Low dose cranial irradiation-induced cerebrovascular damage is reversible in mice

BACKGROUND: High-dose radiation-induced blood-brain barrier breakdown contributes to acute radiation toxicity syndrome and delayed brain injury, but there are few data on the effects of low dose cranial irradiation. Our goal was to measure blood-brain barrier changes after low (0.1 Gy), moderate (2 Gy) and high (10 Gy) dose irradiation under in vivo and in vitro conditions. METHODOLOGY: Cranial irradiation was performed on 10-day-old and 10-week-old mice. Blood-brain barrier permeability for Evans blue, body weight and number of peripheral mononuclear and circulating endothelial progenitor cells were evaluated 1, 4 and 26 weeks postirradiation. Barrier properties of primary mouse brain endothelial cells co-cultured with glial cells were determined by measurement of resistance and permeability for marker molecules and staining for interendothelial junctions. Endothelial senescence was determined by senescence associated β-galactosidase staining. PRINCIPLE FINDINGS: Extravasation of Evans blue increased in cerebrum and cerebellum in adult mice 1 week and in infant mice 4 weeks postirradiation at all treatment doses. Head irradiation with 10 Gy decreased body weight. The number of circulating endothelial progenitor cells in blood was decreased 1 day after irradiation with 0.1 and 2 Gy. Increase in the permeability of cultured brain endothelial monolayers for fluorescein and albumin was time- and radiation dose dependent and accompanied by changes in junctional immunostaining for claudin-5, ZO-1 and β-catenin. The number of cultured brain endothelial and glial cells decreased from third day of postirradiation and senescence in endothelial cells increased at 2 and 10 Gy. CONCLUSION: Not only high but low and moderate doses of cranial irradiation increase permeability of cerebral vessels in mice, but this effect is reversible by 6 months. In-vitro experiments suggest that irradiation changes junctional morphology, decreases cell number and causes senescence in brain endothelial cells

Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points

Minimal information for studies of extracellular vesicles 2018 (MISEV2018): a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points

Low Dose Radiation Induced Transcriptional Alterations in Directly Irradiated and Bystander Fibroblast Cells

Introduction: Formerly, we studied transcriptional alterations in primary human fibroblast cells after irradiation with 2 Gy (Kis et al. Int J Radiat Oncol Biol Phys. 66:1506-14. 2006). We found that about 200 genes responded to radiation and the expression profile depended on individual genetic backgrounds. Thirty consensus radiation response genes answered to radiation in identical manner in all investigated cells. Now, we have investigated low dose radiation induced transcriptional responses in directly hit and bystander cells. Methods: F11 primary human fibroblasts were irradiated with different doses (10, 40, 100 and 500 mGy) of 60Co gamma radiation. To investigate radiation-induced transcriptional alterations in directly irradiated cells, RNA was isolated 2 h after irradiation. To study responses in bystander cells the culture medium was removed from the irradiated cells 2 h after irradiation and transferred to unirradiated recipient cells. RNA was isolated 2 h later and the transcriptional profile analyzed by whole genome microarrays. Results: When cells were irradiated with 500 mGy 1119 genes responded to radiation. Ten of the formerly identified consensus radiation response genes changed its transcription (CDKN1A, TP53INP1, CYP26B1, BTG2, BBC3, PPM1D, THSD1, GDF15, NM_024661, BC010544). Irradiation of F11 fibroblasts with 100 and 10 mGy altered the transcription profile of 847 and 1414 genes, respectively. When we compared the transcription profile of cells irradiated with 500 and 100 mGy 377 similar alterations were detected, among them 6 consensus radiation response genes (CDKN1A, TP53INP1, GDF15, BTG2, BBC3, NM_024661) changed its transcription in an identical manner. One hundred and twenty-four genes responded to radiation after all applied doses. In bystander cells 655 and 406 genes responded to 500 and 100 mGy irradiations, respectively on the transcription level. After irradiation with 40 and 10 mGy the number of responding genes were 152 and 619, respectively. When we compared the responses in bystander cells after irradiation with 100 and 40 mGy only 40 genes responded identically. The comparison of the transcriptional profile of 40 and 10 mGy irradiated cells detected 60 similar responses. Altogether fifteen genes responded to all doses of radiation in bystander cells. Finally, we have detected nine genes (DLGAP4, HRASLS5, TMEM167, RPL23, RPL38, PRSS36, and three hypothetical proteins) responding to all doses of radiation both in directly irradiated and bystander cells. Conclusions: By the analysis of radiation induced transcriptional alterations one might find potential biomarkers suitable to detect low dose responses