Celastrol reverses palmitic acid (PA)-caused TLR4-MD2 activation-dependent insulin resistance via disrupting MD2-related cellular binding to PA.

Elevated plasma statured fatty acids (FFAs) cause TLR4/MD2 activation-dependent inflammation and insulin tolerance, which account for the occurrence and development of obesity. It has been confirmed that statured palmitic acid (PA) (the most abundant FFA) could bind MD2 to cause cellular inflammation. The natural compound celastrol could improve obesity, which is suggested via inhibiting inflammation, yet the detailed mechanism for celastrol is still unclear. As celastrol is reported to directly target MD2, we thought disrupting the binding between FFAs and MD2 might be one of the ways for celastrol to inhibit FFAs-caused inflammation and insulin resistance. In this study, we found evidence to support our hypothesis: celastrol could reverse PA-caused TLR4/MD2 activation-dependent insulin resistance, as determined by glucose-lowering ability, cellular glucose uptake, insulin action-related proteins and TLR4/MD2/NF-κB activation. Bioinformatics and cellular experiments showed that both celastrol and PA could bind MD2, and that celastrol could expel PA from cells. Finally, celastrol could reverse high fat diet caused hyperglycemia and obesity, and liver NF-kB activations. Taking together, we proved that celastrol could reverses PA-caused TLR4-MD2 activation-dependent insulin resistance via disrupting PA binding to MD2.

[Effects of triptolide-medicated serum on secretion function of adrenocortical cells isolated from rats].

OBJECTIVE: To study the effects of triptolide-medicated serum on secretory function of adrenocortical cells isolated from rats. METHODS: Thirty SD rats were randomly divided into control group, prednisone group, and low-, medium- and high-dose triptolide groups. Rats were administered with normal saline, prednisone and low-, medium- and high-dose triptolide respectively by gastrogavage to prepare sera containing drugs. Primary adrenocortical cells were isolated from normal male rats and cultured with sera containing drug for 48 hours. Expression of proliferating cell nuclear antigen (PCNA) was observed by immunohistochemical method and number of PCNA-positive cells was counted. Ultrastructure of adrenocortical cells was observed under a transmission electron microscope. Content of corticosterone in supernatant of adrenocortical cell culture was detected by enzyme-linked immunosorbent assay, and real-time fluorescence quantitative polymerase chain reaction (PCR) was employed to investigate the expression of 3beta-hydroxysteroid dehydrogenase (3beta-HSD) mRNA. RESULTS: As compared with the control group, content of corticosterone in supernatant of adrenocortical cell culture and expression of 3beta-HSD mRNA were significantly increased in the triptolide-treated groups, and the numbers of PCNA-positive cells were increased in the medium- and high-dose triptolide groups, however, they were decreased in the prednisone group. CONCLUSION: Triptolide-medicated serum can increase the secretion of corticosterone in rat adrenocortical cells in vitro.

Tripterine inhibits the expression of adhesion molecules in activated endothelial cells.

Cell adhesion molecules (CAM) expressed by vascular endothelium in response to cytokine stimulation play a key role in leukocyte adhesion to endothelium during the inflammatory response. Tripterine, a chemical compound of the Chinese plant Tripterygium wilfordii Hook f, displays anti-inflammatory properties in several animal models. However, mechanisms of its action are poorly understood. In the present study, we show that in inflammatory conditions, mimicked by tumor necrosis factor alpha (TNF-alpha) stimulation, pretreatment for 6 h with tripterine at nontoxic concentrations of 20-200 nM inhibits the expression of E-selectin, vascular cell adhesion molecule (CAM)-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) in human umbilical vein endothelial cells (HUVEC) in a dose-dependent manner. Tripterine (200 nM) almost completely inhibits expression of VCAM-1 [50% inhibitory concentration (IC50) = 52 nM] and ICAM-1 (IC50 = 51 nM) and 73% of E-selectin (IC50 = 94 nM). This inhibition effect is prominent, compared with that of dexamethasone, ibuprofen, methotrexate, or probucol, which revealed a much weaker inhibition at doses as high as 1 mM. Effects on endothelial CAM of other proinflammatory cytokines, such as interleukin-1beta and interferon-gamma, were also inhibited significantly by tripterine. Moreover, significant inhibition was equally observable in postincubation experiments. In addition, tripterine inhibited adhesion of human monocytes and T lymphocytes to TNF-alpha-stimulated HUVEC. Finally, tripterine inhibited TNF-alpha-driven CAM mRNA transcription and nuclear factor-kappaB nuclear (NF-kappaB) translocation. Hence, we describe a new mechanism of tripterine's anti-inflammatory action obtained at nanomolar concentrations, owing to the negative regulation of cytokine-induced adhesion molecule expression and adhesiveness in human endothelium.

[Tripterine inhibits all-trans retinoic acid-caused adhesion between leukemia cells and endothelial cells].

OBJECTIVE: Increasing of adhesion between leukemia cells and endothelial cells during all-trans retinoic acid (ATRA) treatment plays an important role in retinoic acid syndrome. This work observed the effects of tripterine on this ATRA-caused increasing in adhesion. METHODS: The effects of tripterine on ATRA-induced expressions of adhesive molecules in acute promyelocytic leukemia cell line NB4 and human umbilical vascular endothelial cells (HUVEC) were detected by flow cytometry. The effects of tripterine on adhesion between ATRA-treated NB4 and HUVEC were determined by adhesive assays. RESULTS: ATRA caused remarkable elevation of intercellular adhesion molecule-1 (ICAM-1) in NB4 cells, which could be significantly reduced by tripterine (P<0.01). The expressions of E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and ICAM-1 in HUVEC were elevated by conditioned medium from ATRA-induced NB4 (ATRA-NB4-CM) (P<0.01), and inhibited by tripterine with inhibition rates being 25.3%, 42.4% and 61.0% respectively. ATRA increased the adhesion between NB4 and HUVEC, which was reversed completely by tripterine. CONCLUSION: Tripterine can inhibit ATRA-caused adhesion between leukemia cells and endothelial cells, and it might be a potential agent for treating retinoic acid syndrome.

[An experimental study of effects of active-heating-system for extravehicular spacesuit gloves on working performance].

OBJECTIVE: To observe the effects of active heating system for spacesuit gloves on extravehicular working performance. METHOD: After analyzing the factors with gloves influence on the working performance, the effects of active heating system for gloves were studied experimentally with aspects to fatigue, hand strength, dexterity and tactile sensing. RESULT: 1) Heating-system had not influence to grip; 2) Heating-system had 17% influence to fatigue except specific person; 3) Nut assembly and nipping pin showed that heating-system had little influence to dexterity; 4) Apperceiving shape of object and two-point distance showed heating-system had little influence to tactility. CONCLUSION: The active heating method is rational and has little influence on working performance.

[Advances in the research on targeted preparations of traditional Chinese medicine and natural drugs].

OBJECTIVE: Targeting dosage form is a kind of targeting drug delivery system which can be used to lock drugs aroud the target organs, tissues, cells and obtain more effective treatment for dose concentration, thus reducing the side-effects of such drugs while increasing their effeciveness. Targeting dosage form is the fourth-generation drug dosage form and it is ideal system for administration because it release the theraping drugs in the targeting-site. Particular emphasis was placed on liposome due to it was used as a drug carrier. Meanwhile, the highlights of research were on magnetic and enzyme targeting preparations. In addition, oral colon targeting drug delivery system, drugs were carried to ileocecum and release to get local and whole effect, is also an important part of targeting dosage form. The study on traditional chinese medicine (TCM) targeting dosage form is still at beginning stage in China. At present, most of study on TCM and natural products targeting drugs were focus on simple effective component and merely on TCM effective positions in relative with the difficult for determing their quality standard and procedure of preparing. It is the kernel item for TCM modernization and the key for TCM internationalization to develop new dosage form and new technology of TCM. There is a need in collaboration with multiple discipline. It will be a important research subject to develop TCM targeting preparation in the near future. TCM targeting dosage form can be classified into liposome, nanoparticles, multiple emulsion etc according to the difference of carrier and oral, rectal, colonic, nasal, dermal, ocular system on a basis of administration and so on. This paper made a summary on TCM and natural products targeting dosage form according to different targeting positions and introduce the procedure of preparing compared with the effect in vivo and manifest that TCM and natural products targeting dosage form will have good exploit prospect.