Role Of Corticotropin-releasing Factor Receptors Research Articles

Transcriptional Regulation, Signaling Pathways, and Subcellular Localization of Corticotropin-Releasing Factor Receptors in the Central Nervous System.

Corticotropin-releasing factor (CRF) receptors CRF-R1 and CRF-R2 are differentially distributed in body tissues, and although they respond differentially to stimuli due to their association with different signaling pathways, both receptors have a fundamental role in the response and adaptation to stressful stimuli. Here, we summarize the reported data on different forms of CRF-R1 and CRF-R2 regulation as well as on their subcellular localization. Although the presence of R1 has been described at pre- and postsynaptic sites, R2 is mainly associated with postsynaptic densities. Different studies have provided valuable information on how these receptors regulate responses at a central level, elucidating different and sometimes synergistic roles in response to stress, but despite their high sequence identity, both receptors have been described to be differentially regulated both by their ligands and by transcriptional factors. To date, and from the point of view of their promoter sequences, it has not yet been reported how the different consensus sites identified in silico could be modulating the transcriptional regulation and expression of the receptors under different conditions, which strongly limits the full understanding of their differential functions, providing a wide field to increase and expand the study of the regulation and role of CRF receptors in the CRF system. SIGNIFICANCE STATEMENT: A large number of physiological functions related to the organization of the stress response in different body tissues are associated with the corticotropin-releasing factor system. This system also plays a relevant role in depression and anxiety disorders, as well as being a direct connection between stress and addiction. A better understanding of how the receptors of this system are regulated would help to expand the understanding of how these receptors respond differently to both drugs and stressful stimuli.

Type 1 Corticotropin-Releasing Factor Receptor Differentially Modulates Neurotransmitter Levels in the Nucleus Accumbens of Juvenile versus Adult Rats.

Adversity is particularly pernicious in early life, increasing the likelihood of developing psychiatric disorders in adulthood. Juvenile and adult rats exposed to social isolation show differences in anxiety-like behaviors and significant changes in dopamine (DA) neurotransmission in the nucleus accumbens (NAc). Brain response to stress is partly mediated by the corticotropin-releasing factor (CRF) system, composed of CRF and its two main receptors, CRF-R1 and CRF-R2. In the NAc shell of adult rats, CRF induces anxiety-like behavior and changes local DA balance. However, the role of CRF receptors in the control of neurotransmission in the NAc is not fully understood, nor is it known whether there are differences between life stages. Our previous data showed that infusion of a CRF-R1 antagonist into the NAc of juvenile rats increased DA levels in response to a depolarizing stimulus and decreased basal glutamate levels. To extend this analysis, we now evaluated the effect of a CRF-R1 antagonist infusion in the NAc of adult rats. Here, we describe that the opposite occurred in the NAc of adult compared to juvenile rats. Infusion of a CRF-R1 antagonist decreased DA and increased glutamate levels in response to a depolarizing stimulus. Furthermore, basal levels of DA, glutamate, and γ-Aminobutyric acid (GABA) were similar in juvenile animals compared to adults. CRF-R1 protein levels and localization were not different in juvenile compared to adult rats. Interestingly, we observed differences in the signaling pathways of CRF-R1 in the NAc of juveniles compared to adult rats. We propose that the function of CRF-R1 receptors is differentially modulated in the NAc according to life stage.

(108) - The role of corticotropin-releasing factor receptors in mediating stress-induced bladder sensitivity in female mice

Patients with interstitial cystitis/painful bladder syndrome (IC/PBS) often report that their symptoms worsen during periods of heightened stress. Exposure to stress early in life can also increase susceptibility to developing IC/PBS, which has been linked to altered regulation of the hypothalamic-pituitary adrenal (HPA) axis. The HPA axis responds to a stressor by releasing corticotropin-releasing factor (CRF), driving downstream release of glucocorticoids. CRF also has peripheral actions on immune cells, bladder urothelium, and enteric neurons. Two CRF receptors have been described, CRF1 and CRF2, that act in opposition to one other to increase and decrease output from the HPA axis, respectively. Antagonism of either receptor has been shown to stabilize mast cells, thereby preventing stress-induced visceral hypersensitivity. Here, we are investigating the potential role of CRF receptors in preventing stress-induced bladder hypersensitivity in a mouse model of early life stress. Mouse pups underwent neonatal maternal separation (NMS) for 3 hours per day from postnatal day (P) 1 to 21 and were weaned on P22. At 10 weeks of age, the visceromotor response (VMR) to urinary bladder distension (UBD) was performed on female naïve and NMS mice. One week later, mice were treated with saline or a CRF1 antagonist (NBI 35965, 20 mg/kg, intraperitoneal) twenty minutes prior to a one hour exposure to water avoidance stress (WAS). Mice were retested for VMR during UBD at 24 hours and 7 days after WAS exposure. Saline-treated NMS mice had a significant increase in VMR at 1d post-WAS compared to baseline measurements and saline-treated naïve-mice. Treatment with CRF1 antagonist significantly decreased VMR in both naïve and NMS mice, at 1d-, but not 7d-post WAS. Our results suggest that antagonizing CRF1 may prevent stress-induced exacerbation of bladder hypersensitivity. Future studies will include testing with CRF2 antagonist and additional behavioral tests. Supported by NIH grant DK099611.

Sa2050 Corticotropin-Releasing Factor (CRF) Peptides Modulates Rat Colonic Neuronal Tau Phosphorylation: Differential Role of CRF Receptors

BACKGROUND: Corticotropin releasing factor receptor-1 (CRF1)-overexpression enhances experimental stress or CRF-induced tau (TAU) phosphorylation in the mouse brain (PNAS, 2012: 109(16):6277-82). CRF is a key mediator of the gut response to stress. Whether CRF affect enteric TAU and whether enteric neuronal TAU modulation impacts gastrointestinal tract functions are not known. AIM: 1) Determine 1) the effect of selective activation of CRF receptors on rat colon primary myneteric neuron Tau 2) the colonic motor response of Tau transgenic mice to acute stress. METHODS: Rat distal colonic primary myenteric neurons were incubated with non-selective CRF1 and 2 receptor agonists (CRF, urocortin 1 (Ucn1)) and selective CRF2 receptor agonist (Ucn2) for 30 min (10 or 100 nM) and pTAU probed by western blot. Rat colon primary myenteric neurons were processed for immunostaining of Tau. Human TauP301L overexpressing and wild-type (WT) mice were exposed to 1-hour novel environment stress and cumulative Fecal Pellet Output (FPO) at 5, 15, 30, 45 and 60 min was monitored. The overexpression of human Tau in the TauOE mice was confirmed by western blotting. RESULTS: Rat colon primary neurons have constitutively active pTau that is suppressed by selective CRF2 receptor activation but not by the non-selective CRF receptor ligand, CRF. Rat colon primary myenteric neurons have abundant Tau. Compared to WT, Tau overexpressing mice have 2-4X increased total Tau mRNA expression, increased defecation (60.7±6.5% increase in 60 min cumulative FPO) response to mild novel environment stress and display altered ileal and colonic CRF2 receptor expression. CONCLUSION: The differential modulation of colonic primary myenteric TAU phophorylation by CRF peptides and the altered colonic motor response to stress in the mice that express phospho TAU in the intestine and the modulation of colonic CRF2 receptor mRNA profile in these mice, suggest a possible interplay between myenteric TAU and CRFsignaling in the colonic response to stress. Supported by R01DK078676 (MM); Veterans Administration Merit Review (MEH-W)

141 Peripheral Corticotropin-Releasing Factor (CRF) Enhances Colonic Mucin Secretion and Modulates MUC2 and MUC4 Gene Expression in Rats: Differential Role of CRF Receptors

141 Peripheral Corticotropin-Releasing Factor (CRF) Enhances Colonic Mucin Secretion and Modulates MUC2 and MUC4 Gene Expression in Rats: Differential Role of CRF Receptors

Differential activation of CRF receptor subtypes removes stress‐induced memory deficit and anxiety

The objective of this study was to investigate the role of corticotropin-releasing factor receptors 1 (CRF(1)) and 2 (CRF(2)) in anxiety-like behavior and learning of C57BL/6J mice after exposure to a stressful stimulus. When C57BL/6J mice were exposed to immobilization (1 h) serving as stressful stimulus, context- and tone-dependent fear conditioning were impaired if the training followed immediately after immobilization. The stress-induced impairment of context-dependent fear conditioning was prevented by specific blockade of CRF(2) of the lateral septum (LS) with anti-sauvagine-30. Immobilization did not only affect conditioned fear, but also enhanced, through CRF(2) of the LS, anxiety-like behavior determined with the elevated plus maze. Recovery from stress-induced anxiety and impairment of context-dependent fear conditioning was observed after 1 h delay of training and required hippocampal CRF(1), as indicated by the finding that this recovery was prevented by blockade of intrahippocampal CRF(1). It was concluded that exposure to a stressor initially affected both anxiety-like behavior and contextual conditioned fear through septal CRF(2), while the later activation of hippocampal CRF(1) resulted in the return to baseline levels of both processes. Intraventricular injection of mouse urocortin 2, a CRF(2)-selective agonist, removed the stress-induced anxiety and learning impairment, but did not reduce the activation of the hypothalamic pituitary adrenal axis indicative of the hormonal stress response. We propose that the enhanced anxiety is the component of the stress response responsible for the memory deficit.

The CRF 1 receptor antagonist, NBI-35965, abolished the activation of locus coeruleus neurons induced by colorectal distension and intracisternal CRF in rats

Corticotropin-releasing factor (CRF) receptors have been reported to play a role in tonic colorectal distension (CRD)-induced activation of locus coeruleus (LC) neurons. We examined the influence of repeated phasic CRDs and intracisternal (ic) CRF on the spontaneous discharge rate of LC neurons in chloral hydrate-anesthetized rats and the role of CRF receptors using the nonselective CRF 1/CRF 2 antagonist, astressin, and the water-soluble CRF 1 receptor antagonist, NBI-35965. Two consecutive phasic CRDs (43.7 ± 1.1 mm Hg, 30 s each) at a 10-min interval increased LC activity to 184.9 ± 15% and 171.9 ± 12.2%, respectively. There was no difference in magnitude, onset (within 1 s), and duration (5–7 min) of the LC responses between the 1st and 2nd CRDs. CRF (300 ng/rat, ic) injected 10 min after the 2nd CRD increased LC activity to 191.1 ± 11.2%. Astressin (3 μg, ic) completely blocked the 2nd CRD- and ic CRF-induced LC activation. Neither ic vehicle nor astressin influenced basal LC neuronal activity. NBI-35965 (10 mg/kg, iv) prevented the 2nd CRD- and ic CRF-induced LC neuronal activation, while at 5 mg significantly reduced the LC response to the 2nd CRD by 80%, but did not block that of ic CRF injected 30 min later. These findings indicate a primary role of brain CRF interacting with CRF 1 receptors in mediating the activation of LC neurons in response to a phasic CRD within the nociceptive range (>40 mm Hg). This activation may have relevance to irritable bowel syndrome characterized by lower pain threshold to CRD and hypervigilance to colonic input.

Corticotropin-releasing factor receptor 1 mediates acute and delayed stress-induced visceral hyperalgesia in maternally separated Long-Evans rats

In rodents, maternal pup interactions play an important role in programming the stress responsiveness of the adult organism. The aims of this study were 1) to determine the effect of different neonatal rearing conditions on acute and delayed stress-induced visceral sensitivity as well as on other measures of stress sensitivity of the adult animal; and 2) to determine the role of corticotropin-releasing factor receptor (CRF-R) subtype 1 (CRF(1)R) in mediating visceral hypersensitivity. Three groups of male Long-Evans rat pups were used: separation from their dam for 180 min daily from postnatal days 2-14 (MS180), daily separation (handling) for 15 min (H), or no handling. The visceromotor responses (VMR) to colorectal distension, stress-induced colonic motility, and anxiety-like behavior were assessed in the adult rats. The VMR was assessed at baseline, immediately after a 1-h water avoidance (WA) stress, and 24 h poststress. Astressin B, a nonselective CRF-R antagonist, or CP-154,526, a selective CRF(1)R antagonist, was administered before the stressor and/or before the 24-h measurement. MS rats developed acute and delayed stress-induced visceral hyperalgesia. In contrast, H rats showed hypoalgesia immediately after WA and no change in VMR on day 2. MS rats with visceral hyperalgesia also exhibited enhanced stress-induced colonic motility and increased anxiety-like behavior. In MS rats, both CRF-R antagonists abolished acute and delayed increases in VMR. Rearing conditions have a significant effect on adult stress responsiveness including immediate and delayed visceral pain responses to an acute stressor. Both acute and delayed stress-induced visceral hypersensitivity in MS rats are mediated by the CRF/CRF(1)R system.

The Role of Corticotropin-Releasing Factor Receptors in Stress and Anxiety

Corticotropin releasing factor (CRF) is a critical integrator of the hypothalamic-pituitary-adrenal (HPA) axis in response to stress. CRF and its related molecule urocortin (UCN) bind CRF receptor 1 (CRFR1) and CRFR2 with distinct affinities. Mice deficient for CRFR1 or CRFR2 were generated in order to determine the physiological role of these receptors. While CRFR1-mutant mice show a depleted stress response and display anxiolytic-like behavior, CRFR2-mutant mice are hypersensitive to stress and display anxiogenic-like behavior. Both CRFR1- and CRFR2-mutant mice show normal basal feeding and weight gain, but CRFR2-mutant mice exhibit decreased food intake following a stress of food deprivation. While CRFR2-mutant mice display increased levels of CRF mRNA in the central nucleus of the amygdala (cAmyg) but not in the paraventricular nucleus of the hypothalamus (PVN), the CRFR1-mutant mice express high levels of CRF in the PVN but normal levels in the cAmyg. CRFR2-mutant mice also display increased levels of Ucn mRNA and protein in the edinger westphal nucleus (EW) as well as an increased number of cells expressing Ucn. The levels of these CRF-receptor ligands reflect the state of the receptor-deficient mice. These results demonstrate a possible modulatory function of CRFR2 in response to CRFR1 stimulation of the HPA axis or anxiety.