We recently identified endotrophin as an adipokine with potent tumour-promoting effects. However, the direct effects of local accumulation of endotrophin in adipose tissue have not yet been studied. Here we use a doxycycline-inducible adipocyte-specific endotrophin overexpression model to demonstrate that endotrophin plays a pivotal role in shaping a metabolically unfavourable microenvironment in adipose tissue during consumption of a high-fat diet (HFD). Endotrophin serves as a powerful co-stimulator of pathologically relevant pathways within the ‘unhealthy’ adipose tissue milieu, triggering fibrosis and inflammation and ultimately leading to enhanced insulin resistance. We further demonstrate that blocking endotrophin with a neutralizing antibody ameliorates metabolically adverse effects and effectively reverses metabolic dysfunction induced during HFD exposure. Collectively, our findings demonstrate that endotrophin exerts a major influence in adipose tissue, eventually resulting in systemic elevation of pro-inflammatory cytokines and insulin resistance, and the results establish endotrophin as a potential target in the context of metabolism and cancer.

“Beige” adipocytes reside in white adipose tissue (WAT) and dissipate energy as heat. Several studies have shown that cold temperature can activate proopiomelanocortin-expressing (POMC) neurons and increase sympathetic neuronal tone to regulate WAT beiging. However, WAT is traditionally known to be sparsely innervated. Details regarding the neuronal innervation and more importantly, the propagation of the signal within the population of “beige” adipocytes are sparse. Here, we demonstrate that beige adipocytes display an increased cell-to-cell coupling via connexin 43 (Cx43) gap junction channels. Blocking of Cx43 channels by 18α-glycyrrhetinic acid decreases POMC activation-induced adipose tissue beiging. Adipocyte-specific deletion of Cx43 reduces WAT beiging to a level similar to that observed in denervated fat pads. In contrast, overexpression of Cx43 is sufficient to promote beiging even with mild cold stimuli. These data reveal the importance of cell-to-cell communication in adipose tissue for the propagation of limited neuronal inputs, resulting in effective beiging.

Obesity promotes insulin resistance associated with liver inflammation, elevated glucose production, and type 2 diabetes. Although insulin resistance is attenuated in genetic mouse models that suppress systemic inflammation, it is not clear whether local resident macrophages in liver, denoted Kupffer cells (KCs), directly contribute to this syndrome. We addressed this question by selectively silencing the expression of the master regulator of inflammation, NF-kB, in KCs in obese mice. We used glucan-encapsulated small interfering RNA particles (GeRPs) that selectively silence gene expression in macrophages in vivo. Following intravenous injections, GeRPs containing siRNA against p65 of the NF-kB complex caused loss of NF-kB p65 expression in KCs without disrupting NF-kB in hepatocytes or macrophages in other tissues. Silencing of NF-kB expression in KCs in obese mice decreased cytokine secretion and improved insulin sensitivity and glucose tolerance without affecting hepatic lipid accumulation. Importantly, GeRPs had no detectable toxic effect. Thus, KCs are key contributors to hepatic insulin resistance in obesity and a potential therapeutic target for metabolic disease.-Tencerova, M., Aouadi, M., Vangala,

Teen and parent perspectives are critical in designing future well-received adolescent-family transition clinics. Development from the ground up with family recommendations may contribute to high-quality health outcomes.

ObjectiveAdipose tissue relies on lipid droplet (LD) proteins in its role as a lipid-storing endocrine organ that controls whole body metabolism. Hypoxia-inducible Gene 2 (Hig2) is a recently identified LD-associated protein in hepatocytes that promotes hepatic lipid storage, but its role in the adipocyte had not been investigated. Here we tested the hypothesis that Hig2 localization to LDs in adipocytes promotes adipose tissue lipid deposition and systemic glucose homeostasis.MethodWhite and brown adipocyte-deficient (Hig2fl/fl × Adiponection cre+) and selective brown/beige adipocyte-deficient (Hig2fl/fl × Ucp1 cre+) mice were generated to investigate the role of Hig2 in adipose depots. Additionally, we used multiple housing temperatures to investigate the role of active brown/beige adipocytes in this process.ResultsHig2 localized to LDs in SGBS cells, a human adipocyte cell strain. Mice with adipocyte-specific Hig2 deficiency in all adipose depots demonstrated reduced visceral adipose tissue weight and increased glucose tolerance. This metabolic effect could be attributed to brown/beige adipocyte-specific Hig2 deficiency since Hig2fl/fl × Ucp1 cre+ mice displayed the same phenotype. Furthermore, when adipocyte-deficient Hig2 mice were moved to thermoneutral conditions in which non-shivering thermogenesis is deactivated, these improvements were abrogated and glucose intolerance ensued. Adipocyte-specific Hig2 deficient animals displayed no detectable changes in adipocyte lipolysis or energy expenditure, suggesting that Hig2 may not mediate these metabolic effects by restraining lipolysis in adipocytes.ConclusionsWe conclude that Hig2 localizes to LDs in adipocytes, promoting adipose tissue lipid deposition and that its selective deficiency in active brown/beige adipose tissue mediates improved glucose tolerance at 23 °C. Reversal of this phenotype at thermoneutrality in the absence of detectable changes in energy expenditure, adipose mass, or liver triglyceride suggests that Hig2 deficiency triggers a deleterious endocrine or neuroendocrine pathway emanating from brown/beige fat cells.

Chronic low-grade white adipose tissue (WAT) inflammation is a hallmark of metabolic syndrome in obesity. Here, we demonstrate that a subpopulation of murine WAT perivascular (PDGFRβ+) cells, termed “fibro-inflammatory progenitors” (FIPs), activate pro-inflammatory signaling cascades shortly after the onset of high-fat diet feeding and regulate pro-inflammatory macrophage accumulation in WAT in a TLR4-dependent manner. FIPs activation in obesity is mediated by the downregulation of ZFP423, identified here as a transcriptional co-repressor of NFκB. ZFP423 suppresses the DNA-binding capacity of the p65 subunit of NFκB by inducing a p300 to NuRD co-regulator switch. Doxycycline-inducible expression of Zfp423 in PDGFRβ+ cells suppresses inflammatory signaling in FIPs and attenuates metabolic inflammation of visceral WAT in obesity. Inducible inactivation of Zfp423 in PDGFRβ+ cells increases FIP activity, exacerbates adipose macrophage accrual, and promotes WAT dysfunction. These studies implicate perivascular mesenchymal cells as important regulators of chronic adipose tissue inflammation in obesity and identify ZFP423 as a transcriptional break on NFκB signaling.

Purpose The purpose of this study is to develop and pilot an innovative behavioral intervention in adolescents with type 1 diabetes mellitus (T1DM) incorporating structured care of a pet to improve glycemic control. Methods Twenty-eight adolescents with A1C > 8.5% (69 mmol/mol) were randomly assigned to either the intervention group (care of a Betta splendens pet fish) or the control group (usual care). Adolescents in the intervention group were given instructions to associate daily and weekly fish care duties with diabetes self-management tasks including blood glucose testing and parent-adolescent communication. Results After 3 months the participants in the intervention group exhibited a statistically significant decrease in A1C levels (−0.5%) compared to their peers in the control group who had an increase in A1C levels (0.8%)(p = 0.04). The younger adolescents (ages 10–13) demonstrated a greater response to the intervention which was statistically significant (−1.5% vs. 0.6%, p = 0.04) compared with the older adolescents (ages 14–17). Conclusions Structured care of a pet fish can improve glycemic control in adolescents with T1DM, likely by providing cues to perform diabetes self-management behaviors.

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