Abstract: Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis worldwide.
The tropism of HEV is not restricted to the liver, and the virus replicates in other organs. Not all
the extrahepatic targets for HEV are identified. Herein, we found that non-decidualized primary
human endometrial stromal cells (PHESCs), which are precursors for the decidua and placenta,
are susceptible to HEV infection. PHESCs, isolated from healthy non-pregnant women (n = 5),
were challenged with stool-derived HEV-1 and HEV-3. HEV RNA was measured by qPCR, and
HEV capsid protein was assessed by flow cytometry, immunofluorescence (IF), and ELISA. HEV
infection was successfully established in PHESCs. Intracellular and extracellular HEV RNA loads
were increased over time, indicating ecient replication in vitro. In addition, HEV capsid protein
was detected intracellularly in the HEV-infected PHESCs and accumulated extracellularly over time,
confirming the viral assembly and release from the infected cells. HEV-1 replicated more eciently in
PHESCs than HEV-3 and induced more inflammatory responses. Ribavirin (RBV) treatment abolished
the replication of HEV in PHESCs. In conclusion, PHESCs are permissive to HEV infection and
these cells could be an endogenous source of HEV infection during pregnancy and mediate HEV
vertical transmission.