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Persson SMT, Casselbrant A, Alarai A, Elebring E, Fändriks L, Wallenius V. Role of FFAR3 in ketone body regulated glucagon-like peptide 1 secretion. Biochem Biophys Rep 2024; 39:101749. [PMID: 38910871 PMCID: PMC11192792 DOI: 10.1016/j.bbrep.2024.101749] [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: 04/29/2024] [Revised: 05/23/2024] [Accepted: 06/03/2024] [Indexed: 06/25/2024] Open
Abstract
Background Roux-en-Y gastric bypass (RYGB) is an effective treatment for obesity, resulting in long-term weight loss and rapid remission of type 2 diabetes mellitus. Improved glucagon-like peptide 1 (GLP-1) levels is one factor that contributes to the positive effects. Prior to RYGB, GLP-1 response is blunted which can be attributed to intestinal ketogenesis. Intestinal produced ketone bodies inhibit GLP-1 secretion in enteroendocrine cells via an unidentified G-protein coupled receptors (GPCRs). A possible class of GPCRs through which ketone bodies may reach are the free fatty acid receptors (FFARs) located at the basolateral membrane of enteroendocrine cells. Aim To evaluate FFAR3 expression in enteroendocrine cells of the small intestine under different circumstances, such as diet and bariatric surgery, as well as explore the link between ketone bodies and GLP-1 secretion. Materials and methods FFAR3 and enteroendocrine cell expression was analyzed using Western blot and immunohistochemistry in biopsies from healthy volunteers, obese patients undergoing RYGB and mice. GLUTag cells were used to study GLP-1 secretion and FFAR3 signaling pathways. Results The expression of FFAR3 is markedly influenced by diet, especially high fat diet, which increased FFAR3 protein expression. Lack of substrate such as free fatty acids in the alimentary limb after RYGB, downregulate FFAR3 expression. The number of enteroendocrine cells was affected by diet in the normal weight individuals but not in the subjects with obesity. In GLUTag cells, we show that the ketone bodies exert its blocking effect on GLP-1 secretion via the FFAR3, and the Gαi/o signaling pathway. Conclusion Our findings that ketone bodies via FFAR3 inhibits GLP-1 secretion bring important insight into the pathophysiology of T2D. This highlights the role of FFAR3 as a possible target for future anti-diabetic drugs and treatments.
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Affiliation(s)
- Sara MT. Persson
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Anna Casselbrant
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Aiham Alarai
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- Department of Surgery, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Erik Elebring
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Lars Fändriks
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- Department of Surgery, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Ville Wallenius
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
- Department of Surgery, Region Västra Götaland, Sahlgrenska University Hospital Östra, Gothenburg, Sweden
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Casselbrant A, Elias E, Hallersund P, Elebring E, Cervin J, Fändriks L, Wallenius V. Intestinal Ketogenesis and Permeability. Int J Mol Sci 2024; 25:6555. [PMID: 38928261 PMCID: PMC11204016 DOI: 10.3390/ijms25126555] [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: 04/16/2024] [Revised: 06/10/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
Consumption of a high-fat diet (HFD) has been suggested as a contributing factor behind increased intestinal permeability in obesity, leading to increased plasma levels of microbial endotoxins and, thereby, increased systemic inflammation. We and others have shown that HFD can induce jejunal expression of the ketogenic rate-limiting enzyme mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS). HMGCS is activated via the free fatty acid binding nuclear receptor PPAR-α, and it is a key enzyme in ketone body synthesis that was earlier believed to be expressed exclusively in the liver. The function of intestinal ketogenesis is unknown but has been described in suckling rats and mice pups, possibly in order to allow large molecules, such as immunoglobulins, to pass over the intestinal barrier. Therefore, we hypothesized that ketone bodies could regulate intestinal barrier function, e.g., via regulation of tight junction proteins. The primary aim was to compare the effects of HFD that can induce intestinal ketogenesis to an equicaloric carbohydrate diet on inflammatory responses, nutrition sensing, and intestinal permeability in human jejunal mucosa. Fifteen healthy volunteers receiving a 2-week HFD diet compared to a high-carbohydrate diet were compared. Blood samples and mixed meal tests were performed at the end of each dietary period to examine inflammation markers and postprandial endotoxemia. Jejunal biopsies were assessed for protein expression using Western blotting, immunohistochemistry, and morphometric characteristics of tight junctions by electron microscopy. Functional analyses of permeability and ketogenesis were performed in Caco-2 cells, mice, and human enteroids. Ussing chambers were used to analyze permeability. CRP and ALP values were within normal ranges and postprandial endotoxemia levels were low and did not differ between the two diets. The PPARα receptor was ketone body-dependently reduced after HFD. None of the tight junction proteins studied, nor the basal electrical parameters, were different between the two diets. However, the ketone body inhibitor hymeglusin increased resistance in mucosal biopsies. In addition, the tight junction protein claudin-3 was increased by ketone inhibition in human enteroids. The ketone body β-Hydroxybutyrate (βHB) did not, however, change the mucosal transition of the large-size molecular FD4-probe or LPS in Caco-2 and mouse experiments. We found that PPARα expression was inhibited by the ketone body βHB. As PPARα regulates HMGCS expression, the ketone bodies thus exert negative feedback signaling on their own production. Furthermore, ketone bodies were involved in the regulation of permeability on intestinal mucosal cells in vitro and ex vivo. We were not, however, able to reproduce these effects on intestinal permeability in vivo in humans when comparing two weeks of high-fat with high-carbohydrate diet in healthy volunteers. Further, neither the expression of inflammation markers nor the aggregate tight junction proteins were changed. Thus, it seems that not only HFD but also other factors are needed to permit increased intestinal permeability in vivo. This indicates that the healthy gut can adapt to extremes of macro-nutrients and increased levels of intestinally produced ketone bodies, at least during a shorter dietary challenge.
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Affiliation(s)
- Anna Casselbrant
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, 40530 Gothenburg, Sweden; (E.E.); (P.H.); (L.F.); (V.W.)
| | - Erik Elias
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, 40530 Gothenburg, Sweden; (E.E.); (P.H.); (L.F.); (V.W.)
| | - Peter Hallersund
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, 40530 Gothenburg, Sweden; (E.E.); (P.H.); (L.F.); (V.W.)
| | - Erik Elebring
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, 40530 Gothenburg, Sweden; (E.E.); (P.H.); (L.F.); (V.W.)
| | - Jakob Cervin
- Department of Microbiology and Immunology, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, 40530 Gothenburg, Sweden;
| | - Lars Fändriks
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, 40530 Gothenburg, Sweden; (E.E.); (P.H.); (L.F.); (V.W.)
- Department of Surgery, Region Västra Götaland, Sahlgrenska University Hospital, 41345 Gothenburg, Sweden
| | - Ville Wallenius
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, 40530 Gothenburg, Sweden; (E.E.); (P.H.); (L.F.); (V.W.)
- Department of Surgery, Region Västra Götaland, Sahlgrenska University Hospital, 41345 Gothenburg, Sweden
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Mao H, Wang R, Shao F, Zhao M, Tian D, Xia H, Zhao Y. HMGCS2 serves as a potential biomarker for inhibition of renal clear cell carcinoma growth. Sci Rep 2023; 13:14629. [PMID: 37670031 PMCID: PMC10480187 DOI: 10.1038/s41598-023-41343-7] [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: 02/15/2023] [Accepted: 08/24/2023] [Indexed: 09/07/2023] Open
Abstract
3-Hydroxymethylglutaryl-CoA synthase 2 (HMGCS2) is the rate-limiting enzyme for ketone body synthesis, and most current studies focus on mitochondrial maturation and metabolic reprogramming. The role of HMGCS2 was evaluated in a pan-cancer multi-database using R language, and HMGCS2 was lowly expressed or not differentially expressed in all tumor tissues compared with normal tissues. Correlation analysis of clinical case characteristics, genomic heterogeneity, tumor stemness, and overall survival revealed that HMGCS2 is closely related to clear cell renal cell carcinoma (KIRC). Single-cell sequencing data from normal human kidneys revealed that HMGCS2 is specifically expressed in proximal tubular cells of normal adults. In addition, HMGCS2 is associated with tumor immune infiltration and microenvironment, and KIRC patients with low expression of HMGCS2 have worse prognosis. Finally, the results of cell counting kit 8 assays, colony formation assays, flow cytometry, and Western blot analysis suggested that upregulation of HMGCS2 increased the expression of key tumor suppressor proteins, inhibited the proliferation of clear cell renal cell carcinoma cells and promoted cell apoptosis. In conclusion, HMGCS2 is abnormally expressed in pan-cancer, may play an important role in anti-tumor immunity, and is expected to be a potential tumor prognostic marker, especially in clear cell renal cell carcinoma.
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Affiliation(s)
- Huajie Mao
- Department of Laboratory Medicine, The First Affiliated Hospital of Northwest University, Xi'an No.1 Hospital, Xi'an, 710002, China
| | - Runzhi Wang
- The Ministry of Education Key Laboratory of Laboratory Medical Diagnostics, the College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Fengling Shao
- The Ministry of Education Key Laboratory of Laboratory Medical Diagnostics, the College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Ming Zhao
- Department of Science and Education, The First Affiliated Hospital of Northwest University, Xi'an No.1 Hospital, Xi'an, 710002, China
| | - Dayu Tian
- Department of Laboratory Medicine, The First Affiliated Hospital of Northwest University, Xi'an No.1 Hospital, Xi'an, 710002, China
| | - Hua Xia
- Department of Laboratory Medicine, The First Affiliated Hospital of Northwest University, Xi'an No.1 Hospital, Xi'an, 710002, China
| | - Ya Zhao
- Department of Laboratory Medicine, The First Affiliated Hospital of Northwest University, Xi'an No.1 Hospital, Xi'an, 710002, China.
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Zhang X, Sun C, Wan J, Zhang X, Jia Y, Zhou C. Compartmentalized activities of HMGCS1 control cervical cancer radiosensitivity. Cell Signal 2023; 101:110507. [PMID: 36328117 DOI: 10.1016/j.cellsig.2022.110507] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/15/2022] [Accepted: 10/24/2022] [Indexed: 11/05/2022]
Abstract
The underlying mechanisms by which cellular metabolism affects cervical cancer cell radiosensitivity remain poorly understood. Here, we found that loss of 3-hydroxy-3-methylglutaryl coenzyme A synthase 1 (HMGCS1), a key enzyme catalyzing the conversion of acetoacetyl-CoA to HMG-CoA in the cholesterol biosynthesis pathway, sensitizes the cervical cancer cells to radiation. We observed a compartmentalized cellular distribution of HMGCS1 in nuclei, cytosol, and mitochondria of cervical cancer cells and found that cytosolic HMGCS1 and mitochondrial HMGCS1 contribute together to the regulation of radiosensitivity. Mechanistically, we show that cytosolic HMGCS1 regulates radiosensitivity via manipulating the cholesterol metabolism, while mitochondrial HMGCS1 controls mitochondrial gene expression, thereby sustaining the mitochondrial function of cervical cancer cells. Together, our study identifies HMGCS1 as a novel regulator of radiosensitivty in cervical cancer cells, providing a molecular link between altered cholesterol metabolism, mitochondrial respiration, and radiosensitivity. Thus, targeting HMGCS1 may improve the therapeutic outcome of cervical cancer radiotherapy.
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Affiliation(s)
- Xiaomin Zhang
- Department of Obstetrics and Gynecology, Binzhou Medical University Hospital, Binzhou, Shandong 256603, PR China
| | - Congcong Sun
- Department of Obstetrics and Gynecology, Binzhou Medical University Hospital, Binzhou, Shandong 256603, PR China
| | - Jinliang Wan
- Department of Oncology, Binzhou Medical University Hospital, Binzhou, Shandong 256603, PR China
| | - Xiaoxue Zhang
- Department of Obstetrics and Gynecology, Binzhou Medical University Hospital, Binzhou, Shandong 256603, PR China
| | - Yanhan Jia
- Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China; Radiation Oncology Key Laboratory of Sichuan Province, Chengdu, China.
| | - Chao Zhou
- Department of Obstetrics and Gynecology, Binzhou Medical University Hospital, Binzhou, Shandong 256603, PR China.
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Morphological Adaptation in the Jejunal Mucosa after Iso-Caloric High-Fat versus High-Carbohydrate Diets in Healthy Volunteers: Data from a Randomized Crossover Study. Nutrients 2022; 14:nu14194123. [PMID: 36235775 PMCID: PMC9572503 DOI: 10.3390/nu14194123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/23/2022] [Accepted: 09/29/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND AIMS The conditions for jejunal glucose absorption in healthy subjects have not been thoroughly studied. In this study we investigated differences in the jejunal villi enlargement factor, as well as ultrastructural aspects of the surface enterocytes and mitochondria, comparing 2 weeks of high-carbohydrate (HCD) versus high-fat diets (HFD). We also measured the ketogenesis rate-limiting enzyme 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) in relation to jejunal mitochondria. METHODS A single-centre, randomized, unblinded crossover study in 15 healthy volunteers ingesting strictly controlled equicaloric diets (either HCD or HFD), with 60% energy from the respective source. An enteroscopy was carried out after 2 weeks of each diet and jejunal mucosal biopsies were acquired. Conventional histology, immunofluorescent staining, transmission electron microscopy and confocal microscopy were used. RESULTS The villi did not demonstrate any change in the epithelial enlargement factor. Despite an increased mitosis, there were no changes in apoptotic indices. However, the ultrastructural analysis demonstrated a significant increase in the enlargement factor at the bases of the villi. The mitochondria demonstrated increased amounts of cristae after the HFD. The confocal microscopy revealed increased HMGCS2 per mitochondrial marker at the top of the villi after the HFD compared to the HCD. CONCLUSION There is a morphometric adaption in the jejunal mucosa following the 2-week diets, not only on a histological level, but rather on the ultrastructural level. This study supports the notion that mitochondrial HMGCS2 is regulated by the fat content of the diet and is involved in the expression of monosaccharide transporters.
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