bims-curels 2024-03-10 papers

Issue of 2024–03–10
four papers selected by
Cure Mito Foundation

Mitochondrion. 2024 Mar 02. pii: S1567-7249(24)00016-3. [Epub ahead of print] 101858

Identification of a novel MT-ND3 variant and restoring mitochondrial function by allotopic expression of MT-ND3 gene.

Nurun Nahar Borna, Yoshihito Kishita, Masaru Shimura, Kei Murayama, Akira Ohtake, Yasushi Okazaki.

Mitochondrial diseases are caused by nuclear, or mitochondrial DNA (mtDNA) variants and related co-factors. Here, we report a novel m.10197G > C variant in MT-ND3 in a patient, and two other patients with m.10191 T > C. MT-ND3 variants are known to cause Leigh syndrome or mitochondrial complex I deficiency. We performed the functional analyses of the novel m.10197G > C variant that significantly lowered MT-ND3 protein levels, causing complex I assembly and activity deficiency, and reduction of ATP synthesis. We adapted a previously described re-engineering technique of delivering mitochondrial genes into mitochondria through codon optimization for nuclear expression and translation by cytoplasmic ribosomes to rescue defects arising from the MT-ND3 variants. We constructed mitochondrial targeting sequences along with the codon-optimized MT-ND3 and imported them into the mitochondria. To achieve the goal, we imported codon-optimized MT-ND3 into mitochondria in three patients with m.10197G > C and m.10191 T > C missense variants in the MT-ND3. Nuclear expression of the MT-ND3 gene partially restored protein levels, complex I deficiency, and significant improvement of ATP production indicating a functional rescue of the mutant phenotype. The codon-optimized nuclear expression of mitochondrial protein and import inside the mitochondria can supplement the requirements for ATP in energy-deficient mitochondrial disease patients.

Keywords: Allotopic expression; Codon-optimization; Leigh Syndrome; MT-ND3; Mitochondrial DNA

DOI: https://doi.org/10.1016/j.mito.2024.101858

Stem Cell Res. 2024 Mar 05. pii: S1873-5061(24)00077-1. [Epub ahead of print]76 103379

Generation of a human induced pluripotent stem cell line NTUHi004-A from a patient with Leigh syndrome harboring a homozygous missense mutation c.836 T > G (p.Met279Arg) in NDUFAF5 gene.

Chih-Hsin Ou-Yang, Pin-Shiuan Chen, Chin-Hsien Lin.

Leigh syndrome is a rare autosomal recessive disorder showcasing a diverse range of neurological symptoms. Classical Leigh syndrome is associated with mitochondrial complex I deficiency, primarily resulting from biallelic mutations in the NDUFAF5 gene, encoding the NADH:ubiquinone oxidoreductase complex assembly factor 5. Using the Sendai virus delivery system, we generated an induced pluripotent stem cell line from peripheral blood mononuclear cells of a 47-years-old female patient who carried a homozygous NDUFAF5 c.836 T > G (p.Met279Arg) mutation. This cellular model serves as a tool for investigating the underlying pathogenic mechanisms and for the development of potential treatments for Leigh syndrome.

DOI: https://doi.org/10.1016/j.scr.2024.103379

Sci Rep. 2024 Mar 08. 14(1): 5702

Mitochondrial DNA mutations in Korean patients with Leber's hereditary optic neuropathy.

Hee Kyung Yang, Moon-Woo Seong, Jeong-Min Hwang.

In order to explore the spectrum of mitochondrial DNA (mtDNA) mutations in Korean patients with Leber's hereditary optic neuropathy (LHON), we investigated the spectrum of mtDNA mutations in 145 Korean probands confirmed with the diagnosis of LHON. Total genomic DNA was isolated from the peripheral blood leukocytes of the patients with suspected LHON, and mtDNA mutations were identified by direct sequencing. Analysis of mtDNA mutations revealed seven primary LHON mutations including the nucleotide positions (nps) 11778A (101 probands, 69.2%), 14484C (31 probands, 21.2%), 3460A (5 probands, 3.4%), and G3635A, G3733A, C4171A, and G13051A mutations in one proband each. In addition, two provisional mtDNA mutations at nps T3472C, and G13259A were each found in one proband, respectively. Another provisional mtDNA mutation at np T3394C was found in two probands. In conclusion, the spectrum of mtDNA mutations in Korean patients with LHON may differ from other ethnicities, which is characterized by high prevalence of 11778A and 14484C mutations, and a low prevalence of the 3460A mutation.

Keywords: Koreans; Leber’s hereditary optic neuropathy; Mitochondrial DNA mutation; Spectrum

DOI: https://doi.org/10.1038/s41598-024-56215-x

Indian J Otolaryngol Head Neck Surg. 2024 Feb;76(1): 1014-1017

Auditory Brainstem Response in a Child with Mitochondrial Disorder-Leigh Syndrome.

P S Pooja, R Greeshma, Emin K Joy, Shreyank P Swamy.

The mitochondrial disorder-Leigh syndrome is a neurodegenerative disorder often manifested with brainstem abnormalities. The case report highlights the auditory brainstem response in a child with medical findings suggestive of Leigh syndrome. The case report also emphasizes the importance of ruling out any underlying neural pathology before making a clinical impression in children with developmental delays.

Keywords: Auditory brainstem response; Auditory maturation delay; Brainstem dysfunction; Global developmental delay; Leigh syndrome; Mitochondrial disorder

DOI: https://doi.org/10.1007/s12070-023-03971-3