From immature to mature epithelium: unveiling structural dynamics and transcriptional programs in rainbow trout intestinal barrier
Abstract
The intestinal epithelium is crucial for nutrient absorption, immune defense, and barrier function in farmed fish. However, the molecular mechanisms underlying its development and maturation in salmonids remain poorly characterized, hindering our ability to address pervasive gut health challenges in aquaculture. In this study, we use the RTgutGC cell line to implement an epithelial maturation model with the aim of characterizing the global transcriptional program in rainbow trout (Oncorhynchus mykiss). We evaluated in vitro culture conditions to generate a polarized epithelial barrier with high transepithelial electrical resistance (TEER = 75.8 Ω × cm2), low permeability (6.2 × 10–6 cm/s), and well-defined apical specializations, including microvilli-like structures and clusters of these structures (brush border). Comparative transcriptomic profiling between immature (7 days post-seeding, dps) and mature (28 dps) epithelia revealed 3,817 differentially expressed genes (DEGs). Functional enrichment analysis showed that maturation was characterized by the downregulation of proliferative and ribosomal pathways and the concerted upregulation of processes critical for barrier function, including transmembrane transport, proteolysis, cell adhesion, extracellular matrix organization, and tight junction assembly. We identified a core set of 60 genes indicators of epithelial maturation, encompassing solute transporters (slc26a6, slc43a2), tight junction proteins (tjp1, cldn1, cldn3, cldn5, cldn18, among others), and structural components essential for microvilli formation and polarization (cdhr5b, pard6a). By integrating ultrastructural, functional, and transcriptomic data, this study established a framework for future mechanistic investigations into gut development and maturation in vitro. This set of mature epithelium indicators has diverse applications, such as the design of nutritional and pharmacological interventions to improve gut health and resilience in farmed fish.
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BibTeX
@article{talamillaespinoza2026from,
title = {{From immature to mature epithelium: unveiling structural dynamics and transcriptional programs in rainbow trout intestinal barrier}},
author = {Andrea Talamilla-Espinoza and Francisca Vera-Tamargo and Mario Caruffo and Miltha Hidalgo and Daniela Ortiz and Leonardo Rodríguez and Dinka Mandakovic and Ana Riveros and Omar Porras and Rodrigo Pulgar},
journal = {Veterinary Research},
year = {2026},
month = sep,
doi = {10.1186/s13567-026-01766-2},
url = {https://hal.science/hal-05756336v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - From immature to mature epithelium: unveiling structural dynamics and transcriptional programs in rainbow trout intestinal barrier
AU - Andrea Talamilla-Espinoza
AU - Francisca Vera-Tamargo
AU - Mario Caruffo
AU - Miltha Hidalgo
AU - Daniela Ortiz
AU - Leonardo Rodríguez
AU - Dinka Mandakovic
AU - Ana Riveros
AU - Omar Porras
AU - Rodrigo Pulgar
PY - 2026
DA - 2026/09/21
JO - Veterinary Research
DO - 10.1186/s13567-026-01766-2
UR - https://hal.science/hal-05756336v1
AB - The intestinal epithelium is crucial for nutrient absorption, immune defense, and barrier function in farmed fish. However, the molecular mechanisms underlying its development and maturation in salmonids remain poorly characterized, hindering our ability to address pervasive gut health challenges in aquaculture. In this study, we use the RTgutGC cell line to implement an epithelial maturation model with the aim of characterizing the global transcriptional program in rainbow trout (Oncorhynchus mykiss). We evaluated in vitro culture conditions to generate a polarized epithelial barrier with high transepithelial electrical resistance (TEER = 75.8 Ω × cm2), low permeability (6.2 × 10–6 cm/s), and well-defined apical specializations, including microvilli-like structures and clusters of these structures (brush border). Comparative transcriptomic profiling between immature (7 days post-seeding, dps) and mature (28 dps) epithelia revealed 3,817 differentially expressed genes (DEGs). Functional enrichment analysis showed that maturation was characterized by the downregulation of proliferative and ribosomal pathways and the concerted upregulation of processes critical for barrier function, including transmembrane transport, proteolysis, cell adhesion, extracellular matrix organization, and tight junction assembly. We identified a core set of 60 genes indicators of epithelial maturation, encompassing solute transporters (slc26a6, slc43a2), tight junction proteins (tjp1, cldn1, cldn3, cldn5, cldn18, among others), and structural components essential for microvilli formation and polarization (cdhr5b, pard6a). By integrating ultrastructural, functional, and transcriptomic data, this study established a framework for future mechanistic investigations into gut development and maturation in vitro. This set of mature epithelium indicators has diverse applications, such as the design of nutritional and pharmacological interventions to improve gut health and resilience in farmed fish.
SN - 0928-4249
SN - 1297-9716
ER -