High quality repair of osteochondral defects in rats using the extracellular matrix of antler stem cells.

BACKGROUND: Cartilage defects are some of the most common causes of arthritis. Cartilage lesions caused by inflammation, trauma or degenerative disease normally result in osteochondral defects. Previous studies have shown that decellularized extracellular matrix (ECM) derived from autologous, allogenic, or xenogeneic mesenchymal stromal cells (MSCs) can effectively restore osteochondral integrity. AIM: To determine whether the decellularized ECM of antler reserve mesenchymal cells (RMCs), a xenogeneic material from antler stem cells, is superior to the currently available treatments for osteochondral defects. METHODS: We isolated the RMCs from a 60-d-old sika deer antler and cultured them in vitro to 70% confluence; 50 mg/mL L-ascorbic acid was then added to the medium to stimulate ECM deposition. Decellularized sheets of adipocyte-derived MSCs (aMSCs) and antlerogenic periosteal cells (another type of antler stem cells) were used as the controls. Three weeks after ascorbic acid stimulation, the ECM sheets were harvested and applied to the osteochondral defects in rat knee joints. RESULTS: The defects were successfully repaired by applying the ECM-sheets. The highest quality of repair was achieved in the RMC-ECM group both in vitro (including cell attachment and proliferation), and in vivo (including the simultaneous regeneration of well-vascularized subchondral bone and avascular articular hyaline cartilage integrated with surrounding native tissues). Notably, the antler-stem-cell-derived ECM (xenogeneic) performed better than the aMSC-ECM (allogenic), while the ECM of the active antler stem cells was superior to that of the quiescent antler stem cells. CONCLUSION: Decellularized xenogeneic ECM derived from the antler stem cell, particularly the active form (RMC-ECM), can achieve high quality repair/reconstruction of osteochondral defects, suggesting that selection of decellularized ECM for such repair should be focused more on bioactivity rather than kinship.

Discovery of tetrahydroisoquinolineindole derivatives as first dual PRMT5 inhibitors/hnRNP E1 upregulators: Design, synthesis and biological evaluation.

Protein arginine methyltransferase 5 (PRMT5) is an epigenetics related enzyme that has been validated as an important therapeutic target for treating various types of cancer. Upregulation of tumor suppressor hnRNP E1 has also been considered as an effective antitumor therapy. In this study, a series of tetrahydroisoquinolineindole hybrids were designed and prepared, and compounds 3m and 3s4 were found to be selective inhibitors of PRMT5 and upregulators of hnRNP E1. Molecular docking studies indicated that compounds 3m occupied the substrate site of PRMT5 and formed essential interactions with amino acid residues. Furthermore, compounds 3m and 3s4 exerted antiproliferative effects against A549 cells by inducing apoptosis and inhibiting cell migration. Importantly, silencing of hnRNP E1 eliminated the antitumor effect of 3m and 3s4 on the apoptosis and migration in A549 cells, suggesting a regulatory relationship between PRMT5 and hnRNP E1. Additionally, compound 3m exhibited high metabolic stability on human liver microsomes (T1/2 = 132.4 min). In SD rats, the bioavailability of 3m was 31.4%, and its PK profiles showed satisfactory AUC and Cmax values compared to the positive control. These results suggest that compound 3m is the first class of dual PRMT5 inhibitor and hnRNP E1 upregulator that deserves further investigation as a potential anticancer agent.

Studies of high-membered two-dimensional Ruddlesden-Popper Cs7Pb6I19 perovskite nanosheets via kinetically controlled reactions.

Two-dimensional (2D) all-inorganic Ruddlesden-Popper (RP) perovskite Cs7Pb6I19 nanosheets (NSs) were successfully developed for the first time by employing a structural recrystallization process with additional passivation of small organic sulfide molecules. The structure of Cs7Pb6I19 NSs is confirmed by powder X-ray diffraction measurements, atomically-resolved STEM measurements and atomic force microscopy (AFM) studies. Cs7Pb6I19 NSs with a specific n value of 6 exhibits unique absorption and emission spectra with intense excitons at 560 nm due to quantum confinement effects in 2D perovskite slabs. The formation mechanisms of 2D Cs7Pb6I19 NSs and 3D γ-CsPbI3 phases were investigated by in situ photoluminescence (PL) spectroscopy and the activation energies of their formation reactions were calculated to be 151 kJ mol-1 and 95.3 kJ mol-1, respectively. The phase stability of 2D Cs7Pb6I19 NSs can be maintained at temperatures below 14 °C for more than 4 weeks. The overall results indicate that 2D Cs7Pb6I19 NSs demonstrate unique optical properties and structural stability compared with other 3D perovskite materials. We have opened a new path to the future discovery of 2D perovskite structures with metastable phases by using this recrystallization method and the assistance of sulfur-derived organic molecules.

Expression and Functional Analysis of Tumor-Related Factor S100A4 in Antler Stem Cells.

Annual antler renewal is a stem cell-based epimorphic process driven by antler stem cells (ASCs) resident in antlerogenic periosteum (AP). Antlerogenic periosteal cells express a high level of S100A4, a metastasis-associated protein, which intrigued us to explore what role S100A4 could play in antler regeneration. The present study set out to investigate expression and effects of S100A4 in the ASCs and their progeny. The results showed that not only did cells from the AP express a high level of S100A4, but also the pedicle periosteum and the antler growth center. In the antler growth center, we found S100A4-positive cells were specifically located in blood vessel walls and in vascularized areas. In vitro, recombinant deer S100A4 protein stimulated the proliferation of the AP cells, promoted proliferation, migration and tube formation of human vascular endothelial cells, and enhanced migration of Hela cells, but not AP cells. These findings demonstrated that S100A4 in the ASCs may play a significant role in stimulating angiogenesis, proliferation, but not motility, of ASCs. Deer antlers offer a unique model to explore how rapid cell proliferation with a high level of S100A4 expression is elegantly regulated without becoming cancerous.

Analysis of Genomewide DNA Methylation Reveals Differences in DNA Methylation Levels between Dormant and Naturally as well as Artificially Potentiated Pedicle Periosteum of Sika Deer (Cervus nippon).

Deer antlers are the only mammalian appendages that can fully regenerate each year from the permanent bony protuberances of the frontal bones, called pedicles. Pedicle periosteum (PP) is the key tissue for antler regeneration and the source of antler stem cells. The distal one third of the PP has acquired the ability to regenerate antlers and is termed the potentiated PP (PPP), whereas the proximal two thirds of the PP requires further interactions within its niche to launch antler regeneration and is termed the dormant PP (DPP). However, the molecular mechanisms underlying the process of potentiation from the DPP to the PPP are unknown. In this study, we used the fluorescence-labeled methylation-sensitive amplified polymorphism method to assess the levels of DNA methylation in both cells and tissues of the PPP and the DPP. The results showed that the levels of DNA methylation were significantly lower in the PPP compared to the DPP (P < 0.05). Therefore, DNA demethylation may be involved in the process of this potentiation. This involvement was further confirmed by functional testing by artificially creating a potentiated PP (aPPP) from DPP tissue. Moreover, we identified 15 methylated fragments by the methylation sensitive amplified polymorphism method that are either unique to the PPP or the DPP, which were further confirmed by Southern blot analysis. Taken together, our data suggest that DNA demethylation is involved in the process of PP potentiation, which is a prerequisite step for the initiation of antler regeneration. These findings provide the first experimental evidence to link epigenetic regulation and mammalian appendage regeneration.