Discovery of Herbacetin as a Novel SGK1 Inhibitor to Alleviate Myocardial Hypertrophy.

Cardiac hypertrophy is a pivotal pathophysiological step of various cardiovascular diseases, which eventually leads to heart failure and death. Extracts of Rhodiola species (Ext.R), a class of commonly used medicinal herbs in Europe and East Asia, can attenuate cardiac hypertrophy both in vitro and in vivo. Serum/glucocorticoid regulated kinase 1 (SGK1) is identified as a potential target of Ext. R. By mass spectrometry-based kinase inhibitory assay, herbacetin (HBT) from Ext.R is identified as a novel SGK1 inhibitor with IC50 of 752 nmol. Thermal shift assay, KINOMEscan in vitro assay combined with molecular docking proves a direct binding between HBT and SGK1. Site-specific mutation of Asp177 in SGK1 completely ablates the inhibitory activity of HBT. The presence of OH groups at the C-3, C-8, C-4' positions of flavonoids is suggested to be favorable for the inhibition of SGK1 activity. Finally, HBT significantly suppresses cardiomyocyte hypertrophy in vitro and in vivo, reduces reactive oxygen species (ROS) synthesis and calcium accumulation. HBT decreases phosphorylation of SGK1 and regulates its downstream forkhead box protein O1 (FoxO1) signaling pathway. Taken together, the findings suggest that a panel of flavonoids structurally related to HBT may be novel leads for developing new therapeutics against cardiac hypertrophy.

Growth hormone promotes hepatic gluconeogenesis by enhancing BTG2-YY1 signaling pathway.

Growth hormone (GH) is one of the critical factors in maintaining glucose metabolism. B-cell translocation gene 2 (BTG2) and yin yang 1 (YY1) are key regulators of diverse metabolic processes. In this study, we investigated the link between GH and BTG2-YY1 signaling pathway in glucose metabolism. GH treatment elevated the expression of hepatic Btg2 and Yy1 in primary mouse hepatocytes and mouse livers. Glucose production in primary mouse hepatocytes and serum blood glucose levels were increased during GH exposure. Overexpression of hepatic Btg2 and Yy1 induced key gluconeogenic enzymes phosphoenolpyruvate carboxykinase 1 (PCK1) and glucose-6 phosphatase (G6PC) as well as glucose production in primary mouse hepatocytes, whereas this phenomenon was markedly diminished by knockdown of Btg2 and Yy1. Here, we identified the YY1-binding site on the Pck1 and G6pc gene promoters using reporter assays and point mutation analysis. The regulation of hepatic gluconeogenic genes induced by GH treatment was clearly linked with YY1 recruitment on gluconeogenic gene promoters. Overall, this study demonstrates that BTG2 and YY1 are novel regulators of GH-dependent regulation of hepatic gluconeogenic genes and glucose production. BTG2 and YY1 may be crucial therapeutic targets to intervene in metabolic dysfunction in response to the GH-dependent signaling pathway.

Treatment for liver cancer: From sorafenib to natural products.

Liver cancer most commonly develops in patients with chronic liver disease, the etiology of which includes viral hepatitis (B and C), alcohol, obesity, dietary carcinogens, and so forth. The current treatment modalities, including surgical resection and liver transplantation, have been found far from effective. Hence, there is an obvious critical need to develop alternative strategies for the treatment of it. In this review, we discuss the formation process and therapeutic targets of liver cancer. Currently, targeted therapy is limited to sorafenib, lenvatinib, regorafenib, ramucirumab and cabozantinib which leads to a survival benefit in patients, but on the other hand is hampered by the occurrence of drug resistance. Pleasingly and importantly, there are multiple natural products undergoing clinical evaluation in liver cancer, such as polyphenols like icaritin, resveratrol, and silybin, saponins including ginsenoside Rg3 and glycyrrhizinate, alkaloid containing irinotecan and berberine and inorganic compound arsenic trioxide at present. Preclinical and clinical studies have shown that these compounds inhibit liver cancer formation owing to the influence on the anti-viral, anti-inflammation, anti-oxidant, anti-angiogenesis and anti-metastasis activity. Furthermore, a series of small molecule derivatives inspired by the aforementioned compounds are designed and synthesized according to structure-activity relationship studies. Drug combination and novel type of drug-targeted delivery system thereof have been well developed. This article is ended by a perspective remark of futuristic development of natural product-based therapeutic regimen for liver cancer treatment. We expect that this review is an account for current status of natural products as promising anti-liver cancer treatments and should contribute to its understanding.

Suppression of phosphoinositide 3-kinase/phosphoinositide-dependent kinase-1/serum and glucocorticoid-induced protein kinase pathway.

In the current study, the pivotal roles of serum and glucocorticoid-induced protein kinase (SGK1) and NF-kB related signalings known as prognostic biomarkers in cervical cancers were explored in the antitumor effect of a ginseng saponin metabolite compound K (CK) in HeLa and SiHa cervical cancer cells. CK exerted significant cytotoxicity, induced sub-G1 accumulation, and attenuated the expression of proPoly (ADP-ribose) polymerase (pro-PARP) and Pro-cysteine aspartyl-specific protease (pro-caspase3) in HeLa cells more than in SiHa cells. CK inhibited phosphorylation of SGK1 and its upstream genes, phosphoinositide 3-kinases (PI3K), and phosphoinositide-dependent kinase-1 (PDK1) in HeLa cells. In addition, CK suppressed the phosphorylation of SGK1, NF-κB, and inhibitor of kappa B (IκB) and also NF-κB target genes such as X-linked inhibitor of apoptosis protein and B-cell lymphoma 2 (Bcl-2) in HeLa cells. Notably, Immunoprecipitation revealed that SGK1 binds to PI3K or PDK1 and also CK disturbed the binding between SGK1 and PI3K or PDK1 in HeLa cells. Furthermore, PI3K inhibitor LY294002 decreased expression of PI3K, p-PDK1, p-SGK1, and pro-caspase3 and SGK1 inhibitor GSK650394 also reduced expression of NF-κB and pro-caspase3 just like CK in HeLa cells. Overall, these findings suggest that CK induces apoptosis via suppression of PI3K/PDK1/SGK1 and NF-κB signaling axis.

Regulation of Rhcg, an ammonia transporter, by aldosterone in the kidney.

Rhesus C glycoprotein (Rhcg), an ammonia transporter, is a key molecule in urinary acid excretion and is expressed mainly in the intercalated cells (ICs) of the renal collecting duct. In the present study we investigated the role of aldosterone in the regulation of Rhcg expression. In in vivo experiments using C57BL/6J mice, Western blot analysis showed that continuous subcutaneous administration of aldosterone increased the expression of Rhcg in membrane fraction of the kidney. Supplementation of potassium inhibited the effect of aldosterone on the Rhcg. Next, mice were subjected to adrenalectomy with or without administration of aldosterone, and then ad libitum 0.14 M NH4Cl containing water was given. NH4Cl load increased the expression of Rhcg in membrane fraction. Adrenalectomy decreased NH4Cl-induced Rhcg expression, which was restored by administration of aldosterone. Immunohistochemical studies revealed that NH4Cl load induced the localization of Rhcg at the apical membrane of ICs in the outer medullary collecting duct. Adrenalectomy decreased NH4Cl-induced membrane localization of Rhcg, which was restored by administration of aldosterone. For in vitro experiments, IN-IC cells, an immortalized cell line stably expressing Flag-tagged Rhcg (Rhcg-Flag), were used. Western blot analysis showed that aldosterone increased the expression of Rhcg-Flag in membrane fraction, while the increase in extracellular potassium level inhibited the effect of aldosterone. Both spironolactone and GÓ§6983, a PKC inhibitor, inhibited the expression of Rhcg-Flag in the membrane fraction. These results suggest that aldosterone regulates the membrane expression of Rhcg through the mineralocorticoid receptor and PKC pathways, which is modulated by extracellular potassium level.

Vasopressin-stimulated ORAI1 expression and store-operated Ca2+ entry in aortic smooth muscle cells.

Vascular calcification may result from stimulation of osteogenic signalling with upregulation of the transcription factors CBFA1, MSX2 and SOX9, as well as alkaline phosphatase (ALPL), which degrades and thus inactivates the calcification inhibitor pyrophosphate. Osteogenic signalling further involves upregulation of the Ca2+-channel ORAI1. The channel is activated by STIM1 and then accomplishes store-operated Ca2+ entry. ORAI1 and STIM1 are upregulated by the serum & glucocorticoid inducible kinase 1 (SGK1) which is critically important for osteogenic signalling. Stimulators of vascular calcification include vasopressin. The present study explored whether exposure of human aortic smooth muscle cells (HAoSMCs) to vasopressin upregulates ORAI1 and/or STIM1 expression, store-operated Ca2+ entry and osteogenic signalling. To this end, HAoSMCs were exposed to vasopressin (100 nM, 24 h) without or with additional exposure to ORAI1 blocker MRS1845 (10 µM) or SGK1 inhibitor GSK-650394 (1 µM). Transcript levels were measured using q-RT-PCR, cytosolic Ca2+-concentration ([Ca2+]i) by Fura-2-fluorescence, and store-operated Ca2+ entry from increase of [Ca2+]i following re-addition of extracellular Ca2+ after store depletion with thapsigargin (1 µM). As a result, vasopressin enhanced the transcript levels of ORAI1 and STIM1, store-operated Ca2+ entry, as well as the transcript levels of CBFA1, MSX2, SOX9 and ALPL. The effect of vasopressin on store-operated Ca2+ entry as well as on transcript levels of CBFA1, MSX2, SOX9 and ALPL was virtually abrogated by MRS1845 and GSK-650394. In conclusion, vasopressin stimulates expression of ORAI1/STIM1, thus augmenting store-operated Ca2+ entry and osteogenic signalling. In HAoSMCs, vasopressin (VP) upregulates Ca2+ channel ORAI1 and its activator STIM1. VP upregulates store-operated Ca2+ entry (SOCE) and osteogenic signalling (OS). VP-induced SOCE, OS and Ca2+-deposition are disrupted by ORAI1 inhibitor MRS1845. VP-induced SOCE, OS and Ca2+-deposition are disrupted by SGK1 blocker GSK-650394. KEY MESSAGES: • In HAoSMCs, vasopressin (VP) upregulates Ca2+ channel ORAI1 and its activator STIM1. • VP upregulates store-operated Ca2+ entry (SOCE) and osteogenic signalling (OS). • VP-induced SOCE, OS and Ca2+-deposition are disrupted by ORAI1 inhibitor MRS1845. • VP-induced SOCE, OS and Ca2+-deposition are disrupted by SGK1 blocker GSK-650394.

Acid sphingomyelinase promotes SGK1-dependent vascular calcification.

In chronic kidney disease (CKD), hyperphosphatemia is a key factor promoting medial vascular calcification, a common complication associated with cardiovascular events and high mortality. Vascular calcification involves osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells (VSMCs), but the complex signaling events inducing pro-calcific pathways are incompletely understood. The present study investigated the role of acid sphingomyelinase (ASM)/ceramide as regulator of VSMC calcification. In vitro, both, bacterial sphingomyelinase and phosphate increased ceramide levels in VSMCs. Bacterial sphingomyelinase as well as ceramide supplementation stimulated osteo-/chondrogenic transdifferentiation during control and high phosphate conditions and augmented phosphate-induced calcification of VSMCs. Silencing of serum- and glucocorticoid-inducible kinase 1 (SGK1) blunted the pro-calcific effects of bacterial sphingomyelinase or ceramide. Asm deficiency blunted vascular calcification in a cholecalciferol-overload mouse model and ex vivo isolated-perfused arteries. In addition, Asm deficiency suppressed phosphate-induced osteo-/chondrogenic signaling and calcification of cultured VSMCs. Treatment with the functional ASM inhibitors amitriptyline or fendiline strongly blunted pro-calcific signaling pathways in vitro and in vivo. In conclusion, ASM/ceramide is a critical upstream regulator of vascular calcification, at least partly, through SGK1-dependent signaling. Thus, ASM inhibition by repurposing functional ASM inhibitors to reduce the progression of vascular calcification during CKD warrants further study.

A G-quadruplex nanoswitch in the SGK1 promoter regulates isoform expression by K+/Na+ balance and resveratrol binding.

BACKGROUND: High sodium intake can up-regulate the level of renal serum- and glucocorticoid-inducible kinase-1 (SGK1), which plays a pivotal role in controlling blood pressure via activation of the epithelial sodium channel (ENaC), which can lead to salt-sensitive hypertension. Increased potassium intake, or a vegetarian diet, counteracts salt-sensitive hypertension, but the underlying mechanisms are not fully understood. METHODS: Bioinformatics and molecular modeling were used to identify G-quadruplex (G4) and their conformations in the SGK1 promoter. CD spectra and UV melting dynamics were measured to study the stability of G4 as influenced by potassium/sodium balance and resveratrol. RT-PCR and Western blot were employed to study the effects of potassium and resveratrol on the SGK1 isoform expression. RESULTS: The SGK1 gene encodes a G4 structure in the proximal upstream of promoter-2; the G4 structure is stabilized by potassium or resveratrol, but destabilized by sodium. Super-physiological levels of sodium stimulate the transcription of all SGK1 isoforms, whereas resveratrol or potassium supplementation inhibits the transcription of iso-2 and iso-3, but not iso-1. CONCLUSIONS: Stabilizing the G4 by potassium or resveratrol induces alternative promoter usage and/or pre-mRNA splicing in the transcription of SGK1. GENERAL SIGNIFICANCE: Potassium/sodium ion balance or resveratrol binding can act to regulate G4 molecular switches for controlling SGK1 gene expression, thereby presenting a new avenue for drug development.

Glucocorticoids Reverse Diluted Hyponatremia Through Inhibiting Arginine Vasopressin Pathway in Heart Failure Rats.

Background Arginine vasopressin dependent antidiuresis plays a key role in water-sodium retention in heart failure. In recent years, the role of glucocorticoids in the control of body fluid homeostasis has been extensively investigated. Glucocorticoid deficiency can activate V2R (vasopressin receptor 2), increase aquaporins expression, and result in hyponatremia, all of which can be reversed by glucocorticoid supplement. Methods and Results Heart failure was induced by coronary artery ligation for 8 weeks. A total of 32 rats were randomly assigned to 4 groups (n=8/group): sham surgery group, congestive heart failure group, dexamethasone group, and dexamethasone in combination with glucocorticoid receptor antagonist RU486 group. An acute water loading test was administered 6 hours after drug administration. Left ventricular function was measured by a pressure-volume catheter. Protein expressions were determined by immunohistochemistry and immunoblotting. The pressure-volume loop analysis showed that dexamethasone improves cardiac function in rats with heart failure. Western blotting confirmed that dexamethasone remarkably reduces the expressions of V2R, aquaporin 2, and aquaporin 3 in the renal-collecting ducts. As a result of V2R downregulation, the expressions of glucocorticoid regulated kinase 1, apical epithelial sodium channels, and the furosemide-sensitive Na-K-2Cl cotransporter were also downregulated. These favorable effects induced by dexamethasone were mostly abolished by the glucocorticoid receptor inhibitor RU486, indicating that the aforementioned effects are glucocorticoid receptor mediated. Conclusions Glucocorticoids can reverse diluted hyponatremia via inhibiting the vasopressin receptor pathway in rats with heart failure.

Bioactive constituents of Lindernia crustacea and its anti-EBV effect via Rta expression inhibition in the viral lytic cycle.

ETHNOPHARMACOLOGICAL RELEVANCE: Lindernia crustacea (L.) F.Muell. (Scrophulariaceae) was selected for phytochemical investigation owing to its traditional use against human herpes virus infection and its anti-Epstein-Barr virus (EBV) effect. AIMS OF THE STUDY: The present study focused on the phytochemical investigation of L. crustacea including the isolation and structure determination of its biologically active compounds. Compounds with anti-EBV effects were also investigated. MATERIALS AND METHODS: The EtOH extract of L. crustacea was subsequently partitioned using different solvents. The EtOAc fraction was subjected to several chromatographic methods to obtain pure compounds. The structures of all isolates were established by spectroscopic analysis and compared with previously reported physical data. The anti-EBV effect was evaluated in an EBV-containing Burkitt's lymphoma cell line (P3HR1) to study the expression of EBV lytic proteins. RESULTS: Thirty-three compounds, including one diterpene (1), four anthraquinones (2-5), two ionones (6 and 7), fourteen phenylpropanoid glycosides (8-21), five flavonoids (22-26), one lignan glycoside (27), one phenethyl alcohol glycoside (28), one phenylpropene glycoside (29), one glucosyl glycerol derivative (30), one furanone (31), and two cinnamic acid derivatives (32 and 33), were isolated from the ethanolic extract of the plant. All isolated compounds were obtained for the first time from Lindernia sp. The evaluation of the anti-EBV activity of L. crustacea crude extract, partitioned fractions, and constituents was performed for the first time. Phytol (1), aloe-emodin (2), byzantionoside B (7), a mixture of trans-martynoside (8) and cis-martynoside (9), a mixture of trans-isomartynoside (10) and cis-isomartynoside (11), luteolin-7-O-ß-D-glucopyranoside (24), and apigenin-7-O-[ß-D-apiofuranosyl (1→6)-ß-D-glucopyranoside] (25) exhibited significant inhibitory effects on the EBV lytic cycle at 20 µg/mL in the immunoblot analysis. On the other hand, (6R,7E,9R)-3-oxo-α-ionol-ß-D-glucopyranoside (6) and a mixture of trans-dolichandroside A (12) and cis-dolichandroside A (13) showed moderate anti-EBV activity at 20 µg/mL. CONCLUSIONS: L. crustacea and its active isolates could be developed as potential candidates against EBV. Our findings provide scientific evidence for the traditional use of L. crustacea for its antiviral effects.

Jixuepaidu Tang-1 inhibits epithelial-mesenchymal transition and alleviates renal damage in DN mice through suppressing long non-coding RNA LOC498759.

Jixuepaidu Tang-1 is obtained from the decoction of the Chinese traditional medicinal plants including Centella asiatica, Astragalus membranaceus, and Sanguis draconis. Transforming growth factor-ß1 (TGF-ß1)/serum- and glucocorticoid-inducible kinase-1 (SGK1)-induced epithelial-mesenchymal transition (EMT) plays a pivotal role in the pathogenesis of diabetic nephropathy (DN). In addition, long non-coding RNAs (lnRNAs) participate in the development of DN, but the role of lncRNA LOC498759 in DN is still unclear. This study aims to investigate the role of Jixuepaidu Tang-1 in regulating podocyte injury and renal damage in DN and to validate whether the mechanisms involve TGF-ß1/SGK1 signaling and LOC498759. The drug treatment was initiated 2 weeks after the DN modeling. The MTT method and TUNEL staining were used to measure cell viability and apoptosis, respectively. Immunofluorescence staining was used to detect the expression of nephrin and desmin in podocytes. Sera from the Jixuepaidu Tang-1-treated mice reversed the high glucose (HG)-induced podocyte injury and EMT in mouse podocytes. Further in vivo assay revealed that Jixuepaidu Tang-1 not only reduced the ratio of the kidney to body weight, 24 h-urine total protein, and blood glucose, but alleviated glomerular mesangial extracellular matrix deposition and glomerular cell apoptosis in the streptozotocin-induced DN mice. Mechanically, the mechanisms of Jixuepaidu Tang-1 may involve the suppression of EMT by inhibiting the TGF-ß1/SGK1-induced LOC498759 expression. Collectively, Jixuepaidu Tang-1 attenuates podocyte injury and renal damage in DN, and inhibits EMT through suppressing TGF-ß1/SGK1-LOC498759 signaling.

Effects of the Ethanol Extract of Dipterocarpus alatus Leaf on the Unpredictable Chronic Mild Stress-Induced Depression in ICR Mice and Its Possible Mechanism of Action.

Treatment of the unpredictable chronic mild stress (UCMS) mice with the ethanol extract of Dipterocarpus alatus leaf attenuated anhedonia (increased sucrose preference) and behavioral despair (decreased immobility time in tail suspension test (TST) and forced swimming test (FST)). The extract not only decreased the elevation of serum corticosterone level and the index of over-activation of the hypothalamic-pituitary-adrenal (HPA) axis, caused by UCMS, but also ameliorated UCMS-induced up-regulation of serum- and glucocorticoid-inducible kinase 1 (SGK1) mRNA expression and down-regulation of cyclic AMP-responsive element binding (CREB) and brain-derived neurotrophic factor (BDNF) mRNAs in frontal cortex and hippocampus. In vitro monoamine oxidase (MAO) inhibition assays showed that the extract exhibited the partial selective inhibition on MAO-A. HPLC analysis of the extract showed the presence of flavonoids (luteolin-7-O-glucoside, kaempferol-3-glucoside, rutin) and phenolic acids (gallic acid, ferulic acid, and caffeic acid) as major constituents.

Honeysuckle-derived microRNA2911 directly inhibits varicella-zoster virus replication by targeting IE62 gene.

Varicella-zoster virus (VZV) leads to chicken pox on primary infection and herpes zoster on reactivation. Recent studies suggest that microRNA2911 (MIR2911), honeysuckle (HS)-encoded atypical microRNA, has potential as a therapeutic agent against influenza and EV71 virus infections. Here, we report that MIR2911 directly inhibits VZV replication by targeting the IE62 gene. The luciferase reporter assay and bioinformatics prediction revealed that MIR2911 could target the IE62 gene of VZV. The VZV-encoded IE62 protein expression was inhibited significantly by synthetic MIR2911, while the expression of the mutants, whose MIR2911-binding sites were modified, was not inhibited. The RNA extracted from HS decoction and synthetic MIR2911 considerably suppressed VZV infection. However, it did not influence viral replication of a mutant virus with alterations in the nucleotide sequences of IE62. At the same time, the RNA extracted from HS decoction treated with the anti-MIR2911 antagomir could not inhibit the VZV replication, demonstrating that VZV replication was specifically and sufficiently inhibited by MIR2911. These results indicated that, by targeting the IE62 gene, MIR2911 may effectively inhibit VZV replication. Our results also suggest a potential novel strategy for the treatment and prevention of diseases caused by VZV infection.

Qing Chang Hua Shi granule ameliorate inflammation in experimental rats and cell model of ulcerative colitis through MEK/ERK signaling pathway.

Ulcerative colitis (UC), a bowel disease with significant morbidity, is associated with inflammation. In this study, the effect of Qingchang Huashi granule (QCHS) on UC and its underlying mechanisms were explored using both animal and cell culture experiments. A rat UC model was induced with trinitro-benzene-sulfonic acid (TNBS), concentrations of the cytokines IL-1α, IL-6, IL-8, IL-1ß, and TNF-α were significantly up-regulated and the concentrations of IL-4, IL-10, and IL-13 were significantly down-regulated compared with the control group (P < 0.05). In contrast, the QCHS and salicylazosulfapyridine (SASP) groups reversed these modulations (P < 0.05). A UC cell model in HT-29 cells was generated using TNF-α combined with lipopolysaccharide treatment. Cells treated with QCHS were used to investigate the possible mechanisms. The expression of apoptosis-related proteins, including Bax/Bcl-2, caspase-3, caspase-9, Fas/Fas-L, and Rafl in the QCHS and SASP groups, were significantly lower than that in the control group in both animal and cell experiments (P < 0.05). In addition, the in vitro results indicate changes in these indicators mediate the MEK/ERK signaling pathways via SGK1. Our results suggested that QCHS could be beneficial in preventing UC progression as an alternative drug for UC treatment.

Acupuncture Inhibits the Increase in Alpha-Synuclein by Modulating SGK1 in an MPTP Induced Parkinsonism Mouse Model.

Parkinson's disease (PD), a progressive neurodegenerative disease, is caused by the loss of dopaminergic neurons in the substantia nigra (SN). It is characterized by the formation of intracytoplasmic Lewy bodies that are primarily composed of the protein alpha-synuclein ( α -syn) along with dystrophic neurites. Acupuncture stimulation results in an enhanced survival of dopaminergic neurons in the SN in parkinsonism animal models. We investigated the role of acupuncture in inhibiting the increase in α -syn expression that is related with dopaminergic cell loss in the SN in a chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) parkinsonism mouse model. In this model, acupuncture stimulation at GB34 and LR3 attenuated the decrease in tyrosine hydroxylase. Moreover, acupuncture stimulation attenuated the increase in α -syn. We identified that serum- and glucocorticoid-dependent kinase 1 (SGK1) is evidently downregulated in chronic MPTP-intoxication and acupuncture stimulation maintained SGK1 expression at levels similar to the control group. For an examination of the expression correlation between SGK1 and α -syn, SH-SY5Y cells were knocked down with SGK1 siRNA then, the downregulation of dopaminergic cells and the increase in the expression of α -syn were observed. Our findings indicate that the acupuncture-mediated inhibition in the α -syn increase induced by MPTP may be responsible for modulating SGK1 expression.

SGK1/FOXO3 Signaling in Hypothalamic POMC Neurons Mediates Glucocorticoid-Increased Adiposity.

Although the central nervous system has been implicated in glucocorticoid-induced gain of fat mass, the underlying mechanisms are poorly understood. The aim of this study was to investigate the possible involvement of hypothalamic serum- and glucocorticoid-regulated kinase 1 (SGK1) in glucocorticoid-increased adiposity. It is well known that SGK1 expression is induced by acute glucocorticoid treatment, but it is interesting that we found its expression to be decreased in the arcuate nucleus of the hypothalamus, including proopiomelanocortin (POMC) neurons, following chronic dexamethasone (Dex) treatment. To study the role of SGK1 in POMC neurons, we produced mice that developed or experienced adult-onset SGK1 deletion in POMC neurons (PSKO). As observed in Dex-treated mice, PSKO mice exhibited increased adiposity and decreased energy expenditure. Mice overexpressing constitutively active SGK1 in POMC neurons consistently had the opposite phenotype and did not experience Dex-increased adiposity. Finally, Dex decreased hypothalamic α-melanocyte-stimulating hormone (α-MSH) content and its precursor Pomc expression via SGK1/FOXO3 signaling, and intracerebroventricular injection of α-MSH or adenovirus-mediated FOXO3 knockdown in the arcuate nucleus largely reversed the metabolic alterations in PSKO mice. These results demonstrate that POMC SGK1/FOXO3 signaling mediates glucocorticoid-increased adiposity, providing new insights into the mechanistic link between glucocorticoids and fat accumulation and important hints for possible treatment targets for obesity.

Zinc chloride rapidly stimulates efflux transporters in renal proximal tubules of killifish (Fundulus heteroclitus).

Multidrug resistance-related protein 2 (Mrp2) is an ATP-driven efflux pump at the luminal membrane in renal proximal tubules. It acts as detoxification mechanism by transporting xenobiotics and metabolic products into urine. The trace element zinc is essential for cellular growth, differentiation and survival. It modulates immune response and is used as dietary supplement. Here, we found that 0.1-10µM ZnCl2 rapidly stimulated transport of the Mrp2 probe substrate Texas Red (TR) in isolated killifish renal proximal tubules, which provide an established model system to measure efflux transporter activity by using fluorescent probe substrates, confocal microscopy and image analysis. This stimulation was insensitive to the translation inhibitor cycloheximide (CHX), but it was quickly reversed by removing ZnCl2 from the incubation medium. ZnCl2-induced transport stimulation was abolished by inhibitors and antagonists of the endothelin receptor type B (ETB)/nitric oxide synthase (NOS)/protein kinase C (PKC) pathway. Moreover, ZnCl2-induced effects were blocked by inhibition of PKCα using Gö6976 and PKCα inhibitor peptide C2-4. Both the phosphatidylinositol 3-kinase (PI3K) inhibitor LY 294002 and the mammalian target of rapamycin (mTOR) inhibitor rapamycin abolished ZnCl2-induced transport stimulation. Furthermore, the stimulating effects of ZnCl2 were blocked by GSK650394, an inhibitor of the downstream target serum- and glucocorticoid-inducible kinase 1 (SGK1). ZnCl2 also stimulated transport mediated by P-glycoprotein (P-gp) and Breast cancer resistance protein (Bcrp). This is the first report about zinc affecting efflux transporter activity and demonstrates that ZnCl2 triggers a suite of signaling events to evoke a rapid stimulation of ABC transporter-mediated efflux in killifish proximal tubules.

1,2,3,4,6-Penta-O-galloyl-ß-D-glucose, a bioactive compound in Elaeocarpus sylvestris extract, inhibits varicella-zoster virus replication.

The aim of this study was to establish the effect of a 70% ethanol extract of Elaeocarpus sylvestris (ESE) on varicella-zoster virus (VZV) replication and identify the specific bioactive component(s) underlying its activity. ESE induced a significant reduction in replication of the clinical strain of VZV. Activity-guided fractionation indicated that the ethyl acetate (EtOAc) fraction of ESE contains the active compound(s) inhibiting VZV replication. High-Performance Liquid Chromatography coupled to Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry (HPLC-Q-TOF-MS/MS) analysis of the EtOAc fraction of ESE facilitated the identification of 13 chemical components. Among these, 1,2,3,4,6-penta-O-galloyl-ß-D-glucose (PGG) markedly suppressed VZV-induced c-Jun N-terminal kinase (JNK) activation, expression of viral immediate-early 62 (IE62) protein and VZV replication. Our results collectively support the utility of PGG as a potential candidate anti-viral drug to treat VZV-associated diseases.

Proanthocyanidins block aldosterone-dependent up-regulation of cardiac gamma ENaC and Nedd4-2 inactivation via SGK1.

Aldosterone plays a central role in the development of cardiac pathological states involving ion transport imbalances, especially sodium transport. We have previously demonstrated a cardioprotective effect of proanthocyanidins in aldosterone-treated rats. Our objective was to investigate for the first time the effect of proanthocyanidins on serum and glucocorticoid-regulated kinase 1 (SGK1), epithelial Na+ channel (γ-ENaC), neuronal precursor cells expressed developmentally down-regulated 4-2 (Nedd4-2) and phosphoNedd4-2 protein expression in the hearts of aldosterone-treated rats. Male Wistar rats received aldosterone (1mg kg-1day-1)+1% NaCl for 3weeks. Half of the animals in each group were simultaneously treated with the proanthocyanidins-rich extract (80% w/w) (PRO80, 5mg kg-1day-1). Hypertension and diastolic dysfunction induced by aldosterone were abolished by treatment with PRO80. Expression of fibrotic, inflammatory and oxidative mediators were increased by aldosterone-salt administration and blunted by PRO80. Antioxidant capacity was improved by PRO80. The up-regulated aldosterone mediator SGK1, ENaC and p-Nedd4-2/total Nedd4-2 ratio were blocked by PRO80. PRO80 blunted aldosterone-mineralocorticoid-mediated up-regulation of ENaC provides new mechanistic insight of the beneficial effect of proanthocyanidins preventing the cardiac alterations induced by aldosterone excess.

Mirrored patterns of lateralized neuronal activation reflect old and new memories in the avian auditory cortex.

In monolingual humans, language-related brain activation shows a distinct lateralized pattern, in which the left hemisphere is often dominant. Studies are not as conclusive regarding the localization of the underlying neural substrate for language in sequential language learners. Lateralization of the neural substrate for first and second language depends on a number of factors including proficiency and early experience with each language. Similar to humans learning speech, songbirds learn their vocalizations from a conspecific tutor early in development. Here, we show mirrored patterns of lateralization in the avian analog of the mammalian auditory cortex (the caudomedial nidopallium [NCM]) in sequentially tutored zebra finches (Taeniopygia guttata​) in response to their first tutor song, learned early in development, and their second tutor song, learned later in development. The greater the retention of song from their first tutor, the more right-dominant the birds were when exposed to that song; the more birds learned from their second tutor, the more left-dominant they were when exposed to that song. Thus, the avian auditory cortex may preserve lateralized neuronal traces of old and new tutor song memories, which are dependent on proficiency of song learning. There is striking resemblance in humans: early-formed language representations are maintained in the brain even if exposure to that language is discontinued. The switching of hemispheric dominance related to the acquisition of early auditory memories and subsequent encoding of more recent memories may be an evolutionary adaptation in vocal learners necessary for the behavioral flexibility to acquire novel vocalizations, such as a second language.