Profiling epithelial viral receptor expression in amniotic membrane and nasal epithelial cells at birth.

Introduction: Children with wheeze and asthma present with airway epithelial vulnerabilities, such as impaired responses to viral infection. It is postulated that the in utero environment may contribute to the development of airway epithelial vulnerabilities. The aims of the study were to establish whether the receptors for rhinovirus (RV), respiratory syncytial virus (RSV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are expressed in the amniotic membrane and whether the pattern of expression is similar to newborn nasal epithelium.

Methods: Placenta were collected (n = 33) from newborns in AERIAL, a sub-study nested under the ORIGINS birth cohort. Using purified RNA from amniotic samples (n = 33), along with previously extracted RNA from nasal epithelial cells from newborns (n = 20), real-time quantitative polymerase chain reaction (qPCR) was performed to determine gene expression of viral receptors for RV, RSV and SARS-CoV-2 in both amniotic and newborn nasal epithelial samples. In addition, receptor protein expression was quantified through Western blot and localised using immunohistochemical staining in amniotic samples.

Results: Amniotic and newborn nasal samples expressed various receptors for RV (ICAM-1, LDLR, CDHR3), RSV (NCL, CX3CR1) and SARS-CoV-2 (ACE2, TMPRSS2) at the gene level, although the magnitude of expression varied. In addition, protein expression of these receptors was confirmed in the amniotic samples. These proteins were localised to the epithelial layer of the amniotic membrane.

Conclusion: This proof-of-concept study indicates the potential of amniotic samples to facilitate investigation into the interactions between the in utero environment and prenatal programming of epithelial innate immune responses to viruses.