Biology subjects

da Silva, J. A.

Publications and source records attributed to da Silva, J. A..

3 recordsLinked to original sources

bioRxiv2026

Optimization of breeding conditions in Danionella cerebrum to advance its use as a vertebrate model

We systematically evaluated tank configuration and spawning-tube parameters to improve egg production and collection efficiency in Danionella cerebrum. A shallow breeding tank with a black bottom significantly increased egg production while facilitating egg collection. Further optimization of spawning-tube parameters revealed a strong effect of tube diameter on reproductive performance, with narrower tubes improving fertilization efficiency and a 4-mm inner diameter yielding the highest egg production. Longer tubes also tended to increase egg production, although the difference between 5- and 10-cm tubes was not significant. While 5-cm tubes facilitated routine egg collection, the trend toward higher egg production and greater water volume of 10-cm tubes enabled short-term in-tube embryo culture, providing an alternative workflow when frequent egg collection is unnecessary. Notably, increasing the number of available spawning tubes did not further enhance egg production; instead, analysis of tube usage revealed a preference for previously used spawning sites. Together, these findings establish practical breeding parameters that improve reproductive output and streamline egg collection and embryo handling in D. cerebrum.

developmental biology↗

bioRxiv2025

Integrin β1-Talin1 at focal adhesions underpin uncontrolled endothelial cell enlargement in live cerebral cavernous malformation vasculature

Cerebral cavernous malformations (CCMs) are vascular anomalies caused by loss of CCM gene function and consequent hyperactivation of MEKK3-KLF2/4 signaling in endothelial cells. Excess integrin {beta}1 activity has been associated with lesion growth, yet the precise mechanistic and biomechanical roles of the integrin-KLF2/4 hierarchy in CCM cellular pathogenesis are not fully understood. Using live imaging of endothelial Vinculin in Ccm1-deficient zebrafish, we demonstrate excessive, mechanically active focal adhesions in an in vivo model of CCM pathology. We validate this in CCM1-deficient endothelial cells and show a redistribution of mechanical tension from cell-cell junctions to focal adhesions. Genetic deletion of Talin1 to decouple focal adhesions from the cell cortex and inhibit integrin {beta}1 signaling demonstrates the integrin {beta}1-Talin1 complex is essential for vascular malformations in ccm1 mutants by driving endothelial cell enlargement. We show integrin {beta}1-Talin1 act independent or downstream of KLF2/4, rather than upstream as previously suggested. Thus, we reposition the role of integrin {beta}1-Talin1 in CCM pathogenesis, demonstrating an essential function in driving cell enlargement, which underpins lesion growth.

cell biology↗

bioRxiv2022

Dynamically regulated Focal adhesions coordinate endothelial cell remodelling in developing vasculature

The assembly of a mature vascular network involves the coordinated control of cell shape changes to regulate morphogenesis of a complex vascular network. Cellular changes include a process of endothelial cell (EC) elongation which is essential for establishing appropriately sized lumens during vessel maturation1-3. However how EC elongation is dynamically regulated in vivo is not fully understood since live monitoring of this event can be challenging in animal models. Here, we utilise the live imaging capacity of the zebrafish to explore how integrin adhesion complexes, known as Focal Adhesions (FAs), control EC dynamics in live flow pressured vasculature. To do this, we generated a zebrafish mutant, deficient for the integrin adaptor protein Talin1. Notably, unlike the severe cardiovascular defects that arise in Talin1 knockout mice4, vasculogenesis still occurs normally talin1 mutants and cardiac output remains sufficient up to two days post fertilisation (dpf). This allowed us to uncouple primary roles for FAs in ECs during subsequent morphogenesis events, including angiogenesis and vessel remodelling, without interference of secondary effects that might occur due to systemic vessel failure or loss of blood flow. We further established a FA marker line, expressing endothelial Vinculin-eGFP, and demonstrated that FAs are lost in our talin1 mutants. This Vinculin transgene represents the first in vivo model to monitor endothelial FA dynamics. Loss of FAs in talin1 mutants, leads to compromised F-actin rearrangements, which perturb EC elongation and cell-cell junction linearisation during vessel remodelling. Chemical induction of actin polymerisation can restore these cellular phenotypes, suggesting a recovery of actin rearrangements that are sufficient to allow cell and junction shape changes. Together, we have identified that FAs are essential for active guidance of EC elongation and junction linearisation in flow pressured vessels. These observations can explain the severely compromised vessel beds, haemorrhage and vascular leakage that has been observed in mouse models that lack integrin signalling4-8.

cell biology↗