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Caothien R, Yu C, Tam L, Newman R, Nakao B, Alcantar T, Bacarro N, Reyes J, Pham A, Roose-Girma M. Accelerated embryonic stem cell screening with a highly efficient genotyping pipeline. Mol Biol Rep 2022; 49:3281-3288. [PMID: 35107736 DOI: 10.1007/s11033-022-07165-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 01/19/2022] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Gene targeting in mouse ES cells replaces or modifies genes of interest; conditional alleles, reporter knock-ins, and amino acid changes are common examples of how gene targeting is used. For example, enhanced green fluorescent protein or Cre recombinase is placed under the control of endogenous genes to define promoter expression patterns. METHODS AND RESULTS The most important step in the process is to demonstrate that a gene targeting vector is correctly integrated in the genome at the desired chromosomal location. The rapid identification of correctly targeted ES cell clones is facilitated by proper targeting vector construction, rapid screening procedures, and advances in cell culture. Here, we optimized and functionally linked magnetic activated cell sorting (MACS) technology as well as multiplex droplet digital PCR (ddPCR) to our ES cell screening process to achieve a greater than 60% assurance that ES clones are correctly targeted. In a further refinement of the process, drug selection cassettes are removed from ES cells with adenovirus technology. We describe this improved workflow and illustrate the reduction in time between therapeutic target identification and experimental validation. CONCLUSION In sum, we describe a novel and effective implementation of ddPCR, multiMACS, and adenovirus recombinase into a streamlined screening workflow that significantly reduces timelines for gene targeting in mouse ES cells.
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Affiliation(s)
- Roger Caothien
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Charles Yu
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Lucinda Tam
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Robert Newman
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Brian Nakao
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Tuija Alcantar
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Natasha Bacarro
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Juan Reyes
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Anna Pham
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Merone Roose-Girma
- Department of Molecular Biology, Genentech, Inc., South San Francisco, CA, USA.
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LRRC15 + myofibroblasts dictate the stromal setpoint to suppress tumour immunity. Nature 2022; 611:148-154. [PMID: 36171287 PMCID: PMC9630141 DOI: 10.1038/s41586-022-05272-1] [Citation(s) in RCA: 114] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 08/24/2022] [Indexed: 12/20/2022]
Abstract
Recent single-cell studies of cancer in both mice and humans have identified the emergence of a myofibroblast population specifically marked by the highly restricted leucine-rich-repeat-containing protein 15 (LRRC15)1-3. However, the molecular signals that underlie the development of LRRC15+ cancer-associated fibroblasts (CAFs) and their direct impact on anti-tumour immunity are uncharacterized. Here in mouse models of pancreatic cancer, we provide in vivo genetic evidence that TGFβ receptor type 2 signalling in healthy dermatopontin+ universal fibroblasts is essential for the development of cancer-associated LRRC15+ myofibroblasts. This axis also predominantly drives fibroblast lineage diversity in human cancers. Using newly developed Lrrc15-diphtheria toxin receptor knock-in mice to selectively deplete LRRC15+ CAFs, we show that depletion of this population markedly reduces the total tumour fibroblast content. Moreover, the CAF composition is recalibrated towards universal fibroblasts. This relieves direct suppression of tumour-infiltrating CD8+ T cells to enhance their effector function and augments tumour regression in response to anti-PDL1 immune checkpoint blockade. Collectively, these findings demonstrate that TGFβ-dependent LRRC15+ CAFs dictate the tumour-fibroblast setpoint to promote tumour growth. These cells also directly suppress CD8+ T cell function and limit responsiveness to checkpoint blockade. Development of treatments that restore the homeostatic fibroblast setpoint by reducing the population of pro-disease LRRC15+ myofibroblasts may improve patient survival and response to immunotherapy.
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Adams EJ, Khoriaty R, Kiseleva A, Cleuren ACA, Tomberg K, van der Ent MA, Gergics P, Tang VT, Zhu G, Hoenerhoff MJ, O'Shea KS, Saunders TL, Ginsburg D. Murine SEC24D can substitute functionally for SEC24C during embryonic development. Sci Rep 2021; 11:21100. [PMID: 34702932 PMCID: PMC8548507 DOI: 10.1038/s41598-021-00579-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 10/07/2021] [Indexed: 11/30/2022] Open
Abstract
The COPII component SEC24 mediates the recruitment of transmembrane cargos or cargo adaptors into newly forming COPII vesicles on the ER membrane. Mammalian genomes encode four Sec24 paralogs (Sec24a-d), with two subfamilies based on sequence homology (SEC24A/B and C/D), though little is known about their comparative functions and cargo-specificities. Complete deficiency for Sec24d results in very early embryonic lethality in mice (before the 8 cell stage), with later embryonic lethality (E7.5) observed in Sec24c null mice. To test the potential overlap in function between SEC24C/D, we employed dual recombinase mediated cassette exchange to generate a Sec24cc-d allele, in which the C-terminal 90% of SEC24C has been replaced by SEC24D coding sequence. In contrast to the embryonic lethality at E7.5 of SEC24C-deficiency, Sec24cc-d/c-d pups survive to term, though dying shortly after birth. Sec24cc-d/c-d pups are smaller in size, but exhibit no other obvious developmental abnormality by pathologic evaluation. These results suggest that tissue-specific and/or stage-specific expression of the Sec24c/d genes rather than differences in cargo export function explain the early embryonic requirements for SEC24C and SEC24D.
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Affiliation(s)
- Elizabeth J Adams
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, 48109, USA
- Constellation Pharmaceuticals, Cambridge, MA, 02142, USA
| | - Rami Khoriaty
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
- Univeristy of Michigan Rogel Cancer Center, Ann Arbor, MI, 48109, USA.
| | - Anna Kiseleva
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Audrey C A Cleuren
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Kärt Tomberg
- Departement of Human Genetics, University of Michigan, Ann Arbor, MI, 48109, USA
| | | | - Peter Gergics
- Departement of Human Genetics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Vi T Tang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Guojing Zhu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Mark J Hoenerhoff
- In Vivo Animal Core, Unit of Laboratory Animal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - K Sue O'Shea
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Thomas L Saunders
- Transgenic Animal Model Core, University of Michigan, Ann Arbor, MI, 48109, USA
| | - David Ginsburg
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA.
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, 48109, USA.
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, 48109, USA.
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Cross-tissue organization of the fibroblast lineage. Nature 2021; 593:575-579. [PMID: 33981032 DOI: 10.1038/s41586-021-03549-5] [Citation(s) in RCA: 406] [Impact Index Per Article: 135.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 04/13/2021] [Indexed: 02/06/2023]
Abstract
Fibroblasts are non-haematopoietic structural cells that define the architecture of organs, support the homeostasis of tissue-resident cells and have key roles in fibrosis, cancer, autoimmunity and wound healing1. Recent studies have described fibroblast heterogeneity within individual tissues1. However, the field lacks a characterization of fibroblasts at single-cell resolution across tissues in healthy and diseased organs. Here we constructed fibroblast atlases by integrating single-cell transcriptomic data from about 230,000 fibroblasts across 17 tissues, 50 datasets, 11 disease states and 2 species. Mouse fibroblast atlases and a DptIRESCreERT2 knock-in mouse identified two universal fibroblast transcriptional subtypes across tissues. Our analysis suggests that these cells can serve as a reservoir that can yield specialized fibroblasts across a broad range of steady-state tissues and activated fibroblasts in disease. Comparison to an atlas of human fibroblasts from perturbed states showed that fibroblast transcriptional states are conserved between mice and humans, including universal fibroblasts and activated phenotypes associated with pathogenicity in human cancer, fibrosis, arthritis and inflammation. In summary, a cross-species and pan-tissue approach to transcriptomics at single-cell resolution has identified key organizing principles of the fibroblast lineage in health and disease.
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PD-L1 expression by dendritic cells is a key regulator of T-cell immunity in cancer. ACTA ACUST UNITED AC 2020; 1:681-691. [DOI: 10.1038/s43018-020-0075-x] [Citation(s) in RCA: 137] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 05/13/2020] [Indexed: 12/12/2022]
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Hair Cell Loss, Spiral Ganglion Degeneration, and Progressive Sensorineural Hearing Loss in Mice with Targeted Deletion of Slc44a2/Ctl2. J Assoc Res Otolaryngol 2016; 16:695-712. [PMID: 26463873 PMCID: PMC4636594 DOI: 10.1007/s10162-015-0547-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 10/01/2015] [Indexed: 11/05/2022] Open
Abstract
SLC44A2 (solute carrier 44a2), also known as CTL2 (choline transporter-like protein 2), is expressed in many supporting cell types in the cochlea and is implicated in hair cell survival and antibody-induced hearing loss. In mice with the mixed C57BL/6-129 background, homozygous deletion of Slc44a2 exons 3–10 (Slc44a2Δ/Δ) resulted in high-frequency hearing loss and hair cell death. To reduce effects associated with age-related hearing loss (ARHL) in these strains, mice carrying the Slc44a2Δ allele were backcrossed to the ARHL-resistant FVB/NJ strain and evaluated after backcross seven (N7) (99 % FVB). Slc44a2Δ/Δ mice produced abnormally spliced Slc44a2 transcripts that contain a frameshift and premature stop codons. Neither full-length SLC44A2 nor a putative truncated protein could be detected in Slc44a2Δ/Δ mice, suggesting a likely null allele. Auditory brain stem responses (ABRs) of mice carrying the Slc44a2Δ allele on an FVB/NJ genetic background were tested longitudinally between the ages of 2 and 10 months. By 6 months of age, Slc44a2Δ/Δ mice exhibited hearing loss at 32 kHz, but at 12 and 24 kHz had sound thresholds similar to those of wild-type Slc44a2+/+ and heterozygous +/Slc44a2Δ mice. After 6 months of age, Slc44a2Δ/Δ mutants exhibited progressive hearing loss at all frequencies and +/Slc44a2Δ mice exhibited moderate threshold elevations at high frequency. Histologic evaluation of Slc44a2Δ/Δ mice revealed extensive hair cell and spiral ganglion cell loss, especially in the basal turn of the cochlea. We conclude that Slc44a2 function is required for long-term hair cell survival and maintenance of hearing.
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Menezes ME, Das SK, Emdad L, Windle JJ, Wang XY, Sarkar D, Fisher PB. Genetically engineered mice as experimental tools to dissect the critical events in breast cancer. Adv Cancer Res 2014; 121:331-382. [PMID: 24889535 PMCID: PMC4349377 DOI: 10.1016/b978-0-12-800249-0.00008-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Elucidating the mechanism of pathogenesis of breast cancer has greatly benefited from breakthrough advances in both genetically engineered mouse (GEM) models and xenograft transplantation technologies. The vast array of breast cancer mouse models currently available is testimony to the complexity of mammary tumorigenesis and attempts by investigators to accurately portray the heterogeneity and intricacies of this disease. Distinct molecular changes that drive various aspects of tumorigenesis, such as alterations in tumor cell proliferation and apoptosis, invasion and metastasis, angiogenesis, and drug resistance have been evaluated using the currently available GEM breast cancer models. GEM breast cancer models are also being exploited to evaluate and validate the efficacy of novel therapeutics, vaccines, and imaging modalities for potential use in the clinic. This review provides a synopsis of the various GEM models that are expanding our knowledge of the nuances of breast cancer development and progression and can be instrumental in the development of novel prevention and therapeutic approaches for this disease.
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Affiliation(s)
- Mitchell E Menezes
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Swadesh K Das
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Luni Emdad
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Jolene J Windle
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Xiang-Yang Wang
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Devanand Sarkar
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Paul B Fisher
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA.
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Lehoczky JA, Thomas PE, Patrie KM, Owens KM, Villarreal LM, Galbraith K, Washburn J, Johnson CN, Gavino B, Borowsky AD, Millen KJ, Wakenight P, Law W, Van Keuren ML, Gavrilina G, Hughes ED, Saunders TL, Brihn L, Nadeau JH, Innis JW. A novel intergenic ETnII-β insertion mutation causes multiple malformations in polypodia mice. PLoS Genet 2013; 9:e1003967. [PMID: 24339789 PMCID: PMC3854779 DOI: 10.1371/journal.pgen.1003967] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 10/04/2013] [Indexed: 11/28/2022] Open
Abstract
Mouse early transposon insertions are responsible for ∼10% of spontaneous mutant phenotypes. We previously reported the phenotypes and genetic mapping of Polypodia, (Ppd), a spontaneous, X-linked dominant mutation with profound effects on body plan morphogenesis. Our new data shows that mutant mice are not born in expected Mendelian ratios secondary to loss after E9.5. In addition, we refined the Ppd genetic interval and discovered a novel ETnII-β early transposon insertion between the genes for Dusp9 and Pnck. The ETn inserted 1.6 kb downstream and antisense to Dusp9 and does not disrupt polyadenylation or splicing of either gene. Knock-in mice engineered to carry the ETn display Ppd characteristic ectopic caudal limb phenotypes, showing that the ETn insertion is the Ppd molecular lesion. Early transposons are actively expressed in the early blastocyst. To explore the consequences of the ETn on the genomic landscape at an early stage of development, we compared interval gene expression between wild-type and mutant ES cells. Mutant ES cell expression analysis revealed marked upregulation of Dusp9 mRNA and protein expression. Evaluation of the 5′ LTR CpG methylation state in adult mice revealed no correlation with the occurrence or severity of Ppd phenotypes at birth. Thus, the broad range of phenotypes observed in this mutant is secondary to a novel intergenic ETn insertion whose effects include dysregulation of nearby interval gene expression at early stages of development. Mobile genetic elements, particularly early transposons (ETn), cause malformations by inserting within genes leading to disruption of exons, splicing or polyadenylation. Few mutagenic early transposon insertions have been found outside genes and the effects of such insertions on surrounding gene regulation is poorly understood. We discovered a novel intergenic ETnII-β insertion in the mouse mutant Polypodia (Ppd). We reproduced the mutant phenotype after engineering the mutation in wild-type cells with homologous recombination, proving that this early transposon insertion is Ppd. Mutant mice are not born in expected Mendelian ratios secondary to loss after E9.5. Embryonic stem cells from mutant mice show upregulated transcription of an adjacent gene, Dusp9. Thus, at an early and critical stage of development, dysregulated gene transcription is one consequence of the insertion mutation. DNA methylation of the ETn 5′ LTR is not correlated with phenotypic outcome in mutant mice. Polypodia is an example of an intergenic mobile element insertion in mice causing dramatic morphogenetic defects and fetal death.
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Affiliation(s)
- Jessica A. Lehoczky
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Peedikayil E. Thomas
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
- Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Kevin M. Patrie
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Kailey M. Owens
- Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lisa M. Villarreal
- Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Kenneth Galbraith
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Joe Washburn
- Biomedical Research Core Facilities, DNA Sequencing Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Craig N. Johnson
- Biomedical Research Core Facilities, DNA Sequencing Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Bryant Gavino
- Murine Molecular Constructs Laboratory-MMCL Mouse Biology Program, University of California, Davis, California, United States of America
| | - Alexander D. Borowsky
- University of California, Davis, Center for Comparative Medicine and Comprehensive Cancer Center, Department of Pathology and Laboratory Medicine, Davis, California, United States of America
| | - Kathleen J. Millen
- Division of Genetic Medicine, Department of Pediatrics, Seattle Children's Hospital, Seattle, Washington, United States of America
| | - Paul Wakenight
- Division of Genetic Medicine, Department of Pediatrics, Seattle Children's Hospital, Seattle, Washington, United States of America
| | - William Law
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Margaret L. Van Keuren
- Transgenic Animal Model Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Galina Gavrilina
- Transgenic Animal Model Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Elizabeth D. Hughes
- Transgenic Animal Model Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Thomas L. Saunders
- Transgenic Animal Model Core Lab, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lesil Brihn
- Department of Genetics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Joseph H. Nadeau
- Pacific Northwest Research Institute, Seattle, Washington, United States of America
| | - Jeffrey W. Innis
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
- Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Ferguson CJ, Lenk GM, Jones JM, Grant AE, Winters JJ, Dowling JJ, Giger RJ, Meisler MH. Neuronal expression of Fig4 is both necessary and sufficient to prevent spongiform neurodegeneration. Hum Mol Genet 2012; 21:3525-34. [PMID: 22581779 DOI: 10.1093/hmg/dds179] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
FIG4 is a ubiquitously expressed phosphatase that, in complex with FAB1/PIKFYVE and VAC14, regulates the biosynthesis of the signaling lipid PI(3,5)P(2). Null mutation of Fig4 in the mouse results in spongiform degeneration of brain and peripheral ganglia, defective myelination and juvenile lethality. Partial loss-of-function of human FIG4 results in a severe form of Charcot-Marie-Tooth neuropathy. Neurons from null mice contain enlarged vacuoles derived from the endosome/lysosome pathway, and astrocytes accumulate proteins involved in autophagy. Other cellular defects include astrogliosis and microgliosis. To distinguish the contributions of neurons and glia to spongiform degeneration in the Fig4 null mouse, we expressed Fig4 under the control of the neuron-specific enolase promoter and the astrocyte-specific glial fibrillary acidic protein promoter in transgenic mice. Neuronal expression of Fig4 was sufficient to rescue cellular and neurological phenotypes including spongiform degeneration, gliosis and juvenile lethality. In contrast, expression of Fig4 in astrocytes prevented accumulation of autophagy markers and microgliosis but did not prevent spongiform degeneration or lethality. To confirm the neuronal origin of spongiform degeneration, we generated a floxed allele of Fig4 and crossed it with mice expressing the Cre recombinase from the neuron-specific synapsin promoter. Mice with conditional inactivation of Fig4 in neurons developed spongiform degeneration and the full spectrum of neurological abnormalities. The data demonstrate that expression of Fig4 in neurons is necessary and sufficient to prevent spongiform degeneration. Therapy for patients with FIG4 deficiency will therefore require correction of the deficiency in neurons.
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Affiliation(s)
- C J Ferguson
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-6518, USA
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