Sodium Phenylbutyrate Controls Neuroinflammatory and Antioxidant Activities and Protects Dopaminergic Neurons in Mouse Models of Parkinson’s Disease

Neuroinflammation and oxidative stress underlie the pathogenesis of various neurodegenerative disorders. Here we demonstrate that sodium phenylbutyrate (NaPB), an FDA-approved therapy for reducing plasma ammonia and glutamine in urea cycle disorders, can suppress both proinflammatory molecules and reactive oxygen species (ROS) in activated glial cells. Interestingly, NaPB also decreased the level of cholesterol but involved only intermediates, not the end product of cholesterol biosynthesis pathway for these functions. While inhibitors of both geranylgeranyl transferase (GGTI) and farnesyl transferase (FTI) inhibited the activation of NF-κB, inhibitor of GGTI, but not FTI, suppressed the production of ROS. Accordingly, a dominant-negative mutant of p21rac, but not p21ras, attenuated the production of ROS from activated microglia. Inhibition of both p21ras and p21rac activation by NaPB in microglial cells suggests that NaPB exerts anti-inflammatory and antioxidative effects via inhibition of these small G proteins. Consistently, we found activation of both p21ras and p21rac in vivo in the substantia nigra of acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson’s disease. Oral administration of NaPB reduced nigral activation of p21ras and p21rac, protected nigral reduced glutathione, attenuated nigral activation of NF-κB, inhibited nigral expression of proinflammatory molecules, and suppressed nigral activation of glial cells. These findings paralleled dopaminergic neuronal protection, normalized striatal neurotransmitters, and improved motor functions in MPTP-intoxicated mice. Consistently, FTI and GGTI also protected nigrostriata in MPTP-intoxicated mice. Furthermore, NaPB also halted the disease progression in a chronic MPTP mouse model. These results identify novel mode of action of NaPB and suggest that NaPB may be of therapeutic benefit for neurodegenerative disorders

Correction: A Physically-Modified Saline Suppresses Neuronal Apoptosis, Attenuates Tau Phosphorylation and Protects Memory in an Animal Model of Alzheimer's Disease

<p>Correction: A Physically-Modified Saline Suppresses Neuronal Apoptosis, Attenuates Tau Phosphorylation and Protects Memory in an Animal Model of Alzheimer's Disease</p

RNS60 inhibits Aβ-induced phosphorylation of Tau in SHSY5Y neuronal cells via PI3K – Akt pathway.

<p><i>A</i>, Cells preincubated with 10% RNS60 and NS for 1 h were stimulated by Aβ. After 3 h of challenge, cell lysates were analyzed by Western blotting with antibodies against phospho-Tau and Tau. <i>B</i>, Bands were scanned and results presented as protein expression relative to Tau. Results are expressed as mean ± SD of three independent experiments. <i>^ap<0.001 vs control; ^bp<0.001 vs Aβ</i>. <i>C</i>, RNS60-mediated prevention of Aβ-induced tau phosphorylation was also blocked by LY in SHSY5Y cells as monitored by immunoblotting under similar experimental set up. <i>D</i>, Phosphorylated Tau was quantified as densitometry values, which were normalized to Tau. Results are mean ± S.D. of three different experiments. <i>^ap<0.001 vs Control; ^bp<0.001 vs Aβ; ^cp<0.001 vs (Aβ+RNS60)</i>. <i>E</i>, RNS60-mediated prevention of Aβ-induced tau phosphorylation was also blocked by Akti in SHSY5Y cells. <i>F</i>, Phosphorylated Tau was quantified as densitometry values, which were normalized to Tau. Results are mean ± S.D. of three different experiments. <i>^ap<0.001 vs Control; ^bp<0.001 vs Aβ; ^cp<0.001 vs (Aβ+RNS60)</i>.</p

RNS60 treatment inhibits neuronal apoptosis <i>in vivo</i> in the hippocampus of Tg5XFAD mice.

<p>Tg mice (5 months old) were treated with RNS60 and NS (300 µl/mouse/2d) via i.p. injection and after 2 months of treatment, hippocampal sections were double-labeled for TUNEL and NeuN (A). Results represent analysis of two hippocampal sections of each of five mice per group. Tissue lysates were analyzed for cleaved caspase 3 (B&C), phospho-BAD (D&E) and phospho-Akt/total Akt (F&G) by Western blot. Bands were scanned and results presented as relative density (C, E & G). Results represent mean ± SEM of four mice per group. <i>^ap<0.001 vs non-Tg; ^bp<0.001 vs Tg</i>.</p

RNS60 treatment reduces the burden of amyloid beta from the hippocampus of Tg 5XFAD mice.

<p>Tg mice (5 months old) were treated with RNS60 and NS (300 µl/mouse/2d) via i.p. injection and after 2 months of treatment, hippocampal sections were immunolabeled with 82E1 antibody (A). Hippocampal homogenates were also analyzed for protein levels of Aβ by Western blot (B). Arrow indicates 4 kDa Aβ band. Bands were scanned and results presented as relative to control (non-Tg) (C). Results represent mean ± SEM of four mice per group. <i>^ap<0.001 vs non-Tg; ^bp<0.001 vs Tg</i>.</p

RNS60 treatment attenuates phosphorylation of tau in the hippocampus of Tg 5XFAD mice.

<p>Tg mice (5 months old) were treated with RNS60 and NS (300 µl/mouse/2d) via i.p. injection and after 2 months of treatment, phospho-tau (A) and total tau (B) were monitored in the hippocampus by immunofluorescence. Results represent analysis of two hippocampal sections of each of five mice per group. C, Tissue lysates were analyzed for phospho-tau and total tau by Western blot. <i>D</i>, Bands were scanned and results presented as ratio of phospho-tau to total tau. Results represent mean ± SEM of four mice per group. <i>^ap<0.001 vs non-Tg; ^bp<0.001 vs Tg</i>.</p