Dataset Information

Progranulin deficiency in Iba-1⁺ myeloid cells exacerbates choroidal neovascularization by perturbation of lysosomal function and abnormal inflammation.

ABSTRACT:

Background

Age-related macular degeneration (AMD) is the principal cause of permanent blindness among elderly individuals worldwide. Chronic inflammation in the subretinal space is associated with a progression of exudative AMD. Progranulin (PGRN) is a growth factor secreted from myeloid cells and plays an important role in controlling the lysosomal function. A deficiency in PGRN leads to inflammation of the neurons in the central nervous system. The purpose of this study was to investigate the role played by PGRN in the size of the choroidal neovascularization (CNV) in laser-induced CNV mice.

Methods

CNVs were induced in C57BL/6J mice by laser photocoagulation of the retina. The expression of PGRN and the accumulation of Iba-1⁺ cells around the sites of the CNVs were determined. Grn^-/-, Grn^+/-, and Grn^+/+ mice with laser-induced CNVs were also studied. To evaluate the effect of macrophages on the inflammation, we used a macrophage cell line (RAW264.7) in which the expression of PGRN was knocked down by RNA interference and peritoneal macrophages derived from Grn^-/- and Grn^+/+ mice. These cells were incubated under hypoxic conditions (1% O₂).

Results

Iba-1⁺ myeloid cells migrated and accumulated in the photocoagulation-induced CNV areas, and the CNV lesions secreted high levels of PGRN in Grn^+/+ mice. The size of the CNVs was larger in Grn^-/- mice than in Grn^+/- and Grn^+/+ mice. In Grn^-/- mice, the number of ocular-infiltrating Iba-1⁺ cells around the CNV was higher, and these cells produced more VEGF-A than the cells in the Grn^+/+ mice. PGRN-silencing of RAW264.7 cells led to abnormal activation of the cells. In addition, hypoxic conditions promoted the production of proangiogenic and proinflammatory cytokines from PGRN-deficient macrophages. Interestingly, the expression level of lysosome-associated proteins and the number of activated lysosomes increased in PGRN-deficient macrophages.

Conclusions

These findings indicate that PGRN deficiency in Iba-1⁺ cells activates the lysosomal function that then leads to abnormal inflammation. The aberrant activation of Iba-1⁺ myeloid cells might contribute to the progression of the CNV and the regulation of these cells might be a novel therapeutic target for exudative AMD.

SUBMITTER: Takahashi K

PROVIDER: S-EPMC8310601 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Age-related macular degeneration (AMD) is a complex, multifactorial, progressive disease which represents a leading cause of irreversible visual impairment and blindness in older individuals. Human cytomegalovirus (HCMV), which infects 50-80% of humans, is usually acquired during early life and persists in a latent state for the life of the individual. In view of its previously described pro-angiogenic properties, we hypothesized that cytomegalovirus might be a novel risk factor for progression to an advanced form, neovascular AMD, which is characterized by choroidal neovascularization (CNV). The purpose of this study was to investigate if latent ocular murine cytomegalovirus (MCMV) infection exacerbated the development of CNV in vascular endothelial growth factor (VEGF)-overexpressing VEGF-Ahyper mice. Here we show that neonatal infection with MCMV resulted in dissemination of virus to various organs throughout the body including the eye, where it localized principally to the choroid in both VEGF-overexpressingVEGF-Ahyper and wild-type(WT) 129 mice. By 6 months post-infection, no replicating virus was detected in eyes and extraocular tissues, although virus DNA was still present in all eyes and extraocular tissues of both VEGF-Ahyper and WT mice. Expression of MCMV immediate early (IE) 1 mRNA was detected only in latently infected eyes of VEGF-Ahyper mice, but not in eyes of WT mice. Significantly increased CNV was observed in eyes of MCMV-infected VEGF-Ahyper mice compared to eyes of uninfected VEGF-Ahyper mice, while no CNV lesions were observed in eyes of either infected or uninfected WT mice. Protein levels of several inflammatory/angiogenic factors, particularly VEGF and IL-6, were significantly higher in eyes of MCMV-infected VEGF-Ahyper mice, compared to uninfected controls. Initial studies of ocular tissue from human cadavers revealed that HCMV DNA was present in four choroid/retinal pigment epithelium samples from 24 cadavers. Taken together, our data suggest that ocular HCMV latency could be a significant risk factor for the development of AMD. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Project description:The aryl hydrocarbon receptor (AhR) is a heterodimeric transcriptional regulator with pleiotropic functions in xenobiotic metabolism and detoxification, vascular development and cancer. Herein, we report a previously undescribed role for the AhR signalling pathway in the pathogenesis of the wet, neovascular subtype of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly in the Western world. Comparative analysis of gene expression profiles of aged AhR(-/-) and wild-type (wt) mice, using high-throughput RNA sequencing, revealed differential modulation of genes belonging to several AMD-related pathogenic pathways, including inflammation, angiogenesis and extracellular matrix regulation. To investigate AhR regulation of these pathways in wet AMD, we experimentally induced choroidal neovascular lesions in AhR(-/-) mice and found that they measured significantly larger in area and volume compared to age-matched wt mice. Furthermore, these lesions displayed a higher number of ionized calcium-binding adaptor molecule 1-positive (Iba1(+) ) microglial cells and a greater amount of collagen type IV deposition, events also seen in human wet AMD pathology specimens. Consistent with our in vivo observations, AhR knock-down was sufficient to increase choroidal endothelial cell migration and tube formation in vitro. Moreover, AhR knock-down caused an increase in collagen type IV production and secretion in both retinal pigment epithelial (RPE) and choroidal endothelial cell cultures, increased expression of angiogenic and inflammatory molecules, including vascular endothelial growth factor A (VEGFA) and chemokine (C-C motif) ligand 2 (CCL2) in RPE cells, and increased expression of secreted phosphoprotein 1 (SPP1) and transforming growth factor-?1 (TGF?1) in choroidal endothelial cells. Collectively, our findings identify AhR as a regulator of multiple pathogenic pathways in experimentally induced choroidal neovascularization, findings that are consistent with a possible role of AhR in wet AMD. The data discussed in this paper have been deposited in NCBI's Gene Expression Omnibus; GEO Submission No. GSE56983, NCBI Tracking System No. 17021116.

Dataset Information

Progranulin deficiency in Iba-1⁺ myeloid cells exacerbates choroidal neovascularization by perturbation of lysosomal function and abnormal inflammation.

Background

Methods

Results

Conclusions

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OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Progranulin deficiency in Iba-1+ myeloid cells exacerbates choroidal neovascularization by perturbation of lysosomal function and abnormal inflammation.

Background

Methods

Results

Conclusions

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Progranulin deficiency in Iba-1⁺ myeloid cells exacerbates choroidal neovascularization by perturbation of lysosomal function and abnormal inflammation.