Biology subjects

del Valle, I.

Publications and source records attributed to del Valle, I..

4 recordsLinked to original sources

bioRxiv2024

The transcriptomic landscape of monosomy X (45,X) during early human fetal and placental development

Monosomy X (45,X) is associated with Turner syndrome and pregnancy loss in humans, but the underlying mechanisms remain unclear. We therefore analyzed the transcriptomic landscape of clinically relevant human fetal 45,X tissues (including pancreas, liver, kidney, skin, placenta) with matched 46,XX and 46,XY control samples between 11-15 weeks post conception (n=78). Although most pseudoautosomal region 1 (PAR1) genes were lower in monosomy X tissues, we also found reduced expression of several key genes escaping X inactivation (e.g., KDM5C and KDM6A), and potentially clinically important transcripts such as genes implicated in ascending aortic aneurysm. In contrast, higher expression of an autosomal, long non-coding RNA (OVCH1-AS1) was seen in all 45,X tissues. In the placenta, lower expression of CSF2RA was demonstrated, likely contributing to immune dysregulation. Taken together, these findings provide novel insights into the biological consequences of a single X chromosome during early human development and potential insights in genetic mechanisms in Turner syndrome.

genetics↗

bioRxiv2024

Sex differences in early human fetal brain development

The influence of sex chromosomes and sex hormones on early human brain development is poorly understood. We therefore undertook transcriptomic analysis of 46,XY and 46,XX human brain cortex samples (n=64) at four different time points between 7.5 and 17 weeks post conception (wpc), in two independent studies. This developmental period encompasses the onset of testicular testosterone secretion in the 46,XY fetus (8wpc). Differences in sex chromosome gene expression included X-inactivation genes (XIST, TSIX) in 46,XX samples; core Y chromosome genes (n=18) in 46,XY samples; and two Y chromosome brain specific genes, PCDH11Y and RP11-424G14.1. PCDH11Y (protocadherin11 Y-linked) regulates excitatory neurons; this gene is unique to humans and is implicated in language development. RP11-424G14.1 is a novel long non-coding RNA. Fewer differences in sex hormone pathway-related genes were seen. The androgen receptor (AR, NR4A2) showed cortex expression in both sexes, which decreased with age. Global cortical sex hormone effects were not seen, but more localized AR mechanisms may be important with time (e.g., hypothalamus). Taken together, our data suggest that limited but potentially important sex differences occur during early human fetal brain development.

developmental biology↗

bioRxiv2022

A cell atlas of human adrenal cortex development and disease

The adrenal glands synthesize and release essential steroid hormones such as cortisol and aldosterone, but the mechanisms underlying human adrenal gland development are not fully understood. Here, we combined single-cell and bulk RNA-sequencing, spatial transcriptomics, immunohistochemistry and micro-focus computed tomography to investigate key aspects of adrenal development in the first 20 weeks of gestation. We demonstrate rapid adrenal growth and vascularization, with cell division in the outer definitive zone (DZ). Steroidogenic pathways favor androgen synthesis in the central fetal zone (FZ), but DZ capacity to synthesize cortisol and aldosterone develops with time. Core transcriptional regulators were identified, with a role for HOPX in the DZ. Potential ligand- receptor interactions between mesenchyme and adrenal cortex were seen (e.g., RSPO3/LGR4). Growth-promoting imprinted genes were enriched in the developing cortex (e.g. IGF2, PEG3). These findings reveal new aspects of human adrenal development, and have clinical implications for understanding primary adrenal insufficiency and related postnatal adrenal disorders, such as adrenal tumor development, steroid disorders and neonatal stress.

developmental biology↗

bioRxiv2020

Tumor to normal single cell mRNA comparisons reveal a pan-neuroblastoma cancer cell

Neuroblastoma is an embryonal childhood cancer that arises from aberrant development of the neural crest, mostly within the fetal adrenal medulla. It is not established what developmental processes neuroblastoma cancer cells represent. Here, we sought to reveal the phenotype of neuroblastoma cancer cells by comparing cancer (n=16,591) with fetal adrenal single cell transcriptomes (n=57,972). Our principal finding was that the neuroblastoma cancer cell resembled fetal sympathoblasts, but no other fetal adrenal cell type. The sympathoblastic state was a universal feature of neuroblastoma cells, transcending cell cluster diversity, individual patients and clinical phenotypes. We substantiated our findings in 652 neuroblastoma bulk transcriptomes and by integrating canonical features of the neuroblastoma genome with transcriptional signals. Overall, our observations indicate that there exists a pan-neuroblastoma cancer cell state which may be an attractive target for novel therapeutic avenues.

cancer biology↗