Geisinger, A. | bioRxiv Science

bioRxiv2025

Unique and conserved endoplasmic reticulum stress responses in neuroendocrine cells

Endocrine cells are dedicated to the production and processing of hormones, from peptides to small molecules, to regulate key physiological processes, including glucose homeostasis and metabolism. Because of this relatively high productivity, endo-crine cells must handle a variety of stresses from oxidative stress to the unfolded protein response of the endoplasmic reticulum (UPRER). While much is known about the major pathways regulating the UPRER, the roles of endocrine cell type-specific, context-dependent, and time-dependent transcriptional changes are not well explored. To identify unique and shared responses to the UPRER across a subset of endocrine cell types, we tested representative lines for {beta}-cells (insulin), -cells (glucagon), {delta}-cells (somatostatin), X/A-cells (ghrelin), L-cells (glucagon-like peptide 1 (GLP1)), and thyrotropes (thyroid hormone and thyroglobulin). We exposed each cell type to the canonical ER stressor thapsigargin for 6 and 24 h, or vehicle for 24 h and performed mRNA sequencing. Analysis of the data showed all lines responded to thapsigargin. Comparisons of differentially expressed genes between each line revealed both shared and unique transcriptional signatures. These data represent a valuable mineable set of candidate genes that may have cell type-specific functions during the UPRER and have the potential to lead to a new understanding of how different endocrine cells mitigate or succumb to ER stress.

cell biology↗

bioRxiv2020

Familial primary ovarian insufficiency associated with a SYCE1 point mutation: Defective meiosis elucidated in humanized mice

ObjectiveTo investigate if nonsense mutation SYCE1 c.613CT -found in women with familial primary ovarian insufficiency (POI)- is actually responsible for infertility, and to elucidate the involved molecular mechanisms. DesignAs most fundamental mammalian oogenesis events occur during the embryonic phase, thus hindering the study of POIs etiology/pathogeny in infertile women, we have used CRISPR/Cas9 technology to generate a mouse model line with an equivalent genome alteration (humanized mice). SettingAcademic research laboratories. InterventionsWe present the characterization of the biallelic mutant mice phenotype, compared to wild type and monoallelic littermates. AnimalsStudies were conducted employing the generated humanized mice. All studies were performed for both genders, except otherwise stated. Main outcome measuresreproductive capability by fertility tests; gonadal histological analysis; evaluation of chromosome synapsis and synaptonemal complex (SC) assembly by immunolocalizations; protein studies by Western blotting; transcript quantification by RT-qPCR. ResultsThe studied mutation proved to be the actual cause of the infertile phenotype, both in female and male mice homozygous for the change, confirming infertility of genetic origin with a recessive mode of inheritance. The mechanisms that lead to infertility are related to chromosome synapsis defects; no putative truncated SYCE1 protein was observed, and Syce1 transcript was hardly detected in biallelic mutants. ConclusionsWe present for the first time the generation of humanized mice to study the actual consequences of a SC component mutation found in women with familial POI. By this approach we could confirm the suspected etiology, and shed light on the underlying molecular mechanism.

genetics↗