The role of thioredoxin-interacting protein in corticosterone induced damage in astrocytes

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dc.contributor.authorAcharya, Sushank
dc.contributor.examiningcommitteeKatyal, Sachin (Pharmacology and Therapeutics)
dc.contributor.examiningcommitteeEftekharpour, Eftekhar (Physiology and Pathophysiology)
dc.contributor.supervisorWang, Jun-Feng
dc.date.accessioned2024-08-26T16:45:20Z
dc.date.available2024-08-26T16:45:20Z
dc.date.issued2024-08-23
dc.date.submitted2024-08-19T20:48:37Zen_US
dc.date.submitted2024-08-23T15:57:58Zen_US
dc.degree.disciplinePharmacology and Therapeutics
dc.degree.levelMaster of Science (M.Sc.)
dc.description.abstractBackground: Chronic treatment with corticosterone (CORT) can induce oxidative stress and neuroinflammation. Thioredoxin-interacting protein (Txnip) inhibits antioxidant protein thioredoxin, interrupting protein thiol reduction and inducing oxidative stress. Txnip can also bind to NLRP3, facilitating NLRP3 inflammasome forming, activating caspase-1 and releasing IL-1β. Previously, our laboratory found that chronic CORT treatment increased Txnip levels in cultured mouse neurons and microglia, suggesting that CORT may upregulate Txnip, inhibiting thioredoxin activity and activating NLRP3 inflammasome, which may amplify oxidative stress and neuroinflammation. Objective: Since astrocytes can release proinflammatory cytokines and reactive oxygen species, facilitating oxidative stress and neuroinflammatory processes. The objective of this study is to determine if CORT treatment can upregulate Txnip in astrocytes, further promoting oxidative stress and inflammation. Methods: Primary cultured mouse astrocytes were used in the present study. Thioredoxin and Txnip protein levels were measured by immunoblotting assay. Eosin-labeled insulin was used as a substrate for measuring thioredoxin activity. Total reduced thiol level was measured using Ellman’s assay. Protein sulfenylation and carbonylation were measured by dimedone conjugation and biotin-hydrazide conjugation methods respectively. NLRP3/Txnip binding was measured by co-immunoprecipitation assay. Fluorogenic Z-YVAD-AFC was used as a substrate for measuring caspase-1 activity, while IL-1β release was measured by enzyme-linked immunosorbent assay. Crispr/Cas9/Txnip sgRNA was used to knock out Txnip gene. Results: We found that CORT treatment for 24 hours had no effect on thioredoxin levels, but increased Txnip levels. CORT-increased Txnip levels were decreased by mineralocorticoid receptor antagonist spironolactone and glucocorticoid receptor antagonist RU486. CORT treatment decreased thioredoxin activity, but had no effects on total reduced thiol levels, sulfenylated protein levels and carbonylated protein levels. However, CORT treatment increased Txnip/NLRP3 binding activity, caspase-1 activity and IL-1β release. Txnip knockout attenuated CORT-increased caspase-1 activity and IL-1β release. Conclusion: The findings suggest that CORT treatment increases Txnip level, which could promote NLRP3 activity, activate caspase-1 and release IL-1β to facilitate neuroinflammatory process in astrocytes. However, due to enriched antioxidants in astrocytes, CORT-increased Txnip may not be sufficient to exert oxidative stress.
dc.description.noteOctober 2024
dc.identifier.urihttp://hdl.handle.net/1993/38425
dc.language.isoeng
dc.rightsopen accessen_US
dc.subjectcorticosterone
dc.subjectastrocytes
dc.subjectdepression
dc.subjectthioredoxin-interacting protein
dc.subjectthioredoxin
dc.subjectoxidative stress
dc.subjectinflammation
dc.titleThe role of thioredoxin-interacting protein in corticosterone induced damage in astrocytes
dc.typemaster thesisen_US
local.subject.manitobano
oaire.awardNumberRGPIN-2020-05400
oaire.awardTitleThe role of thioredoxin system in regulation of synaptic development and neurotransmission in the central nervous system
project.funder.identifierhttps://doi.org/10.13039/501100000038
project.funder.nameNatural Sciences and Engineering Research Council of Canada
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