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Ling J, Chan BCL, Tsang MSM, Gao X, Leung PC, Lam CWK, Hu JM, Wong CK. Current Advances in Mechanisms and Treatment of Dry Eye Disease: Toward Anti-inflammatory and Immunomodulatory Therapy and Traditional Chinese Medicine. Front Med (Lausanne) 2022; 8:815075. [PMID: 35111787 PMCID: PMC8801439 DOI: 10.3389/fmed.2021.815075] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/27/2021] [Indexed: 12/19/2022] Open
Abstract
Dry eye is currently one of the most common ocular surface disease. It can lead to ocular discomfort and even cause visual impairment, which greatly affects the work and quality of life of patients. With the increasing incidence of dry eye disease (DED) in recent years, the disease is receiving more and more attention, and has become one of the hot research fields in ophthalmology research. Recently, with the in-depth research on the etiology, pathogenesis and treatment of DED, it has been shown that defects in immune regulation is one of the main pathological mechanisms of DED. Since the non-specific and specific immune response of the ocular surface are jointly regulated, a variety of immune cells and inflammatory factors are involved in the development of DED. The conventional treatment of DED is the application of artificial tears for lubricating the ocular surface. However, for moderate-to-severe DED, treatment with anti-inflammatory drugs is necessary. In this review, the immunomodulatory mechanisms of DED and the latest research progress of its related treatments including Chinese medicine will be discussed.
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Affiliation(s)
- Jiawei Ling
- Institute of Chinese Medicine and State Key Laboratory of Research on Bioactivities and Clinical Applications of Medicinal Plants, The Chinese University of Hong Kong, Hong Kong, China
| | - Ben Chung-Lap Chan
- Institute of Chinese Medicine and State Key Laboratory of Research on Bioactivities and Clinical Applications of Medicinal Plants, The Chinese University of Hong Kong, Hong Kong, China
| | - Miranda Sin-Man Tsang
- Institute of Chinese Medicine and State Key Laboratory of Research on Bioactivities and Clinical Applications of Medicinal Plants, The Chinese University of Hong Kong, Hong Kong, China
- Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China
| | - Xun Gao
- Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China
| | - Ping Chung Leung
- Institute of Chinese Medicine and State Key Laboratory of Research on Bioactivities and Clinical Applications of Medicinal Plants, The Chinese University of Hong Kong, Hong Kong, China
| | - Christopher Wai-Kei Lam
- Faculty of Medicine and State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, Macau SAR, China
| | - Jiang-Miao Hu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Chun Kwok Wong
- Institute of Chinese Medicine and State Key Laboratory of Research on Bioactivities and Clinical Applications of Medicinal Plants, The Chinese University of Hong Kong, Hong Kong, China
- Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China
- Li Dak Sum Yip Yio Chin R & D Centre for Chinese Medicine, The Chinese University of Hong Kong, Hong Kong, China
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2
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Ravi R, Kumaraswamy A, Chauhan P, Subramaniam Rajesh B. Exogenous administration of hydrogen sulfide alleviates homocysteine induced inflammation in ARPE-19 cells. Exp Eye Res 2021; 212:108759. [PMID: 34499917 DOI: 10.1016/j.exer.2021.108759] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/21/2021] [Accepted: 09/01/2021] [Indexed: 02/03/2023]
Abstract
Plasma homocysteine (Hcy) is an independent risk factor for Age related macular degeneration (AMD) and an inducer of inflammation. Homocysteine catabolism releases hydrogen sulfide (H2S). H2S has controversial effects on inflammation. In this study we have analysed the endogenous and exogenous H2S in modulating inflammation using adult retinal pigment epithelial (ARPE-19) cells as an in vitro model for AMD. ARPE-19 cells were treated with various concentrations of Hcy (15, 30 and 50 μM) for 3 h. Expression of Hcy transulfuration genes (CBS, CSE) by qPCR and western blot. H2S levels were measured using Free Radical Analyzer System (WPI, USA). The inflammatory markers (IL-6 and IL-8) were evaluated using real-time PCR and ELISA. Hcy exposure increased CBS protein expression, hydrogen sulfide levels and pro-inflammatory cytokines, modulating CBS by silencing did not alter H2S levels, but inhibition of CSE with PAG inhibited H2S production and decreased cytokine (IL-6 and IL-8) levels. On the contrary exogenous supply of hydrogen sulfide with NaHS and by compound 1c showed anti-inflammatory effects even in the presence of Hcy. This study shows that exogenous delivery of H2S decreases inflammation in retinal pigment epithelial cells on exposure to Hcy in ARPE-19 cells.
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Affiliation(s)
- Ramya Ravi
- R.S. Mehta Jain Department of Biochemistry and Cell Biology, KBIRVO, Vision Research Foundation, Sankara Nethralaya, Chennai, 600006, India; School of Chemical and Biotechnology, SASTRA Deemed to Be University, Thanjavur, India
| | - Anand Kumaraswamy
- R.S. Mehta Jain Department of Biochemistry and Cell Biology, KBIRVO, Vision Research Foundation, Sankara Nethralaya, Chennai, 600006, India
| | - Preeti Chauhan
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan Pune, 411 008, Maharashtra, India
| | - Bharathidevi Subramaniam Rajesh
- R.S. Mehta Jain Department of Biochemistry and Cell Biology, KBIRVO, Vision Research Foundation, Sankara Nethralaya, Chennai, 600006, India.
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3
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George AK, Homme RP, Stanisic D, Tyagi SC, Singh M. Protecting the aging eye with hydrogen sulfide. Can J Physiol Pharmacol 2021; 99:161-170. [PMID: 32721225 DOI: 10.1139/cjpp-2020-0216] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Research demonstrates that senescence is associated with tissue and organ dysfunction, and the eye is no exception. Sequelae arising from aging have been well defined as distinct clinical entities and vision impairment has significant psychosocial consequences. Retina and adjacent tissues like retinal pigmented epithelium and choroid are the key structures that are required for visual perception. Any structural and functional changes in retinal layers and blood retinal barrier could lead to age-related macular degeneration, diabetic retinopathy, and glaucoma. Further, there are significant oxygen gradients in the eye that can lead to excessive reactive oxygen species, resulting in endoplasmic reticulum and mitochondrial stress response. These radicals are source of functional and morphological impairment in retinal pigmented epithelium and retinal ganglion cells. Therefore, ocular diseases could be summarized as disturbance in the redox homeostasis. Hyperhomocysteinemia is a risk factor and causes vascular occlusive disease of the retina. Interestingly, hydrogen sulfide (H2S) has been proven to be an effective antioxidant agent, and it can help treat diseases by alleviating stress and inflammation. Concurrent glutamate excitotoxicity, endoplasmic reticulum stress, and microglia activation are also linked to stress; thus, H2S may offer additional interventional strategy. A refined understanding of the aging eye along with H2S biology and pharmacology may help guide newer therapies for the eye.
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Affiliation(s)
- Akash K George
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY, USA
| | - Rubens P Homme
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY, USA
| | - Dragana Stanisic
- Department of Dentistry, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Suresh C Tyagi
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, USA
| | - Mahavir Singh
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY, USA
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4
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Peng JJ, Song WT, Yao F, Zhang X, Peng J, Luo XJ, Xia XB. Involvement of regulated necrosis in blinding diseases: Focus on necroptosis and ferroptosis. Exp Eye Res 2020; 191:107922. [PMID: 31923413 DOI: 10.1016/j.exer.2020.107922] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/17/2019] [Accepted: 01/05/2020] [Indexed: 12/15/2022]
Abstract
Besides apoptosis, necrosis can also occur in a highly regulated and genetically controlled manner, defined as regulated necrosis, which is characterized by a loss of cell membrane integrity and release of cytoplasmic content. Depending on the involvement of its signal pathway, regulated necrosis can be further classified as necroptosis, ferroptosis, pyroptosis and parthanatos. Numerous studies have demonstrated that regulated necrosis is involved in the pathogenesis of many diseases covering almost all organs including the brain, heart, liver, kidney, intestine, blood vessel, eye and skin, particularly myocardial infarction and stroke. Most recently, growing evidence suggests that multiple types of regulated necrosis contribute to the degeneration of retinal ganglion cells, retinal pigment epithelial cells or photoreceptor cells, which are the main pathologic features for glaucoma, age-related macular degeneration or retinitis pigmentosa, respectively. This review focuses on the involvement of necroptosis and ferroptosis in these blinding diseases.
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Affiliation(s)
- Jing-Jie Peng
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, 410008, China; Department of Laboratory Medicine, The Third Xiangya Hospital of Central South University, Changsha, 410013, China
| | - Wei-Tao Song
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Fei Yao
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Xuan Zhang
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Jun Peng
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China
| | - Xiu-Ju Luo
- Department of Laboratory Medicine, The Third Xiangya Hospital of Central South University, Changsha, 410013, China.
| | - Xiao-Bo Xia
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, 410008, China.
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5
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Kar S, Shahshahan HR, Kambis TN, Yadav SK, Li Z, Lefer DJ, Mishra PK. Hydrogen Sulfide Ameliorates Homocysteine-Induced Cardiac Remodeling and Dysfunction. Front Physiol 2019; 10:598. [PMID: 31178749 PMCID: PMC6544124 DOI: 10.3389/fphys.2019.00598] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 04/26/2019] [Indexed: 12/13/2022] Open
Abstract
Patients with diabetes, a methionine-rich meat diet, or certain genetic polymorphisms show elevated levels of homocysteine (Hcy), which is strongly associated with the development of cardiovascular disease including diabetic cardiomyopathy. However, reducing Hcy levels with folate shows no beneficial cardiac effects. We have previously shown that a hydrogen sulfide (H2S), a by-product of Hcy through transsulfuration by cystathionine beta synthase (CBS), donor mitigates Hcy-induced hypertrophy in cardiomyocytes. However, the in vivo cardiac effects of H2S in the context of hyperhomocysteinemia (HHcy) have not been studied. We tested the hypothesis that HHcy causes cardiac remodeling and dysfunction in vivo, which is ameliorated by H2S. Twelve-week-old male CBS+/− (a model of HHcy) and sibling CBS+/+ (WT) mice were treated with SG1002 (a slow release H2S donor) diet for 4 months. The left ventricle of CBS+/− mice showed increased expression of early remodeling signals c-Jun and c-Fos, increased interstitial collagen deposition, and increased cellular hypertrophy. Notably, SG1002 treatment slightly reduced c-Jun and c-Fos expression, decreased interstitial fibrosis, and reduced cellular hypertrophy. Pressure volume loop analyses in CBS+/− mice revealed increased end systolic pressure with no change in stroke volume (SV) suggesting increased afterload, which was abolished by SG1002 treatment. Additionally, SG1002 treatment increased end-diastolic volume and SV in CBS+/− mice, suggesting increased ventricular filling. These results demonstrate SG1002 treatment alleviates cardiac remodeling and afterload in HHcy mice. H2S may be cardioprotective in conditions where H2S is reduced and Hcy is elevated.
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Affiliation(s)
- Sumit Kar
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Hamid R Shahshahan
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Tyler N Kambis
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Santosh K Yadav
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Zhen Li
- Department of Pharmacology and Experimental Therapeutics, Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - David J Lefer
- Department of Pharmacology and Experimental Therapeutics, Cardiovascular Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Paras K Mishra
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE, United States
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6
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George AK, Homme RP, Majumder A, Laha A, Metreveli N, Sandhu HS, Tyagi SC, Singh M. Hydrogen sulfide intervention in cystathionine-β-synthase mutant mouse helps restore ocular homeostasis. Int J Ophthalmol 2019; 12:754-764. [PMID: 31131233 DOI: 10.18240/ijo.2019.05.09] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 02/24/2019] [Indexed: 02/03/2023] Open
Abstract
AIM To investigate the applications of hydrogen sulfide (H2S) in eye-specific ailments in mice. METHODS Heterozygous cystathionine-β-synthase (CBS+/-) and wild-type C57BL/6J (WT) mice fed with or without high methionine diet (HMD) were administered either phosphate buffered saline (PBS) or the slow-release H2S donor: GYY4137. Several analyses were performed to study GYY4137 effects by examining retinal lysates for key protein expressions along with plasma glutamate and glutathione estimations. Intraocular pressure (IOP) was monitored during GYY4137 treatment; barium sulfate and bovine serum albumin conjugated fluorescein isothiocyanate (BSA-FITC) angiographies were performed for examining vasculature and its permeability post-treatment. Vision-guided behavior was also tested employing novel object recognition test (NORT) and light-dark box test (LDBT) recordings. RESULTS CBS deficiency (CBS+/-) coupled with HMD led disruption of methionine/homocysteine (Hcy) metabolism leading to hyperhomocysteinemia (HHcy) in CBS+/- mice as reflected by increased Hcy, and s-adenosylhomocysteine hydrolase (SAHH) levels. Unlike CBS, cystathionine-γ lyase (CSE), methylenetetrahydrofolate reductase (MTHFR) levels which were reduced but compensated by GYY4137 intervention. Heightened oxidative and endoplasmic reticulum (ER) stress responses were mitigated by GYY4137 effects along with enhanced glutathione (GSH) levels. Increased glutamate levels in CBS+/- strain were prominent than WT mice and these mice also exhibited higher IOP that was lowered by GYY4137 treatment. CBS deficiency also resulted in vision-guided behavioral impairment as revealed by NORT and LDBT findings. Interestingly, GYY4137 was able to improve CBS+/- mice behavior together with lowering their glutamate levels. Blood-retinal barrier (BRB) appeared compromised in CBS+/- with vessels' leakage that was mitigated in GYY4137 treated group. This corroborated the results for occludin (an integral plasma membrane protein of the cellular tight junctions) stabilization. CONCLUSION Findings reveal that HHcy-induced glutamate excitotoxicity, oxidative damage, ER-stress and vascular permeability alone or together can compromise ocular health and that GYY4137 could serve as a potential therapeutic agent for treating HHcy induced ocular disorders.
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Affiliation(s)
- Akash K George
- Eye and Vision Science Laboratory, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.,Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Rubens P Homme
- Eye and Vision Science Laboratory, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.,Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Avisek Majumder
- Department of Medicine, UCSF Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94158, USA
| | - Anwesha Laha
- Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Naira Metreveli
- Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Harpal S Sandhu
- Department of Ophthalmology and Visual Sciences; Kentucky Lions Eye Center, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Suresh C Tyagi
- Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Mahavir Singh
- Eye and Vision Science Laboratory, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.,Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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7
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Majumder A, Singh M, George AK, Homme RP, Laha A, Tyagi SC. Remote ischemic conditioning as a cytoprotective strategy in vasculopathies during hyperhomocysteinemia: An emerging research perspective. J Cell Biochem 2018; 120:77-92. [PMID: 30272816 DOI: 10.1002/jcb.27603] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 08/07/2018] [Indexed: 12/29/2022]
Abstract
Higher levels of nonprotein amino acid homocysteine (Hcy), that is, hyperhomocysteinemia (HHcy) (~5% of general population) has been associated with severe vasculopathies in different organs; however, precise molecular mechanism(s) as to how HHcy plays havoc with body's vascular networks are largely unknown. Interventional modalities have not proven beneficial to counter multifactorial HHcy's effects on the vascular system. An ancient Indian form of exercise called 'yoga' causes transient ischemia as a result of various body postures however the cellular mechanisms are not clear. We discuss a novel perspective wherein we argue that application of remote ischemic conditioning (RIC) could, in fact, deliver anticipated results to patients who are suffering from chronic vascular dysfunction due to HHcy. RIC is the mechanistic phenomenon whereby brief episodes of ischemia-reperfusion events are applied to distant tissues/organs; that could potentially offer a powerful tool in mitigating chronic lethal ischemia in target organs during HHcy condition via simultaneous reduction of inflammation, oxidative and endoplasmic reticulum stress, extracellular matrix remodeling, fibrosis, and angiogenesis. We opine that during ischemic conditioning our organs cross talk by releasing cellular messengers in the form of exosomes containing messenger RNAs, circular RNAs, anti-pyroptotic factors, protective cytokines like musclin, transcription factors, small molecules, anti-inflammatory, antiapoptotic factors, antioxidants, and vasoactive gases. All these could help mobilize the bone marrow-derived stem cells (having tissue healing properties) to target organs. In that context, we argue that RIC could certainly play a savior's role in an unfortunate ischemic or adverse event in people who have higher levels of the circulating Hcy in their systems.
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Affiliation(s)
- Avisek Majumder
- Department of Physiology, School of Medicine, University of Louisville, Louisville, Kentucky.,Department of Biochemistry and Molecular Genetics, School of Medicine, University of Louisville, Louisville, Kentucky
| | - Mahavir Singh
- Department of Physiology, School of Medicine, University of Louisville, Louisville, Kentucky.,Eye and Vision Science Laboratory, University of Louisville, Louisville, Kentucky
| | - Akash K George
- Department of Physiology, School of Medicine, University of Louisville, Louisville, Kentucky.,Eye and Vision Science Laboratory, University of Louisville, Louisville, Kentucky
| | - Rubens Petit Homme
- Department of Physiology, School of Medicine, University of Louisville, Louisville, Kentucky.,Eye and Vision Science Laboratory, University of Louisville, Louisville, Kentucky
| | - Anwesha Laha
- Department of Physiology, School of Medicine, University of Louisville, Louisville, Kentucky
| | - Suresh C Tyagi
- Department of Physiology, School of Medicine, University of Louisville, Louisville, Kentucky
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Homme RP, Singh M, Majumder A, George AK, Nair K, Sandhu HS, Tyagi N, Lominadze D, Tyagi SC. Remodeling of Retinal Architecture in Diabetic Retinopathy: Disruption of Ocular Physiology and Visual Functions by Inflammatory Gene Products and Pyroptosis. Front Physiol 2018; 9:1268. [PMID: 30233418 PMCID: PMC6134046 DOI: 10.3389/fphys.2018.01268] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 08/21/2018] [Indexed: 02/06/2023] Open
Abstract
Diabetic patients suffer from a host of physiological abnormalities beyond just those of glucose metabolism. These abnormalities often lead to systemic inflammation via modulation of several inflammation-related genes, their respective gene products, homocysteine metabolism, and pyroptosis. The very nature of this homeostatic disruption re-sets the overall physiology of diabetics via upregulation of immune responses, enhanced retinal neovascularization, upregulation of epigenetic events, and disturbances in cells' redox regulatory system. This altered pathophysiological milieu can lead to the development of diabetic retinopathy (DR), a debilitating vision-threatening eye condition with microvascular complications. DR is the most prevalent cause of irreversible blindness in the working-age adults throughout the world as it can lead to severe structural and functional remodeling of the retina, decreasing vision and thus diminishing the quality of life. In this manuscript, we attempt to summarize recent developments and new insights to explore the very nature of this intertwined crosstalk between components of the immune system and their metabolic orchestrations to elucidate the pathophysiology of DR. Understanding the multifaceted nature of the cellular and molecular factors that are involved in DR could reveal new targets for effective diagnostics, therapeutics, prognostics, preventive tools, and finally strategies to combat the development and progression of DR in susceptible subjects.
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Affiliation(s)
- Rubens P. Homme
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
| | - Mahavir Singh
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
| | - Avisek Majumder
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, United States
| | - Akash K. George
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
| | - Kavya Nair
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
| | - Harpal S. Sandhu
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY, United States
- Kentucky Lions Eye Center, University of Louisville School of Medicine, Louisville, KY, United States
| | - Neetu Tyagi
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
| | - David Lominadze
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
| | - Suresh C Tyagi
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, United States
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Singh M, George AK, Homme RP, Majumder A, Laha A, Sandhu HS, Tyagi SC. Circular RNAs profiling in the cystathionine-β-synthase mutant mouse reveals novel gene targets for hyperhomocysteinemia induced ocular disorders. Exp Eye Res 2018; 174:80-92. [PMID: 29803556 DOI: 10.1016/j.exer.2018.05.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/09/2018] [Accepted: 05/23/2018] [Indexed: 12/15/2022]
Abstract
Cystathionine-β-synthase (CBS) gene encodes L-serine hydrolyase which catalyzes β-reaction to condense serine with homocysteine (Hcy) by pyridoxal-5'-phosphate helps to form cystathionine which in turn is converted to cysteine. CBS resides at the intersection of transmethylation, transsulfuration, and remethylation pathways, thus lack of CBS fundamentally blocks Hcy degradation; an essential step in glutathione synthesis. Redox homeostasis, free-radical detoxification and one-carbon metabolism (Methionine-Hcy-Folate cycle) require CBS and its deficiency leads to hyperhomocysteinemia (HHcy) causing retinovascular thromboembolism and eye-lens dislocation along with vascular cognitive impairment and dementia. HHcy results in retinovascular, coronary, cerebral and peripheral vessels' dysfunction and how it causes metabolic dysregulation predisposing patients to serious eye conditions remains unknown. HHcy orchestrates inflammation and redox imbalance via epigenetic remodeling leading to neurovascular pathologies. Although circular RNAs (circRNAs) are dominant players regulating their parental genes' expression dynamics, their importance in ocular biology has not been appreciated. Progress in gene-centered analytics via improved microarray and bioinformatics are enabling dissection of genomic pathways however there is an acute under-representation of circular RNAs in ocular disorders. This study undertook circRNAs' analysis in the eyes of CBS deficient mice identifying a pool of 12532 circRNAs, 74 exhibited differential expression profile, ∼27% were down-regulated while most were up-regulated (∼73%). Findings also revealed several microRNAs that are specific to each circRNA suggesting their roles in HHcy induced ocular disorders. Further analysis of circRNAs helped identify novel parental genes that seem to influence certain eye disease phenotypes.
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Affiliation(s)
- Mahavir Singh
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA.
| | - Akash K George
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Rubens Petit Homme
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Avisek Majumder
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Anwesha Laha
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Harpal S Sandhu
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY 40202, USA; Kentucky Lions Eye Center, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Suresh C Tyagi
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
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10
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Laha A, Majumder A, Singh M, Tyagi SC. Connecting homocysteine and obesity through pyroptosis, gut microbiome, epigenetics, peroxisome proliferator-activated receptor γ, and zinc finger protein 407. Can J Physiol Pharmacol 2018; 96:971-976. [PMID: 29890083 DOI: 10.1139/cjpp-2018-0037] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although homocysteine (Hcy), a part of the epigenome, contributes to cell death by pyroptosis and decreases peroxisome proliferator-activated receptor γ (PPARγ) levels, the mechanisms are unclear. Hcy is found in high concentrations in the sera of obese individuals, which can elicit an immune response as well by hypermethylating CpG islands of specific gene promoters, a marker of epigenetics. Hcy has also been established to chelate divalent metal ions like Cu2+ and Zn2+, but this role of Hcy has not been established in relationship with obesity. It has been known for a while that PPARγ dysregulation results in various metabolic disorders including glucose and lipid metabolism. Recently, zinc finger protein 407 (Zfp407) is reported to regulate PPARγ target gene expression without affecting PPARγ transcript and protein levels by synergistically working with PPARγ. However, the mechanism(s) of this synergy, as well as other factors contributing to or inhibiting this synergism, have not been proven. This review suggests that Hcy contributes to pyroptosis, changes gut microbiome, and alters PPARγ-dependent mechanism(s) via Zfp407-mediated upregulated adipogenesis and misbalanced fatty acid metabolism, which can predispose to obesity and, consequently, obesity-related metabolic disorders.
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Affiliation(s)
- Anwesha Laha
- Department of Physiology, University of Louisville, Louisville, KY 40202, USA.,Department of Physiology, University of Louisville, Louisville, KY 40202, USA
| | - Avisek Majumder
- Department of Physiology, University of Louisville, Louisville, KY 40202, USA.,Department of Physiology, University of Louisville, Louisville, KY 40202, USA
| | - Mahavir Singh
- Department of Physiology, University of Louisville, Louisville, KY 40202, USA.,Department of Physiology, University of Louisville, Louisville, KY 40202, USA
| | - Suresh C Tyagi
- Department of Physiology, University of Louisville, Louisville, KY 40202, USA.,Department of Physiology, University of Louisville, Louisville, KY 40202, USA
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George AK, Singh M, Homme RP, Majumder A, Sandhu HS, Tyagi SC. A hypothesis for treating inflammation and oxidative stress with hydrogen sulfide during age-related macular degeneration. Int J Ophthalmol 2018; 11:881-887. [PMID: 29862191 DOI: 10.18240/ijo.2018.05.26] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 03/12/2018] [Indexed: 12/20/2022] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness and is becoming a global crisis since affected people will increase to 288 million by 2040. Genetics, age, diabetes, gender, obesity, hypertension, race, hyperopia, iris-color, smoking, sun-light and pyroptosis have varying roles in AMD, but oxidative stress-induced inflammation remains a significant driver of pathobiology. Eye is a unique organ as it contains a remarkable oxygen-gradient that generates reactive oxygen species (ROS) which upregulates inflammatory pathways. ROS becomes a source of functional and morphological impairments in retinal pigment epithelium (RPE), endothelial cells and retinal ganglion cells. Reports demonstrated that hydrogen sulfide (H2S) acts as a signaling molecule and that it may treat ailments. Therefore, we propose a novel hypothesis that H2S may restore homeostasis in the eyes thereby reducing damage caused by oxidative injury and inflammation. Since H2S has been shown to be a powerful antioxidant because of its free-radicals' inhibition properties in addition to its beneficial effects in age-related conditions, therefore, patients may benefit from H2S salubrious effects not only by minimizing their oxidant and inflammatory injuries to retina but also by lowering retinal glutamate excitotoxicity.
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Affiliation(s)
- Akash K George
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.,Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Mahavir Singh
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.,Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Rubens Petit Homme
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.,Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Avisek Majumder
- Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.,Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Harpal S Sandhu
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.,Kentucky Lions Eye Center, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Suresh C Tyagi
- Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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