Culturing on decellularized extracellular matrix enhances antioxidant properties of human umbilical cord-derived mesenchymal stem cells

Human umbilical cord-derived mesenchymal stem cells (UC-MSCs) have attracted great interest in clinical application because of their regenerative potential and their lack of ethical issues. Our previous studies showed that decellularized cell-deposited extracellular matrix (ECM) provided an in vivo-mimicking microenvironment for MSCs and facilitated in vitro cell expansion. This study was conducted to analyze the cellular response of UC-MSCs when culturing on the ECM, including reactive oxygen species (ROS), intracellular antioxidative enzymes, and the resistance to exogenous oxidative stress. After decellularization, the architecture of cell-deposited ECM was characterized as nanofibrous, collagen fibrils and the matrix components were identified as type I and III collagens, fibronectin, and laminin. Compared to tissue culture polystyrene (TCPS) plates, culturing on ECM yielded a 2-fold increase of UC-MSC proliferation and improved the percentage of cells in the S phase by 2.4-fold. The levels of intracellular ROS and hydrogen peroxide (H2O2) in ECM-cultured cells were reduced by 41.7% and 82.9%, respectively. More importantly, ECM-cultured UC-MSCs showed enhanced expression and activity of intracellular antioxidative enzymes such as superoxide dismutase and catalase, up-regulated expression of silent information regulator type 1, and suppressed phosphorylation of p38 mitogen-activated protein kinase. Furthermore, a continuous treatment with exogenous 100μM H2O2 dramatically inhibited osteogenic differentiation of UC-MSCs cultured on TCPS, but culturing on ECM retained the differentiation capacity for matrix mineralization and osteoblast-specific marker gene expression. Collectively, by providing sufficient cell amounts and enhancing antioxidant capacity, decellularized ECM can be a promising cell culture platform for in vitro expansion of UC-MSCs.

Nanogel-electrospinning for controlling the release of water-soluble drugs

Application of electrospun fibers for the purpose of loading and controlled release of water-soluble drugs remains a challenge due to their low carrying effect as well as quick and unstable drug release. In this study, we have developed a novel nanogel-electrospinning technology through which more stable loading and prolonged release of water-soluble drugs was achieved. In brief, nanogel particles synthesized from a chloroquine (CQ)-loaded bovine serum albumin (BSA) solution were prepared and then combined with genipin, a crosslinking agent. The nanogel solution was then crosslinked to prepare an electrospinning solution with an inner mesh structure. Finally, the microfibrous membranes were fabricated by electrospinning the solution. Uniform BSA nanogel particles were wrapped in the fiber membrane and the number of particles increased with the increase of BSA and genipin concentrations. In addition to being loaded within the BSA nanogel particles, CQ was distributed in the fibers as well, which could be clearly identified using ultraviolet-visible spectroscopy (UV-Vis). The physical, chemical, and mechanical properties of nanogel-electrospun microfibers were similar to those of microfibers formed through a conventional electrospinning approach. The drug release tests indicated that with the same number of BSA nanogel particles, increased CQ loading resulted in increased initial release of the same. The duration of a single drug release cycle lasted up to 40 days. In conclusion, findings from this study have indicated that nanogel-electrospinning is a convenient and effective technology to achieve controlled long-term release of water-soluble drugs.

PRAME promotes in vitro leukemia cells death by regulating S100A4/p53 signaling

OBJECTIVE

PRAME (Preferentially Expressed Antigen in Melanoma) is a tumor-associated antigen recognized by immunocytes, and it induces cytotoxic T cell-mediated responses in melanoma. PRAME is expressed in a wide variety of tumors, but in contrast with most other tumor-associated antigens, it is also expressed in leukemias. The physiologic role of PRAME remains elusive. Recently, it has found PRAME could be involved in the regulation of cell death in leukemias, but the mechanism of the function is unclear. Here, we confirm that PRAME induces leukemias cell death by regulation of S100A4/p53 signaling.

MATERIALS AND METHODS

The pCDNA3-PRAME plasmid and its control were transfected with the KG-1 cells. The pCDNA3-PRAME transfected KG-1 cells were then transiently transfected with S100A4 cDNA or wt-p53 siRNA. The PRAME siRNA and its control were transfected with the K562 cells. The PRAME siRNA transfected K562 cells were then transiently transfected with S100A4 siRNA or pGMp53-Lu. PRAME, S100A4 and P53 were detected by Western blot assay in different time point. Annexin V/propidium iodide and MTT methods were used to detect apoptosis and cell survival rate.

RESULTS

KG-1 cells overexpressing the PRAME gene significantly induces apoptosis and decreases proliferation in vitro, followed by down-regulation of S100A4 and up-regulation of p53. Up-regulation of S100A4 by S100A4 transfection inhibits PRAME-induced p53 up-regulation. Furthermore, up-regulation of S100A4 by S100A4 transfection or down-regulation of p53 by p53 siRNA transfection reduces apoptosis and increases proliferation in vitro. Knockdown of PRAME in K562 cells significantly increases proliferation in vitro, followed by up-regulation of S100A4 and down-regulation of p53. The downregulation of S100A4 by S100A4 siRNA transfection increased p53 expression. Furthermore, downregulation of S100A4 by S100A4 siRNA transfection or up-regulation of p53 by p53 transfection decreases proliferation in vitro.

CONCLUSIONS

Our results suggest that the leukemias expressing high levels of PRAME has a favorable prognosis. PRAME promotes in vitro leukemia cells death by regulating S100A4/p53 signaling.

Tumor-Triggered Controlled Drug Release from Electrospun Fibers Using Inorganic Caps for Inhibiting Cancer Relapse

A smart, tumor-trigged, controlled drug release using inorganic "caps" with CO3 (2-) functional groups in electrospun fibers is presented for inhibiting cancer relapse. When the drug-loaded intelligent electrospun fibers encounter pathological acidic environments, the inorganic gates react with the acids and produce CO2 gas, which enables water penetration into the core of the fibers to induce rapid drug release.

Melatonin reverses H2 O2 -induced premature senescence in mesenchymal stem cells via the SIRT1-dependent pathway

Mesenchymal stem cells (MSCs) represent an attractive source for stem cell-based regenerative therapy, but they are vulnerable to oxidative stress-induced premature senescence in pathological conditions. We previously reported antioxidant and antiarthritic effects of melatonin on MSCs against proinflammatory cytokines. In this study, we hypothesized that melatonin could protect MSCs from premature senescence induced by hydrogen peroxide (H2 O2 ) via the silent information regulator type 1 (SIRT1)-dependent pathway. In response to H2 O2 at a sublethal concentration of 200 μm, human bone marrow-derived MSCs (BM-MSCs) underwent growth arrest and cellular senescence. Treatment with melatonin before H2 O2 exposure cannot significantly prevent premature senescence; however, treatment with melatonin subsequent to H2 O2 exposure successfully reversed the senescent phenotypes of BM-MSCs in a dose-dependent manner. This result was made evident by improved cell proliferation, decreased senescence-associated β-galactosidase activity, and the improved entry of proliferating cells into the S phase. In addition, treatment with 100 μm melatonin restored the osteogenic differentiation potential of BM-MSCs that was inhibited by H2 O2 -induced premature senescence. We also found that melatonin attenuated the H2 O2 -stimulated phosphorylation of p38 mitogen-activated protein kinase, decreased expression of the senescence-associated protein p16(INK) (4α) , and increased SIRT1. Further molecular experiments revealed that luzindole, a nonselective antagonist of melatonin receptors, blocked melatonin-mediated antisenescence effects. Inhibition of SIRT1 by sirtinol counteracted the protective effects of melatonin, suggesting that melatonin reversed the senescence in cells through the SIRT1-dependent pathway. Together, these findings lay new ground for understanding oxidative stress-induced premature senescence and open perspectives for therapeutic applications of melatonin in stem cell-based regenerative medicine.

Reduced Penetrance of PRRT2 Mutation in a Chinese Family With Infantile Convulsion and Choreoathetosis Syndrome

Paroxysmal kinesigenic dyskinesia is a rare episodic movement disorder that can be isolated or associated with benign infantile seizures as part of choreoathetosis syndrome. Mutations in the PRRT2 gene have been recently identified as a cause of paroxysmal kinesigenic dyskinesia and infantile convulsion and choreoathetosis (ICCA). We reported a PRRT2 heterozygous mutation (c.604-607delTCAC, p.S202Hfs*25) in a 3-generation Chinese family with infantile convulsion and choreoathetosis and paroxysmal kinesigenic dyskinesia. The mutation was present in 5 family members, of which 4 were clinically affected and 1 was an obligate carrier with reduced penetrance of PRRT2. The affected carriers of this mutation presented with a similar type of infantile convulsion during early childhood and developed additional paroxysmal kinesigenic dyskinesia symptoms later in life. In addition, they all had a dramatic clinical response to oxcarbazepine/phenytoin therapy. Reduced penetrance of the PRRT2 mutation in this family could warrant genetic counseling.

Characterization of the First Fungal Glycosyl Hydrolase Family 19 Chitinase (NbchiA) from Nosema bombycis (Nb)

Chitinases (EC 3.2.1.14), as one kind of glycosyl hydrolase, hydrolyze the β-(1,4) linkages of chitin. According to the sequence similarity, chitinases can be divided into glycoside hydrolase family 18 and family 19. Here, a chitinase from Nosema bombycis (NbchiA) was cloned and purified by metal affinity chromatography and molecular exclusion chromatography. Sequence analysis indicated that NbchiA belongs to glycoside hydrolase family 19 class IV chitinase. The optimal pH and temperature of NbchiA are 7.0 and 40 °C, respectively. This purified chitinase showed high activity toward soluble substrates such as ethylene glycol chitin and soluble chitosan. The degradation of chitin oligosaccharides (GlcNAc)(2-5) detected by high-performance liquid chromatography showed that NbchiA hydrolyzed mainly the second glycosidic linkage from the reducing end of (GlcNAc)(3-5). On the basis of structure-based multiple-sequence alignment, Glu51 and Glu60 are believed to be the key catalytic residues. The site-directed mutation analysis revealed that the enzymatic activity was decreased upon mutation of Glu60, whereas mutation of Glu51 totally abolished the enzymatic activity. This is the first report of a GH19 chitinase in fungi and in Microsporidia.

Nosema sp. PM-1, a new isolate of microsporidian from infected Papilio machaon Linnaeus, based on ultrastructure and molecular identification

A new microsporidium, Nosema sp. PM-1, was first isolated from Papilio machaon Linnaeus. The spore shape of the PM-1 isolate was a long oval with an average size of 3.22 μm × 1.96 μm. Ultrastructure observation showed that PM-1 had a typical Nosema common diplokaryotic nuclei structure with 10-13 polar filament coils, spore wall, plasma membrane, and anchoring disk. The complete rRNA gene sequences were obtained by polymerase chain reaction amplification and each rRNA unit was arrayed as follows: 5'-LSU (2497 bp)-ITS (179 bp)-SSU (1232 bp)-IGS (278 bp)-5S (115 bp)-3', which was the same as typical Nosema. The phylogenetic trees of rRNA, DNA-directed RNA polymerase II subunit, and tubulin genes all show that PM-1 was a sister to the clade comprising Nosema bombycis, Nosema spodopterae, and Nosema sp. PX1. The spore morphology, ultrastructure, and complete rRNA structure indicate that this isolate assigned to the ˝true˝ Nosema group, can parasitized in Papilio machaon Linnaeus, which provides a wider host range for Nosema.

Identification and characterisation of tobacco microRNA transcriptome using high-throughput sequencing

MicroRNAs (miRNAs) are post-transcriptional regulators that are involved in numerous biological processes in plants. In this study, we investigate miRNAs in Honghua Dajinyuan, an agronomically important species of tobacco in China. Here, we report a comprehensive analysis of miRNA expression profiles in the leaf, stem and root using a high-throughput sequencing approach. A total of 165 miRNAs, representing 55 conserved families, and 50 novel miRNAs, representing 19 families, were identified in three libraries. In addition, 12 miRNAs were randomly selected from a differentially expressed conserved miRNA family in three libraries with expression alterations and subjected to qRT-PCR validation. Of these, the expression level of nta-miR167d is highly enriched in the leaf tissue. In addition, the expression level of nta-miR319a is prominently enriched in the stem, while nta-miR160c is highly enriched in the root. Moreover, the target prediction showed that most of the targets coded for transcription factors that are involved in cellular and metabolic processes. GO analysis showed that most of the targets were involved in organelle function, served binding functions, and take part in cellular and metabolic processes. This study helps shed new light on understanding the role of miRNAs in different parts of the tobacco plant and adds a significant number of novel miRNAs to the tobacco miRNA transcriptome.

Self-coated interfacial layer at organic/inorganic phase for temporally controlling dual-drug delivery from electrospun fibers

Implantable tissue engineering scaffolds with temporally programmable multi-drug release are recognized as promising tools to improve therapeutic effects. A good example would be one that exhibits initial anti-inflammatory and long-term anti-tumor activities after tumor resection. In this study, a new strategy for self-coated interfacial layer on drug-loaded mesoporous silica nanoparticles (MSNs) based on mussel-mimetic catecholamine polymer (polydopamine, PDA) layer was developed between inorganic and organic matrix for controlling drug release. When the interface PDA coated MSNs were encapsulated in electrospun poly(L-lactide) (PLLA) fibers, the release rates of drugs located inside/outside the interfacial layer could be finely controlled, with short-term release of anti-inflammation ibuprofen (IBU) for 30 days in absence of interfacial interactions and sustained long-term release of doxorubicin (DOX) for 90 days in presence of interfacial interactions to inhibit potential tumor recurrence. The DOX@MSN-PDA/IBU/PLLA hybrid fibrous scaffolds were further found to inhibit proliferation of inflammatory macrophages and cancerous HeLa cells, while supporting the normal stromal fibroblast adhesion and proliferation at different release stages. These results have suggested that the interfacial obstruction layer at the organic/inorganic phase was able to control the release of drugs inside (slow)/outside (rapid) the interfacial layer in a programmable manner. We believe such interface polymer strategy will find applications in where temporally controlled multi-drug delivery is needed.

A monoclonal antibody that tracks endospore formation in the microsporidium Nosema bombycis

Nosema bombycis, the first identified microsporidium, is a destructive pathogen of the silkworm Bombyx mori and causes severe worldwide economic losses in sericulture. Major microsporidian structural proteins, such as the spore wall protein (SWP), are known to be involved in host invasion. In this study, the reactivity of the monoclonal antibody 2B10 was tested against an endospore protein of N. bombycis with a molecular weight size at 50-kDa, using Western blotting. The antigen was purified after immunoprecipitation and was further identified as EOB13320 according to MALDI-TOF MS assay. We found that EOB13320 locates to the surface of the different developmental stages of the parasite, mostly the sporoblast stage and the mature spore after immunoelectron microscopy examination. EOB13320 was also widely distributed in the developing endospore, especially at the sporoblast stage. This endospore protein also accumulated in the cytoplasm of both the merogony and sporoblast stages. These results imply that EOB13320 detected by monoclonal antibody 2B10 is expressed throughout the life cycle of the parasite, notably during the stage when the endospore is formed, and that this protein is important for spore-coat formation and parasite maintenance. Our study could be instrumental in the understanding of spore wall formation and will help to gain greater insight into the biology of this parasite.

Correction: A hierarchical, stretchable and stiff fibrous biotemplate engineered using stagger-electrospinning for augmentation of rotator cuff tendon-healing

Correction for 'A hierarchical, stretchable and stiff fibrous biotemplate engineered using stagger-electrospinning for augmentation of rotator cuff tendon-healing' by Song Zhao et al., J. Mater. Chem. B, 2015, 3, 990-1000.

Prevalence and awareness of diabetes mellitus among a rural population in China: results from Liaoning Province

AIM

To clarify the diabetes prevalence trends among the rural population in northern China.

METHODS

All eligible permanent residents aged ≥ 35 years in selected rural villages of Liaoning province were invited to participate in the study. A total of 11 600 people completed all questionnaires and were included in the study. The response rate was 85.3%. Fasting plasma glucose levels were measured after at least 12 h of fasting and diabetes was diagnosed according to WHO criteria, i.e. fasting plasma glucose ≥ 7 mmol/l and/or being on treatment for diabetes. Impaired fasting glucose was defined according to the 1997 and the 2010 American Diabetes Association (ADA) criteria (6.1-6.9 and 5.6-6.9 mmol/l, respectively). Previous diagnoses of diabetes were assessed on the basis of self-reports.

RESULTS

The prevalence of diabetes among adults in the rural population was 10.6% (10.0% in men and 11.1% in women). The prevalence of impaired fasting glucose was 13.0 and 36.1% according to the 1997 and the 2010 ADA criteria, respectively. The prevalence of previously diagnosed diabetes was 4.3% among the whole population (3.3% in men and 5.1% in women). The prevalence of previously diagnosed diabetes was 34.8% in men and 50.2% in women. Only 29.6% of men and 42% of women with diabetes had taken oral hypoglycaemic agents or insulin to lower their blood sugar. In multivariate analysis, age, drinking habits, BMI, dyslipidaemia and family history of diabetes were identified as independent risk factors for diabetes, and occupational physical activity, smoking and lean meat intake were identified as independent protective factors for diabetes.

CONCLUSIONS

The prevalence of diabetes and impaired fasting glucose were found to be high in this rural population. Although the rate of treatment of people with diabetes has increased, the glycaemic control rate was still at a low level.

Micromotors to capture and destroy anthrax simulant spores

Towards addressing the need for detecting and eliminating biothreats, we describe a micromotor-based approach for screening, capturing, isolating and destroying anthrax simulant spores in a simple and rapid manner with minimal sample processing. The B. globilli antibody-functionalized micromotors can recognize, capture and transport B. globigii spores in environmental matrices, while showing non-interactions with excess of non-target bacteria. Efficient destruction of the anthrax simulant spores is demonstrated via the micromotor-induced mixing of a mild oxidizing solution. The new micromotor-based approach paves a way to dynamic multifunctional systems that rapidly recognize, isolate, capture and destroy biological threats.

Saccharides and temperature dual-responsive hydrogel layers for harvesting cell sheets

A novel non-invasive approach for harvesting cell sheets was demonstrated just by adding saccharide biomolecules into cell culture medium and without reduction of the temperature.

Synergistic mediation of tumor signaling pathways in hepatocellular carcinoma therapy via dual-drug-loaded pH-responsive electrospun fibrous scaffolds

A novel pH-sensitive electrospun composite PLLA fibrous scaffold was developed with long-term anti-cancer drug release and short-term anti-inflammation drug release for liver cancer therapy.

A hierarchical, stretchable and stiff fibrous biotemplate engineered using stagger-electrospinning for augmentation of rotator cuff tendon-healing

The regeneration of fibrocartilage at the tendon-bone insertion site in rotator cuff tears (RCTs) is challenging due to the complexity of its composition and mechanical properties. In this study, hierarchical, stretchable and stiff fibrous scaffolds composed of microfibers of poly(ε-caprolactone) (PCL) and nanofibers of chitosan (CS) were fabricated using stagger-electrospinning for the augmentation of RCT-healing. It was found that the composite PCL-CS scaffolds had significantly improved strength and failure strain compared to the control CS scaffolds and increased stiffness compared to the control PCL scaffolds. These scaffolds also showed enhanced hydrophilicity, water absorption and a faster degradation rate compared to the PCL scaffolds. Moreover, they demonstrated better fibroblast attachment and proliferation compared to the PCL scaffolds. Radiological and histological analysis revealed that the PCL-CS scaffolds enhanced new bone formation (mineralization) and collagen and glycosaminoglycan expression (major components of extracellular matrix) compared to the PCL scaffolds. Furthermore, the torn tissues at the tendon-bone insertion site regenerated with the PCL-CS scaffolds showed higher strength and failure strain as well as stiffness compared to those repaired using only the PCL scaffolds. The above mentioned results suggest that the hierarchical, stretchable and stiff fibrous scaffolds engineered using stagger-electrospinning have great potential for the augmentation of RCT-healing.

Extracellular matrix modulates the biological effects of melatonin in mesenchymal stem cells

Both self-renewal and lineage-specific differentiation of mesenchymal stem cells (MSCs) are triggered by their in vivo microenvironment including the extracellular matrix (ECM) and secreted hormones. The ECM may modulate the physiological functions of hormones by providing binding sites and by regulating downstream signaling pathways. Thus, the purpose of this study was to evaluate the degree of adsorption of melatonin to a natural cell-deposited ECM and the effects of this interaction on the biological functions of melatonin in human bone marrow-derived MSCs (BM-MSCs). The fibrillar microstructure, matrix composition, and melatonin-binding affinity of decellularized ECM were characterized. The cell-deposited ECM improved melatonin-mediated cell proliferation by 31.4%, attenuated accumulation of intracellular reactive oxygen species accumulation, and increased superoxide dismutase (SOD) mRNA and protein expression. Interaction with ECM significantly enhanced the osteogenic effects of melatonin on BM-MSCs by increasing calcium deposition by 30.5%, up-regulating osteoblast-specific gene expression and down-regulating matrix metalloproteinase (MMP) expression. The underlying mechanisms of these changes in expression may involve intracellular antioxidant enzymes, because osteoblast-specific genes were down-regulated, whereas MMP expression was up-regulated, in the presence of SOD-specific inhibitors. Collectively, our findings indicate the importance of native ECM in modulating the osteoinductive and antioxidant effects of melatonin and provide a novel platform for studying the biological actions of growth factors or hormones in a physiologically relevant microenvironment. Moreover, a better understanding of the enhancement of MSC growth and osteogenic differentiation resulting from the combination of ECM and melatonin could improve the design of graft substitutes for skeletal tissue engineering.

New evidence on the relationship between Microsporidia and Fungi: a genome-wide analysis by DarkHorse software

Microsporidia are a group of obligate intracellular eukaryotic parasites that infect a wide variety of species, including humans. Phylogenetic analysis indicates a relationship between the Microsporidia and the Fungi. However, most results are based on the analysis of relatively few genes. DarkHorse analysis involves the transformation of BLAST results into a lineage probability index (LPI) value and allows for the comparison of genes for an entire genome with those of other genomes. Thus, we can see which genes from the microsporidia score most closely based on the LPI with other eukaryotic organisms. In this analysis, we calculated the LPI for each gene from the genomes of 7 Microsporidia, Antonospora locustae, Enterocytozoon bieneusi, Encephalitozoon cuniculi, Encephalitozoon intestinalis, Nosema bombycis, Nosema ceranae, and Nematocida parisii, to analyze the genetic relationships between Microsporidia and other species. It was found that many (91%) genes were most closely correlated with genes from other microsporidial genomes and had the highest mean LPI (0.985), indicating a monophyletic origin of the Microsporidia. In a subsequent analysis, we excluded the other Microsporidia from the analysis to look for relationships before the divergence of Microsporidia, and found that 43% of the microsporidial genes scored highest with fungal genes, and a higher mean LPI was found with Fungi than with other kingdoms, suggesting that Microsporidia is closely related to Fungi at the genomic level. Microsporidial genes were functionally clustered based on the KOG (Eukaryotic COG) database, and the possible lineages for each gene family were discussed in concert with the DarkHorse results.