Project description:Traumatic brain injuries (TBI) of varied types are common across all populations and can cause visual problems. For military personnel in combat settings, injuries from blast exposures (bTBI) are prevalent and arise from a myriad of different situations. To model these diverse conditions, we are one of several groups modeling bTBI using mice in varying ways. Here, we report a refined analysis of retinal ganglion cell (RGC) damage in male C57BL/6J mice exposed to a blast-wave in an enclosed chamber. Ganglion cell layer thickness, RGC density (BRN3A and RBPMS immunoreactivity), cellular density of ganglion cell layer (hematoxylin and eosin staining), and axon numbers (paraphenylenediamine staining) were quantified at timepoints ranging from 1 to 17-weeks. RNA sequencing was performed at 1-week and 5-weeks post-injury. Earliest indices of damage, evident by 1-week post-injury, are a loss of RGC marker expression, damage to RGC axons, and increase in glial markers expression. Blast exposure caused a loss of RGC somas and axons-with greatest loss occurring by 5-weeks post-injury. While indices of glial involvement are prominent early, they quickly subside as RGCs are lost. The finding that axonopathy precedes soma loss resembles pathology observed in mouse models of glaucoma, suggesting similar mechanisms.
Project description:Traumatic brain injuries (TBI) of varied types are common across all populations and can cause visual problems. For military personnel in combat settings, injuries from blast exposures (bTBI) are prevalent and arise from a myriad of different situations. To model these diverse conditions, we are one of several groups modeling bTBI using mice in varying ways. Here, we report a refined analysis of retinal ganglion cell (RGC) damage in male C57BL/6J mice exposed to a blast-wave in an enclosed chamber. Ganglion cell layer thickness, RGC density (BRN3A and RBPMS immunoreactivity), cellular density of ganglion cell layer (hematoxylin and eosin staining), and axon numbers (paraphenylenediamine staining) were quantified at timepoints ranging from 1 to 17-weeks. RNA sequencing was performed at 1-week and 5-weeks post-injury. Earliest indices of damage, evident by 1-week post-injury, are a loss of RGC marker expression, damage to RGC axons, and increase in glial markers expression. Blast exposure caused a loss of RGC somas and axons-with greatest loss occurring by 5-weeks post-injury. While indices of glial involvement are prominent early, they quickly subside as RGCs are lost. The finding that axonopathy precedes soma loss resembles pathology observed in mouse models of glaucoma, suggesting similar mechanisms.
Project description:DNA damage plays a major role in neural cell death by necrosis and/or apoptosis. However, our understanding of the molecular mechanisms of neural cell death remains still incomplete. To acquire a global understanding of the various mediators related to DNA damage-induced neural cell death pathways, we performed a whole genomic wide screen in neural stem cells by using a siRNA library. We identified 80 genes required for DNA damage-induced cell death. 14 genes (17.5%) are directly related to cell death and/or apoptosis. 66 genes have not been previously directly linked to DNA damage-induced cell death. Using an integrated approach with functional and bioinformatics analysis, we have uncovered a molecular network containing several partially overlapping and interconnected pathways and/or protein complexes that are required for DNA damage-induced neural cell death. The identification of the network of neural cell death mediators will greatly enhance our understanding of the molecular mechanisms of neural cell death and provide therapeutic targets for nervous system disorders.
Project description:The eye is highly susceptible to inflammation-mediated tissue damage evoked during bacterial infection. We observed the itaconate as one of the highly induced metabolites in mouse retina and activated macrophages, yet its functional significance remains unknown in ocular infections.
Project description:These data show differences in up- and down-regulation for protein abundances in the hippocampus of double blast vs. sham rats. Tandem mass tags (TMT)-MS results showed 136 up-regulated and 94 down-regulated proteins between the two groups. These TMT-MS findings revealed changes never described before in blast studies. In the absence of behavioral changes, these proteomic data further support the existence of an asymptomatic blast-induced molecular altered status (ABIMAS) associated with specific protein changes in the rat hippocampus.
Project description:The DNA damage response is essential for preserving genome integrity and eliminating damaged cells. Although cellular metabolism plays a central role in cell fate decision between proliferation, survival or death, the metabolic response to DNA damage remains largely obscure. Here, we show that DNA damage induces fatty acid oxidation (FAO), which is required for DNA damage-induced cell death. Mechanistically, FAO induction increases cellular acetyl-CoA levels and promotes N-alpha-acetylation of caspase-2, leading to cell death. Whereas chemotherapy increases FAO related genes through PPARα, accelerated hypoxia-inducible factor-1α stabilization by tumor cells in obese mice impedes the upregulation of FAO, which contributes to its chemoresistance. Finally, we find that improving FAO by PPARα activation ameliorates obesity-driven chemoresistance and enhances the outcomes of chemotherapy in obese mice. These findings reveal the shift toward FAO induction is an important metabolic response to DNA damage and may provide effective therapeutic strategies for cancer patients with obesity.
Project description:Tissue damage precedes GvHD and the events leading up to this inflammatory disease are not well understood. To identify cell populations that may invade the intestinal tract after total body irradiation (TBI), we performed a microarray based gene expression analysis of the intestinal tract isolated from untreated mice or mice that had received 9 Gray TBI 24 h or 48 h previously. The aim of the microarray based gene expression analysis was to identify genes specific for certain cell populations that may contribute to GvHD.
Project description:Primary blast-induced mild traumatic brain injury (mTBI) represents a common injury experienced during modern warfare. With virtually no apparent physical damage or symptoms presented, an effective source with minimum-invasion for mTBI biomarker discovery is required. In this study, we measure the transcriptomic sensitivity of the hair follicles in relation to the severity of primary blast-derived TBI.
Project description:BMI1 is a polycomb protein and its overexpression has been correlated with cancer development and aggressiveness. We previously reported that v-myc avian myelocytomatosis viral oncogene neuroblastoma-derived homolog (MYCN)-induced BMI1 positively regulated neuroblastoma (NB) cell proliferation via the transcriptional suppression of tumor suppressors in NB cells. In order to evaluate the potential of BMI1 as a new target for NB therapy, we herein examined the effects of BMI1 reductions on NB cell differentiation and apoptotic NB cell death. BMI1 knockdown (KD) up to 7 days in NB cells significantly induced their differentiation. BMI1 depletion up to 14 days significantly induced apoptotic NB cell death along with the activation of p53, increases in p73, and induction of p53 family downstream molecules. BMI1 depletion in vivo markedly suppressed NB xenograft tumor growth. A pathological analysis using the TUNEL assay indicated the induction of apoptotic cell death. BMI1 reductions activated ATM and increased γ-H2AX in NB cells. Importantly, these DNA damage signals and apoptotic cell death were not canceled by transduction of polycomb group molecules EZH2 and RING1B. Further, EZH2 or RING1B knockdown could not induce apoptotic NB cell death at the same level of BMI1 KD. Together, BMI1 appears to be a promising target of molecular therapy for NB tumors and our report clarified, for the first time, the shared role of PcG proteins in DNA damage response of NB cells.