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Liu C, Tang J, Chen Y, Zhang Q, Lin J, Wu S, Han J, Liu Z, Wu C, Zhuo Y, Li Y. Intracellular Zn 2+ promotes extracellular matrix remodeling in dexamethasone-treated trabecular meshwork. Am J Physiol Cell Physiol 2024; 326:C1293-C1307. [PMID: 38525543 DOI: 10.1152/ajpcell.00725.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/26/2024] [Accepted: 03/09/2024] [Indexed: 03/26/2024]
Abstract
Given the widespread application of glucocorticoids in ophthalmology, the associated elevation of intraocular pressure (IOP) has long been a vexing concern for clinicians, yet the underlying mechanisms remain inconclusive. Much of the discussion focuses on the extracellular matrix (ECM) of trabecular meshwork (TM). It is widely agreed that glucocorticoids impact the expression of matrix metalloproteinases (MMPs), leading to ECM deposition. Since Zn2+ is vital for MMPs, we explored its role in ECM alterations induced by dexamethasone (DEX). Our study revealed that in human TM cells treated with DEX, the level of intracellular Zn2+ significantly decreased, accompanied by impaired extracellular Zn2+ uptake. This correlated with changes in several Zrt-, Irt-related proteins (ZIPs) and metallothionein. ZIP8 knockdown impaired extracellular Zn2+ uptake, but Zn2+ chelation did not affect ZIP8 expression. Resembling DEX's effects, chelation of Zn2+ decreased MMP2 expression, increased the deposition of ECM proteins, and induced structural disarray of ECM. Conversely, supplementation of exogenous Zn2+ in DEX-treated cells ameliorated these outcomes. Notably, dietary zinc supplementation in mice significantly reduced DEX-induced IOP elevation and collagen content in TM, thereby rescuing the visual function of the mice. These findings underscore zinc's pivotal role in ECM regulation, providing a novel perspective on the pathogenesis of glaucoma.NEW & NOTEWORTHY Our study explores zinc's pivotal role in mitigating extracellular matrix dysregulation in the trabecular meshwork and glucocorticoid-induced ocular hypertension. We found that in human trabecular meshwork cells treated with dexamethasone, intracellular Zn2+ significantly decreased, accompanied by impaired extracellular Zn2+ uptake. Zinc supplementation rescues visual function by modulating extracellular matrix proteins and lowering intraocular pressure, offering a direction for further exploration in glaucoma management.
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Affiliation(s)
- Canying Liu
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
| | - Jiahui Tang
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
| | - Yuze Chen
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
| | - Qi Zhang
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
| | - Jicheng Lin
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
| | - Siting Wu
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
| | - Jiaxu Han
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
| | - Zhe Liu
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
| | - Caiqing Wu
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
| | - Yehong Zhuo
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
| | - Yiqing Li
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceGuangzhouChina
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Baratta RO, Schlumpf E, Del Buono BJ, DeLorey S, Ousler G, Calkins DJ. A Phase 2 Trial to Test Safety and Efficacy of ST-100, a Unique Collagen Mimetic Peptide Ophthalmic Solution for Dry Eye Disease. Ophthalmol Sci 2024; 4:100451. [PMID: 38317866 PMCID: PMC10838901 DOI: 10.1016/j.xops.2023.100451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 12/03/2023] [Accepted: 12/07/2023] [Indexed: 02/07/2024]
Abstract
Objective Dry eye disease (DED) is a worldwide source of ocular discomfort. This first-in-human phase 2 clinical study determined the efficacy of treating signs and symptoms of DED using an ophthalmic solution of synthesized mimetic of human collagen (ST-100). Design This double-masked, randomized, study compared high (60 μg/mL) and low (22 μg/mL) dose ST-100 to vehicle utilizing the Ora, Inc. Controlled Adverse Environment (CAE) during a 28-day period. Participants Participants included males and females ≥ 18 years of age with signs and symptoms of DED for ≥ 6 months that worsened during CAE exposure who were not taking any topical prescription therapeutic. Intervention Participants applied ST-100 or vehicle placebo topically to both corneas (1 drop) twice daily via a blow-fill-sealed preservative-free container. Main Outcome Measures The prespecified primary efficacy sign end point was mean change from baseline (CFB) in total corneal fluorescein staining, and the primary symptom end point was mean CFB in ocular discomfort. A secondary prespecified efficacy end point was CFB in unanesthetized Schirmer's test for tear film production. Results Of 160 subjects in the intent-to-treat population (112 female, 48 male, median age 64), 146 completed the study. Total corneal fluorescein staining CFB improved for high-dose ST-100, with superiority over vehicle when both eyes were considered together (2-sample t test: P = 0.0394). High-dose ST-100 was superior to vehicle in Schirmer's CFB for the study eye (least squares mean difference [confidence interval] = 2.3 [0.6, 4.0], P = 0.0094). For study eyes, the proportion of Schirmer's test responders (CFB ≥ 10 mm, Schirmer's responder rate) was 12.2% for high-dose ST-100 versus 0.0% for vehicle (P = 0.0266). The CFB for ocular discomfort score improved in study eyes for high- and low-dose ST-100 (paired t test, P = 0.0133, P = 0.0151, respectively) but without superiority over vehicle (ANCOVA: P = 0.5696, P = 0.8968, respectively). ST-100 Schirmer's responders also demonstrated total elimination of worsening of corneal fluorescein stain during the stress of CAE sessions. Conclusions ST-100 significantly improved tear production and related outcomes in DED and was well-tolerated in reducing symptoms. Financial Disclosures Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
| | | | | | | | | | - David J. Calkins
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee
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Wareham LK, Baratta RO, Del Buono BJ, Schlumpf E, Calkins DJ. Collagen in the central nervous system: contributions to neurodegeneration and promise as a therapeutic target. Mol Neurodegener 2024; 19:11. [PMID: 38273335 PMCID: PMC10809576 DOI: 10.1186/s13024-024-00704-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 01/10/2024] [Indexed: 01/27/2024] Open
Abstract
The extracellular matrix is a richly bioactive composition of substrates that provides biophysical stability, facilitates intercellular signaling, and both reflects and governs the physiological status of the local microenvironment. The matrix in the central nervous system (CNS) is far from simply an inert scaffold for mechanical support, instead conducting an active role in homeostasis and providing broad capacity for adaptation and remodeling in response to stress that otherwise would challenge equilibrium between neuronal, glial, and vascular elements. A major constituent is collagen, whose characteristic triple helical structure renders mechanical and biochemical stability to enable bidirectional crosstalk between matrix and resident cells. Multiple members of the collagen superfamily are critical to neuronal maturation and circuit formation, axon guidance, and synaptogenesis in the brain. In mature tissue, collagen interacts with other fibrous proteins and glycoproteins to sustain a three-dimensional medium through which complex networks of cells can communicate. While critical for matrix scaffolding, collagen in the CNS is also highly dynamic, with multiple binding sites for partnering matrix proteins, cell-surface receptors, and other ligands. These interactions are emerging as critical mediators of CNS disease and injury, particularly regarding changes in matrix stiffness, astrocyte recruitment and reactivity, and pro-inflammatory signaling in local microenvironments. Changes in the structure and/or deposition of collagen impact cellular signaling and tissue biomechanics in the brain, which in turn can alter cellular responses including antigenicity, angiogenesis, gliosis, and recruitment of immune-related cells. These factors, each involving matrix collagen, contribute to the limited capacity for regeneration of CNS tissue. Emerging therapeutics that attempt to rebuild the matrix using peptide fragments, including collagen-enriched scaffolds and mimetics, hold great potential to promote neural repair and regeneration. Recent evidence from our group and others indicates that repairing protease-degraded collagen helices with mimetic peptides helps restore CNS tissue and promote neuronal survival in a broad spectrum of degenerative conditions. Restoration likely involves bolstering matrix stiffness to reduce the potential for astrocyte reactivity and local inflammation as well as repairing inhibitory binding sites for immune-signaling ligands. Facilitating repair rather than endogenous replacement of collagen degraded by disease or injury may represent the next frontier in developing therapies based on protection, repair, and regeneration of neurons in the central nervous system.
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Affiliation(s)
- Lauren K Wareham
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute , Vanderbilt University Medical Center, 1161 21st Avenue S, 37232, Nashville, TN, USA
| | - Robert O Baratta
- Stuart Therapeutics, Inc., 411 SE Osceola St, 34994, Stuart, FL, USA
| | - Brian J Del Buono
- Stuart Therapeutics, Inc., 411 SE Osceola St, 34994, Stuart, FL, USA
| | - Eric Schlumpf
- Stuart Therapeutics, Inc., 411 SE Osceola St, 34994, Stuart, FL, USA
| | - David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute , Vanderbilt University Medical Center, 1161 21st Avenue S, 37232, Nashville, TN, USA
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Zhang R, Li B, Li H. Extracellular-Matrix Mechanics Regulate the Ocular Physiological and Pathological Activities. J Ophthalmol 2023; 2023:7626920. [PMID: 37521908 PMCID: PMC10386902 DOI: 10.1155/2023/7626920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 07/06/2023] [Accepted: 07/13/2023] [Indexed: 08/01/2023] Open
Abstract
The extracellular matrix (ECM) is a noncellular structure that plays an indispensable role in a series of cell life activities. Accumulating studies have demonstrated that ECM stiffness, a type of mechanical forces, exerts a pivotal influence on regulating organogenesis, tissue homeostasis, and the occurrence and development of miscellaneous diseases. Nevertheless, the role of ECM stiffness in ophthalmology is rarely discussed. In this review, we focus on describing the important role of ECM stiffness and its composition in multiple ocular structures (including cornea, retina, optic nerve, trabecular reticulum, and vitreous) from a new perspective. The abnormal changes in ECM can trigger physiological and pathological activities of the eye, suggesting that compared with different biochemical factors, the transmission and transduction of force signals triggered by mechanical cues such as ECM stiffness are also universal in different ocular cells. We expect that targeting ECM as a therapeutic approach or designing advanced ECM-based technologies will have a broader application prospect in ophthalmology.
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Affiliation(s)
- Ran Zhang
- Department of Ophthalmology & Optometry, North Sichuan Medical College, Nanchong 637000, Sichuan, China
- Department of Ophthalmology, Central Hospital of Suining City, Suining 629000, Sichuan, China
| | - Bo Li
- Department of Ophthalmology, Central Hospital of Suining City, Suining 629000, Sichuan, China
| | - Heng Li
- Department of Ophthalmology & Optometry, North Sichuan Medical College, Nanchong 637000, Sichuan, China
- Department of Ophthalmology, Central Hospital of Suining City, Suining 629000, Sichuan, China
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Agarwal R, Agarwal P, Iezhitsa I. Exploring the current use of animal models in glaucoma drug discovery: where are we in 2023? Expert Opin Drug Discov 2023; 18:1287-1300. [PMID: 37608634 DOI: 10.1080/17460441.2023.2246892] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/08/2023] [Indexed: 08/24/2023]
Abstract
INTRODUCTION Animal models are widely used in glaucoma-related research. Since the elevated intraocular pressure (IOP) is a major risk factor underlying the disease pathogenesis, animal models with high IOP are commonly used. However, models are also used to represent the clinical context of glaucomatous changes developing despite a normal IOP. AREAS COVERED Herein, the authors discuss the various factors that contribute to the quality of studies using animal models based on the evaluation of studies published in 2022. The factors affecting the quality of studies using animal models, such as the animal species, age, and sex, are discussed, along with various methods and outcomes of studies involving different animal models of glaucoma. EXPERT OPINION Translating animal research data to clinical applications remains challenging. Our observations in this review clearly indicate that many studies lack scientific robustness not only in their experiment conduct but also in data analysis, interpretation, and presentation. In this context, ensuring the internal validity of animal studies is the first step in quality assurance. External validity, however, is more challenging, and steps should be taken to satisfy external validity at least to some extent.
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Affiliation(s)
- Renu Agarwal
- School of Medicine, International Medical University, Bukit Jalil, Malaysia
| | - Puneet Agarwal
- School of Medicine, International Medical University, Bukit Jalil, Malaysia
| | - Igor Iezhitsa
- School of Medicine, International Medical University, Bukit Jalil, Malaysia
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Wareham LK, Holden JM, Bossardet OL, Baratta RO, Del Buono BJ, Schlumpf E, Calkins DJ. Collagen mimetic peptide repair of the corneal nerve bed in a mouse model of dry eye disease. Front Neurosci 2023; 17:1148950. [PMID: 37260844 PMCID: PMC10228686 DOI: 10.3389/fnins.2023.1148950] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/21/2023] [Indexed: 06/02/2023] Open
Abstract
The intraepithelial sub-basal nerve plexus of the cornea is characterized by a central swirl of nerve processes that terminate between the apical cells of the epithelium. This plexus is a critical component of maintaining homeostatic function of the ocular surface. The cornea contains a high concentration of collagen, which is susceptible to damage in conditions such as neuropathic pain, neurotrophic keratitis, and dry eye disease. Here we tested whether topical application of a collagen mimetic peptide (CMP) is efficacious in repairing the corneal sub-basal nerve plexus in a mouse model of ocular surface desiccation. We induced corneal tear film reduction, epithelial damage, and nerve bed degradation through a combination of environmental and pharmaceutical (atropine) desiccation. Mice were subjected to desiccating air flow and bilateral topical application of 1% atropine solution (4× daily) for 2 weeks. During the latter half of this exposure, mice received topical vehicle [phosphate buffered saline (PBS)] or CMP [200 μm (Pro-Pro-Gly)7, 10 μl] once daily, 2 h prior to the first atropine treatment for that day. After euthanasia, cornea were labeled with antibodies against βIII tubulin to visualize and quantify changes to the nerve bed. For mice receiving vehicle only, the two-week desiccation regimen reduced neuronal coverage of the central sub-basal plexus and epithelial terminals compared to naïve, with some corneas demonstrating complete degeneration of nerve beds. Accordingly, both sub-basal and epithelial βIII tubulin-labeled processes demonstrated increased fragmentation, indicative of nerve disassembly. Treatment with CMP significantly reduced nerve fragmentation, expanded both sub-basal and epithelial neuronal coverage compared to vehicle controls, and improved corneal epithelium integrity, tear film production, and corneal sensitivity. Together, these results indicate that topical CMP significantly counters neurodegeneration characteristic of corneal surface desiccation. Repairing underlying collagen in conditions that damage the ocular surface could represent a novel therapeutic avenue in treating a broad spectrum of diseases or injury.
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Affiliation(s)
- Lauren K. Wareham
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Joseph M. Holden
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Olivia L. Bossardet
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
| | | | | | - Eric Schlumpf
- Stuart Therapeutics, Inc., Stuart, FL, United States
| | - David J. Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, United States
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Ribeiro M, Pasini S, Baratta RO, Del Buono BJ, Schlumpf E, Calkins DJ. Collagen Mimetic Peptides Promote Adherence and Migration of ARPE-19 Cells While Reducing Inflammatory and Oxidative Stress. Int J Mol Sci 2022; 23:7004. [PMID: 35806007 PMCID: PMC9266392 DOI: 10.3390/ijms23137004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 11/28/2022] Open
Abstract
Epithelial cells of multiple types produce and interact with the extracellular matrix to maintain structural integrity and promote healthy function within diverse endogenous tissues. Collagen is a critical component of the matrix, and challenges to collagen’s stability in aging, disease, and injury influence survival of adherent epithelial cells. The retinal pigment epithelium (RPE) is important for maintaining proper function of the light-sensitive photoreceptors in the neural retina, in part through synergy with the collagen-rich Bruch’s membrane that promotes RPE adherence. Degradation of Bruch’s is associated with RPE degeneration, which is implicated early in age-related macular degeneration, a leading cause of irreversible vision loss worldwide. Collagen mimetic peptides (CMPs) effectively repair damage to collagen helices, which are present in all collagens. Our previous work indicates that in doing so, CMPs promote survival and integrity of affected cells and tissues in models of ocular injury and disease, including wounding of corneal epithelial cells. Here, we show that CMPs increase adherence and migration of the ARPE-19 line of human RPE cells challenged by digestion of their collagen substrate. Application of CMPs also reduced both ARPE-19 secretion of pro-inflammatory cytokines (interleukins 6 and 8) and production of reactive oxygen species. Taken together, these results suggest that repairing collagen damaged by aging or other pathogenic processes in the posterior eye could improve RPE adherence and survival and, in doing so, reduce the inflammatory and oxidative stress that perpetuates the cycle of destruction at the root of age-related diseases of the outer retina.
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Murphy-Ullrich JE. Thrombospondin-1 Signaling Through the Calreticulin/LDL Receptor Related Protein 1 Axis: Functions and Possible Roles in Glaucoma. Front Cell Dev Biol 2022; 10:898772. [PMID: 35693935 PMCID: PMC9185677 DOI: 10.3389/fcell.2022.898772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
Thrombospondin-1 (TSP-1) is a matricellular extracellular matrix protein. Matricellular proteins are components of the extracellular matrix (ECM) that regulate key cellular functions and impact ECM organization, but which lack direct primary structural roles in the ECM. TSP-1 expression is upregulated in response to injury, hypoxia, growth factor stimulation, inflammation, glucose, and by reactive oxygen species. Relevant to glaucoma, TSP-1 is also a mechanosensitive molecule upregulated by mechanical stretch. TSP-1 expression is increased in ocular remodeling in glaucoma in both the trabecular meshwork and in the optic nerve head. The exact roles of TSP-1 in glaucoma remain to be defined, however. It plays important roles in cell behavior and in ECM remodeling during wound healing, fibrosis, angiogenesis, and in tumorigenesis and metastasis. At the cellular level, TSP-1 can modulate cell adhesion and migration, protease activity, growth factor activity, anoikis resistance, apoptosis, and collagen secretion and matrix assembly and cross-linking. These multiple functions and macromolecular and receptor interactions have been ascribed to specific domains of the TSP-1 molecule. In this review, we will focus on the cell regulatory activities of the TSP-1 N-terminal domain (NTD) sequence that binds to cell surface calreticulin (Calr) and which regulates cell functions via signaling through Calr complexed with LDL receptor related protein 1 (LRP1). We will describe TSP-1 actions mediated through the Calr/LRP1 complex in regulating focal adhesion disassembly and cytoskeletal reorganization, cell motility, anoikis resistance, and induction of collagen secretion and matrix deposition. Finally, we will consider the relevance of these TSP-1 functions to the pathologic remodeling of the ECM in glaucoma.
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Affiliation(s)
- Joanne E. Murphy-Ullrich
- Departments of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, United States
- *Correspondence: Joanne E. Murphy-Ullrich,
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