Sodium benzoate, a food additive and a metabolite of cinnamon, modifies T cells at multiple steps and inhibits adoptive transfer of experimental allergic encephalomyelitis

Muscle-building supplement β-hydroxy β-methylbutyrate stimulates the maturation of oligodendroglial progenitor cells to oligodendrocytes

Oligodendrocytes are the myelinating cells in the CNS and multiple sclerosis (MS) is a demyelinating disorder that is characterized by progressive loss of myelin. Although oligodendroglial progenitor cells (OPCs) should be differentiated into oligodendrocytes, for multiple reasons, OPCs fail to differentiate into oligodendrocytes in MS. Therefore, increasing the maturation of OPCs to oligodendrocytes may be of therapeutic benefit for MS. The β-hydroxy β-methylbutyrate (HMB) is a muscle-building supplement in humans and this study underlines the importance of HMB in stimulating the maturation of OPCs to oligodendrocytes. HMB treatment upregulated the expression of different maturation markers including PLP, MBP, and MOG in cultured OPCs. Double-label immunofluorescence followed by immunoblot analyses confirmed the upregulation of OPC maturation by HMB. While investigating mechanisms, we found that HMB increased the maturation of OPCs isolated from peroxisome proliferator-activated receptor β-/- (PPARβ-/-) mice, but not PPARα-/- mice. Similarly, GW6471 (an antagonist of PPARα), but not GSK0660 (an antagonist of PPARβ), inhibited HMB-induced maturation of OPCs. GW9662, a specific inhibitor of PPARγ, also could not inhibit HMB-mediated stimulation of OPC maturation. Furthermore, PPARα agonist GW7647, but neither PPARβ agonist GW0742 nor PPARγ agonist GW1929, alone increased the maturation of OPCs. Finally, HMB treatment of OPCs led to the recruitment of PPARα, but neither PPARβ nor PPARγ, to the PLP gene promoter. These results suggest that HMB stimulates the maturation of OPCs via PPARα and that HMB may have therapeutic prospects in remyelination.

Amelioration of experimental autoimmune encephalomyelitis by gemfibrozil in mice via PPARβ/δ: implications for multiple sclerosis

It is important to describe effective and non-toxic therapies for multiple sclerosis (MS), an autoimmune demyelinating disease. Experimental autoimmune encephalomyelitis (EAE) is an immune-mediated inflammatory disease that serves as a model for MS. Earlier we and others have shown that, gemfibrozil, a lipid-lowering drug, exhibits therapeutic efficacy in EAE. However, the underlying mechanism was poorly understood. Although gemfibrozil is a known ligand of peroxisome proliferator-activated receptor α (PPARα), here, we established that oral administration of gemfibrozil preserved the integrity of blood-brain barrier (BBB) and blood-spinal cord barrier (BSB), decreased the infiltration of mononuclear cells into the CNS and inhibited the disease process of EAE in both wild type and PPARα-/- mice. On the other hand, oral gemfibrozil was found ineffective in maintaining the integrity of BBB/BSB, suppressing inflammatory infiltration and reducing the disease process of EAE in mice lacking PPARβ (formerly PPARδ), indicating an important role of PPARβ/δ, but not PPARα, in gemfibrozil-mediated preservation of BBB/BSB and protection of EAE. Regulatory T cells (Tregs) play a critical role in the disease process of EAE/MS and we also demonstrated that oral gemfibrozil protected Tregs in WT and PPARα-/- EAE mice, but not PPARβ-/- EAE mice. Taken together, our findings suggest that gemfibrozil, a known ligand of PPARα, preserves the integrity of BBB/BSB, enriches Tregs, and inhibits the disease process of EAE via PPARβ, but not PPARα.

Induction of IL-2 by interleukin-12 p40 homodimer and IL-12, but not IL-23, in microglia and macrophages: Implications for multiple sclerosis

The level of IL-2 increases markedly in serum and central nervous system (CNS) of patients with multiple sclerosis (MS) and animals with experimental allergic encephalomyelitis (EAE). However, mechanisms by which IL-2 is induced under autoimmune demyelinating conditions are poorly understood. The present study underlines the importance of IL-12p40 homodimer (p402), the so-called biologically inactive molecule, in inducing the expression of IL-2 in mouse BV-2 microglial cells, primary mouse and human microglia, mouse peritoneal macrophages, RAW264.7 macrophages, and T cells. Interestingly, we found that p402 and IL-12p70 (IL-12), but not IL-23, dose-dependently induced the production of IL-2 and the expression of IL-2 mRNA in microglial cells. Similarly, p402 also induced the activation of IL-2 promoter in microglial cells and RAW264.7 cells. Among various stimuli tested, p402 was the most potent stimulus followed by IFN-γ, bacterial lipopolysaccharide, HIV-1 gp120, and IL-12 in inducing the activation of IL-2 promoter in microglial cells. Moreover, p402, but not IL-23, increased NFATc2 mRNA expression and the transcriptional activity of NFAT. Furthermore, induction of IL-2 mRNA expression by over-expression of p40, but not by p19, cDNA indicated that p40, but not p19, is responsible for the induction of IL-2 mRNA in microglia. Finally, by using primary microglia from IL to 12 receptor β1 deficient (IL-12Rβ1-/-) and IL-12 receptor β2 deficient (IL-12Rβ2-/-) mice, we demonstrate that p402 induces the expression of IL-2 via IL-12Rβ1, but not IL-12Rβ2. In experimental autoimmune encephalomyelitis, an animal model of MS, neutralization of p402 by mAb a3-1d led to decrease in clinical symptoms and reduction in IL-2 in T cells and microglia. These results delineate a new biological function of p402, which is missing in the so-called autoimmune cytokine IL-23, and raise the possibility of controlling increased IL-2 and the disease process of MS via neutralization of p402.

Suppression of Experimental Autoimmune Encephalomyelitis in Mice by β-Hydroxy β-Methylbutyrate, a Body-Building Supplement in Humans

Although several immunomodulatory drugs are available for multiple sclerosis (MS), most present significant side effects with long-term use. Therefore, delineation of nontoxic drugs for MS is an important area of research. β-Hydroxy β-methylbutyrate (HMB) is accessible in local GNC stores as a muscle-building supplement in humans. This study underlines the importance of HMB in suppressing clinical symptoms of experimental autoimmune encephalomyelitis (EAE) in mice, an animal model of MS. Dose-dependent study shows that oral HMB at a dose of 1 mg/kg body weight/d or higher significantly suppresses clinical symptoms of EAE in mice. Accordingly, orally administered HMB attenuated perivascular cuffing, preserved the integrity of the blood-brain barrier and blood-spinal cord barrier, inhibited inflammation, maintained the expression of myelin genes, and blocked demyelination in the spinal cord of EAE mice. From the immunomodulatory side, HMB protected regulatory T cells and suppressed Th1 and Th17 biasness. Using peroxisome proliferator-activated receptor (PPAR)α-/- and PPARβ-/- mice, we observed that HMB required PPARβ, but not PPARα, to exhibit immunomodulation and suppress EAE. Interestingly, HMB reduced the production of NO via PPARβ to protect regulatory T cells. These results describe a novel anti-autoimmune property of HMB that may be beneficial in the treatment of MS and other autoimmune disorders.

Toll-like receptors and nuclear factor kappa B signaling pathway involvement in hepatorenal oxidative damage induced by some food preservatives in rats

Chemical food preservatives are extensively found in various processed food products in the human environment. Hence, this study aimed to investigate the effect of long-term exposure to five food preservatives (potassium sorbate (PS), butylated hydroxyanisole (BHA), sodium benzoate (SB), calcium propionate (CP), and boric acid (BA)) on the liver and kidney in rats and the probable underlying mechanisms. For 90 days, sixty male albino rats were orally given either water (control), 0.09 mg/kg b.wt BHA, 4.5 mg/kg b.wt PS, 0.9 mg/kg b.wt SB, 0.16 mg/kg b.wt BA, or 0.18 mg/kg b.wt CP. Liver and kidney function tests were assessed. Hepatic and renal oxidative stress biomarkers were estimated. Histologic examination analysis of liver and kidney tissues was achieved. Toll-like receptors 2 and 4 (TLR-2 and TLR-4), tumor necrosis factor-alpha (TNF-α), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) mRNA expression levels were measured. The results revealed that long-term oral dosing of the five food preservatives resulted in significant increases in alkaline phosphatase, alanine transaminase, aspartate transaminase, urea, uric acid, and creatinine levels. There were significant reductions in hepatic and renal antioxidant enzymes, an increase in MDA concentrations, and pathological alterations in renal and hepatic tissues. The mRNA levels of TLR-4, TLR-2, NF-κB, and TNF-α were elevated in the food preservatives-exposed groups. Conclusively, the current findings revealed that long-term exposure to PS, BHA, SB, CP, and BA has a negative impact on liver and kidney function. Furthermore, these negative effects could be mediated via oxidative stress induction, inflammatory reactions, and cytokine production.

Sodium benzoate attenuates 2,8-dihydroxyadenine nephropathy by inhibiting monocyte/macrophage TNF-α expression

Sodium benzoate (SB), a known D-amino acid oxidase (DAO) enzyme inhibitor, has an anti-inflammatory effect, although its role in renal damage has not been explored. 2,8-dihydroxyadenine crystal induced chronic kidney disease, in which TNF-α is involved in the pathogenesis, was established by oral adenine administration in C57BL/6JJcl mice (AdCKD) with or without SB to investigate its renal protective effects. SB significantly attenuated AdCKD by decreasing serum creatinine and urea nitrogen levels, and kidney interstitial fibrosis and tubular atrophy scores. The survival of AdCKD mice improved 2.6-fold by SB administration. SB significantly decreased the number of infiltrating macrophages observed in the positive F4/80 immunohistochemistry area and reduced the expression of macrophage markers and inflammatory genes, including TNF-α, in the kidneys of AdCKD. Human THP-1 cells stimulated with either lipopolysaccharide or TNF-α showed increased expression of inflammatory genes, although this was significantly reduced by SB, confirming the anti-inflammatory effects of SB. SB exhibited renal protective effects in AdCKD in DAO enzyme deficient mice, suggesting that anti-inflammatory effect of SB was independent of DAO enzyme activity. Moreover, binding to motif DNA sequence, protein level, and mRNA level of NF-κB RelB were significantly inhibited by SB in AdCKD kidneys and lipopolysaccharide treated THP-1 cells, respectively. We report that anti-inflammatory property of SB is independent of DAO enzymatic activity and is associated with down regulated NF-κB RelB as well as its downstream inflammatory genes such as TNF-α in AdCKD.

Regression of Lung Cancer in Mice by Intranasal Administration of SARS-CoV-2 Spike S1

This study underlines the importance of SARS-CoV-2 spike S1 in prompting death in cultured non-small cell lung cancer (NSCLC) cells and in vivo in lung tumors in mice. Interestingly, we found that recombinant spike S1 treatment at very low doses led to death of human A549 NSCLC cells. On the other hand, boiled recombinant SARS-CoV-2 spike S1 remained unable to induce death, suggesting that the induction of cell death in A549 cells was due to native SARS-CoV-2 spike S1 protein. SARS-CoV-2 spike S1-induced A549 cell death was also inhibited by neutralizing antibodies against spike S1 and ACE2. Moreover, our newly designed wild type ACE2-interacting domain of SARS-CoV-2 (wtAIDS), but not mAIDS, peptide also attenuated SARS-CoV-2 spike S1-induced cell death, suggesting that SARS-CoV-2 spike S1-induced death in A549 NSCLC cells depends on its interaction with ACE2 receptor. Similarly, recombinant spike S1 treatment also led to death of human H1299 and H358 NSCLC cells. Finally, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) intoxication led to the formation tumors in lungs of A/J mice and alternate day intranasal treatment with low dose of recombinant SARS-CoV-2 spike S1 from 22-weeks of NNK insult (late stage) induced apoptosis and tumor regression in the lungs. These studies indicate that SARS-CoV-2 spike S1 may have implications for lung cancer treatment.

Sodium Benzoate—Harmfulness and Potential Use in Therapies for Disorders Related to the Nervous System: A Review

Currently, due to the large number of reports regarding the harmfulness of food additives, more and more consumers follow the so-called “clean label” trend, i.e., prefer and choose the least-processed food products. One of the compounds known as a preservative with a high safety profile is sodium benzoate. While some studies show that it can be used to treat conditions such as depression, pain, schizophrenia, autism spectrum disorders, and neurodegenerative diseases, others report its harmfulness. For example, it was found to cause mutagenic effects, generate oxidative stress, disrupt hormones, and reduce fertility. Due to such disparate results, the purpose of this study is to comprehensively discuss the safety profile of sodium benzoate and its potential use in neurodegenerative diseases, especially in autism spectrum disorder (ASD), schizophrenia, major depressive disorder (MDD), and pain relief.

Sodium Benzoate, a Metabolite of Cinnamon and a Food Additive, Improves Cognitive Functions in Mice after Controlled Cortical Impact Injury

Traumatic brain injury (TBI) is a major health concern, sometimes leading to long-term neurological disability, especially in children, young adults and war veterans. Although research investigators and clinicians have applied different treatment strategies or neurosurgical procedures to solve this health issue, we are still in need of an effective therapy to halt the pathogenesis of brain injury. Earlier, we reported that sodium benzoate (NaB), a metabolite of cinnamon and a Food and Drug Administration-approved drug against urea cycle disorders and glycine encephalopathy, protects neurons in animal models of Parkinson's disease and Alzheimer's disease. This study was undertaken to examine the therapeutic efficacy of NaB in a controlled cortical impact (CCI)-induced preclinical mouse model of TBI. Oral treatment with NaB, but not sodium formate (NaFO), was found to decrease the activation of microglia and astrocytes and to inhibit the expression of inducible nitric oxide synthase (iNOS) in the hippocampus and cortex of CCI-insulted mice. Further, administration of NaB also reduced the vascular damage and decreased the size of the lesion cavity in the brain of CCI-induced mice. Importantly, NaB-treated mice showed significant improvements in memory and locomotor functions as well as displaying a substantial reduction in depression-like behaviors. These results delineate a novel neuroprotective property of NaB, highlighting its possible therapeutic importance in TBI.

Glyceryl tribenzoate: A food additive with unique properties to be a substitute for cinnamon

Cinnamon is a regularly used natural seasoning and flavoring material throughout the world for eras. Recent laboratory studies have demonstrated that oral cinnamon may be beneficial for different neuroinflammatory and neurodegenerative disorders such as multiple sclerosis (MS), Parkinson's disease (PD), Alzheimer's disease (AD), and Lewy body diseases (LBD). However, cinnamon's certain limitations (e.g. unavailability of true Ceylon cinnamon throughout the world, impurities in ground cinnamon, etc.) have initiated an interest among researchers to find an alternate of cinnamon that can potentially deliver the same efficacy in the diseases mentioned above. Glyceryl tribenzoate (GTB) is a U.S. Food and Drug Administration (FDA)-approved flavoring ingredient that is used in food and food packaging industries. It has been found that similar to cinnamon, oral GTB is capable of upregulating regulatory T cells and suppressing the autoimmune disease process of experimental autoimmune encephalomyelitis, an animal model of MS. Moreover, both GTB and cinnamon metabolite sodium benzoate (NaB) have the potency to attenuate neurodegenerative pathology in a mouse model of Huntington disease (HD). Here, we have also demonstrated anti-inflammatory property of GTB in astrocytes and macrophages, a property that is also seen with cinnamon and its metabolite sodium benzoate (NaB). Therefore, here, we have made a sincere attempt to discuss the similarities and dissimilarities between cinnamon and GTB with a focus whether GTB has the potential to be considered as a substitute of cinnamon for neuroinflammatory and neurodegenerative disorders.

Activation of PPARα enhances astroglial uptake and degradation of β-amyloid

[Figure: see text].

Reduction of Lewy Body Pathology by Oral Cinnamon

α-Synucleinopathies in a broader sense comprise of several neurodegenerative disorders that primarily include Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). These disorders are well characterized by the accumulation of aggregated insoluble α-synuclein (α-syn) protein known as Lewy bodies. Till date no effective cure is available to reduce the burden of Lewy body. The present investigation underlines the importance of a naturally used spice and flavoring agent viz. cinnamon in reducing α-syn deposits in transgenic mice expressing mutant A53T human α-syn. Upon oral administration, cinnamon markedly reduced the level of insoluble α-syn in nigra, hippocampus and brain stem of A53T mice. We also demonstrated that sodium benzoate (NaB), a metabolite of cinnamon, a widely used food additive and a FDA-approved drug for glycine encephalopathy, was also capable of reducing α-syn deposits in A53T mice. In addition, both cinnamon and NaB treatments showed improvement in their motor and cognitive functions. Glial activation plays an important role in the pathogenesis of various neurodegenerative disorders including PD, DLB and MSA, and we found suppression of microglial and astroglial activation in the nigra of A53T mice upon cinnamon treatment. Moreover, neuroprotective proteins like DJ-1 and Parkin are known to reduce the formation of Lewy bodies in the CNS. Accordingly, we observed upregulation and/or normalization of DJ-1 and Parkin in the nigra of A53T mice by treatment with cinnamon and NaB. Together, these results highlight a new therapeutic property of cinnamon and suggest that cinnamon and NaB may be used to halt the progression of α-synucleinopathies.Graphical Abstract.

Stimulation of Dopamine Production by Sodium Benzoate, a Metabolite of Cinnamon and a Food Additive

BACKGROUND

Parkinson's disease (PD) is one of the most important neurodegenerative disorders in human in which recovery of functions could be achieved by improving the survival and function of residual dopaminergic neurons in the substantia nigra pars compacta. Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the dopamine (DA) biosynthesis pathway.

OBJECTIVE

Earlier our laboratory has shown that sodium benzoate (NaB), a metabolite of cinnamon and an FDA-approved drug against urea cycle disorders and glycine encephalopathy, increases neuroprotective molecules and protects dopaminergic neurons in a mouse model of PD. Here, we examined whether NaB could stimulate the production of DA in dopaminergic neurons.

METHODS

We employed PCR, real-time PCR, western blot, immunostaining, and HPLC to study the signature function of dopaminergic neurons. Locomotor functions were monitored in mice by open-field.

RESULTS

NaB increased the mRNA and protein expression of TH to produce DA in mouse MN9D dopaminergic neuronal cells. Accordingly, oral feeding of NaB increased the expression of TH in the nigra, upregulated striatal DA, and improved locomotor activities in striatum of normal C57/BL6 and aged A53T-α-syn transgenic mice. Rapid induction of cAMP response element binding (CREB) activation by NaB in dopaminergic neuronal cells and the abrogation of NaB-induced expression of TH by siRNA knockdown of CREB suggest that NaB stimulates the transcription of TH in dopaminergic neurons via CREB.

CONCLUSION

These results indicate a new function of NaB in which it may be beneficial in PD via stimulation of DA production from residual dopaminergic neurons.

Alleviation of Huntington pathology in mice by oral administration of food additive glyceryl tribenzoate

Huntington's disease (HD) is a neurodegenerative disorder characterized by accumulation of mutant huntingtin protein and significant loss of neurons in striatum and cortex. Along with motor difficulties, the HD patients also manifest anxiety and loss of cognition. Unfortunately, the clinically approved drugs only offer symptomatic relief and are not free from side effects. This study underlines the importance of glyceryl tribenzoate (GTB), an FDA-approved food flavoring ingredient, in alleviating HD pathology in transgenic N171-82Q mouse model. Oral administration of GTB significantly reduced mutant huntingtin level in striatum, motor cortex as well as hippocampus and increased the integrity of viable neurons. Furthermore, we found the presence of sodium benzoate (NaB), a FDA-approved drug for urea cycle disorders and glycine encephalopathy, in the brain of GTB-fed HD mice. Accordingly, NaB administration also markedly decreased huntingtin level in striatum and cortex. Glial activation is found to coincide with neuronal death in affected regions of HD brains. Interestingly, both GTB and NaB treatment suppressed activation of glial cells and inflammation in the brain. Finally, neuroprotective effect of GTB and NaB resulted in improved motor performance of HD mice. Collectively, these results suggest that GTB and NaB may be repurposed for HD.

Neuroprotective potential of cinnamon and its metabolites in Parkinson's disease: Mechanistic insights, limitations, and novel therapeutic opportunities

Parkinson's disease (PD) is the most common neurodegenerative movement disorder with obscure etiology and no disease-modifying therapy to date. Hence, novel, safe, and low cost-effective approaches employing medicinal plants are currently receiving increased attention. A growing body of evidence has revealed that cinnamon, being widely used as a spice of unique flavor and aroma, may exert neuroprotective effects in several neurodegenerative diseases, including PD. In vitro evidence has indicated that the essential oils of Cinnamomum species, mainly cinnamaldehyde and sodium benzoate, may protect against oxidative stress-induced cell death, reactive oxygen species generation, and autophagy dysregulation, thus acting in a potentially neuroprotective manner. In vivo evidence has demonstrated that oral administration of cinnamon powder and sodium benzoate may protect against dopaminergic cell death, striatal neurotransmitter dysregulation, and motor deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse models of PD. The underlying mechanisms of its action include autophagy regulation, antioxidant effects, upregulation of Parkin, DJ-1, glial cell line-derived neurotrophic factor, as well as modulation of the Toll-like receptors/nuclear factor-κB pathway and inhibition of the excessive proinflammatory responses. In addition, in vitro and in vivo studies have shown that cinnamon extracts may affect the oligomerization process and aggregation of α-synuclein. Herein, we discuss recent evidence on the novel therapeutic opportunities of this phytochemical against PD, indicating additional mechanistic aspects that should be explored and potential obstacles/limitations that need to be overcome for its inclusion in experimental PD therapeutics.

Neuroprotective potential of cinnamon and its metabolites in Parkinson's disease: Mechanistic insights, limitations, and novel therapeutic opportunities

Parkinson's disease (PD) is the most common neurodegenerative movement disorder with obscure etiology and no disease-modifying therapy to date. Hence, novel, safe, and low cost-effective approaches employing medicinal plants are currently receiving increased attention. A growing body of evidence has revealed that cinnamon, being widely used as a spice of unique flavor and aroma, may exert neuroprotective effects in several neurodegenerative diseases, including PD. In vitro evidence has indicated that the essential oils of Cinnamomum species, mainly cinnamaldehyde and sodium benzoate may protect against oxidative stress-induced cell death, reactive oxygen species generation, and autophagy dysregulation, thus acting in a potentially neuroprotective manner. In vivo evidence has demonstrated that oral administration of cinnamon powder and sodium benzoate may protect against dopaminergic cell death, striatal neurotransmitter dysregulation, and motor deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse models of PD. The underlying mechanisms of its action include autophagy regulation, antioxidant effects, upregulation of Parkin, DJ-1, glial cell line-derived neurotrophic factor, as well as modulation of the TLR/NF-κB pathway and inhibition of the excessive proinflammatory responses. In addition, in vitro and in vivo studies have shown that cinnamon extracts may affect the oligomerization process and aggregation of α-synuclein. Herein, we discuss recent evidence on the novel therapeutic opportunities of this phytochemical against PD, indicating additional mechanistic aspects that should be explored, and potential obstacles/limitations that need to be overcome, for its inclusion in experimental PD therapeutics.

Can cinnamon spice down autoimmune diseases?

Autoimmune diseases are one of the dreadful group of human diseases that have always been of keen interest to researchers. Due to complex and broad-spectrum nature, scientists are not yet able to pinpoint the pathogenesis of and delineate effective therapy against this group of diseases. However, it is becoming clear that a decrease in number and function of T regulatory cells (Treg), an increase in autoreactive Th1/Th17 cells and associated immunomodulation and inflammation participate in the pathogenesis of many autoimmune diseases. Cinnamon (Cinnamonum verum or Cinnamonum cassia) is a widely used natural spice and flavoring ingredient and its metabolite sodium benzoate (NaB) is a food-additive and FDA-approved drug against nonketotic hyperglycinemia (NKH) and urea cycle disorders (UCD). Recent studies indicate that cinnamon either in powder or extract form and NaB are capable of modulating different autoimmune pathways as well as protecting animals from different autoimmune disorders. Here, we have made an honest attempt to delineate such pieces of evidence with available anti-autoimmune mechanisms and analyze whether cinnamon supplements could be used to control the fury of autoimmune disorders.

Intranasal Methylprednisolone Effectively Reduces Neuroinflammation in Mice With Experimental Autoimmune Encephalitis

Relapsing-remitting multiple sclerosis, the most common form, is characterized by acute neuroinflammatory episodes. In addition to continuous disease-modifying therapy, these relapses require treatment to prevent lesion accumulation and progression of disability. Intravenous methylprednisolone (1-2 g for 3-5 days) is the standard treatment for relapses. However, this treatment is invasive, requires hospitalization, leads to substantial systemic exposure of glucocorticoids, and can only reach modest concentrations in the central nervous system (CNS). Intranasal delivery may represent an alternative to deliver relapse treatment directly to the CNS with higher concentrations and reducing side effects. Histopathological analysis revealed that intranasal administration of methylprednisolone to mice with experimental autoimmune encephalomyelitis (EAE) suppressed the neuroinflammatory peak, and reduced immune cell infiltration and demyelination in the CNS similarly to intravenous administration. Treatment also downregulated Iba1 and GFAP expression. A similar significant reduction of IL-1β, IL-6, IL-17, IFN-γ, and TNF-α levels in the spinal cord was attained in both intranasal and intravenously treated mice. No damage in the nasal cavity was found after intranasal administration. This study demonstrates that intranasal delivery of methylprednisolone is as efficient as the intravenous route to treat neuroinflammation in EAE.

Exploring the therapeutic potential of sodium benzoate in acetic acid-induced ulcerative colitis in rats

Background Ulcerative colitis is a chronic mucosal inflammation of the large intestine mainly affecting the colon and rectum. The lack of effective and safe therapeutic agents led to the identification of new therapeutic agents to effectively manage the symptoms and complications of ulcerative colitis. The present study aimed to evaluate the protective effect of sodium benzoate in acetic acid-induced ulcerative colitis in rats. Methods Infusion of 3% acetic acid in the colon through the rectum was done to construct a rat model of ulcerative colitis. After 5 days of infusion, macroscopic, biochemical, and histopathological examinations and disease activity scoring of the colon were done to assess colonic damage. Results Acetic acid infusion resulted in severe inflammation in the colon assessed macroscopically and histopathologically. Moreover, it also led to increase in myeloperoxidase (MPO) and reduction in glutathione (GSH) levels. In the present study, repeated administration of sodium benzoate (400 and 800 mg/kg i.p.) and sulfasalazine (500 mg/kg orally) for 7 days, i.e. 2 days before and continued for 5 days after acetic acid infusion, significantly attenuated macroscopic damage and disease activity score as compared to disease control. Further, it also significantly reduced the levels of MPO and enhanced colonic levels of reduced GSH. However, the lower dose of sodium benzoate (200 mg/kg) did not show sufficient protective effect in acetic acid-induced ulcerative colitis. Further, sodium benzoate per se did not show any effect in normal rats. Conclusions The observed protective effect of sodium benzoate may be due to its antioxidant and anti-inflammatory activities in an ulcerative colitis model.

Aspirin up-regulates suppressor of cytokine signaling 3 in glial cells via PPARα

Neuroinflammation is being recognized as a hallmark of different neurodegenerative disorders, including Alzheimer's disease. Suppressor of cytokine signaling 3 (SOCS3) is an anti-inflammatory molecule, which is known to inhibit cytokine signaling and inflammatory gene expression in different cells. However, the pathways by which SOCS3 could be up-regulated in brain cells are poorly understood. Aspirin is a widely available pain reliever that is showing promise beyond its known pain-relieving capacity. This study underlines the importance of aspirin in upregulating SOCS3 in astrocytes and microglia. Aspirin increased the expression of Socs3 mRNA and protein in mouse astrocytes and BV-2 microglial cells in both a time- and dose-dependent manner. While investigating the mechanism, we found that Socs3 gene promoter harbors peroxisome proliferator response element and that aspirin up-regulated SOCS3 in astrocytes isolated from PPARβ (-/-), but not PPARα (-/-), mice. Accordingly, aspirin increased SOCS3 in vivo in the cortex of wild type and PPARβ (-/-), but not PPARα (-/-), mice. Similarly, aspirin treatment increased astroglial and microglial SOCS3 in the cortex of FAD5X, but not FAD5X/PPARα (-/-), mice. Finally, recruitment of PPARα by aspirin to the proximal, but not distal, peroxisome proliferator response element of the Socs3 promoter suggests that aspirin increases the transcription of Socs3 gene via PPARα. This study describes a novel property of aspirin in elevating SOCS3 in glial cells via PPARα and suggests that aspirin may be further considered for therapeutic application in neuroinflammatory and neurodegenerative disorders.

Upregulation of tripeptidyl-peptidase 1 by 3-hydroxy-(2,2)-dimethyl butyrate, a brain endogenous ligand of PPARα: Implications for late-infantile Batten disease therapy

The late-infantile Batten disease or late-infantile neuronal ceroid lipofuscinosis (LINCL) is an autosomal recessive lysosomal storage disorder caused by mutations in the Cln2 gene leading to deficiency of lysosomal enzyme tripeptidyl peptidase 1 (TPP1). At present, available options for this fatal disorder are enzyme replacement therapy and gene therapy, which are extensively invasive and expensive. Our study demonstrates that 3-hydroxy-(2,2)-dimethyl butyrate (HDMB), a brain endogenous molecule, is capable of stimulating TPP1 expression and activity in mouse primary astrocytes and a neuronal cell line. HDMB activated peroxisome proliferator-activated receptor-α (PPARα), which, by forming heterodimer with Retinoid X receptor-α (RXRα), transcriptionally upregulated the Cln2 gene. Moreover, by using primary astrocytes from wild type, PPARα-/- and PPARβ-/- mice, we demonstrated that HDMB specifically required PPARα for inducing TPP1 expression. Finally, oral administration of HDMB to Cln2 heterozygous (Cln2+/-) mice led to a marked upregulation of TPP1 expression in the motor cortex and striatum in a PPARα-dependent fashion. Our study suggests that HDMB, a brain endogenous ligand of PPARα, might have therapeutic importance for LINCL treatment.

Cinnamon and its Metabolite Protect the Nigrostriatum in a Mouse Model of Parkinson's Disease Via Astrocytic GDNF

Glial cell line-derived neurotrophic factor (GDNF) has potent neurotrophic effects and is known to promote the dopaminergic (DA) neuronal survival in cellular and animal models of Parkinson's disease (PD). However, long-term ectopic GDNF delivery is associated with long lasting adverse side effects in PD patients. Therefore, finding safer and effective ways to elevate endogenous GDNF levels is an active area of research. This study underlines the importance of sodium benzoate (NaB), a metabolite of commonly-used spice cinnamon, a food-additive and an FDA-approved drug against hyperammonemia, in stimulating GDNF in primary mouse and human astrocytes. Presence of cAMP response element (CRE) in the Gdnf gene promoter, recruitment of CREB to the Gdnf promoter by NaB and abrogation of NaB-mediated GDNF expression by siRNA knockdown of CREB suggest that NaB induces the transcription of Gdnf via CREB. Finally, oral administration of NaB and cinnamon itself increased the level of GDNF in vivo in the substantia nigra pars compacta (SNpc) of normal as well as MPTP-intoxicated mice. Accordingly, cinnamon and NaB treatment protected tyrosine hydroxylase positive neurons in the SNpc and fibers in the striatum, normalized striatal neurotransmitters, and improved locomotor activities in MPTP-intoxicated Gfap^cre mice, but not Gdnf^Δastro mice lacking GDNF in astrocytes. These findings highlight the importance of astroglial GDNF in cinnamon- and NaB-mediated protection of the nigrostriatum in MPTP mouse model of PD and suggest possible therapeutic potential of cinnamon and NaB in PD patients. Graphical abstract Cinnamon metabolite sodium benzoate (NaB) activates cAMP-response element-binding (CREB) via protein kinase A (PKA) in astrocytes. Activated CREB then binds to cAMP-response element (CRE) present in GDNF gene promoter to stimulate the transcription of GDNF in astrocytes. This astrocytic GDNF leads to nigral trophism and protects dopaminergic neurons from MPTP insult.

Natrium Benzoate Alleviates Neuronal Apoptosis via the DJ-1-Related Anti-oxidative Stress Pathway Involving Akt Phosphorylation in a Rat Model of Traumatic Spinal Cord Injury

This study aimed to explore the neuroprotective effects and mechanisms of natrium benzoate (NaB) and DJ-1 in attenuating reactive oxygen species (ROS)-induced neuronal apoptosis in traumatic spinal cord injury (t-SCI) in rats. T-SCI was induced by clip compression. The protein expression and neuronal apoptosis was evaluated by Western blotting, double immunofluorescence staining and transmission electron microscope (TEM). ROS level, spinal cord water content (SCWC) and Evans blue (EB) extravasation was also examined. Locomotor function was evaluated by Basso, Beattie, and Bresnahan (BBB) and inclined plane test (IPT) scores. We found that DJ-1 is expressed in spinal cord neurons and increased after t-SCI. At 24 h post-injury, the levels of DJ-1, p-Akt, SOD2, ROS, p-p38 MAPK/p38 MAPK ratio, and CC-3 increased, while the Bcl-2/Bax ratio decreased. NaB upregulated DJ-1, p-Akt, and SOD2, decreased ROS, p-p38 MAPK/p38 MAPK ratio, and CC-3, and increased the Bcl-2/Bax ratio, which were reversed by DJ-1 siRNA. The proportion of CC-3- and TUNEL-positive neurons also increased after t-SCI and was reduced by NaB. These effects were reversed by MK2206. Moreover, the level of oxDJ-1 increased after t-SCI, which was decreased by DJ-1 siRNA, NaB or the combination of them. NaB also reduced mitochondrial vacuolization, SCWC and EB extravasation, and improved locomotor function assessed by the BBB and IPT scores. In conclusion, NaB increased DJ-1, and thus reduced ROS and ROS-induced neuronal apoptosis by promoting Akt phosphorylation in t-SCI rats. NaB shows potential as a therapeutic agent for t-SCI, with DJ-1 as its main target.

Aspirin ameliorates experimental autoimmune encephalomyelitis through interleukin-11-mediated protection of regulatory T cells

Multiple sclerosis (MS) is a human disease that results from autoimmune T cells targeting myelin protein that is expressed within the central nervous system. In MS, the number of FoxP3-expressing regulatory T cells (T_regs) is reduced, which facilitates the activation of autoreactive T cells. Because aspirin (acetylsalicylic acid) is the most widely used nonsteroidal anti-inflammatory drug, we examined its immunomodulatory effect in mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. We found that low-dose aspirin suppressed the clinical symptoms of EAE in mouse models of both relapsing-remitting and chronic disease. Aspirin reduced the development of EAE driven by myelin basic protein (MBP)-specific T cells and the associated perivascular cuffing, inflammation, and demyelination. The effects of aspirin required the presence of CD25⁺FoxP3⁺ T_regs Aspirin increased the amounts of Foxp3 and interleukin-4 (IL-4) in T cells and suppressed the differentiation of naïve T cells into T helper 17 (T_H17) and T_H1 cells. Aspirin also increased the transcription of Il11 mediated by the transcription factor CREB, which was necessary for the generation of T_regs Neutralization of IL-11 negated the effects of aspirin on T_reg development and exacerbated EAE. Furthermore, we found that IL-11 alone was sufficient to maintain the percentage of FoxP3⁺ T_regs and protect mice from EAE. These results identify a previously uncharacterized mode of action of aspirin.

Low-Dose Aspirin Upregulates Tyrosine Hydroxylase and Increases Dopamine Production in Dopaminergic Neurons: Implications for Parkinson's Disease

Increasing the function of residual dopaminergic neurons in the nigra of PD patients is an important area of research as it may eventually compensate the loss. Although tyrosine hydroxylase (TH) is the rate-limiting enzyme in the dopamine (DA) biosynthesis pathway, there are no effective drugs/molecules to upregulate TH and increase the production of DA in nigral dopaminergic neurons. This study underlines the importance of aspirin in stimulating the expression of TH and increasing the level of DA in dopaminergic neurons. At low doses, aspirin increased the expression of TH and the production of DA in mouse MN9D dopaminergic neuronal cells. Accordingly, oral administration of aspirin increased the expression of TH in the nigra and upregulated the level of DA in striatum of normal C57/BL6 mice and aged A53T α-syn transgenic mice. Oral aspirin also improved locomotor activities of normal mice and A53T transgenic mice. While investigating mechanisms, we found the presence of cAMP response element (CRE) in the promoter of TH gene and the rapid induction of cAMP response element binding (CREB) activation by aspirin in dopaminergic neuronal cells. Aspirin treatment also increased the level of phospho-CREB in the nigra of C57/BL6 mice. The abrogation of aspirin-induced expression of TH by siRNA knockdown of CREB and the recruitment of CREB to the TH gene promoter by aspirin suggest that aspirin stimulates the transcription of TH in dopaminergic neurons via CREB. These results highlight a new property of aspirin in stimulating the TH-DA pathway, which may be beneficial in PD patients. Graphical Abstract ᅟ.

Layer-by-layer Polyelectrolytes Coating of Alginate Microgels for Sustained Release of Sodium Benzoate and Zosteric Acid

The potential of sustaining release of very small (Mw < 250 g/mol) hydrophilic drugs up to several days from layer-by-layer (LbL) polyelectrolyte coated alginate microgels (Alg-Ms) was investigated. One purpose is to minimize post-surgical adhesions, which develop in 12 h to 3 days after surgery. The LbL polyelectrolyte layer would serve as a diffusion barrier for their release. The LbL polyelectrolyte bilayers were prepared using poly(allylamine) (PAH) and poly(styrene sulfonate) (PSS). Sodium benzoate (NaB, Mw = 144 g/mol) and zosteric acid (ZA, Mw = 244 g/mol), two anti-inflammatory and anti-microbial compounds, were used as model drugs. A higher number of PAH/PSS bilayer lead to a greater sustained release of both drugs, and with 4 bilayers, the release of NaB and ZA was prolonged from 24 h to 72 h and 120 h, respectively. Fitting the data to the Ritger-Peppas' equation showed that as the bilayer number increased, the release constant and/or exponent decreased, indicating the LbL PAH/PSS bilayer effectively reduced the permeability of these two very small hydrophilic drugs. The ability to prolong the release of such small hydrophilic molecules, which has rarely been investigated previously, would find broad applications in fields such as anti-adhesion treatment and antifouling coatings.

Food Additive Sodium Benzoate (NaB) Activates NFκB and Induces Apoptosis in HCT116 Cells

NaB, the metabolite of cinnamon and sodium salt of benzoic acid is a commonly used food and beverage preservative. Various studies have investigated NaB for its effects on different cellular models. However, the effects of NaB on cancer cell viability signaling is substantially unknown. In this study, the effects of NaB on viability parameters and NFκB, one of the most important regulators in apoptosis, were examined in HCT116 colon cancer cells. Cell culture, light microscopy, spectrophotometry, flow cytometry, and western blot were used as methods to determine cell viability, caspase-3 activity, NFκB, Bcl-xl, Bim, and PARP proteins, respectively. NaB (6.25 mM–50 mM) treatment inhibited cell viability by inducing apoptosis, which was evident with increased Annexin V-PE staining and caspase-3 activity. NFκB activation accompanied the induction of apoptosis in NaB treated cells. Inhibition of NFκB with BAY 11-7082 did not show a pronounced effect on cell viability but induced a more apoptotic profile, which was confirmed by increased PARP fragmentation and caspase-3 activity. This effect was mostly evident at 50 mM concentration of NaB. Bcl-xl levels were not affected by NaB or BAY 11-7082/NaB treatment; whereas, total Bim increased with NaB treatment. Inhibition of NFκB activity further increased Bim levels. Overall, these results suggest that NaB induces apoptosis and activates NFκB in HCT116 colon cancer cells. Activation of NFκB emerges as target in an attempt to protect cells against apoptosis.

Dietary naringenin supplementation attenuates experimental autoimmune encephalomyelitis by modulating autoimmune inflammatory responses in mice

Autoimmune disease is highly prevalent in humans. Since conventional therapies have limited efficacy and often come with significant side effects, nutrition may provide an alternative and complementary approach to improving autoimmune disorders. Naringenin, a flavonoid found in citrus fruits, has been shown to have anti-inflammatory and antioxidant properties. Using the experimental autoimmune encephalomyelitis (EAE), a rodent model of human multiple sclerosis, we determined the effect of dietary naringenin (0.5%) on autoimmune disease. We found that naringenin reduced the incidence, delayed the onset, and attenuated the symptoms of EAE, which were accompanied by reduced immune cell infiltration and demyelination in the spinal cord. Additionally, the pro-inflammatory CD4⁺ T cell subsets Th1, Th9, and Th17 cells together with their respective transcription factors T-bet, PU.1, and RORγt were reduced in both the central nervous system (CNS) and lymph nodes of EAE mice fed naringenin while no difference was found in Th2 and regulatory T cell (Treg) populations in either CNS or lymph nodes between the two groups. We further showed that pathologic T cell proliferation induced by ex vivo re-stimulation with MOG_35-55 and proinflammatory cytokines IL-6 and TNF-α were lower in naringenin-fed mice than in the control mice. Additionally, we found that naringenin treatment inhibited mRNA expression of CXCL10 (Th1 recruiting chemokine), vascular cell adhesion molecule-1 (VCAM-1), and VLA-4 (VCAM-1 ligand) in the CNS of EAE mice. Altogether, these results indicate that naringenin may have a potential to ameliorate autoimmune disease by favorably modulating autoimmune response.

Assessment of the Target Engagement and D-Serine Biomarker Profiles of the D-Amino Acid Oxidase Inhibitors Sodium Benzoate and PGM030756

Irregular N-methyl-D-aspartate receptor (NMDAR) function is one of the main hypotheses employed to facilitate understanding of the underlying disease state of schizophrenia. Although direct agonism of the NMDAR has not yielded promising therapeutics, advances have been made by modulating the NMDAR co-agonist site which is activated by glycine and D-serine. One approach to activate the co-agonist site is to increase synaptic D-serine levels through inhibition of D-amino acid oxidase (DAO), the major catabolic clearance pathway for this and other D-amino acids. A number of DAO inhibitors have been developed but most have not entered clinical trials. One exception to this is sodium benzoate which has demonstrated efficacy in small trials of schizophrenia and Alzheimer's disease. Herein we provide data on the effect of sodium benzoate and an optimised Takeda compound, PGM030756 on ex vivo DAO enzyme occupancy and cerebellar D-serine levels in mice. Both compounds achieve high levels of enzyme occupancy; although lower doses of PGM030756 (1, 3 and 10 mg/kg) were required to achieve this compared to sodium benzoate (300, 1000 mg/kg). Cerebellar D-serine levels were increased by both agents with a delay of approximately 6 h after dosing before the peak effect was achieved. Our data and methods may be useful in understanding the effects of sodium benzoate that have been seen in clinical trials of schizophrenia and Alzheimer's disease and to support the potential clinical assessment of other DAO inhibitors, such as PGM030756, which demonstrate good enzyme occupancy and D-serine increases following administration of low oral doses.

Microfibrillar Polysaccharide-Derived Biochars as Sodium Benzoate Adsorbents

Microfibrillar biochars of chitin (CTF), chitosan (CSF), and cellulose (CLF) were fabricated via green homogenization and a pyrolysis process, and were subsequently explored as adsorbents for removing over-released sodium benzoate (SB) in aqueous systems. The structure, composition, morphology, and adsorption behavior of the as-fabricated biochars were characterized. Results suggest that all biochars, with a microscaled fibrillar structure and foam-like network morphology, underwent severe chemical transition during the pyrolysis process, thereby causing an enhancement of the Brunauer-Emmett-Teller surface area, pore volume, and aromatic and carbonaceous composition. Consequently, N-doped porous CTF/CSF microfibrillar biochars displayed a distinguished capture capacity toward SB compared to that of their fibrillar precursors. Tailoring the chemical composition, porous structure, and sorption mechanism constitutes a possible strategy to achieve adequate structural effects of polysaccharide microfibrillar chars for potential application in environmental treatment or bioenergy.

Food additives: Sodium benzoate, potassium sorbate, azorubine, and tartrazine modify the expression of NFκB, GADD45α, and MAPK8 genes

It has been reported that some of the food additives may cause sensitization, inflammation of tissues, and potentially risk factors in the development of several chronic diseases. Thus, we hypothesized that expressions of common inflammatory molecules - known to be involved in the development of various inflammatory conditions and cancers - are affected by these food additives. We investigated the effects of commonly used food preservatives and artificial food colorants based on the expressions of NFκB, GADD45α, and MAPK8 (JNK1) from the tissues of liver. RNA was isolated based on Trizol protocol and the activation levels were compared between the treated and the control groups. Tartrazine alone could elicit effects on the expressions of NFκB (p = 0.013) and MAPK8 (p = 0.022). Azorubine also resulted in apoptosis according to MAPK8 expression (p = 0.009). Preservatives were anti-apoptotic in high dose. Sodium benzoate (from low to high doses) dose-dependently silenced MAPK8 expression (p = 0.004 to p = 0.002). Addition of the two preservatives together elicited significantly greater expression of MAPK8 at half-fold dose (p = 0.002) and at fivefold dose (p = 0.008). This study suggests that some of the food preservatives and colorants can contribute to the activation of inflammatory pathways.

Urinary Urea, Uric Acid and Hippuric Acid as Potential Biomarkers in Multiple Sclerosis Patients

Urine is a proven source of metabolite biomarkers and has the potential to be a rapid, noninvasive, inexpensive, and efficient diagnostic tool for various human diseases. Despite these advantages, urine is an under-investigated source of biomarkers for multiple sclerosis (MS). The objective was to investigate the level of some urinary metabolites (urea, uric acid and hippuric acid) in patients with MS and correlate their levels to the severity of the disease, MS subtypes and MS treatment. The urine samples were collected from 73 MS patients-48 with RRMS and 25 with SPMS- and age matched 75 healthy controls. The values of urinary urea, uric acid and hippuric acid in MS patients were significantly decreased, and these metabolites in SPMS pattern showed significantly decrease than RRMS pattern. Also showed significant inverse correlation with expanded disability status scale and number of relapses. Accordingly, they may act as a potential urinary biomarkers for MS, and correlate to disease progression.

Nebulization of RNS60, a Physically-Modified Saline, Attenuates the Adoptive Transfer of Experimental Allergic Encephalomyelitis in Mice: Implications for Multiple Sclerosis Therapy

Developing a new and effective therapeutic approach against multiple sclerosis (MS) is always an important area of research. RNS60 is a bioactive aqueous solution generated by subjecting normal saline to Taylor-Couette-Poiseuille flow under elevated oxygen pressure. Recently we have demonstrated that RNS60, administered through intraperitoneal injection, ameliorated clinical symptoms and disease progression of experimental allergic encephalomyelitis (EAE), an animal model of MS. Since the intravenous route is not preferred for treating a chronic condition, we tested if nebulization of RNS60 could attenuate the disease process of adoptively-transferred EAE in mice. Although we could not directly image RNS60 after nebulization, nebulized Alexa680 reached spleen, spinal cord and different parts of the brain. Nebulization of RNS60 starting from the acute phase attenuated clinical symptoms of relapsing-remitting EAE in female SJL/J mice. RNS60 nebulization also inhibited perivascular cuffing, maintained the integrity of blood-brain and blood-spinal cord barriers, suppressed inflammation, normalized the expression of myelin genes, and blocked demyelination in the CNS of EAE mice. On the immunomodulatory front, nebulization of RNS60 to EAE mice led to the enrichment of anti-autoimmune regulatory T cells (Tregs) and suppression of autoimmune Th17 cells. Together, these results suggest that nebulization of RNS60 may be used to control aberrant immune responses in MS and other autoimmune disorders.

Glyceryl Tribenzoate: A Flavoring Ingredient, Inhibits the Adoptive Transfer of Experimental Allergic Encephalomyelitis via TGF-β: Implications for Multiple Sclerosis Therapy

Multiple sclerosis (MS) is the most common autoimmune demyelinating disease of the central nervous system (CNS). Here, we have explored a novel use of glyceryl tribenzoate (GTB), a flavoring ingredient, in ameliorating the disease process of experimental allergic encephalomyelitis (EAE), an animal model of MS, via TGF-β. Oral feeding of GTB suppressed clinical symptoms of adoptively-transferred relapsing-remitting (RR) EAE in recipient mice and suppressed the generation of encephalitogenic T cells in donor mice. GTB also attenuated clinical symptoms of RR-EAE in PLP-TCR transgenic mice and chronic EAE in male C57/BL6 mice. Accordingly, GTB also suppressed perivascular cuffing, preserved the integrity of blood-brain barrier and blood-spinal cord barrier, inhibited inflammation, and stopped demyelination in the CNS of EAE mice. Interestingly, GTB treatment upregulated TGF-β and enriched regulatory T cells (Tregs) in splenocytes as well as in vivo in EAE mice. Blocking TGF-β by neutralizing antibodies abrogated GTB-mediated enrichment of Tregs and protection of EAE. These results suggest that oral GTB may be considered as a possible therapy for MS patients.

Sodium Benzoate, a Food Additive and a Metabolite of Cinnamon, Enriches Regulatory T Cells via STAT6-Mediated Upregulation of TGF-β

Upregulation and/or maintenance of regulatory T cells (Tregs) during autoimmune insults may have therapeutic efficacy in autoimmune diseases. Earlier we have reported that sodium benzoate (NaB), a metabolite of cinnamon and a Food and Drug Administration-approved drug against urea cycle disorders, upregulates Tregs and protects mice from experimental allergic encephalomyelitis, an animal model of multiple sclerosis. However, mechanisms by which NaB increases Tregs are poorly understood. Because TGF-β is an important inducer of Tregs, we examined the effect of NaB on the status of TGF-β. In this study, we demonstrated that NaB induced the expression of TGF-β mRNA and protein in normal as well as proteolipid protein-primed splenocytes. The presence of a consensus STAT6 binding site in the promoter of the TGF-β gene, activation of STAT6 in splenocytes by NaB, recruitment of STAT6 to the TGF-β promoter by NaB, and abrogation of NaB-induced expression of TGF-β in splenocytes by small interfering RNA knockdown of STAT6 suggest that NaB induces the expression of TGF-β via activation of STAT6. Furthermore, we demonstrated that blocking of TGF-β by neutralizing Abs abrogated NaB-mediated protection of Tregs and experimental allergic encephalomyelitis. These studies identify a new function of NaB in upregulating TGF-β via activation of STAT6, which may be beneficial in MS patients.

Cinnamon Converts Poor Learning Mice to Good Learners: Implications for Memory Improvement

This study underlines the importance of cinnamon, a commonly used natural spice and flavoring material, and its metabolite sodium benzoate (NaB) in converting poor learning mice to good learning ones. NaB, but not sodium formate, was found to upregulate plasticity-related molecules, stimulate NMDA- and AMPA-sensitive calcium influx and increase of spine density in cultured hippocampal neurons. NaB induced the activation of CREB in hippocampal neurons via protein kinase A (PKA), which was responsible for the upregulation of plasticity-related molecules. Finally, spatial memory consolidation-induced activation of CREB and expression of different plasticity-related molecules were less in the hippocampus of poor learning mice as compared to good learning ones. However, oral treatment of cinnamon and NaB increased spatial memory consolidation-induced activation of CREB and expression of plasticity-related molecules in the hippocampus of poor-learning mice and converted poor learners into good learners. These results describe a novel property of cinnamon in switching poor learners to good learners via stimulating hippocampal plasticity.

Sodium benzoate, a food preservative, affects the functional and activation status of splenocytes at non cytotoxic dose

Sodium benzoate (SB) is a widely used food preservative due to its bacteriostatic and fungistatic properties. The acceptable daily intake of SB is 5 mg/kg-bw, however, it has been found to be used in the food commodities at relatively high levels (2119 mg/kg). Earlier studies on SB have shown its immunosuppressive properties, but comprehensive immunotoxicity data is lacking. Our studies have shown that SB was non cytotoxic in splenocytes up to 1000 μg/ml for 72 h, however at 2500 μg/ml it was found to be cytotoxic. Thus, 1000 μg/ml dose of SB was chosen for the subsequent experiments. SB significantly suppresses the proliferation of Con A and LPS stimulated splenocytes at 72 h, while allogenic response of T cells was significantly decreased after 96 h. SB did not affect the relative expression of CD3e or CD4 molecules following 72 h exposure, however, it downregulated the relative expression of CD8 co-receptor. Further, exposure of splenocytes to SB for 72 h led to reduced expression of CD28 and CD95, which play a vital role in T cell activation. SB also suppresses the relative expression of CD19, CD40 and CD95 receptors on B cells after 72 h. In addition to the functional responses, SB lowered the expression of IL4, IL6, IFNγ and IL17 cytokines in Con A stimulated splenocytes; and IL6, IFNγ and TNFα in LPS stimulated splenocytes following 48 h of exposure. Taken together, the present study is suggestive of the immunomodulatory potential of SB.

Sodium Benzoate, a Metabolite of Cinnamon and a Food Additive, Upregulates Ciliary Neurotrophic Factor in Astrocytes and Oligodendrocytes

Ciliary neurotrophic factor (CNTF) is a promyelinating trophic factor that plays an important role in multiple sclerosis (MS). However, mechanisms by which CNTF expression could be increased in the brain are poorly understood. Recently we have discovered anti-inflammatory and immunomodulatory activities of sodium benzoate (NaB), a metabolite of cinnamon and a widely-used food additive. Here, we delineate that NaB is also capable of increasing the mRNA and protein expression of CNTF in primary mouse astrocytes and oligodendrocytes and primary human astrocytes. Accordingly, oral administration of NaB and cinnamon led to the upregulation of astroglial and oligodendroglial CNTF in vivo in mouse brain. Induction of experimental allergic encephalomyelitis, an animal model of MS, reduced the level of CNTF in the brain, which was restored by oral administration of cinnamon. While investigating underlying mechanisms, we observed that NaB induced the activation of protein kinase A (PKA) and H-89, an inhibitor of PKA, abrogated NaB-induced expression of CNTF. The activation of cAMP response element binding (CREB) protein by NaB, the recruitment of CREB and CREB-binding protein to the CNTF promoter by NaB and the abrogation of NaB-induced expression of CNTF in astrocytes by siRNA knockdown of CREB suggest that NaB increases the expression of CNTF via the activation of CREB. These results highlight a novel myelinogenic property of NaB and cinnamon, which may be of benefit for MS and other demyelinating disorders.

Cinnamon and Its Metabolite Sodium Benzoate Attenuate the Activation of p21rac and Protect Memory and Learning in an Animal Model of Alzheimer's Disease

This study underlines the importance of cinnamon, a commonly used natural spice and flavoring material, and its metabolite sodium benzoate (NaB) in attenuating oxidative stress and protecting memory and learning in an animal model of Alzheimer’s disease (AD). NaB, but not sodium formate, was found to inhibit LPS-induced production of reactive oxygen species (ROS) in mouse microglial cells. Similarly, NaB also inhibited fibrillar amyloid beta (Aβ)- and 1-methyl-4-phenylpyridinium(+)-induced microglial production of ROS. Although NaB reduced the level of cholesterol in vivo in mice, reversal of the inhibitory effect of NaB on ROS production by mevalonate, and geranylgeranyl pyrophosphate, but not cholesterol, suggests that depletion of intermediates, but not end products, of the mevalonate pathway is involved in the antioxidant effect of NaB. Furthermore, we demonstrate that an inhibitor of p21^rac geranylgeranyl protein transferase suppressed the production of ROS and that NaB suppressed the activation of p21^rac in microglia. As expected, marked activation of p21^rac was observed in the hippocampus of subjects with AD and 5XFAD transgenic (Tg) mouse model of AD. However, oral feeding of cinnamon (Cinnamonum verum) powder and NaB suppressed the activation of p21^rac and attenuated oxidative stress in the hippocampus of Tg mice as evident by decreased dihydroethidium (DHE) and nitrotyrosine staining, reduced homocysteine level and increased level of reduced glutathione. This was accompanied by suppression of neuronal apoptosis, inhibition of glial activation, and reduction of Aβ burden in the hippocampus and protection of memory and learning in transgenic mice. Therefore, cinnamon powder may be a promising natural supplement in halting or delaying the progression of AD.

Activation of peroxisome proliferator-activated receptor α induces lysosomal biogenesis in brain cells: implications for lysosomal storage disorders

Lysosomes are ubiquitous membrane-enclosed organelles filled with an acidic interior and are central to the autophagic, endocytic, or phagocytic pathway. In contrast to its classical function as the waste management machinery, lysosomes are now considered to be an integral part of various cellular signaling processes. The diverse functionality of this single organelle requires a very complex and coordinated regulation of its activity with transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, at its core. However, mechanisms by which TFEB is regulated are poorly understood. This study demonstrates that gemfibrozil, an agonist of peroxisome proliferator-activated receptor (PPAR) α, alone and in conjunction with all-trans-retinoic acid is capable of enhancing TFEB in brain cells. We also observed that PPARα, but not PPARβ and PPARγ, is involved in gemfibrozil-mediated up-regulation of TFEB. Reporter assay and chromatin immunoprecipitation studies confirmed the recruitment of retinoid X receptor α, PPARα, and PGC1α on the PPAR-binding site on the Tfeb promoter as well. Subsequently, the drug-mediated induction of TFEB caused an increase in lysosomal protein and the lysosomal abundance in cell. Collectively, this study reinforces the link between lysosomal biogenesis and lipid metabolism with TFEB at the crossroads. Furthermore, gemfibrozil may be of therapeutic value in the treatment of lysosomal storage disorders in which autophagy-lysosome pathway plays an important role.

Cinnamon ameliorates experimental allergic encephalomyelitis in mice via regulatory T cells: implications for multiple sclerosis therapy

Upregulation and/or maintenance of regulatory T cells (Tregs) during an autoimmune insult may have therapeutic efficacy in autoimmune diseases. Although several immunomodulatory drugs and molecules are available, most present significant side effects over long-term use. Cinnamon is a commonly used natural spice and flavoring material used for centuries throughout the world. Here, we have explored a novel use of cinnamon powder in protecting Tregs and treating the disease process of experimental allergic encephalomyelitis (EAE), an animal model of MS. Oral feeding of cinnamon (Cinnamonum verum) powder suppresses clinical symptoms of relapsing-remitting EAE in female PLP-TCR transgenic mice and adoptive transfer mouse model. Cinnamon also inhibited clinical symptoms of chronic EAE in male C57/BL6 mice. Dose-dependent study shows that cinnamon powder at a dose of 50 mg/kg body wt/d or higher significantly suppresses clinical symptoms of EAE in mice. Accordingly, oral administration of cinnamon also inhibited perivascular cuffing, maintained the integrity of blood-brain barrier and blood-spinal cord barrier, suppressed inflammation, normalized the expression of myelin genes, and blocked demyelination in the central nervous system of EAE mice. Interestingly, cinnamon treatment upregulated Tregs via reduction of nitric oxide production. Furthermore, we demonstrate that blocking of Tregs by neutralizing antibodies against CD25 abrogates cinnamon-mediated protection of EAE. Taken together, our results suggest that oral administration of cinnamon powder may be beneficial in MS patients and that no other existing anti-MS therapies could be so economical and trouble-free as this approach.

Uses of complementary and alternative medicine in multiple sclerosis

Multiple sclerosis (MS) is a chronic, disabling, recurrent demyelination of the central nervous system (CNS). It could affect different regions in the brain and spinal cord, and according to the domain which is affected, it could cause different symptoms such as motor, sensory, or visual impairment; fatigue; bowel, bladder, and sexual dysfunction; cognitive impairment; and depression. MS patients also face reduced quality of life. Drugs that are used in MS are not fully efficient and patients suffer from many symptoms and adverse effects. Today there is an increasing trend of using complementary and alternative medicine (CAM). People are more likely to use this type of treatment. Using appropriate lifestyle and CAM therapy can subside some of the symptoms and could improve the quality of life in these patients. Many people with MS explore CAM therapies for their symptoms. This review is aimed to introduce CAM therapies that could be used in MS patients.

Cinnamon treatment upregulates neuroprotective proteins Parkin and DJ-1 and protects dopaminergic neurons in a mouse model of Parkinson's disease

Upregulation and/or maintenance of Parkinson's disease (PD)-related beneficial proteins such as Parkin and DJ-1 in astrocytes during neurodegenerative insults may have therapeutic efficacy in PD. Cinnamon is a commonly used natural spice and flavoring material throughout the world. Here we have explored a novel use of cinnamon in upregulating Parkin and DJ-1 and protecting dopaminergic neurons in MPTP mouse model of PD. Recently we have delineated that oral feeding of cinnamon (Cinnamonum verum) powder produces sodium benzoate (NaB) in blood and brain of mice. Proinflammatory cytokine IL-1β decreased the level of Parkin/DJ-1 in mouse astrocytes. However, cinnamon metabolite NaB abrogated IL-1β-induced loss of these proteins. Inability of TNF-α to produce nitric oxide (NO) and decrease the level of Parkin/DJ-1 in wild type (WT) astrocytes, failure of IL-1β to reduce Parkin/DJ-1 in astrocytes isolated from iNOS (-/-) mice, and decrease in Parkin/DJ-1 in WT astrocytes by NO donor DETA-NONOate suggest that NO is a negative regulator of Parkin/DJ-1. Furthermore, suppression of IL-1β-induced expression of iNOS in astrocytes by NaB and reversal of NaB-mediated protection of Parkin/DJ-1 by DETA-NONOate in astrocytes indicate that NaB protects Parkin/DJ-1 in activated astrocytes via suppressing iNOS. Similarly MPTP intoxication also increased the level of iNOS and decreased the level of Parkin/DJ-1 in vivo in the nigra. However, oral treatment of MPTP-intoxicated mice with cinnamon powder and NaB reduced the expression of iNOS and protected Parkin/DJ-1 in the nigra. These findings paralleled dopaminergic neuronal protection, normalized striatal neurotransmitters, and improved motor functions by cinnamon in MPTP-intoxicated mice. These results suggest that cinnamon may be beneficial for PD patients.

Altered spinal microRNA-146a and the microRNA-183 cluster contribute to osteoarthritic pain in knee joints

The objective of this study was to examine whether altered expression of microRNAs in central nervous system components is pathologically linked to chronic knee joint pain in osteoarthritis. A surgical animal model for knee joint OA was generated by medial meniscus transection in rats followed by behavioral pain tests. Relationships between pathological changes in knee joint and development of chronic joint pain were examined by histology and imaging analyses. Alterations in microRNAs associated with OA-evoked pain sensation were determined in bilateral lumbar dorsal root ganglia (DRG) and the spinal dorsal horn by microRNA array followed by individual microRNA analyses. Gain- and loss-of-function studies of selected microRNAs (miR-146a and miR-183 cluster) were conducted to identify target pain mediators regulated by these selective microRNAs in glial cells. The ipsilateral hind leg displayed significantly increased hyperalgesia after 4 weeks of surgery, and sensitivity was sustained for the remainder of the 8-week experimental period (F = 341, p < 0.001). The development of OA-induced chronic pain was correlated with pathological changes in the knee joints as assessed by histological and imaging analyses. MicroRNA analyses showed that miR-146a and the miR-183 cluster were markedly reduced in the sensory neurons in DRG (L4/L5) and spinal cord from animals experiencing knee joint OA pain. The downregulation of miR-146a and/or the miR-183 cluster in the central compartments (DRG and spinal cord) are closely associated with the upregulation of inflammatory pain mediators. The corroboration between decreases in these signature microRNAs and their specific target pain mediators were further confirmed by gain- and loss-of-function analyses in glia, the major cellular component of the central nervous system (CNS). MicroRNA therapy using miR-146a and the miR-183 cluster could be powerful therapeutic intervention for OA in alleviating joint pain and concomitantly regenerating peripheral knee joint cartilage.

Up-regulation of neurotrophic factors by cinnamon and its metabolite sodium benzoate: therapeutic implications for neurodegenerative disorders

This study underlines the importance of cinnamon, a widely-used food spice and flavoring material, and its metabolite sodium benzoate (NaB), a widely-used food preservative and a FDA-approved drug against urea cycle disorders in humans, in increasing the levels of neurotrophic factors [e.g., brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3)] in the CNS. NaB, but not sodium formate (NaFO), dose-dependently induced the expression of BDNF and NT-3 in primary human neurons and astrocytes. Interestingly, oral administration of ground cinnamon increased the level of NaB in serum and brain and upregulated the levels of these neurotrophic factors in vivo in mouse CNS. Accordingly, oral feeding of NaB, but not NaFO, also increased the level of these neurotrophic factors in vivo in the CNS of mice. NaB induced the activation of protein kinase A (PKA), but not protein kinase C (PKC), and H-89, an inhibitor of PKA, abrogated NaB-induced increase in neurotrophic factors. Furthermore, activation of cAMP response element binding (CREB) protein, but not NF-κB, by NaB, abrogation of NaB-induced expression of neurotrophic factors by siRNA knockdown of CREB and the recruitment of CREB and CREB-binding protein to the BDNF promoter by NaB suggest that NaB exerts its neurotrophic effect through the activation of CREB. Accordingly, cinnamon feeding also increased the activity of PKA and the level of phospho-CREB in vivo in the CNS. These results highlight a novel neutrophic property of cinnamon and its metabolite NaB via PKA - CREB pathway, which may be of benefit for various neurodegenerative disorders.