Protoemics on HIPPOCAMPi FROM PARTIAL-BODY IRRADIATED MICE

ABSTRACT: Background: The brain undergoes ionizing radiation exposure in many clinical situations, particularly during radiotherapy for brain tumors. The critical role of hippocampus in the pathogenesis of radiation-induced neurocognitive dysfunction is well recognized. Aim: The goal of this study is to test the potential contribution of non-targeted effects in the detrimental response of hippocampus to irradiation and to elucidate the mechanisms involved. Material and Methods: C57Bl/6 mice were whole body (WBI) or partial body (PBI) irradiated with 0.1 or 2.0 Gy of X-rays or sham irradiated. PBI consisted in the exposure of the lower third of the mouse body, whilst the upper two thirds were shielded. Hippocampi were collected 15 days or 6 months post-irradiation and a multi-omics approach was adopted to assess the molecular changes in non-coding RNAs, proteins and metabolic levels, as well as histological changes in the rate of hippocampal neurogenesis. Results: Notably, at 2.0 Gy the pattern of early molecular and histopathological changes induced in the hippocampus at 15 days following PBI was similar in quality and quantity to the effects induced by WBI, thus providing a proof of principle of the existence of out-of-target radiation response in the hippocampus of conventional mice. We detected major alterations in DAG/IP3 and TGF- signaling pathways as well as in the expression of proteins involved in the regulation of long-term neuronal synaptic plasticity and synapse organization, coupled with defects in NSCs self-renewal in the hippocampal dentate gyrus. However, compared to the persistence of the WBI effects, most of the PBI effects were only transient and tended to decrease at 6 months post-irradiation, indicating important mechanistic difference. On the contrary, at low dose we identified a progressive accumulation of molecular defects that tended to manifest at later post-irradiation times. These data, indicating that both targeted and non-targeted radiation effects might contribute to the pathogenesis of hippocampal radiation-damage, have general implications for human health

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Brain, Hippocampal Formation

SUBMITTER: Christine von Toerne  

LAB HEAD: Mariateresa Mancuso

PROVIDER: PXD024975 | Pride | 2021-09-10

REPOSITORIES: Pride