The inner of the two Muc2 mucin-dependent mucus layers in colon is devoid of bacteria

Abstract

We have recently shown that the colon is protected by an inner mucus layer that efficiently separates the bacteria in the outer mucus from the epithelial cells. The inner mucus is impervious for bacteria and built by a network formed by the MUC2 mucin. Lack or defects in this inner mucus layer allow bacteria to reach the epithelia, something that triggers colon inflammation.

Figures

Figure 1

The MUC2 mucin forms a network in mucus. (A) The domain organization of the MUC2 mucin. (B) The formation of MUC2 mucin in the endoplasmic reticulum, in the Golgi apparatus, and as released from the goblet cells.

Figure 2

The mucus layers protect the colon epithelium. The inner firmly attached mucus layer is continuously renewed by the goblet cells and transformed from the inner firm mucus layer to the outer loose mucus layer as shown by the dotted arrow. The distances given are for mouse.