PMC

Knockdown of heat shock protein 72 (HSP72) alters primary hepatocyte fatty acid oxidation. ¹⁴C-radiolabeled fatty acid oxidation (FAO) of palmitate (100 µM) in primary hepatocytes was evaluated in the presence and absence of the carnitine palmitoyltransferase-1 (CPT-1) inhibitor etomoxir (100 µM) allowing for the evaluation of mitochondrial and nonmitochondrial mediated FAO separately and together (combined FAO). Incomplete FAO, complete FAO to CO₂, and total FAO were determined. A: incomplete, combined FAO, nonmitochondrial incomplete FAO and mitochondrial incomplete FAO in control siRNA and siHSP72- treated hepatocytes. B: complete, combined FAO to CO₂, nonmitochondrial complete FAO to CO₂, and mitochondrial complete FAO. C: total FAO (determined by adding incomplete and complete FAO to CO₂), nonmitochondrial total FAO, and mitochondrial total FAO. Values are means ± SE; n = 3. *P < 0.05, **P < 0.01, ***P < 0.001, significant differences determined by unpaired t-test between control siRNA and siHSP72 groups.

Endurance training and muscle-specific UCP3 overexpression in mice promotes muscle complete fatty acid oxidation. A) Left panel: total FAO measured in isolated mitochondria. Center panel: complete FAO (¹⁴CO₂ production), expressed as percentage of total FAO. Right panel: incomplete FAO (¹⁴C ASP production), expressed as percentage of total FAO. Training × genotype effect: P = 0.07 for percentage complete and incomplete FAO. n = 12–14. ^##P < 0.01: training effect. B) Skeletal muscle mitochondrial content. n = 16–19. ^###P < 0.0001: training effect. C) Left panel: estimated whole-muscle FAO. Right panel: estimated whole-muscle complete FAO. NoEB and EB mice were pooled. noTR, untrained; TR, trained. Training × genotype effect: P = 0.05 for whole-muscle complete FAO. n = 12–14. ^##P < 0.01, ^###P < 0.0001: training effect; ^∧P < 0.05: WT TR vs. UCP3 Tg TR. D) Total FAO measured in mouse primary myotubes. ***P < 0.0001: treatment effect. E) Complete FAO (¹⁴CO₂ production) measured in mouse primary myotubes. n = 4–5. ***P < 0.0001: treatment effect; ^∧P < 0.05: genotype effect. F) Incomplete FAO (¹⁴C-labeled ASPs) measured in mouse primary myotubes. ¹⁴C-labeled ASPs produced in medium (M) and in cell lysate (L) were measured. n = 4–5. **P < 0.01: treatment effect. Data are means ± sem.

Percent with elevated marker in the groups respectively: Panel a: FeNO; panel b: B-Eos; panel c: B-Neu. (a) Percent with elevated FeNO (≥25ppb) in the groups: Control: 17%, Asthma without FAO: 29%, Asthma with FAO: 33%, FAO without asthma: 16%, ** p < 0.001. (b) Percent with elevated B-Eos (≥300 cells/μL) in the groups: Control: 23%, Asthma without FAO: 30%, Asthma with FAO: 48%, FAO without asthma: 30%, * p < 0.05, ** p< 0.001. (c) Percent with elevated B-Neu (B-Neu ≥5100 cells/μL) in the groups: Control: 23%, Asthma without FAO: 29%, Asthma with FAO: 35%, FAO without asthma: 34%, * p < 0.05, ** p < 0.001. Abbreviations: FeNO: fraction of exhaled Nitric Oxide, B-Eos: blood eosinophils, B-Neu: blood neutrophils, FAO: fixed airflow obstruction.

Adenoviral overexpression of PGC-1α increases primary hepatocyte fatty acid oxidation (FAO). FAO rates of ¹⁴C-radiolabeled palmitate-oleate (50 μM palmitate-50 μM oleate) by primary hepatocytes were determined in the presence and absence of the carnitine palmitoyltransferase-1 (CPT-1) inhibitor etomoxir (100 μM). A: complete FAO to CO₂ was elevated in PGC-1α-overexpressing hepatocytes. B: total FAO was greater in PGC-1α-overexpressing than β-gal hepatocytes. C: FAO efficiency (percent FAO to CO₂) was greater in PGC-1α-overexpressing hepatocytes. D: complete FAO to CO₂ in the presence of etomoxir was increased in PGC-1α-overexpressing hepatocytes, and CPT-1-mediated complete FAO, as approximated by complete FAO inhibited by etomoxir, was greater in PGC-1α-overexpressing than β-gal hepatocytes. Values are means ± SE; n = 8. +P < 0.05.