Applying genome-wide CRISPR-Cas9 screens for therapeutic discovery in facioscapulohumeral muscular dystrophy

The emergence of CRISPR-Cas9 gene-editing technologies and genome-wide CRISPR-Cas9 libraries enables efficient unbiased genetic screening that can accelerate the process of therapeutic discovery for genetic disorders. Here, we demonstrate the utility of a genome-wide CRISPR-Cas9 loss-of-function library to identify therapeutic targets for facioscapulohumeral muscular dystrophy (FSHD), a genetically complex type of muscular dystrophy for which there is currently no treatment. In FSHD, both genetic and epigenetic changes lead to misexpression of DUX4, the FSHD causal gene that encodes the highly cytotoxic DUX4 protein. We performed a genome-wide CRISPR-Cas9 screen to identify genes whose loss-of-function conferred survival when DUX4 was expressed in muscle cells. Genes emerging from our screen illuminated a pathogenic link to the cellular hypoxia response, which was revealed to be the main driver of DUX4-induced cell death. Application of hypoxia signaling inhibitors resulted in increased DUX4 protein turnover and subsequent reduction of the cellular hypoxia response and cell death. In addition, these compounds proved successful in reducing FSHD disease biomarkers in patient myogenic lines, as well as improving structural and functional properties in two zebrafish models of FSHD. Our genome-wide perturbation of pathways affecting DUX4 expression has provided insight into key drivers of DUX4-induced pathogenesis and has identified existing compounds with potential therapeutic benefit for FSHD. Our experimental approach presents an accelerated paradigm toward mechanistic understanding and therapeutic discovery of a complex genetic disease, which may be translatable to other diseases with well-established phenotypic selection assays.

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A Nonsense Variant in Hephaestin Like 1 (HEPHL1) Is Responsible for Congenital Hypotrichosis in Belted Galloway Cattle

Genes ◽

10.3390/genes12050643 ◽

2021 ◽

Vol 12 (5) ◽

pp. 643

Author(s):

Thibaud Kuca ◽

Brandy M. Marron ◽

Joana G. P. Jacinto ◽

Julia M. Paris ◽

Christian Gerspach ◽

...

Keyword(s):

Genome Wide Association Study ◽

Homozygosity Mapping ◽

Mendelian Inheritance ◽

Large Animal Model ◽

Large Animal ◽

Loss Of Function ◽

Protein Coding ◽

Positional Candidate ◽

Genome Wide ◽

A Genome

Genodermatosis such as hair disorders mostly follow a monogenic mode of inheritance. Congenital hypotrichosis (HY) belong to this group of disorders and is characterized by abnormally reduced hair since birth. The purpose of this study was to characterize the clinical phenotype of a breed-specific non-syndromic form of HY in Belted Galloway cattle and to identify the causative genetic variant for this recessive disorder. An affected calf born in Switzerland presented with multiple small to large areas of alopecia on the limbs and on the dorsal part of the head, neck, and back. A genome-wide association study using Swiss and US Belted Galloway cattle encompassing 12 cases and 61 controls revealed an association signal on chromosome 29. Homozygosity mapping in a subset of cases refined the HY locus to a 1.5 Mb critical interval and subsequent Sanger sequencing of protein-coding exons of positional candidate genes revealed a stop gain variant in the HEPHL1 gene that encodes a multi-copper ferroxidase protein so-called hephaestin like 1 (c.1684A>T; p.Lys562*). A perfect concordance between the homozygous presence of this most likely pathogenic loss-of-function variant and the HY phenotype was found. Genotyping of more than 700 purebred Swiss and US Belted Galloway cattle showed the global spread of the mutation. This study provides a molecular test that will permit the avoidance of risk matings by systematic genotyping of relevant breeding animals. This rare recessive HEPHL1-related form of hypotrichosis provides a novel large animal model for similar human conditions. The results have been incorporated in the Online Mendelian Inheritance in Animals (OMIA) database (OMIA 002230-9913).

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SEC24A identified as an essential mediator of thapsigargin-induced cell death in a genome-wide CRISPR/Cas9 screen

Cell Death Discovery ◽

10.1038/s41420-018-0135-5 ◽

2018 ◽

Vol 4 (1) ◽

Cited By ~ 6

Author(s):

Tamutenda Chidawanyika ◽

Elizabeth Sergison ◽

Michael Cole ◽

Kenneth Mark ◽

Surachai Supattapone

Keyword(s):

Cell Death ◽

Genome Wide ◽

A Genome

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Intracellular Staphylococcus aureus Perturbs the Host Cell Ca2+ Homeostasis To Promote Cell Death

mBio ◽

10.1128/mbio.02250-20 ◽

2020 ◽

Vol 11 (6) ◽

pp. e02250-20

Author(s):

Kathrin Stelzner ◽

Ann-Cathrin Winkler ◽

Chunguang Liang ◽

Aziza Boyny ◽

Carsten P. Ade ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Cell Death ◽

Host Cell ◽

Intracellular Bacterium ◽

Tissue Destruction ◽

Content Type ◽

Host Cell Death ◽

Genome Wide ◽

A Genome ◽

Spread Of Infection

ABSTRACTThe opportunistic human pathogen Staphylococcus aureus causes serious infectious diseases that range from superficial skin and soft tissue infections to necrotizing pneumonia and sepsis. While classically regarded as an extracellular pathogen, S. aureus is able to invade and survive within human cells. Host cell exit is associated with cell death, tissue destruction, and the spread of infection. The exact molecular mechanism employed by S. aureus to escape the host cell is still unclear. In this study, we performed a genome-wide small hairpin RNA (shRNA) screen and identified the calcium signaling pathway as being involved in intracellular infection. S. aureus induced a massive cytosolic Ca2+ increase in epithelial host cells after invasion and intracellular replication of the pathogen. This was paralleled by a decrease in endoplasmic reticulum Ca2+ concentration. Additionally, calcium ions from the extracellular space contributed to the cytosolic Ca2+ increase. As a consequence, we observed that the cytoplasmic Ca2+ rise led to an increase in mitochondrial Ca2+ concentration, the activation of calpains and caspases, and eventually to cell lysis of S. aureus-infected cells. Our study therefore suggests that intracellular S. aureus disturbs the host cell Ca2+ homeostasis and induces cytoplasmic Ca2+ overload, which results in both apoptotic and necrotic cell death in parallel or succession.IMPORTANCE Despite being regarded as an extracellular bacterium, the pathogen Staphylococcus aureus can invade and survive within human cells. The intracellular niche is considered a hideout from the host immune system and antibiotic treatment and allows bacterial proliferation. Subsequently, the intracellular bacterium induces host cell death, which may facilitate the spread of infection and tissue destruction. So far, host cell factors exploited by intracellular S. aureus to promote cell death are only poorly characterized. We performed a genome-wide screen and found the calcium signaling pathway to play a role in S. aureus invasion and cytotoxicity. The intracellular bacterium induces a cytoplasmic and mitochondrial Ca2+ overload, which results in host cell death. Thus, this study first showed how an intracellular bacterium perturbs the host cell Ca2+ homeostasis.

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DUX4 Signalling in the Pathogenesis of Facioscapulohumeral Muscular Dystrophy

International Journal of Molecular Sciences ◽

10.3390/ijms21030729 ◽

2020 ◽

Vol 21 (3) ◽

pp. 729 ◽

Cited By ~ 6

Author(s):

Kenji Rowel Q. Lim ◽

Quynh Nguyen ◽

Toshifumi Yokota

Keyword(s):

Skeletal Muscle ◽

Cell Death ◽

Transcription Factor ◽

Muscular Dystrophy ◽

Embryonic Development ◽

Disease Onset ◽

Facioscapulohumeral Muscular Dystrophy ◽

Signalling Pathways ◽

Progressive Muscle Weakness ◽

Homeobox Protein

Facioscapulohumeral muscular dystrophy (FSHD) is a disabling inherited muscular disorder characterized by asymmetric, progressive muscle weakness and degeneration. Patients display widely variable disease onset and severity, and sometimes present with extra-muscular symptoms. There is a consensus that FSHD is caused by the aberrant production of the double homeobox protein 4 (DUX4) transcription factor in skeletal muscle. DUX4 is normally expressed during early embryonic development, and is then effectively silenced in all tissues except the testis and thymus. Its reactivation in skeletal muscle disrupts numerous signalling pathways that mostly converge on cell death. Here, we review studies on DUX4-affected pathways in skeletal muscle and provide insights into how understanding these could help explain the unique pathogenesis of FSHD.

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Generation and Transcriptome Profiling of Slr1-d7 and Slr1-d8 Mutant Lines with a New Semi-Dominant Dwarf Allele of SLR1 Using the CRISPR/Cas9 System in Rice

International Journal of Molecular Sciences ◽

10.3390/ijms21155492 ◽

2020 ◽

Vol 21 (15) ◽

pp. 5492 ◽

Cited By ~ 1

Author(s):

Yu Jin Jung ◽

Jong Hee Kim ◽

Hyo Ju Lee ◽

Dong Hyun Kim ◽

Jihyeon Yu ◽

...

Keyword(s):

Gene Expression Analysis ◽

Transcriptome Profiling ◽

Rna Seq ◽

Loss Of Function ◽

Amino Acid Motif ◽

Dwarf Phenotype ◽

Genome Wide ◽

A Genome ◽

Mutant Lines ◽

Genome Wide Gene Expression

The rice SLR1 gene encodes the DELLA protein (protein with DELLA amino acid motif), and a loss-of-function mutation is dwarfed by inhibiting plant growth. We generate slr1-d mutants with a semi-dominant dwarf phenotype to target mutations of the DELLA/TVHYNP domain using CRISPR/Cas9 genome editing in rice. Sixteen genetic edited lines out of 31 transgenic plants were generated. Deep sequencing results showed that the mutants had six different mutation types at the target site of the TVHYNP domain of the SLR1 gene. The homo-edited plants selected individuals without DNA (T-DNA) transcribed by segregation in the T1 generation. The slr1-d7 and slr1-d8 plants caused a gibberellin (GA)-insensitive dwarf phenotype with shrunken leaves and shortened internodes. A genome-wide gene expression analysis by RNA-seq indicated that the expression levels of two GA-related genes, GA20OX2 (Gibberellin oxidase) and GA3OX2, were increased in the edited mutant plants, suggesting that GA20OX2 acts as a convert of GA12 signaling. These mutant plants are required by altering GA responses, at least partially by a defect in the phytohormone signaling system process and prevented cell elongation. The new mutants, namely, the slr1-d7 and slr1-d8 lines, are valuable semi-dominant dwarf alleles with potential application value for molecule breeding using the CRISPR/Cas9 system in rice.

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Identification and function of hypoxia-response genes in Drosophila melanogaster

Physiological Genomics ◽

10.1152/physiolgenomics.00262.2005 ◽

2006 ◽

Vol 25 (1) ◽

pp. 134-141 ◽

Cited By ~ 46

Author(s):

Guowen Liu ◽

Julianne Roy ◽

Eric A. Johnson

Keyword(s):

Recovery Time ◽

Normal Activity ◽

Mrna Levels ◽

Low Oxygen ◽

Hypoxia Response ◽

Oxygen Treatment ◽

Genome Wide ◽

A Genome ◽

And Function ◽

Genome Wide Study

Hypoxia, an insufficient level of oxygen in the cell, occurs during normal activity and also in pathological conditions such as ischemia and tumorigenesis. Although many hypoxia-response genes have been identified, an understanding of the functional role for these genes in the living animal is lacking. Here we present a genome-wide study of gene expression changes during hypoxia and then functionally test a subset of these genes for roles in survival and recovery from hypoxia. We found 79 genes with increased mRNA levels when adult flies were treated with 0.5% O2 for 6 h. A subset of these genes had detectably increased levels in as short as 1 h of low-oxygen treatment. Mild hypoxia levels resulted in an increase in transcription levels for only 20 genes. Viability during hypoxia and recovery time from hypoxia-induced paralysis was examined in flies with a reduction in activity in hypoxia-response genes. The observed decreased viability and increased recovery time from paralysis in many of the lines demonstrate that the increased transcript levels seen after hypoxia are important for the response to low oxygen.

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Identification of TMEM206 proteins as pore of PAORAC/ASOR acid-sensitive chloride channels

eLife ◽

10.7554/elife.49187 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 10

Author(s):

Florian Ullrich ◽

Sandy Blin ◽

Katina Lazarow ◽

Tony Daubitz ◽

Jens Peter von Kries ◽

...

Keyword(s):

Cell Death ◽

Plasma Membrane ◽

Ion Channels ◽

Gene Family ◽

Chloride Channels ◽

Anion Channel ◽

Ion Permeation ◽

Acid Sensing Ion Channels ◽

Genome Wide ◽

A Genome

Acid-sensing ion channels have important functions in physiology and pathology, but the molecular composition of acid-activated chloride channels had remained unclear. We now used a genome-wide siRNA screen to molecularly identify the widely expressed acid-sensitive outwardly-rectifying anion channel PAORAC/ASOR. ASOR is formed by TMEM206 proteins which display two transmembrane domains (TMs) and are expressed at the plasma membrane. Ion permeation-changing mutations along the length of TM2 and at the end of TM1 suggest that these segments line ASOR’s pore. While not belonging to a gene family, TMEM206 has orthologs in probably all vertebrates. Currents from evolutionarily distant orthologs share activation by protons, a feature essential for ASOR’s role in acid-induced cell death. TMEM206 defines a novel class of ion channels. Its identification will help to understand its physiological roles and the diverse ways by which anion-selective pores can be formed.

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CUX2 mutations in temporal lobe epilepsy; increased kainate susceptibility and excitatory input to hippocampus in deficient mice

10.1101/2021.09.17.460803 ◽

2021 ◽

Author(s):

Toshimitsu Suzuki ◽

Tetsuya Tatsukawa ◽

Genki Sudo ◽

Caroline Delandre ◽

Yun Jin Pai ◽

...

Keyword(s):

Synaptic Transmission ◽

Temporal Lobe Epilepsy ◽

Entorhinal Cortex ◽

Temporal Lobe ◽

Genome Wide Association Study ◽

De Novo ◽

Cell Number ◽

Loss Of Function ◽

Genome Wide ◽

A Genome

CUX2 gene encodes a transcription factor that controls neuronal proliferation, dendrite branching and synapse formation, locating at the epilepsy-associated chromosomal region 12q24 that we previously identified by a genome-wide association study (GWAS) in Japanese population. A CUX2 recurrent de novo variant p.E590K has been described in patients with rare epileptic encephalopathies and the gene is a candidate for the locus, however the mutation may not be enough to generate the genome-wide significance in the GWAS and whether CUX2 variants appear in other types of epilepsies and physiopathological mechanisms are remained to be investigated. Here in this study, we conducted targeted sequencings of CUX2, a paralog CUX1 and its short isoform CASP harboring a unique C-terminus on 271 Japanese patients with a variety of epilepsies, and found that multiple CUX2 missense variants, other than the p.E590K, and some CASP variants including a deletion, predominantly appeared in patients with temporal lobe epilepsy (TLE). Human cell culture and fly dendritic arborization analyses revealed loss-of- function properties for the CUX2 variants. Cux2- and Casp-specific knockout mice both showed high susceptibility to kainate, increased excitatory cell number in the entorhinal cortex, and significant enhancement in glutamatergic synaptic transmission to the hippocampus. CASP and CUX2 proteins physiologically bound to each other and co-expressed in excitatory neurons in brain regions including the entorhinal cortex. These results suggest that CUX2 and CASP variants contribute to the TLE pathology through a facilitation of excitatory synaptic transmission from entorhinal cortex to hippocampus.

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Identification of Genes Regulating Cell Death inStaphylococcus aureus

10.1101/569053 ◽

2019 ◽

Author(s):

Rebecca Yee ◽

Jie Feng ◽

Jiou Wang ◽

Jiazhen Chen ◽

Ying Zhang

Keyword(s):

Cell Death ◽

Acetic Acid ◽

Drug Targets ◽

Opportunistic Pathogen ◽

Infection Model ◽

Chronic Infections ◽

Bacterial Cell Death ◽

Genome Wide ◽

A Genome ◽

Genetic Mechanisms

AbstractStaphylococcus aureusis an opportunistic pathogen that causes acute and chronic infections. Due toS. aureus’ s highly resistant and persistent nature, it is paramount to identify better drug targets in order to eradicateS. aureusinfections. Despite the efforts in understanding bacterial cell death, the genes and pathways ofS. aureuscell death remain elusive. Here, we performed a genome-wide screen using a transposon mutant library to study the genetic mechanisms involved inS. aureuscell death. Using a precisely controlled heat-ramp and acetic acid exposure assays, mutations in 27 core genes (hsdR1, hslO, nsaS, sspA, folD, mfd, vraF, kdpB, USA300HOU_2684, 0868, 0369, 0420, 1154, 0142, 0930, 2590, 0997, 2559, 0044, 2004, 1209, 0152, 2455, 0154, 2386, 0232, 0350 involved in transporters, transcription, metabolism, peptidases, kinases, transferases, SOS response, nucleic acid and protein synthesis) caused the bacteria to be more death-resistant. In addition, we identified mutations in core 10 genes (capA, gltT, mnhG1,USA300HOU_1780, 2496, 0200, 2029, 0336, 0329, 2386, involved in transporters, metabolism, transcription, cell wall synthesis) from heat-ramp and acetic acid that caused the bacteria to be more death-sensitive or with defect in persistence. Interestingly, death-resistant mutants were more virulent than the parental strain USA300 and caused increased mortality in aCaenorhabditis elegansinfection model. Conversely, death-sensitive mutants were less persistent and formed less persister cells upon exposure to different classes of antibiotics. These findings provide new insights into the mechanisms ofS. aureuscell death and offer new therapeutic targets for developing more effective treatments caused byS. aureus.

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Genome-wide synthetic lethal CRISPR screen identifies FIS1 as a genetic interactor of ALS-linked C9ORF72

10.1101/778118 ◽

2019 ◽

Author(s):

Noori Chai ◽

Michael S. Haney ◽

Julien Couthouis ◽

David W. Morgens ◽

Alyssa Benjamin ◽

...

Keyword(s):

Genetic Interaction ◽

Mitochondrial Fission ◽

Loss Of Function ◽

Synthetic Lethal ◽

Genome Wide ◽

A Genome ◽

Crispr Screen ◽

Insight Into ◽

Mitochondrial Membrane Protein ◽

Lateral Sclerosis

AbstractMutations in the C9ORF72 gene are the most common cause of amyotrophic lateral sclerosis (ALS). Both toxic gain of function and loss of function pathogenic mechanisms have been proposed. Accruing evidence from mouse knockout studies point to a role for C9ORF72 as a regulator of immune function. To provide further insight into its cellular function, we performed a genome-wide synthetic lethal CRISPR screen in human myeloid cells lacking C9ORF72. We discovered a strong synthetic lethal genetic interaction between C9ORF72 and FIS1, which encodes a mitochondrial membrane protein involved in mitochondrial fission and mitophagy. Mass spectrometry experiments revealed that in C9ORF72 knockout cells, FIS1 strongly bound to a class of immune regulators that activate the receptor for advanced glycation end (RAGE) products and trigger inflammatory cascades. These findings present a novel genetic interactor for C9ORF72 and suggest a compensatory role for FIS1 in suppressing inflammatory signaling in the absence of C9ORF72.

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