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El-Mergawy R, Chafin L, Ovando-Ricardez JA, Rosas L, Tsai M, Rojas M, Mora AL, Mallampalli RK. FOXK2 targeting by the SCF-E3 ligase subunit FBXO24 for ubiquitin mediated degradation modulates mitochondrial respiration. J Biol Chem 2024; 300:107359. [PMID: 38735474 PMCID: PMC11209018 DOI: 10.1016/j.jbc.2024.107359] [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: 02/05/2024] [Revised: 04/05/2024] [Accepted: 04/30/2024] [Indexed: 05/14/2024] Open
Abstract
FOXK2 is a crucial transcription factor implicated in a wide array of biological activities and yet understanding of its molecular regulation at the level of protein turnover is limited. Here, we identify that FOXK2 undergoes degradation in lung epithelia in the presence of the virulent pathogens Pseudomonas aeruginosa and Klebsiella pneumoniae through ubiquitin-proteasomal processing. FOXK2 through its carboxyl terminus (aa 428-478) binds the Skp-Cullin-F-box ubiquitin E3 ligase subunit FBXO24 that mediates multisite polyubiquitylation of the transcription factor resulting in its nuclear degradation. FOXK2 was detected within the mitochondria and targeted depletion of the transcription factor or cellular expression of FOXK2 mutants devoid of key carboxy terminal domains significantly impaired mitochondrial function. In experimental bacterial pneumonia, Fbxo24 heterozygous mice exhibited preserved mitochondrial function and Foxk2 protein levels compared to WT littermates. The results suggest a new mode of regulatory control of mitochondrial energetics through modulation of FOXK2 cellular abundance.
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Affiliation(s)
- Rabab El-Mergawy
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Lexie Chafin
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Jose A Ovando-Ricardez
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Lorena Rosas
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, USA
| | - MuChun Tsai
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Mauricio Rojas
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Ana L Mora
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Rama K Mallampalli
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, USA.
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Yin X, Yang J, Liu Y, Zhang J, Xin C, Zhao H, Wang W, Shi X, Cui Z, Li G, Zhao C, Liu X. Altered expression of leptin and leptin receptor in the development of immune-mediated aplastic anemia in mice. Exp Ther Med 2019; 18:1047-1056. [PMID: 31316601 PMCID: PMC6601404 DOI: 10.3892/etm.2019.7660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 04/12/2019] [Indexed: 12/24/2022] Open
Abstract
The current study aimed to explore the levels of leptin (LEP) and LEP receptor (LEP-R) on the progression of aplastic anemia (AA) with bone marrow fat conversion. An AA model was developed by infusing C57BL/6 lymph node cells into BALB/c mice. At 0, 3, 6, 9, 12, 15 and 18 days after modeling, routine blood counts, bone marrow biopsy slides, lymphocyte subsets (CD4+ and CD8+ T cells) and cytokine levels [including interleukin (IL)-2, IL-4, IL-5 and interferon-γ] were assessed. LEP and LEP-R levels in peripheral blood serum, mesenchymal stem cells (MSCs) and bone marrow were also analyzed by enzyme-linked immunosorbent assay, polymerase chain reaction and immunohistochemistry. The relevance of LEP, LEP-R and other factors was analyzed by Pearson's correlation analysis. Peripheral pancytopenia (reduced count of white blood cells, red blood cells, hemoglobin and platelets), abnormal immune factor levels and histological changes in bone marrow sections were detected in the AA model mice, suggesting that these mice mimicked the pathological changes commonly observed in AA. In addition, following the establishment of AA, the LEP level was gradually increased and the LEP-R level was reduced in the mice over time (P<0.05). The expression of adipogenic genes, including CCAAT/enhancer-binding protein (C/EBP)α, C/EBPβ and peroxisome proliferator-activated receptor γ, was markedly increased, while the expression of the osteogenic gene runt-related transcription factor 2 was reduced compared with the levels in the control group (P<0.05). Taken together, damage to LEP-R may lead to dysregulation of LEP and the enhancement of MSCs to differentiate into adipocytes, resulting in excessive fat in bone marrow of AA patients.
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Affiliation(s)
- Xiangcong Yin
- Hematology Diagnosis Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Jie Yang
- Hematology Diagnosis Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Yuhua Liu
- Department of Medicine, Qingzhou Traditional Chinese Medicine Hospital, Weifang, Shandong 262500, P.R. China
| | - Jian Zhang
- Department of Hematology, Rizhao People's Hospital, Rizhao, Shandong 276800, P.R. China
| | - Chunlei Xin
- Department of Hematology, Jining No. 1 People's Hospital, Jining, Shandong 272011, P.R. China
| | - Hongguo Zhao
- Department of Hematology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Wei Wang
- Department of Hematology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Xue Shi
- Department of Hematology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Zhongguang Cui
- Department of Hematology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Guanglun Li
- Department of Hematology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Chunting Zhao
- Department of Hematology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Xiaodan Liu
- Department of Hematology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
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