Effects of Tcte1 knockout on energy chain transportation and spermatogenesis: implications for male infertility

STUDY QUESTION

Is the Tcte1 mutation causative for male infertility?

SUMMARY ANSWER

Our collected data underline the complex and devastating effect of the single-gene mutation on the testicular molecular network, leading to male reproductive failure.

WHAT IS KNOWN ALREADY

Recent data have revealed mutations in genes related to axonemal dynein arms as causative for morphology and motility abnormalities in spermatozoa of infertile males, including dysplasia of fibrous sheath (DFS) and multiple morphological abnormalities in the sperm flagella (MMAF). The nexin-dynein regulatory complex (N-DRC) coordinates the dynein arm activity and is built from the DRC1-DRC7 proteins. DRC5 (TCTE1), one of the N-DRC elements, has already been reported as a candidate for abnormal sperm flagella beating; however, only in a restricted manner with no clear explanation of respective observations.

STUDY DESIGN SIZE DURATION

Using the CRISPR/Cas9 genome editing technique, a mouse Tcte1 gene knockout line was created on the basis of the C57Bl/6J strain. The mouse reproductive potential, semen characteristics, testicular gene expression levels, sperm ATP, and testis apoptosis level measurements were then assessed, followed by visualization of N-DRC proteins in sperm, and protein modeling in silico. Also, a pilot genomic sequencing study of samples from human infertile males (n = 248) was applied for screening of TCTE1 variants.

PARTICIPANTS/MATERIALS SETTING METHODS

To check the reproductive potential of KO mice, adult animals were crossed for delivery of three litters per caged pair, but for no longer than for 6 months, in various combinations of zygosity. All experiments were performed for wild-type (WT, control group), heterozygous Tcte1+/- and homozygous Tcte1-/- male mice. Gross anatomy was performed on testis and epididymis samples, followed by semen analysis. Sequencing of RNA (RNAseq; Illumina) was done for mice testis tissues. STRING interactions were checked for protein-protein interactions, based on changed expression levels of corresponding genes identified in the mouse testis RNAseq experiments. Immunofluorescence in situ staining was performed to detect the N-DRC complex proteins: Tcte1 (Drc5), Drc7, Fbxl13 (Drc6), and Eps8l1 (Drc3) in mouse spermatozoa. To determine the amount of ATP in spermatozoa, the luminescence level was measured. In addition, immunofluorescence in situ staining was performed to check the level of apoptosis via caspase 3 visualization on mouse testis samples. DNA from whole blood samples of infertile males (n = 137 with non-obstructive azoospermia or cryptozoospermia, n = 111 samples with a spectrum of oligoasthenoteratozoospermia, including n = 47 with asthenozoospermia) was extracted to perform genomic sequencing (WGS, WES, or Sanger). Protein prediction modeling of human-identified variants and the exon 3 structure deleted in the mouse knockout was also performed.

MAIN RESULTS AND THE ROLE OF CHANCE

No progeny at all was found for the homozygous males which were revealed to have oligoasthenoteratozoospermia, while heterozygous animals were fertile but manifested oligozoospermia, suggesting haploinsufficiency. RNA-sequencing of the testicular tissue showed the influence of Tcte1 mutations on the expression pattern of 21 genes responsible for mitochondrial ATP processing or linked with apoptosis or spermatogenesis. In Tcte1-/- males, the protein was revealed in only residual amounts in the sperm head nucleus and was not transported to the sperm flagella, as were other N-DRC components. Decreased ATP levels (2.4-fold lower) were found in the spermatozoa of homozygous mice, together with disturbed tail:midpiece ratios, leading to abnormal sperm tail beating. Casp3-positive signals (indicating apoptosis) were observed in spermatogonia only, at a similar level in all three mouse genotypes. Mutation screening of human infertile males revealed one novel and five ultra-rare heterogeneous variants (predicted as disease-causing) in 6.05% of the patients studied. Protein prediction modeling of identified variants revealed changes in the protein surface charge potential, leading to disruption in helix flexibility or its dynamics, thus suggesting disrupted interactions of TCTE1 with its binding partners located within the axoneme.

LARGE SCALE DATA

All data generated or analyzed during this study are included in this published article and its supplementary information files. RNAseq data are available in the GEO database (https://www.ncbi.nlm.nih.gov/geo/) under the accession number GSE207805. The results described in the publication are based on whole-genome or exome sequencing data which includes sensitive information in the form of patient-specific germline variants. Information regarding such variants must not be shared publicly following European Union legislation, therefore access to raw data that support the findings of this study are available from the corresponding author upon reasonable request.

LIMITATIONS REASONS FOR CAUTION

In the study, the in vitro fertilization performance of sperm from homozygous male mice was not checked.

WIDER IMPLICATIONS OF THE FINDINGS

This study contains novel and comprehensive data concerning the role of TCTE1 in male infertility. The TCTE1 gene is the next one that should be added to the 'male infertility list' because of its crucial role in spermatogenesis and proper sperm functioning.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by National Science Centre in Poland, grants no.: 2015/17/B/NZ2/01157 and 2020/37/B/NZ5/00549 (to M.K.), 2017/26/D/NZ5/00789 (to A.M.), and HD096723, GM127569-03, NIH SAP #4100085736 PA DoH (to A.N.Y.). The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

ESX1 gene as a potential candidate responsible for male infertility in nonobstructive azoospermia

Infertility is a problem that affects approximately 15% of couples, and male infertility is responsible for 40-50% of these cases. The cause of male infertility is still poorly diagnosed and treated. One of the prominent causes of male infertility is disturbed spermatogenesis, which can lead to nonobstructive azoospermia (NOA). Whole-genome sequencing (WGS) allows us to identify novel rare variants in potentially NOA-associated genes, among others, in the ESX1 gene. The aim of this study was to activate the ESX1 gene using CRISPRa technology in human germ cells (testicular seminoma cells-TCam-2). Successful activation of the ESX1 gene in TCam-2 cells using the CRISPRa system was achieved, and the expression level of the ESX1 gene was significantly higher in modified TCam-2 cells than in WT cells or the negative control with nontargeted gRNA (p < 0.01). Using RNA-seq, a network of over 50 genes potentially regulated by the ESX1 gene was determined. Finally, 6 genes, NANOG, CXCR4, RPS6KA5, CCND1, PDE1C, and LINC00662, participating in cell proliferation and differentiation were verified in azoospermic patients with and without a mutation in the ESX1 gene as well as in men with normal spermatogenesis, where inverse correlations in the expression levels of the observed genes were noted.

Long-term cryopreservation of dental stem cells

Cryopreservation is a procedure of a long-term storage of cells and/or tissues at a temperature that prevents cell divisions and metabolic processes. Due to ability to self-renewal and differentiation into more specialised cells, stem cells may be helpful in repairing of other damaged organs or tissues. Cryopreservation allows the frozen genetic material to maintain its biological properties for a long time. Therefore, there is a real chance for some samples to be used in the future therapy of the pathological conditions that at present remain incurable because of the current state of knowledge. The purpose of this review is to describe the modern methods of extraction, preservation, and storage of dental stem cells at low temperatures in particular procedure of collecting and transporting tissues intended for freezing, precise characteristics of stem cells of dentary origin and methods of their isolation using Enzymatic Digestion and Spontaneous Outgrowth. In the paper are also presented technical details of the protocols of rapid rate freezing, controlled rate milling and freezing in a magnetic field (magnetic freezing) which provides precise information about procedures of thawing cells and unfavourable effect of negative temperature on the biological properties of stem cells. Dental tissues may constitute a rich source of stem cells. The inexpensive, simple and quick procedure of their extraction is minimally invasive and does not pose a threat to the donor's organism. Transferring autologous cells within the same organism does not present a potential risk of transplant rejection and thereof does not raise ethical controversies. Laboratory procedures including cell preparation, its characteristics and genetic features, basics on the process of freezing, thawing, as well as quality control essentials have been also outlined.

Genomic study of TEX15 variants: prevalence and allelic heterogeneity in men with spermatogenic failure

Introduction: Human spermatogenesis is a highly intricate process that requires the input of thousands of testis-specific genes. Defects in any of them at any stage of the process can have detrimental effects on sperm production and/or viability. In particular, the function of many meiotic proteins encoded by germ cell specific genes is critical for maturation of haploid spermatids and viable spermatozoa, necessary for fertilization, and is also extremely sensitive to even the slightest change in coding DNA. Methods: Here, using whole exome and genome approaches, we identified and reported novel, clinically significant variants in testis-expressed gene 15 (TEX15), in unrelated men with spermatogenic failure (SPGF). Results: TEX15 mediates double strand break repair during meiosis. Recessive loss-of-function (LOF) TEX15 mutations are associated with SPGF in humans and knockout male mice are infertile. We expand earlier reports documenting heterogeneous allelic pathogenic TEX15 variants that cause a range of SPGF phenotypes from oligozoospermia (low sperm) to nonobstructive azoospermia (no sperm) with meiotic arrest and report the prevalence of 0.6% of TEX15 variants in our patient cohort. Among identified possible LOF variants, one homozygous missense substitution c.6835G>A (p.Ala2279Thr) co-segregated with cryptozoospermia in a family with SPGF. Additionally, we observed numerous cases of inferred in trans compound heterozygous variants in TEX15 among unrelated individuals with varying degrees of SPGF. Variants included splice site, insertions/deletions (indels), and missense substitutions, many of which resulted in LOF effects (i.e., frameshift, premature stop, alternative splicing, or potentially altered posttranslational modification sites). Conclusion: In conclusion, we performed an extensive genomic study of familial and sporadic SPGF and identified potentially damaging TEX15 variants in 7 of 1097 individuals of our combined cohorts. We hypothesize that SPGF phenotype severity is dictated by individual TEX15 variant's impact on structure and function. Resultant LOFs likely have deleterious effects on crossover/recombination in meiosis. Our findings support the notion of increased gene variant frequency in SPGF and its genetic and allelic heterogeneity as it relates to complex disease such as male infertility.

Epigenetic markers in the embryonal germ cell development and spermatogenesis

Spermatogenesis is the process of generation of male reproductive cells from spermatogonial stem cells in the seminiferous epithelium of the testis. During spermatogenesis, key spermatogenic events such as stem cell self-renewal and commitment to meiosis, meiotic recombination, meiotic sex chromosome inactivation, followed by cellular and chromatin remodeling of elongating spermatids occur, leading to sperm cell production. All the mentioned events are at least partially controlled by the epigenetic modifications of DNA and histones. Additionally, during embryonal development in primordial germ cells, global epigenetic reprogramming of DNA occurs. In this review, we summarized the most important epigenetic modifications in the particular stages of germ cell development, in DNA and histone proteins, starting from primordial germ cells, during embryonal development, and ending with histone-to-protamine transition during spermiogenesis.

New Technologies Based on Stem Cell-Therapies in Regenerative Medicine and Reproductive Biology

Stem cells seem to hold major promise for contemporary medicine, one which could almost be more significant than a discovery of DNA and ultimate its relevance for organismal integration in the past century [...].

Varicocelectomy improves sperm parameters, sperm DNA integrity as well as the other critical semen features

Varicocele is a major entity defined within male infertility. In this report we have studied the influence of laparoscopic varicocelectomy on semen quality, biochemical parameters of seminal plasma and sperm DNA fragmentation. In this study, the semen samples from patients with left-side varicocele of grade II-III before and after laparoscopic varicocelectomy were compared to healthy individuals and separated into three groups. The volume of semen, sperm concentration (106/ml), motility (%), viability (%) and normal morphology (%) were assessed. Total antioxidant capacity (TAC), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA) together with other biochemical substances in seminal plasma as alpha-glucosidase (α-Glu), fructose (Fr) and citric acid (CA) were determined by ELISA method. The spermatozoa activity including ion-transports through sodium, potassium ATPase (Na⁺, K⁺-ATPase) and calcium, magnesium ATPase (Ca²⁺, Mg²⁺-ATPase) were determined by using spectrophotometry. In addition, flow cytometry method for detection of sperm DNA fragmentation was used. The results showed, that three months after varicocelectomy such intervention led to significant postoperative improvement in volume of semen (p<0.001), total sperm count (p<0.001), sperm motility (p<0.001) and spermatozoa with normal morphology (p<0.001). We found decreased α-Glu levels due to varicocelectomy (p<0.05). There has been shown a high positive correlation between Na⁺, K⁺-ATPase and Ca²⁺, Mg²⁺-ATPase activity with total number of spermatozoa (p<0.05). The TAC levels and DNA fragmentation values after varicocelectomy can be considered as significant indicators of good prognosis after surgical intervention. It has to be emphasized that α-Glu levels and total sperm count expressed statistically significant both positive and negative predictive values for semen assessment. Varicocelectomy may lead to significant improvement of semen quality although the observations must be correlated with clinical pregnancies observed thereafter.

Standards in semen examination: publishing reproducible and reliable data based on high-quality methodology

Biomedical science is rapidly developing in terms of more transparency, openness and reproducibility of scientific publications. This is even more important for all studies that are based on results from basic semen examination. Recently two concordant documents have been published: the 6th edition of the WHO Laboratory Manual for the Examination and Processing of Human Semen, and the International Standard ISO 23162:2021. With these tools, we propose that authors should be instructed to follow these laboratory methods in order to publish studies in peer-reviewed journals, preferable by using a checklist as suggested in an Appendix to this article.

Male Infertility Coexists with Decreased Sperm Genomic Integrity and Oxidative Stress in Semen Irrespective of Leukocytospermia

Our research was designed to verify the relationship between male infertility, basic semen characteristics (with respect to detailed sperm morphology), sperm DNA fragmentation (SDF), oxidation-reduction potential in semen (ORP), and leukocytospermia. The obtained results showed that infertile groups (with or without leukocytospermia) had significantly lower basic semen characteristics and higher SDF, raw ORP, and static ORP (sORP) than fertile controls. The thresholds of 13% SDF (AUC = 0.733) and 1.40 sORP (AUC = 0.857) were predictive values for discriminating infertile from fertile men. In infertile groups, a higher prevalence and risk for >13% SDF and >1.40 sORP were revealed. Unexpectedly, leukocytospermic subjects had lower sORP, prevalence, and risk for >1.40 sORP than leukocytospermic-negative men. These groups did not differ in SDF and raw ORP. Both SDF and sORP negatively correlated with basic semen parameters but positively correlated with sperm head and midpiece defects. sORP positively correlated with sperm tail defects, immature sperm cells with excess residual cytoplasm, and SDF. In turn, raw ORP negatively correlated with sperm count but positively correlated with SDF and sORP. These findings indicate that (1) there is a relationship between male infertility, SDF, and OS in semen; (2) in infertile men, there is a clinically significant risk of SDF and OS irrespective of leukocytospermia; and (3) the assessment of SDF and oxidative stress should be independent of leukocytospermia.

Genomic testing for copy number and single nucleotide variants in spermatogenic failure

PURPOSE

To identify clinically significant genomic copy number (CNV) and single nucleotide variants (SNV) in males with unexplained spermatogenic failure (SPGF).

MATERIALS AND METHODS

Peripheral blood DNA from 97/102 study participants diagnosed with oligozoospermia, severe oligozoospermia, or non-obstructive azoospermia (NOA) was analyzed for CNVs via array comparative genomic hybridization (aCGH) and SNVs using whole-exome sequencing (WES).

RESULTS

Of the 2544 CNVs identified in individuals with SPGF, > 90% were small, ranging from 0.6 to 75 kb. Thirty, clinically relevant genomic aberrations, were detected in 28 patients (~ 29%). These included likely diagnostic CNVs in 3/41 NOA patients (~ 7%): 1 hemizygous, intragenic TEX11 deletion, 1 hemizygous DDX53 full gene deletion, and 1 homozygous, intragenic STK11 deletion. High-level mosaicism for X chromosome disomy (~ 10% 46,XY and ~ 90% 47,XXY) was also identified in 3 of 41 NOA patients who previously tested normal with conventional karyotyping. The remaining 24 CNVs detected were heterozygous, autosomal recessive carrier variants. Follow-up WES analysis confirmed 8 of 27 (30%) CNVs (X chromosome disomy excluded). WES analysis additionally identified 13 significant SNVs and/or indels in 9 patients (~ 9%) including X-linked AR, KAL1, and NR0B1 variants.

CONCLUSION

Using a combined genome-wide aCGH/WES approach, we identified pathogenic and likely pathogenic SNVs and CNVs in 15 patients (15%) with unexplained SPGF. This value equals the detection rate of conventional testing for aneuploidies and is considerably higher than the prevalence of Y chromosome microdeletions. Our results underscore the importance of comprehensive genomic analysis in emerging diagnostic testing of complex conditions like male infertility.

Effect of miR-195 inhibition on human skeletal muscle-derived stem/progenitor cells

BACKGROUND

The application of a circulating miR-195 inhibitor could be a helping factor in the in vitro model of human skeletal muscle-derived stem/progenitor cells (SkMDS/PCs). Previously, microRNA-195 (miR-195) expression has been reported to be a negative factor for myogenesis.

AIMS

The study aimed to obtain anti-apoptotic and anti-aging effects in in vitro cultured myoblasts and to improve their ability to form myotubes by suppressing miR-195 expression.

METHODS

Human wild-type (WT) SkMDS/PC cells incubated with control (nonspecific) miRNA inhibitor and miR-195-inhibited SkMDS/PCs were studied. Functional assays (myotube formation and cell aging), antioxidant, and myogenic gene expression analyses were performed at two time points, at the seventh and eleventh cell passages.

RESULTS

Myotube formation was found to be almost 2-fold higher in the miR-195-inhibited SkMDS/PCs population (P < 0.05) compared to WT cells. miR-195 inhibition did not appear to affect cell aging or rejuvenate human SkMDS/PCs. Antioxidant (SOD3 and FOXO) gene expression was augmented in the miR-195-inhibited SkMDS/PCs population, but no positive effect on the remaining antioxidant genes (SOD1, SOD2, and catalase) was observed. A significant increase in MyoD gene expression with a concomitant decrease in MyoG (P < 0.05) was further documented in miR-195- -inhibited SkMDS/PCs compared to WT cells (the eleventh cell passage).

CONCLUSIONS

The performed studies may lead to the preconditioning of myogenic stem cells to extend their potential for pro-regenerative activity. The miR-195 inhibitor may serve as a conditioning factor augmenting selective antioxidant gene expression and proliferative potential of SkMDS/PCs, but it does not have an impact on cell aging and/ or apoptosis.

Global 5mC and 5hmC DNA Levels in Human Sperm Subpopulations with Differentially Protaminated Chromatin in Normo- and Oligoasthenozoospermic Males

Epigenetic modifications play a special role in the male infertility aetiology. Published data indicate the link between sperm quality and sperm chromatin protamination. This study aimed to determine the relationship between methylation (5mC) and hydroxymethylation (5hmC) in sperm DNA, with respect to sperm chromatin protamination in three subpopulations of fertile normozoospermic controls and infertile patients with oligo-/oligoasthenozoospermia. For the first time, a sequential staining protocol was applied, which allowed researchers to analyse 5mC/5hmC levels by immunofluorescence staining, with a previously determined chromatin protamination status (aniline blue staining), using the same spermatozoa. TUNEL assay determined the sperm DNA fragmentation level. The 5mC/5hmC levels were diversified with respect to chromatin protamination status in both studied groups of males, with the highest values observed in protaminated spermatozoa. The linkage between chromatin protamination and 5mC/5hmC levels in control males disappeared in patients with deteriorated semen parameters. A relationship between 5mC/5hmC and sperm motility/morphology was identified in the patient group. Measuring the 5mC/5hmC status of sperm DNA according to sperm chromatin integrity provides evidence of correct spermatogenesis, and its disruption may represent a prognostic marker for reproductive failure.

The Role of Seminal Oxidative Stress Scavenging System in the Pathogenesis of Sperm DNA Damage in Men Exposed and Not Exposed to Genital Heat Stress

Responding to the need for the verification of some experimental animal studies showing the involvement of oxidative stress in germ cell damage in the heat-induced testis, we investigated the possibility of a direct relationship between seminal oxidative stress markers (total antioxidant capacity, catalase activity, superoxide dismutase activity, and malondialdehyde concentration) and ejaculated sperm chromatin/DNA integrity (DNA fragmentation and chromatin condensation abnormalities) in distinct groups of men exposed and not exposed to prolonged scrotal hyperthermia. A statistical increase in the proportion of sperm with DNA fragmentation was observed in all the studied subgroups compared to the fertile men. In turn, the groups subjected to heat stress as professional drivers or infertile men with varicocele presented greater disturbances in the oxidative stress scavenging system than men not exposed to genital heat stress. Based on the comparative analysis of the studied parameters, we can conclude that alterations in the seminal oxidative stress scavenging system are directly engaged in the pathogenesis of ejaculated sperm DNA damage regardless of the intensity of the impact of thermal insult. To the best of our knowledge, this study, for the first time, revealed the co-existence of oxidative stress and sperm DNA damage in the semen of professional drivers.

Molecular imaging of myogenic stem/progenitor cells with [18F]-FHBG PET/CT system in SCID mice model of post-infarction heart

Preclinical and clinical studies have shown that stem cells can promote the regeneration of damaged tissues, but therapeutic protocols need better quality control to confirm the location and number of transplanted cells. This study describes in vivo imaging while assessing reporter gene expression by its binding to a radiolabelled molecule to the respective receptor expressed in target cells. Five mice underwent human skeletal muscle-derived stem/progenitor cell (huSkMDS/PC EF1-HSV-TK) intracardial transplantation after induction of myocardial infarction (MI). The metabolic parameters of control and post-infarction stem progenitor cell-implanted mice were monitored using 2-deoxy-18F-fluorodeoxyglucose ([18F]-FDG) before and after double promotor/reporter probe imaging with 9-(4-18F-fluoro-3-[hydroxymethyl]butyl)guanine ([18F]-FHBG) using positron emission tomography (PET) combined with computed tomography (CT). Standardized uptake values (SUVs) were then calculated based on set regions of interest (ROIs). Experimental animals were euthanized after magnetic resonance imaging (MRI). Molecular [18F]-FHBG imaging of myogenic stem/progenitor cells in control and post-infarction mice confirmed the survival and proliferation of transplanted cells, as shown by an increased or stable signal from the PET apparatus throughout the 5 weeks of monitoring. huSkMDS/PC EF1-HSV-TK transplantation improved cardiac metabolic ([18F]-FDG with PET) and haemodynamic (MRI) parameters. In vivo PET/CT and MRI revealed that the precise use of a promotor/reporter probe incorporated into stem/progenitor cells may improve non-invasive monitoring of targeted cellular therapy in the cardiovascular system.

pNiPAM-Nanoparticle-Based Antiapoptotic Approach for Pro-Regenerative Capacity of Skeletal Myogenic Cells

The biocompatibility of pNiPAM (Poly N-isopropylacrylamide) copolymers has been examined and they did not exert any cytotoxic effects. Their properties and vulnerable temperature characteristics make them candidates for use in medical applications. We synthesized a well-characterized nanoparticles-based cargo system that would effectively deliver a biological agent to human skeletal myogenic cells (SkMCs); among other aspects, a downregulating apoptotic pathway potentially responsible for poor regeneration of myocardium. We confirmed the size of the pNiPAM based spheres at around 100 nm and the nanomeric shape of nanoparticles (NP) obtained. We confirmed that 33 °C is the adequate temperature for phase transition. We performed the dynamics of cargo release. A small amount of examined protein was detected at 10 min after reaching LCTS (lower critical solution temperature). The presented results of the test with BSA (bovine serum albumin) and doxorubicin loaded into nanoparticles showed a similar release profile for both substances. SkMCs incubated with NP loaded with antiapoptotic agent, BCB (Bax channel blocker), significantly diminished cell apoptosis (p < 0.01). Moreover, the lowest apoptotic level was detected in SkMCs treated with camptothecin and simultaneously incubated with pNiPAMs loaded with BCB. Application of nanoparticles loaded with BCB or subjected to BCB alone did not, however, diminish the amount of apparently necrotic cells.

The Negative Impact of Varicocele on Basic Semen Parameters, Sperm Nuclear DNA Dispersion and Oxidation-Reduction Potential in Semen

Since varicocele is so common in infertile men, this study intends to analyse the relationships between varicocele and conventional semen characteristics, sperm nuclear DNA dispersion and oxidation-reduction potential (ORP) in semen. Varicocele-positive and varicocele-negative infertile men (study groups) showed significantly lower standard sperm parameters and higher sperm DNA fragmentation (SDF) and ORP in semen than healthy volunteers and subjects with proven fertility (control groups). A lower proportion of low SDF levels (0–15% SDF) and higher incidence of high SDF levels (>30% SDF), as well as a higher prevalence of high ORP values (>1.37 mV/10⁶ sperm/mL), were found in the study groups vs. the control groups. Moreover, infertile men had significantly lower odds ratios (ORs) for low SDF levels and significantly higher ORs for high SDF levels and high ORP. SDF and ORP were negatively correlated with sperm number, morphology, motility and vitality. Furthermore, a significant positive correlation was found between SDF and ORP. The obtained results suggest that disorders of spermatogenesis may occur in varicocele-related infertility. These abnormalities are manifested not only by reduced standard semen parameters but also by decreased sperm DNA integrity and simultaneously increased oxidative stress in semen.

The role of mitochondria in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is an X-linked lethal disorder caused by mutations in the dystrophin gene. Progression of this disease may lead to cardiomyopathy and respiratory failure, which are the main causes of death among DMD patients. Lack of dystrophin affects cellular myogenic function and related organelles. Dystrophin deficiency results in intracellular Ca²⁺ dysregulation, mitochondrial dysfunction and induces elevated production of reactive oxygen species (ROS). Due to current findings, mitochondria may be also a potential target for DMD therapy. In this review we attempted to provide an insight into the role of mitochondria in perpetuation of DMD disease.

Analysis of sperm chromosomes in six carriers of rare and common Robertsonian translocations

Introduction: Robertsonian translocation (RobT) is the central fusion of the long arms of two acrocentric chromosomes, leading to 45 chromosomes in humans. The most common ones are rob(13;14) and rob(14;21) (91%). Other types of RobT are so-called rare cases. In the general population RobTs occur with a frequency of approximately 0.123%, but among men with reproductive failure this value rises 9-fold. Infertility in RobT carriers is associated with the formation of unbalanced spermatozoa resulting from segregation of the chromosomes involved in trivalent during the meiotic prophase. In spermatozoa of many RobT carriers an increased level of chromosomal aneuploidy is observed. Materials and Methods: We examined the hyperhaploidy level of chromosomes 7, 9, 18, 21, 22, X and Y in spermatozoa of 6 RobT unrelated carriers: two carriers with rare rob(13;15), one with rare rob(13;22), and three of the common rob(13;14). Results were compared with the control data from a group of 7 fertile men with a normal karyotype. Fluorescent in situ hybridization (FISH) was applied. Results: We found an increased level of sperm aneuploidy regarding at least one of the analyzed chromosomes in each of the carriers, while in rare RobTs interchromosomal effect (ICE) was observed. Meiotic segregation pattern of a rare rob(13;15) carrier revealed the 76% of normal /balanced spermatozoa. Disucussion: Due to the relatively high population frequency of RobTs, their influence on reproductive failure, hight risk of imbalancement in prenatal diagnosis (7%), and small amount of data for rare RobTs, each newly characterized case is valuable in genetic counseling.

Seminal Plasma Analysis of Oxidative Stress in Different Genitourinary Topographical Regions Involved in Reproductive Tract Disorders Associated with Genital Heat Stress

The pathophysiological mechanisms responsible for male subfertility/infertility caused by or complicated by genital heat stress remains unclear in many respects. Because seminal plasma creates the environment for the proper functioning of spermatozoa, in this study, we verified the associations among standard spermiograms, seminal biochemical parameters (neutral alpha-glucosidase, fructose, and citric acid) and oxidative stress markers (total antioxidant capacity, catalase activity, superoxide dismutase activity, and malondialdehyde concentration) in distinct entities associated with male infertility with and without long-time exposure to local hyperthermia. We demonstrated that men exposed to prolonged environmental or clinically recognized local heat stress in adulthood may suffer from dysregulation of seminal antioxidant components, which can be directly associated with epididymal and prostate function. The comparative analysis of the studied parameters showed numerous correlations among all biochemical parameters (particularly neutral alpha-glucosidase) with low standard semen quality in almost all the investigated infertile groups. In light of the data obtained in this originally designed study, we conclude that more attention should be paid to the epididymis and accessory gland function in subfertile and infertile men exposed to genital heat stress, especially in the context of novel treatment algorithms (targeted therapies).

Familial Infertility (Azoospermia and Cryptozoospermia) in Two Brothers-Carriers of t(1;7) Complex Chromosomal Rearrangement (CCR): Molecular Cytogenetic Analysis

Structural aberrations involving more than two breakpoints on two or more chromosomes are known as complex chromosomal rearrangements (CCRs). They can reduce fertility through gametogenesis arrest developed due to disrupted chromosomal pairing in the pachytene stage. We present a familial case of two infertile brothers (with azoospermia and cryptozoospermia) and their mother, carriers of an exceptional type of CCR involving chromosomes 1 and 7 and three breakpoints. The aim was to identify whether meiotic disruption was caused by CCR and/or genomic mutations. Additionally, we performed a literature survey for male CCR carriers with reproductive failures. The characterization of the CCR chromosomes and potential genomic aberrations was performed using: G-banding using trypsin and Giemsa staining (GTG banding), fluorescent in situ hybridization (FISH) (including multicolor FISH (mFISH) and bacterial artificial chromosome (BAC)-FISH), and genome-wide array comparative genomic hybridization (aCGH). The CCR description was established as: der(1)(1qter->1q42.3::1p21->1q42.3::7p14.3->7pter), der(7)(1pter->1p2 1::7p14.3->7qter). aCGH revealed three rare genes variants: ASMT, GARNL3, and SESTD1, which were ruled out due to unlikely biological functions. The aCGH analysis of three breakpoint CCR regions did not reveal copy number variations (CNVs) with biologically plausible genes. Synaptonemal complex evaluation (brother-1; spermatocytes II/oligobiopsy; the silver staining technique) showed incomplete conjugation of the chromosomes. Associations between CCR and the sex chromosomes (by FISH) were not found. A meiotic segregation pattern (brother-2; ejaculated spermatozoa; FISH) revealed 29.21% genetically normal/balanced spermatozoa. The aCGH analysis could not detect smaller intergenic CNVs of few kb or smaller (indels of single exons or few nucleotides). Since chromosomal aberrations frequently do not affect the phenotype of the carrier, in contrast to the negative influence on spermatogenesis, there is an obvious need for genomic sequencing to investigate the point mutations that may be responsible for the differences between the azoospermic and cryptozoospermic phenotypes observed in a family. Progeny from the same parents provide a unique opportunity to discover a novel genomic background of male infertility.

How much, if anything, do we know about sperm chromosomes of Robertsonian translocation carriers?

In men with oligozoospermia, Robertsonian translocations (RobTs) are the most common type of autosomal aberrations. The most commonly occurring types are rob(13;14) and rob(14;21), and other types of RobTs are described as ‘rare’ cases. Based on molecular research, all RobTs can be broadly classified into Class 1 and Class 2. Class 1 translocations produce the same breakpoints within their RobT type, but Class 2 translocations are predicted to form during meiosis or mitosis through a variety of mechanisms, resulting in variation in the breakpoint locations. This review seeks to analyse the available data addressing the question of whether the molecular classification of RobTs into Classes 1 and 2 and/or the type of DD/GG/DG symmetry of the involved chromosomes is reflected in the efficiency of spermatogenesis. The lowest frequency value calculated for the rate of alternate segregants was found for rob(13;15) carriers (Class 2, symmetry DD) and the highest for rob(13;21) carriers (Class 2, DG symmetry). The aneuploidy values for the rare RobT (Class 2) and common rob(14;21) (Class 1) groups together exhibited similarities while differing from those for the common rob(13;14) (Class 1) group. Considering the division of RobT carriers into those with normozoospermia and those with oligoasthenozoospermia, it was found that the number of carriers with elevated levels of aneuploidy was unexpectedly quite similar and high (approx. 70%) in the two subgroups. The reason(s) that the same RobT does not always show a similar destructive effect on fertility was also pointed out.

Human skeletal muscle-derived stem/progenitor cells modified with connexin-43 prevent arrhythmia in rat post-infarction hearts and influence gene expression in the myocardium

Stem cell therapy in combination with genetic modification (e.g., transfection with the coding sequence for the connexion 43 gene, GJA1) may solve the problems associated with the occurrence of additional (secondary) stimulation in the post-infarcted heart (arrhythmia). Human skeletal muscle-derived stem/progenitor cells (SkMDS/PCs) were transfected with the pCiNeo-GJA1 plasmid at an efficiency of approximately 96%. Gene overexpression was assessed using qPCR, and subsequent analysis revealed that GJA1 expression increased more than 40-fold in SkMDS/PCs transfected with the appropriate coding sequence (SkMDS/PCsCX43) compared to that of the 'native' SkMDS/PCs control (SkMDS/PCsWT). Enhanced (4-fold) protein expression of connexin-43 was also confirmed by Western immunoblotting. Furthermore, using the arrhythmic score, we demonstrated the positive effects of SkMDS/PCsCX43 cell intervention in reducing additional secondary stimulations in rat post-infarcted hearts compared with that of wild-type cell delivery. Selected gene responses (Kcnq1, Cacna1c, Ncx1, Serca2a, and Tgfb1) showed significantly altered expression profiles in the rat myocardium upon intervention with SkMDS/PCsCX43. The genetic modification of human skeletal muscle-derived stem/progenitor cells with connexin-43 prevented the pro-arrhythmic effects of myogenic implanted stem cells on the host myocardium and positively influenced myocardial gene expression profiles in respect to myocardium conductivity.

Tissue-specific promoter-based reporter system for monitoring cell differentiation from iPSCs to cardiomyocytes

The possibility of using stem cell-derived cardiomyocytes opens a new platform for modeling cardiac cell differentiation and disease or the development of new drugs. Progress in this field can be accelerated by high-throughput screening (HTS) technology combined with promoter reporter system. The goal of the study was to create and evaluate a responsive promoter reporter system that allows monitoring of iPSC differentiation towards cardiomyocytes. The lentiviral promoter reporter system was based on troponin 2 (TNNT2) and alpha cardiac actin (ACTC) with firefly luciferase and mCherry, respectively. The system was evaluated in two in vitro models. First, system followed the differentiation of TNNT2-luc-T2A-Puro-mCMV-GFP and hACTC-mcherry-WPRE-EF1-Neo from transduced iPSC line towards cardiomyocytes and revealed the significant decrease in both inserts copy number during the prolonged in vitro cell culture (confirmed by I-FISH, ddPCR, qPCR). Second, differentiated and contracting control cardiomyocytes (obtained from control non-reporter transduced iPSCs) were subsequently transduced with TNNT2-luc-T2A-Puro-CMV-GFP and hACTC-mcherry-WPRE-EF1-Neo lentiviruses to observe the functionality of obtained cardiomyocytes. Our results indicated that the reporter modified cell lines can be used for HTS applications, but it is essential to monitor the stability of the reporter sequence during extended cell in vitro culture.

Novel Mutations Segregating with Complete Androgen Insensitivity Syndrome and their Molecular Characteristics

We analyzed three cases of Complete Androgen Insensitivity Syndrome (CAIS) and report three hitherto undisclosed causes of the disease. RNA-Seq, Real-timePCR, Western immunoblotting, and immunohistochemistry were performed with the aim of characterizing the disease-causing variants. In case No.1, we have identified a novel androgen receptor (AR) mutation (c.840delT) within the first exon in the N-terminal transactivation domain. This thymine deletion resulted in a frameshift and thus introduced a premature stop codon at amino acid 282. In case No.2, we observed a nonsynonymous mutation in the ligand-binding domain (c.2491C>T). Case No.3 did not reveal AR mutation; however, we have found a heterozygous mutation in CYP11A1 gene, which has a role in steroid hormone biosynthesis. Comparative RNA-Seq analysis of CAIS and control revealed 4293 significantly deregulated genes. In patients with CAIS, we observed a significant increase in the expression levels of PLCXD3, TM4SF18, CFI, GPX8, and SFRP4, and a significant decrease in the expression of SPATA16, TSACC, TCP10L, and DPY19L2 genes (more than 10-fold, p < 0.05). Our findings will be helpful in molecular diagnostics of patients with CAIS, as well as the identified genes could be also potential biomarkers for the germ cells differentiation process.

Age-related changes in human sperm DNA integrity

Abnormal standard semen characteristics and reduced sperm chromatin maturity can appear with increasing male age. However, the influence of paternal age on semen parameters is still controversial. Therefore, this study was designed to estimate the influence of paternal age not only on conventional semen characteristics but also on sperm DNA integrity. This research was carried out on ejaculated sperm cells obtained from men (n = 1124) aged ≥40 y and <40 y. Our data revealed a decreased semen volume and an increased percentage of DFI (sperm DNA fragmentation index) in older men compared to younger men in the entire study cohort, in men with normozoospermia and in men with abnormal semen parameters. Moreover, there was a higher incidence of sperm DNA damage (>10% DFI, low fertility potential) in the groups of men aged ≥40 y than in the groups of men aged <40 y. Older men had over twice the odds ratio for high sperm DNA damage as younger men. Our findings suggest a detrimental effect of advanced paternal age on sperm chromatin integrity. The data show that the evaluation of sperm DNA has greater clinical utility than standard semen analysis in case of male fertility potential assessment.

Immunological Characteristics and Properties of Glial Restricted Progenitors of Mice, Canine Primary Culture Suspensions, and Human QSV40 Immortalized Cell Lines for Prospective Therapies of Neurodegenerative Disorders

Neurodegeneration can be defined as a process in which neuronal structures and functions undergo changes leading to reduced neuronal survival and increased cell death in the central nervous system (CNS). Neuronal degeneration in specific regions of the CNS is a hallmark of many neurodegenerative disorders, and there is reliable proof that neural stem cells bring therapeutic benefits in treatment of neurological lesions. However, effective therapy with neural stem cells is associated with their biological properties. The assessment of immunological properties and comprehensive studies on the biology of glial restricted progenitors (GRP) are necessary prior to the application of these cells in humans. This study provides an in vitro characterization of the QSV40 glial human cell line, as well as murine and canine primary culture suspensions of GRPs and their mature, astrocytic forms using flow cytometry and immunohistochemical staining. Cytokines and chemokines released by GRPs were assessed by Multiplex ELISA. Some immunological differences observed among species suggest the necessity of reconsidering the pre-clinical model, and that careful testing of immunomodulatory strategies is required before cell transplantation into the CNS can be undertaken.

New mutation causing androgen insensitivity syndrome - a case report and review of literature

Androgen insensitivity syndrome (AIS) is a congenital disorder in which a defect in the androgen receptor (AR) gene leads to cellular resistance to androgens. Defects in the AR gene, located on the X chromosome, result in the development of a feminine phenotype in chromosomally male (46, XY) individuals. In this case report, we present a 44 years old patient with complete androgen insensitivity syndrome (CAIS) initially presenting with primary amenorrhea. The patient underwent a full clinical evaluation, revealing hypoplastic vagina and a lack of uterus and ovaries. Hormonal evaluation revealed markedly elevated testosterone, FSH, and LH serum concentrations. Diagnostic imaging, including pelvic MRI, confirmed the presence of two solid masses in the inguinal canals (right 26 × 13 mm, left 25 × 15 mm). The patient underwent genetic testing, revealing a 46 XY karyotype and an as of yet unprecedented androgen receptor mutation. The type of the mutation was a single-base exchange - the substitution from cytosine to thymine in chromosome X:66942710 position (referred to human reference genome GRCh37), which has resulted in an amino acid changes from leucine (CTT) to phenyloalanine (TTT) in ligand-binding domain.

Influence of hypoxia prevailing in post-infarction heart on proangiogenic gene expression and biological features of human myoblast cells applied as a pro-regenerative therapeutic tool

Cardiovascular diseases along with MI (myocardial infarction) lead to regional ischaemia and hypoxic conditions, which prevail after infarction. Diminished O₂ saturation which is related to elevated level of hypoxia inducible factor 1 (HIF-1) transcription factor, may switch the expression of many genes. To maximize effect of therapies proposed by regenerative medicine, it is essential to verify (within different time points after MI) the expression of proangiogenic genes and their receptors that are regulated, along with the expression of HIF-1α. We demonstrated a connection between the expression of Hif-1α (in murine post infarcted heart model) and the proangiogenic genes Vegf-a; and Plgf and their receptors during myocardial hypoxia. The innovative part of the study required establishment of the most accurate in vitro O₂ level corresponding to the hypoxia level prevailing in myocardium after MI. We determined the influence of hypoxia on the biology of human myoblasts in in vitro oxygen conditions (3%), corresponding to those prevailing in the heart after an infarction using a murine model. We also tested myoblasts that were genetically modified with VEGF-A/FGF-4 and PlGF under hypoxic conditions and compared their characteristics with cells cultured under normoxia and hyperoxia (standard in vitro conditions) with respect to myogenic gene expression, cell proliferation, fusion potential and proangiogenic function. The examination of genetically modified myoblasts under optimized in vitro hypoxia conditions led to the conclusion that hypoxia did not negatively influence the biological functions of the myoblasts, such as cell proliferation and/or proangiogenic characteristics. These results support the expected increased proregenerative effects of such genetically modified human myoblasts.

The impact of sedentary work on sperm nuclear DNA integrity

INTRODUCTION

Contemporary professional jobs that often enforce a sedentary lifestyle and are frequently associated with testicular overheat, deserve special attention with respect to male fertility potential. Interestingly, the harmful effect of testicular heat stress on sperm characteristics including nuclear DNA integrity was well characterized; however, the influence of sedentary work on sperm chromatin has not yet been documented. Therefore, our research was designed to examine the potential effects of sedentary work not only on conventional semen features but also on sperm nuclear DNA status.

MATERIALS AND METHODS

The study was carried out on ejaculated sperm cells obtained from men who spent ≥ 50% of their time at work (≥ 17.5 h per week) in a sedentary position (n = 152) and from men who spent < 50% of their time at work in a sedentary position (n = 102). Standard semen characteristics were assessed according to the WHO 2010 recommendations, while sperm nuclear DNA fragmentation (SDF) was evaluated using the Halosperm test.

RESULTS

There were no significant differences in the standard semen parameters between the study groups. The groups differed only in SDF parameter. The men who spent at least 50% of their work time in a sedentary position had a higher proportion of SDF than the men who spent < 50% of their time at work in a sedentary position (median value 21.00% vs. 16.50%, respectively). The incidence of low SDF levels (related to 0-15% sperm cells with abnormal DNA dispersion) was significantly lower (27.63% vs. 45.10%), the percentage of men with high SDF levels (related to > 30%) was significantly higher (30.92% vs. 16.67%) in group of men who spent at least 50% of their work time in a sedentary positon. Furthermore, these men were more than twice as likely to have not a low SDF level (OR: 0.4648) and had more than twice the risk of having a high SDF level (OR: 2.2381) than the men in less sedentary occupations.

CONCLUSIONS

Despite lack of association between sedentary work and conventional semen characteristics our study revealed detrimental effect of seated work on sperm nuclear DNA integrity. A sedentary job doubled the risk of high levels of sperm DNA damage. The pathomechanism could be related to testicular heat stress resulting in sperm chromatin remodelling failure during spermiogenesis. Therefore, it seems reasonable to simultaneously carry out routine seminological analyses and tests assessing sperm chromatin status while diagnosing male infertility.

Chromosome (re)positioning in spermatozoa of fathers and sons - carriers of reciprocal chromosome translocation (RCT)

Background

Non-random chromosome positioning has been observed in the nuclei of several different tissue types, including human spermatozoa. The nuclear arrangement of chromosomes can be altered in men with decreased semen parameters or increased DNA fragmentation and in males with chromosomal numerical or structural aberrations. An aim of this study was to determine whether and how the positioning of nine chromosome centromeres was (re)arranged in the spermatozoa of fathers and sons – carriers of the same reciprocal chromosome translocation (RCT).

Methods

Fluorescence in situ hybridization (FISH) was applied to analyse the positioning of sperm chromosomes in a group of 13 carriers of 11 RCTs, including two familial RCT cases: t(4;5) and t(7;10), followed by analysis of eight control individuals. Additionally, sperm chromatin integrity was evaluated using TUNEL and Aniline Blue techniques.

Results

In the analysed familial RCT cases, repositioning of the chromosomes occurred in a similar way when compared to the data generated in healthy controls, even if some differences between father and son were further observed. These differences might have arisen from various statuses of sperm chromatin disintegration.

Conclusions

Nuclear topology appears as another aspect of epigenetic genomic regulation that may influence DNA functioning. We have re-documented that chromosomal positioning is defined in control males and that a particular RCT is reflected in the individual pattern of chromosomal topology. The present study examining the collected RCT group, including two familial cases, additionally showed that chromosomal factors (karyotype and hyperhaploidy) have superior effects, strongly influencing the chromosomal topology, when confronted with sperm chromatin integrity components (DNA fragmentation or chromatin deprotamination).

Electronic supplementary material

The online version of this article (10.1186/s12920-018-0470-7) contains supplementary material, which is available to authorized users.

SPIN1 is a proto-oncogene and SPIN3 is a tumor suppressor in human seminoma

SPIN1 is necessary for normal meiotic progression in mammals. It is overexpressed in human ovarian cancers and some cancer cell lines. Here, we examined the functional significance and regulation of SPIN1 and SPIN3 in the TCam-2 human seminoma cell line. We found that while SPIN1 overexpression reduced apoptosis in these cells, SPIN3 overexpression induced it. Similarly, SPIN1 upregulated and SPIN3 downregulated CYCD1, which is a downstream target of the PI3K/AKT pathway and contributes to apoptosis resistance in cancer cell lines. It appears that SPIN1 is pro-oncogenic and SPIN3 acts as a tumor suppressor in TCam-2 cells. To our knowledge, this is the first report of SPIN3 tumor suppressor activity. However, both SPIN1 and SPIN3 stimulated cell cycle progression. In addition, using luciferase reporters carrying SPIN1 or SPIN3 mRNA 3′UTRs, we found that PUM1 and PUM2 targeted and repressed SPINs. We also found that PUM1 itself strongly stimulated apoptosis and moderately slowed cell cycle progression in TCam-2 cells, suggesting that PUM1, like SPIN3, is a tumor suppressor. Our findings suggest that acting, at least in part, through SPIN1 and SPIN3, PUM proteins contribute to a mechanism promoting normal human male germ cell apoptotic status and thus preventing cancer.

The impact of in vitro cell culture duration on the maturation of human cardiomyocytes derived from induced pluripotent stem cells of myogenic origin

Ischemic heart disease, also known as coronary artery disease (CAD), poses a challenge for regenerative medicine. iPSC technology might lead to a breakthrough due to the possibility of directed cell differentiation delivering a new powerful source of human autologous cardiomyocytes. One of the factors supporting proper cell maturation is in vitro culture duration. In this study, primary human skeletal muscle myoblasts were selected as a myogenic cell type reservoir for genetic iPSC reprogramming. Skeletal muscle myoblasts have similar ontogeny embryogenetic pathways (myoblasts vs. cardiomyocytes), and thus, a greater chance of myocardial development might be expected, with maintenance of acquired myogenic cardiac cell characteristics, from the differentiation process when iPSCs of myoblastoid origin are obtained. Analyses of cell morphological and structural changes, gene expression (cardiac markers), and functional tests (intracellular calcium transients) performed at two in vitro culture time points spanning the early stages of cardiac development (day 20 versus 40 of cell in vitro culture) confirmed the ability of the obtained myogenic cells to acquire adult features of differentiated cardiomyocytes. Prolonged 40-day iPSC-derived cardiomyocytes (iPSC-CMs) revealed progressive cellular hypertrophy; a better-developed contractile apparatus; expression of marker genes similar to human myocardial ventricular cells, including a statistically significant CX43 increase, an MHC isoform switch, and a troponin I isoform transition; more efficient intercellular calcium handling; and a stronger response to β-adrenergic stimulation.

Perspective in optimization of stem cell therapies for heart regeneration

There is a variety of mechanisms(s) factor(s) that may influence stem cell therapies for heart regeneration. Among the best candidates for stem cell source are: mesenchymal stem cells (also those isolated from adipose tissue), cardiac cell progenitors (CPC) and descendants of iPSC cells. iPSC/s can be potentially beneficial although their pluripotent induction has been still in question due to: low propagation efficacy, danger of genomic integration/instability, biological risk of current vector system teratoma formation etc. which have been discussed in this review. Optimization protocols are required in order to enhance stem cells resistance to pathological conditions that they may encounter in pathological organ and to increase their retention. Combination between gene transfer and stem cell therapy is now more often used in pre-clinical studies with the prospect of subsequent clinical trials. Complementary substances have been contemplated to support stem cell viability (mainly anti-inflammatory and anti- apoptotic agents), which have been tested in animal models with promising results. Integration of nanotechnology both for efficient stem cell imaging as well as with the aim to provide cell supporting scaffolds seem to be inevitable for further development of cellular therapies. The whole organ (heart) reconstruction as well as biodegradable scaffolds and scaffold-free cell sheets have been also outlined.

Application of stem cells in dentistry for bone regeneration

Stem cells constitute a non-specialised cell pool able for proliferation, self-renewal and differentiation into progeny constantly replacing used up tissue and/or organ fragments. They have been observed to be present in many tissue reservoirs, including stomatognathic system. Oral cavity seems to be a particularly attractive stem cells' source as these cells are richly present and easily accessible in dental and periodontal tissues and they can be used for therapeutic purposes. Their application is also morally and ethically non-controversial. Bone tissue structure restoration together with restoring its weight-bearing and nutritive function depend on the proper function of stem cells supported with other techniques including tissue engineering. Traditionally, bone regeneration means bone restoration supported by newly formed bones supplied by stem cells of tissue reservoir. It may be also indispensable to create a scaffold which may support the bone formation facilitating the transportation of cells and cell stimulating molecules involving both the matrix and bone-forming cells. The regenerative potential of stem cells present in oral cavity can be used, for instance, to restore maxillary and mandibular bones. The bones support natural teeth or prostheses and regress as soon as at least the one tooth is lost or extracted. Bone mass loss makes it difficult to conduct effective dental treatment and reduces the chances of obtaining positive, long-lasting therapeutic effects. It seems that modern and innovative therapies based on stem cells application may bring spectacular effects especially in patients in whom routine medical activities did not lead to satisfactory results.

Safety, feasibility and effectiveness of first in-human administration of muscle-derived stem/progenitor cells modified with connexin-43 gene for treatment of advanced chronic heart failure

AIMS

To assess the safety and efficacy of transendocardial delivery of muscle-derived stem/progenitor cells with connexin-43 overexpression (Cx-43-MDS/PC) in advanced heart failure (HF).

METHODS AND RESULTS

Thirteen subjects with advanced HF, New York Heart Association (NYHA) class II-III were enrolled and treated with targeted injection of Cx-43-MDS/PCs and then monitored for at least 6 months. Overexpression of Cx43 (Cx43+) was significantly higher in all but one subject (Cx43-). Injection of MDS/PCs was associated with significant improvement of exercise capacity: NYHA (3 ± 0 vs. 1.8 ± 0.7, P = 0.003), exercise duration (388.69 ± 141.83 s vs. 462.08 ± 176.69 s, P = 0.025), peak oxygen consumption (14.38 ± 3.97 vs. 15.83 ± 3.74 ml/kg.min, P = 0.022) and oxygen pulse (10.58 ± 2.89 vs. 18.88 ± 22.63 mLO₂ /heart rate, P = 0.012). Levels of BNP, left ventricular (LV) ejection fraction and LV end-diastolic volumes tended to improve. There was a significant improvement of the mean unipolar voltage amplitudes measured for the injected segments and the entire left ventricle (9.62 ± 2.64 vs. 11.62 ± 3.50 mV, P = 0.014 and 8.83 ± 2.80 vs. 10.22 ± 3.41 mV, P = 0.041, respectively). No deaths were documented, Cx43+ (n = 12) subjects presented no significant ventricular arrhythmia; one Cx43- subject suffered from ventricular tachycardia (successfully treated with amiodarone).

CONCLUSIONS

Injection of Cx-43-MDS/PCs in patients with severe HF led to significant improvement in exercise capacity and myocardial viability of the injected segments while inducing no significant ventricular arrhythmia. This may arise from improved electrical coupling of the injected cells and injured myocardium and thus better in-situ mechanical cooperation of both cell types. Therefore, further clinical studies with Cx43+ MDS/PCs are warranted.

The oral cavity - potential source of stem cells

The purpose of this review is to present the current knowledge regarding the hierarchy of stem cells originating from the oral cavity, which could have a potential value when applied to regenerative stomatology. It must be particularly emphasized that the heterogenous nature of its biology and function within oral compartment may predispose them to different types of applications. Stem cells can be perceived as immature, primitive and unspecialized types of cells with the ability to proliferate, self-renew and differentiate into specialized progeny according to the compartmental signaling. Their presence in tissue reservoirs was already discovered in many organs and tissues as well as in the stomatognathic system. The oral cavity appears to be an exceptionally attractive site to acquire stem cells. The common presence and easy access to these cells in dental and peridental tissues provides a real chance to apply them for therapeutic purposes. Such an opportunity would also be neutral to bioethical and moral issues, assuming autologous stem cells employment. Many authors suspect that stem cells have epigenetic memory, so some of their features can be inherited through generations. They are not connected, however, with DNA sequence modifications. It is, therefore, justified to apply the cells, which have the oral cavity as their natural reservoir, in interventions associated with tissue engineering within the stomatognathic system. An increasing number of clinical trials, among which the number of randomized studies with large group of patients is progressively carried out, allows for a prediction that shortly therapeutic methods based on stem cells of dental origin may be implemented to the routine repertoire of clinical practice.

HBcAg produced in transgenic tobacco triggers Th1 and Th2 response when intramuscularly delivered

Hepatitis B core Antigen (HBcAg) assembled into Capsid-Like Particles (CLPs) is investigated as a therapeutic vaccine in treatment of chronic hepatitis B (CHB) and in diagnostic tests or as a carrier for various epitopes. While the expression of HBcAg has been thoroughly clarified in E. coli and yeast, it has also been investigated in other expression systems. Stably transformed tobacco expressed HBcAg at a level of 110-250µg/g fresh weight, therefore in view of its large leaf biomass it offers a production platform comparable with transient expression systems regarding the final yield of HBcAg. Several extraction and purification methods were tested and finally the antigen was purified up to 43% using sucrose density gradient centrifugation. The purified HBcAg retained its antigenicity, as confirmed by ELISA and western blot, while maintaining its CLP-structure as observed in TEM. In mice HBcAg intramuscularly delivered at 2×10µg triggered a significant response (serum anti-HBc titre around 150,000), being statistically equivalent to that induced by the reference antigen. Among anti-HBc IgG isotypes, IgG2a and then IgG1 were increasing during immune response. However IgG2b and IgG3 were also induced, especially in mice immunised with the plant-derived antigen. Analysis of the isotype profile indicates mainly Th1 polarisation, but completed with Th2 response. Obtained results indicate a considerable potential of plant-derived HBcAg as a therapeutic vaccine, since a mixed immune response with a stronger Th1 component is particularly required for treatment of CHB.

Biological and Pro-Angiogenic Properties of Genetically Modified Human Primary Myoblasts Overexpressing Placental Growth Factor in In Vitro and In Vivo Studies

Cardiovascular diseases are a growing problem in developing countries; therefore, there is an ongoing intensive search for new approaches to treat these disorders. Currently, cellular therapies are focused on healing the damaged heart by implanting stem cells modified with pro-angiogenic factors. This approach ensures that the introduced cells are capable of fulfilling the complex requirements of the environment, including the replacement of the post-infarction scar with cells that are able to contract and promote the formation of new blood vessels that can supply the ischaemic region with nutrients and oxygen. This study focused on the genetic modification of human skeletal muscle cells (SkMCs). We chose myoblast cells due to their close biological resemblance to cardiomyocytes and the placental growth factor (PlGF) gene due to its pro-angiogenic potential. In our in vitro studies, we transfected SkMCs with the PlGF gene using electroporation, which has previously been proven to be efficient and generate robust overexpression of the PlGF gene and elevate PlGF protein secretion. Moreover, the functionality of the secreted pro-angiogenic proteins was confirmed using an in vitro capillary development assay. We have also examined the influence of PlGF overexpression on VEGF-A and VEGF-B, which are well-known factors described in the literature as the most potent activators of blood vessel formation. We were able to confirm the overexpression of VEGF-A in myoblasts transfected with the PlGF gene. The results obtained in this study were further verified in an animal model. These data were able to confirm the potential therapeutic effects of the applied treatments.

Global methylation status of sperm DNA in carriers of chromosome structural aberrations

Male infertility might be clearly associated with aberrant DNA methylation patterns in human spermatozoa. An association between oxidative stress and the global methylation status of the sperm genome has also been suggested. The aim of the present study was to determine whether the global sperm DNA methylation status was affected in the spermatozoa of carriers of chromosome structural aberrations. The relationships between the 5-methylcytosine (m⁵C) levels in spermatozoa and chromatin integrity status were evaluated. The study patients comprised male carriers of chromosome structural aberrations with reproductive failure (n = 24), and the controls comprised normozoospermic sperm volunteers (n = 23). The global m⁵C level was measured using thin-layer chromatography (TLC) and immunofluorescence (IF) techniques. The sperm chromatin integrity was assessed using aniline blue (AB) staining and TUNEL assay. The mean m⁵C levels were similar between the investigated chromosome structural aberrations carriers (P) and controls (K). However, sperm chromatin integrity tests revealed significantly higher values in chromosomal rearrangement carriers than in controls (P < 0.05). Although the potential relationship between sperm chromatin integrity status and sperm DNA fragmentation and the m⁵C level juxtaposed in both analyzed groups (P vs K) was represented in a clearly opposite manner, the low chromatin integrity might be associated with the high hypomethylation status of the sperm DNA observed in carriers of chromosome structural aberrations.

In vitro culture of primary human myoblasts by using the dextran microcarriers Cytodex3®

INTRODUCTION

Primary cells in vitro culture scale-up is a crucial issue in cell-based tissue and organ regeneration therapy. Reducing costs and space occupied by the cells cultured in vitro has been an important target. Cells cultured in vitro with the use of bioreactor with dextran microcarriers (Cytodex®) have potentially a chance to meet many of the cell therapy requirements.

MATERIAL AND METHODS

We used collagen-coated carriers (Cytodex3®) and a spinner flask bioreactor to develop environment suitable for human myoblast proliferation. In parallel, standard adherent in vitro culture conditions for myoblasts propagation (T-flask) were conducted. Cell cycle characterization, senescence, myogenic gene ex-pression and cell apoptosis were evaluated in order to find differences between two culture systems under study.

RESULTS

The number of cells obtained in bioreactor per 106 of starting cells population was approximately ten times lower in comparison with T-flask culture system. The microcarriers cultured adult myoblasts in compari-son with the regular T-flask culture showed faster and more advanced replicative aging and lower proliferative potential. Moreover, the percentage of the cells that entailed an irreversible cell arrest (G0 phase) was also significantly (p < 0.0001) increased.

CONCLUSIONS

Our results suggest that population of primary human myoblasts obtained from adult individuals and propagated on dextran microcarriers did not meet the requirements of the regenerative medicine regarding quantity and quality of the cells obtained. Nonetheless, further optimization of the cell scaling up process including both microcarriers and/or bioreactor program is still an important option.

Techniques for the induction of human pluripotent stem cell differentiation towards cardiomyocytes

The derivation of pluripotent stem cells from human embryos and the generation of induced pluripotent stem cells (iPSCs) from somatic cells opened a new chapter in studies on the regeneration of the post-infarction heart and regenerative medicine as a whole. Thus, protocols for obtaining iPSCs were enthusiastically adopted and widely used for further experiments on cardiac differentiation. iPSC-mediated cardiomyocytes (iPSC-CMs) under in vitro culture conditions are generated by simulating natural cardiomyogenesis and involve the wingless-type mouse mammary tumour virus integration site family (WNT), transforming growth factor beta (TGF-β) and fibroblast growth factor (FGF) signalling pathways. New strategies have been proposed to take advantage of small chemical molecules, organic compounds and even electric or mechanical stimulation. There are three main approaches to support cardiac commitment in vitro: embryoid bodis (EBs), monolayer in vitro cultures and inductive co-cultures with visceral endoderm-like (END2) cells. In EB technique initial uniform size of pluripotent stem cell (PSC) colonies has a pivotal significance. Hence, some methods were designed to support cells aggregation. Another well-suited procedure is based on culturing cells in monolayer conditions in order to improve accessibility of growth factors and nutrients. Other distinct tactics are using visceral endoderm-like cells to culture them with PSCs due to secretion of procardiac cytokines. Finally, the appropriate purification of the obtained cardiomyocytes is required prior to their administration to a patient under the prospective cellular therapy strategy. This goal can be achieved using non-genetic methods, such as the application of surface markers and fluorescent dyes. Copyright © 2016 John Wiley & Sons, Ltd.

Meiotic and pedigree segregation analyses in carriers of t(4;8)(p16;p23.1) differing in localization of breakpoint positions at 4p subband 4p16.3 and 4p16.1

PURPOSE

The purpose of this study was to compare meiotic segregation in sperm cells from two carriers with t(4;8)(p16;p23.1) reciprocal chromosome translocations (RCTs), differing in localization of the breakpoint positions at the 4p subband-namely, 4p16.3 (carrier 1) and 4p16.1 (carrier 2)-and to compare data of the pedigree analyses performed by direct method.

METHODS

Three-color fluorescent in situ hybridization (FISH) on sperm cells and FISH mapping for the evaluation of the breakpoint positions, data from pedigrees, and direct segregation analysis of the pedigrees were performed.

RESULTS

Similar proportions of normal/balanced and unbalanced sperm cells were found in both carriers. The most common was an alternate type of segregation (about 52 % and about 48 %, respectively). Unbalanced adjacent I and adjacent II karyotypes were found in similar proportions about 15 %. The direct segregation analysis (following Stengel-Rutkowski) of the pedigree of carriers of t(4;8)(p16.1;p23.1) was performed and results were compared with the data of the pedigree segregation analysis obtained earlier through the indirect method. The probability of live-born progeny with unbalanced karyotype for carriers of t(4;8)(p16.1;p23.1) was moderately high at 18.8 %-comparable to the value obtained using the indirect method for the same carriership, which was 12 %. This was, however, markedly lower than the value of 41.2 % obtained through the pedigree segregation indirect analysis estimated for carriers of t(4;8)(p16.3;p23.1), perhaps due to the unique composition of genes present within the 4p16.1-4p 16.3 region.

CONCLUSIONS

Revealed differences in pedigree segregation analysis did not correspond to the very similar profile of meiotic segregation patterns presented by carrier 1 and carrier 2. Most probably, such discordances may be due to differences in embryo survival rates arising from different genetic backgrounds.

Genetic dosage and position effect of small supernumerary marker chromosome (sSMC) in human sperm nuclei in infertile male patient

Chromosomes occupy specific distinct areas in the nucleus of the sperm cell that may be altered in males with disrupted spermatogenesis. Here, we present alterations in the positioning of the human chromosomes 15, 18, X and Y between spermatozoa with the small supernumerary marker chromosome (sSMC; sSMC⁺) and spermatozoa with normal chromosome complement (sSMC⁻), for the first time described in the same ejaculate of an infertile, phenotypically normal male patient. Using classical and confocal fluorescent microscopy, the nuclear colocalization of chromosomes 15 and sSMC was analyzed. The molecular cytogenetic characteristics of sSMC delineated the karyotype as 47,XY,+der(15)(pter->p11.2::q11.1->q11.2::p11.2->pter)mat. Analysis of meiotic segregation showed a 1:1 ratio of sSMC⁺ to sSMC⁻ spermatozoa, while evaluation of sperm aneuploidy status indicated an increased level of chromosome 13, 18, 21 and 22 disomy, up to 7 × (2.7 − 15.1). Sperm chromatin integrity assessment did not reveal any increase in deprotamination in the patient’s sperm chromatin. Importantly, we found significant repositioning of chromosomes X and Y towards the nuclear periphery, where both chromosomes were localized in close proximity to the sSMC. This suggests the possible influence of sSMC/XY colocalization on meiotic chromosome division, resulting in abnormal chromosome segregation, and leading to male infertility in the patient.