ABSTRACT
In the three years since the first outbreak of COVID-19 in 2019, the SARS-CoV-2 virus has continued to be prevalent in our community. It is believed that the virus will remain present, and be transmitted at a predictable rate, turning endemic. A major challenge that leads to this is the constant yet rapid mutation of the virus, which has rendered vaccination and current treatments less effective. In this study, the Lactobacillus sakei Probio65 extract (P65-CFS) was tested for its safety and efficacy in inhibiting SARS-CoV-2 replication. Viral load quantification by RT-PCR showed that the P65-CFS inhibited SARS-CoV-2 replication in human embryonic kidney (HEK) 293 cells in a dose-dependent manner, with 150 mg/mL being the most effective concentration (60.16% replication inhibition) (p < 0.05). No cytotoxicity was inflicted on the HEK 293 cells, human corneal epithelial (HCE) cells, or human cervical (HeLa) cells, as confirmed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The P65-CFS (150 mg/mL) also reduced 83.40% of reactive oxidizing species (ROS) and extracellular signal-regulated kinases (ERK) phosphorylation in virus-infected cells, both of which function as important biomarkers for the pathogenesis of SARS-CoV-2. Furthermore, inflammatory markers, including interferon-α (IFN-α), IFN-ß, and interleukin-6 (IL-6), were all downregulated by P65-CFS in virus-infected cells as compared to the untreated control (p < 0.05). It was conclusively found that L. sakei Probio65 showed notable therapeutic efficacy in vitro by controlling not only viral multiplication but also pathogenicity; this finding suggests its potential to prevent severe COVID-19 and shorten the duration of infectiousness, thus proving useful as an adjuvant along with the currently available treatments.
ABSTRACT
In response to the ongoing COVID-19 pandemic, the global effort to develop high efficacy countermeasures to control the infection are being conducted at full swing. While the efficacy of vaccines and coronavirus drugs are being tested, the microbiome approach represents an alternative pathophysiology-based approach to prevent the severity of the infection. In the current study, we evaluated the action of a novel probiotic Lactobacillus plantarum Probio-88 against SARS-COV-2 replication and immune regulation using an in vitro and in silico study. The results showed that extract from this strain (P88-CFS) significantly inhibited the replication of SARS-COV-2 and the production of reactive oxygen species (ROS) levels. Furthermore, compared with infected cells, P88-CFS treated cells showed a significant reduction in inflammatory markers such as IFN-α, IFN-ß, and IL-6. Using an in silico molecular docking approach, it was postulated that the antiviral activity of L. plantarum Probio-88 was derived from plantaricin E (PlnE) and F (PlnF). The high binding affinity and formation of hydrogen bonding indicated that the association of PlnE and PlnF on SARS-COV-2 helicase might serve as a blocker by preventing the binding of ss-RNA during the replication of the virus. In conclusion, our study substantiated that P88-CFS could be used as an integrative therapeutic approach along with vaccine to contain the spread of the highly infectious pathogen and possibly its variants.