Hannover, Universiẗat, Diss., 2000.

Proefschrift Universiteit van Amsterdam. / Met lit. opg. - Met samenvatting in het Nederlands.

Inflammatory and neuropathic pains arise in part from sensitization at nociceptive synapses in the spinal cord. Activity-dependent signaling cascades converge onto the tyrosine kinase Src, which participates in augmenting the function of N-methyl-D-aspartate receptors (NMDARs) and thus potentiates the nociceptive system. Src is capable of these effects because it is anchored to the NMDAR complex via an adaptor protein called NADH dehydrogenase subunit 2 (ND2). There is evidence that this interaction occurs between amino acids 40-49 of Src and amino acids 310-321 of ND2. I have determined that a peptide consisting of amino acids 310-321 of ND2, and affixed to the HIV Tat domain for cell permeability, is capable of alleviating tactile allodynia induced by Complete Freund's Adjuvant (CFA) in rats. Src40-49Tat was not effective in two models of inflammatory pain. This work further implicates the Src-ND2 interaction in pain hypersensitivity and suggests that Tat ND2 310-321 may alleviate it.

Inflammatory and neuropathic pains arise in part from sensitization at nociceptive synapses in the spinal cord. Activity-dependent signaling cascades converge onto the tyrosine kinase Src, which participates in augmenting the function of N-methyl-D-aspartate receptors (NMDARs) and thus potentiates the nociceptive system. Src is capable of these effects because it is anchored to the NMDAR complex via an adaptor protein called NADH dehydrogenase subunit 2 (ND2). There is evidence that this interaction occurs between amino acids 40-49 of Src and amino acids 310-321 of ND2. I have determined that a peptide consisting of amino acids 310-321 of ND2, and affixed to the HIV Tat domain for cell permeability, is capable of alleviating tactile allodynia induced by Complete Freund's Adjuvant (CFA) in rats. Src40-49Tat was not effective in two models of inflammatory pain. This work further implicates the Src-ND2 interaction in pain hypersensitivity and suggests that Tat ND2 310-321 may alleviate it.

University, Diss., 2004--Frankfurt (Main). / Zsfassung in engl. und dt. Sprache.

University, Diss., 2005--Frankfurt (Main). / Zsfassung in engl. und dt. Sprache.

Universiẗat, Diss., 2001--Frankfurt (Main).

Univ., Diss., 2008--Frankfurt (Main).

Abstract Human mitochondria contain a circular genome called mitochondrial DNA (mtDNA). It encodes subunits of the respiratory chain enzymes involved in energy conservation in oxidative phosphorylation and the necessary RNA needed for their expression. Errors in these genes have been shown to cause diseases, called mitochondrial diseases, which mainly affect tissues with high energy-demand, such as brain, heart, and skeletal muscle, or to lead to the production of harmful by-products in the form of reactive oxygen species (ROS) during cellular respiration. ROS damage lipids, proteins, and DNA, especially mtDNA. Accumulation of mtDNA mutations has also been associated with aging. Mitochondrial complex I is located in the inner mitochondrial membrane and catalyzes NADH-ubiquinone oxidoreduction coupled to the translocation of four protons from the inside of the mitochondrion to the intermembranous space. Bacteria contain a homologous but simpler enzyme, NDH-1, with the same catalytic mechanism and which is therefore considered the catalytical core of mitochondrial complex I. Seven of the conserved membranous subunits in complex I are encoded in the mtDNA and are targets for mutations causing mitochondrial diseases, like MELAS syndrome or Leber hereditary optic neuropathy (LHON). We used Paracoccus denitrificans and Escherichia coli NDH-1 enzymes to reveal the role of selected conserved charged residues and MELAS or LHON amino acid substitutions in enzyme catalysis. The growth phenotypes and NDH-1-dependent activities in mutant bacterial membranes were characterized, in addition to the sensitivity to selected complex I inhibitors. In order to enable ROS production measurements in the bacterial model of human mitochondrial diseases, we evaluated the reliability of two superoxide detecting probes, lucigenin and coelenterazine. Elimination of the acidic residue in ND1 (position E228) previously found to cause MELAS, was found detrimental for NDH-1 assembly and activity. Also, elimination of the acidic residue at position E36 in ND4L resulted in an inactive enzyme. ND1-E216A, ND4L-E72Q and -E36Q/I39D/A69D/E72Q substitutions decreased NDH-1 activity somewhat (normal activity in the last mutant), but displayed a negative growth phenotype under NDH-1 dependent conditions, suggestive of impaired energy conservation in these mutants. ND1-Y229, whose substitution causes MELAS, charged residues in loop five of ND1, and ND1-E157, whose substitution causes LHON, were also found important for the enzyme activity. Coelenterazine was found a reliable probe for quantitative superoxide production measurement in mitochondrial or bacterial membranes, and its sensitivity is not affected by the reduction level of the respiratory chain. Therefore, coelenterazine is suitable for quantitative superoxide production measurements.

No description available.