Fibroblast Activation Protein is overexpressed in inflamed intestinal mucosa and may be induced by upregulation of microRNA-21

ANAHÍ RENDÓN SORIA; EMANUEL BARBIERA ROMERO; ANTONIA DOMINGUEZ; MALENA FERREYRA COMPAGNUCCI; MARÍA BELEN POLO; EMANUEL LLANQUIMAN; LAURA UDABE; ANDRÉS ROCCA; ALICIA MARÍA SAMBUELLI; MARÍA BELÉN SARACHO; KARINA COLLIA; MARÍA VIRGINIA GENTILINI; GABRIEL GONDOLESSI; GUSTAVO J. CORREA; MARTÍN YANTORNO; MARIA VICTORIA MERCADER; JULIO DE MARÍA; MARTIN, RUMBO; GUILLERMO HORACIO DOCENA; MARJORIE DE LA FUENTE; GLAUBEN LANDSKRON; CECILIA ISABEL MUGLIA; RENATA CURCIARELLO

Copenague

Congreso; International Congress of Mucosal Immunology 2024; 2024

Society for Mucosal Immunology

Fibroblast activation protein (FAP), a transmembraneendopeptidase of cancer fibroblasts, and microRNA-21 (miR-21) are markedlyincreased in several tumours. FAP correlates with poor prognosis in colorectalcancer (CRC), suggesting it as a putative biomarker and therapeutic target.Here we investigated FAP expression in Inflammatory Bowel Disease (IBD), themain chronic predisposing condition for CRC development. Colonic biopsies and surgical samples were taken fromIBD, CRC and healthy individuals. FAP and α-SMA were evaluated by indirectimmunofluorescence (IF) on formalin-fixed paraffin embedded tissue (tissuemicroarray). Fibroblast primary cultures were established after mechanical andenzymatic digestion of tissue samples. Total RNAseq was performed forfibroblast lines. MiR-21, FAP and ACTA2 were quantified by qPCR inbiopsies and fibroblasts. Culture supernatants were ultracentrifuged forexosome enrichment (visualised by atomic force microscopy), and miR-21expression was analysed in exosomes. Invitro induction of FAP was evaluated in fibroblasts by IF, afterstimulation with TGF-β or exosomal fractions. We found overexpression of miR-21, FAP and ACTA2 in mucosa and fibroblasts from IBD and CRC patients, and bothproteins were localised in the stroma of these mucosal samples. TGF-β andmiR-21-rich-exosomal fractions induced FAP expression in fibroblast primarycultures in vitro. Total RNAseq ofIBD fibroblasts revealed differential expression of protein pathways andupregulation of miRNAs, mainly related to extracellular matrix remodelling andfibrosis.MiR-21 overexpression in chronic inflamed mucosa mayinduce fibroblasts activation pathways. Understanding the role and interplay ofmiRNAs and proteins which predispose to CRC in IBD, will improve preventive andtherapeutic strategies.