Sandra Sequeira Laurentino

Sandra Sequeira Laurentino
University of Münster | WWU · Center of Reproductive Medicine and Andrology

PhD

About

28
Publications
3,649
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
550
Citations
Citations since 2016
18 Research Items
376 Citations
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
Introduction
I'm a group leader at the Center of Reproductive Medicine and Andrology at the University of Münster, Germany, working on reproductive biology with an emphasys on regulation of gene expression in the male germline and reproductive ageing.
Additional affiliations
January 2007 - November 2011
Universidade da Beira Interior
Position
  • PhD Student

Publications

Publications (28)
Article
Full-text available
Background Several studies have reported an association between male infertility and aberrant sperm DNA methylation patterns, in particular in imprinted genes. In a recent investigation based on whole methylome and deep bisulfite sequencing, we have not found any evidence for such an association, but have demonstrated that somatic DNA contamination...
Article
Full-text available
Despite the high incidence of male infertility, only 30% of infertile men receive a causative diagnosis. To explore the regulatory mechanisms governing human germ cell function in normal and impaired spermatogenesis (crypto), we performed single-cell RNA sequencing (>30,000 cells). We find major alterations in the crypto spermatogonial compartment...
Article
Study question Do DNA methylation changes occur in testicular germ cells (TGCs) from patients with impaired spermatogenesis? Summary answer TGCs from men with cryptozoospermia exhibit altered DNA methylation levels at several genomic regions, many of which are associated with genes involved in spermatogenesis. What is known already In the last 15...
Preprint
Full-text available
Despite the high incidence of male infertility, about 70% of infertile men do not receive a causative diagnosis. To gain insights into the regulatory mechanisms governing human germ cell function in normal and impaired spermatogenesis (cryptozoospermic patients, crypto), we combined single cell RNA sequencing (>30.000 cells), proteome, and histomor...
Article
Delayed family planning and increased parental age increases the risk for infertility and impaired offspring health. While the impact of ageing on oogenesis is well studied, on spermatogenesis this is less understood. Assessing ageing effects on the male germline presents the challenge of differentiating between the effects of ageing-associated mor...
Article
Full-text available
Background: In the past 15 years, numerous studies have described aberrant DNA methylation of imprinted genes (e.g. MEST and H19) in sperm of oligozoospermic men, but the prevalence and genomic extent of abnormal methylation patterns have remained unknown. Results: Using deep bisulfite sequencing (DBS), we screened swim-up sperm samples from 40...
Article
Full-text available
Life-long sperm production leads to the assumption that male fecundity remains unchanged throughout life. However, recently it was shown that paternal age has profound consequences for male fertility and offspring health. Paternal age effects are caused by an accumulation of germ cell mutations over time, causing severe congenital diseases. Apart f...
Article
Full-text available
Objective: To delineate the role of gonadotropins in male androgen biosynthesis pathways DESIGN: Case-control study PATIENTS AND MEASUREMENTS: 25 males with congenital hypogonadotropic hypogonadism (CHH) underwent hCG/rFSH and testosterone treatment sequentially. Serum steroid hormone profiles (testosterone precursors and metabolites) on both repl...
Article
Molecular aging markers provide the opportunity for biological age determination in humans and to study factors, such as genetic determinants, affecting the ageing process. In males with Klinefelter syndrome (KS, non-mosaic karyotype 47, XXY), which is the most common sex chromosome aneuploidy, age-related morbidity and mortality are increased, and...
Article
Full-text available
Background: Analysing whole genome bisulfite sequencing datasets is a data-intensive task that requires comprehensive and reproducible workflows to generate valid results. While many algorithms have been developed for tasks such as alignment, comprehensive end-to-end pipelines are still sparse. Furthermore, previous pipelines lack features or show...
Preprint
Full-text available
Background In the past 15 years, numerous studies have described aberrant DNA methylation of imprinted genes (e.g. MEST and H19 ) in sperm of infertile patients, but the prevalence and genomic extent of abnormal methylation patterns have remained unknown. Results Using deep bisulfite sequencing (DBS), we screened swim-up sperm samples from 40 norm...
Preprint
Full-text available
Background Analysing whole genome bisulfite sequencing datasets is a data-intensive task that requires comprehensive and reproducible workflows to generate valid results. While many algorithms have been developed for tasks such as alignment, comprehensive end-to-end pipelines are still sparse. Furthermore, previous pipelines lack features or show t...
Preprint
Full-text available
Children of older fathers have higher risk for certain diseases. Nevertheless, how ageing specifically affects male germ cells is so far not completely understood. In a cohort of 197 healthy men (18-84 years), we found that semen and reproductive parameters remained normal over six decades. Along with an age-dependent increase in telomere length in...
Article
Full-text available
Background: The most common sex chromosomal aneuploidy in males is Klinefelter syndrome, which is characterized by at least one supernumerary X chromosome. While these men have long been considered infertile, focal spermatogenesis can be observed in some patients, and sperm can be surgically retrieved and used for artificial reproductive technique...
Article
Full-text available
The timing of de novo DNA methylation in male germ cells during human testicular development is yet unsolved. Apart from that, the stability of established imprinting patterns in vitro is controversially discussed. This study aimed at determining the timing of DNA de novo methylation and at assessing the stability of the methylation status in vitro...
Article
The X-linked reproductive homeobox (RHOX) gene cluster encodes transcription factors preferentially expressed in reproductive tissues. This gene cluster has important roles in male fertility based on phenotypic defects of Rhox-mutant mice and the finding that aberrant RHOX promoter methylation is strongly associated with abnormal human sperm parame...
Article
The influence of epigenetic modifications on reproduction and on the function of male germ cells has been thoroughly demonstrated. In particular, aberrant DNA methylation levels in sperm have been associated with abnormal sperm parameters, lower fertilization rates and impaired embryo development. Recent reports have indicated that human sperm migh...
Article
Full-text available
Imprinted genes are expressed either from the paternal or the maternal allele, because the other allele has been silenced in the mother's or father's germline. Imprints are characterized by DNA methylation at CpG sites. Recently, abnormal sperm parameters and male infertility have been linked to aberrant methylation patterns of imprinted genes in s...
Chapter
Full-text available
Androgens are the key elements in the control of male reproductive function, exerting biological effects by interaction with their cognate intracellular receptors. The androgen receptor (AR), a member of the nuclear receptor superfamily, acts as a transcription factor modulating the gene-expression network in target tissues. Structurally, AR is com...
Article
Full-text available
The androgen receptor (AR) is a ligand-activated transcription factor member of the nuclear receptor superfamily. The existence of alternatively spliced variants is well recognised for several members of this superfamily, most of them having functional importance. For example, several testicular oestrogen receptor variants have been suggested to pl...
Article
The androgen receptor (AR) is a ligand-activated transcription factor member of the nuclear receptor superfamily. The existence of alternatively spliced variants is well recognised for several members of this superfamily, most of them having functional importance. For example, several testicular oestrogen receptor variants have been suggested to pl...
Article
Full-text available
Regucalcin (RGN) is a calcium (Ca2+)-binding protein which plays an important role in the regulation of Ca2+ homeostasis and has been shown to catalyse an important step in l-ascorbic acid biosynthesis. It is encoded by an X-linked gene and differs from other Ca2+-binding proteins by lacking the typical EF-hand Ca2+-binding domain. RGN controls int...
Article
Sertoli cells metabolize glucose producing lactate for developing germ cells. As insulin regulates glucose uptake and its disturbance/insensitivity is associated with diabetes mellitus, we aimed to determine the effect of insulin deprivation in human Sertoli cell (hSC) metabolism and metabolism-associated gene expression. hSC-enriched primary cultu...
Article
To study the expression and localization of Aven in rat and human testis from azoospermic patients with different etiologies and its regulation by estrogens. Experimental study. University research center and private IVF clinic. Six men with obstructive azoospermia, five with hypospermatogenesis, and six with Sertoli cell-only syndrome; male Wistar...
Article
Full-text available
Regucalcin (RGN) is a calcium (Ca(2)(+))-binding protein which regulates intracellular Ca(2)(+) homeostasis by modulating the activity of enzymes regulating Ca(2)(+) concentration and enhancing Ca(2)(+)-pumping activity. Several studies have described the pivotal role of proper Ca(2)(+) homeostasis regulation to spermatogenesis and male fertility....
Article
Full-text available
Currently, clinical and experimental evidence point to an essential role of estrogens and estrogen receptors in male fertility. The expression of estrogen receptor α (ERα) and β (ERβ) in human testis has been described. However, some studies were unable to detect ERα, while others report the expression of both isoforms, with ERβ presenting a wide d...
Article
Full-text available
Currently, clinical and experimental evidence point to an essential role of estrogens and estrogen receptors in male fertility. The expression of estrogen receptor alpha (ERalpha) and beta (ERbeta) in human testis has been described. However, some studies were unable to detect ERalpha, while others report the expression of both isoforms, with ERbet...

Network

Cited By

Projects

Project (1)
Project
Link to CRU homepage: www.male-germ-cells.de In the course of this CRU, we will cut in half the fraction of currently ~70% unexplained cases of male infertility by assigning a specific genetic di agnosis to additional 30-40% of men compared with the current routine diagnostics. To this end, we will introduce novel diagnostic procedures (e.g. targeted sequencing of the prioritised genes) into clinical routine. This will allow for more precise risk estimates, better counselling of coupl es, and evidence-based treatment decisions. Ultimately, elucidating the causes underlying male infertility and corresponding phenotypes will pave the road for novel, personalised treatment reg imens improving patient care and offspring health. Beyond the course of the CRU, further major contributions to the field of Andrology and Reproductive Genetics are envisaged.