withanolides and Amyotrophic-Lateral-Sclerosis

Topics: Amyotrophic Lateral Sclerosis; Frontotemporal Dementia; Humans; Syndrome; Withanolides

Approximately 20% of cases of familial amyotrophic lateral sclerosis (ALS) are caused by mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1). Recent studies have shown that Withaferin A (WA), an inhibitor of nuclear factor-kappa B activity, was efficient in reducing disease phenotype in a TAR DNA binding protein 43 transgenic mouse model of ALS. These findings led us to test WA in mice from 2 transgenic lines expressing different ALS-linked SOD1 mutations, SOD1(G93A) and SOD1(G37R). Intraperitoneal administration of WA at a dosage of 4 mg/kg of body weight was initiated from postnatal day 40 until end stage in SOD1(G93A) mice, and from 9 months until end stage in SOD1(G37R) mice. The beneficial effects of WA in the SOD1(G93A) mice model were accompanied by an alleviation of neuroinflammation, a decrease in levels of misfolded SOD1 species in the spinal cord, and a reduction in loss of motor neurons resulting in delayed disease progression and mortality. Interestingly, WA treatment triggered robust induction of heat shock protein 25 (a mouse ortholog of heat shock protein 27), which may explain the reduced level of misfolded SOD1 species in the spinal cord of SOD1(G93A) mice and the decrease of neuronal injury responses, as revealed by real-time imaging of biophotonic SOD1(G93A) mice expressing a luciferase transgene under the control of the growth-associated protein 43 promoter. These results suggest that WA may represent a potential lead compound for drug development aiming to treat ALS.

Topics: Amyotrophic Lateral Sclerosis; Animals; Blotting, Western; Disease Models, Animal; Fluorescent Antibody Technique; Immunoprecipitation; Longevity; Mice; Mice, Transgenic; Motor Neurons; Neuroprotective Agents; Superoxide Dismutase; Superoxide Dismutase-1; Withanolides

Mutations in more than 10 genes are reported to cause familial amyotrophic lateral sclerosis (ALS). Among these genes, optineurin (OPTN) is virtually the only gene that is considered to cause classical ALS by a loss-of-function mutation. Wild-type optineurin (OPTN(WT) ) suppresses nuclear factor-kappa B (NF-κB) activity, but the ALS-causing mutant OPTN is unable to suppress NF-κB activity. Therefore, we knocked down OPTN in neuronal cells and examined the resulting NF-κB activity and phenotype. First, we confirmed the loss of the endogenous OPTN expression after siRNA treatment and found that NF-κB activity was increased in OPTN-knockdown cells. Next, we found that OPTN knockdown caused neuronal cell death. Then, overexpression of OPTN(WT) or OPTN(E) (50K) with intact NF-κB-suppressive activity, but not overexpression of ALS-related OPTN mutants, suppressed the neuronal death induced by OPTN knockdown. This neuronal cell death was inhibited by withaferin A, which selectively inhibits NF-κB activation. Lastly, involvement of the mitochondrial proapoptotic pathway was suggested for neuronal death induced by OPTN knockdown. Taken together, these results indicate that inappropriate NF-κB activation is the pathogenic mechanism underlying OPTN mutation-related ALS. Among the genes for typical amyotrophic lateral sclerosis (ALS) phenotypes, optineurin (OPTN) is virtually the only gene in which a loss-of-function mutation is considered as the principal disease mechanism. We found that OPTN knockdown induced neuronal cell death via NF-κB activation. Furthermore, proapoptotic molecules such as p53 and Bax representing downstream targets of NF-κB are suggested to be involved in neuronal death.

Topics: Amyotrophic Lateral Sclerosis; Animals; Antineoplastic Agents, Phytogenic; Blotting, Western; Cell Count; Cell Cycle Proteins; Cell Death; Cells, Cultured; Coloring Agents; Eye Proteins; Genes, p53; Genes, Reporter; Luciferases; Membrane Transport Proteins; Mice; Mutation; Neurons; NF-kappa B; Plasmids; Real-Time Polymerase Chain Reaction; RNA, Small Interfering; Signal Transduction; Transfection; Trypan Blue; Tumor Necrosis Factor-alpha; Withanolides

TDP-43 (TAR DNA-binding protein 43) inclusions are a hallmark of amyotrophic lateral sclerosis (ALS). In this study, we report that TDP-43 and nuclear factor κB (NF-κB) p65 messenger RNA and protein expression is higher in spinal cords in ALS patients than healthy individuals. TDP-43 interacts with and colocalizes with p65 in glial and neuronal cells from ALS patients and mice expressing wild-type and mutant TDP-43 transgenes but not in cells from healthy individuals or nontransgenic mice. TDP-43 acted as a co-activator of p65, and glial cells expressing higher amounts of TDP-43 produced more proinflammatory cytokines and neurotoxic mediators after stimulation with lipopolysaccharide or reactive oxygen species. TDP-43 overexpression in neurons also increased their vulnerability to toxic mediators. Treatment of TDP-43 mice with Withaferin A, an inhibitor of NF-κB activity, reduced denervation in the neuromuscular junction and ALS disease symptoms. We propose that TDP-43 deregulation contributes to ALS pathogenesis in part by enhancing NF-κB activation and that NF-κB may constitute a therapeutic target for the disease.

Topics: Amyotrophic Lateral Sclerosis; Analysis of Variance; Animals; Blotting, Western; DNA Primers; DNA-Binding Proteins; Electrophoretic Mobility Shift Assay; Enzyme-Linked Immunosorbent Assay; Humans; Immunoprecipitation; Mass Spectrometry; Mice; Mice, Transgenic; Microscopy, Fluorescence; Neuroglia; Neuromuscular Junction; Neurons; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Signal Transduction; Spinal Cord; Transcription Factor RelA; Transgenes; Withanolides