Project description:Glaucoma is a group of diseases that results in the death of retinal ganglion cells (RGCs), leading to permanent blindness. Myocilin is one of the genetic factors associated with primary open angle glaucoma (POAG) with or without ocular hypertension. Using myocilin-dependent POAG patient-derived iPSC RGCs, we have shown that RGCs harboring the myocilin mutation (A445V) have dysregulated unfolded protein response with developmental and functional abnormalities, which may make them suscepetible to degeneration regardless of ocular hypertension.
Project description:Glaucoma leads to vision loss due to retinal ganglion cell death. Astrocyte reactivity contributes to neurodegeneration. Our recent study found that lipoxin B4 (LXB4), produced by retinal astrocytes, has direct neuroprotective actions on retinal ganglion cells. In this study, we aimed to investigate how the autacoid LXB4 influences astrocyte reactivity in the retina under inflammatory cytokine-induced activation and ocular hypertension conditions. The protective activity of LXB4 was investigatedin vivousing the mouse silicone-oil model of chronic ocular hypertension (n=40). By employing a range of analytical techniques, including bulk RNA-seq, RNAscope in-situhybridization, qPCR, and lipidomic analyses, we discovered the formation of neuroprotective lipoxins in rodents (including the retina and optic nerve), primates (optic nerve), and human brain astrocytes, indicating their presence across various species. Our findings in the mouse retina demonstrated significant dysregulation of the lipoxin pathway in response to chronic ocular hypertension, leading to an increase in 5-lipoxygenase (5-LOX) activity and a decrease in 15-lipoxygenase activity. This dysregulation was coincident with a marked upregulation of astrocyte reactivity. Reactive human brain astrocytes also showed a significant increase in 5-LOX. Administration of LXB4 regulated the lipoxin pathway, restored and amplified LXA4 generation (another lipoxin with distinct bioactions), and mitigated astrocyte reactivity in mouse retinas and human brain astrocytes. In conclusion, the lipoxin pathway is functionally expressed in rodents, primates, and human astrocytes, and is a resident neuroprotective pathway that is downregulated in reactive astrocytes. Novel cellular targets for LXB4’s neuroprotective action are inhibition of astrocyte reactivity and restoration of lipoxin generation. Amplifying the lipoxin pathway is a potential target to disrupt or prevent astrocyte reactivity in neurodegenerative diseases.
Project description:Chronic ocular pathologies such as cataracts and glaucoma are emerging as an important problem for public health due to the changes in lifestyle and longevity. These age-related ocular diseases are largely mediated by oxidative stress. Small extracellular vesicles (sEVs) are involved in cell-to-cell communication and transport. There is an increasing interest about the function of small extracellular vesicles (sEVs) in the eye. However, the proteome content and characterization of sEVs released by ocular cells under pathological conditions are not yet well known. Here, we aimed to analyze the protein profile of sEVs and intracellular protein content from two ocular cell lines (lens epithelial cells and retinal ganglion cells) exposed to oxidative stress to identify altered proteins that could serve as potential diagnostic biomarkers. The protein content was analyzed by quantitative mass spectrometry-based proteomics. Validation was performed by WB and ELISA using cell extracts and aqueous humor from cataract and glaucoma patients. After data analysis, 176 and 7 dysregulated proteins with an expression ratio≥1.5 were identified in lens epithelial cells’ protein extract and sEVs, respectively, upon oxidative stress induction. In retinal ganglion cells, oxidative stress induction resulted in the dysregulation of 1033 proteins in cell extracts and 9 proteins in sEVs. In addition, by WB and ELISA, the dysregulation of proteins was mostly confirmed in aqueous humor samples from cataract or glaucoma patients in comparison to ICL individuals, with RAD23B showing high glaucoma diagnostic ability. Importantly, this work expands the knowledge of the proteome characterization of cataracts and glaucoma and provides new potential diagnostic glaucoma biomarkers.
Project description:Experimental ocular hypertension (IOP) induces senescence of retinal ganglion cells (RGCs) that mimicks events occurring in human glaucoma. An established transgenic p16-3MR mouse model in which the systemic administration of the small molecule ganciclovir (GCV) selectively kills p16INK4a-expressing cells was used to compare transcriptomes of retinas from IOP and control eyes in GCV-treated and non-treated mice, to investigate how experimental removal of senescent p16INK4a-positive cells impacts retinal cells in conditions resembling glaucoma.
Project description:Knee osteoarthritis (KOA), as a degenerative multifactorial disease, affects the quality of life and mental health of patients, and also brings a huge socioeconomic burden. Treating synovitis have shown promise as anti-inflammatory therapeutics in mitigating OA symptoms and disease progression. Here, by analysing synovial single-cell sequencing (scRNA-seq) data from KOA, we found that synovial fibroblasts (FLS) in OA synovium showed a distinct pro-inflammatory phenotype. We collected synovial tissue from patients with clinical OA as well as from healthy donors, and histological examination was consistent with findings in scRNA-seq. Inspired by recent cross-tissue fibroblast lineage studies, we identified by sequencing that healthy FLS in synovial tissues share transcriptome-level similarities with dermal fibroblasts (DFb). Subsequently, we revealed the local as well as systemic distribution of intra-articular injected DFbs by constructing/extracting two types of rat fibroblasts (luciferase DFbs as well as GFP DFbs). The results demonstrate that DFbs can be locally retained in the synovium for up to three weeks following targeted engrafting on it. And intra-articular injection does not result in DFbs migration to vital organs or the occurrence of histological changes in these organs. A rat model of KOA was constructed by anterior cruciate ligament transection (ACLT) in order to study the therapeutic effect of DFbs on KOA. After injection, the rats showed improvement in painful gait. In addition, histological as well as imaging results showed reduced synovitis and improvement in articular cartilage. Finally we verified the protective effect of DFbs on cytokine-stimulated chondrocytes in a co-culture system.