N-acetylcysteine Provides Cytoprotection in Murine Oligodendrocytes through Heme Oxygenase-1 Activity

In vitro immunotoxicity effects of carbendazim were inhibited by n-acetylcysteine in microglial BV-2 cells

Carbendazim (CBZ) is a benzimidazole fungicide widely used worldwide in industrial, agricultural, and veterinary practices. Although, CBZ was found in all brain tissues causing serious neurotoxicity, its impact on brain immune cells remain scarcely understood. Our study investigated the in vitro effects of CBZ on activated microglial BV-2 cells. Lipopolysaccharide (LPS)-stimulated BV-2 cells were exposed to increasing concentrations of CBZ and cytokine release was measured by ELISA, and Cytometric Bead Array (CBA) assays. Mitochondrial superoxide anion (O2·-) generation was evaluated by Dihydroethidium (DHE) and nitric oxide (NO) was assessed by Griess reagent. Lipid peroxidation was evaluated by measuring the malonaldehyde (MDA) levels. The transmembrane mitochondrial potential (ΔΨm) was detected by cytometry analysis with dihexyloxacarbocyanine iodide (DiOC6(3)) assay. CBZ concentration-dependently increased IL-1β, IL-6, TNF-α and MCP-1 by LPS-activated BV-2 cells. CBZ significantly promoted oxidative stress by increasing NO, O2·- generation, and MDA levels. In contrast, CBZ significantly decreased ΔΨm. Pre-treatment of BV-2 cells with N-acetylcysteine (NAC) reversed all the above mentioned immunotoxic parameters, suggesting a potential protective role of NAC against CBZ-induced immunotoxicity via its antioxidant and anti-inflammatory effects on activated BV-2 cells. Therefore, microglial proinflammatory over-activation by CBZ may be a potential mechanism by which CBZ could induce neurotoxicity and neurodegenerative disorders.

A Review of the Potential of Nuclear Factor [Erythroid-Derived 2]-like 2 Activation in Autoimmune Diseases

An autoimmune disease is the consequence of the immune system attacking healthy cells, tissues, and organs by mistake instead of protecting them. Inflammation and oxidative stress (OS) are well-recognized processes occurring in association with acute or chronic impairment of cell homeostasis. The transcription factor Nrf2 (nuclear factor [erythroid-derived 2]-like 2) is of major importance as the defense instrument against OS and alters anti-inflammatory activities related to different pathological states. Researchers have described Nrf2 as a significant regulator of innate immunity. Growing indications suggest that the Nrf2 signaling pathway is deregulated in numerous diseases, including autoimmune disorders. The advantageous outcome of the pharmacological activation of Nrf2 is an essential part of Nrf2-based chemoprevention and intervention in other chronic illnesses, such as neurodegeneration, cardiovascular disease, autoimmune diseases, and chronic kidney and liver disease. Nevertheless, a growing number of investigations have indicated that Nrf2 is already elevated in specific cancer and disease steps, suggesting that the pharmacological agents developed to mitigate the potentially destructive or transformative results associated with the protracted activation of Nrf2 should also be evaluated. The activators of Nrf2 have revealed an improvement in the progress of OS-associated diseases, resulting in immunoregulatory and anti-inflammatory activities; by contrast, the depletion of Nrf2 worsens disease progression. These data strengthen the growing attention to the biological properties of Nrf2 and its possible healing power on diseases. The evidence supporting a correlation between Nrf2 signaling and the most common autoimmune diseases is reviewed here. We focus on the aspects related to the possible effect of Nrf2 activation in ameliorating pathologic conditions based on the role of this regulator of antioxidant genes in the control of inflammation and OS, which are processes related to the progression of autoimmune diseases. Finally, the possibility of Nrf2 activation as a new drug development strategy to target pathogenesis is proposed.

Mechanistic insights into the biological activity of S-Sulfocysteine in CHO cells using a multi-omics approach

S-Sulfocysteine (SSC), a bioavailable L-cysteine derivative (Cys), is known to be taken up and metabolized in Chinese hamster ovary (CHO) cells used to produce novel therapeutic biological entities. To gain a deeper mechanistic insight into the SSC biological activity and metabolization, a multi-omics study was performed on industrially relevant CHO-K1 GS cells throughout a fed-batch process, including metabolomic and proteomic profiling combined with multivariate data and pathway analyses. Multi-layered data and enzymatical assays revealed an intracellular SSC/glutathione mixed disulfide formation and glutaredoxin-mediated reduction, releasing Cys and sulfur species. Increased Cys availability was directed towards glutathione and taurine synthesis, while other Cys catabolic pathways were likewise affected, indicating that cells strive to maintain Cys homeostasis and cellular functions.

Influence of dose and exposition time in the effectiveness of N-Acetyl-l-cysteine treatment in A549 human epithelial cells

N-Acetyl-l-cysteine (NAC) acts as a precursor of the tripeptide glutathione (GSH), one of the principal cell mechanisms for reactive oxygen species (ROS) detoxification. Chronic obstructive pulmonary disease (COPD) is associated with enhanced inflammatory response and oxidative stress and NAC has been used to suppress various pathogenic processes in this disease. Studies show that the effects of NAC are dose-dependent, and it appears that the efficient doses in vitro are usually higher than the achieved in vivo plasma concentrations. However, to date, the inconsistencies between the in vitro NAC antioxidant and anti-inflammatory in vitro effects, by reproducing the in vivo NAC plasma concentrations as well as high NAC concentrations. To do so, A549 were transfected with polyinosinic-polycytidylic acid (Poly (I:C)) and treated with NAC at different treatment periods. Oxidative stress, release of proinflammatory mediators and NFkB activation were analyzed. Results suggest that NAC at low doses in chronic administration has sustained antioxidant and anti-inflammatory effects, while acute treatment with high dose NAC exerts a strong antioxidant and anti-inflammatory response.

N-Acetylcysteine Reverses the Mitochondrial Dysfunction Induced by Very Long-Chain Fatty Acids in Murine Oligodendrocyte Model of Adrenoleukodystrophy

The accumulation of saturated very long-chain fatty acids (VLCFA, ≥C22:0) due to peroxisomal impairment leads to oxidative stress and neurodegeneration in X-linked adrenoleukodystrophy (ALD). Among the neural supporting cells, myelin-producing oligodendrocytes are the most sensitive to the detrimental effect of VLCFA. Here, we characterized the mitochondrial dysfunction and cell death induced by VLFCA, and examined whether N-acetylcysteine (NAC), an antioxidant, prevents the cytotoxicity. We exposed murine oligodendrocytes (158 N) to hexacosanoic acid (C26:0, 1-100 µM) for 24 h and measured reactive oxygen species (ROS) and cell death. Low concentrations of C26:0 (≤25 µM) induced a mild effect on cell survival with no alterations in ROS or total glutathione (GSH) concentrations. However, analysis of the mitochondrial status of cells treated with C26:0 (25 µM) revealed depletion in mitochondrial GSH (mtGSH) and a decrease in the inner membrane potential. These results indicate that VLCFA disturbs the mitochondrial membrane potential causing ROS accumulation, oxidative stress, and cell death. We further tested whether NAC (500 µM) can prevent the mitochondria-specific effects of VLCFA in C26:0-treated oligodendrocytes. Our results demonstrate that NAC improves mtGSH levels and mitochondrial function in oligodendrocytes, indicating that it has potential use in the treatment of ALD and related disorders.

Association between HO‑1 gene promoter polymorphisms and diseases (Review)

Heme oxygenase‑1 (HO‑1) is an inducible cytoprotective enzyme that degrades heme into free iron, carbon monoxide and biliverdin, which is then rapidly converted into bilirubin. These degradation products serve an important role in the regulation of inflammation, oxidative stress and apoptosis. While the expression level of HO‑1 is typically low in most cells, it may be highly expressed when induced by a variety of stimulating factors, a process that contributes to the regulation of cell homeostasis. In the 5'‑non‑coding region of the HO‑1 gene, there are two polymorphic sites, namely the (GT)n dinucleotide and T(‑413)A single nucleotide polymorphism sites, which regulate the transcriptional activity of HO‑1. These polymorphisms have been shown to be closely associated with the occurrence and progression of numerous diseases, including cardiovascular, pulmonary, liver and kidney, various types of cancer and viral diseases. The present article reviews the progress that has been made in research on the association between the two types of polymorphisms and these diseases, which is expected to provide novel strategies for the diagnosis, treatment and prognosis of various diseases.

From regenerative strategies to pharmacological approaches: can we fine-tune treatment for Parkinson's disease?

Parkinson's disease is the second most prevalent neurodegenerative disorder worldwide. Clinically, it is characterized by severe motor complications caused by progressive degeneration of dopaminergic neurons. Current treatment is focused on mitigating the symptoms through the administration of levodopa, rather than on preventing dopaminergic neuronal damage. Therefore, the use and development of neuroprotective/disease-modifying strategies is an absolute need that can lead to promising gains on translational research of Parkinson's disease. For instance, N-acetylcysteine, a natural compound with strong antioxidant effects, has been shown to modulate oxidative stress, preventing dopamine-induced cell death. Despite the evidence of neuroprotective and modulatory effects of this drug, as far as we know, it does not induce per se any regenerative process. Therefore, it would be of interest to combine the latter with innovative therapies that induce dopaminergic neurons repair or even differentiation, as stem cell-based strategies. Stem cells secretome has been proposed as a promising therapeutic approach for Parkinson's disease, given its ability to modulate cell viability/preservation of dopaminergic neurons. Such approach represents a shift in the paradigm, showing that cell-transplantation free therapies based on the use of stem cells secretome may represent a potential alternative for regenerative medicine of Parkinson's disease. Thus, in this review, we address the current understanding of the potential combination of stem cell free-based strategies and neuroprotective/disease-modifying strategies as a new paradigm for the treatment of central nervous system neurodegenerative diseases, like Parkinson's disease.

N,N'bis-(2-mercaptoethyl) isophthalamide (NBMI) exerts neuroprotection against lead-induced toxicity in U-87 MG cells

N,N'-bis(2-mercaptoethyl)isophthalamide (NBMI) is a novel lipophilic heavy metal chelator and thiol redox antioxidant. This study was designed to investigate the neuroprotective activity of NBMI in U-87 MG cells exposed to lead acetate (PbAc). Cells were pretreated with NBMI for 24 h prior to a 48 h exposure to PbAc. Cell death (55%, p < 0.0001) and reduction of intracellular GSH levels (0.70-fold, p < 0.005) induced by 250 µM Pb were successfully attenuated by NBMI pretreatment at concentrations as low as 10 µM. A similar pretreatment with the FDA-approved Pb chelator dimercaptosuccinic acid (DMSA) proved ineffective, indicating a superior PKPD profile for NBMI. Pretreatment with NBMI successfully counteracted Pb-induced neuroinflammation by reducing IL-1β (0.59-fold, p < 0.05) and GFAP expression levels. NBMI alone was also found to significantly increase ferroportin expression (1.97-fold, p < 0.05) thereby enhancing cellular ability to efflux heavy metals. While no response was observed on the apoptotic pathway, this study demonstrated for the first time that necrotic cell death induced by Pb in U-87 MG cells is successfully attenuated by NBMI. Collectively these data demonstrate NBMI to be a promising neuroprotective compound in the realm of Pb poisoning.

Pharmacological Targeting of Heme Oxygenase-1 in Osteoarthritis

Osteoarthritis (OA) is a common aging-associated disease that clinically manifests as joint pain, mobility limitations, and compromised quality of life. Today, OA treatment is limited to pain management and joint arthroplasty at the later stages of disease progression. OA pathogenesis is predominantly mediated by oxidative damage to joint cartilage extracellular matrix and local cells such as chondrocytes, osteoclasts, osteoblasts, and synovial fibroblasts. Under normal conditions, cells prevent the accumulation of reactive oxygen species (ROS) under oxidatively stressful conditions through their adaptive cytoprotective mechanisms. Heme oxygenase-1 (HO-1) is an iron-dependent cytoprotective enzyme that functions as the inducible form of HO. HO-1 and its metabolites carbon monoxide and biliverdin contribute towards the maintenance of redox homeostasis. HO-1 expression is primarily regulated at the transcriptional level through transcriptional factor nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2), specificity protein 1 (Sp1), transcriptional repressor BTB-and-CNC homology 1 (Bach1), and epigenetic regulation. Several studies report that HO-1 expression can be regulated using various antioxidative factors and chemical compounds, suggesting therapeutic implications in OA pathogenesis as well as in the wider context of joint disease. Here, we review the protective role of HO-1 in OA with a focus on the regulatory mechanisms that mediate HO-1 activity.

The Role of Natural Compounds and their Nanocarriers in the Treatment of CNS Inflammation

Neuroinflammation, which is involved in various inflammatory cascades in nervous tissues, can result in persistent and chronic apoptotic neuronal cell death and programmed cell death, triggering various degenerative disorders of the central nervous system (CNS). The neuroprotective effects of natural compounds against neuroinflammation are mainly mediated by their antioxidant, anti-inflammatory, and antiapoptotic properties that specifically promote or inhibit various molecular signal transduction pathways. However, natural compounds have several limitations, such as their pharmacokinetic properties and stability, which hinder their clinical development and use as medicines. This review discusses the molecular mechanisms of neuroinflammation and degenerative diseases of CNS. In addition, it emphasizes potential natural compounds and their promising nanocarriers for overcoming their limitations in the treatment of neuroinflammation. Moreover, recent promising CNS inflammation-targeted nanocarrier systems implementing lesion site-specific active targeting strategies for CNS inflammation are also discussed.