Association of mitochondrial DNA haplogroup and hearing impairment with aging in Japanese general population of the Iwaki Health Promotion Project

Age-related hearing loss (ARHL) is a complex multifactorial disorder. Studies in animals, including mitochondria-mutator mice, and in human suggest that oxidative stress and mitochondrial disturbance play an important role in the pathoetiology of ARHL. Mitochondrial DNA (mtDNA) haplogroups are populations with genetically similar traits, and they have been reported to affect the mitochondrial function of oxidative phosphorylation. To gain further insights into the relationships between mitochondrial haplotypes and the susceptibility to cochlear aging, in this study, we aimed to elucidate how the differences in mtDNA haplogroups may affect ARHL development in Japanese general population. We focused on early onset ARHL, as the same mtDNA haplogroup can show either a negative or positive effect on systemic co-morbidities of ARHL that appear later in life. A total of 1167 participants of the Iwaki Health Promotion Project were surveyed in 2014, and 12 major haplotype groups (D4a, D4b, D5, G1, G2, M7a, M7b, A, B4, B5, N9, and F) were selected for the analysis. A total of 698 subjects aged 30 to 65 years were included in the statistical analysis, and the hearing loss group consisted of 112 males (40.3%) and 111 females (26.4%). Multiple logistic regression analysis showed that the male subjects belonging to haplogroup A had a significantly increased risk of hearing loss, whereas the female subjects belonging to haplogroup N9 had a significantly decreased risk of hearing loss. These results suggested that the mtDNA haplogroup may be an indicator for future risk of morbidity associated with ARHL.

Common mtDNA variations at C5178a and A249d/T6392C/G10310A decrease the risk of severe COVID-19 in a Han Chinese population from Central China

Background Mitochondria have been shown to play vital roles during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) development. Currently, it is unclear whether mitochondrial DNA (mtDNA) variants, which define mtDNA haplogroups and determine oxidative phosphorylation performance and reactive oxygen species production, are associated with COVID-19 risk. Methods A population-based case–control study was conducted to compare the distribution of mtDNA variations defining mtDNA haplogroups between healthy controls (n = 615) and COVID-19 patients (n = 536). COVID-19 patients were diagnosed based on molecular diagnostics of the viral genome by qPCR and chest X-ray or computed tomography scanning. The exclusion criteria for the healthy controls were any history of disease in the month preceding the study assessment. MtDNA variants defining mtDNA haplogroups were identified by PCR-RFLPs and HVS-I sequencing and determined based on mtDNA phylogenetic analysis using Mitomap Phylogeny. Student’s t-test was used for continuous variables, and Pearson’s chi-squared test or Fisher’s exact test was used for categorical variables. To assess the independent effect of each mtDNA variant defining mtDNA haplogroups, multivariate logistic regression analyses were performed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) with adjustments for possible confounding factors of age, sex, smoking and diseases (including cardiopulmonary diseases, diabetes, obesity and hypertension) as determined through clinical and radiographic examinations. Results Multivariate logistic regression analyses revealed that the most common investigated mtDNA variations (> 10% in the control population) at C5178a (in NADH dehydrogenase subunit 2 gene, ND2) and A249d (in the displacement loop region, D-loop)/T6392C (in cytochrome c oxidase I gene, CO1)/G10310A (in ND3) were associated with a reduced risk of severe COVID-19 (OR = 0.590, 95% CI 0.428–0.814, P = 0.001; and OR = 0.654, 95% CI 0.457–0.936, P = 0.020, respectively), while A4833G (ND2), A4715G (ND2), T3394C (ND1) and G5417A (ND2)/C16257a (D-loop)/C16261T (D-loop) were related to an increased risk of severe COVID-19 (OR = 2.336, 95% CI 1.179–4.608, P = 0.015; OR = 2.033, 95% CI 1.242–3.322, P = 0.005; OR = 3.040, 95% CI 1.522–6.061, P = 0.002; and OR = 2.890, 95% CI 1.199–6.993, P = 0.018, respectively). Conclusions This is the first study to explore the association of mtDNA variants with individual’s risk of developing severe COVID-19. Based on the case–control study, we concluded that the common mtDNA variants at C5178a and A249d/T6392C/G10310A might contribute to an individual’s resistance to developing severe COVID-19, whereas A4833G, A4715G, T3394C and G5417A/C16257a/C16261T might increase an individual’s risk of developing severe COVID-19.

PSIX-29 Study of the association of mtDNA haplogroups and Ages of 100 days in pigs

The aim of the work was to determine the mtDNA haplogroups and assess their associations with Days_100 in pigs based on sequencing the D-loop region. The research was carried out on Landrace sows (n = 123). To amplification a fragment of mtDNA D-loop conducted PCR using the following primers: F5 ‘ - TGC AAA CCA AAA CGC CAA GT-3’ and R: 3 ‘ - TTT TTG GGG TTT GGC AAG GC-5. Statistical analyzes were performed using Linear mixed model fit by REML (‘lmerModLmerTest’). The studied group of pigs had the largest number of D haplogroups, which were definitely in 66 sows (53.7%). Haplogroup E was identified in 18 sows (14.6%). Among the haplogroups of Asian origin, which include A, B and C, only genotype C was present. Statistical differences for D100 were established between Hap_C and Hap_E. The presented results indicate the influence of mtDNA haplogroups on Days_100 and pigs of hapogroup E showed the best results compared to analogs of haplogroup E. This may be due to the fact that haplotype E is of European origin, and haplotype C is of Asian origin. Breeding commercial European pigs is focused on increasing the growth rate, and this significantly reduces pig keeping costs and increases production efficiency. It should be noted that changes in growth rate are associated with more intense metabolic processes where mitochondria play a significant role. This may be reflected at the genetic level being determined by the nucleotide sequence of mtDNAs and at the haplotype level in particular. This research was funded by Ministry of Science and Higher Education of the Russian Federation (0445-2021-0008).

Mitochondrial DNA and Exercise: Implications for Health and Injuries in Sports

Recently, several studies have highlighted the tight connection between mitochondria and physical activity. Mitochondrial functions are important in high-demanding metabolic activities, such as endurance sports. Moreover, regular training positively affects metabolic health by increasing mitochondrial oxidative capacity and regulating glucose metabolism. Exercise could have multiple effects, also on the mitochondrial DNA (mtDNA) and vice versa; some studies have investigated how mtDNA polymorphisms can affect the performance of general athletes and mtDNA haplogroups seem to be related to the performance of elite endurance athletes. Along with several stimuli, including pathogens, stress, trauma, and reactive oxygen species, acute and intense exercise also seem to be responsible for mtDNA release into the cytoplasm and extracellular space, leading to the activation of the innate immune response. In addition, several sports are characterized by a higher frequency of injuries, including cranial trauma, associated with neurological consequences. However, with regular exercise, circulating cell-free mtDNA levels are kept low, perhaps promoting cf-mtDNA removal, acting as a protective factor against inflammation.

Mitochondrial DNA Haplogroup Related to the Prevalence of Helicobacter pylori

Mitochondria are essential organelles that are not only responsible for energy production but are also involved in cell metabolism, calcium homeostasis, and apoptosis. Targeting mitochondria is a key strategy for bacteria to subvert host cells’ physiology and promote infection. Helicobacter (H.) pylori targets mitochondria directly. However, mitochondrial genome (mtDNA) polymorphism (haplogroup) is not yet considered an important factor for H. pylori infection. Here, we clarified the association of mitochondrial haplogroups with H. pylori prevalence and the ability to perform damage. Seven mtDNA haplogroups were identified among 28 H. pylori-positive subjects. Haplogroup B was present at a higher frequency and haplotype D at a lower one in the H. pylori population than in that of the H. pylori-negative one. The fibroblasts carrying high-frequency haplogroup displayed a higher apoptotic rate and diminished mitochondrial respiration following H. pylori infection. mtDNA mutations were accumulated more in the H. pylori-positive population than in that of the H. pylori-negative one in old age. Among the mutations, 57% were located in RNA genes or nonsynonymous protein-coding regions in the H. pylori-positive population, while 35% were in the H. pylori-negative one. We concluded that gastric disease caused by Helicobacter virulence could be associated with haplogroups and mtDNA mutations.

MtDNA variations at C5178a and A249d decrease the risk of severe COVID-19 in a Han Chinese population from Central China

Background: Mitochondria have been shown to play vital roles during SARS-CoV-2 infection and COVID-19 development. Currently, whether mitochondrial DNA (mtDNA) variations, which define mtDNA haplogroups and determine OXPHOS performance and ROS production, are associated with COVID-19 risk is unclear. Methods: A population-based case-control study was conducted to compare the distribution of mtDNA variations defining mtDNA haplogroups between healthy controls (n = 615) and COVID-19 patients (n = 536). COVID-19 patients were diagnosed based on molecular diagnostics of the viral genome by qPCR and chest X-ray or computed tomography (CT) scanning. The exclusion criteria for the healthy controls were any history of diseases in the one-month preceding study assessment. MtDNA variations defining mtDNA haplogroups were identified by PCR-RFLPs and HVS-I sequencing and determined based upon mtDNA phylogenetic analysis using Mitomap Phylogeny. Student’s t-test was used for continuous variables, and Pearson’s chi-squared test or Fisher’s exact test was used for categorical variables. To assess the independent effect of each mtDNA variation defining mtDNA haplogroups, multivariate logistic regression analyses were performed to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) with adjustments for the possible confounding factors of age, sex, smoking and diseases (including cardiopulmonary diseases, diabetes, obesity and hypertension) determined through clinical and radiographic examinations. Results: Multivariate logistic regression analyses revealed that mtDNA variations at C5178a and A249d were associated with a reduced risk of severe COVID-19 (OR = 0.590, 95% CI = 0.428-0.814, p = 0.001; and OR = 0.654, 95% CI = 0.457-0.936, p = 0.020, respectively), while A4833G, A4715G, T3394C and G5417A/C16257a/C16261T were related to an increased risk of severe COVID-19 (OR = 2.336, 95% CI = 1.179-4.608, p = 0.015; OR = 2.033, 95% CI = 1.242-3.322, p = 0.005; OR = 3.040, 95% CI = 1.522-6.061, p = 0.002; and OR = 2.890, 95% CI = 1.199-6.993, p = 0.018, respectively). Conclusion: mtDNA variations C5178a and A249d might contribute to an individual’s resistance to developing severe COVID-19, whereas A4833G, A4715G, T3394C and G5417A/C16257a/C16261T might increase an individual’s risk of developing severe COVID-19. Trial registration: no.

Association of Mitochondrial DNA Genomic Variation With Risk of Pick Disease

ObjectiveTo determine whether stable polymorphisms that define mitochondrial haplogroups in mitochondrial DNA (mtDNA) are associated with Pick disease risk, we genotyped 52 pathologically confirmed cases of Pick disease and 910 neurologically healthy controls and performed case-control association analysis.MethodsFifty-two pathologically confirmed cases of Pick disease from Mayo Clinic Florida (n = 38) and the University of Pennsylvania (n = 14) and 910 neurologically healthy controls collected from Mayo Clinic Florida were genotyped for unique mtDNA haplogroup-defining variants. Mitochondrial haplogroups were determined, and in a case-control analysis, associations of mtDNA haplogroups with risk of Pick disease were evaluated with logistic regression models that were adjusted for age and sex.ResultsNo individual mtDNA haplogroups or superhaplogroups were significantly associated with risk of Pick disease after adjustment for multiple testing (p < 0.0021, considered significant). However, nominally significant (p < 0.05) associations toward an increased risk of Pick disease were observed for mtDNA haplogroup W (5.8% cases vs 1.6% controls, odds ratio [OR] 4.78, p = 0.020) and subhaplogroup H4 (5.8% cases vs 1.2% controls, OR 4.82, p = 0.021).ConclusionOur findings indicate that mtDNA variation is not a disease driver but may influence disease susceptibility. Ongoing genetic assessments in larger cohorts of Pick disease are currently underway.

Association of mitochondrial DNA haplogroups J and K with low response in exercise training among Finnish military conscripts

Background We have previously suggested that some of the mutations defining mitochondrial DNA (mtDNA) haplogroups J and K produce an uncoupling effect on oxidative phosphorylation and thus are detrimental for elite endurance performance. Here, the association between haplogroups J and K and physical performance was determined in a population-based cohort of 1036 Finnish military conscripts. Results Following a standard-dose training period, excellence in endurance performance was less frequent among subjects with haplogroups J or K than among subjects with non-JK haplogroups (p = 0.041), and this finding was more apparent among the best-performing subjects (p < 0.001). Conclusions These results suggest that mtDNA haplogroups are one of the genetic determinants explaining individual variability in the adaptive response to endurance training, and mtDNA haplogroups J and K are markers of low-responders in exercise training.

Genomic Steppe ancestry in skeletons from the Neolithic Single Grave Culture in Denmark

The Gjerrild burial provides the largest and best-preserved assemblage of human skeletal material presently known from the Single Grave Culture (SGC) in Denmark. For generations it has been debated among archaeologists if the appearance of this archaeological complex represents a continuation of the previous Neolithic communities, or was facilitated by incoming migrants. We sampled and analysed five skeletons from the Gjerrild cist, buried over a period of c. 300 years, 2600/2500–2200 cal BCE. Despite poor DNA preservation, we managed to sequence the genome (>1X) of one individual and the partial genomes (0.007X and 0.02X) of another two individuals. Our genetic data document a female (Gjerrild 1) and two males (Gjerrild 5 + 8), harbouring typical Neolithic K2a and HV0 mtDNA haplogroups, but also a rare basal variant of the R1b1 Y-chromosomal haplogroup. Genome-wide analyses demonstrate that these people had a significant Yamnaya-derived (i.e. steppe) ancestry component and a close genetic resemblance to the Corded Ware (and related) groups that were present in large parts of Northern and Central Europe at the time. Assuming that the Gjerrild skeletons are genetically representative of the population of the SGC in broader terms, the transition from the local Neolithic Funnel Beaker Culture (TRB) to SGC is not characterized by demographic continuity. Rather, the emergence of SGC in Denmark was part of the Late Neolithic and Early Bronze Age population expansion that swept across the European continent in the 3rd millennium BCE, resulting in various degrees of genetic replacement and admixture processes with previous Neolithic populations.