Mitochondrial Deoxyribonucleic Acid Research Articles

Evaluation of unmodifiedhuman cell-derived extracellular vesicle mitochondrial deoxyribonucleic acid-based biodistribution in rodents.

Recently, extracellular vesicles (EVs) have been developed as therapeutic targets for various diseases. Biodistribution is crucial for EVs intended for therapeutic purposes because it can determine the degree of on- and off-target effects. This study aimed to explore techniques to evaluate the biodistribution of unmodified EVs. We devised a novel quantitative polymerase chain reaction (qPCR)-based assay to detect unmodified EVs by targeting mitochondrial deoxyribonucleic acid (mtDNA), a constituent of EVs. We focused on specific mtDNA regions that exhibited homologous variations distinct from their rodent mtDNA counterparts to establish this analytical approach. Herein, we successfully designed primers and probes targeting human and rodent mtDNA sequences and developed a highly specific and sensitive qPCR method. Furthermore, the quantification range of EVs isolated from various cells differed based on the manufacturer and cell source. IRDye 800CW-labelled Expi293F EV mimetics were administered to the animals via the tail vein to compare the imaging test and mtDNA-qPCR results. The results obtained from imaging tests and mtDNA-qPCR to investigate EV biodistribution patterns revealed differences. The results revealed that our newly developed method effectively determined the biodistribution of unmodified EVs with high sensitivity and reproducibility.

Association of eating habits with mitochondrial DNA copy number in eveningness chronotypes: origin research

Objective: To determine the relationship between eating habits and mitochondrial deoxyribonucleic acid copy number in adult cases of eveningness chronotypes. Method: The cross-sectional, analytical study was conducted from September 2022 to June 2023 at the Physiology Department of the Islamic International Medical College, Rawalpindi, in collaboration with the Genetic Resource Centre, Rawalpindi, Pakistan, and comprised adult subjects who were assessed using the Morningness-Eveningness Questionnaire. The participants' eating habits were assessed using the Healthy Eating Assessment Questionnaire, and on they were divided into those with healthy eating habits in group A and those with unhealthy eating habits in group B. Deoxyribonucleic acid was extracted using the Chelex method, the mitochondrial deoxyribonucleic acid copy number of all participants was quantified using quantitative polymerase chain reaction. Data was analysed using SPSS 27. Results: Of the 80 subjects, 30(37.5%) were males and 50(62.5%) were females. The overall mean age was 24.27±6.91 years (range: 18-45 years). There were 40(50%) subjects in each group. The mean mitochondrial deoxyribonucleic acid copy number in group A was 2.74±0.14 compared to 2.26±0.25 in group B (p<0.001). Conclusion: Subjects with healthy eating habits exhibited higher mitochondrial deoxyribonucleic acid copy numbers, indicating reduced damage to mitochondrial deoxyribonucleic acid. Key Words: Mitochondria, Mitochondrial DNA, Eating habits, Chronotype.

Role of mitochondrial DNA level in epidural-related maternal fever: a single-centre, observational, pilot study

IntroductionEpidural analgesia has been associated with intrapartum maternal fever development. Epidural-related maternal fever (ERMF) is believed to be based on a non-infectious inflammatory reaction. Circulating cell-free mitochondrial deoxyribonucleic acid (mtDNA) is one of the possible triggers of sterile inflammatory processes; however, a connection has not been investigated so far. Therefore, this study aimed to investigate cell-free mtDNA alterations in women in labour with ERMF in comparison with non-febrile women.Material and methodsA total of 60 women in labour were assessed for maternal temperature every 4 h and blood samples were obtained at the beginning and after delivery. Depending on the analgesia and the development of fever (axillary temperature ≥ 37.5 °C), the women were allocated either to the group of no epidural analgesia (n = 17), to epidural analgesia no fever (n = 34) or to ERMF (n = 9). Circulating cell-free mtDNA was analysed in the maternal plasma for the primary outcome whereas secondary outcomes include the evaluation of inflammatory cytokine release, as well as placental inflammatory signs.ResultsOf the women with epidural analgesia, 20% (n = 9) developed ERMF and demonstrated a decrease of circulating mtDNA levels during labour (p = 0.04), but a trend towards higher free nuclear DNA. Furthermore, women with maternal pyrexia showed a 1.5 fold increased level of Interleukin-6 during labour. A correlation was found between premature rupture of membranes and ERMF.ConclusionsThe pilot trial revealed an evident obstetric anaesthesia phenomenon of maternal fever due to epidural analgesia in 20% of women in labour, demonstrating counterregulated free mtDNA and nDNA. Further work is urgently required to understand the connections between the ERMF occurrence and circulating cell-free mtDNA as a potential source of sterile inflammation.Trial registrationNCT0405223 on clinicaltrials.gov (registered on 25/07/2019).

Mitochondrial Deoxyribonucleic Acid Copy Number Elevation As a Predictor for Extended Survival and Favorable Outcomes in High-Grade Brain Tumor Patients: A Malaysian Study

Mitochondrial Deoxyribonucleic Acid Copy Number Elevation As a Predictor for Extended Survival and Favorable Outcomes in High-Grade Brain Tumor Patients: A Malaysian Study

ASK1/ p38 axis inhibition blocks the release of mitochondrial "danger signals" from hepatocytes and suppresses progression to cirrhosis and liver cancer.

Apoptosis Signal-regulating Kinase 1 (ASK1) is activated by various pathological stimuli and induces cell apoptosis through downstream p38 activation. We studied the effect of pharmacological ASK1 inhibition on cirrhosis and its sequelae using comprehensive preclinical in vivo and in vitro systems. Short-term (4-6wk) and long-term (24-44wk) ASK1 inhibition using small molecule GS-444217 was tested in thioacetamide-induced and BALB/c. Mdr2-/- murine models of cirrhosis and HCC, and in vitro using primary hepatocyte cell death assays. Short-term GS-444217 therapy in both models strongly reduced phosphorylated p38, hepatocyte death, and fibrosis by up to 50%. Profibrogenic release of mitochondrial DAMP mitochondrial deoxyribonucleic acid from dying hepatocytes was blocked by ASK1 or p38 inhibition. Long-term (24wk) therapy in BALBc.Mdr2 - / - model resulted in a moderate 25% reduction in bridging fibrosis, but not in net collagen deposition. Despite this, the development of cirrhosis was effectively prevented, with strongly reduced p21 + hepatocyte staining (by 72%), serum ammonia levels (by 46%), and portal pressure (average 6.07 vs. 8.53mmHg in controls). Extended ASK1 inhibition for 44wk in aged BALB/c. Mdr2-/- mice resulted in markedly reduced tumor number and size by ~50% compared to the control group. ASK1 inhibition suppresses the profibrogenic release of mitochondrial deoxyribonucleic acid from dying hepatocytes in a p38-dependent manner and protects from liver fibrosis. Long-term ASK1 targeting resulted in diminished net antifibrotic effect, but the progression to liver cirrhosis and cancer in BALBc/ Mdr2- / - mice was effectively inhibited. These data support the clinical evaluation of ASK1 inhibitors in fibrotic liver diseases.

Mitochondrial DNA drives neuroinflammation through the cGAS-IFN signaling pathway in the spinal cord of neuropathic pain mice.

Neuroinflammation is pivotal in the development of neuropathic pain (NeP). While mitochondrial deoxyribonucleic acid (mtDNA) and cyclic GMP-AMP synthase (cGAS) are recognized for inducing inflammation in various neurological disorders, their involvement in NeP remains ambiguous. In this study, we examined: (1) the changes in mtDNA and cGAS in mice with NeP induced by chronic constriction injury (CCI) of the sciatic nerve, whether mtDNA triggers inflammation via the cGAS signaling; (2) the effects of RU.521, a cGAS antagonist, on CCI-induced nociception (allodynia and hyperalgesia) and relative inflammatory protein expression; (3) the activation of microglia and the cGAS-IFN pathway mediated by mtDNA in BV2 cell; (4) the effect of RU.521 on mtDNA-induced inflammatory response in BV2 cells. Results revealed reduced mtDNA levels in the sciatic nerve but increased levels in the spinal cord of CCI mice, along with elevated cGAS expression and inflammatory factors. RU.521 alleviated nociceptive behaviors in CCI mice, possibly by normalizing cGAS levels and suppressing inflammation. Neuron-derived mtDNA provoked cellular activation and upregulated cGAS signaling in BV2 cells. Additionally, RU.521 and DNase I effectively inhibited cGAS-induced inflammation. These findings underscore the critical role of mtDNA accumulation and mtDNA-mediated cGAS signaling in NeP development after peripheral nerve injury.

Mitonuclear epistasis involving TP63 and haplogroup Uk: Risk of rapid progression of knee OA in patients from the OAI

To investigate genetic interactions between mitochondrial deoxyribonucleic acid (mtDNA) haplogroups and nuclear single nucleotide polymorphisms (nSNPs) to analyze their impact on the development of the rapid progression of knee osteoarthritis (OA). A total of 1095 subjects from the Osteoarthritis Initiative, with a follow-up time of at least 48-months, were included. Appropriate statistical approaches were performed, including generalized estimating equations adjusting for age, gender, body mass index, contralateral knee OA, Western Ontario and McMaster Universities Osteoarthritis Index pain, previous injury in target knee and the presence of the mtDNA variant m.16519C. Additional genomic data consisted in the genotyping of Caucasian mtDNA haplogroups and eight nSNPs previously associated with the risk of knee OA in robust genome-wide association studies. The simultaneous presence of the G allele of rs12107036 at TP63 and the haplogroup Uk significantly increases the risk of a rapid progression of knee OA (odds ratio=1.670; 95% confidence interval [CI]: 1.031-2.706; adjusted p-value=0.027). The assessment of the population attributable fraction showed that the highest proportion of rapid progressors was under the simultaneous presence of the G allele of rs12107036 and the haplogroup Uk (23.4%) (95%CI: 7.89-38.9; p-value<0.05). The area under the curve of the cross-validation model (0.730) was very similar to the obtained for the predictive model (0.735). A nomogram was constructed to help clinicians to perform clinical trials or epidemiologic studies. This study demonstrates the existence of a mitonuclear epistasis in OA, providing new mechanisms by which nuclear and mitochondrial variation influence the susceptibility to develop different OA phenotypes.

Determining lineages between individuals with high-density mitochondrial and Y-chromosomal single-nucleotide polymorphisms.

Genetic genealogy has been more frequently used in forensic investigations in identifying criminals. However, the current genetic genealogy applications usually do not consider lineage markers (including both Y and mitochondrial deoxyribonucleic acid (DNA)), which is probably because not all distant relatives share the same lineage markers. In addition, there is no study to show how to use lineage markers and what methods or thresholds should be applied in genetic genealogy. In this study, we developed a method to quickly determine if two single-nucleotide polymorphism (SNP) profiles are from the same paternal or material lineages by using a mismatch frequency of the SNPs in Y-chromosomal or mitochondrial DNA. For both Y and mitochondrial SNPs, profile pairs from the same or different lineages can be decided with high accuracies (i.e., 0.380% or 0.157% error rates with Y and mitochondrial DNA, respectively). With kinship coefficient filtering based on autosomal SNPs, the accuracies of determining maternal and paternal lineage can be further improved (i.e., 0.120% or 0.057% error rates with Y and mitochondrial DNA, respectively, using a threshold of kinship coefficient >0). This study shows that lineage markers can be very powerful tools with high accuracies to determine lineages, which could help solve cases and reduce costs for genetic genealogy investigations.

Deoxyguanosine kinase deficiency and recurrent spontaneous pneumothorax: a case report

BackgroundDeoxyguanosine kinase deficiency is mainly manifested by hepatic and neurological damage, hence it belongs to the hepatocerebral form of mitochondrial deoxyribonucleic acid depletion syndrome. The association between deoxyguanosine kinase deficiency and recurrent spontaneous pneumothorax has not currently been reported.Case presentationA 12-year-old Russian boy with deoxyguanosine kinase deficiency, a recipient of a liver transplant with amyotrophy secondary to his mitochondriopathy, presented with recurrent spontaneous bilateral pneumothorax refractory to drainage and surgery.ConclusionTo our knowledge, this is the first documented case of deoxyguanosine kinase deficiency associated with recurrent spontaneous pneumothorax, which could be considered a late complication of deoxyguanosine kinase deficiency. At this point, this is only an association and further studies and research need to be performed to help confirm the pathogenesis of this association.

Mitochondrion-NLRP3 inflammasome activation in macrophages: A novel mechanism of the anti-inflammatory effect of Notopterygium in rheumatoid arthritis treatment

ObjectiveThe mechanism by which Notopterygium (NE) regulates the nucleotide‐binding, oligomerization domain (NOD)‐like receptor family and pyrin domain-containing 3 (NLRP3) inflammasome to treat rheumatoid arthritis (RA) was investigated to reveal the scientific implications of NE in RA treatment. MethodsAdjuvant arthritis (AA) rats were replicated. After NE intervention, the anti-inflammatory efficacy of NE in vivo was determined. The mechanism of NE in RA treatment was predicted by network pharmacology, and the key target for further experiments was found through the analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG). The effect of NE on the NLRP3 inflammasome in AA rats was verified. Furthermore, with the induction of inflammation in RAW264.7 cells by lipopolysaccharide (LPS), several techniques, such as Griess assay, enzyme linked immunosorbent assays, electron microscopy, and fluorescence probe technology, were used to investigate the anti-inflammatory and related mechanisms of NE in RA treatment. ResultsNE could inhibit inflammation in AA rats. KEGG results showed that NLRP3 participated in the top three pathways of NE in RA treatment. Through Western blotting and immunofluorescence assays, this study demonstrated that NE can regulate NLRP3, pro-Caspase-1, Caspase-1, and CD11b in the ankle joint of AA rats. NE may significantly reduce the LPS-induced inflammatory response of RAW264.7 cells by alleviating mitochondrial damage, reducing the number of mitochondrial deoxyribonucleic Acid and mitochondrial reactive oxygen species, inhibiting NLRP3 inflammasome activation. ConclusionThe anti-inflammatory and antirheumatic effect of NE may involve regulating NLRP3 inflammasome activation through mitochondria. NLRP3 is probably the key target molecule of NE in the treatment of RA.

Maternal ancestry and lineages diversity of the Santander population from Colombia.

Santander, located in the Andean region of Colombia, is one of the 32 departments of the country. Its population was shaped by intercontinental admixture between autochthonous native Americans, European settlers, and African slaves. To establish forensic databases of haplotype frequencies, the evaluation of population substructure is crucial to capture the genetic diversity in admixed populations. Total control region mitochondrial deoxyribonucleic acid haplotypes were determined for 204 individuals born in the seven provinces across the department. The maternal native heritage is highly preserved in Santander genetic background, with 90% of the haplotypes belonging to haplogroups inside A2, B4, C1, and D. Most native lineages are found broadly across the American continent, while some sub-branches are concentrated in Central America and north South America. Subtle European (6%) and African (4%) input was detected. In pairwise comparisons between provinces, relatively high FST values were found in some cases, although not statistically significant. Nonetheless, when provinces were grouped according to the principal component analysis results, significant differences were detected between groups. The database on mitochondrial deoxyribonucleic acid control region haplotype frequencies established here can be further used for populational and forensic purposes.

Genetic study of two populations of Sitophilus oryzae following two types of maize: Yellow maize and yellow-white maize from two different localities in Senegal

The objective of this study is to determine the genetic diversity and structure, demographic evolution and phylogenetic relationships of Sitophilus oryzae (S. oryzae) in two types of maize: yellow maize and yellow-white maize from two localities in Senegal. Thus, individuals of S. oryzae from each locality are used, after sampling and massive rearing. The Cyt-B gene of the mitochondrial DNA (deoxyribonucleic acid) was targeted and sequenced. The obtained sequences are corrected, aligned and exploited. Overall, haplotypic diversity (Hd) is non-significantly high (0.895 ±0.058) while nucleotide diversity (Nd) is significantly low (0.016±0.003), even when populations are considered separately; the Salemata population (Hd=0.949 ±0.051, Nd= 0.015±0.003) is more diverse with P-values≤0.05. Results confirmed by polymorphism with a high number of singletons and haplotypes. This genetic variability can be explained by the fact that we had two different substrates but phenotypically very similar. The parameters of genetic differentiation, demographic and phylogenetic evolution revealed a weak genetic structuring of S. oryzae, populations in demographic expansion and poorly defined parental relationships between populations. This study provided further insight into the genetic characteristics of Sitophilus.

Premature ovarian insufficiency: a review on the role of oxidative stress and the application of antioxidants.

Normal levels of reactive oxygen species (ROS) play an important role in regulating follicular growth, angiogenesis and sex hormone synthesis in ovarian tissue. When the balance between ROS and antioxidants is disrupted, however, it can cause serious consequences of oxidative stress (OS), and the quantity and quality of oocytes will decline. Therefore, this review discusses the interrelationship between OS and premature ovarian insufficiency (POI), the potential mechanisms and the methods by which antioxidants can improve POI through controlling the level of OS. We found that OS can mediate changes in genetic materials, signal pathways, transcription factors and ovarian microenvironment, resulting in abnormal apoptosis of ovarian granulosa cells (GCs) and abnormal meiosis as well as decreased mitochondrial Deoxyribonucleic Acid(mtDNA) and other changes, thus accelerating the process of ovarian aging. However, antioxidants, mesenchymal stem cells (MSCs), biological enzymes and other antioxidants can delay the disease process of POI by reducing the ROS level in vivo.

Mitochondrial Deoxyribonucleic Acid (mtDNA), Maternal Inheritance, and Their Role in the Development of Cancers: A Scoping Review.

Mitochondrial DNA (mtDNA) is a small, circular, double-stranded DNA inherited from the mother during fertilization. Evolutionary evidence supported by the endosymbiotic theory identifies mitochondria as an organelle that could have descended from prokaryotes. This may be the reason for the independent function and inheritance pattern shown by mtDNA. The unstable nature of mtDNA due to the lack of protective histones, and effective repair systems make it more vulnerable to mutations. The mtDNA and its mutations could be maternally inherited thereby predisposing the offspringto various cancers like breast and ovarian cancers among others.Although mitochondriaare considered heteroplasmic wherein variations among the multiple mtDNA genomes are noticed, mothers can have mitochondrial populations that are homoplasmic for a given mitochondrial mutation.Homoplasmic mitochondrial mutations may be transmitted to all maternal offspring. However, due to the complex interplay between the mitochondrial and nuclear genomes, it is often difficult to predict disease outcomes, even with homoplasmic mitochondrial populations.Heteroplasmic mtDNA mutations can be maternally inherited, but the proportion of mutated alleles differs markedly between offspring within one generation. This led to the genetic bottleneck hypothesis, explaining the rapid changes in allele frequency witnessed during the transmission of mtDNA from one generation to the next. Although a physical reduction in mtDNA has been demonstrated in several species, a comprehensive understanding of the molecular mechanisms is yet to be demonstrated. Despite initially thought to be limited to the germline, there is evidence that blockages exist in different cell types during development, perhaps explaining why different tissues in the same organism contain different levels of mutated mtDNA. In this review, we comprehensively discuss the potential mechanisms through which mtDNA undergoes mutationsand the maternal mode of transmissionthat contributes to the development of tumors, especially breast and ovarian cancers.

Application of Next Generation Sequencing (NGS) technology in forensic science: A review

One of the most important achievements of Next Generation Sequencing (NGS) is to produce millions of sequences reads in a short period of time, and to produce large sequences of deoxyribonucleic acid (DNA) in fragments of any size. Libraries can be generated from whole genomes or any DNA or RNA region of interest without the need to know its sequence beforehand. In the forensic field, one of the main problems is the limited amount of sample available, as well as its degraded state samples. Next-generation sequencing (NGS) technology, with its high-throughput capacity and low cost, has developed rapidly in recent years and become an important analytical tool for many genomics researchers. New opportunities in the research domain of the forensic studies emerge by using the power of next generation sequencing technology, which can be applied to simultaneously analyzing multiple loci of forensic interest in different genetic materials. Furthermore, next-generation sequencing (NGS) technology can also have potential applications in many other aspects of forensic science such as achieving the simultaneous analysis of the standard autosomal DNA (STRs and SNPs), deoxyribonucleic acid (DNA) database construction, ancestry and phenotypic inferences, monozygotic twin studies, body fluid and species identification, forensic animal, plant and microbiological analyses, mitochondrial DNA, microbiological analysis, epigenetics analysis, MicroRNA analysis, animal and plant DNA analysis and X and Y chromosomal markers. In this study, we review the application of next generation sequencing (NGS) technology in the field of forensic science with the aim of providing a reference for future forensic studies and practice.

Aging and oocyte competence: A molecular cell perspective.

Follicular microenvironment is paramount in the acquisition of oocyte competence, which is dependent on two interconnected and interdependent processes: nuclear and cytoplasmic maturation. Extensive research conducted in human and model systems has provided evidence that those processes are disturbed with female aging. In fact, advanced maternal age (AMA) is associated with a lower chance of pregnancy and live birth, explained by the age-related decline in oocyte quality/competence. This decline has largely been attributed to mitochondria, essential for oocyte maturation, fertilization, and embryo development; with mitochondrial dysfunction leading to oxidative stress, responsible for nuclear and mitochondrial damage, suboptimal intracellular energy levels, calcium disturbance, and meiotic spindle alterations, that may result in oocyte aneuploidy. Nuclear-related mechanisms that justify increased oocyte aneuploidy include deoxyribonucleic acid (DNA) damage, loss of chromosomal cohesion, spindle assembly checkpoint dysfunction, meiotic recombination errors, and telomere attrition. On the other hand, age-dependent cytoplasmic maturation failure is related to mitochondrial dysfunction, altered mitochondrial biogenesis, altered mitochondrial morphology, distribution, activity, and dynamics, dysmorphic smooth endoplasmic reticulum and calcium disturbance, and alterations in the cytoskeleton. Furthermore, reproductive somatic cells also experience the effects of aging, including mitochondrial dysfunction and DNA damage, compromising the crosstalk between granulosa/cumulus cells and oocytes, also affected by a loss of gap junctions. Old oocytes seem therefore to mature in an altered microenvironment, with changes in metabolites, ribonucleic acid (RNA), proteins, and lipids. Overall, understanding the mechanisms implicated in the loss of oocyte quality will allow the establishment of emerging biomarkers and potential therapeutic anti-aging strategies. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology.

Ferulic Acid: Signaling Pathways in Aging.

The need for clinical remedies to the multiple age-related deficiencies in skin function brought on by extrinsic and intrinsic causes is increased by these demographic changes. Reactive oxygen species (ROS), mitochondrial deoxyribonucleic acid (mtDNA) mutations, telomere shortening, as well as other factors, contribute to the aging of the skin. In this overview, the issue of human skin aging is introduced, along with several pathways and the protective effects of ferulic acid in light of current patents. The complex antioxidant effect of ferulic acid depends on the "sweeping" away of free radicals as well as the suppression of the synthesis of ROS or nitrogen. Furthermore, Cu (II) or Fe protonated metal ions are chelated by this acid (II). Ferulic acid is a free radical scavenger as well as an enzyme inhibitor, increasing the activity of enzymes that scavenge free radicals while decreasing the activity of enzymes that speed up the creation of free radicals. AMPK signalling, which can regulate cellular homeostasis, stress tolerance, cell survival and proliferation, cell death, and autophagy, has recently been linked to aging and lifespan. Therefore, Caenorhabditis elegans (C. elegans) and rodents had longer life-spans due to specific AMPK activation. By inhibiting the TGF-β/Smad signalling pathway, UV irradiation can reduce the production of procollagen. Glycation changes the skin's physical characteristics, making it less elastic and stiffer. . Excessive free radicals simultaneously trigger the nuclear factor kappa B (NF- κB) signalling pathway, increasing TNF levels and matrix metalloproteinase production (MMPs).

The Acute Effects of Exercise on Saliva-Derived Regional Mitochondrial DNA from Trained Runners

ABSTRACT Introduction/Purpose Research has identified two regions within mitochondrial deoxyribonucleic acid (mtDNA), which seem to be more (major arc; mtMAJ) and less (minor arc; mtMIN) prone to oxidation and mtDNA lesion formation. Oxidation of mtDNA base pairs can result in reduced copy number and has been linked to chronic diseases. Interestingly, exercise can also induce acute copy number reductions; however, in a healthy population, there seems to be a restorative effect (i.e., gaining mtDNA copy numbers) that occurs within a couple of hours to days after exercise. Few have investigated these regional mtDNA changes in trained runners (&gt;90th fitness percentile). Typical mtDNA procedures are invasive and inconvenient, requiring muscle biopsies, and/or blood draws; therefore, a simpler, less invasive method of specimen collection is appealing. The purpose of this study was to examine how salivary-derived molecular (mtMAJ and mtMIN), hormonal (cortisol), and oxidative (8-hydroxy-2′-deoxyguanosine (8-OHdG)) markers change after acute exercise. Methods Trained runners (n = 7; 52 ± 12 miles·wk−1 run in the past year; 28.8 ± 3.3 yr old; height, 1.76 ± 0.07 m; weight, 67.9 ± 11.3 kg; maximum oxygen consumption, 62.4 ± 5.7 mL·kg−1·min−1) completed a 60-min treadmill run at 70% peak oxygen consumption. Saliva samples were collected before exercise, 30 min after exercise (30Post), and 6 h after exercise (6hPost) and analyzed for changes in regional mtDNA via real-time quantitative polymerase chain reaction and stress (cortisol and 8-OHdG) markers using competitive enzyme-linked immunosorbent assays. Results mtMIN copy number decreased 30Post (−44.5%, P = 0.04) and 6hPost (−45.3% P = 0.03), but mtMAJ copy numbers were unchanged after exercise (P = 0.44). Neither of the stress-related saliva biomarkers changed after exercise (cortisol, P = 0.13; 8-OHdG, P = 0.77). Conclusions Saliva-derived DNA findings point to mtMIN, supposedly the more stable of the two regions, as a greater contributor to copy number reductions within our cohort of trained runners. These results contribute to the understanding of aerobic exercise’s influence over saliva-derived, regional mtDNA dynamics.

Multi-omics identifies large mitoribosomal subunit instability caused by pathogenic MRPL39 variants as a cause of pediatric onset mitochondrial disease.

MRPL39 encodes one of 52 proteins comprising the large subunit of the mitochondrial ribosome (mitoribosome). In conjunction with 30 proteins in the small subunit, the mitoribosome synthesizes the 13 subunits of the mitochondrial oxidative phosphorylation (OXPHOS) system encoded by mitochondrial Deoxyribonucleic acid (DNA). We used multi-omics and gene matching to identify three unrelated individuals with biallelic variants in MRPL39 presenting with multisystem diseases with severity ranging from lethal, infantile-onset (Leigh syndrome spectrum) to milder with survival into adulthood. Clinical exome sequencing of known disease genes failed to diagnose these patients; however quantitative proteomics identified a specific decrease in the abundance of large but not small mitoribosomal subunits in fibroblasts from the two patients with severe phenotype. Re-analysis of exome sequencing led to the identification of candidate single heterozygous variants in mitoribosomal genes MRPL39 (both patients) and MRPL15. Genome sequencing identified a shared deep intronic MRPL39 variant predicted to generate a cryptic exon, with transcriptomics and targeted studies providing further functional evidence for causation. The patient with the milder disease was homozygous for a missense variant identified through trio exome sequencing. Our study highlights the utility of quantitative proteomics in detecting protein signatures and in characterizing gene-disease associations in exome-unsolved patients. We describe Relative Complex Abundance analysis of proteomics data, a sensitive method that can identify defects in OXPHOS disorders to a similar or greater sensitivity to the traditional enzymology. Relative Complex Abundance has potential utility for functional validation or prioritization in many hundreds of inherited rare diseases where protein complex assembly is disrupted.

BaoShenTongLuo formula protects against podocyte injury by regulating AMPK-mediated mitochondrial biogenesis in diabetic kidney disease

BackgroundMitochondrial dysfunction is considered to be an important contributor in podocyte injury under diabetic conditions. The BaoShenTongLuo (BSTL) formula has been shown to reduce podocyte damage and postpone the progression of diabetic kidney disease (DKD). The potential mechanisms underlying the effects of BSTL, however, have yet to be elucidated. In this study, we aimed to investigate whether the effects of BSTL are related to the regulation of mitochondrial biogenesis via the adenosine monophosphate-activated protein kinase (AMPK) pathway.MethodsHigh-Performance Liquid Chromatography Electrospray Ionization Mass Spectrometer (HPLC–ESI–MS) analysis was performed to investigate the characteristics of pure compounds in BSTL. db/db mice and mouse podocyte clone-5 (MPC5) cells were exposed to high glucose (HG) to induce DKD and podocyte damage. Body weight, random blood glucose, urinary albumin/creatinine ratio (UACR), indicators of renal function and renal histological lesions were measured. Markers of podocyte injury, mitochondrial morphology, mitochondrial deoxyribonucleic acid (mtDNA) content, mitochondrial respiratory chain complexes activities, reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) levels were assessed. Protein expressions of AMPK, peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), transcription factor A (TFAM), mitochondrial fusion protein 2 (MFN2) and dynamin-related protein 1 (DRP1) were also detected. MPC5 cells were transfected with AMPKα small interfering RNA (AMPKα siRNA) to determine the underlying mechanisms of BSTL improvement of mitochondrial function under diabetic conditions.ResultsIn vivo, treatment with BSTL reduced the UACR levels, reversed the histopathological changes in renal tissues, and alleviated the podocyte injury observed in db/db mice. After BSTL treatment, the decreased mtDNA content and mitochondrial respiratory chain complex I, III, and IV activities were significantly improved, and these effects were accompanied by maintenance of the protein expression of p-AMPKαT172, PGC-1α, TFAM and MFN2. The in vitro experiments also showed that BSTL reduced podocyte apoptosis, suppressed excessive cellular ROS production, and reversed the decreased in MMP that were observed under HG conditions. More importantly, the effects of BSTL in enhancing mitochondrial biogenesis and reducing podocyte apoptosis were inhibited in AMPKα siRNA-treated podocytes.ConclusionBSTL plays a crucial role in protecting against podocyte injury by regulating the AMPK-mediated mitochondrial biogenesis in DKD.