Carnosine suppresses oxygen-glucose deprivation/recovery-induced proliferation and migration of reactive astrocytes of rats in vitro

Reactive astrogliosis induced by TNF-α is associated with upregulated AEG-1 together with activated NF-κB pathway in vitro

Astrocyte-elevated gene-1 (AEG-1/MTDH/LYRIC) has garnered signficant attention in cancer research, yet, its role in inflammation-associated astrogliosis remains underexplored. This study aims to elucidate the effects of AEG-1 on reactive astrogliosis, including proliferation, migration, and glutamate uptake in primary astrocytes derived from rats. We first confirmed the effect of AEG-1 on these parameters. Subsequently, we investigated whether AEG-1 plays a role in the process of pro-inflammation factors such as tumor necrosis factor-alpha (TNF-α) induced astrogliosis. Our findings revealed that AEG-1-lentivirus infection led to hypertrophic cell bodies and enhanced expression of astrogliosis markers, including glial fibrillary acidic protein (GFAP) and vimentin. Additionally, AEG-1 was found to upregulate the mRNA and protein expression levels of EAAT2, a major glutamate transporter in the brain predominantly expressed by astrocytes and responsible for 90% of glutamate clearance. Furthermore, TNF-α was shown to promote astrogliosis, as well as astrocyte proliferation and migration, by upregulating AEG-1 expression through the NF-κB pathway. Collectively, these results suggest a potential role for AEG-1 in inflammation-related astrogliosis.

P-hydroxy benzaldehyde facilitates reprogramming of reactive astrocytes into neurons via endogenous transcriptional regulation

BACKGROUND

Cerebral ischemia leads to linguistic and motor dysfunction, as the death of neurons in ischemic core is permanent and non-renewable. An innovative avenue is to induce and/or facilitate reprogramming of adjacent astrocytes into neurons to replace the lost neurons and re-establish brain homeostasis.

PURPOSE

This study aimed to investigate whether the p-hydroxy benzaldehyde (p-HBA), a phenolic compound isolated from Gastrodia elata Blume, could facilitate the reprogramming of oxygen-glucose deprivation/reperfusion (OGD/R)-damaged astrocytes into neurons.

STUDY DESIGN/METHODS

The primary parenchymal astrocytes of rat were exposure to OGD and reperfusion with define culture medium. Cells were then incubated with different concentration of p-HBA (1, 10, 100, 400 μM) and collected at desired time point for reprogramming process analysis.

RESULTS

OGD/R could elicit endogenous neurogenic program in primary parenchymal astrocytes of rat under define culture condition, and these so-called reactive astrocytes could be reprogrammed into neurons. However, the neonatal neurons produced by this endogenous procedure could not develop into mature neurons, and the conversion rate was only 1.9%. Treatment of these reactive astrocytes with p-HBA could successfully promote the conversion rate to 6.1%, and the neonatal neurons could develop into mature neurons within 14 days. Further analysis showed that p-HBA down-regulated the Notch signal component genes Dll1, Hes1 and SOX2, while the transcription factor NeuroD1 was up-regulated.

CONCLUSION

The results of this study demonstrated that p-HBA facilitated the astrocyte-to-neuron conversion. This chemical reprogramming was mediated by inhibition of Notch1 signaling pathway and transcriptional activation of NeuroD1.

LOX-1 mediates inflammatory activation of microglial cells through the p38-MAPK/NF-κB pathways under hypoxic-ischemic conditions

BACKGROUND

Microglial cells play an important role in the immune system in the brain. Activated microglial cells are not only injurious but also neuroprotective. We confirmed marked lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) expression in microglial cells in pathological lesions in the neonatal hypoxic-ischemic encephalopathy (nHIE) model brain. LOX-1 is known to be an activator of cytokines and chemokines through intracellular pathways. Here, we investigated a novel role of LOX-1 and the molecular mechanism of LOX-1 gene transcription microglial cells under hypoxic and ischemic conditions.

METHODS

We isolated primary rat microglial cells from 3-day-old rat brains and confirmed that the isolated cells showed more than 98% Iba-1 positivity with immunocytochemistry. We treated primary rat microglial cells with oxygen glucose deprivation (OGD) as an in vitro model of nHIE. Then, we evaluated the expression levels of LOX-1, cytokines and chemokines in cells treated with or without siRNA and inhibitors compared with those of cells that did not receive OGD-treatment. To confirm transcription factor binding to the OLR-1 gene promoter under the OGD conditions, we performed a luciferase reporter assay and chromatin immunoprecipitation assay. In addition, we analyzed reactive oxygen species and cell viability.

RESULTS

We found that defects in oxygen and nutrition induced LOX-1 expression and led to the production of inflammatory mediators, such as the cytokines IL-1β, IL-6 and TNF-α; the chemokines CCL2, CCL5 and CCL3; and reactive oxygen/nitrogen species. Then, the LOX-1 signal transduction pathway was blocked by inhibitors, LOX-1 siRNA, the p38-MAPK inhibitor SB203580 and the NF-κB inhibitor BAY11-7082 suppressed the production of inflammatory mediators. We found that NF-κB and HIF-1α bind to the promoter region of the OLR-1 gene. Based on the results of the luciferase reporter assay, NF-κB has strong transcriptional activity. Moreover, we demonstrated that LOX-1 in microglial cells was autonomously overexpressed by positive feedback of the intracellular LOX-1 pathway.

CONCLUSION

The hypoxic/ischemic conditions of microglial cells induced LOX-1 expression and activated the immune system. LOX-1 and its related molecules or chemicals may be major therapeutic candidates. Video abstract.

The pleiotropic of GLP-1/GLP-1R axis in central nervous system diseases

Glucagon-like peptide-1(GLP-1) is a multifunctional polypeptide throughout the lifespan via activating Glucagon-like peptide-1 receptor (GLP-1R).GLP-1 can affect food ingestion, enhance the secretion of insulin from pancreatic islets induced by glucose and be utilized to treat type 2 diabetes mellitus(T2DM).But, accumulating evidences from the decades suggest that activation GLP-1R can not only regulate the blood glucose, but also sustain the homeostasis of intracellular environment and protect neuron from various damaged responses such as oxidative stress, inflammation, excitotoxicity, ischemia and so on. And more and more pre-clinical and clinical studies identified that GLP-1 and its analogues may play a significant role in improving multiple central nervous system (CNS) diseases including neurodegenerative diseases, epilepsy, mental disorders, ischemic stroke, hemorrhagic stroke, traumatic brain injury, spinal cord injury, chronic pain, addictive disorders, other diseases neurological complications and so on. In order to better reveal the relationship between GLP-1/GLP-1R axis and the growth, development and survival of neurons, herein, this review is aimed to summarize the multi-function of GLP-1/GLP-1R axis in CNS diseases.

Neutrophil β1 adrenoceptor blockade blunts stroke-associated neuroinflammation

BACKGROUND AND PURPOSE

Reperfusion therapy is the standard of care for ischaemic stroke; however, there is a need to identify new therapeutic targets able to ameliorate cerebral damage. Neutrophil β₁ adrenoceptors (β1AR) have been linked to neutrophil migration during exacerbated inflammation. Given the central role of neutrophils in cerebral damage during stroke, we hypothesize that β1AR blockade will improve stroke outcomes.

EXPERIMENTAL APPROACH

Rats were subjected to middle cerebral artery occlusion-reperfusion to evaluate the effect on stroke of the selective β1AR blocker metoprolol (12.5 mg·kg^-1 ) when injected i.v. 10 min before reperfusion.

KEY RESULTS

Magnetic resonance imaging and histopathology analysis showed that pre-reperfusion i.v. metoprolol reduced infarct size. This effect was accompanied by reduced cytotoxic oedema at 24 h and vasogenic oedema at 7 days. Metoprolol-treated rats showed reduced brain neutrophil infiltration and those which infiltrated displayed a high proportion of anti-inflammatory phenotype (N2, YM1⁺ ). Additional inflammatory models demonstrated that metoprolol specifically blocked neutrophil migration via β1AR and excluded a significant effect on the glia compartment. Consistently, metoprolol did not protect the brain in neutrophil-depleted rats upon stroke. In patients suffering an ischaemic stroke, β1AR blockade by metoprolol reduced circulating neutrophil-platelet co-aggregates.

CONCLUSIONS AND IMPLICATIONS

Our findings describe that β1AR blockade ameliorates cerebral damage by targeting neutrophils, identifying a novel therapeutic target to improve outcomes in patients with stroke. This therapeutic strategy is in the earliest stages of the translational pathway and should be further explored.

A Novel 5-Chloro-N-phenyl-1H-indole-2-carboxamide Derivative as Brain-Type Glycogen Phosphorylase Inhibitor: Potential Therapeutic Effect on Cerebral Ischemia

Brain-type glycogen phosphorylase inhibitors are potential new drugs for treating ischemic brain injury. In our previous study, we reported compound 1 as a novel brain-type glycogen phosphorylase inhibitor with cardioprotective properties. We also found that compound 1 has high blood–brain barrier permeability through the ADMET prediction website. In this study, we deeply analyzed the protective effect of compound 1 on hypoxic-ischemic brain injury, finding that compound 1 could alleviate the hypoxia/reoxygenation (H/R) injury of astrocytes by improving cell viability and reducing LDH leakage rate, intracellular glucose content, and post-ischemic ROS level. At the same time, compound 1 could reduce the level of ATP in brain cells after ischemia, improve cellular energy metabolism, downregulate the degree of extracellular acidification, and improve metabolic acidosis. It could also increase the level of mitochondrial aerobic energy metabolism during brain cell reperfusion, reduce anaerobic glycolysis, and inhibit apoptosis and the expression of apoptosis-related proteins. The above results indicated that compound 1 is involved in the regulation of glucose metabolism, can control cell apoptosis, and has protective and potential therapeutic effects on cerebral ischemia-reperfusion injury, which provides a new reference and possibility for the development of novel drugs for the treatment of ischemic brain injury.

AMPK Modulates the Metabolic Adaptation of C6 Glioma Cells in Glucose-Deprived Conditions without Affecting Glutamate Transport

Energy homeostasis in the central nervous system largely depends on astrocytes, which provide metabolic support and protection to neurons. Astrocytes also ensure the clearance of extracellular glutamate through high-affinity transporters, which indirectly consume ATP. Considering the role of the AMP-activated protein kinase (AMPK) in the control of cell metabolism, we have examined its implication in the adaptation of astrocyte functions in response to a metabolic stress triggered by glucose deprivation. We genetically modified the astrocyte-like C6 cell line to silence AMPK activity by overexpressing a dominant negative mutant of its catalytic subunit. Upon glucose deprivation, we found that C6 cells maintain stable ATP levels and glutamate uptake capacity, highlighting their resilience during metabolic stress. In the same conditions, cells with silenced AMPK activity showed a reduction in motility, metabolic activity, and ATP levels, indicating that their adaptation to stress is compromised. The rate of ATP production remained, however, unchanged by AMPK silencing, suggesting that AMPK mostly influences energy consumption during stress conditions in these cells. Neither AMPK modulation nor prolonged glucose deprivation impaired glutamate uptake. Together, these results indicate that AMPK contributes to the adaptation of astrocyte metabolism triggered by metabolic stress, but not to the regulation of glutamate transport.

Antioxidant and Neuroprotective Effects of Carnosine: Therapeutic Implications in Neurodegenerative Diseases

Neurodegenerative diseases (NDs) constitute a global challenge to human health and an important social and economic burden worldwide, mainly due to their growing prevalence in an aging population and to their associated disabilities. Despite their differences at the clinical level, NDs share fundamental pathological mechanisms such as abnormal protein deposition, intracellular Ca²⁺ overload, mitochondrial dysfunction, redox homeostasis imbalance and neuroinflammation. Although important progress is being made in deciphering the mechanisms underlying NDs, the availability of effective therapies is still scarce. Carnosine is a natural endogenous molecule that has been extensively studied during the last years due to its promising beneficial effects for human health. It presents multimodal mechanisms of action, being able to exert antioxidant, anti-inflammatory and anti-aggregate activities, among others. Interestingly, most NDs exhibit oxidative and nitrosative stress, protein aggregation and inflammation as molecular hallmarks. In this review, we discuss the neuroprotective functions of carnosine and its implications as a therapeutic strategy in different NDs. We summarize the existing works that study alterations in carnosine metabolism in Alzheimer’s disease and Parkinson’s disease, the two most common NDs. In addition, we review the beneficial effect that carnosine supplementation presents in models of such diseases as well as in aging-related neurodegeneration.

l-Carnosine Protects Against Deoxynivalenol-Induced Oxidative Stress in Intestinal Stem Cells by Regulating the Keap1/Nrf2 Signaling Pathway

SCOPE

The intestinal epithelium is nourished by various nutrients and subjected to persistent and widespread feed-derived mycotoxin stress. l-Carnosine (LC) possesses robust antioxidant activity; however, its role in protecting intestinal mucosa against deoxynivalenol (DON) is still unclear.

METHODS AND RESULTS

In this study, 300 mg kg-1 BW LC and 3 mg kg-1 BW DON are orally administered to mice either alone or in combination for 10 days to investigate the role of LC in protecting the intestine against DON. This study found that LC alleviates the growth retardation of mice and repairs the damaged jejunal structure and barrier functions under DON exposure. LC rescues the intestinal stem cells (ISCs), increases the growth advantage in enteroids derived from jejunal crypts of mice in each group ex vivo, improves the proliferation and apoptosis of intestinal cells, and promotes ISC differentiation into absorptive cells, goblet cells, and Paneth cells. Furthermore, LC activates Nrf2 signaling by binding to Keap1 to reverse the striking DON-induced increase in ROS levels.

CONCLUSION

The study findings unveil that LC potentiates the antioxidant capacity of ISCs by regulating the Keap1/Nrf2 signaling pathway, which contributes to the intestinal epithelial regeneration response to DON insult.

Effects of carnosine and hypothermia combination therapy on hypoxic-ischemic brain injury in neonatal rats

BACKGROUND

Carnosine has antioxidative and neuroprotective properties against hypoxic-ischemic (HI) brain injury. Hypothermia is used as a therapeutic tool for HI encephalopathy in newborn infants with perinatal asphyxia. However, the combined effects of these therapies are unknown.

PURPOSE

Here we investigated the effects of combined carnosine and hypothermia therapy on HI brain injury in neonatal rats.

METHODS

Postnatal day 7 (P7) rats were subjected to HI brain injury and randomly assigned to 4 groups: vehicle; carnosine alone; vehicle and hypothermia; and carnosine and hypothermia. Carnosine (250 mg/kg) was intraperitoneally administered at 3 points: immediately following HI injury, 24 hours later, and 48 hours later. Hypothermia was performed by placing the rats in a chamber maintained at 27°C for 3 hours to induce whole-body cooling. Sham-treated rats were also included as a normal control. The rats were euthanized for experiments at P10, P14, and P35. Histological and morphological analyses, in situ zymography, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assays, and immunofluorescence studies were conducted to investigate the neuroprotective effects of the various interventional treatments.

RESULTS

Vehicle-treated P10 rats with HI injury showed an increased infarct volume compared to sham-treated rats during the triphenyltetrazolium chloride staining study. Hematoxylin and eosin staining revealed that vehicle-treated P35 rats with HI injury had decreased brain volume in the affected hemisphere. Compared to the vehicle group, carnosine and hypothermia alone did not result in any protective effects against HI brain injury. However, a combination of carnosine and hypothermia effectively reduced the extent of brain damage. The results of in situ zymography, TUNEL assays, and immunofluorescence studies showed that neuroprotective effects were achieved with combination therapy only.

CONCLUSION

Carnosine and hypothermia may have synergistic neuroprotective effects against brain damage following HI injury.

Sigma 1 Receptor Modulates Optic Nerve Head Astrocyte Reactivity

Purpose

Stimulation of Sigma 1 Receptor (S1R) is neuroprotective in retina and optic nerve. S1R is expressed in both neurons and glia. The purpose of this work is to evaluate the ability of S1R to modulate reactivity responses of optic nerve head astrocytes (ONHAs) by investigating the extent to which S1R activation alters ONHA reactivity under conditions of ischemic cellular stress.

Methods

Wild type (WT) and S1R knockout (KO) ONHAs were derived and treated with vehicle or S1R agonist, (+)-pentazocine ((+)-PTZ). Cells were subjected to six hours of oxygen glucose deprivation (OGD) followed by 18 hours of re-oxygenation (OGD/R). Astrocyte reactivity responses were measured. Molecules that regulate ONHA reactivity, signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappa B (NF-kB), were evaluated.

Results

Baseline glial fibrillary acidic protein (GFAP) levels were increased in nonstressed KO ONHAs compared with WT cultures. Baseline cellular migration was also increased in nonstressed KO ONHAs compared with WT. Treatment with (+)-PTZ increased cellular migration in nonstressed WT ONHAs but not in KO ONHAs. Exposure of both WT and KO ONHAs to ischemia (OGD/R), increased GFAP levels and cellular proliferation. However, (+)-PTZ treatment of OGD/R-exposed ONHAs enhanced GFAP levels, cellular proliferation, and cellular migration in WT but not KO cultures. The (+)-PTZ treatment of WT ONHAs also enhanced the OGD/R-induced increase in cellular pSTAT3 levels. However, treatment of WT ONHAs with (+)-PTZ abrogated the OGD/R-induced rise in NF-kB(p65) activation.

Conclusions

Under ischemic stress conditions, S1R activation enhanced ONHA reactivity characteristics. Future studies should address effects of these responses on RGC survival.

Cinnamaldehyde protects against rat intestinal ischemia/reperfusion injuries by synergistic inhibition of NF-κB and p53

Our preliminary study shows that cinnamaldehyde (CA) could protect against intestinal ischemia/reperfusion (I/R) injuries, in which p53 and NF-κB p65 play a synergistic role. In this study, we conducted in vivo and in vitro experiments to verify this proposal. SD rats were pretreated with CA (10 or 40 mg · kg⁻¹ · d⁻¹, ig) for 3 days, then subjected to 1 h mesenteric ischemia followed by 2 h reperfusion. CA pretreatment dose-dependently ameliorated morphological damage and reduced inflammation evidenced by decreased TNF-α, IL-1β, and IL-6 levels and MPO activity in I/R-treated intestinal tissues. CA pretreatment also attenuated oxidative stress through restoring SOD, GSH, LDH, and MDA levels in I/R-treated intestinal tissues. Furthermore, CA pretreatment significantly reduced the expression of inflammation/apoptosis-related NF-κB p65, IKKβ, IK-α, and NF-κB p50, and downregulated apoptotic protein expression including p53, Bax, caspase-9 and caspase-3, and restoring Bcl-2, in I/R-treated intestinal tissues. We pretreated IEC-6 cells in vitro with CA for 24 h, followed by 4 h hypoxia and 3 h reoxygenation (H/R) incubation. Pretreatment with CA (3.125, 6.25, and 12.5 μmol · L⁻¹) significantly reversed H/R-induced reduction of IEC-6 cell viability. CA pretreatment significantly suppressed oxidative stress, NF-κB activation and apoptosis in H/R-treated IEC-6 cells. Moreover, CA pretreatment significantly reversed mitochondrial dysfunction in H/R-treated IEC-6 cells. CA pretreatment inhibited the nuclear translocation of p53 and NF-κB p65 in H/R-treated IEC-6 cells. Double knockdown or overexpression of p53 and NF-κB p65 caused a synergistic reduction or elevation of p53 compared with knockdown or overexpression of p53 or NF-κB p65 alone. In H/R-treated IEC-6 cells with double knockdown or overexpression of NF-κB p65 and p53, CA pretreatment caused neither further decrease nor increase of NF-κB p65 or p53 expression, suggesting that CA-induced synergistic inhibition on both NF-κB and p53 played a key role in ameliorating intestinal I/R injuries. Finally, we used immunoprecipitation assay to demonstrate an interaction between p53 and NF-κB p65, showing the basis for CA-induced synergistic inhibition. Our results provide valuable information for further studies.

Therapeutic Potential of Carnosine and Its Derivatives in the Treatment of Human Diseases

Despite significant progress in the pathogenesis, diagnosis, treatment, and prevention of cancer and neurodegenerative diseases, their occurrence and mortality are still high around the world. The resistance of cancer cells to the drugs remains a significant problem in oncology today, while in the case of neuro-degenerative diseases, therapies reversing the process are still yet to be found. Furthermore, it is important to seek new chemotherapeutics reversing side effects of currently used drugs or helping them perform their function to inhibit progression of the disease. Carnosine, a dipeptide constisting of β-alanine and l-histidine, has a variety of functions to mention: antioxidant, antiglycation, and reducing the toxicity of metal ions. It has therefore been proposed to act as a therapeutic agent for many pathological states. The aim of this paper was to find if carnosine and its derivatives can be helpful in treating various diseases. Literature search presented in this review includes review and original papers found in SciFinder, PubMed, and Google Scholar. Searches were based on substantial keywords concerning therapeutic usage of carnosine and its derivatives in several diseases including neurodegenerative disorders and cancer. In this paper, we review articles and find that carnosine and its derivatives are potential therapeutic agents in many diseases including cancer, neurodegenerative diseases, diabetes, and schizophrenia. Carnosine and its derivatives can be used in treating neurodegenerative diseases, cancer, diabetes, or schizophrenia, although their usage is limited. Therefore, there's an urge to synthesize and analyze new substances, overcoming the limitation of carnosine itself.

The glucagon-like peptide-1 receptor agonist reduces inflammation and blood-brain barrier breakdown in an astrocyte-dependent manner in experimental stroke

Background

Preserving the integrity of the blood-brain barrier (BBB) is beneficial to avoid further brain damage after acute ischemic stroke (AIS). Astrocytes, an important component of the BBB, promote BBB breakdown in subjects with AIS by secreting inflammatory factors. The glucagon-like peptide-1 receptor (GLP-1R) agonist exendin-4 (Ex-4) protects the BBB and reduces brain inflammation from cerebral ischemia, and GLP-1R is expressed on astrocytes. However, the effect of Ex-4 on astrocytes in subjects with AIS remains unclear.

Methods

In the present study, we investigated the effect of Ex-4 on astrocytes cultured under oxygen-glucose deprivation (OGD) plus reoxygenation conditions and determined whether the effect influences bEnd.3 cells. We used various methods, including permeability assays, western blotting, immunofluorescence staining, and gelatin zymography, in vitro and in vivo.

Results

Ex-4 reduced OGD-induced astrocyte-derived vascular endothelial growth factor (VEGF-A), matrix metalloproteinase-9 (MMP-9), chemokine monocyte chemoattractant protein-1 (MCP-1), and chemokine C-X-C motif ligand 1 (CXCL-1). The reduction in astrocyte-derived VEGF-A and MMP-9 was related to the increased expression of tight junction proteins (TJPs) in bEnd.3 cells. Ex-4 improved neurologic deficit scores, reduced the infarct area, and ameliorated BBB breakdown as well as decreased astrocyte-derived VEGF-A, MMP-9, CXCL-1, and MCP-1 levels in ischemic brain tissues from rats subjected to middle cerebral artery occlusion. Ex-4 reduced the activation of the JAK2/STAT3 signaling pathway in astrocytes following OGD.

Conclusion

Based on these findings, ischemia-induced inflammation and BBB breakdown can be improved by Ex-4 through an astrocyte-dependent manner.

TRPV1 translocated to astrocytic membrane to promote migration and inflammatory infiltration thus promotes epilepsy after hypoxic ischemia in immature brain

BACKGROUND

Neonatal hypoxic-ischemic brain damage (HIBD), a leading cause of neonatal mortality, has intractable sequela such as epilepsy that seriously affected the life quality of HIBD survivors. We have previously shown that ion channel dysfunction in the central nervous system played an important role in the process of HIBD-induced epilepsy. Therefore, we continued to validate the underlying mechanisms of TRPV1 as a potential target for epilepsy.

METHODS

Neonatal hypoxic ischemia and oxygen-glucose deprivation (OGD) were used to simulate HIBD in vivo and in vitro. Primarily cultured astrocytes were used to assess the expression of TRPV1, glial fibrillary acidic protein (GFAP), cytoskeletal rearrangement, and inflammatory cytokines by using Western blot, q-PCR, and immunofluorescence. Furthermore, brain electrical activity in freely moving mice was recorded by electroencephalography (EEG). TRPV1 current and neuronal excitability were detected by whole-cell patch clamp.

RESULTS

Astrocytic TRPV1 translocated to the membrane after OGD. Mechanistically, astrocytic TRPV1 activation increased the inflow of Ca²⁺, which promoted G-actin polymerized to F-actin, thus promoted astrocyte migration after OGD. Moreover, astrocytic TRPV1 deficiency decreased the production and release of pro-inflammatory cytokines (TNF, IL-6, IL-1β, and iNOS) after OGD. It could also dramatically attenuate neuronal excitability after OGD and brain electrical activity in HIBD mice. Behavioral testing for seizures after HIBD revealed that TRPV1 knockout mice demonstrated prolonged onset latency, shortened duration, and decreased seizure severity when compared with wild-type mice.

CONCLUSIONS

Collectively, TRPV1 promoted astrocyte migration thus helped the infiltration of pro-inflammatory cytokines (TNF, IL-1β, IL-6, and iNOS) from astrocytes into the vicinity of neurons to promote epilepsy. Our study provides a strong rationale for astrocytic TRPV1 to be a therapeutic target for anti-epileptogenesis after HIBD.

The Potential of Carnosine in Brain-Related Disorders: A Comprehensive Review of Current Evidence

Neurological, neurodegenerative, and psychiatric disorders represent a serious burden because of their increasing prevalence, risk of disability, and the lack of effective causal/disease-modifying treatments. There is a growing body of evidence indicating potentially favourable effects of carnosine, which is an over-the-counter food supplement, in peripheral tissues. Although most studies to date have focused on the role of carnosine in metabolic and cardiovascular disorders, the physiological presence of this di-peptide and its analogues in the brain together with their ability to cross the blood-brain barrier as well as evidence from in vitro, animal, and human studies suggest carnosine as a promising therapeutic target in brain disorders. In this review, we aim to provide a comprehensive overview of the role of carnosine in neurological, neurodevelopmental, neurodegenerative, and psychiatric disorders, summarizing current evidence from cell, animal, and human cross-sectional, longitudinal studies, and randomized controlled trials.

Carnosine Suppresses Human Colorectal Cell Migration and Intravasation by Regulating EMT and MMP Expression

Carnosine is an endogenous dipeptide found in the vertebrate skeletal muscles that is usually obtained through the diet. To investigate the mechanism by which carnosine regulates the migration and intravasation of human colorectal cancer (CRC) cells, we used cultured HCT-116 cells as an experimental model in this study. We examined HCT-116 cell migratory and intravasive abilities and expression of epithelial-mesenchymal transition (EMT)-associated molecules and matrix metalloproteinases (MMPs) after carnosine treatment. The results showed that both migration and invasion were inhibited in cells treated with carnosine. We found significant decreases in Twist-1 protein levels and increases in E-cadherin protein levels in HCT-116 cells after carnosine exposure. Although plasminogen activator (uPA) and MMP-9 mRNA and protein levels were decreased, TIMP-1 mRNA and protein levels were increased. Furthermore, the cytosolic levels of phosphorylated I κ B (p-I κ B) and NF- κ B DNA-binding activity were reduced after carnosine treatment. These results indicate that carnosine inhibits the migration and intravasation of human CRC cells. The regulatory mechanism may occur by suppressing NF- κ B activity and modulating MMP and EMT-related gene expression in HCT-116 cells.

The Role of Mast Cells in Stroke

Mast cells (MCs) are densely granulated perivascular resident cells of hematopoietic origin. Through the release of preformed mediators stored in their granules and newly synthesized molecules, they are able to initiate, modulate, and prolong the immune response upon activation. Their presence in the central nervous system (CNS) has been documented for more than a century. Over the years, MCs have been associated with various neuroinflammatory conditions of CNS, including stroke. They can exacerbate CNS damage in models of ischemic and hemorrhagic stroke by amplifying the inflammatory responses and promoting brain–blood barrier disruption, brain edema, extravasation, and hemorrhage. Here, we review the role of these peculiar cells in the pathophysiology of stroke, in both immature and adult brain. Further, we discuss the role of MCs as potential targets for the treatment of stroke and the compounds potentially active as MCs modulators.

Pivotal role of carnosine in the modulation of brain cells activity: Multimodal mechanism of action and therapeutic potential in neurodegenerative disorders

Carnosine (β-alanyl-l-histidine), a dipeptide, is an endogenous antioxidant widely distributed in excitable tissues like muscles and the brain. Although discovered more than a hundred years ago and having been extensively studied in the periphery, the role of carnosine in the brain remains mysterious. Carnosinemia, a rare metabolic disorder with increased levels of carnosine in urine and low levels or absence of carnosinase in the blood, is associated with severe neurological symptoms in humans. This review deals with the role of carnosine in the brain in both physiological and pathological conditions, with a focus on preclinical evidence suggesting a high therapeutic potential of carnosine in neurodegenerative disorders. We review carnosine and carnosinemia's discoveries and the extensive research on the role and benefits of carnosine in the periphery. We then turn to carnosine's biochemistry and distribution in the brain. Using an array of recent observations as a foundation, we draw a parallel with the role of carnosine in muscles and speculate on the role of carnosine in promoting the metabolic support of neurons by glial cells. Finally, carnosine has been shown to exert a multimodal activity including inhibition of protein cross-linking and aggregation of amyloid-β and related proteins, free radical generation, nitric oxide detoxification, and an anti-inflammatory activity. It could thus play an important role in the prevention and treatment of neurodegenerative diseases such as Alzheimer's disease. We discuss the potential of carnosine in this context and speculate on new preclinical research directions.

Carnosine selectively inhibits migration of IDH-wildtype glioblastoma cells in a co-culture model with fibroblasts

Background

Glioblastoma (GBM) is a tumor of the central nervous system. After surgical removal and standard therapy, recurrence of tumors is observed within 6–9 months because of the high migratory behavior and the infiltrative growth of cells. Here, we investigated whether carnosine (β-alanine-l-histidine), which has an inhibitory effect on glioblastoma proliferation, may on the opposite promote invasion as proposed by the so-called “go-or-grow concept”.

Methods

Cell viability of nine patient derived primary (isocitrate dehydrogenase wildtype; IDH1R132H non mutant) glioblastoma cell cultures and of eleven patient derived fibroblast cultures was determined by measuring ATP in cell lysates and dehydrogenase activity after incubation with 0, 50 or 75 mM carnosine for 48 h. Using the glioblastoma cell line T98G, patient derived glioblastoma cells and fibroblasts, a co-culture model was developed using 12 well plates and cloning rings, placing glioblastoma cells inside and fibroblasts outside the ring. After cultivation in the presence of carnosine, the number of colonies and the size of the tumor cell occupied area were determined.

Results

In 48 h single cultures of fibroblasts and tumor cells, 50 and 75 mM carnosine reduced ATP in cell lysates and dehydrogenase activity when compared to the corresponding untreated control cells. Co-culture experiments revealed that after 4 week exposure to carnosine the number of T98G tumor cell colonies within the fibroblast layer and the area occupied by tumor cells was reduced with increasing concentrations of carnosine. Although primary cultured tumor cells did not form colonies in the absence of carnosine, they were eliminated from the co-culture by cell death and did not build colonies under the influence of carnosine, whereas fibroblasts survived and were healthy.

Conclusions

Our results demonstrate that the anti-proliferative effect of carnosine is not accompanied by an induction of cell migration. Instead, the dipeptide is able to prevent colony formation and selectively eliminates tumor cells in a co-culture with fibroblasts.

Electronic supplementary material

The online version of this article (10.1186/s12935-018-0611-2) contains supplementary material, which is available to authorized users.