FIBROBLAST ACTIVATION PROTEIN IS OVEREXPRESSED IN INFLAMED INTESTINAL MUCOSA AND MAY BE MODULATED BY MIR-21

ANAHÍ E. RENDÓN SORIA; EMANUEL BARBIERA ROMERO; MALENA FERREYRA COMPAGNUCCI; MARIA BELÉN POLO; MANUELA ILLID; ANDRÉS ROCCA; ALICIA SAMBUELLI; JUAN ARRIOLA; MARÍA BELÉN SARACHO; KARINA COLLIA; MARÍA VIRGINIA GENTILIN; GABRIEL GONDOLESSI; GUSTAVO J. CORREA; MARTÍN YANTORNO; MARÍA VICTORIA GARCÍA MERCADER; MARTÍN RUMBO; GUILLERMO H. DOCENA; CECILIA I. MUGLIA; RENATA CURCIARELLO

San Luis

Congreso; Reunión Anual de la Sociedad Argentina de Inmunología (SAI); 2023

Fibroblast activation protein (FAP) is a transmembrane endopeptidase presentin cancer associated fibroblasts, which contributes to extracellular matrixremodeling and mesenchymal cell activation, favoring tumoral growth. FAPoverexpression has been reported in lung and breast cancer, under microRNA21 (miR-21) regulation. Nevertheless, FAP role is not completely described incolorectal cancer (CRC). We previously showed miR-21 overexpression ininflammatory bowel disease (IBD) patients´ mucosa and intestinal fibroblasts.IBD is a predisposing condition for CRC development; we aim to investigate FAPexpression in the colonic mucosa of patients with chronic intestinal inflammation.Colonic biopsies and surgical samples were taken from macroscopicallyinflamed and uninflamed mucosa from patients with IBD, CRC, polyps, orhealthy controls (HC). Mucosal pieces were fixed and staining for FAP and αSMA was performed by indirect immunofluorescence (IF). Total RNA wasextracted from mucosal samples, and retro-transcribed. qPCR was performedon cDNA using specific primers for miR-21, fap, α-sma and HPRT. Relativeexpression was normalized to U6 for miRNA or to HPRT for the rest, and datawere analyzed using the comparative threshold method (2−ΔCt). Fibroblastprimary cultures were established after isolating lamina propria cells bymechanical and enzymatic digestion of biopsies or tissue sections. Cells werecultured in DMEM Glutamax 20% FBS with antibiotics. Fibroblast culturesupernatants were collected and ultracentrifuged at 100.000xg for 2 h forexosome enrichment, which were visualized by atomic force microscopy. MiR21 expression was evaluated by qPCR in cells and exosome fractions. In vitroinduction of FAP was evaluated on fibroblasts by IF, after stimulation with TGFβ (1 and 10 ng/ml) or exosomal fraccion for 24 h. Images were acquired withLeica SP5 confocal microscope. FAP and α-SMA merge images were analyzedwith Image J and QuPath softwares.We observed an overexpression of miR-21 and its target genes in the intestinalmucosa and fibroblasts from IBD and CRC patients, compared to HC (p