Anti-inflammatory effects of lipoic acid through inhibition of GSK-3β in lipopolysaccharide-induced BV-2 microglial cells

Gliotoxicity and Glioprotection: the Dual Role of Glial Cells

Glial cells (astrocytes, oligodendrocytes and microglia) are critical for the central nervous system (CNS) in both physiological and pathological conditions. With this in mind, several studies have indicated that glial cells play key roles in the development and progression of CNS diseases. In this sense, gliotoxicity can be referred as the cellular, molecular, and neurochemical changes that can mediate toxic effects or ultimately lead to impairment of the ability of glial cells to protect neurons and/or other glial cells. On the other hand, glioprotection is associated with specific responses of glial cells, by which they can protect themselves as well as neurons, resulting in an overall improvement of the CNS functioning. In addition, gliotoxic events, including metabolic stresses, inflammation, excitotoxicity, and oxidative stress, as well as their related mechanisms, are strongly associated with the pathogenesis of neurological, psychiatric and infectious diseases. However, glioprotective molecules can prevent or improve these glial dysfunctions, representing glial cells-targeting therapies. Therefore, this review will provide a brief summary of types and functions of glial cells and point out cellular and molecular mechanisms associated with gliotoxicity and glioprotection, potential glioprotective molecules and their mechanisms, as well as gliotherapy. In summary, we expect to address the relevance of gliotoxicity and glioprotection in the CNS homeostasis and diseases.

Alpha lipoic acid with pulsed radiofrequency in treatment of chronic lumbosacral radicular pain: A prospective, randomized study

BACKGROUND

The effect of adding alpha lipoic acid (ALA) to pulsed radiofrequency (PRF) for treatment of lumbar-sacral pain was evaluated.

OBJECTIVE

to evaluate the effect of using ALA as an adjuvant therapy with PRF for treatment of chronic lumbosacral radicular pain caused by herniated disc.

METHODS

One hundred twenty patients with lumbo-sacral radicular pain allocated into 2 groups. Group I: treated with PRF at 42°C for 120 seconds. Group II: treated as in group I, plus oral ALA 600 mg (Thiotacid 600 mg, EVA PHARMA, Egypt) three times per day (1800 mg/day) for 3 weeks then 600 mg once daily for 2 weeks. The lumbo-sacral radicular pain evaluated using the numerical rating pain score and Oswestry Disability Index.

RESULTS

Success rate was significantly higher in group II at 3 and 6 months after intervention. The median values of the numerical rating pain score and the Oswestry Disability Index were significantly lower in group II with no significant difference in Epworth Sleepiness Scale. No major complications were reported in both groups.

CONCLUSION

The current study supports the use of ALA with PRF on the dorsal root ganglion for treating lumbosacral radicular pain.

Lithium inhibits NF-κB nuclear translocation and modulate inflammation profiles in Rift valley fever virus-infected Raw 264.7 macrophages

Introduction

Rift Valley fever virus (RVFV) is a zoonotic life-threatening viral infection endemic across sub-Saharan African countries and the Arabian Peninsula; however, there is a growing panic of its spread to non-endemic regions. This viral infection triggers a wide spectrum of symptoms that span from fibril illnesses to more severe symptoms such as haemorrhagic fever and encephalitis. These severe symptoms have been associated with dysregulated immune response propagated by the virulence factor, non-structural protein (NSs). Thus, this study investigates the effects of lithium on NF-κB translocation and RFVF-induced inflammation in Raw 264.7 macrophages.

Methods

The supernatant from RVFV-infected Raw 264.7 cells, treated with lithium, was examined using an ELISA assay kit to measure levels of cytokines and chemokines. The H₂DCF-DA and DAF-2 DA florigenic assays were used to determine the levels of ROS and RNS by measuring the cellular fluorescence intensity post RVFV-infection and lithium treatment. Western blot and immunocytochemistry assays were used to measure expression levels of the inflammatory proteins and cellular location of the NF-κB, respectively.

Results

Lithium was shown to stimulate interferon-gamma (IFN-γ) production as early as 3 h pi. Production of the secondary pro-inflammatory cytokine and chemokine, interleukin-6 (IL-6) and regulated on activation, normal T cell expressed and secreted (RANTES), were elevated as early as 12 h pi. Treatment with lithium stimulated increase of production of tumor necrosis factor-alpha (TNF-α) and Interleukin-10 (IL-10) in RVFV-infected and uninfected macrophages as early as 3 h pi. The RVFV-infected cells treated with lithium displayed lower ROS and RNS production as opposed to lithium-free RVFV-infected control cells. Western blot analyses demonstrated that lithium inhibited iNOS expression while stimulating expression of heme oxygenase (HO) and IκB in RVFV-infected Raw 264.7 macrophages. Results from immunocytochemistry and Western blot assays revealed that lithium inhibits NF-κB nuclear translocation in RVFV-infected cells compared to lithium-free RVFV-infected cells and 5 mg/mL LPS controls.

Conclusion

This study demonstrates that lithium inhibits NF-kB nuclear translocation and modulate inflammation profiles in RVFV-infected Raw 264.7 macrophage cells.

Glycogen Synthase Kinase 3β Modulates the Inflammatory Response Activated by Bacteria, Viruses, and Parasites

Knowledge of glycogen synthase kinase 3β (GSK3β) activity and the molecules identified that regulate its function in infections caused by pathogenic microorganisms is crucial to understanding how the intensity of the inflammatory response can be controlled in the course of infections. In recent years many reports have described small molecular weight synthetic and natural compounds, proteins, and interference RNA with the potential to regulate the GSK3β activity and reduce the deleterious effects of the inflammatory response. Our goal in this review is to summarize the most recent advances on the role of GSK3β in the inflammatory response caused by bacteria, bacterial virulence factors (i.e. LPS and others), viruses, and parasites and how the regulation of its activity, mainly its inhibition by different type of molecules, modulates the inflammation.

Lipoic Acid and Fish Oil Combination Potentiates Neuroinflammation and Oxidative Stress Regulation and Prevents Cognitive Decline of Rats After Sepsis

Sepsis causes organ dysfunction due to an infection, and it may impact the central nervous system. Neuroinflammation and oxidative stress are related to brain dysfunction after sepsis. Both processes affect microglia activation, neurotrophin production, and long-term cognition. Fish oil (FO) is an anti-inflammatory compound, and lipoic acid (LA) is a universal antioxidant substance. They exert neuroprotective roles when administered alone. We aimed at determining the effect of FO+LA combination on microglia activation and brain dysfunction after sepsis. Microglia cells from neonatal pups were co-treated with lipopolysaccharide (LPS) and FO or LA, alone or combined, for 24 h. Cytokine levels were measured. Wistar rats were subjected to sepsis by cecal ligation and perforation (CLP) and treated orally with FO, LA, or FO+LA. At 24 h after surgery, the hippocampus, prefrontal cortex, and total cortex were obtained and assayed for levels of cytokines, myeloperoxidase (MPO) activity, protein carbonyls, superoxide dismutase (SOD), and catalase (CAT) activity. At 10 days after surgery, brain-derived neurotrophic factor (BDNF) levels were determined and behavioral tests were performed. The combination diminished in vitro levels of pro-inflammatory cytokines. The combination reduced TNF-α in the cortex, IL-1β in the prefrontal cortex, as well as MPO activity, and decreased protein carbonyls formation in all structures. The combination enhanced catalase activity in the prefrontal cortex and hippocampus, elevated BDNF levels in all structures, and prevented behavioral impairment. In summary, the combination was effective in preventing cognitive damage by reducing neuroinflammation and oxidative stress and increasing BDNF levels.

BIO alleviates inflammation through inhibition of GSK-3β in a rat model of intracerebral hemorrhage

OBJECTIVE

Inflammation plays a key role in secondary brain damage following intracerebral hemorrhage (ICH). Glycogen synthase kinase-3β (GSK-3β) plays a strong proinflammatory role in many CNS diseases, including stroke. The present study was undertaken to examine the effects of 6-bromoindirubin-3'-oxime (BIO), a specific inhibitor of GSK-3β, on inflammation in ICH rats.

METHODS

An ICH rat model was induced by autologous whole-blood injection into the striatum. First, 10, 20, 40, 60, 80, or 100 μg/kg BIO was applied to ICH animals to determine an optimal dosage for producing sufficient GSK-3β inhibition in rat ipsilateral hippocampus by Western blotting. Second, 40 μg/kg BIO was applied to ICH rats for 1, 3, 7, or 14 days, respectively, to determine a suitable intervention time course of BIO by Western blotting analysis on GSK-3β. Third, Western blotting and enzyme-linked immunosorbent assay were used for quantification of inflammation-related factors upstream or downstream of GSK-3β in rat ipsilateral hippocampus. Then, immunohistochemical staining was applied to detect activated microglia and apoptotic cells in rat ipsilateral hippocampus. Last, neurobehavioral tests were performed to assess the sensorimotor impairments in the ICH rats.

RESULTS

The results show that BIO 1) blocked GSK-3βTyr216 phosphorylation/activation, thus stabilizing β-catenin, increasing upstream brain-derived neurotrophic factor and downstream heat shock protein 70 levels, and decreasing the levels of nuclear factor-κB p65 and cyclooxygenase 2; 2) decreased the levels of the proinflammatory cytokines tumor necrosis factor-α and interleukin (IL)-1β and IL-6 and elevated the level of antiinflammatory cytokine IL-10; 3) inhibited microglia activation and cell apoptosis; and 4) improved the sensorimotor deficits of ICH rats.

CONCLUSIONS

BIO posttreatment inhibited microglia activation, prevented inflammation and hippocampal cell death, and ameliorated functional and morphological outcomes in a rat ICH model through inactivation of GSK-3β.

Effects of lipoic acid on primary murine microglial cells

The anti-oxidant lipoic acid (LA) is beneficial in murine models of multiple sclerosis (MS) and has recently been shown to slow brain atrophy in secondary progressive MS. The mechanism of these effects by LA is incompletely understood but may involve effects on microglia. The objective of this study is to understand how LA affects microglial cells. We cultured primary microglial cells from C57BL/6 adult mice brains and stimulated the cells with lipopolysaccharide (LPS) and interferon gamma (IFN-γ) in the presence or absence of LA. We demonstrate the inhibition of phagocytosis, rearrangement of actin, and formation of membrane blebs in stimulated microglia in the presence of LA. These experiments suggest that LA causes changes in microglial actin, which may lead to alterations in phagocytosis, mobility, and migration.

Alpha-lipoic acid (ALA) supplementation effect on glycemic and inflammatory biomarkers: A Systematic Review and meta- analysis

BACKGROUND & AIMS

Several randomized clinical trials (RCTs) have investigated the effect of Alpha - Lipoic Acid (ALA) supplementation on metabolic parameters, with conflicting results. Therefore, the present study assessed the effect of ALA on some glycemic and inflammatory parameters.

METHODS

A comprehensive literature search was conducted up from inception to July 2018 on PubMed, Scopus, Cochrane databases, Google Scholar, ProQuest, Web of Science, and Embase. From among eligible trials, 41 articles were selected for the meta-analysis. Two reviewers independently assessed the risk of bias and extracted data from the included studies. Meta-analyses using the random-effects model were performed to analyze the data.

RESULTS

Based on the Cochrane risk of bias tool, 19 articles had a good quality, 16 trials had a poor quality and 6 trials had a fair quality. The results demonstrated the significant effect of ALA on Fasting Blood Sugar (FBS) (weighted mean difference (WMD)) = -6.57, 95% confidence interval (CI: -11.91 to -1.23, P = 0.016), Hemoglobin A1c (HbA1c) (WMD = -0.35, 95% CI: -0.55 to -0.15, P = 0.004), Tumor Necrosis Factor Alpha (TNF-α) (WMD = -1.57, 95% CI: -2.29 to -0.85, P < 0.05), Interleukin 6 levels (IL-6) (WMD = -1.15, 95% CI: -1.58 to -0.72, P < 0.001), and C-reactive protein (CRP) (WMD = -0.31, 95% CI: -0.47 to -0.16, P > 0.001). No effect was detected for ALA on insulin and the homeostatic model assessment of insulin resistance (HOMA-IR).

CONCLUSIONS

These findings suggest that ALA is a viable supplement to improve some of the glycemic and inflammatory biomarkers.

Rational Basis for Nutraceuticals in the Treatment of Glaucoma

BACKGROUND

Glaucoma, the second leading cause of blindness worldwide, is a chronic optic neuropathy characterized by progressive retinal ganglion cell (RGC) axons degeneration and death. Primary open-angle glaucoma (OAG), the most common type, is often associated with increased intraocular pressure (IOP), however other factors have been recognized to partecipate to the patogenesis of the optic neuropathy. IOP-independent mechanisms that contribute to the glaucoma-related neurodegeneration include oxidative stress, excitotoxicity, neuroinflammation, and impaired ocular blood flow. The involvement of several and diverse factors is one of the reasons for the progression of glaucoma observed even under efficient IOP control with the currently available drugs.

METHODS

Current research and online content related to the potential of nutritional supplements for limiting retinal damage and improving RGC survival is reviewed.

RESULTS

Recent studies have suggested a link between dietary factors and glaucoma risk. Particularly, some nutrients have proven capable of lowering IOP, increase circulation to the optic nerve, modulate excitotoxicity and promote RGC survival. However, the lack of clinical trials limit their current therapeutic use. The appropriate use of nutraceuticals that may be able to modify the risk of glaucoma may provide insight into glaucoma pathogenesis and decrease the need for, and therefore the side effects from, conventional therapies.

CONCLUSION

The effects of nutrients with anti-oxidant and neuroprotective properties are of great interest and nutraceuticals may offer some therapeutic potential although a further rigorous evaluation of nutraceuticals in the treatment of glaucoma is needed to determine their safety and efficacy.

Dickkopf-1 may regulate bone coupling by attenuating wnt/β-catenin signaling in chronic apical periodontitis

OBJECTIVE

Alveolar bone loss is a common outcome of chronic apical periodontitis. In this study, we investigated the involvement of the Dickkopf-1-Wnt/β-catenin signaling pathway in the attenuation of osteogenic differentiation induced by Escherichia coli lipopolysaccharide, and we evaluated the use of Dickkopf-1 inhibitor and Dickkopf-1 recombinant protein to reverse bone loss in different phases of osteogenic differentiation.

METHODS

MC3T3-E1 cells grown in osteogenic medium were treated with Escherichia coli lipopolysaccharide for 24h during osteogenic induction on days 0, 1, 7, 14 and 21. Dickkopf-1 siRNA was added on days 0 and 1, and Dickkopf-1 recombinant was added on days 7, 14, and 21. Quantitative real-time PCR, Western blotting and alkaline phosphatase activity assays were performed to measure osteogenic marker expression and Wnt/β-catenin signaling. A rat apical periodontitis model was used to further evaluate the function of Dickkopf-1 in relation to bone loss.

RESULTS

MC3T3-E1 cells treated with Escherichia coli lipopolysaccharide showed decreased mRNA expression of osteogenic markers. Wnt/β-catenin signaling was also inhibited, and Dickkopf-1 showed corresponding variations as quantified by Western blotting. Using Dickkopf-1 inhibitor or Dickkopf-1 recombinant protein at different phases of osteogenic differentiation in vitro partially reversed the decrease in osteogenic marker expression. The rat apical periodontitis model indicated that the Dickkopf-1 inhibitor could restore bone loss in the periapical area in vivo.

CONCLUSIONS

Dickkopf-1 may play a key regulatory role in determining the outcome for bone in inflammatory environments, and modulating the Wnt/β-catenin signaling pathway via Dickkopf-1 inhibitor or recombinant protein may provide a potential therapeutic option to prevent bone destruction in endodontic disease.

Lipoic acid functionalized SiO2@Ag nanoparticles. Synthesis, characterization and evaluation of biological activity

A novel nanocomposite was obtained through the covalent immobilization of lipoic acid on the surface of silver nanoparticles-decorated silica nanoparticles (SiO₂@Ag). The hybrid organic - inorganic material obtained was characterized by Fourier transform infrared spectroscopy, thermal analysis, scanning and transmision electron microscopy, X-ray photoelectron spectroscopy and UV-Visible spectroscopy. Its antioxidant, cytotoxic, antimicrobial activity and influence on mammalian cells cycle were evaluated. The results of this study have shown that the functionalization of SiO₂@Ag with lipoic acid resulted in a composite with increased specificity of interaction with different mammalian cell lines and antioxidant activity, but with decreased cytotoxicity and antimicrobial properties. Therefore, the SiO₂@Ag functionalized with lipoic acid could be successfully used in certain concentrations to modulate the cell cycle, in order to obtain the desired anti-proliferative or stimulatory therapeutic effect.

Necroptosis in microglia contributes to neuroinflammation and retinal degeneration through TLR4 activation

Inflammation has emerged to be a critical mechanism responsible for neural damage and neurodegenerative diseases. Microglia, the resident innate immune cells in retina, are implicated as principal components of the immunological insult to retinal neural cells. The involvement of microglia in retinal inflammation is complex and here we propose for the first time that necroptosis in microglia triggers neuroinflammation and exacerbates retinal neural damage and degeneration. We found microglia experienced receptor-interacting protein kinase 1 (RIP1)- and RIP3-dependent necroptosis not only in the retinal degenerative rd1 mice, but also in the acute retinal neural injury mice. The necroptotic microglia released various pro-inflammatory cytokines and chemokines, such as tumor necrosis factor-α and chemokine (C-C motif) ligand 2, which orchestrated the retinal inflammation. Importantly, necroptosis blockade using necrostatin-1 could suppress microglia-mediated inflammation, rescue retinal degeneration or prevent neural injury in vivo. Meanwhile, cultured microglia underwent RIP1/3-mediated necroptosis and the necroptotic microglia produced large amounts of pro-inflammatory cytokines in response to lipopolysaccharide or oxidative stress in vitro. Mechanically, TLR4 deficiency ameliorated microglia necroptosis with decreased expression levels of machinery molecules RIP1 and RIP3, and suppressed retinal inflammation, suggesting that TLR4 signaling was required in microglia necroptosis-mediated inflammation. Thus, we proposed that microglia experienced necroptosis through TLR4 activation, promoting an inflammatory response that serves to exacerbate considerable neural damage and degeneration. Necroptosis blockade therefore emerged as a novel therapeutic strategy for tempering microglia-mediated neuroinflammation and ameliorating neural injury and neurodegenerative diseases.

Time Course Effect of R-Alpha-Lipoic Acid on Cellular Metabolomics in Cultured Hepatoma Cells

Alpha-lipoic acid (LA) is a powerful antioxidant. LA has two enantiomers, R(+)-LA (R-LA) and S(-)-LA (S-LA). Of these, R-LA is naturally occurring and an essential cofactor in energy metabolism. R-LA treatment has been reported to affect glucose metabolism in rat hepatoma cells. This study analyzed the time course of metabolite levels in LA-treated cultured H4IIEC3 rat hepatoma cells, including a specific evaluation of the effect of R-LA and the enantioselectivity of LA. Principal component analysis showed that this experiment was well designed to observe enantioselectivity. R-LA treatment was found to inhibit the glycolysis and Thr-Gly-Ser pathways, as well as lactic acid production, leading to the inhibition of gluconeogenesis in starved H4IIEC3 cells. This study may provide mechanistic insight into how R-LA induces apoptosis in hepatoma cells.

Phosalone-induced inflammation and oxidative stress in the colon: Evaluation and treatment

AIM

To investigate the side effects of phosalone on intestinal cells and to evaluate benefits of ellagic acid (EA) as a remedy.

METHODS

In order to conduct an in vivo study, a rat model was used. The rats were divided into ten groups based on the materials used in the experiment and their dosage. The first group was fed normally. The second group was administered EA through gavage. Next Four groups were given (1/3, 1/5, 1/10, 1/20) LD50 phosalone; an organophosphorus compound. The last four groups received (1/3, 1/5, 1/10, 1/20) LD50 phosalone and of EA. After one month, the rats were sacrificed and their colon cells were examined to evaluate the level of inflammation, proteins and oxidative stress markers.

RESULTS

The results of this research show that phosalone elevates oxidative stress and changes the level of tumor necrosis factor-a (TNF-α), interlukin-6β (IL-6β) and nuclear factor (NF)-κB proteins. EA administration reduced phosalone toxicity and changed oxidative stress and inflammatory markers for all phosalone doses. Overall changes in reduction of TNF-α (230.47 ± 16.55 pg/mg protein vs 546.43 ± 45.24 pg/mg protein, P < 0.001), IL-6β (15.85 ± 1.03 pg/mg protein vs 21.55 ± 1.3 pg/mg protein, P < 0.05), and NF-κB (32.47 ± 4.85 pg/mg protein vs 51.41 ± 0.71 pg/mg protein, P < 0.05) manifest that the efficacy of EA is more viable for 1/3 LD50 dose of phosalone. Furthermore, EA is effective to counteract the negative outcomes of oxidative stress. When EA was used to treat 1/3 LD50 of phosalone's side effects, it improved the level of AChE activity (48.5% ± 6% vs 25% ± 7%, P < 0.05), TTM (0.391 ± 0.008 mmol/L vs 0.249 ± 0.032 mmol/L, P < 0.05), FRAP (46.04 ± 5.005 μmol/L vs 18.22 ± 1.9 μmol/L, P < 0.01) and MPO (0.222 ± 0.019 U/mg protein vs 0.387 ± 0.04 U/mg protein, P < 0.05).

CONCLUSION

This research highlights that EA is effective to alleviate the side effects of phosalone by reducing the level of oxidative stress and inflammatory proteins.

Alpha-lipoic acid exerts anti-inflammatory effects on lipopolysaccharide-stimulated rat mesangial cells via inhibition of nuclear factor kappa B (NF-κB) signaling pathway

Sepsis is often initiated by invasive infection, characterized by overwhelming induction of pro-inflammatory cytokines. The incidence and mortality of sepsis and the associated development of acute kidney injury (AKI) remain high, and lines of research into potential treatments are needed. This study was conducted to investigate effects of alpha-lipoic acid (ALA) on septic AKI in vitro. ALA of 200 or 400 μM was used to pretreat rat HBZY-1 mesangial cells before commencement of 1 μg/mL lipopolysaccharide (LPS). Our data indicated that ALA pretreatment reduced LPS-stimulated release of inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α), interleukin (IL)-1 beta (IL-1β), as well as IL-6, in HBZY-1 cell supernatant. Moreover, LPS-induced expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) was inhibited by ALA pretreatment, and consequently, the secretion levels of their respective enzymatic products prostaglandin E2 (PGE2) and nitric oxide (NO) were significantly decreased. LPS-enhanced phosphorylation of nuclear factor kappa B (NF-κB) inhibitor alpha (IκBα) and IκB kinase alpha/beta (IKKα/β) and nuclear translocation of NF-κB subunit p65 in HBZY-1 cells were inhibited by ALA pretreatment. Additionally, the NF-κB inhibitor N-acetylcysteine (NAC) exerted similar inhibitory effects as ALA on COX-2 and iNOS expression. In summary, our study demonstrates that ALA mitigates LPS-induced inflammatory responses in rat mesangial cells probably via inhibition of NF-κB signaling pathway, suggesting a therapeutic potential of ALA in AKI related to sepsis.

Lipoic acid protects dopaminergic neurons in LPS-induced Parkinson's disease model

Parkinson's disease (PD) is a chronic neurodegenerative disease of the central nervous system (CNS), characterized by a loss of dopaminergic neurons, which is thought to be caused by both genetic and environmental factors. Recent findings suggest that neuroinflammation may be a pathogenic factor in the onset and progression of sporadic PD. Here we explore the potential therapeutic effect of lipoic acid (LA) on a lipolysaccharide (LPS)-induced inflammatory PD model. Our results for the first time showed that LA administration improved motor dysfunction, protected dopaminergic neurons loss, and decreased α-synuclein accumulation in the substantia nigra (SN) area of brain. Further, LA inhibited the activation of nuclear factor-κB (NF-κB) and expression of pro-inflammatory molecules in M1 microglia. Taken together, these results suggest that LA may exert a profound neuroprotective effect and is thus a promising anti-neuroinflammatory and anti-oxidative agent for halting the progression of PD. Interventions aimed at either blocking microglia-derived inflammatory mediators or modulating the polarization of microglia may be potentially useful therapies that are worth further investigation.

Lipoic acid and N-acetylcysteine prevent ammonia-induced inflammatory response in C6 astroglial cells: The putative role of ERK and HO1 signaling pathways

Hyperammonemia induces significant changes in the central nervous system (CNS) in direct association with astroglial functions, such as oxidative damage, glutamatergic excitotoxicity, and impaired glutamine synthetase (GS) activity and pro-inflammatory cytokine release. Classically, lipoic acid (LA) and N-acetylcysteine (NAC) exhibit antioxidant and anti-inflammatory activities by increasing glutathione (GSH) biosynthesis and decreasing pro-inflammatory mediator levels in glial cells. Thus, we evaluated the protective effects of LA and NAC against ammonia cytotoxicity in C6 astroglial cells. Ammonia decreased GSH levels and increased cytokine release and NFκB transcriptional activation. LA and NAC prevented these effects by the modulation of ERK and HO1 pathways. Taken together, these observations show that LA and NAC prevent the ammonia-induced inflammatory response.

Lipopolysaccharide directly stimulates Th17 differentiation in vitro modulating phosphorylation of RelB and NF-κB1

Toll-like receptors (TLRs) recognize a wide range of pathogen-associated molecular patterns (PAMP) and are preferentially expressed in innate immune cells. TLR-mediated activation of these cells activates the adaptive immune system. However, it has become clear that TLRs are not only expressed but also functionally active in CD4 T cells. The intestines are continuously exposed to TLR ligands, including lipopolysaccharide (LPS), a TLR4 ligand, and TLR4 is expressed higher in Th17 cells than Th1 and Th2 cells. In addition, development of Th17 cells in the gut mucosa is more dependent on gut microbiota than Th1, Th2, and Treg. Thus, we examined whether LPS directly regulates Th17 differentiation. LPS directly stimulated Th17 differentiation in vitro. In Th17 cells, LPS increased phosphorylation of NF-κB1, resulting in an increase of p50, the processed form of NF-κB1, whereas it decreased phosphorylation of RelB, leading to the up-regulation of RelB. Subcutaneous injection of LPS increased the frequency of IL-17 producing cells in inguinal lymph nodes, worsening experimental autoimmune encephalomyelitis (EAE). Additionally, expression of TLR1, TLR2, TLR4, and TLR5 was reduced upon T cell activation and LPS showed modest effect on TLR4 expression. These findings provide the first evidence that TLR4 activation directly regulate Th17 differentiation.

Alpha-lipoic acid enhances DMSO-induced cardiomyogenic differentiation of P19 cells

Alpha-lipoic acid (α-LA) is a potent antioxidant that acts as an essential cofactor in mitochondrial dehydrogenase reactions. α-LA has been shown to possess anti-inflammatory and cytoprotective properties, and is used to improve symptoms of diabetic neuropathy. However, the role of α-LA in stem cell differentiation and the underlying molecular mechanisms remain unknown. In the present study, we showed that α-LA significantly promoted dimethyl sulfoxide (DMSO)-induced cardiomyogenic differentiation of mouse embryonic carcinoma P19 cells. α-LA dose dependently increased beating embryonic body (EB) percentages of DMSO-differentiated P19 cells. The expressions of cardiac specific genes TNNT2, Nkx2.5, GATA4, MEF2C, and MLC2V and cardiac isoform of troponin T (cTnT)-positively stained cell population were significantly up-regulated by the addition of α-LA. We also demonstrated that the differentiation time after EB formation was critical for α-LA to take effect. Interestingly, without DMSO treatment, α-LA did not stimulate the cardiomyogenic differentiation of P19 cells. Further investigation indicated that collagen synthesis-enhancing activity, instead of the antioxidative property, plays a significant role in the cardiomyogenic differentiation-promoting function of α-LA. These findings highlight the potential use of α-LA for regenerative therapies in heart diseases.

Effects of lithium on inflammation

Lithium is an effective medication for the treatment of bipolar affective disorder. Accumulating evidence suggests that inflammation plays a role in the pathogenesis of bipolar disorder and that lithium has anti-inflammatory effects that may contribute to its therapeutic efficacy. This article summarizes the studies which examined the effects of lithium on pro- and anti-inflammatory mediators. Some of the summarized data suggest that lithium exerts anti-inflammatory effects (e.g., suppression of cyclooxygenase-2 expression, inhibition of interleukin (IL)-1β and tumor necrosis factor-α production, and enhancement of IL-2 and IL-10 synthesis). Nevertheless, there is a large body of data which indicates that under certain experimental conditions lithium also exhibits pro-inflammatory properties (e.g., induction of IL-4, IL-6 and other pro-inflammatory cytokines synthesis). The reviewed studies utilized various experimental model systems, and it is thus difficult to draw an unequivocal conclusion regarding the effect of lithium on specific inflammatory mediators.

Alpha-lipoic acid effects on brain glial functions accompanying double-stranded RNA antiviral and inflammatory signaling

Double-stranded RNAs (dsRNA) serve as viral ligands that trigger innate immunity in astrocytes and microglial, as mediated through Toll-like receptor 3 (TLR3) and dsRNA-dependent protein kinase (PKR). Beneficial transient TLR3 and PKR anti-viral signaling can become deleterious when events devolve into inflammation and cytotoxicity. Viral products in the brain cause glial cell dysfunction, and are a putative etiologic factor in neuropsychiatric disorders, notably schizophrenia, bipolar disorder, Parkinson's, and autism spectrum. Alpha-lipoic acid (LA) has been proposed as a possible therapeutic neuroprotectant. The objective of this study was to test our hypothesis that LA can control untoward antiviral mechanisms associated with neural dysfunction. Utilizing rat brain glial cultures (91% astrocytes:9% microglia) treated with PKR- and TLR3-ligand/viral mimetic dsRNA, polyinosinic-polycytidylic acid (polyI:C), we report in vitro glial antiviral signaling and LA reduction of the effects of this signaling. LA blunted the dsRNA-stimulated expression of IFNα/β-inducible genes Mx1, PKR, and TLR3. And in polyI:C treated cells, LA promoted gene expression of rate-limiting steps that benefit healthy neural redox status in glutamateric systems. To this end, LA decreased dsRNA-induced inflammatory signaling by downregulating IL-1β, IL-6, TNFα, iNOS, and CAT2 transcripts. In the presence of polyI:C, LA prevented cultured glial cytotoxicity which was correlated with increased expression of factors known to cooperatively control glutamate/cystine/glutathione redox cycling, namely glutamate uptake transporter GLAST/EAAT1, γ-glutamyl cysteine ligase catalytic and regulatory subunits, and IL-10. Glutamate exporting transporter subunits 4F2hc and xCT were downregulated by LA in dsRNA-stimulated glia. l-Glutamate net uptake was inhibited by dsRNA, and this was relieved by LA. Glutathione synthetase mRNA levels were unchanged by dsRNA or LA. This study demonstrates the protective effects of LA in astroglial/microglial cultures, and suggests the potential for LA efficacy in virus-induced CNS pathologies, with the caveat that antiviral benefits are concomitantly blunted. It is concluded that LA averts key aspects of TLR3- and PKR-provoked glial dysfunction, and provides rationale for exploring LA in whole animal and human clinical studies to blunt or avert neuropsychiatric disorders.