Physiological concentrations of cyanide stimulate mitochondrial Complex IV and enhance cellular bioenergetics.

In mammalian cells, cyanide is viewed as a cytotoxic agent, which exerts its effects through inhibition of mitochondrial Complex IV (Cytochrome C oxidase [CCOx]). However, the current report demonstrates that cyanide's effect on CCOx is biphasic; low (nanomolar to low-micromolar) concentrations stimulate CCOx activity, while higher (high-micromolar) concentrations produce the "classic" inhibitory effect. Low concentrations of cyanide stimulated mitochondrial electron transport and elevated intracellular adenosine triphosphate (ATP), resulting in the stimulation of cell proliferation. The stimulatory effect of cyanide on CCOx was associated with the removal of the constitutive, inhibitory glutathionylation on its catalytic 30- and 57-kDa subunits. Transfer of diluted Pseudomonas aeruginosa (a cyanide-producing bacterium) supernatants to mammalian cells stimulated cellular bioenergetics, while concentrated supernatants were inhibitory. These effects were absent with supernatants from mutant Pseudomonas lacking its cyanide-producing enzyme. These results raise the possibility that cyanide at low, endogenous levels serves regulatory purposes in mammals. Indeed, the expression of six putative mammalian cyanide-producing and/or -metabolizing enzymes was confirmed in HepG2 cells; one of them (myeloperoxidase) showed a biphasic regulation after cyanide exposure. Cyanide shares features with "classical" mammalian gasotransmitters NO, CO, and H2S and may be considered the fourth mammalian gasotransmitter.

Epigallocatechin gallate is a potent inhibitor of cystathionine beta-synthase: Structure-activity relationship and mechanism of action.

Epigallocatechin gallate (EGCG) is the main bioactive component of green tea. Through screening of a small library of natural compounds, we discovered that EGCG inhibits cystathionine ß-synthase (CBS), a major H2S-generating enzyme. Here we characterize EGCG's mechanism of action in the context of CBS-derived H2S production. In the current project, biochemical, pharmacological and cell biology approaches were used to characterize the effect of EGCG on CBS in cellular models of cancer and Down syndrome (DS). The results show that EGCG binds to CBS and inhibits H2S-producing CBS activity almost 30-times more efficiently than the canonical cystathionine formation (IC50 0.12 versus 3.3 µM). Through screening structural analogs and building blocks, we identified that gallate moiety of EGCG represents the pharmacophore responsible for CBS inhibition. EGCG is a mixed-mode, CBS-specific inhibitor with no effect on the other two major enzymatic sources of H2S, CSE and 3-MST. Unlike the prototypical CBS inhibitor aminooxyacetate, EGCG does not bind the catalytic cofactor of CBS pyridoxal-5'-phosphate. Molecular modeling suggests that EGCG blocks a substrate access channel to pyridoxal-5'-phosphate. EGCG inhibits cellular H2S production in HCT-116 colon cancer cells and in DS fibroblasts. It also exerts effects that are consistent with the functional role of CBS in these cells: in HCT-116 cells it decreases, while in DS cells it improves viability and proliferation. In conclusion, EGCG is a potent inhibitor of CBS-derived H2S production. This effect may contribute to its pharmacological effects in various pathophysiological conditions.

Overproduction of H2S, generated by CBS, inhibits mitochondrial Complex IV and suppresses oxidative phosphorylation in Down syndrome.

Down syndrome (DS) is associated with significant perturbances in mitochondrial function. Here we tested the hypothesis that the suppression of mitochondrial electron transport in DS cells is due to high expression of cystathionine-ß-synthase (CBS) and subsequent overproduction of the gaseous transmitter hydrogen sulfide (H2S). Fibroblasts from DS individuals showed higher CBS expression than control cells; CBS localization was both cytosolic and mitochondrial. DS cells produced significantly more H2S and polysulfide and exhibited a profound suppression of mitochondrial electron transport, oxygen consumption, and ATP generation. DS cells also exhibited slower proliferation rates. In DS cells, pharmacological inhibition of CBS activity with aminooxyacetate or siRNA-mediated silencing of CBS normalized cellular H2S levels, restored Complex IV activity, improved mitochondrial electron transport and ATP synthesis, and restored cell proliferation. Thus, CBS-derived H2S is responsible for the suppression of mitochondrial function in DS cells. When H2S overproduction is corrected, the tonic suppression of Complex IV is lifted, and mitochondrial electron transport is restored. CBS inhibition offers a potential approach for the pharmacological correction of DS-associated mitochondrial dysfunction.

Pharmacological induction of mesenchymal-epithelial transition via inhibition of H2S biosynthesis and consequent suppression of ACLY activity in colon cancer cells.

Hydrogen sulfide (H2S) is an important endogenous gaseous transmitter mediator, which regulates a variety of cellular functions in autocrine and paracrine manner. The enzymes responsible for the biological generation of H2S include cystathionine-ß-synthase (CBS), cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST). Increased expression of these enzymes and overproduction of H2S has been implicated in essential processes of various cancer cells, including the stimulation of metabolism, maintenance of cell proliferation and cytoprotection. Cancer cell identity is characterized by so-called "transition states". The progression from normal (epithelial) to transformed (mesenchymal) state is termed epithelial-to-mesenchymal transition (EMT) whereby epithelial cells lose their cell-to-cell adhesion capacity and gain mesenchymal characteristics. The transition process can also proceed in the opposite direction, and this process is termed mesenchymal-to-epithelial transition (MET). The current project was designed to determine whether inhibition of endogenous H2S production in colon cancer cells affects the EMT/MET balance in vitro. Inhibition of H2S biosynthesis in HCT116 human colon cancer cells was achieved either with aminooxyacetic acid (AOAA) or 2-[(4-hydroxy-6-methylpyrimidin-2-yl)sulfanyl]-1-(naphthalen-1-yl)ethan-1-one (HMPSNE). These inhibitors induced an upregulation of E-cadherin and Zonula occludens-1 (ZO-1) expression and downregulation of fibronectin expression, demonstrating that H2S biosynthesis inhibitors can produce a pharmacological induction of MET in colon cancer cells. These actions were functionally reflected in an inhibition of cell migration, as demonstrated in an in vitro "scratch wound" assay. The mechanisms involved in the action of endogenously produced H2S in cancer cells in promoting (or maintaining) EMT (or tonically inhibiting MET) relate, at least in part, in the induction of ATP citrate lyase (ACLY) protein expression, which occurs via upregulation of ACLY mRNA (via activation of the ACLY promoter). ACLY in turn, regulates the Wnt-ß-catenin pathway, an essential regulator of the EMT/MET balance. Taken together, pharmacological inhibition of endogenous H2S biosynthesis in cancer cells induces MET. We hypothesize that this may contribute to anti-cancer / anti-metastatic effects of H2S biosynthesis inhibitors.

Neurobehavioral dysfunction in a mouse model of Down syndrome: upregulation of cystathionine ß-synthase, H2S overproduction, altered protein persulfidation, synaptic dysfunction, endoplasmic reticulum stress, and autophagy.

Down syndrome (DS) is a genetic condition where the person is born with an extra chromosome 21. DS is associated with accelerated aging; people with DS are prone to age-related neurological conditions including an early-onset Alzheimer's disease. Using the Dp(17)3Yey/ + mice, which overexpresses a portion of mouse chromosome 17, which encodes for the transsulfuration enzyme cystathionine ß-synthase (CBS), we investigated the functional role of the CBS/hydrogen sulfide (H2S) pathway in the pathogenesis of neurobehavioral dysfunction in DS. The data demonstrate that CBS is higher in the brain of the DS mice than in the brain of wild-type mice, with primary localization in astrocytes. DS mice exhibited impaired recognition memory and spatial learning, loss of synaptosomal function, endoplasmic reticulum stress, and autophagy. Treatment of mice with aminooxyacetate, a prototypical CBS inhibitor, improved neurobehavioral function, reduced the degree of reactive gliosis in the DS brain, increased the ability of the synaptosomes to generate ATP, and reduced endoplasmic reticulum stress. H2S levels in the brain of DS mice were higher than in wild-type mice, but, unexpectedly, protein persulfidation was decreased. Many of the above alterations were more pronounced in the female DS mice. There was a significant dysregulation of metabolism in the brain of DS mice, which affected amino acid, carbohydrate, lipid, endocannabinoid, and nucleotide metabolites; some of these alterations were reversed by treatment of the mice with the CBS inhibitor. Thus, the CBS/H2S pathway contributes to the pathogenesis of neurological dysfunction in DS in the current animal model.

Incretin Mimetics Restore the ER-Mitochondrial Axis and Switch Cell Fate Towards Survival in LUHMES Dopaminergic-Like Neurons: Implications for Novel Therapeutic Strategies in Parkinson's Disease.

BACKGROUND: Parkinson's disease (PD) is a progressive neurodegenerative movement disorder that afflicts more than 10 million people worldwide. Available therapeutic interventions do not stop disease progression. The etiopathogenesis of PD includes unbalanced calcium dynamics and chronic dysfunction of the axis of the endoplasmic reticulum (ER) and mitochondria that all can gradually favor protein aggregation and dopaminergic degeneration. OBJECTIVE: In Lund Human Mesencephalic (LUHMES) dopaminergic-like neurons, we tested novel incretin mimetics under conditions of persistent, calcium-dependent ER stress. METHODS: We assessed the pharmacological effects of Liraglutide-a glucagon-like peptide-1 (GLP-1) analog-and the dual incretin GLP-1/GIP agonist DA3-CH in the unfolded protein response (UPR), cell bioenergetics, mitochondrial biogenesis, macroautophagy, and intracellular signaling for cell fate in terminally differentiated LUHMES cells. Cells were co-stressed with the sarcoplasmic reticulum calcium ATPase (SERCA) inhibitor, thapsigargin. RESULTS: We report that Liraglutide and DA3-CH analogs rescue the arrested oxidative phosphorylation and glycolysis. They mitigate the suppressed mitochondrial biogenesis and hyper-polarization of the mitochondrial membrane, all to re-establish normalcy of mitochondrial function under conditions of chronic ER stress. These effects correlate with a resolution of the UPR and the deficiency of components for autophagosome formation to ultimately halt the excessive synaptic and neuronal death. Notably, the dual incretin displayed a superior anti-apoptotic effect, when compared to Liraglutide. CONCLUSIONS: The results confirm the protective effects of incretin signaling in ER and mitochondrial stress for neuronal degeneration management and further explain the incretin-derived effects observed in PD patients.

Inhibition of the 3-mercaptopyruvate sulfurtransferase-hydrogen sulfide system promotes cellular lipid accumulation.

H2S is generated in the adipose tissue by cystathionine γ-lyase, cystathionine ß-synthase, and 3-mercaptopyruvate sulfurtransferase (3-MST). H2S plays multiple roles in the regulation of various metabolic processes, including insulin resistance. H2S biosynthesis also occurs in adipocytes. Aging is known to be associated with a decline in H2S. Therefore, the question arises whether endogenous H2S deficiency may affect the process of adipocyte maturation and lipid accumulation. Among the three H2S-generating enzymes, the role of 3-MST is the least understood in adipocytes. Here we tested the effect of the 3-MST inhibitor 2-[(4-hydroxy-6-methylpyrimidin-2-yl)sulfanyl]-1-(naphthalen-1-yl)ethan-1-one (HMPSNE) and the H2S donor (GYY4137) on the differentiation and adipogenesis of the adipocyte-like cells 3T3-L1 in vitro. 3T3-L1 cells were differentiated into mature adipocytes in the presence of GYY4137 or HMPSNE. HMPSNE significantly enhanced lipid accumulation into the maturing adipocytes. On the other hand, suppressed lipid accumulation was observed in cells treated with the H2S donor. 3-MST inhibition increased, while H2S donation suppressed the expression of various H2S-producing enzymes during adipocyte differentiation. 3-MST knockdown also facilitated adipocytic differentiation and lipid uptake. The underlying mechanisms may involve impairment of oxidative phosphorylation and fatty acid oxidation as well as the activation of various differentiation-associated transcription factors. Thus, the 3-MST/H2S system plays a tonic role in suppressing lipid accumulation and limiting the differentiation of adipocytes. Stimulation of 3-MST activity or supplementation of H2S-which has been recently linked to various experimental therapeutic approaches during aging-may be a potential experimental approach to counteract adipogenesis.

Role of the cystathionine ß-synthase / H2S pathway in the development of cellular metabolic dysfunction and pseudohypoxia in down syndrome.

BACKGROUND: Overexpression of the transsulfuration enzyme cystathionine-ß-synthase (CBS), and overproduction of its product, hydrogen sulfide (H2S) are recognized as potential pathogenetic factors in Down syndrome (DS). The purpose of the study was to determine how the mitochondrial function and core metabolic pathways are affected by DS and how pharmacological inhibition of CBS affects these parameters. METHODS: 8 human control and 8 human DS fibroblast cell lines have been subjected to bioenergetic and fluxomic and proteomic analysis with and without treatment with a pharmacological inhibitor of CBS. RESULTS: DS cells exhibited a significantly higher CBS expression than control cells, and produced more H2S. They also exhibited suppressed mitochondrial electron transport and oxygen consumption and suppressed Complex IV activity, impaired cell proliferation and increased ROS generation. Inhibition of H2S biosynthesis with aminooxyacetic acid reduced cellular H2S, improved cellular bioenergetics, attenuated ROS and improved proliferation. 13C glucose fluxomic analysis revealed that DS cells exhibit a suppression of the Krebs cycle activity with a compensatory increase in glycolysis. CBS inhibition restored the flux from glycolysis to the Krebs cycle and reactivated oxidative phosphorylation. Proteomic analysis revealed no CBS-dependent alterations in the expression level of the enzymes involved in glycolysis, oxidative phosphorylation and the pentose phosphate pathway. DS was associated with the dysregulation of several components of the autophagy network; CBS inhibition normalized several of these parameters. CONCLUSIONS: Increased H2S generation in DS promotes pseudohypoxia and contributes to cellular metabolic dysfunction by causing a shift from oxidative phosphorylation to glycolysis.

Overproduction of hydrogen sulfide, generated by cystathionine ß-synthase, disrupts brain wave patterns and contributes to neurobehavioral dysfunction in a rat model of down syndrome.

Using a novel rat model of Down syndrome (DS), the functional role of the cystathionine-ß-synthase (CBS)/hydrogen sulfide (H2S) pathway was investigated on the pathogenesis of brain wave pattern alterations and neurobehavioral dysfunction. Increased expression of CBS and subsequent overproduction of H2S was observed in the brain of DS rats, with CBS primarily localizing to astrocytes and the vasculature. DS rats exhibited neurobehavioral defects, accompanied by a loss of gamma brain wave activity and a suppression of the expression of multiple pre- and postsynaptic proteins. Aminooxyacetate, a prototypical pharmacological inhibitor of CBS, increased the ability of the DS brain tissue to generate ATP in vitro and reversed the electrophysiological and neurobehavioral alterations in vivo. Thus, the CBS/H2S pathway contributes to the pathogenesis of neurological dysfunction in DS, most likely through dysregulation of cellular bioenergetics and gene expression.

Role of Hydrogen Sulfide and 3-Mercaptopyruvate Sulfurtransferase in the Regulation of the Endoplasmic Reticulum Stress Response in Hepatocytes.

It is estimated that over 1.5 billion people suffer from various forms of chronic liver disease worldwide. The emerging prevalence of metabolic syndromes and alcohol misuse, along with the lack of disease-modifying agents for the therapy of many severe liver conditions predicts that chronic liver disease will continue to be a major problem in the future. Better understanding of the underlying pathogenetic mechanisms and identification of potential therapeutic targets remains a priority. Herein, we explored the potential role of the 3-mercaptopyruvate sulfurtransferase/hydrogen sulfide (H2S) system in the regulation of the endoplasmic reticulum (ER) stress and of its downstream processes in the immortalized hepatic cell line HepG2 in vitro. ER stress suppressed endogenous H2S levels and pharmacological supplementation of H2S with sodium hydrogen sulfide (NaHS) mitigated many aspects of ER stress, culminating in improved cellular bioenergetics and prevention of autophagic arrest, thereby switching cells' fate towards survival. Genetic silencing of 3-MST or pharmacological inhibition of the key enzymes involved in hepatocyte H2S biosynthesis exacerbated many readouts related to ER-stress or its downstream functional responses. Our findings implicate the 3-MST/H2S system in the intracellular network that governs proteostasis and ER-stress adaptability in hepatocytes and reinforce the therapeutic potential of pharmacological H2S supplementation.

Role of 3-Mercaptopyruvate Sulfurtransferase in the Regulation of Proliferation and Cellular Bioenergetics in Human Down Syndrome Fibroblasts.

Down syndrome (trisomy of human chromosome 21) is a common genetic disorder. Overproduction of the gaseous mediator hydrogen sulfide (H2S) has been implicated in the pathogenesis of neurological and metabolic deficits associated with Down syndrome. Several lines of data indicate that an important enzyme responsible for H2S overproduction in Down syndrome is cystathionine-ß-synthase (CBS), an enzyme localized on chromosome 21. The current study explored the possibility that a second H2S-producing enzyme, 3-mercaptopyruvate sulfurtransferase (3-MST), may also contribute to the development of functional deficits of Down syndrome cells. Western blotting analysis demonstrated a significantly higher level of 3-MST protein expression in human Down syndrome fibroblasts compared to cells from healthy control individuals; the excess 3-MST was mainly localized to the mitochondrial compartment. Pharmacological inhibition of 3-MST activity improved mitochondrial electron transport and oxidative phosphorylation parameters (but did not affect the suppressed glycolytic parameters) and enhanced cell proliferation in Down syndrome cells (but not in healthy control cells). The findings presented in the current report suggest that in addition to the indisputable role of CBS, H2S produced from 3-MST may also contribute to the development of mitochondrial metabolic and functional impairments in Down syndrome cells.

Mechanism of cystathionine-ß-synthase inhibition by disulfiram: The role of bis(N,N-diethyldithiocarbamate)-copper(II).

BACKGROUND: Hydrogen sulfide (H2S) is an endogenous mammalian gasotransmitter. Cystathionine ß-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST) are the principal enzymes responsible for its biogenesis. A recent yeast screen suggested that disulfiram (a well-known inhibitor of aldehyde dehydrogenase and a clinically used drug in the treatment of alcoholism) may inhibit CBS in a cell-based environment. However, prior studies have not observed any direct inhibition of CBS by disulfiram. We investigated the potential role of bioconversion of disulfiram to bis(N,N-diethyldithiocarbamate)-copper(II) complex (CuDDC) in the inhibitory effect of disulfiram on H2S production and assessed its effect in two human cell types with high CBS expression: HCT116 colon cancer cells and Down syndrome (DS) fibroblasts. METHODS: H2S production from recombinant human CBS, CSE and 3-MST was measured using the fluorescent H2S probe AzMC. Mouse liver homogenate (a rich source of CBS) was also employed to measure H2S biosynthesis. The interaction of copper with accessible protein cysteine residues was evaluated using the DTNB method. Cell proliferation and viability were measured using the BrdU and MTT methods. Cellular bioenergetics was evaluated by Extracellular Flux Analysis. RESULTS: While disulfiram did not exert any significant direct inhibitory effect on any of the H2S-producing enzymes, its metabolite, CuDDC was a potent inhibitor of CBS and CSE. The mode of its action is likely related to the complexed copper molecule. In cell-based systems, the effects of disulfiram were variable. In colon cancer cells, no significant effect of disulfiram was observed on H2S production or proliferation or viability. In contrast, in DS fibroblasts, disulfiram inhibited H2S production and improved proliferation and viability. Copper, on its own, failed to have any effects on either cell type, likely due to its low cell penetration. CuDDC inhibited H2S production in both cell types studied and exerted the functional effects that would be expected from a CBS inhibitor: inhibition of cell proliferation of cancer cells and a bell-shaped effect (stimulation of proliferation at low concentration and inhibition of these responses at higher concentration) in DS cells. Control experiments using a chemical H2S donor showed that, in addition to inhibiting CBS and CSE, part of the biological effects of CuDDC relates to a direct reaction with H2S, which occurs through its complexed copper. CONCLUSIONS: Disulfiram, via its metabolite CuDDC acts as an inhibitor of CBS and a scavenger of H2S, which, in turn, potently suppresses H2S levels in various cell types. Inhibition of H2S biosynthesis may explain some of the previously reported actions of disulfiram and CuDDC in vitro and in vivo. Disulfiram or CuDDC may be considered as potential agents for the experimental therapy of various pathophysiological conditions associated with H2S overproduction.

The Novel DA-CH3 Dual Incretin Restores Endoplasmic Reticulum Stress and Autophagy Impairments to Attenuate Alzheimer-Like Pathology and Cognitive Decrements in the APPSWE/PS1ΔE9 Mouse Model.

Alzheimer's disease (AD) afflicts more than 46.8 million people worldwide, with a newly diagnosed case every 3 seconds and no remission in the disease progression. The discovery of disease-modifying drugs is now on the summit of the neuropharmacological research priorities. The long-lasting derivatives of the insulinotropic incretin hormones-glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP)-have repeatedly been shown to cross the blood-brain barrier and counteract an array of deleterious effects across a range of experimental models of neuronal degeneration. Clinical trials for the efficacy of GLP-1 agonists in Alzheimer's and Parkinson's diseases have revealed beneficial effects of these anti-diabetic agents in halting neuronal degeneration progression. Herein, we examine whether the chronic treatment with the novel dual GLP-1/GIP receptor agonist DA-CH3 can restore the cognitive decline and AD-like cerebral pathology of the APPSWE/PS1ΔE9 mouse model at the age of 10 months old. We report that once-a-daily, eight-week intraperitoneal administration of 25 nmol/kg of the novel DA-CH3 dual-incretin analog rescues the spatial acquisition and memory impairments of this murine model that corresponds to the attenuation of the excessive plaque deposition, gliosis and synaptic damage in the APPSWE/PS1ΔE9 brain. The amelioration of the AD-related pathology reflects the resolution of the endoplasmic-reticulum stress and derailed autophagy that both lay downstream of the rectified Akt signaling. Collectively, our findings endorse the beneficial effects of the incretin-based therapeutic approaches for the neurotrophic support of the AD brain and for the first time associate the incretin-induced neuroprotection with the proteostasis machinery in vivo.

Liraglutide restores chronic ER stress, autophagy impairments and apoptotic signalling in SH-SY5Y cells.

Growing evidence suggests that agonists of glucagon-like peptide (GLP-1) receptor exert neuroprotective and neurorestorative effects across a range of experimental models of neuronal degeneration, and, recently, a pilot clinical trial of Liraglutide in Alzheimer's disease patients showed improvements in cerebral glucose consumption that signifies disease progression. However, the exact underlying mechanism of action remains unclear. Chronic endoplasmic reticulum (ER) stress has recently emerged as a mechanism for neuronal injury, rendering it a potent therapeutic target for acute and chronic neurodegenerative disorders. Here, we investigate the neuroprotective effects of Liraglutide along with the signalling network against prolong ER stress and autophagy impairments induced by the non-competitive inhibitor of sarco/ER Ca2+-ATPase, thapsigargin. We show that Liraglutide modulates the ER stress response and elicits ER proteostasis and autophagy machinery homeostasis in human SH-SY5Y neuroblastoma cell line. These effects correlate with resolution of hyper-activity of the antioxidant Nrf2 factor and restoration of the impaired cell viability and proliferation. Mechanistically, Liraglutide engages Akt and signal transducer and activator of transcription 3 (STAT3) signalling to favour adaptive responses and shift cell fate from apoptosis to survival under chronic stress conditions in SH-SY5Y cells.

Neuroprotective and cognitive enhancing effects of a multi-targeted food intervention in an animal model of neurodegeneration and depression.

Rising neurodegenerative and depressive disease prevalence combined with the lack of effective pharmaceutical treatments and dangerous side effects, has created an urgent need for the development of effective therapies. Considering that these disorders are multifactorial in origin, treatments designed to interfere at different mechanistic levels may be more effective than the traditional single-targeted pharmacological concepts. To that end, an experimental diet composed of zinc, melatonin, curcumin, piperine, eicosapentaenoic acid (EPA, 20:5, n-3), docosahexaenoic acid (DHA, 22:6, n-3), uridine, and choline was formulated. This diet was tested on the olfactory bulbectomized rat (OBX), an established animal model of depression and cognitive decline. The ingredients of the diet have been individually shown to attenuate glutamate excitoxicity, exert potent anti-oxidant/anti-inflammatory properties, and improve synaptogenesis; processes that all have been implicated in neurodegenerative diseases and in the cognitive deficits following OBX in rodents. Dietary treatment started 2 weeks before OBX surgery, continuing for 6 weeks in total. The diet attenuated OBX-induced cognitive and behavioral deficits, except long-term spatial memory. Ameliorating effects of the diet extended to the control animals. Furthermore, the experimental diet reduced hippocampal atrophy and decreased the peripheral immune activation in the OBX rats. The ameliorating effects of the diet on the OBX-induced changes were comparable to those of the NMDA receptor antagonist, memantine, a drug used for the management of Alzheimer's disease. This proof-of-concept study suggests that a diet, which simultaneously targets multiple disease etiologies, can prevent/impede the development of a neurodegenerative and depressive disorders and the concomitant cognitive deficits.