Journal of Cellular and Molecular Medicine

Background: Platelets are critical drivers of thrombo-inflammatory responses in different cardiovascular diseases. Abdominal aortic aneurysm (AAA) is a progressive, life-threatening vascular disorder mainly characterised by chronic inflammation, extracellular matrix degradation, and the formation of a platelet-rich intraluminal thrombus (ILT). Experimental and clinical evidence identified platelets as main players in AAA pathology as evidenced by elevated platelet activation and procoagulant activity that critically contribute to AAA progression. Methods: The present study investigated the contribution of glycoprotein (GP)Ib alpha, the von Willebrand factor (VWF)-binding subunit of the platelet GPIb-IX-V complex, to AAA initiation and progression in experimental AAA using the ePPE mouse model and in patients. Results: Genetic ablation of platelet GPIb alpha significantly attenuated early aneurysm expansion in experimental AAA, indicating a critical role for GPIb alpha during the initial stages of aneurysm development. This initial effect was compensated at later time points showing no differences in aneurysm progression between groups. Notably, genetic deletion of GPIb alpha induced a constitutively hyperactive platelet phenotype already in naive mice that was further amplified during experimental AAA. This elevated platelet hyperactivity was mainly due to increased GPVI activation of platelets 28 days post-surgery. To assess the clinical relevance, spatial profiles of human ILT specimens from patients with AAA were analysed. In the ILT, we detected a highly compartmentalised distribution of GPIb alpha and VWF with pronounced enrichment within the luminal layer. In parallel, circulating VWF activity as well as platelet surface expression of GPIb alpha were significantly increased in patients with AAA. Conclusion: Collectively, these findings identify a dysregulated GPIb alpha-VWF axis in human AAA pathology, mainly characterised by enhanced platelet GPIb alpha surface expression and increased activity of circulating VWF.

BackgroundPremature ovarian insufficiency (POI) is a condition affecting female fertility e.g., in the context of autoimmune disease. A recent proof-of-concept study showed that B-cell depletion with rituximab (RTX) temporarily restored ovarian function in patients with autoimmune POI. However, the underlying immunological mechanisms behind this response is unknown. ObjectivesTo characterize B- and T-cell phenotypes before and after RTX therapy in the above-mentioned patients and associations with autoantibody levels and treatment response. MethodsCryopreserved cell samples were available from six autoimmune patients with POI, four of whom were positive for autoantibodies against steroidogenic enzymes (21OH, 17OH and/or SCC). Patients received RTX and blood samples were collected at baseline, second infusion (2 weeks), 3, 8 and 12 months. Peripheral B- and T-cell phenotypes were analysed using spectral flow cytometry and correlated with autoantibody levels. ResultsAt baseline, patients displayed signs of B-cell activation by alteration in subset composition compared to matched controls. Upon closer analysis, patients positive for steroidogenic enzyme autoantibodies had significantly increased frequency of CXCR3+switched memory (SWM) B-cells than autoantibody-negative patients, which correlated positively with anti-17OH and-SCC autoantibody levels. In parallel, increased Th1 cell frequencies were also observed in the same patient group. Longitudinal analyses showed expected B-cell depletion followed by repopulation after RTX. Changes in T-cell subsets were observed at 8 months with reduced frequencies of Th1 and Tfh cells. ConclusionAutoimmune POI displayed altered B- and T-cell subsets implicating cell crosstalk, immune cell infiltration to sites of inflammation such as ovaries, and presence of Th1-driven immunopathogenesis. Key messagesO_LIIncreased CXCR3+SWM B cells and Th1 cells were found in patients with autoimmune POI who were positive for autoantibodies against steroidogenic enzymes. C_LIO_LICXCR3 expression on SWM B cells positively associated with anti-17OH and anti-SCC autoantibody levels. C_LIO_LIRTX induced rapid B-cell depletion followed by repopulation and a delayed T-cell effect at 8 months with reduced Th1 and Tfh cell frequencies. C_LI Capsule summaryRTX has recently been shown to restore fertility in autoimmune POI. Lymphocyte profiling identified Th1 bias accompanied by CXCR3+memory B cells that correlate with autoantibody levels. B-cell depletion appears to temporarily alleviate ovarian autoimmunity and ameliorate physiological function.

Background: Activation of the renin-angiotensin system (RAS) contributes to aortic diseases caused by fibrillin-1 haploinsufficiency (Fbn1C1041G/+). However, whether RAS activation influences mitral valve disease associated with FBN1 variants remains undefined. This study determined whether inhibition or augmentation of the RAS affects mitral valve pathology in Fbn1C1041G/+ mice. Methods: Angiotensinogen (AGT) antisense oligonucleotides (ASOs) were administered for 12 weeks to inhibit the RAS in male and female Fbn1C1041G/+ mice. To augment the RAS, mice were infused with angiotensin II (AngII; 1,000 ng/kg/min) for 28 days. Mitral valve and heart function were monitored by ultrasound. At termination, hearts were dissected free and tissue sectioned to assess mitral valve leaflet thickness and pathology. Results: Mitral valve leaflet thickness was significantly increased in Fbn1C1041G/+ mice compared to Fbn1+/+ littermates of both sexes. ASO-mediated AGT inhibition did not alter this phenotype despite markedly reduced plasma AGT concentrations. AngII infusion increased mitral valve leaflet thickness in Fbn1C1041G/+ mice with increased proteoglycan and collagen content, while exerting minimal effects in Fbn1+/+ mice. Twenty-five percent of AngII-infused Fbn1C1041G/+ mice died of non-vascular causes. Ultrasound showed mitral valve dysfunction in AngII-infused Fbn1C1041G/+ mice. Grossly expanded left atria were common in AngII-infused Fbn1C1041G/+ mice. These markedly enlarged left atria contained increased fibrosis, macrophage accumulation, and platelet-rich masses. Conclusions: Mitral valves of Fbn1C1041G/+ mice did not respond to AGT inhibition but were markedly more susceptible to AngII infusion, with greater increases in thickness and compositional changes than mitral valves of Fbn1+/+ mice. In addition, AngII promoted mitral valve dysfunction that were associated with pronounced left atrial pathology.

Background: Autophagy is a homeostatic pathway supporting stress adaptation and is dysregulated in atherosclerosis. Its potential as a biomarker or therapeutic target in atherosclerotic vascular disease (ASVD) remains incompletely defined. We measured autophagic flux in peripheral blood mononuclear cells (PBMCs) from patients with peripheral arterial disease (PAD) or carotid stenosis (CS), compared with healthy controls, and explored clinical outcome associations. Methods: Ninety-four patients with PAD or CS and 19 healthy controls were studied. Autophagic flux was quantified from fresh blood using a validated ex vivo chloroquine inhibition ELISA measuring LC3BII accumulation. Major adverse cardiovascular events (MACE) and major adverse limb events (MALE) were ascertained over a median follow up of 828 days. Results: The ASVD cohort comprised claudication (n = 16), chronic limb threatening ischemia (CLTI; n = 49), and CS (n = 29). Autophagic flux was higher in ASVD than controls (mean 281.4 vs. 182.3 ng LC3BII/mg protein/h; p < 0.0001) and remained independently associated after multivariable adjustment. Within CLTI, concurrent infection was associated with lower flux (p = 0.001), approaching control levels (p = 0.327). In CLTI, higher flux quartiles were associated with lower MACE risk, most strongly for quartile 3 (hazard ratio 0.07 vs. quartile 1, 95% CI 0.01 to 0.50; p = 0.009). Conclusion: Autophagic flux is elevated in PBMCs from ASVD patients, independent of age and sex. Attenuated flux in CLTI with concurrent infection may indicate autophagic exhaustion in advanced disease. The association between higher flux and lower MACE in CLTI suggests prognostic utility, warranting evaluation in larger prospective studies.

Abstract Background Liposarcoma is a rare cancer, comprising four major histological subtypes: well-differentiated, dedifferentiated, myxoid and pleomorphic liposarcoma. Therapeutic options remain limited for advanced disease, and additional biomarkers that may support biological characterization, diagnosis, or risk stratification are needed. Methods Bulk RNA sequencing (RNA-seq) was performed on paired tumour and adjacent non-tumour tissues from an analysable subset of 16 patients (22 tumour specimens) within a clinicopathological cohort of 21 patients. Differential gene expression analysis, principal component analysis, gene set enrichment (GSEA) analysis and single-sample GSEA (ssGSEA) were used to define subtype-specific transcriptional programs and imprinted-gene dysregulation. PEG10 expression was validated by RT-qPCR and RNA fluorescence in situ hybridization (FISH), and its cellular localization was explored by combined FISH and immunofluorescence for P53, vimentin, Ki67, and CD34. PEG10 expression in liposarcoma was further investigated in an external single-cell RNA-sequencing dataset of dedifferentiated liposarcoma. An exploratory survival analysis was performed in the pan-sarcoma TCGA-SARC cohort. Results Transcriptomic profiling identified distinct subtype-specific gene expression patterns and broad dysregulation of imprinted genes in liposarcoma compared with adjacent non-tumour tissue. Among all the imprinted genes, PEG10 showed a marked tumour-to-normal expression difference and good discriminatory performance between tumour and normal tissues in the discovery cohort (AUC=0.867). In the TCGA sarcoma cohort high PEG10 expression was associated with shorter overall survival. Immuno-FISH and single-cell analyses revealed that PEG10 was predominantly detected in tumour and proliferating cell populations. Importantly, PEG10 expression was higher in high-grade tumours. In bulk RNA-seq data, PEG10 expression correlated with hypoxia, extracellular matrix remodelling and invasion ssGSEA signatures. In the external single-cell RNA-seq dataset PEG10high tumours showed a reduced immune cell infiltration. Conclusions This study provides an integrated transcriptomic characterisation of liposarcoma and identifies PEG10 as a candidate tumour-associated biomarker linked to aggressive disease features. The diagnostic and prognostic value of PEG10 requires validation in larger, independent, subtype-balanced liposarcoma cohorts, and its potential therapeutic relevance requires direct functional investigation.

ABSTRACT Objective: Skeletal muscle growth rate differs substantially among diverse pig breeds. In the present study, RNA-seq was performed to identify differentially expressed genes (DEGs) across pig breeds with distinct growth rates. CCND2 showed obvious differential expression among pig breeds. Although CCND2 is essential for cell cycle control, its biological function in skeletal muscle differentiation has rarely been reported. This work aims to identify DEGs in pig breeds with different growth rates and explore CCND2 role in porcine skeletal muscle development. Methods: RNA-seq was performed to identify differentially expressed genes (DEGs) across pig breeds with distinct growth rates. Weighted gene co-expression network analysis (WGCNA) was used to identify gene modules potentially associated with skeletal muscle growth and development. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis was performed to validate the role of CCND2 in skeletal muscle differentiation. Results We identified 5,416, 4,846, and 2,777 DEGs in the Duroc pig (DU) vs. Jiangquan black pig (JQ), DU vs. Laiwu pigs (LW), and JQ vs. LW comparison groups, respectively. WGCNA identified two gene modules (lightgreen and darkmagenta) potentially associated with skeletal muscle growth and development. CCND2 exhibited differential expression in comparisons between DU vs JQ and DU vs LW, with higher expression observed in Duroc pigs. qRT-PCR analysis revealed that overexpression of CCND2 at day 6 (D6) of cell differentiation significantly increased the expression levels of CCND2 gene and markers of myogenic differentiation (p < 0.05). Conversely, knockdown of CCND2 significantly decreased the expression levels of CCND2 gene and myogenic differentiation markers (p < 0.05). Conclusions This study identified breed-specific DEGs and key gene modules in porcine skeletal muscle and verified that CCND2 promotes myogenic differentiation. These findings provide a genetic theoretical basis for further investigations into skeletal muscle growth and development. Keywords pig, skeletal muscle, transcriptome, WGCNA, CCND2

Myocardin (MYOCD) is the principal trigger-switch for vascular smooth muscle cell (VSMC) growth arrest and the cyto-contractile program of differentiation. While much is known about MYOCD-dependent VSMC differentiation, limited information exists as to its transcriptional regulation. Here, we report moderate mRNA expression of Myeloid Ecotropic viral Integration Site 1 (MEIS1) in both human and mouse VSMCs. MEIS1 mRNA is reduced in parallel with myocardin mRNA and protein under conditions of VSMC de-differentiation. Loss- and gain-of-Meis1 expression studies in cultured human VSMCs and the mouse carotid artery support MEIS1 as an activator of myocardin and VSMC differentiation. CRISPR-mediated knockout of the endogenous Meis1 gene in vitro and elicited lower levels of VSMC contractile markers and an increase in growth rate. Similarly, Femoral artery wire injury, in mice lacking Meis1 showed and increased of neointima formation. Mechanistically, we identified a conserved MEIS1 response element in the proximal promoter of myocardin, that appears to contribute to the promoter activity, suggesting a potential regulatory interaction. These results suggest a previously unrecognized role for the homeodomain protein MEIS1 in the activation of myocardin and the quiescent, VSMC differentiated state.

Background: Murine models are widely used to investigate cardiovascular disease (CVD), yet many established models rely on invasive surgery or genetic manipulation to induce hyperlipidemia and therefore may not fully capture the gradual cardiovascular consequences of mutant hematopoiesis. Tie2-Cre/-FF1/- (Tie2FF1) mice express JAK2V617F mutation in both hematopoietic and endothelial cells and develop spontaneous CVD on a standard chow diet. Methods: We applied a comprehensive, non-invasive cardiovascular phenotyping protocol to 1-year-old Tie2FF1 mice and age-matched controls. Assessments included transthoracic echocardiography, coronary flow reserve by Doppler ultrasound, quantitative analysis of coronary arteriolar structure and perivascular fibrosis, endocardial histology and subendocardial collagen deposition, and histologic evaluation of pulmonary and hepatic congestion. Results: Tie2FF1 mice demonstrated left ventricular dilation, increased cardiac mass, and mildly reduced systolic function without obstructive epicardial coronary disease. Coronary microvascular remodeling was evident by arteriolar narrowing and increased perivascular fibrosis, while coronary flow reserve was markedly reduced in an exploratory cohort. Endocardial endothelial disruption and increased subendocardial fibrosis were also observed. In addition, Tie2FF1 mice showed increased lung and liver weights, pulmonary fluid accumulation, alveolar septal thickening, pulmonary vascular fibrosis, hepatic sinusoidal dilatation, and centrilobular hepatocyte swelling, providing objective evidence of clinically relevant heart failure. Significance: These findings establish Tie2FF1 mice as a spontaneous, non-invasive model with features of coronary microvascular and endocardial endothelial dysfunction and heart failure with mildly reduced left ventricular ejection fraction. The integrated approach described here provides a practical framework for comprehensive murine cardiovascular phenotyping beyond traditional atherosclerosis- and surgery-based models.

Abstract Background: Chronic subdural hematoma (cSDH) remains a significant and increasingly prevalent cause of morbidity in older adults. Disease progression is sustained by de novo formed highly vascularized pseudomembranes and a persistent cycle of fluid accumulation and hematoma expansion. Although inflammatory and angiogenic pathways have been implicated in cSDH pathogenesis, the endothelial mechanisms underlying persistent vascular leak remain poorly understood. We investigated the cSDH vascular microenvironment in human patients and examined the role of vascular endothelial cadherin (VECAD) remodeling in cSDH endothelial dysfunction. Methods: Human cSDH membranes and fluid were evaluated by multiplex profiling, histology, immunofluorescence, immunoprecipitation, western blotting and exploratory bulk RNA sequencing. A human brain endothelial cell (HBEC) line was exposed to patient-derived cSDH fluid to assess VECAD remodeling, endothelial barrier permeability, and proliferation. Results: Multiplex profiling of patient-derived cSDH fluid detected mediators associated with endothelial cell (EC) activation, extracellular matrix remodeling, inflammation, and angiogenesis. In patient pseudomembranes, discontinuous VECAD coincided with erythrocyte extravasation. Two hyperdense (high-risk) specimens showed more extensive disruption than the hypodense (low-risk) specimen while vessel counts appeared similar. Bulk RNA sequencing identified an angiogenic environment and enrichment in cadherin regulation. A soluble VECAD (sVECAD) isoform was detected in cSDH fluid. Exposure of HBECs to patient-derived cSDH fluid increased EC proliferation, cytoplasmic VECAD (cVECAD) accumulation, and EC barrier permeability. Concurrent dexamethasone or minocycline treatment attenuated VECAD cleavage. Conclusions: VECAD disruption is a prominent feature of cSDH and is associated with EC barrier dysfunction. These findings support further evaluation of soluble VECAD as a candidate biomarker and of junction-preserving pathways as potential therapeutic targets.

Abstract Endothelial cell (EC) injury is central to the pathogenesis of various renal disorders, highlighting the critical importance of vascular repair for restoring organ health. However, due to limited access to human tissue during active regeneration, the exact reparative processes remain largely unknown. This study aimed to investigate regeneration mechanisms specifically within the glomerular microvasculature by utilizing a selective endothelial cell injury (ECI) model in mice.Lineage tracing identified the origin of regenerating ECs. To uncover the transcriptional dynamics driving these reparative changes, we combined single-cell RNA sequencing and Xenium spatial transcriptomics (ST), mapping distinct glomerular EC (gEC) subpopulations across different phases of injury and recovery. Apold1 emerged as a key regulatory candidate within this process. To functionally validate this gene's specific role during the regenerative phase, Apold1-deficient (Apold1-/-) mice underwent the ECI model. After showing that gECs regenerate primarily from local, pre-existing renal ECs, our transcriptomic analysis identified 10 distinct gEC subpopulations and revealed a complex temporal pattern of regeneration. This process begins with the expression of genes associated with inflammation, followed sequentially by endothelial cell (EC) migration, the activation of immediate early genes, vascular remodeling and cellular proliferation. Within this dynamic process, the EC-specific gene Apold1 was identified as a key regulatory candidate. Apold1-/- mice exhibited impaired endothelial regeneration, characterized by increased endothelial activation and greater immune cell infiltration seven days post-ECI. To our knowledge, this is the first study to elucidate the spatiotemporal mechanisms of glomerular endothelial cell regeneration. By identifying local gECs as the primary source of repair, and stablishing the change in their expression pattern during regeneration, as well as identifying Apold1 as an intrinsic regulator, we have laid the groundwork for future research on renal microvascular disorders.

Type 2 diabetes mellitus (T2DM) is a chronic disorder associated with obesity and hyperglycemia. T2DM is linked to significant clinical complications such as delayed wound healing and diabetic foot ulcers. Tumor necrosis factor-stimulated gene 6 (TSG-6) is a protein with multiple functions including regulation of cytokine binding to glycosaminoglycans in extracellular matrices and on vascular endothelial walls. Loss of TSG-6 in knockout mice increases skin inflammation and delays wound healing. Here, in both a genetic model (db/db mice) and a dietary model that simulates human T2DM (mice treated with a high-fat diet [HFD] and streptozotocin [STZ]), we observed sustained hyperglycemia and a reproducible delay in wound closure. TSG-6 expression was markedly reduced in diabetic skin in these models, both before injury and post wounding. HFD+STZ diabetic mouse wounds showed elevated levels of pro-inflammatory cytokines (IL-6, TNF-, and MIP-1) and lower levels of the anti-inflammatory cytokine IL-10, relative to normoglycemic mice. Re-introduction of TSG-6 protein into the wounds normalized healing rates, corrected abnormal cytokine expression levels, and increased macrophage accumulation in dermal and adipose compartments. Thus, T2DM is associated with reduced levels of TSG-6 in diabetic skin, which contributes to the pro-inflammatory milieu and the delay in wound closure.

Background. Cancer cachexia is a multifactorial syndrome characterized by substantial metabolic disturbances including systemic inflammation, and muscle atrophy, which may affect the regulation of iron metabolism in patients. This study aimed to characterize this regulation in two murine models of colorectal and pancreatic cancer, both associated with a high prevalence of cachexia. Methods. Histological, biochemical and molecular analyses were performed in serum, skeletal muscle, liver, spleen and tumor from UN-KC-6141 pancreatic tumor bearing mice and from ApcMin/+ mice (colorectal cancer model), both models exhibiting variable cachexia severity. Results. Both models induce cachexia, but diverge markedly in their regulation of iron metabolism. UNKC mice display reduced plasma iron availability (-9.6% transferrin saturation, p<0.001) without concomitant anemia, while hepatic hepcidin synthesis is upregulated (+100.6%, p<0.001) by inflammation, promoting ferroportin (FPN) downregulation (-42.4%, p<0.001) and iron sequestration in the spleen (+134% total iron content, p<0.001). In the atrophied gastrocnemius, iron concentration is preserved through increased ferritin (+86.6%, p=0.010) and hemoproteins (i.e., myoglobin, CYSC, COXIV) expression. Conversely, ApcMin/+ mice exhibit anemia together with hepatic and splenic iron depletion (-48.4%, p<0.001 and -84.9%, p<0.001, respectively). Hepcidin synthesis is downregulated (-99.9%, p<0.001) despite persistent inflammation, indicating that hypoxia and/or iron-deficiency signals probably predominate over the inflammatory pathway. FPN is markedly decreased (-94.2%, p<0.001) in the iron-depleted spleen despite low hepcidin. In the atrophied quadriceps of ApcMin/+ mice, iron deficiency is associated with decreased FPN and ferritin (-87.9%, p<0.001, and -38.4%, p=0.016, respectively), and increased TfR1 expression (+305%, p=0.107). Finally, tumor iron import may play a significant role in cachexia progression, as suggested by the association between tumor weight, tumor TfR1 protein levels and body weight loss in UNKC mice. Conclusion. These findings reveal cancer type-specific signatures of iron regulation in cachexia, which appear to be more driven by cancer type specific features than by cachexia severity itself, with skeletal muscle iron metabolism impaired mainly when cachexia is associated with anemia. This suggests that the clinical management of iron metabolism in cachectic patients should be guided by the underlying cancer type.

Background: Milrinone, a phosphodiesterase-3 (PDE-3) inhibitor, is widely used to improve cardiac output in pediatric and adult patients. Yet, developmental differences in myocardial responsiveness to milrinone remain incompletely understood. In this study, we examined the impact of postnatal maturation on the acute cardiac effects of milrinone using an intact guinea pig heart model. Methods: Neonatal (0-2 days), juvenile (4-10 days), and adult (> 6 months) guinea pig hearts were excised, Langendorff-perfused, and cardiac metrics were evaluated under basal conditions and in response to acute milrinone treatment (15 minutes, 10 and 100 M sequential concentrations). Pseudo-electrocardiograms were recorded continuously and left ventricular pressure measurements were performed under sinus rhythm and in response to external pacing. Post-rest potentiation was used to assess contractile reserve, and optical action potentials and calcium transients were recorded. Results: Baseline left ventricular developed pressure (LVDP), action potential duration (APD), and calcium transient duration (CaD) increased with postnatal maturation, consistent with developmental cardiomyocyte remodeling and refinement of excitation-contraction coupling. Milrinone increased heart rate in all age groups, with the greatest chronotropic response at 100 M. Milrinone also increased ventricular contractility and relaxation across developmental stages, but the magnitude of the response varied with age and was attenuated during high frequency pacing. Adult hearts had the greatest increase in LVDP during sinus rhythm and robust post-rest potentiation, which were less pronounced in neonatal hearts. APD and CaD were shortened in neonatal and adult hearts, but were minimally affected in juveniles, indicating a non-linear developmental pattern. Conclusions: Milrinone exerts positive chronotropic, inotropic, and lusitropic effects throughout development, but the magnitude and frequency dependence of these responses vary with age. These findings suggest that postnatal maturation influences the cardiac response to PDE3 inhibition. These developmental differences highlight the importance of considering age as a biological factor in pediatric drug selection and dosing.

BackgroundThe progression of abdominal aortic aneurysm (AAA) is closely associated with the phenotypic switch of vascular smooth muscle cells (VSMC). While members of the Serine/Arginine-rich splicing factor (SRs) superfamily are increasingly acknowledged for their pivotal role in modulating cell phenotype, the specific contribution of these factors to AAA development has remained underexplored. MethodsThrough integrated analyses the whole transcriptome of human and murine AAA tissues derived from clinical samples and animal models, we identified serine-arginine repeat matrix 4 (SRRM4) as a candidate gene regulating AAA formation. To investigate the role of SRRM4 in AAA formation, we used global and VSMC-specific SRRM4-knockout mice to construct AAA mouse models in two different ways. The impact of SRRM4 on AAA was further investigated in in vivo and in vitro models ResultsElevated levels of SRRM4 mRNA and protein were observed in VSMC from both human and murine AAA tissues. Targeted silencing of SRRM4 in VSMC (but not in endothelial or myeloid cells) significantly attenuated AAA formation in both AngII- and CaCl2-induced mouse models. Our results identify the RE1 silencing transcription factor (REST) as a critical target gene of SRRM4 in AAA, a master regulator of cellular phenotypic stability. We show that SRRM4 modulates VSMC phenotype through alternative splicing of the REST gene, resulting in a non-functional REST4 isoform. Furthermore, our study shows that REST directly represses STAT1, a mechanism by which SRRM4 influences VSMC phenotypic transition. Regarding clinical significance, inhibition of both STAT1 expression and function was shown to be beneficial in preventing AAA formation and slowing disease progression in mouse models. ConclusionsThis investigation uncovers a previously unrecognized role of SRRM4-mediated splicing of the REST gene in the progression of AAA and identifies a novel REST/STAT1 axis critical in the phenotypic modulation of VSMC. The findings of this study may provide insights for the development of innovative therapeutic strategies for AAA. What is New?O_LIOur study demonstrates that the RNA splicing factor SRRM4 (serine/arginine repetitive matrix 4) expression is increased in human and murine abdominal aortic aneurysm (AAA) tissues and unveils a previously undescribed role of SRRM4 in regulating AAA development. C_LIO_LISRRM4 promotes AAA development and progression through inducing splicing of REST (RE1 silencing transcription factor) gene and upregulating STAT1 (signal transducer and activator of transcription 1) expression, which result in extracellular matrix degradation, inflammation, and VSMC phenotypic switching. C_LIO_LIOur study provides proof-of-concept evidence indicating the therapeutic value of STAT1 inhibition in AAA prevention and treatment. C_LI What Are the Clinical Implications?O_LIOur study defining a novel mechanism underlying the SRRM4/REST/STAT1 axis is crucial for developing new therapeutic strategies for AAA. C_LIO_LIBased on these findings, we have initiated a prospective study (REST4-AAA; ClinicalTrials.gov Identifier: NCT07056491) to evaluate REST4 expression levels in serum of AAA patients and explore its potential as a serum biomarker for AAA prediction C_LIO_LIOur findings indicate that fludarabine, a clinically available agent reported to selectively suppress STAT1, effectively attenuates AAA progression in mice, suggesting its potential for repurposing as a therapeutic strategy for AAA. C_LI

Background Takotsubo cardiomyopathy (TTC) is a stress-induced cardiomyopathy characterized by acute cardiac dysfunction, inflammation, and hypertrophy, yet no therapy directly targets the underlying myocardial injury. Clinical studies have reported elevated circulating Angiotensin II (Ang II) levels in TTC patients, suggesting dysregulation of the renin-angiotensin system (RAS). Given the established cardioprotective effects of Angiotensin-(1-7) [Ang-(1-7)] in other cardiovascular diseases, we hypothesized that oral administration of Ang-(1-7) could attenuate acute cardiac remodeling during TTC. Methods Female C57BL/6J mice were subjected to a single high-dose isoproterenol (ISO) injection (300 mg/Kg, intraperitoneal) to induce TTC and received daily oral treatment with Ang-(1-7) complexed with hydroxypropyl {beta}-cyclodextrin [Ang-(1-7)-CD] or vehicle (CD), for 4 days, beginning one day before ISO administration. Cardiac proteome alterations were characterized by tandem mass tag (TMT)-based quantitative proteomics. Cardiac hypertrophy was assessed by heart weight normalized to tibial length and cardiomyocyte cross-sectional area. Myocardial inflammation was evaluated by histopathology, CD68 immunostaining, and flow cytometric analysis of infiltrating leukocyte populations. Results We observed a distinct cardiac proteome signature in Ang-(1-7)-treated ISO mice, predicting inhibition of pathways associated with cardiac hypertrophy and adverse remodeling. These molecular changes were accompanied by reduced heart weight normalized to tibial length and smaller cardiomyocyte cross-sectional area compared with vehicle-treated ISO mice. Oral Ang-(1-7) also attenuated myocardial inflammation, as evidenced by lower inflammatory scores, reduced CD68+ macrophage infiltration, decreased numbers of CD45+ leukocytes, and marked suppression of Ly6G+ neutrophil and CCR2+ monocyte recruitment to the heart. These protective effects were associated with improved survival following ISO challenge. MS data are available via ProteomeXchange (PXD082872). Conclusions Oral administration of Ang-(1-7) attenuated acute cardiac hypertrophy and inflammation in experimental TTC while inducing cardiac proteome changes consistent with reduced adverse remodeling. These findings identify activation of the protective RAS axis as a promising therapeutic strategy for limiting myocardial injury during TTC.

Background: Pancreatic ductal adenocarcinoma (PDAC) is projected to become the second leading cause of cancer-related mortality, with an increasing incidence and dismal 10% survival at 5 years despite best available care. PDAC is characterized by low tumour cellularity, recurrent driver mutation alterations, and substantial inter and intra-tumoural heterogeneity. The influence of individual genetic features such as sex and ancestry on tumour heterogeneity remains poorly understood. Methods: We assembled a cohort of PDAC across five datasets for a total of 7,527 tumours. Measures of genomic instability were assessed across sex and ancestry on a global level (SNV density and percent genome altered by copy number events), and at a gene level for recurrent events. KRAS variant frequencies, ploidy and mRNA abundance were also evaluated. Ancestry was assigned using ADMIXTURE from germline genotypes where available, and patient reported otherwise. Results: We observed ancestry-specific mutation patterns in global point mutation density, with higher SNV burden in African PDAC tumours and lower SNV burden in Asian PDAC tumours as compared to European tumours. We also identified an ancestry bias in the driver gene, GNAS, in which driver SNVs in GNAS was detected more frequently in those of Asian ancestry, and less frequently in those of African ancestry. No sex- or ancestry-associations were found for KRAS, but individual KRAS variants showed a trend towards ancestry-related variation. Conclusions: These findings demonstrate that ancestry contributes to the genomic heterogeneity of PDAC, shaping both global and gene-specific mutation patterns. This work underscores the importance of including diverse ancestries in PDAC molecular profiling efforts which may inform the development of tailored molecular diagnostics and targeted therapies.

{beta}-arrestins 1 and 2 are intracellular adaptor proteins that regulate the subcellular localisation and signalling of GPCRs including Parathyroid Hormone Receptor 1 (PTH1R), which produces {beta}-arrestin-dependent signalling that may selectively stimulate bone anabolism. {beta}-arrestins can themselves be regulated by post-translational modifications including phosphorylation, which dictates the translocation and signalling of the few GPCRs studied in this context to date. We aimed to investigate whether phosphorylation of {beta}-arrestins modulates their subcellular translocation in response to PTH1R activation. Translocation of {beta}-arrestins to the plasma membrane and early endosomes was quantified using BRET biosensors and immunocytochemistry with high content analysis. Phosphoknockout or phosphomimetic mutations were introduced to previously demonstrated phosphorylation sites in {beta}-arrestins 1 and 2, initially in bulk to assess overall effects. Plasma membrane translocation was altered only subtly, whereas early endosome translocation was markedly reduced for both mutations but to a greater degree for the phosphomimetic. Contributions of individual or paired sites were assessed by restoration to wildtype from the bulk phosphomimetic mutants. Dual restoration of S13 and T275 in {beta}-arrestin 1, or the analogous sites in {beta}-arrestin 2, restored the greatest degrees of early endosomal translocation, with complete restoration for {beta}-arrestin 1 and partial for {beta}-arrestin 2. Restoration of other sites had minimal or no effect. Dephosphorylation therefore appears to be required for PTH1R-stimulated {beta}-arrestin early endosomal translocation, with different phosphorylation sites implicated than some other GPCRs. These findings raise the possibility of differential {beta}-arrestin regulation by distinct stimuli which may have implications in therapeutic targeting of {beta}-arrestin-dependent pathways.

The non-canonical NF-kappa B pathway, in which NFKB2 plays a central role, is critical for lymphoid organ development and immune homeostasis. Pathogenic NFKB2 variants have been strongly associated with a broad spectrum of human pathologies, notably immunodysregulation syndromes, characterized by recurrent infections, autoantibody production and endocrine abnormalities. The mechanisms underlying the resulting immune defects remain incompletely understood. In the present study, we characterized the immune phenotype of a novel rat model harboring a Nfkb2 non-sense mutation located in the c-terminal region of the gene (c.2602T>A; p.Tyr867*, Nfkb2p.Tyr867*). This variant has been identified in patients with a familial form of common variable immunodeficiency (CVID) presenting with autoimmunity manifestations. Using this model, we demonstrate that mutated NFKB2 resulted in profound alterations of the thymic microenvironment, including reduced K5+ medullary thymic epithelial cells and decreased AIRE expression, accompanied by altered thymocyte development and impaired thymic regulatory T populations. Peripheral lymphoid organization was also profoundly affected, with absence of lymph nodes, defects in the splenic marginal zone, and alterations of CD4+ and CD8+ T-cell homeostasis, including impaired Treg populations and reduced ICOS expression on CD4+ T cells. The B-cell compartment was markedly altered, with impaired B-cell maturation, characterized by accumulation of IgM+IgD- transitional cells and a marked reduction of IgD+ mature B cells. These abnormalities were associated with impaired humoral immunity and complete absence of circulating immunoglobulins. Collectively, our findings define a systemic combined immunodeficiency phenotype in the Nfkb2-mutated rat, highlighting its utility for studying the role of non-canonical NF-kB signaling in immune system organization and adaptative immunity.

The role of aberrant glycosylation in pancreatitis remains an under-investigated area of research. Here, we determined that the ST6GAL1 sialyltransferase, which adds 2-6-linked sialic acids to N-glycoproteins, was upregulated in pancreatic tissues from patients with acute (AP) and chronic (CP) pancreatitis, and in mice with experimental AP. Within these tissues, ST6GAL1 was selectively expressed in acinar cells undergoing acinar to ductal metaplasia (ADM), a process whereby injured acinar cells de-differentiate and re-enter the cell cycle to enable tissue repair. To study the functional role of ST6GAL1 in pancreatitis, we used HPNE pancreatic epithelial cells with modulated ST6GAL1 expression, along with pancreatic organoids from mice with transgenic expression of ST6GAL1 (SC mice). In these models, ST6GAL1 activity promoted the activation of EGFR (a well-known ADM-driver), ERK, and AKT. ST6GAL1-expressing cells also displayed an ERK-dependent upregulation of the anti-apoptotic proteins, Mcl-1 and Bcl-xL, and impaired apoptotic signaling by the TNFR1 and Fas death receptors. Unbiased kinomics profiling revealed that ST6GAL1 induced the activation of many receptor tyrosine kinases associated with cell survival and proliferation (e.g., EGFR, PDGFR, MET). Furthermore, ST6GAL1 enhanced the survival and proliferation of cells exposed to stress-inducing conditions such as serum withdrawal. Based on these findings, we hypothesized that the pro-survival phenotype imparted by ST6GAL1 would facilitate tissue healing following a bout of pancreatitis. Accordingly, we induced AP in wild type and SC mice via L-arginine injection and found that SC mice had more rapid and efficient tissue repair, evidenced by accelerated restoration of the acini, diminished acinar apoptosis, and reduced immune cell infiltration. Together, these findings highlight a novel glycosylation-dependent mechanism that drives cell survival, positioning ST6GAL1 as a key adaptive mediator of pancreatic regeneration.

Background: Stroke risk is increased in cancer patients, but variations by stroke type, cancer characteristics, and treatment timing remain incompletely characterized. We investigated stroke incidence after cancer diagnosis and temporal patterns of ischemic stroke around treatments. Methods: We conducted a retrospective multicenter cohort study using linked cancer registry and administrative data from 68 cancer hospitals in Osaka, Japan. Patients diagnosed between 2019 and 2022 were followed for up to 1 year. In diagnosis-based analyses, standardized incidence ratios (SIRs) compared stroke incidence with the general population. In treatment-based analyses, ischemic stroke incidence rates and adjusted incidence rate ratios (IRRs) were estimated from 14 days before through 365 days after cancer treatments (surgery, chemotherapy, or radiotherapy). Results: Among 190,471 patients, 1660 strokes occurred: 1296 (78.0%) ischemic strokes, 315 (19.0%) intracerebral hemorrhages, and 49 (3.0%) subarachnoid hemorrhages. In diagnosis-based analyses, the overall stroke SIR was 2.13 (95% CI, 2.03?2.24), with a 1.01% 1-year cumulative incidence. SIRs were 2.37 (95% CI, 2.24?2.50), 1.72 (95% CI, 1.53?1.92), and 1.22 (95% CI, 0.91?1.62) for ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage, respectively. SIRs peaked immediately after diagnosis and declined thereafter. Excess risk persisted through 180 days for ischemic stroke, 30 days for intracerebral hemorrhage, and 7 days for subarachnoid hemorrhage. In treatment-based analyses, ischemic stroke incidence increased transiently around treatments. After surgery, the adjusted IRR peaked during days 0?7 (12.27 [95% CI, 8.50?17.71]) and remained elevated through days 31?90 versus days 181?365. A postoperative increase was observed even in early-stage disease. For chemotherapy, incidence was relatively high before treatment initiation. Conclusions: Stroke risk after cancer diagnosis varied by stroke type, cancer characteristics, and time since diagnosis. Ischemic stroke incidence increased transiently around cancer treatment, including an early postoperative increase in patients with early-stage disease. These findings identify periods and patient groups that may warrant heightened clinical vigilance.