scholarly journals Immunometabolism orchestrates training of innate immunity in atherosclerosis

2019 ◽  
Vol 115 (9) ◽  
pp. 1416-1424 ◽  
Author(s):  
Julia van Tuijl ◽  
Leo A B Joosten ◽  
Mihai G Netea ◽  
Siroon Bekkering ◽  
Niels P Riksen
Keyword(s):  
Cell Activation ◽  
Cholesterol Metabolism ◽  
Myeloid Cell ◽  
Metabolic Reprogramming ◽  
Immune Memory ◽  
Low Grade ◽  
Trained Immunity ◽  
Monocytes And Macrophages

Abstract Atherosclerosis is characterized by a persistent, low-grade inflammation of the arterial wall. Monocytes and monocyte-derived macrophages play a pivotal role in the various stages of atherosclerosis. In the past few years, metabolic reprogramming has been identified as an important controller of myeloid cell activation status. In addition, metabolic and epigenetic reprogramming are key regulatory mechanisms of trained immunity, which denotes the non-specific innate immune memory that can develop after brief stimulation of monocytes with microbial or non-microbial stimuli. In this review, we build the case that metabolic reprogramming of monocytes and macrophages, and trained immunity in particular, contribute to the pathophysiology of atherosclerosis. We discuss the specific metabolic adaptations, including changes in glycolysis, oxidative phosphorylation, and cholesterol metabolism, that have been reported in atherogenic milieus in vitro and in vivo. In addition, we will focus on the role of these metabolic pathways in the development of trained immunity.

scholarly journals Membrane-associated and secreted forms of the Rhesus macaque rhadinovirus-encoded CD200 homologue and cellular CD200 demonstrate differential effects on Rhesus Macaque CD200 Receptor signaling and regulation of myeloid cell activation

2020 ◽  
pp. JVI.01654-20
Author(s):  
Ryan D. Estep ◽  
Aparna N. Govindan ◽  
Kristin Fitzpatrick ◽  
Tiffany C. Blair ◽  
S.A. Rahim Rezaee ◽  
...  
Keyword(s):  
Immune Responses ◽  
Rhesus Macaque ◽  
Cell Activation ◽  
Myeloid Cell ◽  
Functional Protein ◽  
Dna Viruses ◽  
Cd200 Receptor ◽  
First Time

The CD200-CD200R pathway is involved in inhibition of immune responses, and the importance of this pathway to infectious disease is highlighted by the fact that viral CD200 (vCD200) molecules have been found to be encoded by several DNA viruses, including the human gammaherpesvirus Kaposi’s sarcoma-associated herpesvirus (KSHV), and the closely related rhesus macaque rhadinovirus (RRV). KSHV vCD200 is the most extensively studied vCD200 molecule, however, the only herpesvirus vCD200 molecule to be examined in vivo is that encoded by RRV. Our prior studies have demonstrated that RRV vCD200 is a functional CD200 homologue that is capable of affecting immune responses in vivo, and further, that RRV can express a secreted form of vCD200 (vCD200-Sec) during infection. Despite this information, RRV vCD200 has not been examined specifically for effects on RM CD200R signaling, and the functionality of vCD200-Sec has not been examined in any context. Thus, we developed an in vitro model system in which B cells expressing vCD200 were utilized to assess the effects of this molecule on the regulation of myeloid cells expressing RM CD200R, mimicking interactions that are predicted to occur in vivo. Our findings suggest that RRV vCD200 can bind and induce functional signals through RM CD200R, while vCD200-Sec represents a non-functional protein incapable of affecting CD200R signaling. We also provide the first demonstration of the function of RM CD200, which appears to possess more robust signaling capabilities than RRV vCD200, and also show that KSHV vCD200 does not efficiently induce signaling via RM CD200R.IMPORTANCE Viral CD200 homologues are encoded by KSHV and the closely related RRV. Though RRV vCD200 has been examined, questions still exist in regard to the ability of this molecule to induce signaling via rhesus macaque CD200R, as well as the potential function of a secreted form of vCD200. Further, all previous in vitro studies of RRV vCD200 have utilized an Fc fusion protein to examine functionality, which does not replicate the structural properties of the membrane-associated form of vCD200 that is naturally produced during RRV infection. In this study, we demonstrate for the first time that membrane-expressed RRV vCD200 is capable of inducing signal transduction via RM CD200R, while the secreted form of vCD200 appears to be non-functional. Further, we also demonstrate that RM CD200 induces signaling via RM CD200R, and is more robust than RRV vCD200, while KSHV vCD200 does not appear to induce efficient signaling via RM CD200R.

scholarly journals Cholesterol Metabolic Reprogramming in Cancer and Its Pharmacological Modulation as Therapeutic Strategy

2021 ◽  
Vol 11 ◽  
Author(s):  
Isabella Giacomini ◽  
Federico Gianfanti ◽  
Maria Andrea Desbats ◽  
Genny Orso ◽  
Massimiliano Berretta ◽  
...  
Keyword(s):  
De Novo ◽  
Mevalonate Pathway ◽  
Cholesterol Metabolism ◽  
Tumor Development ◽  
Cholesterol Homeostasis ◽  
Metabolic Reprogramming ◽  
Protein Prenylation ◽  
Pharmacological Targets

Cholesterol is a ubiquitous sterol with many biological functions, which are crucial for proper cellular signaling and physiology. Indeed, cholesterol is essential in maintaining membrane physical properties, while its metabolism is involved in bile acid production and steroid hormone biosynthesis. Additionally, isoprenoids metabolites of the mevalonate pathway support protein-prenylation and dolichol, ubiquinone and the heme a biosynthesis. Cancer cells rely on cholesterol to satisfy their increased nutrient demands and to support their uncontrolled growth, thus promoting tumor development and progression. Indeed, transformed cells reprogram cholesterol metabolism either by increasing its uptake and de novo biosynthesis, or deregulating the efflux. Alternatively, tumor can efficiently accumulate cholesterol into lipid droplets and deeply modify the activity of key cholesterol homeostasis regulators. In light of these considerations, altered pathways of cholesterol metabolism might represent intriguing pharmacological targets for the development of exploitable strategies in the context of cancer therapy. Thus, this work aims to discuss the emerging evidence of in vitro and in vivo studies, as well as clinical trials, on the role of cholesterol pathways in the treatment of cancer, starting from already available cholesterol-lowering drugs (statins or fibrates), and moving towards novel potential pharmacological inhibitors or selective target modulators.

scholarly journals VISTA Is a Novel Regulator of Macrophage Biology

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2320-2320
Author(s):  
Parth Shah ◽  
Mohamed Eltanbouly ◽  
Nicole Smits ◽  
Aurelien Sarde ◽  
Randolph Noelle ◽  
...  
Keyword(s):  
T Cell Activation ◽  
Cell Biology ◽  
Time Course ◽  
Cell Activation ◽  
Myeloid Cells ◽  
Myeloid Cell ◽  
Mouse Bone Marrow ◽  
Rna Seq

Background:V-domain Ig suppressor of T cell activation (VISTA) is an immune checkpoint receptor with an established role as an inhibitory receptor on T cells. However, its role in myeloid cell biology remains unclear. Owing to the much higher expression of VISTA on monocytes and macrophages, we investigated its role in regulating myeloid biology. Methods: Mouse bone marrow-derived macrophages (BMDMs) were differentiated and treated with agonistic anti-VISTA mAb under steady-state and conditions of M1 inflammatory polarization (LPS + IFN-𝛾). Human CD14+ monocytes were isolated from peripheral blood and treated with anti-VISTA in vitro. Phosphoarrays were used to assess signaling downstream of VISTA engagement and Luminex analysis was used to evaluate cytokine production. Time-course total RNA-seq was performed on BMDMs (at 1, 2, 4, 8 and 16 hours of anti-VISTA treatment). To evaluate the effect of anti-VISTA in vivo, single-cell RNA-seq (scRNA-seq) was performed on FACS sorted CD11b+ myeloid populations 12 hours after mice were treated with intravenous anti-VISTA. Results: Anti-VISTA treatment of BMDMs and human monocytes in vitro induced rapid phosphorylation events including robust phosphorylation of Raf-1 kinase at the suppressive serine residue 43.Next, we generated a comprehensive timestamp of VISTA activation in BMDMs in vitro by time-course deep RNA-seq analysis of agonistic anti-VISTA treated cells under rigorous M1 inflammatory polarization. This revealed a unique activation state marked by the upregulation of inhibitory cytokines IL-10 and IL1RA as well as ablation of IL-12 family cytokines, suggestive of an M2-like signature. The presence of an M2-like immunoregulatory signature defined by upregulation of the IL-10 was also seen in macrophages identified post clustering of in vivo scRNA-seq data on myeloid cells. Conclusion: Using novel agonistic anti-VISTA antibodies, we reveal that VISTA triggering on myeloid cells can induce an alternative anti-inflammatory cell-state, even under conditions of strong inflammatory polarization. This introduces VISTA as an intrinsic checkpoint of macrophage tolerance. Disclosures Noelle: Immunext: Employment, Equity Ownership, Patents & Royalties, Research Funding.

scholarly journals Rapamycin Modulates the Proinflammatory Memory-Like Response of Microglia Induced by BAFF

2021 ◽  
Vol 12 ◽  
Author(s):  
Jianing Wang ◽  
Chunshu Yang ◽  
Xiaoyu Hou ◽  
Jingyi Xu ◽  
Yang Yun ◽  
...  
Keyword(s):  
Microglial Activation ◽  
Adaptive Immune System ◽  
Current Data ◽  
Metabolic Reprogramming ◽  
Microglial Cells ◽  
Trained Immunity ◽  
Cytokines And Chemokines ◽  
Bv2 Cells

BackgroundRecently trained immunity of microglia provided an opportunity to study the chronic effect of microglial activation and its metabolic rewiring in neuroimmunological diseases. Since elevated levels of B cell-activating factor (BAFF) have been proved to be associated with some chronic neuroimmunological disorders. Here, we used the trained innate immunity model to analyze the effect of BAFF, a vital regulator of the adaptive immune system, on long-term microglial activation and metabolic reprogramming in vitro and in vivo.Methods and resultsIn vitro, BV2 cells and mouse primary microglial cells were incubated with BAFF for 24 h (BAFF priming). After 5 days of resting, microglia were restimulated with LPS (LPS restimulation) or BAFF (BAFF restimulation). BAFF priming induced a pro-inflammatory trained immunity-phenotype of both BV2 cells and primary microglial cells, which was indicated by morphological change, secretion of pro-inflammatory cytokine and chemokine upon LPS restimulation or BAFF restimulation. The production of lactate and NAD+/NADH ratio were elevated 5 days after BAFF priming. The activation of the Akt/mTOR/HIF-1α pathway was induced by BAFF priming and lasted for 5 days. Pretreating the BV2 cells or mouse primary microglial cells with rapamycin blocked mTOR/HIF-1α activation and cellular metabolic reprogramming induced by BAFF training. Consistently, rapamycin efficiently suppressed the trained immunity-like responses of microglia triggered by BAFF. In vivo, adult male mice were treated withBAFF by intracerebroventricular injection for priming and 7 days later with BAFF for restimulation. BAFF training activated microglia in the cortex and hippocampus. The production of proinflammatory cytokines and chemokines was elevated after BAFF training.ConclusionOur current data, for the first time, demonstrate that BAFF priming induces a proinflammatory memory-like response of microglia not only to LPS but also to BAFF itself. Rapamycin inhibits microglial priming triggered by BAFF through targeting the mTOR/HIF-1α signaling pathway. Our data reveal a novel role of BAFF in trained immunity and that rapamycin may be a potential therapeutic target of neuroimmunological diseases.

scholarly journals Trained immunity induced by in vivo peptide-based STAT6 inhibition prevents ragweed allergy in mice

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Husheem Michael ◽  
Yuanyi Li ◽  
Yufa Wang ◽  
Christine T. McCusker
Keyword(s):  
Immune Response ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Regulatory Cells ◽  
Specific Ige ◽  
Immune Memory ◽  
Gene Expressions ◽  
Inhibitory Peptide ◽  
Trained Immunity

Abstract Background Trained immunity is the ability of the innate immune system to form immune memory responses to provide support the formation of appropriate adaptive responses. Allergic airways disease (AAD) is a maladapted immune response to allergens, initiated and maintained by the type 2 (T2) inflammatory pathway. It is predicated by the elaboration of cytokines IL-4 and IL-13 and follows activation of the STAT6 transcription factor. Objective To investigate the role of trained immunity in mucosal immune responses following neonatal vaccination with the STAT6 inhibitory peptide (STAT6-IP), in preventing the development of ragweed-induced AAD. Methods We demonstrate that transfer of CD4+ T cells or dendritic cells (DC) from STAT6-IP vaccinated wild-type BALB/c mice to naïve mice, that were subsequently chronically exposed to sensitizing doses of ragweed allergen, is sufficient to prevent development of T2 responses in recipients. Results Our results demonstrate significant reductions in; airways hyperresponsiveness (AHR); ragweed-specific IgE; pulmonary inflammation; T2 cytokines; and inflammatory gene expressions in recipient mice. Expression of IDO, TGFβ and T regulatory cells were all significantly increased. Anti-TGFβ treatment during the ragweed sensitization phase re-constituted the pro-inflammatory T2 immune response. We show that tolerance can be attained via DC trained in the STAT6-IP-mediated tolerant milieu. This effect is not restricted to a particular allergen and does not require antigen-mediated T cell activation prior to transfer. Conclusion Adoptive transfer experiments suggest that STAT6-IP treatment trains dendritic and cells to mediate tolerant immunity to chronic ragweed exposure in the airways. This indicates that early transient STAT6-inhibition constitutes an effective immunomodulatory airways allergy preventative strategy.

scholarly journals 585 LIGHT (TNFSF14) co-stimulation enhances myeloid cell activation and anti-tumor immunity in the setting of PD-1 and TIGIT checkpoint blockade

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A615-A615
Author(s):  
George Fromm ◽  
Kyung Jin Yoo ◽  
Kellsey Johannes ◽  
Casey Shuptrine ◽  
Zach Opheim ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Activation ◽  
Acquired Resistance ◽  
Myeloid Cells ◽  
Myeloid Cell ◽  
Preclinical Model ◽  
And Function ◽  
Anti Tumor Activity

BackgroundCo-inhibition of TIGIT and PD-1/L1 improves response rates compared to monotherapy PD-1/L1 blockade in checkpoint naïve NSCLC with PD-L1 expression >50%. TIGIT mAbs with an effector competent Fc can induce myeloid cell activation, and some have also demonstrated effector T cell depletion, which carries a clinical liability of unknown significance. TIGIT antibody blockade translates to anti-tumor activity by enabling PVR signaling through CD226 (DNAM-1), which can be directly inhibited by PD-1. Further, DNAM-1 is downregulated on TIL in advanced and CPI resistant cancers. Therefore, broadening clinical responses from TIGIT blockade into PD-L1low or CPI resistant tumors, may be enhanced by immune co-stimulation that independently operates from PD-1/L1 inhibition.MethodsMouse and human TIGIT-Fc-LIGHT molecules were generated and assessed using Octet, MSD, and cell binding assays, and function was evaluated using in vitro/in vivo activation and anti-tumor efficacy experiments; including a preclinical model engineered to mimic human CPI acquired resistance.ResultsTIGIT-Fc-LIGHT was nominated using in vitro and genomic screening assays designed to identify TNF costimulatory receptors widely expressed on TIL, T stem cell memory (Tscm), and NK cells; relative to DNAM-1 expression. HVEM was prioritized, and its ligand TNFSF14 (LIGHT) also directly activates myeloid cells through binding to a second receptor, LTβR. TIGIT-Fc-LIGHT simultaneously engaged TIGIT and LIGHT receptors at low nanomolar affinities (~3.5–6.5 nM), without the requirement for an effector competent Fc. HVEM signaling overlaps with DNAM-1, and TIGIT-Fc-LIGHT activated canonical and non-canonical NFκB pathways, leading to increased tumor infiltration of antigen-specific CD8+ T and NK cells. Importantly, anti-tumor efficacy induced by monotherapy TIGIT-Fc-LIGHT was maintained in aggressive anti-PD-1 acquired resistant tumors, a model where combined PD-1 and TIGIT antibody blockade was inactive. Because HVEM lacks cytoplasmic domain homology to DNAM-1, HVEM signaling is unlikely to be regulated by PD-1. Indeed, while anti-tumor activity of TIGIT-Fc-LIGHT was enhanced by PD-1/L1 blockade, it was not dependent upon combination. TIGIT-Fc-LIGHT also directly activated myeloid cells and increased the expression of CXCL10 and CXCL11, and stimulated proinflammatory cytokines, including CCL2, CCL4, and CXCL13.ConclusionsTIGIT-Fc-LIGHT was designed to overcome the limitations of TIGIT blocking antibodies through: 1) preserved costimulation in advanced tumors, 2) direct myeloid cell activation, 3) blockade of all known TIGIT ligands, and with 4) no risk of depleting effector lymphocytes since TIGIT-Fc-LIGHT activity does not require Fc function. Pre-clinical data indicate that these goals were achieved, and further development is warranted.

scholarly journals 782 PD-L1-targeted ISAC combines myeloid cell activation, immune-checkpoint inhibition and ADCP to improve anti-tumor efficacy over anti-PD-L1 antibodies in preclinical models

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A817-A817
Author(s):  
Justin Kenkel ◽  
Rishali Gadkari ◽  
Karla Henning ◽  
Romas Kudirka ◽  
William Mallet ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Cells ◽  
Immune Checkpoint ◽  
Cell Activation ◽  
Myeloid Cell ◽  
Checkpoint Inhibition ◽  
Immune Checkpoint Inhibition ◽  
Tumor Models

BackgroundPD-L1 is an immune checkpoint that regulates anti-tumor T cell responses and is expressed on tumor cells as well as tumor-infiltrating immune cells across many tumor types. Immune-stimulating antibody conjugates (ISACs) consist of tumor-targeting antibodies conjugated to immune stimulants and are designed to activate the innate and adaptive immune systems against tumor cells following systemic administration. Here we show that PD-L1-targeted TLR7/8 ISACs elicit robust myeloid cell activation which leads to improved anti-tumor responses compared to anti-PD-L1 treatment in pre-clinical tumor models.MethodsA panel of proprietary anti-PD-L1 antibodies was identified through a phage display screen and subsequently tested for PD-L1 binding affinity and specificity, PD-L1/PD-1 blocking, antibody-dependent cellular phagocytosis (ADCP) by myeloid cells, and anti-tumor efficacy. Lead antibodies were conjugated to proprietary TLR7/8 agonists, and the resulting PD-L1 ISACs were evaluated for in vitro myeloid cell activation and in vivo efficacy against syngeneic and xenograft tumors.ResultsAnti-PD-L1 antibodies induced robust ADCP by myeloid effector cells and medium to strong PD-L1/PD-1 blockade in vitro. Selected antibodies inhibited the growth of syngeneic MC38-hPD-L1 tumors in vivo, confirming efficient immune-checkpoint blockade. The conjugated PD-L1 ISACs induced robust, target-dependent activation of myeloid cells when co-cultured with PD-L1-expressing tumor cells, as measured by increased secretion of such cytokines as IL-12p70, IFN-alpha, and TNF-alpha. Importantly, myeloid activation was observed following co-culture with tumor cells having various levels of endogenous PD-L1 expression that was within the range of PD-L1 expression observed in human tumors. Systemically administered surrogate PD-L1 ISACs were well tolerated in mice and showed improved anti-tumor efficacy over anti-PD-L1 antibodies, with significant tumor growth delay or complete responses frequently observed in syngeneic (e.g. MB49, MC38-hPD-L1) as well as xenograft (e.g. HCC1954-hPD-L1) tumor models.ConclusionsThese data demonstrate the potential of a PD-L1-targeted ISAC as a multifunctional therapeutic that may improve efficacy of PD-L1/PD-1 inhibition by combining three mechanisms of action into a single molecule: TLR-mediated myeloid cell activation, T cell activation through immune-checkpoint inhibition as well as ADCP.Ethics ApprovalAll animal studies were performed in accordance with Institutional Animal Care and Use Committee (IACUC)-approved protocols.

Sign in / Sign up

Export Citation Format

Share Document