Effects Of Neuropeptide Y Research Articles

Neuropeptide Y Induces Cardiomyocyte Hypertrophy via Attenuating miR-29a-3p in Neonatal Rat Cardiomyocytes.

Neuropeptide Y (NPY) has been well known to induce Cardiomyocyte Hypertrophy (CH), which is possibly caused by disruption of cardiac cell energy balance. As mitochondria is losely related to energy metabolism, in this study, we investigated the changes in mitochondrial Dynamics-related protein (Drp1) expression under the action of NPY. miRNA-29a, a endogenous noncoding small molecule RNA which is involved in many cardiac diseases, by using a bioinformatics tool, we found a potential binding site of miRNA-29a on the Drp1 mRNA, and suggesting that miRNA-29a might play a regulatory role. To investigate the role of miR-29a-3p in the process of NPY-induced CH, and further explore it's predicted relationship with Drp1. The expression levels of miR-29a-3p and Atrial Natriuretic Peptide (ANP) were performed by the method of fluorescence quantitative PCR, in addition, expression of Drp1 in treated and control groups were performed by western blot analysis.] Results: We found NPY leads to the CH and up-regulation of ANP expression levels. We also found significant up-regulation of Drp1 expression and down-regulation of miR-29a-3p expression in NPY-treated cells. The decrease in miR-29a-3p expression may lead the increase expression level of Drp1. We found that the expression of ANP increased after NPY treatment. When Drp1 protein was silenced, the high expression of ANP was inhibited. In this study, we found up-regulation of Drp1 in cells treated with NPY. Drp1 mRNA is a predicted target for miR-29a-3p, and the expression of Drp1 was attenuated by miR-29a-3p. Therefore, NPY leads to down-regulation of miR-29a-3p expression, up-regulation of Drp1 expression, and NPY leads to CH. Correspondingly, miR-29a-3p can counteract the effects of NPY. This may be a new way, which could be used in diagnosis and treatment plan for CH.

A Randomized Controlled Trial of Intranasal Neuropeptide Y in Patients With Major Depressive Disorder.

BackgroundSince about one-third of patients with major depressive disorder (MDD) do not respond adequately to available antidepressants, there is a need for treatments based on novel mechanisms of action. Neuropeptide Y (NPY), a normal brain constituent, is reduced in cerebrospinal fluid of patients with MDD and post-traumatic stress disorder and in corresponding rodent models. Moreover, NPY administered centrally or intranasally rescues pathophysiology in these models. Consequently, we conducted the first, to our knowledge, controlled trial of NPY as a treatment for MDD.MethodsThirty MDD patients on a stable dose of a conventional antidepressant insufflated 6.8 mg NPY (n = 12) or placebo (n = 18) in a double blind randomized fashion. Effects were assessed at baseline, +1 hour, +5 hours, +24 hours, and +48 hours. The primary outcome was change in depression severity measured with the Montgomery-Åsberg Depression Rating Scale (MADRS).ResultsNPY was superior to placebo at +24 hours (change −10.3 [95% CI: −13.8; −6.8]) vs −5.6 (95% CI: −8.4; −2.7); group*time F = 3.26, DF = (1,28), P = .04; Cohen’s d = 0.67). At +5 hours MADRS decreased −7.1 ([95% CI: −10.0; −4.2] vs −3.5 [95% CI: −5.8; −1.2]; group*time F = 2.69, DF = (1,28), P = .05; Cohen’s d = 0.61). MADRS reduction at +48 hours was not significant.ConclusionsSince no results regarding the trajectory of NPY effects existed prior to this study we extrapolated from the known NPY biology and predicted the effects will occur 5–48 hours post insufflation. We chose +48 hours as the primary endpoint and +1, +5, and +24 hours as secondary endpoints. The results, the first of their kind, indicate that insufflated NPY is antidepressant, despite not meeting the primary outcome, and call for dose ranging and repeated NPY insufflation trials.Clinical Trial RegistrationEudraCT Number: 2014-000129-19.

Protective effect of neuropeptide Y2 receptor activation against methamphetamine-induced brain endothelial cell alterations

Methamphetamine (METH) consumption is a health problem that leads to neurological and psychiatric disturbances. The cellular alterations behind these conditions have been extensively investigated and it is now well-established that METH causes cerebrovascular alterations being a key feature in drug-induced neuropathology.Although promising advances in understanding the blood-brain barrier (BBB) alterations induced by METH, there is still no available approach to counteract or diminish such effects. Interestingly, several studies show that neuropeptide Y (NPY) has an important protective role against METH-induced neuronal and glial toxicity, as well as behavioral deficits. Despite these beneficial effects of the NPY system, nothing is known about its role in brain endothelial cells under conditions of METH exposure.Thus, our aim was to unravel the effect of NPY and its receptors against METH-induced endothelial cell dysfunction. For that, we used a human brain microvascular endothelial cell line (hCMEC/D3) and our results demonstrate that endothelial cells express both NPY Y1 (Y1R) and Y2 (Y2R) receptors, but only Y2R is upregulated after METH exposure. Moreover, this drug of abuse induced endothelial cell death and elicited the production of reactive oxygen species (ROS) by these cells, which were prevented by the activation of Y2R. Additional, cell death and oxidative stress triggered by METH were dependent on the concentration of the drug. In sum, with the present study we identified for the first time the NPY system, and particularly the Y2R subtype, as a promising target to protect against METH-induced neurovascular dysfunction.

Abstract 5168: The dual regulatory role of Neuropeptide Y in colon cancer

Abstract Introduction: Colon cancer is the third most common cancer and affects approximately one million people every year. Patients with inflammatory bowel diseases (IBDs) have a higher risk of developing colon cancer. The neuropeptides, particularly neuropeptide Y (NPY) which is a 36-amino acid neuropeptide found in the brain, the autonomic nervous system and different peripheral tissues including the colon is associated with the development and progression of IBD. Objective: The objective of this study was to determine the role of NPY in colon cancer and establish NPY and its receptors as new targets for colon cancer. Methods: Immunohistochemical analysis was performed to detect the expression of NPY in colon cancer. Colon cancer (CT26) bearing mice were treated with both NPY Y1 receptor (Y1R) (BIBO 3304) or Y2 receptor (Y2R) (BIIE0246) specific antagonists and the effect on tumor growth and progression was studied. In vitro tumor and endothelial cell proliferation assays and colonic endothelial cell (CEC) migration and tubule forming assays were also conducted. Results and Conclusion: Our results show that there is significant upregulation of NPY in colon cancer and NPY is profusely secreted by colonic epithelial cells. Treatment of CT26 tumor bearing mice with both Y1R and Y2R antagonists resulted in significant reduction of tumor growth. Treatment with Y1R antagonist was associated with reduced number of proliferative cells in tumor tissues, while Y2R antagonist treated tumor tissues showed significant reduction in angiogenesis (micro vessel density). However, tumor cell apoptosis was significantly increased in both the treated groups compared to vehicle treated control group. Our in vitro results showed that treatment with NPY (100nM) significantly increased CT26 tumor cell as well as CEC proliferation compared to respective untreated control cells. However, when CT26 tumor cells were previously treated with Y1R antagonist (1μM) the effect of NPY was abrogated. Y2R antagonist (1μM) prior treated tumor cells didn't show any significant reduction in NPY induced tumor cell proliferation. On the contrary, when CEC were prior treated with Y2R antagonist, NPY mediated CEC proliferation was abrogated. Prior treatment with Y1R antagonist had no effect on this function of NPY. NPY also promoted migration and tube formation capabilities of CEC. Prior treatment with Y2R antagonist also significantly decreased these NPY mediated functions of CEC. Y1 antagonist had no effect on CEC. Our results thus show that NPY by acting through Y1 receptors, which are predominantly expressed by tumor cells, controls the proliferation and growth of the cancer cells. Also, NPY by acting through Y2 receptors that are mostly expressed by the endothelial cells controls the functions of these cells present in the tumor microenvironment. This to our knowledge is the first report about the dual regulatory role of NPY in colon cancer by which it controls both the tumor cells as well as the endothelial cells in the surrounding microenvironment. Citation Format: Sandeep Goswami, Debanjan Chakroborty, Sujit Basu, Wendy Frankel, Chandrani Sarkar. The dual regulatory role of Neuropeptide Y in colon cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5168.

Abstract 6157: Hypoxia increases motility of neuroblastoma cells induced by the neuropeptide Y/Y5 receptor pathway and exacerbates their metastatic potential

Abstract Neuroblastoma (NB) is a pediatric malignancy that originates from precursors of sympathetic neurons and expresses neuronal proteins, such as neuropeptide Y (NPY) and its receptors. NB cells constitutively express NPY Y2 receptor (Y2R), which maintains their proliferation and tumor vascularization. However, pro-apoptotic conditions additionally induce expression of Y5 receptor (Y5R), which acts as a survival factor for tumor cells. High Y5R expression was also observed in angioinvasive NB cells surrounding blood vessels, suggesting a role for this receptor in NB dissemination. Indeed, in NB patients, high serum levels of NPY associated with the presence of metastases. Hence, the goal of this study was to identify mechanisms that may underlie potential pro-metastatic effects of NPY. We have found that NPY, acting via Y5R, stimulates NB cell motility and acts as a chemotactic factor for these cells in a concentration-dependent manner. Hypoxia, a known condition promoting metastasis, increased expression of Y5R in SK-N-BE(2) and SK-N-AS NB cell lines. Consequently, hypoxic NB cells had increased motility and a chemotactic response to NPY. This increase in NPY-driven migration was fully blocked by Y5R antagonist. Pre-incubation of NB cells in hypoxia before orthotopic injections into adrenal glands of SCID/bg mice exacerbated metastasis in xenografts from both NB cell lines. In mice bearing non-MYCN amplified SK-N-AS tumors, the hypoxia-driven metastases were located in soft tissues, while MYCN-amplified SK-N-BE(2) xenografts derived from hypoxic cells exhibited enhanced dissemination to lungs. The latter pattern of metastases is also observed in NB patients with MYCN amplification. Further studies are required to determine if the hypoxia-driven increase in NB metastasis is Y5R-dependent. Altogether, our data support the role of tumor hypoxia and NPY/Y5R axis in NB dissemination. Since this pathway is also activated during chemotherapy and promotes NB cells resistance to treatment, NPY/Y5R may also be involved in the secondary dissemination of the recurrent tumors. If the role of Y5R in NB metastasis is validated in preclinical models, this NPY receptor may become a potential therapeutic target preventing the disease dissemination. Citation Format: Nouran Abualsaud, Lindsay Caprio, Sung Hyeok Hong, Susana Galli, Joanna Kitlinska. Hypoxia increases motility of neuroblastoma cells induced by the neuropeptide Y/Y5 receptor pathway and exacerbates their metastatic potential [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6157.

Pathogenic or protective? Neuropeptide Y in amyotrophic lateral sclerosis.

Neuropeptide Y (NPY) is an endogenous peptide of the central and enteric nervous systems which has gained significant interest as a potential neuroprotective agent for treatment of neurodegenerative disease. Amyotrophic lateral sclerosis (ALS) is an aggressive and fatal neurodegenerative disease characterized by motor deficits and motor neuron loss. In ALS, recent evidence from ALS patients and animal models has indicated that NPY may have a role in the disease pathogenesis. Increased NPY levels were found to correlate with disease progression in ALS patients. Similarly, NPY expression is increased in the motor cortex of ALS mice by end stages of the disease. Although the functional consequence of increased NPY levels in ALS is currently unknown, NPY has been shown to exert a diverse range of neuroprotective roles in other neurodegenerative diseases; through modulation of potassium channel activity, increased production of neurotrophins, inhibition of endoplasmic reticulum stress and autophagy, reduction of excitotoxicity, oxidative stress, neuroinflammation and hyperexcitability. Several of these mechanisms and signalling pathways are heavily implicated in the pathogenesis of ALS. Therefore, in this review, we discuss possible effects of NPY and NPY-receptor signalling in the ALS disease context, as determining NPY's contribution to, or impact on, ALS disease mechanisms will be essential for future studies investigating the NPY system as a therapeutic strategy in this devastating disease.

Effects of Neuropeptide Y administration into the lateral hypothalamus on intake of free-choice high-fat high-sucrose diet components of the male Wistar rat

ABSTRACT Introduction: Neuropeptide Y (NPY) signaling in the brain plays an important role in energy regulation, and is altered during diet-induced obesity. Yet, NPY function during the consumption of specific diet components remains to be fully determined. We have previously demonstrated that consumption of a saturated fat component (free-choice high-fat; fcHF), a sucrose solution (high-sugar; fcHS), or both (fcHFHS) combined with a standard diet (chow and water) has diverse effects on Npy expression in the arcuate nucleus and the sensitivity to intraventricular NPY administration. Arcuate NPY neurons project to the lateral hypothalamus (LHA), and NPY administration in the LHA potently promotes chow intake in rats on a standard diet. However, it is currently unclear if short-term consumption of a palatable free-choice diet alters NPY function in the LHA. Therefore, we assessed the effects of intra-LHA NPY administration on intake in rats following one-week consumption of a fcHF, fcHS, or fcHFHS diet. Methods: Male Wistar rats consumed a fcHF, fcHS, fcHFHS, or control (CHOW) diet for one week before NPY (0.3 μg / 0.3 μL) or phosphate-buffered saline (0.3 μL) was administered into the LHA. Intake was measured 2h later. fcHFHS-fed rats were divided into high-fat (fcHFHS-hf) and low-fat (fcHFHS-lf) groups based on differences in basal fat intake. Results: Intra-LHA NPY administration increased chow intake in fcHFHS- (irrespective of basal fat intake), fcHF- and CHOW-fed rats. Intra-LHA NPY infusion increased fat intake in fcHF-, fcHFHS-hf, but not fcHFHS-lf, rats. Intra-LHA NPY infusion did not increase caloric intake in fcHS-fed rats. Discussion: Our data demonstrate that the effects of intra-LHA NPY on caloric intake differ depending on the consumption of a fat or sugar component, or both, in a free-choice diet. Our data also indicate that baseline preference for the fat diet component modulates the effects of intra-LHA NPY in fcHFHS-fed rats.

Inflammation changes the expression of neuropeptide Y receptors in the pig myometrium and their role in the uterine contractility.

In the experiment the influence of inflammation on neuropeptide Y (NPY) receptor subtype 1 (Y1Rs) and 2 (Y2Rs) expression pattern in the gilt myometrium and NPY effect alone or with Y1Rs and Y2Rs antagonists on contractility of an inflamed uterus were recognized. On Day 3 of the estrous cycle, either E.coli suspension (E.coli group) or saline (SAL group) were administered into uterine horns. In the control gilts (CON group), only laparotomy was carried out. Eight days later, E.coli treatment evoked severe acute endometritis, significantly reduced Y1Rs mRNA and protein expression and increased Y2Rs protein expression in myometrium in relation to the CON and SAL groups. Compared to period before NPY application, NPY (10−7 M) significantly reduced amplitude in myometrium and endometrium/myometrium and frequency in myometrium of the CON and SAL groups and amplitude in endometrium/myometrium and frequency in strips of the E.coli group. In this group, after using NPY (10−7 M), the amplitude rose significantly in both kinds of strips, while frequency fell in endometrium/myometrium in relation to the SAL group. In the CON and SAL groups, NPY (10−7 M) with Y1Rs antagonist significantly increased the amplitude in endometrium/myometrium, while with Y2Rs antagonist caused a rise in myometrium. In the E.coli group after using Y1Rs or Y2Rs antagonist and NPY (10−7 M) amplitude did not significantly change in endometrium/myometrium, and this parameter was significantly lower after using the NPY and Y1Rs antagonist than in other groups. Y1Rs antagonist and NPY (10−8, 10−7 M) significantly increased frequency in endometrium/myometrium of the CON and SAL groups. In the E.coli group, Y1Rs or Y2Rs antagonists and NPY (10−7 M) significantly increased frequency in myometrium and it was significantly higher than in the CON group. Inflammation changes Y1Rs and Y2Rs expression in myometrium of the inflamed pig uterus and NPY reduces this organ contractility by Y1Rs and Y2Rs.

Neuropeptide Y prolongs non-social memory in a brain region- and receptor-specific way in male mice

Neuropeptide Y (NPY) and its receptors are highly expressed in brain regions involved in learning and memory processes. We have previously shown that intracerebroventricular administration of NPY prolongs the retention of non-social memory in the object discrimination test. Here, we aimed to identify the brain regions which mediate these memory-enhancing effects of NPY. We show that NPY (0.1 nmol/0.2 μl/side) prolongs retention of non-social memory when administered into the dorsolateral septum (DLS) and medial amygdala (MeA), but not when administered into the dorsal hippocampus, central amygdala and basolateral amygdala. In the DLS, the effects of NPY were blocked by the Y1 receptor antagonist BIBO3304 trifluoroacetate (0.2 nmol/0.2 μl/side), but not by the Y2 receptor antagonist BIIE0246 (0.2 nmol/0.2 μl/side). In the MeA, on the other hand, BIIE0246, but not BIBO3304 trifluoroacetate blocked the effects of NPY. This study demonstrates that NPY exerts Y1 receptor-mediated memory-enhancing effects in the DLS and Y2 receptor-mediated memory-enhancing effects in the MeA, and suggests that distinct brain regions and receptor subtypes are recruited to mediate the effects of NPY on non-social memory.

Modulation of neuropeptide Y levels is impaired in crack withdrawal patients.

Introduction The dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has a key role in drug addiction susceptibility. In addition to the well-known relationship between cortisol and the HPA axis, other molecules are involved with stress response and could modify the HPA activation, such as the neuropeptide Y (NPY), which has anxiolytic proprieties. There are few studies evaluating the effect of NPY levels on addiction, especially in crack cocaine dependence. Objective To evaluate NPY in crack users during early withdrawal to determine its relationship with drug use and cortisol levels. Methods We analyzed 25 male inpatient crack users. Serum NPY levels were measured at admission and discharge (mean of 24 days). Morning salivary cortisol was measured at admission. Results Serum NPY levels at admission and discharge were very similar. Lower NPY levels at discharge were associated with higher lifetime crack use. Also, a negative correlation was found between morning cortisol and delta NPY (NPY discharge - NPY admission). Conclusion These preliminary findings indicate that crack use influences the modulation of NPY levels and modifies stress response. The NPY pathway may play an important role in the pathophysiology of crack addiction, and the anxiolytic effect of NPY may be impaired in crack users. Future studies should consider NPY as a measurable indicator of the biological state in addiction.

Neuropeptide Y1 receptor antagonist promotes osteoporosis and microdamage repair and enhances osteogenic differentiation of bone marrow stem cells via cAMP/PKA/CREB pathway

Osteoporosis is a common metabolic bone disorder in the elderly population. The accumulation of bone microdamage is a critical factor of osteoporotic fracture. Neuropeptide Y (NPY) has been reported to regulated bone metabolism through Y1 receptor (Y1R). In this study the effects and mechanisms of Y1R antagonist on prevention for osteoporosis were characterized. In the clinical experiment, compared with osteoarthritis (OA), osteoporosis (OP) showed significant osteoporotic bone microstructure and accumulation of bone microdamage. NPY and Y1R immunoreactivity in bone were stronger in OP group, and were both correlated with bone volume fraction (BV/TV). In vivo experiment, Y1R antagonist significantly improved osteoporotic microstructure in the ovariectomized (OVX) rats. And Y1R antagonist promoted RUNX2, OPG and inhibit RANKL, MMP9 in bone marrow. In vitro cell culture experiment, NPY inhibited osteogenesis, elevated RANKL/OPG ratio and downregulated the expression of cAMP, p-PKAs and p-CREB in BMSCs, treated with Y1R antagonist or 8-Bromo-cAMP could inhibit the effects of NPY. Together, Y1R antagonist improved the bone microstructure and reduced bone microdamage in OVX rats. NPY-Y1R could inhibit osteoblast differentiation of BMSCs via cAMP/PKA/CREB pathway. Our findings highlight the regulation of NPY-Y1R in bone metabolism as a potential therapy strategy for the prevention of osteoporosis and osteoporotic fracture.

Sevoflurane Induces Hippocampal Neuronal Apoptosis by Altering the Level of Neuropeptide Y in Neonatal Rats.

Numerous studies have shown that the inhaled general anesthetic sevoflurane imposes toxicity on the central nervous system during the developmental period but the underlying mechanisms remain unclear. Neuropeptide Y (NPY) was reported to have important neuroprotective effects, which can attenuate neuronal loss under pathological conditions. However, the effects of NPY on sevoflurane-induced hippocampal neuronal apoptosis have not been investigated. In this study, postnatal day 7 (PND7) Sprague-Dawley rats and primary cultured cells separated from hippocampi were exposed to sevoflurane (2.4% for 4h) and the NPY expression levels after treatment were analyzed. Furthermore, neuronal apoptosis assay was conducted via immunofluorescence staining of cleaved caspase-3 and flow cytometry after exogenous NPY administration to PND7 rats as well as cultured hippocampal neurons to elucidate the role of NPY in sevoflurane-induced neurotoxicity. Our results showed the level of NPY gradually decreased within 24h after sevoflurane exposure in both the hippocampus of PND7 rats and cultured hippocampal neurons, but not in cultured astrocytes. In the exogenous NPY pretreatment study, the proportion of cleaved caspase-3 positive cells in the CA1 region of the hippocampus was increased significantly at 24h after sevoflurane treatment, while NPY pretreatment could reduce it. Similarly, NPY could also reverse the apoptogenic effect of sevoflurane on cultured neurons. Herein, our results showed that sevoflurane caused a significant decrease in NPY expression, whereas exogenous NPY supplementation could reduce sevoflurane-induced hippocampal neuronal apoptosis both in vivo and in vitro.

Central injection of neuropeptide Y modulates sexual behavior in male rats: interaction with GnRH and kisspeptin/neurokinin B/dynorphin

Aims A number of studies have shown that neuropeptide Y (NPY) is considered to be one of the key regulators of hypothalamic-pituitary-gonadal (HPG) axis in the mammals. In addition, kisspeptin (encode by Kiss1 gene), neurokinin B (encode by Tac3 gene) and dynorphin (encode by Pdyn gene) (commonly known as KNDy secreting neurons) are a powerful upstream regulators of GnRH neuron in hypothalamus. Materials and Methods The present study aims to investigate the effects of the intracerebroventricular (icv) injection of NPY and BIBP3226 (NPY receptor antagonist (NPYRA)) on the male sexual behavioral. Additionally, in order to see whether NPY signals can be relayed through the pathway of kisspeptin/neurokinin B/dynorphin, the gene expression of these peptides along with Gnrh1 gene in the hypothalamus were measured. Results The icv injection of NPY decreased the latencies and increase the frequencies of sexual parameters of the male rats in a significant way. In this line, NPYRA antagonized the stimulative effects of NPY. Moreover, data from real-time quantitative PCR indicated that injection of NPY significantly increased the gene expression of Gnrh1, Kiss1 and Tac3 and decrease the Pdyn while treatment with NPYRA controlled the modulative effects of NPY on these gene expression. Conclusions In conclusion based on the results of this study, NPY can exert its impacts on the sexual behavior of male rats via modulation of the KNDy secreting neurons as an interneural pathway to GnRH neurons.

Disappearance of the inhibitory effect of neuropeptide Y within the dorsolateral bed nucleus of the stria terminalis in rats with chronic pain

We recently showed that the mesolimbic dopaminergic system was tonically suppressed during chronic pain by enhanced corticotropin releasing factor (CRF) signaling within the dorsolateral bed nucleus of the stria terminalis (dlBNST), and that inhibition of intra-dlBNST CRF signaling restored the mesolimbic dopaminergic system function. Specifically, bilateral intra-dlBNST injections of the CRF type 1 receptor antagonist NBI27914 increased intra-nucleus accumbens dopamine release and induced reward-related behaviors in rats with chronic pain. Here, we used a conditioned place preference (CPP) test to explore whether intra-dlBNST injections of neuropeptide Y (NPY) restored the mesolimbic reward system function in chronic pain rats, because we previously showed that NPY had an effect opposite to that of CRF in dlBNST neurons. Specifically, CRF depolarized type II dlBNST neurons whereas NPY hyperpolarized them. However, unexpectedly, intra-dlBNST NPY injections had no effect on CPP test outcomes. Then, we compared the effects of NPY on the membrane potentials of type II dlBNST neurons of sham-operated control rats and those of chronic pain animals. Whole-cell patch-clamp electrophysiology revealed that NPY hyperpolarized type II dlBNST neurons in the sham-operated group. By contrast, in the chronic pain group, NPY did not hyperpolarize, but rather depolarized, type II dlBNST neurons. These results indicate that NPY no longer hyperpolarizes type II dlBNST neurons in rats with chronic pain, therefore it does not reverse the excitatory effects of CRF. This may be why intra-dlBNST injections of NPY into chronic pain rats did not exhibit a rewarding effect in the CPP test, whereas intra-dlBNST injections of NBI27914 did. This is the first study to demonstrate a chronic pain-induced neuroplastic change in NPY signaling in the dlBNST. Such a change may be involved in the dysfunction of the mesolimbic reward system under the chronic pain condition.

Single Prolonged Stress Provokes Depressive‐like Behavior, Anxiety and Impaired Social Interaction in Females with Potential for Early Invention with Neuropeptide Y

Sex contributes to susceptibility of stress‐elicited disorders. Women are at nearly double the risk for developing symptoms of post‐traumatic stress disorder (PTSD), depression, anxiety disorders, and social anxiety or phobia. Despite the higher prevalence of these stress‐triggered disorders, animal models, including the single prolonged stress (SPS) PTSD rodent model, and novel therapies for them are largely understudied in females. Previous studies in males indicate that neuropeptide Y (NPY) has therapeutic potential for stress‐elicited disorders; however none examine its effects in females. Here, we evaluated behavioral manifestations in terms of depressive‐like behavior, anxiety, social interaction, and episodic‐like memory and changes in gene expression in the noradrenergic system in the brain after SPS in females. In addition, we examined the potential therapeutic effects of NPY for these behavioral impairments. Females were exposed to SPS and were immediately infused with intranasal NPY or vehicle in three separate experiments. (1) Stressed females treated with 150μg NPY or vehicle were compared to unstressed controls on forced swim test (FST) and for levels of expression of several genes in the locus coeruleus (LC) 12 days after SPS exposure. (2) We examined stressed females treated with 300μg NPY or vehicle and unstressed controls on the elevated plus maze (EPM) and LC gene expression 7 days after SPS stressors. (3) We evaluated stressed females treated with 600μg NPY or vehicle and unstressed controls on the open field (OF), novel object recognition (NOR), social interaction (SI), and EPM at 7, 13, 19, and 21 days after SPS stressors, respectively. SPS led to increased depressive‐like behavior on the FST and anxiety‐like behavior on the OF and EPM, as well as impaired social interaction. Following FST, the rats displayed elevated tyrosine hydroxylase (TH), CRHR1 and Y1R mRNA levels in the LC, consistent with increased activation of the noradrenergic system. The expression level of these mRNAs was unchanged following EPM, except for Y1R. A higher dose of intranasal NPY tended to have larger anxiolytic effects than the lower dose, however unlike in previously tested males neither dose was significantly different from vehicle. Intranasal NPY did significantly prevent impaired social interaction, as compared to vehicle. There was no effect of SPS or NPY on impairment of memory on the NOR. The results indicate that SPS appropriately elicits PTSD associated behavior and molecular impairments in females. Intranasal NPY has potential for therapeutic intervention with important sex‐specific differences.Support or Funding InformationU.S. Department of Defense (DOD) Award No. W81XWH‐16‐1‐0016 and New York Medical College (NYMC)/Touro Bridge Funding Program 49‐506.

Contribution of NPY Y5 Receptors to the Reversible Structural Remodeling of Basolateral Amygdala Dendrites in Male Rats Associated with NPY-Mediated Stress Resilience.

Endogenous neuropeptide Y (NPY) and corticotrophin-releasing factor (CRF) modulate the responses of the basolateral amygdala (BLA) to stress and are associated with the development of stress resilience and vulnerability, respectively. We characterized persistent effects of repeated NPY and CRF treatment on the structure and function of BLA principal neurons in a novel organotypic slice culture (OTC) model of male rat BLA, and examined the contributions of specific NPY receptor subtypes to these neural and behavioral effects. In BLA principal neurons within the OTCs, repeated NPY treatment caused persistent attenuation of excitatory input and induced dendritic hypotrophy via Y5 receptor activation; conversely, CRF increased excitatory input and induced hypertrophy of BLA principal neurons. Repeated treatment of OTCs with NPY followed by an identical treatment with CRF, or vice versa, inhibited or reversed all structural changes in OTCs. These structural responses to NPY or CRF required calcineurin or CaMKII, respectively. Finally, repeated intra-BLA injections of NPY or a Y5 receptor agonist increased social interaction, a validated behavior for anxiety, and recapitulated structural changes in BLA neurons seen in OTCs, while a Y5 receptor antagonist prevented NPY's effects both on behavior and on structure. These results implicate the Y5 receptor in the long-term, anxiolytic-like effects of NPY in the BLA, consistent with an intrinsic role in stress buffering, and highlight a remarkable mechanism by which BLA neurons may adapt to different levels of stress. Moreover, BLA OTCs offer a robust model to study mechanisms associated with resilience and vulnerability to stress in BLA.SIGNIFICANCE STATEMENT Within the basolateral amygdala (BLA), neuropeptide Y (NPY) is associated with buffering the neural stress response induced by corticotropin releasing factor, and promoting stress resilience. We used a novel organotypic slice culture model of BLA, complemented with in vivo studies, to examine the cellular mechanisms associated with the actions of NPY. In organotypic slice cultures, repeated NPY treatment reduces the complexity of the dendritic extent of anxiogenic BLA principal neurons, making them less excitable. NPY, via activation of Y5 receptors, additionally inhibits and reverses the increases in dendritic extent and excitability induced by the stress hormone, corticotropin releasing factor. This NPY-mediated neuroplasticity indicates that resilience or vulnerability to stress may thus involve neuropeptide-mediated dendritic remodeling in BLA principal neurons.

Treatment of diabetic retinopathy through neuropeptide Y-mediated enhancement of neurovascular microenvironment.

Diabetic retinopathy (DR) is one of the most severe clinical manifestations of diabetes mellitus and a major cause of blindness. DR is principally a microvascular disease, although the pathogenesis also involves metabolic reactive intermediates which induce neuronal and glial activation resulting in disruption of the neurovascular unit and regulation of the microvasculature. However, the impact of neural/glial activation in DR remains controversial, notwithstanding our understanding as to when neural/glial activation occurs in the course of disease. The objective of this study was to determine a potential protective role of neuropeptide Y (NPY) using an established model of DR permissive to N‐methyl‐D‐aspartate (NMDA)‐induced excitotoxic apoptosis of retinal ganglion cells (RGC) and vascular endothelial growth factor (VEGF)‐induced vascular leakage. In vitro evaluation using primary retinal endothelial cells demonstrates that NPY promotes vascular integrity, demonstrated by maintained tight junction protein expression and reduced permeability in response to VEGF treatment. Furthermore, ex vivo assessment of retinal tissue explants shows that NPY can protect RGC from excitotoxic‐induced apoptosis. In vivo clinical imaging and ex vivo tissue analysis in the diabetic model permitted assessment of NPY treatment in relation to neural and endothelial changes. The neuroprotective effects of NPY were confirmed by attenuating NMDA‐induced retinal neural apoptosis and able to maintain inner retinal vascular integrity. These findings could have important clinical implications and offer novel therapeutic approaches for the treatment in the early stages of DR.

Neuropeptide Y Acts Directly on Cartilage Homeostasis and Exacerbates Progression of Osteoarthritis Through NPY2R.

Neuropeptide Y (NPY) is known to regulate bone homeostasis; however, its functional role as a risk factor during osteoarthritis (OA) remains elusive. In this study, we aim to investigate the direct effect of NPY on degradation of cartilage and progression of OA and explore the molecular events involved. NPY was overexpressed in human OA cartilage accompanied with increased expression of NPY1 receptor (NPY1R) and NPY2 receptor (NPY2R). Stressors such as cold exposure resulted in the peripheral release of NPY from sympathetic nerves, which in turn promoted upregulation of NPY and NPY2R in articular cartilage in vivo. Intra-articular administration of NPY significantly promoted chondrocyte hypertrophy and cartilage matrix degradation, with a higher OARSI score than that of control mice, whereas inhibition of NPY2R but not NPY1R with its specific antagonist remarkably ameliorated NPY-mediated effects. Moreover, NPY activated mTORC1 pathway in articular chondrocytes, whereas the administration of rapamycin (an mTORC1 inhibitor) in vitro abrogated NPY-mediated effects. Mechanistically, mTORC1 downstream kinase S6K1 interacted with and phosphorylated SMAD1/5/8 and promoted SMAD4 nuclear translocation, resulting in upregulation of Runx2 expression to promote chondrocyte hypertrophy and cartilage degradation. In conclusion, our findings provided the direct evidence and the crucial role of NPY in cartilage homeostasis. © 2020 American Society for Bone and Mineral Research.

Neuropeptide regulation of secretion and inflammation in human airway gland serous cells.

Airway submucosal gland serous cells are sites of expression of the cystic fibrosis transmembrane conductance regulator (CFTR) and are important for fluid secretion in conducting airways. To elucidate how neuropeptides regulate serous cells, we tested if human nasal turbinate serous cells secrete bicarbonate (HCO3 -), important for mucus polymerisation and antimicrobial peptide function, during stimulation with cAMP-elevating vasoactive intestinal peptide (VIP) and if this requires CFTR. Serous cells stimulated with VIP exhibited a ∼15-20% cAMP-dependent decrease in cell volume and a ∼0.15 unit decrease in intracellular pH (pHi), reflecting activation of Cl- and HCO3 - secretion, respectively. HCO3 - secretion was directly dependent on CFTR and was absent in cells from CF patients. In contrast, neuropeptide Y (NPY) reduced VIP-evoked cAMP increases, CFTR activation, and Cl-/HCO3 - secretion. Culture of primary serous cells in a model that maintained a serous phenotype confirmed the activating and inhibiting effects of VIP and NPY, respectively, on fluid and HCO3 - secretion. Moreover, VIP enhanced antimicrobial peptide secretion and antimicrobial efficacy of secretions while NPY reduced antimicrobial efficacy. In contrast, NPY enhanced cytokine release while VIP reduced cytokine release through a mechanism requiring CFTR. As levels of VIP and NPY are up-regulated in diseases like allergy, asthma, and chronic rhinosinusitis, the balance of these two peptides in the airway may control mucus rheology and inflammatory responses in serous cells. Furthermore, the loss of CFTR conductance in serous cells may contribute to CF pathophysiology by increasing serous cells inflammatory responses in addition to directly impairing Cl- and HCO3 - secretion.

Neuropeptide Y enhances proliferation and chondrogenic differentiation of ATDC5 cells

In recent years, emerging evidence has illustrated the indispensable role of sympathetic neurotransmitters and their receptors in cartilage mediation. The presence of neuropeptide Y (NPY)-positive sympathetic nerve fibres in cartilage and NPY-secretion function in chondrocytes raises the possibility of NPY directly regulating the function of chondrocytes. Therefore, this study intended to evaluate the effect of NPY and its receptors on the proliferation and chondrogenic differentiation of ATDC5 cells. Results showed NPY, especially at a concentration of 10−10 M, to significantly enhance proliferation of ATDC5 cells. Moreover, NPY effectively facilitated early chondrogenesis and late hypertrophy/mineralisation of ATDC5 cells via Y1 receptor signalling, rather than via Y2 receptor signalling. Taken together, the results help us to understand how NPY and its receptors affect the function of chondrocytes.