The effects of Phycocyanobilin on experimental arthritis involve the reduction in nociception and synovial neutrophil infiltration, inhibition of cytokine production, and modulation of the neuronal proteome.

Introduction: The antinociceptive and pharmacological activities of C-Phycocyanin (C-PC) and Phycocyanobilin (PCB) in the context of inflammatory arthritis remain unexplored so far. In the present study, we aimed to assess the protective actions of these compounds in an experimental mice model that replicates key aspects of human rheumatoid arthritis. Methods: Antigen-induced arthritis (AIA) was established by intradermal injection of methylated bovine serum albumin in C57BL/6 mice, and one hour before the antigen challenge, either C-PC (2, 4, or 8 mg/kg) or PCB (0.1 or 1 mg/kg) were administered intraperitoneally. Proteome profiling was also conducted on glutamate-exposed SH-SY5Y neuronal cells to evaluate the PCB impact on this key signaling pathway associated with nociceptive neuronal sensitization. Results and discussion: C-PC and PCB notably ameliorated hypernociception, synovial neutrophil infiltration, myeloperoxidase activity, and the periarticular cytokine concentration of IFN-γ, TNF-α, IL-17A, and IL-4 dose-dependently in AIA mice. In addition, 1 mg/kg PCB downregulated the gene expression for T-bet, RORγ, and IFN-γ in the popliteal lymph nodes, accompanied by a significant reduction in the pathological arthritic index of AIA mice. Noteworthy, neuronal proteome analysis revealed that PCB modulated biological processes such as pain, inflammation, and glutamatergic transmission, all of which are involved in arthritic pathology. Conclusions: These findings demonstrate the remarkable efficacy of PCB in alleviating the nociception and inflammation in the AIA mice model and shed new light on mechanisms underlying the PCB modulation of the neuronal proteome. This research work opens a new avenue to explore the translational potential of PCB in developing a therapeutic strategy for inflammation and pain in rheumatoid arthritis.

Evidence of SARS-CoV-2 infection in postmortem lung, kidney, and liver samples, revealing cellular targets involved in COVID-19 pathogenesis.

There is an urgent need to understand severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-host interactions involved in virus spread and pathogenesis, which might contribute to the identification of new therapeutic targets. In this study, we investigated the presence of SARS-CoV-2 in postmortem lung, kidney, and liver samples of patients who died with coronavirus disease (COVID-19) and its relationship with host factors involved in virus spread and pathogenesis, using microscopy-based methods. The cases analyzed showed advanced stages of diffuse acute alveolar damage and fibrosis. We identified the SARS-CoV-2 nucleocapsid (NC) in a variety of cells, colocalizing with mitochondrial proteins, lipid droplets (LDs), and key host proteins that have been implicated in inflammation, tissue repair, and the SARS-CoV-2 life cycle (vimentin, NLRP3, fibronectin, LC3B, DDX3X, and PPARγ), pointing to vimentin and LDs as platforms involved not only in the viral life cycle but also in inflammation and pathogenesis. SARS-CoV-2 isolated from a patient´s nasal swab was grown in cell culture and used to infect hamsters. Target cells identified in human tissue samples included lung epithelial and endothelial cells; lipogenic fibroblast-like cells (FLCs) showing features of lipofibroblasts such as activated PPARγ signaling and LDs; lung FLCs expressing fibronectin and vimentin and macrophages, both with evidence of NLRP3- and IL1ß-induced responses; regulatory cells expressing immune-checkpoint proteins involved in lung repair responses and contributing to inflammatory responses in the lung; CD34+ liver endothelial cells and hepatocytes expressing vimentin; renal interstitial cells; and the juxtaglomerular apparatus. This suggests that SARS-CoV-2 may directly interfere with critical lung, renal, and liver functions involved in COVID-19-pathogenesis.

Anti-inflammatory mechanisms and pharmacological actions of phycocyanobilin in a mouse model of experimental autoimmune encephalomyelitis: A therapeutic promise for multiple sclerosis.

Cytokines, demyelination and neuroaxonal degeneration in the central nervous system are pivotal elements implicated in the pathogenesis of multiple sclerosis (MS) and its nonclinical model of experimental autoimmune encephalomyelitis (EAE). Phycocyanobilin (PCB), a chromophore of the biliprotein C-Phycocyanin (C-PC) from Spirulina platensis, has antioxidant, immunoregulatory and anti-inflammatory effects in this disease, and it could complement the effect of other Disease Modifying Treatments (DMT), such as Interferon-ß (IFN-ß). Here, our main goal was to evaluate the potential PCB benefits and its mechanisms of action to counteract the chronic EAE in mice. MOG35-55-induced EAE was implemented in C57BL/6 female mice. Clinical signs, pro-inflammatory cytokines levels by ELISA, qPCR in the brain and immunohistochemistry using precursor/mature oligodendrocytes cells antibodies in the spinal cord, were assessed. PCB enhanced the neurological condition, and waned the brain concentrations of IL-17A and IL-6, pro-inflammatory cytokines, in a dose-dependent manner. A down- or up-regulating activity of PCB at 1 mg/kg was identified in the brain on three (LINGO1, NOTCH1, and TNF-α), and five genes (MAL, CXCL12, MOG, OLIG1, and NKX2-2), respectively. Interestingly, a reduction of demyelination, active microglia/macrophages density, and axonal damage was detected along with an increase in oligodendrocyte precursor cells and mature oligodendrocytes, when assessed the spinal cords of EAE mice that took up PCB. The studies in vitro in rodent encephalitogenic T cells and in vivo in the EAE mouse model with the PCB/IFN-ß combination, showed an enhanced positive effect of this combined therapy. Overall, these results demonstrate the anti-inflammatory activity and the protective properties of PCB on the myelin and support its use with IFN-ß as an improved DMT combination for MS.

Positive effects of Phycocyanobilin on gene expression in glutamate-induced excitotoxicity in SH-SY5Y cells and animal models of multiple sclerosis and cerebral ischemia.

Background: Oxidative stress has a predominant role in the pathogenesis of neurodegenerative diseases and therefore the modulation of genes and the identification of biological pathways associated with antioxidant therapies, have an impact on its treatment. Objective: The objective of this study was the comparison of 2 methods for the analysis of real-time PCR (qPCR) data, through the use of the evaluation of genes that mediate the effect of Phycocyanobilin (PCB) and its validation in animal models. Methods: We evaluated the effect of PCB:" in vitro" on gene modulation through qPCR analyzed by parametric ANOVA and multivariate principal component analysis (PCA) in a model of glutamate-induced excitotoxicity in the SH-SY5Y cell line and" in vivo"; in animal models of multiple sclerosis (MS) and cerebral ischemia (CI). Results: The results showed that PCA is a robust and powerful method that allows the assessment of gene expression profiles. We detected the significant down-regulation of the CYBB (NOX2), and HMOX1 by the action of PCB in SH-5YSH cell line insulted with Glutamate. The decrease in pro-inflammatory cytokines and markers related to apoptosis and innate immune response, mediated the effect of PCB in the animal models of MS and CI, respectively. Conclusion: We concluded that the mechanisms by which PCB protected cells included the reduction of oxidative stress damage, which could contribute to its clinical efficacy for the treatment of neurodegenerative diseases.

Novel Insights into the Molecular Mechanisms Involved in the Neuroprotective Effects of C-Phycocyanin against Brain Ischemia in Rats.

BACKGROUND: Ischemic stroke produces a large health impact worldwide, with scarce therapeutic options. OBJECTIVE: This study aimed to reveal the role of NADPH oxidase and neuroinflammatory genes in the cerebral anti-ischemic effects of C-Phycocyanin (C-PC), the chief biliprotein of Spirulina platensis. METHODS: Rats with either focal cerebral ischemia/reperfusion (I/R) or acute brain hypoperfusion, received C-PC at different doses, or a vehicle, for up to 6 h post-stroke. Neurological, behavioral and histochemical parameters were assessed in I/R rats at 24 h. Cerebral gene expression and hippocampal neuron viability were evaluated in hypoperfused rats at acute (24 h) or chronic phases (30 days), respectively. A molecular docking analysis of NOX2 and C-PC-derived Phycocyanobilin (PCB) was also performed. RESULTS: C-PC, obtained with a purity of 4.342, significantly reduced the infarct volume and neurological deficit in a dose-dependent manner, and improved the exploratory activity of I/R rats. This biliprotein inhibited NOX2 expression, a crucial NADPH oxidase isoform in the brain, and the superoxide increase produced by the ischemic event. Moreover, C-PC-derived PCB showed a high binding affinity in silico with NOX2. C-PC downregulated the expression of pro-inflammatory genes (IFN-γ, IL-6, IL-17A, CD74, CCL12) and upregulated immune suppressive genes (Foxp3, IL-4, TGF-ß) in hypoperfused brain areas. This compound also decreased chronic neuronal death in the hippocampus of hypoperfused rats. CONCLUSION: These results suggest that the inhibition of cerebral NADPH oxidase and the improvement of neuroinflammation are key mechanisms mediating the neuroprotective actions of C-PC against brain ischemia.

The microglial NLRP3 inflammasome is involved in human SARS-CoV-2 cerebral pathogenicity: A report of three post-mortem cases.

We herein report, by using confocal immunofluorescence, the colocalization of the SARS-CoV-2 nucleocapsid within neurons, astrocytes, oligodendrocytes and microglia in three deceased COVID-19 cases, of between 78 and 85 years of age at death. The viral nucleocapsid was detected together with its ACE2 cell entry receptor, as well as the NLRP3 inflammasome in cerebral cortical tissues. It is noteworthy that NLRP3 was colocalized with CD68 + macrophages in the brain and lung of the deceased, suggesting the critical role of this type of inflammasome in SARS-CoV-2 lesions of the nervous system/lungs and supporting its potential role as a therapeutic target.

Gossypitrin, A Naturally Occurring Flavonoid, Attenuates Iron-Induced Neuronal and Mitochondrial Damage.

The disruption of iron homeostasis is an important factor in the loss of mitochondrial function in neural cells, leading to neurodegeneration. Here, we assessed the protective action of gossypitrin (Gos), a naturally occurring flavonoid, on iron-induced neuronal cell damage using mouse hippocampal HT-22 cells and mitochondria isolated from rat brains. Gos was able to rescue HT22 cells from the damage induced by 100 µM Fe(II)-citrate (EC50 8.6 µM). This protection was linked to the prevention of both iron-induced mitochondrial membrane potential dissipation and ATP depletion. In isolated mitochondria, Gos (50 µM) elicited an almost complete protection against iron-induced mitochondrial swelling, the loss of mitochondrial transmembrane potential and ATP depletion. Gos also prevented Fe(II)-citrate-induced mitochondrial lipid peroxidation with an IC50 value (12.45 µM) that was about nine time lower than that for the tert-butylhydroperoxide-induced oxidation. Furthermore, the flavonoid was effective in inhibiting the degradation of both 15 and 1.5 mM 2-deoxyribose. It also decreased Fe(II) concentration with time, while increasing O2 consumption rate, and impairing the reduction of Fe(III) by ascorbate. Gos-Fe(II) complexes were detected by UV-VIS and IR spectroscopies, with an apparent Gos-iron stoichiometry of 2:1. Results suggest that Gos does not generally act as a classical antioxidant, but it directly affects iron, by maintaining it in its ferric form after stimulating Fe(II) oxidation. Metal ions would therefore be unable to participate in a Fenton-type reaction and the lipid peroxidation propagation phase. Hence, Gos could be used to treat neuronal diseases associated with iron-induced oxidative stress and mitochondrial damage.

C-Phycocyanin-derived Phycocyanobilin as a Potential Nutraceutical Approach for Major Neurodegenerative Disorders and COVID-19- induced Damage to the Nervous System.

The edible cyanobacterium Spirulina platensis and its chief biliprotein C-Phycocyanin have shown protective activity in animal models of diverse human health diseases, often reflecting antioxidant and anti-inflammatory effects. The beneficial effects of C-Phycocyanin seem likely to be primarily attributable to its covalently attached chromophore Phycocyanobilin (PCB). Within cells, biliverdin is generated from free heme and it is subsequently reduced to bilirubin. Although bilirubin can function as an oxidant scavenger, its potent antioxidant activity reflects its ability to inactivate some isoforms of NADPH oxidase. Free bilirubin can also function as an agonist for the aryl hydrocarbon receptor (AhR); this may explain its ability to promote protective Treg activity in cellular and rodent models of inflammatory disease. AhR agonists also promote transcription of the gene coding for Nrf-2, and hence can up-regulate phase 2 induction of antioxidant enzymes, such as HO-1. Hence, it is proposed that C-Phycocyanin/PCB chiefly exert their protective effects via inhibition of NADPH oxidase activity, as well as by AhR agonism that both induces Treg activity and up-regulates phase 2 induction. This simple model may explain their potent antioxidant/antiinflammatory effects. Additionally, PCB might mimic biliverdin in activating anti-inflammatory signaling mediated by biliverdin reductase. This essay reviews recent research in which CPhycocyanin and/or PCB, administered orally, parenterally, or intranasally, have achieved marked protective effects in rodent and cell culture models of Ischemic Stroke and Multiple Sclerosis, and suggests that these agents may likewise be protective for Alzheimer's disease, Parkinson's disease, and in COVID-19 and its neurological complications.

Phycocyanobilin reduces brain injury after endothelin-1- induced focal cerebral ischaemia.

Pharmacological therapies for interrupting biochemical events of the ischaemic cascade and protecting against stroke in humans are as yet unavailable. Up to now, the neuroprotective activity in cerebral ischaemia of phycocyanobilin (PCB), a tetrapyrrolic natural antioxidant, has not been fully examined. Here, we evaluated if PCB protects PC12 neuronal cells against oxygen and glucose deprivation plus reperfusion, and its protective effects in a rat model of endothelin-1-induced focal brain ischaemia. PCB was purified from the cyanobacteria Spirulina platensis and characterized by spectrophotometric, liquid and gas chromatography and mass spectrometry techniques. In Wistar rats, PCB at 50, 100 and 200 µg/kg or phosphate-buffered saline (vehicle) was administered intraperitoneally at equal subdoses in a therapeutic schedule (30 minutes, 1, 3 and 6 hours after the surgery). Brain expression of myelin basic protein (MBP) and the enzyme CNPase was determined by immunoelectron microscopy. PCB was obtained with high purity (>95%) and the absence of solvent contaminants and was able to ameliorate PC12 cell ischaemic injury. PCB treatment significantly decreased brain infarct volume, limited the exploratory behaviour impairment and preserved viable cortical neurons in ischaemic rats in a dose-dependent manner, compared to the vehicle group. Furthermore, PCB at high doses restored the MBP and CNPase expression levels in ischaemic rats. An improved PCB purification method from its natural source is reported, obtaining PCB that is suitable for pharmacological trials showing neuroprotective effects against experimental ischaemic stroke. Therefore, PCB could be a therapeutic pharmacological alternative for ischaemic stroke patients.

C-Phycocyanin and Phycocyanobilin as Remyelination Therapies for Enhancing Recovery in Multiple Sclerosis and Ischemic Stroke: A Preclinical Perspective.

Myelin loss has a crucial impact on behavior disabilities associated to Multiple Sclerosis (MS) and Ischemic Stroke (IS). Although several MS therapies are approved, none of them promote remyelination in patients, limiting their ability for chronic recovery. With no available therapeutic options, enhanced demyelination in stroke survivors is correlated with a poorer behavioral recovery. Here, we show the experimental findings of our group and others supporting the remyelinating effects of C-Phycocyanin (C-PC), the main biliprotein of Spirulina platensis and its linked tetrapyrrole Phycocyanobilin (PCB), in models of these illnesses. C-PC promoted white matter regeneration in rats and mice affected by experimental autoimmune encephalomyelitis. Electron microscopy analysis in cerebral cortex from ischemic rats revealed a potent remyelinating action of PCB treatment after stroke. Among others biological processes, we discussed the role of regulatory T cell induction, the control of oxidative stress and pro-inflammatory mediators, gene expression modulation and COX-2 inhibition as potential mechanisms involved in the C-PC and PCB effects on the recruitment, differentiation and maturation of oligodendrocyte precursor cells in demyelinated lesions. The assembled evidence supports the implementation of clinical trials to demonstrate the recovery effects of C-PC and PCB in these diseases.

Anti-cancer activity of a new dihydropyridine derivative, VdiE-2N, in head and neck squamous cell carcinoma.

This study aims to examine the effects of a new 1,4-dihydropyridine derivative, VdiE-2N, on cell signaling pathways and mitochondrial events in head and neck squamous cell carcinoma (HNSCC) cells, and on a mice model of xenograft tumor growth/cell proliferation. Four HNSCC cell lines (HN13, HN12, HN6, and CAL27), HEK293 cells (human embryonic kidney 293 cells), and human oral healthy mucosa fibroblasts (OHMF) were used for in vitro assessment of cell viability (resazurin assay) and invasion capacity (modified Boyden chamber assay), and mitochondrial membrane potential (JC-1 fluorescence assay), morphology (transmission electron microscopy), and number of mitochondria (MitoTracker® imaging). SET and pDRP1 proteins were analyzed by immunofluorescence, and proteins involved in cell death/survival pathways were analyzed by Western blotting. HN12 xenograft tumors were established in the flank of Balb/c nude mice, and their characteristics and sensitivity to VdiE-2N were determined by immunohistochemistry and histology. VdiE-2N decreased cell viability in HNSCC cells (IC50 = 9.56 and 22.45µM for HN13 and HN12 cells, respectively) more strongly than it decreased cell viability in OHMF and HEK293 cells (IC50 = 32.90 and > 50µM, respectively). In HN13 cells, VdiE-2N dissipated mitochondrial membrane potential and altered the mitochondria size, shape, and number in a concentration-dependent manner, as well as it induced apoptosis and reduced their invasion capacity. Treatment of mice bearing xenograft tumors with VdiE-2N significantly diminished proliferation of cancer cells. Therefore, VdiE-2N induces HNSCC cell death in vitro through mitochondria-mediated apoptotic pathways and dampens tumor growth in vivo, thus supporting a potential anti-cancer effect.

Beneficial effects of oral administration of C-Phycocyanin and Phycocyanobilin in rodent models of experimental autoimmune encephalomyelitis.

The only three oral treatments currently available for multiple sclerosis (MS) target the relapsing forms of the disease and concerns regarding efficacy, safety and tolerability limit their use. Identifying novel oral disease-modifying therapies for MS, targeting both its inflammatory and neurodegenerative components is still a major goal. AIM: The scope of this study was to provide evidence that the oral administration of C-Phycocyanin (C-PC), the main biliprotein of the Spirulina platensis cyanobacteria and its tetrapyrrolic prosthetic group, Phycocyanobilin (PCB), exert ameliorating actions on rodent models of experimental autoimmune encephalomyelitis (EAE). MAIN METHODS: EAE was induced in Lewis rats using the spinal cord encephalitogen from Sprague Dawley rats and in C57BL6 mice with MOG35-55 peptide. Clinical signs, motor function, oxidative stress markers, cytokine levels by ELISA and transmission electron microscopy analysis were assessed. KEY FINDINGS: Either prophylactic or early therapeutic administration of C-PC to Lewis rats with EAE, significantly improved clinical signs and restored the motor function of the animals. Furthermore, C-PC positively modulated oxidative stress markers measured in brain homogenate and serum and protected the integrity of cerebral myelin sheaths as shown by transmission electron microscopy analysis. In C57BL/6 mice with EAE, PCB orally improved clinical status of the animals and reduced the expression levels of brain IL-6 and IFN-γ proinflammatory cytokines. SIGNIFICANCE: These results, for the first time, support the fact that both C-PC and PCB administered orally could potentially improve neuroinflammation, protect from demyelination and axonal loss, which may be translated into an improved quality of life for MS patients.

The cytotoxic effects of VE-3N, a novel 1,4-dihydropyridine derivative, involve the mitochondrial bioenergetic disruption via uncoupling mechanisms.

Several 1,4-dihydropyridine derivatives overcome the multidrug resistance in tumors, but their intrinsic cytotoxic mechanisms remain unclear. Here we addressed if mitochondria are involved in the cytotoxicity of the novel 1,4-dihydropyridine derivative VE-3N [ethyl 6-chloro-5-formyl-2-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylate] towards cancer cells by employing hepatic carcinoma (HepG2) cells and isolated rat liver mitochondria. In HepG2 cells, VE-3N induced mitochondrial membrane potential dissipation, ATP depletion, annexin V/propidium iodide double labeling, and Hoechst staining; events indicating apoptosis induction. In isolated rat liver mitochondria, VE-3N promoted mitochondrial uncoupling by exerting protonophoric actions and by increasing membrane fluidity. Mitochondrial uncoupling was evidenced by an increase in resting respiration, dissipation of mitochondrial membrane potential, inhibition of Ca2+ uptake, stimulation of Ca2+ release, decrease in ATP synthesis, and swelling of valinomycin-treated organelles in hyposmotic potassium acetate media. Furthermore, uncoupling concentrations of VE-3N in the presence of Ca2+ plus ruthenium red induced the mitochondrial permeability transition process. These results indicate that mitochondrial uncoupling is potentially involved in the VE-3N cytotoxic actions towards HepG2 cells. Considering that hepatocellular carcinoma is the most common form of liver cancer, our findings may open a new avenue for the development of VE-3N-based cancer therapies, and help to unravel the cytotoxic mechanisms of 1,4-dihydropyridines towards cancer cells.

Comparative Neuroregenerative Effects of C-Phycocyanin and IFN-Beta in a Model of Multiple Sclerosis in Mice.

Multiple Sclerosis (MS) therapies approved so far are unable to effectively reverse the chronic phase of the disease or improve the remyelination process. Here our aim is to evaluate the effects of C-Phycocyanin (C-Pc), a biliprotein from Spirulina platensis with anti-oxidant, anti-inflammatory and cytoprotective properties, in a chronic model of experimental autoimmune encephalomyelitis (EAE) in mice. C-Pc (2, 4 or 8 mg/kg i.p.) or IFN-beta (2000 IU, s.c.) was administered daily once a day or every other day, respectively, starting at disease onset, which differ among EAE mice between 11 and 15 days postinduction. Histological and immunohistochemistry (anti-Mac-3, anti-CD3 and anti-APP) assessments were performed in spinal cord in the postinduction time. Global gene expression in the brain was analyzed with the Illumina Mouse WG-6_V2 BeadChip microarray and the expression of particular genes, assessed by qPCR using the Fast SYBR Green RT-PCR Master Mix. Oxidative stress parameters (malondialdehyde, peroxidation potential, CAT/SOD ratio and GSH) were determined spectrophoto-metrically. Results showed that C-Pc ameliorates the clinical deterioration of animals, an effect that expresses the reduction of the inflammatory infiltrates invading the spinal cord tissue, the axonal preservation and the down-regulation of IL-17 expression in brain tissue and serum. C-Pc and IFN-beta improved the redox status in mice subjected to EAE, while microarray analysis showed that both treatments shared a common subset of differentially expressed genes, although they also differentially modulated another subset of genes. Specifically, C-Pc mainly modulated the expression of genes related to remyelination, gliogenesis and axon-glia processes. Taken together, our results indicate that C-Pc has significant therapeutic effects against EAE, mediated by the dynamic regulation of multiple biological processes.

Clusianone, a naturally occurring nemorosone regioisomer, uncouples rat liver mitochondria and induces HepG2 cell death.

Clusianone is a member of the polycyclic polyprenylated acylphloroglucinol family of natural products; its cytotoxic mechanism is unknown. Clusianone is a structural isomer of nemorosone, which is a mitochondrial uncoupler and a well-known cytotoxic anti-cancer agent; thus, we addressed clusianone action at the mitochondria and its potential cytotoxic effects on cancer cells. In the HepG2 hepatocarcinoma cell line, clusianone induced mitochondrial membrane potential dissipation, ATP depletion and phosphatidyl serine externalization; this later event is indicative of apoptosis induction. In isolated mitochondria from rat liver, clusianone promoted protonophoric mitochondrial uncoupling. This was evidenced by the dissipation of mitochondrial membrane potential, an increase in resting respiration, an inhibition of Ca(2+) influx, stimulation of Ca(2+) efflux in Ca(2+)-loaded mitochondria, a decrease in ATP and NAD(P)H levels, generation of ROS, and swelling of valinomycin-treated organelles in hyposmotic potassium acetate media. The cytotoxic and uncoupling actions of clusianone were appreciably less than those of nemorosone, likely due to the presence of an intra-molecular hydrogen bond with the juxtaposed carbonyl group at the C15 position. Therefore, clusianone is capable of pharmacologically increasing the leakage of protons from the mitochondria and with favorable cytotoxicity in relation to nemorosone.

JM-20, a novel benzodiazepine­dihydropyridine hybrid molecule, protects mitochondria and prevents ischemic insult-mediated neural cell death in vitro.

The ischemic stroke cascade is composed of several pathophysiological events, providing multiple targets for pharmacological intervention. JM-20 (3-ethoxycarbonyl-2-methyl-4-(2-nitrophenyl)-4,11-dihydro-1H-pyrido[2,3-b][1,5]benzodiazepine) is a novel hybrid molecule, in which a benzodiazepine portion is covalently linked to a dihydropyridine ring, forming a new chemical entity with potential multisite neuroprotective activity. In the present study, JM-20 prevented PC-12 cell death induced either by glutamate, hydrogen peroxide or KCN-mediated chemical hypoxia. This molecule also protected cerebellar granule neurons from glutamate or glutamate plus pentylenetetrazole-induced damage at very low micromolar concentrations. In rat liver mitochondria, JM-20, at low micromolar concentrations, prevented the Ca2+-induced mitochondrial permeability transition, as assessed by mitochondrial swelling, membrane potential dissipation and organelle release of the pro-apoptotic protein cytochrome c. JM-20 also inhibited the mitochondrial hydrolytic activity of F1F0-ATP synthase and Ca2+ influx. Therefore, JM-20 may be a multi-target neuroprotective agent, promoting reductions in neuronal excitotoxic injury and the protection of the mitochondria from Ca2+-induced impairment as well as the preservation of cellular energy balance.

Phycocyanobilin promotes PC12 cell survival and modulates immune and inflammatory genes and oxidative stress markers in acute cerebral hypoperfusion in rats.

Since the inflammatory response and oxidative stress are involved in the stroke cascade, we evaluated here the effects of Phycocyanobilin (PCB, the C-Phycocyanin linked tetrapyrrole) on PC12 cell survival, the gene expression and the oxidative status of hypoperfused rat brain. After the permanent bilateral common carotid arteries occlusion (BCCAo), the animals were treated with saline or PCB, taking samples 24h post-surgery. Global gene expression was analyzed with GeneChip Rat Gene ST 1.1 from Affymetrix; the expression of particular genes was assessed by the Fast SYBR Green RT-PCR Master Mix and Bioplex methods; and redox markers (MDA, PP, CAT, SOD) were evaluated spectrophotometrically. The PCB treatment prevented the H2O2 and glutamate induced PC12 cell injury assessed by the MTT assay, and modulated 190 genes (93 up- and 97 down-regulated) associated to several immunological and inflammatory processes in BCCAo rats. Furthermore, PCB positively modulated 19 genes mostly related to a detrimental pro-inflammatory environment and counteracted the oxidative imbalance in the treated BCCAo animals. Our results support the view of an effective influence of PCB on major inflammatory mediators in acute cerebral hypoperfusion. These results suggest that PCB has a potential to be a treatment for ischemic stroke for which further studies are needed.

C-Phycocyanin protects SH-SY5Y cells from oxidative injury, rat retina from transient ischemia and rat brain mitochondria from Ca2+/phosphate-induced impairment.

Oxidative stress and mitochondrial impairment are essential in the ischemic stroke cascade and eventually lead to tissue injury. C-Phycocyanin (C-PC) has previously been shown to have strong antioxidant and neuroprotective actions. In the present study, we assessed the effects of C-PC on oxidative injury induced by tert-butylhydroperoxide (t-BOOH) in SH-SY5Y neuronal cells, on transient ischemia in rat retinas, and in the calcium/phosphate-induced impairment of isolated rat brain mitochondria (RBM). In SH-SY5Y cells, t-BOOH induced a significant reduction of cell viability as assessed by an MTT assay, and the reduction was effectively prevented by treatment with C-PC in the low micromolar concentration range. Transient ischemia in rat retinas was induced by increasing the intraocular pressure to 120mmHg for 45min, which was followed by 15min of reperfusion. This event resulted in a cell density reduction to lower than 50% in the inner nuclear layer (INL), which was significantly prevented by the intraocular pre-treatment with C-PC for 15min. In the RBM exposed to 3mM phosphate and/or 100µM Ca(2+), C-PC prevented in the low micromolar concentration range, the mitochondrial permeability transition as assessed by mitochondrial swelling, the membrane potential dissipation, the increase of reactive oxygen species levels and the release of the pro-apoptotic cytochrome c. In addition, C-PC displayed a strong inhibitory effect against an electrochemically-generated Fenton reaction. Therefore, C-PC is a potential neuroprotective agent against ischemic stroke, resulting in reduced neuronal oxidative injury and the protection of mitochondria from impairment.

C-Phycocyanin is neuroprotective against global cerebral ischemia/reperfusion injury in gerbils.

Although the huge economic and social impact and the predicted incidence increase, neuroprotection for ischemic stroke remains as a therapeutically empty niche. In the present study, we investigated the rationale of the C-Phycocyanin (C-PC) treatment on global cerebral ischemia/reperfusion (I/R) injury in gerbils. We demonstrated that C-PC given either prophylactically or therapeutically was able to significantly reduce the infarct volume as assessed by triphenyltetrazolium chloride (TTC) staining and the neurological deficit score 24h post-stroke. In addition, C-PC exhibited a protective effect against hippocampus neuronal cell death, and significantly improved the functional outcome (locomotor behavior) and gerbil survival after 7 days of reperfusion. Malondialdehyde (MDA), peroxidation potential (PP) and ferric reducing ability of plasma (FRAP) were assayed in serum and brain homogenates to evaluate the redox status 24h post-stroke. The treatment with C-PC prevented the lipid peroxidation and the increase of FRAP in both tissue compartments. These results suggest that the protective effects of C-PC are most likely due to its antioxidant activity, although its anti-inflammatory and immuno-modulatory properties reported elsewhere could also contribute to neuroprotection. To our knowledge, this is the first report of the neuroprotective effect of C-PC in an experimental model of global cerebral I/R damage, and strongly indicates that C-PC may represent a potential preventive and acute disease modifying pharmacological agent for stroke therapy.

C-Phycocyanin ameliorates experimental autoimmune encephalomyelitis and induces regulatory T cells.

For decades Experimental Autoimmune Encephalitis (EAE) has remained as an unsurpassed multiple sclerosis (MS) animal model. C-Phycocyanin (C-Pc) has been reported to exhibit pharmacological properties that may be expected to symptomatically improve EAE and MS. However, in this paper we reveal a basic underlying mechanism that may provide a new approach to the rationale of the overall beneficial effect of this natural antioxidant. We demonstrate that C-Pc is able to trigger mechanisms preventing or downgrading EAE expression and induces a regulatory T cell (Treg) response, in peripheral blood mononuclear cells (PBMC) from MS patients. These results agree with reports suggesting that Treg limit acute MS attacks and that C-Pc may act as a neuroprotector and thereby reverts the organic and functional damage in neurodegenerative disorders of the central nervous system (CNS). Moreover, evidence is provided on the antioxidant activity of C-Pc within the CNS, intended to improve the myelin and axonal damage of EAE induced Lewis rats. Our results indicate that specific Treg activation may represent a central and essential mechanism in supporting the therapeutic potential of C-Pc for MS and may lead to new and more effective therapies; this property would then complement and enhance other proven active principles such as interferons (IFN), giving rise to combined therapies.