Targeting the SNAI1-LAMP3 axis to restore lysosomal function and alleviate autophagic flux impairment to delay retinal degeneration.

Role of ESCRT pathway and autophagy in neurodegenerative diseases.

WDR34 Deficiency Disrupts Retrograde Intraflagellar Transport and Induces Unfolded Protein Response-Driven Inflammation and Retinal Degeneration

Purpose Retinitis pigmentosa (RP) is a hereditary retinal disease characterized by progressive photoreceptor cell (PRC) degeneration. WD repeat domain 34 (WDR34), an intermediate chain of dynein-2, is essential for retrograde intraflagellar transport (IFT). However, the mechanisms by which WDR34 deficiency causes retinal degeneration remain unclear. This study aims to investigate the impact of WDR34 deficiency on retrograde IFT and its contribution to retinal degeneration. Methods WDR34 deficiency was modeled in vivo via subretinal injection of adeno-associated virus–shRNA–WDR34 and in vitro by CRISPR/Cas9-mediated knockout in 661W cells. Retinal degeneration and IFT defects were assessed by histologic, functional, and ultrastructural analyses. Proteomic analysis followed by in vivo validation was used to investigate the molecular mechanism underlying WDR34-deficient retinal degeneration. Results WDR34 knockdown induced progressive retinal degeneration characterized by PRC apoptosis, gradual outer nuclear layer thinning, reduced electroretinography responses, and outer segment shortening. WDR34 deficiency impaired retrograde IFT and caused rhodopsin and opsin mislocalization. These alterations induced endoplasmic reticulum stress and unfolded protein response (UPR) activation, activating the IRE1α/TRAF2/NF-κB signaling pathway, ultimately contributing to retinal inflammation and degeneration. Conclusions WDR34 is crucial for maintaining retrograde IFT in PRCs. WDR34 deficiency disrupts outer segment maintenance and triggers UPR-mediated inflammatory responses and apoptosis, ultimately leading to retinal degeneration. This study reveals a novel mechanistic link among WDR34, retrograde IFT, ciliopathies, and retinal degeneration, providing potential therapeutic insights for ciliopathy-associated RP.

Activation of ER stress mediated by HspB4/Cryaa reduction contributes to photoreceptor apoptosis in rd9 mouse model of X-linked Retinitis Pigmentosa

Results identify Cryaa as a critical regulator of ER stress and demonstrate that its reduction promotes UPR activation and subsequent photoreceptor apoptosis in the rd9 model, revealing a key role for Cryaa in XLRP pathology and may provide a novel therapeutic perspective for this disease.

Zinc-mediated lysosomal activation by 1H10 enhances autophagy and attenuates tau pathology in Alzheimer's disease models.

Impaired autophagic flux and lysosomal dysfunction contribute critically to the accumulation of pathological protein aggregates in Alzheimer's disease (AD). Emerging evidence suggests that intracellular zinc dynamics regulate lysosomal function by modulating processes such as acidification and lysosomal biogenesis. We previously identified 1H10 as an AMP-activated protein kinase (AMPK) inhibitor and subsequently demonstrated its zinc-binding capacity and ability to regulate intracellular zinc homeostasis. Building on our prior findings that intra-lysosomal zinc promotes acidification and activates transcription factor EB (TFEB), we investigated whether 1H10 enhances lysosomal function through zinc mobilization in neurons, thereby improving autophagy and reducing pathological protein accumulation. In primary cortical neurons, 1H10 increased lysosomal abundance and enhanced lysosomal degradative capacity in a zinc-dependent manner, as demonstrated by increased cathepsin B activity and DQ-BSA degradation. It alleviated lysosomal dysfunction induced by v-ATPase inhibition and promoted autophagic flux, leading to reduced accumulation of amyloid-β (Aβ) and tau in neuronal models. In 5XFAD mice, 1H10 treatment showed trends toward improved spatial learning in the Morris water maze, reduced tau phosphorylation at Thr205 and Ser214, normalized LC3-II levels, and restored autophagic-lysosomal homeostasis, without significant changes in extracellular amyloid plaque burden. These findings indicate that zinc-mediated lysosomal activation by 1H10 enhances the autophagy-lysosomal pathway and attenuates tau pathology in AD models, suggesting that targeting lysosomal function may represent a potential therapeutic strategy for neurodegenerative disorders characterized by impaired proteostasis.

Roles of autophagy in brain homeostasis and disease.

UCHL1 attenuates diabetic retinopathy by deubiquitinating and stabilizing NRF2 to suppress oxidative stress-induced retinal vascular endothelial ferroptosis.

Diabetic retinopathy (DR) is characterized by progressive retinal microvascular injury, with oxidative stress and ferroptosis increasingly recognized as key pathogenic contributors. This study investigated whether ubiquitin C-terminal hydrolase L1 (UCHL1) regulates retinal endothelial ferroptosis through stabilization of nuclear factor erythroid 2-related factor 2 (NRF2). Analysis of the GSE102485 dataset identified UCHL1 as a downregulated deubiquitinating enzyme in DR. Streptozotocin-induced type 1 diabetic mice and high glucose (HG)-induced human retinal capillary endothelial cells (HRCECs) were used, together with UCHL1 inhibition/knockdown, AAV-mediated UCHL1 overexpression, and NRF2 knockdown. UCHL1 expression was reduced in diabetic retinas and HG-induced HRCECs, accompanied by ferroptosis activation, mitochondrial injury, and endothelial dysfunction. Pharmacological inhibition or siRNA-mediated depletion of UCHL1 intensified oxidative stress, Fe2⁺ accumulation, lipid peroxidation, mitochondrial fragmentation, and cristae disruption, while impairing endothelial barrier integrity, migration, and tube formation. In vivo, LDN57444 aggravated retinal vascular leakage and fundus vascular abnormalities, whereas AAV-UCHL1 preserved retinal architecture and reduced vascular permeability. Mechanistically, co-immunoprecipitation and ubiquitination assays demonstrated that UCHL1 interacted with NRF2 and stabilized NRF2 by removing K48-linked polyubiquitin chains. Nuclear-cytoplasmic fractionation further showed that UCHL1 overexpression restored NRF2 abundance and increased nuclear NRF2 accumulation under HG conditions. Ferrostatin-1 rescued UCHL1 depletion-induced ferroptotic injury, whereas NRF2 knockdown abolished the protection conferred by UCHL1 overexpression. These findings highlight the UCHL1/NRF2 axis may represent a therapeutic target in DR.