Microbiota

Microbiota

Community of microorganisms that colonize a specific environment

Functions of bacteria

1. Digestion of complex glycans

2. Synthesis of vitamins and metabolites

3. Maturation of the immune system

How are the functions possible?

Diversity of genes in the bacteria, not found in the human genome = expands our metabolic capacities

Imbalance

Causes diseases (C. difficile) because many functions are accomplished by the microbiota

Anti PD-L1/CTLA-4 therapy

Prevents the binding of the inhibitory ligand of the PD-1 receptor = T-cell activation restored and anti-tumor activity

FMT conclusion

Specific gut microbes enhance the immune system’s response to cancer immunotherapy

How can NR microbiota be altered to ressemble R microbiota? (3)

1. FMT

2. Probiotics

3. Prebiotics

Probiotics

Live bacteria that are cultured and administered to a host

Main disadvantage of probiotic consumption

Requires knowledge of specific bacteria strais that affect certain diseases (+consortium)

Prebiotics

Molecules that promote the growth of beneficial gut bacteria

Main problem with prebiotic consumption

Who eats what?

Prebiotics that have been proven to support the beneficial gut bacteria

- Inulin and levan (dietary fiber)

- Castalagin (polyphenol)

What do dietary fibers break into?

Into complex glycans (legumes, grains)

Importance of dietary fibers

Gut bacteria expresses thousands of enzymes that breaks them down compared to a few in the human genome

Levan and tumor size

Little to no improvement

Inulin and tumor size

Significantly smaller = enhances immunotherapy

Castalagin and cancer

Significantly smaller = improves the response to immunotherapy

FACS

Fluorescence-actived cell sorting

How does FACS work?

Uses fluorescent markers and flow cytometry to analyze and physically separate cells based on specific characteristic

Step 1

Fluorescently label dietary fiber and feed it to bacteria

Step 2

Bacteria that consumed the fiber become fluorescent

Step 3

Bacteria is vaporized into droplets

Step 4

Electric current zaps fluorescent droplets and give them a charge

Step 5

Sort bacteria according based on charge