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Emerging evidence indicates that in myelodysplastic syndromes (MDS),the bone marrow (BM) microenvironment may also contribute to the ineffective,malignant haematopoiesis in addition to the intrinsic abnormalities of haematopoietic stem precursor cells (HSPCs). The BM microenvironment influences malignant haematopoiesis through indirect mechanisms,but the processes by which the BM microenvironment directly contributes to MDS initiation and progression have not yet been elucidated. Our previous data showed that BM-derived stromal cells (BMSCs) from MDS patients have an abnormal expression of focal adhesion kinase (FAK). In this study,we characterise the morpho-phenotypic features and the functional alterations of BMSCs from MDS patients and in FAK knock-downed HS-5 cells. The decreased expression of FAK or its phosphorylated form in BMSCs from low-risk (LR) MDS directly correlates with BMSCs' functional deficiency and is associated with a reduced level of haemoglobin. The downregulation of FAK in HS-5 cells alters their morphology,proliferation,and differentiation capabilities and impairs the expression of several adhesion molecules. In addition,we examine the CD34+ healthy donor (HD)-derived HSPCs' properties when co-cultured with FAK-deficient BMSCs. Both abnormal proliferation and the impaired erythroid differentiation capacity of HD-HSPCs were observed. Together,these results demonstrate that stromal adhesion mechanisms mediated by FAK are crucial for regulating HSPCs' homeostasis. View Publication

Background Nab-paclitaxel has been widely used in treating breast cancer and pancreatic patients for its low toxicity and high efficiency. However,its role in gastric cancer (GC) remains ambiguous. The aim of our study was to test the anti-tumor activity of nab-paclitaxel using GC patient-derived organoids. Methods By using the organoid culture system,we describe the establishment of human gastric cancer organoid lines from surgical samples of three patients with gastric cancer. The consistency of these organoids with original cancer tissues was evaluated by histopathological examination. The characteristics of the cancer organoids were tested using immunofluorescence (IF) staining. Using organoids,the anti-tumor efficiencies of nab-paclitaxel,5-Fu and epirubicin were compared by CCK8 assay and Annexin V-FITC/PI staining. Results Three organoids were successfully established and passaged. The morphology of the established GC organoids was consistent with original cancer tissues. The IC50 of nab-paclitaxel was 3.68 $\mu$mol/L in hGCO1,2.41 $\mu$mol/L in hGCO2 and 2.91 $\mu$mol/L in hGCO3,which was significantly lower than those of 5-FU (72.99 $\mu$mol/L in hGCO1,28.32 $\mu$mol/L in hGCO2 and 2.91 $\mu$mol/L in hGCO3) and epirubicin (25.85$\mu$mol/L in hGCO1,15.15 $\mu$mol/L in hGCO2 and 7.60 $\mu$mol/L in hGCO3). When each organoid lines were treated with nab-paclitaxel for increasing period of time,the percentage of the apoptotic cells in each organoid increased accordingly. Conclusion Nab-paclitaxel showed strong anti-tumor activity and had the potential to become front-line drug for treating GC patients. Gastric cancer organoid may be a good tool to predict in vivo response to drugs. View Publication

The proteasome inhibitor bortezomib is the most successfully applied chemotherapeutic drug for treating multiple myeloma. However,its clinical efficacy reduced due to resistance development. The underlying molecular mechanisms of bortezomib resistance are poorly understood. In this study,by combining in silico analysis and sgRNA library based drug resistance screening assay,we identified SENP2 (Sentrin/SUMO-specific proteases-2) as a bortezomib sensitive gene and found its expression highly downregulated in bortezomib resistant multiple myeloma patient's samples. Furthermore,down regulation of SENP2 in multiple myeloma cell line RPMI8226 alleviated bortezomib induced cell proliferation inhibition and apoptosis,whereas,overexpression of SENP2 sensitized these cells to bortezomib treatment. We further demonstrate that knockdown of SENP2 in RPMI8226 cells increased SUMO2 conjugated I$\kappa$B$\alpha$ that resulted in the activation of NF-$\kappa$B. Taken together,we report that silencing of SENP2 and consequent activation of NF-$\kappa$B through the modulation of I$\kappa$B$\alpha$ sumoylation as a novel mechanism inducing bortezomib resistance in multiple myeloma. View Publication

BACKGROUND Recent studies have suggested that both poly(l-lactide-co-1,5-dioxepan-2-one) (or poly(LLA-co-DXO)) and poly(l-lactide-co-$\epsilon$-caprolactone) (or poly(LLA-co-CL)) porous scaffolds are good candidates for use as biodegradable scaffold materials in the field of tissue engineering; meanwhile,their surface properties,such as hydrophilicity,need to be further improved. METHODS We applied several different concentrations of the surfactant Tween 80 to tune the hydrophilicity of both materials. Moreover,the modification was applied not only in the form of solid scaffold as a film but also a porous scaffold. To investigate the potential application for tissue engineering,human bone marrow mesenchymal stem cells (hMSCs) were chosen to test the effect of hydrophilicity on cell attachment,proliferation,and differentiation. First,the cellular cytotoxicity of the extracted medium from modified scaffolds was investigated on HaCaT cells. Then,hMSCs were seeded on the scaffolds or films to evaluate cell attachment,proliferation,and osteogenic differentiation. The results indicated a significant increasing of wettability with the addition of Tween 80,and the hMSCs showed delayed attachment and spreading. PCR results indicated that the differentiation of hMSCs was stimulated,and several osteogenesis related genes were up-regulated in the 3{\%} Tween 80 group. Poly(LLA-co-CL) with 3{\%} Tween 80 showed an increased messenger Ribonucleic acid (mRNA) level of late-stage markers such as osteocalcin (OC) and key transcription factor as runt related gene 2 (Runx2). CONCLUSION A high hydrophilic scaffold may speed up the osteogenic differentiation for bone tissue engineering. View Publication

Human osteogenic progenitors are not precisely defined,being primarily studied as heterogeneous multipotent cell populations and termed mesenchymal stem cells (MSCs). Notably,select human pericytes can develop into bone-forming osteoblasts. Here,we sought to define the differentiation potential of CD146+ human pericytes from skeletal and soft tissue sources,with the underlying goal of defining cell surface markers that typify an osteoblastogenic pericyte. CD146+CD31-CD45- pericytes were derived by fluorescence-activated cell sorting from human periosteum,adipose,or dermal tissue. Periosteal CD146+CD31-CD45- cells retained canonical features of pericytes/MSC. Periosteal pericytes demonstrated a striking tendency to undergo osteoblastogenesis in vitro and skeletogenesis in vivo,while soft tissue pericytes did not readily. Transcriptome analysis revealed higher CXCR4 signaling among periosteal pericytes in comparison to their soft tissue counterparts,and CXCR4 chemical inhibition abrogated ectopic ossification by periosteal pericytes. Conversely,enrichment of CXCR4+ pericytes or stromal cells identified an osteoblastic/non-adipocytic precursor cell. In sum,human skeletal and soft tissue pericytes differ in their basal abilities to form bone. Diversity exists in soft tissue pericytes,however,and CXCR4+ pericytes represent an osteoblastogenic,non-adipocytic cell precursor. Indeed,enrichment for CXCR4-expressing stromal cells is a potential new tactic for skeletal tissue engineering. View Publication

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Dental tissue has been acknowledged as an advantaged source for high-quality dental pulp stem cell (DPSC) preparation. However,despite the accomplishment of the separation of DPSCs from permanent teeth and supernumerary teeth,the deficiency of rigorous and systematic clarification on the signatures and efficacy will hinder their prospects in regenerative medicine. In this study,we primitively isolated permanent teeth-derived DPSCs and supernumerary teeth-derived apical papillary stem cells (SCAP-Ss) with parental consent. Immunophenotype of DPSCs and SCAP-Ss was determined by a flow cytometry assay,and the cell viability was verified by multidimensional detections including cell proliferation,cell cycle,apoptosis,and senescence. The migration and clonogenic capacity were examined by a wound healing test and crystal violet staining,respectively. The multilineage differentiation potential was quantitated by utilizing Oil Red O staining and Alizarin Red staining,together with real-time PCR analysis. The efficacy on a mouse hepatic fibrosis model was evaluated by using histologic sections and liver function tests. Herein,we showed that SCAP-Ss exhibited comparable immunophenotype and adipogenic differentiation capacity as DPSCs. However,different from DPSCs,SCAP-Ss exhibited superiority in cell viability and osteogenic differentiation. Simultaneously,injection of DPSCs and SCAP-Ss significantly reduced inflammatory infiltration,enhanced liver-associated gene expression,and finally relieved symptoms of hepatic fibrosis. In conclusion,SCAP-Ss possess preferable characteristics and efficacy on hepatic fibrosis in mice. Our findings suggest that SCAP-Ss are an easily accessible postnatal stem cell source with multifaceted characteristics for regenerative medicine. View Publication

Continual efferocytic clearance of apoptotic cells (ACs) by macrophages prevents necrosis and promotes injury resolution. How continual efferocytosis is promoted is not clear. Here,we show that the process is optimized by linking the metabolism of engulfed cargo from initial efferocytic events to subsequent rounds. We found that continual efferocytosis is enhanced by the metabolism of AC-derived arginine and ornithine to putrescine by macrophage arginase 1 (Arg1) and ornithine decarboxylase (ODC). Putrescine augments HuR-mediated stabilization of the mRNA encoding the GTP-exchange factor Dbl,which activates actin-regulating Rac1 to facilitate subsequent rounds of AC internalization. Inhibition of any step along this pathway after first-AC uptake suppresses second-AC internalization,whereas putrescine addition rescues this defect. Mice lacking myeloid Arg1 or ODC have defects in efferocytosis in vivo and in atherosclerosis regression,while treatment with putrescine promotes atherosclerosis resolution. Thus,macrophage metabolism of AC-derived metabolites allows for optimal continual efferocytosis and resolution of injury. View Publication

Although obesity is known to be critical for cancer development,how obesity negatively impacts antitumor immune responses remains largely unknown. Here,we show that increased fatty acid oxidation (FAO) driven by activated STAT3 in CD8+ T effector cells is critical for obesity-associated breast tumor progression. Ablating T cell Stat3 or treatment with an FAO inhibitor in obese mice spontaneously developing breast tumor reduces FAO,increases glycolysis and CD8+ T effector cell functions,leading to inhibition of breast tumor development. Moreover,PD-1 ligation in CD8+ T cells activates STAT3 to increase FAO,inhibiting CD8+ T effector cell glycolysis and functions. Finally,leptin enriched in mammary adipocytes and fat tissues downregulates CD8+ T cell effector functions through activating STAT3-FAO and inhibiting glycolysis. We identify a critical role of increased oxidation of fatty acids driven by leptin and PD-1 through STAT3 in inhibiting CD8+ T effector cell glycolysis and in promoting obesity-associated breast tumorigenesis. View Publication

Purpose The topical application of exosomes secreted by mesenchymal stem cells (MSC-Exos) on the skin is a very new and interesting topic in the medical field. In this study,we aimed to investigate whether marine sponge Haliclona sp. spicules (SHSs) could effectively enhance the skin delivery of human umbilical cord-derived MSC-Exos (hucMSC-Exos),and further evaluate the topical application of hucMSC-Exos combined with SHSs in rejuvenating photoaged mouse skin. Materials and Methods SHSs were isolated from the explants of sponge Haliclona sp. with our proprietary method,and hucMSC-Exos were prepared from the conditioned medium of hucMSCs using ultracentrifugation. The effects of SHSs on the skin penetration of fluorescently labeled hucMSC-Exos were determined using confocal microscopy in vitro (porcine skin) and in vivo (mouse skin). The therapeutic effects of hucMSC-Exos coupled with SHSs against UV-induced photoaging in mice were assessed by using microwrinkles analysis,pathohistological examination and real-time RT-PCR. We also tested the skin irritation caused by the combination of hucMSC-Exos and SHSs in guinea pigs. Results In vitro results showed that hucMSC-Exos could not readily penetrate through porcine skin by themselves. However,SHSs increased the skin absorption of exosomes by a factor of 5.87 through creating microchannels. Similar penetration enhancement of hucMSC-Exos was observed after SHSs treatment in mice. The combined use of hucMSC-Exos and SHSs showed significant anti-photoaging effects in mice,including reducing microwrinkles,alleviating histopathological changes,and promoting the expression of extracellular matrix constituents,whereas hucMSC-Exos alone produced considerably weaker effects. Skin irritation test showed that the combination of hucMSC-Exos and SHSs caused slight irritation,and the skin recovered shortly. Conclusion SHSs provide a safe and effective way to enhance the skin delivery of MSC-Exos. Moreover,the combination of MSC-Exos and SHSs may be of much use in the treatment of photoaging. View Publication

Stress granules (SGs) are non-membrane-bound RNA-protein granules that assemble through phase separation in response to cellular stress. Disturbances in SG dynamics have been implicated as a primary driver of neurodegenerative diseases,including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD),suggesting the hypothesis that these diseases reflect an underlying disturbance in the dynamics and material properties of SGs. However,this concept has remained largely untestable in available models of SG assembly,which require the confounding variable of exogenous stressors. Here we introduce a light-inducible SG system,termed OptoGranules,based on optogenetic multimerization of G3BP1,which is an essential scaffold protein for SG assembly. In this system,which permits experimental control of SGs in living cells in the absence of exogenous stressors,we demonstrate that persistent or repetitive assembly of SGs is cytotoxic and is accompanied by the evolution of SGs to cytoplasmic inclusions that recapitulate the pathology of ALS-FTD. Editorial note This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter). View Publication

Endogenous repair of osteochondral defect is usually limited by the insufficient number of cells in the early stage and incomplete cell differentiation in the later stage. The development of drug delivery systems for sequential release of pro-migratory and pro-chondrogenic molecules to induce endogenous bone marrow-derived mesenchymal stem cells (BMSCs) recruitment and chondrogenic differentiation is highly desirable for in situ osteochondral regeneration. In this study,a novel,all-silk-derived sequential delivery system was fabricated by incorporating the tunable drug-loaded silk fibroin (SF) nanospheres into a SF porous matrix. The loading efficiency and release kinetics of biomolecules depended on the initial SF/polyvinyl alcohol (PVA) concentrations (0.2{\%},1{\%} and 5{\%}) of the nanospheres,as well as the hydrophobicity of the loaded molecules,resulting in controllable and programmed delivery profiles. Our findings indicated that the 5{\%} nanosphere-incorporated matrix showed a rapid release of E7 peptide during the first 120 h,whereas the 0.2{\%} nanosphere-incorporated matrix provided a slow and sustained release of Kartogenin (KGN) longer than 30 days. During in vitro culture of BMSCs,this functional SF matrix incorporated with E7/KGN nanospheres showed good biocompatibility,as well as enhanced BMSCs migration and chondrogenic differentiation through the release of E7 and KGN. Furthermore,when implanted into rabbit osteochondral defect,the SF nanosphere matrix with sequential E7/KGN release promoted the regeneration of both cartilage and subchondral bone. This work not only provided a novel all-silk-derived drug delivery system for sequential release of molecules,but also a functional tissue-engineered scaffold for osteochondral regeneration. View Publication