Alcohol Activates TGF-Beta but Inhibits BMP Receptor-Mediated Smad Signaling and Smad4 Binding to Hepcidin Promoter in the Liver

Effects of aflatoxin and fumonisin on gene expression of growth factors and inflammation-related genes in a human hepatocyte cell line

Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are mycotoxins widely distributed in maize and maized-based products, often occurring together. The implications of co-exposure to aflatoxin and fumonsin for human health are numerous, but a particular concern is the potential of FB1 to modulate AFB1 hepatotoxicity. This study evaluated the toxicity of these mycotoxins, alone or combined, in a human non-tumorigenic liver cell line, HHL-16 cells, and assessed the effects of AFB1 and FB1 on expression of genes involved in immune and growth factor pathways. The results demonstrated that in HHL-16 cells, both AFB1 and FB1 had dose-dependent and time-dependent toxicity, and the combination of them showed a synergistic toxicity in the cells. Moreover, AFB1 caused upregulation of IL6, CCL20, and BMP2, and downregulation of NDP. In combination of AFB1 with FB1, gene expression levels of IL6 and BMP2 were significantly higher compared to individual FB1 treatment, and had a tendency to be higher than individual AFB1 treatment. This study shows that FB1 may increase the hepatoxicity of AFB1 through increasing the inflammatory response and disrupting cell growth pathways.

Mutation in the Bone Morphogenetic Protein signaling pathway sensitize zebrafish and humans to ethanol-induced jaw malformations

Fetal Alcohol Spectrum Disorders (FASD) describe ethanol-induced developmental defects including craniofacial malformations. While ethanol-sensitive genetic mutations contribute to facial malformations, the impacted cellular mechanisms remain unknown. Bmp signaling is a key regulator of epithelial morphogenesis driving facial development, providing a possible ethanol-sensitive mechanism. We found that zebrafish mutants for Bmp signaling components are ethanol-sensitive and affect anterior pharyngeal endoderm shape and gene expression, indicating ethanol-induced malformations of the anterior pharyngeal endoderm cause facial malformations. Integrating FASD patient data, we provide the first evidence that variants in the human Bmp receptor gene BMPR1B associate with ethanol-related differences in jaw volume. Our results show that ethanol exposure disrupts proper morphogenesis of, and tissue interactions between, facial epithelia that mirror overall viscerocranial shape changes and are predictive for Bmp-ethanol associations in human jaw development. Our data provide a mechanistic paradigm linking ethanol to disrupted epithelial cell behaviors that underlie facial defects in FASD.

Liver Iron Loading in Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) is a common chronic liver disease with increasing incidence worldwide. Alcoholic liver steatosis/steatohepatitis can progress to liver fibrosis/cirrhosis, which can cause predisposition to hepatocellular carcinoma. ALD diagnosis and management are confounded by several challenges. Iron loading is a feature of ALD which can exacerbate alcohol-induced liver injury and promote ALD pathologic progression. Knowledge of the mechanisms that mediate liver iron loading can help identify cellular/molecular targets and thereby aid in designing adjunct diagnostic, prognostic, and therapeutic approaches for ALD. Herein, the cellular mechanisms underlying alcohol-induced liver iron loading are reviewed and how excess iron in patients with ALD can promote liver fibrosis and aggravate disease pathology is discussed. Alcohol-induced increase in hepatic transferrin receptor-1 expression and up-regulation of high iron protein in Kupffer cells (proposed) facilitate iron deposition and retention in the liver. Iron is loaded in both parenchymal and nonparenchymal liver cells. Iron-loaded liver can promote ferroptosis and thereby contribute to ALD pathology. Iron and alcohol can independently elevate oxidative stress. Therefore, a combination of excess iron and alcohol amplifies oxidative stress and accelerates liver injury. Excess iron-stimulated hepatocytes directly or indirectly (through Kupffer cell activation) activate the hepatic stellate cells via secretion of proinflammatory and profibrotic factors. Persistently activated hepatic stellate cells promote liver fibrosis, and thereby facilitate ALD progression.

Iron, glucose and fat metabolism and obesity: an intertwined relationship

A bidirectional relationship exists between adipose tissue metabolism and iron regulation. Total body fat, fat distribution and exercise influence iron status and components of the iron-regulatory pathway, including hepcidin and erythroferrone. Conversely, whole body and tissue iron stores associate with fat mass and distribution and glucose and lipid metabolism in adipose tissue, liver, and muscle. Manipulation of the iron-regulatory proteins erythroferrone and erythropoietin affects glucose and lipid metabolism. Several lines of evidence suggest that iron accumulation and metabolism may play a role in the development of metabolic diseases including obesity, type 2 diabetes, hyperlipidaemia and non-alcoholic fatty liver disease. In this review we summarise the current understanding of the relationship between iron homoeostasis and metabolic disease.

Alcohol-induced increase in BMP levels promotes fatty liver disease in male prediabetic stage Otsuka Long-Evans Tokushima Fatty rats

Alcohol consumption exacerbates liver abnormalities in animal models, but whether it increases the severity of liver disease in early diabetic or prediabetic rats is unclear. To investigate the molecular mechanisms underlying alcohol-induced liver steatosis or hepatitis, we used a prediabetic animal model. Otsuka Long-Evans Tokushima Fatty (OLETF) and Long-Evans Tokushima Fatty (LETO) rats were pair-fed with an ethanol-containing liquid diet for 6 weeks. Compared with controls, OLETF and LETO rats displayed more pronounced liver steatosis and higher plasma levels of serum glutamic oxaloacetic transaminase (SGOT) and serum glutamate pyruvate transaminase (SPGT), indicating liver injury. Ethanol-fed LETO (Pd-L-E) rats showed mild liver steatosis and no inflammation compared with ethanol-fed OLETF (Pd-O-E) rats. Although precursor and active SREBP-1 levels in the liver of ethanol-fed OLETF rats significantly increased compared with control diet-fed OLETF rats (Pd-O-C), those of Pd-L-E rats did not. Bone morphogenetic protein (BMP) and TGF-β1 balance in Pd-O-E rats was significantly altered because BMP signaling was upregulated by inducing BMP2, BMP4, BMP7, BMP9, Smad1, and Smad4, whereas TGF-β1, Smad3, and Erk were downregulated. Activation of TGF-β/Smad signaling inhibited BMP2 and BMP9 expression and increased epithelial-mesenchymal transition (EMT) marker levels (Hepcidin, Snail, and Twist) in the liver of LETO rats. Livers of ethanol-fed OLETF rats showed increased levels of vimentin, FSP-1, α-SMA, MMP1, MMP13, and collagen III compared with rats of other groups, whereas EMT marker levels did not change. Thus, BMP exerted anti- and/or pro-fibrotic effects in ethanol-fed rats. Therefore, BMP and TGF-β, two key members of the TGF-β superfamily, play important but diverse roles in liver steatosis in young LETO and OLETF rats.

Iron as a therapeutic target in chronic liver disease

It was clearly realized more than 50 years ago that iron deposition in the liver may be a critical factor in the development and progression of liver disease. The recent clarification of ferroptosis as a specific form of regulated hepatocyte death different from apoptosis and the description of ferritinophagy as a specific variation of autophagy prompted detailed investigations on the association of iron and the liver. In this review, we will present a brief discussion of iron absorption and handling by the liver with emphasis on the role of liver macrophages and the significance of the iron regulators hepcidin, transferrin, and ferritin in iron homeostasis. The regulation of ferroptosis by endogenous and exogenous mod-ulators will be examined. Furthermore, the involvement of iron and ferroptosis in various liver diseases including alcoholic and non-alcoholic liver disease, chronic hepatitis B and C, liver fibrosis, and hepatocellular carcinoma (HCC) will be analyzed. Finally, experimental and clinical results following interventions to reduce iron deposition and the promising manipulation of ferroptosis will be presented. Most liver diseases will be benefited by ferroptosis inhibition using exogenous inhibitors with the notable exception of HCC, where induction of ferroptosis is the desired effect. Current evidence mostly stems from in vitro and in vivo experimental studies and the need for well-designed future clinical trials is warranted.

Novel insights into alcoholic liver disease: Iron overload, iron sensing and hemolysis

The liver is the major target organ of continued alcohol consumption at risk and resulting alcoholic liver disease (ALD) is the most common liver disease worldwide. The underlying molecular mechanisms are still poorly understood despite decades of scientific effort limiting our abilities to identify those individuals who are at risk to develop the disease, to develop appropriate screening strategies and, in addition, to develop targeted therapeutic approaches. ALD is predestined for the newly evolving translational medicine, as conventional clinical and health care structures seem to be constrained to fully appreciate this disease. This concept paper aims at summarizing the 15 years translational experience at the Center of Alcohol Research in Heidelberg, namely based on the long-term prospective and detailed characterization of heavy drinkers with mortality data. In addition, novel experimental findings will be presented. A special focus will be the long-known hepatic iron accumulation, the somewhat overlooked role of the hematopoietic system and novel insights into iron sensing and the role of hepcidin. Our preliminary work indicates that enhanced red blood cell (RBC) turnover is critical for survival in ALD patients. RBC turnover is not primarily due to vitamin deficiency but rather to ethanol toxicity directly targeted to erythrocytes but also to the bone marrow stem cell compartment. These novel insights also help to explain long-known aspects of ALD such as mean corpuscular volume of erythrocytes (MCV) and elevated aspartate transaminase (GOT/AST) levels. This work also aims at identifying future projects, naming unresolved observations, and presenting novel hypothetical concepts still requiring future validation.

Myricetin reduces cytotoxicity by suppressing hepcidin expression in MES23.5 cells

Multiple studies implicate iron accumulation in the substantia nigra in the degeneration of dopaminergic neurons in Parkinson’s disease. Indeed, slowing of iron accumulation in cells has been identified as the key point for delaying and treating Parkinson’s disease. Myricetin reportedly plays an important role in anti-oxidation, anti-apoptosis, anti-inflammation, and iron chelation. However, the mechanism underlying its neuroprotection remains unclear. In the present study, MES23.5 cells were treated with 1 × 10^–6 M myricetin for 1 hour, followed by co-treatment with 400 nM rotenone for 24 hours to establish an in vitro cell model of Parkinson’s disease. Our results revealed that myricetin alleviated rotenone-induced decreases in cell viability, suppressed the production of intracellular reactive oxygen species, and restored mitochondrial transmembrane potential. In addition, myricetin significantly suppressed rotenone-induced hepcidin gene transcription and partly relieved rotenone-induced inhibition of ferroportin 1 mRNA and protein levels. Furthermore, myricetin inhibited rotenone-induced phosphorylation of STAT3 and SMAD1 in MES23.5 cells. These findings suggest that myricetin protected rotenone-treated MES23.5 cells by potently inhibiting hepcidin expression to prevent iron accumulation, and this effect was mediated by alteration of STAT3 and SMAD1 signaling pathways.

Candidate rejuvenating factor GDF11 and tissue fibrosis: friend or foe?

Growth differentiation factor 11 (GDF11 or bone morphogenetic protein 11, BMP11) belongs to the transforming growth factor-β superfamily and is closely related to other family member-myostatin (also known as GDF8). GDF11 was firstly identified in 2004 due to its ability to rejuvenate the function of multiple organs in old mice. However, in the past few years, the heralded rejuvenating effects of GDF11 have been seriously questioned by many studies that do not support the idea that restoring levels of GDF11 in aging improves overall organ structure and function. Moreover, with increasing controversies, several other studies described the involvement of GDF11 in fibrotic processes in various organ setups. This review paper focuses on the GDF11 and its pro- or anti-fibrotic actions in major organs and tissues, with the goal to summarize our knowledge on its emerging role in regulating the progression of fibrosis in different pathological conditions, and to guide upcoming research efforts.

Alcohol induces programmed death receptor-1 and programmed death-ligand-1 differentially in neuroimmune cells

Engagement of programmed death-1 (PD-1) receptor by its ligands (PD-L1/PD-L2) in activated immune cells is known to be involved in inflammatory neurological disease via a co-inhibitory signal pathway. Interaction of PD-1/PD-L1 is believed to occur only in activated neuroimmune cells because there are undetectable levels of PD-1/PD-L1 in normal physiological conditions. Here, we evaluated whether activation of neuroimmune cells such as human macrophage, brain endothelial cells (hBECs), astrocytes, microglia, and neurons by non-toxic concentrations of ethanol (EtOH) exposure can alter PD-1/PD-L1 expression. Thus, the present study is limited to the screening of PD-1/PD-L1 alterations in neuroimmune cells following ethanol exposure. We found that exposure of human macrophage or microglia to EtOH in primary culture immediately increased the levels of PD-L1 and gradually up-regulated PD-1 levels (beginning at 1-2 h). Similarly, ethanol exposure was able to induce PD-1/PD-L1 levels in hBECs and neuronal culture in a delayed process (occurring at 24 h). Astrocyte culture was the only cell type that showed endogenous levels of PD-1/PD-L1 that was decreased by EtOH exposure time-dependently. We concluded that ethanol (alcohol) mediated the induction of PD-1/PD-L1 differentially in neuroimmune cells. Taken together, our findings suggest that up-regulation of PD-1/PD-L1 by chronic alcohol use may dampen the innate immune response of neuroimmune cells, thereby contributing to neuroinflammation and neurodegeneration.

Benzyl alcohol accelerates recovery from Achilles tendon injury, potentially via TGF-β1/Smad2/3 pathway

Benzyl alcohol (BnOH) is a natural colorless liquid organic compound that plays an important role in bacteriostatic and anesthetic processes. It is also used to relieve the nerve and ganglionic pain. In this study, we assessed the effect of topical application of BnOH on the Achilles tendon healing process. Sprague Dawley rats were subjected to an experimentally induced wound in the tendon area and then randomized into four groups. Normal saline (0.5 mL) was applied to rats in control group, and BnOH at the concentrations of 0.5 mL 0.075%, 0.15%, 0.3% were applied to the BnOH treatment groups, respectively. Wound treatment with BnOH led to significantly faster functional recovery than with saline. Moreover, treatment of wounds with 0.3% BnOH accelerated the healing process faster than with 0.075% and 0.15% BnOH. Histological analysis of healed wounds that had been treated with BnOH showed more collagen and blood capillaries and fewer inflammatory cells compared to the control. To study the mechanism of the process, the expression of mRNA of TGF-β1, Smad2/3 and Smad7 and protein of TGF-β1, p-Smad2/3 and Smad7 were quantified by real-time PCR and Western blotting, respectively. Results of this study showed that wounds treated with BnOH significantly enhanced the expression of TGF-β1 and Smad2/3 and reduced the expression of Smad7. In general, the current study demonstrated that BnOH improved the recovery process of tendon healing through the promotion of collagen with angiogenesis and showed that TGF-β plays a role in BnOH treatment of tendon healing.

Induction of Steatohepatitis and Liver Tumorigenesis by Enforced Snail Expression in Hepatocytes

Snail is a transcription factor that regulates many cellular events involved in development, homeostasis, and disease. In hepatocellular carcinoma (HCC), Snail induces epithelial-to-mesenchymal transition that confers invasive properties on tumor cells during HCC progression and malignancy. Snail activation observed in HCC mouse models suggests its involvement not only in progression, but also onset of HCC. However, it remains unclear whether Snail directly contributes to HCC initiation or whether it supports HCC initiation promoted by other oncogenes. In this study, we generated mouse models for liver-specific and hepatocyte-specific overexpression of Snail to show the independent roles of Snail in liver homeostasis and disease. Enforced Snail expression resulted in liver and hepatocyte enlargement, inflammatory cell infiltration in the liver, lipid accumulation in hepatocytes, substantial increases in serum alanine aminotransferase and bile acids, yellow discoloration of tissues caused by bilirubin accumulation, and liver tumorigenesis. Snail overexpression suppressed mRNA expression of the tight junction components claudins and occludin and that of proteins associated with bile acid metabolism, leading to disruption of the biliary canaliculus formed among hepatocytes and excretion of abnormal amounts of unusual bile acids from hepatocytes. In conclusion, enforced Snail expression in hepatocytes is sufficient for induction of steatohepatitis and liver tumorigenesis through disruption of the biliary canaliculus and bile acid homeostasis in the liver.

Computational and biological investigation of the soybean lecithin-gallic acid complex for ameliorating alcoholic liver disease in mice with iron overload

Alcoholic liver disease (ALD) is associated with significant morbidity and mortality globally. In this study, the soybean lecithin-gallic acid complex was synthesized, and its physicochemical properties were evaluated, which confirmed the complex formation. Compared with the free state of the drug, gallic acid exhibited significantly different physicochemical properties after it was complexed with soybean lecithin. To clarify the binding mode between two monomers, computational investigation was performed. From the computational data, we deduced the structure of the compound and predicted that it has a high affinity for human phosphatidylcholine transfer protein and exhibits strong pharmacological activities in vivo. The complex not only effectively ameliorated liver fibrosis, lipid peroxidation, and oxidative stress, but also reduced liver iron overload in a mouse ALD model induced by alcohol (p < 0.05). Additionally, it regulated iron metabolism by inhibiting TfR1 expression (p < 0.05) and promoting hepcidin expression (p < 0.05). These results suggest that the soybean lecithin-gallic acid complex ameliorates hepatic damage and iron overload induced by alcohol and exert hepatoprotective effects.

p53-Mediated Activities in NS-5 Neural Stem Cells: Effects of Ethanol

BACKGROUND

Transforming growth factor (TGF) β1 and ethanol (EtOH) powerfully inhibit the proliferation, DNA repair, and survival of neural stem cells (NSCs). The present study tests the hypothesis that the EtOH-induced DNA damage response is mediated through p53 pathways and influenced by growth factor signals.

METHODS

Cultures of nonimmortalized NSCs, NS-5 cells, were transfected with p53 siRNA, exposed to either the mitogenic fibroblast growth factor (FGF) 2 or antimitogenic TGFβ1, and to EtOH. Stage-specific cellular and genomic responses were examined.

RESULTS

p53 status, EtOH exposure, and growth factor significantly affected the expression of transcripts related to the DNA damage response (including those coding for excision repair proteins), mitotic promoters, and regulators of cell death via the tumor necrosis factor pathway. There were significant compensatory increases in p53 family members, p63 and p73, notably in regard to the regulation of cell cycle restriction and apoptosis. Treatment with p53 siRNA potentiated EtOH- and TGFβ1-induced changes in the numbers of proliferating NSCs and increased the proportion of NSCs expressing the apoptotic marker annexin V.

CONCLUSIONS

Thus, it appears that EtOH and TGFβ1 affect proliferation, DNA repair, and survival of NSCs via p53-mediated activities.

Iron and liver fibrosis: Mechanistic and clinical aspects

Liver fibrosis is characterised by excessive deposition of extracellular matrix that interrupts normal liver functionality. It is a pathological stage in several untreated chronic liver diseases such as the iron overload syndrome hereditary haemochromatosis, viral hepatitis, alcoholic liver disease, non-alcoholic fatty liver disease, non-alcoholic steatohepatitis and diabetes. Interestingly, regardless of the aetiology, iron-loading is frequently observed in chronic liver diseases. Excess iron can feed the Fenton reaction to generate unquenchable amounts of free radicals that cause grave cellular and tissue damage and thereby contribute to fibrosis. Moreover, excess iron can induce fibrosis-promoting signals in the parenchymal and non-parenchymal cells, which accelerate disease progression and exacerbate liver pathology. Fibrosis regression is achievable following treatment, but if untreated or unsuccessful, it can progress to the irreversible cirrhotic stage leading to organ failure and hepatocellular carcinoma, where resection or transplantation remain the only curative options. Therefore, understanding the role of iron in liver fibrosis is extremely essential as it can help in formulating iron-related diagnostic, prognostic and treatment strategies. These can be implemented in isolation or in combination with the current approaches to prepone detection, and halt or decelerate fibrosis progression before it reaches the irreparable stage. Thus, this review narrates the role of iron in liver fibrosis. It examines the underlying mechanisms by which excess iron can facilitate fibrotic responses. It describes the role of iron in various clinical pathologies and lastly, highlights the significance and potential of iron-related proteins in the diagnosis and therapeutics of liver fibrosis.

Effects of Episodic Alcohol Exposure on BMP2 Signaling During Tibia Fracture Healing

OBJECTIVES

To explore how alcohol affects the BMP-2 signaling pathway, which is known to play a critical role in bone and cartilage formation during fracture healing.

METHODS

A rat model was used to demonstrate the detrimental effects of alcohol exposure on tibia fracture healing. Specific components of the BMP-2 pathway were analyzed in fracture callus on days 3, 7, 14, and 21 after fracture via western immunoassays and enzyme-linked immunosorbent assay.

RESULTS

Alcohol exposure before tibia fracture demonstrated attenuation of downstream BMP-2 signaling. The BMP-2 antagonist, Chordin, may be the central component of the BMP-2-related changes demonstrated in this study. Although alcohol affected BMP-related proteins at all time points, it seems that day 14 after fracture is a critical time point for alcohol-related modulation of callus formation in our model.

CONCLUSIONS

This study may provide the scientific basis for further studies addressing whether the application of exogenous BMP-2 in patients with a history of alcohol abuse who sustain long bone fractures may or may not be of benefit.

Low hepcidin in liver fibrosis and cirrhosis; a tale of progressive disorder and a case for a new biochemical marker

Liver fibrosis is a precursor of liver cirrhosis, which is associated with increased mortality. Though liver biopsy remains the gold standard for the diagnosis of fibrosis, noninvasive biochemical methods are cost-effective, practical and are not linked with major risks of complications. In this respect, serum hepcidin, has emerged as a new marker of fibrosis and cirrhosis. In this review the discussion uncovers molecular links between hepcidin disturbance and liver fibrosis/cirrhosis. The discussion also expands on clinical studies that suggest that hepcidin can potentially be used as a biochemical parameter of fibrosis/cirrhosis and target of therapeutic strategies to treat liver diseases. The debatable issues such as the complicated nature of hepcidin disturbance in non-alcoholic liver disease, serum levels of hepcidin in acute hepatitis C virus infection, cause of hepcidin disturbance in autoimmune hepatitis and hepatic insulin resistance are discussed, with potential solutions unveiled in order to be studied by future research.

BMP Signalling at the Crossroad of Liver Fibrosis and Regeneration

Bone Morphogenetic Proteins (BMPs) belong to the Transforming Growth Factor-β (TGF-β) family. Initially identified due to their ability to induce bone formation, they are now known to have multiple functions in a variety of tissues, being critical not only during development for tissue morphogenesis and organogenesis but also during adult tissue homeostasis. This review focus on the liver as a target tissue for BMPs actions, devoting most efforts to summarize our knowledge on their recently recognized and/or emerging roles on regulation of the liver regenerative response to various insults, either acute or chronic and their effects on development and progression of liver fibrosis in different pathological conditions. In an attempt to provide the basis for guiding research efforts in this field both the more solid and more controversial areas of research were highlighted.

Does Hypoxia Cause Carcinogenic Iron Accumulation in Alcoholic Liver Disease (ALD)?

Alcoholic liver disease (ALD) is a leading health risk worldwide. Hepatic iron overload is frequently observed in ALD patients and it is an important and independent factor for disease progression, survival, and the development of primary liver cancer (HCC). At a systemic level, iron homeostasis is controlled by the liver-secreted hormone hepcidin. Hepcidin regulation is complex and still not completely understood. It is modulated by many pathophysiological conditions associated with ALD, such as inflammation, anemia, oxidative stress/H₂O_2, or hypoxia. Namely, the data on hypoxia-signaling of hepcidin are conflicting, which seems to be mainly due to interpretational limitations of in vivo data and methodological challenges. Hence, it is often overlooked that hepcidin-secreting hepatocytes are physiologically exposed to 2–7% oxygen, and that key oxygen species such as H₂O₂ act as signaling messengers in such a hypoxic environment. Indeed, with the recently introduced glucose oxidase/catalase (GOX/CAT) system it has been possible to independently study hypoxia and H₂O₂ signaling. First preliminary data indicate that hypoxia enhances H₂O₂-mediated induction of hepcidin, pointing towards oxidases such as NADPH oxidase 4 (NOX4). We here review and discuss novel concepts of hypoxia signaling that could help to better understand hepcidin-associated iron overload in ALD.

Berberine Preconditioning Protects Neurons Against Ischemia via Sphingosine-1-Phosphate and Hypoxia-Inducible Factor-1α

Berberine exerts neuroprotective and modulates hypoxia inducible factor-1-alpha (HIF-1[Formula: see text]. Based on the role of HIF-1[Formula: see text] in hypoxia preconditioning and association between HIF-1[Formula: see text] and sphingosine-1-phosphate (S1P), we hypothesized that berberine preconditioning (BP) would ameliorate the cerebral injury induced by ischemia through activating the system of HIF-1[Formula: see text] and S1P. Adult male rats with middle cerebral artery occlusion (MCAO) and rat primary cortical neurons treated with oxygen and glucose deprivation (OGD) with BP at 24[Formula: see text]h (40[Formula: see text]mg/kg) and 2[Formula: see text]h (10[Formula: see text][Formula: see text]mol/L), respectively, were used to determine the neuroprotective effects. The HIF-1[Formula: see text] accumulation, and S1P metabolism were assayed in the berberine-preconditioned neurons, and the HIF-1[Formula: see text]-mediated transcriptional modulation of sphingosine kinases (Sphk) 1 and 2 was analyzed using chromatin immunoprecipitation and real-time polymerase chain reaction. BP significantly prevented cerebral ischemic injury in the MCAO rats at 24[Formula: see text]h and 72[Formula: see text]h following ischemia/reperfusion. In OGD-treated neurons, BP enhanced HIF-1[Formula: see text] accumulation with activation of PI3K/Akt, and induced S1P production by activating Sphk2 via the promotion of HIF-1[Formula: see text]-mediated Sphk2 transcription. In conclusion, BP activated endogenous neuroprotective mechanisms associated with the S1P/HIF-1 pathway and helped protect neuronal cells against hypoxia/ischemia.

The rationale for targeting TGF-β in chronic liver diseases

BACKGROUND

Transforming growth factor (TGF)-β is a pluripotent cytokine that displays several tissue-specific biological activities. In the liver, TGF-β is considered a fundamental molecule, controlling organ size and growth by limiting hepatocyte proliferation. It is involved in fibrogenesis and, therefore, in worsening liver damage, as well as in triggering the development of hepatocellular carcinoma (HCC). TGF-β is known to act as an oncosuppressor and also as a tumour promoter in HCC, but its role is still unclear.

DESIGN

In this review, we discuss the potential role of TGF-β in regulating the tumoural progression of HCC, and therefore the rationale for targeting this molecule in patients with HCC.

RESULTS

A considerable amount of experimental preclinical evidence suggests that TGF-β is a promising druggable target in patients with HCC. To support this hypothesis, a phase II clinical trial is currently ongoing using a TGF-β pathway inhibitor, and results will soon be available.

CONCLUSIONS

The identification of new TGF-β related biomarkers will help to select those patients most likely to benefit from therapy aimed at inhibiting the TGF-β pathway. New formulations that may provide a more controlled and sustained delivery of the drug will improve the therapeutic success of such treatments.

Neonatal binge alcohol exposure increases microglial activation in the developing rat hippocampus

Aberrant activation of the developing immune system can have long-term negative consequences on cognition and behavior. Teratogens, such as alcohol, activate microglia, the brain's resident immune cells, which could contribute to the lifelong deficits in learning and memory observed in humans with Fetal Alcohol Spectrum Disorders (FASD) and in rodent models of FASD. The current study investigates the microglial response of the brain 24 h following neonatal alcohol exposure (postnatal days (PDs) 4-9, 5.25 g/kg/day). On PD10, microglial cell counts and area of cell territory were assessed using unbiased stereology in the hippocampal subfields CA1, CA3 and dentate gyrus (DG), and hippocampal expression of pro- and anti-inflammatory genes was analyzed. A significant decrease in microglial cell counts in CA1 and DG was found in alcohol-exposed and sham-intubated (SI) animals compared to undisturbed suckle controls (SCs), suggesting overlapping effects of alcohol exposure and intubation alone on the neuroimmune response. Cell territory was decreased in alcohol-exposed animals in CA1, CA3, and DG compared to controls, suggesting the microglia have shifted to a more activated state following alcohol treatment. Furthermore, both alcohol-exposed and SI animals had increased levels of pro-inflammatory cytokines IL-1β, TNF-α, CD11b, and CCL4; in addition, CCL4 was significantly increased in alcohol-exposed animals compared to SI as well. Alcohol-exposed animals also showed increased levels of anti-inflammatory cytokine TGF-β compared to both SI and SCs. In summary, the number and activation of microglia in the neonatal hippocampus are both affected in a rat model of FASD, along with increased gene expression of pro- and anti-inflammatory cytokines. This study shows that alcohol exposure during development induces a neuroimmune response, potentially contributing to long-term alcohol-related changes to cognition, behavior and immune function.

Ceramide Induces Human Hepcidin Gene Transcription through JAK/STAT3 Pathway

Changes in lipid metabolism and iron content are observed in the livers of patients with fatty liver disease. The expression of hepcidin, an iron-regulatory and acute phase protein synthesized by the liver, is also modulated. The potential interaction of lipid and iron metabolism is largely unknown. We investigated the role of lipid intermediate, ceramide in the regulation of human hepcidin gene, HAMP. Human hepatoma HepG2 cells were treated with cell-permeable ceramide analogs. Ceramide induced significant up-regulation of HAMP mRNA expression in HepG2 cells. The effect of ceramide on HAMP expression was mediated through transcriptional mechanisms because it was completely blocked with actinomycin D treatment. Reporter assays also confirmed the activation of 0.6 kb HAMP promoter by ceramide. HepG2 cells treated with ceramide displayed increased phosphorylation of STAT3, JNK, and NF-κB proteins. However, ceramide induced the binding of STAT3, but not NF-κB or c-Jun, to HAMP promoter, as shown by the chromatin immunoprecipitation assays. The mutation of STAT3 response element within 0.6 kb HAMP promoter region significantly inhibited the stimulatory effect of ceramide on HAMP promoter activity. Similarly, the inhibition of STAT3 with a pan-JAK kinase inhibitor and STAT3 siRNA pool also diminished the induction of both HAMP promoter activity and mRNA expression by ceramide. In conclusion, we have shown a direct role for ceramide in the activation of hepatic HAMP transcription via STAT3. Our findings suggest a crosstalk between lipid and iron metabolism in the liver, which may contribute to the pathogenesis of obesity-related fatty liver disease.

Metabolic derivatives of alcohol and the molecular culprits of fibro-hepatocarcinogenesis: Allies or enemies?

Chronic intake of alcohol undoubtedly overwhelms the structural and functional capacity of the liver by initiating complex pathological events characterized by steatosis, steatohepatitis, hepatic fibrosis and cirrhosis. Subsequently, these initial pathological events are sustained and ushered into a more complex and progressive liver disease, increasing the risk of fibro-hepatocarcinogenesis. These coordinated pathological events mainly result from buildup of toxic metabolic derivatives of alcohol including but not limited to acetaldehyde (AA), malondialdehyde (MDA), CYP2E1-generated reactive oxygen species, alcohol-induced gut-derived lipopolysaccharide, AA/MDA protein and DNA adducts. The metabolic derivatives of alcohol together with other comorbidity factors, including hepatitis B and C viral infections, dysregulated iron metabolism, abuse of antibiotics, schistosomiasis, toxic drug metabolites, autoimmune disease and other non-specific factors, have been shown to underlie liver diseases. In view of the multiple etiology of liver diseases, attempts to delineate the mechanism by which each etiological factor causes liver disease has always proved cumbersome if not impossible. In the case of alcoholic liver disease (ALD), it is even more cumbersome and complicated as a result of the many toxic metabolic derivatives of alcohol with their varying liver-specific toxicities. In spite of all these hurdles, researchers and experts in hepatology have strived to expand knowledge and scientific discourse, particularly on ALD and its associated complications through the medium of scientific research, reviews and commentaries. Nonetheless, the molecular mechanisms underpinning ALD, particularly those underlying toxic effects of metabolic derivatives of alcohol on parenchymal and non-parenchymal hepatic cells leading to increased risk of alcohol-induced fibro-hepatocarcinogenesis, are still incompletely elucidated. In this review, we examined published scientific findings on how alcohol and its metabolic derivatives mount cellular attack on each hepatic cell and the underlying molecular mechanisms leading to disruption of core hepatic homeostatic functions which probably set the stage for the initiation and progression of ALD to fibro-hepatocarcinogenesis. We also brought to sharp focus, the complex and integrative role of transforming growth factor beta/small mothers against decapentaplegic/plasminogen activator inhibitor-1 and the mitogen activated protein kinase signaling nexus as well as their cross-signaling with toll-like receptor-mediated gut-dependent signaling pathways implicated in ALD and fibro-hepatocarcinogenesis. Looking into the future, it is hoped that these deliberations may stimulate new research directions on this topic and shape not only therapeutic approaches but also models for studying ALD and fibro-hepatocarcinogenesis.

Enhanced expression of BMP6 inhibits hepatic fibrosis in non-alcoholic fatty liver disease

OBJECTIVE

Bone morphogenetic protein 6 (BMP6) has been identified as crucial regulator of iron homeostasis. However, its further role in liver pathology including non-alcoholic fatty liver disease (NAFLD) and its advanced form non-alcoholic steatohepatitis (NASH) is elusive. The aim of this study was to investigate the expression and function of BMP6 in chronic liver disease.

DESIGN

BMP6 was analysed in hepatic samples from murine models of chronic liver injury and patients with chronic liver diseases. Furthermore, a tissue microarray comprising 110 human liver tissues with different degree of steatosis and inflammation was assessed. BMP6-deficient (BMP6(-/-)) and wild-type mice were compared in two dietary NASH-models, that is, methionine choline-deficient (MCD) and high-fat (HF) diets.

RESULTS

BMP6 was solely upregulated in NAFLD but not in other murine liver injury models or diseased human livers. In NAFLD, BMP6 expression correlated with hepatic steatosis but not with inflammation or hepatocellular damage. Also, in vitro cellular lipid accumulation in primary human hepatocytes induced increased BMP6 expression. MCD and HF diets caused more hepatic inflammation and fibrosis in BMP6(-/-) compared with wild-type mice. However, only in the MCD and not in the HF diet model BMP6(-/-) mice developed marked hepatic iron overload, suggesting that further mechanisms are responsible for protective BMP6 effect. In vitro analysis revealed that recombinant BMP6 inhibited the activation of hepatic stellate cells (HSCs) and reduced proinflammatory and profibrogenic gene expression in already activated HSCs.

CONCLUSIONS

Steatosis-induced upregulation of BMP6 in NAFLD is hepatoprotective. Induction of BMP6-signalling may be a promising antifibrogenic strategy.

The effect of alcohol and hydrogen peroxide on liver hepcidin gene expression in mice lacking antioxidant enzymes, glutathione peroxidase-1 or catalase

This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1(-/-)) and catalase (catalase(-/-)) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1(-/-) displayed significantly higher hepatic H2O2 levels than catalase(-/-) compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The basal level of liver hepcidin expression was attenuated in gpx-1(-/-) mice. Alcohol increased H2O2 production in catalase(-/-) and wild-type, but not gpx-1(-/-), mice. Hepcidin expression was inhibited in alcohol-fed catalase(-/-) and wild-type mice. In contrast, alcohol elevated hepcidin expression in gpx-1(-/-) mice. Gpx-1(-/-) mice also displayed higher level of basal liver CHOP protein expression than catalase(-/-) mice. Alcohol induced CHOP and to a lesser extent GRP78/BiP expression, but not XBP1 splicing or binding of CREBH to hepcidin gene promoter, in gpx-1(-/-) mice. The up-regulation of hepatic ATF4 mRNA levels, which was observed in gpx-1(-/-) mice, was attenuated by alcohol. In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo. Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH.

Molecular mechanisms of ethanol-associated oro-esophageal squamous cell carcinoma

Alcohol drinking is a major etiological factor of oro-esophageal squamous cell carcinoma (OESCC). Both local and systemic effects of ethanol may promote carcinogenesis, especially among chronic alcoholics. However, molecular mechanisms of ethanol-associated OESCC are still not well understood. In this review, we summarize current understandings and propose three mechanisms of ethanol-associated OESCC: (1) Disturbance of systemic metabolism of nutrients: during ethanol metabolism in the liver, systemic metabolism of retinoids, zinc, iron and methyl groups is altered. These nutrients are known to be associated with the development of OESCC. (2) Disturbance of redox metabolism in squamous epithelial cells: when ethanol is metabolized in oro-esophageal squamous epithelial cells, reactive oxygen species are generated and produce oxidative damage. Meanwhile, ethanol may also disturb fatty-acid metabolism in these cells. (3) Disturbance of signaling pathways in squamous epithelial cells: due to its physico-chemical properties, ethanol changes cell membrane fluidity and shape, and may thus impact multiple signaling pathways. Advanced molecular techniques in genomics, epigenomics, metabolomics and microbiomics will help us elucidate how ethanol promotes OESCC.

Iron and oxygen sensing: a tale of 2 interacting elements?

Iron and oxygen metabolism are intimately linked with one another.

TLR4 signaling and the inhibition of liver hepcidin expression by alcohol

AIM: To understand the role of toll-like receptor 4 (TLR4) signaling in the regulation of iron-regulatory hormone, hepcidin by chronic alcohol consumption.

METHODS: For chronic alcohol intake studies, TLR4 mutant mice on C3H/HeJ background and wildtype counterpart on C3H/HeOuJ background were pair-fed with regular (control) and ethanol-containing Lieber De Carli liquids diets. Gene expression was determined by real-time quantitative PCR. Protein-protein interactions and protein expression were determined by co-immunoprecipitation and western blotting. The occupancy of hepcidin gene promoter was determined by chromatin immunoprecipitation assays.

RESULTS: Chronic alcohol intake suppressed hepcidin mRNA expression in the livers of wildtype, but not TLR4 mutant, mice. The phosphorylation and nuclear translocation of nuclear factor (NF)-κB p65 subunit protein was observed in alcohol-fed wildtype, but not in alcohol-fed TLR4 mutant, mice. Similarly, alcohol induced the binding of NF-κB p50 subunit protein to hepcidin gene promoter in wildtype, but not in TLR4 mutant, mice. In contrast, the phosphorylation of Stat3 in the liver was stronger in alcohol-treated TLR4 mutant mice compared to alcohol-treated wildtype mice. The occupancy of hepcidin gene promoter by Stat3 was observed in alcohol-fed mutant, but not in wildtype, mice. An interaction between NF-κB p65 subunit protein and small heterodimer partner protein (SHP) was observed in the livers of both wildtype and TLR4 mutant mice fed with the control diet, as shown by co-immunoprecipitation studies. Alcohol intake elevated cytosolic SHP expression but attenuated its interaction with NF-κB in the liver, which was more prominent in the livers of wildtype compared to TLR4 mutant mice.

CONCLUSION: Activation of TLR4 signaling and NF-кB are involved in the suppression of hepcidin gene transcription by alcohol in the presence of inflammation in the liver.

Apoptosis induced by Fas signaling does not alter hepatic hepcidin expression

AIM: To determine the regulation of human hepcidin (HAMP) and mouse hepcidin (hepcidin-1 and hepcidin-2) gene expression in the liver by apoptosis using in vivo and in vitro experimental models.

METHODS: For the induction of the extrinsic apoptotic pathway, HepG2 cells were treated with various concentrations of CH11, an activating antibody for human Fas receptor, for 12 h. Male C57BL/6NCR and C57BL/6J strains of mice were injected intraperitoneally with sublethal doses of an activating antibody for mouse Fas receptor, Jo2. The mice were anesthetized and sacrificed 1 or 6 h after the injection. The level of apoptosis was quantified by caspase-3 activity assay. Liver injury was assessed by measuring the levels of ALT/AST enzymes in the serum. The acute phase reaction in the liver was examined by determining the expression levels of IL-6 and SAA3 genes by SYBR green quantitative real-time PCR (qPCR). The phosphorylation of transcription factors, Stat3, Smad4 and NF-κB was determined by western blotting. Hepcidin gene expression was determined by Taqman qPCR. The binding of transcription factors to hepcidin-1 promoter was studied using chromatin immunoprecipitation (ChIP) assays.

RESULTS: The treatment of HepG2 cells with CH11 induced apoptosis, as shown by the significant activation of caspase-3 (P < 0.001), but did not cause any significant changes in HAMP expression. Short-term (1 h) Jo2 treatment (0.2 μg/g b.w.) neither induced apoptosis and acute phase reaction nor altered mRNA expression of mouse hepcidin-1 in the livers of C57BL/6NCR mice. In contrast, 6 h after Jo2 injection, the livers of C57BL/6NCR mice exhibited a significant level of apoptosis (P < 0.001) and an increase in SAA3 (P < 0.023) and IL-6 (P < 0.005) expression in the liver. However, mRNA expression of hepcidin-1 in the liver was not significantly altered. Despite the Jo2-induced phosphorylation of Stat3, no occupancy of hepcidin-1 promoter by Stat3 was observed, as shown by ChIP assays. Compared to C57BL/6NCR mice, Jo2 treatment (0.2 μg/g b.w.) of C57BL/6J strain mice for 6 h induced a more prominent activation of apoptosis, liver injury and acute phase reaction. Similar to C57BL/6NCR mice, the level of liver hepcidin-1 mRNA expression in the livers of C57BL/6J mice injected with a sublethal dose of Jo2 (0.2 μg/g b.w.) remained unchanged. The injection of C57BL/6J mice with a higher dose of Jo2 (0.32 μg/g b.w.) did not also alter hepatic hepcidin expression.

CONCLUSION: Our findings suggest that human or mouse hepcidin gene expression is not regulated by apoptosis induced via Fas receptor activation in the liver.

TGF-β signaling pathway as a pharmacological target in liver diseases

Transforming growth factor β (TGF-β) belongs to a class of pleiotropic cytokines that are involved in the processes of embryonic development, wound healing, cell proliferation, and differentiation. Moreover, TGF-β is also regarded as a central regulator in the pathogenesis and development of various liver diseases because it contributes to almost all of the stages of disease progression. A range of liver cells are considered to secrete TGF-β ligands and express related receptors and, consequently, play a crucial role in the progression of liver disease via different signal pathways. In this manuscript, we review the role of the TGF-β signaling pathway in liver disease and the potential of targeting the TGF-β signaling in the pharmacological treatment of liver diseases.

Quercetin prevents ethanol-induced iron overload by regulating hepcidin through the BMP6/SMAD4 signaling pathway

Emerging evidence has demonstrated that chronic ethanol exposure induces iron overload, enhancing ethanol-mediated liver damage. The purpose of this study was to explore the effects of the naturally occurring compound quercetin on ethanol-induced iron overload and liver damage, focusing on the signaling pathway of the iron regulatory hormone hepcidin. Adult male C57BL/6J mice were pair-fed with isocaloric-Lieber De Carli diets containing ethanol (accounting for 30% of total calories) and/or carbonyl iron (0.2%) and treated with quecertin (100 mg/kg body weight) for 15 weeks. Mouse primary hepatocytes were incubated with ethanol (100 mM) and quercetin (100 μM) for 24 h. Mice exposed to either ethanol or iron presented significant fatty infiltration and iron deposition in the liver; these symptoms were exacerbated in mice cotreated with ethanol and iron. Quercetin attenuated the abnormity induced by ethanol and/or iron. Ethanol suppressed BMP6 and intranuclear SMAD4 as well as decreased hepcidin expression. These effects were partially alleviated by quercetin supplementation in mice and hepatocytes. Importantly, ethanol caused suppression of SMAD4 binding to the HAMP promoter and of hepcidin messenger RNA expression. These effects were exacerbated by anti-BMP6 antibody and partially alleviated by quercetin or human recombinant BMP6 in cultured hepatocytes. In contrast, co-treatment with iron and ethanol, especially exposure of iron alone, activated BMP6/SMAD4 pathway and up-regulated hepcidin expression, which was also normalized by quercetin in vivo. Quercetin prevented ethanol-induced hepatic iron overload different from what carbonyl iron diet elicited in the mechanism, by regulating hepcidin expression via the BMP6/SMAD4 signaling pathway.

Effect of alcohol exposure on hepatic superoxide generation and hepcidin expression

AIM: To understand the role of mitochondrial-produced superoxide (O₂^•-) in the regulation of iron-regulatory hormone, hepcidin by alcohol in the liver.

METHODS: For alcohol experiments, manganese superoxide dismutase knockout mice heterozygous for Sod2 gene expression (Sod2^+/-) and age-matched littermate control mice (LMC), expressing Sod2 gene on both alleles, were exposed to either 10% (w/v) ethanol in the drinking water or plain water (control) for 7 d. Total cellular O₂^•- levels in hepatocytes isolated from the livers of mice were measured by electron paramagnetic resonance spectroscopy. The mitochondrial-targeted, O₂^•--sensitive fluorogenic probe, MitoSOX Red and flow cytometry were utilized to measure O₂^•- in mitochondria. Gene and protein expression were determined by Taqman Real-time quantitative PCR and Western blotting, respectively.

RESULTS: Sod2^+/- mice expressed 40% less MnSOD protein (SOD2) in hepatocytes compared to LMC mice. The deletion of Sod2 allele did not alter the basal expression level of hepcidin in the liver. 10% ethanol exposure for 1 wk inhibited hepatic hepcidin mRNA expression three-fold both in Sod2^+/- and LMC mice. O₂^•- levels in hepatocytes of untreated Sod2^+/- mice were three-fold higher than in untreated LMC mice, as observed by electron paramagnetic resonance spectroscopy. O₂^•- levels in mitochondria of Sod2^+/ mice were four-fold higher than in mitochondria of untreated LMC mice, as measured by MitoSOX Red fluorescence and flow cytometry. Alcohol induced a two-fold higher increase in O₂^•- levels in hepatocytes of LMC mice than in Sod2^+/- mice compared to respective untreated counterparts. In contrast, 1 wk alcohol exposure did not alter mitochondrial O₂^•- levels in both Sod2^+/- and control mice.

CONCLUSION: Mitochondrial O₂^•- is not involved in the inhibition of liver hepcidin transcription and thereby regulation of iron metabolism by alcohol. These findings also suggest that short-term alcohol consumption significantly elevates O₂^•- levels in hepatocytes, which appears not to originate from mitochondria.

Metabolic Consequences of TGFb Stimulation in CulturedPrimary Mouse Hepatocytes Screened from Transcript Data with ModeScore

TGFβ signaling plays a major role in the reorganization of liver tissue upon injury and is an important driver of chronic liver disease. This is achieved by a deep impact on a cohort of cellular functions. To comprehensively assess the full range of affected metabolic functions, transcript changes of cultured mouse hepatocytes were analyzed with a novel method (ModeScore), which predicts the activity of metabolic functions by scoring transcript expression changes with 987 reference flux distributions, which yielded the following hypotheses. TGFβ multiplies down-regulation of most metabolic functions occurring in culture stressed controls. This is especially pronounced for tyrosine degradation, urea synthesis, glucuronization capacity, and cholesterol synthesis. Ethanol degradation and creatine synthesis are down-regulated only in TGFβ treated hepatocytes, but not in the control. Among the few TGFβ dependently up-regulated functions, synthesis of various collagens is most pronounced. Further interesting findings include: down-regulation of glucose export is postponed by TGFβ, TGFβ up-regulates the synthesis capacity of ketone bodies only as an early response, TGFβ suppresses the strong up-regulation of Vanin, and TGFβ induces re-formation of ceramides and sphingomyelin.

The hypoxia-inducible factor-C/EBPα axis controls ethanol-mediated hepcidin repression

Hepcidin is a liver-derived peptide hormone and the master regulator of systemic iron homeostasis. Decreased hepcidin expression is a common feature in alcoholic liver disease (ALD) and in mouse models of ethanol loading. Dysregulation of hepcidin signaling in ALD leads to liver iron deposition, which is a major contributing factor to liver injury. The mechanism by which hepcidin is regulated following ethanol treatment is unclear. An increase in liver hypoxia was observed in an acute ethanol-induced liver injury model. The hypoxic response is controlled by a family of hypoxia-inducible transcription factors (HIFs), which are composed of an oxygen-regulated alpha subunit (HIFα) and a constitutively present beta subunit, aryl hydrocarbon receptor nuclear translocator (HIFβ/Arnt). Disruption of liver HIF function reversed the repression of hepcidin following ethanol loading. Mouse models of liver HIF overexpression demonstrated that both HIF-1α and HIF-2α contribute to hepcidin repression in vivo. Ethanol treatment led to a decrease in CCAAT-enhancer-binding protein alpha (C/EBPα) protein expression in a HIF-dependent manner. Importantly, adenoviral rescue of C/EBPα in vivo ablated the hepcidin repression in response to ethanol treatment or HIF overexpression. These data provide novel insight into the regulation of hepcidin by hypoxia and indicate that targeting HIFs in the liver could be therapeutic in ALD.

Targeting the hepcidin-ferroportin axis to develop new treatment strategies for anemia of chronic disease and anemia of inflammation

Anemia of chronic disease (ACD) or anemia of inflammation is prevalent in patients with chronic infection, autoimmune disease, cancer, and chronic kidney disease. ACD is associated with poor prognosis and lower quality of life. Management of ACD using intravenous iron and erythropoiesis stimulating agents are ineffective for some patients and are not without adverse effects, driving the need for new alternative therapies. Recent advances in our understanding of the molecular mechanisms of iron regulation reveal that increased hepcidin, the iron regulatory hormone, is a key factor in the development of ACD. In this review, we will summarize the role of hepcidin in iron homeostasis, its contribution to the pathophysiology of ACD, and novel strategies that modulate hepcidin and its target ferroportin for the treatment of ACD.