
Human Cancers ◽  
Pathway Gene

Abstract Glioblastoma (GBM) remains a poorly treatable disease with high mortality. Tumor metabolism in GBM is a critical mechanism responsible for accelerated growth because of upregulation of glucose, amino acid, and fatty acid utilization. However, little is known about the metabolic alterations that are specific to GBM and that are targetable with FDA-approved compounds. To investigate tumor metabolism signatures unique to GBM, we interrogated the TCGA and a cancer metabolite database for alterations in glucose and amino acid signatures in GBM relative to other human cancers and relative to low-grade glioma. From these analyses, we found that GBM exhibits the highest levels of cysteine and methionine pathway gene expression of 32 human cancers and that GBM exhibits high levels of cysteine-related metabolites compared to low-grade gliomas. To study the role of cysteine in GBM pathogenesis, we treated patient-derived GBM cells with a variety of FDA-approved cyst(e)ine-promoting compounds in vitro, including N-acetylcysteine (NAC) and the cephalosporin antibiotic, Ceftriaxone (CTX), which induces cystine import through System Xc transporter upregulation. Cysteine-promoting compounds, including NAC and CTX, inhibit growth of GBM cells, which is exacerbated by glucose deprivation. This growth inhibition is associated with reduced mitochondrial metabolism, manifest by reduction in ATP, NADPH/NADP+ ratio, mitochondrial membrane potential, and oxygen consumption rate. Metabolic tracing experiments with 13C6-glucose demonstrate that L-serine is rapidly depleted in GBM cells upon treatment with NAC and CTX, and exogenous serine rescues NAC- and CTX-mediated cell growth inhibition. In addition, these compounds reduce GBM mitochondrial pyruvate transport. We show that cysteine-promoting compounds reduce cell growth and induce mitochondrial toxicity in GBM, which may be due to rapid serine depletion and reduced mitochondrial pyruvate transport. This metabolic phenotype is exacerbated by glucose deprivation. This pathway is targetable with FDA-approved cysteine-promoting compounds and could synergize with glucose-lowering treatments, including the ketogenic diet, for GBM.

scholarly journals Cost-Effective Real-Time Metabolic Profiling of Cancer Cell Lines for Plate-Based Assays

Chemosensors ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 139
Author(s):  
Wiktoria Blaszczak ◽  
Zhengchu Tan ◽  
Pawel Swietach
Keyword(s):  
Real Time ◽  
Cell Lines ◽  
Acid Production ◽  
Metabolic Regulation ◽  
Cost Effective ◽  
Culture Conditions ◽  
Metabolic Inhibitors ◽  
Metabolic Phenotype ◽  
Ductal Adenocarcinoma ◽  
Oxygen Utilization

A fundamental phenotype of cancer cells is their metabolic profile, which is routinely described in terms of glycolytic and respiratory rates. Various devices and protocols have been designed to quantify glycolysis and respiration from the rates of acid production and oxygen utilization, respectively, but many of these approaches have limitations, including concerns about their cost-ineffectiveness, inadequate normalization procedures, or short probing time-frames. As a result, many methods for measuring metabolism are incompatible with cell culture conditions, particularly in the context of high-throughput applications. Here, we present a simple plate-based approach for real-time measurements of acid production and oxygen depletion under typical culture conditions that enable metabolic monitoring for extended periods of time. Using this approach, it is possible to calculate metabolic fluxes and, uniquely, describe the system at steady-state. By controlling the conditions with respect to pH buffering, O2 diffusion, medium volume, and cell numbers, our workflow can accurately describe the metabolic phenotype of cells in terms of molar fluxes. This direct measure of glycolysis and respiration is conducive for between-runs and even between-laboratory comparisons. To illustrate the utility of this approach, we characterize the phenotype of pancreatic ductal adenocarcinoma cell lines and measure their response to a switch of metabolic substrate and the presence of metabolic inhibitors. In summary, the method can deliver a robust appraisal of metabolism in cell lines, with applications in drug screening and in quantitative studies of metabolic regulation.

scholarly journals Exploring the Multimodal Role of Yucca schidigera Extract in Protection against Chronic Ammonia Exposure Targeting: Growth, Metabolic, Stress and Inflammatory Responses in Nile Tilapia (Oreochromis niloticus L.)

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 2072
Author(s):  
Zizy I. Elbialy ◽  
Abdallah S. Salah ◽  
Ahmed Elsheshtawy ◽  
Merna Rizk ◽  
Muyassar H. Abualreesh ◽  
...  
Keyword(s):  
Nile Tilapia ◽  
Inflammatory Responses ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Metabolic Stress ◽  
Fish Growth ◽  
Control Group ◽  
Feed Conversion ◽  
Final Body Weight ◽  
Yucca Schidigera

Ammonia is a critical hazardous nitrogen metabolic product in aquaculture. Despite trials for its control, ammonia intoxication remains one of the most critical issues to overcome. In this study, we explored the modulatory effect and potential mechanism by which Yucca schidigera extract (YSE) can ameliorate ammonia intoxication-induced adverse effects on tilapia health and metabolism. A total number of 120 Nile tilapia were evenly assigned into four groups with three replicates each. The first group served as normal control group; the second group was exposed to ammonia alone from the beginning of the experiment and for four weeks. The third group was supplied with YSE in water at a dose of 8 mg/L and exposed to ammonia. The fourth group was supplied with YSE only in water at a dose of 8 mg/L. YSE supplementation succeeded in improving water quality by reducing pH and ammonia levels. Moreover, YSE supplementation markedly alleviated chronic ammonia-induced adverse impacts on fish growth by increasing the final body weight (FBW), specific growth rate (SGR), feed intake and protein efficiency ratio (PER) while reducing the feed conversion ratio (FCR) via improvements in food intake, elevation of hepatic insulin-like growth factor (ILGF-1) and suppression of myostatin (MSTN) expression levels with the restoration of lipid reserves and the activation of lipogenic potential in adipose tissue as demonstrated by changes in the circulating metabolite levels. In addition, the levels of hepato-renal injury biomarkers were restored, hepatic lipid peroxidation was inhibited and the levels of hepatic antioxidant biomarkers were enhanced. Therefore, the current study suggests that YSE supplementation exerted an ameliorative role against chronic ammonia-induced oxidative stress and toxic effects due to its free radical-scavenging potential, potent antioxidant activities and anti-inflammatory effects.

scholarly journals Toxoplasma gondii Cyclophilin 18-Mediated Production of Nitric Oxide Induces Bradyzoite Conversion in a CCR5-Dependent Manner

2009 ◽  
Vol 77 (9) ◽  
pp. 3686-3695 ◽  
Author(s):  
Hany M. Ibrahim ◽  
Hiroshi Bannai ◽  
Xuenan Xuan ◽  
Yoshifumi Nishikawa
Keyword(s):  
Nitric Oxide ◽  
Toxoplasma Gondii ◽  
Inflammatory Responses ◽  
Interleukin 12 ◽  
Dependent Manner ◽  
Independent Manner ◽  
Necrosis Factor Alpha ◽  
Parasite Multiplication ◽  
Factor Alpha

ABSTRACT Toxoplasma gondii modulates pro- and anti-inflammatory responses to regulate parasite multiplication and host survival. Pressure from the immune response causes the conversion of tachyzoites into slowly dividing bradyzoites. The regulatory mechanisms involved in this switch are poorly understood. The aim of this study was to investigate the immunomodulatory role of T. gondii cyclophilin 18 (TgCyp18) in macrophages and the consequences of the cellular responses on the conversion machinery. Recombinant TgCyp18 induced the production of nitric oxide (NO), interleukin-12 (IL-12), and tumor necrosis factor alpha through its binding with cysteine-cysteine chemokine receptor 5 (CCR5) and the production of gamma interferon and IL-6 in a CCR5-independent manner. Interestingly, the treatment of macrophages with TgCyp18 resulted in the inhibition of parasite growth and an enhancement of the conversion into bradyzoites via NO in a CCR5-dependent manner. In conclusion, T. gondii possesses sophisticated mechanisms to manipulate host cell responses in a TgCyp18-mediated process.

scholarly journals Host and Bacterial Factors Contributing to the Clearance of Colonization by Streptococcus pneumoniae in a Murine Model

2005 ◽  
Vol 73 (11) ◽  
pp. 7718-7726 ◽  
Author(s):  
Annemarie M. C. van Rossum ◽  
Elena S. Lysenko ◽  
Jeffrey N. Weiser
Keyword(s):  
Streptococcus Pneumoniae ◽  
Time Course ◽  
Inflammatory Responses ◽  
Adaptive Immune Response ◽  
Interleukin 12 ◽  
Cell Mediated Immunity ◽  
T Helper 1 ◽  
Independent Manner ◽  
Immunodeficient Mice ◽  
Human Host Factors

ABSTRACT Nasopharyngeal colonization is the first step in the interaction between Streptococcus pneumoniae (the pneumococcus) and its human host. Factors that contribute to clearance of colonization are likely to affect the spread of the pneumococcus and the rate of pneumococcal disease in the population. To identify host and bacterial factors contributing to this process, we examined the time course of colonization using genetically modified mice and pneumococci. Severe combined immunodeficient mice remained persistently colonized (>6 weeks). Major histocompatibility complex II-deficient mice, but not μMT mice, were unable to clear colonization and showed a diminished T helper 1 response. Thus, CD4+ T cells, rather than the generation of specific antibody, appear to be required for effective Th1-mediated clearance. In addition, the microbial pattern recognition receptor toll-like receptor 2 (TLR2), but not TLR4, was necessary for efficient clearance of colonization. In contrast, no role of complement component 3, inducible nitric oxide synthetase, interleukin 12 (IL-12), or IL-4 could be demonstrated. Expression of the pneumococcal toxin pneumolysin enhanced acute localized inflammatory responses and promoted clearance of colonization in a TLR4-independent manner. We conclude that both innate and CD4+ T-cell-mediated immunity and proinflammatory bacterial factors, rather than a humoral adaptive immune response, are important for clearance of S. pneumoniae from the murine nasopharynx.

Sign in / Sign up

Export Citation Format

Share Document