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RalBP1 (Rlip) is a stress-activated protein that is believed to play a large role in aging and neurodegenerative diseases such as Alzheimer's disease (AD) and other tauopathies. The purpose of our study was to understand the role of Rlip in mutant Tau-expressed immortalized hippocampal HT22 cells. In the current study, we used mutant Tau (mTau)-expressed HT22 neurons and HT22 cells transfected with Rlip-cDNA and/or silenced RNA, and studied the cell survival, mitochondrial respiration, mitochondrial function, immunoblotting, and immunofluorescence analysis of synaptic and mitophagy proteins and the colocalization of Rlip and mTau proteins. We found Rlip protein levels were reduced in mTau-HT22 cells, Rlip silenced HT22 cells, and mTau + Rlip RNA silenced HT22 cells; on the other hand, increased Rlip levels were observed in Rlip cDNA transfected HT22 cells. We found cell survival was decreased in mTau-HT22 cells and RNA-silenced HT22 cells. However, cell survival was increased in Rlip-overexpressed mTau-HT22 cells. A significantly reduced oxygen consumption rate (OCR) was found in mTau-HT22 cells and in RNA-silenced Rlip-HT22 cells, with an even greater reduction in mTau-HT22 + Rlip RNA-silenced HT22 cells. A significantly increased OCR was found in Rlip-overexpressed HT22 cells and in all groups of cells that overexpress Rlip cDNA. Mitochondrial function was defective in mTau-HT22 cells, RNA silenced Rlip in HT22 cells, and was further defective in mTau-HT22 + Rlip RNA-silenced HT22 cells; however, it was rescued in Rlip overexpressed in all groups of HT22 cells. Synaptic and mitophagy proteins were decreased in mTau-HT22 cells, and further reductions were found in RNA-silenced mTau-HT22 cells. However, these were increased in mTau + Rlip-overexpressed HT22 cells. An increased number of mitochondria and decreased mitochondrial length were found in mTau-HT22 cells. These were rescued in Rlip-overexpressed mTau-HT22 cells. These observations strongly suggest that Rlip deficiency causes oxidative stress/mitochondrial dysfunction and Rlip overexpression reverses these defects. Overall, our findings revealed that Rlip is a promising new target for aging, AD, and other tauopathies/neurological diseases. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is the most common cause of dementia in older people. AD is associated with the loss of synapses, oxidative stress, mitochondrial structural and functional abnormalities, microRNA deregulation, inflammatory responses, neuronal loss, accumulation of amyloid-beta (Aβ) and phosphorylated tau (p-tau). AD occurs in two forms: early onset, familial AD and late-onset, sporadic AD. Causal factors are still unknown for a vast majority of AD patients. Genetic polymorphisms are proposed to contribute to late-onset AD via age-dependent increases in oxidative stress and mitochondrial abnormalities. Recent research from our lab revealed that reduced levels of Rlip76 induce oxidative stress, mitochondrial dysfunction and synaptic damage, leading to molecular and behavioral phenotypes resembling late-onset AD. Rlip76 is a multifunctional 76 kDa protein encoded by the RALBP1 gene, located on chromosome 18. Rlip is a stress-protective ATPase of the mercapturic acid pathway that couples clathrin-dependent endocytosis with the efflux of glutathione–electrophile conjugates. Rlip is evolutionarily highly conserved across species and is ubiquitously expressed in all tissues, including AD-affected brain regions, the cerebral cortex and hippocampus, where highly active neuronal metabolisms render the cells highly susceptible to intracellular oxidative damage. In the current article, we summarize molecular and cellular features of Rlip and how depleted Rlip may exacerbate oxidative stress, mitochondrial dysfunction and synaptic damage in AD. We also discuss the possible role of Rlip in aspects of learning and memory via axonal growth, dendritic remodeling, and receptor regulation. We conclude with a discussion of the potential for the contribution of genetic polymorphisms in Rlip to AD progression and the potential for Rlip-based therapies. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a devastating illness in elderly individuals, that currently has no known cure. Causal genetic factors only account for 1-2% of AD patients. However, other causal factors are still unknown for a majority of AD patients. Currently, multiple factors are implicated in late-onset AD, including unhealthy diet, physical inactivity, traumatic brain injury, chronic conditions, epigenetic factors, and environmental exposures. Although clinical symptoms of dementia are common to all races and ethnic groups, conditions that lead to dementia are different in terms of lifestyle, genetic profile, and socio-economic conditions. Increasing evidence also suggests that some elderly individuals age without cognitive impairments in their 60-90s as seen in rural West Texas, while some individuals progress with chronic conditions and cognitive impairments into their 60s. To understand these discriminations, we assessed current literature on demographic features of health in rural West Texas. This paper also outlines our initiated clinical study with a purpose of understanding the factors that allow some individuals to live without cognitive impairments at the age of 60-90 years, whereas others develop deficits in cognitive function around or above 60 years. Our ongoing study hopes to determine the factors that delay aging in some individuals by investigating various aspects including genetics, epigenetics, ethnicity, biology, culture, and lifestyle. This will be achieved by gathering information about participants' ethnographic profiles, cognitive assessments, blood-profiles, brain scans, and blood-based genomic analyses in relation to lifestyle. The outcomes of our study will provide insights into healthy aging in rural West Texas. [ABSTRACT FROM AUTHOR]

• Pharmacokinetic analysis revealed high peak levels of DDQ in the skeletal muscle, followed by serum and brain. • Behavioral analysis revealed that DDQ ameliorated cognitive decline, improved working memory, exploratory behavior, and motor coordination in in APP mice. • DDQ enhances SIRTUINS, mitochondrial biogenesis, fusion, mitophagy, autophagy and synaptic genes in APP mice. • Dendritic spines and the quality mitochondria were significantly increased in DDQ treated APP mice. The purpose of our study is to determine the protective effects of the newly discovered molecule DDQ (diethyl (3,4-dihydroxyphenethylamino)(quinolin-4-yl) methylphosphonate) against mutant APP and amyloid-beta (Aβ) in Alzheimer's disease (AD). To achieve our objective, we used a well characterized amyloid-beta precursor protein (APP) transgenic mouse model (Tg2576 strain). We administered DDQ, a 20 mg/kg body weight (previously determined in our laboratory) intra-peritoneally 3-times per week for 2 months, starting at the beginning of the 12th month, until the end of the 14th month. Further, using biochemical and molecular methods, we measured the levels of DDQ in the blood, skeletal muscle, and brain. Using Morris Water Maze, Y-maze, open field, and rotarod tests, we assessed cognitive behavior after DDQ treatment. Using q-RT-PCR, immunoblotting, transmission electron microscopy, and Golgi-cox staining methods, we studied mRNA and protein levels of longevity genes SIRTUINS, mitochondrial number & length, and dendritic spine number and length in DDQ-treated APP mice. Our extensive pharmacodynamics analysis revealed high peak levels of DDQ in the skeletal muscle, followed by serum and brain. Our behavioral analysis of rotarod, open field, Y-maze, and Morris Water Maze tests revealed that DDQ ameliorated cognitive decline (Morris Water Maze), improved working memory (Y-Maze), exploratory behavior (open field), and motor coordination (rotarod) in DDQ-treated APP mice. Interestingly, longevity genes SIRTUINS, mitochondrial biogenesis, fusion, mitophagy, autophagy and synaptic genes were upregulated in DDQ-treated APP mice relative to untreated APP mice. Dendritic spines and the quality mitochondria were significantly increased in DDQ treated APP mice. Current study findings, together with our previous study observations, strongly suggest that DDQ has anti-aging, and anti-amyloid-beta effects and a promising molecule to reduce age-and amyloid-beta-induced toxicities in AD. [ABSTRACT FROM AUTHOR]

Several converging lines of evidence from our group support a potential role of RLIP76 (AKA Rlip) in neurodegenerative disorders, including Alzheimer's Disease (AD). However, the role of Rlip in Alzheimer's and other neurodegenerative diseases is not well understood. The purpose of the present study is to determine the role of Rlip in the brains of AD patients and control subjects. To achieve our goals, we used frozen tissues and formalin-fixed paraffin-embedded postmortem brains from AD patients of different Braak stages and age-matched control subjects. Our immunohistology and immunoblotting blotting analysis revealed that expression of Rlip protein gradually and significantly decreased (p = 0.0001) with AD progression, being lowest in Braak stage IV-V. Rlip was colocalized with Amyloid beta (Aβ) and phosphorylated tau (p-Tau) as observed by IHC staining and co-immunoprecipitation studies. Lipid peroxidation (4-HNE generation) and H 2 O 2 production were significantly higher (p = 0.004 and 0.0001 respectively) in AD patients compared to controls, and this was accompanied by lower ATP production in AD (p = 0.0009). Oxidative DNA damage was measured by 8-Hydroxyguanosine (8-OHdG) in tissue lysates by ELISA and COMET assay. AD 8-OHdG levels were significantly higher (p = 0.0001) compared to controls. COMET assay was performed in brain cells, isolated from frozen postmortem samples. The control samples showed minimal DNA in comets representing few DNA strand breaks (<20 %), (score-0-1). However, the AD group showed an average of 50 % to 65 % of DNA in comet tails (score-4-5) indicating numerous DNA strand breaks. The difference between the two groups was significant (p = 0.001), as analyzed by Open Comet by ImageJ. Elevated DNA damage was further examined by western blot analysis for phosphorylated histone variant H2AX (γH2AX). Induction of γH2AX was very significant (p < 0.0001) and confirmed the presence of double-strand breaks in DNA. Overall, our results indicate an important role for Rlip in maintaining neuronal health and homeostasis by suppressing cellular oxidative stress and DNA damage. Based on our findings, we cautiously conclude that Rlip is a promising therapeutic target for Alzheimer's disease. • Increasing evidence suggest that a potential role of RLIP76 in neurodegenerative disorders, including Alzheimer's Disease • Expression of Rlip protein gradually and significantly decreased with AD progression • Rlip was colocalized with Amyloid beta and phosphorylated tau. • Reduction of Rlip is correlated with increased oxidative DNA damage and mitochondrial dysfunction in AD patients • Rlip is a promising therapeutic target for Alzheimer's disease. [ABSTRACT FROM AUTHOR]

• The steroidogenic acute regulatory (StAR) protein mediates neurosteroidogenesis that progressively deteriorates during human senescence. • We observed that postmortem brains of Alzheimer's disease (AD) patients exhibit suppression of StAR, free cholesterol (FC), and pregnenolone levels. • Attenuation of the steroidogenic response in AD brains was inversely correlated with Aβ and pTau accumulation. • Our findings demonstrate that downregulation of StAR governed neurosteroidogenesis correlated with aggregation of APP/Aβ and pTau in AD. [ABSTRACT FROM AUTHOR]

The purpose of our study is to understand the role of the RALBP1 gene in oxidative stress (OS), mitochondrial dysfunction and cognition in Alzheimer's disease (AD) pathogenesis. The RALPB1 gene encodes the 76 kDa protein RLIP76 (Rlip). Rlip functions as a stress-responsive/protective transporter of glutathione conjugates (GS-E) and xenobiotic toxins. We hypothesized that Rlip may play an important role in maintaining cognitive function. The aim of this study is to determine whether Rlip deficiency in mice is associated with AD-like cognitive and mitochondrial dysfunction. Brain tissue obtained from cohorts of wildtype (WT) and Rlip+/− mice were analyzed for OS markers, expression of genes that regulate mitochondrial fission/fusion, and synaptic integrity. We also examined mitochondrial ultrastructure in brains obtained from these mice and further analyzed the impact of Rlip deficiency on gene networks of AD, aging, stress response, mitochondrial function, and CREB signaling. Our studies revealed a significant increase in the levels of OS markers and alterations in the expression of genes and proteins involved in mitochondrial biogenesis, dynamics and synapses in brain tissues from these mice. Furthermore, we compared the cognitive function of WT and Rlip+/− mice. Behavioral, basic motor and sensory function tests in Rlip+/− mice revealed cognitive decline, similar to AD. Gene network analysis indicated dysregulation of stress-activated gene expression, mitochondrial function and CREB signaling genes in the Rlip+/− mouse brain. Our results suggest that Rlip deficiency-associated increases in OS and mitochondrial dysfunction could contribute to the development or progression of OS-related AD processes. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a neurodegenerative disease that affects a large proportion of the aging population. RalBP1 (Rlip) is a stress-activated protein that plays a crucial role in oxidative stress and mitochondrial dysfunction in aging and neurodegenerative diseases but its precise role in the progression of AD is unclear. The purpose of our study is to understand the role of Rlip in the progression and pathogenesis of AD in mutant APP/amyloid beta (Aβ)-expressed mouse primary hippocampal (HT22) hippocampal neurons. In the current study, we used HT22 neurons that express mAPP, transfected with Rlip-cDNA and/or RNA silenced, and studied cell survival, mitochondrial respiration, mitochondrial function, immunoblotting & immunofluorescence analysis of synaptic and mitophagy protein's and colocalization of Rlip and mutant APP/Aβ proteins and mitochondrial length and number. We also assessed Rlip levels in autopsy brains from AD patients and control subjects. We found cell survival was decreased in mAPP-HT22 cells and RNA-silenced HT22 cells. However, cell survival was increased in Rlip-overexpressed mAPP-HT22 cells. Oxygen consumption rate (OCR) was decreased in mAPP-HT22 cells and RNA-silenced Rlip-HT22 cells. OCR was increased in Rlip-overexpressed in mAPP-HT22 cells. Mitochondrial function was defective in mAPP-HT22 cells and RNA silenced Rlip in HT22 cells, however, it was rescued in Rlip overexpressed mAPP-HT22 cells. Synaptic and mitophagy proteins were decreased in mAPP-HT22 cells, further reducing RNA-silenced Rlip-HT22 cells. However, these were increased in mAPP+Rlip-HT22 cells. Colocalization analysis revealed Rlip is colocalized with mAPP/Aβ. An increased number of mitochondria and decreased mitochondrial length were found in mAPP-HT22 cells. These were rescued in Rlip overexpressed mAPP-HT22 cells. Reduced Rlip levels were found in autopsy brains from AD patients. These observations strongly suggest that Rlip deficiency causes oxidative stress/mitochondrial dysfunction and Rlip overexpression reduced these defects. • Alzheimer's disease (AD) is a neurodegenerative disease that affects a large proportion of the aging population. • RalBP1 (Rlip) is a stess-activated protein that plays a crucial role in oxidative stress and mitochondrial dysfunction. • Cell survival was decreased in mAPP-HT22 cells and RNA-silenced HT22 cells and cell survival was increased in Rlip-overexpressed mAPP-HT22 cells. • Oxygen consumption rate (OCR) was increased in Rlip-overexpressed in mAPP-HT22 cells. • Reduced Rlip levels were found in autopsy brains from AD patients. [ABSTRACT FROM AUTHOR]