Dynamic regulation of hypoxia-inducible factor-1α activity is essential for normal B cell development.

B lymphocyte development and selection are central to adaptive immunity and self-tolerance. These processes require B cell receptor (BCR) signaling and occur in bone marrow, an environment with variable hypoxia, but whether hypoxia-inducible factor (HIF) is involved is unknown. We show that HIF activity is high in human and murine bone marrow pro-B and pre-B cells and decreases at the immature B cell stage. This stage-specific HIF suppression is required for normal B cell development because genetic activation of HIF-1α in murine B cells led to reduced repertoire diversity, decreased BCR editing and developmental arrest of immature B cells, resulting in reduced peripheral B cell numbers. HIF-1α activation lowered surface BCR, CD19 and B cell-activating factor receptor and increased expression of proapoptotic BIM. BIM deletion rescued the developmental block. Administration of a HIF activator in clinical use markedly reduced bone marrow and transitional B cells, which has therapeutic implications. Together, our work demonstrates that dynamic regulation of HIF-1α is essential for normal B cell development.

Venous-plexus-associated lymphoid hubs support meningeal humoral immunity.

There is increasing interest in how immune cells in the meninges-the membranes that surround the brain and spinal cord-contribute to homeostasis and disease in the central nervous system1,2. The outer layer of the meninges, the dura mater, has recently been described to contain both innate and adaptive immune cells, and functions as a site for B cell development3-6. Here we identify organized lymphoid structures that protect fenestrated vasculature in the dura mater. The most elaborate of these dural-associated lymphoid tissues (DALT) surrounded the rostral-rhinal confluence of the sinuses and included lymphatic vessels. We termed this structure, which interfaces with the skull bone marrow and a comparable venous plexus at the skull base, the rostral-rhinal venolymphatic hub. Immune aggregates were present in DALT during homeostasis and expanded with age or after challenge with systemic or nasal antigens. DALT contain germinal centre B cells and support the generation of somatically mutated, antibody-producing cells in response to a nasal pathogen challenge. Inhibition of lymphocyte entry into the rostral-rhinal hub at the time of nasal viral challenge abrogated the generation of germinal centre B cells and class-switched plasma cells, as did perturbation of B-T cell interactions. These data demonstrate a lymphoid structure around vasculature in the dura mater that can sample antigens and rapidly support humoral immune responses after local pathogen challenge.

Glutaminase isoforms expression switches microRNA levels and oxidative status in glioblastoma cells.

BACKGROUND: Glutaminase isoenzymes GLS and GLS2 play apparently opposing roles in cancer: GLS acts as an oncoprotein, while GLS2 (GAB isoform) has context specific tumour suppressive activity. Some microRNAs (miRNAs) have been implicated in progression of tumours, including gliomas. The aim was to investigate the effect of GLS and GAB expression on both miRNAs and oxidative status in glioblastoma cells. METHODS: Microarray profiling of miRNA was performed in GLS-silenced LN229 and GAB-transfected T98G human glioblastoma cells and their wild-type counterparts. Results were validated by real-time quantitative RT-PCR. Oxidative status and antioxidant enzymes were determined by spectrophotometric or fluorescence assays in GLS-silenced LN229 and T98G, and GAB-transfected LN229 and T98G. RESULTS: MiRNA-146a-5p, miRNA-140-3p, miRNA-21-5p, miRNA-1260a, and miRNA-92a-3p were downregulated, and miRNA-1246 was upregulated when GLS was knocked down. MiRNA-140-3p, miRNA-1246, miRNA-1260a, miRNA-21-5p, and miRNA-146a-5p were upregulated when GAB was overexpressed. Oxidative status (lipid peroxidation, protein carbonylation, total antioxidant capacity, and glutathione levels), as well as antioxidant enzymes (catalase, superoxide dismutase, and glutathione reductase) of silenced GLS glioblastoma cells and overexpressed GAB glioblastoma cells significantly changed versus their respective control glioblastoma cells. MiRNA-1246, miRNA-1260a, miRNA-146a-5p, and miRNA-21-5p have been characterized as strong biomarkers of glioblastoma proliferation linked to both GLS silencing and GAB overexpression. Total glutathione is a reliable biomarker of glioblastoma oxidative status steadily associated to both GLS silencing and GAB overexpression. CONCLUSIONS: Glutaminase isoenzymes are related to the expression of some miRNAs and may contribute to either tumour progression or suppression through certain miRNA-mediated pathways, proving to be a key tool to switch cancer proliferation and redox status leading to a less malignant phenotype. Accordingly, GLS and GAB expression are especially involved in glutathione-dependent antioxidant defence.

Are there differences in basal thrombophilias and C-reactive protein between women with or without PCOS?

RESEARCH QUESTION: Polycystic ovary syndrome (PCOS) women have increased cardiovascular risks, although it is unclear whether the haemostatic system and coagulation contribute to that increased risk. DESIGN: Women attending the Gynecology Unit of the 'Virgen de la Arrixaca' University Hospital (Murcia, Spain) for routine gynaecological examinations between September 2014 and May 2016 were assessed for PCOS using the Rotterdam criteria (hyperandrogenism [H], oligo/amenorrhoea [O] and polycystic ovarian morphology [POM]) and were classified into four phenotypic. In total, 126 cases were identified and 159 control women were selected. All women underwent physical and gynaecological examinations, and blood tests between the second and fifth day of the menstrual cycle. Differences in hormonal, basal thrombophilia and metabolic parameters, and C-reactive protein (CRP) between PCOS and controls were analysed. RESULTS: After adjusting by BMI and age, PCOS women had higher LH (P < 0.001), testosterone (P < 0.001), free testosterone (P = 0.01) and anti-Müllerian hormone (P < 0.001) and lower FSH (P = 0.03) compared with controls, whereas sex hormone-binding globulin was no different. Cases showed significantly higher protein S, glucose, insulin and insulin resistance (HOMA-IR) compared with controls (P < 0.05). There were no differences in protein C levels, antithrombin III, prothrombin time, homocysteine, D-dimer, factor V Leyden, prothrombin G20210A polymorphism or CRP. The H+O phenotype showed the poorest results for insulin and HOMA-IR (P = 0.04 and 0.05). CONCLUSIONS: The results suggest that there are no differences in the basal thrombophilias between women with and without PCOS. However, PCOS with H+O shows the poorest metabolic profile.

Assessment of anogenital distance as a diagnostic tool in polycystic ovary syndrome.

RESEARCH QUESTION: Is anogenital distance (AGD) a useful clinical tool for predicting polycystic ovarian syndrome (PCOS) and its main National Institutes of Health (NIH) phenotypes? DESIGN: Case-control study conducted between September 2014 and May 2016 at the Department of Obstetrics and Gynecology of the University Clinical Hospital 'Virgen de la Arrixaca' in the Murcia region (south-eastern Spain). One hundred and twenty-six cases of PCOS and 159 controls without PCOS were included. AGD measurements were taken from the anterior clitoral surface to the upper verge of the anus (AGDAC), and from the posterior fourchette to the upper verge of the anus (AGDAF). Parametric and non-parametric tests and receiver operating characteristic (ROC) curves were used to assess associations between AGD and the presence of PCOS and its phenotypes. RESULTS: AGDAC, but not AGDAF, was associated with PCOS and all its phenotypes (P-values < 0.001 to 0.048). The highest area under the curve (0.62; 95% confidence interval 0.55 to 0.71) was obtained for all PCOS with AGDAC with a sensitivity and specificity of 50.0% and 73.0%, and positive and negative predictive value of 59.0% and 64.4%, respectively. CONCLUSIONS: AGDAC could moderately discriminate the presence of PCOS and may be a useful clinical tool.

Presence of polycystic ovary syndrome is associated with longer anogenital distance in adult Mediterranean women.

STUDY QUESTION: Is polycystic ovary syndrome (PCOS) associated with anogenital distance (AGD), a biomarker of fetal androgen exposure, in adult Mediterranean women? SUMMARY ANSWER: Longer AGD is associated with PCOS in adult Mediterranean women. WHAT IS KNOWN ALREADY: AGD is a biomarker of prenatal androgen milieu. Human observational studies have reported that associations between AGD and reproductive parameters in both sexes. Exposure of the female fetus to intrauterine androgens may be a risk factor for PCOS in adulthood. STUDY DESIGN, SIZE, DURATION: This was a case-control study of 126 women with PCOS and 159 controls between September 2014 and May 2016. PARTICIPANTS/MATERIALS, SETTING, METHODS: Cases were attending the gynecology unit of the 'Virgen de la Arrixaca' University Clinical Hospital (Murcia, Spain), and were diagnosed following the Rotterdam criteria. Phenotypic subtypes of PCOS were also assessed. Both prevalent and incident (newly diagnosed) cases were included. Controls were women without PCOS attending the gynecological outpatient clinic for routine gynecological exams. All women completed health questionnaires, and underwent physical and gynecological examinations, including transvaginal ultrasound and blood draw. We obtained measures from the anterior clitoral surface to the upper verge of the anus (AGDAC), and from the posterior fourchette to the upper verge of the anus (AGDAF). Gynecologists performing the AGD measures were blind to the status of the patients. We used unconditional multiple logistic regression to evaluate the association between AGD measurements and PCOS while accounting for relevant covariates and confounders, such as BMI, age and episiotomy. MAIN RESULTS AND THE ROLE OF CHANCE: Cases showed significantly longer AGDAF and AGDAC compared to controls in bivariate analyses (P-values < 0.05). In the final adjusted models, AGDAC, but not AGDAF, was associated with the presence of PCOS (P-values = 0.002-0.008). Women with AGDAC in the upper compared to the lowest tertile were 2.9-times (95% CI 1.4-5.9; P-trend = 0.008) more likely to have PCOS. AGDAC measures were also significantly associated with all of the different phenotypic subtypes of PCOS (ORs = 3.1-5.1; P-values < 0.05). LIMITATIONS REASONS FOR CAUTION: We took into account known and suspected covariates and confounders, but the possibility of chance findings or residual confounding should be noted. As with all observational studies, causal inference is limited, and study selection and information bias should not be ruled out. WIDER IMPLICATIONS OF THE FINDINGS: Our results support the hypothesis that PCOS has an intrauterine origin, and that the hormonal environment in which the fetus develops may be highly relevant. STUDY FUNDING/COMPETING INTEREST: This work was supported by the Ministry of Economy and Competitiveness, Instituto de Salud Carlos III (ISCIII) (AES, Acción Estratégica en Salud), grant No. PI13/01237, and The Seneca Foundation, Murcia Regional Agency of Science and Technology, grant No. 19443/PI/14. There are no competing interests. TRIAL REGISTRATION NUMBER: Not applicable.

Glutamate and Brain Glutaminases in Drug Addiction.

Glutamate is the principal excitatory neurotransmitter in the central nervous system and its actions are related to the behavioral effects of psychostimulant drugs. In the last two decades, basic neuroscience research and preclinical studies with animal models are suggesting a critical role for glutamate transmission in drug reward, reinforcement, and relapse. Although most of the interest has been centered in post-synaptic glutamate receptors, the presynaptic synthesis of glutamate through brain glutaminases may also contribute to imbalances in glutamate homeostasis, a key feature of the glutamatergic hypothesis of addiction. Glutaminases are the main glutamate-producing enzymes in brain and dysregulation of their function have been associated with neurodegenerative diseases and neurological disorders; however, the possible implication of these enzymes in drug addiction remains largely unknown. This mini-review focuses on brain glutaminase isozymes and their alterations by in vivo exposure to drugs of abuse, which are discussed in the context of the glutamate homeostasis theory of addiction. Recent findings from mouse models have shown that drugs induce changes in the expression profiles of key glutamatergic transmission genes, although the molecular mechanisms that regulate drug-induced neuronal sensitization and behavioral plasticity are not clear.

Investigation of anogenital distance as a diagnostic tool in endometriosis.

An association between anogenital distance (AGD) and endometriosis has been reported, suggesting that AGD may be a useful clinical tool in endometriosis. The predictive ability of AGD of women in discriminating presence and type of endometriosis was examined. A case-control study was conducted at the University Hospital 'Virgen de la Arrixaca', Murcia, Spain, between 2014 and 2015. A total of 114 participants diagnosed with endometriosis using ultrasound findings and 105 controls were recruited. Two AGD measurements were obtained: one from the anterior clitoral surface to the upper verge of the anus (AGDAC), and another one from the posterior fourchette to the upper verge of the anus (AGDAF). Parametric and non-parametric tests andreceiver operator characterstic analyses were used to determine relationships between AGD and presence of endometriosis and subgroups (ovarian endometriomas or deep infiltrating endometriosis [DIE]). The AGDAF, but not AGDAC, was associated with presence of endometriomas, DIE (P-values, <0.001-0.02), or both. The highest area under curve (0.91; 95% CI 0.84 to 0.97) was obtained for the DIE subgroup with the AGDAF measurement, with a sensitivity and specificity of 84.4% and 91.4%, respectively. AGDAF can therefore efficiently discriminate the presence of DIE and may be a useful clinical tool.

Bacterial Production of a Pederin Analogue by a Free-Living Marine Alphaproteobacterium.

The polyketide pederin family are cytotoxic compounds isolated from insects, lichen, and marine sponges. During the past decade, different uncultivable bacteria symbionts have been proposed as the real producers of these compounds, such as those found in insects, lichen, and marine sponges, and their trans-AT polyketide synthase gene clusters have been identified. Herein we report the isolation and biological activities of a new analogue of the pederin family, compound 1, from the culture of a marine heterotrophic alphaproteobacterium, Labrenzia sp. PHM005. This is the first report of the production of a pederin-type compound by a free-living marine bacteria that could be cultured in the laboratory.

Endometriomas and deep infiltrating endometriosis in adulthood are strongly associated with anogenital distance, a biomarker for prenatal hormonal environment.

STUDY QUESTION: Is the length of the anogenital distance (AGD), a biomarker of the in-utero prenatal hormonal environment, associated with the presence of endometriomas and deep infiltrating endometriosis (DIE)? SUMMARY ANSWER: Shorter AGD is associated with presence of endometriomas and DIE. WHAT IS KNOWN ALREADY: It is debated whether hormonal exposure to estrogens in utero may be a risk factor for endometriosis in adulthood. AGD is a biomarker of prenatal hormonal environment and observational studies have shown an association between AGD and reproductive parameters in both sexes. STUDY DESIGN, SIZE, DURATION: This case-control study of 114 women with endometriosis (endometriomas and/or DIE) and 105 controls was conducted between September 2014 and May 2015. PARTICIPANTS/MATERIALS, SETTING, METHODS: Cases were attending the Endometriosis Unit of the Hospital. Prevalent as well as incident cases, diagnosed by transvaginal ultrasound (TVUS), were included. Controls were women without endometriosis attending the gynecological outpatient clinic for routine gynecological exams. Participants completed health questionnaires, followed physical and gynecological examinations, including TVUS. Measurements from the anterior clitoral surface to the upper verge of the anus (AGDAC), and from the posterior fourchette to the upper verge of the anus (AGDAF) were obtained in all subjects. Unconditional multiple logistic regression was used to estimate the association between AGD measurements and presence of endometriomas and/or DIE while accounting for important confounders and covariates, including age, body mass index, vaginal delivery or episiotomy. MAIN RESULTS AND THE ROLE OF CHANCE: AGDAF was related to presence of endometriomas and/or DIE. For all cases of endometriosis (endometriomas and DIE), women in the lowest tertile of the AGDAF distribution, compared with the upper tertile, were 7.6-times (95% CI 2.8-21.0; P-trend < 0.001) more likely to have endometriosis. With regard to DIE, women with AGDAF below the median, compared with those with AGDAF above the median, were 41.6-times (95% CI 3.9-438; P-value = 0.002) more likely to have endometriosis. LIMITATIONS, REASONS FOR CAUTION: In case-control studies, information and selection bias has to be ruled out. Physicians conducting the measurement were blind to the status of the patients. Controls came from the same population as the cases. We adjusted for known and suspected confounders and covariates, but the possibility of residual confounding or chance findings should always be considered. As with all observational studies, causal inference is limited. WIDER IMPLICATIONS OF THE FINDINGS: This study suggests that endometriosis, especially the DIE, might have a prenatal origin that may be traced back to the hormonal milieu in which the fetus develops. STUDY FUNDING/COMPETING INTEREST: This work was supported by the Ministry of Economy and Competitiveness, ISCIII (AES), grant no. PI13/01237 and the Seneca Foundation, Murcia Regional Agency of Science and Technology, grant no. 19443/PI/14. The authors have no competing interests to declare. TRIAL REGISTRATION NUMBER: Not applicable.

The Manchester-Fothergill and the Elevate Posterior technique for the correction of a cervical elongation and large enterocele in a patient with bladder exstrophy and multiple surgeries.

INTRODUCTION AND HYPOTHESIS: A 60-year-old woman presented with congenital bladder exstrophy, urinary incontinence since birth, and pelvic organ prolapse since the menopause at the age of 46 years. METHODS: The patient (gravida 2, para 2 by cesarean sections and tubal ligation) described an extensive past surgical history that included epispadias and neourethral procedures, anti-reflux surgery using the Lich-Grégoir technique, bilateral ureterosigmoidostomy achieving continence, uterine fixation after the Doléris operation, and neovaginal reconstruction. The physical examination revealed a fourth-degree enterocele with cervical elongation (POP-Q: Aa-2, Ba-2, C + 3, D + 4, gh:5, pb:2.5, Tvl:6, Ap + 3, Bp +6). Gynecological ultrasound and uro-CT were performed to ensure that the ureterosigmoidostomy had been successful, and CT-based 3D bone reconstructions were obtained to calculate the distance between the pubic rami and the ischial spines. Based on a literature review of the management options for these patients and the specific characteristics of our patient, a decision was made to perform trachelectomy (the Manchester technique with Fothergill stitches) and a polypropylene mesh placement with sacrospinous ligament anchor (Elevate Posterior® PC, AMS). RESULTS: Six months after the surgery, we observed good anatomical and functional results with significant improvement in the patient's quality-of-life scale score. CONCLUSION: We believed that the vaginal approach was minimally invasive with a low risk of morbidity in our patient, who had a very altered anatomy, but produced a satisfactory functional result.

Mammalian glutaminase isozymes in brain.

Glutamine/glutamate homeostasis must be exquisitely regulated in mammalian brain and glutaminase (GA, E.C. 3.5.1.2) is one of the main enzymes involved. The products of GA reaction, glutamate and ammonia, are essential metabolites for energy and biosynthetic purposes but they are also hazardous compounds at concentrations beyond their normal physiological thresholds. The classical pattern of GA expression in mammals has been recently challenged by the discovery of novel transcript variants and protein isoforms. Furthermore, the interactome of brain GA is also starting to be uncovered adding a new level of regulatory complexity. GA may traffic in brain and unexpected locations, like cytosol and nucleus, have been found for GA isoforms. Finally, the expression of GA in glial cells has been reported and its potential implications in ammonia homeostasis are discussed.

NeuroEPO plus (NeuralCIM®) in mild-to-moderate Alzheimer's clinical syndrome: the ATHENEA randomized clinical trial.

BACKGROUND: NeuroEPO plus is a recombinant human erythropoietin without erythropoietic activity and shorter plasma half-life due to its low sialic acid content. NeuroEPO plus prevents oxidative damage, neuroinflammation, apoptosis and cognitive deficit in an Alzheimer's disease (AD) models. The aim of this study was to assess efficacy and safety of neuroEPO plus. METHODS: This was a double-blind, randomized, placebo-controlled, phase 2-3 trial involving participants ≥ 50 years of age with mild-to-moderate AD clinical syndrome. Participants were randomized in a 1:1:1 ratio to receive 0.5 or 1.0 mg of neuroEPO plus or placebo intranasally 3 times/week for 48 weeks. The primary outcome was change in the 11-item cognitive subscale of the AD Assessment Scale (ADAS-Cog11) score from baseline to 48 weeks (range, 0 to 70; higher scores indicate greater impairment). Secondary outcomes included CIBIC+, GDS, MoCA, NPI, Activities of Daily Living Scales, cerebral perfusion, and hippocampal volume. RESULTS: A total of 174 participants were enrolled and 170 were treated (57 in neuroEPO plus 0.5 mg, 56 in neuroEPO plus 1.0 mg and 57 in placebo group). Mean age, 74.0 years; 121 (71.2%) women and 85% completed the trial. The median change in ADAS-Cog11 score at 48 weeks was -3.0 (95% CI, -4.3 to -1.7) in the 0.5 mg neuroEPO plus group, -4.0 (95% CI, -5.9 to -2.1) in the 1.0 mg neuroEPO plus group and 4.0 (95% CI, 1.9 to 6.1) in the placebo group. The difference of neuroEPO plus 0.5 mg vs. placebo was 7.0 points (95% CI, 4.5-9.5) P = 0.000 and between the neuroEPO plus 1.0 mg vs. placebo was 8.0 points (95% CI, 5.2-10.8) P = 0.000. NeuroEPO plus treatment induced a statistically significant improvement in some of clinical secondary outcomes vs. placebo including CIBIC+, GDS, MoCA, NPI, and the brain perfusion. CONCLUSIONS: Among participants with mild-moderate Alzheimer's disease clinical syndrome, neuroEPO plus improved the cognitive evaluation at 48 weeks, with a very good safety profile. Larger trials are warranted to determine the efficacy and safety of neuroEPO plus in Alzheimer's disease. TRIAL REGISTRATION: https://rpcec.sld.cu Identifier: RPCEC00000232.

Atypical B cells and impaired SARS-CoV-2 neutralization following heterologous vaccination in the elderly.

Suboptimal responses to a primary vaccination course have been reported in the elderly, but there is little information regarding the impact of age on responses to booster third doses. Here, we show that individuals 70 years or older (median age 73, range 70-75) who received a primary two-dose schedule with AZD1222 and booster third dose with mRNA vaccine achieve significantly lower neutralizing antibody responses against SARS-CoV-2 spike pseudotyped virus compared with those younger than 70 (median age 66, range 54-69) at 1 month post booster. Impaired neutralization potency and breadth post third dose in the elderly is associated with circulating "atypical" spike-specific B cells expressing CD11c and FCRL5. However, when considering individuals who received three doses of mRNA vaccine, we did not observe differences in neutralization or enrichment in atypical B cells. This work highlights the finding that AdV and mRNA COVID-19 vaccine formats differentially instruct the memory B cell response.

Anogenital distance and anti-Müllerian hormone combined improves the diagnosis of polycystic ovary syndrome.

The objective of this study was to assess the accuracy of the combination of anogenital distance (AGD) and anti-Müllerian hormone (AMH) in the diagnosis of polycystic ovary syndrome (PCOS). The study included women diagnosed with PCOS and a control group who attended the Clinical University Hospital 'Virgen de la Arrixaca' in Murcia (Spain). Serum concentrations of AMH were measured and two AGD measurements were obtained: (i) from the anterior clitoral surface to the upper verge of the anus (AGDAC); and (ii) from the posterior fourchette to the upper verge of the anus (AGDAF). Data were assessed by receiver operator characteristic (ROC) curves. Women with PCOS (n = 126) had significantly larger AGDAC (80.5 ± 11.3 versus 76.0 ± 10.4 mm; p < 0.001) and higher AMH (7.2 ± 4.7 versus 3.1 ± 2.2; p < 0.001) compared to control women (n = 159). Women with serum AMH above 3.8 ng/mL (clinical cut-off used in PCOS) were 9.1 times more likely to have PCOS (95% CI: 5.1-16.2). The area under the ROC curve of combined model of AMH and AGDAC was 0.87 (95% CI: 0.83-0.91). The combined model for predicting PCOS based on AMH and AGDAC has better diagnostic accuracy than that of AMH or AGDAC alone. This model could be useful for clinicians and improve diagnosis and clinical management of these women.

In vivo labeling reveals continuous trafficking of TCF-1+ T cells between tumor and lymphoid tissue.

Improving the efficacy of immune checkpoint therapies will require a better understanding of how immune cells are recruited and sustained in tumors. Here, we used the photoconversion of the tumor immune cell compartment to identify newly entering lymphocytes, determine how they change over time, and investigate their egress from the tumor. Combining single-cell transcriptomics and flow cytometry, we found that while a diverse mix of CD8 T cell subsets enter the tumor, all CD8 T cells retained within this environment for more than 72 h developed an exhausted phenotype, revealing the rapid establishment of this program. Rather than forming tumor-resident populations, non-effector subsets, which express TCF-1 and include memory and stem-like cells, were continuously recruited into the tumor, but this recruitment was balanced by concurrent egress to the tumor-draining lymph node. Thus, the TCF-1+ CD8 T cell niche in tumors is highly dynamic, with the circulation of cells between the tumor and peripheral lymphoid tissue to bridge systemic and intratumoral responses.

Race, Genetic Admixture, and Cognitive Performance in the Cuban Population.

BACKGROUND: Population aging will lead to a dramatic increase in dementia prevalence, which will disproportionally affect racial minorities. The presence of racial differences in dementia prevalence has been widely reported in United States, but there are no relevant studies on this topic in low- and middle-income countries. METHODS: In a cross-sectional survey, 2944 older Cubans were recruited at a community-based level aimed to identify the effects of self-identified race and genetic admixture on cognitive performance. Dementia diagnosis was established using 10/66 Dementia and DSM-IV criteria. APOE-ε4 genotype was determined in 2511 (85%) and genetic admixture was completed for all dementia cases and in a randomly selected sample of cognitive healthy participants (218 dementia cases and 367 participants without dementia). RESULTS: The overall prevalence of dementia was 8.7%, without large or statistically significant differences on dementia prevalence (p = .12) by self-identified race. Mean cognitive scores were similar across racial groups (p = .46). After controlling for age, sex, and education, greater proportion of African ancestry was not associated with cognitive performance (p = .17). CONCLUSIONS: We found no evidence of an independent effect of self-identified race and/or population ancestry on dementia prevalence or cognitive performance. This suggests that observed differences in dementia prevalence among diverse populations may be driven primarily by social determinants of health.

The impact of hypoxia on B cells in COVID-19.

BACKGROUND: Prominent early features of COVID-19 include severe, often clinically silent, hypoxia and a pronounced reduction in B cells, the latter important in defence against SARS-CoV-2. This presentation resembles the phenotype of mice with VHL-deficient B cells, in which Hypoxia-Inducible Factors are constitutively active, suggesting hypoxia might drive B cell abnormalities in COVID-19. METHODS: Detailed B cell phenotyping was undertaken by flow-cytometry on longitudinal samples from patients with COVID-19 across a range of severities (NIHR Cambridge BioResource). The impact of hypoxia on the transcriptome was assessed by single-cell and whole blood RNA sequencing analysis. The direct effect of hypoxia on B cells was determined through immunisation studies in genetically modified and hypoxia-exposed mice. FINDINGS: We demonstrate the breadth of early and persistent defects in B cell subsets in moderate/severe COVID-19, including reduced marginal zone-like, memory and transitional B cells, changes also observed in B cell VHL-deficient mice. These findings were associated with hypoxia-related transcriptional changes in COVID-19 patient B cells, and similar B cell abnormalities were seen in mice kept in hypoxic conditions. INTERPRETATION: Hypoxia may contribute to the pronounced and persistent B cell pathology observed in acute COVID-19 pneumonia. Assessment of the impact of early oxygen therapy on these immune defects should be considered, as their correction could contribute to improved outcomes. FUNDING: Evelyn Trust, Addenbrooke's Charitable Trust, UKRI/NIHR, Wellcome Trust.

The HIF complex recruits the histone methyltransferase SET1B to activate specific hypoxia-inducible genes.

Hypoxia-inducible transcription factors (HIFs) are fundamental to cellular adaptation to low oxygen levels, but it is unclear how they interact with chromatin and activate their target genes. Here, we use genome-wide mutagenesis to identify genes involved in HIF transcriptional activity, and define a requirement for the histone H3 lysine 4 (H3K4) methyltransferase SET1B. SET1B loss leads to a selective reduction in transcriptional activation of HIF target genes, resulting in impaired cell growth, angiogenesis and tumor establishment in SET1B-deficient xenografts. Mechanistically, we show that SET1B accumulates on chromatin in hypoxia, and is recruited to HIF target genes by the HIF complex. The selective induction of H3K4 trimethylation at HIF target loci is both HIF- and SET1B-dependent and, when impaired, correlates with decreased promoter acetylation and gene expression. Together, these findings show SET1B as a determinant of site-specific histone methylation and provide insight into how HIF target genes are differentially regulated.