IPSE, a urogenital parasite-derived immunomodulatory protein, ameliorates ifosfamide-induced hemorrhagic cystitis through downregulation of pro-inflammatory pathways
Ifosfamide and other oxazaphosphorines can result in hemorrhagic cystitis, a constellation of complications caused by acrolein metabolites. We previously showed that a single dose of IPSE (Interleukin-4-inducing principle from Schistosoma eggs), a schistosome-derived host modulatory protein, can ameliorate ifosfamide-related cystitis; however, the mechanisms underlying this urotoxicity and its prevention are not fully understood. To provide insights into IPSE's protective mechanism, we undertook transcriptional profiling of bladders from ifosfamide-treated mice, with or without pretreatment with IPSE or IPSE-NLS (a mutant of IPSE lacking nuclear localization sequence). Ifosfamide treatment upregulated a range of proinflammatory genes. The IL-1β-TNFα-IL-6 proinflammatory cascade via NFκB and STAT3 pathways was identified as the key driver of inflammation. The NRF2-mediated oxidative stress response pathway, which regulates heme homoeostasis and expression of antioxidant enzymes, was highly activated. Anti-inflammatory cascades, namely Wnt, Hedgehog and PPAR pathways, were downregulated. IPSE drove significant downregulation of major proinflammatory pathways including the IL-1β-TNFα-IL-6 pathways, interferon signaling, and reduction in oxidative stress. IPSE-NLS reduced inflammation but not oxidative stress. Taken together, we have identified signatures of acute-phase inflammation and oxidative stress in ifosfamide-injured bladder, which are reversed by pretreatment with IPSE. This work revealed several pathways that could be therapeutically targeted to prevent ifosfamide-induced hemorrhagic cystitis.
Poricoic acid A enhances melatonin inhibition of AKI-to-CKD transition by regulating Gas6/AxlNFκB/Nrf2 axis
Renal ischemia-reperfusion injury (IRI) is a complex syndrome, which causes chronic kidney disease (CKD) after recovery from IRI-mediated acute kidney injury (AKI). There is no single therapy that could effectively prevent the renal injury after ischemia. In this study, the effects of melatonin or poricoic acid A (PAA) and their combination were investigated in protecting against AKI-to-CKD transition in rats and hypoxia/reoxygenation (H/R)-induced injury in cultured renal NRK-52E cells. Melatonin and PAA significantly reduced the magnitude of rise in serum creatinine and urea levels in IRI rats at days 3 and 14. Our results further showed that treatment with melatonin and PAA ameliorated renal fibrosis and podocyte injury by attenuating oxidative stress and inflammation via regulation of nuclear factor-kappa B (NF-κB) and nuclear factor-erythroid-2-related factor 2 (Nrf2) pathways in IRI rats. Melatonin and PAA protected against AKI-to-CKD transition by regulating growth arrest-specific 6 (Gas6)/AxlNFκB/Nrf2 signaling cascade. Melatonin and PAA initiallyupregulated Gas6/Axl signaling to reduce oxidative stress and inflammation in AKI and subsequently downregulated Gas6/Axl signaling to attenuate renal fibrosis and progression to CKD. Melatonin and PAA inhibited expression of extracellular matrix proteins. Poricoic acid A enhances melatonin-mediated inhibition of AKI-to-CKD transition by the regulating Gas6/AxlNFκB/Nrf2 signaling cascade. Notably, our study first identified Axl as a promising therapeutic target for prevention of AKI-to-CKD transition.
Helicobacter pylori infection promotes autophagy through Nrf2-mediated heme oxygenase upregulation in human gastric cancer cells
It has been reported that Helicobacter pylori (H. pylori) infection is one of the primary causes of gastritis and peptic ulcer diseases. More than 50% of the world's population is supposed to be infected by this bacterium. However, 90% of infected patients are asymptomatic, suggesting the existence of host defense mechanisms. Nrf2 is a transcription factors that plays a key role in cellular defence against oxidative stress and inflammation. Autophagy, an autodigestive process that degrades cellular organelles and proteins, plays an important role in maintaining cellular homeostasis. To investigate the molecular mechanisms responsible for cellular adaptive response to H. pylori induced gastric inflammation, human gastric epithelial cells and mice were infected with H. pylori. H. pylori infection induced expression of microtubule-associated light chain3 (LC3), an autophagic marker, through accumulation of reactive oxygen species and subsequently Nrf2 nuclear translocation in AGS cells. Furthermore, Nrf2-induced LC3 up-regulation was mediated by heme oxygenase-1 and its by-product, carbon monoxide. Taken together, Nrf2 may be considered to play a role in cellular adaptive response to H. pylori-induced gastritis by inducing autophagy.
A chalcone derivative suppresses the induction of TSLP in mice and human keratinocytes and attenuates OVA-induced antibody production in mice
Thymic stromal lymphopoietin (TSLP) is a key epithelial-derived factor that aggravates allergic diseases. Therefore, TSLP inhibitors are candidate compounds for the treatment of allergic diseases. Previously, we reported that KCMH-1, a mouse keratinocyte cell line, constitutively produces TSLP. In this study, we tried to identify inhibitors of TSLP by screening 2169 compounds in KCMH-1 cells and found one such chalcone derivative (code no. 16D10). 16D10 inhibited TSLP expression and TSLP promoter activation in HaCaT cells, a human keratinocyte cell line. Although nuclear factor kappa-B (NF-κB) is a key transcription factor for the induction of TSLP, 16D10 did not inhibit the activation pathway of NF-κB, such as degradation of inhibitor of κB (IκB) and p65 nuclear translocation. 16D10 activated the Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor (erythroid-derived 2)-like 2 (Nrf2) system, although this system was not involved in the inhibitory effect of 16D10. 16D10 also inhibited TSLP production in a lipopolysaccharide (LPS)- or ovalbumin (OVA)-induced air-pouch-type inflammation model. Further, repeated 16D10 administration diminished serum immunoglobulin G1 (IgG1) and IgE concentration in an OVA-induced air-pouch-type sensitization model. Taken together, these results indicate that 16D10 is an inhibitor of TSLP production and has an anti-allergic effect. This inhibitory effect is independent of the activation of NF-κB and the Keap1-Nrf2 system. Therefore, 16D10 could be a new type of candidate drug for allergic diseases.
High-Dose Paraquat Induces Human Bronchial 16HBE Cell Death and Aggravates Acute Lung Intoxication in Mice by Regulating Keap1/p65/Nrf2 Signal Pathway
Paraquat (PQ) intoxication seriously endangers human beings' health, however, the underlying mechanisms are still unclear. Here we found that PQ inhibits human bronchial 16HBE cell proliferation and promotes cell apoptosis, necrosis as well as ROS generation in a dose dependent manner. Of note, low-dose PQ (50 μM) induces cell autophagy, increases Nrf2 as well as p65 levels and has little impacts on Keap1, while high-dose PQ (500 μM) inhibits autophagy, upregulates Keap1 as well as downregulates p65 and Nrf2. In addition, we verified that p65 overexpression increases Nrf2 and its downstream targets in 16HBE cells, which are reversed by synergistically knocking down Nrf2. Our further results showed that high-dose PQ's effects on cell proliferation, apoptosis, ROS levels and autophagy are reversed by p65 overexpression. Besides, the protective effects of overexpressed p65 on high-dose PQ (500 μM) treated 16HBE cells are abrogated by synergistically knocking down Nrf2. In vivo experiments also showed that high-dose PQ promotes inflammatory cytokines secretion, lung fibrosis and cell apoptosis, inhibits cell proliferation in mice models by regulating Keap1/p65/Nrf2 signal pathway. Therefore, we concluded that high-dose PQ (500 μM) inhibits 16HBE cell proliferation and autophagy, promotes cell death and mice lung fibrosis by regulating Keap1/p65/Nrf2 signal pathway.
Lycopene attenuates aluminum-induced hippocampal lesions by inhibiting oxidative stress-mediated inflammation and apoptosis in the rat
Aluminum (Al) causes hippocampal lesions by oxidative stress, which is widely accepted as the primary pathogenesis of Al neurotoxicity. Lycopene (LYC), a naturally carotenoid, has received extensive attention due to its antioxidant effect. In this study, the neuroprotective effects and mechanisms of LYC against aluminum chloride (AlCl)-induced hippocampal lesions were explored. First, oral administration of LYC (4 mg/kg) alleviated AlCl-induced (150 mg/kg) cognition impairment and histopathological changes of the hippocampus in rats. Then, LYC significantly attenuated AlCl-induced oxidative stress, presenting as the reduced reactive oxygen species, malondialdehyde and 8-hydroxy-2'-deoxyguanosine levels, and increased glutathione level and superoxide dismutase activity. Moreover, LYC also protected the hippocampus from AlCl-induced apoptosis and neuroinflammation, as assessed by protein levels of p53, Bcl-2-associated X protein (Bax), B-cell lymphoma gene 2 (Bcl-2), Cytochrome c (Cyt c), cleaved caspase-3 and nuclear factor kappa B, as well as the mRNA levels of Bax, Bcl-2, tumor necrosis factor alpha, interleukin-6 and interleukin-1 beta. Finally, LYC increased nuclear factor-erythroid-2-related factor 2 (Nrf2) nuclear translocation and its downstream gene expression, including heme oxygenase-1, NAD(P)H: quinone oxidoreductase 1, glutamate cysteine ligase catalytic subunit and superoxide dismutase 1, which were involved in antioxidant, anti-apoptosis, and anti-inflammation. Overall, our findings demonstrate LYC attenuates Al-induced hippocampal lesions by inhibiting oxidative stress-mediated inflammation and apoptosis in the rat.
Genetic risk score combining six genetic variants associated with the cellular NRF2 expression levels correlates with Type 2 diabetes in the human population
Type 2 diabetes (T2D) is known as an inflammatory disease. NRF2 (Nuclear Factor Erythroid 2 Like2) encodes a transcription factor that binds to antioxidant response elements (AREs) and regulates the expression of genes involved in many antioxidant responses.
BML-111 accelerates the resolution of inflammation by modulating the Nrf2/HO-1 and NF-κB pathways in rats with ventilator-induced lung injury
The timely resolution of pulmonary inflammation coordinated by endogenous pro-resolving mediators helps limit lung tissue injury, but few endogenous pro-resolving mediators that are normally operative during acute inflammation. The protective effects of BML-111 (5(S)-6(R)-7-trihydroxyheptanoic acid methyl ester), a potent commercially available anti-inflammatory and pro-resolving mediator, on ventilation-induced lung injury (VILI) have been extensively studied, but its characteristics as a pro-resolving mediator have not. Here, anesthetized Sprague-Dawley rats were ventilated with a high tidal volume (20 mL/kg, HV) for 1 h and randomly allocated to recover for 6, 12, 24, 48, 72, 96 or 168 h; BML-111 was administered at the peak of inflammation to evaluate its pro-resolving effect on VILI. The one-hour HV induced a maximal pulmonary inflammatory response at 12 h that was largely resolved by 72 h. BML-111 largely resolved the maximal inflammatory response at 48 h; the resolution interval (Ri) was shortened by 26 h. Similarly, HV elicited a time course of changes in histopathology and pulmonary edema, and BML-111 alleviates these changes. Mechanistically, neutrophil apoptosis was significantly increased in BML-111-treated rats subjected to HV. The apoptosis inhibitor z-VAD-fmk partially reversed the proapoptotic actions of BML-111 on neutrophil and the resolving effects of BML-111 on VILI but had no effect alone. Importantly, the HV treatment activated the nuclear factor E2-related factor 2(Nrf2)/heme oxygenase-1(HO-1) and NF-κB signaling pathways in the lung tissue, and BML-111 further induced Nrf2 and HO-1 expression but inhibited the NF-κB pathway. Intriguingly, when we inhibited the Nrf2/HO-1 pathway with the HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX), Nrf2 expression was further increased, but the inhibitory effects of BML-111 on the NF-κB pathway and on the subsequent inflammatory response, and the proapoptotic actions on neutrophil were reversed. The results suggest that BML-111 promotes the resolution of HV-induced inflammation to mitigate VILI in rats, perhaps by modulating the Nrf2/HO-1 and NF-κB pathways and subsequently increasing neutrophil apoptosis.
PCB 126 induces monocyte/macrophage polarization and inflammation through AhR and NF-κB pathways
Polychlorinated biphenyls (PCBs) are persistent organic pollutants that contribute to inflammatory diseases such as atherosclerosis, and macrophages play a key role in the overall inflammatory response. Depending on specific environmental stimuli, macrophages can be polarized either to pro-inflammatory (e.g., M1) or anti-inflammatory (e.g., M2) phenotypes. We hypothesize that dioxin-like PCBs can contribute to macrophage polarization associated with inflammation. To test this hypothesis, human monocytes (THP-1) were differentiated to macrophages and subsequently exposed to PCB 126. Exposure to PCB 126, but not to PCB 153 or 118, significantly induced the expression of inflammatory cytokines, including TNFα and IL-1β, suggesting polarization to the pro-inflammatory M1 phenotype. Additionally, monocyte chemoattractant protein-1 (MCP-1) was increased in PCB 126-activated macrophages, suggesting induction of chemokines which regulate immune cell recruitment and infiltration of monocytes/macrophages into vascular tissues. In addition, oxidative stress sensitive markers including nuclear factor (erythroid-derived 2)-like 2 (NFE2L2; Nrf2) and down-stream genes, such as heme oxygenase 1 (HMOX1) and NAD(P)H quinone oxidoreductase 1 (NQO1), were induced following PCB 126 exposure. Since dioxin-like PCBs may elicit inflammatory cascades through multiple mechanisms, we then pretreated macrophages with both aryl hydrocarbon receptor (AhR) and NF-κB antagonists prior to PCB treatment. The NF-κB antagonist BMS-345541 significantly decreased mRNA and protein levels of multiple cytokines by approximately 50% compared to PCB treatment alone, but the AhR antagonist CH-223191 was protective to a lesser degree. Our data demonstrate the involvement of PCB 126 in macrophage polarization and inflammation, indicating another important role of dioxin-like PCBs in the pathology of atherosclerosis.
Mangiferin alleviates arsenic induced oxidative lung injury via upregulation of the Nrf2-HO1 axis
Arsenic contaminated drinking water consumption is a serious health issue around the world. Chronic inorganic arsenic exposure has been associated with respiratory dysfunctions. It exerts various detrimental effects, disrupting normal cellular homeostasis and turning on severe pulmonary complications. This study elucidated the role of mangiferin, a natural xanthone, against arsenic induced lung toxicity. Chronic exposure of sodium arsenite (NaAsO) at 10 mg/kg bw for 3 months abruptly increased the LDH release in broncho-alveolar lavage fluid, generated reactive oxygen species (ROS), impaired the antioxidant defense and distorted the alveoli architecture. It caused significant inflammatory outburst and promoted the apoptotic mode of cell death via upregulating the expressions of various proapoptotic molecules related to mitochondrial, extra-mitochondrial and ER stress mediated apoptotic pathway. Activation of inflammatory cascade led to disruption of alveolar capillary barrier and impaired Na/K-ATPase function that led to detaining of alveolar fluid clearance activity. Mangiferin due to its anti-inflammatory activity suppressed this inflammation and reduced inflammatory cell infiltration in lung tissue. It significantly restored the antioxidant balance and inhibited apoptosis in lung via upregulating Nrf2-HO1 axis.
Aloin reduces inflammatory gene iNOS via inhibition activity and p-STAT-1 and NF-κB
Aloin is the major anthraquinone glycoside obtained from the Aloe species and exhibits anti-inflammatory and anti-oxidative activities. Here, we aimed to determine the effects of aloin on heme oxygenase-1 (HO-1) induction and on the expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX) 2 in lipopolysaccharide (LPS)-activated human umbilical vein endothelial cells (HUVECs). To the end, aloin was tested whether aloin reduces iNOS protein expression and inflammatory markers (interleukin (IL)-1β and tumor necrosis factor (TNF)-α) in LPS-treated mice lung tissue. The results indicated that aloin affected HO-1 induction and reduced LPS-activated NF-κB-luciferase activity showed to preferential inhibition of iNOS/NO and COX-2/PGE2 that was partly related to inhibition of STAT-1 phosphorylation. In particular, aloin induced translocation of Nrf2 from cytosol into the nucleus by an increased Nrf2-ARE binding activity, and reduced IL-1β production in LPS-activated HUVECs. The reduced expression of iNOS/NO by aloin was reversed by siHO-1RNA-transfection. In LPS-treated mice, aloin significantly reduced iNOS protein in lung tissues, and TNF-α levels in the BALF. We concluded that aloin may be beneficial for treatment of lung injury.
CX3CR1-deficient microglia shows impaired signalling of the transcription factor NRF2: Implications in tauopathies
TAU protein aggregation is the main characteristic of neurodegenerative diseases known as tauopathies. Low-grade chronic inflammation is also another hallmark that indicates crosstalk between damaged neurons and glial cells. Previously, we have demonstrated that neurons overexpressing TAU release CX3CL1, which activates the transcription factor NRF2 signalling to limit over-activation in microglial cells in vitro and in vivo. However, the connection between CX3CL1/CX3CR1 and NRF2 system and its functional implications in microglia are poorly described. We evaluated CX3CR1/NRF2 axis in the context of tauopathies and its implication in neuroinflammation. Regarding the molecular mechanisms that connect CX3CL1/CX3CR1 and NRF2 systems, we observed that in primary microglia from Cx3cr1 mice the mRNA levels of Nrf2 and its related genes were significantly decreased, establishing a direct linking between both systems. To determine functional relevance of CX3CR1, migration and phagocytosis assays were evaluated. CX3CR1-deficient microglia showed impaired cell migration and deficiency of phagocytosis, as previously described for NRF2-deficient microglia, reinforcing the idea of the relevance of the CX3CL1/CX3CR1 axis in these events. The importance of these findings was evident in a tauopathy mouse model where the effects of sulforaphane (SFN), an NRF2 inducer, were examined on neuroinflammation in Cx3cr1 and Cx3cr1 mice. Interestingly, the treatment with SFN was able to modulate astrogliosis but failed to reduce microgliosis in Cx3cr1 mice. These findings suggest an essential role of the CX3CR1/NRF2 axis in microglial function and in tauopathies. Therefore, polymorphisms with loss of function in CX3CR1 or NRF2 have to be taken into account for the development of therapeutic strategies.
Ambient PM2.5 caused depressive-like responses through Nrf2/NLRP3 signaling pathway modulating inflammation
PM2.5 pollution has been associated with numerous adverse effects including cardiovascular, respiratory and metabolic diseases as well as emotional disorders. However, the potential mechanism has not known clearly. Twenty-four rats were divided into 3 groups and exposed to various airs: filtered air (FA), unfiltered air (UA) and concentrated PM2.5 air (CA), respectively. Thirty wild type (WT) and 30 Nrf2 knockout (KO) mice were divided into 2 groups and exposed to FA and UA, respectively. The changes of neurobehavioral function, neurotransmitter secretion, toxic elements deposition, oxidative stress and the inflammation in prefrontal cortex were investigated during 9-12 weeks with/without PM2.5 exposure. Results showed that CA rats and KO-UA mice emerged obviously depressive-like responses. Li, Be, Al, Cr, Co, Ni, Se, Cd, Ba, Ti and Pb could deposit in the prefrontal cortex of rats after PM2.5 exposure. The neurotransmitters were significantly disorder in prefrontal cortex of CA rats. The NLRP3 signaling pathway was more activated in Nrf2 than WT mice after PM2.5 exposure for 9 weeks. Nrf2/ NLRP3 signaling pathway modulating the inflammation might play an important role in the depression induced by ambient PM2.5.
Tomato Powder Modulates NF-B, mTOR, and Nrf2 Pathways during Aging in Healthy Rats
In the present study, we aimed to investigate the effects of tomato powder (TP) on glucose and lipid metabolism, as well as oxidative stress and the NF-B, mTOR, and Nrf2 pathways during the aging process in healthy rats.
Strigolactone GR24 upregulates target genes of the cytoprotective transcription factor Nrf2 in skeletal muscle
GR24 is a synthetic strigolactone analog, demonstrated to regulate the development of plants and arbuscular mycorrhizal fungi. GR24 possesses anti-cancer and anti-apoptotic properties, enhances insulin sensitivity and mitochondrial biogenesis in skeletal myotubes, inhibits adipogenesis, decreases inflammation in adipocytes and macrophages and downregulates the expression of hepatic gluconeogenic enzymes. Transcription factor Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) is a master regulator of antioxidant response, regulating a multitude of genes involved in cellular stress responses and anti-inflammatory pathways, thus maintaining cellular redox homeostasis. Nrf2 activation reduces the deleterious effects of mitochondrial toxins and has multiple roles in promoting mitochondrial function and dynamics. We studied the role of GR24 on gene expression in rat L6 skeletal muscle cells which were differentiated into myotubes. The myotubes were treated with GR24 and analyzed by microarray gene expression profiling. GR24 upregulated the cytoprotective transcription factor Nrf2 and its target genes, activating antioxidant defences, suggesting that GR24 may protect skeletal muscle from the toxic effects of oxidative stress.