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Results for “Mice, Knockout”

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PubMed2026

Generation of miR-141/200c conditional knockout mice from knockout-first, reporter-tagged parent and functional validation of the floxed allele.

MicroRNAs (miRNAs) of the miR-200 family-specifically miR-141 and miR-200c-regulate neurogenesis, differentiation, and epithelial-mesenchymal transitions in development. Dysregulation of these miRNAs is associated with several diseases including cancer and stroke. The Mirc13tm1Mtm/Mmjax mouse line, which targets the miR-141/200c cluster, was originally generated and described by Park et al. 2012 as a knockout-first, reporter-tagged insertion with conditional potential (conditional-ready) mouse line. Harnessing its full potential requires a two-step breeding process: breeding with FLP mice to excise the lacZ/neo cassette, then breeding with Cre to delete the floxed miRNA cluster (Park et al. 2012). However, many studies either bypassed removal of the lacZ/Neo cassettes and treated the mouse line as Mirc13 knockouts or bred directly with Cre mouse lines, which could lead to unpredictable recombination and genotypes. Here we show that retention of the lacZ/Neo cassette is associated with reduced expression of the neighboring genes Ptpn6, Phb2 and Atn1 in the olfactory bulb, and that these genes are expressed normally once the cassette is excised. We therefore recommend a validated two-step FLPo-then-Cre breeding plan for this line, together with case-by-case allele validation for other knockout-first, reporter-tagged mouse lines.

Animals↗

PubMed2025

Abnormal mitochondrial structure and function in brown adipose tissue of SLC35A4-MP knockout mice.

Uncovering the role of upstream open reading frames (uORFs) challenges conventional views of one protein per messenger RNA and reveals the capacity of some uORFs to encode microproteins that contribute to cellular biology and physiology. This study explores the functional role of a recently identified mitochondrial microprotein, SLC35A4-MP, in the brown adipose tissue of mice. Our findings reveal dynamic regulation of SLC35A4-MP expression during primary brown adipocyte differentiation in vitro and during cold exposure or high-fat diet (HFD)-induced obesity in mice. Using a knockout mouse model, we show that loss of SLC35A4-MP disrupts mitochondrial lipid composition, decreasing cardiolipins and phosphatidylethanolamine in brown adipose tissue from HFD-fed mice. SLC35A4-MP deficiency also impairs mitochondrial activity, alters mitochondrial number and morphology, and promotes inflammation. Knockout mice accumulate acylcarnitines during cold exposure, indicating defective fatty acid oxidation. These findings reveal SLC35A4-MP as a previously unrecognized microprotein in regulating mitochondrial function and tissue lipid metabolism, adding to the growing list of functional endogenous microproteins.

Animals↗

PubMed2026

Age-dependent reorganization of behavioral and striatal function in Cntnap2 knockout mice.

Autism spectrum disorder (ASD) is characterized by persistent deficits in social communication and the presence of restricted and repetitive behaviors. While ASD has a neurodevelopmental origin, it remains a lifelong condition, yet little is known about how its behavioral and neural features evolve across adulthood. Here, we investigated behavioral, synaptic, and structural alterations across the transition from early to mature adulthood in Cntnap2 knockout mice, a widely used model of ASD. Using a longitudinal behavioral approach combined with electrophysiological recordings and morphological analysis, we show that KO mice exhibit increased stereotyped and repetitive behaviors and reduced exploratory activity at both ages. However, detailed analysis of behavioral patterns revealed age-dependent differences, with early adult KO mice displaying increased behavioral persistence that later evolved into distinct patterns of behavioral sequences. These behavioral changes were associated with alterations in inhibitory synaptic transmission in the dorsolateral striatum (DLS), including changes in spontaneous inhibitory postsynaptic current (sIPSC) frequency and temporal structure. In parallel, mature adult KO mice showed structural remodeling of spiny projection neurons, characterized by increased distal dendritic arborization and age-dependent organization of dendritic spines. Together, our findings demonstrate that ASD-related alterations are not static but evolve across adulthood, revealing a multi-level reorganization of behavioral, synaptic, and structural features. These results highlight the importance of considering adulthood stages in ASD and provide new insights into the dynamic nature of the condition.

Animals↗

PubMed2026

Conditional eIF2A Deletion Suggests Extra-Adipose Mechanisms Underlying Metabolic Syndrome in Total-Body eIF2A Knockout Mice.

Dynamic regulation of protein synthesis is essential for metabolic homeostasis, with translation initiation playing a key role in this process. Emerging evidence strongly indicates that in addition to canonical eukaryotic initiation factors (e.g., eIF2, eIF4E) non-canonical factors, such as eukaryotic initiation factor 2A can modulate metabolic homeostasis. eIF2A is a highly conserved eukaryotic protein originally proposed to function analogously to bacterial IF2, promoting initiator Met-tRNAi recruitment to the 40S ribosomal subunit, though its precise mechanism remains debated. To investigate its organismal role, we have previously generated the total-body eIF2A knockout mouse, which revealed eIF2A functions in lipid homeostasis, glucose tolerance, insulin sensitivity, and susceptibility to metabolic syndrome. To further determine whether adipose tissue drives these phenotypes, we presently generated adipose-specific eIF2A knockout mice. Despite dysregulation of some key adipokines, including for example, adiponectin, these mice did not develop metabolic syndrome, even under high-fat diet conditions, indicating that adipose tissue specific deficiency of eIF2A is insufficient to reproduce the metabolic defects observed in total-body knockout. However, we found that eIF2A deficiency in the liver of the total body eIF2A-KO mice can independently drive metabolic syndrome components via translational control of Lpin1 (a phosphatidate phosphatase and a transcriptional coactivator) that controls hepatic lipid storage and metabolism. eIF2A deficiency in the liver leads to disruption of fatty acid oxidation and the production of ketone bodies, not observed in adipose-specific eIF2A knockout mice. Our findings suggest that systemic metabolic effects observed in the total body eIF2A-KO mice may arise from coordinated functions across multiple organs.

adipose tissue↗

PubMed2026

Molecular characterization of Cdh12-SCON conditional knockout mice reveals unexpected splicing changes.

Functional validation of candidate genes in congenital anomalies of the kidneys and urinary tract (CAKUT) and other disorders is essential for translating genetic discoveries into clinical applications. Conditional knockout mouse models are indispensable for studying gene function in complex organ systems. The Short Conditional intrON (SCON) system accelerates the generation of such models by inserting the artificial SCON into a coding exon. SCON is designed to be spliced out after transcription, without affecting gene expression. Upon Cre activity, SCON is converted into the ΔSCON allele which cannot be spliced out, introducing premature termination codons (PTCs) to inactivate the gene. Previous validation of the SCON system in mice has focused primarily on phenotypic outcomes. Here, we provide a molecular characterization of the SCON system in Cdh12-a candidate gene implicated in kidney damage in CAKUT. We found that both Cdh12SCON and Cdh12ΔSCON alleles caused unintended skipping of the exon downstream of the insertion site, culminating in a frameshift and PTC. Consequently, the Cdh12SCON allele led to a ~ 25% reduction in mRNA expression, indicating that it was not transcriptionally inert as designed. Despite unintended exon skipping, the Cdh12ΔSCON allele still effectively suppressed mRNA expression. These findings highlight the importance of transcript-level characterization of engineered alleles prior to functional studies, as artefactual splicing events may occur across multiple gene-targeting strategies, including artificial intron-based conditional alleles as shown here.

Animals↗

PubMed2025

Validation and Optimization of Breeding Strategy for miR-141/200c Knockout Mice to Eliminate Off-Target Gene Silencing using FLPo Deleter.

MicroRNAs (miRNAs) of the miR-200 family specifically miR-141 and miR-200c regulate neurogenesis, differentiation, and epithelial-mesenchymal transitions in development and several diseases including cancer and stroke. The STOCK Mirc13tm1Mtm /Mmjax mouse line, which targets the miR-141/200c cluster, was originally generated and described by Park et al. 2012 as a conditional "knockout-first" allele requiring a two-step breeding strategy: FLP recombination to excise lacZ/neo cassettes followed by Cre recombination to delete the floxed miRNA cluster (1). However, subsequent studies either bypassed this step and reported knockouts based on direct crosses with Cre mouse lines, leaving residual lacZ/neo sequences that may silence upstream elements or introduce transcriptional artifacts or rare studies used less efficient FLPe Deleter mice. Here, we present a detailed and refined strategy to conditional miR-141/200c knockouts mice using FLPo Deleter mice to efficiently eliminate lacZ/neo cassettes. Our approach not only confirmed complete deletion of miR-141 and miR-200c in various organs such olfactory bulbs and lungs where these miRNAs are robustly expressed using various approach such as genotyping qPCR validation and in situ hybridization but showed that without the use of FLPo deleter mice deletion of miR-141/200c cluster amy also lead to loss of several close proximity physiologically important genes such as ptpn6, phb2, atn1 and eno1. By restoring a clean floxed allele using FLPo deleter mice prior to Cre deletion, we establish a reliable and interpretable mouse model for dissecting the roles of the miR-141/200c cluster miRNA in various disease models.

Journal Article↗

PubMed2026

AKAP12 Regulates Perivascular OPC Accumulation in the Corpus Callosum During Cerebral Hypoperfusion.

Oligodendrocyte precursor cells (OPCs) have been reported to interact with cerebral microvessels, but the extent and spatiotemporal regulation of this relationship across maturation and hypoperfusion-induced stress remain incompletely defined. Here, we quantified OPC-vessel relationships in the mouse corpus callosum using PDGFR-α/OLIG2/CD31 immunohistochemistry and distance-based spatial analysis, classifying OPCs within 10 μm of CD31+ vessels as perivascular OPCs. We show that while total OPC density decreases from development to adulthood, the proportion of perivascular OPCs increases in the mature brain. Under cerebral hypoperfusion induced by bilateral common carotid artery stenosis (BCAS), OPC density and the enrichment of perivascular OPCs were increased by Day 7 and remained elevated through Days 14-28. Proliferative OPCs (Ki67-positive OPCs) were preferentially observed within the vessel-proximal domain, indicating that the perivascular compartment functions as a stress-responsive proliferative niche. To identify regulators of this response, we focused on A-kinase anchoring protein 12 (AKAP12), a scaffolding protein expressed in vascular cells. In middle-aged Akap12 global knockout mice subjected to BCAS, hypoperfusion-induced OPC increase was preserved, but perivascular accumulation was reduced. This defect was accompanied by increased IgG leakage without a corresponding reduction in vascular area density, suggesting that AKAP12 supports the integrity of the perivascular microenvironment required for OPC niche remodeling. Together, these findings reveal the perivascular niche as a hypoperfusion-responsive compartment for OPC activation and suggest that AKAP12-dependent vascular barrier integrity contributes to the maintenance of this oligovascular niche.

Animals↗

PubMed2025

COXFA4L3 enhances mitochondrial complex IV function to boost ATP synthesis and drive sperm motility.

COXFA4L3 is a testis-specific cytochrome c oxidase subunit that enhances mitochondrial complex IV activity during spermatogenesis. From the analysis of Coxfa4l3 knockout mice, the isoform switch from COXFA4 to COXFA4L3 may increase the potential COX activity, although this activity does not appear in the testis. This latent enhancement becomes evident in sperm, where COXFA4L3 promotes higher respiratory capacity, increasing sperm motility and ATP production. These findings indicate that COXFA4L3 is a key regulator of mitochondrial energy metabolism and may provide insights into the mechanisms underlying male infertility.

Electron Transport Complex IV↗

PubMed2026

The Staphylococcus aureus serine protease-like protein B is a potent allergen in a murine asthma model.

BACKGROUND: Asthma is associated with Staphylococcus aureus colonization. Two hypotheses were proposed to explain this phenomenon: (1) the allergic environment in asthma favors S. aureus colonization and (2) S. aureus colonization creates a pro-allergic environment. Since several S. aureus virulence factors, such as the serine protease-like protein (Spl) B, elicit a type 2 biased immune response, we asked whether the pathogen itself can cause asthma. OBJECTIVE: Test the ability of recombinant SplB of S. aureus to sensitize mice and induce allergic airway inflammation (AAI). METHODS: Mice were treated with repeated intratracheal inoculations of either catalytically active SplB or an inactive mutant. AAI was assessed by evaluating airway hypersensitivity, immune cell infiltration, cytokines, mucus production, fibrosis, and specific serum IgE. We compared the outcome between wild-type and gene-deficient C57BL/6J mice, including recombination-activating gene knockout mice (Rag2-/-), interleukin-33 knockout mice (Il33-/-), and protease-activated receptor 2 knockout mice (F2rl1-/-). RESULTS: Intratracheal exposure to SplB sensitized the mice and caused eosinophilic airway inflammation and hyperresponsiveness. The development of asthma required both the proteolytic activity of SplB and a functional adaptive immune system. The soluble protease sensor IL-33 was necessary for eosinophil tissue invasion, whereas the membrane-bound protease sensor PAR2 was not. CONCLUSION: The serine protease SplB of S. aureus is a potent allergen. Based on this finding we propose a third mechanism to explain the relationship between S. aureus colonization and asthma: S. aureus can release allergens, such as SplB, that sensitize individuals and lead to the development of asthma.

Allergy↗

PubMed2026

Targeting CD44 reverses sphingomyelin-induced oligodendrocyte maturation arrest in acid sphingomyelinase deficiency.

Loss-of-function mutations in the smpd1 gene cause acid sphingomyelinase deficiency (ASMD). Early neurodegeneration and lethality characterize its infantile neurovisceral form (type A). While neuronal dysfunction was traditionally considered the primary driver of the pathology, recent evidence suggests that dysmyelination and microgliosis are not merely secondary features. Specifically, myelin debris undermines the protective role of microglia, contributing to neuroinflammation and neuronal death. Herein, we examined central myelin and oligodendrocyte lineage progression in ASM knockout mice. We show that early-onset dysmyelination results from compromised oligodendrocyte maturation driven by aberrant sphingomyelin-mediated signaling. Transcriptomic profiling revealed that mature oligodendrocytes in these mice retain a gene expression signature similar to oligodendrocyte precursor cells, indicating a differentiation arrest. The cell adhesion molecule CD44 remained significantly upregulated in mature ASMko oligodendrocytes. Pharmacological inhibition of CD44 with verbascoside rescued oligodendroglial maturation in primary culture. Verbascoside administration in vivo restored myelin integrity and improved motor behavior. These findings establish that sphingomyelin homeostasis is critical for oligodendrocyte maturation and identify myelin defects as both primary pathological triggers and therapeutic targets for ASMD with neurologic symptoms.

Animals↗

PubMed2025

Deep inflations maintain surfactant function and alveolar fluid balance in lungs with reduced surfactant protein B levels during mechanical ventilation.

Surfactant protein B (SP-B) is essential for surface tension reducing function of pulmonary surfactant and alveolar unfolding processes during inspiration. SP-B is reduced early in acute lung injury. Hence, we hypothesize that 1) reduced SP-B expression increases susceptibility to ventilation-induced lung injury (VILI), and 2) deep inflations (DI) are protective against VILI. Conditional SP-B knockout mice were randomized into OFF (reduced SP-B) and ON groups (normal SP-B) and subjected to mechanical ventilation at zero end-expiratory pressure. Over 4 h of ventilation, either 4 or 16 DI were administered. Lung mechanics were recorded, and pulmonary structure was quantified by design-based stereology. Inflammatory cells and bulk RNA sequencing were measured in bronchoalveolar lavage (BAL) and tissue, respectively. No differences in inflammatory cells in BAL were detected between ON and OFF groups. During ventilation, alveolar derecruitment-related increase in elastance was most pronounced in OFF-4DI but reversible by DI so that lung mechanics did not worsen. Finally, volumes of the alveolar liquid lining layer and the intracellular surfactant were largest, whereas the surface area of the apical plasma membrane of type II pneumocytes was smallest in OFF-4DI, suggesting impaired surfactant secretion. A higher frequency of DI prevented these abnormalities. Electron microscopy revealed disorganized tight junctions between alveolar epithelial cells in OFF-4DI, which was linked with decreased expression of genes relevant to the apical junctional complex. Reduced SP-B resulted in a progressive increase in surface tension and a disturbed fluid balance without triggering definite VILI. Maintenance of residual surfactant function is highly dependent on DI in conditions of reduced SP-B levels.NEW & NOTEWORTHY Surfactant protein B (SP-B) is critical for efficient surfactant function in the lung. Reduced SP-B levels occur at an early stage of acute lung injury and impair alveolar unfolding. In this study, we demonstrate that mechanical ventilation of lungs with reduced SP-B levels does not trigger ventilation-induced lung injury but results in disbalance of alveolar fluid volume and increase in surface tension due to failure of surfactant maintenance. Deep inflations prevent these ventilation-induced effects.

Animals↗

PubMed2026

Pathogenic role of serpin B3-positive neutrophils in reinforcing thrombus stiffening during ischemic stroke.

The contribution of immune cells to thrombus architecture and mechanical properties in acute ischemic stroke (AIS) remains poorly understood. Using 3-dimensional imaging and multiplex staining, we mapped immune cells in human stroke thrombi and identified neutrophils as the dominant population. Analysis of 19 thrombi confirmed their positive correlation with collagen, increased stiffness, and poorer clinical outcomes. To preserve spatial context, we developed a laser capture-based proteomic workflow and analyzed thrombus neutrophils from 34 patients with AIS stratified by 90-day outcomes, followed by validation in an independent cohort of 22 patients. Proteomic analysis revealed serpin B3 as a neutrophil-enriched protein strongly correlated with poor prognosis. In murine models of ferric chloride-induced carotid artery thrombosis and middle cerebral artery occlusion, experiments using wild-type, neutrophil-depleted, and Serpinb3a knockout mice demonstrated that neutrophil-derived serpin B3 promotes early thrombus formation, enhances collagen deposition, and contributes to progressive thrombus stiffening. Mechanistically, serpin B3 secreted by neutrophils amplifies thrombus stiffness through upregulation of transforming growth factor β1, neutrophil extracellular traps, and COL1A1. Targeted Serpinb3a knockdown delayed vascular occlusion, improved thrombolysis efficiency, and resulted in better neurological recovery. Collectively, these findings identify a neutrophil-driven mechanism underlying thrombus stiffening and establish SERPINB3 as both a prognostic biomarker and a promising therapeutic target in AIS. This project has been registered with the Chinese Clinical Trial Registration Platform (https://www.chictr.org.cn/index.html) and has successfully passed the review process (registration number: ChiCTR2300077911).

Animals↗

PubMed2025

The RNA-binding protein TRIM71 is essential for hearing in humans and mice and times auditory sensory organ development.

The RNA-binding protein TRIM71 is essential for brain development, and recent genetic studies in humans have identified TRIM71 as a risk gene for congenital hydrocephal-us (CH). Here, we show that monoallelic missense mutations in TRIM71 are associated with hearing loss (HL) and inner ear aplasia in humans. Utilizing conditional Trim71 knockout mice carrying a CH and HL-associated mutation, we demonstrate that loss of TRIM71 function during early otic development (embryonic day 9 to 10) causes severe HL. While inner ear morphogenesis occurs normally in Trim71 knockout mice, we find that early otic loss of TRIM71 function disrupts the highly stereotyped timing of cell cycle exit and differentiation within the inner ear auditory sensory organ (cochlea), resulting in the premature formation and innervation of mechanosensory hair cells. Transcriptomic profiling of Trim71-deficient cochlear progenitor cells identifies Inhba and Tgfbr2 as targets of TRIM71 repression, and our analysis of Inhba-Tgfbr1 double knockout mice indicates that TRIM71 maintains hair cell progenitors in a proliferative and undifferentiated state by restricting TGFβ-type signaling. Characterization of hair cells and their associated neurons in adult Trim71 knockout mice revealed reduced presynaptic terminals and neuronal degeneration in the outer hair cell region, providing a basis for the observed hearing deficits in Trim71 knockout mice.

Animals↗

PubMed2026

Elevated Triggering Receptor Expressed on Myeloid Cells 2 Expression in Tumor-Associated Macrophages Suppresses Cytotoxic T Cell Infiltration and Facilitates Immune Escape in Colorectal Cancer.

BACKGROUND & AIMS: Emerging evidence supports a crucial role for tumor-associated macrophages in shaping the immunosuppressive tumor microenvironment. Furthermore, research has identified that the triggering receptor expressed on myeloid cells 2 has immunomodulatory functions. The present investigated the potential effect of triggering receptor expressed on myeloid cells 2 expression in tumor-associated macrophages on facilitating immune evasion in colorectal cancer. METHODS: Immunohistochemical analysis of clinical specimens, complemented by extensive data mining from The Cancer Genome Atlas, revealed a significant upregulation of triggering receptor expressed on myeloid cells 2 in colorectal cancer-associated tumor-associated macrophages, with this upregulation exhibiting a correlation with poor patient prognosis. RESULTS: Mechanistically, triggering receptor expressed on myeloid cells 2+ tumor-associated macrophages were found to drive fibroblast activation through transforming growth factor-β signaling, inducing fibroblast-activated protein-positive cancer-associated fibroblasts that secrete collagen I/III to establish dense peritumoral barriers. Spatial profiling revealed that these fibrous structures physically impede CD8+ T-cell infiltration, restricting cytotoxic lymphocytes to stromal compartments. Intriguingly, triggering receptor expressed on myeloid cells 2 deficiency enhanced the secretion of matrix metalloproteinase 13 by macrophages, thereby promoting extracellular matrix degradation and improving T-cell penetration. In vivo, Trem2-knockout mice showed a reduction in tumor growth with enhanced intratumoral CD8+ T-cell infiltration compared with wild-type controls. CONCLUSIONS: Our findings establish triggering receptor expressed on myeloid cells 2+ tumor-associated macrophages as central regulators of stromal remodeling and suggest that therapeutic targeting of the triggering receptor expressed on myeloid cells 2/transforming growth factor-β/fibroblast-activated protein pathway may overcome immune resistance in patients with colorectal cancer.

Colorectal Neoplasms↗

PubMed2026

Mitochondrial translocation of DNMT3L suppresses oxidative phosphorylation and restrains megakaryopoiesis.

DNMT3L, a catalytically inactive member of the DNA methyltransferase family, is identified here as a negative regulator of megakaryopoiesis. In K562 cells undergoing PMA-induced megakaryocytic differentiation, DNMT3L protein levels declined progressively, and shRNA-mediated depletion enhanced differentiation, whereas overexpression attenuated it. Consistent with these findings, Dnmt3l-knockout mice exhibited elevated peripheral blood platelet counts and expanded bone marrow megakaryocytes. Mechanistically, megakaryocytic differentiation triggered rapid mitochondrial translocation of DNMT3L within 6 h; mitochondrial DNMT3L suppressed oxidative phosphorylation (OXPHOS) capacity and ATP production and downregulated mitochondrial-encoded genes spanning Complex I, III, IV, and ATP synthase, without altering mitochondrial DNA copy number. This metabolic suppression was mediated through compartment-specific remodeling of DNMT3L-containing protein complexes: upon differentiation, DNMT3L selectively dissociated from DNMT1 and DNMT3B in mitochondria, relieving the repressive constraint on OXPHOS, whereas in the nucleus DNMT3L remained associated with DNMT3A, which concomitantly accumulated during differentiation. These findings reveal a previously unrecognized mechanism by which a catalytically inactive epigenetic co-regulator spatially redistributes to coordinate mitochondrial metabolic output with nuclear epigenetic control, thereby facilitating terminal megakaryocytic maturation.

Animals↗

PubMed2026

MLL4 protects cardiomyocytes against ischemia-reperfusion injury through STAT3-mediated mitochondrial function.

Myocardial ischemia-reperfusion injury (MIRI) is an inevitable pathophysiological response during the revascularization process following myocardial ischemia. Despite its clinical significance, effective targeted therapies for MIRI remain an unmet medical need. Mixed-lineage leukemia 4 (MLL4), a member of the SET family of histone methyltransferases, exhibits particular methyltransferase action toward histone H3 lysine 4 (H3K4). This study establishes a protective role for MLL4 in MIRI pathogenesis. Utilizing cardiomyocyte-specific Mll4 knockout mice and an in vivo ischemia-reperfusion (I/R) model induced by left anterior descending coronary artery ligation, we observed significant upregulation of MLL4 expression in cardiac tissue following I/R. Genetic ablation of Mll4 in cardiomyocytes markedly exacerbated both acute and chronic phases of MIRI. In vitro, Mll4 knockdown in neonatal rat cardiomyocytes (NRCMs) amplified mitochondrial dysfunction and apoptosis under hypoxia/reoxygenation (H/R) conditions. Integrated analysis of Cleavage Under Targets and Tagmentation sequencing (CUT&Tag-seq) and RNA sequencing (RNA-seq) revealed that Mll4 deficiency induces a pronounced reduction in H3K4 monomethylation (H3K4me1) and histone H3 lysine 27 acetylation (H3K27ac) enrichment at the Stat3 genomic locus. Mechanistically, MLL4 functions as a transcriptional activator of Stat3 by depositing H3K4me1 and H3K27ac, thereby facilitating STAT3 transcription. This regulatory cascade ultimately governs STAT3-dependent mitochondrial homeostasis. Collectively, these findings identify MLL4 as a critical epigenetic regulator of MIRI and suggest its therapeutic targeting may offer a promising strategy for mitigating reperfusion injury.

Animals↗

PubMed2026

Impact of NRSN2 deficiency on memory: Altered excitatory synaptic plasticity associated with reduced expression of NMDA receptor subunits and impaired LTP in the hippocampus.

Our earlier human studies identified NRSN2 (Neurensin-2), a neuronal-specific vesicular protein, as a candidate gene contributing to 20p13 microdeletion syndrome, yet the functional consequences of NRSN2 deficiency in the nervous system remain poorly understood. To explore the role of Nrsn2 in neurodevelopment and cognitive function, we utilized previously generated homozygous Nrsn2 knockout mice (Nrsn2-/-) and performed a series of behavioral, morphological, and electrophysiological analyses. Behaviorally, Nrsn2-/- mice exhibited mild locomotor impairment, as assessed by gait analysis at 4 and 8 weeks of age, as well as significant deficits in spatial learning and memory (Morris water maze) and fear memory (passive avoidance test) at 8 weeks. Morphometric analysis suggested no overt alterations in dendritic complexity or spine density in hippocampal CA1 pyramidal neurons or cerebellar Purkinje cells without developmental malformation. Electrophysiological recordings and immunoblotting analyses may reflect region-specific synaptic alterations. In the hippocampus, expression levels of the NMDA receptor subunits GluN1 and GluN2A were reduced at 4 weeks of age. Consistently, CA1 pyramidal neurons displayed decreased sEPSC frequency with unchanged amplitude under the conditions examined. In addition, an imbalance in hippocampal excitatory/inhibitory transmission was observed, as reflected by altered sEPSC frequency in the absence of changes in sIPSC frequency. In cerebellar Purkinje cells, GluA1-containing AMPA receptors were selectively downregulated, accompanied by reduced frequency and amplitude of sEPSCs and a selective decrease in sIPSC frequency, indicating both excitatory and inhibitory synaptic dysfunction in this region. Collectively, these findings indicate that Nrsn2 deficiency is accompanied by altered excitatory synaptic transmission and reduced long-term potentiation (LTP) at 8 weeks of age, despite preserved dendritic architecture as assessed by Golgi staining. These synaptic and plasticity deficits occur alongside the observed cognitive and motor impairments in Nrsn2⁻/⁻ mice. This study provides a descriptive phenotypic characterization of Nrsn2 deficiency and offers initial insights into the neurobiological role of NRSN2 and its contribution to neurodevelopment, learning, and memory.

Animals↗

PubMed2025

Identification of a PRDM1-regulated T cell network to regulate atherosclerotic plaque inflammation.

BACKGROUND: Inflammation is a key driver of atherosclerosis, yet the mechanisms sustaining inflammation in human plaques remain poorly understood. This study uses a network-based approach to identify immune gene programs involved in the transition from low- to high-risk (rupture-prone) human atherosclerotic plaques. METHODS: Expression data from human carotid artery plaques, both stable (low-risk, n = 16) and unstable (high-risk, n = 27), were analyzed using Weighted Gene Co-expression Network Analysis (WGCNA). Bayesian network inference, operated on the eigengene values from the WGCNA, further extended the WGCNA analysis, and similarity to the signature of T cell subsets was validated in single-cell RNA sequencing data of human plaques, and a loss-of-function study in a mouse model of atherosclerosis. In silico drug repurposing was performed to identify potential therapeutic targets. RESULTS: Our analysis revealed a distinct gene module with a prominent T cell signature, particularly in unstable plaques. Key regulatory factors, RUNX3, IRF7 and in particular PRDM1, were significantly downregulated in plaque T cells from symptomatic versus asymptomatic patients, indicating a protective role. Additionally, as PRDM1 is downstream of IRF7, we opted for PRDM1 as a key target. T cell-specific Prdm1 deficiency in Western-type diet fed Ldlr knockout mice featured accelerated plaque progression. Finally, as PRDM1 targeting drugs are not yet available, we performed in silico drug repurposing, identifying EGFR inhibitors as promising therapeutic candidates. CONCLUSIONS: This study highlights a PRDM1-regulated T cell network that distinguishes high-risk from low-risk plaques and demonstrates the regulatory role of T cell PRDM1 in controlling atherosclerosis, positioning this pathway as a promising therapeutic target.

Plaque, Atherosclerotic↗