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Parkinsonism & Related Disorders Jun 2024Growing evidence has shown that mitochondrial dysfunction is part of the pathogenesis of Parkinson's disease (PD). However, the role of mitochondrial DNA (mtDNA)... (Review)
Review
BACKGROUND
Growing evidence has shown that mitochondrial dysfunction is part of the pathogenesis of Parkinson's disease (PD). However, the role of mitochondrial DNA (mtDNA) variants on PD onset is unclear.
OBJECTIVES
The present study aims to evaluate the effect of mtDNA variants and haplogroups on risk of developing PD.
METHODS
Systematic review and meta-analysis of studies investigating associations between PD and mtDNA variants and haplogroups.
RESULTS
A total of 33 studies were eligible from 957 screened studies. Among 13,640 people with PD and 22,588 control individuals, the association with PD was consistently explored in 13 mtDNA variants in 10 genes and 19 macrohaplogroups. Four mtDNA variants were associated with PD: m.4336C (odds ratio [OR] = 2.99; 95 % confidence interval [CI] = 1.79-5.02), m.7028T (OR = 0.80; 95 % CI = 0.70-0.91), m.10398G (OR = 0.92; 95 % CI = 0.85-0.98), and m.13368A (OR = 0.74; 95 % CI = 0.56-0.98). Four mtDNA macrohaplogroups were associated with PD: R (OR = 2.25; 95 % CI = 1.92-2.65), F (OR = 1.18; 95 % CI = 1.01-1.38), H (OR = 1.12; 95 % CI = 1.06-1.18), and B (OR = 0.77; 95 % CI = 0.65-0.92).
CONCLUSIONS
Despite most studies may be underpowered by the underrepresentation of people without dominant European- and Asian-ancestry, low use of next-generation sequencing for genotyping and small sample sizes, the identification of mtDNA variants and macrohaplogroups associated with PD strengthens the link between the disease and mitochondrial dysfunction and mtDNA genomic instability.
PubMed: 38917640
DOI: 10.1016/j.parkreldis.2024.107044 -
Mitochondrion Jun 2024Mitochondrial dysfunction contributes to pathological conditions like ischemia-reperfusion (IR) injury. To address the lack of effective therapeutic interventions for IR... (Review)
Review
Mitochondrial dysfunction contributes to pathological conditions like ischemia-reperfusion (IR) injury. To address the lack of effective therapeutic interventions for IR injury and potential knowledge gaps in the current literature, we systematically reviewed 3800 experimental studies across 5 databases and identified 20 mitochondrial genes impacting IR injury in various organs. Notably, CyPD, Nrf2, and GPX4 are well-studied genes consistently influencing IR injury outcomes. Emerging genes like ALDH2, BNIP3, and OPA1 are supported by human genetic evidence, thereby warranting further investigation. Findings of this review can inform future research directions and inspire therapeutic advancements.
PubMed: 38848983
DOI: 10.1016/j.mito.2024.101908 -
Cell Journal May 2024The relationship between oxidative stress (OS), insulin resistance (IR), and polycystic ovary syndrome (PCOS) is an important medical issue in human reproduction. Some...
OBJECTIVE
The relationship between oxidative stress (OS), insulin resistance (IR), and polycystic ovary syndrome (PCOS) is an important medical issue in human reproduction. Some of the oxidative phosphorylation (OXPHOS) genes have been previously studied in granulosa and muscle cells of PCOS patients. Cumulus cells (CCs) remain close to the oocyte even after ovulation. This research has been designed to compare the expression of OXPHOS genes in CCs of PCOS, with or without insulin resistance.
MATERIALS AND METHODS
In this experimental study, patients were included in PCOS insulin-resistant, PCOS insulinsensitive (IS), and control (fertile women with male infertility history) groups. The expression of and was studied by real-time polymerase chain reaction (PCR), and normalization was performed considering and as reference genes. One-way ANOVA and Tukey test were used for data analysis.
RESULTS
The results showed that the expression of and was significantly higher in the IR group than IS and control groups (P<0.01). showed the highest expression in the IS group, which was significantly different from other groups (P<0.01). The other genes of interest, except , were observed with the most transcriptional levels in the IS group, although there was no significant difference for those genes.
CONCLUSION
Altered expression of genes involved in mitochondrial function compared to the control group in CCs of both IR and IS categories of the PCOS patients suggests that alteration in OXPHOS genes can contribute to the pathophysiology of PCOS.
PubMed: 38736407
DOI: 10.22074/cellj.2024.2006763.1357 -
Molecular Diagnosis & Therapy Jul 2024HtrA1, HtrA2, HtrA3 and HtrA4 appear to be involved in the development of pathologies such as cancer. This systematic review reports the results of a literature search...
PURPOSE
HtrA1, HtrA2, HtrA3 and HtrA4 appear to be involved in the development of pathologies such as cancer. This systematic review reports the results of a literature search performed to compare the expression of HtrA family genes and proteins in cancer versus non-cancer tissues and cell lines, assess relationships between HtrA expression and cancer clinical features in cancer, and analyse the molecular mechanism, by which HtrA family affects cancer.
METHODS
The literature search was conducted according to the PRISMA statement among four databases (PubMed, Web of Science, Embase and Scopus).
RESULTS
A total of 38 articles met the inclusion criteria and involved the expression of HtrA family members and concerned the effect of HtrA expression on cancer and metastasis development or on the factor that influences it. Additionally, 31 reports were retrieved manually. Most articles highlighted that HtrA1 and HtrA3 exhibited tumour suppressor activity, while HtrA2 was associated with tumour growth and metastasis. There were too few studies to clearly define the role of the HtrA4 protease in tumours.
CONCLUSION
Although the expression of serine proteases of the HtrA family was dependent on tumour type, stage and the presence of metastases, most articles indicated that HtrA1 and HtrA3 expression in tumours was downregulated compared with healthy tissue or cell lines. The expression of HtrA2 was completely study dependent. The limited number of studies on HtrA4 expression made it impossible to draw conclusions about differences in expression between healthy and tumour tissue. The conclusions drawn from the study suggest that HtrA1 and HtrA3 act as tumour suppressors.
Topics: Humans; Neoplasms; High-Temperature Requirement A Serine Peptidase 1; Serine Endopeptidases; High-Temperature Requirement A Serine Peptidase 2; Gene Expression Regulation, Neoplastic; Mitochondrial Proteins
PubMed: 38717523
DOI: 10.1007/s40291-024-00712-2 -
Neurobiology of Disease Jul 2024Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting 1 in 36 children and is associated with physiological abnormalities, most notably mitochondrial... (Meta-Analysis)
Meta-Analysis
Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting 1 in 36 children and is associated with physiological abnormalities, most notably mitochondrial dysfunction, at least in a subset of individuals. This systematic review and meta-analysis discovered 204 relevant articles which evaluated biomarkers of mitochondrial dysfunction in ASD individuals. Significant elevations (all p < 0.01) in the prevalence of lactate (17%), pyruvate (41%), alanine (15%) and creatine kinase (9%) were found in ASD. Individuals with ASD had significant differences (all p < 0.01) with moderate to large effect sizes (Cohen's d' ≥ 0.6) compared to controls in mean pyruvate, lactate-to-pyruvate ratio, ATP, and creatine kinase. Some studies found abnormal TCA cycle metabolites associated with ASD. Thirteen controlled studies reported mitochondrial DNA (mtDNA) deletions or variations in the ASD group in blood, peripheral blood mononuclear cells, lymphocytes, leucocytes, granulocytes, and brain. Meta-analyses discovered significant differences (p < 0.01) in copy number of mtDNA overall and in ND1, ND4 and CytB genes. Four studies linked specific mtDNA haplogroups to ASD. A series of studies found a subgroup of ASD with elevated mitochondrial respiration which was associated with increased sensitivity of the mitochondria to physiological stressors and neurodevelopmental regression. Lactate, pyruvate, lactate-to-pyruvate ratio, carnitine, and acyl-carnitines were associated with clinical features such as delays in language, social interaction, cognition, motor skills, and with repetitive behaviors and gastrointestinal symptoms, although not all studies found an association. Lactate, carnitine, acyl-carnitines, ATP, CoQ10, as well as mtDNA variants, heteroplasmy, haplogroups and copy number were associated with ASD severity. Variability was found across biomarker studies primarily due to differences in collection and processing techniques as well as the intrinsic heterogeneity of the ASD population. Several studies reported alterations in mitochondrial metabolism in mothers of children with ASD and in neonates who develop ASD. Treatments targeting mitochondria, particularly carnitine and ubiquinol, appear beneficial in ASD. The link between mitochondrial dysfunction in ASD and common physiological abnormalities in individuals with ASD including gastrointestinal disorders, oxidative stress, and immune dysfunction is outlined. Several subtypes of mitochondrial dysfunction in ASD are discussed, including one related to neurodevelopmental regression, another related to alterations in microbiome metabolites, and another related to elevations in acyl-carnitines. Mechanisms linking abnormal mitochondrial function with alterations in prenatal brain development and postnatal brain function are outlined. Given the multisystem complexity of some individuals with ASD, this review presents evidence for the mitochondria being central to ASD by contributing to abnormalities in brain development, cognition, and comorbidities such as immune and gastrointestinal dysfunction as well as neurodevelopmental regression. A diagnostic approach to identify mitochondrial dysfunction in ASD is outlined. From this evidence, it is clear that many individuals with ASD have alterations in mitochondrial function which may need to be addressed in order to achieve optimal clinical outcomes. The fact that alterations in mitochondrial metabolism may be found during pregnancy and early in the life of individuals who eventually develop ASD provides promise for early life predictive biomarkers of ASD. Further studies may improve the understanding of the role of the mitochondria in ASD by better defining subgroups and understanding the molecular mechanisms driving some of the unique changes found in mitochondrial function in those with ASD.
Topics: Humans; Autism Spectrum Disorder; Biomarkers; DNA, Mitochondrial; Mitochondria; Mitochondrial Diseases
PubMed: 38703861
DOI: 10.1016/j.nbd.2024.106520 -
CNS Neuroscience & Therapeutics Mar 2024Mitochondrial complex III (CIII) deficiency is an autosomal recessive disease characterized by symptoms such as ataxia, cognitive dysfunction, and spastic paraplegia....
BACKGROUND
Mitochondrial complex III (CIII) deficiency is an autosomal recessive disease characterized by symptoms such as ataxia, cognitive dysfunction, and spastic paraplegia. Multiple genes are associated with complex III defects. Among them, the mutation of TTC19 is a rare subtype.
METHODS
We screened a Chinese boy with weakness of limbs and his non-consanguineous parents by whole exome sequencing and targeted sequencing.
RESULTS
We report a Chinese boy diagnosed with mitochondrial complex III defect type 2 carrying a homozygous variant (c.719-732del, p.Leu240Serfs*17) of the TTC19 gene. According to the genotype analysis of his family members, this is an autosomal recessive inheritance. We provide his clinical manifestation.
CONCLUSIONS
A new type of TTC19 mutation (c.719-732del, p.Leu240Serfs*17) was found, which enriched the TTC19 gene mutation spectrum and provided new data for elucidating the pathogenesis of CIII-deficient diseases.
Topics: Male; Humans; Electron Transport Complex III; Membrane Proteins; Mutation; Peripheral Nervous System Diseases; Movement Disorders; Pedigree; Mitochondrial Diseases
PubMed: 37927170
DOI: 10.1111/cns.14425 -
European Child & Adolescent Psychiatry Jun 2024The global prevalence of attention-deficit/hyperactivity disorder (ADHD) is estimated to be between 6% and 7% in children worldwide. The pathophysiology of this... (Review)
Review
The global prevalence of attention-deficit/hyperactivity disorder (ADHD) is estimated to be between 6% and 7% in children worldwide. The pathophysiology of this heterogeneous neurodevelopmental disorder remains unknown. Mitochondrial dysfunction has been proposed as a possible contributing factor to the etiology of ADHD. There is limited literature available to help our understanding of this hypothesis, and thus we conducted a systematic review of the number and quality of studies pertaining to mitochondrial genetic alterations in ADHD. A systematic search was conducted in the relevant databases Medline (PubMed) and Embase up to March 2021. Inclusion criteria included randomized control trials, cross-sectional studies, and case-control studies. This search resulted in a total of 507 articles that emerged from the search criteria. Of these results, 10 primary research articles were selected for in depth review based on the inclusion and exclusion criteria. These studies all reported on mitochondrial genetic variation in ADHD cases such as increased copy number, single-nucleotide polymorphisms, and haplogroup associations. This initial review of the experimental literature suggests mitochondrial genetic variation, in both the mitochondrial DNA and nuclear-encoded mitochondrial genes, may indeed contribute to ADHD pathophysiology. The studies reviewed here provide promising evidence for future research to further examine the mitochondrial genetics contributing to ADHD pathophysiology. We suggest that expansion of investigations into mitochondrial mechanisms may have potential to inform new treatment options for ADHD.
Topics: Humans; Attention Deficit Disorder with Hyperactivity; DNA, Mitochondrial; Genetic Variation; Mitochondria; Child; Polymorphism, Single Nucleotide
PubMed: 35796884
DOI: 10.1007/s00787-022-02030-6