Nucleoporin insufficiency disrupts a pluripotent regulatory circuit in a pro-arrhythmogenic stem cell line

Abstract

Nucleoporins have been reported to regulate pluripotent biology, but how they do so remains partially characterized. This study examined the effects of nup155 gene disruption on mouse embryonic stem cells to gain insights into possible mechanisms by which nucleoporins regulate pluripotency in a pro-arrhythmogenic stem cell line. Embryonic stem cells with gene-trapped nup155 exhibited aberrant colony morphology underscored by abnormal transcriptome remodeling. Bioinformatic analysis of whole transcriptome data from nup155 +/− embryonic stem cells revealed changes in a variety of non-coding RNA elements, with significant under expression of miR291a , miR291b , miR293 , and miR294 . These miRNAs are members of the larger regulatory miR290–295 cluster that regulates pluripotency and are controlled by the canonical stem cell-related factors SOX2, OCT4, and NANOG. Expression analysis of these factors revealed downregulation in all three, supported by biochemical profiling and image analysis. These data implicate disruption of the miR -SOX2/OCT4/NANOG regulatory circuit occurs downstream of nup155 gene lesion.

Protein Subdomain Enrichment of NUP155 Variants Identify a Novel Predicted Pathogenic Hotspot

“…In addition, this region mediates NUP155 interaction with the nuclear envelope membrane and plays a critical role in NPC biogenesis (40) that may impair nucleocytoplasmic transport with effects on the functional transcriptome and/or proteome of the cell. Our previous work in which NUP155 deficiency remodels transcriptome profiles in pluripotent cells (11,12) supports this, in addition to earlier studies that identified defective import of HSP70 (10) in nup155 deficient models. Indeed, differential transcriptome/proteome composition could be a significant underlying factor that contributes to impaired cardiogenesis in the presence of preserved NPC assembly and structure, and is an area of future investigation.…”

“…Indeed, earlier studies had identified a NUP155 R391H variant as an inherited underlying cause of atrial fibrillation and sudden pediatric cardiac death in multiple generations of a South American family, while independent work revealed a NUP155 L503F variant associated with sudden cardiac death in a rural Chinese population (9,10). Further evidence for the role of the nuclear envelope in these NUP155 clinical cases is supported by our work as well as others (11)(12)(13), but whether or not other NUP155 variants may be pathogenic remains unknown. As these previously mentioned NUP155 missense mutations as well as dysregulated expression of other discrete nups have been associated with a variety of clinical cardiopathologies (5,10,14), this study was carried out to investigate the prevalence of reported NUP155 variants with potential cardiopathogenicity.…”

Nuclear pore complexes in development and tissue homeostasis

“…A more recent study, has shown that Nup155 +/− ESCs spontaneously form embryoid body-derived cardiomyocytes, with dysregulated electrical function mimicking the previously reported arrhythmogenic phenotype (Preston et al, 2018). Nup155 insufficiency in these cells results in alterations of transcriptome networks involved in cardiac innervation and fibrosis, as well as the deregulation of noncoding RNAs involved in pluripotency maintenance (Preston et al, 2019(Preston et al, , 2018. The transcriptome changes described by these studies highlight a role for Nup155 in regulating gene expression and supports previous studies in which Nup155 has been found to regulate the expression of sarcomeric and Ca 2+ -handling genes through its interaction with histone deacetylase 4 (HDAC4) (Kehat et al, 2011).…”

Epigenetic Regulation of Neural Stem Cells: The Emerging Role of Nucleoporins

“…A recent study revealed that in ESCs, Nup155 disruption induces a decreased expression of pluripotency factors, alteration of a large miRNA cluster involved in pluripotency, and interruption of the miR-SOX2-NANOG-OCT4 regulatory circuit, which impaired stem cell function. 97 Increasing evidence indicates that NPC dependent regulation of gene expression is also achieved by protein SUMOylation level control by Nups. 98 The addition of SUMO polypeptides to targets occurs by sequential SUMO-activation, transfer, and conjugation involving Aos1/Uba2 enzyme (E1), the UBC9 enzyme (E2), and a SUMO ligase (E3), respectively.…”

“…A recent study revealed that in ESCs, Nup155 disruption induces a decreased expression of pluripotency factors, alteration of a large miRNA cluster involved in pluripotency, and interruption of the miR‐SOX2‐NANOG‐OCT4 regulatory circuit, which impaired stem cell function. 97 …”