Impaired GSH biosynthesis disrupts eye development and PAX6 function
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ABSTRACT:
PROVIDER: PRJNA732284 | ENA |
REPOSITORIES: ENA
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Project description:Glutathione (GSH) is a critical endogenous antioxidant that protects against intracellular oxidative stress. As such, pathological alterations in GSH levels are linked to a myriad of diseases including cancer, neurodegeneration and cataract. The rate limiting step in GSH biosynthesis is catalyzed by the glutamate cysteine ligase catalytic subunit (GCLC). The high expression of GCLC in the lens supports the synthesis of millimolar concentrations of GSH in this tissue. Herein, we describe the morphological consequences of deleting (knocking out) Gclc from surface ectoderm-derived ocular tissues (using the Le-Cre transgene; Gclc KO) which includes an overt microphthalmia phenotype and severely disrupted formation of multiple ocular structures (i.e., cornea, iris, lens, retina). Controlling for the Le-Cre transgene revealed that the deletion of Gclc significantly exacerbated the microphthalmia phenotype in Le-Cre hemizygous mice and resulted in dysregulated gene expression that was unique to only the lenses of KO mice. We further characterized the impaired lens development by conducting an RNA-seq experiment on KO and Gclc control (CON) mouse lens at the day of birth. RNA-sequencing revealed significant differences between Gclc knockout (KO) and Gclc control (CON) lenses, including down-regulation of crystallins and lens fiber cell identity genes, and up-regulation of lens epithelial cell identity genes. In addition, genes related to the immune system (e.g., immune system process, inflammatory response, neutrophil chemotaxis) were upregulated, and genes related to eye/lens development were downregulated. TRANSFAC analysis of differentially expressed genes (DEGs) in the lens of Gclc KO mice implicated PAX6 as a key upstream regulator of Gclc KO sensitive genes. This was further supported by a strong positive correlation between the transcriptomes of the lenses of Gclc KO and Pax6 KO mice. Strikingly, the dysregulation of PAX6-regulated genes in Gclc KO mice was observed despite no change in the ocular localization of PAX6 or decrease in the expression of PAX6 in the lens. In vitro experiments demonstrated that suppression of intracellular GSH concentrations resulted in impairment of PAX6 transactivation activity. Taken together, the present results elucidate a novel mechanism wherein intracellular GSH concentrations may modulate PAX6 activity.
2021-08-23 | GSE175394 | GEO
Project description:PAX6, a paired box transcription factor, is necessary for eye development. However, how it regulates thecell identity of human corneal epithelial cells (CECs) is not well understood. We aimed to clarify thefunction of PAX6 in human CECs using gene knockout via the clustered regularly interspaced shortpalindromic repeats (CRISPR) and CRISPR associated protein 9 (Cas9) system. We designed guide RNAsfor different targets in PAX6. PAX6-depleted CECs maintained the epithelial morphology, but becamelarger. Global analyses using microarray revealed that down-regulated genes were primarily CEC-specificand included keratin 12, keratin 3, clusterin (CLU), aldehyde dehydrogenase 3 family member A1(ALDH3A1), angiopoietin-like 7 (ANGPTL7) and transketolase (TKT), while up-regulated genes wereprimarily epidermis-related and included keratin 10, keratin 1, involucrin (IVL), filaggrin (FLG). Thesefindings suggest that PAX6 maintains CEC identity by regulating differentiation.
2022-07-27 | GSE198924 | GEO
Project description:PAX6 is essential for eye and forebrain development but how PAX6 instructs retinal versus neuroectoderm specification remains unknown. We found that the paired-less PAX6, PAX6D, is uniquely expressed in retinal cells during human eye development and along human embryonic stem cell (hESC) differentiation to retinal cells. HESCs with deletion of PAX6D failed to enter retinal differentiation. Induced expression of PAX6D but not PAX6A under the PAX6-null background restored the retinal differentiation capacity. ChIP-Seq, confirmed by functional assays, revealed a set of retinal genes and neural genes that are targets of PAX6D, including WNT8B. Inhibition of WNTs restored the retinal differentiation capacity of neuroepithelia with PAX6D knockout whereas activation of WNTs blocks retinal differentiation even when PAX6D is induced. Thus, PAX6D specifies neuroepithelia to retinal cells, partly via regulation of WNTs.
2020-07-11 | GSE128140 | GEO
Project description:During organogenesis, PAX6 is required for establishment of various progenitor subtypes within the central nervous system, eye and pancreas. PAX6 expression is maintained in a variety of cell types within each organ, although its role in each lineage and how it acquires cell-specific activity remain elusive. Herein, we aimed to determine the roles and the hierarchical organization of the PAX6-dependent gene regulatory network during the differentiation of the retinal pigmented epithelium (RPE). Somatic mutagenesis of Pax6 in the differentiating RPE revealed that PAX6 functions in a feed-forward regulatory loop with MITF during onset of melanogenesis. PAX6 both controls the expression of an RPE isoform of Mitf and synergizes with MITF to activate expression of genes involved in pigment biogenesis. This study exemplifies how one kernel gene pivotal in organ formation accomplishes a lineage-specific role during terminal differentiation of a single lineage. The data contains 3 control and 3 Pax6 negative samples representing biological repeats. Each sample was prepared from RPE dissected from E15.5 transgenic animals, either Pax6loxP/loxP or Pax6loxP/loxP;DctCre.
2014-04-08 | E-GEOD-56548 | biostudies-arrayexpress
Project description:The essential thiol antioxidant, glutathione (GSH) is recruited into the nucleus of mammalian cells early in cell proliferation, suggesting a key role of the nuclear thiol pool in cell cycle regulation. However, the functions of nuclear GSH (GSHn) and its integration with the cytoplasmic GSH (GSHc) pools in whole cell redox homeostasis and signaling are unknown. Here we show that GSH is recruited into the nucleus early in cell proliferation in Arabidopsis thaliana, confirming the requirement for localization of GSH in the nucleus as a universal feature of cell cycle regulation. GSH accumulation in the nucleus was triggered by treatments that synchronize cells at G1/S as identified by flow cytometry and marker transcripts. Significant decreases in transcripts associated with oxidative signaling and stress tolerance occurred when GSH was localized in the nucleus. Increases in GSH1 and GSH2 transcripts accompanied the large increase in total cellular GSH observed during cell proliferation, but only GSH2 was differentially expressed in cells with high GSHn relative to those with an even intracellular distribution of GSH. Of the 7 Bcl-2 associated (BAG) genes in A. thaliana, only the nuclear-localized BAG 6 was differentially expressed in cells with high GSHn compared to GSHc. We conclude that GSHn is associated with decreased oxidative signaling and stress responses and that whole cell redox homeostasis is restored as the cell cycle progresses by enhanced GSH synthesis and accumulation in the cytoplasm. Arabidopsis cells were harvested at points during cell proliferation where GSH was localized either in the nucleus (GSHn) or where GSH was distributed throughout the cytoplasm (GSHc) for RNA extraction and hybridization on Affymetrix microarrays. We selected three stages where the GSH was into the nucleus and three stages where the GSH was distributed throughout the cells.
2010-02-27 | E-GEOD-20454 | biostudies-arrayexpress
Project description:Sox2 and Pax6 co-regulate genes in neural lineages and the eye by forming a ternary complex likely facilitated allosterically through DNA. We used the quantitative and scalable Cooperativity-by-sequencing (Coop-seq) approach to interrogate Sox2/Pax6 dimerization on a DNA library where five positions of the Pax6 half site are randomized yielding 1024 cooperativity factors. Consensus positions normally required for the high-affinity DNA binding by Pax6 need to be mutated for effective dimerization with Sox2. Out of the five randomized bases, a 5’ thymidin is present in most of the top ranking elements. However, according to structural models, this thymidin maps to a spacer region separating Sox and Pax half –sites and is not expected to directly interact with the binding proteins. Cooperative binding to the Coop-seq defined sequence signature was validated by classical EMSAs. Re-analysis of ChiPseq data identified several candidate elements in genomic regions co-bound by Sox2 and Pax6. A highly conserved Sox2/Pax6 bound site near the Sprouty2 locus consists of a prototype cooperativity signature. This element was verified to promote cooperative dimerization designating Sprouty2 as candidate target of Sox2/Pax6 in several mouse and human tissues including the brain and the eye. Collectively, the functional interplay of Sox2 and Pax6 demands the relaxation of high affinity binding sites and is enabled by alternative DNA sequences. We conclude that this binding mode evolved to warrant that a subset of target genes is only regulated in the presence of suitable partner factors.
2017-11-15 | GSE101529 | GEO
Project description:During organogenesis, PAX6 is required for establishment of various progenitor subtypes within the central nervous system, eye and pancreas. PAX6 expression is maintained in a variety of cell types within each organ, although its role in each lineage and how it acquires cell-specific activity remain elusive. Herein, we aimed to determine the roles and the hierarchical organization of the PAX6-dependent gene regulatory network during the differentiation of the retinal pigmented epithelium (RPE). Somatic mutagenesis of Pax6 in the differentiating RPE revealed that PAX6 functions in a feed-forward regulatory loop with MITF during onset of melanogenesis. PAX6 both controls the expression of an RPE isoform of Mitf and synergizes with MITF to activate expression of genes involved in pigment biogenesis. This study exemplifies how one kernel gene pivotal in organ formation accomplishes a lineage-specific role during terminal differentiation of a single lineage.
2014-04-08 | GSE56548 | GEO
Project description:GSH, being a versatile molecule, is actively involved in various bilogical processe of plant system. Our previous studies identifies an active role of GSH in plant defense signaling network. Here, we used microarray under GSH treated condition to obtain a global expression profiling under this altered GSH conditions. We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. A.thaliana, much accalimed model system of plant biology and being fully sequenced, we used this system to explore the specific relation of GSH with metabolic processes, phisiological conditions, etc.
2013-04-02 | E-GEOD-45677 | biostudies-arrayexpress
Project description:Enhancers play a critical role in development by precisely modulating spatial, temporal, and cell type-specific gene expression. Sequence variants in enhancers have been implicated in disease, however establishing the functional consequences of these variants is challenging due to a lack of understanding of precise cell types and developmental stages where the enhancers are normally active. PAX6 is the master regulator of eye development, with a regulatory landscape containing multiple enhancers driving expression in the eye. Whether these enhancers perform additive, redundant, or distinct functions is unknown. Here we describe the precise cell types and regulatory activity of two PAX6 retinal enhancers, HS5 and NRE. Using a unique combination of live imaging and single-cell RNA sequencing in dual enhancer-reporter zebrafish embryos, we uncover differences in the spatiotemporal activity of these enhancers. Our results show that although overlapping, these enhancers have distinct activities in different cell types and therefore likely non-redundant functions. This work demonstrates that unique cell type-specific activities can be uncovered for apparently similar enhancers when investigated at high resolution in vivo.
2023-08-24 | GSE240575 | GEO
Project description:PAX6 is an evolutionary conserved transcription factor important for normal development of the CNS, eye and pancreas. Its role in cancer is however poorly understood as both tumor suppressive- and oncogenic properties have been reported. We generated a pancreatic adenocarcinoma cell line (HPAFII) were PAX6 was knocked down by the use of short hairpin RNA. To generate a control cell line scrambled short hairpin RNA was used. Successful knock down of PAX6 was confirmed by RT-qPCR and Western blot. RNA were harvested from shPAX6, shControl and untransfected HPAFII cells, and used in gene expression microarray to look for differences in gene expression when PAX6 was knocked down.
2020-07-01 | E-MTAB-5416 | biostudies-arrayexpress