RESUMEN
We recently showed that perineuronal nets (PNNs) enmesh glucoregulatory neurons in the arcuate nucleus (Arc) of the mediobasal hypothalamus (MBH)1, but whether these PNNs play a role in either the pathogenesis of type 2 diabetes (T2D) or its treatment remains unclear. Here we show that PNN abundance within the Arc is markedly reduced in the Zucker diabetic fatty (ZDF) rat model of T2D, compared with normoglycaemic rats, correlating with altered PNN-associated sulfation patterns of chondroitin sulfate glycosaminoglycans in the MBH. Each of these PNN-associated changes is reversed following a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1) at a dose that induces sustained diabetes remission in male ZDF rats. Combined with previous work localizing this FGF1 effect to the Arc area2-4, our finding that enzymatic digestion of Arc PNNs markedly shortens the duration of diabetes remission following icv FGF1 injection in these animals identifies these extracellular matrix structures as previously unrecognized participants in the mechanism underlying diabetes remission induced by the central action of FGF1.
Asunto(s)
Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/fisiopatología , Matriz Extracelular , Factor 1 de Crecimiento de Fibroblastos/uso terapéutico , Hipotálamo/fisiopatología , Neuronas , Anciano , Animales , Glucemia , Peso Corporal , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Ingestión de Alimentos , Factor 1 de Crecimiento de Fibroblastos/administración & dosificación , Humanos , Inyecciones Intraventriculares , Masculino , Persona de Mediana Edad , Ratas , Ratas Wistar , Ratas Zucker , Adulto JovenRESUMEN
In rodent models of type 2 diabetes (T2D), sustained remission of hyperglycemia can be induced by a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1), and the mediobasal hypothalamus (MBH) was recently implicated as the brain area responsible for this effect. To better understand the cellular response to FGF1 in the MBH, we sequenced >79,000 single-cell transcriptomes from the hypothalamus of diabetic Lepob/ob mice obtained on Days 1 and 5 after icv injection of either FGF1 or vehicle. A wide range of transcriptional responses to FGF1 was observed across diverse hypothalamic cell types, with glial cell types responding much more robustly than neurons at both time points. Tanycytes and ependymal cells were the most FGF1-responsive cell type at Day 1, but astrocytes and oligodendrocyte lineage cells subsequently became more responsive. Based on histochemical and ultrastructural evidence of enhanced cell-cell interactions between astrocytes and Agrp neurons (key components of the melanocortin system), we performed a series of studies showing that intact melanocortin signaling is required for the sustained antidiabetic action of FGF1. These data collectively suggest that hypothalamic glial cells are leading targets for the effects of FGF1 and that sustained diabetes remission is dependent on intact melanocortin signaling.
Asunto(s)
Diabetes Mellitus Experimental/dietoterapia , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Factor 1 de Crecimiento de Fibroblastos/administración & dosificación , Hipoglucemiantes/administración & dosificación , Hipotálamo/efectos de los fármacos , Proteínas Recombinantes/administración & dosificación , Proteína Relacionada con Agouti/metabolismo , Animales , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Glucemia/análisis , Comunicación Celular , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/etiología , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/etiología , Diabetes Mellitus Tipo 2/patología , Dieta Alta en Grasa/efectos adversos , Sacarosa en la Dieta/administración & dosificación , Sacarosa en la Dieta/efectos adversos , Humanos , Hipotálamo/citología , Hipotálamo/patología , Inyecciones Intraventriculares , Leptina/genética , Masculino , Melanocortinas/metabolismo , Hormonas Estimuladoras de los Melanocitos/administración & dosificación , Ratones , Ratones Noqueados , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Oligodendroglía/efectos de los fármacos , Oligodendroglía/metabolismo , RNA-Seq , Receptor de Melanocortina Tipo 4/genética , Receptores de Melanocortina/antagonistas & inhibidores , Receptores de Melanocortina/metabolismo , Inducción de Remisión/métodos , Transducción de Señal/efectos de los fármacos , Análisis de la Célula Individual , Técnicas Estereotáxicas , Transcriptoma/efectos de los fármacosRESUMEN
Type 2 diabetes (T2D) is among the most common and costly disorders worldwide. The goal of current medical management for T2D is to transiently ameliorate hyperglycemia through daily dosing of one or more antidiabetic drugs. Hypoglycemia and weight gain are common side effects of therapy, and sustained disease remission is not obtainable with nonsurgical approaches. On the basis of the potent glucose-lowering response elicited by activation of brain fibroblast growth factor (FGF) receptors, we explored the antidiabetic efficacy of centrally administered FGF1, which, unlike other FGF peptides, activates all FGF receptor subtypes. We report that a single intracerebroventricular injection of FGF1 at a dose one-tenth of that needed for antidiabetic efficacy following peripheral injection induces sustained diabetes remission in both mouse and rat models of T2D. This antidiabetic effect is not secondary to weight loss, does not increase the risk of hypoglycemia, and involves a novel and incompletely understood mechanism for increasing glucose clearance from the bloodstream. We conclude that the brain has an inherent potential to induce diabetes remission and that brain FGF receptors are potential pharmacological targets for achieving this goal.
Asunto(s)
Glucemia/efectos de los fármacos , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Factor 1 de Crecimiento de Fibroblastos/farmacología , Tejido Adiposo/efectos de los fármacos , Tejido Adiposo/metabolismo , Animales , Glucemia/metabolismo , Western Blotting , Composición Corporal , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Radioisótopos de Carbono , Desoxiglucosa , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Células Ependimogliales/efectos de los fármacos , Células Ependimogliales/metabolismo , Proteína Forkhead Box O1/genética , Prueba de Tolerancia a la Glucosa , Corazón/efectos de los fármacos , Proteínas de Choque Térmico/efectos de los fármacos , Proteínas de Choque Térmico/metabolismo , Hiperglucemia/metabolismo , Hipotálamo/citología , Hipotálamo/efectos de los fármacos , Hipotálamo/metabolismo , Inyecciones Intraventriculares , Hígado/metabolismo , Masculino , Ratones , Ratones Noqueados , Ratones Obesos , Chaperonas Moleculares , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismo , Miocardio/metabolismo , Proteínas de Neoplasias/efectos de los fármacos , Proteínas de Neoplasias/metabolismo , Proteínas Proto-Oncogénicas c-fos/efectos de los fármacos , Proteínas Proto-Oncogénicas c-fos/metabolismo , Ratas , Ratas Zucker , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptor de Insulina/antagonistas & inhibidores , Receptor de Insulina/genética , Inducción de RemisiónRESUMEN
OBJECTIVE: Lateral supracerebellar-infratentorial approaches are established for lesions in ambient cistern and posterolateral midbrain, but published surgical experiences do not describe results with this approach in the sitting position. Gravity retraction of the cerebellum opens this surgical corridor and dramatically alters exposure, creating 2 variations of the lateral supracerebellar-infratentorial approach: the supracerebellar-supratrochlear approach and the infratentorial-infratrochlear approach. METHODS: We reviewed our experience treating cavernous malformations and arteriovenous malformations (AVMs) of the posteroinferior thalamus and posterolateral midbrain by use of supracerebellar-supratrochlear and infratentorial-infratrochlear approaches. Microsurgical technique, clinical data, radiographic features, and neurological outcomes were evaluated. RESULTS: During an 11-year surgical experience with 341 cavernous malformation patients and 402 AVM patients, 8 patients were identified, 6 with cavernous malformations and 2 with AVMs. Infratentorial-infratrochlear approaches were used in 4 patients (50%), including 3 with inferolateral midbrain cavernous malformations. Supracerebellar-supratrochlear approaches were used in 4 patients (50%), including 2 with posterior thalamic lesions surfacing on pulvinar. Resections were radiographically complete in all cases. There were no new, permanent neurological deficits, nor were there any medical or surgical complications. There has been no evidence of rebleeding or recurrence. CONCLUSIONS: Gravity retraction of the cerebellum transforms the lateral supracerebellar-infratentorial approach, enhancing exposure and approach trajectories that can be achieved with patients in prone or lateral positions. The increased upward viewing angle of the supracerebellar-supratrochlear approach accesses the posteroinferior thalamus. The increased downward-viewing angle of the infratentorial-infratrochlear approach accesses cerebellomesencephalic fissure and posterolateral midbrain. These approaches open wide corridors for safe surgical resection of symptomatic cavernous malformations and AVMs.