Background
Systemic iron metabolism
Liver hepcidin acts as a major regulator of systemic iron metabolism
Brain iron metabolism
Hepcidin production and action in the brain
Methods | Study conditions | Main results | References |
---|---|---|---|
Expression measured with RT-PCR from human tissues | Physiological conditions | mRNA of hepcidin present in brain tissue | Krause et al. [31] |
Expression measured with RT-PCR from human tissues | Physiological conditions | mRNA of hepcidin present in spinal cord | Pigeon et al. [1] |
Expression measured with RT-PCR, in situ hybridization, immunohistochemistry in murine brain | Physiological conditions | Hepcidin expression detected with RT-PCR and in situ hybridization Immunohistochemistry showed a wide distribution of the protein across the brain tissue compared to narrow distribution of mRNA of hepcidin measured by in situ hybridization | Zechel et al. [32] |
Expression measured with RT-PCR and in situ hybridization, while protein levels were measured with western blotting and immunohistochemistry (rat brain samples) | Physiological conditions | Hepcidin expression was low with highest signal detected in choroidal plexus and to a lesser extent in blood vessels Protein levels were abundant, especially in blood vessels, choroidal plexus and cortical astrocytes in close proximity to blood vessels | Raha-Chowdhury et al. [33] |
Protein levels measured with western blotting and immunohistochemistry (mouse brain samples) | Physiological conditions | Abundant protein levels of hepcidin across the brain tissue | Raha et al. [35] |
Expression measured with RT-PCR, while protein levels were measured with western blotting (mouse brain and cell cultures) | Physiological and stimulated conditions | Hepcidin expression was abundant but still in low levels Hepcidin induced FPN downregulation in mouse brain Hepcidin decreases iron-release in cultured neurons due to FPN downregulation | Wang et al. [34] |
Expression measured with RT-PCR (human brain samples) | Physiological conditions | HJV mRNA was not observed Hepcidin, neogenin, TFR2, HFE mRNA was present | Hänninen et al. [69] |
Expression measured with RT-PCR, while protein levels were measured with western blotting (mouse brain) | Different stimulated conditions | TFR2 loss does not affect brain hepcidin protein levels | Pellegrino et al. [73] |
Expression measured with RT-PCR, while protein levels were measured with western blotting and immunohistochemistry (rat cultured cells) | Inflammation | Microglia react to LPS by producing IL-6 Astrocytes produce hepcidin in response to IL-6 secreted by microglia Hepcidin increases iron-load in neurons Inflammation has hepcidin-independent actions in reducing iron-export and enhancing iron-import in neurons | You et al. [54] |
Expression measured with RT-PCR, while protein levels were measured by western blotting and immunohistochemistry (rat cultured cells) | Inflammation and iron-stimulation | TNF-α, IL-6 and LPS increase cellular iron content in neurons TNF-α, IL-6 and LPS do not affect cellular iron content in astrocytes TNF-α, IL-6 and LPS increase cellular iron content in microglia TNF-α, IL-6 and LPS cause DMT1↑ and FPN↓ (protein levels) in neurons TNF-α, IL-6 and LPS cause DMT1↑ (protein levels) in astrocytes TNF-α, IL-6 and LPS cause DMT1↑ (protein levels) in microglia TNF-α, IL-6 and LPS cause DMT1↑ (mRNA) in neurons TNF-α, IL-6 and LPS cause DMT1↑ (mRNA), while LPS causes FPN↓ in astrocytes TNF-α, IL-6 and LPS cause DMT1↑ (mRNA), while TNF-α and LPS cause FPN↓ (mRNA) in microglia TNF-α, IL-6, LPS and FeNTA cause hepcidin↑(mRNA) in astrocytes and microglia but not in neurons | Urrutia et al. [56] |
Protein levels measured with western blotting and ELISA in rat cultured cells | Inflammation | LPS increases hepcidin expression in rat brain LPS increases IL-6 production from microglia IL-6 from microglia induces hepcidin production in neurons (via STAT3 pathway) No observed hepcidin↑ in neurons without co-cultured microglia due to LPS stimulation | Qian et al. [55] |
Expression measured with RT-PCR, while protein levels were measured with western blotting and immunohistochemistry (rat brain and cultured cells) | Iron-overload | Hepcidin↑ in rat brain and cultured cells Hepcidin mRNA↑ in cultured neurons in response to iron-overload | Sun et al. [64] |
Expression measured with RT-PCR, while protein levels were measured with western blotting and ELISA in rat brain and cultured cells | Iron-overload | Hepcidin reduces iron-load in rat brains Hepcidin induces TFR1↓, DMT1↓ and FPN↓ in BMEC Hepcidin induces TFR1↓, DMT1↓ and FPN↓ in neurons | Du et al. [59] |
Expression measured with RT-PCR, while protein levels were measured with western blotting and ELISA in rat brain and cultured cells | Physiological conditions | Hepcidin induces TFR1↓, DMT1↓ and FPN↓ in astrocytes TFR1↓ is realized through AMPK pathway | Du et al. [58] |
Expression measured by RT-PCR, while levels of chemicals were measured with ELISA | Inflammation induced by Aβ aggregates | Hepcidin pre-treatment reduces expression and secretion of IL-6 and TNF-α in astrocytes and microglia | Urrutia et al. [65] |
Hepcidin regulation in the brain
Hepcidin in brain diseases
Hepcidin in AD and Parkinsons disease (PD)
Methods | Brain disease | Main results | References |
---|---|---|---|
Expression measured with RT-PCR, while protein levels were measured with western blotting and immunohistochemistry (rat and mice brain samples) | Focal brain ischemia/reperfusion model | Hepcidin↑ in brain tissue Knock-down of hepcidin with siRNA causes FPN↑ and ferritin↓ | Ding et al. [52] |
Levels of protein measured with western blotting and ELISA (mice brain samples) | Intracerebral hemorrhage (ICH) model | Brain and serum hepcidin↑ Hepc−/− mice are protected from brain damage during ICH Injection of hepcidin increases brain damage Increased hepcidin inhibits BMVEC iron efflux The source of brain hepcidin are astrocytes Brain hepcidin upregulation is induced due to activation of TLR4 pathway Cellular iron-load is reduced by antagonizing local hepcidin | Xiong et al. [18] |
Protein levels measured with western blotting and immunohistochemistry (rat brain samples) | Subarachnoid hemorrhage model | Hepcidin↑ Hepcidin injections increase brain damage Hepcidin knock-down with siRNA decreases apoptosis and brain damage | Tan et al. [119] |
Serum protein levels measured with ELISA in 86 patients | ICH | Hepcidin↑ Higher hepcidin is associated with poorer outcome Hepcidin correlates with inflammatory markers Serum hepcidin is independently associated with mRS scorea | Xiong et al. [114] |
Serum protein levels measured with ELISA in 60 children | Acute ischemic stroke (AIS) | Hepcidin↑ Hepcidin is correlated with inflammatory markers | Azab et al. [111] |
Serum protein levels measured with ELISA in 74 patients | Ischemic stroke | Hepcidin↑ Hepcidin is correlated with inflammatory markers | Petrova et al. [113] |
Serum protein levels measured with ELISA in 31 patients | AIS | Hepcidin↑ | Slomka et al. [112] |
Protein levels measured with western blotting and immunohistochemistry in brain samples of humans and transgenic mice | Alzheimers disease (AD) | Hepcidin↓ in human samples Hepcidin↓ in mice samples in advanced stages of the disease Hepcidin staining is associated with hem-rich deposits Hepcidin distribution is observed in surviving neurons around amyloid plaques | Raha et al. [35] |
Serum protein levels measured with ELISA in 52 patients | AD | Hepcidin↑ Serum hepcidin correlates with CDR-SOBb | Sternberg et al. [89] |
Expression measured with RT-PCR and protein levels measured with western blotting and immunohistochemistry (neuronal cell cultures) | Parkinson disease model induced by 6-OHDA | Hepcidin mRNA↑ EGCG attenuates brain damage by reducing hepcidin expression | Chen et al. [94] |
Expression measured with RT-PCR (neuronal cell cultures) | Parkinson disease model induced by 6-OHDA | Hepcidin knock-down offers protection from 6-OHDA neurotoxicity | Xu et al. [95] |
Expression measured with RT-PCR (human brain samples) | Brain tumors | Hepcidin mRNA↓ in most tumor samples | Hänninen et al. [69] |
Serum protein levels measured with ELISA method in rats | Amyotrophic lateral sclerosis | Hepcidin↑ | Halon et al. [134] |
Protein levels measured with immunoblotting, ELISA and immunohistochemistry in 39 patients | Restless leg syndrome (RLS) | Prohepcidin↑ in brain tissue Prohepcidin↓ in cerebrospinal fluid in early-onset disease | Clardy et al. [140] |
Expression measured with RT-PCR in rat brains | Chronic mild stress | Hepcidin mRNA↑ Dalteparin lowers hepcidin expression Hepcidin expression is associated with cellular iron-overload and IL-6 expression | Farajdokht et al. [156] |