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Rejdak K, Sienkiewicz-Jarosz H, Bienkowski P, Alvarez A. Modulation of neurotrophic factors in the treatment of dementia, stroke and TBI: Effects of Cerebrolysin. Med Res Rev 2023; 43:1668-1700. [PMID: 37052231 DOI: 10.1002/med.21960] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/21/2023] [Accepted: 03/27/2023] [Indexed: 04/14/2023]
Abstract
Neurotrophic factors (NTFs) are involved in the pathophysiology of neurological disorders such as dementia, stroke and traumatic brain injury (TBI), and constitute molecular targets of high interest for the therapy of these pathologies. In this review we provide an overview of current knowledge of the definition, discovery and mode of action of five NTFs, nerve growth factor, insulin-like growth factor 1, brain derived NTF, vascular endothelial growth factor and tumor necrosis factor alpha; as well as on their contribution to brain pathology and potential therapeutic use in dementia, stroke and TBI. Within the concept of NTFs in the treatment of these pathologies, we also review the neuropeptide preparation Cerebrolysin, which has been shown to resemble the activities of NTFs and to modulate the expression level of endogenous NTFs. Cerebrolysin has demonstrated beneficial treatment capabilities in vitro and in clinical studies, which are discussed within the context of the biochemistry of NTFs. The review focuses on the interactions of different NTFs, rather than addressing a single NTF, by outlining their signaling network and by reviewing their effect on clinical outcome in prevalent brain pathologies. The effects of the interactions of these NTFs and Cerebrolysin on neuroplasticity, neurogenesis, angiogenesis and inflammation, and their relevance for the treatment of dementia, stroke and TBI are summarized.
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Affiliation(s)
- Konrad Rejdak
- Department of Neurology, Medical University of Lublin, Lublin, Poland
| | | | | | - Anton Alvarez
- Medinova Institute of Neurosciences, Clinica RehaSalud, Coruña, Spain
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2
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Li Z, Duan Y, Mao W, Chen C, Yuan W, Jin X, Shi S, Su XC, Ibáñez CF, Lin Z. Equilibrium between monomers and dimers of the death domain of the p75 neurotrophin receptor in solution. Int J Biol Macromol 2023; 246:125710. [PMID: 37414319 DOI: 10.1016/j.ijbiomac.2023.125710] [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: 03/12/2023] [Revised: 06/21/2023] [Accepted: 07/03/2023] [Indexed: 07/08/2023]
Abstract
p75 neurotrophin receptor (p75NTR) contains a C-terminal globular protein module known as the death domain (DD), which plays a central role in apoptotic and inflammatory signaling through the formation of oligomeric protein complexes. A monomeric state of the p75NTR-DD also exists depending on its chemical environment in vitro. However, studies on the oligomeric states of the p75NTR-DD have produced conflicting findings and sparked great controversy. Here we present new evidence from biophysical and biochemical studies to demonstrate the coexistence of symmetric and asymmetric dimers of the p75NTR-DD, which may equilibrate with the monomeric form in solution and in the absence of any other protein. The reversible close-open solution behavior may be important for the p75NTR-DD to serve as an intracellular signaling hub. This result supports an intrinsic ability of the p75NTR-DD to self-associate, in congruence with the oligomerization properties of all members of the DD superfamily.
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Affiliation(s)
- Zhen Li
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Yajing Duan
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Wenhui Mao
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Cheng Chen
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Wensu Yuan
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin 300072, China
| | - Xinghua Jin
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China
| | - Shuo Shi
- State Key Laboratory of Elemento-Organic Chemistry and College of Chemistry, Nankai University, Tianjin 300071, China
| | - Xun-Cheng Su
- State Key Laboratory of Elemento-Organic Chemistry and College of Chemistry, Nankai University, Tianjin 300071, China
| | - Carlos F Ibáñez
- Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University School of Life Sciences and Chinese Institute for Brain Research, Beijing 100871, China; Department of Neuroscience, Karolinska Institute, Stockholm 17177, Sweden.
| | - Zhi Lin
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin 300072, China.
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Xiong LL, Chen L, Deng IB, Zhou XF, Wang TH. P75 neurotrophin receptor as a therapeutic target for drug development to treat neurological diseases. Eur J Neurosci 2022; 56:5299-5318. [PMID: 36017737 DOI: 10.1111/ejn.15810] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/11/2022] [Accepted: 08/23/2022] [Indexed: 12/14/2022]
Abstract
The interaction of neurotrophins with their receptors is involved in the pathogenesis and progression of various neurological diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, spinal cord injury and acute and chronic cerebral damage. The p75 neurotrophin receptor (p75NTR) plays a pivotal role in the development of neurological dysfunctions as a result of its high expression, abnormal processing and signalling. Therefore, p75NTR represents as a vital therapeutic target for the treatment of neurodegeneration, neuropsychiatric disorders and cerebrovascular insufficiency. This review summarizes the current research progress on the p75NTR signalling in neurological deficits. We also summarize the present therapeutic approaches by genetically and pharmacologically targeting p75NTR for the attenuation of pathological changes. Based on the evolving knowledge, the role of p75NTR in the regulation of tau hyperphosphorylation, Aβ metabolism, the degeneration of motor neurons and dopaminergic neurons has been discussed. Its position as a biomarker to evaluate the severity of diseases and as a druggable target for drug development has also been elucidated. Several prototype small molecule compounds were introduced to be crucial in neuronal survival and functional recovery via targeting p75NTR. These small molecule compounds represent desirable agents in attenuating neurodegeneration and cell death as they abolish activation-induced neurotoxicity of neurotrophins via modulating p75NTR signalling. More comprehensive and in-depth investigations on p75NTR-based drug development are required to shed light on effective treatment of numerous neurological disorders.
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Affiliation(s)
- Liu-Lin Xiong
- Institute of Neurological Disease, West China Hospital, Sichuan University, Chengdu, China.,Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia.,Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Li Chen
- Institute of Neurological Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Isaac Bul Deng
- Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Xin-Fu Zhou
- Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Ting-Hua Wang
- Institute of Neurological Disease, West China Hospital, Sichuan University, Chengdu, China
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Wang P, Chang Z, Meng J, Cui X, Chai J, Dang T. RETRACTED ARTICLE: Overexpression of CCN1 in esophageal squamous cell carcinoma attenuates cell proliferation through amyloid precursor protein without DR6 involvement. Hum Cell 2022; 35:1630. [PMID: 35639282 DOI: 10.1007/s13577-022-00726-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/16/2022] [Indexed: 02/02/2023]
Affiliation(s)
- Pei Wang
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou, 014030, Inner Mongolia, China
| | - Zhiheng Chang
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou, 014030, Inner Mongolia, China
| | - Jing Meng
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou, 014030, Inner Mongolia, China
| | - Xia Cui
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou, 014030, Inner Mongolia, China
| | - Jianyuan Chai
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou, 014030, Inner Mongolia, China.
- College of Medicine, University of California, Irvine, CA, 92697, USA.
| | - Tong Dang
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou, 014030, Inner Mongolia, China.
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Electroacupuncture promotes apoptosis and inhibits axonogenesis by activating p75 neurotrophin receptor for triple-negative breast xenograft in mice. J Chem Neuroanat 2022; 124:102133. [PMID: 35777527 DOI: 10.1016/j.jchemneu.2022.102133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 06/26/2022] [Accepted: 06/26/2022] [Indexed: 10/17/2022]
Abstract
PURPOSE The aim of this study was to investigate the anti-tumor effect of electroacupuncture (EA) on mice bearing breast tumors by regulating p75 neurotrophin receptor (p75NTR) and remodelling intratumoral innervation. METHODS Female BALB/c mice were implanted with 4T1 breast tumor cells to establish a murine mammary cancer model. Tumor volume and weight were measured to evaluate tumor growth. Cell apoptosis was assessed by TUNEL assay. The relative expression of p75NTR, TrkA, TrkB, NGF and proNGF were detected by immunohistochemistry. Neurotransmitter and neurotrophin were detected by enzyme-linked immunosorbent assay. Intratumoral innervation was confirmed by β3-tubulin and TH labeling immunohistochemistry. The antagonist TAT-Pep5 was employed to determine if the effects of EA on tumor growth and cell apoptosis were mediated by p75NTR. RESULTS Peritumoral EA alleviated tumor growth especially after 14 days of intervention. Apoptosis index in the tumor tissue was obviously decreased after EA. Meanwhile, EA intervention significantly upregulated the expression of p75NTR and proNGF, along with a decline in the tumor growth and an increase in the cell apoptosis. Besides, EA reduced local sympathetic innervation and downregulated sympathetic neurotransmitter NE level in the local tumor. Furthermore, p75NTR antagonist alleviated EA-mediated cell apoptosis and intratumoral innervation. CONCLUSIONS One mechanism of EA intervention for alleviating tumor progression is mediated by p75NTR to promote apoptosis and decrease intratumoral axonogenesis in the tumor microenvironment.
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Wang P, Chang Z, Meng J, Cui X, Chai J, Dang T. CCN1 suppresses cell proliferation of esophageal squamous cell carcinoma through amyloid precursor protein without DR6 participation. Cell Signal 2022; 96:110374. [PMID: 35654297 DOI: 10.1016/j.cellsig.2022.110374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 01/21/2023]
Abstract
Esophageal cancer is commonly seen as either squamous cell carcinoma (ESCC) or adenocarcinoma (EAC), two very different cancers. CCN1 is a matricellular protein that induces apoptosis in EAC cells through upregulation of DR5, a death receptor, while its role in ESCC is unclear. DR6 is another death receptor, which has been reported to induce apoptosis, necroptosis, or pyroptosis in various cell systems with or without the engagement of its putative ligand amyloid precursor protein (APP). In this study, we found that CCN1 and DR6 were both highly expressed in ESCC but downregulated in EAC. Overexpression of CCN1 in ESCC cells inhibited cell proliferation through upregulation of APP and its association with p53 without DR6 involvement. Overexpression of APP stopped cell growth, but overexpression of DR6 did not affect cell growth or cell death whatsoever.
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Affiliation(s)
- Pei Wang
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou 014030, China
| | - Zhiheng Chang
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou 014030, China
| | - Jing Meng
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou 014030, China
| | - Xia Cui
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou 014030, China
| | - Jianyuan Chai
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou 014030, China.
| | - Tong Dang
- Inner Mongolia Institute of Digestive Diseases, Inner Mongolia Engineering Research Center for Prevention and Treatment of Digestive Diseases, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, 30 Hudemulin Rd, Baotou 014030, China.
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Qin X, Wang J, Chen S, Liu G, Wu C, Lv Q, He X, Bai X, Huang W, Liao H. Astrocytic p75 NTR expression provoked by ischemic stroke exacerbates the blood-brain barrier disruption. Glia 2022; 70:892-912. [PMID: 35064700 DOI: 10.1002/glia.24146] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 01/07/2022] [Accepted: 01/09/2022] [Indexed: 12/16/2022]
Abstract
The disruption of the blood-brain barrier (BBB) plays a critical role in the pathology of ischemic stroke. p75 neurotrophin receptor (p75NTR ) contributes to the disruption of the blood-retinal barrier in retinal ischemia. However, whether p75NTR influences the BBB permeability after acute cerebral ischemia remains unknown. The present study investigated the role and underlying mechanism of p75NTR on BBB integrity in an ischemic stroke mouse model, middle cerebral artery occlusion (MCAO). After 24 h of MCAO, astrocytes and endothelial cells in the infarct-affected brain area up-regulated p75NTR . Genetic p75NTR knockdown (p75NTR+/- ) or pharmacological inhibition of p75NTR using LM11A-31, a selective inhibitor of p75NTR , both attenuated brain damage and BBB leakage in MCAO mice. Astrocyte-specific conditional knockdown of p75NTR mediated with an adeno-associated virus significantly ameliorated BBB disruption and brain tissue damage, as well as the neurological functions after stroke. Further molecular biological examinations indicated that astrocytic p75NTR activated NF-κB and HIF-1α signals, which upregulated the expression of MMP-9 and vascular endothelial growth factor (VEGF), subsequently leading to tight junction degradation after ischemia. As a result, increased leukocyte infiltration and microglia activation exacerbated brain injury after stroke. Overall, our results provide novel insight into the role of astrocytic p75NTR in BBB disruption after acute cerebral ischemia. The p75NTR may therefore be a potential therapeutic target for the treatment of ischemic stroke.
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Affiliation(s)
- Xiaoying Qin
- New drug screening center, Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing, China
| | - Jianing Wang
- New drug screening center, Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing, China
| | - Shujian Chen
- New drug screening center, Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing, China
| | - Gang Liu
- New drug screening center, Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing, China
| | - Chaoran Wu
- New drug screening center, Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing, China
| | - Qunyu Lv
- New drug screening center, Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing, China
| | - Xinran He
- New drug screening center, Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing, China
| | - Xianshu Bai
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Wenhui Huang
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Hong Liao
- New drug screening center, Jiangsu Center for Pharmacodynamics Research and Evaluation, China Pharmaceutical University, Nanjing, China
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Ren X, Lin Z, Yuan W. A Structural and Functional Perspective of Death Receptor 6. Front Pharmacol 2022; 13:836614. [PMID: 35401228 PMCID: PMC8987162 DOI: 10.3389/fphar.2022.836614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/23/2022] [Indexed: 11/13/2022] Open
Abstract
As a member of the tumor necrosis factor receptor superfamily (TNFRSF), death receptor 6 (DR6) has a similar structural architecture to other family members. The extracellular region of DR6 contains four cysteine-rich domains, followed by a single-pass transmembrane domain and an intracellular region. Since its discovery, DR6 has become an orphan receptor ubiquitously expressed to transduce unique signaling pathways. Although the free ectodomains of β-amyloid precursor protein (APP) can bind to DR6 to induce apoptotic signals, the natural ligands of DR6 still remain largely unknown. In this review, we focus on recent research progress of structural and functional studies on DR6 for better understanding DR6-mediated signaling and the treatment of DR6-related diseases.
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Affiliation(s)
| | - Zhi Lin
- *Correspondence: Wensu Yuan, ; Zhi Lin,
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Eggert S, Kins S, Endres K, Brigadski T. Brothers in arms: proBDNF/BDNF and sAPPα/Aβ-signaling and their common interplay with ADAM10, TrkB, p75NTR, sortilin, and sorLA in the progression of Alzheimer's disease. Biol Chem 2022; 403:43-71. [PMID: 34619027 DOI: 10.1515/hsz-2021-0330] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/16/2021] [Indexed: 12/22/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is an important modulator for a variety of functions in the central nervous system (CNS). A wealth of evidence, such as reduced mRNA and protein level in the brain, cerebrospinal fluid (CSF), and blood samples of Alzheimer's disease (AD) patients implicates a crucial role of BDNF in the progression of this disease. Especially, processing and subcellular localization of BDNF and its receptors TrkB and p75 are critical determinants for survival and death in neuronal cells. Similarly, the amyloid precursor protein (APP), a key player in Alzheimer's disease, and its cleavage fragments sAPPα and Aβ are known for their respective roles in neuroprotection and neuronal death. Common features of APP- and BDNF-signaling indicate a causal relationship in their mode of action. However, the interconnections of APP- and BDNF-signaling are not well understood. Therefore, we here discuss dimerization properties, localization, processing by α- and γ-secretase, relevance of the common interaction partners TrkB, p75, sorLA, and sortilin as well as shared signaling pathways of BDNF and sAPPα.
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Affiliation(s)
- Simone Eggert
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, D-67663 Kaiserslautern, Germany
| | - Stefan Kins
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, D-67663 Kaiserslautern, Germany
| | - Kristina Endres
- Department of Psychiatry and Psychotherapy, University Medical Center, Johannes Gutenberg-University Mainz, D-55131 Mainz, Germany
| | - Tanja Brigadski
- Department of Informatics and Microsystem Technology, University of Applied Sciences Kaiserslautern, D-66482 Zweibrücken, Germany
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Mansour MA, Caputo VS, Aleem E. Highlights on selected growth factors and their receptors as promising anticancer drug targets. Int J Biochem Cell Biol 2021; 140:106087. [PMID: 34563698 DOI: 10.1016/j.biocel.2021.106087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 09/16/2021] [Accepted: 09/20/2021] [Indexed: 10/20/2022]
Abstract
Growth factor receptors (GFRs) and receptor tyrosine kinases (RTK) are groups of proteins mediating a plethora of physiological processes, including cell growth, proliferation, survival, differentiation and migration. Under certain circumstances, expression of GFRs and subsequently their downstream kinase signaling are deregulated by genetic, epigenetic, and somatic changes leading to uncontrolled cell division in many human diseases, most notably cancer. Cancer cells rely on growth factors to sustain the increasing need to cell division and metabolic reprogramming through cancer-associated activating mutations of their receptors (i.e., GFRs). In this review, we highlight the recent advances of selected GFRs and their ligands (growth factors) in cancer with emphasis on structural and functional differences. We also interrogate how overexpression and/or hyperactivation of GFRs contribute to cancer initiation, development, progression, and resistance to conventional chemo- and radiotherapies. Novel approaches are being developed as anticancer agents to target growth factor receptors and their signaling pathways in different cancers. Here, we illustrate how the current knowledge of GFRs biology, and their ligands lead to development of targeted therapies to inhibit and/or block the activity of growth factors, GFRs and downstream kinases to treat diseases such as cancer.
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Affiliation(s)
- Mohammed A Mansour
- Cancer Biology and Therapy Lab, Division of Human Sciences, School of Applied Sciences, London South Bank University, London, UK; Biochemistry Division, Department of Chemistry, Faculty of Science, Tanta University, Tanta 31527, Egypt.
| | - Valentina S Caputo
- Cancer Biology and Therapy Lab, Division of Human Sciences, School of Applied Sciences, London South Bank University, London, UK
| | - Eiman Aleem
- Cancer Biology and Therapy Lab, Division of Human Sciences, School of Applied Sciences, London South Bank University, London, UK.
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Zhang N, Kisiswa L, Ramanujan A, Li Z, Sim EW, Tian X, Yuan W, Ibáñez CF, Lin Z. Structural basis of NF-κB signaling by the p75 neurotrophin receptor interaction with adaptor protein TRADD through their respective death domains. J Biol Chem 2021; 297:100916. [PMID: 34175311 PMCID: PMC8318917 DOI: 10.1016/j.jbc.2021.100916] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 11/17/2022] Open
Abstract
The p75 neurotrophin receptor (p75NTR) is a critical mediator of neuronal death and tissue remodeling and has been implicated in various neurodegenerative diseases and cancers. The death domain (DD) of p75NTR is an intracellular signaling hub and has been shown to interact with diverse adaptor proteins. In breast cancer cells, binding of the adaptor protein TRADD to p75NTR depends on nerve growth factor and promotes cell survival. However, the structural mechanism and functional significance of TRADD recruitment in neuronal p75NTR signaling remain poorly understood. Here we report an NMR structure of the p75NTR-DD and TRADD-DD complex and reveal the mechanism of specific recognition of the TRADD-DD by the p75NTR-DD mainly through electrostatic interactions. Furthermore, we identified spatiotemporal overlap of p75NTR and TRADD expression in developing cerebellar granule neurons (CGNs) at early postnatal stages and discover the physiological relevance of the interaction between TRADD and p75NTR in the regulation of canonical NF-κB signaling and cell survival in CGNs. Our results provide a new structural framework for understanding how the recruitment of TRADD to p75NTR through DD interactions creates a membrane-proximal platform, which can be efficiently regulated by various neurotrophic factors through extracellular domains of p75NTR, to propagate downstream signaling in developing neurons.
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Affiliation(s)
- Ning Zhang
- School of Life Sciences, Tianjin University, Tianjin, PR China; Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin, PR China
| | - Lilian Kisiswa
- Department of Physiology, National University of Singapore, Singapore; Life Sciences Institute, National University of Singapore, Singapore; Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Ajeena Ramanujan
- Department of Physiology, National University of Singapore, Singapore; Life Sciences Institute, National University of Singapore, Singapore
| | - Zhen Li
- School of Life Sciences, Tianjin University, Tianjin, PR China; Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin, PR China
| | - Eunice Weiling Sim
- Department of Physiology, National University of Singapore, Singapore; Life Sciences Institute, National University of Singapore, Singapore
| | - Xianbin Tian
- School of Life Sciences, Tianjin University, Tianjin, PR China; Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin, PR China
| | - Wensu Yuan
- School of Life Sciences, Tianjin University, Tianjin, PR China; Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin, PR China
| | - Carlos F Ibáñez
- Department of Physiology, National University of Singapore, Singapore; Life Sciences Institute, National University of Singapore, Singapore; Department of Neuroscience, Karolinska Institute, Stockholm, Sweden; Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University School of Life Sciences and Chinese Institute for Brain Research, Beijing, China
| | - Zhi Lin
- School of Life Sciences, Tianjin University, Tianjin, PR China; Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin, PR China; Department of Physiology, National University of Singapore, Singapore; Life Sciences Institute, National University of Singapore, Singapore.
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12
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Colardo M, Martella N, Pensabene D, Siteni S, Di Bartolomeo S, Pallottini V, Segatto M. Neurotrophins as Key Regulators of Cell Metabolism: Implications for Cholesterol Homeostasis. Int J Mol Sci 2021; 22:5692. [PMID: 34073639 PMCID: PMC8198482 DOI: 10.3390/ijms22115692] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/14/2022] Open
Abstract
Neurotrophins constitute a family of growth factors initially characterized as predominant mediators of nervous system development, neuronal survival, regeneration and plasticity. Their biological activity is promoted by the binding of two different types of receptors, leading to the generation of multiple and variegated signaling cascades in the target cells. Increasing evidence indicates that neurotrophins are also emerging as crucial regulators of metabolic processes in both neuronal and non-neuronal cells. In this context, it has been reported that neurotrophins affect redox balance, autophagy, glucose homeostasis and energy expenditure. Additionally, the trophic support provided by these secreted factors may involve the regulation of cholesterol metabolism. In this review, we examine the neurotrophins' signaling pathways and their effects on metabolism by critically discussing the most up-to-date information. In particular, we gather experimental evidence demonstrating the impact of these growth factors on cholesterol metabolism.
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Affiliation(s)
- Mayra Colardo
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy; (M.C.); (N.M.); (D.P.); (S.D.B.)
| | - Noemi Martella
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy; (M.C.); (N.M.); (D.P.); (S.D.B.)
| | - Daniele Pensabene
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy; (M.C.); (N.M.); (D.P.); (S.D.B.)
| | - Silvia Siteni
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA;
| | - Sabrina Di Bartolomeo
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy; (M.C.); (N.M.); (D.P.); (S.D.B.)
| | - Valentina Pallottini
- Department of Science, University Roma Tre, Viale Marconi 446, 00146 Rome, Italy;
- Neuroendocrinology Metabolism and Neuropharmacology Unit, IRCSS Fondazione Santa Lucia, Via del Fosso Fiorano 64, 00143 Rome, Italy
| | - Marco Segatto
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy; (M.C.); (N.M.); (D.P.); (S.D.B.)
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Tang JJ, Feng S, Chen XD, Huang H, Mao M, Wang HY, Li S, Lu XM, Wang YT. The Effects of P75NTR on Learning Memory Mediated by Hippocampal Apoptosis and Synaptic Plasticity. Curr Pharm Des 2021; 27:531-539. [PMID: 32938344 DOI: 10.2174/1381612826666200916145142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 08/18/2020] [Indexed: 11/22/2022]
Abstract
Neurological diseases bring great mental and physical torture to the patients, and have long-term and sustained negative effects on families and society. The attention to neurological diseases is increasing, and the improvement of the material level is accompanied by an increase in the demand for mental level. The p75 neurotrophin receptor (p75NTR) is a low-affinity neurotrophin receptor and involved in diverse and pleiotropic effects in the developmental and adult central nervous system (CNS). Since neurological diseases are usually accompanied by the regression of memory, the pathogenesis of p75NTR also activates and inhibits other signaling pathways, which has a serious impact on the learning and memory of patients. The results of studies shown that p75NTR is associated with LTP/LTD-induced synaptic enhancement and inhibition, suggest that p75NTR may be involved in the progression of synaptic plasticity. And its proapoptotic effect is associated with activation of proBDNF and inhibition of proNGF, and TrkA/p75NTR imbalance leads to pro-survival or proapoptotic phenomena. It can be inferred that p75NTR mediates apoptosis in the hippocampus and amygdale, which may affect learning and memory behavior. This article mainly discusses the relationship between p75NTR and learning memory and associated mechanisms, which may provide some new ideas for the treatment of neurological diseases.
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Affiliation(s)
- Jun-Jie Tang
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China
| | - Shuang Feng
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China
| | - Xing-Dong Chen
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China
| | - Hua Huang
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China
| | - Min Mao
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China
| | - Hai-Yan Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Sen Li
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Xiu-Min Lu
- College of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China
| | - Yong-Tang Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing 400042, China
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14
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Zha K, Yang Y, Tian G, Sun Z, Yang Z, Li X, Sui X, Liu S, Zhao J, Guo Q. Nerve growth factor (NGF) and NGF receptors in mesenchymal stem/stromal cells: Impact on potential therapies. Stem Cells Transl Med 2021; 10:1008-1020. [PMID: 33586908 PMCID: PMC8235142 DOI: 10.1002/sctm.20-0290] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 12/27/2020] [Accepted: 01/12/2021] [Indexed: 12/13/2022] Open
Abstract
Mesenchymal stem/stromal cells (MSCs) are promising for the treatment of degenerative diseases and traumatic injuries. However, MSC engraftment is not always successful and requires a strong comprehension of the cytokines and their receptors that mediate the biological behaviors of MSCs. The effects of nerve growth factor (NGF) and its two receptors, TrkA and p75NTR, on neural cells are well studied. Increasing evidence shows that NGF, TrkA, and p75NTR are also involved in various aspects of MSC function, including their survival, growth, differentiation, and angiogenesis. The regulatory effect of NGF on MSCs is thought to be achieved mainly through its binding to TrkA. p75NTR, another receptor of NGF, is regarded as a novel surface marker of MSCs. This review provides an overview of advances in understanding the roles of NGF and its receptors in MSCs as well as the effects of MSC‐derived NGF on other cell types, which will provide new insight for the optimization of MSC‐based therapy.
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Affiliation(s)
- Kangkang Zha
- Medical School of Chinese PLA, Beijing, People's Republic of China.,Institute of Orthopaedics, Chinese PLA General Hospital, Beijing Key Lab of Regenerative Medicine in Orthopaedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Beijing, People's Republic of China.,School of Medicine, Nankai University, Tianjin, People's Republic of China
| | - Yu Yang
- Department of Othopaedics, Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, People's Republic of China
| | - Guangzhao Tian
- Medical School of Chinese PLA, Beijing, People's Republic of China.,Institute of Orthopaedics, Chinese PLA General Hospital, Beijing Key Lab of Regenerative Medicine in Orthopaedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Beijing, People's Republic of China.,School of Medicine, Nankai University, Tianjin, People's Republic of China
| | - Zhiqiang Sun
- Medical School of Chinese PLA, Beijing, People's Republic of China.,Institute of Orthopaedics, Chinese PLA General Hospital, Beijing Key Lab of Regenerative Medicine in Orthopaedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Beijing, People's Republic of China.,School of Medicine, Nankai University, Tianjin, People's Republic of China
| | - Zhen Yang
- Medical School of Chinese PLA, Beijing, People's Republic of China.,Institute of Orthopaedics, Chinese PLA General Hospital, Beijing Key Lab of Regenerative Medicine in Orthopaedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Beijing, People's Republic of China.,School of Medicine, Nankai University, Tianjin, People's Republic of China
| | - Xu Li
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Innovative Orthopaedic Biomaterial and Drug Translational Research Laboratory, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Xiang Sui
- Institute of Orthopaedics, Chinese PLA General Hospital, Beijing Key Lab of Regenerative Medicine in Orthopaedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Beijing, People's Republic of China
| | - Shuyun Liu
- Institute of Orthopaedics, Chinese PLA General Hospital, Beijing Key Lab of Regenerative Medicine in Orthopaedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Beijing, People's Republic of China
| | - Jinmin Zhao
- Department of Othopaedics, Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, People's Republic of China
| | - Quanyi Guo
- Institute of Orthopaedics, Chinese PLA General Hospital, Beijing Key Lab of Regenerative Medicine in Orthopaedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Beijing, People's Republic of China
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Ozalp O, Cark O, Azbazdar Y, Haykir B, Cucun G, Kucukaylak I, Alkan-Yesilyurt G, Sezgin E, Ozhan G. Nradd Acts as a Negative Feedback Regulator of Wnt/β-Catenin Signaling and Promotes Apoptosis. Biomolecules 2021; 11:100. [PMID: 33466728 PMCID: PMC7828832 DOI: 10.3390/biom11010100] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 12/16/2022] Open
Abstract
Wnt/β-catenin signaling controls many biological processes for the generation and sustainability of proper tissue size, organization and function during development and homeostasis. Consequently, mutations in the Wnt pathway components and modulators cause diseases, including genetic disorders and cancers. Targeted treatment of pathway-associated diseases entails detailed understanding of the regulatory mechanisms that fine-tune Wnt signaling. Here, we identify the neurotrophin receptor-associated death domain (Nradd), a homolog of p75 neurotrophin receptor (p75NTR), as a negative regulator of Wnt/β-catenin signaling in zebrafish embryos and in mammalian cells. Nradd significantly suppresses Wnt8-mediated patterning of the mesoderm and neuroectoderm during zebrafish gastrulation. Nradd is localized at the plasma membrane, physically interacts with the Wnt receptor complex and enhances apoptosis in cooperation with Wnt/β-catenin signaling. Our functional analyses indicate that the N-glycosylated N-terminus and the death domain-containing C-terminus regions are necessary for both the inhibition of Wnt signaling and apoptosis. Finally, Nradd can induce apoptosis in mammalian cells. Thus, Nradd regulates cell death as a modifier of Wnt/β-catenin signaling during development.
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Affiliation(s)
- Ozgun Ozalp
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, 35340 Izmir, Turkey; (O.O.); (O.C.); (Y.A.); (B.H.); (G.C.); (I.K.); (G.A.-Y.)
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Inciralti-Balcova, 35340 Izmir, Turkey
| | - Ozge Cark
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, 35340 Izmir, Turkey; (O.O.); (O.C.); (Y.A.); (B.H.); (G.C.); (I.K.); (G.A.-Y.)
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Inciralti-Balcova, 35340 Izmir, Turkey
| | - Yagmur Azbazdar
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, 35340 Izmir, Turkey; (O.O.); (O.C.); (Y.A.); (B.H.); (G.C.); (I.K.); (G.A.-Y.)
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Inciralti-Balcova, 35340 Izmir, Turkey
| | - Betul Haykir
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, 35340 Izmir, Turkey; (O.O.); (O.C.); (Y.A.); (B.H.); (G.C.); (I.K.); (G.A.-Y.)
- Institute of Physiology, Switzerland and National Center of Competence in Research NCCR Kidney, University of Zurich, CH-8057 Zurich, Switzerland
| | - Gokhan Cucun
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, 35340 Izmir, Turkey; (O.O.); (O.C.); (Y.A.); (B.H.); (G.C.); (I.K.); (G.A.-Y.)
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Inciralti-Balcova, 35340 Izmir, Turkey
| | - Ismail Kucukaylak
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, 35340 Izmir, Turkey; (O.O.); (O.C.); (Y.A.); (B.H.); (G.C.); (I.K.); (G.A.-Y.)
- Institute of Zoology-Developmental Biology, University of Cologne, 50674 Cologne, Germany
| | - Gozde Alkan-Yesilyurt
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, 35340 Izmir, Turkey; (O.O.); (O.C.); (Y.A.); (B.H.); (G.C.); (I.K.); (G.A.-Y.)
| | - Erdinc Sezgin
- Science for Life Laboratory, Department of Women’s and Children’s Health, Karolinska Institutet, 17177 Stockholm, Sweden;
- MRC Weatherall Institute of Molecular Medicine, MRC Human Immunology Unit, University of Oxford, Oxford OX39DS, UK
| | - Gunes Ozhan
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, 35340 Izmir, Turkey; (O.O.); (O.C.); (Y.A.); (B.H.); (G.C.); (I.K.); (G.A.-Y.)
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Inciralti-Balcova, 35340 Izmir, Turkey
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16
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Nerve Growth Factor: The First Molecule of the Neurotrophin Family. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1331:3-10. [PMID: 34453288 DOI: 10.1007/978-3-030-74046-7_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neurotrophins (NTs) are molecules regulating differentiation, maintenance, and functional plasticity of vertebrate nervous systems. Nerve growth factor (NGF) was the first to be identified in the neurotrophin family. The long scientific history of NTs provided not only advancement in the neuroscience field but opened new scenarios involving different body districts in physiological and pathological conditions, which include the immune, endocrine, and skeletal system, vascular districts, inflammation, etc. To date, many biological aspects of NTs have been clarified, but the new discoveries are still opening new insights on molecular and cellular mechanisms and systemic effects, also affecting the possible therapeutic application of NTs. This short review summarizes the main aspects of NGF biology and biochemistry, including the role of the NGF precursor molecule, high- and low-affinity receptors and related intracellular pathways, and target cells.
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17
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Bottasso E. Toward the Existence of a Sympathetic Neuroplasticity Adaptive Mechanism Influencing the Immune Response. A Hypothetical View-Part I. Front Endocrinol (Lausanne) 2019; 10:632. [PMID: 31616373 PMCID: PMC6763740 DOI: 10.3389/fendo.2019.00632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 08/30/2019] [Indexed: 12/21/2022] Open
Abstract
The nervous system exerts a profound influence on the function of the immune system (IS), mainly through the sympathetic arm of the autonomic nervous system. In fact, the sympathetic nervous system richly innervates secondary lymphoid organs (SLOs) such as the spleen and lymph nodes. For decades, different research groups working in the field have consistently reported changes in the sympathetic innervation of the SLOs during the activation of the IS, which are characterized by a decreased noradrenergic activity and retraction of these fibers. Most of these groups interpreted these changes as a pathological phenomenon, referred to as "damage" or "injury" of the noradrenergic fibers. Some of them postulated that this "injury" was probably due to toxic effects of released endogenous mediators. Others, working on animal models of chronic stimulation of the IS, linked it to the very chronic nature of processes. Unlike these views, this first part of the present work reviews evidence which supports the hypothesis of a specific adaptive mechanism of neural plasticity from sympathetic fibers innervating SLOs, encompassing structural and functional changes of noradrenergic nerves. This plasticity mechanism would involve segmental retraction and degeneration of these fibers during the activation of the IS with subsequent regeneration once the steady state is recovered. The candidate molecules likely to mediate this phenomenon are also here introduced. The second part will extend this view as to the potential changes in sympathetic innervation likely to occur in inflamed non-lymphoid peripheral tissues and its possible immunological implications.
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