Microbiota and Human Reproduction: The Case of Male Infertility

The increasing interest in metagenomics is enhancing our knowledge regarding the composition and role of the microbiota in human physiology and pathology. Indeed, microbes have been reported to play a role in several diseases, including infertility. In particular, the male seminal microbiota has been suggested as an important factor able to influence couple’s health and pregnancy outcomes, as well as offspring health. Nevertheless, few studies have been carried out to date to deeper investigate semen microbiome origins and functions, and its correlations with the partner’s reproductive tract microbiome. Here, we report the state of the art regarding the male reproductive system microbiome and its alterations in infertility

Microbiota and Human Reproduction: The Case of Female Infertility

During the last decade, the availability of next-generation sequencing-based approaches has revealed the presence of microbial communities in almost all the human body, including the reproductive tract. As for other body sites, this resident microbiota has been involved in the maintenance of a healthy status. As a consequence, alterations due to internal or external factors may lead to microbial dysbiosis and to the development of pathologies. Female reproductive microbiota has also been suggested to affect infertility, and it may play a key role in the success of assisted reproductive technologies, such as embryo implantation and pregnancy care. While the vaginal microbiota is well described, the uterine microbiota is underexplored. This could be due to technical issues, as the uterus is a low biomass environment. Here, we review the state of the art regarding the role of the female reproductive system microbiota in women's health and human reproduction, highlighting its contribution to infertility

Endosomal trafficking and related genetic underpinnings as a hub in Alzheimer's disease

Genetic studies support the amyloid cascade as the leading hypothesis for the pathogenesis of Alzheimer's disease (AD). Although significant efforts have been made in untangling the amyloid and other pathological events in AD, ongoing interventions for AD have not been revealed efficacious for slowing down disease progression. Recent advances in the field of genetics have shed light on the etiology of AD, identifying numerous risk genes associated with late-onset AD, including genes related to intracellular endosomal trafficking. Some of the bases for the development of AD may be explained by the recently emerging AD genetic "hubs," which include the processing pathway of amyloid precursor protein and the endocytic pathway. The endosomal genetic hub may represent a common pathway through which many pathological effects can be mediated and novel, alternative biological targets could be identified for therapeutic interventions. The aim of this review is to focus on the genetic and biological aspects of the endosomal compartments related to AD progression. We report recent studies which describe how changes in endosomal genetics impact on functional events, such as the amyloidogenic and non-amyloidogenic processing, degradative pathways, and the importance of receptors related to endocytic trafficking, including the 37/67 kDa laminin-1 receptor ribosomal protein SA, and their implications for neurodegenerative diseases

Current Updates on Expanded Carrier Screening: New Insights in the Omics Era

Genetic carrier screening has been successfully used over the last decades to identify individuals at risk of transmitting specific DNA variants to their newborns, thus having an affected child. Traditional testing has been offered based on familial and/or ethnic backgrounds. The development of high-throughput technologies, such as next-generations sequencing, able to allow the study of large genomic regions in a time and cost-affordable way, has moved carrier screening toward a more comprehensive and extensive approach, i.e., expanded carrier screening (ECS). ECS simultaneously analyses several disease-related genes and better estimates individuals’ carrier status. Indeed, it is not influenced by ethnicity and is not limited to a subset of mutations that may arise from poor information in some populations. Moreover, if couples carry out ECS before conceiving a baby, it allows them to obtain a complete estimation of their genetic risk and the possibility to make an informed decision regarding their reproductive life. Despite these advantages, some weakness still exists regarding, for example, the number of genes and the kind of diseases to be analyzed and the interpretation and communication of the obtained results. Once these points are fixed, it is expectable that ECS will become an ever more frequent practice in clinical settings

Metagenomics Reveals Specific Microbial Features in Males with Semen Alterations

Infertility incidence is rising worldwide, with male infertility accounting for about 50% of cases. To date, several factors have been associated with male infertility; in particular, it has been suggested that semen microbiota may play a role. Here, we report the NGS-based analyses of 20 semen samples collected from men with (Case) and without (Control) semen alterations. Genomic DNA was extracted from each collected sample, and a specific PCR was carried out to amplify the V4-V6 regions of the 16S rRNA. Sequence reactions were carried out on the MiSeq and analyzed by specific bioinformatic tools. We found a reduced richness and evenness in the Case versus the Control group. Moreover, specific genera, the Mannheimia, the Escherichia_Shigella, and the Varibaculum, were significantly increased in the Case compared to the Control group. Finally, we highlighted a correlation between the microbial profile and semen hyperviscosity. Even if further studies are required on larger groups of subjects to confirm these findings and explore mechanistic hypotheses, our results confirm the correlation between semen features and seminal microbiota. These data, in turn, may open the way to the possible use of semen microbiota as an attractive target for developing novel strategies for infertility management

Gut Microbiome and Mycobiome Alterations in an In Vivo Model of Alzheimer’s Disease

Gut microbiota has emerged as an important key regulator of health and disease status. Indeed, gut microbial dysbiosis has been identified in an increasing number of diseases, including neurodegenerative disorders. Accordingly, microbial alterations have been reported also in Alzheimer’s disease (AD), suggesting possible pathogenetic mechanisms contributing to the development of specific AD hallmarks and exacerbating metabolic alterations and neuroinflammation. The identification of these mechanisms is crucial to develop novel, targeted therapies and identify potential biomarkers for diagnostic purposes. Thus, the possibility to have AD in vivo models to study this microbial ecosystem represents a great opportunity for translational applications. Here, we characterized both gut microbiome and mycobiome of 3xTg-AD mice, one of the most widely used AD models, to identify specific microbial alterations with respect to the wild-type counterpart. Interestingly, we found a significant reduction of the Coprococcus and an increased abundance of Escherichia_Shigella and Barnesiella genera in the AD mice compatible with a pro-inflammatory status and the development of AD-related pathogenetic features. Moreover, the fungal Dipodascaceae family was significantly increased, thus suggesting a possible contribution to the metabolic alterations found in AD. Our data point out the strict connection between bacterial dysbiosis and AD and, even if further studies are required to clarify the underlining mechanisms, it clearly indicates the need for extensive metagenomic studies over the bacterial counterpart

The Third-Generation Sequencing Challenge: Novel Insights for the Omic Sciences

The understanding of the human genome has been greatly improved by the advent of next-generation sequencing technologies (NGS). Despite the undeniable advantages responsible for their widespread diffusion, these methods have some constraints, mainly related to short read length and the need for PCR amplification. As a consequence, long-read sequencers, called third-generation sequencing (TGS), have been developed, promising to overcome NGS. Starting from the first prototype, TGS has progressively ameliorated its chemistries by improving both read length and base-calling accuracy, as well as simultaneously reducing the costs/base. Based on these premises, TGS is showing its potential in many fields, including the analysis of difficult-to-sequence genomic regions, structural variations detection, RNA expression profiling, DNA methylation study, and metagenomic analyses. Protocol standardization and the development of easy-to-use pipelines for data analysis will enhance TGS use, also opening the way for their routine applications in diagnostic contexts

Combined aCGH and Exome Sequencing Analysis Improves Autism Spectrum Disorders Diagnosis: A Case Report

: Background and Objectives: The development and standardization of genome-wide technologies able to carry out high-resolution, genomic analyses in a cost- and time-affordable way is increasing our knowledge regarding the molecular bases of complex diseases like autism spectrum disorder (ASD). ASD is a group of heterogeneous diseases with multifactorial origins. Genetic factors seem to be involved, albeit they remain still largely unknown. Here, we report the case of a child with a clinical suspicion of ASD investigated by using such a genomic high-resolution approach. Materials and Methods: Both array comparative genomic hybridization (aCGH) and exome sequencing were carried out on the family trio. aCGH was performed using the 4 × 180 K SurePrint G3 Human CGH Microarray, while the Human All Exon V7 targeted SureSelect XT HS panel was used for exome sequencing. Results: aCGH identified a paternally inherited duplication of chromosome 7 involving the CNTNAP2 gene, while 5 potentially clinically-relevant variants were identified by exome sequencing. Conclusions: Within the identified genomic alterations, the CNTNAP2 gene duplication may be related to the patient's phenotype. Indeed, this gene has already been associated with brain development and cognitive functions, including language. The paternal origin of the alteration cannot exclude an incomplete penetrance. Moreover, other genomic factors may act as phenotype modifiers combined with CNTNAP2 gene duplication. Thus, the case reported herein strongly reinforces the need to use extensive genomic analyses to shed light on the bases of complex diseases

Evaluation of a Four-Gene Panel for Hereditary Cancer Risk Assessment

BRCA1/2 are tumor suppressor genes involved in DNA double-strand break repair. They are the most penetrant genes for hereditary breast and ovarian cancers, but pathogenic variants in these two genes can be identified only in a fraction of hereditary cases. Following the diffusion of BRCA molecular testing and the availability of specific therapeutic strategies for the management of pathogenic variant carriers, the demand for the analysis of additional predisposing genetic factors has increased. Indeed, there is accumulating evidence regarding the role of other genes, including CHEK2 and PALB2. Both of them are involved in the same molecular pathway as BRCA genes, with CHEK2 being responsible for cell cycle stopping to allow the repair of DNA double-strand breaks and PALB2 being able to interact with BRCA1 and activate BRCA2. Thus, their role as additional hereditary cancer predisposing factors is intriguing. Accordingly, guidelines for hereditary cancer risk assessment have been updated to include the criteria for additional genes testing. In this context, we validated a commercially available kit allowing for the simultaneous analysis of BRCA1, BRCA2, CHEK2 and PALB2. Forty-eight patients, already tested for BRCA mutational status, were re-analyzed in the present study. Results comparison showed that the tested method was able to correctly identify all the variants previously detected in the same patients. In particular, all single-nucleotide variants and small indels were correctly identified. Moreover, two copy number variants, included to assess the software's performance in detecting this kind of gene alteration, were also detected. Even if copy number variant estimation still requires confirmation by a molecular technique to avoid false positive results, it is able to reduce the number of patients requiring multiplex ligation probe amplification analysis, positively impacting the test's turnaround time. Finally, since the time and costs of the analysis are similar to those required just for BRCA genes, this strategy may be affordable for providing a more comprehensive test for hereditary cancer risk assessment