A novel splice variant of human TGF-beta type II receptor encodes a soluble protein and its Fc-tagged version prevents liver fibrosis in vivo.

MARCELA SOLEDAD BERTOLIO; ANABELA LA COLLA; ALEJANDRA CARREA; ANA ROMO; GABRIELA CANZIANI; STELLA MARIS ECHARTE; SABRINA EDITH CAMPISANO; GERMAN PATRICIO BARLETTA; ALEXANDER MONZON; TANIA MELINA RODRÍGUEZ; ANDREA NANCY CHISARI; RICARDO A. DEWEY

Frontiers in Cell and Developmental Biology

Frontiers Media S.A.

Lugar: Lausanne; Año: 2021 vol. 9 p. 1 - 15

2296-634X

We describe, for the first time, a new splice variant of the human TGF-β type II receptor (TβRII). The new transcript lacks 149 nucleotides, resulting in a frameshift and the emergence of an early stop codon, rendering a truncated mature protein of 57 amino acids. The predicted protein, lacking the transmembrane domain and with a distinctive 13 amino acid stretch at its C-terminus, was named TβRII-Soluble Endogenous (TβRII-SE). Binding predictions indicate that the novel 13 amino acid stretch interacts with all three TGF-β cognate ligands and generates a more extensive protein-protein interface than TβRII. TβRII-SE and human IgG1 Fc-domain, were fused in frame in a lentiviral vector (Lv) for further characterization. With this vector, we transduced 293T cells and purified TβRII-SE/Fc by A/G protein chromatography from conditioned medium. Immunoblotting revealed homogeneous bands of approximately 37 kDa (reduced) and 75 kDa (non-reduced), indicating that TβRII-SE/Fc is secreted as a disulphide-linked homodimer. Moreover, high affinity binding of TβRII-SE to the three TGF-β isoforms was confirmed by Surface Plasmon Resonance (SPR) analysis. Also, intrahepatic delivery of Lv.TβRII-SE/Fc in a carbon tetrachloride-induced liver fibrosis model revealed amelioration of liver injury and fibrosis. Our results indicate that TβRII-SE is a novel member of the TGF-β signaling pathway with distinctive characteristics. This novel protein offers an alternative for the prevention and treatment of pathologies caused by the overproduction of TGF-β ligands.