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Cui H, Sun D, Meng S, Ma TJ, Ye Z, Li ZH. SIRT1 inhibits apoptosis of human lens epithelial cells through suppressing endoplasmic reticulum stress in vitro and in vivo. Int J Ophthalmol 2024; 17:1205-1216. [PMID: 39026915 PMCID: PMC11246941 DOI: 10.18240/ijo.2024.07.04] [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: 03/13/2024] [Accepted: 03/28/2024] [Indexed: 07/20/2024] Open
Abstract
AIM To explore the effect of silent information regulator factor 2-related enzyme 1 (SIRT1) on modulating apoptosis of human lens epithelial cells (HLECs) and alleviating lens opacification of rats through suppressing endoplasmic reticulum (ER) stress. METHODS HLECs (SRA01/04) were treated with varying concentrations of tunicamycin (TM) for 24h, and the expression of SIRT1 and C/EBP homologous protein (CHOP) was assessed using real-time quantitative polymerase chain reaction (RT-PCR), Western blotting, and immunofluorescence. Cell morphology and proliferation was evaluated using an inverted microscope and cell counting kit-8 (CCK-8) assay, respectively. In the SRA01/04 cell apoptosis model, which underwent siRNA transfection for SIRT1 knockdown and SRT1720 treatment for its activation, the expression levels of SIRT1, CHOP, glucose regulated protein 78 (GRP78), and activating transcription factor 4 (ATF4) were examined. The potential reversal of SIRT1 knockdown effects by 4-phenyl butyric acid (4-PBA; an ER stress inhibitor) was investigated. In vivo, age-related cataract (ARC) rat models were induced by sodium selenite injection, and the protective role of SIRT1, activated by SRT1720 intraperitoneal injections, was evaluated through morphology observation, hematoxylin and eosin (H&E) staining, Western blotting, and RT-PCR. RESULTS SIRT1 expression was downregulated in TM-induced SRA01/04 cells. Besides, in SRA01/04 cells, both cell apoptosis and CHOP expression increased with the rising doses of TM. ER stress was stimulated by TM, as evidenced by the increased GRP78 and ATF4 in the SRA01/04 cell apoptosis model. Inhibition of SIRT1 by siRNA knockdown increased ER stress activation, whereas SRT1720 treatment had opposite results. 4-PBA partly reverse the adverse effect of SIRT1 knockdown on apoptosis. In vivo, SRT1720 attenuated the lens opacification and weakened the ER stress activation in ARC rat models. CONCLUSION SIRT1 plays a protective role against TM-induced apoptosis in HLECs and slows the progression of cataract in rats by inhibiting ER stress. These findings suggest a novel strategy for cataract treatment focused on targeting ER stress, highlighting the therapeutic potential of SIRT1 modulation in ARC development.
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Affiliation(s)
- Hui Cui
- Medical School of Chinese PLA, Beijing 100089, China
- Senior Department of Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing 100853, China
| | - Di Sun
- Medical School of Chinese PLA, Beijing 100089, China
- Senior Department of Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing 100853, China
| | - Sheng Meng
- Medical School of Chinese PLA, Beijing 100089, China
| | - Tian-Ju Ma
- Senior Department of Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing 100853, China
| | - Zi Ye
- Senior Department of Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing 100853, China
| | - Zhao-Hui Li
- Senior Department of Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing 100853, China
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Li Y, Zhu Y, Huang J, Ho YW, Fang JKH, Lam EY. High-throughput microplastic assessment using polarization holographic imaging. Sci Rep 2024; 14:2355. [PMID: 38287056 PMCID: PMC10824714 DOI: 10.1038/s41598-024-52762-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 01/22/2024] [Indexed: 01/31/2024] Open
Abstract
Microplastic (MP) pollution has emerged as a global environmental concern due to its ubiquity and harmful impacts on ecosystems and human health. MP assessment has therefore become increasingly necessary and common in environmental and experimental samples. Microscopy and spectroscopy are widely employed for the physical and chemical characterization of MPs. However, these analytical methods often require time-consuming pretreatments of samples or expensive instrumentation. In this work, we develop a portable and cost-effective polarization holographic imaging system that prominently incorporates deep learning techniques, enabling efficient, high-throughput detection and dynamic analysis of MPs in aqueous environments. The integration enhances the identification and classification of MPs, eliminating the need for extensive sample preparation. The system simultaneously captures holographic interference patterns and polarization states, allowing for multimodal information acquisition to facilitate rapid MP detection. The characteristics of light waves are registered, and birefringence features are leveraged to classify the material composition and structures of MPs. Furthermore, the system automates real-time counting and morphological measurements of various materials, including MP sheets and additional natural substances. This innovative approach significantly improves the dynamic monitoring of MPs and provides valuable information for their effective filtration and management.
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Affiliation(s)
- Yuxing Li
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Yanmin Zhu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Jianqing Huang
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
- Key Lab of Education Ministry for Power Machinery and Engineering, School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Yuen-Wa Ho
- Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - James Kar-Hei Fang
- Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Edmund Y Lam
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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Minogue PJ, Rodriguez SH, Berthoud VM, Beyer EC. Pediatric cataracts of different etiologies contain insoluble, calcified particles. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1213359. [PMID: 37441058 PMCID: PMC10338002 DOI: 10.3389/fopht.2023.1213359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/15/2023]
Abstract
Our recent studies in mice suggest that a crucial event for the development of cataracts is the formation of calcium-containing deposits. To examine the generality of pathologic mineralization as a novel mechanism of cataract formation, we analyzed lens material from different human cataract surgeries. Human lens material was obtained from routine cataract surgeries performed on three patients with dense, white cataracts: a 10-month-old with congenital cataracts, a 9-year-old with a uveitic cataract, and a 17-year-old with a traumatic cataract. The aspirated material from the cataract surgeries contained insoluble material that could be isolated by centrifugation. Many particles within the insoluble fraction stained with Alizarin red, a dye that stains insoluble calcified material. The appearance of these human insoluble, Alizarin red-stained particles was similar to some of those detected in homogenates from cataractous mouse lenses. These results support the hypothesis that pathologic mineralization may have a mechanistic role in the formation of cataracts of different etiologies.
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Affiliation(s)
- Peter J. Minogue
- Department of Pediatrics, University of Chicago, Chicago, IL, USA
| | - Sarah H. Rodriguez
- Department of Pediatrics, University of Chicago, Chicago, IL, USA
- Department of Ophthalmology and Visual Science, University of Chicago, Chicago, IL, USA
| | | | - Eric C. Beyer
- Department of Pediatrics, University of Chicago, Chicago, IL, USA
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Bergman MR, Deravi LF. Manipulating polydispersity of lens β-crystallins using divalent cations demonstrates evidence of calcium regulation. Proc Natl Acad Sci U S A 2022; 119:e2212051119. [PMID: 36417439 PMCID: PMC9860307 DOI: 10.1073/pnas.2212051119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/13/2022] [Indexed: 11/24/2022] Open
Abstract
Crystallins comprise the protein-rich tissue of the eye lens. Of the three most common vertebrate subtypes, β-crystallins exhibit the widest degree of polydispersity due to their complex multimerization properties in situ. While polydispersity enables precise packing densities across the concentration gradient of the lens for vision, it is unclear why there is such a high degree of structural complexity within the β-crystallin subtype and what the role of this feature is in the lens. To investigate this, we first characterized β-crystallin polydispersity and then established a method to dynamically disrupt it in a process that is dependent on isoform composition and the presence of divalent cationic salts (CaCl2 or MgCl2). We used size-exclusion chromatography together with dynamic light scattering and mass spectrometry to show how high concentrations of divalent cations dissociate β-crystallin oligomers, reduce polydispersity, and shift the overall protein surface charge-properties that can be reversed when salts are removed. While the direct, physiological relevance of these divalent cations in the lens is still under investigation, our results support that specific isoforms of β-crystallin modulate polydispersity through multiple chemical equilibria and that this native state is disrupted by cation binding. This dynamic process may be essential to facilitating the molecular packing and optical function of the lens.
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Affiliation(s)
- Michael R. Bergman
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA02115
| | - Leila F. Deravi
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA02115
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Minogue PJ, Sommer AJ, Williams JC, Bledsoe SB, Beyer EC, Berthoud VM. Connexin Mutants Cause Cataracts Through Deposition of Apatite. Front Cell Dev Biol 2022; 10:951231. [PMID: 35938173 PMCID: PMC9355134 DOI: 10.3389/fcell.2022.951231] [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: 05/23/2022] [Accepted: 06/22/2022] [Indexed: 11/13/2022] Open
Abstract
Cataracts are lens opacities that are among the most common causes of blindness. It is commonly believed that cataracts develop through the accumulation of damage to lens proteins. However, recent evidence suggests that cataracts can result from calcium ion accumulation and the precipitation of calcium-containing salts. To test for the presence of precipitates and to identify their components, we studied the lenses of mice that develop cataracts due to mutations of connexin46 and connexin50. Micro-computed tomography showed the presence of radio-dense mineral in the mutant lenses, but not in wild-type lenses. Three-dimensional reconstructions of the scans showed that the distribution of the radio-dense mineral closely paralleled the location and morphology of the cataracts. The mutant lens homogenates also contained insoluble particles that stained with Alizarin red (a dye that stains Ca2+ deposits). Using attenuated total internal reflection micro–Fourier transform infrared spectroscopy, we identified the mineral as calcium phosphate in the form of apatite. Taken together, these data support the novel paradigm that cataracts are formed through pathological mineralization within the lens.
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Affiliation(s)
- Peter J. Minogue
- Department of Pediatrics, University of Chicago, Chicago, IL, United States
| | - Andre J. Sommer
- Molecular Microspectroscopy Laboratory, Department of Chemistry and Biochemistry, Miami University, Oxford, OH, United States
| | - James C. Williams
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Sharon B. Bledsoe
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Eric C. Beyer
- Department of Pediatrics, University of Chicago, Chicago, IL, United States
| | - Viviana M. Berthoud
- Department of Pediatrics, University of Chicago, Chicago, IL, United States
- *Correspondence: Viviana M. Berthoud,
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Delamere NA, Shahidullah M. Ion Transport Regulation by TRPV4 and TRPV1 in Lens and Ciliary Epithelium. Front Physiol 2022; 12:834916. [PMID: 35173627 PMCID: PMC8841554 DOI: 10.3389/fphys.2021.834916] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 12/27/2021] [Indexed: 02/02/2023] Open
Abstract
Aside from a monolayer of epithelium at the anterior surface, the lens is formed by tightly compressed multilayers of fiber cells, most of which are highly differentiated and have a limited capacity for ion transport. Only the anterior monolayer of epithelial cells has high Na, K-ATPase activity. Because the cells are extensively coupled, the lens resembles a syncytium and sodium-potassium homeostasis of the entire structure is largely dependent on ion transport by the epithelium. Here we describe recent studies that suggest TRPV4 and TRPV1 ion channels activate signaling pathways that play an important role in matching epithelial ion transport activity with needs of the lens cell mass. A TRPV4 feedback loop senses swelling in the fiber mass and increases Na, K-ATPase activity to compensate. TRPV4 channel activation in the epithelium triggers opening of connexin hemichannels, allowing the release of ATP that stimulates purinergic receptors in the epithelium and results in the activation of Src family tyrosine kinases (SFKs) and SFK-dependent increase of Na, K-ATPase activity. A separate TRPV1 feedback loop senses shrinkage in the fiber mass and increases NKCC1 activity to compensate. TRPV1 activation causes calcium-dependent activation of a signaling cascade in the lens epithelium that involves PI3 kinase, ERK, Akt and WNK. TRPV4 and TRPV1 channels are also evident in the ciliary body where Na, K-ATPase is localized on one side of a bilayer in which two different cell types, non-pigmented and pigmented ciliary epithelium, function in a coordinated manner to secrete aqueous humor. TRPV4 and TRPV1 may have a role in maintenance of cell volume homeostasis as ions and water move through the bilayer.
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