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Smith ME, Chen CT, Gohel CA, Cisbani G, Chen DK, Rezaei K, McCutcheon A, Bazinet RP. Upregulated hepatic lipogenesis from dietary sugars in response to low palmitate feeding supplies brain palmitate. Nat Commun 2024; 15:490. [PMID: 38233416 PMCID: PMC10794264 DOI: 10.1038/s41467-023-44388-4] [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: 03/06/2023] [Accepted: 12/12/2023] [Indexed: 01/19/2024] Open
Abstract
Palmitic acid (PAM) can be provided in the diet or synthesized via de novo lipogenesis (DNL), primarily, from glucose. Preclinical work on the origin of brain PAM during development is scarce and contrasts results in adults. In this work, we use naturally occurring carbon isotope ratios (13C/12C; δ13C) to uncover the origin of brain PAM at postnatal days 0, 10, 21 and 35, and RNA sequencing to identify the pathways involved in maintaining brain PAM, at day 35, in mice fed diets with low, medium, and high PAM from birth. Here we show that DNL from dietary sugars maintains the majority of brain PAM during development and is augmented in mice fed low PAM. Importantly, the upregulation of hepatic DNL genes, in response to low PAM at day 35, demonstrates the presence of a compensatory mechanism to maintain total brain PAM pools compared to the liver; suggesting the importance of brain PAM regulation.
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Affiliation(s)
- Mackenzie E Smith
- Department of Nutritional Sciences, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8, ON, Canada
| | - Chuck T Chen
- Department of Nutritional Sciences, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8, ON, Canada
| | - Chiraag A Gohel
- Department of Biostatistics and Bioinformatics, George Washington University, 950 New Hampshire Ave, NW, Washington, DC, 20052, USA
| | - Giulia Cisbani
- Department of Nutritional Sciences, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8, ON, Canada
| | - Daniel K Chen
- Department of Nutritional Sciences, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8, ON, Canada
| | - Kimia Rezaei
- Department of Nutritional Sciences, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8, ON, Canada
| | - Andrew McCutcheon
- Department of Nutritional Sciences, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8, ON, Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, University of Toronto, 1 King's College Circle, Toronto, M5S 1A8, ON, Canada.
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Metherel AH, Klievik BJ, Cisbani G, Smith ME, Cumberford G, Bazinet RP. Blood and tissue docosahexaenoic acid (DHA, 22:6n-3) turnover rates from Ahiflower® oil are not different than from DHA ethyl ester oil in a diet switch mouse model. Biochim Biophys Acta Mol Cell Biol Lipids 2024; 1869:159422. [PMID: 37977491 DOI: 10.1016/j.bbalip.2023.159422] [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: 08/09/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023]
Abstract
Ahiflower® oil is high in α-linolenic and stearidonic acids, however, tissue/blood docosahexaenoic acid (DHA, 22:6n-3) turnover from dietary Ahiflower oil has not been investigated. In this study, we use compound-specific isotope analysis to determine tissue DHA synthesis/turnover from Ahiflower, flaxseed and DHA oils. Pregnant BALB/c mice (13-17 days) were placed on a 2 % algal DHA oil diet of high carbon-13 content (δ13C) and pups (n = 132) were maintained on the diet until 9 weeks old. Mice were then randomly allocated to a low δ13C-n-3 PUFA diet of either: 1) 4 % Ahiflower oil, 2) 4.35 % flaxseed oil or 3) 1 % fish DHA ethyl ester oil for 1, 3, 7, 14, 30, 60 or 120 days (n = 6). Serum, liver, adipose and brains were collected and DHA levels and δ13C were determined. DHA concentrations were highest (p < 0.05) in the liver and adipose of DHA-fed animals with no diet differences in serum or brain (p > 0.05). Based on the presence or absence of overlapping 95 % C.I.'s, DHA half-lives and synthesis/turnover rates were not different between Ahiflower and DHA diets in the liver, adipose or brain. DHA half-lives and synthesis/turnover rates from flaxseed oil were significantly slower than from the DHA diet in all serum/tissues. These findings suggest that the distinct Ahiflower oil n-3 PUFA composition could support tissue DHA needs at a similar rate to dietary DHA, making it a unique plant-based dietary option for maintaining DHA turnover comparably to dietary DHA.
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Affiliation(s)
- Adam H Metherel
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.
| | - Brinley J Klievik
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Giulia Cisbani
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Mackenzie E Smith
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Greg Cumberford
- Natures Crops International, Kensington, Prince Edward Island, Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
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Cisbani G, Chouinard-Watkins R, Smith ME, Malekanian A, Valenzuela R, Metherel AH, Bazinet RP. Dietary triacetin, but not medium chain triacylglycerides, blunts weight gain in diet-induced rat model of obesity. Lipids 2023; 58:257-270. [PMID: 37997471 DOI: 10.1002/lipd.12381] [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: 07/31/2023] [Revised: 10/16/2023] [Accepted: 10/23/2023] [Indexed: 11/25/2023]
Abstract
Consumption of a Western diet (WD) is known to increase the risk of obesity. Short or medium chain fatty acids influence energy metabolism, and triacetin, a synthetic short chain triacylglyceride, has been shown to lower body fat under normal conditions. This study aimed to investigate if triacetin as part of a WD modifies rat weight and body fat. Male rats were fed a control diet or WD for 8 weeks. At week 8, rats in the WD group were maintained on a WD diet or switched to a WD diet containing 30% energy from medium-chain triacylglyceride (WD-MCT) or triacetin (WD-T) for another 8 weeks. At week 16, rats were euthanized and liver, adipose and blood were collected. Tissue fatty acids (FAs) were quantified by gas chromatography (GC) and hepatic FAs were measured by GC-combustion-isotope ratio mass spectrometry for δ13 C-palmitic acid (PAM)-a novel marker of de novo lipogenesis (DNL). Rats fed WD-T had a body weight not statistically different to the control group, and gained less body weight than rats fed WD alone. Furthermore, WD-T fed rats had a lower fat mass, and lower total liver and plasma FAs compared to the WD group. Rats fed WD-T did not differ from WD in blood ketone or glucose levels, however, had a significantly lower hepatic δ13 C-PAM value than WD fed rats; suggestive of lower DNL. In summary, we show that triacetin has the potential to blunt weight gain and adipose tissue accumulation in a rodent model of obesity, possibly due to a decrease in DNL.
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Affiliation(s)
- Giulia Cisbani
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Raphaël Chouinard-Watkins
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Mackenzie E Smith
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Arezou Malekanian
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Rodrigo Valenzuela
- Nutrition Department, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Adam H Metherel
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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Buszka A, Pytyś A, Colvin D, Włodarczyk J, Wójtowicz T. S-Palmitoylation of Synaptic Proteins in Neuronal Plasticity in Normal and Pathological Brains. Cells 2023; 12:cells12030387. [PMID: 36766729 PMCID: PMC9913408 DOI: 10.3390/cells12030387] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/08/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
Protein lipidation is a common post-translational modification of proteins that plays an important role in human physiology and pathology. One form of protein lipidation, S-palmitoylation, involves the addition of a 16-carbon fatty acid (palmitate) onto proteins. This reversible modification may affect the regulation of protein trafficking and stability in membranes. From multiple recent experimental studies, a picture emerges whereby protein S-palmitoylation is a ubiquitous yet discrete molecular switch enabling the expansion of protein functions and subcellular localization in minutes to hours. Neural tissue is particularly rich in proteins that are regulated by S-palmitoylation. A surge of novel methods of detection of protein lipidation at high resolution allowed us to get better insights into the roles of protein palmitoylation in brain physiology and pathophysiology. In this review, we specifically discuss experimental work devoted to understanding the impact of protein palmitoylation on functional changes in the excitatory and inhibitory synapses associated with neuronal activity and neuronal plasticity. The accumulated evidence also implies a crucial role of S-palmitoylation in learning and memory, and brain disorders associated with impaired cognitive functions.
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Lacombe RJS, Smith ME, Perlman K, Turecki G, Mechawar N, Bazinet RP. Quantitative and carbon isotope ratio analysis of fatty acids isolated from human brain hemispheres. J Neurochem 2023; 164:44-56. [PMID: 36196762 DOI: 10.1111/jnc.15702] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/22/2022] [Accepted: 09/29/2022] [Indexed: 02/04/2023]
Abstract
Our knowledge surrounding the overall fatty acid profile of the adult human brain has been largely limited to extrapolations from brain regions in which the distribution of fatty acids varies. This is especially problematic when modeling brain fatty acid metabolism, therefore, an updated estimate of whole-brain fatty acid concentration is necessitated. Here, we sought to conduct a comprehensive quantitative analysis of fatty acids from entire well-characterized human brain hemispheres (n = 6) provided by the Douglas-Bell Canada Brain Bank. Additionally, exploratory natural abundance carbon isotope ratio (CIR; δ13 C, 13 C/12 C) analysis was performed to assess the origin of brain fatty acids. Brain fatty acid methyl esters (FAMEs) were quantified by gas chromatography (GC)-flame ionization detection and minor n-6 and n-3 polyunsaturated fatty acid pentafluorobenzyl esters by GC-mass spectrometry. Carbon isotope ratio values of identifiable FAMEs were measured by GC-combustion-isotope ratio mass spectrometry. Overall, the most abundant fatty acid in the human brain was oleic acid, followed by stearic acid (STA), palmitic acid (PAM), docosahexaenoic acid (DHA), and arachidonic acid (ARA). Interestingly, cholesterol as well as saturates including PAM and STA were most enriched in 13 C, while PUFAs including DHA and ARA were most depleted in 13 C. These findings suggest a contribution of endogenous synthesis utilizing dietary sugar substrates rich in 13 C, and a combination of marine, animal, and terrestrial PUFA sources more depleted in 13 C, respectively. These results provide novel insights on cerebral fatty acid origin and concentration, the latter serving as a valuable resource for future modeling of fatty acid metabolism in the human brain.
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Affiliation(s)
- R J Scott Lacombe
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Mackenzie E Smith
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Kelly Perlman
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, Quebec, Canada
| | - Gustavo Turecki
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, Quebec, Canada.,Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Naguib Mechawar
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, Quebec, Canada.,Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
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