Restoration of cellular function of mesenchymal stem cells from a hypophosphatasia patient

Abstract

Mesenchymal stem cells (MSCs) can differentiate into multiple cell lineages and are used for regenerative treatments for a variety of diseases. However, the patient's cells cannot be used to treat genetic diseases. Allogeneic cells can serve as an alternative but long-term survival is uncertain. Our experience of allo-transplantation to a patient with hypophosphatasia, which is caused by mutations of the tissue non-specific alkaline phosphatase (TNSALP) gene resulting in low serum alkaline phosphatase (ALP) activity and skeletal deformity, did not improve these clinical characteristics. Therefore, we sought to use autologous MSCs for the treatment of hypophosphatasia. MSCs derived from the patient's bone marrow had a similar profile when compared with well-reported MSCs. However, the MSCs had extremely low ALP activity and could not produce a mineralized bone matrix even under the osteogenic culture conditions. We therefore transduced a retroviral vector with TNSALP promoter-driven TNSALP gene in the MSCs. In the culture condition, the MSCs had about 7-fold higher ALP activity than did mock-transduced MSCs, and showed mineralization as well as bone-specific markers. Furthermore, the MSCs, but not mock-transduced MSCs, newly formed bone at the frequency of 50% in nude rats. Transplantation of the TNSALP-transduced autologous MSCs might become a new therapy for hypophosphatasia.

Molecular characterization of tissue-nonspecific alkaline phosphatase with an Ala to Thr substitution at position 116 associated with dominantly inherited hypophosphatasia

“…There is no established medical treatment for hypophosphatasia. However, several attempts have recently been made to aim at developing the cure for this rare disease [24][25][26]. Especially, an enzyme replacement therapy using a soluble human recombinant TNSALP with a bone-targeted deca-aspartate motif is promising [24] and The specific activity was expressed in unit mg -1 protein.…”

Alkaline Phosphatase Controls Lineage Switching of Mesenchymal Stem Cells by Regulating the LRP6/GSK3β Complex in Hypophosphatasia

“…However, according to a recent study, targeted deletion of Alpl in osteoblasts (Col1a1-Cre) and mesenchymal cells (Prx1-Cre, used to delete genes from mesenchymal progenitor cells) both phenocopy the skeletal and dental deformities of HPP 22 . Notably, BMMSCs isolated from patients with HPP exhibit extremely low ALP activity and diminished osteogenic differentiation 23 . Since TNSALP is expressed at high levels on the BMMSC membrane 4 , 24 , we hypothesize that TNSALP may regulate the function of BMMSCs and subsequently affect bone characteristics 4 , 24 .…”

A dimerization defect caused by a glycine substitution at position 420 by serine in tissue‐nonspecific alkaline phosphatase associated with perinatal hypophosphatasia

“…There have been increasing attempts to develop a clinical treatment for HPP including ex vivo and in vivo gene therapy [27][28][29][30][31][32][33][34][35][36][37][38]. Among these, enzyme replacement therapy using a soluble form of recombinant TNSALP attached with a bone-targeted motif has been extensively studied in an animal model of HPP [33][34][35][36] and successfully applied to HPP patients [37,38] (http://clinicaltrials.gov/).…”