title: Aluminum Activates PERK-EIF2α Signaling and Inflammatory Proteins in Human Neuroblastoma SH-SY5Y Cells.
abstract: Aluminum is the third most abundant element present in the earth's crust and human exposure to it is possible due to industrialization, utensils, medicines, antiperspirants, etc. Evidences suggest involvement of aluminum in a variety of neurodegenerative disorders including Alzheimer's disease. Endoplasmic reticulum (ER) stress has been implicated in various neurological disorders. ER stress may be a result of impaired calcium homeostasis due to perturbed redox balance and is known to elicit inflammation through the activation of unfolded protein response (UPR). In the present study, we aimed to investigate the role of aluminum in ER stress-mediated activation of inflammatory responses in neuroblastoma cells. Lactate dehydrogenase (LDH) release assay revealed that aluminum compromised the membrane integrity of neuroblastoma cells, probably due to membrane damage, as indicated by enhanced levels of lipid peroxidation (LPO). Besides this, our results clearly demonstrated elevated reactive oxygen species (ROS) levels and a weakened antioxidant defence system manifested by decrease in catalase (CAT) activity and cellular glutathione (GSH). Moreover, we studied the expression of key apoptosis-related proteins, ER stress-mediated activation of UPR, and its downstream inflammatory pathway. It was observed that aluminum potentially enhanced protein levels of PERK, EIF2α, caspase 9, caspase 3, and inflammatory markers like NF-κB, NLRP3, HMGB1, and nitric oxide (NO). Furthermore, aluminum altered TNFα, IL1β, IL6, and IL10 mRNA levels as well. The overall findings indicated that aluminum mediates UPR activation through ER stress, which results in induction of inflammatory pathway and apoptotic proteins in neuronal cells.
authors.affiliation: Department of Biochemistry and Forensic Medicine & Toxicology, King George's Medical University, Lucknow, 226003, Uttar Pradesh, India.
authors.forename: Syed Husain Mustafa
authors.initials: SHM
authors.lastname: Rizvi
authors.affiliation: Department of Biochemistry and Forensic Medicine & Toxicology, King George's Medical University, Lucknow, 226003, Uttar Pradesh, India.
authors.forename: Arshiya
authors.initials: A
authors.lastname: Parveen
authors.affiliation: Department of Biochemistry and Forensic Medicine & Toxicology, King George's Medical University, Lucknow, 226003, Uttar Pradesh, India.
authors.forename: Israr
authors.initials: I
authors.lastname: Ahmad
authors.affiliation: Fibre Toxicology Division, CSIR-Indian Institute of Toxicology Research, Lucknow, 226001, Uttar Pradesh, India.
authors.forename: Iqbal
authors.initials: I
authors.lastname: Ahmad
authors.affiliation: Department of Biochemistry and Forensic Medicine & Toxicology, King George's Medical University, Lucknow, 226003, Uttar Pradesh, India.
authors.forename: Anoop K
authors.initials: AK
authors.lastname: Verma
authors.affiliation: Department of Zoology, Lucknow University, Lucknow, 226001, Uttar Pradesh, India.
authors.forename: Md
authors.initials: M
authors.lastname: Arshad
authors.affiliation: Department of Biochemistry and Forensic Medicine & Toxicology, King George's Medical University, Lucknow, 226003, Uttar Pradesh, India. abbasalimahdi@gmail.com.
authors.forename: Abbas Ali
authors.initials: AA
authors.lastname: Mahdi
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology*; D009942:Organometallic Compounds / Q000494:pharmacology*; D011753:Pyrones / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured; D056811:Unfolded Protein Response / Q000187:drug effects; D019892:eIF-2 Kinase / Q000378:metabolism*
chemical_list: D016207:Cytokines; D015852:Eukaryotic Initiation Factor-2; D009942:Organometallic Compounds; D011753:Pyrones; D014157:Transcription Factors; C067527:aluminum maltolate; C460640:EIF2AK3 protein, human; D019892:eIF-2 Kinase
keywords: ER stress; Inflammation; Oxidative stress; Unfolded protein response