A global update on the status of prevention of folic acid-preventable spina bifida and anencephaly in year 2022.

BACKGROUND: Mandatory fortification of staple foods with folic acid is an effective public health strategy to prevent folic acid-preventable spina bifida and anencephaly (FAP SBA). We estimated the global proportion of FAP SBA prevented through mandatory folic acid fortification of cereal grains (i.e., wheat flour, maize flour, and rice). METHODS: We used year 2022 data from the Food Fortification Initiative to identify countries (n = 69) with mandatory fortification of grains that includes folic acid. Sixty-eight countries were eligible for analysis with complete data. Proportion of FAP SBA prevention was modeled assuming >150 mcg/day of folic acid fortification protects against FAP SBA, reducing post-fortification prevalence to a lowest achievable level of 0.5 cases per 1000 births. RESULTS: Our analysis found that a total of 63,520 cases of FAP SBA were prevented in the year 2022 in 68 countries implementing mandatory folic acid fortification of grains with folic acid. This translated to a 23.7% prevention of all possible FAP SBA prevention globally. An excess of 204,430 cases of FAPSBA still occurred in over 100 countries where mandatory staple food fortification with folic acid is not implemented. CONCLUSION: Our study showed that only a quarter of all FAP SBA cases were averted through mandatory folic acid fortification in the year 2022; many countries are not implementing the policy, resulting in a large proportion of FAP SBA cases that can be prevented. Fortification will help countries with achieving 2030 Sustainable Development Goals on neonatal- and under-five mortality, disability, stillbirths, and elective terminations prevention, from FAP SBA.

Transcription Factor Dynamics: One Molecule at a Time.

Cells must tightly regulate their gene expression programs and yet rapidly respond to acute biochemical and biophysical cues within their environment. This information is transmitted to the nucleus through various signaling cascades, culminating in the activation or repression of target genes. Transcription factors (TFs) are key mediators of these signals, binding to specific regulatory elements within chromatin. While live-cell imaging has conclusively proven that TF-chromatin interactions are highly dynamic, how such transient interactions can have long-term impacts on developmental trajectories and disease progression is still largely unclear. In this review, we summarize our current understanding of the dynamic nature of TF functions, starting with a historical overview of early live-cell experiments. We highlight key factors that govern TF dynamics and how TF dynamics, in turn, affect downstream transcriptional bursting. Finally, we conclude with open challenges and emerging technologies that will further our understanding of transcriptional regulation.

Dynamic switching of transcriptional regulators between two distinct low-mobility chromatin states.

How chromatin dynamics relate to transcriptional activity remains poorly understood. Using single-molecule tracking, coupled with machine learning, we show that histone H2B and multiple chromatin-bound transcriptional regulators display two distinct low-mobility states. Ligand activation results in a marked increase in the propensity of steroid receptors to bind in the lowest-mobility state. Mutational analysis revealed that interactions with chromatin in the lowest-mobility state require an intact DNA binding domain and oligomerization domains. These states are not spatially separated as previously believed, but individual H2B and bound-TF molecules can dynamically switch between them on time scales of seconds. Single bound-TF molecules with different mobilities exhibit different dwell time distributions, suggesting that the mobility of TFs is intimately coupled with their binding dynamics. Together, our results identify two unique and distinct low-mobility states that appear to represent common pathways for transcription activation in mammalian cells.

The Glucocorticoid Receptor is Required for Efficient Aldosterone-Induced Transcription by the Mineralocorticoid Receptor.

The glucocorticoid and mineralocorticoid receptors (GR and MR, respectively) have distinct, yet overlapping physiological and pathophysiological functions. There are indications that both receptors interact functionally and physically, but the precise role of this interdependence is poorly understood. Here, we analyzed the impact of GR co-expression on MR genome-wide chromatin binding and transcriptional responses to aldosterone and glucocorticoids, both physiological ligands of this receptor. Our data show that GR co-expression alters MR genome-wide binding to consensus DNA sequences in a locus- and ligand-specific way. MR binding to consensus DNA sequences is affected by GR. Transcriptional responses of MR in the absence of GR are weak and show poor correlation with chromatin binding. In contrast, co-expression of GR potentiates MR-mediated transcription, particularly in response to aldosterone. Finally, single-molecule tracking of MR suggests that the presence of GR contributes to productive binding of MR/aldosterone complexes to chromatin. Together, our data indicate that co-expression of GR potentiates aldosterone-mediated MR transcriptional activity, even in the absence of glucocorticoids.

A global update on the status of prevention of folic acid-preventable spina bifida and anencephaly in year 2020: 30-Year anniversary of gaining knowledge about folic acid's prevention potential for neural tube defects.

BACKGROUND: Spina bifida and anencephaly are major neural tube defects largely preventable through maternal periconceptional intake of folic acid. We estimated the global proportion of folic acid-preventable spina bifida and anencephaly (FAP SBA) prevented through mandatory folic acid fortification of cereal grains, including wheat flour, maize flour, and rice, at the end of year 2020, a time point marking the 30th anniversary of the publication of landmark British Medical Research Council (MRC) study providing unequivocal knowledge on folic acid's FAP SBA prevention potential. METHODS: The Food Fortification Initiative database was used to identify countries with mandatory fortification policies with folic acid added to cereal grains. We examined the status of FAP SBA prevention assuming mandatory folic acid fortification at 200 mcg/day of folic acid protects against FAP SBA and reduces their prevalence to a minimum achievable rate of 0.5 cases/1000 live births. RESULTS: Our analysis showed that 61,680 FAP SBA cases were prevented in the year 2020 through mandatory folic acid fortification of cereal grains in 58 countries, translating to 22% prevention of total possible FAP SBA prevention globally. Many countries in Africa, Asia, and Europe are yet to implement fortification. In 2020, 30 years after the MRC study was published, 218,270 preventable FAP SBA cases still occurred globally. CONCLUSION: Global prevention efforts for FAP SBA are inadequate even after three decades of knowledge on their prevention. Universal mandatory fortification of staples should be urgently implemented to prevent thousands of FAP SBA and associated elective terminations, stillbirths, and child mortality.

A tug of war between filament treadmilling and myosin induced contractility generates actin rings.

In most eukaryotic cells, actin filaments assemble into a shell-like actin cortex under the plasma membrane, controlling cellular morphology, mechanics, and signaling. The actin cortex is highly polymorphic, adopting diverse forms such as the ring-like structures found in podosomes, axonal rings, and immune synapses. The biophysical principles that underlie the formation of actin rings and cortices remain unknown. Using a molecular simulation platform called MEDYAN, we discovered that varying the filament treadmilling rate and myosin concentration induces a finite size phase transition in actomyosin network structures. We found that actomyosin networks condense into clusters at low treadmilling rates or high myosin concentrations but form ring-like or cortex-like structures at high treadmilling rates and low myosin concentrations. This mechanism is supported by our corroborating experiments on live T cells, which exhibit ring-like actin networks upon activation by stimulatory antibody. Upon disruption of filament treadmilling or enhancement of myosin activity, the pre-existing actin rings are disrupted into actin clusters or collapse towards the network center respectively. Our analyses suggest that the ring-like actin structure is a preferred state of low mechanical energy, which is, importantly, only reachable at sufficiently high treadmilling rates.

Phase separation in transcription factor dynamics and chromatin organization.

Studies over the past decade have highlighted the key role of liquid-liquid phase separation in cellular organization and function. Dynamic compartmentalization of transcription factors and coactivators by such phase-separated condensates regulates the assembly of transcriptional machinery at genomic loci. Although rapid advances in microscopy have demonstrated the ubiquity of such condensates, a rigorous characterization of the physics of phase separation in transcription remains to be carried out. In this review, we discuss theoretical and experimental evidence for biomolecular condensates as dynamic regulators of transcription. Looking beyond, we highlight functional consequences for transcription factor dynamics and gene expression and discuss potential pitfalls of misclassifying biomolecular condensates as liquid droplets in the absence of a rigorous physical description.

Mechanical Regulation of Transcription: Recent Advances.

Mechanotransduction is the ability of a cell to sense mechanical cues from its microenvironment and convert them into biochemical signals to elicit adaptive transcriptional and other cellular responses. Here, we describe recent advances in the field of mechanical regulation of transcription, highlight mechanical regulation of the epigenome as a key novel aspect of mechanotransduction, and describe recent technological advances that could further elucidate the link between mechanical stimuli and gene expression. In this review, we emphasize the importance of mechanotransduction as one of the governing principles of cancer progression, underscoring the need to conduct further studies of the molecular mechanisms involved in sensing mechanical cues and coordinating transcriptional responses.

An intrinsically disordered region-mediated confinement state contributes to the dynamics and function of transcription factors.

Transcription factors (TFs) regulate gene expression by binding to specific consensus motifs within the local chromatin context. The mechanisms by which TFs navigate the nuclear environment as they search for binding sites remain unclear. Here, we used single-molecule tracking and machine-learning-based classification to directly measure the nuclear mobility of the glucocorticoid receptor (GR) in live cells. We revealed two distinct and dynamic low-mobility populations. One accounts for specific binding to chromatin, while the other represents a confinement state that requires an intrinsically disordered region (IDR), implicated in liquid-liquid condensate subdomains. Further analysis showed that the dwell times of both subpopulations follow a power-law distribution, consistent with a broad distribution of affinities on the GR cistrome and interactome. Together, our data link IDRs with a confinement state that is functionally distinct from specific chromatin binding and modulates the transcriptional output by increasing the local concentration of TFs at specific sites.

Safety and Feasibility of Thoracoscopic Lung Resection for Non-Small-Cell Lung Cancer in Octogenarians.

OBJECTIVE: Octogenarians comprise an increasing proportion of patients presenting with non-small-cell lung cancer (NSCLC). This study examines postoperative morbidity and mortality, and long-term survival in octogenarians undergoing thoracoscopic anatomic lung resection for NSCLC, compared with younger cohorts. METHODS: We conducted a retrospective review of our institutional Society of Thoracic Surgeons General Thoracic Surgery Database of all patients ≥60 years old undergoing elective lobectomy or segmentectomy for pathologic stage I, II, and IIIA NSCLC between 2009 and 2018. Results were compared between octogenarians (n = 71) to 2 younger cohorts of 60- to 69-year-olds (n = 359) and 70- to 79-year-olds (n = 308). Long-term survival among octogenarians was graphically summarized using the Kaplan-Meier method. Cox regression analysis was used to identify preoperative risk factors for mortality. RESULTS: A greater proportion of octogenarians required intensive care unit admission and discharge to extended-care facilities; however, postoperative length of stay was similar between groups. Among postoperative complications, arrhythmia and renal failure were more likely in the older cohort. Compared to the youngest cohort, in-hospital and 30-day mortality were highest among octogenarians. Overall survival among octogenarians at 1, 3, and 5 years was 87.3%, 61.8%, and 50.5%, respectively. On multivariable Cox regression analysis of baseline demographic variables, presence of stroke (hazard ratio [HR] = 28.5, 95% confidence interval [CI]: 6.1 to 132.7, P < 0.001) and coronary artery disease (HR = 2.5, 95% CI: 1.2 to 5.3, P = 0.02) were significant predictors of overall mortality among octogenarians. CONCLUSIONS: Thoracoscopic resection can be performed with favorable early postoperative outcomes among octogenarians. Long-term survival, although comparable to their healthy peers, is worse than those of younger cohorts. Further study into preoperative risk stratification and alternative therapies among octogenarians is needed.

Regurgitant Bicuspid Aortopathy: Is Valve-Sparing Root Replacement Equivalent to Bentall Procedure?

BACKGROUND: Repair of aortic root aneurysms with nonstenotic bicuspid valves (NS-BAVs) is achieved either with valve-sparing root replacement (VSRR) or conventional Bentall procedure (ROOT). Procedural and long-term outcomes comparing these 2 techniques are sparse and need investigation. METHODS: From March 2004 to January 2019, 158 patients with an aortic root aneurysm and NS-BAV underwent VSRR (n = 78, 49.3%) or ROOT (n = 80, 50.6%). VSRR involved optional aortic valve repair (n = 47, 60%), and ROOT was performed with bioprosthetic (81.3%) or mechanical valve replacement (18.7%). Procedural and postoperative outcomes were obtained, and univariate and Kaplan-Meier analyses were performed. RESULTS: VSRR patients were younger (42.7 ± 12.0 years of age) than ROOT (54.8 ± 13.6 years of age) (P < .001). Cardiopulmonary bypass (CPB) and cross-clamp duration were longer in VSRR (CPB: 228.0 ± 39.1 minutes; cross-clamp: 200.1 ± 36.2 minutes) compared with ROOT (CPB: 199.5 ± 55 minutes; cross-clamp: 170.3 ± 39.5 minutes) (P < .001). Postoperative stroke, renal failure, pneumonia, and reoperation for bleeding were similar, but postoperative atrial and ventricular arrhythmias was lower in VSRR (15% vs 42%; P < .001). Length of stay and 30-day mortality were similar. At discharge, none had greater than trivial aortic insufficiency. Long-term 10-year survival and incidence of moderate-severe aortic insufficiency, aortic stenosis, and reoperation were equivalent between groups. CONCLUSIONS: Surgery for aortopathy associated with NS-BAV is safe and effective with either VSRR or ROOT. Despite its complexity, VSRR should be considered in the surgical treatment of this population.

A 2019 global update on folic acid-preventable spina bifida and anencephaly.

BACKGROUND: Mandatory folic acid fortification of staples is a proven intervention to prevent spina bifida and anencephaly, two life-threatening and disabling neural tube defects. We estimated the global proportion of folic acid-preventable spina bifida and anencephaly (FAP SBA) prevented through mandatory folic acid fortification of wheat and/or maize flour in 2019. METHODS: Using data from the Global Fortification Data Exchange, we identified countries with mandatory fortification policies that required at least 1.0 ppm folic acid be added to wheat and/or maize flour and had information on percentage of industrially milled flour that is fortified. We built FAP SBA prevention models assuming mandatory folic acid fortification at 200 µg/day of folic acid fully protects against FAP SBA and would lower the prevalence neural tube defects to 0.5 per 1,000 live births. RESULTS: In 2019, 56 countries met our criteria for mandatory folic acid fortification of wheat (n = 56 countries) and/or maize (n = 15 countries) flour and with complete data for our modeling. Overall, our prevention model estimated that 65,380 FAP SBA cases were prevented in 2019 through folic acid fortification of wheat and/or maize flour. We estimated the current global prevention proportion of all preventable FAP SBA cases worldwide to be at 23% of total possible prevention. CONCLUSION: Global prevention efforts for FAP SBA are slow and have stalled. Mandatory fortification should be urgently implemented in all countries to prevent epidemics of FAP SBA, and to achieve health-related Sustainable Development Goals for year 2030 by reducing child mortality due to preventable FAP SBA.

Bcl10 is associated with actin dynamics at the T cell immune synapse.

T cell responses to antigen are initiated by engagement of the T cell receptor (TCR)1, leading to activation of diverse signaling cascades, including an incompletely defined pathway that triggers rapid remodeling of the actin cytoskeleton. Defects in the control of actin dynamics and organization are associated with several human immunodeficiency diseases, emphasizing the importance of cytoskeletal remodeling in the functioning of the adaptive immune system. Here, we investigate the role of the adaptor protein Bcl102 in the control of actin dynamics. Although Bcl10 is primarily known as a component of the pathway connecting the TCR to activation of the NF-κB3 transcription factor, a few studies have implicated Bcl10 in antigen receptor-dependent control of actin polymerization and F-actin-dependent functional responses. However, the role of Bcl10 in the regulation of cytoskeletal dynamics remains largely undefined. To investigate the contribution of Bcl10 in the regulation of TCR-dependent cytoskeletal dynamics, we monitored actin dynamics at the immune synapse of primary murine CD8 effector T cells. Quantification of these dynamics reveals two distinct temporal phases distinguished by differences in speed and directionality. Our results indicate that effector CD8 T cells lacking Bcl10 display faster actin flows and more dynamic lamellipodia, compared to wild-type cells. These studies define a role for Bcl10 in TCR-dependent actin dynamics, emphasizing that Bcl10 has important cytoskeleton-directed functions that are likely independent of its role in transmission of NF-κB -activating signals.

Modeling shows high potential of folic acid-fortified salt to accelerate global prevention of major neural tube defects.

BACKGROUND: We estimated the global proportion of folic acid-preventable spina bifida and anencephaly (FAP SBA) potentially prevented through mandatory double fortification of iodized salt with folic acid. METHODS: Using United Nations Children's Fund (UNICEF) and Global Fortification Data Exchange (GFDx) data sets, we modeled country-specific number of FAP SBA cases prevented annually using (a) current coverage of the salt in households worldwide and (b) expected daily amount of folic acid intake from folic acid-fortified iodized salt. Our evidence-based modeling strategy assumed mandatory folic acid fortification of salt at 20 ppm, and that at 200 µg/day intake of folic acid through fortified salt, should achieve 100% prevention of all FAP SBA in countries. RESULTS: One hundred countries that have data on percent of households consuming iodized salt globally were examined; 55 of them have ≥80% households consuming iodized salt. Our model estimated approximately 180,000 cases of FAP SBA could be prevented in these 100 countries through folic acid-fortified iodized salt, and 150,000 of them would be in countries where ≥80% households consuming iodized salt that can be potentially fortified with folic acid. Salt fortification with folic acid could contribute to the prevention of about 65% global FAP SBA cases annually. CONCLUSIONS: Our evidence-based model shows that there is high potential to prevent FAP SBA using folic acid-fortified iodized salt. Prevention will reach countries where there is a limited reach of centrally processed folic acid-fortified wheat or maize flour. If this intervention is made feasible by the salt industry, it can accelerate the prevention of FAP SBA significantly.

Vacuum-assisted extraction of ilio-caval and right heart masses: A 5-year single center experience.

PURPOSE: Despite paucity of data, there exists growing popularity of catheter-based extraction methods for intravascular thrombi and vegetations. We describe a large single center experience with vacuum-assisted extraction techniques (VAET) for right-sided intravascular and cardiac masses. METHODS: We retrospectively reviewed the perioperative course of patients undergoing VAET between 2014 and 2019. Primary outcomes were survival and freedom from recurrent bacteremia. Procedural success was a composite definition of survival, majority of mass extraction, absence of recurrent bacteremia, and valve function not requiring further intervention during index hospitalization. RESULTS: Of the entire cohort (n = 58), 48% and 52% underwent VAET for vegetations and sterile thrombi, respectively. Of those with positive cultures, the most common organism isolated was Staphylococcus aureus (48%). Preoperative active bacteremia was present in 36% (21/58) and of these patients, 76% (16/21) had neither recurrent nor persistent bacteremia post-op. The majority of masses (67%, 38/58) were debulked with an average reduction in size of 42%. Conversion to open surgery occurred in 3.5% (2/58). Intraoperative and 30-day survival were 98% (57/58) and 90% (28/31), respectively. Overall success was 86% (50/58). The prevalence of moderate/severe tricuspid regurgitation was 37% pre-op and 61% post-op. Average length of intensive care unit and overall hospital stay was 5.6 and 16 days, respectively. CONCLUSIONS: In this single center experience, VAET was conducted safely with a high degree of success and freedom from short-term recurrent bacteremia. This minimally invasive procedure is an attractive alternative to traditional open techniques for removal of right-sided intravascular and cardiac masses.

A 2017 global update on folic acid-preventable spina bifida and anencephaly.

BACKGROUND: Spina bifida and anencephaly are largely preventable birth defects through mandatory folic acid fortification. Our objective was to estimate the proportion of folic acid-preventable spina bifida and anencephaly (FAP SBA) prevented worldwide through mandatory fortification of wheat and/or maize flour with folic acid during the year 2017. METHODS: Using existing data, we identified countries with mandatory fortification policies that added at least 1.0 ppm folic acid to wheat and/or maize flour and had information on percentage of industrially milled flour that is fortified. We assumed mandatory folic acid fortification at 200 µg/day of folic acid fully protects against FAP SBA, reducing the prevalence of spina bifida and anencephaly to 0.5 per 1,000 live births. RESULTS: Overall, 59 countries met our criteria for implementing mandatory folic acid fortification of wheat and/or maize flour in 2017. These countries prevented about 50,270 out of 280,500 FAP SBA births in 2017. Thus, we have only achieved 18% prevention of FAP SBA worldwide. Several countries in Africa and Asia with a high number of FAP SBA-affected births do not have mandatory fortification. CONCLUSION: About 230,000 children unnecessarily developed FAP SBA globally in 2017. There is an urgent need for all countries to implement mandatory folic acid fortification, a proven, safe public health intervention that saves money and prevents infant mortality and disability. Prevention of FAP SBA can play an important role in helping countries to achieve their Sustainable Development Goals for health.