Two chicken neuromedin U receptors: characterization of primary structure, biological activity and tissue distribution

Neuro-protective effects of n-butylphthalide on carbon monoxide poisoning rats by modulating IL-2, AKT and BCL-2

Acute carbon monoxide poisoning (CO-poisoning) causes neurotoxicity by inducing necrosis, apoptosis, lipid peroxidation, and oxidative stress. DL-3-n-butylphthalide (NBP) is a synthetic compound originally extracted from the seeds of Chinese celery and based on pure l-3-n-butylphthalide. In ischemia/reperfusion, it exerts neuroprotective effects through its anti-apoptotic, anti-necrotic and antioxidant properties, and activation of pro-survival pathways. Our study performed bioinformatic analysis to identify the differential expression genes. CO-poisoning patients' blood was collected to confirm the findings. Male rats were exposed to CO 3000 ppm for 40 min, and NBP (100 mg/kg/day) was continuously injected intraperitoneally immediately after poisoning and for the next 15 days. After NBP treatment, the rats were evaluated by Morris water maze test. At the end of experiments, blood and brain tissues of the rats were collected to evaluate the expression levels of IL-2, AKT and BCL-2. We found that IL-2 was elevated in CO-poisoning patients and animal models. Brain tissue damage in CO-poisoning rats was significantly alleviated after NBP treatment. Furthermore, NBP increased the expression of IL-2, AKT and BCL-2 in rat CO-poisoning model. NBP showed neuroprotective action by increasing IL-2, AKT, and BCL-2 expressions.

Neuromedin U: potential roles in immunity and inflammation

Since the discovery of neuromedin U (NmU) from porcine spinal cord in 1985, this neuropeptide has been subsequently identified in many other species with multiple physiological and pathophysiological roles detected, ranging from smooth muscle contraction, feeding, energy balance to tumorigenesis. Intriguingly, NmU is also emerging to play pro-inflammatory roles involving immune cell activation and cytokine release in a neuron-dependent or neuron-independent manner. The NmU-mediated inflammatory responses have already been observed in worm infection, sepsis, autoimmune arthritis and allergic animal models. In this review, we focus on the roles of NmU in immunity and inflammation by highlighting the interactions between NmU and immune cells, summarizing the signalling mechanism involved in their reactions and discussing its potential contributions to inflammatory diseases.

Characterization of neuromedin U (NMU), neuromedin S (NMS) and their receptors (NMUR1, NMUR2) in chickens

Neuromedin U (NMU) and its structurally-related peptide, neuromedin S (NMS), are reported to regulate many physiological processes and their actions are mediated by two NMU receptors (NMUR1, NMUR2) in mammals. However, the information regarding NMU, NMS, and their receptors is limited in birds. In this study, we examined the structure, functionality, and expression of NMS, NMU, NMUR1 and NMUR2 in chickens. The results showed that: 1) chicken (c-) NMU cDNA encodes a 181-amino acid precursor, which may generate two forms of NMU peptide with 9 (cNMU-9) and 25 amino acids (cNMU-25), respectively. 2) Interestingly, two cNMS transcripts encoding two cNMS precursors of different lengths were identified from chicken pituitary, and both cNMS precursors may produce a mature cNMS peptide of 9 amino acids (cNMS-9). 3) cNMU-9, cNMU-25 and cNMS-9 could activate cNMUR1 expressed in HEK293 cells potently, as monitored by three cell-based luciferase reporter systems, indicating that cNMUR1 can act as a receptor common for cNMU and cNMS peptides, whereas cNMUR2 could be potently activated by cNMS-9, but not by cNMU-9/cNMU-25. 4) cNMU and cNMUR1 are widely expressed in chicken tissues with abundant expression noted in the gastrointestinal tract, as detected by quantitative real-time PCR, whereas cNMUR2 expression is mainly restricted to the brain and anterior pituitary, and cNMS is widely expressed in chicken tissues. Collectively, our data helps to elucidate the physiological roles of NMU/NMS peptides in birds and reveal the functional conservation and changes of NMU/NMS-NMUR axis across vertebrates.