Tomasz Zemojtel

Dr. Tomasz Zemojtel

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Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 July 2021 in Journal of Clinical Investigation
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Journal Article
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ASArne Sattler
Arne Sattler
ESEva Vanessa Schrezenmeier
Eva Vanessa Schrezenmeier
UWUlrike A. Weber
Ulrike A. Weber
APAlexander Potekhin
Alexander Potekhin
FBFriederike Bachmann
Friederike Bachmann
KKKatja Kotsch
Katja Kotsch
Novel mRNA-based vaccines have been proven to be powerful tools in combating the global pandemic caused by SARS-CoV-2, with BNT162b2 (trade name: Comirnaty) efficiently protecting individuals from COVID-19 across a broad age range. Still, it remains largely unknown how renal insufficiency and immunosuppressive medication affect development of vaccine-induced immunity. We therefore comprehensively analyzed humoral and cellular responses in kidney transplant recipients after the standard second vaccination dose. As opposed to all healthy vaccinees and the majority of hemodialysis patients, only 4 of 39 and 1 of 39 transplanted individuals showed IgA and IgG seroconversion at day 8 ± 1 after booster immunization, with minor changes until day 23 ± 5, respectively. Although most transplanted patients mounted spike-specific T helper cell responses, frequencies were significantly reduced compared with those in controls and dialysis patients and this was accompanied by a broad impairment in effector cytokine production, memory differentiation, and activation-related signatures. Spike-specific CD8+ T cell responses were less abundant than their CD4+ counterparts in healthy controls and hemodialysis patients and almost undetectable in transplant patients. Promotion of anti-HLA antibodies or acute rejection was not detected after vaccination. In summary, our data strongly suggest revised vaccination approaches in immunosuppressed patients, including individual immune monitoring for protection of this vulnerable group at risk of developing severe COVID-19.

18 October 2016 in Nucleic Acids Research
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Journal Article
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TPTobias Penzkofer
Tobias Penzkofer
MJMarten Jäger
Marten Jäger
MFMarek Figlerowicz
Marek Figlerowicz
RBRichard Badge
Richard Badge
SMStefan Mundlos
Stefan Mundlos
TZTomasz Zemojtel
Tomasz Zemojtel
LINE-1 (L1) insertions comprise as much as 17% of the human genome sequence, and similar proportions have been recorded for other mammalian species. Given the established role of L1 retrotransposons in shaping mammalian genomes, it becomes an important task to track and annotate the sources of this activity: full length elements, able to encode the cis and trans acting components of the retrotransposition machinery. The L1Base database (http://l1base.charite.de) contains annotated full-length sequences of LINE-1 transposons including putatively active L1s. For the new version of L1Base, a LINE-1 annotation tool, L1Xplorer, has been used to mine potentially active L1 retrotransposons from the reference genome sequences of 17 mammals. The current release of the human genome, GRCh38, contains 146 putatively active L1 elements or full length intact L1 elements (FLIs). The newest versions of the mouse, GRCm38 and the rat, Rnor_6.0, genomes contain 2811 and 492 FLIs, respectively. Most likely reflecting the current level of completeness of the genome project, the latest reference sequence of the common chimpanzee genome, PT 2.19, only contains 19 FLIs. Of note, the current assemblies of the dog, CF 3.1 and the sheep, OA 3.1, genomes contain 264 and 598 FLIs, respectively. Further developments in the new version of L1Base include an updated website with implementation of modern web server technologies. including a more responsive design for an improved user experience, as well as the addition of data sharing capabilities for L1Xplorer annotation.

25 December 2014 in Human Mutation
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Tatehiro KagawaTatehiro Kagawa
Tatehiro Kagawa
AOAkira Oka
Akira Oka
YKYoshinao Kobayashi
Yoshinao Kobayashi
YHYoichi Hiasa
Yoichi Hiasa
TKTsuneo Kitamura
Tsuneo Kitamura
TMTetsuya Mine
Tetsuya Mine
Sequences of long‐interspersed elements (LINE‐1, L1) make up ∼17% of the human genome. De novo insertions of retrotransposition‐active L1s can result in genetic diseases. It has been recently shown that the homozygous inactivation of two adjacent genes SLCO1B1 and SLCO1B3 encoding organic anion transporting polypeptides OATP1B1 and OATP1B3 causes a benign recessive disease presenting with conjugated hyperbilirubinemia, Rotor syndrome. Here, we examined SLCO1B1 and SLCO1B3 genes in six Japanese diagnosed with Rotor syndrome on the basis of laboratory data and laparoscopy. All six Japanese patients were homozygous for the c.1738C>T nonsense mutation in SLCO1B1 and homozygous for the insertion of a ∼6.1‐kbp L1 retrotransposon in intron 5 of SLCO1B3, which altogether make up a Japanese‐specific haplotype. RNA analysis revealed that the L1 insertion induced deleterious splicing resulting in SLCO1B3 transcripts lacking exon 5 or exons 5–7 and containing premature stop codons. The expression of OATP1B1 and OATP1B3 proteins was not detected in liver tissues. This is the first documented case of a population‐specific polymorphic intronic L1 transposon insertion contributing to molecular etiology of recessive genetic disease. Since L1 activity in human genomes is currently seen as a major source of individual genetic variation, further investigations are warranted to determine whether this phenomenon results in other autosomal‐recessive diseases.

21 January 2019 in Cancers
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Journal Article
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PCPetros Christopoulos
Petros Christopoulos
SDSteffen Dietz
Steffen Dietz
MKMartina Kirchner
Martina Kirchner
AVAnna-Lena Volckmar
Anna-Lena Volckmar
VEVolker Endris
Volker Endris
Albrecht  StenzingerAlbrecht Stenzinger
Albrecht Stenzinger
Anaplastic lymphoma kinase (ALK) sequencing can identify resistance mechanisms and guide next-line therapy in ALK+ non-small-cell lung cancer (NSCLC), but the clinical significance of other rebiopsy findings remains unclear. We analysed all stage-IV ALK+ NSCLC patients with longitudinally assessable TP53 status treated in our institutions (n = 62). Patients with TP53 mutations at baseline (TP53mutbas, n = 23) had worse overall survival (OS) than patients with initially wild-type tumours (TP53wtbas, n = 39, 44 vs. 62 months in median, p = 0.018). Within the generally favourable TP53wtbas group, detection of TP53 mutations at progression defined a “converted” subgroup (TP53mutconv, n = 9) with inferior OS, similar to that of TP53mutbas and shorter than that of patients remaining TP53 wild-type (TP53wtprogr, 45 vs. 94 months, p = 0.043). Progression-free survival (PFS) under treatment with tyrosine kinase inhibitors (TKI) for TP53mutconv was comparable to that of TP53mutbas and also shorter than that of TP53wtprogr cases (5 and 8 vs. 13 months, p = 0.0039). Fewer TP53wtprogr than TP53mutbas or TP53mutconv cases presented with metastatic disease at diagnosis (67% vs. 91% or 100%, p < 0.05). Thus, acquisition of TP53 mutations at progression is associated with more aggressive disease, shorter TKI responses and inferior OS in ALK+ NSCLC, comparable to primary TP53 mutated cases.

26 April 2020 in Molecular Genetics & Genomic Medicine
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AJAleksandra Jezela-Stanek
Aleksandra Jezela-Stanek
ECElżbieta Ciara
Elżbieta Ciara
DJDorota Jurkiewicz
Dorota Jurkiewicz
MKMarzena Kucharczyk
Marzena Kucharczyk
MJMaria Jędrzejowska
Maria Jędrzejowska
TZTomasz Zemojtel
Tomasz Zemojtel
Background: Due to extensive clinical and genetic heterogeneity of intellectual disability (ID) syndromes, the process of diagnosis is very challenging even for expert clinicians. Despite recent advancements in molecular diagnostics methodologies, a significant fraction of ID patients remains without a clinical diagnosis.Methods, results, and conclusions: Here, in a prospective study on a cohort of 21 families (trios) with a child presenting with ID of unknown etiology, we executed phenotype‐driven bioinformatic analysis method, PhenIX, utilizing targeted next‐generation sequencing (NGS) data and Human Phenotype Ontology (HPO)‐encoded phenotype data. This approach resulted in clinical diagnosis for eight individuals presenting with atypical manifestations of Rubinstein–Taybi syndrome 2 (MIM 613684), Spastic Paraplegia 50 (MIM 612936), Wiedemann–Steiner syndrome (MIM 605130), Cornelia de Lange syndrome 2 (MIM 300590), Cerebral creatine deficiency syndrome 1 (MIM 300352), Glass Syndrome (MIM 612313), Mental retardation, autosomal dominant 31 (MIM 616158), and Bosch–Boonstra–Schaaf optic atrophy syndrome (MIM 615722).

23 June 2021 in Genes
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Journal Article
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MBMagdalena Badura-Stronka
Magdalena Badura-Stronka
AWAnna Winczewska-Wiktor
Anna Winczewska-Wiktor
APAnna Pietrzak
Anna Pietrzak
AHAdam Sebastian Hirschfeld
Adam Sebastian Hirschfeld
TZTomasz Zemojtel
Tomasz Zemojtel
BSBarbara Steinborn
Barbara Steinborn
CLN8 is a ubiquitously expressed membrane-spanning protein that localizes primarily in the ER, with partial localization in the ER-Golgi intermediate compartment. Mutations in CLN8 cause late-infantile neuronal ceroid lipofuscinosis (LINCL). We describe a female pediatric patient with LINCL. She exhibited a typical phenotype associated with LINCL, except she did not present spontaneous myoclonus, her symptoms occurrence was slower and developed focal sensory visual seizures. In addition, whole-exome sequencing identified a novel homozygous variant in CLN8, c.531G>T, resulting in p.Trp177Cys. Ultrastructural examination featured abundant lipofuscin deposits within mucosal cells, macrophages, and monocytes. We report a novel CLN8 mutation as a cause for NCL8 in a girl with developmental delay and epilepsy, cerebellar syndrome, visual loss, and progressive cognitive and motor regression. This case, together with an analysis of the available literature, emphasizes the existence of a continuous spectrum of CLN8-associated phenotypes rather than a sharp distinction between them.