trans-mitochondrial-cybrid-generation-from-mtdna-patient-platelets-an

Trans-Mitochondrial Cybrid Generation from mtDNA Patient Platelets: An Efficient Protocol Optimizing Colony Selection and Functional Validation

Trans-mitochondrial cybrid cell line generation represents the gold-standard method for determining pathogenicity by enabling biochemical analyses of a ...

The Children's Hospital of Philadelphia

Mitochondrial GTP (mtGTP)-insensitive mutations in glutamate dehydrogenase (GDH(H454Y)) result in fasting and amino acid-induced hypoglycemia in hyperinsulinemia hyperammonemia (HI/HA). Surprisingly, hypoglycemia may occur in this disorder despite appropriately suppressed insulin. To better understand the islet-specific contribution, transgenic mice expressing the human activating mutation in β-cells (H454Y mice) were characterized in vivo. As in the humans with HI/HA, H454Y mice had fasting hypoglycemia, but plasma insulin concentrations were similar to the controls. Paradoxically, both glucose- and glutamine-stimulated insulin secretion were severely impaired in H454Y mice. Instead, lack of a glucagon response during hypoglycemic clamps identified impaired counterregulation. Moreover, both insulin and glucagon secretion were impaired in perifused islets. Acute pharmacologic inhibition of GDH restored both insulin and glucagon secretion and normalized glucose tolerance in vivo. These studies support the presence of an mtGTP-dependent signal generated via β-cell GDH that inhibits α-cells. As such, in children with activating GDH mutations of HI/HA, this insulin-independent glucagon suppression may contribute importantly to symptomatic hypoglycemia. The identification of a human mutation causing congenital hypoglucagonemic hypoglycemia highlights a central role of the mtGTP-GDH-glucagon axis in glucose homeostasis.

Mitochondrial GTP insensitivity contributes to hypoglycemia in hyperinsulinemia hyperammonemia by inhibiting glucagon release.

Biventricular assist device (BiVAD) support was a strong predictor of early mortality in the Berlin Heart EXCOR Pediatric investigational device exemption (IDE) study (Assess Safety and Probable Benefit of the EXCOR Pediatric Ventricular Assist Device [VAD]). In adults, it has been identified that 5% to 10% of the VAD population is benefited by BiVAD support over left ventricular assist device (LVAD) support. An analysis of the Berlin Heart study cohort was performed to characterize patients supported with BiVAD, examine risk factors of mortality in this group, and identify subsets of patients in whom BiVAD is associated with survival.

Biventricular Berlin Heart EXCOR pediatric use across the united states.

Although there have been tremendous advancements in the care of severe pediatric cardiovascular disease, heart transplantation remains the standard therapy for end-stage heart disease in children. As such, these patients comprise an important and often complex subset of patients in the ICU. The purpose of this article is to review the causes and management of allograft dysfunction and the medications used in the transplant population.

Heart Transplantation-The Pediatric Cardiac Critical Care Perspective.

The purpose of this study was to describe the prevalence, characteristics, and outcomes in pediatric patients with chromosomal anomalies (CA) undergoing orthotopic heart transplantation (OHT).

Cardiac transplantation in children with Down syndrome, Turner syndrome, and other chromosomal anomalies: A multi-institutional outcomes analysis.

Cardiovascular Disease in the Young Council's Science and Clinical Education Lifelong Learning Committee: Year in Review.

Background Packed red blood cell transfusion may improve oxygen content in single-ventricle neonates, but its effect on clinical outcomes after Stage 1 palliation is unknown. Methods and Results Retrospective multicenter analysis of packed red blood cell transfusion exposures in neonates after Stage 1 palliation, excluding those with intraoperative mortality or need for extracorporeal membrane oxygenation. Transfusion practice variability was assessed, and multivariable regression used to identify transfusion risk factors. After propensity score adjustment for severity of illness, clinical outcomes were compared between transfused and nontransfused subjects. Of 396 subjects, 323 (82%) received 930 postoperative red blood cell transfusions. Packed red blood cell volume (median 9-42 mL/kg [<0.0001]), donor exposures (1-2 [<0.0001]), transfusion number (1-3 [<0.0001]), and pretransfusion hemoglobin (12.1-13 g/dL, =0.0049) varied between sites. Cyanosis (=0.02), chest tube output (=0.0003), and delayed sternal closure (=0.0033) increased transfusion risk. Transfusion was associated with prolonged mechanical ventilation (6 [interquartile range 4, 12] versus 3 [1, 5] days, =0.02) and intensive care unit stay (19 [12, 33] versus 9 [6, 19] days, =0.016). When stratified by number of transfusions (0, 1, or >1), duration of mechanical ventilation (3 [1, 5] versus 4 [3, 6] versus 9 [5, 16] days [<0.0001]) and intensive care unit stay (9 [6, 19] versus 13 [8, 25] versus 21 [13, 38] days [<0.0001]) increased for those transfused more than once. Most subjects who died were transfused, though the association with mortality was not significant. Conclusions Packed red blood cell transfusion after Stage 1 palliation is common, and transfusion practice is variable. Transfusion is a significant predictor of longer intensive care unit stay and mechanical ventilation. Further studies to define evidence-based transfusion thresholds are warranted.

Red Blood Cell Transfusion After Stage I Palliation Is Associated With Worse Clinical Outcomes.

Genome-wide association studies (GWAS) have identified genetic links to autoimmune disorders, but lack detail on causal elements. We generated 3D genomic datasets of promoter-focused Capture-C, Hi-C, ATAC-seq, and RNA-seq across 57 human cell types integrated with GWAS of 16 autoimmune traits. These data allowed us to map disease-associated variants to their effector genes and identify impacted cell types more effectively than using 1D genomic features or eQTL approaches. Most variants implicated by 3D cis-regulatory architectures are trait-specific, while half the target genes are shared across multiple disorders and cell types, leading to enrichment of similar biological networks. This indicates complex genetic diversity converges on shared targets, yet unique pathways were identified offering avenues for targeted therapies. We pharmacologically validated squalene synthase, a cholesterol biosynthetic enzyme encoded by the  gene implicated by our approach and eQTL in multiple sclerosis and systemic lupus erythematosus, as a novel immunomodulatory drug target controlling T cell inflammatory cytokine production and aiding B cell antibody production in a human lymphoid organoid model. These data offer a comprehensive resource for understanding gene cis-regulatory mechanisms, and the analyses shed light on how autoimmune-associated variants regulate gene expression, function, and pathology across diverse tissues and cell types.

3D chromatin-based variant-to-gene maps across 57 human cell types reveal the cellular and genetic architecture of autoimmune disease susceptibility.

BACKGROUND: Insight into the genetic basis for many common autoimmune disorders has been uncovered by genome-wide association studies (GWAS), but this alone does not reveal causal variants, effector genes, or the cell types impacted by disease-associated variation. RESULTS: Here, we generate 3D genomic datasets consisting of promoter-focused Capture-C, Hi-C, ATAC-seq, and RNA-seq and integrate this data with GWAS of 16 autoimmune traits to physically map disease-associated variants to the effector genes they likely regulate in 57 human cell types. The majority of variants implicated by these cis-regulatory architectures are trait-specific, but nearly half of the target genes connected to these variants are shared across multiple autoimmune disorders in multiple cell types, leading to enrichment of similar biological networks. While this suggests a high level of genetic diversity and complexity that converges at the level of target gene and cell type, some trait-specific pathways representing potential areas for disease-specific intervention were identified. We pharmacologically validate squalene synthase, a cholesterol biosynthetic enzyme encoded by the FDFT1 gene implicated by our approach and supported by prior eQTL data in multiple sclerosis and systemic lupus erythematosus, as a novel immunomodulatory drug target controlling T cell inflammatory cytokine production and aiding B cell antibody production in a human lymphoid organoid model. CONCLUSIONS: These data represent a comprehensive resource for basic discovery of gene cis-regulatory mechanisms, and the analyses reported reveal mechanisms by which autoimmune-associated variants act to regulate gene expression, function, and pathology across multiple, distinct tissues and cell types.

Immunophenotyping is fundamental to characterizing tissue cellular composition, pathogenic processes, and immune infiltration, yet its accuracy and reproducibility remain constrained by heuristic antibody panel design and manual gating. Here, we present ImmunoPheno, an open-source computational platform that repurposes large-scale single-cell proteo-transcriptomic data to guide immunophenotyping experimental design and analysis. ImmunoPheno integrates existing datasets to automate the design of optimal antibody panels, gating strategies, and cell identity annotation. We used ImmunoPheno to construct a harmonized reference (HICAR) comprising 390 monoclonal antibodies and 93 human immune cell populations. Leveraging this resource, we algorithmically designed minimal panels to isolate rare populations, such as MAIT cells and pDCs, which we validated experimentally. We further demonstrate accurate cell identity annotation across publicly available and newly generated cytometry datasets spanning diverse technologies, including spatial platforms like CODEX. ImmunoPheno complements expert curation and supports continual expansion, providing a scalable framework to enhance the accuracy, reproducibility, and resolution of immunophenotyping.

Article	Year
Mitochondrial GTP insensitivity contributes to hypoglycemia in hyperinsulinemia hyperammonemia by inhibiting glucagon release. Diabetes\| PubMed ID: 25024374	2014
Biventricular Berlin Heart EXCOR pediatric use across the united states. The Annals of thoracic surgery\| PubMed ID: 25704863	2015
Heart Transplantation-The Pediatric Cardiac Critical Care Perspective. Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies\| PubMed ID: 27490596	2016
Cardiac transplantation in children with Down syndrome, Turner syndrome, and other chromosomal anomalies: A multi-institutional outcomes analysis. The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation\| PubMed ID: 29449075	2018
Cardiovascular Disease in the Young Council's Science and Clinical Education Lifelong Learning Committee: Year in Review. Journal of the American Heart Association\| PubMed ID: 30571390	2018
Red Blood Cell Transfusion After Stage I Palliation Is Associated With Worse Clinical Outcomes. Journal of the American Heart Association\| PubMed ID: 32390527	2020
3D chromatin-based variant-to-gene maps across 57 human cell types reveal the cellular and genetic architecture of autoimmune disease susceptibility. medRxiv : the preprint server for health sciences\| PubMed ID: 39185517	2025
3D chromatin-based variant-to-gene maps across 57 human cell types reveal the cellular and genetic architecture of autoimmune disease susceptibility. Genome biology\| PubMed ID: 41361473	2025
ImmunoPheno: A Computational Framework for Data-Driven Design and Analysis of Immunophenotyping Experiments. bioRxiv : the preprint server for biology\| PubMed ID: 41676717	2026

Jarelis Cabrera

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