Neuroprotective effects of the PPARß/δ antagonist GSK0660 in in vitro and in vivo Parkinson's disease models.

BACKGROUND: The underlying mechanism of Parkinson's disease are still unidentified, but excitotoxicity, oxidative stress, and neuroinflammation are considered key actors. Proliferator activated receptors (PPARs) are transcription factors involved in the control of numerous pathways. Specifically, PPARß/δ is recognized as an oxidative stress sensor, and we have previously reported that it plays a detrimental role in neurodegeneration. METHODS: Basing on this concept, in this work, we tested the potential effects of a specific PPARß/δ antagonist (GSK0660) in an in vitro model of Parkinson's disease. Specifically, live-cell imaging, gene expression, Western blot, proteasome analyses, mitochondrial and bioenergetic studies were performed. Since we obtained promising results, we tested this antagonist in a 6-hydroxydopamine hemilesioned mouse model. In the animal model, behavioral tests, histological analysis, immunofluorescence and western blot of substantia nigra and striatum upon GSK0660 were assayed. RESULTS: Our findings suggested that PPARß/δ antagonist has neuroprotective potential due to neurotrophic support, anti-apoptotic and anti-oxidative effects paralleled to an amelioration of mitochondria and proteasome activity. These findings are strongly supported also by the siRNA results demonstrating that by silencing PPARß/δ a significative rescue of the dopaminergic neurons was obtained, thus indicating an involvement of PPARß/δ in PD's pathogenesis. Interestingly, in the animal model, GSK0660 treatment confirmed neuroprotective effects observed in the in vitro studies. Neuroprotective effects were highlighted by the behavioural performance and apomorphine rotation tests amelioration and the reduction of dopaminergic neuronal loss. These data were also confirmed by imaging and western blotting, indeed, the tested compound decreased astrogliosis and activated microglia, concomitant with an upregulation of neuroprotective pathways. CONCLUSIONS: In summary, PPARß/δ antagonist displayed neuroprotective activities against 6-hydroxydopamine detrimental effects both in vitro and in vivo models of Parkinson's disease, suggesting that it may represent a novel therapeutic approach for this disorder.

Differential Effects of Nonsteroidal Anti-Inflammatory Drugs in an In Vitro Model of Human Leaky Gut.

The intestinal barrier is the main contributor to gut homeostasis. Perturbations of the intestinal epithelium or supporting factors can lead to the development of intestinal hyperpermeability, termed "leaky gut". A leaky gut is characterized by loss of epithelial integrity and reduced function of the gut barrier, and is associated with prolonged use of Non-Steroidal Anti-Inflammatories. The harmful effect of NSAIDs on intestinal and gastric epithelial integrity is considered an adverse effect that is common to all drugs belonging to this class, and it is strictly dependent on NSAID properties to inhibit cyclo-oxygenase enzymes. However, different factors may affect the specific tolerability profile of different members of the same class. The present study aims to compare the effects of distinct classes of NSAIDs, such as ketoprofen (K), Ibuprofen (IBU), and their corresponding lysine (Lys) and, only for ibuprofen, arginine (Arg) salts, using an in vitro model of leaky gut. The results obtained showed inflammatory-induced oxidative stress responses, and related overloads of the ubiquitin-proteasome system (UPS) accompanied by protein oxidation and morphological changes to the intestinal barrier, many of these effects being counteracted by ketoprofen and ketoprofen lysin salt. In addition, this study reports for the first time a specific effect of R-Ketoprofen on the NFkB pathway that sheds new light on previously reported COX-independent effects, and that may account for the observed unexpected protective effect of K on stress-induced damage on the IEB.

Neurotrophic factor-based pharmacological approaches in neurological disorders.

Aging is a physiological event dependent on multiple pathways that are linked to lifespan and processes leading to cognitive decline. This process represents the major risk factor for aging-related diseases such as Alzheimer's disease, Parkinson's disease, and ischemic stroke. The incidence of all these pathologies increases exponentially with age. Research on aging biology has currently focused on elucidating molecular mechanisms leading to the development of those pathologies. Cognitive deficit and neurodegeneration, common features of aging-related pathologies, are related to the alteration of the activity and levels of neurotrophic factors, such as brain-derived neurotrophic factor, nerve growth factor, and glial cell-derived neurotrophic factor. For this reason, treatments that modulate neurotrophin levels have acquired a great deal of interest in preventing neurodegeneration and promoting neural regeneration in several neurological diseases. Those treatments include both the direct administration of neurotrophic factors and the induced expression with viral vectors, neurotrophins' binding with biomaterials or other molecules to increase their bioavailability but also cell-based therapies. Considering neurotrophins' crucial role in aging pathologies, here we discuss the involvement of several neurotrophic factors in the most common brain aging-related diseases and the most recent therapeutic approaches that provide direct and sustained neurotrophic support.

Neuroprotective effects of the PPARß/δ antagonist GSK0660 in in vitro and in vivo Parkinson's disease models

BACKGROUND: The underlying mechanism of Parkinson's disease are still unidentified, but excitotoxicity, oxidative stress, and neuroinflammation are considered key actors. Proliferator activated receptors (PPARs) are transcription factors involved in the control of numerous pathways. Specifically, PPARß/δ is recognized as an oxidative stress sensor, and we have previously reported that it plays a detrimental role in neurodegeneration. METHODS: Basing on this concept, in this work, we tested the potential effects of a specific PPARß/δ antagonist (GSK0660) in an in vitro model of Parkinson's disease. Specifically, live-cell imaging, gene expression, Western blot, proteasome analyses, mitochondrial and bioenergetic studies were performed. Since we obtained promising results, we tested this antagonist in a 6-hydroxydopamine hemilesioned mouse model. In the animal model, behavioral tests, histological analysis, immunofluorescence and western blot of substantia nigra and striatum upon GSK0660 were assayed. RESULTS: Our findings suggested that PPARß/δ antagonist has neuroprotective potential due to neurotrophic support, anti-apoptotic and anti-oxidative effects paralleled to an amelioration of mitochondria and proteasome activity. These findings are strongly supported also by the siRNA results demonstrating that by silencing PPARß/δ a significative rescue of the dopaminergic neurons was obtained, thus indicating an involvement of PPARß/δ in PD's pathogenesis. Interestingly, in the animal model, GSK0660 treatment confirmed neuroprotective effects observed in the in vitro studies. Neuroprotective effects were highlighted by the behavioural performance and apomorphine rotation tests amelioration and the reduction of dopaminergic neuronal loss. These data were also confirmed by imaging and western blotting, indeed, the tested compound decreased astrogliosis and activated microglia, concomitant with an upregulation of neuroprotective pathways. CONCLUSIONS: In summary, PPARß/δ antagonist displayed neuroprotective activities against 6-hydroxydopamine detrimental effects both in vitro and in vivo models of Parkinson's disease, suggesting that it may represent a novel therapeutic approach for this disorder.

The Influence of Dietary Supplementations on Neuropathic Pain.

Neuropathic pain is defined as pain caused by a lesion or disease of the somatosensory nervous system and affects 7-10% of the worldwide population. Neuropathic pain can be induced by the use of drugs, including taxanes, thus triggering chemotherapy-induced neuropathic pain or as consequence of metabolic disorders such as diabetes. Neuropathic pain is most often a chronic condition, and can be associated with anxiety and depression; thus, it negatively impacts quality of life. Several pharmacologic approaches exist; however, they can lead numerous adverse effects. From this perspective, the use of nutraceuticals and diet supplements can be helpful in relieve neuropathic pain and related symptoms. In this review, we discuss how diet can radically affect peripheral neuropathy, and we focus on the potential approaches to ameliorate this condition, such as the use of numerous nutritional supplements or probiotics.

Are We What We Eat? Impact of Diet on the Gut-Brain Axis in Parkinson's Disease.

Parkinson's disease is characterized by motor and non-motor symptoms, such as defects in the gut function, which may occur before the motor symptoms. To date, there are therapies that can improve these symptoms, but there is no cure to avoid the development or exacerbation of this disorder. Dysbiosis of gut microbiota could have a crucial role in the gut-brain axis, which is a bidirectional communication between the central nervous system and the enteric nervous system. Diet can affect the microbiota composition, impacting gut-brain axis functionality. Gut microbiome restoration through probiotics, prebiotics, synbiotics or other dietary means could have the potential to slow PD progression. In this review, we will discuss the influence of diet on the bidirectional communication between gut and brain, thus supporting the hypothesis that this disorder could begin in the gut. We also focus on how food-based therapies might then have an influence on PD and could ameliorate non-motor as well as motor symptoms.

S-Carboxymethyl Cysteine Protects against Oxidative Stress and Mitochondrial Impairment in a Parkinson's Disease In Vitro Model.

The mucolytic agent S-carboxymethylcysteine is widely used as an expectorant for the treatment of numerous respiratory disorders. The metabolic fate of S-carboxymethyl-L-cysteine is complex. Several clinical studies have demonstrated that the metabolism of this agent differs within the same individual, with sulfur oxygenated metabolites generated upon night-time administration. It has been indicated that this drug behaves like a free radical scavenger and that, in this regard, the sulfide is the active species with sulphoxide metabolites (already oxidized) being inactive. Consequently, a night-time consumption of the drug should be more effective upon daytime administration. Still, this diurnal variation in biotransformation (deactivation) is dependent on the genetic polymorphism on which relies the patient population capacities of S-carboxymethyl-L-cysteine sulphoxidation. It has been reported that those cohorts who are efficient sulfur oxidizers will generate inactive oxygenated metabolites. In contrast, those who have a relative deficiency in this mechanism will be subjected to the active sulfide for a more extended period. In this regard, it is noteworthy that 38-39% of Parkinson's disease patients belong to the poor sulphoxide cohort, being exposed to higher levels of active sulfide, the active antioxidant metabolite of S-carboxymethyl-L-cysteine. Parkinson's disease is a neurodegenerative disorder that affects predominately dopaminergic neurons. It has been demonstrated that oxidative stress and mitochondrial dysfunction play a crucial role in the degeneration of dopaminergic neurons. Based on this evidence, in this study, we evaluated the effects of S-carboxymethyl cysteine in an in vitro model of Parkinson's disease in protecting against oxidative stress injury. The data obtained suggested that an S-carboxymethylcysteine-enriched diet could be beneficial during aging to protect neurons from oxidative imbalance and mitochondrial dysfunction, thus preventing the progression of neurodegenerative processes.

Looking for In Vitro Models for Retinal Diseases.

Retina is a layered structure of the eye, composed of different cellular components working together to produce a complex visual output. Because of its important role in visual function, retinal pathologies commonly represent the main causes of visual injury and blindness in the industrialized world. It is important to develop in vitro models of retinal diseases to use them in first screenings before translating in in vivo experiments and clinics. For this reason, it is important to develop bidimensional (2D) models that are more suitable for drug screening and toxicological studies and tridimensional (3D) models, which can replicate physiological conditions, for investigating pathological mechanisms leading to visual loss. This review provides an overview of the most common retinal diseases, relating to in vivo models, with a specific focus on alternative 2D and 3D in vitro models that can replicate the different cellular and matrix components of retinal layers, as well as injury insults that induce retinal disease and loss of the visual function.

CXCR1/2 Inhibitor Ladarixin Ameliorates the Insulin Resistance of 3T3-L1 Adipocytes by Inhibiting Inflammation and Improving Insulin Signaling.

Type 2 diabetes mellitus is a severe public health issue worldwide. It displays a harmful effect on different organs as the eyes, kidneys and neural cells due to insulin resistance and high blood glucose concentrations. To date, the available treatments for this disorder remain limited. Several reports have correlated obesity with type 2 diabetes. Mainly, dysfunctional adipocytes and the regulation of high secretion of inflammatory cytokines are the crucial links between obesity and insulin resistance. Several clinical and epidemiological studies have also correlated the onset of type 2 diabetes with inflammation, which is now indicated as a new target for type 2 diabetes treatment. Thus, it appears essential to discover new drugs able to inhibit the secretion of proinflammatory adipocytokines in type 2 diabetes. Adipocytes produce inflammatory cytokines in response to inflammation or high glucose levels. Once activated by a specific ligand, CXCR1 and CXCR2 mediate some cytokines' effects by activating an intracellular signal cascade once activated by a specific ligand. Therefore, it is conceivable to hypothesize that a specific antagonist of these receptors may ameliorate type 2 diabetes and glucose metabolism. Herein, differentiated 3T3-L1-adipocytes were subjected to high glucose or inflammatory conditions or the combination of both and then treated with ladarixin, a CXCR1/2 inhibitor. The results obtained point towards the positive regulation by ladarixin on insulin sensitivity, glucose transporters GLUT1 and GLUT4, cytokine proteome profile and lipid metabolism, thus suggesting ladarixin as a potentially helpful treatment in type 2 diabetes mellitus and obesity.

L-Methionine Protects against Oxidative Stress and Mitochondrial Dysfunction in an In Vitro Model of Parkinson's Disease.

Methionine is an aliphatic, sulfur-containing, essential amino acid that has been demonstrated to have crucial roles in metabolism, innate immunity, and activation of endogenous antioxidant enzymes, including methionine sulfoxide reductase A/B and the biosynthesis of glutathione to counteract oxidative stress. Still, methionine restriction avoids altered methionine/transmethylation metabolism, thus reducing DNA damage and possibly avoiding neurodegenerative processes. In this study, we wanted to study the preventive effects of methionine in counteracting 6-hydroxydopamine (6-OHDA)-induced injury. In particular, we analyzed the protective effects of the amino acid L-methionine in an in vitro model of Parkinson's disease and dissected the underlying mechanisms compared to the known antioxidant taurine to gain insights into the potential of methionine treatment in slowing the progression of the disease by maintaining mitochondrial functionality. In addition, to ascribe the effects of methionine on mitochondria and oxidative stress, methionine sulfoxide was used in place of methionine. The data obtained suggested that an L-methionine-enriched diet could be beneficial during aging to protect neurons from oxidative imbalance and mitochondrial dysfunction, thus preventing the progression of neurodegenerative processes.

PPARα-Selective Antagonist GW6471 Inhibits Cell Growth in Breast Cancer Stem Cells Inducing Energy Imbalance and Metabolic Stress.

Breast cancer is the most frequent cancer and the second leading cause of death among women. Triple-negative breast cancer is the most aggressive subtype of breast cancer and is characterized by the absence of hormone receptors and human epithelial growth factor receptor 2. Cancer stem cells (CSCs) represent a small population of tumor cells showing a crucial role in tumor progression, metastasis, recurrence, and drug resistance. The presence of CSCs can explain the failure of conventional therapies to completely eradicate cancer. Thus, to overcome this limit, targeting CSCs may constitute a promising approach for breast cancer treatment, especially in the triple-negative form. To this purpose, we isolated and characterized breast cancer stem cells from a triple-negative breast cancer cell line, MDA-MB-231. The obtained mammospheres were then treated with the specific PPARα antagonist GW6471, after which, glucose, lipid metabolism, and invasiveness were analyzed. Notably, GW6471 reduced cancer stem cell viability, proliferation, and spheroid formation, leading to apoptosis and metabolic impairment. Overall, our findings suggest that GW6471 may be used as a potent adjuvant for gold standard therapies for triple-negative breast cancer, opening the possibility for preclinical and clinical trials for this class of compounds.

Neuroprotective potential of choline alfoscerate against ß-amyloid injury: Involvement of neurotrophic signals.

Alzheimer's disease represents the most prevalent neurodegeneration worldwide, clinically characterized by cognitive and memory impairment. New therapeutic approaches are extremely important to counteract this disorder. This research is focused on the potential use of choline alfoscerate in preventing neuronal death using in vitro models of Alzheimer's disease, representing the early stage of the disease, treated before or after the insult with glycerylphosphorylcholine. On the light of the results collected, we can postulate that choline alfoscerate, by the activation of the neurotrophin survival pathway, was able to counteract the detrimental effect of ß-amyloid in both in vitro models, reducing apoptotic cell death and preserving the neuronal morphology.

Effects of the probiotic formulation SLAB51 in in vitro and in vivo Parkinson's disease models.

Parkinson is a common neurodegenerative disorder, characterized by motor and non-motor symptoms, including abnormalities in the gut function, which may appear before the motor sign. To date, there are treatments that can help relieve Parkinson' disease (PD)-associated symptoms, but there is no cure to control the onset and progression of this disorder. Altered components of the gut could represent a key role in gut-brain axis, which is a bidirectional system between the central nervous system and the enteric nervous system. Diet can alter the microbiota composition, affecting gut-brain axis function. Gut microbiome restoration through selected probiotics' administration has been reported. In this study, we investigated the effects of the novel formulation SLAB51 in PD. Our findings indicate that this probiotic formulation can counteract the detrimental effect of 6-OHDA in vitro and in vivo models of PD. The results suggest that SLAB51 can be a promising candidate for the prevention or as coadjuvant treatment of PD.