MCP-1/MCPIP-1 Signaling Modulates the Effects of IL-1ß in Renal Cell Carcinoma through ER Stress-Mediated Apoptosis.

In renal cell carcinoma (RCC), interleukin (IL)-1ß may be a pro-metastatic cytokine. However, we have not yet noted the clinical association between tumoral expression or serum level of IL-1ß and RCC in our patient cohort. Herein, we investigate molecular mechanisms elicited by IL-1ß in RCC. We found that IL-1ß stimulates substantial monocyte chemoattractant protein (MCP)-1 production in RCC cells by activating NF-kB and AP-1. In our xenograft RCC model, intra-tumoral MCP-1 injection down-regulated Ki67 expression and reduced tumor size. Microarray analysis revealed that MCP-1 treatment altered protein-folding processes in RCC cells. MCP-1-treated RCC cells and xenograft tumors expressed MCP-1-induced protein (MCPIP) and molecules involved in endoplasmic reticulum (ER) stress-mediated apoptosis, namely C/EBP Homologous Protein (CHOP), protein kinase-like ER kinase (PERK), and calnexin (CNX). ER stress-mediated apoptosis in MCP-1-treated RCC cells was confirmed using Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL) assay. Moreover, ectopic MCPIP expression increased PERK expression in Human embryonic kidney (HEK)293 cells. Our meta-analysis revealed that low MCP-1 levels reduce 1-year post-nephrectomy survival in patients with RCC. Immunohistochemistry indicated that in some RCC biopsy samples, the correlation between MCP-1 or MCPIP expression and tumor stages was inverse. Thus, MCP-1 and MCPIP potentially reduce the IL-1ß-mediated oncogenic effect in RCC; our findings suggest that ER stress is a potential RCC treatment target.

Clinical association between the metabolite of healthy gut microbiota, 3-indolepropionic acid and chronic kidney disease.

BACKGROUND & AIMS: Emerging evidence indicates that gut microbiota serves an important role in the development and progression of chronic kidney disease (CKD). Changes to the gut microbial flora can cause the generation of uremic toxins, which contribute to chronic kidney injury. The aim of the current study was to explore the clinical association between metabolites and CKD. METHODS: Between August 2013 and January 2015, a two-phase case-control study was conducted to analyze the clinical association between metabolites and CKD in a community health program. The first phase of the study was a prospective case-control survey designed for comparing the differences in the metabolome profile of patients with (n = 10) and without (n = 10) estimated glomerular filtration rate (eGFR) rapid decline (a yearly decline >20%). The second phase of the study was a cross-sectional case-control study, which checked and compared the metabolites, indoxyl sulfate and p-cresol sulfate levels between healthy subjects (n = 144) and CKD patients (n = 140). RESULTS: In the first phase of the study, it was revealed that IPA levels of patients with rapid renal function decline were significantly reduced compared with the control patients (n = 10 for each group). The second phase furthered checked and compared the IPA, indoxyl sulfate and p-cresol sulfate levels between healthy subjects (n = 144) and CKD patients (n = 140). The results showed that the average level of indoxyl sulfate (2738.2 vs. 541.0 ng/ml, P < 0.01) and p-cresol sulfate (1442.8 vs. 1394.6 ng/ml, P < 0.01) were significantly higher in the CKD patients, while the average level of IPA was significantly higher (49.8 vs. 34.7 ng/ml, P < 0.01) in the control patients. CONCLUSIONS: Our results suggest that IPA might be an important biomarker and renal protector against the development of CKD.

Serum levels of uncoupling proteins in patients with differential insulin resistance: A community-based cohort study.

The uncoupling protein (UCP) belongs to a family of energy-dissipating proteins in mitochondria. Increasing evidences have indicated that UCPs have immense impact on glucose homeostasis and are key proteins in metabolic syndrome. For applying the findings to clinical practice, we designed a study to explore the association between serum UCPs 1-3 and insulin resistance. This investigation prospectively recorded demographical parameter and collected blood samples of 1071 participants from 4 districts in Northeastern Taiwan during the period from August 2013 to July 2014. Propensity score matching by age and sex in patients with top and bottom third homeostasis model assessment of insulin resistance (HOMA-IR) levels was performed, and 326 subjects were enrolled for further studies. The mean age of the patients was 59.4 years and the majority of them (65.5%) were females. The prevalence of metabolic syndrome was 35.5%. Our results demonstrated that serum UCPs 1-3 were significantly associated with differences in HOMA-IR levels. Multiple logistic regression analysis indicated that low UCP 1 and features of metabolic syndrome, namely hypertension, diabetes, body mass index, and high-density lipoprotein, were independent determinants for high HOMA-IR levels. We thus determined that low serum UCP 1 is a predictor for high resistance to insulin.

Propofol-enhanced autophagy increases motility and angiogenic capacity of cultured human umbilical vascular endothelial cells.

AIMS: Propofol (PPF), an intravenous anesthetic agent, is previously reported to attenuate oxidative stress- and inflammation-induced endothelial cell dysfunction. This study investigated its effect on endothelial cell biology. MAIN METHODS: Cultured human umbilical vein endothelial cells (HUVECs) were treated with PPF and subject to measurements for nitric oxide (NO) production, autophagy flux, signal transduction, migration, and in vitro angiogenesis. KEY FINDINGS: Non-cytotoxic PPF treatment was found to significantly upregulate inducible nitric oxide synthase (NOS2) but downregulate constitutive NOS3 expression. It also potentiated LPS-induced ICAM-1 overexpression and NO overproduction. Mechanistically, the PPF-activated signal transduction in PI3K/Akt, ERK1/2, p38 MAPK, and JNK pathways were involved in the PPF-driven NO overproduction. PPF exhibited a stimulatory effect on autophagy flux by increasing expression of autophagy markers including mTOR, Beclin-1, Atg5, and LC3I/II, as well as a late endosomal indicator, Rab7. However, PPF appeared to antagonize the Rab7 upregulation by LPS. Functionally, PPF enhanced in vitro migratory and angiogenic capacities of HUVECs, but this enhancement was drastically abrogated by the presence of autophagy inhibitors, indicating a pro-angiogenic contribution of PPF-enhanced autophagy in cultured HUVECs. SIGNIFICANCE: Our findings support the notion that PPF enhances motility and angiogenic capacity of cultured HUVECs through an autophagy-involved regulatory mechanism.

Toll-like receptor-4 is a target for suppression of proliferation and chemoresistance in HepG2 hepatoblastoma cells.

Toll-like receptor-4 (TLR4) is known to influence growth and migration of hepatocellular tumors; however, its role in hepatoblastoma remains poorly understood. This study investigated the regulatory role of TLR4 in proliferation and chemoresistance of HepG2 hepatoblastoma cells. Treatment with lipopolysaccharide (LPS), a TLR4 agonist, was found to significantly upregulate TLR4 expression in HepG2 cells, but not in malignant Huh-7 and Sk-Hep1 hepatocellular carcinoma cells. Additionally, IL-6 enhanced LPS-induced TLR4 upregulation. LPS-stimulated TLR4 activation increased proliferation, nitric oxide synthase (NOS) expression, and NO production in HepG2 cells. Chemotherapeutic agents, cisplatin and doxorubicin, effectively inhibited TLR4 expression in HepG2 cells. Characterization of LPS-induced signaling activation and blockade with kinase inhibitors revealed the involvement of Akt and MAPK pathways in LPS-enhanced NO release from, and proliferation of HepG2 cells. Mechanistically, gene modifications as a result of TLR4 transfection and siRNA-mediated knockdown further demonstrated a crucial role for TLR4 in the regulation of NOS expression, cell proliferation, and chemoresistance in HepG2 cells. These findings suggest that targeting TLR4 expression and its cognate signaling may modulate proliferation and chemosensitivity in hepatoblastoma cells and serve as a potential therapeutic target.

A novel exo-cellulase from white spotted longhorn beetle (Anoplophora malasiaca).

Wood feeding insects depends heavily on the secretion of a combination of cellulases, mainly endoglucanases and other glucanases such as exoglucanases and xylanases, for efficient digestion of the cellulosic materials. To date, although a high number of endoglucanases have been found in xytophagous insects, little is known about exoglucanases encoded in the genome of these insects. Here we report the identification and isolation of an exoglucanase, designated as AmCel-5B, from the white spotted longhorn beetle, Anoplophora malasiaca. The optimal condition of enzymatic activity was found to be 50 °C and pH 4.0. Interestingly, this enzyme is not only exhibited exo-ß-glucanase activity, but also with obvious endo-ß-glucanase activity. Furthermore, this enzyme is unique in that, although it recognizes Avicel, evidenced as an exo-ß-glucanase, it cannot recognize oligosaccharides smaller than cellohexaose. This may explain why longhorn beetle can well digest hard "living" wood, which contains primarily rigid long fibers. Although it is known that metal ions can enhance the activity of some cellulases, we further demonstrated that reducing agent could work synergistically with metal ions for significant activity enhancement of AmCel-5B. The discovery and investigation of an insect exoglucanase should lead to a greater understanding of the mechanism for efficient digestion of cellulosic materials by wood feeding insects, as well as facilitate their potential applications in the production of bioenergy and biomaterials from lignocellulosic biomass in the future.