@phdthesis{Tauscher2020,
  author    = {Tauscher, Sabine Christine},
  title     = {Die Rolle von Atrialen und B-Typ Natriuretischen Peptiden bei der Regulation der Insulinsekretion und Funktion pankreatischer ß-Zellen},
  doi       = {10.25972/OPUS-20842},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-208427},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {Die kardialen Hormone Atriales (ANP) und B-Typ (BNP) Natriuretisches Peptid {\"u}ben bekannte renale und kardiovaskul{\"a}re Effekte aus, welche durch ihren gemeinsamen, cGMP-bildenden Guanylatzyklase-Rezeptor A (GC-A) vermittelt werden. Diese Effekte sind entscheidend an der physiologischen Aufrechterhaltung des arteriellen Blutdrucks sowie des intravaskul{\"a}ren Blutvolumens beteiligt. Dar{\"u}ber hinaus zeigen aktuelle Studien, dass NPs die Mobilisierung von Fetts{\"a}uren aus dem Fettgewebe und deren Oxidation durch die Skelettmuskulatur steigern sowie die Thermogenese in braunem und weißem Fettgewebe aktivieren k{\"o}nnen. Dadurch k{\"o}nnen NPs den Energieverbrauch erh{\"o}hen und die Insulinsensitivit{\"a}t verbessern. Desweiteren ist {\"U}bergewicht mit einer gest{\"o}rten NP/GC-A/cGMP-Signal{\"u}bertragung verbunden, die m{\"o}glicherweise zur Entwicklung von Diabetes Typ 2 und dessen kardio-metabolischen Folgeerkrankungen beitr{\"a}gt. In vitro stimuliert synthetisches ANP {\"u}ber GC-A die Glukose-stimulierte Insulinsekretion aus kultivierten pankreatischen Inseln und die β-Zellproliferation. Die Bedeutung f{\"u}r die systemische Insulin/Glukosehom{\"o}ostase in vivo ist jedoch unklar. Um zu untersuchen, ob die endogenen Herzhormone die sekretorische Funktion und/oder die Proliferation von β-Zellen unter (patho)physiologischen Bedingungen in vivo modulieren, haben wir ein neues genetisches Mausmodell mit selektiver Deletion des GC-A-Rezeptors in β-Zellen (ß GC-A KO) generiert. In kultivierten Inseln von β GC-A KO-M{\"a}usen waren die insulinotropen und proliferativen Effekte von ANP aufgehoben. {\"U}bereinstimmend damit f{\"u}hrte die Infusion von BNP bei Kontroll-Tieren in vivo zu leicht erh{\"o}hten basalen Plasma-Insulinspiegeln und verbesserter Glukose-induzierter Insulinsekretion. Dieser Effekt von exogenem BNP konnte bei β GC-A KO-M{\"a}usen nicht beobachtet werden, was die effiziente Deletion des GC-A-Rezeptors in β-Zellen best{\"a}tigt. Interessanterweise hatte die Ablation des GC-A-Rezeptors auf ß-Zellen unter basalen Bedingungen keinen Einfluss auf physiologische und metabolische Parameter in vivo. Sowohl m{\"a}nnliche als auch weibliche ß GC-A KO-Tiere zeigten keine Unterschiede in der basalen Insulin- und Glukosehom{\"o}ostase, da sie {\"a}hnliche N{\"u}chtern-Blutzucker- und Insulinspiegel (nach Fasten {\"u}ber Nacht) aufwiesen wie die Kontroll-M{\"a}use. Allerdings zeigten die mit HFD gef{\"u}tterten β GC-A KO-Tiere fr{\"u}hzeitiger Glukose-Intoleranz sowie eine verminderte adaptive β-Zellproliferation. Abgesehen davon war das konsistenteste Ergebnis der in vivo-Studien der geschlechtsabh{\"a}ngige Unterschied in der Auswirkung der ß-Zellspezifischen GC-A-Deletion auf die Glukose-stimulierte Insulinsekretion. Weibliche, aber nicht m{\"a}nnliche ß GC-A KO-M{\"a}use zeigten erh{\"o}hte N{\"u}chtern-Insulinspiegel und eine signifikant erh{\"o}hte Glukose-stimulierte Insulinsekretion, was zu einer deutlich verbesserten Glukosetoleranz f{\"u}hrte. Der postulierte und untersuchte Mechanismus beinhaltet eine Interaktion von {\"O}strogenen und NPs, welche die Expression des mitochondrialen Uncoupling Protein 2 beeinflussen. Diese Arbeit erweitert das derzeitige Wissen {\"u}ber die metabolischen Effekte des NP/GC-A-Systems. Insbesondere zeigen die Ergebnisse, dass Natriuretische Peptide zu einer gesteigerten ß-Zellfunktion und Vitalit{\"a}t in fr{\"u}hen Stadien eines erh{\"o}hten Insulinbedarfs, d.h. bei Diabetes Typ 2, beitragen. Da die Studien eine wesentliche Rolle dieser kardialen Hormone im endokrinen Pankreas aufdecken, ist es umso wichtiger die pleiotropen Eigenschaften von NPs und ihre m{\"o}glichen therapeutischen Anwendungen bei kardio-metabolischen Erkrankungen weiter zu untersuchen.},
  subject      = {Guanylylzyklase},
  language  = {de}
}
@phdthesis{GuerreroGonzalez2020,
  author    = {Guerrero Gonz{\´a}lez, Hans},
  title     = {Quantifizierung von pr{\"a}- und postsynaptischen Protein-Ver{\"a}nderungen in der Amygdala-Region in SPRED2-defizienten M{\"a}usen},
  doi       = {10.25972/OPUS-21670},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-216701},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {SPRED2 ist ein Membran-assoziiertes Protein, das als wichtiger Regulator der Zelle fungiert. Es {\"u}bt eine inhibitorische Wirkung auf dem Ras/ERK/MAPK-Signalweg und ist u.a. in der Neurogenese im zentralen Nervensystem beteiligt. Durch diverse Verhaltenstests in SPRED2-KO M{\"a}usen konnten OCD-{\"a}hnliche Symptome bei den Tieren festgestellt werden sowie eine vermehrte Aktivit{\"a}t in thalamo-amygdalen Synapsen. Zur weiteren Abkl{\"a}rung dieser synaptischen Dysfunktion, wurde eine Quantifizierung von pr{\"a}- und postsynaptischen Protein-Ver{\"a}nderungen in der Amygdala-Region in SPRED2-defizienten M{\"a}usen im Vergleich zur Wildtyp M{\"a}usen durchgef{\"u}hrt. Hier konnten signifikante Unterschiede festgestellt werden.},
  subject      = {Spred-Proteine},
  language  = {de}
}
@article{TianYangGao2020,
  author    = {Tian, Yuehui and Yang, Shang and Gao, Shiqiang},
  title     = {Advances, perspectives and potential engineering strategies of light-gated phosphodiesterases for optogenetic applications},
  series = {International Journal of Molecular Sciences},
  volume    = {21},
  journal   = {International Journal of Molecular Sciences},
  number    = {20},
  issn      = {1422-0067},
  doi       = {10.3390/ijms21207544},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236203},
  year      = {2020},
  abstract  = {The second messengers, cyclic adenosine 3′-5′-monophosphate (cAMP) and cyclic guanosine 3′-5′-monophosphate (cGMP), play important roles in many animal cells by regulating intracellular signaling pathways and modulating cell physiology. Environmental cues like temperature, light, and chemical compounds can stimulate cell surface receptors and trigger the generation of second messengers and the following regulations. The spread of cAMP and cGMP is further shaped by cyclic nucleotide phosphodiesterases (PDEs) for orchestration of intracellular microdomain signaling. However, localized intracellular cAMP and cGMP signaling requires further investigation. Optogenetic manipulation of cAMP and cGMP offers new opportunities for spatio-temporally precise study of their signaling mechanism. Light-gated nucleotide cyclases are well developed and applied for cAMP/cGMP manipulation. Recently discovered rhodopsin phosphodiesterase genes from protists established a new and direct biological connection between light and PDEs. Light-regulated PDEs are under development, and of demand to complete the toolkit for cAMP/cGMP manipulation. In this review, we summarize the state of the art, pros and cons of artificial and natural light-regulated PDEs, and discuss potential new strategies of developing light-gated PDEs for optogenetic manipulation.},
  language  = {en}
}
@article{JessenKressBaluapurietal.2020,
  author    = {Jessen, Christina and Kreß, Julia K. C. and Baluapuri, Apoorva and Hufnagel, Anita and Schmitz, Werner and Kneitz, Susanne and Roth, Sabine and Marquardt, Andr{\´e} and Appenzeller, Silke and Ade, Casten P. and Glutsch, Valerie and Wobser, Marion and Friedmann-Angeli, Jos{\´e} Pedro and Mosteo, Laura and Goding, Colin R. and Schilling, Bastian and Geissinger, Eva and Wolf, Elmar and Meierjohann, Svenja},
  title     = {The transcription factor NRF2 enhances melanoma malignancy by blocking differentiation and inducing COX2 expression},
  series = {Oncogene},
  volume    = {39},
  journal   = {Oncogene},
  issn      = {0950-9232},
  doi       = {10.1038/s41388-020-01477-8},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-235064},
  pages     = {6841-6855},
  year      = {2020},
  abstract  = {The transcription factor NRF2 is the major mediator of oxidative stress responses and is closely connected to therapy resistance in tumors harboring activating mutations in the NRF2 pathway. In melanoma, such mutations are rare, and it is unclear to what extent melanomas rely on NRF2. Here we show that NRF2 suppresses the activity of the melanocyte lineage marker MITF in melanoma, thereby reducing the expression of pigmentation markers. Intriguingly, we furthermore identified NRF2 as key regulator of immune-modulating genes, linking oxidative stress with the induction of cyclooxygenase 2 (COX2) in an ATF4-dependent manner. COX2 is critical for the secretion of prostaglandin E2 and was strongly induced by H\(_2\)O\(_2\) or TNFα only in presence of NRF2. Induction of MITF and depletion of COX2 and PGE2 were also observed in NRF2-deleted melanoma cells in vivo. Furthermore, genes corresponding to the innate immune response such as RSAD2 and IFIH1 were strongly elevated in absence of NRF2 and coincided with immune evasion parameters in human melanoma datasets. Even in vitro, NRF2 activation or prostaglandin E2 supplementation blunted the induction of the innate immune response in melanoma cells. Transcriptome analyses from lung adenocarcinomas indicate that the observed link between NRF2 and the innate immune response is not restricted to melanoma.},
  language  = {en}
}
@phdthesis{Pickel2020,
  author    = {Pickel, Simone},
  title     = {Role of the β subunit of L-type calcium channels in cardiac hypertrophy},
  doi       = {10.25972/OPUS-19282},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-192829},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {L-type calcium channels (LTCCs) control crucial physiological processes in cardiomyocytes such as the duration and amplitude of action potentials, excitation-contraction coupling and gene expression, by regulating the entry of Ca2+ into the cells. Cardiac LTCCs consist of one pore-forming α1 subunit and the accessory subunits Cavβ, Cavα2δ and Cavγ. Of these auxiliary subunits, Cavβ is the most important regulator of the channel activity; however, it can also have LTCC-independent cellular regulatory functions. Therefore, changes in the expression of Cavβ can lead not only to a dysregulation of LTCC activity, but also to changes in other cellular functions. Cardiac hypertrophy is one of the most relevant risk factors for congestive heart failure and depends on the activation of calcium-dependent prohypertrophic signaling pathways. However, the role of LTCCs and especially Cavβ in this pathology is controversial and needs to be further elucidated. Of the four Cavβ isoforms, Cavβ2 is the predominant one in cardiomyocytes. Moreover, there are five different splice variants of Cavβ2 (Cavβ2a-e), differing only in the N-terminal region. We reported that Cavβ2b is the predominant variant expressed in the heart. We also revealed that a pool of Cavβ2 is targeted to the nucleus in cardiomyocytes. The expression of the nuclear Cavβ2 decreases during in vitro and in vivo induction of cardiomyocyte hypertrophy and overexpression of a nucleus-targeted Cavβ2 completely abolishes the in vitro induced hypertrophy. Additionally, we demonstrated by shRNA-mediated protein knockdown that downregulation of Cavβ2 enhances the hypertrophy induced by the α1-adrenergic agonist phenylephrine (PE) without involvement of LTCC activity. These results suggest that Cavβ2 can regulate cardiac hypertrophy through LTCC-independent pathways. To further validate the role of the nuclear Cavβ2, we performed quantitative proteome analyses of Cavβ2-deficient neonatal rat cardiomyocytes (NRCs). The results show that downregulation of Cavβ2 influences the expression of various proteins, including a decrease of calpastatin, an inhibitor of the calcium-dependent cysteine protease calpain. Moreover, downregulation of Cavβ2 during cardiomyocyte hypertrophy drastically increases calpain activity as compared to controls after treatment with PE. Finally, the inhibition of calpain by calpeptin abolishes the increase in PE-induced hypertrophy in Cavβ2-deficient cells. These results suggest that nuclear Cavβ2 has Ca2+- and LTCC-independent functions during the development of hypertrophy. Overall, our results indicate a new role for Cavβ2 in antihypertrophic signaling in cardiac hypertrophy.},
  subject      = {Herzhypertrophie},
  language  = {en}
}
@article{CapetianMuellerVolkmannetal.2020,
  author    = {Capetian, Philipp and M{\"u}ller, Lorenz and Volkmann, Jens and Heckmann, Manfred and Erg{\"u}n, S{\"u}leyman and Wagner, Nicole},
  title     = {Visualizing the synaptic and cellular ultrastructure in neurons differentiated from human induced neural stem cells - an optimized protocol},
  series = {International Journal of Molecular Sciences},
  volume    = {21},
  journal   = {International Journal of Molecular Sciences},
  number    = {5},
  issn      = {1422-0067},
  doi       = {10.3390/ijms21051708},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236053},
  year      = {2020},
  abstract  = {The size of the synaptic subcomponents falls below the limits of visible light microscopy. Despite new developments in advanced microscopy techniques, the resolution of transmission electron microscopy (TEM) remains unsurpassed. The requirements of tissue preservation are very high, and human post mortem material often does not offer adequate quality. However, new reprogramming techniques that generate human neurons in vitro provide samples that can easily fulfill these requirements. The objective of this study was to identify the culture technique with the best ultrastructural preservation in combination with the best embedding and contrasting technique for visualizing neuronal elements. Two induced neural stem cell lines derived from healthy control subjects underwent differentiation either adherent on glass coverslips, embedded in a droplet of highly concentrated Matrigel, or as a compact neurosphere. Afterward, they were fixed using a combination of glutaraldehyde (GA) and paraformaldehyde (PFA) followed by three approaches (standard stain, Ruthenium red stain, high contrast en-bloc stain) using different combinations of membrane enhancing and contrasting steps before ultrathin sectioning and imaging by TEM. The compact free-floating neurospheres exhibited the best ultrastructural preservation. High-contrast en-bloc stain offered particularly sharp staining of membrane structures and the highest quality visualization of neuronal structures. In conclusion, compact neurospheres growing under free-floating conditions in combination with a high contrast en-bloc staining protocol, offer the optimal preservation and contrast with a particular focus on visualizing membrane structures as required for analyzing synaptic structures.},
  language  = {en}
}