Ghrelin Represses Thymic Stromal Lymphopoietin Gene Expression through Activation of Glucocorticoid Receptor and Protein Kinase C Delta in Inflamed Skin Keratinocytes.

Ghrelin, a peptide hormone secreted from enteroendocrine cells of the gastrointestinal tract, has anti-inflammatory activity in skin diseases, including dermatitis and psoriasis. However, the molecular mechanism underlying the beneficial effect of ghrelin on skin inflammation is not clear. In this study, we found that ghrelin alleviates atopic dermatitis (AD)-phenotypes through suppression of thymic stromal lymphopoietin (TSLP) gene activation. Knockdown or antagonist treatment of growth hormone secretagogue receptor 1a (GHSR1a), the receptor for ghrelin, suppressed ghrelin-induced alleviation of AD-like phenotypes and suppression of TSLP gene activation. We further found that ghrelin induces activation of the glucocorticoid receptor (GR), leading to the binding of GR with histone deacetylase 3 (HDAC3) and nuclear receptor corepressor (NCoR) NCoR corepressor to negative glucocorticoid response element (nGRE) on the TSLP gene promoter. In addition, ghrelin-induced protein kinase C δ (PKCδ)-mediated phosphorylation of p300 at serine 89 (S89), which decreased the acetylation and DNA binding activity of nuclear factor- κB (NF-κB) p65 to the TSLP gene promoter. Knockdown of PKCδ abolished ghrelin-induced suppression of TSLP gene activation. Our study suggests that ghrelin may help to reduce skin inflammation through GR and PKCδ-p300-NF-κB-mediated suppression of TSLP gene activation.

Total saponin extract, ginsenoside Rb1, and compound K alleviate peripheral and central neuropathic pain through estrogen receptors on rats.

In this study, we investigated whether total saponin extract (TSE), ginsenoside Rb1, and Rb1 metabolite compound K, which are isolated from red ginseng, have antinociceptive effects on peripheral and central neuropathic pain (PNP and CNP, respectively). PNP and CNP were induced by tail nerve injury (TNI) at S1 and by contusive spinal cord injury (SCI) at T9 in male Sprague-Dawley rats, respectively. Two weeks after TNI or 4 weeks after SCI, pain-induced rats were orally administered vehicle, TSE (50 mg/kg), Rb1 (12.5 mg/kg), compound K (7 mg/kg), or gabapentin (GBP, 60 mg/kg), and the antinociceptive effects were examined by von Frey filament, cold/warm water, and hot plate analyses. Allodynia and hyperalgesia were significantly alleviated by TSE, Rb1, and GBP 1 hr after drug administration. The immunohistochemistry and real-time RT-PCR results showed that the activation of microglia/astrocytes and the expression of inflammatory mediators such as Il-1ß, Il-6, iNOS, and Cox-2 were also significantly inhibited in L4-L5 spinal cord of CNP-induced rats 1 hr after drug administration. Furthermore, the antinociceptive effects of TSE and Rb1 were reversed by treatment with the estrogen receptor (ER) antagonist ICI182780. In particular, compound K also significantly alleviated both PNP and CNP. Therefore, our results indicate that TSE, Rb1, and compound K have potential antinociceptive effects against neuropathic pain that might be mediated through the ER.

Gallic acid attenuates blood-spinal cord barrier disruption by inhibiting Jmjd3 expression and activation after spinal cord injury.

After spinal cord injury (SCI), blood-spinal cord barrier (BSCB) disruption results in secondary injury including apoptotic cell death of neurons and oligodendrocytes, thereby leads to permanent neurological deficits. Recently, we reported that the histone H3K27me3 demethylase Jmjd3 plays a role in regulating BSCB integrity after SCI. Here, we investigated whether gallic acid (GA), a natural phenolic compound that is known to be anti-inflammatory, regulates Jmjd3 expression and activation, thereby attenuates BSCB disruption following the inflammatory response and improves functional recovery after SCI. Rats were contused at T9 and treated with GA (50 mg/kg) via intraperitoneal injection immediately, 6 h and 12 h after SCI, and further treated for 7 d with the same dose once a day. To elucidate the underlying mechanism, we evaluated Jmjd3 activity and expression, and assessed BSCB permeability by Evans blue assay after SCI. GA significantly inhibited Jmjd3 expression and activation after injury both in vitro and in vivo. GA also attenuated the expression and activation of matrix metalloprotease-9, which is well known to disrupt the BSCB after SCI. Consistent with these findings, GA attenuated BSCB disruption and reduced the infiltration of neutrophils and macrophages compared with the vehicle control. Finally, GA significantly alleviated apoptotic cell death of neurons and oligodendrocytes and improved behavior functions. Based on these data, we propose that GA can exert a neuroprotective effect by inhibiting Jmjd3 activity and expression followed the downregulation of matrix metalloprotease-9, eventually attenuating BSCB disruption after SCI.

Implantation of a Matrigel-loaded agarose scaffold promotes functional regeneration of axons after spinal cord injury in rat.

An agarose scaffold can be useful for supporting and guiding injured axons after spinal cord injury (SCI), but the electrophysiological signal of regenerated axon in scaffolds has not yet been determined. The current study investigated whether a Matrigel-loaded agarose scaffold would enhance the regeneration of axons after SCI. Moreover, the functional connectivity of regenerated axons within the channels of the scaffold was evaluated by directly recording motor evoked potentials. Our data showed that the agarose scaffold containing Matrigel can support and enhance linearly organized axon regeneration after SCI. Additionally, motor evoked potentials were successfully recorded from regenerated axons. These results demonstrate that an agarose scaffold loaded with Matrigel could promote the regeneration of axons and guide the reconnection of functional axons after SCI.

Estrogen alleviates neuropathic pain induced after spinal cord injury by inhibiting microglia and astrocyte activation.

Neuropathic pain after spinal cord injury (SCI) is developed in about 80% of SCI patients and there is no efficient therapeutic drug to alleviate SCI-induced neuropathic pain. Here we examined the effect of estrogen on SCI-induced neuropathic pain at below-level and its effect on neuroinflammation as underlying mechanisms. Neuropathic pain is developed at late phase after SCI and a single dose of 17ß-estradiol (100, 300 µg/kg) were administered to rats with neuropathic pain after SCI through intravenous injection. As results, both mechanical allodynia and thermal hyperalgesia were significantly reduced by 17ß-estradiol compared to vehicle control. Both microglia and astrocyte activation in the lamina I and II of L4-5 dorsal horn was also inhibited by 17ß-estradiol. In addition, the levels of p-p38MAPK and p-ERK known to be activated in microglia and p-JNK known to be activated in astrocyte were significantly decreased by 17ß-estradiol. Furthermore, the mRNA expression of inflammatory mediators such as Il-1ß, Il-6, iNos, and Cox-2 was more attenuated in 17ß-estradiol-treated group than in vehicle-treated group. Particularly, we found that the analgesic effect by 17ß-estradiol was mediated via estrogen receptors, which are expressed in dorsal horn neurons. These results suggest that 17ß-estradiol may attenuate SCI-induced neuropathic pain by inhibiting microglia and astrocyte activation followed inflammation.

Matrix metalloproteinase-3 promotes early blood-spinal cord barrier disruption and hemorrhage and impairs long-term neurological recovery after spinal cord injury.

After spinal cord injury (SCI), blood-spinal cord barrier (BSCB) disruption by matrix metalloproteinases (MMPs) leads to BSCB permeability and blood cell infiltration, contributing to permanent neurological disability. Herein, we report that MMP-3 plays a critical role in BSCB disruption after SCI in mice. MMP-3 was induced in infiltrated neutrophils and blood vessels after SCI, and NF-κB as a transcription factor was involved in MMP-3 expression. BSCB permeability and blood cell infiltration after injury were more reduced in Mmp3 knockout (KO) mice than in wild-type (WT) mice, which was significantly inhibited by Mmp3 siRNA or a general inhibitor of MMPs, N-isobutyl-N-(4-methoxyphenylsulfonyl)glycyl hydroxamic acid. The level of tight junction proteins, such as occludin and zonula occludens-1, which decreased after SCI, was also higher in Mmp3 KO than in WT mice. Exogenously, MMP-3 injection into the normal spinal cord also induced BSCB permeability. Furthermore, MMP-9 activation after injury was mediated by MMP-3 activation. Finally, improved functional recovery was observed in Mmp3 KO mice compared with WT mice after injury. These results demonstrated the role of MMP-3 in BSCB disruption after SCI for the first time and suggest that the regulation of MMP-3 can be considered a therapeutic target to inhibit BSCB disruption and hemorrhage, and thereby enhance functional recovery after acute SCI.

3-Benzamides and 3,4,5-trimethoxyphenyl amines as calcium channel blockers.

T- and N-type calcium channels have known for relating to therapy of neuropathic pain which is chronic, debilitating pain state. Neuropathic pain is caused by damage of the somatosensory system. It may be associated with abnormal sensations and pain produced by normally non-painful stimuli (allodynia). Neuropathic pain is very difficult to treat, and only some 40-60% of patients achieve partial relief. For a neuropathic pain therapy, anticonvulsant like Lamotrigine, Carbamazepine and a topical anesthetic such as Lidocaine are used. We synthesized 15 novel amine derivatives and evaluated their activities against T-type and N-type calcium channels by whole-cell patch clamp recording on HEK293 cells. Among the tested compounds, compound 10 showed good inhibitory activity for both T-type and N-type calcium channels with the IC50 value of 1.9 µM and 4.3 µM, respectively. Compound 10 also showed good analgesic activity on rat spinal cord injury model.

TRPM7 Mediates Neuropathic Pain by Activating mTOR Signaling in Astrocytes after Spinal Cord Injury in Rats.

In this study, we investigated whether transient receptor melastatin 7 (TRPM7), known as a non-selective cation channel, inhibits neuropathic pain after spinal cord injury (SCI) and how TRPM7 regulates neuropathic pain. Neuropathic pain was developed 4 weeks after moderate contusive SCI and TRPM7 was markedly upregulated in astrocytes in the lamina I and II of L4-L5 dorsal horn. In addition, both mechanical allodynia and thermal hyperalgesia were significantly alleviated by a TRPM7 inhibitor, carvacrol. In particular, carvacrol treatment inhibited mechanistic target of rapamycin (mTOR) signaling, which was activated in astrocytes. When rats were treated with rapamycin, an inhibitor of mTOR signaling, neuropathic pain was significantly inhibited. Furthermore, blocking TRPM7 and mTOR signaling by carvacrol and rapamycin inhibited astrocyte activation in lamina I and II of dorsal spinal cord and reduced the level of p-JNK and p-c-Jun, which are known to be activated in astrocytes. Finally, inhibiting TRPM7/mTOR signaling also downregulated the production of pain-related factors such as tumor necrosis factor-α, interleukin-6, interleukin-1ß, chemokine (C-C motif) ligand (CCL) 2, CCL-3, CCL-4, CCL-20, chemokine C-X-C motif ligand 1, and matrix metalloproteinase 9 which are known to be involved in the induction and/or maintenance of neuropathic pain after SCI. These results suggest an important role of TRPM7-mediated mTOR signaling in astrocyte activation and thereby induction and/or maintenance of neuropathic pain after SCI.

TRPM7 Mediates BSCB Disruption After Spinal Cord Injury by Regulating the mTOR/JMJD3 Axis in Rats.

After spinal cord injury (SCI), secondary injuries including blood cells infiltration followed by the production of inflammatory mediators are led by blood-spinal cord barrier (BSCB) breakdown. Therefore, preventing BSCB damage could alleviate the secondary injury progresses after SCI. Recently, we reported that transient receptor potential melastatin 7 channel (TRPM7) expression is increased in vascular endothelial cells after injury and thereby mediates BSCB disruption. However, the mechanism by which TRPM7 regulates BSCB disruption has not been examined yet. In current research, we show that TRPM7 mediates BSCB disruption via mammalian target of rapamycin (mTOR) pathway after SCI in rats. After contusion injury at T9 level of spinal cord, mTOR pathway was activated in the endothelial cells of blood vessels and TRPM7 was involved in the activation of mTOR pathway. BSCB disruption, MMP-2/9 activation, and blood cell infiltration after injury were alleviated by rapamycin, a mTOR signaling inhibitor. Rapamycin also conserved the level of tight junction proteins, which were decreased after SCI. Furthermore, mTOR pathway regulated the expression and activation of histone H3K27 demethylase JMJD3, known as a key epigenetic regulator mediating BSCB damage after SCI. In addition, rapamycin inhibited JMJD3 expression, the loss of tight junction molecules, and MMP-2/9 expression in bEnd.3, a brain endothelial cell line, after oxygen-glucose deprivation/reoxygenation. Thus, our results suggest that TRPM7 contributes to the BSCB disruption by regulating JMJD3 expression through the mTOR pathway after SCI.

MMP-3 contributes to nigrostriatal dopaminergic neuronal loss, BBB damage, and neuroinflammation in an MPTP mouse model of Parkinson's disease.

The present study examined whether matrix metalloproteinase-3 (MMP-3) participates in the loss of dopaminergic (DA) neurons in the nigrostriatal pathway in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease with blood brain barrier (BBB) damage and infiltration of peripheral immune cells. Tyrosine hydroxylase (TH) immunostaining of brain sections from MPTP-treated mice showed that MPTP induced significant degeneration of nigrostriatal DA neurons. Moreover, FITC-labeled albumin detection and immunostaining revealed that MPTP caused damage to the BBB and increased the number of ED-1- and CD-3-immunopositive cells in the substantia nigra (SN). Genetic ablation of MMP-3 reduced the nigrostriatal DA neuron loss and improved motor function. This neuroprotective effect afforded by MMP-3 deletion was associated with the suppression of BBB disruption and a decrease in the number of ED-1- and CD-3-immunopositive cells in the SN. These data suggest that MMP-3 could play a crucial role in neurodegenerative diseases such as PD in which BBB damage and neuroinflammation are implicated.

GSK-3ß and ß-Catenin Signaling Pathway is Involved in Myofibroblast Transition of Ligamentum Flavum in Lumbar Spinal Stenosis Patients.

STUDY DESIGN: Histologic analysis of the ligamentum flavum (LF) in the lumbar spine. OBJECTIVE: The objective of this study is to investigate the levels of glycogen synthase kinase-3ß (GSK-3ß) and ß-catenin in the LF tissue of patients with lumbar spinal stenosis (LSS). SUMMARY OF BACKGROUND DATA: The hypertrophy of the LF is the primary cause of the progression of LSS. Recently, Wnt signaling has been proposed as one of the molecular processes contributing to LF hypertrophy. GSK-3ß and ß-catenin are recognized to play a crucial part in the control of this signaling pathway. MATERIALS AND METHODS: From May 2020 to July 2022, LF from 51 LSS patients (LSS group) and 18 lumbar disc herniation patients (control group) were prospectively collected during surgery. Histologic analysis was investigated to confirm the progression of LF fibrosis. The levels of α-smooth muscle actin, phosphorylation of GSK-3ß (p-GSK-3ß; inactive form), and ß-catenin were analyzed in LF with Western blot analysis to reveal the GSK-3ß/ß-catenin signaling pathway. Continuous variables are expressed as mean±SD and compared using the student t test. Categorical variables are compared using the χ 2 test or Fisher exact test, as appropriate. To determine the association between p-GSK-3ß and LF thickness, the Pearson correlation coefficient was calculated based on the results of Western blot analysis. RESULTS: The LSS group was older and had thicker LF than the controls. The LSS group showed increased collagen fiber and cellularity than the controls. The levels of α-smooth muscle actin, p-GSK-3ß, and ß-catenin in the LF of the LSS group were significantly higher than that of the control group. There was a strong positive correlation between p-GSK-3ß (Ser9) level and LF thickness in LSS patients ( r =0.69, P =0.01). CONCLUSION: This research proposes a molecular mechanism for the pathogenesis of LF hypertrophy in LSS. Specifically, GSK-3ß/ß-catenin signaling appears to be related to LF hypertrophy in LSS and a positive correlation exists between p-GSK-3ß level and LF thickness. LEVEL OF EVIDENCE: Level 3.

IL-6/JAK2/STAT3 axis mediates neuropathic pain by regulating astrocyte and microglia activation after spinal cord injury.

After spinal cord injury (SCI), the control of activated glial cells such as microglia and astrocytes has emerged as a promising strategy for neuropathic pain management. However, signaling mechanism involved in glial activation in the process of neuropathic pain development and maintenance after SCI is not well elucidated. In this study, we investigated the potential role and mechanism of the JAK2/STAT3 pathway associated with glial cell activation in chronic neuropathic pain development and maintenance after SCI. One month after contusive SCI, the activation of JAK2/STAT3 pathway was markedly upregulated in both microglia and astrocyte in nociceptive processing regions of the lumbar spinal cord. In addition, both mechanical allodynia and thermal hyperalgesia was significantly inhibited by a JAK2 inhibitor, AG490. In particular, AG490 treatment inhibited both microglial and astrocyte activation in the lumbar (L) 4-5 dorsal horn and significantly decreased levels of p-p38MAPK, p-ERK and p-JNK, which are known to be activated in microglia (p-p38MAPK and p-ERK) and astrocyte (p-JNK). Experiments using primary cell cultures also revealed that the JAK2/STAT3 pathway promoted microglia and astrocyte activation after lipopolysaccharide stimulation. Furthermore, JAK2/STAT3 signaling and pain behaviors were significantly attenuated when the rats were treated with anti-IL-6 antibody. Finally, minocycline, a tetracycline antibiotic, inhibited IL-6/JAK2/STAT3 signaling pathway in activated glial cells and restored nociceptive thresholds and the hyperresponsiveness of dorsal neurons. These results suggest an important role of the IL-6/JAK2/STAT3 pathway in the activation of microglia and astrocytes and in the maintenance of chronic below-level pain after SCI.

Molecular mechanism of Jmjd3-mediated interleukin-6 gene regulation in endothelial cells underlying spinal cord injury.

The inflammatory response contributes substantially to secondary injury cascades after spinal cord injury, with both neurotoxic and protective effects. However, epigenetic regulations of inflammatory genes following spinal cord injury have yet to be characterized thoroughly. In this study, we found that histone H3K27me3 demethylase Jmjd3 expression is acutely up-regulated in blood vessels of the injured spinal cord. We also observed up-regulation of Jmjd3 gene expression in bEnd.3 endothelial cells that were subjected to oxygen-glucose deprivation/reperfusion injury. When Jmjd3 was depleted by siRNA, oxygen-glucose deprivation/reperfusion injury-induced up-regulation of IL-6 was significantly inhibited. In addition, Jmjd3 associated with NF-κB (p65/p50) and CCAAT-enhancer-binding protein ß at the IL-6 gene promoter. The recruitment of Jmjd3 coincided with decreased levels of tri-methylated H3K27 as well as increased levels of mono-methylated H3K27 at the IL-6 gene promoter. Furthermore, Jmjd3 depletion did not result in significant changes of methylation level of H3K27 at the IL-6 gene promoter. Collectively, our findings imply that Jmjd3-mediated H3K27me3 demethylation is crucial for IL-6 gene activation in endothelial cells, and this molecular event may regulate acute inflammatory response and integrity of the blood-spinal cord barrier following spinal cord injury.

IKK-ß-mediated myeloid cell activation exacerbates inflammation and inhibits recovery after spinal cord injury.

Traumatic spinal cord injury (SCI) is followed by massive infiltration and activation of myeloid cells such as neutrophils and macrophages, but the functions of these cells are controversial. In this study, our objective was to elucidate the in vivo role of a signaling pathway involved in activation of these innate immune cells in SCI using myeloid cell-specific IκB kinase (IKK)-ß conditional knockout (ikkßΔmye) mice. In these mice, the ikkß gene has been specifically deleted from myeloid cells, compromising their in vivo IKK/NF-κB-dependent activation. We found that ikkßΔmye mice had significantly reduced neutrophil and macrophage infiltrations after SCI compared to ikkß(+/+) controls. SCI-induced proinflammatory gene expression was also reduced in ikkßΔmye mice. Reduced neuroinflammation in ikkßΔmye mice was accompanied by attenuated neuronal loss and behavioral deficits in motor activity. In addition, the SCI-induced expression of CXC ligand 1 was reduced in ikkßΔmye mice, which may be responsible for the reduced neutrophil infiltration in these mice. Our data demonstrate that IKK-ß-dependent myeloid cell activation potentiates neuroinflammation and neuronal damage after SCI.

Inhibition of inflammation and oxidative stress by Angelica dahuricae radix extract decreases apoptotic cell death and improves functional recovery after spinal cord injury.

Inflammation and oxidative stress play major roles in the pathogenesis after spinal cord injury (SCI). Here, we examined the neuroprotective effects of Angelica dahuricae radix (ADR) extract after SCI. ADR extract significantly decreased the levels of proinflammatory factors such as tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in a lipopolysaccharide (LPS)-activated microglial cell line, BV2 cells. ADR extract also significantly alleviated the level of reactive oxygen species in LPS-activated BV2 cells. To examine the neuroprotective effect of ADR extract after SCI, spinally injured rats were administered ADR extract orally at a dose of 100 mg/kg for 14 days. ADR extract treatment significantly reduced the levels of TNF-α, IL-1ß, IL-6, iNOS, and COX-2. The levels of superoxide anion (O(2·)(-)) and protein nitration were also significantly decreased by ADR extract. In addition, ADR extract inhibited p38 mitogen-activated protein kinase activation and pronerve growth factor expression in microglia after SCI. Furthermore, ADR extract significantly inhibited caspase-3 activation following apoptotic cell death of neurons and oligodendrocytes, thereby improving functional recovery after injury. Thus, our data suggest that ADR extract provides neuroprotection by alleviating inflammation and oxidative stress and can be used as an orally administered therapeutic agent for acute SCI.

Suppression of Transient Receptor Potential Melastatin 7 by Carvacrol Protects against Injured Spinal Cord by Inhibiting Blood-Spinal Cord Barrier Disruption.

When the blood-spinal cord barrier (BSCB) is disrupted after a spinal cord injury (SCI), several pathophysiological cascades occur, including inflammation and apoptotic cell death of neurons and oligodendrocytes, resulting in permanent neurological deficits. Transient receptor potential melastatin 7 (TRPM7) is involved in the pathological processes in many neuronal diseases, including traumatic brain injury, amyotrophic lateral sclerosis, parkinsonism dementia, and Alzheimer's disease. Further, carvacrol (CAR), a TRPM7 inhibitor, is known to protect against SCI by reducing oxidative stress and inhibiting the endothelial nitric oxide synthase pathway. However, the functions of TRPM7 in the regulation of BSCB homeostasis after SCI have not been examined. Here, we demonstrated that TRPM7, a calcium-mediated non-selective divalent cation channel, plays a critical role after SCI in rats. Rats were contused at T9 and given CAR (50 mg/kg) intraperitoneally immediately and 12 h after SCI, and then given the same dose once a day for 7 days. TRPM7 was found to be up-regulated after SCI in both in vitro and in vivo studies, and it was expressed in blood vessels alongside neurons and oligodendrocytes. Additionally, CAR treatment suppressed BSCB disruption by inhibiting the loss of tight junction (TJ) proteins and preserved TJ integrity. CAR also reduced apoptotic cell death and improved functional recovery after SCI by preventing BSCB disruption caused by blood infiltration and inflammatory responses. Based on these findings, we propose that blocking the TRPM7 channel can inhibit the destruction of the BSCB and it is a potential target in therapeutic drug development for use in SCI.

Erratum: Lee et al. Ginseng Extracts, GS-KG9 and GS-E3D, Prevent Blood-Brain Barrier Disruption and Thereby Inhibit Apoptotic Cell Death of Hippocampal Neurons in Streptozotocin-Induced Diabetic Rats. Nutrients 2020, 12, 2383.

The authors have requested that the following changes be made to their paper [...].

Expression of CYLD and NF-kappaB in human cholesteatoma epithelium.

The tumor suppressor CYLD is a deubiquitinating enzyme that inhibits activation of the NF-kappaB, which has key roles in inflammation and apoptosis. We hypothesized that CYLD may regulate the NF-kappaB signaling pathway in cholesteatoma. We conducted immunohistochemistry to examine the expression of CYLD and NF-kappaB in 16 cases of cholesteatoma and paired cases of retroauricular (RA) skin. In cholesteatoma epithelium, activated NF-kappa B expression was significantly higher than in RA skin, whereas CYLD expression was significantly lower in cholesteatoma epithelium than in RA skin (P < .05). Furthermore, a significant inverse correlation was detected between CYLD and activated NF-kappaB expression in cholesteatoma epithelium (r = -0.630). We found that CYLD reduced and activated increased NF-kappaB in cholesteatoma epithelium in comparison to RA skin. The inverse correlation between CYLD and activated NF-kappaB in cholesteatoma may be involved in cholesteatoma epithelial hyperplasia.

Ginseng Extracts, GS-KG9 and GS-E3D, Prevent Blood-Brain Barrier Disruption and Thereby Inhibit Apoptotic Cell Death of Hippocampal Neurons in Streptozotocin-Induced Diabetic Rats.

Type 1 diabetes mellitus is known to be linked to the impairment of blood-brain barrier (BBB) integrity following neuronal cell death. Here, we investigated whether GS-KG9 and GS-E3D, bioactive ginseng extracts from Korean ginseng (Panax ginseng Meyer), inhibit BBB disruption following neuronal death in the hippocampus in streptozotocin-induced diabetic rats showing type 1-like diabetes mellitus. GS-KG9 and GS-E3D (50, 150, or 300 mg/kg, twice a day for 4 weeks) administered orally showed antihyperglycemic activity in a dose-dependent manner and significantly attenuated the increase in BBB permeability and loss of tight junction proteins. GS-KG9 and GS-E3D also inhibited the expression and activation of matrix metalloproteinase-9 and the infiltration of macrophages into the brain parenchyma, especially into the hippocampal region. In addition, microglia and astrocyte activation in the hippocampus and the expression of proinflammatory mediators such as tnf-α, Il-1ß, IL-6, cox-2, and inos were markedly alleviated in GS-KG9 and GS-E3D-treated group. Furthermore, apoptotic cell death of hippocampal neurons, especially in CA1 region, was significantly reduced in GS-KG9 and GS-E3D-treated groups as compared to vehicle control. These results suggest that GS-KG9 and GS-E3D effectively prevent apoptotic cell death of hippocampal neurons by inhibiting BBB disruption and may be a potential therapy for the treatment of diabetic patients.

Calpain-mediated cleavage of Fbxw7 during excitotoxicity.

Neuronal cell death induced by ischemic injury has been attributed to glutamate receptor-mediated excitotoxicity, which is known to be accompanied by Ca2+ overload in the cytoplasm with concomitant activation of calcium-dependent mechanisms. More specifically, the overactivation of calpains, calcium-dependent cysteine proteases, have been associated with neuronal cell death following glutamate treatment. Previously, we observed decreased expression levels of F-box/WD repeat domain-containing protein 7 (Fbxw7) after the hyperactivation of cyclin-dependent kinase 5 (Cdk5) in cortical neurons challenged with glutamate. As determined using in vitro calpain cleavage assays, we demonstrated that the cleavage of Fbxw7 was mediated by activated calpain and attenuated in the presence of the calpain inhibitor, calpeptin. Using the rat middle cerebral artery occlusion model, we confirmed that Fbxw7 was indeed cleaved by activated calpain in the ipsilateral cortex. Based on our data, we hypothesize that the negative regulation of Fbxw7 by calpain may contribute to neuronal cell death and that the preservation of Fbxw7 by the inhibition of calpain, Cdk5, or both composes a novel protective mechanism following excitotoxicity.