Fibroblast-specific antifibrotic drug delivery for intestinal fibrosis using precision-cut human intestinal slices

Overview

This research platform addresses the urgent need for cell-specific therapies to treat intestinal fibrosis, a major complication of Crohn's disease. The project combines three complementary areas of expertise to develop and validate drug carriers that selectively deliver antifibrotic compounds to activated fibroblasts in fibrotic intestinal tissue.

The approach builds on two decades of validated work demonstrating that cell-specific drug carriers targeting receptors such as PDGF receptor-beta and IGF-II receptor can effectively accumulate in activated fibroblasts in fibrotic liver, kidney, and tumor tissues. These targeted carriers have consistently shown superior efficacy compared to untargeted drugs in animal models. The platform now extends this strategy to intestinal fibrosis by leveraging precision-cut intestinal slices (PCIS) prepared from surgical material of Crohn's disease patients, along with a unique collection of more than 70 primary human intestinal fibroblast cell lines derived from fibrotic and non-fibrotic tissues.

Technical specifications

Drug carrier design:

• Cell-specific protein-based carriers ranging from 9 to 90 kDa in size
• Targeting of PDGF receptor-beta and IGF-II receptor on activated fibroblasts
• Fluorescent labeling (Alexa) for tracking binding and uptake
• Compatibility with antifibrotic drug conjugation

Precision-cut intestinal slices (PCIS):

• In-house developed platform with world-leading expertise
• Prepared from surgical material of fibrotic and non-fibrotic Crohn's disease patients
• Optimized culture conditions maintaining viability over 3 to 5 days, verified by ATP assays
• Supports analysis of fibrotic processes via qPCR, Western blotting, immunohistochemistry, and pro-collagen ELISA

Primary human fibroblast cell lines:

• Collection of more than 70 lines derived from non-fibrotic and fibrotic human intestinal tissues
• Phenotyped by qPCR and subdivided by collagen expression (fibrotic) and IL13RA2 expression (inflammatory)
• Characterized for target receptor expression including PDGF receptor-beta

Validation read-outs:

• Flow cytometry (Cytoflex) for quantitative binding and uptake measurements
• Confocal fluorescence microscopy for cellular localization
• Receptor specificity confirmation using trapidil, a PDGF receptor-beta antagonist
• Immunohistochemistry and immunofluorescence for tissue-level distribution

Technology readiness level

The core technologies are well established. Cell-specific drug carriers targeting PDGF receptors have been validated in vitro in fibroblast cell lines (NIH-3T3) and in vivo in mouse and rat liver fibrosis models (CCL4, bile duct ligation), a mouse renal fibrosis model, and tumor-bearing mice, with prior organ distribution, cellular localization, and antifibrotic efficacy studies completed. The PCIS platform and the primary human intestinal fibroblast collection have been optimized and characterized in previous work.

The current project represents the translational step applying these validated carriers to human intestinal tissue. Initial experiments will test Alexa-labeled carriers in fibroblast cultures to confirm receptor-specific binding and uptake, followed by evaluation in fibrotic and non-fibrotic PCIS to determine optimal carrier size, concentration, and time point conditions for fibroblast-specific accumulation in human intestinal tissue.