Causal Role Research Articles

Low-intensity focused ultrasound to the insula differentially modulates the heartbeat-evoked potential: A proof-of-concept study

ObjectiveThe heartbeat evoked potential (HEP) is a brain response time-locked to the heartbeat and a potential marker of interoceptive processing that may be generated in the insula and dorsal anterior cingulate cortex (dACC). Low-intensity focused ultrasound (LIFU) can selectively modulate sub-regions of the insula and dACC to better understand their contributions to the HEP. MethodsHealthy participants (n = 16) received stereotaxically targeted LIFU to the anterior insula (AI), posterior insula (PI), dACC, or Sham at rest during continuous electroencephalography (EEG) and electrocardiography (ECG) recording on separate days. Primary outcome was HEP amplitudes. Relationships between LIFU pressure and HEP changes and effects of LIFU on heart rate and heart rate variability (HRV) were also explored. ResultsRelative to sham, LIFU to the PI, but not AI or dACC, decreased HEP amplitudes; PI effects were partially explained by increased LIFU pressure. LIFU did not affect heart rate or HRV. ConclusionsThese results demonstrate the ability to modulate HEP amplitudes via non-invasive targeting of key interoceptive brain regions. SignificanceOur findings have implications for the causal role of these areas in bottom-up heart-brain communication that could guide future work investigating the HEP as a marker of interoceptive processing in healthy and clinical populations.

Assessing the causal relationship between immune cells and prostatitis: evidence from bidirectional mendelian randomization analysis.

Prostatitis represents a common disease of the male genitourinary system, significantly impacting the physical and mental health of male patients. While numerous studies have suggested a potential link between immune cell activity and prostatitis, the exact causal role of immune cells in prostatitis remains uncertain. This study aims to explore the causal relationship between immune cell characteristics and prostatitis using a bidirectional Mendelian randomization approach. This study utilizes data from the public GWAS database and employs bidirectional Mendelian randomization analysis to investigate the causal relationship between immune cells and prostatitis. The causal relationship between 731 immune cell features and prostatitis was primarily investigated through inverse variance weighting (IVW), complemented by MR-Egger regression, a simple model, the weighted median method, and a weighted model. Ultimately, the results underwent sensitivity analysis to assess the heterogeneity, horizontal pleiotropy, and stability of Single Nucleotide Polymorphisms (SNPs) in immune cells and prostatitis. MR analysis revealed 17 immune cells exhibiting significant causal effects on prostatitis. In contrast, findings from reverse MR indicated a significant causal relationship between prostatitis and 13 immune cells. Our study utilizes bidirectional Mendelian Randomization to establish causal relationships between specific immune cell phenotypes and prostatitis, highlighting the reciprocal influence between immune system behavior and the disease. Our findings suggest targeted therapeutic approaches and the importance of including diverse populations for broader validation and personalized treatment strategies.

Affect and Impact Neglect in Sustainable Decision-Making

In a recent special section on Sustainability and Emotion, Schneider and van der Linden present how sustainability science could benefit from affective science to address important unanswered questions about the psychological and affective antecedents of people's engagement in relatively high-impact sustainable behaviors. Here, we underline the importance of combining the motivational role of positive affect with an impact-focused research agenda to understand the causal role of affect in sustainable decision-making and to develop communication strategies harnessing affective mechanisms to promote impactful sustainable behaviors. We present potential links connecting affective experience with perceived impact and adoption of sustainable behaviors. Finally, we argue for communication strategies aiming to enhance positive affect associated with high-impact behaviors.

Genetic evidence supporting potential causal roles of EIF4 family in breast cancer: a two-sample randomized Mendelian study

Translational control plays a crucial role in the regulation of apoptosis, with the EIF4 family serving as one of the mRNA translation factors that modulate the process of mRNA translation based on mRNA characteristics. To address this potential causal role of EIF4 family proteins and breast cancer, Mendelian randomization was employed. The study incorporated four sets of genetics instrumental variables, namely EIF4E, EIF4B, EIF4A, and EIF4EBP2. The outcome variables selected for analysis were the BCAC consortium, which included estrogen receptor positive (ER+) and estrogen receptor negative (ER−) samples. To assess the potential violations of the MR assumption, the primary MR analysis employed inverse variance weighted (IVW), and several sensitivity analyses were conducted. The findings of the two-sample MR analysis indicate that EIF4E has an adverse effect on breast cancer risk (p = 0.028). However, the evidence for the relationship between EIF4E and ER status of breast cancer suggests a weak association with ER+ breast cancer (p = 0.054), but not with ER- breast cancer (p > 0.05). The study findings indicate that EIF4A is not causally linked to the risk of ER+ breast cancer, but is significantly associated with an elevated risk of ER− breast cancer (p = 0.028). However, the evidence is inadequate to support the effects of EIF4B and EIF4EBP2 on breast cancer (p > 0.05). Our results suggest that EIF4 may be a potential factor in the occurrence and development of breast cancer, which may lead to a better understanding of its causes and prevention.

Clinical Applicability of Microbiota Sampling in a Subfertile Population: Urine versus Vagina.

The urogenital microbiota is increasingly gaining recognition as a significant contributor to reproductive health. Recent studies suggest that microbiota can serve as predictors for fertility treatment outcomes. Our objective was to investigate the degree of similarity in microbial composition between patient-collected urine and vaginal samples in a subfertile population. We enrolled women of reproductive age (20-44 years) diagnosed with subfertility and requiring in vitro fertilization (IVF) or IVF with intracytoplasmic sperm injection (IVF-ICSI) treatment. They self-collected both mid-stream urine samples and vaginal swabs before commencing the IVF or IVF-ICSI procedure. All samples were analysed using the intergenic spacer profiling (IS-pro) technique, a rapid clinical microbiota analysis tool. The main outcome measures were the degree of similarity of microbial composition between the two different, but simultaneously collected, samples. Our findings revealed a high correlation (R squared of 0.78) in microbiota profiles between paired urine and vaginal samples from individual patients. Nevertheless, the urinary microbiota profiles contained fewer species compared to the vaginal microbiota, resulting in minor but distinguishable differences. Furthermore, different subfertility diagnoses appeared to be associated with differences in microbial profiles. A noteworthy observation was the exclusive presence of Escherichia coli (E. coli) in both samples of women diagnosed with male factor subfertility. In conclusion, since urinary microbiota profiles seem to represent a diluted version of the vaginal microbiota, vaginal microbiome sampling to predict fertility treatment outcome seems preferable. To enhance the success of fertility treatments, further research is needed to gain deeper insights into a putative causal role of microbiota in the mechanisms of subfertility.

Depression and the risk of non-alcohol fatty liver disease: Results from a cross-sectional study and a Mendelian randomization analysis

BackgroundPrevious studies have suggested that psychiatric factors may be pathogenic for NAFLD. However, the association between depression and NAFLD is not been consistent, and whether depression plays a causal role in the development of NAFLD remains unclear. MethodsWe extracted data from the National Health and Nutrition Examination Survey (NHANES) 2017–2018 to assess the correlation between depression and NAFLD risk. Based on previous genome-wide association studies (GWAS) meta-analyses on NAFLD and depression, we performed a Mendelian randomization (MR) analysis to explore the causal effect of depression on NAFLD. The primary analysis method used in the MR analysis was inverse variance weighted. ResultsWe ultimately extracted the data from 3878 individuals in the NHANES database to perform the cross-sectional study. Multivariable-adjusted logistic regression showed that depressed individuals had a higher risk of NAFLD than controls (odds ratio [OR] 1.33, 95 % CI 1.03–1.72, p = 0.027) among women. Based on GWAS data, we included 36 genetic variants as instrumental variables to estimate the causal effect of depression on NAFLD risk. The MR analysis revealed a causal association between genetically predicted depression and an increased risk of NAFLD (OR = 1.504, 95 % CI 1.13–2.00, p = 0.005). LimitationsThe consistency of these findings in Eastern populations requires further longitudinal studies. ConclusionsThis cross-sectional study suggested that depression might increase the risk of NAFLD in women. The MR analysis demonstrated that there exists a causal association between genetically predicated depression and NAFLD risk.

Circulating free heme induces cytokine storm and pulmonary hypertension through the MKK3/p38 axis.

Hemolysis is associated with pulmonary hypertension (PH), but the direct contribution of circulating free heme to the PH pathogenesis remains unclear. Here, we show that the elevated levels of circulating free heme are sufficient to induce PH and inflammatory response in mice and confirm the critical role of mitogen-activated protein kinase kinase-3 (MKK3)-mediated pathway in free heme signaling. Following the continuous infusion of heme for 2 wk, wild-type (WT) but not MKK3 knockout (KO) mice develop PH, as evidenced by a significantly elevated right ventricular (RV) systolic pressure, RV hypertrophy, and pulmonary vascular remodeling. The MKK3/p38 axis, markedly activated by heme infusion in WTs, results in upregulated proliferative/cytokine signaling targets Akt, ERK1/2, and STAT3, which were abrogated in MKK3 KO mice. Moreover, the MKK3 KOs were protected against heme-mediated endothelial barrier dysfunction by restoring the tight junction protein zonula occludens-1 expression and diminishing the inflammatory cell infiltration in the lungs. Plasma cytokine multiplex analysis revealed a severe cytokine storm already 24 h after initiation of heme infusion, with a significant increase of 19 cytokines, including IL-1b, IL-2, IL-6, IL-9, and TNF-a, in WT animals and complete attenuation of cytokine production in MKK3 KO mice. Together, these findings reveal a causative role of circulating free heme in PH through activating inflammatory and proliferative responses. The central role of MKK3 in orchestrating the heme-mediated pathogenic response supports MKK3 as an attractive therapeutic target for PH and other lung inflammatory diseases linked to hemolytic anemia.NEW & NOTEWORTHY This study demonstrates that elevated levels of circulating free heme can induce pulmonary hypertension (PH) and inflammation in mice. Continuous heme infusion activated the MKK3/p38 pathway, leading to increased right ventricular pressure, right ventricular hypertrophy, and vascular remodeling. This activation upregulated signaling cascades such as Akt, ERK1/2, and STAT3, whereas MKK3 knockout mice were protected against these changes and had reduced inflammatory responses, highlighting MKK3's potential as a therapeutic target for PH.

The association between ibuprofen administration in children and the risk of developing or exacerbating asthma: a systematic review and meta-analysis

BackgroundIbuprofen is one of the most commonly used analgesic and antipyretic drugs in children. However, its potential causal role in childhood asthma pathogenesis remains uncertain. In this systematic review, we assessed the association between ibuprofen administration in children and the risk of developing or exacerbating asthma.MethodsWe searched MEDLINE, Embase, Cochrane Library, CINAHL, Web of Science, and Scopus from inception to May 2022, with no language limits; searched relevant reviews; and performed citation searching. We included studies of any design that were primary empirical peer-reviewed publications, where ibuprofen use in children 0–18 years was reported. Screening was performed in duplicate by blinded review. In total, 24 studies met our criteria. Data were extracted according to PRISMA guidelines, and the risk of bias was assessed using RoB2 and NOS tools. Quantitative data were pooled using fixed effect models, and qualitative data were pooled using narrative synthesis. Primary outcomes were asthma or asthma-like symptoms. The results were grouped according to population (general, asthmatic, and ibuprofen-hypersensitive), comparator type (active and non-active) and follow-up duration (short- and long-term).ResultsComparing ibuprofen with active comparators, there was no evidence of a higher risk associated with ibuprofen over both the short and long term in either the general or asthmatic population. Comparing ibuprofen use with no active alternative over a short-term follow-up, ibuprofen may provide protection against asthma-like symptoms in the general population when used to ease symptoms of fever or bronchiolitis. In contrast, it may cause asthma exacerbation for those with pre-existing asthma. However, in both populations, there were no clear long-term follow-up effects.ConclusionsIbuprofen use in children had no elevated risk relative to active comparators. However, use in children with asthma may lead to asthma exacerbation. The results are driven by a very small number of influential studies, and research in several key clinical contexts is limited to single studies. Both clinical trials and observational studies are needed to understand the potential role of ibuprofen in childhood asthma pathogenesis.

Testing for a causal role of thyroid hormone measurements within the normal range on human metabolism and diseases: a systematic Mendelian randomization

Variation in thyroid function parameters within the normal range has been observationally associated with adverse health outcomes. Whether those associations reflect causal effects is largely unknown. We systematically tested associations between genetic differences in thyrotropin (TSH) and free thyroxine (FT4) within the normal range and more than 1100 diseases and more than 6000 molecular traits (metabolites and proteins) in three large population-based cohorts. This was performed by combining individual and summary level genetic data and using polygenic scores and Mendelian randomization (MR) methods. We performed a phenome-wide MR study in the OpenGWAS database covering thousands of complex phenotypes and diseases. Genetically predicted TSH or FT4 levels within the normal range were predominately associated with thyroid-related outcomes, like goitre. The few extra-thyroidal outcomes that were found to be associated with genetic liability towards high but normal TSH levels included atrial fibrillation (odds ratio=0.92, p-value=2.13×10-3), thyroid cancer (odds ratio=0.57, p-value=2.97×10-4), and specific biomarkers, such as sex hormone binding globulin (β=-0.046, p-value=1.33×10-6) and total cholesterol (β=0.027, p-value=5.80×10-3). In contrast to previous studies that have described the association with thyroid hormone levels and disease outcomes, our genetic approach finds little evidence of an association between genetic differences in thyroid function within the normal range and non-thyroidal phenotypes. The association described in previous studies may be explained by reverse causation and confounding. This research was funded by the Swiss National Science Foundation (P1BEP3_200041). The Fenland study (DOI 10.22025/2017.10.101.00001) is funded by the Medical Research Council (MC_UU_12015/1, MC_PC_13046 and MC_UU_00006/1). The EPIC-Norfolk study (DOI 10.22025/2019.10.105.00004) has received funding from the Medical Research Council (MR/N003284/1, MC-UU_12015/1, MC_PC_13048 and MC_UU_00006/1).

Biological aging mediates the association between periodontitis and cardiovascular disease: results from a national population study and Mendelian randomization analysis

BackgroundThe relationship between periodontitis and cardiovascular disease (CVD) has been extensively studied, but the role of biological aging in this relationship remains poorly understood. This study is dedicated to investigating the effect of periodontitis on the incidence of CVD and to elucidating the potential mediating role of biological aging. Furthermore, this study will seek to elucidate the causal association between periodontitis, CVD, and biological aging.MethodsWe included 3269 participants from the National Health and Nutrition Examination Survey (2009–2014) with diagnostic information on periodontitis and composite CVD events. Biological aging was evaluated by utilizing both the Klemera–Doubal method’s calculated biological age (KDMAge) and phenotypic age (PhenoAge). Logistic regression, restricted cubic spline (RCS) analysis, and subgroup analysis were used for data analysis. Mediation analysis was employed to explore the mediating role of biological aging. Subsequently, Mendelian randomization (MR) analyses were performed using genome-wide association study databases to explore potential causal relationships between periodontitis, CVD, and biological aging.ResultsPeriodontitis was associated with a higher risk of CVD. Participants with periodontitis were found to have increased levels of biological aging, and elevated levels of biological aging were associated with increased CVD risk. Mediation analyses showed a partial mediating effect of biological aging (PhenoAge: 44.6%; KDMAge: 22.9%) between periodontitis and CVD risk. MR analysis showed that periodontitis played a causal role in increasing the risk of small vessel stroke, while myocardial infarction was found to increase the risk of periodontitis. In addition, reverse MR analysis showed that phenotypic aging can increase the risk of periodontitis, and there is a two-way causal relationship between CVD and biological aging.ConclusionsPeriodontitis is associated with an increased CVD risk, partially mediated by biological aging, with a complex causal interrelationship. Targeted interventions for periodontal health may slow the biological aging processes and reduce CVD risk.

Clostridium scindens : an endocrine keystone species in the mammalian gut.

Clostridium scindens is a keystone human gut microbial taxonomic group that, while low in abundance, has a disproportionate effect on bile acid and steroid metabolism in the mammalian gut. Numerous studies indicate that the two most studied strains of C. scindens (i.e., ATCC 35704 and VPI 12708) are important for a myriad of physiological processes in the host. We focus on both historical and current microbiological and molecular biology work on the Hylemon-Björkhem pathway and the steroid-17,20-desmolase pathway that were first discovered in C. scindens. Our most recent analysis now calls into question whether strains currently defined as C. scindens represent two separate taxonomic groups. Future directions include developing genetic tools to further explore the physiological role bile acid and steroid metabolism by strains of C. scindens , and the causal role of these pathways in host physiology and disease.

Small Molecule Induces Time-Dependent Inhibition of Stat3 Dimerization and DNA-Binding Activity and Regresses Human Breast Tumor Xenografts.

Aberrantly-active signal transducer and activator of transcription (Stat)3 has a causal role in many human cancers and represents a validated anticancer drug target, though it has posed significant challenge to drug development. A new small molecule, JKB887, was identified through library screening and is predicted to interact with Lys591, Arg609 and Pro63 in the phospho-tyrosine (pTyr)-binding pocket of the Stat3 SH2 domain. JKB887 inhibited Stat3 DNA-binding activity in vitro in a time-dependent manner, with IC50 of 2.2-4.5 μM at 30-60-min incubation. It directly disrupted both the Stat3 binding to the cognate, high-affinity pTyr (pY) peptide, GpYLPQTV-NH2 in fluorescent polarization assay with IC50 of 3.5-5.5 μM at 60-90-min incubation, and to the IL-6 receptor/gp130 or Src in treated malignant cells. Treatment with JKB887 selectively blocked constitutive Stat3 phosphorylation, nuclear translocation and transcriptional activity, and Stat3-regulated gene expression, and decreased viable cell numbers, cell growth, colony formation, migration, and survival in human or mouse tumor cells. By contrast, JKB887 had minimal effects on Stat1, pErk1/2MAPK, pShc, pJAK2, or pSrc induction, or on cells that do not harbor aberrantly-active Stat3. Additionally, JKB887 inhibited growth of human breast cancer xenografts in mice. JKB887 is a Stat3-selective inhibitor with demonstrable antitumor effects against Stat3-dependent human cancers.

Acute-on-chronic inflammation in acute myocardial infarction.

Acute myocardial infarction (AMI) is heralded by chronic inflammation and entails an excessive burst of acute-on-chronic inflammation (AoCI). This review describes the evolution from understanding atherosclerosis as a chronic inflammatory disease, to recent efforts in optimizing anti-inflammatory therapy to patients with AMI. It highlights the challenges and opportunities in selecting the optimal patient with AMI to derive maximal benefit from early anti-inflammatory therapy. The causal role of inflammation in atherosclerosis has been proven in large outcome trials. Since then, several smaller trials have sought to translate the concept of anti-inflammatory therapy targeting residual inflammatory risk to the dynamic early phase of AoCI after AMI. Current evidence highlights the importance of selecting patients with a high inflammatory burden. Surrogate criteria for large AMI (e.g., angiographic or electrocardiographic), as well as novel point-of-care biomarker testing may aid in selecting patients with particularly elevated AoCI. Additionally, patients presenting with AMI complicated by pro-inflammatory sequelae (e.g., atrial fibrillation, acute heart failure, left ventricular thrombosis) may dually profit from anti-inflammatory therapy. Improved understanding of the mechanisms and dynamics of acute and chronic inflammatory processes after AMI may aid the strive to optimize early anti-inflammatory therapy to patients with AMI.

Genetic association of serum calcium, phosphate, vitamin D, parathyroid hormone, and FGF23 with the risk of aortic stenosis

Disorders of mineral metabolism, including elevated levels of serum calcium, phosphate, 25-hydroxyvitamin D (25OH-VitD), parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23), have been reported in patients with calcific aortic valve stenosis (CAVS). However, evidence of the causal role of mineral metabolism in CAVS is still lacking. In this study, we employed a systematic pipeline combining Mendelian randomization (MR), Steiger directionality test, colocalization analysis, protein-protein network, and enrichment analysis to investigate the causal effect of mineral metabolism on CAVS. Genome-wide association study (GWAS) and protein quantitative trait loci data for mineral metabolism markers were extracted from large-scale meta-analyses. Summary statistics for CAVS were obtained from two independent GWAS datasets as discovery and replication cohorts (n = 374,277 and 653,867). In MR analysis, genetic mimicry of serum FGF23 elevation was associated with increased CAVS risk [ORdiscovery = 3.081 (1.649–5.760), Pdiscovery = 4.21 × 10−4; ORreplication = 2.280 (1.461 – 3.558), Preplication = 2.82 × 10−4] without evidence of reverse causation (Psteiger= 7.21 × 10−98). Strong colocalisation association with CAVS was observed for FGF23 expression in the blood (PP.H4 = 0.96). Additionally, we identified some protein-protein interactions between FGF23 and known CAVS-associated genes. Serum calcium, phosphate, 25OH-VitD, and PTH failed to show causal effects on CAVS at Bonferroni-corrected significance (all P > 0.05/5 = 0.01). In conclusion, elevated serum FGF23 level may act as a causal risk factor for CAVS, and its mechanism of action in CAVS development may be independent of its function in regulating mineral metabolism. Hence, FGF23 may serve as a circulating marker and a promising preventive target for CAVS, warranting further investigation.

Talin-1 variants associated with spontaneous coronary artery dissection (SCAD) highlight how even subtle changes in multi-functional scaffold proteins can manifest in disease.

Variants of talin-1 (TLN1) have recently been linked with spontaneous coronary artery dissection (SCAD) a condition where a tear can form in the wall of a heart artery necessitating immediate medical care. One talin-1 variant, A2013T, has an extensive familial pedigree of SCAD, which led to the screening for, and identification of, further talin-1 variants in SCAD patients. Here we evaluated these variants with commonly used pathogenicity prediction tools and found it challenging to reliably classify SCAD-associated variants, even A2013T where the evidence of a causal role is strong. Using biochemical and cell biological methods, we show that SCAD-associated variants in talin-1, which would typically be classified as non-pathogenic, still cause a measurable impact on protein structure and cell behaviour, including cell movement and wound healing capacity. Together, this indicates that even subtle variants in central mechanosensitive adapter proteins, can give rise to significant health impacts at the individual level, suggesting the need for a possible re-evaluation of the scoring criteria for pathogenicity prediction for talin variants.

The Causal Effect of Intrapancreatic Fat Deposition on Acute and Chronic Pancreatitis: A Mendelian Randomization Study.

Recent associative studies have linked intrapancreatic fat deposition (IPFD) with risk of pancreatitis, but the causal relationship remains unclear. Using Mendelian randomization, we evaluated the causal association between genetically predicted IPFD and pancreatitis. This approach used genetic variants from genomewide association studies of IPFD (n = 25,617), acute pancreatitis (n = 6,787 cases/361,641 controls), and chronic pancreatitis (n = 3,875 cases/361,641 controls). Genetically predicted IPFD was significantly associated with acute pancreatitis (odds ratio per 1-SD increase: 1.40 [95% CI: 1.12-1.76], P = 0.0032) and chronic pancreatitis (odds ratio: 1.64 [95% CI: 1.13-2.39], P = 0.0097). Our findings support a causal role of IPFD in pancreatitis, suggesting that reducing IPFD could lower the risk of pancreatitis.

Low hemoglobin causes hematoma expansion and poor intracerebral hemorrhage outcomes.

Although lower hemoglobin levels associate with worse intracerebral hemorrhage (ICH) outcomes, causal drivers for this relationship remain unclear. We investigated the hypothesis that lower hemoglobin relates to increased hematoma expansion (HE) risk and poor outcomes using human observational data and assessed causal relationships using a translational murine model of anemia and ICH. ICH patients with baseline hemoglobin measurements and serial CT neuroimaging enrolled between 2010-2016 to a multicenter, prospective observational cohort study were studied. Patients with systemic evidence of coagulopathy were excluded. Separate regression models assessed relationships of baseline hemoglobin with HE (≥33% and/or ≥6mL growth) and poor long-term neurological outcomes (modified Rankin Scale 4-6) after adjusting for relevant covariates. Using a murine collagenase ICH model with serial neuroimaging in anemic vs. non-anemic C57/BL6 mice, intergroup differences in ICH lesion volume, ICH volume changes, and early mortality were assessed. Among 1190 ICH patients analyzed, lower baseline hemoglobin levels associated with increased odds of HE (adjusted OR per -1g/dL hemoglobin decrement: 1.10 [1.02-1.19]) and poor 3-month clinical outcomes (adjusted OR per -1g/dL hemoglobin decrement: 1.11 [1.03-1.21]). Similar relationships were seen with poor 6 and 12-month outcomes. In our animal model, anemic mice had significantly greater ICH lesion expansion, final lesion volumes, and greater mortality, as compared to non-anemic mice. These results, in a human cohort and a mouse model, provide novel evidence suggesting that anemia has causal roles in HE and poor ICH outcomes. Additional studies are required to clarify whether correcting anemia can improve these outcomes.

Artificially inserted strong promoter containing multiple G-quadruplexes induces long-range chromatin modification.

Although the role of G-quadruplex (G4) DNA structures has been suggested in chromosomal looping this was not tested directly. Here, to test causal function, an array of G4s, or control sequence that does not form G4s, were inserted within chromatin in cells. In vivo G4 formation of the inserted G4 sequence array, and not the control sequence, was confirmed using G4-selective antibody. Compared to the control insert, we observed a remarkable increase in the number of 3D chromatin looping interactions from the inserted G4 array. This was evident within the immediate topologically associated domain (TAD) and throughout the genome. Locally, recruitment of enhancer histone marks and the transcriptional coactivator p300/Acetylated-p300 increased in the G4-array, but not in the control insertion. Resulting promoter-enhancer interactions and gene activation were clear up to 5 Mb away from the insertion site. Together, these show the causal role of G4s in enhancer function and long-range chromatin interactions. Mechanisms of 3D topology are primarily based on DNA-bound architectural proteins that induce/stabilize long-range interactions. Involvement of the underlying intrinsic DNA sequence/structure in 3D looping shown here therefore throws new light on how long-range chromosomal interactions might be induced or maintained.

Genetic overlap and Mendelian randomization analysis highlighted the causal relationship between psoriatic disease and migraine.

Despite observational studies suggesting a link between psoriatic disease (including psoriasis and psoriatic arthritis) and migraine, it is unclear whether there is a shared genetic etiology or a causal relationship between the two conditions. We aimed to reveal the genetic overlap and causality using the Mendelian randomization (MR) framework. The genetic analysis utilized summary data from the most extensive European genome-wide association study (GWAS) of migraine. Well-powered psoriatic disease GWAS data were obtained from two independent cohort studies, which served as discovery and validation datasets. Global and regional genetic correlations between psoriatic disease and migraine were assessed, and pleiotropic regions identified by pairwise GWAS analysis were further annotated. We further applied a two-sample MR multivariate MR to investigate the potential causal relationship between them. The global genetic correlation test indicated weak correlations between psoriatic disease and migraine, while regional correlation analyses delineated one significant shared locus between psoriasis and migraine. Pathway enrichment analysis revealed that shared genes were involved biological processes to the major histocompatibility and antigen processing and presentation. In terms of causality estimates, genetically predicted psoriasis (Pmeta = 0.003) and psoriatic arthritis (Pmeta = 0.028) were associated with an increased risk of migraine. Multivariate MR analysis indicated that psoriasis was an independent risk factor for migraine (P < 0.05). No significant associations were found in the reverse direction. Our study supported the causal role of psoriasis on migraine, and the central role for immunomodulatory etiology. These findings have significant implications for the management of migraine and clinical practice in patients with psoriasis.

Artificially inserted strong promoter containing multiple G-quadruplexes induces long-range chromatin modification

Although the role of G-quadruplex (G4) DNA structures has been suggested in chromosomal looping this was not tested directly. Here, to test causal function, an array of G4s, or control sequence that does not form G4s, were inserted within chromatin in cells. In vivo G4 formation of the inserted G4 sequence array, and not the control sequence, was confirmed using G4-selective antibody. Compared to the control insert, we observed a remarkable increase in the number of 3D chromatin looping interactions from the inserted G4 array. This was evident within the immediate topologically associated domain (TAD) and throughout the genome. Locally, recruitment of enhancer histone marks and the transcriptional coactivator p300/Acetylated-p300 increased in the G4-array, but not in the control insertion. Resulting promoter-enhancer interactions and gene activation were clear up to 5 Mb away from the insertion site. Together, these show the causal role of G4s in enhancer function and long-range chromatin interactions. Mechanisms of 3D topology are primarily based on DNA-bound architectural proteins that induce/stabilize long-range interactions. Involvement of the underlying intrinsic DNA sequence/structure in 3D looping shown here therefore throws new light on how long-range chromosomal interactions might be induced or maintained.