Dysfunctional oxidative phosphorylation shunts branched-chain amino acid catabolism onto lipogenesis in skeletal muscle.

It is controversial whether mitochondrial dysfunction in skeletal muscle is the cause or consequence of metabolic disorders. Herein, we demonstrate that in vivo inhibition of mitochondrial ATP synthase in muscle alters whole-body lipid homeostasis. Mice with restrained mitochondrial ATP synthase activity presented intrafiber lipid droplets, dysregulation of acyl-glycerides, and higher visceral adipose tissue deposits, poising these animals to insulin resistance. This mitochondrial energy crisis increases lactate production, prevents fatty acid ß-oxidation, and forces the catabolism of branched-chain amino acids (BCAA) to provide acetyl-CoA for de novo lipid synthesis. In turn, muscle accumulation of acetyl-CoA leads to acetylation-dependent inhibition of mitochondrial respiratory complex II enhancing oxidative phosphorylation dysfunction which results in augmented ROS production. By screening 702 FDA-approved drugs, we identified edaravone as a potent mitochondrial antioxidant and enhancer. Edaravone administration restored ROS and lipid homeostasis in skeletal muscle and reinstated insulin sensitivity. Our results suggest that muscular mitochondrial perturbations are causative of metabolic disorders and that edaravone is a potential treatment for these diseases.

Generation of mitochondrial reactive oxygen species is controlled by ATPase inhibitory factor 1 and regulates cognition.

The mitochondrial ATP synthase emerges as key hub of cellular functions controlling the production of ATP, cellular signaling, and fate. It is regulated by the ATPase inhibitory factor 1 (IF1), which is highly abundant in neurons. Herein, we ablated or overexpressed IF1 in mouse neurons to show that IF1 dose defines the fraction of active/inactive enzyme in vivo, thereby controlling mitochondrial function and the production of mitochondrial reactive oxygen species (mtROS). Transcriptomic, proteomic, and metabolomic analyses indicate that IF1 dose regulates mitochondrial metabolism, synaptic function, and cognition. Ablation of IF1 impairs memory, whereas synaptic transmission and learning are enhanced by IF1 overexpression. Mechanistically, quenching the IF1-mediated increase in mtROS production in mice overexpressing IF1 reduces the increased synaptic transmission and obliterates the learning advantage afforded by the higher IF1 content. Overall, IF1 plays a key role in neuronal function by regulating the fraction of ATP synthase responsible for mitohormetic mtROS signaling.

R-Ras1 and R-Ras2 Expression in Anatomical Regions and Cell Types of the Central Nervous System.

Since the optic nerve is one of the most myelinated tracts in the central nervous system (CNS), many myelin diseases affect the visual system. In this sense, our laboratory has recently reported that the GTPases R-Ras1 and R-Ras2 are essential for oligodendrocyte survival and maturation. Hypomyelination produced by the absence of one or both proteins triggers axonal degeneration and loss of visual and motor function. However, little is known about R-Ras specificity and other possible roles that they could play in the CNS. In this work, we describe how a lack of R-Ras1 and/or R-Ras2 could not be compensated by increased expression of the closely related R-Ras3 or classical Ras. We further studied R-Ras1 and R-Ras2 expression within different CNS anatomical regions, finding that both were more abundant in less-myelinated regions, suggesting their expression in non-oligodendroglial cells. Finally, using confocal immunostaining colocalization, we report for the first time that R-Ras2 is specifically expressed in neurons. Neither microglia nor astrocytes expressed R-Ras1 or R-Ras2. These results open a new avenue for the study of neuronal R-Ras2's contribution to the process of myelination.

Absence of R-Ras1 and R-Ras2 causes mitochondrial alterations that trigger axonal degeneration in a hypomyelinating disease model.

Fast synaptic transmission in vertebrates is critically dependent on myelin for insulation and metabolic support. Myelin is produced by oligodendrocytes (OLs) that maintain multilayered membrane compartments that wrap around axonal fibers. Alterations in myelination can therefore lead to severe pathologies such as multiple sclerosis. Given that hypomyelination disorders have complex etiologies, reproducing clinical symptoms of myelin diseases from a neurological perspective in animal models has been difficult. We recently reported that R-Ras1-/- and/or R-Ras2-/- mice, which lack GTPases essential for OL survival and differentiation processes, present different degrees of hypomyelination in the central nervous system with a compounded hypomyelination in double knockout (DKO) mice. Here, we discovered that the loss of R-Ras1 and/or R-Ras2 function is associated with aberrant myelinated axons with increased numbers of mitochondria, and a disrupted mitochondrial respiration that leads to increased reactive oxygen species levels. Consequently, aberrant myelinated axons are thinner with cytoskeletal phosphorylation patterns typical of axonal degeneration processes, characteristic of myelin diseases. Although we observed different levels of hypomyelination in a single mutant mouse, the combined loss of function in DKO mice lead to a compromised axonal integrity, triggering the loss of visual function. Our findings demonstrate that the loss of R-Ras function reproduces several characteristics of hypomyelinating diseases, and we therefore propose that R-Ras1-/- and R-Ras2-/- neurological models are valuable approaches for the study of these myelin pathologies.

In vivo inhibition of the mitochondrial H+-ATP synthase in neurons promotes metabolic preconditioning.

A key transducer in energy conservation and signaling cell death is the mitochondrial H(+)-ATP synthase. The expression of the ATPase inhibitory factor 1 (IF1) is a strategy used by cancer cells to inhibit the activity of the H(+)-ATP synthase to generate a ROS signal that switches on cellular programs of survival. We have generated a mouse model expressing a mutant of human IF1 in brain neurons to assess the role of the H(+)-ATP synthase in cell death in vivo. The expression of hIF1 inhibits the activity of oxidative phosphorylation and mediates the shift of neurons to an enhanced aerobic glycolysis. Metabolic reprogramming induces brain preconditioning affording protection against quinolinic acid-induced excitotoxicity. Mechanistically, preconditioning involves the activation of the Akt/p70S6K and PARP repair pathways and Bcl-xL protection from cell death. Overall, our findings provide the first in vivo evidence highlighting the H(+)-ATP synthase as a target to prevent neuronal cell death.

Evidence that meningeal mast cells can worsen stroke pathology in mice.

Stroke is the leading cause of adult disability and the fourth most common cause of death in the United States. Inflammation is thought to play an important role in stroke pathology, but the factors that promote inflammation in this setting remain to be fully defined. An understudied but important factor is the role of meningeal-located immune cells in modulating brain pathology. Although different immune cells traffic through meningeal vessels en route to the brain, mature mast cells do not circulate but are resident in the meninges. With the use of genetic and cell transfer approaches in mice, we identified evidence that meningeal mast cells can importantly contribute to the key features of stroke pathology, including infiltration of granulocytes and activated macrophages, brain swelling, and infarct size. We also obtained evidence that two mast cell-derived products, interleukin-6 and, to a lesser extent, chemokine (C-C motif) ligand 7, can contribute to stroke pathology. These findings indicate a novel role for mast cells in the meninges, the membranes that envelop the brain, as potential gatekeepers for modulating brain inflammation and pathology after stroke.

Systemic augmentation of alphaB-crystallin provides therapeutic benefit twelve hours post-stroke onset via immune modulation.

Tissue plasminogen activator is the only treatment option for stroke victims; however, it has to be administered within 4.5 h after symptom onset, making its use very limited. This report describes a unique target for effective treatment of stroke, even 12 h after onset, by the administration of αB-crystallin (Cryab), an endogenous immunomodulatory neuroprotectant. In Cryab(-/-) mice, there was increased lesion size and diminished neurologic function after stroke compared with wild-type mice. Increased plasma Cryab was detected after experimental stroke in mice and after stroke in human patients. Administration of Cryab even 12 h after experimental stroke reduced both stroke volume and inflammatory cytokines associated with stroke pathology. Cryab is an endogenous anti-inflammatory and neuroprotectant molecule produced after stroke, whose beneficial properties can be augmented when administered therapeutically after stroke.

The therapeutic use of clonal neural stem cells in experimental Parkinson´s disease.

BACKGROUND: Parkinson´s disease (PD), the second most common neurodegenerative disease in the world, is characterized by the death or impairment of dopaminergic neurons (DAn) in the substantia nigra pars compacta and dopamine depletion in the striatum. Currently, there is no cure for PD, and treatments only help to reduce the symptoms of the disease, and do not repair or replace the DAn damaged or lost in PD. Cell replacement therapy (CRT) seeks to relieve both pathological and symptomatic PD manifestations and has been shown to have beneficial effects in experimental PD models as well as in PD patients, but an apt cell line to be used in the treatment of PD has yet to be established. The purpose of this study was to examine the effects of the transplantation of hVM1 clone 32 cells, a bankable line of human neural stem cells (hNSCs), in a PD mouse model at four months post-transplant. METHODS: Adult (five month-old) C57BL/6JRccHsd male mice were injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and subsequently transplanted with hVM1 clone 32 cells, or buffer, in the left striatum. Four months post-transplant, behavioral effects were explored using the open field and paw print tests, and histological analyses were performed. RESULTS: Transplantation of hVM1 clone 32 cells rescued dopaminergic nigrostriatal populations in adult Parkinsonian mice. Motor and neurological deterioration were observed in buffer-treated mice, the latter of which had a tendency to improve in hNSC-transplanted mice. Detection of mast cell migration to the superficial cervical lymph nodes in cell-transplanted mice denoted a peripheral effect. Transplantation of hNSCs also rescued neuroblast neurogenesis in the subgranular zone, which was correlated with dopaminergic recovery and is indicative of local recovery mechanisms. CONCLUSIONS: In this proof-of-concept study, the transplantation of hVM1 clone 32 cells provided neuroprotection in adult Parkinsonian mice by restoring the dopaminergic nigrostriatal pathway and hippocampal neurogenesis, demonstrating the efficacy of cell replacement therapy as a treatment for PD.

Transplanted stem cell-secreted vascular endothelial growth factor effects poststroke recovery, inflammation, and vascular repair.

Cell transplantation offers a novel therapeutic strategy for stroke; however, how transplanted cells function in vivo is poorly understood. We show for the first time that after subacute transplantation into the ischemic brain of human central nervous system stem cells grown as neurospheres (hCNS-SCns), the stem cell-secreted factor, human vascular endothelial growth factor (hVEGF), is necessary for cell-induced functional recovery. We correlate this functional recovery to hVEGF-induced effects on the host brain including multiple facets of vascular repair and its unexpected suppression of the inflammatory response. We found that transplanted hCNS-SCns affected multiple parameters in the brain with different kinetics: early improvement in blood-brain barrier integrity and suppression of inflammation was followed by a delayed spatiotemporal regulated increase in neovascularization. These events coincided with a bimodal pattern of functional recovery, with, an early recovery independent of neovascularization, and a delayed hVEGF-dependent recovery coincident with neovascularization. Therefore, cell transplantation therapy offers an exciting multimodal strategy for brain repair in stroke and potentially other disorders with a vascular or inflammatory component.

Human neural stem cells enhance structural plasticity and axonal transport in the ischaemic brain.

Stem cell transplantation promises new hope for the treatment of stroke although significant questions remain about how the grafted cells elicit their effects. One hypothesis is that transplanted stem cells enhance endogenous repair mechanisms activated after cerebral ischaemia. Recognizing that bilateral reorganization of surviving circuits is associated with recovery after stroke, we investigated the ability of transplanted human neural progenitor cells to enhance this structural plasticity. Our results show the first evidence that human neural progenitor cell treatment can significantly increase dendritic plasticity in both the ipsi- and contralesional cortex and this coincides with stem cell-induced functional recovery. Moreover, stem cell-grafted rats demonstrated increased corticocortical, corticostriatal, corticothalamic and corticospinal axonal rewiring from the contralesional side; with the transcallosal and corticospinal axonal sprouting correlating with functional recovery. Furthermore, we demonstrate that axonal transport, which is critical for both proper axonal function and axonal sprouting, is inhibited by stroke and that this is rescued by the stem cell treatment, thus identifying another novel potential mechanism of action of transplanted cells. Finally, we established in vitro co-culture assays in which these stem cells mimicked the effects observed in vivo. Through immunodepletion studies, we identified vascular endothelial growth factor, thrombospondins 1 and 2, and slit as mediators partially responsible for stem cell-induced effects on dendritic sprouting, axonal plasticity and axonal transport in vitro. Thus, we postulate that human neural progenitor cells aid recovery after stroke through secretion of factors that enhance brain repair and plasticity.

Chronic inhibition of the mitochondrial ATP synthase in skeletal muscle triggers sarcoplasmic reticulum distress and tubular aggregates.

Tubular aggregates (TA) are honeycomb-like arrays of sarcoplasmic-reticulum (SR) tubules affecting aged glycolytic fibers of male individuals and inducing severe sarcomere disorganization and muscular pain. TA develop in skeletal muscle from Tubular Aggregate Myopathy (TAM) patients as well as in other disorders including endocrine syndromes, diabetes, and ageing, being their primary cause unknown. Nowadays, there is no cure for TA. Intriguingly, both hypoxia and calcium dyshomeostasis prompt TA formation, pointing to a possible role for mitochondria in their setting. However, a functional link between mitochondrial dysfunctions and TA remains unknown. Herein, we investigate the alteration in muscle-proteome of TAM patients, the molecular mechanism of TA onset and a potential therapy in a preclinical mouse model of the disease. We show that in vivo chronic inhibition of the mitochondrial ATP synthase in muscle causes TA. Upon long-term restrained oxidative phosphorylation (OXPHOS), oxidative soleus experiments a metabolic and structural switch towards glycolytic fibers, increases mitochondrial fission, and activates mitophagy to recycle damaged mitochondria. TA result from the overresponse of the fission controller DRP1, that upregulates the Store-Operate-Calcium-Entry and increases the mitochondria-SR interaction in a futile attempt to buffer calcium overloads upon prolonged OXPHOS inhibition. Accordingly, hypoxic muscles cultured ex vivo show an increase in mitochondria/SR contact sites and autophagic/mitophagic zones, where TA clusters grow around defective mitochondria. Moreover, hypoxia triggered a stronger TA formation upon ATP synthase inhibition, and this effect was reduced by the DRP1 inhibitor mDIVI. Remarkably, the muscle proteome of TAM patients displays similar alterations in mitochondrial dynamics and in ATP synthase contents. In vivo edaravone treatment in mice with restrained OXPHOS restored a healthy phenotype by prompting mitogenesis and mitochondrial fusion. Altogether, our data provide a functional link between the ATP synthase/DRP1 axis and the setting of TA, and repurpose edaravone as a possible treatment for TA-associated disorders.

Multifactoriality of Parkinson's Disease as Explored Through Human Neural Stem Cells and Their Transplantation in Middle-Aged Parkinsonian Mice.

Parkinson's disease (PD) is an age-associated neurodegenerative disorder for which there is currently no cure. Cell replacement therapy is a potential treatment for PD; however, this therapy has more clinically beneficial outcomes in younger patients with less advanced PD. In this study, hVM1 clone 32 cells, a line of human neural stem cells, were characterized and subsequently transplanted in middle-aged Parkinsonian mice in order to examine cell replacement therapy as a treatment for PD. In vitro analyses revealed that these cells express standard dopamine-centered markers as well as others associated with mitochondrial and peroxisome function, as well as glucose and lipid metabolism. Four months after the transplantation of the hVM1 clone 32 cells, striatal expression of tyrosine hydroxylase was minimally reduced in all Parkinsonian mice but that of dopamine transporter was decreased to a greater extent in buffer compared to cell-treated mice. Behavioral tests showed marked differences between experimental groups, and cell transplant improved hyperactivity and gait alterations, while in the striatum, astroglial populations were increased in all groups due to age and a higher amount of microglia were found in Parkinsonian mice. In the motor cortex, nonphosphorylated neurofilament heavy was increased in all Parkinsonian mice. Overall, these findings demonstrate that hVM1 clone 32 cell transplant prevented motor and non-motor impairments and that PD is a complex disorder with many influencing factors, thus reinforcing the idea of novel targets for PD treatment that tend to be focused on dopamine and nigrostriatal damage.

Next generation human brain models: engineered flat brain organoids featuring gyrification.

Brain organoids are considered to be a highly promising in vitro model for the study of the human brain and, despite their various shortcomings, have already been used widely in neurobiological studies. Especially for drug screening applications, a highly reproducible protocol with simple tissue culture steps and consistent output, is required. Here we present an engineering approach that addresses several existing shortcomings of brain organoids. By culturing brain organoids with a polycaprolactone scaffold, we were able to modify their shape into a flat morphology. Engineered flat brain organoids (efBOs) possess advantageous diffusion conditions and thus their tissue is better supplied with oxygen and nutrients, preventing the formation of a necrotic tissue core. Moreover, the efBO protocol is highly simplified and allows to customize the organoid size directly from the start. By seeding cells onto 12 by 12 mm scaffolds, the brain organoid size can be significantly increased. In addition, we were able to observe folding reminiscent of gyrification around day 20, which was self-generated by the tissue. To our knowledge, this is the first study that reports intrinsically caused gyrification of neuronal tissue in vitro. We consider our efBO protocol as a next step towards the generation of a stable and reliable human brain model for drug screening applications and spatial patterning experiments.

Synthesis of lipoxin A4 by 5-lipoxygenase mediates PPARgamma-dependent, neuroprotective effects of rosiglitazone in experimental stroke.

Peroxisome proliferator-activated receptors gamma (PPARgamma) are nuclear receptors with essential roles as transcriptional regulators of glucose and lipid homeostasis. PPARgamma are also potent anti-inflammatory receptors, a property that contributes to the neuroprotective effects of PPARgamma agonists in experimental stroke. The mechanism of these beneficial actions, however, is not fully elucidated. Therefore, we have explored further the actions of the PPARgamma agonist rosiglitazone in experimental stroke induced by permanent middle cerebral artery occlusion (MCAO) in rodents. Rosiglitazone induced brain 5-lipoxygenase (5-LO) expression in ischemic rat brain, concomitantly with neuroprotection. Rosiglitazone also increased cerebral lipoxin A(4) (LXA(4)) levels and inhibited MCAO-induced production of leukotriene B4 (LTB(4)). Furthermore, pharmacological inhibition and/or genetic deletion of 5-LO inhibited rosiglitazone-induced neuroprotection and downregulation of inflammatory gene expression, LXA(4) synthesis and PPARgamma transcriptional activity in rodents. Finally, LXA(4) caused neuroprotection, which was partly inhibited by the PPARgamma antagonist T0070907, and increased PPARgamma transcriptional activity in isolated nuclei, showing for the first time that LXA(4) has PPARgamma agonistic actions. Altogether, our data illustrate that some effects of rosiglitazone are attributable to de novo synthesis of 5-LO, able to induce a switch from the synthesis of proinflammatory LTB(4) to the synthesis of the proresolving LXA(4). Our study suggests novel lines of study such as the interest of lipoxin-like anti-inflammatory drugs or the use of these molecules as prognostic and/or diagnostic markers for pathologies in which inflammation is involved, such as stroke.

Pyrolytic Carbon Nanograss Enhances Neurogenesis and Dopaminergic Differentiation of Human Midbrain Neural Stem Cells.

Advancements in research on the interaction of human neural stem cells (hNSCs) with nanotopographies and biomaterials are enhancing the ability to influence cell migration, proliferation, gene expression, and tailored differentiation toward desired phenotypes. Here, the fabrication of pyrolytic carbon nanograss (CNG) nanotopographies is reported and demonstrated that these can be employed as cell substrates boosting hNSCs differentiation into dopaminergic neurons (DAn), a long-time pursued goal in regenerative medicine based on cell replacement. In the near future, such structures can play a crucial role in the near future for stem-cell based cell replacement therapy (CRT) and bio-implants for Parkinson's disease (PD). The unique combination of randomly distributed nanograss topographies and biocompatible pyrolytic carbon material is optimized to provide suitable mechano-material cues for hNSCs adhesion, division, and DAn differentiation of midbrain hNSCs. The results show that in the presence of the biocoating poly-L-lysine (PLL), the CNG enhances hNSCs neurogenesis up to 2.3-fold and DAn differentiation up to 3.5-fold. Moreover, for the first time, consistent evidence is provided, that CNGs without any PLL coating are not only supporting cell survival but also lead to significantly enhanced neurogenesis and promote hNSCs to acquire dopaminergic phenotype compared to PLL coated topographies.

Modulation of Monoaminergic Systems by Antidepressants in the Frontal Cortex of Rats After Chronic Mild Stress Exposure.

The standard pharmacological treatment of the major depressive disorder (MDD) is still grounded in a monoaminergic approach. Consequently, antidepressant treatments pursue to heighten serotonergic and noradrenergic neurotransmissions. Thus, the aim of this study was to assess the impact of exposure to a well-characterized animal model, the chronic mild stress (CMS) on serotonin (5-HT) and noradrenaline (NE) levels, and reuptake transporters and receptors in the frontal cortex (FC) of CMS-exposed rats. Moreover, considering the diverse pharmacological profiles of existing antidepressants and the large number of patients not responding to treatments, we have investigated whether generally utilized antidepressants can modulate their expression. Male Wistar rats were exposed to CMS and some of them treated with desipramine, escitalopram, or duloxetine. Possible changes in the described monoaminergic neurotransmission elements were evaluated. CMS induced differences in the expression of reuptake transporters and receptors involved in the monoaminergic neurotransmission pointing towards the weakening of their signaling. CMS antidepressant-treated rats showed an improvement of the monoaminergic tone, being desipramine and duloxetine more influential than escitalopram over noradrenergic elements and having the three antidepressant-tested effects on serotonergic transmission. In summary, there are molecular alterations on the monoaminergic neurotransmission in FC induced by CMS exposure. Besides, antidepressant treatments modulate the elements of these neurotransmission systems differentially.

Ischemic preconditioning reveals that GLT1/EAAT2 glutamate transporter is a novel PPARgamma target gene involved in neuroprotection.

Excessive levels of extracellular glutamate in the nervous system are excitotoxic and lead to neuronal death. Glutamate transport, mainly by glutamate transporter GLT1/EAAT2, is the only mechanism for maintaining extracellular glutamate concentrations below excitotoxic levels in the central nervous system. We recently showed that neuroprotection after experimental ischemic preconditioning (IPC) involves, at least partly, the upregulation of the GLT1/EAAT2 glutamate transporter in astrocytes, but the mechanisms were unknown. Thus, we decided to explore whether activation of the nuclear receptor peroxisome proliferator-activated receptor (PPAR) gamma, known for its antidiabetic and antiinflammatory properties, is involved in glutamate transport. First, we found that the PPARgamma antagonist T0070907 inhibits both IPC-induced tolerance and reduction of glutamate release after lethal oxygen-glucose deprivation (OGD) (70.1%+/-3.4% versus 97.7%+/-5.2% of OGD-induced lactate dehydrogenase (LDH) release and 61.8%+/-5.9% versus 85.9%+/-7.9% of OGD-induced glutamate release in IPC and IPC+T0070907 1 mumol/L, respectively, n=6 to 12, P<0.05), as well as IPC-induced astrocytic GLT-1 overexpression. IPC also caused an increase in nuclear PPARgamma transcriptional activity in neurons and astrocytes (122.1%+/-8.1% and 158.6%+/-22.6% of control PPARgamma transcriptional activity, n=6, P<0.05). Second, the PPARgamma agonist rosiglitazone increased both GLT-1/EAAT2 mRNA and protein expression and [(3)H]glutamate uptake, and reduced OGD-induced cell death and glutamate release (76.3%+/-7.9% and 65.5%+/-15.1% of OGD-induced LDH and glutamate release in rosiglitazone 1 mumol/l, respectively, n=6 to 12, P<0.05). Finally, we have identified six putative PPAR response elements (PPREs) in the GLT1/EAAT2 promoter and, consistently, rosiglitazone increased fourfold GLT1/EAAT2 promoter activity. All these data show that the GLT1/EAAT2 glutamate transporter is a target gene of PPARgamma leading to neuroprotection by increasing glutamate uptake.

Rosiglitazone and 15-deoxy-Delta12,14-prostaglandin J2 cause potent neuroprotection after experimental stroke through noncompletely overlapping mechanisms.

Stroke triggers an inflammatory cascade which contributes to a delayed cerebral damage, thus implying that antiinflammatory strategies might be useful in the treatment of acute ischaemic stroke. Since two unrelated peroxisome proliferator-activated receptor-gamma (PPARgamma) agonists, the thiazolidinedione rosiglitazone (RSG) and the cyclopentenone prostaglandin 15-deoxy-Delta(12,14)-prostaglandin J2 (15d-PGJ2), have been shown to possess antiinflammatory properties, we have tested their neuroprotective effects in experimental stroke. Rosiglitazone or 15d-PGJ2 were administered to rats 10 mins or 2 h after permanent middle cerebral artery occlusion (MCAO). Stroke outcome was evaluated by determination of infarct volume and assessment of neurological scores. Brains were collected for protein expression, gene array analyses and gene shift assays. Our results show that both compounds decrease MCAO-induced infarct size and improve neurological scores. At late times, the two compounds converge in the inhibition of MCAO-induced brain expression of inducible NO synthase and the matrix metalloproteinase 9. Interestingly, at early times, complementary DNA microarrays and gene shift assays show that different mechanisms are recruited. Analysis of early nuclear p65 and late cytosolic IkappaBalpha protein levels shows that both compounds inhibit nuclear factor-kappaB signalling, although at different levels. All these results suggest both PPARgamma-dependent and independent pathways, and might be useful to design both therapeutic strategies and prognostic markers for stroke.