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
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.
Deubiquitinating enzymes (DUBs) are proteases that control the post-translational modification of proteins by ubiquitin and in turn regulate diverse cellular pathways. Despite a growing understanding of DUB biology at the structural and molecular level, little is known about the physiological importance of most DUBs. Here, we systematically identify DUBs encoded by the genome of Drosophila melanogaster and examine their physiological importance in vivo. Through domain analyses we uncovered 41 Drosophila DUBs, most of which have human orthologues. Systematic knockdown of the vast majority of DUBs throughout the fly or in specific cell types had dramatic consequences for Drosophila development, adult motility or longevity. Specific DUB subclasses proved to be particularly necessary during development, while others were important in adults. Several DUBs were indispensable in neurons or glial cells during developmental stages; knockdown of others perturbed the homeostasis of ubiquitinated proteins in adult flies, or had adverse effects on wing positioning as a result of neuronal requirements. We demonstrate the physiological significance of the DUB family of enzymes in intact animals, find that there is little functional redundancy among members of this family of proteases, and provide insight for future investigations to understand DUB biology at the molecular, cellular and organismal levels.
Previous studies indicated that type 2 diabetes mellitus (T2DM) might be associated with the risk of cancer. The aim of this study was to investigate the association between T2DM and the risk of developing common cancers in a Chinese population.
A population-based retrospective cohort study was carried out in the Nan-Hu district of Jiaxing city, Zhejiang province, China. The incidence of cancer cases among type 2 diabetic patients were identified through record-linkage of the Diabetic Surveillance and Registry Database with the Cancer Database from January 2002 to June 2008. The standardized incidence ratio (SIR) and 95% confidence interval (CI) were estimated for the risk of cancer among the patients with type 2 diabetes.
The overall incidence of cancer was 1083.6 per 105 subjects in male T2DM patients and 870.2 per 105 in females. Increased risk of developing cancer was found in both male and female T2DM patients with an SIR of 1.331 (95% CI = 1.143-1.518) and 1.737 (1.478-1.997), respectively. As for cancer subtypes, both male and female T2DM patients had a significantly increased risk of pancreatic cancer with the SIRs of 2.973 (1.73-4.21) and 2.687 (1.445-3.928), respectively. Elevated risk of liver and kidney cancers was only found in male T2DM patients with SIRs of 1.538 (1.005-2.072) and 4.091 (1.418-6.764), respectively. Increased risks of developing breast cancer [2.209 (1.487-2.93)] and leukemia SIR: [4.167 (1.584- 6.749) ] were found in female patients.
These findings indicated that patients with T2DM have an increased risk of developing cancer. Additional cancer screening should be employed in the management of patients with T2DM.
Voltage-gated K+ channels are key regulators of neuronal excitability, playing major roles in setting resting membrane potential, repolarizing the cell membrane after action potentials and affecting transmitter release. The M-type channel or M-channel is a unique voltage- and ligand-regulated K+ channel. It is composed of the molecular counterparts KCNQ2 and KCNQ3 (also named Kv7.2 and Kv7.3) channels and expressed in the soma and dendrites of neurons. The present investigation examined the hypothesis that KCNQ2/3 channels played a regulatory role in neuronal differentiation and maturation. In cultured mouse embryonic stem (ES) cells undergoing neuronal differentiation and primary embryonic (E15-17) hippocampal cultures, KCNQ2 and KCNQ3 channels and underlying M-currents were identified. Blocking of KCNQ channels in these cells for 5 days using the specific channel blocker XE991 (10 μM) or linopirdine (30 μM) significantly decreased synaptophysin and syntaxin expression without affecting cell viability. Chronic KCNQ2/3 channel block reduced the expression of vesicular GABA transporter (v-GAT), but not vesicular glutamate transporter (v-GluT). Enhanced ERK1/2 phosphorylation was observed in XE991- and linopirdine-treated neural progenitor cells. In electrophysiological recordings, cells undergoing chronic block of KCNQ2/3 channels showed normal amplitude of mPSCs while the frequency of mPSCs was reduced. On the other hand, KCNQ channel opener N-Ethylmaleimide (NEM, 2 μM) increased mPSC frequency. Fluorescent imaging using fluorescent styryl-dye FM4-64 revealed that chronic blockade of KCNQ2/3 channels decreased endocytosis but facilitated exocytosis. These data indicate that KCNQ2/3 channels participate in regulation of neuronal differentiation and show a tonic regulation on pre-synaptic transmitter release and recycling in developing neuronal cells.
M-current; synaptogenesis; Neuronal differentiation; Mouse ES cells; Hippocampal neurons; KCNQ channels; ERK1/2
Paroxysmal Kinesigenic Dyskinesia with Infantile Convulsions (PKD/IC) is an episodic movement disorder with autosomal dominant inheritance and high penetrance, but the causative gene is unknown. We have now identified four truncating mutations involving the PRRT2 gene in the vast majority (24/25) of well characterized families with PKD/IC. PRRT2 truncating mutations were also detected in 28 of 78 additional families. The PRRT2 gene encodes a proline-rich transmembrane protein of unknown function that has been reported to interact with the t-SNARE, SNAP25. PRRT2 localizes to axons but not to dendritic processes in primary neuronal culture and mutants associated with PKD/IC lead to dramatically reduced PRRT2 protein levels leading ultimately to neuronal hyperexcitability that manifests in vivo as PKD/IC.
The ε4 allele of apolipoprotein E (APOE) is currently the major genetic risk factor identified for Alzheimer’s disease (AD). Previous in vivo data from our laboratory has demonstrated that amyloid-β (Aβ) is rapidly removed from the plasma by the liver and kidney and that the rate of its clearance is affected by ApoE in C57BL/6J and APOE−/− mice. To expand upon these findings, we assessed the peripheral clearance of human synthetic Aβ42 in APOE ε2, ε3, and ε4 knock-in and APOE knock-out mice injected with lipidated recombinant apoE2, E3, and E4 protein. Our results show that APOE does influence the rate at which the mice are able to clear Aβ42 from their bloodstream. Both APOE ε4 mice and APOE knock-out mice treated with lipidated recombinant apoE4 demonstrated increased retention of plasma Aβ42 over time compared to APOE ε2/APOE knock-out rE2 and APOE ε3/APOE knock-out rE3 mice. These findings suggest that the peripheral clearance of Aβ42 is significantly altered by APOE genotype. Given that APOE ε4 is a risk factor for AD, then these novel findings provide some insight into the role of ApoE isoforms on the peripheral clearance of Aβ which may impact on clearance from the brain.
Alzheimer’s disease; amyloid-β; APOE genotype; peripheral sink hypothesis
Elevated serum phosphate has clinically been associated with vascular stiffness and cardiovascular mortality. Mechanistic studies over the past decade looking at phosphate’s local effects on the vessel wall have lent insight into various pathways that culminate in vascular calcification.Smooth muscle cell phenotype change and apoptosis play prominent roles. The sodium-phosphate cotransporter PiT-1 is required for the osteochondrogenic differentiation of smooth muscle cellsin vitro. Less is known about phosphate-driven valve interstitial cell calcification and elastin degradation.In this paper, we review the current knowledge about phosphate-induced changes in the vascular wall.
Vascular calcification; phosphate; chronic kidney disease; smooth muscle cell; elastin degradation
Nanoparticles have an enormous potential for development in biomedical applications, such as gene or drug delivery. We developed and characterized aminopropyltriethoxysilane-functionalized silicon dioxide nanoparticles (APTES-SiNPs) for gene therapy. Lipofectamine® 2000, a commonly used agent, served as a contrast. We showed that APTES-SiNPs had a gene transfection efficiency almost equal to that of Lipofectamine 2000, but with lower cytotoxicity. Thus, these novel APTES-SiNPs can achieve highly efficient transfection of plasmid DNA, and to some extent reduce cytotoxicity, which might overcome the critical drawbacks in vivo of conventional carriers, such as viral vectors, organic polymers, and liposomes, and seem to be a promising nonviral gene therapy vector.
aminopropyltriethoxysilane; silicon dioxide nanoparticles; Lipofectamine® 2000; gene therapy vector; nanomedicine
Compound targeting histone deacetylase (HDAC) represents a new era in molecular cancer therapeutics. However, effective HDAC inhibitors for the treatment of solid tumors remain to be developed.
Here, we propose a novel HDAC inhibitor, N-Hydroxy-4-(4-phenylbutyryl-amino) benzamide (HTPB), as a potential chemotherapeutic drug for solid tumors. The HDAC inhibition of HTPB was confirmed using HDAC activity assay. The antiproliferative and anti-migratory mechanisms of HTPB were investigated by cell proliferation, flow cytometry, DNA ladder, caspase activity, Rho activity, F-actin polymerization, and gelatin-zymography for matrix metalloproteinases (MMPs). Mice with tumor xenograft and experimental metastasis model were used to evaluate effects on tumor growth and metastasis. Our results indicated that HTPB was a pan-HDAC inhibitor in suppressing cell viability specifically of lung cancer cells but not of the normal lung cells. Upon HTPB treatment, cell cycle arrest was induced and subsequently led to mitochondria-mediated apoptosis. HTPB disrupted F-actin dynamics via downregulating RhoA activity. Moreover, HTPB inhibited activity of MMP2 and MMP9, reduced integrin-β1/focal adhesion complex formation and decreased pericellular poly-fibronectin assemblies. Finally, intraperitoneal injection or oral administration of HTPB efficiently inhibited A549 xenograft tumor growth in vivo without side effects. HTPB delayed lung metastasis of 4T1 mouse breast cancer cells. Acetylation of histone and non-histone proteins, induction of apoptotic-related proteins and de-phosphorylation of focal adhesion kinase were confirmed in treated mice.
These results suggested that intrinsic apoptotic pathway may involve in anti-tumor growth effects of HTPB in lung cancer cells. HTPB significantly suppresses tumor metastasis partly through inhibition of integrin-β1/FAK/MMP/RhoA/F-actin pathways. We have provided convincing preclinical evidence that HTPB is a potent HDAC targeted inhibitor and is thus a promising candidate for lung cancer chemotherapy.
dl-3-n-Butylphthalide (NBP) has shown cytoprotective effects in animal models of stroke and has passed clinical trails as a therapeutic drug for stroke in China. Hence, as a potential clinical treatment for stroke, understanding the mechanism(s) of action of NBP is essential. This investigation aimed to delineate the cellular and molecular mechanism of NBP protection in neuronal cultures and in the ischemic brain. NBP (10 M) attenuated serum deprivation-induced neuronal apoptosis and the production of reactive oxygen species (ROS) in cortical neuronal cultures. Adult male 129 S2/sv mice were subjected to permanent occlusion of the middle cerebral artery (MCA). NBP (100 mg/kg, i.p.) administrated 2 hrs before or 1 hr after ischemia reduced ischemia-induced infarct formation, attenuated caspase-3 and caspase-9 activation in the ischemic brain. TUNEL-positive cells and mitochondrial release of cytochrome c and apoptosis-inducing-factor (AIF) in the penumbra region were reduced by NBP. The pro-apoptotic signaling mediated by phospho-JNK and p38 expression was down-regulated by NBP treatment in vitro and in vivo. It is suggested that NBP protects against ischemic damage via multiple mechanisms including mitochondria associated caspase-dependent and -independent apoptotic pathways. Previous and current studies and recent clinical trials encourage exploration of NBP as a neuroprotective drug for the treatment of ischemic stroke.
dl-3-n-butylphthalide; Ischemic stroke; Apoptosis; Caspase; AIF; Cytochrome C; Mitochondria; MAP kinase
Millennium Development Goal 4 calls for a reduction in the under-five mortality rate by two-thirds between 1990 and 2015, which corresponds to an annual rate of decline of 4.4%. The United Nations Inter-Agency Group for Child Mortality Estimation estimates under-five mortality in every country to measure progress. For the majority of countries, the estimates within a country are based on the assumption of a piece-wise constant rate of decline.
Methods and Findings
This paper proposes an alternative method to estimate under-five mortality, such that the underlying rate of change is allowed to vary smoothly over time using a time series model. Information about the average rate of decline and changes therein is exchanged between countries using a Bayesian hierarchical model. Cross-validation exercises suggest that the proposed model provides credible bounds for the under-five mortality rate that are reasonably well calibrated during the observation period. The alternative estimates suggest smoother trends in under-five mortality and give new insights into changes in the rate of decline within countries.
The proposed model offers an alternative modeling approach for obtaining estimates of under-five mortality which removes the restriction of a piece-wise linear rate of decline and introduces hierarchy to exchange information between countries. The newly proposed estimates of the rate of decline in under-5 mortality and the uncertainty assessments would help to monitor progress towards Millennium Development Goal 4.