Coronaviruses are a group of viruses that cause severe respiratory symptoms. Lipid membranes envelop the viral RNA. Viruses enter the cell through the endocytic pathway. Controlling this pathway has potential for developing treatments against coronaviruses.
The author writes to compare data that looks into the effectiveness of controlling the endocytic pathway as a treatment for coronaviruses. The author also presents possible treatments.
Autophagy and the Endocytic Pathway
A diverse range of organisms take part in autophagy. Autophagy is the process where a cell envelopes and breaks down material in a vesicle. An autophagosome refers to the vesicle and what is inside. The autophagosome binds with a lysosome that breaks down what is inside. The acidic material then breaks down what is inside the autophagosome.
A similar process called the endocytic pathway takes in material outside the cell. The material taken in as well as the membrane surrounding it is called an endosome. This material is either broken down by a lysosome or sent elsewhere for recyclying. Figure 1 draws out both of these processes.
Implication of Autophagy in Coronaviruses' Infection
Data collected by researchers on Mouse Hepatitis Virus (MHV) implies the involvement of autophagy in copying the virus's DNA. This copying of the DNA is how a virus reproduces and spreads to other cells in the body. The structure that envelopes the DNA looks like an autophagosome. This then attracts proteins that will copy the viral genome. Data shows that coronaviruses are involved in this process.
Despite the evidence collected in the findings above, other researchers have found evidence to go against these conclusions. Snijder et al failed to show that the proteins related to autophagosomes present near the viral genome in the cell. This would mean that there may be other processes that control the copying of viral DNA. Table 1 illustrates this. It shows the data from several viruses and what the findings were.
Involvement of the Endocytic Pathway in CoVs Infection
The endocytic pathway is one of the main ways a coronavirus enters a cell. Data in Table 2 supports this claim. This table organizes each row by the virus tested and pairs it with the endocytic process studied. The inhibitors refer to what stopped the endocytic pathway from happening. Then "Main Findings" summarizes the results of inhibiting the "machinery" in that row.
While autophagy's importance to the virus's infection is debatable, there is a large amount of support and evidence to suggest the endocytic pathway has great potential for finding treatments to coronaviruses.