scholarly journals PolyQ-independent toxicity associated with novel translational products from CAG repeat expansions

2019 ◽  
Author(s):  
Paige D. Rudich ◽  
Simon Watkins ◽  
Todd Lamitina
Keyword(s):  
Cell Types ◽  
Cag Repeat ◽  
Cag Repeats ◽  
C Elegans ◽  
Polyq Protein ◽  
Repeat Expansions ◽  
Multiple Cell ◽  
Nucleotide Repeats ◽  
Ran Translation

AbstractExpanded CAG nucleotide repeats are the underlying genetic cause of at least 14 incurable diseases, including Huntington’s disease (HD). The toxicity associated with many CAG repeat expansions is thought to be due to the translation of the CAG repeat to create a polyQ protein, which forms toxic oligomers and aggregates. However, recent studies show that HD CAG repeats undergo a non-canonical form of translation called Repeat-associated non-AUG dependent (RAN) translation. RAN translation of the CAG sense and CUG anti-sense RNAs produces six distinct repeat peptides: polyalanine (polyAla, from both CAG and CUG repeats), polyserine (polySer), polyleucine (polyLeu), polycysteine (polyCys), and polyglutamine (polyGln). The toxic potential of individual CAG-derived RAN polypeptides is not well understood. We developed pure C. elegans protein models for each CAG RAN polypeptide using codon-varied expression constructs that preserve RAN protein sequence but eliminate repetitive CAG/CUG RNA. While all RAN polypeptides formed aggregates, only polyLeu was consistently toxic across multiple cell types. In GABAergic neurons, which exhibit significant neurodegeneration in HD patients, codon-varied (Leu)38, but not (Gln)38, caused substantial neurodegeneration and motility defects. Our studies provide the first in vivo evaluation of CAG-derived RAN polypeptides and suggest that polyQ-independent mechanisms, such as RAN-translated polyLeu peptides, may have a significant pathological role in CAG repeat expansion disorders.

scholarly journals Lack of RAN-mediated toxicity in Huntington’s disease knock-in mice

2020 ◽  
Vol 117 (8) ◽  
pp. 4411-4417 ◽  
Author(s):  
Su Yang ◽  
Huiming Yang ◽  
Luoxiu Huang ◽  
Luxiao Chen ◽  
Zhaohui Qin ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Genome Editing ◽  
Mouse Models ◽  
Cag Repeat ◽  
Cag Repeats ◽  
Behavioral Phenotypes ◽  
Endogenous Level ◽  
Ran Translation

Identification of repeat-associated non-AUG (RAN) translation in trinucleotide (CAG) repeat diseases has led to the emerging concept that CAG repeat diseases are caused by nonpolyglutamine products. Nonetheless, the in vivo contribution of RAN translation to the pathogenesis of CAG repeat diseases remains elusive. Via CRISPR/Cas9-mediated genome editing, we established knock-in mouse models that harbor expanded CAG repeats in the mouse huntingtin gene to express RAN-translated products with or without polyglutamine peptides. We found that RAN translation is not detected in the knock-in mouse models when expanded CAG repeats are expressed at the endogenous level. Consistently, the expanded CAG repeats that cannot be translated into polyglutamine repeats do not yield the neuropathological and behavioral phenotypes that were found in knock-in mice expressing expanded polyglutamine repeats. Our findings suggest that RAN-translated products do not play a major role in the pathogenesis of CAG repeat diseases and underscore the importance in targeting polyglutamine repeats for therapeutics.

scholarly journals MyD88 Is Not Required for Muscle Injury-Induced Endochondral Heterotopic Ossification in a Mouse Model of Fibrodysplasia Ossificans Progressiva

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 630
Author(s):  
Huili Lyu ◽  
Cody M. Elkins ◽  
Jessica L. Pierce ◽  
C. Henrique Serezani ◽  
Daniel S. Perrien
Keyword(s):  
Heterotopic Ossification ◽  
Muscle Injury ◽  
Cell Types ◽  
Fibrodysplasia Ossificans Progressiva ◽  
Inflammatory Signaling ◽  
Conditional Deletion ◽  
Pathway Crosstalk ◽  
Multiple Cell

Excess inflammation and canonical BMP receptor (BMPR) signaling are coinciding hallmarks of the early stages of injury-induced endochondral heterotopic ossification (EHO), especially in the rare genetic disease fibrodysplasia ossificans progressiva (FOP). Multiple inflammatory signaling pathways can synergistically enhance BMP-induced Smad1/5/8 activity in multiple cell types, suggesting the importance of pathway crosstalk in EHO and FOP. Toll-like receptors (TLRs) and IL-1 receptors mediate many of the earliest injury-induced inflammatory signals largely via MyD88-dependent pathways. Thus, the hypothesis that MyD88-dependent signaling is required for EHO was tested in vitro and in vivo using global or Pdgfrα-conditional deletion of MyD88 in FOP mice. As expected, IL-1β or LPS synergistically increased Activin A (ActA)-induced phosphorylation of Smad 1/5 in fibroadipoprogenitors (FAPs) expressing Alk2R206H. However, conditional deletion of MyD88 in Pdgfrα-positive cells of FOP mice did not significantly alter the amount of muscle injury-induced EHO. Even more surprisingly, injury-induced EHO was not significantly affected by global deletion of MyD88. These studies demonstrate that MyD88-dependent signaling is dispensable for injury-induced EHO in FOP mice.

scholarly journals Single-cell mapping of focused ultrasound-transfected brain

Gene Therapy ◽  
2021 ◽  
Author(s):  
A. S. Mathew ◽  
C. M. Gorick ◽  
R. J. Price
Keyword(s):  
Single Cell ◽  
Focused Ultrasound ◽  
Cell Types ◽  
Brain Cell ◽  
Therapeutic Modality ◽  
Full Potential ◽  
Stress Genes ◽  
Multiple Cell ◽  
Differential Gene

AbstractGene delivery via focused ultrasound (FUS) mediated blood-brain barrier (BBB) opening is a disruptive therapeutic modality. Unlocking its full potential will require an understanding of how FUS parameters (e.g., peak-negative pressure (PNP)) affect transfected cell populations. Following plasmid (mRuby) delivery across the BBB with 1 MHz FUS, we used single-cell RNA-sequencing to ascertain that distributions of transfected cell types were highly dependent on PNP. Cells of the BBB (i.e., endothelial cells, pericytes, and astrocytes) were enriched at 0.2 MPa PNP, while transfection of cells distal to the BBB (i.e., neurons, oligodendrocytes, and microglia) was augmented at 0.4 MPa PNP. PNP-dependent differential gene expression was observed for multiple cell types. Cell stress genes were upregulated proportional to PNP, independent of cell type. Our results underscore how FUS may be tuned to bias transfection toward specific brain cell types in vivo and predict how those cells will respond to transfection.

scholarly journals Regulation of Fertility, Survival, and Cuticle Collagen Function by the Caenorhabditis elegans eaf-1 and ell-1 Genes

2011 ◽  
Vol 286 (41) ◽  
pp. 35915-35921 ◽  
Author(s):  
Liquan Cai ◽  
Binh L. Phong ◽  
Alfred L. Fisher ◽  
Zhou Wang
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Types ◽  
Transcriptional Elongation ◽  
Human Prostate Cancer ◽  
Prostate Cancer Cells ◽  
Transcription Factor Family ◽  
Collagen Expression ◽  
Extracellular Matrix Components ◽  
Multiple Cell

EAF2, an androgen-regulated protein, interacts with members of the ELL (eleven-nineteen lysine-rich leukemia) transcription factor family and also acts as a tumor suppressor. Although these proteins control transcriptional elongation and perhaps modulate the effects of other transcription factors, the mechanisms of their actions remain largely unknown. To gain new insights into the biology of the EAF2 and ELL family proteins, we used Caenorhabditis elegans as a model to explore the in vivo roles of their worm orthologs. Through the use of transgenic worms, RNAi, and an eaf-1 mutant, we found that both genes are expressed in multiple cell types throughout the worm life cycle and that they play important roles in fertility, survival, and body size regulation. ELL-1 and EAF-1 likely contribute to these activities in part through modulating cuticle synthesis, given that we observed a disrupted cuticle structure in ell-1 RNAi-treated or eaf-1 mutant worms. Consistent with disruption of cuticle structure, loss of either ELL-1 or EAF-1 suppressed the rol phenotype of specific collagen mutants, possibly through the control of dpy-3, dpy-13, and sqt-3 collagen gene expression. Furthermore, we also noted the regulation of collagen expression by ELL overexpression in PC3 human prostate cancer cells. Together, these results reveal important roles for the eaf-1 and ell-1 genes in the regulation of extracellular matrix components.

The expression, lamin-dependent localization and RNAi depletion phenotype for emerin inC. elegans

2002 ◽  
Vol 115 (5) ◽  
pp. 923-929 ◽  
Author(s):  
Yosef Gruenbaum ◽  
Kenneth K. Lee ◽  
Jun Liu ◽  
Merav Cohen ◽  
Katherine L. Wilson
Keyword(s):  
Nuclear Envelope ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Growth Conditions ◽  
Rnai Phenotype ◽  
Lamin B ◽  
C Elegans ◽  
Nuclear Lamins ◽  
First Time

Emerin belongs to the LEM-domain family of nuclear membrane proteins, which are conserved in metazoans from C. elegans to humans. Loss of emerin in humans causes the X-linked form of Emery-Dreifuss muscular dystrophy(EDMD), but the disease mechanism is not understood. We have begun to address the function of emerin in C. elegans, a genetically tractable nematode. The emerin gene (emr-1) is conserved in C. elegans. We detect Ce-emerin protein in the nuclear envelopes of all cell types except sperm, and find that Ce-emerin co-immunoprecipitates with Ce-lamin from embryo lysates. We show for the first time in any organism that nuclear lamins are essential for the nuclear envelope localization of emerin during early development. We further show that four other types of nuclear envelope proteins, including fellow LEM-domain protein Ce-MAN1, as well as Ce-lamin, UNC-84 and nucleoporins do not depend on Ce-emerin for their localization. This result suggests that emerin is not essential to organize or localize the only lamin (B-type) expressed in C. elegans. We also analyzed the RNAi phenotype resulting from the loss of emerin function in C. elegans under laboratory growth conditions, and found no detectable phenotype throughout development. We propose that C. elegans is an appropriate system in which to study the molecular mechanisms of emerin function in vivo.

Wnt5a Promotes Lysosomal Cholesterol Egress and Protects Against Atherosclerosis

2021 ◽  
Author(s):  
Sara Awan ◽  
Magalie Lambert ◽  
Ali Imtiaz ◽  
Fabien Alpy ◽  
Catherine Tomasetto ◽  
...  
Keyword(s):  
Dietary Cholesterol ◽  
Cell Types ◽  
Cholesterol Content ◽  
Cholesterol Homeostasis ◽  
Cholesterol Trafficking ◽  
Atherosclerotic Lesions ◽  
Crucial Component ◽  
Multiple Cell ◽  
Niemann Pick

Background: Impairment of cellular cholesterol trafficking is at the heart of atherosclerotic lesions formation. This involves egress of cholesterol from the lysosomes and two lysosomal proteins, the Niemann-Pick C1 (NPC1) and NPC2 that promotes cholesterol trafficking. However, movement of cholesterol out the lysosome and how disrupted cholesterol trafficking leads to atherosclerosis is unclear. As the Wnt ligand, Wnt5a inhibits the intracellular accumulation of cholesterol in multiple cell types, we tested whether Wnt5a interacts with the lysosomal cholesterol export machinery and studied its role in atherosclerotic lesions formation. Methods: We generated mice deleted for the Wnt5a gene in vascular smooth muscle cells (VSMCs). To establish whether Wnt5a also protects against cholesterol accumulation in human VSMCs, we used a CRISPR/Cas9 guided nuclease approach to generate human VSMCs knockout for Wnt5a. Results: We show that Wnt5a is a crucial component of the lysosomal cholesterol export machinery. By increasing lysosomal acid lipase expression, decreasing metabolic signaling by the mTORC1 kinase, and through binding to NPC1 and NPC2, Wnt5a senses changes in dietary cholesterol supply and promotes lysosomal cholesterol egress to the endoplasmic reticulum (ER). Consequently, loss of Wnt5a decoupled mTORC1 from variations in lysosomal sterol levels, disrupted lysosomal function, decreased cholesterol content in the ER, and promoted atherosclerosis. Conclusions: These results reveal an unexpected function of the Wnt5a pathway as essential for maintaining cholesterol homeostasis in vivo.

scholarly journals Regulation of Actin Dynamics in the C. elegans Somatic Gonad

2019 ◽  
Vol 7 (1) ◽  
pp. 6 ◽  
Author(s):  
Charlotte Kelley ◽  
Erin Cram
Keyword(s):  
Reproductive System ◽  
Cell Types ◽  
Actin Dynamics ◽  
Entry And Exit ◽  
Cell Type ◽  
C Elegans ◽  
Type Study ◽  
Somatic Gonad ◽  
Uterus Contraction

The reproductive system of the hermaphroditic nematode C. elegans consists of a series of contractile cell types—including the gonadal sheath cells, the spermathecal cells and the spermatheca–uterine valve—that contract in a coordinated manner to regulate oocyte entry and exit of the fertilized embryo into the uterus. Contraction is driven by acto-myosin contraction and relies on the development and maintenance of specialized acto-myosin networks in each cell type. Study of this system has revealed insights into the regulation of acto-myosin network assembly and contractility in vivo.

scholarly journals Mesenchymal Stem Cells as a Promising Cell Source for Integration in Novel In Vitro Models

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1306
Author(s):  
Ann-Kristin Afflerbach ◽  
Mark D. Kiri ◽  
Tahir Detinis ◽  
Ben M. Maoz
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Cell Types ◽  
In Vitro Models ◽  
Cell Source ◽  
Fundamental Research ◽  
Multiple Cell ◽  
Vitro Model

The human-relevance of an in vitro model is dependent on two main factors—(i) an appropriate human cell source and (ii) a modeling platform that recapitulates human in vivo conditions. Recent years have brought substantial advancements in both these aspects. In particular, mesenchymal stem cells (MSCs) have emerged as a promising cell source, as these cells can differentiate into multiple cell types, yet do not raise the ethical and practical concerns associated with other types of stem cells. In turn, advanced bioengineered in vitro models such as microfluidics, Organs-on-a-Chip, scaffolds, bioprinting and organoids are bringing researchers ever closer to mimicking complex in vivo environments, thereby overcoming some of the limitations of traditional 2D cell cultures. This review covers each of these advancements separately and discusses how the integration of MSCs into novel in vitro platforms may contribute enormously to clinical and fundamental research.

scholarly journals Sertoli cell ablation and replacement of the spermatogonial niche in mouse

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Tetsuhiro Yokonishi ◽  
Jennifer McKey ◽  
Shintaro Ide ◽  
Blanche Capel
Keyword(s):  
Sertoli Cells ◽  
Cell Types ◽  
Supporting Cell ◽  
Idiopathic Male Infertility ◽  
Testicular Cells ◽  
Cell Ablation ◽  
Toxic Drug ◽  
Donor Cells ◽  
Multiple Cell

AbstractSpermatogonia, which produce sperm throughout the male lifetime, are regulated inside a niche composed of Sertoli cells, and other testis cell types. Defects in Sertoli cells often lead to infertility, but replacement of defective cells has been limited by the inability to deplete the existing population. Here, we use an FDA-approved non-toxic drug, benzalkonium chloride (BC), to deplete testis cell types in vivo. Four days after BC administration, Sertoli cells are preferentially depleted, and can be replaced to promote spermatogenesis from surviving (host) spermatogonia. Seven days after BC treatment, multiple cell types can be engrafted from fresh or cryopreserved testicular cells, leading to complete spermatogenesis from donor cells. These methods will be valuable for investigation of niche-supporting cell interactions, have the potential to lead to a therapy for idiopathic male infertility in the clinic, and could open the door to production of sperm from other species in the mouse.

scholarly journals Merging Microfluidics with Microtitre Technology for More Efficient Drug Discovery

2008 ◽  
Vol 13 (5) ◽  
pp. 275-279 ◽  
Author(s):  
Nicole V. Tolan ◽  
Luiza I. Genes ◽  
Dana M. Spence
Keyword(s):  
Cellular Response ◽  
Simultaneous Detection ◽  
Drug Efficacy ◽  
Cell Types ◽  
Microtitre Plate ◽  
Multiple Components ◽  
Multiple Cell ◽  
Improve Blood Flow

Detecting multiple components from a single red blood cell (RBC) sample within a flow-based system in less than 20 min will enable improved in vitro determinations of drug efficacy and cellular response to administered drugs. Here, an example of an improved in vitro measurement involving iloprost, a pharmaceutical reported to improve blood flow, has been determined by incorporating multiple cell types onto a single device. The method allows fluid flow to address individual rows of wells contained within an 18-well microfluidic array that serves as a precursor to a 96-well microtitre plate device. The ability to better mimic the in vivo circulation by incorporating the flow of blood components, coupled with simultaneous detection and laboratory automation in place for microtitre plates, suggests that the microfluidic array presented here will allow for improved mechanistic drug research studies. Using fluorescence microscopy, concentrations of multiple metabolites present within the RBC can also be determined using the microfluidic array. The current progress toward using this device for personalized medicine is presented here.

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