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Xu J, Yang C, Zeng S, Wang X, Yang P, Qin L. Disturbance of neuron-microglia crosstalk mediated by GRP78 in Neuropsychiatric systemic lupus erythematosus mice. J Neuroinflammation 2023; 20:150. [PMID: 37365565 DOI: 10.1186/s12974-023-02832-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023] Open
Abstract
OBJECTIVES Neuropsychiatric systemic lupus erythematosus (NPSLE) is a serious phenotype of systemic lupus erythematosus (SLE). The disturbance of neuron-microglia crosstalk is recently revealed in many neuropsychiatric diseases but was not well studied in NPSLE. We found glucose regulatory protein 78 (GRP78), a marker of endoplasmic reticulum stress, was significantly increased in the cerebrospinal fluid (CSF) of our NPSLE cohort. We, therefore, investigated whether GRP78 can act as a mediator between the neuron-microglia crosstalk and is involved in the pathogenic process of NPSLE. METHODS Serum and CSF parameters were analyzed in 22 NPSLE patients and controls. Anti-DWEYS IgG was injected intravenously into mice to establish a model of NPSLE. Behavioral assessment, histopathological staining, RNA-seq analyses, and biochemical assays were performed to examine the neuro-immunological alterations in the mice. Rapamycin was intraperitoneally administered to define the therapeutic effect. RESULTS The level of GRP78 was elevated significantly in the CSF of the patients with NPSLE. An increase in GRP78 expression, accompanied by neuroinflammation and cognitive impairment, was also found in the brain tissues of the NPSLE model mice induced by anti-DWEYS IgG deposition on hippocampal neurons. In vitro experiments demonstrated that anti-DWEYS IgG could stimulate neurons to release GRP78, which activated microglia via TLR4/MyD88/NFκB pathway to produce more pro-inflammatory cytokines and promote migration and phagocytosis. Rapamycin ameliorated GRP78-inducing neuroinflammation and cognitive impairment in anti-DWEYS IgG-transferred mice. CONCLUSION GRP78 acts as a pathogenic factor in neuropsychiatric disorders via interfering neuron-microglia crosstalk. Rapamycin may be a promising therapeutic candidate for NPSLE.
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Affiliation(s)
- Jingyi Xu
- Department of Rheumatology and Immunology, The First Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Chunshu Yang
- Department of 1st Cancer Institute, The First Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Siyuan Zeng
- Department of Rheumatology and Immunology, The First Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Xuejiao Wang
- Department of Physiology, School of Life Science, China Medical University, Shenyang, Liaoning Province, 110122, People's Republic of China
| | - Pingting Yang
- Department of Rheumatology and Immunology, The First Hospital of China Medical University, Shenyang, 110001, People's Republic of China.
| | - Ling Qin
- Department of Physiology, School of Life Science, China Medical University, Shenyang, Liaoning Province, 110122, People's Republic of China.
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2
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Zhang Y, Zhao Z, Zhao X, Xie H, Zhang C, Sun X, Zhang J. HMGB2 causes photoreceptor death via down-regulating Nrf2/HO-1 and up-regulating NF-κB/NLRP3 signaling pathways in light-induced retinal degeneration model. Free Radic Biol Med 2022; 181:14-28. [PMID: 35091064 DOI: 10.1016/j.freeradbiomed.2022.01.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/09/2022] [Accepted: 01/21/2022] [Indexed: 12/15/2022]
Abstract
In the pathogenesis of retinal degenerative diseases, oxidative stress is a key driver leading to photoreceptor death and eventually vision loss. Currently, there are no effective therapies available to rescue photoreceptors in these diseases. High-mobility group box 2 (HMGB2), a pro-inflammatory factor and damage-associated molecular patterns (DAMPs), has been proven to mediate various inflammatory diseases, but its role in retinal degenerative diseases, especially in retinal inflammation and photoreceptor degeneration, still remains unknown. In this study, we assessed the localization and function of HMGB2 under oxidative stress and explored the underlying mechanisms in a mouse model of light-induced retinal damage (LIRD). The results showed that increased oxidative stress, the photoreceptors death, as well as the pyroptosis-related proteins were evidenced in mice retina after light exposure. HMGB2 protein was predominantly expressed in the outer nuclear layer (ONL), which was translocated to the cytoplasm and released after injury. The mechanistic effect of HMGB2 was studied in the 661w cell line treated with H2O2, showing that exogenous recombinant HMGB2 protein reduced the expressions of the antioxidant protein nuclear erythroid factor 2-related factor 2 (Nrf2) and its downstream target heme oxygenase-1 (HO-1), and induced NF-κB/NLRP3 signaling pathway. HMGB2 knockdown increased cell viability, up-regulated the expressions of Nrf2 and HO-1, down-regulated the expressions of pyroptosis-related proteins in H2O2-treated 661w cells; and also prevented photoreceptors loss and maintained ONL in mice model of LIRD. The present study proposed HMGB2 as a potential therapeutic target for treatment of retinal degenerative diseases.
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Affiliation(s)
- Yumeng Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, 200080, China; National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, 200080, China
| | - Zhenzhen Zhao
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, 200080, China; National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, 200080, China
| | - Xiaohuan Zhao
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, 200080, China; National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, 200080, China
| | - Hai Xie
- Tongji Eye Institute, Department of Regenerative Medicine, and Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Chaoyang Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, 200080, China; National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, 200080, China
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, 200080, China; National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, 200080, China.
| | - Jingfa Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, 200080, China; National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, 200080, China.
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3
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Mann G, Mora S, Madu G, Adegoke OAJ. Branched-chain Amino Acids: Catabolism in Skeletal Muscle and Implications for Muscle and Whole-body Metabolism. Front Physiol 2021; 12:702826. [PMID: 34354601 PMCID: PMC8329528 DOI: 10.3389/fphys.2021.702826] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/24/2021] [Indexed: 12/20/2022] Open
Abstract
Branched-chain amino acids (BCAAs) are critical for skeletal muscle and whole-body anabolism and energy homeostasis. They also serve as signaling molecules, for example, being able to activate mammalian/mechanistic target of rapamycin complex 1 (mTORC1). This has implication for macronutrient metabolism. However, elevated circulating levels of BCAAs and of their ketoacids as well as impaired catabolism of these amino acids (AAs) are implicated in the development of insulin resistance and its sequelae, including type 2 diabetes, cardiovascular disease, and of some cancers, although other studies indicate supplements of these AAs may help in the management of some chronic diseases. Here, we first reviewed the catabolism of these AAs especially in skeletal muscle as this tissue contributes the most to whole body disposal of the BCAA. We then reviewed emerging mechanisms of control of enzymes involved in regulating BCAA catabolism. Such mechanisms include regulation of their abundance by microRNA and by post translational modifications such as phosphorylation, acetylation, and ubiquitination. We also reviewed implications of impaired metabolism of BCAA for muscle and whole-body metabolism. We comment on outstanding questions in the regulation of catabolism of these AAs, including regulation of the abundance and post-transcriptional/post-translational modification of enzymes that regulate BCAA catabolism, as well the impact of circadian rhythm, age and mTORC1 on these enzymes. Answers to such questions may facilitate emergence of treatment/management options that can help patients suffering from chronic diseases linked to impaired metabolism of the BCAAs.
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Affiliation(s)
| | | | | | - Olasunkanmi A. J. Adegoke
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, ON, Canada
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4
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Retinal Inflammation, Cell Death and Inherited Retinal Dystrophies. Int J Mol Sci 2021; 22:ijms22042096. [PMID: 33672611 PMCID: PMC7924201 DOI: 10.3390/ijms22042096] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/12/2021] [Accepted: 02/18/2021] [Indexed: 12/15/2022] Open
Abstract
Inherited retinal dystrophies (IRDs) are a group of retinal disorders that cause progressive and severe loss of vision because of retinal cell death, mainly photoreceptor cells. IRDs include retinitis pigmentosa (RP), the most common IRD. IRDs present a genetic and clinical heterogeneity that makes it difficult to achieve proper treatment. The progression of IRDs is influenced, among other factors, by the activation of the immune cells (microglia, macrophages, etc.) and the release of inflammatory molecules such as chemokines and cytokines. Upregulation of tumor necrosis factor alpha (TNFα), a pro-inflammatory cytokine, is found in IRDs. This cytokine may influence photoreceptor cell death. Different cell death mechanisms are proposed, including apoptosis, necroptosis, pyroptosis, autophagy, excessive activation of calpains, or parthanatos for photoreceptor cell death. Some of these cell death mechanisms are linked to TNFα upregulation and inflammation. Therapeutic approaches that reduce retinal inflammation have emerged as useful therapies for slowing down the progression of IRDs. We focused this review on the relationship between retinal inflammation and the different cell death mechanisms involved in RP. We also reviewed the main anti-inflammatory therapies for the treatment of IRDs.
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Microfluidic and Microscale Assays to Examine Regenerative Strategies in the Neuro Retina. MICROMACHINES 2020; 11:mi11121089. [PMID: 33316971 PMCID: PMC7763644 DOI: 10.3390/mi11121089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/03/2020] [Accepted: 12/05/2020] [Indexed: 12/15/2022]
Abstract
Bioengineering systems have transformed scientific knowledge of cellular behaviors in the nervous system (NS) and pioneered innovative, regenerative therapies to treat adult neural disorders. Microscale systems with characteristic lengths of single to hundreds of microns have examined the development and specialized behaviors of numerous neuromuscular and neurosensory components of the NS. The visual system is comprised of the eye sensory organ and its connecting pathways to the visual cortex. Significant vision loss arises from dysfunction in the retina, the photosensitive tissue at the eye posterior that achieves phototransduction of light to form images in the brain. Retinal regenerative medicine has embraced microfluidic technologies to manipulate stem-like cells for transplantation therapies, where de/differentiated cells are introduced within adult tissue to replace dysfunctional or damaged neurons. Microfluidic systems coupled with stem cell biology and biomaterials have produced exciting advances to restore vision. The current article reviews contemporary microfluidic technologies and microfluidics-enhanced bioassays, developed to interrogate cellular responses to adult retinal cues. The focus is on applications of microfluidics and microscale assays within mammalian sensory retina, or neuro retina, comprised of five types of retinal neurons (photoreceptors, horizontal, bipolar, amacrine, retinal ganglion) and one neuroglia (Müller), but excludes the non-sensory, retinal pigmented epithelium.
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6
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Induction of Heat Shock Protein 70 in Mouse RPE as an In Vivo Model of Transpupillary Thermal Stimulation. Int J Mol Sci 2020; 21:ijms21062063. [PMID: 32192227 PMCID: PMC7139698 DOI: 10.3390/ijms21062063] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/09/2020] [Accepted: 03/16/2020] [Indexed: 12/14/2022] Open
Abstract
The induction of heat shock response in the macula has been proposed as a useful therapeutic strategy for retinal neurodegenerative diseases by promoting proteostasis and enhancing protective chaperone mechanisms. We applied transpupillary 1064 nm long-duration laser heating to the mouse (C57Bl/6J) fundus to examine the heat shock response in vivo. The intensity and spatial distribution of heat shock protein (HSP) 70 expression along with the concomitant probability for damage were measured 24 h after laser irradiation in the mouse retinal pigment epithelium (RPE) as a function of laser power. Our results show that the range of heating powers for producing heat shock response while avoiding damage in the mouse RPE is narrow. At powers of 64 and 70 mW, HSP70 immunostaining indicates 90 and 100% probability for clearly elevated HSP expression while the corresponding probability for damage is 20 and 33%, respectively. Tunel staining identified the apoptotic regions, and the estimated 50% damaging threshold probability for the heating (ED50) was ~72 mW. The staining with Bestrophin1 (BEST1) demonstrated RPE cell atrophy with the most intense powers. Consequently, fundus heating with a long-duration laser provides an approachable method to develop heat shock-based therapies for the RPE of retinal disease model mice.
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7
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CRISPR, Prime Editing, Optogenetics, and DREADDs: New Therapeutic Approaches Provided by Emerging Technologies in the Treatment of Spinal Cord Injury. Mol Neurobiol 2020; 57:2085-2100. [DOI: 10.1007/s12035-019-01861-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/15/2019] [Indexed: 02/07/2023]
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8
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Zheng Z, Shang Y, Tao J, Zhang J, Sha B. Endoplasmic Reticulum Stress Signaling Pathways: Activation and Diseases. Curr Protein Pept Sci 2019; 20:935-943. [PMID: 31223084 DOI: 10.2174/1389203720666190621103145] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 02/06/2023]
Abstract
Secretory and membrane proteins are folded in the endoplasmic reticulum (ER) prior to their exit. When ER function is disturbed by exogenous and endogenous factors, such as heat shock, ultraviolet radiation, hypoxia, or hypoglycemia, the misfolded proteins may accumulate, promoting ER stress. To rescue this unfavorable situation, the unfolded protein response is activated to reduce misfolded proteins within the ER. Upon ER stress, the ER transmembrane sensor molecules inositol-requiring enzyme 1 (IRE1), RNA-dependent protein kinase (PKR)-like ER kinase (PERK), and activating transcription factor 6, are activated. Here, we discuss the mechanisms of PERK and IRE1 activation and describe two working models for ER stress initiation: the BiP-dependent model and the ligand-driven model. ER stress activation has been linked to multiple diseases, including cancers, Alzheimer's disease, and diabetes. Thus, the regulation of ER stress may provide potential therapeutic targets for these diseases.
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Affiliation(s)
- Zhi Zheng
- Department of Cell, Developmental and Integrative Biology (CDIB), University of Alabama at Birmingham, Birmingham, AL 35294, United States.,Department of General Surgery, Beijing Friendship Hospital, Capital Medical University, 95 Yong-an Road, Xi-Cheng District, Beijing 100050, China
| | - Yuxi Shang
- Department of Hematology, Fuxing Hospital, Eighth Clinical Medical College, Capital Medical University, Beijing 100038, China
| | - Jiahui Tao
- Department of Cell, Developmental and Integrative Biology (CDIB), University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Jun Zhang
- Department of General Surgery, Beijing Friendship Hospital, Capital Medical University, 95 Yong-an Road, Xi-Cheng District, Beijing 100050, China
| | - Bingdong Sha
- Department of Cell, Developmental and Integrative Biology (CDIB), University of Alabama at Birmingham, Birmingham, AL 35294, United States
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9
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Bezamat M, Deeley K, Khaliq S, Letra A, Scariot R, Silva RM, Weber ML, Bussaneli DG, Trevilatto PC, Almarza AJ, Ouyang H, Vieira AR. Are mTOR and Endoplasmic Reticulum Stress Pathway Genes Associated with Oral and Bone Diseases? Caries Res 2018; 53:235-241. [PMID: 30205378 DOI: 10.1159/000492675] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/03/2018] [Indexed: 12/21/2022] Open
Abstract
The purpose of this cohort study was to identify associations between combined oral and bone disease phenotypes and genes present in cell regulatory pathways. The studied pathways play important roles in cellular growth, proliferation, differentiation, and homeostasis. DNA samples extracted from whole saliva of 3,912 individuals were genotyped and these data analyzed according to dental caries experience, periapical lesions, periodontitis, osteoporosis, or temporomandibular joint discomfort. Samples were obtained from the Dental Registry and DNA Repository project at the University of Pittsburgh. Twenty-seven polymorphisms in eight genes related to mTOR or endoplasmic reticulum stress pathways were selected for genotyping. Allele frequencies and Hardy-Weinberg equilibrium were calculated. Analyses were performed comparing genotypes between affected and unaffected individuals for each phenotype, as well as for the associated phenotypes combined. For all analyses, we used the software PLINK with an alpha of 0.002. Borderline associations with multiple variants of several genes were found, suggesting that both pathways may be involved in the susceptibility to multiple conditions affecting the oral cavity and bones. When combining patients that had concomitant dental caries, periodontitis, and periapical pathology, several markers in RHEB showed statistically significant association. Multiple conditions affecting bone and teeth (i.e., dental caries, periodontitis, periapical lesion formation, and osteoporosis) appear to share similar underlying genetic etiological factors, which allow us to hypothesize that instead of individually, they should be studied in conjunction in human populations.
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Affiliation(s)
- Mariana Bezamat
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kathleen Deeley
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Shahryar Khaliq
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Ariadne Letra
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Endodontics, University of Texas Health Sciences Center at Houston, Houston, Texas, USA
| | - Rafaela Scariot
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Graduate Program of Health Sciences, PUC-Paraná, Curitiba, Brazil.,Department of Oral Surgery, Positivo University, Curitiba, Brazil
| | - Renato M Silva
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Endodontics, University of Texas Health Sciences Center at Houston, Houston, Texas, USA
| | - Megan L Weber
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Diego G Bussaneli
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Pediatric Dentistry, UNESP, Araraquara, Brazil
| | | | - Alejandro J Almarza
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Hongjiao Ouyang
- Department of Endodontics, Texas A&M College of Dentistry, Dallas, Texas, USA
| | - Alexandre R Vieira
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA, .,Graduate Program of Health Sciences, PUC-Paraná, Curitiba, Brazil,
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Systemic inflammation induced by lipopolysaccharide aggravates inherited retinal dystrophy. Cell Death Dis 2018; 9:350. [PMID: 29500424 PMCID: PMC5834451 DOI: 10.1038/s41419-018-0355-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 01/16/2018] [Accepted: 01/22/2018] [Indexed: 12/12/2022]
Abstract
Retinal neurodegenerative diseases involve a scenario of inflammation and cell death that leads to morphological alterations and visual impairment. Non-ocular inflammatory processes could affect neurodegenerative retinal disorders and their progression, at least in part by activating microglial cells and releasing pro-inflammatory cytokines. Our purpose was to study the consequences of a systemic inflammatory process in the progression of retinal degeneration in P23H rats, a retinitis pigmentosa (RP) model. In order to induce a mild chronic systemic inflammation, we administered low doses of lipopolysaccharide (LPS) from age P20 to P60 to dystrophic P23H rats and healthy SD rats. Visual responsiveness was assessed by electroretinography (ERG). The morphological state of the retinas was analyzed by fluorescent immunohistochemistry (IHC), evaluating the number, morphology, and connectivity of different neuronal populations by means of cell type-specific markers. Microglia density, distribution, and degree of activation were evaluated by IHC and flow cytometry. The expression levels of inflammation- and apoptosis-related genes were analyzed by qRT-PCR arrays. Low-dose LPS administration did not induce significant functional or morphological changes in the retina of SD rats, although at the molecular level, we detected expression changes in genes related to apoptosis. Otherwise, systemic injection of LPS into P23H rats induced a further deterioration in the ERG response, with greater loss of photoreceptors and worsening of synaptic connectivity, accompanied by increasing numbers of microglial cells, which also showed a more intense activation state. Several inflammation- and apoptosis-related genes were upregulated. Our results indicate that chronic exacerbation of the inflammatory response in response to LPS accelerates neurodegeneration in dystrophic P23H rats, suggesting that in patients with ocular neurodegenerative diseases, peripheral damage, as a systemic infection or chronic inflammatory process, could accelerate disease progression, and should be taken into account in order to select an appropriate therapy to revert, block or slow-down the degenerative process.
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Amato R, Catalani E, Dal Monte M, Cammalleri M, Di Renzo I, Perrotta C, Cervia D, Casini G. Autophagy-mediated neuroprotection induced by octreotide in an ex vivo model of early diabetic retinopathy. Pharmacol Res 2017; 128:167-178. [PMID: 28970178 DOI: 10.1016/j.phrs.2017.09.022] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/21/2017] [Accepted: 09/28/2017] [Indexed: 12/18/2022]
Abstract
Neuronal injury plays a major role in diabetic retinopathy (DR). Our hypothesis was that the balance between neuronal death and survival may depend on a similar equilibrium between apoptosis and autophagy and that a neuroprotectant may act by influencing this equilibrium. Ex vivo mouse retinal explants were treated with high glucose (HG) for 10days and the somatostatin analog octreotide (OCT) was used as a neuroprotectant. Chloroquine (CQ) was used as an autophagy inhibitor. Apoptotic and autophagic markers were evaluated using western blot and immunohistochemistry. HG-treated explants displayed a significant increase of apoptosis paralleled by a significant decrease of the autophagic flux, which was likely to be due to increased activity of the autophagy regulator mTOR (mammalian target of rapamycin). Treatment with OCT rescued HG-treated retinal explants from apoptosis and determined an increase of autophagic activity with concomitant mTOR inhibition. Blocking the autophagic flux with CQ completely abolished the anti-apoptotic effect of OCT. Immunohistochemical observations showed that OCT-induced autophagy is localized to populations of bipolar and amacrine cells and to ganglion cells. These observations revealed the antithetic role of apoptosis and autophagy, highlighting their equilibrium from which neuronal survival is likely to depend. These data suggest the crucial role covered by autophagy, which could be considered as a molecular target for DR neuroprotective treatment strategies.
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Affiliation(s)
- Rosario Amato
- Department of Biology, University of Pisa, Pisa, Italy
| | - Elisabetta Catalani
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, Pisa, Italy; Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
| | | | - Ilaria Di Renzo
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), University of Milano, Milano, Italy
| | - Cristiana Perrotta
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), University of Milano, Milano, Italy
| | - Davide Cervia
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, Viterbo, Italy.
| | - Giovanni Casini
- Department of Biology, University of Pisa, Pisa, Italy; Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy.
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