Crosstalk between bone and brain in Alzheimer's disease: Mechanisms, applications, and perspectives.

Alzheimer's disease (AD) is a neurodegenerative disease that involves multiple systems in the body. Numerous recent studies have revealed bidirectional crosstalk between the brain and bone, but the interaction between bone and brain in AD remains unclear. In this review, we summarize human studies of the association between bone and brain and provide an overview of their interactions and the underlying mechanisms in AD. We review the effects of AD on bone from the aspects of AD pathogenic proteins, AD risk genes, neurohormones, neuropeptides, neurotransmitters, brain-derived extracellular vesicles (EVs), and the autonomic nervous system. Correspondingly, we elucidate the underlying mechanisms of the involvement of bone in the pathogenesis of AD, including bone-derived hormones, bone marrow-derived cells, bone-derived EVs, and inflammation. On the basis of the crosstalk between bone and the brain, we propose potential strategies for the management of AD with the hope of offering novel perspectives on its prevention and treatment. HIGHLIGHTS: The pathogenesis of AD, along with its consequent changes in the brain, may involve disturbing bone homeostasis. Degenerative bone disorders may influence the progression of AD through a series of pathophysiological mechanisms. Therefore, relevant bone intervention strategies may be beneficial for the comprehensive management of AD.

Mesenchymal stem cells regulate mechanical properties of human degenerated nucleus pulposus cells through SDF-1/CXCR4/AKT axis.

Transplantation of mesenchymal stem cells (MSCs) into the degenerated intervertebral disc (IVD) has shown promise for decelerating or arresting IVD degeneration. Cellular mechanical properties play crucial roles in regulating cell-matrix interactions, potentially reflecting specific changes that occur based on cellular phenotype and behavior. However, the effect of co-culturing of MSCs with nucleus pulposus cells (NPCs) on the mechanical properties of NPCs remains unknown. In our study, we demonstrated that co-culture of degenerated NPCs with MSCs resulted in significantly decreased mechanical moduli (elastic modulus, relaxed modulus, and instantaneous modulus) and increased biological activity (proliferation and expression of matrix genes) in degenerated NPCs, but not normal NPCs. SDF-1, CXCR4 ligand, was highly expressed in MSCs when co-cultured with degenerated NPCs. Inhibition of SDF-1 using CXCR4 antagonist AMD3100 or knocking-down CXCR4 in degenerated NPCs abolished the MSCs-induced decrease in the mechanical moduli and increased biological activity of degenerated NPCs, suggesting a crucial role for SDF-1/CXCR4 signaling. AKT and FAK inhibition attenuated the MSCs- or SDF-1-induced decrease in the mechanical moduli of degenerated NPCs. In conclusion, it was demonstrated in vitro that MSCs regulate the mechanical properties of degenerated NPCs through SDF-1/CXCR4/AKT signaling. These findings highlight a possible mechanical mechanism for MSCs-induced modulation with degenerated NPCs, which may be applicable to MSCs-based therapy for disc degeneration.

Strong metal-support interactions between gold nanoparticles and ZnO nanorods in CO oxidation.

The catalytic performances of supported gold nanoparticles depend critically on the nature of support. Here, we report the first evidence of strong metal-support interactions (SMSI) between gold nanoparticles and ZnO nanorods based on results of structural and spectroscopic characterization. The catalyst shows encapsulation of gold nanoparticles by ZnO and the electron transfer between gold and the support. Detailed characterizations of the interaction between Au nanoparticles and ZnO were done with transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), electron paramagnetic resonance (EPR), and FTIR study of adsorbed CO. The significance of the SMSI effect is further investigated by probing the efficiency of CO oxidation over the Au/ZnO-nanorod. In contrast to the classical reductive SMSI in the TiO(2) supported group VIII metals which appears after high temperature reduction in H(2) with electron transfer from the support to metals, the oxidative SMSI in Au/ZnO-nanorod system gives oxygen-induced burial and electron transfer from gold to support. In CO oxidation, we found that the oxidative SMSI state is associated with positively charged gold nanoparticles with strong effect on its catalytic activity before and after encapsulation. The oxidative SMSI can be reversed by hydrogen treatment to induce AuZn alloy formation, de-encapsulation, and electron transfer from support to Au. Our discovery of the SMSI effects in Au/ZnO nanorods gives new understandings of the interaction between gold and support and provides new way to control the interaction between gold and the support as well as catalytic activity.

Dipole field guided orientated attachment of nanocrystals to twin-brush ZnO mesocrystals.

Mesocrystals of ZnO were synthesized hydrothermally by using gum arabic as a structure-directing agent. Their hierarchical structure has a unique twin-brush form consisting of vertically aligned nanorods in a single-crystal-like porous form. The formation mechanism of the twin-brush ZnO was investigated by quenching a series of samples at different times and examining them by TEM, SEM, and XRD. The alignment of ZnO crystal units can be modulated by adding simple salts such as KCl to change the units from nanorods to nanoplates. This can be explained by screening the dipolar force of the polar crystal. Local cathodoluminescence of twin-brush ZnO was used to follow the local structure changes.

Id2 exerts tumor suppressor properties in lung cancer through its effects on cancer cell invasion and migration.

Background: Despite advances in prognosis and treatment of lung adenocarcinoma (LADC), a notable non-small cell lung cancer subtype, patient outcomes are still unsatisfactory. New insight on novel therapeutic strategies for LADC may be gained from a more comprehensive understanding of cancer progression mechanisms. Such strategies could reduce the mortality and morbidity of patients with LADC. In our previous study, we performed cDNA microarray screening and found an inverse relationship between inhibitor of DNA binding 2 (Id2) expression levels and the invasiveness of LADC cells. Materials and Methods: To identify the functional roles of Id2 and its action mechanisms in LADC progression, we successfully established several Id2-overexpressing and Id2-silenced LADC cell clones. Subsequently, we examined in vitro the effects exerted by Id2 on cell morphology, proliferation, colony formation, invasive, and migratory activities and examined in vivo those exerted by Id2 on cell metastasis. The mechanisms underlying the action of Id2 were investigated using RNA-seq and pathway analyses. Furthermore, the correlations of Id2 with its target gene expression and clinical outcomes were calculated. Results: Our data revealed that Id2 overexpression could inhibit LADC cells' migratory, invasive, proliferation, and colony formation capabilities. Silencing Id2 expression in LADC cells reversed the aforementioned inhibitory effects, and knockdown of Id2 increased LADC cells' metastatic abilities in vivo. Bioinformatics analysis revealed that these effects of Id2 on cancer progression might be regulated by focal adhesion kinase (FAK) signaling and CD44/Twist expression. Furthermore, in online clinical database analysis, patients with LADC whose Id2 expression levels were high and FAK/Twist expression levels were low had superior clinical outcomes.Conclusion: Our data indicate that the Id2 gene may act as a metastasis suppressor and provide new insights into LADC progression and therapy.

Tiny Ni particles dispersed in platelet SBA-15 materials induce high efficiency for CO2 methanation.

In this study, short-channel SBA-15 with a platelet morphology (p-SBA-15) is used to support Ni to effectively enhance catalytic activity and CH4 selectivity during CO2 hydrogenation. The use of p-SBA-15 as a support can result in smaller Ni particle sizes than Ni particles on typical SBA-15 supports because p-SBA-15 possesses a larger surface area and a greater ability to provide metal-support interactions. The Ni/p-SBA-15 materials with tiny Ni particles exhibit enhanced catalytic activity toward CO2 hydrogenation and CH4 formation during CO2 hydrogenation compared to the same Ni loading on a SBA-15 support. The presence of metal-support interaction on the Ni/p-SBA-15 catalyst may increase the possibility of abundance of strongly adsorbing sites for CO and CO2, thus resulting in high reaction rates for CO2 and CO hydrogenation. The reaction kinetics, reaction pathway and active sites were studied and correlated to the high catalytic activity for CO2 hydrogenation to form CH4.

Autophagy mediates serum starvation-induced quiescence in nucleus pulposus stem cells by the regulation of P27.

BACKGROUND: Adult stem cells exist in a quiescent state (G0) within the in vivo niche; the loss of quiescence often leads to a decrease in the number and function of adult stem cells, impairing tissue regeneration and repair. Endogenous repair by nucleus pulposus-derived stem cells has recently shown promising regenerative potential for the treatment of intervertebral disc degeneration (IDD). However, the number and function of nucleus pulposus stem cells (NPSCs) declined throughout the process of IDD. This effect may have a specific relationship with quiescence. However, the biology of the quiescent NPSCs has not been reported. METHODS: First, we established an in vitro model for NPSC quiescence with serum starvation. The induction of G0 was confirmed by flow cytometry analyses of dual staining with Hoechst 33342 and Pyronin Y, immunofluorescent staining with Ki67 and Western blot analysis of P27 expression. NPSCs were cultured under serum starvation conditions for a long time period (21 days). To examine the functional phenotype of quiescent NPSCs, the cells were reactivated with 10% serum and differentiated into osteogenic and chondrogenic lineages in vitro. The number of colony-forming units was also estimated. To elucidate the role of autophagy in the quiescence of NPSCs, we activated and inhibited autophagy in starved cells with rapamycin and chloroquine, respectively. Then, the expression of P27 was evaluated by Western blot analysis, and the immunofluorescence of Ki67 was assessed. Finally, we assessed the role of P27 siRNA in NPSC quiescence by flow cytometry analyses and 5-ethynyl-20-deoxyuridine incorporation assays under normal and serum-starved conditions. RESULTS: NPSC quiescence was induced by 48 h of serum starvation, and they maintained quiescence for up to 21 days. Upon reactivation with serum, the quiescent NPSCs re-entered the cell cycle and exhibited enhanced clonogenic self-renewal, osteogenic differentiation and chondrogenic differentiation potentials compared to control NPSCs under normal culture conditions. We also found that autophagy underlay serum starvation-induced NPSC quiescence. Further study demonstrated that autophagy mediated the quiescence of NPSCs by regulating P27. CONCLUSIONS: Serum starvation efficiently induces quiescence in NPSCs. Quiescent NPSCs maintain stem cell properties. Our study reveals that autophagy plays a role in maintaining NPSC quiescence and that autophagy mediates the quiescence of NPSCs by regulating P27. We conclude that the induction of quiescence in cultured NPSCs provides a useful model for the analysis of mechanisms that might be relevant to the biology of NPSCs in vivo.

Cellular mechanical properties reflect the differentiation potential of nucleus pulposus-derived progenitor cells.

Mechanical properties of cells reflect differences in cellular subpopulations, differentiation potency, and cell behaviors. Previous study has revealed that intervertebral disc (IVD) degeneration leads to alterations in cell behavior and differentiation potency. Human nucleus pulposus-derived progenitor cells (NPPCs) are an attractive cell sources for IVD regeneration. However, the relationship between mechanical properties and differentiation potential in different NPPC subpopulations is few known. In this study, mechanical properties of different NPPC subpopulations were measured via atomic force microscopy (AFM) and correlated with differentiation potential of NPPCs. We found that elastic modulus, relaxed modulus, and instantaneous modulus were positively correlated with osteogenic potential of NPPCs. And apparent viscosity was correlated with chondrogenic potential of NPPCs. These results indicated that the mechanical properties were predictive markers for differentiation potential of NPPC subpopulations, and could be used for enrichment based on differentiation potential, which could significantly improve the outcome of IVD regeneration.

Elevated ASCL2 expression is associated with metastasis of osteosarcoma and predicts poor prognosis of the patients.

Achaetescute-like 2 (ASCL2), a basic helix-loop-helix (bHLH) transcription factor, plays an important role in the determination of neuronal precursors in the central and peripheral nervous system and involves in tumor progression. However, the role of ASCL2 expression in the osteosarcoma prognosis has not been elaborated. This study aimed to evaluate ASCL2 expression level in osteosarcoma and assess its prognostic value for patients. ASCL2 protein expression was detected by immunohistochemistry (IHC) in 73 cases of osteosarcoma. Kaplan-Meier analysis and Cox regression analysis were performed to evaluate the prognostic significance of ASCL2. Immunohistochemistry analysis showed that the overall survival and metastasis-free survival of patients with positive ASCL2 expression were significantly shorter than patients with negative expression (both P<0.01). Multivariate Cox analysis identified ASCL2 expression as an independent prognostic factor to predict poor overall survival and metastasis-free survival (both P<0.01). Overexpression of ASCL2 expression greatly promoted cell proliferation and enhanced migration and invasion in vitro. This study indicates that increased expression of ASCL2 in primary osteosarcoma is a novel biomarker for predicting the development of metastases and poor outcomes of the patients.

Downregulation of Semaphorin-3F is associated with poor prognostic significance in osteosarcoma patients.

The secreted axonal guidance molecular, Semaphorin-3F (SEMA3F), is widely expressed outside the central nervous system and inhibits tumor growth and metastasis. However, the role of SEMA3F expression in the osteosarcoma prognosis has not been elaborated. This study aimed to evaluate SEMA3F expression level in osteosarcoma and assess its prognostic value for patients. SEMA3F protein expression was detected by immunohistochemistry (IHC) in 112 cases of osteosarcoma. Kaplan-Meier analysis and Cox regression analysis were performed to evaluate the prognostic significance of SEMA3F. The results showed that the overall survival and metastasis-free survival of patients with negative SEMA3F expression were significantly shorter than patients with positive expression (both P<0.01). Multivariate Cox analysis identified SEMA3F expression as an independent prognostic factor to predict favorable overall survival and metastasis-free survival (both P<0.01). When endogenous SEMA3F expression was knocked down by siRNAs, cell proliferation, colony formation, migration and invasion in osteosarcoma cell lines were obviously promoted. Meanwhile, SEMA3F knockdown decreased E-cadherin expression but increased the expression of N-cadherin and ß-Catenin, which indicated that SEMA3F could inhibit epithelial-mesenchymal transition (EMT). Mechanically, knockdown of SEMA3F inhibited GSK-3ß protein expression and promoted the expression of ß-Catenin and c-myc proteins. GSK-3ß is a key upstream suppressor of ß-Catenin and c-myc expression is an indicator of Wnt/ß-Catenin activity. Therefore, these results suggest that down-regulated SEMA3F may promote EMT, migration, invasion and metastasis of osteosarcoma via activating Wnt/ß-Catenin signaling. In conclusion, SEMA3F is downregulated and associated with prognosis of patients, indicating that SEMA3F may be a potential prognostic biomarker and therapeutic target for osteosarcoma.

Matrix stiffness promotes cartilage endplate chondrocyte calcification in disc degeneration via miR-20a targeting ANKH expression.

The mechanical environment is crucial for intervertebral disc degeneration (IDD). However, the mechanisms underlying the regulation of cartilage endplate (CEP) calcification by altered matrix stiffness remain unclear. In this study, we found that matrix stiffness of CEP was positively correlated with the degree of IDD, and stiff matrix, which mimicked the severe degeneration of CEP, promoted inorganic phosphate-induced calcification in CEP chondrocytes. Co-expression analysis of the miRNA and mRNA profiles showed that increasing stiffness resulted in up-regulation of miR-20a and down-regulation of decreased ankylosis protein homolog (ANKH) during inorganic phosphate-induced calcification in CEP chondrocytes. Through a dual luciferase reporter assay, we confirmed that miR-20a directly targets 3'-untranslated regions of ANKH. The inhibition of miR-20a attenuated the calcium deposition and calcification-related gene expression, whereas the overexpression of miR-20a enhanced calcification in CEP chondrocytes on stiff matrix. The rescue of ANKH expression restored the decreased pyrophosphate efflux and inhibited calcification. In clinical samples, the levels of ANKH expression were inversely associated with the degeneration degree of CEP. Thus, our findings demonstrate that the miR-20a/ANKH axis mediates the stiff matrix- promoted CEP calcification, suggesting that miR-20a and ANKH are potential targets in restraining the progression of IDD.

Partition and size distribution of heavy metals in the flue gas from municipal solid waste incinerators in Taiwan.

This study investigates the partition of heavy metals in both solid and gas phases in the flue gas from municipal solid waste (MSW) incinerators. Six MSW incinerators in Taiwan were examined and heavy metals in the flue gas at the inlets and outlets of air pollution control devices (APCDs) were analyzed. Heavy metals including Hg, Pb, Cd, Zn, Cu and Cr were sampled by USEPA Method 29 and further analyzed using inductively coupled plasma-mass spectroscopy (ICP-MS) and cold vapor atomic absorption spectrometry (CVAAS). Experimental results revealed that the removal efficiencies of the APCDs for the heavy metals Pb, Cd, Zn, Cu and Cr greatly exceeded 90%, but that of Hg did not. Two groups of heavy metals upstream of APCDs were observed. Pb, Cd, Zn, Cu and Cr were present mainly in the solid phase with a solid to gas ratio (S/G) of over 12.3. However, in most cases, mercury appeared mainly in the gas phase with an S/G ratio from 0.15 to 1.04, because it has a low boiling point. Additionally, treatment with the APCDs increased the S/G ratio of mercury because gaseous mercury could be removed by injecting powdered activated carbon (PAC) into the flue gas. Moreover, the distribution of particle sizes in the solid phase was bimodal. Finer particles (d(p)2.5 microm) contained more Cr and Hg.

Distinct reactivities on segmented selenium nanorods.

We demonstrate a new approach to synthesize several unique nanostructures by tuning the selective reactivities on individual symmetry-breaking segmented selenium nanorods (SBS-SeNRs). The segment-selective reactions from thiolated silane endowed the formation of float-like SBS-SeNR@SiO2 with a silica coating on the t-Se segment. Several other unique nanostructures were further synthesized by applying other selective reactions, such as Se chemical removal and nanogold deposition. Such a segmented nanomaterial of SBS-SeNRs acts as a new chemical template for preparing various segmented nanocomposites.

Preparation of sulfurized powdered activated carbon from waste tires using an innovative compositive impregnation process.

The objective of this study is to develop an innovative compositive impregnation process for preparing sulfurized powdered activated carbon (PAC) from waste tires. An experimental apparatus, including a pyrolysis and activation system and a sulfur (S) impregnation system, was designed and applied to produce sulfurized PAC with a high specific surface area. Experimental tests involved the pyrolysis, activation, and sulfurization of waste tires. Waste-tire-derived PAC (WPAC) was initially produced in the pyrolysis and activation system. Experimental results indicated that the Brunauer-Emmett-Teller (BET) surface area of WPAC increased, and the average pore radius of WPAC decreased, as water feed rate and activation time increased. In this study, a conventional direct impregnation process was used to prepare the sulfurized PAC by impregnating WPAC with sodium sulfide (Na2S) solution. Furthermore, an innovative compositive impregnation process was developed and then compared with the conventional direct impregnation process. Experimental results showed that the compositive impregnation process produced the sulfurized WPAC with high BET surface area and a high S content. A maximum BET surface area of 886 m2/g and the S content of 2.61% by mass were obtained at 900 degrees C and at the S feed ratio of 2160 mg Na2S/g C. However, the direct impregnation process led to a BET surface area of sulfurized WPAC that decreased significantly as the S content increased.

[Investigation of reproductive organs of male children and juvenile of the Meng and the Han nationality in Chifeng area].

OBJECTIVES: To investigate the development and the health of reproductive organs of male children and juvenile between the Meng and the Han nationality in the Meng nationality area. METHODS: Male juvenile(4-18 years old) of the Meng nationality (n = 2,315) and the Han nationality (n = 2,832) were divided into four age groups. Height, weight, length and perimeter of penis, volume of left and right testis and reproductive organs illness were examined. RESULTS: In 13-18 years group, the developmental speed of reproductive organs was faster in Mongolia male juvenile than that in the Han nationality (P < 0.02). After 13 years old, the developmental speed of reproductive organs of male living in town is faster than that in the country (P < 0.05). Illness of male reproductive organs was common such as hernia, varicocle etc. CONCLUSIONS: There was difference of developmental status and the prevalence rate of reproductive organs of male children and juvenile between the Meng and the Han nationality.

Utilization of stem cells in alginate for nucleus pulposus tissue engineering.

In a general view of anatomy, intervertebral disc is composed of three parts: annulus fibrosus (AF), nucleus pulposus (NP), and cartilage endplate (CEP). Recently, several types of stem cells were successfully isolated from these corresponding regions, but up to now, no research was performed about which kind of stem cells is the most efficient candidate for NP tissue engineering or for stem cell-based disc regeneration therapy. In this study, we compared the regenerative potentials of the above-mentioned three kinds of disc-derived stem cells with that of the classic bone marrow (BM)-mesenchymal stem cells (MSCs) in a rabbit disc degeneration model. By magnetic resonance imaging (MRI), X-ray, histology, etc. evaluations, we found that cartilage endplate-derived stem cells (CESCs) showed superior capacity compared with the annulus fibrosus-derived stem cells (AFSCs), nucleus pulposus-derived stem cells (NPSCs), and BM-MSCs (p<0.05); additionally, when comparing the CESC group with the normal control group, there existed no statistical difference in X-ray (p>0.05). Those results demonstrated that the CESC-seeded alginate construct performed the most powerful ability for NP regeneration, while AFSCs showed the most inferior potency, NPSCs and BM-MSCs had similar regenerative capacity and located in the middle. All in all, our study showed that CESCs might act as an efficient seed cell source for NP tissue engineering, which paved a new way for the biological solution of disc degeneration diseases.

Biomimetic ZnO plate twin-crystals periodical arrays.

We report a periodically patterned organization of hierarchical ZnO twin-crystals on a planar substrate in a biomimetic solution process. The deposition of the porous complex ZnO structure on specific sites of the substrate is achieved by introduction of the substrate surface modification and gelatin in a hydrothermal crystallization of ZnO.

Silver-coated gold nanoparticles as concentrating probes and matrices for surface-assisted laser desorption/ionization mass spectrometric analysis of aminoglycosides.

A novel method for the determination of aminoglycosides by surface-assisted laser desorption/ionization mass spectrometry (SALDI MS) with the aid of silver-coated gold nanoparticles (Au@AgNPs) has been developed. The Au@AgNPs with surface capped by anionic citrate were used as concentrating probes as well as matrices in SALDI MS. Adsorption of aminoglycosides onto the nanoparticles was mainly through electrostatic attraction. The aminoglycoside-adsorbed nanoparticles were directly characterized by SALDI MS after a simple washing. Using Au@AgNPs to preconcentrate the aminoglycosides from 500 microL buffer solution, the limits of detection (LODs) at signal-to-noise ratio of 3 were 3, 25, 15, 30, and 38 nM for paromomycin, kanamycin A, neomycin, gentamicin, and apramycin, respectively. This method was successfully applied to the determination of aminoglycosides in human plasma samples. The LODs of aminoglycosides in plasma samples were 9, 130, 81, and 180 nM for paromomycin, kanamycin A, neomycin, and gentamicin, respectively. Recoveries of aminoglycosides in plasma samples were about 80%.