The present study cloned successfully two lipid-metabolism genes, lipoprotein lipase (LPL) and fatty acid binding protein (FABPs) from cobia and studied the mRNA expressions of the two genes and their upstream gene PPARs when the cobia were fed diets containing 15% lipid. Among the lipids, 6% was fish oil and the remaining 9% were supplemented by fish oil (FO, rich in n-3 HUFA), perilla oil (PE, rich in 18:2 n-6), safflower oil (SA, rich in 18:2 n-6), olive oil (OL, rich in 18:1 n-9) or palm oil (PA, rich in 16:0). The whole sequences of LPL, liver-FABP (L-FABP) and muscle-FABP (M-FABP) encode 520, 126 and 133 amino acids, respectively. RT-PCR and real time PCR analyses based on these gene sequences show that the mRNA expressions of L-FABP and M-FABP in the tissue of the cobia were diet-specific. The mRNA expression of LPL, on the other hand, did not respond to the treatments, except in visceral fat depot. Linear regression analysis shows that the mRNA expression of LPL in the liver and muscle was positively (P<0.05) related to dietary fatty acids and ther concentration, but that in the visceral fat depot was negatively related. The mRNA expression of FABPs was also positively correlated with dietary fatty acid levels. Among all fatty acids, the levels of C14:0, C20:1 n-9, EPA and DHA were positively correlated with the mRNA expression of PPAR£^and also with FABPs mRNA expression in the visceral fat depot and LPL mRNA expression in the muscle. Thus, LPL, L-FABP and M-FABP mRNA expression of the cobia were highly influenced by the kind and amount of dietary fatty acids. The role of PPARs was not clearly demonstrated.

Liver fatty acid binding protein (L-FABP) binds and translocates many lipophilic substrates within the cytoplasm including long chain fatty acids. Moreover it was reported that L-FABP possesses antioxidative properties within hepatocytes. However, the mechanism of L-FABP’s antioxidative activity remains to be determined. Peroxisome proliferator activated receptor (PPAR) agonists and antagonists can regulate L-FABP levels. However, it needs to be investigated how PPAR agonists and antagonists regulate L-FABP expression. And whether the altered expression of L-FABP by these agents will affect its antioxidative properties within hepatocytes remains unclear. In this thesis we employed clofibrate (PPARα agonist), MK886 (PPARα antagonist), and GW9662 (PPARγ antagonist) to elucidate the mechanism whereby PPAR regulate L-FABP expression and what effect such expression has on the antioxidant activity of L-FABP in CRL-1548 hepatoma cells. Clofibrate served to upregulate L-FABP expression while MK886 and GW9662 were employed to inhibit L-FABP expression. The principal findings revealed that clofibrate treatment enhanced L-FABP mRNA stability and transcription, which resulted in increased L-FABP levels, while MK866 and GW9662 reduced these levels. We also demonstrated that increases in L-FABP levels were associated with reduced cytosolic reactive oxygen species (ROS), while L-FABP siRNA knockdown resulted in a decrease in L-FABP expression and an associated increase in ROS levels. The antioxidant mechanism of recombinant rat L-FABP in the presence of a hydrophilic (AAPH) and lipophilic (AMVN) free radical generators was also evaluated. Recombinant rat L-FABP was produced in E. coli and its amino acid sequence was confirmed by MALDI QqTOF MS. Antioxidant activity was assayed using the thiobarbituric acid method. Ascorbic acid served as a positive control for the AAPH reaction while α-tocopherol was used as a positive control for the AMVN reaction. The antioxidant activity of recombinant L-FABP was greater when free radicals were generated with AAPH than AMVN. Oxidative modification of L-FABP included up to five methionine oxidative peptides with a total of 80 Da mass shift compared to native L-FABP. These findings suggest that the mechanism of L-FABP’s antioxidant activity involved the reaction of methionine with free radicals. In conclusion, L-FABP expression is regulated by PPAR agonists and antagonists through transcription and mRNA stability. Moreover, methionine residues appear to play an important role in the antioxidative activity of L-FABP.

Liver fatty acid binding protein (L-FABP) binds and translocates many lipophilic substrates within the cytoplasm including long chain fatty acids. Moreover it was reported that L-FABP possesses antioxidative properties within hepatocytes. However, the mechanism of L-FABP’s antioxidative activity remains to be determined. Peroxisome proliferator activated receptor (PPAR) agonists and antagonists can regulate L-FABP levels. However, it needs to be investigated how PPAR agonists and antagonists regulate L-FABP expression. And whether the altered expression of L-FABP by these agents will affect its antioxidative properties within hepatocytes remains unclear. In this thesis we employed clofibrate (PPARα agonist), MK886 (PPARα antagonist), and GW9662 (PPARγ antagonist) to elucidate the mechanism whereby PPAR regulate L-FABP expression and what effect such expression has on the antioxidant activity of L-FABP in CRL-1548 hepatoma cells. Clofibrate served to upregulate L-FABP expression while MK886 and GW9662 were employed to inhibit L-FABP expression. The principal findings revealed that clofibrate treatment enhanced L-FABP mRNA stability and transcription, which resulted in increased L-FABP levels, while MK866 and GW9662 reduced these levels. We also demonstrated that increases in L-FABP levels were associated with reduced cytosolic reactive oxygen species (ROS), while L-FABP siRNA knockdown resulted in a decrease in L-FABP expression and an associated increase in ROS levels. The antioxidant mechanism of recombinant rat L-FABP in the presence of a hydrophilic (AAPH) and lipophilic (AMVN) free radical generators was also evaluated. Recombinant rat L-FABP was produced in E. coli and its amino acid sequence was confirmed by MALDI QqTOF MS. Antioxidant activity was assayed using the thiobarbituric acid method. Ascorbic acid served as a positive control for the AAPH reaction while α-tocopherol was used as a positive control for the AMVN reaction. The antioxidant activity of recombinant L-FABP was greater when free radicals were generated with AAPH than AMVN. Oxidative modification of L-FABP included up to five methionine oxidative peptides with a total of 80 Da mass shift compared to native L-FABP. These findings suggest that the mechanism of L-FABP’s antioxidant activity involved the reaction of methionine with free radicals. In conclusion, L-FABP expression is regulated by PPAR agonists and antagonists through transcription and mRNA stability. Moreover, methionine residues appear to play an important role in the antioxidative activity of L-FABP.

Adipositas und die damit verbundenen Folgeerkrankungen sind eine der zentralen Gesund-heitsherausforderungen unserer Zeit. Dauerhafte Adipositas führt zu einer Dysregulation fettgewebseigener Peptidhormone. Diese sogenannten Adipokine stellen ein Verbindungsglied zwischen Fettgewebsakkumulation und den vielfältigen Adipositaskomplikationen des gesamten Organismus dar. Adipocyte fatty acid binding protein (AFABP) wurde in den letzten Jahren als zirkulierendes Adipokin mit diabetogenen, proinflammatorischen und proateriosklerotischen Effekten etabliert. Zu Beginn der Dissertation lagen unzureichende Erkenntnisse über die Elimination von AFABP sowie die Regulation des Adipokins bei eingeschränkter Nierenfunktion vor. Aus diesem Grund untersucht die vorliegende Arbeit die AFABP-Regulation in Abhängigkeit von der Nierenfunktion in 532 Patienten mit chronischer Niereninsuffizienz (Studienpopulation 1) und 32 Patienten mit akuter Nierenfunktionsverminderung nach Nephrektomie (Studienpopulation 2). In beiden Kohorten stiegen die medianen AFABP-Serumkonzentrationen mit abfallender Nierenfunktion an. Zudem waren Marker der Nierenfunktion in beiden Studienpopulationen die stärksten unabhängigen Prädiktoren für zirkulierendes AFABP. Untersuchungen aus der Arbeitsgruppe zur AFABP-Regulation in einem Rattenmodell der akuten Niereninsuffizienz unterstützen die klinischen Studienergebnisse. Zusammenfassend zeigen diese Ergebnisse zum ersten Mal signifikant steigende AFABP-Serumspiegel bei chronischer und akuter Nierenfunktionsstörung, sowie bei akutem Abfall der Nierenfunktion. Diese Befunde stützen die Hypothese, dass AFABP renal eliminiert wird. Inwiefern AFABP darüber hinaus in die Pathogenese der chronischen Niereninsuffizienz eingreift, muss in weiterführenden Studien beleuchtet werden.

The desert ant Cataglyphis fortis is one of the hyperthermophilic species of Cataglyphis. It lives in the Sahara desert and forages during the hottest hours of the day when it can get up to 70˚C in the sand. The body temperature of the ant during the foraging runs can reach a maximum of 55˚C. Since C.fortis is one of few eukaryotic hyperthermophilic species, its proteins probably have a high thermostability. Investigating the thermostability can give valuable information about the principles of protein folding and stability in hyperthermophiles.Fatty acid binding proteins (FABPs) have an important role in the cell taking up and transporting fatty acids and regulating metabolic and inflammatory pathways. FABPs have been extensively studied and structures from several species have been determined. The determined structures of all FABPs are very similar why thermostability studies of FABP from C.fortis are highly relevant.Fluorescence spectroscopy is an easy and fast method to measure intrinsic protein fluorescence. Tryptophans were genetically introduced into three different positions in FABP to be used as environmental sensitive probes. Complementing the measurement results with a model of the 3D structure of FABP from C.fortis gave additional information about the ligand binding.The (local) thermostability of the mutants can be detected by shift in wavelength maximum during temperature ramping experiments. All mutants are stabilised in the presence of fatty acids. The mutant with tryptophan positioned closest to the supposed ligand binding residues (Y11W) is most affected. The mutant with tryptophan situated farthest from the supposed binding residues (Y52W) shows a stabilisation of Tm less evident than for Y11W. Thus, the structural changes following fatty acid binding are more obvious in the environment close to the binding site.However, the third mutant C87W shows no significant stabilisation although positioned closer to the fatty acid binding site than Y52. This is probably due to the size difference between the original and introduced amino acid in the mutation. Since the high value of the starting λmax for C87W implies that C87W is quite exposed to the aqueous solvent, the residue is likely to not have subsumed in the protein tertiary structure.Further, the myristic acid stabilise the melting temperature of all the mutants while octanoic acid only has a local effect of Y11W increasing the cooperativity. This implies different binding properties and that myristic acid stabilise the entire protein while octanoic acid only has a local stabilisation effect around the ligand binding site.

Adipositas und die damit verbundenen Folgeerkrankungen sind eine der zentralen Gesund-heitsherausforderungen unserer Zeit. Dauerhafte Adipositas führt zu einer Dysregulation fettgewebseigener Peptidhormone. Diese sogenannten Adipokine stellen ein Verbindungsglied zwischen Fettgewebsakkumulation und den vielfältigen Adipositaskomplikationen des gesamten Organismus dar. Adipocyte fatty acid binding protein (AFABP) wurde in den letzten Jahren als zirkulierendes Adipokin mit diabetogenen, proinflammatorischen und proateriosklerotischen Effekten etabliert. Zu Beginn der Dissertation lagen unzureichende Erkenntnisse über die Elimination von AFABP sowie die Regulation des Adipokins bei eingeschränkter Nierenfunktion vor. Aus diesem Grund untersucht die vorliegende Arbeit die AFABP-Regulation in Abhängigkeit von der Nierenfunktion in 532 Patienten mit chronischer Niereninsuffizienz (Studienpopulation 1) und 32 Patienten mit akuter Nierenfunktionsverminderung nach Nephrektomie (Studienpopulation 2). In beiden Kohorten stiegen die medianen AFABP-Serumkonzentrationen mit abfallender Nierenfunktion an. Zudem waren Marker der Nierenfunktion in beiden Studienpopulationen die stärksten unabhängigen Prädiktoren für zirkulierendes AFABP. Untersuchungen aus der Arbeitsgruppe zur AFABP-Regulation in einem Rattenmodell der akuten Niereninsuffizienz unterstützen die klinischen Studienergebnisse. Zusammenfassend zeigen diese Ergebnisse zum ersten Mal signifikant steigende AFABP-Serumspiegel bei chronischer und akuter Nierenfunktionsstörung, sowie bei akutem Abfall der Nierenfunktion. Diese Befunde stützen die Hypothese, dass AFABP renal eliminiert wird. Inwiefern AFABP darüber hinaus in die Pathogenese der chronischen Niereninsuffizienz eingreift, muss in weiterführenden Studien beleuchtet werden.

Due to its significance in many cellular functions, fatty acid binding protein 7 (FABP7) has become a rising topic of interest for many scientists. Immunocytochemistry was used to map the distribution of FABP7 and test whether the amount of FABP7 immunoreactivity (FABP7-IR) differed in animals that were defeated in a fight, as compared to control animals that did not engage in any social interaction. The male green anole was used as the subject because its natural tendency to establish social classes within its species provides an ideal model to observe for variation in FABP7-IR. The results showed FABP7-IR in cells and fibers of the cortex, hypothalamus, thalamus, medial preoptic area, dorsoventricular ridge, amygdala, suprachiasmatic nucleus, nucleus accumbens, nucleus rotundus, habenular area, tectum, dorsal noradrenergic and lateral forebrain bundles, and lining the third and lateral ventricles. Qualitative observation suggested higher FABP7 levels in socially defeated males than controls in all areas.

Duplicated genes are present in the teleost fish lineage owing to a whole-genome duplication (WGD) event that occured ~ 230-400 million years ago. In the duplication-degeneration-complementation (DDC) model, partitioning of ancestral functions (subfunctionalization) and acquisition of novel functions (neofunctionalization) have been proposed as principal processes for the retention of duplicated genes in the genome. The DDC model was tested by analyzing the differential tissue-specific distribution of transcripts for the duplicated fatty acid-binding protein 10 (fabp10) genes in embryos, larvae and adult zebrafish (Danio rerio). The distribution of zebrafish fabp10a and fabp10b transcripts show a strikingly different tissue-specific pattern leading us to suggest that the zebrafish fabp10 duplicates had been retained in the genome owing to neofunctionalization. In another experiment to test the DDC model, transcriptional regulation of duplicated fabp genes was analyzed in zebrafish fed clofibrate, a peroxisome proliferator-activated receptor (PPAR) agonist. Clofibrate increased the steady-state level of both the duplicated copies of fabp1a/fabp1b.1, and fabp7a/fabp7b mRNA and heteronuclear RNA (hnRNA), but in different tissues of zebrafish. The steady-state level of fabp10a and fabp11a mRNA and hnRNA was elevated in liver of zebrafish, but not for fabp10b and fabp11b. We also investigated the effect of dietary fatty acids (FAs) and clofibrate on the transcriptional regulation of single copy fabp genes, fabp2, fabp3 and fabp6 in zebrafish. The steady-state level of fabp2 transcripts increased in intestine, while fabp3 mRNA increased in liver of zebrafish fed diets differing in FA content. In zebrafish fed clofibrate, fabp3 mRNA in intestine, and fabp6 mRNA in intestine and heart, was elevated. Whether the regulation of fabp gene transcription by clofibrate is controlled either directly or indirectly, the regulatory elements in the zebrafish fabp genes have diverged markedly since the WGD event, thereby supporting the DDC model.

The fatty acid-binding protein (fabp) genes belong to the multigene family of intracellular lipid-binding proteins (iLBP). To date, 12 different FABPs have been identified in various vertebrate genomes. Owing to the fish-specific whole genome duplication (FSGD) event, many fishes have duplicated copies of the fabp genes. Here, I identified and characterized the fabp genes of spotted green pufferfish (Tetraodon nigroviridis). Initially, a BLAST search was performed and ten fabp genes were identified, out of which, three were retained in the pufferfish genome as duplicated copies. The putative pufferfish Fabp proteins shared greatest sequence identity and similarity with their teleost and tetrapod orthologs. Conserved gene synteny was evident between the pufferfish fabp genes and human, zebrafish, three-spined stickleback and medaka FABP/fabp genes, providing evidence that the duplicated copies of pufferfish fabp genes most likely arose as a result of the FSGD. The differential tissue-specific distribution of pufferfish fabp transcripts suggests divergent spatial regulation of duplicated pairs of fabp genes.

Hyperglycemia in critically ill patients was considered for many years an adaptive response to stress conditions being present in both patients with and without previous history of diabetes. Hyperglycemia is caused mainly by peripheral insulin resistance induced by the factors acting counteracting insulin signalling at the postreceptor level. Furthermore, hyperglycemia itself can then increase serum levels of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin-6 (Il-6) and interleukin-8 (Il- 8) and others. On the contrary, peripheral insulin resistance induced by pro- inflammatory cytokines may further potentiate hyperglycemia. White adipose tissue represents in addition to its energy storage function also a very active endocrine active organ. In addition to regulation of a number of metabolic processes it also significantly modulates the inflammatory response. In critically ill patients, adipose tissue changes its morphology, i.e. the adipocytes are shrinking and adipose tissue is abundantly infiltrated by macrophages. Paradoxically, overweight and obese critically ill patients have lower mortality than underweight, lean and morbidly obese subjects. In our studies, we selected population of the patients undergoing elective major cardiac surgery with extracorporeal...