Extracellular HMGB1 blockade inhibits tumor growth through profoundly remodeling immune microenvironment and enhances checkpoint inhibitor-based immunotherapy

BackgroundHigh-mobility group box 1 (HMGB1) is a multifunctional redox-sensitive protein involved in various intracellular (eg, chromatin remodeling, transcription, autophagy) and extracellular (inflammation, autoimmunity) processes. Regarding its role in cancer development/progression, paradoxical results exist in the literature and it is still unclear whether HMGB1 mainly acts as an oncogene or a tumor suppressor.MethodsHMGB1 expression was first assessed in tissue specimens (n=359) of invasive breast, lung and cervical cancer and the two distinct staining patterns detected (nuclear vs cytoplasmic) were correlated to the secretion profile of malignant cells, patient outcomes and the presence of infiltrating immune cells within tumor microenvironment. Using several orthotopic, syngeneic mouse models of basal-like breast (4T1, 67NR and EpRas) or non-small cell lung (TC-1) cancer, the efficacy of several HMGB1 inhibitors alone and in combination with immune checkpoint blockade antibodies (anti-PD-1/PD-L1) was then investigated. Isolated from retrieved tumors, 14 immune cell (sub)populations as well as the activation status of antigen-presenting cells were extensively analyzed in each condition. Finally, the redox state of HMGB1 in tumor-extruded fluids and the influence of different forms (oxidized, reduced or disulfide) on both dendritic cell (DC) and plasmacytoid DC (pDC) activation were determined.ResultsAssociated with an unfavorable prognosis in human patients, we clearly demonstrated that targeting extracellular HMGB1 elicits a profound remodeling of tumor immune microenvironment for efficient cancer therapy. Indeed, without affecting the global number of (CD45+) immune cells, drastic reductions of monocytic/granulocytic myeloid-derived suppressor cells (MDSC) and regulatory T lymphocytes, a higher M1/M2 ratio of macrophages as well as an increased activation of both DC and pDC were continually observed following HMGB1 inhibition. Moreover, blocking HMGB1 improved the efficacy of anti-PD-1 cancer monoimmunotherapy. We also reported that a significant fraction of HMGB1 encountered within cancer microenvironment (interstitial fluids) is oxidized and, in opposite to its reduced isoform, oxidized HMGB1 acts as a tolerogenic signal in a receptor for advanced glycation endproducts-dependent manner.ConclusionCollectively, we present evidence that extracellular HMGB1 blockade may complement first-generation cancer immunotherapies by remobilizing antitumor immune response.

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Autophagic Markers in Chordomas: Immunohistochemical Analysis and Comparison with the Immune Microenvironment of Chordoma Tissues

Cancers ◽

10.3390/cancers13092169 ◽

2021 ◽

Vol 13 (9) ◽

pp. 2169

Author(s):

Georgia Karpathiou ◽

Maroa Dridi ◽

Lila Krebs-Drouot ◽

François Vassal ◽

Emmanuel Jouanneau ◽

...

Keyword(s):

Tumor Cell ◽

Immune Cells ◽

Immune Cell ◽

Positive Association ◽

Immunohistochemical Analysis ◽

Vascular Density ◽

Immune Microenvironment ◽

Significant Positive Association ◽

Sequestosome 1 ◽

Cell Expression

Chordomas are notably resistant to chemotherapy. One of the cytoprotective mechanisms implicated in chemoresistance is autophagy. There are indirect data that autophagy could be implicated in chordomas, but its presence has not been studied in chordoma tissues. Sixty-one (61) chordomas were immunohistochemically studied for autophagic markers and their expression was compared with the expression in notochords, clinicopathological data, as well as the tumor immune microenvironment. All chordomas strongly and diffusely expressed cytoplasmic p62 (sequestosome 1, SQSTM1/p62), whereas 16 (26.2%) tumors also showed nuclear p62 expression. LC3B (Microtubule-associated protein 1A/1B-light chain 3B) tumor cell expression was found in 44 (72.1%) tumors. Autophagy-related 16‑like 1 (ATG16L1) was also expressed by most tumors. All tumors expressed mannose-6-phosphate/insulin-like growth factor 2 receptor (M6PR/IGF2R). LC3B tumor cell expression was negatively associated with tumor size, while no other parameters, such as age, sex, localization, or survival, were associated with the immunohistochemical factors studied. LC3B immune cell expression showed a significant positive association with programmed death-ligand 1 (PD-L1)+ immune cells and with a higher vascular density. ATG16L1 expression was also positively associated with higher vascular density. Notochords (n = 5) showed different immunostaining with a very weak LC3B and M6PR expression, and no p62 expression. In contrast to normal notochords, autophagic factors such as LC3B and ATG16L1 are often present in chordomas, associated with a strong and diffuse expression of p62, suggesting a blocked autophagic flow. Furthermore, PD-L1+ immune cells also express LC3B, suggesting the need for further investigations between autophagy and the immune microenvironment.

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EXTH-32. TARGETED STAT3 INHIBITION IMPAIRS MDSC MOBILIZATION AND RECRUITMENT IN GLIOBLASTOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa215.386 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii93-ii94

Author(s):

Christina von Roemeling ◽

Chenglong Li ◽

Duane Mitchell

Keyword(s):

Immune Cell ◽

Large Fraction ◽

Single Agent ◽

Suppressor Cells ◽

Peripheral Circulation ◽

Immune Checkpoint Blockade ◽

Tumor Burden ◽

Checkpoint Blockade ◽

Specific Marker ◽

Stat3 Phosphorylation

Abstract BACKGROUND Glioblastoma tumors (GBM) are comprised upwards of 30 percent by glioma-associated myeloid cells (GAMs). A large fraction of GAMs are myeloid-derived suppressor cells (MDSC) thought to traffic in from peripheral circulation. MDSCs foster a hospitable environment for cancer cells by regulating immune suppression and driving resistance to immunotherapy. While signal transducer and activator of transcription 3 (STAT3) is considered to be a specific marker for MDSCs and is a known player in their phenotypic polarization in cancer, we sought to closely examine its specific role in MDSC trafficking and tumor recruitment. HYPOTHESIS Targeted inhibition of STAT3 blocks MDSC from the bone marrow, mitigating their accumulation within GBM tumors. METHODS Human and murine GBM samples were analyzed for immune-specific STAT3 phosphorylation (P-STAT3). Immune cell characterization and quantification in peripheral and GBM tissue from syngeneic murine models treated with a novel STAT3 inhibitor (LLL12B) was done. Therapeutic responses to LLL12B alone and in combination with immune checkpoint blockade were evaluated. RESULTS We found P-STAT3 to be predominantly expressed by tumor-associated immune cells in both human and murine GBM, particularly MDSCs. Circulating numbers of MDSCs dramatically increase in response to tumor burden. P-STAT3 is elevated in these cells, indicating that its activation occurs prior to tumor infiltration. LLL12B blockade of STAT3 significantly reduced the number of circulating and tumor-infiltrating MDSCs. As a single agent LLL12B reduced tumor volume and extended the survival of murine GBM models. When combined with anti-PD-1 checkpoint blockade, we observed durable survival in a significant fraction of treated mice. CONCLUSIONS These findings advocate a critically important role for STAT3 in regulating MDSC mobilization and trafficking to GBM tumors. It additionally reveals a new therapeutic mechanism of action for LLL12B that may be relevant for other direct inhibitors of STAT3, influencing their clinical applicability to treat GBM.

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Identification of Biomarkers Related to Immune Cell Infiltration in Hepatocellular Carcinoma Using Gene Co-Expression Network

Pathology & Oncology Research ◽

10.3389/pore.2021.601693 ◽

2021 ◽

Vol 27 ◽

Author(s):

Wanbang Zhou ◽

Yiyang Chen ◽

Ruixing Luo ◽

Zifan Li ◽

Guanwei Jiang ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Network Analysis ◽

Tumor Progression ◽

Protein Interactions ◽

Immune Cells ◽

Immune Cell ◽

Immune Microenvironment ◽

Hub Genes ◽

Expression Levels ◽

Immune Infiltration

Hepatocellular carcinoma (HCC) is a common cancer with poor prognosis. Due to the lack of effective biomarkers and its complex immune microenvironment, the effects of current HCC therapies are not ideal. In this study, we used the GSE57957 microarray data from Gene Expression Omnibus database to construct a co-expression network. The weighted gene co-expression network analysis and CIBERSORT algorithm, which quantifies cellular composition of immune cells, were used to identify modules related to immune cells. Four hub genes (EFTUD2, GAPDH, NOP56, PA2G4) were identified by co-expression network and protein-protein interactions network analysis. We examined these genes in TCGA database, and found that the four hub genes were highly expressed in tumor tissues in multiple HCC groups, and the expression levels were significantly correlated with patient survival time, pathological stage and tumor progression. On the other hand, methylation analysis showed that the up-regulation of EFTUD2, GAPDH, NOP56 might be due to the hypomethylation status of their promoters. Next, we investigated the correlations between the expression levels of four hub genes and tumor immune infiltration using Tumor Immune Estimation Resource (TIMER). Gene set variation analysis suggested that the four hub genes were associated with numerous pathways that affect tumor progression or immune microenvironment. Overall, our results showed that the four hub genes were closely related to tumor prognosis, and may serve as targets for treatment and diagnosis of HCC. In addition, the associations between these genes and immune infiltration enhanced our understanding of tumor immune environment and provided new directions for the development of drugs and the monitoring of tumor immune status.

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The Crosstalk Between Malignant Cells and Tumor-Promoting Immune Cells Relevant to Immunotherapy in Pancreatic Ductal Adenocarcinoma

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.821232 ◽

2022 ◽

Vol 9 ◽

Author(s):

Xuefei Liu ◽

Ziwei Luo ◽

Xuechen Ren ◽

Zhihang Chen ◽

Xiaoqiong Bao ◽

...

Keyword(s):

Pancreatic Ductal Adenocarcinoma ◽

Rna Sequencing ◽

Immune Cells ◽

Immune Checkpoint ◽

Immune Cell ◽

Immune Checkpoint Blockade ◽

Ductal Adenocarcinoma ◽

Malignant Cells ◽

Sequencing Data ◽

Immunosuppressive Microenvironment

Background: Pancreatic ductal adenocarcinoma (PDAC) is dominated by an immunosuppressive microenvironment, which makes immune checkpoint blockade (ICB) often non-responsive. Understanding the mechanisms by which PDAC forms an immunosuppressive microenvironment is important for the development of new effective immunotherapy strategies.Methods: This study comprehensively evaluated the cell-cell communications between malignant cells and immune cells by integrative analyses of single-cell RNA sequencing data and bulk RNA sequencing data of PDAC. A Malignant-Immune cell crosstalk (MIT) score was constructed to predict survival and therapy response in PDAC patients. Immunological characteristics, enriched pathways, and mutations were evaluated in high- and low MIT groups.Results: We found that PDAC had high level of immune cell infiltrations, mainly were tumor-promoting immune cells. Frequent communication between malignant cells and tumor-promoting immune cells were observed. 15 ligand-receptor pairs between malignant cells and tumor-promoting immune cells were identified. We selected genes highly expressed on malignant cells to construct a Malignant-Immune Crosstalk (MIT) score. MIT score was positively correlated with tumor-promoting immune infiltrations. PDAC patients with high MIT score usually had a worse response to immune checkpoint blockade (ICB) immunotherapy.Conclusion: The ligand-receptor pairs identified in this study may provide potential targets for the development of new immunotherapy strategy. MIT score was established to measure tumor-promoting immunocyte infiltration. It can serve as a prognostic indicator for long-term survival of PDAC, and a predictor to ICB immunotherapy response.

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Mouse Breast Carcinoma Monocytic/Macrophagic Myeloid-Derived Suppressor Cell Infiltration as a Consequence of Endothelial Dysfunction in Shb-Deficient Endothelial Cells Increases Tumor Lung Metastasis

International Journal of Molecular Sciences ◽

10.3390/ijms222111478 ◽

2021 ◽

Vol 22 (21) ◽

pp. 11478

Author(s):

Qi He ◽

Maria Jamalpour ◽

Eric Bergquist ◽

Robin L. Anderson ◽

Karin Gustafsson ◽

...

Keyword(s):

Breast Carcinoma ◽

Lung Metastasis ◽

Immune Cells ◽

Tyrosine Kinases ◽

Immune Cell ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Suppressor Cells ◽

Suppressor Cell ◽

Barrier Properties

Metastasis reflects both the inherent properties of tumor cells and the response of the stroma to the presence of the tumor. Vascular barrier properties, either due to endothelial cell (EC) or pericyte function, play an important role in metastasis in addition to the contribution of the immune system. The Shb gene encodes the Src homology-2 domain protein B that operates downstream of tyrosine kinases in both vascular and immune cells. We have investigated E0771.lmb breast carcinoma metastasis in mice with conditional deletion of the Shb gene using the Cdh5-CreERt2 transgene, resulting in inactivation of the Shb-gene in EC and some hematopoietic cell populations. Lung metastasis from orthotopic tumors, tumor vascular and immune cell characteristics, and immune cell gene expression profiles were determined. We found no increase in vascular leakage that could explain the observed increase in metastasis upon the loss of Shb expression. Instead, Shb deficiency in EC promoted the recruitment of monocytic/macrophagic myeloid-derived suppressor cells (mMDSC), an immune cell type that confers a suppressive immune response, thus enhancing lung metastasis. An MDSC-promoting cytokine/chemokine profile was simultaneously observed in tumors grown in mice with EC-specific Shb deficiency, providing an explanation for the expanded mMDSC population. The results demonstrate an intricate interplay between tumor EC and immune cells that pivots between pro-tumoral and anti-tumoral properties, depending on relevant genetic and/or environmental factors operating in the microenvironment.

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Development of an immunogenomic landscape for the competing endogenous RNAs network of peri-implantitis

BMC Medical Genetics ◽

10.1186/s12881-020-01145-4 ◽

2020 ◽

Vol 21 (1) ◽

Author(s):

Yang Li ◽

Jina Zheng ◽

Chanjuan Gong ◽

Kengfu Lan ◽

Yuqing Shen ◽

...

Keyword(s):

Immune Cells ◽

Immune Cell ◽

Profile Data ◽

Immune Microenvironment ◽

Normal Tissues ◽

Cerna Network ◽

Inflammatory Damage ◽

Competing Endogenous Rnas ◽

Immune Related Genes ◽

Important Significance

Abstract Background Peri-implantitis is an inflammation that occurs around the implant, resulting in varying degrees of inflammatory damage to the soft and hard tissues. The characteristic criterion is the loss of the supporting bone in an inflammatory environment. However, the specific mechanisms and biomarkers involved in peri-implantitis remain to be further studied. Recently, competing endogenous RNAs (ceRNA) and immune microenvironment have been found to play a more important role in the inflammatory process. In our study, we analyzed the expression of immune related microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and message RNAs (mRNAs) in peri-implantitis by analyzing GSE33774 and GSE57631. Methods In this study, we explored the expression profile data of immune-related lncRNAs, miRNAs and mRNAs, and constructed immune-related ceRNA network involved in the pathogenesis of peri-implantitis. In addition, the CIBERSORT was used to evaluate the content of immune cells in normal tissues and peri-implantitis to detect the immune microenvironment of peri-implantitis. Results In the analysis, 14 DElncRNAs, 16 DEmiRNAs, and 18 DEmRNAs were used to establish an immune related ceRNA network and the immune infiltration patterns associated with peri-implantitis was discovered. Through the mutual verification of the two datasets, we found that GSK3B and miR-1297 may have important significance in the immune microenvironment and pathogenesis of peri-implantitis and GSK3B was closely related to four types of immune cells, especially with the highest correlation with resting mast cells (P = 0.0003). Conclusions Through immune-related ceRNA network, immune-related genes (IRGs) and immune cell infiltration can further comprehensively understand the pathogenesis of peri-implantitis, which built up an immunogenomic landscape with clinical significance for peri-implantitis.

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Applications of Single-Cell Omics to Dissect Tumor Microenvironment

Frontiers in Genetics ◽

10.3389/fgene.2020.548719 ◽

2020 ◽

Vol 11 ◽

Author(s):

Tingting Guo ◽

Weimin Li ◽

Xuyu Cai

Keyword(s):

Tumor Microenvironment ◽

Single Cell ◽

Immune Cells ◽

Immune Cell ◽

Cell Types ◽

Immune Checkpoint Blockade ◽

Lineage Tracing ◽

Great Success ◽

Novel Technologies ◽

Single Cell Sequencing

The recent technical and computational advances in single-cell sequencing technologies have significantly broaden our toolkit to study tumor microenvironment (TME) directly from human specimens. The TME is the complex and dynamic ecosystem composed of multiple cell types, including tumor cells, immune cells, stromal cells, endothelial cells, and other non-cellular components such as the extracellular matrix and secreted signaling molecules. The great success on immune checkpoint blockade therapy has highlighted the importance of TME on anti-tumor immunity and has made it a prime target for further immunotherapy strategies. Applications of single-cell transcriptomics on studying TME has yielded unprecedented resolution of the cellular and molecular complexity of the TME, accelerating our understanding of the heterogeneity, plasticity, and complex cross-interaction between different cell types within the TME. In this review, we discuss the recent advances by single-cell sequencing on understanding the diversity of TME and its functional impact on tumor progression and immunotherapy response driven by single-cell sequencing. We primarily focus on the major immune cell types infiltrated in the human TME, including T cells, dendritic cells, and macrophages. We further discuss the limitations of the existing methodologies and the prospects on future studies utilizing single-cell multi-omics technologies. Since immune cells undergo continuous activation and differentiation within the TME in response to various environmental cues, we highlight the importance of integrating multimodal datasets to enable retrospective lineage tracing and epigenetic profiling of the tumor infiltrating immune cells. These novel technologies enable better characterization of the developmental lineages and differentiation states that are critical for the understanding of the underlying mechanisms driving the functional diversity of immune cells within the TME. We envision that with the continued accumulation of single-cell omics datasets, single-cell sequencing will become an indispensable aspect of the immune-oncology experimental toolkit. It will continue to drive the scientific innovations in precision immunotherapy and will be ultimately adopted by routine clinical practice in the foreseeable future.

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IMMU-01. MYELOID-DERIVED SUPPRESSOR CELL HETEROGENEITY DRIVES GLIOBLASTOMA PROGRESSION IN A SEX-DEPENDENT MANNER

Neuro-Oncology ◽

10.1093/neuonc/noz175.495 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi118-vi118

Author(s):

Defne Bayik ◽

Daniel Silver ◽

Chihyun Park ◽

Dionysios Watson ◽

Mia Sorensen ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Immune Cell ◽

Ex Vivo ◽

Suppressor Cells ◽

Suppressor Cell ◽

Fold Increase ◽

Dependent Manner ◽

Ki 67 ◽

Accumulation Pattern ◽

Therapeutic Opportunity

Abstract An immunosuppressive tumor microenvironment is a major factor facilitating glioblastoma (GBM) progression and therapeutic resistance. Immunotherapies have had variable success in improving the outcome of GBM patients, suggesting that there is a need to gain insight into the mechanisms of immunosuppression. Our group previously demonstrated that myeloid-derived suppressor cells (MDSCs) expand in GBM patients and infiltrate tumors, where they suppress the activity of cytotoxic cells. However, the mechanisms by which individual MDSC subsets promote tumorigenesis remain understudied. Using the syngeneic mouse glioma models GL261, CT-2A and SB28, we show that monocytic MDSCs (mMDSCs) are prevalent in tumors and that their frequency is significantly higher in males, who constitute 60% of GBM patients and have a worse prognosis than females. mMDSC abundance was further associated with poor survival, and male mice reached morbidity endpoint earlier. Consistent with preclinical observations, male GBM patient specimens had significantly more IBA+CD204+ immunosuppressive myeloid cells compared to female GBM tissue. In contrast, female tumor-bearing mice had a two-fold increase in circulating granulocytic MDSC (gMDSC) frequency, while this population remained unchanged in males. Female-to-male bone marrow chimeras demonstrated that intrinsic discrepancies in immune cell characteristics drive the sex differences in survival. Consistent with the differential MDSC accumulation pattern, targeting gMDSCs with anti-Ly6G neutralizing antibodies extended the lifespan of female mice without providing a survival advantage to males. However, mMDSCs were protected from the anti-Ly6C depletion strategy due to their systemic and local proliferation, as indicated by ex vivo Ki-67 staining and subsequently confirmed by gene expression analysis. Drug-prediction algorithms using the differential RNA sequencing profiles demonstrated that mMDSCs can be targeted by chemotherapeutics, while immunomodulatory drugs are effective against gMDSCs. Collectively, these findings indicate that MDSC subset variation might represent a therapeutic opportunity for improved therapeutic efficacy of immunotherapies while accounting for sex as a biological variable.

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Shear stress modulates RAGE-mediated inflammation in a model of diabetes-induced metabolic stress

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00869.2011 ◽

2012 ◽

Vol 302 (12) ◽

pp. H2498-H2508 ◽

Cited By ~ 20

Author(s):

J. Sherrod DeVerse ◽

Keith A. Bailey ◽

Kaleena N. Jackson ◽

Anthony G. Passerini

Keyword(s):

Shear Stress ◽

Inflammatory Responses ◽

Advanced Glycation Endproducts ◽

Metabolic Stress ◽

High Mobility ◽

Dependent Manner ◽

Direct Role ◽

Arterial Hemodynamics ◽

Tnf Α ◽

Rage Expression

Atherosclerosis occurs preferentially at sites of disturbed blood flow despite the influence of risk factors contributing to systemic inflammation. The receptor for advanced glycation endproducts (RAGE) is a prominent mediator of inflammation in diabetes that is upregulated in atherosclerotic plaques. Our goal was to elucidate a role for arterial hemodynamics in the regulation of RAGE expression and activity. Endothelial RAGE expression was elevated at sites of flow disturbance in the aortas of healthy swine. To demonstrate a direct role for physiological shear stress (SS) in modulating RAGE expression, human aortic endothelial cells (HAEC) were exposed to high SS (HSS; 15 dyn/cm2), which downregulated RAGE by fourfold, or oscillatory SS (OSS; 0 ± 5 dyn/cm2), which upregulated RAGE by threefold, compared with static culture at 4 h. In a model of diabetes-induced metabolic stress, HAEC were chronically conditioned under high glucose (25 mM) and then simultaneously stimulated with TNF-α (0.5 ng/ml) and the RAGE ligand high mobility group box 1 (HMGB1). A 50% increase in VCAM-1 expression over TNF-α was associated with increased cytoplasmic and mitochondrial reactive oxygen species and NF-κB activity. This increase was RAGE-specific and NADPH oxidase dependent. In activated HAEC, OSS amplified HMGB1-induced VCAM-1 (3-fold) and RAGE (1.6-fold) expression and proportionally enhanced monocyte adhesion to HAEC in a RAGE-dependent manner, while HSS mitigated these increases to the level of TNF-α alone. We demonstrate that SS plays a fundamental role in regulating RAGE expression and inflammatory responses in the endothelium. These findings may provide mechanistic insight into how diabetes accelerates the nonrandom distribution of atherosclerosis in arteries.

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Adipose Tissue in Obesity-Related Inflammation and Insulin Resistance: Cells, Cytokines, and Chemokines

ISRN Inflammation ◽

10.1155/2013/139239 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 385

Author(s):

Kassem Makki ◽

Philippe Froguel ◽

Isabelle Wolowczuk

Keyword(s):

Insulin Resistance ◽

Adipose Tissue ◽

Immune Cells ◽

Metabolic Regulation ◽

Immune Cell ◽

Suppressor Cells ◽

Cell Types ◽

Immune Functions ◽

Cytokines And Chemokines ◽

Wide Range

Adipose tissue is a complex organ that comprises a wide range of cell types with diverse energy storage, metabolic regulation, and neuroendocrine and immune functions. Because it contains various immune cells, either adaptive (B and T lymphocytes; such as regulatory T cells) or innate (mostly macrophages and, more recently identified, myeloid-derived suppressor cells), the adipose tissue is now considered as a bona fide immune organ, at the cross-road between metabolism and immunity. Adipose tissue disorders, such as those encountered in obesity and lipodystrophy, cause alterations to adipose tissue distribution and function with broad effects on cytokine, chemokine, and hormone expression, on lipid storage, and on the composition of adipose-resident immune cell populations. The resulting changes appear to induce profound consequences for basal systemic inflammation and insulin sensitivity. The purpose of this review is to synthesize the current literature on adipose cell composition remodeling in obesity, which shows how adipose-resident immune cells regulate inflammation and insulin resistance—notably through cytokine and chemokine secretion—and highlights major research questions in the field.

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