@phdthesis{Friedrich2019, author = {Friedrich, Maximilian Uwe}, title = {Funktionelle Charakterisierung einer Tripletdeletion in SLC5A4 (SGLT3) als Kandidatengen f{\"u}r das Aufmerksamkeitsdefizit-/ Hyperaktivit{\"a}tssyndrom (ADHS)}, doi = {10.25972/OPUS-18479}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184791}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Natrium-Glukose Transporter (SGLT) geh{\"o}ren zur „solute carrier 5" (SLC5) Familie, die sich durch einen sekund{\"a}r aktiven, natriumabh{\"a}ngigen Transport von Zuckern und an-deren Molek{\"u}len nach intrazellul{\"a}r auszeichnen. Die durch das Gen SLC5A4 kodierte Isoform SGLT3 transportiert dagegen keinen Zucker, sondern verh{\"a}lt sich als Glukosesensor, der nach Bindung seiner Liganden eine Membrandepolarisation induziert. In genomweiten Exomsequenzierungsstudien (whole exome sequencing, WES) mehrerer erweiterter Stammb{\"a}ume mit hoher Pr{\"a}valenz des Aufmerksamkeitsdefizit-/Hyperaktivit{\"a}tssyndroms (ADHS) wurde im Vorfeld eine ATG-Tripletdeletion in SLC5A4 identifiziert, die zum Verlust einer Aminos{\"a}ure (ΔM500) in SGLT3 f{\"u}hrt und zumindest partiell mit dem klinischen Ph{\"a}notyp kosegregiert. In der vorliegenden Arbeit wurde die zentralnerv{\"o}se Expression von SGLT3 auf RNA- Ebene mittels Reverse-Transkriptase PCR sowie real-time PCR aus humanen Gesamt-RNAs nachgewiesen. Dabei konnte eine ubiquit{\"a}re Expression im Gehirn mit relativ erh{\"o}hter Expression unter anderem in Striatum und Hypothalamus, deren Dysfunktion in der Pathogenese des ADHS impliziert wurde, gezeigt werden. Da Mutationen in homologen Dom{\"a}nen der eng strukturverwandten Isoformen SGLT1 und SGLT2 sowohl intestinale als auch renale Funktionen schwer beeintr{\"a}chtigen, wurden in dieser Arbeit funktionelle Charakteristika sowohl des wildtypischen als auch der ΔM500 und der benachbarten ΔI501 Deletionsvariante von SGLT3 mittels Zwei-Elektroden Spannungs- und Stromklemme in entsprechend cRNA-injizierten Xenopus laevis Oozyten untersucht. Der hochpotente SGLT3-spezifische Iminozuckeragonist 1-Desoxynojirimycin (DNJ) induzierte an SGLT3-exprimierenden Oozyten in sauren Bedingungen etwa dreifach gr{\"o}ßere Kationeneinstr{\"o}me als D-Glukose, was sowohl im Spannungsklemmen-, und anhand einer entsprechenden Membrandepolarisation im Stromklemmenmodus gezeigt wurde. Die mit der ΔM500 bzw. ΔI501 Variante injizierten Oozyten dagegen zeigten in den maximalen Aktivierungsbedingungen um 92\% bzw. 96\% (p<0,01) reduzierte Kationeneinstr{\"o}me, sodass diese als hochgradig sch{\"a}dliche „Loss of Function" Mutationen in SGLT3 charakterisiert wurden. Dieser Befund wurde mittels bioinformatischer in-silico Effektvorhersage validiert. Um Konsequenzen der Sequenzalteration auf den Membraneinbau der Transporter zu untersuchen, wurden die mit einem gelb fluoreszierenden Farbstoff (YFP) markierten Transporter in Oozytenmembranen mittels Laser-Scanning Mikroskop nachgewiesen und die jeweiligen Mengen der Konstrukte anhand der Fluoreszenzintensit{\"a}ten quantifiziert. Dabei zeigte sich eine um 53\% bzw. 42\% (p<0,01) reduzierte Menge der mutierten Konstrukte ΔM500 bzw. ΔI501 in der Membran, was zus{\"a}tzliche sch{\"a}dliche Effekte der Mutationen auf das sogenannte Membrantargeting der Transporter belegt. Zusammenfassend demonstrieren die Ergebnisse dieser Arbeit, dass die ΔM500 Variante von SGLT3, welcher in ADHS-relevanten Hirnarealen exprimiert wird, dessen sub-stratinduzierte Natriumleitf{\"a}higkeit aufhebt und den Membraneinbau beeintr{\"a}chtigen k{\"o}nnte, was in Wechselwirkung mit anderen genetischen ADHS Risikovarianten das Risiko f{\"u}r ADHS in Mutationstr{\"a}gern beeinflussen kann.}, subject = {ADHS}, language = {de} } @article{ArnholdtKamawalHolzapfeletal.2018, author = {Arnholdt, J{\"o}rg and Kamawal, Yama and Holzapfel, Boris Michael and Ripp, Axel and Rudert, Maximilian and Steinert, Andre Friedrich}, title = {Evaluation of implant fit and frontal plane alignment after bi-compartmental knee arthroplasty using patient-specific instruments and implants}, series = {Archives of Medical Science}, volume = {14}, journal = {Archives of Medical Science}, number = {6}, doi = {10.5114/aoms.2018.79007}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159668}, pages = {1424-1431}, year = {2018}, abstract = {Introduction The goals of successful bi-compartmental knee arthroplasty are to achieve correct fit and positioning of the implant, while appropriately correcting the mechanical alignment of the leg after surgery. As these requirements are not always reliably fulfilled using off-the-shelf implant systems, newer approaches for bi-compartmental resurfacing have been explored. Material and methods In this article we report the radiographic results of 30 patients with anteromedial osteoarthritis (OA) who were treated with a novel patient-specific fixed-bearing bi-compartmental knee resurfacing system using custom-made implants and instruments. Utilizing standardized pre- and postoperative radiographic analyses (based on anterior-posterior and lateral, anterior-posterior weight-bearing full-length radiographs, patella skyline views and preoperative computed tomography (CT) scanning) implant fit and positioning as well as correction of the mechanical axis (hip-knee-ankle angle, HKA) were determined. Results On average, HKA was corrected from 173.4 ±3.47° preoperatively to 179.4 ±2.85° postoperatively. The coronal femoro-tibial angle was corrected on average 5.61°. The preoperative tibial slope measured on lateral views was 6.38 ±2.4°, while the average slope in the CT-based planning protocol (iView) was 6.14 ±2.40°. Postoperative lateral tibial slope was determined to be 5.77 ±1.97°. The thickness of the posterior femoral cuts was measured intraoperatively and, in all cases, corresponded well to the targeted thickness of the cuts provided by the iView. The joint line was preserved in all cases and the average Insall-Salvati index was 1.078 ±0.11 pre- and 1.072 ±0.11 postoperatively. The fit of the implant components measured by over- or underhang was excellent throughout (< 1.01 mm). Conclusions Custom-made bicompartmental knee arthroplasty can ensure optimized fitting and positioning of the implant with restoration of the leg axis. These implants could be considered as an alternative primary solution for knee surgeons treating bi-compartmental disease.}, language = {en} } @article{FriedrichEldebakeyRoothansetal.2022, author = {Friedrich, Maximilian U. and Eldebakey, Hazem and Roothans, Jonas and Capetian, Philipp and Zwergal, Andreas and Volkmann, Jens and Reich, Martin}, title = {Current-dependent ocular tilt reaction in deep brain stimulation of the subthalamic nucleus: Evidence for an incerto-interstitial pathway?}, series = {European Journal of Neurology}, volume = {29}, journal = {European Journal of Neurology}, number = {5}, doi = {10.1111/ene.15257}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-318700}, pages = {1545 -- 1549}, year = {2022}, abstract = {Background and purpose The aim was to characterize a combined vestibular, ocular motor and postural syndrome induced by deep brain stimulation (DBS) of the subthalamic nucleus in a patient with Parkinson's disease. Methods In a systematic DBS programming session, eye, head and trunk position in roll and pitch plane were documented as a function of stimulation amplitude and field direction. Repeat ocular coherence tomography was used to estimate ocular torsion. The interstitial nucleus of Cajal (INC), zona incerta (ZI) and ascending vestibular fibre tracts were segmented on magnetic resonance imaging using both individual and normative structural connectomic data. Thresholded symptom-associated volumes of tissue activated (VTA) were calculated based on documented stimulation parameters. Results Ipsilateral ocular tilt reaction and body lateropulsion as well as contralateral torsional nystagmus were elicited by the right electrode in a current-dependent manner and subsided after DBS deactivation. With increasing currents, binocular tonic upgaze and body retropulsion were observed. Symptoms were consistent with an irritative effect on the INC. Symptom-associated VTA was found to overlap with the dorsal ZI and the ipsilateral vestibulothalamic tract, while lying rather distant to the INC proper. A ZI-to-INC 'incerto-interstitial' tract with contact to the medial-uppermost portion of the VTA could be traced. Conclusion Unilateral stimulation of INC-related circuitry induces an ipsilateral vestibular, ocular motor and postural roll-plane syndrome, which converts into a pitch-plane syndrome when functional activation expands bilaterally. In this case, tractography points to an incerto-interstitial pathway, a tract previously only characterized in non-human primates. Directional current steering proved useful in managing this rare side effect.}, language = {en} } @article{MerzDietzVonhausenetal.2020, author = {Merz, Julia and Dietz, Maximilian and Vonhausen, Yvonne and W{\"o}ber, Frederik and Friedrich, Alexandra and Sieh, Daniel and Krummenacher, Ivo and Braunschweig, Holger and Moos, Michael and Holzapfel, Marco and Lambert, Christoph and Marder, Todd B.}, title = {Synthesis, Photophysical and Electronic Properties of New Red-to-NIR Emitting Donor-Acceptor Pyrene Derivatives}, series = {Chemistry - A European Journal}, volume = {26}, journal = {Chemistry - A European Journal}, number = {2}, doi = {10.1002/chem.201904219}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-207486}, pages = {438-453}, year = {2020}, abstract = {We synthesized new pyrene derivatives with strong bis(para -methoxyphenyl)amine donors at the 2,7-positions and n -azaacene acceptors at the K-region of pyrene. The compounds possess a strong intramolecular charge transfer, leading to unusual properties such as emission in the red to NIR region (700 nm), which has not been reported before for monomeric pyrenes. Detailed photophysical studies reveal very long intrinsic lifetimes of >100 ns for the new compounds, which is typical for 2,7-substituted pyrenes but not for K-region substituted pyrenes. The incorporation of strong donors and acceptors leads to very low reduction and oxidation potentials, and spectroelectrochemical studies show that the compounds are on the borderline between localized Robin-Day class-II and delocalized Robin-Day class-III species.}, language = {en} } @article{StegnervanEeuwijkAngayetal.2017, author = {Stegner, David and van Eeuwijk, Judith M.M. and Angay, Oğuzhan and Gorelashvili, Maximilian G. and Semeniak, Daniela and Pinnecker, J{\"u}rgen and Schmithausen, Patrick and Meyer, Imke and Friedrich, Mike and D{\"u}tting, Sebastian and Brede, Christian and Beilhack, Andreas and Schulze, Harald and Nieswandt, Bernhard and Heinze, Katrin G.}, title = {Thrombopoiesis is spatially regulated by the bone marrow vasculature}, series = {Nature Communications}, volume = {8}, journal = {Nature Communications}, number = {127}, doi = {10.1038/s41467-017-00201-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170591}, year = {2017}, abstract = {In mammals, megakaryocytes (MKs) in the bone marrow (BM) produce blood platelets, required for hemostasis and thrombosis. MKs originate from hematopoietic stem cells and are thought to migrate from an endosteal niche towards the vascular sinusoids during their maturation. Through imaging of MKs in the intact BM, here we show that MKs can be found within the entire BM, without a bias towards bone-distant regions. By combining in vivo two-photon microscopy and in situ light-sheet fluorescence microscopy with computational simulations, we reveal surprisingly slow MK migration, limited intervascular space, and a vessel-biased MK pool. These data challenge the current thrombopoiesis model of MK migration and support a modified model, where MKs at sinusoids are replenished by sinusoidal precursors rather than cells from a distant periostic niche. As MKs do not need to migrate to reach the vessel, therapies to increase MK numbers might be sufficient to raise platelet counts.}, language = {en} } @article{FriedrichHartigPruessetal.2022, author = {Friedrich, Maximilian and Hartig, Johannes and Pr{\"u}ss, Harald and Ip, Wang Chi and Volkmann, Jens}, title = {Rapidly progressive dementia: Extending the spectrum of GFAP-astrocytopathies?}, series = {Annals of Clinical and Translational Neurology}, volume = {9}, journal = {Annals of Clinical and Translational Neurology}, number = {3}, doi = {10.1002/acn3.51513}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312957}, pages = {410-415}, year = {2022}, abstract = {Autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A) is a steroid-responsive meningoencephalomyelitis, sometimes presenting with atypical clinical signs such as movement disorders or psychiatric and autonomic features. Beyond clinical presentation and imaging, diagnosis relies on detection of GFAP-antibodies (AB) in CSF. Using quantitative behavioral, serologic, and immunohistochemical analyses, we characterize two patients longitudinally over 18-24 months who presented with rapidly progressive neurocognitive deterioration in the context of GFAP-AB in CSF and unremarkable cranial MRI studies. Intensified immunotherapy was associated with clinical stabilization. The value of GFAP-AB screening in selected cases of rapidly progressive dementias is discussed.}, language = {en} } @article{SchmitzRiesKodereretal.2021, author = {Schmitz, Werner and Ries, Elena and Koderer, Corinna and V{\"o}lter, Maximilian Friedrich and W{\"u}nsch, Anna Chiara and El-Mesery, Mohamed and Frackmann, Kyra and K{\"u}bler, Alexander Christian and Linz, Christian and Seher, Axel}, title = {Cysteine restriction in murine L929 fibroblasts as an alternative strategy to methionine restriction in cancer therapy}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {21}, issn = {1422-0067}, doi = {10.3390/ijms222111630}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265486}, year = {2021}, abstract = {Methionine restriction (MetR) is an efficient method of amino acid restriction (AR) in cells and organisms that induces low energy metabolism (LEM) similar to caloric restriction (CR). The implementation of MetR as a therapy for cancer or other diseases is not simple since the elimination of a single amino acid in the diet is difficult. However, the in vivo turnover rate of cysteine is usually higher than the rate of intake through food. For this reason, every cell can enzymatically synthesize cysteine from methionine, which enables the use of specific enzymatic inhibitors. In this work, we analysed the potential of cysteine restriction (CysR) in the murine cell line L929. This study determined metabolic fingerprints using mass spectrometry (LC/MS). The profiles were compared with profiles created in an earlier work under MetR. The study was supplemented by proliferation studies using D-amino acid analogues and inhibitors of intracellular cysteine synthesis. CysR showed a proliferation inhibition potential comparable to that of MetR. However, the metabolic footprints differed significantly and showed that CysR does not induce classic LEM at the metabolic level. Nevertheless, CysR offers great potential as an alternative for decisive interventions in general and tumour metabolism at the metabolic level.}, language = {en} } @article{SchaeferFriedrichJorgensenetal.2018, author = {Sch{\"a}fer, Nadine and Friedrich, Maximilian and J{\o}rgensen, Morten Egevang and Kollert, Sina and Koepsell, Hermann and Wischmeyer, Erhard and Lesch, Klaus-Peter and Geiger, Dietmar and D{\"o}ring, Frank}, title = {Functional analysis of a triplet deletion in the gene encoding the sodium glucose transporter 3, a potential risk factor for ADHD}, series = {PLoS ONE}, volume = {13}, journal = {PLoS ONE}, number = {10}, doi = {10.1371/journal.pone.0205109}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176495}, pages = {e0205109}, year = {2018}, abstract = {Sodium-glucose transporters (SGLT) belong to the solute carrier 5 family, which is characterized by sodium dependent transport of sugars and other solutes. In contrast, the human SGLT3 (hSGLT3) isoform, encoded by SLC5A4, acts as a glucose sensor that does not transport sugar but induces membrane depolarization by Na\(^{+}\) currents upon ligand binding. Whole-exome sequencing (WES) of several extended pedigrees with high density of attention-deficit/hyperactivity disorder (ADHD) identified a triplet ATG deletion in SLC5A4 leading to a single amino acid loss (ΔM500) in the hSGLT3 protein imperfectly co-segregating with the clinical phenotype of ADHD. Since mutations in homologous domains of hSGLT1 and hSGLT2 were found to affect intestinal and renal function, respectively, we analyzed the functional properties of hSGLT3[wt] and [ΔM500] by voltage clamp and current clamp recordings from cRNA-injected Xenopus laevis oocytes. The cation conductance of hSGLT3[wt] was activated by application of glucose or the specific agonist 1-desoxynojirimycin (DNJ) as revealed by inward currents in the voltage clamp configuration and cell depolarization in the current clamp mode. Almost no currents and changes in membrane potential were observed when glucose or DNJ were applied to hSGLT3[ΔM500]-injected oocytes, demonstrating a loss of function by this amino acid deletion in hSGLT3. To monitor membrane targeting of wt and mutant hSGLT3, fusion constructs with YFP were generated, heterologously expressed in Xenopus laevis oocytes and analyzed for membrane fluorescence by confocal microscopy. In comparison to hSGLT3[wt] the fluorescent signal of mutant [ΔM500] was reduced by 43\% indicating that the mutant phenotype might mainly result from inaccurate membrane targeting. As revealed by homology modeling, residue M500 is located in TM11 suggesting that in addition to the core structure (TM1-TM10) of the transporter, the surrounding TMs are equally crucial for transport/sensor function. In conclusion, our findings indicate that the deletion [ΔM500] in hSGLT3 inhibits membrane targeting and thus largely disrupts glucose-induced sodium conductance, which may, in interaction with other ADHD risk-related gene variants, influence the risk for ADHD in deletion carriers.}, language = {en} } @article{FriedrichSchneiderBuerkleinetal.2023, author = {Friedrich, Maximilian U. and Schneider, Erich and Buerklein, Miriam and Taeger, Johannes and Hartig, Johannes and Volkmann, Jens and Peach, Robert and Zeller, Daniel}, title = {Smartphone video nystagmography using convolutional neural networks: ConVNG}, series = {Journal of Neurology}, volume = {270}, journal = {Journal of Neurology}, number = {5}, doi = {10.1007/s00415-022-11493-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324526}, pages = {2518-2530}, year = {2023}, abstract = {Background Eye movement abnormalities are commonplace in neurological disorders. However, unaided eye movement assessments lack granularity. Although videooculography (VOG) improves diagnostic accuracy, resource intensiveness precludes its broad use. To bridge this care gap, we here validate a framework for smartphone video-based nystagmography capitalizing on recent computer vision advances. Methods A convolutional neural network was fine-tuned for pupil tracking using > 550 annotated frames: ConVNG. In a cross-sectional approach, slow-phase velocity of optokinetic nystagmus was calculated in 10 subjects using ConVNG and VOG. Equivalence of accuracy and precision was assessed using the "two one-sample t-test" (TOST) and Bayesian interval-null approaches. ConVNG was systematically compared to OpenFace and MediaPipe as computer vision (CV) benchmarks for gaze estimation. Results ConVNG tracking accuracy reached 9-15\% of an average pupil diameter. In a fully independent clinical video dataset, ConVNG robustly detected pupil keypoints (median prediction confidence 0.85). SPV measurement accuracy was equivalent to VOG (TOST p < 0.017; Bayes factors (BF) > 24). ConVNG, but not MediaPipe, achieved equivalence to VOG in all SPV calculations. Median precision was 0.30°/s for ConVNG, 0.7°/s for MediaPipe and 0.12°/s for VOG. ConVNG precision was significantly higher than MediaPipe in vertical planes, but both algorithms' precision was inferior to VOG. Conclusions ConVNG enables offline smartphone video nystagmography with an accuracy comparable to VOG and significantly higher precision than MediaPipe, a benchmark computer vision application for gaze estimation. This serves as a blueprint for highly accessible tools with potential to accelerate progress toward precise and personalized Medicine.}, language = {en} }