RESUMEN
PACAP is a neuropeptide with diverse functions in various organs, including reproductive system. It is present in the testis in high concentrations, and in addition to the stage-specific expression within the seminiferous tubules, PACAP affects spermatogenesis and the functions of Leydig and Sertoli cells. Mice lacking endogenous PACAP show reduced fertility, but the possibility of abnormalities in spermatogenic signaling has not yet been investigated. Therefore, we performed a detailed morphological analysis of spermatozoa, sperm motility and investigated signaling pathways that play a role during spermatogenesis in knockout mice. No significant alterations were found in testicular morphology or motility of sperm in homozygous and heterozygous PACAP-deficient mice in spite of the moderately increased number of severely damaged sperms. However, we found robust changes in mRNA and/or protein expression of several factors that play an important role in spermatogenesis. Protein kinase A expression was markedly reduced, while downstream phospho-ERK and p38 were elevated in knockout animals. Expression of major transcription factors, such as Sox9 and phospho-Sox9, was decreased, while that of Sox10, as a redundant factor, was increased in PACAP-deficient mice. The reduced phospho-Sox9 expression was partly due to increased expression and activity of phosphatase PP2A in knockout mice. Targets of Sox transcription factors, such as collagen type IV, were reduced in knockout mice. In summary, our results show that lack of PACAP leads to disturbed signaling in spermatogenesis, which could be a factor responsible for reduced fertility in PACAP knockout mice, and further support the role of PACAP in reproduction.
Asunto(s)
Biomarcadores/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/fisiología , Túbulos Seminíferos/patología , Motilidad Espermática/fisiología , Espermatogénesis , Espermatozoides/patología , Animales , Masculino , Ratones , Ratones Noqueados , Proteína Fosfatasa 2/metabolismo , Reproducción , Túbulos Seminíferos/metabolismo , Espermatozoides/metabolismoRESUMEN
BACKGROUND: Since its discovery, several distinct effects of pituitary adenylate cyclase activating polypeptide (PACAP) have been established - predominantly in animal studies - in the nervous system, various peripheral organs as well as in the endocrine regulation. It is unknown whether PACAP has any effect on human pregnancy regarding either utero-maternal or perinatal aspects of the gestation. AIM: We investigated alterations of PACAP38-like immunoreactivity (PACAP38-LI) in the human plasma throughout normal pregnancy, during and after delivery, and its level in the umbilical vessels, as well as in the peripheral blood of term healthy newborns. MATERIALS AND METHODS: A 2 ml blood sample was used for each test, PACAP38-LI was determined by radioimmunoassay. RESULTS: In the 2nd and 3rd trimester significant elevation was observed in the PACAP38-LI compared to the earlier gestation and non-pregnant conditions. During delivery its level significantly decreased and returned to the original values 3 days after birth. In the neonates PACAP38-LI level of the peripheral blood was similar to that of healthy adults, but umbilical arteries and veins contained significantly lower concentrations of PACAP38-LI. Besides, the levels were lower in the umbilical vein compared to the artery. CONCLUSIONS: PACAP38-LI levels show sensitive change during normal pregnancy and delivery. Our findings suggest that the fetal organs actively synthesize PACAP. Further investigations are required to elucidate the physiological importance of the alterations observed.
Asunto(s)
Recién Nacido/sangre , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/sangre , Periodo Posparto/sangre , Embarazo/sangre , Adulto , Femenino , Humanos , Parto/sangre , Segundo Trimestre del Embarazo/sangre , Tercer Trimestre del Embarazo/sangre , Arterias Umbilicales/química , Venas Umbilicales/químicaRESUMEN
Pituitary adenylate cyclase activating polypeptide (PACAP) is involved in development and reproduction. We previously described elevated PACAP levels in the milk compared to the plasma, and the presence of its specific PAC1 receptor in the mammary gland. This study aimed to determine PACAP and vasoactive intestinal peptide (VIP) levels in female suckling lambs compared to ewe plasma and mammary gland, as well as their age-dependent alterations. mRNA expressions of PACAP, VIP, PAC1 receptor and brain-derived neurotrophic factor (BDNF) were quantified in the milk whey and mammary gland. PACAP38-like immunoreactivity (PACAP38-LI) was measured in plasma, milk whey and mammary gland by radioimmunoassay, VIP-LI by enzyme-linked immunoassay. PACAP38-LI was 5, 6 times higher in the milk compared to the plasma of lactating sheep. It significantly increased in the lamb plasma 1 h, but returned to basal level 2 h after suckling. However, VIP mRNA was not present in the mammary gland, we detected the VIP protein in the milk whey. BDNF mRNA significantly decreased with age to approximately 60% and 25% in the 3- and 10-year-old sheep respectively, compared to the 3-month-old lambs. No differences were found between mammary and jugular vein plasma PACAP and VIP concentrations, or during the daily cycle. We propose a rapid absorption of PACAP38 from the milk and/or its release in suckling lambs. PACAP accumulated in the milk might be synthesized in the mammary gland or secreted from the plasma of the mothers. PACAP is suggested to have differentiation/proliferation promoting and immunomodulatory effects in the newborns and/or a local function in the mammary gland.
Asunto(s)
Animales Recién Nacidos , Animales Lactantes/fisiología , Lactancia/fisiología , Glándulas Mamarias Animales/metabolismo , Leche/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa , Plasma/metabolismo , Péptido Intestinal Vasoactivo/metabolismo , Animales , Animales Recién Nacidos/sangre , Animales Recién Nacidos/crecimiento & desarrollo , Animales Recién Nacidos/inmunología , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Femenino , Factores Inmunológicos/análisis , Factores Inmunológicos/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/análisis , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/metabolismo , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/metabolismo , OvinosRESUMEN
Numerous studies indicate that smoking during pregnancy exerts harmful effects on fetal brain development. The aim of this study was to determine the influence of maternal smoking during pregnancy on the early physical and neurobehavioral development of newborn rats. Wistar rats were subjected to whole-body smoke exposure for 2 × 40 min daily from the day of mating until day of delivery. For this treatment, a manual closed-chamber smoking system and 4 research cigarettes per occasion were used. After delivery the offspring were tested daily for somatic growth, maturation of facial characteristics and neurobehavioral development until three weeks of age. Motor coordination tests were performed at 3 and 4 weeks of age. We found that prenatal cigarette smoke exposure did not alter weight gain or motor coordination. Critical physical reflexes indicative of neurobehavioral development (eyelid reflex, ear unfolding) appeared significantly later in pups prenatally exposed to smoke as compared to the control group. Prenatal smoke exposure also resulted in a delayed appearance of reflexes indicating neural maturity, including hind limb grasping and forelimb placing reflexes. In conclusion, clinically relevant prenatal exposure to cigarette smoke results in slightly altered neurobehavioral development in rat pups. These findings suggest that chronic exposure of pregnant mothers to cigarette smoke (including passive smoking) results in persisting alterations in the developing brain, which may have long-lasting consequences supporting the concept of developmental origins of health and disease (DoHAD).
Asunto(s)
Conducta Animal/efectos de los fármacos , Enfermedades del Sistema Nervioso/patología , Efectos Tardíos de la Exposición Prenatal/patología , Fumar/efectos adversos , Animales , Animales Recién Nacidos , Peso Corporal , Modelos Animales de Enfermedad , Femenino , Masculino , Actividad Motora/fisiología , Enfermedades del Sistema Nervioso/inducido químicamente , Embarazo , Efectos Tardíos de la Exposición Prenatal/etiología , Efectos Tardíos de la Exposición Prenatal/psicología , Ratas , Ratas Wistar , Reflejo/fisiologíaRESUMEN
Tissue injury caused by cold preservation and reperfusion during small bowel transplantation remains an unsolved problem. Increasing evidence suggests that pituitary adenylate cyclase-activating polypeptide (PACAP) has protective effects in several ischemia-reperfusion (I/R) models. This study investigated the effect of PACAP-38 on oxidative stress in autotransplanted intestine. We established sham-operated, I/R, and autotransplanted groups in Wistar rats (n = 55). We applied ischemia for 1 (GI), 2 (GII), or 3 hours (GIII). In autotransplanted groups, we performed total orthotopic intestinal autotransplantation. Grafts were preserved in University of Wisconsin (UW) solution for 1 (GIV), 2 (GV), 3 (GVI), or 6 (GVII) hours and in PACAP-38-containing UW for 1 (GVIII), 2 (GIX), 3 (GX), or 6 (GXI) hours. Reperfusion lasted 3 hours in each group. Endogenous PACAP-38 values were measured by radioimmunoassay. Oxidative stress parameters malondialdehyde (MDA), reduced glutathione (GSH), and superoxide dismutase (SOD) were measured in tissue homogenates. Concentration of endogenous PACAP-38 significantly decreased in GI to GIII compared with the sham-operated animals following I/R periods (P < .05). Cold preservation in UW and reperfusion of the intestine increased the level of tissue MDA in GIV to GVII, which correlated with the duration of cold storage. The content of GSH decreased in GIV to GVII to levels that were significantly different between GIV and GVIII and between GVII and GXI. SOD activity decreased dramatically in GIV to GVII with significantly higher activity in GIX to GXI. Our findings confirmed that I/R decreased endogenous PACAP-38 concentration. Administration of PACAP-38 to UW solution mitigated the oxidative injury during intestinal autotransplantation.
Asunto(s)
Intestinos/irrigación sanguínea , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/metabolismo , Daño por Reperfusión/fisiopatología , Adenosina , Alopurinol , Animales , Frío , Glutatión/metabolismo , Insulina , Masculino , Malondialdehído/metabolismo , Preservación de Órganos/métodos , Soluciones Preservantes de Órganos , Rafinosa , Ratas , Ratas Wistar , Superóxido Dismutasa/metabolismoRESUMEN
Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase activating polypeptide (PACAP) belong to the same peptide family and exert a variety of biological functions. Both PACAP and VIP have protective effects in several tissues. While PACAP is known to be a stronger retinoprotective peptide, VIP has very potent anti-inflammatory effects. The need for a non-invasive therapeutic approach has emerged and PACAP has been shown to be retinoprotective when administered in the form of eye drops as well. The cell penetrating peptide TAT is composed of 11 amino acids and tagging of TAT at the C-terminus of neuropeptides PACAP/VIP can enhance the traversing ability of the peptides through the biological barriers. We hypothesized that TAT-bound PACAP and VIP could be more effective in exerting retinoprotective effects when given in eye drops, by increasing the traversing efficacy and enhancing the activation of the PAC1 receptor. Rats were subjected to bilateral carotid artery occlusion (BCCAO), and retinas were processed for histological analysis 14 days later. The efficiency of the TAT-bound peptides to reach the retina was assessed as well as their cAMP increasing ability. Our present study provides evidence, for the first time, that topically administered PACAP and VIP derivatives (PACAP-TAT and VIP-TAT) attenuate ischemic retinal degeneration via the PAC1 receptor presumably due to a multifactorial protective mechanism.
Asunto(s)
Antiinflamatorios/farmacología , Fármacos Neuroprotectores/farmacología , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/farmacología , Retina/efectos de los fármacos , Degeneración Retiniana/tratamiento farmacológico , Péptido Intestinal Vasoactivo/farmacología , Animales , Antiinflamatorios/administración & dosificación , Antiinflamatorios/uso terapéutico , Células CHO , Cricetinae , Cricetulus , Masculino , Fármacos Neuroprotectores/administración & dosificación , Fármacos Neuroprotectores/uso terapéutico , Soluciones Oftálmicas , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/química , Ratas , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacología , Retina/metabolismo , Péptido Intestinal Vasoactivo/química , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/genéticaRESUMEN
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with neuroprotective and neurotrophic effects. This suggests its influence on the development of teeth, which are, similarly to the nervous system, ectoderm and neural crest derivatives. Our earlier studies have shown morphological differences between wild-type (WT) and PACAP-deficient mice, with upregulated sonic hedgehog (SHH) signaling in the lack of PACAP. Notch signaling is a key element of proper tooth development by regulating apoptosis and cell proliferation. In this study, our main goal was to evaluate the possible effects of PACAP on Notch signaling pathway. Immunohistochemical staining was performed of Notch receptors (Notch1, 2, 3, 4), their ligands [delta-like protein (DLL)1, 3, 4, Jagged1, 2], and intracellular target molecules [CSL (CBF1 humans/Su (H) Drosophila/LAG1 Caenorhabditis elegans transcription factor); TACE (TNF-α converting enzyme), NUMB] in molar teeth of 5-day-old WT, and homozygous and heterozygous PACAP-deficient mice. We measured immunopositivity in the enamel-producing ameloblasts and dentin-producing odontoblasts. Notch2 receptor and DLL1 expression were elevated in ameloblasts of PACAP-deficient mice compared to those in WT ones. The expression of CSL showed similar results both in the ameloblasts and odontoblasts. Jagged1 ligand expression was elevated in the odontoblasts of homozygous PACAP-deficient mice compared to WT mice. Other Notch pathway elements did not show significant differences between the genotype groups. The lack of PACAP leads to upregulation of Notch pathway elements in the odontoblast and ameloblast cells. The underlying molecular mechanisms are yet to be elucidated; however, we propose SHH-dependent and independent processes. We hypothesize that this compensatory upregulation of Notch signaling by the lack of PACAP could represent a salvage pathway in PACAP-deficient animals.
Asunto(s)
Diente Molar/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/genética , Receptor Notch1/metabolismo , Transducción de Señal , Ameloblastos/metabolismo , Animales , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Proteína Jagged-1/genética , Proteína Jagged-1/metabolismo , Ratones , Diente Molar/citología , Diente Molar/crecimiento & desarrollo , Odontoblastos/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/deficiencia , Receptor Notch1/genética , Regulación hacia ArribaRESUMEN
The aim of this study was to show the presence, distribution and function of the pituitary adenylate cyclase activating polypeptide (PACAP) and its receptors in the CNS and peripheral nervous system of the mollusk, Helix pomatia. PACAP-like and pituitary adenylate cyclase activating polypeptide receptor (PAC1-R)-like immunoreactivity was abundant both in the CNS and the peripheral nervous system of the snail. In addition several non-neuronal cells also revealed PACAP-like immunoreactivity. In inactive animals labeled cell bodies were mainly found and in the neuropile of active animals dense immunostained fiber system was additionally detected suggesting that expression of PACAP-like peptide was affected by the behavioral state of the animal. RIA measurements revealed the existence of both forms of PACAP in the CNS where the 27 amino acid form was found to be dominant. The concentration of PACAP27 was significantly higher in samples from active animals supporting the data obtained by immunohistochemistry. In Western blot experiments PACAP27 and PACAP38 antibodies specifically labeled protein band at 4.5 kDa both in rat and snail brain homogenates, and additionally an approximately 14 kDa band in snail. The 4.5 kDa protein corresponds to PACAP38 and the 14 kDa protein corresponds to the preproPACAP or to a PACAP-like peptide having larger molecular weight than mammalian PACAP38. In matrix-assisted laser desorption ionization time of flight (MALDI TOF) measurements fragments of PACAP38 were identified in brain samples suggesting the presence of a large molecular weight peptide in the snail. Applying antibodies developed against the PACAP receptor PAC1-R, immunopositive stained neurons and a dense network of fibers were identified in each of the ganglia. In electrophysiological experiments, extracellular application of PACAP27 and PACAP38 transiently depolarized or increased postsynaptic activity of neurons expressing PAC1-R. In several neurons PACAP elicited a long lasting hyperpolarization which was eliminated after 1.5 h continuous washing. Taken together, these results indicate that PACAP may have significant role in a wide range of basic physiological functions in snail.
Asunto(s)
Conducta Alimentaria/fisiología , Caracoles Helix/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/metabolismo , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/metabolismo , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Adenilil Ciclasas/metabolismo , Secuencia de Aminoácidos , Estructuras Animales/metabolismo , Animales , Química Encefálica , Ganglios de Invertebrados/citología , Ganglios de Invertebrados/metabolismo , Hemolinfa/metabolismo , Inmunohistoquímica , Datos de Secuencia Molecular , Sistema Nervioso/química , Sistema Nervioso/citología , Sistema Nervioso/metabolismo , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/análisis , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/farmacología , Radioinmunoensayo , Ratas , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/análisis , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
The effects of pituitary adenylate cyclase activating polypeptide (PACAP) are mediated through G-protein-coupled receptors, the specific PAC1 receptor and VPAC1 and VPAC2 receptors which bind vasoactive intestinal peptide with similar affinity. Based on binding affinity studies, PACAP6-38 was discovered as a potent antagonist of PAC1 and it has been used by hundreds of studies as a PACAP antagonist. Recently, we have found that in certain cells/tissues, PACAP6-38 does not antagonize PACAP-induced effects, but surprisingly, it exerts similar actions to PACAP1-38, behaving as an agonist. In the present study, we report on the agonistic behavior of PACAP6-38 on neuropeptide release from sensory nerves of the isolated rat trachea and on the MAPK signaling pathways in cytotrophoblast cells. In isolated rat tracheae, PACAP6-38, similarly to PACAP1-38, induced significant inhibitory effects on the release of three simultaneously measured sensory neuropeptides, substance P, calcitonin gene-related peptide, and somatostatin evoked by both chemical excitation and electrical field stimulation of capsaicin-sensitive afferents. Effects of PACAP6-38 were the same as those of PACAP1-38 on MAPK signaling in human cytotrophoblast cells. Western blot analysis showed that both peptide forms stimulated ERK1/2 and JNK phosphorylation, while they both inhibited p38 MAPK phosphorylation. The most pronounced effects were observed when both peptides were present. In summary, our results show that PACAP6-38, which is a PACAP receptor antagonist in most cells/tissues, can behave as an agonist in other systems. The increasing interest in the effects of PACAP requires further studies on the pharmacological properties of the peptide and its analogues.
Asunto(s)
Fragmentos de Péptidos/farmacología , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/farmacología , Células Receptoras Sensoriales/efectos de los fármacos , Trofoblastos , Animales , Péptido Relacionado con Gen de Calcitonina/metabolismo , Capsaicina/farmacología , Línea Celular Tumoral , Humanos , Sistema de Señalización de MAP Quinasas/fisiología , Masculino , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Ratas , Ratas Wistar , Células Receptoras Sensoriales/metabolismo , Fármacos del Sistema Sensorial/farmacología , Somatostatina/metabolismo , Sustancia P/metabolismo , Técnicas de Cultivo de Tejidos , Tráquea/efectos de los fármacos , Tráquea/metabolismo , Trofoblastos/citología , Trofoblastos/efectos de los fármacosRESUMEN
The presence and pattern of pituitary adenylate cyclase activating polypeptide (PACAP) type I (PAC1) receptors were identified by means of pre- and post-embedding immunocytochemical methods in the ventral nerve cord ganglia (VNC) of the earthworm Eisenia fetida. Light and electron microscopic observations revealed the exact anatomical positions of labeled structures suggesting that PACAP mediates the activity of some interneurons, a few small motoneurons and certain sensory fibers that are located in ventrolateral, ventromedial and intermediomedial sensory longitudinal axon bundles of the VNC ganglia. No labeling was located on large interneuronal systems such as dorsal medial and lateral giant axon systems and ventral giant axons. At the ultrastructural level labeling was mainly restricted to endo- and plasma membranes showing characteristic unequal distribution in various neuron parts. An increasing abundance of PAC1 receptors located on both rough endoplasmic reticulum and plasma membranes was seen from perikarya to neural processes, indicating that intracellular membrane traffic might play a crucial role in the transportation of PAC1 receptors. High number of PAC1 receptors was found in both pre- and postsynaptic membranes in addition to extrasynaptic sites suggesting that PACAP acts as neurotransmitter and neuromodulator in the earthworm nervous system.
Asunto(s)
Ganglios/metabolismo , Ganglios/ultraestructura , Modelos Neurológicos , Oligoquetos/metabolismo , Oligoquetos/ultraestructura , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/metabolismo , Animales , Ganglios/inmunología , Inmunohistoquímica , Microscopía Inmunoelectrónica , Oligoquetos/inmunologíaRESUMEN
The neuropeptide PACAP (pituitary adenylate cyclase activating polypeptide) and its receptors are widely expressed in the nervous system and various other tissues. PACAP has well-known anti-apoptotic effects in neuronal cell lines. Recent data suggest that PACAP exerts anti-apoptotic effects also in non-neuronal cells. The peptide is present in the cardiovascular system, and has various distinct effects. The aim of the present study was to investigate whether PACAP is protective against in vitro ischemia/reperfusion-induced apoptosis in cardiomyocytes. Cultured cardiomyocytes were exposed to 60 min ischemia followed by 120 min reperfusion. The addition of PACAP1-38 significantly increased cell viability and decreased the ratio of apoptotic cells as measured by MTT test and flow cytometry. PACAP induced the phosphorylation of Akt and protein kinase A. In the present study we also examined the possible involvement of Akt- and protein kinase A-induced phosphorylation and thus inactivation of Bad, a pro-apoptotic member of the Bcl-2 family. It was found that ischemia significantly decreased the levels of phosphorylated Bad, which was counteracted by PACAP. Furthermore, PACAP increased the levels of Bcl-xL and 14-3-3 protein, both of which promote cell survival, and decreased the apoptosis executor caspase-3 cleavage. All effects of PACAP1-38 were inhibited by the PACAP antagonist PACAP6-38. In summary, our results show that PACAP has protective effects against ischemia/reperfusion-induced cardiomyocyte apoptosis and provides new insights into the signaling mechanisms involved in the PACAP-mediated anti-apoptotic effects.
Asunto(s)
Proteínas 14-3-3/metabolismo , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Daño por Reperfusión Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/patología , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/farmacología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteína Letal Asociada a bcl/metabolismo , Animales , Apoptosis/efectos de los fármacos , Células Cultivadas , Citoprotección/efectos de los fármacos , Ratas , Ratas Wistar , Transducción de Señal/efectos de los fármacosRESUMEN
Dysregulation of neuropeptides may play an important role in aging-induced impairments. In the long list of neuropeptides, pituitary adenylate cyclase-activating polypeptide (PACAP) represents a highly effective cytoprotective peptide that provides an endogenous control against a variety of tissue-damaging stimuli. PACAP has neuro- and general cytoprotective effects due to anti-apoptotic, anti-inflammatory, and antioxidant actions. As PACAP is also a part of the endogenous protective machinery, it can be hypothesized that the decreased protective effects in lack of endogenous PACAP would accelerate age-related degeneration and PACAP knockout mice would display age-related degenerative signs earlier. Recent results support this hypothesis showing that PACAP deficiency mimics aspects of age-related pathophysiological changes including increased neuronal vulnerability and systemic degeneration accompanied by increased apoptosis, oxidative stress, and inflammation. Decrease in PACAP expression has been shown in different species from invertebrates to humans. PACAP-deficient mice display numerous pathological alterations mimicking early aging, such as retinal changes, corneal keratinization and blurring, and systemic amyloidosis. In the present review, we summarize these findings and propose that PACAP deficiency could be a good model of premature aging.
Asunto(s)
Envejecimiento/fisiología , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/deficiencia , Animales , Ratones , Modelos AnimalesRESUMEN
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a well-known neuropeptide with strong neurotrophic and neuroprotective effects. PACAP exerts its protective actions via three G protein-coupled receptors: the specific Pac1 receptor (Pac1R) and the Vpac1/Vpac2 receptors, the neuroprotective effects being mainly mediated by the Pac1R. The protective role of PACAP in models of Parkinson's disease and other neurodegenerative diseases is now well-established in both in vitro and in vivo studies. PACAP and its receptors occur in the mammalian brain, including regions associated with Parkinson's disease. PACAP receptor upregulation or downregulation has been reported in several injury models or human diseases, but no data are available on alterations of receptor expression in Parkinson's disease. The model closest to the human disease is the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced macaque model. Therefore, our present aim was to evaluate changes in Pac1R expression in basal ganglia related to Parkinson's disease in a macaque model. Monkeys were rendered parkinsonian with MPTP, and striatum, pallidum, and cortex were evaluated for Pac1R immunostaining. We found that Pac1R immunosignal was markedly reduced in the caudate nucleus, putamen, and internal and external parts of the globus pallidus, while the immunoreactivity remained unchanged in the cortex of MPTP-treated parkinsonian monkey brains. This decrease was attenuated in some brain areas in monkeys treated with L-DOPA. The strong, specific decrease of the PACAP receptor immunosignal in the basal ganglia of parkinsonian macaque monkey brains suggests that the PACAP/Pac1R system may play an important role in the development/progression of the disease.
Asunto(s)
Ganglios Basales/metabolismo , Intoxicación por MPTP/patología , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/metabolismo , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina/farmacología , Análisis de Varianza , Animales , Antiparkinsonianos/uso terapéutico , Núcleo Caudado/efectos de los fármacos , Núcleo Caudado/metabolismo , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/metabolismo , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/efectos de los fármacos , Levodopa/uso terapéutico , Intoxicación por MPTP/tratamiento farmacológico , Macaca fascicularis , Masculino , Fosfopiruvato Hidratasa/metabolismo , Tirosina 3-Monooxigenasa/metabolismoRESUMEN
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide highly expressed in the central and peripheral nervous system, where it exerts several neuromodulatory functions and is an important trophic and protective factor. PACAP has been shown to activate several protective pathways, mainly through its specific PAC1 receptor and protein kinase A, C and MAP kinases downstream. It has been shown to have very potent neuroprotective actions against different neurotoxic agents both in vitro and in vivo. The aim of the present review is to provide an overview on the neurotoxic injuries against which PACAP exerts protection, and to give an insight into its protective mechanism. We give a summary of the neuroprotective effects against the most commonly used neurotoxic agents, such as 6-OHDA, MPTP, glutamate and some less well-known neurotoxic compounds. Also endogenous PACAP has neuroprotective effects, known from studies in PACAP knockout mice or from blocking endogenous effects by antagonists. Altogether, the vast amount of data for the neuroprotective effects of PACAP give a firm background for its endogenous role as part of the neuroprotective machinery and its possible future therapeutic use as a neuroprotective factor.
Asunto(s)
Fármacos Neuroprotectores/uso terapéutico , Síndromes de Neurotoxicidad/tratamiento farmacológico , Neurotoxinas/toxicidad , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/uso terapéutico , Animales , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Humanos , Síndromes de Neurotoxicidad/metabolismoRESUMEN
Traumatic brain injury (TBI) represents a leading cause of death in western countries. Despite all research efforts we still lack any pharmacological agent that could effectively be utilized in the clinical treatment of TBI. Detailed unraveling of the pathobiological processes initiated by/operant in TBI is a prerequisite to the development of rational therapeutic interventions. In this review we provide a summary of those therapeutic interventions purported to inhibit the cell death (CD) cascades ignited in TBI. On noxious stimuli three major forms of CD, apoptosis, autophagia and necrosis may occur. Apoptosis can be induced either via the mitochondrial (intrinsic) or the receptor mediated (extrinsic) pathway; endoplasmic reticular stress is the third trigger of caspase-mediated apoptotic processes. Although, theoretically pan-caspase inhibition could be an efficient tool to limit apoptosis and thereby the extent of TBI, potential cross-talk between various avenues of CD suggests that more upstream events, particularly the preservation of the cellular energy homeostasis (cyclosporine-A, poly ADP ribose polymerase (PARP) inhibition, hypothermia treatment) may represent more efficient therapeutic targets hopefully also translated to the clinical care of the severely head injured.
Asunto(s)
Apoptosis/efectos de los fármacos , Lesiones Encefálicas/terapia , Neuroglía/fisiología , Neuronas/fisiología , Animales , Apoptosis/fisiología , Humanos , Neuroglía/efectos de los fármacos , Neuronas/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiologíaRESUMEN
Inhibitory actions of pituitary adenylate cyclase activating polypeptide (PACAP) have been described on cellular/vascular inflammatory components, but there are few data concerning its role in neurogenic inflammation. In this study we measured PACAP-like immunoreactivity with radioimmunoassay in the rat plasma and showed a two-fold elevation in response to systemic stimulation of capsaicin-sensitive sensory nerves by resiniferatoxin, but not after local excitation of cutaneous afferents. Neurogenic plasma extravasation in the plantar skin induced by intraplantar capsaicin or resiniferatoxin, as well as carrageenan-induced paw edema were significantly diminished by intraperitoneal PACAP-38. In summary, these results demonstrate that PACAP is released from activated capsaicin-sensitive afferents into the systemic circulation. It diminishes acute pure neurogenic and mixed-type inflammatory reactions via inhibiting pro-inflammatory mediator release and/or by acting at post-junctional targets on the vascular endothelium.
Asunto(s)
Inflamación/sangre , Inflamación Neurogénica/sangre , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/sangre , Enfermedad Aguda , Animales , Capsaicina/administración & dosificación , Capsaicina/toxicidad , Carragenina/administración & dosificación , Carragenina/toxicidad , Diterpenos/administración & dosificación , Diterpenos/toxicidad , Edema/inducido químicamente , Edema/prevención & control , Inflamación/inducido químicamente , Inyecciones Intraperitoneales , Masculino , Espectrometría de Masas , Inflamación Neurogénica/inducido químicamente , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/administración & dosificación , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/farmacología , Radioinmunoensayo , Ratas , Ratas Wistar , Canales Catiónicos TRPV/antagonistas & inhibidoresRESUMEN
Diazoxide (DIAZ) has been shown to be neuroprotective in animal models of different brain pathologies. However, the direct protective effect of DIAZ in different in vivo models of retinal degeneration has not yet been shown. Therefore, the aim of the present study was to investigate the neuroprotective role of this compound in two rodent model systems: monosodium-glutamate (MSG)- and chronic bilateral carotid artery occlusion (BCAO)-induced retinal degeneration. Rats were subjected either to s.c. MSG treatment on postnatal days 1, 5 and 9, or to BCAO at 2 months of age, followed by intravitreal DIAZ treatment. Histological examination was carried out 14 or 21 days after treatments, respectively. MSG treatment destroyed almost the entire inner retina, with the inner nuclear and ganglion cell layers being fused. DIAZ treatment significantly ameliorated the MSG-induced retinal degeneration. BCAO led to a severe degeneration of all retinal layers, and DIAZ proved to be protective also in this model. Our results may have clinical implications in reducing glutamate-induced excitotoxicity or ischemic retinal degeneration in ophthalmic diseases.
Asunto(s)
Diazóxido/uso terapéutico , Ácido Glutámico/efectos adversos , Isquemia Miocárdica/complicaciones , Fármacos Neuroprotectores/uso terapéutico , Enfermedades de la Retina/etiología , Enfermedades de la Retina/prevención & control , Animales , Animales Recién Nacidos , Recuento de Células/métodos , Modelos Animales de Enfermedad , Interacciones Farmacológicas , Ratas , Ratas Wistar , Enfermedades de la Retina/patologíaRESUMEN
Monosodium glutamate (MSG) treatment of neonatal rodents leads to degeneration of the neurons in the arcuate nucleus, inner retinal layers and various other brain areas. It also causes various changes in the motor activity, sensory performance and learning abilities. We have previously shown that MSG treatment delays the appearance of some reflexes during neurobehavioral development and leads to temporary changes in reflex performance and motor coordination. Investigation of novelty-seeking behavior is of growing importance for its relationship with sensitivity to psychomotor stimulants. Perinatal administration of numerous toxic agents has been shown to influence novelty-seeking behavior in rats, but little is known about the influence of neonatal MSG treatment on the novelty-seeking behavior. The aim of the present study was to compare changes in locomotor, spontaneous exploratory and novelty-seeking behavior in periadolescent rats neonatally treated with MSG. Newborn rats were treated with 4 mg/g MSG subcutaneously on postnatal days 1, 3, 5, 7 and 9. Open-field behavior was tested at 2, 3, 4, 6 and 8 weeks of age. We found that MSG administration led to only temporary increases in locomotor behavior, which was more pronounced during the first few postnatal weeks, followed by a subtle hypoactivity at 2 months of age. Novelty-seeking was tested in four 5-min trials at 3 weeks of age. Trial 1 was in an empty open-field, two identical objects were placed in the arena during trial 2 and 3, and one of them was replaced to a novel object during trial 4. We found that the behavioral pattern of MSG-treated rats was the opposite in all tested signs in the novelty exploration test compared to control pups. In summary, our present study shows that neonatal MSG treatment leads to early temporary changes in the locomotor activity followed by hypoactivity at 2 months of age. Furthermore, MSG-treated rats show a markedly disturbed novelty-seeking behavior represented by altered activity when subjected to a novel object.
Asunto(s)
Conducta Exploratoria/efectos de los fármacos , Aditivos Alimentarios/farmacología , Actividad Motora/efectos de los fármacos , Glutamato de Sodio/farmacología , Factores de Edad , Análisis de Varianza , Animales , Animales Recién Nacidos , Conducta Animal/efectos de los fármacos , Femenino , Masculino , Ratas , Ratas WistarRESUMEN
Pituitary adenylate cyclase activating polypeptide (PACAP) is an endogenous neuropeptide having a widespread distribution both in the nervous system and peripheral organs including the gastrointestinal tract. It has been shown to exert actions on intestinal functions, mainly affecting glandular secretion and motility. PACAP has several different effects on cell survival depending on the cell type and the applied stimulus. Its influences on small intestinal epithelial cells are not yet elucidated, therefore the aim of the present study was to investigate the effects of PACAP on intestinal epithelial cells having high turnover (INT 407) against different harmful stimuli, such as oxidative stress, in vitro hypoxia and gamma radiation. We tested the effect of PACAP on proliferation and cell survival using MTT assay. Moreover, various cancer-related factors were evaluated by oncology array. PACAP did not influence the proliferation rate of INT 407 cells. Its cell survival-enhancing effect could be detected against oxidative stress, but not against in vitro hypoxia or gamma irradiation. Clonogenic survival assay was performed to analyze the effect of PACAP on clonogenic potential of cells exposed to gamma radiation. Surprisingly, PACAP enhanced the clone-forming ability decrease induced by irradiation. Western blot analysis of ERK1/2 phosphorylation was performed in order to obtain further information on the molecular background. Our data showed phospho-ERK1/2 suppression of PACAP in irradiated cells. Furthermore, the role of endogenous PACAP against oxidative stress was also investigated performing ADCYAP1 small interfering RNA transfection. We found significant difference in the cell vulnerability between cells undergoing silencing and cells without transfection suggesting the protective role of the endogenously present PACAP against oxidative stress in INT 407 cells. In summary, PACAP seems to be able to exert contradictory effects in INT 407 cells depending on the applied stressor, suggesting its regulatory role in the cellular household.
Asunto(s)
Células Epiteliales/fisiología , Intestino Delgado/citología , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/fisiología , Hipoxia de la Célula , Línea Celular , Proliferación Celular , Supervivencia Celular , Células Epiteliales/metabolismo , Células Epiteliales/efectos de la radiación , Rayos gamma/efectos adversos , Humanos , Estrés Oxidativo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/administración & dosificaciónRESUMEN
Substance P (SP) and calcitonin gene-related peptide (CGRP), released from capsaicin-sensitive sensory nerves induce local neurogenic inflammation, while somatostatin exerts systemic anti-inflammatory actions. The aim of the present study was to investigate the release of pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) and its effects on sensory neuropeptide release in vitro and acute neurogenic ear swelling in vivo. Capsaicin (10(-6) M) or electrical field stimulation (EFS; 40 V, 0.1 ms, 10 Hz, 120 s; 1200 impulses)-induced release of PACAP-38, SP, CGRP and somatostatin from isolated rat tracheae was measured with radioimmunoassay. Mustard oil-induced neurogenic inflammation in the mouse ear was determined with a micrometer and in the rat hind paw skin by the Evans Blue leakage technique. Capsaicin and EFS evoked 27% and more than twofold elevation of PACAP-38 release respectively, compared with the prestimulated basal values from isolated trachea preparation. Exogenously administered PACAP-38 (20-2000 nM) diminished both capsaicin- and EFS-evoked sensory neuropeptide release in a concentration-dependent manner. The maximal inhibitory effects of PACAP on capsaicin-induced substance P, CGRP and somatostatin release amounted to 75.4%, 73.3% and 90.0%, while EFS-evoked release of these peptides was 80.03%, 87.7% and 67.7%. In case of capsaicin stimulation the EC50 values for substance P, CGRP and somatostatin were 82.9 nM, 60.1 nM and 66.9 nM, respectively. When EFS was performed, these corresponding EC50 data were 92.1 nM, 67.8 nM and 20.9 nM. PACAP-38 (10, 100 and 1000 microg/kg i.p. in 200 microl volume) inhibited neurogenic ear swelling in the mouse. Furthermore, 100 microg/kg i.p. PACAP also significantly diminished mustard oil-evoked plasma protein extravasation in the rat skin. These results suggest that PACAP-38 is released from the stimulated peripheral terminals of capsaicin-sensitive afferents and it is able to inhibit the outflow of sensory neuropeptides. Based on this mechanism of action PACAP is also able to effectively diminish/abolish neurogenic inflammatory response in vivo after systemic administration.