3 research outputs found
Transcriptomic and Functional Analyses on the Effects of Dioxin on Insulin Secretion of Pancreatic Islets and β‑Cells
In
this study, transcriptomic and Ingenuity Pathway Analysis (IPA)
underlined that an ex-vivo TCDD treatment (0.1 nM) stimulated insulin-release
in mouse pancreatic islets via the effect on the Akt-mTOR-p70S6K,
AMPK and ERK1/2 pathways. Functional studies using both ex-vivo islets
and the mouse β-cell-line (Min-6) validated the stimulatory
effects of TCDD (0.1 and 1 nM) on basal-insulin secretion. At 0.1
nM TCDD treatment on Min-6, Western blot analysis showed activation
of ERK1/2 and decreased expression of pyruvate dehydrogenase kinase
(PDK). A reduction of PDK expression is associated with an increase
of pyruvate dehydrogenase flux. This observation was supported by
the detection of significantly higher cellular ATP levels, an increase
of glucose-stimulated-insulin-secretion (GSIS), and an inhibition
of the AMPK pathway. At 1 nM TCDD treatment on Min-6, significant
inhibitions of the Akt-mTOR pathway, cellular ATP production, and
GSIS were evident. The experimental studies in Min-6 supported the
IPA of transcriptomic data in pancreatic islets. Collectively, TCDD
treatment caused an elevated basal-insulin release in both islets
and β-cell cultures. Moreover, our data revealed that the modulation
of the Akt-mTOR-p70S6K, AMPK and ERK1/2 pathways might be an important
component of the mechanism for the TCDD-perturbing effects on ATP
production in β-cells in affecting insulin secretion
Effects of <i>In Utero</i> PFOS Exposure on Epigenetics and Metabolism in Mouse Fetal Livers
Prenatal exposure
to perfluorooctanesulfonate (PFOS)
increases
fetus’ metabolic risk; however, the investigation of the underlying
mechanism is limited. In this study, pregnant mice in the gestational
days (GD, 4.5–17.5) were exposed to PFOS (0.3 and 3 μg/g
of body weight). At GD 17.5, PFOS perturbed maternal lipid metabolism
and upregulated metabolism-regulating hepatokines (Angptl4,
Angptl8, and Selenop). Mass-spectrometry imaging and whole-genome
bisulfite sequencing revealed, respectively, selective PFOS localization
and deregulation of gene methylation in fetal livers, involved in
inflammation, glucose, and fatty acid metabolism. PCR and Western
blot analysis of lipid-laden fetal livers showed activation of AMPK
signaling, accompanied by significant increases in the expression
of glucose transporters (Glut2/4), hexose-phosphate
sensors (Retsat and ChREBP), and
the key glycolytic enzyme, pyruvate kinase (Pk) for
glucose catabolism. Additionally, PFOS modulated the expression levels
of PPARα and PPARγ downstream target genes, which simultaneously
stimulated fatty acid oxidation (Cyp4a14, Acot, and Acox) and lipogenesis (Srebp1c, Acaca, and Fasn). Using human normal hepatocyte
(MIHA) cells, the underlying mechanism of PFOS-elicited nuclear translocation
of ChREBP, associated with a fatty acid synthesizing pathway, was
revealed. Our finding implies that in utero PFOS
exposure altered the epigenetic landscape associated with dysregulation
of fetal liver metabolism, predisposing postnatal susceptibility to
metabolic challenges
Effects of <i>In Utero</i> PFOS Exposure on Epigenetics and Metabolism in Mouse Fetal Livers
Prenatal exposure
to perfluorooctanesulfonate (PFOS)
increases
fetus’ metabolic risk; however, the investigation of the underlying
mechanism is limited. In this study, pregnant mice in the gestational
days (GD, 4.5–17.5) were exposed to PFOS (0.3 and 3 μg/g
of body weight). At GD 17.5, PFOS perturbed maternal lipid metabolism
and upregulated metabolism-regulating hepatokines (Angptl4,
Angptl8, and Selenop). Mass-spectrometry imaging and whole-genome
bisulfite sequencing revealed, respectively, selective PFOS localization
and deregulation of gene methylation in fetal livers, involved in
inflammation, glucose, and fatty acid metabolism. PCR and Western
blot analysis of lipid-laden fetal livers showed activation of AMPK
signaling, accompanied by significant increases in the expression
of glucose transporters (Glut2/4), hexose-phosphate
sensors (Retsat and ChREBP), and
the key glycolytic enzyme, pyruvate kinase (Pk) for
glucose catabolism. Additionally, PFOS modulated the expression levels
of PPARα and PPARγ downstream target genes, which simultaneously
stimulated fatty acid oxidation (Cyp4a14, Acot, and Acox) and lipogenesis (Srebp1c, Acaca, and Fasn). Using human normal hepatocyte
(MIHA) cells, the underlying mechanism of PFOS-elicited nuclear translocation
of ChREBP, associated with a fatty acid synthesizing pathway, was
revealed. Our finding implies that in utero PFOS
exposure altered the epigenetic landscape associated with dysregulation
of fetal liver metabolism, predisposing postnatal susceptibility to
metabolic challenges