Disease Models & Mechanisms

Colorectal cancer across sub-Saharan Africa presents a growing global health burden, with increasing cases and mortality linked to late diagnosis, limited healthcare access and lack of effective treatments. African patients typically present with aggressive disease marked by distinct genomic signatures, indicating the need for targeted treatment approaches. We integrated genetic modelling, phenotypic scoring, imaging and biochemical analysis to explore how mutations found in individual Nigerian colorectal cancer patients influence drug responsiveness. We used the data from Cancer Genome Atlas to identify mutation profiles specific to Nigerian patients. We then generated ten stable Drosophila melanogaster personalised patient avatar lines designed to model patient genomic profiles. This study focused on three lines; each line included oncogenic RAS plus targeting patient-specific variants. These models exhibited various phenotypes including altered larval size, gut size and reduced survival. Two of the three avatar lines showed improved survival, reduced hindgut proliferation zone expansion and restored redox balance after treatment with regorafenib and trametinib. Mirroring clinical patient responses, we found that response to therapy is dependent on the specific genetic profile of the tumour. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/714433v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@110518aorg.highwire.dtl.DTLVardef@5965a0org.highwire.dtl.DTLVardef@11f16a3org.highwire.dtl.DTLVardef@744a1_HPS_FORMAT_FIGEXP M_FIG C_FIG O_LIAfrican colorectal cancer showed distinct mutation patterns that contribute to tumour heterogeneity. C_LIO_LIPatient-derived Drosophila avatars were engineered using tumour-specific genetic mutations with key features of human colorectal cancer. C_LIO_LITreatment with targeted therapies showed responses patterned by tumour genotype. C_LIO_LIResponse patterns indicated the need for personalised for colorectal cancer therapies among diverse populations. C_LI

Metastatic breast cancer is responsible for around 11,500 deaths a year in the UK. The primary tumour likely plays a major role in priming the distant site for metastasis and crosstalk between primary and metastatic sites may be essential for secondary tumour growth. We have developed a novel in vitro model in which we can further study these interactions; evaluating niche priming and cancer cell conditioning as well as assessing their influence on cell homing and colonisation. In this paper we describe a model that we believe adds to the array of in vitro tools available to study various stages of the metastatic cascade, offering a unique opportunity to assess bidirectional, primary to niche interactions in vitro. We show that proliferation, migration and chemotaxis, and stem cell activity are altered in both cancer cell lines and in lung epithelial cells following linked, fluidic culture. Changes in cell homing and colonisation can be modelled in cell lines and within viable lung tissue explants taken from mice, with breast cancer cells settling and growing within the lung epithelial cells and tissue explants over 7 days. The colonisation/growth of cells injected into the system closely represents that seen following tail vein injection and cancer cells can be seen to settle and grow within the lung epithelial cells.

Spinocerebellar ataxia type 1 (SCA1) is a progressive neurodegenerative disorder caused by polyglutamine expansion in ATXN1, yet the normal physiological roles of ATXN1 and its paralog ATXN1L remain incompletely understood. To define these roles, we generated the first zebrafish knockouts (KOs) of the three ataxin-1 family genes, atxn1a, atxn1b, and atxn1l, using CRISPR/Cas9. These mutants reveal distinct and shared developmental, behavioral, and transcriptomic alterations. All KOs showed reduced early survival and mild larval growth deficits, indicating essential developmental functions. Behavioral assays revealed distinct paralog-specific effects: atxn1a KO larvae exhibited a unique light-dependent locomotor deficit, whereas atxn1b and atxn1l KOs displayed global hypoactivity. Adult behavioral assessment revealed a gradient of phenotypic severity: atxn1a KOs displayed the earliest and most pronounced alterations in vertical tank exploration and the greatest impairment in swim-tunnel performance, followed by atxn1b and then atxn1l mutants. To define molecular mechanisms underlying these phenotypes, we performed RNA-seq at 5 days post-fertilization and identified unique and shared differentially expressed genes across the three KO lines. Shared transcriptomic signatures highlighted suppression of leukotriene-biosynthetic pathways and diminished innate-immune pathways; suggesting that ATXN1-family genes influence neuroimmune signaling during early development. Weighted gene co-expression network analysis identified distinct KO-associated gene modules, including a phototransduction-enriched module strongly correlated with atxn1a KO status, offering a mechanistic link to its light-dependent locomotor phenotype. Together, these findings establish a comprehensive assessment of zebrafish models that reveal both shared core functions and specialized roles of ATXN1-family genes in development, neuroimmune regulation, sensorimotor behavior, and retinal signaling.

Fuchs endothelial corneal dystrophy (FECD) impacts over 300 million individuals worldwide with corneal transplantation as the primary treatment. There is a dire need to establish non-surgical alternatives which are dependent on mouse models. Transcriptional co-activator with PDZ-binding motif (TAZ, encoded by Wwtr1) is a mechanotransducer implicated in maintaining homeostasis of corneal endothelial cells (CEnC). Wwtr1-/- (TAZ KO) mice serve as an animal model for late-onset FECD. We combined single-cell transcriptomics, transmission electron microscopy, and immunofluorescence staining to elucidate the mechanisms driving pathogenesis in young (2-month-old) and geriatric (11-month-old) mice. A progressive stress response was observed in TAZ KOs defined by endoplasmic reticulum (ER) stress, mitochondrial structural and functional abnormalities, and impaired Na+/K+ ATPase localization. These changes were accompanied by an altered expression of genes involved in extracellular matrix (ECM) organization, oxidative phosphorylation, macroautophagy and response to oxidative stress. Additionally, we noted age-related differences in cellular response with young TAZ KO CEnCs upregulating macroautophagy and downregulating ECM organization while geriatric TAZ KO CEnCs downregulated macroautophagy, and ECM organization. Both TAZ KO groups downregulated response to oxidative stress and cell-substrate adhesion. Together, these findings establish a mechanistic link between disrupted mechanotransduction and organelle stress in CEnC degeneration, further elaborating on potential mechanisms driving FECD pathogenesis. This positions TAZ KO mice as a translational platform for evaluating non-surgical therapeutic strategies targeting FECD. Significance statementFuchs endothelial corneal dystrophy (FECD) is a common, age-related cause of vision loss involving a depletion of corneal endothelial cells (CEnC) that necessitates corneal transplantation. Understanding why corneal endothelial cells progressively fail in this disease is essential for developing non-surgical therapies. Using transcriptomics, electron microscopy and immunofluorescence staining, we demonstrate that loss of the mechanotransducer TAZ disrupts cellular homeostasis by inducing endoplasmic reticulum stress, mitochondrial dysfunction and improper extracellular matrix and functional protein organization in CEnCs. By linking altered mechanotransduction to organelle stress and endothelial cell loss, these findings provide insight into fundamental disease mechanisms and identify pathways that may be targeted to preserve corneal endothelial function in FECD.

Well- and dedifferentiated liposarcomas (WDLPS and DDLPS) are characterized by extensive copy- number alterations rather than recurrent gene-inactivating mutations, obscuring the molecular mechanisms that drive disease progression and, critically, the transition from well-differentiated to the more aggressive dedifferentiated tumor states. Despite marked differences in clinical behavior and prognosis, the regulatory events underlying adipocytic lineage destabilization in DDLPS remain poorly understood. Here, we establish an in vivo model of retroperitoneal liposarcoma in Xenopus tropicalis through early embryonic mosaic perturbation of p53 and Rb pathway components. Combined disruption reproducibly induced retroperitoneal WDLPS development, demonstrating that pathway-level deregulation of the MDM2-p53 and CDK4-Rb axes is sufficient to initiate liposarcoma development in vivo. Strikingly, additional perturbation of transcriptional co-activator ep300 in this context resulted in increased tumor dedifferentiation, yielding lesions composed of spatially coexisting well- and dedifferentiated adipocytic states. In contrast, direct targeted disruption of downstream adipogenic regulators recurrently lost in human DDLPS, including cebpa, g0s2, and dgat2, failed to induce dedifferentiation in the same genetic context in vivo. These findings indicate that dedifferentiation cannot be explained by loss of downstream adipocytic effectors alone but instead reflects destabilization of higher-order regulatory programs governing adipocytic identity. Together, these results establish an in vivo model that closely reflects the clinical situation on a pathway level and provides initial mechanistic insight into how adipocytic differentiation may become destabilized during disease progression. This framework offers a foundation for future studies leveraging higher-order and multi-omic approaches to dissect the molecular processes underlying the WDLPS-to-DDLPS transition.

STUDY QUESTIONAre pathogenic variants in Homeodomain-interacting protein kinase (HIPK4) associated with sperm head abnormalities causing male infertility? SUMMARY ANSWERHIPK4 is a novel candidate gene associated with sperm head defects and human male infertility. WHAT IS KNOWN ALREADYNumerous genes causing male infertility due to Multiple Morphological Abnormalities of the sperm flagella (MMAF) have been described but the genetic basis of sperm head defects is less well understood. STUDY DESIGN, SIZE, DURATIONFour infertile brothers displaying varying degrees of quantitatively and/or qualitatively impaired spermatogenesis, their parents, and their fertile brother were included in the study. Further, the Male Reproductive Genomics (MERGE) cohort comprising exome/genome sequencing data of >3,300 men was queried. PARTICIPANTS/MATERIALS, SETTING, METHODSWe performed exome sequencing in all five brothers and their parents. To characterise the sperm phenotype, standard semen analysis, immunofluorescence staining, and transmission-electron microscopy (TEM) were carried out. Further, we evaluated the impact of the HIPK4 variant in cell culture experiments using HEK293T cells. MAIN RESULTS AND THE ROLE OF CHANCEAnalysing the exome data, we could not identify a common genetic cause in all four affected brothers. However, one of the affected brothers was compound heterozygous for two loss-of-function variants in DNAH17 (c.1076_1077dup p.(Lys360*) and c.7752+2T>A p.?) associated with markedly reduced sperm motility and MMAF. The variants pathogenicity was further validated by TEM of flagellar cross-sections revealing an outer dynein arm defect and axonemal disruption. On the contrary, his three infertile brothers were homozygous for the start-loss variant c.1A>G in HIPK4. This gene is expressed during spermiogenesis and is reportedly involved in sperm head shaping in mice. Heterologous expression of (partial) HIPK4 variant cDNA elucidated the alternative use of an in frame start codon located 35 amino acids downstream, resulting in an N-terminally truncated protein p.(Met1_Glu35del). The truncated HIPK4 protein lacks parts of its kinase domain and shows reduced protein stability. In line with published mouse models, all three brothers displayed 100% abnormal sperm head morphology with variable defects. Importantly, one brother affected by HIPK4 variants fathered a child after successful intracytoplasmic sperm injection demonstrating that it is a treatment option for HIPK4-related teratozoospermia. No further men from the MERGE cohort were affected by biallelic HIPK4 variants. Taken together, HIPK4 is an autosomal-recessive candidate gene associated with sperm head defects and male infertility. LARGE SCALE DATAThe reported variants in DNAH17 and HIPK4 were submitted to ClinVar. LIMITATIONS, REASONS FOR CAUTIONIndependent replication is required to assess the phenotypic spectrum and the reproductive outcome associated with biallelic HIPK4 variants and to formally establish the gene-disease relationship for male infertility. WIDER IMPLICATIONS OF THE FINDINGSThis study raises awareness of the significant genetic heterogeneity of male infertility. The described family highlights that distinct genetic causes may underlie a seemingly similar phenotype. Exome sequencing of families is helpful to efficiently disentangle individual causes among affected family members. STUDY FUNDING/COMPETING INTEREST(S)N.N., J.R., H.O., S.L., C.F., and F.T. were supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within the Clinical Research Unit Male Germ Cells (CRU326, project number 329621271). R.T.W., N.N., J.R., H.O., and F.T. were supported by the Federal Ministry of Research, Technology and Space (BMFTR) as part of the project ReproTrack.MS (grant 01GR2303). S.A.K. was supported by the DFG Clinician Scientist programme CareerS Munster (project number 493624047). A.S.G. was supported by the Medical Faculty Munster via an Innovative Medical Research (IMF) grant (GA-122104).

The dy3K/dy3K Lama2-/- mouse is a model for the severe form of LAMA2-related dystrophy and peripheral neuropathy (LAMA2-RD). In the dystrophic mice, a compensating laminin subunit, Lm4, that lacks polymerization and -dystroglycan-binding activity, replaces the missing Lm2 subunit. It was previously found that an 4-laminin can be modified with two small laminin-binding linker proteins, i.e. LNNd{Delta}G2 and miniagrin to facilitate polymerization and -dystroglycan binding respectively, to enable the key missing functions. Adeno-associated virus serotype 9 (AAV9) was used to deliver minigenes coding for the two proteins in dystrophic mice. AAV9-LNNd{Delta}G2 utilized a universal CBh promoter while AAV9-miniagrin utilized either the CBh promoter or muscle-specific SPc5-12 promoter. The phenotype in the dy3K/dy3K mice was evaluated following i.v. postnatal injection with either AAV9 -LNNd{Delta}G2 alone or in combination with AAV9- LNNd{Delta}G2 + AAV9- miniagrin. Double AAV treatment was found to substantially increase survival and ambulation, as well as increase forelimb grip-strength and improve muscle histology. Of note, the sciatic nerve amyelination characteristic of laminin 2-deficiency was prevented. While single treatment with LNNd{Delta}G2 was inferior to double treatment for muscle strength and survival, it corrected the radial sorting deficit equally, revealing that enablement of laminin polymerization is a sufficient requirement for myelination. HighlightsO_LIThe dy3K/dy3K (Lama2-/-) mouse, a model for severe LAMA2-related dystrophy, expresses laminin-411 that is unable to polymerize or bind to -dystroglycan (DG). C_LIO_LILNNd{Delta}G2 and miniagrin are laminin-411-binding proteins that enable polymerization and DG binding. C_LIO_LIAAV9 delivery of genes coding for LNNd{Delta}G2 and miniagrin ameliorated the dystrophic phenotype in muscle and nerve (survival, growth, mobility, and grip-strength, muscle and nerve histopathology). C_LIO_LISciatic nerve amyelination was prevented by LNNd{Delta}G2 alone. C_LI

The ryanodine receptor (RYR) genes encode evolutionarily conserved calcium release channels involved in a wide range of calcium-dependent biological processes. Here we show that the sole Drosophila RYR gene (dRyR) functions in differentiated somatic and cardiac muscle as well as in developing embryonic myotubes. In the larval body wall muscles, dRyR protein localizes at the SR membranes and dRyR knockdown adversely affects muscle contractility, suggesting its conserved role in calcium-triggered E-C coupling. After dRyR attenuation, sarcomere and mitochondrial patterns are severely impaired, showing dRyR involvement in structural muscle properties. However, dRyR is also prominently expressed and functionally required in growing embryonic muscles. dRyR loss of function leads to myotube growth defects and thin myofiber phenotypes, while its overexpression induces myofiber splitting. Given the structural and functional conservation of dRyR, we used Drosophila to test the impact of one human RYR1 variant of unknown significance (VUS). Larvae carrying p.Met4881Ile RYR1 VUS showed impaired mobility and altered structural muscle properties reminiscent of those seen in dRyR knockdown, thus indicating it is likely pathogenic. Overall, we show that Drosophila dRyR plays a conserved role in setting muscle contractility and structural muscle features. Our findings underline the still under-investigated role of dRyR as a promyogenic factor and provide a first example of the impact assessment of a human RYR1 VUS in Drosophila.

Wolfram syndrome is a rare autosomal recessive disorder characterized by antibody-negative early-onset diabetes mellitus, optic atrophy, sensorineural hearing loss, arginine-vasopressin deficiency, and progressive neurodegeneration of the brainstem and cerebellum. It is caused primarily by pathogenic variants in the WFS1 gene, which encodes a transmembrane endoplasmic reticulum-resident protein involved in the unfolded protein response and cellular calcium homeostasis. Although multiple rodent models of Wolfram syndrome have been developed and shown to exhibit visual defects, some studies have reported significant vision loss prior to any detectable axonal degeneration or myelin abnormalities, and the mechanisms underlying these early visual deficits remain poorly understood. Recent in vitro studies have demonstrated altered synaptic contacts and aberrant neurite morphology in WFS1-deficient cerebral organoids and human iPSC-derived neurons, respectively. These findings prompted us to investigate, for the first time in vivo, whether synaptic and dendritic abnormalities occur in the retina of Wfs1 knockout mice. Using confocal microscopy, we examined retinal and optic nerve histology in Wfs1 knockout mice at 4 and 7 months of age. Our analysis reveals progressive synaptic alterations in the inner plexiform layer, driven by early presynaptic compartment failure. These changes represent the earliest detectable phenotype associated with vision loss in this model and precede overt axonal degeneration.

Tumor cells commonly exhibit aerobic glycolysis and produce lactate despite oxygen availability. Lactate dehydrogenase (LDH) catalyzes pyruvate-lactate interconversion and regulates intracellular lactate levels. Endothelial cells also depend on glycolysis for ATP production, which prompted us to investigate LDH in canine hemangiosarcoma (HSA), a malignant endothelial tumor. We inhibited LDH with (R)-GNE-140 or sodium oxamate in two canine HSA cell lines (HU-HSA-2 and HU-HSA-3) and generated HU-HSA-3 clones with knockout of LDHA or LDHB to evaluate the effects of LDH perturbation. (R)-GNE-140 and sodium oxamate suppressed proliferation and reduced global histone lactylation levels in both cell lines. mRNA-sequencing (mRNA-seq) of (R)-GNE-140-treated HU-HSA-2 cells identified cholesterol/lipid metabolism-related gene sets among the top negatively enriched pathways. Representative cholesterol/lipid metabolism genes responded differently depending on cell lines and inhibitors. (R)-GNE-140 decreased these genes in HU-HSA-2 but not HU-HSA-3, whereas sodium oxamate decreased them in HU-HSA-3 with limited effects in HU-HSA-2. In HU-HSA-3, LDHA and LDHB knockout clones decreased SREBP2 expression and reduced the number of lipid droplets. Fluvastatin, a cholesterol metabolism inhibitor, inhibited HSA cell growth in vitro but did not significantly suppress tumor growth in two HSA patient-derived xenograft (PDX) models. In contrast, combined fluvastatin and dipyridamole treatment inhibited proliferation in vitro and tumor growth in PDX models. Collectively, these results suggest a context-dependent association between LDH and cholesterol/lipid metabolism in canine HSA cell lines and provide a rationale for further evaluation of combined cholesterol pathway inhibition.

Dietary restriction (DR) extends lifespan in many animal species. In C. elegans, Eat mutants with pharyngeal defects that impair feeding exhibit reduced growth rate and fertility and are typically long-lived, suggesting a DR effect. We report that Eat mutant longevity is largely or wholly a consequence of suppression of feeding activity-dependent infection of the pharynx by their E. coli food source. eat-2 mutants, widely used as a DR model, were among only 2/8 Eat mutants tested whose longevity were to any degree independent of bacterial infection. Moreover, among Eat mutants, phenotypic indicators of reduced nutrition correlated with one another, yet not with longevity. Thus, eat-2 longevity is partially due to infection resistance rather than DR, and residual, infection-independent longevity could equally reflect DR or some other consequence of their cholinergic signaling defect. We therefore conclude that eat-2 mutants are not at present a trustworthy model for studies of DR.

Robinow Syndrome is a polygenic, rare skeletal disorder characterized by craniofacial and limb defects. The genes involved are in the Wingless-related Integration site-1 (WNT) pathway and DVL1 (Dishevelled 1) is the most commonly affected gene. In all pathogenic variants of DVL1, a frameshift replaces the C terminus with a novel peptide. We tested whether the variant DVL11519{Delta}T was sufficient to alter development in vivo and in vitro in two animal models. We compared phenotypes to wtDVL1 or DVL1 with a stop codon at position 1519. Misexpression of DVL11519{Delta}T in the developing face of chicken embryos with an avian retrovirus, leads to a widening of the frontonasal mass similar to the human facial phenotype and ultimately to inhibition of skeletogenesis that was also verified in primary cultures of frontonasal mass mesenchyme. In luciferase assays carried out in facial mesenchyme, the wtDVL1 activated canonical and JNK PCP WNT signalling however the DVL11519* and the DVL11519{Delta}T variant removed some but not all of the signaling activity. We also determined that there is mislocalization of the protein expressed from DVL11519{Delta}T in the nucleus while the other two constructs were mainly found in the cytoplasm. In complementary Drosophila experiments using a variety of readouts, only the DVL11519{Delta}T variant impacted morphogenesis and signaling. This is the first study to clarify the pathogenesis of Robinow syndrome is due to the novel C-terminus of DVL1 which exerts dominant interference on morphogenesis, skeletogenesis and WNT signaling.

PLA2G6-associated neurodegeneration (PLAN) is a rare, progressive neurological disorder caused by mutations in the PLA2G6 gene, which encodes the calcium-independent phospholipase A2 enzyme essential for phospholipid remodeling and membrane lipid homeostasis through the Lands cycle. Although mitochondrial dysfunction has been implicated in PLAN, the mechanisms linking PLA2G6 loss to mitochondrial degeneration across tissues, age, and sex remain poorly defined. Drosophila melanogaster (fruit flies) contains the human ortholog of the PLA2G6 gene, called iPLA2-VIA, homozygous mutation of which shows neurodegenerative phenotypes, including severely reduced lifespan, loss of locomotory ability, reduced fecundity, and mitochondrial structural and functional impairment at an early age. Thus, we use the Drosophila melanogaster iPLA2-VIA homozygous mutant flies to systematically examine mitochondrial structure, abundance, function, and the altered gene expression of the genes associated with the mitochondrial biogenesis cycle. Transmission electron microscopy revealed mitochondrial ultrastructural abnormalities in the brain, thorax, and ovary of iPLA2-VIA mutant flies, including disrupted cristae, abnormal mitochondrial morphology, and abnormal membrane integrity. Quantitative analysis demonstrated a significant, age-dependent reduction in mitochondrial number across multiple tissues in both sexes. Consistent with these structural defects, mutant flies exhibited reduced ATP production and altered reactive oxygen species (ROS) levels in a tissue-, age-, and sex-specific manner, indicating impaired mitochondrial bioenergetic capacity. At the transcriptional level, loss of function of iPLA2-VIA significantly altered the expression of genes governing mitochondrial biogenesis and dynamics. Key biogenesis regulators, including mTOR and PGC-1, were downregulated in young mutants, while genes involved in mitochondrial fusion and fission (Opa1, Mfn2, Drp1, and Fis1) showed selective, age- and sex-dependent dysregulation. Collectively, our findings demonstrate that iPLA2-VIA is essential for maintaining mitochondrial integrity, abundance, and bioenergetic function. This work establishes a mechanistic framework linking disrupted phospholipid remodeling to mitochondrial degeneration in PLAN. It highlights Drosophila as a powerful model for dissecting age- and sex-dependent mitochondrial pathology in neurodegenerative disease.

Dominant variants in the retinoic acid receptor beta (RARB) gene cause a complex disorder known as RARB-related disorder (RARB-RD), characterized by multiple congenital anomalies, global developmental delay, and dystonia. RARB-RD variants have been classified as either gain-of-function (GOF) or dominant-negative (DN) based on their cell-based transcriptional responses to retinoids. To investigate the mechanisms underlying this disorder, we generated mouse models carrying either the p.R387C or p.L402P RARB-RD variant, previously categorized as GOF and DN, respectively. Homozygous mice for either RARB-RD variant died perinatally with colonic aganglionosis, while heterozygous mice survived and recapitulated several features of RARB-RD. In addition to microphthalmia, both RarbR387C/+and RarbL402P/+ mice exhibited progressive coordination deficits, increased active-phase locomotor activity, and cognitive impairment in the novel object recognition test. In contrast, mice heterozygous for a null allele of Rarb (Rarb+/-) did not display these abnormalities. In the brain, Rarb is predominantly expressed in the two major populations of projection neurons of the striatum recognizable by the expression of dopamine receptors D1R/Drd1 and D2R/Drd2. Marker analysis revealed a reduction in Drd2-expressing neurons without changes in Drd1-expressing neurons in both RARB-RD models. Furthermore, RARB-RD mice showed partial resistance to the cataleptic effects of haloperidol, a D2R-specific antagonist. These behavioral, cellular, and dopaminergic deficits--though not the cognitive impairments--have previously been observed in Rarb-/- mice. To determine whether the in vitro effects of RARB-RD variants correlate with distinct transcriptional signatures in vivo, we compared the striatal transcriptome of RarbR387C/+, RarbL402P/+, Rarb-/- and Rarb+/-mice with their littermate controls. We found that the heterozygous RARB-RD variants and the homozygous null allele affected a large subset of common genes, with putative direct RARB targets predominantly downregulated. Notably, the transcriptional impact of the RARB-RD variants was more profound than that of the null allele, regardless of zygosity. Additionally, transcriptional changes in RARB-RD mice extensively overlapped with those observed in mouse models of Huntingtons disease, suggesting shared mechanisms affecting neuronal survival in the striatum. We conclude that the p.R387C and p.L402P variants similarly compromise striatal integrity and function, likely through a DN mechanism. Progressive emergence of most neurologic deficits highlights a potential therapeutic window. Our results support the development of strategies aimed at silencing RARB-RD alleles.

PTEN (phosphatase and tensin homologue deleted on chromosome ten) is a tumour suppressor, the function of which is impaired in many diverse cancers. It has phosphoinositide lipid phosphatase activity by which it suppresses activation of the oncogenic PI3K signalling network but in vitro also displays activity against protein substrates and is able to auto-dephosphorylate its Thr366 residue. Here we generate germline knock-in mice expressing PTEN-Y138L, a mutant enzyme which selectively lacks protein phosphatase activity and retains lipid phosphatase activity. Homozygous PtenY138L/Y138L mice die in utero before E10.5. Primary MEFs and thymocytes with only a single PtenY138L allele display normal low levels of AKT phosphorylation indicating effective regulation of PI3K signalling by endogenous PTEN-Y138L in vivo. Heterozygous Pten+/Y138L mice have reduced overall survival compared to wild type littermates and develop tumours in multiple organs. Our data imply that in addition to its lipid phosphatase activity, the protein phosphatase activity of PTEN is also required for normal embryonic development and tumour suppression.

Diabetic foot ulcers (DFUs) remain a major clinical challenge as diabetes prevalence rises, emphasizing the need for improved therapeutics and relevant preclinical models. Common rodent wound-healing models poorly recapitulate human skin anatomy and repair. Although porcine skin is comparable to human skin, many studies employ young, healthy pigs that do not reflect typical chronic human wounds. Here, we evaluated wound healing in full-thickness skin wounds in non-diabetic and diabetic Yucatan minipigs. RNA sequencing identified key transcriptional differences in wounds of diabetic versus non-diabetic animals, including pathways linked to increased inflammation and oxidative stress, as well as decreased metabolism and extracellular matrix organization, known hallmarks of DFUs. These findings support this preclinical model as a powerful approach for discovery and therapeutic testing in diabetic wounds and provide a novel data set for further mining of potential gene targets for diabetic wound intervention.

Niemann-Pick disease, type C is an autosomal recessive, fatal, neurodegenerative disorder caused by pathological variants in NPC1 or NPC2. Dysfunction of either NPC1 or NPC2 results in impaired intracellular cholesterol transport and subsequent storage of unesterified cholesterol in endolysosomal compartments. Earlier cell-based studies utilized patient fibroblasts to study this disease; however, neuronal cells allow for investigation of the neurodegenerative aspect of NPC1. Expression of neurogenin in induced pluripotent stem cells leads to the generation of i3Neurons (integrated, isogenic, and inducible), allowing for rapid, synchronized growth of homogenous neurons. In this study, we report the development and characterization of a human iPSC-derived NPC1I1061T/I1061Ti3Neuronal model system. NPC1I1061Tis a missense variant resulting in a misfolded protein targeted for proteasomal degradation in the ER. NPC1I1061T/I1061T i3Neurons phenocopied the cellular pathological features of NPC1 disease including endolysosomal cholesterol accumulation, lysosomal morphological changes, and response to the proteostasis modulator, mo56HC. The NPC1 phenotype was alleviated by 2-hydroxypropyl-{beta}-cyclodextrin treatment, a drug demonstrating efficacy both in vitro and in vivo. This NPC1I1061T/I1061T i3Neuronal cell line can facilitate future high-throughput drug and genomic screens, particularly those aimed at identifying proteostasis regulators that improve the expression/stability of the mutant NPC1 protein.

Sphingomyelin is a critical sphingolipid found in plasma membranes of metazoa that provides structural and communicative functions. Sphingomyelin synthases are key enzymes that generate sphingomyelin but their precise functions in animal development and function are not fully understood. The Caenorhabditis elegans model encodes five sphingomyelin synthases (sms-1-5). Previously, egg-laying and locomotion phenotypes were observed in an sms-1(ok2399) deletion mutant. In this study, we attempted to replicate these findings to enable mechanistic dissection of sphingomyelin function. We indeed found that the sms-1(ok2399) mutant exhibited egg-laying and locomotion defects, however, we were unable to rescue this phenotype. Further, we generated two additional sms-1 deletion mutants (rp398 and rp399) and found that their egg-laying and locomotion behavior is not different to wild-type animals. We suggest that the sms-1(ok2399) contains a background mutation that causes behavioral deficits, and that SMS-1 loss does not overtly affect C. elegans egg-laying or locomotion.

Infertility generates profound psychological and social distress for both women and men, yet mens communicative experiences remain comparatively underexamined. Male infertility (MI) is often shaped by stigma, norms of masculinity, and limited opportunities for emotional disclosure, constraining help-seeking in offline settings. This study investigates how men use anonymous online peer-support spaces to discuss MI by analyzing discussions from the r/maleinfertility subreddit on Reddit. Using natural language processing techniques, we examined 10,769 posts and 80,381 comments published between 2013 and 2025. Analyses assessed sentiment and emotional expression, topic structure, hyperlink networks, and discussions related to diagnostic testing, treatment decision-making, and donor sperm use. Topic modeling revealed a functional differentiation between posts and comments. Original posts primarily focused on clinical sense-making, including interpretation of semen analyses, hormonal testing, and assisted reproduction options. In contrast, comments emphasized emotional validation, experiential knowledge-sharing, and normalization of alternative family-building pathways. Emotional expression varied by discussion topic, with heightened fear and sadness in conversations involving genetic testing, surgical sperm retrieval, and donor sperm. Hyperlink analysis indicated frequent engagement with peer-reviewed medical information, reflecting active evidence-seeking alongside peer exchange. Taken together, findings suggest that anonymous online communities function as critical infrastructures of support for men experiencing infertility, enabling forms of disclosure and vulnerability often constrained in offline contexts. These spaces facilitate interpretation of medical information, collective coping, and decision-making regarding treatment and donor options. The study highlights the role of digital anonymity in mitigating stigma and expanding communicative possibilities for men navigating infertility alongside clinical care.

Familial Episodic Pain Syndrome (FEPS) is a rare inherited disorder characterized by episodes of severe upper-body pain triggered by different stimuli including cold, stress, or fasting. A gain-of-function point mutation (N855S) in the Transient Receptor Potential Ankyrin 1 (TRPA1) ion channel has been identified in affected individuals, altering its biophysical properties, and leading to sustained nociceptive signaling. While TRPA1 is predominantly studied in sensory neurons, recent findings highlight its key modulatory role for Schwann cells in chronic pain. Here, we investigated the cell-specific contributions of mutant TRPA1 (TRPA1*) in FEPS by developing mouse models with TRPA1* selectively expressed in either Schwann cells or sensory neurons, using CRISPR-based and Cre-loxP strategies. Patch-clamp analyses confirmed that TRPA1* exhibits enhanced current responses to agonists compared to wild-type. Through behavioral assays we revealed that TRPA1* expressed in sensory neurons mediates acute nociception, while TRPA1* in Schwann cells drives mechanical allodynia in response to subthreshold doses of TRPA1 agonists and to physiological pain triggers commonly observed in FEPS patients, including fasting, cold exposure, and restraint stress. Pain responses were associated with the increase in reactive oxygen species (ROS) and accumulation of 4-hydroxynonenal (4-HNE) in TRPA1* sciatic nerves and these effects were reduced by a treatment with an antioxidant. We reveal distinct roles of neuronal and non-neuronal TRPA1 in pain and provide novel in vivo models to investigate the mechanisms of chronic pain in FEPS and related channelopathies. Overall, this study offers new insights into the development of targeted therapies for Schwann cell-TRPA1 to relieve pain in affected individuals.