Human Y Chromosome Exerts Pleiotropic Effects on Susceptibility to Atherosclerosis

Multiple origins and phenotypic implications of an extended human pseudoautosomal region shown by analysis of the UK Biobank

The 2.7-Mb major pseudoautosomal region (PAR1) on the short arms of the human X and Y chromosomes plays a critical role in meiotic sex chromosome segregation and male fertility and has been regarded as evolutionarily stable. However, some European Y chromosomes belonging to Y haplogroups (Y-Hgs) R1b and I2a carry an ∼115-kb extension (ePAR [extended PAR]) arising from X-Y non-allelic homologous recombination (NAHR). To investigate the diversity, history, and dynamics of ePAR formation, we screened for its presence, and that of the predicted reciprocal X chromosome deletion, among ∼218,300 46,XY males of the UK Biobank (UKB), a cohort associated with longitudinal clinical data. The UKB incidence of ePAR is ∼0.77%, and that of the deletion is ∼0.02%. We found that Y-Hg I2a sub-lineages accounted for nearly 90% of ePAR cases but, by Y haplotyping and breakpoint sequencing, determined that, in total, there have been at least 18 independent ePAR origins, associated with nine different Y-Hgs. We found examples of ePAR linked to Y-Hg K among men of self-declared Pakistani ancestry and Y-Hg E1, typical of men with African ancestry, showing that ePAR is not restricted to Europeans. ePAR formation is likely random, with high frequencies in some Y-Hgs arising through drift and male-mediated expansions. Sequencing recombination junction fragments identified likely reciprocal events, and the heterogeneity of ePAR and X-deletion junctions highlighted the recurrent nature of the NAHR events. A phenome-wide association study revealed an association between ePAR and elevated levels of circulating IGF-1 as well as musculoskeletal phenotypes.

Sexual dimorphism in aortic aneurysm: A review of the contributions of sex hormones and sex chromosomes

Aortic aneurysm is a common cardiovascular disease. Over time, the disease damages the structural and functional integrity of the aorta, causing it to abnormally expand and potentially rupture, which can be fatal. Sex differences are evident in the disease, with men experiencing an earlier onset and higher incidence. However, women may face a worse prognosis and a higher risk of rupture. While there are some studies on the cellular and molecular mechanisms of aneurysm formation, it remains unclear how sex factors contribute to sexual dimorphism. Therefore, this review aims to summarize the role of sex in the occurrence of aortic aneurysms, offering valuable insights for disease prevention and the development of appropriate treatment options.

Sex differences in disease: sex chromosome and immunity

Sex is a fundamental biological variable that influences immune system function, with sex chromosomes (X and Y) playing a central role in these differences. Despite substantial evidence of disparities in immune responses between males and females, biomedical research has historically overlooked sex as a critical factor. This oversight has contributed to the observed disparities in susceptibility to autoimmune diseases, infectious diseases, and malignancies between the sexes. In this review, we address the phenomena and mechanisms through which aberrant expression of sex chromosome-linked genes contributes to sex-based differences in immune responses. We specifically focus on the implications of X chromosome inactivation (XCI) escape and loss of Y chromosome (LOY). Our review aims to elucidate the molecular mechanisms driving these sex-based differences, with particular emphasis on the interactions between sex chromosome genes and immune cells in both males and females. Additionally, we discuss the potential impact of these differences on disease susceptibility and identify prospective therapeutic targets. As personalized and precision medicine advances, it is crucial to integrate sex differences into immunological research and clinical trials. We advocate for an increased focus on sex-based considerations in fundamental, translational, and clinical research to promote personalized, sex-specific healthcare.

Genetics of hypertension-related sex differences and hypertensive disorders of pregnancy

Background: Hypertension and hypertensive disorders of pregnancy (HDP) cause a significant burden of disease on societies and individuals by increasing cardiovascular disease risk. Environmental risk factors alone do not explain the observed sexual dimorphism in lifetime blood pressure (BP) trajectories nor inter-individual variation in HDP risk.

Methods: In this short review, we focus on the genetics of hypertension-related sex differences and HDP and discuss the importance of genetics utilization for sex-specific hypertension risk prediction.

Results: Population and twin studies estimate that 28-66% of variation in BP levels and HDP is explained by genetic variation, while genomic wide association studies suggest that BP traits and HDP partly share a common genetic background. Moreover, environmental and epigenetic regulation of these genes differ by sex and oestrogen receptors in particular are shown to convey cardio- and vasculoprotective effects through epigenetic regulation of DNA. The majority of known genetic variation in hypertension and HDP is polygenic. Polygenic risk scores for BP display stronger associations with hypertension risk in women than in men and are associated with sex-specific age of hypertension onset. Monogenic forms of hypertension are rare and mostly present equally in both sexes.

Conclusion: Despite recent genetic discoveries providing new insights into HDP and sex differences in BP traits, further research is needed to elucidate the underlying biology. Emphasis should be placed on demonstrating the added clinical value of these genetic discoveries, which may eventually facilitate genomics-based personalized treatments for hypertension and HDP.

Sex Differences in Cardiovascular Diseases: Exploring the Role of Microbiota and Immunity

Cardiovascular diseases (CVDs) are the most common cause of mortality and morbidity in Western countries, thus representing a global health concern. CVDs show different patterns in terms of the prevalence and presentation in men and women. The role of sex hormones has been extensively implicated in these sex-specific differences, due to the presence of the menstrual cycle and menopause in women. Moreover, the gut microbiota (GM) has been implicated in cardiovascular health, considering the growing evidence that it is involved in determining the development of specific diseases. In particular, gut-derived metabolites have been linked to CVDs and kidney disorders, which can in turn promote the progression of CVDs. Considering the differences in the composition of GM between men and women, it is possible that gut microbiota act as a mediator in regard to the sex disparities in CVDs. This narrative review aims to comprehensively review the interplay between sex, GM, and CVDs, discussing potential mechanisms and therapeutic options.

Chromosome-Y haplogroups in Asturias (Northern Spain) and their association with severe COVID-19

The main objective of this study was to determine whether the common Y-haplogroups were be associated with the risk of developing severe COVID-19 in Spanish male. We studied 479 patients who required hospitalization due to COVID-19 and 285 population controls from the region of Asturias (northern Spain), They were genotyped for several polymorphisms that define the common European Y-haplogroups. We compared the frequencies between patients and controls aged ≤ 65 and >65 years. There were no different haplogroup frequencies between the two age groups of controls. Haplogroup R1b was less common in patients aged ≤65 years. Haplogroup I was more common in the two patient´s groups compared to controls (p = 0.02). Haplogroup R1b was significantly more frequent among hypertensive patients, without difference between the hypertensive and normotensive controls. This suggested that R1b could increase the risk for severe COVID-19 among male with pre-existing hypertension. In conclusion, we described the Y-haplogroup structure among Asturians. We found an increased risk of severe COVID-19 among haplogroup I carriers, and a significantly higher frequency of R1b among hypertensive patients. These results indicate that Y-chromosome variants could serve as markers to define the risk of developing a severe form of COVID-19.

Atherosclerosis as the Damocles' sword of human evolution: insights from nonhuman ape-like primates, ancient human remains, and isolated modern human populations

Atherosclerosis is the leading cause of death worldwide, and the predominant risk factors are advanced age and high-circulating low-density lipoprotein cholesterol (LDL-C). However, the findings of atherosclerosis in relatively young mummified remains and a lack of atherosclerosis in chimpanzees despite high LDL-C call into question the role of traditional cardiovascular risk factors. The inflammatory theory of atherosclerosis may explain the discrepancies between traditional risk factors and observed phenomena in current literature. Following the divergence from chimpanzees several millennia ago, loss of function mutations in immune regulatory genes and changes in gene expression have resulted in an overactive human immune system. The ubiquity of atherosclerosis in the modern era may reflect a selective pressure that enhanced the innate immune response at the cost of atherogenesis and other chronic disease states. Evidence provided from the fields of genetics, evolutionary biology, and paleoanthropology demonstrates a sort of circular dependency between inflammation, immune system functioning, and evolution at both a species and cellular level. More recently, the role of proinflammatory stimuli, somatic mutations, and the gene-environment effect appear to be underappreciated elements in the development and progression of atherosclerosis. Neurobiological stress, metabolic syndrome, and traditional cardiovascular risk factors may instead function as intermediary links between inflammation and atherosclerosis. Therefore, considering evolution as a mechanistic process and atherosclerosis as part of the inertia of evolution, greater insight into future preventative and therapeutic interventions for atherosclerosis can be gained by examining the past.

Developmental transcriptomic patterns can be altered by transgenic overexpression of Uty

The genetic material encoded on X and Y chromosomes provides the foundation by which biological sex differences are established. Epigenetic regulators expressed on these sex chromosomes, including Kdm6a (Utx), Kdm5c, and Ddx3x have far-reaching impacts on transcriptional control of phenotypic sex differences. Although the functionality of UTY (Kdm6c, the Y-linked homologue of UTX), has been supported by more recent studies, its role in developmental sex differences is not understood. Here we test the hypothesis that UTY is an important transcriptional regulator during development that could contribute to sex-specific phenotypes and disease risks across the lifespan. We generated a random insertion Uty transgenic mouse (Uty-Tg) to overexpress Uty. By comparing transcriptomic profiles in developmental tissues, placenta and hypothalamus, we assessed potential UTY functional activity, comparing Uty-expressing female mice (XX + Uty) with wild-type male (XY) and female (XX) mice. To determine if Uty expression altered physiological or behavioral outcomes, adult mice were phenotypically examined. Uty expression masculinized female gene expression patterns in both the placenta and hypothalamus. Gene ontology (GO) and gene set enrichment analysis (GSEA) consistently identified pathways including immune and synaptic signaling as biological processes associated with UTY. Interestingly, adult females expressing Uty gained less weight and had a greater glucose tolerance compared to wild-type male and female mice when provided a high-fat diet. Utilizing a Uty-overexpressing transgenic mouse, our results provide novel evidence as to a functional transcriptional role for UTY in developing tissues, and a foundation to build on its prospective capacity to influence sex-specific developmental and health outcomes.

Factors Influencing Functional Coronary Artery Ischemia: A Gender-Specific Predictive Model

Objective

The objective of this study was to explore factors that impact functional coronary artery ischemia (FCAI) and develop a gender-specific prognostic model that could serve as a benchmark for predicting FCAI in clinical practice.

Methods

A cumulative total of 330 patients were enrolled comprising 634 main and branch coronary, consisting of 179 men (359 coronary arteries) and 151 women (275 coronary arteries). Based on the computed tomography-fractional flow reserve (CT-FFR), the coronary arteries of male and female patients were classified into the non-ischemic group (CT-FFR ≥ 0.80) and the ischemic group (CT-FFR < 0.80). We screened for factors related to the CT-FFR values of the coronary arteries in male and female patients and developed corresponding gender-specific models.

Results

In male patients, the correlation between FCAI and several indicators, including white blood cell (WBC) count, left anterior descending artery (LAD) lesions, pericoronary fat attenuation index (FAI), and the degree of coronary artery stenosis, was found to be statistically significant. A predictive model was developed using these factors, yielding an area under the curve (AUC) value of 0.812, with a P value of < 0.001 and a 95% confidence interval (CI) ranging from 0.767 to 0.857. This model demonstrated superior predictive capability compared to any individual indicators mentioned above. Significant correlations with FCAI were observed in female patients for hemoglobin (Hb), systolic blood pressure (SBP), FAI, and the degree of coronary artery stenosis. The predictive model, derived from these factors, exhibited robust performance with an area under the curve (AUC) value of 0.818, a P value of < 0.001, and a 95% confidence interval (CI) ranging from 0.764 to 0.872.

Conclusion

Gender disparities exist in the factors affecting FCAI, underscoring the need for a gender-specific predictive model to enhance the precision of FCAI prediction.

Gonadal sex vs genetic sex in experimental atherosclerosis

Epidemiological data and interventional studies with hormone replacement therapy suggest that women, at least until menopause, are at decreased cardiovascular risk compared to men. Still the molecular mechanisms beyond this difference are debated and the investigation in experimental models of atherosclerosis has been pivotal to prove that the activation of the estrogen receptor is atheroprotective, despite not enough to explain the differences reported in cardiovascular disease between male and female. This casts also for investigating the importance of the sex chromosome complement (genetic sex) beyond the contribution of sex hormones (gonadal sex) on atherosclerosis. Aim of this review is to present the dualism between gonadal sex and genetic sex with a focus on the data available from experimental models. The molecular mechanisms driving changes in lipid metabolism, immuno-inflammatory reactivity and vascular response in males and females that affect atherosclerosis progression will be discussed.

The impact of chromosomal sex on cardiometabolic health and disease

Many aspects of metabolism are sex-biased, from gene expression in metabolic tissues to the prevalence and presentation of cardiometabolic diseases. The influence of hormones produced by male and female gonads has been widely documented, but recent studies have begun to elucidate the impact of genetic sex (XX or XY chromosomes) on cellular and organismal metabolism. XX and XY cells have differential gene dosage conferred by specific genes that escape X chromosome inactivation or the presence of Y chromosome genes that are absent from XX cells. Studies in mouse models that dissociate chromosomal and gonadal sex have uncovered mechanisms for sex-biased epigenetic, transcriptional, and post-transcriptional regulation of gene expression in conditions such as obesity, atherosclerosis, pulmonary hypertension, autoimmune disease, and Alzheimer's disease.

Y Chromosome Genomic Variations and Biological Significance in Human Diseases and Health

The Y chromosome is a haploid genome unique to males with no genes essential for life. It is easily transmitted to the next generation without being repaired by recombination, even if a major genomic structural alteration occurs. On the other hand, the Y chromosome genome is basically a region transmitted only from father to son, reflecting a male-specific inheritance between generations. The Y chromosome exhibits genomic structural differences among different ethnic groups and individuals. The Y chromosome was previously thought to affect only male-specific phenotypes, but recent studies have revealed associations between the Y chromosomes and phenotypes common to both males and females, such as certain types of cancer and neuropsychiatric disorders. This evidence was discovered with the finding of the mosaic loss of the Y chromosome in somatic cells. This phenomenon is also affected by environmental factors, such as smoking and aging. In the past, functional analysis of the Y chromosome has been elucidated by assessing the function of Y chromosome-specific genes and the association between Y chromosome haplogroups and human phenotypes. These studies are currently being conducted intensively. Additionally, the recent advance of large-scale genome cohort studies has increased the amount of Y chromosome genomic information available for analysis, making it possible to conduct more precise studies of the relationship between genome structures and phenotypes. In this review, we will introduce recent analyses using large-scale genome cohort data and previously reported association studies between Y chromosome haplogroups and human phenotypes, such as male infertility, cancer, cardiovascular system traits, and neuropsychiatric disorders. The function and biological role of the Y chromosome in human phenotypes will also be discussed.

Circulating macrophages as the mechanistic link between mosaic loss of Y-chromosome and cardiac disease

BACKGROUND

Genetics evidences have long linked mosaic loss of Y-chromosome (mLOY) in peripheral leukocytes with a wide range of male age-associated diseases. However, a lack of cellular and molecular mechanistic explanations for this link has limited further investigation into the relationship between mLOY and male age-related disease. Excitingly, Sano et al. have provided the first piece of evidence directly linking mLOY to cardiac fibrosis through mLOY enriched profibrotic transforming growth factor β1 (TGF-β1) regulons in hematopoietic macrophages along with suppressed interleukin-1β (IL-1β) proinflammatory regulons. The results of this novel finding can be extrapolated to other disease related to mLOY, such as cancer, cardiac disease, and age-related macular degeneration.

RESULTS

Sano et al. used a CRISPR-Cas9 gRNAs gene editing induced Y-chromosome ablation mouse model to assess results of a UK biobank prospective analysis implicating the Y-chromosome in male age-related disease. Using this in vivo model, Sano et al. showed that hematopoietic mLOY accelerated cardiac fibrosis and heart failure in male mice through profibrotic pathways. This process was linked to monocyte-macrophage differentiation during hematopoietic development. Mice confirmed to have mLOY in leukocytes, by loss of Y-chromosome genes Kdm5d, Uty, Eif2s3y, and Ddx3y, at similar percentages to the human population were shown to have accelerated rates of interstitial and perivascular fibrosis and abnormal echocardiograms. These mice also recovered poorly from the transverse aortic constriction (TAC) model of heart failure and developed left ventricular dysfunction at higher rates. This was attributed to aberrant proliferation of cardiac MEF-SK4 + fibroblasts promoted by mLOY macrophages enriched in profibrotic regulons and lacking in proinflammatory regulons. These pro-fibrotic macrophages localized to heart and eventually resulted in cardiac fibrosis via enhanced TGF-β1 and suppressed IL-1β signaling. Furthermore, treatment of mLOY mice with TGFβ1 neutralizing antibody was able to improve their cardiac function. This study by Sano et al. was able to provide a causative link between the known association between mLOY and male cardiac disease morbidity and mortality for the first time, and thereby provide a new target for improving human health.

CONCLUSIONS

Using a CRISPR-Cas9 induced Y-chromosome ablation mouse model, Sano et al. has proven mosaic loss of Y-chromosome in peripheral myeloid cells to have a causative effect on male mobility and mortality due to male age-related cardiac disease. They traced the mechanism of this effect to hyper-expression of the profibrotic TGF-β1 and reduced pro-inflammatory IL-1β signaling, attenuation of which could provide another potential strategy in improving outcomes against age-related diseases in men.

Chromosome Y Haplogroup R Was Associated with the Risk of Premature Myocardial Infarction with ST-Elevation: Data from the CholeSTEMI Registry

Cardiovascular disease (CVD) is the leading cause of death worldwide, with coronary artery disease (CAD) being one of its main manifestations. Both environmental and genetic factors are widely known to be related to CAD, such as smoking, diabetes mellitus, dyslipidemia, and a family history of CAD. However, there is still a lack of information about other risk factors, especially those related to genetic mutations. Sex represents a classic CAD risk factor, as men are more likely to suffer CAD, but there is lack of evidence with regard to sex-specific genetic factors. We evaluated the Y chromosome haplogroups in a cohort of young Spanish male patients who suffered from STEMI. In this cohort, haplogroup R was significantly more frequent in STEMI patients.

Identification of the susceptible genes and mechanism underlying the comorbid presence of coronary artery disease and rheumatoid arthritis: a network modularization analysis

OBJECTIVE

The comorbidities of coronary artery disease (CAD) and rheumatoid arthritis (RA) are mutual risk factors, which lead to higher mortality, but the biological mechanisms connecting the two remain unclear. Here, we aimed to identify the risk genes for the comorbid presence of these two complex diseases using a network modularization approach, to offer insights into clinical therapy and drug development for these diseases.

METHOD

The expression profile data of patients CAD with and without RA were obtained from the GEO database (GSE110008). Based on the differentially expressed genes (DEGs), weighted gene co-expression network analysis (WGCNA) was used to construct a gene network, detect co-expression modules, and explore their relation to clinical traits. The Zsummary index, gene significance (GS), and module membership (MM) were utilized to screen the important differentiated modules and hub genes. The GO and KEGG pathway enrichment analysis were applied to analyze potential mechanisms.

RESULT

Based on the 278 DEGs obtained, 41 modules were identified, of which 17 and 24 modules were positively and negatively correlated with the comorbid occurrence of CAD and RA (CAD&RA), respectively. Thirteen modules with Zsummary < 2 were found to be the underlying modules, which may be related to CAD&RA. With GS ≥ 0.5 and MM ≥ 0.8, 49 hub genes were identified, such as ADO, ABCA11P, POT1, ZNF141, GPATCH8, ATF6 and MIA3, etc. The area under the curve values of the representative seven hub genes under the three models (LR, KNN, SVM) were greater than 0.88. Enrichment analysis revealed that the biological functions of the targeted modules were mainly involved in cAMP-dependent protein kinase activity, demethylase activity, regulation of calcium ion import, positive regulation of tyrosine, phosphorylation of STAT protein, and tissue migration, etc. CONCLUSION: Thirteen characteristic modules and 49 susceptibility hub genes were identified, and their corresponding molecular functions may reflect the underlying mechanism of CAD&RA, hence providing insights into the development of clinical therapies against these diseases.

Molecular models of multiple sclerosis severity identify heterogeneity of pathogenic mechanisms

While autopsy studies identify many abnormalities in the central nervous system (CNS) of subjects dying with neurological diseases, without their quantification in living subjects across the lifespan, pathogenic processes cannot be differentiated from epiphenomena. Using machine learning (ML), we searched for likely pathogenic mechanisms of multiple sclerosis (MS). We aggregated cerebrospinal fluid (CSF) biomarkers from 1305 proteins, measured blindly in the training dataset of untreated MS patients (N = 129), into models that predict past and future speed of disability accumulation across all MS phenotypes. Healthy volunteers (N = 24) data differentiated natural aging and sex effects from MS-related mechanisms. Resulting models, validated (Rho 0.40-0.51, p < 0.0001) in an independent longitudinal cohort (N = 98), uncovered intra-individual molecular heterogeneity. While candidate pathogenic processes must be validated in successful clinical trials, measuring them in living people will enable screening drugs for desired pharmacodynamic effects. This will facilitate drug development making, it hopefully more efficient and successful.

Contributions of obesity to kidney health and disease: insights from Mendelian randomization and the human kidney transcriptomics

AIMS

Obesity and kidney diseases are common complex disorders with an increasing clinical and economic impact on healthcare around the globe. Our objective was to examine if modifiable anthropometric obesity indices show putatively causal association with kidney health and disease and highlight biological mechanisms of potential relevance to the association between obesity and the kidney.

METHODS AND RESULTS

We performed observational, one-sample, two-sample Mendelian randomization (MR) and multivariable MR studies in ∼300 000 participants of white-British ancestry from UK Biobank and participants of predominantly European ancestry from genome-wide association studies. The MR analyses revealed that increasing values of genetically predicted body mass index and waist circumference were causally associated with biochemical indices of renal function, kidney health index (a composite renal outcome derived from blood biochemistry, urine analysis, and International Classification of Disease-based kidney disease diagnoses), and both acute and chronic kidney diseases of different aetiologies including hypertensive renal disease and diabetic nephropathy. Approximately 13-16% and 21-26% of the potentially causal effect of obesity indices on kidney health were mediated by blood pressure and type 2 diabetes, respectively. A total of 61 pathways mapping primarily onto transcriptional/translational regulation, innate and adaptive immunity, and extracellular matrix and metabolism were associated with obesity measures in gene set enrichment analysis in up to 467 kidney transcriptomes.

CONCLUSIONS

Our data show that a putatively causal association of obesity with renal health is largely independent of blood pressure and type 2 diabetes and uncover the signatures of obesity on the transcriptome of human kidney.

Analysis of Y chromosome haplogroups in Parkinson's disease

Parkinson's disease is a complex neurodegenerative disorder that is about 1.5 times more prevalent in males than females. Extensive work has been done to identify the genetic risk factors behind Parkinson's disease on autosomes and more recently on Chromosome X, but work remains to be done on the male-specific Y chromosome. In an effort to explore the role of the Y chromosome in Parkinson's disease, we analysed whole-genome sequencing data from the Accelerating Medicines Partnership-Parkinson's disease initiative (1466 cases and 1664 controls), genotype data from NeuroX (3491 cases and 3232 controls) and genotype data from UKBiobank (182 517 controls, 1892 cases and 3783 proxy cases), all consisting of male European ancestry samples. We classified sample Y chromosomes by haplogroup using three different tools for comparison (Snappy, Yhaplo and Y-LineageTracker) and meta-analysed this data to identify haplogroups associated with Parkinson's disease. This was followed up with a Y-chromosome association study to identify specific variants associated with disease. We also analysed blood-based RNASeq data obtained from the Accelerating Medicines Partnership-Parkinson's disease initiative (1020 samples) and RNASeq data obtained from the North American Brain Expression Consortium (171 samples) to identify Y-chromosome genes differentially expressed in cases, controls, specific haplogroups and specific tissues. RNASeq analyses suggest Y-chromosome gene expression differs between brain and blood tissues but does not differ significantly in cases, controls or specific haplogroups. Overall, we did not find any strong associations between Y-chromosome genetics and Parkinson's disease, suggesting the explanation for the increased prevalence in males may lie elsewhere.

Limited Effect of Y Chromosome Variation on Coronary Artery Disease and Mortality in UK Biobank-Brief Report

BACKGROUND

The effect of genetic variation in the male-specific region of the Y chromosome (MSY) on coronary artery disease and cardiovascular risk factors has been disputed. In this study, we systematically assessed the association of MSY genetic variation on these traits using a kin-cohort analysis of family disease history in the largest sample to date.

METHODS

We tested 90 MSY haplogroups against coronary artery disease, hypertension, blood pressure, classical lipid levels, and all-cause mortality in up to 152 186 unrelated, genomically British individuals from UK Biobank. Unlike previous studies, we did not adjust for heritable lifestyle factors (to avoid collider bias) and instead adjusted for geographic variables and socioeconomic deprivation, given the link between MSY haplogroups and geography. For family history traits, subject MSY haplogroups were tested against father and mother disease as validation and negative control, respectively.

RESULTS

Our models find little evidence for an effect of any MSY haplogroup on cardiovascular risk in participants. Parental models confirm these findings.

CONCLUSIONS

Kin-cohort analysis of the Y chromosome uniquely allows for discoveries in subjects to be validated using family history data. Despite our large sample size, improved models, and parental validation, there is little evidence to suggest cardiovascular risk in UK Biobank is influenced by genetic variation in MSY.

Y-Chromosome Gene, Uty, Protects Against Pulmonary Hypertension by Reducing Proinflammatory Chemokines

Rationale: Idiopathic pulmonary arterial hypertension (PAH) is a terminal pulmonary vascular disease characterized by increased pressure, right ventricular failure, and death. PAH exhibits a striking sex bias and is up to four times more prevalent in females. Understanding the molecular basis behind sex differences could help uncover novel therapies. Objectives: We previously discovered that the Y chromosome is protective against hypoxia-induced experimental pulmonary hypertension (PH), which may contribute to sex differences in PAH. Here, we identify the gene responsible for Y-chromosome protection, investigate key downstream autosomal genes, and demonstrate a novel preclinical therapy. Methods: To test the effect of Y-chromosome genes on PH development, we knocked down each Y-chromosome gene expressed in the lung by means of intratracheal instillation of siRNA in gonadectomized male mice exposed to hypoxia and monitored changes in right ventricular and pulmonary artery hemodynamics. We compared the lung transcriptome of Uty knockdown mouse lungs to those of male and female PAH patient lungs to identify common downstream pathogenic chemokines and tested the effects of these chemokines on human pulmonary artery endothelial cells. We further inhibited the activity of these chemokines in two preclinical pulmonary hypertension models to test the therapeutic efficacy. Measurements and Main Results: Knockdown of the Y-chromosome gene Uty resulted in more severe PH measured by increased right ventricular pressure and decreased pulmonary artery acceleration time. RNA sequencing revealed an increase in proinflammatory chemokines Cxcl9 and Cxcl10 as a result of Uty knockdown. We found CXCL9 and CXCL10 significantly upregulated in human PAH lungs, with more robust upregulation in females with PAH. Treatment of human pulmonary artery endothelial cells with CXCL9 and CXCL10 triggered apoptosis. Inhibition of Cxcl9 and Cxcl10 expression in male Uty knockout mice and CXCL9 and CXCL10 activity in female rats significantly reduced PH severity. Conclusions:Uty is protective against PH. Reduction of Uty expression results in increased expression of proinflammatory chemokines Cxcl9 and Cxcl10, which trigger endothelial cell death and PH. Inhibition of CLXC9 and CXLC10 rescues PH development in multiple experimental models.

Sex-limited chromosomes and non-reproductive traits

Sex chromosomes are typically viewed as having originated from a pair of autosomes, and differentiated as the sex-limited chromosome (e.g. Y) has degenerated by losing most genes through cessation of recombination. While often thought that degenerated sex-limited chromosomes primarily affect traits involved in sex determination and sex cell production, accumulating evidence suggests they also influence traits not sex-limited or directly involved in reproduction. Here, we provide an overview of the effects of sex-limited chromosomes on non-reproductive traits in XY, ZW or UV sex determination systems, and discuss evolutionary processes maintaining variation at sex-limited chromosomes and molecular mechanisms affecting non-reproductive traits.

Atherosclerosis: Recent developments

Atherosclerosis is an inflammatory disease of the large arteries that is the major cause of cardiovascular disease (CVD) and stroke. Here, we review the current understanding of the molecular, cellular, genetic, and environmental contributions to atherosclerosis, from both individual pathway and systems perspectives. We place an emphasis on recent developments, some of which have yielded unexpected biology, including previously unknown heterogeneity of inflammatory and smooth muscle cells in atherosclerotic lesions, roles for senescence and clonal hematopoiesis, and links to the gut microbiome.

Sex-Associated Differences in Neurovascular Dysfunction During Ischemic Stroke

Neurovascular units (NVUs) are basic functional units in the central nervous system and include neurons, astrocytes and vascular compartments. Ischemic stroke triggers not only neuronal damage, but also dissonance of intercellular crosstalk within the NVU. Stroke is sexually dimorphic, but the sex-associated differences involved in stroke-induced neurovascular dysfunction are studied in a limited extend. Preclinical studies have found that in rodent models of stroke, females have less neuronal loss, stronger repairing potential of astrocytes and more stable vascular conjunction; these properties are highly related to the cerebroprotective effects of female hormones. However, in humans, these research findings may be applicable only to premenopausal stroke patients. Women who have had a stroke usually have poorer outcomes compared to men, and because stoke is age-related, hormone replacement therapy for postmenopausal women may exacerbate stroke symptoms, which contradicts the findings of most preclinical studies. This stark contrast between clinical and laboratory findings suggests that understanding of neurovascular differences between the sexes is limited. Actually, apart from gonadal hormones, differences in neuroinflammation as well as genetics and epigenetics promote the sexual dimorphism of NVU functions. In this review, we summarize the confirmed sex-associated differences in NVUs during ischemic stroke and the possible contributing mechanisms. We also describe the gap between clinical and preclinical studies in terms of sexual dimorphism.

Genetic, Molecular, and Cellular Determinants of Sex-Specific Cardiovascular Traits

Despite the well-known sex dimorphism in cardiovascular disease traits, the exact genetic, molecular, and cellular underpinnings of these differences are not well understood. A growing body of evidence currently points at the links between cardiovascular disease traits and the genome, epigenome, transcriptome, and metabolome. However, the sex-specific differences in these links remain largely unstudied due to challenges in bioinformatic methods, inadequate statistical power, analytic costs, and paucity of valid experimental models. This review article provides an overview of the literature on sex differences in genetic architecture, heritability, epigenetic changes, transcriptomic signatures, and metabolomic profiles in relation to cardiovascular disease traits. We also review the literature on the associations between sex hormones and cardiovascular disease traits and discuss the potential mechanisms underlying these associations, focusing on human studies.

Y chromosome is moving out of sex determination shadow

Although sex hormones play a key role in sex differences in susceptibility, severity, outcomes, and response to therapy of different diseases, sex chromosomes are also increasingly recognized as an important factor. Studies demonstrated that the Y chromosome is not a 'genetic wasteland' and can be a useful genetic marker for interpreting various male-specific physiological and pathophysiological characteristics. Y chromosome harbors male‑specific genes, which either solely or in cooperation with their X-counterpart, and independent or in conjunction with sex hormones have a considerable impact on basic physiology and disease mechanisms in most or all tissues development. Furthermore, loss of Y chromosome and/or aberrant expression of Y chromosome genes cause sex differences in disease mechanisms. With the launch of the human proteome project (HPP), the association of Y chromosome proteins with pathological conditions has been increasingly explored. In this review, the involvement of Y chromosome genes in male-specific diseases such as prostate cancer and the cases that are more prevalent in men, such as cardiovascular disease, neurological disease, and cancers, has been highlighted. Understanding the molecular mechanisms underlying Y chromosome-related diseases can have a significant impact on the prevention, diagnosis, and treatment of diseases.

Genome sequencing reveals the role of rare genomic variants in Chinese patients with symptomatic intracranial atherosclerotic disease

Objectives

The predisposition of intracranial atherosclerotic disease (ICAD) to East Asians over Caucasians infers a genetic basis which, however, remains largely unknown. Higher prevalence of vascular risk factors (VRFs) in Chinese over Caucasian patients who had a stroke, and shared risk factors of ICAD with other stroke subtypes indicate genes related to VRFs and/or other stroke subtypes may also contribute to ICAD.

Methods

Unrelated symptomatic patients with ICAD were recruited for genome sequencing (GS, 60-fold). Rare and potentially deleterious single-nucleotide variants (SNVs) and small insertions/deletions (InDels) were detected in genome-wide and correlated to genes related to VRFs and/or other stroke subtypes. Rare aneuploidies, copy number variants (CNVs) and chromosomal structural rearrangements were also investigated. Lastly, candidate genes were used for pathway and gene ontology enrichment analysis.

Results

Among 92 patients (mean age at stroke onset 61.0±9.3 years), GS identified likely ICAD-associated rare genomic variants in 54.3% (50/92) of patients. Forty-eight patients (52.2%, 48/92) had 59 rare SNVs/InDels reported or predicted to be deleterious in genes related to VRFs and/or other stroke subtypes. None of the 59 rare variants were identified in local subjects without ICAD (n=126). 31 SNVs/InDels were related to conventional VRFs, and 28 were discovered in genes related to other stroke subtypes. Our study also showed that rare CNVs (n=7) and structural rearrangement (a balanced translocation) were potentially related to ICAD in 8.7% (8/92) of patients. Lastly, candidate genes were significantly enriched in pathways related to lipoprotein metabolism and cellular lipid catabolic process.

Conclusions

Our GS study suggests a role of rare genomic variants with various variant types contributing to the development of ICAD in Chinese patients.

Importance of sex and gender in ischaemic stroke and carotid atherosclerotic disease

Stroke is a leading cause of death and disability worldwide. Women are disproportionately affected by stroke, exhibiting higher mortality and disability rates post-stroke than men. Clinical stroke research has historically included mostly men and studies were not properly designed to perform sex- and gender-based analyses, leading to under-appreciation of differences between men and women in stroke presentation, outcomes, and response to treatment. Reasons for these differences are likely multifactorial; some are due to gender-related factors (i.e. decreased social support, lack of stroke awareness), yet others result from biological differences between sexes. Unlike men, women often present with 'atypical' stroke symptoms. Lack of awareness of 'atypical' presentation has led to delays in hospital arrival, diagnosis, and treatment of women. Differences also extend to carotid atherosclerotic disease, a cause of stroke, where plaques isolated from women are undeniably different in morphology/composition compared to men. As a result, women may require different treatment than men, as evidenced by the fact that they derive less benefit from carotid revascularization than men but more benefit from medical management. Despite this, women are less likely than men to receive medical therapy for cardiovascular risk factor management. This review focuses on the importance of sex and gender in ischaemic stroke and carotid atherosclerotic disease, summarizing the current evidence with respect to (i) stroke incidence, mortality, awareness, and outcomes, (ii) carotid plaque prevalence, morphology and composition, and gene connectivity, (iii) the role of sex hormones and sex chromosomes in atherosclerosis and ischaemic stroke risk, and (iv) carotid disease management.

Sex-specific gene expression in the blood of four primates

Blood is an important non-reproductive tissue, but little is known about the sex-specific gene expressions in the blood. Therefore, we investigated sex-specific gene expression differences in the blood tissues of four primates, rhesus macaques (Macaca mulatta), Tibetan macaques (M. thibetana), yellow baboons (Papio cynocephalus), and humans. We identified seven sex-specific differentially expressed genes (SDEGs) in each non-human primate and 31 SDEGs in humans. The four primates had only one common SDEG, MAP7D2. In humans, immune-related SDEGs were identified as up-regulated, but also down-regulated in females. We also found that most of the X-Y gene pairs had similar expression levels between species, except pair EIF1AY/EIF1AX. The expression level of X-Y gene pairs of rhesus and Tibetan macaques showed no significant differential expression levels, while humans had six significant XY-biased and three XX-biased X-Y gene pairs. Our observed sex differences in blood should increase understanding of sex differences in primate blood tissue.

Pathophysiology of Atherosclerotic Plaque Development-Contemporary Experience and New Directions in Research

Atherosclerotic plaque is the pathophysiological basis of important and life-threatening diseases such as myocardial infarction. Although key aspects of the process of atherosclerotic plaque development and progression such as local inflammation, LDL oxidation, macrophage activation, and necrotic core formation have already been discovered, many molecular mechanisms affecting this process are still to be revealed. This minireview aims to describe the current directions in research on atherogenesis and to summarize selected studies published in recent years-in particular, studies on novel cellular pathways, epigenetic regulations, the influence of hemodynamic parameters, as well as tissue and microorganism (microbiome) influence on atherosclerotic plaque development. Finally, some new and interesting ideas are proposed (immune cellular heterogeneity, non-coding RNAs, and immunometabolism) which will hopefully bring new discoveries in this area of investigation.

Y chromosome copy number variation and its effects on fertility and other health factors: a review

The Y chromosome is essential for testis development and spermatogenesis. It is a chromosome with the lowest gene density owing to its medium size but paucity of coding genes. The Y chromosome is unique in that the majority of its structure is highly repetitive sequences, with the majority of these limited genes occurring in 9 amplionic sequences throughout the chromosome. The repetitive nature has its benefits as it can be protective against gene loss over many generations, but it can also predispose the Y chromosome to having wide variations of the number of gene copies present in these repeated sequences. This is known as copy number variation. Copy number variation is not unique to the Y chromosome but copy number variation is a well-known cause of male infertility and having effects on spermatogenesis. This is most commonly seen as deletions of the AZF sequences on the Y chromosome. However, there are other implications for copy number variation beyond just the AZF deletions that can affect spermatogenesis and potentially have other health implications. Copy number variations of TSPY1, DAZ, CDY1, RBMY1, the DYZ1 array, along with minor deletions of gr/gr, b1/b3, and b2/b3 have all be implicated in affecting spermatogenesis. UTY copy number variations have been implicated in risk for cardiovascular disease, and other deletions within gr/gr and the AZF sequences have been implicated in cancer and neuropsychiatric diseases. This review sets out to describe the Y chromosome and unique susceptibility to copy number variation and then to examine how this growing body of research impacts spermatogenesis and other health factors.

Preliminary study between Y chromosome haplogroups and chagasic cardiomyopathy manifestations in patients with Chagas disease

INTRODUCTION

Among patients with Chagas disease, men have a higher risk of worse pathological symptoms than women. We aimed to explore the role of the Y chromosome in men diagnosed with Chagas disease and assess the relationship between their ancestry and disease status.

METHODS

In this comparative study, we analyzed 150 men with unrelated non-chagasic disease (nCD) and 150 men with unrelated chagasic disease (CD). We assessed the serological diagnosis of Chagas disease, biochemical parameters, thoracic X-rays, electrocardiogram, and transthoracic echocardiography and determined the haplogroup by analyzing a set of 17 microsatellites from the Y chromosome. We examined the associations between common Y chromosome haplogroups and the clinical parameters of risk by logistic regression.

RESULTS

For all patients, the most common haplogroups were R1b (43%), G2a (9%), and E1b1b (9%). The R1b and G2a haplogroup was more frequent in men with nCD and CD, respectively. As expected, we observed a high proportion of symptomatic patients in the CD group independent of the haplogroups. Men from both groups classified as having the R1b haplogroup showed less clinical evidence of disease. Multivariate analysis showed that CD patients without R1b were about five times more likely to have a cardio-thorax index >0.5% (OR [odds ratio] = 5.1, 95% CI [confidence interval] = 3.31-8.17). Men without the R1b haplogroup were 2.5 times more likely to show EcoCG alterations (OR = 2.50, 95% CI = 0.16-3.94).

CONCLUSIONS

Our results provided evidence that the R1b haplogroup may have a potential protective cardiovascular effect for its carriers.

Regulatory effects of the Uty/Ddx3y locus on neighboring chromosome Y genes and autosomal mRNA transcripts in adult mouse non-reproductive cells

In addition to sperm-related genes, the male-specific chromosome Y (chrY) contains a class of ubiquitously expressed and evolutionary conserved dosage-sensitive regulator genes that include the neighboring Uty, Ddx3y and (in mice) Eif2s3y genes. However, no study to date has investigated the functional impact of targeted mutations of any of these genes within adult non-reproductive somatic cells. We thus compared adult male mice carrying a gene trap within their Uty gene (Uty^GT) to their wild-type (WT) isogenic controls, and performed deep sequencing of RNA and genome-wide profiling of chromatin features in extracts from either cardiac tissue, cardiomyocyte-specific nuclei or purified cardiomyocytes. The apparent impact of Uty^GT on gene transcription concentrated mostly on chrY genes surrounding the locus of insertion, i.e. Uty, Ddx3y, long non-coding RNAs (lncRNAs) contained within their introns and Eif2s3y, in addition to possible effects on the autosomal Malat1 lncRNA. Notwithstanding, Uty^GT also caused coordinate changes in the abundance of hundreds of mRNA transcripts related to coherent cell functions, including RNA processing and translation. The results altogether indicated that tightly co-regulated chrY genes had nonetheless more widespread effects on the autosomal transcriptome in adult somatic cells, most likely due to mechanisms other than just transcriptional regulation of corresponding protein-coding genes.

Immunogenetics of Atherosclerosis-Link between Lipids, Immunity, and Genes

PURPOSE OF REVIEW

Atherosclerosis is a complex disease process with lipid as a traditional modifiable risk factor and therapeutic target in treating atherosclerotic cardiovascular disease (ACVD). Recent evidence indicates that genetic influence and host immune response also are vital in this process. How these elements interact and modify each other and if immune response may emerge as a novel modifiable target remain poorly understood.

RECENT FINDINGS

Numerous preclinical studies have clearly demonstrated that hypercholesterolemia is essential for atherogenesis, but genetic variations and host immune-inflammatory responses can modulate the pro-atherogenic effect of elevated LDL-C. Clinical studies also suggest that a similar paradigm may also be operational in atherogenesis in humans. More importantly each element modifies the biological behavior of the other two elements, forming a triangular relationship among the three. Modulating any one of them will have downstream impact on atherosclerosis. This brief review summarizes the relationship among lipids, genes, and immunity in atherogenesis and presents evidence to show how these elements affect each other. Modulation of immune response, though in its infancy, has a potential to emerge as a novel clinical strategy in treating ACVD.

Intrinsic transcriptomic sex differences in human endothelial cells at birth and in adults are associated with coronary artery disease targets

Sex differences in endothelial cell (EC) biology may reflect intrinsic differences driven by chromosomes or sex steroid exposure and gender differences accumulated over life. We analysed EC gene expression data from boy-girl twins at birth and in non-twin adults to detect sex differences at different stages of life, and show that 14-25% of the EC transcriptome is sex-biased. By combining data from both stages of life, we identified sex differences that are present at birth and maintained throughout life, and those that are acquired over life. Promisingly, we found that genes that present with an acquired sex difference in ECs are more likely to be targets of sex steroids. Annotating both gene sets with data from multiple genome-wide association studies (GWAS) revealed that genes with an intrinsic sex difference in ECs are enriched for coronary artery disease GWAS hits. This study underscores the need for treating sex as a biological variable.

Quantitative analysis of Y-Chromosome gene expression across 36 human tissues

Little is known about how human Y-Chromosome gene expression directly contributes to differences between XX (female) and XY (male) individuals in nonreproductive tissues. Here, we analyzed quantitative profiles of Y-Chromosome gene expression across 36 human tissues from hundreds of individuals. Although it is often said that Y-Chromosome genes are lowly expressed outside the testis, we report many instances of elevated Y-Chromosome gene expression in a nonreproductive tissue. A notable example is EIF1AY, which encodes eukaryotic translation initiation factor 1A Y-linked, together with its X-linked homolog EIF1AX. Evolutionary loss of a Y-linked microRNA target site enabled up-regulation of EIF1AY, but not of EIF1AX, in the heart. Consequently, this essential translation initiation factor is nearly twice as abundant in male as in female heart tissue at the protein level. Divergence between the X and Y Chromosomes in regulatory sequence can therefore lead to tissue-specific Y-Chromosome-driven sex biases in expression of critical, dosage-sensitive regulatory genes.

Cellular Mechanisms of Human Atherogenesis: Focus on Chronification of Inflammation and Mitochondrial Mutations

Atherosclerosis is one of the most common diseases of the cardiovascular system that leads to the development of life-threatening conditions, such as heart attack and stroke. Arthrosclerosis affects various arteries in the human body, but is especially dangerous in the arteries alimenting heart and brain, aorta, and arteries of the lower limbs. By its pathophysiology, atherosclerosis is an inflammatory disease. During the pathological process, lesions of arterial intima in the form of focal thickening are observed, which form atherosclerotic plaques as the disease progresses further. Given the significance of atherosclerosis for the global health, the search for novel effective therapies is highly prioritized. However, despite the constant progress, our understanding of the mechanisms of atherogenesis is still incomplete. One of the remaining puzzles in atherosclerosis development is the focal distribution of atherosclerotic lesions in the arterial wall. It implies the existence of certain mosaicism within the tissue, with some areas more susceptible to disease development than others, which may prove to be important for novel therapy development. There are many hypotheses explaining this phenomenon, for example, the influence of viruses, and the spread in the endothelium of the vessel multinucleated giant endothelial cells. We suggest the local variations of the mitochondrial genome as a possible explanation of this mosaicism. In this review, we discuss the role of genetic variations in the nuclear and mitochondrial genomes that influence the development of atherosclerosis. Changes in the mitochondrial and nuclear genome have been identified as independent factors for the development of the disease, as well as potential diagnostic markers.