The N-terminus and alpha-5, alpha-6 helices of the pro-apoptotic protein Bax, modulate functional interactions with the anti-apoptotic protein Bcl-xL

<p>Abstract</p> <p>Background</p> <p>Bcl-2 family proteins are key regulators of mitochondrial integrity and comprise both pro- and anti-apoptotic proteins. Bax a pro-apoptotic member localizes as monomers in the cytosol of healthy cells and accumulates as oligomers in mitochondria of apoptotic cells. The Bcl-2 homology-3 (BH3) domain regulates interactions within the family, but regions other than BH3 are also critical for Bax function. Thus, the N-terminus has been variously implicated in targeting to mitochondria, interactions with BH3-only proteins as well as conformational changes linked to Bax activation. The transmembrane (TM) domains (α5-α6 helices in the core and α9 helix in the C-terminus) in Bax are implicated in localization to mitochondria and triggering cytotoxicity. Here we have investigated N-terminus modulation of TM function in the context of regulation by the anti-apoptotic protein Bcl-x_L.</p> <p>Results</p> <p>Deletion of 29 amino acids in the Bax N-terminus (Bax 30–192) caused constitutive accumulation at mitochondria and triggered high levels of cytotoxicity, not inhibited by Bcl-x_L. Removal of the TM domains (Bax 30–105) abrogated mitochondrial localization but resulted in Bcl-x_Lregulated activation of endogenous Bax and Bax-Bak dependent apoptosis. Inclusion of the α5-α6 helices/TMI domain (Bax 30–146) phenocopied Bax 30–192 as it restored mitochondrial localization, Bcl-x_Lindependent cytotoxicity and was not dependent on endogenous Bax-Bak. Inhibition of function and localization by Bcl-x_Lwas restored in Bax 1–146, which included the TM1 domain. Regardless of regulation by Bcl-x_L, all N-terminal deleted constructs immunoprecipitated Bcl-x_Land converged on caspase-9 dependent apoptosis consistent with mitochondrial involvement in the apoptotic cascade. Sub-optimal sequence alignments of Bax and Bcl-x_Lindicated a sequence similarity between the α5–α6 helices of Bax and Bcl-x_L. Alanine substitutions of three residues (T14A-S15A-S16A) in the N-terminus (Bax-Ala3) attenuated regulation by the serine-threonine kinase Akt/PKB but not by Bcl-x_Lindicative of distinct regulatory mechanisms.</p> <p>Conclusion</p> <p>Collectively, the analysis of Bax deletion constructs indicates that the N-terminus drives conformational changes facilitating inhibition of cytotoxicity by Bcl-x_L. We speculate that the TM1 helices may serve as 'structural antagonists' for BH3-Bcl-x_Linteractions, with this function being regulated by the N-terminus in the intact protein.</p

A clinical pathway for the postoperative management of hypocalcemia after pediatric thyroidectomy reduces blood draws

Objectives Postoperative calcium management is challenging following pediatric thyroidectomy given potential limitations in self-reporting symptoms and compliance with phlebotomy. A protocol was created at our tertiary children's institution utilizing intraoperative parathyroid hormone (PTH) levels to guide electrolyte management during hospitalization. The objective of this study was to determine the effect of a new thyroidectomy postoperative management protocol on two primary outcomes: (1) the number of postoperative calcium blood draws and (2) the length of hospital stay. Study design Institutional review board approved retrospective study (2010–2016). Methods Consecutive pediatric total thyroidectomy and completion thyroidectomy ± neck dissection cases from 1/1/2010 through 8/5/2016 at a single tertiary children's institution were retrospectively reviewed before and after initiation of a new management protocol. All cases after 2/1/2014 comprised the experimental group (post-protocol implementation). The pre-protocol control group consisted of cases prior to 2/1/2014. Multivariable linear and Poisson regression models were used to compare the control and experimental groups for outcome measure of number of calcium lab draws and hospital length of stay. Results 53 patients were included (n = 23, control group; n = 30 experimental group). The median age was 15 years. 41 patients (77.4%) were female. Postoperative calcium draws decreased from a mean of 5.2 to 3.6 per day post-protocol implementation (Rate Ratio = 0.70, p < .001), adjusting for covariates. The mean number of total inpatient calcium draws before protocol initiation was 13.3 (±13.20) compared to 7.2 (±4.25) in the post-protocol implementation group. Length of stay was 2.1 days in the control group and 1.8 days post-protocol implementation (p = .29). Patients who underwent concurrent neck dissection had a longer mean length of stay of 2.32 days compared to 1.66 days in those patients who did not undergo a neck dissection (p = .02). Hypocalcemia was also associated with a longer mean length of stay of 2.41 days compared to 1.60 days in patients who did not develop hypocalcemia (p < .01). Conclusions The number of calcium blood draws was significantly reduced after introduction of a standardized protocol based on intraoperative PTH levels. The hospital length of stay did not change. Adoption of a standardized postoperative protocol based on intraoperative PTH levels may reduce the number of blood draws in children undergoing thyroidectomy

Influence of gender and parental migration on IYCF practices in 6-23-month-old tribal children in Banswara district, India: findings from the cross-sectional PANChSHEEEL study

BACKGROUND: The interdisciplinary Participatory Approach for Nutrition in Children: Strengthening Health, Education, Engineering and Environment Linkages (PANChSHEEEL) study used a participatory approach to develop locally-feasible and tailored solutions to optimise Infant and Young Child Feeding (IYCF) practices at an individual, household, community, and environmental level. This paper aims to evaluate the influence of gender; migration; and Health, Education, Engineering and Environmental (HEEE) factors on IYCF practices, with the primary outcomes being three key complementary-feeding practices of Minimum Dietary Diversity (MDD), Minimum Meal Frequency (MMF) and Minimum Acceptable Diet (MAD). METHODS: A cross-sectional survey of 325 households with children aged 6-23 months was conducted in nine purposively selected villages in two blocks of Banswara district, Rajasthan, India. A survey tool was developed, translated into the local language, pre-tested, and administered in a gender-sensitive manner. Data-collection processes were standardized to ensure quality measures. Association of the primary outcome with 27 variables was tested using a Chi-square test (Mantel-Haenszel method); backward stepwise regression analysis was conducted to assess the impact of effect modifiers (gender, parental migration). RESULTS: Half of the surveyed children were of each gender, and fathers from half of the households were found to have migrated within the previous year to search for additional income. Parental literacy ranged from 60 to 70%. More than half of the households had access to milk-producing animals. Consumption of each of the seven food groups, eggs (4.7% vs 0.7%; p < 0.02), MDD (10.5% vs 3.2%; p < 0.02) and MAD (9.4% vs 2.6%; p < 0.02) were higher for boys than for girls. After controlling for contextual factors, a male child was 4.1 times more likely to get a diet with MDD and 3.8 times more likely to get a diet with MAD. A child from a non-migrant household was 2.0-2.1 times more likely to get a diet with MDD and MAD as compared to a child from a migrant household. However, this association was not found to be statistically significant after regression. Presence of milk-producing animals in households and consumption of milk/milk products by children in the previous 24 h were the other two strong predictors of MDD and MAD, although access to animal milk in the house did not translate to an increase in consumption of milk/milk products by a child. CONCLUSION: Gender discrimination in diet diversity and complementary-feeding practices starts early in childhood with boys having a distinct advantage over girls. In the case of parental migration, further research is required to establish if it has an adverse impact on feeding practices. Emphasis needs to be given to gender issues and other contextual factors when developing strategies to optimise complementary feeding practices. TRIAL REGISTRATION: With UCL ethics [Ethics ID 4032/002] in United Kingdom and with Sigma IRB [10,025/IRB/D/17-18] in India

Role of schools in community mobilisation to improve IYCF practices in 6-24-month-old tribal children in the Banswara district, India: findings from the qualitative PANChSHEEEL study

OBJECTIVE: India has been struggling with infant malnutrition for decades. There is a need to identify suitable platforms for community engagement to promote locally feasible, resource efficient Infant and Young Child Feeding (IYCF) interventions. This study aims to explore if and how schools could represent a site for community engagement in rural India, acting as innovation hubs to foster positive change in partnership with the Angawadi centres. DESIGN: Five-phase formative study; A parallel mixed methods approach structured by a socioecological framework was used for data collection at individual, household and community levels. This paper focuses on the qualitative findings. SETTING: This study was undertaken in nine villages within two blocks, 'Ghatol' and 'Kushalgarh', in the Banswara district of Rajasthan, India. PARTICIPANTS: 17 schools were identified. Interviews were conducted with local opinion leaders and representatives in the education sector, including principals, schoolteachers, block and district education officers. Across the nine study villages, information was gathered from 67 mothers, 58 paternal grandmothers using Focus Discussion Groups (FDGs) and 49 key respondents in Key Informant Interviews. RESULTS: Schools were considered an important community resource. Challenges included limited parental participation and student absenteeism; however, several drivers and opportunities were identified, which may render schools a suitable intervention delivery site. Enrolment rates were high, with schools and associated staff encouraging parental involvement and student attendance. Existing initiatives, including the mid-day meal, play opportunities and education on health and hygiene, further highlight the potential reliability of schools as a platform for community mobilisation. CONCLUSIONS: Schools have been shown to be functional platforms frequently visited and trusted by community members. With teachers and children as change agents, schools could represent a suitable setting for community mobilisation in future wider scale intervention studies. Expanding the supportive environment around schools will be essential to reinforce healthy IYCF practices in the long term

Ets1 Induces Dysplastic Changes When Expressed in Terminally-Differentiating Squamous Epidermal Cells

BACKGROUND: Ets1 is an oncogene that functions as a transcription factor and regulates the activity of many genes potentially important for tumor initiation and progression. Interestingly, the Ets1 oncogene is over-expressed in many human squamous cell cancers and over-expression is highly correlated with invasion and metastasis. Thus, Ets1 is believed to mainly play a role in later stages of the oncogenic process, but not early events. METHODOLOGY/PRINCIPAL FINDINGS: To better define the role of Ets1 in squamous cell carcinogenesis, we generated a transgenic mouse model in which expression of the Ets1 oncogene could be temporally and spatially regulated. Upon Ets1 induction in differentiating cells of stratified squamous epithelium, these mice exhibited dramatic changes in epithelial organization including increased proliferation and blocked terminal differentiation. The phenotype was completely reversed when Ets1 expression was suppressed. In mice where Ets1 expression was re-induced at a later age, the phenotype was more localized and the lesions that developed were more invasive. Many potential Ets1 targets were upregulated in the skin of these mice with the most dramatic being the metalloprotease MMP13, which we demonstrate to be a direct transcriptional target of Ets1. CONCLUSIONS/SIGNIFICANCE: Collectively, our data reveal that upregulation of Ets1 can be an early event that promotes pre-neoplastic changes in epidermal tissues via its regulation of key genes driving growth and invasion. Thus, the Ets1 oncogene may be important for oncogenic processes in both early and late stages of tumor development

Mortality Among Adults With Cancer Undergoing Chemotherapy or Immunotherapy and Infected With COVID-19

Importance: Large cohorts of patients with active cancers and COVID-19 infection are needed to provide evidence of the association of recent cancer treatment and cancer type with COVID-19 mortality. // Objective: To evaluate whether systemic anticancer treatments (SACTs), tumor subtypes, patient demographic characteristics (age and sex), and comorbidities are associated with COVID-19 mortality. // Design, Setting, and Participants: The UK Coronavirus Cancer Monitoring Project (UKCCMP) is a prospective cohort study conducted at 69 UK cancer hospitals among adult patients (≥18 years) with an active cancer and a clinical diagnosis of COVID-19. Patients registered from March 18 to August 1, 2020, were included in this analysis. // Exposures: SACT, tumor subtype, patient demographic characteristics (eg, age, sex, body mass index, race and ethnicity, smoking history), and comorbidities were investigated. // Main Outcomes and Measures: The primary end point was all-cause mortality within the primary hospitalization. // Results: Overall, 2515 of 2786 patients registered during the study period were included; 1464 (58%) were men; and the median (IQR) age was 72 (62-80) years. The mortality rate was 38% (966 patients). The data suggest an association between higher mortality in patients with hematological malignant neoplasms irrespective of recent SACT, particularly in those with acute leukemias or myelodysplastic syndrome (OR, 2.16; 95% CI, 1.30-3.60) and myeloma or plasmacytoma (OR, 1.53; 95% CI, 1.04-2.26). Lung cancer was also significantly associated with higher COVID-19–related mortality (OR, 1.58; 95% CI, 1.11-2.25). No association between higher mortality and receiving chemotherapy in the 4 weeks before COVID-19 diagnosis was observed after correcting for the crucial confounders of age, sex, and comorbidities. An association between lower mortality and receiving immunotherapy in the 4 weeks before COVID-19 diagnosis was observed (immunotherapy vs no cancer therapy: OR, 0.52; 95% CI, 0.31-0.86). // Conclusions and Relevance: The findings of this study of patients with active cancer suggest that recent SACT is not associated with inferior outcomes from COVID-19 infection. This has relevance for the care of patients with cancer requiring treatment, particularly in countries experiencing an increase in COVID-19 case numbers. Important differences in outcomes among patients with hematological and lung cancers were observed