KLD12

The number of patients requiring flat bone transplantation continues to increase worldwide. Cell transplantation has been successfully applied clinically; however, it causes another defect site and the time requirements to harvest cells and expand them are considerable. In this study, KLD12/KLD12-SP (KLD12+KLD12-substance P [SP]) was designed to mimic endogenous tissue-healing processes. The structures of KLD12, KLD12-SP, and KLD12/KLD12-SP were observed by transmission electron microscopy and circular dichroism spectra. KLD12/KLD12-SP nanofibers (5-10 nm) were created under physiological conditions by formation of a β-sheet structure. The ability of mesenchymal stem cells (MSCs) to recruit KLD12/KLD12-SP was observed by using an in vivo fluorescence imaging system. Labeled human bone marrow stromal cells supplied via an intravenous injection were recruited to the scaffold containing KLD12/KLD12-SP. Polylactic acid/beta-tricalcium phosphate (PLA/β-TCP) scaffolds filled with KLD12/KLD12-SP were applied to repair calvarial defects. The composite constructs (groups: defect, PLA/β-TCP, PLA/β-TCP/KLD12, and PLA/β-TCP/KLD12/KLD12-SP) were implanted into rat defect sites. Bone tissue regeneration was evaluated by observing gross morphology by hematoxylin and eosin and Masson's trichrome staining at 12 and 24 weeks after surgery. Gross morphology showed that the defect site was filled with new tissue that was integrated with host tissue in the KLD12/KLD12-SP group. In addition, from the staining data, cells were recruited to the defect site and lacunae structures formed in the KLD12/KLD12-SP group. From these results, the PLA/β-TCP+KLD12/KLD12-SP composite construct was considered for enhancement of bone tissue regeneration without cell transplantation.

Objective: This study aimed to evaluate the combination of SDF-1 and KLD-12 to form self-assembling polypeptide and its effect on osteogenic differentiation. Methods: ELISA assay was performed to detect whether KLD-12 composite SDF-1 self-assembled polypeptide was successfully prepared. BMSCs were isolated and characterized by Flow cytometry. MTT assays, Calcein-AM/PI fluorescence staining, and Glycosaminoglycans (GAGs) measurement were carried out to detect cell viability after cells exposed to KLD-12 composite SDF-1 selfassembled polypeptide. The migration of cells induced by KLD-12 composite SDF-1 selfassembled polypeptide was also examined by transwell assay and Immunoblot. Osteogenic differentiation of cells stimulated with KLD-12 composite SDF-1 self-assembled polypeptide was analyzed by Immunoblot, Alizarin Red Staining, and Alkaline Phosphatase activity. Additionally, immunoblot and immunofluorescence assays were performed to investigate the effects of the polypeptide on the Wnt/β-catenin pathway. Results: KLD-12 composite SDF-1 self-assembled polypeptide was successfully prepared and identified. In addition, we isolated and characterized mouse mesenchymal stem BMSCs. Our data further revealed that KLD-12 combined with SDF-1 self-assembled polypeptide improved the survival of BMSCs and promoted cell migration. Moreover, the self-assembled polypeptide induced osteogenic differentiation of BMSCs. Mechanically, we found that the self-assembled polypeptide activated the Wnt/β-catenin pathway, therefore promoting the differentiation and migration of BMSCs. Conclusion: Our proposed treatment can potentially be effective for bone defects.

Intervertebral disc degeneration (IDD) is a common clinical symptom of multifactorial disease. The treatment and expenditure of IDD cause huge economic and psychological harm to patients, and there is no root treatment in the clinic. However, the appearance of tissue engineering materials provides a new idea for the treatment of early IDD. KLD-12 polypeptide material is a new kind of polypeptide scaffold material, which can be used to repair early IDD and TGF-β1Transforming growth factor-1 plays an important role in the proliferation of Intervertebral disc cells and inhibition of inflammatory response. In order to further understand the tissue engineering material kld-12 polypeptide / TGF-β1 the biomechanical properties of nanofiber gel, and to clarify tissue engineering material KLD-12 polypeptide TGF-β1nanofiber gel provides an experimental basis for the protection and mechanism of early IDD. In this paper, tissue engineering material KLD-12 polypeptide /TGF-β1 is mainly studied as the protective effect and mechanism of nanofiber gel on early IDD. In this paper, through the study of the tissue structure of the intervertebral disc, the composition of the nucleus pulposus, annulus fibrosus and cartilage endplate was studied. The objective was to study the relationship between transforming growth factor TGF-β1 and IDD and to understand its important role in the proliferation of intervertebral disc cells and inhibition of inflammatory response. In this paper, we studied the molecular basis of IDD, the main reason is the imbalance of extracellular matrix synthesis and degradation of Intervertebral disc cells, to understand the structural characteristics of cartilage endplate and the composition of Intervertebral disc fibroblasts. In this study, we studied the cell proliferation activity, the ratio of surviving dead cells, the content of glucosaminoglycans, the content of polyproteoglycan and type II collagen in the gel, and studied the protective effect and mechanism of tissue engineering material KLD-12 polypeptide /TGF-β1 nanofiber gel on early IDD. The results showed that kld-12 polypeptide / TGF-β1 was more effective in the proliferation activity of annulus fibrosus cells of nanofiber gel is higher than that of KLD-12 polypeptide/annulus fibroin nanofiber gel. On 2d, the difference in cell proliferation activity was not obvious, KLD-12 polypeptide / TGF- β 1 the fibrous annulus cell proliferation activity of nanofiber gel was 0.796, and the proliferation activity of KLD-12 polypeptide/annulus fibroin nanofiber gel was 0.786. On the 14d, KLD-12 polypeptide / TGF- β 1 the fibrous annulus cell proliferation activity of nanofiber gel was 1.204, and the proliferation activity of KLD-12 polypeptide/annulus fibroin nanofiber gel was 1.034.