SARS-CoV-2 Infected Pediatric Cerebral Cortical Neurons: Transcriptomic Analysis and Potential Role of Toll-like Receptors in Pathogenesis.

Agnese Gugliandolo,Gianvincenzo Zuccotti,Placido Bramanti,Gloria Pelizzo,Luigi Chiricosta,Gioia Cappelletti,Stephana Carelli,Valeria Calcaterra,Emanuela Mazzon,Maria Antonietta Avanzini,Mara Biasin

doi:10.3390/ijms22158059

Abstract

Different mechanisms were proposed as responsible for COVID-19 neurological symptoms but a clear one has not been established yet. In this work we aimed to study SARS-CoV-2 capacity to infect pediatric human cortical neuronal HCN-2 cells, studying the changes in the transcriptomic profile by next generation sequencing. SARS-CoV-2 was able to replicate in HCN-2 cells, that did not express ACE2, confirmed also with Western blot, and TMPRSS2. Looking for pattern recognition receptor expression, we found the deregulation of scavenger receptors, such as SR-B1, and the downregulation of genes encoding for Nod-like receptors. On the other hand, TLR1, TLR4 and TLR6 encoding for Toll-like receptors (TLRs) were upregulated. We also found the upregulation of genes encoding for ERK, JNK, NF-κB and Caspase 8 in our transcriptomic analysis. Regarding the expression of known receptors for viral RNA, only RIG-1 showed an increased expression; downstream RIG-1, the genes encoding for TRAF3, IKKε and IRF3 were downregulated. We also found the upregulation of genes encoding for chemokines and accordingly we found an increase in cytokine/chemokine levels in the medium. According to our results, it is possible to speculate that additionally to ACE2 and TMPRSS2, also other receptors may interact with SARS-CoV-2 proteins and mediate its entry or pathogenesis in pediatric cortical neurons infected with SARS-CoV-2. In particular, TLRs signaling could be crucial for the neurological involvement related to SARS-CoV-2 infection.

Highlights

COVID-19 is a severe acute respiratory disease caused by the coronavirus SARS-CoV-2.Since the first cases of infection registered in Wuhan, China in late 2019, it spread widely all over the world becoming a global pandemic
Results order to verify if SARS-CoV-2 able to replicate in neuronal HCN-2 cells we
Our results showed that SARS-CoV-2 was able to replicate in HCN-2 cells as suggested by the increase in copy number of N1 and N2 genes

Summary

Introduction

COVID-19 is a severe acute respiratory disease caused by the coronavirus SARS-CoV-2. Since the first cases of infection registered in Wuhan, China in late 2019, it spread widely all over the world becoming a global pandemic. The clinical manifestations of COVID-19 can vary going from an asymptomatic infection to mild, moderate, and severe respiratory illness with multi-organ dysfunctions that may lead to the death of the patient [1]. In particular, the oral cavity and nostrils, represent the access route for SARS-CoV-2 and protective personal equipment can be used to stop virus spreading among high risk jobs [3]. An increasing number of studies reported abnormalities of the central nervous system (CNS) and the peripheral nervous systems (PNS) in adult patients with COVID-19 [4,5,6,7]

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