A novel extracellular vesicles production system harnessing matrix homeostasis and macrophage reprogramming mitigates osteoarthritis.

Osteoarthritis (OA) is a degenerative disease that significantly impairs quality of life. There is a pressing need for innovative OA therapies. While small extracellular vesicles (sEVs) show promising therapeutic effects against OA, their limited yield restricts clinical translation. Here, we devised a novel production system for sEVs that enhances both their yield and therapeutic properties. By stimulating mesenchymal stem cells (MSCs) using electromagnetic field (EMF) combined with ultrasmall superparamagnetic iron oxide (USPIO) particles, we procured an augmented yield of EMF-USPIO-sEVs. These vesicles not only activate anabolic pathways but also inhibit catabolic activities, and crucially, they promote M2 macrophage polarization, aiding cartilage regeneration. In an OA mouse model triggered by anterior cruciate ligament transection surgery, EMF-USPIO-sEVs reduced OA severity, and augmented matrix synthesis. Moreover, they decelerated OA progression through the microRNA-99b/MFG-E8/NF-κB signaling axis. Consequently, EMF-USPIO-sEVs present a potential therapeutic option for OA, acting by modulating matrix homeostasis and macrophage polarization.

Nupr1-mediated vascular smooth muscle cell phenotype transformation involved in methamphetamine induces pulmonary hypertension.

AIMS: Nuclear protein 1 (Nupr1) is a multifunctional stress-induced protein involved in the regulation of tumorigenesis, apoptosis, and autophagy. However, its role in pulmonary hypertension (PH) after METH exposure remains unexplored. In this study, we aimed to investigate whether METH can induce PH and describe the role and mechanism of Nupr1 in the development of PH. METHODS AND RESULTS: Mice were made to induce pulmonary hypertension (PH) upon chronic intermittent treatment with METH. Their right ventricular systolic pressure (RVSP) was measured to assess pulmonary artery pressure. Pulmonary artery morphometry was determined by H&E staining and Masson staining. Nupr1 expression and function were detected in human lungs, mice lungs exposed to METH, and cultured pulmonary arterial smooth muscle cells (PASMCs) with METH treatment. Our results showed that chronic intermittent METH treatment successfully induced PH in mice. Nupr1 expression was increased in the cultured PASMCs, pulmonary arterial media from METH-exposed mice, and METH-ingested human specimens compared with control. Elevated Nupr1 expression promoted PASMC phenotype change from contractile to synthetic, which triggered pulmonary artery remodeling and resulted in PH formation. Mechanistically, Nupr1 mediated the opening of store-operated calcium entry (SOCE) by activating the expression of STIM1, thereby promoting Ca2+ influx and inducing phenotypic conversion of PASMCs. CONCLUSIONS: Nupr1 activation could promote Ca2+ influx through STIM1-mediated SOCE opening, which promoted METH-induced pulmonary artery remodeling and led to PH formation. These results suggested that Nupr1 played an important role in METH-induced PH and might be a potential target for METH-related PH therapy.

Electrophoretic deposition of magnesium oxide coating on micro-arc oxidized titanium for antibacterial activity and biocompatibility.

Titanium (Ti) dental implants face risks of early failure due to bacterial adhesion and biofilm formation. It is thus necessary to endow the implant surface with antibacterial ability. In this study, magnesium oxide (MgO) coatings were prepared on Ti by combining micro-arc oxidation (MAO) and electrophoretic deposition (EPD). The MgO nanoparticles homogeneously deposited on the microporous surface of MAO-treated Ti, yielding increasing coverage with the EPD time increased to 15 to 60 s. After co-culture with Porphyromonas gingivalis (P. gingivalis) for 24 h, 48 h, and 72 h, the coatings produced antibacterial rates of 4-53 %, 27-71 %, and 39-79 %, respectively, in a dose-dependent manner. Overall, EPD for 45 s offered satisfactory comprehensive performance, with an antibacterial rate 79 % at 72 h and a relative cell viability 85 % at 5 d. Electron and fluorescence microscopies revealed that, both the density of adherent bacterial adhesion on the surface and the proportion of viable bacteria decreased with the EPD time. The morphology of cells on the surface of each group was intact and there was no significant difference among the groups. These results show that, the MgO coating deposited on MAO-treated Ti by EPD had reasonably good in vitro antibacterial properties and cytocompatibility.

Cell response and bone ingrowth to 3D printed Ti6Al4V scaffolds with Mg-incorporating sol-gel Ta2O5 coating.

In recent years, additive manufacturing techniques have been used to fabricate 3D titanium (Ti)-based scaffolds for production of desirable complex shapes. However, insufficient osteointegration of porous Ti-based scaffolds can elicit long-term complications (e.g., aseptic loosening) and need further revision surgery. In this study, a magnesium (Mg)-incorporating tantalum (Ta) coating was deposited on a 3D Ti6Al4V scaffold using a sol-gel method for enhancing its osteogenic properties. To evaluate the biofunction of this surface, bone mesenchymal stem cells and rabbit femoral condyle were used to assess the cell response and bone ingrowth, respectively. Ta2O5 coatings and Mg-incorporating Ta2O5 coatings were both homogeneously deposited on porous scaffolds. In vitro studies revealed that both coatings exhibit enhanced cell proliferation, ALP activity, osteogenic gene expression and mineralization compared with the uncoated Ti6Al4V scaffold. Especially for Mg-incorporating Ta2O5 coatings, great improvements were observed. In vivo studies, including radiographic examination, fluorochrome labeling and histological evaluation also followed similar trends. Also, bone ingrowth to scaffolds with Mg-incorporating Ta2O5 coatings exhibited the most significant increase compared with uncoated and Ta2O5 coated scaffolds. All the above results indicate that Mg-doped Ta2O5 coatings are an effective tool for facilitating osteointegration of conventional porous Ti6Al4V scaffolds.

[Preparation and properties of a new artificial bone composite material].

Objective: To study the preparation and properties of the hyaluronic acid (HA)/α-calcium sulfate hemihydrate (α-CSH)/ß-tricalcium phosphate (ß-TCP) material (hereinafter referred to as composite material). Methods: Firstly, the α-CSH was prepared from calcium sulfate dihydrate by hydrothermal method, and the ß-TCP was prepared by wet reaction of soluble calcium salt and phosphate. Secondly, the α-CSH and ß-TCP were mixed in different proportions (10∶0, 9∶1, 8∶2, 7∶3, 5∶5, and 3∶7), and then mixed with HA solutions with concentrations of 0.1%, 0.25%, 0.5%, 1.0%, and 2.0%, respectively, at a liquid-solid ratio of 0.30 and 0.35 respectively to prepare HA/α-CSH/ ß-TCP composite material. The α-CSH/ß-TCP composite material prepared with α-CSH, ß-TCP, and deionized water was used as the control. The composite material was analyzed by scanning electron microscope, X-ray diffraction analysis, initial/final setting time, degradation, compressive strength, dispersion, injectability, and cytotoxicity. Results: The HA/α-CSH/ß-TCP composite material was prepared successfully. The composite material has rough surface, densely packed irregular block particles and strip particles, and microporous structures, with the pore size mainly between 5 and 15 µm. When the content of ß-TCP increased, the initial/final setting time of composite material increased, the degradation rate decreased, and the compressive strength showed a trend of first increasing and then weakening; there were significant differences between the composite materials with different α-CSH/ß-TCP proportion ( P<0.05). Adding HA improved the injectable property of the composite material, and it showed an increasing trend with the increase of concentration ( P<0.05), but it has no obvious effect on the setting time of composite material ( P>0.05). The cytotoxicity level of HA/α-CSH/ß-TCP composite material ranged from 0 to 1, without cytotoxicity. Conclusion: The HA/α-CSH/ß-TCP composite materials have good biocompatibility. Theoretically, it can meet the clinical needs of bone defect repairing, and may be a new artificial bone material with potential clinical application prospect.

Biomechanical comparison of the new cross-locking intramedullary nail with tension band wiring for transverse olecranon fractures.

BACKGROUND: In the treatment of transverse olecranon fractures, complicated tension band wiring (TBW) has high rates of re-operations. Besides, plate fixation (PF) and TBW both have large surgical incisions and soft-tissue irritation. Therefore, the new cross-locking intramedullary nail (CIN) with easy handling and minimally invasive features is significantly advantageous. The goal of this study was to biomechanically compare CIN with TBW for fixing transverse olecranon fracture. METHODS: The transverse olecranon fracture models were created with 15 fresh-frozen cadaveric ulnae which were randomly divided into 3 groups: one group for TBW fixation, another for CIN fixation with 1 conical locking screw (CIN-1), and the last for CIN fixation with 3 conical locking screws (CIN-3). The stiffness, cyclic stability, and failure strength of the fixed fracture models were compared after the corresponding experimental tests. RESULTS: The failure strength of TBW, CIN-1 and CIN-3 were (313.38±27.68) N, (528.56±53.58) N and (871.04±94.95) N. There was a significant difference between them. However, as for dynamic stability and stiffness, CIN-3 was higher and TBW was lower, with no significant differences between the groups. CONCLUSION: The biomechanical properties of CIN were superior to those of TBW, and CIN was more stable and solid for fixing transverse olecranon fracture, of which CIN-3 was the strongest.

Demographic and health predictors of telomere length during adolescence.

Telomere length (TL) is proposed to play a mechanistic role in how the exposome affects health outcomes. Little is known about TL during adolescence, a developmental period during which precursors of adult-onset health problems often emerge. We examined health and demographic sources of variation in TL in 899 youth aged 11-17. Demographic and health information included age, sex, race, household income, caregiver age and marital status, youth tobacco exposure, body mass index, pubertal status, health problems, medication use, and season of data collection. Genomic DNA was extracted from saliva, and T/S ratios were computed following qPCR. Age, race, season of data collection, and household income were associated with the telomere to single copy (T/S) ratio. We found that T/S ratios were larger at younger ages, among Black youth, for saliva collected during autumn and winter, and among households with higher income. Analyses stratified by race revealed that the association between age and T/S ratio was present for Black youth, that season of collection was present across races, but that family demographic associations with T/S ratio varied by race. The results provide information for future telomere research and highlight adolescence as a potentially important developmental phase for racial disparities in telomere shortening and health.

Micro/nano-topography promotes osteogenic differentiation of bone marrow stem cells by regulating periostin expression.

Micro/nano-topography (MNT) is an important factor affecting cell response. Earlier studies using titania (TiO2) nanotube as a model of MNT found that they mediated the differentiation of BMSCs into osteoblasts, but the mechanisms are not fully understood. Surprisingly, Periostin (Postn), a secreted protein involved in extracellular matrix (ECM) construction and promoting osteogenic differentiation of bone marrow stem cells (BMSCs), was previously observed to significantly up-regulated on TiO2 nanotube. We proposed that Postn may act as a MNT signal transduction role. In this study, we investigated the effect of MNT on Postn, and the influence of Postn on osteogenic differentiation-related genes through focal adhesion and downstream signals. It was found that, titanium (Ti) plates carrying TiO2 nanotubes with diameters of ∼100 nm (TNT-100) significantly up-regulated the expression of Postn compared with flat Ti. Furthermore, Postn activated the downstream focal adhesion kinase (FAK) signal pathway and ß-catenin into the nucleus by interacting with integrin αV. Surprisingly, TNT-100 up-regulated the transcription level of Wnt3a, which was independent of the up-regulation of Postn. This new Postn signaling pathway may provide more insights into the signal transduction mechanism of MNT and development of biomaterials with improved osteogenic properties.

Improved cell seeding efficiency and cell distribution in porous hydroxyapatite scaffolds by semi-dynamic method.

Tissue engineering is a promising technique for the repair of bone defects. An efficient and homogeneous distribution of cell seeding into scaffold is a crucial but challenging step in the technique. Murine bone marrow mesenchymal stem cells were seeded into porous hydroxyapatite scaffolds of two morphologies by three methods: static seeding, semi-dynamic seeding, or dynamic perfusion seeding. Seeding efficiency, survival, distribution, and proliferation were quantitatively evaluated. To investigate the performance of the three seeding methods for larger/thicker scaffolds as well as batch seeding of numerous scaffolds, three scaffolds were stacked to form assemblies, and seeding efficiencies and cell distribution were analyzed. The semi-dynamic seeding and static seeding methods produced significantly higher seeding efficiencies, vitalities, and proliferation than did the dynamic perfusion seeding. On the other hand, the semi-dynamic seeding and dynamic perfusion seeding methods resulted in more homogeneous cell distribution than did the static seeding. For stacked scaffold assemblies, the semi-dynamic seeding method also created superior seeding efficiency and longitudinal cell distribution homogeneity. The semi-dynamic seeding method combines the high seeding efficiency of static seeding and satisfactory distribution homogeneity of dynamic seeding while circumventing their disadvantages. It may contribute to improved outcomes of bone tissue engineering.

Effects of hypoxia on Achilles tendon repair using adipose tissue-derived mesenchymal stem cells seeded small intestinal submucosa.

BACKGROUND: The study was performed to evaluate the feasibility of utilizing small intestinal submucosa (SIS) scaffolds seeded with adipose-derived mesenchymal stem cells (ADMSCs) for engineered tendon repairing rat Achilles tendon defects and to compare the effects of preconditioning treatments (hypoxic vs. normoxic) on the tendon healing. METHODS: Fifty SD rats were randomized into five groups. Group A received sham operation (blank control). In other groups, the Achilles tendon was resected and filled with the original tendon (Group B, autograft), cell-free SIS (Group C), or SIS seeded with ADMSCs preconditioned under normoxic conditions (Group D) or hypoxic conditions (Group E). Samples were collected 4 weeks after operation and analyzed by histology, immunohistochemistry, and tensile testing. RESULTS: Histologically, compared with Groups C and D, Group E showed a significant improvement in extracellular matrix production and a higher compactness of collagen fibers. Group E also exhibited a significantly higher peak tensile load than Groups D and C. Additionally, Group D had a significantly higher peak load than Group C. Immunohistochemically, Group E exhibited a significantly higher percentage of MKX + cells than Group D. The proportion of ADMSCs simultaneously positive for both MKX and CM-Dil observed from Group E was also greater than that in Group D. CONCLUSIONS: In this animal model, the engineered tendon grafts created by seeding ADMSCs on SIS were superior to cell-free SIS. The hypoxic precondition further improved the expression of tendon-related genes in the seeded cells and increased the rupture load after grafting in the Achilles tendon defects.

Environmentally favorable magnesium phosphate anti-corrosive coating on carbon steel and protective mechanisms.

Polymer coatings are commonly used to protect carbon steels from corrosion but they are susceptible to weathering and many of them have environmental concerns. Therefore, we studied the possibility of an environmentally favorable inorganic magnesium phosphate cement (MPC) coating for protecting mild steel. A formulation suitable for coating steel was developed by compositional modification [i.e., incremental replacement of dead-burned magnesia (MgO) with magnesium hydroxide (Mg(OH)2)] to a road-repair MPC. This modification yielded an acceptable working time and prevented pore formation at the coating-steel interface. Corrosion monitoring by linear polarization and electrochemical impedance spectroscopy for 14 days found that, the MPC coating substantially increased the linear polarization resistance (Rp) [e.g., day 1: (8.2 ± 1.7) × 103 (nadir value) vs. 495 ± 55 Ω cm-2] and charge transfer resistance (Rct) (e.g., day 1: 9.3 × 103 vs. 3.8 × 102 Ω cm-2). The coated steel underwent neutral sodium chloride (NaCl) salt spray for 2400 h without visible rusting. Immersion for 24 h in liquids simulating the pore fluid indicated that, passivation by the excess MgO in the coating was a major contributor to its anti-corrosive property. Tafel polarization in the liquids found that, corrosion current density (Icorr) followed the rank: 3.5% NaCl solution (6.0 µA cm-2) > 3.5% NaCl solution containing MgO (3.6 µA cm-2) > 3.5% NaCl solution containing fragmented MPC (1.7 µA cm-2), suggesting that a physical barrier effect and dissolved phosphate ions improved its protection. This study shows that, MPC coating is a promising durable and environmentally favorable anti-corrosive material for protecting steel structures in some applications.

Treatment of Retroperitoneal Cavernous Lymphangioma: A Case Report.

A 32-year-old man who complained of recurrent nauseat and vomiting was admitted to our hospital. The contrast-enhanced computed tomography revealed a cystic mass located behind the duodenum which was suggestive of lymphangioma. Laparoscopic resection of the retroperitoneal mass was successfully performed. The postoperatively pathological examination confirmed the diagnosis of cavernous lymphangioma. Ultrasound and enhanced CT can be used for making a preoperative diagnosis. Once symptoms of the disease develop, complete surgical resection should be performed.

3D Bioprinting of shear-thinning hybrid bioinks with excellent bioactivity derived from gellan/alginate and thixotropic magnesium phosphate-based gels.

3D Bioprinting is expected to become a strong tool for regenerative medicine, but satisfactory bioinks for the printing of constructs containing living cells are lacking due to the rigorous requirement of high printability and biocompatibility, which are often contradictory. Here, we have reported the development of a novel hybrid bioink by combining rigid gellan gum (GG), flexible sodium alginate (SA), and a bioactive substance thixotropic magnesium phosphate-based gel (TMP-BG). The ratio of these components was first optimized to obtain satisfactory gelating, mechanical, rheological, and printing properties. The formulated hybrid GG-SA/TMP-BG bioink had a good printability due to the shear-thinning and its multiple cross-linking by Mg2+ and Ca2+. The tunable mechanical performance of the hybrid bioink could simulate various extracellular matrices of the different tissues and support integrity of 3D printing constructs. Moreover, the hybrid bioink induced apatite deposition during immersion in simulated body fluids, and also promoted cell proliferation in vitro. MG-63 osteosarcoma cells were dispersed in the bioink and printed into 3D constructs. The cells exhibited good cell survival due to the shear-thinning property of the bioink and the ion concentration used for cross-linking. The proliferation rate of the cells also significantly exceeded those in non-printed samples. Confocal microscopy revealed a homogeneous distribution of cells in the printed constructs, and survival for more than 7 d. In vivo animal experiments showed that the hybrid bioink without cells could induce osteochondral repair. Therefore, this hybrid bioink has good printability, biocompatibility, mechanical support, and bioactivity, which is expected to have promising applications in 3D bioprinting.

AMOT130/YAP pathway in topography-induced BMSC osteoblastic differentiation.

Micro/nano-topography (MNT) is an important variable affecting osseointegration of bone biomaterials, but the underlying mechanisms are not fully understood. We probed the role of a AMOT130/YAP pathway in osteoblastic differentiation of bone marrow mesenchymal stems cultured on titanium (Ti) carrying MNTs. Ti surfaces with two well-defined MNTs (TiO2 nanotubes of different diameters and wall thicknesses) were prepared by anodization. Rat BMSCs were cultured on flat Ti and Ti surfaces carrying MNTs, and cell behaviors (i.e., morphology, F-actin development, osteoblastic differentiation, YAP localization) were studied. Ti surfaces carrying MNTs increased F-actin formation, osteoblastic gene expression, and protein AMOT130 production in BMSCs (all vs. flat Ti), and the surface carrying larger nantubes was more effective, confirming osteoblastic differentiation induced by MNTs. Elevation of the AMOT130 level (by inhibiting its degradation) increased the osteoblastic gene expression, F-actin formation, and nuclear localization of YAP. These show that, AMOT130/YAP is an important pathway mediating the translation of MNT signals to BMSC osteoblastic commitment, likely via the cascade: AMOT130 promotion of F-actin formation, increased YAP nuclear import, and activation of osteoblastic gene expression.

Experimental and simulation studies of strontium/fluoride-codoped hydroxyapatite nanoparticles with osteogenic and antibacterial activities.

Multiple ions codoping may effectively modulate physicochemical and biological properties of hydroxyapatite (HA) for diverse biomedical applications. This study synthesized strontium (Sr)-, fluorine (F)- doped, and Sr/F-codoped HA nanoparticles by a hydrothermal method, and investigated the effect of ion doping on characteristics of HA, including crystallinity, crystal size, lattice parameters, and substitution sites by experiments and simulation with density functional theory (DFT) methods. It was found that, Sr doping increased the lattice parameters of HA whereas F doping decreased these parameters. Additionally, F doping enhanced the structural stability of the Sr-doped HA. F doping created excellent antibacterial properties to effectively inhibit growth of Streptococcus mutans. An appropriate Sr doping level endowed HA with optimum osteogenic ability to promote osteoblastic differentiation of bone marrow stem cells. These suggest that, Sr/F codoping is an effective approach to synthesizing HA-based materials with both antibacterial and osteogenic properties. More broadly, HA nanomaterials with specific characteristics may be designed for meeting diverse requirements from biomedical applications.

Leptin promotes fatty acid oxidation and OXPHOS via the c-Myc/PGC-1 pathway in cancer cells.

Alteration in cellular energy metabolism plays a critical role in the development and progression of cancer. Leptin is a hormone secreted by adipose tissue. Recent reports have shown that leptin can induce cancer cell proliferation and regulate cell energy metabolism, but the regulatory mechanism is still unclear. Here, we showed that leptin could promote cell proliferation and maintain high adenosine triphosphate levels in HCT116 and MCF-7 cells. The expression levels of carnitine palmitoyl transferase 1A (CPT1A), pyruvate dehydrogenase, succinate dehydrogenase subunit A and mitochondrial respiratory chain-associated proteins NADH dehydrogenase 1 (ND1), NADH:ubiquinone oxidoreductase subunit B8, and mitochondrial transcription factor A (TFAM) were distinctly increased in leptin-treated HCT116 and MCF-7 cells, while fatty acid synthase and lactate dehydrogenase expression were downregulated. Simultaneously, we found that c-Myc and peroxisome proliferator-activated receptor gamma co-activator 1 (PGC-1) protein expression levels were significantly increased. These results indicated that leptin boosted fatty acid ß-oxidation and the tricarboxylic acid cycle, enhanced oxidative phosphorylation (OXPHOS) activity, and inhibited fatty acid synthesis and glycolysis in tumor cells. Gene transfection experiments revealed that leptin could induce the expression of c-Myc. Moreover, the expressions of PGC-1, CPT1A, and TFAM proteins were downregulated in HCT116 cells with low expression of c-Myc, and the expression levels of these proteins were increased in HCT116 cells overexpressing c-Myc. These findings suggest that leptin plays an important role in the regulation of energy metabolism in tumor cells. It may regulate fatty acid oxidation and OXPHOS of tumor cells by regulating the c-Myc/PGC-1 pathway. Targeting metabolic pathways for cancer treatment has been investigated as potential preventive or therapeutic methods. This study has important implications for the clinical therapy of tumor cell metabolism through hormone regulation.

Cation Channel Transient Receptor Potential Vanilloid 4 Mediates Topography-Induced Osteoblastic Differentiation of Bone Marrow Stem Cells.

Micro/nanotopographies (MNTs) have been reported to enhance the osseointegration of biomaterials and modulate cell functions, but the underlying mechanisms are incompletely understood. We hypothesized that transient receptor potential vanilloid 4 (TRPV4) may mediate the topographically induced osteoblastic differentiation of bone marrow stem cells (BMSCs) by regulating the NFATc1 and Wnt/ß-catenin signaling. To test this hypothesis, murine BMSCs were cultured on polished titanium (Ti) discs (PT) and Ti discs carrying titania nanotubes (i.e., MNTs) with diameters of ∼30 and ∼100 nm (termed TNT-30 and TNT-100, respectively). It was found that the MNTs (in particular TNT-100) promoted the expression and activation of TRPV4. Inhibition of TRPV4 in BMSCs cultured on TNT-100 reduced the expression of osteoblastic genes and the gene expression and protein levels of NFATc1 and Wnt3a/ß-catenin and also decreased nuclear translocation of NFATc1 and ß-catenin (all vs uninhibited BMSCs). Conversely, activation of TRPV4 in BMSCs cultured on PT increased the expression of the osteoblastic gene and the gene expression and protein level of NFATc1 and Wnt3a/ß-catenin and also enhanced the nuclear translocation of NFATc1 and ß-catenin (all vs unactivated BMSCs). These differences suggest that the MNTs promoted TRPV4 expression and activation to enhance intracellular Ca2+, which further increased the nuclear translocation of NFATc1 and stimulated the Wnt/ß-catenin signaling, thus leading to upregulated expression of osteoblastic genes. These results indicate TRPV4 to be a mediator in MNT-induced osteoblastic differentiation of BMSCs.

Lactic acid induces lactate transport and glycolysis/OXPHOS interconversion in glioblastoma.

The Warburg effect is a dominant phenotype of most tumor cells. Recent reports have shown that the Warburg effect can be reprogrammed by the tumor microenvironment. Lactic acidosis and glucose deprivation are the common adverse microenvironments in solid tumor. The metabolic reprogramming induced by lactic acid and glucose deprivation remains to be elucidated in glioblastoma. Here, we show that, under glucose deprivation, lactic acid can preserve high ATP levels and resist cell death in U251 cells. At the same time, we find that MCT1 and MCT4 are significantly highly expressed. The metabolic regulation factor HIF-1α decreased and C-MYC increased. Nuclear respiratory factor 1 (NRF1) and oxidative phosphorylation (OXPHOS)-related proteins (NDUFB8, ND1) are all distinctly increased. Therefore, lactic acid can induce lactate transport and convert the dominant Warburg effect to OXPHOS. Through bioinformatics analysis, the high expression of HIF-1α, MCT1 or MCT4 indicate a poor prognosis in glioblastoma. In addition, in glioblastoma tissue, HIF-1α, MCT4 and LDH are highly expressed in the interior region, and their expression is decreased in the lateral region. MCT1 can not be detected in the interior region and is highly expressed in the lateral region. Hence, different regions of glioblastoma have diverse energy metabolic pathways. Glycolysis occurs mainly in the interior region and OXPHOS in the lateral region. In general, lactic acid can induce regional energy metabolic reprogramming and assist tumor cells to adapt and resist adverse microenvironments. This study provides new ideas for furthering understanding of the metabolic features of glioblastoma. It may promote the development of new therapeutic strategies in GBM.

Dual-inflammatory cytokines on TiO2 nanotube-coated surfaces used for regulating macrophage polarization in bone implants.

Excessive immune responses following the use of implantable, biomaterial-based medical devices represent a substantial challenge for treatment efficacy and patient well-being. Specifically, after implantation, pro-inflammatory M1 macrophages are activated by cytokines such as interferon-γ (IFN-γ) followed by anti-inflammatory M2 macrophages polarized by cytokines including interleukin-4 (IL-4), leading to healing and long-term stability of implants. Here, we report the loading of an immunomodulatory cytokine,IL-4, into TiO2 nanotubes (TNTs) followed by hydrogel coating on the TNTs for subsequent release of IL-4. Finally, IFN-γ was added onto the gel layer to effect rapid release. The release rates of both cytokines from the samples were monitored using an immersion test in phosphate-buffered solution. The cytocompatibility of the sample was evaluated using cultures of osteoblasts and macrophages. Macrophage phenotype switching in vitro was examined via cytokine secretion and gene expression analyses. In vitro testing showed that the sample could stimulate macrophage polarization from the M1 to M2 phenotype at the desired period owing to temporal release of IFN-γ and IL-4. Another biomaterial containing only IL-4 in TNTs was also able to modulate the transformation of M1 to M2 although with weaker effect than that containing IFN-γ and IL-4. The biomaterial may be useful as an osteoimplant in vivo owing to the inflammation caused by a wound or implantation. This study provided biomaterials capable of facilitating smooth M1 to M2 macrophages switching, which might be helpful to research immune responses of tissues to implants and will likely contribute to the development of bone substitute materials. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1878-1886, 2018.

Macrophage phenotype switch by sequential action of immunomodulatory cytokines from hydrogel layers on titania nanotubes.

Inflammatory response occurring between tissues and implants after implantation has attracted increasing attention because it can cause local tissue necrosis and even implant failure. Macrophages play a key role in all stages of inflammation. Pro-inflammatory (M1) and anti-inflammatory (M2) macrophages comprise two main phenotypes and the switch from M1 to M2 at specific time points is important for wound healing and tissue regeneration. Therefore, we hypothesized that biomaterial systems capable of facilitating macrophage phenotype switching should attenuate inflammation and enhance healing. To this end, a system of double hydrogel layers on titania nanotubes (TNT) was prepared as reservoir to modulate the release of interleukin-4 (IL-4) and interferon-γ (IFN-γ). In this system, IL-4, an anti-inflammatory cytokine, was loaded in TNT and IFN-γ, a pro-inflammatory cytokine, was located between two hydrogel layers of chitosan/ß-glycerophosphate disodium and carboxymethyl chitosan/genipin. IFN-γ released rapidly in 3 days, whereas IL-4 exhibited a sustained release profile. In culture with mesenchymal stem cells and macrophages, this system displayed good cytocompatibility and significantly promoted cell proliferation. Macrophage phenotype switch was determined by ELISA, FACS and PCR. The results manifested that IFN-γ released from the system stimulated switching of macrophages to M1 in 3 days, whereas sustained release of IL-4 polarized macrophages to M2 after 4 days. This system can modulate macrophage phenotype switching from M1 to M2 by sequential action of the two cytokines, and might be used to research immune response between tissues and implants. The present study also provided a novel strategy for designing functional biomaterials.