Antisense oligonucleotide mediated therapy of spinal muscular atrophy

Spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality. SMA results from deletions or mutations of survival motor neuron 1 (SMN1), an essential gene. SMN2, a nearly identical copy, can compensate for SMN1 loss if SMN2 exon 7 skipping is prevented. Among the many cis-elements involved in the splicing regulation of SMN exon 7, intronic splicing silencer N1 (ISS-N1) has emerged as the most effective target for an antisense oligonucleotide (ASO)-mediated splicing correction of SMN2 exon 7. Blocking of ISS-N1 by an ASO has been shown to fully restore SMN2 exon 7 inclusion in SMA patient cells as well as in vivo. Here we review how ISS-N1 targeting ASOs that use different chemistries respond differently in the various SMA mouse models. We also compare other ASO-based strategies for therapeutic splicing correction in SMA. Given that substantial progress on ASO-based strategies to promote SMN2 exon 7 inclusion in SMA has been made, and that similar approaches in a growing number of genetic diseases are possible, this report has wide implications

Withania somnifera ameliorates nandrolone-decanoate-induced brain damage in rats by inhibiting cell death, prodynorphin mRNA expression and acetylcholinesterase activity

The misuse of anabolic-androgenic steroids by athletes and non-athletes causes harmful effects on the central nervous system. In Ayurvedic medicine, Withania somnifera (WS) as an herbal drug has been reported for several functions including adaptogenic, anticonvulsant, cytoprotective and antioxidant. The present study investigated the neuroprotective functions of WS (100, 200 and 400 mg/kg body weight) in nandrolone decanoate (ND)-induced (16 mg/kg body weight) brain injury in male Wistar rats. ND was injected intramuscularly twice weekly for 4 weeks. The water emulsion of WS root powder was administered orally once daily for 30 days to ND-treated rats. At the end of the experiment, anxiety-like behaviour was assessed in rats using the elevated plus maze. Haematoxylin-and-eosin-stained coronal sections of the parietal cortex and hippocampus of ND rats showed severe alterations in brain histology compared with control rats. Acetylcholinesterase (AChE) activity in the striatum and prodynorphin gene expression in the hippocampus was significantly elevated in the ND group compared with the control group. Treating ND induced rats with various doses of WS significantly reversed the brain damage, anxiety behaviour, increased striatal AChE activity and reduced prodynorphin gene expression in the hippocampus. In conclusion, WS extract can be used as a neuroprotective agent to reduce the effects of anabolic steroids

Withania somnifera ameliorates nandrolone-decanoate-induced brain damage in rats by inhibiting cell death, prodynorphin mRNA expression and acetylcholinesterase activity

685-693The misuse of anabolic-androgenic steroids by athletes and non-athletes causes harmful effects on the central nervous system. In Ayurvedic medicine, Withania somnifera (WS) as an herbal drug has been reported for several functions including adaptogenic, anticonvulsant, cytoprotective and antioxidant. The present study investigated the neuroprotective functions of WS (100, 200 and 400 mg/kg body weight) in nandrolone decanoate (ND)-induced (16 mg/kg body weight) brain injury in male Wistar rats. ND was injected intramuscularly twice weekly for 4 weeks. The water emulsion of WS root powder was administered orally once daily for 30 days to ND-treated rats. At the end of the experiment, anxiety-like behaviour was assessed in rats using the elevated plus maze. Haematoxylin-and-eosin-stained coronal sections of the parietal cortex and hippocampus of ND rats showed severe alterations in brain histology compared with control rats. Acetylcholinesterase (AChE) activity in the striatum and prodynorphin gene expression in the hippocampus was significantly elevated in the ND group compared with the control group. Treating ND induced rats with various doses of WS significantly reversed the brain damage, anxiety behaviour, increased striatal AChE activity and reduced prodynorphin gene expression in the hippocampus. In conclusion, WS extract can be used as a neuroprotective agent to reduce the effects of anabolic steroids

Inhibition of oxidative stress, inflammation and apoptosis by Terminalia arjuna against acetaminophen-induced hepatotoxicity in Wistar albino rats

51-57Overuse of therapeutic drugs such as acetaminophen often affects liver, and may lead to inflammatory mediated liver cell death. Here, we studied the effect of Terminalia arjuna (TA) bark against acetaminophen (APAP) induced liver cell death/injury by testing the antioxidant levels, oxidative stress, and inflammation and apoptosis markers. Wistar albino male rats weighing 180-280 mg/kg were made into 5 groups of 6 animals each and were treated as follows: Gr. I, control; Gr. II, acetaminophen (APAP); GR. III, N-acetylcysteine (NAC); Gr. IV & V, Terminalia arjuna (TA) 250 and mg/kg. The antioxidant glutathione (GSH), lipid peroxidation (MDA), interleukin 1β (IL-1β) levels, caspase-9 levels, and Protein kinase B (P-AKT) gene expression levels were assessed. The rGr. V animals pre-treated with Terminalia arjuna high dose bark showed increased glutathione (GSH) levels, but decreased malondialdehyde (MDA) levels; inhibited IL-1β and caspase-9 levels; and also elevated gene expression level of P-AKT to regulate the cell signaling pathway. Apparently, the results demonstrated that a high dose of TA 500 mg/kg ameliorated acetaminophen-induced hepatotoxicity

Oxidative Stress Triggers Body-Wide Skipping of Multiple Exons of the Spinal Muscular Atrophy Gene

Humans carry two nearly identical copies of Survival Motor Neuron gene: SMN1 and SMN2. Loss of SMN1 leads to spinal muscular atrophy (SMA), the most frequent genetic cause of infant mortality. While SMN2 cannot compensate for the loss of SMN1 due to predominant skipping of exon 7, correction of SMN2 exon 7 splicing holds the promise of a cure for SMA. Previously, we used cell-based models coupled with a multi-exon-skipping detection assay (MESDA) to demonstrate the vulnerability of SMN2 exons to aberrant splicing under the conditions of oxidative stress (OS). Here we employ a transgenic mouse model and MESDA to examine the OS-induced splicing regulation of SMN2 exons. We induced OS using paraquat that is known to trigger production of reactive oxygen species and cause mitochondrial dysfunction. We show an overwhelming co-skipping of SMN2 exon 5 and exon 7 under OS in all tissues except testis. We also show that OS increases skipping of SMN2 exon 3 in all tissues except testis. We uncover several new SMN2 splice isoforms expressed at elevated levels under the conditions of OS. We analyze cis-elements and transacting factors to demonstrate the diversity of mechanisms for splicing misregulation under OS. Our results of proteome analysis reveal downregulation of hnRNP H as one of the potential consequences of OS in brain. Our findings suggest SMN2 as a sensor of OS with implications to SMA and other diseases impacted by low levels of SMN protein

Possible Clues for Brain Energy Translation via Endolysosomal Trafficking of APP-CTFs in Alzheimer’s Disease

Vascular dysfunctions, hypometabolism, and insulin resistance are high and early risk factors for Alzheimer’s disease (AD), a leading neurological disease associated with memory decline and cognitive dysfunctions. Early defects in glucose transporters and glycolysis occur during the course of AD progression. Hypometabolism begins well before the onset of early AD symptoms; this timing implicates the vulnerability of hypometabolic brain regions to beta-secretase 1 (BACE-1) upregulation, oxidative stress, inflammation, synaptic failure, and cell death. Despite the fact that ketone bodies, astrocyte-neuron lactate shuttle, pentose phosphate pathway (PPP), and glycogenolysis compensate to provide energy to the starving AD brain, a considerable energy crisis still persists and increases during disease progression. Studies that track brain energy metabolism in humans, animal models of AD, and in vitro studies reveal striking upregulation of beta-amyloid precursor protein (β-APP) and carboxy-terminal fragments (CTFs). Currently, the precise role of CTFs is unclear, but evidence supports increased endosomal-lysosomal trafficking of β-APP and CTFs through autophagy through a vague mechanism. While intracellular accumulation of Aβ is attributed as both the cause and consequence of a defective endolysosomal-autophagic system, much remains to be explored about the other β-APP cleavage products. Many recent works report altered amino acid catabolism and expression of several urea cycle enzymes in AD brains, but the precise cause for this dysregulation is not fully explained. In this paper, we try to connect the role of CTFs in the energy translation process in AD brain based on recent findings

Possible Clues for Brain Energy Translation via Endolysosomal Trafficking of APP-CTFs in Alzheimer’s Disease

Vascular dysfunctions, hypometabolism, and insulin resistance are high and early risk factors for Alzheimer’s disease (AD), a leading neurological disease associated with memory decline and cognitive dysfunctions. Early defects in glucose transporters and glycolysis occur during the course of AD progression. Hypometabolism begins well before the onset of early AD symptoms; this timing implicates the vulnerability of hypometabolic brain regions to beta-secretase 1 (BACE-1) upregulation, oxidative stress, inflammation, synaptic failure, and cell death. Despite the fact that ketone bodies, astrocyte-neuron lactate shuttle, pentose phosphate pathway (PPP), and glycogenolysis compensate to provide energy to the starving AD brain, a considerable energy crisis still persists and increases during disease progression. Studies that track brain energy metabolism in humans, animal models of AD, and in vitro studies reveal striking upregulation of beta-amyloid precursor protein (β-APP) and carboxy-terminal fragments (CTFs). Currently, the precise role of CTFs is unclear, but evidence supports increased endosomal-lysosomal trafficking of β-APP and CTFs through autophagy through a vague mechanism. While intracellular accumulation of Aβ is attributed as both the cause and consequence of a defective endolysosomal-autophagic system, much remains to be explored about the other β-APP cleavage products. Many recent works report altered amino acid catabolism and expression of several urea cycle enzymes in AD brains, but the precise cause for this dysregulation is not fully explained. In this paper, we try to connect the role of CTFs in the energy translation process in AD brain based on recent findings

Antisense oligonucleotide mediated therapy of spinal muscular atrophy

Spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality. SMA results from deletions or mutations of survival motor neuron 1 (SMN1), an essential gene. SMN2, a nearly identical copy, can compensate for SMN1 loss if SMN2 exon 7 skipping is prevented. Among the many cis-elements involved in the splicing regulation of SMN exon 7, intronic splicing silencer N1 (ISS-N1) has emerged as the most effective target for an antisense oligonucleotide (ASO)-mediated splicing correction of SMN2 exon 7. Blocking of ISS-N1 by an ASO has been shown to fully restore SMN2 exon 7 inclusion in SMA patient cells as well as in vivo. Here we review how ISS-N1 targeting ASOs that use different chemistries respond differently in the various SMA mouse models. We also compare other ASO-based strategies for therapeutic splicing correction in SMA. Given that substantial progress on ASO-based strategies to promote SMN2 exon 7 inclusion in SMA has been made, and that similar approaches in a growing number of genetic diseases are possible, this report has wide implications.This is a post-print of an article from Translational Neuroscience 4, no. 1 (2013): 1–7, doi:10.2478/s13380-013-0109-2. The original publication is available at www.springerlink.com.</p