1
|
Rosarda JD, Giles S, Harkins-Perry S, Mills EA, Friedlander M, Wiseman RL, Eade KT. Imbalanced unfolded protein response signaling contributes to 1-deoxysphingolipid retinal toxicity. Nat Commun 2023; 14:4119. [PMID: 37433773 DOI: 10.1038/s41467-023-39775-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 06/23/2023] [Indexed: 07/13/2023] Open
Abstract
The accumulation of atypical, cytotoxic 1-deoxysphingolipids (1-dSLs) has been linked to retinal diseases such as diabetic retinopathy and Macular Telangiectasia Type 2. However, the molecular mechanisms by which 1-dSLs induce toxicity in retinal cells remain poorly understood. Here, we integrate bulk and single-nucleus RNA-sequencing to define biological pathways that modulate 1-dSL toxicity in human retinal organoids. Our results demonstrate that 1-dSLs differentially activate signaling arms of the unfolded protein response (UPR) in photoreceptor cells and Müller glia. Using a combination of pharmacologic activators and inhibitors, we show that sustained PERK signaling through the integrated stress response (ISR) and deficiencies in signaling through the protective ATF6 arm of the UPR are implicated in 1-dSL-induced photoreceptor toxicity. Further, we demonstrate that pharmacologic activation of ATF6 mitigates 1-dSL toxicity without impacting PERK/ISR signaling. Collectively, our results identify new opportunities to intervene in 1-dSL linked diseases through targeting different arms of the UPR.
Collapse
Affiliation(s)
- Jessica D Rosarda
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Sarah Giles
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
- Lowy Medical Research Institute, La Jolla, CA, 92037, USA
| | - Sarah Harkins-Perry
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
- Lowy Medical Research Institute, La Jolla, CA, 92037, USA
| | - Elizabeth A Mills
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
- Lowy Medical Research Institute, La Jolla, CA, 92037, USA
| | - Martin Friedlander
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
- Lowy Medical Research Institute, La Jolla, CA, 92037, USA
| | - R Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Kevin T Eade
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA.
- Lowy Medical Research Institute, La Jolla, CA, 92037, USA.
| |
Collapse
|
2
|
Usui-Ouchi A, Giles S, Harkins-Perry S, Mills EA, Bonelli R, Wei G, Ouchi Y, Ebihara N, Nakao S, Friedlander M, Eade KT. Integrating human iPSC-derived macrophage progenitors into retinal organoids to generate a mature retinal microglial niche. Glia 2023. [PMID: 37335016 DOI: 10.1002/glia.24428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/21/2023]
Abstract
In the retina, microglia are resident immune cells that are essential for development and function. Retinal microglia play a central role in mediating pathological degeneration in diseases such as glaucoma, retinitis pigmentosa, age-related neurodegeneration, ischemic retinopathy, and diabetic retinopathy. Current models of mature human retinal organoids (ROs) derived from iPS cell (hiPSC) do not contain resident microglia integrated into retinal layers. Increasing cellular diversity in ROs by including resident microglia would more accurately represent the native retina and better model diseases in which microglia play a key role. In this study, we develop a new 3D in vitro tissue model of microglia-containing retinal organoids by co-culturing ROs and hiPSC-derived macrophage precursor cells (MPCs). We optimized the parameters for successful integration of MPCs into retinal organoids. We show that while in the ROs, MPCs migrate to the equivalent of the outer plexiform layer where retinal microglia cells reside in healthy retinal tissue. While there, they develop a mature morphology characterized by small cell bodies and long branching processes which is only observed in vivo. During this maturation process these MPCs cycle through an activated phase followed by a stable mature microglial phase as seen by the down regulation of pro-inflammatory cytokines and upregulation of anti-inflammatory cytokines. Finally, we characterized mature ROs with integrated MPCs using RNAseq showing an enrichment of cell-type specific microglia markers. We propose that this co-culture system may be useful for understanding the pathogenesis of retinal diseases involving retinal microglia and for drug discovery directly in human tissue.
Collapse
Affiliation(s)
- Ayumi Usui-Ouchi
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
- Department of Ophthalmology, Juntendo University Urayasu Hospital, Urayasu, Japan
| | - Sarah Giles
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
- The Lowy Medical Research Institute, La Jolla, California, USA
| | - Sarah Harkins-Perry
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
- The Lowy Medical Research Institute, La Jolla, California, USA
| | | | - Roberto Bonelli
- The Lowy Medical Research Institute, La Jolla, California, USA
| | - Guoqin Wei
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Yasuo Ouchi
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, California, USA
- Department of Regenerative Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Nobuyuki Ebihara
- Department of Ophthalmology, Juntendo University Urayasu Hospital, Urayasu, Japan
| | - Shintaro Nakao
- Department of Ophthalmology, Juntendo University, Tokyo, Japan
| | - Martin Friedlander
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
- The Lowy Medical Research Institute, La Jolla, California, USA
| | - Kevin T Eade
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
- The Lowy Medical Research Institute, La Jolla, California, USA
| |
Collapse
|
3
|
Eade KT, Ansell BRE, Giles S, Fallon R, Harkins-Perry S, Nagasaki T, Tzaridis S, Wallace M, Mills EA, Farashi S, Johnson A, Sauer L, Hart B, Diaz-Rubio ME, Bahlo M, Metallo C, Allikmets R, Gantner ML, Bernstein PS, Friedlander M. iPSC-derived retinal pigmented epithelial cells from patients with macular telangiectasia show decreased mitochondrial function. J Clin Invest 2023; 133:e163771. [PMID: 37115691 PMCID: PMC10145939 DOI: 10.1172/jci163771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 03/14/2023] [Indexed: 04/29/2023] Open
Abstract
Patient-derived induced pluripotent stem cells (iPSCs) provide a powerful tool for identifying cellular and molecular mechanisms of disease. Macular telangiectasia type 2 (MacTel) is a rare, late-onset degenerative retinal disease with an extremely heterogeneous genetic architecture, lending itself to the use of iPSCs. Whole-exome sequencing screens and pedigree analyses have identified rare causative mutations that account for less than 5% of cases. Metabolomic surveys of patient populations and GWAS have linked MacTel to decreased circulating levels of serine and elevated levels of neurotoxic 1-deoxysphingolipids (1-dSLs). However, retina-specific, disease-contributing factors have yet to be identified. Here, we used iPSC-differentiated retinal pigmented epithelial (iRPE) cells derived from donors with or without MacTel to screen for novel cell-intrinsic pathological mechanisms. We show that MacTel iRPE cells mimicked the low serine levels observed in serum from patients with MacTel. Through RNA-Seq and gene set enrichment pathway analysis, we determined that MacTel iRPE cells are enriched in cellular stress pathways and dysregulation of central carbon metabolism. Using respirometry and mitochondrial stress testing, we functionally validated that MacTel iRPE cells had a reduction in mitochondrial function that was independent of defects in serine biosynthesis and 1-dSL accumulation. Thus, we identified phenotypes that may constitute alternative disease mechanisms beyond the known serine/sphingolipid pathway.
Collapse
Affiliation(s)
- Kevin T. Eade
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Brendan Robert E. Ansell
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Sarah Giles
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Regis Fallon
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Sarah Harkins-Perry
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Takayuki Nagasaki
- Department of Ophthalmology and
- Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Simone Tzaridis
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Martina Wallace
- Institute of Food and Health, School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Elizabeth A. Mills
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Samaneh Farashi
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Alec Johnson
- The Lowy Medical Research Institute, La Jolla, California, USA
| | - Lydia Sauer
- Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Barbara Hart
- Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - M. Elena Diaz-Rubio
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, USA
| | - Melanie Bahlo
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Christian Metallo
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, USA
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
| | - Rando Allikmets
- Department of Ophthalmology and
- Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Marin L. Gantner
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| | - Paul S. Bernstein
- Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Martin Friedlander
- The Lowy Medical Research Institute, La Jolla, California, USA
- Department of Molecular Medicine, The Scripps Research Institute (TSRI), La Jolla, California, USA
| |
Collapse
|
4
|
Tsunemoto RK, Eade KT, Blanchard JW, Baldwin KK. Forward engineering neuronal diversity using direct reprogramming. EMBO J 2015; 34:1445-55. [PMID: 25908841 PMCID: PMC4474523 DOI: 10.15252/embj.201591402] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 03/24/2015] [Indexed: 01/03/2023] Open
Abstract
The nervous system is comprised of a vast diversity of distinct neural cell types. Differences between neuronal subtypes drive the assembly of neuronal circuits and underlie the subtype specificity of many neurological diseases. Yet, because neurons are irreversibly post-mitotic and not readily available from patients, it has not been feasible to study specific subtypes of human neurons in larger numbers. A powerful means to study neuronal diversity and neurological disease is to establish methods to produce desired neuronal subtypes in vitro. Traditionally this has been accomplished by treating pluripotent or neural stem cells with growth factors and morphogens that recapitulate exogenous developmental signals. These approaches often require extended periods of culture, which can limit their utility. However, more recently, it has become possible to produce neurons directly from fibroblasts using transcription factors and/or microRNAs. This technique referred to as direct reprogramming or transdifferentiation has proven to be a rapid, robust, and reproducible method to generate mature neurons of many different subtypes from multiple cell sources. Here, we highlight recent advances in generating neurons of specific subtypes using direct reprogramming and outline various scenarios in which induced neurons may be applied to studies of neuronal function and neurological disease.
Collapse
Affiliation(s)
| | - Kevin T Eade
- The Scripps Research Institute, La Jolla, CA, USA
| | | | | |
Collapse
|
5
|
Eade KT, Fancher HA, Ridyard MS, Allan DW. Developmental transcriptional networks are required to maintain neuronal subtype identity in the mature nervous system. PLoS Genet 2012; 8:e1002501. [PMID: 22383890 PMCID: PMC3285578 DOI: 10.1371/journal.pgen.1002501] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 12/09/2011] [Indexed: 11/30/2022] Open
Abstract
During neurogenesis, transcription factors combinatorially specify neuronal fates and then differentiate subtype identities by inducing subtype-specific gene expression profiles. But how is neuronal subtype identity maintained in mature neurons? Modeling this question in two Drosophila neuronal subtypes (Tv1 and Tv4), we test whether the subtype transcription factor networks that direct differentiation during development are required persistently for long-term maintenance of subtype identity. By conditional transcription factor knockdown in adult Tv neurons after normal development, we find that most transcription factors within the Tv1/Tv4 subtype transcription networks are indeed required to maintain Tv1/Tv4 subtype-specific gene expression in adults. Thus, gene expression profiles are not simply “locked-in,” but must be actively maintained by persistent developmental transcription factor networks. We also examined the cross-regulatory relationships between all transcription factors that persisted in adult Tv1/Tv4 neurons. We show that certain critical cross-regulatory relationships that had existed between these transcription factors during development were no longer present in the mature adult neuron. This points to key differences between developmental and maintenance transcriptional regulatory networks in individual neurons. Together, our results provide novel insight showing that the maintenance of subtype identity is an active process underpinned by persistently active, combinatorially-acting, developmental transcription factors. These findings have implications for understanding the maintenance of all long-lived cell types and the functional degeneration of neurons in the aging brain. For neurons to function properly, they must establish and then maintain their unique, subtype-specific gene expression profiles. These unique gene expression profiles are established during development by networks of DNA–binding proteins, termed transcription factors (TFs). However, how neurons maintain their unique gene expression profiles in the mature and aging brain is largely unknown. Recent advances in inducible genetic technologies now allow us to manipulate gene expression in adult neurons, after normal development. Applying such techniques, we examined the effect of knocking down TF expression in two adult neuronal subtypes. We show that the TF networks that establish unique gene expression profiles during development are then required to maintain them thereafter. Thus, gene expression profiles are not simply “locked-in,” but must be actively maintained by persistent developmental TF networks. However, we found that critical cross-regulatory relationships that had existed between TFs during development were not present in the adult, even between persisting TFs. This highlights important differences between developmental and maintenance transcriptional networks in individual neurons. The dependence of subtype gene expression on active mechanisms represents a potential Achilles heel for long-lived cells, as deterioration of those active mechanisms could lead to functional degeneration of neurons with advancing age.
Collapse
Affiliation(s)
- Kevin T. Eade
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Hailey A. Fancher
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Marc S. Ridyard
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Douglas W. Allan
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
- * E-mail:
| |
Collapse
|