Anti-oxidative and anti-neuroinflammatory role of Necrostatin-1s and docosahexaenoic acid in RIP-1-mediated neurotoxicity in MPTP-induced Parkinson's disease model.

Parkinson's disease (PD) is a neuromuscular ailment that affects people in their later years and causes both motor and non-motor deficits. Receptor-interacting protein-1 (RIP-1) is a critical participant in necroptotic cell death, possibly through an oxidant-antioxidant imbalance and cytokine cascade activation in PD pathogenesis. The present study examined the role of RIP-1-mediated necroptosis and neuroinflammation in the MPTP-induced PD mouse model, as well as their protection by Necrostatin-1s (an RIP signalling inhibitor), antioxidant DHA and their functional interaction. BALB/c mice were given acute MPTP therapy (4 injections of 15 mg/kg i.p. at 2-h intervals) on day 1. After MPTP intoxication, Necrostatin-1s (Nec-1s; 8 mg/kg/day, i.p.) and DHA (300 mg/kg/day, p.o.) treatments were given once daily for 7 days. The Nec-1s treatment prevented MPTP-induced behavioural, biochemical and neurochemical alterations, and the addition of DHA increases Nec-1s' neuroprotective impact. In addition, Nec-1s and DHA significantly improve the survival of TH-positive dopaminergic neurons and lower expression levels of the inflammatory cytokines, IL-1ß and TNF-α. Furthermore, Nec-1s dramatically reduced RIP-1 expression, whereas DHA had little effect. Our research raises the possibility that neuroinflammatory signalling and acute MPTP-induced necroptosis are both mediated by TNFR1-driven RIP-1 activity. In this study, RIP-1 ablation through Nec-1s and the addition of DHA showed a reduction in the levels of pro-inflammatory and oxidative markers, as well as protection from MPTP-driven dopaminergic degeneration and neurobehavioural changes, suggesting potential therapeutic applications. For a better understanding, additional research about the mechanism(s) behind Nec-1s and DHA is required.

Effects of mangiferin and its combination with nNOS inhibitor 7-nitro-indazole (7-NI) in 6-hydroxydopamine (6-OHDA) lesioned Parkinson's disease rats.

Nitric oxide (NO), generated by nitric oxide synthase enzymes (NOS), has an important role in maintaining synapse plasticity, neuro-modulation, and other physiological functions in the brain. NO thus generated also has a key role in formation of reactive oxygen and reactive nitrite species and subsequent neuronal damage due to sustained oxidative stress. Due to its property of ROS and RNOS generation, NO plays a significant role in Parkinson's disease (PD) pathogenesis. Therefore, we evaluated the effect of mangiferin alone and in combination with nNOS inhibitor 7-nitro-indazole (7-NI) in 6-OHDA lesioned rats. Male Wistar rats weighing 200-250 g (n = 8/group) were used in the study. Stereotactic surgeries of rats were done to induce 6-OHDA lesioning in rats. Then, treatment with mangiferin alone and in combination with 7-NI 10 mg/kg was done from days 14 to 42 for 28 days. On day 42, rats were subjected to behavioral studies, and their brains were taken out after euthanasia to perform biochemical and molecular studies. Treatment with mangiferin and 7-NI significantly increases locomotor parameters in 6-OHDA lesioned rats. Treatment with mangiferin 45 µg and 7-NI 10 mg/kg alone and in combination significantly reduces oxidative stress along with decrease in concentration of pro-inflammatory cytokines, cyclooxygenase 2, total nitrite (NOx) and FOS B concentration. Results of this study suggest that treatment with 7-NI 10 mg/kg further enhances anti-inflammatory and anti-parkinsonism activity of mangiferin owing to its property of inhibiting nNOS mediated FOS B signaling and thereby inhibiting mRNA formation of TNF-α and IL-6.

Pharmacological, Biochemical and Immunological Studies on Protective Effect of Mangiferin in 6-Hydroxydopamine (6-OHDA)-Induced Parkinson's Disease in Rats.

Background: Parkinson's disease is a neurodegenerative disorder and is marked by inflammation and death of neurons in the striatum region of the midbrain. It has been reported that expression of NF-κB increases during Parkinson's disease, which promotes oxidative stress, stimulates release of proinflammatory cytokines, and induces expression of nitric oxide. Therefore, in this study, we have used mangiferin a specific NF-κB inhibitor. Mangiferin is a polyphenolic compound traditionally used for its antioxidant and anti-inflammatory properties. Methods: The study utilized male Wistar rats weighing 200-250 g (56 rats; n = 8/group). On day "0," stereotaxic surgery of rats was done to induce 6-hydroxydopamine lesioning in rats. Coordinates for substantia nigra were anteroposterior-2 mm, mediolateral-5 mm and dorsoventral-8.2 mm. After 14 days, those rats which show at least 210 contralateral rotations after administration of apomorphine (0.5 mg/kg S.C.) were selected for the study and were given treatment for 28 days. On day 28 of treatment, rats were subjected to behavioral studies to evaluate the effect of mangiferin and their brains were taken out after euthanasia to perform biochemical, molecular and immunological studies. Results: Treatment with mangiferin significantly improves the key parameters of locomotor activity and oxidative stress and reduces the parameters of inflammatory stress. Also, the activity of caspases was reduced. Significant decrease in activity of both cyclooxygenase 1 and 2 was also observed. Maximum improvement in all parameters was observed in rats treated with grouping of mangiferin 45 µg/kg and levodopa 10 mg/kg. Treatment with levodopa alone has no significant effect on biochemical and molecular parameters though it significantly improves behavioral parameters. Conclusion: Current treatment of Parkinson's disease does not target progression of Parkinson's disease. Results of this study suggest that mangiferin has protective effect in hemi-Parkinsonian rats. Therefore, the combination therapy of mangiferin and levodopa can be helpful in management of Parkinson's disease.

Pharmacological and biochemical studies on protective effects of mangiferin and its interaction with nitric oxide (NO) modulators in adjuvant-induced changes in arthritic parameters, inflammatory, and oxidative biomarkers in rats.

Current study was designed to evaluate protective effect of mangiferin and its interaction with low dose of nitric oxide (NO) modulators in complete Freund's adjuvant (CFA) inoculated rats. Male wistar rats (200-300 g, n = 8 per group) were used in the study. On day ''0'' of study arthritis was induced in rats by injecting 0.2 ml CFA in sub-planter region of right hind paw of animals. Treatment with methotrexate (5 mg/kg), mangiferin (10-30 mg/kg) alone and in combination with NO modulators was given (i.p.) from days 14 to 28. After 28 days, blood and joint synovial fluid was collected for biochemical analysis and rat paws were excised to estimate MDA and SOD in tissue (paw) homogenates. CFA inoculation significantly increases (1) arthritic index, (2) ankle diameter, (3) paw volume, and (4) serum TNF-α, IL-6, IL-1ß, and synovial TNF-α levels (p < 0.001). The serum Th1 (IFN-γ) and Th2 (IL-4) cytokine levels, MDA levels in rat paw tissue homogenates and serum NF-κB levels were also found significantly increased. Significant decrease in serum IL-10 levels and SOD activity was found after CFA inoculation. These CFA-induced arthritic changes, cytokine profile, and oxidative stress markers were significantly reversed by mangiferin (10-30 mg/kg) treatment alone and in combination with L-arginine and L-NAME nitric oxide modulators (p < 0.05). Treatment with methotrexate (5 mg/kg) also significantly reversed these adjuvant changes (p < 0.05). However, effect of methotrexate was less marked as compared to mangiferin (30 mg/kg) alone and in combination with L-NAME (10 mg/kg), but was comparable or slightly better than mangiferin (10 and 20 mg/kg). Thus, on the basis of our findings, we can suggest that interaction of mangiferin with nitric oxide modulators may have therapeutic value for chronic inflammatory disease such as RA.

The potential role of neuroinflammation and transcription factors in Parkinson disease.

Parkinson disease (PD) is a neurodegenerative disorder characterized by dopaminergic neurons affected by inflammatory processes. Post-mortem analyses of brain and cerebrospinal fluid from PD patients show the accumulation of proinflammatory cytokines, confirming an ongoing neuroinflammation in the affected brain regions. These inflammatory mediators may activate transcription factors-notably nuclear factor κB, Ying-Yang 1 (YY1), fibroblast growth factor 20 (FGF20), and mammalian target of rapamycin (mTOR)-which then regulate downstream signaling pathways that in turn promote death of dopaminergic neurons through death domain-containing receptors. Dopaminergic neurons are vulnerable to oxidative stress and inflammatory attack. An increased level of inducible nitric oxide synthase observed in the substantia nigra and striatum of PD patients suggests that both cytokine-and chemokine-induced toxicity and inflammation lead to oxidative stress that contributes to degeneration of dopaminergic neurons and to disease progression. Lipopolysaccharide activation of microglia in the proximity of dopaminergic neurons in the substantia nigra causes their degeneration, and this appears to be a selective vulnerability of dopaminergic neurons to inflammation. In this review, we will look at the role of various transcription factors and signaling pathways in the development of PD.

La Enfermedad de Parkinson (EP) es un trastorno neurodegenerativo caracterizado por procesos inflamatorios en neuronas dopaminérgicas. El análisis post-mortem de cerebro y líquido céfalo raquídeo de pacientes con EP muestra la acumulación de citoquinas proinflamatorias, lo que confirma un proceso neuroinflamatorio en las regiones cerebrales afectadas. Estos mediadores inflamatorios pueden activar factores de transmisión­en especial el factor nuclear κB, el Ying-Yang 1 (YY1), el factor de crecimiento de fibroblastos 20 (FGF20) y un blanco de rapamicina en los mamíferos (mTOR)­los que regulan las vías de señales descendentes y a la vez promueven la muerte de neuronas dopaminérgicas, a través de receptores que tienen un dominio de muerte. Las neuronas dopaminérgicas son vulnerables al estrés oxidativo y al ataque inflamatorio. En la sustancia nigra y el estriado de pacientes con EP se ha observado un aumento del nivel de sintetasa de óxido nítrico inducible, lo que sugiere que tanto la inflamación como la toxicidad inducidas por citoquinas y quimioquinas llevan al estrés oxidativo, lo que contribuye a la degeneración de las neuronas dopaminérgicas y al avance de la enfermedad. La activación de lipopolisacáridos de la microglía, en la proximidad de las neuronas dopaminérgicas en la sustancia nigra, provoca su degeneración y esto parece ser una vulnerabilidad selectiva de las neuronas dopaminérgicas a la inflamación. En este artículo se revisa el papel de varios factores de transcripción y vías de señales en el desarrollo de la EP.

La maladie de Parkinson (MP) est un trouble dégéneratif caractérisé par l'atteinte des neurones dopaminergiques par des processus inflammatoires. Des analyses post-mortem du cerveau et du liquide céphalo-rachidien de patients parkinsoniens montrent l'accumulation de cytokines pro-inflammatoires, confirmant la présence d'une neuro-inflammation dans les régions cérébrales affectées. Ces médiateurs inflammatoires activent des facteurs de transcription, en particulier le facteur nucléaire κB, le Ying-Yang 1 (YY1), le facteur 20 de croissance du fibroblaste (FGF20) et mTOR (cible de la rapamytine chez les mammifères), qui régulent ensuite les voies de signalisation en aval, qui à leur tour favorisent la mort des neurones dopaminergiques à travers des récepteurs à domaine de mort. Les neurones dopaminergiques sont vulnérables au stress oxydatif et à l'attaque inflammatoire. Une augmentation des taux de l'oxyde nitrique synthase inductible observée dans la substance grise et le striatum des patients MP suggère que l'inflammation et la toxicité induites par les chémokines et les cytokines conduisent à un stress oxydatif qui contribue à la dégénérescence des neurones dopaminergiques et à la progression de la maladie. L'activation des lipopolysaccharides de la microglie proche des neurones dopaminergiques dans le locus niger provoque leur dégénérescence, ce qui semble être dû à une vulnérabilité sélective des neurones dopaminergiques à l'inflammation. Dans cet article, nous analysons le rôle de divers facteurs de transcription et voies de signalisation dans l'apparition de la MP.

Role of neuroinflammation and latent transcription factors in pathogenesis of Parkinson's disease.

Parkinson's disease (PD) the second most common age-associated progressive neurodegenerative disorder is characterized by loss of dopaminergic neurons, cytoplasmic inclusions of aggregated proteins (Lewy bodies), and neuroinflammation. The inflammation of neurons causes release of various inflammatory mediators (IFNs, EGF, IL5, IL6, HGF, LIF and BMP2). The hallmarks of neuroinflammation are the presence of activated microglia and reactive astrocytes in the parenchyma of the CNS and increased production of cytokines, chemokines, prostaglandins, complement cascade proteins, and reactive oxygen and nitrogen species (ROS/RNS) which in some cases can result in disruption of the blood brain barrier and direct participation of the adaptive immune system. Latent transcription factors such as NF-κB, STAT 3, AP1, and SMAD 7, Toll like receptors and FAF 1 are constitutively upregulated in activated microglia. Toll-like receptors when activated promote NF-κB signaling thus promoting a vicious cycle of neuroinflammation. These transcription factors take dopaminergic neurons to apoptotic pathway via p53 and other death domain receptors. Neuroprotective signaling pathways such as mTOR, SOCS, and TGF-ß down regulated during development of PD. YY1 signaling, which has protective effect against α-Synuclein toxicity, is significantly decreased in PD patients. In summary we can say that transcription factors promoting inflammation such as NF-κB, STAT 3, AP 1, and Toll-like receptors are constitutively upregulated in PD, while neuroprotective pathways such as mTOR, TGF-ß, and YY1 are substantially downregulated in microglia of PD patients.

Pharmacological studies on the anti-inflammatory and immunomodulatory role of pentoxifylline and its interaction with nitric oxide (NO) in experimental arthritis in rats.

AIM: Present study was designed to evaluate protective effects of pentoxifylline and its potentiation with low dose of nitric oxide (NO) modulators in adjuvant-induced experimental arthritis in rats. METHOD: Wistar rats (200-300 g, n = 8 per group) of both sexes were used in the study. On day "0" experimental arthritis was induced by injecting 0.2 ml of Complete Freund's adjuvant (CFA) in sub-planter region of right hind paw of animals. Pentoxifylline treatment alone and in combination with NO modulators was given (i.p.) from day 14 to 28. Various arthritic parameters were recorded and blood and joint synovial fluid was collected for biochemical analysis. RESULTS: CFA inoculation significantly increases (1) arthritic index (2) ankle diameter (3) paw volume (4) histopathology score (5) serum TNF-α, IL-6, IL-1ß and synovial TNF-α levels (p < 0.001) (6) serum Th1 and Th2 cytokine levels g) MDA levels in rat paw tissue homogenates (7) serum NF-κB levels. Significant decrease in serum IL-10 levels and SOD activity was observed in rats after CFA inoculation. Decrease in body weight and suppressed general quality of life of CFA inoculated rats was also observed. These CFA-induced arthritic changes were significantly reversed by pentoxifylline alone and in combination with low dose of NO modulators (p < 0.05). CONCLUSION: These results are suggestive of protective effects of pentoxifylline and its potentiation in combination with low dose of NO modulators. These results may provide new pharmacological therapy for management of rheumatoid arthritis (RA).