Investigating the effect of plant-derived extracellular vesicles on human placental function

  • Katherine Timms

Student thesis: Phd


A maternal diet high in fruits and vegetables is associated with increased placental size and birthweight and decreased incidence of preeclampsia. This relationship is not explained by maternal socioeconomic status or levels of micro- and macronutrients in the diet, suggesting that an, as yet, unaccounted for nutrient could be contributing to fetal growth. Extracellular vesicles (EVs) are a recently identified component of fruits and vegetables. EVs are nanosized lipid-encased parcels of protein, RNA and other molecules that can alter the function of recipient cells. Fruit and vegetable EVs are internalised into mouse intestinal cells. It was, therefore, hypothesised that EVs from plants consumed as part of the diet would be internalised into human intestinal cells, resulting in the transmission of plant and/or intestinal-derived signals to the placenta, altering placental growth, development or function and thereby linking maternal fruit and vegetable intake to fetal growth. EVs derived from watermelon (WMEVs) were isolated using ultracentrifugation and found to be of a size and morphology consistent with the EV subtype known as exosomes. Mass spectrometry and qPCR arrays were used to identify that WMEVs exhibit protein, lipid and miRNA profiles that differ from watermelon cells, suggesting that their contents are likely actively loaded. Further analysis of the WMEV proteome predicted a possible dual origin from the endosome and plastid for these WMEVs and suggested they may have a role in watermelon fruit ripening. WMEVs were labelled with a lipid (PKH26) or RNA (SYTO RNAselect) dye and incubated apically with Caco-2 cells differentiated on transwell membranes into small intestine-like epithelial cells. Flow cytometry determined that PKH26-labelled WMEVs were internalised into Caco-2 cells in a time (49.45% of cells at 180 minutes; p1.5-fold upregulated; 13 proteins >1.5-fold downregulated) in response to WMEVs. Caco-2 secretion of fetuin-A, an inhibitor of extravillous trophoblast (EVT) migration and trophoblast viability, was decreased (4.3-fold lower; p
Date of Award31 Dec 2018
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorAnil Day (Supervisor), John Mclaughlin (Supervisor), Melissa Westwood (Supervisor) & Karen Forbes (Supervisor)


  • nutrition
  • diet
  • extracellular vesicle
  • trophoblast
  • pregnancy
  • placenta
  • watermelon

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