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Molecular Medicine 2014

Articles from this Volume

Jing Huang, Xiu-Da Shen, Shi Yue, Jianjun Zhu, Feng Gao, Yuan Zhai, Ronald W Busuttil, Bibo Ke, and Jerzy W Kupiec-Weglinski

Macrophages are instrumental in the pathophysiology of liver ischemia/reperfusion injury (IRI). Although Nrf2 regulates macrophage-specific heme oxygenase-1 (HO-1) antioxidant defense, it remains unknown whether HO-1 induction might rescue macrophage Nrf2-dependent antiinflammatory functions. This study explores the mechanisms by which the Nrf2–HO-1 axis regulates sterile hepatic inflammation responses after adoptive transfer of ex vivo modified HO-1 overexpressing bone marrow–derived macrophages (BMMs). Livers in Nrf2-deficient mice preconditioned with Ad-HO-1 BMMs, but not Ad-β-Gal-BMMs, ameliorated liver IRI (at 6 h of reperfusion after 90 min of warm ischemia), evidenced by improved hepatocellular function (serum alanine aminotransferase [sALT] levels) and preserved hepatic architecture (Suzuki histological score). Treatment with Ad-HO-1 BMMs decreased neutrophil accumulation, proinflammatory mediators and hepatocellular necrosis/apoptosis in ischemic livers. Moreover, Ad-HO-1 transfection of Nrf2-deficient BMMs suppressed M1 (Nos2+) while promoting the M2 (Mrc-1/Arg-1+) phenotype. Unlike in controls, Ad-HO-1 BMMs increased the expression of Notch1, Hes1, phosphorylation of Stat3 and Akt in IR-stressed Nrf2-deficient livers as well as in lipopolysaccharide (LPS)-stimulated BMMs. Thus, adoptive transfer of ex vivo generated Ad-HO-1 BMMs rescued Nrf2-dependent antiinflammatory phenotype by promoting Notch1/Hes1/Stat3 signaling and reprogramming macrophages toward the M2 phenotype. These findings provide the rationale for a novel clinically attractive strategy to manage IR liver inflammation/damage.

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Supplemental Data
Posted by Sheila Platt on Oct 14, 2014 10:26 AM CDT
Harold H Bach IV, Yee M Wong, Abhishek Tripathi, Amanda M Nevins, Richard L Gamelli, Brian F Volkman, Kenneth L Byron, and Matthias Majetschak

Chemokine (C-X-C motif) receptor (CXCR) 4 and atypical chemokine receptor (ACKR) 3 ligands have been reported to modulate cardiovascular function in various disease models. The underlying mechanisms, however, remain unknown. Thus, it was the aim of the present study to determine how pharmacological modulation of CXCR4 and  ACKR3 regulate cardiovascular function. In vivo administration of TC14012, a CXCR4 antagonist and ACKR3 agonist, caused cardiovascular collapse in normal animals. During the cardiovascular stress response to hemorrhagic shock, ubiquitin, a CXCR4 agonist, stabilized blood pressure, whereas coactivation of CXCR4 and ACKR3 with CXC chemokine ligand 12 (CXCL12), or blockade of CXCR4 with AMD3100 showed opposite effects. While CXCR4 and ACKR3 ligands did not affect myocardial function, they selectively altered vascular reactivity upon α1-adrenergic receptor (AR) activation in pressure myography experiments. CXCR4 activation with ubiquitin enhanced α1-ARmediated vasoconstriction, whereas ACKR3 activation with various natural and synthetic ligands antagonized α1-AR-mediated vasoconstriction. The opposing effects of CXCR4 and ACKR3 activation by CXCL12 could be dissected pharmacologically. CXCR4 and ACKR3 ligands did not affect vasoconstriction upon activation of voltage-operated Ca2+ channels or endothelin receptors. Effects of CXCR4 and ACKR3 agonists on vascular α 1-AR responsiveness were independent of the endothelium. These findings suggest that CXCR4 and ACKR3 modulate α1-AR reactivity in vascular smooth muscle and regulate hemodynamics in normal and pathological conditions. Our observations point toward CXCR4 and ACKR3 as new pharmacological targets to control vasoreactivity and blood pressure.

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Supplemental Data
Posted by Sheila Platt on Oct 13, 2014 10:03 AM CDT
Paraskevi Christoforou, Panagiotis F Christopoulos, and Michael Koutsilieris

Although androgen receptor (AR) signaling is the main molecular tool regulating growth and function of the prostate gland, estrogen receptor β (ERβ) is involved in the differentiation of prostatic epithelial cells and numerous antiproliferative actions on prostate cancer cells. However, ERβ splice variants have been associated with prostate cancer initiation and progression mechanisms. ERβ is promising as an anticancer therapy and in the prevention of prostate cancer. Herein, we review the recent experimental findings of ERβ signaling in the prostate.

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Posted by Sheila Platt on Oct 2, 2014 10:38 AM CDT
Michal G Shapira, Boris Khalfin, Eli C Lewis, Abraham H Parola, and Ilana Nathan

Autophagy is involved in both the cell protective and the cell death process but its mechanism is largely unknown. The present work unravels a novel intracellular mechanism by which the serpin α1-antitrypsin (AAT) acts as a novel negative regulator of autophagic cell death. For the first time, the role of intracellularly synthesized AAT, other than in liver cells, is demonstrated. Autophagic cell death was induced by N-α-tosyl-L-phenylalanine chloromethyl ketone (TPCK) and tamoxifen. By utilizing a fluorescently tagged TPCK analog, AAT was “fished out” (pulled out) as a TPCK intracellular protein target. The interaction was further verified by competition binding experiments. Both inducers caused downregulation of AAT expression associated with activation of trypsin-like proteases. Furthermore, silencing AAT by siRNA induced autophagic cell death. Moreover, AAT administration to cultured cells prevented autophagic cell death. This new mechanism could have implications in the treatment of diseases by the regulation of AAT levels in which autophagy has a detrimental function. Furthermore, the results imply that the high synthesis of endogenous AAT by cancer cells could provide a novel resistance mechanism of cancer against autophagic cell death.

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Posted by Leah Caracappa on Sep 25, 2014 11:06 AM CDT
Elias S Vasiliadis, Spyros G Pneumaticos, Demitrios S Evangelopoulos, and Athanasios G Papavassiliou

Disc degeneration is the most common cause of back pain in adults and has enormous socioeconomic implications. Conservative management is ineffective in most cases, and results of surgical treatment have not yet reached desirable standards. Biologic treatment options are an alternative to the above conventional management and have become very attractive in recent years. The present review highlights the currently available biologic treatment options in mild and moderate disc degeneration, where a potential for regeneration still exists. Biologic treatment options include protein-based and cell-based therapies. Proteinbased therapies involve administration of biologic factors into the intervertebral disc to enhance matrix synthesis, delay degeneration or impede inflammation. These factors can be delivered by an intradiscal injection, alone or in combination with cells or tissue scaffolds and by gene therapy. Cell-based therapies comprise treatment strategies that aim to either replace necrotic or apoptotic cells, or minimize cell death. Cell-based therapies are more appropriate in moderate stages of degenerated disc disease, when cell population is diminished; therefore, the effect of administration of growth factors would be insufficient. Although clinical application of biologic treatments is far from being an everyday practice, the existing studies demonstrate promising results that will allow the future design of more sophisticated methods of biologic intervention to treat intervertebral disc degeneration.

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Posted by Sheila Platt on Sep 18, 2014 8:27 AM CDT
JanWillem Duitman, Roberta R Ruela-de-Sousa, Kun Shi, Onno J de Boer, Keren S Borensztajn, Sandrine Florquin, Maikel P Peppelenbosch, C Arnold Spek

Accumulating evidence shows that protease-activated receptor-1 (PAR-1) plays an important role in the development of fibrosis, including lung fibrosis. However, whether PAR-1 also plays a role in the development of skin fibrosis remains elusive. The aim of this study was to determine the role of PAR-1 in the development of skin fibrosis. To explore possible mechanisms by which PAR-1 could play a role, human dermal fibroblasts and keratinocytes were stimulated with specific PAR-1 agonists or antagonists. To investigate the role of PAR-1 in skin fibrosis, we subjected wild-type and PAR-1-deficient mice to a model of bleomycin-induced skin fibrosis. PAR-1 activation leads to increased proliferation and extra cellular matrix (ECM) production, but not migration of human dermal fibroblasts (HDF) in vitro. Moreover, transforming growth factor (TGF)-β production was increased in keratinocytes upon PAR-1 activation,
but not in HDF. The loss of PAR-1 in vivo significantly attenuated bleomycin-induced skin fibrosis. The bleomycin-induced increase in dermal thickness and ECM production was reduced significantly in PAR-1-deficient mice compared with wild-type mice. Moreover, TGF-β expression and the number of proliferating fibroblasts were reduced in PAR-1-deficient mice although the difference did not reach statistical significance. This study demonstrates that PAR-1 contributes to the development of skin fibrosis and we suggest that PAR-1 potentiates the fibrotic response mainly by inducing fibroblast proliferation and ECM production.

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Posted by Sheila Platt on Sep 18, 2014 8:13 AM CDT
Shao-lin Ma, Ya-peng Hu, Fang Wang, Zhen-cong Huang, Yi-fan Chen, Xiao-kun Wang, and Li-wu Fu

Lapatinib, a tyrosine kinase inhibitor, is used in the treatment of advanced or metastatic breast cancer overexpressing human epidermal receptor 2 (HER2). Lapatinib can modulate the function of ATP-binding cassette (ABC) transporters (ABCB1 and ABCG2), which are the major mechanism responsible for multidrug resistance (MDR) in cancer. In this study, we investigated the effect of lapatinib on multidrug resistance–associated protein 1 (MRP1 [ABCC1]), MRP2 (ABCC2), MRP4 (ABCC4) and lung relative resistance protein (LRP) drug efflux pumps. We demonstrated that lapatinib could enhance the efficacy of conventional chemotherapeutic agents in MRP1-overexpressing cells in vitro and in vivo, but no effect in MRP2-, MPR4- and LRP-overexpressing cells. Furthermore, lapatinib significantly increased the accumulation of rhodamine 123 (Rho123) and doxorubicin (DOX) in MRP1-overexpressing cells. However, lapatinib did not alter the protein or mRNA expression levels of MRP1. Further studies showed that
the level of phosphorylation of AKT and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) were not altered at the indicated concentrations of lapatinib. In conclusion, lapatinib enhanced the efficacy of conventional chemotherapeutic agents in MRP1-overexpressing cells by inhibiting MRP1 transport function without altering the level of AKT or ERK1/2 phosphorylation. These findings will encourage the clinical research of lapatinib combined with conventional chemotherapeutic drugs in MRP1-overexpressing cancer patients.

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Posted by Sheila Platt on Sep 8, 2014 12:31 PM CDT
James DeVoti, Lynda Hatam, Alexandra Lucs, Ali Afzal, Allan Abramson, Bettie Steinberg, and
Vincent Bonagura

Recurrent respiratory papillomatosis (RRP) is a rare, chronic disease caused by human papillomaviruses (HPVs) types 6 and 11 that is characterized by the polarization of adaptive immune responses that support persistent HPV infection. Respiratory papillomas express elevated mRNA levels of IL-36γ, a proinflammatory cytokine in comparison to autologous clinically normal laryngeal tissues; however there is no evidence of inflammation in these lesions. Consistent with this, respiratory papillomas do not contain TH1-like CD4+ T-cells or cytotoxic CD8+ T-cells, but instead contain a predominance of TH2-like and T regulatory cells (Tregs). In addition, papillomas also are infiltrated with immature Langerhans cells (iLCs). In this study, we show that papilloma cells express IL- 36γ protein, and that human keratinocytes transduced with HPV11 have reduced IL-36γ secretion. We now provide the first evidence that peripheral blood-derived iLCs respond to IL-36γ by expressing inflammatory cytokines and chemokines. When stimulated with IL-36γ, iLCs from patients with RRP had lower expression levels of the TH2-like chemokine CCL-20 as compared with controls. Patients’ iLCs also had decreased steady state levels of CCL-1, which is a proinflammatory chemokine. Moreover, CCL-1 levels in iLCs inversely correlated with the severity of RRP. The combined decrease of TH1- and a TH2-like chemokines by iLCs from patients could have consequences in the priming of IFN-γ expression by CD8+ T-cells. Taken together, our results suggest that, in RRP, there is a defect in the proinflammatory innate immune responses made by iLCs in response to IL-36γ. The consequence of this defect may lead to persistent HPV infection by failing to support an effective HPV-specific, TH1-like and/or Tc1-like adaptive  response, thus resulting in the predominant TH2-like and/or Treg micromilieu present in papillomas.

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Posted by Sheila Platt on Aug 28, 2014 8:10 AM CDT
Tarek El-Hamoly, Csaba Hegedűs, Petra Lakatos, Katalin Kovács, Péter Bai, Mona A El-Ghazaly, Ezzeddin S El-Denshary, Éva Szabó, and László Virág

Poly(ADP-ribosyl)ation (PARylation) is a protein modification reaction regulating various diverse cellular functions ranging from metabolism, DNA repair and transcription to cell death. We set out to investigate the role of PARylation in wound healing, a highly complex process involving various cellular and humoral factors. We found that topically applied poly[ADP-ribose] polymerase (PARP) inhibitors 3-aminobenzamide and PJ-34 accelerated wound closure in a mouse model of excision wounding. Moreover, wounds also closed faster in PARP-1 knockout mice as compared with wild-type littermates. Immunofluorescent staining for poly(ADP-ribose) (PAR) indicated increased PAR synthesis in scattered cells of the wound bed. Expression of interleukin (IL)-6, tumor necrosis factor (TNF)-α, inducible nitric oxide synthase and matrix metalloproteinase-9 was lower in the wounds of PARP-1 knockout mice as compared with control, and expression of IL-1β, cyclooxygenase-2, TIMP-1 and -2 also were affected. The level of nitrotyrosine (a marker of nitrating stress) was lower in the wounds of PARP-1 knockout animals as compared with controls. In vitro
scratch assays revealed significantly faster migration of keratinocytes treated with 3-aminobenzamide or PJ34 as compared with control cells. These data suggest that PARylation by PARP-1 slows down the wound healing process by increasing the production of inflammatory mediators and nitrating stress and by slowing the migration of keratinocytes.

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Supplemental Data
Posted by Sheila Platt on Aug 26, 2014 9:12 AM CDT
Daolin Tang, Rui Kang, Bennett Van Houten, Herbert J Zeh, Timothy R Billiar, and Michael T Lotze

High mobility group box 1 (HMGB1) is an evolutionarily ancient protein that is present in one form or another in all eukaryotes. It fundamentally resides in the nucleus but translocates to the cytosol with stress and is subsequently released into the extracellular space. HMGB1 global knockout mice exhibit lethal hypoglycemia, whereas tissues and cells from conditional knockout or knockin mice are born alive without apparent significant functional deficit. An aberrant response to targeted stress in the liver, pancreas, heart or myeloid cells is consistent with a protective role for HMGB1 in sustaining nuclear homeostasis and enabling other stress responses, including autophagy. Under some conditions, HMGB1 is not required for liver and heart function. Many challenges remain with respect to understanding the multiple roles of HMGB1 in health and disease.

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Posted by Sheila Platt on Aug 19, 2014 12:21 PM CDT
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