Punicalagin, an active pomegranate component, is a new inhibitor of PDIA3 reductase activity

Flavia Giamogante; Ilaria Marrocco; Laura Cervoni; Margherita Eufemi; Silvia Chichiarelli; Fabio Altieri

doi:10.1016/j.biochi.2018.01.008

Punicalagin, an active pomegranate component, is a new inhibitor of PDIA3 reductase activity

Biochimie. 2018 Apr:147:122-129. doi: 10.1016/j.biochi.2018.01.008. Epub 2018 Feb 6.

Authors

Flavia Giamogante¹, Ilaria Marrocco¹, Laura Cervoni¹, Margherita Eufemi¹, Silvia Chichiarelli¹, Fabio Altieri²

Affiliations

¹ Department of Biochemical Sciences, "A. Rossi Fanelli" and Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University, P.le A. Moro 5, 00185, Rome, Italy.
² Department of Biochemical Sciences, "A. Rossi Fanelli" and Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University, P.le A. Moro 5, 00185, Rome, Italy. Electronic address: fabio.altieri@uniroma1.it.

PMID: 29425676
DOI: 10.1016/j.biochi.2018.01.008

Abstract

Background: Polyphenolic compounds isolated from pomegranate fruit possess several pharmacological activities including anti-inflammatory, hepatoprotective, antigenotoxic and anticoagulant activities. The present work focuses the attention on PDIA3 interaction with punicalagin and ellagic acid, the most predominant components of pomegranate extracts. PDIA3, a member of the protein disulfide isomerase family involved in several cellular functions, is associated with different human diseases and it has the potential to be a pharmacological target.

Methods: The interaction of polyphenols with PDIA3 purified protein was explored by fluorescence quenching and calorimetric techniques and their effect on PDIA3 activity was investigated.

Results: A higher affinity was observed for punicalagin which also strongly affects PDIA3 reductase activity in vitro as a non-competitive inhibitor. Isothermal titration calorimetry confirmed the high affinity of punicalagin for PDIA3. Considering the PDIA3 involvement in oxidative cellular stress response observed in neuroblastoma cells after treatment with hydrogen peroxide, a comparative study was conducted to evaluate the effect of punicalagin on wild type and PDIA3-silenced cells. Punicalagin increases the cell sensitivity to hydrogen peroxide in neuroblastoma cells, but this effect is drastically reduced in PDIA3-silenced cells treated in the same experimental conditions.

Conclusions: Punicalagin binds PDIA3 and inhibits its redox activity. Comparative experiments conducted on unsilenced and PDIA3-silenced neuroblastoma cells suggest the potential of punicalagin to modulate PDIA3 reductase activity also in a biological model.

General significance: Punicalagin can be used as a new PDIA3 inhibitor and this can provide information on the molecular mechanisms underlying the biological activities of PDIA3 and punicalagin.

Keywords: Ligand-protein binding; Oxidative stress; PDIA3 inhibitor; PDIA3/ERp57; Pomegranate extracts; Punicalagin.

MeSH terms

Cell Line, Tumor
Enzyme Inhibitors / pharmacology*
Humans
Hydrogen Peroxide / pharmacology
Hydrolyzable Tannins / pharmacology*
Lythraceae / chemistry*
Protein Disulfide-Isomerases / antagonists & inhibitors*
Protein Disulfide-Isomerases / metabolism

Substances

Enzyme Inhibitors
Hydrolyzable Tannins
punicalagin
Hydrogen Peroxide
Protein Disulfide-Isomerases
PDIA3 protein, human