1
|
Barathi VA, Katz A, Chaudhary S, Li HL, Tal DM, Marcovich A, Do CW, Karlish SJD. A digoxin derivative that potently reduces intraocular pressure: efficacy and mechanism of action in different animal models. Am J Physiol Cell Physiol 2024; 326:C1505-C1519. [PMID: 38557355 DOI: 10.1152/ajpcell.00617.2023] [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: 11/15/2023] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/04/2024]
Abstract
Glaucoma is a blinding disease. Reduction of intraocular pressure (IOP) is the mainstay of treatment, but current drugs show side effects or become progressively ineffective, highlighting the need for novel compounds. We have synthesized a family of perhydro-1,4-oxazepine derivatives of digoxin, the selective inhibitor of Na,K-ATPase. The cyclobutyl derivative (DcB) displays strong selectivity for the human α2 isoform and potently reduces IOP in rabbits. These observations appeared consistent with a hypothesis that in ciliary epithelium DcB inhibits the α2 isoform of Na,K-ATPase, which is expressed strongly in nonpigmented cells, reducing aqueous humor (AH) inflow. This paper extends assessment of efficacy and mechanism of action of DcB using an ocular hypertensive nonhuman primate model (OHT-NHP) (Macaca fascicularis). In OHT-NHP, DcB potently lowers IOP, in both acute (24 h) and extended (7-10 days) settings, accompanied by increased aqueous humor flow rate (AFR). By contrast, ocular normotensive animals (ONT-NHP) are poorly responsive to DcB, if at all. The mechanism of action of DcB has been analyzed using isolated porcine ciliary epithelium and perfused enucleated eyes to study AH inflow and AH outflow facility, respectively. 1) DcB significantly stimulates AH inflow although prior addition of 8-Br-cAMP, which raises AH inflow, precludes additional effects of DcB. 2) DcB significantly increases AH outflow facility via the trabecular meshwork (TM). Taken together, the data indicate that the original hypothesis on the mechanism of action must be revised. In the OHT-NHP, and presumably other species, DcB lowers IOP by increasing AH outflow facility rather than by decreasing AH inflow.NEW & NOTEWORTHY When applied topically, a cyclobutyl derivative of digoxin (DcB) potently reduces intraocular pressure in an ocular hypertensive nonhuman primate model (Macaca fascicularis), associated with increased aqueous humor (AH) flow rate (AFR). The mechanism of action of DcB involves increased AH outflow facility as detected in enucleated perfused porcine eyes and, in parallel, increased (AH) inflow as detected in isolated porcine ciliary epithelium. DcB might have potential as a drug for the treatment of open-angle human glaucoma.
Collapse
Affiliation(s)
- Veluchamy Amutha Barathi
- Translational Pre-Clinical Model Platform, Singapore Institute of Eye Research (SERI)
- ACP in Ophthalmology & Visual Sciences, DUKE-NUS Graduate Medical School, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Adriana Katz
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Shashikant Chaudhary
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, People's Republic of China
| | - Hoi-Lam Li
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, People's Republic of China
| | - Daniel M Tal
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Arie Marcovich
- Opthalmology Department, Kaplan Medical Center, Rehovot, Israel
- Hebrew University Medical School, Jerusalem, Israel
| | - Chi-Wai Do
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, People's Republic of China
- Centre for Eye and Vision Research (CEVR), Hong Kong, People's Republic of China
- Research Institute for Smart Ageing (RISA), The Hong Kong Polytechnic University, Hong Kong, People's Republic of China
| | - Steven J D Karlish
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| |
Collapse
|
2
|
Shafiq M, Rafique M, Cui Y, Pan L, Do CW, Ho EA. An insight on ophthalmic drug delivery systems: Focus on polymeric biomaterials-based carriers. J Control Release 2023; 362:446-467. [PMID: 37640109 DOI: 10.1016/j.jconrel.2023.08.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/18/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023]
Abstract
Presently, different types of eye diseases, such as glaucoma, myopia, infection, and dry eyes are treated with topical eye drops. However, due to ocular surface barriers, eye drops require multiple administrations, which may cause several risks, thereby necessitating additional strategies. Some of the key characteristics of an ideal ocular drug delivery system are as follows: (a) good penetration into cornea, (b) high drug retention in the ocular tissues, (c) targetability to the desired regions of the eye, and (d) good bioavailability. It is worthy to note that the corneal epithelial tight junctions hinder the permeation of therapeutics through the cornea. Therefore, it is necessary to design nanocarriers that can overcome these barriers and enhance drug penetration into the inner parts of the eye. Moreover, intelligent multifunctional nanocarriers can be designed to include cavities, which may help encapsulate sufficient amount of the drug. In addition, nanocarriers can be modified with the targeting moieties. Different types of nanocarriers have been developed for ocular drug delivery applications, including emulsions, liposomes, micelles, and nanoparticles. However, these formulations may be rapidly cleared from the eye. The therapeutic use of the nanoparticles (NPs) is also hindered by the non-specific adsorption of proteins on NPs, which may limit their interaction with the cellular moieties or other targeted biological factors. Functional drug delivery systems (DDS), which can offer targeted ocular drug delivery while avoiding the non-specific protein adsorption could exhibit great potential. This could be further realized by the on-demand DDS, which can respond to the stimuli in a spatio-temporal fashion. The cell-mediated DDS offer another valuable platform for ophthalmological drug delivery.
Collapse
Affiliation(s)
- Muhammad Shafiq
- Department of Chemical Engineering, Faculty of Engineering, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Muhammad Rafique
- Key Laboratory of Bioactive Materials (Ministry of Education), State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yingkun Cui
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
| | - Li Pan
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China; First College of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210029, China
| | - Chi-Wai Do
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China; Research Institute of Smart Ageing (RISA), The Hong Kong Polytechnic University, Hong Kong, China; Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
| | - Emmanuel A Ho
- School of Pharmacy, University of Waterloo, Waterloo, Canada; Waterloo Institute for Nanotechnology, Waterloo, Canada; Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong.
| |
Collapse
|
3
|
Agarwal R, Iezhitsa I. Advances in targeting the extracellular matrix for glaucoma therapy: current updates. Expert Opin Ther Targets 2023; 27:1217-1229. [PMID: 38069479 DOI: 10.1080/14728222.2023.2293748] [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: 10/11/2023] [Accepted: 12/07/2023] [Indexed: 12/31/2023]
Abstract
INTRODUCTION Elevated intraocular pressure (IOP) is a well-recognized risk factor for development of primary open angle glaucoma (POAG), a leading cause of irreversible blindness. Ocular hypertension is associated with excessive extracellular matrix (ECM) deposition in trabecular meshwork (TM) resulting in increased aqueous outflow resistance and elevated IOP. Hence, therapeutic options targeting ECM remodeling in TM to lower IOP in glaucomatous eyes are of considerable importance. AREAS COVERED This paper discusses the complex process of ECM regulation in TM and explores promising therapeutic targets. The role of Transforming Growth Factor-β as a central player in ECM deposition in TM is discussed. We elaborate the key regulatory processes involved in its activation, release, signaling, and cross talk with other signaling pathways including Rho GTPase, Wnt, integrin, cytokines, and renin-angiotensin-aldosterone. Further, we summarize the therapeutic agents that have been explored to target ECM dysregulation in TM. EXPERT OPINION Targeting molecular pathways to reduce ECM deposition and/or enhance its degradation are of considerable significance for IOP lowering. Challenges lie in pinpointing specific targets and designing drug delivery systems to precisely interact with pathologically active/inactive signaling. Recent advances in monoclonal antibodies, fusion molecules, and vectored nanotechnology offer potential solutions.
Collapse
Affiliation(s)
- Renu Agarwal
- School of Medicine, International Medical University, Kuala Lumpur, Malaysia
| | - Igor Iezhitsa
- School of Medicine, International Medical University, Kuala Lumpur, Malaysia
| |
Collapse
|
4
|
Kurysheva NI, Kim VY, Kim VE, Pliyeva HM. [The value of lamina cribrosa in the diagnosis and treatment of glaucoma. Remodeling of lamina cribrosa collagen and approaches to its therapeutic treatment]. Vestn Oftalmol 2023; 139:121-126. [PMID: 37638582 DOI: 10.17116/oftalma2023139041121] [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] [Indexed: 08/29/2023]
Abstract
Among the first structures suffering damage with an increase in intraocular pressure (IOP) and in early stage of glaucoma are the lamina cribrosa (LC) and peripapillary sclera (ppScl). Changes in these structures occur at the molecular and cellular level. Extracellular matrix (ECM) is the basis of connective tissue, provides mechanical support for the cells, facilitates intercellular interactions and transport of chemicals, including in LC and ppScl. Mechanical stress causes remodeling and disorganization of the ECM, which leads to changes in the structure of the tissue itself, an increase in its rigidity and a decrease in elasticity. Taking into account the molecular and cellular mechanisms of damage to LC and ppScl, various researchers have developed strategies and tactics for therapeutic intervention on these structures, contributing to a decrease in ECM secretion and, as a consequence, suspension of their remodeling. These approaches may in the future form the basis for the treatment of glaucomatous optic neuropathy.
Collapse
Affiliation(s)
- N I Kurysheva
- Medical Biological University of Innovations and Continuing Education of the State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Moscow, Russia
- Burnasyan Federal Medical Biophysical Center of the Federal Medical Biological Agency, Moscow, Russia
- Academy of Postgraduate Education of the Federal Scientific and Clinical Center of the Federal Medical Biological Agency, Moscow, Russia
| | - V Yu Kim
- Medical Biological University of Innovations and Continuing Education of the State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Moscow, Russia
- Burnasyan Federal Medical Biophysical Center of the Federal Medical Biological Agency, Moscow, Russia
| | - V E Kim
- Medical Biological University of Innovations and Continuing Education of the State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Moscow, Russia
- Burnasyan Federal Medical Biophysical Center of the Federal Medical Biological Agency, Moscow, Russia
| | - H M Pliyeva
- Medical Biological University of Innovations and Continuing Education of the State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Moscow, Russia
- Burnasyan Federal Medical Biophysical Center of the Federal Medical Biological Agency, Moscow, Russia
| |
Collapse
|
5
|
Gu J, Sun Y, Song J, Zhao R, Di X, Zhang Y, Ge X, Zhang S, Gu Y, Sun X. Irradiation induces DJ-1 secretion from esophageal squamous cell carcinoma cells to accelerate metastasis of bystander cells via a TGF-β1 positive feedback loop. J Exp Clin Cancer Res 2022; 41:259. [PMID: 36008860 PMCID: PMC9413943 DOI: 10.1186/s13046-022-02471-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/20/2022] [Indexed: 12/24/2022] Open
Abstract
Background Radiation-induced bystander effect (RIBE) can promote tumor metastasis contributing to the failure of radiotherapy for esophageal squamous cell carcinoma (ESCC). Aberrant expression of DJ-1 has been identified in ESCC; however, the relationship between DJ-1 and RIBE in ESCC remains unknown. Methods We detected DJ-1 in the serum and cell supernatants by enzyme-linked immunosorbent assay (ELISA) and evaluated tumor metastasis by phenotypic experiments in vivo and in vitro. RNA-seq, mass spectrometry, western blot (WB), immunoprecipitation (IP), and dual-luciferase reporter assays were performed to explore the underlying mechanisms. Results DJ-1 was highly expressed in the serum of patients with ESCC receiving radiotherapy and was significantly overexpressed in the medium of ESCC cells receiving irradiation. DJ-1 promoted tumor metastasis via the TGF-β1 pathway. Mechanistic studies revealed that DJ-1 bound to HSC70 to promote Smad3 phosphorylation and nuclear aggregation in a protein-interaction manner, which activated the transcription of Thrombospondin-1 (TSP1). Subsequently, the activation of TGF-β1 by TSP1 re-promoted Smad3 phosphorylation and nuclear aggregation, constituting a positive feedback loop to strengthen the metastasis of ESCC cells, which was effectively blocked by LY2109761 and LSKL. Moreover, higher levels of serum DJ-1 in patients with ESCC were related to a poorer prognosis of radiotherapy. Conclusions Irradiation can induce ESCC cells secreting DJ-1. Secreted DJ-1 enters bystander cells to initiate activation of the TGF-β1 pathway via the DJ-1/HSC70/Smad3 signaling axis. The TSP1/TGF-β1/Smad3 positive feedback pathway constitutes the core pathway that promotes ESCC metastasis. DJ-1 is a useful biomarker for predicting the efficacy of radiotherapy and a potential therapeutic target for reversing RIBE in ESCC. Graphical Abstract Schematic diagram showing the underlying mechanism
that irradiation-induced secretion of DJ-1 accelerates the metastasis of
bystander ESCC cells. ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13046-022-02471-6.
Collapse
|
6
|
Strickland RG, Garner MA, Gross AK, Girkin CA. Remodeling of the Lamina Cribrosa: Mechanisms and Potential Therapeutic Approaches for Glaucoma. Int J Mol Sci 2022; 23:ijms23158068. [PMID: 35897642 PMCID: PMC9329908 DOI: 10.3390/ijms23158068] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 11/28/2022] Open
Abstract
Glaucomatous optic neuropathy is the leading cause of irreversible blindness in the world. The chronic disease is characterized by optic nerve degeneration and vision field loss. The reduction of intraocular pressure remains the only proven glaucoma treatment, but it does not prevent further neurodegeneration. There are three major classes of cells in the human optic nerve head (ONH): lamina cribrosa (LC) cells, glial cells, and scleral fibroblasts. These cells provide support for the LC which is essential to maintain healthy retinal ganglion cell (RGC) axons. All these cells demonstrate responses to glaucomatous conditions through extracellular matrix remodeling. Therefore, investigations into alternative therapies that alter the characteristic remodeling response of the ONH to enhance the survival of RGC axons are prevalent. Understanding major remodeling pathways in the ONH may be key to developing targeted therapies that reduce deleterious remodeling.
Collapse
Affiliation(s)
- Ryan G. Strickland
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (R.G.S.); (M.A.G.); (A.K.G.)
| | - Mary Anne Garner
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (R.G.S.); (M.A.G.); (A.K.G.)
| | - Alecia K. Gross
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (R.G.S.); (M.A.G.); (A.K.G.)
| | - Christopher A. Girkin
- Department of Ophthalmology and Vision Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Correspondence: ; Tel.: +1-205-325-8620
| |
Collapse
|
7
|
Li HL, Shan SW, Stamer WD, Li KK, Chan HHL, Civan MM, To CH, Lam TC, Do CW. Mechanistic Effects of Baicalein on Aqueous Humor Drainage and Intraocular Pressure. Int J Mol Sci 2022; 23:ijms23137372. [PMID: 35806375 PMCID: PMC9266486 DOI: 10.3390/ijms23137372] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 02/06/2023] Open
Abstract
Elevated intraocular pressure (IOP) is a major risk factor for glaucoma that results from impeded fluid drainage. The increase in outflow resistance is caused by trabecular meshwork (TM) cell dysfunction and excessive extracellular matrix (ECM) deposition. Baicalein (Ba) is a natural flavonoid and has been shown to regulate cell contraction, fluid secretion, and ECM remodeling in various cell types, suggesting the potential significance of regulating outflow resistance and IOP. We demonstrated that Ba significantly lowered the IOP by about 5 mmHg in living mice. Consistent with that, Ba increased the outflow facility by up to 90% in enucleated mouse eyes. The effects of Ba on cell volume regulation and contractility were examined in primary human TM (hTM) cells. We found that Ba (1–100 µM) had no effect on cell volume under iso-osmotic conditions but inhibited the regulatory volume decrease (RVD) by up to 70% under hypotonic challenge. In addition, Ba relaxed hTM cells via reduced myosin light chain (MLC) phosphorylation. Using iTRAQ-based quantitative proteomics, 47 proteins were significantly regulated in hTM cells after a 3-h Ba treatment. Ba significantly increased the expression of cathepsin B by 1.51-fold and downregulated the expression of D-dopachrome decarboxylase and pre-B-cell leukemia transcription factor-interacting protein 1 with a fold-change of 0.58 and 0.40, respectively. We suggest that a Ba-mediated increase in outflow facility is triggered by cell relaxation via MLC phosphorylation along with inhibiting RVD in hTM cells. The Ba-mediated changes in protein expression support the notion of altered ECM homeostasis, potentially contributing to a reduction of outflow resistance and thereby IOP.
Collapse
Affiliation(s)
- Hoi-lam Li
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong; (H.-l.L.); (S.W.S.); (K.-k.L.); (H.H.-l.C.); (C.-h.T.); (T.C.L.)
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
| | - Sze Wan Shan
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong; (H.-l.L.); (S.W.S.); (K.-k.L.); (H.H.-l.C.); (C.-h.T.); (T.C.L.)
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong
- Research Centre for Chinese Medicine Innovation (RCMI), The Hong Kong Polytechnic University, Hong Kong
| | - W. Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, NC 27708, USA;
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - King-kit Li
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong; (H.-l.L.); (S.W.S.); (K.-k.L.); (H.H.-l.C.); (C.-h.T.); (T.C.L.)
| | - Henry Ho-lung Chan
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong; (H.-l.L.); (S.W.S.); (K.-k.L.); (H.H.-l.C.); (C.-h.T.); (T.C.L.)
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong
- Research Centre for Chinese Medicine Innovation (RCMI), The Hong Kong Polytechnic University, Hong Kong
| | - Mortimer M. Civan
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Chi-ho To
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong; (H.-l.L.); (S.W.S.); (K.-k.L.); (H.H.-l.C.); (C.-h.T.); (T.C.L.)
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong
- Research Centre for Chinese Medicine Innovation (RCMI), The Hong Kong Polytechnic University, Hong Kong
| | - Thomas Chuen Lam
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong; (H.-l.L.); (S.W.S.); (K.-k.L.); (H.H.-l.C.); (C.-h.T.); (T.C.L.)
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong
- Research Centre for Chinese Medicine Innovation (RCMI), The Hong Kong Polytechnic University, Hong Kong
| | - Chi-wai Do
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong; (H.-l.L.); (S.W.S.); (K.-k.L.); (H.H.-l.C.); (C.-h.T.); (T.C.L.)
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong
- Research Centre for Chinese Medicine Innovation (RCMI), The Hong Kong Polytechnic University, Hong Kong
- Research Institute of Smart Ageing (RISA), The Hong Kong Polytechnic University, Hong Kong
- Correspondence:
| |
Collapse
|
8
|
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] [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.
Collapse
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,
| |
Collapse
|
9
|
Yuen JWM, Li KK, Lam TC. Preparation of Hard Tissues Like Bone or Cartilage for Shotgun Mass Spectrometry Analysis of the Proteome. Curr Protoc 2021; 1:e282. [PMID: 34679255 DOI: 10.1002/cpz1.282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Proteomic analyses of intervertebral discs (IVDs) reveal information for understanding the fundamentals of biological processes and pathogenesis but also provide insights for novel pharmaceutical development. Sensitive mass spectrometry techniques and bioinformatics have advanced the detection and identification of proteins from any sample. Due to the challenges of catastrophic sample-loss artifacts during hard-tissue extraction, however, many researchers have omitted the cartilage endplates of IVDs for protein extraction, analyzing only the cellular components of the annulus fibrosus and/or nucleus pulposus. The full proteomic picture of IVDs is compromised without extracting proteins from intact IVDs. Here, we describe a novel preparation method using snap-freeze grinding, which allows for mechanical disruption and customized chemical lysis of hard tissues such as bone or cartilage. This method replaces the time-consuming and insufficient conventional tissue homogenization methods. Sample loss and contamination could be minimized during proteolysis by using an in-solution protein digestion and desalting procedure. We demonstrate excellent proteome coverage with intact mouse IVDs by analyzing samples in a hybrid quadrupole time-of-flight tandem mass spectrometer. © 2021 Wiley Periodicals LLC.
Collapse
Affiliation(s)
- John W M Yuen
- School of Nursing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - K K Li
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Thomas C Lam
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.,Centre for Eye and Vision Research, Hong Kong Science Park, Pak Shek Kok, Hong Kong
| |
Collapse
|