Characterization of metabolic alterations in the lean metabolically unhealthy alpha defensin transgenic mice - PubMed (original) (raw)
. 2024 Jan 12;27(2):108802.
doi: 10.1016/j.isci.2024.108802. eCollection 2024 Feb 16.
Emad Maraga 1, Saja Baraghithy 2, Shiran Udi 2, Shahar Azar 2, Ann Saada 3 4 5, Benjamin Glaser 6, Dana Avrahami 7, Suhair Abdeen 1, Zenab Hamdan 6, Joseph Tam 2, Rami Abu Fanne 1 8
Affiliations
- PMID: 38318380
- PMCID: PMC10839648
- DOI: 10.1016/j.isci.2024.108802
Characterization of metabolic alterations in the lean metabolically unhealthy alpha defensin transgenic mice
Abd Al-Roof Higazi et al. iScience. 2024.
Abstract
Inflammation is consistently linked to dysmetabolism. In transgenic mice (Def+/+) model the neutrophilic peptide, alpha defensin, proved atherogenic. This phenotype occurred despite favorable cholesterol and glucose levels, and lower body weight and blood pressure. In this study, integration of metabolic&behavioral phenotyping system, endocrine, biochemical and mitochondrial assessment, pathological and immunohistochemical tests, and multiple challenge tests was established to explore the metabolic impact of alpha defensin. Compared to the control group, Def+/+ mice exhibited lower total energy expenditure and carbohydrate utilization, and higher fat oxidation. Their ACTH-cortisol and thyroid profiles were intact. Intriguingly, they had low levels of glucagon, with high ammonia, uric acid, triglyceride, and lactate. Mitochondrial evaluations were normal. Overall, defensin-induced hypoglucagonemia is associated with lipolysis, restricted glucose oxidation, and enhanced wasting. Def+/+ mice may be a useful model for studying the category of lean, apparently metabolically healthy, and atherosclerotic phenotype, with insight into a potential inflammatory-metabolic link.
Keywords: Cell biology; Endocrinology; Molecular physiology.
© 2024 The Author(s).
Conflict of interest statement
The authors declare no competing interests.
Figures
Graphical abstract
Figure 1
Impact of Alpha Defensin on Body Weight and Composition (A) macroscopic comparison of WT and Def+/+ mice at 8 months of age. WT (left, 43g) and Def+/+ mice (right, 24.5g) mice are shown. (B and C) Abdominal ventral view of dissected mice depicting the fat pads of WT mouse (B) surrounded by large fat pads extending until the urinary bladder, with developed epididymal fat pads that cover up the inferior abdominal cavity, and Def+/+ mouse (C) with nearly zero fat pads. The liver, kidney, and inferior vena cava are also shown. (D) Body composition measurements of Def+/+ and WT mice (n = 8) using the EchoMRI analyzer. (E) Liver composition measurements of Def+/+ and WT mice using the EchoMRI- analyzer. (F) Body weight of WT (black) and Def+/+ (gray) mice (n = 7) measured over the indicated time course. All bar graphs are presented as mean ± SD, and the p values were evaluated by unpaired _t_-test (∗p value< 0.05).
Figure 2
Full metabolic profile of Def+/+ mice Alpha defensin overexpression is associated with significantly lower TEE (A), coupled with reduced respiratory exchange rate (RER; B), reflected by reduced VO2 and VCO2 (C and D, respectively). Additionally, Def+/+ mice exhibited higher fat oxidation during the night period (E), and lower carbohydrate oxidation (F). Data are presented as mean ± SEM from 4 mice per group and the p values were evaluated by unpaired t-test. ∗p < 0.05 vs. WT, ∗∗∗P< vs. WT, ∗∗∗∗p < 0.0001 vs. WT.
Figure 3
Def+/+ mice have an elevated activity profile compared to their WT littermates Def+/+ mice demonstrated a higher total ambulatory activity (A). Additionally, Def+/+ mice show elevated levels in voluntary locomotion (B), pedestrian locomotion speed (C), and total traveled distance (D). Data are presented as mean ± SEM from 4 mice per group and the p values were evaluated by unpaired t-test. ∗p < 0.05 vs. WT, ∗∗∗p < 0.001 vs. WT, ∗∗∗∗p < 0.0001 vs. WT.
Figure 4
Def+/+ mice have an elevated wheel running and voluntary activity profile compared to their WT littermates Def+/+ mice demonstrate a higher total wheel running (A), and wheel speed (B). Additionally, Def+/+ mice showed increased tendency toward voluntary activities as shown in the time budget (% time toward different activities; C). Data are presented as mean ± SEM from 4 mice per group and the p values were evaluated by unpaired t-test. ∗∗p < 0.01 vs. WT, ∗∗∗<0.001 vs. WT, ∗∗∗∗p < 0.0001 vs. WT.
Figure 5
Def+/+ mice consume less food Def+/+ mice demonstrated lower food intake during both the light and dark hours. Meal size (A and B), cumulative food intake (C), and sum of food consumed (D). Data are presented as mean ± SEM from 4 mice per group and the p values were evaluated by unpaired t-test. ∗p < 0.05 vs. WT.
Figure 6
Normal mitochondrial function in Def+/+ mice (A) Quantitative amino acids analysis from pooled plasma samples (n = 4). (B) I–III, representative PAS, Immunofluorescence (×200, Scale bar: 100 μm), and electron microscopy images (Scale bar: 2.5 μm), respectively, of WT liver slides at the age of 8months (n = 6). IV–VI are representative PAS, Immunofluorescence, and electron microscopy images, respectively, of Def+/+ liver slides at the age of 8months (n = 6). ∗, mitochondria; N, nucleus; LD, lipid droplet; arrowhead, glycogen (black dots). (C) Respiratory chain and citrate synthase activities in liver mitochondria (n = 3). Data are presented as mean ± SEM from 3 mice per group and the p values were evaluated by unpaired t-test. ∗p < 0.05 vs. WT. CI-complex I; CII (SDH)-complex II (Succinate dehydrogenase); CIII-complex III; CIV (COX)-complex IV (Cytochrome c Oxidase); CS- citrate synthase.
Figure 7
Imbalanced circulating hormone levels in Def+/+ mice (A) Fasting cortisol and ACTH levels in both strains at 4 and 8 months of age (n = 8). (B) Fasting glucagon levels in both strains at 8 months of age. Data are presented as mean ± SD and the p values were evaluated by unpaired t-test. ∗p < 0.05 vs. WT.
Figure 8
Metabolic challenge tests revealed an ambivalent glucose tolerance pattern in Def+/+ mice (A) ipGTT and (B) ipITT curves in both strains. (C) Glucose response to an IP injection of glucagon. Data are presented as mean ± SD from 6 mice per group, and the p values were evaluated by unpaired t-test. ∗p < 0.05 vs. WT.
Figure 9
Suppressed glucagon secretion, but not production, is associated with the overexpression of alpha defensin (A–C) Pancreatic islet sections were immunostained using glucagon antibodies, with brown staining indicating the presence of the hormone. The images in (A) show a higher abundance of glucagon in Def+/+ islets compared to WT (C). Representative images of islets from 8-month-old Def+/+ (B) and WT mice (D) were co-stained with immunofluorescence for insulin (green) and glucagon (red), with nuclear staining (blue) performed with DAPI. Scale bars represent 25 μm. Cell composition in Def+/+ (gray) and WT mice (black) is shown in (E), while (F) displays the glucagon content per gram pancreas per gram body weight in 8-months-old mice (n = 4). (G) shows the total glucagon content obtained after KCl effect. Alpha defensin effect on the glucose suppression of glucagon secretion (GSGS) in human islets is depicted in (H), with KCl administration shown in gray bars with alpha defensin. Alpha defensin concentration for incubation was 13.8 μL = 100 nM for 1 mL. (I) Glucose induction of insulin secretion in human islets, with (gray) and without (black) alpha-defensin incubation, and with KCl administration. Alpha-defensin concentration for incubation was 13.8 μL = 100 nM for 1 mL. Data are presented as mean ± SD and the p values were evaluated by unpaired t-test. ∗p < 0.05 vs. WT.
References
- Wilson P.W.F., D'Agostino R.B., Parise H., Sullivan L., Meigs J.B. Metabolic syndrome as a precursor of cardiovascular disease and type 2 diabetes mellitus. Circulation. 2005;112:3066–3072. - PubMed
- Wilson P.W., Kannel W.B., Silbershatz H., D'Agostino R.B. Clustering of metabolic factors and coronary heart disease. Arch. Intern. Med. 1999;159:1104–1109. - PubMed
- Eckel N., Mühlenbruch K., Meidtner K., Boeing H., Stefan N., Schulze M.B. Characterization of metabolically unhealthy normal-weight individuals: Risk factors and their associations with type 2 diabetes. Metabolism. 2015;64:862–871. - PubMed
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