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Adipocyte-mediated inflammatory signalling has been proposed to alter adipose physiology in obesity and Type 2 diabetes mellitus. Novel targets for alteration of inflammatory signalling are needed to improve obesity-related outcomes. The γ-secretase enzyme complex has been suggested to play a role both in adipocyte function as well as in immune regulation. We hypothesized that adipocyte-specific γ-secretase inhibition could alter the inflammatory makeup of adipose tissue. We found that genetic blockade of γ-secretase in adipocytes leads to a decrease in EMR1 (F4/80) expression, as a marker of macrophage presence, in adipose tissue without changes in expression of markers of other inflammatory cell types. To explore the mechanism by which adipocytes can alter macrophage function in vitro, fully differentiated 3T3-L1 adipocytes were treated with a γ-secretase inhibitor in the presence of lipopolysaccharide (LPS) and transcription of IL6 and ccl2 (MCP1) were quantified. IL-6 expression and secretion were significantly inhibited by γ-secretase blockade, with little effect on MCP1. Preconditioned media from 3T3-L1 adipocytes treated with a γ-secretase inhibitor also alters macrophage activation but did not affect macrophage translocation in vitro. Therefore, γ-secretase inhibition in fully differentiated adipocytes can alter IL-6 signalling to macrophages, consistent with our hypothesis that that γ-secretase is involved in adipocyte-initiated inflammatory signalling cascades. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to investigate the relationships between regulatory changes, returns on equity and stock market valuations for Canadian food and non-food agribusinesses. Design/methodology/approach – Two empirical approaches are employed. First, an event study is used to evaluate the impact of official regulatory announcements on the stock market valuations of selected Canadian agribusinesses. Next, an approach introduced by Mishra et al. using the Du Pont expansion is applied to investigate the effect of regulations on firms' accounting profits. Data on Canadian food and non-food agribusinesses are collected from Bloomberg, Thompson One Banker and SEDAR. Findings – The event study demonstrates that official regulatory announcement dates do not correspond with abnormal stock market returns for Canadian firms, while the Du Pont model yields mixed evidence with respect to their accounting profits. Research limitations/implications – This paper only considers publicly traded companies. As a result, survivorship bias may exist. Future research should include privately held and cooperative firms. Social implications – Food regulations can influence firm profits and shareholder wealth, so understanding how government actions influence agribusiness is important when considering the total costs of current and future food policy. Originality/value – The interaction between policy and the financial performance of Canada's publicly traded agribusinesses is an under-researched area and no studies have examined Canadian data. The results of this study are valuable to both policy makers and researchers. [ABSTRACT FROM AUTHOR]

The insulin-responsive glucose transporter, GLUT4, is regulated in various physiologic states at the transcriptional level. When expressed in transgenic mice, the human GLUT4 promoter is governed by two cis-acting sequences: an MEF2 binding domain and Domain I, that function both as positive and negative regulators depending on the physiologic state. MEF2 proteins and GLUT4 enhancer factor (GEF) are known ligands for these cis-acting elements, but their mechanism of action is unclear. To begin to understand this important process, we have characterized GEF structural domains and its interactions with the MEF2A isoform. We find that the C terminus of GEF comprises its DNA-binding domain, but does not contribute to GEF homo-oligomerization. We also have found that GEF dimerizes with increased affinity to a hypophosphorylated form of MEF2A. Furthermore, we demonstrated that MEF2A binding to its cognate binding site can increase the DNA binding activity of GEF to Domain I, suggesting a novel mechanism for MEF2A transcriptional activation. Finally, we have demonstrated that the transcriptional co-repressor HDAC5 can interact with GEF in the absence of MEF2 proteins and specifically inhibit GLUT4 promoter activity. These findings lead to the hypothesis that GEF and the MEF2 proteins form a complex on the GLUT4 promoter that allows for recruitment of transcriptional co-regulators (repressors and/or activators) to control GLUT4 promoter activity. [ABSTRACT FROM AUTHOR]

GLUT4 promoter activity is regulated by hormonal, metabolic, and tissue-specific controls. This complicates the study of GLUT4 gene transcription, as no cell culture model adequately recapitulates these extracellular regulators. While investigating cultured primary adipocytes as a model system for GLUT4 transcription, we observed that GLUT4 mRNA was specifically and rapidly downregulated upon tissue dispersal. Downregulation of GLUT4 mRNA was mediated in part by loss of regulatory control by the trans-acting factors that control GLUT4 transcriptional activity [the myocyte enhancer factor 2 (MEF2) transcription factor family and the GLUT4 enhancer factor] and their cognate DNA binding sites in transgenic mice. The differences in GLUT4 transcription when whole adipose tissue and cell culture model systems are compared can be correlated to a posttranslational phosphorylation of the transcription factor MEF2A. The difference in the MEF2A phosphorylation state in whole tissue vs. isolated cells may provide a further basis for the development of an in vitro system that could recapitulate fully regulated GLUT4 promoter activity. Development of an in vitro system to reconstitute GLUT4 transcriptional regulation will further efforts to discern the molecular mechanisms that underlie GLUT4 expression. [ABSTRACT FROM AUTHOR]

As the primary glucose transporter in skeletal muscle, GLUT4 is an important factor in the regulation of blood glucose. We previously reported that stimulation of AMP-activated protein kinase (AMPK) with 5-antinoimi-dazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) increased GLUT4 expression in muscle. GLUT4 enhancer factor (GEF) and myocyte enhancer factor 2 (MEF2) have been shown to be important for normal GLUT4 expression because deletion or truncation of the consensus sequences on the promoter causes depressed GLUT4 mRNA expression. This led to the current study to investigate possible roles for GEF and MEF2 in mediating the activation of GLUT4 gene transcription in response to AMPK. Here we show that, although AMPK does not appear to phosphorylate MEF2A, AMPK directly phosphorylates the GEF protein in vitro, MEF2 and GEF are activated in response to AMPK as we observed translation of both to the nucleus after AICAR treatment. Nuclear MEF2 protein content was increased alter 2 h, and GEF protein was increased in the nucleus 1 and 2 h post-AICAR treatment. Last, GEF and MEF2 increase in binding to the GLUT4 promoter within 2 h after AICAR treatment. Thus we conclude that GEF and MEF2 mediate the AMPK-induced increase in transcription of skeletal muscle GLUT4, AMPK can phosphorylate GEF and in response to AICAR, GEF, and MEF2 translocate to the nucleus and have increased binding to the GLUT4 promoter. [ABSTRACT FROM AUTHOR]

Studies the novel role for a histidine-containing phosphotransfer (HPt) domain in stabilizing the phosphorylated state of a response regulator domain. Phosphorylation of response regulator domains; Half-lives of phosphorylated response regulator domains in the absence or presence of YPD1 proteins.

As part of studies to understand human pancreatic islet pathophysiology in type 1 diabetes (T1D), we discovered normal β cell mass in a 33-year-old deceased organ donor with T1D for 17 years. Further analysis revealed the donor's diabetes resulted from a causative variant in hepatic nuclear factor 1-alpha (HNF1A), associated with Maturity-onset Diabetes of the Young-3 (MODY3) (J Clin Invest 129:246, 2019), which can be treated with sulfonylureas. Review of the donor's redacted medical chart suggested a family history of diabetes consistent with the known autosomal dominant pattern of inheritance of MODY3. With this clinically-actionable information, we desired to inform the donor's family. However, de-identified samples are not considered "human subject" research by Institutional Review Boards (IRB), so the family's identity was unknown with no defined pathway for communicating these findings. Working with a Human Tissue and Organ Research Resource and an organ procurement organization, we developed a new, IRB-approved communication path between those involved in tissue collection, scientific investigation, and the donor's family and physician. This allowed targeted genetic testing of potentially affected family members, which revealed five living relatives of the donor who carried the HNF1A variant: three adults diagnosed with diabetes before the age of 25 currently treated with insulin and two children (ages 6 months and 3 years) who did not have clinical diabetes. Since none of the identified individuals were known to have MODY3, they will likely benefit from appropriate clinical care and surveillance. This experience demonstrates the need for the scientific community to develop guidelines to address handling, reporting, and use of research findings from de-identified tissue collected for research. Defining ethical avenues for donor family-investigator communications will benefit for both organ donor families and scientific research. Disclosure: D. Sparling: None. R. Haliyur: None. J. Lindner: None. L. Weber: None. A. Ramirez: None. M. Brissova: None. A.C. Powers: None. [ABSTRACT FROM AUTHOR]

Presents a study that determined whether exercise increases the DNA-binding activity of both myocyte enhancer factor 2 (MEF2) and glucose transporter isoform 4 (GLUT4) enhancer factor (GEF) in human skeletal muscle. Findings of the study; Conclusions and significance of the study.

Real-time continuous glucose monitoring (rtCGM) can directly improve patient outcomes, including decreased health care system utilization and associated costs. The purpose of this study was to evaluate the clinical benefits of rtCGM use in a high-risk, under-resourced cohort of adolescents and young adults (AYA) with type 1 diabetes (T1D) who had no prior access to rtCGM. The effects of rtCGM use on hemoglobin A1c (A1c) and the frequency of health care events (i.e., diabetes-related emergency room (ER) visits, hospitalizations, emergency medical services (EMS), and after-hour emergency calls) were evaluated regarding payor costs in 33 AYA with ≥70% rtCGM use. Secondary aims included the evaluation of a phone-based pattern management intervention. The frequency of health care events decreased at 12 and 24 weeks for all participants, and there was no significant difference by treatment group. We estimated that the use of rtCGM in this cohort results in a projected annualized cost-savings of $195,943 to $294,864 or 43–65% per year based on Medicare or list pricing for rtCGM, respectively. Results also revealed improvements in A1c at 12 weeks for all study participants, but this was not maintained at 24 weeks for the phone-based pattern management intervention group. Our findings suggest that rtCGM may be an effective tool for reducing diabetes-related events and underscores the importance of access. Future studies are needed to further examine tailored interventions and support to optimize rtCGM use and glycemic health in high-risk AYA. [ABSTRACT FROM AUTHOR]

Glucose import down its concentration gradient via the glucose transporter GLUT4 is one of the primary physiologic roles of the insulin-signaling cascade. Insulin sensitivity is therefore highly correlated with the levels of GLUT4 protein in adipose and muscle tissues. GLUT4 expression is known to be regulated by diverse tissue-specific, hormonal, and/or metabolic controls, and a loss of GLUT4 protein in diabetes mellitus has been correlated to a decrease in the transcriptional rate. Elucidating the molecular mechanisms that control the GLUT4 promoter could therefore aid in the search for new interventions for insulin resistance and diabetes. Our work has previously identified two of the cis-acting sites within the smallest functional GLUT4 promoter as well as the transcription factors binding those sites, namely the MEF2-family members MEF2A and MEF2D, and the GLUT4 Enhancer Factor (GEF). We have also recently identified a post-translational modification of MEF2A that correlates with a model of decreased GLUT4 promoter activity. We are examining whether an observed hyperphosphorylation event occurs within insulin-responsive tissues under the streptozotocin-induced diabetic phenotype. Interestingly, hyperphosphorylation correlates with increased cytoplasmic localization of MEF2A in transfected cells, suggesting that hyperphosphorylation regulates nuclear MEF2A concentration. Previously, we observed that MEF2A and GEF function cooperatively to regulate GLUT4 gene expression. Using a biotinylated oligonucleotide corresponding to a truncated GLUT4 promoter that MEF2A and GEF interact with their cognate binding sites cooperatively, thus providing a molecular mechanism to account for the functional cooperativity. Further examination of the regulatory elements governing GLUT4 expression in vivo and in vitro will lead to the development of an system that recapitulates all the essential molecular mechanisms that control GLUT4 promoter activity, aiding in further study of potential therapeutics. ADA-Funded Research [ABSTRACT FROM AUTHOR]

Risk balancing refers to the balancing of business risk (BR) and financial risk (FR) by firms through their investment and borrowing decisions. Assuming the concept holds, a decrease in income variability (BR) prompts the firm to incur greater debt levels thereby increasing FR. Reducing (BR), which continues to be the central objective of Canadian agricultural policy through programs such as Canadian Agricultural Income Stabilization Program (CAIS)/AgriStability, may lead farmers to take on more FR than they would take otherwise, which, in turn, increases the risk of equity loss. However, it is not known whether Canadian business risk management (BRM) programs offset BR as intended, and whether any potential reduction leads to increased FR (risk balancing) and possibly higher levels of overall risk for individual farm operations. This paper represents the first attempt to shed light on whether Canadian BRM programs fail to reduce farm risk as a result of farmers' risk balancing behavior using a longitudinal farm-level data set from Ontario. Results are mixed: (1) BRM payments reduce BR for beef farms but not for field crops farms (though the latter result may be due to the lack of data on Crop Insurance payments); (2) risk balancing holds particularly for the larger farms, and (3) BRM programs overall have no significant effect on the likelihood of increased debt use for either sector, on average; however, participation in CAIS/AgriStability increases the probability that farms take on more debt than they would take otherwise for both sectors. Further analysis is needed to determine whether BRM programs increase the probability of default for farms. [ABSTRACT FROM AUTHOR]

Youth with type 1 diabetes (T1D) require 24/7 access to T1D management supplies. This study aims to characterize access to T1D supplies when youth are away from home. We emailed a comprehensive survey to 4756 parents of T1D Exchange participants <18 years old; 752 respondents completed the survey (83% completed by parents). Results were age-stratified: <6 (N=21), 6-12 (N=271) and 13-18 (N=459). The majority of youth carry rapid-acting insulin most of the time or always, yet the proportion decreases as age increases (Table 1). ≥80% of injection users carry an extra pen or syringe, while >55% of pump users carry an extra infusion set. Among CGM users, 100% of ≤6 years old vs. 67% of adolescents carry a receiver or phone; 33% of 13-18 years old never carry an extra sensor. 38% of youth ≤6 years old vs. 27% of teens carry blood or urine ketone testing supplies. In total, 64% reported carrying glucose tablets or gel; 87% carry another rapid acting carbohydrate. 64% of respondents carry glucagon, again decreasing across adolescence. Over 2/3 carry at least one form of T1D identification. Technology to optimize glycemic control and detect/prevent acute complications of T1D have improved. Yet, adolescents are less likely than younger T1D-affected youth, to carry supplies to detect, prevent and/or treat acute events. These findings call for novel and ongoing T1D emergency preparedness training to strike a balance between supervision and autonomy of adolescents. Disclosure: M. Quinn: None. R. Bailey: None. N.C. Foster: None. J. Simmons: None. E. Eyth: None. H. Rodriguez: Research Support; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Bristol-Myers Squibb Company, Daiichi Pharm Corp, MannKind Corporation, Medtronic MiniMed, Inc. Research Support; Spouse/Partner; Medtronic MiniMed, Inc. Research Support; Self; Takeda Pharmaceutical Company Limited. Other Relationship; Self; Merck & Co., Inc., Novartis Pharmaceuticals Corporation, Novo Nordisk Inc. S. Corathers: None. C.J. Levy: Advisory Panel; Self; Novo Nordisk A/S, Sanofi. Employee; Spouse/Partner; Allergan. N.M. Sheanon: None. R.M. Wasserman: None. D. Sparling: None. D. Adkins: None. A. Albanese-O'Neill: None. D.J. DeSalvo: Consultant; Self; Dexcom, Inc., Insulet Corporation. Funding: The Leona M. and Harry B. Helmsley Charitable Trust [ABSTRACT FROM AUTHOR]