Effect of dietary nutrient profile on plasma glucagon-like peptide-2 in healthy cats

Master of ScienceDepartment of Clinical SciencesMajor Professor Not ListedGlucagon-like peptide-2 (GLP-2) is a meal-induced enteroendocrine hormone responsible for intestinal mucosal growth and repair. GLP-2 secretion in humans and rodents is nutrient-dependent with differential plasma concentrations based on the major nutrient component of a meal. Pre- and post-prandial concentrations of plasma GLP-2 have not been measured in cats. A feasibility study was performed which evaluated whether GLP-2 could be measured in the plasma of client-owned cats, with the secondary hypothesis that the addition of proteinase inhibitor to the plasma samples immediately after collection would increase measured concentrations of GLP-2. A subsequent nutritional study investigated plasma concentrations of GLP-2 in 9 healthy research cats after a fixed calorie meal high in carbohydrates, protein, or fat, with the hypothesis that maximal GLP-2 plasma concentration would occur 30 minutes after the meal, and a high-fat meal would lead to increased plasma GLP-2 concentrations compared to a high-protein or high-carbohydrate meal. In the feasibility study, plasma samples were obtained from 6 fasted client-owned cats at baseline and then one hour after a standardized meal. In the nutritional study, 9 healthy research cats were fasted prior to being fed a calorically standardized meal of 3 different commercial diets relatively high in carbohydrates, protein, or fat. Blood samples were collected at baseline, 30, 60, 75, 90, and 120 minutes after finishing the meal. For both studies, two proteinase inhibitors were added to half of the blood sample immediately after collection. Plasma GLP-2 concentrations were measured using a commercial ELISA. Pre- and post-prandial GLP-2 concentrations and the concentrations of GLP-2 with and without proteinase inhibition were compared using a paired t test. The Friedman test and one-way ANOVA of repeated measures were used to evaluate maximal secretion of GLP-2 within each diet, for non-normally distributed data and normally distributed data, respectively. A mixed analysis of variance with repeated measures was used to evaluate effect of diet on GLP-2 concentrations over time. GLP-2 was detected in all samples. There was no difference between measured GLP-2 concentrations with versus without proteinase inhibitor in either study. Mean GLP-2 concentration 30 minutes after the high-fat meal (1.64 ± 0.23 ng/mL) was significantly higher than at 90 minutes (1.39 ± 0.31 ng/mL; P = 0.029) or 120 minutes (1.44 ± 0.27 ng/mL; P = 0.031) but not significantly different than baseline (1.49 ± 0.28 ng/mL; P = 0.085). There was no difference in pre- or post-prandial GLP-2 concentrations among the high-carbohydrate or high-protein meals. The results of this study suggest that a meal high in fat provides a stimulus for GLP-2 secretion in cats, while meals high in protein and carbohydrate do not. Proteinase inhibition does not affect GLP-2 measurement using this commercial ELISA

BAG3 Is a Modular, Scaffolding Protein that physically Links Heat Shock Protein 70 (Hsp70) to the Small Heat Shock Proteins

Small heat shock proteins (sHsps) are a family of ATP-independent molecular chaperones that are important for binding and stabilizing unfolded proteins. In this task, the sHsps have been proposed to coordinate with ATP-dependent chaperones, including heat shock protein 70 (Hsp70). However, it is not yet clear how these two important components of the chaperone network are linked. We report that the Hsp70 co-chaperone, BAG3, is a modular, scaffolding factor to bring together sHsps and Hsp70s. Using domain deletions and point mutations, we found that BAG3 uses both of its IPV motifs to interact with sHsps, including Hsp27 (HspB1), αB-crystallin (HspB5), Hsp22 (HspB8), and Hsp20 (HspB6). BAG3 does not appear to be a passive scaffolding factor; rather, its binding promoted de-oligomerization of Hsp27, likely by competing for the self-interactions that normally stabilize large oligomers. BAG3 bound to Hsp70 at the same time as Hsp22, Hsp27, or αB-crystallin, suggesting that it might physically bring the chaperone families together into a complex. Indeed, addition of BAG3 coordinated the ability of Hsp22 and Hsp70 to refold denatured luciferase in vitro. Together, these results suggest that BAG3 physically and functionally links Hsp70 and sHsps

Evaluation of serum 25‐hydroxyvitamin D, C‐reactive protein, and haptoglobin as biomarkers in dogs newly diagnosed with histoplasmosis

Abstract Background Serum 25‐hydroxyvitamin (OH)D, C‐reactive protein (CRP), and haptoglobin are useful biomarkers in various infectious diseases and inflammatory disorders in dogs, but their utility in histoplasmosis is unknown. Objective Determine if serum 25(OH)D, CRP, and haptoglobin concentrations are different in dogs with histoplasmosis compared to healthy controls and whether serum globulin, albumin, CRP, or haptoglobin are associated with 25(OH)D concentration. Animals Twenty‐two client‐owned dogs (histoplasmosis, n = 12; controls, n = 10). Methods Prospective case‐control study. Dogs with histoplasmosis were categorized as pulmonary, disseminated, or gastrointestinal (GI) tract. Serum 25(OH)D was measured using modified high‐performance liquid chromatography (HPLC). Serum CRP and haptoglobin were measured with ELISA assays. Results Dogs with histoplasmosis were grouped as disseminated (n = 8) and GI tract (n = 4). No dogs had pulmonary tract involvement alone. Dogs with histoplasmosis (median, interquartile range [IQR]; 11.6 ng/mL, 16.8) had lower serum 25(OH)D concentrations than controls (35.7 ng/mL, 17.6; P < .001). Serum CRP and haptoglobin concentrations were higher in dogs with histoplasmosis (CRP: median, IQR; 63.5 mg/L, 37.1 and haptoglobin: 459.7 mg/dL, 419.6) than controls (CRP: 1.9 mg/L, 2; P < .001 and haptoglobin: 85.5 mg/dL, 106.7; P = .003). Serum 25(OH)D concentration was positively associated with fold change in serum albumin concentration (ρ = 0.77; P < .001), and negatively associated with fold change in serum globulin (ρ = −0.61; P = .003) and CRP concentrations (ρ = −0.56; P = .01). Conclusion and Clinical Importance Assay of serum 25(OH)D, CRP, and haptoglobin could have clinical value in dogs with histoplasmosis

BAG3 Is a Modular, Scaffolding Protein that physically Links Heat Shock Protein 70 (Hsp70) to the Small Heat Shock Proteins

Small heat shock proteins (sHsps) are a family of ATP-independent molecular chaperones that are important for binding and stabilizing unfolded proteins. In this task, the sHsps have been proposed to coordinate with ATP-dependent chaperones, including heat shock protein 70 (Hsp70). However, it isn’t yet clear how these two important components of the chaperone network are linked. We report that the Hsp70 co-chaperone, BAG3, is a modular, scaffolding factor to bring together sHsps and Hsp70s. Using domain deletions and point mutations, we confirmed that BAG3 uses both of its IPV motifs to interact with sHsps, including Hsp27 (HspB1), αB-crystallin (HspB5), Hsp22 (HspB8) and Hsp20 (HspB6). BAG3 does not appear to be a passive scaffolding factor; rather, its binding promoted de-oligomerization of Hsp27, likely by competing for the self-interactions that normally stabilize large oligomers. BAG3 bound to Hsp70 at the same time as either Hsp22, Hsp27 or αB-crystallin, suggesting that it might physically bring the chaperone families together into a complex. Indeed, addition of BAG3 coordinated the ability of Hsp22 and Hsp70 to refold denatured luciferase in vitro. Together, these results suggest that BAG3 physically and functionally links Hsp70 and sHsps