Dataset Information

Rats with a Human Mutation of NFU1 Develop Pulmonary Hypertension.

ABSTRACT: NFU1 is a mitochondrial protein that is involved in the biosynthesis of iron-sulfur clusters, and its genetic modification is associated with disorders of mitochondrial energy metabolism. Patients with autosomal-recessive inheritance of the NFU1 mutation G208C have reduced activity of the respiratory chain Complex II and decreased levels of lipoic-acid-dependent enzymes, and develop pulmonary arterial hypertension (PAH) in ∼70% of cases. We investigated whether rats with a human mutation in NFU1 are also predisposed to PAH development. A point mutation in rat NFU1^G206C (human G208C) was introduced through CRISPR/Cas9 genome editing. Hemodynamic data, tissue samples, and fresh mitochondria were collected and analyzed. NFU1^G206C rats showed increased right ventricular pressure, right ventricular hypertrophy, and high levels of pulmonary artery remodeling. Computed tomography and angiography of the pulmonary vasculature indicated severe angioobliterative changes in NFU1^G206C rats. Importantly, the penetrance of the PAH phenotype was found to be more prevalent in females than in males, replicating the established sex difference among patients with PAH. Male and female homozygote rats exhibited decreased expression and activity of mitochondrial Complex II, and markedly decreased pyruvate dehydrogenase activity and lipoate binding. The limited development of PAH in males correlated with the preserved levels of oligomeric NFU1, increased expression of ISCU (an alternative branch of the iron-sulfur assembly system), and increased complex IV activity. Thus, the male sex has additional plasticity to overcome the iron-sulfur cluster deficiency. Our work describes a novel, humanized rat model of NFU1 deficiency that showed mitochondrial dysfunction similar to that observed in patients and developed PAH with the same sex dimorphism.

SUBMITTER: Niihori M

PROVIDER: S-EPMC6993542 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:ObjectiveNFU1 is a mitochondrial iron-sulfur scaffold protein, involved in iron-sulfur assembly and transfer to complex II and LAS (lipoic acid synthase). Patients with the point mutation NFU1G208C and CRISPR/CAS9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9)-generated rats develop mitochondrial dysfunction leading to pulmonary arterial hypertension. However, the mechanistic understanding of pulmonary vascular proliferation due to a single mutation in NFU1 remains unresolved. Approach and Results: Quantitative proteomics of isolated mitochondria showed the entire phenotypic transformation of NFU1G206C rats with a disturbed mitochondrial proteomic landscape, involving significant changes in the expression of 208 mitochondrial proteins. The NFU1 mutation deranged the expression pattern of electron transport proteins, resulting in a significant decrease in mitochondrial respiration. Reduced reliance on mitochondrial respiration amplified glycolysis in pulmonary artery smooth muscle cell (PASMC) and activated GPD (glycerol-3-phosphate dehydrogenase), linking glycolysis to oxidative phosphorylation and lipid metabolism. Decreased PDH (pyruvate dehydrogenase) activity due to the lipoic acid shortage is compensated by increased fatty acid metabolism and oxidation. PASMC became dependent on extracellular fatty acid sources due to upregulated transporters such as CD36 (cluster of differentiation 36) and CPT (carnitine palmitoyltransferase)-1. Finally, the NFU1 mutation produced a dysregulated antioxidant system in the mitochondria, leading to increased reactive oxygen species levels. PASMC from NFU1 rats showed apoptosis resistance, increased anaplerosis, and attained a highly proliferative phenotype. Attenuation of mitochondrial reactive oxygen species by mitochondrial-targeted antioxidant significantly decreased PASMC proliferation.ConclusionsThe alteration in iron-sulfur metabolism completely transforms the proteomic landscape of the mitochondria, leading toward metabolic plasticity and redistribution of energy sources to the acquisition of a proliferative phenotype by the PASMC.

Project description:NFU1 is an iron-sulfur (Fe-S) scaffold protein, involved in Fe-S assembly and transfer to a range of mitochondrial metalloproteins. Patients with the NFU1G208C mutation develop pulmonary arterial hypertension (PAH) with 70% penetrance. Rats with NFU1G206C homozygous mutation demonstrated the PAH phenotype showing increased pulmonary vasculature remodeling, right ventricular (RV) hypertrophy, and RV pressure. In the present study, we discovered phenotypic metabolic changes in pulmonary arterial smooth muscle cells (PASMC) from NFU1G206C homozygous mutant rats associated with alterations in the mitochondrial proteome. Quantitative analysis of the mitochondrial proteome showed significant changes in the abundance of 208 proteins involved in various metabolic and antioxidant functions in response to the NFU1 mutation. Our data indicates that the NFU1G206C homozygous mutant rats have decreased expression of complex I and II, which are known to depend on iron-sulfur clusters, and increased expression of complexes III to V, accompanied with a significant decrease in mitochondrial function, pyruvate dehydrogenase (PDH) activity and amplified glycolysis and anabolism in PASMC. The NFU1 mutation produced a dysregulated antioxidant system in the mitochondria which leads to increased levels of reactive oxygen species. Due to alterations in apoptosis regulating proteins, the NFU1G206C cells were found to exhibit high proliferation rates and resistance to apoptosis as compared with the wild type (WT). Finally, the NFU1G206C mitochondrial proteome showed significant abundance changes in proteins that regulate fatty acid (FA) metabolism and exhibited increased FA oxidation compared to WT, suggesting increased FA oxidation compensates for the decreased PDH activity. In conclusion, our data indicates that the NFU1G206C mutation induces a metabolic shift in the PASMC, which results in a hyper-proliferative and apoptosis resistant phenotype and presents a novel cellular model to study PAH.

Dataset Information

Rats with a Human Mutation of NFU1 Develop Pulmonary Hypertension.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets