EMBO Molecular Medicine

Inflammatory bowel disease (IBD) is a heterogeneous chronic disease driven by dysregulated mucosal immunity and impaired epithelial barrier function. Although biologics have improved disease management, they are frequently associated with systemic immunosuppression and adverse effects, highlighting the need for localized therapeutic strategies that both control inflammation and promote tissue repair. Here, we developed a protein bispecific termed 7A2-IgG4-IL22, composed of a human IgG4-Fc domain displaying an antagonistic anti-human MAdCAM-1 single chain (sc)-Fv and a human interleukin (IL-)22. The anti-MAdCAM-1 scFv retained the functional activity of the parental monoclonal antibody, inhibiting T cell activation, expansion and differentiation from naive precursors. Blockade of the MAdCAM-1 signaling axis also reduced production of pro-inflammatory cytokines relevant to IBD pathogenesis, including IFN{gamma} and TNF. On the epithelial side, the IL-22 cargo induces robust signaling in epithelial cells, promoting the expression of IL-22 response genes associated with antimicrobial defense, mucosal homeostasis, as well as IL-10 and CXCL1 expression. This effect contributes to immune cell trafficking to the intestinal mucosa. Together, this bispecific provides a localized dual-mechanism strategy for restoring intestinal immune homeostasis.

Biallelic variants in HPDL cause a severe neurological disorder in childhood, but the mechanisms linking early developmental abnormalities to later cortical degeneration remain unclear. Here, using long-term iPSC-derived human cortical cultures derived from four patients, we investigated the late consequences of HPDL deficiency through quantitative immunofluorescence and bulk RNA-seq. We found that HPDL-deficient cortical cultures undergo progressive synaptic impairment, with marked loss of PSD95-positive postsynaptic puncta despite largely preserved general neuronal maturation markers. This phenotype is accompanied by a profound reduction in astrocytes and oligodendrocytes, together with increased neuronal apoptosis and transcriptional dysregulation of genes linked to extracellular matrix organization, cellular stress, and neurodegeneration. Unexpectedly, late-stage mutant cultures also show reactivation of early developmental programs, including aberrant expression of NEUROD4 and other proneural regulators, suggesting instability of cell identity during cortical maturation. Together, these findings support a model in which HPDL deficiency first perturbs cortical developmental timing and later drives collapse of the neuro-glial unit, linking premature neurogenesis to synaptic failure, glial loss, and progressive neurodegeneration.

Mechanical circulatory support essential for managing severe heart failure frequently triggers bleeding complications, driven by shear stress-induced over-proteolysis of von Willebrand factor (VWF) by ADAMTS13. Inhibiting ADAMTS13 presents a rationale to treat this condition, known as acquired von Willebrand syndrome (AVWS). However, conventional therapeutic strategies remain limited due to the risk of triggering thrombotic thrombocytopenic purpura. Here we show that HA10, a humanized anti-ADAMTS13 antibody, preserves a residual level of ADAMTS13 activity above the thrombosis-associated threshold. Multimodal structural and biophysical analyses--including NMR, SAXS, and SANS--revealed that HA10 bound to the disintegrin-like domain of ADAMTS13, dynamically competing with VWF while leaving 10- 20% residual enzymatic activity. The therapeutic efficacy and safety of HA10 were verified in non-human primate models of AVWS. Our findings establish a novel paradigm of enzymatic calibration rather than complete blockade, offering a mechanistically targeted and safe therapeutic approach for cardiovascular bleeding.

NOTCH3 is a transmembrane receptor highly expressed in vascular mural cells where it contributes to blood vessel formation and homeostasis. NOTCH3 expression declines in the vasculature with aging, and dysregulated NOTCH3 signalling is implicated in pulmonary arterial hypertension, cancer progression and CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy). RNA-based approaches targeting NOTCH3 are emerging as potential therapeutic strategies, however, the consequences of NOTCH3 suppression in mature vascular smooth muscle cells (VSMCs) remain incompletely understood. Here, we investigated the molecular and functional effects of siRNA-mediated NOTCH3 knockdown in human aortic smooth muscle cells. Transfection with NOTCH3-targeting siRNA efficiently suppressed NOTCH3 transcript and protein levels. Quantitative proteomics revealed remodelling of extracellular matrix (ECM), cytoskeletal and metabolic pathways, with enrichment of collagen biosynthesis and inhibition of glycolytic signalling. Specifically, NOTCH3 knockdown increased ECM components, including COL3A1, elevated F-actin, and upregulated the actin regulator, CTTN. In parallel, glycolytic capacity was reduced, accompanied by decreased expression of the glycolytic enzyme ENO2. Despite reduced VEGFA and alteration in angiogenic signalling proteins, endothelial network formation in co-cultures, as well as VSMC proliferation and migration remained unaffected. Finally, NOTCH3 interactome analysis revealed key collagen and actin-regulating proteins. These findings identify NOTCH3 as an important regulator of ECM homeostasis, cytoskeletal organisation, and glycolytic metabolism. The preservation of primary cellular functions despite molecular remodelling highlights the adaptive capacity of VSMCs. These findings demonstrate that therapeutic modulation of NOTCH3 may alter vascular cell biology which warrants consideration during development of RNA-based therapeutics for CADASIL and other NOTCH3-associated diseases.

Hereditary spastic paraplegia type 7 (SPG7) is a neurodegenerative disorder characterized by progressive motor impairment and cerebellar dysfunction. Mutations in the SPG7 gene, encoding the mitochondrial metalloprotease paraplegin, disrupt mitochondrial homeostasis and lead to neuronal vulnerability and deficits in motor coordination. Recent studies have identified defective flickering of the mitochondrial permeability transition pore (mPTP) in SPG7 models, suggesting that altered pore dynamics may represent a functional biomarker of mitochondrial dysfunction. Here, we investigated whether pharmacological modulation of mPTP activity could improve mitochondrial function and motor performance in SPG7 models. Mitochondrial flickering was assessed in vitro, while motor behavior was evaluated in vivo following chronic treatment with berberine, a natural isoquinoline alkaloid known to modulate mitochondrial bioenergetics. Spg7-/- mice and age-matched Spg7+/ littermate controls received daily oral berberine administration for several weeks, and motor coordination was assessed using the accelerating rotarod test. Untreated Spg7-/- mice exhibited reduced rotarod performance compared with controls, indicating impaired motor coordination. Berberine treatment significantly improved motor performance in pre-symptomatic mutant mice. These findings indicate that pharmacological modulation of mitochondrial permeability transition pore dynamics can ameliorate motor dysfunction associated with SPG7 deficiency and highlight mPTP flickering as a functional readout of mitochondrial health.

Hereditary hemorrhagic telangiectasia (HHT) is a rare vascular disorder caused by pathogenic variants in members of the BMP9/ALK1 signaling hub. In the present study we show that, regardless of whether the alterations are caused by reduced BMP9/ALK1 signaling (pathogenic variants in the ENG or ALK1 genes) or by overactivation of this pathway (such as the SMAD6 pathogenic variants), all are associated with increased endothelial cell (EC) proliferation and high levels of ERK MAPK activation in patient biopsies. We reproduced this phenotype in vitro in ECs lacking SMAD6 or after SMAD1 knockdown using siRNA. Loss of SMAD6 leads to dysregulation of the Notch pathway, with downregulation of phosphatases and consequent overstimulation of ERK. In normal ECs, BMP9 and Notch signaling inhibit ERK activity by upregulating PPP1R3C, a regulatory subunit of the PP1 phosphatase. Notably, BMP9-mediated inhibition of ERK is abolished when cells are transfected with siRNA targeting PPP1R3C. ERK hyperactivation was also observed in an HHT2 mouse model (ALK1-2loxP;Cdh5-CreERT2). Loss of both ALK1 alleles in adult mice leads to vascular failure and hemorrhages in the lung and intestine; these injuries are significantly reduced by treatment with the MEK/ERK inhibitor selumetinib. Overall, our work identifies a key role for ERK activation involved in HHT pathogenesis, suggesting that ERK inhibition may represent a promising therapeutic strategy for these patients. Translational PerspectiveHereditary hemorrhagic telangiectasia (HHTs) is a rare vascular disorder caused by mutations in members of the BMP9/ALK1 signaling hub. In the present study we show that all different forms of HHTs are associated with increased endothelial cell (EC) proliferation, which correlates with high levels of ERK activation in patient biopsies. ERK hyperactivation is also observed in an HHT2 mouse model in which loss of both ALK1 alleles in adult mice leads to vascular failure and hemorrhages in the lung and intestine. These injuries are significantly reduced by treatment with the MEK/ERK inhibitor selumetinib. Overall, our work identifies a key role for ERK activation in HHT pathogenesis, suggesting that ERK/MEK inhibitors may represent a promising therapeutic strategy for these patients.

Hirschsprung disease (HSCR) is a congenital neurodevelopmental disorder characterized by segmental aganglionosis due to impaired developmental processes of enteric neural crest cells (NCCs). Despite being the leading genetic cause of functional intestinal obstruction in early childhood, HSCR represents a paradigmatic challenge in precision medicine: its multifactorial etiology, complex gene-environment interactions and limited resolution of single-modality analyses have long hindered mechanistic understanding and therapeutic translation. Here, we applied an integrative multi-omics approach combining genetic, phenotypic, epigenomic and transcriptomic analyses of matched ganglionic and aganglionic formalin-fixed paraffin-embedded (FFPE) patient tissues, complemented by patient-specific in vitro models. Beyond established genetic contributors, our integrative approach reveals novel regulatory pathways predominantly affecting enteric NCC differentiation, with convergent evidence pointing to epigenetic dysregulation as a primary disease mechanism. Notably, we identified over 1,300 differentially methylated positions between ganglionic and aganglionic FFPE samples, with HAND2 emerging as a key candidate due to multiple hypermethylated sites and consistently reduced expression levels in aganglionic tissues and in vitro models, suggesting a potential role in HSCR pathophysiology. We propose that our multi-omics approach offers a powerful and comprehensive framework for dissecting disease mechanisms. Beyond advancing biological understanding, this strategy holds promise for paving the way for molecularly informed patient stratification and supporting the development of personalized treatment and postoperative management strategies.

Mutations in the VPS45 gene are associated with a rare form of severe congenital neutropenia (SCN5), a life-threatening inherited error of immunity. We developed and characterized a novel mouse model of SCN5 by CRISPR/Cas9-mediated knock-in of pathogenic VPS45 E238K and T224N mutations. Both Vps45 mutations led to decreased protein expression in bone marrow cells. In vivo phenotyping demonstrated a non-Mendelian genetic distribution with reduced numbers of knock-in homozygotes Vps45E238K. Vps45E238K knock-in homozygous mice showed reduced body weight, reduced body condition with age, and increased mortality. As in human SCN5, Vps45E238K knock-in homozygotes demonstrated neutropenia and lymphopenia. Functionally, Vps45E238K knock-in homozygote neutrophils exhibited increased lipopolysaccharide-induced apoptosis and decreased peroxide production, phagocytic capacity and in vivo cell migration, phenocopying the functional defects reported in patients. Vps45T224N knock-in homozygous mice showed a milder phenotype or no abnormalities. In conclusion, this mouse model phenocopies, in part, human SCN5. It provides a novel platform for future studies of the pathophysiology of defects in neutrophil number and function in human SCN5, potential therapies for the disease, and the biochemistry and cell biology of VPS45. Summary statementWe report a mouse model of severe congenital neutropenia due to VPS45 missense mutations. It represents the first animal model of human neutropenia due to a defect in intracellular trafficking.

Unconventional protein secretion mediated by gasdermin D (GSDMD) pores is essential for the release of pro-inflammatory cytokines such as interleukin-1{beta} (IL-1{beta}), a major driver of many inflammatory pathologies. Despite extensive investigation over the years, discovery of IL-1{beta} secretion modulators has been hindered by the lack of robust, scalable experimental platforms. To date, IL-1{beta} related studies largely rely on primary cells and animal models, suitable for mechanistic studies but not readily scalable for high-throughput applications. Here, we engineered a CRISPR-based reporter cell line that allows quantitative monitoring of endogenous IL-1{beta} secretion while preserving the physiologically relevant inflammasome signaling. This platform faithfully recapitulated the response of primary macrophages to pathogen-associated molecular pattern (PAMPs) stimulation and supported the screening of an FDA-approved drug library comprising 1,398 compounds. Form this screen, we identified tolcapone as a potent inhibitor of IL-1{beta} secretion, reducing cytokine release by more than 80% across the screening pipeline. Mechanistically, tolcapone suppressed caspase-1 activation, thereby limiting GSDMD cleavage, pore formation, and the downstream maturation and secretion of IL-1{beta} and IL-18 in vitro. In vivo, tolcapone administration attenuated the acute inflammatory response in a lipopolysaccharide-induced endotoxemia model. Together, these findings establish our reporter platform as a robust tool for discovery of endogenous IL-1{beta} secretion modulators and identify tolcapone as a promising inhibitor of inflammasome-driven immune pathology.

The normal cellular prion protein (PrPC) is an essential substrate in all forms of prion diseases and a receptor for A{beta} oligomers in Alzheimers disease. However, it is not fully understood how cells regulate PrPC levels. Recently, we identified glycogen synthase kinase-3{beta} (GSK-3{beta}) as a potential regulator of PrPC levels in a whole genome knockout screen. Here, we show that both cell surface and total PrPC levels can be reduced either by siRNA-mediated Gsk3b (but not Gsk3a) knockdown or by CRISPR-mediated Gs3b knockout. Whole cell mass spectrometric analysis showed that PrPC was the 60th most significantly reduced protein (out of 7227 total proteins detected) in Gsk3b knockout cells, compared to wild-type cells. Two different GSK-3 inhibitors, laduviglusib (CHIR-99021) and AZD-1080, reduced PrPC levels in mouse CAD5 and human BE(2)-C cells, both in undifferentiated and differentiated states. PrPC levels were similarly reduced by cycloheximide treatment in both Gsk3b knockout and WT cells, indicating that GSK-3{beta} regulates PrPC levels through a post-translational mechanism. Finally, treatment with either laduviglusib or AZD-1080 reduced PrPSc levels in CAD5 cells infected with three different rodent prion strains. Overall, the results reveal that GSK-3{beta} activity controls PrPC levels in living cells, revealing a novel regulatory mechanism and promising therapeutic target.

Cytomegalovirus (CMV) has been implicated in glioblastoma (GBM) progression. Ongoing clinical trials are assessing therapeutic approaches targeting CMV in GBM but to date no new therapy has been approved outside the standard of care. Previous preclinical studies have highlighted the potential of the antiviral drug Cidofovir (CDV) in GBM; however, its clinical use is limited by dose-dependent nephrotoxicity and poor cellular uptake, necessitating high intravenous doses to achieve therapeutic activity. Brincidofovir (BCV), a lipid conjugate of CDV has been developed, which does not induce nephrotoxicity and has significantly greater cellular bioavailability. Here we examined the effects of BCV in a newly established CMV-driven GBM model (SB28) and in patient-derived tumor neurospheres. We show that BCV prolongs survival in vivo and exerts both CMV-dependent and independent antitumor effects. Mechanistically, BCV induces DNA damage and cell cycle dysregulation in GBM cells and inhibits proliferation of patient-derived neurospheres in a dose-dependent manner. These data identify BCV as a dual-action therapeutic that suppresses viral oncomodulation while directly targeting tumor cell viability.

The human heart has a continuous and exceptionally high demand for energy, which is met primarily through mitochondrial oxidative phosphorylation. This dependence places the maintenance and integrity of mitochondrial DNA (mtDNA) for proper mitochondrial function at the center of cardiac health, as mtDNA instability has been shown to cause mitochondrial dysfunction, which can ultimately impair cardiac function leading to cardiomyopathy (CM) and heart failure. However, the contribution of mtDNA instability to cardiac disease remains poorly understood. A growing number of nuclear-encoded proteins have emerged as essential regulators of mtDNA maintenance, organization and segregation. DNA Topoisomerase 3 (TOP3A) is expressed as two isoforms: one is a nuclear-related isoform involved in nuclear genome maintenance while the other localizes to the mitochondria to preserve mtDNA integrity. Recently, individuals bearing biallelic loss-of-function variants in TOP3A manifested phenotypic traits, including CM, typical for mitochondrial dysfunction, supporting a potential mechanistic link between mitochondrial genome instability and TOP3A-related cardiac disease. Here, we investigated the effects of TOP3A deficiency on mtDNA maintenance and stability in the context of TOP3A-associated CM. We employed isogenic wild-type, TOP3A-knockout and BLM-knockout induced pluripotent stem cells (iPSCs) to generate cardiomyocytes (iPSC-CMs) and established a high-throughput, ultra-deep mtDNA sequencing strategy achieving approximately 500,000X coverage to characterize low-frequency mtDNA mutational patterns. Loss of TOP3A triggered an early burst of low-frequency de novo mtDNA single-nucleotide variants during cardiac differentiation, with a striking enrichment within the mitochondrial ribosomal RNA genes, accompanied by a progressive increase in the heteroplasmy of low-frequency mtDNA variants inherited from the common isogenic background. These unique mtDNA signatures were associated with defective mtDNA copy-number expansion and impaired mitochondrial respiration in mature iPSC-CMs. Together, our approach uncovered a previously uncharacterized consequence of TOP3A deficiency and established a link between impaired mtDNA maintenance and mitochondrial dysfunction in TOP3A-associated CM.

The human endogenous retrovirus type W (HERV-W) has been identified as a human-specific neuropathological factor that preferentially affects glial cell types in multiple sclerosis (MS). Recent work using transgenic mice with expression of the HERV-W envelope (ENV) protein unveiled that this endogenous retroviral element disrupts myelin repair and polarizes microglial and astroglial cells towards axon-damaging neurotoxic phenotypes. Moreover, initial clinical trials using Temelimab, a neutralizing antibody targeting the HERV-W ENV protein, have provided circumstantial evidence that ENV exerts anti-regenerative and neurodegenerative effects in MS patients. Aligning these observations, it was therefore concluded that HERV-W represents an important factor contributing to disease progression independent of relapse activity (PIRA). Building on these findings, we here applied a neutralizing anti-ENV antibody in a non-inflammatory demyelination mouse model to directly evaluate its potential to mitigate neurodegeneration and ameliorate remyelination. In transgenic mice with human-specific expression of the HERV-W ENV protein, repetitive intraperitoneal anti-ENV antibody injections resulted in accelerated oligodendroglial differentiation, enhanced remyelination, axonal protection, and reduced neurofilament light chain leakage in the serum. Neurotoxic microglial traits were also reduced, while homeostatic parameters were stabilized. As astroglial cells underwent a similar shift, inducing regenerative traits at the expense of toxic parameters, anti-ENV application overall generated a less hostile cellular environment. This study provides direct evidence of the capacity of HERV-W neutralizing antibodies to access the central nervous system and to ameliorate damage conferred by this viral entity previously associated with smouldering disease processes. Significance StatementAlthough neurodegeneration is a hallmark of multiple sclerosis (MS), its underlying mechanisms are poorly understood. Clinically, it manifests as smouldering MS or progression without relapse activity (PIRA). This is the primary factor leading to the accumulation of clinical disability and is currently untreatable. This study provides the first direct evidence that antibodies directed against the HERV-W ENV protein can attenuate the activity of neurodegeneration-promoting glial cells in vivo. Our data validates neutralization of this endogenous retroviral element as a promising therapeutic approach particularly relevant to the chronic form of MS.

Although effective antiretroviral therapy (ART) has substantially reduced the severity of human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND), the condition remains highly prevalent. Understanding HAND has been a challenge due to the lack of small animal models capable of supporting productive HIV infection in the brain. Recent advances in humanized mouse models with engrafted human glial cells now enable systemic HIV infection that extends to the central nervous system, offering a powerful platform to study HAND pathogenesis. In this study, we investigated behavioral alterations and neuropathological changes associated with HIV infection. Using home-cage monitoring, we observed that HIV-infected mice exhibited reduced feeding efficiency, consuming less food despite increased time spent at the feeder, compared to uninfected controls. Additionally, infected animals displayed disrupted circadian rhythms, with a significant correlation between central nervous system viral load and increased locomotor activity during the light cycle. Neuropathological analyses revealed region-specific vulnerability, with the cortex exhibiting pronounced inflammatory and neurodegenerative changes. These findings were supported by transcriptomic profiling, which demonstrated heightened inflammatory and antiviral gene expression in the cortex associated with differentially expressed genes related to neuropathology and behavior deficits. Together, these results highlight distinct region-specific responses to HIV infection in the brain and establish this humanized mouse model as a valuable tool for elucidating the mechanisms underlying HAND and its associated behavioral deficits.

Scaffold integrity is essential for the activity of proteins that function through protein-protein interactions rather than catalytic output. RAF1 exemplifies this duality: although it is a bona fide kinase and a core component of the MAPK cascade, its tumor-promoting role is largely kinase-independent, relying instead on scaffold-mediated suppression of apoptosis. Genetic Raf1 ablation in KRAS-driven lung adenocarcinoma mouse models induces tumor regression without systemic toxicity, making it an attractive candidate for targeted protein degradation. Chemogenetic systems like the dTAG platform are widely used for preclinical target validation. Here, we generated a dTAG-RAF1 mouse model and showed that pharmacological degradation is efficient and systemically well tolerated, but fails to reproduce the tumor regression observed upon genetic Raf1 ablation. Mechanistically, the N-terminal FKBP12F36V tag (dTAG) perturbs the RAF1 interactome, including scaffold associations with apoptotic regulators, thereby blunting the phenotypic consequences of its degradation. These results establish scaffold integrity as a determinant of chemogenetic system fidelity and argue that degradation tools must be validated at the functional level, not only for target elimination, before assessing their therapeutic relevance.

Huntington's disease is caused by a CAG repeat tract expansion in the huntingtin gene, resulting in production of pathogenic N-terminal huntingtin protein fragments associated with disease pathology. Despite their central role, detection of these fragments has relied on a limited antibody repertoire with reproducibility concerns. Here, we describe the generation and characterization of recombinant rabbit monoclonal antibodies targeting two reciprocal neoepitopes flanking the huntingtin exon 1/exon 2 junction corresponding to amino acids P90 and K91. The P90 antibodies (clones 1B12, 11G2) demonstrate fragment-length-selective recognition of the C-terminal HTTexon1 P90 neoepitope with no detectable binding to full length huntingtin. A side-by-side comparison of the widely used monoclonal antibody MW8 from two different sources revealed measurable lot-to-lot drift in its fragment selectivity, whereas the recombinant P90 antibodies, expressed from a defined, sequenced clone, maintained consistent specificity, addressing this source-dependent variability. Whereas P90-positive fragments can arise through alternative splicing of the HTT1a transcript, generation of the reciprocal K91 N-terminal HTTexon2 neoepitope would require site-specific proteolytic cleavage, a mechanism that has not yet been directly tested for lack of a suitable reagent. The K91 antibody (clone 7G10) binds the N-terminal K91 neoepitope with high affinity and specificity over full length huntingtin and provides, for the first time, a tool capable of directly interrogating whether such cleavage occurs. Neoepitope specificity of these antibodies was orthogonally confirmed by protease digestion (Lys-N and Arg-C) coupled with intact mass spectrometry. As an additional outcome of the immunization and selection strategy, we discovered human-mouse cross-reactive antibodies (clones 27F5, 31C10) targeting the proline-rich domain of huntingtin that will facilitate mouse-human translational studies. All antibodies are recombinant, ensuring long-term reproducibility, and are being made available, along with their sequences, to the research community.

Inhibitor of DNA binding (ID) proteins are key regulators of tumor cell stemness, therapy resistance and pathological angiogenesis in multiple cancer types and other diseases. Here, we characterize the coumarin-derived compound X6632 as a pan-ID inhibitor with dual activity against tumor cells and the tumor-associated microvasculature in a number of human and murine models. X6632 efficiently suppressed ID protein expression, inhibited the proliferation, migration, invasion of melanoma cells, and impaired multiple endothelial cell functions, including proliferation, migration, invasion, tube formation and sprouting in vitro. In back-to-back comparisons, X6632 exhibited an approximately ten-fold higher efficacy compared to the first-generation ID antagonist AGX51. In vivo, X6632 potently reduced pathological (neo)vascularization in established angiogenesis models, including oxygen-induced retinopathy and in Matrigel plug assays. It also significantly decreased blood vessel density in syngeneic melanoma models, delayed tumor growth and, when combined with immune checkpoint blockade, achieved superior tumor control compared with either monotherapy. Moreover, X6632 inhibited clonogenic growth in several breast cancer models, and robustly suppressed the growth of triple negative breast cancer in vivo, both in the highly aggressive 4T1 syngeneic model and in patient-derived xenografts. Collectively, these data establish X6632 as a second-generation, pan-ID protein inhibitor that can simultaneously target malignant cells and the tumor-supporting vasculature, and support the further pre-clinical development of the compound for the treatment of melanoma, breast cancer and potentially additional ID-dependent malignancies, as well as diseases driven by pathological neoangiogenesis.

In young animals, oligodendrocyte progenitor cells (OPCs) undergo robust differentiation, progressing through stages to become pre-myelinating oligodendrocytes (Pre-OL) and ultimately myelinating oligodendrocytes (OLs). However, OPCs from aged animals have reduced differentiation ability. This disrupts myelin maintenance in the central nervous system (CNS), leading to a lack of remyelination following demyelinating injury and impaired adaptive myelination as a mechanism of learning. To uncover novel factors essential for restoring resilience in aged OPCs, we employed a data-driven approach involving the development of a computational pipeline, gSWITCH (accessible at: https://altoslabs.shinyapps.io/gSWITCH/), that allows for capture of precise dynamic gene expression patterns to pinpoint potential switch genes during lineage progression. Using gSWITCH to identify potential switch genes crucial for OPCs, we conducted a comparative analysis of gene expression in OPCs isolated from young and aged animals. This revealed a group of transcription factors with decreased expression in aged OPCs. Further analysis of transcription factor binding site enrichment in OPC switches highlighted Bcl11a, a zinc finger transcription factor that could potentially serve as a master regulator of many switch genes. Ectopic overexpression of Bcl11a in aged OPCs did not enhance their proliferation; however, it significantly enhanced their differentiation into OLs. Overexpression of Bcl11a in aged mice, followed by demyelination injury in spinal cord white matter, significantly increased the differentiation of OPCs into OLs within the injury region compared to control aged mice. Furthermore, we found that Bcl11a is absent in invertebrates and has undergone pervasive purifying selection throughout vertebrate evolution, constraining its amino-acid sequence by eliminating deleterious mutations. Our study shows that reversing the age-related decline of this evolutionarily conserved factor in aged OPCs restores their impaired capacity for differentiation.

Glioblastoma remains highly lethal, with median survival of ~15 months. Resistance to temozolomide is ubiquitous, yet its mechanisms are incompletely understood. Here, we identify the CCL20-CCR6 chemokine axis as a stress-responsive survival pathway limiting therapeutic efficacy. Targeting CCL20-CCR6 in combination with temozolomide and cannabidiol was evaluated using clinical datasets, GBM cell lines, tumor organoids, and a syngeneic CT-2A mouse model integrating proteomic and lipidomic profiling. Low CCL20 expression was associated with improved survival, supporting its prognostic relevance. Across models, TMZ alone or with CBD induced CCL20 expression while exerting limited antitumor activity. Targeted disruption of CCL20-CCR6 signaling using dendrimer-delivered shRNA enhanced therapeutic response in murine models and GBM organoids. Multi-omic analyses revealed that CCL20 inhibition reprograms the tumor microenvironment and induces mitochondrial dysfunction, resulting in elevated reactive oxygen species (ROS) and tumor cell death. This effect was accompanied by accumulation of 17-hydroxydocosahexaenoic acid and activation of oxidative stress-associated cytotoxic pathways. Functional assays confirmed that CCL20 blockade selectively amplifies mitochondrial ROS beyond levels induced by TMZ alone potentiating TMZ efficacy by promoting mitochondrial oxidative stress. Targeting this axis represents a promising strategy to overcome chemoresistance and positions CCL20 as both a prognostic biomarker and a therapeutic vulnerability in GBM.

Cancer stem-like cells (CSCs) not only initiate tumors but also orchestrate angiogenesis through multiple mechanisms, thereby sustaining vascularization and promoting tumor growth. In glioblastoma (GBM; WHO grade IV glioma), the most aggressive adult brain tumor, glioma stem-like cells (GSCs; glioma CSCs) are the main drivers of tumor progression, drug resistance, and recurrence. An interrogated multi-omic secretome analysis identified Wnt-{beta}-catenin signaling-regulated, membrane-localized Seizure Related 6 Homolog (SEZ6) as a patient-derived GSC-specific proangiogenic molecule. Silencing of SEZ6 inhibited the ability of the GSC secretome to induce angiogenic network formation by brain- and lung-derived endothelial cells, but not GSC growth as neurospheres in vitro. SEZ6 silencing also suppressed patient-derived GSC-initiated glioma tumors, resulting in reduced tumor vasculature in an orthotopic mouse model. We also found that SEZ6 induces TGF{beta}-dependent IL-8 expression in endothelial cells to promote angiogenesis. Coimmunoprecipitation and molecular dynamics simulation experiments determined that the Sushi 3 domain of SEZ6 mediates the interaction with TGF{beta} RII to activate the TGF{beta} pathway. Pharmacological inhibition of BACE1 with an in-house-developed small molecule, or blockade of the SEZ6-TGF{beta} RII interaction using a rationally designed peptide, markedly attenuated SEZ6-driven TGF{beta} signaling, and suppressed angiogenesis. Thus, our findings identify SEZ6 as a novel CSC-specific therapeutic target for GBM.