Hyperforin is a modulator of inducible nitric oxide synthase and phagocytosis in microglia and macrophages

Kraus, Birgit and Wolff, Horst and Elstner, Erich F. and Heilmann, Joerg (2010) Hyperforin is a modulator of inducible nitric oxide synthase and phagocytosis in microglia and macrophages. NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY, 381 (6). pp. 541-553. ISSN 0028-1298,

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Abstract

Upon activation, microglia, the immunocompetent cells in the brain, get highly phagocytic and release pro-inflammatory mediators like nitric oxide (NO). Excessive NO production is pivotal in neurodegenerative disorders, and there is evidence that abnormalities in NO production and inflammatory responses may at least support a range of neuropsychiatric disorders, including depression. Although extracts of St. John's wort (Hypericum perforatum L.) have been used for centuries in traditional medicine, notably for the treatment of depression, there is still considerable lack in scientific knowledge about the impact on microglia. We used N11 and BV2 mouse microglia, as well as RAW 264.7 macrophages to investigate the effects of St. John's wort extract and constituents thereof on NO production Moreover, flow cytometry and fluorescence microscopy were employed to analyze the influence on phagocytosis, transcription factor activation states, and cell motility. We found that extracts of St. John's wort efficiently suppress lipopolysaccharide-induced NO release and identified hyperforin as the responsible compound, being effective at concentrations between 0.25 and 0.75 A mu M. The reduced NO production was mediated by diminished inducible nitric oxide synthase expression on the mRNA and protein level. In addition, at similar concentrations, hyperforin reduced zymosan phygocytosis to 20-40% and putatively acted by downregulating the CD206 macrophage mannose receptor and modulation of cell motility. We found that the observed effects correlate with a suppression of the activated state of Nf-kappaB and phospho-CREB, while c-JUN, STAT1, and HIF-1alpha activity and cyclooxygenase-2 expression remained unaffected by hyperforin. These results reveal that hyperforin influences pro-inflammatory and immunological responses of microglia that are involved in the progression of neuropathologic disorders.

Item Type: Article
Uncontrolled Keywords: ST-JOHNS-WORT; REGULATING SIGNAL TRANSDUCER; STIMULATED BV2 MICROGLIA; HYPERICUM-PERFORATUM L.; FORCED SWIMMING TEST; MANNOSE RECEPTOR; ANTIDEPRESSANT ACTIVITY; GENE-EXPRESSION; CELL-LINES; ACTIVATION; Hyperforin; Microglia; Hypericum perforatum; Inducible nitric oxide synthase; Phagocytosis; Motility; pCREB
Subjects: 600 Technology > 615 Pharmacy
Divisions: Chemistry and Pharmacy > Institute of Pharmacy > Pharmaceutical Biology (Prof. Heilmann)
Depositing User: Dr. Gernot Deinzer
Date Deposited: 29 Jul 2020 09:41
Last Modified: 29 Jul 2020 09:41
URI: https://pred.uni-regensburg.de/id/eprint/24655

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