Regulation of peroxiredoxin-3 gene expression under basal and hyperglycemic conditions: Key roles for transcription factors Sp1, CREB and NF-κB

• Published in: Biochimica et biophysica acta. Molecular basis of disease 2023-06, Vol.1869 (5), p.166691-166691, Article 166691
• Main Authors: Arkat, Silpa, Poovitha, Sundar, Vijayakumar, Anupama, Dhat, Rohini, Sitasawad, Sandhya L., Mahapatra, Nitish R.
• Format: Article
• Language: English
• Subjects: Animals; Cyclic AMP Response Element-Binding Protein - genetics; Cyclic AMP Response Element-Binding Protein - metabolism; Diabetes Mellitus, Experimental - genetics; Diabetic cardiomyopathy; Gene Expression; Gene regulation; Heart; Mitochondria; NF-kappa B - genetics; NF-kappa B - metabolism; Peroxiredoxin III - genetics; Peroxiredoxin-3; Rats; RNA, Messenger - metabolism; Sp1 Transcription Factor; Streptozotocin
• ISSN: 0925-4439; 1879-260X
• DOI: 10.1016/j.bbadis.2023.166691

Peroxiredoxin-3 (Prx-3), a thioredoxin-dependent peroxidase located exclusively in the mitochondrial matrix, catalyses peroxides/peroxinitrites. Altered levels of Prx-3 is associated with diabetic cardiomyopathy (DCM). However, molecular mechanisms of Prx-3 gene regulation remain partially understood. We undertook a systemic analysis of the Prx-3 gene to identify the key motifs and transcriptional regulatory molecules. Transfection of promoter-reporter constructs in the cultured cells identified −191/+20 bp domain as the core promoter region. Stringent in silico analysis of this core promoter revealed putative binding sites for specificity protein 1 (Sp1), cAMP response element–binding protein (CREB) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Interestingly, while co-transfection of the −191/+20 bp construct with Sp1/CREB plasmid diminished Prx3 promoter-reporter activity, mRNA and protein levels, co-transfection with NF-κB expression plasmid augmented the same. Consistently, inhibition of Sp1/CREB/NF-κB expression reversed the promoter-reporter activity, mRNA and protein levels of Prx-3, thereby confirming their regulatory effects. ChIP assays provided evidence for interactions of Sp1/CREB/NF-κB with the Prx-3 promoter. H9c2 cells treated with high glucose as well as streptozotocin (STZ)-treated diabetic rats showed time-dependent reduction in promoter activity, endogenous transcript and protein levels of Prx-3. Augmentation of Sp1/CREB protein levels and their strong binding with Prx-3 promoter are responsible for diminished Prx-3 levels under hyperglycemia. The activation/increase in the NF-κB expression under hyperglycemia was not sufficient to restore the reduction of endogenous Prx-3 levels owing to its weak binding affinity. Taken together, this study elucidates the previously unknown roles of Sp1/CREB/NF-κB in regulating Prx-3 gene expression under hyperglycemic condition. [Display omitted] •Sp1 and CREB act as transcriptional repressors for Prx-3 gene expression.•NF-κB acts as an activator of Prx-3 gene expression.•Sp1 and CREB down-regulate Prx-3 gene expression under hyperglycemia.