A regulatory module embedded in the coding region of Hoxa2 controls expression in rhombomere 2

Here, we define a gene regulatory network for Hoxa2, responsible for temporal and spatial expression in hindbrain development. Hoxa2 plays an important role in regulating the regional identity of rhombomere 2 (r2) and is the only Hox gene expressed in this segment. In this study, we found that a Hoxa2 cis-regulatory module consists of five elements that direct expression in r2 of the developing hindbrain. Surprisingly, the module is imbedded in the second coding exon of Hoxa2 and therefore may be constrained by both protein coding and gene regulatory requirements. This highly conserved enhancer consists of two consensus Sox binding sites and several additional elements that act in concert to direct strong r2 specific expression. Our findings provide important insight into the regulation of segmental identity in the anterior hindbrain. Furthermore, they have broader implications in designing arrays and interpreting data from global analyses of gene regulation because regulatory input from coding regions needs to be considered.     

Efficacy,safety, and tolerability of once-daily niacin for the treatment of dyslipidemia associated with type 2 diabetes: results of the assessment of diabetes control and evaluation of the efficacy of niaspan trial

BACKGROUND: Diabetic dyslipidemia is characterized by high triglyceride levels; low high-density lipoprotein cholesterol levels; small, dense low-density lipoprotein particles; and high free fatty acid levels. Niacin reduces concentrations of triglyceride-rich and small low-density lipoprotein particles while increasing high-density lipoprotein cholesterol levels. It also lowers levels of free fatty acids and lipoprotein(a). However, the use of niacin in patients with diabetes has been discouraged because high doses can worsen glycemic control. We evaluated the efficacy and safety of once-daily extended-release (ER) niacin in patients with diabetic dyslipidemia. METHODS: During a 16-week, double-blind, placebo-controlled trial, 148 patients were randomized to placebo (n = 49) or 1000 (n = 45) or 1500 mg/d (n = 52) of ER niacin. Sixty-nine patients (47%) were also receiving concomitant therapy with statins. RESULTS: Dose-dependent increases in high-density lipoprotein cholesterol levels (+19% to +24% [P<.05] vs placebo for both niacin dosages) and reductions in triglyceride levels (-13% to -28% [P<.05] vs placebo for the 1500-mg ER niacin) were observed. Baseline and week 16 values for glycosylated hemoglobin levels were 7.13% and 7.11%, respectively, in the placebo group; 7.28% and 7.35%, respectively, in the 1000-mg ER niacin group (P=.16 vs placebo); and 7.2% and 7.5%, respectively, in the 1500-mg ER niacin group (P=.048 vs placebo). Four patients discontinued participation because of inadequate glucose control. Rates of adverse event rates other than flushing were similar for the niacin and placebo groups. Four patients discontinued participation owing to flushing (including 1 receiving placebo). No hepatotoxic effects or myopathy were observed. CONCLUSION: Low doses of ER niacin (1000 or 1500 mg/d) are a treatment option for dyslipidemia in patients with type 2 diabetes.     

MHC class II-expressing hepatocytes function as antigen-presenting cells and activate specific CD4 T lymphocyutes

The ability to activate CD4 T cells is restricted to antigen-presenting cells that express major histocompatibility complex (MHC) class II molecules. Parenchymal cells normally do not express MHC class II molecules; however, in clinical hepatitis, viral or autoimmune, hepatocytes often exhibit aberrant MHC class II expression. It is not known whether MHC class II-expressing hepatocytes can function as antigen-presenting cells, but it has been suggested that aberrant MHC class II expression by parenchymal cells may cause autoimmune disease. Therefore, we generated transgenic mice that specifically overexpress class II transactivator molecules in hepatocytes. Hepatocytes from these mice exhibited stable MHC class II expression and were used to stimulate CD4 T cells from T-cell receptor transgenic mice and CD4 T-cell lines. MHC II-expressing hepatocytes featured costimulatory CD80 molecules and could serve as antigen-presenting cells that were able to process protein antigen and to activate specific CD4 T cells. Nevertheless, the transgenic mice with aberrant hepatocellular MHC class II expression did not exhibit any symptoms of autoimmune disease. In conclusion, MHC II-expressing hepatocytes, as found in clinical hepatitis, can present antigen and activate CD4 T cells. The ability of hepatocytes to present antigen on MHC II molecules does not seem to be a sufficient cause for inflammatory autoimmunity and hepatitis. However, we still need to explore whether such antigen presentation is occurring in vivo. The transgenic mice described in this study may serve as a model to study the immune interaction of hepatocytes and CD4 T cells in both in vitro and in vivo.     

Alcohol Abuse or Dependence Among Mexican American Women Who Report Violence

BACKGROUND: Violence against women has been linked to alcohol disorders in various populations. Few studies have assessed alcohol disorders among assaulted women in a general population of Mexican Americans. This study examined alcohol disorders among Mexican American women who reported physical or sexual assault. METHODS: Participants were women (n = 1516, ages 18-59) living in Fresno County, California, who were enrolled in a population-based, randomized household survey of Mexican-origin men and women. Crude and adjusted odds ratios (ORs) were calculated for alcohol dependence/abuse (ADA) and physical or sexual assault by a current partner or someone other than a current partner. RESULTS: Women who reported lifetime physical or sexual assault were significantly more likely to meet criteria for ADA (OR = 8.2; 95% confidence interval [CI], 4.4-15.4). After we adjusted for birthplace, age, income, and parental problem drinking, assaulted women were still 4.7 times more likely to meet criteria for ADA (CI, 2.1-10.4). Physical or sexual assault by someone other than a partner was more strongly associated with ADA (OR = 8.7; CI, 4.5-16.9) than assault by a current partner (OR = 3.2; CI, 1.3-7.6). Both physical (OR = 9.0; CI, 4.7-17.0) and sexual assault (OR = 4.7; CI, 2.2-10.0) by either type of perpetrator were associated with ADA. CONCLUSION: There is a strong association between reporting violence and having a lifetime history of ADA. Although temporal order could not be established, these findings highlight the importance of screening for physical and sexual assault in settings that treat alcohol disorders as well as screening for alcohol disorders among women who seek services related to previous or current violence.     

Phase-II metabolism limits the antiproliferative activity of urolithins in human colon cancer cells

Purpose

Urolithins, gut microbiota metabolites derived from ellagic acid and ellagitannins, reach micromolar concentrations in the colon lumen where can have anti-inflammatory and anticancer effects. The antiproliferative activity of urolithins (Uro-A, Uro-B, Uro-C and Uro-D) and their most relevant in vivo glucuronides were evaluated in three human colon cancer cell lines (Caco-2, SW480 and HT-29).

Methods

Cell proliferation was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide and Trypan blue exclusion assays. Cell cycle was evaluated by flow cytometry and urolithins metabolism by HPLC–MS/MS.

Results

Urolithins inhibited cell proliferation and cell cycle progression in a time- and dose-dependent manner and arrested the cells at S and G2/M phases, depending on the urolithin. Uro-A exerted the highest antiproliferative activity, followed by Uro-C, Uro-D and Uro-B. Unlike Caco-2 and SW480 cells, HT-29 cells partially overcame the effects after 48 h, which was related to the complete glucuronidation of urolithins. Uro-A or Uro-B glucuronides did not affect cell cycle and showed lower antiproliferative activity than their aglycone counterparts. Uro-A or Uro-B plus inhibitors of drug efflux ABC transporters partially prevented the glucuronidation of urolithins in HT-29 cells which became more sensitive.

Conclusions

Uro-A, Uro-B, Uro-C and Uro-D exerted different antiproliferative effects depending on the colon cancer cell line. We also report here, for the first time, the role of ABC transporters and Phase-II metabolism in HT-29 cells as a mechanism of cancer resistance against urolithins due to their conversion to glucuronide conjugates that exerted lower antiproliferative activity.