Biology subjects

Holthaus, D.

Publications and source records attributed to Holthaus, D..

7 recordsLinked to original sources

bioRxiv2026

Organoids serve as viable in vitro model for functional precision medicine for mesonephric-like adenocarcinoma of the ovary

BackgroundMesonephric-like adenocarcinoma has been recently classified as a rare type of ovarian carcinoma. Description of these tumours have been rare and mostly covered in case reports. In some cases, molecular characterization by sequencing has been employed for guided therapy recommendations, however, functional chemosensitivity testing of targetable pathways using advanced in vitro cellular models such as organoids has not been reported so far. Here, we report on a case of ovarian cancer that was later identified as mesonephric-like adenocarcinoma at an advanced stage. MethodsThe tumour was characterized by molecular techniques including immunohistochemistry and whole-exome sequencing. At the same time, ovarian cancer organoids were established by adapting existing protocols for high-grade serous ovarian carcinoma. The organoids were subsequently used for functional in vitro chemosensitivity testing by treatment with standard-of-care chemotherapeutics cisplatin, paclitaxel, and the Poly (ADP-Ribose) Polymerase 1-inhibitor olaparib. Based on molecular characteristics, we also applied the inhibitor binimetinib, to target Mitogen-Activated Protein Kinase downstream of the KRAS Proto-Oncogene. Additionally, chemotoxicity testing with healthy fallopian tube organoids and high-grade ovarian cancer organoids was applied to determine the therapeutic window. ResultsImmunohistochemical analysis showed characteristic PAX8+, GATA3+, TFF1+, ER-, PR-, WT1- staining while the sequencing revealed mutations in 31 genes of which KRAS G12V and DYNC1H1 G4072S were annotated as (likely) pathogenic. The tumour was mismatch-repair proficient. Tumour-derived organoids proved to be highly resistant to standard-of-care chemotherapeutics cisplatin, paclitaxel, and olaparib, but sensitive to inhibition by binimetinib, which aligned well with the molecular characteristics. Direct comparison to healthy fallopian tube organoids and high-grade ovarian cancer organoids confirmed low cytotoxic potential underlining a feasible therapeutic window for binimetinib. ConclusionsFor the first time, we show that existing protocols for high-grade serous ovarian carcinoma can be used for the generation of organoids derived from mesonephric-like adenocarcinoma. These organoids could be used as an essential tool for functional precision medicine purposes. This functional data could be applied as an additional layer for molecular tumour boards diagnostics by supporting molecular datasets and even identify targetable pathways beyond genetic variations, thus offering novel therapeutic options particularly for rare and aggressive tumours.

cancer biology↗

bioRxiv2025

Infection and herbicide exposure implicate c-Abl kinase in α-Synuclein Ser129 phosphorylation

BackgroundParkinsons disease is a complex multifactorial neurodegenerative disorder characterized by -Synuclein aggregation in Lewy bodies, with phosphorylation at serine 129 (pSer129) being a critical pathological hallmark. However, the exact mechanisms by which environmental triggers lead to this disease phenotype remain poorly understood. In this study we compare the effects of an exemplary infection and a certain pesticide exposure on the generation of pSer129 -Synuclein, with a focus on the involvement of cellular kinases in this process. MethodsTwo distinct environmental stressors were applied to neuronal cells: the pesticide rotenone and the well-studied gastric bacterium Helicobacter pylori (H. pylori). Phosphorylation of Ser129 -Synuclein was assessed by immunofluorescent staining and Western blotting. Cells were treated with mechanistically distinct c-Abl inhibitors, and pSer129 -Synuclein was detected using Western blotting and activities of the upstream serine-threonine kinase were predicted by kinase profiling and Western blotting, analyzed by one-way ANOVA followed by Tukeys multiple comparisons test. Moreover, transcriptome analyses of treated cells were performed and ingenuity pathway analysis and Deseq2 were applied to unravel the affected neurodegenerative pathways. ResultsThe functional analysis of our RNA sequence data demonstrated that both H. pylori and rotenone induced oxidative stress and neuroinflammation by stimulating neurodegenerative pathways. Rotenone and H. pylori activated c-Abl, likely through the induced oxidative stress and promoted -Synuclein phosphorylation. The kinase inhibitors Ponatinib and Asciminib effectively prevented pSer129 -Synuclein accumulation and reversed associated gene expression changes induced by rotenone or H. pylori. Moreover, GSK3{beta} appeared to be involved in the induction of Ser129 phosphorylation via activated c-Abl. Furthermore, H. pyloris vacuolating cytotoxin appeared to play a crucial role in the phosphorylation of pSer129 -Synuclein by c-Abl. ConclusionsThese findings highlight the pivotal role of c-Abl in -Synucleopathies and provide insights into shared mechanisms between infection and pesticide exposure, offering potential therapeutic targets for Parkinsons disease and related pathologies involving -Synuclein modification.

neuroscience↗

bioRxiv2024

Inhibition of ADAM17 increases cytotoxic effect of cisplatin in cervical spheroids and organoids

BackgroundCervical cancer represents one of the main causes of female, cancer-related mortality worldwide. The majority of cancers are caused by human papillomaviruses such as HPV16 and HPV18. As chemotherapeutic resistance to first-line platinum treatment is still a predominant clinical challenge in advanced cervical cancer, novel treatment options including combinatorial therapies are urgently required to overcome chemotherapeutic resistance. Inhibition of A Disintegrin And Metalloproteinase (ADAM)-family members, heavily involved in tumour progression of a vast range of solid tumours, strongly improved response to chemotherapeutic treatment in other tumour entities including ovarian cancer. MethodsWe established two- and three-dimensional models derived from three traditional cervical cancer cell lines and ectocervical cancer-derived organoids. Following characterisation, these models were used to investigate their response to cisplatin treatment in the absence and presence of ADAM inhibitors using viability assays and automated live cell imaging. ResultsThe pivotal role of the metalloprotease ADAM17 driving chemotherapy resistance was detectable in all ectocervical cultures irrespective of the model system used, whereas ADAM10 inhibition was predominantly effective only in loosely aggregated spheroids. We showed prominent differences regarding treatment responses between 2D monolayers compared to 3D spheroid and 3D organoid model systems. Particularly, the organoid system, regarded as the closest representation of primary tumours, exhibited reliably the combinatorial effect of ADAM17 inhibition and cisplatin in all three individual donors. ConclusionsAs two- and three-dimensional models of the same cell lines differ in their responses to chemotherapy it is essential to validate treatment strategies in more advanced model systems representing the patient situation more realistically. Ectocervical organoids showed reliable results regarding treatment responses closely mimicking the primary tumours and could therefore serve as an important tool for personalized medicine in cervical cancer. These findings strengthen the role of ADAM17 as a potential novel target for combinatorial treatments to overcome chemoresistance in cervical cancer.

cancer biology↗

bioRxiv2023

γδ T cell-mediated cytotoxicity against patient-derived healthy and cancer cervical organoids

Cervical cancer is a leading cause of death among women globally, primarily driven by high-risk papillomaviruses. However, the effectiveness of chemotherapy is limited, underscoring the potential of personalized immunotherapies. Patient-derived organoids, which possess cellular heterogeneity, proper epithelial architecture and functionality, and long-term propagation capabilities offer a promising platform for developing viable strategies. In addition to {beta} T cells and natural killer (NK) cells, {gamma}{delta} T cells represent a cell population with significant therapeutic potential against both hematologic and solid tumours. To evaluate the efficacy of {gamma}{delta} T cells in cervical cancer treatment, we generated patient-derived healthy and cancer ectocervical organoids. Furthermore, we examined transformed healthy organoids, expressing HPV16 oncogenes E6 and E7. We analysed the effector function of in vitro expanded {gamma}{delta} T cells upon co-culture with organoids. Our findings demonstrated that healthy cervical organoids were less susceptible to {gamma}{delta} T cell-mediated cytotoxicity compared to HPV-transformed organoids and cancerous organoids. To identify the underlying pathways involved in this observed cytotoxicity, we performed bulk-RNA sequencing on the organoid lines, revealing differences in DNA-damage and cell cycle checkpoint pathways, as well as transcription of potential {gamma}{delta} T cell ligands. We validated these results using immunoblotting and flow cytometry. We also demonstrated the involvement of BTN3A1 and BTN2A1, crucial molecules for {gamma}{delta} T cell activation, as well as differential expression of PDL1/CD274 in cancer, E6/E7+ and healthy organoids. Interestingly, we observed a significant reduction in cytotoxicity upon blocking MSH2, a protein involved in DNA mismatch-repair. In summary, we established a co-culture system of {gamma}{delta} T cells with cervical cancer organoids, providing a novel in vitro model to optimize innovative patient-specific immunotherapies for cervical cancer.

immunology↗

bioRxiv2023

The domed architecture of Giardias ventral disc is necessary for attachment and host pathogenesis

After ingestion of dormant cysts, the widespread protozoan parasite Giardia lamblia colonizes the host gastrointestinal tract via direct and reversible attachment using a novel microtubule organelle, the ventral disc. Extracellular attachment to the host allows the parasite to resist peristaltic flow, facilitates colonization and is proposed to cause damage to the microvilli of host enterocytes as well as disrupt host barrier integrity. The 9 {micro}m in diameter ventral disc is defined by a highly complex architecture of unique protein complexes scaffolded onto a spiral microtubule (MT) array of one hundred parallel, uniformly spaced MT polymers that bend approximately one and a quarter turns to form a domed structure. To investigate the role of disc-mediated attachment in causing epithelial cell damage, we used a new approach to rapidly create a stable quadruple knockout of Giardia of an essential ventral disc protein, MBP, using a new method of CRISPR-mediated gene disruption with multiple positive selectable markers. MBP quadruple KO mutant discs lack the characteristic domed architecture and possess a flattened "crescent" or horseshoe-shaped conformation that lacks the overlapping region, with severe defects in the microribbon-crossbridge (MR-CB) complex structure. MBP KO mutants are also unable to resist fluid flow required for attachment to inert surfaces. Importantly, MBP KO mutants have 100% penetrance off positive selection, which is essential for quantification of in vivo impacts of disc and attachment mutants with host cells. Using a new gastrointestinal organoid model of pathogenesis, we found that MBP KO infections had a significantly reduced ability to cause the barrier breakdown characteristic of wild-type infections. Overall, this work provides direct evidence of the role of MBP in creating the domed disc, as well as the first direct evidence that parasite attachment is necessary for host pathology, specifically epithelial barrier breakdown.

microbiology↗

bioRxiv2020

Dissection of barrier dysfunction in organoid-derived human intestinal epithelia induced by Giardia duodenalis

Background and aimsThe protozoa Giardia duodenalis is a major cause of gastrointestinal illness worldwide, but underlying pathophysiological mechanisms remain obscure, partly due to the absence of adequate cellular models. We aimed to overcome these limitations and to recapitulate the authentic series of events in the primary human duodenal tissue by using the human organoid system. MethodsWe established a compartmentalized cellular transwell system with electrophysiological and barrier properties akin to duodenal mucosa and dissected the events leading to G. duodenalis-induced barrier breakdown by functional analysis of transcriptional, electrophysiological and tight junction components. ResultsOrganoid-derived cell layers of different donors showed a time- and parasite load-dependent leak flux indicated by collapse of epithelial barrier upon G. duodenalis infection. Transcriptomic analysis suggested major expression changes in genes contributing to ion transport and tight junction structure. SLC12A2/NKCC1- and CFTR-dependent chloride secretion was reduced early after infection, while changes in the tight junction composition, localization and structural organization occurred later as revealed by immunofluorescence analysis and freeze fracture electron microscopy. ConclusionData suggest a previously unknown sequence of events culminating in intestinal barrier dysfunction upon G. duodenalis infection ignited by alterations of cellular ion transport followed by breakdown of the tight junctional complex and loss of epithelial integrity. The newly established organoid-derived model to study G. duodenalis infection will help enable further molecular dissection of the disease mechanism and, thus, can help to find new options treating disease and infection, in particular relevant for chronic cases of giardiasis.

microbiology↗

bioRxiv2019

Direct antiviral activity of interferon stimulated genes is responsible for resistance to paramyxoviruses in ISG15-deficient cells

Interferons (IFNs), produced during viral infections, induce the expression of hundreds of IFN- stimulated genes (ISGs). Some ISGs have specific antiviral activity while others regulate the cellular response. Besides functioning as an antiviral effector, IFN-stimulated gene 15 (ISG15) is a negative regulator of IFN signalling and inherited ISG15-deficiency leads to autoinflammatory interferonopathies where individuals exhibit elevated ISG expression in the absence of pathogenic infection. We have recapitulated these effects in cultured human A549-ISG15-/- cells and (using A549-UBA7-/- cells) confirmed that posttranslational modification by ISG15 (ISGylation) is not required for regulation of the type-I IFN response. ISG15-deficient cells pre-treated with IFN- were resistant to paramyxovirus infection. We also showed that IFN- treatment of ISG15-deficient cells led to significant inhibition of global protein synthesis leading us to ask whether resistance was due to the direct antiviral activity of ISGs or whether cells were non-permissive due to translation defects. We took advantage of the knowledge that IFN-induced protein with tetratricopeptide repeats 1 (IFIT1) is the principal antiviral ISG for parainfluenza virus 5 (PIV5). Knockdown of IFIT1 restored PIV5 infection in IFN--pre-treated ISG15-deficient cells, confirming that resistance was due to the direct antiviral activity of the IFN response. However, resistance could be induced if cells were pre-treated with IFN- for longer times, presumably due to inhibition of protein synthesis. These data show that the cause of virus resistance is two-fold; ISG15-deficiency leads to the early over-expression of specific antiviral ISGs, but the later response is dominated by an unanticipated, ISG15- dependent, loss of translational control. Key pointsCell culture model of ISG15-deficiency replicate findings in ISG15-/- patient cells Cause of resistance in ISG15-/- cells differs depending on duration of IFN treatment ISG15-/- patients without serious viral disease dont prove ISGylation is unimportant

immunology↗