SIRT1 activation alleviates brain microvascular endothelial dysfunction in peroxisomal disorders

Area of Science:

• Neuroscience
• Biochemistry
• Genetics

Background:

• Peroxisomal disorders are genetic metabolic diseases impacting fatty acid oxidation and often causing early-onset neurodegeneration.
• X-linked adrenoleukodystrophy, a common peroxisomal disorder due to ABCD1 gene mutations, involves brain microvascular endothelial dysfunction and monocyte permeability.
• Sirtuin 1 (SIRT1) plays a role in cellular regulation and is implicated in various disease processes.

Purpose of the Study:

• To investigate the role of sirtuin 1 (SIRT1) dysregulation in human brain microvascular endothelial cells (HBMECs) under peroxisomal dysfunction.
• To determine if resveratrol can ameliorate the molecular and functional changes in HBMECs caused by peroxisomal dysfunction.

Main Methods:

• Silencing of ATP binding cassette subfamily D member 1 (ABCD1) or hydroxysteroid 17-beta dehydrogenase 4 in HBMECs to induce peroxisomal dysfunction.
• Assessing changes in adhesion molecules and tight-junction proteins.
• Evaluating monocyte adhesion to HBMECs.
• Treating HBMECs with resveratrol and analyzing its effects on signaling pathways like nuclear factor-kappa B (NF-κB) and Krüppel-like factor 4 (KLF4).

Main Results:

• Peroxisomal dysfunction, induced by ABCD1 or HSD17B4 gene silencing, led to SIRT1 dysregulation in HBMECs.
• This dysregulation resulted in altered expression of adhesion molecules and tight-junction proteins, increasing monocyte adhesion.
• Resveratrol treatment enhanced SIRT1 function, attenuating these detrimental molecular and functional changes in HBMECs.
• These effects were mediated by the modulation of NF-κB and KLF4 signaling pathways.

Conclusions:

• SIRT1 dysregulation is a key mediator of brain microvascular endothelial dysfunction in peroxisomal disorders.
• Targeting SIRT1 with compounds like resveratrol shows potential for therapeutic intervention in these neurodegenerative conditions.
• Modulation of NF-κB and KLF4 pathways by SIRT1 is crucial for maintaining endothelial barrier integrity.