@phdthesis{Gibert2021, author = {Gibert, Arthur}, title = {Influence of Amyloid Aggregates on the Trafficking and Signaling of GPCRs}, doi = {10.25932/publishup-50665}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-506659}, school = {Universit{\"a}t Potsdam}, pages = {100}, year = {2021}, abstract = {The prevalence of diseases associated with misfolded proteins increases with age. When cellular defense mechanisms become limited, misfolded proteins form aggregates and may also develop more stable cross-β structures ultimately forming amyloid aggregates. Amyloid aggregates are associated with neurodegenerative diseases such as Alzheimer's disease and Huntington's disease. The formation of amyloid deposits, their toxicity and cellular defense mechanisms have been intensively studied. However, surprisingly little is known about the effects of protein aggregates on cellular signal transduction. It is also not understood whether the presence of aggregation-prone, but still soluble proteins affect signal transduction. In this study, the still soluble aggregation-prone HttExon1Q74 and its amyloid aggregates were used to analyze the effect of amyloid aggregates on internalization and receptor activation of G protein-coupled receptors (GPCRs), the largest protein family of mammalian cell surface receptors involved in signal transduction. The aggregated HttExon1Q74, but not its soluble form, could inhibit ligand-induced clathrin-mediated endocytosis (CME) of various GPCRs. Most likely this inhibitory effect is based on a terminal sequestration of the HSC70 chaperone to the aggregates which is necessary for CME. Using the vasopressinV1a receptor (V1aR) and the corticotropin-releasing factor receptor 1 (CRF1R) as a model, it could be shown that the presence of HttExon1Q74 aggregates and the inhibition of ligand-induced CME leads to an accumulation of desensitized receptors at the plasma membrane. In turn, this disrupts Gq-mediated Ca2+ signaling and Gs-mediated cAMP signaling of the V1aR and the CRF1R respectively. In contrast to HttExon1Q74 amyloid aggregates, soluble HttExon1Q74 as well as amorphous aggregates did not inhibit GPCR internalization and signaling demonstrating that cellular signal transduction mechanisms are specifically impaired in response to the formation of amyloid aggregates. In addition, preliminary experiments could show that HttExon1Q74 aggregates provoke an increase in membrane expression of a protein from a structurally and functionally unrelated membrane protein family, namely the serotonin transporter SERT. As SERT is the main pharmacological target to treat depression this could shed light on this commonly occurring comorbidity in neurodegenerative diseases, in particular in early disease states.}, language = {en} } @article{EnssleWeylandt2021, author = {Enssle, J{\"o}rg and Weylandt, Karsten-Henrich}, title = {Secure and optimized detection of PNPLA3 rs738409 genotype by an improved PCR-restriction fragment length polymorphism method}, series = {BioTechniques : the international journal of life science methods}, volume = {70}, journal = {BioTechniques : the international journal of life science methods}, number = {6}, publisher = {Future Science Ltd.}, address = {London}, issn = {0736-6205}, doi = {10.2144/btn-2020-0163}, pages = {345 -- 349}, year = {2021}, abstract = {The PNPLA3 reference single-nucleotide polymorphism rs738409 has been identified as a predisposing factor for nonalcoholic fatty liver disease. A simple method based on PCR and restriction fragment length polymorphism (RFLP) analysis had been published to detect the nonpathogenic allele PNPLA3 rs738409 variant. The presence of the pathogenic variant was deduced by the indigestibility of the corresponding PCR product with BtsCI recognizing the nonpathogenic allele. However, one cannot exclude that an enzymatic reaction does not occur for other, more trivial, reasons. For safe and secure detection of the pathogenic PNPLA3 rs738409, we have further developed the PCR-restriction fragment length polymorphism method by adding a second restriction enzyme digest, clearly identifying the correct PNPLA3 alleles and in particular the pathogenic variant.
METHOD SUMMARY
The method presented here represents an improved genetic diagnosis of the PNPLA3 rs738409 alleles based on conventional and inexpensive molecular biological methods. We used methodology based on PCR and restriction fragment length polymorphisms and clearly identified both described alleles by the use of two restriction enzymes. Digestion of individuals' specific PNPLA3 PCR fragments with both enzymes in independent reactions clearly showed the PNPLA3 rs738409 genotype.}, language = {en} } @article{LiStomaLottaetal.2020, author = {Li, Chen and Stoma, Svetlana and Lotta, Luca A. and Warner, Sophie and Albrecht, Eva and Allione, Alessandra and Arp, Pascal P. and Broer, Linda and Buxton, Jessica L. and Boeing, Heiner and Langenberg, Claudia and Codd, Veryan}, title = {Genome-wide association analysis in humans links nucleotide metabolism to leukocyte telomere length}, series = {American Journal of Human Genetics}, volume = {106}, journal = {American Journal of Human Genetics}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, pages = {16}, year = {2020}, abstract = {Leukocyte telomere length (LTL) is a heritable biomarker of genomic aging. In this study, we perform a genome-wide meta-analysis of LTL by pooling densely genotyped and imputed association results across large-scale European-descent studies including up to 78,592 individuals. We identify 49 genomic regions at a false dicovery rate (FDR) < 0.05 threshold and prioritize genes at 31, with five highlighting nucleotide metabolism as an important regulator of LTL. We report six genome-wide significant loci in or near SENP7, MOB1B, CARMIL1 , PRRC2A, TERF2, and RFWD3, and our results support recently identified PARP1, POT1, ATM, and MPHOSPH6 loci. Phenome-wide analyses in >350,000 UK Biobank participants suggest that genetically shorter telomere length increases the risk of hypothyroidism and decreases the risk of thyroid cancer, lymphoma, and a range of proliferative conditions. Our results replicate previously reported associations with increased risk of coronary artery disease and lower risk for multiple cancer types. Our findings substantially expand current knowledge on genes that regulate LTL and their impact on human health and disease.}, language = {en} } @misc{LiStomaLottaetal.2020, author = {Li, Chen and Stoma, Svetlana and Lotta, Luca A. and Warner, Sophie and Albrecht, Eva and Allione, Alessandra and Arp, Pascal P. and Broer, Linda and Buxton, Jessica L. and Boeing, Heiner and Langenberg, Claudia and Codd, Veryan}, title = {Genome-wide association analysis in humans links nucleotide metabolism to leukocyte telomere length}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {3}, issn = {1866-8372}, doi = {10.25932/publishup-52684}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-526843}, pages = {18}, year = {2020}, abstract = {Leukocyte telomere length (LTL) is a heritable biomarker of genomic aging. In this study, we perform a genome-wide meta-analysis of LTL by pooling densely genotyped and imputed association results across large-scale European-descent studies including up to 78,592 individuals. We identify 49 genomic regions at a false dicovery rate (FDR) < 0.05 threshold and prioritize genes at 31, with five highlighting nucleotide metabolism as an important regulator of LTL. We report six genome-wide significant loci in or near SENP7, MOB1B, CARMIL1 , PRRC2A, TERF2, and RFWD3, and our results support recently identified PARP1, POT1, ATM, and MPHOSPH6 loci. Phenome-wide analyses in >350,000 UK Biobank participants suggest that genetically shorter telomere length increases the risk of hypothyroidism and decreases the risk of thyroid cancer, lymphoma, and a range of proliferative conditions. Our results replicate previously reported associations with increased risk of coronary artery disease and lower risk for multiple cancer types. Our findings substantially expand current knowledge on genes that regulate LTL and their impact on human health and disease.}, language = {en} } @misc{OttoMareljaSchoofsetal.2018, author = {Otto, Nils and Marelja, Zvonimir and Schoofs, Andreas and Kranenburg, Holger and Bittern, Jonas and Yildirim, Kerem and Berh, Dimitri and Bethke, Maria and Thomas, Silke and Rode, Sandra and Risse, Benjamin and Jiang, Xiaoyi and Pankratz, Michael and Leimk{\"u}hler, Silke and Kl{\"a}mbt, Christian}, title = {The sulfite oxidase Shopper controls neuronal activity by regulating glutamate homeostasis in Drosophila ensheathing glia}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {975}, issn = {1866-8372}, doi = {10.25932/publishup-42620}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426205}, pages = {14}, year = {2018}, abstract = {Specialized glial subtypes provide support to developing and functioning neural networks. Astrocytes modulate information processing by neurotransmitter recycling and release of neuromodulatory substances, whereas ensheathing glial cells have not been associated with neuromodulatory functions yet. To decipher a possible role of ensheathing glia in neuronal information processing, we screened for glial genes required in the Drosophila central nervous system for normal locomotor behavior. Shopper encodes a mitochondrial sulfite oxidase that is specifically required in ensheathing glia to regulate head bending and peristalsis. shopper mutants show elevated sulfite levels affecting the glutamate homeostasis which then act on neuronal network function. Interestingly, human patients lacking the Shopper homolog SUOX develop neurological symptoms, including seizures. Given an enhanced expression of SUOX by oligodendrocytes, our findings might indicate that in both invertebrates and vertebrates more than one glial cell type may be involved in modulating neuronal activity.}, language = {en} } @misc{HenkelColemanMacGregorofInneregnySchraplauetal.2018, author = {Henkel, Janin and Coleman Mac Gregor of Inneregny, Charles Dominic and Schraplau, Anne and J{\"o}hrens, Korinna and Weiss, Thomas Siegfried and Jonas, Wenke and Sch{\"u}rmann, Annette and P{\"u}schel, Gerhard Paul}, title = {Augmented liver inflammation in a microsomal prostaglandin E synthase 1 (mPGES-1)-deficient diet-induced mouse NASH model}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {483}, issn = {1866-8372}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-420879}, pages = {11}, year = {2018}, abstract = {In a subset of patients, non-alcoholic fatty liver disease (NAFLD) is complicated by cell death and inflammation resulting in non-alcoholic steatohepatitis (NASH), which may progress to fibrosis and subsequent organ failure. Apart from cytokines, prostaglandins, in particular prostaglandin E-2 (PGE(2)), play a pivotal role during inflammatory processes. Expression of the key enzymes of PGE(2) synthesis, cyclooxygenase 2 and microsomal PGE synthase 1 (mPGES-1), was increased in human NASH livers in comparison to controls and correlated with the NASH activity score. Both enzymes were also induced in NASH-diet-fed wild-type mice, resulting in an increase in hepatic PGE(2) concentration that was completely abrogated in mPGES-1-deficient mice. PGE(2) is known to inhibit TNF-alpha synthesis in macrophages. A strong infiltration of monocyte-derived macrophages was observed in NASH-diet-fed mice, which was accompanied with an increase in hepatic TNF-alpha expression. Due to the impaired PGE(2) production, TNF-alpha expression increased much more in livers of mPGES-1-deficient mice or in the peritoneal macrophages of these mice. The increased levels of TNF-alpha resulted in an enhanced IL-1 beta production, primarily in hepatocytes, and augmented hepatocyte apoptosis. In conclusion, attenuation of PGE(2) production by mPGES-1 ablation enhanced the TNF-alpha-triggered inflammatory response and hepatocyte apoptosis in diet-induced NASH.}, language = {en} } @article{HenkelColemanMacGregorofInneregnySchraplauetal.2018, author = {Henkel, Janin and Coleman Mac Gregor of Inneregny, Charles Dominic and Schraplau, Anne and J{\"o}hrens, Korinna and Weiss, Thomas Siegfried and Jonas, Wenke and Sch{\"u}rmann, Annette and P{\"u}schel, Gerhard Paul}, title = {Augmented liver inflammation in a microsomal prostaglandin E synthase 1 (mPGES-1)-deficient diet-induced mouse NASH model}, series = {Scientific Reports}, journal = {Scientific Reports}, number = {8}, publisher = {Nature Research}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-018-34633-y}, pages = {1 -- 11}, year = {2018}, abstract = {In a subset of patients, non-alcoholic fatty liver disease (NAFLD) is complicated by cell death and inflammation resulting in non-alcoholic steatohepatitis (NASH), which may progress to fibrosis and subsequent organ failure. Apart from cytokines, prostaglandins, in particular prostaglandin E-2 (PGE(2)), play a pivotal role during inflammatory processes. Expression of the key enzymes of PGE(2) synthesis, cyclooxygenase 2 and microsomal PGE synthase 1 (mPGES-1), was increased in human NASH livers in comparison to controls and correlated with the NASH activity score. Both enzymes were also induced in NASH-diet-fed wild-type mice, resulting in an increase in hepatic PGE(2) concentration that was completely abrogated in mPGES-1-deficient mice. PGE(2) is known to inhibit TNF-alpha synthesis in macrophages. A strong infiltration of monocyte-derived macrophages was observed in NASH-diet-fed mice, which was accompanied with an increase in hepatic TNF-alpha expression. Due to the impaired PGE(2) production, TNF-alpha expression increased much more in livers of mPGES-1-deficient mice or in the peritoneal macrophages of these mice. The increased levels of TNF-alpha resulted in an enhanced IL-1 beta production, primarily in hepatocytes, and augmented hepatocyte apoptosis. In conclusion, attenuation of PGE(2) production by mPGES-1 ablation enhanced the TNF-alpha-triggered inflammatory response and hepatocyte apoptosis in diet-induced NASH.}, language = {en} } @misc{ChaykovskaHeunischvonEinemetal.2016, author = {Chaykovska, Lyubov and Heunisch, Fabian and von Einem, Gina and Alter, Markus L. and Hocher, Carl-Friedrich and Tsuprykov, Oleg and Dschietzig, Thomas and Kretschmer, Axel and Hocher, Berthold}, title = {Urinary vitamin D binding protein and KIM-1 are potent new biomarkers of major adverse renal events in patients undergoing coronary angiography}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {558}, issn = {1866-8372}, doi = {10.25932/publishup-41192}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-411928}, pages = {11}, year = {2016}, abstract = {Background Vitamin-D-binding protein (VDBP) is a low molecular weight protein that is filtered through the glomerulus as a 25-(OH) vitamin D 3/VDBP complex. In the normal kidney VDBP is reabsorbed and catabolized by proximal tubule epithelial cells reducing the urinary excretion to trace amounts. Acute tubular injury is expected to result in urinary VDBP loss. The purpose of our study was to explore the potential role of urinary VDBP as a biomarker of an acute renal damage. Method We included 314 patients with diabetes mellitus or mild renal impairment undergoing coronary angiography and collected blood and urine before and 24 hours after the CM application. Patients were followed for 90 days for the composite endpoint major adverse renal events (MARE: need for dialysis, doubling of serum creatinine after 90 days, unplanned emergency rehospitalization or death). Results Increased urine VDBP concentration 24 hours after contrast media exposure was predictive for dialysis need (no dialysis: 113.06 +/- 299.61ng/ml, n = 303; need for dialysis: 613.07 +/- 700.45 ng/ml, n = 11, Mean +/- SD, p < 0.001), death (no death during follow-up: 121.41 +/- 324.45 ng/ml, n = 306; death during follow-up: 522.01 +/- 521.86 ng/ml, n = 8; Mean +/- SD, p < 0.003) and MARE (no MARE: 112.08 +/- 302.00ng/ml, n = 298; MARE: 506.16 +/- 624.61 ng/ml, n = 16, Mean +/- SD, p < 0.001) during the follow-up of 90 days after contrast media exposure. Correction of urine VDBP concentrations for creatinine excretion confirmed its predictive value and was consistent with increased levels of urinary Kidney Injury Molecule1 (KIM-1) and baseline plasma creatinine in patients with above mentioned complications. The impact of urinary VDBP and KIM-1 on MARE was independent of known CIN risk factors such as anemia, preexisting renal failure, preexisting heart failure, and diabetes. Conclusions Urinary VDBP is a promising novel biomarker of major contrast induced nephropathy-associated events 90 days after contrast media exposure.}, language = {en} } @article{HenzeHomannRohnetal.2016, author = {Henze, Andrea and Homann, Thomas and Rohn, Isabelle and Aschner, Michael A. and Link, Christopher D. and Kleuser, Burkhard and Schweigert, Florian J. and Schwerdtle, Tanja and Bornhorst, Julia}, title = {Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep37346}, pages = {12}, year = {2016}, abstract = {The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time- and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization - time of flight - mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.}, language = {en} } @misc{HenzeHomannRohnetal.2016, author = {Henze, Andrea and Homann, Thomas and Rohn, Isabelle and Aschner, Michael A. and Link, Christopher D. and Kleuser, Burkhard and Schweigert, Florian J. and Schwerdtle, Tanja and Bornhorst, Julia}, title = {Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-103674}, pages = {12}, year = {2016}, abstract = {The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time- and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization - time of flight - mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.}, language = {en} }