RESUMO
Understanding the neural basis of infant social behaviors is crucial for elucidating the mechanisms of early social and emotional development. In this work, we report a specific population of somatostatin-expressing neurons in the zona incerta (ZISST) of preweaning mice that responds dynamically to social interactions, particularly those with their mother. Bidirectional neural activity manipulations in pups revealed that widespread connectivity of preweaning ZISST neurons to sensory, emotional, and cognitive brain centers mediates two key adaptive functions associated with maternal presence: the reduction of behavior distress and the facilitation of learning. These findings reveal a population of neurons in the infant mouse brain that coordinate the positive effects of the relationship with the mother on an infant's behavior and physiology.
Assuntos
Neurônios , Comportamento Social , Interação Social , Somatostatina , Zona Incerta , Animais , Feminino , Masculino , Camundongos , Emoções , Aprendizagem , Comportamento Materno , Neurônios/metabolismo , Neurônios/fisiologia , Somatostatina/metabolismo , Zona Incerta/metabolismo , Zona Incerta/fisiologiaRESUMO
Anorexia nervosa (AN) is a psychiatric illness with the highest mortality. Current treatment options have been limited to psychotherapy and nutritional support, with low efficacy and high relapse rates. Hypothalamic AgRP (agouti-related peptide) neurons that coexpress AGRP and neuropeptide Y (NPY) play a critical role in driving feeding while also modulating other complex behaviors. We have previously reported that genetic ablation of Tet3, which encodes a member of the TET family dioxygenases, specifically in AgRP neurons in mice, activates these neurons and increases the expression of AGRP, NPY, and the vesicular GABA transporter (VGAT), leading to hyperphagia and anxiolytic effects. Bobcat339 is a synthetic small molecule predicted to bind to the catalytic pockets of TET proteins. Here, we report that Bobcat339 is effective in mitigating AN and anxiety/depressive-like behaviors using a well-established mouse model of activity-based anorexia (ABA). We show that treating mice with Bobcat339 decreases TET3 expression in AgRP neurons and activates these neurons leading to increased feeding, decreased compulsive running, and diminished lethality in the ABA model. Mechanistically, Bobcat339 induces TET3 protein degradation while simultaneously stimulating the expression of AGRP, NPY, and VGAT in a TET3-dependent manner both in mouse and human neuronal cells, demonstrating a conserved, previously unsuspected mode of action of Bobcat339. Our findings suggest that Bobcat339 may potentially be a therapeutic for anorexia nervosa and stress-related disorders.
Assuntos
Anorexia Nervosa , Dioxigenases , Camundongos , Humanos , Animais , Proteína Relacionada com Agouti/genética , Proteína Relacionada com Agouti/metabolismo , Anorexia Nervosa/tratamento farmacológico , Anorexia Nervosa/metabolismo , Neurônios/metabolismo , Hipotálamo/metabolismo , Modelos Animais , Dioxigenases/metabolismoRESUMO
The TET family of dioxygenases promote DNA demethylation by oxidizing 5-methylcytosine to 5-hydroxymethylcytosine (5hmC). Hypothalamic agouti-related peptide-expressing (AGRP-expressing) neurons play an essential role in driving feeding, while also modulating nonfeeding behaviors. Besides AGRP, these neurons produce neuropeptide Y (NPY) and the neurotransmitter GABA, which act in concert to stimulate food intake and decrease energy expenditure. Notably, AGRP, NPY, and GABA can also elicit anxiolytic effects. Here, we report that in adult mouse AGRP neurons, CRISPR-mediated genetic ablation of Tet3, not previously known to be involved in central control of appetite and metabolism, induced hyperphagia, obesity, and diabetes, in addition to a reduction of stress-like behaviors. TET3 deficiency activated AGRP neurons, simultaneously upregulated the expression of Agrp, Npy, and the vesicular GABA transporter Slc32a1, and impeded leptin signaling. In particular, we uncovered a dynamic association of TET3 with the Agrp promoter in response to leptin signaling, which induced 5hmC modification that was associated with a chromatin-modifying complex leading to transcription inhibition, and this regulation occurred in both the mouse models and human cells. Our results unmasked TET3 as a critical central regulator of appetite and energy metabolism and revealed its unexpected dual role in the control of feeding and other complex behaviors through AGRP neurons.
Assuntos
Ansiolíticos , Dioxigenases , 5-Metilcitosina/metabolismo , Proteína Relacionada com Agouti/genética , Proteína Relacionada com Agouti/metabolismo , Animais , Ansiolíticos/farmacologia , Cromatina/metabolismo , Dioxigenases/genética , Dioxigenases/metabolismo , Humanos , Hipotálamo/metabolismo , Leptina/metabolismo , Camundongos , Neurônios/metabolismo , Neuropeptídeo Y/metabolismo , Ácido gama-Aminobutírico/genética , Ácido gama-Aminobutírico/metabolismo , Ácido gama-Aminobutírico/farmacologiaRESUMO
Dysregulation of long interspersed nuclear element 1 (LINE-1, L1), a dominant class of transposable elements in the human genome, has been linked to neurodegenerative diseases, but whether elevated L1 expression is sufficient to cause neurodegeneration has not been directly tested. Here, we show that the cerebellar expression of L1 is significantly elevated in ataxia telangiectasia patients and strongly anti-correlated with the expression of epigenetic silencers. To examine the role of L1 in the disease etiology, we developed an approach for direct targeting of the L1 promoter for overexpression in mice. We demonstrated that L1 activation in the cerebellum led to Purkinje cell dysfunctions and degeneration and was sufficient to cause ataxia. Treatment with a nucleoside reverse transcriptase inhibitor blunted ataxia progression by reducing DNA damage, attenuating gliosis, and reversing deficits of molecular regulators for calcium homeostasis in Purkinje cells. Our study provides the first direct evidence that L1 activation can drive neurodegeneration.
Assuntos
Elementos de DNA Transponíveis , Inibidores da Transcriptase Reversa , Animais , Humanos , Camundongos , Ataxia/metabolismo , Cálcio/metabolismo , Cerebelo/metabolismo , Nucleosídeos/metabolismo , Células de Purkinje/fisiologia , Inibidores da Transcriptase Reversa/metabolismo , Elementos Nucleotídeos Longos e DispersosRESUMO
Hypothalamic agouti-related peptide and neuropeptide Y-expressing (AgRP) neurons have a critical role in both feeding and non-feeding behaviors of newborn, adolescent, and adult mice, suggesting their broad modulatory impact on brain functions. Here we show that constitutive impairment of AgRP neurons or their peripubertal chemogenetic inhibition resulted in both a numerical and functional reduction of neurons in the medial prefrontal cortex (mPFC) of mice. These changes were accompanied by alteration of oscillatory network activity in mPFC, impaired sensorimotor gating, and altered ambulatory behavior that could be reversed by the administration of clozapine, a non-selective dopamine receptor antagonist. The observed AgRP effects are transduced to mPFC in part via dopaminergic neurons in the ventral tegmental area and may also be conveyed by medial thalamic neurons. Our results unmasked a previously unsuspected role for hypothalamic AgRP neurons in control of neuronal pathways that regulate higher-order brain functions during development and in adulthood.
Assuntos
Hipotálamo , Neuropeptídeo Y , Animais , Camundongos , Proteína Relacionada com Agouti/metabolismo , Neurônios Dopaminérgicos/metabolismo , Hipotálamo/metabolismo , Neuropeptídeo Y/metabolismo , Córtex Pré-Frontal/metabolismoRESUMO
BACKGROUND: Estriol (E3) is a steroid hormone formed only during pregnancy in primates including humans. Although E3 is synthesized at large amounts through a complex pathway involving the fetus and placenta, it is not required for the maintenance of pregnancy and has classically been considered virtually inactive due to associated very weak canonical estrogen signaling. However, estrogen exposure during pregnancy may have an effect on organs both within and outside the reproductive system, and compounds with binding affinity for estrogen receptors weaker than E3 have been found to impact reproductive organs and the brain. Here, we explore potential effects of E3 on fetal development using mouse as a model system. RESULTS: We administered E3 to pregnant mice, exposing the fetus to E3. Adult females exposed to E3 in utero (E3-mice) had increased fertility and superior pregnancy outcomes. Female and male E3-mice showed decreased anxiety and increased exploratory behavior. The expression levels and DNA methylation patterns of multiple genes in the uteri and brains of E3-mice were distinct from controls. E3 promoted complexing of estrogen receptors with several DNA/histone modifiers and their binding to target genes. E3 functions by driving epigenetic change, mediated through epigenetic modifier interactions with estrogen receptors rather than through canonical nuclear transcriptional activation. CONCLUSIONS: We identify an unexpected functional role for E3 in fetal reproductive system and brain. We further identify a novel mechanism of estrogen action, through recruitment of epigenetic modifiers to estrogen receptors and their target genes, which is not correlated with the traditional view of estrogen potency.
Assuntos
Estrogênios , Receptores de Estrogênio , Animais , Encéfalo/metabolismo , Epigênese Genética , Estriol , Estrogênios/genética , Estrogênios/metabolismo , Feminino , Feto/metabolismo , Masculino , Camundongos , Gravidez , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , EsteroidesRESUMO
Endometriosis is a gynecological disease affecting 6-10% of women of reproductive age. In addition to gynecologic symptoms, endometriosis is associated with various systemic effects, including inflammation, altered body weight, and behavioral changes. Previous murine studies demonstrate that endometriosis is causally inked to increased pain sensitization, behavioral changes, and low body mass index (BMI). One possible cellular target that may mediate some of these findings is the hypocretin/orexin neurons. This neuronal system plays a role in regulating wakefulness/sleep cycles, pain perception, and appetite. We hypothesize that endometriosis alters activity level of the hypocretin/orexin (Hcrt) neuronal system. Mice underwent endometriosis induction surgeries (endo) or sham surgeries (sham) for the development of the experimental model. Immunocytochemistry was performed on harvested samples from the lateral hypothalamus, and activation levels of Hcrt cells were examined by quantifying the expression of phosphorylation of cAMP-responsive element binding protein (CREB) in these cells after an acute stress in sham and endo mice. Mice with endometriosis had greater Hcrt neurons activation than sham mice. Mice with endometriosis fed with high fat diet showed a lower fat/body weight and fat/lean tissue ratio compared to mice without endometriosis. There was no significant difference in food intake between sham and endometriosis mice. These results demonstrate that endometriosis is associated with low body mass and increased hypocretin/orexin activity, which could be implicated in the behavioral changes and to differences in body composition.
Assuntos
Endometriose/metabolismo , Região Hipotalâmica Lateral/metabolismo , Neurônios/metabolismo , Orexinas/metabolismo , Animais , Peso Corporal/fisiologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Dieta Hiperlipídica , Modelos Animais de Doenças , Feminino , CamundongosRESUMO
The hypocretin/orexin (Hcrt/Orx) system in the perifornical lateral hypothalamus has been recognized as a critical node in a complex network of neuronal systems controlling both physiology and behavior in vertebrates. Our understanding of the Hcrt/Orx system and its array of functions and actions has grown exponentially in merely 2 decades. This review will examine the latest progress in discerning the roles played by the Hcrt/Orx system in regulating homeostatic functions and in executing instinctive and learned behaviors. Furthermore, the gaps that currently exist in our knowledge of sex-related differences in this field of study are discussed.
Assuntos
Neuropeptídeos , Animais , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Neurônios/fisiologia , Neuropeptídeos/fisiologia , OrexinasRESUMO
Microglia have been implicated in synapse remodeling by phagocytosis of synaptic elements in the adult brain, but the mechanisms involved in the regulation of this process are ill-defined. By examining microglia-neuronal interaction in the ventral hippocampus, we found a significant reduction in spine synapse number during the light phase of the light/dark cycle accompanied by increased microglia-synapse contacts and an elevated amount of microglial phagocytic inclusions. This was followed by a transient rise in microglial production of reactive oxygen species (ROS) and a concurrent increase in expression of uncoupling protein 2 (Ucp2), a regulator of mitochondrial ROS generation. Conditional ablation of Ucp2 from microglia hindered phasic elimination of spine synapses with consequent accumulations of ROS and lysosome-lipid droplet complexes, which resulted in hippocampal neuronal circuit dysfunctions assessed by electrophysiology, and altered anxiety-like behavior. These observations unmasked a novel and chronotypical interaction between microglia and neurons involved in the control of brain functions.
Assuntos
Ansiedade , Hipocampo , Microglia , Neurônios , Proteína Desacopladora 2/genética , Animais , Feminino , Masculino , Camundongos , Camundongos Knockout , Vias Neurais , SinapsesRESUMO
Hypothalamic feeding circuits have been identified as having innate synaptic plasticity, mediating adaption to the changing metabolic milieu by controlling responses to feeding and obesity. However, less is known about the regulatory principles underlying the dynamic changes in agouti-related protein (AgRP) perikarya, a region crucial for gating of neural excitation and, hence, feeding. Here we show that AgRP neurons activated by food deprivation, ghrelin administration, or chemogenetics decreased their own inhibitory tone while triggering mitochondrial adaptations in neighboring astrocytes. We found that it was the inhibitory neurotransmitter GABA released by AgRP neurons that evoked this astrocytic response; this in turn resulted in increased glial ensheetment of AgRP perikarya by glial processes and increased excitability of AgRP neurons. We also identified astrocyte-derived prostaglandin E2, which directly activated - via EP2 receptors - AgRP neurons. Taken together, these observations unmasked a feed-forward, self-exciting loop in AgRP neuronal control mediated by astrocytes, a mechanism directly relevant for hunger, feeding, and overfeeding.
Assuntos
Proteína Relacionada com Agouti , Astrócitos/metabolismo , Fome , Hipotálamo/metabolismo , Plasticidade Neuronal , Neurônios/metabolismo , Proteína Relacionada com Agouti/genética , Proteína Relacionada com Agouti/metabolismo , Animais , Masculino , Camundongos , Camundongos Transgênicos , Receptores de Prostaglandina E Subtipo EP2/metabolismoRESUMO
The basolateral amygdala (BLA) is critical for associating initially neutral cues with appetitive and aversive stimuli and receives dense neuromodulatory acetylcholine (ACh) projections. We measured BLA ACh signaling and activity of neurons expressing CaMKIIα (a marker for glutamatergic principal cells) in mice during cue-reward learning using a fluorescent ACh sensor and calcium indicators. We found that ACh levels and nucleus basalis of Meynert (NBM) cholinergic terminal activity in the BLA (NBM-BLA) increased sharply in response to reward-related events and shifted as mice learned the cue-reward contingency. BLA CaMKIIα neuron activity followed reward retrieval and moved to the reward-predictive cue after task acquisition. Optical stimulation of cholinergic NBM-BLA terminal fibers led to a quicker acquisition of the cue-reward contingency. These results indicate BLA ACh signaling carries important information about salient events in cue-reward learning and provides a framework for understanding how ACh signaling contributes to shaping BLA responses to emotional stimuli.
Assuntos
Acetilcolina/metabolismo , Complexo Nuclear Basolateral da Amígdala/metabolismo , Aprendizagem/fisiologia , Recompensa , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Sinais (Psicologia) , Feminino , Masculino , Camundongos , Neurônios/metabolismo , OptogenéticaRESUMO
The brain has evolved in an environment where food sources are scarce, and foraging for food is one of the major challenges for survival of the individual and species. Basic and clinical studies show that obesity or overnutrition leads to overwhelming changes in the brain in animals and humans. However, the exact mechanisms underlying the consequences of excessive energy intake are not well understood. Neurons expressing the neuropeptide hypocretin/orexin (Hcrt) in the lateral/perifonical hypothalamus (LH) are critical for homeostatic regulation, reward seeking, stress response, and cognitive functions. In this study, we examined adaptations in Hcrt cells regulating behavioral responses to salient stimuli in diet-induced obese mice. Our results demonstrated changes in primary cilia, synaptic transmission and plasticity, cellular responses to neurotransmitters necessary for reward seeking, and stress responses in Hcrt neurons from obese mice. Activities of neuronal networks in the LH and hippocampus were impaired as a result of decreased hypocretinergic function. The weakened Hcrt system decreased reward seeking while altering responses to acute stress (stress-coping strategy), which were reversed by selectively activating Hcrt cells with chemogenetics. Taken together, our data suggest that a deficiency in Hcrt signaling may be a common cause of behavioral changes (such as lowered arousal, weakened reward seeking, and altered stress response) in obese animals.
Assuntos
Comportamento Alimentar , Hipotálamo , Rede Nervosa , Neurônios , Obesidade , Orexinas , Animais , Hipotálamo/metabolismo , Hipotálamo/patologia , Hipotálamo/fisiopatologia , Masculino , Camundongos , Camundongos Transgênicos , Rede Nervosa/metabolismo , Rede Nervosa/patologia , Rede Nervosa/fisiopatologia , Neurônios/metabolismo , Neurônios/patologia , Obesidade/genética , Obesidade/metabolismo , Obesidade/patologia , Obesidade/fisiopatologia , Orexinas/genética , Orexinas/metabolismo , Estresse Psicológico/genética , Estresse Psicológico/metabolismo , Estresse Psicológico/patologia , Estresse Psicológico/fisiopatologiaRESUMO
OBJECTIVE: To evaluate if oocyte penetration and viability can be confirmed by an electrical resistance increase. Automated (robotic) intracytoplasmic sperm injection (ICSI) requires confirmation of oolemma penetration before sperm injection. Visual assessment using image processing algorithms have been developed but remain unreliable. We hypothesized that an increase in electrical resistance upon oolemma piercing during ICSI can serve as an objective tool to confirm oocyte penetration and viability. DESIGN: Experimental study. SETTING: Research laboratory in an academic center. PATIENTS/ANIMALS: Oocytes from female mice and women undergoing oocyte retrieval procedure. INTERVENTION: Oolemma piercing attempts with the ICSI pipette were performed by advancing the pipette towards mature (metaphase II) oocytes collected from 6 to 12-week-old mice and immature (germinal vesicle stage and metaphase I) oocytes donated by women who underwent oocyte retrieval. Electrical resistance was measured using a conventional electrophysiological setup that includes an electrical resistance meter and two electrical wires located in the lumina of the holding and ICSI pipettes. MAIN OUTCOME MEASURE(S): The measure of interest was the change in electrical resistance (ΔR) before and after advancing the ICSI pipette in an attempt to penetrate an oocyte. The experiments of resistance measurements were done in 3 steps: Step 1 (proof of concept), penetrated vs. non-penetrated mouse oocytes. Step 2, mouse oocytes with visually intact oolemma vs. fragmented mouse oocytes. Step 3, human oocytes with visually intact oolemma vs. fragmented human oocytes. For each group, median and range (in parenthesis) of ΔR were determined in MΩ. Mann-Whitney test was performed to compare the two groups in each step. RESULTS: In Step 1, the penetrated mouse oocytes showed a statistically significant resistance increase compared to the non-penetrated ones (n = 20, median ΔR = 7.79 [2.57 - 106.00] vs. n = 15, median ΔR = 0.10 [-0.06 - 0.69], respectively. In Step 2, the mouse oocytes with visually intact oolemma showed a statistically significant resistance increase compared to the fragmented ones (n = 45, median ΔR = 6.5 [0.1 - 191.7] vs. n = 13, median ΔR = 0.1 [-0.3 - 2.2], respectively. In Step 3, the human oocytes with visually intact oolemma showed a statistically significant resistance increase compared to the fragmented ones (n = 96, median ΔR = 1.92 [-0.05 - 6.70] vs. n = 17, median ΔR = 0.11 [0.00 - 0.30], respectively. CONCLUSIONS: An electrical resistance increase can serve as a reliable tool to confirm oocyte penetration and viability, independent of optical visualization. Following further validation and safety assessment, this technology can potentially be integrated into manual and robotic ICSI systems.
Assuntos
Automação/métodos , Impedância Elétrica , Oócitos/fisiologia , Injeções de Esperma Intracitoplásmicas/métodos , Interações Espermatozoide-Óvulo/fisiologia , Animais , Automação/instrumentação , Sobrevivência Celular/fisiologia , Sistemas Computacionais , Feminino , Humanos , Masculino , Camundongos , Injeções de Esperma Intracitoplásmicas/instrumentação , Espermatozoides/fisiologiaRESUMO
We hypothesized that bone evolved, in part, to enhance the ability of bony vertebrates to escape danger in the wild. In support of this notion, we show here that a bone-derived signal is necessary to develop an acute stress response (ASR). Indeed, exposure to various types of stressors in mice, rats (rodents), and humans leads to a rapid and selective surge of circulating bioactive osteocalcin because stressors favor the uptake by osteoblasts of glutamate, which prevents inactivation of osteocalcin prior to its secretion. Osteocalcin permits manifestations of the ASR to unfold by signaling in post-synaptic parasympathetic neurons to inhibit their activity, thereby leaving the sympathetic tone unopposed. Like wild-type animals, adrenalectomized rodents and adrenal-insufficient patients can develop an ASR, and genetic studies suggest that this is due to their high circulating osteocalcin levels. We propose that osteocalcin defines a bony-vertebrate-specific endocrine mediation of the ASR.
Assuntos
Osso e Ossos/metabolismo , Osteoblastos/metabolismo , Osteocalcina/sangue , Estresse Fisiológico/genética , Insuficiência Adrenal/metabolismo , Adrenalectomia , Adulto , Animais , Células Cultivadas , Feminino , Ácido Glutâmico/metabolismo , Voluntários Saudáveis , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pessoa de Meia-Idade , Neurônios/metabolismo , Osteocalcina/genética , Sistema Nervoso Parassimpático/citologia , Ratos , Ratos Sprague-DawleyRESUMO
OBJECTIVE: Dopamine neurons in the Substantia nigra (SN) play crucial roles in control of voluntary movement. Extensive degeneration of this neuronal population is the cause of Parkinson's disease (PD). Many factors have been linked to SN DA neuronal survival, including neuronal pacemaker activity (responsible for maintaining basal firing and DA tone) and mitochondrial function. Dln-101, a naturally occurring splice variant of the human ghrelin gene, targets the ghrelin receptor (GHSR) present in the SN DA cells. Ghrelin activation of GHSR has been shown to protect SN DA neurons against 1-methyl-4-phenyl-1,2,5,6 tetrahydropyridine (MPTP) treatment. We decided to compare the actions of Dln-101 with ghrelin and identify the mechanisms associated with neuronal survival. METHODS: Histologial, biochemical, and behavioral parameters were used to evaluate neuroprotection. Inflammation and redox balance of SN DA cells were evaluated using histologial and real-time PCR analysis. Designer Receptors Exclusively Activated by Designer Drugs (DREADD) technology was used to modulate SN DA neuron electrical activity and associated survival. Mitochondrial dynamics in SN DA cells was evaluated using electron microscopy data. RESULTS: Here, we report that the human isoform displays an equivalent neuroprotective factor. However, while exogenous administration of mouse ghrelin electrically activates SN DA neurons increasing dopamine output, as well as locomotion, the human isoform significantly suppressed dopamine output, with an associated decrease in animal motor behavior. Investigating the mechanisms by which GHSR mediates neuroprotection, we found that dopamine cell-selective control of electrical activity is neither sufficient nor necessary to promote SN DA neuron survival, including that associated with GHSR activation. We found that Dln101 pre-treatment diminished MPTP-induced mitochondrial aberrations in SN DA neurons and that the effect of Dln101 to protect dopamine cells was dependent on mitofusin 2, a protein involved in the process of mitochondrial fusion and tethering of the mitochondria to the endoplasmic reticulum. CONCLUSIONS: Taken together, these observations unmasked a complex role of GHSR in dopamine neuronal protection independent on electric activity of these cells and revealed a crucial role for mitochondrial dynamics in some aspects of this process.
Assuntos
Neurônios Dopaminérgicos/efeitos dos fármacos , Grelina/química , Intoxicação por MPTP/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Fragmentos de Peptídeos/farmacologia , Substância Negra/efeitos dos fármacos , Potenciais de Ação , Animais , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/fisiologia , Camundongos , Fármacos Neuroprotetores/uso terapêutico , Fragmentos de Peptídeos/uso terapêutico , Receptores de Grelina/metabolismo , Substância Negra/citologiaRESUMO
Tumour necrotic factor receptor-2 (TNFR2) has been to be cardiac-protective and is expressed in cardiac progenitor cells. Our goal is to define the mechanism for TNFR2-mediated cardiac stem cell activation and differentiation. By employing a protocol of in vitro cardiac stem cell (CSC) differentiation from human inducible pluripotent stem cell (hiPSC), we show that expression of TNFR2 precedes expression of CSC markers followed by expression of mature cardiomyocyte proteins. Activation of TNFR2 by a specific agonist promotes whereas inhibition of TNFR2 by neutralizing antibody diminishes hiPSC-based CSC differentiation. Interestingly, pluripotent cell factor RNA-binding protein Lin28 enhances TNFR2 protein expression in early CSC activation by directly binding to a conserved Lin28-motif within the 3'UTR of Tnfr2 mRNA. Furthermore, inhibition of Lin28 blunts TNFR2 expression and TNFR2-dependent CSC activation and differentiation. Our study demonstrates a critical role of Lin28-TNFR2 axis in CSC activation and survival, providing a novel strategy to enhance stem cell-based therapy for the ischaemic heart diseases.
Assuntos
Diferenciação Celular , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Miócitos Cardíacos/citologia , Proteínas de Ligação a RNA/metabolismo , Receptores Tipo II do Fator de Necrose Tumoral/metabolismo , Células Cultivadas , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Miócitos Cardíacos/metabolismo , Transdução de SinaisRESUMO
The gut is now recognized as a major regulator of motivational and emotional states. However, the relevant gut-brain neuronal circuitry remains unknown. We show that optical activation of gut-innervating vagal sensory neurons recapitulates the hallmark effects of stimulating brain reward neurons. Specifically, right, but not left, vagal sensory ganglion activation sustained self-stimulation behavior, conditioned both flavor and place preferences, and induced dopamine release from Substantia nigra. Cell-specific transneuronal tracing revealed asymmetric ascending pathways of vagal origin throughout the CNS. In particular, transneuronal labeling identified the glutamatergic neurons of the dorsolateral parabrachial region as the obligatory relay linking the right vagal sensory ganglion to dopamine cells in Substantia nigra. Consistently, optical activation of parabrachio-nigral projections replicated the rewarding effects of right vagus excitation. Our findings establish the vagal gut-to-brain axis as an integral component of the neuronal reward pathway. They also suggest novel vagal stimulation approaches to affective disorders.
Assuntos
Intestinos/fisiologia , Recompensa , Substância Negra/fisiologia , Nervo Vago/fisiologia , Vias Aferentes/metabolismo , Vias Aferentes/fisiologia , Animais , Dopamina/metabolismo , Neurônios Dopaminérgicos/fisiologia , Ácido Glutâmico/metabolismo , Intestinos/inervação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , OptogenéticaRESUMO
Endometriosis is an estrogen-dependent inflammatory disorder among reproductive-aged women associated with pelvic pain, anxiety, and depression. Pain is characterized by central sensitization; however, it is not clear if endometriosis leads to increased pain perception or if women with the disease are more sensitive to pain, increasing the detection of endometriosis. Endometriosis was induced in mice and changes in behavior including pain perception, brain electrophysiology, and gene expression were characterized. Behavioral tests revealed that mice with endometriosis were more depressed, anxious and sensitive to pain compared to sham controls. Microarray analyses confirmed by qPCR identified differential gene expression in several regions of brain in mice with endometriosis. In these mice, genes such as Gpr88, Glra3 in insula, Chrnb4, Npas4 in the hippocampus, and Lcn2 in the amygdala were upregulated while Lct, Serpina3n (insula), and Nptx2 (amygdala) were downregulated. These genes are involved in anxiety, locomotion, and pain. Patch clamp recordings in the amygdala were altered in endometriosis mice demonstrating an effect of endometriosis on brain electrophysiology. Endometriosis induced pain sensitization, anxiety, and depression by modulating brain gene expression and electrophysiology; the effect of endometriosis on the brain may underlie pain sensitization and mood disorders reported in women with the disease.