Vitamin D receptor (VDR) on the cell membrane of mouse macrophages participates in the formation of lipopolysaccharide tolerance: mVDR is related to the effect of artesunate to reverse LPS tolerance.

It is unclear whether membrane vitamin D receptor (mVDR) exists on the macrophage membrane or whether mVDR is associated with lipopolysaccharide (LPS) tolerance. Herein, we report that interfering with caveolae and caveolae-dependent lipid rafts inhibited the formation of LPS tolerance. VDR was detected as co-localized with membrane molecular markers. VDR was detected on the cell membrane and its level was higher in LPS-tolerant cells than that in only LPS treatment cells. Anti-VDR antibodies could abolish the effect of artesunate (AS) to reverse LPS tolerance, and the wild-type peptides (H397 and H305) of VDR, but not the mutant peptide (H397D and H305A), led to the loss of AS's effect. AS decreased the mVDR level in LPS-tolerant cells. In vivo, AS significantly reduced VDR level in the lung tissue of LPS-tolerant mice. In summary, mVDR exists on the cell membrane of macrophages and is closely associated with the formation of LPS tolerance and the effects of AS. Video Abstract.

Low-Intensity Pulsed Ultrasound Promotes Osteogenic Potential of iPSC-Derived MSCs but Fails to Simplify the iPSC-EB-MSC Differentiation Process.

Induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (iMSCs) are a promising cell source for bone tissue engineering. However, iMSCs have less osteogenic potential than BMSCs, and the classical iPSC-EB-iMSC process to derive iMSCs from iPSCs is too laborious as it involves multiple in vitro steps. Low-intensity pulsed ultrasound (LIPUS) is a safe therapeutic modality used to promote osteogenic differentiation of stem cells. Whether LIPUS can facilitate osteogenic differentiation of iMSCs and simplify the iPSC-EB-iMSC process is unknown. We stimulated iMSCs with LIPUS at different output intensities (20, 40, and 60 mW/cm2) and duty cycles (20, 50, and 80%). Results of ALP activity assay, osteogenic gene expression, and mineralization quantification demonstrated that LIPUS was able to promote osteogenic differentiation of iMSCs, and it worked best at the intensity of 40 mW/cm2 and the duty cycle of 50% (LIPUS40/50). The Wnt/ß-catenin signaling pathway was involved in LIPUS40/50-mediated osteogenesis. When cranial bone defects were implanted with iMSCs, LIPUS40/50 stimulation resulted in a significant higher new bone filling rate (72.63 ± 17.04)% than the non-stimulated ones (34.85 ± 4.53)%. Daily exposure to LIPUS40/50 may accelerate embryoid body (EB)-MSC transition, but it failed to drive iPSCs or EB cells to an osteogenic lineage directly. This study is the first to demonstrate the pro-osteogenic effect of LIPUS on iMSCs. Although LIPUS40/50 failed to simplify the classical iPSC-EB-MSC differentiation process, our preliminary results suggest that LIPUS with a more suitable parameter set may achieve the goal. LIPUS is a promising method to establish an efficient model for iPSC application.

Artesunate protects immunosuppression mice induced by glucocorticoids via enhancing pro-inflammatory cytokines release and bacterial clearance.

Glucocorticoids are commonly used in clinic, but the immunosuppression seriously hinders their usage. Herein, immunomodulatory effect of artesunate (AS) on hydrocortisone (HC)-induced immunosuppression was investigated. HC-induced immunosuppression mice (HC mice) were established by intramuscular administration with HC (20 mg/kg) once a day for 5 consecutive days. The results showed HC mice challenged with Escherichia coli on the sixth day presented a lower ability to clear bacteria, decreased TNF-α in blood, decreased spleen index and thymus index. Significantly, AS (20 mg/kg) treatment not only enhanced the ability of HC mice to clear bacteria, but also increased spleen index, the levels of pro-inflammatory cytokines from 78.7 ± 12.1 ng/ml (TNF-α) and 48.7 ± 8.6 pg/ml (IL-6) to 174.0 ± 90.5 ng/ml and 783.3 ± 90.5 pg/ml, number of white blood cells in blood, and sIgA in colon. Subsequently, HC-induced immunosuppression peritoneal macrophages model (HC cells) was established via addition of HC (0.5 µg/ml) for 0.5 h, and then LPS (100 ng/ml) was added to clarify the functional status of the cells. The results showed HC inhibited TNF-α and IL-6 mRNA expressions and their release, but AS (2.5 µg/ml) could increase TNF-α and IL-6 mRNA expressions and their release. AS inhibited GILZ mRNA up-regulated by HC and increases TLR4/NF-κB p65 expressions down-regulated by HC. Our findings revealed that AS's effect is closely related to the improvement of the TLR4/NF-κB signal transduction pathway via inhibiting the up-regulation of GILZ mRNA, demonstrating AS does possess immunomodulatory effects and is worth further investigation in the future.

A graphene oxide-gold nanostar hybrid based-paper biosensor for label-free SERS detection of serum bilirubin for diagnosis of jaundice.

We report a paper-based surface-enhanced Raman spectroscopy (SERS) biosensor integrating the enrichment capability, namely enPSERS biosensor, for the sensitive, label-free detection of free bilirubin in blood serum for the accurate diagnosis of jaundice and its related diseases. This biosensor comprises multifunctional graphene oxide-plasmonic gold nanostar (GO-GNS) hybrids decorated on the filter paper, which integrates the high sensitivity of SERS detection, enrichment for serum bilirubin and fluorescence superquenching capability of GO-GNS hybrids for sensitive detection of serum bilirubin. The study of adsorption kinetics reveals that both electrostatic and π-π interactions between the GO-GNS hybrids and targets are responsible for the enrichment of bilirubin, and the adsorption process follows the pseudo-second-order kinetic model. The results of SERS detection of bilirubin in blood serum show two differential linear response ranges from 5.0 to 150 µM and 150-500 µM with the detection limit as low as 0.436 µM. The comparison of the results obtained from our present enPSERS biosensor with the commercial diazo reaction method for determination of free bilirubin in blood serum reveals the clinical effectiveness and suitability of the developed paper-based SERS biosensor. We believe that this sensitive and label-free SERS biosensor holds considerable promise for clinical translation in accurate diagnosis of jaundice.

In Situ Raman Spectroscopic Studies of Thermal Stability of All-Inorganic Cesium Lead Halide (CsPbX3, X = Cl, Br, I) Perovskite Nanocrystals.

Thermal degradation becomes the main obstacle for industrial applications of all-inorganic cesium lead halide (CsPbX3, X = Cl, Br, I) perovskite optoelectronic devices. A complete understanding of thermal degradation of CsPbX3 perovskites is required but greatly challenging for achieving optoelectronic devices with long-term stability, particularly under extreme settings. Herein, we present an in situ spectroscopic study of thermal stability of CsPbX3 nanocrystals between the cryogenic temperature and high temperature. The low-frequency Raman signatures of CsPbX3 nanocrystals dramatically evolve but differentiate from the halogen atoms at elevated temperatures, acting as potent indicators of their crystalline structures and phase transitions. The merging of doublet Raman bands of CsPbX3 nanocrystals indicates their high-temperature phase transitions. CsPbX3 (X = Br, I) nanocrystals undergo a state of high degree of disorder with featureless Raman spectra before being thermally decomposed. Such understanding is of particular importance for future design and optimization of high-performance CsPbX3 perovskite devices with long-term stability under extreme settings.

Surface-enhanced Raman spectroscopy (SERS) nanoprobes for ratiometric detection of cancer cells.

We report a ratiometric strategy for detection of different types of breast cancer cells by surface-enhanced Raman spectroscopy (SERS), which simultaneously quantifies the levels of dual biomarkers distinctly expressed on cancer cells to consequently achieve their expression ratio. Two SERS nanoprobes that are encoded with distinct SERS signatures are conjugated with urokinase plasminogen activation receptor (uPAR)- and epidermal growth factor receptor (EGFR)-targeting peptides. The SERS imaging of single live cells can accurately quantify the cellular biomarker expression difference from the SERS intensity ratio and is further employed for cancer cell screening. The results show that MDA-MB-231 and MCF-7 exhibit distinct expression of the uPAR and EGFR and they can be respectively discriminated by the intensity ratio of SERS signals from uPAR- and EGFR-targeting SERS nanoprobes. The ratiometric strategy permits background-free SERS detection of cancer cells and dramatically improves the signal-to-noise ratio of targeted cellular SERS imaging, thus enabling accurate cancer cell screening without the need for additional references. It is believed that the present ratiometric method should be a promising avenue for breast cancer diagnostics and screening, which can be easily extended for detection of other cancer cell types.