Biology subjects

Boutin, M.

Publications and source records attributed to Boutin, M..

4 recordsLinked to original sources

bioRxiv2022

Influence of sex-limited mimicry on extinction risk in Aculeata: a theoretical approach.

AO_SCPLOWBSTRACTC_SCPLOWPositive ecological interactions can play a role in community structure and species co-existence. A well-documented case of mutualistic interaction is Mullerian mimicry, the convergence of colour pattern in defended species living in sympatry. By reducing predation pressure, Mullerian mimicry may limit local extinction risks of defended species, but this positive effect can be weakened by undefended mimics (Batesian mimicry). While mimicry was well-studied in neotropical butterflies, it remains surprisingly poorly studied in wasps and bees (Hymenoptera: Aculeata). However, only females are defended in Aculeata and this female-limited defence may modulate the effect of Mullerian mimicry on extinction risks. Here, we focus on the effect of Mullerian mimicry on extinction risk in Aculeata, using a population dynamics model for two species. We show that Mullerian mimicry has a positive effect on species co-existence, but this effect depends on the sex-ratio. We found that the probability of extinction increases as the proportion of undefended males increases in the population, however co-existence still occurs if females are sufficiently abundant or noxious. Furthermore, we detected a destabilising effect of dual sex-limited mimicry (when each sex resembles a different model) on species co-existence. In a context of massive population decline caused by anthropic activities, our findings highlight the potential importance of Mullerian mimicry as an overlooked mechanism linked to extinction risk in wasp and bee species.

ecology↗

bioRxiv2022

A third SARS-CoV-2 mRNA vaccine dose in people receiving hemodialysis overcomes B cell defects but elicits a skewed CD4+ T cell profile

Cellular immune defects associated with suboptimal responses to SARS-CoV-2 mRNA vaccination in people receiving hemodialysis (HD) are poorly understood. We longitudinally analyzed antibody, B cell, CD4+ and CD8+ T cell vaccine responses in 27 HD patients and 26 low-risk control individuals (CI). The first two doses elicit weaker B cell and CD8+ T cell responses in HD than in CI, while CD4+ T cell responses are quantitatively similar. In HD, a third dose robustly boosts B cell responses, leads to convergent CD8+ T cell responses and enhances comparatively more Thelper (TH) immunity. Unsupervised clustering of single-cell features reveals phenotypic and functional shifts over time and between cohorts. The third dose attenuates some features of TH cells in HD (TNF/IL-2 skewing), while others (CCR6, CXCR6, PD-1 and HLA-DR overexpression) persist. Therefore, a third vaccine dose is critical to achieve robust multifaceted immunity in hemodialysis patients, although some distinct TH characteristics endure.

immunology↗

bioRxiv2022

Functional brain region-specific neural spheroids for modeling neurological diseases and therapeutics screening

3D spheroids have emerged as powerful drug discovery tools given their high-throughput screening (HTS) compatibility. Here, we established a method for generating functional neural spheroids with differentiated human induced pluripotent stem cell (hiPSC)-derived neurons and astrocytes at cell type compositions mimicking specific regions of the human brain. Recordings of intracellular calcium oscillations were used as functional assays, and the utility of this spheroids system was shown through disease modelling, drug testing, and formation of assembloids to model neurocircuitry. We developed disease models for Alzheimers and Parkinsons Disease through incorporating genetically engineered cells into spheroids, and Opioid Use Disorder by chronically treating spheroids with DAMGO. We reversed baseline functional deficits in each disease model with clinically approved treatments and showed that assembloid activity can be chemogenetically manipulated. Here, we lay the groundwork for brain region-specific spheroids as a robust functional assay platform for HTS studies.

bioengineering↗

bioRxiv2021

SARS-CoV-2 Omicron Spike recognition by plasma from individuals receiving BNT162b2 mRNA vaccination with a 16-weeks interval between doses

Continuous emergence of SARS-CoV-2 variants of concern (VOC) is fueling the COVID-19 pandemic. Omicron (B.1.1.529), is rapidly spreading worldwide. The large number of mutations in its Spike raised concerns about a major antigenic drift that could significantly decrease vaccine efficacy and infection-induced immunity. A long interval between BNT162b2 mRNA doses was shown to elicit antibodies that efficiently recognize Spikes from different VOCs. Here we evaluated the recognition of Omicron Spike by plasma from a cohort of SARS-CoV-2 naive and previously-infected individuals that received their BNT162b2 mRNA vaccine 16-weeks apart. Omicron Spike was recognized less efficiently than D614G, Alpha, Beta, Gamma and Delta Spikes. We compared to plasma activity from participants receiving a short (4-weeks) interval regimen. Plasma from individuals of the long interval cohort recognized and neutralized better the Omicron Spike compared to those that received a short interval. Whether this difference confers any clinical benefit against Omicron remains unknown.

microbiology↗