Biology subjects

Ehsani, M.

Publications and source records attributed to Ehsani, M..

4 recordsLinked to original sources

bioRxiv2026

LemonCatcher Acidic Pull-Down Enables Selective In-Cell Hydrogen-Deuterium Exchange Mass Spectrometry

Proteins are dynamic molecules which sensitively adapt according to their environment. Hydrogen-Deuterium eXchange Mass Spectrometry (HDX-MS) provides unique insights into protein conformational processes. However, existing methodology cannot selectively enrich proteins post-labeling because D-to-H back exchange must be minimized by rapid processing at pH 2.3-3.0 and 0 {degrees}C, where affinity purification fails. Here, we create LemonCatcher, a protein superglue that spontaneously forms an amide bond to the LemonTag peptide under these harsh acidic and cold quench conditions, even at -20 {degrees}C. Engineering of a bead-coupled LemonCatcher purification system introduces fast and selective quench-capture HDX-MS (SelQueX) on LemonTagged fusion proteins. We demonstrate targeted measurement of protein dynamics in living bacterial cells, revealing ligand-induced conformational changes in maltose-binding protein. Moreover, probing a stalled membrane protein nascent-chain supports a role for the ribosome in maintaining partially unfolded folding intermediates. Thus, SelQueX makes possible selective characterization of protein structural dynamics within the complex cellular milieu.

biochemistry↗

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↗