Implications for oxidative stress and astrocytes following 26S proteasomal depletion in mouse forebrain neurones

Abstract

Neurodegenerative diseases are characterized by progressive degeneration of selective neurones in the nervous system, but the underlying mechanisms involved in neuroprotection and neurodegeneration remain unclear. Dysfunction of the ubiquitin proteasome system is one of the proposed hypotheses for the cause and progression of neuronal loss. We have performed quantitative two-dimensional fluorescence difference in-gel electrophoresis combined with peptide mass fingerprinting to reveal proteome changes associated with neurodegeneration following 26S proteasomal depletion in mouse forebrain neurones. Differentially expressed proteins were validated by Western blotting, biochemical assays and immunohistochemistry. Of significance was increased expression of the antioxidant enzyme peroxiredoxin 6 (PRDX6) in astrocytes, associated with oxidative stress. Interestingly, PRDX6 is a bifunctional enzyme with antioxidant peroxidase and phospholipase A2 (PLA2) activities. The PLA2 activity of PRDX6 was also increased following 26S proteasomal depletion and may be involved in neuroprotective or neurodegenerative mechanisms. This is the first in vivo report of oxidative stress caused directly by neuronal proteasome dysfunction in the mammalian brain. The results contribute to understanding neuronal-glial interactions in disease pathogenesis, provide an in vivo link between prominent disease hypotheses and importantly, are of relevance to a heterogeneous spectrum of neurodegenerative diseases.

Increased plasma levels of phospholipid in Parkinson’s disease with mild cognitive impairment

“…Many potential factors can cause a state of oxidative stress in PD including mitochondrial dysfunction, increased free ion levels and reductions in antioxidant defense system functions [10,11]. Another possible mechanism is endogenous metabolic products, such as nitric oxide, reactive oxygen species, active ions, and toxicophores, along with deregulation of the ubiquitin-proteasome system, affecting the function of the respiratory chain in mitochondria and causing disorders of mitochondria and energy metabolism [12,13]. Also, decreased glucose uptake by the cerebral cortex and decreased blood perfusion in the frontal, temporal and parietal lobes can activate phospholipases, causing lysis of membrane PL [14,15].…”

Effect of sodium fluoride on male mouse fertility

“…Quantitative detection of cellular ROS was performed using the oxidation-sensitive fluorescent dye DCFDA (Abcam, Cambridge, UK) according to previously described method (Elkharaz et al, 2013;Rahman et al, 2014b). Finally the fluorescence activity of treated and control samples were detected using a microplate fluorometer (Gemini Em; Molecular Devices, Sunnyvale, CA, USA) and calculated by SoftMax Pro 5 (Molecular Devices).…”

Sodium nitroprusside suppresses male fertility in vitro

“…Cellular ROS was measured using the oxidation-sensitive fluorescent dye 2 0 ,7 0 -dichlorofluorescin diacetate (DCFDA) (Abcam, Cambridge, UK) according to the manufacturer's directions and a previously described method (Elkharaz et al, 2013). The DCFDA mix, 19 buffer, and 19 supplemental buffer were prepared according to the manufacturer's directions.…”