- Title
- The action of sutherlandia frutescens on macrophage differentiation & function
- Creator
- Camille, Ned
- Subject
- Medicinal plants Macrophages
- Date Issued
- 2017
- Date
- 2017
- Type
- Thesis
- Type
- Masters
- Type
- MSc
- Identifier
- http://hdl.handle.net/10948/22112
- Identifier
- vital:29841
- Description
- Sutherlandia frutescens (S. frutescens) is a medicinal plant, indigenous to South Africa used to treat various conditions, including Type II Diabetes (T2D) and immune disorders. Many of these conditions involve the macrophage lineage in low grade chronic inflammation, characterized by elevated pro-inflammatory cytokines. The macrophage population can be divided into pro-inflammatory (M1) and anti-inflammatory (M2) sub-populations. S. frutescens is believed to possess the potential to regulate macrophage differentiation and metabolic immune diseases. This makes it important to investigate its molecular action to determine its potential ethnopharmacological use. The aims of this study were to explore the role of S. frutescens on M1/M2 macrophage function, using extracts prepared from a single plant source previously shown to target T2D, and to determine its potential mechanistic pathways using the murine macrophage-like RAW 264.7 cell line. The action of a hot aqueous and a 100% ethanolic extract of S. frutescens were tested in the RAW 264.7 cell line following Lipopolysaccharide (LPS) induction. The effect of these extracts on activation of a pro-inflammatory M1 phenotype and an anti-inflammatory M2 phenotype was investigated by flow cytometry using the CD markers CD86 (M1) and CD206 (M2). M1 macrophage pro-inflammatory responses were measured by production of nitric oxide (NO) using the Griess reagent and reactive oxygen species (ROS) production and cyclooxygenase 2 (COX-2) expression by flow cytometry. Cytokine production was quantified by ELISA assays. Toll-like receptor-4 (TLR4), inducible nitric oxide synthase (iNOS) (M1) and Heme-oxygenase 1 (HMOX-1) (M2) mRNA expression were quantified by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Arginase-1 activity (M2) was measured by the urea assay. The effect of S. frutescens extracts on nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-κB) and mitogen activated protein kinases (MAPK) signaling pathway were determined with flow cytometry and Image Express XLS microscopy. After 24 hour treatment, both the hot aqueous and ethanolic extracts of S. frutescens significantly inhibited all M1 functions, and altered the pattern of CD expression from M1 (CD86+) to M2 (CD206+) in RAW 264.7 cells following activation by LPS, with the ethanolic extract having the greatest activity. M1-type cytokines were downregulated, while the M2 cytokine profile remained unchanged. S. frutescens was shown to mediate its action through suppression of both NF-κB and MAPK pathways and not through HMOX-1, exerting most activity through decreased p38 MAPK phosphorylation. We show that S. frutescens aids in the potential reversal of imbalances in the macrophage M1 and M2 sub-populations, leading to amelioration of disease. We hypothesize that regulation occurs during the differentiation and activation processes, with reduction in inflammation and direction towards M2 anti-inflammatory activity. This could promote tissue remodeling and immune regulation and has potential to alleviate the pathogenesis of both T2D and immune diseases.
- Format
- xxi, 183 leaves
- Format
- Publisher
- Nelson Mandela Metropolitan University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela Metropolitan University
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NMU School of BioMolecular and Chemical Sciences
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