In addition to the respiratory tract, the new coronavirus can indeed infect intestinal cells!

new coronary pneumonia caused by the new coronavirus (SARS-CoV-2) infection continues to explode worldwide, with more than 3.5 million confirmed cases and more than 245,000 deaths as of May 4. Previous studies have shown that prickly proteins on the surface of the new coronavirus can bind to angiotensin-converting enzyme 2 (ACE2) of infected cells to invade the human body, while soluble ACE2 inhibits SARS-CoV-2 infection.The virus can be detected in human upper respiratory tract samples, the nasopharyngeal as a replication point, mainly transmitted by respiratory droplets, and ACE2 is mainly expressed in the human lung type II vesicle endothos cells and fibre cells, which is consistent with the respiratory symptoms caused by the virus and severe lung injury symptoms.However, the researchers found that the highest expression of ACE2 in the human body is in the small intestine cortical cells brush edge, COVID-19 clinical manifestations, in addition to the main respiratory symptoms, some patients have obvious gastrointestinal symptoms, in addition, even in the nasopharyngeal test virus nucleic acid, rectal swabs can detect viral RNA, which seems to suggest that SARS-CoV-2 can also infect intestinal cells, through fecal-oral transmission.Recently, researchers from the Netherlands confirmed this hysteresic finding that SARS-CoV-2, in addition to respiratory cells, can also infect and replicate human small intestine organs (hSIOs), which can be used as a new experimental model for the study of coronavirus infections. The findings were published May 1, 2020 in science, a leading academic journal.Using adult stem cells (ASCs), the researchers developed organs of the human respiratory tract and small intestine, which typically have all the types of proliferating and differentiated cells that are organ-specific and reproduce the function of the organs they represent. By adding the virus to respiratory organs, SARS-CoV-2 can be observed to infect cerum cells in the organs without targeting cup cells. HSIO, a small intestine organ grown under four different culture conditions, was exposed to SARS-CoV-2 and samples from multiple points in time after infection were collected. By qRT-PCR and live virus titration observation, the titration of infectious virus particles detecting SARS-CoV-2 was significantly increased. This suggests that the new coronavirus can infect respiratory and intestinal organs.To further determine the type of intestinal target cells infected, the researchers performed a cofocus analysis of hSIO cultured with three conditions to visualize the rate of viral infection in growing organs. The results showed that the number of infected cells in the grown organs in the three cases gradually increased within 60 hours, while the infected cells always showed up as progenitotyte esocytestypes of progenitokines of progenitokines of the progenitokin of the progenixual intestinal cortical cells or ApoA1 plus intestinal endocyte esopaedic esoporasia, indicating that SARS-CoV-2 is susceptible to infection of intestinal cortical cell genealogy cells.The researchers also performed electron microscopy (TEM) tests on highly infected cells to observe 42 hSIO imagings within 60 hours of SARS-CoV-2 infection, the life cycle of the virus in the intestinal cortical cells. It was found that 80-120 nm of viral particles appeared in the inner cavity of the organ, on the outside and top sides of the substrate of the substrate cells, and the replication of the virus in the bi-membrane vesicles was also observed.Subsequently, the researchers used transcriptional group sequencing to detect changes in gene expression induced by SARS-CoV-2 infection hSIO, and genetic annotations showed that the infection caused by type I and type III interferon responses to a wide range of expressions of cytokine and interferon stimulation genes (ISGs), including ACE2 expression, which was further validated by ELISA and q-PCRTR. In addition, the researchers observed that SARS-CoV-2 had a similar rate of infection in the pregeneral and endothor cells of the intestinal cortectal cells, but that the expression of ACE2 in the intestinal cortectal cells increased by about 1,000 times compared to the pregeneral cells, suggesting that low levels of ACE2 may be sufficient to enter the virus.All in all, the researchers determined that the new coronavirus can infect intestinal cortical cells, and demonstrated that hSIOs could be used as a new experimental model for coronavirus infection research.SARS-CoV-2 is the third highly pathogenic coronavirus after SARS-CoV and MERS-CoV, which has been transmitted to humans as a coronavirus in less than 20 years, and a new type of zoonotic coronavirus may occur in the future. Therefore, the study of the pathogenesis and transmission of coronavirus, as well as the development of in-body cell models that can accurately simulate host tissue, play an important role in the future to overcome coronavirus.
(Sina Pharmaceutical News)