SUMMARY Imbalances in glucose and energy homeostasis are at the core of the worldwide epidemic of obesity and diabetes. Here, we illustrate an important role of the TGF-β/Smad3 signaling pathway in regulating glucose and energy homeostasis. Smad3 deficient mice are protected from diet-induced obesity and diabetes. Interestingly, the metabolic protection is accompanied by Smad3−/− white adipose tissue acquiring the bioenergetic and gene expression profile of brown fat/skeletal muscle. Smad3−/− adipocytes demonstrate a marked increase in mitochondrial biogenesis, with a corresponding increase in basal respiration, and Smad3 acts as a repressor of PGC-1α expression. We observe significant correlation between TGF-β1 levels and adiposity in rodents and humans. Further, systemic blockade of TGF-β1 signaling protects mice from obesity, diabetes and hepatic steatosis. Together, these results demonstrate that TGF-β signaling regulates glucose tolerance and energy homeostasis and suggest that modulation of TGF-β1 activity might be an effective treatment strategy for obesity and diabetes.

The ubiquitin-proteasome system has recently emerged as a major target for drug development in cancer therapy. The proteasome inhibitor bortezomib has clinical activity in multiple myeloma and mantle cell lymphoma. Here we report that Eeyarestatin I (EerI), a chemical inhibitor that blocks endoplasmic reticulum (ER)-associated protein degradation, has antitumor and biologic activities similar to bortezomib and can synergize with bortezomib. Like bortezomib, EerI-induced cytotoxicity requires the up-regulation of the Bcl-2 homology3 (BH3)-only pro-apoptotic protein NOXA. We further demonstrate that both EerI and bortezomib activate NOXA via an unanticipated mechanism that requires cooperation between two processes. First, these agents elicit an integrated stress response program at the ER to activate the CREB/ATF transcription factors ATF3 and ATF4. We show that ATF3 and ATF4 form a complex capable of binding to the NOXA promoter, which is required for NOXA activation. Second, EerI and bortezomib also block ubiquitination of histone H2A to relieve its inhibition on NOXA transcription. Our results identify a class of anticancer agents that integrate ER stress response with an epigenetic mechanism to induce cell death.bortezomib ͉ cancer therapy ͉ ER stress/UPR ͉ histone H2A ͉ ubiquitin T he ubiquitin proteasome system (UPS) constitutes a major disposal pathway for misfolded proteins at the endoplasmic reticulum (ER) and therefore promotes protein homeostasis. It has been shown that misfolded ER proteins are exported from the ER into the cytosol by a process termed ER-associated protein degradation (ERAD) or retrotranslocation (1, 2). This process requires a cytosolic ATPase named p97, which acts as a ''dislocase'' to extract misfolded proteins from the ER membranes once substrates have undergone polyubiquitination. p97 subsequently hands substrates over to the proteasome for degradation (3). Defects in ERAD cause accumulation of misfolded proteins in the ER and thus trigger ER stress (also called Unfolded Protein Response, UPR).The functional integrity of the UPS is also essential for the survival of cancer cells because their uncontrolled proliferation requires proteasome mediated degradation of many cell cycle factors (4). Accordingly, the proteasome inhibitor bortezomib (Velcade TM ) has cytotoxic activities against a broad range of cancer cell lines and is now used in the clinic to treat multiple myeloma and mantle cell lymphoma (MCL) (5). The precise mechanism by which bortezomib induces cytotoxicity in cancer cells remains elusive. Recent studies showed that the induction of the Bcl-2 homology3 (BH3)-only pro-apoptotic protein NOXA plays an important role (6-12). On a separate note, several other studies suggested that ER stress elicited by bortezomib may account for its cytotoxicity (8, 13). It is currently unclear whether NOXA activation and ER stress are mechanistically connected or independently triggered by bortezomib as a result of stabilization of distinct proteasomal substrates. In addition, although...

The meta-analysis shows that the use of tranexamic acid for patients undergoing total knee arthroplasty is effective and safe for the reduction of blood loss.

BACKGROUND & AIMS Polymorphisms in the IL28B gene have been associated with clearance of hepatitis C virus (HCV), indicating a role for type III interferons (IFNs) in HCV infection. Little is known about the function of type III IFNs in intrinsic antiviral innate immunity. METHODS We used in vivo and in vitro models to characterize the role of the type III IFNs in HCV infection and analyzed gene expression in liver biopsy samples from HCV-infected chimpanzees and patients. Messenger RNA and protein expression were studied in HCV-infected hepatoma cell lines and primary human hepatocytes. RESULTS HCV infection of primary human hepatocytes induced production of chemokines and type III IFNs, including interleukin (IL)-28, and led to expression of IFN-stimulated genes (ISGs). Chimpanzees infected with HCV showed rapid induction of hepatic type III IFN, associated with up-regulation of ISGs and minimal induction of type I IFNs. In liver biopsy specimens from HCV-infected patients, hepatic expression of IL-28 correlated with levels of ISGs but not of type I IFNs. HCV infection produced extensive changes with gene expression in addition to ISGs in primary human hepatocytes. The induction of type III IFNs is regulated by IFN regulatory factor 3 and nuclear factor κB. Type III IFNs up-regulate ISGs with a different kinetic profile than type 1 IFNs and induce a distinct set of genes, which might account for their functional differences. CONCLUSIONS HCV infection results predominantly in induction of type III IFNs in livers of humans and chimpanzees; the level of induction correlates with hepatic levels of ISGs. These findings might account for the association among IL-28, level of ISGs, and recovery from HCV infection and provide a therapeutic strategy for patients who do not respond to IFN therapy.

Summary Germline mutations of BRCA1 predispose women to breast and ovarian cancers. However, the downstream mediators of BRCA1 function in tumor suppression remain elusive. We found that human BRCA1-associated breast cancers have lower levels of SIRT1 than their normal controls. We further demonstrated that mammary tumors from BRCA1 mutant mice have low levels of SIRT1 and high levels of Survivin, which is reversed by induced expression of BRCA1. BRCA1 binds to the SIRT1 promoter and increases SIRT1 expression, which in turn inhibits Survivin by changing the epigenetic modification of histone H3. Absence of SIRT1 blocks the regulation of Survivin by BRCA1. Furthermore, we demonstrated that activation of SIRT1 and inhibition of Survivin expression by resveratrol elicit a more profound inhibitory effect on BRCA1-mutant cancer cells than on BRCA1-wild type cancer cells both in vitro and in vivo. These findings suggest that resveratrol treatment serves as an excellent strategy for targeted therapy for BRCA1-associated breast cancer.

The reasons for hepatitis C treatment failure remain unknown but may be related to different host responses to therapy. In this study, we compared hepatic gene expression in patients prior to and during peginterferon and ribavirin therapy. In the on-treatment group, patients received either ribavirin for 72 hours prior to peginterferon alpha-2a injection or peginterferon alpha-2a for 24 hours, prior to biopsy. The patients were grouped into rapid responders (RRs) with a greater than 2-log drop and slow responders (SRs) with a less than 2-log drop in hepatitis C virus RNA by week 4. Pretreatment biopsy specimens were obtained from a matched control group. The pretreatment patients were grouped as RRs or SRs on the basis of the subsequent treatment response. Gene expression profiling was performed with Affymetrix microarray technology. Known interferon-stimulated genes (ISGs) were induced in treated patients. In the pretreatment group, future SRs had higher pretreatment ISG expression than RRs. On treatment, RRs and SRs had similar absolute ISG expression, but when it was corrected for the baseline expression with the pretreatment group, RRs showed a greater fold change in ISGs, whereas SRs showed a greater change in interferon (

The imprinted mouse gene Gnas produces the G protein ␣-subunit G S ␣ and several other gene products by using alternative promoters and first exons. G S ␣ is maternally expressed in some tissues and biallelically expressed in most other tissues, while the gene products NESP55 and XL␣s are maternally and paternally expressed, respectively. We investigated the mechanisms of Gnas imprinting. The G S ␣ promoter and first exon are not methylated on either allele. A further upstream region (approximately from positions ؊3400 to ؊939 relative to the G S ␣ translational start site) is methylated only on the maternal allele in all adult somatic tissues and in early postimplantation development. Within this region lies a fourth promoter and first exon (exon 1A) that generates paternal-specific mRNAs of unknown function. Exon 1A and G S ␣ mRNAs have similar expression patterns, making competition between their promoters unlikely. Differential methylation in this region is established during gametogenesis, being present in oocytes and absent in spermatozoa, and is maintained in preimplantation E3.5d blastocysts. Therefore, this region is a methylation imprint mark. In contrast, differential methylation of the NESP55 and XL␣s promoter regions (Nesp and Gnasxl) is not established during gametogenesis. The methylation imprint mark that we identified may be important for the tissue-specific imprinting of G S ␣.

The cleavage of sphingoid base phosphates by sphingosine-1-phosphate (S1P) lyase to produce phosphoethanolamine and a fatty aldehyde is the final degradative step in the sphingolipid metabolic pathway. We have studied mice with an inactive S1P lyase gene and have found that, in addition to the expected increase of sphingoid base phosphates, other sphingolipids (including sphingosine, ceramide, and sphingomyelin) were substantially elevated in the serum and/or liver of these mice. This latter increase is consistent with a reutilization of the sphingosine backbone for sphingolipid synthesis due to its inability to exit the sphingolipid metabolic pathway. Furthermore, the S1P lyase deficiency resulted in changes in the levels of serum and liver lipids not directly within the sphingolipid pathway, including phospholipids, triacyglycerol, diacylglycerol, and cholesterol. Even though lipids in serum and lipid storage were elevated in liver, adiposity was reduced in the S1P lyasedeficient mice. Microarray analysis of lipid metabolism genes in liver showed that the S1P lyase deficiency caused widespread changes in their expression pattern, with a significant increase in the expression of PPAR␥, a master transcriptional regulator of lipid metabolism. However, the mRNA expression of the genes encoding the sphingosine kinases and S1P phosphatases, which directly control the levels of S1P, were not significantly changed in liver of the S1P lyase-deficient mice. These results demonstrate that S1P lyase is a key regulator of the levels of multiple sphingolipid substrates and reveal functional links between the sphingolipid metabolic pathway and other lipid metabolic pathways that may be mediated by shared lipid substrates and changes in gene expression programs. The disturbance of lipid homeostasis by altered sphingolipid levels may be relevant to metabolic diseases.Sphingolipid metabolism generates diverse lipid molecules that are utilized by cells in multiple ways (Fig. 1A) (1, 2). Complex sphingolipids, such as sphingomyelin and glycosphingolipids, are structural components of cell membranes and drive the formation of plasma membrane lipid domains by virtue of their interactions with sterols. Metabolic intermediates, notably sphingosine, ceramide, and sphingosine-1-phosphate (S1P), 3 serve as bioactive molecules by regulating cellular signaling pathways. An additional function of sphingolipid metabolism is the synthesis of substrates that are utilized by other lipid metabolic hubs. However, the functional, regulatory, and physiological significance of the intersection of sphingolipid metabolism with other lipid pathways is not well understood.A decisive step in the sphingolipid metabolic pathway is carried out by S1P lyase, encoded by the Sgpl1 gene (3, 4). S1P lyase, which resides in the endoplasmic reticulum and is widely distributed in tissues, catalyzes the final degradative step in the sphingolipid metabolic pathway with the cleavage of phosphorylated sphingoid bases to generate phosphoethanolamine and a fatty aldehyd...