Background: Platelet-rich plasma (PRP) has been considered a promising tool for cartilage regeneration. However, increasing evidence has demonstrated the controversial effects of PRP on tissue regeneration, partially due to the unsatisfactory cell source. Chondrogenic progenitor cells (CPCs) have gained increasing attention as a potential cell source due to their self-renewal and multipotency, especially toward the chondrogenic lineage, and, thus, may be an appropriate alternative for cartilage engineering. Purpose: To compare the effects of PRP on CPC, mesenchymal stem cell (MSC), and chondrocyte proliferation, chondrogenesis, and cartilage regeneration. Study Design: Controlled laboratory study. Methods: Whole blood samples were obtained from 5 human donors to create PRPs (0, 1000 × 109, and 2000 × 109 platelets per liter). The proliferation and chondrogenesis of CPCs, bone marrow–derived MSCs (BMSCs), and chondrocytes were evaluated via growth kinetic and CCK-8 assays. Immunofluorescence, cytochemical staining, and gene expression analyses were performed to assess chondrogenic differentiation and cartilaginous matrix formation. The in vivo effects of CPCs, BMSCs, and chondrocytes on cartilage regeneration after PRP treatment were measured by use of histopathological, biochemical, and biomechanical techniques in a cartilage defect model involving mature male New Zealand White rabbits (critical size, 5 mm). Results: The CPCs possessed migration abilities and proliferative capacities superior to those of the chondrocytes, while exhibiting a chondrogenic predisposition stronger than that of the BMSCs. The growth kinetic, CCK-8, cytochemical staining, and biochemical analyses revealed that the CPCs simultaneously displayed a higher cell density than the chondrocytes and stronger chondrogenesis than the BMSCs after PRP stimulation. In addition, the in vivo study demonstrated that the PRP+CPC construct yielded better histological (International Cartilage Repair Society [ICRS] score, mean ± SEM, 1197.2 ± 163.2) and biomechanical (tensile modulus, 1.523 ± 0.194) results than the PRP+BMSC (701.1 ± 104.9, P < .05; 0.791 ± 0.151, P < .05) and PRP+chondrocyte (541.6 ± 98.3, P < .01; 0.587 ± 0.142, P < .01) constructs at 12 weeks after implantation. Conclusion: CPCs exhibit superiority over MSCs and chondrocytes in PRP scaffold-based cartilage regeneration, and PRP+CPC treatment may be a favorable strategy for cartilage repair. Clinical Relevance: These findings provide evidence highlighting the preferable role of CPCs as a cell source in PRP-mediated cartilage regeneration and may help researchers address the problem of unsatisfactory cell sources in cartilage engineering.

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HLA-DR -CD11b + CD33 + MDSCs were then evaluated and the results revealed that they express high CD13 and CD39, and low CD115, CD117, CD124 and programmed cell death ligand 1; they were also devoid of CD14, CD15 and CD66b. MDSCs and T-cells from peripheral blood were sorted by flow cytometry for co-culture experiments. Lin -/low HLA-DR -CD11b + CD33 + MDSCs from patients significantly inhibited the proliferation of CD4 and CD8 T-cells. Furthermore, functional analysis verified that MDSCs from cervical cancer patients could inhibit interleukin-2 and interferon-γ production from T-cells. In addition, the associations between peripheral circulating MDSCs and tumor infiltrating MDSCs, and tumor relapse and metastasis were analyzed. The number of peripheral MDSCs and MDSCs in tumor tissue were observed to be associated with relapse-free survival. Thus, MDSCs in the peripheral blood and tumors of cervical cancer patients have a significant immunosuppressive effect, and are associated with cervical cancer staging and metastasis. These results suggest that targeting MDSCs may increase antitumor immunity and increase the efficacy of cervical cancer therapies.

The effect of shading during seed development on subsequent germination remains largely unknown. In this study, two soybean (Glycine max) seed production systems, monocropping (MC) and maize–soybean intercropping (IC), were employed to examine the effects of shading of the mother plant on subsequent seed germination. Compared to the MC soybean seeds, which received light, the developing IC seeds were exposed to shade resulting from the taller neighboring maize plants. The IC seeds germinated faster than the MC seeds, although there was no significant difference in the thickness of the seed coat. The concentration of soluble pro-anthocyanidin in the IC seed coat was significantly lower than that in the MC seed coat. Changes in the concentrations of several types of fatty acids in IC seeds were also observed, the nature of which were consistent with the effect on germination. The expression levels of genes involved in abscisic acid (ABA) biosynthesis were down-regulated in IC seeds, while the transcription levels of the genes related to gibberellin (GA) biosynthesis were up-regulated. This was consistently reflected in decreased ABA concentrations and increased active GA4 concentrations in IC seeds, resulting in an increased GA4/ABA ratio. Our results thus indicated that shading of the mother plant during seed development in soybean promoted subsequent germination by mediating the biosynthesis of pro-anthocyanidins, fatty acids, and phytohormones.

Gibberellins (GAs) promote secondary cell wall (SCW) development in plants, but the underlying molecular mechanism is still to be elucidated. Here, we employed a new system, the first internode of cotton, and the virus-induced gene silencing method to address this problem. We found that knocking down major DELLA genes via VIGS phenocopied GA treatment and significantly enhanced SCW formation in the xylem and phloem of cotton stems. Cotton DELLA proteins were found to interact with a wide range of SCW-related NAC proteins, and virus-induced gene silencing of these NAC genes inhibited SCW development with downregulated biosynthesis and deposition of lignin. The findings indicated a framework for the GA regulation of SCW formation; that is, the interactions between DELLA and NAC proteins mediated GA signaling to regulate SCW formation in cotton stems.