Mustard gas exposure instigates retinal Müller cell gliosis

• Published in: Experimental eye research Vol. 230; p. 109461
• Main Authors: Mahaling, Binapani, Sinha, Nishant R., Sokupa, Sibabalo, Addi, Utkarsh Reddy, Mohan, Rajiv R., Chaurasia, Shyam S.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2023
• Subjects: Antioxidants - pharmacology; Caspase 1; Caspases - metabolism; Cell death; Ependymoglial Cells - metabolism; Gliosis; Gliosis - etiology; Humans; Inflammasomes - metabolism; Mustard gas; Mustard Gas - toxicity; Müller glial cells; Nitrogen mustard; NLR Family, Pyrin Domain-Containing 3 Protein - metabolism; NLRP3; Oxidative stress; Pyroptosis; Retina; Sulfur mustard; DHE; Oxidative stress; MCP-1; COX-1; Retina; AO/Br; CWA; TUNEL; RNS; NLRP3; Caspase 1; SM; Müller glial cells; GPx-1; GSDMD; Pyroptosis; DCF; Sulfur mustard; GR; IL-8; IL-6; GFAP; MGK; GCLC; Gliosis; Txnrd-1; Mustard gas; Cell death; Nitrogen mustard; ROS; MnSOD; ERG; NM
• ISSN: 0014-4835; 1096-0007
• DOI: 10.1016/j.exer.2023.109461

Sulfur mustard (SM) is a chemical warfare agent (CWA) that causes severe eye pain, photophobia, excessive lacrimation, corneal and ocular surface defects, and blindness. However, SM's effects on retinal cells are relatively meager. This study investigated the role of SM toxicity on Müller glial cells responsible for cellular architecture, inner blood-retinal barrier maintenance, neurotransmitter recycling, neuronal survival, and retinal homeostasis. Müller glial cells (MIO-M1) were exposed to SM analog, nitrogen mustard (NM), at varying concentrations (50–500 μM) for 3 h, 24 h, and 72 h. Müller cell gliosis was evaluated using morphological, cellular, and biochemical methods. Real-time cellular integrity and morphological evaluation were performed using the xCELLigence real-time monitoring system. Cellular viability and toxicity were measured using TUNEL and PrestoBlue assays. Müller glia hyperactivity was calculated based on glial fibrillary acidic protein (GFAP) and vimentin immunostaining. Intracellular oxidative stress was measured using DCFDA and DHE cell-based assays. Inflammatory markers and antioxidant enzyme levels were determined by quantitative real-time PCR (qRT-PCR). AO/Br and DAPI staining further evaluated DNA damage, apoptosis, necrosis, and cell death. Inflammasome-associated Caspase-1, ASC, and NLRP3 were studied to identify mechanistic insights into NM toxicity in Müller glial cells. The cellular and morphological evaluation revealed the Müller glia hyperactivity after NM exposure in a dose- and time-dependent manner. NM exposure caused significant oxidative stress and enhanced cell death at 72 h. A significant increase in antioxidant indices was observed at the lower concentrations of NM. Mechanistically, we found that NM-treated MIO-M1 cells increased caspase-1 levels that activated NLRP3 inflammasome-induced production of IL-1β and IL-18, and elevated Gasdermin D (GSDMD) expression, a crucial component actuating pyroptosis. In conclusion, NM-induced Müller cell gliosis via increased oxidative stress results in caspase-1-dependent activation of the NLRP3 inflammasome and cell death driven primarily by pyroptosis. •Nitrogen mustard (NM) causes dose- and time-dependent cellular abnormalities in human Müller glia.•NM induced oxidative stress, lipid peroxidation and nitrotyrosine expression, in Müller glia.•NM causes Müller gliosis via caspase-1-dependent NLRP3 inflammasome activation and cell death primarily by pyroptosis.•This study unveils new mechanistic understanding for mustard gas exposure to the retinal Müller glia.