Female Sex Bias Research Articles

Female sex bias in Iberian megalithic societies through bioarchaeology, aDNA and proteomics

Uncertainties regarding traditional osteological methods in biological sex estimation can often be overcome with genomic and proteomic analyses. The combination of the three methodologies has been used for a better understanding of the gender-related funerary rituals at the Iberian megalithic cemetery of Panoría. As a result, 44 individuals have been sexed including, for the first time, non-adults. Contrary to the male bias found in many Iberian and European megalithic monuments, the Panoría population shows a clear sex ratio imbalance in favour of females, with twice as many females as males. Furthermore, this imbalance is found regardless of the criterion considered: sex ratio by tomb, chronological period, method of sex estimation, or age group. Biological relatedness was considered as possible sociocultural explanations for this female-related bias. However, the current results obtained for Panoría are indicative of a female-centred social structure potentially influencing rites and cultural traditions.

Sex bias in FGFR3 somatic mutations in bladder cancer

Abstract Background Strong sex disparities have been observed among patients with bladder cancer (BCa). FGFR3 is one of the most frequently mutated genes in bladder cancer, and there are inconsistencies in its frequency in male and female patients. Methods Here, we conducted a meta-analysis comparing the FGFR3 somatic mutation frequency in men and women among 7351 patients with BCa from 18 cohorts. Results We showed that female patients had a 1.32 times higher risk of having FGFR3 somatic mutations than males. This difference was attributed to mutations occurring at the 2 most frequently mutated sites, S249 and Y375. Additionally, nonsense mutations were more likely to be found in women, whereas indel/frameshift mutations were almost exclusively found in men; however, no difference was noted for missense mutations. Conclusions A female sex bias in FGFR3 somatic mutations was observed in BCa. Well-powered individual participant data analyses addressing the possible confounding effects of other factors (eg, age, ethnicity, smoking status, muscle invasiveness, and molecular subtype), as well as analyses integrating omics and functional investigations, are warranted to further validate and explain the mechanisms of the current findings.

Persistence of social structuring in an arid zone mammal following reintroduction

Animal social relationships affect animal survival, reproduction, and resource exploitation, and are important to translocation success, but little is known on how they are impacted in reintroduced populations. Here, we investigate the social genetic structure in a reintroduced population of boodies (Bettongia lesueur), one of few social burrowing marsupial species in Australia. Pairwise relatedness of male and female individuals located within seven warrens was determined using 12 microsatellite markers, while mitochondrial DNA was used to identify maternal ancestral lineage. Females were significantly more related within warrens than between warrens, while the difference among males was not significant. We also found evidence of fine-scale genetic structure up to distances of 2 km in females consistent with patterns found in natural populations. Although mean relatedness values were low, our results support the hypothesis that boodies exhibit a female social structure. Multiple maternal lineages were present within all warrens with one exception, suggesting boodies appear to be non-selective when living with individuals from different ancestral backgrounds. We found a significant positive relationship between female sex bias and the number of active entrances in each warren. Together, these results suggest that social structuring should be a key consideration in future reintroductions of boodies.

Sex-specific differences in primary Sjögren's disease

Many autoimmune diseases show a striking female sex predilection, including primary Sjögren's disease (pSD). Patients with pSD display exocrine gland pathology, such as salivary hypofunction and salivary and lacrimal gland inflammation. Moreover, many serious systemic disease manifestations are well-documented, including interstitial nephritis, hypergammaglobulinemia and neuropathies. Of note, women and men with pSD display distinct clinical phenotypes. While the underlying reasons for these clinical observations were poorly understood for many years, recent studies provide mechanistic insights into the specific regulatory landscapes that mediate female susceptibility to autoimmunity. We will review factors that contribute to the female sex bias, with an emphasis on those that are most relevant to pSD pathogenesis. Specifically, we will focus on sex hormones in disease, genetic alterations that likely contribute to the significant disease prevalence in females, and studies that provide evidence for the role of the gut microbiota in disease. Lastly, we will discuss therapeutics that are in clinical trials for pSD that may be particularly efficacious in targeting signaling networks that mediate inflammation in a sex-specific manner.

Sex-biased immunological processes drive hidradenitis suppurativa.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition that can manifest with abscesses, sinus tracts, and scarring in the intertriginous areas of the body. HS is characterized by immune dysregulation, featuring elevated levels of myeloid cells, T helper (Th) cells, and pro-inflammatory cytokines, particularly those involved in Th1- and Th17-mediated immunity. In most epidemiological studies, HS shows a strong female sex bias, with reported female-to-male ratios estimated at roughly 3:1, suggesting that sex-related factors contribute to HS pathophysiology. In this article, we review the role of intrinsic and extrinsic factors that contribute to immunological differences between the sexes and postulate their role in the female sex bias observed in HS. We discuss the effects of hormones, X chromosome dosage, genetics, the microbiome, and smoking on sex-related differences in immunity to postulate potential immunological mechanisms in HS pathophysiology. Future studies are required to better characterize sex-biased factors that contribute to HS disease presentations.

Differential effects of oestrogen on class-switch recombination of B cells dependent on sex chromosome complement: a cross-sectional study

<h2>Abstract</h2><h3>Background</h3> Cisgender women have stronger humoral immune responses than do cisgender men, which partly explains their enhanced responses to infection and vaccination, and the female sex bias in many B-cell driven autoimmune disorders. Oestrogen has been shown to augment class-switch recombination defined as the process whereby B cells switch to IgG, IgA, and IgE isotypes. Murine work suggests that this process occurs via upregulation of the enzyme activation-induced cytidine deaminase, encoded by the <i>AICDA</i> gene, responsible for DNA mutations necessary for class-switch recombination. However, the effect of sex determinants on class-switch recombination remains understudied in humans. We aimed to investigate the effect of sex-chromosomal complement and hormonal milieu on B-cell class-switch recombination. <h3>Methods</h3> This cross-sectional study was done at University College London in the UK. We used an in vivo human model with peripheral blood samples from self-defined healthy cisgender men and women (aged 14–31 years) and healthy transgender men and women (aged 15–19 years) who received treatment with gonadotropin-releasing hormone analogue with or without additional testosterone (for transgender men) or oestradiol (for transgender women). Tanner stage during puberty was determined by a self-reported questionnaire for cisgender participants and by a physician-determined assessment before starting treatment for transgender participants. All participants were defined as Tanner stages 4–5 (after puberty) and had no history of autoimmune disorders, serious infections, or other medical conditions. None received vaccines or immune-modifying treatment 3 weeks before the donation. Peripheral blood mononuclear cell phenotyping was performed using flow cytometry and serum phenotyping was done using a LEGENDplex immunoassay (BioLegend, San Diego, USA). RNA sequencing analysis was done for gene expression. An unpaired t test, Mann-Whitney <i>U</i> tests, or a one-way ANOVA were used for statistical analysis, as appropriate. <h3>Findings</h3> Between July 10, 2015, and July 30, 2021, blood samples were obtained from 153 participants (43 cisgender men, 62 cisgender women, 25 transgender men, and 23 transgender women). RNA sequencing was carried out on samples from 22 additional participants (four cisgender males, six cisgender females, five transgender males, and seven transgender females). None were excluded. The median age of participants was 18·0 years (IQR 17·2–19·3). Cisgender men had significantly lower percentages of class-switched (IgD^– CD27⁺) B cells than did cisgender women (unpaired <i>t</i> test mean 12·00 <i>vs</i> 16·07, 95% CI –6·65 to –1·47; p=0·0024), specifically pertaining to decreased IgG⁺ B cells (mean 10·50 <i>vs</i> 17·16, –10·99 to –2·34; p=0·0094). IgG subclasses 1–3 are implicated in response to infection, whereas IgG4 appears to have immunoregulatory effects. Cisgender men showed a higher IgG4 to IgG1 serum ratio compared with cisgender women (mean 0·15 <i>vs</i> 0·06, 0·03 to 0·15; p=0·0039). Oestrogen blockade on a XX background (gonadotropin-releasing hormone analogue) in transgender men resulted in a reduced proportion of class-switched B cells compared with cisgender women (ANOVA mean 10·13 <i>vs</i> 16·07, 1·45 to 10·42; p=0·0062). The ratio of IgG1 to IgG4 subclasses was unaffected. Oestrogen (oestradiol) treatment on a XY background in transgender women showed no overall effect on class-switching (ANOVA mean 9·55 <i>vs</i> 12·00 in cisgender men, –1·25 to 6·15; p=0·26), but IgG4 to IgG1 ratios decreased significantly (Mann-Whitney <i>U</i> median 0·05 [IQR 0·03 to 0·12] <i>vs</i> 0·15 [0·08 to 0·20]; p=0·015). Preliminary analysis showed that <i>AICDA</i> expression was lower in cisgender men (median 1·66 [1·62 to 1·72] <i>vs</i> 1·85 [1·75 to 1·90] in cisgender women; p=0·038), and oestrogen blockade in transgender men resulted in a non-statistically significant reduction compared with cisgender women (median 1·91 [1·86 to 1·97] <i>vs</i> 2·05 [1·94 to 2·10]; p=0·13). No differences were observed in <i>AICDA</i> expression between transgender women treated with oestrogen and cisgender men (median 1·12 [1·09 to 1·20] <i>vs</i> 1·07 [1·04 to 1·15]; p=0·23). <h3>Interpretation</h3> Oestrogen differentially affects B-cell class-switch recombination depending on the sex chromosome complement. On the XX background, oestrogen was associated with increased class-switch recombination, whereas on the XY background this effect was not seen. Further work is needed to elucidate the molecular mechanisms underlying these observations. <h3>Funding</h3> NIHR UCLH Biomedical Research Centre and Lupus UK.

Immune Cell Contributors to the Female Sex Bias in Multiple Sclerosis and Experimental Autoimmune Encephalomyelitis.

Multiple sclerosis (MS) is a chronic, autoimmune, demyelinating disease of the central nervous system (CNS) that leads to axonal damage and accumulation of disability. Relapsing-remitting MS (RR-MS) is the most frequent presentation of MS and this form of MS is three times more prevalent in females than in males. This female bias in MS is apparent only after puberty, suggesting a role for sex hormones in this regulation; however, very little is known of the biological mechanisms that underpin the sex difference in MS onset. Experimental autoimmune encephalomyelitis (EAE) is an animal model of RR-MS that presents more severely in females in certain mouse strains and thus has been useful to study sex differences in CNS autoimmunity. Here, we overview the immunopathogenesis of MS and EAE and how immune mechanisms in these diseases differ between a male and female. We further describe how females exhibit more robust myelin-specific T helper (Th)1 immunity in MS and EAE and how this sex bias in Th cells is conveyed by sex hormone effects on the T cells, antigen presenting cells, regulatory T cells, and innate lymphoid cell populations.

The hidden interplay between sex and COVID-19 mortality: the role of cardiovascular calcification

Recent clinical and demographical studies on COVID-19 patients have demonstrated that men experience worse outcomes than women. However, in most cases, the data were not stratified according to gender, limiting the understanding of the real impact of gender on outcomes. This study aimed to evaluate the disaggregated in-hospital outcomes and explore the possible interactions between gender and cardiovascular calcifications. Data was derived from the sCORE-COVID-19 registry, an Italian multicentre registry that enrolled COVID-19 patients who had undergone a chest computer tomography scan on admission. A total of 1683 hospitalized patients (mean age 67±14 years) were included. Men had a higher prevalence of cardiovascular comorbidities, a higher pneumonia extension, more coronary calcifications (63% vs.50.9%, p<0.001), and a higher coronary calcium score (391±847 vs. 171±479 mm3, p<0.001). Men experienced a significantly higher mortality rate (24.4% vs. 17%, p=0.001), but the death event tended to occur earlier in women (15±7 vs. 8±7 days, p= 0.07). Non-survivors had a higher coronary, thoracic aorta, and aortic valve calcium score. Female sex, a known independent predictor of a favorable outcome in SARS-CoV2 infection, was not protective in women with a coronary calcification volume greater than 100 mm3. There were significant differences in cardiovascular comorbidities and vascular calcifications between men and women with SARS-CoV2 pneumonia. The differences in outcomes can be at least partially explained by the different cardiovascular profiles. However, women with poor outcomes had the same coronary calcific burden as men. The presumed favorable female sex bias in COVID-19 must therefore be reviewed in the context of comorbidities, especially cardiovascular ones.

Estrogen Receptor Alpha Signaling Is Responsible for the Female Sex Bias in the Loss of Tolerance and Immune Cell Activation Induced by the Lupus Susceptibility Locus Sle1b.

The dramatic female sex bias observed in human lupus is thought to be due, at least in part, to estrogens. Using mouse models, we have shown that estrogens, acting through estrogen receptor alpha (ERα) promote lupus development and contribute significantly to the female sex bias observed in this disease. C57Bl/6 (B6) mice carrying the lupus susceptibility locus Sle1 locus exhibit immune cell hyperactivation and loss of tolerance, and the action of Sle1 displays a strong female sex bias. Previously, we showed that disruption of ERα completely eliminates the female sex bias in the effects of Sle1. Here we report that ERα signaling selectively modulates the action of Sle1b, one of the three subloci that together constitute Sle1. We observed that disruption of ERα signaling attenuated T cell hyperactivation, formation of spontaneous germinal centers, loss of tolerance, and the development of anti-chromatin autoantibodies in B6.Sle1b female mice, but had no impact on these phenotypes in B6.Sle1b male mice. In fact, disruption of ERα completely abolished the female sex bias that is seen in each of these phenotypes in B6.Sle1b mice. Strikingly, Sle1b-induced B cell hyperactivation, a female sex-specific manifestation of Sle1b, was completely abrogated by disruption of ERα in B6.Sle1b females. Altogether, these results demonstrate that ERα signaling is responsible for the female sex bias in the actions of Sle1b, and is absolutely required for the female-specific B cell hyperactivation phenotype associated with this lupus susceptibility locus. By contrast, we found that ERα signaling had no impact on Sle1a, the other Sle1 sublocus that exerts effects that show a female sex bias.

Perinatal androgens organize sex differences in mast cells and attenuate anaphylaxis severity into adulthood

Mast cell (MC)-associated diseases, including allergy/anaphylaxis and neuroinflammatory pain disorders, exhibit a sex bias, with females at increase risk. While much attention has been directed toward adult sex hormones as drivers of sex differences, that female sex bias in MC-associated diseases is evident in prepubertal children, suggesting early-life origins of sex differences which have yet to be explored. Utilizing rodent models of MC-mediated anaphylaxis, our data here reveal that, 1) compared with females, males exhibit significantly reduced severity of MC-mediated anaphylactic responses that emerge prior to puberty and persist into adulthood, 2) reduced severity of MC-mediated anaphylaxis in males is linked with the naturally high level of perinatal androgens and can be recapitulated in females by perinatal exposure to testosterone proprionate, 3) perinatal androgen exposure guides bone marrow MC progenitors toward a masculinized tissue MC phenotype characterized by decreased concentration of prestored MC granule mediators (e.g., histamine, serotonin, and proteases) and reduced mediator release upon degranulation, and 4) engraftment of MC-deficient Kit W-sh/W-sh mice with adult male, female, or perinatally androgenized female MCs results in MC-mediated anaphylaxis response that reflects the MC sex and not host sex. Together, these data present evidence that sex differences in MC phenotype and resulting disease severity are established in early life by perinatal androgens. Thus, factors affecting levels of perinatal androgens could have a significant impact on MC development and MC-associated disease risk across the life span.

Evidence of Renal Iron Accumulation in a Male Mouse Model of Lupus.

Lupus nephritis represents a common and serious complication of the autoimmune disease Systemic Lupus Erythematosus (SLE). Clinical studies suggest that several proteins related to iron metabolism, including transferrin, serve as urinary biomarkers of lupus nephritis. We previously reported that in female NZBWF1 mice, a commonly used mouse model of SLE with a female sex bias, increased urinary transferrin excretion and renal iron accumulation occur around the onset of albuminuria. The current study investigated whether similar findings occur in male mice of a different mouse model of SLE, the MRL/lpr mouse. Two different cohorts were studied: MRL/lpr mice at an early, pre-albuminuric age (8 weeks), and after developing albuminuria (>100 mg/dL, confirmed by ELISA); age-matched MRL/MpJ control strain mice served for comparison. Urinary transferrin excretion was dramatically increased in the older, albuminuric MRL/lpr mice compared to the age-matched MRL/MpJ (P < 0.05), but there was no significant difference between strains at 8 weeks of age. Similarly, there were no significant differences between strains in renal cortical or outer medullary non-heme iron concentrations at 8 weeks. In the older, albuminuric MRL/lpr mice, renal cortical and outer medullary non-heme iron concentrations were significantly increased compared with age-matched MRL/MpJ mice, as was the expression of the iron storage protein ferritin (P < 0.01). Together, these data show that increased urinary transferrin excretion and renal tissue iron accumulation also occurs in albuminuric male MRL/lpr mice, suggesting that renal iron accumulation may be a feature of multiple mouse models of SLE.

Sex Hormones, BDNF, Leptin, and TGF-β1 in Females With IBS: A Pilot Investigation.

Irritable bowel syndrome (IBS) is a chronic gastrointestinal condition predominantly affecting the female sex, and is characterized by brain-gut axis dysregulation. Relevance of hormones along the hypothalamic-pituitary gonadal axis and hypothalamic-pituitary adrenal axis to IBS symptomatology remain unclear, as does the significance of other modulators including brain derived neurotrophic factor (BDNF), leptin, and transforming growth factor βeta 1 (TGF-β1). Females with IBS were compared with female healthy controls (HC) on age, race, hormonal contraceptive use, body mass index, adrenocorticotropic hormone, cortisol, estradiol, follicular stimulating hormone, luteinizing hormone, progesterone, total cholesterol, Center for Epidemiological Studies Depression Scale (CES-D) and Perceived Stress Scale (PSS). BDNF, leptin, and TGF-β1 were quantified using enzyme-linked immunosorbent assay. Descriptive statistics, non-parametric techniques, and regression analyses were performed. Participants with IBS (n = 12) displayed higher estradiol (p = .027) than did HC (n = 21). Direction of associations among study variables often differed between groups: BDNF and progesterone in HC (rs = .623) and in IBS (rs = -.723). The relationship between log (CES-D) and log (estradiol) varied by IBS status (interaction term p = 0.019). Elevated estradiol in participants with IBS, and differential patterns of biological and psychological indices between groups, encourages further inquiry on the relevance of sex hormones, BDNF, leptin, and TGF-β1 to symptoms of IBS. Future research endeavors should conduct longitudinal quantification of sex hormones with subjective symptom assessment to facilitate insight on the pathophysiology and female sex bias in IBS.

The Effects of Androgens on T Cells: Clues to Female Predominance in Autoimmune Liver Diseases?

The immune system responds differently in women and in men. Generally speaking, adult females show stronger innate and adaptive immune responses than males. This results in lower risk of developing most of the infectious diseases and a better ability to clear viral infection in women (1–5). On the other hand, women are at increased risk of developing autoimmune diseases (AID) such as rheumatoid arthritis, multiple sclerosis (MS), systemic lupus erythematosus (SLE), Sjögren's syndrome, and the autoimmune liver diseases autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) (6). Factors contributing to the female sex bias in autoimmune diseases include environmental exposure, e.g., microbiome, behavior, and genetics including X chromosomal inactivation of genes. Several lines of evidence and clinical observations clearly indicate that sex hormones contribute significantly to disease pathogenesis, and the role of estrogen in autoimmune diseases has been extensively studied. In many of these diseases, including the autoimmune liver diseases, T cells are thought to play an important pathogenetic role. We will use this mini-review to focus on the effects of androgens on T cells and how the two major androgens, testosterone and dihydrotestosterone, potentially contribute to the pathogenesis of autoimmune liver diseases (AILD).

The (Orf)ull truth about IRF5 and type I interferons in SLE.

Exactly how nucleic acids trigger type I interferon responses via certain Toll-like receptors has been uncertain. Now, a new pathway involving gene products previously linked to systemic lupus erythematosus but not known to interact has been unravelled, which could be of relevance to the female sex bias in this disease.

Perinatal androgen exposure impacts mast cell development and mediator storage

Abstract Mast cell (MC)-associated diseases often exhibit a female sex bias in both prepubertal children and adults. We have shown that female MCs store and release greater amounts of histamine which correlates with heightened anaphylaxis in both prepubertal and adult mice. Further, perinatal androgen exposure, a major organizing event in sex biology, reduced MC histamine storage and release, and the severity of anaphylaxis in prepubertal and adult female mice, thus demonstrating that perinatal androgens are critical early life drivers of MC sex differences, but the mechanisms remain poorly understood. The objective of this study was to determine how perinatal androgens impact MC development. RNA sequencing analysis of BMMCs derived from adult female and male mice that were previously exposed to perinatal androgens revealed significant down-regulation of a number of genes related to granule biogenesis and mediator storage of which included lactotransferrin (by −2.6 fold), proteoglycan 2 (by −3.9 fold), lipocalin 2 (by −1.4-fold), elastase (by −2.5 fold) and myeloperoxidase (by 1.4 fold). Current studies aim to confirm RNA seq data with qPCR and protein expression analysis and to define the critical period of androgen programming on MC development and function. Understanding the mechanisms by which early life androgens drive sex differences in MCs will be critical in understanding the origins of sex differences in MC and its role in health and disease.

The influence of first author sex on acceptance rates of submissions to Anaesthesia Cases.

More than 50% of medical students and 45% of practising doctors are female in the UK. In the specialty of anaesthesia, 32% of consultants are female. However, compared with males, females are under-represented as authors of articles published in high-impact journals. We investigated the proportion of female first authors by examining the case reports submitted to Anaesthesia Cases since its inception in 2013. We defined authors by their sex (male or female), that is, biological characteristics, rather than their gender. There were a total of 802 submissions to Anaesthesia Cases over 4.5years. Sixteen submissions were excluded and of the remaining 786 submissions, 279 were accepted and 507 rejected, an acceptance rate of 35.5%. Twenty (2.5%) authors' sex could not be identified. The overall proportion of female first authors was 37.1%. The proportion of female first authors of accepted case reports was 42.1% and females were first authors of rejected case reports in 34.4%. We found that, compared with previous studies on female sex and gender bias in publishing, there was a relatively high proportion of female first authors publishing in Anaesthesia Cases and female first authors were more likely to be accepted than male first authors. Authorship is considered to reflect career success and there continues to be sex/gender inequity that must be tackled at all levels, from application to medical school, through research funding, journals and Editorial Boards.

Status, conservation and ecology of Pallavicinia lyellii (Hook.) Carruth. in a key region of England

ABSTRACTIntroduction. Pallavicinia lyellii is recognised as being of principal importance for conservation in England and is threatened with extinction in Europe. The aims of this study were to investigate the current status, conservation and ecology of the species in S Hampshire, a key region for the plant.Methods. All recent and historic locations for Pallavicinia lyellii in S Hampshire were searched and information collected on distribution, abundance and ecology.Results. Pallavicinia lyellii was re-found at three sites. It is almost certainly extinct at two sites and may have been lost from a third. Whilst few colonies were sterile, most comprised a single sex. Colonies with both male and female plants were confined to Cadnam Bog, which supported 49 (91%) of the colonies found. Overall, female shoots occurred at 41 (76%) colonies and males at 26 (48%), producing a female sex bias (1.6:1). All colonies occur in boggy woodland, mostly on the sides of low mounds of damp, acidic, peaty soil developed, due to poaching by ponies and cattle, at the base of trees, usually I. aquifolium. The community mainly comprises a species-poor mix of acidophilous mosses and liverworts, most frequently Mnium hornum, Pseudotaxiphyllum elegans and Leucobryum juniperoideum.Conclusions. Cadnam Bog appears to support the largest sexually reproducing population of Pallavicinia lyellii in England. The site is specially protected, actively managed with consideration to P. lyellii and seemingly in favourable condition for the plant. Research is needed to quantify canopy shade favoured by the plant and assess implications for woodland management. Future monitoring should include re-survey of populations every 3 yr.

Perinatal androgens drive sex differences in mast cell phenotype and severity of mast cell disease

Abstract Highly prevalent and debilitating mast cell (MC)-associated immune disorders, such as allergy and irritable bowel syndrome exhibit a female sex bias in childhood and adulthood. The mechanisms underlying sex differences in MC disorders are unknown. Previously, we found adult female mice exhibited greater serum histamine and more severe MC-associated pathophysiology that coincided with an increased capacity to synthesize and store immune mediators, compared with males. Further, recent data showed sex differences in the MC exist prior to puberty, suggesting a mechanism independent of adult sex hormones. Here, we investigated the role of perinatal androgens, a key early life component of sexual differentiation, in sex differences in MC phenotype and MC disease. Testosterone proprionate (100 μg sc qd) or vehicle was given to pregnant female mice E16-P0 and directly to pups PN1-7. IgE-mediated anaphylaxis was performed in gonadectomized control male (CM), control female (CF) and perinatally androgenized female (AF) offspring at 8 wk of age. Serum histamine levels (CM 768 ± 106, CF 1406 ± 200, AF 676 ± 110 ng/mL) and hypothermia responses (Δ temp: CM −4.87 ± 0.45, CF − 7.28 ± 0.48, AF − 4.8 ± 0.39 °C) were ~2x lower in AF than CF mice, while AF and CM mice had similar responses. Further, bone marrow MC from AF mice had lower histamine content (AF 1305 ± 82: CF 2082 ± 94 ng/106cells) and 47% lower histamine release to IgE-FcɛRI stimulus compared to CF mice. Together, we demonstrate that sex differences in MC phenotype and disease susceptibility are established early in life by perinatal androgens. These findings provide insight into the mechanisms of sex differences in MC-associated immune disorders that could lead to new therapeutic targets for MC diseases.

05 SUSTAINED EXPRESSION OF GLUCOCORTICOID-INDUCED LEUCINE ZIPPER (GILZ) MARKS A POPULATION OF FUNCTIONALLY IMMATURE INTESTINAL REGULATORY T CELLS IN FEMALE CROHN’S DISEASE PATIENTS

In addition to its classic roles in sexual development and function, estrogen (“E2”) is an important immune regulator. The impact of E2 in a given cell is determined by the relative contribution of signaling downstream of two ligand-activated nuclear receptors, estrogen receptors alpha and beta (ERa, ERb), with ERb generally mediating anti-inflammatory effects. Altered ER signaling likely contributes to the female sex bias observed for many autoimmune diseases including Crohn’s disease (CD). We observed reduced ERb expression in inflamed mucosal tissues and peripheral blood T cells from female CD patients, suggesting that reductions in ERb signaling may promote chronic intestinal inflammation in females. To investigate the contribution of ERb signaling in an experimental ileitis model, we backcrossed mice lacking ERb (ERb-KO) onto SAMP/YitFc (SAMP) mice, generating SAMP-ERb-KO mice lacking global ERb expression. CD patient T cells were FACS-sorted from heparinized peripheral blood from adult volunteers naïve to biologic therapies and corticosteroids. SAMP-ERb-KO mice demonstrated a female-specific exacerbation of ileitis, in which ileal inflammation developed at an earlier age and to a more severe extent in SAMP-ERb-KO female mice compared to SAMP-ERb-KO male mice or to native SAMP mice expressing ERb. Flow cytometric analysis of CD4+ T cells isolated from the mesenteric lymph node (MLN) revealed a decrease in regulatory T cell (Treg) frequency and suppressive function in SAMP-ERb-KO female mice, with a significant reduction in peripherally-induced Tregs. Next-generation RNA sequencing of intestinal Tregs from SAMP-ERb-KO male versus female mice revealed sex-based differences in the expression of several target genes. The most significant of these was Tsc22d3 (GILZ), a glucocorticoid-induced leucine zipper gene showing five-fold upregulation in Tregs from SAMP-ERb-KO female mice. We observed similar overexpression of GILZ in Tregs isolated from female CD patients. GILZ is an E2-regulated gene that affects several aspects of T cell function including peripheral Treg differentiation and Th17 responses. GILZ expression has not been previously observed in mature Tregs. Our data reveal that sustained expression of GILZ in SAMP-ERb-KO female Tregs correlates with impaired suppressive function, suggesting that ERb-mediated negative regulation of GILZ in peripheral Tregs represents an important immunoregulatory circuit contributing to peripheral Treg homeostasis. We show that female SAMP-ERb-KO mice and female CD patients exhibit reductions in anti-inflammatory ERb expression, leading to sustained expression of GILZ among peripheral Tregs. Sustained GILZ expression marks a population of immature, functionally insufficient Tregs that may contribute to the enhanced inflammation frequently observed in female CD patients.

Sexing Viking Age horses from burial and non-burial sites in Iceland using ancient DNA

Horses are the most common grave goods found in Icelandic Viking Age graves. Horse skeletons have previously been sexed based on pelvis shape and the presence of canine teeth in male horses over 4–5 years of age. Morphological data has shown that all horses from Icelandic burials that were amenable to sexing were male. Yet the use of morphological methods to determine sex is problematic since they rely on finding a well-preserved pelvis and/or robust canine teeth. Furthermore, quantitative data underlying the features of the horse pelvis used for sexing is lacking and canine teeth have been reported to occur in mares. In this study we build upon and extend recently developed methodologies to make use of shotgun sequencing of ancient DNA (aDNA) for molecular sexing of Viking Age horse remains. With minimal sequencing effort we identified the sex of the largest collection (n = 22) of Viking Age Icelandic horses studied to date, sourced from both burial (n = 19) and non-burial (n = 3) sites. Our results revealed a male to female sex bias ratio of 18:1 in burial sites, versus 0:3 in non-burial sites. These findings support the significant over-representation of male horses in Viking Age graves in Iceland, yet show that –albeit rare– mares could also be selected for ritual burial in Viking Age Iceland. This cost-effective method provides statistical confidence to allow for sexing of highly fragmented archaeological specimens with low endogenous DNA content.