Single-cell investigation of lead toxicity from neurodevelopment to neurodegeneration: Current review and future opportunities.

Human exposure to the metal lead (Pb) is prevalent and associated with adverse neurodevelopmental and neurodegenerative outcomes. Pb disrupts normal brain function by inducing oxidative stress and neuroinflammation, altering cellular metabolism, and displacing essential metals. Prior studies on the molecular impacts of Pb have examined bulk tissues, which collapse information across all cell types, or in targeted cells, which are limited to cell autonomous effects. These approaches are unable to represent the complete biological implications of Pb exposure because the brain is a cooperative network of highly heterogeneous cells, with cellular diversity and proportions shifting throughout development, by brain region, and with disease. New technologies are necessary to investigate whether Pb and other environmental exposures alter cell composition in the brain and whether they cause molecular changes in a cell-type-specific manner. Cutting-edge, single-cell approaches now enable research resolving cell-type-specific effects from bulk tissues. This article reviews existing Pb neurotoxicology studies with genome-wide molecular signatures and provides a path forward for the field to implement single-cell approaches with practical recommendations.

Neuron-Astrocyte Interactions: A Human Perspective.

This chapter explores the intricate interactions between neurons and astrocytes within the nervous system with a particular emphasis on studies conducted in human tissue or with human cells. We specifically explore how neuron-astrocyte interactions relate to processes of cellular development, morphology, migration, synapse formation, and metabolism. These findings enrich our understanding of basic neurobiology and how disruptions in these processes are relevant to human diseases.The study of human neuron-astrocyte interactions is made possible because of transformative in vitro advancements that have facilitated the generation and sustained culture of human neural cells. In addition, the rise of techniques like sequencing at single-cell resolution has enabled the exploration of numerous human cell atlases and their comparisons to other animal model systems. Thus, the innovations outlined in this chapter illuminate the convergence and divergence of neuron-astrocyte interactions across species. As technologies progress, continually more sophisticated in vitro systems will increasingly reflect in vivo environments and deepen our command of neuron-glial interactions in human biology.

Schwann cell-secreted PGE2 promotes sensory neuron excitability during development.

Electrical excitability-the ability to fire and propagate action potentials-is a signature feature of neurons. How neurons become excitable during development and whether excitability is an intrinsic property of neurons remain unclear. Here, we demonstrate that Schwann cells, the most abundant glia in the peripheral nervous system, promote somatosensory neuron excitability during development. We find that Schwann cells secrete prostaglandin E2, which is necessary and sufficient to induce developing somatosensory neurons to express normal levels of genes required for neuronal function, including voltage-gated sodium channels, and to fire action potential trains. Inactivating this signaling pathway in Schwann cells impairs somatosensory neuron maturation, causing multimodal sensory defects that persist into adulthood. Collectively, our studies uncover a neurodevelopmental role for prostaglandin E2 distinct from its established role in inflammation, revealing a cell non-autonomous mechanism by which glia regulate neuronal excitability to enable the development of normal sensory functions.

Interactive Media-Based Approach for an Exception From Informed Consent Trial Involving Patients With Trauma.

Importance: Exception From Informed Consent (EFIC) research requires community consultation (CC) and public disclosure (PD). Traditional methods of conducting CC and PD are slow, expensive, and labor intensive. Objective: To describe the feasibility and reach of a novel interactive, media-based approach to CC and PD and to identify the similarities and differences between trial sites in website views, survey responses, online community forum attendance, and opt-out requests. Design, Setting, and Participants: This survey study analyzed the CC and PD campaigns conducted for the TAP trial (Evaluation of BE1116 in Patients With Traumatic Injury and Acute Major Bleeding to Improve Survival), an EFIC trial of the early administration of prothrombin complex concentrate in patients with trauma. The CC and PD campaigns consisted of social media advertisements, linked websites, community surveys, and online community forums. These activities were coordinated from a central site and approved by a central institutional review board. This study focused on the first 52 of 91 TAP trial sites (level I trauma centers) in the US to have completed their CC and PD campaigns. Community members in the catchment areas of the participating trauma centers were targeted. Data analysis was conducted between October 2023 and February 2024. Exposure: Social media advertisements, surveys, and online community meetings conducted as part of the CC and PD campaign for the TAP trial. Main Outcomes and Measures: Social media campaign reach and engagement, web page views, survey results, online community forum attendance, and opt-out requests. Results: Fifty-two trial sites were approved for participant enrollment. Social media advertisements were displayed 92 million times, reaching 11.8 million individuals. The median (IQR) number of people reached in each location was 210 317 (172 068-276 968). Site-specific websites were viewed 144 197 times (median [IQR] viewings per site, 2984 [1267-4038]). A total of 17 206 fully or partly completed surveys were received, and survey respondents had a median (IQR) age of 40.1 (15-65) years and included 10 444 females (60.7%). Overall, 60.6% survey respondents said they would want to be entered into the trial even if they could not give consent, 87.7% agreed that emergency care research was necessary, and 88.0% agreed that the TAP trial should be conducted in their community. Online community forums were attended by a median (IQR) number of 38 (20-63) people. Four opt-out requests were received. Conclusions and Relevance: The interactive media-based approach to CC and PD for the ongoing TAP trial showed the feasibility and benefits of executing an efficient, coordinated, centrally run series of locally branded and geographically targeted CC and PD campaigns for a large EFIC study.

Executive Summary: The Pediatric Extracorporeal Membrane Oxygenation Anticoagulation CollaborativE (PEACE) Consensus Conference.

OBJECTIVES: To present recommendations and consensus statements with supporting literature for the clinical management of neonates and children supported with extracorporeal membrane oxygenation (ECMO) from the Pediatric ECMO Anticoagulation CollaborativE (PEACE) consensus conference. DATA SOURCES: Systematic review was performed using PubMed, Embase, and Cochrane Library (CENTRAL) databases from January 1988 to May 2021, followed by serial meetings of international, interprofessional experts in the management ECMO for critically ill children. STUDY SELECTION: The management of ECMO anticoagulation for critically ill children. DATA EXTRACTION: Within each of eight subgroup, two authors reviewed all citations independently, with a third independent reviewer resolving any conflicts. DATA SYNTHESIS: A systematic review was conducted using MEDLINE, Embase, and Cochrane Library databases, from January 1988 to May 2021. Each panel developed evidence-based and, when evidence was insufficient, expert-based statements for the clinical management of anticoagulation for children supported with ECMO. These statements were reviewed and ratified by 48 PEACE experts. Consensus was obtained using the Research and Development/UCLA Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method. We developed 23 recommendations, 52 expert consensus statements, and 16 good practice statements covering the management of ECMO anticoagulation in three broad categories: general care and monitoring; perioperative care; and nonprocedural bleeding or thrombosis. Gaps in knowledge and research priorities were identified, along with three research focused good practice statements. CONCLUSIONS: The 91 statements focused on clinical care will form the basis for standardization and future clinical trials.

Prophylactic Transfusion Strategies in Children Supported by Extracorporeal Membrane Oxygenation: The Pediatric Extracorporeal Membrane Oxygenation Anticoagulation CollaborativE Consensus Conference.

OBJECTIVES: To derive systematic-review informed, modified Delphi consensus regarding prophylactic transfusions in neonates and children supported with extracorporeal membrane oxygenation (ECMO) from the Pediatric ECMO Anticoagulation CollaborativE. DATA SOURCES: A structured literature search was performed using PubMed, EMBASE, and Cochrane Library (CENTRAL) databases from January 1988 to May 2020, with an update in May 2021. STUDY SELECTION: Included studies assessed use of prophylactic blood product transfusion in pediatric ECMO. DATA EXTRACTION: Two authors reviewed all citations independently, with a third independent reviewer resolving conflicts. Thirty-three references were used for data extraction and informed recommendations. Evidence tables were constructed using a standardized data extraction form. MEASUREMENTS AND MAIN RESULTS: The evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation system. Forty-eight experts met over 2 years to develop evidence-informed recommendations and, when evidence was lacking, expert-based consensus statements or good practice statements for prophylactic transfusion strategies for children supported with ECMO. A web-based modified Delphi process was used to build consensus via the Research And Development/University of California Appropriateness Method. Consensus was based on a modified Delphi process with agreement defined as greater than 80%. We developed two good practice statements, 4 weak recommendations, and three expert consensus statements. CONCLUSIONS: Despite the frequency with which pediatric ECMO patients are transfused, there is insufficient evidence to formulate evidence-based prophylactic transfusion strategies.

Relevance and ethical issues of diversity equity and inclusion programs, circa 2024-2025.

A recent resolution with approximately 100 signatories entitled "Sunsetting All Diversity, Equity, and Inclusion (DEI) Programs" administered by the American Academy of Dermatology (AAD) sparked controversial debate within the field. Despite the AAD voting against the proposal to eliminate DEI initiatives, many underrepresented medical groups wondered how to move forward and create safe spaces for everyone. We discuss the relevance of DEI programs in today's society and the ethical challenges that may arise. We conclude with actionable recommendations on how organizations can improve their current DEI strategies to ensure they are more inclusive and not perceived as discriminatory.

A 3D Bioprinted Cortical Organoid Platform for Modeling Human Brain Development.

The ability to promote three-dimensional (3D) self-organization of induced pluripotent stem cells into complex tissue structures called organoids presents new opportunities for the field of developmental biology. Brain organoids have been used to investigate principles of neurodevelopment and neuropsychiatric disorders and serve as a drug screening and discovery platform. However, brain organoid cultures are currently limited by a lacking ability to precisely control their extracellular environment. Here, this work employs 3D bioprinting to generate a high-throughput, tunable, and reproducible scaffold for controlling organoid development and patterning. Additionally, this approach supports the coculture of organoids and vascular cells in a custom architecture containing interconnected endothelialized channels. Printing fidelity and mechanical assessments confirm that fabricated scaffolds closely match intended design features and exhibit stiffness values reflective of the developing human brain. Using organoid growth, viability, cytoarchitecture, proliferation, and transcriptomic benchmarks, this work finds that organoids cultured within the bioprinted scaffold long-term are healthy and have expected neuroectodermal differentiation. Lastly, this work confirms that the endothelial cells (ECs) in printed channel structures can migrate toward and infiltrate into the embedded organoids. This work demonstrates a tunable 3D culturing platform that can be used to create more complex and accurate models of human brain development and underlying diseases.

Neural and metabolic dysregulation in PMM2-deficient human in vitro neural models.

Phosphomannomutase 2-congenital disorder of glycosylation (PMM2-CDG) is a rare inborn error of metabolism caused by deficiency of the PMM2 enzyme, which leads to impaired protein glycosylation. While the disorder presents with primarily neurological symptoms, there is limited knowledge about the specific brain-related changes caused by PMM2 deficiency. Here, we demonstrate aberrant neural activity in 2D neuronal networks from PMM2-CDG individuals. Utilizing multi-omics datasets from 3D human cortical organoids (hCOs) derived from PMM2-CDG individuals, we identify widespread decreases in protein glycosylation, highlighting impaired glycosylation as a key pathological feature of PMM2-CDG, as well as impaired mitochondrial structure and abnormal glucose metabolism in PMM2-deficient hCOs, indicating disturbances in energy metabolism. Correlation between PMM2 enzymatic activity in hCOs and symptom severity suggests that the level of PMM2 enzyme function directly influences neurological manifestations. These findings enhance our understanding of specific brain-related perturbations associated with PMM2-CDG, offering insights into the underlying mechanisms and potential directions for therapeutic interventions.

ScISOr-ATAC reveals convergent and divergent splicing and chromatin specificities between matched cell types across cortical regions, evolution, and in Alzheimer's Disease.

Multimodal measurements have become widespread in genomics, however measuring open chromatin accessibility and splicing simultaneously in frozen brain tissues remains unconquered. Hence, we devised Single-Cell-ISOform-RNA sequencing coupled with the Assay-for-Transposase-Accessible-Chromatin (ScISOr-ATAC). We utilized ScISOr-ATAC to assess whether chromatin and splicing alterations in the brain convergently affect the same cell types or divergently different ones. We applied ScISOr-ATAC to three major conditions: comparing (i) the Rhesus macaque (Macaca mulatta) prefrontal cortex (PFC) and visual cortex (VIS), (ii) cross species divergence of Rhesus macaque versus human PFC, as well as (iii) dysregulation in Alzheimer's disease in human PFC. We found that among cortical-layer biased excitatory neuron subtypes, splicing is highly brain-region specific for L3-5/L6 IT_RORB neurons, moderately specific in L2-3 IT_CUX2.RORB neurons and unspecific in L2-3 IT_CUX2 neurons. In contrast, at the chromatin level, L2-3 IT_CUX2.RORB neurons show the highest brain-region specificity compared to other subtypes. Likewise, when comparing human and macaque PFC, strong evolutionary divergence on one molecular modality does not necessarily imply strong such divergence on another molecular level in the same cell type. Finally, in Alzheimer's disease, oligodendrocytes show convergently high dysregulation in both chromatin and splicing. However, chromatin and splicing dysregulation most strongly affect distinct oligodendrocyte subtypes. Overall, these results indicate that chromatin and splicing can show convergent or divergent results depending on the performed comparison, justifying the need for their concurrent measurement to investigate complex systems. Taken together, ScISOr-ATAC allows for the characterization of single-cell splicing and chromatin patterns and the comparison of sample groups in frozen brain samples.

Gliomas: a reflection of temporal gliogenic principles.

The hijacking of early developmental programs is a canonical feature of gliomas where neoplastic cells resemble neurodevelopmental lineages and possess mechanisms of stem cell resilience. Given these parallels, uncovering how and when in developmental time gliomagenesis intersects with normal trajectories can greatly inform our understanding of tumor biology. Here, we review how elapsing time impacts the developmental principles of astrocyte (AS) and oligodendrocyte (OL) lineages, and how these same temporal programs are replicated, distorted, or circumvented in pathological settings such as gliomas. Additionally, we discuss how normal gliogenic processes can inform our understanding of the temporal progression of gliomagenesis, including when in developmental time gliomas originate, thrive, and can be pushed towards upon therapeutic coercion.

Sexually transmitted infections and HIV in ophthalmology.

The ocular and periocular manifestations of sexually transmitted infections are heterogeneous in etiology, manifestations, and complications. Etiologic agents include bacteria, viruses, parasites, and protozoa, which are most frequently transmitted via direct ocular contact with an active lesion or infected bodily fluid, autoinoculation, or dissemination from a distant site. Vertical transmission most commonly occurs perinatally during vaginal delivery. The complications of ophthalmia neonatorum can be severe, with the potential for permanent blindness or life-threatening systemic involvement if untreated. Clinical features, diagnostic modalities, and therapeutic regimens vary based on etiology and are summarized in this review. Prompt diagnosis is imperative, given the severe sequelae that may result from ocular involvement in these infections, including permanent vision loss. A multidisciplinary approach, involving both ophthalmology and dermatology, to diagnosis and management is essential to mitigate the risk of morbidity associated with sexually transmitted infections resulting in eye disease.

Sexually Transmitted Infections and HIV in Ophthalmology.

The ocular and periocular manifestations of sexually transmitted infections (STIs) are heterogeneous in etiology, manifestations, and complications. Etiologic agents include bacteria, viruses, parasites, and protozoa, which are most frequently transmitted via direct ocular contact with an active lesion or infected bodily fluid, autoinoculation, or dissemination from a distant site. Vertical transmission most commonly occurs perinatally during vaginal delivery. The complications of ophthalmia neonatorum can be severe with the potential for permanent blindness or life-threatening systemic involvement if untreated. Clinical features, diagnostic modalities, and therapeutic regimens vary based on etiology and are summarized in this review. Prompt diagnosis is imperative, given the severe sequelae that may result from ocular involvement in these infections, including permanent vision loss. A multidisciplinary approach, involving both ophthalmology and dermatology, to diagnosis and management is essential to mitigate the risk of morbidity associated with STIs resulting in eye disease.