Effect of the configuration mixing on the polarization and angular distribution of x-ray line emissions following electron-impact excitation of Ne-like ions.

We present a systematic theoretical study on the angular distribution and linear polarization of x-ray line emissions of neon-like ions following the electron-impact excitation from the ground state to the excited levels [(2p5)1/23d3/2]J=1, [(2p5)3/23d5/2]J=1, [(2p5)3/23d3/2]J=1, and [(2p5)1/23s]J=1. The cross sections are calculated by using the flexible atomic code under configuration-interaction plus many-body perturbation theory method. The angular distribution and linear polarization are obtained based on density matrix theory. Emphasis has been placed on the effect of the configuration mixing on the angular distribution and polarization. It has been proved that the strong mixing of configuration [(2p5)3/23d3/2]J=1 with configuration [(2p5)1/23s]J=1 can result in the abrupt change of Z-dependence of angular distribution and polarization. It indicates that angular distribution and polarization can be expected to serve as a tool for investigation of configuration mixing effect.

Research trends on platelet-rich plasma in the treatment of wounds during 2002-2021: A 20-year bibliometric analysis.

Platelet-rich plasma (PRP) has attracted attention because of its potential to accelerate the wound healing process. However, resources for evaluating research trends in the treatment of wounds with PRP were limited. In this study, we aimed to make a bibliometric analysis of the literature related to PRP in the treatment of wounds and explore the research status, hotspots and frontiers in this field in recent 20 years. Studies about PRP treatment for wounds from 2002 to 2021 were retrieved from the Science Citation Index Expanded (SCI-E) of Web of Science (WOS) database. Visualisation softwares such as VOSviewer and SCImago Graphica, and CiteSpace were used to analyse the research trends and features. A total of 1748 studies were identified in the SCI-Expanded from 2002 to 2021. The number of publications on PRP in the treatment of wounds has shown an increasing trend, from 6 (in 2002) to 228 (in 2021). The papers published in the United States have led in times cited (14637) and H-index (63). Though Italy was slightly lower than China in the number of publications, the H-index and average cited (47, 28.45) were higher than that of China (38, 27.01). The strongest keyword was "fibrin" (strength = 13.07), and the longest burst duration keyword was "thrombin" (began in 2002 and ended in 2014). The largest 10 co-citation clusters are as follows: endothelial cell proliferation (#0), regenerative medicine-associated treatment (#1), diabetic wound healing (#2), autologous derived (#3), platelet-rich fibrin (#4), tissue engineering (#5), regenerative potential (#6), clinical randomised trial (#7), histologic observation (#8), and wound bacteria (#9). The United States has made the most outstanding contribution in this field. Chinese researchers need to enhance the quality of publications further. Wound Repair Regen. is the most noteworthy journal. The mechanism of growth factors of PRP, combination therapy, preparation of PRP, and related clinical trials may be topics that need attention.

Regulations of expressions of rat/human sulfotransferases by anticancer drug, nolatrexed, and micronutrients.

Cancer is related to the cellular proliferative state. Increase in cell-cycle regulatory function augments cellular folate pool. This pathway is therapeutically targeted. A number of drugs influences this metabolism, that is, folic acid, folinic acid, nolatrexed, and methotrexate. Our previous study showed methotrexate influences on rat/human sulfotransferases. Present study explains the effect of nolatrexed (widely used in different cancers) and some micronutrients on the expressions of rat/human sulfotransferases. Female Sprague-Dawley rats were treated with nolatrexed (01-100 mg/kg) and rats of both sexes were treated to folic acid (100, 200, or 400 mg/kg) for 2-weeks and their aryl sulfotransferase-IV (AST-IV; ß-napthol sulfation) and sulfotransferase (STa; DHEA sulfation) activities, protein expression (western blot) and mRNA expression (RT-PCR) were tested. In human-cultured hepatocarcinoma (HepG2) cells nolatrexed (1 nM-1.2 mM) or folinic acid (10 nM-10 µM) were applied for 10 days. Folic acid (0-10 µM) was treated to HepG2 cells. PPST (phenol catalyzing), MPST (dopamine and monoamine), DHEAST (dehydroepiandrosterone and DHEA), and EST (estradiol sulfating) protein expressions (western-blot) were tested in HepG2 cells. Present results suggest that nolatrexed significantly increased sulfotransferases expressions in rat (protein, STa, F = 4.87, P < 0.05/mRNA, AST-IV, F = 6.702, P < 0.014; Student's t test, P < 0.01-0.05) and HepG2 cells. Folic acid increased sulfotransferases activity/protein in gender-dependant manner. Both folic and folinic acid increased several human sulfotransferases isoforms with varied level of significance (least or no increase at highest dose) in HepG2 cells pointing its dose-dependent multiphasic responses. The clinical importance of this study may be furthered in the verification of sulfation metabolism of several exogenous/endogenous molecules, drug-drug interaction and their influences on cancer pathophysiological processes. Further studies are necessary.

The urea transporter UT-A1 plays a predominant role in a urea-dependent urine-concentrating mechanism.

Urea transporters are a family of urea-selective channel proteins expressed in multiple tissues that play an important role in the urine-concentrating mechanism of the mammalian kidney. Previous studies have shown that knockout of urea transporter (UT)-B, UT-A1/A3, or all UTs leads to urea-selective diuresis, indicating that urea transporters have important roles in urine concentration. Here, we sought to determine the role of UT-A1 in the urine-concentrating mechanism in a newly developed UT-A1-knockout mouse model. Phenotypically, daily urine output in UT-A1-knockout mice was nearly 3-fold that of WT mice and 82% of all-UT-knockout mice, and the UT-A1-knockout mice had significantly lower urine osmolality than WT mice. After 24-h water restriction, acute urea loading, or high-protein (40%) intake, UT-A1-knockout mice were unable to increase urine-concentrating ability. Compared with all-UT-knockout mice, the UT-A1-knockout mice exhibited similarly elevated daily urine output and decreased urine osmolality, indicating impaired urea-selective urine concentration. Our experimental findings reveal that UT-A1 has a predominant role in urea-dependent urine-concentrating mechanisms, suggesting that UT-A1 represents a promising diuretic target.

Breast cancer pathogenesis is linked to the intra-tumoral estrogen sulfotransferase (hSULT1E1) expressions regulated by cellular redox dependent Nrf-2/NFκß interplay.

BACKGROUND: Estrogen sulfotransferase catalyzes conjugation of sulfuryl-group to estradiol/estrone and regulates E2 availability/activity via estrogen-receptor or non-receptor mediated pathways. Sulfoconjugated estrogen fails to bind estrogen-receptor (ER). High estrogen is a known carcinogen in postmenopausal women. Reports reveal a potential redox-regulation of hSULT1E1/E2-signalling. Further, oxidatively-regulated nuclear-receptor-factor 2 (Nrf2) and NFκß in relation to hSULT1E1/E2 could be therapeutic-target via cellular redox-modification. METHODS: Here, oxidative stress-regulated SULT1E1-expression was analyzed in human breast carcinoma-tissues and in rat xenografted with human breast-tumor. Tumor and its surrounding tissues were obtained from the district-hospital. Intracellular redox-environment of tumors was screened with some in vitro studies. RT-PCR and western blotting was done for SULT1E1 expression. Immunohistochemistry was performed to analyze SULT1E1/Nrf2/NFκß localization. Tissue-histoarchitecture/DNA-stability (comet assay) studies were done. RESULTS: Oxidative-stress induces SULT1E1 via Nrf2/NFκß cooperatively in tumor-pathogenesis to maintain the required proliferative-state under enriched E2-environment. Higher malondialdehyde/non-protein-soluble-thiol with increased superoxide-dismutase/glutathione-peroxidase/catalase activities was noticed. SULT1E1 expression and E2-level were increased in tumor-tissue compared to their corresponding surrounding-tissues. CONCLUSIONS: It may be concluded that tumors maintain a sustainable oxidative-stress through impaired antioxidants as compared to the surrounding. Liver-tissues from xenografted rat manifested similar E2/antioxidant dysregulations favoring pre-tumorogenic environment.

Dependence between estrogen sulfotransferase (SULT1E1) and nuclear transcription factor Nrf-2 regulations via oxidative stress in breast cancer.

Human estrogen sulfotransferase (SULT1E1) and nuclear factor erythroid 2-related factor 2 (Nrf-2) expression influences each other in advanced human breast carcinogenesis. The difference in the metabolism of estradiol (E2) in pre- and post-menopausal women remains to be connected with post-menopausal breast cancer. A synergism between ROS production and E2 generation has been demonstrated. No definite mechanism for simultaneous functions of Nrf2, oxidative stress E2 regulating enzymes (SULT1E1) has been yet clarified. Our present review demonstrates that ROS dependent regulation of Nrf-2 is one of the most important determinants of E2 regulation by altering SULT1E1 expression. This study also focuses the idea that estrogen receptor cased subtypes of cancer may have different molecular environments which has an impact on the therapeutic efficacy.

Dendrigraft poly-L-lysines delivery of DNA vaccine effectively enhances the immunogenic responses against H9N2 avian influenza virus infection in chickens.

Biodegradable nanomaterials can protect antigens from degradation, promote cellular absorption, and enhance immune responses. We constructed a eukaryotic plasmid [pCAGGS-opti441-hemagglutinin (HA)] by inserting the optimized HA gene fragment of H9N2 AIV into the pCAGGS vector. The pCAGGS-opti441-HA/DGL was developed through packaging the pCAGGS-opti441-HA with dendrigraft poly-l-lysines (DGLs). DGL not only protected the pCAGGS-opti441-HA from degradation, but also exhibited high transfection efficiency. Strong cellular immune responses were induced in chickens immunized with the pCAGGS-opti441-HA/DGL. The levels of IFN-γ and IL-2, and lymphocyte transformation rate of the vaccinated chickens increased at the third week post the immunization. For the vaccinated chickens, T lymphocytes were activated and proliferated, the numbers of CD3+CD4+ and CD4+/CD8+ increased, and the chickens were protected completely against H9N2 AIV challenge. This study provides a method for the development of novel AIV vaccines, and a theoretical basis for the development of safe and efficient gene delivery carriers.

High glucose reduces expression of podocin in cultured human podocytes by stimulating TRPC6.

The transient receptor potential canonical 6 (TRPC6) channel and podocin are colocalized in the glomerular slit diaphragm as an important complex to maintain podocyte function. Gain of TRPC6 function and loss of podocin function induce podocyte injury. We have previously shown that high glucose induces apoptosis of podocytes by activating TRPC6; however, whether the activated TRPC6 can alter podocin expression remains unknown. Western blot analysis and confocal microscopy were used to examine both expression levels of TRPC6, podocin, and nephrin and morphological changes of podocytes in response to high glucose. High glucose increased the expression of TRPC6 but reduced the expression of podocin and nephrin, in both cultured human podocytes and type 1 diabetic rat kidneys. The decreased podocin was diminished in TRPC6 knockdown podocytes. High glucose elevated intracellular Ca2+ in control podocytes but not in TRPC6 knockdown podocytes. High glucose also elevated the expression of a tight junction protein, zonula occludens-1, and induced the redistribution of zonula occludens-1 and loss of podocyte processes. These data together suggest that high glucose reduces protein levels of podocin by activating TRPC6 and induces morphological changes of cultured podocytes.

Tretinoin enhances minoxidil response in androgenetic alopecia patients by upregulating follicular sulfotransferase enzymes.

Minoxidil sulfate is the active metabolite required to exert the vasodilatory and hair growing effects of minoxidil. For hair growth, sulfotransferase enzymes expressed in outer root sheath of the hair follicle sulfonate minoxidil. The large intra-subject variability in follicular sulfotransferase was found to predict minoxidil response and thus explain the low response rate to topical minoxidil in the treatment of androgenetic alopecia. A method to increase minoxidil response would be of significant clinical utility. Retinoids have been reported to increase minoxidil response. The purported mechanism of action was retinoid modulation of skin permeation to minoxidil; however, evidence to the contrary supports retinoids increase dermal thickness. In order to elucidate the effect of topical retinoids on minoxidil response, we studied the effect of topical tretinoin on follicular sulfotransferase. In this study, we demonstrate that topical tretinoin application influences the expression of follicular sulfotransferase. Of clinical significance, in our cohort, 43% of subjects initially predicted to be nonresponders to minoxidil were converted to responders following 5 days of topical tretinoin application. To the best of our knowledge, this is the first study to elucidate the interaction mechanism between topical minoxidil and retinoids and thus provides a pathway for the development of future androgenetic alopecia treatments.

The role of galectin-3 in heart failure and cardiovascular disease.

Galectin-3, a ß-galactoside-binding lectin, is a new important player in the progression of heart failure (HF) and is also linked to poor outcome in patients with cardiovascular disease. Genetic or pharmacological inhibition of galectin-3 slows down the progression of myocardial inflammation, reduces collagen production, attenuates cardiac remodelling, and ameliorates cardiac function. In this review, we summarize recent progress in research on galectin-3 as a regulatory molecule involved in cardiovascular fibrosis in HF and its potential role in the diagnosis, risk assessment and treatment of cardiovascular diseases.

Protein kinase C promotes cardiac fibrosis and heart failure by modulating galectin-3 expression.

Protein kinase C (PKC) and galectin-3 are two important mediators that play a key pathogenic role in cardiac hypertrophy and heart failure (HF). However, the molecular mechanisms and signaling pathways are not fully understood. In this study, we explored the relationship between and roles of PKC-α and galectin-3 in the development of HF. We found that activation of PKC by phorbol dibutyrate (PDB) increased galectin-3 expression by ~180%, as well as collagen I and fibronection accumulation in cultured HL-1 cardiomyocytes. Over-expression of galectin-3 in HL-1 cells increased collagen I protein production. Inhibition of galectin-3 by ß-lactose blocked PDB-induced galectin-3 and collagen production, indicating that galectin-3 mediates PKC-induced cardiac fibrosis. In rats subjected to pulmonary artery banding (PAB) to induce right ventricular HF, galectin-3 was increased by ~140% in the right ventricle and also by ~240% in left ventricle compared to control. The elevated galectin-3 is consistent with an increase of total and activated (phosphorylated) PKC-α, α-SMA and collagen I. Finally, we extended our findings to examine the role of angiotensin II (Ang II), which activates the PKC pathway and contributes to cardiac fibrosis and the development of HF. We found that Ang II activated the PKC-α pathway and increased galectin-3 expression and collagen production. This study provides a new insight into the molecular mechanisms of HF mediated by PKC-α and galectin-3. PKC-α promotes cardiac fibrosis and HF by stimulation of galectin-3 expression.

Modulation of kidney urea transporter UT-A3 activity by alpha2,6-sialylation.

Two urea transporters, UT-A1 and UT-A3, are expressed in the kidney terminal inner medullary collecting duct (IMCD) and are important for the production of concentrated urine. UT-A1, as the largest isoform of all UT-A urea transporters, has gained much attention and been extensively studied; however, the role and the regulation of UT-A3 are less explored. In this study, we investigated UT-A3 regulation by glycosylation modification. A site-directed mutagenesis verified a single glycosylation site in UT-A3 at Asn279. Loss of the glycosylation reduced forskolin-stimulated UT-A3 cell membrane expression and urea transport activity. UT-A3 has two glycosylation forms, 45 and 65 kDa. Using sugar-specific binding lectins, the UT-A3 glycosylation profile was examined. The 45-kDa form was pulled down by lectin concanavalin A (Con A) and Galant husnivalis lectin (GNL), indicating an immature glycan with a high amount of mannose (Man), whereas the 65-kDa form is a mature glycan composed of acetylglucosamine (GlcNAc) and poly-N-acetyllactosame (poly-LacNAc) that was pulled down by wheat germ agglutinin (WGA) and tomato lectin, respectively. Interestingly, the mature form of UT-A3 glycan contains significant amounts of sialic acid. We explored the enzymes responsible for directing UT-A3 sialylation. Sialyltransferase ST6GalI, but not ST3GalIV, catabolizes UT-A3 α2,6-sialylation. Activation of protein kinase C (PKC) by PDB treatment promoted UT-A3 glycan sialylation and membrane surface expression. The PKC inhibitor chelerythrine blocks ST6GalI-induced UT-A3 sialylation. Increased sialylation by ST6GalI increased UT-A3 protein stability and urea transport activity. Collectively, our study reveals a novel mechanism of UT-A3 regulation by ST6GalI-mediated sialylation modification that may play an important role in kidney urea reabsorption and the urinary concentrating mechanism.

Activation of protein kinase C-α and Src kinase increases urea transporter A1 α-2, 6 sialylation.

The urea transporter A1 (UT-A1) is a glycosylated protein with two glycoforms: 117 and 97 kD. In diabetes, the increased abundance of the heavily glycosylated 117-kD UT-A1 corresponds to an increase of kidney tubule urea permeability. We previously reported that diabetes not only causes an increase of UT-A1 protein abundance but also, results in UT-A1 glycan changes, including an increase of sialic acid content. Because activation of the diacylglycerol (DAG)-protein kinase C (PKC) pathway is elevated in diabetes and PKC-α regulates UT-A1 urea transport activity, we explored the role of PKC in UT-A1 glycan sialylation. We found that activation of PKC specifically promotes UT-A1 glycan sialylation in both UT-A1-MDCK cells and rat kidney inner medullary collecting duct suspensions, and inhibition of PKC activity blocks high glucose-induced UT-A1 sialylation. Overexpression of PKC-α promoted UT-A1 sialylation and membrane surface expression. Conversely, PKC-α-deficient mice had significantly less sialylated UT-A1 compared with wild-type mice. Furthermore, the effect of PKC-α-induced UT-A1 sialylation was mainly mediated by Src kinase but not Raf-1 kinase. Functionally, increased UT-A1 sialylation corresponded with enhanced urea transport activity. Thus, our results reveal a novel mechanism by which PKC regulates UT-A1 function by increasing glycan sialylation through Src kinase pathways, which may have an important role in preventing the osmotic diuresis caused by glucosuria under diabetic conditions.

Lovastatin-Induced Phosphatidylinositol-4-Phosphate 5-Kinase Diffusion from Microvilli Stimulates ROMK Channels.

We recently showed that lovastatin attenuates cyclosporin A (CsA)-induced damage of cortical collecting duct (CCD) principal cells by reducing intracellular cholesterol. Previous studies showed that, in cell expression models or artificial membranes, exogenous cholesterol directly inhibits inward rectifier potassium channels, including Kir1.1 (Kcnj1; the gene locus for renal outer medullary K(+) [ROMK1] channels). Therefore, we hypothesized that lovastatin might stimulate ROMK1 by reducing cholesterol in CCD cells. Western blots showed that mpkCCDc14 cells express ROMK1 channels with molecular masses that approximate the molecular masses of ROMK1 in renal tubules detected before and after treatment with DTT. Confocal microscopy showed that ROMK1 channels were not in the microvilli, where cholesterol-rich lipid rafts are located, but rather, the planar regions of the apical membrane of mpkCCDc14 cells. Furthermore, phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2], an activator of ROMK channels, was detected mainly in the microvilli under resting conditions along with the kinase responsible for PI(4,5)P2 synthesis, phosphatidylinositol-4-phosphate 5-kinase, type I γ [PI(4)P5K I γ], which may explain the low basal open probability and increased sensitivity to tetraethylammonium observed here for this channel. Notably, lovastatin induced PI(4)P5K I γ diffusion into planar regions and elevated PI(4,5)P2 and ROMK1 open probability in these regions through a cholesterol-associated mechanism. However, exogenous cholesterol alone did not induce these effects. These results suggest that lovastatin stimulates ROMK1 channels, at least in part, by inducing PI(4,5)P2 synthesis in planar regions of the renal CCD cell apical membrane, suggesting that lovastatin could reduce cyclosporin-induced nephropathy and associated hyperkalemia.

Downregulation of urea transporter UT-A1 activity by 14-3-3 protein.

Urea transporter (UT)-A1 in the kidney inner medulla plays a critical role in the urinary concentrating mechanism and thereby in the regulation of water balance. The 14-3-3 proteins are a family of seven isoforms. They are multifunctional regulatory proteins that mainly bind to phosphorylated serine/threonine residues in target proteins. In the present study, we found that all seven 14-3-3 isoforms were detected in the kidney inner medulla. However, only the 14-3-3 γ-isoform was specifically and highly associated with UT-A1, as demonstrated by a glutathione-S-transferase-14-3-3 pulldown assay. The cAMP/adenylyl cyclase stimulator forskolin significantly enhanced their binding. Coinjection of 14-3-3γ cRNA into oocytes resulted in a decrease of UT-A1 function. In addition, 14-3-3γ increased UT-A1 ubiquitination and protein degradation. 14-3-3γ can interact with both UT-A1 and mouse double minute 2, the E3 ubiquitin ligase for UT-A1. Thus, activation of cAMP/PKA increases 14-3-3γ interactions with UT-A1 and stimulates mouse double minute 2-mediated UT-A1 ubiquitination and degradation, thereby forming a novel regulatory mechanism of urea transport activity.

Intratumoral estrogen sulfotransferase induction contributes to the anti-breast cancer effects of the dithiocarbamate derivative TM208.

AIM: Sulfotransferase-catalyzed sulfation is the most important pathway for inactivating estrogens. Thus, activation of estrogen sulfotransferase (EST) may be an alternative approach for the treatment of estrogen-dependent breast cancer. In this study we investigated the involvement of EST in anti-breast cancer effects of the dithiocarbamate derivative TM208 in vitro and in vivo. METHODS: The viability of human breast cancer MCF-7 cells was determined using a SBB assay. Nude mice bearing MCF-7 cells were orally administered TM208 (50 and 150 mg·kg(-1)·d(-1)) for 18 days. The xenograft tumors and uteri were collected. The mRNA expression of EST was examined with real-time PCR. EST protein was detected with Western blot, ELISA or immunohistochemical staining assays. A radioactive assay was used to measure the EST activity. Uterotropic bioassay was used to examine the uterine estrogen responses. RESULTS: Treatment with TM208 (10, 15 and 20 µmol/L) concentration-dependently increased EST expression in MCF-7 cells in vitro. Co-treatment with triclosan, an inhibitor of sulfonation, abolished TM208-induced cytotoxicity in MCF-7 cells. TM208 exhibited an apparent anti-estrogenic property: it exerted more potent cytotoxicity in E2-treated MCF-7 cells. In the nude mice bearing MCF-7 cells, TM208 administration time-dependently increased the expression and activity of EST, and blocked the gradual increase of E2 concentration in the xenograft tumors. Furthermore, TM208 administration blocked the estrogens-stimulated uterine enlargement. Tamoxifen, a positive control drug, produced similar effects on the expression and activity of EST in vitro and in vivo. CONCLUSION: The induction of EST and reduction of estrogen concentration contribute to the anti-breast cancer action of TM208 and tamoxifen. TM208 may be developed as anticancer drug for the treatment of estrogen receptor-positive breast cancer.

Biochemical properties of urea transporters.

Urea and urea transporters (UT) are critical to the production of concentrated urine and hence in maintaining body fluid balance. The UT-A1 urea transporter is the major and most important UT isoform in the kidney. Native UT-A1, expressed in the terminal inner medullary collecting duct (IMCD) epithelial cells, is a glycosylated protein with two glycoforms of 117 and 97 kDa. Vasopressin is the major hormone in vivo that rapidly increases urea permeability in the IMCD through increases in phosphorylation and apical plasma-membrane accumulation of UT-A1. The cell signaling pathway for vasopressin-mediated UT-A1 phosphorylation and activity involves two cAMP-dependent signaling pathways: protein kinase A (PKA) and exchange protein activated by cAMP (Epac). In this chapter, we will discuss UT-A1 regulation by phosphorylation, ubiquitination, and glycosylation.

Small GTPase Rab14 down-regulates UT-A1 urea transport activity through enhanced clathrin-dependent endocytosis.

The UT-A1 urea transporter plays an important role in the urinary concentration mechanism. However, the molecular mechanisms regarding UT-A1 trafficking, endocytosis, and degradation are still unclear. In this study, we identified the small GTPase Rab14 as a binding partner to the C terminus of UT-A1 in a yeast 2-hybrid assay. Interestingly, UT-A1 binding is preferential for the GDP-bound inactive form of Rab14. Coinjection of Rab14 in Xenopus oocytes results in a decrease of UT-A1 urea transport activity, suggesting that Rab14 acts as a negative regulator of UT-A1. We subsequently found that Rab14 reduces the cell membrane expression of UT-A1, as evidenced by cell surface biotinylation. This effect is blocked by chlorpromazine, an inhibitor of the clathrin-mediated endocytic pathway, but not by filipin, an inhibitor of the caveolin-mediated endocytic pathway. In kidney, Rab14 is mainly expressed in IMCD epithelial cells with a pattern identical to UT-A1 expression. Consistent with its role in participating in clathrin-mediated endocytosis, Rab14 localizes in nonlipid raft microdomains and codistributes with Rab5, a marker of the clathrin-mediated endocytic pathway. Taken together, our study suggests that Rab14, as a novel UT-A1 partner, may have an important regulatory function for UT-A1 urea transport activity in the kidney inner medulla.

Estrogen-related receptor ERRα regulation of human hydroxysteroid sulfotransferase (SULT2A1) gene expression in human Caco-2 cells.

Human hydroxysteroid sulfotransferase, SULT2A1, is important for xenobiotic detoxification and the maintenance of hydroxysteroid homeostasis. Our published report suggested that estrogen-related receptor ERRα downregulates SULT2A1 in Hep G2 cells. The results shown in this study suggest that ERRα upregulates SULT2A1 transcription in Caco-2 cells. The deletion analysis suggested that SULT2A1 promoter region between -65 and -44 is important for this upregulation. Our further investigation suggested that ERRα binding element, ERRE51, mediates ERRα activation of SULT2A1 promoter transcription in Caco-2 cells. The interaction of ERRE51 with ERRα was confirmed by electrophoretic mobility shift assay and chromatin immunoprecipitation analysis. Results also suggest that the difference of constitutive androstane receptor transcription levels in Hep G2 and Caco-2 cells at least partially contribute to the cell type dependent ERRα modulation of SULT2A1 promoter transcription. ERRα regulates human SULT2A1 transcription by competing with other nuclear receptors binding to the DNA-promoter region.

Dopamine D1 receptor activation induces dehydroepiandrosterone sulfotransferase (SULT2A1) in HepG2 cells.

AIM: Dopamine receptors are present in the nervous system and also widely distributed in the periphery. The aim of this study was to investigate the role of D1 subtype dopamine receptors (DRD1) in the regulation of dehydroepiandrosterone sulfotransferase (SULT2A1) in HepG2 cells. METHODS: HepG2 cells were treated with DRD1 agonists with or without DRD1 antagonist for 9 d. DRD1 and SULT2A1 mRNA expression, protein expression, and SULT2A1 activity were detected using RT-PCR, Western blotting and HPLC, respectively. The level of cAMP was measured using a commercial kit. RESULTS: All the 5 DR subtypes (DRD1-DRD5) were found to be expressed in HepG2 cells. Treatment of HepG2 cells with the specific DRD1 agonists SKF82958 (2.5 µmol/L) or SKF38393 (5 and 50 µmol/L) significantly increased the mRNA and protein expression of both DRD1 and SULT2A1, and increased SULT2A1 activity and cAMP levels. These effects were partially blocked by co-treatment with the specific DRD1 antagonist SCH23390 (2.5 µmol/L). In addition, transfection of HepG2 cells with DRD1-specific siRNAs decreased DRD1 mRNA expression by 40%, which resulted in the reduction of SULT2A1 mRNA expression by 60%, protein expression by 40%, and enzyme activity by 20%. CONCLUSION: DRD1 activation upregulates DRD1 and SULT2A1 expression and SULT2A1 activity in HepG2 cells, suggesting that the DRD1 subtype may be involved in the metabolism of drugs and xenobiotics through regulating SULT2A1.