Diurnal Variations of Mouse Plasma and Hepatic Bile Acid Concentrations as well as Expression of Biosynthetic Enzymes and Transporters

Diurnal fluctuation of bile acid (BA) concentrations in the enterohepatic system of mammals has been known for a long time. Recently, BAs have been recognized as signaling molecules beyond their well-established roles in dietary lipid absorption and cholesterol homeostasis.The current study depicted diurnal variations of individual BAs detected by ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) in serum and livers collected from C57BL/6 mice fed a regular chow or a chow containing cholestyramine (resin). Circadian rhythms of mRNA of vital BA-related nuclear receptors, enzymes, and transporters in livers and ilea were determined in control- and resin-fed mice, as well as in farnesoid X receptor (FXR) null mice. The circadian profiles of BAs showed enhanced bacterial dehydroxylation during the fasting phase and efficient hepatic reconjugation of BAs in the fed phase. The resin removed more than 90% of BAs with β-hydroxy groups, such as muricholic acids and ursodeoxycholic acid, from serum and livers, but did not exert as significant influence on CA and CDCA in both compartments. Both resin-fed and FXR-null mouse models indicate that BAs regulate their own biosynthesis through the FXR-regulated ileal fibroblast growth factor 15. BA flux also influences the daily mRNA levels of multiple BA transporters.BA concentration and composition exhibit circadian variations in mouse liver and serum, which influences the circadian rhythms of BA metabolizing genes in liver and ileum. The diurnal variations of BAs appear to serve as a signal that coordinates daily nutrient metabolism in mammals

Hepatic alterations are accompanied by changes to bile acid transporter-expressing neurons in the hypothalamus after traumatic brain injury

Annually, there are over 2 million incidents of traumatic brain injury (TBI) and treatment options are non-existent. While many TBI studies have focused on the brain, peripheral contributions involving the digestive and immune systems are emerging as factors involved in the various symptomology associated with TBI. We hypothesized that TBI would alter hepatic function, including bile acid system machinery in the liver and brain. The results show activation of the hepatic acute phase response by 2 hours after TBI, hepatic inflammation by 6 hours after TBI and a decrease in hepatic transcription factors, Gli 1, Gli 2, Gli 3 at 2 and 24 hrs after TBI. Bile acid receptors and transporters were decreased as early as 2 hrs after TBI until at least 24 hrs after TBI. Quantification of bile acid transporter, ASBT-expressing neurons in the hypothalamus, revealed a significant decrease following TBI. These results are the first to show such changes following a TBI, and are compatible with previous studies of the bile acid system in stroke models. The data support the emerging idea of a systemic influence to neurological disorders and point to the need for future studies to better define specific mechanisms of action

Cardiac tissue engineering and regeneration using cell-based therapy

Mohammad T Alrefai,1–3 Divya Murali,4 Arghya Paul,4 Khalid M Ridwan,1,2 John M Connell,1,2 Dominique Shum-Tim1,2 1Division of Cardiac Surgery, 2Division of Surgical Research, McGill University Health Center, Montreal, QC, Canada; 3King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia; 4Department of Chemical and Petroleum Engineering, School of Engineering, University of Kansas, Lawrence, KS, USA Abstract: Stem cell therapy and tissue engineering represent a forefront of current research in the treatment of heart disease. With these technologies, advancements are being made into therapies for acute ischemic myocardial injury and chronic, otherwise nonreversible, myocardial failure. The current clinical management of cardiac ischemia deals with reestablishing perfusion to the heart but not dealing with the irreversible damage caused by the occlusion or stenosis of the supplying vessels. The applications of these new technologies are not yet fully established as part of the management of cardiac diseases but will become so in the near future. The discussion presented here reviews some of the pioneering works at this new frontier. Key results of allogeneic and autologous stem cell trials are presented, including the use of embryonic, bone marrow-derived, adipose-derived, and resident cardiac stem cells. Keywords: stem cells, cardiomyocytes, cardiac surgery, heart failure, myocardial ischemia, heart, scaffolds, organoids, cell sheet and tissue engineerin

SREBP2 mediates the modulation of intestinal NPC1L1 expression by curcumin

Curcumin, the major phenolic compound in the spice turmeric, exhibits numerous biological effects, including lowering plasma cholesterol and preventing diet-induced hypercholesterolemia. The mechanisms underlying the hypocholesterolemic effect of curcumin are not fully understood. In this regard, intestinal Niemann-Pick C1-like 1 (NPC1L1) cholesterol transporter, the molecular target of intestinal cholesterol absorption inhibitor ezetimibe, plays an essential role in the maintenance of cholesterol homeostasis. The current studies were designed to investigate the effect of curcumin on NPC1L1 function, expression, and promoter activity in intestinal Caco-2 monolayers. NPC1L1 function was evaluated by the measurement of ezetimibe-sensitive [3H]cholesterol esterification. Relative abundance of NPC1L1 mRNA and protein was evaluated by real-time PCR and Western blotting, respectively. Luciferase assays were used to measure NPC1L1 promoter activity. Our results showed that curcumin significantly inhibited ezetimibe-sensitive cholesterol esterification in a dose-dependent manner with a maximum decrease (by 52% compared with control) occurring at 50 μM concentration. Curcumin treatment of Caco-2 monolayers also significantly decreased NPC1L1 mRNA and protein expression. Similarly, the promoter activity of the NPC1L1 gene was inhibited significantly (55%) by 50 μM curcumin. The decrease in NPC1L1 promoter activity by curcumin was associated with a reduction in the expression and the DNA-binding activity of the sterol response element-binding protein 2 (SREBP2) transcription factor. Furthermore, the overexpression of active SREBP2 protected NPC1L1 from the inhibitory effect of curcumin. Our studies demonstrate that curcumin directly modulates intestinal NPC1L1 expression via transcriptional regulation and the involvement of SREBP2 transcription factor

13109 Phosphorylation state of Myristoylated Alanine-Rich C-Kinase Substrate Effector Domain mimetics determines its cytotoxicity in glioblastoma and macrophage model

ABSTRACT IMPACT: This study provides insight into how MED2 impacts the immune cells surrounding glioblastoma that help it to grow and spread; having a more complete understanding of how MED2 works will help us better develop therapies that may one day enter the clinic to improve patient outcomes in glioblastoma. OBJECTIVES/GOALS: The purpose of this study was to determine whether the phosphorylation state of the MED2 peptide impacts its biological activity in GBM and macrophages. MED2 variants include the phosphorylatable wild-type (MED2), pseudo-phosphorylated (MED2-PP), non-phosphorylatable (MED2-NP) and control length (CTL2) peptides. METHODS/STUDY POPULATION: MED2, MED2-NP, MED2-PP, and CTL2 were screened against a panel of molecularly characterized glioblastoma patient derived xenografts and IL4/13 stimulated M2-like THP-1 macrophages. The luminescent cell viability assay, CellTiter-Glo, was used to determine viability. RESULTS/ANTICIPATED RESULTS: The proneural lines XD456 and X1441 were highly sensitive to 5 µM MED2 and 5 µM MED2NP compared to 5 µM MED2PP (p&lt;0.001). There was no statistically significant difference between untreated, 5 µM CTL2, and 5 µM MED2PP groups or between the MED2NP and MED2 treated groups. M2-like THP-1 macrophages were highly sensitive to 10 µM MED2NP compared to 10 µM CTL2 (p&lt;0.01) and 10 µM MED2PP (p&lt;0.01) No statistically significant difference was observed between untreated, 10 µM MED2, 10 µM MED2PP, and 10 µM CTL2 groups. DISCUSSION/SIGNIFICANCE OF FINDINGS: The phosphorylation state of MED2 determines its toxicity. When MED2 is phosphorylated, it is nontoxic to GBM or M2-like macrophages. The non-phosphorylatable version is toxic to both GBM and M2-like macrophages. The wild-type peptide is toxic to GBM but not M2-like macrophages, suggesting that MED2 may be phosphorylated in M2-like macrophages.</jats:p