Biology subjects

Tavares, L.

Publications and source records attributed to Tavares, L..

4 recordsLinked to original sources

bioRxiv2026

GM-CSF regulates ILC states and myeloid cell signaling during ulceration in Crohns disease

Macrophage (M-), granulocyte (G-), and granulocyte-macrophage (GM-) colony-stimulating factors (CSFs) regulate myeloid cell function, yet their relative roles during inflammation remain poorly defined. To uncover how CSFs shape spatial immune niches in Crohns disease, we performed Xenium single-cell spatial transcriptomics on ileal tissues, revealing cell-type-specific expression and source-target interactions for each CSF. GM-CSF, unlike M-CSF or G-CSF, was locally enriched in ulcerated regions where lymphocytes adjacent to macrophage aggregates signaled through STAT5 phosphorylation. To study functional consequences, we developed a csf2rb-/- zebrafish model of intestinal injury. Using this model, we found that loss of GM-CSF signaling exacerbated epithelial damage and inflammation, whereas recombinant human GM-CSF limited injury by restraining ILC1 expansion, sustaining ILC3 maintenance, and promoting IL-22 production. Cross-species single-cell analysis revealed conserved ILC gene modules and GM-CSF-dependent transcriptional networks linking lymphoid and myeloid populations. These findings establish GM-CSF as a critical spatial regulator of myeloid- lymphoid crosstalk and intestinal immune homeostasis in Crohns disease.

immunology↗

bioRxiv2021

Positional and Compositional Analysis of Saturated, Monounsaturated and Polyunsaturated Fatty acids in Human Adipose Tissue Triglyceride by 13C NMR

Objectives and new findings, ends with short conclusion, no referencesThe synthesis and turnover of triglyceride in adipose tissue involves enzymes with preferences for specific fatty acid classes and/or regioselectivity with regard to the fatty acid position within the glycerol moiety. The focus of the present study was to characterize both the fatty acid composition and their positional distribution in triglycerides of biopsied human subcutaneous adipose tissue using 13C NMR spectroscopy. The triglyceride sn2 position was significantly more enriched with monounsaturated fatty acids compared to the sn1,3 sites, while saturated fatty acids abundance was significantly lower in the sn2 position compared to that of sn1,3. Furthermore, the analysis revealed significant positive correlations between the total fraction of palmitoleic acid with both BMI and HOMA-IR scores. Additionally, we established that 13C NMR chemical shifts for {omega} -3 signals, centered at 31.9 ppm, provided superior resolution of the most abundant FA species, including palmitoleate, compared to the {omega} -2 signals that were used previously. 13C NMR spectroscopy reveals for the first time a highly non-homogenous distribution of FA in the glycerol sites of human adipose tissue triglyceride and that these distributions are correlated with different phenotypes such as BMI and insulin resistance.

biochemistry↗

bioRxiv2020

Taxonomic classification of strain PO100/5 shows a broader geographic distribution and genetic markers of the recently described Corynebacterium silvaticum

The bacterial strain PO100/5 was isolated from a skin abscess of a pig (Sus scrofa domesticus) in the Alentejo region of southern Portugal. It was identified as Corynebacterium pseudotuberculosis using biochemical tests, multiplex PCR and Pulsed Field Gel Electrophoresis. After genome sequencing and rpoB phylogeny, the strain was classified as C. ulcerans. To better understand the taxonomy of this strain and improve identification methods, we compared strain PO100/5 to other publicly available genomes from the C. diphtheriae group. Taxonomic analysis reclassified it and three others strains as belonging to the recently described C. silvaticum, which have been isolated from wild boar and roe deer in Germany and Austria. The results showed that PO100/5 is the first sequenced genome of a C. silvaticum strain from a domestic animal and a different geographical region, is a putative producer of the diphtheriae toxin, and has a unique sequence type. Genomic analysis of PO100/5 showed four prophages and eight conserved genomic islands when compared to C. ulcerans. Pangenome analysis of 38 C. silvaticum and 76 C. ulcerans samples suggest that C. silvaticum is a clonal species, with 73.6% of conserved genes and a pangenome near to being closed ( > 0.952). 172 conserved genes are unique to C. silvaticum when compared to C. ulcerans, with most related to nutrient uptake and metabolism, prophages or immune evasion. These unique genes could be used as genetic markers for species identification. This information can be useful for identification and surveillance of this pathogen, especially in regard to the possibility of zoonotic transmission.

genomics↗

bioRxiv2020

The Pebble/Rho1/Anillin pathway controls polyploidization and axonal wrapping activity in the glial cells of the Drosophila eye

During development glial cell are crucially important for the establishment of neuronal networks. Proliferation and migration of glial cells can be modulated by neurons, and in turn glial cells can differentiate to assume key roles such as axonal wrapping and targeting. To explore the roles of actin cytoskeletal rearrangements in glial cells, we studied the function of Rho1 in Drosophila developing visual system. We show that the Pebble (RhoGEF)/Rho1/Anillin pathway is required for glia proliferation and to prevent the formation of large polyploid perineurial glial cells, which can still migrate into the eye disc if generated. Surprisingly, this Rho1 pathway is not necessary to establish the total glial membrane area or for the differentiation of the polyploid perineurial cells. The resulting polyploid wrapping glial cells are able to initiate wrapping of axons in the basal eye disc, however the arrangement and density of glia nuclei and membrane processes in the optic stalk are altered and the ensheathing of the photoreceptor axonal fascicles is reduced.

developmental biology↗