Effects of human Parvovirus B19 and Bocavirus VP1 unique region on tight junction of human airway epithelial A549 cells.

Chun-Ching Chiu,Bor-Show Tzang,Tsai-Ching Hsu,Ya-Fang Shi,Yuan-Chao Hsiao,Jiann-Jou Yang,Krzysztof Pyrc

doi:10.1371/journal.pone.0107970

Chun-Ching Chiu, Bor-Show Tzang + Show 5 more

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https://doi.org/10.1371/journal.pone.0107970

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Abstract

As is widely recognized, human parvovirus B19 (B19) and human bocavirus (HBoV) are important human pathogens. Obviously, both VP1 unique region (VP1u) of B19 and HBoV exhibit the secreted phospholipase A2 (sPLA2)-like enzymatic activity and are recognized to participate in the pathogenesis of lower respiratory tract illnesses. However, exactly how, both VP1u from B19 and HBoV affect tight junction has seldom been addressed. Therefore, this study investigates how B19-VP1u and HBoV-VP1u may affect the tight junction of the airway epithelial A549 cells by examining phospholipase A2 activity and transepithelial electrical resistance (TEER) as well as performing immunoblotting analyses. Experimental results indicate that TEER is more significantly decreased in A549 cells by treatment with TNF-α (10 ng), two dosages of B19-VP1u and BoV-VP1u (400 ng and 4000 ng) or bee venom PLA2 (10 ng) than that of the control. Accordingly, more significantly increased claudin-1 and decreased occludin are detected in A549 cells by treatment with TNF-α or both dosages of HBoV-VP1u than that of the control. Additionally, more significantly decreased Na+/K+ ATPase is observed in A549 cells by treatment with TNF-α, high dosage of B19-VP1u or both dosages of BoV-VP1u than that of the control. Above findings suggest that HBoV-VP1u rather than B19 VP1u likely plays more important roles in the disruption of tight junction in the airway tract. Meanwhile, this discrepancy appears not to be associated with the secreted phospholipase A2 (sPLA2)-like enzymatic activity.

Highlights

Human parvovirus B19 (B19) is a significant human pathogen that belongs to the Parvoviridae family [1]
This study attempted to confirm whether B19-VP1 unique region (VP1u) and human bocavirus (HBoV)-VP1u proteins have the phospholipase A2 (PLA2) activity by constructing and purifying the recombinant B19VP1u and HBoV-VP1u proteins, as described in the Materials and Methods Section, in order to analyze the secreted phospholipase A2 (sPLA2) activity
Significant PLA2 activity was detected in both recombinant B19-VP1u and HBoV-VP1u proteins with a PLA2 activity of 0.03560.002 mmol/min/mL and 0.06560.005 mmol/min/mL, respectively

Summary

Introduction

Human parvovirus B19 (B19) is a significant human pathogen that belongs to the Parvoviridae family [1]. As the pathogen of the fifth disease, B19 is more frequently associated with hematological symptoms and arthropathy, leading to severe diseases during pregnancy [3,4,5]. Implicated as a trigger of various autoimmune diseases [6,7], the B19 virus occasionally occurs in the respiratory tract [3,4,5]. The phospholipase A2 (PLA2)-like activity of B19-VP1u has been identified [8] and associated with its infectivity and pathogenesis of various diseases [9,10,11,12]

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