1
|
Yazdankhah M, Ghosh S, Liu H, Hose S, Zigler JS, Sinha D. Mitophagy in Astrocytes Is Required for the Health of Optic Nerve. Cells 2023; 12:2496. [PMID: 37887340 PMCID: PMC10605486 DOI: 10.3390/cells12202496] [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: 08/31/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 10/28/2023] Open
Abstract
Mitochondrial dysfunction in astrocytes has been implicated in the development of various neurological disorders. Mitophagy, mitochondrial autophagy, is required for proper mitochondrial function by preventing the accumulation of damaged mitochondria. The importance of mitophagy, specifically in the astrocytes of the optic nerve (ON), has been little studied. We introduce an animal model in which two separate mutations act synergistically to produce severe ON degeneration. The first mutation is in Cryba1, which encodes βA3/A1-crystallin, a lens protein also expressed in astrocytes, where it regulates lysosomal pH. The second mutation is in Bckdk, which encodes branched-chain ketoacid dehydrogenase kinase, which is ubiquitously expressed in the mitochondrial matrix and involved in the catabolism of the branched-chain amino acids. BCKDK is essential for mitochondrial function and the amelioration of oxidative stress. Neither of the mutations in isolation has a significant effect on the ON, but animals homozygous for both mutations (DM) exhibit very serious ON degeneration. ON astrocytes from these double-mutant (DM) animals have lysosomal defects, including impaired mitophagy, and dysfunctional mitochondria. Urolithin A can rescue the mitophagy impairment in DM astrocytes and reduce ON degeneration. These data demonstrate that efficient mitophagy in astrocytes is required for ON health and functional integrity.
Collapse
Affiliation(s)
- Meysam Yazdankhah
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (S.G.); (H.L.); (S.H.); (D.S.)
| | - Sayan Ghosh
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (S.G.); (H.L.); (S.H.); (D.S.)
| | - Haitao Liu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (S.G.); (H.L.); (S.H.); (D.S.)
| | - Stacey Hose
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (S.G.); (H.L.); (S.H.); (D.S.)
| | - J. Samuel Zigler
- Department of Ophthalmology, The Wilmer Eye Institute, The Johns Hopkins School of Medicine, Baltimore, MD 21205, USA;
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (S.G.); (H.L.); (S.H.); (D.S.)
- Department of Ophthalmology, The Wilmer Eye Institute, The Johns Hopkins School of Medicine, Baltimore, MD 21205, USA;
| |
Collapse
|
2
|
Corpuz AD, Ramos JW, Matter ML. PTRH2: an adhesion regulated molecular switch at the nexus of life, death, and differentiation. Cell Death Discov 2020; 6:124. [PMID: 33298880 PMCID: PMC7661711 DOI: 10.1038/s41420-020-00357-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/02/2020] [Accepted: 10/21/2020] [Indexed: 12/12/2022] Open
Abstract
Peptidyl-tRNA hydrolase 2 (PTRH2; Bit-1; Bit1) is an underappreciated regulator of adhesion signals and Bcl2 expression. Its key roles in muscle differentiation and integrin-mediated signaling are central to the pathology of a recently identified patient syndrome caused by a cluster of Ptrh2 gene mutations. These loss-of-function mutations were identified in patients presenting with severe deleterious phenotypes of the skeletal muscle, endocrine, and nervous systems resulting in a syndrome called Infantile-onset Multisystem Nervous, Endocrine, and Pancreatic Disease (IMNEPD). In contrast, in cancer PTRH2 is a potential oncogene that promotes malignancy and metastasis. PTRH2 modulates PI3K/AKT and ERK signaling in addition to Bcl2 expression and thereby regulates key cellular processes in response to adhesion including cell survival, growth, and differentiation. In this Review, we discuss the state of the science on this important cell survival, anoikis and differentiation regulator, and opportunities for further investigation and translation. We begin with a brief overview of the structure, regulation, and subcellular localization of PTRH2. We discuss the cluster of gene mutations thus far identified which cause developmental delays and multisystem disease. We then discuss the role of PTRH2 and adhesion in breast, lung, and esophageal cancers focusing on signaling pathways involved in cell survival, cell growth, and cell differentiation.
Collapse
Affiliation(s)
- Austin D Corpuz
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, 96813, HI, USA.,Cell and Molecular Biology Graduate Program, John A. Burns School of Medicine University of Hawaii at Mānoa, Honolulu, HI, 96813, USA
| | - Joe W Ramos
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, 96813, HI, USA
| | - Michelle L Matter
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, 96813, HI, USA.
| |
Collapse
|
3
|
Ghosh S, Padmanabhan A, Vaidya T, Watson AM, Bhutto IA, Hose S, Shang P, Stepicheva N, Yazdankhah M, Weiss J, Das M, Gopikrishna S, Aishwarya, Yadav N, Berger T, Mak TW, Xia S, Qian J, Lutty GA, Jayagopal A, Zigler JS, Sethu S, Handa JT, Watkins SC, Ghosh A, Sinha D. Neutrophils homing into the retina trigger pathology in early age-related macular degeneration. Commun Biol 2019; 2:348. [PMID: 31552301 PMCID: PMC6754381 DOI: 10.1038/s42003-019-0588-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 08/27/2019] [Indexed: 12/12/2022] Open
Abstract
Age-related macular degeneration (AMD) is an expanding problem as longevity increases worldwide. While inflammation clearly contributes to vision loss in AMD, the mechanism remains controversial. Here we show that neutrophils are important in this inflammatory process. In the retinas of both early AMD patients and in a mouse model with an early AMD-like phenotype, we show neutrophil infiltration. Such infiltration was confirmed experimentally using ribbon-scanning confocal microscopy (RSCM) and IFNλ- activated dye labeled normal neutrophils. With neutrophils lacking lipocalin-2 (LCN-2), infiltration was greatly reduced. Further, increased levels of IFNλ in early AMD trigger neutrophil activation and LCN-2 upregulation. LCN-2 promotes inflammation by modulating integrin β1 levels to stimulate adhesion and transmigration of activated neutrophils into the retina. We show that in the mouse model, inhibiting AKT2 neutralizes IFNλ inflammatory signals, reduces LCN-2-mediated neutrophil infiltration, and reverses early AMD-like phenotype changes. Thus, AKT2 inhibitors may have therapeutic potential in early, dry AMD.
Collapse
Affiliation(s)
- Sayan Ghosh
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | | | | | - Alan M. Watson
- Center for Biologic Imaging and Department of Cellular Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Imran A. Bhutto
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Stacey Hose
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Peng Shang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Nadezda Stepicheva
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Meysam Yazdankhah
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Joseph Weiss
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | | | | | - Aishwarya
- Narayana Nethralaya Foundation, Bengaluru, India
| | - Naresh Yadav
- Narayana Nethralaya Foundation, Bengaluru, India
| | - Thorsten Berger
- The Campbell Family Institute for Breast Cancer Research and Ontario Cancer Institute, University Health Network, Toronto, ON Canada
| | - Tak W. Mak
- The Campbell Family Institute for Breast Cancer Research and Ontario Cancer Institute, University Health Network, Toronto, ON Canada
| | - Shuli Xia
- Hugo W. Moser Research Institute at Kennedy Krieger, Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Jiang Qian
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Gerard A. Lutty
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Ashwath Jayagopal
- Pharma Research and Early Development, Roche Innovation Center, F. Hoffmann-La Roche, Ltd, Basel, Switzerland
- Present Address: Kodiak Sciences, Palo Alto, CA USA
| | - J. Samuel Zigler
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | | | - James T. Handa
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Simon C. Watkins
- Center for Biologic Imaging and Department of Cellular Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | | | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| |
Collapse
|
4
|
Caolo V, Roblain Q, Lecomte J, Carai P, Peters L, Cuijpers I, Robinson EL, Derks K, Sergeys J, Noël A, Jones EAV, Moons L, Heymans S. Resistance to retinopathy development in obese, diabetic and hypertensive ZSF1 rats: an exciting model to identify protective genes. Sci Rep 2018; 8:11922. [PMID: 30093686 PMCID: PMC6085379 DOI: 10.1038/s41598-018-29812-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/17/2018] [Indexed: 12/11/2022] Open
Abstract
Diabetic retinopathy (DR) is one of the major complications of diabetes, which eventually leads to blindness. Up to date, no animal model has yet shown all the co-morbidities often observed in DR patients. Here, we investigated whether obese 42 weeks old ZSF1 rat, which spontaneously develops diabetes, hypertension and obesity, would be a suitable model to study DR. Although arteriolar tortuosity increased in retinas from obese as compared to lean (hypertensive only) ZSF1 rats, vascular density pericyte coverage, microglia number, vascular morphology and retinal thickness were not affected by diabetes. These results show that, despite high glucose levels, obese ZSF1 rats did not develop DR. Such observations prompted us to investigate whether the expression of genes, possibly able to contain DR development, was affected. Accordingly, mRNA sequencing analysis showed that genes (i.e. Npy and crystallins), known to have a protective role, were upregulated in retinas from obese ZSF1 rats. Lack of retina damage, despite obesity, hypertension and diabetes, makes the 42 weeks of age ZSF1 rats a suitable animal model to identify genes with a protective function in DR. Further characterisation of the identified genes and downstream pathways could provide more therapeutic targets for the treat DR.
Collapse
Affiliation(s)
- Vincenza Caolo
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Belgium.
| | - Quentin Roblain
- Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.,Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liège, Liège, Belgium
| | - Julie Lecomte
- Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liège, Liège, Belgium
| | - Paolo Carai
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Belgium
| | - Linsey Peters
- Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Ilona Cuijpers
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Belgium.,Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Emma Louise Robinson
- Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Kasper Derks
- Department of Genetics and Cell Biology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Jurgen Sergeys
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Agnès Noël
- Laboratory of Tumor and Development Biology, GIGA-Cancer, University of Liège, Liège, Belgium
| | - Elizabeth A V Jones
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Stephane Heymans
- Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, KU Leuven, Belgium.,Department of Cardiology, CARIM School for Cardiovascular Diseases Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.,The Netherlands Heart Institute, Nl-HI, Utrecht, The Netherlands
| |
Collapse
|
5
|
Vrolyk V, Haruna J, Benoit-Biancamano MO. Neonatal and Juvenile Ocular Development in Sprague-Dawley Rats: A Histomorphological and Immunohistochemical Study. Vet Pathol 2017; 55:310-330. [DOI: 10.1177/0300985817738098] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
As in many altricial species, rats are born with fused eyelids and markedly underdeveloped eyes. While the normal histology of the eyes of mature rats is known, the histomorphological changes occurring during postnatal eye development in this species remain incompletely characterized. This study was conducted to describe the postnatal development of ocular structures in Sprague-Dawley (SD) rats during the first month of age using histology and immunohistochemistry (IHC). Both eyes were collected from 51 SD rats at 13 time points between postnatal day (PND)1 and PND30. Histologic examination of hematoxylin and eosin-stained sections was performed, as well as IHC for cleaved-caspase-3 and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) to evaluate apoptosis, and IHC for Ki-67 and phospho-histone-H3 to evaluate cell proliferation. Extensive ocular tissue remodeling occurred prior to the eyelid opening around PND14 and reflected the interplay between apoptosis and cell proliferation. Apoptosis was particularly remarkable in the maturing subcapsular anterior epithelium of the lens, the inner nuclear and ganglion cell layers of the developing retina, and the Harderian gland, and was involved in the regression of the hyaloid vasculature. Nuclear degradation in the newly formed secondary lens fibers was noteworthy after birth and was associated with TUNEL-positive nuclear remnants lining the lens organelle-free zone. Cell proliferation was marked in the developing retina, cornea, iris, ciliary body and Harderian gland. The rat eye reached histomorphological maturity at PND21 after a rapid phase of morphological changes characterized by the coexistence of cell death and proliferation.
Collapse
Affiliation(s)
- Vanessa Vrolyk
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | | | - Marie-Odile Benoit-Biancamano
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
- Groupe de recherche en pharmacologie animale du Québec (GREPAQ), Faculty of Veterinary Medicne University of Montreal, Saint-Hyacinthe, QC, Canada
| |
Collapse
|
6
|
Van Cruchten S, Vrolyk V, Perron Lepage MF, Baudon M, Voute H, Schoofs S, Haruna J, Benoit-Biancamano MO, Ruot B, Allegaert K. Pre- and Postnatal Development of the Eye: A Species Comparison. Birth Defects Res 2017; 109:1540-1567. [PMID: 28941218 DOI: 10.1002/bdr2.1100] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 07/07/2017] [Indexed: 12/26/2022]
Abstract
In this review paper, literature data on pre- and postnatal eye development are compared between humans and nonclinical species that are commonly used for human safety assessment, namely, mouse, rat, rabbit, dog, minipig, and nonhuman primates. Some new data on rat and minipig ocular development are also included. This compiled information can be helpful for species selection in juvenile toxicity studies or assist in the interpretation of (non)clinical data during pediatric drug development. Despite some differences in developmental windows and anatomical peculiarities, such as the lack of a fovea centralis in nonprimate species or the presence of a nictitating membrane in some nonclinical species, the functioning and development of the eye is strikingly similar between humans and other mammals. As such, all commonly used nonclinical species appear to be relatively good models for human eye development, although some practical constraints such as size may be a limiting factor. Birth Defects Research 109:1540-1567, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Steven Van Cruchten
- Applied Veterinary Morphology, Department of Veterinary Sciences, University of Antwerp, Wilrijk, Belgium
| | - Vanessa Vrolyk
- Département de pathologie et microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Canada
| | | | - Marie Baudon
- Charles River, Safety Assessment, Saint-Germain-Nuelles, Lyon, France
| | - Hélène Voute
- Charles River, Safety Assessment, Saint-Germain-Nuelles, Lyon, France
| | | | | | - Marie-Odile Benoit-Biancamano
- Département de pathologie et microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Canada
| | - Benoît Ruot
- Charles River, Safety Assessment, Saint-Germain-Nuelles, Lyon, France
| | - Karel Allegaert
- Intensive Care and Department of Surgery, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands.,Department of development and regeneration, KU Leuven, Leuven, Belgium
| |
Collapse
|
7
|
Zigler JS, Hodgkinson CA, Wright M, Klise A, Sundin O, Broman KW, Hejtmancik F, Huang H, Patek B, Sergeev Y, Hose S, Brayton C, Xaiodong J, Vasquez D, Maragakis N, Mori S, Goldman D, Hoke A, Sinha D. A Spontaneous Missense Mutation in Branched Chain Keto Acid Dehydrogenase Kinase in the Rat Affects Both the Central and Peripheral Nervous Systems. PLoS One 2016; 11:e0160447. [PMID: 27472223 PMCID: PMC4966912 DOI: 10.1371/journal.pone.0160447] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/19/2016] [Indexed: 11/19/2022] Open
Abstract
A novel mutation, causing a phenotype we named frogleg because its most obvious characteristic is a severe splaying of the hind limbs, arose spontaneously in a colony of Sprague-Dawley rats. Frogleg is a complex phenotype that includes abnormalities in hind limb function, reduced brain weight with dilated ventricles and infertility. Using micro-satellite markers spanning the entire rat genome, the mutation was mapped to a region of rat chromosome 1 between D1Rat131 and D1Rat287. Analysis of whole genome sequencing data within the linkage interval, identified a missense mutation in the branched-chain alpha-keto dehydrogenase kinase (Bckdk) gene. The protein encoded by Bckdk is an integral part of an enzyme complex located in the mitochondrial matrix of many tissues which regulates the levels of the branched-chain amino acids (BCAAs), leucine, isoleucine and valine. BCAAs are essential amino acids (not synthesized by the body), and circulating levels must be tightly regulated; levels that are too high or too low are both deleterious. BCKDK phosphorylates Ser293 of the E1α subunit of the BCKDH protein, which catalyzes the rate-limiting step in the catabolism of the BCAAs, inhibiting BCKDH and thereby, limiting breakdown of the BCAAs. In contrast, when Ser293 is not phosphorylated, BCKDH activity is unchecked and the levels of the BCAAs will decrease dramatically. The mutation is located within the kinase domain of Bckdk and is predicted to be damaging. Consistent with this, we show that in rats homozygous for the mutation, phosphorylation of BCKDH in the brain is markedly decreased relative to wild type or heterozygous littermates. Further, circulating levels of the BCAAs are reduced by 70-80% in animals homozygous for the mutation. The frogleg phenotype shares important characteristics with a previously described Bckdk knockout mouse and with human subjects with Bckdk mutations. In addition, we report novel data regarding peripheral neuropathy of the hind limbs.
Collapse
Affiliation(s)
- J. Samuel Zigler
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Colin A. Hodgkinson
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, United States of America
| | - Megan Wright
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Andrew Klise
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Olof Sundin
- Department of Biomedical Sciences, Texas Tech University Health Science Center, El Paso, TX, United States of America
| | - Karl W. Broman
- Department of Biostatistics & Informatics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America
| | - Fielding Hejtmancik
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Hao Huang
- Department of Radiology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Bonnie Patek
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Yuri Sergeev
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Stacey Hose
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Cory Brayton
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Jiao Xaiodong
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - David Vasquez
- Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Nicholas Maragakis
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Susumu Mori
- Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - David Goldman
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, United States of America
| | - Ahmet Hoke
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Debasish Sinha
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| |
Collapse
|
8
|
Establishment of a recessive mutant small-eye rat with lens involution and retinal detachment associated with partial deletion and rearrangement of the Cryba1 gene. Biochem J 2015; 471:293-305. [PMID: 26303524 DOI: 10.1042/bj20150165] [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: 02/09/2015] [Accepted: 08/24/2015] [Indexed: 11/17/2022]
Abstract
From our stock of SDRs (Sprague-Dawley rats), we established a mutant strain having small opaque eyes and named it HiSER (Hirosaki small-eye rat). The HiSER phenotype is progressive and autosomal recessive. In HiSER eyes, disruption and involution of the lens, thickening of the inner nuclear layer, detachment and aggregation of the retina, rudimentary muscle in the ciliary body and cell infiltration in the vitreous humour were observed. Genetic linkage analysis using crossing with Brown Norway rat suggested that the causative gene(s) is located on chromosome 10. Microarray analysis showed that the expression level of the Cryba1 gene encoding βA3/A1-crystallin on chromosome 10 was markedly decreased in HiSER eyes. Genomic PCR revealed deletion of a 3.6-kb DNA region encompassing exons 4-6 of the gene in HiSERs. In HiSER eyes, a chimaeric transcript of the gene containing exons 1-3 and an approximately 250-bp sequence originating from the 3'-UTR of the Nufip2 gene, located downstream of the breakpoint in the opposite direction, was present. Whereas the chimaeric transcript was expressed in HiSER eyes, neither normal nor chimaeric βA3/A1-crystallin proteins were detected by Western blot analysis. Real-time RT (reverse transcription)-PCR analysis revealed that expression level of the Nufip2 gene in the HiSER eye was 40% of that in the SDR eye. These results suggest that the disappearance of the βA3/A1-crystallin protein and, in addition, down-regulation of the Nufip2 gene as a consequence of gene rearrangement causes the HiSER phenotype.
Collapse
|
9
|
Zigler JS, Sinha D. βA3/A1-crystallin: more than a lens protein. Prog Retin Eye Res 2014; 44:62-85. [PMID: 25461968 DOI: 10.1016/j.preteyeres.2014.11.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/31/2014] [Accepted: 11/04/2014] [Indexed: 12/19/2022]
Abstract
Crystallins, the highly abundant proteins of the ocular lens, are essential determinants of the transparency and refractivity required for lens function. Initially thought to be lens-specific and to have evolved as lens proteins, it is now clear that crystallins were recruited to the lens from proteins that existed before lenses evolved. Crystallins are expressed outside of the lens and most have been shown to have cellular functions distinct from their roles as structural elements in the lens. For one major crystallin group, the β/γ-crystallin superfamily, no such functions have yet been established. We have explored possible functions for the polypeptides (βA3-and βA1-crystallins) encoded by Cryba1, one of the 6 β-crystallin genes, using a spontaneous rat mutant and genetically engineered mouse models. βA3-and βA1-crystallins are expressed in retinal astrocytes and retinal pigment epithelial (RPE) cells. In both cell types, these proteins appear to be required for the proper acidification of the lysosomes. In RPE cells, elevated pH in the lysosomes is shown to impair the critical processes of phagocytosis and autophagy, leading to accumulation of undigested cargo in (auto) phagolysosomes. We postulate that this accumulation may cause pathological changes in the cells resembling some of those characteristic of age-related macular degeneration (AMD). Our studies suggest an important regulatory function of βA3/A1-crystallin in astrocytes. We provide evidence that the cellular function of βA3/A1-crystallin involves its interaction with V-ATPase, the proton pump responsible for acidification of the endolysosomal system.
Collapse
Affiliation(s)
- J Samuel Zigler
- The Johns Hopkins University School of Medicine, The Wilmer Eye Institute, 400 North Broadway, Smith Building Room M037, Baltimore, MD 21231, USA.
| | - Debasish Sinha
- The Johns Hopkins University School of Medicine, The Wilmer Eye Institute, 400 North Broadway, Smith Building Room M035, Baltimore, MD 21231, USA.
| |
Collapse
|
10
|
Impaired endolysosomal function disrupts Notch signalling in optic nerve astrocytes. Nat Commun 2013; 4:1629. [PMID: 23535650 DOI: 10.1038/ncomms2624] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 02/20/2013] [Indexed: 12/28/2022] Open
Abstract
Astrocytes migrate from the optic nerve into the inner retina, forming a template upon which retinal vessels develop. In the Nuc1 rat, mutation in the gene encoding βA3/A1-crystallin disrupts both Notch signalling in astrocytes and formation of the astrocyte template. Here we show that loss of βA3/A1-crystallin in astrocytes does not impede Notch ligand binding or extracellular cleavages. However, it affects vacuolar-type proton ATPase (V-ATPase) activity, thereby compromising acidification of the endolysosomal compartments, leading to reduced γ-secretase-mediated processing and release of the Notch intracellular domain (NICD). Lysosomal-mediated degradation of Notch is also impaired. These defects decrease the level of NICD in the nucleus, inhibiting the expression of Notch target genes. Overexpression of βA3/A1-crystallin in those same astrocytes restored V-ATPase activity and normal endolysosomal acidification, thereby increasing the levels of γ-secretase to facilitate optimal Notch signalling. We postulate that βA3/A1-crystallin is essential for normal endolysosomal acidification, and thereby, normal activation of Notch signalling in astrocytes.
Collapse
|
11
|
Comprehensive review on the HSC70 functions, interactions with related molecules and involvement in clinical diseases and therapeutic potential. Pharmacol Ther 2012; 136:354-74. [PMID: 22960394 DOI: 10.1016/j.pharmthera.2012.08.014] [Citation(s) in RCA: 193] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 08/14/2012] [Indexed: 12/28/2022]
Abstract
Heat shock cognate protein 70 (HSC70) is a constitutively expressed molecular chaperone which belongs to the heat shock protein 70 (HSP70) family. HSC70 shares some of the structural and functional similarity with HSP70. HSC70 also has different properties compared with HSP70 and other heat shock family members. HSC70 performs its full functions by the cooperation of co-chaperones. It interacts with many other molecules as well and regulates various cellular functions. It is also involved in various diseases and may become a biomarker for diagnosis and potential therapeutic targets for design, discovery, and development of novel drugs to treat various diseases. In this article, we provide a comprehensive review on HSC70 from the literatures including the basic general information such as classification, structure and cellular location, genetics and function, as well as its protein association and interaction with other proteins. In addition, we also discussed the relationship of HSC70 and related clinical diseases such as cancer, cardiovascular, neurological, hepatic and many other diseases and possible therapeutic potential and highlight the progress and prospects of research in this field. Understanding the functions of HSC70 and its interaction with other molecules will help us to reveal other novel properties of this protein. Scientists may be able to utilize this protein as a biomarker and therapeutic target to make significant advancement in scientific research and clinical setting in the future.
Collapse
|
12
|
Sinha D, Valapala M, Bhutto I, Patek B, Zhang C, Hose S, Yang F, Cano M, Stark WJ, Lutty GA, Zigler JS, Wawrousek EF. βA3/A1-crystallin is required for proper astrocyte template formation and vascular remodeling in the retina. Transgenic Res 2012; 21:1033-42. [PMID: 22427112 DOI: 10.1007/s11248-012-9608-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 02/27/2012] [Indexed: 11/30/2022]
Abstract
Nuc1 is a spontaneous rat mutant resulting from a mutation in the Cryba1 gene, coding for βA3/A1-crystallin. Our earlier studies with Nuc1 provided novel evidence that astrocytes, which express βA3/A1-crystallin, have a pivotal role in retinal remodeling. The role of astrocytes in the retina is only beginning to be explored. One of the limitations in the field is the lack of appropriate animal models to better investigate the function of astrocytes in retinal health and disease. We have now established transgenic mice that overexpress the Nuc1 mutant form of Cryba1, specifically in astrocytes. Astrocytes in wild type mice show normal compact stellate structure, producing a honeycomb-like network. In contrast, in transgenics over-expressing the mutant (Nuc1) Cryba1 in astrocytes, bundle-like structures with abnormal patterns and morphology were observed. In the nerve fiber layer of the transgenic mice, an additional layer of astrocytes adjacent to the vitreous is evident. This abnormal organization of astrocytes affects both the superficial and deep retinal vascular density and remodeling. Fluorescein angiography showed increased venous dilation and tortuosity of branches in the transgenic retina, as compared to wild type. Moreover, there appear to be fewer interactions between astrocytes and endothelial cells in the transgenic retina than in normal mouse retina. Further, astrocytes overexpressing the mutant βA3/A1-crystallin migrate into the vitreous, and ensheath the hyaloid artery, in a manner similar to that seen in the Nuc1 rat. Together, these data demonstrate that developmental abnormalities of astrocytes can affect the normal remodeling process of both fetal and retinal vessels of the eye and that βA3/A1-crystallin is essential for normal astrocyte function in the retina.
Collapse
Affiliation(s)
- Debasish Sinha
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 North Broadway, Baltimore, MD, 21231, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Ma B, Sen T, Asnaghi L, Valapala M, Yang F, Hose S, McLeod DS, Lu Y, Eberhart C, Zigler JS, Sinha D. βA3/A1-Crystallin controls anoikis-mediated cell death in astrocytes by modulating PI3K/AKT/mTOR and ERK survival pathways through the PKD/Bit1-signaling axis. Cell Death Dis 2011; 2:e217. [PMID: 21993393 PMCID: PMC3219085 DOI: 10.1038/cddis.2011.100] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
During eye development, apoptosis is vital to the maturation of highly specialized structures such as the lens and retina. Several forms of apoptosis have been described, including anoikis, a form of apoptosis triggered by inadequate or inappropriate cell–matrix contacts. The anoikis regulators, Bit1 (Bcl-2 inhibitor of transcription-1) and protein kinase-D (PKD), are expressed in developing lens when the organelles are present in lens fibers, but are downregulated as active denucleation is initiated. We have previously shown that in rats with a spontaneous mutation in the Cryba1 gene, coding for βA3/A1-crystallin, normal denucleation of lens fibers is inhibited. In rats with this mutation (Nuc1), both Bit1 and PKD remain abnormally high in lens fiber cells. To determine whether βA3/A1-crystallin has a role in anoikis, we induced anoikis in vitro and conducted mechanistic studies on astrocytes, cells known to express βA3/A1-crystallin. The expression pattern of Bit1 in retina correlates temporally with the development of astrocytes. Our data also indicate that loss of βA3/A1-crystallin in astrocytes results in a failure of Bit1 to be trafficked to the Golgi, thereby suppressing anoikis. This loss of βA3/A1-crystallin also induces insulin-like growth factor-II, which increases cell survival and growth by modulating the phosphatidylinositol-3-kinase (PI3K)/AKT/mTOR and extracellular signal-regulated kinase pathways. We propose that βA3/A1-crystallin is a novel regulator of both life and death decisions in ocular astrocytes.
Collapse
Affiliation(s)
- B Ma
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
A developmental defect in astrocytes inhibits programmed regression of the hyaloid vasculature in the mammalian eye. Eur J Cell Biol 2011; 90:440-8. [PMID: 21354650 DOI: 10.1016/j.ejcb.2011.01.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 01/07/2011] [Accepted: 01/09/2011] [Indexed: 11/21/2022] Open
Abstract
Previously we reported the novel observation that astrocytes ensheath the persistent hyaloid artery, both in the Nuc1 spontaneous mutant rat, and in human PFV (persistent fetal vasculature) disease (Developmental Dynamics 234:36-47, 2005). We now show that astrocytes isolated from both the optic nerve and retina of Nuc1 rats migrate faster than wild type astrocytes. Aquaporin 4 (AQP4), the major water channel in astrocytes, has been shown to be important in astrocyte migration. We demonstrate that AQP4 expression is elevated in the astrocytes in PFV conditions, and we hypothesize that this causes the cells to migrate abnormally into the vitreous where they ensheath the hyaloid artery. This abnormal association of astrocytes with the hyaloid artery may impede the normal macrophage-mediated remodeling and regression of the hyaloid system.
Collapse
|
15
|
Zigler JS, Zhang C, Grebe R, Sehrawat G, Hackler L, Adhya S, Hose S, McLeod DS, Bhutto I, Barbour W, Parthasarathy G, Zack DJ, Sergeev Y, Lutty GA, Handa JT, Sinha D. Mutation in the βA3/A1-crystallin gene impairs phagosome degradation in the retinal pigmented epithelium of the rat. J Cell Sci 2011; 124:523-31. [PMID: 21266465 DOI: 10.1242/jcs.078790] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Phagocytosis of the shed outer segment discs of photoreceptors is a major function of the retinal pigmented epithelium (RPE). We demonstrate for the first time that βA3/A1-crystallin, a major structural protein of the ocular lens, is expressed in RPE cells. Further, by utilizing the Nuc1 rat, in which the βA3/A1-crystallin gene is mutated, we show that this protein is required by RPE cells for proper degradation of outer segment discs that have been internalized in phagosomes. We also demonstrate that in wild-type RPE, βA3/A1-crystallin is localized to the lysosomes. However, in the Nuc1 RPE, βA3/A1-crystallin fails to translocate to the lysosomes, perhaps because misfolding of the mutant protein masks sorting signals required for proper trafficking. The digestion of phagocytized outer segments requires a high level of lysosomal enzyme activity, and cathepsin D, the major enzyme responsible for proteolysis of the outer segments, is decreased in mutant RPE cells. Interestingly, our results also indicate a defect in the autophagy process in the Nuc1 RPE, which is probably also linked to impaired lysosomal function, because phagocytosis and autophagy might share common mechanisms in degradation of their targets. βA3/A1-crystallin is a novel lysosomal protein in RPE, essential for degradation of phagocytosed material.
Collapse
Affiliation(s)
- J Samuel Zigler
- The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Parthasarathy G, Ma B, Zhang C, Gongora C, Samuel Zigler J, Duncan MK, Sinha D. Expression of βA3/A1-crystallin in the developing and adult rat eye. J Mol Histol 2011; 42:59-69. [PMID: 21203897 DOI: 10.1007/s10735-010-9307-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 12/21/2010] [Indexed: 11/27/2022]
Abstract
Crystallins are very abundant structural proteins of the lens and are also expressed in other tissues. We have previously reported a spontaneous mutation in the rat βA3/A1-crystallin gene, termed Nuc1, which has a novel, complex, ocular phenotype. The current study was undertaken to compare the expression pattern of this gene during eye development in wild type and Nuc1 rats by in situ hybridization (ISH) and immunohistochemistry (IHC). βA3/A1-crystallin expression was first detected in the eyes of both wild type and Nuc1 rats at embryonic (E) day 12.5 in the posterior portion of the lens vesicle, and remained limited to the lens fibers throughout fetal life. After birth, βA3/A1-crystallin expression was also detected in the neural retina (specifically in the astrocytes and ganglion cells) and in the retinal pigmented epithelium (RPE). This suggested that βA3/A1-crystallin is not only a structural protein of the lens, but has cellular function(s) in other ocular tissues. In summary, expression of βA3/A1-crystallin is controlled differentially in various eye tissues with lens being the site of greatest expression. Similar staining patterns, detected by ISH and IHC, in wild type and Nuc1 animals suggest that functional differences in the protein, rather than changes in mRNA/protein level of expression, likely account for developmental abnormalities in Nuc1.
Collapse
Affiliation(s)
- Geetha Parthasarathy
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 N. Broadway, Smith Research Building, M035, Baltimore, MD 21287, USA
| | | | | | | | | | | | | |
Collapse
|
17
|
On the mechanism of organelle degradation in the vertebrate lens. Exp Eye Res 2008; 88:133-9. [PMID: 18840431 DOI: 10.1016/j.exer.2008.08.017] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 08/22/2008] [Accepted: 08/26/2008] [Indexed: 11/20/2022]
Abstract
The programmed elimination of cytoplasmic organelles occurs during terminal differentiation of erythrocytes, keratinocytes and lens fiber cells. In each case, the process is relatively well understood phenomenologically, but the underlying molecular mechanisms have been surprisingly slow to emerge. This brief review considers the particular case of the lens where, in addition to their specialized physiological roles, organelles represent potential sources of light scattering. The article describes how the elimination of organelles from lens cells located on the visual axis contributes to the transparency of lens tissue. Classic anatomical studies of lens organelle degradation are discussed, along with more contemporary work utilizing confocal microscopy and other imaging modalities. Finally, recent data on the biochemistry of organelle degradation are reviewed. Several review articles on lens organelle degradation are available [Wride, M.A., 1996. Cellular and molecular features of lens differentiation: a review of recent advances. Differentiation 61, 77-93; Wride, M.A., 2000. Minireview: apoptosis as seen through a lens. Apoptosis 5, 203-209; Bassnett, S., 2002. Lens organelle degradation. Exp. Eye Res. 74, 1-6; Dahm, R., 2004. Dying to see. Sci. Am. 291, 82-89] and readers are directed to these for a comprehensive discussion of the earlier literature on this topic.
Collapse
|
18
|
Sinha D, Klise A, Sergeev Y, Hose S, Bhutto IA, Hackler L, Malpic-Llanos T, Samtani S, Grebe R, Goldberg MF, Hejtmancik JF, Nath A, Zack DJ, Fariss RN, McLeod DS, Sundin O, Broman KW, Lutty GA, Zigler JS. betaA3/A1-crystallin in astroglial cells regulates retinal vascular remodeling during development. Mol Cell Neurosci 2007; 37:85-95. [PMID: 17931883 DOI: 10.1016/j.mcn.2007.08.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Accepted: 08/24/2007] [Indexed: 11/25/2022] Open
Abstract
Vascular remodeling is a complex process critical to development of the mature vascular system. Astrocytes are known to be indispensable for initial formation of the retinal vasculature; our studies with the Nuc1 rat provide novel evidence that these cells are also essential in the retinal vascular remodeling process. Nuc1 is a spontaneous mutation in the Sprague-Dawley rat originally characterized by nuclear cataracts in the heterozygote and microphthalmia in the homozygote. We report here that the Nuc1 allele results from mutation of the betaA3/A1-crystallin gene, which in the neural retina is expressed only in astrocytes. We demonstrate striking structural abnormalities in Nuc1 astrocytes with profound effects on the organization of intermediate filaments. While vessels form in the Nuc1 retina, the subsequent remodeling process required to provide a mature vascular network is deficient. Our data implicate betaA3/A1-crystallin as an important regulatory factor mediating vascular patterning and remodeling in the retina.
Collapse
Affiliation(s)
- Debasish Sinha
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Bunting-Blaustein Cancer Research Building II, 1550 Orleans St., Room 146, Baltimore, MD 21231, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Gehlbach P, Hose S, Lei B, Zhang C, Cano M, Arora M, Neal R, Barnstable C, Goldberg MF, Zigler JS, Sinha D. Developmental abnormalities in the Nuc1 rat retina: a spontaneous mutation that affects neuronal and vascular remodeling and retinal function. Neuroscience 2005; 137:447-61. [PMID: 16289888 DOI: 10.1016/j.neuroscience.2005.08.084] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Revised: 08/17/2005] [Accepted: 08/30/2005] [Indexed: 11/18/2022]
Abstract
The retina serves as an excellent model in which to study vertebrate CNS development. We have discovered a spontaneous mutation in the Sprague-Dawley rat that results in a novel and unusual ocular phenotype, including retinal abnormalities, that we have named Nuc1. We have previously shown that the Nuc1 mutation appears to suppress programmed cell death in the developing retina. Here we report that maturation of both the retinal neurons and the retinal vessels is abnormal in Nuc1 homozygous rats. The developmental changes in the retinal neurons and vasculature are correlated with regard to degree of abnormality. As Nuc1 homozygotes mature, focal retinal detachment begins at approximately 3 months after birth, and near total traction retinal detachment, associated with pre-retinal fibrosis and neovascularization, is evident by 18 months. Electroretinographic studies at 2.5 months of age indicate that functional retinal degeneration precedes retinal detachment. The functional abnormality is most evident in rods and the inner retina, and is present in homozygous but not heterozygous mutants. Immunocytochemical studies of rod and cone photoreceptors indicate abnormalities in rod, but not cone, photoreceptors in Nuc1 homozygotes, consistent with the electroretinographic findings. In Nuc1 animals, the Muller cells are activated. Although such activation may result from inflammation, Muller cells in Nuc1 may be reacting to a neuronal influence. It appears that the Nuc1 mutation plays a regulatory role in both developing and maturing ocular tissues. The Nuc1 mutation may also serve as an important genetic tool to explore the relationships that may exist among gliosis, normal neuronal development, and normal vascular development and how abnormalities in these associations lead to common retinal diseases.
Collapse
Affiliation(s)
- P Gehlbach
- Department of Ophthalmology, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Hose S, Zigler JS, Sinha D. A novel rat model to study the functions of macrophages during normal development and pathophysiology of the eye. Immunol Lett 2005; 96:299-302. [PMID: 15585337 DOI: 10.1016/j.imlet.2004.09.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2004] [Revised: 09/16/2004] [Accepted: 09/20/2004] [Indexed: 11/17/2022]
Abstract
Several studies have shown that macrophages play an active role in the initiation and completion of the programmed cell death process during development. Macrophages are called professional phagocytes, as their primary role is phagocytosis. The process of phagocytosis is complex and to date only poorly defined. It has also been postulated that macrophages around the developing lens likely migrate into the neural retina and differentiate into microglia after completion of their role as debris removers. We have identified ED1 immunopositive macrophages and CD11b/18 (OX-42) immunopositive macrophage-like cells in the vitreous chamber and sub-retinal space of a rat spontaneous mutation that we have termed Nuc1. The mutation appears to affect the programmed cell death process and is highly eye specific in its effects. While ED1 and ED2-immunopositive macrophages have previously been found surrounding the developing lens and are thought to play a role in the programmed regression of the tunica vasculosa lentis (part of the vascular structure present on the posterior surface of the lens during development), OX-42-immunopositive cells have not previously been identified in the vitreous chamber under normal or pathological conditions. Macrophage subpopulations surrounding the lens may differentiate into OX-42+ cells in Nuc1 following the release of lens material into the vitreous after the posterior capsule ruptures. In Nuc1 homozygotes, the posterior lens capsule ruptures before birth, causing lens material to be extruded into the vitreous compartment and damaging the tunica vasculosa lentis. Alternatively, OX-42+ cells may be recruited due to an inflammatory response both in the vitreous compartment and sub-retinal space. Inflammation is known to have an enhanced influx of phagocytic cells. Our data suggests that subpopulations of macrophages perform distinct functions in inducing apoptosis and phagocytic activity during normal conditions and in disease.
Collapse
Affiliation(s)
- Stacey Hose
- Department of Ophthalmology, School of Medicine, The Johns Hopkins University, 600 North Wolfe Street/Jefferson 3-127A, Baltimore, MD 21287, USA
| | | | | |
Collapse
|
21
|
Zhang C, Gehlbach P, Gongora C, Cano M, Fariss R, Hose S, Nath A, Green WR, Goldberg MF, Zigler JS, Sinha D. A potential role for β- and γ-crystallins in the vascular remodeling of the eye. Dev Dyn 2005; 234:36-47. [PMID: 16003775 DOI: 10.1002/dvdy.20494] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We demonstrate that expression of beta- and gamma-crystallins is associated with intraocular vessels during normal vascular development of the eye and also in the Nuc1 rat, a mutant in which the hyaloid vascular system fails to regress normally. Real-Time RT PCR, Western blot and metabolic labeling studies indicate an increased expression of beta- and gamma-crystallins in Nuc1 retina. The increased expression of crystallins was localized to the astrocytes surrounding the intraocular vessels. A similar pattern of crystallin expression was also observed in the retinal vessels during normal development. Cultured human astrocytes exposed to 3-nitropropionic acid, an established model of neuronal hypoxia, increased VEGF expression, as expected, but also increased expression of crystallins. Our data suggest that crystallins may function together with VEGF during vascular remodeling. Interestingly, in human PFV (persistent fetal vasculature) disease, where the hyaloid vasculature abnormally persists after birth, we show that astrocytes express both VEGF and crystallins.
Collapse
Affiliation(s)
- Cheng Zhang
- Department of Ophthalmology, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|