SHP2 brain

Leptin is an adipocytokine that links nutrition to immunity. Previous observation that a genetic polymorphism in the leptin receptor affected susceptibility to Entamoeba histolytica infection led to the hypothesis that leptin signaling has a protective role during intestinal amebic infection. In this study we show that mice lacking the functional leptin receptor developed devastating mucosal destruction after E. histolytica infection. Bone marrow chimera experiments demonstrated that leptin receptor expressed on hematopoietic cells was not sufficient to confer resistance...

Severe stress induces changes in neuronal function that are implicated in stress-related disorders such as depression. The molecular mechanisms underlying the response of the brain to stress remain primarily unknown, however. Signal regulatory protein alpha (SIRPalpha) is an Ig-superfamily protein that undergoes tyrosine phosphorylation and binds the protein tyrosine phosphatase Shp2. Here we show that mice expressing a form of SIRPalpha that lacks most of the cytoplasmic region manifest prolonged immobility (depression-like behavior) in the forced swim (FS) test...

The tyrosine phosphatase SHP2 (PTPN11) regulates cellular proliferation, survival, migration, and differentiation during development. Germline mutations in PTPN11 cause Noonan and LEOPARD syndromes, which have overlapping clinical features. Paradoxically, Noonan syndrome mutations increase SHP2 phosphatase activity, while LEOPARD syndrome mutants are catalytically impaired, raising the possibility that SHP2 has phosphatase-independent roles. By comparing shp2-deficient zebrafish embryos with those injected with mRNA encoding LEOPARD syndrome point mutations, we identify a phosphatase- and Erk-dependent role for Shp2 in neural crest specification and migration...

Gliomas are a diverse group of brain tumors of glial origin. Most are characterized by diffuse infiltrative growth in the surrounding brain. In combination with their refractive nature to chemotherapy this makes it almost impossible to cure patients using combinations of conventional therapeutic strategies. The drastically increased knowledge about the molecular underpinnings of gliomas during the last decade has elicited high expectations for a more rational and effective therapy for these tumors. Most studies on the molecular pathways involved in glioma biology thus far had a strong focus on growth factor receptor protein tyrosine kinase (PTK) and phosphatidylinositol phosphatase signaling pathways...

A gain of function mutation in SHP2, a protein phosphatase encoded by PTPN11, causes Noonan syndrome (NS), which is characterized in part by developmental deficits in both the cardiac and skull fields. Previously, we found that expression of the mutated protein SHP2 Q79R in the heart led to a phenotypic presentation that mimicked some aspects of NS and that this was dependent upon activation of the ERK1/2 pathway. To understand the role that ERK1/2 signaling plays in skull development through signaling in the neural crest, we explored the consequences of Q79R expression in neural crest cells, which contribute to a subset of the bony and cartilaginous structures of the skull...

Shp2 is a non-receptor protein tyrosine phosphatase containing two Src homology 2 (SH2) domains that is implicated in intracellular signaling events controlling cell proliferation, differentiation and migration. To examine the role of Shp2 in brain development, we created mice with Shp2 selectively deleted in neural stem/progenitor cells. Homozygous mutant mice exhibited early postnatal lethality with defects in neural stem cell self-renewal and neuronal/glial cell fate specification. Here we report a critical role of Shp2 in guiding neuronal cell migration in the cerebellum...

Obesity and diabetes, termed "diabesity," are serious health problems that are increasing in frequency. However, the molecular mechanisms and neuronal regulation of these metabolic disorders are not fully understood. We show here that Shp2, a widely expressed Src homology 2-containing Tyr phosphatase, plays a critical role in the adult brain to control food intake, energy balance, and metabolism. Mice with a neuron-specific, conditional Shp2 deletion were generated by crossing a pan-neuronal Cre-line (CRE3) with Shp2(flox/flox) mice...

Protein tyrosine phosphatase SHP2 plays a crucial role in the development of the central nervous system. To explore the expression and possible role of SHP2 during the course of bacterial meningitis, this article reports a juvenile rat bacterial meningitis model established by direct intracisternal injection of Streptococcus pneumoniae. Expression of SHP2 at both mRNA and protein levels were assessed. White blood cell count and concentration of tumor necrosis factor-alpha (TNF-alpha) in cerebrospinal fluid (CSF) were also measured...

Interleukin (IL)-6 is a pleiotropic cytokine whose production by astrocytes in the CNS of transgenic mice (termed GF-IL6) causes neuroinflammation and neurodegeneration. The binding of IL-6 to its receptor (IL6R) triggers gp130-mediated activation of STAT1 and STAT3 as well as SHP2 phosphatase and ERK1/2. We determined the relative contribution of STAT1 to IL-6 signaling and actions in vivo in the brain of GF-IL6 mice. GF-IL6 mice that were null for STAT1 (termed GF-IL6STAT1 KO) were viable, bred normally and physically indistinguishable from GF-IL6 controls...

Normal development of the nervous system relies on the spatially and temporally well-controlled differentiation of neurons and glia. Here, we discuss the intra- and extracellular molecular mechanisms that underlie the sequential genesis of neurons and glia, emphasizing recent studies describing the role of a signaling molecule, the tyrosine phosphatase SHP2, in normal brain development. Activation of SHP2 simultaneously enhances downstream activation of the MEK-ERK pathway, which subsequently promotes neurogenesis, while inhibiting the JAK-STAT pathway, which is critical for astroglial differentiation...

HiB5 is a multipotent hippocampal stem cell line whose differentiation into cells of a neuronal phenotype is promoted by neurotrophic factors such as PDGF and brain-derived neurotrophic factor (BDNF). We examined the potential role of Src homology 2 (SH2)-containing protein tyrosine phosphatase (Shp2) in this differentiation process. We found that Shp2 became tyrosine phosphorylated following PDGF treatment. Wild-type Shp2 enhanced the expression of neurofilament, synapsin I and PSD95 by PDGF and BDNF, whereas their expression was attenuated by the catalytically inactive mutants Shp2C/S and Shp2DeltaP...

The intracellular signaling controlling neural stem/progenitor cell (NSC) self-renewal and neuronal/glial differentiation is not fully understood. We show here that Shp2, an introcellular tyrosine phosphatase with two SH2 domains, plays a critical role in NSC activities. Conditional deletion of Shp2 in neural progenitor cells mediated by Nestin-Cre resulted in early postnatal lethality, impaired corticogenesis, and reduced proliferation of progenitor cells in the ventricular zone. In vitro analyses suggest that Shp2 mediates basic fibroblast growth factor signals in stimulating self-renewing proliferation of NSCs, partly through control of Bmi-1 expression...

Brain-derived neurotrophic factor (BDNF) and other neurotrophins induce a unique prolonged activation of mitogen-activated protein kinase (MAPK) compared with growth factors. Characterization and kinetic and spatial modeling of the signaling pathways underlying this prolonged MAPK activation by BDNF will be important in understanding the physiological role of BDNF in many complex systems in the nervous system. In addition to Shc, fibroblast growth factor receptor substrate 2 (FRS2) is required for the BDNF-induced activation of MAPK...

Calcium influx can promote neuronal differentiation and survival, at least in part by activating Ras and its downstream targets, including the Erk pathway. However, excessive calcium influx can initiate molecular signals leading to neuronal death during excitotoxicity or in neurodegenerative diseases. Here we describe a new signaling pathway associated with calcium influx that contributes to neuronal cell death in cerebellar neurons. Influx of calcium, mediated either by L-type voltage-sensitive calcium channels or glutamate receptors, is associated with the suppression of brain-derived neurotrophic factor (BDNF) activation of Ras and its effectors Erk and Akt...

Shp2, a Src homology 2-containing tyrosine phosphatase, has been implicated in a variety of growth factor or cytokine signaling pathways. However, it is conceivable that this enzyme acts predominantly in one pathway versus the others in a cell, depending on the cellular context. To determine the putative functions of Shp2 in the adult brain, we selectively deleted Shp2 in postmitotic forebrain neurons by crossing CaMKIIalpha-Cre transgenic mice with a conditional Shp2 mutant (Shp2(flox)) strain. Surprisingly, a prominent phenotype of the mutant (CaMKIIalpha-Cre:Shp2(flox/flox) or CaSKO) mice was the development of early-onset obesity, with increased serum levels of leptin, insulin, glucose, and triglycerides...

Grb2-associated binder-1 (Gab1) is a scaffolding/docking protein and contains a Pleckstrin homology domain and potential binding sites for Src homology (SH) 2 and SH3 domains. Gab1 is tyrosine phosphorylated and associates with protein tyrosine phosphatase SHP2 and p85 phosphatidylinositol 3-kinase on stimulation with various cytokines and growth factors, including interleukin-6. We previously demonstrated that interleukin-6-related cytokine, leukemia inhibitory factor (LIF), induced cardiac hypertrophy through gp130...

Peroxisome proliferator-activated receptor (PPAR)-gamma agonists are now emerging as therapeutic drugs for various inflammatory diseases. However, their molecular mechanism of action remains to be elucidated. Here we report a novel mechanism that underlies the PPAR-gamma agonist-mediated suppression of brain inflammation. We show that 15-deoxy-Delta12,14-prostaglandin J(2) (15d-PGJ(2)) and rosiglitazone reduce the phosphorylation of STAT1 and STAT3 as well as Janus kinase 1 (JAK1) and JAK2 in activated astrocytes and microglia...

Insulin resistance is known to play a pivotal role in type 2 diabetes. Senile individuals, besides being prone to insulin resistance and, consequently, to type 2 diabetes, manifest diseases of the central nervous system (CNS) that may be influenced by disturbances of insulin signaling in the brain, such as memory impairment, Parkinson disease, and Alzheimer disease. We investigated the expression and response to insulin of elements involved in the insulin-signaling pathway in the forebrain cortex and cerebellum of rats ages 1 d to 60 wk...

Using the FDC-P1 cell line expressing the exogenous macrophage colony-stimulating factor (M-CSF) receptor, Fms, we have analyzed the role of a new mammalian DOS/Gab-related signaling protein, called Gab3, in macrophage cell development of the mouse. Gab3 contains an amino-terminal pleckstrin homology domain, multiple potential sites for tyrosine phosphorylation and SH2 domain binding, and two major polyproline motifs potentially interacting with SH3 domains. Among the growing family of Gab proteins, Gab3 exhibits a unique and overlapping pattern of expression in tissues of the mouse compared with Gab1 and Gab2...

Caenorhabditis elegans UNC-5 and its mammalian homologues such as RCM are receptors for the secreted axon guidance cue UNC-6/netrin and are required to mediate the repulsive effects of UNC-6/netrin on growth cones. We find that C. elegans UNC-5 and mouse RCM are phosphorylated on tyrosine in vivo. C. elegans UNC-5 tyrosine phosphorylation is reduced in unc-6 null mutants, and RCM tyrosine phosphorylation is induced by netrin-1 in transfected HEK-293 cells, demonstrating that phosphorylation of UNC-5 proteins is enhanced by UNC-6/netrin stimulation in both worms and mammalian cells...