Extracellular vesicles: a rising star for therapeutics and drug delivery.

Extracellular vesicles (EVs) are nano-sized, natural, cell-derived vesicles that contain the same nucleic acids, proteins, and lipids as their source cells. Thus, they can serve as natural carriers for therapeutic agents and drugs, and have many advantages over conventional nanocarriers, including their low immunogenicity, good biocompatibility, natural blood-brain barrier penetration, and capacity for gene delivery. This review first introduces the classification of EVs and then discusses several currently popular methods for isolating and purifying EVs, EVs-mediated drug delivery, and the functionalization of EVs as carriers. Thereby, it provides new avenues for the development of EVs-based therapeutic strategies in different fields of medicine. Finally, it highlights some challenges and future perspectives with regard to the clinical application of EVs.

Anti-Parkinsonian Therapy: Strategies for Crossing the Blood-Brain Barrier and Nano-Biological Effects of Nanomaterials.

Parkinson's disease (PD), a neurodegenerative disease that shows a high incidence in older individuals, is becoming increasingly prevalent. Unfortunately, there is no clinical cure for PD, and novel anti-PD drugs are therefore urgently required. However, the selective permeability of the blood-brain barrier (BBB) poses a huge challenge in the development of such drugs. Fortunately, through strategies based on the physiological characteristics of the BBB and other modifications, including enhancement of BBB permeability, nanotechnology can offer a solution to this problem and facilitate drug delivery across the BBB. Although nanomaterials are often used as carriers for PD treatment, their biological activity is ignored. Several studies in recent years have shown that nanomaterials can improve PD symptoms via their own nano-bio effects. In this review, we first summarize the physiological features of the BBB and then discuss the design of appropriate brain-targeted delivery nanoplatforms for PD treatment. Subsequently, we highlight the emerging strategies for crossing the BBB and the development of novel nanomaterials with anti-PD nano-biological effects. Finally, we discuss the current challenges in nanomaterial-based PD treatment and the future trends in this field. Our review emphasizes the clinical value of nanotechnology in PD treatment based on recent patents and could guide researchers working in this area in the future.

A versatile and multifunctional metal-organic framework nanocomposite toward chemo-photodynamic therapy.

Previously most of the applications of targeting components have been based on the enhanced permeability and retention effect achieved using folic acid, which consider the side effects of the targeting components to some extent. Herein, we report a new strategy to decorate the surface of MOFs using a pemetrexed (MTA) targeting molecule, affording a new drug delivery system of ALA@UIO-66-NH-FAM/MTA (ALA = 5-amino-levulinic acid and FAM = 5-carboxyfluorescein). The confocal microscopy and flow cytometry results showed that ALA@UIO-66-NH-FAM/MTA presented a better targeting effect compared to ALA@UIO-66-NH-FAM/FA (FA = folic acid) and indicated a gradually increasing tendency of the targeting effect with the increasing expression of folate receptors on the tumor cell cytomembrane. Furthermore, the cytotoxicity experiment indicates that the combination of chemotherapy and photodynamic therapy is a more effective therapy model than single chemotherapy and photodynamic therapy. This work demonstrates the first attempt at folic acid antagonist (MTA) modification for NMOFs, providing a new concept for the design of MOFs with folate receptor targeting capacity for clinical applications.

Clinical outcomes of treatment with cage-shaped demineralized bone plus local bone grafts vs. autogenous iliac crest bone grafts in instrumented single-level lumbar fusion: A retrospective cohort study.

The aim of the present study was to compare the clinical outcomes of cage-shaped demineralized bone plus local bone grafts (CDBLG) with those of autogenous iliac crest bone grafts (ICBG) implanted for the treatment of single-level lumbar intervertebral disc degenerative diseases. A total of 69 cases of degenerative spinal disorder treated between January 2011 and December 2013 were retrospectively analyzed. Of these, 44 were treated with CDBLG and 25 with autogenous ICBG. All fusions were instrumented single level. Fusion was assessed after 6, 12 and 24 months by X-ray and CT scans post-operatively. Clinical outcomes were determined during follow-up and assessments included the Oswestry Disability Index, Visual Analogue Scale for back and leg pain and the Short Form-36 general health survey physical component summary. The results indicated that the overall fusion rate at 24 months post-operatively was higher in the ICBG group compared with that in the CDBLG group, although not significantly (P>0.05). All other outcome measures were significantly improved in the two groups after the surgery (P<0.05), but no significant differences were observed between the two groups (P>0.05). Blood loss and mean duration of surgery in the CDBLG group were significantly lower compared with those in the ICBG group (P<0.05). In conclusion, CDBLG achieved a similar fusion rate and clinical outcome as ICBG but was associated with significantly reduced blood loss and mean duration of surgery. In conclusion, the present study provided CDBLG bone graft as an alternative option for single-level fusion.

Photocatalytic and Ferric Ion Sensing Properties of a New Three-Dimensional Metal-Organic Framework Based on Cuboctahedral Secondary Building Units.

A new three-dimensional microporous metal-organic framework based on Zn(II) clusters with the formula {[Zn7(NDC)5.5(µ4-OH)3]·7DMF} n (1) (H2NDC = 1,4-naphthalenedicarboxylic acid) had been synthesized and characterized. The MOF 1 displays an uncommon bsn topology, which is based on a unique heptanuclear Zn7(OH)3(CO2)11 cluster as a secondary building unit. The MOF had been employed as a photocatalyst for the photodegradation of model organic dyes rhodamine B and methyl violet in light. The results of photocatalytic experiments showed that 1 can successfully be employed as the photocatalyst for the benign decomposition of these dyes. A mechanism for the photcatalysis exhibited by 1 had been proposed using the results of density of states (DOS) and partial DOS calculations. The fluorescence properties of the MOF have been investigated, which revealed that 1 could be exploited as the luminescent sensor to recognize Fe3+ ions with perceptible quenching (K sv = 6.55 × 104 M-1) and a limit of detection of 1.16 ppm.

[Ectopic osteogenesis of immortalized human bone marrow mesenchymal stem cells and heterogeneous bone].

OBJECTIVE: To provide the seed cells for bone tissue engineering, to establish immortalized human bone marrow mesenchymal stem cells (MSCxj) and to investigate the ectopic osteogenesis of MSCxj. METHODS: MSCxjs of the 35th and 128th generations were maintained and harvested when the cell density reached 2 x 10(9). Then, these cells were co-cultured with heterogeneous bone scaffold in groups A (the 35th generation, n = 12) and group B (the 128th generation, n = 12); heterogeneous bone alone was used in group C (n = 12). The cell proliferation was observed by scanning electron microscopy (SEM) after 48 hours and 18 days of osteogenic induction culture. The complex was implanted subcutaneously through a 3-mm-incision at both sides of the back in 18 nude mice. Tetracycline labeling was performed before the animals were sacrificed. Tetracycline fluorescence staining, HE staining, ponceau staining, and immunohistochemistry staining for osteocalcin were performed at 4, 8, and 12 weeks after transplantation; the morphologic quantitative analysis was made. RESULTS: After 48 hours, SEM showed that MSCxjs adhered to heterogeneous bone and grew well; after 18 days, a large number of new filamentous extracellular matrix and small granules were found to cover the cells. The results of tetracycline fluorescence staining, HE staining, and ponceau staining in groups A and B showed that the osteogenesis was not obvious at 4 weeks after transplantation; osteoid matrix deposition was noted around and in the heterogeneous bone at 8 weeks; and osteogenesis was increased at 12 weeks. There was no significant difference in bone formation between groups A and B. Osteogenesis was not observed in group C. The osteocalcin expressions were positive in groups A and B. The bone ingrown percentages of groups A and B were 5.64% +/- 2.68% and 4.92% +/- 2.95% at 8 weeks, and 13.94% +/- 2.21% and 14.34% +/- 3.46% at 12 weeks, showing significant differences between 8 weeks and 12 weeks at the same group (P < 0.05) and no significant difference between groups A and B at the same time (P > 0.05). CONCLUSION: MSCxj has favorable abilities of ectopic osteogenesis and can be applied as seeded cells in bone tissue engineering.

Identification and characterization of bZIP-type transcription factors involved in carrot (Daucus carota L.) somatic embryogenesis.

Seed dormancy is an important adaptive trait that enables seeds of many species to remain quiescent until conditions become favorable for germination. Abscisic acid (ABA) plays an important role in these developmental processes. Like dormancy and germination, the elongation of carrot somatic embryo radicles is retarded by sucrose concentrations at or above 6%, and normal growth resumes at sucrose concentrations below 3%. Using a yeast one-hybrid screening system, we isolated two bZIP-type transcription factors, CAREB1 and CAREB2, from a cDNA library prepared from carrot somatic embryos cultured in a high-sucrose medium. Both CAREB1 and CAREB2 were localized to the nucleus, and specifically bound to the ABA response element (ABRE) in the Dc3 promoter. Expression of CAREB2 was induced in seedlings by drought and exogenous ABA application; whereas expression of CAREB1 increased during late embryogenesis, and reduced dramatically when somatic embryos were treated with fluridone, an inhibitor of ABA synthesis. Overexpression of CAREB1 caused somatic embryos to develop slowly when cultured in low-sucrose medium, and retarded the elongation of the radicles. These results indicate that CAREB1 and CAREB2 have similar DNA-binding activities, but play different roles during carrot development. Our results indicate that CAREB1 functions as an important trans-acting factor in the ABA signal transduction pathway during carrot somatic embryogenesis.

Duplication and adaptive evolution of the COR15 genes within the highly cold-tolerant Draba lineage (Brassicaceae).

Plants have evolved diverse adaptive mechanisms that enable them to tolerate abiotic stresses, to varying degrees, and such stresses may have strongly influenced evolutionary changes at levels ranging from molecular to morphological. Previous studies on these phenomena have focused on the adaptive evolution of stress-related orthologous genes in specific lineages. However, heterogenetic evolution of the paralogous genes following duplication has only been examined in a very limited number of stress-response gene families. The COR15 gene encodes a low molecular weight protein that plays an important role in protecting plants from cold stresses. Although two different copies of this gene have been found in the model species, Arabidopsis thaliana, evolutionary patterns of this small gene family in plants have not been previously explored. In this study, we cloned COR15-like sequences and performed evolutionary analyses of these sequences (including those previously reported) in the highly cold-tolerant Draba lineage and related lineages of Brassicaceae. Our phylogenetic analyses indicate that all COR15-like sequences clustered into four clades that corresponded well to the morphological lineages. Gene conversions were found to have probably occurred before/during the divergence of Brassica and Draba lineage. However, repeated, independent duplications of this gene have occurred in different lineages of Brassicaceae. Further comparisons of all sequences suggest that there have been significant inter-lineage differences in evolutionary rates between the duplicated and original genes. We assessed the likelihood that the differences between two well-supported gene subfamilies that appear to have originated from a single duplication, COR15a and COR15b, within the Draba lineage have been driven by adaptive evolution. Comparisons of their non-synonymous/synonymous substitution ratios and rates of predicted amino acid changes indicate that these two gene groups are evolving under different selective pressures and may be functionally divergent. This functional divergence was confirmed by comparing site-specific shifts in evolution indexes of the two groups of predicted proteins. The evidence of differential selection and possible functional divergence suggests that the duplication may be of adaptive significance, with possible implications for the explosive diversification of the Draba lineage during the cooling Quaternary stages and the following worldwide colonization of arid alpine and artic regions.

Overexpression of a rice OsDREB1F gene increases salt, drought, and low temperature tolerance in both Arabidopsis and rice.

DREB transcription factors play key roles in plant stress signalling transduction pathway, they can specifically bind to DRE/CRT element (G/ACCGAC) and activate the expression of many stress inducible genes. Here, a novel rice DREB transcription factor, OsDREB1F, was cloned and characterised via subtractive suppression hybridisation (SSH) from upland rice. Expression analysis revealed that OsDREB1F gene was induced by salt, drought, cold stresses, and also ABA application, but not by pathogen, wound, and H2O2. Subcellular localization results indicated that OsDREB1F localizes in nucleus. Yeast activity assay demonstrated that OsDREB1F gene encodes a transcription activator, and can specifically bind to DRE/CRT but not to ABRE element. Transgenic plants harbouring OsDREB1F gene led to enhanced tolerance to salt, drought, and low temperature in both rice and Arabidopsis. The further characterisation of OsDREB1F-overexpressing Arabidopsis showed that, besides activating the expression of COR genes which contain DRE/CRT element in their upstream promoter regions, the expression of rd29B and RAB18 genes were also activated, suggested that OsDREB1F may also participate in ABA-dependent pathway.

A bZIP transcription factor, OsABI5, is involved in rice fertility and stress tolerance.

The phytohormone abscisic acid (ABA) is involved in the adaptive stress response and regulates expression of many stress-responsive genes, including some transcriptional factors. A bZIP transcription factor, OsABI5, was isolated from the panicle of Oryza sativa L. Expression of the OsABI5 gene was induced by abscisic acid (ABA) and high salinity, and down-regulated by drought and cold (4 degrees C) in seedlings. The OsABI5 protein was localized in the nucleus and has trans-activation activity. The N-terminal of the protein is necessary for its activity. OsABI5 could bind to a G-box element and trans-activate reporter gene expression. Complementation analysis revealed that the expression of OsABI5 driven by the 35S promoter could rescue ABA-insensitivity of abi5-1 during seed germination and result in hypersensitivity to ABA. Over-expression of OsABI5 in rice conferred high sensitivity to salt stress. Repression of OsABI5 promoted stress tolerance and resulted in low fertility of rice. These results suggested that OsABI5 could regulate the adaptive stress response and plant fertility of rice as a transcription factor.

Characterization of alternative splicing products of bZIP transcription factors OsABI5.

Alternative splicing allows many gene products to alter their biological functions. A bZIP-type transcription factor, OsABI5, undergoes alternative splicing. Two OsABI5 splicing variants were identified, designated OsABI5-1, and OsABI5-2 and their different expression patterns in tissues were analyzed. Despite a completely identical functional domain, OsABI5-2 could specifically bind to G-box element, but OsABI5-1 could not; the transactivation activity of OsABI5-1 was higher than that of OsABI5-2; the interaction strength of OsABI5-2 and OsVP1 was stronger than that of OsABI5-1 and OsVP1; indicating a different function in the regulation of downstream target genes. Complementation tests and ABA (abscisic acid) hypersensitivity of Arabidopsis transgenic lines revealed the redundant function of OsABI5 splicing variants in ABA signaling. The interaction between OsABI5-1 and OsABI5-2 was also confirmed. These results suggest that OsABI5 variants may have overlapping and distinct functions to fine tune gene expression in ABA signaling as transcription factors together with OsVP1.