Biology subjects

Neto, A.

Publications and source records attributed to Neto, A..

3 recordsLinked to original sources

bioRxiv2021

Arrival and proliferation of the invasive seaweed Rugulopteryx okamurae in NE Atlantic islands

The present study reports the recent occurrence and expansion of Rugulopteryx okamurae in the Azores archipelago (NE Atlantic). Morphological and molecular characters confirmed the species identification. Quick surveys around the island of Sao Miguel showed that it has successfully colonized the island and is quickly expanding. In some locations, R. okamurae is currently the dominant organism smothering all other benthic biota and posing a serious threat to the benthic ecosystems across the region. The species first record dates from 2019 near the main harbour of the island, suggesting that its introduction was driven by human-assisted transport, via boat ballast waters or adhered to ship hulls and likely originating from the Mediterranean populations that have been proliferating in recent years across the Strait of Gibraltar.

ecology↗

bioRxiv2021

Direct tissue sensing reprograms TLR4+ Tfh-like cells inflammatory profile in the joints of rheumatoid arthritis patients

CD4+ T cells mediate rheumatoid arthritis (RA) pathogenesis through both antibody-dependent and independent mechanisms. It remains unclear how synovial microenvironment impinges on CD4+ T cells pathogenic functions. Here, we identified a TLR4+ follicular helper T (Tfh) cell-like population present in the blood and expanded in synovial fluid. Mechanistically, we unveiled that homotypic T-T cell interactions through non-cognate HLA-DR:TCR contacts regulate TLR4 expression on T cells. TLR4+ T cells possess a two-pronged pathogenic activity. Upon TCR and ICOS engagement, TLR4+ T cells produce IL-21, a cytokine known to sponsor antibody production. However, direct TLR4+ engagement on T cells, by endogenous ligands in the arthritic joint, reprograms them towards an IL-17 inflammatory profile compatible with tissue damage program. Blocking TLR4 signaling with a specific inhibitor impaired IL-17 production in response to synovial fluid recognition. Ex vivo, synovial fluid TLR4+ T cells produced IL-17, but not IL-21. TLR4+ T cells appear to uniquely reconcile an ability to promote systemic antibody production with a local synovial driven tissue damage program. TLR4+ T cells could constitute an attractive cellular target and predictive biomarker for erosive arthritis.

immunology↗

bioRxiv2020

CTCF knockout in zebrafish induces alterations in regulatory landscapes and developmental gene expression

CTCF is an 11-zinc-finger DNA-binding protein that acts as a transcriptional repressor and insulator as well as an architectural protein required for 3D genome folding1-5. CTCF mediates long-range chromatin looping and is enriched at the boundaries of topologically associating domains, which are sub-megabase chromatin structures that are believed to facilitate enhancer-promoter interactions within regulatory landscapes 6-12. Although CTCF is essential for cycling cells and developing embryos13,14, its in vitro removal has only modest effects over gene expression5,15, challenging the concept that CTCF-mediated chromatin interactions and topologically associated domains are a fundamental requirement for gene regulation16-18. Here we link the loss of chromatin structure and gene regulation in an in vivo model and during animal development. We generated a ctcf knockout mutant in zebrafish that allows us to monitor the effect of CTCF loss of function during embryo patterning and organogenesis. CTCF absence leads to loss of chromatin structure in zebrafish embryos and affects the expression of thousands of genes, including many developmental genes. In addition, chromatin accessibility, both at CTCF binding sites and cis-regulatory elements, is severely compromised in ctcf mutants. Probing chromatin interactions from developmental genes at high resolution, we further demonstrate that promoters fail to fully establish long-range contacts with their associated regulatory landscapes, leading to altered gene expression patterns and disruption of developmental programs. Our results demonstrate that CTCF and topologically associating domains are essential to regulate gene expression during embryonic development, providing the structural basis for the establishment of developmental gene regulatory landscapes.

developmental biology↗