Mangiferin alleviates diabetic pulmonary fibrosis in mice via inhibiting endothelial-mesenchymal transition through AMPK/FoxO3/SIRT3 axis

Diabetes mellitus results in numerous complications. Diabetic pulmonary fibrosis (DPF), a late pulmonary complication of diabetes, has not attracted as much attention as diabetic nephropathy and cardiomyopathy. Mangiferin (MF) is a natural small molecular compound that exhibits a variety of pharmacological effects including anti-inflammatory, anti-cancer, anti-diabetes, and anti-fibrosis effects. In this study, we investigated whether long-term diabetes shock induces DPF, and explored whether MF had a protective effect against DPF. We first examined the lung tissues and sections of 20 diabetic patients obtained from discarded lung surgical resection specimens and found that pulmonary fibrosis mainly accumulated around the pulmonary vessels, accompanied by significantly enhanced endothelial-mesenchymal transition (EndMT). We established a mouse model of DPF by STZ injections. Ten days after the final STZ injection, the mice were administered MF (20, 60 mg/kg, i.g.) every 3 days for 4 weeks, and kept feeding until 16 weeks and euthanized. We showed that pulmonary fibrotic lesions were developed in the diabetic mice, which began around the pulmonary vessels, while MF administration did not affect long-term blood glucose levels, but dose-dependently alleviated diabetes-induced pulmonary fibrosis. In human umbilical vein endothelial cells (HUVECs), exposure to high glucose (33.3 mM) induced EndMT, which was dose-dependently inhibited by treatment with MF (10, 50 μM). Furthermore, MF treatment promoted SIRT3 expression in high glucose-exposed HUVECs by directly binding to AMPK to enhance the activity of FoxO3, which finally reversed diabetes-induced EndMT. We conclude that MF attenuates DPF by inhibiting EndMT through the AMPK/FoxO3/SIRT3 axis. MF could be a potential candidate for the early prevention and treatment of DPF.

Plasmonic nanoparticles embedded in single crystals synthesized by gold ion implantation for enhanced optical nonlinearity and efficient Q-switched lasing

We report on the synthesis of embedded gold (Au) nanoparticles (NPs) in Nd:YAG single crystals using ion implantation and subsequent thermal annealing. Both linear and nonlinear absorption of the Nd:YAG crystals have been enhanced significantly due to the embedded Au NPs, which is induced by the surface plasmon resonance (SPR) effect in the visible light wavelength band. Particularly, through a typical Z-scan system excited by a femtosecond laser at 515 nm within the SPR band, the nonlinear absorption coefficients of crystals with Au NPs have been observed to be nearly 5 orders of magnitude larger than that without Au NPs. This giant enhancement of nonlinear absorption properties is correlated with the saturable absorption (SA) effect, which is the basis of passive Q-switching or mode-locking for pulsed laser generation. In addition, the linear and nonlinear absorption enhancement could be tailored by varying the fluence of implanted Au⁺ ions, corresponding to the NP size and concentration modulation. Finally, the Nd:YAG wafer with embedded Au NPs has been applied as a saturable absorber in a Pr:LuLiF₄ crystal laser cavity, and efficient pulsed laser generation at 639 nm has been realized, which presents superior performance to the MoS₂ saturable absorber based system. This work opens an avenue to enhance and modulate the nonlinearities of dielectrics by embedding plasmonic Au NPs for efficient pulsed laser operation.

Retinoic acid inhibits sodium butyrate-induced monocytic differentiation of HL60 cells while synergistically inducing granulocytoid differentiation

The human myeloid leukemia cell line HL60 is an in vitro model to study myeloid differentiation. HL60 cells differentiate along different cell type lineages in response to a variety of compounds. The direction of differentiation is usually inducer-specific. However, the response of HL60 cells to sodium n-butyrate (NaB) is pleiotropic. NaB induces HL60 along the monocytic, neutrophilic, eosinophilic, and basophilic pathways. In this study we saw that physiologic concentrations of all-trans-retinoic acid (RA) switched the direction of NaB-induced differentiation from monocytic to granulocytic. We showed previously (Breitman & He, Cancer Res 1990: 50: 6268-6273) that combinations of RA and NaB synergistically induce HL60 to cells that reduce nitroblue tetrazolium. The present study shows that this synergy was even greater if the parameter measured was mature granulocytes. Our results raise the possibility that the endogenous RA in the serum used to grow cells in culture may affect the direction of differentiation of HL60 cells induced by NaB. Furthermore, our results may provide additional rationale for the use of combinations of RA and NaB in the treatment of some leukemias.

Combinations of retinoic acid with either sodium butyrate, dimethyl sulfoxide, or hexamethylene bisacetamide synergistically induce differentiation of the human myeloid leukemia cell line HL60

All-trans-retinoic acid (RA), sodium n-butyrate (NaB), hexamethylene bisacetamide (HMBA), and dimethyl sulfoxide (DMSO) induce differentiation of the human acute myeloid leukemia cell line HL60. In the clinic, RA, NaB, or HMBA induce complete or partial remissions. However, the achievement and maintenance of effective plasma concentrations and toxicity have been problems. These difficulties led us to study the interaction of RA with these inducers. We found that combinations of RA with either NaB, HMBA, or DMSO synergistically induced terminal differentiation of HL60. A measure of the effectiveness of these combinations was that the doses of NaB, HMBA, and DMSO required alone to induce half-maximal differentiation were decreased about 4-fold in combination with normal plasma concentrations of about 30 nM RA. RA or NaB alone did not enhance the growth of HL60 cells. In contrast, HMBA or DMSO alone increased growth of HL60 cells even at concentrations that did not induce differentiation. The addition of RA reduced the promotion of growth and increased the extent of terminal differentiation seen with HMBA and DMSO alone. These data suggest that treatment of some malignancies with combinations of RA with HMBA or NaB may maintain differentiation-inducing effects and decrease the problems associated with the achievement and maintenance of effective plasma concentrations as single agents.