• Preventive Nutrition and Food Science
• /
• v.5 no.4
• /
• pp.184-188
• /
• 2000

HMG-CoA reductase is th rate-limiting enzyme of cholesterol biosynthesis. As intracellular levels of cholesterol should be regulated elaborately in response to external stimuli an internal needs, the expression of the HMG-CoA reductase gene is regulated intricately at several different levels from transcription to post-translational modification. In this study, we investigated the regulatory mechanism of HMG-CoA reductase gene expression at the post-transcriptional/pre-translational levels in a baby hamster kidney cell line, C100. when 25-hydroxycholesterol was added to cells cultured in medium containing 5% delipidized fetal bovine serum and 25$\mu$M lovastatin, the levels of HMG-CoA reductase mRNA decreased rapidly, which seemed to be due to the increased degradation of reductase mRNA. These suppressive effects of 25-hydroxycholesterol on MG-CoA reductase mRNA levels were blocked by a translation inhibitor, cycloheximide. Similarly, actinomycin D and 5,6-dichloro-1-$\beta$-D-ribofuranosylbenzimidazole, transcription inhibitors, blocked the 25-hydroxycholesterol-mediated degradation of HMG-CoA reductase mRNA. These results indicate that new protein/RNA synthesis is required for the degradation of HMG-CoA reductase mRNA. In addition, data from the transfection experiments shows that cis-acting determinants, regulating the stability of reductase mRNA, were scattered in the sequence corresponding to 1766-4313 based on the sequence of Syrian hamster HMG-CoA reductase cDNA. Our data suggests that sterol-mediated destabilization of reductase mRNA might be one of the important regulatory mechanism of HMG-CoA reductase gene expression.

• Natural Product Sciences
• /
• v.25 no.1
• /
• pp.49-58
• /
• 2019

Eleven steroid hormones (SHs: androstene-3,17-dione, estrone, ${\beta}$-estradiol, ${\alpha}$-estradiol, testosterone, dehydroepiandrosterone, $17{\acute{a}}$-hydroxyprogesterone, medroxyprogesterone, megestrol acetate, progesterone, and androsterone) were detected from New Zealand deer (Cervus elaphus var. scoticus) velvet antler (NZA, 鹿茸 ). A method for the quantification of eleven SHs was established by using ultraperformance liquid chromatography (UPLC)-MS/MS. The linearities ($R^2$ > 0.991), limits of quantification (LOQ values, 0.3 ng/mL to 23.1 ng/mL), intraday and interday precisions (relative standard deviation: RSD < 2.43%), and recovery rates (97.3% to 104.6%) for all eleven SHs were determined. In addition, a method for the quantification of three 7-oxycholesterols (7-O-CSs: 7-ketocholesterol, $7{\alpha}$-hydroxycholesterol, and $7{\beta}$-hydroxycholesterol) in the NZA was established by using an HPLC-photodiode array (PDA) method. The linearities ($R^2$ > 0.999), LOQ values (30 ng/mL to 350 ng/mL), intraday and interday precisions (RSD < 1.93%), and recovery rates (97.2% to 103.5%) for the three 7-O-CSs were determined. These quantitative methods are accurate, precise, and reproducible. As a result, it is suggested that the five steroid compounds of androstene-3,17-dione, androsterone, 7-ketocholesterol, $7{\alpha}$-hydroxycholesterol, and $7{\beta}$-hydroxycholesterol could be marker steroids of NZA. These methods can be applied to quantify or standardize the marker steroids present in NZA.

• The Korean Journal of Physiology and Pharmacology
• /
• v.28 no.2
• /
• pp.107-112
• /
• 2024

27-Hydroxycholesterol (27OHChol), a prominent cholesterol metabolite present in the bloodstream and peripheral tissues, is a kind of immune oxysterol that elicits immune response. Recent research indicates the involvement of 27OHChol in metabolic inflammation (meta-inflammation) characterized by chronic responses associated with metabolic irregularities. 27OHChol activates monocytic cells such that they secrete pro-inflammatory cytokines and chemokines, and increase the expression of cell surface molecules such as pattern-recognition receptors that play key roles in immune cell-cell communication and sensing metabolism-associated danger signals. Levels of 27OHChol increase when cholesterol metabolism is disrupted, and the resulting inflammatory responses can contribute to the development and complications of metabolic syndrome, including obesity, insulin resistance, and cardiovascular diseases. Since 27OHChol can induce chronic immune response by activating monocyte-macrophage lineage cells that play a crucial role in meta-inflammation, it is essential to understand the 27OHChol-induced inflammatory responses to unravel the roles and mechanisms of action of this cholesterol metabolite in chronic metabolic disorders.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.2
• /
• pp.251-255
• /
• 2008

Cholesterol and cholesterol oxide products (COPs) of Gulbi (Pseudosciaena manchurica) processed and stored at different salting times of 5 hours and 5 days were analyzed. The content of cholesterol was $133.4{\pm}5.20\;mg/100\;g$ in the fresh sample. Cholesterol content was decreased during salting and storage; its contents were $130.3{\pm}2.95\;mg/100\;g$ and $87.2{\pm}3.49\;mg/100\;g$ in 5 hours and 5 days salting samples, respectively. The content of 7-ketocholesterol in 5 hours and 5 days salting samples were $75.2{\pm}2.70\;{\mu}g/100\;g$ and $82.4{\pm}3.30\;{\mu}g/100\;g$. The 7-ketocholesterol content of salting sample for 5 hours had no significantly difference for 2 days sun drying, but it was dramatically increased during 5 days sun drying and then increased during storage days. $7{\alpha}-$ and $7{\beta}-hydroxycholesterol$ were not detected in fresh sample, but increased during Gulbi processing and storage. The $7{\alpha}-hydroxycholesterol$ was increased during Gulbi processing and storage and a higher level of $658.1{\pm}6.20\;{\mu}g/100\;g$ was detected in 5 hours salting sample than in 5 days salting sample after 21 days storage. The $7{\beta}-hydroxycholesterol$ also showed similar tendency with $7{\alpha}-hydroxycholesterol$; it was largely increased between 7 and 14 days storage in 5 days salting sample.

• YAKHAK HOEJI
• /
• v.12 no.3_4
• /
• pp.76-84
• /
• 1968

When 19-hydroxycholesterol acetate was added into CSD-10 in Nutrient Broth or in a mineral salts medium consisting of KH$_{2}$PO$_{4}$(0.1%), $K_{2}$HPO$_{4}$(0.1%), NH$_{4}$NO$_{3}$(0.1%), MgSO$_{4}$(0.02%), CaCl$_{2}$(0.002%), and FeCl$_{3}$(0.005%), a substantial amount of 19-hydroxyandrost-4-ene-3,17-dione was accumulated prior to accumulation of estrone. From this result and all of previous works, a tentative degradation pathway of 19-hydroxycholesterol acetate to estrone by CSD-10 was derived. 19-hydroxyandrost-4-ene-3,17-dione seems to be an attractive intermediate for the synthesis of 19-norsteroids.

• Journal of Microbiology
• /
• v.41 no.4
• /
• pp.284-288
• /
• 2003

Bacillus subtilis SFF34 degrading cholesterol was applied to reduce residual cholesterol content in fermented flatfish. When the bacterial cells were inoculated as a start culture, a maximal level (1.7 U/g) of cholesterol oxidase was obtained after 10 days, which was two times higher than that (0.8 U/g) without inoculation. Residual cholesterol contents with and without inoculation of the cells were 0.5 mg/g and 0.8 mg/g after 12 days of fermentation, respectively. Cholesterol derivatives including cholesterol- 5${\alpha},\;6{\alpha}$-epoxide, 4-cholesten-3-one and 7${\beta}$-hydroxycholesterol were detected in raw flatfish as well as fermented flatfish. Campesterol and 25-hydroxycholesterol were detected only after fermentation. However, no significant differences in their contents were observed regardless of inoculation.

• The Korean Journal of Physiology and Pharmacology
• /
• v.24 no.3
• /
• pp.249-257
• /
• 2020

The aim of the present study was to investigate the pathophysiological etiology of osteoarthritis that is mediated by the apoptosis of chondrocytes exposed to 25-hydroxycholesterol (25-HC), an oxysterol synthesized by the expression of cholesterol-25-hydroxylase (CH25H) under inflammatory conditions. Interleukin-1β induced the apoptosis of chondrocytes in a dose- dependent manner. Furthermore, the production of 25-HC increased in the chondrocytes treated with interleukin-1β through the expression of CH25H. 25-HC decreased the viability of chondrocytes. Chondrocytes with condensed nucleus and apoptotic populations increased by 25-HC. Moreover, the activity and expression of caspase-3 were increased by the death ligand-mediated extrinsic and mitochondria-dependent intrinsic apoptotic pathways in the chondrocytes treated with 25-HC. Finally, 25-HC induced not only caspase-dependent apoptosis, but also induced proteoglycan loss in articular cartilage ex vivo cultured rat knee joints. These data indicate that 25-HC may act as a metabolic pathophysiological factor in osteoarthritis that is mediated by progressive chondrocyte death in the articular cartilage with inflammatory condition.

• The Korean Journal of Physiology and Pharmacology
• /
• v.21 no.3
• /
• pp.301-308
• /
• 2017

27-Hydroxycholesterol induces differentiation of monocytic cells into mature dendritic cells, mDCs. In the current study we sought to determine roles of the PI3K and the ERK pathways in the 27OHChol-induced differentiation. Up-regulation of mDC-specific markers like CD80, CD83 and CD88 induced by stimulation with 27OHChol was significantly reduced in the presence of LY294002, an inhibitor of PI3K, and U0126, an inhibitor of ERK. Surface expression of MHC class I and II molecules elevated by 27OHChol was decreased to basal levels in the presence of the inhibitors. Treatment with LY294002 or U0126 resulted in recovery of endocytic activity which was reduced by 27OHChol. CD197 expression and cell adherence enhanced by 27OHChol were attenuated in the presence of the inhibitors. Transcription and surface expression of CD molecules involved in atherosclerosis such as CD105, CD137 and CD166 were also significantly decreased by treatment with LY294002 and U0126. These results mean that the PI3K and the ERK signaling pathways are necessary for differentiation of monocytic cells into mDCs and involved in over-expression of atherosclerosis-associated molecules in response to 27OHChol.

• The Korean Journal of Physiology and Pharmacology
• /
• v.18 no.6
• /
• pp.475-480
• /
• 2014

We investigated the question of whether cholesterol catabolite can influence expression of inflammatory cytokines via Toll-like receptors (TLR) in monocytic cells. Treatment of THP-1 monocytic cells with 27-hydroxycholesterol (27OHChol) resulted in induction of gene transcription of TLR6 and elevated level of cell surface TLR6. Addition of FSL-1, a TLR6 agonist, to 27OHChol-treated cells resulted in transcription of the $IL-1{\alpha}$ gene and enhanced secretion of the corresponding gene product. However, cholesterol did not affect TLR6 expression, and addition of FSL-1 to cholesterol-treated cells did not induce expression of $IL-1{\alpha}$. Using pharmacological inhibitors, we investigated molecular mechanisms underlying the expression of TLR6 and $IL-1{\alpha}$. Treatment with Akt inhibitor IV or U0126 resulted in significantly attenuated expression of TLR6 and $IL-1{\alpha}$ induced by 27OHChol and 27OHChol plus FSL-1, respectively. In addition, treatment with LY294002, SB202190, or SP600125 resulted in significantly attenuated secretion of $IL-1{\alpha}$. These results indicate that 27OHChol can induce inflammation by augmentation of TLR6-mediated production of $IL-1{\alpha}$ in monocytic cells via multiple signaling pathways.

• Natural Product Sciences
• /
• v.23 no.4
• /
• pp.239-246
• /
• 2017

27-Hydroxycholesterol (27OHChol) has been reported to induce differentiation of monocytic cells into a mature dendritic cell phenotype. We examined the effect of methanol extract of Nardostachys chinensis (Nard) on 27OHChol-induced differentiation using THP-1, a human monocytic cell line. Treatment of monocytic cells with methanol extract of Nard resulted in decreased transcription and surface expression of CD80, CD83, and CD88 elevated by 27OHChol in a dose-dependent manner. Surface levels of MHC class I and II molecules elevated by 27OHChol were also reduced to basal levels by treatment with the Nard extract. Decreased endocytosis activity caused by 27OHChol was recovered by treatment with the Nard extract. CD197 expression and cell attachment were attenuated by the Nard extract. In addition, levels of transcription and surface expression of CD molecules involved in atherosclerosis, such as CD105, CD137, and CD166 upregulated by 27OHChol were significantly decreased by treatment with methanol extract of Nard. These results indicate that methanol extract of Nard down-regulates 27OHChol-induced differentiation of monocytic cells into a mature dendritic cell phenotype and expression of CD molecules associated with atherosclerosis. The current study suggests that biological activity of oxygenated cholesterol derivatives can be inhibited by herbal medication.