1
|
Huang Y, Dong X, Sun SY, Lim TK, Lin Q, He CY. ARL3 GTPases facilitate ODA16 unloading from IFT in motile cilia. SCIENCE ADVANCES 2024; 10:eadq2950. [PMID: 39231220 PMCID: PMC11373600 DOI: 10.1126/sciadv.adq2950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 07/30/2024] [Indexed: 09/06/2024]
Abstract
Eukaryotic cilia and flagella are essential for cell motility and sensory functions. Their biogenesis and maintenance rely on the intraflagellar transport (IFT). Several cargo adapters have been identified to aid IFT cargo transport, but how ciliary cargos are discharged from the IFT remains largely unknown. During our explorations of small GTPases ARL13 and ARL3 in Trypanosoma brucei, we found that ODA16, a known IFT cargo adapter present exclusively in motile cilia, is a specific effector of ARL3. In the cilia, active ARL3 GTPases bind to ODA16 and dissociate ODA16 from the IFT complex. Depletion of ARL3 GTPases stabilizes ODA16 interaction with the IFT, leading to ODA16 accumulation in cilia and defects in axonemal assembly. The interactions between human ODA16 homolog HsDAW1 and ARL GTPases are conserved, and these interactions are altered in HsDAW1 disease variants. These findings revealed a conserved function of ARL GTPases in IFT transport of motile ciliary components, and a mechanism of cargo unloading from the IFT.
Collapse
Affiliation(s)
- Yameng Huang
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Xiaoduo Dong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Stella Y Sun
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Teck-Kwang Lim
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Qingsong Lin
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Cynthia Y He
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- The Centre for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| |
Collapse
|
2
|
Placidi G, D'Agostino E, Maltese PE, Savastano MC, Gambini G, Rizzo S, Bonetti G, Bertelli M, Chiurazzi P, Falsini B. A novel homozygous splice site variant in ARL2BP causes a syndromic autosomal recessive rod-cone dystrophy with situs inversus, asthenozoospermia, unilateral renal agenesis and microcysts. BMC Med Genomics 2024; 17:100. [PMID: 38649918 PMCID: PMC11036775 DOI: 10.1186/s12920-024-01868-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 04/08/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND This report presents a clinical case of syndromic rod-cone dystrophy due to a splice site variant in the ARL2BP gene causing situs inversus, asthenozoospermia, unilateral renal agenesis and microcysts. The presence of renal agenesis and cryptorchidism expands the clinical manifestations due to ARL2BP variants. The detailed, long-term follow-up contributes valuable insights into disease progression, aiding clinical diagnosis and patient management. CASE PRESENTATION The male patient complained of photophobia as the first symptom when he was 20 years old followed by nyctalopia, loss of central visual acuity and peripheral visual field ten years later. Genetic analysis identified a likely pathogenic homozygous variant (c.294-1G > C) involving the splicing acceptor site of intron 4. Reported symptoms together with full-field stimulus threshold testing, electroretinogram and advanced multimodal imaging allowed us to recognize the typical characteristics of a mixed retinal dystrophy. Despite the end-stage retinal disease, this patient still retained a useful residual vision at 63 years and had a slow disease progression during the last 5 years of evaluation. DISCUSSION AND CONCLUSIONS Our findings underscore the variable clinical presentation of ARL2BP variants, emphasizing the importance of a nuanced approach in diagnosing and managing patients. The presence of renal cysts warrants consideration of a differential diagnosis, particularly with Senior-Loken (SLS), Bardet-Biedl (BBS) and Joubert syndromes (JS) but also with Short Rib Thoracic Dysplasia 9, highlighting the need for careful phenotypic evaluation in these cases.
Collapse
Affiliation(s)
- Giorgio Placidi
- UOC Oculistica, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Largo Gemelli 8, 00168, Rome, Italy
| | - Elena D'Agostino
- UOC Oculistica, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Largo Gemelli 8, 00168, Rome, Italy
| | | | - Maria Cristina Savastano
- UOC Oculistica, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Largo Gemelli 8, 00168, Rome, Italy
- Istituto di Oftalmologia, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168, Rome, Italy
| | - Gloria Gambini
- UOC Oculistica, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Largo Gemelli 8, 00168, Rome, Italy
- Istituto di Oftalmologia, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168, Rome, Italy
| | - Stanislao Rizzo
- UOC Oculistica, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Largo Gemelli 8, 00168, Rome, Italy
- Istituto di Oftalmologia, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168, Rome, Italy
- Istituto di Neuroscienze, Consiglio Nazionale Delle Ricerche, Pisa, Italy
| | - Gabriele Bonetti
- MAGI'S LAB, 38068, Rovereto, Italy
- MAGI EUREGIO, 39100, Bolzano, Italy
| | - Matteo Bertelli
- MAGI'S LAB, 38068, Rovereto, Italy
- MAGI EUREGIO, 39100, Bolzano, Italy
- MAGISNAT, Atlanta Tech Park, 107 Technology Parkway, 30092, Peachtree Corners, GA, USA
| | - Pietro Chiurazzi
- Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168, Rome, Italy
- UOC Genetica Medica, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Largo Gemelli 8, 00168, Rome, Italy
| | - Benedetto Falsini
- UOC Oculistica, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Largo Gemelli 8, 00168, Rome, Italy
- Istituto di Oftalmologia, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168, Rome, Italy
| |
Collapse
|
3
|
Aljammal R, Saravanan T, Guan T, Rhodes S, Robichaux MA, Ramamurthy V. Excessive tubulin glutamylation leads to progressive cone-rod dystrophy and loss of outer segment integrity. Hum Mol Genet 2024; 33:802-817. [PMID: 38297980 DOI: 10.1093/hmg/ddae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/29/2023] [Accepted: 01/09/2024] [Indexed: 02/02/2024] Open
Abstract
Mutations in Cytosolic Carboxypeptidase-like Protein 5 (CCP5) are associated with vision loss in humans. To decipher the mechanisms behind CCP5-associated blindness, we generated a novel mouse model lacking CCP5. In this model, we found that increased tubulin glutamylation led to progressive cone-rod dystrophy, with cones showing a more pronounced and earlier functional loss than rod photoreceptors. The observed functional reduction was not due to cell death, levels, or the mislocalization of major phototransduction proteins. Instead, the increased tubulin glutamylation caused shortened photoreceptor axonemes and the formation of numerous abnormal membranous whorls that disrupted the integrity of photoreceptor outer segments (OS). Ultimately, excessive tubulin glutamylation led to the progressive loss of photoreceptors, affecting cones more severely than rods. Our results highlight the importance of maintaining tubulin glutamylation for normal photoreceptor function. Furthermore, we demonstrate that murine cone photoreceptors are more sensitive to disrupted tubulin glutamylation levels than rods, suggesting an essential role for axoneme in the structural integrity of the cone outer segment. This study provides valuable insights into the mechanisms of photoreceptor diseases linked to excessive tubulin glutamylation.
Collapse
Affiliation(s)
- Rawaa Aljammal
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, 64 Medical Center Dr., Morgantown, WV 26506, United States
- Department of Ophthalmology and Visual Sciences, One Stadium Dr, West Virginia University, Morgantown, WV 26506, United States
| | - Thamaraiselvi Saravanan
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, 64 Medical Center Dr., Morgantown, WV 26506, United States
- Department of Ophthalmology and Visual Sciences, One Stadium Dr, West Virginia University, Morgantown, WV 26506, United States
| | - Tongju Guan
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, 64 Medical Center Dr., Morgantown, WV 26506, United States
- Department of Ophthalmology and Visual Sciences, One Stadium Dr, West Virginia University, Morgantown, WV 26506, United States
| | - Scott Rhodes
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, 64 Medical Center Dr., Morgantown, WV 26506, United States
- Department of Ophthalmology and Visual Sciences, One Stadium Dr, West Virginia University, Morgantown, WV 26506, United States
| | - Michael A Robichaux
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, 64 Medical Center Dr., Morgantown, WV 26506, United States
- Department of Ophthalmology and Visual Sciences, One Stadium Dr, West Virginia University, Morgantown, WV 26506, United States
| | - Visvanathan Ramamurthy
- Department of Biochemistry and Molecular Medicine, School of Medicine, West Virginia University, 64 Medical Center Dr., Morgantown, WV 26506, United States
- Department of Ophthalmology and Visual Sciences, One Stadium Dr, West Virginia University, Morgantown, WV 26506, United States
| |
Collapse
|
4
|
Munezero D, Aliff H, Salido E, Saravanan T, Sanzhaeva U, Guan T, Ramamurthy V. HSP90α is needed for the survival of rod photoreceptors and regulates the expression of rod PDE6 subunits. J Biol Chem 2023; 299:104809. [PMID: 37172722 PMCID: PMC10250166 DOI: 10.1016/j.jbc.2023.104809] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023] Open
Abstract
Heat shock protein 90 (HSP90) is an abundant molecular chaperone that regulates the stability of a small set of proteins essential in various cellular pathways. Cytosolic HSP90 has two closely related paralogs: HSP90α and HSP90β. Due to the structural and sequence similarities of cytosolic HSP90 paralogs, identifying the unique functions and substrates in the cell remains challenging. In this article, we assessed the role of HSP90α in the retina using a novel HSP90α murine knockout model. Our findings show that HSP90α is essential for rod photoreceptor function but was dispensable in cone photoreceptors. In the absence of HSP90α, photoreceptors developed normally. We observed rod dysfunction in HSP90α knockout at 2 months with the accumulation of vacuolar structures, apoptotic nuclei, and abnormalities in the outer segments. The decline in rod function was accompanied by progressive degeneration of rod photoreceptors that was complete at 6 months. The deterioration in cone function and health was a "bystander effect" that followed the degeneration of rods. Tandem mass tag proteomics showed that HSP90α regulates the expression levels of <1% of the retinal proteome. More importantly, HSP90α was vital in maintaining rod PDE6 and AIPL1 cochaperone levels in rod photoreceptor cells. Interestingly, cone PDE6 levels were unaffected. The robust expression of HSP90β paralog in cones likely compensates for the loss of HSP90α. Overall, our study demonstrated the critical need for HSP90α chaperone in the maintenance of rod photoreceptors and showed potential substrates regulated by HSP90α in the retina.
Collapse
Affiliation(s)
- Daniella Munezero
- Department of Pharmaceutical and Pharmacological Sciences, West Virginia University, Morgantown, West Virginia, USA; Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Hunter Aliff
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Ezequiel Salido
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Thamaraiselvi Saravanan
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Urikhan Sanzhaeva
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Tongju Guan
- Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA
| | - Visvanathan Ramamurthy
- Department of Pharmaceutical and Pharmacological Sciences, West Virginia University, Morgantown, West Virginia, USA; Ophthalmology and Visual Sciences, West Virginia University, Morgantown, West Virginia, USA; Biochemistry and Molecular Medicine, West Virginia University, Morgantown, West Virginia, USA.
| |
Collapse
|
5
|
Zhu T, Li H, Wei X, Li W, Sun Z, Sui R. Novel homozygous variant in ARL2BP associated with retinitis pigmentosa, situs inversus, and male infertility in a Chinese patient. Clin Genet 2023; 103:472-477. [PMID: 36507858 DOI: 10.1111/cge.14278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 12/05/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022]
Abstract
ARL2BP is a ciliary gene associated with multiple ciliopathy phenotypes. On comprehensive clinical examinations using molecular methods, we identified a Chinese patient from a consanguineous family carrying a novel homozygous variant c.22_23delAG (p.S8Lfs*10) in ARL2BP, presenting with retinitis pigmentosa (RP), situs inversus totalis, and oligozoospermia. Situs inversus and male infertility have never been reported in the same patient with ARL2BP variants; therefore, this a novel ARL2BP-associated phenotypic triad of RP, situs inversus, and male infertility. Moreover, this patient likely had olfactory dysfunction susceptibility and presented with anosmia. We found reduced patient-derived fibroblast proliferation and ciliary length. Our findings expand the genotypic spectrum and reveal abnormal cell proliferation and ciliogenesis in ARL2BP-associated patients.
Collapse
Affiliation(s)
- Tian Zhu
- Department of Ophthalmology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui Li
- Department of Ophthalmology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xing Wei
- Department of Ophthalmology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wuyi Li
- Department of Ophthalmology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zixi Sun
- Department of Ophthalmology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ruifang Sui
- Department of Ophthalmology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| |
Collapse
|
6
|
Gerstner CD, Reed M, Dahl TM, Ying G, Frederick JM, Baehr W. Arf-like Protein 2 (ARL2) Controls Microtubule Neogenesis during Early Postnatal Photoreceptor Development. Cells 2022; 12:147. [PMID: 36611941 PMCID: PMC9818799 DOI: 10.3390/cells12010147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/12/2022] [Accepted: 12/21/2022] [Indexed: 12/31/2022] Open
Abstract
Arf-like protein 2 (ARL2) is a ubiquitously expressed small GTPase with multiple functions. In a cell culture, ARL2 participates with tubulin cofactor D (TBCD) in the neogenesis of tubulin αβ-heterodimers, the building blocks of microtubules. To evaluate this function in the retina, we conditionally deleted ARL2 in mouse retina at two distinct stages, either during the embryonic development (retArl2-/-) or after ciliogenesis specifically in rods (rodArl2-/-). retArl2-/- retina sections displayed distorted nuclear layers and a disrupted microtubule cytoskeleton (MTC) as early as postnatal day 6 (P6). Rod and cone outer segments (OS) did not form. By contrast, the rod ARL2 knockouts were stable at postnatal day 35 and revealed normal ERG responses. Cytoplasmic dynein is reduced in retArl2-/- inner segments (IS), suggesting that dynein may be unstable in the absence of a normal MTC. We investigated the microtubular stability in the absence of either ARL2 (retARL2-/-) or DYNC1H1 (retDync1h1-/-), the dynein heavy chain, and found that both the retArl2-/- and retDync1h1-/- retinas exhibited reduced microtubules and nuclear layer distortion. The results suggest that ARL2 and dynein depend on each other to generate a functional MTC during the early photoreceptor development.
Collapse
Affiliation(s)
- Cecilia D. Gerstner
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, UT 84132, USA
| | - Michelle Reed
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, UT 84132, USA
| | - Tiffanie M. Dahl
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, UT 84132, USA
| | - Guoxin Ying
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, UT 84132, USA
| | - Jeanne M. Frederick
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, UT 84132, USA
| | - Wolfgang Baehr
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, UT 84132, USA
- Department of Neurobiology & Anatomy, University of Utah, Salt Lake City, UT 84112, USA
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| |
Collapse
|
7
|
A comprehensive WGS-based pipeline for the identification of new candidate genes in inherited retinal dystrophies. NPJ Genom Med 2022; 7:17. [PMID: 35246562 PMCID: PMC8897414 DOI: 10.1038/s41525-022-00286-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 02/04/2022] [Indexed: 12/11/2022] Open
Abstract
To enhance the use of Whole Genome Sequencing (WGS) in clinical practice, it is still necessary to standardize data analysis pipelines. Herein, we aimed to define a WGS-based algorithm for the accurate interpretation of variants in inherited retinal dystrophies (IRD). This study comprised 429 phenotyped individuals divided into three cohorts. A comparison of 14 pathogenicity predictors, and the re-definition of its cutoffs, were performed using panel-sequencing curated data from 209 genetically diagnosed individuals with IRD (training cohort). The optimal tool combinations, previously validated in 50 additional IRD individuals, were also tested in patients with hereditary cancer (n = 109), and with neurological diseases (n = 47) to evaluate the translational value of this approach (validation cohort). Then, our workflow was applied for the WGS-data analysis of 14 individuals from genetically undiagnosed IRD families (discovery cohort). The statistical analysis showed that the optimal filtering combination included CADDv1.6, MAPP, Grantham, and SIFT tools. Our pipeline allowed the identification of one homozygous variant in the candidate gene CFAP20 (c.337 C > T; p.Arg113Trp), a conserved ciliary gene, which was abundantly expressed in human retina and was located in the photoreceptors layer. Although further studies are needed, we propose CFAP20 as a candidate gene for autosomal recessive retinitis pigmentosa. Moreover, we offer a translational strategy for accurate WGS-data prioritization, which is essential for the advancement of personalized medicine.
Collapse
|
8
|
Wensel TG, Potter VL, Moye A, Zhang Z, Robichaux MA. Structure and dynamics of photoreceptor sensory cilia. Pflugers Arch 2021; 473:1517-1537. [PMID: 34050409 PMCID: PMC11216635 DOI: 10.1007/s00424-021-02564-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 02/06/2023]
Abstract
The rod and cone photoreceptor cells of the vertebrate retina have highly specialized structures that enable them to carry out their function of light detection over a broad range of illumination intensities with optimized spatial and temporal resolution. Most prominent are their unusually large sensory cilia, consisting of outer segments packed with photosensitive disc membranes, a connecting cilium with many features reminiscent of the primary cilium transition zone, and a pair of centrioles forming a basal body which serves as the platform upon which the ciliary axoneme is assembled. These structures form a highway through which an enormous flux of material moves on a daily basis to sustain the continual turnover of outer segment discs and the energetic demands of phototransduction. After decades of study, the details of the fine structure and distribution of molecular components of these structures are still incompletely understood, but recent advances in cellular imaging techniques and animal models of inherited ciliary defects are yielding important new insights. This knowledge informs our understanding both of the mechanisms of trafficking and assembly and of the pathophysiological mechanisms of human blinding ciliopathies.
Collapse
Affiliation(s)
- Theodore G Wensel
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology and Developmental Biology Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Valencia L Potter
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology and Developmental Biology Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA
- Medical Scientist Training Program (MSTP), Baylor College of Medicine, Houston, TX, 77030, USA
| | - Abigail Moye
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Zhixian Zhang
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Michael A Robichaux
- Departments of Ophthalmology and Biochemistry, West Virginia University, Morgantown, WV, USA
| |
Collapse
|
9
|
Barnes CL, Malhotra H, Calvert PD. Compartmentalization of Photoreceptor Sensory Cilia. Front Cell Dev Biol 2021; 9:636737. [PMID: 33614665 PMCID: PMC7889997 DOI: 10.3389/fcell.2021.636737] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/07/2021] [Indexed: 12/12/2022] Open
Abstract
Functional compartmentalization of cells is a universal strategy for segregating processes that require specific components, undergo regulation by modulating concentrations of those components, or that would be detrimental to other processes. Primary cilia are hair-like organelles that project from the apical plasma membranes of epithelial cells where they serve as exclusive compartments for sensing physical and chemical signals in the environment. As such, molecules involved in signal transduction are enriched within cilia and regulating their ciliary concentrations allows adaptation to the environmental stimuli. The highly efficient organization of primary cilia has been co-opted by major sensory neurons, olfactory cells and the photoreceptor neurons that underlie vision. The mechanisms underlying compartmentalization of cilia are an area of intense current research. Recent findings have revealed similarities and differences in molecular mechanisms of ciliary protein enrichment and its regulation among primary cilia and sensory cilia. Here we discuss the physiological demands on photoreceptors that have driven their evolution into neurons that rely on a highly specialized cilium for signaling changes in light intensity. We explore what is known and what is not known about how that specialization appears to have driven unique mechanisms for photoreceptor protein and membrane compartmentalization.
Collapse
Affiliation(s)
| | | | - Peter D. Calvert
- Department of Ophthalmology and Visual Sciences, Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY, United States
| |
Collapse
|
10
|
Zhang X, Wang X, Xue Z, Zhan G, Ito Y, Guo Z. Prevention properties on cerebral ischemia reperfusion of medicine food homologous Dioscorea yam-derived diosgenin based on mediation of potential targets. Food Chem 2020; 345:128672. [PMID: 33352403 DOI: 10.1016/j.foodchem.2020.128672] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 10/27/2020] [Accepted: 11/15/2020] [Indexed: 10/23/2022]
Abstract
I/R (cerebral ischemia reperfusion injury) is the secondary complication of ischemic stroke patients that are immediately treated with drug thrombolysis or vascular recanalization in clinic. Diosgenin (DIO) purified from medicine food homologous (MFH) Dioscorea yam source is served as a fatal starting material to synthesize multifarious steroidal anti-inflammatory drugs in medicinal field, and has previously been demonstrated the potential prevention of I/R. However, the detailed mechanisms of neuroprotective effects against I/R remain elusively understood. Here, a global proteomic dynamics of rat right hemisphere brains was executed to investigate the protein expression patterns with a quantitative LC-MSn. In total, 5043 proteins were identified and 418 ones were determined to be significantly dysregulated DEPs (differentially expressed proteins) in comparison of Sham verse I/R and I/R verse DIO after onset stage of I/R, among which 5 DEPs namely BICD2, HNRNPK, CEP41, PPM1K, and ARL2BP, whose biological functions were mainly clustered into the mediation of nervous system, were selected for further validation in vitro and in vivo, and the change tendency expectedly supported the proteomic findings. Additionally, the AUC value of the combined ROC of these 5 DEPs was 0.988 with P < 0.0001, higher than every single one. Collectively, these scientific findings attributed to a typical investigation of dietary Dioscorea-enriched diosgenin in MFH research, suggesting that diosgenin or its derivatives were potential to be developed into food supplements or healthy food products to reveal healthy benefits in natural prevention and reduction risk of I/R. This work also promoted reasonable consumption of Dioscorea yams and contributed to the function of diosgenin-derived products and their applications in food industry.
Collapse
Affiliation(s)
- Xinxin Zhang
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China; Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai, China
| | - Xingbin Wang
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Zhaowei Xue
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Guanqun Zhan
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Yoichiro Ito
- Laboratory of Bio-separation Technologies, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Zengjun Guo
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China.
| |
Collapse
|
11
|
Lee L, Ostrowski LE. Motile cilia genetics and cell biology: big results from little mice. Cell Mol Life Sci 2020; 78:769-797. [PMID: 32915243 DOI: 10.1007/s00018-020-03633-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 08/11/2020] [Accepted: 09/03/2020] [Indexed: 12/13/2022]
Abstract
Our understanding of motile cilia and their role in disease has increased tremendously over the last two decades, with critical information and insight coming from the analysis of mouse models. Motile cilia form on specific epithelial cell types and typically beat in a coordinated, whip-like manner to facilitate the flow and clearance of fluids along the cell surface. Defects in formation and function of motile cilia result in primary ciliary dyskinesia (PCD), a genetically heterogeneous disorder with a well-characterized phenotype but no effective treatment. A number of model systems, ranging from unicellular eukaryotes to mammals, have provided information about the genetics, biochemistry, and structure of motile cilia. However, with remarkable resources available for genetic manipulation and developmental, pathological, and physiological analysis of phenotype, the mouse has risen to the forefront of understanding mammalian motile cilia and modeling PCD. This is evidenced by a large number of relevant mouse lines and an extensive body of genetic and phenotypic data. More recently, application of innovative cell biological techniques to these models has enabled substantial advancement in elucidating the molecular and cellular mechanisms underlying the biogenesis and function of mammalian motile cilia. In this article, we will review genetic and cell biological studies of motile cilia in mouse models and their contributions to our understanding of motile cilia and PCD pathogenesis.
Collapse
Affiliation(s)
- Lance Lee
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA. .,Department of Pediatrics, Sanford School of Medicine of the University of South Dakota, Sioux Falls, SD, USA.
| | - Lawrence E Ostrowski
- Marsico Lung Institute/Cystic Fibrosis Center and Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| |
Collapse
|
12
|
Application of CRISPR Tools for Variant Interpretation and Disease Modeling in Inherited Retinal Dystrophies. Genes (Basel) 2020; 11:genes11050473. [PMID: 32349249 PMCID: PMC7290804 DOI: 10.3390/genes11050473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 04/23/2020] [Accepted: 04/23/2020] [Indexed: 12/27/2022] Open
Abstract
Inherited retinal dystrophies are an assorted group of rare diseases that collectively account for the major cause of visual impairment of genetic origin worldwide. Besides clinically, these vision loss disorders present a high genetic and allelic heterogeneity. To date, over 250 genes have been associated to retinal dystrophies with reported causative variants of every nature (nonsense, missense, frameshift, splice-site, large rearrangements, and so forth). Except for a fistful of mutations, most of them are private and affect one or few families, making it a challenge to ratify the newly identified candidate genes or the pathogenicity of dubious variants in disease-associated loci. A recurrent option involves altering the gene in in vitro or in vivo systems to contrast the resulting phenotype and molecular imprint. To validate specific mutations, the process must rely on simulating the precise genetic change, which, until recently, proved to be a difficult endeavor. The rise of the CRISPR/Cas9 technology and its adaptation for genetic engineering now offers a resourceful suite of tools to alleviate the process of functional studies. Here we review the implementation of these RNA-programmable Cas9 nucleases in culture-based and animal models to elucidate the role of novel genes and variants in retinal dystrophies.
Collapse
|
13
|
Proteoglycan IMPG2 Shapes the Interphotoreceptor Matrix and Modulates Vision. J Neurosci 2020; 40:4059-4072. [PMID: 32265257 DOI: 10.1523/jneurosci.2994-19.2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/29/2020] [Accepted: 03/19/2020] [Indexed: 12/13/2022] Open
Abstract
Photoreceptor neurons are surrounded by an extracellular matrix, called the interphotoreceptor matrix (IPM). Activities crucial to vision occur within the IPM, including trafficking of nutrients and metabolites, retinal attachment, and interactions needed for normal outer segment phagocytosis. The IPM includes the following two unique proteoglycans: IPM proteoglycan 1 (IMPG1) and IMPG2. Patients with mutations in IMPG1/IMPG2 develop visual deficits with subretinal material accumulation, highlighting the critical role of the IPM in vision. To determine the role of these proteoglycans in retinal physiology and the pathologic mechanisms that lead to vision loss, we generated mouse models lacking IMPG1/IMPG2. In normal retina, IMPG1 and IMPG2 occupy distinct IPM compartments, represent the main source of chondroitin sulfate and are fundamental for the constitution of the cone-specific glycocalyx stained by the PNA (peanut agglutinin) lectin marker. No evident morphologic or functional deficits were found in mice lacking IMPG1. In the absence of IMPG2, IMPG1 abnormally accumulated at the subretinal space need, likely leading to the formation of subretinal lesions and reduced visual function. Interestingly, mice lacking both IMPG1 and IMPG2, regardless of sex, showed normal retinal structure and function, demonstrating that the aberrant IMPG1 distribution is the main cause of the visual alterations observed in the absence of IMPG2. In conclusion, our results show the dependence of secreted proteoglycans such as IMPG1 on the extracellular environment to properly integrate into the matrix, demonstrate the role of IMPG2 in shaping the IPM, and shed light on the potential mechanisms leading to the development of subretinal lesions and vision loss.SIGNIFICANCE STATEMENT The photoreceptors are specialized neurons that drive phototransduction in the mammalian retina. These cells are organized and surrounded by an extracellular matrix, the interphotoreceptor matrix (IPM). Mutations in IPM proteoglycans are associated with blindness in humans. Our studies show that two specific proteoglycans of the IPM, IPM proteoglycan 1 (IMPG1) and IMPG2, form a dynamic structure with distinct localization and dependency. When IMPG2 is absent, IMPG1 cannot integrate into the IPM, leading to abnormal proteoglycan accumulation and visual deficits. This work adds a new layer of understanding to IPM physiology and describes the pathologic events following deficits in proteoglycans, providing novel possibilities for visual restoration in patients with IMPG-related pathologies.
Collapse
|
14
|
Moye AR, Bedoni N, Cunningham JG, Sanzhaeva U, Tucker ES, Mathers P, Peter VG, Quinodoz M, Paris LP, Coutinho-Santos L, Camacho P, Purcell MG, Winkelmann AC, Foster JA, Pugacheva EN, Rivolta C, Ramamurthy V. Mutations in ARL2BP, a protein required for ciliary microtubule structure, cause syndromic male infertility in humans and mice. PLoS Genet 2019; 15:e1008315. [PMID: 31425546 PMCID: PMC6715254 DOI: 10.1371/journal.pgen.1008315] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 08/29/2019] [Accepted: 07/17/2019] [Indexed: 12/30/2022] Open
Abstract
Cilia are evolutionarily conserved hair-like structures with a wide spectrum of key biological roles, and their dysfunction has been linked to a growing class of genetic disorders, known collectively as ciliopathies. Many strides have been made towards deciphering the molecular causes for these diseases, which have in turn expanded the understanding of cilia and their functional roles. One recently-identified ciliary gene is ARL2BP, encoding the ADP-Ribosylation Factor Like 2 Binding Protein. In this study, we have identified multiple ciliopathy phenotypes associated with mutations in ARL2BP in human patients and in a mouse knockout model. Our research demonstrates that spermiogenesis is impaired, resulting in abnormally shaped heads, shortened and mis-assembled sperm tails, as well as in loss of axonemal doublets. Additional phenotypes in the mouse included enlarged ventricles of the brain and situs inversus. Mouse embryonic fibroblasts derived from knockout animals revealed delayed depolymerization of primary cilia. Our results suggest that ARL2BP is required for the structural maintenance of cilia as well as of the sperm flagellum, and that its deficiency leads to syndromic ciliopathy. The flagellated tails of sperm cells require a stringent developmental process that is essential for motility and fertility. The components that comprise the sperm tail assemble in regulated steps with protein processing, transport, and structural assembly dependent on each other for sperm tail maturity. In this work, we have identified ARL2BP, a previously retinal-associated protein, to be essential for sperm tail development and assembly. We show that without functional ARL2BP in humans or mice, sperm tails fail to develop, starting with the assembly of the core microtubular structure within the tail. Loss of ARL2BP also effects other ciliated cells, indicating a unique role for ARL2BP in ciliary microtubule formation. This research on ARL2BP provides further understanding on the links between vision and fertility. This work also demonstrates how genomic studies for human patients and murine models can coincide to provide greater insight into disease.
Collapse
Affiliation(s)
- Abigail R. Moye
- Department of Ophthalmology, West Virginia University, Morgantown, United States of America
- Department of Biochemistry, West Virginia University, Morgantown, United States of America
| | - Nicola Bedoni
- Department of Computational Biology, Unit of Medical Genetics, University of Lausanne, Lausanne, Switzerland
| | - Jessica G. Cunningham
- Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV, United States of America
| | - Urikhan Sanzhaeva
- Department of Biochemistry, West Virginia University, Morgantown, United States of America
| | - Eric S. Tucker
- Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV, United States of America
| | - Peter Mathers
- Department of Ophthalmology, West Virginia University, Morgantown, United States of America
- Department of Biochemistry, West Virginia University, Morgantown, United States of America
- Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV, United States of America
| | - Virginie G. Peter
- Department of Computational Biology, Unit of Medical Genetics, University of Lausanne, Lausanne, Switzerland
| | - Mathieu Quinodoz
- Department of Computational Biology, Unit of Medical Genetics, University of Lausanne, Lausanne, Switzerland
| | - Liliana P. Paris
- Department of Ophthalmology, Instituto de Oftalmologia Dr Gama Pinto, Lisbon, Portugal
| | - Luísa Coutinho-Santos
- Department of Ophthalmology, Instituto de Oftalmologia Dr Gama Pinto, Lisbon, Portugal
| | - Pedro Camacho
- Department of Ophthalmology, Instituto de Oftalmologia Dr Gama Pinto, Lisbon, Portugal
| | - Madeleine G. Purcell
- Department of Biology, Randolph-Macon College, Ashland, VA, United States of America
| | - Abbie C. Winkelmann
- Department of Biology, Randolph-Macon College, Ashland, VA, United States of America
| | - James A. Foster
- Department of Biology, Randolph-Macon College, Ashland, VA, United States of America
| | - Elena N. Pugacheva
- Department of Biochemistry, West Virginia University, Morgantown, United States of America
| | - Carlo Rivolta
- Department of Computational Biology, Unit of Medical Genetics, University of Lausanne, Lausanne, Switzerland
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
- Clinical Research Center, Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- Department of Ophthalmology, University Hospital Basel, Switzerland
- * E-mail: (CR); (VR)
| | - Visvanathan Ramamurthy
- Department of Ophthalmology, West Virginia University, Morgantown, United States of America
- Department of Biochemistry, West Virginia University, Morgantown, United States of America
- Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV, United States of America
- * E-mail: (CR); (VR)
| |
Collapse
|
15
|
Wright ZC, Loskutov Y, Murphy D, Stoilov P, Pugacheva E, Goldberg AFX, Ramamurthy V. ADP-Ribosylation Factor-Like 2 (ARL2) regulates cilia stability and development of outer segments in rod photoreceptor neurons. Sci Rep 2018; 8:16967. [PMID: 30446707 PMCID: PMC6240099 DOI: 10.1038/s41598-018-35395-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/28/2018] [Indexed: 01/31/2023] Open
Abstract
Photoreceptor cells are specialized neurons with a sensory cilium carrying an elaborate membrane structure, the outer segment (OS). Inherited mutations in genes involved in ciliogenesis frequently result in OS malformation and blindness. ADP-ribosylation factor-like 2 (ARL2) has recently been implicated in OS formation through its association with Binder of ARL2 (BART or ARL2BP), a protein linked to inherited blinding disease. To test the role of ARL2 in vision we created a transgenic mouse model expressing a tagged-dominant active form of human ARL2 (ARL2-Q70L) under a rod-specific promoter. Transgenic ARL2-Q70L animals exhibit reduced photoreceptor cell function as early as post-natal day 16 and progressive rod degeneration. We attribute loss of photoreceptor function to the defective OS morphogenesis in the ARL2-Q70L transgenic model. ARL2-Q70L expression results in shortened inner and outer segments, shortened and mislocalized axonemes and cytoplasmic accumulation of rhodopsin. In conclusion, we show that ARL2-Q70L is crucial for photoreceptor neuron sensory cilium development. Future research will expand upon our hypothesis that ARL2-Q70L mutant interferes with microtubule maintenance and tubulin regulation resulting in impaired growth of the axoneme and elaboration of the photoreceptor outer segment.
Collapse
Affiliation(s)
- Zachary C Wright
- Departments of Ophthalmology, West Virginia University, Morgantown, West Virginia, 26506, USA
| | - Yuriy Loskutov
- Departments of Biochemistry, West Virginia University, Morgantown, West Virginia, 26506, USA
| | - Daniel Murphy
- Departments of Biochemistry, West Virginia University, Morgantown, West Virginia, 26506, USA
| | - Peter Stoilov
- Departments of Biochemistry, West Virginia University, Morgantown, West Virginia, 26506, USA
| | - Elena Pugacheva
- Departments of Biochemistry, West Virginia University, Morgantown, West Virginia, 26506, USA
| | | | - Visvanathan Ramamurthy
- Departments of Ophthalmology, West Virginia University, Morgantown, West Virginia, 26506, USA. .,Departments of Biochemistry, West Virginia University, Morgantown, West Virginia, 26506, USA. .,Center for Neuroscience, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia, 26506, USA.
| |
Collapse
|