scholarly journals Tumor necrosis factor-alpha impairs intestinal phosphate absorption in colitis

2009 ◽  
Vol 296 (4) ◽  
pp. G775-G781 ◽  
Author(s):  
Huacong Chen ◽  
Hua Xu ◽  
Jiali Dong ◽  
Jing Li ◽  
Fayez K. Ghishan
Keyword(s):  
Egf Receptor ◽  
Phosphate Transport ◽  
Luciferase Assay ◽  
Receptor Interaction ◽  
Mobility Shift ◽  
Necrosis Factor Alpha ◽  
Bone Disorders ◽  
Phosphate Absorption ◽  
Tnf Α ◽  
Intestinal Phosphate Absorption

Phosphate homeostasis is critical for many physiological functions. Up to 85% of phosphate is stored in bone and teeth. The remaining 15% is distributed in cells. Phosphate absorption across the brush-border membrane (BBM) of enterocytes occurs mainly via a sodium-dependent pathway, which is mediated by type IIb sodium-phosphate cotransporters (NaPi-IIb). Patients of inflammatory bowel diseases (IBDs) suffer not only from diarrhea and nutrient malabsorption but also from bone loss. About 31–59% of patients with IBD develop bone disorders. Since the intestine is a primary location for dietary phosphate absorption, it is logical to postulate that there is an inverse relationship between gastrointestinal disorders and phosphate transport, which, in turn, contributes to bone disorders observed in patients with IBD. Phosphate absorption and NaPi-IIb expression was studied with BBM vesicles isolated from trinitrobenzene sulphonic acid (TNBS) animals as well as in Caco-2 cells. The mechanism of TNF-α downregulation of NaPi-IIb expression was investigated by luciferase assay, gel mobility shift assay (GMSA), and coimmunoprecipitation. Intestinal phosphate absorption mediated by NaPi-IIb was reduced both in TNBS colitis and in TNF-α-treated cells. Transient transfection indicated that TNF-α inhibits NaPi-IIb expression by reducing NaPi-IIb basal promoter activity. GMSAs identified NF1 protein as an important factor in TNF-α-mediated NaPi-IIb downregulation. Signaling transduction study and coimmunoprecipitation suggested that TNF-α interacts with EGF receptor to activate ERK1/2 pathway. Intestinal phosphate absorption mediated by NaPi-IIb protein is reduced in colitis. This inhibition is mediated by the proinflammatory cytokine TNF-α through a novel molecular mechanism involving TNF-α/EGF receptor interaction.

Phosphate homeostasis and the renal-gastrointestinal axis

2010 ◽  
Vol 299 (2) ◽  
pp. F285-F296 ◽  
Author(s):  
Joanne Marks ◽  
Edward S. Debnam ◽  
Robert J. Unwin
Keyword(s):  
Small Intestine ◽  
Phosphate Transport ◽  
Phosphate Absorption ◽  
Renal Phosphate Reabsorption ◽  
Sodium Dependent ◽  
Dietary Phosphate ◽  
Intestinal Phosphate Absorption ◽  
End Stage ◽  
And Control ◽  
Renal Phosphate Excretion

Transport of phosphate across intestinal and renal epithelia is essential for normal phosphate balance, yet we know less about the mechanisms and regulation of intestinal phosphate absorption than we do about phosphate handling by the kidney. Recent studies have provided strong evidence that the sodium-phosphate cotransporter NaPi-IIb is responsible for sodium-dependent phosphate absorption by the small intestine, and it might be that this protein can link changes in dietary phosphate to altered renal phosphate excretion to maintain phosphate balance. Evidence is also emerging that specific regions of the small intestine adapt differently to acute or chronic changes in dietary phosphate load and that phosphatonins inhibit both renal and intestinal phosphate transport. This review summarizes our current understanding of the mechanisms and control of intestinal phosphate absorption and how it may be related to renal phosphate reabsorption; it also considers the ways in which the gut could be targeted to prevent, or limit, hyperphosphatemia in chronic and end-stage renal failure.

LncRNA KCNQ1OT1 ameliorates particle-induced osteolysis through inducing macrophage polarization by inhibiting miR-21a-5p

2018 ◽  
Vol 399 (4) ◽  
pp. 375-386 ◽  
Author(s):  
Xuren Gao ◽  
Jian Ge ◽  
Weiyi Li ◽  
Wangchen Zhou ◽  
Lei Xu
Keyword(s):  
Macrophage Polarization ◽  
Inos Expression ◽  
Luciferase Assay ◽  
M2 Macrophage ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Rna Immunoprecipitation ◽  
Raw264.7 Cell ◽  
Primary Bone ◽  
Oxide Synthase

AbstractThis study aimed to investigate the mechanism of lncRNA-KCNQ1OT1 on macrophage polarization to ameliorate particle-induced osteolysis. We used polymethylmethacrylate (PMMA) to induce primary bone marrow-derived macrophages (BMMs) obtained from mice and the RAW264.7 cell line, and found that the tumor necrosis factor-alpha (TNF-α) concentration and inducible nitric oxide synthase (iNOS) expression was increased, while interleukin (IL)-10 concentration and Arg1 expression were decreased in PMMA-induced cells. KCNQ1OT1 and IL-10 expression were both suppressed and miR-21a-5p expression was promoted in PMMA-induced cells. Overexpression of KCNQ1OT1 reversed the effect of PMMA on RAW264.7 cells, such as the reduced TNF-α concentration and iNOS expression, and increased IL-10 concentration and Arg1 expression in PMMA-induced cell transfected with pcDNA-KCNQ1OT1. The luciferase assay confirmed that IL-10 is a target of miR-21a-5p. RNA immunoprecipitation (RIP) and RNA pull-down experiments demonstrated that KCNQ1OT1 functions as a miR-21a-5p decoy. Thus, lncRNA KCNQ1OT1 induces M2 macrophage polarization to ameliorate particle-induced osteolysis by inhibiting miR-21a-5p.

Pro-inflammatory Cytokines in Acute Coronary Syndromes

2020 ◽  
Vol 26 (36) ◽  
pp. 4624-4647 ◽  
Author(s):  
Konstantinos Mourouzis ◽  
Evangelos Oikonomou ◽  
Gerasimos Siasos ◽  
Sotiris Tsalamadris ◽  
Georgia Vogiatzi ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Vulnerable Plaque ◽  
Treatment Strategies ◽  
Interferon Γ ◽  
Receptor Interaction ◽  
Necrosis Factor Alpha ◽  
Immune System Activation ◽  
Cardiovascular Prognosis ◽  
Tnf Α ◽  
Plaque Destabilization

Background: Over the last decades, the role of inflammation and immune system activation in the initiation and progression of coronary artery disease (CAD) has been established. Objectives: The study aimed to present the interplay between cytokines and their actions preceding and shortly after ACS. Methods: We searched in a systemic manner the most relevant articles to the topic of inflammation, cytokines, vulnerable plaque and myocardial infarction in MEDLINE, COCHRANE and EMBASE databases. Results: Different classes of cytokines (intereleukin [IL]-1 family, Tumor necrosis factor-alpha (TNF-α) family, chemokines, adipokines, interferons) are implicated in the entire process leading to destabilization of the atherosclerotic plaque, and consequently, to the incidence of myocardial infarction. Especially IL-1 and TNF-α family are involved in inflammatory cell accumulation, vulnerable plaque formation, platelet aggregation, cardiomyocyte apoptosis and adverse remodeling following the myocardial infarction. Several cytokines such as IL-6, adiponectin, interferon-γ, appear with significant prognostic value in ACS patients. Thus, research interest focuses on the modulation of inflammation in ACS to improve clinical outcomes. Conclusion: Understanding the unique characteristics that accompany each cytokine-cytokine receptor interaction could illuminate the signaling pathways involved in plaque destabilization and indicate future treatment strategies to improve cardiovascular prognosis in ACS patients.

scholarly journals Up-Regulation of Gamma Interferon Receptor Expression Due to Chlamydia-Toll-Like Receptor Interaction Does Not Enhance Signal Transducer and Activator of Transcription 1 Signaling

2006 ◽  
Vol 74 (12) ◽  
pp. 6877-6884 ◽  
Author(s):  
Kari Ann Shirey ◽  
Joo-Yong Jung ◽  
Joseph M. Carlin
Keyword(s):  
Adaptor Protein ◽  
Gamma Interferon ◽  
Chlamydia Psittaci ◽  
Receptor Expression ◽  
Receptor Interaction ◽  
Signal Transducer ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Infected Cells ◽  
Ifn Γ

ABSTRACT Gamma interferon (IFN-γ)-induced indoleamine dioxygenase (IDO), which inhibits chlamydial replication by reducing the availability of tryptophan, is up-regulated by interleukin-1β (IL-1β) and tumor necrosis factor alpha (TNF-α). The mechanisms by which this occurs include an increase in the synthesis of interferon regulatory factor-1 as well as a nuclear factor-κB (NF-κB)-dependent increase in the expression of IFN-γ receptors (IFN-γR). Although Chlamydia is susceptible to IDO, it up-regulates IFN-γR expression to a greater degree than either IL-1β or TNF-α, perhaps through interaction with Toll-like receptors (TLR). The purpose of this study was to determine the mechanism by which Chlamydia psittaci up-regulates IFN-γR expression and evaluate this effect on IDO induction. Infection of HEK 293 cells with C. psittaci increased IFN-γR expression only in cells expressing either TLR2 or TLR4 and the adaptor protein MD-2. In addition, up-regulation of IFN-γR expression in Chlamydia-infected HeLa cells could be blocked either by neutralizing TLRs with anti-TLR2 and/or anti-TLR4 or by inhibiting NF-κB transactivation with a proteasome inhibitor. Although the newly expressed IFN-γR in Chlamydia-infected cells were capable of binding IFN-γ, they did not enhance IFN-γ-induced IDO activity in a manner similar to those observed for IL-1β and TNF-α. Instead, IDO activation in Chlamydia-infected cells was no different than that induced in uninfected cells, despite the increase in IFN-γR expression. Furthermore, the amount of IFN-γ-induced signal transducer and activator of transcription 1 (STAT-1) activation in infected cells paralleled that observed in uninfected cells, suggesting that STAT-1 activation by these newly expressed receptors was impaired.

Effect of Chinese Herbal Monomer Hairy Calycosin on Nonalcoholic Fatty Liver Rats and its Mechanism

2019 ◽  
Vol 22 (3) ◽  
pp. 194-200 ◽  
Author(s):  
Xiang Liu ◽  
Zhi-Hong Xie ◽  
Chen-Yuan Liu ◽  
Ying Zhang
Keyword(s):  
Fatty Liver ◽  
Liver Tissue ◽  
Liver Homogenate ◽  
Control Group ◽  
Necrosis Factor Alpha ◽  
Alcoholic Fatty Liver ◽  
Nonalcoholic Fatty Liver ◽  
Chinese Herbal ◽  
Tnf Α ◽  
Model Control

Background: Chinese herbal monomer hairy Calycosin is a flavonoid extracted from Radix astragali. Aims and Scope: The aim of the research was to investigate the effect and mechanism of Hairy Calycosin on Non-Alcoholic Fatty Liver Dieases (NAFLD) in rats. Materials and Methods: 60 rats were randomly divided into 6 groups, then NAFLD rat models were prepared and treated with different doses of Hairy Calycosin (0.5, 1.0, 2.0 mg/kg) or Kathyle relatively. Results: Both 1.0 mg/kg and 2.0 mg/kg Hairy Calycosin treatment could significantly increase the serum Superoxide Dismutase (SOD) content of the model rats and reduce the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), Free Fatty Acid (FFA), IL-6, tumor necrosis factor-alpha (TNF-α) and liver homogenate malondialdehyde (MDA), while 2.0 mg/kg Hairy Calycosin can down-regulate liver tissue cytochrome p450 2E1 (CYP2E1). In the electron microscope, compared with the model control group, the mitochondrial swelling in the hepatocytes of Hairy Calycosin (1.0, 2.0 mg/kg) treatment group was significantly reduced, the ridge on the inner membrane of mitochondria increased, and the lipid droplets became much smaller. Conclusion: Hairy Calycosin can effectively control the lipid peroxidation in liver tissues of rats with NAFLD, and reduce the levels of serum TNF-α, IL-6, MDA and FFA, effectively improve the steatosis and inflammation of liver tissue, and down-regulate the expression of CYP2E1, inhibit apoptosis of hepatocytes.

Regulation of microRNAs in Inflammation-Associated Colorectal Cancer: A Mechanistic Approach

2020 ◽  
Vol 20 ◽  
Author(s):  
Sridhar Muthusami ◽  
Ilangovan Ramachandran ◽  
Sneha Krishnamoorthy ◽  
Yuvaraj Sambandam ◽  
Satish Ramalingam ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Molecular Mechanisms ◽  
Colorectal Carcinogenesis ◽  
Model Systems ◽  
Necrosis Factor Alpha ◽  
Multi Stage ◽  
Mechanistic Approach ◽  
Tnf Α ◽  
Factor Alpha

: The development of colorectal cancer (CRC) is a multi-stage process. The inflammation of the colon as in inflammatory bowel disease (IBD) such as ulcerative colitis (UC) or Crohn’s disease (CD) is often regarded as the initial trigger for the development of CRC. Many cytokines such as tumor necrosis factor alpha (TNF-α) and several interleukins (ILs) are known to exert proinflammatory actions, and inflammation initiates or promotes tumorigenesis of various cancers, including CRC through differential regulation of microRNAs (miRNAs/miRs). miRNAs can be oncogenic miRNAs (oncomiRs) or anti-oncomiRs/tumor suppressor miRNAs, and they play key roles during colorectal carcinogenesis. However, the functions and molecular mechanisms of regulation of miRNAs involved in inflammation-associated CRC are still anecdotal and largely unknown. Consolidating the published results and offering perspective solutions to circumvent CRC, the current review is focused on the role of miRNAs and their regulation in the development of CRC. We have also discussed the model systems adapted by researchers to delineate the role of miRNAs in inflammation-associated CRC.

Role of inflammation in the development of colorectal cancer

2020 ◽  
Vol 20 ◽  
Author(s):  
Sridhar Muthusami ◽  
R. Ileng Kumaran ◽  
Kokelavani Nampalli Babu ◽  
Sneha Krishnamoorthy ◽  
Akash Guruswamy ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Chronic Inflammation ◽  
Interleukin 1 ◽  
Cell Types ◽  
Model Systems ◽  
Cytokine Gene Expression ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Proinflammatory Molecules

: Chronic inflammation can lead to the development of many diseases including cancer. Inflammatory bowel disease (IBD) that includes both ulcerative colitis (UC) and Crohn's disease (CD) are risk factors for the development of colorectal cancer (CRC). Many cytokines produced primarily by the gut immune cells either during or in response to localized inflammation in the colon and rectum are known to stimulate the complex interactions between the different cell types in the gut environment resulting in acute inflammation. Subsequently, chronic inflammation together with genetic and epigenetic changes has been shown to lead to the development and progression of CRC. Various cell types present in the colon such as enterocytes, Paneth cells, goblet cells and macrophages express receptors for inflammatory cytokines and respond to tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), IL-6 and other cytokines. Among the several cytokines produced, TNF-α and IL-1β are the key proinflammatory molecules that play critical roles in the development of CRC. The current review is intended to consolidate the published findings to focus on the role of proinflammatory cytokines, namely TNF-α and IL-1β, on inflammation (and the altered immune response) in the gut, to better understand the development of CRC in IBD, using various experimental model systems, preclinical and clinical studies. Moreover, this review also highlights the current therapeutic strategies available (monotherapy and combination therapy), to alleviate the symptoms or treat inflammationassociated CRC by using monoclonal antibodies or aptamers to block proinflammatory molecules, inhibitors of tyrosine kinases in inflammatory signaling cascade, competitive inhibitors of proinflammatory molecules, and the nucleic acid drugs like small activating RNAs (saRNAs) or microRNA (miRNA) mimics to activate tumor suppressor or repress oncogene/proinflammatory cytokine gene expression.

scholarly journals Association of tumor necrosis factor-alpha -308 G/A and -238 G/A polymorphism with diabetic retinopathy: a systematic review and updated meta-analysis.

2020 ◽  
Author(s):  
Wenna Gao ◽  
Ruilin Zhu ◽  
liu yang
Keyword(s):  
Diabetic Retinopathy ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Meta Analysis ◽  
Entire Group ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Factor Alpha ◽  
Necrosis Factor

Background: Mounting evidence has suggested tumor necrosis factor-alpha (TNF-α) can promote the development of diabetic retinopathy (DR), and TNF-α gene variants may influence DR risk. However, the results are quite different. Objectives: To comprehensively address this issue, we performed the meta-analysis to evaluate the association of TNF-α-308 G/A and -238 G/A polymorphism with DR. Method: Data were retrieved in a systematic manner and analyzed using STATA Statistical Software. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Allelic and genotypic comparisons between cases and controls were evaluated. Results: For the TNF-α-308 G/A polymorphism, overall analysis suggested a marginal association with DR [the OR(95%CI) of (GA versus GG), (GA + AA) versus GG, and (A versus G) are 1.21(1.04, 1.41), 1.20(1.03, 1.39), and 1.14(1.01, 1.30), respectively]. And the subgroup analysis indicated an enhanced association among the European population. For the TNF-α-238 G/A polymorphism, there was mild correlation in the entire group [the OR(95%CI) of (GA versus GG) is 1.55(1.14,2.11) ], which was strengthened among the Asian population. Conclusion: The meta-analysis suggested that -308 A and -238 A allele in TNF-α gene potentially increased DR risk and showed a discrepancy in different ethnicities.

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