Combination of betulinic acid and chidamide synergistically inhibits Epstein-Barr virus replication through over-generation of reactive oxygen species.

Epstein-Barr virus (EBV) has widely infected more than 90% of human populations. Currently, there is no efficient way to remove the virus because the EBV carriers are usually in a latent stage that allows them to escape the immune system and common antiviral drugs. In the effort to develop an efficient strategy for the removal of the EBV virus, we have shown that betulinic acid (BA) slightly suppresses EBV replication through SOD2 suppression with subsequent reactive oxygen species (ROS) generation and DNA damage in EBV-transformed LCL (lymphoblastoid cell line) cells. Chidamide (CDM, CS055), a novel histone deacetylase inhibitor (HDACi), could significantly switch EBV from the latent stage to the lytic stage with increased gene expression of BZLF1 and BMRF1, but has a small effect on EBV replication due to the suppression effect of CDM-mediated ROS generation. Interestingly, a combination of BA and CDM synergistically inhibits EBV replication with ROS over-generation and subsequent DNA damage and apoptosis. Overexpression of SOD2 diminishes this effect, while SOD2 knockdown mimics this effect. An in vivo xenograft tumor development study with the tail vein injection of EBV-transformed LCL cells in nude mice proves that the combination of BA and CDM synergistically increases superoxide anion release in tumor tissues and suppresses EBV replication and tumor growth, and significantly prolongs mouse survival. We conclude that the combination of BA and CDM could be an efficient strategy for clinical EBV removal.

SIRT1-mediated ERß suppression in the endothelium contributes to vascular aging.

SIRT1 has many important molecular functions in aging, and the estrogen receptors (ERs) have a vasculoprotective effect, although the detailed mechanism for the roles of SIRT1 and ERs in vascular aging remains unclear. We found that ERß expression in the endothelium was reduced in aging mice, and the expression of ERα and SIRT1 did not change, while SIRT1 activity declined. Further investigation showed that the ERß expression was regulated by SIRT1 through complexes of SIRT1-PPARγ/RXR-p300 that bind to a PPRE (PPAR response element) site on the ERß promoter, and the declined SIRT1 function in aging mice was due to compromised phosphorylation at S154. A single-mutant SIRT1-C152(D) restored the reduced ERß expression in the endothelium with minimized reactive oxygen species generation and DNA damage and increased mitochondrial function and fatty acid metabolism. In high-fat diet aging mice, the endothelium-specific delivery of ERß or SIRT1-C152(D) on the vascular wall reduced the circulating lipids with ameliorated vascular damage, including the restored vessel tension and blood pressure. We conclude that SIRT1-mediated ERß suppression in the endothelium contributes to vascular aging, and the modulation of SIRT1 phosphorylation through a single-mutant SIRT1-C152(D) restores this effect.

Estradiol mediates vasculoprotection via ERRα-dependent regulation of lipid and ROS metabolism in the endothelium.

The estrogen-mediated vasculoprotective effect has been widely reported in many animal studies, although the clinical trials are controversial and the detailed mechanisms remain unclear. In this study, we focused on the molecular mechanism and consequence of 17ß-estradiol (E2)-induced ERRα (estrogen-related receptor alpha) expression in endothelium and its potential beneficial effects on vascular function. The human aorta endothelial cells were used to identify the detailed molecular mechanism and consequences for E2-induced ERRα expression through estrogen receptors (ER), where ERα responses E2-induced ERRα activation, and ERß responses basal ERRα expression. E2-induced ERRα expression increases fatty acid uptake/oxidation with increased mitochondrial replication, ATP generation and attenuated reactive oxygen species (ROS) formation. We have obtained further in vivo proof from high-fat diet mice that the lentivirus-carried endothelium-specific delivery of ERRα expression on the vascular wall normalizes E2 deficiency-induced increased plasma lipids with ameliorated vascular damage. ERRα knockdown worsens the problem, and the E2 could only partly restore this effect. This is the first time we report the detailed mechanism with direct evidence that E2-induced ERRα expression modulates the fatty acid metabolism and reduces the circulating lipids through endothelium. We conclude that E2-induced ERRα expression in endothelium plays an important role for the E2-induced vasculoprotective effect.

Brief communication: Y-chromosome haplogroup analysis indicates that Chinese Tuvans share distinctive affinity with Siberian Tuvans.

Tuvans are mainly distributed in Siberia (the Republic of Tuva), Mongolia, and China. The genetic origin of Chinese Tuvans remains controversial. The Tuvans in China were classified as Mongolians in the early 1950s by the National Ethnic Affairs Commission of China, but they defined themselves as a separate group. To resolve this dispute and determine their genetic relationships with the peoples in Central Asia, we randomly selected 150 male subjects from the Tuvans in the Altai region of Xinjiang Uygur Autonomous Region in China. Fourteen Y chromosomal markers were genotyped using the RFLP method or direct sequencing. These haplogroup data were combined with public data for 15 populations in South Siberia and Central Asia. Tuvans in both China and the Republic of Tuva had the highest frequencies of haplogroups K-M9 and Q-M242. Principal component analysis demonstrated that the Tuvans in China were of a distinct cluster, separated from their neighbors, the Mongolians and Kazakhs, which finding was consistent with the Analysis of Molecular Variances. Further population tree analysis revealed that Tuvans were on a far-separated cluster from their neighbors. Based on these results, we propose that the Tuvans (in both China and the Republic of Tuva) constitute a group distinct from Mongolians and from other Central Asia populations. However, the genetic results might be the consequence of some evolutionary forces like genetic drift and founder effect, and do not necessarily reflect their ultimate origin.