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Cranial irradiation induces cognitive decline associated with altered dendritic spine morphology in the young rat hippocampus. Childs Nerv Syst 2022; 38:1867-1875. [PMID: 35962792 DOI: 10.1007/s00381-022-05646-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 08/05/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVE Therapeutic irradiation is commonly used to treat brain cancers but can induce cognitive dysfunction, especially in children. The mechanism is unknown but likely involves alterations in dendritic spine number and structure. METHODS To explore the impact of radiation exposure on the alteration of dendritic spine morphology in the hippocampus of young brains, 21-day-old Sprague-Dawley rats received cranial irradiation (10 Gy), and changes in spine density and morphology in dentate gyrus (DG) granules and CA1 pyramidal neurons were detected 1 and 3 months later by using Golgi staining. Moreover, we analyzed synapse-associated proteins within dendritic spines after irradiation. RESULT Our data showed that cognitive deficits were detected in young rats at both time points postirradiation, accompanied by morphological changes in dendritic spines. Our results revealed significant reductions in spine density in the DG at both 1 month (40.58%) and 3 months (28.92%) postirradiation. However, there was a decrease in spine density only at 1 month (33.29%) postirradiation in the basal dendrites of CA1 neurons and no significant changes in the apical dendrites of CA1 neurons at either time point. Notably, among our findings were the significant dynamic changes in spine morphology that persisted 3 months following cranial irradiation. Meanwhile, we found that depletion of the synapse-associated proteins PSD95 and Drebrin coincided with alterations in dendritic spines. CONCLUSION These data suggest that the decreased levels of PSD95 and Drebrin after ionizing radiation may cause changes in synaptic plasticity by affecting the morphological structure of dendritic spines, blocking the functional connectivity pathways of the brain and leading to cognitive impairment. Although the mechanism involved is unclear, understanding how ionizing radiation affects young brain hippocampal tissue may be useful to gain new mechanistic insights into radiation-induced cognitive dysfunction.
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Zhang J, Zhang Y, Xu M, Miao Z, Tian Y. Inhibition of the CDK5/caspase-3 Pathway by p5-TAT Protects Hippocampal Neurogenesis and Alleviates Radiation-induced Cognitive Dysfunction. Neuroscience 2021; 463:204-215. [PMID: 33838288 DOI: 10.1016/j.neuroscience.2021.03.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/24/2021] [Accepted: 03/26/2021] [Indexed: 11/17/2022]
Abstract
Radiation-induced cognitive dysfunction is a common complication associated with cranial radiation therapy. Inhibition of hippocampal neurogenesis and proliferation plays a critical role in this complication. Relieving hippocampal apoptosis may significantly protect hippocampal neurogenesis and proliferation. Previous studies have demonstrated that hyperactivity of cyclin-dependent kinase 5 (Cdk5) is closely related to apoptosis. The exact molecular changes and function of Cdk5 in radiation-induced cognitive dysfunction are still not clear. Whether inhibition of Cdk5 and the relevant caspase-3 could improve hippocampal neurogenesis and ameliorate radiation-induced cognitive dysfunction needs further exploration. We hypothesized that inhibition of the Cdk5/caspase-3 pathway by p5-TAT could protect hippocampal neurogenesis and alleviate radiation-induced cognitive dysfunction. In our study, we reported that radiation induced hyperactivity of Cdk5 accompanied by elevation of the levels of cleaved caspase-3, a marker of neuronal apoptosis. Inhibition of hippocampal neurogenesis and proliferation as well as cognitive dysfunction was also observed. p5-TAT, a specific inhibitor of Cdk5, decreased the overactivation of Cdk5 without affecting the levels of Cdk5 activators. Additionally, this treatment suppressed the expression of cleaved caspase-3. We further demonstrated that p5-TAT treatment reduced hippocampal dysfunction and improved behavioral performance. Therefore, Cdk5 inhibition by the small peptide p5-TAT is a promising therapeutic strategy for radiation-induced cognitive dysfunction.
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Affiliation(s)
- Junjun Zhang
- Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University, Suzhou City, China; Institute of Radiotherapy and Oncology, Soochow University, China; Suzhou Key Laboratory for Radiation Oncology, China
| | - Yujuan Zhang
- Experiment Center, Medicine College of Soochow University, Suzhou City, China
| | - Meiling Xu
- Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University, Suzhou City, China; Institute of Radiotherapy and Oncology, Soochow University, China; Suzhou Key Laboratory for Radiation Oncology, China
| | - Zhigang Miao
- Institute of Neuroscience, Soochow University, Suzhou City, China.
| | - Ye Tian
- Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University, Suzhou City, China; Institute of Radiotherapy and Oncology, Soochow University, China; Suzhou Key Laboratory for Radiation Oncology, China.
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Erkanli Senturk G, Cilingir-Kaya OT, Sirvanci S, Isler C, Kemerdere R, Ulu MO, Umay C, Onat F, Ozkara C, Uzan M, Ercan F. Ultrastructural investigation of synaptic alterations in the rat hippocampus after irradiation and hyperthermia. Ultrastruct Pathol 2020; 44:372-378. [PMID: 33121293 DOI: 10.1080/01913123.2020.1839151] [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] [Indexed: 10/23/2022]
Abstract
This study aimed to investigate ultrastructural synaptic alterations in rat hippocampus after in utero exposure to irradiation (IR) and postnatal exposure to hyperthermia (HT). There were four groups in each of the time points (3rd and 6th months). IR group: Pregnant rats were exposed to radiation on the 17th gestational day. HT group: Hyperthermia was applied to the rat pups on the 10th day after their birth. IR+HT group: Both IR and HT were applied at the same time periods. Control group: No IR or HT was applied. Rat pups were sacrificed after 3 and 6 months. Thin sections from the dentate gyrus (DG) and the CA3 of hippocampus were evaluated for synapse numbers by electron microscopy. Synapses were counted, and statistical analysis was performed. Abnormalities in myelin sheath, mossy terminals and neuropil were observed in the CA3 and DG of all groups. The synapses in the CA3 region were significantly increased in the IR-3rd month, IR-6th month, and IR+HT-3rd month groups vs control group. Synapses were significantly increased in the DG of HT-3rd month group. A trend for an increase in synapse numbers was seen in the CA3 and DG. Increased number of synapses in the rat hippocampus may be due to mossy fiber sprouting, possibly caused by in utero irradiation and/or postnatal hyperthermia.
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Affiliation(s)
- Gozde Erkanli Senturk
- Cerrahpasa Faculty of Medicine, Department of Histology and Embryology, Istanbul University-Cerrahpasa , Istanbul, Turkey
| | | | - Serap Sirvanci
- Department of Histology and Embryology, School of Medicine, Marmara University , Istanbul, Turkey
| | - Cihan Isler
- Cerrahpasa Faculty of Medicine, Department of Neurosurgery, Istanbul University-Cerrahpasa , Istanbul, Turkey
| | - Rahsan Kemerdere
- Cerrahpasa Faculty of Medicine, Department of Neurosurgery, Istanbul University-Cerrahpasa , Istanbul, Turkey
| | - Mustafa Onur Ulu
- Cerrahpasa Faculty of Medicine, Department of Neurosurgery, Istanbul University-Cerrahpasa , Istanbul, Turkey
| | - Cenk Umay
- Department of Radiation Oncology, School of Medicine, Dokuz Eylul University , Izmir, Turkey
| | - Filiz Onat
- Department of Pharmacology and Clinical Pharmacology, School of Medicine, Marmara University , Istanbul, Turkey
| | - Cigdem Ozkara
- Cerrahpasa Medical Faculty, Department of Neurology, Istanbul University-Cerrahpasa , Istanbul, Turkey
| | - Mustafa Uzan
- Cerrahpasa Faculty of Medicine, Department of Neurosurgery, Istanbul University-Cerrahpasa , Istanbul, Turkey
| | - Feriha Ercan
- Department of Histology and Embryology, School of Medicine, Marmara University , Istanbul, Turkey
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Ji S, Wu H, Ding X, Chen Q, Jin X, Yu J, Yang M. Increased hippocampal TrkA expression ameliorates cranial radiation‑induced neurogenesis impairment and cognitive deficit via PI3K/AKT signaling. Oncol Rep 2020; 44:2527-2536. [PMID: 33125501 PMCID: PMC7640353 DOI: 10.3892/or.2020.7782] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 09/01/2020] [Indexed: 01/13/2023] Open
Abstract
Cognitive deficit is one of the most serious complications of cranial radiotherapy of head and neck cancers. However, the underlying mechanism of this cognitive impairment remains unclear. In the present study, the role of tropomyosin receptor kinase A (TrkA) and its ligand neurotrophin nerve growth factor (NGF) were investigated following whole-brain irradiation (WBI). Young male Sprague-Dawley rats underwent WBI at a single dose of 10 Gy. WBI was determined to result in notable memory decline and substantial neurogenesis impairment in the hippocampus 3 months post-irradiation. Compared with the control group, TrkA protein expression was greater in irradiated rats 1 week after WBI, which then decreased significantly by the 3-month time-point. However, no difference in NGF expression was observed from 1 day to 3 months post-WBI. Overexpression of hippocampal TrkA in rats using adeno-associated virus ameliorated memory decline induced by irradiation. Additionally, upregulating TrkA expression rescued irradiation-induced hippocampal precursor cell proliferation and promoted neurogenesis. PI3K, Akt and ERK1/2 phosphorylation were also revealed to be significantly inhibited by WBI, which was ameliorated by TrkA overexpression. Findings of the present study indicated that the TrkA-dependent signaling pathway may serve a critical role in radiotherapy-induced cognitive deficit and impairments in neurogenesis.
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Affiliation(s)
- Shengjun Ji
- Clinical College, School of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
| | - Haohao Wu
- Department of Radiotherapy and Oncology, Yancheng No. 1 People's Hospital, Yancheng, Jiangsu 224000, P.R. China
| | - Xin Ding
- Department of Radiotherapy and Oncology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221000, P.R. China
| | - Qingqing Chen
- Department of Radiotherapy and Oncology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu 215001, P.R. China
| | - Xing Jin
- Department of Radiotherapy and Oncology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu 215001, P.R. China
| | - Jinming Yu
- Clinical College, School of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
| | - Ming Yang
- Shandong Academy of Medical Sciences, Shandong First Medical University, Jinan, Shandong 250117, P.R. China
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Wang L, Tian M, Hao Y. Role of p75 neurotrophin receptor in neuronal autophagy in intracerebral hemorrhage in rats through the mTOR signaling pathway. Cell Cycle 2020; 19:376-389. [PMID: 31924125 DOI: 10.1080/15384101.2019.1711318] [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] [Indexed: 10/25/2022] Open
Abstract
Rupture of weakened blood vessels could lead to severe intracerebral hemorrhage (ICH) and brain injuries. This study was designed to explore the roles of p75 neurotrophin receptor (p75NTR) in neuronal autophagy in ICH rats. An ICH rat model was established, and then gain and loss of functions of p75NTR in rat tissues were performed. Then, the pathologic morphology, water content, and inflammation in brain tissues were assessed. Western blot analysis was applied to detect the levels of inflammatory proteins, apoptosis- and autophagy-related proteins, and the mammalian target of rapamycin (mTOR) pathway-related proteins. Neuronal autophagy was further measured with mTOR activated. In vitro experiments were also performed on brain microvascular endothelial cells (BMECs) and astrocytes. Consequently, we found p75NTR knockdown improved the pathologic morphology with reduced neuron damage, water content, permeability of blood-brain barrier and inflammation in ICH rat brain tissues. Besides, Knockdown of p75NTR decreased neuronal apoptosis and inactivated mTOR signaling pathway, but it elevated the levels of autophagy-related proteins. In vivo results were reproduced in in vitro experiments. This study demonstrated that knockdown of p75NTR could promote neuronal autophagy and reduce neuronal apoptosis via inactivating the mTOR pathway. We hope these findings could provide new therapeutic options for ICH treatment.
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Affiliation(s)
- Lei Wang
- Department of emergency medicine, Zaozhuang Municipal Hospital, Zaozhuang, Shandong, P.R. China
| | - Meilei Tian
- Department of emergency medicine, Zaozhuang Municipal Hospital, Zaozhuang, Shandong, P.R. China
| | - Yugui Hao
- Department of emergency medicine, Zaozhuang Municipal Hospital, Zaozhuang, Shandong, P.R. China
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Simmons DA, Lartey FM, Schüler E, Rafat M, King G, Kim A, Ko R, Semaan S, Gonzalez S, Jenkins M, Pradhan P, Shih Z, Wang J, von Eyben R, Graves EE, Maxim PG, Longo FM, Loo BW. Reduced cognitive deficits after FLASH irradiation of whole mouse brain are associated with less hippocampal dendritic spine loss and neuroinflammation. Radiother Oncol 2019; 139:4-10. [DOI: 10.1016/j.radonc.2019.06.006] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 05/28/2019] [Accepted: 06/07/2019] [Indexed: 01/21/2023]
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