Increased LCN2 (lipocalin 2) in the RPE decreases autophagy and activates inflammasome-ferroptosis processes in a mouse model of dry AMD

Gupta, Urvi; Ghosh, Sayan; Wallace, Callen T.; Shang, Peng; Xin, Ying; Nair, Archana Padmanabhan; Yazdankhah, Meysam; Strizhakova, Anastasia; Ross, Mark A.; Liu, Haitao; Hose, Stacey; Stepicheva, Nadezda A.; Chowdhury, Olivia; Nemani, Mihir; Maddipatla, Vishnu; Grebe, Rhonda; Das, Manjula; Lathrop, Kira L.; Sahel, José‐Alain; Zigler, J. Samuel; Qian, Jiang; Ghosh, Arkasubhra; Sergeev, Yuri V.; Handa, James T.; Croix, Claudette M. St.; Sinha, Debasish

doi:10.1080/15548627.2022.2062887

Cited by 49 publications

(22 citation statements)

References 93 publications

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“…RPE explants from 10 month old WT, Cryba1 KO and Akt2 KI mice were cultured as explained previously [ 23 ]. Briefly, fresh eyes were enucleated, and the anterior segment was removed.…”

Section: Methodsmentioning

confidence: 99%

“…The SRS (including RPE-choroid) was dissected following perfusion to remove immune cells from choroid blood vessels as described previously [ 23 ]. The tissues were then digested with 0.05% collagenase D (Roche, Switzerland, Cat# 11088858001) at 37 °C for 30 min, teased out with a blunt end forceps and pipetted 10 times to release the cells.…”

Section: Methodsmentioning

confidence: 99%

“…The SRS (including RPE-choroid) was dissected following perfusion to remove immune cells from choroid blood vessels as described previously [ 23 ] from 15 month old Cryba1 -floxed and cKO mice. The single cell suspension was subjected to scRNAseq as a paid service from the Genomics Research Core of University of Pittsburgh to identify the RNA expression profile of different cells.…”

Section: Methodsmentioning

confidence: 99%

“…Bioinformatics analysis was performed by creating Seurat objects for each sample by the function “CreateSeuratObject” in Seurat package and then filtering out cells with nFeature_RNA > 8000, nFeature_RNA < 250, nUMI > 40,000, nUMI < 500, log10 (GenesPerUMI) < 0.8, or with a mitochondrial rate > 20%. Scrublet was used to remove predicted doublets with default parameters [ 23 ]. Then genes detected in fewer than 5 cells were also removed.…”

Section: Methodsmentioning

confidence: 99%

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Microglia–Neutrophil Interactions Drive Dry AMD-like Pathology in a Mouse Model

Boyce

Xin²,

Chowdhury

et al. 2022

Cells

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In dry age-related macular degeneration (AMD), inflammation plays a key role in disease pathogenesis. Innate immune cells such as microglia and neutrophils infiltrate the sub-retinal space (SRS) to induce chronic inflammation and AMD progression. But a major gap in our understanding is how these cells interact with each other in AMD. Here, we report a novel concept of how dynamic interactions between microglia and neutrophils contribute to AMD pathology. Using well-characterized genetically engineered mouse models as tools, we show that in the diseased state, retinal pigmented epithelial (RPE) cells trigger pro-inflammatory (M1) transition in microglia with diminished expression of the homeostatic marker, CX3CR1. Activated microglia localize to the SRS and regulate local neutrophil function, triggering their activation and thereby inducing early RPE changes. Ligand receptor (LR)-loop analysis and cell culture studies revealed that M1 microglia also induce the expression of neutrophil adhesion mediators (integrin β1/α4) through their interaction with CD14 on microglia. Furthermore, microglia-induced neutrophil activation and subsequent neutrophil-mediated RPE alterations were mitigated by inhibiting Akt2 in microglia. These results suggest that the Akt2 pathway in microglia drives M1 microglia-mediated neutrophil activation, thereby triggering early RPE degeneration and is a novel therapeutic target for early AMD, a stage without treatment options.

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“…RPE explants from 10 month old WT, Cryba1 KO and Akt2 KI mice were cultured as explained previously [ 23 ]. Briefly, fresh eyes were enucleated, and the anterior segment was removed.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Microglia–Neutrophil Interactions Drive Dry AMD-like Pathology in a Mouse Model

Boyce

Xin²,

Chowdhury

et al. 2022

Cells

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“…Lipocalins are a family of secreted adipokines that play an important role in various biological processes, and their accumulation results in mitochondrial dysfunction ( 6 ). Lipoprotein accumulation orchestrates a pro-inflammatory environment around the RPE ( 7 ). It increases inflammasome activation, cell apoptosis, and oxidative stress responses, eventually leading to AMD ( 5 ).…”

Section: Introductionmentioning

confidence: 99%

Regulator of G-protein signaling 1 promotes choroidal neovascularization in age-related macular degeneration

Zhang¹,

Zhang²,

Guo³

et al. 2022

Ann Transl Med

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Background: Age-related macular degeneration (AMD) is the leading cause of blindness, and is associated with oxidative stress and the development of new blood vessels. At present, the main clinical treatment for AMD includes intraocular injection of vascular endothelial growth factor (VEGF). However, treatment includes repeated injections with significant side-effects. Therefore, new treatment options are required. The aim of the present study was to discover the new treatment target of AMD from the gene level. Methods: The Gene Expression Omnibus (GEO) database was used to analyze the differential gene expression in AMD, and the regulator of G-protein signaling 1 (RGS1) was obtained by bioassay. Western blotting and quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used to detect the expression levels of RGS1, VEGF, and other related molecules in human microvascular endothelial cells (HMECs) under different conditions. Cell viability, apoptosis, and proliferation of HMECs were measured by Cell Counting Kit-8 proliferation assay. Immunofluorescence and immunohistochemistry detected the interaction between RGS1, platelet endothelial cell adhesion molecule-1, and VEGF. Results: RGS1 was found to closely associated with the proliferation of vascular endothelial cells, and therefore, with angiogenesis. The expression of RGS1, VEGF, and platelet endothelial cell adhesion molecule-1 was upregulated in laser model mice and hypoxia model HMECs. Knockout of RGS1 inhibits the expression of VEGF and HMEC proliferation, thereby inhibiting AMD angiogenesis. Conclusions: Our results support the use of RGS1 as a new potential target for the future treatment of AMD.

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