Metabolic Network Analysis Reveals Altered Bile Acid Synthesis and Cholesterol Metabolism in Alzheimer’s Disease

2020 ◽  
Author(s):  
Priyanka Baloni ◽  
Cory C. Funk ◽  
Jingwen Yan ◽  
James T. Yurkovich ◽  
Alexandra Kueider-Paisley ◽  
...  
2020 ◽  
Vol 1 (8) ◽  
pp. 100138
Author(s):  
Priyanka Baloni ◽  
Cory C. Funk ◽  
Jingwen Yan ◽  
James T. Yurkovich ◽  
Alexandra Kueider-Paisley ◽  
...  

2021 ◽  
Vol 22 (14) ◽  
pp. 7451
Author(s):  
Harpreet Kaur ◽  
Drew Seeger ◽  
Svetlana Golovko ◽  
Mikhail Golovko ◽  
Colin Kelly Combs

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by progressive cognitive impairment. It is hypothesized to develop due to the dysfunction of two major proteins, amyloid-β (Aβ) and microtubule-associated protein, tau. Evidence supports the involvement of cholesterol changes in both the generation and deposition of Aβ. This study was performed to better understand the role of liver cholesterol and bile acid metabolism in the pathophysiology of AD. We used male and female wild-type control (C57BL/6J) mice to compare to two well-characterized amyloidosis models of AD, APP/PS1, and AppNL-G-F. Both conjugated and unconjugated primary and secondary bile acids were quantified using UPLC-MS/MS from livers of control and AD mice. We also measured cholesterol and its metabolites and identified changes in levels of proteins associated with bile acid synthesis and signaling. We observed sex differences in liver cholesterol levels accompanied by differences in levels of synthesis intermediates and conjugated and unconjugated liver primary bile acids in both APP/PS1 and AppNL-G-F mice when compared to controls. Our data revealed fundamental deficiencies in cholesterol metabolism and bile acid synthesis in the livers of two different AD mouse lines. These findings strengthen the involvement of liver metabolism in the pathophysiology of AD.


PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Tiangang Li ◽  
John Y. L. Chiang

Bile acids are amphipathic molecules synthesized from cholesterol in the liver. Bile acid synthesis is a major pathway for hepatic cholesterol catabolism. Bile acid synthesis generates bile flow which is important for biliary secretion of free cholesterol, endogenous metabolites, and xenobiotics. Bile acids are biological detergents that facilitate intestinal absorption of lipids and fat-soluble vitamins. Recent studies suggest that bile acids are important metabolic regulators of lipid, glucose, and energy homeostasis. Agonists of peroxisome proliferator-activated receptors (PPARα, PPARγ, PPARδ) regulate lipoprotein metabolism, fatty acid oxidation, glucose homeostasis and inflammation, and therefore are used as anti-diabetic drugs for treatment of dyslipidemia and insulin insistence. Recent studies have shown that activation of PPARαalters bile acid synthesis, conjugation, and transport, and also cholesterol synthesis, absorption and reverse cholesterol transport. This review will focus on the roles of PPARs in the regulation of pathways in bile acid and cholesterol homeostasis, and the therapeutic implications of using PPAR agonists for the treatment of metabolic syndrome.


2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Thomas Q de Aguiar Vallim ◽  
Elizabeth J Tarling ◽  
Hannah Ahn ◽  
Lee R Hagey ◽  
Casey E Romanoski ◽  
...  

Elevated circulating cholesterol levels is a major risk factor for cardiovascular diseases (CVD), and therefore understanding pathways that affect cholesterol metabolism are important for potential treatment of CVD. The major route for cholesterol excretion is through its catabolism to bile acids. Specific bile acids are also potent signaling molecules that modulate metabolic pathways affecting lipid, glucose and bile acid homeostasis. Bile acids are synthesized from cholesterol in the liver, and the key enzymes involved in bile acid synthesis ( Cyp7a1 , Cyp8b1 ) are regulated transcriptionally by the nuclear receptor FXR. We have identified an FXR-regulated pathway upstream of a transcriptional repressor that controls multiple bile acid metabolism genes. We identify MafG as an FXR target gene and show that hepatic MAFG overexpression represses genes of the bile acid synthetic pathway, and modifies the biliary bile acid composition. In contrast, MafG loss-of-function studies cause de-repression of the bile acid genes with concordant changes in biliary bile acid levels. Finally, we identify functional MafG response elements in bile acid metabolism genes using ChIP-Seq analysis. Our studies identify a molecular mechanism for the complex feedback regulation of bile acid synthesis controlled by FXR. The identification of this pathway will likely have important implications in metabolic diseases.


2008 ◽  
Vol 100 (5) ◽  
pp. 937-941 ◽  
Author(s):  
Ariënne de Jong ◽  
Jogchum Plat ◽  
Dieter Lütjohann ◽  
Ronald P. Mensink

Consumption of plant sterol- or stanol-enriched margarines by statin users results in an additional LDL-cholesterol reduction of approximately 10 %, which may be larger than the average decrease of 3–7 % achieved by doubling the statin dose. However, whether this effect persists in the long term is not known. Therefore, we examined in patients already on stable statin treatment the effects of 85 weeks of plant sterol and stanol ester consumption on the serum lipoprotein profile, cholesterol metabolism, and bile acid synthesis. For this, a double-blind randomised trial was designed in which fifty-four patients consumed a control margarine with no added plant sterols or stanols for 5 weeks (run-in period). For the next 85 weeks, seventeen subjects continued with the control margarine and the other two groups with either a plant sterol (n18) or plant stanol (n19) (2·5 g/d each) ester-enriched margarine. Blood was sampled at the end of the run-in period and every 20 weeks during the intervention period. Compared with the control group, plant sterol and stanol ester consumption reduced LDL-cholesterol by 0·28 mmol/l (or 8·7 %;P = 0·08) and 0·42 mmol/l (13·1 %;P = 0·006) respectively after 85 weeks. No effects were found on plasma concentrations of oxysterols or 7α-hydroxy-4-cholesten-3-one, a bile acid synthesis marker. We conclude that long-term consumption of both plant sterol and stanol esters effectively lowered LDL-cholesterol concentrations in statin users.


2019 ◽  
Author(s):  
Priyanka Baloni ◽  
Cory C. Funk ◽  
Jingwen Yan ◽  
James T. Yurkovich ◽  
Alexandra Kueider-Paisley ◽  
...  

AbstractAlzheimer’s disease (AD) is the leading cause of dementia, with metabolic dysfunction seen years before the emergence of clinical symptoms. Increasing evidence suggests a role for primary and secondary bile acids, the end-product of cholesterol metabolism, influencing pathophysiology in AD. In this study, we analyzed transcriptomes from 2114 post-mortem brain samples from three independent cohorts and identified that the genes involved in alternative bile acid synthesis pathway was expressed in brain compared to the classical pathway. These results were supported by targeted metabolomic analysis of primary and secondary bile acids measured from post-mortem brain samples of 111 individuals. We reconstructed brain region-specific metabolic networks using data from three independent cohorts to assess the role of bile acid metabolism in AD pathophysiology. Our metabolic network analysis suggested that taurine transport, bile acid synthesis and cholesterol metabolism differed in AD and cognitively normal individuals. Using the brain transcriptional regulatory network, we identified putative transcription factors regulating these metabolic genes and influencing altered metabolism in AD. Intriguingly, we find bile acids from the brain metabolomics whose synthesis cannot be explained by enzymes we find in the brain, suggesting they may originate from an external source such as the gut microbiome. These findings motivate further research into bile acid metabolism and transport in AD to elucidate their possible connection to cognitive decline.


2020 ◽  
Vol 117 (28) ◽  
pp. 16492-16499
Author(s):  
Elisa Manieri ◽  
Cintia Folgueira ◽  
María Elena Rodríguez ◽  
Luis Leiva-Vega ◽  
Laura Esteban-Lafuente ◽  
...  

Metabolic stress causes activation of the cJun NH2-terminal kinase (JNK) signal transduction pathway. It is established that one consequence of JNK activation is the development of insulin resistance and hepatic steatosis through inhibition of the transcription factor PPARα. Indeed, JNK1/2 deficiency in hepatocytes protects against the development of steatosis, suggesting that JNK inhibition represents a possible treatment for this disease. However, the long-term consequences of JNK inhibition have not been evaluated. Here we demonstrate that hepatic JNK controls bile acid production. We found that hepatic JNK deficiency alters cholesterol metabolism and bile acid synthesis, conjugation, and transport, resulting in cholestasis, increased cholangiocyte proliferation, and intrahepatic cholangiocarcinoma. Gene ablation studies confirmed that PPARα mediated these effects of JNK in hepatocytes. This analysis highlights potential consequences of long-term use of JNK inhibitors for the treatment of metabolic syndrome.


Author(s):  
Yu. O. Shulpekova ◽  
P. E. Tkachenko ◽  
E. N. Shirokova ◽  
I. V. Damulin

Aim. A review to highlight the bile acids importance as steroid mediators of nervous system activity and show the nervous system involvement in cholesterol metabolism and bile acids production.Key points. Presence of bile acid membrane and nuclear receptors and their activation role in mediating manifold metabolic processes have been established in various organs and tissues. Bile acid transporters are discovered in CNS. The animal brain under physiological conditions was found to contain about 20 bile acid types of likely innate origin suggested by their high contents; the bile acids spectrum in CNS differs significantly from blood plasma. Clinical and experimental works are conclusive about the CNS bile acids influence on mitochondrial membrane, their antioxidative role and, probably, steroid-mediator involvement in indirect regulation of memory, attention, motor functions and appetite.Conclusion. Bile acids act as pleiotropic signalling molecules affecting various tissues. The presence in CNS of various bile acid synthesis-related receptors and enzymes indicates their value in brain functioning and warrants research into their metabolism.


2000 ◽  
Vol 275 (20) ◽  
pp. 15482-15489 ◽  
Author(s):  
Chundong Yu ◽  
Fen Wang ◽  
Mikio Kan ◽  
Chengliu Jin ◽  
Richard B. Jones ◽  
...  

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