NF-κB in liver diseases: a target for drug therapy

A First Metabolite Analysis of Norfolk Island Pine Resin and Its Hepatoprotective Potential to Alleviate Methotrexate (MTX)-Induced Hepatic Injury

Drug-induced liver injury (DILI) represents a significant clinical challenge characterized by hepatic dysfunction following exposure to diverse medications. Methotrexate (MTX) is a cornerstone in treating various cancers and autoimmune disorders. However, the clinical utility of MTX is overshadowed by its ability to induce hepatotoxicity. The current study aims to elucidate the hepatoprotective effect of the alcoholic extract of Egyptian Araucaria heterophylla resin (AHR) on MTX-induced liver injury in rats. AHR (100 and 200 mg/kg) significantly decreased hepatic markers (AST, ALT, and ALP), accompanied by an elevation in the antioxidant's markers (SOD, HO-1, and NQO1). AHR extract also significantly inhibited the TGF-β/NF-κB signaling pathway as well as the downstream cascade (IL-6, JAK, STAT-3, and cyclin D). The extract significantly reduced the expression of VEGF and p38 with an elevation in the BCL2 levels, in addition to a significant decrease in the IL-1β and TNF-α levels, with a prominent effect at a high dose (200 mg/kg). Using LC-HRMS/MS analysis, a total of 43 metabolites were tentatively identified, and diterpenes were the major class. This study presents AHR as a promising hepatoprotective agent through inhibition of the TGF-β/NF-κB and JAK/STAT3 pathways, besides its antioxidant and anti-inflammatory effects.

Allium sativum Essential Oil Supplementation Reverses the Hepatic Inflammation, Genotoxicity and Apoptotic Effects in Swiss Albino Mice Intoxicated with the Lead Nitrate

Prolonged lead (Pb) exposure impairs human health due to its interference with physiological and biochemical processes. Therefore, it is necessary to investigate natural therapeutics to alleviate Pb-induced intoxication. In the current investigation, essential oil extracted from the fresh bulbs of Allium sativum was considered as a natural remedy. Initially, in vitro antioxidant and anti-inflammatory activity of A. sativum essential oil (ASEO) were explored. The results reported that ASEO exhibits potent antioxidant and anti-inflammatory potential. Additionally, an in vivo study was conducted to elucidate its preventive role against Lead-nitrate (LN)-induced hepatic damage in Swiss albino mice. The experimental mice were allocated into six groups: Control, LN-intoxicated group (50 mg/kg), LN + ASEO (50 mg/kg), LN + ASEO (80 mg/kg), LN + Silymarin (25 mg/kg), and LN + vehicle oil control group. The entire duration of the study was of 30 days. From the results, it was determined that LN exposure elevated the Pb content in hepatic tissues which subsequently increased the serum biomarkers, inflammatory cytokines (NF-kB, TNF-α, IL-6) as well as apoptotic factors (caspase-3, BAX), all of which contribute to DNA damage. Meanwhile, it reduced anti-inflammatory (IFN-γ and IL-10) and anti-apoptotic factors (Bcl-2). Furthermore, Pb accumulation in hepatic tissues changed the histological architecture, which was linked to necrosis, central vein dilation, inflammatory cell infiltration and Kupffer cell activation. In contrast to this, ASEO administration decreased the Pb content, which in turn reduced the level of serum biomarkers, inflammatory and apoptotic factors. At the same time, it increased the anti-inflammatory and anti-apoptotic factors, thereby reduced DNA damage and restored the hepatic histology. In conclusion, exhaustive research is of the utmost demand to elucidate the precise defense mechanisms of ASEO against LN-induced hepatotoxicity.

Raspberry Ketone Prevents LPS-Induced Depression-Like Behaviors in Mice by Inhibiting TLR-4/NF-κB Signaling Pathway via the Gut-Brain Axis

SCOPE

Depression, a prevalent mental disorder, has significantly impacted the lives of 350 million people, yet it holds promise for amelioration through food-derived phenolics. Raspberries, renowned globally for their delectable flavor, harbor a phenolic compound known as raspberry ketone (RK). However, the impact of RK on depressive symptoms remains ambiguous. This study aims to investigate the impact of RK on lipopolysaccharide (LPS)-induced depressed mice and elucidates its potential mechanisms, focusing on the gut-brain axis.

METHODS AND RESULTS

Through behavioral tests, RK exerts a notable preventive effect on LPS-induced depression-like behaviors in mice. RK proves capable of attenuating gut inflammation, repairing gut barrier impairment, modulating the composition of the gut microbiome (Muribaculaceae, Streptococcus, Lachnospiraceae, and Akkermansia), and promoting the production of short-chain fatty acids. Furthermore, RK alleviates neuroinflammation by suppressing the TLR-4/NF-κB pathway and bolsters synaptic function by elevating levels of neurotrophic factors and synapse-associated proteins.

CONCLUSION

The current study provides compelling evidence that RK effectively inhibits the TLR-4/NF-κB pathway via the gut-brain axis, leading to the improvement of LPS-induced depression-like behaviors in mice. This study addresses the research gap in understanding the antidepressant effects of RK and illuminates the potential of utilizing RK as a functional food for preventing depression.

Resveratrol protects against Schistosoma mansoni-induced liver fibrosis by targeting the Sirt-1/NF-κB axis

Hepatic schistosomiasis is a prevalent form of chronic liver disease that drastically affects human health. Nevertheless, an antifibrotic drug that could suppress the development of hepatic fibrosis does not exist yet. The current study aimed to evaluate the effect of resveratrol, a natural polyphenol with multiple biological activities, on Schistosoma mansoni (S. mansoni)-induced hepatic fibrosis and delineate the underlying molecular mechanism. Swiss male albino mice were randomly assigned into infected and non-infected groups. Hepatic schistosomiasis infection was induced via exposure to S. mansoni cercariae. 6 weeks later, resveratrol was administrated either as 20 mg/kg/day or 100 mg/kg/day for 4 weeks to two infected groups. Another group received vehicle and served as infected control group. At the end of the study, portal hemodynamic, biochemical, and histopathological evaluation of liver tissues were conducted. Remarkably, resveratrol significantly reduced portal pressure, portal and mesenteric flow in a dose-dependent manner. It improved several key features of hepatic injury as evidenced biochemically by a significant reduction of bilirubin and liver enzymes, and histologically by amelioration of the granulomatous and inflammatory reactions. In line, resveratrol reduced the expression of pro-inflammatory markers; TNF-α, IL-1β and MCP-1 mRNA, together with fibrotic markers; collagen-1, TGF-β1 and α-SMA. Moreover, resveratrol restored SIRT1/NF-κB balance in hepatic tissues which is the main switch-off control for all the fibrotic and inflammatory mechanisms. Taken together, it can be inferred that resveratrol possesses a possible anti-fibrotic effect that can halt the progression of hepatic schistosomiasis via targeting SIRT1/ NF-κB signaling.

Scoparone inhibits the development of hepatocellular carcinoma by modulating the p38 MAPK/Akt/NF-κB signaling in nonalcoholic fatty liver disease mice

BACKGROUND AND STUDY AIM

The mechanisms underlying the progression of non-alcoholic fatty liver disease (NAFLD) into hepatocellular carcinoma (HCC) remains confusing and the therapeutics approaches are also challenging. Here, we aimed to investigate the effects of scoparone on the treatment of HCC stemmed from NAFLD and the underlying mechanisms.

MATERIALS AND METHODS

A model of NAFLD-HCC was created in mice, and these mice were treated with scoparone. Biochemical assays were conducted to assess the levels of biochemical markers. Tumors were evaluated through morphological examination. Histopathological analyses were performed using oil red O, Hematoxylin and Eosin, and Masson coloration assays. Immunohistochemistry (IHC) and RT-PCR were performed to analyze protein expression and measure mRNA expression levels, respectively.

RESULTS

Scoparone could ameliorate the pathological alterations observed in NAFLD-HCC mouse model. IHC analysis indicated an upregulation of NF-κB p65 expression in both NAFLD and NAFLD-HCC models, which was subsequently reverted by scoparone administration. Furthermore, scoparone treatment resulted in a reversal of the increased mRNA expression levels of NF-κB target genes, including TNF-α, MCP-1, iNOS, COX-2, NF-κB, and MMP-9, which were originally elevated in the NAFLD-HCC condition. Additionally, scoparone exhibited a capacity to counteract the activation of the MAPK/Akt signaling in the NAFLD-HCC model.

CONCLUSION

These findings suggest that scoparone holds promise as a potential therapeutic agent for NAFLD-associated HCC, and its model of action may involve the regulation of inflammatory pathways governed by the MAPK/Akt/NF-κB signaling cascade.

Curcumin and analogues in mitigating liver injury and disease consequences: From molecular mechanisms to clinical perspectives

BACKGROUND

Liver injury is a prevalent global health concern, impacting a substantial number of individuals and leading to elevated mortality rates and socioeconomic burdens. Traditional primary treatment options encounter resource constraints and high costs, prompting exploration of alternative adjunct therapies, such as phytotherapy. Curcumin demonstrates significant therapeutic potential across various medical conditions, particularly emerging as a promising candidate for liver injury treatment.

PURPOSE

This study aims to provide current evidence maps of curcumin and its analogs in the context of liver injury, covering aspects of biosafety, toxicology, and clinical trials. Importantly, it seeks to summarize the intricate mechanisms modulated by curcumin.

METHODS

We conducted a comprehensive search of MEDLINE, Web of Science, and Embase up to July 2023. Titles and abstracts were reviewed to identify studies that met our eligibility criteria. The screening process involved three authors independently assessing the potential of curcumin mitigating liver injury and its disease consequences by reviewing titles, abstracts, and full texts.

RESULTS

Curcumin and its analogs have demonstrated low toxicity in vitro and in vivo. However, the limited bioavailability has hindered their advanced use in liver injury. This limitation can potentially be addressed by nano-curcumin and emerging drug delivery systems. Curcumin plays a role in alleviating liver injury by modulating the antioxidant system, as well as cellular and molecular pathways. The specific mechanisms involve multiple pathways, such as NF-κB, p38/MAPK, and JAK2/STAT3, and the pro-apoptosis Bcl-2/Bax/caspase-3 axis in damaged cells. Additionally, curcumin targets nutritional metabolism, regulating the substance in liver cells and tissues. The microenvironment associated with liver injury, like extracellular matrix and immune cells and factors, is also regulated by curcumin. Initial evaluation of curcumin and its analogs through 12 clinical trials demonstrates their potential application in liver injury.

CONCLUSION

Curcumin emerges as a promising phytomedicine for liver injury owing to its effectiveness in hepatoprotection and low toxicity profile. Nevertheless, in-depth investigations are warranted to unravel the complex mechanisms through which curcumin influences liver tissues and overall physiological milieu. Moreover, extensive clinical trials are essential to determine optimal curcumin dosage forms, maximizing its benefits and achieving favorable clinical outcomes.

Protective Effects of Sitagliptin on Streptozotocin-Induced Hepatic Injury in Diabetic Rats: A Possible Mechanisms

Diabetes is a ubiquitous disease that causes several complications. It is associated with insulin resistance, which affects the metabolism of proteins, carbohydrates, and fats and triggers liver diseases such as fatty liver disease, steatohepatitis, fibrosis, and cirrhosis. Despite the effectiveness of Sitagliptin (ST) as an antidiabetic drug, its role in diabetes-induced liver injury is yet to be fully investigated. Therefore, this study aims to investigate the effect of ST on hepatic oxidative injury, inflammation, apoptosis, and the mTOR/NF-κB/NLRP3 signaling pathway in streptozotocin (STZ)-induced liver injury. Rats were allocated into four groups: two nondiabetic groups, control rats and ST rats (100 mg/kg), and two diabetic groups induced by STZ, and they received either normal saline or ST for 90 days. Diabetic rats showed significant hyperglycemia, hyperlipidemia, and elevation in liver enzymes. After STZ induction, the results revealed remarkable increases in hepatic oxidative stress, inflammation, and hepatocyte degeneration. In addition, STZ upregulated the immunoreactivity of NF-κB/p65, NLRP3, and mTOR but downregulated IKB-α in liver tissue. The use of ST mitigated metabolic and hepatic changes induced by STZ; it also reduced oxidative stress, inflammation, and hepatocyte degeneration. The normal expression of NF-κB/p65, NLRP3, mTOR, and IKB-α were restored with ST treatment. Based on that, our study revealed for the first time the hepatoprotective effect of ST that is mediated by controlling inflammation, oxidative stress, and mTOR/NF-κB/NLRP3 signaling.

Extracellular matrix turnover: phytochemicals target and modulate the dual role of matrix metalloproteinases (MMPs) in liver fibrosis

Extracellular matrix (ECM) resolution by matrix metalloproteinases (MMPs) is a well-documented mechanism. MMPs play a dual and complex role in modulating ECM degradation at different stages of liver fibrosis, depending on the timing and levels of their expression. Increased MMP-1 combats disease progression by cleaving the fibrillar ECM. Activated hepatic stellate cells (HSCs) increase expression of MMP-2, -9, and -13 in different chemicals-induced animal models, which may alleviate or worsen disease progression based on animal models and the stage of liver fibrosis. In the early stage, elevated expression of certain MMPs may damage surrounding tissue and activate HSCs, promoting fibrosis progression. At the later stage, downregulation of MMPs can facilitate ECM accumulation and disease progression. A number of phytochemicals modulate MMP activity and ECM turnover, alleviating disease progression. However, the effects of phytochemicals on the expression of different MMPs are variable and may depend on the disease models and stage, and the dosage, timing and duration of phytochemicals used in each study. Here, we review the most recent advances in the role of MMPs in the effects of phytochemicals on liver fibrogenesis, which indicates that further studies are warranted to confirm and define the potential clinical efficacy of these phytochemicals.

Anti-Angiogenic Effects of Natural Compounds in Diet-Associated Hepatic Inflammation

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are the most common causes of chronic liver disease and are increasingly emerging as a global health problem. Such disorders can lead to liver damage, resulting in the release of pro-inflammatory cytokines and the activation of infiltrating immune cells. These are some of the common features of ALD progression in ASH (alcoholic steatohepatitis) and NAFLD to NASH (non-alcoholic steatohepatitis). Hepatic steatosis, followed by fibrosis, lead to a continuous progression accompanied by angiogenesis. This process creates hypoxia, which activates vascular factors, initiating pathological angiogenesis and further fibrosis. This forms a vicious cycle of ongoing damage and progression. This condition further exacerbates liver injury and may contribute to the development of comorbidities, such as metabolic syndrome as well as hepatocellular carcinoma. Increasing evidence suggests that anti-angiogenic therapy may have beneficial effects on these hepatic disorders and their exacerbation. Therefore, there is a great interest to deepen the knowledge of the molecular mechanisms of natural anti-angiogenic products that could both prevent and control liver diseases. In this review, we focus on the role of major natural anti-angiogenic compounds against steatohepatitis and determine their potential therapeutic benefits in the treatment of liver inflammation caused by an imbalanced diet.

Investigation of the anti-oxidative and anti-inflammatory effects of melatonin on experimental liver damage by radiation

Radiotherapy is one of the inevitable treatment approaches for several types of cancer. We aimed to show the protective and therapeutic effects of daily use of melatonin on liver tissues subjected to a single dose of 10 Gy (gamma-ray) total body radiation. Rats were divided into 6 groups, of which 10 were in each: control, sham, melatonin, radiation, radiation+melatonin, and melatonin+radiation. The rats received 10 Gy of external radiation throughout their entire bodies. The rats were given 10 mg/kg/day of melatonin intraperitoneally before or after radiation treatment, depending on the group. Histological methods, immunohistochemical analysis (Caspase-3, Sirtuin-1, α-SMA, NF_ΚB-p65), biochemical analysis by ELİSA (SOD, CAT, GSH-PX, MDA, TNF-α, TGF-β, PDGF, PGC-1α) and the Comet assay as a marker of DNA damage were applied to the liver tissues. Histopathological examinations showed structural changes in the liver tissue of the radiation group. Radiation treatment increased the immunoreactivity of Caspase-3, Sirtuin-1 and α-SMA, but these effects were relatively attenuated in the melatonin-treated groups. The melatonin+radiation group had statistically significant results close to those of the control group, in terms of Caspase-3, NF_ΚB-p65 and Sirtuin-1 immunoreactivity. In melatonin treated groups, hepatic biochemical markers, MDA, SOD, TNF-α, TGF-β levels, and DNA damage parameters were decreased. Administration of melatonin before and after radiation has beneficial effects, but using it before radiation may be more efficient. Accordingly, daily melatonin usage could mitigate ionizing radiation induced damage.

The antioxidant and anti-inflammatory activities of caffeine effectively attenuate nonalcoholic steatohepatitis and thioacetamide-induced hepatic injury in male rats

The antioxidant effect of caffeine, associated with its ability to upregulate the nuclear factor-E2-related factor-2 (Nrf2)-signaling pathway, was explored as a possible mechanism for the attenuation of liver damage. Nonalcoholic steatohepatitis (NASH) was induced in rats by the administration of a high-fat, high-sucrose, high-cholesterol diet (HFSCD) for 15 weeks. Liver damage was induced in rats by intraperitoneal administration of thioacetamide (TAA) for six weeks. Caffeine was administered orally at a daily dose of 50 mg/kg body weight during the period of NASH induction to evaluate its ability to prevent disease development. Meanwhile, rats received TAA for three weeks, after which 50 mg/kg caffeine was administered daily for three weeks with TAA to evaluate its capacity to interfere with the progression of hepatic injury. HFSCD administration induced hepatic steatosis, decreased Nrf2 levels, increased oxidative stress, induced the activation of nuclear factor-κB (NF-κB), and elevated proinflammatory cytokine levels, leading to hepatic damage. TAA administration produced similar effects, excluding steatosis. Caffeine increased Nrf2 levels; attenuated oxidative stress markers, including malondialdehyde and 4-hydroxynonenal; restored normal, reduced glutathione levels; and reduced NF-κB activation, inflammatory cytokine levels, and damage. Our findings suggest that caffeine may be useful in the treatment of human liver diseases.

Acute liver injury induced by carbon tetrachloride reversal by Gandankang aqueous extracts through nuclear factor erythroid 2-related factor 2 signaling pathway

The aims of this study were to evaluated the effect and underlying mechanism of Gandankang (GDK) aqueous extract in alleviating the acute liver injury induced by carbon tetrachloride (CCl₄) in vivo and in vitro. Mice were divided into 5 groups (n = 8) for acute (Groups: control, 0.3 % CCl₄, BD (Bifendate), 1.17, 2.34 and 4.68 mg/kg GDK) liver injury study. 10 µL/g CCl₄ with corn oil were injected interperitoneally (i.p) expect the control group. HepG2 cells were used in vitro study. The results showed GDK can effectively inhibit liver damage and restore the structure and function of the liver. In mechanism, GDK inhibited CCl₄-induced liver fibrosis and blocked the NF-κB pathway to effectively inhibit the hepatic inflammatory response; and inhibited CCl₄-induced oxidative stress by upregulating the Keap1/Nrf2 pathway-related proteins and promoting the synthesis of several antioxidants. Additionally, it inhibited ferroptosis in the liver by regulating the expression of ACSl4 and GPX4. GDK reduced lipid peroxide generation in vitro by downregulating the production of reactive oxygen species and Fe²⁺ aggregation, thereby inhibiting ferroptosis and alleviating CCl₄-induced hepatocyte injury. In conclusion, we describe the potential complex mechanism underlying the effect of GDK against acute liver injury.

Activation of the NLRP3 inflammasome by CCl4 exacerbates hepatopathogenic diet-induced experimental NASH

INTRODUCTION AND OBJECTIVES

Administration of carbon tetrachloride (CCl₄), along with an hepatopathogenic diet, is widely employed as a chemical inducer to replicate human nonalcoholic steatohepatitis (NASH) in rodents; however, the role of the nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome in this model remains unclear. We aimed to determine the relevance of NLRP3 inflammasome activation in the development of NASH induced by CCl₄ along with an hepatopathogenic diet in male Wistar rats.

MATERIALS AND METHODS

Animals were fed either a high fat, sucrose, and cholesterol diet (HFSCD) or a HFSCD plus intraperitoneal injections of low doses of CCl₄ (400 mg/kg) once a week for 15 weeks. Liver steatosis, inflammation, fibrosis, and NLRP3 inflammasome activation were evaluated using biochemical, histological, ultrastructural, and immunofluorescence analyses, western blotting, and immunohistochemistry.

RESULTS

Our experimental model reproduced several aspects of the human NASH pathophysiology. NLRP3 inflammasome activation was induced by the combined effect of HFSCD plus CCl₄ and significantly increased levels of both proinflammatory and profibrogenic cytokines and collagen deposition in the liver; thus, NASH severity was higher in the HFSCD+CCl₄ group than that in the HFSCD group, to which CCl₄ was not administered. Hepatic stellate cells, the most profibrogenic cells, were activated by HFSCD plus CCl₄, as indicated by elevated levels of α-smooth muscle actin. Thus, activation of the NLRP3 inflammasome, triggered by low doses of CCl₄, exacerbates the severity of NASH.

CONCLUSIONS

Our results indicate that NLRP3 inflammasome activation plays a key role and may be an important therapeutic target for NASH treatment.

Free radicals, antioxidants, nuclear factor-E2-related factor-2 and liver damage

The liver performs various biochemical and molecular functions. Its location as a portal to blood arriving from the intestines makes it susceptible to several insults, leading to diverse pathologies, including alcoholic liver disease, viral infections, nonalcoholic steatohepatitis, and hepatocellular carcinoma, which are causes of death worldwide. Illuminating the molecular mechanism underlying hepatic injury will provide targets to develop new therapeutic strategies to fight liver maladies. In this regard, reactive oxygen species (ROS) are well-recognized mediators of liver damage. ROS induce nuclear factor-κB and the nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 inflammasome, which are the main proinflammatory signaling pathways that upregulate several proinflammatory and profibrogenic mediators. Additionally, oxygen-derived free radicals induce hepatic stellate cell activation to produce exacerbated quantities of extracellular matrix proteins, leading to fibrosis, cirrhosis and eventually hepatocellular carcinoma. Exogenous and endogenous antioxidants counteract the harmful effects of ROS, preventing liver necroinflammation and fibrogenesis. Therefore, several researchers have demonstrated that the administration of antioxidants, mainly derived from plants, affords beneficial effects on the liver. Notably, nuclear factor-E2-related factor-2 (Nrf2) is a major factor against oxidative stress in the liver. Increasing evidence has demonstrated that Nrf2 plays an important role in liver necroinflammation and fibrogenesis via the induction of antioxidant response element genes. The use of Nrf2 inducers seems to be an interesting approach to prevent/attenuate hepatic disorders, particularly under conditions where ROS play a causative role.

Mulberrin confers protection against hepatic fibrosis by Trim31/Nrf2 signaling

Mulberrin (Mul) is a key component of the traditional Chinese medicine Romulus Mori with various biological functions. However, the effects of Mul on liver fibrosis have not been addressed, and thus were investigated in our present study, as well as the underlying mechanisms. Here, we found that Mul administration significantly ameliorated carbon tetrachloride (CCl4)-induced liver injury and dysfunction in mice. Furthermore, CCl4-triggerd collagen deposition and liver fibrosis were remarkably attenuated in mice with Mul supplementation through suppressing transforming growth factor β1 (TGF-β1)/SMAD2/3 signaling pathway. Additionally, Mul treatments strongly restrained the hepatic inflammation in CCl4-challenged mice via blocking nuclear factor-κB (NF-κB) signaling. Importantly, we found that Mul markedly increased liver TRIM31 expression in CCl4-treated mice, accompanied with the inactivation of NOD-like receptor protein 3 (NLRP3) inflammasome. CCl4-triggered hepatic oxidative stress was also efficiently mitigated by Mul consumption via improving nuclear factor E2-related factor 2 (Nrf2) activation. Our in vitro studies confirmed that Mul reduced the activation of human and mouse primary hepatic stellate cells (HSCs) stimulated by TGF-β1. Consistently, Mul remarkably retarded the inflammatory response and reactive oxygen species (ROS) accumulation both in human and murine hepatocytes. More importantly, by using hepatocyte-specific TRIM31 knockout mice (TRIM31Hep-cKO) and mouse primary hepatocytes with Nrf2-knockout (Nrf2KO), we identified that the anti-fibrotic and hepatic protective effects of Mul were TRIM31/Nrf2 signaling-dependent, relieving HSCs activation and liver fibrosis. Therefore, Mul-ameliorated hepatocyte injury contributed to the suppression of HSCs activation by improving TRIM31/Nrf2 axis, thus providing a novel therapeutic strategy for hepatic fibrosis treatment.

Activation of transcription factor HIF inhibits IL-1β-induced NO production in primary cultured rat hepatocytes

Roxadustat and other hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHIs) have recently been approved for the treatment of chronic renal anemia. In macrophages and monocytes, the activation of HIF-1 by pro-inflammatory cytokines induces iNOS expression and activity through the NF-κB pathway to produce nitric oxide (NO), which causes liver injury when excessively produced. Few studies have reported a relationship between HIF activity and iNOS induction in hepatocytes. We investigated the effect of drug- and hypoxia-induced HIF activations on NO production in primary cultured rat hepatocytes. Roxadustat treatment and hypoxic conditions activated HIF. Contrary to expectations, HIF-PHI treatment and hypoxia inhibited IL-1β-induced NO production. RNA-Seq analysis of mRNA expression in rat hepatocytes showed that roxadustat treatment decreased the expression of genes related to inflammation, and genes in the NF-κB signaling pathway were induced by IL-1β. Moreover, roxadustat suppressed IL-1β-activated signaling pathways in an HIF-dependent manner. GalN/LPS-treated rats were used as in vivo models of hepatic injury, and roxadustat treatment showed a tendency to suppress the death of rats. Therefore, exogenous HIF-1 activation, including HIF-PHI and hypoxia exposures, suppressed IL-1β-induced iNOS mRNA expression and subsequent NO production in hepatocytes, by suppressing the NF-κB signaling pathway. Roxadustat treatment suppresses the expression of pro-inflammatory genes by activating HIF, and thus may exhibit hepatoprotective effects.

SIRT6 Activator UBCS039 Inhibits Thioacetamide-Induced Hepatic Injury In Vitro and In Vivo

SIRT6 has been reported to have multiple functions in inflammation and metabolism. In the present study, we explored the regulatory effects and mechanisms of SIRT6 in thioacetamide (TAA)-induced mice acute liver failure (ALF) models. The SIRT6 activator UBCS039 was used in this animal and cell experiments. We observed that UBCS039 ameliorated liver damage, including inflammatory responses and oxidative stress. Further study of mechanisms showed that the upregulation of SIRT6 inhibited the inflammation reaction by suppressing the nuclear factor-κB (NF-κB) pathway in the TAA-induced ALF mice model and lipopolysaccharide-stimulated macrophages. In addition, the upregulation of SIRT6 alleviated oxidative stress damage in hepatocytes by regulating the Nrf2/HO-1 pathway. These findings demonstrate that pharmacologic activator of SIRT6 could be a promising target for ALF.

Hepatoprotective and therapeutic effects of resveratrol: A focus on anti-inflammatory and anti- oxidative activities

Being the most essential organ in the body, the liver performs critical functions. Hepatic disorders, such as alcoholic liver disease, hepatic steatosis, liver fibrosis, non-alcoholic fatty liver disease, hepatocellular carcinoma and hepatic failure, have an impact on the biochemical and physiological functions of the body. The main representative of the flavonoid subgroup of flavones, Resveratrol (RES), exhibits suitable pharmacological activities for treating various liver diseases, such as fatty hepatitis, liver steatosis, liver cancer and liver fibrosis. According to various studies, grapes and red wine are good sources of RES. RES has various health properties; it is anti-inflammatory, anti-apoptotic, anti-oxidative and hepatoprotective against several hepatic diseases and hepatoxicity. Therefore, we performed a thorough research and created a summary of the distinct targets of RES in various stages of liver diseases. We concluded that RES inhibited liver inflammation essentially by causing a significant decrease in the expression of various pro-inflammatory cytokines like TNF-α, IL-1α, IL-1β, and IL-6. It also inhibits the transcription factor nuclear NF-κB that brings about the inflammatory cascade. RES also inhibits the PI3K/Akt/mTOR pathway to induce apoptosis. Additionally, it reduces oxidative stress in hepatic tissue by markedly reducing MDA and NO contents, and significantly increasing the levels of CAT, SOD and reduced GSH, in addition to AST and ALT, against toxic chemicals like CC14, As2O3 and TTA. Due to its anti-oxidant, anti-inflammatory and anti-fibrotic properties, RES reduces liver injury markers. RES is safe natural antioxidant that provides pharmacological rectification of the hepatoxicity of toxic chemicals.

In-depth hepatoprotective mechanistic study of Echinacea purpurea flowers: In vitro and in vivo studies

Introduction: Echinacea purpurea is a flowering plant commonly used as an herbal medicine despite insufficient scientific bases to validate its usage. The present study aimed to examine in vitro and in vivo hepatoprotective effects of aqueous and alcoholic extracts of E. purpurea flowers. Methods: In vitro protection against hepato-cytotoxicity was carried out on human HepG-2 cells using colorimetric tetrazolium (MTT) assay, while the in vivo hepatoprotective activity was studied against carbon-tetrachloride (CCl4) induced acute hepatotoxicity in rats. Results: The results revealed that the extracts of E. purpurea induced discernable in vitro protection on HepG-2 cells and in vivo against CCl4 induced hepatotoxicity. Both extracts were significantly able to restore the serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin, total protein, and albumin to normal levels compared to the CCl4 intoxicated group. In addition, the extracts markedly mitigated the oxidative stress by decreasing Malondialdehyde (MDA) and increasing superoxide dismutase (SOD) and glutathione (GSH) markers compared to the CCl4 intoxicated group. It was also associated with the down-regulation of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels in liver tissues. Histopathological examination revealed a decrease in hepatocytes’ degenerative changes and noticeable improvement of the liver damage by extracts of E. purpurea. Conclusion: These findings have proven that aqueous and alcoholic extracts of E. purpurea flowers have a significant hepatoprotective effect, probably owing to antioxidant, anti-inflammatory activities, and regulating apoptotic-related genes. This confirms the ethnomedicinal uses of E. purpurea in patients suffering from liver diseases.

Naringenin alleviates hepatic injury in zinc oxide nanoparticles exposed rats: impact on oxido-inflammatory stress and apoptotic cell death

Human exposure to nanoparticles became unavoidable secondary to their massive involvement in a multitude of industrial applications. Zinc oxide nanoparticles (ZnONPs) are one of the most commonly used metal oxide nanoparticles in biological applications. Naringenin (NAR), a citrus-derived flavonoid, has favorable biological properties that promote human health. The present study was carried out to investigate the possible defensive role of NAR versus ZnONPs provoked hepatic injury in rats through an evaluation of liver enzymes, hepatic biomarkers of oxidative stress, inflammatory process, apoptotic cell death along with histopathological examination of liver tissue. Therefore, 32 adult rats were randomly divided into four equal groups as control, NAR, ZnONPs and co-treated ZnONPs with NAR groups. All treatments were administered for 14 days. Our results showed that ZnONPs induced hepatic injury as documented by the marked increased in hepatic enzymes activities, disturbed hepatic oxidant/antioxidant balance, increased hepatic inflammatory reactions, in addition to, extensive hepatic morphological alterations, marked collagen fibers accumulation as well as overexpression of apoptotic BAX and the noticeable intensified positive nuclear staining for nuclear factor Kabba-b in hepatic tissues. Concurrent NAR supplement to ZnONPs- treated rats significantly declined liver enzymes activities, restored oxidant/antioxidant balance, reversed inflammation, induced fewer collagen fibers accumulation, and antagonized BAX-mediated apoptotic cell death in hepatic tissues. We concluded that concurrent NAR supplement to ZnONPs treated rats improved hepatic function and structure by its antioxidant, anti-inflammatory and antiapoptotic potentials.

Inflammation response after the cessation of chronic arsenic exposure and post-treatment of natural astaxanthin in liver: potential role of cytokine-mediated cell-cell interactions

Ongoing groundwater arsenic contamination throughout China was first recognized in the 1960s. Groundwater arsenic contamination is a high risk for human and animal health worldwide. Apart from drinking water, diet is the second pathway for arsenic to enter the human body and eventually cause liver injury. Natural astaxanthin extracted from the green algae Haematococcus pluvialis has dominated the nutraceutical market for potential health benefits. Nevertheless, the molecular mechanism underlying the protective effect post astaxanthin against arsenic-induced hepatotoxicity remains largely obscure. In this study, we investigate the effect of natural astaxanthin (derived from Haemotococcus pluvialis) on oxidative stress and liver inflammatory response in rats after the cessation of chronic arsenic exposure. Wistar rats were given astaxanthin (250 mg kg-1) daily for 2 weeks after the cessation of exposure to sodium arsenite (300 μg L-1, drinking water, 24 weeks) by intragastric administration. The results showed that post treatment with astaxanthin attenuated liver injury induced by long-term exposure to arsenic in rats. Most importantly, post treatment with astaxanthin decreased the increasing of inflammatory cytokine NF-κB, tumor necrosis factor-α, interleukin-1β, oxidative stress level, and total arsenic content in livers of rats exposed to arsenic. In addition, post treatment with astaxanthin reversed the increasing of protein levels of alpha-smooth muscle actin and collagen Iα1, which are the activation markers of hepatic stellate cells (HSCs). Collectively, these data demonstrate that post astaxanthin treatment attenuates inflammation response in the liver after the cessation of chronic arsenic exposure via inhibition of cytokine-mediated cell-cell interactions. Daily ingestion of natural astaxanthin might be a potential and beneficial candidate for the treatment of liver damage after the cessation of chronic exposure to sodium arsenite.

Citrus peel derived' Poly-Methoxylated Flavones (PMF)

The prevalence of obesity has increased substantially over the last several decades and several environmental factors have accelerated this trend. Poly-methoxy flavones (PMFs) exist abundantly in the peels of citrus, and their biological activities have been broadly examined in recent years. Several studies have examined the effects of PMFs on obesity and its-related diseases. This systematic review conducted to focus on the effect of PMFs on obesity and its related conditions management. The PubMed, Google Scholar, Scopus, and Science Direct databases were searched for relevant studies published before November 2020. Out of 1,615 records screened, 16 studies met the study criteria. The range of dosage of PMFs was varied from 10 to 200 mg/kg (5-26 weeks) and 1-100 μmol (2h-8 days) across selected animal and in vitro studies, respectively. The literature reviewed shows that PMFs modulate several biological processes associated with obesity such as lipid and glucose metabolism, inflammation, energy balance, and oxidative stress by different mechanisms. All of the animal studies showed significant positive effects of PMFs on obesity by reducing body weight (e.g. reduced weight gain by 21.04%), insulin resistance, energy expenditure, inhibiting lipogenesis and reduced blood lipids (e.g. reduced total cholesterol by 23.10%, TG by 44.35% and LDL by 34.41%). The results of the reviewed in vitro studies have revealed that treatment with PMFs significantly inhibits lipid accumulation in adipocytes (e.g. reduced lipid accumulation by 55-60%) and 3T3-L1 pre-adipocyte differentiation as well by decreasing the expression of PPARγ and C/EBPα and also reduces the number and size of fat cells and reduced TG content in adipocytes by 45.67% and 23.10% and 16.08% for nobiletin, tangeretin and hesperetin, respectively. Although current evidence supports the use of PMFs as a complementary treatment in obesity, future research is needed to validate this promising treatment modality.

A review on the protective effects of naringenin against natural and chemical toxic agents

Naringenin (NRG), as a flavanone from flavonoids family, is widely found in grapefruit, lemon tomato, and Citrus fruits. NRG has shown strong anti-inflammatory and antioxidant activities in body organs via mechanisms such as enhancement of glutathione S-transferase (GST), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activity, but reduction of serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and malondialdehyde (MDA). Furthermore, NRG anti-apoptotic potential was indicated to be mediated by regulating B-cell lymphoma (Bcl-2), Bcl-2-associated X protein (Bax) and caspase3/9. Overall, these properties make NRG a highly fascinating compound with beneficial pharmacological effects. Based on the literature, NRG-induced protective effects against toxicities produced by natural toxins, pharmaceuticals, heavy metals, and environmental chemicals, were mainly mediated via suppression of lipid peroxidation, oxidative stress (through boosting the antioxidant arsenal), and inflammatory factors (e.g., TNF-α, interleukin [IL]-6, IL-10, and IL-12), and activation of PI3K/Akt and MAPK survival signaling pathways. Despite considerable body of evidence on protective properties of NRG against a variety of toxic compounds, more well-designed experimental studies and particularly, clinical trials are required before reaching a concrete conclusion. The present review discusses how NRG protects against the above-noted toxic compounds.

Protective Effect of Oligonol on Dimethylnitrosamine-Induced Liver Fibrosis in Rats via the JNK/NF-κB and PI3K/Akt/Nrf2 Signaling Pathways

Oligonol is a low molecular weight polyphenol product derived from lychee fruit by a manufacturing process. We investigated oligonol’s anti-fibrotic effect and the underlying mechanism in dimethylnitrosamine (DMN)-induced chronic liver damage in male Sprague–Dawley rats. Oral administration of oligonol (10 and 20 mg/kg body weight) ameliorated the DMN-induced abnormalities in liver histology and serum parameters in rats. Oligonol prevented the DMN-induced elevations of TNF-α, IL-1β, IL-6, cyclooxygenase-2, and inducible nitric oxide synthase expressions at the mRNA level. NF-κB activation and JNK phosphorylation in DMN-treated rats were ablated by oligonol. Oligonol reduced the enhanced production of hepatic malondialdehyde and reactive oxygen species and recovered protein SH, non-protein SH levels, and catalase activity in the DMN treated liver. Nrf2 translocation into the nucleus was enhanced, and PI3K and phosphorylated Akt levels were increased by administering oligonol. The level of hepatic fibrosis-related factors such as α-smooth muscle actin, transforming growth factor-β1, and type I collagen was reduced in rats treated with oligonol. Histology and immunohistochemistry analysis showed that the accumulation of collagen and activation of hepatic stellate cells (HSCs) in liver tissue were restored by oligonol treatment. Taken together, oligonol showed antioxidative, hepatoprotective, and anti-fibrotic effects via JNK/NF-κB and PI3K/Akt/Nrf2 signaling pathways in DMN-intoxicated rats. These results suggest that antioxidant oligonol is a potentially useful agent for the protection against chronic liver injury.

Curcumin Can be Acts as Effective agent for Prevent or Treatment of Alcohol-induced Toxicity in Hepatocytes: An Illustrated Mechanistic Review

Previous studies have shown that alcohol abuse can cause serious liver damage and cirrhosis. The main pathway for these types of hepatocellular cell neurodegeneration is mitochondrial dysfunction, which causes lipid peroxidation and dysfunction of the glutathione ring and the defect of antioxidant enzymes in alcoholic hepatic cells. Alcohol can also initiate malicious inflammatory pathways and trigger the initiation and activation of intestinal and extrinsic apoptosis pathways in hepatocellular tissues that lead to cirrhosis. Previous studies have shown that curcumin may inhibit lipid peroxidation, glutathione dysfunction and restore antioxidant enzymes. Curcumin also modulates inflammation and the production of alcohol-induced biomarkers. Curcumin has been shown to play a critical role in the survival of alcoholic hepatocellular tissue. It has been shown that curcumin can induce and trigger mitochondrial biogenesis and, by this mechanism, prevent the occurrence of both intrinsic and extrinsic apoptosis pathways in liver cells that have been impaired by alcohol. According to this mechanism, curcumin may protect hepatocellular tissue from alcohol-induced cell degeneration and may therefore survive alcoholic hepatocellular tissue. . Based on these mechanisms, the protective functions of curcumin against alcohol-induced cell degeneration due to oxidative stress, inflammation, and apoptosis events in hepatocellular tissue have been recorded. Hence, in this research, we have attempted to evaluate and analyze the main contribution mechanism of curcumin cell defense properties against alcohol-induced hepatocellular damage, according to previous experimental and clinical studies, and in this way we report findings from major studies.

Standardized ethanol extract of Tinospora crispa upregulates pro-inflammatory mediators release in LPS-primed U937 human macrophages through stimulation of MAPK, NF-κB and PI3K-Akt signaling networks

BACKGROUND

Immunomodulatory effects of Tinospora crispa have been investigated due to its traditional use to treat several inflammatory disorders associated to the immune system. The present study reports the underlying mechanisms involved in the stimulation of 80% ethanol extract of T. crispa stems on pro-inflammatory mediators release in lipopolysaccharide (LPS)-primed U937 human macrophages via MyD88-dependent pathways.

METHODS

Release of interleukin (IL)-1β and tumor necrosis factor (TNF)-α, and production of prostaglandin E₂ (PGE₂) were determined by using enzyme-linked immunosorbent assay (ELISA). Immunoblot technique was executed to determine the activation of MAPKs molecules, NF-κB, PI3K-Akt and cyclooxygenase-2 (COX-2) protein. Determination of pro-inflammatory cytokines and COX-2 relative gene expression levels was by performing the real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). A reversed-phase HPLC method was developed and validated to standardize the T. crispa extract and chemical profiling of its secondary metabolites was performed by LC-MS/MS.

RESULTS

Qualitative and quantitative analyses of chromatographic data indicated that syringin and magnoflorine were found as the major components of the extract. T. crispa-treatment prompted activation of NF-κB by enhancing IKKα/β and NF-κB (p65) phosphorylation, and degradation of IκBα. The extract upregulated COX-2 protein expression, release of pro-inflammatory mediators and MAPKs (ERK, p38 and JNK) phosphorylation as well as Akt dose-dependently. T. crispa extract also upregulated the upstream signaling adaptor molecules, toll-like receptor 4 (TLR4) and MyD88. T. crispa-treatment also upregulated the pro-inflammatory markers mRNA expression.

CONCLUSION

The results suggested that T. crispa extract stimulated the MyD88-dependent signaling pathways by upregulating the various immune inflammatory related parameters.

An aqueous extract of Stevia rebaudiana variety Morita II prevents liver damage in a rat model of cirrhosis that mimics the human disease

INTRODUCTION AND AIM

Stevia has exhibited antioxidant, antihyperglycemic, antihypertensive and anti-inflammatory properties in several in vivo and in vitro models. The objective of this study was to investigate the ability of an aqueous extract of stevia (AES) to prevent experimental cirrhosis in rats and to explore its mechanism of action.

MATERIALS AND METHODS

Liver cirrhosis was induced by administering carbon tetrachloride (CCl₄) (400mg/kg by i.p. injection 3 times a week for 12 weeks); AES was administered (100mg/kg by gavage daily) during the CCl₄ treatment. Fibrosis was evaluated with histological, biochemical and molecular approaches, and liver damage was assessed with standardized procedures. The profibrotic pathways were analyzed by western blotting, qRT-PCR and immunohistochemistry.

RESULTS AND CONCLUSIONS

Chronic CCl₄ administration increased nuclear factor kappa B (NF-κB) and proinflammatory cytokine production as well as oxidative parameters such as lipid peroxidation and 4-hydroxynonenal levels, whereas GSH and nuclear factor-E2-related factor 2 (Nrf2) levels were decreased. CCl₄ induced profibrogenic mediator expression, hepatic stellate cell (HSC) activation and, consequently, extracellular matrix production. AES exhibited antioxidant, anti-inflammatory and antifibrotic properties, probably because of its capacity to induce Nrf2 expression, reduce NF-κB expression and block several profibrogenic signaling pathways, subsequently inhibiting HSC activation and preventing fibrosis induced by chronic CCl₄ administration.

Synergistic Effects of Curcumin and 5-Fluorouracil on the Hepatocellular Carcinoma In vivo and vitro through regulating the expression of COX-2 and NF-κB

Curcumin (CU) has shown broad anti-cancer effects. 5-fluorouracil (5-FU) has been a conventional chemotherapeutic agent for hepatocellular carcinoma. Unfortunately, the nonspecific cytotoxicity and multidrug resistance caused by long-term use limited the clinical efficacy of 5-FU. This study was aimed to investigate whether the combination of CU and 5-FU could generate synergistic effect in inhibiting the human hepatocellular carcinoma. The results of cytotoxicity test showed that compared with applying single drugs, the combination of CU and 5-FU (1:1, 1:2, 1:4, 2:1 and 4:1, mol/mol) presented stronger cytotoxicity in SMMC-7721, Bel-7402, HepG-2 and MHCC97H cells, while the combination groups are relatively insensitive to normal hepatocytes (L02). Among them, the molar ratio of 2:1 combination group showed strong synergistic effect in SMMC-7721cells. Then, western blotting assay further verified that the mechanism of the synergistic effect may be related to the inhibition of the expression of NF-κB (overall) and COX-2 protein. In addition, the synergistic effect was also validated in the xenograft mice in vivo. This research not only provides a novel and effective combination strategy for the therapy of hepatocellular carcinoma but also provides an experimental basis for the development of CU and 5-FU compound preparation.

Liver Fibrosis: Mechanistic Concepts and Therapeutic Perspectives

Liver fibrosis due to viral or metabolic chronic liver diseases is a major challenge of global health. Correlating with liver disease progression, fibrosis is a key factor for liver disease outcome and risk of hepatocellular carcinoma (HCC). Despite different mechanism of primary liver injury and disease-specific cell responses, the progression of fibrotic liver disease follows shared patterns across the main liver disease etiologies. Scientific discoveries within the last decade have transformed the understanding of the mechanisms of liver fibrosis. Removal or elimination of the causative agent such as control or cure of viral infection has shown that liver fibrosis is reversible. However, reversal often occurs too slowly or too infrequent to avoid life-threatening complications particularly in advanced fibrosis. Thus, there is a huge unmet medical need for anti-fibrotic therapies to prevent liver disease progression and HCC development. However, while many anti-fibrotic candidate agents have shown robust effects in experimental animal models, their anti-fibrotic effects in clinical trials have been limited or absent. Thus, no approved therapy exists for liver fibrosis. In this review we summarize cellular drivers and molecular mechanisms of fibrogenesis in chronic liver diseases and discuss their impact for the development of urgently needed anti-fibrotic therapies.

Silymarin as Supportive Treatment in Liver Diseases: A Narrative Review

Silymarin, an extract from milk thistle seeds, has been used for centuries to treat hepatic conditions. Preclinical data indicate that silymarin can reduce oxidative stress and consequent cytotoxicity, thereby protecting intact liver cells or cells not yet irreversibly damaged. Eurosil 85® is a proprietary formulation developed to maximize the oral bioavailability of silymarin. Most of the clinical research on silymarin has used this formulation. Silymarin acts as a free radical scavenger and modulates enzymes associated with the development of cellular damage, fibrosis and cirrhosis. These hepatoprotective effects were observed in clinical studies in patients with alcoholic or non-alcoholic fatty liver disease, including patients with cirrhosis. In a pooled analysis of trials in patients with cirrhosis, silymarin treatment was associated with a significant reduction in liver-related deaths. Moreover, in patients with diabetes and alcoholic cirrhosis, silymarin was also able to improve glycemic parameters. Patients with drug-induced liver injuries were also successfully treated with silymarin. Silymarin is generally very well tolerated, with a low incidence of adverse events and no treatment-related serious adverse events or deaths reported in clinical trials. For maximum benefit, treatment with silymarin should be initiated as early as possible in patients with fatty liver disease and other distinct liver disease manifestations such as acute liver failure, when the regenerative potential of the liver is still high and when removal of oxidative stress, the cause of cytotoxicity, can achieve the best results.

Conformational states of TNFR1 as a molecular switch for receptor function

Tumor necrosis factor receptor 1 (TNFR1) is a transmembrane receptor that plays a key role in the regulation of the inflammatory pathway. While inhibition of TNFR1 has been the focus of many studies for the treatment of autoimmune diseases such as rheumatoid arthritis, activation of the receptor is important for the treatment of immunodeficiency diseases such as HIV and neurodegenerative diseases such as Alzheimer's disease where a boost in immune signaling is required. In addition, activation of other TNF receptors such as death receptor 5 or FAS receptor is important for cancer therapy. Here, we used a previously established TNFR1 fluorescence resonance energy transfer (FRET) biosensor together with a fluorescence lifetime technology as a high-throughput screening platform to identify a novel small molecule that activates TNFR1 by increasing inter-monomeric spacing in a ligand-independent manner. This shows that the conformational rearrangement of pre-ligand assembled receptor dimers can determine the activity of the receptor. By probing the interaction between the receptor and its downstream signaling molecule (TRADD) our findings support a new model of TNFR1 activation in which varying conformational states of the receptor act as a molecular switch in determining receptor function.

Demethyleneberberine attenuates concanavalin A-induced autoimmune hepatitis in mice through inhibition of NF-κB and MAPK signaling

Demethyleneberberine (DMB) is a natural product which has been reported to possess mitochondria-targeting anti-oxidative and anti-inflammatory effect. However, the pharmacological action and molecular mechanism of DMB on autoimmune hepatitis (AIH) have not been explored. In this study, AIH was induced by intravenously injecting Con A (20 mg/kg) in mice for 8 h, and DMB protected against Con A-induced AIH, evidenced by obvious reduction of hepatic enzymes in serum and histological lesion. DMB significantly inhibited the infiltration of CD4⁺ T cell and Kupffer cell as well as the expression of inflammatory cytokines, such as TNF-α, IL-6, IL-1β and IFN-γ by ELISA and qPCR analysis. Western blotting analysis illustrated that DMB remarkably inhibited Con A-induced phosphorylation of IKK, IκB, NF-κB p65, ERK, JNK, p38 MAPK and STAT3 induced by Con A. Moreover, DMB also effectively suppressed hepatic oxidative stress with reduction of MDA and elevation of GSH. Taken together, our findings indicated that DMB could prevent Con A-induced AIH by regulating NF-κB and MAPK signaling, suggesting that DMB can serve as a promising candidate for therapy of AIH.

Mechanistic aspects of antifibrotic effects of honokiol in Con A-induced liver fibrosis in rats: Emphasis on TGF-β/SMAD/MAPK signaling pathways

Aim Liver fibrosis represents a massive global health burden with limited therapeutic options. Thus, the need for curative options is evident. Thus, this study aimed to assess the potential antifibrotic effect of honokiol in Concanavalin A (Con A) induced immunological model of liver fibrosis as well the possible underlying molecular mechanisms.

METHODS

Male Sprague-Dawley rats were treated with either Con A (20 mg/kg, IV) and/or honokiol (10 mg/kg, orally) for 4 weeks. Hepatotoxicity indices were as well as histopathological evaluation was done. Hepatic fibrosis was assessed by measuring alpha smooth muscle actin (α-SMA) expression and collagen fibers deposition by Masson's trichrome stain and hydroxyproline content. To elucidate the underlying molecular mechanisms, the effect of honokiol on oxidative stress, inflammatory markers as well as transforming growth factor beta (TGF-β)/SMAD and mitogen-activated protein kinase (MAPK) pathways was assessed.

KEY FINDINGS

Honokiol effectively reversed the hepatotoxicity indices elevations and abnormal histopathological changes induced by Con A. Besides, honokiol attenuated Con A-induced liver fibrosis by down-regulation of hydroxyproline levels, α-SMA expression together with a marked decrease in collagen fibers deposition. Mechanistically Con A induced oxidative stress, provocation of inflammatory responses and activation of TGF-β/SMAD/MAPK pathways. Contrariwise, honokiol co-treatment significantly restored antioxidant defence mechanisms, down-regulated inflammatory cascades and inhibited TGF-β/SMAD/MAPK signaling pathways.

CONCLUSION

The results provide an evidence for the promising antifibrotic effect of honokiol that could be partially due to suppressing oxidative stress and inflammatory processes as well as inhibition of TGF-β/SMAD/MAPK signaling pathways.

Resveratrol treatment in patients with polycystic ovary syndrome decreased pro-inflammatory and endoplasmic reticulum stress markers

PROBLEM

Polycystic ovary syndrome (PCOS) is associated with endoplasmic reticulum (ER) stress and pro-inflammatory condition. The aim of the present study was to evaluate the effect of resveratrol treatment on pro-inflammatory and ER stress markers in patients with PCOS.

METHOD OF STUDY

Cumulus cells were obtained from 40 patients with PCOS who were divided into two groups: placebo and resveratrol treatment (receiving 800 mg/d for 40 days) groups. Blood samples were obtained from all patients before and after the procedure to evaluate interleukin (IL)-6, IL-1β, IL-18, TNF-α, NF-κB, and C-reactive protein (CRP). Total RNA was extracted from cumulus cells, and cDNA was synthesized by reverse transcription. Expressions of five genes in ER stress response pathway (ATF4, ATF6, CHOP, GRP78, and XBP1s) were assessed with quantitative real-time PCR. Statistical analysis was performed with Student's t test.

RESULTS

After treatment with resveratrol, it was found that serum levels of IL-6, IL-1β, TNF-α, IL-18, NF-κB, and CRP decreased in the treatment group. In addition, gene expression results showed that the expression levels of ATF4 (P < .05) and ATF6 (P < .001) significantly increased in the resveratrol treatment group, while the expression levels of CHOP, GRP78, and XBP1 (P < .001 for all) significantly decreased.

CONCLUSION

Results demonstrated that resveratrol has anti-inflammatory effects through the suppression of NF-κB and NF-κB-regulated gene products. On the other hand, resveratrol can modulate ER stress in granulosa cells (GCs) by altering the expression of genes involved in unfolding protein response (UPR) process. Our findings suggest that ER stress is a potential therapeutic target for patients with PCOS.

Hepatoprotective and anti-inflammatory effects of total flavonoids of Qu Zhi Ke (peel of Citrus changshan-huyou) on non-alcoholic fatty liver disease in rats via modulation of NF-κB and MAPKs

BACKGROUND

Citrus flavonoids, consisting of naringin, narirutin, neohesperidine, etc., have therapeutic activities for the treatment of lipometabolic disorders. The peel of Citrus changshan-huyou (Qu Zhi Ke, QZK) is a new source of flavonoids, but attracted little attention so far.

HYPOTHESIS

QZK should possess therapeutic effects against lipometabolic disorders due to the flavonoids it contains.

STUDY DESIGN

In this study, we extracted and purified the flavonoids of QZK (TFCH) and established an obesity-induced non-alcoholic fatty liver disease (NAFLD) model of rats. TFCH was given orally for 8 weeks, and its anti-NAFLD effects and potential mechanism were evaluated.

METHODS

The flavonoid chemoprofile of TFCH was determined by using HPLC. High-fat diet was employed to induce NAFLD model in rats, and six groups were set up: negative control group, reference treatment group, model group, low-dose TFCH (25 mg/kg), intermediate-dose TFCH (50 mg/kg), and high-dose TFCH (100 mg/kg). Serum and liver levels of inflammatory cytokines and NAFLD markers were measured biochemically. The relative mRNA expressions of liver T-bet, GATA3, and TNF-α were tested by real time PCR (qPCR) analysis. The protein expression of p38 and the phosphorylation of NF-κB, ERK1/2, and p38 in liver were tested by Western blot analysis.

RESULTS

The histopathological observation showed that TFCH attenuated hepatic lesions with significantly decreased NAFLD activity scores. The biochemical data showed that TFCH significantly suppressed both systemic and intrahepatic inflammation by inhibiting IL-1β, IL-6, IL-12, TNF-α, and IFN-γ, and the qPCR analysis revealed a Th1/Th2 related anti-inflammatory mechanism of TFCH. Western blot results clarified that TFCH exerted hepatoprotective and anti-inflammatory effects by suppression of phosphorylated NF-κB and MAPKs, indicating a mechanism associated with NF-κB and MAPK signaling pathways.

CONCLUSION

QZK is a new source of Citrus flavonoids for therapeutic use, and TFCH is a promising representative of Citrus flavonoids for anti-NAFLD therapy.

Naringenin attenuates the progression of liver fibrosis via inactivation of hepatic stellate cells and profibrogenic pathways

There is no effective treatment for hepatic fibrosis. Previously, we demonstrated that naringenin possesses the ability to prevent experimental chronic liver damage. Therefore, the objective of this work was to investigate whether naringenin could reverse carbon tetrachloride (CCl₄)-induced fibrosis in rats and, if so, to search for the mechanisms involved. CCl₄ was given to male Wistar rats (400 mg/kg, three times per week, i. p.) for 12 weeks; naringenin (100 mg/kg twice per day, p. o.) was administered from weeks 9-12 of the CCl₄ treatment. Liver damage and oxidative stress markers were measured. Masson's trichrome, hematoxylin-eosin staining and immunohistochemistry were performed. Zymography assays for MMP-9 and MMP-2 were carried out. TGF-β, CTGF, Col-I, MMP-13, NF-κB, IL-1β, IL-10, Smad7, pSmad3 and pJNK protein levels were determined by western blotting. In addition, α-SMA and Smad3 protein and mRNA levels were studied. Naringenin reversed liver damage, biochemical and oxidative stress marker elevation, and fibrosis and restored normal MMP-9 and MMP-2 activity. The flavonoid also preserved NF-κB, IL-1β, IL-10, TGF-β, CTGF, Col-I, MMP-13 and Smad7 protein levels. Moreover, naringenin decreased JNK activation and Smad3 phosphorylation in the linker region. Finally, α-SMA and Smad3 protein and mRNA levels were reduced by naringenin administration. The results of this study demonstrate that naringenin blocks oxidative stress, inflammation and the TGF-β-Smad3 and JNK-Smad3 pathways, thereby carrying out its antifibrotic effects and making it a good candidate to treat human fibrosis, as previously demonstrated in toxicological and clinical studies.

Free radicals, antioxidants, nuclear factor-E2-related factor-2 and liver damage

Oxidative/nitrosative stress is proposed to be a critical factor in various diseases, including liver pathologies. Antioxidants derived from medicinal plants have been studied extensively and are relevant to many illnesses, including liver diseases. Several hepatic disorders, such as viral hepatitis and alcoholic or nonalcoholic steatohepatitis, involve free radicals/oxidative stress as agents that cause or at least exacerbate liver injury, which can result in chronic liver diseases, such as liver fibrosis, cirrhosis and end-stage hepatocellular carcinoma. In this scenario, nuclear factor-E2-related factor-2 (Nrf2) appears to be an essential factor to counteract or attenuate oxidative or nitrosative stress in hepatic cells. In fact, a growing body of evidence indicates that Nrf2 plays complex and multicellular roles in hepatic inflammation, fibrosis, hepatocarcinogenesis and regeneration via the induction of its target genes. Inflammation is the most common feature of chronic liver diseases, triggering fibrosis, cirrhosis and hepatocellular carcinoma. Increasing evidence indicates that Nrf2 counteracts the proinflammatory process by modulating the recruitment of inflammatory cells and inducing the endogenous antioxidant response of the cell. In this review, the interactions between antioxidant and inflammatory molecular pathways are analyzed.

Curcumin and α/β-Adrenergic Antagonists Cotreatment Reverse Liver Cirrhosis in Hamsters: Participation of Nrf-2 and NF-κB

Liver cirrhosis is the result of an uncontrolled fibrogenetic process, due to the activation and subsequent differentiation into myofibroblasts of the hepatic stellate cells (HSC). It is known that HSC express adrenoreceptors (AR), and the use of AR antagonists protects experimental animals from cirrhosis. However, several studies suggest that the toxicity generated by metabolism of these antagonists would hinder its use in cirrhotic patients. In addition, liver fibrosis may be associated with a decrease of the antioxidant response of the nuclear factor erythroid 2-related factor 2 (Nrf-2) and the overregulation of the proinflammatory pathway of nuclear factor kappa B (NF-κB). Therefore, in the present work, the capacity of doxazosin (α1 antagonist), carvedilol (nonselective beta-adrenoceptor blocker with alpha 1-blocking properties), and curcumin (antioxidant and anti-inflammatory compound) to reverse liver cirrhosis and studying the possible modulation of Nrf-2 and NF-κB were evaluated. Hamsters received CCl4 for 20 weeks, and then treatments were immediately administered for 4 weeks more. The individual administration of doxazosin or carvedilol showed less ability to reverse cirrhosis in relation to concomitantly curcumin administration. However, the best effect was the combined effect of doxazosin, carvedilol, and curcumin, reversing liver fibrosis and decreasing the amount of collagen I (Sirius red stain) without affecting the morphology of hepatocytes (hematoxylin and eosin stain), showing normal hepatic function (glucose, albumin, AST, ALT, total bilirubin, and total proteins). In addition, carvedilol treatment and the combination of doxazosin with curcumin increased Nrf-2/NF-κB mRNA ratio and its protein expression in the inflammatory cells in the livers, possibly as another mechanism of hepatoprotection. Therefore, these results suggest for the first time that α/β adrenergic blockers with curcumin completely reverse hepatic damage, possibly as a result of adrenergic antagonism on HSC and conceivably by the increase of Nrf-2/NF-κB mRNA ratio.

Curcumin Provides Hepatoprotection against Amoebic Liver Abscess Induced by Entamoeba histolytica in Hamster: Involvement of Nrf2/HO-1 and NF-κB/IL-1β Signaling Pathways

Amoebic liver abscess (ALA) is the most common extraintestinal amoebiasis caused by Entamoeba histolytica (E. histolytica). However, despite current knowledge and scientific advances about this infection, there are no effective treatments to prevent it. Herein, the antiamoebic capacity of curcumin in a hamster model was evaluated. Curcumin (150 mg/kg, p.o., daily during 10 days before infection) considerably prevents liver damage induced at 12 and 48 h post-intrahepatic inoculation of trophozoites and decreases ALT, ALP, and γ-GTP activities, and macroscopic and microscopic observations were consistent with these results. On the other hand, after one week of intraportal inoculation, liver damage was prevented by curcumin (150 mg/kg, p.o., daily, 20 days before amoebic inoculation and during the week of infection); liver/body weight ratios and tissue and histological stains showed normal appearance; in addition, the increases in ALT, ALP, and γ-GTP activities were prevented; the depletion of glycogen content induced by the amoebic damage was partially but significantly prevented, while NF-κB activity was inhibited and the expression of IL-1β was reduced; Nrf2 production showed a tendency to increase it, and HO-1 protein was overexpressed. These results suggest for the first time that curcumin can be a compound with antiamoebic effect in the liver, suggesting that its daily use could help greatly decrease the incidence of this type of infection.

Liposomal Curcumin is Better than Curcumin to Alleviate Complications in Experimental Diabetic Mellitus

Curcumin (CC) is known to have anti-inflammatory and anti-oxidative properties and has already been tested for its efficiency in different diseases including diabetes mellitus (DM). New formulations and route administration were designed to obtain products with higher bioavailability. Our study aimed to test the effect of intraperitoneal (i.p.) administration of liposomal curcumin (lCC) as pre-treatment in streptozotocin(STZ)-induced DM in rats on oxidative stress, liver, and pancreatic functional parameters. Forty-two Wistar-Bratislava rats were randomly divided into six groups (seven animals/group): control (no diabetes), control-STZ (STZ-induced DM —60 mg/100g body weight a single dose intraperitoneal administration, and no CC pre-treatment), two groups with DM and CC pre-treatment (1mg/100g bw—STZ + CC1, 2 mg/100g bw—STZ + CC2), and two groups with DM and lCC pre-treatment (1 mg/100g bw—STZ + lCC1, 2 mg/100g bw—STZ + lCC1). Intraperitoneal administration of Curcumin in diabetic rats showed a significant reduction of nitric oxide, malondialdehyde, total oxidative stress, and catalase for both evaluated formulations (CC and lCC) compared to control group (p < 0.005), with higher efficacy of lCC formulation compared to CC solution (p < 0.002, excepting catalase for STZ + CC2vs. STZ + lCC1when p = 0.0845). The CC and lCC showed hepatoprotective and hypoglycemic effects, a decrease in oxidative stress and improvement in anti-oxidative capacity status against STZ-induced DM in rats (p < 0.002). The lCC also proved better efficacy on MMP-2, and -9 plasma levels as compared to CC (p < 0.003, excepting STZ + CC2 vs. STZ + lCC1 comparison with p = 0.0553). The lCC demonstrated significantly better efficacy as compared to curcumin solution on all serum levels of the investigated markers, sustaining its possible use as adjuvant therapy in DM.

Standardized extract of Zingiber zerumbet suppresses LPS-induced pro-inflammatory responses through NF-κB, MAPK and PI3K-Akt signaling pathways in U937 macrophages

BACKGROUND

Zingiber zerumbet rhizome has been used as spices and in traditional medicine to heal various immune-inflammatory related ailments. Although the plant was reported to have potent anti-inflammatory and immunosuppressive properties by several studies, the molecular mechanisms underlying the effects have not been well justified.

PURPOSE

The study was carried out to investigate the molecular mechanisms underlying the anti-inflammatory properties of the standardized 80% ethanol extract of Z. zerumbet through its effect on mitogen-activated protein kinase (MyD88)-dependent nuclear factor-kappa B (NF-кB), mitogen activated protein kinase (MAPK) and phosphatidylinositol 3-kinase/Akt (PI3K-Akt) signaling pathways in lipopolysaccharide (LPS)-induced U937 human macrophages.

METHODS

Standardization of the 80% ethanol extract of Z. zerumbet was performed by using a validated reversed-phase HPLC method, while LC-MS/MS was used to profile the secondary metabolites. The release of pro-inflammatory markers, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and prostaglandin E₂ (PGE₂) was evaluated by enzyme-linked immunosorbent assay (ELISA), while the Western blot technique was executed to elucidate the expression of mediators linked to MyD88-dependent respective signaling pathways. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay was carried out to quantify the relative gene expression of cyclooxygenase (COX)-2 and pro-inflammatory mediators at the transcriptional level.

RESULTS

The quantitative and qualitative analyses of Z. zerumbet extract showed the presence of several compounds including the major chemical marker zerumbone. Z. zerumbet extract suppressed the release of pro-inflammatory mediators, COX-2 protein expression and downregulated the mRNA expression of pro-inflammatory markers. Z. zerumbet-treatment also blocked NF-κB activation by preventing the phosphorylation of IKKα/β and NF-κB (p65) as well as the phosphorylation and degradation of IκBα. Z. zerumbet extract concentration-dependently inhibited the phosphorylation of respective MAPKs (JNK, ERK, and p38) as well as Akt. Correspondingly, Z. zerumbet extract suppressed the upstream signaling adaptor molecules, TLR4 and MyD88 prerequisite for the NF-κB, MAPKs, and PI3K-Akt activation.

CONCLUSION

The findings suggest that Z. zerumbet has impressive role in suppressing inflammation and related immune disorders by inhibition of various pro-inflammatory markers through the imperative MyD88-dependent NF-κB, MAPKs, and PI3K-Akt activation.

Antifibrotic effects of Fraxetin on carbon tetrachloride-induced liver fibrosis by targeting NF-κB/IκBα, MAPKs and Bcl-2/Bax pathways

BACKGROUND

Liver fibrosis is a chronic lesion which ultimately results in cirrhosis and possible death. Although the high incidence and lethality, few therapies are effective for liver fibrosis. Fraxetin (7,8-dihydroxy-6-methoxy coumarin), a natural product extracted from cortex fraxini, has exhibited a significant hepatoprotective and anti-fibrotic properties. However, the underlying mechanism of the anti-hepatic fibrotic property remains unknown.

METHODS

48 Male Sprague Dawley rats were divided into four groups at random which were named as normal group, model group, fraxetin 25 mg/kg and 50 mg/kg group. The experimental model of liver fibrosis was founded by carbon tetrachloride (CCl₄) rats which were simultaneously treated with fraxetin (25 mg/kg or 50 mg/kg). Normal groups received equal volumes of saline and peanut oil.

RESULTS

Results showed that fraxetin ameliorated CCl₄ induced liver damage and fibrosis. Furthermore, histopathology examinations revealed that fraxetin improved the morphology and alleviated collagen deposition in fibrotic liver. Fraxetin inhibited inflammation and hepatocytes apoptosis by modulating the NF-κB/IκBα, MAPKs and Bcl-2/Bax signaling pathways.

CONCLUSION

Our findings indicate that fraxetin is effective in preventing liver fibrosis through inhibiting inflammation and hepatocytes apoptosis which is associated with regulating NF-κB/IκBα, MAPKs and Bcl-2/Bax signaling pathways in rats.

Radiation-Induced Reactions in The Liver - Modulation of Radiation Effects by Lifestyle-Related Factors

Radiation has a wide variety of effects on the liver. Fibrosis is a concern in medical fields as one of the acute effects of high-dose irradiation, such as with cancer radiotherapies. Cancer is also an important concern following exposure to radiation. The liver has an active metabolism and reacts to radiations. In addition, effects are modulated by many environmental factors, such as high-calorie foods or alcohol beverages. Adaptations to other environmental conditions could also influence the effects of radiation. Reactions to radiation may not be optimally regulated under conditions modulated by the environment, possibly leading to dysregulation, disease or cancer. Here, we introduce some reactions to ionizing radiation in the liver, as demonstrated primarily in animal experiments. In addition, modulation of radiation-induced effects in the liver due to factors such as obesity, alcohol drinking, or supplements derived from foods are reviewed. Perspectives on medical applications by modulations of radiation effects are also discussed.

Hepatoprotective effect of rhein against methotrexate-induced liver toxicity

The purpose of this study was to investigate the protective effect of rhein, a major metabolite of diacerein, on methotrexate (MTX)-induced hepatotoxicity and clarify the pharmacological mechanism. Rhein significantly reduced the elevation of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) caused by MTX in rat serum and improved liver morphological damage induced by MTX. Moreover, rhein increased the cell survival rate and reduced the number of apoptosis cells in MTX-treated normal human hepatocyte (L02 cells). Rhein treatment in rats up-regulated nuclear factor erythroid 2-related factor 2 (Nrf2), B-cell lymphoma-2 (Bcl-2), heme oxygenase 1 (HO-1) and glutamate-cysteine ligase catalytic subunit (GCLC), and down-regulated Bcl-2 associated x (Bax) in mRNA and protein levels. Furthermore, rhein treatment further decreased protein expression of nuclear factor-kappa B (NF-κB), tumor necrosis factor alpha (TNF-α) and cysteine aspartic acid specific protease 3 (Caspase-3), increased protein expression of B-cell lymphoma-extra large (Bcl-xl), and reduced mRNA expression of Bcl-2 homologous antagonist/killer (Bak) in MTX-treated rat liver in vivo. However, the protein expression changes of Nrf2, HO-1, GCLC, Bcl-2, Bcl-xl and Bax could be abrogated by Nrf2 antagonist brusatol. In addition, protective effect of rhein against MTX-mediated liver damage could also be suppressed by Nrf2 siRNA in L02 cells. Taken together, these findings suggested that rhein ameliorated liver damage mediated by MTX through acting on Nrf2-HO-1 pathway. NF-κB, TNF-α, Caspase-3 and Bcl-2 family were also participated in the protection. As effectively hepatoprotective ability of rhein, it would raise an important issue for patients orally receiving MTX treatment together with diacerein/rhein.