According to cancer-related microRNA (miRNA) expression microarray research available in public databases, miR-362 expression is elevated in gastric cancer. However, the expression and biological role of miR-362 in gastric progression remain unclear.
miR-362 expression levels in gastric cancer tissues and cell lines were determined using real-time PCR. The roles of miR-362, in promoting gastric cancer cell proliferation and apoptosis resistance, were assessed by different biological assays, such as colony assay, flow cytometry and TUNEL assay. The effect of miR-362 on NF-κB activation was investigated using the luciferase reporter assay, fluorescent immunostaining.
MiR-362 overexpression induced cell proliferation, colony formation, and resistance to cisplatin-induced apoptosis in BGC-823 and SGC-7901 gastric cancer cells. MiR-362 increased NF-κB activity and relative mRNA expression of NF-κB–regulated genes, and induced nuclear translocation of p65. Expression of the tumor suppressor CYLD was inhibited by miR-362 in gastric cancer cells; miR-362 levels were inversely correlated with CYLD expression in gastric cancer tissue. MiR-362 downregulated CYLD expression by binding its 3′ untranslated region. NF-κB activation was mechanistically associated with siRNA-mediated downregulation of CYLD. MiR-362 inhibitor reversed all the effects of miR-362.
The results suggest that miR-362 plays an important role in repressing the tumor suppressor CYLD and present a novel mechanism of miRNA-mediated NF-κB activation in gastric cancer.
miR-362; NF-κB; CYLD; Gastric cancer; Proliferation; Apoptosis
Stroke is a major neurovascular disorder threatening human life and health. Very limited clinical treatments are currently available for stroke patients. Stem cell transplantation has shown promising potential as a regenerative treatment after ischemic stroke. The present investigation explores a new concept of mobilizing endogenous stem cells/progenitor cells from the bone marrow using a parathyroid hormone (PTH) therapy after ischemic stroke in adult mice. PTH 1-34 (80 µg/kg, i.p.) was administered 1 hour after focal ischemia and then daily for 6 consecutive days. After 6 days of PTH treatment, there was a significant increase in bone marrow derived CD-34/Fetal liver kinase-1 (Flk-1) positive endothelial progenitor cells (EPCs) in the peripheral blood. PTH treatment significantly increased the expression of trophic/regenerative factors including VEGF, SDF-1, BDNF and Tie-1 in the brain peri-infarct region. Angiogenesis, assessed by co-labeled Glut-1 and BrdU vessels, was significantly increased in PTH-treated ischemic brain compared to vehicle controls. PTH treatment also promoted neuroblast migration from the subventricular zone (SVZ) and increased the number of newly formed neurons in the peri-infarct cortex. PTH-treated mice showed significantly better sensorimotor functional recovery compared to stroke controls. Our data suggests that PTH therapy improves endogenous repair mechanisms after ischemic stroke with functional benefits. Mobilizing endogenous bone marrow-derived stem cells/progenitor cells using PTH and other mobilizers appears an effective and feasible regenerative treatment after ischemic stroke.
Stem cell transplantation therapy has emerged as a promising regenerative medicine for ischemic stroke and other neurodegenerative disorders. However, many issues and problems remain to be resolved before successful clinical applications of the cell-based therapy. To this end, some recent investigations have sought to benefit from well-known mechanisms of ischemic/hypoxic preconditioning. Ischemic/hypoxic preconditioning activates endogenous defense mechanisms that show marked protective effects against multiple insults found in ischemic stroke and other acute attacks. As in many other cell types, a sub-lethal hypoxic exposure significantly increases the tolerance and regenerative properties of stem cells and progenitor cells. So far, a variety of preconditioning triggers have been tested on different stem cells and progenitor cells. Preconditioned stem cells and progenitors generally show much better cell survival, increased neuronal differentiation, enhanced paracrine effects leading to increased trophic support, and improved homing to the lesion site. Transplantation of preconditioned cells helps to suppress inflammatory factors and immune responses, and promote functional recovery. Although the preconditioning strategy in stem cell therapy is still an emerging research area, accumulating information from reports over the last few years already indicates it as an attractive, if not essential, prerequisite for transplanted cells. It is expected that stem cell preconditioning and its clinical applications will attract more attention in both the basic research field of preconditioning as well as in the field of stem cell translational research. This review summarizes the most important findings in this active research area, covering the preconditioning triggers, potential mechanisms, mediators, and functional benefits for stem cell transplant therapy.
Stem cell preconditioning; Stroke; Ischemia; Neurodegenerative disorder; Heart attack
Chronic kidney disease-mineral bone disorder (CKD-MBD) is a systemic syndrome characterized by imbalances in mineral homeostasis, renal osteodystrophy (ROD) and ectopic calcification. The mechanisms underlying this syndrome in individuals with chronic kidney disease (CKD) are not yet clear.
We examined the effect of normal phosphate (NP) or high phosphate (HP) feeding in the setting of CKD on bone pathology, serum biochemistry and vascular calcification in calcification-prone dilute brown non-agouti (DBA/2) mice.
In both NP and HP-fed CKD mice, elevated serum parathyroid hormone and alkaline phosphatase (ALP) levels were observed, but serum phosphorus levels were equivalent compared with sham controls. CKD mice on NP diet showed trabecular alterations in the long bone consistent with high–turnover ROD, including increased trabecular number with abundant osteoblasts and osteoclasts. Despite trabecular bone and serum biochemical changes, CKD/NP mice did not develop vascular calcification. In contrast, CKD/HP mice developed arterial medial calcification (AMC), more severe trabecular bone alterations and cortical bone abnormalities that included decreased cortical thickness and density, and increased cortical porosity. Cortical bone porosity and trabecular number strongly correlated with the degree of aortic calcification.
HP feeding was required to induce the full spectrum of CKD-MBD symptoms in CKD mice.
chronic kidney disease-mineral bone disorder; high-turnover renal osteodystrophy; phosphate; vascular calcification
The migration of gonadotropin-releasing hormone (GnRH) neurons from the olfactory placode to the preoptic area (POA) from embryonic day 13 is important for successful reproduction during adulthood. Whether maternal glucocorticoid exposure alters GnRH neuronal morphology and number in the offspring is unknown. This study determines the effect of maternal dexamethasone (DEX) exposure on enhanced green fluorescent protein (EGFP) driven by GnRH promoter neurons (TG-GnRH) in transgenic rats dual-labelled with GnRH immunofluorescence (IF-GnRH). The TG-GnRH neurons were examined in intact male and female rats at different postnatal ages, as a marker for GnRH promoter activity. Pregnant females were subcutaneously injected with DEX (0.1 mg/kg) or vehicle daily during gestation days 13–20 to examine the number of GnRH neurons in P0 male offspring. The total number of TG-GnRH neurons and TG-GnRH/IF-GnRH neuronal ratio increased from P0 and P5 stages to P47–52 stages, suggesting temporal regulation of GnRH promoter activity during postnatal development in intact rats. In DEX-treated P0 males, the number of IF-GnRH neurons decreased within the medial septum, organum vasculosom of the lamina terminalis (OVLT) and anterior hypothalamus. The percentage of TG-GnRH neurons with branched dendritic structures decreased in the OVLT of DEX-P0 males. These results suggest that maternal DEX exposure affects the number and dendritic development of early postnatal GnRH neurons in the OVLT/POA, which may lead to altered reproductive functions in adults.
Glucocorticoid; GnRH neuron; Dendrite; Preoptic area; Reproduction
The exposure of skin keratinocytes to Ultraviolet (UV) irradiation leads to Akt phosphorylation at Ser-473, which is important for the carcinogenic effects of excessive sun exposure. The present study investigated the underlying mechanism of Akt Ser-473 phosphorylation by UVB radiation.
We found that DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and mammalian target of rapamycin (mTOR) complex 2 (mTORC2) were both required for UVB-induced Akt Ser-473 phosphorylation in keratinocytes. Inhibition of DNA-PKcs activity via its inhibitor NU7026, a dominant-negative kinase-dead mutation, RNA interference (RNAi) or gene depletion led to the attenuation of UVB-induced Akt Ser-473 phosphorylation. Meanwhile, siRNA silencing or gene depletion of SIN1, a key component of mTORC2, abolished Akt Ser-473 phosphorylation by UVB. Significantly, we discovered that DNA-PKcs was associated with SIN1 in cytosol upon UVB radiation, and this complexation appeared required for Akt Ser-473 phosphorylation. Meanwhile, this DNA-PKcs-SIN1 complexation by UVB was dependent on epidermal growth factor receptor (EGFR) activation, and was disrupted by an EGFR inhibitor (AG1478) or by EGFR depletion. UVB-induced complexation between DNA-PKcs and mTORC2 components was also abolished by NU7026 and DNA-PKcs mutation. Finally, we found that both DNA-PKcs and SIN1 were associated with apoptosis resistance of UVB radiation, and inhibition of them by NU7026 or genetic depletion significantly enhanced UVB-induced cell death and apoptosis.
Taken together, these results strongly suggest that DNA-PKcs-mTORC2 association is required for UVB-induced Akt Ser-473 phosphorylation and cell survival, and might be important for tumor cell transformation.
UV irradiation; Akt Ser-473 phosphorylation; DNA-PKcs; SIN1; Skin care
Lysyl oxidase (LOX), a copper-dependent amine oxidase known to function both intracellularly and extracellularly, is implicated in promoting tumor progression and hypoxic metastasis in certain malignancies. Nonsmall cell lung cancer (NSCLC) is a highly aggressive cancer with poor prognosis worldwide. However, the role and molecular mechanism by which LOX involving in hypoxic NSCLC invasion and migration are poorly understood. This study explores the effect of LOX on invasion and migration of NSCLC cells under hypoxic conditions. Small interfering RNA (siRNA) targeting LOX was used to silence LOX expression of hypoxic NSCLC cells, SPCA1 and A549. Cellular invasive and migratory potentials were determined by matrigel invasion and migration assays. Expression of LOX, Src, Src activation (Tyr418 phosphorylation of Src), and Snail were evaluated by real-time PCR and western blot, respectively. The results showed that LOX mRNA and protein expression were upregulated under hypoxic conditions in NSCLC cells. Knockdown of LOX led to inhibition of hypoxia-induced invasion and migration. Phosphorylated Src (Tyr418) and Snail proteins were decreased along with LOX downregulation. Our data provide molecular evidences that LOX is mechanistically linked to increased invasion and migration of hypoxic NSCLC cells, and may serve as an antimetastasis target of human NSCLC.
hypoxia; invasion; lysyl oxidase; migration; nonsmall cell lung cancer; Snail; Src signaling pathway
Elevated fibroblast growth factor 23 (FGF23) is associated with cardiovascular disease in patients with chronic kidney disease. As a potential mediating mechanism, FGF23 induces left ventricular hypertrophy; however, its role in arterial calcification is less clear. In order to study this we quantified coronary artery and thoracic aorta calcium by computed tomography in 1501 patients from the Chronic Renal Insufficiency Cohort (CRIC) study within a median of 376 days (interquartile range 331 to 420 days) of baseline. Baseline plasma FGF23 was not associated with prevalence or severity of coronary artery calcium after multivariable adjustment. In contrast, higher serum phosphate levels were associated with prevalence and severity of coronary artery calcium, even after adjustment for FGF23. Neither FGF23 nor serum phosphate were consistently associated with thoracic aorta calcium. We could not detect mRNA expression of FGF23 or its co-receptor, klotho, in human or mouse vascular smooth muscle cells, or normal or calcified mouse aorta. Whereas elevated phosphate concentrations induced calcification in vitro, FGF23 had no effect on phosphate uptake or phosphate-induced calcification regardless of phosphate concentration or even in the presence of soluble klotho. Thus, in contrast to serum phosphate, FGF23 is not associated with arterial calcification and does not promote calcification experimentally. Hence, phosphate and FGF23 promote cardiovascular disease through distinct mechanisms.
phosphate; fibroblast growth factor 23; vascular calcification; vascular smooth muscle; chronic kidney disease
High-throughput, image-based screens of cellular responses to genetic or chemical perturbations generate huge numbers of cell images. Automated analysis is required to quantify and compare the effects of these perturbations. However, few of the current freely-available bioimage analysis software tools are optimized for efficient handling of these images. Even fewer of them are designed to transform the phenotypic features measured from these images into discriminative profiles that can reveal biologically meaningful associations among the tested perturbations.
We present a fast and user-friendly software platform called "cellXpress" to segment cells, measure quantitative features of cellular phenotypes, construct discriminative profiles, and visualize the resulting cell masks and feature values. We have also developed a suite of library functions to load the extracted features for further customizable analysis and visualization under the R computing environment. We systematically compared the processing speed, cell segmentation accuracy, and phenotypic-profile clustering performance of cellXpress to other existing bioimage analysis software packages or algorithms. We found that cellXpress outperforms these existing tools on three different bioimage datasets. We estimate that cellXpress could finish processing a genome-wide gene knockdown image dataset in less than a day on a modern personal desktop computer.
The cellXpress platform is designed to make fast and efficient high-throughput phenotypic profiling more accessible to the wider biological research community. The cellXpress installation packages for 64-bit Windows and Linux, user manual, installation guide, and datasets used in this analysis can be downloaded freely from http://www.cellXpress.org.
Honokiol is a poly-phenolic compound that exerts neuroprotective properties through a variety of mechanisms. It has therapeutic potential in anxiety, pain, cerebrovascular injury, epilepsy, and cognitive disorders including Alzheimer’s disease. It has been traditionally used in medical practices throughout much of Southeast Asia, but has now become more widely studied due to its pleiotropic effects. Most current research regarding this compound has focused on its chemotherapeutic properties. However, it has the potential to be an effective neuroprotective agent as well. This review summarizes what is currently known regarding the mechanisms involved in the neuroprotective and anesthetic effects of this compound and identifies potential areas for further research.
honokiol; neuroprotection; GABA; stroke; inflammatory pain; amyloid; magnolol; analgesia
Ischemic stroke is a leading cause of death and disability, but treatment options are severely limited. Cell therapy offers an attractive strategy for regenerating lost tissues and enhancing the endogenous healing process. In this study, we investigated the use of human embryonic stem cell-derived neural precursors as a cell therapy in a murine stroke model.
Neural precursors were derived from human embryonic stem cells by using a fully adherent SMAD inhibition protocol employing small molecules. The efficiency of neural induction and the ability of these cells to further differentiate into neurons were assessed by using immunocytochemistry. Whole-cell patch-clamp recording was used to demonstrate the electrophysiological activity of human embryonic stem cell-derived neurons. Neural precursors were transplanted into the core and penumbra regions of a focal ischemic stroke in the barrel cortex of mice. Animals received injections of bromodeoxyuridine to track regeneration. Neural differentiation of the transplanted cells and regenerative markers were measured by using immunohistochemistry. The adhesive removal test was used to determine functional improvement after stroke and intervention.
After 11 days of neural induction by using the small-molecule protocol, over 95% of human embryonic stem-derived cells expressed at least one neural marker. Further in vitro differentiation yielded cells that stained for mature neuronal markers and exhibited high-amplitude, repetitive action potentials in response to depolarization. Neuronal differentiation also occurred after transplantation into the ischemic cortex. A greater level of bromodeoxyuridine co-localization with neurons was observed in the penumbra region of animals receiving cell transplantation. Transplantation also improved sensory recovery in transplant animals over that in control animals.
Human embryonic stem cell-derived neural precursors derived by using a highly efficient small-molecule SMAD inhibition protocol can differentiate into electrophysiologically functional neurons in vitro. These cells also differentiate into neurons in vivo, enhance regenerative activities, and improve sensory recovery after ischemic stroke.
Human embryonic stem cell; Neural precursor; Electrophysiology; Stem cell; Cell therapy; Ischemic stroke; Neurogenesis; Small molecule
Background: Matrix metalloproteinase 10 (MMP10) plays an important role in ischemic stroke and has a close relationship with some stroke risk factors. The aim of this study was to investigate the relationship between two single nucleotide polymorphisms (SNP) in the exon regions of the MMP10 gene and atherothrombotic cerebral infarction risk. Methods: Five hundred and thirty-seven hospital-based patients who had suffered first atherothrombotic cerebral infarction and 580 unrelated healthy controls were enrolled. Demographic and clinical features of the subjects were recorded, and two polymorphisms, rs17435959 (G>C), rs17293607 (C>T) were chosen to be genotyped by real-time polymerase chain reaction-restriction TaqMan probes using the ABI 7300 TaqMan platform. Results: There were several clinical parameters, such as blood pressure, fasting blood glucose, total cholesterol, homocysteine, as well as carotid plaque and smoking, but not average age and sex ratios that showed significant differences between patients and control subjects. For rs17435959, there was no significant difference between the ischemic stroke group and the healthy control group in genotype frequency (OR=1.295, P=0.187, 95% CI (0.882-1.899)) or allele frequency (OR=1.267, P=0.202, 95% CI (0.881-1.823)). Moreover, in smoking, none smoking, having carotid plaque, no carotid plaque, male or female subtypes, there was significant difference between patients and control subjects in genotype frequencies or allele frequencies. The minor allele frequency of rs17293607 was 0.92%, prohibiting further study of this allele. Conclusions: These findings suggest that the rs17435959 SNP may not associated with atherothrombotic cerebral infarction risk. We also found that rs17293607 is not polymorphic in our study population.
Matrix metalloproteinase 10; polymorphism; genetic; genetic predisposition to disease; atherothrombotic cerebral infarction
Hypoxic preconditioning of stem cells and neural progenitor cells has been tested for promoting cell survival after transplantation. The present investigation examined the hypothesis that hypoxic preconditioning of bone marrow mesenchymal stem cells (BMSCs) could not only enhance their survival but also reinforce regenerative properties of these cells. BMSCs from eGFP engineered rats or pre-labeled with BrdU were pre-treated with normoxia (20% O2, N-BMSCs) or sublethal hypoxia (0.5% O2. H-BMSCs). The hypoxia exposure up-regulated HIF-1α and trophic/growth factors in BMSCs, including brain-derived neurotrophic factor (BDNF), glial cell-derived neurotrophic factor (GDNF), vascular endothelial growth factor (VEGF) and its receptor FIK-1, erythropoietin (EPO) and its receptor EPOR, stromal derived factor-1 (SDF-1) and its CXC chemokine receptor 4 (CXCR4). Meanwhile, many pro-inflammatory cytokines/chemokines were downregulated in H-BMSCs. N-BMSCs or H-BMSCs were intravenously injected into adult rats 24 hrs after 90-min middle cerebral artery occlusion. Comparing to N-BMSCs, transplantation of H-BMSCs showed greater effect of suppressing microglia activity in the brain. Significantly more NeuN-positive and Glut1-positive cells were seen in the ischemic core and peri-infarct regions of the animals received H-BMSC transplantation than that received N-BMSCs. Some NeuN-positive and Glut-1-positive cells showed eGFP or BrdU immunoflourescent reactivity, suggesting differentiation from exogenous BMSCs into neuronal and vascular endothelial cells. In Rota-rod test performed 15 days after stroke, animals received H-BMSCs showed better locomotion recovery compared with stroke control and N-BMSC groups. We suggest that hypoxic preconditioning of transplanted cells is an effective means of promoting their regenerative capability and therapeutic potential for the treatment of ischemic stroke.
hypoxic preconditioning; bone marrow mesenchymal stem cell; transplantation; angiogenesis; neurogenesis
Vascular calcification is common in chronic kidney disease, where cardiovascular mortality remains the leading cause of death. Patients with kidney disease are often prescribed vitamin D receptor agonists (VDRAs) that confer a survival benefit, but the underlying mechanisms remain unclear. Here we tested two VDRAs in a mouse chronic kidney disease model where dietary phosphate loading induced aortic medial calcification. Mice were given intraperitoneal calcitriol or paricalcitol three times per week for three weeks. These treatments were associated with half of the aortic calcification compared to no therapy, and there was no difference between the two agents. In the setting of a high phosphate diet, serum parathyroid hormone and calcium levels were not significantly altered by treatment. VDRA therapy was associated with increased serum and urine klotho levels, increased phosphaturia, correction of hyperphosphatemia, and lowering of serum fibroblast growth factor-23. There was no effect on elastin remodeling or inflammation, however, the expression of the anti-calcification factor, osteopontin, in aortic medial cells was increased. Paricalcitol upregulated osteopontin secretion from mouse vascular smooth muscle cells in culture. Thus, klotho and osteopontin were upregulated by VDRA therapy in chronic kidney disease, independent of changes in serum parathyroid hormone and calcium.
Vascular calcification; chronic kidney disease; vitamin D; klotho; osteopontin
Stroke is a leading cause of human death and disability in the adult population in the United States and around the world. While stroke treatment is limited, stem cell transplantation has emerged as a promising regenerative therapy to replace or repair damaged tissues and enhance functional recovery after stroke. Recently, the creation of induced pluripotent stem (iPS) cells through reprogramming of somatic cells has revolutionized cell therapy by providing an unlimited source of autologous cells for transplantation. In addition, the creation of vector-free and transgene-free human iPS (hiPS) cells provides a new generation of stem cells with a reduced risk of tumor formation that was associated with the random integration of viral vectors seen with previous techniques. However, the potential use of these cells in the treatment of ischemic stroke has not been explored. In the present investigation, we examined the neuronal differentiation of vector-free and transgene-free hiPS cells and the transplantation of hiPS cell-derived neural progenitor cells (hiPS-NPCs) in an ischemic stroke model in mice. Vector-free hiPS cells were maintained in feeder-free and serum-free conditions and differentiated into functional neurons in vitro using a newly developed differentiation protocol. Twenty eight days after transplantation in stroke mice, hiPS-NPCs showed mature neuronal markers in vivo. No tumor formation was seen up to 12 months after transplantation. Transplantation of hiPS-NPCs restored neurovascular coupling, increased trophic support and promoted behavioral recovery after stroke. These data suggest that using vector-free and transgene-free hiPS cells in stem cell therapy are safe and efficacious in enhancing recovery after focal ischemic stroke in mice.
16α-[18F]-fluoroestradiol ([18F]FES), a steroid-based positron emission tomography (PET) tracer, has emerged as a dependable tracer for the evaluation and management of estrogen receptor-positive (ER+) breast cancer patients. We have developed a fully automatic, one-pot procedure for the synthesis of [18F]FES using the Eckert & Ziegler (E & Z) radiomodular system. After [18F]fluorination, the intermediate was hydrolyzed with 2.0 M HCl twice and neutralized with sodium bicarbonate. After high-performance liquid chromatography (HPLC) purification, the decay-corrected radiochemical yield and purity of [18F]FES were 40 ± 5.0% (n = 12) and >97%, respectively. The product was stable up to 10 h. Total synthesis time including HPLC purification was 80 min. This new, fully automated rapid synthetic procedure provided high and reproducible yields of [18F]FES. Quality control (QC) tests showed that the [18F]FES produced by this method met all specifications for human injection.
Bone marrow-derived mesenchymal stem cells (BMSCs) have shown great promise for ischemic tissue repair. However, poor viability of transplanted BMSCs within ischemic tissues has limited their therapeutic potential. Apelin, an endogenous peptide, whose level is elevated following ischemia, has been shown to enhance survival of cardiomyocytes and neuronal cells during ischemia. We hypothesized that apelin-13 protects BMSCs from apoptotic death. In this paper we determined the potential mechanism of apelin-13 effects using cultured BMSCs from adult rats. Apoptosis was induced by the specific apoptotic insult serum deprivation (SD) for up to 36 hrs. Apoptotic cell death was measured using immunostaining and Western blotting in the presence and absence of apelin-13 (0.1 to 5.0 nM) co-applied during SD exposure. SD-induced apoptosis was significantly reduced by apelin-13 in a concentration-dependent manner. SD-induced mitochondrial depolarization, cytochrome c release, and caspase-3 activation were largely prevented by apelin-13. The apelin-13 anti-apoptotic effects were blocked by inhibiting the MAPK/ERK1/2 and PI3K/Akt signaling pathways. Taken together, our findings indicate that apelin-13 is a survival factor for BMSCs and its anti-apoptotic property may prove to be of therapeutic significance in terms of exploiting BMSC-based transplantation therapy.
Apelin-13; Bone marrow mesenchymal stem cells; Serum deprivation; Apoptosis
Neurons in the adult mammalian CNS do not spontaneously regenerate axons after injury due to CNS myelin and other inhibitory factors. Previous studies have showed that inhibition of the Rho-ROCK pathway promotes axonal outgrowth in primary neurons or in spinal cord injury models. Furthermore, RhoA inhibitor C3 transferase has a potential effect to induce neural differentiation in primary cultured neurons and cell lines. As stem cells and stem cell-derived neural progenitor cells have emerged as a regenerative medicine for stroke, Parkinson’s disease and other neurological disorders, strategies that can promote axonal outgrowth and neuronal differentiation appear to have promising benefits in the cell-based therapy. Currently, how changes in the Rho-ROCK pathway may affect the neurite outgrowth and neuronal differentiation of stem cells has been poorly understood. The present investigation examined the effects of RhoA inhibition on neurite outgrowth and neuronal differentiation of neural stem cells (NSCs) isolated from the subventricular zone (SVZ) of the mouse. Our results show that inhibition of RhoA leads to neurite outgrowth of NSCs not only on normal culture substrate, poly-D-lysine (PDL), but also on myelin substrate. Moreover, inhibition of RhoA improves neuronal differentiation of NSCs and up-regulates biomarkers of neuronal gene expression. These results support that the Rho signaling pathway plays an important role in neurite development and neuronal differentiation of NSCs.
Neural stem cells; Rho signaling pathway; neurite outgrowth; neuronal differentiation; myelin
Integrins mediate cell-cell and cell-extracellular matrix attachments. Integrins are signaling receptors because their cytoplasmic tails are docking sites for cytoskeletal and signaling proteins. Kindlins are a family of band 4.1-ezrin-radixin-moesin-containing intracellular proteins. Apart from regulating integrin ligand-binding affinity, recent evidence suggests that kindlins are involved in integrin outside-in signaling. Kindlin-3 is expressed in platelets, hematopoietic cells and endothelial cells. In humans, loss of kindlin-3 expression accounts for the rare autosomal disease leukocyte adhesion deficiency (LAD) type III that is characterized by bleeding disorders and defective recruitment of leukocytes into sites of infection. Studies have shown that the loss of kindlin-3 expression leads to poor ligand-binding properties of β1, β2 and β3 integrin subfamilies. The leukocyte-restricted β2 integrin subfamily comprises four members, namely αLβ2, αMβ2, αXβ2 and αDβ2. Integrin αMβ2 mediates leukocyte adhesion, phagocytosis, degranulation and it is involved in the maintenance of immune tolerance. Here we provide further evidence that kindlin-3 is required for integrin αMβ2-mediated cell adhesion and spreading using transfected K562 cells that expressed endogenous kindlin-3 but not β2 integrins. K562 stable cell line expressing si-RNA targeting kindlin-3, but not control-si-RNA, and transfected with constitutively activated integrin αMβ2N329S adhered and spread poorly on iC3b. We also show that kindlin-3 is required for the integrin αMβ2-Syk-Vav1 signaling axis that regulates Rac1 and Cdc42 activities. These findings reinforce a role for kindlin-3 in integrin outside-in signaling.
Pathological oxygen deprivation inhibits prolyl hydroxylase (PHD) activity and stimulates a protective cellular oxygen-sensing response in part through the stabilization and activation of the Hypoxia Inducible Factor (HIF) 1α transcription factor. The present investigation tested the therapeutic potential of enhanced activation of oxygen-sensing pathways by competitive pharmacologic PHD inhibition after stroke, hypothesizing that post-ischemic PHD inhibition would reduce neuronal cell death and require the activation of HIF-1α. The PHD inhibitor dimethyloxaloylglycine (DMOG, 100μM) reduced cell death by oxygen glucose deprivation (OGD), an in vitro model of ischemia, and the protection required HIF-1α. In vivo, DMOG (50mg/kg, i.p.) administered 30 or 60 min after distal occlusion of the middle cerebral artery (MCA) in mice enhanced the activation of HIF-1α protein, enhanced transcription of the HIF-regulated genes vascular endothelial growth factor, erythropoietin, endothelial nitric oxide synthase, and pyruvate dehydrogenase kinase-1, reduced ischemic infarct volume and activation of the pro-apoptotic caspase-3 protein, reduced behavioral deficits after stroke, and reduced the loss of local blood flow in the MCA territory after stroke. Inhibition of HIF-1α in vivo by Digoxin or Acriflavine abrogated the infarct sparing properties of DMOG. These data suggest that supplemental activation of oxygen-sensing pathways after stroke may provide a clinically applicable intervention for the promotion of neurovascular cell survival after ischemia.
Focal cerebral ischemia; hypoxia inducible factor; prolyl hydroxylase; preconditioning; postconditioning; dimethyloxaloylglycine
Heparanase is a heparan sulfate degrading endoglycosidase. Previous work has demonstrated that heparanase plays important roles in various biological processes including angiogenesis, wound healing and metastasis. However, the role of heparanase in the post-ischemic brain is not well defined. Transient focal cerebral ischemia in adult mice was induced by ligations of the right middle cerebral artery (MCA) and both common carotid arteries (CCAs). All mice were subjected to bromodeoxyuridine (BrdU) injection and sacrificed at different time points after stroke for immunohistochemical and Western blot analyses. Heparanase expression increased after ischemia in both cell-specific and time-dependent manners. Three to 7 days after stroke, levels of the 50-kD heparanase, basic fibroblast growth factor (FGF-2), and angiopoietin-2 (Ang-2) increased in the peri-infarct region. At early time points, heparanase expression was largely confined to proliferating vascular endothelial cells. At 14 days after ischemia, this expression had shifted to astrocytes in the same region. These data show that cerebral ischemia markedly increases heparanase levels in endothelial cells and then in astrocytes. The unique features of the heparanase upregulation imply that heparanase may play specific roles in the pathological and regenerative processes during the acute and sub-acute/chronic phase in the post-stroke brain.
Heparanase; Cerebral ischemia; Endothelial cells; Astrocytes; Angiogenesis; FGF-2; Angiopoietin-2
Cognitive change is prevalent in patients with amyotrophic lateral sclerosis (ALS), but still lack a widely accepted and sensitive screening method. In this study, we try to find a sensitive screening battery for detecting subtle cognitive deficits in patients with ALS.
Eighty consecutive ALS patients and 57 matched normal controls underwent the Mini-Mental Status Examination (MMSE), the verbal fluency test (VFT), the Stroop Color Word Interference Test (CWT), and the prospective memory (PM) tests, including event-based (EBPM) and time-based (TBPM).
The patients did not differ from the controls in the MMSE, the VFT and the CWT. By contrast, statistically significant differences were found in the PM tests (EBPM: P=0.043; TBPM: P<0.001). More interestingly, TBPM was more sensitive than EBPM in the early-phase patients.
Prefrontal lobar dysfunction does exist among ALS patients and may spread from the medial to the lateral region. The PM tests seem more sensitive in ALS patients with frontotemporal dysfunction than are the classical cognitive measures.
Bufalin is the primary component of the traditional Chinese herb “Chan Su”. Evidence suggests that this compound possesses potent anti-tumor activities, although the exact molecular mechanism(s) is unknown. Our previous study showed that bufalin inhibited growth of human osteosarcoma cell lines U2OS and U2OS/MTX300 in culture. Therefore, this study aims to further clarify the in vitro and in vivo anti-osteosarcoma effects of bufalin and its molecular mechanism of action. We found bufalin inhibited both methotrexate (MTX) sensitive and resistant human osteosarcoma cell growth and induced G2/M arrest and apoptosis. Using a comparative proteomics approach, 24 differentially expressed proteins following bufalin treatment were identified. In particular, the level of an anti-apoptotic protein, heat shock protein 27 (Hsp27), decreased remarkably. The down-regulation of Hsp27 and alterations of its partner signaling molecules (the decrease in p-Akt, nuclear NF-κB p65, and co-immunoprecipitated cytochrome c/Hsp27) were validated. Hsp27 over-expression protected against bufalin-induced apoptosis, reversed the dephosphorylation of Akt and preserved the level of nuclear NF-κB p65 and co-immunoprecipitated Hsp27/cytochrome c. Moreover, bufalin inhibited MTX-resistant osteosarcoma xenograft growth, and a down-regulation of Hsp27 in vivo was observed. Taken together, bufalin exerted potent anti-osteosarcoma effects in vitro and in vivo, even in MTX resistant osteosarcoma cells. The down-regulation of Hsp27 played a critical role in bufalin-induced apoptosis in osteosarcoma cells. Bufalin may have merit to be a potential chemotherapeutic agent for osteosarcoma, particularly in MTX-resistant groups.
Spinocerebellar ataxia type 6 (SCA6) is an inherited neurodegenerative disease caused by a polyglutamine (polyQ) expansion in the CaV2.1 voltage-gated calcium channel subunit (CACNA1A). There is currently no treatment for this debilitating disorder and thus a pressing need to develop preventative therapies. RNA interference (RNAi) has proven effective at halting disease progression in several models of spinocerebellar ataxia (SCA), including SCA types 1 and 3. However, in SCA6 and other dominantly inherited neurodegenerative disorders, RNAi-based strategies that selectively suppress expression of mutant alleles may be required. Using a CaV2.1 mini-gene reporter system, we found that pathogenic CAG expansions in CaV2.1 enhance splicing activity at the 3′end of the transcript, leading to a CAG repeat length-dependent increase in the levels of a polyQ-encoding CaV2.1 mRNA splice isoform and the resultant disease protein. Taking advantage of this molecular phenomenon, we developed a novel splice isoform-specific (SIS)-RNAi strategy that selectively targets the polyQ-encoding CaV2.1 splice variant. Selective suppression of transiently expressed and endogenous polyQ-encoding CaV2.1 splice variants was achieved in a variety of cell-based models including a human neuronal cell line, using a new artificial miRNA-like delivery system. Moreover, the efficacy of gene silencing correlated with effective intracellular recognition and processing of SIS-RNAi miRNA mimics. These results lend support to the preclinical development of SIS-RNAi as a potential therapy for SCA6 and other dominantly inherited diseases.