Potentiel thérapeutique de l'inhibition d'HDAC6 en hypertension artérielle pulmonaire

Authors: Chabot, Sophie
Advisor: Provencher, Steeve
Abstract: RATIONALE: Pulmonary arterial hypertension (PAH) is a vascular remodeling disease with limited therapeutic options. Although exposed to stressful conditions, pulmonary artery (PA) smooth muscle cells (PASMCs) exhibit a pro-proliferative and anti-apoptotic phenotype. HDAC6 is a cytoplasmic histone deacetylase implicated in the regulation of multiple pro-survival mechanisms and overexpressed in response to stress in cancer cells. Due to the similarities between cancer and PAH, we hypothesized that HDAC6 expression is increased in PAH-PASMCs to face stress, allowing them to survive and proliferate, thus contributing to vascular remodeling in PAH. OBJECTIVE: Using genetically modified mice and pharmacological approaches, we aimed to demonstrate that HDAC6 inhibition is a promising strategy to improve PAH. METHODS AND RESULTS: HDAC6 is significantly up-regulated in lungs, distal PAs and isolated PASMCs from PAH patients and animal models. Molecular and pharmacological inhibition of HDAC6 reduces PAH-PASMC proliferation (Ki67 labeling) and resistance to apoptosis (Annexin V assay) in vitro sparing control cells. Mechanistically, we demonstrate that HDAC6 deacetylates Ku70, blocking the translocation of Bax to the mitochondria and preventing apoptosis. In vivo inhibition of HDAC6 (Tubastatin A) significantly improves established PAH in two experimental models (Sugen/hypoxia and monocrotaline) and can be safely given in combination with currently approved PAH therapies. Finally, Hdac6 K.O mice have significantly lower right ventricle systolic pressure in response to 3 weeks of chronic-hypoxia compared to wild-type mice. CONCLUSION: We showed for the first time that HDAC6 is implicated in PAH development and represents a new promising therapeutic target to improve PAH.
Document Type: Mémoire de maîtrise
Issue Date: 2017
Open Access Date: 24 April 2018
Permalink: http://hdl.handle.net/20.500.11794/27840
Grantor: Université Laval
Collection:Thèses et mémoires

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