Effect of thymoquinone on mouse dendritic cells

Area of Science:

• Immunology
• Pharmacology

Background:

• Thymoquinone from Nigella sativa exhibits anti-tumor and anti-inflammatory properties.
• Dendritic cells (DCs) are crucial for immune responses, with maturation and cytokine release triggered by lipopolysaccharides (LPS).
• The impact of thymoquinone on dendritic cell function remains largely unexplored.

Purpose of the Study:

• To investigate the effects of thymoquinone on lipopolysaccharide (LPS)-induced dendritic cell (DC) maturation, survival, and cytokine release.

Main Methods:

• Mouse bone marrow-derived DCs were treated with LPS and varying concentrations of thymoquinone.
• Flow cytometry (FACS) was used to analyze surface markers (CD11c, CD86, MHCII, CD54, CD40), caspase activation, and cell membrane scrambling (annexin V binding).
• Enzyme-linked immunosorbent assay (ELISA) measured cytokine levels (IL-10, IL-12p70, TNF-alpha), and Western blotting assessed Akt and ERK1/2 phosphorylation.

Main Results:

• Thymoquinone significantly blunted LPS-induced increases in DC maturation markers (CD86, MHCII, CD40, CD54) and pro-inflammatory cytokine release (IL-10, IL-12p70, TNF-alpha) in a dose-dependent manner.
• Thymoquinone promoted DC apoptosis by increasing caspase 3 and caspase 8 activation and annexin V binding, while LPS decreased these markers.
• Thymoquinone abrogated LPS-induced phosphorylation of pro-survival kinases Akt and ERK1/2.

Conclusions:

• Thymoquinone compromises LPS-induced dendritic cell maturation and cytokine production.
• Thymoquinone promotes dendritic cell apoptosis, counteracting the survival effects of LPS.
• These findings highlight thymoquinone's immunomodulatory potential by inhibiting DC activation and survival.