Project description:Neurofibromatosis type 1 (NF1) is a multi-system disease caused by mutations in the NF1 gene encoding a Ras-GAP protein, neurofibromin, which negatively regulates Ras signalling. Besides neuroectodermal malformations and tumours, the skeletal system is often affected (e.g. scoliosis and long bone dysplasia), demonstrating the importance of neurofibromin for development and maintenance of the musculoskeletal system. Here we focus on the role of neurofibromin in skeletal muscle development. Nf1 gene inactivation in the early limb bud mesenchyme using Prx1-cre (Nf1Prx1) resulted in muscle dystrophy characterised by fibrosis, reduced number of muscle fibres, and reduced muscle force. To gain insight into the molecular changes of the observed muscle dystrophy and fibrosis and to compare these with other known muscle dystrophies, we performed transcriptional profiling of the entire triceps muscles of threemonth-old wild type (wt) and mutant animals using Affymetrix high-density microrrays. We analyzed triceps muscles from 4 three-month-old wt controls and 4 three-month-old Nf1Prx1 mice using the Affymetrix Mouse Gene 1.0 ST platform. Array data was processed by the Affymetrix Exon Array Computational Tool. RNA isolated from each animal was hybridized to a separate microarray.
Project description:Neurofibromatosis type 1 (NF1) is a multi-system disease caused by mutations in the NF1 gene encoding a Ras-GAP protein, neurofibromin, which negatively regulates Ras signalling. Besides neuroectodermal malformations and tumours, the skeletal system is often affected (e.g. scoliosis and long bone dysplasia), demonstrating the importance of neurofibromin for development and maintenance of the musculoskeletal system. Here we focus on the role of neurofibromin in skeletal muscle development. Nf1 gene inactivation in the early limb bud mesenchyme using Prx1-cre (Nf1Prx1) resulted in muscle dystrophy characterised by fibrosis, reduced number of muscle fibres, and reduced muscle force. To gain insight into the molecular changes of the observed muscle dystrophy and fibrosis and to compare these with other known muscle dystrophies, we performed transcriptional profiling of the entire triceps muscles of threemonth-old wild type (wt) and mutant animals using Affymetrix high-density microrrays.
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:Purpose: To study Nf1 regulated pathways in controlling juvenile satellite cells quiescence induction. Methods: We sequenced total mRNAs isolated from juvenile satellite cells FACS sorted from postnatal day 7 Control (Nf1flox/+ Myf5Cre+) and KO (Nf1flox/flox Myf5Cre+) mouse hindlimb skeletal muscle. Results: Our study suggests that Nf1 is required for maintaining the balance between quiescence induction and amplification / differentiation in the postnatal MP pool. Conclusions: The tumor suppressor Nf1 maintains the myogenic progenitor (MP) pool during postnatal muscle development.
Project description:Background Neurofibromatosis type 1 (NF1) is a multi-organ disease caused by mutations in Neurofibromin (NF1). Amongst other features, NF1 patients frequently show reduced muscle mass and strength, impairing patients’ mobility and increasing the risk of fall. The role of Nf1 in muscle and the cause for the NF1-associated myopathy is mostly unknown. Methods To dissect the function of Nf1 in muscle, we created muscle-specific knockout mouse models for Nf1, inactivating Nf1 in the prenatal myogenic lineage either under the Lbx1 promoter or under the Myf5 promoter. Mice were analyzed during pre-and postnatal myogenesis and muscle growth. Results Nf1Lbx1 and Nf1Myf5 animals showed only mild defects in prenatal myogenesis. Nf1Lbx1 animals were perinatally lethal, while Nf1Myf5 animals survived up to approx. 25 weeks. Nf1Myf5 animals showed decreased postnatal growth, reduced muscle size, and fast fiber atrophy. Proteome and transcriptome analysis of muscle tissue indicated decreased protein synthesis and increased proteasomal degradation, and decreased glycolytic and increased oxidative activity in muscle tissue. Real-time respirometry demonstrated enhanced oxidative metabolism in Nf1Myf5 muscles concomitant to a fiber type shift from type 2B to type 2A and type 1. Nf1Myf5 muscles showed hallmarks of mild oxidative stress and increased activation of AMPK indicating an energy deficit, increased expression of atrogenes and decreased activation of mTORC1. Proteome and transcriptome analysis indicated that oxidative fibers mainly relied on fatty acid catabolism. Inline, Nf1Myf5 animals showed a drastic reduction of white, but not brown, adipose tissue. Conclusions Our results demonstrate a cell-autonomous role for Nf1 in myogenic cells during postnatal muscle growth required for metabolic and proteostatic homeostasis. Furthermore, Nf1 deficiency in muscle leads to cross-tissue communication and mobilization of lipid reserves.
Project description:Neurofibromatosis type 1 (NF1) is a neurogenetic disorder caused by loss of function mutations in the gene neurofibromin 1 (NF1). NF1 encodes neurofibromin, a multifunctional tumor suppressing protein that regulates Ras, cAMP, and dopamine signaling. NF1 predisposes patients to a wide range of symptoms, including peripheral nerve tumors, brain tumors, and cognitive dysfunction. Despite considerable work using animal models to investigate the role of neurofibromin in behavior, translating research into treatment for NF1-associated cognitive dysfunction has not yet been successful. Here, we provide evidence that Cxcr4 chemokine receptor signaling is a regulator of habituation learning and modulator of cAMP-PKA signaling in nf1 mutant larval zebrafish. Combining a small-molecule drug screen and RNAseq analysis, we show that cxcr4b expression is increased in nf1 mutants and that pharmacological inhibition of Cxcr4 with AMD3100 (Plerixafor) improves habituation learning. We further demonstrate that Plerixafor activates cAMP-PKA pathway signaling but has limited effects on Ras-Raf-MEK-ERK pathway signaling in the nf1 mutant brain. CXCR4 was previously identified as a potential therapeutic target for neurofibromin-deficient tumorigenesis. Our results suggest that Cxcr4 signaling also regulates neurofibromin-dependent cognitive function.