Donor Muse Cell Treatment Without HLA-Matching Tests and Immunosuppressant Treatment.

The strength of stem cell therapy is the regeneration of tissues by synergistic pleiotropic effects. Among many stem cell types, mesenchymal stem cells (MSCs) that are comprised of heterogenous population are widely used for clinical applications with the expectation of pleiotropic bystander effects. Muse cells are pluripotent-like/macrophage-like stem cells distributed in the bone marrow, peripheral blood, and organ connective tissues as cells positive for the pluripotent surface marker stage-specific-embryonic antigen -3. Muse cells comprise ~1% to several percent of MSCs. While Muse cells and MSCs share several characteristics, such as mesenchymal surface marker expression and their bystander effects, Muse cells exhibit unique characteristics not observed in MSCs. These unique characteristics of Muse cells include selective homing to damaged tissue after intravenous injection rather than being trapped in the lung like MSCs, replacement of a wide range of damaged/apoptotic cells by differentiation through phagocytosis, and long-lasting immunotolerance for donor cell use. In this review, we focus on the basic properties of Muse cells clarified through preclinical studies and clinical trials conducted by intravenous injection of donor-Muse cells without HLA-matching tests or immunosuppressant treatment. MSCs are considered to differentiate into osteogenic, chondrogenic, and adipogenic cells, whereas the range of their differentiation has long been debated. Muse cells may provide clues to the wide-ranging differentiation potential of MSCs that are observed with low frequency. Furthermore, the utilization of Muse cells may provide a novel strategy for clinical treatment.

Mechanical convergence in mixed populations of mammalian epithelial cells.

Tissues consist of cells with different molecular and/or mechanical properties. Measuring the forces and stresses in mixed-cell populations is essential for understanding the mechanisms by which tissue development, homeostasis, and disease emerge from the cooperation of distinct cell types. However, many previous studies have primarily focused their mechanical measurements on dissociated cells or aggregates of a single-cell type, leaving the mechanics of mixed-cell populations largely unexplored. In the present study, we aimed to elucidate the influence of interactions between different cell types on cell mechanics by conducting in situ mechanical measurements on a monolayer of mammalian epithelial cells. Our findings revealed that while individual cell types displayed varying magnitudes of traction and intercellular stress before mixing, these mechanical values shifted in the mixed monolayer, becoming nearly indistinguishable between the cell types. Moreover, by analyzing a mixed-phase model of active tissues, we identified physical conditions under which such mechanical convergence is induced. Overall, the present study underscores the importance of in situ mechanical measurements in mixed-cell populations to deepen our understanding of the mechanics of multicellular systems.

Wnt activation disturbs cell competition and causes diffuse invasion of transformed cells through NF-κB-MMP21 pathway.

Normal epithelial cells exert their competitive advantage over RasV12-transformed cells and eliminate them into the apical lumen via cell competition. However, the internal or external factors that compromise cell competition and provoke carcinogenesis remain elusive. In this study, we examine the effect of sequential accumulation of gene mutations, mimicking multi-sequential carcinogenesis on RasV12-induced cell competition in intestinal epithelial tissues. Consequently, we find that the directionality of RasV12-cell extrusion in Wnt-activated epithelia is reversed, and transformed cells are delaminated into the basal lamina via non-cell autonomous MMP21 upregulation. Subsequently, diffusively infiltrating, transformed cells develop into highly invasive carcinomas. The elevated production of MMP21 is elicited partly through NF-κB signaling, blockage of which restores apical elimination of RasV12 cells. We further demonstrate that the NF-κB-MMP21 axis is significantly bolstered in early colorectal carcinoma in humans. Collectively, this study shows that cells with high mutational burdens exploit cell competition for their benefit by behaving as unfit cells, endowing them with an invasion advantage.

Accumulation of annexin A2 and S100A10 prevents apoptosis of apically delaminated, transformed epithelial cells.

In various epithelial tissues, the epithelial monolayer acts as a barrier. To fulfill its function, the structural integrity of the epithelium is tightly controlled. When normal epithelial cells detach from the basal substratum and delaminate into the apical lumen, the apically extruded cells undergo apoptosis, which is termed anoikis. In contrast, transformed cells often become resistant to anoikis and able to survive and grow in the apical luminal space, leading to the formation of multilayered structures, which can be observed at the early stage of carcinogenesis. However, the underlying molecular mechanisms still remain elusive. In this study, we first demonstrate that S100A10 and ANXA2 (Annexin A2) accumulate in apically extruded, transformed cells in both various cell culture systems and murine epithelial tissues in vivo. ANXA2 acts upstream of S100A10 accumulation. Knockdown of ANXA2 promotes apoptosis of apically extruded RasV12-transformed cells and suppresses the formation of multilayered epithelia. In addition, the intracellular reactive oxygen species (ROS) are elevated in apically extruded RasV12 cells. Treatment with ROS scavenger Trolox reduces the occurrence of apoptosis of apically extruded ANXA2-knockdown RasV12 cells and restores the formation of multilayered epithelia. Furthermore, ROS-mediated p38MAPK activation is observed in apically delaminated RasV12 cells, and ANXA2 knockdown further enhances the p38MAPK activity. Moreover, the p38MAPK inhibitor promotes the formation of multilayered epithelia of ANXA2-knockdown RasV12 cells. These results indicate that accumulated ANXA2 diminishes the ROS-mediated p38MAPK activation in apically extruded transformed cells, thereby blocking the induction of apoptosis. Hence, ANXA2 can be a potential therapeutic target to prevent multilayered, precancerous lesions.

Phase III clinical trial of autologous CD34 + cell transplantation to accelerate fracture nonunion repair.

BACKGROUND: We previously demonstrated that CD34 + cell transplantation in animals healed intractable fractures via osteogenesis and vasculogenesis; we also demonstrated the safety and efficacy of this cell therapy in an earlier phase I/II clinical trial conducted on seven patients with fracture nonunion. Herein, we present the results of a phase III clinical trial conducted to confirm the results of the previous phase studies using a larger cohort of patients. METHODS: CD34 + cells were mobilized via administration of granulocyte colony-stimulating factor, harvested using leukapheresis, and isolated using magnetic cell sorting. Autologous CD34 + cells were transplanted in 15 patients with tibia nonunion and 10 patients with femur nonunion, who were followed up for 52 weeks post transplantation. The main outcome was a reduction in time to heal the tibia in nonunion patients compared with that in historical control patients. We calculated the required number of patients as 15 based on the results of the phase I/II study. An independent data monitoring committee performed the radiographic assessments. Adverse events and medical device failures were recorded. RESULTS: All fractures healed during the study period. The time to radiological fracture healing was 2.8 times shorter in patients with CD34 + cell transplantation than in the historical control group (hazard ratio: 2.81 and 95% confidence interval 1.16-6.85); moreover, no safety concerns were observed. CONCLUSIONS: Our findings strongly suggest that autologous CD34 + cell transplantation is a novel treatment option for fracture nonunion. TRIAL REGISTRATION: UMIN-CTR, UMIN000022814. Registered on 22 June 2016.

Secukinumab-induced oral lichen planus in a psoriatic arthritis patient ameliorated after a switch to risankizumab.

Lichen planus is a chronic T-cell-mediated disorder in which lymphocytes, including Th17 cells, react toward the dermo-epidermal junction, which shows interface changes. Recently, IL-17-mediated changes in the oral mycobiome, including the proliferation of Candida and Aspergillus fungi, have been proposed as a possible pathomechanism of oral lichen planus (OLP). We treated a 54-year-old male who had been suffering from psoriatic arthritis. Secukinumab rapidly improved the skin and joint symptoms, but a painful erosion on the lip and thrush on the buccal mucosa appeared within 4 weeks. The erosion was histopathologically diagnosed as OLP. Although the candidiasis was successfully treated with topical miconazole nitrate, the labial OLP worsened during the secukinumab administration, despite the application of various topical agents. We finally switched from secukinumab to risankizumab, an anti-IL-23p19 agent, which dramatically improved the patient's OLP lesion in 4 weeks without candidiasis recurrence. Anti-IL-23p19 agents do not affect the oral mycobiome, and they are a potential therapeutic option for refractory OLP, including OLP induced by biologics.