Dataset Information

Altered Peroxisome Proliferator-Activated Receptor Alpha Signaling in Variably Diseased Peripheral Arterial Segments.

ABSTRACT:

Objective

Peripheral atherosclerosis that accumulates in the extracranial carotid and lower extremity arteries can lead to significant morbidity and mortality. However, atherosclerotic disease progression is often not homogenous and is accelerated by diabetes. We previously observed increased phospholipid content in minimally (Min)-diseased arterial segments compared to maximally (Max)-diseased segments. Since Peroxisome Proliferator-Activated Receptor alpha (PPARα) is a key regulator of lipid metabolism, we hypothesized that it may have differential expression and signaling in Min vs. Max-diseased peripheral arterial segments.

Methods

Eighteen patients who underwent carotid endarterectomy (CEA), and 34 patients who underwent major lower extremity amputation were prospectively enrolled into a vascular tissue biobank. Min and Max-diseased segments were obtained in real-time from CEA plaque and amputated lower extremity arterial segments. mRNA and protein were isolated from specimens and the relative expression of ppara, and its downstream genes Acyl-CoA Oxidase 1 (acox1) and Carnitine Palmitoyltransferase 1A (cpt1a) were also evaluated. We evaluated gene expression and protein content relative to atherosclerotic disease severity and clinical diabetes status. Gene expression was also evaluated relative to Hemoglobin A1c and serum lipid profiles.

Results

In CEA segments of patients with diabetes, we observed significantly higher ppara and acox1 gene expression (p < 0.01 and p < 0.001 respectively), and higher PPARα protein content (p < 0.05). Hemoglobin A1c significantly correlated with expression of ppara (R² = 0.66, p < 0.001), acox1 (R² = 0.31, p < 0.05), and cpt1a (R² = 0.4, p < 0.05). There was no significant difference in gene expression between Min vs. Max-diseased CEA plaque segments. Conversely, in lower extremity arterial segments of patients with diabetes, we observed significantly lower ppara, acox1, and cpt1a expression (p < 0.05, p < 0.001, and p < 0.0001 respectively). Interestingly, CPT1A content was lower in arterial segments of patients with diabetes (p < 0.05). Hemoglobin A1c and HDL-cholesterol had negative correlations with ppara (R² = 0.44, p < 0.05; R² = 0.42, p < 0.05; respectively).

Conclusion

This study demonstrates the significant differential expression of ppara and its immediate downstream genes in human carotid and lower extremity arteries relative to disease severity and diabetes. These findings highlight that mechanisms that influence atheroprogression in the carotid and lower extremities peripheral arteries are not homogenous and can be impacted by patient diabetes status and serum cholesterol profiles. Further elucidating these differential molecular mechanisms can help improve targeted therapy of atherosclerosis in different peripheral arterial beds.

SUBMITTER: Engel C

PROVIDER: S-EPMC9248745 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background: Peripheral blood mononuclear cells (PBMCs) are relatively easily obtainable cells in humans. Gene expression profiles of PBMCs have been shown to reflect the pathological and physiological state of a person. Recently, we showed that the nuclear receptor peroxisome proliferator-activated receptor alpha (PPARα) has a functional role in human PBMCs during fasting. However, the extent of the role of PPARα in human PBMCs remains unclear. In this study, we therefore performed gene expression profiling of PBMCs incubated with the specific PPARα ligand WY14,643. Results: Incubation of PBMCs with WY14,643 for 12 hours resulted in a differential expression of 1,373 of the 13,080 genes expressed in the PBMCs. Gene expression profiles showed a clear individual response to PPARα activation between six healthy human blood donors, which was not the result of the nutritional status of the donors. Pathway analysis showed that genes in fatty acid metabolism, primarily in β-oxidation were up-regulated upon activation of PPARα with WY14,643, and genes in several amino acid metabolism pathways were down-regulated. Conclusions: This study shows that PPARα in human PBMCs regulates fatty acid and amino acid metabolism. In addition, PBMC gene expression profiles show individual responses to WY14,643 activation. We show that PBMCs are a suitable model to study changes in PPARα activation in healthy humans. Keywords: metabolic state analysis PBMCs from six healthy Caucasian male blood donors, aged between 30 and 48 yr, were isolated directly after arrival of the buffy coat (max. 8 hours after donation) by Ficol-paque Plus density gradient centrifugation (Amersham Biosciences, Roosendaal, the Netherlands). PBMCs were incubated in RPMI1640 medium with 2 mmol/L L-glutamine, 10% fetal bovine serum and antibiotics (penicillin and streptomycin) in the presence of 5% CO2 at 37°C. at 1.0 x 106 cells per ml with either WY14,643 (50 μM) or vehicle (DMSO, 0.1%) for 12 hours. Total RNA from PBMCs was labeled using a one-cycle cDNA labeling kit (Affymetrix Inc, Santa Clara, CA) and hybridized to Affymetrix Human whole genome U133 plus 2.0 arrays (Affymetrix). Sample labeling, hybridization to chips and image scanning was performed according to the manufacturer’s GeneChip Expression Analysis Technical Manual (Affymetrix).