Heme and Iron Chelators Inhibit HIV-1 Through The Induction Of Heme Oxygenase 1, Ferroportin and IKBα

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2198-2198
Author(s):  
Namita Kumari ◽  
Sergei A Nekhai
Keyword(s):  
Cell Cycle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Heme Oxygenase ◽  
Molecular Mechanisms ◽  
Conflicts Of Interest ◽  
Iron Chelators ◽  
Heme Oxygenase 1 ◽  
Kinase C ◽  
Hiv 1

Abstract Background Recently, HIV-1 infection was shown to be efficiently inhibited in macrophages and T-cells treated with hemin that was added extracellularly 1,2. Hemin administration to humanized transgenic mice significantly reduced HIV-1 viral load 1. Suppression of HIV-1 by hemin was mediated through the induction of (HO-1)1, via a protein kinase C-dependent pathway2. The inhibitory effect of hemin could be reversed by protoporphyrin, an HO-1 inhibitor 2. Induction of heme oxygenase-1 (HO-1) by hemin was shown to inhibit HIV-1. We recently analyzed the role of HO-1 in protecting LPS-treated human macrophages against HIV-1 infection3. LPS-treated macrophages were negative for mature virions, expressed HO-1 and produced MIP1α, MIP1β and LD78β chemokines which led to a decreased CCR5 expression. Treatment with HO-1 inhibitor SnPP IX (tin protoporphyrin IX) increased HIV-1 replication and decreased secretion of MIP1α, MIP1β, and LD78β chemokines. HO-1 also affects several proteins involved in cell cycle progression, and cell cycle is critical for HIV-1 progression. Hypoxia leads to induction and stabilization of HIF-1α and is inhibitory to HIV-1 replication. NF-kB is important for basal and Tat-activated HIV-1 transcription. Here we analyzed factors involved in HIV-1 transcription affected by HO-1 expression. Results HIV-1 replication was reduced in THP1 cells treated with hemin. Subsequent treatment with hepcidin restored HIV-1 replication, suggesting that ferroportin plays a key role in the HIV-1 inhibition. Stable ferroportin knock down in THP1 cells led to the inability of hemin to inhibit HIV-1, again suggesting that ferroportin plays a key role in this process. In hemin-treated THP-1 cells, expression of p21, HIF-1α and IKBα mRNA was induced. The expression of IKBα, an inhibitor of NF-kB, reduced the level of p65 subunit of NF-kB. We obtained similar results in THP-1 cell treated with iron chelators, which also induced the expression of IKBα, HIF-1 and p21. THP-1 cells treated with hemin or iron chelators were arrested in G1 phase of cell cycle. Stable HIF-1a knockdown in promonocytic THP-1 cells increased HIV replication suggesting that HIF-1 might be a restriction factor for HIV-1. In contrast to iron chelators that inhibited enzymatic activity of CDK2 without affecting its protein level, hemin treatment reduced CDK2 expression at mRNA and protein levels. Conclusions Induction of HIF-1 regulatory pathway and iron export by ferroportin might protect hemin-treated THP-1 cells from HIV-1 infection. Additional molecular mechanisms of heme-mediated HIV-1 inhibition might also include NF-kB inhibition by IKBα and CDK2 inhibition leading to the inhibition of HIV-1 transcription. Our results point to novel therapeutics, such as the use of hemin and iron chelators, both of which are FDA approved for treatment for acute porphyries and iron overload. Acknowledgments This project was supported by NIH Research Grants 1SC1GM082325, 2G12RR003048, and P30HL107253. Literature 1. Devadas K, Dhawan S. Hemin activation ameliorates HIV-1 infection via heme oxygenase-1 induction. J Immunol. 2006;176(7):4252-4257. 2. Devadas K, Hewlett IK, Dhawan S. Lipopolysaccharide suppresses HIV-1 replication in human monocytes by protein kinase C-dependent heme oxygenase-1 induction. J Leukoc Biol. 2010;87(5):915-924. 3. Zhou ZH, Kumari N, Nekhai S, et al. Heme oxygenase-1 induction alters chemokine regulation and ameliorates human immunodeficiency virus-type-1 infection in lipopolysaccharide-stimulated macrophages. Biochem Biophys Res Commun. 2013;435(3):373-377. Disclosures: No relevant conflicts of interest to declare.

Mechanism of Hepatic Heme Oxygenase-1 Induction by Isoflurane

2006 ◽  
Vol 104 (1) ◽  
pp. 101-109 ◽  
Author(s):  
Alexander Hoetzel ◽  
Daniel Leitz ◽  
Rene Schmidt ◽  
Eva Tritschler ◽  
Inge Bauer ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase A2 ◽  
Heme Oxygenase ◽  
Kupffer Cell ◽  
Cell Function ◽  
Heme Oxygenase 1 ◽  
Gadolinium Chloride ◽  
Kinase C

Background The heme oxygenase pathway represents a major cell and organ protective system in the liver. The authors recently showed that isoflurane and sevoflurane up-regulate the inducible isoform heme oxygenase 1 (HO-1). Because the activating cascade remained unclear, it was the aim of this study to identify the underlying mechanism of this effect. Methods Rats were anesthetized with pentobarbital intravenously or with isoflurane per inhalation (2.3 vol%). Kupffer cell function was inhibited by dexamethasone or gadolinium chloride. Nitric oxide synthases were inhibited by either N(omega)-nitro-L-arginine methyl ester or S-methyl thiourea. N-acetyl-cysteine served as an antioxidant, and diethyldithiocarbamate served as an inhibitor of cytochrome P450 2E1. Protein kinase C and phospholipase A2 were inhibited by chelerythrine or quinacrine, respectively. HO-1 was analyzed in liver tissue by Northern blot, Western blot, immunostaining, and enzymatic activity assay. Results In contrast to pentobarbital, isoflurane induced HO-1 after 4-6 h in hepatocytes in the pericentral region of the liver. The induction was prevented in the presence of dexamethasone (P < 0.05) and gadolinium chloride (P < 0.05). Inhibition of nitric oxide synthases or reactive oxygen intermediates did not affect isoflurane-mediated HO-1 up-regulation. In contrast, chelerythrine (P < 0.05) and quinacrine (P < 0.05) resulted in a blockade of HO-1 induction. Conclusion The up-regulation of HO-1 by isoflurane in the liver is restricted to parenchymal cells and depends on Kupffer cell function. The induction is independent of nitric oxide or reactive oxygen species but does involve protein kinase C and phospholipase A2.

scholarly journals Protein Kinase C Signaling Mediates a Program of Cell Cycle Withdrawal in the Intestinal Epithelium

2000 ◽  
Vol 151 (4) ◽  
pp. 763-778 ◽  
Author(s):  
Mark R. Frey ◽  
Jennifer A. Clark ◽  
Olga Leontieva ◽  
Joshua M. Uronis ◽  
Adrian R. Black ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Intestinal Epithelium ◽  
Molecular Mechanisms ◽  
Model Systems ◽  
Intestinal Epithelial ◽  
Kinase C

Members of the protein kinase C (PKC) family of signal transduction molecules have been widely implicated in regulation of cell growth and differentiation, although the underlying molecular mechanisms involved remain poorly defined. Using combined in vitro and in vivo intestinal epithelial model systems, we demonstrate that PKC signaling can trigger a coordinated program of molecular events leading to cell cycle withdrawal into G0. PKC activation in the IEC-18 intestinal crypt cell line resulted in rapid downregulation of D-type cyclins and differential induction of p21waf1/cip1 and p27kip1, thus targeting all of the major G1/S cyclin-dependent kinase complexes. These events were associated with coordinated alterations in expression and phosphorylation of the pocket proteins p107, pRb, and p130 that drive cells to exit the cell cycle into G0 as indicated by concomitant downregulation of the DNA licensing factor cdc6. Manipulation of PKC isozyme levels in IEC-18 cells demonstrated that PKCα alone can trigger hallmark events of cell cycle withdrawal in intestinal epithelial cells. Notably, analysis of the developmental control of cell cycle regulatory molecules along the crypt–villus axis revealed that PKCα activation is appropriately positioned within intestinal crypts to trigger this program of cell cycle exit–specific events in situ. Together, these data point to PKCα as a key regulator of cell cycle withdrawal in the intestinal epithelium.

scholarly journals Lipopolysaccharide-Induced Heme Oxygenase-1 Expression in Human Monocytic Cells Is Mediated via Nrf2 and Protein Kinase C

2005 ◽  
Vol 175 (7) ◽  
pp. 4408-4415 ◽  
Author(s):  
Stuart A. Rushworth ◽  
Xi-Lin Chen ◽  
Nigel Mackman ◽  
Richard M. Ogborne ◽  
Maria A. O’Connell
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Heme Oxygenase ◽  
Heme Oxygenase 1 ◽  
Monocytic Cells ◽  
Kinase C

scholarly journals The Skin-Whitening Effects of Ectoine via the Suppression of α-MSH-Stimulated Melanogenesis and the Activation of Antioxidant Nrf2 Pathways in UVA-Irradiated Keratinocytes

Antioxidants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 63 ◽  
Author(s):  
You-Cheng Hseu ◽  
Xuan-Zao Chen ◽  
Yugandhar Vudhya Gowrisankar ◽  
Hung-Rong Yen ◽  
Jing-Yuan Chuang ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Molecular Mechanisms ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Hacat Cells ◽  
Skin Whitening ◽  
B16f10 Cells ◽  
Kinase C ◽  
Protein Kinase Ckii

Ultraviolet A (UVA)-irradiation induced reactive oxygen species (ROS) production mediates excessive melanogenesis in skin cells leading to pigmentation. We demonstrated the depigmenting and anti-melanogenic effects of Ectoine, a natural bacterial osmolyte, in UVA-irradiated human (HaCaT) keratinocytes, and the underlying molecular mechanisms were elucidated. HaCaT cells were pre-treated with low concentrations of Ectoine (0.5–1.5 μM) and assayed for various depigmenting and anti-melanogenic parameters. This pre-treatment significantly downregulated ROS generation, α-melanocyte-stimulating hormone (α-MSH) production, and proopiomelanocortin (POMC) expression in UVA-irradiated HaCaT cells. Also, antioxidant heme oxygenase-1 (HO-1), NAD(P)H dehydrogenase [quinone 1] (NQO-1), and γ-glutamate-cysteine ligase catalytic subunit (γ-GCLC) protein expressions were mediated via the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) whose knockdown indeed impaired this effect signifying the importance of the Nrf2 pathway. Ectoine was mediating the activation of Nrf2 via the p38, protein kinase B (also known as AKT), protein kinase C (PKC), and casein kinase II protein kinase (CKII) pathways. The conditioned medium obtained from the Ectoine pre-treated and UVA-irradiated HaCaT cells downregulated the tyrosinase, tyrosinase-related protein-1 and -2 (TRP-1/-2), cyclic AMP (c-AMP) protein kinase, c-AMP response element-binding protein (CREB), and microphthalmia-associated transcription factor (MITF) expressions leading to melanoma B16F10 cells having inhibited melanin synthesis. Interestingly, this anti-melanogenic effect in α-MSH-stimulated B16F10 cells was observable only at 50–400 μM concentrations of Ectoine, signifying the key role played by Ectoine (0.5–1 μM)-treated keratinocytes in skin whitening effects. We concluded that Ectoine could be used as an effective topical natural cosmetic agent with depigmenting and anti-melanogenic efficacy.

TNF-α and IL-1α induce heme oxygenase-1 via protein kinase C, Ca2+, and phospholipase A2 in endothelial cells

1999 ◽  
Vol 276 (5) ◽  
pp. H1493-H1501 ◽  
Author(s):  
Christi M. Terry ◽  
Jennifer A. Clikeman ◽  
John R. Hoidal ◽  
Karleen S. Callahan
Keyword(s):  
Endothelial Cells ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Heme Oxygenase ◽  
Calcium Ionophore ◽  
Heme Oxygenase 1 ◽  
Acetoxymethyl Ester ◽  
Cytokine Induction ◽  
Kinase C ◽  
Tnf Α

Heme oxygenase-1 (HO-1), an enzyme important in protection against oxidant stress, is induced in human vascular endothelial cells by the cytokines tumor necrosis factor-α (TNF-α) and interleukin-1α (IL-1α). However, the signaling mediators that regulate the induction are not known. This study examined the involvement of protein kinase C (PKC), phospholipase A2(PLA2), calcium, and oxidants in cytokine induction of HO-1. Acute exposure to the PKC activator phorbol 12-myristate 13-acetate (PMA) stimulated HO-1 mRNA. However, prolonged exposure, which downregulates most PKC isoforms, blocked induction of HO-1 mRNA by IL-1α and TNF-α. Additionally, the phosphatase inhibitors okadaic acid and calyculin enhanced cytokine induction of HO-1. Mepacrine, a PLA2 inhibitor, prevented HO-1 induction by cytokine, suggesting a role for arachidonate, the product of PLA2hydrolysis of phospholipids, in HO-1 expression. The intracellular calcium chelator 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid acetoxymethyl ester (BAPTA-AM) blocked cytokine induction of HO-1. Paradoxically, the calcium ionophore A-23187 prevented HO-1 induction by cytokine but not by PMA. Finally, the oxidant scavenger N-acetylcysteine inhibited HO-1 induction by cytokines. These results demonstrate that TNF-α and IL-1α induction of HO-1 requires PKC-mediated phosphorylation and PLA2 activation as well as oxidant generation.

scholarly journals Insulin Up-Regulates Heme Oxygenase-1 Expression in 3T3-L1 Adipocytes via PI3-Kinase- and PKC-Dependent Pathways and Heme Oxygenase-1–Associated MicroRNA Downregulation

Endocrinology ◽  
2010 ◽  
Vol 152 (2) ◽  
pp. 384-393 ◽  
Author(s):  
Chih-Ling Chang ◽  
Lo-Chun Au ◽  
Seng-Wong Huang ◽  
Ching Fai Kwok ◽  
Low-Tone Ho ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Heme Oxygenase ◽  
Pi3 Kinase ◽  
Dose Effect ◽  
In Vivo Study ◽  
Heme Oxygenase 1 ◽  
Akt Inhibitor ◽  
Kinase C

Abstract Heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme catabolism, has antioxidant, antiinflammatory, and antiapoptotic effects in many physiological systems. HO-1 activity in obese mice is lower than in controls, and a sustained increase in HO-1 protein levels ameliorates insulin resistance and compensatory hyperinsulinemia. In the present study, we explored the regulatory effect of insulin on HO-1 expression in 3T3-L1 adipocytes and the underlying mechanism. We investigated the time- and dose-effect of insulin on HO-1 expression in 3T3-L1 adipocytes. Using specific inhibitors acting on insulin signaling pathways, we clarified the involvement of insulin downstream signaling molecules in insulin-regulated HO-1 expression. We also investigated the involvement of microRNAs (miRNAs) in insulin-regulated HO-1 expression using microarray and real-time RT-PCR assays. In an in vivo study, we performed insulin/glucose coinfusion in rats to increase circulating insulin levels for 8 h, then measured adipocyte HO-1 expression. Insulin caused a significant increase in HO-1 expression that was time- and dose-dependent, and this effect was blocked by inhibition of phosphatidylinositol 3 (PI3)-kinase activation using LY294002 (50 μM) or of protein kinase C activation using Ro-318220 (2 μM), but not by an Akt inhibitor, triciribine (10 μM). Furthermore, incubation of 3T3-L1 adipocytes with 100 nm insulin resulted in a significant decrease in levels of the miRNAs mir-155, mir-183, and mir-872, and this effect was also blocked by pretreatment with LY294002 or Ro-318220, but not triciribine. An in vivo study in rats showed that 8 h of a hyperinsulinemic euglycemic state resulted in a significant increase in adipocyte HO-1 expression. In conclusion, insulin increases HO-1 protein expression in 3T3-L1 adipocytes via PI3-kinase and protein kinase C-dependent pathways and miRNAs down-regulation.

Novel 2-Phenyl-1-Pyridin-2yl-Ethanone (PpY) Based Iron Chelators Increase Expression of IkBα and Heme Oxygenase-1 and Inhibit HIV-1

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1052-1052
Author(s):  
Namita Kumari ◽  
Min Xu ◽  
Dmytro Kovlaskyy ◽  
Subhash Dhawan ◽  
Sergei Nekhai
Keyword(s):  
Heme Oxygenase ◽  
Conflicts Of Interest ◽  
Iron Chelators ◽  
Heme Oxygenase 1 ◽  
Intracellular Iron ◽  
Experimental Conditions ◽  
Cyclin T1 ◽  
Hiv 1

Abstract Abstract 1052 HIV-1 transcription is activated by HIV-1 Tat protein, which recruits CDK9/cyclin T1 and other host transcriptional co-activators to the HIV-1 promoter. Tat itself is phosphorylated by cell cycle kinase 2 (CDK2) and inhibition of CDK2 by small interfering RNA or iron chelators inhibits HIV-1 transcription. HIV-1 transcription is also activated by NF-kB that binds to HIV-1 LTR independent to Tat but can also be recruited Tat-dependently by CDK9/cyclin T1. Recently, induction of heme oxygenase-1 (HO-1) by hemin was shown to inhibit HIV-1 in vitro and in vivo. Here, we analyzed the effect of novel phenyl-1-pyridin-2yl-ethanone (PPY) based iron chelators, PPYeT and PPYaT, on HIV-1. Both chelators efficiently inhibited one round of HIV-1 replication in T cells at low nanomolar IC50s without exhibiting cytotoxicity at 24 hrs incubation. The iron chelators efficiently bound intracellular labile iron as it was determined in calcein binding assays. Because we previously showed that iron chelators inhibited the activity of CDK9, we analyzed expression of several cellular genes dependent on CDK9. Unexpectedly, chelators were found to induce the expression of IkBα, an inhibitor of NF-kB (Fig1). Treatment with the iron chelators retained NF-kB in cytoplasm of the treated cells suggesting reduction in NF-kB in nucleus (Fig2). The chelators were also shown to induce HO-1 expression in cultured monocytes, likely to do a decrease of intracellular iron pool. This effect of iron chelators mimicked the effect of hemin treatment which also induced HO-1 and inhibited HIV-1 infection in our experimental conditions. Low nanomolar IC50s for the PPY-based iron chelators and lack of toxicity suggest their potential usefulness as future anti-retroviral therapeutics. Further studies are needed to investigate additional targets for iron chelators in HIV-1 life cycle that may include reverse transcription and capsid assembly. Therefore iron chelators need to be carefully assessed not only to understand the mechanism but also as a therapeutic strategy. Acknowledgments. This work was supported NIH Research Grants SC1GM082325, R25 HL003679, 2G12RR003048, 8G12MD007597, K25GM097501 and 1P30HL107253. Disclosures: No relevant conflicts of interest to declare.

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