Multi-Ethnic Norms for Volumes of Subcortical and Lobar Brain Structures Measured by Neuro I: Ethnicity May Improve the Diagnosis of Alzheimer's Disease1.

Background: We previously demonstrated the validity of a regression model that included ethnicity as a novel predictor for predicting normative brain volumes in old age. The model was optimized using brain volumes measured with a standard tool FreeSurfer. Objective: Here we further verified the prediction model using newly estimated brain volumes from Neuro I, a quantitative brain analysis system developed for Korean populations. Methods: Lobar and subcortical volumes were estimated from MRI images of 1,629 normal Korean and 786 Caucasian subjects (age range 59-89) and were predicted in linear regression from ethnicity, age, sex, intracranial volume, magnetic field strength, and scanner manufacturers. Results: In the regression model predicting the new volumes, ethnicity was again a substantial predictor in most regions. Additionally, the model-based z-scores of regions were calculated for 428 AD patients and the matched controls, and then employed for diagnostic classification. When the AD classifier adopted the z-scores adjusted for ethnicity, the diagnostic accuracy has noticeably improved (AUC = 0.85, ΔAUC = + 0.04, D = 4.10, p < 0.001). Conclusions: Our results suggest that the prediction model remains robust across different measurement tool, and ethnicity significantly contributes to the establishment of norms for brain volumes and the development of a diagnostic system for neurodegenerative diseases.

A magnetically powered nanomachine with a DNA clutch.

Machines found in nature and human-made machines share common components, such as an engine, and an output element, such as a rotor, linked by a clutch. This clutch, as seen in biological structures such as dynein, myosin or bacterial flagellar motors, allows for temporary disengagement of the moving parts from the running engine. However, such sophistication is still challenging to achieve in artificial nanomachines. Here we present a spherical rotary nanomotor with a reversible clutch system based on precise molecular recognition of built-in DNA strands. The clutch couples and decouples the engine from the machine's rotor in response to encoded inputs such as DNA or RNA. The nanomotor comprises a porous nanocage as a spherical rotor to confine the magnetic engine particle within the nanospace (∼0.004 µm3) of the cage. Thus, the entropically driven irreversible disintegration of the magnetic engine and the spherical rotor during the disengagement process is eliminated, and an exchange of microenvironmental inputs is possible through the nanopores. Our motor is only 200 nm in size and the clutch-mediated force transmission powered by an embedded ferromagnetic nanocrystal is high enough (∼15.5 pN at 50 mT) for the in vitro mechanical activation of Notch and integrin receptors, demonstrating its potential as nano-bio machinery.

Electron beam-induced demetallation of Fe, Co, Ni, Cu, Zn, Pd, and Pt metalloporphyrins: insights in e-beam chemistry and metal cluster formations.

Electron beams are versatile tools for nanoscale fabrication processes, however, the underlying e-beam chemistry remains in its infancy. Through operando transmission electron microscopy investigations, we elucidate a redox-driven cargo release of individual metal atoms triggered by electron beams. The chosen organic delivery molecule, tetraphenylporphyrin (TPP), proves highly versatile, forming complexes with nearly all metals from the periodic table and being easily processed in solution. A comprehensive cinematographic analysis of the dynamics of single metal atoms confirms the nearly instantaneous ejection of complexed metal atoms under an 80 kV electron beam, underscoring the system's broad versatility. Providing mechanistic insights, we employ density functional theory to support the proposed reductive demetallation pathway facilitated by secondary electrons, contributing novel perspectives to electron beam-mediated chemical reaction mechanisms. Lastly, our findings demonstrate that all seven metals investigated form nanoclusters once ejected from TPP, highlighting the method's potential for studying and developing sustainable single-atom and nanocluster catalysts.

Molecular Decrowding by Tissue Expansion Allows Precise Determination of the Spatial Distribution of Synaptic Proteins at a Nanometer Scale by exTEM.

To understand how the molecular machinery of synapses works, it is essential to determine an inventory of synaptic proteins at a subsynaptic resolution. Nevertheless, synaptic proteins are difficult to localize because of the low expression levels and limited access to immunostaining epitopes. Here, we report on the exTEM (epitope-exposed by expansion-transmission electron microscopy) method that enables the imaging of synaptic proteins in situ. This method combines TEM with nanoscale resolution and expandable tissue-hydrogel hybrids for enhanced immunolabeling with better epitope accessibility via molecular decrowding, allowing successful probing of the distribution of various synapse-organizing proteins. We propose that exTEM can be employed for studying the mechanisms underlying the regulation of synaptic architecture and function by providing nanoscale molecular distribution of synaptic proteins in situ. We also envision that exTEM is widely applicable for investigating protein nanostructures located in densely packed environments by immunostaining of commercially available antibodies at nanometer resolution.

Regulating the surface of anion-doped TiO2 nanorods by hydrogen annealing for superior photoelectrochemical water oxidation.

Dedications to achieve the highly efficient metal oxide semiconductor for the photoelectrochemical water splitting system have been persisted to utilize the TiO2 as the promising photoanode material. Herein, we report notable progress for nanostructured TiO2 photoanodes using facile sequential one-pot hydrothermal synthesis and annealing in hydrogen. A photocurrent density of 3.04 mA·cm-2 at 1.23 V vs. reversible hydrogen electrode was achieved in TiO2 nanorod arrays annealed in hydrogen ambient, which is approximately 4.25 times higher than that of pristine TiO2 annealed in ambient air. 79.2% of incident photon-to-current efficiency at 380 nm wavelength demonstrates the prominence of the material at the near-UV spectral range region and 100 h chronoamperometric test exhibits the stability of the photoanode. Detailed studies regarding crystallinity, bandgap, and elemental analysis provide the importance of the optimized annealing condition for the TiO2-based photoanodes. Water contact angle measurement displays the effect of hydrogen annealing on the hydrophilicity of the material. This study clearly demonstrates the marked improvement using the optimized hydrogen annealing, providing the promising methodologies for eco-friendly mass production of water splitting photoelectrodes.

Crystal Facet Engineering of TiO2 Nanostructures for Enhancing Photoelectrochemical Water Splitting with BiVO4 Nanodots.

Although bismuth vanadate (BiVO4) has been promising as photoanode material for photoelectrochemical water splitting, its charge recombination issue by short charge diffusion length has led to various studies about heterostructure photoanodes. As a hole blocking layer of BiVO4, titanium dioxide (TiO2) has been considered unsuitable because of its relatively positive valence band edge and low electrical conductivity. Herein, a crystal facet engineering of TiO2 nanostructures is proposed to control band structures for the hole blocking layer of BiVO4 nanodots. We design two types of TiO2 nanostructures, which are nanorods (NRs) and nanoflowers (NFs) with different (001) and (110) crystal facets, respectively, and fabricate BiVO4/TiO2 heterostructure photoanodes. The BiVO4/TiO2 NFs showed 4.8 times higher photocurrent density than the BiVO4/TiO2 NRs. Transient decay time analysis and time-resolved photoluminescence reveal the enhancement is attributed to the reduced charge recombination, which is originated from the formation of type II band alignment between BiVO4 nanodots and TiO2 NFs. This work provides not only new insights into the interplay between crystal facets and band structures but also important steps for the design of highly efficient photoelectrodes.

Neuroprotective Effects of a Wnt Antagonist in Quinolinic Acid-Induced Excitotoxicity in N18D3 Cells.

Excessive stimulation of the quinolinic acid induces neuronal cell death and is implicated in developing several neurodegenerative diseases. This study investigated whether a Wnt5a antagonist plays a neuroprotective role by regulating the Wnt pathway, activating cellular signaling mechanisms, including MAP kinase and ERK, and acting on the antiapoptotic and the proapoptotic genes in N18D3 neural cells. The cells were pretreated with a Wnt5a antagonist Box5, for one hour and then exposed to quinolinic acid (QUIN), an NMDA receptor agonist for 24 hours. An MTT assay and DAPI staining were used to evaluate cell viability and apoptosis, respectively, demonstrating that Box5 protected the cells from apoptotic death. In addition, a gene expression analysis revealed that Box5 prevented the QUIN-induced expression of the pro-apoptotic genes, BAD and BAX, and increased that of the anti-apoptotic genes, Bcl-xL, BCL2, and BCLW. Further examination of potential cell signaling candidates involved in this neuroprotective effect showed that the immunoreactivity of ERK was significantly increased in the cells treated with Box5. These results suggest that the neuroprotective mechanism of Box5 against QUIN-induced excitotoxic cell death involves the regulation of ERK and modulation of cell survival and death genes through decreasing the Wnt pathway, specifically Wnt5a.

Decoration of metal oxide surface with {111} form Au nanoparticles using PEGylation.

The benefit of introducing gold nanoparticles is due to the plasmon relaxation process. The plasmon decay induces various phenomena such as near-field enhancement, hot electron injection, and resonance energy transfer. Shape-controlled octahedral gold nanoparticles can maximize the efficiency of these processes. For practical purposes, a high-coverage decoration method, comparable to physical vapor deposition on a metal oxide semiconductor nanostructure, is indispensable. However, the ligand exchange reaction to attach octahedral gold nanoparticles is limited in aqueous solution due to the inactivity of the gold (111) surface as a result of a densely-packed cetyltrimethylammonium bilayer structure. Herein, we report a controllable high-coverage surface decoration method of octahedral gold nanoparticles on the targeted semiconductor nanostructures via phase transfer by an organic medium with thiolated-polyethylene glycol. Our results deliver an innovative platform for future plasmonic gold nanoparticle applications.

Non-canonical Wnt mediated neurogenic differentiation of human bone marrow-derived mesenchymal stem cells.

Bone marrow-derived mesenchymal stem cells (BM-MSCs), which are characterized by multipotency and self-renewal, are responsible for tissue regeneration and repair. We have previously reported in adipose tissue-derived MSCs that only Wnt5a is enhanced at neurogenic differentiation, and the mechanism of differentiation is dependent on the Wnt5a/JNK pathway; however, the role of Wnt/MAPK pathway is yet to be investigated in neurogenic differentiation in BM-MSCs. We compared the transcriptional expression of Wnt in neurogenic induced-hBM-MSCs (NI-hBM-MSCs) with that in primary hBM-MSCs, using RT-PCR, qPCR, and western blotting. Although the expression of Wnt1 and Wnt2 was unchanged, the expression of Wnt4, Wnt5a, and Wnt11 increased after neurogenic differentiation. In addition, only the expression of frizzled class receptor (Fzd) 3 gene was increased, but not of most of the Fzds and Wnt ligands in NI-hBM-MSCs. Interestingly, Wnt4, Wnt5a, and Wnt11 gene expressions significantly increased in NI-hBM-MSCs by qPCR. In addition, the protein expression level of Wnt4 and Wnt5a, but not Wnt3, increased after neurogenic induction. Furthermore, the expressions of phosphorylated-GSK-3ß, ERK1/2, and PKC decreased; however, JNK was activated after neurogenic differentiation. Thus, non-canonical Wnts, i.e., Wnt4, Wnt5a, and Wnt11, regulate neurogenic differentiation through Fzd3 activation and the increase in downstream targets of JNK, which is one of the non-canonical pathways, in hBM-MSCs.

Transplantation of human adipose tissue-derived stem cells for repair of injured spiral ganglion neurons in deaf guinea pigs.

Excessive noise, ototoxic drugs, infections, autoimmune diseases, and aging can cause loss of spiral ganglion neurons, leading to permanent sensorineural hearing loss in mammals. Stem cells have been confirmed to be able to differentiate into spiral ganglion neurons. Little has been reported on adipose tissue-derived stem cells (ADSCs) for repair of injured spiral ganglion neurons. In this study, we hypothesized that transplantation of neural induced-human ADSCs (NI-hADSCs) can repair the injured spiral ganglion neurons in guinea pigs with neomycin-induced sensorineural hearing loss. NI-hADSCs were induced with culture medium containing basic fibroblast growth factor and forskolin and then injected to the injured cochleae. Guinea pigs that received injection of Hanks' balanced salt solution into the cochleae were used as controls. Hematoxylin-eosin staining showed that at 8 weeks after cell transplantation, the number of surviving spiral ganglion neurons in the cell transplantation group was significantly increased than that in the control group. Also at 8 weeks after cell transplantation, immunohistochemical staining showed that a greater number of NI-hADSCs in the spiral ganglions were detected in the cell transplantation group than in the control group, and these NI-hADSCs expressed neuronal markers neurofilament protein and microtubule-associated protein 2. Within 8 weeks after cell transplantation, the guinea pigs in the cell transplantation group had a gradually decreased auditory brainstem response threshold, while those in the control group had almost no response to 80 dB of clicks or pure tone burst. These findings suggest that a large amount of NI-hADSCs migrated to the spiral ganglions, survived for a period of time, repaired the injured spiral ganglion cells, and thereby contributed to the recovery of sensorineural hearing loss in guinea pigs.

Pituitary Adenylate Cyclase-activating Polypeptide Inhibits Pacemaker Activity of Colonic Interstitial Cells of Cajal.

This study aimed to investigate the effect of pituitary adenylate cyclase-activating peptide (PACAP) on the pacemaker activity of interstitial cells of Cajal (ICC) in mouse colon and to identify the underlying mechanisms of PACAP action. Spontaneous pacemaker activity of colonic ICC and the effects of PACAP were studied using electrophysiological recordings. Exogenously applied PACAP induced hyperpolarization of the cell membrane and inhibited pacemaker frequency in a dose-dependent manner (from 0.1 nM to 100 nM). To investigate cyclic AMP (cAMP) involvement in the effects of PACAP on ICC, SQ-22536 (an inhibitor of adenylate cyclase) and cell-permeable 8-bromo-cAMP were used. SQ-22536 decreased the frequency of pacemaker potentials, and cell-permeable 8-bromo-cAMP increased the frequency of pacemaker potentials. The effects of SQ-22536 on pacemaker potential frequency and membrane hyperpolarization were rescued by co-treatment with glibenclamide (an ATP-sensitive K(+) channel blocker). However, neither N (G)-nitro-L-arginine methyl ester (L-NAME, a competitive inhibitor of NO synthase) nor 1H-[1,2,4]oxadiazolo[4,3-α]quinoxalin-1-one (ODQ, an inhibitor of guanylate cyclase) had any effect on PACAP-induced activity. In conclusion, this study describes the effects of PACAP on ICC in the mouse colon. PACAP inhibited the pacemaker activity of ICC by acting through ATP-sensitive K(+) channels. These results provide evidence of a physiological role for PACAP in regulating gastrointestinal (GI) motility through the modulation of ICC activity.

Neural Differentiation of Human Adipose Tissue-Derived Stem Cells Involves Activation of the Wnt5a/JNK Signalling.

Stem cells are a powerful resource for cell-based transplantation therapies, but understanding of stem cell differentiation at the molecular level is not clear yet. We hypothesized that the Wnt pathway controls stem cell maintenance and neural differentiation. We have characterized the transcriptional expression of Wnt during the neural differentiation of hADSCs. After neural induction, the expressions of Wnt2, Wnt4, and Wnt11 were decreased, but the expression of Wnt5a was increased compared with primary hADSCs in RT-PCR analysis. In addition, the expression levels of most Fzds and LRP5/6 ligand were decreased, but not Fzd3 and Fzd5. Furthermore, Dvl1 and RYK expression levels were downregulated in NI-hADSCs. There were no changes in the expression of ß-catenin and GSK3ß. Interestingly, Wnt5a expression was highly increased in NI-hADSCs by real time RT-PCR analysis and western blot. Wnt5a level was upregulated after neural differentiation and Wnt3, Dvl2, and Naked1 levels were downregulated. Finally, we found that the JNK expression was increased after neural induction and ERK level was decreased. Thus, this study shows for the first time how a single Wnt5a ligand can activate the neural differentiation pathway through the activation of Wnt5a/JNK pathway by binding Fzd3 and Fzd5 and directing Axin/GSK-3ß in hADSCs.

Neural-induced human mesenchymal stem cells promote cochlear cell regeneration in deaf Guinea pigs.

OBJECTIVES: In mammals, cochlear hair cell loss is irreversible and may result in a permanent sensorineural hearing loss. Secondary to this hair cell loss, a progressive loss of spiral ganglion neurons (SGNs) is presented. In this study, we have investigated the effects of neural-induced human mesenchymal stem cells (NI-hMSCs) from human bone marrow on sensory neuronal regeneration from neomycin treated deafened guinea pig cochleae. METHODS: HMSCs were isolated from the bone marrow which was obtained from the mastoid process during mastoidectomy for ear surgery. Following neural induction with basic fibroblast growth factor and forskolin, we studied the several neural marker and performed electrophysiological analysis. NI-hMSCs were transplanted into the neomycin treated deafened guinea pig cochlea. Engraftment of NI-hMSCs was evaluated immunohistologically at 8 weeks after transplantation. RESULTS: Following neural differentiation, hMSCs expressed high levels of neural markers, ionic channel markers, which are important in neural function, and tetrodotoxin-sensitive voltage-dependent sodium currents. After transplantation into the scala tympani of damaged cochlea, NI-hMSCs-injected animals exhibited a significant increase in the number of SGNs compared to Hanks balanced salt solution-injected animals. Transplanted NI-hMSCs were found within the perilymphatic space, the organ of Corti, along the cochlear nerve fibers, and in the spiral ganglion. Furthermore, the grafted NI-hMSCs migrated into the spiral ganglion where they expressed the neuron-specific marker, NeuN. CONCLUSION: The results show the potential of NI-hMSCs to give rise to replace the lost cochlear cells in hearing loss mammals.

Synthesis and evaluation of 5-(3-(pyrazin-2-yl)benzylidene)thiazolidine-2,4-dione derivatives as pan-pim kinases inhibitors.

Pim kinases play a key role in the regulation of signaling pathways including proliferation, migration, and metabolism and are a potential target for cancer therapy. A series of 5-benzylidenethiazolidine-2,4-diones were synthesized as pim kinase inhibitors. The structure-activity relationships (SAR) of the analogues in inhibiting in vitro pim kinase activity as well as the proliferation of leukemia cell lines were examined. SAR studies indicated that a hydroxyl group at the 2-position of the benzene ring of 5-benzylidenethiazolidine-2,4-dione plays an important role in the inhibitory activity against all three pim kinases and replacement with a pyrazinyl group at the 5-position of the benzene ring of 5-benzylidenethiazolidine-2,4-dione improved activity significantly. The compounds exerted anti-proliferative activity against the three leukemia cell lines we tested. The most potent compound, 5i, had an EC50 value of 0.8 µM in the MV4-11 cell line. The result of kinase profiling indicated that compound 5i was highly selective for pim-kinases.

The neuroprotective effect of carnosine (ß-alanyl-L-histidine) on retinal ganglion cell following ischemia-reperfusion injury.

PURPOSE: To investigate whether carnosine can increase retinal ganglion cell (RGC) survival in ischemic mouse retina. METHODS: Retinal ischemia was induced by constant elevation of intraocular pressure (100-110 mmHg) for 60 min in C57BL/6 J mice pretreated with carnosine (1000 mg/kg) or saline. Hypoxia inducing factor-1 alpha (HIF-1α), glial fibrillary acidic protein (GFAP), and dynamin-related protein-1 (Drp-1) expressions were assessed at 6, 12, and 24 h after retinal ischemia. Bax and Bcl-2 expressions were also analyzed at 12 h after retinal ischemia. RGC survival was assessed by retrograde FluoroGold labeling at 2 weeks after retinal ischemia. RESULTS: The expression of HIF-1α, GFAP, and Drp-1 was increased within 24 h after ischemic injury. Carnosine treatment effectively decreased the elevated expression of HIF-1α, GFAP, and Drp-1 in ischemic mouse retina. In ischemic retina treated with carnosine, Bax expression was decreased, whereas Bcl-2 expression was increased compared with ischemic retina treated with saline. Carnosine treatment also protected against RGC loss in ischemia mouse retina. CONCLUSIONS: Our findings showed that carnosine treatment significantly decreased RGC loss through decreased expression of HIF-1α, GFAP, Drp-1, and Bax, and increased expression of Bcl-2 in ischemic mouse retina. We suggest that carnosine can be an effective endogenous neuroprotective molecule in the prevention of RGC loss in ischemic retina.

Establishment of a protocol for determining gastrointestinal transit time in mice using barium and radiopaque markers.

OBJECTIVE: The purpose of this study was to establish a minimally invasive and reproducible protocol for estimating the gastrointestinal (GI) transit time in mice using barium and radiopaque markers. MATERIALS AND METHODS: Twenty 5- to 6-week-old Balb/C female mice weighing 19-21 g were used. The animals were divided into three groups: two groups that received loperamide and a control group. The control group (n = 10) animals were administered physiological saline (1.5 mL/kg) orally. The loperamide group I (n = 10) and group II (n = 10) animals were administered 5 mg/kg and 10 mg/kg loperamide orally, respectively. Thirty minutes after receiving the saline or loperamide, the mice was administered 80 µL of barium solution and six iron balls (0.5 mm) via the mouth and the upper esophagus by gavage, respectively. Afterwards, the mice were continuously monitored with fluoroscopic imaging in order to evaluate the swallowing of the barium solution and markers. Serial fluoroscopic images were obtained at 5- or 10-min intervals until all markers had been excreted from the anal canal. For analysis, the GI transit times were subdivided into intestinal transit times (ITTs) and colon transit times (CTTs). RESULTS: The mean ITT was significantly longer in the loperamide groups than in the control group (p < 0.05). The mean ITT in loperamide group II (174.5 ± 32.3) was significantly longer than in loperamide group I (133.2 ± 24.2 minute) (p < 0.05). The mean CTT was significantly longer in loperamide group II than in the control group (p < 0.05). Also, no animal succumbed to death after the experimental procedure. CONCLUSION: The protocol for our study using radiopaque markers and barium is reproducible and minimally invasive in determining the GI transit time of the mouse model.

Spontaneous electrical activity of cultured interstitial cells of cajal from mouse urinary bladder.

Interstitial cells of Cajal (ICCs) from the urinary bladder regulate detrusor smooth muscle activities. We cultured ICCs from the urinary bladder of mice and performed patch clamp and intracellular Ca(2+) ([Ca(2+)]i) imaging to investigate whether cultured ICCs can be a valuable tool for cellular functional studies. The cultured ICCs displayed two types of spontaneous electrical activities which are similar to those recorded in intact bladder tissues. Spontaneous electrical activities of cultured ICCs were nifedipine-sensitive. Carbachol and ATP, both excitatory neurotransmitters in the urinary bladder, depolarized the membrane and increased the frequency of spike potentials. Carbachol increased [Ca(2+)]i oscillations and basal Ca(2+) levels, which were blocked by atropine. These results suggest that cultured ICCs from the urinary bladder retain rhythmic phenotypes similar to the spontaneous electrical activities recorded from the intact urinary bladder. Therefore, we suggest that cultured ICCs from the urinary bladder may be useful for cellular and molecular studies of ICCs.

Subclinical Myocardial Dysfunction in Metabolic Syndrome Patients without Hypertension.

BACKGROUND: The aim of this study was to evaluate myocardial function in patients with non-hypertensive metabolic syndrome. METHODS: We selected metabolic syndrome patients (n = 42) without evidence of hypertension and compared them to age-matched control individuals (n = 20). All patients were evaluated by two-dimensional and tissue Doppler echocardiography including tissue Doppler derived strain and strain rate measurements. RESULTS: There were no significant differences between the two groups in mitral E and A inflow velocities or the E/A ratio. However, systolic and early diastolic myocardial velocities, and strain rate were significantly lower in patients with metabolic syndrome than in the control group (all p < 0.05). Multiple stepwise regression analyses revealed that age, waist circumference, and systolic blood pressure were independently associated with peak systolic myocardial velocity. CONCLUSION: These results indicate that metabolic syndrome patients without hypertension may have decrease of myocardial systolic and early diastolic velocities on tissue Doppler imaging, even if they appear to have normal systolic and diastolic function on conventional echocardiography.

Effects of sphingosine-1-phosphate on neural differentiation and neurite outgrowth in neuroblastoma cells.

Sphingosine-1-phosphate (S1P) is emerging as a new class of second messenger involved in cellular proliferation, differentiation, and apoptosis and is implicated in diverse physiological functions. Despite many studies on the biological functions of S1P, however, little is known about its role in neuronal differentiation. By use of reverse transcription-polymerase chain reaction and immunostaining, this study aimed to explore whether S1P can differentiate neuroblastoma cells into neural cells. After incubation with 1 uM or 10 uM S1P, the number of neurite-bearing cells increased. Furthermore, the neuroblastoma cells revealed immunoreactivity for neural-specific markers such as GAP43, NFH, and SYP by immunostaining. The expression of NFH, MAP2, SYP, NeuroD1, and SYT mRNA, which is specific for neurons, was increased as shown by RT-PCR studies. The results of this study suggest that that S1P can induce neuronal differentiation and may be a good candidate for the treatment of neurodegenerative diseases.

Effects of Epigallocatechin-3-Gallate on the Expression of TGF-ß1, PKC α/ßII, and NF-κB in High-Glucose-Stimulated Glomerular Epithelial Cells.

Epigallocatechin-3-gallate (EGCG) is the most potent antioxidant polyphenol in green tea. In the present study, we investigated whether EGCG plays a role in the expression of transforming growth factor-beta1 (TGF-ß1), protein kinase C (PKC) α/ßII, and nuclear factor-kappaB (NF-κB) in glomerular epithelial cells (GECs) against high-glucose injury. Treatment with high glucose (30 mM) increased reactive oxygen species (ROS)/lipid peroxidation (LPO) and decreased glutathione (GSH) in GECs. Pretreatment with 100 µM EGCG attenuated the increase in ROS/LPO and restored the levels of GSH, whereas ROS, LPO, and GSH levels were not affected by treatment with 30 mM mannitol as an osmotic control. Interestingly, high-glucose treatment affected 3 separate signal transduction pathways in GECs. It increased the expression of TGF-ß1, PKC α/ßII, and NF-κB in GECs, respectively. EGCG (1, 10, 100 µM) pretreatment significantly decreased the expression of TGF-ß1 induced by high glucose in a dose-dependent manner. In addition, EGCG (100 µM) inhibited the phosphorylation of PKC α/ßII caused by glucose at 30 mM. Moreover, EGCG (1, 10, 100 µM) pretreatment significantly decreased the transcriptional activity of NF-κB induced by high glucose in a dose-dependent manner. These data suggest that EGCG could be a useful factor in modulating the injury to GECs caused by high glucose.