Reprogramming Of Immune Cells Research Articles

Extracellular Vesicles Released by Tumor Endothelial Cells Spread Immunosuppressive and Transforming Signals Through Various Recipient Cells.

Head and neck squamous cell carcinoma (HNSCC) has a high recurrence and metastatic rate with an unknown mechanism of cancer spread. Tumor inflammation is the most critical processes of cancer onset, growth, and metastasis. We hypothesize that the release of extracellular vesicles (EVs) by tumor endothelial cells (TECs) induce reprogramming of immune cells as well as stromal cells to create an immunosuppressive microenvironment that favor tumor spread. We call this mechanism as non-metastatic contagious carcinogenesis. Extracellular vesicles were collected from primary HNSCC-derived endothelial cells (TEC-EV) and were used for stimulation of peripheral blood mononuclear cells (PBMCs) and primary adipose mesenchymal stem cells (ASCs). Regulation of ASC gene expression was investigated by RNA sequencing and protein array. PBMC, stimulated with TEC-EV, were analyzed by enzyme-linked immunosorbent assay and fluorescence-activated cell sorting. We validated in vitro the effects of TEC-EV on ASCs or PBMC by measuring invasion, adhesion, and proliferation. We found and confirmed that TEC-EV were able to change ASC inflammatory gene expression signature within 24–48 h. TEC-EV were also able to enhance the secretion of TGF-β1 and IL-10 by PBMC and to increase T regulatory cell (Treg) expansion. TEC-EV carry specific proteins and RNAs that are responsible for Treg differentiation and immune suppression. ASCs and PBMC, treated with TEC-EV, enhanced proliferation, adhesion of tumor cells, and their invasion. These data indicate that TEC-EV exhibit a mechanism of non-metastatic contagious carcinogenesis that regulates tumor microenvironment and reprograms immune cells to sustain tumor growth and progression.

Metabolomic Profiling Reveals Distinct and Mutual Effects of Diet and Inflammation in Shaping Systemic Metabolism in Ldlr-/- Mice.

Changes in modern dietary habits such as consumption of Western-type diets affect physiology on several levels, including metabolism and inflammation. It is currently unclear whether changes in systemic metabolism due to dietary interventions are long-lasting and affect acute inflammatory processes. Here, we investigated how high-fat diet (HFD) feeding altered systemic metabolism and the metabolomic response to inflammatory stimuli. We conducted metabolomic profiling of sera collected from Ldlr−/− mice on either regular chow diet (CD) or HFD, and after an additional low-dose lipopolysaccharide (LPS) challenge. HFD feeding, as well as LPS treatment, elicited pronounced metabolic changes. HFD qualitatively altered the systemic metabolic response to LPS; particularly, serum concentrations of fatty acids and their metabolites varied between LPS-challenged mice on HFD or CD, respectively. To investigate whether systemic metabolic changes were sustained long-term, mice fed HFD were shifted back to CD after four weeks (HFD > CD). When shifted back to CD, serum metabolites returned to baseline levels, and so did the response to LPS. Our results imply that systemic metabolism rapidly adapts to dietary changes. The profound systemic metabolic rewiring observed in response to diet might affect immune cell reprogramming and inflammatory responses.

Metabolic reprogramming as a key regulator in the pathogenesis of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease with synovitis as pathological changes. The immune microenvironment of RA promotes metabolic reprogramming of immune cells and stromal cells, which leads to dysfunction and imbalance of immune homeostasis. Cell metabolism undergoes the switch from a static regulatory state to a highly metabolic active state, which changes the redox-sensitive signaling pathway and also leads to the accumulation of metabolic intermediates, which in turn can act as signaling molecules and further aggravate the inflammatory response. The reprogramming of immunometabolism affects the function of immune cells and is crucial to the pathogenesis of RA. In addition, mitochondrial dysfunction plays a key role in glycolytic reprogramming in RA. These metabolic changes may be potential therapeutic targets for RA. Therefore, we reviewed the metabolic reprogramming of RA immune cells and fibroblast-like synovium cells (FLS) and its relationship with mitochondrial dysfunction. A computer-based online search was performed using the PubMed database and Web of Science database for published articles concerning immunometabolic reprogramming, mitochondrial dysfunction, and rheumatoid arthritis. This article reviews the metabolic reprogramming of immune cells and fibroblast-like synoviocytes in RA and their relationship to mitochondrial disfunction, as well as the key pro-inflammatory pathways associated with metabolic reprogramming and chemotherapy as a potential future therapeutic strategy for RA.

Cardiometabolic risk factors are associated with immune cell mitochondrial respiration in humans.

Modifiable cardiometabolic risk factors induce the release of proinflammatory cytokines and reactive oxygen species from circulating peripheral blood mononuclear cells (PBMCs), resulting in increased cardiovascular disease risk and compromised immune health. These changes may be driven by metabolic reprogramming of PBMCs, resulting in reduced mitochondrial respiration; however, this has not been fully tested. We aimed to determine the independent associations between cardiometabolic risk factors including BMI, blood pressure, fasting glucose, and plasma lipids with mitochondrial respiration in PBMCs isolated from generally healthy individuals (n = 21) across the adult lifespan (12 men/9 women; age, 56 ± 21 yr; age range, 22-78 yr; body mass index, 27.9 ± 5.7 kg/m2; blood pressure, 123 ± 16/72 ± 10 mmHg; glucose, 90 ± 14 mg/dL; low-density lipoprotein cholesterol (LDL-C), 111 ± 22 mg/dL; and high-density lipoprotein cholesterol (HDL-C), 62 ± 16 mg/dL). PBMCs were isolated from whole blood by density-dependent centrifugation and used to assess mitochondrial function by respirometry. Primary outcomes included basal and maximal oxygen consumption rate (OCR), which were subsequently used to determine spare respiratory capacity and OCR metabolic potential. After we corrected for systolic blood pressure (SBP), diastolic blood pressure (DBP), and blood glucose, LDL-C was negatively associated with maximal respiration (r = -0.56, P = 0.016), spare respiratory capacity (r = -0.58, P = 0.012), and OCR metabolic potential (r = -0.71, P = 0.0011). In addition, SBP was negatively associated with OCR metabolic potential (r = -0.62, P = 0.0056) after we corrected for DBP, blood glucose, and LDL-C. These data suggest a link between blood cholesterol, SBP, and mitochondrial health that may provide insight into how cardiometabolic risk factors contribute to impaired immune cell function.NEW & NOTEWORTHY Independent of other cardiometabolic risk factors, low-density lipoprotein cholesterol, and systolic blood pressure were found to be negatively associated with several parameters of mitochondrial respiration in peripheral blood mononuclear cells of healthy adults. These data suggest that low-density lipoprotein cholesterol and systolic blood pressure may induce metabolic reprogramming of immune cells, contributing to increased cardiovascular disease risk and impaired immune health.

Targeting immunometabolism as an anti-inflammatory strategy

The growing field of immunometabolism has taught us how metabolic cellular reactions and processes not only provide a means to generate ATP and biosynthetic precursors, but are also a way of controlling immunity and inflammation. Metabolic reprogramming of immune cells is essential for both inflammatory as well as anti-inflammatory responses. Four anti-inflammatory therapies, DMF, Metformin, Methotrexate and Rapamycin all work by affecting metabolism and/or regulating or mimicking endogenous metabolites with anti-inflammatory effects. Evidence is emerging for the targeting of specific metabolic events as a strategy to limit inflammation in different contexts. Here we discuss these recent developments and speculate on the prospect of targeting immunometabolism in the effort to develop novel anti-inflammatory therapeutics. As accumulating evidence for roles of an intricate and elaborate network of metabolic processes, including lipid, amino acid and nucleotide metabolism provides key focal points for developing new therapies, we here turn our attention to glycolysis and the TCA cycle to provide examples of how metabolic intermediates and enzymes can provide potential novel therapeutic targets.

Advantages and Limitations of the Neonatal Immune System.

During early post-natal life, neonates must adjust to the transition from the sheltered intra-uterine environment to the microbe-laden external world, wherein they encounter a constellation of antigens and the colonization by the microbiome. At this vulnerable stage, neonatal immune responses are considered immature and present significant differences to those of adults. Pertinent to innate immunity, functional and quantitative deficiencies in antigen-presenting cells and phagocytes are often documented. Exposure to environmental antigens and microbial colonization is associated with epigenetic immune cell reprogramming and activation of effector and regulatory mechanisms that ensure age-depended immune system maturation and prevention of tissue damage. Moreover, neonatal innate immune memory has emerged as a critical mechanism providing protection against infectious agents. Still, in neonates, inexperience to antigenic exposure, along with enhancement of tissue-protective immunosuppressive mechanisms are often associated with severe immunopathological conditions, including sepsis and neurodevelopmental disorders. Despite significant advances in the field, adequate vaccination in newborns is still in its infancy due to elemental restrictions associated also with defective immune responses. In this review, we provide an overview of neonatal innate immune cells, highlighting phenotypic and functional disparities with their adult counterparts. We also discuss the effects of epigenetic modifications and microbial colonization on the regulation of neonatal immunity. A recent update on mechanisms underlying dysregulated neonatal innate immunity and linked infectious and neurodevelopmental diseases is provided. Understanding of the mechanisms that augment innate immune responsiveness in neonates may facilitate the development of improved vaccination protocols that can protect against pathogens and organ damage.

Immune-mediated anti-tumor effects of metformin; targeting metabolic reprogramming of T cells as a new possible mechanism for anti-cancer effects of metformin

Immunotherapy-based cancer treatment has revolutionized the era of cancer patients recuperation and it has brought a strong hope to treatment of some types of cancers. Metformin, a widely used antidiabetic drug, which has intensely been studied for its anticancer effects, is believed to have positive influences on immune responses against tumor cells. Metformin can affect metabolic pathways within cells mainly through activation of AMPK. Metabolic restriction of tumor microenvironment on effector immune cells is one of the important strategies favoring tumor cells to escape from immunogenic cell death. The metabolism of T cells has an axial role in shaping and supporting immune responses and may have an important role in anticancer immunity, suggesting that the functionality and durability of tumor-specific T cells need sufficient energy and nutrients. Energy biogenesis of tumor-specific cytotoxic T cells has become an interesting field of study and it is suggested that activation and maintenance of effector T cell responses in tumor microenvironment may occur by metabolic reprogramming of T cells. AMPK has been noticed as the main intracellular energy sensor and mitochondrial biogenesis key regulator which can control and regulate metabolic reprogramming in immune cells and increase antitumor immunity. Metabolic reprogramming of T cells to overcome metabolic restriction in tumor microenvironment, maiming effector T cell responses against tumor cells, has been noticed by several studies. Here we represent metformin, an AMPK activator, as a new candidate drug for metabolic reprogramming of tumor-specific T cells to increase the efficacy and accountability of cancer immunotherapy.

The balance between breast cancer and the immune system: Challenges for prognosis and clinical benefit from immunotherapies.

Cancer evolution is a complex process influenced by genetic factors and extracellular stimuli that trigger signaling pathways to coordinate the continuous and dynamic interaction between tumor cells and the elements of the immune system. For over 20 years now, the immune mechanisms controlling cancer progression have been the focus of intensive research. It is well established that the immune system conveys protective antitumor immunity by destroying immunogenic tumor variants, but also facilitates tumor progression by shaping tumor immunogenicity in a process called "immunoediting". It is also clear that immune-guided tumor editing is associated with tumor evasion from immune surveillance and therefore reinforcing the endogenous antitumor immunity is a desired goal in the context of cancer therapies. The tumor microenvironment (TME) is a complex network which consists of various cell types and factors having important roles regarding tumor development and progression. Tumor infiltrating lymphocytes (TILs) and other tumor infiltrating immune cells (TIICs) are key to our understanding of tumor immune surveillance based on tumor immunogenicity, whereby the densities and location of TILs and TIICs in the tumor regions, as well as their functional programs (comprising the "immunoscore") have a prominent role for prognosis and prediction for several cancers. The presence of tertiary lymphoid structures (TLS) in the TME or in peritumoral areas has an influence on the locally produced antitumor immune response, and therefore also has a significant prognostic impact. The cross-talk between elements of the immune system with tumor cells in the TME is greatly influenced by hypoxia, the gut and/or the local microbiota, and several metabolic elements, which, in a dynamic interplay, have a crucial role for tumor cell heterogeneity and reprogramming of immune cells along their activation and differentiation pathways. Taking into consideration the recent clinical success with the application immunotherapies for the treatment of several cancer types, increasing endeavors have been made to gain better insights into the mechanisms underlying phenotypic and metabolic profiles in the context of tumor progression and immunotherapy. In this review we will address (i) the role of TILs, TIICs and TLS in breast cancer (BCa); (ii) the different metabolic-based pathways used by immune and breast cancer cells; and (iii) implications for immunotherapy-based strategies in BCa.

Metabolic reprogramming of Salmonella infected macrophages and its modulation by iron availability and the mTOR pathway.

Iron is an essential nutrient for immune cells and microbes, therefore the control of its homeostasis plays a decisive role for infections. Moreover, iron affects metabolic pathways by modulating the translational expression of the key tricarboxylic acid cycle (TCA) enzyme mitochondrial aconitase and the energy formation by mitochondria. Recent data provide evidence for metabolic re-programming of immune cells including macrophages during infection which is centrally controlled by mTOR. We herein studied the effects of iron perturbations on metabolic profiles in macrophages upon infection with the intracellular bacterium Salmonella enterica serovar Typhimurium and analysed for a link to the mTOR pathway. Infection of the murine macrophage cell line RAW264.7 with Salmonella resulted in the induction of mTOR activity, anaerobic glycolysis and inhibition of the TCA activity as reflected by reduced pyruvate and increased lactate levels. In contrast, iron supplementation to macrophages not only affected the mRNA expression of TCA and glycolytic enzymes but also resulted in metabolic reprogramming with increased pyruvate accumulation and reduced lactate levels apart from modulating the concentrations of several other metabolites. While mTOR slightly affected cellular iron homeostasis in infected macrophages, mTOR inhibition by rapamycin resulted in a significant growth promotion of bacteria. Importantly, iron further increased bacterial numbers in rapamycin treated macrophages, however, the metabolic profiles induced by iron in the presence or absence of mTOR activity differed in several aspects. Our data indicate, that iron not only serves as a bacterial nutrient but also acts as a metabolic modulator of the TCA cycle, partly reversing the Warburg effect and resulting in a pathogen friendly nutritional environment.

Leptin induces TNF\u03b1-dependent inflammation in acquired generalized lipodystrophy and combined Crohn\u2019s disease

Leptin has been shown to modulate intestinal inflammation in mice. However, clinical evidence regarding its immune-stimulatory potential in human Crohn’s disease remains sparse. We here describe a patient with the unique combination of acquired generalized lipodystrophy and Crohn’s disease (AGLCD) featuring a lack of adipose tissue, leptin deficiency and intestinal inflammation. Using mass and flow cytometry, immunohistochemistry and functional metabolic analyses, the AGLCD patient was compared to healthy individuals and Crohn’s disease patients regarding immune cell composition, function and metabolism and the effects of recombinant N-methionylleptin (rLeptin) were evaluated. We provide evidence that rLeptin exerts diverse pro-inflammatory effects on immune cell differentiation and function, including the metabolic reprogramming of immune cells and the induction of TNFα, ultimately aggravating Crohn’s disease in the AGLCD patient, which can be reversed by anti-TNFα therapy. Our results indicate that leptin is required for human immune homeostasis and contributes to autoimmunity in a TNFα-dependent manner.

Nanoparticles for Immune Cell Reprogramming and Reengineering of Tumor Microenvironment.

Nanoparticles in cancer therapy have garnered significant attention in the past few decades. Cancer immunotherapy, which is aptly called "the new-generation cancer therapy," is slowly making remarkable strides in the improvement of patient outcome and longevity. Taken together, nanoparticles in immune therapy have the potential to offer advantages of both nanoparticles and immune therapy on a single platform.

Osteoarthritis-associated basic calcium phosphate crystals alter immune cell metabolism and promote M1 macrophage polarization

A number of studies have demonstrated that molecules called 'alarmins' or danger-associated molecular patterns (DAMPs), contribute to inflammatory processes in the OA joint. Metabolic reprogramming of immune cells, including macrophages, is emerging as a prominent player in determining immune cell phenotype and function. The aim of this study was to investigate if basic calcium phosphate (BCP) crystals which are OA-associated DAMPs, impact on macrophage phenotype and metabolism. Human monocyte derived macrophages were treated with BCP crystals and expression of M1 (CXCL9, CXCL10) and M2 (MRC1, CCL13)-associated markers was assessed by real-time PCR while surface maturation marker (CD40, CD80 & CD86) expression was assessed by flow cytometry. BCP induced metabolic changes were assessed by Seahorse analysis and glycolytic marker expression (hexokinase 2(HK2), Glut1 and HIF1α) was examined using real-time PCR and immunoblotting. Treatment with BCP crystals upregulated mRNA levels of CXCL9 and CXCL10 while concomitantly downregulating expression of CCL13 and MRC1. Furthermore, BCP-treated macrophages enhanced surface expression of the maturation makers, CD40, CD80 and CD86. BCP-treated cells also exhibited a shift towards glycolysis as evidenced by an increased ECAR/OCR ratio and enhanced expression of the glycolytic markers, HK2, Glut1 and HIF1α. Finally, BCP-induced macrophage activation and alarmin expression was reduced in the presence of the glycolytic inhibitor, 2-DG. This study not only provides further insight into how OA-associated DAMPs impact on immune cell function, but also highlights metabolic reprogramming as a potential therapeutic target for calcium crystal-related arthropathies.

Lipid signalling drives proteolytic rewiring of mitochondria by YME1L.

Reprogramming of mitochondria provides cells with the metabolic flexibility required to adapt to various developmental transitions such as stem cell activation or immune cell reprogramming, and to respond to environmental challenges such as those encountered under hypoxic conditions or during tumorigenesis1-3. Here we show that the i-AAA protease YME1L rewires the proteome of pre-existing mitochondria in response to hypoxia or nutrient starvation. Inhibition of mTORC1 induces a lipid signalling cascade via the phosphatidic acid phosphatase LIPIN1, which decreases phosphatidylethanolamine levels in mitochondrial membranes and promotes proteolysis. YME1L degrades mitochondrial protein translocases, lipid transfer proteins and metabolic enzymes to acutely limit mitochondrial biogenesis and support cell growth. YME1L-mediated mitochondrial reshaping supports the growth of pancreatic ductal adenocarcinoma (PDAC) cells as spheroids or xenografts. Similar changes to the mitochondrial proteome occur in the tumour tissues of patients with PDAC, suggesting that YME1L is relevant to the pathophysiology of these tumours. Our results identify the mTORC1-LIPIN1-YME1L axis as a post-translational regulator of mitochondrial proteostasis at the interface between metabolism and mitochondrial dynamics.

P2.04-42 PD-L1-Mediated Enhancement of Hexokinase 2 Expression Is Inversely Related to T-Cell Effector Gene Expression in Non-Small-Cell Lung Cancer

The PD-1/PD-L1 pathway contributes to the metabolic reprogramming of immune cells and tumor cells. However, the mechanism by which PD-L1 regulates glycolysis in human cancer and the relationship between PD-L1 expression, glycose metabolism and anti-tumor immune response remain unclear. We addressed these issues in human non-small-cell lung cancer (NSCLC). Changes in glycolysis-related molecules and glycolytic activity were evaluated in PD-L1low and PD-L1high NSCLC cells after transfection or knockdown of PD-L1, respectively. RNA seq and gene set enrichment analyses (GSEA) was also performed. The association between PD-L1 and immune response-related molecules or glycolysis were analyzed in patients with NSCLC and The Cancer Genome Atlas (TCGA). Transfecting PD-L1 in PD-L1low cells enhanced hexokinase-2 (HK2) expression, lactate production, and extracellular acidification rates, but minimally altered GLUT1 and PKM2 expression and oxygen consumption rates. Consistently, GSEA revealed that the glycolytic pathway was enhanced in PD-L1low cells after PD-L1 transfection. By contrast, knocking-down PD-L1 in PD-L1high cells decreased HK2 expression and glycolysis by suppressing PI3K/Akt and Erk pathways. Immunohistochemistry revealed that PD-L1 expression was positively correlated with HK2 expression in NSCLC tissues from patients (p<0.001). In TCGA analyses, HK2 exhibited a positive linear association with CD274 (PD-L1) expression (p<0.001) but an inverse correlation with the expression of CD4, CD8A, and T-cell effector function-related genes in the CD274high rather than CD274low group. Consistent with this, there were fewer CD8+ T-cells in PD-L1positive/HK2high tumors compared to PD-L1positive/HK2low tumors in squamous cell carcinoma. PD-L1 enhances glycolysis in NSCLC by upregulating HK2, which might dampen anti-tumor immunity. PD-L1 may contribute to NSCLC oncogenesis by inducing metabolic reprogramming and immune checkpoint pathway.

Epigenetic Reprogramming of Immune Cells in Women With PCOS Impact Genes Controlling Reproductive Function.

Polycystic ovary syndrome (PCOS) is a chronic disease affecting reproductive function and whole-body metabolism. Although the etiology is unclear, emerging evidence indicates that the epigenetics may be a contributing factor. To determine the role of global and genome-wide epigenetic modifications in specific immune cells in PCOS compared with controls and whether these could be related to clinical features of PCOS. Cross-sectional study. Women with (n = 17) or without PCOS (n = 17). Recruited from the general community. Isolated peripheral blood mononuclear cells were analyzed using multicolor flow cytometry methods to determine global DNA methylation levels in a cell-specific fashion. Transcriptomic and genome-wide DNA methylation analyses were performed on T helper cells using RNA sequencing and reduced representation bisulfite sequencing. Women with PCOS had lower global DNA methylation in monocytes (P = 0.006) and in T helper (P = 0.004), T cytotoxic (P = 0.004), and B cells (P = 0.03). Specific genome-wide DNA methylation analysis of T helper cells from women with PCOS identified 5581 differentially methylated CpG sites. Functional gene ontology enrichment analysis showed that genes located at the proximity of differentially methylated CpG sites belong to pathways related to reproductive function and immune cell function. However, these genes were not altered at the transcriptomic level. It was shown that PCOS is associated with global and gene-specific DNA methylation remodeling in a cell type-specific manner. Further investigation is warranted to determine whether epigenetic reprogramming of immune cells is important in determining the different phenotypes of PCOS.

Epigenetic reprogramming of immune cells in injury, repair, and resolution.

Immune cells are pivotal in the reaction to injury, whereupon, under ideal conditions, repair and resolution phases restore homeostasis following initial acute inflammation. Immune cell activation and reprogramming require transcriptional changes that can only be initiated if epigenetic alterations occur. Recently, accelerated deciphering of epigenetic mechanisms has extended knowledge of epigenetic regulation, including long-distance chromatin remodeling, DNA methylation, posttranslational histone modifications, and involvement of small and long noncoding RNAs. Epigenetic changes have been linked to aspects of immune cell development, activation, and differentiation. Furthermore, genome-wide epigenetic landscapes have been established for some immune cells, including tissue-resident macrophages, and blood-derived cells including T cells. The epigenetic mechanisms underlying developmental steps from hematopoietic stem cells to fully differentiated immune cells led to development of epigenetic technologies and insights into general rules of epigenetic regulation. Compared with more advanced research areas, epigenetic reprogramming of immune cells in injury remains in its infancy. While the early epigenetic mechanisms supporting activation of the immune response to injury have been studied, less is known about resolution and repair phases and cell type-specific changes. We review prominent recent findings concerning injury-mediated epigenetic reprogramming, particularly in stroke and myocardial infarction. Lastly, we illustrate how single-cell technologies will be crucial to understanding epigenetic reprogramming in the complex sequential processes following injury.

Research progress on metabolic reprogramming of innate immune cells involved in immune-regulation of sepsis

Immunosuppression plays a critical role in death of sepsis. Innate immunity is the first line defense to prevent pathogen invasion, and neutrophils, macrophages, dendritic cells and natural killer cells (NK cells) are closely involved in the process of the immune-regulation during sepsis. Recently, metabolic reprogramming in immune cells is known as a keystone for immune intervention therapy in sepsis. Here, we focus on the recent advances in metabolic regulation in neutrophils, macrophages, dendritic cells and NK cells including glycolysis, fatty acid synthesis, fatty acid oxidation and arginine metabolism involved in the immune-regulation of sepsis. This review will be helpful to summarize the mechanisms underlying sepsis-induced immunosuppression.

Central metabolic interactions of immune cells and microbes: prospects for defeating infections.

Antimicrobial drug resistance is threatening to take us to the "pre-antibiotic era", where people are dying from preventable and treatable diseases and the risk of hospital-associated infections compromises the success of surgery and cancer treatments. Development of new antibiotics is slow, and alternative approaches to control infections have emerged based on insights into metabolic pathways in host-microbe interactions. Central carbon metabolism of immune cells is pivotal in mounting an effective response to invading pathogens, not only to meet energy requirements, but to directly activate antimicrobial responses. Microbes are not passive players here-they remodel their metabolism to survive and grow in host environments. Sometimes, microbes might even benefit from the metabolic reprogramming of immune cells, and pathogens such as Candida albicans, Salmonella Typhimurium and Staphylococcus aureus can compete with activated host cells for sugars that are needed for essential metabolic pathways linked to inflammatory processes. Here, we discuss how metabolic interactions between innate immune cells and microbes determine their survival during infection, and ways in which metabolism could be manipulated as a therapeutic strategy.

OR31-4 Neonatal Vitamin D Deficiency and Insulin Resistance

Background: Vitamin D deficiency is prevalent in pregnant women and their offspring. Maternal vitamin D deficiency is associated with insulin resistance in children and can induce a proinflammatory macrophage phenotype [1, 2]. Purpose: We hypothesized that maternal vitamin D deficiency induces immune cell reprogramming that promotes adipose insulin resistance in the offspring and is detectable in the newborn period. Methods: We enrolled 32 normal pregnant women prior to delivery of AGA, term infants. Cord blood was obtained and used to determine vitamin D [25(OH)D] levels and qPCR of microRNA levels. Cord blood monocytes were co-cultured with 3T3L1 adipocytes for insulin-stimulated 2-deoxyglucose uptake studies, and the monocyte media and co-cultured adipocytes were analyzed for microRNA expression. 3T3L1 adipocytes were transfected with miR106b mimic and antagonist to confirm the effect of the 2-deoxyglucose results. Results: 83% of the newborn’s venous cord blood showed vitamin D deficiency with 25(OH)D <20 ng/mL (n=24, total n=29). Adipocytes co-cultured with cord blood monocytes showed an inverse correlation between insulin stimulated 2-deoxyglucose uptake and cord blood 25(OH)D levels (n=29, Spearman r=0.43, p=0.02). Adipocytes exposed to monocytes or to monocyte media elevated miR106b by 7 to 12-fold (n=8, p<0.01). Interestingly, cord blood plasma miR106b levels were found to inversely correlate with 25(OH)D levels (n=27, Spearman r=-0.41, p<0.04). Transfection of adipocytes with miR106b mimic reduced the 2-deoxyglucose uptake after insulin stimulation, whereas transfection with anti-miR-106b increased 2-deoxyglucose uptake after insulin stimulation, suggesting that monocyte secretion of miR106b induced adipose insulin resistance (n=8, p<0.05). Conclusions: This study provides evidence of a novel intercellular miRNA communication mechanism enabling monocytes programmed in utero by vitamin D deficiency to induce adipose insulin resistance. Identification of circulating miR106b as a mechanism of insulin resistance in offspring born with vitamin D deficiency is a potential advance toward precision medicine as it allows for optimal targeting of those at risk for diabetes later in life within a heterogeneous population. These findings serve as background for interventional studies evaluating the effect of maternal vitamin D supplementation on offspring insulin resistance later in life.

Tumor Suppressor miRNA-204-5p Regulates Growth, Metastasis, and Immune Microenvironment Remodeling in Breast Cancer.

Various miRNAs play critical roles in the development and progression of solid tumors. In this study, we describe the role of miR-204-5p in limiting growth and progression of breast cancer. In breast cancer tissues, miR-204-5p was significantly downregulated compared with normal breast tissues, and its expression levels were associated with increased survival outcome in patients with breast cancer. Overexpression of miR-204-5p inhibited viability, proliferation, and migration capacity in human and murine breast cancer cells. In addition, miR-204-5p overexpression resulted in a significant alteration in metabolic properties of cancer cells and suppression of tumor growth and metastasis in mouse breast cancer models. The association between miR-204-5p expression and clinical outcomes of patients with breast cancer showed a nonlinear pattern that was reproduced in experimental assays of cancer cell behavior and metastatic capacities. Transcriptome and proteomic analysis revealed that various cancer-related pathways including PI3K/Akt and tumor-immune interactions were significantly associated with miR-204-5p expression. PIK3CB, a major regulator of PI3K/Akt pathway, was a direct target for miR-204-5p, and the association between PIK3CB-related PI3K/Akt signaling and miR-204-5p was most evident in the basal subtype. The sensitivity of breast cancer cells to various anticancer drugs including PIK3CB inhibitors was significantly affected by miR-204-5p expression. In addition, miR-204-5p regulated expression of key cytokines in tumor cells and reprogrammed the immune microenvironment by shifting myeloid and lymphocyte populations. These data demonstrate both cell-autonomous and non-cell-autonomous impacts of tumor suppressor miR-204-5p in breast cancer progression and metastasis. SIGNIFICANCE: This study demonstrates that regulation of PI3K/Akt signaling by miR-204-5p suppresses tumor metastasis and immune cell reprogramming in breast cancer.