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Prokineticins (PKs) are low molecular weight proteins that exert their effects by binding to two seven-transmembrane G-protein-coupled receptors (prokineticin receptors, PKRs). The prokineticin system is an important player in the development of various diseases. Several polymorphisms that are associated with infertility, neuroendocrine disorders, Hirschsprung's syndrome (HSCR), idiopathic central precocious puberty (CPP) and congenital disorders such as Kallmann syndrome (KS) have been described for both the PKs and PKR genes. The aim of this study is to summarize and describe the impact of PK/PKR polymorphisms on the pathogenesis and outcome of the above diseases, highlighting the PK system as a therapeutic target and diagnostic biomarker in pathological conditions. [ABSTRACT FROM AUTHOR]

G protein-coupled receptors (GPCRs) are transmembrane proteins that mediate the intracellular pathway of signals not only through heterotrimeric GTP-binding proteins (G proteins) but also through their associations with a variety of additional partner proteins. Prokineticin receptors 1 (PKR1) and 2 (PKR2) are new members of the GPCRs whose ligands are the novel chemokines prokineticin 1 (PK1) and prokineticin 2 (PK2). The multiplicity of G proteins coupled to PKRs, the ability of PKR2 to heterodimerize, the interaction of PKR2 with accessory proteins, and the existence of alternative splice isoforms of PKR2/PK2 explain the complexity of the system in the signal transduction pathway and, consequently, in the modulation of various physiological and pathological functions. Knowledge of these mechanisms provides the basis for the development of targeted drugs with therapeutic efficacy in PK-dependent diseases.

Definition: G protein-coupled receptors (GPCRs) are transmembrane proteins that mediate the intracellular pathway of signals not only through heterotrimeric GTP-binding proteins (G proteins) but also through their associations with a variety of additional partner proteins. Prokineticin receptors 1 (PKR1) and 2 (PKR2) are new members of the GPCRs whose ligands are the novel chemokines prokineticin 1 (PK1) and prokineticin 2 (PK2). The multiplicity of G proteins coupled to PKRs, the ability of PKR2 to heterodimerize, the interaction of PKR2 with accessory proteins, and the existence of alternative splice isoforms of PKR2/PK2 explain the complexity of the system in the signal transduction pathway and, consequently, in the modulation of various physiological and pathological functions. Knowledge of these mechanisms provides the basis for the development of targeted drugs with therapeutic efficacy in PK-dependent diseases. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is the most prevalent joint disease associated with chronic pain. OA pain is often accompanied by mood disorders. We addressed the role of the Prokineticin (PK) system in pain and mood alterations in a mice OA model induced with monosodium iodoacetate (MIA). The effect of a PK antagonist (PC1) was compared to that of diclofenac. C57BL/6J male mice injected with MIA in the knee joint were characterized by allodynia, motor deficits, and fatigue. Twenty-eight days after MIA, in the knee joint, we measured high mRNA of PK2 and its receptor PKR1, pro-inflammatory cytokines, and MMP13. At the same time, in the sciatic nerve and spinal cord, we found increased levels of PK2, PKR1, IL-1β, and IL-6. These changes were in the presence of high GFAP and CD11b mRNA in the sciatic nerve and GFAP in the spinal cord. OA mice were also characterized by anxiety, depression, and neuroinflammation in the prefrontal cortex and hippocampus. In both stations, we found increased pro-inflammatory cytokines. In addition, PK upregulation and reactive astrogliosis in the hippocampus and microglia reactivity in the prefrontal cortex were detected. PC1 reduced joint inflammation and neuroinflammation in PNS and CNS and counteracted OA pain and emotional disturbances. [ABSTRACT FROM AUTHOR]

Knee osteoarthritis (OA) is a chronic degenerative inflammatory-based condition caused by a cascade of different intra-articular molecules including several cytokines. Among the cytokines, prokineticins (PKs) have recently been identified as important mediators of inflammation and pain. This observational study examined the potential involvement of PK2 in degenerative or traumatic knee disease. Fifteen patients presenting knee osteoarthritis (OA group) and 15 patients presenting a traumatic meniscal tear (TM group) were studied. Synovial fluid samples from affected knees were assessed for PK2, IL-10, and TNF-α using the ELISA method. At a long-term follow-up (minimum 5 years, mean = 6.1 years), patients in the TM group underwent clinical re-evaluation with PROMs (Tegner Activity Scale, IKDC, Lysholm, SKV); in addition, X-ray visualization was used to assess the presence of secondary OA. PK2 was detected in synovial fluids of both TM and OA patients and the levels were comparable between the two groups, while IL-10 levels were significantly greater in the OA group than those in TM patients. PK2 levels correlated with those of IL-10. PK2 levels were greater in blood effusions compared to clear samples, did not differ significantly between sexes, nor were they related to differences in weight, height, or injury (meniscal laterality, time since dosing). No correlation was found between PROMs and radiological classifications in patients in the TM group at final follow-up. These data are the first observations of PK2 in synovial fluid following traumatic meniscus injury. These findings suggest possible further prognostic indices and therapeutic targets to limit the development of secondary OA. [ABSTRACT FROM AUTHOR]

MRAP2 is a small simple transmembrane protein arranged in a double antiparallel topology on the plasma membrane. It is expressed in the paraventricular nucleus of the hypothalamus, where it interacts with various G protein-coupled receptors, such as the prokineticin receptors, and regulates energy expenditure and appetite. The aim of this work was to analyze the functional role of the specific arginine residue at position 125 of MRAP2, which affects protein conformation, dimer formation, and PKR2 binding. Results obtained with the MRAP2 mutants R125H and R125C, which are found in human patients with extreme obesity, and mouse MRAP2, in which arginine 125 is normally replaced by histidine, were compared with those obtained with human MRAP2. Understanding the mechanism by which MRAP2 regulates G protein-coupled receptors helps in elucidating the metabolic pathways involved in metabolic dysfunction and in developing new drugs as specific targets of the MRAP2-PKR2 complex. [ABSTRACT FROM AUTHOR]

Pleasant touch provides emotional and psychological support that helps mitigate social isolation and stress. However, the underlying mechanisms remain poorly understood. Using a pleasant touch- conditioned place preference (PT-CPP) test, we show that genetic ablation of spinal excitatory interneurons expressing prokineticin receptor 2 (PROKR2), or its ligand PROK2 in sensory neurons, abolishes PT-CPP without impairing pain and itch behaviors in mice. Mutant mice display profound impairments in stress response and prosocial behaviors. Moreover, PROKR2 neurons respond most vigorously to gentle stroking and encode reward value. Collectively, we identify PROK2 as a long-sought neuropeptide that encodes and transmits pleasant touch to spinal PROKR2 neurons. These findings may have important implications for elucidating mechanisms by which pleasant touch deprivation contributes to social avoidance behavior and mental disorders. [ABSTRACT FROM AUTHOR]

Melanocortin Receptor Accessory Protein 2 (MRAP2) modulates the trafficking and signal transduction of several G-protein-coupled receptors (GPCRs) involved in the control of energy homeostasis, such as Prokineticin receptors (PKRs). They bind the endogenous ligand prokineticin 2 (PK2), a novel adipokine that has an anorexic effect and modulates thermoregulation and energy homeostasis. In the present work, we used biochemical techniques to analyze the mechanism of interaction of MRAP2 with PKR2 and we identified the specific amino acid regions involved in the complex formation. Our results indicate that MRAP2 likely binds to the N-terminal region of PKR2, preventing glycosylation and consequently the correct receptor localization. We also identified a C-terminal region of MRAP2 that is critical for the interaction with PKR2. Consequently, we analyzed the role of the prokineticin transduction system in the regulation of MRAP2 expression in tissues involved in the control of food intake: at the central level, in hypothalamic explants, and at the peripheral level, in adipocytes. We demonstrated the modulation of MRAP2 expression by the prokineticin transduction system. [ABSTRACT FROM AUTHOR]

Prokineticin 2 (PK2) is a secreted protein involved in several pathological and physiological processes, including the regulation of inflammation, sickness behaviors, and circadian rhythms. Recently, it was reported that PK2 is associated with the pathogenesis of collagen-induced arthritis in mice. However, the role of PK2 in the pathogenesis of rheumatoid arthritis (RA) or osteoarthritis (OA) remains unknown. In this study, we collected synovial tissue, plasma, synovial fluid, and synovial fibroblasts (SF) from RA and OA patients to analyze the function of PK2 using immunohistochemistry, enzyme-linked immunosorbent assays, and tissue superfusion studies. PK2 and its receptors prokineticin receptor (PKR) 1 and 2 were expressed in RA and OA synovial tissues. PKR1 expression was downregulated in RA synovial tissue compared with OA synovial tissue. The PK2 concentration was higher in RA synovial fluid than in OA synovial fluid but similar between RA and OA plasma. PK2 suppressed the production of IL-6 from TNFα-prestimulated OA-SF, and this effect was attenuated in TNFα-prestimulated RA-SF. This phenomenon was accompanied by the upregulation of PKR1 in OA-SF. This study provides a new model to explain some aspects underlying the chronicity of inflammation in RA. [ABSTRACT FROM AUTHOR]

Abstract Background Neuropathy is a dose-limiting side effect of many chemotherapeutics, including bortezomib. The mechanisms underlying this condition are not fully elucidated even if a contribution of neuroinflammation was suggested. Here, we investigated the role of a chemokine family, the prokineticins (PKs), in the development of bortezomib-induced peripheral neuropathy (BIPN), and we used a PK receptor antagonist to counteract the development and progression of the pathology. Methods Neuropathy was induced in male C57BL/6J mice by using a protocol capable to induce a detectable neuropathic phenotype limiting systemic side effects. The presence of allodynia (both mechanical and thermal) and thermal hyperalgesia was monitored over time. Mice were sacrificed at two different time points: 14 and 28 days after the first bortezomib (BTZ) injection. At these times, PK system activation (PK2 and PK-Rs), macrophage and glial activation markers, and cytokine production were evaluated in the main station involved in pain transmission (sciatic nerve, DRG, and spinal cord), and the effect of a PK receptors antagonist (PC1) on the same behavioral and biochemical parameters was assessed. Structural damage of DRG during BTZ treatment and an eventual protective effect of PC1 were also evaluated. Results BTZ induces in mice a dose-related allodynia and hyperalgesia and a progressive structural damage to the DRG. We observed a precocious increase of macrophage activation markers and unbalance of pro- and anti-inflammatory cytokines in sciatic nerve and DRG together with an upregulation of GFAP in the spinal cord. At higher BTZ cumulative dose PK2 and PK receptors are upregulated in the PNS and in the spinal cord. The therapeutic treatment with the PK-R antagonist PC1 counteracts the development of allodynia and hyperalgesia, ameliorates the structural damage in the PNS, decreases the levels of activated macrophage markers, and prevents full neuroimmune activation in the spinal cord. Conclusions PK system may be a strategical pharmacological target to counteract BTZ-induced peripheral neuropathy. Blocking PK2 activity reduces progressive BTZ toxicity in the DRG, reducing neuroinflammation and structural damage to DRG, and it may prevent spinal cord sensitization.

Successful pregnancy establishment in mammals depends on proper embryo-maternal communication. Prokineticin 1 (PROK1) is a secretory protein that exerts pleiotropic functions in various tissues. Despite the studies that have primarily been performed with human cell lines and mice, the function of PROK1 in trophoblasts has still not been fully elucidated. Hence, the aim of this study was to establish the role of PROK1 in trophoblasts during implantation and placentation. Prokineticin 1 mRNA was elevated in porcine trophoblasts during implantation and the early placentation period. Furthermore, we reveal that PROK1–PROKR1 signaling induces the expression of genes involved in the regulation of angiogenesis, immunological response, trophoblast cell adhesion, invasion, and proliferation, as well as stimulating phosphorylation of MAPK and PTK2. Ingenuity Pathway Analysis identified the aforementioned and also other functions associated with PROK1-regulated genes/proteins, such as cell-to-cell contact, epithelial tissue differentiation, Ca2+ release, lipid synthesis, and chemotaxis. We also showed evidence that PROK1 acting via PROKR1 increased trophoblast cell proliferation and adhesion. The PROK1-stimulated cell proliferation was mediated by PI3K/AKT/mTOR, MAPK, and cAMP, whereas adhesion was mediated by MAPK and/or PI3K/AKT signaling pathways. Concluding, our study suggests that PROK1 plays a pleiotropic role in trophoblast function during implantation and early placentation. [ABSTRACT FROM AUTHOR]

Vasculogenesis and angiogenesis are key processes of placental development, which occur throughout pregnancy. Placental vasculogenesis occurs during the first trimester of pregnancy culminating in the formation of hemangioblasts from intra-villous stem cells. Placental angiogenesis occurs subsequently, forming new blood vessels from existing ones. Angiogenesis also takes place at the fetomaternal interface, allowing essential spiral arteriole remodeling to establish the fetomaternal circulation. Vasculogenesis and angiogenesis in animal models and in humans have been studied in a wide variety of in vitro, physiological and pathological conditions, with a focus on the pro- and anti-angiogenic factors that control these processes. Recent studies revealed roles for new families of proteins, including direct participants such as the prokineticin family, and regulators of these processes such as the homeobox genes. This review summarizes recent advances in understanding the molecular mechanisms of actions of these families of proteins. Over the past decade, evidence suggests increased production of placental anti-angiogenic factors, as well as angiogenic factors are associated with fetal growth restriction (FGR) and preeclampsia (PE): the most threatening pathologies of human pregnancy with systemic vascular dysfunction. This review also reports novel clinical strategies targeting members of these family of proteins to treat PE and its consequent effects on the maternal vascular system.

Neurotoxicity is a common side effect of chemotherapeutics that often leads to the development of chemotherapy-induced peripheral neuropathy (CIPN). The peptide Prokineticin 2 (PK2) has a key role in experimental models of CIPN and can be considered an insult-inducible endangering mediator. Since primary afferent sensory neurons are highly sensitive to anticancer drugs, giving rise to dysesthesias, the aim of our study was to evaluate the alterations induced by vincristine (VCR) and bortezomib (BTZ) exposure in sensory neuron cultures and the possible preventive effect of blocking PK2 signaling. Both VCR and BTZ induced a concentration-dependent reduction of total neurite length that was prevented by the PK receptor antagonist PC1. Antagonizing the PK system also reduced the upregulation of PK2, PK-R1, TLR4, IL-6, and IL-10 expression induced by chemotherapeutic drugs. In conclusion, inhibition of PK signaling with PC1 prevented the neurotoxic effects of chemotherapeutics, suggesting a promising strategy for neuroprotective therapies against the sensory neuron damage induced by exposure to these drugs.

The article presents the discussion on research of various topics. Topics include Clerke Reef atoll at the Rowley Shoals in Western Australia providing a model habitat spatially varying selection drives ecological divergence; identifying interneurons in laminae II of the spinal cord dorsal horn expressing prokineticin receptor 2; and piezoelectric materials converting mechanical forces into electrical signals being used as the active material in many pressure sensors.

Vasculogenesis and angiogenesis are key processes of placental development, which occur throughout pregnancy. Placental vasculogenesis occurs during the first trimester of pregnancy culminating in the formation of hemangioblasts from intra-villous stem cells. Placental angiogenesis occurs subsequently, forming new blood vessels from existing ones. Angiogenesis also takes place at the fetomaternal interface, allowing essential spiral arteriole remodeling to establish the fetomaternal circulation. Vasculogenesis and angiogenesis in animal models and in humans have been studied in a wide variety of in vitro , physiological and pathological conditions, with a focus on the pro- and anti-angiogenic factors that control these processes. Recent studies revealed roles for new families of proteins, including direct participants such as the prokineticin family, and regulators of these processes such as the homeobox genes. This review summarizes recent advances in understanding the molecular mechanisms of actions of these families of proteins. Over the past decade, evidence suggests increased production of placental anti-angiogenic factors, as well as angiogenic factors are associated with fetal growth restriction (FGR) and preeclampsia (PE): the most threatening pathologies of human pregnancy with systemic vascular dysfunction. This review also reports novel clinical strategies targeting members of these family of proteins to treat PE and its consequent effects on the maternal vascular system. [ABSTRACT FROM AUTHOR]

Neurotoxicity is a common side effect of chemotherapeutics that often leads to the development of chemotherapy-induced peripheral neuropathy (CIPN). The peptide Prokineticin 2 (PK2) has a key role in experimental models of CIPN and can be considered an insult-inducible endangering mediator. Since primary afferent sensory neurons are highly sensitive to anticancer drugs, giving rise to dysesthesias, the aim of our study was to evaluate the alterations induced by vincristine (VCR) and bortezomib (BTZ) exposure in sensory neuron cultures and the possible preventive effect of blocking PK2 signaling. Both VCR and BTZ induced a concentration-dependent reduction of total neurite length that was prevented by the PK receptor antagonist PC1. Antagonizing the PK system also reduced the upregulation of PK2, PK-R1, TLR4, IL-6, and IL-10 expression induced by chemotherapeutic drugs. In conclusion, inhibition of PK signaling with PC1 prevented the neurotoxic effects of chemotherapeutics, suggesting a promising strategy for neuroprotective therapies against the sensory neuron damage induced by exposure to these drugs. [ABSTRACT FROM AUTHOR]

There has been controversy over the cardiovascular safety of domperidone, attributable to the lack of a well-designed study as well as inconsistent results. This study aimed to examine the risk of severe domperidone-induced ventricular arrhythmia (VA), compared to mosapride, itopride, or non-use of all three prokinetics, in the general population. We conducted a population-based, self-controlled case series analysis. Enrolled subjects were individuals who were diagnosed with severe VA and were prescribed domperidone, mosapride, or itopride from 2003 to 2013 in the National Health Insurance Service-National Sample Cohort. The incidence rate ratio for severe VA was measured during exposure to prokinetics and compared with unexposed periods and itopride (no-proarrhythmic effect)-exposure periods, as control. A total of 2,817 subjects were included. Domperidone, mosapride, or itopride use was associated with increased risk of severe VA, compared with non-use (adjusted incidence rate ratios (IRR) of 1.342 (95% CI 1.096–1.642), 1.350 (95% CI 1.105–1.650), and 1.486 (95% CI 1.196–1.845), respectively). The risk of severe domperidone-induced VA was lower, compared to that of itopride [adjusted IRR of 0.548 (95% CI 0.345–0.870)]. Of the subjects who had been prescribed all three prokinetics, domperidone-exposure was associated with a lower risk of severe VA, compared to itopride-exposure (crude IRR, 0.571; 0.358–0.912). Mosapride-exposure did not show IRR difference for severe VA, compared to itopride-exposure. Domperidone, mosapride, or itopride use is associated with an increased risk of severe VA. However, the magnitude of association was modest and domperidone use does not increase further the risk, compared with other prokinetics. [ABSTRACT FROM AUTHOR]

Prokineticin receptors (PROKR1 and PROKR2) are G protein-coupled receptors which control human central and peripheral reproductive processes. Importantly, allelic variants of PROKR2 in humans are associated with altered migration of GnRH neurons, resulting in congenital hypogonadotropic hypogonadism (CHH), a heterogeneous disease characterized by delayed/absent puberty and/or infertility. Although this association is established in humans, murine models failed to fully recapitulate the reproductive and olfactory phenotypes observed in patients harboring PROKR2 mutations. Here, taking advantage of zebrafish model we investigated the role of prokr1b (ortholog of human PROKR2) during early stages of GnRH neuronal migration. Real-Time PCR and whole mount in situ hybridization assays indicate that prokr1b spatial-temporal expression is consistent with gnrh3. Moreover, knockdown and knockout of prokr1b altered the correct development of GnRH3 fibers, a phenotype that is rescued by injection of prokr1b mRNA. These results suggest that prokr1b regulates the development of the GnRH3 system in zebrafish. Analysis of gonads development and mating experiments indicate that prokr1b is not required for fertility in zebrafish, although its loss determine changes also at the testis level. Altogether, our results support the thesis of a divergent evolution in the control of vertebrate reproduction and provide a useful in vivo model for deciphering the mechanisms underlying the effect of PROKR2 allelic variants on CHH. [ABSTRACT FROM AUTHOR]

Prokineticins are a new class of chemokine-like peptides that bind their G protein-coupled receptors, PKR1 and PKR2, and promote chemotaxis and the production of pro-inflammatory cytokines following tissue injury or infection. This review summarizes the major cellular and biochemical mechanisms of prokineticins pathway regulation that, like other chemokines, include: genetic polymorphisms; mRNA splice modulation; expression regulation at transcriptional and post-transcriptional levels; prokineticins interactions with cell-surface glycosaminoglycans; PKRs degradation, localization, post-translational modifications and oligomerization; alternative signaling responses; binding to pharmacological inhibitors. Understanding these mechanisms, which together exert substantial biochemical control and greatly enhance the complexity of the prokineticin-receptor network, leads to novel opportunities for therapeutic intervention. In this way, besides targeting prokineticins or their receptors directly, it could be possible to indirectly influence their activity by modulating their expression and localization or blocking the downstream signaling pathways.

Prokineticins are a new class of chemokine-like peptides involved in a wide range of biological and pathological activities. In particular, prokineticin 2 (PK2), prokineticin receptor 1 (PKR1) and prokineticin receptor 2 (PKR2) play a central role in modulating neuroinflammatory processes. PK2 and PKRs, which are physiologically expressed at very low levels, are strongly upregulated during inflammation and regulate neuronal-glial interaction. PKR2 is mainly overexpressed in neurons, whereas PKR1 and PK2 are mainly overexpressed in astrocytes. Once PK2 is released in inflamed tissue, it is involved in both innate and adaptive responses: it triggers macrophage recruitment, production of pro-inflammatory cytokines, and reduction of anti-inflammatory cytokines. Moreover, it modulates the function of T cells through the activation of PKR1 and directs them towards a pro-inflammatory Th1 phenotype. Since the prokineticin system appears to be upregulated following a series of pathological insults leading to neuroinflammation, we will focus here on the involvement of PK2 and PKRs in those pathologies that have a strong underlying inflammatory component, such as: inflammatory and neuropathic pain, Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, stroke, obesity, diabetes, and gastrointestinal inflammation.

Alzheimer’s disease is the most common neurodegenerative disorder characterized by the presence of β-amyloid aggregates deposited as senile plaques and by the presence of neurofibrillary tangles of tau protein. To date, there is a broad consensus on the idea that neuroinflammation is one of the most important component in Alzheimer’s disease pathogenesis. Chemokines and their receptors, beside the well-known role in the immune system, are widely expressed in the nervous system, where they play a significant role in the neuroinflammatory processes. Prokineticins are a new family of chemokine-like molecules involved in numerous physiological and pathological processes including immunity, pain, inflammation, and neuroinflammation. Prokineticin 2 (PROK2) and its receptors PKR1 and PKR2 are widely expressed in the central nervous system in both neuronal and glial cells. In Alzheimer’s disease, PROK2 sustains the neuroinflammatory condition and contributes to neurotoxicity, since its expression is strongly upregulated by amyloid-β peptide and reversed by the PKR antagonist PC1. This review aims to summarize the current knowledge on the neurotoxic and/or neuroprotective function of chemokines in Alzheimer’s disease, focusing on the prokineticin system: it represents a new field of investigation that can stimulate the research of innovative pharmacotherapeutic strategies.

• Vincristine treated mice develop neuropathic pain but not mood alterations. • Prokineticins are involved in the progression and worsening of hypersensitivity. • Prokineticin antagonism counteracts pain and neuroinflammation. • PK system is a promising pharmacological target to contrast chemotherapy-induced neuropathy. Vincristine (VCR) treatment is often associated to painful neuropathy. Its development is independent from antitumoral mechanism and involves neuroinflammation. We investigated the role of the chemokine prokineticin (PK)2 in a mouse model of VCR induced neuropathy using a PK-receptors (PK-R) antagonist to counteract its development. We also evaluated emotional like deficits in VCR mice. VCR (0,1 mg/kg) was i.p. injected in C57BL/6J male mice once a day for 14 consecutive days. Pain, anxiety and depressive like behaviors were assessed in animals. PK2, PK-Rs, cytokines, neuroinflammatory markers (CD68, CD11b, GFAP, TLR4) and ATF3 were evaluated in DRG, spinal cord, prefrontal cortex and hippocampus. The PK-Rs antagonist PC1, was s.c. injected (150 μg/kg) twice a day from day 7 (hypersensitivity state) until day 14. Its effect on pain and neuroinflammation was evaluated. VCR mice developed neuropathic pain but not mood alterations. After 7 days of VCR treatment we observed a neuroinflammatory condition in DRG with high levels of PK-Rs, TLR4, CD68, ATF3 and IL-1β without relevant alterations in spinal cord. At day 14, an upregulation of PK system and a marked neuroinflammation was evident also in spinal cord. Moreover, at the same time, we observed initial alterations in supraspinal brain areas. PC1 treatment significantly counteracted neuropathic pain and blunted neuroinflammation. [ABSTRACT FROM AUTHOR]

Infections of the reproductive tract are known to contribute to testicular inflammatory impairment, leading to an increase of pro-inflammatory cytokines such as IL-1β, and a decline in sperm quality. Prokineticin 2 (PK2), a secretory protein, is closely associated with the secretion of pro-inflammatory cytokines in inflamed tissue. It was reported that increased PK2 is related to the upregulation of IL-1β, but the underlying mechanism remains elusive. Here, we illustrated that PK2 was upregulated in testicular macrophages (TM) in a rat model of uropathogenic Escherichia coli (UPEC) infection, which induced the activation of the NLRP3 inflammasome pathway to boost IL-1β secretion. Administration of PK2 inhibitor alleviated the inflammatory damage and suppressed IL-1β secretion. Moreover, PK2 promoted NLRP3 expression and the release of cleaved IL-1β from TM to the supernatants after the challenge with UPEC in vitro. IL-1β in the supernatants affected Leydig cells by suppressing the expression of genes encoding for the enzymes P450scc and P450c17, which are involved in testosterone production. Overall, we revealed that increased PK2 levels in TM in UPEC-induced orchitis may impair testosterone synthesis via the activation of the NLRP3 pathway. Our study provides a new insight into the mechanisms underlying inflammation-associated male infertility and suggests an anti-inflammatory therapeutic target for male infertility. [ABSTRACT FROM AUTHOR]

1. The pharmacokinetics (PKs) analysis of compounds absorbed after the oral administration of Si-Ni-San (SNS) decoction to functional dyspepsia (FD) patients was designed to detect whether the effects were similar to prokinetics administered to healthy rats, without ethical limitation. 2. First, the absorbed compounds, liquiritigenin (L), naringenin (N) and hesperitin (H) in the plasma were identified by UPLC-MS/MS following the oral administration of SNS decoction to subjects with FD. Next, the natural ratio of LNH in the SNS decoction was determined by UPLC. Third, gastric emptying and intestinal transit after the oral administration of LNH, in combination or alone, was compared with those observed after SNS administration in healthy rats. Additionally, the clinical PKs of LNH was studied. 3. The prokinetic efficacy of LNH administered at their natural ratios (7.5:5:1) increased dose-dependently and was better than the observed efficacy when administered alone in rats. Analysis of the clinical PK parameters, calculated using a one-compartment model, showed that the Cmax parameters of LNH in 3, 4 and 4 h were 639.17, 410.00 and 181.67 μg/L, respectively. 4. The clinical herbal PK analysis of the absorbed LNH preclinical prokinetic compounds, in their natural ratio from SNS, highlights the impact of an herbal translational pharmacology study. [ABSTRACT FROM AUTHOR]

Alzheimer's disease is the most common neurodegenerative disorder characterized by the presence of β-amyloid aggregates deposited as senile plaques and by the presence of neurofibrillary tangles of tau protein. To date, there is a broad consensus on the idea that neuroinflammation is one of the most important component in Alzheimer's disease pathogenesis. Chemokines and their receptors, beside the well-known role in the immune system, are widely expressed in the nervous system, where they play a significant role in the neuroinflammatory processes. Prokineticins are a new family of chemokine-like molecules involved in numerous physiological and pathological processes including immunity, pain, inflammation, and neuroinflammation. Prokineticin 2 (PROK2) and its receptors PKR1 and PKR2 are widely expressed in the central nervous system in both neuronal and glial cells. In Alzheimer's disease, PROK2 sustains the neuroinflammatory condition and contributes to neurotoxicity, since its expression is strongly upregulated by amyloid-β peptide and reversed by the PKR antagonist PC1. This review aims to summarize the current knowledge on the neurotoxic and/or neuroprotective function of chemokines in Alzheimer's disease, focusing on the prokineticin system: it represents a new field of investigation that can stimulate the research of innovative pharmacotherapeutic strategies. [ABSTRACT FROM AUTHOR]

Cinitapride (CIN) is a drug for functional dyspepsia. The purpose of the study was to investigate the pharmacokinetics and tolerability of CIN in healthy Chinese volunteers. A randomized, open-label, single- and multiple-dose study was conducted in 12 healthy volunteers. Three different doses of CIN (1, 2, 4 tablets) were given to six groups in the single-dose study, and one tablet (1 mg) of CIN was administered three times a day in the multiple-dose study. Blood samples were collected at predetermined time intervals after CIN dosing and analyzed by LC-MS/MS. Eleven volunteers completed the study. After single dose, the Cmax and AUC of plasma increased approximately linearly with dosage; no statistically significant differences were found in pharmacokinetic parameters between three dose groups. After multiple doses, there was no significant change in Tmax and t1/2 compared with the results from the single dose. After repeated doses, AUC0-t and AUC0-∞ were increased, while CLz/F slightly decreased. And no differences between male and female. The pharmacokinetic parameters of this study were consistent with study results of non-Chinese subjects. Good tolerability was demonstrated in both single- and multiple-dose studies with dosage range from 1 to 4 mg in healthy Chinese subjects. [ABSTRACT FROM AUTHOR]

Abstract Traumatic brain injury is an important cause of global morbidity and mortality. After an initial injury, there is a cascade of cellular and molecular events that ultimately lead to cell death. Therapies aim to both counteract these mechanisms and replenish the lost cell population in order to improve recovery. The adult mammal brain has at least two neurogenic regions that maintain physiological functions: the subgranular zone of the dentate gyrus in the hippocampus, which produces neurons that integrate locally, and the subventricular zone (SVZ) adjacent to the lateral ventricles, which produces neuroblasts that migrate through the rostral migratory stream (RMS) to the olfactory bulbs. Brain injuries, as well as neurodegenerative diseases, induce the SVZ to respond by increasing cell proliferation and migration to the injured areas. Here we report that cells migrate from the SVZ and RMS to the injured cortex after traumatic brain injury in mice, and that the physiological RMS migration is not impaired. We also show that Prokineticin 2 (PROK2), a chemokine important for the olfactory bulb neurogenesis, expressed exclusively by cortical microglia in the cortex as early as 24 h after injury. We then show that administration of a PROK2 receptor antagonist decreases the number of SVZ cells that reach the injured cortex, while injection of recombinant PROK2 into the cortex of uninjured mice attracts SVZ cells. We also demonstrate that cells expressing PROK2 in vitro directionally attract SVZ cells. These data suggest that PROK2 could be utilized in regeneration efforts for the acutely injured mammalian cortex. Graphical abstract After TBI, local microglia express PROK2 near the injury site. SVZ and RMS derived-neural progenitor cells migrate to the injured cortex through the chemmoatractant activity of cortical PROK2. OB, olfactory bulb; RMS, rostral migratory stream; LV, lateral ventricle. Unlabelled Image Highlights • RMS migration is not impaired after TBI. • TBI induces the expression of PROK2 by local microglia. • PROK2 has the potential to stimulate the migration of neural progenitor cells from the SVZ to the injured cortex. [ABSTRACT FROM AUTHOR]

Abstract Prokineticins are involved in many physiological processes including circadian rhythms, neurogenesis, angiogenesis, and cancer. Recently, they have been found to play a role in regulating food intake. Historically, proteins that increase feeding behavior in mammals decrease reproductive behavior to prevent pregnancy and lactation when food is scarce. In the current study, prokineticin-2 (PK2) had pronounced effects on reproductive and ingestive behaviors when given to female Syrian hamsters. Administration of PK2 prevented ingestive behaviors induced by food restriction, such as the amount of time spent with food and eating. Hamsters given PK2 preferred to engage in reproductive behaviors, including spending time with a male and lordosis. Furthermore, analysis of blood plasma revealed that changes to behavior persisted despite similar levels of des-acyl ghrelin (DAG) and reduced glucose concentrations in the blood. Additionally, administering 10 mg/kg of acyl ghrelin (AG) to a different cohort of animals significantly decreased the amount of time females spent with a potential mating partner, increased the amount of time females spent with food, decreased the duration of lordosis, and increased the duration of eating. Results from the current study support the need for further research investigating the reproductive and ingestive roles of PK2 and ghrelin. Highlights • Prokineticin-2 increases reproductive behavior and decreases ingestive behavior in female Syrian hamsters • Prokineticin-2 enhances reproductive behavior despite decreased blood glucose and a slight increase in des-acyl ghrelin • 10 mg/kg of ghrelin decreases reproductive behavior and increases ingestive behavior in female Syrian hamsters [ABSTRACT FROM AUTHOR]

Background: The Augmented Versus Routine Approach to Giving Energy Trial (TARGET) is the largest blinded enteral nutrition (EN) intervention trial evaluating energy delivery to be conducted in the critically ill. To determine the external validity of TARGET results, nutrition practices in intensive care units (ICUs) in Australia and New Zealand (ANZ) are described and compared with international practices.Methods: This was a retrospective analysis of prospectively collected data for the International Nutrition Surveys, 2007-2013. Data are presented as mean (SD).Results: A total of 17,154 patients (ANZ: n = 2776 vs international n = 14,378) from 923 ICUs (146 and 777, respectively) were included. EN was the most common route of feeding (ANZ: 85%, n = 2365 patients vs international: 84%, n = 12,034; P = .258), and EN concentration was also similar (<1.25 kcal/mL ANZ: 70%, n = 12,396 vs international: 65%, n = 56,891 administrations; P < .001). Protein delivery was substantially below the estimated prescriptions but similar between the regions (0.6 [0.4] g/kg/day vs 0.6 [0.4] g/kg/day; P = .849). Patients in ANZ received slightly more energy (1133 [572] vs 948[536] kcal/day; P < .001), possibly because more energy was prescribed (1947 [348] vs 1747 [376] kcal/day; P < .001), nutrition protocols were more commonly used (98% vs 75%; P < .001) and included recommendations for therapies such as prokinetic agents (87% vs 51%, n = 399; P < .001) and small bowel feeding (62% vs 40%; P < .001) when compared with international ICUs.Conclusions: Key elements of nutrition practice are similar in ANZ and international ICUs. These data can be used to determine the external validity and relevance of TARGET results. [ABSTRACT FROM AUTHOR]

Itopride hydrochloride (ITO HCl) is a prokinetic agent, used in the treatment of gastrointestinal motility disorders. The aim of the study was to develop stable mucoadhesive thermoreversible nasal gel to avoid first pass effect. ITO HCl was incorporated into the blends of thermoreversible polymers like poloxamer 407 and various mucoadhesive polymers in different concentrations to increase the contact of the formulations with nasal mucosa. The compatibility between the drug and the suggested polymers was studied by Fourier transform infrared and differential scanning calorimetry (DSC). The formulations were evaluated for clarity, pH, gelation temperature, mucoadhesive strength, gel strength, viscosity, and drug content. In addition, the in vitro drug release and the dissolution efficiency (DE)% were measured. The optimized formulations that showed the highest dissolution efficiency% (DE%) in saline phosphate buffer of pH 6.4 at 35 ± 0.5 °C were chosen for stability testing at temperatures of 4 ± 2 and 25 ± 2 °C/60 ± 5% RH. It was found that F1 and F17 that contain 18% w/v poloxamer 407 and 0.5% w/v of hydroxypropylmethyl cellulose K4M or methyl cellulose (MC), respectively, showed higher stability results as indicated by their higher t90 values (days). [ABSTRACT FROM AUTHOR]

Introduction: To compare the predictive effectiveness levels of prokineticin-1 (PROK1), pregnancy-associated plasma protein A (PAPP-A) and the PROK1/PAPP-A ratio in the first trimester for preeclampsia (PE), foetal growth restriction (FGR), gestational diabetes mellitus (GDM) and spontaneous preterm birth (SPB).Materials and Methods: A total of randomly selected 162 pregnant women were included. Peripheral blood samples were obtained between 110/7 and 136/7 gestational weeks (GWs). All women were followed throughout the pregnancy and classified into five groups as having PE, FGR, GDM, SPB and uncomplicated pregnancies. The cut-off levels of the markers were identified to predict adverse outcomes.Results: PROK1 predicted PE with 83.3% sensitivity, 85.7% specificity at a value of >293.4 pg/mL; at a value of >260.2 pg/mL, PROK1 predicted FGR with 85.7% sensitivity, 72.5% specificity in the first trimester. The area under receiver operating characteristic (ROC) curve of PAPP-A was lower than that of PROK1 and PROK1/PAPP-A in differentiating PE and FGR from the uncomplicated group (p < .001). PROK1 levels and the PROK1/PAPP-A ratios in the SPB and GDM groups were lower than in the uncomplicated group (p < .01).Conclusions: Elevated PROK1 in the first trimester is a more effective marker than PAPP-A in the prediction of PE and FGR. Lower PROK1 levels are associated with the development of SPB and GDM. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of the three different prokinetic agents, namely erythromycin, lidocaine, and metoclopramide in lambs with postoperative ileus (POI) using motilin and ghrelin, which are known as motility markers. Twenty lambs were allocated to 4 groups of 5 lambs each. An enterotomy was performed on the ileum of each lamb. Erythromycin (8.8 mg/kg), metoclopramide (0.2 mg/kg), and saline (2 mL) were administered as single dose IM before surgery in the ERT, MET, and CNTR groups, respectively. Lidocaine was administered to the LID group, both as a bolus before (1.3 mg/kg IV) and as a continuous rate infusion during surgery (0.05 mg/kg/h IV). Serum motilin and ghrelin concentrations as motility hormones were measured with ELISA. The serum motilin concentration was significantly higher at 0, 1, 3, 5, 10, 24, and 48 h in the ERT group and at 1 and 10 h in the LID group. The serum ghrelin concentration was significantly higher at 0, 1, and 48 h in the ERT group and at 3, 5, 10, 24, and 48 h in the LID group. As a result, erythromycin and lidocaine was thought to be useful in lambs with POI according to the stimulatory effects on the motility hormones. [ABSTRACT FROM AUTHOR]

Background: Angiogenesis is integral for embryogenesis, and targeting angiogenesis improves the outcome of many pathological conditions in patients. TBX20 is a crucial transcription factor for embryonic development, and its deficiency is associated with congenital heart disease. However, the role of TBX20 in angiogenesis has not been described.Methods: Loss- and gain-of-function approaches were used to explore the role of TBX20 in angiogenesis both in vitro and in vivo. Angiogenesis gene array was used to identify key downstream targets of TBX20.Results: Unbiased gene array survey showed that TBX20 knockdown profoundly reduced angiogenesis-associated PROK2 (prokineticin 2) gene expression. Indeed, loss of TBX20 hindered endothelial cell migration and in vitro angiogenesis. In a murine angiogenesis model using subcutaneously implanted Matrigel plugs, we observed that TBX20 deficiency markedly reduced PROK2 expression and restricted intraplug angiogenesis. Furthermore, recombinant PROK2 administration enhanced angiogenesis and blood flow recovery in murine hind-limb ischemia. In zebrafish, transient knockdown of tbx20 by morpholino antisense oligos or genetic disruption of tbx20 by CRISPR/Cas9 impaired angiogenesis. Furthermore, loss of prok2 or its cognate receptor prokr1a also limited angiogenesis. In contrast, overexpression of prok2 or prokr1a rescued the impaired angiogenesis in tbx20-deficient animals.Conclusions: Our study identifies TBX20 as a novel transcription factor regulating angiogenesis through the PROK2-PROKR1 (prokineticin receptor 1) pathway in both development and disease and reveals a novel mode of angiogenic regulation whereby the TBX20-PROK2-PROKR1 signaling cascade may act as a "biological capacitor" to relay and sustain the proangiogenic effect of vascular endothelial growth factor. This pathway may be a therapeutic target in the treatment of diseases with dysregulated angiogenesis. [ABSTRACT FROM AUTHOR]

Problem: Prokineticin 2 (PK2), a pro‐inflammatory peptide, is highly expressed in primary spermatocytes. However, systematic research on PK2 and testicular inflammation is lacking to date. Method of study: An experimental autoimmune orchitis (EAO) model was established to detect the expression of PK2 and its receptor (prokineticin receptor 1, PKR1) 50 and 80 days after immunization. PK2 siRNA sequence was injected into the rat rete testis to downregulate the expression of PK2. PK2 was over‐expressed in the testis by injecting PK2 protein through the rat rete testis at different concentrations. Testicular morphology and expression of inducible nitric oxide synthase (iNOS) were detected after the intervention. Results: Results showed that PK2 and PKR1 were upregulated in EAO at 50 days and downregulated at 80 days. PK2 over‐expression contributed to the apoptosis of spermatogenic epithelial cells and increased infiltration of the inflammatory cells, whereas PK2 under‐expression showed no change. Furthermore, iNOS expression was increased significantly when PK2 was over‐expressed. Conclusion: This finding demonstrated that the PK2/PKR1 signals may have an essential role in the regulation of testicular inflammation through iNOS. PK2 interference may represent a novel and promising therapeutic strategy for the clinical management of orchitis. [ABSTRACT FROM AUTHOR]

Abstract: Background: Gastrointestinal sensorimotor dysfunction underlies a wide range of esophageal, gastric, and intestinal motility and functional disorders that collectively constitute nearly half of all referrals to gastroenterologists. As a result, substantial effort has been dedicated toward the development of prokinetic agents intended to augment or restore normal gastrointestinal motility. However, the use of several clinically efficacious gastroprokinetic agents, such as cisapride, domperidone, erythromycin, and tegaserod, is associated with unfavorable cardiovascular safety profiles, leading to restrictions in their use. Purpose: The purpose of this review is to detail the cellular and molecular mechanisms that lead commonly to drug‐induced cardiac arrhythmias, specifically drug‐induced long QT syndrome, torsades de pointes, and ventricular fibrillation, to examine the cardiovascular safety profiles of several classes of prokinetic agents currently in clinical use, and to explore potential strategies by which the risk of drug‐induced cardiac arrhythmia associated with prokinetic agents and other QT interval prolonging medications can be mitigated successfully. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To evaluate the incidence of hypochloremic metabolic alkalosis (HCMA) in dogs and cats in the ICU that had intermittent nasogastric tube (NGT) aspiration for up to 36 hours. Design: Prospective cohort study (December 2013 to October 2014). Setting: Privately owned emergency and referral teaching hospital. Animals: Forty‐nine client‐owned dogs and 16 client‐owned cats. Interventions: Patients wherein NGT placement was recommended and client consent was obtained were included in the interventional group. Those with an NGT placed (NGT group) had the NGT aspirated every 4 hours. Patients for whom placement of a NGT was declined by the owner served as a reference group (NoNGT). Venous blood gas and electrolyte values were obtained every 12 hours. Measurements and Main Results: Thirty‐five dogs and cats had an NGT placed. Thirty dogs and cats did not have an NGT placed. The serum venous blood gas and electrolyte changes were compared over time within the NGT group and between the NGT and NoNGT groups. No cases developed HCMA. In the NGT group, blood pH increased over time. There was no significant difference between the NGT and the NoNGT group in the average value of pH, HCO3−, base excess, chloride, or corrected chloride. Serum venous blood gas, chloride, and corrected chloride changes were not associated with the volumes of gastric fluid aspirated over time. Conclusions: In this small population of dogs and cats, intermittent NGT aspiration was not associated with the development of HCMA over a period of up to 36 hours after NGT placement. [ABSTRACT FROM AUTHOR]

Continued ingestion of plant secondary metabolites by ruminants can provoke pharmacological interactions with pharmaceutical agents used in animals. As some drugs and phytocompounds affect smooth muscle activity, the aim of this study was to verify the possible interaction between selected pharmaceutical agents and plant secondary metabolites towards bovine gastrointestinal motility. The interactions between phytocompounds—apigenin, quercetin, hederagenin, medicagenic acid—and medicines—erythromycin, flunixin meglumine and levamisole—were evaluated on bovine isolated abomasal and duodenal specimens obtained from routinely slaughtered cows. The obtained results confirmed the contractile effect of all three drugs used solely. Hederagenin and medicagenic acid (0.001 μM) enhanced the contractile effect of levamisole. Hederagenin additionally increased the impact of erythromycin. Both saponins (100 μM) showed synergistic effects with all tested pharmaceuticals. Apigenin and quercetin (0.001 μM) intensified the contractile response induced by erythromycin and levamisole. Moreover, both flavonoids (100 μM) showed an antagonistic interaction with all tested drugs which in that situation were devoid of the prokinetic effect. To conclude, plant metabolic metabolites such as saponins and flavonoids are potent modifiers of the effect of drugs towards gut motility. The synergy observed between phytocompounds and selected medicines can be beneficial in the treatment of cows with hypomotility disorders. [ABSTRACT FROM AUTHOR]

Objectives: The onset of parkinsonism in patients with drug-induced parkinsonism (DIP) exhibits extensive individual variability following exposure to offending drugs. We investigated whether the individual variations in the onset time of parkinsonism reflected the underlying subtle dopaminergic dysfunction in DIP.Methods: We enrolled 71 patients with DIP who had visually normal striatal dopamine transporter (DAT) availability in 18F-FP-CIT positron emission tomography scans. According to their exposure durations to the offending drugs prior to onset of the parkinsonism, the patients were divided into the early-onset group (duration ≤6 months; n=35) and delayed-onset group (duration >6 months; n=36). We performed the quantitative analysis of the DAT availability in each striatal subregion between the groups.Results: No patients with DIP had DAT availability that was more than 2 SD below the normal mean of DAT availability. Compared with the delayed-onset group, the early-onset DIP group had decreased DAT availability in the striatal subregions including the posterior putamen (p=0.018), anterior putamen (p=0.011), caudate (p=0.035) and ventral striatum (p=0.027). After adjusting for age, sex and cross-cultural smell identification test scores, a multivariate analysis revealed that the DAT availability in the striatal subregions of the patients with DIP was significantly and positively associated with the natural logarithm of the duration of drug exposure.Conclusions: These results suggest that a short exposure to the offending drugs before the development of parkinsonism would be associated with subtle nigrostriatal dopaminergic dysfunction in patients with DIP. [ABSTRACT FROM AUTHOR]

The suitability of various neurokinin-2 (NK2) receptor agonists and routes of administration to elicit on-demand voiding of the bladder and bowel, as future therapy for individuals with spinal cord injury, was examined using a rat model. The current study examined the feasibility of alternative routes of administration, which are more practical for clinical use than intravenous (IV) administration. Voiding and isovolumetric cystometry were recorded in anesthetized, acutely spinalized, female rats after IV, subcutaneous (SC), intramuscular (IM), intranasal (IN), or sublingual (SL) administration of [Lys 5 ,MeLeu 9 ,Nle 10 ]-NKA (4−10) (LMN-NKA). Administration of LMN-NKA (1–10 μg/kg IV; 10−300 μg/kg SC or IM; 15–1000 μg/kg IN or 300–1500 μg/kg SL) elicited rapid-onset, short-duration, dose-related increases in bladder pressure and voiding with the rank order for time of both onset and duration being IV < IN < SC = IM < SL. The incidence of voiding was dependent on the dose and route, with all routes resulting in a high voiding efficiency (~ 70%). Like LMN-NKA, neurokinin A (NKA 1–100 μg/kg IV) and GR 64349 (0.1–30 μg/kg IV or 1–300 μg/kg SC) produced rapid-onset, short-duration increases in bladder pressure, as well as colorectal pressure. Administration of vehicle never produced bladder or rectal contractions or voiding. Transient hypotension was observed after IV injection of LMN-NKA, which was less pronounced after SC injection. Hypotension was not apparent with GR 64349. In conclusion, selective NK2 receptor agonists, administered through various non-IV routes of administration, may provide a safe, convenient, and efficacious method for inducing voiding. [ABSTRACT FROM AUTHOR]

Background/aim: This study aimed to investigate the potential regulatory role of prokineticin 2 (PK2) in modulation of the number and function of Kupffer cells (KCs) during the progression of liver fibrosis in patients with hepatitis B virus (HBV). Materials and methods: We obtained liver tissue sections from 200 patients with HBV undergoing surgical resection in our hospital between January 2013 and July 2016. Of these 200 tissue sections, 150 were fibrosis tissues and 50 were hepatocellular carcinoma tissues. Immunohistochemical evaluations were performed to assess the expression levels of CD68 and PK2 in the sections. The clinical parameters of these 200 patients were also analyzed. Results: As a potential cytokine, PK2 was commonly expressed in KCs. In addition, a close correlation between PK2 and the number of KCs during the progression of liver fibrosis in patients with HBV was found in this study. Conclusion: PK2 is expressed in KCs and participates in the progression of liver fibrosis after HBV infection. As a potential cytokine, PK2 modulates the number of KCs during fibrosis. Thus, PK2 most likely adjusts the number of M1 cells to modulate the role of KCs in the progression of liver fibrosis after HBV infection. [ABSTRACT FROM AUTHOR]

Prokineticin 1 (PROK1), a hypoxia-regulated angiogenic factor, has emerged as a crucial regulator of embryo implantation and placentation. Dysregulation of PROK1 has been linked to recurrent pregnancy loss, pre-eclampsia, foetal growth restriction and preterm birth. These pregnancy complications are common in women with obesity and polycystic ovary syndrome, i.e. conditions associated with insulin resistance and compensatory hyperinsulinaemia. We investigated the effect of insulin on PROK1 expression during in vitro decidualization. Endometrial stromal cells were isolated from six healthy, regularly menstruating women and decidualized in vitro. Insulin induced a significant dose-dependent up-regulation of PROK1 on both mRNA and protein level in decidualizing endometrial stromal cells. This up-regulation was mediated by hypoxia-inducible factor 1-alpha (HIF1α) via the phosphatidylinositol 3-kinase (PI3K) pathway. Furthermore, we demonstrated that PROK1 did not affect the viability, but significantly inhibited the migration of endometrial stromal cells and the migratory and invasive capacity of trophoblast cell lines. This in vitro study provides new insights into the regulation of PROK1 by insulin in human decidualizing endometrial stromal cells, the action of PROK1 on migration of endometrial stromal cells, as well as migration and invasion of trophoblasts. We speculate that hyperinsulinaemia may be involved in the mechanisms by which PROK1 is linked to placenta-related pregnancy complications. [ABSTRACT FROM AUTHOR]

The Melanocortin Receptor Accessory Protein 2 (MRAP2) regulates the activity of several GPCRs involved in the control of food intake and energy expenditure. While MRAP2 was originally thought to exclusively interact with melanocortin receptors we have recently shown that it interacts with and inhibits the trafficking and signaling of the prokineticin receptor 1 (PKR1). In this study we demonstrate a new role of MRAP2 in the regulation of the orexin receptor 1 (OX1R) and identify the specific regions of MRAP2 required for the regulation of OX1R and PKR1. Importantly, like MC4R and PKRs, OX1R is predominately expressed in the brain where it regulates food intake. By demonstrating that MRAP2 modulates the activity of OX1R we further establish the critical role of MRAP2 in the control of energy homeostasis. [ABSTRACT FROM AUTHOR]

Prokineticin receptor 2 (PROKR2) is predominantly expressed in the mammalian central nervous system. Loss-of-function mutations of PROKR2 in humans are associated with Kallmann syndrome due to the disruption of gonadotropin releasing hormone neuronal migration and deficient olfactory bulb morphogenesis. PROKR2 has been also implicated in the neuroendocrine control of GnRH neurons post-migration and other physiological systems. However, the brain circuitry and mechanisms associated with these actions have been difficult to investigate mainly due to the widespread distribution of Prokr2-expressing cells, and the lack of animal models and molecular tools. Here, we describe the generation, validation and characterization of a new mouse model that expresses Cre recombinase driven by the Prokr2 promoter, using CRISPR-Cas9 technology. Cre expression was visualized using reporter genes, tdTomato and GFP, in males and females. Expression of Cre-induced reporter genes was found in brain sites previously described to express Prokr2, e.g., the paraventricular and the suprachiasmatic nuclei, and the area postrema. The Prokr2-Cre mouse model was further validated by colocalization of Cre-induced GFP and Prokr2 mRNA. No disruption of Prokr2 expression, GnRH neuronal migration or fertility was observed. Comparative analysis of Prokr2-Cre expression in male and female brains revealed a sexually dimorphic distribution confirmed by in situ hybridization. In females, higher Cre activity was found in the medial preoptic area, ventromedial nucleus of the hypothalamus, arcuate nucleus, medial amygdala and lateral parabrachial nucleus. In males, Cre was higher in the amygdalo-hippocampal area. The sexually dimorphic pattern of Prokr2 expression indicates differential roles in reproductive function and, potentially, in other physiological systems. [ABSTRACT FROM AUTHOR]

Background and Aim DA-9701, a newly developed prokinetic agent formulated with Pharbitis Semen and Corydalis Tuber, has been shown to effectively treat functional dyspepsia. Recently, it has also been suspected to improve gastrointestinal motor function. The aims of this study were to assess the effect of DA-9701 on colonic transit time (CTT) and symptoms of functional constipation. Methods Thirty-three patients with functional constipation based on the Rome III criteria were prospectively enrolled. The patients received 30-mg DA-9701 three times a day for 24 days. CTT was estimated initially and at the end of treatment. Symptoms such as spontaneous bowel movements, straining, stool form, feeling of incomplete emptying and anorectal blockage, abdominal discomfort and pain, overall defecation satisfaction, and incidence of adverse events were also analyzed. Results Twenty-seven patients completed the study. DA-9701 was associated with a significantly reduced CTT from 34.9 ± 17.6 to 23.7 ± 19.1 h ( P = 0.001). Segmental CTT also significantly decreased after treatment (right CTT: from 16.8 [0.0-28.8] to 6.0 [0.0-25.2] hours, P < 0.001; rectosigmoid transit time: from 13.2 [0.0-38.4] to 6.0 [0.0-33.6] hours, P = 0.021). In addition, all constipation-related subjective symptoms, including spontaneous bowel movement frequency, significantly improved compared with those before treatment. Serious adverse events did not occur. Conclusions DA-9701 accelerates colonic transit and safely improves symptoms in patients with functional constipation. Therefore, we suggest that this novel agent could help to treat patients with this condition. [ABSTRACT FROM AUTHOR]

The human genome encodes ~750 G-protein-coupled receptors ( GPCRs), including prokineticin receptor 2 ( PROKR2) involved in the regulation of sexual maturation. Previously reported pathogenic gain-of-function mutations of GPCR genes invariably encoded aberrant receptors with excessive signal transduction activity. Although in vitro assays demonstrated that an artificially created inactive mutant of PROKR2 exerted paradoxical gain-of-function effects when co-transfected with wild-type proteins, such a phenomenon has not been observed in vivo. Here, we report a heterozygous frameshift mutation of PROKR2 identified in a 3.5-year-old girl with central precocious puberty. The mutant mRNA escaped nonsense-mediated decay and generated a GPCR lacking two transmembrane domains and the carboxyl-terminal tail. The mutant protein had no in vitro signal transduction activity; however, cells co-expressing the mutant and wild-type PROKR2 exhibited markedly exaggerated ligand-induced Ca2+ responses. The results indicate that certain inactive PROKR2 mutants can cause early puberty by enhancing the functional property of coexisting wild-type proteins. Considering the structural similarity among GPCRs, this paradoxical gain-of-function mechanism may underlie various human disorders. [ABSTRACT FROM AUTHOR]

Background/Aims: Acotiamide, a prokinetic drug, is used to treat functional dyspepsia (FD), especially postprandial distress syndrome (PDS). However, a treatment for FD patients with PDS and/or epigastric pain syndrome (EPS) has not been established. We investigated the efficacy of famotidine in combination with acotiamide for FD. Methods: Fifty blindly randomized FD patients received placebo with acotiamide, or famotidine with acotiamide, for 4 weeks. Treatment efficacy was assessed by overall treatment effects (OTE), total, PDS and EPS symptom scores, and impairment of quality of life (QOL). Results: After OTE assessment, patients who felt affected by treatment comprised 40.9 and 57.9% of famotidine and placebo groups, respectively, after 4 weeks' treatment, with no significant difference between groups. A significant decrease was seen in total, PDS, and EPS symptom scores, and in QOL impairment, after 4 weeks' treatment compared with pretreatment scores for famotidine and placebo groups, but was not observed between groups. The proportion of patients showing a ≥ 50% decrease in EPS symptom scores was greater in the famotidine than that in the placebo group for every observation point, with the greatest difference observed after 2 weeks' treatment. Conclusion: The effectiveness of famotidine and acotiamide combination therapy in FD was similar to the effectiveness of acotiamide therapy alone. [ABSTRACT FROM AUTHOR]

Background Serotonin plays a pivotal role in regulating gut motility, visceral sensitivity, and fluid secretion via specific receptors. Among these receptors, 5- HT4 exerts a prominent control on gut motor function. Although the prokinetic effect exerted by 5- HT4 agonists is well known, the cellular sites of 5- HT4 expression remain poorly understood in large mammals, e.g., horses. In this study, we evaluated the distribution of 5- HT4 in the horse intestine and in foals with enteric aganglionosis, reminiscent of human Hirschsprung's disease. Methods The intestine and spinal ganglia were obtained from three healthy horses and two foals with hereditary ileocolonic aganglionosis. Tissues were processed for immunohistochemistry using a specific antibody to 5- HT4 and a variety of neuronal markers. Myenteric and submucosal plexus 5- HT4-immunoreactive ( IR) neurons were quantified as relative percentage (mean± SD) to the total number of neurons counted. Furthermore, the density of 5- HT4- IR nerve fibers was evaluated in the mucosa and tunica muscularis. Key Results The 5- HT4 immunoreactivity was localized to large percentages of myenteric neurons ranging from 28±9% (descending colon) to 63±19% (ileum), and submucosal neurons ranging from 54±6% (ileum) to 68±14% (duodenum). The 5- HT4-immunoreactivity was co-expressed by some substance P- IR ( SP- IR) spinal ganglion neurons and extrinsic sensory fibers of aganglionic foals. Conclusions & Inferences The presence of 5- HT4 in many enteric and extrinsic sensory neurons and nerve fibers provides solid morphological evidence of the cellular sites of 5- HT4 expression in horses. The evidence of SP- IR sensory neurons positive for 5- HT4 suggests its role in visceral sensitivity. [ABSTRACT FROM AUTHOR]