Inhibition of E-cad in mouse embryonic stem cells (mESCs) leads to a switch from LIF-BMP to Activin/Nodal-dependent pluripotency, consistent with transition from a naïve to primed pluripotent phenotype. We have used both genetic ablation and steric inhibition of E-cad function in mESCs to assess alterations to phenotype using quantitative mass spectrometry analysis, network models, and functional assays. Proteomic analyses revealed that one third of detected proteins were altered in E-cad null mESCs (Ecad−/− mESCs) compared to wild type (624 proteins were downregulated and 705 were proteins upregulated). Network pathway analysis and subsequent cellular flux assays confirmed a metabolic shift from oxidative phosphorylation (OXPHOS) to aerobic glycolysis, specifically through mitochondrial complex III downregulation and hypoxia inducible factor 1a target upregulation. Central to this was the transcriptional coactivator EP300. E-cad is a well-known tumor suppressor, its downregulation during cancer initiation and metastasis can be linked to the metabolic switch known as Warburg effect. This study highlights a phenomena found in both primed pluripotent state and cancer stemness and links it to loss of E-cad. Data are available via ProteomeXchange with identifier PXD012679.
5 October 2021 in Molecular Therapy - Methods & Clinical Development
The application of induced pluripotent stem cells (iPSCs) in advanced therapies is increasing at pace, but concerns remain over their clinical safety profile. We report the first-ever application of doggybone DNA (dbDNA) vectors to generate human iPSCs. dbDNA vectors are closed-capped linear double-stranded DNA gene expression cassettes that contain no bacterial DNA and are amplified by a chemically defined, current good manufacturing practice (cGMP)-compliant methodology. We achieved comparable iPSC reprogramming efficiencies using transiently expressing dbDNA vectors with the same iPSC reprogramming coding sequences as the state-of-the-art OriP/EBNA1 episomal vectors but, crucially, in the absence of p53 shRNA repression. Moreover, persistent expression of EBNA1 from bacterially derived episomes resulted in stimulation of the interferon response, elevated DNA damage, and increased spontaneous differentiation. These cellular activities were diminished or absent in dbDNA-iPSCs, resulting in lines with a greater stability and safety potential for cell therapy.
The epidermis, the outer layer of the skin, relies on a delicate balance of cell growth and keratinocyte differentiation for its function and renewal. Recent research has shed light on exosomes’ role in facilitating skin communication by transferring molecules like miRNAs, which regulate gene expression post-transcriptionally. Additionally, these factors lead to skin aging through oxidative stress caused by reactive oxygen species (ROS). In this research project, experiments were conducted to study the impact of Sun2000 solar simulator irradiation on exosomal miRNA profiles in HEKa cells. We hypothesized that acute oxidative stress induced by solar simulator irradiation would alter the expression profile of exosomal miRNAs in HEKa cells. The cells were exposed to different durations of irradiation to induce oxidative stress, and the levels of reactive ROS were measured using the CellROX Deep Red flow cytometry assay kit. Exosomes were isolated from both control and irradiated cells, characterized using DLS and SEM techniques, and their miRNAs were extracted and analyzed using qPCR. Solar simulator irradiation led to a time-dependent increase in intracellular ROS and a decrease in cell viability. Exosomal size increased in irradiated cells. Fifty-nine exosomal miRNAs were differentially expressed in irradiated HEKa cells, including hsa-miR-425-5p, hsa-miR-181b-5p, hsa-miR-196b-5p, hsa-miR-376c-3p, and hsa-miR-15a-5p. This study highlights the significant impact of solar radiation on exosomal miRNA expression in keratinocytes, suggesting their potential role in the cellular response to oxidative stress.
Inherited biallelic mutations in the CLN7 gene result in the variant late infantile onset neuronal ceroid lipofuscinosis, a subtype of Batten disease (BD), a severe and fatal childhood neurodegenerative disease. Intriguingly, CLN7 genetic variants have also been associated with retinopathies, amyotrophic lateral sclerosis, and frontotemporal dementia. CLN7 encodes a transmembrane protein localizing to endolysosomal membranes with outward-facing chloride channel activity. Loss of CLN7 function results in cortical neurons accumulating swollen lipofuscin-containing lysosomes, leading to neuroinflammation and neurodegeneration. The molecular mechanisms underlying CLN7 BD neuropathology are not completely understood. We have generated iPSC lines from two CLN7 BD patients and age-matched unaffected controls to interrogate intracellular molecular phenotypes in iPSC-derived neural progenitor cells (iNPC). Taking a multi-omics approach we have identified disease-modified activities in endolysosomal transport in iNPC BD that lead to lysosomal dysfunction and decreased mitophagy, resulting in the accumulation of metabolically defective mitochondria. We further observe a breakdown in nuclear functions that centre on RNA processing and nuclear export, linking to CLN7 protein interactions at the stress granule. We have identified dual and distinct functions for CLN7, promoting cell survival during the cellular stress response. CLN7 loss of function in BD results in neuronal apoptosis.
Objectives: The purpose of this study was to assess the effects of self‐reported perception of facial and dental aesthetics on academic and social performance among dental students in Jordan. Methods: Online and paper‐based cross‐sectional surveys were collected from 371 dental students distributed between the two dental schools in Jordan. The survey contained the five sections of the Psychological Impact of Dental Aesthetics Questionnaire (PIDAQ), then asked participants about the presence or absence of factors that compromise dental aesthetics, and information about academic scores and academic satisfaction. Results: Results showed that facial and dental aesthetics had an impact on the social and academic performance of dental students in Jordan. Students who stated perceived factors compromising their dental aesthetics reported low levels of confidence when speaking and communicating with other people, lower grades, and low levels of satisfaction with overall academic performance. Conclusions: Social and academic performance of dental students in Jordan were found to be significantly influenced by the aesthetic qualities of the self‐reported facial and dental features. These findings highlight potential psychosocial impacts of perceived dental aesthetics, while acknowledging that other unmeasured factors may also contribute.