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The phenomenon of the privacy paradox states that people are concerned about their data, but do not behave accordingly by avoiding disclosure of personal data, for instance, when using social media. Since findings about the influence of privacy concerns on privacy-related behavior are controversial, the present study investigates whether social norms or individual privacy concerns provide a better explanation of disclosure behavior. Therefore, a social media app dummy was developed and the social norm manipulated by altering the amount and the sensitivity of information provided in a fictitious app user profile. Regarding social norm factors, the results of the online experiment (N = 42) revealed that only the sensitivity of the data in the dummy profile demonstrated a medium effect on the amount of personal data given by the participants. Considering individual factors, the less concerned individuals were about their privacy, the higher were the amount and the degree of sensitivity of the personal information participants disclosed. In addition, participants differentiated between sensitive or non-sensitive information when disclosing their data. They disclosed sensitive information significantly less often, regardless of the dummy profile they saw. Altogether, the study results do not support the privacy paradox and demonstrate implications for media education.

Background: Cancer-associated cachexia (CAC) is a metabolic syndrome contributing to therapy resistance and mortality in lung cancer patients (LCP). CAC is typically defined using clinical non-imaging criteria. Given the metabolic underpinnings of CAC and the ability of [ 18 F]fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)/computer tomography (CT) to provide quantitative information on glucose turnover, we evaluate the usefulness of whole-body (WB) PET/CT imaging, as part of the standard diagnostic workup of LCP, to provide additional information on the onset or presence of CAC., Methods: This multi-centre study included 345 LCP who underwent WB [ 18 F]FDG-PET/CT imaging for initial clinical staging. A weight loss grading system (WLGS) adjusted to body mass index was used to classify LCP into 'No CAC' (WLGS-0/1 at baseline prior treatment and at first follow-up: N = 158, 51F/107M), 'Dev CAC' (WLGS-0/1 at baseline and WLGS-3/4 at follow-up: N = 90, 34F/56M), and 'CAC' (WLGS-3/4 at baseline: N = 97, 31F/66M). For each CAC category, mean standardized uptake values (SUV) normalized to aorta uptake (aorta >) and CT-defined volumes were extracted for abdominal and visceral organs, muscles, and adipose-tissue using automated image segmentation of baseline [ 18 F]FDG-PET/CT images. Imaging and non-imaging parameters from laboratory tests were compared statistically. A machine-learning (ML) model was then trained to classify LCP as 'No CAC', 'Dev CAC', and 'CAC' based on their imaging parameters. SHapley Additive exPlanations (SHAP) analysis was employed to identify the key factors contributing to CAC development for each patient., Results: The three CAC categories displayed multi-organ differences in aorta >. In all target organs, aorta > was higher in the 'CAC' cohort compared with 'No CAC' (P < 0.01), except for liver and kidneys, where aorta > in 'CAC' was reduced by 5%. The 'Dev CAC' cohort displayed a small but significant increase in aorta > of pancreas (+4%), skeletal-muscle (+7%), subcutaneous adipose-tissue (+11%), and visceral adipose-tissue (+15%). In 'CAC' patients, a strong negative Spearman correlation (ρ = -0.8) was identified between aorta > and volumes of adipose-tissue. The machine-learning model identified 'CAC' at baseline with 81% of accuracy, highlighting aorta > of spleen, pancreas, liver, and adipose-tissue as most relevant features. The model performance was suboptimal (54%) when classifying 'Dev CAC' versus 'No CAC'., Conclusions: WB [ 18 F]FDG-PET/CT imaging reveals groupwise differences in the multi-organ metabolism of LCP with and without CAC, thus highlighting systemic metabolic aberrations symptomatic of cachectic patients. Based on a retrospective cohort, our ML model identified patients with CAC with good accuracy. However, its performance in patients developing CAC was suboptimal. A prospective, multi-centre study has been initiated to address the limitations of the present retrospective analysis., (© 2024 The Author(s). Journal of Cachexia, Sarcopenia and Muscle published by Wiley Periodicals LLC.)

Background: Suicide bereavement increases the probability of adverse outcomes related to grief, social functioning, mental health, and suicidal behavior. While more support for individuals bereaved by suicide has become available, the evidence regarding its effectiveness is not straightforward. The literature suggests that identifying best-practice components is key in designing effective postvention interventions. Aims: This metareview aims to identify components of suicide bereavement interventions perceived to be effective by suicide-bereaved people. Method: The review adhered to preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Systematic searches in Medline, PsycINFO, Embase, Emcare, EBM Reviews, Scopus, and Web of Science identified 11 eligible systematic reviews published between 2008 and 2023. The methodological quality was assessed using the Measurement Tool to Assess Systematic Reviews (AMSTAR-2) (PROSPERO registration CRD42023458300). Results: Our narrative synthesis reported the components perceived to be effective in relation to structure and content of interventions, facilitators, and modality (peer, group, community, online). Limitations: The quality of the included reviews varied considerably, and not all reviews reported on perceived effectiveness of interventions' components. Meta-analysis of findings was not possible due to study heterogeneity. Conclusion: The findings provide crucial information for researchers, service providers, and policymakers to enhance the provision of evidence-based support for people bereaved by suicide.

Background: Men at risk for suicide are a challenging population group to reach with suicide prevention strategies. Gatekeepers hold a pivotal role in the prevention of male suicide, yet effective intervention requires them to have a level of knowledge and strategies to provide support., Aim: This study aimed to examine the efficacy of an online gatekeeper program for gatekeepers in male suicide prevention, assessing knowledge, perceived preparedness, self-efficacy, and psychopathological symptoms of gatekeepers., Methods: Eighty-four participants were randomized to either the intervention (n = 43) or the waitlist control group (n = 41). The intervention comprised four modules providing knowledge and strategies for addressing men in suicidal crises. Outcomes included depression (PHQ-9), distress (PSS-10), burden (BAS), involvement (IEQ), as well as gatekeeper outcomes and knowledge., Results: Completer analyses revealed significant improvement of depressive symptoms (d = 0.39) and an increase in gatekeeper outcomes (d = 0.58 to d = 0.84) and knowledge (d = 0.62) from baseline to post-assessment. The effects were maintained for 3 months. No significant effects could be found for burden, distress, and involvement., Conclusions: The findings indicate that a brief gatekeeper program can serve as a valuable resource. Future research should focus on examining the mental health of gatekeepers themselves and its long-term effects on intervention behavior., Trial Registration: German Clinical Trials Register, DRKS00030758, registered on 05.12.2022., (© 2024. The Author(s).)

Background: Exosomes are closely associated with different aspects of tumor-progression in patients with head and neck squamous cell carcinoma (HNSCC), such as angiogenesis or immune regulation. As extracellular vesicles they are involved in the intercellular communication by transferring their cargo such as proteins and nucleic acids from one cell to another. However, the influence of tumor related plasma-derived exosomes on the polarization and characteristics of monocyte derived macrophages is not fully understood., Methods: Exosomes were isolated from plasma samples of healthy donors (HD) and HNSCC patients and further evaluated with regard to morphology, size and protein composition via transmission electron microscopy, nanoparticle tracking, western blot analysis and cytokine assays. Differentiation and characteristics of monocyte derived macrophages upon exosome internalization were analyzed using flow cytometry and fluorescence microscopy. Macrophage cytokine secretion patterns were analyzed by human cytokine antibody arrays and ELISA measurements., Results: Our data revealed elevated overall plasma levels of CTLA-4, PD-L1, and TIM-3 as well as elevated exosome-associated CTLA-4, PD-L2, TIM-3, and LAG-3 levels in HNSCC patients compared to HD. Furthermore, we observed a significant type 2-like polarization and elevated CXCL4 secretion of monocyte derived macrophages upon internalization of plasma-derived exosomes from HNSCC patients, which could be visualized by fluorescence microcopy of membrane stained exosomes., Conclusions: The study provides new insights regarding exosome driven pro-tumorigenic immune regulation in the circulation of patients with head and neck cancer and could help to better understand the individual immunologic situation., (© 2024. The Author(s).)

Background: Physician-assisted suicide (PAS) and voluntary euthanasia remain highly debated topics in society, drawing attention due to their ethical, legal, and emotional complexities. Within this debate, the loss of a loved one through suicide may shape the attitudes of survivors, resulting in more or less favorable attitudes towards this topic., Aims: This study aims to explore and compare the attitudes towards PAS and voluntary euthanasia in a population of suicide loss survivors and the general population, while also considering socio-demographic factors., Methods: A total of 529 participants, 168 of whom were survivors of suicide loss, completed an online questionnaire on their attitudes (NOBAS) and opinions (open response format) towards PAS and voluntary euthanasia, as well as regarding their legalization in Germany. The analysis consisted of both quantitative and qualitative components., Results: The entire sample showed positive attitudes towards PAS and voluntary euthanasia in terminally ill persons. Participants were more divided in their attitudes towards PAS in the case of a mental health disorder. Individuals without experienced suicide loss were more liberal regarding legalization in Germany and were more likely to understand the wish for PAS. Survivors of suicide loss were mainly concerned about the consequences for relatives. However, differences between both groups are small., Discussion: The experience of a loss by suicide influences attitudes towards PAS and voluntary euthanasia. Both groups showed an accepting attitude towards PAS and voluntary euthanasia, but also expressed concerns and fears regarding easy accessibility and consequences for grieving relatives., (© 2024. The Author(s).)

In-cell electron paramagnetic resonance (EPR) spectroscopy experiments provide high-resolution data about conformational changes of proteins within the cell. However, one of the limitations of EPR is the requisite of stable paramagnetic centers in a reducing environment. We recently showed that histidine-rich sites in proteins hold a high affinity to Cu(II) ions complexed with a chelator. Using a chelator prevents the reduction of Cu(II) ions. Moreover, this spin-labeling methodology can be performed within the native cellular environment on any overexpressed protein without protein purification and delivery to the cell. Herein, we use this novel methodology to gain spatial information on the extracellular domain of the human copper transporter, hCtr1. Limited structural information on the transmembrane domain of the human Ctr1 (hCtr1) was obtained using X-ray crystallography and cryo-EM. However, these structures are missing information on the disordered extracellular domains of hCtr1. Extracellular domains are sensing or interacting with the environment outside of the cell and therefore play an essential role in any transmembrane protein. Especially in hCtr1, the extracellular domain functions as a gating mechanism for copper ions. Here, we performed EPR experiments revealing structural information about the extracellular N-terminal domain of the full-length hCtr1 in vitro and in situ in insect cells and cell membrane fragments. The comparison revealed that the extracellular domains of the in situ and native membrane hCtr1 are further apart than the structure of the purified protein. These method-related differences highlight the significance of studying membrane proteins in their native environment.

Background : Hereditary Hemorrhagic Telangiectasia (HHT) is a genetic disorder leading to frequent bleeding in several organs. As HHT diagnosis is demanding and depends on clinical criteria, liquid biopsy would be beneficial. Exosomes from biofluids are nano-sized vesicles for intercellular communication. Their cargo and characteristics represent biomarkers for many diseases. Here, exosomes of HHT patients were examined regarding their biosignature. Methods : Exosomes were isolated from the plasma of 20 HHT patients and 17 healthy donors (HDs). The total exosomal protein was quantified, and specific proteins were analyzed using Western blot and antibody arrays. Human umbilical vein endothelial cells (HUVECs) co-incubated with exosomes were functionally examined via immunofluorescence, proliferation, and scratch assay. Results : The levels of the angiogenesis-regulating protein Thrombospondin-1 were significantly higher in HHT compared to HD exosomes. Among HHT, but not HD exosomes, a negative correlation between total exosomal protein and soluble Endoglin (sENG) levels was found. Other exosomal proteins (ALK1, ALK5) and the particle concentration significantly correlated with disease severity parameters (total consultations/interventions, epistaxis severity score) in HHT patients. Functionally, HUVECs were able to internalize both HD and HHT exosomes, inducing a similar change in the F-Actin structure and a reduction in migration and proliferation. Conclusions : This study provided first insights into the protein cargo and function of HHT-derived exosomes. The data indicate changes in sENG secretion via exosomes and reveal exosomal Thrombospondin-1 as a potential biomarker for HHT. Several exosomal characteristics were pointed out as potential liquid biomarkers for disease severity, revealing a possible new way of diagnosis and prognosis of HHT.

Electron paramagnetic resonance (EPR) is a powerful tool for elucidating both static and dynamic conformational alterations in macromolecules. However, to effectively utilize EPR for such investigations, the presence of paramagnetic centers, known as spin labels, is required. The process of spin labeling, particularly for nucleotides, typically demands intricate organic synthesis techniques. In this study, we introduce a unique addition-elimination reaction method with a simple spin-labeling process, facilitating the monitoring of structural changes within nucleotide sequences. Our investigation focuses on three distinct labeling positions with a DNA sequence, allowing the measurement of distance between two spin labels. The experimental mean distances obtained agreed with the calculated distances, underscoring the efficacy of this straightforward spin-labeling approach in studying complex biological processes such as transcription mechanism using EPR measurements., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Bacteria use specialized proteins, like transcription factors, to rapidly control metal ion balance. CueR is a Gram-negative bacterial copper regulator. The structure of E. coli CueR complexed with Cu(I) and DNA was published, since then many studies have shed light on its function. However, P. aeruginosa CueR, which shows high sequence similarity to E. coli CueR, has been less studied. Here, we applied room-temperature electron paramagnetic resonance (EPR) measurements to explore changes in dynamics of P. aeruginosa CueR in dependency of copper concentrations and interaction with two different DNA promoter regions. We showed that P. aeruginosa CueR is less dynamic than the E. coli CueR protein and exhibits much higher sensitivity to DNA binding as compared to its E. coli CueR homolog. Moreover, a difference in dynamical behavior was observed when P. aeruginosa CueR binds to the copZ2 DNA promoter sequence compared to the mexPQ-opmE promoter sequence. Such dynamical differences may affect the expression levels of CopZ2 and MexPQ-OpmE proteins in P. aeruginosa. Overall, such comparative measurements of protein-DNA complexes derived from different bacterial systems reveal insights about how structural and dynamical differences between two highly homologous proteins lead to quite different DNA sequence-recognition and mechanistic properties., (© 2024 The Authors. ChemBioChem published by Wiley-VCH GmbH.)

Introduction: The human leukocyte antigen complex (HLA) is essential for inducing specific immune responses to cancer by presenting tumor-associated peptides (TAP) to T cells. Overexpressed tumor associated antigens, mainly cancer-testis antigens (CTA), are outlined as essential targets for immunotherapy in oropharyngeal squamous cell carcinoma (OPSCC). This study assessed the degree to which presentation, gene expression, and antibody response (AR) of TAP, mainly CTA, are correlated in OPSCC patients to evaluate their potential as immunotherapy targets., Materials and Methods: Snap-frozen tumor (N Ligand/RNA =40), healthy mucosa (N RNA =6), and healthy tonsils (N Ligand =5) samples were obtained. RNA-Seq was performed using Illumina HiSeq 2500/NovaSeq 6000 and whole exome sequencing (WES) utilizing NextSeq500. HLA ligands were isolated from tumor tissue using immunoaffinity purification, UHPLC, and analyzed by tandem MS. Antibodies were measured in serum (N Ab =27) utilizing the KREX™ CT262 protein array. Data analysis focused on 312 proteins (KREX™ CT262 panel + overexpressed self-proteins)., Results: 183 and 94 of HLA class I and II TAP were identified by comparative profiling with healthy tonsils. Genes from 26 TAP were overexpressed in tumors compared to healthy mucosa (LFC>1; FDR<0.05). Low concordance (r=0.25; p<0.0001) was found between upregulated mRNA and class I TAP. The specific mode of correlation of TAP was found to be dependent on clinical parameters. A lack of correlation was observed both between mRNA and class II TAP, as well as between class II tumor-unique TAP (TAP-U) presentation and antibody response (AR) levels., Discussion: This study demonstrates that focusing exclusively on gene transcript levels fails to capture the full extent of TAP presentation in OPSCC. Furthermore, our findings reveal that although CTA are presented at relatively low levels, a few CTA TAP-U show potential as targets for immunotherapy., Competing Interests: SL: Advisory Boards: Merck Sharp & Dohme MSD, Bristol Myers Squibb BMS, Sanofi Genzyme, Astra Zeneca AZ. Honoraria: MSD, BMS. Travel reimbursement: Merck Serono, Astra Zeneca. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Abou Kors, Meier, Mühlenbruch, Betzler, Oliveri, Bens, Thomas, Kraus, Doescher, von Witzleben, Hofmann, Ezic, Huber, Benckendorff, Barth, Greve, Schuler, Brunner, Blackburn, Hoffmann, Ottensmeier, Kestler, Rammensee, Walz and Laban.)

Purpose: Primary central nervous system (CNS) gliomas can be classified by characteristic genetic alterations. In addition to solid tissue obtained via surgery or biopsy, cell-free DNA (cfDNA) from cerebrospinal fluid (CSF) is an alternative source of material for genomic analyses., Experimental Design: We performed targeted next-generation sequencing of CSF cfDNA in a representative cohort of 85 patients presenting at two neurooncological centers with suspicion of primary or recurrent glioma. Copy-number variation (CNV) profiles, single-nucleotide variants (SNV), and small insertions/deletions (indel) were combined into a molecular-guided tumor classification. Comparison with the solid tumor was performed for 38 cases with matching solid tissue available., Results: Cases were stratified into four groups: glioblastoma (n = 32), other glioma (n = 19), nonmalignant (n = 17), and nondiagnostic (n = 17). We introduced a molecular-guided tumor classification, which enabled identification of tumor entities and/or cancer-specific alterations in 75.0% (n = 24) of glioblastoma and 52.6% (n = 10) of other glioma cases. The overlap between CSF and matching solid tissue was highest for CNVs (26%-48%) and SNVs at predefined gene loci (44%), followed by SNVs/indels identified via uninformed variant calling (8%-14%). A molecular-guided tumor classification was possible for 23.5% (n = 4) of nondiagnostic cases., Conclusions: We developed a targeted sequencing workflow for CSF cfDNA as well as a strategy for interpretation and reporting of sequencing results based on a molecular-guided tumor classification in glioma. See related commentary by Abdullah, p. 2860., (©2024 The Authors; Published by the American Association for Cancer Research.)

Acute myeloid leukemia (AML) is a heterogenous disease characterized by the clonal expansion of myeloid progenitor cells. Despite recent advancements in the treatment of AML, relapse still remains a significant challenge, necessitating the development of innovative therapies to eliminate minimal residual disease. One promising approach to address these unmet clinical needs is natural killer (NK) cell immunotherapy. To implement such treatments effectively, it is vital to comprehend how AML cells escape the NK-cell surveillance. Signal transducer and activator of transcription 3 (STAT3), a component of the Janus kinase (JAK)-STAT signaling pathway, is well-known for its role in driving immune evasion in various cancer types. Nevertheless, the specific function of STAT3 in AML cell escape from NK cells has not been deeply investigated. In this study, we unravel a novel role of STAT3 in sensitizing AML cells to NK-cell surveillance. We demonstrate that STAT3-deficient AML cell lines are inefficiently eliminated by NK cells. Mechanistically, AML cells lacking STAT3 fail to form an immune synapse as efficiently as their wild-type counterparts due to significantly reduced surface expression of intercellular adhesion molecule 1 (ICAM-1). The impaired killing of STAT3-deficient cells can be rescued by ICAM-1 overexpression proving its central role in the observed phenotype. Importantly, analysis of our AML patient cohort revealed a positive correlation between ICAM1 and STAT3 expression suggesting a predominant role of STAT3 in ICAM-1 regulation in this disease. In line, high ICAM1 expression correlates with better survival of AML patients underscoring the translational relevance of our findings. Taken together, our data unveil a novel role of STAT3 in preventing AML cells from escaping NK-cell surveillance and highlight the STAT3/ICAM-1 axis as a potential biomarker for NK-cell therapies in AML., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Witalisz-Siepracka, Denk, Zdársky, Hofmann, Edtmayer, Harm, Weiss, Heindl, Hessenberger, Summer, Dutta, Casanova, Obermair, Győrffy, Putz, Sill and Stoiber.)

Suicide-bereaved individuals are often confronted with profound grief reactions and have an increased risk for mental health disorders. Little is known about the development of complex post-traumatic stress disorder (CPTSD) following a loss by suicide. This paper aims to assess the prevalence of CPTSD, PTSD, prolonged grief disorder (PGD), and depression as well as to identify sociodemographic and loss-related factors regarding their development. A total of 161 suicide loss survivors (91.3% female) completed a questionnaire, which collected symptoms of grief (TGI-SR+), PTSD, CPTSD (ITQ), and depression (PHQ-D). In total, 12.4% met the diagnosis for CPTSD, 5.0% for PTSD. A total of 22.0% fulfilled the diagnosis for PGD. 41.6% showed at least moderate symptoms of depression. Pearson's correlation showed that time since loss was negatively associated with PG and PTSD symptoms, kinship to the deceased was associated with PG severity. The sample scored high on all disturbances in self-organization (DSO) symptom clusters typical for CPTSD. A focus on symptoms of CPTSD may be a necessary component in the care of survivors of suicide loss.

Background: Head and neck squamous cell carcinoma (HNSCC) represents a common and heterogeneous malignancy of the oral cavity, pharynx and larynx. Surgery and radio(chemo)therapy are the standard treatment options and also have great influence on the composition of the tumor microenvironment and immune cell functions. However, the impact of radio(chemo)therapy on the distribution and characteristics of circulating monocyte subsets in HNSCC are not fully understood., Methods: Expression patterns of adhesion molecules and chemokine receptors CD11a (integrin-α L; LFA-1), CD11b (integrin-α M; Mac-1), CD11c (integrin-α X), CX3CR1 (CX3CL1 receptor) and checkpoint molecule PD-L1 (programmed cell death ligand-1) were investigated upon radio(chemo)therapeutic treatment using flow cytometry. Furthermore, comprehensive analysis of plasma cytokines was performed before and after treatment using ELISA measurements., Results: Our data reveal a partial recovery of circulating monocytes in HNSCC patients upon radio(chemo)therapeutic treatment, with differential effects of the individual therapy regimen. PD-L1 expression on non-classical monocytes significantly correlates with the individual plasma levels of chemokine CXCL11 (C-X-C motif chemokine 11)., Conclusions: Further comprehensive investigations on larger patient cohorts are required to elucidate the meaningfulness of peripheral blood monocyte subsets and chemokine CXCL11 as potential bioliquid indicators in HNSCC with regard to therapy response and the individual immunological situation., (© 2024. The Author(s).)

Fabry disease (FD) is a lysosomal storage disorder of X-linked inheritance. Mutations in the α-galactosidase A gene lead to cellular globotriaosylceramide (Gb3) depositions and triggerable acral burning pain in both sexes as an early FD symptom of unknown pathophysiology. We aimed at elucidating the link between skin cells and nociceptor sensitization contributing to FD pain in a sex-associated manner. We used cultured keratinocytes and fibroblasts of 27 adult FD patients and 20 healthy controls. Epidermal keratinocytes and dermal fibroblasts were cultured and immunoreacted to evaluate Gb3 load. Gene expression analysis of pain-related ion channels and pro-inflammatory cytokines was performed in dermal fibroblasts. We further investigated electrophysiological properties of induced pluripotent stem cell (iPSC) derived sensory-like neurons of a man with FD and a healthy man and incubated the cells with interleukin 8 (IL-8) or fibroblast supernatant as an in vitro model system. Keratinocytes displayed no intracellular, but membrane-bound Gb3 deposits. In contrast, fibroblasts showed intracellular Gb3 and revealed higher gene expression of potassium intermediate/small conductance calcium-activated potassium channel 3.1 (KCa 3.1, KCNN4) in both, men and women with FD compared to controls. Additionally, cytokine expression analysis showed increased IL-8 RNA levels only in female FD fibroblasts. Patch-clamp studies revealed reduced rheobase currents for both iPSC neuron cell lines incubated with IL-8 or fibroblast supernatant of women with FD. We conclude that Gb3 deposition in female FD patient skin fibroblasts may lead to increased KCa3.1 activity and IL-8 secretion. This may result in cutaneous nociceptor sensitization as a potential mechanism contributing to a sex-associated FD pain phenotype., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Hofmann et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Acral burning pain triggered by fever, thermal hyposensitivity and skin denervation are hallmarks of small fibre neuropathy in Fabry disease, a life-threatening X-linked lysosomal storage disorder. Variants in the gene encoding alpha-galactosidase A may lead to impaired enzyme activity with cellular accumulation of globotriaosylceramide. To study the underlying pathomechanism of Fabry-associated small fibre neuropathy, we generated a neuronal in vitro disease model using patient-derived induced pluripotent stem cells from three Fabry patients and one healthy control. We further generated an isogenic control line via gene editing. We subjected induced pluripotent stem cells to targeted peripheral neuronal differentiation and observed intra-lysosomal globotriaosylceramide accumulations in somas and neurites of Fabry sensory neurons using super-resolution microscopy. At functional level, patch-clamp analysis revealed a hyperpolarizing shift of voltage-gated sodium channel steady-state inactivation kinetics in isogenic control neurons compared with healthy control neurons ( P < 0.001). Moreover, we demonstrate a drastic increase in Fabry sensory neuron calcium levels at 39°C mimicking clinical fever ( P < 0.001). This pathophysiological phenotype was accompanied by thinning of neurite calibres in sensory neurons differentiated from induced pluripotent stem cells derived from Fabry patients compared with healthy control cells ( P < 0.001). Linear-nonlinear cascade models fit to spiking responses revealed that Fabry cell lines exhibit altered single neuron encoding properties relative to control. We further observed mitochondrial aggregation at sphingolipid accumulations within Fabry sensory neurites utilizing a click chemistry approach together with mitochondrial dysmorphism compared with healthy control cells. We pioneer pilot insights into the cellular mechanisms contributing to pain, thermal hyposensitivity and denervation in Fabry small fibre neuropathy and pave the way for further mechanistic in vitro studies in Fabry disease and the development of novel treatment approaches., Competing Interests: The authors report no competing interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)