GLP-1 in the Hypothalamic Paraventricular Nucleus Promotes Sympathetic Activation and Hypertension.

Glucagon-like peptide-1 (GLP-1) and its analogs are widely used for diabetes treatment. The paraventricular nucleus (PVN) is crucial for regulating cardiovascular activity. This study aims to determine the roles of GLP-1 and its receptors (GLP-1R) in the PVN in regulating sympathetic outflow and blood pressure. Experiments were carried out in male normotensive rats and spontaneously hypertensive rats (SHR). Renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded. GLP-1 and GLP-1R expressions were present in the PVN. PVN microinjection of GLP-1R agonist recombinant human GLP-1 (rhGLP-1) or EX-4 increased RSNA and MAP, which were prevented by GLP-1R antagonist exendin 9-39 (EX9-39) or GLP-1R antagonist 1, superoxide scavenger tempol, antioxidant N-acetylcysteine, NADPH oxidase (NOX) inhibitor apocynin, adenylyl cyclase (AC) inhibitor SQ22536 or protein kinase A (PKA) inhibitor H89. PVN microinjection of rhGLP-1 increased superoxide production, NADPH oxidase activity, cAMP level, AC, and PKA activity, which were prevented by SQ22536 or H89. GLP-1 and GLP-1R were upregulated in the PVN of SHR. PVN microinjection of GLP-1 agonist increased RSNA and MAP in both WKY and SHR, but GLP-1 antagonists caused greater effects in reducing RSNA and MAP in SHR than in WKY. The increased superoxide production and NADPH oxidase activity in the PVN of SHR were augmented by GLP-1R agonists but attenuated by GLP-1R antagonists. These results indicate that activation of GLP-1R in the PVN increased sympathetic outflow and blood pressure via cAMP-PKA-mediated NADPH oxidase activation and subsequent superoxide production. GLP-1 and GLP-1R upregulation in the PVN partially contributes to sympathetic overactivity and hypertension.

FNDC5 inhibits malignant growth of human cervical cancer cells via restraining PI3K/AKT pathway.

Cervical cancer (CxCa) is the fourth most frequent cancer in women. This study aimed to determine the role and underlying mechanism of fibronectin type III domain-containing protein 5 (FNDC5) in inhibiting CxCa growth. Experiments were performed in human CxCa tissues, human CxCa cell lines (HeLa and SiHa), and xenograft mouse model established by subcutaneous injection of SiHa cells in nude mice. Bioinformatics analysis showed that CxCa patients with high FNDC5 levels have a longer overall survival period. FNDC5 expression was increased in human CxCa tissues, HeLa and SiHa cells. FNDC5 overexpression or FNDC5 protein not only inhibited proliferation, but also restrained invasion and migration of HeLa and SiHa cells. The effects of FNDC5 were prevented by inhibiting integrin with cilengitide, activating PI3K with recilisib or activating Akt with SC79. FNDC5 inhibited the phosphorylation of PI3K and Akt, which was attenuated by recilisib. PI3K inhibitor LY294002 showed similar effects to FNDC5 in HeLa and SiHa cells. Intravenous injection of FNDC5 (20 µg/day) for 14 days inhibited the tumor growth, and reduced the proliferation marker Ki67 expression and the Akt phosphorylation in the CxCa xenograft mouse model. These results indicate that FNDC5 inhibits the malignant phenotype of CxCa cells through restraining PI3K/Akt signaling. Upregulation of FNDC5 may play a beneficial role in retarding the tumor growth of CxCa.

Anatomical and functional evidence for renal autonomic innervation in normotensive and hypertensive rats.

Renal denervation (RDN) has been used for treating resistant hypertension. A few recent studies show vagal innervation of kidneys causing confusion. This study aimed to provide anatomical and functional evidence for renal autonomic innervation. Experiments were performed in male Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Pseudorabies virus (PRV) in paraventricular nucleus and rostral ventrolateral medulla was prevented by bilateral RDN, but not subdiaphragmatic vagotomy. PRV did not appear in dorsal motor nucleus of vagus and nucleus tractus solitarii 72 h after renal injection of PRV. Adrenergic fibers were approximately 7 times more than cholinergic fibers in main renal artery (MRA) and its first (1RA) and second grade (2RA) branches. Adrenergic fibers in 1RA were more than these in MRA and 2RA. Tyrosine hydroxylase immunoreactivity in these arteries was higher in SHR than WKY. Norepinephrine (NE) increased, and α-receptor antagonist reduced vascular ring tension of renal arteries. The effect of NE was greater in 1RA and 2RA than MRA, which was prevented by α-receptor antagonist. Acetylcholine (ACh) or blockage of ß-receptors, M- or N-receptors had no significant effects on vascular ring tension and the effect of NE. Renal blood flow was reduced by electrical stimulation of renal nerves, but not affected by stimulation of subdiaphragmatic vagus. These results provide anatomical and functional evidence that kidneys are innervated and renal blood flow is regulated by renal sympathetic nerves rather than vagus. Renal vasoconstriction is regulated by NE and adrenergic fibers rather than ACh or cholinergic fibers in WKY and SHR.

Chemerin in caudal division of nucleus tractus solitarius increases sympathetic activity and blood pressure.

Chemerin is an adipokine that contributes to metabolism regulation. Nucleus tractus solitarius (NTS) is the first relay station in the brain for accepting various visceral afferent activities for regulating cardiovascular activity. However, the roles of chemerin in the NTS in regulating sympathetic activity and blood pressure are almost unknown. This study aimed to determine the role and potential mechanism of chemerin in the NTS in modulating sympathetic outflow and blood pressure. Bilateral NTS microinjections were performed in anaesthetized adult male Sprague-Dawley rats. Renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP) and heart rate (HR) were continuously recorded. Chemerin and its receptor chemokine-like receptor 1 (CMKLR1) were highly expressed in caudal NTS (cNTS). Microinjection of chemerin-9 to the cNTS increased RSNA, MAP and HR, which were prevented by CMKLR1 antagonist α-NETA, superoxide scavenger tempol or N-acetyl cysteine, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors diphenyleneiodonium or apocynin. Chemerin-9 increased superoxide production and NADPH oxidase activity in the cNTS. The increased superoxide production induced by chemerin-9 was inhibited by α-NETA. The effects of cNTS microinjection of chemerin-9 on the RSNA, MAP and HR were attenuated by the pretreatment with paraventricular nucleus (PVN) microinjection of NMDA receptor antagonist MK-801 rather than AMPA/kainate receptor antagonist CNQX. These results indicate that chemerin-9 in the NTS increases sympathetic outflow, blood pressure and HR via CMKLR1-mediated NADPH oxidase activation and subsequent superoxide production in anaesthetized normotensive rats. Glutamatergic inputs in the PVN are needed for the chemerin-9-induced responses.

Casein kinase 1 AELs promote senescence by enhancing ethylene biosynthesis through phosphorylating WRKY22 transcription factor.

Leaf senescence is a complex process regulated by developmental and environmental factors, and plays a pivotal role in the development and life cycle of higher plants. Casein kinase 1 (CK1) is a highly conserved serine/threonine protein kinase in eukaryotes and functions in various cellular processes including cell proliferation, light signaling and hormone effects of plants. However, the biological function of CK1 in plant senescence remains unclear. Through systemic genetic and biochemical studies, we here characterized the function of Arabidopsis EL1-like (AEL), a CK1, in promoting leaf senescence by stimulating ethylene biosynthesis through phosphorylating transcription factor WRKY22. Seedlings lacking or overexpressing AELs presented delayed or accelerated leaf senescence, respectively. AELs interact with and phosphorylate WRKY22 at Thr57, Thr60 and Ser69 residues to enhance whose transactivation activity. Being consistent, increased or suppressed phosphorylation of WRKY22 resulted in the promoted or delayed leaf senescence. WRKY22 directly binds to promoter region and stimulates the transcription of 1-amino-cyclopropane-1-carboxylate synthase 7 gene to promote ethylene level and hence leaf senescence. Our studies demonstrated the crucial role of AEL-mediated phosphorylation in regulating ethylene biosynthesis and promoting leaf senescence by enhancing WRKY22 transactivation activity, which helps to elucidate the fine-controlled ethylene biosynthesis and regulatory network of leaf senescence.

Cardiomyocyte-specific Peli1 contributes to the pressure overload-induced cardiac fibrosis through miR-494-3p-dependent exosomal communication.

Cardiac fibrosis is an essential pathological process in pressure overload (PO)-induced heart failure. Recently, myocyte-fibroblast communication is proven to be critical in heart failure, in which, pathological growth of cardiomyocytes (CMs) may promote fibrosis via miRNAs-containing exosomes (Exos). Peli1 regulates the activation of NF-κB and AP-1, which has been demonstrated to engage in miRNA transcription in cardiomyocytes. Therefore, we hypothesized that Peli1 in CMs regulates the activation of cardiac fibroblasts (CFs) through an exosomal miRNA-mediated paracrine mechanism, thereby promoting cardiac fibrosis. We found that CM-conditional deletion of Peli1 improved PO-induced cardiac fibrosis. Moreover, Exos from mechanical stretch (MS)-induced WT CMs (WT MS-Exos) promote activation of CFs, Peli1-/- MS-Exos reversed it. Furthermore, miRNA microarray and qPCR analysis showed that miR-494-3p was increased in WT MS-Exos while being down regulated in Peli1-/- MS-Exos. Mechanistically, Peli1 promoted miR-494-3p expression via NF-κB/AP-1 in CMs, and then miR-494-3p induced CFs activation by inhibiting PTEN and amplifying the phosphorylation of AKT, SMAD2/3, and ERK. Collectively, our study suggests that CMs Peli1 contributes to myocardial fibrosis via CMs-derived miR-494-3p-enriched exosomes under PO, and provides a potential exosomal miRNA-based therapy for cardiac fibrosis.

Angiotensin II-induced miR-31-5p upregulation promotes vascular smooth muscle cell proliferation and migration.

Angiotensin II (Ang II) plays a central role in vascular smooth muscle cell (VSMC) proliferation and migration, being key to regulate vascular function and promote vascular remodeling in cardiovascular diseases. We recently showed that miR-31-5p promoted oxidative stress in spontaneously hypertensive rats. In this study, we aim to investigate whether miR-31-5p and fibronectin type III domain-containing 5 (FNDC5) contribute to Ang II-induced VSMC proliferation and migration. Experiments were performed in primary VSMCs of wide-type (WT) and FNDC5-/- mice as well as the rat A7r5 cell line. We found that Ang II increased miR-31-5p level, reduced FNDC5 expression and stimulated VSMC proliferation and migration, which were aggravated by miR-31-5p mimic, and prevented by miR-31-5p inhibitor in VSMCs. The Ang II-induced VSMC proliferation were prevented by exogenous FNDC5 in both WT and FNDC5-/- mice, while the effects were more significant in FNDC5-/- mice. Furthermore, exogenous FNDC5 reversed the effects of miR-31-5p mimic on VSMC proliferation and migration in Ang II-treated VSMCs. Meanwhile, FNDC5 deficiency prevented the effects of miR-31-5p inhibitor on VSMC proliferation and migration in Ang II-treated VSMCs. In conclusion, our findings demonstrate that the miR-31-5p upregulation and the following FNDC5 downregulation contribute to Ang II-induced VSMC proliferation and migration.

[Effect of Shionone on Neuron Apoptosis After Spinal Cord Injury in Mice].

Objective To explore the effect of shionone(SHI)on motor function in the mouse model of spinal cord injury(SCI)and probe into the underlying molecular mechanism.Methods C57BL/6 mice were treated to induce the SCI model and then assigned into a model group(SCI group),a SCI+SHI group,and a sham surgery(control)group.The Basso mouse scale(BMS)score was determined to evaluate the recovery of motor function in SCI mice.Hematoxylin-eosin(HE)staining,Nissl staining,and immunofluorescence staining were employed to examine the fibrosis,morphological changes of neurons,and neuron apoptosis in the spinal cord tissue of SCI mice,respectively.The mouse hippocampal neuronal cell line HT22 was cultured in vitro and then classified into tumor necrosis factor α(TNF-α)induction and SHI groups.Western blotting was employed to determine the expression of apoptosis-associated proteins.Network pharmacology,gene ontology annotation,and Kyoto Encyclopedia of Genes and Genomes pathway enrichment were employed to predict the possible molecular targets and signaling pathways of SHI in promoting functional recovery from SCI.Furthermore,the prediction results were verified by in vitro and in vivo experiments.Results Compared with the SCI group,the SCI+SHI group showed increased BMS score on days 21,28,35,and 42(P=0.003,P=0.004,P=0.023,and P=0.007,respectively),reduced area of spinal cord fibrosis(P=0.021),increased neurons survived(P=0.001),and down-regulated expression of cleaved cysteine aspastic acid-specific protease 3(cleaved Caspase-3)(P=0.017).Compared with the TNF-α group,the SHI group presented down-regulated expression levels of cleaved Caspase-3 and Bax(P=0.010,P=0.001)and up-regulated expression level of Bcl-2(P=0.001).The results of bioinformatics analysis showed that SHI might improve the motor function of SCI mice via the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)signaling pathway.The results of in vivo and in vitro experiments showed that SHI inhibited the phosphorylation of PI3K and Akt in SCI mice or HT22 cells exposed to TNF-α(all P<0.05).The number of apoptotic HT22 cells after treatment with insulin-like growth factor 1 was higher than that in the SHI group(P=0.003).Conclusion SHI may inhibit neuron apoptosis via the PI3K/Akt signaling pathway,thereby promoting the recovery of motor function in SCI mice.

Extracellular vesicles in vascular remodeling.

Vascular remodeling contributes to the development of a variety of vascular diseases including hypertension and atherosclerosis. Phenotypic transformation of vascular cells, oxidative stress, inflammation and vascular calcification are closely associated with vascular remodeling. Extracellular vesicles (EVs) are naturally released from almost all types of cells and can be detected in nearly all body fluids including blood and urine. EVs affect vascular oxidative stress, inflammation, calcification, and lipid plaque formation; and thereby impact vascular remodeling in a variety of cardiovascular diseases. EVs may be used as biomarkers for diagnosis and prognosis, and therapeutic strategies for vascular remodeling and cardiovascular diseases. This review includes a comprehensive analysis of the roles of EVs in the vascular remodeling in vascular diseases, and the prospects of EVs in the diagnosis and treatment of vascular diseases.

Chronic infusion of ELABELA alleviates vascular remodeling in spontaneously hypertensive rats via anti-inflammatory, anti-oxidative and anti-proliferative effects.

Inflammatory activation and oxidative stress promote the proliferation of vascular smooth muscle cells (VSMCs), which accounts for pathological vascular remodeling in hypertension. ELABELA (ELA) is the second endogenous ligand for angiotensin receptor-like 1 (APJ) receptor that has been discovered thus far. In this study, we investigated whether ELA regulated VSMC proliferation and vascular remodeling in spontaneously hypertensive rats (SHRs). We showed that compared to that in Wistar-Kyoto rats (WKYs), ELA expression was markedly decreased in the VSMCs of SHRs. Exogenous ELA-21 significantly inhibited inflammatory cytokines and NADPH oxidase 1 expression, reactive oxygen species production and VSMC proliferation and increased the nuclear translocation of nuclear factor erythroid 2-related factor (Nrf2) in VSMCs. Osmotic minipump infusion of exogenous ELA-21 in SHRs for 4 weeks significantly decreased diastolic blood pressure, alleviated vascular remodeling and ameliorated vascular inflammation and oxidative stress in SHRs. In VSMCs of WKY, angiotensin II (Ang II)-induced inflammatory activation, oxidative stress and VSMC proliferation were attenuated by pretreatment with exogenous ELA-21 but were exacerbated by ELA knockdown. Moreover, ELA-21 inhibited the expression of matrix metalloproteinase 2 and 9 in both SHR-VSMCs and Ang II-treated WKY-VSMCs. We further revealed that exogenous ELA-21-induced inhibition of proliferation and PI3K/Akt signaling were amplified by the PI3K/Akt inhibitor LY294002, while the APJ receptor antagonist F13A abolished ELA-21-induced PI3K/Akt inhibition and Nrf2 activation in VSMCs. In conclusion, we demonstrate that ELA-21 alleviates vascular remodeling through anti-inflammatory, anti-oxidative and anti-proliferative effects in SHRs, indicating that ELA-21 may be a therapeutic agent for treating hypertension.

Asprosin in the Paraventricular Nucleus Induces Sympathetic Activation and Pressor Responses via cAMP-Dependent ROS Production.

Asprosin is a newly discovered adipokine that is involved in regulating metabolism. Sympathetic overactivity contributes to the pathogenesis of several cardiovascular diseases. The paraventricular nucleus (PVN) of the hypothalamus plays a crucial role in the regulation of sympathetic outflow and blood pressure. This study was designed to determine the roles and underlying mechanisms of asprosin in the PVN in regulating sympathetic outflow and blood pressure. Experiments were carried out in male adult SD rats under anesthesia. Renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP), and heart rate (HR) were recorded, and PVN microinjections were performed bilaterally. Asprosin mRNA and protein expressions were high in the PVN. The high asprosin expression in the PVN was involved in both the parvocellular and magnocellular regions according to immunohistochemical analysis. Microinjection of asprosin into the PVN produced dose-related increases in RSNA, MAP, and HR, which were abolished by superoxide scavenger tempol, antioxidant N-acetylcysteine (NAC), and NADPH oxidase inhibitor apocynin. The asprosin promoted superoxide production and increased NADPH oxidase activity in the PVN. Furthermore, it increased the cAMP level, adenylyl cyclase (AC) activity, and protein kinase A (PKA) activity in the PVN. The roles of asprosin in increasing RSNA, MAP, and HR were prevented by pretreatment with AC inhibitor SQ22536 or PKA inhibitor H89 in the PVN. Microinjection of cAMP analog db-cAMP into the PVN played similar roles with asprosin in increasing the RSNA, MAP, and HR, but failed to further augment the effects of asprosin. Pretreatment with PVN microinjection of SQ22536 or H89 abolished the roles of asprosin in increasing superoxide production and NADPH oxidase activity in the PVN. These results indicated that asprosin in the PVN increased the sympathetic outflow, blood pressure, and heart rate via cAMP-PKA signaling-mediated NADPH oxidase activation and the subsequent superoxide production.

Chronic Infusion of Astaxanthin Into Hypothalamic Paraventricular Nucleus Modulates Cytokines and Attenuates the Renin-Angiotensin System in Spontaneously Hypertensive Rats.

ABSTRACT: Oxidative stress, the renin-angiotensin system (RAS), and inflammation are some of the mechanisms involved in the pathogenesis of hypertension. The aim of this study is to examine the protective effect of the chronic administration of astaxanthin, which is extracted from the shell of crabs and shrimps, into hypothalamic paraventricular nucleus (PVN) in spontaneously hypertensive rats. Animals were randomly assigned to 2 groups and treated with bilateral PVN infusion of astaxanthin or vehicle (artificial cerebrospinal fluid) through osmotic minipumps (Alzet Osmotic Pumps, Model 2004, 0.25 µL/h) for 4 weeks. Spontaneously hypertensive rats had higher mean arterial pressure and plasma level of norepinephrine and proinflammatory cytokine; higher PVN levels of reactive oxygen species, NOX2, NOX4, IL-1ß, IL-6, ACE, and AT1-R; and lower PVN levels of IL-10 and Cu/Zn SOD, Mn SOD, ACE2, and Mas receptors than Wistar-Kyoto rats. Our data showed that chronic administration of astaxanthin into PVN attenuated the overexpression of reactive oxygen species, NOX2, NOX4, inflammatory cytokines, and components of RAS within the PVN and suppressed hypertension. The present results revealed that astaxanthin played a role in the brain. Our findings demonstrated that astaxanthin had protective effect on hypertension by improving the balance between inflammatory cytokines and components of RAS.

Inhibition of miR-135a-5p attenuates vascular smooth muscle cell proliferation and vascular remodeling in hypertensive rats.

Proliferation of vascular smooth muscle cells (VSMCs) greatly contributes to vascular remodeling in hypertension. This study is to determine the roles and mechanisms of miR-135a-5p intervention in attenuating VSMC proliferation and vascular remodeling in spontaneously hypertensive rats (SHRs). MiR-135a-5p level was raised, while fibronectin type III domain-containing 5 (FNDC5) mRNA and protein expressions were reduced in VSMCs of SHRs compared with those of Wistar-Kyoto rats (WKYs). Enhanced VSMC proliferation in SHRs was inhibited by miR-135a-5p knockdown or miR-135a-5p inhibitor, but exacerbated by miR-135a-5p mimic. VSMCs of SHRs showed reduced myofilaments, increased or even damaged mitochondria, increased and dilated endoplasmic reticulum, which were attenuated by miR-135a-5p inhibitor. Dual-luciferase reporter assay shows that FNDC5 was a target gene of miR-135a-5p. Knockdown or inhibition of miR-135a-5p prevented the FNDC5 downregulation in VSMCs of SHRs, while miR-135a-5p mimic inhibited FNDC5 expressions in VSMCs of both WKYs and SHRs. FNDC5 knockdown had no significant effects on VSMC proliferation of WKYs, but aggravated VSMC proliferation of SHRs. Exogenous FNDC5 or FNDC5 overexpression attenuated VSMC proliferation of SHRs, and prevented miR-135a-5p mimic-induced enhancement of VSMC proliferation of SHR. MiR-135a-5p knockdown in SHRs attenuated hypertension, normalized FNDC5 expressions and inhibited vascular smooth muscle proliferation, and alleviated vascular remodeling. These results indicate that miR-135a-5p promotes while FNDC5 inhibits VSMC proliferation in SHRs. Silencing of miR-135a-5p attenuates VSMC proliferation and vascular remodeling in SHRs via disinhibition of FNDC5 transcription. Either inhibition of miR-135a-5p or upregulation of FNDC5 may be a therapeutically strategy in attenuating vascular remodeling and hypertension.

The Anatomical and Biomechanical Superiority of Novel Posterior En Bloc Elevation Cervical Laminoplasty.

Objectives. In this study, we performed a novel type of posterior en bloc elevation cervical laminoplasty (PEEL) to keep the integrity of the posterior structure, aiming to reduce axial symptoms complicated by a conventional cervical laminoplasty procedure. Methods. Twelve human cervical cadaveric spines (C2-T1) were sequentially tested in the following order: intact condition, open-door laminoplasty (ODL) through bilateral intermuscular approach (mini-invasive ODL), PEEL, and laminectomy (LN). After bilateral transecting at the junction of lamina and lateral mass through the tubular retraction system, the PEEL procedure symmetrically elevated all the posterior structure which was further stabilized with bone grafts and titanium plates. Computed tomography (CT) scan and biomechanical testing were performed after each condition. Results. Both mini-invasive ODL and PEEL procedures were accomplished with 2 small incisions on each side. Two types of laminoplasties could enlarge the spinal canal significantly both in cross-sectional area and anteroposterior diameter comparing with intact condition. The PEEL procedure demonstrated a significantly higher enlargement rate on a canal area and a symmetrical expansion pattern. Compared with intact condition, mini-invasive ODL performed from C3-C7 demonstrated significantly decreased motion in all testing directions except the flexion range of motion (ROM); the PEEL procedure showed mild and insignificant decrease on ROM in all directions. Laminectomy resulted in a statistically significant increase in all directions except the lateral bending ROM. Conclusions. Posterior en bloc elevation cervical laminoplasty can enlarge the canal more effectively and preserve better ROM after operation than the ODL procedure. Although technically challenging, the PEEL procedure probably would decrease the common complications associated with ODL laminoplasty.

Interleukin-1ß in hypothalamic paraventricular nucleus mediates excitatory renal reflex.

Chemical stimulation of kidney causes sympathetic activation and pressor responses in rats. The excitatory renal reflex (ERR) is mediated by angiotensin type 1 receptor (AT1R) and superoxide anions in hypothalamic paraventricular nucleus (PVN). The aim of this study is to determine whether interleukin-1ß (IL-1ß) in the PVN mediates the ERR, and whether the IL-1ß production in the PVN is dependent on the AT1R-superoxide anion signaling. Experiments were performed in adult rats under anesthesia. The ERR was induced by renal infusion of capsaicin, and evaluated by the responses of the contralateral renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP). Inhibition of IL-1ß production with MCC950 in the PVN dose-dependently inhibited the capsaicin-induced ERR and sympathetic activation. The PVN microinjection of IL-1 receptor antagonist IL-1Ra or specific IL-1ß antibody abolished the capsaicin-induced ERR, while IL-1ß enhanced the ERR. Renal infusion of capsaicin promoted p65-NFκB phosphorylation and IL-1ß production in the PVN, which were prevented by PVN microinjection of NADPH oxidase inhibitor apocynin or the superoxide anion scavenger tempol. The PVN microinjection of NFκB inhibitor BMS-345541 abolished the capsaicin induced-ERR and IL-1ß production, but not the NADPH oxidase activation and superoxide anion production. Furthermore, capsaicin-induced p65-NFκB phosphorylation and IL-1ß production in the PVN were prevented by AT1R antagonist losartan, or angiotensin converting enzyme inhibitor captopril. These results indicate that capsaicin-induced ERR and sympathetic activation are mediated by IL-1ß in the PVN. The IL-1ß production in the PVN is dependent on the AT1R-mediated superoxide anion generation and NFκB activation.

Calcitriol ameliorated autonomic dysfunction and hypertension by down-regulating inflammation and oxidative stress in the paraventricular nucleus of SHR.

The hypothalamic paraventricular nucleus (PVN) plays crucial roles in central cardiovascular regulation. Increasing evidence in humans and rodents shows that vitamin D intake is important for achieving optimal cardiovascular function. The purpose of this study was to investigate whether calcitriol, an active form of vitamin D, improves autonomic and cardiovascular function in hypertensive rats and whether PVN oxidative stress and inflammation are involved in these beneficial effects. Male spontaneously hypertensive rats (SHR) and normotensive control Wistar Kyoto (WKY) rats were treated with either calcitriol (40 ng/day) or vehicle (0.11 µL/h) through chronic PVN infusion for 4 weeks. Blood pressure and heart rate were recorded continuously by radiotelemetry. PVN tissue, heart and plasma were collected for molecular and histological analysis. Compared to WKY rats, SHR exhibited increased systolic blood pressure, sympathetic drive, and cardiac hypertrophy and remodeling. These were associated with higher mRNA and protein expression levels of high mobility box 1 (HMGB1), receptor for advanced glycation end products (RAGE), toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), proinflammatory cytokines, NADPH oxidase subunit in the PVN. In addition, increased norepinephrine in plasma, elevated reactive oxygen species levels and activation of microglia in the PVN were also observed in SHR. Chronic calcitriol treatment ameliorated these changes but not in WKY rats. Our results demonstrate that chronic infusion of calcitriol in the PVN ameliorates hypertensive responses, sympathoexcitation and retains cardiovascular function in SHR. Reduced inflammation and oxidative stress within the PVN are involved in these calcitriol-induced effects.

Irisin lowers blood pressure by activating the Nrf2 signaling pathway in the hypothalamic paraventricular nucleus of spontaneously hypertensive rats.

Exercise training is one of the major non-pharmacological treatments for hypertension. However, the central mechanism by which exercise training attenuates the hypertensive responses remains unclear. Irisin is a muscle-secreted cytokine derived from fibronectin type III domain containing 5 (FNDC5) that will be released into the circulation during exercise. We hypothesized that irisin may play a role in the blood pressure regulation by exercise. To examine the hypothesis, our study investigated the effect of irisin on hypertension and its central mechanism. The study was performed in spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto rats. We found that intravenous injection of irisin effectively reduced blood pressure, plasma norepinephrine, paraventricular nucleus (PVN) levels of neuronal activation, oxidative stress and inflammation in SHRs. Moreover, irisin activated nuclear factor E2-related factor-2 (Nrf2) and restored the imbalance of neurotransmitters in the PVN. Our study also found PVN knockdown of Nrf2 abolished the protective effects of irisin on hypertension. These findings demonstrate irisin can improve hypertension via Nrf2-mediated antioxidant in the PVN.

Inhibition of Hypothalamic Inhibitor κB Kinase ß/Nuclear Transcription Factor κB Pathway Attenuates Metabolism and Cardiac Dysfunction in Type 2 Diabetic Rats.

BACKGROUND: Inflammation and oxidative stress play important roles in energy imbalance and its complications. Recent research indicates that hypothalamic inflammation may contribute to the pathogenesis of metabolic syndrome and cardiac dysfunction, but the mechanisms remain unclear. We hypothesized that suppression of the proinflammatory IKKß/NF-κB pathway in the hypothalamus can improve energy balance and cardiac function in type 2 diabetic (T2D) rats. METHODS: Normal and T2D rats received bilateral hypothalamic arcuate nucleus (ARC) infusions of the IKKß inhibitor SC-514 or vehicle via osmotic minipump. Metabolic phenotyping, immunohistochemical analyses, and biochemical analyses were used to investigate the outcomes of inhibition of the hypothalamic IKKß. Echocardiography and glucometer were used for measuring cardiac function and blood glucose, respectively. Blood samples were collected for the evaluation of circulating proinflammatory cytokines. Heart was harvested for cardiac morphology evaluations. The ARC was harvested and analyzed for IKKß, NF-κB, proinflammatory cytokines, reactive oxygen species (ROS), and NAD(P)H (gp91phox, p47phox) oxidase activity levels and neuropeptides. RESULTS: Compared with normal rats, T2D rats were characterized by hyperglycemia, hyperinsulinemia, glucose intolerance, cardiac dysfunction, as well as higher ARC levels of IKKß, NF-κB, proinflammatory cytokines, ROS, gp91phox, and p47phox. ARC infusion of the IKKß inhibitor SC-514 attenuated all these changes in T2D rats, but not in normal rats. CONCLUSIONS: Our results indicate that the hypothalamic IKKß/NF-κB pathway plays a key role in modulating energy imbalance and cardiac dysfunction, suggesting its potential therapeutic role during type 2 diabetes mellitus.

Adipose afferent reflex is enhanced by TNFα in paraventricular nucleus through NADPH oxidase-dependent ROS generation in obesity-related hypertensive rats.

BACKGROUND: The adipose afferent reflex (AAR), a sympatho-excitatory reflex, can promote the elevation of sympathetic nerve activity (SNA) and blood pressure (BP). Inflammation in the paraventricular nucleus (PVN) involves sympathetic abnormality in some cardiovascular diseases such as hypertension. This study was designed to explore the effects of tumor necrosis factor alpha (TNFα) in the PVN on the AAR and SNA in rats with obesity-related hypertension (OH) induced by a high-fat diet for 12 weeks. METHODS: Renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were continuously recorded in anesthetized rats, and their responses to capsaicin (CAP) stimulation of the right inguinal white adipose tissue were used to evaluate the AAR. RESULTS: Compared to the control rats, the systolic blood pressure (SBP), plasma norepinephrine (NE, indicating SNA) and TNFα levels, TNFα mRNA and protein levels, reactive oxygen species (ROS) content and NADPH oxidase activity in the PVN were significantly elevated in rats with OH. TNFα in the PVN markedly enhanced sympathoexcitation and AAR. Moreover, the enhancement of AAR caused by TNFα can be significantly strengthened by the pretreatment of diethyldithiocarbamate (DETC), a superoxide dismutase inhibitor, but attenuated by TNF-α receptor antagonist R-7050, superoxide scavenger PEG-SOD and NADPH oxidase inhibitor apocynin (Apo) in rats with OH. Acute microinjection of TNF-α into the PVN significantly increased the activity of NADPH oxidase and ROS levels in rats with OH, which were effectively blocked by R-7050. Furthermore, our results also showed that the increased levels of ROS, TNFα and NADPH oxidase subunits mRNA and protein in the PVN of rats with OH were significantly reversed by pentoxifylline (PTX, 30 mg/kg daily ip; in 10% ethanol) application, a cytokine blocker, for a period of 5 weeks. PTX administration also significantly decreased SBP, AAR and plasma NE levels in rats with OH. CONCLUSIONS: TNFα in the PVN modulates AAR and contributes to sympathoexcitation in OH possibly through NADPH oxidase-dependent ROS generation. TNFα blockade attenuates AAR and sympathoexcitation that unveils TNFα in the PVN may be a possible therapeutic target for the intervention of OH.

Modulation of Plant Salicylic Acid-Associated Immune Responses via Glycosylation of Dihydroxybenzoic Acids.

Salicylic acid (SA) plays a crucial role in plant innate immunity. The deployment of SA-associated immune responses is primarily affected by SA concentration, which is determined by a balance between SA biosynthesis and catabolism. However, the mechanisms regulating SA homeostasis are poorly understood. In this study, we characterized a unique UDP-glycosyltransferase, UGT76D1, which plays an important role in SA homeostasis and associated immune responses in Arabidopsis (Arabidopsis thaliana). Expression of UGT76D1 was induced by treatment with both the pathogen Pseudomonas syringae pv. tomato (Pst) DC3000 and SA. Overexpression of UGT76D1 resulted in high SA accumulation, significant up-regulation of pathogen-related genes, and a hypersensitive response (HR)-like lesion mimic phenotype. This HR-like phenotype was not observed following UGT76D1 overexpression in SA-deficient NahG transgenic or sid2 plants, suggesting that the phenotype is SA dependent. Biochemical assays showed that UGT76D1 glycosylated 2,3-dihydroxybenzoic acid (2,3-DHBA) and 2,5-dihydroxybenzoic acid (2,5-DHBA), the major catabolic forms of SA, to their Glc and Xyl conjugates in vitro and in vivo. Moreover, in a mutant background blocked in the formation of 2,3-DHBA and 2,5-DHBA, UGT76D1 overexpression did not cause a HR-like lesion mimic phenotype. Following infection with Pst DC3000, UGT76D1 knockout mutants displayed a delayed immune response, with reduced levels of DHBA glycosides and SA, and down-regulated SA synthase expression. By contrast, UGT76D1 overexpression lines showed an enhanced immune response and increased SA biosynthesis before and after pathogen infection. Thus, we propose that UGT76D1 plays an important role in SA homeostasis and plant immune responses by facilitating glycosylation of dihydroxybenzoic acids.