scholarly journals Determining the Mechanism of Propofol-induced Neurotoxicity

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kyle Burton ◽  
Scott Canfield

Background and Hypothesis: Propofol is an IV anesthetic agent with many clinical applications, including general anesthesia, sedation, delirium, and palliative care. Despite its versatility and effectiveness, Propofol has been shown to have detrimental effects on the vascular interface between the brain and circulation. The Blood-Brain Barrier (BBB) acts as a selective interface that serves to protect the brain from its cerebrovascular network. BBB dysfunction can have lethal complications such as cerebral edema and stroke. Matrix Metalloproteinases (MMP’s), specifically MMP-2 and MMP-9 have been linked to BBB breakdown. Using human induced pluripotent stem cell (IPSC) derived brain microvascular endothelial cells (BMECs), we evaluated the impact of inhibiting MMP-2 on restoring BBB integrity following exposure to Propofol with the intent to reveal the mechanism by which Propofol disrupts the BBB.  We hypothesized that inhibiting MMP-2 would lead to phenotype recovery after exposure to Propofol. Methods: IPSC-differentiated BMECs were treated with MMP inhibitors at varying time points and concentrations relative to exposure to Propofol for 3 hours. Trans-endothelial electrical resistance (TEER) and sodium fluorescein permeability was used to assess BBB structural integrity. A MTT assay was conducted to assess cell viability. Results: Inhibiting MMP-2 did not result in in recovery of BBB integrity following exposure to Propofol as no significant differences were observed in TEER and sodium fluorescein permeability between the Propofol control and Propofol + MMP-2 inhibitor groups. Conclusions & Future Directions: Propofol-induced disruption of BBB integrity does not appear to be through MMP-2 activity. High concentrations of MMP-inhibitor compounds result in increased disruption of BBB tightness and permeability. It is plausible to suspect that Propofol may act through other MMP’s to facilitate BBB break-down, thus future studies should investigate the effects of the other selective MMP inhibitors in their ability to achieve phenotype recovery following exposure to Propofol. 


2021 ◽  
Author(s):  
T. Hang Nghiem-Rao ◽  
Courtney Pfeifer ◽  
Michelle Asuncion ◽  
Joshua Nord ◽  
Daniel Schill ◽  
...  

Abstract Parenteral nutrition-associated cholestasis (PNAC) significantly limits the safety of intravenous parenteral nutrition (PN). Critically ill infants are highly vulnerable to PNAC-related morbidity and mortality, however the impact of hepatic immaturity on PNAC is poorly understood. We examined developmental differences between fetal/infant and adult livers, and used human induced pluripotent stem cell-derived hepatocyte-like cells (iHLC) to gain insights into the contribution of development to altered sterol metabolism and PNAC. We used RNA-sequencing and computational techniques to compare gene expression patterns in human fetal/infant livers, adult liver, and iHLC. We identified distinct gene expression profiles between the human feta/infant livers compared to adult liver, and close resemblance of iHLC to human developing livers. Compared to adult, both developing livers and iHLC had significant downregulation of xenobiotic, bile acid, and fatty acid metabolism; and lower expression of the sterol metabolizing gene ABCG8. When challenged with stigmasterol, a plant sterol found in intravenous soy lipids, lipid accumulation was significantly higher in iHLC compared to adult-derived HepG2 cells. Our findings provide insights into altered bile acid and lipid metabolizing processes in the immature human liver, and support the use of iHLC as a relevant model system of developing liver to study lipid metabolism and PNAC.



mSphere ◽  
2021 ◽  
Author(s):  
Lisa Bauer ◽  
Bas Lendemeijer ◽  
Lonneke Leijten ◽  
Carmen W. E. Embregts ◽  
Barry Rockx ◽  
...  

Infections with the recently emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are often associated with neurological complications. Evidence suggests that SARS-CoV-2 enters the brain via the olfactory nerve; however, SARS-CoV-2 is only rarely detected in the central nervous system of COVID-19 patients.



2015 ◽  
Vol 43 (2) ◽  
pp. 302-307 ◽  
Author(s):  
Aleksandar Rakovic ◽  
Philip Seibler ◽  
Christine Klein

Parkinson disease (PD) is a degenerative disorder of the central nervous system resulting from depletion of dopaminergic neurons and currently remains incurable despite enormous international research efforts. The development of induced pluripotent stem cell (iPSC) technology opened up the unique possibility of studying disease mechanisms in human tissue that was otherwise not accessible, such as the brain. Of particular interest are the monogenetic forms of PD as they closely resemble the more common ‘idiopathic’ PD and, through the mutated protein, provide a clear research target in iPSC-derived neurons. Recessively inherited Parkin and PTEN-induced putative kinase 1 (PINK1) mutations have been investigated in this context and the present review describes the first insights gained from studies in iPSC-derived dopaminergic neurons, which comprise abnormalities in mitochondrial and dopamine homoeostasis, microtubular stability and axonal outgrowth. These new models of PD have a high translational potential that includes the identification of druggable targets, testing of known and novel therapeutic agents in the disease-relevant tissue using well-defined read-outs and potential regenerative approaches.



2020 ◽  
Author(s):  
Kathryn Ufford ◽  
Sabrina Friedline ◽  
Zhaowen Tong ◽  
Vi T. Tang ◽  
Amani S. Dobbs ◽  
...  

SummaryDisease modeling and pharmaceutical testing using cardiomyocytes derived from induced pluripotent stem cell (iPSC-CMs) requires accurate assessment of contractile function. Micropatterning iPSC-CMs on elastic substrates controls cell shape and alignment to enable contractile studies, but the determinants of intrinsic variability in this system have been incompletely characterized. The primary objective of this study was to determine the impact of myofibrillar structure on contractile function in iPSC-CMs. After labeling micropatterned iPSC-CMs with a cell permeant F-actin dye, we imaged both myofibrillar structure and contractile function. Using automated myofibrillar image analysis, we demonstrate that myofibrillar abundance is widely variable among individual iPSC-CMs and strongly correlates with contractile function. This variability is not reduced by subcloning from single iPSCs to reduce genetic heterogeneity, persists with two different iPSC-CM purification methods, and similarly is present for embryonic stem cell-derived cardiomyocytes. This analysis provides compelling evidence that myofibrillar structure should be quantified and controlled for in studies investigating contractile function in iPSC-CMs.



Author(s):  
Yumei Luo ◽  
Mimi Zhang ◽  
Yapei Chen ◽  
Yaoyong Chen ◽  
Detu Zhu

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its rapid international spread has caused the coronavirus disease 2019 (COVID-19) pandemics, which is a global public health crisis. Thus, there is an urgent need to establish biological models to study the pathology of SARS-CoV-2 infection, which not only involves respiratory failure, but also includes dysregulation of other organs and systems, including the brain, heart, liver, intestines, pancreas, kidneys, eyes, and so on. Cellular and organoid models derived from human induced pluripotent stem cells (iPSCs) are ideal tools for in vitro simulation of viral life cycles and drug screening to prevent the reemergence of coronavirus. These iPSC-derived models could recapitulate the functions and physiology of various human cell types and assemble the complex microenvironments similar with those in the human organs; therefore, they can improve the study efficiency of viral infection mechanisms, mimic the natural host-virus interaction, and be suited for long-term experiments. In this review, we focus on the application of in vitro iPSC-derived cellular and organoid models in COVID-19 studies.



2021 ◽  
Author(s):  
Hye Sung Kim ◽  
Yang Xiao ◽  
Xuejing Chen ◽  
Siyu He ◽  
Jongwon Im ◽  
...  

SummaryThe impact of long-term opioid exposure on the embryonic brain is crucial to healthcare due to the surging number of pregnant mothers with an opioid dependency. Current studies on the neuronal effects are limited due to human brain inaccessibility and cross-species differences among animal models. Here, we report a model to assess cell-type specific responses to acute and chronic fentanyl treatment, as well as fentanyl withdrawal, using human induced pluripotent stem cell (hiPSC)-derived midbrain organoids. Single cell mRNA sequencing (25,510 single cells in total) results suggest that chronic fentanyl treatment arrests neuronal subtype specification during early midbrain development and alters the pathways associated with synaptic activities and neuron projection. Acute fentanyl treatment, however, increases dopamine release but does not induce significant changes in gene expressions of cell lineage development. To date, our study is the first unbiased examination of midbrain transcriptomics with synthetic opioid treatment at the single cell level.



PLoS Genetics ◽  
2022 ◽  
Vol 18 (1) ◽  
pp. e1009968
Author(s):  
Geneva M. Cunningham ◽  
Fei Shen ◽  
Xi Wu ◽  
Erica L. Cantor ◽  
Laura Gardner ◽  
...  

Taxane-induced peripheral neuropathy (TIPN) is a devastating survivorship issue for many cancer patients. In addition to its impact on quality of life, this toxicity may lead to dose reductions or treatment discontinuation, adversely impacting survival outcomes and leading to health disparities in African Americans (AA). Our lab has previously identified deleterious mutations in SET-Binding Factor 2 (SBF2) that significantly associated with severe TIPN in AA patients. Here, we demonstrate the impact of SBF2 on taxane-induced neuronal damage using an ex vivo model of SBF2 knockdown of induced pluripotent stem cell-derived sensory neurons. Knockdown of SBF2 exacerbated paclitaxel changes to cell viability and neurite outgrowth while attenuating paclitaxel-induced sodium current inhibition. Our studies identified paclitaxel-induced expression changes specific to mature sensory neurons and revealed candidate genes involved in the exacerbation of paclitaxel-induced phenotypes accompanying SBF2 knockdown. Overall, these findings provide ex vivo support for the impact of SBF2 on the development of TIPN and shed light on the potential pathways involved.



eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Rachel A Battaglia ◽  
Adriana S Beltran ◽  
Samed Delic ◽  
Raluca Dumitru ◽  
Jasmine A Robinson ◽  
...  

Alexander disease (AxD) is a fatal neurodegenerative disorder caused by mutations in glial fibrillary acidic protein (GFAP), which supports the structural integrity of astrocytes. Over 70 GFAP missense mutations cause AxD, but the mechanism linking different mutations to disease-relevant phenotypes remains unknown. We used AxD patient brain tissue and induced pluripotent stem cell (iPSC)-derived astrocytes to investigate the hypothesis that AxD-causing mutations perturb key post-translational modifications (PTMs) on GFAP. Our findings reveal selective phosphorylation of GFAP-Ser13 in patients who died young, independently of the mutation they carried. AxD iPSC-astrocytes accumulated pSer13-GFAP in cytoplasmic aggregates within deep nuclear invaginations, resembling the hallmark Rosenthal fibers observed in vivo. Ser13 phosphorylation facilitated GFAP aggregation and was associated with increased GFAP proteolysis by caspase-6. Furthermore, caspase-6 was selectively expressed in young AxD patients, and correlated with the presence of cleaved GFAP. We reveal a novel PTM signature linking different GFAP mutations in infantile AxD.



2020 ◽  
Author(s):  
Raleigh M. Linville ◽  
Diego Arevalo ◽  
Joanna C. Maressa ◽  
Nan Zhao ◽  
Peter Searson

Abstract Background: During brain development, chemical cues released by developing neurons, cellular signaling with pericytes, and mechanical cues within the brain extracellular matrix (ECM) promote angiogenesis of brain microvascular endothelial cells (BMECs). Angiogenesis is also associated with diseases of the brain due to pathological chemical, cellular, and mechanical signaling. Existing in vitro and in vivo models of brain angiogenesis have key limitations. Methods: Here, we develop a high-throughput in vitro blood-brain barrier (BBB) bead assay of brain angiogenesis utilizing 150 μm diameter beads coated with induced pluripotent stem-cell (iPSC)-derived human BMECs (dhBMECs). After embedding the beads within a 3D matrix, we introduce various chemical cues and extracellular matrix components to explore their effects on angiogenic behavior. Based on the results from the bead assay, we generate a multi-scale model of the human cerebrovasculature within perfusable three-dimensional tissue-engineered blood-brain barrier microvessels.Results: A sprouting phenotype is optimized in confluent monolayers of dhBMECs using chemical treatment with vascular endothelial growth factor (VEGF) and wnt ligands, and the inclusion of pro-angiogenic ECM components. As a proof-of-principle that the bead angiogenesis assay can be applied to study pathological angiogenesis, we show that oxidative stress can exert concentration-dependent effects on angiogenesis. Finally, we demonstrate the formation of a hierarchical microvascular model of the human blood-brain barrier displaying key structural hallmarks. Conclusions: We develop two in vitro models of brain angiogenesis: the BBB bead assay and the tissue-engineered BBB microvessel model. These platforms provide a tool kit for studies of physiological and pathological brain angiogenesis, with key advantages over existing two-dimensional models.



2018 ◽  
Vol 39 (9) ◽  
pp. 1759-1775 ◽  
Author(s):  
Abraham J Al-Ahmad ◽  
Ronak Patel ◽  
Sean P Palecek ◽  
Eric V Shusta

Hyaluronan (HA) constitutes the most abundant extracellular matrix component during brain development, only to become a minor component rapidly after birth and in adulthood to remain in specified regions. HA signaling has been associated with several neurological disorders, yet the impact of HA signaling at the blood–brain barrier (BBB) function remains undocumented. In this study, we investigated the impact of HA on BBB properties using human-induced pluripotent stem cell (iPSC) -derived and primary human and rat BMECs. The impact of HA signaling on developmental and mature BMECs was assessed by measuring changes in TEER, permeability, BMECs markers (GLUT1, tight junction proteins, P-gp) expression and localization, CD44 expression and hyaluronan levels. In general, HA treatment decreased barrier function and reduced P-gp activity with effects being more prominent upon treatment with oligomeric forms of HA (oHA). Such effects were exacerbated when applied during BMEC differentiation phase (considered as developmental BBB). We noted a hyaluronidase activity as well as an increase in CD44 expression during prolonged oxygen–glucose deprivation stress. Inhibition of HA signaling by antibody blockade of CD44 abrogated the detrimental effects of HA treatment. These results suggest the importance of HA signaling through CD44 on BBB properties.



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