Journal of Aquaculture Research & Development

Abstract

Role of PmRab7 Regulation in WSSV Infection and Functional Validation of Small Molecule as PmRab7 GTPase Inhibitor

Amrendra Kumar, Sudhanshu Shekhar and Saravanakumar A

White Spot Syndrome (WSS) is a viral disease has extensive threatened the shrimp farming industries. It is caused by White spot syndrome baculovirus (WSSB). The shrimps (P. monodon and L. vannamei) are unable to defend themselves by “nonself” materials and pathogen, due to less define adaptive immune response. Therefore, the present work was taken on priority to study the regulation of PmRab7 transcript, which might be a receptor for WSSV (vP28) after implication of small molecule inhibitor. Total 70 GTPase small molecules were screened initially, against the 3D structure of PmRab7. Among all, the CID 1067700 molecule was selected for molecular docking (IFD) with PmRab7 in presence of GTP, GDP and Mg++. Furthermore, a small molecule was fed in feed formulation to P. monodon and transcriptional regulation of PmRab7 was relatively quantified against IFN-α as housekeeping genes during the WSSV infection. Herein we identified a PmRab7 inhibitor, CID 1067700, by targeting DNA binding domain of PmRab7 using virtual screening strategy. CID 1067700 preferentially suppresses GTPase activity to alter GTP and Mg++ from their positions. Furthermore, CID 1067700 inhibits expression of PmRab7 downstream target genes thus CID 1067700 represent novel probes for the development of specific inhibitors targeting DNA binding domain of PmRab7 and a potential therapeutic against WSSV. Substantial changes were observed in PmRab7 regulation and WSSV multiplication in the initial trial of CID 106700. CID 106700 leads towards successful inactivation of PmRab7 by altering the GTP and Mg++ from their native positions. The PmRab7 regulation was increased 5 to 8-fold during 72 hrs of infection. GTP replacement by small molecules has revealed significantly down regulation of PmRab7 gene during WSSV infection. Remarkably, the viral load (absolutely quantified) also has been found to be reduced when the PmRab7 was down-regulated. WSSV internalization has directly linked with regulation of PmRab7.