Growing evidence demonstrates that prolonged exposure to general anesthetics induces widespread neuronal cell death followed by long-term memory and learning disability in animal models, raising serious concerns about the safety of obstetric and pediatric anesthesia. Although the underlying mechanisms of increased anesthetic-induced neurotoxicity are complex and just beginning to be understood, our exciting preliminary data point to the role of microRNAs in neurotoxicity. MicroRNAs are endogenous, small, non- coding RNAs that are powerful regulators in normal development and physiology, and diseases through inhibition of target gene expression. Specifically, miR-21 has been shown to decrease apoptosis in varying cell types. Based on our preliminary data and previous reports by others, we hypothesized that the increased mitochondrial fission conferred by downregulated miR-21 contributes to the anesthetic (propofol) neurotoxicity. Propofol is most widely used for sedation and anesthesia in pediatric and obstetric medicine. We propose to utilize gain- and loss-of-function approaches to examine the role of miR-21 in propofol neurotoxicity in mice, translate the findings to humans using stem cell-derived neurons, and investigate the following molecular mechanisms underlying the roles of miR-21 effect: miR-21 targets and suppresses programmed cell death 4 (PDCD4), which can: 1) activate protein kinase B (Akt), 2) decrease mitochondrial fission, delay opening of mitochondrial permeability transition pore (mPTP), and 3) reduce cell death. Downregulated miR-21, upregulated PDCD4, attenuated activation of Akt, and increased mitochondrial fission are likely to contribute to the neurotoxicity conferred by propofol. Our initial exciting data indicate that propofol causes downregulation of miR-21 in stem cell-derived human neurons. In addition, miR-21 knockout increases the vulnerability of mouse developmental neurons and human neurons to propofol exposure. Overexpression of miR-21 attenuated propofol-induced apoptosis in cultured human neurons. Moreover, the reduction of miR-21 is accompanied with a decrease of Akt activation, an increase of mitochondrial fission, and an increase in mPTP opening in human neurons, strongly supporting our hypothesis. We propose the following Specific Aims for the next five years to test our hypotheses: 1) to examine the role of miR-21 in propofol neurotoxicity in mouse brains;2) to determine the role of miR-21 in propofol neurotoxicity in human neurons;and 3) to determine the role of miR-21/PDCD4/mitochondrial fission pathway in propofol neurotoxicity in human neurons and mouse brains. This is a highly clinically relevant study that is innovative and at the forefront in this field. Based on the findings from this proposed study, we can develop more rational neuroprotection strategies, leading to major advances toward assuring the safety of anesthesia in pediatric populations.

Public Health Relevance

Growing evidence demonstrates that prolonged anesthesia with general anesthetics induces widespread neuronal cell death followed by long-term memory and learning disabilities in animal models;seriously questioning the safety of obstetric and pediatric anesthesia. The underlying mechanisms of increased neurotoxicity are complex and just beginning to be understood, and so far, there is no information about microRNA effect in anesthetic neurotoxicity. We propose to utilize gain- and loss-of-function approaches to examine the role of miR-21 in anesthetic neurotoxicity in mice, translate the findings to humans using stem cell-derived neurons, and investigate the novel molecular mechanisms underlying the roles of miR-21 effect. This project is highly clinically relevant and the results will be directly pertinent to a better understanding of the neurotoxic effect of anesthetics. Importantly, the proposed research has the potential of translational application: Identification of the microRNA signaling pathways of anesthetic-induced neurotoxicity will allow targeting molecules that can prevent this effect.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM112696-01
Application #
8670138
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Program Officer
Cole, Alison E
Project Start
2014-05-15
Project End
2019-02-28
Budget Start
2014-05-15
Budget End
2015-02-28
Support Year
1
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Medical College of Wisconsin
Department
Anesthesiology
Type
Schools of Medicine
DUNS #
City
Milwaukee
State
WI
Country
United States
Zip Code
53226
Canfield, Scott G; Zaja, Ivan; Godshaw, Brian et al. (2016) High Glucose Attenuates Anesthetic Cardioprotection in Stem-Cell-Derived Cardiomyocytes: The Role of Reactive Oxygen Species and Mitochondrial Fission. Anesth Analg 122:1269-79
Bosnjak, Zeljko J; Logan, Sarah; Liu, Yanan et al. (2016) Recent Insights Into Molecular Mechanisms of Propofol-Induced Developmental Neurotoxicity: Implications for the Protective Strategies. Anesth Analg 123:1286-1296
Twaroski, Danielle; Bosnjak, Zeljko J; Bai, Xiaowen (2015) MicroRNAs: New Players in Anesthetic-Induced Developmental Neurotoxicity. Pharm Anal Acta 6:357
Twaroski, Danielle M; Yan, Yasheng; Zaja, Ivan et al. (2015) Altered Mitochondrial Dynamics Contributes to Propofol-induced Cell Death in Human Stem Cell-derived Neurons. Anesthesiology 123:1067-83
Kikuchi, Chika; Bienengraeber, Martin; Canfield, Scott et al. (2015) Comparison of Cardiomyocyte Differentiation Potential Between Type 1 Diabetic Donor- and Nondiabetic Donor-Derived Induced Pluripotent Stem Cells. Cell Transplant 24:2491-504
Olson, Jessica M; Yan, Yasheng; Bai, Xiaowen et al. (2015) Up-regulation of microRNA-21 mediates isoflurane-induced protection of cardiomyocytes. Anesthesiology 122:795-805
Zaja, Ivan; Bai, Xiaowen; Liu, Yanan et al. (2014) Cdk1, PKCδ and calcineurin-mediated Drp1 pathway contributes to mitochondrial fission-induced cardiomyocyte death. Biochem Biophys Res Commun 453:710-21
Xu, Xialian; Kriegel, Alison J; Jiao, Xiaoyan et al. (2014) miR-21 in ischemia/reperfusion injury: a double-edged sword? Physiol Genomics 46:789-97
Twaroski, Danielle M; Yan, Yasheng; Olson, Jessica M et al. (2014) Down-regulation of microRNA-21 is involved in the propofol-induced neurotoxicity observed in human stem cell-derived neurons. Anesthesiology 121:786-800