1
|
Liu X, Zhang D, Hu J, Xu S, Xu C, Shen Y. Allograft inflammatory factor 1 is a potential diagnostic, immunological, and prognostic biomarker in pan-cancer. Aging (Albany NY) 2023; 15:2582-2609. [PMID: 37014322 PMCID: PMC10120906 DOI: 10.18632/aging.204631] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/20/2023] [Indexed: 04/05/2023]
Abstract
BACKGROUND Allograft Inflammatory Factor 1 (AIF-1) is a member of the allograft inflammatory factor gene family and plays an essential role in the occurrence and development of malignant tumors. However, little is known about the expression pattern, predictive value, and biological function of AIF-1 across cancers. MATERIALS AND METHODS We first analyzed AIF-1 expression across cancers based on data from public databases. Univariate Cox regression and Kaplan-Meier analyses were used to explore the predictive value of AIF-1 expression in various cancers. Moreover, gene set enrichment analysis (GSEA) was applied to determine the cancer hallmarks associated with AIF-1 expression. Spearman correlation analysis was performed to investigate the association between AIF-1 expression and tumor microenvironment scores, immune cell infiltration, immune-related genes, TMB, MSI, and DNA methyltransferases. RESULTS AIF-1 expression was upregulated in most cancer types and exhibited prognosis-predictive ability. AIF-1 expression was positively correlated with immune infiltrating cells and immune checkpoint-related genes in most cancers. Additionally, the promoter methylation level of AIF-1 was different in distinct tumors. High methylation levels of AIF-1 were associated with a worse prognosis in UCEC and melanoma, whereas they were associated with a better prognosis in GBM, KIRC, OV, and UVM. Finally, we found that AIF-1 was significantly highly expressed in KIRC tissues. Functionally, silencing AIF-1 dramatically decreased proliferation, migration, and invasion abilities. CONCLUSION Our results reveal that AIF-1 acts as a robust tumor biomarker and is closely correlated with tumor immune infiltration. Furthermore, AIF-1 may function as an oncogene and promote tumor progression in KIRC.
Collapse
Affiliation(s)
- Xin Liu
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
| | - Dandan Zhang
- Department of General Surgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
- Jiangxi Key Laboratory of Molecular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
| | - Jianping Hu
- Jiangxi Key Laboratory of Molecular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
- Department of Medical Genetics, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
| | - Sikai Xu
- Department of Medical Genetics, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
| | - Chengyun Xu
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
| | - Yang Shen
- Jiangxi Key Laboratory of Molecular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
- Department of Medical Genetics, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
| |
Collapse
|
2
|
Hellemann E, Walker JL, Lesko MA, Chandrashekarappa DG, Schmidt MC, O’Donnell AF, Durrant JD. Novel mutation in hexokinase 2 confers resistance to 2-deoxyglucose by altering protein dynamics. PLoS Comput Biol 2022; 18:e1009929. [PMID: 35235554 PMCID: PMC8920189 DOI: 10.1371/journal.pcbi.1009929] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 03/14/2022] [Accepted: 02/16/2022] [Indexed: 01/16/2023] Open
Abstract
Glucose is central to many biological processes, serving as an energy source and a building block for biosynthesis. After glucose enters the cell, hexokinases convert it to glucose-6-phosphate (Glc-6P) for use in anaerobic fermentation, aerobic oxidative phosphorylation, and the pentose-phosphate pathway. We here describe a genetic screen in Saccharomyces cerevisiae that generated a novel spontaneous mutation in hexokinase-2, hxk2G238V, that confers resistance to the toxic glucose analog 2-deoxyglucose (2DG). Wild-type hexokinases convert 2DG to 2-deoxyglucose-6-phosphate (2DG-6P), but 2DG-6P cannot support downstream glycolysis, resulting in a cellular starvation-like response. Curiously, though the hxk2G238V mutation encodes a loss-of-function allele, the affected amino acid does not interact directly with bound glucose, 2DG, or ATP. Molecular dynamics simulations suggest that Hxk2G238V impedes sugar binding by altering the protein dynamics of the glucose-binding cleft, as well as the large-scale domain-closure motions required for catalysis. These findings shed new light on Hxk2 dynamics and highlight how allosteric changes can influence catalysis, providing new structural insights into this critical regulator of carbohydrate metabolism. Given that hexokinases are upregulated in some cancers and that 2DG and its derivatives have been studied in anti-cancer trials, the present work also provides insights that may apply to cancer biology and drug resistance. Glucose fuels many of the energy-production processes required for normal cell growth. Before glucose can participate in these processes, it must first be chemically modified by proteins called hexokinases. To better understand how hexokinases modify glucose—and how mutations in hexokinase genes might confer drug resistance—we evolved resistance in yeast to a toxic hexokinase-binding molecule called 2DG. We discovered a mutation in the hexokinase gene that confers 2DG resistance and reduces the protein’s ability to modify glucose. Biochemical analyses and computer simulations of the hexokinase protein suggest that the mutation diminishes glucose binding by altering enzyme flexibility. This work shows how cells can evolve resistance to toxins via only modest changes to protein structures. Furthermore, because cancer-cell hexokinases are particularly active, 2DG has been studied as cancer chemotherapy. Thus, the insights this work provides might also apply to cancer biology.
Collapse
Affiliation(s)
- Erich Hellemann
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jennifer L. Walker
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Mitchell A. Lesko
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Dakshayini G. Chandrashekarappa
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Martin C. Schmidt
- University of Pittsburgh School of Medicine, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Allyson F. O’Donnell
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (AFO); (JDD)
| | - Jacob D. Durrant
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (AFO); (JDD)
| |
Collapse
|
3
|
Novo N, Ferreira P, Medina M. The apoptosis-inducing factor family: Moonlighting proteins in the crosstalk between mitochondria and nuclei. IUBMB Life 2021; 73:568-581. [PMID: 33035389 DOI: 10.1002/iub.2390] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 09/01/2020] [Accepted: 09/09/2020] [Indexed: 12/13/2022]
Abstract
In Homo sapiens, the apoptosis-inducing factor (AIF) family is represented by three different proteins, known as AIF, AMID and AIFL, that have in common the mitochondrial localisation in healthy cells, the presence of FAD- and NADH-dependent domains involved in an -albeit yet not well understood- oxidoreductase function and their capability to induce programmed cell death. AIF is the best characterised family member, while the information about AMID and AIFL is much scarcer. Nonetheless, available data support different roles as well as mechanisms of action of their particular apoptogenic and redox domains regarding both pro-apoptotic and anti-apoptotic activities. Moreover, diverse cellular functions, to date far from fully clarified, are envisaged for the transcripts corresponding to these three proteins. Here, we review the so far available knowledge on the moonlighting human AIF family from their molecular properties to their relevance in health and disease, through the evaluation of their potential cell death and redox functions in their different subcellular locations. This picture emerging from the current knowledge of the AIF family envisages its contribution to regulate signalling and transcription machineries in the crosstalk among mitochondria, the cytoplasm and the nucleus.
Collapse
Affiliation(s)
- Nerea Novo
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences, University of Zaragoza, Zaragoza, Spain
- Institute of Biocomputation and Physics of Complex Systems (BIFI-IQFR and CBsC-CSIC Joint Units, University of Zaragoza, Zaragoza, Spain
| | - Patricia Ferreira
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences, University of Zaragoza, Zaragoza, Spain
- Institute of Biocomputation and Physics of Complex Systems (BIFI-IQFR and CBsC-CSIC Joint Units, University of Zaragoza, Zaragoza, Spain
| | - Milagros Medina
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences, University of Zaragoza, Zaragoza, Spain
- Institute of Biocomputation and Physics of Complex Systems (BIFI-IQFR and CBsC-CSIC Joint Units, University of Zaragoza, Zaragoza, Spain
| |
Collapse
|
4
|
Letkovska K, Babal P, Cierna Z, Schmidtova S, Liskova V, Kalavska K, Miskovska V, Horak S, Rejlekova K, Chovanec M, Mardiak J, Janega P, Mego M. Prognostic Value of Apoptosis-Inducing Factor (AIF) in Germ Cell Tumors. Cancers (Basel) 2021; 13:cancers13040776. [PMID: 33668443 PMCID: PMC7917670 DOI: 10.3390/cancers13040776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 01/28/2023] Open
Abstract
Simple Summary Germ cell tumors (GCTs) are the most common solid malignancies in young men. GCTs are extraordinary sensitive to chemotherapy and represent a model of curable cancer. However, in a small proportion of patients the disease progresses or relapses despite administration of salvage chemotherapy. Apoptosis is a form of programmed cell death that occurs in multicellular organisms. It is well established that dysregulation of apoptosis plays an important role in pathogenesis of malignant diseases and may be associated with tumor progression and resistance to cytotoxic treatment. This study aimed to evaluate expression of apoptosis inducing factor (AIF) in GCTs. We observed lower AIF expression in GCTs compared to normal testicular tissue. We also showed prognostic significance of AIF in GCTs. AIF downregulation might represent one of the mechanisms of inhibition of apoptosis with subsequent facilitation of cell survival and metastatic dissemination of GCTs and perhaps could serve as a potential therapeutic target. Abstract Apoptosis is a strictly regulated process essential for preservation of tissue homeostasis. This study aimed to evaluate expression of apoptosis inducing factor (AIF) in testicular germ cell tumors (GCTs) and to correlate expression patterns with clinicopathological variables. Formalin-fixed and paraffin-embedded specimens of non-neoplastic testicular tissue and GCTs obtained from 216 patients were included in the study. AIF expression was detected by immunohistochemistry, scored by the multiplicative quickscore method (QS). Normal testicular tissue exhibits higher cytoplasmic granular expression of AIF compared to GCTs (mean QS = 12.77 vs. 4.80, p < 0.0001). Among invasive GCTs, mean QS was the highest in embryonal carcinoma, yolk sac tumor and seminoma, lower in teratoma and the lowest in choriocarcinoma. No nuclear translocation of AIF was observed. Nonpulmonary visceral metastases were associated with lower AIF expression. Metastatic GCTs patients with high AIF expression had better overall survival compared to patients with low AIF expression (HR = 0.26, 95% CI 0.11–0.62, p = 0.048). We observed significantly lower AIF expression in GCTs compared to normal testicular tissue, which is an uncommon finding in malignant tumors. AIF downregulation might represent one of the mechanisms of inhibition of apoptosis and promotion of cell survival in GCTs.
Collapse
Affiliation(s)
- Katarina Letkovska
- Department of Pathology, Faculty of Medicine, Comenius University, 813 72 Bratislava, Slovakia; (K.L.); (P.B.); (Z.C.); (S.H.); (P.J.)
| | - Pavel Babal
- Department of Pathology, Faculty of Medicine, Comenius University, 813 72 Bratislava, Slovakia; (K.L.); (P.B.); (Z.C.); (S.H.); (P.J.)
| | - Zuzana Cierna
- Department of Pathology, Faculty of Medicine, Comenius University, 813 72 Bratislava, Slovakia; (K.L.); (P.B.); (Z.C.); (S.H.); (P.J.)
- Department of Pathology, Faculty Hospital, A. Zarnova, 917 75 Trnava, Slovakia
| | - Silvia Schmidtova
- Translational Research Unit, 2nd Department of Oncology, Comenius University, Faculty of Medicine, National Cancer Institute, 833 10 Bratislava, Slovakia; (S.S.); (K.K.)
- Department of Molecular Oncology, Cancer Research Institute, Biomedical Research Center of the Slovak Academy of Sciences, 814 39 Bratislava, Slovakia
| | - Veronika Liskova
- Institute of Clinical and Translational Research, Biomedical Research Center of the Slovak Academy of Sciences, 845 05 Bratislava, Slovakia;
| | - Katarína Kalavska
- Translational Research Unit, 2nd Department of Oncology, Comenius University, Faculty of Medicine, National Cancer Institute, 833 10 Bratislava, Slovakia; (S.S.); (K.K.)
- Department of Molecular Oncology, Cancer Research Institute, Biomedical Research Center of the Slovak Academy of Sciences, 814 39 Bratislava, Slovakia
| | - Vera Miskovska
- 1st Department of Oncology, Comenius University, Faculty of Medicine, St. Elisabeth Cancer Institute, 812 50 Bratislava, Slovakia;
| | - Samuel Horak
- Department of Pathology, Faculty of Medicine, Comenius University, 813 72 Bratislava, Slovakia; (K.L.); (P.B.); (Z.C.); (S.H.); (P.J.)
| | - Katarina Rejlekova
- 2nd Department of Oncology, Comenius University, Faculty of Medicine, National Cancer Institute, 833 10 Bratislava, Slovakia; (K.R.); (M.C.); (J.M.)
| | - Michal Chovanec
- 2nd Department of Oncology, Comenius University, Faculty of Medicine, National Cancer Institute, 833 10 Bratislava, Slovakia; (K.R.); (M.C.); (J.M.)
| | - Jozef Mardiak
- 2nd Department of Oncology, Comenius University, Faculty of Medicine, National Cancer Institute, 833 10 Bratislava, Slovakia; (K.R.); (M.C.); (J.M.)
| | - Pavel Janega
- Department of Pathology, Faculty of Medicine, Comenius University, 813 72 Bratislava, Slovakia; (K.L.); (P.B.); (Z.C.); (S.H.); (P.J.)
| | - Michal Mego
- Translational Research Unit, 2nd Department of Oncology, Comenius University, Faculty of Medicine, National Cancer Institute, 833 10 Bratislava, Slovakia; (S.S.); (K.K.)
- 2nd Department of Oncology, Comenius University, Faculty of Medicine, National Cancer Institute, 833 10 Bratislava, Slovakia; (K.R.); (M.C.); (J.M.)
- Correspondence: ; Tel.: +421-2-59378366; Fax: +421-2-54774943
| |
Collapse
|
5
|
AIF meets the CHCHD4/Mia40-dependent mitochondrial import pathway. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165746. [PMID: 32105825 DOI: 10.1016/j.bbadis.2020.165746] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 02/06/2023]
Abstract
In the mitochondria of healthy cells, Apoptosis-Inducing factor (AIF) is required for the optimal functioning of the respiratory chain machinery, mitochondrial integrity, cell survival, and proliferation. In all analysed species, it was revealed that the downregulation or depletion of AIF provokes mainly the post-transcriptional loss of respiratory chain Complex I protein subunits. Recent progress in the field has revealed that AIF fulfils its mitochondrial pro-survival function by interacting physically and functionally with CHCHD4, the evolutionarily-conserved human homolog of yeast Mia40. The redox-regulated CHCHD4/Mia40-dependent import machinery operates in the intermembrane space of the mitochondrion and controls the import of a set of nuclear-encoded cysteine-motif carrying protein substrates. In addition to their participation in the biogenesis of specific respiratory chain protein subunits, CHCHD4/Mia40 substrates are also implicated in the control of redox regulation, antioxidant response, translation, lipid homeostasis and mitochondrial ultrastructure and dynamics. Here, we discuss recent insights on the AIF/CHCHD4-dependent protein import pathway and review current data concerning the CHCHD4/Mia40 protein substrates in metazoan. Recent findings and the identification of disease-associated mutations in AIF or in specific CHCHD4/Mia40 substrates have highlighted these proteins as potential therapeutic targets in a variety of human disorders.
Collapse
|
6
|
Khalsa JK, Chawla AS, Prabhu SB, Vats M, Dhar A, Dev G, Das N, Mukherjee S, Tanwar S, Banerjee H, Durdik JM, Bal V, George A, Rath S, Arimbasseri GA. Functionally significant metabolic differences between B and T lymphocyte lineages. Immunology 2019; 158:104-120. [PMID: 31318442 DOI: 10.1111/imm.13098] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/13/2019] [Accepted: 07/11/2019] [Indexed: 12/16/2022] Open
Abstract
Activation of B and T lymphocytes leads to major remodelling of the metabolic landscape of the cells enabling their post-activation functions. However, naive B and T lymphocytes also show metabolic differences, and the genesis, nature and functional significance of these differences are not yet well understood. Here we show that resting B-cells appeared to have lower energy demands than resting T-cells as they consumed lower levels of glucose and fatty acids and produced less ATP. Resting B-cells are more dependent on OXPHOS, while T-cells show more dependence on aerobic glycolysis. However, despite an apparently higher energy demand, T lineage cells showed lower rates of protein synthesis than equivalent B lineage stages. These metabolic differences between the two lineages were established early during lineage differentiation, and were functionally significant. Higher levels of protein synthesis in B-cells were associated with increased synthesis of MHC class II molecules and other proteins associated with antigen internalization, transport and presentation. The combination of higher energy demand and lower protein synthesis in T-cells was consistent with their higher ATP-dependent motility. Our data provide an integrated perspective of the metabolic differences and their functional implications between the B and T lymphocyte lineages.
Collapse
Affiliation(s)
| | | | - Savit B Prabhu
- Wellcome Laboratory, Christian Medical College, Vellore, India
| | - Mukti Vats
- National Institute of Immunology, New Delhi, India
| | - Atika Dhar
- National Institute of Immunology, New Delhi, India
| | - Gagan Dev
- National Institute of Immunology, New Delhi, India
| | - Nabanita Das
- Indian Institute of Chemical Biology, Kolkata, India
| | | | | | | | | | - Vineeta Bal
- National Institute of Immunology, New Delhi, India
| | - Anna George
- National Institute of Immunology, New Delhi, India
| | | | | |
Collapse
|
7
|
Scott AJ, Walker SA, Krank JJ, Wilkinson AS, Johnson KM, Lewis EM, Wilkinson JC. AIF promotes a JNK1-mediated cadherin switch independently of respiratory chain stabilization. J Biol Chem 2018; 293:14707-14722. [PMID: 30093403 DOI: 10.1074/jbc.ra118.004022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/26/2018] [Indexed: 12/18/2022] Open
Abstract
Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein occasionally involved in cell death that primarily regulates mitochondrial energy metabolism under normal cellular conditions. AIF catalyzes the oxidation of NADH in vitro, yet the significance of this redox activity in cells remains unclear. Here, we show that through its enzymatic activity AIF is a critical factor for oxidative stress-induced activation of the mitogen-activated protein kinases JNK1 (c-Jun N-terminal kinase), p38, and ERK (extracellular signal-regulated kinase). AIF-dependent JNK1 signaling culminates in the cadherin switch, and genetic reversal of this switch leads to apoptosis when AIF is suppressed. Notably, this widespread ability of AIF to promote JNK signaling can be uncoupled from its more limited role in respiratory chain stabilization. Thus, AIF is a transmitter of extra-mitochondrial signaling cues with important implications for human development and disease.
Collapse
Affiliation(s)
- Andrew J Scott
- From the Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108 and
| | - Sierra A Walker
- From the Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108 and
| | - Joshua J Krank
- From the Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108 and
| | - Amanda S Wilkinson
- From the Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108 and
| | - Kaitlyn M Johnson
- From the Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108 and
| | - Eric M Lewis
- the Department of Chemistry, Mathematics and Physics, Clarion University of Pennsylvania, Clarion, Pennsylvania 16214
| | - John C Wilkinson
- From the Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108 and
| |
Collapse
|
8
|
Chen ZR, Ma Y, Guo HH, Lu ZD, Jin QH. Therapeutic efficacy of cyclosporin A against spinal cord injury in rats with hyperglycemia. Mol Med Rep 2018; 17:4369-4375. [PMID: 29328412 PMCID: PMC5802210 DOI: 10.3892/mmr.2018.8422] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/24/2017] [Indexed: 01/20/2023] Open
Abstract
The present study aimed to explore the therapeutic effects of cyclosporin A (CsA) on spinal cord injury (SCI) in rats with hyperglycemia and to identify a novel potential method to treat SCI in the presence of hyperglycemia. Female Sprague‑Dawley (SD) rats were randomly allocated into four groups: Sham, SCI, SCI+hyperglycemia and SCI+hyperglycemia+CsA groups. Streptozotocin‑induced hyperglycemic SD rats and a weight‑drop contusion SCI model were established. The Basso, Beattie, Bresnahan scale and inclined plane test were used to evaluate the neurological function of the rats. Flow cytometric assay was performed to detect the apoptotic rates of cells in the spinal cord. ELISA and western blot analysis were performed to determine the levels of interleukin (IL)‑10, tumor necrosis factor (TNF)‑α, cyclophilin‑D (Cyp‑D) and apoptosis‑inducing factor (AIF). The results demonstrated that CsA significantly improved the neurological function of the SCI rats with hyperglycemia. CsA markedly reduced the number of apoptotic cells exaggerated by hyperglycemia in the spinal cord of the SCI rats. CsA significantly decreased the expression levels of IL‑10, TNF‑α, Cyp‑D and AIF in the spinal cord of the SCI rats. Overall, the present study revealed a significant role of CsA in the treatment of SCI in the presence of hyperglycemia by inhibiting the apoptosis of spinal cord cells.
Collapse
Affiliation(s)
- Zhi-Rong Chen
- Department of Orthopedics, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Yi Ma
- Department of Pathology and Physiology, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Hao-Hui Guo
- Department of Orthopedics, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Zhi-Dong Lu
- Department of Orthopedics, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Qun-Hua Jin
- Department of Orthopedics, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| |
Collapse
|
9
|
Lenhausen AM, Wilkinson AS, Lewis EM, Dailey KM, Scott AJ, Khan S, Wilkinson JC. Apoptosis Inducing Factor Binding Protein PGAM5 Triggers Mitophagic Cell Death That Is Inhibited by the Ubiquitin Ligase Activity of X-Linked Inhibitor of Apoptosis. Biochemistry 2016; 55:3285-302. [PMID: 27218139 DOI: 10.1021/acs.biochem.6b00306] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Apoptosis inducing factor (AIF) plays a well-defined role in controlling cell death but is also a critical factor for maintaining mitochondrial energy homeostasis; how these dueling activities are balanced has remained largely elusive. To identify new AIF binding partners that may define the continuum of AIF cellular regulation, a biochemical screen was performed that identified the mitochondrial phosphoglycerate mutase 5 (PGAM5) as an AIF associated factor. AIF binds both the short and long isoforms of PGAM5 and can reduce the ability of PGAM5 to control antioxidant responses. Transient overexpression of either PGAM5 isoform triggers caspase activation and cell death, and while AIF could reduce this caspase activation neither AIF expression nor caspase activity is required for PGAM5-mediated death. PGAM5 toxicity morphologically and biochemically resembles mitophagic cell death and is inhibited by the AIF binding protein X-linked inhibitor of apoptosis (XIAP) in a manner that depends on the ubiquitin ligase activity of XIAP. The phosphatase activity of PGAM5 was not required for cell death, and comparison of phosphatase activity between short and long PGAM5 isoforms suggested that only the long isoform is catalytically competent. This property correlated with an increased ability of PGAM5L to form dimers and/or higher order oligomers in intact cells compared to PGAM5S. Overall this study identifies an AIF/PGAM5/XIAP axis that can regulate PGAM5 activities related to the antioxidant response and mitophagy.
Collapse
Affiliation(s)
- Audrey M Lenhausen
- Department of Biochemistry, Wake Forest School of Medicine , Winston-Salem, North Carolina 27157, United States
| | - Amanda S Wilkinson
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108, United States
| | - Eric M Lewis
- Department of Biochemistry, Wake Forest School of Medicine , Winston-Salem, North Carolina 27157, United States
| | - Kaitlin M Dailey
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108, United States
| | - Andrew J Scott
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108, United States
| | - Shahzeb Khan
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108, United States
| | - John C Wilkinson
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108, United States
| |
Collapse
|