RESUMO
SARS-CoV-2 has been shown to cause wide-ranging ocular abnormalities and vision impairment in COVID-19 patients. However, there is limited understanding of SARS-CoV-2 in ocular transmission, tropism, and associated pathologies. The presence of viral RNA in corneal/conjunctival tissue and tears, along with the evidence of viral entry receptors on the ocular surface, has led to speculation that the eye may serve as a potential route of SARS-CoV-2 transmission. Here, we investigated the interaction of SARS-CoV-2 with cells lining the blood-retinal barrier (BRB) and the role of the eye in its transmission and tropism. The results from our study suggest that SARS-CoV-2 ocular exposure does not cause lung infection and moribund illness in K18-hACE2 mice despite the extended presence of viral remnants in various ocular tissues. In contrast, intranasal exposure not only resulted in SARS-CoV-2 spike (S) protein presence in different ocular tissues but also induces a hyperinflammatory immune response in the retina. Additionally, the long-term exposure to viral S-protein caused microaneurysm, retinal pigmented epithelium (RPE) mottling, retinal atrophy, and vein occlusion in mouse eyes. Notably, cells lining the BRB, the outer barrier, RPE, and the inner barrier, retinal vascular endothelium, were highly permissive to SARS-CoV-2 replication. Unexpectedly, primary human corneal epithelial cells were comparatively resistant to SARS-CoV-2 infection. The cells lining the BRB showed induced expression of viral entry receptors and increased susceptibility towards SARS-CoV-2-induced cell death. Furthermore, hyperglycemic conditions enhanced the viral entry receptor expression, infectivity, and susceptibility of SARS-CoV-2-induced cell death in the BRB cells, confirming the reported heightened pathological manifestations in comorbid populations. Collectively, our study provides the first evidence of SARS-CoV-2 ocular tropism via cells lining the BRB and that the virus can infect the retina via systemic permeation and induce retinal inflammation.
Assuntos
Barreira Hematorretiniana , COVID-19 , Retina , SARS-CoV-2 , SARS-CoV-2/imunologia , SARS-CoV-2/fisiologia , Animais , Barreira Hematorretiniana/virologia , COVID-19/imunologia , COVID-19/virologia , Camundongos , Humanos , Retina/virologia , Retina/imunologia , Retina/metabolismo , Enzima de Conversão de Angiotensina 2/metabolismo , Internalização do Vírus , Glicoproteína da Espícula de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/imunologia , Inflamação/imunologia , Inflamação/virologia , Betacoronavirus/fisiologia , Tropismo Viral , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Infecções por Coronavirus/patologiaRESUMO
BACKGROUND: Dimethyl fumarate (DMF) is a fumaric acid ester that exhibits immunoregulatory and anti-inflammatory properties. However, the function of DMF in autoimmune uveitis (AU) is incompletely understood, and studies comprehensively exploring the impact of DMF on immune cells are still lacking. METHODS: To explore the function of DMF in uveitis and its underlying mechanisms, we conducted single-cell RNA sequencing (scRNA-seq) on the cervical draining lymph node (CDLN) cells of normal, experimental autoimmune uveitis (EAU), and DMF-treated EAU mice. Additionally, we integrated scRNA-seq data of the retina and CDLNs to identify the potential impact of DMF on ocular immune cell infiltration. Flow cytometry was conducted to verify the potential target molecules of DMF. RESULTS: Our study showed that DMF treatment effectively ameliorated EAU symptoms. The proportional and transcriptional alterations in each immune cell type during EAU were reversed by DMF treatment. Bioinformatics analysis in our study indicated that the enhanced expression of Pim1 and Cxcr4 in EAU was reversed by DMF treatment. Further experiments demonstrated that DMF restored the balance between effector T (Teff) /regulatory T (Treg) cells through inhibiting the pathway of PIM1-protein kinase B (AKT)-Forkhead box O1 (FOXO1). By incorporating the scRNA-seq data of the retina from EAU mice into analysis, our study identified that T cells highly expressing Pim1 and Cxcr4 were enriched in the retina. DMF repressed the ocular infiltration of Teff cells, and this effect might depend on its inhibition of PIM1 and CXCR4 expression. Additionally, our study indicated that DMF might reduce the proportion of plasma cells by inhibiting PIM1 expression in B cells. CONCLUSIONS: DMF effectively attenuated EAU symptoms. During EAU, DMF reversed the Teff/Treg cell imbalance and suppressed the ocular infiltration of Teff cells by inhibiting PIM1 and CXCR4 expression. Thus, DMF may act as a new drug option for the treatment of AU.
Assuntos
Anti-Inflamatórios não Esteroides , Doenças Autoimunes , Fumarato de Dimetilo , Imunossupressores , Retina , Uveíte , Fumarato de Dimetilo/administração & dosagem , Fumarato de Dimetilo/farmacologia , Uveíte/genética , Uveíte/imunologia , Uveíte/terapia , Doenças Autoimunes/genética , Doenças Autoimunes/imunologia , Doenças Autoimunes/terapia , Análise da Expressão Gênica de Célula Única , Modelos Animais de Doenças , Animais , Camundongos , Feminino , Camundongos Endogâmicos C57BL , Receptores CXCR4/genética , Receptores CXCR4/metabolismo , Proteínas Proto-Oncogênicas c-pim-1/genética , Proteínas Proto-Oncogênicas c-pim-1/metabolismo , Transcrição Gênica , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/imunologia , Atlas como Assunto , Imunossupressores/administração & dosagem , Imunossupressores/farmacologia , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/farmacologia , Retina/efeitos dos fármacos , Retina/imunologia , Linfonodos/efeitos dos fármacos , Linfonodos/imunologiaRESUMO
Activated retina-specific T cells that have acquired the ability to break through the blood-retinal barrier are thought to be causally involved in autoimmune uveitis, a major cause of human blindness. It is unclear where these autoreactive T cells first become activated, given that their cognate antigens are sequestered within the immune-privileged eye. We demonstrate in a novel mouse model of spontaneous uveitis that activation of retina-specific T cells is dependent on gut commensal microbiota. Retina-specific T cell activation involved signaling through the autoreactive T cell receptor (TCR) in response to non-cognate antigen in the intestine and was independent of the endogenous retinal autoantigen. Our findings not only have implications for the etiology of human uveitis, but also raise the possibility that activation of autoreactive TCRs by commensal microbes might be a more common trigger of autoimmune diseases than is currently appreciated.
Assuntos
Intestinos/imunologia , Microbiota/imunologia , Retina/imunologia , Linfócitos T/imunologia , Uveíte/imunologia , Animais , Antígenos de Bactérias/administração & dosagem , Autoantígenos/imunologia , Autoimunidade , Barreira Hematorretiniana/imunologia , Células Cultivadas , Modelos Animais de Doenças , Proteínas do Olho/genética , Proteínas do Olho/imunologia , Proteínas do Olho/metabolismo , Tolerância Imunológica , Intestinos/microbiologia , Ativação Linfocitária , Camundongos Endogâmicos , Camundongos Knockout , Receptores de Antígenos de Linfócitos T/metabolismo , Proteínas de Ligação ao Retinol/genética , Proteínas de Ligação ao Retinol/imunologia , Proteínas de Ligação ao Retinol/metabolismo , Uveíte/microbiologiaRESUMO
Background and Objectives: Age-related macular degeneration (AMD) is one of the leading causes of central vision loss among elderly patients, and its dry form accounts for the majority of cases. Although several causes and mechanisms for the development and progression of AMD have previously been identified, the pathogenesis of this complex disease is still not entirely understood. As inflammation and immune system involvement are strongly suggested to play a central role in promoting the degenerative process and stimulating the onset of complications, we aimed to analyze the frequency of serum anti-retinal (ARAs) and anti-endothelial cell antibodies (AECAs) in patients with dry AMD and to determine their relationship with the clinical features of the disease, notably the area of geographic atrophy (GA). Materials and Methods: This study included 41 patients with advanced-stage dry AMD and 50 healthy controls without AMD, matched for gender and age. ARAs were detected by indirect immunofluorescence using monkey retina as an antigen substrate, and the presence of AECAs was determined using cultivated human umbilical vein endothelial cells and primate skeletal muscle. Results: ARAs were detected in 36 (87.8%) AMD patients (titers ranged from 1:20 to 1:320) and in 16 (39.0%) (titers ranged from 1:10 to 1:40) controls (p = 0.0000). Twenty of the forty-one patients (48.8%) were positive for AECAs, while in the control group, AECAs were present only in five sera (10.0%). The titers of AECAs in AMD patients ranged from 1:100 to 1:1000, and in the control group, the AECA titers were 1:100 (p = 0.0001). There were no significant correlations between the presence of AECAs and disease activity. Conclusions: This study demonstrates a higher prevalence of circulating AECAs in patients with dry AMD; however, no correlation was found between the serum levels of these autoantibodies and the area of GA.
Assuntos
Autoanticorpos , Atrofia Geográfica , Degeneração Macular , Humanos , Masculino , Feminino , Idoso , Atrofia Geográfica/sangue , Atrofia Geográfica/imunologia , Degeneração Macular/sangue , Degeneração Macular/complicações , Autoanticorpos/sangue , Pessoa de Meia-Idade , Idoso de 80 Anos ou mais , Células Endoteliais/imunologia , Retina/imunologia , Estudos de Casos e ControlesRESUMO
The complement cascade is a vital system in the human body's defense against pathogens. During the natural aging process, it has been observed that this system is imperative for ensuring the integrity and homeostasis of the retina. While this system is critical for proper host defense and retinal integrity, it has also been found that dysregulation of this system may lead to certain retinal pathologies, including geographic atrophy and diabetic retinopathy. Targeting components of the complement system for retinal diseases has been an area of interest, and in vivo, ex vivo, and clinical trials have been conducted in this area. Following clinical trials, medications targeting the complement system for retinal disease have also become available. In this manuscript, we discuss the pathophysiology of complement dysfunction in the retina and specific pathologies. We then describe the results of cellular, animal, and clinical studies targeting the complement system for retinal diseases. We then provide an overview of complement inhibitors that have been approved by the Food and Drug Administration (FDA) for geographic atrophy. The complement system in retinal diseases continues to serve as an emerging therapeutic target, and further research in this field will provide additional insights into the mechanisms and considerations for treatment of retinal pathologies.
Assuntos
Proteínas do Sistema Complemento , Doenças Retinianas , Humanos , Doenças Retinianas/tratamento farmacológico , Doenças Retinianas/fisiopatologia , Doenças Retinianas/imunologia , Proteínas do Sistema Complemento/fisiologia , Animais , Inativadores do Complemento/uso terapêutico , Inativadores do Complemento/farmacologia , Retinopatia Diabética/tratamento farmacológico , Retinopatia Diabética/fisiopatologia , Retina/efeitos dos fármacos , Retina/imunologiaRESUMO
Genetic polymorphisms in the region of the trimeric serine hydrolase high-temperature requirement 1 (HTRA1) are associated with increased risk of age-related macular degeneration (AMD) and disease progression, but the precise biological function of HtrA1 in the eye and its contribution to disease etiologies remain undefined. In this study, we have developed an HtrA1-blocking Fab fragment to test the therapeutic hypothesis that HtrA1 protease activity is involved in the progression of AMD. Next, we generated an activity-based small-molecule probe (ABP) to track target engagement in vivo. In addition, we used N-terminomic proteomic profiling in preclinical models to elucidate the in vivo repertoire of HtrA1-specific substrates, and identified substrates that can serve as robust pharmacodynamic biomarkers of HtrA1 activity. One of these HtrA1 substrates, Dickkopf-related protein 3 (DKK3), was successfully used as a biomarker to demonstrate the inhibition of HtrA1 activity in patients with AMD who were treated with the HtrA1-blocking Fab fragment. This pharmacodynamic biomarker provides important information on HtrA1 activity and pharmacological inhibition within the ocular compartment.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Anticorpos Anti-Idiotípicos/farmacologia , Atrofia Geográfica/tratamento farmacológico , Serina Peptidase 1 de Requerimento de Alta Temperatura A/genética , Degeneração Macular/tratamento farmacológico , Proteínas Adaptadoras de Transdução de Sinal/isolamento & purificação , Idoso , Animais , Anticorpos Anti-Idiotípicos/genética , Anticorpos Anti-Idiotípicos/imunologia , Biomarcadores/sangue , Progressão da Doença , Feminino , Predisposição Genética para Doença , Genótipo , Atrofia Geográfica/sangue , Atrofia Geográfica/genética , Atrofia Geográfica/imunologia , Serina Peptidase 1 de Requerimento de Alta Temperatura A/antagonistas & inibidores , Humanos , Fragmentos Fab das Imunoglobulinas/imunologia , Fragmentos Fab das Imunoglobulinas/farmacologia , Degeneração Macular/sangue , Degeneração Macular/genética , Degeneração Macular/imunologia , Masculino , Polimorfismo de Nucleotídeo Único/genética , Proteoma/genética , Proteoma/imunologia , Ratos , Retina/efeitos dos fármacos , Retina/imunologia , Retina/patologia , Bibliotecas de Moléculas Pequenas/farmacologiaRESUMO
Nomacopan, a drug originally derived from tick saliva, has dual functions of sequestering leukotriene B4 (LTB4) and inhibiting complement component 5 (C5) activation. Nomacopan has been shown to provide therapeutic benefit in experimental autoimmune uveitis (EAU). Longer acting forms of nomacopan were more efficacious in mouse EAU models, and the long-acting variant that inhibited only LTB4 was at least as effective as the long-acting variant that inhibited both C5 and LTB4, preventing structural damage to the retina and a significantly reducing effector T helper 17 cells and inflammatory macrophages. Increased levels of LTB4 and C5a (produced upon C5 activation) were detected during disease progression. Activated retinal lymphocytes were shown to express LTB4 receptors (R) in vitro and in inflamed draining lymph nodes. Levels of LTB4R-expressing active/inflammatory retinal macrophages were also increased. Within the draining lymph node CD4+ T-cell population, 30% expressed LTB4R+ following activation in vitro, whereas retinal infiltrating cells expressed LTB4R and C5aR. Validation of expression of those receptors in human uveitis and healthy tissues suggests that infiltrating cells could be targeted by inhibitors of the LTB4-LTB4 receptor 1 (BLT1) pathway as a novel therapeutic approach. This study provides novel data on intraocular LTB4 and C5a in EAU, their associated receptor expression by retinal infiltrating cells in mouse and human tissues, and in attenuating EAU via the dual inhibitor nomacopan.
Assuntos
Leucotrieno B4/metabolismo , Receptores do Leucotrieno B4/metabolismo , Retina/metabolismo , Uveíte/imunologia , Uveíte/metabolismo , Animais , Produtos Biológicos/farmacologia , Complemento C5a/antagonistas & inibidores , Complemento C5a/metabolismo , Modelos Animais de Doenças , Feminino , Humanos , Leucotrieno B4/antagonistas & inibidores , Camundongos , Camundongos Endogâmicos C57BL , Receptores do Leucotrieno B4/antagonistas & inibidores , Retina/imunologia , Células Th17/imunologiaRESUMO
To study the macroglia and microglia and the immune role in long-time light exposure in rat eyes, we performed glial cell characterization along the time-course of retinal degeneration induced by chronic exposure to low-intensity light. Animals were exposed to light for periods of 2, 4, 6, or 8 days, and the retinal glial response was evaluated by immunohistochemistry, western blot and real-time reverse transcription polymerase chain reaction. Retinal cells presented an increased expression of the macroglia marker GFAP, as well as increased mRNA levels of microglia markers Iba1 and CD68 after 6 days. Also, at this time-point, we found a higher number of Iba1-positive cells in the outer nuclear layer area; moreover, these cells showed the characteristic activated-microglia morphology. The expression levels of immune mediators TNF, IL-6, and chemokines CX3CR1 and CCL2 were also significantly increased after 6 days. All the events of glial activation occurred after 5-6 days of constant light exposure, when the number of photoreceptor cells has already decreased significantly. Herein, we demonstrated that glial and immune activation are secondary to neurodegeneration; in this scenario, our results suggest that photoreceptor death is an early event that occurs independently of glial-derived immune responses.
Assuntos
Interleucina-6 , Neuroglia , Lesões por Radiação , Retina , Degeneração Retiniana , Animais , Quimiocinas/genética , Quimiocinas/metabolismo , Interleucina-6/metabolismo , Luz , Neuroglia/imunologia , RNA Mensageiro/genética , Lesões por Radiação/etiologia , Lesões por Radiação/imunologia , Ratos , Retina/imunologia , Retina/efeitos da radiação , Degeneração Retiniana/etiologia , Degeneração Retiniana/imunologiaRESUMO
Endophthalmitis is a devastating infection that can cause blindness. Over half of Bacillus endophthalmitis cases result in significant loss of useful vision. Bacillus produces many virulence factors that may contribute to retinal damage and robust inflammation. We analyzed Bacillus immune inhibitor A (InhA) metalloproteases in the context of this disease, hypothesizing that InhAs contribute to Bacillus intraocular virulence and inflammation. We analyzed phenotypes and infectivity of wild-type (WT), InhA1-deficient (ΔinhA1), InhA2-deficient (ΔinhA2), or InhA1, A2, and A3-deficient (ΔinhA1-3) Bacillus thuringiensis. In vitro analysis of growth, proteolysis, and cytotoxicity were compared. WT and InhA mutants were similarly cytotoxic to retinal cells. The ΔinhA1 and ΔinhA2 mutants entered log-phase growth earlier than WT B. thuringiensis. Proteolysis by the ΔinhA1-3 mutant was decreased, but this strain grew similar to WT in vitro. Experimental endophthalmitis was initiated by intravitreally infecting C57BL/6J mice with 200 CFU of WT B. thuringiensis or InhA mutants. Eyes were analyzed for intraocular Bacillus and myeloperoxidase concentrations, retinal function loss, and gross histological changes. Eyes infected with the ΔinhA1 or ΔinhA2 mutant strains contained greater numbers of bacteria than eyes infected with WT throughout the infection course. Eyes infected with single mutants had inflammation and retinal function loss similar to eyes infected with the WT strain. Eyes infected with the ΔinhA1-3 mutant cleared the infection. Quantitative real-time PCR (qRT-PCR) results suggested that there may be compensatory expression of the other InhAs in the single InhA mutant. These results indicate that together, the InhA metalloproteases contribute to the severity of infection and inflammation in Bacillus endophthalmitis.
Assuntos
Bacillus thuringiensis/imunologia , Endoftalmite/imunologia , Metaloendopeptidases/imunologia , Metaloproteases/imunologia , Virulência/imunologia , Animais , Células Cultivadas , Modelos Animais de Doenças , Endoftalmite/microbiologia , Infecções Oculares Bacterianas/imunologia , Infecções Oculares Bacterianas/microbiologia , Humanos , Inflamação/imunologia , Inflamação/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Retina/imunologia , Retina/microbiologiaRESUMO
This study focuses on gene expression differences between early retinal states that ultimately lead to normal development, late onset retinoblastoma, or rapid bilateral retinoblastoma tumors. The late-onset and early-onset retinoblastoma tumor cells are remarkably similar to normally proliferating retinal progenitor cells, but they fail to properly express differentiation markers associated with normal development. Further, early-onset retinoblastoma tumor cells express a robust immune gene expression signature followed by accumulation of dendritic, monocyte, macrophage, and T-lymphocyte cells in the retinoblastoma tumors. This characteristic was not shared by either normal retinae or late-onset retinoblastomas. Comparison of our data with other human and mouse retinoblastoma tumor gene expression significantly confirmed, that the immune signature is present in tumors from each species. Strikingly, we observed that the immune signature in both mouse and human tumors was most highly evident in those with the lowest proliferative capacity. We directly assessed this relationship in human retinoblastoma tumors by co-analyzing proliferation and immune cell recruitment by immunohistochemistry, uncovering a significant inverse relationship between increased immune-cell infiltration in tumors and reduced tumor cell proliferation. Directly inhibiting proliferation with a PI3K/mTOR inhibitor significantly increased the number of CD45+ immune cells in the retina. This work establishes an in vivo model for the rapid recruitment of immune cells to tumorigenic neural tissue.
Assuntos
Retinoblastoma/imunologia , Animais , Ciclo Celular , Proliferação de Células , Humanos , Camundongos , Neoplasias Experimentais , Retina/imunologia , Retina/metabolismo , Retinoblastoma/metabolismoRESUMO
BACKGROUND: To investigate age-related severity, patterns of retinal structural damage, and functional visual recovery in pediatric and adult cohorts of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) optic neuritis (ON). METHODS: All MOGAD patients from the 5 participating centers were included. Patients with initial manifestation <18 years were included in the pediatric (MOGADped) cohort and patients with ≥18 years in the adult (MOGADadult) cohort. For patients with MOGAD ON, examinations at least ≥6 months after ON onset were included in the analyses. Using spectral domain optical coherence tomography (SD-OCT), we acquired peripapillary retinal nerve fiber layer thickness (pRNFL) and volumes of combined ganglion cell and inner plexiform layer (GCIPL). High- and 2.5% low-contrast visual acuity (HCVA, LCVA) and visual-evoked potentials (VEP) were obtained. RESULTS: Twenty MOGADped (10.3±3.7 years, 30 MOGAD ON eyes) and 39 MOGADadult (34.9±11.6 years, 42 MOGAD ON eyes) patients were included. The average number of ON episodes per ON eye was similar in both groups (1.8±1.3 and 2.0±1.7). In both pediatric and adult MOGAD, ON led to pronounced neuroaxonal retinal atrophy (pRNFL: 63.1±18.7 and 64.3±22.9 µm; GCIPL: 0.42±0.09 and 0.44±0.13 mm3, respectively) and moderate delay of the VEP latencies (117.9±10.7 and 118.0±14.5 ms). In contrast, visual acuity was substantially better in children (HCVA: 51.4±9.3 vs. 35.0±20.6 raw letters, p=0.001; LCVA: 22.8±14.6 vs. 13.5±16.4, p=0.028). Complete visual recovery (HCVA-logMAR 0.0) occurred in 73.3% of MOGADped and 31% MOGADadults ON eyes, while 3.3% and 31% demonstrated moderate to severe (logMAR > 0.5) visual impairment. Independent of retinal atrophy, age at ON onset significantly correlated with visual outcome. CONCLUSION: Pediatric MOGAD ON showed better visual recovery than adult MOGAD ON despite profound and almost identical neuroaxonal retinal atrophy. Age-related cortical neuroplasticity may account for the substantial discrepancy between structural changes and functional outcomes.
Assuntos
Doenças Autoimunes do Sistema Nervoso , Neurite Óptica/fisiopatologia , Retina , Transtornos da Visão/fisiopatologia , Acuidade Visual , Adolescente , Adulto , Fatores Etários , Atrofia/imunologia , Doenças Autoimunes do Sistema Nervoso/classificação , Doenças Autoimunes do Sistema Nervoso/complicações , Doenças Autoimunes do Sistema Nervoso/diagnóstico por imagem , Criança , Pré-Escolar , Estudos de Coortes , Potenciais Evocados Visuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Glicoproteína Mielina-Oligodendrócito/imunologia , Neurite Óptica/complicações , Neurite Óptica/imunologia , Recuperação de Função Fisiológica , Retina/diagnóstico por imagem , Retina/imunologia , Retina/fisiopatologia , Degeneração Retiniana/imunologia , Degeneração Retiniana/fisiopatologia , Tomografia de Coerência Óptica , Transtornos da Visão/imunologia , Acuidade Visual/imunologiaRESUMO
Proteinopathies result from aberrant folding and accumulation of specific proteins. Currently, there is a lack of knowledge about the factors that influence disease progression, making this a key challenge for the development of therapies for proteinopathies. Because of the similarities between transmissible spongiform encephalopathies (TSEs) and other protein misfolding diseases, TSEs can be used to understand other proteinopathies. Bovine spongiform encephalopathy (BSE) is a TSE that occurs in cattle and can be subdivided into three strains: classic BSE and atypical BSEs (H and L types) that have shorter incubation periods. The NACHT, LRR, and PYD domains-containing protein 3 inflammasome is a critical component of the innate immune system that leads to release of IL-1ß. Macroautophagy is an intracellular mechanism that plays an essential role in protein clearance. In this study, the retina was used as a model to investigate the relationship between disease incubation period, prion protein accumulation, neuroinflammation, and changes in macroautophagy. We demonstrate that atypical BSEs present with increased prion protein accumulation, neuroinflammation, and decreased autophagy. This work suggests a relationship between disease time course, neuroinflammation, and the autophagic stress response, and may help identify novel therapeutic biomarkers that can delay or prevent the progression of proteinopathies.
Assuntos
Autofagia/fisiologia , Encefalopatia Espongiforme Bovina/patologia , Inflamação/patologia , Proteínas PrPSc/patogenicidade , Animais , Bovinos , Encefalopatia Espongiforme Bovina/imunologia , Inflamação/imunologia , Masculino , Deficiências na Proteostase/imunologia , Deficiências na Proteostase/patologia , Retina/imunologia , Retina/patologiaRESUMO
Interleukin-1α (IL-1α) is an alarmin involved in the recruitment of macrophages and neutrophils during tissue inflammation. IL-1α can undergo cleavage by proteases, such as calpain-1, that enhances IL-1α binding to its receptor, although proteolytic cleavage is not necessary for biological activity. Macrophages and neutrophils are involved in the retinal inflammation associated with development of AIDS-related human cytomegalovirus (HCMV) retinitis. We therefore performed studies to test the hypothesis that IL-1α gene expression is stimulated intraocularly during retinitis development using two mouse models of murine cytomegalovirus (MCMV) retinitis that differ in method of immunosuppression, one by retrovirus-induced immunosuppression (MAIDS) and the other by corticosteroid-induced immunosuppression. MCMV-infected eyes of groups of retinitis-susceptible mice with MAIDS of 10 weeks duration (MAIDS-10 mice) and retinitis-susceptible corticosteroid-treated mice showed significant stimulation of IL-1α mRNA. Western blot analysis confirmed IL-1α protein production within the MCMV-infected eyes of MAIDS-10 mice. Whereas significant intraocular calpain-1 mRNA and protein production were also observed within MCMV-infected eyes of MAIDS-10 mice, the MCMV-infected eyes of retinitis-susceptible corticosteroid-treated mice showed a pattern of mRNA synthesis equivalent to that found within the MCMV-infected eyes of healthy mice that fail to develop retinitis. Our findings suggest a role for the alarmin IL-1α in the pathogenesis of MCMV retinitis in immunosuppressed mice. These findings may extend to the pathogenesis of HCMV retinitis in patients with AIDS or other forms of immunosuppression.
Assuntos
Retinite por Citomegalovirus/imunologia , Interleucina-1alfa/imunologia , Síndrome de Imunodeficiência Adquirida Murina/imunologia , Muromegalovirus/imunologia , Retina/imunologia , Animais , Modelos Animais de Doenças , Feminino , Tolerância Imunológica/imunologia , Terapia de Imunossupressão/métodos , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , RNA Mensageiro/imunologiaRESUMO
Endoplasmic reticulum (ER) stress response has been implicated in a variety of pathophysiological conditions, including infectious and inflammatory diseases. However, its contribution in ocular bacterial infections, such as endophthalmitis, which often cause blindness is not known. Here, using a mouse model of Staphylococcus (S.) aureus endophthalmitis, our study demonstrates the induction of inositol-requiring enzyme 1α (IRE1α) and splicing of X-box binding protein-1 (Xbp1) branch of the ER-stress pathway, but not the other classical ER stress sensors. Interestingly, S aureus-induced ER stress response was found to be dependent on Toll-like receptor 2 (TLR2), as evident by reduced expression of IRE1α and Xbp1 mRNA splicing in TLR2 knockout mouse retina. Pharmacological inhibition of IRE1α using 4µ8C or experiments utilizing IRE1α-/- macrophages revealed that IRE1α positively regulates S aureus-induced inflammatory responses. Moreover, IRE1α inhibition attenuated S aureus-triggered NF-κB, p38, and ERK pathways activation and cells treated with these pathway-specific inhibitors reduced Xbp1 splicing, suggesting a positive feedback inhibition. In vivo, inhibition of IRE1α diminished the intraocular inflammation and reduced PMN infiltration in mouse eyes, but, increased the bacterial burden and caused more retinal tissue damage. These results revealed a critical role of the IRE1α/XBP1 pathway as a regulator of TLR2-mediated protective innate immune responses in S aureus-induced endophthalmitis.
Assuntos
Endoftalmite/imunologia , Endorribonucleases/metabolismo , Imunidade Inata , Proteínas Serina-Treonina Quinases/metabolismo , Receptor 2 Toll-Like/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Endoftalmite/genética , Endorribonucleases/genética , Feminino , Sistema de Sinalização das MAP Quinases , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Proteínas Serina-Treonina Quinases/genética , Retina/imunologia , Retina/microbiologia , Staphylococcus aureus/patogenicidade , Receptor 2 Toll-Like/genética , Proteína 1 de Ligação a X-Box/genética , Proteína 1 de Ligação a X-Box/metabolismo , Proteínas Quinases p38 Ativadas por MitógenoRESUMO
OBJECTIVE: Microglia/macrophage activation is previously reported to be involved in various ocular diseases. However, the separate role of M1/M2 phenotype microglia/macrophage in the pathological process of oxygen-induced retinopathy (OIR) remains unknown. In this research, we explored the role and regulatory mechanism of M1/M2 microglia/macrophage in OIR in C57BL/6J mice. Furthermore, we demonstrated the time phase of M1/M2 shifting of microglia/macrophage during the natural process of OIR, which is very essential for further investigations. MATERIALS AND METHODS: C57BL/6j pups were exposed to hyperoxia environment from postnatal 7(P7) to P12 then returned to normoxia. The mice were then euthanized, and the eyes were harvested at a series of time points for further investigation. The M1/M2 phenotype microglia/macrophage activity was presented by immunofluorescent staining and real-time quantitative polymerase chain reaction (qPCR). The NF-κb-STAT3 signaling and IL-4-STAT6-PPAR-γ signaling pathway activity was examined by western blot analysis. RESULTS: The microglia/macrophage were activated when the OIR model was set up after P12. The M1 microglia/macrophage activation was found in neovascularization (NV) tufts in both central and peripheral retina, which started from P12 when the mice were returned to normoxia environment and peaked at P17. During this period of time, the NF-κb-STAT3 signaling pathway was activated, resulting in the upregulated M1 phenotype microglia/macrophage polarization, along with the enhanced inflammatory cytokine expression including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1ß. Consequently, the NV tufts were observed from P12 and the volume continued to increase until P17. However, the M2 phenotype microglia/macrophage activity took over during the late phase of OIR started from P17. The IL-4-STAT6-PPAR-γ signaling activity was upregulated from P17 and peaked at P20, inducing M2 phenotype microglia polarization, which consequently led to the inhibition of inflammatory cytokines and spontaneous regression of NV tufts. CONCLUSIONS: Microglia/macrophage participate actively in the natural process of OIR in mice, and two phenotypes exert different functions. Treatment modulating microglia/macrophage polarize toward M2 phenotype might be a novel and promising method for ocular neovascular diseases such as retinopathy of prematurity (ROP), wet age-related macular degeneration (wAMD), and diabetic retinopathy (DR).
Assuntos
Macrófagos/imunologia , Microglia/imunologia , Doenças Retinianas/imunologia , Animais , Citocinas/imunologia , Camundongos Endogâmicos C57BL , NF-kappa B/imunologia , Oxigênio , PPAR gama/imunologia , Fenótipo , Retina/imunologia , Fator de Transcrição STAT3/imunologia , Fator de Transcrição STAT6/imunologia , Transdução de SinaisRESUMO
Age-related macular degeneration (AMD) is a leading cause of visual impairment of the elderly population. Since AMD is a multifactorial age-related disease with various genetic risk factors, the understanding of its complex pathophysiology is still limited. However, animal experiments, genome-wide association data and the molecular profiling of AMD patient samples have highlighted a key role of systemic and local immune processes that contribute to this chronic eye disease. In this overview article, we concentrate on the role of lymphocytes and mononuclear phagocytes and their interplay in triggering a persistent immune response in the AMD retina. We preferentially review findings from human immune cell analyses and complement these with related findings in experimental models. We conclude that both immune cell types as their signaling network may be a rich source to identify novel molecular targets for immunomodulation in AMD.
Assuntos
Linfócitos B/imunologia , Linfócitos T CD8-Positivos/imunologia , Degeneração Macular/imunologia , Fagócitos/imunologia , Células Th1/imunologia , Células Th17/imunologia , Idoso de 80 Anos ou mais , Proteínas do Sistema Complemento/imunologia , Humanos , Imunomodulação/fisiologia , Degeneração Macular/patologia , Retina/imunologia , Retina/patologia , Transtornos da Visão/imunologiaRESUMO
Previous studies have demonstrated that ocular injury can lead to prompt infiltration of bone-marrow-derived peripheral monocytes into the retina. However, the ability of these cells to integrate into the tissue and become microglia has not been investigated. Here we show that such peripheral monocytes that infiltrate into the retina after ocular injury engraft permanently, migrate to the three distinct microglia strata, and adopt a microglia-like morphology. In the absence of ocular injury, peripheral monocytes that repopulate the retina after depletion with colony-stimulating factor 1 receptor (CSF1R) inhibitor remain sensitive to CSF1R inhibition and can be redepleted. Strikingly, consequent to ocular injury, the engrafted peripheral monocytes are resistant to depletion by CSF1R inhibitor and likely express low CSF1R. Moreover, these engrafted monocytes remain proinflammatory, expressing high levels of MHC-II, IL-1ß, and TNF-α over the long term. The observed permanent neuroglia remodeling after injury constitutes a major immunological change that may contribute to progressive retinal degeneration. These findings may also be relevant to other degenerative conditions of the retina and the central nervous system.
Assuntos
Traumatismos Oculares/imunologia , Monócitos/imunologia , Neuroglia/imunologia , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/antagonistas & inibidores , Retina/imunologia , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Diferenciação Celular/efeitos dos fármacos , Traumatismos Oculares/genética , Traumatismos Oculares/fisiopatologia , Feminino , Humanos , Interleucina-1beta/genética , Interleucina-1beta/imunologia , Masculino , Camundongos , Monócitos/citologia , Monócitos/efeitos dos fármacos , Neuroglia/citologia , Neuroglia/efeitos dos fármacos , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genética , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/imunologia , Retina/efeitos dos fármacosRESUMO
Autoimmune optic neuritis (AON), a model of multiple sclerosis-associated optic neuritis, is accompanied by degeneration of retinal ganglion cells (RGCs) and optic nerve demyelination and axonal loss. In order to investigate the role of N-methyl-d-aspartate (NMDA) receptors in mediating RGC degeneration, upstream changes in the optic nerve actin cytoskeleton and associated deterioration in visual function, we induced AON in Brown Norway rats by immunization with myelin oligodendrocyte glycoprotein. Subsequently, visual acuity was assessed by recording visual evoked potentials and electroretinograms prior to extraction of optic nerves for western blot analysis and retinas for quantification of RGCs. As previously reported, in Brown Norway rats RGC degeneration is observed prior to onset of immune cell infiltration and demyelination of the optic nerves. However, within the optic nerve, destabilization of the actin cytoskeleton could be seen as indicated by an increase in the globular to filamentous actin ratio. Interestingly, these changes could be mimicked by intravitreal injection of glutamate, and similarly blocked by application of the NMDA receptor blocker MK-801, leading us to propose that prior to optic nerve lesion formation, NMDA receptor activation within the retina leads to retinal calcium accumulation, actin destabilization within the optic nerve as well as a deterioration of visual acuity during AON.
Assuntos
Neurite Óptica/metabolismo , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/metabolismo , Retina/metabolismo , Animais , Maleato de Dizocilpina/farmacologia , Encefalomielite Autoimune Experimental/induzido quimicamente , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/metabolismo , Potenciais Evocados Visuais/efeitos dos fármacos , Potenciais Evocados Visuais/fisiologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Glicoproteína Mielina-Oligodendrócito/toxicidade , Nervo Óptico/efeitos dos fármacos , Nervo Óptico/imunologia , Nervo Óptico/metabolismo , Neurite Óptica/induzido quimicamente , Neurite Óptica/imunologia , Ratos , Ratos Endogâmicos BN , Receptores de N-Metil-D-Aspartato/imunologia , Retina/efeitos dos fármacos , Retina/imunologiaRESUMO
Autoantibodies (AAbs) against retinal antigens can be found in patients with cancer and unexplained vision loss unrelated to the cancer metastasis. Cancer-associated retinopathy (CAR) is a rare paraneoplastic visual syndrome mediated by AAbs. Our goal was to determine whether CAR patients with different malignancies have a specific AAb or repertoire of AAbs that could serve as biomarkers for retinal disease. We found AAbs against 12 confirmed retinal antigens, with α-enolase being the most frequently recognized. The significant finding of the study was a high incidence of anti-aldolase AAbs in colon-CAR, anti-CAII in prostate-CAR, and anti-arrestin in skin melanoma patients thus these AAbs could serve as biomarkers in the context of clinical presentation and could support the diagnosis of CAR. However, a lack of AAb restriction to any one antigenic protein or to one retinal cellular location makes screening for a CAR biomarker challenging.
Assuntos
Autoanticorpos/sangue , Biomarcadores Tumorais/sangue , Neoplasias do Colo/imunologia , Síndromes Paraneoplásicas Oculares/imunologia , Neoplasias da Próstata/imunologia , Retina/patologia , Idoso , Arrestina/imunologia , Autoantígenos/imunologia , Neoplasias do Colo/diagnóstico , Neoplasias do Colo/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Síndromes Paraneoplásicas Oculares/diagnóstico , Síndromes Paraneoplásicas Oculares/epidemiologia , Fosfopiruvato Hidratase/imunologia , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/epidemiologia , Retina/imunologia , Estados Unidos/epidemiologiaRESUMO
BACKGROUND: Macular fibrosis causes irreparable vision loss in neovascular age-related macular degeneration (nAMD) even with anti-vascular endothelial growth factor (VEGF) therapy. Inflammation is known to play an important role in macular fibrosis although the underlying mechanism remains poorly defined. The aim of this study was to understand how infiltrating macrophages and complement proteins may contribute to macular fibrosis. METHODS: Subretinal fibrosis was induced in C57BL/6J mice using the two-stage laser protocol developed by our group. The eyes were collected at 10, 20, 30 and 40 days after the second laser and processed for immunohistochemistry for infiltrating macrophages (F4/80 and Iba-1), complement components (C3a and C3aR) and fibrovascular lesions (collagen-1, Isolectin B4 and α-SMA). Human retinal sections with macular fibrosis were also used in the study. Bone marrow-derived macrophages (BMDMs) from C57BL/6J mice were treated with recombinant C3a, C5a or TGF-ß for 48 and 96 h. qPCR, Western blot and immunohistochemistry were used to examine the expression of myofibroblast markers. The involvement of C3a-C3aR pathway in macrophage to myofibroblast transition (MMT) and subretinal fibrosis was further investigated using a C3aR antagonist (C3aRA) and a C3a blocking antibody in vitro and in vivo. RESULTS: Approximately 20~30% of F4/80+ (or Iba-1+) infiltrating macrophages co-expressed α-SMA in subretinal fibrotic lesions both in human nAMD eyes and in the mouse model. TGF-ß and C3a, but not C5a treatment, significantly upregulated expression of α-SMA, fibronectin and collagen-1 in BMDMs. C3a-induced upregulation of α-SMA, fibronectin and collagen-1 in BMDMs was prevented by C3aRA treatment. In the two-stage laser model of induced subretinal fibrosis, treatment with C3a blocking antibody but not C3aRA significantly reduced vascular leakage and Isolectin B4+ lesions. The treatment did not significantly alter collagen-1+ fibrotic lesions. CONCLUSIONS: MMT plays a role in macular fibrosis secondary to nAMD. MMT can be induced by TGF-ß and C3a but not C5a. Further research is required to fully understand the role of MMT in macular fibrosis. Macrophage to myofibroblast transition (MMT) contributes to subretinal fibrosis. Subretinal fibrosis lesions contain various cell types, including macrophages and myofibroblasts, and are fibrovascular. Myofibroblasts are key cells driving pathogenic fibrosis, and they do so by producing excessive amount of extracellular matrix proteins. We have found that infiltrating macrophages can transdifferentiate into myofibroblasts, a phenomenon termed macrophage to myofibroblast transition (MMT) in macular fibrosis. In addition to TGF-ß1, C3a generated during complement activation in CNV can also induce MMT contributing to macular fibrosis. RPE = retinal pigment epithelium. BM = Bruch's membrane. MMT = macrophage to myofibroblast transition. TGFB = transforming growth factor ß. a-SMA = alpha smooth muscle actin. C3a = complement C3a.