Homology-based cloning and expression analysis of Rf genes encoding PPR-containing proteins in tobacco

As a model plant, mechanisms of the cytoplasmic male sterility/restoration of fertility (CMS/Rf) system in tobacco are seldom studied. Using Rf gene sequences from other Solanaceae plants and the draft genome of Nicotiana benthamiana, degenerate primers were designed to amplify the cDNA pool of N. tomentosiformis. In total, six possible Rf sequences were identified, two of which contained base-deletion mutations. The other four were intact open reading frames, of which NtomPPR5 harbored a 3-pentatricopeptide repeat (PPR) motif deletion. Structure analysis revealed that they all encoded a PPR-containing protein with putative mitochondrial targeting signals at their N-terminus, and they all belong to the P subfamily. Phylogenetic analysis showed that all of the Rf-coding PPRs clustered together, and recent duplication events might have occurred in tobacco after the divergence of the species. Quantitative reverse transcription polymerase chain reaction analysis demonstrated that the NtomRfs were expressed in all tissues of N. tomentosiformis and (CMS) K326, although the expression levels varied with gene, organ, and developmental stage. Furthermore, the expression levels of Rf sequences in K326 were lower than those in CMS K326. The molecular basis of the CMS/Rf system in tobacco requires further investigation.

Leptin-mediated regulation of ICAM-1 is Rho/ROCK dependent and enhances gastric cancer cell migration

Background:

Our previous study indicates that leptin enhances gastric cancer (GC) invasion. However, the exact effect of leptin on GC metastasis and its underlying mechanism remain unclear. Intercellular adhesion molecule-1 (ICAM-1), a major molecule in stabilising cell–cell and cell–extracellular matrix interactions, is overexpressed and has crucial roles in tumour metastasis.

Methods:

Here, we investigated leptin and ICAM-1 expression in GC tissues. Furthermore, we characterised the influence of leptin on ICAM-1 expression in GC cells and elucidated the underlying mechanism.

Results:

Leptin and ICAM-1 were overexpressed in GC tissues, and a strong positive correlation was observed. They were also related with clinical stage or lymph node metastasis. Furthermore, leptin induced GC cell (AGS and MKN-45) migration by upregulating ICAM-1, and knockdown of ICAM-1 by small interference RNA (siRNA) blocked this process. Cell surface ICAM-1, as well as soluble ICAM-1 (sICAM-1), was also enhanced by leptin. Moreover, leptin increased ICAM-1 expression through Rho/ROCK pathway, which was attenuated by pharmacological inhibition of Rho (C3 transferase) or its downstream effector kinase Rho-associated protein kinase (ROCK) (Y-27632).

Conclusions:

Our findings indicate that leptin enhances GC cell migration by increasing ICAM-1 through Rho/ROCK pathway, which might provide new insight into the significance of leptin in GC.

Quercetin promotes proliferation and differentiation of oligodendrocyte precursor cells after oxygen/glucose deprivation-induced injury

The aim of this study was to investigate quercetin's (Qu) ability to promote proliferation and differentiation of oligodendrocyte precursor cells (OPCs) under oxygen/glucose deprivation (OGD)-induced injury in vitro. The results showed that after OGD, OPCs survival rate was significantly increased by Qu as measured by Cell Counting Kit-8. Furthermore, Qu treatment reduced apoptosis of OPCs surveyed by Hoechst 33258 nuclear staining. Qu at 9 and 27 μM promoted the proliferation of OPCs the most by Brdu and Olig2 immunocytochemical staining after OGD 3 days. Also, Qu treatment for 8 days after OGD, the differentiation of OPCs to oligodendrocyte was detected by immunofluorescence staining showing that O4, Olig2, and myelin basic protein (MBP) positive cells were significantly increased compared to control group. Additionally, the protein levels of Olig2 and MBP of OPCs were quantified using western blot and mRNA levels of Olig2 and Inhibitor of DNA binding 2 (Id2) were measured by RT-PCR. Western blot showed a significant increase in Olig2 and MBP expression levels compared with controls after OGD and Qu treatment with a linear does-response curve from 3 to 81 μM. After treatment with Qu compared to its control group, Olig2 mRNA level was significantly up-regulated, whereas Id2 mRNA level was down-regulated. In conclusion, Qu at 3-27 μM can promote the proliferation and differentiation of OPCs after OGD injury and may regulate the activity of Olig2 and Id2.

Quercetin improves hypoxia-ischemia induced cognitive deficits via promoting remyelination in neonatal rat

Myelination failure is associated with perinatal cerebral hypoxia-ischemia (PHI) induced brain injury in premature infants. How to efficiently promote remyelination is crucial for improving cognitive deficits caused by brain injury. Here, we demonstrated that quercetin (Que), a kind of flavonoids, significantly improved cognitive deficits and the behavior of PHI-rat in Morris water maze and open field tasks. After administration of Que to PHI-rat, the number of neogenetic Olig2⁺ oligodendrocyte progenitor cells (OPCs) was evidently increased in the subventricular zone. Additionally, in corpus callosum (CC), the expression of MBP (myelin basic protein) was increased, and the myelin sheaths reached normal level at 30 days with more compact while less damaged myelin sheaths and more mature oligodendrocytes (OLs) repopulating the CC compared with PHI groups. In a word, our findings indicated that Que could remarkably improve both cognition performance and myelination in the context of PHI-induced brain injury by promoting the proliferation of OPCs and strengthening survival of OLs in vivo.

Coffee, tea, and the risk of hip fracture: a meta-analysis

The present meta-analysis shows no clear association between coffee consumption and the risk of hip fractures. There was a nonlinear association between tea consumption and the risk of hip fracture. Compared to no tea consumption, drinking 1-4 cups of tea daily was associated with a lower risk of hip fracture.

INTRODUCTION

Prospective cohort and case-control studies have suggested that coffee and tea consumption may be associated with the risk of hip fracture; the results have, however, been inconsistent. We conducted a meta-analysis to assess the association between coffee and tea consumption and the risk of hip fracture.

METHODS

We performed systematic searches using MEDLINE, EMBASE, and OVID until February 20, 2013, without limits of language or publication year. Relative risks (RRs) with 95% confidence intervals (CI) were derived using random-effects models throughout all analyses. We conducted categorical, dose-response, heterogeneity, publication bias, and subgroup analyses.

RESULTS

Our study was based on 195,992 individuals with 9,958 cases of hip fractures from 14 studies, including six cohort and eight case-control studies. The pooled RRs of hip fractures for the highest vs. the lowest categories of coffee and tea consumption were 0.94 (95% CI 0.71-1.17) and 0.84 (95% CI 0.66-1.02), respectively. For the dose-response analysis, we found evidence of a nonlinear association between tea consumption and the risk of hip fracture (p(nonlinearity) < 0.01). Compared to no tea consumption, 1-4 cups of tea per day may reduce the risk of hip fracture by 28% (0.72; 95% CI 0.56-0.88 for 1-2 cups/day), 37% (0.63; 95% CI 0.32-0.94 for 2-3 cups/day), and 21% (0.79; 95% CI 0.62-0.96 for 3-4 cups/day).

CONCLUSIONS

We found no significant association between coffee consumption and the risk of hip fracture. A nonlinear association emerged between tea consumption and the risk of hip fracture; individuals drinking 1-4 cups of tea per day exhibited a lower risk of hip fractures than those who drank no tea. The association between 5 daily cups of tea, or more, and hip fracture risk should be investigated.

Metabolite differences in the lenticular nucleus in type 2 diabetes mellitus shown by proton MR spectroscopy

BACKGROUND AND PURPOSE

Previous studies by using proton MR spectroscopy found metabolite abnormalities in the cerebral cortex and white matter of patients with type 2 diabetes mellitus. The present study was undertaken to detect metabolite differences in the lenticular nuclei and thalamus in patients with T2DM.

MATERIALS AND METHODS

Twenty subjects with T2DM and 22 age-matched control subjects underwent single-voxel MR spectroscopy in the left and right lenticular nuclei and left and right thalami. NAA/Cr and Cho/Cr ratios were calculated. Brain lactic acid, fasting blood glucose, and glycosylated hemoglobin levels were also monitored.

RESULTS

The NAA/Cr ratio was lower in the left lenticular nuclei of subjects with T2DM (P = .007), whereas the Cho/Cr ratio was increased in both the and right lenticular nuclei (P = .001). The NAA/Cr ratio was negatively correlated with FBG in the left (r = -0.573, P = .008) and right nuclei (r = -0.564, P = .010). It was also negatively correlated to HbA1c in the left (r = -0.560, P = .010) and right (r = -0.453, P = .045) nuclei. The Cho/Cr ratio was positively correlated with these variables (P < .05). No significant differences in NAA/Cr or Cho/Cr ratios were observed in the thalamus of patients with T2DM. Lactic acid was not detected in any of the patients in the study.

CONCLUSIONS

The different metabolic statuses of the lenticular nuclei and thalamus suggest different effects of T2DM in each of these brain nuclei, with the lenticular nuclei being more vulnerable than the thalamus. The abnormal metabolic status was observed before lesions had appeared in these brain areas.

Enhanced gene transfer with multilayered polyplexes assembled with layer-by-layer technique

Successful gene therapy asks for multifunctional vectors which can not only protect DNA from degradation but also transfer it into nuclear and subsequently express the loaded gene. Here we reported a novel multilayered delivery system constructed with DNA, protamine (Pro) and polyethylenimine (PEI) via lay-by-layer (LbL) technique, which posed multifunctions. DNA was previously condensed into a compact core with Pro which also contained nuclear localisation signals (NLS) domains for nuclear transfer. Then additional DNA was deposited as the first layer onto the cationic core via the electrostatic attraction which would increase the loading dose of DNA. At last, PEI was absorbed as the outmost layer to achieve the endosomal escape. Therefore a quaternary polyplexes which offered high loading of DNA, nuclear transfer ability and endosomal escape capability was constructed with the LbL technique. The obtained quaternary polyplexes showed positive surface charge, spherical morphology, a relatively narrow particle size distribution and strong DNA protection capability. Compared with commercially available PEI/DNA complexes, the novel multifuctional vector exhibited not only lower cytotoxicity (P<0.05) but also higher transfection efficiency in HepG2 and HeLa cells (P<0.05) in vitro test.

Stepwise differentiation of human adipose-derived mesenchymal stem cells toward definitive endoderm and pancreatic progenitor cells by mimicking pancreatic development in vivo

Pancreatic progenitor (PP) cells are tissue-committed cells, which can differentiate into all kinds of pancreatic cells. They are potential candidates for regeneration of pancreatic tissue. However, it is unfeasible to acquire PP cells from pancreatic tissues and expand them in vitro. Generation of PP cells from adipose tissue-derived mesenchymal stem cells (AD-MSCs) would provide an unlimited source of PP cells. Here we developed a 2-step stepwise protocol, which induced AD-MSCs to generate FOXA2- or SOX17-positive definitive endoderm (DE) (5 days) and pancreatic and duodenal homeobox gene 1 (PDX1)-positive PP cells (4-6 days). By mimicking the developmental progress in embryonic development, we optimized the timing and combination of cytokines to activate the key signaling pathways during pancreatic development. We found that activating the Nodal/Activin signal with Activin A could induce differentiation of AD-MSCs toward DE, which could be further promoted by the Wnt signaling pathway activator Wnt3a. Besides, transient T (BRACHYURY)(+) mesendodermal cells were observed during formation of DE from AD-MSCs. Subsequently, the Wnt signaling pathway inhibitor Dkk1 along with retinoic acid/FGF2 (60 ng/mL) further induced AD-MSC-derived DE cells to differentiate into PDX1-positive PP cells. The derived PP cells were capable to form pancreatic endocrine or exocrine cells. In conclusion, we established a stepwise protocol that could derive DE and PP cells from AD-MSCs. It might provide an unlimited source of autologous PP cells for pancreatic diseases.

Mesenchymal stem cells play a potential role in regulating the establishment and maintenance of epithelial-mesenchymal transition in MCF7 human breast cancer cells by paracrine and induced autocrine TGF-β

Although the epithelial-mesenchymal transition (EMT) is a normal process that occurs during development, it is thought to be associated with cancer progression and metastasis. Emerging evidence links mesenchymal stem cells (MSCs) in the tumor microenvironment with the occurrence of EMT in cancer progression. In this study, the human breast cancer cell line MCF7 was co-cultured with human adipose-derived MSCs (hAD-MSCs) in a transwell system. Co-cultured cells were analyzed for changes in cellular morphology, EMT markers, protein expression and tumor characteristics. We found that co-cultured MCF7 cells underwent EMT and established a stable mesenchymal phenotype after prolonged co-culturing. Here, we demonstrate that paracrine transforming growth factor-β1 (TGF-β1) secreted by hAD-MSCs regulated the establishment of EMT in MCF7 cells by targeting the ZEB/miR-200 regulatory loop. The downregulation of paracrine TGF-β1 levels can inhibit and reverse the EMT progress by downregulating ZEB1/2 and upregulating miR-200b and miR-200c. The maintenance of a stable mesenchymal state by MCF7 cells required the establishment of autocrine TGF-β signaling to drive and sustain ZEB expression, which had been initiated by the prolonged co-culturing with hAD-MSCs. These results suggest that MSCs may promote breast cancer metastasis by stimulating and facilitating the EMT process.

Mesenchymal stem/stromal cells induce the generation of novel IL-10-dependent regulatory dendritic cells by SOCS3 activation

Suppression of immune response by mesenchymal stem/stromal cells (MSCs) is well documented. However, their regulatory effects on immune cells, especially regulatory dendritic cells, are not fully understood. We have identified a novel Sca-1(+)Lin(-)CD117(-) MSC population isolated from mouse embryonic fibroblasts (MEF) that suppressed lymphocyte proliferation in vitro. Moreover, the Sca-1(+)Lin(-)CD117(-) MEF-MSCs induced hematopoietic stem/progenitor cells to differentiate into novel regulatory dendritic cells (DCs) (Sca-1(+)Lin(-)CD117(-) MEF-MSC-induced DCs) when cocultured in the absence of exogenous cytokines. Small interfering RNA silencing showed that Sca-1(+)Lin(-)CD117(-) MEF-MSCs induced the generation of Sca-1(+)Lin(-)CD117(-) MEF-MSC-induced DCs via IL-10-activated SOCS3, whose expression was regulated by the JAK-STAT pathway. We observed a high degree of H3K4me3 modification mediated by MLL1 and a relatively low degree of H3K27me3 modification regulated by SUZ12 on the promoter of SOCS3 during SOCS3 activation. Importantly, infusion of Sca-1(+)CD117(-)Lin(-) MEF-MSCs suppressed the inflammatory response by increasing DCs with a regulatory phenotype. Thus, our results shed new light on the role of MSCs in modulating regulatory DC production and support the clinical application of MSCs to reduce the inflammatory response in numerous disease states.

Integrated thermophilic submerged aerobic membrane bioreactor and electrochemical oxidation for pulp and paper effluent treatment--towards system closure

A novel integrated thermophilic submerged aerobic membrane bioreactor (TSAMBR) and electrochemical oxidation (EO) technology was developed for thermomechanical pulping pressate treatment with the aim of system closure. The TSAMBR was able to achieve a chemical oxygen demand (COD) removal efficiency of 88.6 ± 1.9-92.3 ± 0.7% under the organic loading rate of 2.76 ± 0.13-3.98 ± 0.23 kg COD/(m(3) d). An optimal hydraulic retention time (HRT) of 1.1 ± 0.1d was identified for COD removal. Cake formation was identified as the dominant mechanism of membrane fouling. The EO of the TSAMBR permeate was performed using a Ti/SnO(2)-Sb(2)O(5)-IrO(2) electrode. After 6-h EO, a complete decolourization was achieved and the COD removal efficiency was increased to 96.2 ± 1.2-98.2 ± 0.3%. The high-quality effluent produced by the TSAMBR-EO system can be reused as process water for system closure in pulp and paper mill.

MicroRNA-100 regulates osteogenic differentiation of human adipose-derived mesenchymal stem cells by targeting BMPR2

Elucidation of the molecular mechanisms governing human adipose-derived mesenchymal stem cells (hASCs) osteogenic differentiation is of great importance for improving the treatment of bone-related diseases. In this study, we examined the role of microRNA (miR)-100 on the osteogenesis of hASCs. Overexpression of miR-100 inhibited osteogenic differentiation of hASCs in vitro, whereas downregulation of miR-100 enhanced the process. Target prediction analysis and dual luciferase report assay confirmed that bone morphogenetic protein receptor type II (BMPR2) was a direct target of miR-100. Furthermore, knockdown of BMPR2 by RNA interference inhibited osteogenic differentiation of hASCs, similar as the effect of upregulation miR-100. Taken together, our findings imply that miR-100 plays a negative role in osteogenic differentiation and might act through targeting BMPR2.

Mesenchymal stem cells inhibit Th17 cell differentiation by IL-10 secretion

Recent findings indicate that mesenchymal stem cells (MSCs) may act as a regulator of Th17 cell differentiation, however, the underlying mechanism is still under debate. To investigate the underlying mechanisms of MSCs' regulatory effect, mouse bone marrow-derived MSCs were cocultured with mouse CD4(+)CD25(low)CD44(low)CD62L(high) T cells in vitro, and the proportion of induced Th17 cells, cytokines secretion, and transcription factors expression were examined by flow cytometry, enzyme-linked immunosorbent assay, quantitative reverse transcription polymerase chain reaction, and Western blotting. For the first time, our results showed that bone marrow-derived MSCs were able to inhibit Th17 cell differentiation via interleukin (IL)-10 secretion as the Th17 cell proportion was significantly regained when IL-10 was neutralized, or expression of IL-10 by bone marrow-derived MSCs was downregulated by RNA interference technique. Furthermore, IL-10 may suppress expression of Rorγt, the key transcription factor for Th17 cells, both by activating suppressor of cytokine signaling 3 through signal transducers and activators of transcription 5 phosphorylation, and decreasing signal transducers and activators of transcription 3 binding, which is at the promoter of Rorγt. Thus, our results demonstrate the inhibitory effect of MSCs on Th17 cells differentiation, and suggest increased IL-10 secretion might be the key factor.

Differential expression of microRNAs during allograft rejection

MicrorRNA are small noncoding RNA molecules that regulate the posttranscriptional expression of target genes. In addition to being involved in many biologic processes, microRNAs are important regulators in innate and adaptive immune responses. Distinct sets of expressed microRNAs are found in different cell types and tissues and aberrant expression of microRNAs is associated with many disease states. MicroRNA expression was examined in a model of heterotopic heart transplantation by microarray analyses and a unique profile was detected in rejecting allogeneic transplants (BALB/c → C57BL/6) as compared to syngeneic transplants (C57BL/6 → C57BL/6). The microRNA miR-182 was significantly increased in rejecting cardiac allografts and in mononuclear cells that infiltrate the grafts. Forkhead box (FOX) proteins are a family of important transcription factors and FOXO1 is a target of miR-182. As miR-182 increases after transplant, there is a concomitant posttranscriptional decrease in FOXO1 expression in heart allografts that is localized to both the cardiomyocytes and CD3(+) T cells. The microRNA miR-182 is significantly increased in both peripheral blood mononuclear cells and plasma during graft rejection suggesting potential as a biomarker of graft status. Our results identify microRNAs that may regulate alloimmune responses and graft outcomes.

Clinical applications of mesenchymal stem cells

Mesenchymal stem cells (MSC) have generated a great amount of enthusiasm over the past decade as a novel therapeutic paradigm for a variety of diseases. Currently, MSC based clinical trials have been conducted for at least 12 kinds of pathological conditions, with many completed trials demonstrating the safety and efficacy. This review provides an overview of the recent clinical findings related to MSC therapeutic effects. Roles of MSCs in clinical trials conducted to treat graft-versus-host-disease (GVHD) and cardiovascular diseases are highlighted. Clinical application of MSC are mainly attributed to their important four biological properties- the ability to home to sites of inflammation following tissue injury when injected intravenously; to differentiate into various cell types; to secrete multiple bioactive molecules capable of stimulating recovery of injured cells and inhibiting inflammation and to perform immunomodulatory functions. Here, we will discuss these four properties. Moreover, the issues surrounding clinical grade MSCs and principles for MSC therapeutic approaches are also addressed on the transition of MSCs therapy from bench side to bedside.