an-orthotopic-mouse-model-of-anaplastic-thyroid-carcinoma

An Orthotopic Mouse Model of Anaplastic Thyroid Carcinoma

Several types of animal models of human thyroid carcinomas have been established, including subcutaneous xenograft and orthotopic implantation of cancer ...

Saint Louis University School of Medicine

The identification of mutations in PTPN11 (encoding the protein tyrosine phosphatase Shp2) in families with congenital heart disease has facilitated mechanistic studies of various cardiovascular defects. However, the roles of normal and mutant Shp2 in the developing heart are still poorly understood. Furthermore, it remains unclear how Shp2 loss-of-function (LOF) mutations cause LEOPARD Syndrome (also termed Noonan Syndrome with multiple lentigines), which is characterized by congenital heart defects such as pulmonary valve stenosis and hypertrophic cardiomyopathy (HCM). In normal hearts, Shp2 controls cardiomyocyte size by regulating signaling through protein kinase B (Akt) and mammalian target of rapamycin (mTOR). We hypothesized that Shp2 LOF mutations dysregulate this pathway, resulting in HCM. For our studies, we chose the Shp2 mutation Q510E, a dominant-negative LOF mutation associated with severe early onset HCM. Newborn mice with cardiomyocyte-specific overexpression of Q510E-Shp2 starting before birth displayed increased cardiomyocyte sizes, heart-to-body weight ratios, interventricular septum thickness, and cardiomyocyte disarray. In 3-mo-old hearts, interstitial fibrosis was detected. Echocardiographically, ventricular walls were thickened and contractile function was depressed. In ventricular tissue samples, signaling through Akt/mTOR was hyperactivated, indicating that the presence of Q510E-Shp2 led to upregulation of this pathway. Importantly, rapamycin treatment started shortly after birth rescued the Q510E-Shp2-induced phenotype in vivo. If rapamycin was started at 6 wk of age, HCM was also ameliorated. We also generated a second mouse model in which cardiomyocyte-specific Q510E-Shp2 overexpression started after birth. In contrast to the first model, these mice did not develop HCM. In summary, our studies establish a role for mTOR signaling in HCM caused by Q510E-Shp2. Q510E-Shp2 overexpression in the cardiomyocyte population alone was sufficient to induce the phenotype. Furthermore, the pathomechanism was triggered pre- but not postnatally. However, postnatal rapamycin treatment could still reverse already established HCM, which may have important therapeutic implications.

The PTPN11 loss-of-function mutation Q510E-Shp2 causes hypertrophic cardiomyopathy by dysregulating mTOR signaling.

L&#39;identification des mutations PTPN11 (codant la prot&eacute;ine tyrosine phosphatase Shp2) dans des familles pr&eacute;sentant une cardiopathie cong&eacute;nitale a facilit&eacute; des &eacute;tudes m&eacute;canistes de diverses anomalies cardiovasculaires. Cependant, les r&ocirc;les de Shp2 normal et mutant en plein d&eacute;veloppement sont encore mal compris. En outre, on ne sait comment Shp2 des mutations perte de fonction (LOF) provoquent le Syndrome de l&eacute;opard (aussi appel&eacute; Syndrome de Noonan avec lentigines multiples), qui se caract&eacute;rise par des anomalies cardiaques cong&eacute;nitales d&eacute;fauts tels que st&eacute;nose valvulaire pulmonaire et une cardiomyopathie hypertrophique (HCM). Dans les coeurs normaux, Shp2 contr&ocirc;le cardiomyocyte taille en r&eacute;gulant la signalisation par la prot&eacute;ine kinase B (Akt) et mammalian target of rapamycin (mTOR). Nous avons suppos&eacute; que CAD de mutations de Shp2 LOF cette voie, ayant pour r&eacute;sultat HCM. Pour nos &eacute;tudes, nous avons choisi la mutation de Shp2 Q510E, une mutation de LOF dominant n&eacute;gatif associ&eacute;e &agrave; apparition pr&eacute;coce s&eacute;v&egrave;re HCM. Des souris nouveau-n&eacute;es avec surexpression du cardiomyocyte sp&eacute;cifiques de Q510E-Shp2 commen&ccedil;ant avant la naissance affichent les tailles de cardiomyocyte accrue, rapports poids du c&oelig;ur-&agrave;-corps, &eacute;paisseur du septum interventriculaire et d&eacute;sarroi cardiomyocyte. Dans les 3 mo-coeurs, fibrose interstitielle a &eacute;t&eacute; d&eacute;tect&eacute;e. H&eacute;modynamiques, parois ventriculaires &eacute;taient &eacute;paissies et la fonction contractile &eacute;tait d&eacute;prim&eacute;e. Dans le tissu ventriculaire, &eacute;chantillons, signalisation par Akt/mTOR sont hyperactiv&eacute;, indiquant que la pr&eacute;sence de Q510E-Shp2 a conduit &agrave; une augmentation de cette voie. Ce qui est important, la rapamycine traitement commenc&eacute; peu de temps apr&egrave;s que la naissance, a sauv&eacute; le ph&eacute;notype induite par le Q510E-Shp2 in vivo. Si la rapamycine a d&eacute;but&eacute; &agrave; 6 sem de l&#39;&acirc;ge, HCM a &eacute;t&eacute; &eacute;galement am&eacute;lior&eacute;. Nous avons produit &eacute;galement un second mod&egrave;le de souris dans lequel surexpression de Q510E-Shp2 cardiomyocyte sp&eacute;cifique a commenc&eacute; apr&egrave;s la naissance. Contrairement au premier mod&egrave;le, ces souris n&#39;ont pas d&eacute;velopp&eacute; de HCM. En r&eacute;sum&eacute;, nos &eacute;tudes ont &eacute;tabli un r&ocirc;le pour mTOR signaling in HCM caus&eacute;e par Q510E-Shp2. Q510E-Shp2 surexpression dans la population de cardiomyocyte seule est suffisante pour induire le ph&eacute;notype. En outre, le globalement a &eacute;t&eacute; d&eacute;clench&eacute;e avant mais pas apr&egrave;s la naissance. Cependant, traitement postnatal rapamycine pourrait inverser toujours HCM d&eacute;j&agrave; &eacute;tabli, ce qui peut avoir des implications th&eacute;rapeutiques importantes.

La mutation de perte de fonction de PTPN11 Q510E-Shp2 entra&icirc;ne une cardiomyopathie hypertrophique de signalisation de mTOR dysregulating.

L&#39;identificazione di mutazioni PTPN11 (codifica la fosfatasi tirosina della proteina Shp2) in famiglie con malattia di cuore congenita ha facilitato Studi meccanicistici di vari difetti cardiovascolari. Tuttavia, i ruoli di Shp2 normali e mutanti nel cuore in via di sviluppo sono ancora poco conosciuti. Inoltre, non &egrave; chiaro come i difetti Shp2 perdita di funzione (LOF) mutazioni causano la sindrome LEOPARD (anche chiamata sindrome di Noonan con lentiggini multiple), che &egrave; caratterizzata da cardiopatie congenite come stenosi della valvola polmonare e la cardiomiopatia ipertrofica (HCM). Nei cuori normali, Shp2 controlla la dimensione del cardiomyocyte regolando la segnalazione attraverso la chinasi di proteina B (Akt) e mammalian target of rapamycin (mTOR). Abbiamo ipotizzato che LOF Shp2 mutazioni dysregulate questo percorso, con conseguente HCM. Per i nostri studi, abbiamo scelto la mutazione Shp2 Q510E, una mutazione di LOF dominante-negativo associata a grave ad esordio precoce HCM. Topi neonati con sovraespressione di cardiomyocyte-specifiche di Q510E-Shp2 a partire prima della nascita visualizzato cardiomyocyte aumentato di dimensioni, peso del cuore-a-corpo, lo spessore del setto interventricolare e rapporti cardiomyocyte sbando. Nei cuori 3-mo-vecchio, &egrave; stata rilevata fibrosi interstiziale. Echocardiographically, pareti ventricolari erano ispessiti e funzione contrattile era depresso. In tessuto ventricolare campioni, segnalazione attraverso Akt/mTOR &egrave; stato iperattivazione, indicando che la presenza di Q510E-Shp2 port&ograve; alla sovraregolazione di questo percorso. Soprattutto, rapamicina trattamento iniziato poco dopo la nascita salvato il fenotipo Q510E-Shp2-indotta in vivo. Se rapamicina fu iniziato alla 6 settimana di et&agrave;, HCM inoltre &egrave; stata migliorata. Abbiamo generato anche un secondo modello di topo in cui sovraespressione Q510E-Shp2 cardiomyocyte-specifico iniziato dopo la nascita. In contrasto con il primo modello, questi topi non ha fatto sviluppare HCM. In sintesi, i nostri studi stabiliscono un ruolo per mTOR segnalazione in HCM causata da Q510E-Shp2. Q510E-Shp2 sovraespressione della popolazione cardiomyocyte da sola era sufficiente per indurre il fenotipo. Inoltre, il Pathomechanismus &egrave; stato attivato pre- ma non dopo la nascita. Tuttavia, trattamento postnatale rapamycin potrebbe invertire ancora HCM gi&agrave; affermati, che potrebbe avere importanti implicazioni terapeutiche.

La mutazione di perdita di funzione di PTPN11 Q510E-Shp2 provoca cardiomiopatia ipertrofica da dysregulating mTOR segnalazione.

La identificaci&oacute;n de mutaciones en PTPN11 (codificaci&oacute;n de la prote&iacute;na tirosina fosfatasa Shp2) en familias con enfermedad card&iacute;aca cong&eacute;nita ha facilitado el estudio de mecanismos de varios defectos cardiovasculares. Sin embargo, los papeles de Shp2 normales y mutantes en pleno desarrollo son a&uacute;n poco conocidos. Adem&aacute;s, no queda claro c&oacute;mo Shp2 mutaciones de p&eacute;rdida de funci&oacute;n (LOF) causan s&iacute;ndrome del leopardo (tambi&eacute;n llamado s&iacute;ndrome de Noonan con lentigines m&uacute;ltiples), que se caracteriza por card&iacute;acos cong&eacute;nitos defectos tales como estenosis de la v&aacute;lvula pulmonar y cardiomiopat&iacute;a hipertr&oacute;fica (HCM). En corazones normales, Shp2 controla el tama&ntilde;o del cardiomiocito regulando la se&ntilde;alizaci&oacute;n a trav&eacute;s de la prote&iacute;na quinasa B (Akt) y blanco mam&iacute;fero de rapamicina (mTOR). Presumimos desregulen de mutaciones de Shp2 LOF esta v&iacute;a, dando por resultado HCM. Para nuestros estudios, elegimos la mutaci&oacute;n Shp2 Q510E, una mutaci&oacute;n de LOF dominante negativo asociada con aparici&oacute;n temprana severa HCM. Ratones reci&eacute;n nacidos con sobreexpresi&oacute;n de cardiomiocitos espec&iacute;ficos de Q510E-Shp2 a partir antes del nacimiento muestran mayor cardiomiocitos tama&ntilde;os, ratios de coraz&oacute;n-peso, espesor del tabique interventricular y cardiomiocitos desorden. Mes-viejo 3 corazones, detectaron fibrosis intersticial. Ecocardiogr&aacute;ficamente, paredes ventriculares fueron espesadas y funci&oacute;n contr&aacute;ctil fue presionada. En el tejido ventricular muestras, se&ntilde;alizaci&oacute;n a trav&eacute;s de Akt/mTOR fue ligerament, indicando que la presencia de Q510E-Shp2 condujo a la regulaci&oacute;n al alza de esta v&iacute;a. Lo importante, tratamiento de rapamicina comenzado poco despu&eacute;s de nacer rescat&oacute; el fenotipo Q510E-Shp2-inducido in vivo. Si la rapamicina se inici&oacute; a las 6 semanas de edad, tambi&eacute;n se mejor&oacute; la HCM. Tambi&eacute;n generamos un segundo modelo de rat&oacute;n en el que Q510E Shp2 sobreexpresi&oacute;n de cardiomiocitos espec&iacute;ficos comenz&oacute; despu&eacute;s del nacimiento. En contraste con el primer modelo, estos ratones no desarrollaron HCM. En Resumen, nuestros estudios establecen un papel de mTOR en HCM causada por Q510E-Shp2. Q510E-Shp2 sobreexpresi&oacute;n en la poblaci&oacute;n de cardiomiocitos sola fue suficiente para inducir el fenotipo. Adem&aacute;s, el pathomechanism despert&oacute; pre- pero no postnatal. Sin embargo, tratamiento postnatal rapamicina todav&iacute;a podr&iacute;a invertir HCM ya establecida, que puede tener importantes implicaciones terap&eacute;uticas.

La mutaci&oacute;n de la p&eacute;rdida de funci&oacute;n de PTPN11 Shp2 Q510E causa miocardiopat&iacute;a hipertr&oacute;fica mediante se&ntilde;alizaci&oacute;n mTOR en dysregulating.

Ashley Reeb

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