livers than the other high-fat and the SC animals ( P ≤ 0.05; Table 1 ). The histologic examination (hematoxylin–eosin staining) showed mainly microvesicular fat depositions in the HF-L, HF-O and HF-C livers (Fig. 3 ). No signs of inflammation or
R Buettner, K G Parhofer, M Woenckhaus, C E Wrede, L A Kunz-Schughart, J Schölmerich, and L C Bollheimer
I M Adcock, M Peters, C Gelder, H Shirasaki, C R Brown, and P J Barnes
Substance P has several inflammatory effects on the airways mediated via neurokinin 1 receptors (NK1Rs) and, if released from sensory nerves, may amplify the chronic inflammation seen in asthma. Northern blot analysis of NK1R mRNA in lung showed a 52 ± 10% (s.e.m.; P<0·01) increase in mRNA in the asthmatic lung compared with non-asthmatic control tissue. NK1R mRNA was reduced by 84·5 ± 1·9% after incubation with dexamethasone (1 μm) for 3 h (P<0·01). In contrast, NK2R mRNA was unaltered in asthmatic lungs and dexamethasone treatment had no effect on the level of NK2R mRNA. These results suggest that chronic inflammation in asthma may result in increased NK1R gene expression and that this effect is reversed by glucocorticosteroids.
MK O'Bryan, KL Sebire, O Gerdprasert, MP Hedger, MT Hearn, and DM de Kretser
Using a combination of polymerase chain reaction (PCR) procedures, we have cloned and sequenced the rat activin beta(E) subunit cDNA. The putative protein corresponding to the prepro-activin beta(E) subunit was predicted to comprise 350 amino acids which, when cleaved between amino acid residues 236 and 237, would yield a mature polypeptide of approximately M(r) 12 500 with a predicted pI of 5.1. Two cDNA transcripts for activin beta(E) were identified; these differed by 738 bp in the 3'-untranslated region. Activin beta(E) mRNA transcripts were expressed only in rat liver and lung tissue as assessed by Northern blotting and PCR analysis. Relatively higher levels of both transcripts were found in the liver, whereas the lung contained lower levels that were detectable by PCR only. In situ hybridisation data showed that, within the liver, activin beta(E) mRNA was localised to hepatocytes. In vivo treatment with lipopolysaccharide as a means of activating the immune system and the hepatic acute-phase response resulted in stimulated activin beta(E) mRNA levels, compared with untreated, control rats. This increased expression was accompanied by a preferential increase in the amount of the long activin beta(E) transcript over the shorter transcript. These findings suggested that the two activin beta(E) mRNA transcripts may be products of alternative splicing events or use alternative polyadenylation sites which are differentially regulated during inflammation. These data provide evidence of a role for activin beta(E) in liver function and inflammation in the rat.
JaeSang Ko, Ji-Young Kim, Eun Jig Lee, and Jin Sook Yoon
Inflammation and adipogenesis represent the main pathogenic mechanisms of Graves’ orbitopathy (GO), and oxidative stress is a well-known inducer of GO pathology. Endoplasmic reticulum (ER) stress has been suggested as a major contributor to inflammation and reactive oxygen species (ROS) generation. In this study, we investigated the role of the ER-stress chaperone protein, binding immunoglobulin protein (BiP), in GO pathogenesis. Using primary cultures of orbital fibroblasts from patients with GO, we examined the role of BiP in GO pathogenesis by silencing its expression with small-interfering RNA (siRNA). Inflammatory cytokine expression was analysed by western blotting and enzyme-linked immunosorbent assay. Intracellular ROS levels induced by hydrogen peroxide or cigarette smoke extract were measured by 5-(and 6)-carboxy-20,70-dichlorodihydrofluorescein diacetate staining and flow cytometry. After adipogenic differentiation in BiP siRNA-transfected cells, the cells were stained with Oil Red O, and the levels of adipogenic transcription factors were determined by western blot analysis. BiP mRNA expression levels were significantly higher in GO orbital tissues than in non-GO orbital tissues. Silencing BiP attenuated the expression of pro-inflammatory cytokines (interleukin-6, intercellular adhesion molecule-1, and monocyte chemotactic protein-1) in primary cultured GO orbital fibroblasts. Silencing BiP also reduced ROS generation, hyaluronan production, and adipocyte differentiation. These findings suggest that ER stress is involved in the aetiology of GO and that modulation of ER stress has therapeutic potential for GO.
William Rostene and Julia C Buckingham
Chemokines are small secreted proteins with chemoattractant properties for immune cells. Besides their role in the immune system, chemokines and their receptors may play important roles in the central nervous system. Neurodegenerative disorders that involve neuroinflammation such as multiple sclerosis, stroke, Alzheimer’s disease, Parkinson’s disease and HIV-associated dementia are commonly associated with local upregulation and release of chemokines. However, recent work has established that certain chemokines, constitutively expressed in the brain, exert functions in the brain that are distinct from inflammation. These chemokines regulate neuronal migration during brain development, modulate neuronal activity and play a role in various neurodegenerative diseases, pain and more recently in neuroendocrine functions. All these novel aspects, mainly focused on the chemokine stromal cell-derived factor-1/CXCL12 and its receptor CXCR4, were presented by pioneers in the field during the symposium held at the sixth International Congress of Neuroendocrinology in Pittsburgh, Pennsylvania, USA in June 2006.
Kangmo Lu, Yuehua Zhou, Ken Kaufman, Robert Mott, and Jian-xing Ma
Vascular endothelial growth factor (VEGF) is a potent inflammation, vascular permeability, and angiogenic factor. Variations of the VEGF gene are implicated in the pathogenesis of diabetic retinopathy. Previous studies have shown that Brown Norway (BN) rats have higher retinal VEGF levels and more severe retinal vascular leakage than Sprague–Dawley (SD) rats in response to ischemia and diabetes. To investigate the molecular mechanism of vascular leakage in this animal model, F2 progeny were generated by crossbreeding BN and SD rats. Neonatal rats were exposed to hyperoxia to induce oxygen-induced retinopathy (OIR) models. The F2 rats in response to ischemia have shown a linear distribution of retinal VEGF levels, which is significantly and positively correlated to retinal vascular leakage. We identified a single nucleotide polymorphism (SNP) at upstream stimulating factor-binding site in the VEGF promoter region between BN and SD rats. No differences were found in retinal vascular permeability or VEGF levels between F2 rats with BN, SD, and BN/SD alleles of VEGF SNP. The increased retinal VEGF levels are correlated to ischemia-induced retinal vascular leakage in the OIR rat model. The VEGF mRNA and promoter are not responsible for increased retinal VEGF level and vascular permeability. The up-regulation of VEGF expression activated by a yet to be identified upstream factor or mediator affecting VEGF stability may be associated with a high susceptibility to retinal vascular leakage in BN rats.
WM Cao, K Murao, H Imachi, C Hiramine, H Abe, X Yu, H Dobashi, NC Wong, J Takahara, and T Ishida
The thymus contains many apoptotic cells that arise from the process of positive and negative selection. Both thymic macrophages and thymic nurse cells/nursing thymic epithelial cells (nursing TECs), non-professional phagocytes, recognize and ingest apoptotic cells without inflammation or tissue damage. Previously we reported that human scavenger receptor class B (SR-B1) is involved in recognition of apoptotic thymocytes by nursing TECs. In this study, we examined the expression and role of a phosphatidylserine receptor (PSR). This receptor is believed to participate in the clearance of apoptotic cells. PSR was strongly expressed in nursing TECs. Transforming growth factor-beta augmented the expression of PSR leading to enhanced binding of apoptotic cells to nursing TECs. In nursing TECs, suppressed expression of human SR-B1 with anti-PSR antibody decreased binding of apoptotic thymocytes to nursing TECs. Our results suggest that both PSR and SR-B1 are expressed in nursing TECs and these receptors appear to play a major role in the clearance of apoptotic cells from the thymus.
Kelly E Corcoran, Ashwani Malhotra, Carlos A Molina, and Pranela Rameshwar
The chemokine Stromal-derived factor-1α (SDF-1α) interacts with seven transmembrane (TM) G-protein-coupled receptor (GPR), CXCR4. SDF-1α is linked to inflammation, chemoattraction, cancer metastasis, and hematopoiesis. Tachykinin (Tac1) peptides bind seven transmembrane (TM), GPR and are involved in tumor promotion. SDF-1α regulates Tac1 expression in non-tumorigenic breast cells through a bimodal pattern with repression at high levels through nuclear factor-kappa B (NFκB) activation. This study focuses on the mechanism of activation at low SDF-1α in MCF12A non-tumorigenic breast cells. Reporter gene assays with the 5′ flanking region of Tac1 (exon 1 omitted) and co-transfection with the repressor of cAMP response element (CREB) (ICER), and transfection with the CRE sites mutated, verified critical roles for CRE sites in SDF-1α-mediated Tac1 activation. Western blots and functional assays with specific inhibitors indicated that SDF-1α phosphorylated CREB (P-CREB) via Gαi2-PI3K-protein kinase C (PKC)ζ-p38-extracellular signal-regulated kinase (ERK) and no evidence of cAMP–PKA pathway. This observation is different from previous studies that reported CREB-phosphorylated PKA pathway in the activation of Tac1 in bone marrow stromal cells. This suggests cell specificity in Tac1 expression. In conclusion, this study reports on a non-canonical pathway in Tac1 activation by SDF-1α. This finding is significant, since Tac1 is relevant to breast cancer metastasis, to bone marrow where stromal cells have a significant facilitating function.
Raghunath Chatterjee, Paramita Bhattacharya, Oksana Gavrilova, Kimberly Glass, Jaideep Moitra, Max Myakishev, Stephanie Pack, William Jou, Lionel Feigenbaum, Michael Eckhaus, and Charles Vinson
Adipose-specific inactivation of both AP-1 and CCAAT-enhancer-binding protein (C/EBP) families of B-ZIP transcription factors in transgenic mice causes severe lipoatrophy. To evaluate whether inactivation of only C/EBP members was critical for lipoatrophy, A-C/EBP, a dominant-negative protein that specifically inhibits the DNA binding of the C/EBP members, was expressed in adipose tissue. For the first 2 weeks after birth, aP2-A-C/EBP mice had no white adipose tissue (WAT), drastically reduced brown adipose tissue (BAT), and exhibited marked hepatic steatosis, hyperinsulinemia, and hyperlipidemia. However, WAT appeared during the third week, coinciding with significantly improved metabolic functioning. In adults, BAT remained reduced, causing cold intolerance. At 30 weeks, the aP2-A-C/EBP mice had only 35% reduced WAT, with clear morphological signs of lipodystrophy in subcutaneous fat. Circulating leptin and adiponectin levels were less than the wild-type levels, and these mice exhibited impaired triglyceride clearance. Insulin resistance, glucose intolerance, and reduced free fatty acid release in response to β3-adrenergic agonist suggest improper functioning of the residual WAT. Gene expression analysis of inguinal WAT identified reduced mRNA levels of several enzymes involved in fatty acid synthesis and glucose metabolism that are known C/EBPα transcriptional targets. There were increased levels for genes involved in inflammation and muscle differentiation. However, when dermal fibroblasts from aP2-A-C/EBP mice were differentiated into adipocytes in tissue culture, muscle markers were elevated more than the inflammatory markers. These results demonstrate that the C/EBP family is essential for adipose tissue development during the early postnatal period, the regulation of glucose and lipid homeostasis in adults, and the suppression of the muscle lineage.
Gail P Risbridger, Stuart J Ellem, and Stephen J McPherson
proliferation and prostate carcinogenesis in a manner analogous, yet different, to that of androgens. In addition, estrogens have also been implicated in the development of prostatic inflammation ( Prins et al. 2001 , Bianco et al. 2006