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Li S, Song H, Sun Y, Sun Y, Zhang H, Gao Z. Inhibition of soluble epoxide hydrolase as a therapeutic approach for blood-brain barrier dysfunction. Biochimie 2024; 223:13-22. [PMID: 38531484 DOI: 10.1016/j.biochi.2024.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 03/20/2024] [Accepted: 03/23/2024] [Indexed: 03/28/2024]
Abstract
The blood-brain barrier (BBB) is a protective semi-permeable structure that regulates the exchange of biomolecules between the peripheral blood and the central nervous system (CNS). Due to its specialized tight junctions and low vesicle trafficking, the BBB strictly limits the paracellular passage and transcellular transport of molecules to maintain the physiological condition of brain tissues. BBB breakdown is associated with many CNS disorders. Soluble epoxide hydrolase (sEH) is a hydrolase enzyme that converts epoxy-fatty acids (EpFAs) to their corresponding diols and is involved in the onset and progression of multiple diseases. EpFAs play a protective role in the central nervous system via preventing neuroinflammation, making sEH a potential therapeutic target for CNS diseases. Recent studies showed that sEH inhibition prevented BBB impairment caused by stroke, hemorrhage, traumatic brain injury, hyperglycemia and sepsis via regulating the expression of tight junctions. In this review, the protective actions of sEH inhibition on BBB and potential mechanisms are summarized, and some important questions that remain to be resolved are also addressed.
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Affiliation(s)
- Shuo Li
- Hebei Province Key Laboratory of Molecular Chemistry for Drug, School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, China
| | - Huijia Song
- Hebei Province Key Laboratory of Molecular Chemistry for Drug, School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, China
| | - Yanping Sun
- Hebei Province Key Laboratory of Molecular Chemistry for Drug, School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, China
| | - Yongjun Sun
- Hebei Province Key Laboratory of Molecular Chemistry for Drug, School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, China
| | - Huimin Zhang
- Hebei Province Key Laboratory of Molecular Chemistry for Drug, School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, China
| | - Zibin Gao
- Hebei Province Key Laboratory of Molecular Chemistry for Drug, School of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, China.
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Yu X, Wang S, Ji Z, Meng J, Mou Y, Wu X, Yang X, Xiong P, Li M, Guo Y. Ferroptosis: An important mechanism of disease mediated by the gut-liver-brain axis. Life Sci 2024; 347:122650. [PMID: 38631669 DOI: 10.1016/j.lfs.2024.122650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/27/2024] [Accepted: 04/13/2024] [Indexed: 04/19/2024]
Abstract
AIMS As a unique iron-dependent non-apoptotic cell death, Ferroptosis is involved in the pathogenesis and development of many human diseases and has become a research hotspot in recent years. However, the regulatory role of ferroptosis in the gut-liver-brain axis has not been elucidated. This paper summarizes the regulatory role of ferroptosis and provides theoretical basis for related research. MATERIALS AND METHODS We searched PubMed, CNKI and Wed of Science databases on ferroptosis mediated gut-liver-brain axis diseases, summarized the regulatory role of ferroptosis on organ axis, and explained the adverse effects of related regulatory effects on various diseases. KEY FINDINGS According to our summary, the main way in which ferroptosis mediates the gut-liver-brain axis is oxidative stress, and the key cross-talk of ferroptosis affecting signaling pathway network is Nrf2/HO-1. However, there were no specific marker between different organ axes mediate by ferroptosis. SIGNIFICANCE Our study illustrates the main ways and key cross-talk of ferroptosis mediating the gut-liver-brain axis, providing a basis for future research.
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Affiliation(s)
- Xinxin Yu
- College of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Shihao Wang
- College of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Zhongjie Ji
- College of Acupuncture and Massage, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Jiaqi Meng
- College of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Yunying Mou
- College of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Xinyi Wu
- College of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Xu Yang
- College of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Panyang Xiong
- College of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China
| | - Mingxia Li
- Nursing School, Shandong University of Traditional Chinese Medicine, Jinan, 250355, Shandong, China
| | - Yinghui Guo
- College of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan 250355, Shandong, China.
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Li Y, Deng H, Zhang H, Yang L, Wang S, Wang H, Zhu J, Li X, Chen X, Lin Y, Li R, Wang G, Li K. Transforming growth factor-β1 protects mechanically injured cortical murine neurons by reducing trauma-induced autophagy and apoptosis. Front Cell Neurosci 2024; 18:1381279. [PMID: 38863498 PMCID: PMC11165077 DOI: 10.3389/fncel.2024.1381279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Accepted: 05/06/2024] [Indexed: 06/13/2024] Open
Abstract
Transforming growth factor β1 (TGF-β1) has a neuroprotective function in traumatic brain injury (TBI) through its anti-inflammatory and immunomodulatory properties. However, the precise mechanisms underlying the neuroprotective actions of TGF-β1 on the cortex require further investigation. In this study, we were aimed to investigate the regulatory function of TGF-β1 on neuronal autophagy and apoptosis using an in vitro primary cortical neuron trauma-injury model. LDH activity was assayed to measure cell viability, and intracellular [Ca2+] was measured using Fluo-4-AM in an in vitro primary cortical neuron trauma-injury model. RNA-sequencing (RNAseq), immunofluorescent staining, transmission electron microscopy (TEM), western blot and CTSD activity detection were employed. We observed significant enrichment of DEGs related to autophagy, apoptosis, and the lysosome pathway in trauma-injured cortical neurons. TEM confirmed the presence of autophagosomes as well as autophagolysosomes. Western blot revealed upregulation of autophagy-related protein light chain 3 (LC3-II/LC3-I), sequestosome 1 (SQSTM1/p62), along with apoptosis-related protein cleaved-caspase 3 in trauma-injured primary cortical neurons. Furthermore, trauma-injured cortical neurons showed an upregulation of lysosomal marker protein (LAMP1) and lysosomal enzyme mature cathepsin D (mCTSD), but a decrease in the activity of CTSD enzyme. These results indicated that apoptosis was up-regulated in trauma- injured cortical neurons at 24 h, accompanied by lysosomal dysfunction and impaired autophagic flux. Notably, TGF-β1 significantly reversed these changes. Our results suggested that TGF-β1 exerted neuroprotective effects on trauma- injured cortical neurons by reducing lysosomal dysfunction, decreasing the accumulation of autophagosomes and autophagolysosomes, and enhancing autophagic flux.
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Affiliation(s)
- Yanlei Li
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
| | - Huixiong Deng
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
| | - Hengyao Zhang
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
| | - Lin Yang
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, Guangdong, China
| | - Shenmiao Wang
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
| | - Haoyang Wang
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
| | - Jiacheng Zhu
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
| | - Xiaoning Li
- Department of Orthopaedics, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiaoxuan Chen
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
| | - Yinhong Lin
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
| | - Rui Li
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
| | - Gefei Wang
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
| | - Kangsheng Li
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, Guangdong, China
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Watanabe S, Souza FDC, Kusumoto I, Shen Q, Nitin N, Lein PJ, Taha AY. Intraperitoneally injected d11-11(12)-epoxyeicosatrienoic acid is rapidly incorporated and esterified within rat plasma and peripheral tissues but not the brain. Prostaglandins Leukot Essent Fatty Acids 2024; 202:102622. [PMID: 38954932 DOI: 10.1016/j.plefa.2024.102622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 05/14/2024] [Accepted: 05/14/2024] [Indexed: 07/04/2024]
Abstract
Epoxyeicosatrienoic acids (EpETrEs) are bioactive lipid mediators of arachidonic acid cytochrome P450 oxidation. In vivo, the free (unbound) form of EpETrEs regulate multiple processes including blood flow, angiogenesis and inflammation resolution. Free EpETrEs are thought to rapidly degrade via soluble epoxide hydrolase (sEH); yet, in many tissues, the majority of EpETrEs are esterified to complex lipids (e.g. phospholipids) suggesting that esterification may play a major role in regulating free, bioactive EpETrE levels. This hypothesis was tested by quantifying the metabolism of intraperitoneally injected free d11-11(12)-Epoxyeicosatrienoic acid (d11-11(12)-EpETrE) in male and female rats. Plasma and tissues (liver, adipose and brain) were obtained 3 to 4 min later and assayed for d11-11(12)-EpETrE and its sEH metabolite, d11-11,12-dihydroxyeicosatrienoic acid (d11-11,12-diHETrE) in both the free and esterified lipid fractions. In both males and females, the majority of injected tracer was recovered in liver followed by plasma and adipose. No tracer was detected in the brain, indicating that brain levels are maintained by endogenous synthesis from precursor fatty acids. In plasma, liver, and adipose, the majority (>54 %) of d11-11(12)-EpETrE was found esterified to phospholipids or neutral lipids (triglycerides and cholesteryl esters). sEH-derived d11-11,12-diHETrE was not detected in plasma or tissues, suggesting negligible conversion within the 3-4 min period post tracer injection. This study shows that esterification is the main pathway regulating free 11(12)-EpETrE levels in vivo.
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Affiliation(s)
- Sho Watanabe
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA; Food Function Analysis Laboratory, Graduate School of Agricultural Science, Tohoku University, Miyagi, 9800845, Japan
| | - Felipe Da Costa Souza
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA
| | - Ibuki Kusumoto
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA; Food Function Analysis Laboratory, Graduate School of Agricultural Science, Tohoku University, Miyagi, 9800845, Japan
| | - Qing Shen
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA
| | - Nitin Nitin
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA; Department of Biological and Agricultural Engineering, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA; MIND Institute, University of California-Davis, 2825 50th Street, Sacramento, CA 95817
| | - Ameer Y Taha
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California, Davis, CA 95616, USA; Center for Neuroscience, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA; West Coast Metabolomics Center, Genome Center, University of California-Davis, Davis, CA 95616, USA.
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Wei C, Li X, Jin Y, Zhang Y, Yuan Q. Does the liver facilitate aging-related cognitive impairment: Conversation between liver and brain during exercise? J Cell Physiol 2024. [PMID: 38704693 DOI: 10.1002/jcp.31287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 03/24/2024] [Accepted: 04/16/2024] [Indexed: 05/07/2024]
Abstract
Liver, an important regulator of metabolic homeostasis, is critical for healthy brain function. In particular, age-related neurodegenerative diseases seriously reduce the quality of life for the elderly. As population aging progresses rapidly, unraveling the mechanisms that effectively delay aging has become critical. Appropriate exercise is reported to improve aging-related cognitive impairment. Whereas current studies focused on exploring the effect of exercise on the aging brain itself, ignoring the persistent effects of peripheral organs on the brain through the blood circulation. The aim of this paper is to summarize the communication and aging processes of the liver and brain and to emphasize the metabolic mechanisms of the liver-brain axis about exercise ameliorating aging-related neurodegenerative diseases. A comprehensive understanding of the potential mechanisms about exercise ameliorating aging is critical for improving adaptation to age-related brain changes and formulating effective interventions against age-related cognitive decline.
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Affiliation(s)
- Changling Wei
- School of Sports Medicine and Health, Chengdu Sport University, Chengdu, Sichuan, China
| | - Xue Li
- School of Sports Medicine and Health, Chengdu Sport University, Chengdu, Sichuan, China
| | - Yu Jin
- School of Sports Medicine and Health, Chengdu Sport University, Chengdu, Sichuan, China
| | - Yuanting Zhang
- School of Sports Medicine and Health, Chengdu Sport University, Chengdu, Sichuan, China
| | - Qiongjia Yuan
- School of Sports Medicine and Health, Chengdu Sport University, Chengdu, Sichuan, China
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Oh YT, Yang J, Stefanovski D, Hammock B, Youn JH. Determinants of Meal-Induced Changes in Circulating FFA Epoxides, Diols, and Diol-to-Epoxide Ratios as Indices of Soluble Epoxide Hydrolase Activity. Int J Mol Sci 2023; 24:17351. [PMID: 38139180 PMCID: PMC10743433 DOI: 10.3390/ijms242417351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/01/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
Soluble epoxide hydrolase (sEH) is an important enzyme for metabolic and cardiovascular health. sEH converts FFA epoxides (EpFAs), many of which are regulators of various cellular processes, to biologically less active diols. In human studies, diol (sEH product) to EpFA (sEH substrate) ratios in plasma or serum have been used as indices of sEH activity. We previously showed these ratios profoundly decreased in rats during acute feeding, possibly reflecting decreases in tissue sEH activities. The present study was designed to test which tissue(s) these measurements in the blood represent and if factors other than sEH activity, such as renal excretion or dietary intake of EpFAs and diols, significantly alter plasma EpFAs, diols, and/or their ratios. The results show that postprandial changes in EpFAs and diols and their ratios in plasma were very similar to those observed in the liver but not in other tissues, suggesting that the liver is largely responsible for these changes in plasma levels. EpFAs and diols were excreted into the urine, but their levels were not significantly altered by feeding, suggesting that renal excretion of EpFAs and diols may not play a major role in postprandial changes in circulating EpFAs, diols, or their ratios. Diet intake had significant impacts on circulating EpFA and diol levels but not on diol-to-EpFA (D-to-E) ratios, suggesting that these ratios, reflecting sEH activities, may not be significantly affected by the availability of sEH substrates (i.e., EpFAs). In conclusion, changes in FFA D-to-E ratios in plasma may reflect those in the liver, which may in turn represent sEH activities in the liver, and they may not be significantly affected by renal excretion or the dietary intake of EpFAs and diols.
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Affiliation(s)
- Young Taek Oh
- Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA;
| | - Jun Yang
- Department of Entomology and Nematology, Comprehensive Cancer Center UCDMC, University of California, Davis, CA 95616, USA; (J.Y.); (B.H.)
| | - Darko Stefanovski
- Department of Biostatistics, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19146, USA;
| | - Bruce Hammock
- Department of Entomology and Nematology, Comprehensive Cancer Center UCDMC, University of California, Davis, CA 95616, USA; (J.Y.); (B.H.)
| | - Jang H. Youn
- Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA;
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Zhang Y, Fang XM. The pan-liver network theory: From traditional chinese medicine to western medicine. CHINESE J PHYSIOL 2023; 66:401-436. [PMID: 38149555 DOI: 10.4103/cjop.cjop-d-22-00131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023] Open
Abstract
In traditional Chinese medicine (TCM), the liver is the "general organ" that is responsible for governing/maintaining the free flow of qi over the entire body and storing blood. According to the classic five elements theory, zang-xiang theory, yin-yang theory, meridians and collaterals theory, and the five-viscera correlation theory, the liver has essential relationships with many extrahepatic organs or tissues, such as the mother-child relationships between the liver and the heart, and the yin-yang and exterior-interior relationships between the liver and the gallbladder. The influences of the liver to the extrahepatic organs or tissues have been well-established when treating the extrahepatic diseases from the perspective of modulating the liver by using the ancient classic prescriptions of TCM and the acupuncture and moxibustion. In modern medicine, as the largest solid organ in the human body, the liver has the typical functions of filtration and storage of blood; metabolism of carbohydrates, fats, proteins, hormones, and foreign chemicals; formation of bile; storage of vitamins and iron; and formation of coagulation factors. The liver also has essential endocrine function, and acts as an immunological organ due to containing the resident immune cells. In the perspective of modern human anatomy, physiology, and pathophysiology, the liver has the organ interactions with the extrahepatic organs or tissues, for example, the gut, pancreas, adipose, skeletal muscle, heart, lung, kidney, brain, spleen, eyes, skin, bone, and sexual organs, through the circulation (including hemodynamics, redox signals, hepatokines, metabolites, and the translocation of microbiota or its products, such as endotoxins), the neural signals, or other forms of pathogenic factors, under normal or diseases status. The organ interactions centered on the liver not only influence the homeostasis of these indicated organs or tissues, but also contribute to the pathogenesis of cardiometabolic diseases (including obesity, type 2 diabetes mellitus, metabolic [dysfunction]-associated fatty liver diseases, and cardio-cerebrovascular diseases), pulmonary diseases, hyperuricemia and gout, chronic kidney disease, and male and female sexual dysfunction. Therefore, based on TCM and modern medicine, the liver has the bidirectional interaction with the extrahepatic organ or tissue, and this established bidirectional interaction system may further interact with another one or more extrahepatic organs/tissues, thus depicting a complex "pan-hepatic network" model. The pan-hepatic network acts as one of the essential mechanisms of homeostasis and the pathogenesis of diseases.
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Affiliation(s)
- Yaxing Zhang
- Department of Physiology; Research Centre of Basic Integrative Medicine, School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong; Issue 12th of Guangxi Apprenticeship Education of Traditional Chinese Medicine (Shi-Cheng Class of Guangxi University of Chinese Medicine), College of Continuing Education, Guangxi University of Chinese Medicine, Nanning, Guangxi, China
| | - Xian-Ming Fang
- Department of Cardiology, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine (Guangxi Hospital of Integrated Chinese Medicine and Western Medicine, Ruikang Clinical Faculty of Guangxi University of Chinese Medicine), Guangxi University of Chinese Medicine, Nanning, Guangxi, China
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Kim D, Horimatsu T, Ogbi M, Goo B, Shi H, Veerapaneni P, Chouhaita R, Moses M, Prasad R, Benson TW, Harb R, Aboud G, Seller H, Haigh S, Fulton DJ, Csányi G, Huo Y, Long X, Coffey P, Lee R, Guha A, Zeldin D, Hwang SH, Hammock BD, Weintraub NL, Kim HW. Hepatocyte-specific disruption of soluble epoxide hydrolase attenuates abdominal aortic aneurysm formation: novel role of the liver in aneurysm pathogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.10.548127. [PMID: 37503031 PMCID: PMC10369876 DOI: 10.1101/2023.07.10.548127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Introduction Inflammation is a key pathogenic feature of abdominal aortic aneurysm (AAA). Soluble epoxide hydrolase (sEH) is a pro-inflammatory enzyme that converts cytochrome P450-derived epoxides of fatty acids to the corresponding diols, and pharmacological inhibition of sEH prevented AAA formation. Both cytochrome P450 enzymes and sEH are highly expressed in the liver. Here, we investigated the role of hepatic sEH in AAA using a selective pharmacological inhibitor of sEH and hepatocyte-specific Ephx2 (which encodes sEH gene) knockout (KO) mice in two models of AAA [angiotensin II (AngII) infusion and calcium chloride (CaCl 2 ) application]. Methods and results sEH expression and activity were strikingly higher in mouse liver compared with aorta and further increased the context of AAA, in conjunction with elevated expression of the transcription factor Sp1 and the epigenetic regulator Jarid1b, which have been reported to positively regulate sEH expression. Pharmacological sEH inhibition, or liver-specific sEH disruption, achieved by crossing sEH floxed mice with albumin-cre mice, prevented AAA formation in both models, concomitant with reduced expression of hepatic sEH as well as complement factor 3 (C3) and serum amyloid A (SAA), liver-derived factors linked to AAA formation. Moreover, sEH antagonism markedly reduced C3 and SAA protein accumulation in the aortic wall. Co-incubation of liver ex vivo with aneurysm-prone aorta resulted in induction of sEH in the liver, concomitant with upregulation of Sp1, Jarid1b, C3 and SAA gene expression, suggesting that the aneurysm-prone aorta secretes factors that activate sEH and downstream inflammatory signaling in the liver. Using an unbiased proteomic approach, we identified a number of dysregulated proteins [ e.g., plastin-2, galectin-3 (gal-3), cathepsin S] released by aneurysm-prone aorta as potential candidate mediators of hepatic sEH induction. Conclusion We provide the first direct evidence of the liver's role in orchestrating AAA via the enzyme sEH. These findings not only provide novel insight into AAA pathogenesis, but they have potentially important implications with regard to developing effective medical therapies for AAA.
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