V-raf-leukemia viral oncogene 1(RAF1),a serine/threonine protein kinase,is well established to play a crucial role in tumorigenesis and cell development.However,the specific role of hypothalamic RAF1 in regulating ene...V-raf-leukemia viral oncogene 1(RAF1),a serine/threonine protein kinase,is well established to play a crucial role in tumorigenesis and cell development.However,the specific role of hypothalamic RAF1 in regulating energy metabolism remains unknown.In this study,we found that the expression of RAF1 was significantly increased in hypothalamic AgRP neurons of diet-induced obesity(DIO)mice.Under normal chow diet feeding,overexpression of Raf1 in AgRP neurons led to obesity in mice characterized by increased body weight,fat mass,and impaired glucose tolerance.Conversely,Raf1 knockout in AgRP neurons protected against diet-induced obesity,reducing fat mass and improving glucose tolerance.Mechanistically,Raf1 activated the MAPK signaling pathway,culminating in the phosphorylation of cAMP response element-binding protein(CREB),which enhanced transcription of Agrp and Npy.Insulin stimulation further potentiated the RAF1-MEK1/2-ERK1/2-CREB axis,highlighting RAF1's role in integrating hormonal and nutritional signals to regulate energy balance.Collectively,these findings underscore the important role of RAF1 in AgRP neurons in maintaining energy homeostasis and obesity pathogenesis,positioning it and its downstream pathways as potential therapeutic targets for innovative strategies to combat obesity and related metabolic diseases.展开更多
BACKGROUND Noonan syndrome is a relatively common autosomal dominant genetic disorder characterized by cardiovascular defects owing to functional abnormalities in key genes such as RAF1.Mutations in RAF1 are typically...BACKGROUND Noonan syndrome is a relatively common autosomal dominant genetic disorder characterized by cardiovascular defects owing to functional abnormalities in key genes such as RAF1.Mutations in RAF1 are typically associated with hypertrophic cardiomyopathy(HCM).However,in this case,the patient exhibited atrial and ventricular septal defects(VSDs).CASE SUMMARY This case report describes an 11-year-old boy diagnosed with Noonan syndrome,in whom genetic testing revealed a c.770C>T(p.Ser257 Leu)mutation in RAF1.The patient presented with intermittent chest discomfort and shortness of breath,symptoms that significantly worsened after physical activity.Clinical evaluation revealed marked growth retardation and multiple physical abnormalities.Electrocardiographic and echocardiographic assessments revealed VSDs,atrial septal defects,and left ventricular outflow tract obstruction.Following multidisciplinary consultation,the patient underwent cardiac surgical intervention,which led to clinical improvement;however,they subsequently developed a third-degree atrioventricular block,necessitating the implantation of a permanent pacemaker.During follow-up,echocardiographic findings demonstrated near-complete resolution of the shunt across the atrial and ventricular septa,significant improvement in left ventricular outflow tract obstruction,and notable reduction in ventricular septal thickness.A genetic mutation at the c.770C>T(p.Ser257 Leu)locus of RAF1 is typically associated with HCM and pulmonary hypertension.However,this patient’s clinical phenotype manifested as HCM,atrial septal defect,and VSD,suggesting that this mutation may involve a different pathophysiological mechanism.CONCLUSION This case confirms the genotype-phenotype heterogeneity of Noonan syndrome and highlights the complex management requirements of RAF1 mutation-associated cardiac pathologies.Early surgical intervention can ameliorate structural defects,but it must be integrated with genetic counseling and lifelong monitoring to optimize patient outcomes.展开更多
基金support from various sources,including the National Natural Science Foundation of China(Grant Nos.81570774,82070872,92049118,and 82370854)the Junior Thousand Talents Program of China,and the Nanjing Medical University Startup Fund(All awarded to J.L.)support provided by Jiangsu Province's Innovation Personal as well as Innovative and Entrepreneurial Team of Jiangsu Province(Grant No.JSSCTD2021)(All awarded to J.L.).
文摘V-raf-leukemia viral oncogene 1(RAF1),a serine/threonine protein kinase,is well established to play a crucial role in tumorigenesis and cell development.However,the specific role of hypothalamic RAF1 in regulating energy metabolism remains unknown.In this study,we found that the expression of RAF1 was significantly increased in hypothalamic AgRP neurons of diet-induced obesity(DIO)mice.Under normal chow diet feeding,overexpression of Raf1 in AgRP neurons led to obesity in mice characterized by increased body weight,fat mass,and impaired glucose tolerance.Conversely,Raf1 knockout in AgRP neurons protected against diet-induced obesity,reducing fat mass and improving glucose tolerance.Mechanistically,Raf1 activated the MAPK signaling pathway,culminating in the phosphorylation of cAMP response element-binding protein(CREB),which enhanced transcription of Agrp and Npy.Insulin stimulation further potentiated the RAF1-MEK1/2-ERK1/2-CREB axis,highlighting RAF1's role in integrating hormonal and nutritional signals to regulate energy balance.Collectively,these findings underscore the important role of RAF1 in AgRP neurons in maintaining energy homeostasis and obesity pathogenesis,positioning it and its downstream pathways as potential therapeutic targets for innovative strategies to combat obesity and related metabolic diseases.
基金Supported by the Gansu Provincial Science and Technology Plan Project,No.24JRRA886 and No.23JRRA1287Gansu Provincial People’s Hospital:Excellent Doctoral Student Cultivation Program,No.22GSSYD-14.
文摘BACKGROUND Noonan syndrome is a relatively common autosomal dominant genetic disorder characterized by cardiovascular defects owing to functional abnormalities in key genes such as RAF1.Mutations in RAF1 are typically associated with hypertrophic cardiomyopathy(HCM).However,in this case,the patient exhibited atrial and ventricular septal defects(VSDs).CASE SUMMARY This case report describes an 11-year-old boy diagnosed with Noonan syndrome,in whom genetic testing revealed a c.770C>T(p.Ser257 Leu)mutation in RAF1.The patient presented with intermittent chest discomfort and shortness of breath,symptoms that significantly worsened after physical activity.Clinical evaluation revealed marked growth retardation and multiple physical abnormalities.Electrocardiographic and echocardiographic assessments revealed VSDs,atrial septal defects,and left ventricular outflow tract obstruction.Following multidisciplinary consultation,the patient underwent cardiac surgical intervention,which led to clinical improvement;however,they subsequently developed a third-degree atrioventricular block,necessitating the implantation of a permanent pacemaker.During follow-up,echocardiographic findings demonstrated near-complete resolution of the shunt across the atrial and ventricular septa,significant improvement in left ventricular outflow tract obstruction,and notable reduction in ventricular septal thickness.A genetic mutation at the c.770C>T(p.Ser257 Leu)locus of RAF1 is typically associated with HCM and pulmonary hypertension.However,this patient’s clinical phenotype manifested as HCM,atrial septal defect,and VSD,suggesting that this mutation may involve a different pathophysiological mechanism.CONCLUSION This case confirms the genotype-phenotype heterogeneity of Noonan syndrome and highlights the complex management requirements of RAF1 mutation-associated cardiac pathologies.Early surgical intervention can ameliorate structural defects,but it must be integrated with genetic counseling and lifelong monitoring to optimize patient outcomes.
