Betulinic Acid Exerts Cytoprotective Activity on Zika Virus-Infected Neural Progenitor Cells

Bruno R R Cavalcante,Vinícius P C Rocha,Carolina K V Nonaka,Juliana P B Menezes,Kyan J Allahdadi,Milena B P Soares,Moisés S Oliveira,José M Barbosa-Filho,Laisla R Peixoto,Erik A Rossi,Gabriele L S Martins,Bruno D Paredes,Beatriz R S Dias,Silvia I Sardi,Gúbio S Campos,Gabriela L A Sampaio,Luciana S Aragão-França,Bruno S F Souza

doi:10.3389/fcimb.2020.558324

Abstract

Zika virus (ZIKV), a member of the Flaviviridae family, was brought into the spotlight due to its widespread and increased pathogenicity, including Guillain-Barré syndrome and microcephaly. Neural progenitor cells (NPCs), which are multipotent cells capable of differentiating into the major neural phenotypes, are very susceptible to ZIKV infection. Given the complications of ZIKV infection and potential harm to public health, effective treatment options are urgently needed. Betulinic acid (BA), an abundant terpenoid of the lupane group, displays several biological activities, including neuroprotective effects. Here we demonstrate that Sox2+ NPCs, which are highly susceptible to ZIKV when compared to their neuronal counterparts, are protected against ZIKV-induced cell death when treated with BA. Similarly, the population of Sox2+ and Casp3+ NPCs found in ZIKV-infected cerebral organoids was significantly higher in the presence of BA than in untreated controls. Moreover, well-preserved structures were found in BA-treated organoids in contrast to ZIKV-infected controls. Bioinformatics analysis indicated Akt pathway activation by BA treatment. This was confirmed by phosphorylated Akt analysis, both in BA-treated NPCs and brain organoids, as shown by immunoblotting and immunofluorescence analyses, respectively. Taken together, these data suggest a neuroprotective role of BA in ZIKV-infected NPCs.

Highlights

Zika virus (ZIKV) is a positive-sense single-stranded RNA arbovirus that belongs to the genus Flavivirus of the Flaviviridae family, which comprises other members that cause widespread morbidity worldwide (Huang et al, 2014), such as dengue virus (DENV), West Nile virus (WNV), yellow fever virus (YFV), and Japanese encephalitis virus (JEV) (Song et al, 2017)
In this work we aimed to evaluate the role of betulinic acid regarding its anti-ZIKV and neuroprotective activities in human neural progenitor cells, in both 2D and 3D cultures
To further corroborate the fact that lower concentrations of Betulinic acid (BA) protect neural progenitor cells (NPCs) cultures from ZIKV-induced cell death, we evaluated the expression of cleaved caspase 3 after BA treatment in NPCs after

Summary

Introduction

Zika virus (ZIKV) is a positive-sense single-stranded RNA arbovirus that belongs to the genus Flavivirus of the Flaviviridae family, which comprises other members that cause widespread morbidity worldwide (Huang et al, 2014), such as dengue virus (DENV), West Nile virus (WNV), yellow fever virus (YFV), and Japanese encephalitis virus (JEV) (Song et al, 2017). ZIKV infection had been thought to be a prominent disease, it has been underestimated for many years since the human infection was first. ZIKV has the ability to infect neural progenitor cells (NPCs), resulting in alterations in the expression of cell cycle-related proteins, induction of apoptosis and impaired production of new neurons (Li H. et al, 2016; Souza et al, 2016). Sox2+ NPCs population has been reported as highly affected by ZIKV (Souza et al, 2016). The function of the neural circuitry can be drastically affected by variations in the number of neural cells produced during development, whether caused by disease or infection. In vitro ZIKV infection of 3D cultures of human neurospheres compromised their growth and led to increased cell death (Garcez et al, 2016)

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