Formative assessment of Bachelor and Master student’s supervision

One of the most challenging parts of student’s supervision is to have theability to formulate a good assessment. This one should help students torealize how much they have learned and, consequently, to the supervisorsto improve their teaching skills (1, 2, 3). In my research field, we interview students before we accept them in the laboratory under our supervision. During the interview we have the opportunity to know about students’ background, expectations and social environment. Based on this information, the supervisor can adapt the contract and intended learning outcomes (ILOs) in order to get the best alignment.The challenge pops up in the assessment of students. They are formallyassessed on a report and a defense of their thesis, but generally they missa formative evaluation while they are in the laboratory performing experiments. Consequently, I have found really interesting for my final project of the Universitetspedægogikum course to focus on activities that can improve this part of the supervision in a research group

Regulation of N-Myc downstream regulated gene 2 by bile acids

Here we report that bile acid chenodeoxycholic acid (CDCA) and synthetic farnesoid X receptor (FXR) agonist GW4064 robustly induced tumor suppressor N-Myc downstream regulated gene 2 (NDRG2) expression in human hepatoma cells and primary hepatocytes. Knockdown of FXR abolished the induction by CDCA, whereas overexpre ssion of a constitutively active form of FXR increased NDRG2 expression. A FXR-response element was identified within intronic regions of human and murine genes. Moreover, mice given GW4064 exhib it an increase of Ndrg2 expression in liver and kidney, where both NDRG2 and FXR are enriched. The identification of NDRG2 as a bile acid regulated gene may provide novel knowledge toward the understanding of NDRG2 physiological function and the link between metabolism and cancer

The human Na⁺/H⁺ exchanger 1 is a membrane scaffold protein for extracellular signal-regulated kinase 2

Background Extracellular signal-regulated kinase 2 (ERK2) is an S/T kinase with more than 200 known substrates, and with critical roles in regulation of cell growth and differentiation and currently no membrane proteins have been linked to ERK2 scaffolding. Methods and results Here, we identify the human Na+/H+ exchanger 1 (hNHE1) as a membrane scaffold protein for ERK2 and show direct hNHE1-ERK1/2 interaction in cellular contexts. Using nuclear magnetic resonance (NMR) spectroscopy and immunofluorescence analysis we demonstrate that ERK2 scaffolding by hNHE1 occurs by one of three D-domains and by two non-canonical F-sites located in the disordered intracellular tail of hNHE1, mutation of which reduced cellular hNHE1-ERK1/2 co-localization, as well as reduced cellular ERK1/2 activation. Time-resolved NMR spectroscopy revealed that ERK2 phosphorylated the disordered tail of hNHE1 at six sites in vitro, in a distinct temporal order, with the phosphorylation rates at the individual sites being modulated by the docking sites in a distant dependent manner. Conclusions This work characterizes a new type of scaffolding complex, which we term a “shuffle complex”, between the disordered hNHE1-tail and ERK2, and provides a molecular mechanism for the important ERK2 scaffolding function of the membrane protein hNHE1, which regulates the phosphorylation of both hNHE1 and ERK2

The glutamate transport inhibitor DL-Threo-β-Benzyloxyaspartic acid (DL-TBOA) differentially affects SN38- and oxaliplatin-induced death of drug-resistant colorectal cancer cells

BACKGROUND: Colorectal cancer (CRC) is a leading cause of cancer death globally and new biomarkers and treatments are severely needed. METHODS: Here, we employed HCT116 and LoVo human CRC cells made resistant to either SN38 or oxaliplatin, to investigate whether altered expression of the high affinity glutamate transporters Solute Carrier (SLC)-1A1 and -1A3 (EAAT3, EAAT1) is associated with the resistant phenotypes. Analyses included real-time quantitative PCR, immunoblotting and immunofluorescence analyses, radioactive tracer flux measurements, and biochemical analyses of cell viability and glutathione content. Results were evaluated using one- and two-way ANOVA and Students two-tailed t-test, as relevant. RESULTS: In SN38-resistant HCT116 and LoVo cells, SLC1A1 expression was down-regulated ~60 % and up-regulated ~4-fold, respectively, at both mRNA and protein level, whereas SLC1A3 protein was undetectable. The changes in SLC1A1 expression were accompanied by parallel changes in DL-Threo-β-Benzyloxyaspartic acid (TBOA)-sensitive, UCPH101-insensitive [(3)H]-D-Aspartate uptake, consistent with increased activity of SLC1A1 (or other family members), yet not of SLC1A3. DL-TBOA co-treatment concentration-dependently augmented loss of cell viability induced by SN38, while strongly counteracting that induced by oxaliplatin, in both HCT116 and LoVo cells. This reflected neither altered expression of the oxaliplatin transporter Cu(2+)-transporter-1 (CTR1), nor changes in cellular reduced glutathione (GSH), although HCT116 cell resistance per se correlated with increased cellular GSH. DL-TBOA did not significantly alter cellular levels of p21, cleaved PARP-1, or phospho-Retinoblastoma protein, yet altered SLC1A1 subcellular localization, and reduced chemotherapy-induced p53 induction. CONCLUSIONS: SLC1A1 expression and glutamate transporter activity are altered in SN38-resistant CRC cells. Importantly, the non-selective glutamate transporter inhibitor DL-TBOA reduces chemotherapy-induced p53 induction and augments CRC cell death induced by SN38, while attenuating that induced by oxaliplatin. These findings may point to novel treatment options in treatment-resistant CRC. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12885-015-1405-8) contains supplementary material, which is available to authorized users

Identificación de nuevos genes diana del receptor nuclear FXR

[spa] Las sales biliares son cruciales para la solubilización y absorción en el intestino de las grasas y las vitaminas liposolubles procedentes de la dieta. Estas sales biliares son sintetizadas a partir de colesterol en los hepatocitos, lo que representa la mayor vía de eliminación de colesterol del cuerpo. Además de este importante papel fisiológico, las sales biliares también actúan como moléculas de señalización endocrina que afectan a múltiples órganos. Para ejercer estos efectos, los ácidos biliares se unen al receptor de membrana TGR5 (G protein-coupled bile acid receptor 1) y al receptor nuclear FXR (Farnesoid X receptor). Este receptor nuclear es capaz de regular la síntesis de ácidos biliares, inhibiendo la expresión de una enzima clave para su síntesis. FXR también regula genes implicados en el transporte de estos ácidos biliares hacia el exterior de la célula, no solo a nivel hepático sino también intestinal. Por todo esto se considera que FXR es un sensor de los ácidos biliares en el contexto enterohepático. Además del papel crucial que desarrolla FXR en la homeostasis de los ácidos biliares, también está involucrado en la regulación del colesterol y en el metabolismo de lípidos y glucosa. Estudios recientes han demostrado la participación de FXR en nuevas funciones relacionadas con procesos biológicos como la regeneración hepática (Huang W et al, 2006) y la inhibición de la progresión tumoral (Yang F et al, 2007; Modica S et al, 2008). La identificación de la expresión de este receptor nuclear en tejidos vasculares ha relacionado a FXR con enfermedades tan extendidas como la aterosclerosis (Bishop-Bailey, 2004). Por todo esto, FXR se ha convertido en una esperanza terapéutica en la lucha contra múltiples enfermedades. Se han empleado aproximaciones genómicas y farmacológicas con el objetivo de identificar nuevos genes diana humanos del receptor nuclear FXR. Los experimentos realizados con micromatrices en diferentes tejidos, donde la expresión de FXR está reportada, han permitido cumplir dicho objetivo. Por otro lado, los numerosos experimentos de biología molecular llevados a cabo han confirmado los resultados obtenidos y han permitido caracterizar los mecanismos de regulación que ejerce FXR sobre los nuevos genes humanos identificados. La investigación realizada ha evidenciado que FXR regula genes involucrados en el transporte de ácidos grasos y retinol, así como en la ubiquitinación, el transporte vesicular o la supervivencia celular. De la misma manera, se ha descubierto la regulación por FXR de genes asociados a enfermedades como la inflamación, el alcoholismo, la litiasis o el cáncer.[eng] Bile salts are crucial for the solubilization and absorption in the intestine of fats and vitamins from the diet. These bile salts are synthesized from cholesterol in hepatocytes, which represents the major route of elimination of cholesterol from the body. Besides this important physiological role, bile salts also act as signaling molecules that affect multiple endocrine organs. To exert these effects, bile acids bind to the membrane receptor TGR5 (G protein-coupled bile acid receptor 1) and the nuclear receptor FXR (Farnesoid X receptor). This nuclear receptor is able to regulate the bile acid synthesis by inhibition of a key enzyme for its synthesis and regulation of genes involved in the transport of bile acids to the outside of the cell, in the liver and intestine. By all this FXR is considered a bile acid sensor in the enterohepatic context. On the other hand, recent studies have shown the involvement of FXR in new functions related to biological processes such as liver regeneration (Huang W et al, 2006) and inhibition of tumor progression (Yang F et al, 2007; Modica S et al, 2008). The identification of the expression of FXR in vascular tissues it has been associated with diseases such as atherosclerosis (Bishop-Bailey, 2004). For all this, FXR has become a therapeutic hope in the fight against multiple diseases. Genomic approaches have been employed with the pharmacological target and identify novel human target genes of FXR. The microarrays in different tissues, where expression of FXR is reported, have allowed us to get this objective. Furthermore, molecular biology experiments carried out have confirmed the results obtained and allowed characterize the mechanisms of regulation exerted on new human target genes. Research has shown that FXR regulates genes involved in the transport of fatty acids and retinol, ubiquitination, vesicular transport or cell survival. Similarly, it has been discovered regulation by FXR of genes associated with diseases such as inflammation, alcoholism, lithiasis or cancer

Regulation of human class I alcohol dehydrogenases by bile acids

Class I alcohol dehydrogenases (ADH1s) are the rate-limiting enzymes for ethanol and vitamin A (retinol) metabolism in the liver . Because previous studies have shown that human ADH1 enzymes may participate in bile acid metabolism, we investigated whether the bile acid-activated nuclear receptor farnesoid X receptor (FXR) regulates ADH1 genes. In human hepatocytes, both the endogenous FXR ligand chenodeoxycholic acid and synthetic FXR-specific agonist GW4064 increased ADH1 mRNA, protein, and activity. Moreover, overexpression of a constitutively active form of FXR induced ADH1A and ADH1B expression, whereas silencing of FXR abolished the effects of FXR agonists on ADH1 expression and activity. Transient transfection studies and electrophoretic mobility shift assays revealed functional FXR response elements in the ADH1A and ADH1B proximal promoters, thus indicating that both genes are direct targets of FXR. These findings provide the first evidence for direct connection of bile acid signaling and alcohol metabolism

Regulation of N-Myc downstream regulated gene 2 by bile acids

Here we report that bile acid chenodeoxycholic acid (CDCA) and synthetic farnesoid X receptor (FXR) agonist GW4064 robustly induced tumor suppressor N-Myc downstream regulated gene 2 (NDRG2) expression in human hepatoma cells and primary hepatocytes. Knockdown of FXR abolished the induction by CDCA, whereas overexpre ssion of a constitutively active form of FXR increased NDRG2 expression. A FXR-response element was identified within intronic regions of human and murine genes. Moreover, mice given GW4064 exhib it an increase of Ndrg2 expression in liver and kidney, where both NDRG2 and FXR are enriched. The identification of NDRG2 as a bile acid regulated gene may provide novel knowledge toward the understanding of NDRG2 physiological function and the link between metabolism and cancer