Urotensin II Research Articles

Upregulation of the Urotensin II System in Diabetic Kidney Disease Includes Urotensin II-Related Peptide

The urotensin II (UII) system consists of endogenous ligands UII and its paralog urotensin II-related peptide (URP) and their receptor, UT. Originally isolated from the rat brain, URP is conserved across all vertebrates and shares the same cyclic hexapeptide core sequence with UII. However, UII and URP exhibit different N-terminal amino acid sequences. Beyond the central nervous system, UII and URP are functionally expressed in peripheral tissues. Alterations in tissue expression levels of UII and UT and blood or urinary UII concentrations have been associated with cardiovascular, pulmonary, and kidney dysfunctions, including hypertension, chronic heart failure, pulmonary hypertension, glomerulonephritis, and diabetes, making the UII system a potential therapeutic target for cardiovascular and kidney disease. The skeletal muscle and plasma levels of UII are increased in diabetic mice. Increased kidney tissue expression levels of UII and UT have also been demonstrated in humans and animals with diabetic kidney disease (DKD). Our recent work showed that UT is functionally expressed in cultured mouse glomerular mesangial cells (GMCs). Activation of UT by UII contributes to Ca2+-dependent GMC proliferation and extracellular matrix protein accumulation under high glucose conditions. We have also shown that DKD is attenuated in UT knockout mice. Despite the structural homology between UII and URP, studies have shown that the peptides may exhibit differential central and peripheral expression and pathophysiological function. However, whether URP is dysregulated in DKD remains unclear. Here, we examined whether URP production and kidney expression levels are altered in a hyperglycemic milieu and associated with DKD. Using a streptozotocin (STZ)-induced diabetes model, we examined the kidney tissue, plasma, and urinary levels of UII peptides. We also tested the hypothesis that, like UII, URP stimulates GMC proliferation and matrix protein synthesis. Our data show that protein and mRNA expression levels of both UII and URP were increased in the kidneys of hyperglycemic mice that developed albuminuria. Urinary and plasma UII and URP concentrations were also elevated in the mice. Although both UII and URP stimulated proliferation and type IV collagen production in cultured mouse GMCs by activating UT, the effect of UII was greater. Our data suggests that changes in the UII system in DKD are not limited to UII and UT but include the less-studied URP. GMC proliferation and extracellular matrix accumulation driven by UII and URP may contribute to DKD. NHLBI: R01 HL151735. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Urotensin II system contributes to ischemic acute kidney injury in neonatal pigs

Urotensin II (UII) and UII-related peptide (URP) and their receptor, UT, comprise the UII system. Although UII is conserved across all vertebrates and shares a cyclic hexapeptide core-sequence motif of CFWKYC, there are differences in N-terminal amino acid sequences between species. The kidney is a significant source of UII, the level of which is amplified in infants with chronic kidney disease. We have previously shown that human UII increases renal vascular resistance (RVR) and reduces renal blood flow in neonatal pigs. However, the effect of pig UII (pUII) on renal microcirculation remains unclear. Since the mechanisms of renal ischemia-reperfusion (IR) injury include kidney hypoperfusion, increased activity of the UII system may contribute to ischemic acute kidney injury (AKI). Here, we demonstrate that kidney tissue UII, URP, and UT and renal vascular UT expression levels are higher in neonatal pigs than in adults. Intrarenal artery infusion of pUII reduced kidney perfusion and increased RVR, which was reversed by urantide, a peptide UT inhibitor. One hour of renal ischemia, followed by 8 hours of reperfusion, did not alter kidney tissue UT but upregulated kidney tissue UII and URP and renal vascular UT expression levels. Urantide mitigated renal IR-induced increase in AKI biomarkers. Urantide also attenuated renal IR-induced increases in serum interleukin-1beta, interleukin-10, interferon-α, and morphological kidney injury. The enzyme that converts prepro UII to active UII has been proposed to be serine protease furin. Kidney tissue expression of furin is higher in neonatal pigs compared with adults. Renal IR also upregulated furin expression in neonatal pig kidneys. Exposure of primary neonatal pig renal epithelial cells to the cellular model of IR (cIR) increased furin levels. cIR also increased UII production in the cells, an effect attenuated by furin inhibitor SS3. These findings suggest that in pigs, 1) the UII system is upregulated in immature kidneys, 2) renal IR upregulates furin, UII, and URP in kidney tissues and UT in renal blood vessels of neonates, 3) ischemic activation of furin promotes UII biosynthesis by renal epithelial cells, and 4) pharmacological inhibition of UT mitigates renal IR-induced AKI. We conclude that the UII systems may contribute to IR-induced neonatal renal insuffciency. NIH R01DK120595 R01DK127625. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The effects of the urotensin-II receptor antagonist palosuran treatment on the corpora cavernosa of streptozotocin-induced diabetic rats

ObjectiveTo investigate the effects of treatment with palosuran, a urotensin receptor blocker, on molecular changes in the corpora cavernosa (CC) and erectile function in diabetic rats. MethodsStreptozotocin-induced diabetic rats were treated with palosuran 300 mg/kg per day for 6 weeks. Contraction of CC induced by potassium chloride, phenylephrine, and Nω-Nitro-L-arginine methyl ester and relaxation of CC induced by electric field stimulation (EFS) and sodium nitroprusside (SNP) (endothelium-dependent and endothelium-independent stimuli, respectively), and Y-27632 (Rho-kinase inhibitor) were examined in organ baths. Direct contraction or relaxation induced by palosuran and urotensin-II (U-II) were also evaluated. Expressions of nitric oxide synthetase (NOS) enzymes, RhoA, oxidative stress regulators, and U-II were analyzed by Western blotting or immunohistochemisty. ResultsInduction of diabetes in rats resulted in decreased relaxant response to SNP, decreased pD2 value of SNP, attenuated relaxant response to Y-27632 as well as the decreased RhoA expression in CC. Palosuran treatment of diabetic rats reversed all of these parameters; however, it further impaired the already weakened relaxation of diabetic CC in response to EFS. Although induction of diabetes did not change U-II expression in CC significantly, palosuran treatment reduced U-II expression in diabetic CC. The expression level of nNOS was lowered in diabetic CC; however palosuran treatment did not change the decreased nNOS expression. In vitro exposure of diabetic CC strips to palosuran produced a direct relaxant response. ConclusionPalosuran treatment did not affect the expression of NOS enzymes or reduced nitrergic conduction induced by EFS stimulation in diabetic CC. However, while directly triggering a relaxant response, it did not induce a prominent contraction either by decreasing U-II expression, or increasing the sensitivity of CC to NO which suggested that palosuran has the potential to support erectile function. Further and comprehensive studies are required to clarify this issue.

Urotensin II receptor deficiency ameliorates ligation-induced carotid intimal hyperplasia partially through the RhoA-YAP1 pathway

Intimal hyperplasia (IH) is a common pathological feature of vascular proliferative diseases, such as atherosclerosis and restenosis after angioplasty. Urotensin II (UII) and its receptor (UTR) are widely expressed in cardiovascular tissues. However, it remains unclear whether the UII/UTR system is involved in IH. Right unilateral common carotid artery ligation was performed and maintained for 21 days to induce IH in UTR knockout (UTR−/−) and wild-type (WT) mice. Histological analysis revealed that compared with WT mice, UTR-deficient mice exhibited a decreased neointimal area, angiostenosis and intima–media ratio. Immunostaining revealed fewer smooth muscle cells (SMCs), endothelial cells and macrophages in the lesions of UTR−/− mice than in those of WT mice. Protein interaction analysis suggested that the UTR may affect cell proliferation by regulating YAP and its downstream target genes. In vitro experiments revealed that UII can promote the proliferation and migration of SMCs, and western blotting also revealed that UII increased the protein expression of RhoA, CTGF, Cyclin D1 and PCNA and downregulated p-YAP protein expression, while these effects could be partly reversed by urantide. To evaluate the translational value of UTRs in IH management, WT mice were also treated with two doses of urantide, a UTR antagonist, to confirm the benefit of UTR blockade in IH progression. A high dose of urantide (600 μg/kg/day), rather than a low dose (60 μg/kg/day), successfully improved ligation-induced IH compared with that in mice receiving vehicle. The results of the present study suggested that the UII/UTR system may regulate IH partly through the RhoA-YAP signaling pathway.

The distinctive morphology of caudal neurosecretory system and its impact on Pampus argenteus throughout the breeding season

The caudal neurosecretory system (CNSS) of teleost is intricately linked to reproduction. This study sought to explore the association between the CNSS and the reproductive cycle of Pampus argenteus. Utilizing microscopy and transmission electron microscopy, we observed the morphological alterations within the CNSS. Furthermore, we quantified the levels of urotensin-I (U-I), urotensin-II (U-II), cortisol, and corticotropin-releasing hormone (CRH) throughout the reproductive process. Findings revealed that Dahlgren cells, distributed along the spinal cord adjacent to the terminal 6 vertebrae of the silver pomfret’s tail, were primarily concentrated within the final 3 vertebrae. The neurohypophysis was characterized by an elongated oval form when viewed laterally and an almost spherical configuration in ventral perspective. Post-breeding season, the average diameters of Type I and Type II Dahlgren cells decreased by 21.8% and 15.44%, respectively (P < 0.05), accompanied by a reduction in neurosecretory granules to merely 60% of their initial pre-reproductive state (P < 0.05). Variations in the serum and gonadal concentrations of U-I, U-II, cortisol, and CRH indicated a significant correlation with gonadal maturation. In summary, the CNSS plays a crucial role in gonadal development, directly or indirectly influencing and modulating the reproductive activities of P. argenteus.

Effects of Thymoquinone on Urotensin-II and TGF-β1 Levels in Model of Osteonecrosis in Rats.

Objectives: We aimed to investigate the therapeutic effects of thymoquinone (TMQ) treatment in osteonecrotic rats by evaluating protein levels, osteonecrosis (ON) levels, fatty acid degeneration, oxidative status, and plasma levels of Urotensin-II (U-II) and transforming growth factor-beta (TGF-β1). Materials and Methods: 40 weight-matched adult male Wistar rats were grouped as control (n = 10), methylprednisolone acetate (MPA) (n = 10), thymoquinone (TMQ) (n = 10), and MPA + TMQ (n = 10). To induce ON, 15-week-old animals were subcutaneously injected with MPA at a dose of 15 mg/kg twice weekly for 2 weeks. TMQ was injected into 15-week-old rats via gastric gavage at a dose of 80 mg/kg per day for 4 weeks. The rats in the MPA + TMQ group were administered TMQ 2 weeks before the MPA injection. At the end of the treatments, cardiac blood samples and femur samples were collected for biochemical and histological evaluations. Results: In the control and TMQ groups, no ON pattern was observed. However, in tissues exposed to MPA, TMQ treatment resulted in significantly decreased ON levels compared to the MPA group. The number of cells that were positive for 8-OHdG and 4-HNE was significantly lower in the MPA + TMQ group than in the MPA group (p < 0.05). In terms of TGF-β1 and U-II levels, we observed that both TGF-β1 (367.40 ± 23.01 pg/mL vs. 248.9 ± 20.12 pg/mL) and U-II protein levels (259.5 ± 6.0 ng/mL vs. 168.20 ± 7.90 ng/mL) increased significantly in the MPA group compared to the control group (p < 0.001). Furthermore, TGF-β1 (293.50 ± 14.18 pg/mL) and U-II (174.80 ± 4.2 ng/mL) protein levels were significantly decreased in the MPA + TMQ group compared to the MPA group (p < 0.05 and p < 0.01, respectively). There was a statistically positive correlation (p < 0.05) between the TGF-β1 and U-II protein levels in all groups (p = 0.002, rcontrol = 0.890; p = 0.02, rTMQ = 0.861; p = 0.024, rMPA+TMQ = 0.868) except for the MPA group (p < 0.03, rMedrol = -0.870). Conclusions: As far as we know, this is the first study to demonstrate the curative functions of TMQ on ON by causing a correlated decrease in the expression of U-II and TGF-β1 in the femoral heads of rats.

Urotensin II Receptor Modulation with 1,3,4-Benzotriazepin-2-one Tetrapeptide Mimics.

Urotensin II receptor (UT) modulators that differentiate the effects of the endogenous cyclic peptide ligands urotensin II (UII) and urotensin II-related peptide (URP) offer potential for dissecting their respective biological roles in disease etiology. Selective modulators of hUII and URP activities were obtained using 1,3,4-benzotriazepin-2-one mimics of a purported bioactive γ-turn conformation about the Bip-Lys-Tyr tripeptide sequence of urocontrin ([Bip4]URP). Considering an active β-turn conformer about the shared Phe-Trp-Lys-Tyr sequence of UII and URP, 8-substituted 1,3,4-benzotriazepin-2-ones were designed to mimic the Phe-Bip-Lys-Tyr tetrapeptide sequence of urocontrin, synthesized, and examined for biological activity. Subtle 5- and 8-position modifications resulted in biased signaling and selective modulation of hUII- or URP-induced vasoconstriction. For example, p-hydroxyphenethyl analogs 17b-d were strong Gα13 and βarr1 activators devoid of Gαq-mediated signaling. Tertiary amides 15d and 17d negatively modulated hUII-induced vasoconstriction without affecting URP-mediated responses. Benzotriazepinone carboxamides proved to be exceptional tools for elucidating the pharmacological complexity of UT.

Investigation of the effects of urotensin II receptors in LPS-induced inflammatory response in HUVEC cell line through calcineurin/NFATc/IL-2 pathway

PurposeThe effect of urotensin II (U-II), a powerful endogenous vasoconstrictor substance, on the immune system and its mediators is very important.It was herein aimed to demonstrate the possible relationship between the calcineurin/nuclear factor of activated T-cells cytoplasmic 1/interleukin-2 (CaN/NFATc/IL-2) pathway and urotensin receptors (UTRs) in inflammatory response due to lipopolysaccharide (LPS). MethodsAn LPS-induced inflammation model was used on the human umbilical vein endothelial cells (HUVEC) cell line and drugs were applied accordingly, forming the following groups: Control Group, LPS Group, Agonist Group (10−8 ​M U-II), Antagonist Group (10−6 ​M palosuran), Tacrolimus (TAC) Group (10 ​ng/mL FK-506), Agonist ​+ ​TAC Group, and Antagonist ​+ ​TAC Group. Gene expression analyses were performed using real-time polymerase chain reaction (RT-PCR). ResultsIn the analysis of the cell viability at 48 and 72 ​h, there was a decrease in the Agonist Group, while in the Agonist ​+ ​TAC Group, the cell viability increased. In the Antagonist Group, cell viability was maintained when compared to the LPS Group, while in the TAC Group, this effect was reduced. The mRNA expression levels of UTR, CaN, NFATc, IL-2 receptor (IL-2R), IL-6 and nuclear factor kappa B (NF-κB) were higher in the LPS Group than in the Control Group, and even the UTR, CaN, NFATc, IL-2R were higher with agonist administration. This effect of the agonist was shown to be completely mitigated in the presence of the CaN inhibitor. ConclusionU-II and its receptors can perform key functions regarding the endothelial cell damage via the CaN/NFATc/IL-2 pathway.

Smad2/3 signaling involved in urotensin II-induced phenotypic differentiation, collagen synthesis and migration of rat aortic adventitial fibroblasts

Objective. To investigate whether Smad2/3 signaling is involved in urotensin II (UII) induced activation of aortic adventitial fibroblasts. Materials and Methods. Growth-arrested adventitial fibroblasts were stimulated with UII in the presence or absence of urotensin II receptor (UT) antagonist SB710411 or transfected with Smad2/3 small inhibitory RNA (siRNA). UII stimulated Smad2/3 phosphorylation, α-smooth muscle actin (α-SMA), and collagen I expression and migration of adventitial fibroblasts were evaluated by western blot analysis, real-time reverse transcription polymerase chain reaction, immunofluorescence, ELISA, and transwell migration assay, respectively. Results. In cultured adventitial fibroblasts, UII time- and dose-dependently stimulated Smad2/3 protein phosphorylation, with maximal effect at 10-8 mol/l (increased by 147.2%, P&lt;0.001). UII stimulated Smad2/3 upregulation and nuclear translocation. SB710411 significantly inhibited these effects. In addition, UII potently induced α-SMA and procollagen 1 protein or mRNA expression (P&lt;0.01), which were completely blocked by Smad2 (decreased by 75.1%, 54.2% in protein, and by 73.3% and 38.2% in mRNA, respectively, P&lt;0.01) or Smad3 siRNA (decreased by 80.3% and 47.0% in protein, and by 72.3% and 47.7% in mRNA, respectively, P&lt;0.01). Meanwhile, Smad2 or smad3 siRNA significantly inhibited the UII-induced collagen 1 secretion and cell migration. Conclusions. UII may stimulate adventitial-fibroblast phenotype conversion, migration, and collagen I synthesis via phosphorylated-Smad2/3 signal transduction pathways.

Serum Urotensin II Levels Are Elevated in Patients with Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) has become major public concern and is continuously investigated in new aspects of pathophysiology and management. Urotensin II (UII) is a powerful vasoconstrictor with a role in cardiovascular diseases. The main goal of this study was to evaluate serum UII levels in OSA patients and matched controls. A total of 89 OSA patients and 89 controls were consecutively enrolled. A medical history review and physical examination of the participants was conducted, with polysomnography performed in the investigated group. UII levels and other biochemical parameters were assessed according to the standard laboratory protocols. The median AHI in the OSA group was 39.0 (31.4-55.2) events/h, and they had higher levels of hsCRP when compared to control group (2.87 ± 0.71 vs. 1.52 ± 0.68 mg/L; p < 0.001). Additionally, serum UII levels were significantly higher in the OSA group (3.41 ± 1.72 vs. 2.18 ± 1.36 ng/mL; p < 0.001), while positive correlation was found between UII levels and hsCRP (r = 0.450; p < 0.001) and systolic blood pressure (SPB) (r = 0.317; p < 0.001). Finally, multiple regression analysis showed significant association of UII levels with AHI (0.017 ± 0.006, p = 0.013), SBP (0.052 ± 0.008, p < 0.001) and hsCRP (0.538 ± 0.164, p = 0.001). As UII levels were associated with blood pressure and markers of inflammation and OSA severity, it might play an important role in the complex pathophysiology of OSA and its cardiometabolic complications.

Urotensin receptor in GtoPdb v.2023.1

The urotensin-II (U-II) receptor (UT, nomenclature as agreed by the NC-IUPHAR Subcommittee on the Urotensin receptor [26, 36, 94]) is activated by the endogenous dodecapeptide urotensin-II, originally isolated from the urophysis, the endocrine organ of the caudal neurosecretory system of teleost fish [7, 93]. Several structural forms of U-II exist in fish and amphibians [94]. The goby orthologue was used to identify U-II as the cognate ligand for the predicted receptor encoded by the rat gene gpr14 [2, 20, 63, 69, 72]. Human urotensin-II, an 11-amino-acid peptide [20], retains the cyclohexapeptide sequence of goby U-II that is thought to be important in ligand binding [61, 53, 10]. This sequence is also conserved in the deduced amino-acid sequence of rat urotensin-II (14 amino-acids) and mouse urotensin-II (14 amino-acids), although the N-terminal is more divergent from the human sequence [19]. A second endogenous ligand for the UT has been discovered in rat [86]. This is the urotensin II-related peptide, an octapeptide that is derived from a different gene, but shares the C-terminal sequence (CFWKYCV) common to U-II from other species. Identical sequences to rat urotensin II-related peptide are predicted for the mature mouse and human peptides [32]. UT exhibits relatively high sequence identity with somatostatin, opioid and galanin receptors [94]. The urotensinergic system displays an unprecedented repertoire of four or five ancient UT in some vertebrate lineages and five U-II family peptides in teleost fish [91].

Urotensin II can Induce Skeletal Muscle Atrophy Associated with Upregulating Ubiquitin-Proteasome System and Inhibiting the Differentiation of Satellite Cells in CRF Mice.

Skeletal muscle wasting and atrophy is highly prevalent in chronic renal failure (CRF) and increases the risk of mortality. According to our previous study, we speculate that urotensin II (UII) can induce skeletal muscle atrophy by upregulating ubiquitin-proteasome system(UPS) in CRF. C2C12 mouse myoblast cells were differentiated into myotubes, and myotubes were exposed to different concentrations of UII. Myotube diameters, myosin heavy chain(MHC), p-Fxo03A, skeletal muscle-specific E3 ubiquitin ligases such as muscle RING finger 1 (MuRF1) and muscle atrophy F-box (MAFbx/atrogin1) were detected. Three animal models (the sham operation mice as normal control (NC) group, wild-type C57BL/6 mice with 5/6 nephrectomy (WT CRF) group, UII receptor gene knock out (UT KO) mice with 5/6 nephrectomy (UT KO CRF) group) were designed. Cross-sectional area (CSA) of skeletal muscle tissues in three animal models were measured, and western blot detected protein of UII, p-Fxo03A, MAFbx and MuRF1, and immunofluorescence assays explored the satellite cell marker of Myod1 and Pax7, and PCR arrays detected the muscle protein degradation genes, protein synthesis genes and the genes which were involved in muscle components. UII could decrease mouse myotube diameters, and upregulate dephosphorylated Fxo03A protein. MAFbx and MuRF1 were higher in WT CRF group than that in NC group, but after UII receptor gene was knocked out (UT KO CRF), their expressions were downregulated. UII could inhibit the expression of Myod1 but not Pax7 in animal study. We first demonstrate that skeletal muscle atrophy induced by UII associated with upregulating ubiquitin-proteasome system and inhibiting the differentiation of satellite cells in CRF mice.

Exploration of the urocontrin A scaffold yields new urotensinergic system allosteric modulator and competitive antagonists

The urotensinergic system, involved in the development and/or progression of numerous pathological conditions, is composed of one G protein-coupled receptor (UT) and two endogenous ligands known as urotensin II (UII) and urotensin II-related peptide (URP). These two structurally related hormones, which exert common and divergent effects, are thought to play specific biological roles. In recent years, we have characterized an analog termed urocontrin A (UCA), i.e. [Pep4]URP, which is capable of discriminating the effects of UII from URP. Such an action could allow the delineation of the respective functions of these two endogenous ligands. In an effort to define the molecular determinants involved in this behavior and to improve the pharmacological profile of UCA, we introduced modifications from urantide, considered for some time as a lead compound for the development of UT antagonists, into UCA and assessed the binding, contractile activity and G protein signaling of these newly developed compounds. Our results show that UCA and its derivatives exert probe-dependent effects on UT antagonism, and we have further identified [Pen2, Pep4]URP as a Gq biased ligand with an insurmountable antagonism in our aortic ring contraction assay.

Urotensin II Enhances Advanced Aortic Atherosclerosis Formation and Delays Plaque Regression in Hyperlipidemic Rabbits.

Accumulated evidence shows that elevated urotensin II (UII) levels are associated with cardiovascular diseases. However, the role of UII in the initiation, progression, and regression of atherosclerosis remains to be verified. Different stages of atherosclerosis were induced in rabbits by a 0.3% high cholesterol diet (HCD) feeding, and either UII (5.4 μg/kg/h) or saline was chronically infused via osmotic mini-pumps. UII promoted atherosclerotic fatty streak formation in ovariectomized female rabbits (34% increase in gross lesion and 93% increase in microscopic lesion), and in male rabbits (39% increase in gross lesion). UII infusion significantly increased the plaque size of the carotid and subclavian arteries (69% increase over the control). In addition, UII infusion significantly enhanced the development of coronary lesions by increasing plaque size and lumen stenosis. Histopathological analysis revealed that aortic lesions in the UII group were characterized by increasing lesional macrophages, lipid deposition, and intra-plaque neovessel formation. UII infusion also significantly delayed the regression of atherosclerosis in rabbits by increasing the intra-plaque macrophage ratio. Furthermore, UII treatment led to a significant increase in NOX2 and HIF-1α/VEGF-A expression accompanied by increased reactive oxygen species levels in cultured macrophages. Tubule formation assays showed that UII exerted a pro-angiogenic effect in cultured endothelial cell lines and this effect was partly inhibited by urantide, a UII receptor antagonist. These findings suggest that UII can accelerate aortic and coronary plaque formation and enhance aortic plaque vulnerability, but delay the regression of atherosclerosis. The role of UII on angiogenesis in the lesion may be involved in complex plaque development.

Protective effect of urotensin II receptor antagonist urantide and exercise training on doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) has a wide antitumor spectrum, but its adverse cardiotoxicity may lead to heart failure. Urotensin II (UII) is the most potent vasoconstrictor in mammals. It plays a role by activating the UII receptor (UT), the orphan G protein-coupled receptor (GPR14), collectively referred to as the UII/UT system. In the new version of "Chinese expert consensus on cardiac rehabilitation of chronic heart failure," it is pointed out that exercise rehabilitation is the cornerstone of cardiac rehabilitation. In this study, in vitro and in vivo assessments were performed using DOX-treated H9C2 cells and rats. It was found that the UT antagonist Urantide and exercise training improved DOX-induced cardiac insufficiency, reduced DOX-induced cardiomyocyte apoptosis, improved the structural disorder of myocardial fibers, and inhibited DOX-induced myocardial fibrosis. Further studies showed that Urantide alleviated DOX-induced cardiotoxicity by downregulating the expression levels of the p38 mitogen-activated protein kinase signaling pathway.

Dynamic changes of urotensin II and its receptor during ovarian development of olive flounder Paralichthys olivaceus.

Urotensin II (UII) is a kind of fish somatostatins cyclic peptide, which was originally extracted from the caudal neurosecretory system (CNSS). The system of UII and UII receptor (UIIR) has been reported to have multiple physiological regulatory functions, such as cardiovascular control, osmoregulation, and lipid metabolism. However, the effect of UII and UIIR on the ovarian development has not been covered. This study investigated the expression pattern of UII and UIIR in the ovarian follicles and explored their impact on ovarian development in olive flounder Paralichthys olivaceus. The results showed that the highest UII and UIIR mRNA levels were observed at stage II and stage III follicles during ovarian development, respectively. In situ hybridization revealed that a strong signal of UII was expressed in the oocyte nuclei of stage II follicles, however, UIIR was found in the follicle cells and oocyte cytoplasm of stage II and stage III follicles. Similarly, immunohistochemistry found positive signal of UII was detected in the oocyte nuclei of stage II follicles. The results from in vitro culture of olive flounder follicles suggested the expression of UII and UIIR mRNA levels significantly increased by 10IU/ml human chorionic gonadotropin (hCG) for 9h. Furthermore, the transcriptional expression of UII and UIIR was not statistically significantly changed by 17α, 20β-dihydroxy-4-pregnen-3-one (DHP). These results firstly suggested that UII and UII receptor may play vital roles in regulating ovarian growth in olive flounder.

Globular adiponectin-mediated vascular remodeling by affecting the secretion of adventitial-derived tumor necrosis factor-α induced by urotensin II.

In this study, we explored how adiponectin mediated urotensin II (UII)‍-induced tumor necrosis factor-‍α (TNF-‍α) and α‍-smooth muscle actin (α‍-SMA) expression and ensuing intracellular signaling pathways in adventitial fibroblasts (AFs). Growth-arrested AFs and rat tunica adventitia of vessels were incubated with UII and inhibitors of signal transduction pathways for 1‍‒‍24 h. The cells were then harvested for TNF-α receptor (TNF-‍α-R) messenger RNA (mRNA) and TNF-‍α protein expression determination by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Adiponectin and adiponectin receptor (adipoR) expression was measured by RT-PCR, quantitative real-time PCR (qPCR), immunohistochemical analysis, and cell counting kit-8 (CCK-8) cell proliferation experiments. We then quantified TNF-α and α-SMA mRNA and protein expression levels by qPCR and immunofluorescence (IF) staining. RNA interference (RNAi) was used to explore the function of the adipoR genes. To investigate the signaling pathway, we applied western blotting (WB) to examine phosphorylation of adenosine 5'-monophosphate (AMP)‍-activated protein kinase (AMPK). In vivo, an adiponectin (APN)‍-knockout (APN-KO) mouse model mimicking adventitial inflammation was generated to measure TNF-α and α‍-SMA expression by application of qPCR and IF, with the goal of gaining a comprehensive atlas of adiponectin in vascular remodeling. In both cells and tissues, UII promoted TNF-α protein and TNF-α-R secretion in a dose- and time-dependent manner via Rho/protein kinase C (PKC) pathway. We detected marked expression of adipoR1, T-cadherin, and calreticulin as well as a moderate presence of adipoR2 in AFs, while no adiponectin was observed. Globular adiponectin (gAd) fostered the growth of AFs, and acted in concert with UII to induce α-SMA and TNF-α through the adipoR1/T-cadherin/calreticulin/AMPK pathway. In AFs, gAd and UII synergistically induced AMPK phosphorylation. In the adventitial inflammation model, APN deficiency up-regulated the expression of α-SMA, UII receptor (UT), and UII while inhibiting TNF-‍α expression. From the results of our study, we can speculate that UII induces TNF‍-‍α protein and TNF-‍α‍-R secretion in AFs and rat tunica adventitia of vessels via the Rho and PKC signal transduction pathways. Thus, it is plausible that adiponectin is a major player in adventitial progression and could serve as a novel therapeutic target for cardiovascular disease administration.

The Inhibitory Role of Hydrogen Sulfide in UII-Induced Cardiovascular Effects and the Underlying Signaling Pathways.

Urotensin II (UII) could increase blood pressure and heart rate via increased central reactive oxygen species (ROS) levels. We reported previously that hydrogen sulfide (H2S) exerts an antihypertensive effect by suppressing ROS production. The aim of the current study is to further examine the effects of endogenous and exogenous H2S on UII-induced cardiovascular effects by using an integrated physiology approach. We also use cell culture and molecular biological techniques to explore the inhibitory role of H2S on UII-induced cardiovascular effects. In this study, we found that cystathionine-β-synthase (CBS), the main H2S synthesizing enzyme in CNS, was expressed in neuronal cells of the rostral ventrolateral medulla (RVLM) area. Cellular distribution of CBS and urotensin II receptor (UT) in SH-SY5Y cells that are confirmed as glutamatergic were identified by immunofluorescent and Western blots assay. In Sprague-Dawley rats, administration of UII into the RVLM resulted in an increase in mean arterial pressure (MAP), heart rate (HR), ROS production, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and phosphorylation of p47phox, extracellular signal-regulated protein kinase (ERK)1/2 and p38MAPK, but not stress-activated protein kinase/Jun N-terminal kinase (SAPK/JNK). These effects of UII were attenuated by application into the RVLM of endogenous (L-cysteine, SAM) or exogenous (NaHS) H2S. These results were confirmed in SH-SY5Y cells. UII-induced cardiovascular effects were also significantly abolished by pretreatment with microinjection of Tempol, Apocynin, SB203580, or PD98059 into the RVLM. Preincubated SH-SY5Y cells with Apocynin before administration of UII followed by Western blots assay showed that ROS is in the upstream of p38MAPK/ERK1/2. Gao activation assay in SH-SY5Y cells suggested that H2S may exert an inhibitory role on UII-induced cardiovascular effects by inhibiting the activity of Gαo. These results suggest that both endogenous and exogenous H2S attenuate UII-induced cardiovascular effects via Gαo-ROS-p38MAPK/ERK1/2 pathway.

Urotensin receptor acts as a novel target for ameliorating fasting-induced skeletal muscle atrophy

Urotensin receptor (UT) is a G-protein-coupled receptor, whose endogenous ligand is urotensin-II (U-II). Skeletal muscle mass is regulated by various conditions, such as nutritional status, exercise, and diseases. Previous studies have pointed out that the urotensinergic system is involved in skeletal muscle metabolism and function, but its mechanism remains unclear, especially given the lack of research on the effect and mechanism of fasting. In this study, UT receptor knockout mice were generated to evaluate whether UT has effects on fasting induced skeletal muscle atrophy. Furthermore, the UT antagonist palosuran (3, 10, 30 mg/kg) was intraperitoneally administered daily for 5 days to clarify the therapeutic effect of UT antagonism. Our results found the mice that fasted for 48 h exhibited skeletal muscle atrophy, accompanied by enhanced U-II levels in both skeletal muscles and blood. UT receptor knockout effectively prevented fasting-induced skeletal muscle atrophy. The UT antagonist ameliorated fasting-induced muscle atrophy in mice as determined by increased muscle strengths, weights, and muscle fiber areas (including fast, slow, and mixed types). In addition, the UT antagonist reduced skeletal muscle atrophic markers, including F-box only protein 32 (FBXO32) and tripartite motif containing 63 (TRIM63). Moreover, the UT antagonist was also observed to enhance PI3K/AKT/mTOR while inhibiting autophagy signaling. In summary, our study provides the first evidence that UT antagonism may represent a novel therapeutic approach for the treatment of fasting-induced skeletal muscle atrophy.

Urotensin II level is elevated in inflammatory bowel disease patients.

It was reported that the urotensin II (U-II) level in inflammatory bowel disease (IBD) patients are significantly higher than in controls. To provide future guidance for the management of cardiovascular risk factors in IBD patients, the sample size of the current study appears to be limited, and more clinical samples to compare U-II levels in IBD patients and controls are needed. This will clarify the possible roles of inflammation factors and related signaling pathways (like EPK1/2, NF-κB and Rho/ROCK) in the pathophysiology of IBD. Therefore, large multicenter studies should be done to confirm the findings and underlying mechanisms in the future.