Mitochondrial Genetic Variation in Iranian Infertile Men with Varicocele

Comparative efficiency of differential diagnostic methods for the identification of BRAF V600E gene mutation in papillary thyroid cancer (Review)

V-Raf murine sarcoma viral oncogene homolog B1 (BRAF) encodes a serine-threonine kinase. The V600E point mutation in the BRAF gene is the most common mutation, predominantly occurring in melanoma, and colorectal, thyroid and non-small cell lung cancer. Particularly in the context of thyroid cancer research, it is routinely employed as a molecular biomarker to assist in diagnosing and predicting the prognosis of papillary thyroid cancer (PTC), and to formulate targeted therapeutic strategies. Currently, several methods are utilized in clinical settings to detect BRAF V600E mutations in patients with PTC. However, the sensitivity and specificity of various detection techniques vary significantly, resulting in diverse detection outcomes. The present review highlights the advantages and disadvantages of the methods currently employed in medical practice, with the aim of guiding clinicians and researchers in selecting the most suitable detection approach for its high sensitivity, reproducibility and potential to develop targeted therapeutic regimens for patients with BRAF gene mutation-associated PTC.

Varicocele associated male infertility: cellular and molecular perspectives of pathophysiology

BACKGROUND

Varicocele is a common risk factor associated with reduced male fertility potential. The current understanding of varicocele pathophysiology does not completely explain the clinical manifestation of infertility. The present treatment options such as antioxidant supplementation and varicocelectomy only helps ∼35% of men to achieve spontaneous pregnancy.

OBJECTIVE

This review aims to summarize the available knowledge on cellular and molecular alterations implicated to varicocele associated male infertility and also highlights the new knowledge generated by 'Omics' technologies.

MATERIALS AND METHODS

PubMed, MEDLINE, Cochrane and Google Scholar databases are searched using different combinations of keywords (varicocele, infertile/fertile men with varicocele, cellular changes, molecular mechanisms, proteome, epigenome, transcriptome and metabolome). A total of 229 relevant human and animal studies published till 2021 were included in this review.

RESULTS

Current understanding advocates oxidative stress (OS) as a major contributory factor to the varicocele associated male infertility. Excessive OS causes alteration in testicular microenvironment and sperm DNA fragmentation which further contributes to infertility. Molecular and omics studies have identified several promising biomarkers such as AAMP, SPINT1, MKI67 (genetic markers), sperm quality and function related protein markers, global sperm DNA methylation level (epigenetic marker), Hspa2, Protamine, Gadd7, Dynlt1 and Beclin1 (mRNA markers), PRDX2, HSPA, APOA2, YKL40 (seminal protein markers), total choline and PHGDH (metabolic markers).

DISCUSSION

Mature spermatozoa harbours a plethora of molecular information in form of proteome, epigenome and transcriptome; which could provide very important clues regarding pathophysiology of varicocele associated infertility. Recent molecular and omics studies in infertile men with varicocele have identified several promising biomarkers. Upon further validation with larger and well-defined studies, some of these biomarkers could aid in varicocele management.

CONCLUSION

The present evidences suggest inclusion of OS and sperm DNA fragmentation tests could be useful to the diagnostic workup for men with varicocele. Furthermore, including precise molecular markers may assist in diagnostics and prognostics of varicocele associated male infertility. This article is protected by copyright. All rights reserved.

Assessment of the Role of Nuclear ENDOG Gene and mtDNA Variations on Paternal Mitochondrial Elimination (PME) in Infertile Men: An Experimental Study

In humans and most animals, maternal inheritance of mitochondria and mitochondrial DNA (mtDNA) is considered as an universal assumption. Recently, several lines of evidence suggest that different species seem to employ distinct mechanisms to prevent the inheritance of paternal mtDNA. There are few studies in the literature on the molecular basis of sperm mtDNA elimination in mammals and paternal mtDNA transmission in humans. Endonuclease G (ENDOG) is a mitochondrial nuclease encoded by nuclear ENDOG gene. The critical importance of ENDOG gene on paternal mitochondrial elimination (PME) has been previously demonstrated in model organisms such as C. elegans and D. melanogaster. However, its mechanism in human is still unclear. Therefore, we aimed to evaluate whether nuclear ENDOG gene copy number could be a potential marker of paternal mtDNA transmission or not.Male factor infertility patients diagnosed with different infertility subgroups such as azoospermia, oligoteratozoospermia, astheno-teratozoospermia were included in this study: 13 infertile men and 25 healthy men as control group. Quantitative real-time polymerase chain reaction (qPCR) analysis and dual-color Fluorescence in situ hybridization (FISH) method were used to compare the groups. FISH method was applied to verify qPCR results and two signals were observed in nearly all patients. ENDOG gene copy number data were evaluated by comparing them with entire human mtDNA next-generation sequencing (NGS) analysis results obtained through bioinformatics and proteomics tools. Mitochondrial whole genome sequencing (WGS) data allowed determination of novel and reported variations such as single nucleotide polymorphisms (SNPs), multiple nucleotide polymorphism (MNP), insertion/deletion (INDEL). Missense variants causing amino acid substitution were filtered out from patients' mtDNA WGS data.Relative copy number of target ENDOG gene in male infertility patients [0.49 (0.31 - 0.77)] was lower than healthy controls [1.00 (0.66 - 1.51)], and statistical results showed significant differences between the groups (p < 0.01). A total of 38 missense variants were detected in the genes encoding the proteins involved in the respiratory chain complex. Moreover, we detected paternal mtDNA transmissions in the children of these patients who applied to assisted reproductive techniques.In conclusion, this study reveals that ENDOG gene may be an important factor for the PME mechanism in humans. To the best of our knowledge, this is the first study in humans about this topic and assessment of ENDOG gene sequencing and gene expression studies in a larger sample size including patients with male factor infertility would be our future project.

TMPRSS12 Functions in Meiosis and Spermiogenesis and Is Required for Male Fertility in Mice

Serine proteases are involved in many physiological activities as initiators of proteolytic cascades, and some members have been reported to play roles in male reproduction. Transmembrane serine protease 12 (TMPRSS12) has been shown to regulate sperm motility and uterotubal junction migration in mice, but its role in the testis remains unknown. In this study, we verified that TMPRSS12 was expressed in the spermatocytes and spermatids of testis and the acrosome of sperm. Mice deficient in Tmprss12 exhibited male sterility. In meiosis, TMPRSS12 was demonstrated to regulate synapsis and double-strand break repair; spermatocytes of Tmprss12^−/− mice underwent impaired meiosis and subsequent apoptosis, resulting in reduced sperm counts. During spermiogenesis, TMPRSS12 was found to function in the development of mitochondria; abnormal mitochondrial structure in Tmprss12^−/− sperm led to reduced availability of ATP, impacting sperm motility. The differential protein expression profiles of testes in Tmprss12^−/− and wild-type mice and further molecule identification revealed potential targets of TMPRSS12 related to meiosis and mitochondrial function. Besides, TMPRSS12 was also found to be involved in a series of sperm functions, including capacitation, acrosome reaction and sperm-egg interaction. These data imply that TMPRSS12 plays a role in multiple aspects of male reproduction.

Associations of Sperm mtDNA Copy Number, DNA Fragmentation Index, and Reactive Oxygen Species With Clinical Outcomes in ART Treatments

Recent studies have suggested that sperm mitochondrial DNA copy number (mtDNA-CN), DNA fragmentation index (DFI), and reactive oxygen species (ROS) content are crucial to sperm function. However, the associations between these measurements and embryo development and pregnancy outcomes in assisted reproductive technology (ART) remain unclear. Semen samples were collected from 401 participants, and seminal quality, parameters of sperm concentration, motility, and morphology were analyzed by a computer-assisted sperm analysis system. DFI, mtDNA-CN, and ROS levels were measured using sperm chromatin structure assay, real-time quantitative polymerase chain reaction, and ROS assay, respectively. Among the participants, 126 couples underwent ART treatments, including in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), and 79 of the couples had embryos transferred. In 401 semen samples, elevated mtDNA-CN and DFI were associated with poor seminal quality. In 126 ART couples, only mtDNA-CN was negatively correlated with the fertilization rate, but this correlation was not significant after adjusting for male age, female age, seminal quality, ART strategy, number of retrieved oocytes, controlled stimulation protocols, and cycle rank. Regarding pregnancy outcomes, sperm mtDNA-CN, ROS, and DFI were not associated with the clinical pregnancy rate or live birth rate in 79 transferred cases. In conclusion, increased mtDNA-CN and DFI in sperm jointly contributed to poor seminal quality, but sperm mtDNA-CN, ROS, and DFI were not associated with clinical outcomes in ART.

Sensitivity and applications of the PCR Single-Strand Conformation Polymorphism method

PCR Single-Strand Conformation Polymorphism is a method used to identify and detect mutations and is now well known for its many applications on living beings. This paper will discuss the experimental details, limitations and sensitivity of the PCR Single-Strand Conformation Polymorphism method in relation to all existing literature available to us until today. Genomic DNA extraction, PCR amplification and Single-Strand Conformation Polymorphism conditions (concentration of polyacrylamide slab gel electrophoresis, dissociation treatment of double- stranded DNA) and comparison with PCR Restriction Fragment Length Polymorphism are presented. Since its discovery in 1989, there have been many variations, innovations, and modifications of the method, which makes it very easy, safe, fast and for this reason widely applied in clinical diagnostic, forensic medicine, biochemical, veterinary, microbiological, food and environmental laboratories. One of the possible applications of the method is the diagnosis and identification of mutations in new strains of coronaviruses, because science needs more tools to tackle the problem of this pandemic. The PCR Single-Strand Conformation Polymorphism method can be applied in many cases provided that control samples are available and the required conditions of the method are achieved.

Body mass index and age correlate with antioxidant supplementation effects on sperm quality: Post hoc analyses from a double-blind placebo-controlled trial

Spermatozoa are vulnerable to lack of energy and oxidative stress as a result of elevated levels of reactive oxygen species. Therefore, it is essential that appropriate nutrients are available during maturation. This randomised, double‐blind, placebo‐controlled trial investigated the effect of 6‐month supplementation with carnitines and other micronutrients on sperm quality in 104 subjects with oligo‐ and/or astheno‐ and/or teratozoospermia with or without varicocele. Semen analyses were done at the beginning and end of the treatment. In addition to main analyses, post hoc analyses for age and body mass index (BMI) were carried out. Results were interpreted by dividing the population into two age and BMI classes. In 94 patients who completed the study, all sperm parameters increased in supplemented patients compared to the placebo group. A significant (p = .0272) difference in supplementation efficacy was observed for total motility on patients with varicocele and BMI < 25. In the same group, also the progressive motility was significantly superior (p = .0159). For Responder analysis, total motility results were confirmed in both the cited group (p = .0066) and in the varicocele group with BMI < 25 and age < 35 (p = .0078). This study suggests that supplementation is more effective in subjects with varicocele younger than 35 years with BMI < 25.

Mitochondrial transplantation as a potential and novel master key for treatment of various incurable diseases

Mitochondria are attractive cellular organelles which are so interesting in both basic and clinical research, especially after it was found that they were arisen as a bacterial intruder in ancient cells. Interestingly, even now, they are the focus of many investigations and their function and relevance to health and disease have remained open questions. More recently, research on mitochondria have turned out their potential application in medicine as a novel therapeutic intervention. The importance of this issue is highlighted when we know that mitochondrial dysfunction can be observed in a variety of diseases such as cardiovascular diseases, neurodegenerative diseases, ischemia, diabetes, renal failure, skeletal muscles disorders, liver diseases, burns, aging, and cancer progression. In other words, transplantation of viable mitochondria into the injured tissues would replace or augment damaged mitochondria, allowing the rescue of cells and restoration of the normal function. Therefore, mitochondrial transplantation would be revolutionary for the treatment of a variety of diseases in which conventional therapies have proved unsuccessful. Here, we describe pieces of evidence of mitochondrial transplantation, discuss and highlight the current and future directions to show why mitochondrial transplantation could be a master key for treatment of a variety of diseases or injuries.