Effect of chronic treatment with bovine recombinant growth hormone on cardiac dysfunction and lesion progression in UM-X7.1 cardiomyopathic hamsters

In view of the potentially beneficial effect of GH on ventricular function of humans suffering from idiopathic dilated cardiomyopathy, we undertook a study to evaluate the optimal time to initiate treatment with GH and its duration in UM-X7.1 cardiomyopathic hamsters (CMH). GH (1 mg/kg.d) therapy was initiated either in the early or late (30 and 160 d old, respectively) phases of the disease and continued until death at 240 d of age. Age- and sex-matched Golden Syrian hamsters (GSH) were used as controls. Basal IGF-1 levels in serum were reduced by nearly half in CMH compared with GSH but were increased within a physiological range in male hamsters. In contrast, female hamsters presented elevated basal serum IGF-1 levels that were not further elevated by GH administration, as reported in experimental models and humans. Accordingly, the present study will focus on the effects of GH therapy on cardiac performance in male hamsters. GH did not improve ventricular function when starting at a late stage of the disease compared with CMH controls. Maximum rate of left ventricular pressure development decreased by approximately 64% in CMH treated early with recombinant bovine GH. Ventricular dysfunction was associated with morphologic indices of hypertrophy, ventricular dilatation, and extensive fibrosis. Mortality was strikingly increased in GH-treated CMH for 210 d (four males and eight females), as opposed to four females (and no male) in the vehicle-treated group. These results suggest that chronic treatment with recombinant bovine GH in CMH, starting at an early stage of lesion development, is associated with a reduced cardiac performance at the terminal stage of the disease.     

Chronic AMPK activation evokes the slow, oxidative myogenic program and triggers beneficial adaptations in mdx mouse skeletal muscle

A therapeutic approach for Duchenne muscular dystrophy (DMD) is to up-regulate utrophin in skeletal muscle in an effort to compensate for the lack of dystrophin. We previously hypothesized that promotion of the slow, oxidative myogenic program, which triggers utrophin up-regulation, can attenuate the dystrophic pathology in mdx animals. Since treatment of healthy mice with the AMP-activated protein kinase (AMPK) activator 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) enhances oxidative capacity and elicits a fast-to-slow fiber-type transition, we evaluated the effects of chronic AMPK stimulation on skeletal muscle phenotype and utrophin expression in mdx mice. Daily AICAR administration (500 mg/kg/day, 30 days) of 5-7-week-old mdx animals induced an elevation in mitochondrial cytochrome c oxidase enzyme activity, an increase in myosin heavy-chain type IIa-positive fibers and slower twitch contraction kinetics in the fast, glycolytic extensor digitorum longus muscle. Utrophin expression was significantly enhanced in response to AICAR, which occurred coincident with an elevated β-dystroglycan expression along the sarcolemma. These adaptations were associated with an increase in sarcolemmal structural integrity under basal conditions, as well as during damaging eccentric contractions ex vivo. Notably, peroxisome proliferator-activated receptor γ co-activator-1α (PGC-1α) and silent information regulator two ortholog 1 protein contents were significantly higher in muscle from mdx mice compared with wild-type littermates and AICAR further increased PGC-1α expression. Our data show that AICAR-evoked muscle plasticity results in beneficial phenotypic adaptations in mdx mice and suggest that the contextually novel application of this compound for muscular dystrophy warrants further study.     

Essential Role of Osteopontin in Smoking-Related Interstitial Lung Diseases

Smoking-related interstitial lung diseases are characterized by the accumulation of macrophages and Langerhans cells, and fibrotic remodeling, which are linked to osteopontin (OPN) expression. Therefore, OPN levels were investigated in bronchoalveolar lavage (BAL) cells in 11 patients with pulmonary Langerhans cell histiocytosis (PLCH), 15 patients with desquamative interstitial pneumonitis (DIP), 10 patients with idiopathic pulmonary fibrosis, 5 patients with sarcoidosis, 13 otherwise healthy smokers, and 19 non-smoking controls. Furthermore, OPN overexpression was examined in rat lungs using adenoviral gene transfer. We found that BAL cells from patients with either PLCH or DIP spontaneously produced abundant amounts of OPN. BAL cells from healthy smokers produced 15-fold less OPN, and those cells from non-smoking healthy volunteers produced no OPN. BAL cells from patients with either idiopathic pulmonary fibrosis or sarcoidosis produced significantly less OPN, as compared with patients with PLCH. These data were confirmed by immunochemistry. Nicotine stimulation increased production of both OPN and granulocyte-macrophage colony stimulating factor by alveolar macrophages from smokers. Nicotinic acetylcholine receptor expression resembled the pattern of spontaneous OPN production and was dramatically increased in both PLCH and DIP. OPN overexpression in rat lungs induced lesions similar to PLCH with marked alveolar and interstitial accumulation of Langerhans cells. Our findings suggest a pathogenetic role of increased OPN production in both PLCH and DIP by promoting the accumulation of macrophages and Langerhans cells.Cigarette smoke is linked to a variety of lung diseases including chronic obstructive pulmonary disease, lung cancer, and interstitial lung diseases. Respiratory bronchiolar interstitial lung disease, desquamative interstitial pneumonitis (DIP), and pulmonary Langerhans cell histiocytosis (PLCH) belong to the group of smoking-related interstitial lung diseases.^1,2,3 Cigarette smoke is a complex mixture of more than 4000 compounds and is known to cause systemic and pulmonary effects.⁴ However, the underlying mechanisms as to how cigarette smoking leads to the changes observed in smoking-related interstitial lung diseases are largely unknown.^1,2,3Cigarette smoke induces inflammation, oxidative stress, and tissue injury, and has an important effect on the number, distribution, and activation state of macrophages and Langerhans cells.^5,6 There is a strong epidemiological link between PLCH and smoking. PLCH is characterized by the accumulation of activated Langerhans cells originating from the distal bronchiole walls.^1,2,3,7 The accumulations of Langerhans cells are poorly demarcated and extend to the adjacent alveoli, which often contain an abundance of pigmented macrophages. These areas show morphological changes similar to DIP.^7,8 In DIP, the predominant feature is the accumulation of alveolar macrophages, densely filling the alveolar lumen, combined with moderate fibrotic interstitial remodeling.^1,2As measured by bronchoalveolar lavage (BAL) in healthy individuals, cigarette smoking induces a 5- to 10-fold increase in alveolar macrophages in a dose-response curve.^9,10,11 It was shown that concentrations of granulocyte-macrophage colony stimulating factor (GMCSF) in patients with PLCH are increased,¹² but the mechanisms that lead to the expansion of the pulmonary macrophage pool and fibrosis in smokers are poorly understood.^1,2,3 Based on the findings of a microarray study, Woodruff et al¹³ have recently proposed that alveolar macrophages from smokers exhibit a distinctive macrophage activation state that is accompanied by increased OPN expression. Osteopontin is a glycoprotein found in the extracellular matrix of bone.¹⁴ However, multiple studies have reported cytokine properties of OPN in cell-mediated immunity.¹⁴ Further, OPN exhibits a strong chemotactic activity for macrophages, monocytes, Langerhans cells, and dendritic cells.^15,16,17In the context of these findings we speculated that OPN might be involved in the pathogenesis of smoking-related lung interstitial diseases. We found abundant OPN production by alveolar macrophages from patients with PLCH and DIP. Alveolar macrophages from both healthy smokers and patients with DIP and PLCH show up-regulated nicotine receptor expression as a sign of chronic nicotine stimulation. Further, nicotine directly induced OPN and GMCSF in alveolar macrophages. Our data provides evidence for a role of osteopontin in the pathogenesis of smoking- related interstitial lung diseases.     

TRF1 is degraded by ubiquitin-mediated proteolysis after release from telomeres

Mammalian telomeres are coated by the sequence-specific, DNA-binding protein, TRF1, a negative regulator of telomere length. Previous results showed that ADP-ribosylation of TRF1 by tankyrase 1 released TRF1 from telomeres and promoted telomere elongation. We now show that loss of TRF1 from telomeres results in ubiquitination and degradation of TRF1 by the proteasome and that degradation is required to keep TRF1 off telomeres. Ubiquitination of TRF1 is regulated by its telomere-binding status; only the telomere-unbound form of TRF1 is ubiquitinated. Our findings suggest a novel mechanism of sequential post translational modification of TRF1 (ADP-ribosylation and ubiquitination) for regulating access of telomerase to telomeres.     

High-Resolution Melting Analysis as a Sensitive Prescreening Diagnostic Tool to Detect KRAS , BRAF , PIK3CA , and AKT1 Mutations in Formalin-Fixed, Paraffin-Embedded Tissues

Context .-As the availability of targeted therapies for several tumor types increases, the need for rapid and sensitive mutation screening is growing. KRAS mutations constitutively activate the RAS/RAF/mitogen-activated protein kinase (MAPK) pathway and therefore play an important role in anti-epidermal growth factor receptor therapy for patients with colorectal cancers. Mutationally activated PIK3CA and AKT1 genes are promising therapeutic targets in breast cancer. In 60% to 70% of malignant melanomas, a mutation in BRAF can be found. Thus, the blocking of the oncogenic signaling induced by this mutation is now used as treatment approach. Objective .-To establish high-resolution melting assays for routinely used predictive analyses of KRAS , AKT1 , PIK3CA , and BRAF mutations. Design .-High-resolution melting assays were developed by using specifically designed primers and genomic DNA isolated either from cell lines or formalin-fixed paraffin-embedded tissues, oligonucleotides, or plasmids. Melting curve analyses were performed on the LightCyler platform and mutation analyses were additionally confirmed by Sanger sequencing. Results .-We developed high-resolution melting assays by using genomic DNA containing the desired mutation, which enabled us to detect percentages of mutated DNA (3.1% to 12.5%) mixed in a wild-type background. Assays were evaluated by hybridization probes and/or Sanger sequencing to exclude pseudogene amplification. The high-resolution melting assays were validated with genomic DNA from different tumor entities. The concordance between Sanger sequencing and high-resolution melting was 99% for KRAS exon 2 and PIK3CA exon 20 and 100% for the remaining assays. Conclusions .-High-resolution melting provides a valid and powerful tool for detecting genomic mutations efficiently.     

Evidence for a role of connexin 43 in trigeminal pain using RNA interference in vivo

The importance of glial cells in the generation and maintenance of neuropathic pain is becoming widely accepted. We examined the role of glial-specific gap junctions in nociception in the rat trigeminal ganglion in nerve-injured and -uninjured states. The connexin 43 (Cx43) gap-junction subunit was found to be confined to the satellite glial cells (SGCs) that tightly envelop primary sensory neurons in the trigeminal ganglion and we therefore used Cx43 RNA interference (RNAi) to alter gap-junction function in SGCs. Using behavioral evaluation, together with immunocytochemical and Western blot monitoring, we show that Cx43 increased in the trigeminal ganglion in rats with a chronic constriction injury (CCI) of the infraorbital nerve. Reducing Cx43 expression using RNAi in CCI rats reduced painlike behavior, whereas in non-CCI rats, reducing Cx43 expression increased painlike behavior. The degree of painlike behavior in CCI rats and intact, Cx43-silenced rats was similar. Our results support previous suggestions that increases in glial gap junctions after nerve injury increases nociceptive behavior but paradoxically the reduction of gap junctions in normal ganglia also increases nociceptive behavior, possibly a reflection of the multiple functions performed by glia.     

Reliable detection and quantitation of viral nucleic acids in oral fluid: Liquid phase-based sample collection in conjunction with automated and standardized molecular assays

Oral fluid has been used widely as sample matrix for the detection and quantitation of viral nucleic acids. However, in the vast majority of previous studies, various methods for collection of oral fluid and molecular assays lacking automation and standardization were used. In this study, a new standardized liquid phase-based saliva collection system was employed followed by a fully automated viral nucleic acid extraction and real-time PCR using commercially available in vitro diagnostics (IVD)/Conformité Européene (CE) labeled molecular assays. When the lower limit of detection of herpes simplex virus (HSV)-1/2 DNA, varicella zoster virus (VZV) DNA, and hepatitis C virus (HCV) RNA in spiked oral fluid was tested, the results were found to be comparable to those with defined sample materials recommended by the assay manufacturers. When clinical specimens were investigated, 21 of 25 (84%) oral fluids obtained from patients with clinically apparent herpetic lesions tested positive for HSV DNA, 7 of 10 (70%) oral fluids obtained from patients with Ramsay Hunt Syndrome tested positive for VZV DNA, and 19 of 40 (48%) oral fluids collected from patients with chronic HCV infection tested positive for HCV RNA. The automated extraction instruments completed all extractions without malfunction and no inhibitions were observed throughout the entire study. Liquid phase-based saliva collection in conjunction with automated and standardized commercially available molecular assays allows reliable quantitation of viral nucleic acids in oral fluid samples and may contribute to improved comparable and interpretable test results.     

Early effector maturation of naïve human CD8+ T cells requires mitochondrial biogenesis

The role of mitochondrial biogenesis during naïve to effector differentiation of CD8⁺ T cells remains ill explored. In this study, we describe a critical role for early mitochondrial biogenesis in supporting cytokine production of nascent activated human naïve CD8⁺ T cells. Specifically, we found that prior to the first round of cell division activated naïve CD8⁺ T cells rapidly increase mitochondrial mass, mitochondrial respiration, and mitochondrial reactive oxygen species (mROS) generation, which were all inter‐linked and important for CD8⁺ T cell effector maturation. Inhibition of early mitochondrial biogenesis diminished mROS dependent IL‐2 production – as well as subsequent IL‐2 dependent TNF, IFN‐γ, perforin, and granzyme B production. Together, these findings point to the importance of mitochondrial biogenesis during early effector maturation of CD8⁺ T cells.