ABSTRACT
Objective: This study aims to evaluate the effect of Clostridium perfringens sialidase treatment on monolayer cell behavior using computational screening and an in vitro approach to demonstrate interaction between enzyme-based drugs and ligands in host cells. Materials and Methods: The in silico study was carried out by molecular docking analysis used to predict the interactions between atoms that occur, followed by genetic characterization of sialidase from a wild isolate. Sialidase, which has undergone further production and purification processes exposed to chicken embryonic fibroblast cell culture, and observations-based structural morphology of cells compared between treated cells and normal cells without treatment. Results: Based on an in silico study, C. perfringens sialidase has an excellent binding affinity with Neu5Acα (2.3) Gal ligand receptor with Gibbs energy value (∆G)-7.35 kcal/mol and Ki value of 4.11 µM. Wild C. perfringens isolates in this study have 99.1%-100% similarity to the plc gene, NanH, and NanI genes, while NanJ shows 93.18% similarity compared to the reference isolate from GenBank. Sialidase at 750 and 150 mU may impact the viability, cell count, and cell behavior structure of fibroblast cells by significantly increasing the empty area and perimeter of chicken embryo fibroblast (CEF) cells, while at 30 mU sialidase shows no significant difference compared with mock control. Conclusion: Sialidase-derived C. perfringens has the capacity to compete with viral molecules for attachment to host sialic acid based on in silico analysis. However, sialidase treatment has an impact on monolayer cell fibroblasts given exposure to high doses.
ABSTRACT
Objective: The Newcastle disease virus (NDV) is an infectious disease that causes very high economic losses due to decreased livestock production and poultry deaths. The vaccine's ineffectiveness due to mutation of the genetic structure of the virus impacts obstacles in controlling the disease, especially in some endemic areas. This study aimed to provide an alternative treatment for NDV infection by observing the viral replication inhibitor activity of Clostridium perfringens sialidase in primary chicken embryo fibroblast (CEF) cells. Materials and Methods: The virus was adapted in CEF monolayer cells, then collected thrice using the freeze-thaw method and stored at -20°C for the next step in the challenge procedure. C. perfringens crude sialidase was obtained, but it was further purified via stepwise elution in ion exchange using Q Sepharose® Fast Flow and affinity chromatography with oxamic acid agarose. The purified sialidase was tested for its toxicity, ability to breakdown sialic acid, stopping viral replication, and how treated cells expressed their genes. Results: According to this study, purified C. perfringens sialidase at dosages of 187.5, 93.75, and 46.87 mU effectively hydrolyzes CEF cells' sialic acid and significantly inhibits viral replication on the treated cells. However, sialidase dosages of 375 and 750 mU affected the viability of monolayer CEF cells. Interestingly, downregulation of toll-like receptor (TLR)3 and TLR7 (p < 0.05) in the sialidase-treated group indicates viral endocytosis failure. Conclusions: By stopping endocytosis and viral replication in host cells, sialidase from C. perfringens can be used as an alternative preventive treatment for NDV infection.
