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Projeto de investigação
The sperm cell core genetic program - a combined clinical and basic research approach to the diagnosis of male infertility.
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A (micro)environmental perspective on the evolution of female reproductive aging
Publication . Costa, Paulo Navarro
Aging is a natural process associated with a progressive decrease of cellular and tissue function. Such age-dependent disruption of organismal homeostasis is referred to as senescence. The dynamics of the aging process vary between different organs, with the female reproductive system being the most extreme case of this heterogeneity. Indeed, the cessation of human female reproductive capacity occurs well before the end of expected lifespan. In an era when most human populations have come to benefit from substantial increases in average life expectancy, the early termination of female reproductive capacity remains an epidemiologically intriguing question and a clinically pertinent topic. In this issue of the Journal of Assisted Reproduction and Genetics, the problem of reproductive aging is comprehensively addressed under the auspices of human life history theory. To further ease our readers into the burgeoning field of evolutionary medicine, the present commentary focuses on key Darwinian concepts at the heart of the early cessation of human ovarian function.
Sex and suicide : the curious case of Toll-like receptors
Publication . Navarro-Costa, Paulo; Molaro, Antoine; Misra, Chandra Shekhar; Meiklejohn, Colin; Ellis, Peter
During in vitro fertilisation (IVF), pharmacological activation of the murine X chromosome–encoded receptor proteins Toll-like receptor (TLR) 7 and TLR8 reportedly results in male-biased litters by selectively disrupting the motility of X-bearing sperm cells. Thus—in the context of agonist treatment during IVF—these receptors act as ‘suicidal’ segregation distorters that impair their own transmission to the next generation. Such behaviour would, from an evolutionary perspective, be strongly selected against if present during natural fertilisation. Consequently, TLR7/8 biology in vivo must differ significantly from this in vitro situation to allow these genes to persist in the genome. Here, we use our current understanding of male germ cell biology and TLR function as a starting point to explore the mechanistic and evolutionary aspects of this apparent paradox.
The time is ripe for oocyte in vitro maturation
Publication . Plancha, Carlos E.; Rodrigues, Patrícia; Marques, Mónica; Almeida, Joana; Navarro-Costa, Paulo
When it comes to welcome transitions 2021 seems to have started on a promising note. From the ushering in of COVID-19 vaccination programs to a renewed appreciation of evidence-based policy in many countries progress manifested itself in swift and emphatic manners. The same can be said of the field of assisted reproduction techniques (ART) home to a recent practice committee document on oocyte in vitro maturation (IVM) [1]. In this landmark document the practice committees of the American Society for Reproductive Medicine (ASRM) the Society of Reproductive Biologists and Technologists and the Society for Assisted Reproductive Technology (SART) present a considerable (and compelling) body of published evidence supporting the conclusion that IVM should no longer be considered an experimental technique.
The emerging role of transcriptional regulation in the oocyte-to-zygote transition
Publication . Navarro-Costa, Paulo; Martinho, Rui Goncalo
Fertilization marks the beginning of a new life by converting two terminally differentiated gametes into a single totipotent zygote. Central to this transition is a complex biological program commonly referred to as oocyte activation—an umbrella term for a series of profound changes that prepare the fertilized oocyte for totipotency. These include, among others, the completion of meiosis, the formation of the two pronuclei, and the selective translation of maternal RNAs. A remarkable aspect of oocyte activation is that it occurs in the absence of transcription. Not surprisingly, most of our knowledge of this process is centered on the posttranscriptional regulation of gene expression. Yet, a recent body of evidence has brought new focus on the fundamental importance of transcriptional regulation during oogenesis as a primer for the oocyte-to-zygote transition.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
3599-PPCDT
Número da atribuição
PTDC/MEC-AND/30221/2017