title: Effects of metformin on human monocytic THP-1 cells - Implications for type 2 diabetes mellitus

authors: Tsuei, An-Chi

subjects: Metformin

abstract: Metformin is an anti-hyperglycaemic agent widely prescribed for type 2 diabetes (T2D). Despite decades of clinical use, its exact pharmacological mechanism(s) is yet to be definitively determined. Accumulative data have shown its mild inhibitory effect on the complex 1 of the mitochondrial respiratory chain, which is thought to contribute to its anti-hyperglycaemic effect. Metformin is also thought to have a protective effect on cardiovascular disease (CVD), the most common complication in T2D. It is widely accepted that T2D is an inflammatory state thus it is not surprising that T2D patients have 2-4 times higher risk in developing CVD. Furthermore, the pathology of T2D has been proposed to involve dysfunctioning mitochondria, the organelle of energy sensing and production. The use of metformin, a mitochondria inhibitor, in cells under mitochondrial stress led us to speculate the physiological responses that ensue.
To understand metformin‟s mode of action and its involvement in inflammation processes the human monocytic leukemia THP-1 cells were used in this study. Since studies of metformin on this cell type is scarce if not non-existence the first task was to determine its cytoxicity in this cell line. Next the mRNA and protein expressions of heat shock protein 60 (Hsp60), a mitochondrial stress marker, was determined in metformin-treated THP-1 cells. Further, various cell types have shown surface expressed Hsp60 under stress conditions. Thus the study here attempted to optimise the detection of surface Hsp60 in THP-1 cells, as human Hsp60 has been shown to induce innate immune response. Localisation of Hsp60 on the cell surface in metformin-treated cells may exacerbate the already-inflammed state of T2D. Lastly, metformin‟s effect on PMA-stimulated monocyte differentiation was determined by the mRNA expression of CD14, a surface receptor on macrophages.
The results here agreed with published data that metformin at therapeutic concentrations are not cytotoxic and is a mild inhibitor of mitochondrial respiration. We also provide evidence that metformin up-regulated the mitochondria stress protein, Hsp60, in a time- and dose-dependent manner. In addition, live cell Hsp60 immunocytochemistry proved to be a promising method for surface Hsp60 detection in THP-1 cells. Finally, at the therapeutic concentration metformin caused a significant up-regulation in cd14 expression, which contradicts with much acclaimed protective effect of metformin in the literature.

text: Effects of metformin on human monocytic THP-1 cells - Implications for type 2 diabetes mellitus Metformin is an anti-hyperglycaemic agent widely prescribed for type 2 diabetes (T2D). Despite decades of clinical use, its exact pharmacological mechanism(s) is yet to be definitively determined. Accumulative data have shown its mild inhibitory effect on the complex 1 of the mitochondrial respiratory chain, which is thought to contribute to its anti-hyperglycaemic effect. Metformin is also thought to have a protective effect on cardiovascular disease (CVD), the most common complication in T2D. It is widely accepted that T2D is an inflammatory state thus it is not surprising that T2D patients have 2-4 times higher risk in developing CVD. Furthermore, the pathology of T2D has been proposed to involve dysfunctioning mitochondria, the organelle of energy sensing and production. The use of metformin, a mitochondria inhibitor, in cells under mitochondrial stress led us to speculate the physiological responses that ensue.
To understand metformin‟s mode of action and its involvement in inflammation processes the human monocytic leukemia THP-1 cells were used in this study. Since studies of metformin on this cell type is scarce if not non-existence the first task was to determine its cytoxicity in this cell line. Next the mRNA and protein expressions of heat shock protein 60 (Hsp60), a mitochondrial stress marker, was determined in metformin-treated THP-1 cells. Further, various cell types have shown surface expressed Hsp60 under stress conditions. Thus the study here attempted to optimise the detection of surface Hsp60 in THP-1 cells, as human Hsp60 has been shown to induce innate immune response. Localisation of Hsp60 on the cell surface in metformin-treated cells may exacerbate the already-inflammed state of T2D. Lastly, metformin‟s effect on PMA-stimulated monocyte differentiation was determined by the mRNA expression of CD14, a surface receptor on macrophages.
The results here agreed with published data that metformin at therapeutic concentrations are not cytotoxic and is a mild inhibitor of mitochondrial respiration. We also provide evidence that metformin up-regulated the mitochondria stress protein, Hsp60, in a time- and dose-dependent manner. In addition, live cell Hsp60 immunocytochemistry proved to be a promising method for surface Hsp60 detection in THP-1 cells. Finally, at the therapeutic concentration metformin caused a significant up-regulation in cd14 expression, which contradicts with much acclaimed protective effect of metformin in the literature.

year: 2010

title: Experiments in Predicting Biodegradability

authors: Blockeel, Hendrik

subjects: computer science

abstract: This paper is concerned with the use of AI techniques in ecology. More specifically, we present a novel application of inductive logic programming (ILP) in the area of quantitative structure-activity relationships (QSARs). The activity we want to predict is the biodegradability of chemical compounds in water. In particular, the target variable is the half-life for aerobic aqueous biodegradation. Structural descriptions of chemicals in terms of atoms and bonds are derived from the chemicals' SMILES encodings. The definition of substructures is used as background knowledge. Predicting biodegradability is essentially a regression problem, but we also consider a discretized version of the target variable. We thus employ a number of relational classification and regression methods on the relational representation and compare these to propositional methods applied to different propositionalizations of the problem. We also experiment with a prediction technique that consists of merging upper and lower bound predictions into one prediction. Some conclusions are drawn concerning the applicability of machine learning systems and the merging technique in this domain and the evaluation of hypotheses.

text: Experiments in Predicting Biodegradability This paper is concerned with the use of AI techniques in ecology. More specifically, we present a novel application of inductive logic programming (ILP) in the area of quantitative structure-activity relationships (QSARs). The activity we want to predict is the biodegradability of chemical compounds in water. In particular, the target variable is the half-life for aerobic aqueous biodegradation. Structural descriptions of chemicals in terms of atoms and bonds are derived from the chemicals' SMILES encodings. The definition of substructures is used as background knowledge. Predicting biodegradability is essentially a regression problem, but we also consider a discretized version of the target variable. We thus employ a number of relational classification and regression methods on the relational representation and compare these to propositional methods applied to different propositionalizations of the problem. We also experiment with a prediction technique that consists of merging upper and lower bound predictions into one prediction. Some conclusions are drawn concerning the applicability of machine learning systems and the merging technique in this domain and the evaluation of hypotheses.

year: 2004

title: Toitū Te Whānau, Toitū Te Iwi: A Community Approach to English Transition

authors: Berryman, Mere

subjects: Maori

abstract: The research project presented in this thesis documents and describes the outcomes of effective whānau (immediate and extended family), kura (school), student, and researcher collaboration. The researcher became part of a whānau-of-interest (Bishop, 1996b) in 1998 and 1999 when she was invited by this community to help develop a suitable programme to assist highly competent Māori immersion students in their transition to a bi-lingual secondary school (the only option available in their community). The whānau wanted students to begin their secondary schooling with an improved competence in reading and writing in English but without compromising their competency in Maori language. Prior to this programme few of the students had received any formal instruction in the English language.
After a ten-week intervention implemented mainly outside the classroom, the researcher found that whānau tutors had effectively implemented the programmes and that all Year 8 students were able to read stories (in English) and talk about them (in English) at age appropriate reading levels. They also displayed improved rates of writing in English while maintaining their high fluency in reading and writing in Māori. The 10-week programme and results were replicated over a further three terms with the Year 7 and again with the Year 6 students. The study employed a multiple baseline across groups, design. A collaborative story gathered from participants at the end of the programme, together with these process and outcome data, strongly support the successful outcomes of this "participant driven" (Bishop, 1996b) programme.

text: Toitū Te Whānau, Toitū Te Iwi: A Community Approach to English Transition The research project presented in this thesis documents and describes the outcomes of effective whānau (immediate and extended family), kura (school), student, and researcher collaboration. The researcher became part of a whānau-of-interest (Bishop, 1996b) in 1998 and 1999 when she was invited by this community to help develop a suitable programme to assist highly competent Māori immersion students in their transition to a bi-lingual secondary school (the only option available in their community). The whānau wanted students to begin their secondary schooling with an improved competence in reading and writing in English but without compromising their competency in Maori language. Prior to this programme few of the students had received any formal instruction in the English language.
After a ten-week intervention implemented mainly outside the classroom, the researcher found that whānau tutors had effectively implemented the programmes and that all Year 8 students were able to read stories (in English) and talk about them (in English) at age appropriate reading levels. They also displayed improved rates of writing in English while maintaining their high fluency in reading and writing in Māori. The 10-week programme and results were replicated over a further three terms with the Year 7 and again with the Year 6 students. The study employed a multiple baseline across groups, design. A collaborative story gathered from participants at the end of the programme, together with these process and outcome data, strongly support the successful outcomes of this "participant driven" (Bishop, 1996b) programme.

year: 2001