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Luo J, Hu S, Fu M, Luo L, Li Y, Li W, Cai Y, Dong R, Yang Y, Tu L, Xu X. Inhibition of soluble epoxide hydrolase alleviates insulin resistance and hypertension via downregulation of SGLT2 in the mouse kidney. J Biol Chem 2021; 296:100667. [PMID: 33864813 PMCID: PMC8131320 DOI: 10.1016/j.jbc.2021.100667] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 04/07/2021] [Accepted: 04/13/2021] [Indexed: 12/09/2022] Open
Abstract
The epoxyeicosatrienoic acid (EET) exerts beneficial effects on insulin resistance and/or hypertension. EETs could be readily converted to less biological active diols by soluble epoxide hydrolase (sEH). However, whether sEH inhibition can ameliorate the comorbidities of insulin resistance and hypertension and the underlying mechanisms of this relationship are unclear. In this study, C57BL/6 mice were rendered hypertensive and insulin resistant through a high-fat and high-salt (HF–HS) diet. The sEH inhibitor, 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), was used to treat mice (1 mg/kg/day) for 8 weeks, followed by analysis of metabolic parameters. The expression of sEH and the sodium–glucose cotransporter 2 (SGLT2) was markedly upregulated in the kidneys of mice fed an HF–HS diet. We found that TPPU administration increased kidney EET levels, improved insulin resistance, and reduced hypertension. Furthermore, TPPU treatment prevented upregulation of SGLT2 and the associated increased urine volume and the excretion of urine glucose and urine sodium. Importantly, TPPU alleviated renal inflammation. In vitro, human renal proximal tubule epithelial cells (HK-2 cells) were used to further investigate the underlying mechanism. We observed that 14,15-EET or sEH knockdown or inhibition prevented the upregulation of SGLT2 upon treatment with palmitic acid or NaCl by inhibiting the inhibitory kappa B kinase α/β/NF-κB signaling pathway. In conclusion, sEH inhibition by TPPU alleviated insulin resistance and hypertension induced by an HF–HS diet in mice. The increased urine excretion of glucose and sodium was mediated by decreased renal SGLT2 expression because of inactivation of the inhibitory kappa B kinase α/β/NF-κB–induced inflammatory response.
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Affiliation(s)
- Jinlan Luo
- Department of Geriatric Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Division of Cardiology and Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shuiqing Hu
- Division of Cardiology and Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Menglu Fu
- Department of Geriatric Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Liman Luo
- Department of Geriatric Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuanyuan Li
- Department of Geriatric Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wenhua Li
- Department of Geriatric Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yueting Cai
- Division of Cardiology and Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ruolan Dong
- Institute of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Yang
- Division of Endocrinology and Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ling Tu
- Department of Geriatric Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, China.
| | - Xizhen Xu
- Division of Cardiology and Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, China.
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Monteiro MB, Thieme K, Santos-Bezerra DP, Queiroz MS, Woronik V, Passarelli M, Machado UF, Giannella-Neto D, Oliveira-Souza M, Corrêa-Giannella ML. Beta-2-microglobulin (B2M) expression in the urinary sediment correlates with clinical markers of kidney disease in patients with type 1 diabetes. Metabolism 2016; 65:816-24. [PMID: 27173460 DOI: 10.1016/j.metabol.2016.02.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/01/2016] [Accepted: 02/22/2016] [Indexed: 11/17/2022]
Abstract
PURPOSE After observing variation in the expression of the housekeeping gene B2M in cells of the urinary sediment during a study of candidate genes potentially involved in diabetic kidney disease (DKD), we hypothesized that B2M mRNA expression in the urinary sediment could reflect the presence of DKD. METHODS qPCR was used to quantify B2M mRNA expression in cells of the urinary sediment of 51 type 1 diabetes (T1D) patients (61% women, 33.5 [27.0-39.7] years old, with diabetes duration of 21.0 [15.0-28.0] years and HbA1c of 8.2% [7.3-8.9]; median [interquartile interval]) sorted according to the diabetic nephropathy (DN) stages; 8 focal segmental glomerulosclerosis (FSGS) patients and 10 healthy controls. B2M mRNA expression was also evaluated in human embryonic kidney epithelium-like (HEK-293) cells exposed to 25mM glucose and to albumin in order to mimic, respectively, a diabetic and a proteinuric milieu. RESULTS No differences were found in B2M mRNA expression among healthy controls, FSGS and T1D patients. Nonetheless B2M mRNA expression was higher in the group composed by T1D patients with incipient or overt DN combined with FSGS patients versus T1D patients without DN combined with healthy controls (P=0.0007). B2M mRNA expression was higher in T1D patients with incipient or overt DN versus without DN (P=0.03). B2M mRNA expression positively correlated with albuminuria in the overall T1D population (r=0.43; P=0.01) and negatively correlated with estimated glomerular filtration rate in male T1D patients (r=- 0.57; P=0.01). Increased B2M expression was observed in HEK-293 cells exposed to 25mM glucose and to albumin. CONCLUSIONS Β2M mRNA expression in cells of the urinary sediment is higher in T1D patients with DKD and in patients with FSGS in comparison to healthy subjects, maybe reflecting a tubulointerstitial injury promoted by albumin. Given the proinflammatory nature of B2M, we suggest that this protein contributes to diabetic (and possibly, to non-diabetic) tubulopathy.
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Affiliation(s)
- Maria Beatriz Monteiro
- Laboratory of Cellular and Molecular Endocrinology (LIM-25), University of São Paulo Medical School, Av. Dr. Arnaldo 455 #4305, 01246-903, São Paulo.
| | - Karina Thieme
- Endocrine Division, Hospital das Clínicas, University of São Paulo Medical School, Av. Dr. Enéas de Carvalho Aguiar 155, 05403-000, São Paulo.
| | - Daniele Pereira Santos-Bezerra
- Laboratory of Cellular and Molecular Endocrinology (LIM-25), University of São Paulo Medical School, Av. Dr. Arnaldo 455 #4305, 01246-903, São Paulo.
| | - Márcia Silva Queiroz
- Lipids Laboratory (LIM-10), University of São Paulo Medical School, Av. Dr. Arnaldo 455 #3305, 01246-903, São Paulo.
| | - Viktoria Woronik
- Laboratory of Renal Pathophysiology (LIM-16), University of São Paulo Medical School, Av. Dr. Arnaldo 455 #3345, 01246-903, São Paulo.
| | - Marisa Passarelli
- Lipids Laboratory (LIM-10), University of São Paulo Medical School, Av. Dr. Arnaldo 455 #3305, 01246-903, São Paulo.
| | - Ubiratan Fabres Machado
- Laboratory of Metabolism and Endocrinology, Department of Physiology and Biophysics, Biomedical Sciences Institute, Av. Prof. Lineu Prestes 1524 #126, 05508-000, São Paulo.
| | - Daniel Giannella-Neto
- Programa de Pós-Graduação em Medicina, Universidade Nove de Julho - UNINOVE, R. Vergueiro, 235/249, 01504-001, São Paulo.
| | - Maria Oliveira-Souza
- Laboratory of Renal Physiology, Department of Physiology and Biophysics, Biomedical Sciences Institute, Av. Prof. Lineu Prestes 1524 #227, 05508-000, São Paulo.
| | - Maria Lúcia Corrêa-Giannella
- Laboratory of Cellular and Molecular Endocrinology (LIM-25), University of São Paulo Medical School, Av. Dr. Arnaldo 455 #4305, 01246-903, São Paulo; Laboratory of Cellular and Molecular Endocrinology (LIM-25), Cell and Molecular Therapy Center (NUCEL), University of São Paulo Medical School, R. Pangaré, 05360-120, São Paulo.
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Liu D, Xu M, Ding LH, Lv LL, Liu H, Ma KL, Zhang AH, Crowley SD, Liu BC. Activation of the Nlrp3 inflammasome by mitochondrial reactive oxygen species: a novel mechanism of albumin-induced tubulointerstitial inflammation. Int J Biochem Cell Biol 2014; 57:7-19. [PMID: 25281528 DOI: 10.1016/j.biocel.2014.09.018] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/30/2014] [Accepted: 09/16/2014] [Indexed: 01/22/2023]
Abstract
Albuminuria is not only an important marker of chronic kidney disease but also a crucial contributor to tubulointerstitial inflammation (TIF). In this study, we determined whether activation of the Nlrp3 inflammasome is involved in albuminuria induced-TIF and the underlying mechanisms of inflammasome activation by mitochondrial reactive oxygen species (mROS). We established an albumin-overload induced rat nephropathy model characterised by albuminuria, renal infiltration of inflammatory cells, tubular dilation and atrophy. The renal expression levels of the Nlrp3 inflammasome, IL-1β and IL-18 were significantly increased in this animal model. In vitro, albumin time- and dose-dependently increased the expression levels of the Nlrp3 inflammasome, IL-1β and IL18. Moreover, the silencing of the Nlrp3 gene or the use of the caspase-1 inhibitor Z-VAD-fmk significantly attenuated the albumin-induced increase in IL-1β and IL-18 expression in HK2 cells. In addition, mROS generation was elevated by albumin stimulation, whereas the ROS scavenger N-acetyl-l-cysteine (NAC) inhibited Nlrp3 expression and the release of IL-1β and IL-18. In kidney biopsy specimens obtained from patients with IgA nephropathy, Nlrp3 expression was localised to the proximal tubular epithelial cells, and this result is closely correlated with the extent of proteinuria and TIF. In summary, this study demonstrates that albuminuria may serve as an endogenous danger-associated molecular pattern (DAMP) that stimulates TIF via the mROS-mediated activation of the cytoplasmic Nlrp3 inflammasome.
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Affiliation(s)
- Dan Liu
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Min Xu
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Li-Hong Ding
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Lin-Li Lv
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Hong Liu
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Kun-Ling Ma
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China
| | - Ai-Hua Zhang
- Institute of Pediatrics, Department of Nephrology, Nanjing Children's Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Steven D Crowley
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC, United States
| | - Bi-Cheng Liu
- Institute of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu, China.
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The immunomodulatory effects of albumin in vitro and in vivo. Adv Pharmacol Sci 2011; 2011:691928. [PMID: 21603190 PMCID: PMC3096151 DOI: 10.1155/2011/691928] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 02/17/2011] [Accepted: 02/23/2011] [Indexed: 12/18/2022] Open
Abstract
Albumin appears to have proinflammatory effects in vitro. We hypothesized that albumin would induce a state of tolerance to subsequent administration of lipopolysaccharide (LPS) in vitro and in vivo. RAW264.7 and primary peritoneal macrophages were treated with increasing doses of bovine serum albumin (BSA) and harvested for NF-κB luciferase reporter assay or TNF-α ELISA. In separate experiments, RAW264.7 cells were preconditioned with 1 mg/mL BSA for 18 h prior to LPS (10 μg/mL) treatment and harvested for NF-κB luciferase reporter assay or TNF-α ELISA. Finally, C57Bl/6 mice were preconditioned with albumin via intraperitoneal administration 18 h prior to a lethal dose of LPS (60 mg/kg body wt). Blood was collected at 6 h after LPS administration for TNF-α ELISA. Albumin produced a dose-dependent and TLR-4-dependent increase in NF-κB activation and TNF-α gene expression in vitro. Albumin preconditioning abrogated the LPS-mediated increase in NF-κB activation and TNF-α gene expression in vitro and in vivo. The clinical significance of these findings remains to be elucidated.
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Lee YJ, Suh HN, Han HJ. Effect of BSA-induced ER stress on SGLT protein expression levels and α-MG uptake in renal proximal tubule cells. Am J Physiol Renal Physiol 2009; 296:F1405-16. [DOI: 10.1152/ajprenal.90652.2008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Recent studies demonstrated that endoplasmic reticulum (ER) stress regulates glucose homeostasis and that ER stress preconditioning which induces an adaptive, protective unfolded protein response (UPR) offers cytoprotection against nephrotoxins. Thus the aim of the present study was to use renal proximal tubule cells (PTCs) to further elucidate the link between the BSA-induced ER stress and α-methyl-d-glucopyranoside (α-MG) uptake and to identify related signaling pathways. Among ER stress inducers such as high glucose, BSA, H2O2, or tumicamycin, BSA pretreatment ameliorated the reduction of Na+-glucose cotransporter (SGLT) expression and α-MG uptake by gentamicin or cyclosporine A. Immunofluorescence studies revealed that BSA (10 mg/ml) stimulated the expression of glucose-regulated protein 78 (GRP78), an ER stress biomarker. In addition, BSA increased levels of GRP78 protein expression and eukaryotic initiation factor 2α (eIF2α) phosphorylation in a time-dependent manner. Furthermore, transfection with a GRP78-specific small interfering RNA (siRNA) inhibited BSA-stimulated SGLT expression and α-MG uptake. In experiments designed to unravel the mechanisms underlying BSA-induced ER stress, BSA stimulated the production of cellular reactive oxygen species (ROS), and antioxidants such as ascorbic acid or N-acetylcysteine (NAC) blocked BSA-induced increases in GRP78 activation, eIF2α phosphorylation, SGLT expression, and α-MG uptake. Moreover, the cells upregulated peroxisome proliferator-activated receptor-γ (PPARγ) mRNA levels in response to BSA or troglitazone (a PPARγ agonist), but BSA was ineffective in the presence of GW9662 (a PPARγ antagonist). In addition, both BSA and troglitazone stimulated GRP78 and eIF2α activation, SGLT expression, and α-MG uptake, whereas GW9662 inhibited the effects of BSA. BSA also stimulated phosphorylation of JNK and NF-κB, and GW9662 or GRP78 siRNA attenuated this response. Moreover, SP600125 or SN50 effectively blocked SGLT expression and α-MG uptake in BSA- or PPARγ agonists (troglitazone or PGJ2)-treated PTCs. We conclude that BSA induces ER stress through ROS production and PPARγ activation, which subsequently activates JNK/NF-κB signaling to enhance glucose uptake in renal PTCs.
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Tabatabai NM, Sharma M, Blumenthal SS, Petering DH. Enhanced expressions of sodium-glucose cotransporters in the kidneys of diabetic Zucker rats. Diabetes Res Clin Pract 2009; 83:e27-30. [PMID: 19095325 PMCID: PMC2652566 DOI: 10.1016/j.diabres.2008.11.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 10/08/2008] [Accepted: 11/06/2008] [Indexed: 10/21/2022]
Abstract
Diabetes-mediated changes in mRNA expressions of kidney glucose transporters SGLT1 and SGLT2 were investigated in Zucker rats. SGLTs expressions in pre-diabetic obese rats were similar to leans. SGLT1 and SGLT2 levels in diabetic obese rats were 1.6 (P<0.03) and 4.8 (P<0.002) folds higher than age-matched leans, respectively.
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Affiliation(s)
- Niloofar M Tabatabai
- Division of Endocrinology, Metabolism and Clinical Nutrition, Medical College of Wisconsin, Milwaukee, WI 53226-0509, USA.
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Lee YJ, Han HJ. Albumin-stimulated DNA synthesis is mediated by Ca2+/PKC as well as EGF receptor-dependent p44/42 MAPK and NF-κB signal pathways in renal proximal tubule cells. Am J Physiol Renal Physiol 2008; 294:F534-41. [DOI: 10.1152/ajprenal.00408.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is now recognized that significant tubular reabsorption of albumin occurs under physiological conditions that may play an important role in maintaining proximal tubular integrity and function. Therefore, this study examined the effect of bovine serum albumin (BSA) on DNA synthesis and its related signal molecules in primary cultured rabbit renal proximal tubule cells (PTCs). BSA increased the level of [3H]thymidine incorporation in a dose (≥3 mg/ml)- and time (≥3 h)-dependent manner, intracellular Ca2+concentration, and the level of protein kinase C (PKC) phosphorylation and stimulated the phosphorylation of the epidermal growth factor receptor (EGFR), which was inhibited by EGTA (extracellular Ca2+chelator), 1,2-bis(2-aminophenoxy)ethane- N,N,N′,N′-tetraacetic acid acetoxymethyl ester (BAPTA-AM, intracellular Ca2+chelator), or PKC inhibitors (staurosporine or bisindolylmaleimide I). In addition, the PKC inhibitors or an EGFR inhibitor (AG-1478) blocked the BSA-induced phosphorylation of p44/42 mitogen-activated protein kinases (MAPKs). BSA also increased the level of nuclear factor-κB (NF-κB) and inhibitor of NF-κB (IκB) phosphorylation, which was blocked by staurosporine, AG-1478, or PD-98059 (p44/42 MAPK inhibitor). Inhibition of Ca2+, PKC, EGFR, p44/42 MAPK, or NF-κB signal pathways blocked the BSA-induced incorporation of [3H]thymidine. Consequently, the inhibition of Ca2+, PKC, EGFR, p44/42 MAPKs, or NF-κB blocked the BSA-induced increases in cyclin D1, cyclin-dependent kinase (CDK)4, cyclin E, or CDK2 and restored the BSA-induced inhibition of p21WAF/Cip1and p27Kip1expression. In conclusion, BSA stimulates DNA synthesis that is mediated by Ca2+/PKC as well as the EGFR-dependent p44/42 MAPK and NF-κB signal pathways in PTCs.
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Lee GS, Choi KC, Han HJ, Jeung EB. The classical and a non-classical pathways associated with NF-kappaB are involved in estrogen-mediated regulation of calbindin-D9k gene in rat pituitary cells. Mol Cell Endocrinol 2007; 277:42-50. [PMID: 17825480 DOI: 10.1016/j.mce.2007.07.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 07/05/2007] [Accepted: 07/27/2007] [Indexed: 12/29/2022]
Abstract
Calbindin-D9k (CaBP-9k) is a high affinity calcium binding protein that is highly expressed in the duodenum, kidney, uterus, and pituitary glands. Previous studies have shown that CaBP-9k expression is regulated by several steroid hormones, such as 1,25-dihydroxyvitamin D3, glucocorticoids, 17beta-estradiol (E2), and progesterone (P4), in a tissue-specific manner. However, the promoter elements that mediate transcriptional regulation by these steroid hormones are not clearly understood, mainly due to the lack of an appropriate cell line expressing CaBP-9k. Recently it was shown that CaBP-9k was constitutively expressed in the rat pituitary gland, and is expressed in an E2-dependent manner in a pituitary gland tumor-derived cell line, GH3. In the current study, we examined the activity of the estrogen responsive element (ERE) in rat CaBP-9k gene in GH3 cells, using a luciferase gene reporter assay, electrophoretic mobility shift assay, and mutagenesis. A nuclear factor-kappaB (NF-kappaB) binding site in the CaBP-9k promoter region was identified (nucleotides -848 to -834 from the transcriptional start site), and we demonstrated that addition of an NF-kappaB blocker to GH3 cells reduced E2-induced CaBP-9k transcription. In the present study, we further showed a previously reported imperfect ERE (nucleotides +51 to +65) between exon I and intron A of CaBP-9k, indicating that the interaction of estrogen receptor (ER) alpha with this region is involved in the regulation of CaBP-9k promoter activity and its expression. Taken together, these results suggest that in GH3 cells, both the classical ERalpha-ERE pathway and a non-classical pathway involving NF-kappaB are involved in E2-mediatd regulation of CaBP-9k expression in the pituitary gland.
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Affiliation(s)
- Geun-Shik Lee
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea
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Lee YJ, Heo JS, Suh HN, Lee MY, Han HJ. Interleukin-6 stimulates alpha-MG uptake in renal proximal tubule cells: involvement of STAT3, PI3K/Akt, MAPKs, and NF-kappaB. Am J Physiol Renal Physiol 2007; 293:F1036-46. [PMID: 17581928 DOI: 10.1152/ajprenal.00034.2007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Recent studies have shown that interleukin 6 (IL-6) acts on the cellular proliferation-activating transduction signals during cellular regeneration. Therefore, this study examined the effect of IL-6 on the activation of Na(+)/glucose cotransporters (SGLTs) and its related signaling pathways in primary cultured renal proximal tubule cells (PTCs). IL-6 increased the level of alpha-methyl-d-[(14)C]glucopyranoside (alpha-MG) uptake in time- and dose-dependent manners. IL-6 also increased SGLT1 plus SGLT2 mRNA and protein expression level. The IL-6 receptors (IL-6Ralpha and gp 130) were expressed in PTCs. In addition, genistein and herbimycin A completely blocked the IL-6-induced increases in alpha-MG uptake and the protein expression level of SGLTs. On the other hand, IL-6 increased the level of 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate-sensitive cellular reactive oxygen species (ROS), and IL-6-induced increases in alpha-MG uptake and the protein expression level of SGLTs were blocked by ascorbic acid or taurine (antioxidants). IL-6 also increased the phosphorylation of signal transducer and activator of transcription-3 (STAT3), phosphoinositide-3 kinase (PI3K)/Akt, and mitogen-activated protein kinases (MAPKs) in a time-dependent manner. A pretreatment with STAT3 inhibitor LY 294002, an Akt inhibitor, or MAPK inhibitors significantly blocked the IL-6-induced increase in alpha-MG uptake. In addition, IL-6 increased the level of nuclear factor-kappaB (NF-kappaB) phosphorylation. A pretreatment with SN50 or BAY 11-7082 also blocked the IL-6-induced increase in alpha-MG uptake. In conclusion, IL-6 increases the SGLT activity through ROS, and its action in renal PTCs is associated with the STAT3, PI3K/Akt, MAPKs, and NF-kappaB signaling pathways.
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Affiliation(s)
- Yu Jin Lee
- Department of Veterinary Physiology, Biotherapy Human Resources Center, College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
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Sherman H, Chapnik N, Froy O. Albumin and amino acids upregulate the expression of human beta-defensin 1. Mol Immunol 2006; 43:1617-23. [PMID: 16263169 DOI: 10.1016/j.molimm.2005.09.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Accepted: 09/24/2005] [Indexed: 01/24/2023]
Abstract
Antimicrobial peptides are essential components of the innate immune system and are the first line of defense against invading pathogens. Human beta-defensin 1 (hBD-1) is the most important antimicrobial peptide in human epithelia, its expression is constitutive in most tissues, and it is not induced in instances of infection or inflammation. In addition to its antibacterial activity, hBD-1 has an immunomodulatory activity by recruiting immune cells. Our objective was to determine whether immune-enhancing ingredients, such as arginine, isoleucine, and polyunsaturated fatty acids (PUFA), which are added to immune-enhancing formulas, mediate their beneficial activity by bolstering the immune system through hBD-1 induction. Real-time PCR analysis of hBD-1 in human colon cells, HCT-116, revealed upregulation after treatment with arginine, isoleucine, and bovine serum albumin (BSA). BSA increased transcription as well as secretion of hBD-1. hBD-1 upregulation in response to BSA treatment was concomitant with c-myc over-expression, suggesting that hBD-1 may be regulated via a non-inflammatory pathway involving c-myc. Assuming similar control in vivo, our results may imply that nutrients found in immune-enhancing formulas upregulate hBD-1 expression, which, in turn, recruits the adaptive immune system. This sequence of events bolsters of the immune system, which may lead to fewer infectious complications, less antibiotics usage, and a shorter hospital stay, as indeed has been shown in patients fed immune-enhancing formulas.
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Affiliation(s)
- Hadas Sherman
- Institute of Biochemistry, Food Science, and Nutrition, Faculty of Agriculture, Food, and Environmental Quality, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
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