Germ line mutations of the gene encoding the tricarboxylic acid (TCA) cycle enzyme fumarate hydratase (FH) cause a hereditary cancer syndrome known as hereditary leiomyomatosis and renal cell cancer (HLRCC). HLRCC-associated tumors harbor biallelic FH inactivation that results in the accumulation of the TCA cycle metabolite fumarate. Although it is known that fumarate accumulation can alter cellular signaling, if and how fumarate confers a growth advantage remain unclear. Here we show that fumarate accumulation confers a chronic proliferative signal by disrupting cellular iron signaling. Specifically, fumarate covalently modifies cysteine residues on iron regulatory protein 2 (IRP2), rendering it unable to repress ferritin mRNA translation. Simultaneously, fumarate increases ferritin gene transcription by activating the NRF2 (nuclear factor [erythroid-derived 2]-like 2) transcription factor. In turn, increased ferritin protein levels promote the expression of the promitotic transcription factor FOXM1 (Forkhead box protein M1). Consistently, clinical HLRCC tissues showed increased expression levels of both FOXM1 and its proliferation-associated target genes. This finding demonstrates how FH inactivation can endow cells with a growth advantage.

Introduction: Uterine fibroids are the most common benign tumours of female genital tract with the peak incidence in the 4th and 5th decennium. The aetiology of uterine fibroids still remains poorly understood. Genetic factors play undisputed role in the onset of uterine fibroids. Up to date numerous gene mutations were identified in certain percentage of patients with uterine fibroids. One of the candidate genes is Fumarate hydratase gene (FH). Heterozygous germiline mutations of FH cause two hereditary syndromes: Multiple smooth muscle tumours of the skin and uterus (MCUL1)/ Hereditary leiomyomatosis and renal cell cancer syndrome (HLRCC) characterised by leiomyomata of the skin, early onset uterine fibroids between 20-30 years of age and renal papillary carcinoma. The aim of our thesis was to identify the frequency of FH mutations in patients with early onset sporadic uterine fibroids. Methods: Patients with the diagnosis of uterine fibroids up to the age of 30 years were enrolled in the study. Control group consisted of patients with absence of uterine fibroids. Activities of Fumarate hydratase and control protein Citrate synthase were measured in lymphocytes and compared to the results obtained from the healthy controls. Mutation analysis of FH gene was performed. Activity of Fumarate...

Introduction: Uterine fibroids are the most common benign tumours of female genital tract with the peak incidence in the 4th and 5th decennium. The aetiology of uterine fibroids still remains poorly understood. Genetic factors play undisputed role in the onset of uterine fibroids. Up to date numerous gene mutations were identified in certain percentage of patients with uterine fibroids. One of the candidate genes is Fumarate hydratase gene (FH). Heterozygous germiline mutations of FH cause two hereditary syndromes: Multiple smooth muscle tumours of the skin and uterus (MCUL1)/ Hereditary leiomyomatosis and renal cell cancer syndrome (HLRCC) characterised by leiomyomata of the skin, early onset uterine fibroids between 20-30 years of age and renal papillary carcinoma. The aim of our thesis was to identify the frequency of FH mutations in patients with early onset sporadic uterine fibroids. Methods: Patients with the diagnosis of uterine fibroids up to the age of 30 years were enrolled in the study. Control group consisted of patients with absence of uterine fibroids. Activities of Fumarate hydratase and control protein Citrate synthase were measured in lymphocytes and compared to the results obtained from the healthy controls. Mutation analysis of FH gene was performed. Activity of Fumarate...

Glycoengineering is a technology that could improve protein therapeutics. While protein glycosylation in general enhances solubility and stability, and reduces aggregation, immunogenicity and proteolysis, specific kinds of glycosylation may also be critical. For example, capping of glycans with N-acetylneuraminic acid (Neu5Ac) maximises circulatory half-life in humans. Moreover, some glycans directly participate in molecular recognition and other aspects of glycoprotein function. Glycoproteins produced by non-human mammalian cells carry glycans capped by N-glycolyl-neuraminic acid rather than Neu5Ac. Yet production in human cell lines is costly and slow, requires specialist facilities, produces low yields and is subject to additional regulations. Hence there is a case for glycoengineering alternative expression systems capable of rapid, low-cost, high-yield glycoprotein production. This report focuses on the glycoengineering of Pichia pastoris, a yeast, to produce recombinant human glycoprotein factor H (FH) bearing human-like glycans. FH is a potent down-regulator of the complement system. Mutations and SNPs in FH result in autoimmune diseases such as atypical haemolytic ureamic syndrome and age-related macular degeneration (AMD). Recombinant FH is an enticing therapeutic candidate for treating AMD, but high doses are required since FH is abundant (200-300 mg l-1) in normal human serum. Human FH (155 kDa), with eight sites of N-linked glycosylation and 40 disulphides, is a challenging target for recombinant production. Yet FH was previously expressed to 10s of milligrams in P. pastoris. In this study, methods were established to confirm that human plasma-derived (h)FH carries predominantly N-linked diantennary disialylated complex-type glycans, with monosialylated diantennary structures and triantennary structures in fucosylated and non-fucosylated forms, contributing to glycan heterogeneity. Functional comparison of native hFH, enzymatically desialylated (DeSia-) hFH and deglycosylated recombinant P. pastoris-produced (DeGly-r)FH showed that DeSia-hFH had the lowest affinity for complement protein C3b, its key target. Moreover, DeSia-hFH binds C3d, an opsonic C3b-breakdown product, whereas native hFH does not. DeSia-hFH had an improved ability to accelerate decay of the C3 convertase (an enzyme that cleaves C3 to C3b) compared to native hFH, but neither was as good as DeGly-rFH in this respect. In contrast, DeGly-rFH had reduced cofactor activity (for factor I-mediated degradation of C3b) compared to native hFH whereas DeSiahFH did not have reduced cofactor activity. These data suggest that sialylation of FH glycans may play a role in stabilising a conformation of circulating FH that is not fully effective, consistent with specificity for self-surfaces and resistance to bacterial hijack. Aiming eventually to produce human-like glycosylated FH in glycoengineered P. pastoris, the SuperMan 5 strain served as a starting point. While conventional strains of P. pastoris put hypermannosylated N-linked glycans on proteins, glycans on SuperMan 5-produced FH were shown to contain just five mannose (Man) residues. In further glycoengineering, and following unsuccessful efforts to use inABLE technology for this purpose, commercially available (GlycoSwitch) vectors were used to introduce genes encoding the glycosyltransferase enzymes N-acetylglucosamine (GlcNAc) transferase I (GnTI) and galactose (Gal) transferase. These catalysed the formation of a hybrid-type glycan containing an N-acetyllactosamine (Gal-β(1,4)-GlcNAc (LacNAc)) antennae on a five-mannose glycan. Then two more GlycoSwitch plasmids, containing genes encoding α-Mannosidase II (ManII) and GnTII, were introduced into P. pastoris to catalyse the formation of a second LacNAc antennae. MALDI-TOF analysis found the glycosylation of this strain to be heterogeneous, containing the humanised diantennary digalactosyl glycan as well as other endogenous yeast glycans. This strain was designated SuperGal. Large-scale expression of rFH with terminally galactosylated complex-type glycans (Gal-rFH) in SuperGal yielded 100s of milligrams of purified Gal-rFH. Yeast-type glycans were enzymatically removed from rFH and the remaining complex-type humanised glycans were sialylated with a recombinant bacterial α(2,6)-sialyltransferase from Photobacterium sp. expressed in E.coli. Purified sialylated (Sia-) and non-sialylated (Gal-) rFH expressed in SuperGal were functionally characterised in vitro using SPR-based assays. In C3b-binding assays Sia-rFH had lower affinity compared to Gal-rFH. Both bound with lower affinity than DeGly-rFH. A similar pattern of binding affinity was seen for C3d. In C3 convertase decay-acceleration assays, all rFH glycoforms performed equally well and had greater activity than hFH. Conversely, Sia-and Gal-rFH were shown to perform equally as well as hFH in CA assays, while all three versions outperformed DeGly-rFH. However, in vivo complement activity assay carried out in a FH-knockout mouse model showed that humanisation of the glycosylation of rFH did not significantly improve activity compared to DeGly-rFH. In addition, analysis of the circulatory half-life of rFH showed that humanisation did not improve half-life. Further engineering steps will be required to increase the complex-type glycan site occupancy on rFH with a view to improving circulatory half-life and efficacy. However, this study represents a significant step forward in developing a therapeutically useful source of rFH.

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / The ISM bands have opened up new opportunities for telemetry using spread-spectrum communications. A low-cost frequency-hopping radio is described here for the 900 MHz ISM band that can be programmed with a wide range of hop and data rates. The ‘C6201 DSP from TI is used to control the frequency and data rate of the TI TRF6900 transceiver chip using a custom interface of the 6201 EVM board to the serial I/O on the 6900 evaluation board.

L’hypercholestérolémie familiale (FH) est un désordre lipidique associé aux maladies cardiovasculaires les plus fréquentes. La FH est causée par des mutations dans les gènes LDLR, APOB et PCSK9. Toutefois, chez 20% des patients souffrant de FH, aucune mutation dans ces gènes n'a été détectée et ceci suggère que d’autres gènes seraient à l’origine de la FH. Actuellement, le seul traitement de la FH est une thérapie aux statines. En général les statines sont bien tolérées, cependant, une monothérapie ne permet pas d’atteindre des niveaux thérapeutiques acceptables et dans bien des cas, une thérapie combinée devient nécessaire. De plus, l’intolérance aux statines est présente dans environ 12% des patients. Dans les trois dernières décennies, la survie des patients avec la FH a augmentée de façon notoire mais on observe aussi l’apparition d’une calcification vasculaire sévère chez certains d’entre eux. Il est donc primordial de développer des nouvelles approches thérapeutiques afin de prévenir ces complications tardives. Dans cette thèse doctorat, nous présentons l’étude d’une famille avec un phénotype de FH sévère non causé par des mutations dans les gènes LDLR, APOB et PCSK9. Par des études biochimiques et par séquençage d’ADN utilisant les technologies de nouvelle génération (NextGenSeq), nous avons découvert une mutation dans le gène de l’APOE (Leu167del). Ceci nous permet de proposer le gène codant pour l’APOE comme le 4e locus responsable de la FH (FH4). Par la suite, nous avons effectué deux études de cohortes chez les patients atteints de FH. Premièrement, dans l’étude JUPITER, nous avons démontré que la rosuvastatin augmente les niveaux sanguins de la protéine PCSK9 et ceci limiterait l’efficacité du traitement aux statines. Nous avons aussi étudié l’influence du mutant naturel R46L (perte de fonction de la PCSK9) dans la réponse aux statines. Deuxièmement, nous avons examiné les effets de la perte de fonction de la PCSK9 sur le profil cardiométabolique au sein d’une population pédiatrique. Nous avons déterminé que le génotype de l’APOE est déterminant dans ce profil cardiométabolique. Enfin, nous avons étudié la calcification vasculaire chez les patients atteints de FH. Cette calcification vasculaire progresse de façon indépendante des niveaux de cholestérol sérique et n’est pas associée aux anomalies de l’homéostasie du calcium. En utilisant des modèles murins, nous avons démontré que les souris Ldlr-/- et Tg(Pcsk9) développent des calcifications vasculaires semblables à celles observées chez l’homme. De plus, nous avons confirmé l’implication de la voie de signalisation LRP5/Wnt dans la pathophysiologie de la calcification artérielle. Avec une étude interventionnelle, nous avons trouvé que l’inhibition de l’interleukine 1β (IL-1β) diminue fortement l’apparition de calcifications vasculaire dans notre modèle murin. En conclusion, nos études ont permis l’identification d’un nouveau gène impliqué dans la FH, ont démontré aussi que les statines augmentent les niveaux sériques de PCSK9 et que la perte de fonction de la PCSK9 altère le profil cardiométabolique. Enfin, nous avons établi que la calcification vasculaire représente une complication tardive chez les patients atteints de FH et que, dans notre modèle murin, la calcification vasculaire peut être retardée par l’inhibition d’IL-1β. Ces découvertes peuvent avoir d’importantes répercussions cliniques chez l’humain. / Familial Hypercholesterolemia (FH) is the most common lipoprotein disorder associated with premature cardiovascular disease. Mutations in the LDLR, APOB and PCSK9 genes cause the FH phenotype, but in 20% of FH patients, no mutations in these genes are identified, suggesting that mutations in other genes cause FH. Treatment with statins has been the cornerstone of therapy. While statins are generally well tolerated, statin intolerance is found in approximately 12% of patients. Furthermore, statin use may not allow reaching LDL-C goals and combination therapy is often required. Nevertheless, survival of FH patients over the past 3 decades has improved significantly. As FH patients live longer, severe vascular calcifications have been described as a late complication in these patients. Given the increased survival rate and late complications, novel approaches and therapies are needed. In the present thesis we examined a kindred with a severe FH phenotype, where sequencing of candidate genes failed to identify a causal mutation. Through biochemical analysis and next-generation exome sequencing we report a mutation (Leu167del) within the APOE gene that identifies the 4th locus causing FH (FH4). Next, we performed two cohort-based studies. Firstly, in the JUPITER trial we report that 20mg rosuvastatin treatment increases PCSK9 levels by 30%, thereby possibly limiting the efficacy of statin therapy. Then we show the effect of a loss-of-function (LOF) mutation of PCSK9, p.R46L, on the response to rosuvastatin. Secondly, we report that two PCSK9 gene variants, p.R46L and insLEU, were more frequent in French Canadian individuals. We also report that the APOE genotype determine the metabolic risk profile in these mutations. Finally, we studied vascular calcifications in FH individuals. These calcifications appear to progress independently of cholesterol levels and are not associated with disturbances in calcium homeostasis. Using mouse models, we show that Ldlr-/- and Tg(Pcsk9) mice develop aortic calcifications similar to that observed in humans. Furthermore, the involvement of the LRP5/Wnt pathway in the pathogenesis of calcification is illustrated. In a proof-of-concept experiment, inhibiting the upstream pro-inflammatory cytokine IL-1β attenuates calcification in mice. In conclusion, we have contributed to the identification of a novel locus responsible for FH, reported the increase in PCSK9 levels with a statins treatment and the associated altered cardiometabolic profile in PCSK9 LOF. Finally, we demonstrated that vascular calcifications represent a severe complication of FH that can be prevented by inhibiting IL-1β in a mouse model. The latter novel approach may have an important translational application in human.

L’hypercholestérolémie familiale (FH) est un désordre lipidique associé aux maladies cardiovasculaires les plus fréquentes. La FH est causée par des mutations dans les gènes LDLR, APOB et PCSK9. Toutefois, chez 20% des patients souffrant de FH, aucune mutation dans ces gènes n'a été détectée et ceci suggère que d’autres gènes seraient à l’origine de la FH. Actuellement, le seul traitement de la FH est une thérapie aux statines. En général les statines sont bien tolérées, cependant, une monothérapie ne permet pas d’atteindre des niveaux thérapeutiques acceptables et dans bien des cas, une thérapie combinée devient nécessaire. De plus, l’intolérance aux statines est présente dans environ 12% des patients. Dans les trois dernières décennies, la survie des patients avec la FH a augmentée de façon notoire mais on observe aussi l’apparition d’une calcification vasculaire sévère chez certains d’entre eux. Il est donc primordial de développer des nouvelles approches thérapeutiques afin de prévenir ces complications tardives. Dans cette thèse doctorat, nous présentons l’étude d’une famille avec un phénotype de FH sévère non causé par des mutations dans les gènes LDLR, APOB et PCSK9. Par des études biochimiques et par séquençage d’ADN utilisant les technologies de nouvelle génération (NextGenSeq), nous avons découvert une mutation dans le gène de l’APOE (Leu167del). Ceci nous permet de proposer le gène codant pour l’APOE comme le 4e locus responsable de la FH (FH4). Par la suite, nous avons effectué deux études de cohortes chez les patients atteints de FH. Premièrement, dans l’étude JUPITER, nous avons démontré que la rosuvastatin augmente les niveaux sanguins de la protéine PCSK9 et ceci limiterait l’efficacité du traitement aux statines. Nous avons aussi étudié l’influence du mutant naturel R46L (perte de fonction de la PCSK9) dans la réponse aux statines. Deuxièmement, nous avons examiné les effets de la perte de fonction de la PCSK9 sur le profil cardiométabolique au sein d’une population pédiatrique. Nous avons déterminé que le génotype de l’APOE est déterminant dans ce profil cardiométabolique. Enfin, nous avons étudié la calcification vasculaire chez les patients atteints de FH. Cette calcification vasculaire progresse de façon indépendante des niveaux de cholestérol sérique et n’est pas associée aux anomalies de l’homéostasie du calcium. En utilisant des modèles murins, nous avons démontré que les souris Ldlr-/- et Tg(Pcsk9) développent des calcifications vasculaires semblables à celles observées chez l’homme. De plus, nous avons confirmé l’implication de la voie de signalisation LRP5/Wnt dans la pathophysiologie de la calcification artérielle. Avec une étude interventionnelle, nous avons trouvé que l’inhibition de l’interleukine 1β (IL-1β) diminue fortement l’apparition de calcifications vasculaire dans notre modèle murin. En conclusion, nos études ont permis l’identification d’un nouveau gène impliqué dans la FH, ont démontré aussi que les statines augmentent les niveaux sériques de PCSK9 et que la perte de fonction de la PCSK9 altère le profil cardiométabolique. Enfin, nous avons établi que la calcification vasculaire représente une complication tardive chez les patients atteints de FH et que, dans notre modèle murin, la calcification vasculaire peut être retardée par l’inhibition d’IL-1β. Ces découvertes peuvent avoir d’importantes répercussions cliniques chez l’humain. / Familial Hypercholesterolemia (FH) is the most common lipoprotein disorder associated with premature cardiovascular disease. Mutations in the LDLR, APOB and PCSK9 genes cause the FH phenotype, but in 20% of FH patients, no mutations in these genes are identified, suggesting that mutations in other genes cause FH. Treatment with statins has been the cornerstone of therapy. While statins are generally well tolerated, statin intolerance is found in approximately 12% of patients. Furthermore, statin use may not allow reaching LDL-C goals and combination therapy is often required. Nevertheless, survival of FH patients over the past 3 decades has improved significantly. As FH patients live longer, severe vascular calcifications have been described as a late complication in these patients. Given the increased survival rate and late complications, novel approaches and therapies are needed. In the present thesis we examined a kindred with a severe FH phenotype, where sequencing of candidate genes failed to identify a causal mutation. Through biochemical analysis and next-generation exome sequencing we report a mutation (Leu167del) within the APOE gene that identifies the 4th locus causing FH (FH4). Next, we performed two cohort-based studies. Firstly, in the JUPITER trial we report that 20mg rosuvastatin treatment increases PCSK9 levels by 30%, thereby possibly limiting the efficacy of statin therapy. Then we show the effect of a loss-of-function (LOF) mutation of PCSK9, p.R46L, on the response to rosuvastatin. Secondly, we report that two PCSK9 gene variants, p.R46L and insLEU, were more frequent in French Canadian individuals. We also report that the APOE genotype determine the metabolic risk profile in these mutations. Finally, we studied vascular calcifications in FH individuals. These calcifications appear to progress independently of cholesterol levels and are not associated with disturbances in calcium homeostasis. Using mouse models, we show that Ldlr-/- and Tg(Pcsk9) mice develop aortic calcifications similar to that observed in humans. Furthermore, the involvement of the LRP5/Wnt pathway in the pathogenesis of calcification is illustrated. In a proof-of-concept experiment, inhibiting the upstream pro-inflammatory cytokine IL-1β attenuates calcification in mice. In conclusion, we have contributed to the identification of a novel locus responsible for FH, reported the increase in PCSK9 levels with a statins treatment and the associated altered cardiometabolic profile in PCSK9 LOF. Finally, we demonstrated that vascular calcifications represent a severe complication of FH that can be prevented by inhibiting IL-1β in a mouse model. The latter novel approach may have an important translational application in human.

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Im vogtländischen Musikwinkel und in direkter Nachbarschaft zu Bayern und Tschechien gelegen, befindet sich die kleinste Zweigbibliothek des Bibliothekssystems der Westsächsischen Hochschule Zwickau. Wer von Zwickau kommend nach etwa 60 Kilometern Markneukirchen erreicht, trifft nach wenigen 100 Metern auf eine sehr schön restaurierte Jugendstilvilla, die sogenannte Merz-Villa. Von außen verrät das Gebäude nicht sofort seine Bestimmung als Ausbildungsstandort für den Studiengang Musikinstrumentenbau der Westsächsischen Hochschule Zwickau mit seiner kleinen, feinen Bibliothek.

Background: Familial hypercholesterolemia (FH) is a genetic disorder estimated to affect 0,4 % of the world's population (1 in 250). Patients with FH have abnormally high LDL-cholesterol.  Aim: The aim of this study was to estimate the prevalence of FH in Stockholm County and to evaluate the health economic impact of diagnosing people with FH early in life. Methods: Two algorithms were used to estimate the number of people with high LDLcholesterol. The first method applied data on cholesterol measurements from patients in Stockholm County between 2006-2008 and a modified version of Dutch Lipid Clinic Network. The second method was based on dispensed prescriptions of ezetimibe, lomitapide, evolucumab and alirocumab during 2019. A health economic model was created to estimate the economical outcome of diagnosing and treating patients early before undergoing a cardiovascular event. Results: The prevalence of FH in Stockholm County was estimated to 0.63 %, corresponding to a total of 12 000 individuals. The accumulated costs over 20 years for FH is estimated to be more than 1,1 billion SEK for diagnosed and treated patients, and 1,7 billion SEK for undiagnosed and untreated patients. Conclusions: The prevalence of FH in Stockholm County is probably higher than previously suggested. Early diagnosis and treatment is an investment for society and necessary for the patients to prevent cardiovascular events and improve quality of life.