An NK-like CAR T cell transition in CAR T cell dysfunction.

Chimeric antigen receptor (CAR) T cell therapy has achieved remarkable success in hematological malignancies but remains ineffective in solid tumors, due in part to CAR T cell exhaustion in the solid tumor microenvironment. To study dysfunction of mesothelin-redirected CAR T cells in pancreatic cancer, we establish a robust model of continuous antigen exposure that recapitulates hallmark features of T cell exhaustion and discover, both in vitro and in CAR T cell patients, that CAR dysregulation is associated with a CD8+ T-to-NK-like T cell transition. Furthermore, we identify a gene signature defining CAR and TCR dysregulation and transcription factors, including SOX4 and ID3 as key regulators of CAR T cell exhaustion. Our findings shed light on the plasticity of human CAR T cells and demonstrate that genetic downmodulation of ID3 and SOX4 expression can improve the efficacy of CAR T cell therapy in solid tumors by preventing or delaying CAR T cell dysfunction.

Stellate Cells, Hepatocytes, and Endothelial Cells Imprint the Kupffer Cell Identity on Monocytes Colonizing the Liver Macrophage Niche.

Macrophages are strongly adapted to their tissue of residence. Yet, little is known about the cell-cell interactions that imprint the tissue-specific identities of macrophages in their respective niches. Using conditional depletion of liver Kupffer cells, we traced the developmental stages of monocytes differentiating into Kupffer cells and mapped the cellular interactions imprinting the Kupffer cell identity. Kupffer cell loss induced tumor necrosis factor (TNF)- and interleukin-1 (IL-1) receptor-dependent activation of stellate cells and endothelial cells, resulting in the transient production of chemokines and adhesion molecules orchestrating monocyte engraftment. Engrafted circulating monocytes transmigrated into the perisinusoidal space and acquired the liver-associated transcription factors inhibitor of DNA 3 (ID3) and liver X receptor-α (LXR-α). Coordinated interactions with hepatocytes induced ID3 expression, whereas endothelial cells and stellate cells induced LXR-α via a synergistic NOTCH-BMP pathway. This study shows that the Kupffer cell niche is composed of stellate cells, hepatocytes, and endothelial cells that together imprint the liver-specific macrophage identity.

ID3 is a novel target gene of p53 and modulates lung cancer cell metastasis.

The tumor suppressor p53 prevents cancer development by regulating dozens of target genes with diverse biological functions. Although numerous p53 target genes have been identified to date, the dynamics and function of the regulatory network centered on p53 have not yet been fully elucidated. We herein identified inhibitor of DNA-binding/differentiation-3 (ID3) as a direct p53 target gene. p53 bound the distal promoter of ID3 and positively regulated its transcription. ID3 expression was significantly decreased in clinical lung cancer tissues, and was closely associated with overall survival outcomes in these patients. Functionally, ID3 deficiency promoted the metastatic ability of lung cancer cells through its effects on the transcriptional regulation of CDH1. Furthermore, the ectopic expression of ID3 in p53-knockdown cells restored E-cadherin expression. Collectively, the present results demonstrate that ID3 plays a tumor-suppressive role as a downstream effector of p53 and impedes lung cancer cell metastasis by regulating E-cadherin expression.

Strong Activation of ID1, ID2, and ID3 Genes Is Coupled with the Formation of Vasculogenic Mimicry Phenotype in Melanoma Cells.

Gene expression patterns are very sensitive to external influences and are reflected in phenotypic changes. It was previously described that transferring melanoma cells from a plastic surface to Matrigel led to formation of de novo vascular networks-vasculogenic mimicry-that are characteristic to a stemness phenotype in aggressive tumors. Up to now there was no detailed data about the gene signature accompanying this process. Here, we show that this transfer shortly led to extremely strong epigenetic changes in gene expression in the melanoma cells. We observed that on Matrigel numerous genes controlling ribosome biogenesis were upregulated. However, most of the activated genes were inhibitors of the differentiation genes (ID1, ID2, and ID3). At the same time, the genes that control differentiation were downregulated. Both the upregulated and the downregulated genes are simultaneously targeted by different transcription factors shaping sets of co-expressed genes. The specific group of downregulated genes shaping contacts with rDNA genes are also associated with the H3K27me3 mark and with numerous lincRNAs and miRNAs. We conclude that the stemness phenotype of melanoma cells is due to the downregulation of developmental genes and formation of dedifferentiated cells.

Quantitative classification of chromatin dynamics reveals regulators of intestinal stem cell differentiation.

Intestinal stem cell (ISC) plasticity is thought to be regulated by broadly permissive chromatin shared between ISCs and their progeny. Here, we have used a Sox9EGFP reporter to examine chromatin across ISC differentiation. We find that open chromatin regions (OCRs) can be defined as broadly permissive or dynamic in a locus-specific manner, with dynamic OCRs found primarily in loci consistent with distal enhancers. By integrating gene expression with chromatin accessibility at transcription factor (TF) motifs in the context of Sox9EGFP populations, we classify broadly permissive and dynamic chromatin relative to TF usage. These analyses identify known and potential regulators of ISC differentiation via association with dynamic changes in chromatin. Consistent with computational predictions, Id3-null mice exhibit increased numbers of cells expressing the ISC-specific biomarker OLFM4. Finally, we examine the relationship between gene expression and 5-hydroxymethylcytosine (5hmC) in Sox9EGFP populations, which reveals 5hmC enrichment in absorptive lineage-specific genes. Our data demonstrate that intestinal chromatin dynamics can be quantitatively defined in a locus-specific manner, identify novel potential regulators of ISC differentiation and provide a chromatin roadmap for further dissecting cis regulation of cell fate in the intestine.

A positive feedback loop between ID3 and PPARγ via DNA damage repair regulates the efficacy of radiotherapy for rectal cancer.

OBJECTIVE: To study the effect of inhibitor of differentiation 3 (ID3) on radiotherapy in patients with rectal cancer and to explore its primary mechanism. METHODS: Cell proliferation and clonogenic assays were used to study the relationship between ID3 and radiosensitivity. Co-immunoprecipitation and immunofluorescence were performed to analyze the possible mechanism of ID3 in the radiosensitivity of colorectal cancer. At the same time, a xenograft tumor model of HCT116 cells in nude mice was established to study the effect of irradiation on the tumorigenesis of ID3 knockdown colorectal cancer cells in vivo. Immunohistochemistry was performed to analyze the relationship between ID3 expression and the efficacy of radiotherapy in 46 patients with rectal cancer. RESULTS: Proliferation and clonogenic assays revealed that the radiosensitivity of colorectal cancer cells decreased with ID3 depletion through p53-independent pathway. With the decrease in ID3 expression, MDC1 was downregulated. Furthermore, the expression of ID3, MDC1, and γH2AX increased and formed foci after irradiation. ID3 interacted with PPARγ and form a positive feedback loop to enhance the effect of ID3 on the radiosensitivity of colorectal cancer. Irradiation tests in nude mice also confirmed that HCT116 cells with ID3 knockdown were more affected by irradiation. Immunohistochemical study showed that rectal cancer patients with low expression of ID3 had better radiotherapy efficacy. CONCLUSIONS: ID3 and PPARγ influence the radiosensitivity of colorectal cancer cells by interacting with MDC1 to form a positive feedback loop that promotes DNA damage repair. Patients with low expression of ID3 who received neoadjuvant chemoradiotherapy can obtain a better curative effect.

Corneal fibrosis abrogation by a localized AAV-mediated inhibitor of differentiation 3 (Id3) gene therapy in rabbit eyes in vivo.

Previously we found that inhibitor of differentiation 3 (Id3) gene, a transcriptional repressor, efficiently inhibits corneal keratocyte differentiation to myofibroblasts in vitro. This study evaluated the potential of adeno-associated virus 5 (AAV5)-mediated Id3 gene therapy to treat corneal scarring using an established rabbit in vivo disease model. Corneal scarring/fibrosis in rabbit eyes was induced by alkali trauma, and 24 h thereafter corneas were administered with either balanced salt solution AAV5-naked vector, or AAV5-Id3 vector (n = 6/group) via an optimized reported method. Therapeutic effects of AAV5-Id3 gene therapy on corneal pathology and ocular health were evaluated with clinical, histological, and molecular techniques. Localized AAV5-Id3 gene therapy significantly inhibited corneal fibrosis/haze clinically from 2.7 to 0.7 on the Fantes scale in live animals (AAV5-naked versus AAV5-Id3; p < 0.001). Furthermore, AAV5-Id3 treatment significantly reduced profibrotic gene mRNA levels: α-smooth muscle actin (α-SMA) (2.8-fold; p < 0.001), fibronectin (3.2-fold; p < 0.001), collagen I (0.8-fold; p < 0.001), and collagen III (1.4-fold; p < 0.001), as well as protein levels of α-SMA (23.8%; p < 0.001) and collagens (1.8-fold; p < 0.001). The anti-fibrotic activity of AAV5-Id3 is attributed to reduced myofibroblast formation by disrupting the binding of E-box proteins to the promoter of α-SMA, a transforming growth factor-ß signaling downstream target gene. In conclusion, these results indicate that localized AAV5-Id3 delivery in stroma caused no clinically relevant ocular symptoms or corneal cellular toxicity in the rabbit eyes.

MicroRNA-24-3p promotes skeletal muscle differentiation and regeneration by regulating HMGA1.

Numerous studies have established the critical roles of microRNAs in regulating post-transcriptional gene expression in diverse biological processes. Here, we report on the role and mechanism of miR-24-3p in skeletal muscle differentiation and regeneration. miR-24-3p promotes myoblast differentiation and skeletal muscle regeneration by directly targeting high mobility group AT-hook 1 (HMGA1) and regulating it and its direct downstream target, the inhibitor of differentiation 3 (ID3). miR-24-3p knockdown in neonatal mice increases PAX7-positive proliferating muscle stem cells (MuSCs) by derepressing Hmga1 and Id3. Similarly, inhibition of miR-24-3p in the tibialis anterior muscle prevents Hmga1 and Id3 downregulation and impairs regeneration. These findings provide evidence that the miR-24-3p/HMGA1/ID3 axis is required for MuSC differentiation and skeletal muscle regeneration in vivo.

A mosaic analysis system with Cre or Tomato expression in the mouse.

Somatic mutations are major genetic contributors to cancers and many other age-related diseases. Many disease-causing somatic mutations can initiate clonal growth prior to the appearance of any disease symptoms, yet experimental models that can be used to examine clonal abnormalities are limited. We describe a mosaic analysis system with Cre or Tomato (MASCOT) for tracking mutant cells and demonstrate its utility for modeling clonal hematopoiesis. MASCOT can be induced to constitutively express either Cre-GFP or Tomato for lineage tracing of a mutant and a reference group of cells simultaneously. We conducted mosaic analysis to assess functions of the Id3 and/or Tet2 gene in hematopoietic cell development and clonal hematopoiesis. Using Tomato-positive cells as a reference population, we demonstrated the high sensitivity of this system for detecting cell-intrinsic phenotypes during short-term or long-term tracking of hematopoietic cells. Long-term tracking of Tet2 mutant or Tet2/Id3 double-mutant cells in our MASCOT model revealed a dynamic shift from myeloid expansion to lymphoid expansion and subsequent development of lymphoma. This work demonstrates the utility of the MASCOT method in mosaic analysis of single or combined mutations, making the system suitable for modeling somatic mutations identified in humans.

Comprehensive analysis of ID genes reveals the clinical and prognostic value of ID3 expression in acute myeloid leukemia using bioinformatics identification and experimental validation.

BACKGROUND: Dysregulation of inhibitor of differentiation/DNA binding (ID) genes is linked to cancer growth, angiogenesis, invasiveness, metastasis and patient survival. Nevertheless, few investigations have systematically determined the expression and prognostic value of ID genes in acute myeloid leukemia (AML). METHODS: The expression and clinical prognostic value of ID genes in AML were first identified by public databases and further validated by our research cohort. RESULTS: Using public data, the expression of ID1/ID3 was markedly downregulated in AML, and the expression of ID2 was greatly upregulated in AML, whereas ID4 showed no significant difference. Among the ID genes, only ID3 expression may be the most valuable prognostic biomarker in both total AML and cytogenetically normal AML (CN-AML) and especially in CN-AML. Clinically, reduced ID3 expression was greatly associated with higher white blood cell counts, peripheral blood/bone marrow blasts, normal karyotypes and intermediate cytogenetic risk. In addition, low ID3 expression was markedly related to FLT3 and NPM1 mutations as well as wild-type TP53. Despite these associations, multivariate Cox regression analysis revealed that ID3 expression was an independent risk factor affecting overall survival (OS) and disease free survival (DFS) in CN-AML patients. Biologically, a total of 839 mRNAs/lncRNAs and 72 microRNAs were found to be associated with ID3 expression in AML. Importantly, the expression of ID3 with discriminative value in AML was further confirmed in our research cohort. CONCLUSION: The bioinformatics analysis and experimental verification demonstrate that low ID3 expression independently affects OS and DFS in patients with CN-AML, which might be seen as a potential prognostic indicator in CN-AML.

Id(entifying) the inhibitor of DNA binding 3 in the brain of Nothobranchius furzeri upon aging.

Inhibitors of DNA (Id) are key transcription factors (TFs) regulating neurogenic processes. They belong to the helix-loop-helix (HLH) TF family and are dominant negative regulators of basic HLH proteins (bHLHs). Specifically, they inhibit cell differentiation and enhance cell proliferation and motility. The Id family includes four members, Id1, Id2, Id3, and Id4, which have been identified in nearly all vertebrates. The transcript catalog of the African turquoise killifish, Nothobranchius furzeri, contains all four TFs and has evolved showing positive selection for Id3. N. furzeri, a teleost, is the short-lived vertebrate and is gaining increasing scientific interest as a new model organism in aging research. It is characterized by embryonic diapause, explosive sexual maturation, and rapid aging. In this study, we investigated both the expression and the role of Id3 in the brain of this model organism. Interestingly, Id3 was upregulated age-dependently along with a distribution pattern resembling that of other vertebrates. Additionally, the gene has undergone positive selection during evolution and shows a high degree of conservation relative to that of other vertebrates. These features make N. furzeri a valid tool for aging studies and a potential model in translational research.

EGF stimulates human trophoblast cell invasion by downregulating ID3-mediated KISS1 expression.

BACKGROUND: During pregnancy, trophoblast cell invasion needs to be finely controlled. Aberrant trophoblast cell invasion is associated with placental diseases. Epidermal growth factor (EGF) and its receptor, EGFR, are expressed in trophoblast cells. Although the pro-invasive effect of EGF on trophoblast cells has been reported, the underlying mechanism remains largely unknown. RESULTS: In the present study, we conducted an RNA sequencing (RNA-seq) to HTR-8/SVneo human trophoblast cells in response to EGF and identified KISS1 as a target gene of EGF. The human KISS1 gene encodes kisspeptin, also known as metastin, which can suppress tumor metastasis. Our results showed that EGF treatment downregulated KISS1 expression and secretion by activating the EGFR-mediated PI3K/AKT signaling pathway. In addition, the expression of inhibitor of DNA-binding protein 3 (ID3) was downregulated by EGF and that was required for the EGF-suppressed KISS1 expression. Functionally, transwell invasion assays demonstrated that EGF stimulated human trophoblast cell invasion by downregulating KISS1 expression. Preeclampsia (PE) is a placental disease characterized by insufficient trophoblast cell invasion. Our clinical results revealed that serum levels of EGF were downregulated while serum and placental levels of KISS1 were upregulated in PE patients. CONCLUSIONS: This study demonstrates that downregulation of EGF can lead to poor trophoblast cell invasion by increasing KISS1 expression which subsequently contributes to the pathogenesis of PE. Video Abstract.

Blocking COX-2 induces apoptosis and inhibits cell proliferation via the Akt/survivin- and Akt/ID3 pathway in low-grade-glioma.

Approximately half of surgically-treated patients with low-grade-glioma (LGG) suffer recurrence or metastasis. Currently there is no effective drug treatment. While the selective COX-2 inhibitor celecoxib showed anti-neoplastic activity against several malignant tumors, its effects against LGG remain to be elucidated. Ours is the first report that the expression level of COX-2 in brain tissue samples from patients with LGG and in LGG cell lines is higher than in the non-neoplastic region and in normal brain cells. We found that celecoxib attenuated LGG cell proliferation in a dose-dependent manner. It inhibited the generation of prostaglandin E2 and induced apoptosis and cell-cycle arrest. We also show that celecoxib hampered the activation of the Akt/survivin- and the Akt/ID3 pathway in LGGs. These findings suggest that celecoxib may have a promising therapeutic potential and that the early treatment of LGG patients with the drug may be beneficial.

The Proto-oncogene Transcription Factor Ets1 Regulates Neural Crest Development through Histone Deacetylase 1 to Mediate Output of Bone Morphogenetic Protein Signaling.

The neural crest (NC) is a transient, migratory cell population that differentiates into a large variety of tissues including craniofacial cartilage, melanocytes, and peripheral nervous system. NC is initially induced at the border of neural plate and non-neural ectoderm by balanced regulation of multiple signaling pathways among which an intermediate bone morphogenetic protein (BMP) signaling is essential for NC formation. ets1, a proto-oncogene playing important roles in tumor invasion, has also been implicated in delamination of NC cells. In this study, we investigated Ets1 function in NC formation using Xenopus. Overexpression of ets1 repressed NC formation through down-regulation of BMP signaling. Moreover, ets1 repressed the BMP-responsive gene id3 that is essential for NC formation. Conversely, overexpression of id3 can partially rescue the phenotype of NC inhibition induced by ectopic ets1. Mechanistically, we found that Ets1 binds to id3 promoter as well as histone deacetylase 1, suggesting that Ets1 recruits histone deacetylase 1 to the promoter of id3, thereby inducing histone deacetylation of the id3 promoter. Thus, our studies indicate that Ets1 regulates NC formation through attenuating BMP signaling epigenetically.

Genetic differences between paediatric and adult Burkitt lymphomas.

Dysregulation of MYC is the genetic hallmark of Burkitt lymphoma (BL) but it is encountered in other aggressive mature B-cell lymphomas. MYC dysregulation needs other cooperating events for BL development. We aimed to characterize these events and assess the differences between adult and paediatric BLs that may explain the different outcomes in these two populations. We analysed patterns of genetic aberrations in a series of 24 BLs: 11 adults and 13 children. We looked for genomic imbalances (copy number variations), copy-neutral loss of heterozygosity (CN-LOH) and mutations in TP53, CDKN2A, ID3 (exon 1), TCF3 (exon17) and CCND3 (exon 6). Young patients displayed more frequent 13q31.3q32.1 amplification, 7q32q36 gain and 5q23.3 CN-LOH, while 17p13 and 18q21.3 CN-LOH were only detected in adult BLs. ID3 mutations were present in all adult samples, but only in 42% of childhood cases. CCND3 and ID3 double-hit mutations, as well as 18q21 CN-LOH, seemed to be associated with poorer outcome. For the first time, we report different genetic anomalies between adult and paediatric BLs, suggesting age-related heterogeneity in Burkitt lymphomagenesis. This may explain the poorer prognosis of adult BLs. Additional studies are needed to confirm these results in the setting of clinical trials.

Role of helical constraints of the EBS1-IBS1 duplex of a group II intron on demarcation of the 5' splice site.

Recognition of the 5' splice site by group II introns involves pairing between an exon binding sequence (EBS) 1 within the ID3 stem-loop of domain 1 and a complementary sequence at the 3' end of exon 1 (IBS1). To identify the molecular basis for splice site definition of a group IIB ai5γ intron, we probed the solution structure of the ID3 stem-loop alone and upon binding of its IBS1 target by solution NMR. The ID3 stem was structured. The base of the ID3 loop was stacked but displayed a highly flexible EBS1 region. The flexibility of EBS1 appears to be a general feature of the ai5γ and the smaller Oceanobacillus iheyensis (O.i.) intron and may help in effective search of conformational space and prevent errors in splicing as a result of fortuitous base-pairing. Binding of IBS1 results in formation of a structured seven base pair duplex that terminates at the 5' splice site in spite of the potential for additional A-U and G•U pairs. Comparison of these data with conformational features of EBS1-IBS1 duplexes extracted from published structures suggests that termination of the duplex and definition of the splice site are governed by constraints of the helical geometry within the ID3 loop. This feature and flexibility of the uncomplexed ID3 loop appear to be common for both the ai5γ and O.i. introns and may help to fine-tune elements of recognition in group II introns.

Inflammation-induced S100A8 activates Id3 and promotes colorectal tumorigenesis.

The aberrant expression of S100A8 and S100A9 is linked to nonresolving inflammation and ultimately to carcinogenesis, whereas the underlying mechanism that allows inflammation to progress to specific cancer types remains unknown. Here, we report that S100A8 was induced by inflammation and then promoted colorectal tumorigenesis downstream by activating Id3 (inhibitor of differentiation 3). Using gene expression profiling and immunohistochemistry, we found that both S100A8 and S100A9 were upregulated in the chemically-induced colitis-associated cancer mouse model and in human colorectal cancer specimens. Furthermore, we showed that S100A8 and S100A9 acted as chemoattractant proteins by recruiting macrophages, promoting the proliferation and invasion of colon cancer cell, as well as spurring the cycle that culminates in the acceleration of cancer metastasis in a nude mouse model. S100A8 regulated colon cancer cell cycle and proliferation by inducing Id3 expression while inhibiting p21. Id3 expression was regulated by Smad5, which was directly phosphorylated by Akt1. Our study revealed a novel mechanism in which inflammation-induced S100A8 promoted colorectal tumorigenesis by acting upstream to activate the Akt1-Smad5-Id3 axis.

ID3 contributes to the acquisition of molecular stem cell-like signature in microvascular endothelial cells: its implication for understanding microvascular diseases.

While significant progress has been made to advance our knowledge of microvascular lesion formation, yet the investigation of how stem-like cells may contribute to the pathogenesis of microvascular diseases is still in its infancy. We assessed whether the inhibitor of DNA binding and differentiation 3 (ID3) contributes to the acquisition of a molecular stem cell-like signature in microvascular endothelial cells. The effects of stable ID3 overexpression and SU5416 treatment - a chemical inducer of microvascular lesions, had on the stemness signature were determined by flow cytometry, immunoblot, and immunohistochemistry. Continuous ID3 expression produced a molecular stemness signature consisting of CD133(+) VEGFR3(+) CD34(+) cells. Cells exposed to SU5416 showed positive protein expression of ID3, VEGFR3, CD34 and increased expression of pluripotent transcription factors Oct-4 and Sox-2. ID3 overexpressing cells supported the formation of a 3-D microvascular lesion co-cultured with smooth muscle cells. In addition, in vivo microvascular lesions from SuHx rodent model showed an increased expression of ID3, VEGFR3, and Pyk2 similar to SU5416 treated human endothelial cells. Further investigations into how normal and stem-like cells utilize ID3 may open up new avenues for a better understanding of the molecular mechanisms which are underlying the pathological development of microvascular diseases.

Ankyrin repeat domain protein 2 and inhibitor of DNA binding 3 cooperatively inhibit myoblast differentiation by physical interaction.

Ankyrin repeat domain protein 2 (ANKRD2) translocates from the nucleus to the cytoplasm upon myogenic induction. Overexpression of ANKRD2 inhibits C2C12 myoblast differentiation. However, the mechanism by which ANKRD2 inhibits myoblast differentiation is unknown. We demonstrate that the primary myoblasts of mdm (muscular dystrophy with myositis) mice (pMB(mdm)) overexpress ANKRD2 and ID3 (inhibitor of DNA binding 3) proteins and are unable to differentiate into myotubes upon myogenic induction. Although suppression of either ANKRD2 or ID3 induces myoblast differentiation in mdm mice, overexpression of ANKRD2 and inhibition of ID3 or vice versa is insufficient to inhibit myoblast differentiation in WT mice. We identified that ANKRD2 and ID3 cooperatively inhibit myoblast differentiation by physical interaction. Interestingly, although MyoD activates the Ankrd2 promoter in the skeletal muscles of wild-type mice, SREBP-1 (sterol regulatory element binding protein-1) activates the same promoter in the skeletal muscles of mdm mice, suggesting the differential regulation of Ankrd2. Overall, we uncovered a novel pathway in which SREBP-1/ANKRD2/ID3 activation inhibits myoblast differentiation, and we propose that this pathway acts as a critical determinant of the skeletal muscle developmental program.

The potential role of inhibitor of differentiation-3 in human adipose tissue remodeling and metabolic health.

Metabolic health in obesity is known to differ among individuals, and the distribution of visceral (VAT) and subcutaneous adipose tissue (SAT) plays an important role in this regard. Adipose tissue expansion is dependent on new blood vessel formation in order to prevent hypoxia and inflammation in the tissue. Regulation of angiogenesis in SAT and VAT in response to diet is therefore crucial for the metabolic outcome in obesity. Knowledge about the underlying genetic mechanisms determining metabolic health in obesity is very limited. We aimed to review the literature of the inhibitor of differentiation-3 (ID3) gene in relation to adipose tissue and angiogenesis in humans in order to determine whether ID3 could be involved in the regulation of adipose tissue expansion and metabolic health in human obesity. We find evidence that ID3 is involved in regulatory mechanisms in adipose tissue and regulates angiogenesis in many tissues including adipose tissue. We discuss how this might influence obesity and metabolic health in obesity and further discuss some potential mechanisms by which ID3 might regulate visceral and subcutaneous adipose tissue expansion. The combined results from the reviewed literature suggest ID3 to play a potential role in the underlying regulatory mechanisms of metabolic health in human obesity. The literature is still sparse and further studies focusing on human ID3 in relation to the nature of obesity are warranted.