Melanoma antigens in pediatric medulloblastoma contribute to tumor heterogeneity and species-specificity of group 3 tumors.

Background: Medulloblastoma (MB) is the most malignant childhood brain cancer. Group 3 MB subtype accounts for about 25% of MB diagnoses and is associated with the most unfavorable outcomes. Herein, we report that more than half of group 3 MB tumors express melanoma antigens (MAGEs), which are potential prognostic and therapeutic markers. MAGEs are tumor antigens, expressed in several types of adult cancers and associated with poorer prognosis and therapy resistance; however, their expression in pediatric cancers is mostly unknown. The aim of this study was to determine whether MAGEs are activated in pediatric MB. Methods: To determine MAGE frequency in pediatric MB, we obtained formalin-fixed paraffin-embedded tissue (FFPE) samples of 34 patients, collected between 2008 - 2015, from the Children's Medical Center Dallas pathology archives and applied our validated reverse transcription quantitative PCR (RT-qPCR) assay to measure the relative expression of 23 MAGE cancer-testis antigen genes. To validate our data, we analyzed several published datasets from pediatric MB patients and patient-derived orthotopic xenografts, totaling 860 patients. We then examined how MAGE expression affects the growth and oncogenic potential of medulloblastoma cells by CRISPR-Cas9- and siRNA-mediated gene depletion. Results: Our RT-qPCR analysis suggested that MAGEs were expressed in group 3/4 medulloblastoma. Further mining of bulk and single-cell RNA-sequencing datasets confirmed that 50-75% of group 3 tumors activate a subset of MAGE genes. Depletion of MAGEAs, B2, and Cs alter MB cell survival, viability, and clonogenic growth due to decreased proliferation and increased apoptosis. Conclusions: These results indicate that targeting MAGEs in medulloblastoma may be a potential therapeutic option for group 3 medulloblastomas. Key Points: Several Type I MAGE CTAs are expressed in >60% of group 3 MBs. Type I MAGEs affect MB cell proliferation and apoptosis. MAGEs are potential biomarkers and therapeutic targets for group 3 MBs. Importance of the Study: This study is the first comprehensive analysis of all Type I MAGE CTAs ( MAGEA , -B , and -C subfamily members) in pediatric MBs. Our results show that more than 60% of group 3 MBs express MAGE genes, which are required for the viability and growth of cells in which they are expressed. Collectively, these data provide novel insights into the antigen landscape of pediatric MBs. The activation of MAGE genes in group 3 MBs presents potential stratifying and therapeutic options.

Neighborhood disadvantage is associated with working memory and hippocampal volumes among older adults.

It is not well understood how neighborhood disadvantage is associated with specific domains of cognitive function and underlying brain health within older adults. Thus, the objective was to examine associations between neighborhood disadvantage, brain health, and cognitive performance, and examine whether associations were more pronounced among women. The study included 136 older adults who underwent cognitive testing and MRI. Neighborhood disadvantage was characterized using the Area Deprivation Index (ADI). Descriptive statistics, bivariate correlations, and multiple regressions were run. Multiple regressions, adjusted for age, sex, education, and depression, showed that higher ADI state rankings (greater disadvantage) were associated with poorer working memory performance (p < .01) and lower hippocampal volumes (p < .01), but not total, frontal, and white matter lesion volumes, nor visual and verbal memory performance. There were no significant sex interactions. Findings suggest that greater neighborhood disadvantage may play a role in working memory and underlying brain structure.

Differential Associations Between the Area Deprivation Index and Measures of Physical Health for Older Black Adults.

OBJECTIVES: This study explored the association between place-based characteristics (e.g., neighborhood socioeconomic deprivation) and physical health within older Black adults, a critical gap in the literature as identified by the National Institute on Minority Health and Health Disparities. METHODS: The sample was from Wave 1 data of Baltimore Study of Black Aging: Patterns of Cognitive Aging (N = 450; Mage = 68.34). Variables included the area deprivation index (ADI), objective (e.g., average blood pressure) and subjective (e.g., self-rated health) measures of physical health. Multiple linear regression models were conducted controlling for key sociodemographic characteristics. RESULTS: Participants reporting better self-rated health and less likely to need help with activities of daily living were significantly more likely to be living in more disadvantaged neighborhoods based on national and state ADI, respectively, even after adjusting for covariates. A significant age and ADI interaction revealed better self-rated health was associated with a more disadvantaged neighborhood particularly for individuals ≤66 years. There was no significant association between ADI and objective physical health measures. DISCUSSION: The findings suggest that national- and state-level place-based characteristics should be considered along with individual-level factors, which can enrich the scientific understanding of how neighborhood characteristics relate to varying health indicators among older Black adults.

NUDT21 limits CD19 levels through alternative mRNA polyadenylation in B cell acute lymphoblastic leukemia.

B cell progenitor acute lymphoblastic leukemia (B-ALL) treatment has been revolutionized by T cell-based immunotherapies-including chimeric antigen receptor T cell therapy (CAR-T) and the bispecific T cell engager therapeutic, blinatumomab-targeting surface glycoprotein CD19. Unfortunately, many patients with B-ALL will fail immunotherapy due to 'antigen escape'-the loss or absence of leukemic CD19 targeted by anti-leukemic T cells. In the present study, we utilized a genome-wide CRISPR-Cas9 screening approach to identify modulators of CD19 abundance on human B-ALL blasts. These studies identified a critical role for the transcriptional activator ZNF143 in CD19 promoter activation. Conversely, the RNA-binding protein, NUDT21, limited expression of CD19 by regulating CD19 messenger RNA polyadenylation and stability. NUDT21 deletion in B-ALL cells increased the expression of CD19 and the sensitivity to CD19-specific CAR-T and blinatumomab. In human B-ALL patients treated with CAR-T and blinatumomab, upregulation of NUDT21 mRNA coincided with CD19 loss at disease relapse. Together, these studies identify new CD19 modulators in human B-ALL.

Contextualizing the racial gradient in covid-19 outcomes: Narratives from HBCU students.

COVID-19 spread across the nation with Black Americans experiencing twice of the prevalence of deaths than White Americans. Black American college students are facing a unique set of biopsychosocial costs including less retention and poorer mental health. Therefore, the purpose of this study was to examine how Historically Black College or University (HBCU) students contextualize COVID-19. Interviews were conducted with 19 participants and lasted 40-60 minutes. They discussed topics including: their COVID-19 knowledge, precautionary measures, and barriers and promoters of school success were covered. Data were coded through semi-open coding and discussed among the research team. Responses were summarized by eight themes: emotional responses, colorblind rhetoric, lack of healthcare, essential work, distrust for the medical field, barriers to precautions like supply shortages and environmental factors, and poor baseline health. These findings may be used to develop interventions that moderate the impact of COVID-19 and future pandemics on mental health.

Emerging roles for tRNAs in hematopoiesis and hematological malignancies.

tRNAs are central players in decoding the genetic code linking codons in mRNAs with cognate amino acids during protein synthesis. Recent discoveries have placed tRNAs as key regulators of gene expression during hematopoiesis, especially in hematopoietic stem cell (HSC) maintenance and immune development. These functions have been shown to be influenced by dynamic changes in tRNA expression, post-transcriptional base modifications, tRNA-interacting proteins, and tRNA fragmentation; these events underlie the complexity of tRNA-mediated regulatory events in hematopoiesis. In this review, we discuss these recent findings and highlight how deregulation of tRNA biogenesis can contribute to hematological malignancies.

Valine tRNA levels and availability regulate complex I assembly in leukaemia.

Although deregulation of transfer RNA (tRNA) biogenesis promotes the translation of pro-tumorigenic mRNAs in cancers1,2, the mechanisms and consequences of tRNA deregulation in tumorigenesis are poorly understood. Here we use a CRISPR-Cas9 screen to focus on genes that have been implicated in tRNA biogenesis, and identify a mechanism by which altered valine tRNA biogenesis enhances mitochondrial bioenergetics in T cell acute lymphoblastic leukaemia (T-ALL). Expression of valine aminoacyl tRNA synthetase is transcriptionally upregulated by NOTCH1, a key oncogene in T-ALL, underlining a role for oncogenic transcriptional programs in coordinating tRNA supply and demand. Limiting valine bioavailability through restriction of dietary valine intake disrupted this balance in mice, resulting in decreased leukaemic burden and increased survival in vivo. Mechanistically, valine restriction reduced translation rates of mRNAs that encode subunits of mitochondrial complex I, leading to defective assembly of complex I and impaired oxidative phosphorylation. Finally, a genome-wide CRISPR-Cas9 loss-of-function screen in differential valine conditions identified several genes, including SLC7A5 and BCL2, whose genetic ablation or pharmacological inhibition synergized with valine restriction to reduce T-ALL growth. Our findings identify tRNA deregulation as a critical adaptation in the pathogenesis of T-ALL and provide a molecular basis for the use of dietary approaches to target tRNA biogenesis in blood malignancies.

Protocol for the determination of intracellular phase separation thresholds.

To date, phase separation studies have largely been limited to in vitro assays using non-native conditions and aggregation-prone recombinant proteins that are often difficult to purify. This protocol describes the determination of relative protein concentration thresholds for phase separation through fluorescent imaging of GFP-tagged proteins in cells. The commercial availability of various plasmids and antibodies, as well as advances in gene editing, allow this procedure to be modified for the study of various phase-separating proteins in their relevant contexts. For complete details on the use and execution of this protocol, please refer to Lee et al. (2020).

Emerging roles of the MAGE protein family in stress response pathways.

The melanoma antigen (MAGE) proteins all contain a MAGE homology domain. MAGE genes are conserved in all eukaryotes and have expanded from a single gene in lower eukaryotes to ∼40 genes in humans and mice. Whereas some MAGEs are ubiquitously expressed in tissues, others are expressed in only germ cells with aberrant reactivation in multiple cancers. Much of the initial research on MAGEs focused on exploiting their antigenicity and restricted expression pattern to target them with cancer immunotherapy. Beyond their potential clinical application and role in tumorigenesis, recent studies have shown that MAGE proteins regulate diverse cellular and developmental pathways, implicating them in many diseases besides cancer, including lung, renal, and neurodevelopmental disorders. At the molecular level, many MAGEs bind to E3 RING ubiquitin ligases and, thus, regulate their substrate specificity, ligase activity, and subcellular localization. On a broader scale, the MAGE genes likely expanded in eutherian mammals to protect the germline from environmental stress and aid in stress adaptation, and this stress tolerance may explain why many cancers aberrantly express MAGEs Here, we present an updated, comprehensive review on the MAGE family that highlights general characteristics, emphasizes recent comparative studies in mice, and describes the diverse functions exerted by individual MAGEs.

Translational Repression of G3BP in Cancer and Germ Cells Suppresses Stress Granules and Enhances Stress Tolerance.

Stress granules (SGs) are membrane-less ribonucleoprotein condensates that form in response to various stress stimuli via phase separation. SGs act as a protective mechanism to cope with acute stress, but persistent SGs have cytotoxic effects that are associated with several age-related diseases. Here, we demonstrate that the testis-specific protein, MAGE-B2, increases cellular stress tolerance by suppressing SG formation through translational inhibition of the key SG nucleator G3BP. MAGE-B2 reduces G3BP protein levels below the critical concentration for phase separation and suppresses SG initiation. Knockout of the MAGE-B2 mouse ortholog or overexpression of G3BP1 confers hypersensitivity of the male germline to heat stress in vivo. Thus, MAGE-B2 provides cytoprotection to maintain mammalian spermatogenesis, a highly thermosensitive process that must be preserved throughout reproductive life. These results demonstrate a mechanism that allows for tissue-specific resistance against stress and could aid in the development of male fertility therapies.

Masculinity ideology and racism as indicators of obesity risk among Black men.

BACKGROUND: Racial inequities in health continue to persist and one major controllable and preventable risk factor is obesity. This study examined whether psychosocial factors such as masculinity ideology and frequency of experiences with racism may be significantly associated with Black men's obesity risk. METHOD: Participants were 125 Black men aged 20-39 years old (M = 23.0, SD = 3.43). They completed surveys to measure masculinity ideology and experiences with racism. In addition, body mass index, waist-to-hip ratio and systolic and diastolic blood pressure readings were collected. Results showed low negative correlations between experiences with racism and masculinity ideology. RESULTS: Results showed significant correlations between experiences with racism and masculinity ideology. There were significant interaction effects between masculinity ideology and experiences with racism for body mass index scores, waist-to-hip ratio and blood pressure. CONCLUSION: Findings indicated that experiences with racism and masculinity ideology interact to impact obesity risk and prevention.

A Comprehensive Guide to the MAGE Family of Ubiquitin Ligases.

Melanoma antigen (MAGE) genes are conserved in all eukaryotes and encode for proteins sharing a common MAGE homology domain. Although only a single MAGE gene exists in lower eukaryotes, the MAGE family rapidly expanded in eutherians and consists of more than 50 highly conserved genes in humans. A subset of MAGEs initially garnered interest as cancer biomarkers and immunotherapeutic targets due to their antigenic properties and unique expression pattern that is primary restricted to germ cells and aberrantly reactivated in various cancers. However, further investigation revealed that MAGEs not only drive tumorigenesis but also regulate pathways essential for diverse cellular and developmental processes. Therefore, MAGEs are implicated in a broad range of diseases including neurodevelopmental, renal, and lung disorders, and cancer. Recent biochemical and biophysical studies indicate that MAGEs assemble with E3 RING ubiquitin ligases to form MAGE-RING ligases (MRLs) and act as regulators of ubiquitination by modulating ligase activity, substrate specification, and subcellular localization. Here, we present a comprehensive guide to MAGEs highlighting the molecular mechanisms of MRLs and their physiological roles in germ cell and neural development, oncogenic functions in cancer, and potential as therapeutic targets in disease.

LIN28 Zinc Knuckle Domain Is Required and Sufficient to Induce let-7 Oligouridylation.

LIN28 is an RNA binding protein that plays crucial roles in pluripotency, glucose metabolism, tissue regeneration, and tumorigenesis. LIN28 binds to the let-7 primary and precursor microRNAs through bipartite recognition and induces degradation of let-7 precursors (pre-let-7) by promoting oligouridylation by terminal uridylyltransferases (TUTases). Here, we report that the zinc knuckle domain (ZKD) of mouse LIN28 recruits TUT4 to initiate the oligouridylation of let-7 precursors. Our crystal structure of human LIN28 in complex with a fragment of pre-let-7f-1 determined to 2.0 Å resolution shows that the interaction between ZKD and RNA is constrained to a small cavity with a high druggability score. We demonstrate that the specific interaction between ZKD and pre-let-7 is necessary and sufficient to induce oligouridylation by recruiting the N-terminal fragment of TUT4 (NTUT4) and the formation of a stable ZKD:NTUT4:pre-let-7 ternary complex is crucial for the acquired processivity of TUT4.

The stressors of being young and Black: Cardiovascular health and Black young adults.

OBJECTIVE: To examine the impact of stressors relevant to the lives of Black young adults including racial, financial, occupational, and general stress and psychological distress on cardiovascular disease (CVD) risk. Specifically, this study examined the relationship between multiple psychosocial stressors and two CVD risk indicators (i.e. obesity and blood pressure). DESIGN: This study used a quantitative design which included surveys, the collection of anthropometric and blood pressure (BP) measures. Participants were 124 Black college students aged 18 to 27 years old. MAIN OUTCOME MEASURES: Participants completed measures to assess psychological distress, general, occupational, financial and racial stress. Measures of body mass index (BMI), waist-to-hip ratio (WHR) and BP were collected to assess CVD risk. RESULTS: Findings indicated a significant effect of internalised racism on BMI and a significant effect of individual racial stress on diastolic BP. Also, depression was significantly associated with systolic BP. There were no significant results for WHR. CONCLUSION: Findings suggested that the relationship among racial stress, psychological distress and CVD be further explored.

Factors Influencing Dating Experiences Among African American Emerging Adults.

This study examined sociocultural factors that impact dating and sexual experiences of heterosexual African American undergraduate college students attending a historically Black institution in the Southeastern United States. Specifically, mate availability and relationship involvement were analyzed to document students' experiences, and how these influences may be associated with sexual decision making and behavior. Data from nine focus groups (N = 57) were aggregated and four subthemes were identified: competition among women, acceptability of mates, high prevalence of casual relationships, and lowered expectations for commitment. Power dynamics emerged as a contributing factor to the types of relationship involvement, sexual decision-making, and behavior among participants. The importance of prevention programs focusing on situational and cultural variables is highlighted. Additionally, implications for professionals working with emerging adults to consider the impact of the gender ratio imbalance, and perceived power distributions on perceptions of dating relationships, and sexual decision making and behavior are addressed.