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Bielczyk-Maczynska E, Sharma D, Blencowe M, Saliba Gustafsson P, Gloudemans MJ, Yang X, Carcamo-Orive I, Wabitsch M, Svensson KJ, Park CY, Quertermous T, Knowles JW, Li J. A single-cell CRISPRi platform for characterizing candidate genes relevant to metabolic disorders in human adipocytes. Am J Physiol Cell Physiol 2023; 325:C648-C660. [PMID: 37486064 PMCID: PMC10635647 DOI: 10.1152/ajpcell.00148.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/07/2023] [Accepted: 07/19/2023] [Indexed: 07/25/2023]
Abstract
CROP-Seq combines gene silencing using CRISPR interference with single-cell RNA sequencing. Here, we applied CROP-Seq to study adipogenesis and adipocyte biology. Human preadipocyte SGBS cell line expressing KRAB-dCas9 was transduced with a sgRNA library. Following selection, individual cells were captured using microfluidics at different timepoints during adipogenesis. Bioinformatic analysis of transcriptomic data was used to determine the knockdown effects, the dysregulated pathways, and to predict cellular phenotypes. Single-cell transcriptomes recapitulated adipogenesis states. For all targets, over 400 differentially expressed genes were identified at least at one timepoint. As a validation of our approach, the knockdown of PPARG and CEBPB (which encode key proadipogenic transcription factors) resulted in the inhibition of adipogenesis. Gene set enrichment analysis generated hypotheses regarding the molecular function of novel genes. MAFF knockdown led to downregulation of transcriptional response to proinflammatory cytokine TNF-α in preadipocytes and to decreased CXCL-16 and IL-6 secretion. TIPARP knockdown resulted in increased expression of adipogenesis markers. In summary, this powerful, hypothesis-free tool can identify novel regulators of adipogenesis, preadipocyte, and adipocyte function associated with metabolic disease.NEW & NOTEWORTHY Genomics efforts led to the identification of many genomic loci that are associated with metabolic traits, many of which are tied to adipose tissue function. However, determination of the causal genes, and their mechanism of action in metabolism, is a time-consuming process. Here, we use an approach to determine the transcriptional outcome of candidate gene knockdown for multiple genes at the same time in a human cell model of adipogenesis.
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Affiliation(s)
- Ewa Bielczyk-Maczynska
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, United States
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, California, United States
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California, United States
| | - Disha Sharma
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, United States
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California, United States
| | - Montgomery Blencowe
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California, United States
| | - Peter Saliba Gustafsson
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, United States
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, California, United States
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California, United States
- Cardiovascular Medicine Unit, Department of Medicine, Center for Molecular Medicine at BioClinicum, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Michael J Gloudemans
- Department of Pathology, Stanford University School of Medicine, Stanford, California, United States
- Biomedical Informatics Training Program, Stanford, California, United States
| | - Xia Yang
- Department of Integrative Biology and Physiology, University of California, Los Angeles, California, United States
| | - Ivan Carcamo-Orive
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, United States
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, California, United States
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California, United States
| | - Martin Wabitsch
- Department of Pediatrics and Adolescent Medicine, Center for Rare Endocrine Diseases, Division of Pediatric Endocrinology and Diabetes, Ulm University Medical Centre, Ulm, Germany
| | - Katrin J Svensson
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, California, United States
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California, United States
- Department of Pathology, Stanford University School of Medicine, Stanford, California, United States
| | - Chong Y Park
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, United States
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California, United States
| | - Thomas Quertermous
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, United States
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California, United States
| | - Joshua W Knowles
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, United States
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, California, United States
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California, United States
- Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California, United States
| | - Jiehan Li
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, United States
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, California, United States
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California, United States
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Identification of the ER-resident E3 ubiquitin ligase RNF145 as a novel LXR-regulated gene. PLoS One 2017; 12:e0172721. [PMID: 28231341 PMCID: PMC5322959 DOI: 10.1371/journal.pone.0172721] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/08/2017] [Indexed: 12/12/2022] Open
Abstract
Cellular cholesterol metabolism is subject to tight regulation to maintain adequate levels of this central lipid molecule. Herein, the sterol-responsive Liver X Receptors (LXRs) play an important role owing to their ability to reduce cellular cholesterol load. In this context, identifying the full set of LXR-regulated genes will contribute to our understanding of their role in cholesterol metabolism. Using global transcriptional analysis we report here the identification of RNF145 as an LXR-regulated target gene. We demonstrate that RNF145 is regulated by LXRs in both human and mouse primary cells and cell lines, and in vivo in mice. Regulation of RNF145 by LXR depends on a functional LXR-element in its proximal promotor. Consistent with LXR-dependent regulation of Rnf145 we show that regulation is lost in macrophages and fibroblasts from Lxrαβ(-/-) mice, and also in vivo in livers of Lxrα(-/-) mice treated with the LXR synthetic ligand T0901317. RNF145 is closely related to RNF139/TRC8, an E3 ligase implicated in control of SREBP processing. However, silencing of RNF145 in HepG2 or HeLa cells does not impair SREBP1/2 processing and sterol-responsive gene expression in these cells. Similar to TRC8, we demonstrate that RNF145 is localized to the ER and that it possesses intrinsic E3 ubiquitin ligase activity. In summary, we report the identification of RNF145 as an ER-resident E3 ubiquitin ligase that is transcriptionally controlled by LXR.
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