[Research progress of knee meniscal repair techniques].

Objective: To review the research progress of meniscus repair in recent years, in order to provide help for the clinical decision-making of meniscus injury treatment. Methods: The domestic and foreign literature related to meniscal repair in recent years was extensively reviewed to summarize the reasons for the prevalence of meniscal repair, surgical indications, various repair methods and long-term effectiveness, the need to deal with mechanical structural abnormalities, biological enhancement repair technology, rehabilitation treatment, and so on. Results: In order to delay the occurrence of osteoarthritis, the best treatment of meniscus has undergone an important change from partial meniscectomy to meniscal repair, and the indications for meniscal repair have been expanding. The mid- and long-term effectiveness of different meniscal repair methods are ideal. During meniscus repair, the abnormality of lower limb force line and meniscus protrusion should be corrected at the same time. There are controversies about the biological enhancement technology to promote meniscus healing and rehabilitation programs, which need further study. Conclusion: Meniscal repair can restore the normal mechanical conduction of lower limbs and reduce the incidence of traumatic osteoarthritis, but the poor blood supply and healing ability of meniscal tissue bring difficulties to meniscal repair. Further development of new biological enhanced repair technology and individualized rehabilitation program and verification of its effectiveness will be an important research direction.

Cytosine-phosphate-guanine oligodeoxynucleotides regulate the cell cycle, apoptosis, and steroidogenesis of mouse ovarian granulosa cells by targeting inhibin alpha (1 ~ 32) fragments.

Cytosine-phosphate-guanine oligodeoxynucleotides (CpG-ODNs), which exist in vertebrate, bacterial, and viral genomes, are regarded as strong immune adjuvants. To date, the biological activities of CpG-ODNs in reproduction remain unknown. Here, we investigated the effects of CpG-ODNs on the cell cycle, apoptosis, and steroidogenesis in mouse granulosa cells (mGCs), in combination with inhibin alpha (1 ~ 32) fragments. mGCs were transfected with pEGFP (containing green fluorescent protein, as a control), pEGISI (containing inhibin alpha (1 ~ 32) fragments), or pEGISI-CpG-ODNs (containing inhibin alpha (1 ~ 32) fragments and CpG-ODNs motifs) plasmid for 48 h in vitro. Our results showed that the mRNA and protein expression levels of inhibin alpha were downregulated in mGCs transfected with pEGISI-CpG-ODNs, compared to those transfected with pEGISI. Flow cytometry demonstrated that pEGISI-CpG-ODNs transfection promoted cell proliferation (for example, increasing the number of cells in S and G2 phases) and decreased apoptosis, compared to pEGISI transfection. The present study also indicated that the expression of cell cycle-related genes (cyclin D2, cyclin D3, cyclin E1, Cdk2, and Cdk6) was increased, while the expression of apoptosis-related factors (Fas, FasL, caspase-8, and caspase-3) decreased after pEGISI-CpG-ODNs treatment. Additionally, pEGISI-CpG-ODNs reversed the effect of pEGISI on the secretion of estradiol in mGCs, which was further validated by upregulating the levels of its synthesis-related factors (StAR, Cyp11a1, and 17ß-HSD II). Nevertheless, pEGISI-CpG-ODNs or pEGISI did not affect the concentration of progesterone nor changed the expression levels of its synthesis-related factors (3ß-HSD I and Cyp19a1). In conclusion, this study demonstrated that CpG-ODNs may affect the cell cycle, apoptosis, and steroidogenesis by targeting the effects of inhibin alpha (1 ~ 32) fragments, supporting the potential role of CpG-ODNs in the development of granulosa cells.

MgFe-LDH Nanoparticles: A Promising Leukemia Inhibitory Factor Replacement for Self-Renewal and Pluripotency Maintenance in Cultured Mouse Embryonic Stem Cells.

Leukemia inhibitory factor (LIF), an indispensable bioactive protein that sustains self-renewal and pluripotency in stem cells, is vital for mouse embryonic stem cell (mESC) culture. Extensive research is conducted on reliable alternatives for LIF as its clinical application in stable culture and large-scale expansion of ESCs is limited by its instability and high cost. However, few studies have sought to replace LIF with nanoparticles to provide a xeno-free culture condition. MgAl-LDH (layered double hydroxide) nanoparticles can partially replace LIF in maintaining pluripotency of mESCs; however, the requirement and tolerance for aluminum ions in mice are far lesser than those of iron ions. Hence, MgFe-LDH nanoparticles are selected for this study. MgFe-LDH is superior to MgAl-LDH in maintaining self-renewal and pluripotency of mESCs, in the absence of LIF and mouse embryonic fibroblast. Furthermore, combined transcriptomic and proteomic analysis confirms that MgFe-LDH can activate the LIF receptor (LIFR)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B(AKT), LIFR/JAK/janus kinase (JAK)/signal transducer and activator of transcription 3(STAT3), and phospho-signal transducer and activator of transcription 3(p-STAT3)/ten-eleven translocation (TET) signaling pathways, while the extra Fe2+ provided by MgFe-LDH would also enhance TET1/2 abundance thus affecting the TET1/2 regulated pluripotency related marker expression and TET1/2 meditated DNA demethylation. These results suggest that MgFe-LDH nanoparticles can thus be used as an affordable and efficient replacement for LIF in mESC cultivation.

Unexpected anomeric selectivity of a 1-C-arylglycal donor in Kdo glycoside synthesis.

A novel class of 1-C-arylglycals was developed and subjected to N-iodosuccinimide-mediated glycosylations with alcohols. Unexpectedly, all reactions provided 2-iodo-ß-D-ketopyranosides in high yields and excellent stereoselectivity. After removal of the 2-iodide by radical conditions, the aryl group was smoothly oxidized to provide the corresponding ß-Kdo glycosides. A mechanism for the stereoselective formation of ß-D-ketopyranosides was proposed, which was supported by evidence from X-ray crystallography.

Synthesis of a Forssman antigen derivative for use in a conjugate vaccine.

The total chemical synthesis of a Forssman antigen analog is described. The pentasaccharide contains a functionalized tether which should facilitate future conjugation with immunogenic proteins. We found that the total synthesis can be efficiently achieved by following a convergent 2+3 strategy, and using N-Troc protected GalNAc thioglycoside as a donor.

An efficient conversion of N-acetyl-D-glucosamine to N-acetyl-D-galactosamine and derivatives.

2-Acetamido-2-deoxy-D-galactose (d-GalNAc) is an important monosaccharide widely distributed in nature. However, unlike its 4-epimer, the 2-acetamido-2-deoxy-D-glucose (D-GlcNAc), D-GalNAc is very expensive to obtain from commercial sources. Herein we report an efficient transformation that allows for the conversion of D-GlcNAc to a D-GalNAc derivative 7 in three steps and in 58.4-75% overall yields. The process was carried out on a greater than 20-g scale without the need of chromatography. The versatility of compound 7 was demonstrated by the synthesis of several useful monosaccharides and thiodisaccharides containing a D-GalNAc residue.