Bile acids stimulate PKCα autophosphorylation and activation: role in the attenuation of prostaglandin E1-induced cAMP production in human dermal fibroblasts

2006 ◽  
Vol 291 (2) ◽  
pp. G275-G287 ◽  
Author(s):  
Man Le ◽  
Lada Krilov ◽  
Jianping Meng ◽  
Kelli Chapin-Kennedy ◽  
Susan Ceryak ◽  
...  

The aim was to identify the specific PKC isoform(s) and their mechanism of activation responsible for the modulation of cAMP production by bile acids in human dermal fibroblasts. Stimulation of fibroblasts with 25–100 μM of chenodeoxycholic acid (CDCA) and ursodeoxycholic acid (UDCA) led to YFP-PKCα and YFP-PKCδ translocation in 30–60 min followed by a transient 24- to 48-h downregulation of the total PKCα, PKCδ, and PKCε protein expression by 30–50%, without affecting that of PKCζ. Increased plasma membrane translocation of PKCα was associated with an increased PKCα phosphorylation, whereas increased PKCδ translocation to the perinuclear domain was associated with an increased accumulation of phospho-PKCδ Thr505 and Tyr311 in the nucleus. The PKCα specificity on the attenuation of cAMP production by CDCA was demonstrated with PKC downregulation or inhibition, as well as PKC isoform dominant-negative mutants. Under these same conditions, neither phosphatidylinositol 3-kinase, p38 MAP kinase, p42/44 MAP kinase, nor PKA inhibitors had any significant effect on the CDCA-induced cAMP production attenuation. CDCA concentrations as low as 10 μM stimulated PKCα autophosphorylation in vitro. This bile acid effect required phosphatidylserine and was completely abolished by the presence of Gö6976. CDCA at concentrations less than 50 μM enhanced the PKCα activation induced by PMA, whereas greater CDCA concentrations reduced the PMA-induced PKCα activation. CDCA alone did not affect PKCα activity in vitro. In conclusion, although CDCA and UDCA activate different PKC isoforms, PKCα plays a major role in the bile acid-induced inhibition of cAMP synthesis in fibroblasts. This study emphasizes potential consequences of increased systemic bile acid concentrations and cellular bile acid accumulation in extrahepatic tissues during cholestatic liver diseases.

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 479 ◽  
Author(s):  
Lin ◽  
Wu ◽  
Hou ◽  
Chien ◽  
Chang ◽  
...  

Ultraviolet (UV) exposure has been demonstrated as the most critical factor causing extrinsic skin aging and inflammation. This study explored the protective effects and mechanisms of sesamin against skin photodamage. Sesamin reduced intracellular reactive oxygen species production after UVB irradiation in human dermal fibroblasts. The sesamin treatment attenuated mitogen-activated protein (MAP) kinase phosphorylation and matrix metalloproteinase (MMPs) overexpression induced by UVB exposure, and it significantly enhanced the tissue inhibitor of metalloproteinase-1 protein expression. Sesamin also elevated the total collagen content in human fibroblasts by inhibiting UVB-induced mothers against decapentaplegic homolog 7 (Smad7) protein expression. Sesamin reduced UVB-induced inducible nitric oxide synthase (i-NOS) and cyclooxygenase-2 (COX-2) overexpression and inhibited nuclear factor-kappa B (NF-κB) translocation. Moreover, sesamin may regulate the c-Jun N-terminal kinases (JNK) and p38 MAP kinase pathways, which inhibit COX-2 expression. Sesamin could reduce UVB-induced inflammation, epidermal hyperplasia, collagen degradation, and wrinkle formation in hairless mice. It also reduced MMP-1, interleukin (IL-1), i-NOS, and NF-κB in the mouse skin. These results demonstrate that sesamin had antiphotodamage and anti-inflammatory activities. Sesamin has potential for use as a skin protection agent in antiphotodamage and skin care products.


2002 ◽  
Vol 9 (6) ◽  
pp. 1169-1174 ◽  
Author(s):  
Naoki Koide ◽  
Tsuyoshi Sugiyama ◽  
Isamu Mori ◽  
Mya Mya Mu ◽  
Teruaki Hamano ◽  
...  

ABSTRACT The in vitro effects of gamma interferon (IFN-γ) on the mouse CD5+ B1-cell line, TH2.52, a hybridoma between mouse B lymphoma and mouse splenic B cells that expresses a series of B1 markers, were investigated. A significant number of macrophage-like cells appeared in the cultures of TH2.52 cells exposed to IFN-γ, these adhering to plastic dishes and exhibiting phagocytic activity. Positive for esterase staining, the macrophage-like cells returned to the original TH2.52 morphology upon removal of IFN-γ. The change was prevented by treatment with SB202190, an inhibitor of p38 mitogen-activated protein (MAP) kinase and by transfection of a p38 MAP kinase dominant-negative mutant. Further, interleukin-4 (IL-4) inhibited IFN-γ-induced phosphorylation of p38 MAP kinase and the appearance of macrophage-like cells. IFN-γ and IL-4 exhibited contradictory actions on morphological change of CD5+ B1 cells into macrophage-like cells. Differential regulation of CD5+ B1 cells by IFN-γ, a Th1 cytokine, and IL-4, a Th2 cytokine, may have clear immunological significance.


2009 ◽  
Vol 4 (2) ◽  
pp. 025008 ◽  
Author(s):  
Ikuko Machida-Sano ◽  
Yasushi Matsuda ◽  
Hideo Namiki

2000 ◽  
Vol 20 (4) ◽  
pp. 1140-1148 ◽  
Author(s):  
Dae-Won Kim ◽  
Brent H. Cochran

ABSTRACT We have previously shown that TFII-I enhances transcriptional activation of the c-fos promoter through interactions with upstream elements in a signal-dependent manner. Here we demonstrate that activated Ras and RhoA synergize with TFII-I for c-fospromoter activation, whereas dominant-negative Ras and RhoA inhibit these effects of TFII-I. The Mek1 inhibitor, PD98059 abrogates the enhancement of the c-fos promoter by TFII-I, indicating that TFII-I function is dependent on an active mitogen-activated protein (MAP) kinase pathway. Analysis of the TFII-I protein sequence revealed that TFII-I contains a consensus MAP kinase interaction domain (D box). Consistent with this, we have found that TFII-I forms an in vivo complex with extracellular signal-related kinase (ERK). Point mutations within the consensus MAP kinase binding motif of TFII-I inhibit its ability to bind ERK and its ability to enhance the c-fos promoter. Therefore, the D box of TFII-I is required for its activity on the c-fos promoter. Moreover, the interaction between TFII-I and ERK can be regulated. Serum stimulation enhances complex formation between TFII-I and ERK, and dominant-negative Ras abrogates this interaction. In addition, TFII-I can be phosphorylated in vitro by ERK and mutation of consensus MAP kinase substrate sites at serines 627 and 633 impairs the phosphorylation of TFII-I by ERK and its activity on the c-fos promoter. These results suggest that ERK regulates the activity of TFII-I by direct phosphorylation.


Marine Drugs ◽  
2018 ◽  
Vol 16 (7) ◽  
pp. 239 ◽  
Author(s):  
Lei Wang ◽  
WonWoo Lee ◽  
Jae Oh ◽  
Yong Cui ◽  
BoMi Ryu ◽  
...  

Our previous study evaluated the antioxidant activities of sulfated polysaccharides from Celluclast-assisted extract of Hizikia fusiforme (HFPS) in vitro in Vero cells and in vivo in zebrafish. The results showed that HFPS possesses strong antioxidant activity and suggested the potential photo-protective activities of HFPS. Hence, in the present study, we investigated the protective effects of HFPS against ultraviolet (UV) B-induced skin damage in vitro in human dermal fibroblasts (HDF cells). The results indicate that HFPS significantly reduced intracellular reactive oxygen species (ROS) level and improved the viability of UVB-irradiated HDF cells in a dose-dependent manner. Furthermore, HFPS significantly inhibited intracellular collagenase and elastase activities, remarkably protected collagen synthesis, and reduced matrix metalloproteinases (MMPs) expression by regulating nuclear factor kappa B (NF-κB), activator protein 1 (AP-1), and mitogen-activated protein kinases (MAPKs) signaling pathways in UVB-irradiated HDF cells. These results suggest that HFPS possesses strong UV protective effect, and can be a potential ingredient in the pharmaceutical and cosmetic industries.


Phytomedicine ◽  
2018 ◽  
Vol 51 ◽  
pp. 94-103 ◽  
Author(s):  
Debayan Goswami ◽  
Ananya Das Mahapatra ◽  
Subhadip Banerjee ◽  
Amit Kar ◽  
Durbadal Ojha ◽  
...  

2021 ◽  
Author(s):  
Hijam Nonibala ◽  
Braj Bansh Prasad Gupta

Abstract Transcription of arylalkylamine N-acetyltransferase 2 (aanat2) gene leads to formation of AANAT2 - the rate-limiting enzyme in melatonin synthesis pathway in photosensitive fish pineal organ. However, unlike in avian and mammalian pineal gland, there is practically no information on signal transduction pathway(s) involved in regulation of aanat2 gene transcription in the fish pineal organ. Therefore, we investigated the role of important molecular components of signalling via cAMP, cGMP, Ca2+ involving PKA, PKG, PKC, MeK and p38 MAP kinase as well as possible role of serine/threonine phosphatases, CREB and CBP using their specific inhibitors and/or activators in aanat2 gene transcription in the fish pineal organ maintained under in vitro culture-conditions. db-cAMP and db-cGMP stimulated the expression of aanat2 gene. db-cAMP- and cGMP-induced aanat2 gene expression was significantly reduced in the presence of H-89 (specific inhibitor of PKA), KT5823 (specific inhibitor of PKG), chelerythrine chloride (specific inhibitor of PKC), U0126 ethanolate (specific inhibitor of MeK) and SB 202190 monohydrochloride hydrate (specific inhibitor of p38 MAP kinase). Inhibitors of PP1 and PP2A significantly increased aanat2 gene expression as well as significantly reduced cAMP- and cGMP-induced gene transcription, while inhibitor of PP2B had no effect on aanat2 gene expression. Inhibitors of both CREB and CBP-CREB interaction completely blocked cAMP-induced aanat2 gene transcription. Based on these findings, we suggest that cAMP, cGMP and Ca2+ stimulate aanat2 gene transcription via PKA, PKG and PKC, respectively. Further, protein phosphatases and CBP-CREB-CRE pathway are actively involved in regulation of on aanat2 gene expression in the fish pineal organ.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Stef De Lombaerde ◽  
Ken Kersemans ◽  
Sara Neyt ◽  
Jeroen Verhoeven ◽  
Christian Vanhove ◽  
...  

Introduction. An in vivo determination of bile acid hepatobiliary transport efficiency can be of use in liver disease and preclinical drug development. Given the increased interest in bile acid Positron Emission Tomography- (PET-) imaging, a further understanding of the impact of 18-fluorine substitution on bile acid handling in vitro and in vivo can be of significance. Methods. A number of bile acid analogues were conceived for nucleophilic substitution with [18F]fluoride: cholic acid analogues of which the 3-, 7-, or 12-OH function is substituted with a fluorine atom (3α-[18F]FCA; 7β-[18F]FCA; 12β-[18F]FCA); a glycocholic and chenodeoxycholic acid analogue, substituted on the 3-position (3β-[18F]FGCA and 3β-[18F]FCDCA, resp.). Uptake by the bile acid transporters NTCP and OATP1B1 was evaluated with competition assays in transfected CHO and HEK cell lines and efflux by BSEP in membrane vesicles. PET-scans with the tracers were performed in wild-type mice (n=3 per group): hepatobiliary transport was monitored and compared to a reference tracer, namely, 3β-[18F]FCA. Results. Compounds 3α-[18F]FCA, 3β-[18F]FGCA, and 3β-[18F]FCDCA were synthesized in moderate radiochemical yields (4–10% n.d.c.) and high radiochemical purity (>99%); 7β-[18F]FCA and 12β-[18F]FCA could not be synthesized and included further in this study. In vitro evaluation showed that 3α-FCA, 3β-FGCA, and 3β-FCDCA all had a low micromolar Ki-value for NTCP, OATP1B1, and BSEP. In vivo, 3α-[18F]FCA, 3β-[18F]FGCA, and 3β-[18F]FCDCA displayed hepatobiliary transport with varying efficiency. A slight yet significant difference in uptake and efflux rate was noticed between the 3α-[18F]FCA and 3β-[18F]FCA epimers. Conjugation of 3β-[18F]FCA with glycine had no significant effect in vivo. Compound 3β-[18F]FCDCA showed a significantly slower hepatic uptake and efflux towards gallbladder and intestines. Conclusion. A set of 18F labeled bile acids was synthesized that are substrates of the bile acid transporters in vitro and in vivo and can serve as PET-biomarkers for hepatobiliary transport of bile acids.


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