The regeneration of articular cartilage, which scarcely shows innate self-healing ability, is a great challenge in clinical treatment. Stem cell-derived exosomes (SC-Exos), an important type of extracellular nanovesicle, exhibit great potential for cartilage regeneration to replace stem cell-based therapy. Cartilage regeneration often takes a relatively long time and there is currently no effective administration method to durably retain exosomes at cartilage defect sites to effectively exert their reparative effect. Therefore, in this study, we exploited a photoinduced imine crosslinking hydrogel glue, which presents excellent operation ability, biocompatibility and most importantly, cartilage-integration, as an exosome scaffold to prepare an acellular tissue patch (EHG) for cartilage regeneration. It was found that EHG can retain SC-Exos and positively regulate both chondrocytes and hBMSCs in vitro. Furthermore, EHG can integrate with native cartilage matrix and promote cell deposition at cartilage defect sites, finally resulting in the promotion of cartilage defect repair. The EHG tissue patch therefore provides a novel, cell-free scaffold material for wound repair.

No abstract

No abstract

Schwann cells (SCs) in animals exist in different developmental stages or wound repair phases, distinguished mainly by the expression of SC-specific markers. No study has yet determined SC state under in vitro culture conditions, and the specific markers expressed in SC are obscure as well. In this study, we harvested sciatic nerves from newborn mice and isolated SCs by an enzyme-digestion method, then we examined the expression profiles of ten markers (S100, p75NTR, Sox10, Sox2, GAP43, NCAM, Krox20, Oct6, MBP, and MPZ) at both the RNA and protein levels in in vitro mouse SCs and speculated their relation with in vivo SC stages. We assayed RNA and protein levels of SC specific markers by immunofluorescence, Western Blot, and real-time quantitative RT-PCR. The results show that the expression of most markers (S100, p75NTR, GAP43, NCAM, Krox20, Oct6, MBP and MPZ) was not detectable in all of early stage cultured SCs. The expression of transcription factors Sox10 and Sox2 was, however, detectable in all SCs. After 8 days, the positive expression rate of all markers except GAP43 and Oct6 was almost 100%.These results indicates Sox10 is a necessary marker for SC identification, while S100 is not reliable. SCs cultured in vitro express Sox2, P75NTR, NCAM, GAP43, Oct6, and MPZ, suggesting that they are similar to in vivo undifferentiated iSCs or dedifferentiated iSCs after nerve injury.

In this study, thermosensitive poly(N-isopropylacrylamide) (PNIPAAm) was grafted onto gelatin via atom transfer radical polymerization (ATRP). The chemical structure of PNIPAAm-grafted gelatin (Gel-PNIPAAm) was confirmed by XPS, ATR-IR, and (1)H NMR characterizations. Gel-PNIPAAm aqueous solution exhibited sol-to-gel transformation at physiological temperature, and was studied as injectable hydrogel for bone defect regeneration in a cranial model. The hydrogel was biocompatible and demonstrated the ability to enhance bone regeneration in comparison with the untreated group (control). With the incorporation of rat bone mesenchymal stem cells (BMSCs) into the hydrogel, the bone regeneration rate was further significantly enhanced. As indicated by micro-CT, histological (H&E and Masson) and immunohistochemical (osteocalcin and osteopontin) staining, newly formed woven bone tissue was clearly detected at 12 weeks postimplantation in the hydrogel/BMSCs treated group, showing indistinguishable boundary with surrounding host bone tissues. The results suggested that the thermosensitive Gel-PNIPAAm hydrogel was an excellent injectable delivery vehicle of BMSCs for in vivo bone defect regeneration.

BackgroundDespite advancements in wound healing techniques and devices, new treatments are needed to improve therapeutic outcomes. This study aimed to evaluate the potential use of a new biomaterial engineered from human urine-derived stem cells (USCs) and polycaprolactone/gelatin (PCL/GT) for wound healing.MethodsUSCs were isolated from healthy individuals. To fabricate PCL/GT composite meshes, twin-nozzle electrospinning were used to spin the PCL and gelatin solutions in normal organic solvents. The morphologies and hydrophilicity properties of PCL/GT membranes were investigated. After USCs were seeded onto a PCL/GT, cell adhesion, morphology, proliferation, and cytotoxicity were examined. Then, USCs were seeded on a PCL/GT blend nanofibrous membrane and transplanted into rabbit full-thickness skin defects for wound repair. Finally, the effect of USCs condition medium on proliferation, migration, and tube formation of human umbilical vein endothelial cells (HUVECs) were performed in vitro.ResultsUSCs were successfully isolated from urine samples and expressed specific mesenchymal stem cells markers and could differentiate into osteoblasts, adipocytes, and chondrocytes. PCL/GT membrane has suitable mechanical properties similar with skin tissue and has good biocompatibility. USCs-PCL/GT significantly enhanced the healing of full-thickness skin wounds in rabbits compared to wounds treated with PCL/GT membrane alone or untreated wounds. USCs-PCL/GT-treated wounds closed much faster, with increased re-epithelialization, collagen formation, and angiogenesis. Moreover, USCs could secrete VEGF and TGF-β1, and USC-conditioned medium enhanced the migration, proliferation, and tube formation of endothelial cells.ConclusionUSCs in combination with PCL/GT significantly prompted the healing of full-thickness skin wounds in rabbits. USCs based therapy provides a novel strategy for accelerating wound closure and promoting angiogenesis.

The small p97/VCP-interacting protein (SVIP) functions as an inhibitor of the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway. Here we show that overexpression of SVIP in HeLa cells leads to localization of p97/VCP at the plasma membrane, intracellular foci and juxtanuclear vacuoles. The p97/VCP-positive vacuolar structures colocalized or associated with LC3 and lamp1, suggesting that SVIP may regulate autophagy. In support of this possibility, knockdown of SVIP diminished, whereas overexpression of SVIP enhanced LC3 lipidation. Surprisingly, knockdown of SVIP reduced the levels of p62 protein at least partially through downregulation of its mRNA, which was accompanied by a decrease in starvation-induced formation of p62 bodies. Overexpression of SVIP, on the other hand, increased the levels of p62 protein and enhanced starvation-activated autophagy as well as promoted sequestration of polyubiquitinated proteins and p62 in autophagosomes. These results suggest that SVIP plays a regulatory role in p97 subcellular localization and is a novel regulator of autophagy.

The discovery of induced pluripotent stem cells (iPSCs) rendered the reprogramming of terminally differentiated cells to primary stem cells with pluripotency possible and provided potential for the regeneration and restoration of cartilage defect. Chondrogenic differentiation of iPSCs is crucial for their application in cartilage tissue engineering. In this study we investigated the effect of 3D nanofibrous scaffolds on the chondrogenesis of iPSCs and articular cartilage defect restoration. Super-hydrophilic and durable mechanic polycaprolactone (PCL)/gelatin scaffolds were fabricated using two separate electrospinning processes. The morphological structure and mechanical properties of the scaffolds were characterized. The chondrogenesis of the iPSCs in vitro and the restoration of the cartilage defect was investigated using scanning electron microscopy (SEM), the Cell Counting Kit-8 (CCK-8), histological observation, RT-qPCR, and western blot analysis. iPSCs on the scaffolds expressed higher levels of chondrogenic markers than the control group. In an animal model, cartilage defects implanted with the scaffold-cell complex exhibited an enhanced gross appearance and histological improvements, higher cartilage-specific gene expression and protein levels, as well as subchondral bone regeneration. Therefore, we showed scaffolds with a 3D nanofibrous structure enhanced the chondrogenesis of iPSCs and that iPSC-containing scaffolds improved the restoration of cartilage defects to a greater degree than did scaffolds alone in vivo.