OC 35.5 - Small intestinal villus vascularization is driven via an epithelial-to-endothelial PAR1 signaling axis

Monday, June 24, 2024

10:30 – 10:45 ICT

Room: 110 A-C

Presenting Author(s)

MM

Maximilian Mimmler, MSc

PhD student
Center for Thrombosis and Haemostasis, Universitätsmedizin Mainz
Mainz, Rheinland-Pfalz, Germany

Co-Author(s)

GP

Giulia Pontarollo

Postdoc
Center for Thrombosis and Haemostasis, Universitätsmedizin Mainz
Mainz, Rheinland-Pfalz, Germany
AM

Amrit Mann

PostDoc
Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz, Johannes Gutenberg University Mainz, Germany
Mainz, Rheinland-Pfalz, Germany
Klytaimnistra Kiouptsi, PhD

Postdoc
Center for Thrombosis and Hemostasis, University Medical Center, Johannes Gutenberg University Mainz
Mainz, Rheinland-Pfalz, Germany
FM

Frano Malinarich

Postdoc
Center for Thrombosis and Haemostasis, Universitätsmedizin Mainz
Mainz, Rheinland-Pfalz, Germany
NV

Nathalie Vergnolle

Team Leader
INSTITUT DE RECHERCHE EN SANTÉ DIGESTIVE, UNIVERSITÉ TOULOUSE PAUL SABATIER
Toulouse, Midi-Pyrenees, France
JM

Jean-Paul Motta

Postdoc
INSTITUT DE RECHERCHE EN SANTÉ DIGESTIVE, UNIVERSITÉ TOULOUSE PAUL SABATIER
Toulouse, Midi-Pyrenees, France
CR

Christoph Reinhardt

Group leader
Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz, Johannes Gutenberg University Mainz, Germany
Mainz, Rheinland-Pfalz, Germany

Background: Thrombin (F2) expression was recently reported in intestinal epithelial cells (IEC) impacting on microbial spatial organization and intestinal injuries. The thrombin receptor protease-activated receptor-1 (PAR1/F2r) is also expressed on IECs and in the context of inflammatory bowel disease, its activation is linked to disorders in gut mucosal healing. The gut microbiota can influence intestinal villus vascularization, required for nutrient harvest, in a tissue factor/PAR1-dependent fashion.

Aims: We aim to unravel the epithelial-endothelial-crosstalk between epithelial thrombin/PAR1 and small intestinal villus vascularization.

Methods: Mice deficient for intestinal epithelial F2 (F2ΔIEC) or F2r (F2rΔIEC) and endothelial F2r (F2rΔEC) were generated based on the Cre recombinase technology and used in age- and sex-matched groups.
Paraffin sections of the mid small intestine were stained by immunofluorescence to quantify the vascularized area in the small intestinal villus structures.
Gene expression was analyzed by qPCR with cDNA obtained after isolating RNA from IEC and mid small intestinal tissue samples.
Immunophenotyping of the small intestinal lamina propia was conducted by flow cytometry.

Results: F2ΔIEC and F2rΔIEC mice showed a decrease in vascular density of small intestinal villus structures. Expression of the vascular markers LYVE1, CD31 and eNOS was downregulated in the small intestine of F2rΔIEC. Additionally, this knockout altered the expression of several genes in the IEC compartment. In contrast, F2rΔEC mice did not show a decreased villus vascularization. Also, epithelial PAR1-deficiency did not affect the abundance of immune cell populations in the gut.

Conclusion(s): Our results indicate that thrombin-dependent PAR1 signaling on the gut epithelium affects small intestinal villus vascularization. This is likely due to PAR1 signaling, since intestinal epithelial thrombin and PAR1-deficiency resulted in reduced vascularization. Taken together, our findings show, that PAR1 signaling in intestinal epithelial cells is involved in vascular remodeling of small intestinal villus capillaries.