Biology subjects

Court, M.

Publications and source records attributed to Court, M..

3 recordsLinked to original sources

bioRxiv2023

Sperm motility restoration in mice suffering from oligo-astheno-teratozoospermia by in vivo injection and electroporation of naked mRNA

Oligo-astheno-teratozoospermia (OAT), a recurent cause of male infertility, is the most frequent disorder of spermatogenesis with a probable genetic cause. Patients and mice bearing mutations in the ARMC2 gene have a decreased sperm concentration, and individual sperm show multiple morphological defects and a lack of motility - a canonical OAT phenotype. Intracytoplasmic sperm injection (ICSI) is required to treat such a condition but it is associated with a small increase in birth defects in comparison to pregnancies not involving assisted conception. Consequently, new targeted treatments are needed to restore fertility. Here, a combination of in vivo injection and electroporation of capped and poly-A-tailed naked mRNA is tested as a strategy to treat ARMC2-related infertility in mouse. mRNAs coding for several reporter genes are tested and the efficiency and the kinetic of expression are assessed using in vivo and in vitro 2D and 3D imaging experiments. We show that mRNA-coded reporter proteins are detected for up to 3 weeks in germ cells, making the use of mRNA possible to treat infertility. We compare these results with those obtained with a non-integrative plasmid Enhanced Episomal Vector (EEV), which induces low and transient expression in spermatogenic cells. Consequently, injection and electroporation of naked mRNA-Armc2 into the testes of Armc2-deficient males were performed and we show the presence of normal and motile sperm in the epididymis. These motile sperm were able to produce embryos by IVF and ICSI. This study demonstrates, for the first time, that mRNA electroporation can restore sperm motility and partially fertilizing ability, providing a proof-of-concept for mRNA-based strategies to correct monogenic causes of male infertility and opening new avenues for male infertility treatment.

molecular biology↗

bioRxiv2023

Oxygen loss compromises the survival and cognition of a coastal cephalopod

The ocean is undergoing deoxygenation and the spread of hypoxic areas. Ocean deoxygenation and standing levels of hypoxia are shrinking fundamental niches, particularly in coastal areas, yet documented repercussions on species development and behavior are limited. Here, we tackled the impacts of deoxygenation (7 mg O2 L-1), mild hypoxia (nocturnal 5 mg O2 L-1), and severe hypoxia (2 mg O2 L-1) on cuttlefish (Sepia officinalis) development (hatching success, development time, mantle length) and behavior, i.e., ability to learn (associative-and socially), to camouflage, and to explore its surroundings spatially. We found that hypoxia yielded lower survival rates, smaller body sizes and inhibited predatory (increased latency to attack the prey) and anti-predator (camouflage) behaviors. Acute and chronic exposure to low oxygen produced similar effects on cognition (inability to socially learn, increased open-field activity levels, no changes in thigmotaxis). It is thus expected that, although cuttlefish can withstand oxygen limitation to a certain degree, expanding hypoxic zones will diminish current habitat suitability.

animal behavior and cognition↗

bioRxiv2023

Transgenerational exposure to deoxygenation and warming disrupts mate-detection in Gammarus locusta

Ocean deoxygenation and warming have been shown to pose a growing threat to the health of marine organisms and ecosystems. Yet, the potential for acclimation and adaptation to these threats remains poorly understood. The aim of this study was to evaluate the effects of transgenerational exposure to reduced oxygen availability and elevated seawater temperature on the chemosensory-dependent mating mechanisms of male amphipods Gammarus locusta. After exposure, the number of individuals that reached adulthood (in F0 and F2) was gauged, and adult males from F0 and F1 were subjected to behavioral trials to assess their capacity of long-distance female cue detection through quantification of (i) response time; (ii) first direction of movement; (iii) activity rate and (iv) proportion of time spent in female scent cues. Ocean warming induced mortality (especially in F2), and reduced oxygen availability had adverse effects on each of the investigated behavioral traits, which were amplified when combined with elevated temperature. Still, when compared to F0, the F1 generation demonstrated more adaptability (i.e., higher activity rate and preference for female odors) to the combination of the two stressors, suggesting positive carry-over effects. Nevertheless, full recovery to control levels was not observed. Altogether, this study indicates that future scenarios of ocean deoxygenation and warming have the potential to disrupt chemosensory-dependent mate-detection in amphipods, but also suggests possible behavioral adaptations. We call for greater research efforts on long-term impacts of ocean change on the behavioral and physiological processes of benthic coastal communities.

ecology↗