Repeat-associated non-ATG (RAN) proteins have been reported in 11 microsatellite expansion disorders but the factors that allow RAN translation to occur and the effects of different repeat motifs and alternative AUG-like initiation codons are unclear. We studied the mechanisms of RAN translation across myotonic dystrophy type 2 (DM2) expansion transcripts with (CCUG) or without (CAGG) efficient alternative AUG-like codons. To better understand how DM2 LPAC and QAGR RAN proteins are expressed, we generated a series of CRISPR/Cas9-edited HEK293T cell lines.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
August 2020
Repeat associated non-AUG (RAN) translation is found in a growing number of microsatellite expansion diseases, but the mechanisms remain unclear. We show that RAN translation is highly regulated by the double-stranded RNA-dependent protein kinase (PKR). In cells, structured CAG, CCUG, CAGG, and GC expansion RNAs activate PKR, which leads to increased levels of multiple RAN proteins.
View Article and Find Full Text PDFThe intronic C9orf72 G4C2 expansion, the most common genetic cause of ALS and FTD, produces sense- and antisense-expansion RNAs and six dipeptide repeat-associated, non-ATG (RAN) proteins, but their roles in disease are unclear. We generated high-affinity human antibodies targeting GA or GP RAN proteins. These antibodies cross the blood-brain barrier and co-localize with intracellular RAN aggregates in C9-ALS/FTD BAC mice.
View Article and Find Full Text PDFHuntington disease (HD) is caused by a CAG ⋅ CTG expansion in the huntingtin (HTT) gene. While most research has focused on the HTT polyGln-expansion protein, we demonstrate that four additional, novel, homopolymeric expansion proteins (polyAla, polySer, polyLeu, and polyCys) accumulate in HD human brains. These sense and antisense repeat-associated non-ATG (RAN) translation proteins accumulate most abundantly in brain regions with neuronal loss, microglial activation and apoptosis, including caudate/putamen, white matter, and, in juvenile-onset cases, also the cerebellum.
View Article and Find Full Text PDFSalvia macilenta is a member of the genus Salvia (Laminaceae) whose antioxidant activity and neuroprotective effect has been shown previously. The present study aimed to examine the antiglycating and antiapoptotic abilities of methanolic extract of this plant. Moreover, the effect of S.
View Article and Find Full Text PDFNeurite outgrowth is an important aspect of neuronal plasticity and regeneration after neuronal injury. In this study we aimed to investigate the possible effect of 3-thiomethyl-5,6-dimethoxyphenyl-1,2,4-triazine (TDMT) on H(2)O(2)-induced impairment of neurite outgrowth. We found that TDMT could improve neurite outgrowth and neurite complexity in H(2)O(2)-exposed PC12 cells.
View Article and Find Full Text PDFMuch evidence supports that oxidative stress plays an important role in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease. Herein, we studied the compensatory/adaptive mechanisms involved in 3-thiomethyl-5,6-(diphenyl)-1,2,4-triazine and 3-thiomethyl-5,6-(dichlorophenyl)-1,2,4-triazine neuroprotection. We found that these compounds could counteract H(2)O(2)-induced rupture of neurite outgrowth in differentiated PC12 cells.
View Article and Find Full Text PDFSeveral studies have shown that neuronal cell death due to apoptosis is the major reason for cognitive decline in Alzheimer's disease. In this study, we report the anti-apoptotic effects of three Salvia species from Iran-S. choloroleuca, S.
View Article and Find Full Text PDFMost of the modulating effects of cannabinoids on pain are through putative cannabinoid CB1 and CB2 receptors. However, the involvement of other receptors is also suggested. Cannabinoid compounds with analgesic activity such as palmitoylethanolamide (PEA) show low affinity to CB1 and CB2 receptors, yet selectively activate GPR55 receptors.
View Article and Find Full Text PDFThis study was designed to examine antioxidant activities, antiglycating abilities and neuroprotective effects of methanolic extracts of Salvia choloroleuca, Salvia santolinifolia and Salvia mirzayanii from Iran. The extracts were screened for their possible antioxidant activities by several biochemical assays such as DPPH, FRAP, β-carotene bleaching and TEAC assays. HPLC analysis of these extracts led to the separation of a number of components such as catechine and rosmarinic acid.
View Article and Find Full Text PDFOxidative stress is a major component of harmful cascades activated in neurodegenerative disorders. We sought to elucidate possible effects of alginate oligosaccharide (AOS) on H(2)O(2)-induced cell death and to determine the underlying molecular mechanisms in neuron-like PC12 cells. We found that AOS treatment protected PC12 cells against H(2)O(2)-induced endoplasmic reticulum (ER) and mitochondrial-dependent apoptotic cell death.
View Article and Find Full Text PDFThe inflammatory reaction plays an important role in the pathogenesis of the neurodegenerative disorders. tert-butylhydroquinone (tBHQ) exhibits a wide range of pharmacological activities including anti-oxidative and anti-inflammatory action. In this study, we tried to elucidate possible effects of tBHQ on lipopolysaccharide (LPS)-induced inflammatory reaction and its underlying mechanism in neuron-like PC12 cells.
View Article and Find Full Text PDFIncreased oxidative stress is widely accepted to be a factor in the development and progression of Alzheimer's disease (AD). Here we introduced Salvia sahendica as a protective agent in differentiated PC12 cells, which are commonly considered to be a reliable model of neuronal cells. Our results demonstrated that S.
View Article and Find Full Text PDFNuclear factor erythroid 2-related factor 2 (Nrf2) coordinates the up-regulation of cytoprotective genes via the antioxidant response element (ARE). There is significant evidence that oxidative stress is a critical event in the pathogenesis of AD. Considering the protective role of Nrf2 against oxidative injury, we studied to determine whether in vivo toxicity of amyloid β (Aβ) can be attenuated by tBHQ, an Nrf2 stabilizer, Using an Aβ injection model.
View Article and Find Full Text PDFIn the present work we prepared chitosan-coated alginate beads, to use as a chemical chaperone based on the electrostatic interaction between the carboxylate groups of alginate and the ammonium groups of chitosan. This procedure was an attempt for designing a highly efficient chemical chaperone to improve protein stability and refolding. Based on enzyme recovered activity, turbidity, far-UV CD and fluorescence data, alkaline phosphatase can be stabilized and refolded to a higher degree in the presence of alginate capsules compared with unassisted form and was further improved by including chitosan.
View Article and Find Full Text PDFThe role of novel triazine derivatives against oxidative stress exerted by hydrogen peroxide on differentiated rat pheochromocytoma (PC12) cell line was examined and a consistent protection from H(2)O(2)-induced cell death, associated with a marked reduction in caspase-3 activation, was observed. Moreover, activation of NF-kappaB, a known regulator of a host of genes that involves in specific stress and inflammatory responses by H(2)O(2), was greatly impaired by triazine pretreatment in differentiated PC12 cells. Neuroprotective effect of such compounds may represent a promising approach for treatment of neurodegenerative diseases.
View Article and Find Full Text PDFOxidative stress has been implicated in the etiology of neurodegenerative diseases and aging. Indeed, accumulation of reactive oxygen species, such as hydrogen peroxide, generated by inflammatory cells, leads to oxidative stress, which may contribute to the neuronal degeneration observed in a wide variety of neurodegenerative disorders of the central nervous system, such as Alzheimer's disease. The present study indicates that H(2)O(2)-induced cell death can be inhibited in the presence of 1,2,4-triazine derivatives, as measured by MTT and caspase-3 activity.
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