The potential diagnostic use of clinical characteristics and mitochondrial DNA copy numbers of peripheral blood and ovarian tissue in polycystic ovary syndrome (PCOS) patient

Polycystic ovary syndrome (PCOS) is a complex, heterogeneous syndrome of uncertain etiology characterized by hyperandrogenemia, hyperinsulinemia, chronic anovulation, and polycystic ovaries. Recent studies showed that the abnormalities of mitochondrial metabolism are related to PCOS. We hypothesized that mtDNA copy number is an important marker that can reflect mitochondrial function. In this study, 135 PCOS patients and 57 age-matched healthy participants were studied. Mitochondrial DNA copy number in peripheral blood and PCOS ovarian tissues, and some clinical parameters were assessed. From the single factor analysis, we can find some clinical parameters are different between PCOS and healthy women and the mitochondrial DNA copy numbers in peripheral blood in PCOS women were significantly lower than in healthy women. We also found that there was no correlation between mtDNA copy numbers in peripheral blood and in ovarian tissue. After multiple logistic regressions, we identified the occurrence of PCOS was significantly positively correlated with BMI and pulse, and negatively correlated with mitochondrial DNA copy numbers in peripheral blood. We also found the decreased mtDNA copy numbers in PCOS patients are independent of these clinical parameters. We constructed the ROC curve based on these risk factors and found if they have potential to predict the patient’s outcome. In conclusion, the changes in mtDNA copy number and some clinical parameters may provide new ideas for PCOS diagnosis. More studies are necessary for further validation of their use in PCOS diagnosis.

A Comprehensive RNA Study to Identify circRNA and miRNA Biomarkers for Docetaxel Resistance in Breast Cancer

To investigate the relationship between non-coding RNAs [especially circular RNAs (circRNAs)] and docetaxel resistance in breast cancer, and to find potential predictive biomarkers for taxane-containing therapies, we have performed transcriptome and microRNA (miRNA) sequencing for two established docetaxel-resistant breast cancer (DRBC) cell lines and their docetaxel-sensitive parental cell lines. Our analyses revealed differences between circRNA signatures in the docetaxel-resistant and -sensitive breast cancer cells, and discovered circRNAs generated by multidrug-resistance genes in taxane-resistant cancer cells. In DRBC cells, circABCB1 was identified and validated as a circRNA that is strongly up-regulated, whereas circEPHA3.1 and circEPHA3.2 are strongly down-regulated. Furthermore, we investigated the potential functions of these circRNAs by bioinformatics analysis, and miRNA analysis was performed to uncover potential interactions between circRNAs and miRNAs. Our data showed that circABCB1, circEPHA3.1 and circEPHA3.2 may sponge up eight significantly differentially expressed miRNAs that are associated with chemotherapy and contribute to docetaxel resistance via the PI3K-Akt and AGE-RAGE signaling pathways. We also integrated differential expression data of mRNA, long non-coding RNA, circRNA, and miRNA to gain a global profile of multi-level RNA changes in DRBC cells, and compared them with changes in DNA copy numbers in the same cell lines. We found that Chromosome 7 q21.12-q21.2 was a common region dominated by multi-level RNA overexpression and DNA amplification, indicating that overexpression of the RNA molecules transcribed from this region may result from DNA amplification during stepwise exposure to docetaxel. These findings may help to further our understanding of the mechanisms underlying docetaxel resistance in breast cancer.

Distinct Epigenetic Reprogramming, Mitochondrial Patterns, Cellular Morphology and Cytotoxicity after Bee Venom Treatment

Background: Bee venom is a promising agent for use in cancer treatment due to its selective cytotoxic potential for cancer cells through apoptotic pathways. However, there is no evidence for changes in epigenome and mitochondrial DNA copy numbers after bee venom application. The purpose of this study was to determine the impact of bee venom on cytosine modifications and mitochondrial DNA copy number variation. Methods: A broad range of methods was applied to elucidate the impact of bee venom on neoplastic cells. These included MTT assay for detection of cytotoxicity, immunostaining of cytosine modifications and mitochondria, assessment of cellular morphology by flow cytometry and quantification of mitochondrial DNA copy numbers using QPCR. Results: Bee venom-induced cell death was selective for cancer cells, where it triggered a response characterised by alteration of cytosine modification. In contrast, normal cells were more resistant to DNA modifications. Furthermore, application of the venom resulted in variation of mitochondrial membrane permeability and mitochondrial DNA copy numbers, together with alterations in cell morphology manifesting as a reduced affected cell size. Conclusion: The study findings suggest that bee venom can be used as a selective DNA (de)methylating agent in cancer. Various agents (such as Decitabine and 5-azacytidine) have been synthesized and developed for use in cancer treatment, and a range of syntheses, and preparation and application methods have been described for these patented drugs. However, to the best of our knowledge, no previous research has investigated the use of bee venom or any component thereof for epigenetic therapy in cancer cells.

Sperm mitochondrial DNA copy numbers in normal and abnormal semen analysis: a systematic review and meta-analysis.

Background: Normal mature sperm have a considerably reduced number of mitochondria which provide the energy required for progressive sperm motility. Literature suggests that disorders of sperm motility may be linked to abnormal sperm mitochondrial number and function. Objectives: To summarise the evidence from literature regarding the association of mitochondrial DNA copy numbers and semen quality with a particular emphasis on the spermatozoa motility. Search strategy: Standard methodology recommended by Cochrane. Selection criteria: All published primary research reporting on differences in mitochondrial DNA copy numbers between the sperm of males with a normal and abnormal semen analysis. Data collection and analysis: Using standard methodology recommended by Cochrane we pooled results using a random effects model and the findings were reported as a standardised mean difference. Main results: We included 10 trials. The primary outcome was sperm mitochondrial DNA copy numbers. A meta-analysis including five studies showed significantly higher mitochondrial DNA copy numbers in abnormal semen analysis as compared to normal semen analysis(SMD 1.08, 95% CI 0.74-1.43). Three other studies not included in the meta-analysis showed a significant negative correlation between mitochondrial DNA copy numbers and semen parameters. The quality of evidence was assessed as good to very good in 60% of studies. Conclusions: Our review demonstrates significantly higher mitochondrial DNA in human sperm cells of men with abnormal semen analysis in comparison to men with normal semen analysis. PROSPERO registration: CRD42019118841 Funding None received

Origin, Regulation, and Fitness Effect of Chromosomal Rearrangements in the Yeast Saccharomyces cerevisiae

Chromosomal rearrangements comprise unbalanced structural variations resulting in gain or loss of DNA copy numbers, as well as balanced events including translocation and inversion that are copy number neutral, both of which contribute to phenotypic evolution in organisms. The exquisite genetic assay and gene editing tools available for the model organism Saccharomyces cerevisiae facilitate deep exploration of the mechanisms underlying chromosomal rearrangements. We discuss here the pathways and influential factors of chromosomal rearrangements in S. cerevisiae. Several methods have been developed to generate on-demand chromosomal rearrangements and map the breakpoints of rearrangement events. Finally, we highlight the contributions of chromosomal rearrangements to drive phenotypic evolution in various S. cerevisiae strains. Given the evolutionary conservation of DNA replication and recombination in organisms, the knowledge gathered in the small genome of yeast can be extended to the genomes of higher eukaryotes.

Mitochondrial dysfunction in sepsis is associated with diminished intramitochondrial TFAM despite its increased cellular expression

Sepsis is characterized by a dysregulated immune response, metabolic derangements and bioenergetic failure. These alterations are closely associated with a profound and persisting mitochondrial dysfunction. This however occurs despite increased expression of the nuclear-encoded transcription factor A (TFAM) that normally supports mitochondrial biogenesis and functional recovery. Since this paradox may relate to an altered intracellular distribution of TFAM in sepsis, we tested the hypothesis that enhanced extramitochondrial TFAM expression does not translate into increased intramitochondrial TFAM abundance. Accordingly, we prospectively analyzed PBMCs both from septic patients (n = 10) and lipopolysaccharide stimulated PBMCs from healthy volunteers (n = 20). Extramitochondrial TFAM protein expression in sepsis patients was 1.8-fold greater compared to controls (p = 0.001), whereas intramitochondrial TFAM abundance was approximate 80% less (p < 0.001). This was accompanied by lower mitochondrial DNA copy numbers (p < 0.001), mtND1 expression (p < 0.001) and cellular ATP content (p < 0.001) in sepsis patients. These findings were mirrored in lipopolysaccharide stimulated PBMCs taken from healthy volunteers. Furthermore, TFAM-TFB2M protein interaction within the human mitochondrial core transcription initiation complex, was 74% lower in septic patients (p < 0.001). In conclusion, our findings, which demonstrate a diminished mitochondrial TFAM abundance in sepsis and endotoxemia, may help to explain the paradox of lacking bioenergetic recovery despite enhanced TFAM expression.