Highly Effective Crosslinker for Redox-Sensitive Gene Carriers

Polyethyleneimine (PEI) has been extensively used as a common gene carrier due to its high gene transfection efficiency. PEI1.8k shows significantly lower cytotoxicity than its high molecular weight counterparts. However, it also has the problem of low gene transfection efficiency. To address the dilemma, a highly effective crosslinker (DTME) was synthesized to react with PEI1.8k to obtain CS-PEI1.8k. The reaction showed several advantages, such as a fast process in room temperature within nine hours with the product which can directly complex with DNA after removing the solvent. The ability of CS-PEI1.8k to agglomerate with DNA was proven by particle size, zeta potential, and gel retardation assays. The cytotoxic in vitro transfection ability and cell internalization capacity of CS-PEI1.8k were tested to verify the transfection capacity of CS-PEI1.8k. Moreover, we also studied the mechanism of the relatively high level of gene transfection by this binary complex compared with PEI25k.

Hypoglycemic and Hypolipidemic Effects of a Novel Pan-Peroxisome Proliferator-Activated Receptor Agonist, MBT1805, in db/db Mices

Background: MBT1805 is a novel pan-Peroxisome Proliferator-Activated Receptor (PPAR) agonist. Materials and Methods: In vitro, transfection and luciferase assays tested EC50 values of MBT1805. In vivo, hypoglycemic and hypolipidemic effects of MBT1805 were observed in db/db mice compared with Rosiglitazone. Results: In vitro, MBT1805 activates human PPARα, PPARγ and PPARδ with EC50 values of 8.46μM, 11.94μM, 11.15μM, respectively. Results showed that the bodyweight of db/db mice treated with MBT1805 was not changed. By contrast, Rosiglitazone-treated mice showed significant weight gain (p<0.05). MTB1805 decreased blood glucose level without causing noticeable hepatocytes damage. Conclusion: The novel balanced pan-PPAR agonist, MBT1805 has moderate hypoglycemic and hypolipidemic effects, and does not cause weight gain, hepatocyte damage and hepatic lipid deposition. These experimental results indicate that MBT1805 is safe in the treatment of type 2 diabetes.

Chitosan-miRNA functionalized microporous titanium oxide surfaces via a layer-by-layer approach with a sustained release profile for enhanced osteogenic activity

Background The biofunctionalization of titanium implants for high osteogenic ability is a promising approach for the development of advanced implants to promote osseointegration, especially in compromised bone conditions. In this study, polyelectrolyte multilayers (PEMs) were fabricated using the layer-by-layer approach with a chitosan-miRNA (CS-miRNA) complex and sodium hyaluronate (HA) as the positively and negatively charged polyelectrolytes on microarc-oxidized (MAO) Ti surfaces via silane-glutaraldehyde coupling. Methods Dynamic contact angle and scanning electron microscopy measurements were conducted to monitor the layer accumulation. RiboGreen was used to quantify the miRNA loading and release profile in phosphate-buffered saline. The in vitro transfection efficiency and the cytotoxicity were investigated after seeding mesenchymal stem cells (MSCs) on the CS-antimiR-138/HA PEM-functionalized microporous Ti surface. The in vitro osteogenic differentiation of the MSCs and the in vivo osseointegration were also evaluated. Results The surface wettability alternately changed during the formation of PEMs. The CS-miRNA nanoparticles were distributed evenly across the MAO surface. The miRNA loading increased with increasing bilayer number. More importantly, a sustained miRNA release was obtained over a timeframe of approximately 2 weeks. In vitro transfection revealed that the CS-antimiR-138 nanoparticles were taken up efficiently by the cells and caused significant knockdown of miR-138 without showing significant cytotoxicity. The CS-antimiR-138/HA PEM surface enhanced the osteogenic differentiation of MSCs in terms of enhanced alkaline phosphatase, collagen production and extracellular matrix mineralization. Substantially enhanced in vivo osseointegration was observed in the rat model. Conclusions The findings demonstrated that the novel CS-antimiR-138/HA PEM-functionalized microporous Ti implant exhibited sustained release of CS-antimiR-138, and notably enhanced the in vitro osteogenic differentiation of MSCs and in vivo osseointegration. This novel miRNA-functionalized Ti implant may be used in the clinical setting to allow for more effective and robust osseointegration.