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Molecular Medicine 2014

Articles from this Volume

Posted by Sheila Platt on Apr 14, 2015 9:24 AM CDT
Posted by Sheila Platt on Apr 14, 2015 9:22 AM CDT
HaiJiao Zhang, Lilia Goudeva, Stephan Immenschuh, Axel Schambach, Julia Skokowa, Britta Eiz-Vesper, Rainer Blasczyk, and Constança Figueiredo

Granulocyte colony-stimulating factor (G-CSF) is a major regulator of granulopoiesis on engagement with the G-CSF receptor (G-CSFR). The truncated, alternatively spliced, class IV G-CSFR (G-CSFRIV) has been associated with defective differentiation and relapse risk in pediatric acute myeloid leukemia (AML) patients. However, the detailed biological properties of G-CSFRIV in human CD34+ hematopoietic stem and progenitor cells (HSPCs) and the potential leukemogenic mechanism of this receptor remain poorly understood. In the present study, we observed that G-CSFRIV–overexpressing (G-CSFRIV+) HSPCs demonstrated an enhanced proliferative and survival capacity on G-CSF stimulation. Cell cycle analyses showed a higher frequency of G-CSFRIV+ cells in the S and G2/M phase. Also, apoptosis rates were significantly lower in G-CSFRIV+ HSPCs. These findings were shown to be associated with a sustained Stat5 activation and elevated miR-155 expression. In addition, G-CSF showed to further induce G-CSFRIV and miR-155 expression of peripheral blood mononuclear cells isolated from AML patients. A Stat5 pharmacological inhibitor or ribonucleic acid (RNA) interference–mediated silencing of the expression of miR-155 abrogated the aberrant proliferative capacity of the G-CSFRIV+ HSPCs. Hence, the dysregulation of Stat5/miR-155 pathway in the G-CSFRIV+ HSPCs supports their leukemogenic potential. Specific miRNA silencing or the inhibition of Stat5-associated pathways might contribute to preventing the risk of leukemogenesis in G-CSFRIV+ HSPCs. This study may promote the development of a personalized effective antileukemia therapy, in particular for the patients exhibiting higher expression levels of G-CSFRIV, and further highlights the necessity of prescreening the patients for G-CSFR isoforms expression patterns before G-CSF administration.

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Posted by Sheila Platt on Apr 9, 2015 2:17 PM CDT
Leona Mawhinney, Michelle E Armstrong, Ciaran O’Reilly, Richard Bucala, Lin Leng, Gunter Fingerle-Rowson, Darren Fayne, Michael P Keane, Aisling Tynan, Lewena Maher, Gordon Cooke, David Lloyd, Helen Conroy, and Seamas C Donnelly

The cytokine macrophage migration inhibitory factor (MIF) possesses unique tautomerase enzymatic activity, which contributes to the biological functional activity of MIF. In this study, we investigated the effects of blocking the hydrophobic active site of the tautomerase activity of MIF in the pathogenesis of lung cancer. To address this, we initially established a Lewis lung carcinoma (LLC) murine model in Mif-KO and wild-type (WT) mice and compared tumor growth in a knock-in mouse model expressing a mutant MIF lacking enzymatic activity (Mif P1G). Primary tumor growth was significantly attenuated in both Mif-KO and Mif P1G mice compared with WT mice. We subsequently undertook a structure-based, virtual screen to identify putative small molecular weight inhibitors specific for the tautomerase enzymatic active site of MIF. From primary and secondary screens, the inhibitor SCD-19 was identified, which significantly attenuated the tautomerase enzymatic activity of MIF in vitro and in biological functional screens. In the LLC murine model, SCD-19, given intraperitoneally at the time of tumor inoculation, was found to significantly reduce primary tumor volume by 90% (p < 0.001) compared with the control treatment. To better replicate the human disease scenario, SCD-19 was given when the tumor was palpable (at d 7 after tumor inoculation) and, again, treatment was found to significantly reduce tumor volume by 81% (p < 0.001) compared with the control treatment. In this report, we identify a novel inhibitor that blocks the hydrophobic pocket of MIF, which houses its specific tautomerase enzymatic activity, and demonstrate that targeting this unique active site significantly attenuates lung cancer growth in in vitro and in vivo systems.

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Posted by Sheila Platt on Apr 9, 2015 1:46 PM CDT
Lesley-Ann Sutton, Giorgos Papadopoulos, Anastasia Hadzidimitriou, Stavros Papadopoulos, Efterpi Kostareli, Richard Rosenquist, Dimitrios Tzovaras, and Kostas Stamatopoulos

Patients with chronic lymphocytic leukemia (CLL) assigned to stereotyped subset #4 express highly homologous B-cell receptor immunoglobulin (BcR IG) sequences with intense intraclonal diversification (ID) in the context of ongoing somatic hypermutation (SHM). Their remarkable biological and clinical similarities strongly support derivation from a common ancestor. We here revisited ID in subset #4 CLL to reconstruct their evolutionary history as a community of related clones. To this end, using specialized bioinformatics tools we assessed both IGHV–IGHD–IGHJ rearrangements (n = 511) and IGKV–IGKJ rearrangements (n = 397) derived from eight subset #4 cases. Due to high sequence relatedness, a number of subclonal clusters from different cases lay very close to one another, forming a core from which clusters exhibiting greater variation stemmed. Minor subclones from individual cases were mutated to such an extent that they now resembled the sequences of another patient. Viewing the entire subset #4 data set as a single entity branching through diversification enabled inference of a common sequence representing the putative ancestral BcR IG expressed by their still elusive common progenitor. These results have implications for improved understanding of the ontogeny of CLL subset #4, as well as the design of studies concerning the antigenic specificity of the clonotypic BcR IGs.

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Posted by Sheila Platt on Apr 2, 2015 9:40 AM CDT
Sun Jung Kim, Jordan Goldstein, Kimberly Dorso, Miriam Merad, Lloyd Mayer, James M Crawford, Peter K Gregersen, and Betty Diamond

A single nucleotide polymorphism of PRDM1, the gene encoding Blimp-1, is strongly associated with inflammatory bowel disease.Here, we demonstrate that Blimp-1 in CD103+ dendritic cells (DCs) critically contributes to the regulation of macrophage homeostasis in the colon. Dextran sodium sulfate (DSS)-exposed Blimp-1cko mice with a deletion of Blimp-1 in CD103+ DCs and CD11chi macrophages exhibited severe inflammatory symptoms, pronounced weight loss, high mortality, robust infiltration of neutrophils in epithelial regions of the colon, an increased expression of proinflammatory cytokines and a significant decrease in CD103+ DCs in the colon compared with DSS exposed wild-type (WT) mice. Purified colonic macrophages from Blimp-1cko mice expressed increased levels of matrix metalloproteinase 8, 9 and 12 mRNA. WT macrophages cocultured with colonic DCs but not bone marrow–derived DCs from Blimp-1cko produced increased matrix metalloproteinases in an interleukin (IL)-1β– and IL-6–dependent manner. Treatment of Blimp-1cko mice with anti–IL-1β and anti–IL-6 abrogated the exaggerated clinical response. Overall, these data demonstrate that Blimp-1 expression in DCs can alter an innate inflammatory response by modulating the activation of myeloid cells. This is a novel mechanism of contribution of Blimp-1 for the pathogenesis of inflammatory bowel diseases, implicating another therapeutic target for the development of inflammatory bowel disease.

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Posted by Sheila Platt on Mar 24, 2015 1:42 PM CDT
Chung-Hsien Li, Ming-Hong Lin, Shih-Han Chu, Pang-Hsien Tu, Cheng-Chieh Fang, Chia-Hung Yen, Peir-In Liang, Jason C Huang, Yu-Chia Su, Huey-Kang Sytwu, and Yi-Ming Arthur Chen

Glycine N-methyltransferase (GNMT) is known for its function as a tumor suppressor gene. Since 100% of female Gnmt–/– mice developed hepatocellular carcinoma, we hypothesized that Gnmt–/– mice may have defective immune surveillance. In this study, we examined the immune modulation of GNMT in T-cell responses using experimental autoimmune encephalomyelitis (EAE). The results showed that EAE severity was reduced significantly in Gnmt–/– mice. Pathological examination of the spinal cords revealed that Gnmt–/– mice had significantly lower levels of mononuclear cell infiltration and demyelination than the wild-type mice. In addition, quantitative real-time PCR showed that expression levels of proinflammatory cytokines, including interferon (IFN)-γ and interleukin (IL)-17A, were much lower in the spinal cord of Gnmt–/– than in that of wild-type mice. Accordingly, myelin oligodendrocyte glycoprotein (MOG)- specific T-cell proliferation and induction of T-helper (Th)1 and Th17 cells were markedly suppressed in MOG35–55-induced Gnmt–/– mice. Moreover, the number of regulatory T (Treg) cells was increased significantly in these mice. When the T-cell receptor was stimulated, the proliferative capacity and the activation status of mTOR-associated downstream signaling were decreased significantly in Gnmt–/– CD4+ T cells via an IL-2- and CD25-independent manner. Moreover, GNMT deficiency enhanced the differentiation of Treg cells without affecting the differentiation of Th1 and Th17 cells. Furthermore, the severity of EAE in mice adoptive transferred with GNMT-deficient CD4+ T cells was much milder than in those with wild-type CD4+ T cells. In summary, our findings suggest that GNMT is involved in the pathogenesis of EAE and plays a crucial role in the regulation of CD4+ T-cell functions.

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Posted by Sheila Platt on Mar 24, 2015 1:28 PM CDT
Audrey Courtois, Betty V Nusgens, Roland Hustinx, Gauthier Namur, Pierre Gomez, Helena Kuivaniemi, Jean-Olivier Defraigne, Alain C Colige, and Natzi Sakalihasan

Rupture of abdominal aortic aneurysm (AAA) is a cause of significant mortality and morbidity in aging populations. Uptake of 18-fluorodeoxyglucose (FDG) detected by positron emission tomography (PET) is observed in the wall of 12% of AAA (A+), with most of them being symptomatic. We previously showed that the metabolically active areas displayed adventitial inflammation, medial degeneration and molecular alterations prefacing wall rupture. The aim of this study was to identify new factors predictive of rupture. Transcriptomic analyses were performed in the media and adventitia layers from three types of samples: AAA without FDG uptake (A0) and with FDG uptake (A+), both at the positive spot (A+Pos) and at a paired distant negative site (A+Neg) of the same aneurysm. Follow-up studies included reverse-transcriptase–polymerase chain reaction (RT-PCR), immunohistochemical staining and enzyme-linked immunosorbent assay (ELISA). A large number of genes, including matrix metalloproteinases, collagens and cytokines as well as genes involved in osteochondral development, were differentially expressed in the A+Pos compared with A+Neg. Moreover, a series of genes (notably CCL18) was differentially expressed both in the A+Neg and A+Pos compared with the A0. A significant increase of CCL18 was also found at the protein level in the aortic wall and in peripheral blood of A+ patients compared with A0. In conclusion, new factors, including CCL18, involved in the progression of AAA and, potentially, in their rupture were identified by a genome-wide analysis of PET-positive and -negative human aortic tissue samples. Further work is needed to study their role in AAA destabilization and weakening.

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Posted by Sheila Platt on Mar 24, 2015 12:37 PM CDT
Juan-Pablo Idrovo,Weng-Lang Yang, Asha Jacob, Monowar Aziz, Jeffrey Nicastro, Gene F Coppa, and Ping Wang

Intestinal ischemia and reperfusion (I/R) is encountered in various clinical conditions and contributes to multiorgan failure and mortality as high as 60% to 80%. Intestinal I/R not only injures the intestine, but affects remote organs such as the lung leading to acute lung injury. The development of novel and effective therapies for intestinal I/R are critical for the improvement of patient outcome. AICAR (5-aminoimidazole-4-carboxyamide ribonucleoside) is a cell-permeable compound that has been shown to possess antiinflammatory effects. The objective is to determine that treatment with AICAR attenuates intestinal I/R injury and subsequent acute lung injury (ALI). Male Sprague Dawley rats (275 to 325 g) underwent intestinal I/R injury with blockage of the superior mesenteric artery for 90 min and subsequent reperfusion. At the initiation of reperfusion, vehicle or AICAR (30 mg/kg BW) was given intravenously (IV) for 30 min. At 4 h after reperfusion, blood and tissues were collected for further analyses. Treatment with AICAR significantly decreased the gut damage score and the water content, indicating improvement in histological integrity. The treatment also attenuated tissue injury and proinflammatory cytokines, and reduced bacterial translocation to the gut. AICAR administration after intestinal I/R maintained lung integrity, attenuated neutrophil chemotaxis and infiltration to the lungs and decreased lung levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6. Inflammatory mediators, lung-inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins, were decreased in the lungs and lung apoptosis was significantly reduced after AICAR treatment. These data indicate that AICAR could be developed as an effective and novel therapeutic for intestinal I/R and subsequent ALI.

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Posted by Sheila Platt on Mar 19, 2015 3:22 PM CDT
Niccolò Terrando, Ting Yang, Jae Kyu Ryu,Phillip T Newton, Claudia Monaco, Marc Feldmann, Daqing Ma, Katerina Akassoglou, and Mervyn Maze

Surgery and critical illness often associate with cognitive decline. Surgical trauma or infection can lead independently to learning and memory impairments via similar, but not identical, cellular signaling of the innate immune system that promotes neuroinflammation. In this study we explored the putative synergism between aseptic orthopedic surgery and infection, the latter reproduced by postoperative lipopolysaccharide (LPS) administration. We observed that surgery and LPS augmented systemic inflammation up to postoperative d 3 and this was associated with further neuroinflammation (CD11b and CD68 immunoreactivity) in the hippocampus in mice compared with those receiving surgery or LPS alone. Administration of a selective α7 subtype nicotinic acetylcholine receptor (α7 nAChR) agonist 2 h after LPS significantly improved neuroinflammation and hippocampaldependent memory dysfunction. Modulation of nuclear factor-kappa B (NF-κB) activation in monocytes and regulation of the oxidative stress response through nicotinamide adenine dinucleotide phosphate (NADPH) signaling appear to be key targets in modulating this response. Overall, these results suggest that it may be conceivable to limit and possibly prevent postoperative complications, including cognitive decline and/or infections, through stimulation of the cholinergic antiinflammatory pathway.

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Posted by Sheila Platt on Mar 17, 2015 9:59 AM CDT
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