Cinnamaldehyde inhibits psoriasis­like inflammation by suppressing proliferation and inflammatory response of keratinocytes via inhibition of NF­κB and JNK signaling pathways.

Psoriasis is a systemic immune­mediated inflammatory disease characterized by uncontrolled keratinocyte proliferation and poor differentiation. Cinnamaldehyde (CIN) has been shown to inhibit the proliferation and inflammatory response of primary and immortalized immune cells. However, to the best of our knowledge, the role of CIN in the progression of psoriasis remains unclear. Therefore, the present study aimed to investigate the biological role of CIN in psoriasis. To mimic abnormal proliferation and differentiation in keratinocytes in vitro, normal human epidermal keratinocytes (NHEKs) were stimulated with M5 (IL­1α, IL­17A, IL­22, oncostatin M and TNF­α). The viability and proliferation of NHEKs were analyzed using Cell Counting Kit­8 and 5­Ethynyl­2'­deoxyuridine assays, respectively. Western blotting was used to analyze the expression levels of keratin 1, filaggrin and loricrin in NHEKs. The results of the present study revealed that CIN significantly inhibited the proliferation and cell cycle progression, and promoted the differentiation of M5­stimulated NHEKs. CIN also markedly attenuated the extent of oxidative stress­induced damage in M5­stimulated NHEKs. Moreover, CIN ameliorated M5­induced inflammatory injury in NHEKs, as evidenced by the decreased levels of multiple inflammatory factors. Furthermore, CIN notably downregulated the expression levels of phosphorylated (p)­inhibitor of NF­κB, p­p65 and p­JNK in M5­stimulated NHEKs. In conclusion, the present data suggested that CIN may protect NHEKs against M5­induced hyperproliferation and inflammatory injury via inhibition of NF­κB and JNK signaling pathways. These results provide a novel insight on the role of CIN in psoriasis.

Acrolein: A Potential Mediator of Oxidative Damage in Diabetic Retinopathy.

Diabetic retinopathy (DR) is the leading cause of vision loss among working-age adults. Extensive evidences have documented that oxidative stress mediates a critical role in the pathogenesis of DR. Acrolein, a product of polyamines oxidation and lipid peroxidation, has been demonstrated to be involved in the pathogenesis of various human diseases. Acrolein's harmful effects are mediated through multiple mechanisms, including DNA damage, inflammation, ROS formation, protein adduction, membrane disruption, endoplasmic reticulum stress, and mitochondrial dysfunction. Recent investigations have reported the involvement of acrolein in the pathogenesis of DR. These studies have shown a detrimental effect of acrolein on the retinal neurovascular unit under diabetic conditions. The current review summarizes the existing literature on the sources of acrolein, the impact of acrolein in the generation of oxidative damage in the diabetic retina, and the mechanisms of acrolein action in the pathogenesis of DR. The possible therapeutic interventions such as the use of polyamine oxidase inhibitors, agents with antioxidant properties, and acrolein scavengers to reduce acrolein toxicity are also discussed.

A Synthetic Snake-Venom-Based Tripeptide Protects PC12 Cells from the Neurotoxicity of Acrolein by Improving Axonal Plasticity and Bioenergetics.

The synthetic peptide p-BTX-I is based on the native peptide (formed by glutamic acid, valine and tryptophan) isolated from Bothrops atrox venom. We have previously demonstrated its neuroprotective and neurotrophic properties in PC12 cells treated with the dopaminergic neurotoxin 1-methyl-4-phenylpyridinium (MPP+). Now, we have investigated the neuroprotective effects and mechanisms of p-BTX-I against the toxicity of acrolein in PC12 cells. Studies have demonstrated that acrolein might play an important role in the etiology of Alzheimer's disease (AD), which is characterized by neuronal and synaptic loss. Our results showed that not only acrolein reduced cell differentiation and cell viability, but also altered the expression of markers of synaptic communication (synapsin I), energy metabolism (AMPK-α, Sirt I and glucose uptake), and cytoskeleton (ß-III-tubulin). Treatment with p-BTX-I increased the percentage of differentiation in cells treated with acrolein and significantly attenuated cell viability loss, besides counteracting the negative effects of acrolein on synapsin I, AMPK-α, Sirt I, glucose uptake, and ß-III-tubulin. Additionally, p-BTX-I alone increased the expression of apolipoprotein E (apoE) gene, associated with the proteolytic degradation of ß-amyloid peptide aggregates, a hallmark of AD. Taken together, these findings demonstrate that p-BTX-I protects against acrolein-induced neurotoxicity and might be a tool for the development of novel drugs for the treatment of neurodegenerative diseases.

The potential role of acrolein in plant ferroptosis-like cell death.

The iron dependent, programmed cell death, ferroptosis was described first in tumour cells. It showed distinct features from the already known cell death forms such as apoptosis, necrosis and autophagy. The caspase independent cell death could be induced by the depletion of glutathione by erastin or by the inhibition of the lipid peroxide scavenger enzyme GPX4 by RSL3 and it was accompanied by the generation of lipid reactive oxygen species. Recently, ferroptosis-like cell death associated to glutathione depletion, lipid peroxidation and iron dependency could also be induced in plant cells by heat treatment. Unfortunately, the mediators and elements of the ferroptotic pathway have not been described yet. Our present results on Arabidopsis thaliana cell cultures suggest that acrolein, a lipid peroxide-derived reactive carbonyl species, is involved in plant ferroptosis-like cell death. The acrolein induced cell death could be mitigated by the known ferroptosis inhibitors such as Ferrostatin-1, Deferoxamine, α-Tocopherol, and glutathione. At the same time acrolein can be a mediator of ferroptosis-like cell death in plant cells since the known ferroptosis inducer RSL3 induced cell death could be mitigated by the acrolein scavenger carnosine. Finally, on the contrary to the caspase independent ferroptosis in human cells, we found that caspase-like activity can be involved in plant ferroptosis-like cell death.

Modification of endothelial nitric oxide synthase by 4-oxo-2(E)-nonenal(ONE) in preeclamptic placentas.

Preeclampsia (PE) is a leading cause of pregnancy complications, affecting 3-7% of pregnant women worldwide. The pathophysiology of preeclampsia involves a redox imbalance, oxidative stress and a reduced nitric oxide (NO) bioavailability. The molecular and cellular mechanisms leading to the dysfunction of the placental endothelial NO synthase (eNOS) are not clarified. This study was designed to investigate whether aldehydes generated by lipid peroxidation products (LPP), may contribute to placental eNOS dysfunction in PE. The analysis of placentas from PE-affected patients and normal pregnancies, showed a significant increase in protein carbonyl content, indicative of oxidative stress-induced protein modification, as shown by the accumulation of acrolein, 4-hydroxynonenal (HNE), and 4-oxo-2(E)-nonenal (ONE) adducts in PE placentas. In contrast, the levels of these LPP-adducts were low in placentas from normal pregnancies. Immunofluorescence and confocal experiments pointed out a colocalization of eNOS with ONE-Lys adducts, whereas eNOS was not modified in normal placentas. LC-MS/MS analysis of recombinant eNOS preincubated with ONE, allowed to identify several ONE-modified Lys-containing peptides, confirming that eNOS may undergo post-translational modification by LPP. The preincubation of HTR-8/SVneo human trophoblasts (HTR8) with ONE, resulted in ONE-Lys modification of eNOS and a reduced generation of NO. ONE inhibited the migration of HTR8 trophoblasts in the wound closure model, and this was partly restored by the NO donor, NOC-18, which confirmed the important role of NO in the invasive potential of trophoblasts. In conclusion, placental eNOS is modified by ONE in PE placentas, which emphasizes the sensitivity of this protein to oxidative stress in the disturbed redox environment of preeclamptic pregnancies.

Protective effects of curcumin on acrolein-induced neurotoxicity in HT22 mouse hippocampal cells.

BACKGROUND: Aging is one of the most important inevitable risk factors of Alzheimer disease (AD). Oxidative stress plays a critical role in the process of aging. Curcumin has been proposed to improve neural damage, especially neurodegenerative injury, through its antioxidant and anti-inflammatory properties. Therefore, we investigated the effects of curcumin on acrolein-induced AD-like pathologies in HT22 cells. METHODS: HT22 murine hippocampal neuronal cells were treated with 25µM acrolein for 24h with or without pre-treating with curcumin at the selected optimum concentration (5µg/mL) for 30min. Cell viability and apoptosis were measured by CCK8 assay and flow cytometric analysis. Levels of glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA) were detected by a GSH assay kit or commercial assay kits, respectively. Alterations in the expression of BDNF/TrkB and key enzymes involved in amyloid precursor protein (APP) metabolism were assessed by western blotting. RESULTS: Data showed that curcumin significantly reversed acrolein-induced oxidative stress indicated by depletion of GSH and SOD, and elevation of MDA. The findings also suggested curcumin's potential in protecting HT22 cells against acrolein through regulating the BDNF/TrkB signaling. In addition, acrolein-induced reduction in A-disintegrin and metalloprotease, and the increase of amyloid precursor protein, ß-secretase, and receptor for advanced glycation end products were reversed either, and most of them were nearly restored to the control levels by curcumin. CONCLUSION: These findings demonstrate the protective effects of curcumin on acrolein-induced neurotoxicity in vitro, which further suggests its potential role in the treatment of AD.

Cow's milk neutralizes the cytotoxicity of acrolein, a putative carcinogen in cigarette smoke.

Cigarette smoke is a strong and independent risk factor for esophageal cancer, while the consumption of cow's milk has been proposed as a protective factor. The mechanistic role of milk in preventing cancer, however, has not been clarified. We focused our study on acrolein, an abundant unsaturated aldehyde present in cigarette smoke. Acrolein is a highly toxic compound and a putative carcinogen. Using a cell culture system, we found that (1) acrolein caused necrosis in Ramos Burkitt's lymphoma cells, (2) the necrosis was inhibited by preincubation of acrolein with milk, and (3) acrolein formed adducts with milk proteins. These results indicated the protective effects of cow's milk against acrolein-induced cytotoxicity via protein-acrolein adduct formation.

Acrolein toxicity at advanced age: present and future.

It is thought that tissue damage at advanced age is mainly caused by ROS (reactive oxygen species, O2-, H2O2, and ·OH). However, it was found that acrolein (CH2=CH-CHO) is more toxic than ROS, and is mainly produced from spermine (SPM), one of the polyamines, rather than from unsaturated fatty acids. Significant amounts of SPM are present normally as SPM-ribosome complexes, and contribute to protein synthesis. However, SPM was released from ribosomes due to the degradation of ribosomal RNA by ·OH or the binding of Ca2+ to ribosomes, and acrolein was produced from free SPM by polyamine oxidases, particularly by SPM oxidase. Acrolein inactivated several proteins such as GAPDH (glycelaldehyde-3-phosphate dehydrogenase), and also stimulated MMP-9 (matrix metalloproteinase-9) activity. Acrolein-conjugated GAPDH translocated to nucleus, and caused apoptosis like nitrosylated GAPDH. Through acrolein conjugation with several proteins, acrolein causes tissue damage during brain stroke, dementia, renal failure, and primary Sjögren's syndrome. Thus, development of acrolein scavengers with less side effects is very important to maintain QOL (quality of life) of elderly people.

Multitarget trehalose-carnosine conjugates inhibit Aß aggregation, tune copper(II) activity and decrease acrolein toxicity.

Increasing evidence is accumulating, showing that neurodegenerative disorders are somehow associated with the toxicity of amyloid aggregates, metal ion dyshomeostasis as well as with products generated by oxidative stress. Within the biological oxidation products, acrolein does have a prominent role. A promising strategy to deal with the above neurogenerative disorders is to use multi-functions bio-molecules. Herein, we show how a class of bio-conjugates takes advantage of the antiaggregating, antioxidant and antiglycating properties of trehalose and carnosine. Their ability to sequester acrolein and to inhibit both self- and metal-induced aggregation is here reported. The copper(II) coordination properties of a new trehalose-carnosine conjugate and the relative antioxidant effects have also been investigated.

Synthesis of Reactive Polymers for Acrolein Capture Using AGET ATRP.

Acrolein is a toxic metabolite of the anticancer agent cyclophosphamide (CP). Current strategies to mitigate acrolein toxicity are insufficient, and in this brief article, we report the synthesis of well-defined low molecular weight block copolymers using activators generated by electron transfer atom transfer radical polymerization (AGET ATRP) capable of reacting with the cytotoxic small molecule acrolein. Acrolein reactivity was introduced into the block copolymers via incorporation of either (a) aminooxy or (b) sulfhydryl groups. The cytoprotective effect of the polymers was compared to sodium 2-sulfanylethanesulfonate (mesna) the current gold standard for protection from CP urotoxicity, and we found that the polymers bearing sulfhydryl moieties demonstrated superior cytoprotective activity.

Lithium prevents acrolein-induced neurotoxicity in HT22 mouse hippocampal cells.

Acrolein is a highly electrophilic alpha, beta-unsaturated aldehyde to which humans are exposed in many situations and has been implicated in neurodegenerative diseases, such as Alzheimer's disease. Lithium is demonstrated to have neuroprotective and neurotrophic effects in brain ischemia, trauma, neurodegenerative disorders, and psychiatric disorders. Previously we have found that acrolein induced neuronal death in HT22 mouse hippocampal cells. In this study, the effects of lithium on the acrolein-induced neurotoxicity in HT22 cells as well as its mechanism(s) were investigated. We found that lithium protected HT22 cells against acrolein-induced damage by the attenuation of reactive oxygen species and the enhancement of the glutathione level. Lithium also attenuated the mitochondrial dysfunction caused by acrolein. Furthermore, lithium significantly increased the level of phospho-glycogen synthase kinase-3 beta (GSK-3ß), the non-activated GSK-3ß. Taken together, our findings suggest that lithium is a protective agent for acrolein-related neurotoxicity.

Rapamycin inhibits acrolein-induced apoptosis by alleviating ROS-driven mitochondrial dysfunction in male germ cells.

OBJECTIVES: Acrolein (Acr) is a highly reactive α, ß-unsaturated aldehyde, which can induce reactive oxygen species (ROS) generation. Several factors, including lipid peroxidation, clinical use of cyclophosphamide, fried foods, automobile exhausts, smoking and aging can increase its concentration in blood serum. Mounting evidence has suggested that Acr-induced ROS might reduce quality of sperm. Thus, the aim of this study was to examine reproductive toxicity of Acr-caused ROS in vitro and find a means to alleviate it. MATERIALS AND METHODS: We investigated the effects of Acr on male germ cell (MGC)-derived GC-1 cells in vitro. Dihydroethidium and DCFH-DA fluorescent dyes were used to determine generation of intracellular ROS. RESULTS: We found that Acr induced ROS generation, which was accompanied by reduced Bcl2/Bax ratio, substantial decline in mitochondrial membrane potential, and further promoted apoptosis of MGCs. Furthermore, Rapamycin was capable of alleviating Acr-induced ROS, reducing ROS-induced apoptosis by increasing ratio of Bcl2/Bax mRNA and proteins, and protecting MGC mitochondrial membranes. CONCLUSION: Rapamycin inhibited Acr-induced apoptosis by alleviating ROS-driven mitochondrial dysfunction in MGCs.

Curcumin analog 1, 5-bis (2-trifluoromethylphenyl)-1, 4-pentadien-3-one exhibits enhanced ability on Nrf2 activation and protection against acrolein-induced ARPE-19 cell toxicity.

Curcumin, a phytochemical agent in the spice turmeric, has received increasing attention for its anticancer, anti-inflammatory and antioxidant properties. However, application of curcumin has been limited due to its insolubility in water and poor bioavailability both clinically and experimentally. In addition, the protective effects and mechanisms of curcumin in eye diseases have been poorly studied. In the present study, we synthesized a curcumin analog, 1, 5-bis (2-trifluoromethylphenyl)-1, 4-pentadien-3-one (C3), which displayed improved protective effect against acrolein-induced toxicity in a human retinal pigment epithelial cell line (ARPE-19). At 5 µM, curcumin completely protected against acrolein-induced cell oxidative damage and preserved GSH levels and mitochondrial function. Surprisingly, C3 displayed a complete protective effect at 0.5 µM, which was much more efficient than curcumin. Both 0.5 µM C3 and 5 µM curcumin induced Nrf2 nuclear translocation and Nrf2 target genes transcription similarly. Experiments using Nrf2 siRNA showed that the protective effects of curcumin and C3 were eliminated by Nrf2 knockdown. Additionally, both curcumin and C3 activated the PI3/Akt pathway, however, Nrf2 activation was independent of this pathway, and therefore, we hypothesized that both curcumin and C3 activated phase II enzymes via directly disrupting the Nrf2/Keap1 complex and promoting Nrf2's nuclear translocation. Since acrolein challenge of ARPE-19 cells has been used as a model of smoking and age-related macular degeneration (AMD), we concluded that the curcumin analog, C3, may be a more promising drug candidate for its potential application for the prevention and treatment of eye diseases, such as AMD.

Spinal transient receptor potential ankyrin 1 channel induces mechanical hypersensitivity, increases cutaneous blood flow, and mediates the pronociceptive action of dynorphin A.

We characterized pain behavior and cutaneous blood flow response induced by activation of the spinal transient receptor potential ankyrin 1 (TRPA1) channel using intrathecal drug administrations in the rat. Additionally, we assessed whether the pronociceptive actions induced by intrathecally administered dynorphin A, cholecystokinin or prostaglandin F(2α) are mediated by the spinal TRPA1 channel. Cinnamaldehyde, a TRPA1 agonist, produced a dose-related (3-10 µg) cutaneous blood flow increase and mechanical hypersensitivity effect. These effects at the currently used doses were of short duration and attenuated, although not completely, by pretreatment with A-967079, a TRPA1 antagonist. The cinnamaldehyde-induced hypersensitivity was also reduced by pretreatment with minocycline (an inhibitor of microglial activation), but not by carbenoxolone (a gap junction decoupler). In vitro study, however, indicated that minocycline only poorly blocks the TRPA1 channel. The mechanical hypersensitivity effect induced by dynorphin A, but not that by cholecystokinin or prostaglandin F(2α), was attenuated by a TRPA1 antagonist Chembridge-5861528 as well as A-967079. The cinnamaldehyde-induced cutaneous blood flow increase was not suppressed by MK-801, an NMDA receptor antagonist, or bicuculline, a GABA(A) receptor antagonist. The results indicate that spinal TRPA1 channels promote mechanical pain hypersensitivity and due to antidromic activation of nociceptive nerve fibers increase cutaneous blood flow. The attenuation of the cinnamaldehyde-induced hypersensitivity effect by minocycline may be explained by action other than block of the TRPA1 channel. Moreover, the spinal TRPA1 channel is involved in mediating the pronociceptive action of dynorphin A, but not that of the spinal cholecystokinin or prostaglandin F(2α).

Acrolein cytotoxicity in hepatocytes involves endoplasmic reticulum stress, mitochondrial dysfunction and oxidative stress.

Acrolein is a common environmental, food and water pollutant and a major component of cigarette smoke. Also, it is produced endogenously via lipid peroxidation and cellular metabolism of certain amino acids and drugs. Acrolein is cytotoxic to many cell types including hepatocytes; however the mechanisms are not fully understood. We examined the molecular mechanisms underlying acrolein hepatotoxicity in primary human hepatocytes and hepatoma cells. Acrolein, at pathophysiological concentrations, caused a dose-dependent loss of viability of hepatocytes. The death was apoptotic at moderate and necrotic at high concentrations of acrolein. Acrolein exposure rapidly and dramatically decreased intracellular glutathione and overall antioxidant capacity, and activated the stress-signaling MAP-kinases JNK, p42/44 and p38. Our data demonstrate for the first time in human hepatocytes, that acrolein triggered endoplasmic reticulum (ER) stress and activated eIF2α, ATF-3 and -4, and Gadd153/CHOP, resulting in cell death. Notably, the protective/adaptive component of ER stress was not activated, and acrolein failed to up-regulate the protective ER-chaperones, GRP78 and GRP94. Additionally, exposure to acrolein disrupted mitochondrial integrity/function, and led to the release of pro-apoptotic proteins and ATP depletion. Acrolein-induced cell death was attenuated by N-acetyl cysteine, phenyl-butyric acid, and caspase and JNK inhibitors. Our data demonstrate that exposure to acrolein induces a variety of stress responses in hepatocytes, including GSH depletion, oxidative stress, mitochondrial dysfunction and ER stress (without ER-protective responses) which together contribute to acrolein toxicity. Our study defines basic mechanisms underlying liver injury caused by reactive aldehyde pollutants such as acrolein.

Augmented glutathione synthesis decreases acrolein toxicity.

We have shown recently that acrolein is more strongly involved in cell damage than reactive oxygen species during brain infarction. Thus, we tried to isolate cells with reduced susceptibility to acrolein toxicity to clarify how acrolein is detoxified under cell culture conditions. The IC(50) of acrolein in mouse mammary carcinoma FM3A cells and in neuroblastoma Neuro2a cells was 2.6 and 4.2µM, respectively, but in acrolein toxicity-decreasing FM3A (FM3A-ATD) cells and Neuro2a (Neuro2a-ATD) cells, it was 7.6 and 8.4µM, respectively. In both FM3A-ATD and Neuro2a-ATD cells, the concentration of glutathione (GSH) was increased, so that detoxification occurred through acrolein conjugation with GSH. In FM3A-ATD cells, the level of a rate-limiting enzyme of GSH synthesis, γ-glutamylcysteine ligase catalytic unit (GCLC), was increased through the reactivation of one inactive allele of GCLC genes in FM3A cells. In Neuro2a-ATD cells, phosphorylation of transcription factors (c-Jun and NF-κB) necessary for expression of genes for GCLC and glutathione synthetase (GSHS) involved in GSH synthesis was stimulated, so that transcription of two genes increased in Neuro2a-ATD cells. Phosphorylation of JNK (c-Jun N-terminal kinase), which catalyzes phosphorylation of c-Jun and NF-κB p65, was also increased in Neuro2a-ATD cells, suggesting that activation of JNK kinase is responsible for the increase in GSH. These results support the idea that GSH plays important roles in detoxification of acrolein, because GSH is increased in both FM3A-ATD and Neuro2a-ATD cells.

Menthol attenuates respiratory irritation responses to multiple cigarette smoke irritants.

Menthol, the cooling agent in peppermint, is added to almost all commercially available cigarettes. Menthol stimulates olfactory sensations, and interacts with transient receptor potential melastatin 8 (TRPM8) ion channels in cold-sensitive sensory neurons, and transient receptor potential ankyrin 1 (TRPA1), an irritant-sensing channel. It is highly controversial whether menthol in cigarette smoke exerts pharmacological actions affecting smoking behavior. Using plethysmography, we investigated the effects of menthol on the respiratory sensory irritation response in mice elicited by smoke irritants (acrolein, acetic acid, and cyclohexanone). Menthol, at a concentration (16 ppm) lower than in smoke of mentholated cigarettes, immediately abolished the irritation response to acrolein, an agonist of TRPA1, as did eucalyptol (460 ppm), another TRPM8 agonist. Menthol's effects were reversed by a TRPM8 antagonist, AMTB. Menthol's effects were not specific to acrolein, as menthol also attenuated irritation responses to acetic acid, and cyclohexanone, an agonist of the capsaicin receptor, TRPV1. Menthol was efficiently absorbed in the respiratory tract, reaching local concentrations sufficient for activation of sensory TRP channels. These experiments demonstrate that menthol and eucalyptol, through activation of TRPM8, act as potent counterirritants against a broad spectrum of smoke constituents. Through suppression of respiratory irritation, menthol may facilitate smoke inhalation and promote nicotine addiction and smoking-related morbidities.

Inhibition of acrolein-stimulated MUC5AC expression by Platycodon grandiflorum root-derived saponin in A549 cells.

Mucin overproduction is a hallmark of chronic airway diseases such as chronic obstructive pulmonary disease. In this study, we investigated the inhibition of acrolein-induced expression of mucin 5, subtypes A and C (MUC5AC) by Changkil saponin (CKS) in A549 cells. Acrolein, a known toxin in tobacco smoke and an endogenous mediator of oxidative stress, increases the expression of airway MUC5AC, a major component of airway mucus. CKS, a Platycodon grandiflorum root-derived saponin, inhibited acrolein-induced MUC5AC expression and activity, through the suppression of NF-κB activation. CKS also repressed acrolein-induced phosphorylation of ERK1/2, JNK1/2, and p38MAPK, which are upstream signaling molecules that control MUC5AC expression. In addition, the MAPK inhibitors PD98059 (ERK1/2), SP600125 (JNK1/2), and SB203580 (p38 MAPK), and a PKC delta inhibitor (rottlerin; PKCδ) inhibited acrolein-induced MUC5AC expression and activity. CKS repressed acrolein-induced phosphorylation of PKCδ. Moreover, a reactive oxygen species (ROS) inhibitor, N-acetylcysteine, inhibited acrolein-induced MUC5AC expression and activity through the suppression of PKCδ and MAPK activation, and CKS repressed acrolein-induced ROS production. These results suggest that CKS suppresses acrolein-induced MUC5AC expression by inhibiting the activation of NF-κB via ROS-PKCδ-MAPK signaling.

NBHA reduces acrolein-induced changes in ARPE-19 cells: possible involvement of TGFß.

PURPOSE: Acrolein, a toxic, reactive aldehyde formed metabolically and environmentally, has been implicated in the damage to and dysfunction of the retinal pigment epithelium (RPE) that accompanies age-related macular degeneration (AMD). Our purpose was to investigate the potential of acrolein to influence the release of transforming growth factor beta-2 (TGFß2) and vascular endothelial growth factor (VEGF), to assess the ability of N-benzylhydroxylamine (NBHA) to prevent the effect of acrolein on cytokine release and reduction of viable cells, and to explore the pathway by which acrolein might be causing the increase of VEGF. MATERIALS AND METHODS: Confluent ARPE-19 cells were treated with acrolein and/or NBHA. They were also pretreated with SIS3, a specific inhibitor of SMAD 3, and ZM39923, a JAK3 inhibitor, before being treated with acrolein. Viable cells were counted; ELISA was used to measure the TGFß2 and/or VEGF in the conditioned media. RESULTS: Acrolein was shown to reduce the number of viable ARPE-19 cells and to upregulate the release of the proangiogenic cytokines TGFß2 and VEGF. Co-treatment with 200 µM NBHA significantly reduced the effects of acrolein on viable cell number and TGFß2 release. Pretreatment of the cells with SIS3 partially blocked the action of acrolein on decreased viable cell number and VEGF upregulation, suggesting that part of the effects of acrolein are mediated by the increased levels of TGFß and its signaling. CONCLUSIONS: Our results suggest that the action of acrolein on the reduction of viability and VEGF increase by ARPE-19 cells is partially mediated by TGFß2. By reducing the effects of acrolein, NBHA and SIS3 could be potential pharmacological agents in the prevention and progression of acrolein-induced damage to the RPE that relates to AMD.