Gut epithelial cells

There are trillions of bacteria in the normal human gut - there are far fewer in the preterm infant gut, but still the gut remains a source of potential pathogens, as well as potentially 'healthy' bacteria. One of our earlier studies showed that the bacteria responsible for sepsis (blood poisoning) were always detectable in the infant gut prior to development of sepsis. We also know that NEC does not develop prior to birth (even if the fetus is hypoxic) suggesting that you need bacteria for NEC to occur.


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Figure 1. Co-culture of epithelial cells with E coli
What is amazing is that the simple lining of the gut (epithelium) must somehow keep harmful bacteria at bay, whilst still allowing the absorption of important nutrients.Our group is exploring how the gut epithelium responds to the types of stresses and exposures likely to be faced by preterm infants. Of course, this cannot be done in preterm infants themselves, so we are developing cell models in the lab. We can then explore how these gut cells respond to bacteria by measuring the production of pro-inflammatory cytokines.
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Figure 2. Established monolayer with undulating primitive villous structure
We are exploring the relationship between the innate immune response and its modulation by clinical interventions carried out on the neonatal unit. We assay the cytokine response of epithelial monolayers, performed using 3 fold analysis;

  1. direct ELISA cytokine assay(il-8, il-6, TNF alpha) of the supernatant surrounding the cells,
  2. MicroRNA analysis of the cellular tissue and
  3. direct PCR for gene expression focussing on the NF kappa B and the SMAD pathways.
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Figure 3. Immunoflouresence of monolayer for bacterial invasion assay
The relationship between dysbiosis and the developing immune system, supports the need to explore in vitro interactions between gut pathogens and gut epithelium. We are assessing the virulence of bacteria to the monolayer and how these interactions are modulated.  For this we using varying imagining modalities include confocal imaging and immunofluorescence.