Biology subjects

Rubiolo, J. A.

Publications and source records attributed to Rubiolo, J. A..

3 recordsLinked to original sources

bioRxiv2025

miR-133a and miR-338-3p Shape Neural Crest Derivatives in Zebrafish

Neural crest (NC) cells are a transient, multipotent cell population that contributes to the formation of diverse tissues during vertebrate development. While numerous transcription factors and signalling pathways regulate NC specification and differentiation, the role of microRNAs (miRNAs) in these processes remains underexplored. In this study, we employed a double-transgenic zebrafish model (Tg(sox10:eGFP, sox10:mRFP)), in combination with fluorescence-activated cell sorting (FACS) and RNA sequencing, to identify miRNAs enriched in NC cells and assess their role in the development of NC derivatives. Given the parallels between NC development and tumorigenesis, we focused on a subset of miRNAs previously implicated in cancer progression. Functional assays revealed that overexpression of miR-133a and miR-338-3p resulted in significant craniofacial cartilage malformations and a reduction in melanophore numbers, correlating with the downregulation of key developmental genes, such as sox9b, sox10, and runx3. Reporter assays further demonstrated that miR-133a and miR-338-3p directly target the 3 untranslated region (3UTR) of sox9b, supporting their role in translational repression and mRNA degradation. Additionally, miR-338-3p overexpression increased the overall NC cell population, suggesting a regulatory function in cell proliferation. These findings offer new insights into the molecular mechanisms governing NC development and highlight functional parallels between miRNA-mediated NC regulation and tumour biology. Given that miR-133a and miR-338-3p are known tumour suppressors, their roles in NC differentiation and proliferation may reflect conserved pathways underlying both embryogenesis and oncogenesis. This study enhances our understanding of miRNA function in vertebrate embryogenesis and underscores their potential relevance in neurocristopathies and NC-derived cancers.

developmental biology↗

bioRxiv2022

A chromosome-level genome assembly enables the identification of the follicle stimulating hormone receptor as the master sex determining gene in Solea senegalensis

Sex determination (SD) mechanisms are exceptionally diverse and show high evolutionary rates in fish. Pleuronectiformes is an emblematic fish group characterized by its adaptation to demersal life and its compact genomes. Here, we present a chromosome-level genome assembly of Senegalese sole, a promising European aquaculture species. We combined long- and short-read sequencing and a highly dense genetic map to obtain a contiguous assembly of 613 Mb (N50 = 29.0 Mb, 99% of the assembly in the n = 21 chromosomes of its karyotype). The correspondence between this new assembly and the Senegalese sole chromosomes was established by fluorescence in situ hybridization with BAC probes. Orthology within Pleuronectiformes was assessed by using the chromosome-level genomes of six important commercial flatfishes covering a broad phylogenetic spectrum of the order. A total of 7936 single-gene orthologues, shared by the six species, were used to identify syntenies in Pleuronectiformes and to explore chromosome evolutionary patterns in the order. Whole genome resequencing of six males and six females enabled the identification of 41 fixed allelic variants in the follicle stimulating hormone receptor (fshr) gene, homozygous in females and heterozygous in males, consistent with an XX / XY chromosome system. The observed association between fshr SNPs and sex was confirmed at the species level in a broad sample, which allowed tuning up a molecular sexing tool. Fshr demonstrated differential gene expression between male and female gonads since 86 days post-fertilization, when the gonad was still an undifferentiated primordium, concomitant with the activation of other testis and ovary marker genes, such as amh and cyp19a1a genes, respectively. Interestingly, the Y-linked fshr allele, which included 24 non-synonymous variants, expressed to a higher level than the X-linked allele at all stages. We hypothesize a molecular mechanism hampering the action of the follicle stimulating hormone that would drive the undifferentiated gonad toward testis.

genomics↗

bioRxiv2021

Inhibition of mitochondrial dynamics preferentially targets pancreatic cancer cells with enhanced tumorigenic and invasive potential

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest tumors, partly due to its intrinsic aggressiveness, metastatic potential, and chemoresistance of the contained cancer stem cells (CSCs). Pancreatic CSCs strongly rely on mitochondrial metabolism to maintain their stemness, therefore representing a putative target for their elimination. Since mitochondrial homeostasis depends on the tightly controlled balance between fusion and fission processes, namely mitochondrial dynamics, we aimed to study this mechanism in the context of stemness. In human PDAC tissues, the mitochondrial fission gene DNM1L (DRP1) was overexpressed and positively correlated with the stemness signature. Moreover, we observed that primary human CSCs display smaller mitochondria and a higher DRP1/MFN2 expression ratio, indicating activation of mitochondrial fission. Interestingly, treatment with the DRP1 inhibitor mDivi-1 induced dose-dependent apoptosis, especially in CD133+ CSCs, due to accumulation of dysfunctional mitochondria and subsequent energy crisis in this subpopulation. Mechanistically, mDivi-1 inhibited stemness-related features, such as self-renewal, tumorigenicity and invasiveness, and chemosensitized the cells to the cytotoxic effects of Gemcitabine. In summary, mitochondrial fission is an essential process for pancreatic CSCs and represents an attractive target for designing novel multimodal treatments that will more efficiently eliminate cells with high tumorigenic potential. Simple SummaryDue to their intrinsic aggressiveness, cancer stem cells (CSCs) represent an essential target for the design of effective treatments against pancreatic cancer, one of the deadliest tumors. As pancreatic CSCs are particularly dependent on the activity of their mitochondria, we here focus on mitochondrial dynamics as a critical process in the homeostasis of these organelles. We found that pancreatic CSCs rely on mitochondrial fission, and its pharmacological inhibition by mDivi-1 resulted in the accumulation of dysfunctional mitochondria, provoking energy crisis and cell death in this subpopulation. Consequently, mDivi-1 blocked cellular functions related to cancer aggressiveness such as in vivo tumorigenicity, invasiveness and chemoresistance. Our data suggest that inhibition of mitochondrial fission represents a promising target for designing new multimodal therapies to fight pancreatic cancer.

cancer biology↗