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Valproic acid modulates collagen architecture in the postoperative conjunctival scar. J Mol Med (Berl) 2022; 100:947-961. [PMID: 35583819 DOI: 10.1007/s00109-021-02171-2] [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: 08/11/2021] [Revised: 11/10/2021] [Accepted: 11/29/2021] [Indexed: 10/18/2022]
Abstract
Valproic acid (VPA), widely used for the treatment of neurological disorders, has anti-fibrotic activity by reducing collagen production in the postoperative conjunctiva. In this study, we investigated the capacity of VPA to modulate the postoperative collagen architecture. Histochemical examination revealed that VPA treatment was associated with the formation of thinner collagen fibers in the postoperative days 7 and 14 scars. At the micrometer scale, measurements by quantitative multiphoton microscopy indicated that VPA reduced mean collagen fiber thickness by 1.25-fold. At the nanometer scale, collagen fibril thickness and diameter measured by transmission electron microscopy were decreased by 1.08- and 1.20-fold, respectively. Moreover, delicate filamentous structures in random aggregates or closely associated with collagen fibrils were frequently observed in VPA-treated tissue. At the molecular level, VPA reduced Col1a1 but induced Matn2, Matn3, and Matn4 in the postoperative day 7 conjunctival tissue. Elevation of matrilin protein expression induced by VPA was sustained till at least postoperative day 14. In primary conjunctival fibroblasts, Matn2 expression was resistant to both VPA and TGF-β2, Matn3 was sensitive to both VPA and TGF-β2 individually and synergistically, while Matn4 was modulable by VPA but not TGF-β2. MATN2, MATN3, and MATN4 localized in close association with COL1A1 in the postoperative conjunctiva. These data indicate that VPA has the capacity to reduce collagen fiber thickness and potentially collagen assembly, in association with matrilin upregulation. These properties suggest potential VPA application for the prevention of fibrotic progression in the postoperative conjunctiva. KEY MESSAGES: VPA reduces collagen fiber and fibril thickness in the postoperative scar. VPA disrupts collagen fiber assembly in conjunctival wound healing. VPA induces MATN2, MATN3, and MATN4 in the postoperative scar.
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Hou M, Shao Z, Zhang S, Liu X, Fan P, Jiang M, Zhao Y, Xiao R, Yuan H. Age-related visual impairments and retinal ganglion cells axonal degeneration in a mouse model harboring OPTN (E50K) mutation. Cell Death Dis 2022; 13:362. [PMID: 35436991 PMCID: PMC9016082 DOI: 10.1038/s41419-022-04836-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 04/02/2022] [Accepted: 04/05/2022] [Indexed: 11/09/2022]
Abstract
Retinal ganglion cells (RGCs) axons are the signal carriers of visual information between retina and brain. Therefore, they play one of the important roles affected in many optic neurodegenerative diseases like glaucoma. Among the genetic risks associated with glaucoma, the E50K mutation in the Optineurin (OPTN) gene are known to result in glaucoma in the absence of increased intraocular pressure (IOP), whereas the relevant pathological mechanism and neurological issues remain to be further investigated. In this study, the OPTN (E50K) mutant mouse model was established through CRISPR/Cas9-mediated genome editing, and aging-related RGCs loss and the visual dysfunction were identified. In E50K mice 16 months old, the axonal transport decreased comparing to wild-type (WT) mice at the same age. Furthermore, results of electron microscopy demonstrated significant morphological anomaly of mitochondria in RGCs axons of young E50K mice 3 months old, and these changes were aggravated with age. These indicated that the damaged mitochondria-associated dysfunction of RGCs axon should play an etiological role in glaucoma as an age-related outcome of OPTN (E50K) mutation. The findings of this study have potential implications for the targeted prevention and treatment of NTG.
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Abstract
PURPOSE In humans, loss-of-function mutations in the gene encoding Chordin-like 1 (CHRDL1) cause X-linked megalocornea (MGC1), characterized by bilateral corneal enlargement, decreased corneal thickness, and increased anterior chamber depth (ACD). We sought to determine whether Chrdl1 knockout (KO) mice would recapitulate the ocular findings found in patients with MGC1. METHODS We generated mice with a Chrdl1 KO allele and confirmed that male Chrdl1 hemizygous KO mice do not express Chrdl1 mRNA. We examined the eyes of male mice that were hemizygous for either the wild-type (WT) or KO allele and measured corneal diameter, corneal area, corneal thickness, endothelial cell density, ACD, tear volume, and intraocular pressure. We also harvested retinas and counted retinal ganglion cell numbers. Eye segregation pattern in the dorsal lateral geniculate nucleus were also compared between male Chrdl1 KO and WT mice. RESULTS Male Chrdl1 KO mice do not have larger cornea diameters than WT mice. KO mice have significantly thicker central corneas (116.5 ± 3.9 vs. 100.9 ± 4.2 μm, P = 0.013) and smaller ACD (325.7 ± 5.7 vs. 405.6 ± 6.3 μm, P < 0.001) than WT mice, which is the converse of what occurs in patients who lack CHRDL1. Retinal-thalamic projections and other ocular measurements did not significantly differ between KO and WT mice. CONCLUSIONS Male Chrdl1 KO mice do not have the same anterior chamber abnormalities seen in humans with CHRDL1 mutations. Therefore, Chrdl1 KO mice do not recapitulate the human MGC1 phenotype. Nevertheless, Chrdl1 plays a role during mouse ocular development because corneas in KO mice differ from those in WT mice.
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Chun YY, Yap ZL, Seet LF, Chan HH, Toh LZ, Chu SWL, Lee YS, Wong TT, Tan TTY. Positive-charge tuned gelatin hydrogel-siSPARC injectable for siRNA anti-scarring therapy in post glaucoma filtration surgery. Sci Rep 2021; 11:1470. [PMID: 33446775 PMCID: PMC7809290 DOI: 10.1038/s41598-020-80542-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 12/18/2020] [Indexed: 11/18/2022] Open
Abstract
Small interfering RNA (siRNA) therapy is a promising epigenetic silencing strategy. However, its widespread adoption has been severely impeded by its ineffective delivery into the cellular environment. Here, a biocompatible injectable gelatin-based hydrogel with positive-charge tuned surface charge is presented as an effective platform for siRNA protection and delivery. We demonstrate a two-step synthesis of a gelatin-tyramine (Gtn-Tyr) hydrogel with simultaneous charge tunability and crosslinking ability. We discuss how different physiochemical properties of the hydrogel interact with siSPARC (siRNA for secreted protein, acidic and rich in cysteine), and study the positive-charge tuned gelatin hydrogel as an effective delivery platform for siSPARC in anti-fibrotic treatment. Through in vitro studies using mouse tenon fibroblasts, the positive-charge tuned Gtn-Tyr hydrogel shows sustained siSPARC cellular internalization and effective SPARC silencing with excellent biocompatibility. Similarly, the same hydrogel platform delivering siSPARC in an in vivo assessment employing a rabbit model shows an effective reduction in subconjunctival scarring in post glaucoma filtration surgery, and is non-cytotoxic compared to a commonly used anti-scarring agent, mitomycin-C. Overall, the current siRNA delivery strategy involving the positive-charge tuned gelatin hydrogel shows effective delivery of gene silencing siSPARC for anti-fibrotic treatment. The current charge tunable hydrogel delivery system is simple to fabricate and highly scalable. We believe this delivery platform has strong translational potential for effective siRNA delivery and epigenetic silencing therapy.
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Affiliation(s)
- Yong Yao Chun
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Dr, Singapore, 637459, Singapore
- Ocular Imaging, Singapore Eye Research Institute, 20 College Road Discovery Tower Level 6, The Academia, Singapore, 169856, Singapore
| | - Zhu Li Yap
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, 20 College Road Discovery Tower Level 6, The Academia, Singapore, 169856, Singapore
- Glaucoma Service, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Li Fong Seet
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, 20 College Road Discovery Tower Level 6, The Academia, Singapore, 169856, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Dr, Singapore, 117597, Singapore
- Duke-NUS Medical School, 8 College Rd, Singapore, 169857, Singapore
| | - Hiok Hong Chan
- Glaucoma Service, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Li Zhen Toh
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, 20 College Road Discovery Tower Level 6, The Academia, Singapore, 169856, Singapore
| | - Stephanie W L Chu
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, 20 College Road Discovery Tower Level 6, The Academia, Singapore, 169856, Singapore
| | - Ying Shi Lee
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, 20 College Road Discovery Tower Level 6, The Academia, Singapore, 169856, Singapore
- Glaucoma Service, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Tina T Wong
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, 20 College Road Discovery Tower Level 6, The Academia, Singapore, 169856, Singapore.
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Dr, Singapore, 117597, Singapore.
- Duke-NUS Medical School, 8 College Rd, Singapore, 169857, Singapore.
- Glaucoma Service, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore.
- School of Materials Science and Engineering, Nanyang Technological University, 11 Faculty Ave, Singapore, 639977, Singapore.
| | - Timothy T Y Tan
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Dr, Singapore, 637459, Singapore.
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Seet LF, Chu SWL, Teng X, Toh LZ, Wong TT. Assessment of progressive alterations in collagen organization in the postoperative conjunctiva by multiphoton microscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:6495-6515. [PMID: 33282504 PMCID: PMC7687938 DOI: 10.1364/boe.403555] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 06/12/2023]
Abstract
Glaucoma filtration surgery (GFS) commonly fails due to excessive fibrosis. As collagen structure aberrations is implicated in adverse fibrotic progression, this study aims to uncover collagen organization alterations during postoperative scarring. Via quantitative second harmonic generation/two photon excitation multiphoton imaging, we reveal the scar development and phenotype in the mouse model of conjunctival scarring. We also show that multiphoton imaging corroborated the collagen ultrastructure anomaly characteristic of the SPARC-/- mouse postoperative conjunctiva. These data improve our understanding of postoperative conjunctival scarring and further enhance the utility of this model for the development of anti-fibrotic therapeutics for GFS.
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Affiliation(s)
- Li-Fong Seet
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Duke-NUS Medical School, Singapore
- Co-corresponding authors
| | - Stephanie W L Chu
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, Singapore
| | | | - Li Zhen Toh
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, Singapore
| | - Tina T Wong
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Duke-NUS Medical School, Singapore
- Glaucoma Service, Singapore National Eye Centre, Singapore
- Co-corresponding authors
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Wang H, Li M, Zhang Z, Xue H, Chen X, Ji Y. Physiological function of myocilin and its role in the pathogenesis of glaucoma in the trabecular meshwork (Review). Int J Mol Med 2018; 43:671-681. [PMID: 30483726 PMCID: PMC6317685 DOI: 10.3892/ijmm.2018.3992] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 11/16/2018] [Indexed: 12/26/2022] Open
Abstract
Myocilin is highly expressed in the trabecular meshwork (TM), which plays an important role in the regulation of intraocular pressure (IOP). Myocilin abnormalities may cause dysfunction of the TM, potentially leading to increased IOP. High IOP is a well‑known primary risk factor for glaucoma. Myocilin mutations are common among glaucoma patients, and they are implicated in juvenile‑onset open‑angle glaucoma (JOAG) and adult‑onset primary open‑angle glaucoma (POAG). Aggregation of aberrant mutant myocilins is closely associated with glaucoma pathogenesis. The aim of the present review was to discuss the recent findings regarding the major physiological functions of myocilin, such as intra‑ and extracellular proteolytic processes. We also aimed to discuss the risk factors associated with myocilin and the development of glaucoma, such as misfolded/mutant myocilin, imbalance of myocilin and extracellular proteins, and instability of mutant myocilin associated with temperature. Finally, we further outlined certain issues that are yet to be resolved, which may represent the basis for future studies on the role of myocilin in glaucoma.
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Affiliation(s)
- Hongwei Wang
- Department of Ophthalmology, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
| | - Mingzhe Li
- Department of Ophthalmology, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 201399, P.R. China
| | - Zhenzhen Zhang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, P.R. China
| | - Haifeng Xue
- Public Health School, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
| | - Xing Chen
- Department of Science and Education, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
| | - Yong Ji
- Department of General Surgery, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
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Baumann B, Augustin M, Lichtenegger A, Harper D, Muck M, Eugui P, Wartak A, Pircher M, Hitzenberger C. Polarization-sensitive optical coherence tomography imaging of the anterior mouse eye. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-12. [PMID: 30168301 DOI: 10.1117/1.jbo.23.8.086005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 08/14/2018] [Indexed: 05/20/2023]
Abstract
Polarization-sensitive optical coherence tomography (PS-OCT) enables noninvasive, high-resolution imaging of tissue polarization properties. In the anterior segments of human eyes, PS-OCT allows the visualization of birefringent and depolarizing structures. We present the use of PS-OCT for imaging the murine anterior eye. Using a spectral domain PS-OCT setup operating in the 840-nm regime, we performed in vivo volumetric imaging in anesthetized C57BL/6 mice. The polarization properties of murine anterior eye structures largely replicated those known from human PS-OCT imagery, suggesting that the mouse eye may also serve as a model system under polarization contrast. However, dissimilarities were found in the depolarizing structure of the iris which, as we confirmed in postmortem histological sections, were caused by anatomical differences between both species. In addition to the imaging of tissues in the anterior chamber and the iridocorneal angle, we demonstrate longitudinal PS-OCT imaging of the murine anterior segment during mydriasis as well as birefringence imaging of corneal pathology in an aged mouse.
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Affiliation(s)
| | | | | | | | - Martina Muck
- Medizinische Univ. Wien, Austria
- Allgemeines Krankenhaus der Stadt Wien, Austria
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Seet LF, Tan YF, Toh LZ, Chu SW, Lee YS, Venkatraman SS, Wong TT. Targeted therapy for the post-operative conjunctiva: SPARC silencing reduces collagen deposition. Br J Ophthalmol 2018; 102:1460-1470. [PMID: 30021812 PMCID: PMC6173823 DOI: 10.1136/bjophthalmol-2018-311937] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/22/2018] [Accepted: 05/24/2018] [Indexed: 11/03/2022]
Abstract
BACKGROUND To develop targeted antifibrotic therapy for glaucoma filtration surgery; this study determines the effectiveness of small interfering RNA (siRNA) to reduce in vivo secreted protein acidic and rich in cysteine (SPARC) expression using the mouse model of conjunctival scarring. METHODS Experimental surgery was performed as described for the mouse model of conjunctival scarring. Scrambled (siScram) or Sparc (siSparc) siRNAs, loaded on layer-by-layer (LbL) nanoparticles, were injected into the conjunctiva immediately after surgery. Expression of Sparc, Col1a1, Fn1 and Mmp14 was measured by real-time PCR and immunoblotting on days 7 and 14 postsurgery. Live imaging of the operated eyes was performed using slit lamp, anterior segment-optical coherence tomography and confocal microscopy. Tissue pathology was evaluated by histochemical and immunofluorescent analyses of operated conjunctival cryosections. Tissue apoptosis was quantitated by annexin V assay. RESULTS : siSparc, delivered via expanded LbL nanoparticles, significantly inhibited Sparc transcription in both day 7 (2.04-fold) and day 14 (1.39-fold) treated tissues. Sparc suppression on day 7 was associated with a significant reduction of Col1a1 (2.52-fold), Fn1 (2.89-fold) and Mmp14 (2.23-fold) mRNAs. At the protein level, both SPARC and collagen 1A1 (COL1A1) were significantly reduced at both time points with siSparc treatment. Nanoparticles were visualised within cell-like structures by confocal microscopy, while overt tissue response or apoptosis was not observed. CONCLUSIONS : SPARC targeted therapy effectively reduced both SPARC and collagen production in the operated mouse conjunctiva. This proof-of-concept study suggests that targeted treatment of fibrosis in glaucoma surgery is safe and feasible, with the potential to extend to a range of potential genes associated with fibrosis.
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Affiliation(s)
- Li Fong Seet
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Duke-NUS Medical School, Singapore, Singapore
| | - Yang Fei Tan
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Li Zhen Toh
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, Singapore, Singapore
| | - Stephanie Wl Chu
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, Singapore, Singapore
| | - Ying Shi Lee
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, Singapore, Singapore
| | - Subbu S Venkatraman
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, Singapore, Singapore .,School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.,NTU - Northwestern University Institute for Nanomedicine, Singapore, Singapore.,MedTech, National Heart Centre, Singapore, Singapore
| | - Tina T Wong
- Ocular Therapeutics and Drug Delivery, Singapore Eye Research Institute, Singapore, Singapore .,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Duke-NUS Medical School, Singapore, Singapore.,School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.,Glaucoma Service, Singapore National Eye Centre, Singapore, Singapore
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