Biology subjects

Rodriguez-Polo, I.

Publications and source records attributed to Rodriguez-Polo, I..

3 recordsLinked to original sources

bioRxiv2025

Non-canonical enhancers control gene expression and cell fate in human pluripotent stem cells

Enhancers are key gene regulatory elements that ensure the precise spatiotemporal execution of developmental gene expression programmes. However recent findings indicate that approaches to identify enhancers may not capture the full repertoire of active enhancers in mammalian genomes. Here, we combine massively parallel enhancer assays with chromatin structure and transcriptome profiling to functionally annotate enhancers genome-wide in human induced pluripotent stem cells. We find that a substantial fraction ([~]40%) of accessible chromatin regions with enhancer function lack key features associated with active enhancers, including the active enhancer mark histone H3 lysine 27 acetylation and enhancer-associated RNAs. Perturbation of this class of non-canonical enhancers by CRISPR-mediated epigenome editing results in decreased levels of target gene expression and, in one instance, loss of pluripotent stem cell characteristics. Collectively, our data demonstrate enhancer activity for a class of gene regulatory elements that had until now only been associated with a neutral or inactive status, challenging current models of enhancer function.

genomics↗

bioRxiv2024

Modelling co-development between somites and neural tube with human Trunk-like Structures (hTLS)

Human stem cell-based embryo models have opened new avenues of research in development by providing experimentally amenable in vitro systems. One of the features of embryo models is their multilineage differentiation, which allows the co-development of, and interactions between, tissues. Here, we utilise a human Trunk-like Structure (hTLS) model to explore trunk development. We show that hTLS have morphologically organised somites and a neural tube that form through self-organised, endogenous signalling including anteroposterior FGF, Wnt and Retinoic Acid (RA) gradients that modulate the fate of neuromesodermal progenitors. Comparison to an existing dataset from organogenesis-stage human embryos shows that hTLS cells approximate Carnegie Stage 13-14 (28-35 days post-fertilisation). The absence of a notochord leads to a dorsal identity, but exogenous exposure to smoothened agonist (promoting Sonic Hedgehog signalling) progressively ventralises both somites and neural tube in a dose-dependent manner. Furthermore, we identify endogenous signalling from the neural tube to the somites, which leads to medially localised ALDH1A2, and subsequent RA signalling from the somites to the neural tube, which leads to spontaneous neural progenitor patterning and PAX6 expression. Together, our data highlight the value of modularity in embryo models which we leverage to explore human trunk co-development. SummaryUsing a 3D, stem cell-based model of human embryonic trunk development, we examine the interactions across somitic and neural tissues to better understand the dynamics of human trunk co-development.

developmental biology↗

bioRxiv2020

Controlling the switch from neurogenesis to pluripotency during marmoset monkey somatic cell reprogramming with self-replicating mRNAs and small molecules

Induced pluripotent stem cells (iPSCs) hold enormous potential for the development of cell-based therapies for many currently incurable diseases. However, the safety and efficacy of potential iPSC-based treatments need to be verified in relevant animal disease models before their application in the clinic. Moreover, in order to reduce possible risks for the patients, it is necessary to use reprogramming approaches that ensure to the greatest extent possible the genomic integrity of the cells. Here, we report the derivation of iPSCs from common marmoset monkeys (Callithrix jacchus) using self-replicating mRNA vectors based on the Venezuelan equine encephalitis virus (VEE-mRNAs). By transfection of marmoset fetal fibroblasts with Tomato-modified VEE-mRNAs carrying the human OCT4, KLF4, SOX2, and c-MYC (VEE-OKS-iM-iTomato) and culture in medium supplemented with two small molecule inhibitors, we first established intermediate primary colonies with neural progenitor-like properties. In the second reprogramming step, we converted these colonies into transgene-free pluripotent stem cells by further culturing them with customized marmoset iPSC medium in feeder-free conditions. The resulting cell lines possess pluripotency characteristics, such as expression of various pluripotency markers, long-term self-renewal, stable karyotype, and ability to differentiate into derivatives of the three primary germ layers in vitro and in vivo. Our experiments reveal a novel paradigm for flexible reprogramming of somatic cells, where primary colonies obtained by a single VEE-mRNA transfection can be directed either towards the neural lineage or further reprogrammed to pluripotency. These results (i) will further enhance the role of the common marmoset as animal disease model for preclinical testing of iPSC-based therapies and (ii) establish an in vitro system to experimentally address developmental signal transduction pathways in primates.

bioengineering↗