Different susceptibility of human immunodeficiency virus type 1 to Env gp41-derived synthetic peptides corresponding to the C-terminal heptad repeat region

Chinese medicine CGA formula ameliorates liver fibrosis induced by carbon tetrachloride involving inhibition of hepatic apoptosis in rats

ETHNOPHARMACOLOGICAL REVELVANCE

CGA consisting of Cordyceps sinensis mycelia polysaccharide, gypenosides and amygdalin, was demonstrated to be the effective components formula in Fuzheng Huayu (FZHY) capsule, a traditional Chinese medicine approved by China food and drug administration for treatment of liver fibrosis and to inhibit transforming growth factor-β1 (TGF-β1) signaling, previously.

AIM OF THE STUDY

To evaluate the effects of CGA on hepatic apoptosis in liver fibrosis induced by carbon tetrachloride (CCl₄).

MATERIALS AND METHODS

The hepatic injury and histology was detected by serum biomarker assay and hematoxylin-eosin staining. The hepatic collagen was illustrated by Sirius red staining and hydroxyproline (Hyp) concentration. The hepatic stellate cells (HSCs) activation and hepatic apoptosis was visualized by immunohistochemical analysis of α-smooth muscle actin (α-SMA) and terminal deoxynucleotidyl transferase-mediated dUPT nick-end labeling (TUNEL) assay respectively. The protein expression of collagen type I (Col-I), α-SMA, TGF-β1, Fas, tumor necrosis factor receptor 1 (TNF-R1), cleaved-caspase-8, cleaved-caspase-10, cleaved-caspase-9, cleaved-caspase-3, mitochondrial Bcl-2, Bcl-2 associated X protein (Bax), Bcl-2 homologous antagonist/killer (Bak), cytochrome C and cytoplasmic cytochrome C was detected by western-blot.

RESULTS

CGA or FZHY ameliorated liver histological changes, decreasing serum alanine aminotransferase, aspartate aminotransferase, hepatic Hyp, TUNEL positive-stained area, and down-regulated the protein expression of α-SMA, TGF-β1, Col-I, Fas, TNF-R1, cleaved-caspase-8, cleaved-caspase-10, cleaved-caspase-9, and cleaved-caspase-3, mitochondrial Bax, Bak, and cytoplasmic cytochrome C, while restored the expression of mitochondrial Bcl-2 and cytochrome C.

CONCLUSION

CGA formula ameliorates liver fibrosis induced by CCl₄, which is correlated to its inhibition on hepatic apoptosis.

Anti-fibrotic effect of Cordyceps sinensis polysaccharide: Inhibiting HSC activation, TGF-β1/Smad signalling, MMPs and TIMPs

Cordyceps sinensis has been used to treat liver disease in traditional Chinese medicine for thousands of years. Polysaccharide extracted from cultured Cordyceps sinensis mycelia (CS-PS) is the major active components of cordyceps sinensis with anti-liver injury effects. In the present study, the effects of CS-PS on hepatic stellate cell (HSC) activation, transforming growth factor-β1 (TGF-β1)/Smad pathway, as well as matrix metalloproteinase (MMP) 2, MMP9 and tissue inhibitor of metalloproteinase (TIMP) 1, TIMP2, were investigated in liver fibrosis in rats induced by carbon tetrachloride (CCl4). Colchicine was used as a positive control. The effect of CS-PS inhibition liver injury and fibrosis was confirmed by decreasing serum alanine aminotransferase, aspartate aminotransferase, total bilirubin, hepatic hydroxyproline and increasing serum albumin, as well as alleviation of histological changes, which was comparable to that of colchicine. With CS-PS treatment, hepatic α-smooth muscle actin, TGF-β1, TGF-β1 receptor (TβR)-I, TβR-II, p-Smad2, p-Smad3 and TIMP2 proteins expression were down-regulated comparing to that in CCl4 group. The activities of MMP2 and MMP9 in liver tissue were also inhibited in CS-PS-treated group. It is indicated that the effects of CS-PS anti-liver fibrosis are probably associated with the inhibition on HSC activation, TGF-β1/Smads signalling pathway, as well as MMP2, MMP9 activity and TIMP2 expression.

L565M mutation in HIV-1 glycoprotein 41 stabilizes the coiled-coil structure

N-terminal and C-terminal heptad repeats (NHR and CHR) of HIV type 1 (HIV-1) glycoprotein 41 are known to be regions directly related to cell fusion during virus attack, and their complex core constructs a coiled-coil structure in the fusion process. In our recent studies, MT-4/17-3-6, a strain of HIV-1, showed the strong resistance to peptide fusion inhibitors compared with other strains such as MT-4/LAI, L-2 and CU98-26, and had a distinctive L565M mutation in the central region of NHR. To investigate the relationship between the mutation and resistance, we performed a molecular modeling of the coiled-coil of MT-4/17-3-6 by using energy minimization and molecular dynamics simulation based on the MT-4/LAI X-ray structure. As a result, we found that H564 in the NHR was pushed to the outer side by this mutation, and three hydrogen bond bridges of Y638-H564-E560-Q650 could be formed, enclosing the coiled-coil. The binding of peptide inhibitors would be disturbed by the structural stabilization of these bridges in MT-4/17-3-6.