SUMMARY Molecular signatures have identified several subsets of Diffuse Large B-Cell Lymphoma (DLBCL) and rational targets within the B-cell receptor (BCR) signaling axis. The OxPhos-DLBCL subset, which harbors the signature of genes involved in mitochondrial metabolism, is insensitive to inhibition of BCR survival signaling, but is functionally undefined. We show that compared with BCR-DLBCLs, OxPhos-DLBCLs display enhanced mitochondrial energy transduction, greater incorporation of nutrient-derived carbons into the TCA cycle and increased glutathione levels. Importantly, perturbation of the fatty acid oxidation program and glutathione synthesis proved selectively toxic to this tumor subset. Our analysis provides evidence for distinct metabolic fingerprints and associated survival mechanisms in DLBCL and may have therapeutic implications.

Summary Neuronal excitation can be substantially modulated by alterations in metabolism, as evident from the anticonvulsant effect of diets that reduce glucose utilization and promote ketone body metabolism. We provide genetic evidence that BAD, a protein with dual functions in apoptosis and glucose metabolism, imparts reciprocal effects on metabolism of glucose and ketone bodies in brain cells. These effects involve phospho-regulation of BAD and are independent of its apoptotic function. BAD modifications that reduce glucose metabolism produce a marked increase in the activity of metabolically sensitive KATP channels in neurons, as well as resistance to behavioral and electrographic seizures in vivo. Seizure resistance is reversed by genetic ablation of the KATP channel, implicating the BAD-KATP axis in metabolic control of neuronal excitation and seizure responses.

SUMMARY The homeostatic balance of hepatic glucose utilization, storage and production is exquisitely controlled by hormonal signals and hepatic carbon metabolism during fed and fasted states. How the liver senses extracellular glucose to cue glucose utilization versus production is not fully understood. Here, we show that the physiologic balance of hepatic glycolysis and gluconeogenesis is regulated by BAD, a dual function protein with roles in apoptosis and metabolism. BAD deficiency reprograms hepatic substrate and energy metabolism towards diminished glycolysis, excess fatty acid oxidation and exaggerated glucose production that escapes suppression by insulin. Genetic and biochemical evidence suggest that BAD’s suppression of gluconeogenesis is actuated by phosphorylation of its BH3 domain and subsequent activation of glucokinase. The physiologic relevance of these findings is evident from the ability of a BAD phospho-mimic variant to counteract unrestrained gluconeogenesis and improve glycemia in leptin resistant and high-fat diet models of diabetes and insulin resistance.

SUMMARY Strategies that simultaneously enhance the survival and glucose responsiveness of insulin-producing β cells will greatly augment β cell replacement therapies in type 1 diabetes (T1D). We show that genetic and pharmacologic mimetics of the phosphorylated BCL-2 homology 3 (BH3) domain of BAD impart β cell autonomous protective effects in the face of stress stimuli relevant to β cell demise in T1D. Importantly, these benefits translate into improved engraftment of donor islets in transplanted diabetic mice, increased β cell viability in islet grafts, restoration of insulin release, and diabetes reversal. Survival of β cells in this setting is not merely due to the inability of phospho-BAD to suppress pro-survival BCL-2 proteins but requires its activation of the glucose-metabolizing enzyme glucokinase. Thus, BAD phospho-BH3 mimetics may prove useful in restoration of functional β cell mass in diabetes.

Background The Dog Erythrocyte Antigen (DEA) 1 blood group system remains poorly defined. Objectives The purpose of the study was to determine the DEA 1 mode of inheritance and to characterize the DEA 1 antigen and alloantibodies. Animals Canine research colony families, clinic canine patients, and DEA 1.2+ blood bank dogs were studied. Methods Canine blood was typed by flow cytometry and immunochromatographic strips using anti-DEA 1 monoclonal antibodies. Gel column experiments with polyclonal and immunoblotting with monoclonal anti-DEA 1 antibodies were performed to analyze select samples. Cross-reactivity of human typing reagents against canine RBCs and one monoclonal anti-DEA 1 antibody against human RBC panels was assessed. Results Typing of 12 families comprising 144 dogs indicated an autosomal dominant inheritance with ≥4 alleles: DEA 1− (0) and DEA 1+ weak (1+), intermediate (2+) and strong (3+ and 4+). Samples from 6 dogs previously typed as DEA 1.2+ were typed as DEA 1+ or DEA 1− using monoclonal antibodies. Human typing reagents produced varied reactions in tube agglutination experiments against DEA 1+ and DEA 1− RBCs. Polypeptide bands were not detected on immunoblots using a monoclonal anti-DEA 1 antibody, therefore the anti-DEA 1 antibody may be specific for conformational epitopes lost during denaturation. Conclusions The autosomal dominant inheritance of DEA 1 with ≥4 alleles indicates a complex blood group system; the antigenicity of each DEA 1+ type will need to be determined. The biochemical nature of the DEA 1 antigen(s) appears different from human blood group systems tested.

No abstract

Background: Erythrocyte microcytosis in some dogs with hepatocellular carcinoma (HCC) suggests a derangement in systemic iron. Hepcidin, the master regulator of iron, is secreted by the liver in response to interleukin 6 (IL-6) and/or bone morphogenetic protein 6 (BMP6) and can cause microcytosis.Objectives: Pilot study to compare the quantities of hepcidin, IL-6, and BMP6 RNA molecules in archival tumoral (HCC) and adjacent peritumoral (non-HCC) hepatic tissue to determine if they are different between tissue types or associated with microcytosis.Methods: RNA was isolated from formalin-fixed, paraffin-embedded HCC and non-HCC tissue from seven microcytic dogs and four normocytic dogs. Digital RNA counts of hepcidin, IL-6, or BMP6, and six other iron-regulatory genes were determined using the Nanostring nCounter system. The area of blue on each section was digitally evaluated to measure the extent of Prussian blue staining objectively. Parameters were compared between HCC and non-HCC tissue and between microcytic and normocytic groups.Results: Hepcidin was decreased, and transferrin receptor 1 (TfR1) was increased in HCC tissue compared with non-HCC tissue. Non-HCC hepcidin RNA counts correlated negatively with MCV and positively with the extent of iron staining. Hepcidin expression was higher in non-HCC tissue of microcytic cases than in normocytic cases.Conclusions: Canine HCC cases showed relatively increased iron staining in non-HCC tissue and decreased hepcidin RNA in HCC tissue. Microcytic cases had higher hepcidin RNA in non-HCC tissue than normocytic cases. Future studies may extend these findings to protein quantification, cellular localization of RNA changes, and determining if iron loading in canine liver is a predisposing factor for HCC.

No abstract