Biology subjects

Simoes, F. C.

Publications and source records attributed to Simoes, F. C..

4 recordsLinked to original sources

bioRxiv2026

Cardiac-immune microniches programme macrophage states in the regenerating heart

Adult zebrafish regenerate their hearts after injury, a process that requires macrophages, yet how local tissue microenvironments instruct macrophage states and function remains unclear. Here we combine single cell RNA sequencing with Visium and high-resolution MERFISH spatial transcriptomics to map the cardio-immune landscape of homeostatic and regenerating zebrafish hearts. We identify a mpeg1.1+ compartment comprising macrophages, dendritic, B and NK-like cells, and show that injury establishes a macrophage-centred immune environment with transcriptional programmes spanning resident surveillance, damage sensing, inflammation, antigen presentation, resolution and metabolic support. Communication-aware spatial modelling reveals that these states are not randomly distributed but organised into discrete structural-immune microniches across the injury region, each defined by stereotyped cellular compositions and ligand-receptor circuits. Within a fibroblast-macrophage microniche, we uncover an il34-csf1ra-egr1 axis in which col12a1a+ il34+ fibroblasts promote an egr1 pro-regenerative macrophage state that couples fibrosis, vascular integrity and epicardial signalling. We show that disruption of this axis by csf1ra loss of function reduces macrophage-, endothelial- and epicardial-rich microniches, amplifying fibroblast-driven domains that shift macrophages towards stress and long-sustained inflammatory programmes, thereby biasing early injury response towards a pro-fibrotic state. Our work establishes spatially defined cardio-immune microniches as key organisers of macrophage function and regenerative outcome, providing a mechanistic framework and actionable targets for reprogramming cardiac repair.

developmental biology↗

bioRxiv2021

Distinct epicardial gene regulatory programmes drive development and regeneration of the zebrafish heart

Unlike the adult mammalian heart, which has limited regenerative capacity, the zebrafish heart can fully regenerate following injury. Reactivation of cardiac developmental programmes is considered key to successfully regenerating the heart, yet the regulatory elements underlying the response triggered upon injury and during development remain elusive. Organ-wide activation of the epicardium is essential for zebrafish heart regeneration and is considered a potential regenerative source to target in the mammalian heart. Here we compared the transcriptome and epigenome of the developing and regenerating zebrafish epicardium by integrating gene expression profiles with open chromatin ATAC-seq data. By generating gene regulatory networks associated with epicardial development and regeneration, we inferred genetic programmes driving each of these processes, which were largely distinct. We identified wt1a, wt1b, and the AP-1 subunits junbb, fosab and fosb as central regulators of the developing network, whereas hif1ab, zbtb7a, tbx2b and nrf1 featured as putative central regulators of the regenerating epicardial network. By interrogating developmental gene regulatory networks that drive cell-specific transcriptional heterogeneity, we tested novel subpopulation-related epicardial enhancers in vivo. Taken together, our work revealed striking differences between the regulatory blueprint deployed during epicardial development and regeneration. These findings challenge the dogma that heart regeneration is essentially a reactivation of developmental programmes, and provide important insights into epicardial regulation that can assist in developing therapeutic approaches to enable tissue regeneration in the adult mammalian heart.

developmental biology↗

bioRxiv2018

Functional heterogeneity within the developing zebrafish epicardium

The epicardium is essential during cardiac development, homeostasis and repair and yet fundamental insights into its underlying cell biology, notably epicardium formation, lineage heterogeneity and functional cross-talk with other cell types in the heart, are currently lacking. In this study, we investigated epicardial heterogeneity and the functional diversity of discrete epicardial subpopulations in the developing zebrafish heart. Single-cell RNA-sequencing uncovered three epicardial subpopulations with specific genetic programmes and distinctive spatial distribution within the developing heart. Perturbation of unique gene signatures uncovered distinct functions associated with each subpopulation and established novel epicardial roles in cell adhesion, migration, and chemotaxis as a mechanism for recruitment of leukocytes into the heart. This work elucidates the mutual spatiotemporal relationships between different epicardial subpopulations and assigns unique function to each during cardiac development. Understanding which mechanisms cells employ to establish a functional epicardium and to communicate with other cardiovascular cell types during development will bring us closer to repairing cellular relationships that are disrupted during cardiovascular disease.

developmental biology↗

bioRxiv2018

Re-purposing Ac/Ds transgenic system for CRISPR/dCas9 modulation of enhancers and non-coding RNAs in zebrafish

Due to its genetic amenability coupled with recent advances in genome editing, the zebrafish serves as an excellent model to examine the function of both coding and non-coding elements. Recently, the non-coding genome has gained prominence due to its critical role in development and disease. Here, we have re-purposed the Ac/Ds maize transposition system to reliably screen and efficiently characterise zebrafish enhancers, with or without germline propagation. We further utilised the system to stably express guide RNAs in microinjected embryos enabling tissue-specific CRISPR/dCas9-interference (CRISPRi) knockdown of lncRNA and enhancer activity without disrupting the underlying genetic sequence. Our study highlights the utility of Ac/Ds transposition for transient epigenome modulation of non-coding elements in zebrafish.\n\nSummary statementWe adapted the Ac/Ds transposition system, which enables continuous expression of guide RNAs for CRISPR/dCas9 perturbation, to examine the function of non-coding RNAs and enhancer elements in zebrafish.

developmental biology↗