HCFC1R1 Plays An Essential Role In Herpes Simplex Virus-1 Infection

Herpes simple virus type 1?HSV-1?,a common pathogen that is harmful to human health,can infect host cells through damaged skin or mucosa and cause a variety of herpes-like diseases.In addition,HSV-1 can infect host neurons through epithelial nerve endings,ultimately establishing a latent infection mechanism in the host trigeminal ganglion.Humans are the only natural host of HSV-1 infection,and nearly 90%of the world's population is infected with HSV-1.Once infected,HSV-1 is often accompanied by the host permanently,and re-emerges through latent infection,resulting in a series of human diseases such as human mouthwash,herpetic keratitis,and herpetic encephalitis.Recent studies have shown that the proportion of HSV-1 in genital herpes is also increasing,and has a certain relationship with the occurrence of Alzheimer's disease.Currently,the most effective treatment for HSV-1 infection is acyclovir?ACV?and a series of its derivatives.HSV-1 thymidine kinase TK phosphorylates ACV and its derivatives,and the incorporation of phosphorylated products into newly synthesized viral DNA strands blocks the continued synthesis of DNA.However,in the process of HSV-1 evolution,the viral TK gene may undergo gene mutation,resulting in a mutant strain capable of resisting ACV.Due to the strong mutation of HSV-1 virus,it is easy to lead to the emergence of viral resistance,and there is currently no effective drug that can completely cure HSV-1 and a vaccine against HSV-1.Therefore,finding new vaccines or drugs is imperative for the treatment of diseases caused by HSV-1!Previously,our laboratory screened a number of candidate genes that are resistant to HSV-1 infection in human gastric cancer cell line BGC823 by screening the human CRISPR whole genome knockout library,one such candidate is HCFC1R1.The known host cell factor 1?HCFC1?is involved in the regulation of immediate early gene expression of the virus,and HCFC1R1 is a regulator of HCFC1.The detailed mechanism involved in HSV-1 infection remains unclear.BGC823 cells are resistant to HSV-1infection after knockout of HCFC1R1,and the cell antiviral capacity is diminished when the expression of HCFC1R1 protein is restored in knockout cells.The forward and reverse experiments confirmed that the cells were resistant to HSV-1 virus infection after deletion of HCFC1R1,indicating that HCFC1R1 is indeed involved in the HSV-1infection process.We then detected the expression levels of virus-associated proteins?ICP0,ICP4,TK,gD,VP16?by Western blot and found that the expression levels of these viral proteins were decreased in BGC823^hcfc1r1-/-cells,demonstrating that these were inhibited in BGC823^hcfc1r1-/-cells.The nuclear transport of the virus hinders the proliferation and replication process of the virus and avoids the lytic death of the virus by the host cell.We also found that HCFC1R1 does not carry the virus into the host cell as a viral membrane receptor,nor does it activate the host cell interferon pathway to resist viral infection.In the case of viral infection,the HSV-1 VP16 protein interacts with the host factor 1HCFC1,and the VP16 protein is carried into the nucleus to activate immediate early gene expression.HCFC1 plays an important role in viral gene expression as a viral host interaction factor.The experiment demonstrated that the host cytokine regulatory factor HCFC1R1 is also involved.HSV-1 VP16 protein was detected in BGC823^hcfc1r1-/-cytoplasm after viral infection,but VP16 protein was not detected in the nucleus.When the virus infects BGC823 WT cells,VP16 protein can be detected in both nucleus and cytoplasm.These results indicate that the nuclear import process of VP16 protein in BGC823^hcfc1r1-/-cells is affected,suggesting that HCFC1R1 is involved in the entry of viral VP16 protein.In summary,we demonstrate the importance of HCFC1R1 for the proliferation and replication of viruses in host cells from the perspective of the interaction between viruses and host-dependent factors.These studies provide a theoretical support for the pharmaceutical development by targeting HCFC1R1 or its related pathway.