Project description:BackgroundCancer is primarily a disease of high age in humans, yet most mouse studies on cancer cachexia are conducted using young adolescent mice. Given that metabolism and muscle function change with age, we hypothesized that aging may affect cachexia progression in mouse models.MethodsWe compare tumor and cachexia development in young and old mice of three different strains (C57BL/6J, C57BL/6N, BALB/c) and with two different tumor cell lines (Lewis Lung Cancer, Colon26). Tumor size, body and organ weights, fiber cross-sectional area, circulating cachexia biomarkers, and molecular markers of muscle atrophy and adipose tissue wasting are shown. We correlate inflammatory markers and body weight dependent on age in patients with cancer.ResultsWe note fundamental differences between mouse strains. Aging aggravates weight loss in LLC-injected C57BL/6J mice, drives it in C57BL/6N mice, and does not influence weight loss in C26-injected BALB/c mice. Glucose tolerance is unchanged in cachectic young and old mice. The stress marker GDF15 is elevated in cachectic BALB/c mice independent of age and increased in old C57BL/6N and J mice. Inflammatory markers correlate significantly with weight loss only in young mice and patients.ConclusionsAging affects cachexia development and progression in mice in a strain-dependent manner and influences the inflammatory profile in both mice and patients. Age is an important factor to consider for future cachexia studies.
Project description:BackgroundMuscle wasting is a profound side effect of advanced cancer. Cancer-induced cachexia decreases patient quality of life and is associated with poor patient survival. Currently, no clinical therapies exist to treat cancer-induced muscle wasting. Although cancers commonly associated with cachexia occur in older individuals, the standard animal models used to elucidate the causes of cachexia rely on juvenile mice.MethodsIn an effort to better model human cancer cachexia, we determined whether cachectic features seen in young mice could be achieved in adult, pre-sarcopenic mice following colon 26 (C-26) tumor cell inoculation.ResultsBoth young and adult mice developed similar-sized tumors and progressed to cachexia with similar kinetics, as evidenced by losses in body mass, and adipose and skeletal muscle tissues. Proteolytic signaling, including proteasome and autophagy genes, was also increased in muscles from both young and adult tumor-bearing animals. Furthermore, tumor-associated muscle damage and activation of Pax7 progenitor cells was induced in both young and adult mice.ConclusionsAlthough cancer cachexia generally occurs in older individuals, these data suggest that the phenotype and underlying mechanisms can be effectively modeled using the currently accepted protocol in juvenile mice.
Project description:Bile acids exert diverse actions on host metabolism and immunity through bile acid-activated receptors, including Takeda G protein-coupled receptor 5 (TGR5). We have recently evidenced an alteration in bile acids in cancer cachexia, an inflammatory and metabolic syndrome contributing to cancer death. This current study aims to further explore the links emerging between bile acids and cancer cachexia. First, we showed that bile flow is reduced in cachectic mice. Next, comparing mice inoculated with cachexia-inducing and with non-cachexia-inducing C26 colon carcinoma cells, we demonstrated that alterations in the bile acid pathways and profile are directly associated with cachexia. Finally, we performed an interventional study using ursodeoxycholic acid (UDCA), a compound commonly used in hepatobiliary disorders, to induce bile acid secretion and decrease inflammation. We found that UDCA does not improve hepatic inflammation and worsens muscle atrophy in cachectic mice. This exacerbation of the cachectic phenotype upon UDCA was accompanied by a decreased TGR5 activity, suggesting that TGR5 agonists, known to reduce inflammation in several pathological conditions, could potentially counteract cachectic features. This work brings to light major evidence sustaining the emerging links between bile acids and cancer cachexia and reinforces the interest in studying bile acid-activated receptors in this context.
Project description:Sympathetic nervous system development depends upon many factors that mediate neuron migration, differentiation and survival. Target tissue-derived nerve growth factor (NGF) signaling-induced gene expression is required for survival, differentiation and target tissue innervation of post-migratory sympathetic neurons. However, the transcriptional regulatory mechanisms mediated by NGF signaling are very poorly defined. Here, we identify Egr3, a member of the early growth response (Egr) family of transcriptional regulators, as having an important role in sympathetic nervous system development. Egr3 is regulated by NGF signaling and it is expressed in sympathetic neurons during development when they depend upon NGF for survival and target tissue innervation. Egr3-deficient mice have severe sympathetic target tissue innervation abnormalities and profound physiological dysautonomia. Unlike NGF, which is essential for sympathetic neuron survival and for axon branching within target tissues, Egr3 is required for normal terminal axon extension and branching, but not for neuron survival. The results indicate that Egr3 is a novel NGF signaling effector that regulates sympathetic neuron gene expression required for normal target tissue innervation and function. Egr3-deficient mice have a phenotype that is remarkably similar to humans with sympathetic nervous system disease, raising the possibility that it may have a role in some forms of human dysautonomia, most of which have no known cause.
Project description:Neuroblastoma is an embryonal neoplasm that remains of dramatic prognosis in its aggressive forms. Activating mutations of the ALK tyrosine kinase receptor have been identified in sporadic and familial cases of this cancer. We generated knock-in mice carrying an F1178L Alk mutation corresponding to the ALK F1174L mutation observed in neuroblastoma patients We used microarrays to detail the global programme of gene expression underlying the impact of ALK F1178L mutation on sympathetic nervous system ganglia We selected sympathetic nervous system ganglia (superior cervical and stellate ganglia) for RNA extraction and hybridization on Affymetrix microarrays. We profiled a total number of 12 Po (4 Wt; 4 Hz; 4 Ho) and 5 P18 (3 Wt; 2 Hz)
Project description:Neuroblastoma is an embryonal neoplasm that remains of dramatic prognosis in its aggressive forms. Activating mutations of the ALK tyrosine kinase receptor have been identified in sporadic and familial cases of this cancer. We generated knock-in mice carrying an F1178L Alk mutation corresponding to the ALK F1174L mutation observed in neuroblastoma patients We used microarrays to detail the global programme of gene expression underlying the impact of ALK F1178L mutation on sympathetic nervous system ganglia
Project description:: Patients with malignant tumors frequently suffer during disease progression from a syndrome referred to as cancer cachexia (CaCax): CaCax includes skeletal muscle atrophy and weakness, loss of bodyweight, and fat tissues. Currently, there are no FDA (Food and Drug Administration) approved treatments available for CaCax. Here, we studied skeletal muscle atrophy and dysfunction in a murine CaCax model by injecting B16F10 melanoma cells into mouse thighs and followed mice during melanoma outgrowth. Skeletal muscles developed progressive weakness as detected by wire hang tests (WHTs) during days 13-23. Individual muscles analyzed at day 24 had atrophy, mitochondrial dysfunction, augmented metabolic reactive oxygen species (ROS) stress, and a catabolically activated ubiquitin proteasome system (UPS), including upregulated MuRF1. Accordingly, we tested as an experimental intervention of recently identified small molecules, Myomed-205 and -946, that inhibit MuRF1 activity and MuRF1/MuRF2 expression. Results indicate that MuRF1 inhibitor fed attenuated induction of MuRF1 in tumor stressed muscles. In addition, the compounds augmented muscle performance in WHTs and attenuated muscle weight loss. Myomed-205 and -946 also rescued citrate synthase and complex-1 activities in tumor-stressed muscles, possibly suggesting that mitochondrial-metabolic and muscle wasting effects in this CaCax model are mechanistically connected. Inhibition of MuRF1 during tumor cachexia may represent a suitable strategy to attenuate skeletal muscle atrophy and dysfunction.
Project description:The peripheral nervous system modulates bone repair under physiological and pathophysiological conditions. Previously, we reported an essential role for sensory neuropeptide substance P (SP) and sympathetic nerve fibers (SNF) for proper fracture healing and bone structure in a murine tibial fracture model. A similar distortion of bone microarchitecture has been described for mice lacking the sensory neuropeptide α-calcitonin gene-related peptide (α-CGRP). Here, we hypothesize that loss of SP, α-CGRP, and SNF modulates inflammatory and pain-related processes and also affects bone regeneration during fracture healing under postmenopausal conditions. Intramedullary fixed femoral fractures were set to 28 days after bilateral ovariectomy (OVX) in female wild type (WT), SP-, α-CGRP-deficient, and sympathectomized (SYX) mice. Locomotion, paw withdrawal threshold, fracture callus maturation and numbers of TRAP-, CD4-, CD8-, F4/80-, iNos-, and Arg1-positive cells within the callus were analyzed. Nightly locomotion was reduced in unfractured SP-deficient and SYX mice after fracture. Resistance to pressure was increased for the fractured leg in SP-deficient mice during the later stages of fracture healing, but was decreased in α-CGRP-deficient mice. Hypertrophic cartilage area was increased nine days after fracture in SP-deficient mice. Bony callus maturation was delayed in SYX mice during the later healing stages. In addition, the number of CD 4-positive cells was reduced after five days and the number of CD 8-positive cells was additionally reduced after 21 days in SYX mice. The number of Arg1-positive M2 macrophages was higher in α-CGRP-deficient mice five days after fracture. The alkaline phosphatase level was increased in SYX mice 16 days after fracture. Absence of α-CGRP appears to promote M2 macrophage polarization and reduces the pain threshold, but has no effect on callus tissue maturation. Absence of SP reduces locomotion, increases the pain-threshold, and accelerates hypertrophic callus tissue remodeling. Destruction of SNF reduces locomotion after fracture and influences bony callus tissue remodeling during the later stages of fracture repair, whereas pain-related processes are not affected.
Project description:Social instability can adversely affect endocrine, immune and health outcomes, and recent evidence suggests that the sympathetic nervous system (SNS) might mediate these effects. We conducted two studies with adult male rhesus monkeys (Macaca mulatta) to understand how social conditions affect measures of SNS activity and immune function. In Experiment 1, animals were socialized in stable social conditions, then were switched to unstable (stressful) social conditions, then were returned to stable conditions. Analysis revealed quadratic effects for measures of behaviour, urinary metabolites of epinephrine and norepinephrine, and expression of immune response genes: as expected, social instability adversely impacted most measures, and the effects remediated upon re-imposition of stable conditions. Cortisol levels were unaffected. In Experiment 2, we used the sympathomimetic drug methamphetamine to challenge the SNS; animals also underwent socialization in stable or unstable groups. Surprisingly, while methamphetamine elevated plasma catecholamines, responses in lymph nodes tracked the social, and not the drug, condition: social instability upregulated the density of SNS fibres in lymph nodes and downregulated Type I interferon gene expression. Together, these results indicate that the SNS is extremely sensitive to social conditions; full understanding of the adverse effects of social instability on health should therefore incorporate measures of this health-relevant system.
Project description:Several articles have dealt with the importance and mechanisms of the sympathetic nervous system alterations in experimental animal models of hypertension. This review addresses the role of the sympathetic nervous system in the pathophysiology and therapy of human hypertension. We first discuss the strengths and limitations of various techniques for assessing the sympathetic nervous system in humans, with a focus on heart rate, plasma norepinephrine, microneurographic recording of sympathetic nerve traffic, and measurements of radiolabeled norepinephrine spillover. We then examine the evidence supporting the importance of neuroadrenergic factors as promoters and amplifiers of human hypertension. We expand on the role of the sympathetic nervous system in 2 increasingly common forms of secondary hypertension, namely hypertension associated with obesity and with renal disease. With this background, we examine interventions of sympathetic deactivation as a mode of antihypertensive treatment. Particular emphasis is given to the background and results of recent therapeutic approaches based on carotid baroreceptor stimulation and radiofrequency ablation of the renal nerves.