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Loss of endothelial YAP/TAZ reduces the size of chronic stroke lesions and alters the endothelial environment
Full text linkBACKGROUND: Ischemic stroke remains a leading cause of morbidity and mortality worldwide, with limited treatment options available. Vascular dysfunction is a key pathomechanism, and brain endothelial cells (bECs) play a critical role in determining stroke outcomes. This study investigates the specific roles of YAP (yes-associated protein 1) and TAZ (WW domain containing transcription regulator 1) in regulating bEC functions during stroke. METHODS: Mice underwent 30-minute middle cerebral artery occlusion (MCAo) followed by reperfusion to model ischemic stroke. TAZ reporter mice were used to track stroke-induced subcellular changes in TAZ expression. Tamoxifen-inducible endothelial-specific Yap/Taz knockout and control mice were used to study YAP/TAZ's role in bEC function post-stroke. Stroke outcomes were measured by magnetic resonance imaging and NeuN (neuronal nuclei)-associated lesion analysis. Properties of bECs were assessed via immunohistochemistry and RNA sequencing. Inflammatory parameters were analyzed by flow cytometry of brain immune cells and quantitative polymerase chain reaction. RESULTS: Middle cerebral artery occlusion/reperfusion regulated Yap, Taz, and YAP/TAZ target gene expression in the brain. TAZ reporter mice confirmed stroke-induced endothelial YAP/TAZ activation. Endothelial-specific loss of YAP/TAZ reduced infarct volumes at 4 weeks after MCAo without impairing stroke-induced angiogenesis, revealing an unexpected neuroprotective role for endothelial YAP/TAZ depletion. YAP/TAZ deficiency modulated cGAS-STING (cyclic GMP-AMP synthase-stimulator of interferon genes) and Wnt (wingless-related integration site) signaling genes in bECs and promoted myeloid cell recruitment and an anti-inflammatory vascular environment during the subacute phase of stroke. CONCLUSIONS: Our data suggest that endothelial YAP/TAZ affects the inflammatory milieu subacutely after ischemia and thereby influences the chronic course of stroke. Modulation of YAP/TAZ activity in ECs may be a promising therapeutic target to promote neuroprotection after stroke
Chromatin spatial analysis by METALoci unveils sex-determining 3D regulatory hubs
Full text linkMammalian sex is determined by opposing networks of ovarian and testicular genes that are well characterized; however, its epigenetic regulation is still largely unknown. Here we explore the 3D chromatin landscape of sex determination in vivo by profiling fluorescence-activated cell-sorted embryonic mouse gonadal populations in both sexes before and after sex determination. Through conventional Hi-C analyses, we show that chromatin structures, particularly topologically associating domains, remain largely unchanged during sex determination, suggesting a preformed configuration. We further integrate Hi-C data with ChIP-seq experiments using METALoci, a spatial autocorrelation analysis that identifies three-dimensional (3D) regulatory hubs across the genome. We uncover a prominent rewiring of chromatin interactions during sex determination, affecting the 3D regulatory hubs of hundreds of genes that display time-specific and sex-specific expression. By combining predictive approaches and validations in transgenic mice, we identify a 3D regulatory hub for the protesticular gene Fgf9. The deletion of this gonad-specific hub allows mutant mice to survive through development, overcoming lung lethality associated with Fgf9 loss of function while exhibiting male-to-female sex reversal. Through the reconstruction of gene regulatory networks, we identify a function for Meis genes, which act redundantly to specify sexual identity during ovarian and testicular development. Our results underscore the dynamic role of the 3D genome during sex determination, highlighting the potential of epigenomic approaches to uncover regulators of developmental processes
Altered cholesterol immunometabolism activates the macrophage NLRP3-inflammasome in lung fibrosis
Full text linkPrevious research has highlighted dysregulation in lipid metabolism during lung fibrosis. However, the impact of cholesterol immunometabolism during lung fibrosis progression remains unclear but has been related to the NLRP3-inflammasome activation in cardiovascular diseases. The main objective of this work was to investigate the link between altered cholesterol metabolism and NLRP3 inflammasome activation in fibrotic lungs. Different pulmonary fibrosis patient cohorts (from 2 centers and a publicly available dataset) and a murine model of lung fibrosis (aged SP-C(–/–)) were included. Expression of cholesterol metabolism proteins and cholesterol content were determined in lungs from patients and bronchoalveolar lavage fluid (BALF) cells of aging SP-C(–/–) mice. Metabolomic and lipidomic analyses were conducted in BALF and BALF cells of SP-C(–/–) versus wild-type (WT) mice. NLRP3 inflammasome components were assessed by immunoblotting, ELISA, and immunofluorescence. Lung samples from fibrosis patients showed higher cholesterol content, altered cholesterol metabolism and higher IL-18 levels, compared to controls. Moreover, key genes related to inflammasome activation and cholesterol metabolism were differentially expressed in alveolar macrophages from IPF patients. Accordingly, BALF cells of SP-C(–/–) mice showed alteration of their cholesterol metabolism and inflammasome activation with age and fibrosis development. Lipidomic analysis pointed at cholesterol esters as potential activating agent. The molecular mechanism linking cholesterol esters to NLRP3 inflammasome and fibrosis markers was confirmed in vitro in a human macrophage model. In conclusion, altered cholesterol esterification activates the NLRP3 inflammasome in AM during pulmonary fibrosis in a murine model and fibrosis patients
Associations of genetically predicted interleukin-6 and tumor necrosis factor signaling pathways with mortality among persons with colorectal cancer: a two-sample Mendelian randomization
Full text linkBACKGROUND: Despite significant progress in identifying risk factors for colorectal cancer (CRC), factors influencing survival in people with CRC remain less understood. Pro-inflammatory cytokines like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), have been implicated in cancer progression and may influence CRC outcomes. We investigated associations between genetically predicted levels of IL-6 and TNF-α signaling pathways and mortality in people with CRC. METHODS: We conducted a two-sample Mendelian randomization (MR) analysis using cis-acting single nucleotide polymorphisms (SNPs) associated with soluble IL-6 receptor alpha (sIL6-RA) and IL-6 signal transducer gp130 (IL6ST), representing IL-6 signaling, and with TNF-α, and its soluble receptors (sTNF-R1, sTNF-R2). SNPs were obtained separately from two large genome-wide association studies (GWAS): deCODE and UK Biobank (UKB). The outcome was CRC-specific mortality among 16,964 CRC cases (4,010 deaths) in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO). Analyses were stratified by tumor site and stage. The Inverse Variance Weighted (IVW) method, incorporating a correlation matrix for dependent SNPs, was used for primary analyses. Because literature links TNF-α to CRC incidence, we additionally performed a simulation study to evaluate the potential impact of collider bias resulting from restricting analyses to CRC cases. RESULTS: Genetically predicted sIL6-RA was weakly positively associated with CRC-specific mortality (deCODE-SNPs (n=13) HR per 1 SD increase: 1.06; 95% CI: 1.00–1.12; UKB-SNPs (n=11) HR: 1.09; 95% CI: 1.02–1.17). Genetically proxied IL6ST levels showed no association with CRC-specific mortality in the overall sample (deCODE-SNPs (n=19) HR: 1.04; 95% CI: 0.90–1.21; UKB-SNPs (n=9) HR: 1.11; 95% CI: 0.87–2.42), while higher IL6ST levels were associated with increased mortality among patients with stage 2/3 disease (deCODE-SNPs (n=19) HR: 1.45; 95% CI: 1.10–1.91; UKB-SNPs (n=9) HR: 1.87; 95% CI: 1.22–2.89). No associations were observed for TNF-α, sTNF-R1, or sTNF-R2. Findings for all exposures were consistent across both GWAS datasets. Simulation analyses for TNF-α indicated collider bias was present but limited in magnitude. CONCLUSIONS: Our findings suggest that IL-6 signaling may play a role in CRC progression although of limited magnitude, whereas TNF-related pathways appear less relevant for prognosis
Patterns and trajectories of behavioral and neuropsychiatric symptoms in frontotemporal dementia and primary progressive aphasia
Full text linkBACKGROUND AND OBJECTIVES: Behavioral and neuropsychiatric symptoms are common in frontotemporal dementia (FTD) and primary progressive aphasia (PPA). However, little is known about their patterns, time course, and association with brain atrophy. We, therefore, aimed to describe behavioral and neuropsychiatric phenotypes in patients with FTD and PPA, leveraging a hypothesis-free/data-driven approach. METHODS: We included participants diagnosed with behavioral variant FTD (bvFTD) or PPA according to Rascovsky and Gorno-Tempini criteria from the German Center for Neurodegenerative Diseases Clinical Registry Study of Neurodegenerative Diseases-FTD prospective multicenter observational cohort study. Symptoms were assessed using the Neuropsychiatric Inventory-Questionnaire. Principal component analysis (PCA) was used to delineate symptom groups. Subsequently, frequency and severity across diagnostic groups were examined. We applied linear mixed-effects models to describe the longitudinal evolution of symptoms. Associations with MRI-assessed atrophy were investigated using linear regression models. RESULTS: A total of 314 patients (42.4% female, mean age 65.52 [SD 9.0] years) with bvFTD or PPA were included. MRI was available for 134 of 314 individuals. PCA revealed 4 natural symptom groups, labeled active behavioral, passive behavioral, affective, and psychotic phenotypes. Symptom groups were observed at comparable frequencies across diagnostic groups. Time from symptom onset (0.130 [0.044–0.217], p < 0.003), sex (1.376 [0.666–2.087], p < 0.001), and the interaction between the nonfluent variant of PPA and sex (−1.940 [−3.242 to −0.638], p = 0.004) showed a significant effect on the active behavioral phenotype, with symptom severity increasing over time and being most pronounced in men with bvFTD. Patients with bvFTD exhibited more severe passive behavioral symptoms compared with any other diagnostic group. For the affective phenotype, a significant interaction between time and sex (0.063 [0.010–0.117], p = 0.021) indicated a progressive increase in symptom severity in men over time. Furthermore, we found robust neuroanatomical correlations of passive behavioral symptoms with subcortical and bilateral frontal and cingulate cortical atrophy. DISCUSSION: Our findings demonstrate that behavioral and neuropsychiatric symptoms are prevalent in both bvFTD and PPA. Their severity depends on the disease duration, phenotypic group, and sex. This detailed understanding of symptomatology is crucial for optimizing patient care, diagnostic evaluations, and the design of clinical trials. Limitations comprise the lack of neuropathologic validation and the limited availability of MRI data
miRNA regulation in brain tissue space: the 3'UTR perspective
Full text linkMicroRNAs (miRNAs) are key regulators of gene expression in both health and disease. Their expression and regulatory functions are highly complex and spatiotemporally organized within tissues. In recent years, spatial transcriptomics has made significant progress in quantifying RNA expression at subcellular resolution in tissue sections. However, no current method can quantify miRNAs and their target 3′ untranslated regions (3’UTRs) in space simultaneously. Furthermore, although 3′UTRs harbor critical miRNA target sites, 3’UTR isoforms variation in space is largely unexplored. In this review, we discuss the role of miRNA-mediated regulation. We focus on neurodevelopment and neuronal function, where miRNAs and 3’UTRs have particularly complex and important functions. We summarize current experimental and computational approaches for spatial quantification of miRNAs and 3′UTRs, highlight existing challenges and propose strategies for future research
RNA-seq of cortical synaptoneurosomes from MNK1 and MNK2 KO mice
No full textThe experiment was designed to study which genes are differentially expressed on mRNA level in MNK1 or MNK2 KO mice, focusing on synaptic compartment, and further correlate these genes with mis-expressed proteins in the same genotype mice. This would reveal whether MNK1 or MNK2 KOs mostly affect transcriptional or post-transcriptional programs in the neurons
Neoadjuvant PD-1 inhibition prior to partial cryoablation of murine hepatocellular carcinoma modulates the tumor microenvironment towards favorable immunological profiles
No full textPURPOSE: To evaluate the impact of neoadjuvant systemic PD-1 immune checkpoint inhibition on the local immune response in residual tumors following partial cryoablation in a TIB-75 murine HCC model. METHODS: 48 BALB/c mice (6-12 weeks) were orthotopically implanted with TIB-75 cells to induce a single lesion of HCC. Mice were randomized into 4 treatment groups: (a) control, (b) anti-PD-1, (c) partial cryoablation, and (d) anti-PD-1 and partial cryoablation. Anti-PD-1 was administered on days 7, 9 and 11 post-inoculation, followed by partial cryoablation on day 13 and tumor harvest on day 18. The presence of T-cell subsets (CD3(+), CD4(+), CD8(+)), tumor-associated macrophages (CD68(+), CD206(+)), PD-1, and PD-L1 were assessed by histopathological analysis of immunohistochemistry. The percentage of positively stained cells within the tumor was determined using QuPath. RESULTS: Mice treated with anti-PD-1 (n=12) had greater infiltration of CD3(+), CD4(+) and CD8(+) T-cells into residual tumors than control (CD3(+): median 22.4% vs. 5.5%; p=<0.001, CD4(+): median 19.8% vs. 5.1%; p<0.001, CD8(+): median 8.2% vs. 3.1%; p=0.007). Partial cryoablation alone (n=12) increased CD206(+) M2-like macrophages (median 36.6% vs. 14.7%; p=0.03). Partial cryoablation combined with neoadjuvant anti-PD-1 (n=12) showed significantly higher infiltration of CD3(+) T-cells (median 14.3% vs. 4.5%; p=0.048) than partial cryoablation alone (n=12) and significantly lower PD-1 expression than anti-PD-1 alone (median 2.9% vs. 7.3%; p=0.004). CONCLUSION: In a mouse model of HCC, neoadjuvant PD-1 immune checkpoint inhibition can modulate the immunosuppressive tumor microenvironment observed after cryoablation. This highlights the potential of a combination therapy to treat both early- and advanced-stage HCC
Modelling cardiovascular diseases using human microphysiological systems
Full text linkDespite pharmacological-, technological- and medical- advances, cardiovascular diseases (CVDs) remain the main cause of death and disability in the world. This underscores the urgent need to better understand the early stages of these diseases for effective prevention, as well as to develop patient-specific pharmacological approaches (personalized medicine) and novel therapies. Traditional in vitro and in vivo models often fail to accurately mimic human physiology, limiting their translational potential. In this context, microphysiological systems (MPS) have emerged as advanced in vitro platforms that integrate key physiological features of cardiovascular tissues. This review summarizes the state-of-the-art advancements in in vitro models for studying CVDs, with a particular focus on emerging 3D cardiac and vascular models. These models serve as essential tools for disease modelling, drug development, and toxicity testing. Key parameters to consider when developing cardiovascular MPS are highlighted, along with a discussion of the advantages and challenges associated with each model system