Chemoprevention by the use of naturally occurring substances is becoming a promising strategy to prevent cancer. In this study, the effects of isoobtusilactone A, a novel constituent isolated from ...the leaves of
Cinnamomum kotoense, on the proliferation of human hepatoma Hep G2 cells were studied. Under our experimental conditions, isoobtusilactone A was found to elicit a concentration-dependent growth impediment (IC
50
=
37.5
μM). The demise of these cells induced by isoobtusilactone A was apoptotic in nature, exhibiting a concentration-dependent increase in sub-G
1 fraction and DNA fragmentation. Subcellular fractionation analysis further revealed that Bax translocation to mitochondria resulted in a rapid release of cytochrome
c, followed by activation of caspase 3 and PARP cleavage, and finally cell death. Isoobtusilactone A-treated cells also displayed transient increase of ROS during the earlier stage of the experiment, followed by the disruption of mitochondrial transmembrane potential (Δ
Ψ
m). The presence of a ROS scavenger (
N-acetyl-
l-cysteine) and an inhibitor of NADPH oxidase (diphenyleneiodonium chloride) blocked ROS production and the subsequent apoptotic cell death. In addition, in order to investigate the acute toxicity of isoobtusilactone A, groups of 5–6-week old Sprague–Dawley rats were subjected to oral administration of 350, or 700
mg/kg
bw isoobtusilactone A four times each week for two weeks. There was no significant difference between control animals and treated animals with respect to the body weight gain, the body weight ratio of liver, spleen and kidney, haematological and clinical chemistry parameters. Taken together, our data suggest that ROS generated through the activation of NADPH oxidase plays an essential role in apoptosis induced by isoobtusilactone A, and the dosages of isoobtusilactone A tested in this study did not cause animal toxicity.
Abstract Objective Essential tremor (ET) is an involuntary postural oscillation. It is unclear to which extent motor cortical activity in preparation of volitional movement is abnormal in ET. We ...measured the Bereitschaftspotential (BP) to address this question. Methods Given the known influence of the cerebello-dentato-thalamo-cortical projection in the generation of the BP, patients were divided into two groups, defined by purely postural tremor (ETPT ) or additional presence of intention tremor (ETIT ) and compared to healthy controls. BP was recorded during self-paced rapid wrist extension movements. Results The late BP (500–0 ms before movement onset) was increased over the mid-frontal area in ETPT , whereas it was reduced over the mid-parietal area in ETIT when compared to healthy controls. In addition, the late BP was reduced over a widespread centro-parietal area in ETIT compared to ETPT. Conclusions Findings suggest that presence vs. absence of cerebellar signs (intention tremor) in ET results in differential affection of volitional preparatory motor cortical activity. The BP increase in ETPT may indicate compensatory activity, whereas the widespread centro-parietal BP reduction in ETIT suggests dysfunction of the cerebello-dentato-thalamo-cortical projection. Significance Reduction of the late BP amplitude may serve as a surrogate marker for dysfunction of the cerebello-dentato-thalamo-cortical projection in ET.
Reports elsewhere demonstrated that Epimedin C, a constituent isolated from the leaves of Epimedium sagittatum, possessed anti-tumor activity. However, its mechanism of action remains unresolved. ...Using SK-Hep-1 cells, a poorly-differentiated hepatoma subline, as an experimental model, we present evidence here that the anti-tumor activity of Epimedin C may involve cell cycle blockage. Immunoblotting analyses demonstrated that Epimedin C caused a decreased expression of hyperphosphorylated retinoblastoma (Rb) protein, cyclin D1, c-Myc, and c-Fos. In parallel, we measured the kinase activities and found that CDK2 and CDK4 were suppressed with commensurate increased levels of CDK inhibitors, p21(Cip1) and p27(Kip1). These data suggested that Epimedin C arrested the proliferation of these cells at G0/G1 phase through inhibition of CDK2 and CDK4 activities via an increased induction of p21(Cip1) and p27(Kip1). Alternatively, we investigated whether the anti-proliferative effect of Epimedin C on these cells might involve MAP kinase cascade. Using western blotting technique, we demonstrated that Epimedin C also selectively decreased ERK1/2 phosphorylation. Among the downstream effectors of ERK examined, we found that Epimedin C selectively decreased the expression of c-Fos, but not c-Jun. By EMSA assay, we further demonstrated that decreased c-Fos resulted in the downregulation of AP-1/DNA binding activity. Taken together, the molecular mechanisms of anti-tumor activity of Epimedin C may be proceeded by the combined effects of the cell cycle blockage via either the inhibition of CDK2 and CDK4 activities, with commensurate increase in their inhibitors, p21(Cip1) and p27(Kip1) or negatively modulates the ERK/c-Fos/AP-1 signaling pathway.
Resveratrol butyrate esters (RBEs), which are novel resveratrol-synthesized derivatives, exhibit increased biological activity. This study elucidated the effect of RBEs on fat metabolism and their ...anti-obesity characteristics. Their molecular mechanism was investigated in the 3T3-L1 murine preadipocyte cells and adipocytes. RBE doses of < 2 μM did not induce a significant change in the viability of 3T3-L1 adipocytes. After RBEs treatment, intracellular lipid droplet accumulation in 3T3-L1 adipocytes was stimulated by methylisobutylxanthine, dexamethasone, and insulin-containing medium. However, a significant dose-dependent reduction in intracellular lipid levels was observed. The mRNA levels of two adipogenic transcription factors (peroxisome proliferator-activated receptor PPAR and CCAAT/enhancer-binding proteins C/EBP) and lipogenic proteins (fatty acid-binding protein 4 FABP4 and fatty acid synthase FAS) were significantly attenuated by RBE treatment in both MDI-stimulated and differentiated 3T3-L1 adipocytes. Moreover, the phosphorylation level of adenosine monophosphate-activated protein kinase (AMPK) also dramatically increased in the MDI + RBE-treated group compared to that in the MDI + vehicle-treated group. Collectively, our study provides strong evidence that RBEs inhibit adipogenesis by regulating adipogenic protein expression and increasing the p-AMPK/AMPK ratio. Future studies will be conducted on animal models to validate the application of RBEs as a functional food ingredient in improving human health.
Abstract Objective Movement-related cortical potentials (MRCP; nomenclature of MRCP components according to Shibasaki and Hallett (Shibasaki H, Hallett M. What is the Bereitschaftspotential? Clin ...Neurophysiol 2006;117:2341–56) were studied in patients with Machado–Joseph disease (MJD) to elucidate the pathophysiology of voluntary movement. Methods We studied nine genetically proven MJD patients and eight age-matched healthy subjects. Multi-channel electroencephalogram (EEG) recordings were obtained during self-paced fast extensions of the wrist. EEG epochs were time-locked to electromyography (EMG) onset or offset of the voluntary EMG burst and averaged. Results In the MJD patients, the early Bereitschaftspotential (early BP, −1500 to −500 ms) was not affected but the late BP was reduced over the central midline area and contralaterally to the movement side. The amplitude of the fpMP, a post-movement MRCP component, was also reduced. In addition, the offset cortical potential in the first 500 ms after EMG offset (Moff + 500) was attenuated bilaterally over a wide cortical area. Conclusions Findings suggest that cortical activations associated with the initiation and termination of a voluntary movement are impaired in MJD patients. Significance Abnormalities of pre- and post-movement MRCP components provide researchers with pathophysiological insight into voluntary motor dysfunction in MJD.
Background
Alzheimer’s disease (AD) is characterized by progressive decline of memory and cognitive functions. Accumulation of hyperphosphorylated tau is a pathological hallmark of AD and also plays ...a pathogenic role in disease progression. Proteolysis Targeting Chimera (PROTAC) technology enables the selective removal of a target protein by cellular ubiquitin‐proteasome system. Here we describe the characterization of tau PROTAC degrader developed at APRINOIA as a novel disease modifying treatment.
Methods
Tau degrader was synthesized by linking a proprietary tau binder from Aprinoia tau PET tracer program with a ligand of E3 ligase. The PROTAC mediated tau degradation was first evaluated in HEK293 cells expressing P301L tau, which develops tau oligomer and aggregates upon incubation with “tau seeds” from brain lysates of rTg4510 mice. The reduction of tau aggregates was measured using a HTRF based immunoassay. A similar seeding induced tau aggregation assay was established in primary neurons to confirm the degrader activity. Efficacy was further evaluated in rTg4510 mice following treatment with IV injection.
Results
PROTAC tau degrader reduced tau oligomer/aggregates in cellular models as well as in therTg4510 mice. Preliminary data suggests degrader is more effective in degradation of soluble tau oligomers in early stage of pathological tau development.
Conclusion
Tau PROTAC degrader generated from proprietary tau warhead can selectively decrease the oligomer/aggregated tau in both in vitro and in vivo models. Current effort is focused on optimization of ADME properties of tau degrader as a promising therapy for AD primary tauopathies.
Abstract We report the clinical features and dopamine transporter 2-2-3-(4-chlorophenyl)-8-methyl-8-azabicyclo3.2.1oct-2-ylmethyl(2-mercaptoethyl)aminoethylaminoethanethiolato(3-)- N 2, N 20, S 2, S ...20oxo-1 R -(exo-exo)-99mTc technetium(99mTcTRODAT-1) image finding in an 86-year-old woman with akinetic mutism due to infarction of bilateral anterior cerebral arterial territories. TRODAT-1 is a cocaine analogue that can be labeled with technetium-99m and bound to the dopamine transporter (DAT) site. It reflects primarily the integrity of presynaptic dopamine neuron terminals. With the evolution of the clinical features, the TRODAT SPECT images change from bilateral diminution of radioactivity uptake at the 81st-day check point to normal pattern at the 6-month one when the akinetic mute manifestations were nearly gone. This novel illustration suggests that the akinetic mutism caused by anterior cerebral arterial infarct is closely linked to the perturbation of the subcortical dopaminergic system. And the amelioration of the clinical features concordantly evolved with the restoration of the dopaminergic function.
Shikonin has been demonstrated to exhibit anti-cancer activity, but the underlying mechanisms are poorly understood. In this report, we showed that the administration of shikonin could result in the ...induction of apoptotic cell death of human hepatoma cell line, SK-Hep-1. As evident by the flow-cytometric studies, shikonin has the capability of generating increased amounts of intracellular reactive oxygen species (ROS) during the early stage of this apoptotic process (ca. one-hour), and subsequently accompanied by the dissipation of mitochondrial transmembrane potential (deltapsi (m)) at 3 hours. Further studies indicated that this apoptotic process could effectively be protected by the pretreatment of shikonin-treated cells with glutathione (GSH) and N-acetylcysteine (NAC), a precursor of GSH, but not by cyclosporin A (CyA), an inhibitor of mitochondrial permeability transition (MPT) pore. These data further proved that ROS-mediated oxidative stress was the pivotal element involved in the induction of apoptosis of SK-Hep-1 cells. Taken together, we suggest that shikonin-induced apoptosis of SK-Hep-1 cells proceeds by an oxidative stress-mediated pathway.
PDF
