Lypd8 promotes the segregation of flagellated microbiota and colonicepithelia■ Invasion of intestinal bacterium induces intestinal inflammation. Mechanisms to inhibit theinvasion have remained unclear.
■ Takeda’s group revealed that the protein, Lypd 8, expressed in epithelial cells on the intestinal
gland, regulates intestinal bacterial invasion of the colonic mucosa.
■ These findings could shed light into the development of novel therapies for ulcerative colitis, forwhich there is no definitive treatment at the moment.

Summary Figure

Ly6/PLAUR domain containing 8 (Lypd8), which is a highly glycosylated GPI-anchored protein, ishighly and selectively expressed in epithelial cells on the uppermost layer of the intestinal gland andshed into the intestinal lumen. Lypd8 inhibits intestinal bacterial invasion of the colonic mucosa bybinding to the intestinal bacteria, and thereby regulates the intestinal inflammation.

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Figure 1. Lypd8 expression in the mouse colon.
Immunostaining with anti-Lypd8 antibody(Lypd8), FISH using bacteria-specific probe(bacteria), and DAPI (colon) of Carnoy’s
fixed colon sections. It was found that Lypd8
is highly expressed at the uppermost layer ofthe intestinal gland and shed into theintestinal lumen.

Figure 2. Decrease of Lypd8 expression in the human colon of ulcerative colitis
patients.
Immunostaining (upper panel) with
anti-Lypd8 antibody (Lypd8) and DAPI(colon) and hematoxylin-eosin staining(lower panel) of human colon sections
from the normal mucosa of a coloncancer patient and the inflammatory
mucosa of two ulcerative colitis (UC)patients. It was found that Lypd8
expression is severely decreased in theinflamed mucosa of UC patients.

2Figure 3. Many intestinal bacteria penetrate into the inner mucus layer in Lypd8deficient mice.
Immunostaining with anti-Muc2
antibody (mucus), FISH using
bacteria-specific probe (bacteria)
and DAPI (colon) of Carnoy’s
fixed colon sections. It wasobserved that many intestinalbacteria penetrate into the innermucus layer in Lypd8-deficient
mice, but not in wild-type mice.

Figure 4. The numbers of flagellated bacteria such as Proteus, Escherichia andHelicobacter are tremendously increased in Lypd8-/- colonic tissues.
Quantitative PCR of bacterial DNA in colon
tissues using bacterial genus–specific primers
was performed. Data show each bacterial DNA
amount compared to WT mice group. The
numbersofProteus,

Escherichia

andHelicobacter, all of which are flagellated bacteria,
were increased in colonic tissues of Lypd8deficient mice, compared to those of wild-type mice.

Figure 5. Lypd8-deficient mice are highly susceptible to dextran sulfate sodium(DSS)-induced colitis.
Survival rate after 2% DSS administration of wild
type and Lypd8-deficient mice is shown. The
mortality of Lypd8-deficient mice was much higher
than that of wild-type mice. Lypd8 deficient mice
were highly susceptible to DSS-induced colitis.

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Figure 6. Lypd8 binds to flagella of P. mirabilis.
Scanning

electronmicroscopic

imagesofP.

mirabilis labeled for immunogold detection of thebound Lypd8 are shown. White arrows indicate goldparticles.

Figure 7. Lypd8 suppresses the motility of P. mirabilis.
Representative photos of P.mirabilis motility
in semisolid agar with (right) or without (left)
Lypd8 protein at 4 h after incubation areshown. It was found that motility of P.
mirabilis was inhibited in semisolid agar
containing Lypd8 protein.

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