• Biomolecules & Therapeutics
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• v.18 no.3
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• pp.316-320
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• 2010

Pruritus is one of major symptoms in atopic dermatis. The pathophysiological mechanism of pruritus is unclear. The search for pruritogen is important in elucidating the pathophysiological mechanism of pruritus in atopic dermatitis. Glucosylsphingosine (Gsp) is upregulated in the strateum corneum of atopic dermatitis patients. We investigated to determine whether Gsp induces itch-scratch responses (ISRs) in mice. Intradermal administration of Gsp induces ISRs. Gsp dose-dependently induced scratching response at 50-500 nmol/site range. Pretreatment with naltrexone, an opioid $\mu$ receptor antagonist, and capsaicin, a TrpV1 receptor agonist, inhibited Gsp-induced ISRs. Additionally, Gsp-induced ISRs were also suppressed by cyproheptadine, an antagonist of serotonin receptor. These findings suggest that Gsp-induced scratching might be at least partly mediated by capsaicin-sensitive primary afferents, and the opioids receptor systems might be involved in transmission of itch signaling in the central nervous system. Furthermore, our findings suggest that Gsp-induced ISRs may be attributable to the serotonin-mediated pathways and Gsp is not any more one of byproducts of abnormal skin barrier but can lead to induce pruritus, one of typical symptoms of atopic dermatitis.

• Biomolecules & Therapeutics
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• v.25 no.5
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• pp.497-503
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• 2017

Recent reports claimed that glucosylsphingosine (GS) is highly accumulated and specifically evoking itch-scratch responses in the skins of atopic dermatitis (AD) patients. However, it was unclear how GS can trigger itch-scratch responses, since there were no known molecular singling pathways revealed yet. In the present study, it was verified for the first time that GS can activate mouse serotonin receptor 2a (mHtr2a) and 2b (mHtr2b), but not 2c (mHtr2c) that are expressed in HEK293T cells. Specifically, effects of GS on all mouse serotonin receptor 2 subfamily were evaluated by calcium imaging techniques. The GS-induced intracellular calcium increase was dose-dependent, and antagonists such as ketanserin (Htr2a antagonist) and RS-127445 (Htr2b antagonist) significantly blocked the GS-induced responses. Moreover, the proposed GS-induced responses appear to be mediated by phospholipase C (PLC), since pretreatment of a PLC inhibitor U-73122 abolished the GS-induced responses. Additionally, the GS-induced calcium influx is probably mediated by endogenous TRPC ion channels in HEK293T cells, since pretreatment of SKF-96365, an inhibitor for TRPC, significantly suppressed GS-induced response. In conclusion, the present study revealed for the first time that GS can stimulate mHtr2a and mHtr2b to induce calcium influx, by utilizing PLC-dependent pathway afterwards. Considering that GS is regarded as a pruritogen in AD, the present study implicates a novel GS-induced itch signaling pathway.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.20 no.1
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• pp.1-13
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• 2020

Purpose: Gaucher disease (GD), which is the most prevalent lysosomal storage disorder worldwide, is caused by mutations in the glucocerebrosidase gene (GBA). GD is divided into three clinical subtypes based on the appearance of neurological symptoms. Type 1 GD is a chronic non-neuronopathic disease, and types 2 and 3 are acute neuronopathic and chronic neuronopathic forms, respectively. Neuronopathic GD types 2 and 3 are characterized by increased levels of glucosylceramide (GlcCer) and glucosylsphingosine (GlcSph) in the brain, leading to massive loss of neurons. Methods: DNA damage and subsequent apoptosis of H4 cells were observed following neuroglioma H4 cell culture with GlcCer or GlcSph. Neuronal cell apoptosis was more prominent upon treatment with GlcSph. Results: When H4 cells were treated with GlcSph in the presence of tubacin, a histone deacetylase 6 inhibitor (HDAC6i), attenuation of both DNA damage and a reduction in the protein expression levels of GlcSph-induced apoptosis-associated factors were observed. Conclusion: These findings indicated that GlcSph played a prominent role in the pathogenesis of neuronopathic GD by inducing apoptosis, and that HDAC6i could be considered a therapeutic candidate for the treatment of neuronopathic GD.

• Journal of mucopolysaccharidosis and rare diseases
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• v.5 no.1
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• pp.1-7
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• 2021

Gaucher disease (GD, OMIM #230800 OMIM#230800) is a rare, autosomal recessive inherited metabolic disorder caused by mutation in GBA1 encoding the lysosomal enzyme, glucocerebrosidase. The deficiency of glucocerebrosidase leads to an accumulation of its substrate, glucosylceramide in macrophages of various tissues. Common clinical manifestations include cytopenia, splenomegaly, hepatomegaly, and bone lesions. The phenotype of GD is classified into three clinical categories: Type 1 (non-neuronopathic) is characterized by involvements on the viscera, whereas types 2 and 3 (neuronopathic) are associated with not only visceral symptoms but also neurological impairment, either severe in type 2 or variable in type 3. A diagnosis of GD can be confirmed by demonstrating the deficiency of acid glucocerebrosidase activity in leukocytes. Mutations in the GBA1 should be identified as they may be of prognostic value in some cases. Biomarkers including Chitotriosidase, CCL18, and glucosylsphingosine (lyso-GL1) are useful in diagnosis and treatment monitoring. Currently available disease-specific treatment in Korea consists of intravenous enzyme replacement therapy and substrate reduction therapy. For enhancing long-term prognosis, the onset of Parkinson's disease and Lewy body dementia, or the occurrence of a blood disease or cancer (hepatocellular carcinoma) should be monitored in older patients. The development of new strategies that can modify the neurological phenotype are expected, especially in Asia including Korea, where the prevalence of neuronopathic GD is relatively higher than that in western countries.