In Vitro Studies on the Immunomodulatory Effects of Pulicaria crispa Extract on Human THP-1 Monocytes

Abstract EN

Background.

Pulicaria crispa (P.

crispa) is a plant from the Compositae family that exhibits antioxidant, anti-inflammatory, antibacterial, and cytotoxic activities.

Objective.

The current study aimed at investigating the immunomodulatory effects of P.

crispa extract in lipopolysaccharide- (LPS-) stimulated human monocytic THP-1 cells.

Methods.

To induce macrophage differentiation, THP-1 cell lines were treated with phorbol-12-myristate 13-acetate, followed by exposure to LPS with or without 50 or 100 μg/ml of P.

crispa extract.

The following tests were employed to test the immunomodulatory effects of the extract: MTT assay, ELISA, Western blotting analysis, cell migration and phagocytosis assays, and Annexin V staining method.

Results.

Exposure to 100 μg/ml P.

crispa extract significantly reduced THP-1 cell proliferation, migration, and phagocytosis (in LPS-stimulated cells, but not in unstimulated cells).

Moreover, the extract alone significantly reduced the rate of THP-1 cell apoptosis, while it increased the rate of late apoptosis.

Molecular investigations showed that treatment with P.

crispa extract significantly upregulated the expression of ERK1, p-MAPK, P-P38, and Bcl2, while it significantly reduced the expression of ERK5, Bax, NF-κB, P-NF-κB, CCL1, CCL2, CCL5, CCL22, CXCL1, and CXCL10.

Conclusion.

Pulicaria crispa extract exhibited anti-inflammatory, antiproliferative, antimigratory, and antiphagocytic effects in LPS-stimulated THP-1 cells.

Future studies should investigate these mechanisms in animal models with chronic inflammatory diseases.