Detection of lineage-reprogramming efficiency of tumor cells in a 3D-printed liver-on-a-chip model.

Background: The liver metastasis accompanied with the loss of liver function is one of the most common complications in patients with triple-negative breast cancers (TNBC). Lineage reprogramming, as a technique direct inducing the functional cell types from one lineage to another lineage without passing through an intermediate pluripotent stage, is promising in changing cell fates and overcoming the limitations of primary cells. However, most reprogramming techniques are derived from human fibroblasts, and whether cancer cells can be reversed into hepatocytes remains elusive. Methods: Herein, we simplify preparation of reprogramming reagents by expressing six transcriptional factors (HNF4A, FOXA2, FOXA3, ATF5, PROX1, and HNF1) from two lentiviral vectors, each expressing three factors. Then the virus was transduced into MDA-MB-231 cells to generated human induced hepatocyte-like cells (hiHeps) and single-cell sequencing was used to analyze the fate for the cells after reprogramming. Furthermore, we constructed a Liver-on-a-chip (LOC) model by bioprinting the Gelatin Methacryloyl hydrogel loaded with hepatocyte extracellular vesicles (GelMA-EV) bioink onto the microfluidic chip to assess the metastasis behavior of the reprogrammed TNBC cells under the 3D liver microenvironment in vitro. Results: The combination of the genes HNF4A, FOXA2, FOXA3, ATF5, PROX1 and HNF1A could reprogram MDA-MB-231 tumor cells into human-induced hepatocytes (hiHeps), limiting metastasis of these cells. Single-cell sequencing analysis showed that the oncogenes were significantly inhibited while the liver-specific genes were activated after lineage reprogramming. Finally, the constructed LOC model showed that the hepatic phenotypes of the reprogrammed cells could be observed, and the metastasis of embedded cancer cells could be inhibited under the liver microenvironment. Conclusion: Our findings demonstrate that reprogramming could be a promising method to produce hepatocytes and treat TNBC liver metastasis. And the LOC model could intimate the 3D liver microenvironment and assess the behavior of the reprogrammed TNBC cells.

Genome-Wide Analysis of ZAT Gene Family in Osmanthus fragrans and the Function Exploration of OfZAT35 in Cold Stress.

Osmanthus fragrans is a popular ornamental and odorant plant with high commercial value, but its cultivation and exploitation are limited by low temperature. The ZAT (zinc finger of Arabidopsis thaliana) genes as a subclass of the C2H2-type zinc finger proteins (C2H2-ZFP) family play essential roles in various abiotic stresses. However, their roles in cold stress response in O. fragrans remain unclear. This study identified 38 OfZATs, which could be divided into 5 subgroups based on the phylogenetic tree, with OfZATs in the same subgroup harboring similar gene structures and motif patterns. In addition, 49 segmental and 5 tandem duplication events were detected among OfZAT genes, while some OfZAT genes exhibited specific expression patterns in different tissues. Furthermore, two OfZATs were induced in salt stress and eight OfZATs responded to cold stress. Interestingly, OfZAT35 showed a continuously increasing expression trend under cold stress, while its protein showed nucleus localization with no transcriptional activation activity. Transiently transformed tobacco overexpressing OfZAT35 exhibited a significantly higher relative electrolyte leakage (REL) level and increased activities of superoxide dismutase (SOD), peroxidase (POD), and Ascorbate peroxidase (APX), while there was significantly decreased activity of catalase (CAT). Moreover, CAT, DREB3, and LEA5, which are associated with cold stress, were dramatically decreased after cold treatment in transiently transformed tobacco, suggesting that overexpression of OfZAT35 negatively regulated cold stress. This study provides a basis for exploring the roles of ZAT genes and contributes to uncovering the mechanism of ZAT-mediated cold stress response in O. fragrans.

Knockdown of SIRT3 perturbs protective effects of irisin against bone loss in diabetes and periodontitis.

A well-recognized risk factor for periodontitis, diabetes mellitus (DM) aggravates periodontal disease with increasing alveolar bone loss. As a novel myokine, irisin is closely linked with bone metabolism. Nonetheless, the effects of irisin on periodontitis under diabetic conditions and the underlying mechanisms remain poorly understood. Here, we showed that local irisin treatment ameliorates alveolar bone loss and oxidative stress, increases SIRT3 expression within periodontal tissues of our experimentally-induced diabetes and periodontitis (DP) rat models. By culturing the periodontal ligament cells (PDLCs) in vitro, we found that irisin could partially rescue inhibited cell viability, mitigate accumulated intracellular oxidative stress, ameliorate mitochondrial dysfunctions, and restore disturbed osteogenic and osteoclastogenic capacities of PDLCs when exposed to high glucose and pro-inflammatory stimulation. Furthermore, lentivirus-mediated SIRT3 knockdown was employed to unravel the underlying mechanism by which SIRT3 mediated irisin's beneficial effects on PDLCs. Meanwhile, in SIRT3-deficient mice, irisin treatment did not protect against alveolar bone destruction and oxidative stress accumulation in DP models, which underlined the crucial role of SIRT3 in mediating the positive effects of irisin on DP. Our findings, for the first time, revealed that irisin attenuates alveolar bone loss and oxidative stress via activation of the SIRT3 signaling cascade, and highlighted its therapeutic potential for the treatment of DP.

Silk fibers assisted long-term 3D culture of human primary urinary stem cells via inhibition of senescence-associated genes: Potential use in the assessment of chronic mitochondrial toxicity.

Despite being widely applied in drug development, existing in vitro 2D cell-based models are not suitable to assess chronic mitochondrial toxicity. A novel in vitro assay system mimicking in vivo microenvironment for this purpose is urgently needed. The goal of this study is to establish a 3D cell platform as a reliable, sensitive, cost-efficient, and high-throughput assay to predict drug-induced mitochondrial toxicity. We evaluated a long-term culture of human primary urine-derived stem cells (USC) seeded in 3D silk fiber matrix (3D USC-SFM) and further tested chronic mitochondrial toxicity induced by Zalcitabine (ddC, a nucleoside reverse transcriptase inhibitor) as a test drug, compared to USC grown in spheroids. The numbers of USC remain steady in 3D spheroids for 4 weeks and 3D SFM for 6 weeks. However, the majority (95%) of USC survived in 3D SFM, while cell numbers significantly declined in 3D spheroids at 6 weeks. Highly porous SFM provides large-scale numbers of cells by increasing the yield of USC 125-fold/well, which enables the carrying of sufficient cells for multiple experiments with less labor and lower cost, compared to 3D spheroids. The levels of mtDNA content and mitochondrial superoxide dismutase2 [SOD2] as an oxidative stress biomarker and cell senescence genes (RB and P16, p21) of USC were all stably retained in 3D USC-SFM, while those were significantly increased in spheroids. mtDNA content and mitochondrial mass in both 3D culture models significantly decreased six weeks after treatment of ddC (0.2, 2, and 10 µM), compared to 0.1% DMSO control. Levels of complexes I, II, and III significantly decreased in 3D SFM-USC treated with ddC, compared to only complex I level which declined in spheroids. A dose- and time-dependent chronic MtT displayed in the 3D USC-SFM model, but not in spheroids. Thus, a long-term 3D culture model of human primary USC provides a cost-effective and sensitive approach potential for the assessment of drug-induced chronic mitochondrial toxicity.

3D Spheroids of Human Primary Urine-Derived Stem Cells in the Assessment of Drug-Induced Mitochondrial Toxicity.

Mitochondrial toxicity (Mito-Tox) risk has increased due to the administration of several classes of drugs, particularly some life-long antiretroviral drugs for HIV+ individuals. However, no suitable in vitro assays are available to test long-term Mito-Tox (≥4 weeks). The goal of this study is to develop a 3D spheroid system of human primary urine-derived stem cells (USC) for the prediction of drug-induced delayed Mito-Tox. The cytotoxicity and Mito-Tox were assessed in 3D USC spheroids 4 weeks after treatment with antiretroviral drugs: zalcitabine (ddC; 0.1, 1 and 10 µM), tenofovir (TFV; 3, 30 and 300 µM) or Raltegravir (RAL; 2, 20 and 200 µM). Rotenone (RTNN, 10 µM) and 0.1% DMSO served as positive and negative controls. Despite only mild cytotoxicity, ddC significantly inhibited the expression of oxidative phosphorylation enzyme Complexes I, III, and IV; and RAL transiently reduced the level of Complex IV. A significant increase in caspase 3 and ROS/RNS level but a decrease in total ATP were observed in USC treated with ddC, TFV, RAL, and RTNN. Levels of mtDNA content and mitochondrial mass were decreased in ddC but minimally or not in TFV- and RAL-treated spheroids. Thus, 3D USC spheroid using antiretroviral drugs as a model offers an alternative platform to assess drug-induced late Mito-Tox.

Insights into the trihelix transcription factor responses to salt and other stresses in Osmanthus fragrans.

BACKGROUND: Osmanthus fragrans is an evergreen plant with high ornamental and economic values. However, they are easily injured by salt stress, which severely limits their use in high salinity areas. The trihelix transcription factor (TF) family, as one of the earliest discovered TF families in plants, plays an essential part in responses to different abiotic stresses, and it has potential functions in improving the salt-tolerance capability of O. fragrans. RESULTS: In this study, 56 trihelix genes (OfGTs) were first identified in O. fragrans and then divided into five subfamilies in accordance with a phylogenetic tree analysis. The OfGTs were found to be located randomly on the 20 O. fragrans chromosomes, and an analysis of gene replication events indicated that the OfGT gene family underwent strong purification selection during the evolutionary process. The analysis of conserved motifs and gene structures implied that the OfGT members in the same subfamily have similar conserved motifs and gene structures. A promoter cis-elements analysis showed that all the OfGT genes contained multiple abiotic and hormonal stress-related cis-elements. The RNA-seq data suggested that the OfGTs have specific expression patterns in different tissues, and some were induced by salt stress. The qRT-PCR analysis of 12 selected OfGTs confirmed that OfGT1/3/21/33/42/45/46/52 were induced, with OfGT3/42/46 being the most highly expressed. In addition, OfGT42/OfGT46 had a co-expression pattern under salt-stress conditions. OfGT3/42/46 were mainly localized in the nuclei and exhibited no transcriptional activities based on the analysis of the subcellular localization and transcriptional activity assay. Furthermore, the expression levels of most of the selected OfGTs were induced by multiple abiotic and hormonal stresses, and the expression patterns of some OfGTs were also highly correlated with gibberellic acid and methyl jasmonate levels. Remarkably, the transient transformation results showed lower MDA content and increased expression of ROS-related genes NbAPX in transgenic plants, which implying OfGT3/42/46 may improve the salt tolerance of tobacco. CONCLUSIONS: The results implied that the OfGT genes were related to abiotic and hormonal stress responses in O. fragrans, and that the OfGT3/42/46 genes in particular might play crucial roles in responses to salt stress. This study made a comprehensive summary of the OfGT gene family, including functions and co-expression patterns in response to salt and other stresses, as well as an evolutionary perspective. Consequently, it lays a foundation for further functional characterizations of these genes.

3-D Human Renal Tubular Organoids Generated from Urine-Derived Stem Cells for Nephrotoxicity Screening.

The development of human cell-based systems to replace the use of rodents or the two-dimensional culture of cells for studying nephrotoxicity is urgently needed. Human urine-derived stem cells were differentiated into renal tubular epithelial cells in three-dimensional (3-D) culture after being induced by a kidney extracellular matrix. Levels of CYP2E1 and KIM-1 in 3-D organoids were significantly increased in response to acetone and cisplatin. This 3-D culture system provides an alternative tool for nephrotoxicity screening and research.

Short versus standard implants for single-crown restorations in the posterior region: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Whether implant-supported crowns on short or standard implants have similar clinical outcomes in the posterior alveolar bone is unclear. PURPOSE: The purpose of this systematic review and meta-analysis was to compare clinical outcomes, including survival rates, marginal bone loss (MBL), and complications associated with short implants and standard implants supporting a single crown in the posterior alveolar bone. MATERIAL AND METHODS: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) principles and was registered with PROSPERO (CRD42018112978). The authors identified eligible trials published before August 2019 by searching PubMed, EMBASE, and the Cochrane Library. Only randomized controlled trials (RCTs) were included in the study, and quality assessment was performed by using the Cochrane Collaboration Risk of Bias tool. Relevant information was extracted by using a standardized form, and a meta-analysis was performed by using a software program. RESULTS: A total of 1954 references were identified. Five eligible trials were included in the quantitative synthesis. The survival rate of the short implants (≤6 mm) was similar to that of longer implants (>6 mm) in the short term (P=.72; RR: 0.99; 95% CI: 0.97-1.02); however, long-term follow-up showed that short implants had a poorer survival rate than standard implants (P=.01; RR: 0.94; 95% CI: 0.90-0.99). There was no significant difference in the MBL (P=.94; MD: 0.00; 95% CI: -0.10 to 0.11). CONCLUSIONS: The present study suggested that, although short implants have a higher crown-to-implant (C/I) ratio, they do not affect MBL. However, long-term follow-up comparisons indicated that short implants (≤6 mm) have a poorer survival rate than standard implants (>6 mm) (P=.01). Nonsplinted crowns supported by short implants should be used with caution in the posterior alveolar bone.

Fabrication of three-dimensional nanofibrous gelatin scaffolds using one-step crosslink technique.

Electrospun nanofibers have been considered to be an ideal scaffold for tissue engineering, because of the extracellular-matrix-like structure and the well-controlled fabrication. Here, a new method was used to fabricate electrospun three-dimensional macroporous nanofibrous gelatin scaffolds in ethanol bath by one-step crosslink with glutaraldehyde. The mean diameter of the one-step crosslinked fibers was significantly smaller than that of the traditional two-step crosslinked fibers (p < 0.05), and scaffolds prepared by one-step crosslink were fluffy and porous. No significant difference was found in the degradation rates for both fibers within 14 days. After immersion in PBS for 14 days, numerous two-step crosslinked fibers merged together. By contrast, the morphology and macroporous structure of one-step crosslinked fibers showed no evident change and were generally maintained. Approximate crosslinking degrees of the two-step and one-step crosslinked gelatin fibers were 40% and 54%, respectively (p < 0.05). Results from fluorescence microscopy and hematoxylin-eosin staining showed that MC3T3-E1 subclone four cells were distributed more evenly and diversely in the one-step crosslinked fiber scaffolds. The one-step crosslinked fibers enhanced the proliferation and differentiation potential of MC3T3-E1 cells. Furthermore, one-step crosslinked fibers were beneficial in repairing defects in the skulls of rats. Thus, one-step crosslink by glutaraldehyde in ethanol bath is a cost-effective and simple method to fabricate three-dimensional macroporous nanofiberous scaffolds. This technique retains the morphology and structure of the gelatin fibers, and enhances the biological performance of scaffolds in vitro and in vivo.

Establishment of 3D culture and induction of osteogenic differentiation of pre-osteoblasts using wet-collected aligned scaffolds.

Aligned fibrous scaffolds have attracted much interest in bone tissue engineering, because they are supposed to induce osteogenic differentiation. For the first time, aligned silk fibroin nanofibres were loosely packed using a novel wet-collection electrospinning method. Moreover, three-dimensional (3D) culture of MC3T3-E1 pre-osteoblasts was established on these fibrous scaffolds. Physicochemical properties of the scaffolds and the behaviour of MC3T3-E1 pre-osteoblasts on the scaffolds were analysed and compared with scaffolds obtained using traditional method. Ethanol bath improved the uniformity and alignment of the fibres and increased the thickness and porosity of the scaffolds. Structures of the fibres were well maintained after immediate crosslinking in ethanol. Cells on the wet-collected scaffolds exhibited more ordered arrangement and elongated morphology as well as faster and deeper infiltration. The ordered infiltration resulted in the establishment of the 3D culture of cells, promoting proliferation and osteogenic differentiation of the pre-osteoblasts. Thus, the wet-collected aligned scaffolds with improved topographical and physicochemical properties presents significant potential application in bone regeneration.

Esthetic Restoration of Multiple Congenitally Missing Anterior Teeth with Oral Implants: A Clinical Case Report.

Having multiple congenitally missing anterior teeth heavily influences the patient's countenance and pronunciation. There are few reports on the esthetic restoration of such situations with oral implants. This clinical case history report presents a multidisciplinary approach to treat a young woman with multiple congenitally missing anterior teeth using implant-supported prostheses. The treatment steps and clinical implications are discussed.

The Effect of Tumour Necrosis Factor-α on Periodontal Ligament Stem Cell Differentiation and the Related Signaling Pathways.

Periodontal regeneration plays an integral role in the treatment of periodontal diseases, with important clinical significance for the preservation and functional recovery of affected teeth. Periodontal ligament stem cells (PDLSCs), which were found in the periodontal ligament tissues possessing properties of pluripotency and self-renewing, could repair damaged periodontium with great promise. However, in a chronic inflammatory micro-environment, these cells suffered from reduced capacity to differentiate and regenerate. There has been a growing appreciation that tumour necrosis factor-α (TNF-α) in periodontal tissues drives cellular responses to chronic periodontitis. Several new advances, including an increased understanding of the mechanism of interaction between TNF-α and PDLSCs provides insight into inflamed cell regeneration, which in turn reveal strategies to improve the effectiveness of therapy. Here we gave a comprehensive review on the role of TNF-α in chronic periodontitis, its effect on PDLSCs differentiation and periodontal regeneration, related signaling pathways and concluded with future perspectives of research on PDLSCs-based periodontal tissue regeneration.

Incorporation of magnesium ions into photo-crosslinked alginate hydrogel enhanced cell adhesion ability.

Photo-crosslinked alginate hydrogel attracts wide interest in tissue engineering because of its excellent controllability and stability. However, its highly hydrophilic property makes cell adhesion difficult. Plenty of studies have confirmed that magnesium ions (Mg(2+) ) can efficiently improve the attachment of osteoblasts. In this study, for the first time, we fabricated a durable, crosslinked, alginate hydrogel with a dual-crosslinking network. Photo-crosslinked alginate hydrogel was chosen as the basic backbone, and various amounts of Mg(2+) were incorporated into the hydrogel through ionic crosslinking. The results showed that the physicochemical properties of the hydrogels, including surface structure, composition, swelling ratio, ion release and elastic modulus, could be well tuned by controlling the amount of Mg(2+) incorporated. In addition, a certain amount of Mg(2+) significantly improved the attachment and spread of osteoblasts on the hydrogels. These characteristics make Mg(2+) -incorporated photo-crosslinked alginate hydrogel a promising scaffold for bone tissue engineering.

Effects of preparation methods on the bone formation potential of apatite-coated chitosan microspheres.

To investigate the effects of preparation methods on the bone formation potential of apatite-coated chitosan microspheres, coacervate precipitation method and emulsion cross-linking method were chosen to prepare chitosan microspheres, and then apatite coatings were deposited using simulated body fluid. Rat bone marrow-derived mesenchymal stem cells (BMSCs) were seeded on these microspheres. Cell adhesion, proliferation, and differentiation potential were monitored. For in vivo analysis, some cell/microsphere constructs were implanted in the subcutaneous pockets of male Wistar rats. After 3, 6, 12 weeks, the samples were retrieved and stained with hematoxylin and eosin (HE). Some cell/microsphere constructs were implanted in the calvarial defects of rats. Micro-CT and HE analysis were performed to analyze the new bone formation. It was found that BMSCs on apatite-coated emulsion cross-linked microspheres (EM1) exhibited better proliferation and differentiation than cells on apatite-coated coacervate-precipitated microspheres. The in vivo results showed that no bone was observed in ectopic areas. While in calvarial defects, both histological slices and Micro-CT images demonstrated that a substantial amount of new bone was formed in the EM1/BMSCs construct. These data suggest that preparation methods do exert great influence on the in vitro cell behaviors and in vivo orthotopic bone regeneration of apatite-coated chitosan microspheres. Appropriate method should be considered when preparing chitosan microspheres for bone tissue engineering scaffold.

Effects of drying methods on the preparation of dexamethasone-loaded chitosan microspheres.

The purpose of this study was to investigate the effects of drying methods on the preparation of dexamethasone- (Dex-) loaded chitosan microspheres. Two drying methods, namely, air drying and freeze drying, were adopted. The physical properties of the beads were first investigated and then the loading and release of Dex were characterized. Finally, the bioactivity of released Dex was evaluated. The data showed that, compared with freeze-dried beads, air-dried beads were denser and smaller, and had lower swelling ratios, slower degradation rate and greater Rockwell hardness. In terms of drug delivery, air-dried beads had lower encapsulation efficiency and a slower release rate of Dex. Regarding bioactivity, both groups prompted cell differentiation without significant differences. However, Dex released from freeze-dried beads inhibited cell proliferation, while Dex released from air-dried beads did not. Based on these results, we conclude that incorporation of Dex enhanced the osteogenic potential of chitosan microspheres and drying methods did affect the physical properties of the chitosan microspheres, which further influenced the drug loading and release. At the moment, the air-drying method is more appropriate to prepare Dex-loaded chitosan microspheres.

[Cooperative downconversion in Tb (0.7 ) Yb (5) : FOV oxyfluoride nanophase vitroceramics].

The present article reports the infrared quantum cutting study of the nanophase oxyfluoride vitroceramics Tb(0.7)Yb (5.0) : FOV. The visible to infrared fluorescence emission spectra, excitation spectra and fluorescence lifetime were measured carefully. The infrared quantum cutting phenomenon {1([5 D4 --> 7 F6](Tb3+), 2([2 F7/2 --> 2 F5/2](Yb3+)} was analyzed based on the above experiments. It was found that the theoretical quantum cutting efficiency is about 121.35% when 5D4 level is excited by 487.0nm light, and about 136.27% when (5D3, 5G6) levels are excited by 378.0 nm light respectively. Meanwhile, it is first time for the present paper to find a cooperative downconversion phenomenon {2([(5D3, 5G6) --> 5D4] (Tb3+), 1([2 F7/2 --> 2 F5/2] (Yb3+)}. That is, the authors found for the first time that the donor Tb3+ ion releases two pieces of energy [(5D3, 5G6) --> 5D4] of small energy photon to produce a middle energy photon [2 F5/2 --> 2 F7/2] of acceptor Yb3+ ion.