Anti-inflammatory effects of S-1-propenyl-L-cysteine, a major constituent of Aged Garlic Extract: inhibition of proinflammatory mRNA expression in BNT162b2-stimulated human bronchial epithelial IB3-1 cells.

Aged Garlic Extract (AGE) and its bioactive constituents are known for their ability to counteract hyperinflammatory responses triggered by proinflammatory stimuli, such as the cytokine storm involved in Acute Respiratory Distress Syndrome (ARDS) associated with severe COVID-19. This study aimed to investigate the effects of S-1-propenyl-L-cysteine (S1PC), a key component of AGE, on the human bronchial epithelial cell line IB3-1 following exposure to the mRNA vaccine BNT162b2, used as an in vitro model for inflammatory response. The mRNA vaccine BNT162b2 encodes for the SARS-CoV-2 Spike protein. BNT162b2 stimulated cells IB3-1 were treated with S1PC at concentrations of 1, 5, 10, 25, 50, and 100 μM for 48 hours. Following treatment, reverse transcription quantitative PCR (RT-qPCR) and western blot analyses were conducted. The results revealed that the accumulation of Spike mRNA and protein in IB3-1 cells exposed to BNT162b2 vaccine stimulation was associated with a pronounced upregulation of the transcription factor NF-κB and its downstream target genes, including IL-6, IL-8, and granulocyte colony-stimulating factor (G-CSF), all involved in the COVID-19 cytokine storm. Notably, S1PC treatment reversed this upregulation without affecting cell viability, apoptosis, cell cycle and proliferation efficiency. These findings suggest that S1PC may serve as a potential inhibitor of vaccine-induced inflammatory responses. Further studies are needed to identify additional agents that could act synergistically with S1PC to enhance its anti-inflammatory effects and elucidate the underlying molecular mechanisms.