Obesity and neuroinflammation : the impact of adipocyte-derived extracellular vesicles on microglial cell signalling

Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2022
Thesis identifier
  • T16293
Person Identifier (Local)
  • 202052046
Qualification Level
Qualification Name
Department, School or Faculty
  • Background: Obesity is becoming an increasingly prominent disease associated with many comorbidities. Although it is well established that obesity is a chronic inflammatory disorder, the mechanisms involved in this process are not fully known. The onset and development of obesity-induced neuroinflammation is poorly understood. Extracellular vesicles (EVs) are nanoparticles released from most cell types and aid in cell-cell communication. Adipocyte-derived extracellular vesicles (AT-EVs) are known to be involved in interorgan crosstalk during obesity and therefore may be a key component in obesity induced neuroinflammation. Aim and Hypothesis: To understand the effects of AT-EVs on microglial cells and if this may be a contributing factor in the link between obesity and neuroinflammation. We hypothesise that AT-EVs will enhance the expression of pro-inflammatory signalling (pNF-κB expression) within microglial cells. Methods: Using morphological and cell viability techniques, two microglial cell lines, HMC3 and BV2 cells were characterised under normal and inflammatory conditions (1μg/mL and 10μg/mL of LPS). AT-EVs were isolated and characterised using ultracentrifugation and light scattering techniques (dynamic light scattering and nanoparticle tracking analysis). Immunofluorescence measured vesicle uptake in microglial cells. Silver staining was done to detect total protein content within EV samples. Western blotting analysed pNF-κB expression in microglial cells after co-culturing with AT-EVs. Results: HMC3 and BV2 cells express a morphologically inflammatory phenotype when stimulated with LPS. Healthy AT-EVs are of certain size (~180nm) and concentration (~3x108particles/mL) and are found to contain protein. AT-EVs are successfully internalised by BV2 cells and healthy AT-EVs (5μg/mL) grown under normal conditions result in pNF-κB upregulation. Conditioned EVs express differences in vesicle concentration (hypoxic EVs have higher concentration [3.5 x 108 particles/mL] compared with healthy [2.5 x 108 particles/mL] and IR EVs [2.1 x 108 particles/mL]) as well as protein content. Conclusion: AT-EVs evoke pro-inflammatory signalling in BV2 cells. In depth characterisation of the pro-inflammatory phenotypes for both cell lines were incomplete and must be further addressed. Future work must explore the functional effects of conditioned AT-EVs on microglial cells to examine if these vesicles exacerbate the pro-inflammatory phenotype. Keywords: Adipocytes, Extracellular vesicles, Microglia, Neuroinflammation, Obesity
Advisor / supervisor
  • Rattray, Zahra
  • Gould, Gwyn W.
  • Cunningham, Margaret
Resource Type
Date Created
  • 2021
Embargo Note
  • This thesis is restricted to Strathclyde users only.