Early Adipose Research Articles

Early adipose tissue wasting in a novel preclinical model of human lung cancer cachexia.

Cancer cachexia (CC), a syndrome of skeletal muscle and adipose tissue wasting, reduces responsiveness to therapies and increases mortality. There are no approved treatments for CC, which may relate to discordance between pre-clinical models and human CC. To address the need for clinically relevant models, we generated tamoxifen-inducible, epithelial cell specific Kras G12D/+ ( G12D ) mice. G12D mice develop CC over a protracted time course and phenocopy tissue, cellular, mutational, transcriptomic, and metabolic characteristics of human lung CC. CC in G12D mice is characterized by early loss of adipose tissue, a phenotype confirmed in a large cohort of patients with lung cancer. Tumor-released factors promote adipocyte lipolysis, a driver of adipose wasting in human CC, and adipose tissue wasting was inversely related to tumor burden. Thus, G12D mice model key features of human lung CC and suggest a novel role for early adipose tissue wasting in CC.

A novel preclinical model of human lung cancer cachexia

Most patients with lung cancer are afflicted with cancer cachexia (CC), a syndrome characterized by wasting of muscle and fat tissues, which leads to poor treatment response and increased mortality. Pre-clinical models used to study CC often do not mimic the human condition, which may explain why there are no approved treatments for CC. To overcome this barrier, we sought to develop a model of lung CC that better recapitulates the pathoetiological characteristics of human lung CC using mice with a tamoxifen-inducible, lung epithelial cell (club cell)-specific KrasG12D allele ( G12D mice). We hypothesized that this model would mimic human CC in tumor location and burden, rate of progression, and tumor-driven tissue wasting. Following induction by tamoxifen injection, adenocarcinomas developed in the terminal bronchioles as early as 3.5 weeks post-induction and were accompanied by loss of 15% of animal body weight over a 12-week period. This weight loss began at 6 weeks and yielded a slow rate of CC progression (-1.9%/week) relative to currently available lung CC models (-5-10%/week). Body weight loss resulted from reductions in hindlimb muscle mass (18-30%) and profound depletion of inguinal and gonadal adipose tissue depots (60-70%) compared to age-matched wild-type (WT) littermates. At 6 weeks post-induction, fat tissue was reduced at the tissue and cellular levels while reductions in hindlimb muscle weight and fiber size were not observed. This fat loss corresponded with increased serum glycerol levels at 6 and 12 weeks, a metabolic characteristic that was also found in patients with lung cancer receiving treatment. Lung organoids were developed from G12D and WT mice. G12D organoids exhibited similarities in gene expression to human lung tumors ( RNAseq) and their conditioned medium (CM) elicited glycerol release from cultured 3T3L1 adipocytes compared to CM from WT organoids, suggesting that tumor-derived factors may contribute to early adipose tissue atrophy. Collectively, these findings suggest that G12D mice may be a valuable model, well-suited to identify mechanisms leading to CC and test preventative therapies. NIH R01 AR065826(MJT), NCI R21 CA283492(MJT), T32- HL076122-18(DBS/MEP), R01 CA273238 (YJ-H) and the University of Vermont Cancer Center. Funding support for RNAseq provided by Zymo Impact Initiative Grant (DBS). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A synonymous single nucleotide polymorphism (g.36417726C > A) in the Lama2 gene influencing fat deposition is associated with post-partum anestrus interval in Murrah buffalo

Postpartum absence of estrus exhibition known as postpartum anestrus interval (PPAI) for more than 90 days after calving is a concerning issue for dairy buffalo farmers' economy. The PPAI duration is influenced by both management practices and animal genetics. Investigating genetic markers associated with PPAI is crucial for incorporating them into marker-assisted selection programs. Towards this goal, our study focused on exploring potential genetic markers from early postpartum adipose tissue gene networks. We successfully identified 24 Single Nucleotide Polymorphisms (SNPs) within 9 candidate genes. In our initial analysis involving 100 buffaloes, we detected a significant association (P = 0.02267) between a specific synonymous SNP within the Lama2 gene (g.36417726C > A) and PPAI. This finding was subsequently validated (P = 0.02937) in a larger cohort of 415 buffaloes, where the SNP explained 1.36 % of the genetic variance. Intriguingly, buffaloes with the CC genotype of this SNP exhibited a PPAI that was 12.71 ± 3.21 days longer compared to buffaloes with AA and CA genotypes. To gain insight into the functional relevance of this SNP, a computational analysis was performed which indicated that the C allele of the SNP (g.36417726C > A) increased the stability of LAMA2 mRNA compared to the A allele. This computational prediction was corroborated by observing a significant increase (P = 0.01798) in Lama2 gene expression (greater than 8-fold) and higher fat percentage (P < 0.05) in adipose tissue of CC genotypes (48.78 ± 1.87 %) compared to AA genotypes (33.59 ± 4.5 %). Furthermore, we noted a significant (P < 0.05) upregulation of C/ebpβ, Pparγ, Fasn, C/ebpα, and Pnpla2 genes, along with the downregulation of Bmp2 and Ptch1 in CC genotypes as opposed to AA genotypes. This observation suggests the involvement of the Pparγ-mediated pathway in both adipogenesis and lipolysis within CC genotypes. In summary, our comprehensive analysis involving association and functional validation underscores the potential of the SNP (g.36417726C > A) within the Lama2 gene as a promising genetic marker against extended PPAI in Murrah buffalo.

Combining decellularized adipose tissue with decellularized adventitia extravascular matrix or small intestinal submucosa matrix for the construction of vascularized tissue-engineered adipose

Adipose tissue is an endocrine organ. It serves many important functions, such as energy storage, hormones secretion, and providing insulation, cushioning and aesthetics to the body etc. Adipose tissue engineering offers a promising treatment for soft tissue defects. Early adipose tissue production and long-term survival are closely associated with angiogenesis. Decellularized matrix has a natural ECM (extracellular matrix) component, good biocompatibility, and low immunogenicity. Therefore, in this study, the injectable composite hydrogels were developed to construct vascularized tissue-engineered adipose by using the pro-angiogenic effects of aortic adventitia extravascular matrix (Adv) or small intestinal submucosa (SIS), and the pro-adipogenic effects of decellularized adipose tissue (DAT). The composite hydrogels were cross-linked by genipin. The adipogenic and angiogenic abilities of composite hydrogels were investigated in vitro, and in a rat dorsal subcutaneous implant model. The results showed that DAT and SIS or Adv 1:1 composite hydrogel promoted the migration and tube formation of endothelial cells. Furthermore, DAT and SIS or Adv 1:1 composite hydrogel enhanced adipogenic differentiation of adipose-derived mesenchymal stem cells (ASCs) through activation of PPARγ and C/EBPα. The in vivo studies further demonstrated that DAT with SIS or Adv in a 1:1 ratio also significantly promoted adipogenesis and angiogenesis. In addition, DAT with SIS or Adv in a 1:1 ratio hydrogel recruited macrophage population with enhanced M2-type macrophage polarization, suggesting a positive effect of inflammatory response on angiogenesis. In conclusion, these data suggest that the composite hydrogels of DAT with SIS or Adv in 1:1 ratio have apparent pro-adiogenic and angiogenic abilities, thus providing a promising cell-free tissue engineering biomaterial with broad clinical applications. Statement of significanceDecellularized adipose tissue (DAT) has emerged as an important biomaterial in adipose tissue regeneration. Early adipose tissue production and long-term survival is tightly related to the angiogenesis. The revascularization of the DAT is a key issue that needs to be solved in adipose regeneration. In this study, the injectable composite hydrogels were developed by using DAT with Adv (aortic adventitia extravascular matrix) or SIS (small intestinal submucosa) in different ratio. We demonstrated that the combination of DAT with SIS or Adv in 1:1 ratio effectively improved the proliferation of adipose stem cells and endothelial cells, and promoted greater adipose regeneration and tissue vascularization as compared to the DAT scaffold. This study provides the potential biomaterial for clinical soft tissue regeneration.

P13-038-23 Early Adipose Tissue Wasting in a Novel Model of Lung Cancer Cachexia

P13-038-23 Early Adipose Tissue Wasting in a Novel Model of Lung Cancer Cachexia

1666-P: ScRNAseq–Based Analysis of the Stromal Immune Cell Composition in Murine Preweaning and Adult White Adipose Tissues

Early postnatal adipose growth is essential to establish a functional metabolism. Conversely, proportional adipose expansion in adults results in insulin resistance. Despite adipocytes, immune cells play a pivotal role in orchestrating adipose tissue function and expansion. To this end, we performed an in-depth analysis of scRNAseq data of immune cell populations of 2 weeks (pre-weaning) and 8 weeks old (adult) murine subcutaneous and perigonadal adipose depots. Our analysis revealed 15 distinct immune cell clusters. Most immune cell types were found in all depots and ages. Among the detected T-cell populations, we only observed differences in the abundance of naïve T cells, which were predominantly found in in subcutaneous white adipose tissue, irrespective of age. Similar to human, we could define several murine macrophage subtypes. Among them, perivascular macrophages (PVM) were predominantly found in subcutaneous white adipose tissue of 2 weeks old mice. RNA-velocity analysis and pseudotime trajectory construction suggested a developmental trajectory from lipid-associated macrophages (LAM) to PVM, which was further corroborated by analysis of gene expression dynamics resolved along latent time of white adipose tissue macrophages from 2 weeks old mice. Further analysis revealed that the top-ranked 100 genes of LAM were associated with the regulation of endothelial cell migration and proliferation (Nrp1, Grn, Glul, Sash1, Ccl24), blood vessel morphogenesis (Nrp1, Tgfbr2) and the regulation of epithelial cell proliferation. In summary, we provide a comprehensive overview of the immune cell composition of pre-weaning and adults murine adipose tissues. Moreover, we provide in-depth analysis of T-cell and macrophage populations and their relationship and dependency based on mRNA expression analysis. Disclosure X. Yan: None. V. Miok: None. R. Karlina: None. A. Böttcher: None. D. Lutter: None. H. Lickert: Research Support; Eli Lilly and Company. C. Garcia Caceres: None. S. Ussar: Research Support; Novo Nordisk. Funding China Scholarship Council (201908370218)

ODP005 Molecular Characterization of Early Adipose Tissue Remodeling and Fibrosis in a Murine Model of Diet-Induced Obesity.

Abstract One of the many pathophysiological changes associated with obesity is the build up of structural and physiochemical extracellular matrix components in adipose depots, known as adipose tissue fibrosis. Like liver fibrosis, adipose tissue fibrosis occurs as a response to chronic injury and inflammation and can perpetuate inflammation and impede proper tissue functioning. Key adipose tissue fibrosis markers have been identified in obese adipose tissue, including collagen VI and its cleavage product endotrophin, however, adipose tissue fibrosis remains poorly characterized, particularly in its initiating phases. We have developed and characterized a murine model of diet-induced obesity (12 weeks of high fat feeding), insulin resistance, and early fibrotic development in both sexes. While diagnosable fibrosis was absent, as determined by picrosirius red staining, we detected elevated collagen VI, TGF-β, TNF-α, and TIMP-1 mRNA in gonadal white adipose of both sexes. TIMP-4 was decreased in males but elevated in females. Immunohistochemical analysis revealed pericellular build up of collagen VI immunoreactivity in males only, co-localized with immunoreactivity of its protease MMP-14, which is known to generate the pro-fibrotic fragment endotrophin. This work identifies key sex differences and fibrosis markers present during the initiation of adipose tissue fibrosis, earlier than diagnosable fibrosis can be detected, highlighting their potential as therapeutic targets for prevention or reversal of fibrosis in the treatment of obesity and insulin resistance. Presentation: No date and time listed

Slower Growth during Lactation Rescues Early Cardiovascular and Adipose Tissue Hypertrophy Induced by Fetal Undernutrition in Rats.

Low birth weight (LBW) and accelerated growth during lactation are associated with cardiometabolic disease development. LBW offspring from rats exposed to undernutrition during gestation (MUN) develops hypertension. In this rat model, we tested if slower postnatal growth improves early cardiometabolic alterations. MUN dams were fed ad libitum during gestation days 1–10, with 50% of the daily intake during days 11–21 and ad libitum during lactation. Control dams were always fed ad libitum. Pups were maintained with their own mother or cross-fostered. Body weight and length were recorded weekly, and breastmilk was obtained. At weaning, the heart was evaluated by echocardiography, and aorta structure and adipocytes in white perivascular fat were studied by confocal microscopy (size, % beige-adipocytes by Mitotracker staining). Breastmilk protein and fat content were not significantly different between groups. Compared to controls, MUN males significantly accelerated body weight gain during the exclusive lactation period (days 1–14) while females accelerated during the last week; length growth was slower in MUN rats from both sexes. By weaning, MUN males, but not females, showed reduced diastolic function and hypertrophy in the heart, aorta, and adipocytes; the percentage of beige-type adipocytes was smaller in MUN males and females. Fostering MUN offspring on control dams significantly reduced weight gain rate, cardiovascular, and fat hypertrophy, increasing beige-adipocyte proportion. Control offspring nursed by MUN mothers reduced body growth gain, without cardiovascular modifications. In conclusion, slower growth during lactation can rescue early cardiovascular alterations induced by fetal undernutrition. Exclusive lactation was a key period, despite no modifications in breastmilk macronutrients, suggesting the role of bioactive components. Our data support that lactation is a key period to counteract cardiometabolic disease programming in LBW and a potential intervention window for the mother.

208 Single Cell RNA Sequencing (Scrna-seq) in Studying the Early Embryonic Muscle Development

Abstract During the early development, skeletal muscle, adipose, and connective tissues have high plasticity and are sensitive to in uterine nutritional fluctuations. During the past decade, maternal nutrition-induced changes in myogenesis and adipogenesis during the fetal stage have been extensively studied and their alterations are closely associated with changes in production efficiency and meat quality of farm animals. Organogenesis initiates during the embryonic stage, which sets the blueprint for later growth and development. Limited but growing evidence support that nutritional changes during the early embryonic stage also have profound effects on animal production efficiency. Using single-cell transcriptomic analysis (scRNA-seq), we investigated the effects of maternal obesity (MO) on the embryonic myogenesis in embryonic day 9.5 (E9.5) mouse embryos. First, we identified myogenic subpopulations within the dermomyotome (DM) and a developmental trajectory of embryonic myogenesis was reconstructed. Our results showed that MO induced systematic hypoxia, which was correlated with enhanced BMP signaling and impaired skeletal muscle differentiation within the DM. The Notch-signaling effectors, HES1 and HEY1, which act downstream of BMP signaling, were activated by hypoxia-inducible factor 1 (HIF1A) and suppressed myogenic differentiation through transcriptionally repressing an important myogenic regulator MEF2C. In conclusion, MO induces hypoxia and impairs myogenic differentiation by up-regulating BMP signaling within the DM, which may account for the disruptions of skeletal muscle development and function in progeny. Understanding the developmental programming of the skeletal muscle, as well as adipose and fibrotic tissues, especially at the embryonic stage, will facilitate the development of stage-specific nutritional management strategies to optimize production efficiency and meat quality.

Low n-6/n-3 Gestation and Lactation Diets Influence Early Performance, Muscle and Adipose Polyunsaturated Fatty Acid Content and Deposition, and Relative Abundance of Proteins in Suckling Piglets.

Elevated omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) ratios in swine diets can potentially impose a higher risk of inflammatory and metabolic diseases in swine. A low ratio between the two omega PUFAs has beneficial effects on sows’ and piglets’ production performance and immunity status. At present, there are few studies on how sow nutrition directly affects the protein and fat deposition in suckling piglets. Two groups of sows were fed diets with high or low n-6/n-3 polyunsaturated ratios of 13:1 (SOY) and 4:1 (LIN), respectively, during gestation and lactation. Longissimus dorsi muscle and adipose tissue from newborn piglets, nourished only with sow’s milk, were subjected to fatty acid profiling by gas chromatography–mass spectrometry (GC-MS) and to proteomics assays based on nano-liquid chromatography coupled to high-resolution tandem mass spectrometry (nLC-HRMS). Fatty acid profiles on both muscle and adipose tissues resembled the magnitude of the differences between fatty acid across diets. Proteomic analysis revealed overabundance of 4 muscle and 11 adipose tissue proteins in SOY compared to LIN in both piglet tissues. The detected overabundance of haptoglobin, an acute-phase protein, and the stimulation of protein-coding genes and proteins related to the innate immune response and acute inflammatory response could be associated with the pro-inflammatory role of n-6 PUFAs.

Polybrominated diphenyl ether congener 99 (PBDE 99) promotes adipocyte lineage commitment of C3H10T1/2 mesenchymal stem cells

Obesogens are defined as chemicals that trigger obesity partially by stimulating adipogenesis. Adipogenesis consists of two successive processes: the adipocyte lineage commitment of pluripotent stem cells and the differentiation of preadipocytes. Compared with the differentiation of preadipocytes, the effects of most environmental obesogens on adipocyte lineage commitment remain largely unknown. In this study, investigations are performed to explore the influences of PBDE 99 on the adipocyte lineage commitment based on C3H10T1/2, which has been widely used as a mesenchymal stem cell (MSC) model. Our results indicated that exposure to PBDE 99 during commitment stage resulted in significant up-regulation of subsequent adipogenesis in C3H10T1/2 MSCs. Interestingly, PBDE 99 did not affect the osteogenesis of C3H10T1/2 MSCs, although the adipogenesis and osteogenesis of MSCs are typically reciprocal. PBDE 99 was further demonstrated to significantly decrease the expression of Pref1, the marker of very early adipose mesenchymal precursor, and its downstream effector, Sox9. This result strongly suggested that PBDE 99 facilitated adipocyte commitment to exert adipogenic effect on C3H10T1/2 MSCs. Mechanistic studies revealed that PBDE 99 efficiently inhibited Hedgehog signaling transduction, a conserved negative regulator of the adipocyte lineage commitment. Furthermore, the effects of PBDE 99 on adipogenesis were abrogated by the co-treatment with SAG, a specific Hedgehog signaling activator, suggesting inhibition of Hedgehog signaling is responsible for the effect of PBDE 99 on adipocyte commitment. Taking together, these results strongly suggested enhanced adipocyte lineage commitment was involved in potential obesogenic effect of PBDE 99, presumably through repressing Hedgehog signalling during commitment stage. Moreover, the results of this study indicated that C3H10T1/2 can be used as a feasible MSCs cell model to evaluate the capabilities of potential obesogens on adipocyte commitment.

Neonatal exposure to a wild-derived microbiome protects mice against diet-induced obesity.

Obesity and its consequences are among the greatest challenges in healthcare. The gut microbiome is recognized as a key factor in the pathogenesis of obesity. Using a mouse model, we show here that a wild-derived microbiome protects against excessive weight gain, severe fatty liver disease and metabolic syndrome during a 10-week course of high-fat diet. This phenotype is transferable only during the first weeks of life. In adult mice, neither transfer nor severe disturbance of the wild-type microbiome modifies the metabolic response to a high-fat diet. The protective phenotype is associated with increased secretion of metabolic hormones and increased energy expenditure through activation of brown adipose tissue. Thus, we identify a microbiome that protects against weight gain and its negative consequences through metabolic programming in early life. Translation of these results to humans may identify early-life therapeutics that protect against obesity.

Greater Maternal Dietary Fiber Intake Protects Against Infant Central Fat Accretion Related to High Maternal Fructose Intake

ObjectivesGreater maternal fructose intake is linked to greater offspring fat accrual, while dietary fiber intake is related to lower weight gain and a more favorable adipose tissue distribution. However, data are lacking investigating these relationships in the especially critical time of pregnancy and early infancy. We explored the relationships between maternal fructose and fiber intake on early offspring adipose tissue accrual. MethodsThis is a secondary analysis using data from a prenatal DHA supplementation trial (ADORE HD083292). At enrollment (12–16 wks), women completed the DHQ II food frequency questionnaire. ADORE mothers were invited to enroll in the GAINS infant follow up study (DK118220). Infant skinfolds were assessed two weeks and six months at three central sites (suprailiac, subscapular, flank) and three peripheral sites (biceps, triceps, thigh). Median splits were calculated for maternal fructose and total dietary fiber intake (< 50th percentile, ≥50th percentile). An ANCOVA assessed the main effects of maternal fructose and fiber intake on infant fat accrual (central and peripheral). ResultsData were available on n = 61 infants. For the change in infant central FM, a significant interaction (p = 0.034) was found between maternal fructose intake and dietary fiber intake. No effect of fiber was found in offspring exposed to low fructose intake. However, in offspring exposed to high fructose intake during pregnancy, exposure to high maternal dietary fiber intake was related to lower central FM accrual (high fiber intake: 4.2 mm vs. low fiber intake 6.9 mm; p = 0.016). No significant main effects or interaction was detected for the change in peripheral FM. ConclusionsIn offspring exposed to greater maternal fructose consumption during pregnancy, greater maternal intake of dietary fiber was related to lower early offspring central fat accretion. Interventions targeting to decrease maternal fructose consumption and increase maternal dietary fiber intake may positively impact offspring fat accretion. Funding SourcesNIH Awards R01 HD083292 and R01 DK118220.

Evaluation of Maternal Dietary n-3 LCPUFA Supplementation as a Primary Strategy to Reduce Offspring Obesity: Lessons From the INFAT Trial and Implications for Future Research.

Preclinical research suggests that early exposure to LCPUFAs is associated with offspring health outcomes, although evidence in humans is rather unclear. In 2006, we established the Impact of Nutritional Fatty acids during pregnancy and lactation on early human Adipose Tissue development (INFAT) study, a prospective randomized controlled intervention trial that examined whether decreasing the n-6/n-3 LCPUFA ratio during pregnancy and lactation influences offspring adipose tissue development in children up to 5 years. Our results indicate that maternal supplementation with n-3 LCPUFAs does not reduce offspring obesity risk, which is in line with recent publications. This perspective describes the challenges and lessons learned from our clinical trial. We discuss key findings and critically evaluate differences in study design, methodology, and analyses across similar intervention trials that may partly explain heterogeneous results. Summarizing evidence from human trials, we conclude that n-3 LCPUFA supplementation should not be recommended as a primordial strategy to prevent childhood obesity. Instead, it remains unknown whether n-3 LCPUFA supplementation could benefit high-risk subgroups and some vulnerable maternal/child populations. The perspectives offered herein are derived largely from insights gained from ours and similar n-3 LCPUFA intervention trials and help to provide direction for future research that examines the impact of maternal nutritional exposure on offspring health and disease outcomes.

In Human and Mouse Spino-Cerebellar Tissue, Ataxin-2 Expansion Affects Ceramide-Sphingomyelin Metabolism.

Ataxin-2 (human gene symbol ATXN2) acts during stress responses, modulating mRNA translation and nutrient metabolism. Ataxin-2 knockout mice exhibit progressive obesity, dyslipidemia, and insulin resistance. Conversely, the progressive ATXN2 gain of function due to the fact of polyglutamine (polyQ) expansions leads to a dominantly inherited neurodegenerative process named spinocerebellar ataxia type 2 (SCA2) with early adipose tissue loss and late muscle atrophy. We tried to understand lipid dysregulation in a SCA2 patient brain and in an authentic mouse model. Thin layer chromatography of a patient cerebellum was compared to the lipid metabolome of Atxn2-CAG100-Knockin (KIN) mouse spinocerebellar tissue. The human pathology caused deficits of sulfatide, galactosylceramide, cholesterol, C22/24-sphingomyelin, and gangliosides GM1a/GD1b despite quite normal levels of C18-sphingomyelin. Cerebellum and spinal cord from the KIN mouse showed a consistent decrease of various ceramides with a significant elevation of sphingosine in the more severely affected spinal cord. Deficiency of C24/26-sphingomyelins contrasted with excess C18/20-sphingomyelin. Spinocerebellar expression profiling revealed consistent reductions of CERS protein isoforms, Sptlc2 and Smpd3, but upregulation of Cers2 mRNA, as prominent anomalies in the ceramide–sphingosine metabolism. Reduction of Asah2 mRNA correlated to deficient S1P levels. In addition, downregulations for the elongase Elovl1, Elovl4, Elovl5 mRNAs and ELOVL4 protein explain the deficit of very long-chain sphingomyelin. Reduced ASMase protein levels correlated to the accumulation of long-chain sphingomyelin. Overall, a deficit of myelin lipids was prominent in SCA2 nervous tissue at prefinal stage and not compensated by transcriptional adaptation of several metabolic enzymes. Myelination is controlled by mTORC1 signals; thus, our human and murine observations are in agreement with the known role of ATXN2 yeast, nematode, and mouse orthologs as mTORC1 inhibitors and autophagy promoters.

Epigenetic alteration of Rho guanine nucleotide exchange Factor 11 (ARHGEF11) in cord blood samples in macrosomia exposed to intrauterine hyperglycemia

Background: Macrosomia at birth is associated with maternal hyperglycemia and leads to subsequent susceptibility to obesity, abnormal glucose metabolism, hypertension, and dyslipidemia in offspring. Epigenetic reprogramming has been reported to be involved in the development of human diseases caused by suboptimal environmental or nutritional factors. The study was aiming to explore epigenetic mechanism influences on macrosomic infants exposed to intrauterine hyperglycemia. We performed a genome-wide analysis of DNA methylation in cord blood from macrosomic infants born to women with gestational diabetes in order to identify genes related to fetal growth or early adipose tissue development.Methods: To analyze the epigenetic patterns in umbilical cord blood in gestational diabetes mellitus (GDM), we collected umbilical cord blood from women with GDM (mean pregestational BMI of 24.4 kg/m2 and mean neonatal birth weight of 4366 g) and normal glucose-tolerant women (mean pregestational BMI of 19.8 kg/m2 and mean neonatal birth weight of 3166 g). Differentially methylated genes in the GDM group were identified using the Infinium HumanMethylation450 BeadChip array.Results: A total of 1251 genes were differentially methylated compared to the controls (p < .01). The methylation microarray data showed that two specific CpG sites (cg12604331 and cg08480098) in the gene body of ARHGEF11 were significantly hypomethylated in the cord blood in macrosomic infants. Altered DNA methylation levels of ARHGEF11 were negatively correlated with glucose levels and neonatal birth weight.Conclusions: Exposure to adverse intrauterine environments can alter fetal development, such as by affecting the nutritional status of the fetus. Such exposure can also result in significant epigenetic modifications, including DNA methylation, which could serve as a potential marker for nutrition and metabolic conditions at the neonatal stage or even in the adult.

Sox9-Meis1 Inactivation Is Required for Adipogenesis, Advancing Pref-1+ to PDGFRα+ Cells

SUMMARYAdipocytes arise from the commitment and differentiation of adipose precursors in white adipose tissue (WAT). In studying adipogenesis, precursor markers, including Pref-1 and PDGFRα, are used to isolate precursors from stromal vascular fractions of WAT, but the relation among the markers is not known. Here, we used the Pref-1 promoter-rtTA system in mice for labeling Pref-1+ cells and for inducible inactivation of the Pref-1 target Sox9. We show the requirement of Sox9 for the maintenance of Pref-1+ proliferative, early precursors. Upon Sox9 inactivation, these Pref-1+ cells become PDGFRα+ cells that express early adipogenic markers. Thus, we show that Pref-1+ cells precede PDGFRα+ cells in the adipogenic pathway and that Sox9 inactivation is required for WAT growth and expansion. Furthermore, we show that in maintaining early adipose precursors, Sox9 activates Meis1, which prevents adipogenic differentiation. Our study also demonstrates the Pref-1 promoter-rtTA system for inducible gene inactivation in early adipose precursor populations.

Adipocyte C1QTNF5 expression is BMI-dependently related to early adipose tissue dysfunction and systemic CTRP5 serum levels in obese children.

The recently identified adipocytokine C1QTNF5 (encodes for CTRP5) has been demonstrated to inhibit pro-metabolic insulin signaling in adipocytes. We hypothesized that adipocyte C1QTNF5 expression in subcutaneous (sc) adipose tissue (AT) would correlate with the degree of obesity, systemic CTRP5 serum levels, and early AT and metabolic dysfunction in children. Sc AT samples were obtained from 33 healthy Caucasian lean children aged 10.06±4.84 years and 42 overweight and obese children aged 13.34±3.12 years. C1QTNF5 expression in sc AT as well as in investigated cell lines was assessed by quantitative real-time PCR. Systemic CTRP5 levels were assessed by ELISA. C1QTNF5 expression in sc adipocytes increased with body mass index (BMI) standard deviation score (SDS; R=0.48, P<0.001), body fat percentage (R=0.4, P=0.004), adipocyte number (R=0.69, P<0.001) and systemic CTRP5 serum levels (R=0.28, P=0.025) whereas expression in the stromal vascular fraction (SVF) was inversely correlated with BMI SDS (R=-0.24, P=0.04). Multiple regression analysis confirmed that BMI SDS was the strongest independent predictor for C1QTNF5 expression in sc adipocytes. SVF C1QTNF5 levels strongly correlated with SVF CD31 expression (R=0.54, P<0.001) indicating expression by endothelial cells. Primary human endothelial cells demonstrated stronger expression compared with human Simpson-Golahbi-Behmel syndrome pre-adipocytes and adipocytes. Adipocyte C1QTNF5 expression levels were BMI-dependently related to fasting insulin (R=0.3, P=0.03) and leptin serum levels (R=0.5, P<0.001). Sc AT samples containing crown-like structures (CLS) demonstrated increased adipocyte C1QTNF5 expression compared to CLS-negative samples (P=0.03). Functionally, tumor necrosis factor (TNF)α caused a fourfold induction of C1QTNF5 in human adipocytes (P<0.001) and a 50% reduction in primary human endothelial cells (P<0.001). In children adipocyte C1QTNF5 expression is already strongly related to the degree of obesity and is associated with obesity-related AT alterations, systemic CTRP5 serum levels as well as circulating markers of metabolic disease and is positively regulated by TNFα in vitro.

Short-term high-fat diet compromises myocardial function: a radial strain rate imaging study.

Long-term high-fat diet (HFD) induces both cardiac remodelling and myocardial dysfunction in murine models. The aim was to assess the time course and mechanisms of metabolic and cardiac modifications induced by short-term HFD in wild-type (WT) mice. Thirty-three WT mice were subjected to HFD (60% fat, n = 16) and chow diet (CD, 13% fat, n = 17). Metabolic and echocardiographic data were collected at baseline and every 5 weeks for 20 weeks. Invasive haemodynamic data and myocardial samples were collected at 5 and 20 weeks. Echocardiographic data included left ventricular (LV) diameters and thickness, and systolic function using radial strain rate (SR). Histological assessment of cardiomyocyte and adipocyte sizes, interstitial fibrosis, and apoptosis index were performed. During follow-up, body weight, and glycaemia levels were higher in HFD than in CD mice, in association with an early adipose tissue remodelling. Despite no difference between both groups in blood pressure and LV mass at 5 weeks, an early LV dysfunction was observed in HFD mice as assessed by radial SR (21 ± 0.8 vs. 27 ± 0.8 unit/s, P < 0.001) and haemodynamic assessment. During follow-up, both groups demonstrated a progressive systolic and diastolic LV dysfunction and remodelling including dilatation and hypertrophy, which were more severe in HFD mice. Compared with CD mice, the early LV impairment in HFD mice was coupled with a higher cardiomyocyte apoptosis level (0.95 vs. 0.02%, P < 0.05) associated with an interstitial fibrosis process (2.3 vs. 0.2%, P < 0.05), which worsen during follow-up. The HFD promoted early metabolic and cardiac dysfunctions, and adipose and myocardial tissues remodelling.

Early infant adipose deposition is positively associated with the n-6 to n-3 fatty acid ratio in human milk independent of maternal BMI.

Background/ObjectivesExcessive infant weight gain in the first 6-months of life is a powerful predictor of childhood obesity and related health risks. In mice, omega-6 fatty acids (FA) serve as potent ligands driving adipogenesis during early development. The ratio of omega-6 relative to omega-3 (n-6/n-3) FA in human milk (HM) has increased 3-fold over the last 30 years, but the impact of this shift on infant adipose development remains undetermined. This study investigated how maternal obesity and maternal dietary FA (as reflected in maternal red blood cells (RBC) composition) influenced HM n-6 and n-3 FAs, and whether the HM n-6/n-3 ratio was associated with changes in infant adipose deposition between 2-weeks and 4-months postpartum.Subjects/MethodsForty-eight infants from normal-weight (NW), overweight (OW) and obese (OB) mothers were exclusively or predominantly breastfed over the first 4 months of lactation. Mid-feed HM and maternal RBC were collected at either transitional (2-weeks) or established (4-months) lactation, along with infant body composition assessed using air-displacement plethysmography. The FA composition of HM and maternal RBC was measured quantitatively by lipid mass spectrometry.ResultsIn transitional and established HM, DHA was lower (P=0.008; 0.005) and the AA/DHA+EPA ratio was higher (P=0.05; 0.02) in the OB relative to the NW group. Maternal prepregnancy BMI and AA/ DHA+EPA ratios in transitional and established HM were moderately correlated (P=0.018; 0.001). Total infant fat mass was increased in the upper AA/DHA+EPA tertile of established HM relative to the lower tertile (P=0.019). The amount of changes in infant fat mass and % body fat were predicted by AA/EPA+DHA ratios in established HM (P=0.038; 0.010).ConclusionsPerinatal infant exposures to a high AA/EPA+DHA ratio during the first 4-months of life, which is primarily reflective of maternal dietary FA, may significantly contribute to the way infants accumulate adipose.