Research Paper|Volume 13, Issue 23|pp 25055—25071

IGFBP-6/sonic hedgehog/TLR4 signalling axis drives bone marrow fibrotic transformation in primary myelofibrosis

Lucia Longhitano¹, Daniele Tibullo¹, Nunzio Vicario¹, Cesarina Giallongo², Enrico La Spina³, Alessandra Romano³, Sofia Lombardo⁴, Marina Moretti⁵, Francesco Masia⁵, Anna Rita Daniela Coda⁶, Santina Venuto⁶, Paolo Fontana⁴, Rosalba Parenti¹, Giovanni Li Volti¹, Michelino Di Rosa¹, Giuseppe A. Palumbo², Arcangelo Liso⁶

¹Department of Biomedical and Biotechnological Sciences, University of Catania, Catania 95123, Italy
²Department of Scienze Mediche Chirurgiche e Tecnologie Avanzate “G.F. Ingrassia”, University of Catania, Catania 95123, Italy
³Division of Hematology, Department of General Surgery and Medical-Surgical Specialties, A.O.U. “Policlinico-Vittorio Emanuele”, University of Catania, Catania 95123, Italy
⁴Department of Medical Oncology, The Mediterranean Institute of Oncology, Viagrande 95029, Italy
⁵Department of Medicine, University of Perugia, Perugia 06129, Italy
⁶Department of Medical and Surgical Sciences, University of Foggia, Foggia 71100, Italy

* Co-first author

# Co-last author

Received: August 3, 2021Accepted: December 3, 2021Published: December 14, 2021

https://doi.org/10.18632/aging.203779

Copyright: © 2021 Longhitano et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Primary myelofibrosis is a Ph-negative chronic myeloproliferative neoplasm characterized by bone marrow fibrosis and associated with the involvement of several pathways, in addition to bone marrow microenvironment alterations, mostly driven by the activation of the cytokine receptor/JAK2 pathway. Identification of driver mutations has led to the development of targeted therapy for myelofibrosis, contributing to reducing inflammation, although this currently does not translate into bone marrow fibrosis remission. Therefore, understanding the clear molecular cut underlying this pathology is now necessary to improve the clinical outcome of patients. The present study aims to investigate the involvement of IGFBP-6/sonic hedgehog /Toll-like receptor 4 axis in the microenvironment alterations of primary myelofibrosis. We observed a significant increase in IGFBP-6 expression levels in primary myelofibrosis patients, coupled with a reduction to near-normal levels in primary myelofibrosis patients with JAK2V617F mutation. We also found that both IGFBP-6 and purmorphamine, a SHH activator, were able to induce mesenchymal stromal cells differentiation with an up-regulation of cancer-associated fibroblasts markers. Furthermore, TLR4 signaling was also activated after IGFBP-6 and purmorphamine exposure and reverted by cyclopamine exposure, an inhibitor of the SHH pathway, confirming that SHH is involved in TLR4 activation and microenvironment alterations. In conclusion, our results suggest that the IGFBP-6/SHH/TLR4 axis is implicated in alterations of the primary myelofibrosis microenvironment and that IGFBP-6 may play a central role in activating SHH pathway during the fibrotic process.