Biology subjects

Nowak, E.

Publications and source records attributed to Nowak, E..

5 recordsLinked to original sources

bioRxiv2026

Collateral sensitivities with predictive signatures emerge in a novel model of evolved chemoresistance in osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. Despite aggressive multimodal therapy, including surgery and chemotherapy with methotrexate, doxorubicin, and cisplatin (MAP), outcomes for patients with relapsed or refractory disease remain poor, with no standardized second-line regimen. We developed a clinically calibrated, temporally resolved in vitro model to examine how resistance and collateral drug responses evolve during treatment with methotrexate, doxorubicin, and cisplatin (MAP). We modeled the evolution of chemotherapy resistance in vitro by exposing an OS cell line, MG63.3, to clinically relevant cycles of MAP therapy. MAP resistance and collateral drug responses were quantified over time across five independent evolutionary replicates, and three solvent-treated replicates served as controls. We complemented this phenotypic screening with transcriptomic profiling to extract predictive biomarkers of collateral drug response that could be used to personalize second-line treatment in patients with refractory OS. MAP exposure produced progressive resistance to doxorubicin and methotrexate, whereas cisplatin sensitivity remained comparatively stable. Repeated temporal screening against 12 additional drugs and combinations revealed three broad patterns of collateral response: progressive resistance, progressive sensitivity, and non-linear or stochastic change. Etoposide resistance emerged consistently, while sensitivity developed toward palifosfamide-etoposide and gemcitabine-docetaxel. Transcriptomic profiling showed dynamic, replicate-specific evolutionary trajectories rather than a single uniform resistance state. To demonstrate one approach for how our large, paired dataset could be used to translate these findings into potentially actionable clinical tools, we extracted predictive gene expression signatures of collateral drug response. By applying a dynamic, clinically inspired model of chemotherapy resistance in OS, we generated a detailed temporal mapping of collateral drug responses that highlights potential therapeutic windows and can be used inform selection of second-line agents. This approach and the resulting dataset can ultimately support personalized medicine strategies for patients with relapsed or refractory OS.

cancer biology↗

bioRxiv2025

Keratinocyte VISTA attenuates UV light-induced skin injury by suppressing cutaneous type I interferon (IFN-I) response

Persistent production of type I interferons (IFN-Is) is a hallmark of cutaneous lupus erythematosus (CLE). Ultraviolet (UV) light stimulates IFN-I response in the skin and exacerbates CLE. Here, we identify V-type immunoglobulin domain-containing suppressor of T cell activation (VISTA) as a negative regulator of both basal and UV-induced IFN-I responses in the skin and show that VISTA limits skin photosensitivity in an IFN-I- dependent manner, in part through Stimulator of Interferon Genes (STING). Furthermore, we demonstrate a novel role for VISTA in keratinocytes both at steady state and in response to UV light. Conditional deletion of VISTA in epidermal keratinocytes results in >10-fold increase in the basal skin IFN-I score and a heightened UV-induced skin injury score, which is dependent on IFN-I signaling. VISTA-targeting monoclonal antibodies suppress UV-induced IFN-I response in human keratinocytes and in mice expressing human VISTA in vivo, which also reduces UV-induced skin injury score. Our findings highlight VISTA as a potential therapeutic target for suppressing IFN-I responses in cutaneous lupus patients who suffer from UV-induced skin inflammation.

immunology↗

bioRxiv2023

RNA 5' terminal nucleotide determines the strength of the RIG-I/IFN signaling pathway

The interferon (IFN) response is crucial for antiviral activity, but its overstimulation can lead to a wide range of autoimmune disorders. The cytoplasmic pattern recognition receptor RIG-I detects viral double-stranded RNAs (dsRNAs) and endogenous polymerase III transcripts carrying a 5'-triphosphate (5'-ppp) or 5'-diphosphate (5'-pp) moiety, triggering phosphorylation of IRF3 and IFN immune response. While many viral RNAs initiate with 5'-ppp-adenosine (5'-pppA) and most endogenous Pol III transcripts in higher eukaryotes start with 5'-ppp-guanosine (5'-pppG), no apparent reason for this bias has been identified so far. Here we demonstrate that dsRNAs initiating with 5'-pppA trigger stronger RIG-I/IFN response than those starting with 5'-pppG. We show that several GTP-binding proteins interact preferentially with 5'-pppG RNAs. Finally, supplementation with guanosine, but not adenosine, which rapidly increases intracellular concentrations of GTP and ATP, respectively, eliminates the difference in immunogenicity between 5'-pppG and 5'-pppA RNAs. Our findings suggest that 5'-pppG RNAs may enable certain RNA viruses and Pol III transcripts to limit detection by innate immune receptors. These results offer new insights into the sequence-dependent activation of the RIG-I/IFN pathway and have important implications for both antiviral immunity and the role of Pol III-derived RNAs in autoimmune diseases.

molecular biology↗

bioRxiv2022

Structure of human TRPM8 channel.

SUMMARYTRPM8 is a calcium ion channel that is activated by multiple factors, such as temperature, voltage, pressure, and osmolality. It is a therapeutic target for anticancer drug development, and its modulators can be utilized for several pathological conditions. Here, we present a cryo-electron microscopy structure of a human TRPM8 channel in the closed state that was solved at 2.7 [A] resolution. Based on our reconstruction, we built the most complete model of the N-terminal pre-melastatin homology region. We also visualized several ligands that are bound by the protein and modeled how the human channel interacts with icilin. Analyses of pore helices showed that all available TRPM8 structures can be grouped into closed and desensitized states based on the register of pore helix S6 and the resulting positioning of particular amino acid residues at the channel constriction.

molecular biology↗

bioRxiv2020

Morphology and immunhistchemical characteristics of the otic ganglion in chinchilla (Chinchila laniger Molina).

The available literature provides relatively little information on the morphology of the autonomic head ganglia in rodents including their neurochemical codding. The present study was thus designed to investigate the morphology and neurochemical properties of the otic ganglion in the chinchilla. The results will contribute to our knowledge of the organization of the autonomic nerve system in mammals. Morphological investigations of the otic ganglion were performed using the modified acetylcholinesterase method. The cellular structure was investigated with histological techniques and neurochemical properties were studied with double-labelling immunofluorescence method Macromorphological investigations allowed the otic ganglion to be identified as a compact, oval agglomeration of neurons and nerve fibers located inside the skull on the medial surface of the mandibular nerve, just above the oval foramen. Multidimensional cross-sections revealed densely arranged neuronal perikarya and two populations of nerve cells differing in size were distinguished. The large cells (40-50 m) accounted for about 80% of the neurons in the otic ganglion cross-sections. Moreover, a small number of intraganglionic nerve fibers was observed. Immunohistochemical staining revealed that over 85% of the neuronal cell bodies in the otic ganglion contained immunoreactivity to VAChT or ChAT. VIP-immunoreactive perikarya comprised approximately 10% of the ganglionic cells. Double staining revealed the presence of VAChT and NOS-positive neurons which amounted to about 45% of the nerve cells in the otic ganglion. NOS-positive only perikarya comprised approx. 15% of all the neurons. Immunoreactivity to enkephalin, substance P, somatostatin and galanin was expressed in single nerve cell bodies and nerve fibres except numerous SP-positive intraganglionic nerve fibres. Some of them stained also for CGRP. Single neurons stained for TH. The present results, compared with previous findings, suggest the existence interspecies differences in the morphology, cellular structure and immunohistochemical properties of the head autonomic ganglia in mammals.

neuroscience↗