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Bosnjak, Z. J.

Publications and source records attributed to Bosnjak, Z. J..

2 recordsLinked to original sources

Bridging Stem Cell Models and Medicine: Integrated 3D Human Cerebral Organoids and Pediatric Serum Reveal Mechanisms and Biomarkers of Anesthetic-Induced Neurotoxicity

BackgroundGeneral anesthetics have been shown to cause acute pathological changes in the developing brain, including neuronal cell death. These effects contribute to long-term cognitive and behavioral impairments observed in animal models. Epidemiological and prospective clinical studies have also reported associations between early-life exposure to anesthesia and neurodevelopmental deficits in children, raising significant concerns about pediatric anesthesia and highlighting the urgent need to understand the molecular mechanisms and biomarkers of anesthetic-induced developmental neurotoxicity (AIDN) using human-relevant models. MethodsThis study employed human induced pluripotent stem cell-derived cerebral organoids that were exposed to varying doses of anesthetic propofol for 1 to 6 hours, including single and repeated exposures. In parallel, serum samples were collected pre- and post-surgery from pediatric patients under 4 years old (n = 10 per group) who underwent either short (<1 hour) or prolonged anesthesia (>3 hours) at the Childrens Hospital of Wisconsin between September 2018 and October 2019. Pathological changes in organoids were assessed using chemical assays, electron microscopy, and western blotting. Brain injury-related proteins in patient serum were quantified via ELISA. Genome-wide expression profiling was conducted on 18,855 mRNAs and 27,427 lncRNAs in organoids and serum using microarray and bioinformatics. ResultsHigher doses, longer duration, and repeated exposures to propofol led to increased apoptosis in organoids. Six-hour exposure induced autophagy as evidenced by LC3-II elevation and led to dysregulation of 553 mRNAs and 792 lncRNAs in organoids, along with their co-expressed signaling networks, affecting pathways related to synaptic integrity, mitochondrial function, and inflammation. ELISA and serum analysis of pediatric patients (<4 years old) exposed to anesthesia (>3 hours) demonstrated elevated brain cell injury-associated proteins (e.g., increased NSE) and brain cell type-specific gene expression changes. Serum findings corroborated organoid data, identifying 21 mRNAs and 12 lncRNAs that were dysregulated in both models and associated with cell injury, neuronal development, inflammation, and learning deficits. ConclusionsThis study represents the first integrative transcriptomic analysis of AIDN using both 3D human cerebral organoids and pediatric patient serum--two complementary, human-relevant models. By identifying consistently dysregulated coding and non-coding RNAs across both platforms, we provide compelling evidence of shared molecular signatures linked to neuronal injury, inflammation, and neurodevelopmental disruption. These findings offer not only mechanistic insights but also lay the groundwork for the development of minimally invasive biomarkers and future therapeutic strategies. This dual-model approach bridges experimental discovery with clinical relevance, advancing the translational understanding of pediatric anesthetic neurotoxicity and supporting efforts to improve long-term neurological outcomes in vulnerable patient populations.

neuroscience↗

Augmentation of Histone Deacetylase 6 Activity Impairs Mitochondrial Respiratory Complex I in Ischemic/Reperfused Diabetic Hearts

BACKGROUNDDiabetes augments activity of histone deacetylase 6 (HDAC6) and generation of tumor necrosis factor (TNF) and impairs the physiological function of mitochondrial complex I (mCI) which oxidizes reduced nicotinamide adenine dinucleotide (NADH) to nicotinamide adenine dinucleotide to sustain the tricarboxylic acid cycle and {beta}-oxidation. Here we examined how HDAC6 regulates TNF production, mCI activity, mitochondrial morphology and NADH levels, and cardiac function in ischemic/reperfused diabetic hearts. METHODSHDAC6 knockout, streptozotocin-induced type 1 diabetic, and obese type 2 diabetic db/db mice underwent myocardial ischemia/reperfusion injury in vivo or ex vivo in a Langendorff-perfused system. H9c2 cardiomyocytes with and without HDAC6 knockdown were subjected to hypoxia/reoxygenation injury in the presence of high glucose. We compared the activities of HDAC6 and mCI, TNF and mitochondrial NADH levels, mitochondrial morphology, myocardial infarct size, and cardiac function between groups. RESULTSMyocardial ischemia/reperfusion injury and diabetes synergistically augmented myocardial HDCA6 activity, myocardial TNF levels, and mitochondrial fission and inhibited mCI activity. Interestingly, neutralization of TNF with an anti-TNF monoclonal antibody augmented myocardial mCI activity. Importantly, genetic disruption or inhibition of HDAC6 with tubastatin A decreased TNF levels, mitochondrial fission, and myocardial mitochondrial NADH levels in ischemic/reperfused diabetic mice, concomitant with augmented mCI activity, decreased infarct size, and ameliorated cardiac dysfunction. In H9c2 cardiomyocytes cultured in high glucose, hypoxia/reoxygenation augmented HDAC6 activity and TNF levels and decreased mCI activity. These negative effects were blocked by HDAC6 knockdown. CONCLUSIONSAugmenting HDAC6 activity inhibits mCI activity by increasing TNF levels in ischemic/reperfused diabetic hearts. The HDAC6 inhibitor, tubastatin A, has high therapeutic potential for acute myocardial infarction in diabetes. Novelty and SignificanceO_ST_ABSWhat Is Known?C_ST_ABSO_LIIschemic heart disease (IHS) is a leading cause of death globally, and its presence in diabetic patients is a grievous combination, leading to high mortality and heart failure. C_LIO_LIDiabetes impairs assembly of mitochondrial complex I (mCI), complex III dimer, and complex IV monomer into the respiratory chain supercomplexes, resulting in electron leak and the formation of reactive oxygen species (ROS). C_LIO_LIBy oxidizing reduced nicotinamide adenine dinucleotide (NADH) and reducing ubiquinone, mCI physiologically regenerates NAD+ to sustain the tricarboxylic acid cycle and {beta}-oxidation. C_LI What New Information Does This Article Contribute?O_LIMyocardial ischemia/reperfusion injury (MIRI) and diabetes as comorbidities augment myocardial HDCA6 activity and generation of tumor necrosis factor (TNF), which inhibit myocardial mCI activity. C_LIO_LIGenetic disruption of histone deacetylase 6 (HDAC6) decreases mitochondrial NADH levels and augments mCI activity in type 1 diabetic mice undergoing MIRI via decreasing TNF production, leading to decreases in MIRI. C_LIO_LIPretreatment of type 2 diabetic db/db mice with a HDAC6 inhibitor, tubastatin A (TSA), decreases mitochondrial NADH levels and augments mCI activity by decreasing TNF levels, leading to improvements in cardiac function. C_LI Patients with diabetes are more susceptible to MIRI than non-diabetics with greater mortality and resultant heart failure. There is an unmet medical need in diabetic patients for the treatment of IHS. Our biochemical studies find that MIRI and diabetes synergistically augment myocardial HDAC6 activity and generation of TNF, along with cardiac mitochondrial fission and low bioactivity of mCI. Intriguingly, genetic disruption of HDAC6 decreases the MIRI-induced increases in TNF levels, concomitant with augmented mCI activity, decreased myocardial infarct size, and ameliorated cardiac dysfunction in T1D mice. Importantly, treatment of obese T2D db/db mice with TSA reduces the generation of TNF and mitochondrial fission and enhances mCI activity during reperfusion after ischemia. Our isolated heart studies revealed that genetic disruption or pharmacological inhibition of HDAC6 reduces mitochondrial NADH release during ischemia and ameliorates dysfunction of diabetic hearts undergoing MIRI. Furthermore, HDAC6 knockdown in cardiomyocytes blocks high glucose- and exogenous TNF-induced suppression of mCI activity in vitro, implying that HDAC6 knockdown can preserve mCI activity in high glucose and hypoxia/reoxygenation. These results demonstrate that HDAC6 is an important mediator in MIRI and cardiac function in diabetes. Selective inhibition of HDAC6 has high therapeutic potential for acute IHS in diabetes.

pharmacology and toxicology↗