Lin28 affects the proliferation and osteogenic differentiation of human dental pulp stem cells by directly inhibiting let-7b maturation.

OBJECTIVE: Activation of Lin28 gene under certain conditions promotes tissue damage repair. However, it remains unknown whether conditional expression of Lin28 facilitates the recovery of damaged pulp tissue. In the study, we focus on exploring the effects and possible regulatory mechanisms of Lin28 on the proliferation and differentiation of human dental pulp stem cells (hDPSCs). MATERIALS AND METHODS: We adopted techniques such as the ethynyl-2'-deoxyuridine (EdU) incorporation assay, RNA-protein immunoprecipitation (RIP) analysis, and luciferase assays to study the regulation of hDPSCs by Lin28. Furthermore, gain-of-function and loss-of-function analyses were also used in explored factors regulating hDPSCs activation. RESULTS: The results show that Lin28 inhibited osteogenic differentiation by directly targets pre-let-7b. Through bioinformatics sequencing and dual luciferase experiments we learned that let-7b directly targets the IGF2BP2 3'UTR. Silencing of IGF2BP2 showed a similar biological effect as overexpression of let-7b. Overexpression of IGF2BP2 counteracted the differentiation-promoting effects produced by let-7b overexpression. DISCUSSION/CONCLUSIONS: In conclusion, the RNA-binding protein Lin28 regulates osteogenic differentiation of hDPSCs by inhibiting let-7 miRNA maturation. And mature let-7b directly regulated the expression of IGF2BP2 by targeting the 3'UTR region of IGF2BP2 mRNA thus further inhibiting the differentiation of hDPSCs.

Separation and purification of flavonoid from Taxus remainder extracts free of taxoids using polystyrene and polyamide resin.

An efficient separation process of flavonoid from Taxus wallichiana var. mairei remainder extracts free of taxoids was developed in this study. AB-8 macroporous resin and polyamide resin offered the fine adsorption capacity, and its adsorption rate at 30°C fitted well to the Langmuir and Freundich isotherms. Resin dynamic adsorption and desorption experiments were conducted to optimize the separation process of total flavonoids from T. wallichiana var. mairei remainder extracts free of taxoids. The optimum parameters for adsorption by AB-8 resin were as follows: (1) the concentration of flavonoids in a sample solution of 5.61 mg/mL with a processing volume of 2 bed volume (BV) (60 mL); (2) for desorption, ethanol-water (80:20, v/v), with 6 BV as an eluent at a flow rate of 2 BV/h. After a one-run treatment with AB-8 resin, the content of flavonoids was increased 5.10-fold from 4.05 to 20.65%. The optimum parameters for adsorption by polyamide resin were as follows: processing volume of 2 BV (30 mL); for desorption, ethanol-water (70:30, v/v), with 8 BV as an eluent at a flow rate of 2 BV/h. After one-run treatment with polyamide resin, the content of total flavonoids increased from 20.65 to 65.21%. The method will provide a potential approach for large-scale separation and purification of flavonoid for its wide pharmaceutical use.

Thermo-responsive Mn-Zn ferrite/poly(N,N'-isopropyl acrylamide-co-N-hydroxymethylacrylamide) core/shell nanocomposites for drug-delivery systems.

A kind of thermo-sensitive core/shell nanoparticles (Mn-Zn ferrite/poly(N,N'-isopropylacrylamide-co-N-hydroxymethylacrylamide)) has been designed in this work. By using the surface initiated method, a thermoresponsive co-polymer composed of N,N'-isopropylacrylamide (NIPAAm) and N-hydroxymethylacrylamide (HMAAm) was grafted from ferrite core. The nanoparticles obtained were characterized by FT-IR, XRD, TGA, HRTEM and DLS. The HRTEM observation showed a clear contrast between an ordered crystalline core and a light amorphous polymeric coating. DLS results confirmed the temperature sensitivity of the nanoparticles. In vitro hyperthermia showed well-controlled self-heating properties, indicating that the nanoparticles could potentially be used as an anticancer drug carrier in the biomedical field.