👤 Edward T O'Leary

Severe burn injuries can cause long-term cognitive impairments, potentially driven by lipid-mediated neuroinflammation in the central nervous system (CNS). The disruption of lipid homeostasis may contribute to neuroinflammatory responses, exacerbating neuronal damage. This study investigates whether acipimox, an anti-lipolytic agent, modulates lipid accumulation and neuroinflammation in the prefrontal cortex following severe burns. Sprague Dawley rats were randomized into four groups: sham vehicle, sham acipimox, burn vehicle, and burn acipimox. A scald injury covering 40-60% of total body surface area was induced, and rats were treated with acipimox (50 mg/kg/day, intraperitoneally) or vehicle for seven days. Lipidomic analysis assessed alterations in lipid profiles, while machine learning (XGBoost) identified key lipid drivers of burn-induced neuroinflammation. Additionally, mRNA expression of inflammatory markers, including interleukin-1β (IL-1β), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and toll-like receptor 4 (TLR4), was quantified to evaluate neuroinflammatory responses. Cytokine-lipid correlations were also examined using Spearman analysis. Lipidomic analysis identified significant alterations in a subset of the 21 lipid classes analyzed, particularly long-chain and very-long-chain fatty acids, including lysophosphatidylethanolamines, lysophosphatidylcholines, phosphatidylglycerols, phosphatidylethanolamines, and triacylglycerols ( These findings suggest that severe burns induce significant lipid dysregulation in the CNS, contributing to neuroinflammation and potential cognitive impairment. By targeting lipolysis, acipimox mitigates lipid accumulation, suppresses inflammatory pathways, and normalizes lipid levels, highlighting a potential therapeutic mechanism. This study establishes a mechanistic link between elevated lipolysis and CNS inflammation following severe burns. Acipimox effectively modulates lipid profiles and reduces neuroinflammation, underscoring its potential for managing burn-induced neurological complications. Further studies are needed to validate these findings and explore clinical applications. Show less

A growing number of patients with tetralogy of Fallot develop left ventricular systolic dysfunction and heart failure, in addition to right ventricular dysfunction. Although cardiac resynchronization therapy (CRT) is an established treatment option, the effect of CRT in this population is still not well defined. This study aimed to investigate the early and late efficacy, survival, and safety of CRT in patients with tetralogy of Fallot. Data were analyzed from an observational, retrospective, multicenter cohort, initiated jointly by the Pediatric and Congenital Electrophysiology Society and the International Society of Adult Congenital Heart Disease. Twelve centers contributed baseline and longitudinal data, including vital status, left ventricular ejection fraction (LVEF), QRS duration, and NYHA functional class. Outcomes were analyzed at early (3 months), intermediate (1 year), and late follow-up (≥2 years) after CRT implantation. A total of 44 patients (40.3±19.2 years) with tetralogy of Fallot and CRT were enrolled. Twenty-nine (65.9%) patients had right ventricular pacing before CRT upgrade. The left ventricular ejection fraction improved from 32% [24%-44%] at baseline to 42% [32%-50%] at early follow-up ( In patients with tetralogy of Fallot treated with CRT consistent improvement in QRS duration, left ventricular ejection fraction, New York Heart Association functional class, and reasonable long-term survival were observed. The findings from this multicenter study support the consideration of CRT in this unique population. Show less

Hypoplastic left heart syndrome (HLHS) with risk of poor outcome has been linked to Whole genome sequencing was performed in 197 probands with HLHS, 43 family members, and 813 controls. Data were filtered for rare, segregating variants in 3 index families comprised of an HLHS proband and relative(s) with cardiomyopathy. Whole genome sequencing data from cases and controls were compared for rare variant burden across 56 cardiomyopathy genes utilizing a weighted burden test approach, accounting for multiple testing using a Bonferroni correction. A pathogenic Whole genome sequencing in multiplex families, proband-parent trios, and case-control cohorts revealed defects in cardiomyopathy-associated genes in patients with HLHS, which may portend impaired functional reserve of the single-ventricle circulation. Show less

Mutations in cardiac myosin binding protein C (MyBP-C, encoded by MYBPC3) are the most common cause of hypertrophic cardiomyopathy (HCM). Most MYBPC3 mutations result in premature termination codons (PTCs) that cause RNA degradation and a reduction of MyBP-C in HCM patient hearts. However, a reduction in MyBP-C has not been consistently observed in MYBPC3-mutant induced pluripotent stem cell cardiomyocytes (iPSCMs). To determine early MYBPC3 mutation effects, we used patient and genome-engineered iPSCMs. iPSCMs with frameshift mutations were compared with iPSCMs with MYBPC3 promoter and translational start site deletions, revealing that allelic loss of function is the primary inciting consequence of mutations causing PTCs. Despite a reduction in wild-type mRNA in all heterozygous iPSCMs, no reduction in MyBP-C protein was observed, indicating protein-level compensation through what we believe is a previously uncharacterized mechanism. Although homozygous mutant iPSCMs exhibited contractile dysregulation, heterozygous mutant iPSCMs had normal contractile function in the context of compensated MyBP-C levels. Agnostic RNA-Seq analysis revealed differential expression in genes involved in protein folding as the only dysregulated gene set. To determine how MYBPC3-mutant iPSCMs achieve compensated MyBP-C levels, sarcomeric protein synthesis and degradation were measured with stable isotope labeling. Heterozygous mutant iPSCMs showed reduced MyBP-C synthesis rates but a slower rate of MyBP-C degradation. These findings indicate that cardiomyocytes have an innate capacity to attain normal MyBP-C stoichiometry despite MYBPC3 allelic loss of function due to truncating mutations. Modulating MyBP-C degradation to maintain MyBP-C protein levels may be a novel treatment approach upstream of contractile dysfunction for HCM. Show less

Truncation mutations in the MYBPC3 gene, encoding for cardiac myosin-binding protein C (MyBP-C), are the leading cause of hypertrophic cardiomyopathy (HCM). Whole heart, fiber and molecular studies demonstrate that MyBP-C is a potent modulator of cardiac contractility, but how these mutations contribute to HCM is unresolved. To readdress whether MYBPC3 truncation mutations result in loss of MyBP-C content and/or the expression of truncated MyBP-C from the mutant allele and determine how these mutations effect myofilament sliding in human myocardium. Septal wall tissue samples were obtained from HCM patients undergoing myectomy (n = 18) and donor controls (n = 8). The HCM samples contained 40% less MyBP-C and reduced levels of MyBP-C phosphorylation, when compared to the donor control samples using quantitative mass spectrometry. These differences occurred in the absence of changes in the stoichiometry of other myofilament proteins or production of truncated MyBP-C from the mutant MYBPC3 allele. The functional impact of MYBPC3 truncation mutations on myofilament sliding was determined using a total internal reflection microscopy (TIRFM) single particle assay. Myosin-thick filaments containing their native complement of MyBP-C, and actin-thin filaments decorated with the troponin/tropomyosin calcium regulatory proteins, were isolated from a subgroup of the HCM (n = 4) and donor (n = 5) heart samples. The maximal sliding velocity of native thin filaments was enhanced within the C-zones of the native thick filaments isolated from the HCM samples, when compared to velocity within the C-zones of thick filaments isolated from the donor samples. Analytical modeling demonstrated that the 40% reduction in MyBP-C content was sufficient to enhance the myofilament sliding velocity, as observed in the TIRFM assay. HCM-causing MYBPC3 truncation mutations result in a loss of MyBP-C content that enhances maximal myofilament sliding velocities, only where MyBP-C is localized within the C-zone. These findings support therapeutic rationale for restoring normal levels of MyBP-C and/or dampening maximal contractile velocities for the treatment of human HCM. Show less

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. It is characterized by highly complex karyotypes with structural and numerical chromosomal alterations. The observed OS-specific characteristics in localization and frequencies of chromosomal breakages strongly implicate a specific set of responsible driver genes or a specific mechanism of fragility induction. In this study, a comprehensive assessment of somatic copy number alterations (SCNAs) was performed in 160 OS samples using whole-genome CytoScan High Density arrays (Affymetrix, Santa Clara, CA). Genes or regions frequently targeted by SCNAs were identified. Breakage analysis revealed OS specific unstable regions in which well-known OS tumor suppressor genes, including TP53, RB1, WWOX, DLG2 and LSAMP are located. Certain genomic features, such as transposable elements and non-B DNA-forming motifs were found to be significantly enriched in the vicinity of chromosomal breakage sites. A complex breakage pattern-chromothripsis-has been suggested as a widespread phenomenon in OS. It was further demonstrated that hyperploidy and in particular chromothripsis were strongly correlated with OS patient clinical outcome. The revealed OS-specific fragility pattern provides novel clues for understanding the biology of OS. Show less

Nedd4-family E3 ubiquitin ligases regulate an array of biologic processes. Autoinhibition maintains these catalytic ligases in an inactive state through several mechanisms. However, although some Nedd4 family members are activated by binding to Nedd4 family-interacting proteins (Ndfips), how binding activates E3 function remains unclear. Our data reveal how these two regulatory processes are linked functionally. In the absence of Ndfip1, the Nedd4 family member Itch can bind an E2 but cannot accept ubiquitin onto its catalytic cysteine. This is because Itch is autoinhibited by an intramolecular interaction between its HECT (homologous to the E6-AP carboxy terminus domain) and two central WW domains. Ndfip1 binds these WW domains to release the HECT, allowing trans-thiolation and Itch catalytic activity. This molecular switch also regulates the closely related family member WWP2. Importantly, multiple PY motifs are required for Ndfip1 to activate Itch, functionally distinguishing Ndfips from single PY-containing substrates. These data establish a novel mechanism for control of the function of a subfamily of Nedd4 E3 ligases at the level of E2-E3 trans-thiolation. Show less

Differentiation of oligodendrocyte progenitor cells (OPCs) into mature oligodendrocytes is regulated by the interplay between extrinsic signals and intrinsic epigenetic determinants. In this study, we analyze the effect that the extracellular ligands sonic hedgehog (Shh) and bone morphogenetic protein 4 (BMP4), have on histone acetylation and gene expression in cultured OPCs. Shh treatment favored the progression toward oligodendrocytes by decreasing histone acetylation and inducing peripheral chromatin condensation. BMP4 treatment, in contrast, inhibited the progression toward oligodendrocytes and favored astrogliogenesis by favoring global histone acetylation and retaining euchromatin. Pharmacological treatment or silencing of histone deacetylase 1 (Hdac1) or histone deacetylase 2 (Hdac2) in OPCs did not affect BMP4-dependent astrogliogenesis, while it prevented Shh-induced oligodendrocyte differentiation and favored the expression of astrocytic genes. Transcriptional profiling of treated OPCs, revealed that BMP4-inhibition of oligodendrocyte differentiation was accompanied by increased levels of Wnt (Tbx3) and Notch-target genes (Jag1, Hes1, Hes5, Hey1, and Hey2), decreased recruitment of Hdac and increased histone acetylation at these loci. Similar upregulation of Notch-target genes and increased histone acetylation were observed in the corpus callosum of mice infused with BMP4 during cuprizone-induced demyelination. We conclude that Shh and Bmp4 differentially regulate histone acetylation and chromatin structure in OPCs and that BMP4 acts as a potent inducer of gene expression, including Notch and Wnt target genes, thereby enhancing the crosstalk among signaling pathways that are known to inhibit myelination and repair. Show less

There are at least five distinct Bardet-Biedl syndrome (BBS) loci, four of which have been mapped: 11q (BBS1), 16q (BBS2), 3p (BBS3), and 15q (BBS4). A comparative study of the three Arab-Bedouin kindreds used to map the BBS2, BBS3, and BBS4 loci suggests that the variability in the number and severity of clinical manifestations, particularly the pattern of polydactyly, reflects chromosome-specific subtypes of BBS [Carmi et al., 1995a; Am J Med Genet 59:199-203]. We describe a Newfoundland kindred of northern European descent and confirm the initial finding of a BBS locus on chromosome 3. However, the "BBS3 phenotype," which includes polydactyly of all four limbs and a progression to morbid obesity, was not observed. Rather, four of the five BBS patients in this family had polydactyly restricted to their feet. The obesity in these patients was reversible with caloric restriction and/or exercise. Mental retardation has been considered a major symptom of BBS. However, formal IQ testing shows that these patients are of average intelligence. Haplotype analysis reduces the BBS3 critical region to a 6-cM interval between D3S1595-D3S1753. Show less