Transcriptomic Profiling of Small Molecule Atf6 Modulators in the Retina
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PROVIDER: PRJNA1224216 | ENA |
REPOSITORIES: ENA
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Project description:The Unfolded Protein Response (UPR) maintains endoplasmic reticulum (ER) homeostasis and is essential for retinal health. Activating Transcription Factor 6 (ATF6) controls a key UPR branch and upregulates genes that mitigate ER stress. Small molecule modulators of ATF6 have been characterized in cell culture models that increase or decrease the amount of the cleaved, transcriptional activator domain of ATF6 generated from the full-length precursor. However, the effects of these small molecule ATF6 modulators remains unclear in vivo, in part because of the lack of antibodies that robustly detect the cleaved, activated form of ATF6 in model organisms like mice. Here, we used targeted RNA sequencing (RNA-seq) to assess the transcriptional response to intraocular delivery of Ceapin-A7 (an ATF6 inhibitor) and AA147 (an ATF6 activator) in the mouse retina. Using this strategy, we demonstrate that Ceapin-A7 significantly suppressed ATF6 transcriptional targets, whereas AA147 induced ATF6-regulated genes in retinal tissue of the eye. We also show that neither small molecule ATF6 modulator caused retinal cell death, compromised vision, or triggered ER stress by histology, functional testing, and transcriptional analysis. These results identify a transcriptional strategy to sensitively detect and quantify Ceapin-A7 and AA147 modulation of ATF6 in vivo. These findings also identify non-toxic conditions for further in vivo evaluation of small molecule ATF6 modulators in mouse vision loss disease models linked to ER stress.
2025-08-19 | GSE289701 | GEO
Project description:The Unfolded Protein Response is a conserved intracellular signal transduction mechanism that maintains endoplasmic reticulum homeostasis and may contribute to the pathogenesis and progression of human diseases associated with ER stress. Genetic mutations in the UPR regulator, ATF6, lead to vision loss in heritable retinal diseases. Our prior studies found that disease mutations disrupt ATF6 function, but the pathomechanism by which loss of ATF6 activity causes vision loss in people is unknown. To investigate this, we developed retinal organoids from patient iPSCs carrying ATF6 disease mutations and from hESCs bearing CRISPR-edited ATF6 null alleles. Unexpectedly, we found that retinal organoids lacking functional ATF6 failed to form cone photoreceptors while rod photoreceptors were unaffected. We used adaptive optics imaging of the retinas in patients with ATF6 mutations and saw pronounced loss of cones and preservation of rods that closely mirrored our in vitro organoid phenotypes. Last, we found that a small molecule proteostasis agonist partially restored cone photoreceptor outer segment formation and gene expression in ATF6 mutant retinal organoids. Our results reveal a surprising and novel function for ATF6 in human cone photoreceptor development. Our findings identify a potential therapeutic strategy for patients based on small molecule reprogramming of the proteostasis network in the retina. Our study suggests that the UPR guides intrinsic developmental processes in specialized metazoan cell types in addition to its role in responding to extrinsic pathologic events.
2021-06-25 | GSE153302 | GEO
Project description:ATF6 encodes a transcription factor that is activated during the Unfolded Protein Response to protect cells from ER stress. Loss of ATF6α and its paralog ATF6β, results in embryonic lethality, notochord dysgenesis, and in people, loss of ATF6α specifically, results in malformed neuroretina and congenital vision loss. These phenotypes implicate an essential role for ATF6 during vertebrate development. We investigated the function of ATF6 in development using human stem cells undergoing differentiation into multipotent germ layers, nascent tissues, and organs. We artificially activated ATF6 in stem cells with a recently identified small molecule ATF6 agonist, and we inhibited ATF6 using iPSCs from patients harboring ATF6 mutations. We discovered that ATF6 suppresses pluripotency, enhances differentiation, and surprisingly, guides stem cells toward mesodermal cell fates. Our findings reveal a novel role for ATF6 during differentiation and identify a new strategy to robustly create mesodermal tissues through modulation of the ATF6 arm of the UPR.
2017-11-14 | GSE106847 | GEO
Project description:Pathological retinal neovascularization is a common mechanism for leading causes of vision loss including retinopathy of prematurity (ROP), diabetic retinopathy, and wet age-related macular degeneration. The Unfolded Protein Response (UPR) is an intracellular signal transduction mechanism controlled by the ER-resident proteins ATF6, IRE1, and PERK. In response to endoplasmic reticulum stress, UPR activates downstream transcriptional and translational programs that upregulate many proteins, including key angiogenesis factors like VEGF and HIF1a. This suggests an important role for UPR in developmental and pathologic retinal angiogenesis, but it is unclear which UPR regulatory genes are most important in these processes. Here, we focused on the role of Activating Transcription Factor 6 (ATF6) in pathologic and developmental retinal angiogenesis. We induced pathologic retinal neovascularization in Atf6-/- mice using the oxygen-induced retinopathy (OIR) model of ROP and examined functional, histologic, and molecular consequences in the retina. we found significantly preserved visual function, accompanied by decreased retinal neovascularization, endothelial cell proliferation, and UPR and angiogenesis transcriptional programs in Atf6-/- mice after OIR. When we chemically blocked ATF6 signaling by intraocular injection of the small molecule Ceapin-A7, we also saw suppression of UPR and angiogenesis gene expression. Last, we examined very young Atf6-/- mice when the inner retinal vasculature is developing and found a significant defect in pruning and blood vessel extension to the periphery at P7, but this delay was transient and Atf6-/- blood vessels fully recovered at older ages of development. Together, our results demonstrate ATF6’s critical role in developmental and pathological angiogenesis and highlight its potential as a therapeutic target to mitigate pathological retinal neovascularization.
2025-08-14 | GSE292097 | GEO
Project description:Disruption of alternative splicing frequently causes or contributes to human diseases and disorders. Consequently, there is a need for efficient and sensitive reporter assays capable of screening chemical libraries for compounds with efficacy in modulating important splicing events. Here, we describe a screening workflow employing dual Nano and Firefly luciferase alternative splicing reporters that affords highly efficient, sensitive, and linear detection of small molecule responses. Applying this system to a screen of ~95,000 small molecules, we identify compounds that selectively activate or repress a neuronal microexon network that is frequently disrupted in autism and overexpressed in neuroendocrine cancers. Remarkably, among the most potent and selective activating compounds are histone deacetylase (HDAC) inhibitors. We thus describe a high-throughput screening system for candidate splicing therapeutics, a resource of small molecule modulators of microexons, and insight into the mode of action and potential utility of HDAC inhibitors in the context of neurological disorders.
2024-05-28 | GSE228599 | GEO
Project description:The unfolded protein response maintains endoplasmic reticulum (ER) homeostasis by sensing protein-folding stress and orchestrating cellular adaptation via the ER-transmembrane proteins IRE1, PERK and ATF6. Malignant cells can co-opt IRE1 and PERK to sustain growth; however, the importance of ATF6 in cancer remains poorly deciphered. We observed elevated ATF6 transcriptional activity in several cancers including colorectal carcinoma (CRC). Genetic silencing or small molecule inhibition of ATF6 blocked cell cycle progression and reduced viability of several human CRC cell lines in vitro and disrupted tumor progression in vivo. Unexpectedly, ATF6 interference disabled Wnt and Myc signaling and reduced stemness. ATF6 inhibition attenuated growth of organoids derived from malignant but not normal human intestinal tissue, decreasing Wnt-pathway activity and driving cellular differentiation. Wnt-surrogate agonism in a Wnt-dependent CRC organoid restored pathway activity and rescued growth under ATF6 blockade. Our findings identify ATF6 as an unexpected facilitator of oncogenic Wnt signaling in CRC.
2024-08-06 | GSE273988 | GEO
Project description:The unfolded protein response maintains endoplasmic reticulum (ER) homeostasis by sensing protein-folding stress and orchestrating cellular adaptation via the ER-transmembrane proteins IRE1, PERK and ATF6. Malignant cells can co-opt IRE1 and PERK to sustain growth; however, the importance of ATF6 in cancer remains poorly deciphered. We observed elevated ATF6 transcriptional activity in several cancers including colorectal carcinoma (CRC). Genetic silencing or small molecule inhibition of ATF6 blocked cell cycle progression and reduced viability of several human CRC cell lines in vitro and disrupted tumor progression in vivo. Unexpectedly, ATF6 interference disabled Wnt and Myc signaling and reduced stemness. ATF6 inhibition attenuated growth of organoids derived from malignant but not normal human intestinal tissue, decreasing Wnt-pathway activity and driving cellular differentiation. Wnt-surrogate agonism in a Wnt-dependent CRC organoid restored pathway activity and rescued growth under ATF6 blockade. Our findings identify ATF6 as an unexpected facilitator of oncogenic Wnt signaling in CRC.
2024-08-08 | GSE274172 | GEO
Project description:Identifying brain-penetrant small-molecule modulators of human microglia using a cellular model of synaptic pruning
| PRJNA1265730 | ENA
Project description:The unfolded protein response (UPR) maintains endoplasmic reticulum (ER) homeostasis by sensing protein-folding stress and orchestrating cellular adaptation via the ER-transmembrane proteins IRE1, PERK and ATF6. Malignant cells can co-opt UPR signaling by IRE1 and PERK to sustain tumor growth; however, the importance of ATF6 in cancer remains poorly deciphered. We observed elevated ATF6 transcriptional activity in several cancers including colorectal carcinoma (CRC). Genetic silencing or small molecule inhibition of ATF6 blocked cell cycle progression and reduced viability of several human CRC cell lines in vitro and disrupted tumor progression in vivo. Unexpectedly, ATF6 interference also disabled Myc and Wnt signaling and reduced stemness. ATF6 inhibition attenuated growth of organoids derived from malignant but not normal human intestinal tissue, reducing Wnt-pathway activity and driving cellular differentiation. Wnt-surrogate agonism rescued the growth inhibitory phenotype of ATF6 interference. Our findings identify ATF6 as an unexpected facilitator of oncogenic Wnt signaling in CRC.
2024-08-12 | MSV000095581 | MassIVE
Project description:Achromatopsia (ACHM) is an autosomal recessive disease that results in severe visual loss. Symptoms of ACHM include impaired visual acuity, nystagmus, and photoaversion starting from infancy; furthermore, ACHM is associated with bilateral foveal hypoplasia and absent or severely reduced cone photoreceptor function on electroretinography. Here, we performed genetic sequencing in 3 patients from 2 families with ACHM, identifying and functionally characterizing 2 mutations in the activating transcription factor 6 (ATF6) gene. We identified a homozygous deletion covering exons 8–14 of the ATF6 gene from 2 siblings from the same family. In another patient from a different family, we identified a heterozygous deletion covering exons 2 and 3 of the ATF6 gene found in trans with a previously identified ATF6 c.970C>T (p.Arg324Cys) ACHM disease allele. Recombinant ATF6 proteins bearing these exon deletions showed markedly impaired transcriptional activity by qPCR and RNA-Seq analysis compared with WT-ATF6. Finally, RNAscope revealed that ATF6 and the related ATF6B transcripts were expressed in cones as well as in all retinal layers in normal human retina. Overall, our data identify loss-of-function ATF6 disease alleles that cause human foveal disease.
2020-07-08 | GSE153978 | GEO