EMBO Molecular Medicine

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of poor prognosis, for which age is the strongest risk factor. Despite significant progress in the discovery of ALS-associated mutations, no model explains how such a diversity of mutations converges in a common pathology. In addition, most ALS cases are sporadic and lack known genetic drivers. We recently reported that arginine-rich peptides arising from the C9ORF72 mutation trigger a widespread accumulation of orphan ribosomal proteins (oRP). Here, we show that oRP accumulation is also observed upon expression of other RNA-related ALS mutations, such as hnRNPA2D290V and TDP-43A315T, as well as upon exposure to the ALS-related neurotoxin {beta}-N-methylamino-L-alanine (BMAA). Furthermore, the transcriptional signature of patients with sporadic ALS resembles that of Diamond-Blackfan anemia (DBA), a known ribosomopathy. Supporting the usefulness of our in vitro data, a transcriptional signature defined from these models provides diagnostic and prognostic value in ALS patients. We propose that the accumulation of oRPs due to dysfunctional ribosome biogenesis is a molecular hallmark of ALS that can contribute to the progressive loss of motor neurons in the disease.

The mechanisms that drive myelin damage as seen in demyelinating disorders such as multiple sclerosis remain incompletely understood. Much of our current knowledge is derived from animal models, but interspecies differences limit their relevance in the context of human pathology and could explain why various promising preclinical therapies failed during clinical translation. Human post-mortem organotypic brain slice cultures provide a unique platform to study human myelin biology, as they preserve genetic, cytoarchitectural, pathological and species-specific context. Here, we evaluated myelin integrity in a human post-mortem brain organotypic slice culture model and experimentally induce focal myelin damage. Human post-mortem organotypic slices cultures retain key features throughout the culturing period, but exhibit gradual cellular and myelin loss over time. Myelin fibres within the white matter remain detectable and present preserved structural and chemical integrity up to 13 days in vitro, indicated by the conserved paranodal and nodal organization and stable myelin spectroscopic signature. Delivery of lysophosphatidylcholine using cryogel scaffolds enables focal drug administration throughout the full depth of the slice with minimal diffusion into surrounding tissue and induces localized demyelination after lysophosphatidylcholine application. Similar focal application of the selective Nav1.6 stimulator {beta}-mammal scorpion toxin Cn2 induces subtle myelin destabilization. Overall, our results demonstrate the suitability of a human post-mortem brain organotypic slice culture model as an adequate platform for studying myelin damage in a human disease context.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is rapidly increasing worldwide, yet effective targeted therapies remain limited. To better understand the molecular mechanisms underlying MASLD, we performed an integrated proteogenomic analysis of human liver tissue. Using mass spectrometry, we quantified 2,744 proteins in 504 liver biopsies from the Quebec Obesity Biobank and examined changes across disease stages. To investigate causality, we integrated liver proteomics with RNA sequencing and genome-wide genotyping to map thousands of protein quantitative trait loci (pQTLs) and expression quantitative trait loci (eQTLs). These molecular data were combined with summary statistics from a meta-analysis of genome-wide association studies including 16,532 MASLD cases and 1,240,188 controls. Mendelian randomization and genetic colocalization analyses revealed that most proteins differentially expressed across MASLD stages were not causally implicated in disease risk, whereas several genetically predicted liver proteins showed evidence of causal effects. Among these, higher hepatic levels of the MTARC1 protein were causally associated with MASLD and hepatic fat accumulation. Phenome-wide analyses suggested that MTARC1 inhibition may reduce the risk of cirrhosis, hepatocellular carcinoma, and cholelithiasis while improving lipid profiles. Notably, the causal MTARC1 variant influenced liver protein levels but not gene expression. Genetic analyses also identified ERLIN1 and HSD17B13 as potential therapeutic targets. In contrast, eQTLs and pQTLs at other loci such as GCKR showed opposite effects on MASLD risk. These findings highlight the importance of integrating tissue proteomics with human genetics to distinguish biomarkers from causal drivers and to identify promising therapeutic targets for MASLD.

Oncogenic MYC transcription factors profoundly alter cellular programs, imposing dependencies that can be therapeutically exploited in MYC-driven cancers such as high-risk neuroblastoma. However, dissecting such synthetic lethal vulnerabilities using controlled, tunable gene expression within a uniform genetic background remains challenging. Widely used tetracycline-regulated systems rely on inducers known to perturb mitochondrial function, introducing significant off-target effects that may confound interpretation. To overcome this limitation, we established novel cumate (p-isopropylbenzoate)-inducible neuroblastoma models that enable physiologically unbiased regulation of MYC(N) expression. Functional validation demonstrated that cumate itself does not induce off-target effects on neuroblastoma cell viability, mitochondrial membrane potential, morphology, proteostasis, or stress signaling, even at the highest recommended dose. The developed SHEP-CuO-MYC and -MYCN models show efficient, titratable, and reversible upregulation of c-MYC and N-MYC, respectively, recapitulating the expression levels observed in MYC(N)-amplified neuroblastoma. As a proof-of-concept, we applied these models to mechanistically validate the recently proposed mitoribosomal synthetic lethality, providing fully unbiased evidence that elevated c-MYC/N-MYC levels sensitize neuroblastoma cells to inhibitors of mitochondrial gene expression. Although impairing mitochondrial translation activated mitochondrial integrated stress response in both MYC-on and MYC-off states, it led to dramatic MYC downregulation coupled with enhanced caspase-dependent cell death in MYC-on cells. These findings reveal that MYC(N) overexpression confers a selective, proliferation-independent mitochondrial vulnerability that can be therapeutically targeted by repurposing well-tolerated mitochondrial ribosome-targeting antibiotics. Collectively, our models provide a robust platform for studying the MYC-mitochondria interplay and can be directly adapted for drug repurposing screens targeting mitochondrial dependencies in neuroblastoma and, potentially, other MYC-driven tumors. HIGHLIGHTSO_LICumate shows no inducer-associated mitochondrial or cytotoxic off-target effects C_LIO_LICumate-inducible MYC models enable mechanistic studies of mitochondrial synthetic lethality C_LIO_LIMYC overexpression drives neuroblastoma sensitivity to mitochondrial translation inhibition C_LIO_LICommon ribosomal antibiotics trigger caspase-dependent cell death in MYC-driven tumor cells C_LIO_LIContext-specific MYC downregulation links mitochondrial stress to MYC synthetic lethality C_LI

Pleural mesothelioma (PM) is a rare, aggressive cancer primarily caused by asbestos exposure and remains resistant to conventional chemotherapy. Although dual immune checkpoint inhibition (anti-PD-1/anti-CTLA-4) is now approved as first-line therapy, clinical benefit is limited to a small subset of patients, necessitating the need for alternative strategies. Oncolytic viruses (OVs) represent a promising approach as they selectively infect and lyse tumor cells while reprogramming the immunosuppressive tumor microenvironment (TME) into an immunostimulatory state. In PM, we previously showed that the attenuated Schwarz strain of measles virus (MV) oncolytic activity is mainly dependent on alterations in the type I interferon (IFN-I) pathway, rendering tumor cells sensitive to infection. Recently, we showed that monocytes/macrophages exposed to MV produce IFN-I, which protects PM cells via paracrine IFNAR signaling. This underscores the necessity of modeling the TME to accurately evaluate OV efficacy. Conventional rodent models are non-permissive to MV, and availability of fresh human PM tissue is scarce. We therefore developed a humanized 3D "vascularized mesothelioma-on-chip" (VMOC) model using microfluidic chips. It comprises two perfusable endothelial-lined parental vessels flanking a central secondary microvascular network (MVN), generated using human umbilical vein endothelial cells (HUVECs) embedded in fibrin and co-cultured alongside PM cells and primary human lung fibroblasts (hLFs). We characterized the integrity and functionality of the endothelial compartment as well as the cellular heterogeneity in VMOC using single-cell RNA sequencing. After administration of MV via the endothelial network, we observed infection and death of PM cells in addition to a strong activation of the type I interferon pathway and production of multiple inflammatory mediators. The VMOC model enables in vitro study of both MV infection and TME reprogramming, paving the way for a better understanding of the role of the TME in the response to treatment and for supporting the development of more personalized, targeted therapies for PM.

Cardiovascular diseases (CVDs) remain the primary global health burden, motivating the search for robust, non-invasive risk biomarkers. We harness a foundation model pretrained on over 10 million recordings, to evaluate ECG-derived age deviation as a cross-cohort biomarker of CVD burden. A predictive model, trained exclusively on healthy subjects, achieved accurate age prediction. Diseased subjects exhibited significant positive age acceleration across multiple categories, with structural and ischemic heart diseases showing the largest effects. External validation in a hospital-based cohort (n=160,493) confirmed that age acceleration independently predicts all-cause mortality, with the strongest prognostic value in patients under 65 years. Furthermore, we demonstrated that disease discrimination and mortality prediction are preserved across 6-lead and single-lead configurations, supporting potential deployment in wearable or mobile devices. Our analysis also revealed a striking morphological confound from the complete left bundle branch block, leading us to propose absolute age deviation as a more robust, universal risk marker. These findings establish ECG-derived biological age deviation as a highly generalizable and clinically actionable biomarker for assessing cardiovascular risk. We have also developed a web application at https://bioinformatics.mdc-berlin.de/ECGage that allows users to easily test our framework.

Mitochondrial dysfunction is a central driver of neonatal hypoxic-ischaemic encephalopathy (HIE), yet the specific vulnerabilities of mitochondrial fusion machinery in the neonatal brain remain poorly defined. Here, we investigate Optic Atrophy (OPA)1 as a critical determinant of mitochondrial resilience during hypoxia-ischaemia (HI). Human developmental transcriptomics showed stable perinatal expression of mitochondrial dynamics genes, supporting their potential utility as therapeutic targets at birth. In a neonatal mouse model, HI induced rapid proteolytic processing of OPA1 in whole brain. In vitro, exposure of primary astrocytes to oxygen-glucose deprivation (OGD) mimicked the OPA1 sensitivity observed in whole brain, with aberrant processing and loss of expression. We genetically replicated this observation by knocking down OPA1 expression in primary astrocytes. The predicted mitochondrial fragmentation and impaired bioenergetics was also accompanied by increased vulnerability to hypoxia, revealing an OPA1dependent susceptibility under moderate metabolic stress. Transcriptomics analyses of these cells highlighted an OPA1-mediated depletion of mitochondrial DNA. This mtDNA depletion was also evident in OGD-treated astrocytes and ex vivo brain samples at 24h after HI in our rodent model. In contrast, mild OPA1 overexpression enhanced astrocyte survival following OGD and OPA1 overexpression in vivo markedly reduced tissue damage after neonatal HI. MtDNA levels in OPA1-overexpressing mice before and at 7 days after HI were significantly higher than in wild-type mice. These findings position OPA1 as a key mediator of mitochondrial impairment after HI and to our knowledge, is the first study showing that loss of mtDNA is a consequence of neonatal HI. Our data highlight that maintaining OPA1 expression is a promising therapeutic strategy for protecting the neonatal brain following birth asphyxia.

Hepatocellular carcinoma (HCC) remains a lethal malignancy with limited therapeutic options. While Poly (ADP-ribose) polymerase inhibitors (PARPi) exploit synthetic lethality in tumors with DNA repair defects, their clinical utility in HCC is hindered by the low prevalence of canonical repair gene mutations and the enhancing DNA repair capacity. Through proteomic analysis of two independent cohorts (n=260), we identified the THO complex component THOC2 as a master regulator of DNA damage response (DDR) via mRNA nuclear export control. Clinically, THOC2 overexpression predicted poor survival (HR=2.68-6.84, P<0.001) and correlated with enhanced DDR gene expression. Mechanistically, THOC2 chaperones mRNA nuclear export of DDR effectors (MDC1, PRKDC, MSH6) and proliferation drivers (TOP2A), thereby establishing a dual pro-repair/pro-growth program. Targeting this vulnerability, THOC2 knockdown induced synthetic lethality with PARPi, reducing Olaparib IC50 by up to 61% and suppressing tumor growth by 76% (P<0.001). Our study illuminates mRNA transport as a druggable DDR modulator and establishes THOC2 as both a prognostic biomarker and a therapeutic target to overcome PARPi resistance in HCC. This work pioneers a strategy to expand synthetic lethality beyond genetic defects by targeting post-transcriptional regulation.

Aberrant neuronal activity is an early pathological feature of numerous neurodegenerative disorders, including tauopathy, and is thought to play a role in disease progression. However, the mechanism underlying abnormal neuronal activity remains elusive. Here, we reveal a relationship between DNA double-strand break (DSB)/p53 pathway activation and aberrant neuronal activity. Activating p53 as part of the DNA damage response via DSB induction, or by preventing MDM2-mediated p53 degradation, causes aberrant activity in both mouse and human neurons. p53 activation induces the expression of genes regulating synaptic transmission, and p53-responsive gene upregulation is overrepresented in postmortem human Alzheimers disease neurons burdened with neurofibrillary tangles (NFTs). Using a human iPSC-based cerebral organoid model of frontotemporal dementia that exhibits relevant pathologies including elevated DSBs, aberrant neuronal activity, and NFTs, we show that inhibiting p53 transcriptional activity with a small molecule ameliorates aberrant calcium fluctuations in neurons. Together, our findings highlight p53 inhibition as a novel therapeutic strategy to counter aberrant neuronal activity in neurodegenerative diseases characterized by tauopathy.

Polyendocrine metabolic ovarian syndrome (PMOS), previously called polycystic ovary syndrome (PCOS) - the most common reproductive endocrinopathy in women of reproductive age, is frequently associated with chronic low-grade inflammation and immune dysregulation. Beyond hyperandrogenism and ovulatory dysfunction, women with PMOS exhibit reduced regulatory T cell (Treg) levels and impaired STAT5 phosphorylation. This study investigates the molecular basis of the defective STAT5 signalling in PMOS. No significant difference in plasma IL2 levels is observed in PMOS women versus normal subjects. Analysis of 102 PMOS patients and 102 controls reveals significantly decreased JAK2 expression alongside increased expression and activity of the phosphatases PTP1B (Protein Tyrosine Phosphatase 1B), TCPTP (T cell Protein Tyrosine Phosphatase), and DUSP4 (Dual Specificity Protein Phosphatase), in leukocytes of PMOS women. In isolated Tregs, only PTP1B and DUSP4 were significantly upregulated. DUSP4 expression positively correlates with serum testosterone and luteinizing hormone levels, linking hormonal imbalance with immune defects. Functional experiments show that silencing PTP1B and DUSP4 enhances IL2-induced Treg generation. Our collective findings identify phosphatase-mediated inhibition of STAT5 signalling as a key mechanism underlying Treg deficiency in PMOS and highlight PTP1B and DUSP4 as potential therapeutic targets to restore immune tolerance and improve reproductive outcomes.

In early intestinal carcinogenesis, adenoma formation is commonly initiated by loss-of-function mutations in a tumor suppressor that lead to oncoprotein gain-of-function, like in the tumor suppressor-oncoprotein pair APC-{beta}-catenin. Small intestinal organoids provide an in vitro system to study consequences of such mutations on tissue organization. However, conventional genetic manipulations do not allow precise control over the onset and duration of oncoprotein activity to study their influence on tissue transformation. Furthermore, homogenous tissues of clonal genetic models do not readily capture cellular interaction among mutated and neighboring wildtype tissue during early transformation. To mimic oncogenic activation of {beta}-catenin, we established a chemical-(opto)genetic approach to gain bio-orthogonal acute, spatial and temporal control over {beta}-catenin oncoprotein stability and relate oncoprotein levels to morphological development of mouse small intestinal organoids. We identified aberrant phenotypes that result from bio-orthogonally induced oncoprotein activity but persist even after oncoprotein depletion. Furthermore, local activation of oncomimetic {beta}-catenin activity within the stem cell niche leads to aberrant differentiation during homeorhesis and homeostasis, recapitulating early events of tissue transformation.

Cas9-based tools enable the introduction of genetic lesions to investigate DNA repair outcomes and edit the genome at disease-relevant loci. DNA double-strand breaks (DSBs) induced by CRISPR/Cas9 result in frequent aneuploidy and large deletions, revealing a repair deficiency in early human embryos and limiting the clinical application of this technology. Here we evaluated the DNA repair outcomes of DNA nicks and mismatches introduced using base editors in human embryos at two targets, PCSK9 and HBG. Editing was efficient and, unlike Cas9-induced DSBs, did not result in either chromosomal abnormalities or large deletions. Small insertions or deletions after base editing were rare, and off-target activity was dependent on the guide RNA. Delivering the base editor as a protein at fertilization or at the pronuclear stage allowed normal development to the blastocyst stage and the derivation of edited stem cell lines. In stark contrast, introduction of the editor as RNA resulted in early embryo arrest. Our results demonstrated that, unlike DSBs, DNA nicks and mismatches are efficiently repaired in human embryos, allowing specific on-target changes without genotoxic consequences.

Guillain-Barre syndrome is an acute immune-mediated polyradiculoneuropathy with heterogeneous outcomes and limited molecular biomarkers for diagnosis, disease monitoring, and prognosis. To elucidate the circulating proteomic profile of this disorder and identify candidate biomarkers associated with disease activity and recovery, we measured over 6,500 proteins using an aptamer-based proteomic platform. We analysed paired, longitudinal sera from 20 patients at disease onset and one-year follow-up, alongside 15 healthy controls. Unbiased differential protein abundance and gene-set enrichment analyses were performed. Candidate proteins were validated using conventional immunoassays in a cohort including healthy and disease controls. We identified 39 differentially abundant proteins between the acute and recovery phases and 248 proteins altered in acute Guillain-Barre syndrome compared to controls. The acute phase was characterised by a marked enrichment in systemic immune cascades and muscle sarcomere proteins, alongside a significant depletion of axonal adhesion molecules. Serum amyloid A1 (SAA1) emerged as the most strongly increased protein in the acute phase. Validation through independent immunoassays confirmed robust serum amyloid A elevations at disease onset relative to the one-year recovery phase, healthy controls, and relevant post-infectious and neuromuscular disease controls (acute disseminated encephalomyelitis and myasthenia gravis), underscoring a peripheral nerve-specific inflammatory response. Furthermore, unexpected elevations of cardiac troponin T (cTnT) were observed at disease onset. Clinical validation using high-sensitivity assays demonstrated that cTnT exceeded the diagnostic 99th percentile upper reference limit in 25.5% of acute Guillain-Barre syndrome patients. A similarly high frequency of elevation in the myasthenia gravis disease control group (42.1%) suggests these increases predominantly reflect neuromuscular damage rather than myocardial injury. Finally, Mendelian randomisation provided causal genetic evidence linking specific systemic proteins to disease susceptibility, identifying robust roles for SERPING1 (plasma protease C1 inhibitor), CNDP1 (an antioxidant protein), and CRISPLD2 (a lipopolysaccharide-binding protein that regulates endotoxin function). Together, this comprehensive proteomic characterisation reveals distinct, stage-specific molecular signatures in Guillain-Barre syndrome. Importantly, it suggests SAA1 as a robust marker of acute peripheral nerve inflammation and challenges the conventional interpretation of elevated cTnT in severe neuropathies and neuromuscular disorders. Furthermore, this work provides a novel dataset to explore future targeted therapeutic development in Guillain-Barre syndrome.

Polycystic ovary syndrome (PCOS) is linked to adverse pregnancy outcomes and increased cardiometabolic risk in offspring, yet the placental mechanisms underlying these risks remain poorly understood. Metformin is prescribed during PCOS pregnancies despite limited mechanistic justification. Using multi-modal molecular analyses of placentas from healthy controls and women with PCOS randomized to placebo or metformin (PregMet trial), restricted to uncomplicated pregnancies, we characterized direct PCOS associated placental alterations independent of confounding complications. PCOS placentas showed transcriptional downregulation across multiple cell types and shifts in cell type proportions. Specifically, syncytiotrophoblasts exhibited reduced expression activity of growth hormone receptor signaling and glycosaminoglycan biosynthesis. Endothelial cells displayed diminished receptor tyrosine kinase pathway activity, including VEGFC, despite increased cell proportion and hypervascularity. Intercellular communication networks were globally suppressed, including reductions in PDGF signaling from Hofbauer cells to fibroblasts. Notably, metformin did not reverse most PCOS-associated molecular alterations and induced transcriptional changes correlated to birth weight and childhood BMI. These findings indicate that PCOS-associated placental features are driven by cell type specific dysregulation of growth factor, angiogenic signaling pathways that are largely unresponsive to metformin. This underscores the need to develop mechanism based, placenta targeted therapeutic alternatives for future pregnancy management.

Despite suppressive antiretroviral therapy (ART), HIV persists in the central nervous system (CNS) and contributes to HIV-associated neurocognitive disorder (HAND), but cell type-specific effects remain poorly defined. Using fluorescence-activated nuclei sorting of postmortem brain tissue of aviremic and viremic deceased people with HIV (DPWH) and HIV-negative individuals, we quantified the size of the HIV CNS reservoir and transcriptional alterations. Microglia were identified as the dominant CNS reservoir, harboring 103-10 HIV DNA copies per million cells by ddPCR-LTR assay in both aviremic and viremic DPWH. Bulk RNA-sequencing revealed immune pathway upregulation specifically in microglia, and downregulation of synaptic and homeostatic pathways across cell-types in viremic compared to aviremic individuals. ART partially mitigated microglial transcriptional dysregulation, but transcriptional profiles did not restore profiles to HIV-negative levels. Notably, persistent microglial infection was associated with transcriptional changes in other cell-types, underscoring microglia as a key therapeutical target for CNS-directed HIV cure strategies.

Lethal congenital contracture syndrome 1 (LCCS1) is a neurodevelopmental disorder caused by GLE1 c.432-10A>G variant and presenting fetal akinesia, defects in anterior horn spinal cord, skin, skull, and skeletal muscle development. The uniform prenatal lethality of LCCS1 limits access to patient material, thereby hindering mechanistic studies in physiologically relevant models. To overcome this, human embryonic stem cells (hESCs) carrying the LCCS1 variant, patient-derived fetal fibroblasts, and transcriptomic and proteomic profiling were utilized to examine early GLE1 dysfunction in human cells and tissues. Across LCCS1 cell types, reduced global transcription and translation were observed, while nucleocytoplasmic poly(A)+ RNA distribution was unchanged. Despite its context-dependent effects on proliferation, LCCS1 variant altered mRNA decay kinetics and increased stress granule formation in differentiated cells. LCCS1 hESCs retained core pluripotency but reduced choline acetyltransferase and {beta} tubulin III levels, together with increased neurofilament inclusion incidence, indicate functional immaturity in differentiated spinal motor neurons. Differentiation of LCCS1 hESC-derived gastruloids uncovered broad perturbations in neuromuscular and neural crest derivative development, results which were supported by phenotypes detected in ectodermal organoids and fetal LCCS1 tissue. These findings provide new mechanistic insight into LCCS1 pathogenesis and establish a robust human model framework for studying neurodevelopmental disorders.

Glioblastoma is a highly aggressive brain tumour with poor prognosis, whose aetiology, progression, and therapeutic resistance remain incompletely understood. While the microbiota-gut-brain axis has emerged as a key regulator of neurological disorders, its role in glioblastoma biology and treatment response is still largely unexplored. Using a clinically relevant immunocompetent murine model combining glioblastoma stem cell implantation, dextran sodium sulfate-induced gut inflammation, and a full Stupp-like therapeutic protocol, we investigated bidirectional gut-brain communication in glioblastoma. Tumour growth and recurrence were monitored by bioluminescence imaging, tumour transcriptomic profiles were analysed by RNA sequencing, and brain and colon tissues were subjected to histological and molecular analyses. Gut microbiota composition was assessed by 16S rRNA sequencing, while systemic metabolites and cytokines were quantified in plasma. Cross-compartment association bioinformatic analyses were performed to correlate multi-organ readouts. Gut inflammation enhanced glioblastoma growth and promoted tumour recurrence following therapy. Tumour progression was associated with increased infiltration of immunosuppressive macrophages, whereas recurrence correlated with elevated oxidative DNA damage. Remarkably, glioblastoma exerted systemic immunomodulatory effects, attenuating intestinal and systemic inflammatory responses, and induced profound remodelling of gut microbiota composition and predicted metabolic function, including enrichment of Akkermansia and depletion of Lactobacillus. Systemic metabolic profiling was investigated as a route of communication within the gut-brain axis and revealed adaptations in DSS-treated mice associated with tumour burden and therapeutic response. Multi-compartment correlation and multivariable association analyses identified specific bacterial genera and circulating metabolites associated with tumour volume, intestinal inflammation, and genomic instability. These findings uncover a dynamic, bidirectional microbiota-gut-brain axis in glioblastoma and identify intestinal inflammation as a critical determinant of tumour progression and therapeutic outcome. Targeting gut disturbances and microbiota-associated metabolic pathways may represent novel strategies to modulate glioblastoma aggressiveness and treatment response.

Pathogenic variants in ATP13A2, which encodes an endolysosomal polyamine exporter, cause Kufor-Rakeb syndrome and are associated with early-onset parkinsonism and related neurodegenerative disorders, however, the mechanisms by which ATP13A2 dysfunction drives disease remain incompletely defined. In Atp13a2 knockout mice, we identified an early, transient reduction in brain polyamines that precedes overt gliosis and behavioural abnormalities. Pharmacological polyamine depletion exacerbates phenotypes, whereas oral supplementation of spermidine, but not spermine, rescues parkinsonian symptoms establishing metabolic polyamine deficiency as a pathogenic driver. Mechanistically, spermidine counteracts microglia lysosomal dysfunction in the brain and exerts mitochondrial antioxidant and anti-inflammatory effects in primary mouse microglia, thereby improving neuronal integrity. In the absence of Atp13a2, microglial spermidine import relies on the related polyamine transporter Atp13a3. Importantly, these findings translate to human systems, whereby spermidine attenuates inflammation in ATP13A2-deficient human differentiated microglia, while postmortem ATP13A2-deficient brain analysis confirms increased microglia reactivity. Spermidine also rescues motor deficits and dopaminergic neuron loss in ATP13A2-deficient Drosophila and other fly parkinsonism models. Together, these findings identify early polyamine dysregulation as a mechanistic contributor to ATP13A2-associated parkinsonism and nominate spermidine supplementation as a potential therapeutic strategy for ATP13A2-driven pathology and possibly a broader range of parkinsonian sub-types.

Pathogenic variants in ATAD3A cause a spectrum of multisystem disorders, with a recurrent dominant-negative variant (c.1582C>T; p.Arg528Trp) associated with neurodevelopmental disease. Given the tolerance of ATAD3A to heterozygous loss of function variants, allele-specific transcript reduction represents a promising therapeutic strategy. We designed and optimized allele-specific antisense oligonucleotides (ASOs) targeting the c.1582C>T transcript and evaluated their efficacy and specificity in affected fibroblasts using allele-specific primers and amplicon-based next generation sequencing. Therapeutic potential was further assessed in vivo in zebrafish embryos expressing human wild-type or mutant ATAD3A transcripts. An optimized gapmer ASO selectively reduced mutant ATAD3A transcripts while relatively sparing the wild-type allele. In addition to RNase H-mediated degradation, the ASO induced exon skipping, leading to degradation of the aberrant transcript without production of a truncated protein. In zebrafish, expression of mutant human ATAD3A in embryos caused developmental abnormalities including reduced eye size, which were robustly rescued by co-injection of the optimized ASO. Our findings provide proof of concept for allele-targeted ASO therapy for dominant-negative ATAD3A variants. This work highlights the therapeutic potential of ASOs for rare dominant disorders involving genes tolerant to heterozygous loss-of-function, and establishes zebrafish as a versatile platform for in vivo ASO optimization.

Herpes Simplex virus type 1 (HSV-1) is a highly prevalent neurotropic virus from the alphaherpesviruses family. In recent years, a growing body of research has focused on the potential role of HSV-1 infections and recurrent reactivations in the pathophysiology of Alzheimers disease (AD). In particular, it has been hypothesized that HSV-1 could initiate or amplify the formation of neuropathological lesions characteristic of AD. To explore further this hypothesis, we adopted an integrated approach aiming at deciphering the impact of HSV-1 infection on AD molecular markers (A{beta} and Tau pathologies) and combining experimental animal models of in vivo infection, postmortem neuropathological analysis of AD brains, as well as in-vivo clinical analysis in AD patients. In animal models of peripheral (labial) infection with HSV-1 virus, we analyzed viral dissemination from peripheral tissues to the CNS, and the associated neuropathological consequences. Histological and molecular analyses revealed the occurrence of viral material (RNA, proteins) in the brainstem, the primary site of viral neuroinvasion, and in more anterior regions of the brain. Viral signatures were accompanied by early abnormal deposits of A{beta} peptides and accumulation of phosphoTau (pTau) proteins in various brain areas. Neuropathological examination of AD/control participants also underlined the presence of HSV-1 DNA in the human brainstem (pons) that was always associated with local A{beta}/Tau aggregates. Finally, in AD patients, associations were found between HSV-1 seropositivity and neuropathological lesion burden (region-specific Tau and A{beta} deposition detected by neuroimaging). Taken together, these data provide new evidence in favor of the involvement of HSV-1 in the pathophysiology of AD, stressing a possible causal link between HSV-1 infection, neuroinvasion and AD neuropathological hallmarks (A{beta} lesions and tauopathy).