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Hydrogen Peroxide (H2O2) is a central oxidant in redox biology due to its pleiotropic role in physiology and pathology. However, real-time monitoring of H2O2 in living cells and tissues remains a challenge. We address this gap with the development of an optogenetic hydRogen perOxide Sensor (oROS), leveraging the bacterial peroxide binding domain OxyR. Previously engineered OxyR-based fluorescent peroxide sensors lack the necessary sensitivity and response speed for effective real-time monitoring. By structurally redesigning the fusion of Escherichia coli (E. coli) ecOxyR with a circularly permutated green fluorescent protein (cpGFP), we created a novel, green-fluorescent peroxide sensor oROS-G. oROS-G exhibits high sensitivity and fast on-and-off kinetics, ideal for monitoring intracellular H2O2 dynamics. We successfully tracked real-time transient and steady-state H2O2 levels in diverse biological systems, including human stem cell-derived neurons and cardiomyocytes, primary neurons and astrocytes, and mouse brain ex vivo and in vivo. These applications demonstrate oROS’s capabilities to monitor H2O2 as a secondary response to pharmacologically induced oxidative stress and when adapting to varying metabolic stress. We showcased the increased oxidative stress in astrocytes via A?-putriscine-MAOB axis, highlighting the sensor’s relevance in validating neurodegenerative disease models. Lastly, we demonstrated acute opioid-induced generation of H2O2 signal in vivo which highlights redox-based mechanisms of GPCR regulation. oROS is a versatile tool, offering a window into the dynamic landscape of H2O2 signaling. This advancement paves the way for a deeper understanding of redox physiology, with significant implications for understanding diseases associated with oxidative stress, such as cancer, neurodegenerative, and cardiovascular diseases.

To facilitate the characterization of unlabeled induced pluripotent stem cells (iPSCs) during culture and expansion, we developed an AI pipeline for nuclear segmentation and mitosis detection from phase contrast images of individual cells within iPSC colonies. The analysis uses a 2D convolutional neural network (U-Net) plus a 3D U-Net applied on time lapse images to detect and segment nuclei, mitotic events, and daughter nuclei to enable tracking of large numbers of individual cells over long times in culture. The analysis uses fluorescence data to train models for segmenting nuclei in phase contrast images. The use of classical image processing routines to segment fluorescent nuclei precludes the need for manual annotation. We optimize and evaluate the accuracy of automated annotation to assure the reliability of the training. The model is generalizable in that it performs well on different datasets with an average F1 score of 0.94, on cells at different densities, and on cells from different pluripotent cell lines. The method allows us to assess, in a non-invasive manner, rates of mitosis and cell division which serve as indicators of cell state and cell health. We assess these parameters in up to hundreds of thousands of cells in culture for more than 36 hours, at different locations in the colonies, and as a function of excitation light exposure.

BackgroundTimely resolution of innate immune responses activated by surgical intervention is crucial for patient recovery. While cytokines and innate immune cells are critical in inflammation resolution, the specific role of IL-18 in these processes remains controversial and underexplored.MethodsWe investigate determinants of successful recovery using peripheral blood samples from orthopedic surgery (ORT) patients (n?=?33) at T0 (before surgery), T1 (24 h after surgery) and T2 (3 days after surgery). Monocytes from ORT patients underwent immunophenotyping together with bulk transcriptomic analysis. We found that IL-18 strongly defines the recovery immune signature. These results were further validated in vitro by comparing IL-18 and TNF-? effects on monocytes, and in 3D human intestine organoids together with single cell (sc)-RNAseq analysis.ResultsTranscriptomics of ORT monocytes revealed upregulation of ITG family integrins, namely ITGB3 and ITGB5, CXCL family chemokines, notably CXCL1-3, CXCL5, and SCL/TAL1 factor controlling differentiation and migration, but not pro-inflammatory genes. Similar changes were observed in IL-18 stimulated healthy donor monocytes in vitro, including an increase in CD11b, CD64, and CD86 levels, accompanied by increased phosphorylation of Akt but not NF?B. These changes were attenuated in the presence of TNF-?, thus showing a unique role of IL-18 when acting alone without its most frequent paired cytokine TNF-?. We further confirmed that IL-18 induces monocyte-macrophage transition and migration using human intestinal organoids. Finally, TNF-?/IL-18 ratio showed a high predictive value of clinical severity in septic patients.ConclusionsWe propose a novel role of IL-18 on monocyte migration and macrophage transition characterizing successful orthopedic surgery recovery, as well as the ratio of IL-18/TNF-? as a novel marker of inflammation resolution, with potential implications for patient monitoring and therapeutic strategies.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12967-025-06652-7.

Parkinson’s disease (PD) is a debilitating neurodegenerative disease characterized by the loss of midbrain dopaminergic neurons (DaNs) and the abnormal accumulation of ?-Synuclein (?-Syn) protein. Currently, no treatment can slow nor halt the progression of PD. Multiplications and mutations of the ?-Syn gene (SNCA) cause PD-associated syndromes and animal models that overexpress ?-Syn replicate several features of PD. Decreasing total ?-Syn levels, therefore, is an attractive approach to slow down neurodegeneration in patients with synucleinopathy. We previously performed a genetic screen for modifiers of ?-Syn levels and identified CDK14, a kinase of largely unknown function as a regulator of ?-Syn. To test the potential therapeutic effects of CDK14 reduction in PD, we ablated Cdk14 in the ?-Syn preformed fibrils (PFF)-induced PD mouse model. We found that loss of Cdk14 mitigates the grip strength deficit of PFF-treated mice and ameliorates PFF-induced cortical ?-Syn pathology, indicated by reduced numbers of pS129 ?-Syn-containing cells. In primary neurons, we found that Cdk14 depletion protects against the propagation of toxic ?-Syn species. We further validated these findings on pS129 ?-Syn levels in PD patient neurons. Finally, we leveraged the recent discovery of a covalent inhibitor of CDK14 to determine whether this target is pharmacologically tractable in vitro and in vivo. We found that CDK14 inhibition decreases total and pathologically aggregated ?-Syn in human neurons, in PFF-challenged rat neurons and in the brains of ?-Syn-humanized mice. In summary, we suggest that CDK14 represents a novel therapeutic target for PD-associated synucleinopathy.