scholarly journals Melanocortins induce interleukin 6 gene expression and secretion through melanocortin receptors 2 and 5 in 3T3-L1 adipocytes

2010 ◽  
Vol 44 (4) ◽  
pp. 225-236 ◽  
Author(s):  
Dong-Jae Jun ◽  
Kyung-Yoon Na ◽  
Wanil Kim ◽  
Dongoh Kwak ◽  
Eun-Jeong Kwon ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Interleukin 6 ◽  
Membrane Receptors ◽  
Mitogen Activated Protein Kinase ◽  
Melanocortin Receptors ◽  
Intracellular Camp ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Iκb Kinase

Interleukin 6 (IL6) is a pleiotropic cytokine that not only affects the immune system, but also plays an active role in many physiological events in various organs. Notably, 35% of systemic IL6 originates from adipose tissues under noninflammatory conditions. Here, we describe a previously unknown function of melanocortins in regulating Il6 gene expression and production in 3T3-L1 adipocytes through membrane receptors which are called melanocortin receptors (MCRs). Of the five MCRs that have been cloned, MC2R and MC5R are expressed during adipocyte differentiation. α-Melanocyte-stimulating hormone (α-MSH) or ACTH treatment of 3T3-L1 adipocytes induces Il6 gene expression and production in a time- and concentration-dependent manner via various signaling pathways including the protein kinase A, p38 mitogen-activated protein kinase, cJun N-terminal kinase, and IκB kinase pathways. Specific inhibition of MC2R and MC5R expression with short interfering Mc2r and Mc5r RNAs significantly attenuated the α-MSH-induced increase of intracellular cAMP and both the level of Il6 mRNA and secretion of IL6 in 3T3-L1 adipocytes. Finally, when injected into mouse tail vein, α-MSH dramatically increased the Il6 transcript levels in epididymal fat pads. These results suggest that α-MSH in addition to ACTH may function as a regulator of inflammation by regulating cytokine production.

Regulation of glucose transport in aortic smooth muscle cells by cAMP and cGMP

2001 ◽  
Vol 353 (3) ◽  
pp. 513-519 ◽  
Author(s):  
Christopher J. MacKENZIE ◽  
Jill M. WAKEFIELD ◽  
Fiona CAIRNS ◽  
Anna F. DOMINICZAK ◽  
Gwyn W. GOULD
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Smooth Muscle Cells ◽  
Primary Cultures ◽  
Muscle Cells ◽  
Mek Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Common Element ◽  
Dependent Manner ◽  
Concentration Dependent Manner

We have studied the ability of cGMP and cAMP to modulate platelet-derived growth factor (PDGF)-stimulated 2-deoxy-d-glucose (deGlc) transport in primary cultures of vascular smooth muscle cells (VMSC) from rat aorta. PDGF stimulated deGlc transport in a time- and concentration-dependent manner. 8-Bromo-cGMP and atrial natriuretic peptide(1–28) [ANP(1–28)] were found to reduce PDGF-stimulated deGlc transport without affecting basal (unstimulated) transport activity. In contrast, 8-bromo-cAMP and dibutyryl-cAMP stimulated basal deGlc transport 2-fold and were without effect on PDGF-stimulated deGlc transport. 8-Bromo-cGMP also inhibited 8-bromo-cAMP-stimulated deGlc transport. The stimulation of deGlc transport by PDGF was sensitive to the mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinase (ERK) kinase (MEK) inhibitor PD98059, and we show that ERK1/2 was activated by PDGF. Neither 8-bromo-cGMP nor ANP(1–28) inhibited PDGF-stimulated ERK activation, suggesting that the effects of cGMP and ANP(1–28) were not mediated by inhibition of this kinase. Our data also argue against a role for cGMP-dependent protein kinase in mediating the effects of cGMP or ANP(1–28). Collectively, our data suggest that in VSMC: (i) cGMP and cAMP have opposing effects on deGlc transport; (ii) PDGF and cAMP have common elements in the pathways by which they activate deGlc transport; and (iii) a common element may be the target of the cGMP-mediated inhibition of deGlc transport.

Signal transduction events involved in TPA downregulation of SP-A gene expression

2004 ◽  
Vol 286 (6) ◽  
pp. L1210-L1219 ◽  
Author(s):  
Olga L. Miakotina ◽  
Jeanne M. Snyder
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Surfactant Protein ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Novel Isoforms

Surfactant protein A (SP-A), the most abundant pulmonary surfactant protein, plays a role in innate host defense and blocks the inhibitory effects of serum proteins on surfactant surface tension-lowering properties. SP-A mRNA and protein are downregulated by phorbol esters (TPA) via inhibition of gene transcription. We evaluated the TPA signaling pathways involved in SP-A inhibition in a lung cell line, H441 cells. TPA caused sustained phosphorylation of p44/42 mitogen-activated protein kinase (MAPK), p38 MAPK, and c-Jun-NH2-terminal kinase. An inhibitor of conventional and novel isoforms of protein kinase C (PKC) and two inhibitors of p44/42 MAPK kinase partially or completely blocked the inhibitory effects of TPA on SP-A mRNA levels. In contrast, inhibitors of conventional PKC-α and -β, stress-activated protein kinases, protein phosphatases, protein kinase A, and the phosphatidylinositol 3-kinase pathway had no effect on the TPA-mediated inhibition of SP-A mRNA. TPA also stimulated the synthesis of c-Jun mRNA and protein in a time-dependent manner. Inhibitors of the p44/42 MAPK signaling pathway and PKC blocked the TPA-mediated phosphorylation of p44/42 MAPK and the increase in c-Jun mRNA. We conclude that TPA inhibits SP-A gene expression via novel isoforms of PKC, the p44/42 MAPK pathway, and the activator protein-1 complex.

β-Adrenergic agonists stimulate Mg2+ uptake in mouse distal convoluted tubule cells

2000 ◽  
Vol 279 (6) ◽  
pp. F1116-F1123 ◽  
Author(s):  
Hyung Sub Kang ◽  
Dirk Kerstan ◽  
Long-Jun Dai ◽  
Gordon Ritchie ◽  
Gary A. Quamme
Keyword(s):  
Protein Kinase ◽  
Intracellular Signaling ◽  
Distal Tubule ◽  
Distal Convoluted Tubule ◽  
Maximal Response ◽  
Intracellular Camp ◽  
Thick Ascending Limb ◽  
Dependent Manner ◽  
Adrenergic Agonists ◽  
Concentration Dependent Manner

β-Adrenergic agonists influence electrolyte reabsorption in the proximal tubule, loop of Henle, and distal tubule. Although isoproterenol enhances magnesium absorption in the thick ascending limb, it is unclear what effect, if any, β-adrenergic agonists have on tubular magnesium handling. The effects of isoproterenol were studied in immortalized mouse distal convoluted tubule (MDCT) cells by measuring cellular cAMP formation with radioimmunoassays and Mg2+ uptake with fluorescence techniques. Intracellular free Mg2+ concentration ([Mg2+]i) was measured in single MDCT cells by using microfluorescence with mag-fura-2. To assess Mg2+uptake, MDCT cells were first Mg2+ depleted to 0.22 ± 0.01 mM by culturing in Mg2+-free media for 16 h and then placed in 1.5 mM MgCl2, and the changes in [Mg2+]i were determined. [Mg2+]i returned to basal levels, 0.53 ± 0.02 mM, with a mean refill rate, d([Mg2+]i)/d t, of 168 ± 11 nM/s. Isoproterenol stimulated Mg2+ entry in a concentration-dependent manner, with a maximal response of 252 ± 11 nM/s, at a concentration of 10−7 M, that represented a 50 ± 7% increase in uptake rate above control values. This was associated with a sixfold increase in intracellular cAMP generation. Isoproterenol-stimulated Mg2+ uptake was completely inhibited with RpcAMPS, a protein kinase A inhibitor, and U-73122, a phospholipase C inhibitor, and partially blocked by RO 31–822, a protein kinase C inhibitor. Accordingly, isoproterenol-mediated Mg2+ entry rates involve multiple intracellular signaling pathways. Aldosterone potentiated isoproterenol-stimulated Mg2+ uptake (326 ± 31 nM/s), whereas elevation of extracellular Ca2+ inhibited isoproterenol-mediated cAMP accumulation and Mg2+ uptake, 117 ± 37 nM/s. These studies demonstrate that isoproterenol stimulates Mg2+ uptake in a cell line of mouse distal convoluted tubules that is modulated by hormonal and extracellular influences.

scholarly journals Mitogen-Activated Protein Kinase-Dependent Stimulation of Proliferation of Rat Lactotrophs in Culture by 3′,5′-Cyclic Adenosine Monophosphate*

Endocrinology ◽  
1999 ◽  
Vol 140 (6) ◽  
pp. 2850-2858 ◽  
Author(s):  
Shinichi Suzuki ◽  
Isao Yamamoto ◽  
Jun Arita
Keyword(s):  
Protein Kinase ◽  
Kinase Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Dopamine Receptor Agonist ◽  
Intracellular Camp ◽  
Pituitary Cells ◽  
Dependent Manner ◽  
Stimulatory Action ◽  
Mitogen Activated Protein ◽  
Brdu Labeling

Abstract Intracellular cAMP regulates cell proliferation as a second messenger of extracellular signals in a number of cell types. We investigated, by pharmacological means, whether an increase in intracellular cAMP levels changes proliferation rates of lactotrophs in primary culture, whether there are interactions between signal transduction pathways of cAMP and the growth factor insulin, and where the dopamine receptor agonist bromocriptine acts in the cAMP pathway to inhibit lactotroph proliferation. Rat anterior pituitary cells, cultured in serum-free medium, were treated with cAMP-increasing agents, followed by 5-bromo-2′-deoxyuridine (BrdU) to label proliferating pituitary cells. BrdU-labeling indices indicative of the proliferation rate of lactotrophs were determined by double immunofluorescence staining for PRL and BrdU. Treatment with forskolin (an adenylate cyclase activator) or (Bu)2cAMP (a membrane-permeable cAMP analog) increased BrdU-labeling indices of lactotrophs in a dose- and incubation time-dependent manner. The cAMP-increasing agents were also effective in increasing BrdU-labeling indices in populations enriched for lactotrophs by differential sedimentation. The stimulatory action of forskolin was observed, regardless of concentrations of insulin that were added in combination with forskolin. Inhibition of the action of endogenous cAMP by H89 or KT5720, a protein kinase A inhibitor, attenuated an increase in BrdU-labeling indices by insulin treatment. On the other hand, the specific mitogen-activated protein kinase inhibitor PD98059, which was effective in blocking the mitogenic action of insulin, markedly suppressed the forskolin-induced increase in BrdU-labeling indices. (Bu)2cAMP antagonized not only inhibition of BrdU labeling indices but also changes in cell shape induced by bromocriptine treatment, although forskolin did not have such an antagonizing effect. These results suggest that: 1) intracellular cAMP plays a stimulatory role in the regulation of lactotroph proliferation; 2) cAMP and insulin/mitogen-activated protein kinase signalings require each other for their mitogenic actions; and 3) the antimitogenic action of bromocriptine is, at least in part, caused by inhibition of cAMP production.

scholarly journals Chrysoeriol Enhances Melanogenesis in B16F10 Cells Through the Modulation of the MAPK, AKT, PKA, and Wnt/β-Catenin Signaling Pathways

2022 ◽  
Vol 17 (1) ◽  
pp. 1934578X2110692
Author(s):  
So-Yeon Oh ◽  
Chang-Gu Hyun
Keyword(s):  
Protein Kinase ◽  
Signaling Pathways ◽  
Transcriptional Activation ◽  
Glycogen Synthase ◽  
Multidrug Resistant ◽  
Antimicrobial Activities ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
B16f10 Cells

Chrysoeriol is a 3′-O-methoxy flavone, chemically a derivative of luteolin, which is commonly found across the plant kingdom. Chrysoeriol is of great scientific interest because of its promising anti-inflammatory, anti-cancer, antioxidative, anti-lipase, anti-xanthin oxidase, and antimicrobial activities against multidrug-resistant (MDR) bacterial pathogens; however, its effects on melanogenesis have not yet been elucidated. Here, we report a novel effect of chrysoeriol on melanogenesis in B16F10 cells. Chrysoeriol treatment significantly increased the expression of the melanogenic enzymes tyrosinase (TRY), tyrosinase-related protein-1 (TRP-1), and TRP-2 and upregulated the expression of microphthalmia-associated transcription factor (MITF) in a concentration-dependent manner. Furthermore, chrysoeriol suppressed the phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (AKT) in a concentration-dependent manner. In addition, chrysoeriol treatment increased the phosphorylation of p38 mitogen-activated protein kinase (MAPK), glycogen synthase kinase (GSK)-3β, β-catenin, and protein kinase A (PKA) and decreased the production of β-catenin, which is involved in the transcriptional activation of MITF in melanogenesis. Finally, the structure–activity relationship (SAR) of chrysoeriol and its derivatives, including luteolin and apigenin, with regard to their melanin inhibitory activity was also investigated; we identified the significance of the 4′-OH group and C-3′ methoxylation in melanogenesis. Together, these findings indicate that chrysoeriol promotes melanogenesis in B16F10 cells by upregulating the expression of melanogenic enzymes through the MAPK, phosphatidylinositol 3-kinase (PI3K)/AKT, PKA, and Wnt/β-catenin signaling pathways; thus, chrysoeriol may be used as a cosmetic ingredient to promote melanogenesis or as a therapeutic agent against hypopigmentation disorders.

PGE2 stimulates Mg2+ uptake in mouse distal convoluted tubule cells

1998 ◽  
Vol 275 (5) ◽  
pp. F833-F839 ◽  
Author(s):  
Long-Jun Dai ◽  
Brian Bapty ◽  
Gordon Ritchie ◽  
Gary A. Quamme
Keyword(s):  
Protein Kinase ◽  
Intracellular Signaling ◽  
Distal Convoluted Tubule ◽  
Maximal Response ◽  
Prostaglandin E ◽  
Intracellular Camp ◽  
Thick Ascending Limb ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Camp Generation

Prostaglandins have diverse effects on renal electrolyte reabsorption, inhibiting NaCl absorption in the thick ascending limb and modulating sodium and calcium transport in cortical collecting cells. It is unclear what effect, if any, prostaglandins have on tubular magnesium handling. The effects of prostaglandin E2(PGE2) were studied on immortalized mouse distal convoluted tubule (MDCT) cells by measuring cellular cAMP formation with radioimmunoassays and Mg2+ uptake with fluorescence techniques. Intracellular free Mg2+ concentration ([Mg2+]i) was measured on single MDCT cells using microfluorescence with mag-fura 2. To assess Mg2+ uptake, MDCT cells were first Mg2+ depleted to 0.22 ± 0.01 mM by culturing in Mg2+-free media for 16 h and then placed in 1.5 mM MgCl2, and the changes in [Mg2+]iwere determined. [Mg2+]ireturned to basal levels, 0.53 ± 0.02 mM, with a mean refill rate, d([Mg2+]i)/d t, of 173 ± 8 nM/s. Indomethacin, 5 μM, diminished basal Mg2+ uptake, suggesting that endogenous prostaglandins may stimulate Mg2+ entry in control cells. PGE2 stimulated Mg2+ entry in a concentration-dependent manner with maximal response of 311 ± 12 nM/s, at a concentration of 10−7 M, which represented an 80 ± 3% increase in uptake rate above control values. This was associated with a sixfold increase in intracellular cAMP generation. PGE2-stimulated Mg2+ uptake was completely inhibited with the Rp diastereoisomer of adenosine 3′,5′-cyclic monophosphothionate (Rp-cAMPS), a protein kinase A inhibitor, and U-73122, a phospholipase C inhibitor, and partially by chelerythrine, a protein kinase C inhibitor. Accordingly, PGE2-mediated Mg2+ entry rates involve multiple intracellular signaling pathways. These studies demonstrate that PGE2 stimulates Mg2+ uptake in a cell line of MDCT.

scholarly journals New Benzimidazothiazolone Derivatives as Tyrosinase Inhibitors with Potential Anti-Melanogenesis and Reactive Oxygen Species Scavenging Activities

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1078
Author(s):  
Hee Jin Jung ◽  
Dong Chan Choi ◽  
Sang Gyun Noh ◽  
Heejeong Choi ◽  
Inkyu Choi ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Inhibitory Activity ◽  
Camp Response Element Binding ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Docking Simulations ◽  
B16f10 Cells ◽  
Tyrosinase Inhibitors

Thirteen (Z)-2-(substituted benzylidene)benzimidazothiazolone analogs were synthesized and evaluated for their inhibitory activity against mushroom tyrosinase. Among the compounds synthesized, compounds 1–3 showed greater inhibitory activity than kojic acid (IC50 = 18.27 ± 0.89 μM); IC50 = 3.70 ± 0.51 μM for 1; IC50 = 3.05 ± 0.95 μM for 2; and IC50 = 5.00 ± 0.38 μM for 3, and found to be competitive tyrosinase inhibitors. In silico molecular docking simulations demonstrated that compounds 1–3 could bind to the catalytic sites of tyrosinase. Compounds 1–3 inhibited melanin production and cellular tyrosinase activity in a concentration-dependent manner. Notably, compound 2 dose-dependently scavenged ROS in B16F10 cells. Furthermore, compound 2 downregulated the protein kinase A (PKA)/cAMP response element-binding protein (CREB) and mitogen-activated protein kinase (MAPK) signaling pathways, which led to a reduction in microphthalmia-associated transcription factor (MITF) expression, and decreased tyrosinase, tyrosinase related protein 1 (TRP1), and TRP2 expression, resulting in anti-melanogenesis activity. Hence, compound 2 may serve as an anti-melanogenic agent against hyperpigmentation diseases.

scholarly journals Allium cepaExtract and Quercetin Protect Neuronal Cells from Oxidative Stress via PKC-εInactivation/ERK1/2 Activation

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Bo Kyung Lee ◽  
Yi-Sook Jung
Keyword(s):  
Oxidative Stress ◽  
Protein Kinase ◽  
Molecular Mechanisms ◽  
Antioxidant Activities ◽  
Neuroprotective Effect ◽  
Neuronal Cells ◽  
Mitogen Activated Protein Kinase ◽  
Protective Mechanism ◽  
Dependent Manner ◽  
Concentration Dependent Manner

Oxidative stress plays an important role in the pathophysiology of various neurologic disorders.Allium cepaextract (ACE) and their main flavonoid component quercetin (QCT) possess antioxidant activities and protect neurons from oxidative stress. We investigated the underlying molecular mechanisms, particularly those linked to the antioxidant effects of the ACE. Primary cortical neuronal cells derived from mouse embryos were preincubated with ACE or QCT for 30 min and exposed to L-buthionine sulfoximine for 4~24 h. We found that ACE and QCT significantly decreased neuronal death and the ROS increase induced by L-buthionine-S, R-sulfoximine (BSO) in a concentration-dependent manner. Furthermore, ACE and QCT activated extracellular signal-regulated kinase 1/2 (ERK1/2), leading to downregulation of protein kinase C-ε(PKC-ε) in BSO-stimulated neuronal cells. In addition, ACE and QCT decreased the phosphorylated levels of p38 mitogen-activated protein kinase. Our results provide new insight into the protective mechanism of ACE and QCT against oxidative stress in neuronal cells. The results suggest that the inactivation of PKC-εinduced by phosphorylating ERK1/2 is responsible for the neuroprotective effect of ACE and QCT against BSO-induced oxidative stress.

Sphingosine Blocks Human Polymorphonuclear Leukocyte Phagocytosis Through Inhibition of Mitogen-Activated Protein Kinase Activation

Blood ◽  
1999 ◽  
Vol 93 (2) ◽  
pp. 686-693 ◽  
Author(s):  
Evelin M.B. Raeder ◽  
Pamela J. Mansfield ◽  
Vania Hinkovska-Galcheva ◽  
Lars Kjeldsen ◽  
James A. Shayman ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Polymorphonuclear Leukocyte ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Human Polymorphonuclear Leukocyte ◽  
Calcium Dependent ◽  
Mitogen Activated Protein ◽  
Erk2 Activation

Abstract In the present study, we investigated the mechanism by which sphingosine and its analogues, dihydrosphingosine and phytosphingosine, inhibit polymorphonuclear leukocyte (PMN) phagocytosis of IgG-opsonized erythrocytes (EIgG) and inhibit ERK1 and ERK2 phosphorylation. We used antibodies that recognized the phosphorylated forms of ERK1 (p44) and ERK2 (p42) (extracellular signal-regulated protein kinases 1 and 2). Sphingoid bases inhibited ERK1 and ERK2 activation and phagocytosis of EIgG in a concentration-dependent manner. Incubation with glycine, N,N′-[1,2-ethanediylbis(oxy-2,1-phenylene)]bis[N-[2-[(acetyloxy)methoxy]-2-oxoethyl]]-bis[(acetyloxy)methyl]ester (BAPTA,AM), an intracellular chelator of calcium, failed to block either phagocytosis or ERK1 and ERK2 phosphorylation, consistent with the absence of a role for a calcium-dependent protein kinase C (PKC) in ERK1 and ERK2 phosphorylations. Western blotting demonstrated that sphingosine inhibited the translocation of Raf-1 and PKCδ from PMN cytosol to the plasma membrane during phagocytosis. These data are consistent with the interpretation that sphingosine regulates ERK1 and ERK2 phosphorylation through inhibition of PKCδ, and this in turn leads to inhibition of Raf-1 translocation to the plasma membrane. Consistent with this interpretation, the sphingosine-mediated inhibition of phagocytosis, ERK2 activation, and PKCδ translocation to the plasma membrane could be abrogated with a cell-permeable diacylglycerol analog. The increase in the diacylglycerol mass correlated with the translocation of PKCδ and Raf-1 to the plasma membrane by 3 minutes after the initiation of phagocytosis. Additionally, the diacylglycerol analog enhanced phagocytosis by initiating activation of PKCδ and its translocation to the plasma membrane. Because PMN generate sufficient levels of sphingosine by 30 minutes during phagocytosis of EIgG to inhibit phagocytosis, it appears that sphingosine can serve as an endogenous regulator of EIgG-mediated phagocytosis by downregulating ERK activation.

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