scholarly journals Heme Oxygenase-1 Regulates Ferrous Iron and Foxo1 in Control of Hepatic Gluconeogenesis

2021 ◽  
Author(s):  
Ada Admin ◽  
Wang Liao ◽  
Wanbao Yang ◽  
Zheng Shen ◽  
Weiqi Ai ◽  
...  

The liver is a key player for maintaining glucose homeostasis. Excessive hepatic glucose production is considered to be a key for the onset of type 2 diabetes mellitus. The primary function of heme oxygenase-1 (HO1) is to catalyze the degradation of heme into biliverdin, ferrous iron, and carbon monoxide. Previous studies have demonstrated that the degradation of heme by HO1 in the liver results in mitochondrial dysfunction and drives insulin resistance. In this study, by overexpressing HO1 in hepatocytes and mice, we showed that HO1 promotes gluconeogenesis in a Foxo1-dependent manner. Importantly, HO1 overexpression increased the generation of ferrous iron in the liver, which further activates NF-<a>κB</a> and phosphorylates Foxo1 at Ser273 to enhance gluconeogenesis. We further assessed the role of HO1 in insulin-resistant L-DKO (liver-specific knockout of IRS1 and IRS2 genes) mice, which exhibit upregulation of HO1 in the liver and hepatic ferrous iron overload. HO1 knockdown by shRNA or treatment of iron chelator rescued the aberrant gluconeogenesis in L-DKO mice. In addition, we found that systemic iron overload promotes gluconeogenesis by activating hepatic PKA→Foxo1 axis. Thus, our results demonstrate the role of HO1 in regulating hepatic iron status and Foxo1 to control gluconeogenesis and blood glucose.

2021 ◽  
Author(s):  
Ada Admin ◽  
Wang Liao ◽  
Wanbao Yang ◽  
Zheng Shen ◽  
Weiqi Ai ◽  
...  

The liver is a key player for maintaining glucose homeostasis. Excessive hepatic glucose production is considered to be a key for the onset of type 2 diabetes mellitus. The primary function of heme oxygenase-1 (HO1) is to catalyze the degradation of heme into biliverdin, ferrous iron, and carbon monoxide. Previous studies have demonstrated that the degradation of heme by HO1 in the liver results in mitochondrial dysfunction and drives insulin resistance. In this study, by overexpressing HO1 in hepatocytes and mice, we showed that HO1 promotes gluconeogenesis in a Foxo1-dependent manner. Importantly, HO1 overexpression increased the generation of ferrous iron in the liver, which further activates NF-<a>κB</a> and phosphorylates Foxo1 at Ser273 to enhance gluconeogenesis. We further assessed the role of HO1 in insulin-resistant L-DKO (liver-specific knockout of IRS1 and IRS2 genes) mice, which exhibit upregulation of HO1 in the liver and hepatic ferrous iron overload. HO1 knockdown by shRNA or treatment of iron chelator rescued the aberrant gluconeogenesis in L-DKO mice. In addition, we found that systemic iron overload promotes gluconeogenesis by activating hepatic PKA→Foxo1 axis. Thus, our results demonstrate the role of HO1 in regulating hepatic iron status and Foxo1 to control gluconeogenesis and blood glucose.


Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1718-P ◽  
Author(s):  
WANG LIAO ◽  
WANBAO YANG ◽  
QUAN PAN ◽  
ZHENG SHEN ◽  
WEIQI AI ◽  
...  

2000 ◽  
Vol 278 (4) ◽  
pp. R956-R963 ◽  
Author(s):  
Jean-Michel Weber ◽  
Deena S. Shanghavi

The rate of hepatic glucose production (Ra glucose) of rainbow trout ( Oncorhynchus mykiss) was measured in vivo by continuous infusion of [6-3H]glucose and in vitro on isolated hepatocytes to examine the role of epinephrine (Epi) in its regulation. By elevating Epi concentration and/or blocking β-adrenoreceptors with propranolol (Prop), our goals were to investigate the mechanism for Epi-induced hyperglycemia to determine the possible role played by basal Epi concentration in maintaining resting Ra glucose and to assess indirect effects of Epi in the intact animal. In vivo infusion of Epi caused hyperglycemia (3.75 ± 0.16 to 8.75 ± 0.54 mM) and a twofold increase in Ra glucose (6.57 ± 0.79 to 13.30 ± 1.78 μmol ⋅ kg− 1 ⋅ min− 1, n = 7), whereas Prop infusion decreased Ra from 7.65 ± 0.92 to 4.10 ± 0.56 μmol ⋅ kg− 1 ⋅ min− 1( n = 10). Isolated hepatocytes increased glucose production when treated with Epi, and this response was abolished in the presence of Prop. We conclude that Epi-induced trout hyperglycemia is entirely caused by an increase in Ra glucose, because the decrease in the rate of glucose disappearance normally seen in mammals does not occur in trout. Basal circulating levels of Epi are involved in maintaining resting Ra glucose. Epi stimulates in vitro glucose production in a dose-dependent manner, and its effects are mainly mediated by β-adrenoreceptors. Isolated trout hepatocytes produce glucose at one-half the basal rate measured in vivo, even when diet, temperature, and body size are standardized, and basal circulating Epi is responsible for part of this discrepancy. The relative increase in Ra glucose after Epi stimulation is similar in vivo and in vitro, suggesting that indirect in vivo effects of Epi, such as changes in hepatic blood flow or in other circulating hormones, do not play an important role in the regulation of glucose production in trout.


2019 ◽  
Vol 241 (3) ◽  
pp. 265-278
Author(s):  
Wanbao Yang ◽  
Hui Yan ◽  
Quan Pan ◽  
James Zheng Shen ◽  
Fenghua Zhou ◽  
...  

Glucagon promotes hepatic glucose production maintaining glucose homeostasis in the fasting state. Glucagon maintains at high level in both diabetic animals and human, contributing to hyperglycemia. Mitochondria, a major place for glucose oxidation, are dysfunctional in diabetic condition. However, whether hepatic mitochondrial function can be affected by glucagon remains unknown. Recently, we reported that FOXO1 is an important mediator in glucagon signaling in control of glucose homeostasis. In this study, we further assessed the role of FOXO1 in the action of glucagon in the regulation of hepatic mitochondrial function. We found that glucagon decreased the heme production in a FOXO1-dependent manner, suppressed heme-dependent complex III (UQCRC1) and complex IV (MT-CO1) and inhibited hepatic mitochondrial function. However, the suppression of mitochondrial function by glucagon was largely rescued by deleting the Foxo1 gene in hepatocytes. Glucagon tends to reduce hepatic mitochondrial biogenesis by attenuating the expression of NRF1, TFAM and MFN2, which is mediated by FOXO1. In db/db mice, we found that hepatic mitochondrial function was suppressed and expression levels of UQCRC1, MT-CO1, NRF1 and TFAM were downregulated in the liver. These findings suggest that hepatic mitochondrial function can be impaired when hyperglucagonemia occurs in the patients with diabetes mellitus, resulting in organ failure.


2018 ◽  
Vol 314 (5) ◽  
pp. F702-F714 ◽  
Author(s):  
Oreoluwa Adedoyin ◽  
Ravindra Boddu ◽  
Amie Traylor ◽  
Jeremie M. Lever ◽  
Subhashini Bolisetty ◽  
...  

Ferroptosis is an iron-dependent form of regulated nonapoptotic cell death, which contributes to damage in models of acute kidney injury (AKI). Heme oxygenase-1 (HO-1) is a cytoprotective enzyme induced in response to cellular stress, and is protective against AKI because of its antiapoptotic and anti-inflammatory properties. However, the role of HO-1 in regulating ferroptosis is unclear. The purpose of this study was to elucidate the role of HO-1 in regulating ferroptotic cell death in renal proximal tubule cells (PTCs). Immortalized PTCs obtained from HO-1+/+ and HO-1−/− mice were treated with erastin or RSL3, ferroptosis inducers, in the presence or absence of antioxidants, an iron source, or an iron chelator. Cells were assessed for changes in morphology and metabolic activity as an indicator of cell viability. Treatment of HO-1+/+ PTCs with erastin resulted in a time- and dose-dependent increase in HO-1 gene expression and protein levels compared with vehicle-treated controls. HO-1−/− cells showed increased dose-dependent erastin- or RSL3-induced cell death in comparison to HO-1+/+ PTCs. Iron supplementation with ferric ammonium citrate in erastin-treated cells decreased cell viability further in HO-1−/− PTCs compared with HO-1+/+ cells. Cotreatment with ferrostatin-1 (ferroptosis inhibitor), deferoxamine (iron chelator), or N-acetyl-l-cysteine (glutathione replenisher) significantly increased cell viability and attenuated erastin-induced ferroptosis in both HO-1+/+ and HO-1−/− PTCs. These results demonstrate an important antiferroptotic role of HO-1 in renal epithelial cells.


Biologia ◽  
2012 ◽  
Vol 67 (4) ◽  
Author(s):  
Maher Abdalla ◽  
Mary Mathahs ◽  
Iman Ahmad

AbstractHeme oxygenase-1 (HO-1) is the rate limiting enzyme in heme catabolism and degrades heme to carbon monoxide, biliverdin, and ferrous iron. HO-1 transcriptional induction occurs in response to multiple forms of chemical, physical stress and cytokines. HO-1 confers cytoprotection by inhibiting apoptosis, oxidative stress, and inflammation. Hepatitis C virus (HCV) is a major cause of cirrhosis and hepatocellular carcinoma. It has been shown that HO-1 induction and HO-1 products interfere with replication of HCV and markedly decreased HCV replication. However, a growing body of evidence indicates that induction of HO-1 may be involved in carcinogenesis and can play a role in the metastasis and growth of tumors. The antioxidant, antiviral activity of HO-1 makes it the cytoprotective enzyme for liver tissue in HCV infection, and induction of HO-1 can be suggested as a future therapeutic approach. However, the role of HO-1 in tumor growth should not be ignored.


Diabetes ◽  
1986 ◽  
Vol 35 (2) ◽  
pp. 186-191 ◽  
Author(s):  
I. Hansen ◽  
R. Firth ◽  
M. Haymond ◽  
P. Cryer ◽  
R. Rizza

2018 ◽  
Vol 24 (20) ◽  
pp. 2283-2302 ◽  
Author(s):  
Vivian B. Neis ◽  
Priscila B. Rosa ◽  
Morgana Moretti ◽  
Ana Lucia S. Rodrigues

Heme oxygenase (HO) family catalyzes the conversion of heme into free iron, carbon monoxide and biliverdin. It possesses two well-characterized isoforms: HO-1 and HO-2. Under brain physiological conditions, the expression of HO-2 is constitutive, abundant and ubiquitous, whereas HO-1 mRNA and protein are restricted to small populations of neurons and neuroglia. HO-1 is an inducible enzyme that has been shown to participate as an essential defensive mechanism for neurons exposed to oxidant challenges, being related to antioxidant defenses in certain neuropathological conditions. Considering that neurodegenerative diseases (Alzheimer’s Disease (AD), Parkinson’s Disease (PD) and Multiple Sclerosis (MS)) and neuropsychiatric disorders (depression, anxiety, Bipolar Disorder (BD) and schizophrenia) are associated with increased inflammatory markers, impaired redox homeostasis and oxidative stress, conditions that may be associated with alterations in HO-levels/activity, the purpose of this review is to present evidence on the possible role of HO-1 in these Central Nervous System (CNS) diseases. In addition, the possible therapeutic potential of targeting brain HO-1 is explored in this review.


2017 ◽  
Vol 18 (6) ◽  
pp. 674-686 ◽  
Author(s):  
Aleksandra Piechota-Polanczyk ◽  
Alicja Jozkowicz

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