Elevated IGF2 prevents leptin induction and terminal adipocyte differentiation in hemangioma stem cells

KLF2 Orchestrates Pathological Progression of Infantile Hemangioma through Hemangioma Stem Cell Fate Decisions

Infantile hemangioma (IH) is the most prevalent vascular tumor during infancy, characterized by a rapid proliferation phase of disorganized blood vessels and spontaneous involution. IH possibly arises from a special type of multipotent stem cells called hemangioma stem cells (HemSCs), which could differentiate into endothelial cells, pericytes, and adipocytes. However, the underlying mechanisms that regulate the cell fate determination of HemSCs remain elusive. In this study, we unveil KLF2 as a candidate transcription factor involved in the control of HemSCs differentiation. KLF2 exhibits high expression in endothelial cells in proliferating IH but diminishes in adipocytes in involuting IH. Using a combination of in vitro culture of patient-derived HemSCs and HemSCs implantation mouse models, we show that KLF2 governs the proliferation, apoptosis, and cell cycle progression of HemSCs. Importantly, KLF2 acts as a crucial determinant of HemSC fate, directing their differentiation toward endothelial cells while inhibiting adipogenesis. Knockdown of KLF2 induces a proadipogenic transcriptome in HemSCs, leading to impaired blood vessel formation and accelerated adipocyte differentiation. Collectively, our findings highlight KLF2 as a critical regulator controlling the progression and involution of IH by modulating HemSC fate decisions.

Cell Fate Regulation During the Development of Infantile Hemangioma

As the most common benign vascular tumor in infants, infantile hemangioma (IH) is characterized by rapid growth and vasculogenesis early in infancy, followed by spontaneous involution into fibrofatty tissues over time. Extensive evidence suggests that IH originates from hemangioma stem cells (HemSCs), a group of stem cells with clonal expansion and multi-directional differentiation capacity. However, the intricate mechanisms governing the cell fate transition of HemSCs during IH development remain elusive. Here we comprehensively examine the cellular composition of IH, emphasizing the nuanced properties of various IH cell types and their correlation with the clinical features of the tumor. We also summarize the current understanding of the regulatory pathways directing HemSC differentiation into endothelial cells (ECs), pericytes, and adipocytes throughout the stages of IH progression and involution. Furthermore, we discuss recent advances in unraveling the transcriptional and epigenetic regulation of EC and adipocyte development under physiological conditions, which offer crucial perspectives for understanding IH pathogenesis.

Hemangioma Endothelial Cells and Hemangioma Stem Cells in Infantile Hemangioma

BACKGROUND

Hemangioma is one of the most common benign tumors in infants and young children. The 2 most important cells in the course of infantile hemangioma (IH) are hemangioma stem cells (HemSCs) and hemangioma endothelial cells (HemECs). Infantile hemangioma is characterized by massive proliferation of HemECs, but current studies indicate that HemSCs play an important role in pathogenesis of IH.

OBJECTIVE

This review aimed to identify molecules that influence HemSC differentiation and HemEC proliferation and apoptosis to help clarify the pathogenesis of IH and provide novel drug targets for the treatment of IH.

METHODS

Relevant basic science studies related to IH were identified by searching Google Scholar, Embase, PubMed, MEDLINE, and peer-reviewed journal articles.

RESULT

Hemangioma stem cells can differentiate into HemECs, pericytes, and adipocytes. In the proliferating phase of IH, HemSCs mainly differentiate into HemECs and pericytes to promote angiogenesis. In the regressive phase, they mainly differentiate into adipocytes. Therefore, increasing the proportion of HemSCs differentiating into adipocytes, inhibiting the proliferation of HemECs, and promoting the apoptosis of HemECs can facilitate the regression of IH.

FTO and PLAG1 Genes Expression and FTO Methylation Predict Changes in Circulating Levels of Adipokines and Gastrointestinal Peptides in Children

Adipokines and gastrointestinal tract hormones are important metabolic parameters, and both epigenetic factors and differential gene expression patterns may be associated with the alterations in their concentrations in children. The function of the FTO gene (FTO alpha-ketoglutarate dependent dioxygenase) in the regulation of the global metabolic rate is well described, whereas the influence of protooncogene PLAG1 (PLAG1 zinc finger) is still not fully understood. A cross-sectional study on a group of 26 children with various BMI values (15.3–41.7; median 28) was carried out. The aim was to evaluate the dependencies between the level of methylation and expression of aforementioned genes with the concentration of selected gastrointestinal tract hormones and adipokines in children. Expression and methylation were measured in peripheral blood mononuclear DNA by a microarray technique and a restriction enzyme method, respectively. All peptide concentrations were determined using the enzyme immunoassay method. The expression level of both FTO and PLAG1 genes was statistically significantly related to the concentration of adipokines: negatively for apelin and leptin receptor, and positively for leptin. Furthermore, both FTO methylation and expression negatively correlated with the concentration of resistin and visfatin. Cholecystokinin was negatively correlated, whereas fibroblast growth factor 21 positively correlated with methylation and expression of the FTO gene, while FTO and PLAG1 expression was negatively associated with the level of cholecystokinin and glucagon-like peptide-1. The PLAG1 gene expression predicts an increase in leptin and decrease in ghrelin levels. Our results indicate that the FTO gene correlates with the concentration of hormones produced by the adipose tissue and gastrointestinal tract, and PLAG1 gene may be involved in adiposity pathogenesis. However, the exact molecular mechanisms still need to be clarified.

Adipocyte precursor cells from first degree relatives of type 2 diabetic patients feature changes in hsa-mir-23a-5p, -193a-5p, and -193b-5p and insulin-like growth factor 2 expression

First-degree relatives (FDRs) of type 2 diabetics (T2D) feature dysfunction of subcutaneous adipose tissue (SAT) long before T2D onset. miRNAs have a role in adipocyte precursor cells (APC) differentiation and in adipocyte identity. Thus, impaired miRNA expression may contribute to SAT dysfunction in FDRs. In the present work, we have explored changes in miRNA expression associated with T2D family history which may affect gene expression in SAT APCs from FDRs. Small RNA-seq was performed in APCs from healthy FDRs and matched controls and omics data were validated by qPCR. Integrative analyses of APC miRNome and transcriptome from FDRs revealed down-regulated hsa-miR-23a-5p, -193a-5p and -193b-5p accompanied by up-regulated Insulin-like Growth Factor 2 (IGF2) gene which proved to be their direct target. The expression changes in these marks were associated with SAT adipocyte hypertrophy in FDRs. APCs from FDRs further demonstrated reduced capability to differentiate into adipocytes. Treatment with IGF2 protein decreased APC adipogenesis, while over-expression of hsa-miR-23a-5p, -193a-5p and -193b-5p enhanced adipogenesis by IGF2 targeting. Indeed, IGF2 increased the Wnt Family Member 10B gene expression in APCs. Down-regulation of the three miRNAs and IGF2 up-regulation was also observed in Peripheral Blood Leukocytes (PBLs) from FDRs. In conclusion, APCs from FDRs feature a specific miRNA/gene profile, which associates with SAT adipocyte hypertrophy and appears to contribute to impaired adipogenesis. PBL detection of this profile may help in identifying adipocyte hypertrophy in individuals at high risk of T2D.

An lncRNA‑miRNA‑mRNA ceRNA network for adipocyte differentiation from human adipose‑derived stem cells

Human adipose tissue‑derived stromal stem cells (HASCs) represent a promising regenerative resource for breast reconstruction and augmentation. However, the mechanisms involved in inducing its adipogenic differentiation remain to be fully elucidated. The present study aimed to comprehensively investigate the expression changes in mRNAs, microRNAs (miRNAs) and long non‑coding (lnc)RNAs during the adipogenic differentiation of HASCs, and screen crucial lncRNA‑miRNA‑mRNA interaction axes using microarray datasets GSE57593, GSE25715 and GSE61302 collected from the Gene Expression Omnibus database. Following pretreatment, differentially expressed genes (DEGs), miRNAs (DE‑miRNAs) or lncRNAs (DE‑lncRNAs) between undifferentiated and differentiated HASCs were identified using the Linear Models for Microarray data method. A protein‑protein interaction (PPI) network was constructed for the DEGs based on protein databases, followed by module analysis. The 'lncRNA‑miRNA‑mRNA' competing endogenous RNA (ceRNA) network was constructed based on the interactions between miRNAs and mRNAs, lncRNAs and miRNAs predicted by the miRWalk and lnCeDB databases. The underlying functions of mRNAs were predicted using the clusterProfiler package. In the present study, 905 DEGs, 36 DE‑miRNAs and 577 DE‑lncRNAs were screened between undifferentiated HASCs and differentiated adipocyte cells. PPI network analysis demonstrated that LEP may be a hub gene, which was also enriched in significant module 5. LEP was predicted to be involved in the Janus kinase‑signal transducer and activator of transcription signaling pathway, and the regulation of inflammatory response. The upregulation of LEP was regulated by downregulated hsa‑miRNA (miR)‑130b‑5p and hsa‑miR‑23a‑5p (or hsa‑miR‑302d‑3p). These miRNAs also respectively interacted with RP11‑552F3.9 (or RP11‑15A1.7), ultimately forming the ceRNA axes. In conclusion, the present study revealed that the RP11‑552F3.9 (RP11‑15A1.7)‑hsa‑miR‑130b‑5p/hsa‑miR‑23a‑5p (hsa‑miR‑302d‑3p)‑LEP interaction axes may be crucial for inducing the adipogenic differentiation of HASCs via involvement in inflammation.

Comparative Secretome Analyses of Primary Murine White and Brown Adipocytes Reveal Novel Adipokines

The adipose organ, including white and brown adipose tissues, is an important player in systemic energy homeostasis, storing excess energy in form of lipids while releasing energy upon various energy demands. Recent studies have demonstrated that white and brown adipocytes also function as endocrine cells and regulate systemic metabolism by secreting factors that act locally and systemically. However, a comparative proteomic analysis of secreted factors from white and brown adipocytes and their responsiveness to adrenergic stimulation has not been reported yet. Therefore, we studied and compared the secretome of white and brown adipocytes, with and without norepinephrine (NE) stimulation. Our results reveal that carbohydrate-metabolism-regulating proteins are preferably secreted from white adipocytes, while brown adipocytes predominantly secrete a large variety of proteins. Upon NE stimulation, an increased secretion of known adipokines is favored by white adipocytes while brown adipocytes secreted higher amounts of novel adipokines. Furthermore, the secretory response between NE-stimulated and basal state was multifaceted addressing lipid and glucose metabolism, adipogenesis, and antioxidative reactions. Intriguingly, NE stimulation drastically changed the secretome in brown adipocytes. In conclusion, our study provides a comprehensive catalogue of novel adipokine candidates secreted from white and brown adipocytes with many of them responsive to NE. Given the beneficial effects of brown adipose tissue activation on its endocrine function and systemic metabolism, this study provides an archive of novel batokine candidates and biomarkers for activated brown adipose tissue.

Identification of genes which regulate stroma-dependent in vitro hematopoiesis

Cultured splenic stroma has been shown to support in vitro hematopoiesis in overlaid bone marrow and spleen progenitors. These co-cultures support longterm production of a novel dendritic-like cell type along with transient production of myeloid cells. They also maintain a progenitor cell population. The splenic stromal lines 5G3 and 3B5 have been identified as a supporter and a non-supporter of hematopoiesis. Based on their gene expression profile, both 5G3 and 3B5 express genes related to hematopoiesis, while 5G3 cells express several unique genes, and show upregulation of some genes over 3B5. Based on gene expression studies, specific inhibitors were tested for capacity to inhibit hematopoiesis in co-cultures. Addition of specific antibodies and small molecule inhibitors identified VCAM1, CXCL12, CSF1 and SPP1 as potential regulators of hematopoiesis, although both are expressed by 5G3 and 3B5. Through inhibition of function, SVEP1 and ALDH1 are also shown here to be deterministic of 5G3 hematopoietic support capacity, since these are uniquely expressed by 5G3 and not 3B5. The achievement of inhibition is notable given the dynamic, longterm nature of co-cultures which involve only small numbers of cells. The alternate plan, to add recombinant soluble factors produced by 5G3 back into 3B5 co-cultures in order to recover in vitro hematopoiesis, proved ineffective. Out of 6 different factors added to 3B5, only IGF2 showed any effect on cell production. The identification of differentially expressed or upregulated genes in 5G3 has provided an insight into potential pathways involved in in vitro hematopoiesis leading to production of dendritic-like cells.

The Role of Placental Hormones in Mediating Maternal Adaptations to Support Pregnancy and Lactation

During pregnancy, the mother must adapt her body systems to support nutrient and oxygen supply for growth of the baby in utero and during the subsequent lactation. These include changes in the cardiovascular, pulmonary, immune and metabolic systems of the mother. Failure to appropriately adjust maternal physiology to the pregnant state may result in pregnancy complications, including gestational diabetes and abnormal birth weight, which can further lead to a range of medically significant complications for the mother and baby. The placenta, which forms the functional interface separating the maternal and fetal circulations, is important for mediating adaptations in maternal physiology. It secretes a plethora of hormones into the maternal circulation which modulate her physiology and transfers the oxygen and nutrients available to the fetus for growth. Among these placental hormones, the prolactin-growth hormone family, steroids and neuropeptides play critical roles in driving maternal physiological adaptations during pregnancy. This review examines the changes that occur in maternal physiology in response to pregnancy and the significance of placental hormone production in mediating such changes.

The role of stem cells in benign tumors

As stem cells contribute to the development and homeostasis of normal adult tissues, malfunction of stem cells in self-renewal and differentiation has been associated with tumorigenesis. A growing number of evidences indicating that tumor initiating cells play a crucial role, not only in malignancies, but also in generation and development of benign tumors. Here we offer an overview of the identification and functional characterization of benign tumor initiating cells in several tissues and organs, which typically show capacities of uncontrolled self-renewal to fuel the tumor growth and abnormal differentiation to give rise to tumor heterogeneity. They may originate from alteration of normal stem cells, which confer the benign tumor initiating cells with different repertoire of "stemness". The plastic functions of benign tumor initiating cells are determined by niche regulation mediated via several signaling and epigenetic cues. Therefore, targeting stem cell function represents an important strategy for understanding the biology and management of benign tumors.

Undernutrition and stage of gestation influence fetal adipose tissue gene expression

Low birthweight is a risk factor for neonatal mortality and adverse metabolic health, both of which are associated with inadequate prenatal adipose tissue development. In the present study, we investigated the impact of maternal undernutrition on the expression of genes that regulate fetal perirenal adipose tissue (PAT) development and function at gestation days 89 and 130 (term=145 days). Singleton fetuses were taken from adolescent ewes that were either fed control (C) intake to maintain adiposity throughout pregnancy or were undernourished (UN) to maintain conception weight but deplete maternal reserves (n=7/group). Fetal weight was independent of maternal intake at day 89, but by day 130, fetuses from UN dams were 17% lighter and had lower PAT mass that contained fewer unilocular adipocytes. Relative PAT expression of IGF1, IGF2, IGF2R and peroxisome proliferator-activated receptor gamma (PPARG) mRNA was lower in UN than in controls, predominantly at day 89. Independent of maternal nutrition, PAT gene expression of PPARG, glycerol-3-phosphate dehydrogenase, hormone sensitive lipase, leptin, uncoupling protein 1 and prolactin receptor increased, whereas IGF1, IGF2, IGF1R and IGF2R decreased between days 89 and 130. Fatty acid synthase and lipoprotein lipase (LPL) mRNAs were not influenced by nutrition or stage of pregnancy. Females had greater LPL and leptin mRNA than males, and LPL, leptin and PPARG mRNAs were decreased in UN at day 89 in females only. PAT gene expression correlations with PAT mass were stronger at day 89 than they were at day 130. These data suggest that the key genes that regulate adipose tissue development and function are active beginning in mid-gestation, at which point they are sensitive to maternal undernutrition: this leads to reduced fetal adiposity by late pregnancy.

Influence of birth weight and gender on lipid status and adipose tissue gene expression in lambs

Intrauterine growth restriction (IUGR) is a risk factor for obesity, particularly when offspring are born into an unrestricted nutritional environment. In this study, we investigated the impact of IUGR and gender on circulating lipids and on expression of adipogenic, lipogenic and adipokine genes in perirenal adipose tissue. Singleton lambs born to overnourished adolescent dams were normal birth weight (N) or IUGR (32% lower birth weight due to placental insufficiency). IUGR lambs exhibited increased fractional growth rates but remained smaller than N lambs at necropsy (d77). At 48 days, fasting plasma triglycerides, non-esterified fatty acids and glycerol were elevated predominantly in IUGR males. Body fat content was independent of prenatal growth but higher in females than in males. In perirenal fat, relative to male lambs, females had larger adipocytes; higher lipoprotein lipase, fatty acid synthase and leptin and lower IGF1, IGF2, IGF1R, IGF2R and hormone-sensitive lipase mRNA expression levels, and all were independent of prenatal growth category; peroxisome proliferator-activated receptor gamma and glycerol-3-phosphate dehydrogenase (G3PDH) mRNA expression were not affected by IUGR or gender. Adiposity indices were inversely related to G3PDH mRNA expression, and for the population as a whole the expression of IGF system genes in perirenal fat was negatively correlated with plasma leptin, fat mass and adipocyte size, and positively correlated with circulating IGF1 levels. Higher plasma lipid levels in IUGR males may predict later adverse metabolic health and obesity, but in early postnatal life gender has the dominant influence on adipose tissue gene expression, reflecting the already established sexual dimorphism in body composition.

Insulin-like growth factor-2 enhances functions of antigen (Ag)-specific regulatory B cells

Regulatory B cells (Bregs) are important in immune regulation. The factors that regulate Breg functions are less clear. Insulin-like growth factor 2 (IGF2) is capable of inducing hematopoietic stem cell differentiation. This study aimed to investigate the role of IGF2 in the development of Bregs and the enhancement of their function. In this study, the expression of IGF1 receptor (IGF1R) and IGF2R in ovalbumin (OVA)-specific B cells (OVAsBCs) was assessed by real time RT-PCR and Western blotting. The release of interleukin (IL)-10 from OVAsBCs and OVAsBC proliferation were assessed by enzyme-linked immunoassay and proliferation assay. The role of IGF2 in enhancing the function of OVAsBCs was tested with an intestinal allergic inflammation mouse model. The results showed that OVAsBCs expressed high levels of IGF2R. Exposure to both IGF2 and a specific antigen (Ag), OVA, markedly enhanced the expression of IL-10 in OVAsBCs as well as enhanced the IL-10(+) OVAsBC proliferation. The concurrent exposure to IGF2 and specific Ag markedly induced the IL-10 promoter DNA demethylation via activating the STAT5 pathway. IGF2 also enhanced both the OVAsBC proliferation in vivo and the effect of Ag-specific immunotherapy on inhibiting allergic inflammation in the intestine. We conclude that OVAsBCs express high levels of IGF2R and that IGF2 increases the expression of IL-10 in OVAsBCs and enhances OVAsBC proliferation and the inhibitory effect on allergic inflammation.

Basic study of soft tissue augmentation by adipose-inductive biomaterial

Reconstructive surgery for tumor resection, trauma, and congenital anomaly involves volume augmentation with autologous tissue transfer. However, a healthy region is damaged as a donor site, and the autologous tissue is transferred like a patchwork to the recipient site. We have attempted to induce adipogenesis activity in artificial biomaterial that is injectable with an injection needle for soft tissue augmentation. First of all, the optimal dose of pioglitazone hydrochloride was examined with adipo-precursor cells in terms of the proliferator-activated receptor-γ mRNA expression levels affected by reagent in vitro. Then, salmon collagen with pioglitazone was adjusted in terms of the dose and the salmon collagen was injected into mouse back using an injection needle in vivo. At 4 weeks after implantation, the pioglitazone collagen gel was substituted by mature adipocytes in comparison with the case for control collagen gel without pioglitazone. These results are indicative of the possibility of promoting adipogenesis using collagen with pioglitazone as an adipose-inductive substance.

Propranolol inhibits growth of hemangioma-initiating cells but does not induce apoptosis

BACKGROUND

Infantile hemangioma (IH) is the most common tumor of infancy. The first-line therapy for IH is propranolol, a nonselective β-adrenergic receptor antagonist. However, mechanisms for the therapeutic effect of propranolol and regrowth of IH following cessation of treatment in some cases are not clear. We have recently shown that IH arises from multipotent stem cells. Whether IH stem cells are responsive to propranolol and are selectively targeted is unknown, and this is the focus of this study.

METHODS

IH stem cells were exposed to propranolol and were assayed for cellular and molecular alterations. We used endothelial cells (ECs) as controls and bone marrow-derived mesenchymal progenitor cells (bm-MPCs) as normal stem/progenitor counterparts to determine selectivity.

RESULTS

Our results show that propranolol significantly reduced IH stem cell growth but failed to induce caspase-3 activation. Normal bm-MPCs and mature ECs showed maintained or increased caspase-3 activation and significantly reduced cyclin-D1 levels. We further show that IH stem cells may escape apoptosis by inducing antiapoptotic pathways.

CONCLUSION

This study reveals that propranolol does not induce apoptosis in IH stem cells, which is in contrast with the result for ECs. Escape from apoptosis in IH stem cells may involve induction of antiapoptotic pathways.

Spontaneous intra-uterine growth restriction modulates the endocrine status and the developmental expression of genes in porcine fetal and neonatal adipose tissue

Low birth weight is correlated with low adiposity at birth, a phenotype that influences neonatal survival and later adiposity. A better understanding of events affecting the fetal adipose tissue development and its functionality around birth is thus needed. This study was undertaken to examine the impact of spontaneous intra-uterine growth restriction (IUGR) on circulating concentrations of hormones and nutrients together with the developmental expression patterns of various genes in subcutaneous adipose tissue of pig fetus during the last third of pregnancy and just after birth. At 71 and 112 days post-conception and 2 days postnatal, pairs of same-sex piglets were chosen within litters to have either a medium (MBW) or a low (LBW) weight (n=6 pairs at each stage). The results indicate that IUGR counteracts the temporal fall of DLK1 gene expression in developing adipose tissue across gestation. It also attenuates the time-dependent increase in expression levels of many genes promoting adipocyte differentiation (PPARG, CEBPA) and lipogenesis (LPL, SREBF1, FASN, FABP4). Opposite responses to IUGR were observed for the IGF system, so that IGF1 mRNA levels were lower (P<0.001) but IGF2 mRNA levels were greater in adipose tissue of LBW piglets compared with MBW piglets. The plasma insulin concentration and the mRNA levels of insulin receptor (INSR) and insulin-responsive glucose transporter (GLUT4) in adipose tissue were also greater in LBW piglets at day 2 postnatal. The data indicate that IUGR delays the normal ontogeny of adipose tissue across gestation and affects the insulin and IGF axes around birth.

Elevated T-box 2 in infantile hemangioma stem cells maintains an adipogenic differentiation-competent state

Infantile hemangioma is a benign vascular tumor that affects 4 to 10% of neonates. A unique feature of hemangiomas is the natural lifecycle, whereby the tumor rapidly grows and then spontaneously regresses to a fibrofatty residuum. We have shown that hemangiomas are derived from mutlipotential stem cells (hemSCs), which differentiate into endothelial cells during the early proliferating phase and into adipocytes during the later involutive phase. T-box 2 (TBX2) is a transcription factor involved in controlling cell-fate decisions, and is highly expressed during the proliferating phase of hemangioma development. We hypothesize that TBX2 expression would be high in hemSCs derived from human hemangiomas and inhibiting TBX2 would result in changes in hemSC differentiation potential. To test our hypothesis, we analyzed hemSCs for TBX2 mRNA and protein expression. We then used RNA interference and TBX2 overexpression to determine the effect of altering TBX2 levels on hemSC growth and differentiation. Our studies show that TBX2 is highly expressed in hemSCs compared with a panel of normal stem/progenitor cells and mature vascular cells. TBX2 knockdown completely abolished adipogenic differentiation of hemSCs without significantly altering growth. Furthermore, overexpression of TBX2 led to enhanced adipogenic differentiation ability possibly through induction of C/EBPβ. From these findings, we believe that TBX2 is active in hemSCs and that TBX2 maintains adipogenic differentiation-competent state of hemSCs. These findings may be important in the development of better treatment options for hemangiomas to accelerate involution.

Knockdown of ZBED6 is not associated with changes in murine preadipocyte proliferation or differentiation

ZBED6 was identified as a transcription factor that affects muscle mass and fat deposition in pigs. Mechanisms mediating effects on fat mass are unclear. The objective was to determine the effect of ZBED6 mRNA knockdown on 3T3-L1 preadipocyte differentiation and gene expression. Differentiation was associated with increased mRNA abundance of CEBP/α (P < 0.05), CEBP/β (P < 0.05), CEBP/δ (P < 0.05), FASN (P < 0.05), PPARγ (P < 0.05), and SREBP-1 (P < 0.05), and decreased abundance of PREF-1 (P < 0.05). Knockdown of ZBED6 was not associated with changes in mRNA abundance of selected genes, lipid accumulation, lipid droplet size, or cell number. These results suggest that ZBED6 does not play a major role in preadipocyte differentiation.