Effect of chylomicron remnants on apolipoprotein E synthesis in HepG2 cells

Teramoto, Tamio; Matsushima, Teruhiko; Kinoshita, Makoto; Watanabe, Tsuyoshi; Hashimoto, Yoshiaki; Tsukamoto, Kazuhisa; Katsuragawa, Keita; Okazaki, S.; Yamanaka, Masami

doi:10.1016/0026-0495(94)90156-2

Cited by 3 publications

(1 citation statement)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After chasing, the medium was removed and the cells were extracted by addition of 0.5 ml of the lysis buffer containing 0.15 M NaCl, 5 m M EDTA, 1% Triton X-100 (Sigma), and 0.05 M Tris-HCl (pH 7.4). Newly synthesized apoB in the medium and cell lysate was immunoprecipitated using a specific antiserum, as previously described (31). This anti-human apoB antiserum was raised in a rabbit in the First Department of Internal Medicine, Teikyo University School of Medicine, and was determined to be monospecific to human apoB by Western blotting analysis (data not shown).…”

Section: Pulse-chase Studymentioning

confidence: 99%

Interleukin-1β and interleukin-6 increase levels of apolipoprotein B mRNA and decrease accumulation of its protein in culture medium of HepG2 cells

Yokoyama

Ishibashi

Liang

et al. 1998

Journal of Lipid Research

Self Cite

View full text Add to dashboard Cite

The purpose of the present study was to examine the regulation of levels of apolipoprotein B (apoB) mRNA and its protein by cytokines in HepG2 cells. A dose-dependent increase in apoB mRNA levels was observed in the presence of either interleukin-1 ␤ (IL-1 ␤ ) or IL-6 alone. This increase occurred as early as 1 h after IL-1 ␤ or IL-6 stimulation. Exogenous addition of IL-1 ␤ (5 ng/ml) and IL-6 (50 ng/ml) induced 2.8-and 2.1-fold increases as a result of 18 h of culture, respectively. Co-stimulation with IL-1 ␤ and IL-6 significantly enhanced the increase in apoB mRNA levels stimulated with either cytokine alone. Treatment with cycloheximide prevented the induction of apoB mRNA by IL-1 ␤ , but not by IL-6. These findings suggest that enhancement of apoB mRNA levels by these cytokines is mediated through different pathways. Conversely, IL-1 ␤ and IL-6 lowered the accumulation of apoB protein levels in the culture medium. The pulse-chase study showed that addition of N-acetyl leucyl leucyl norleucinal to the medium induced a decrease in newly synthesized apoB in the cell lysate in response to IL-1 ␤ ( P Ͻ 0.05) or IL-6 (not to a significant extent) compared with control. These findings demonstrated that the lower level of apoB in the medium was caused by the enhanced intracellular degradation. In addition, IL-1 ␤ increased LDL receptor mRNA levels as well as protein activity, although IL-6 did not, suggesting that the more marked decrease in apoB accumulation in the medium induced by IL-1 ␤ compared with that induced by IL-6 may reflect an increased uptake of apoB from the medium by IL-1 ␤ . The present study demonstrates that a cytokine network may be involved in the metabolism of apoB under certain conditions such as inflammation.-Yokoyama, K., T. Ishibashi, L. Yiqiang, A. Nagayoshi, T. Teramoto, and Y. Maruyama. Interleukin-1 ␤ and interleukin-6 increase levels of apolipoprotein B mRNA and decrease accumulation of its protein in culture medium of HepG2 cells.

show abstract

Section: Pulse-chase Studymentioning

confidence: 99%

Interleukin-1β and interleukin-6 increase levels of apolipoprotein B mRNA and decrease accumulation of its protein in culture medium of HepG2 cells

Yokoyama

Ishibashi

Liang

et al. 1998

Journal of Lipid Research

Self Cite

View full text Add to dashboard Cite

show abstract

Post-transcriptional regulation of apoC-I synthesis and secretion in human HepG2 cells

et al. 2005

View full text Add to dashboard Cite

Skipping of Exon 14 and Possible Instability of Both the mRNA and the Resultant Truncated Protein Underlie a Common Cholesteryl Ester Transfer Protein Deficiency in Japan

Gotoda

Kinoshita

Ishibashi

et al. 1997

ATVB

View full text Add to dashboard Cite

Among the Japanese population, a G-to-A mutation at the beginning of intron 14 of the human cholesteryl ester transfer protein (CETP) gene is a frequent cause of CETP deficiency characterized by markedly increased HDL cholesterol. The resulting abnormalities responsible for null CETP deficiency were studied in detail. The CETP mRNA transcripts amplified by polymerase chain reaction from the monocyte-derived macrophages of two homozygous patients were both found to be normal except for the whole deletion of exon 14. The deletion causes a shift of reading frame and introduces a premature termination codon downstream. Examination of the macrophage RNA from heterozygotes suggested the increased instability of the abnormal mRNA in the cytoplasm, because the amount of the aberrant transcript was nearly one third that of a normal transcript in the cytoplasm, while they were equal in the nucleus. Although this indicated the synthesis of a mutant CETP that lacks about 15% at its carboxy terminus, immunoblot analysis demonstrated that the abnormal CETP was virtually absent in both the media and cell lysates of transfected COS-1 cells, which massively expressed the mutant CETP mRNA. These results elucidate the primary abnormality due to the common CETP splicing mutation to be the exon skipping of mRNA, which decreases the level of mRNA and produces a truncated protein that should be rapidly degraded intracellularly.

show abstract

Effect of chylomicron remnants on apolipoprotein E synthesis in HepG2 cells

Cited by 3 publications

References 25 publications

Interleukin-1β and interleukin-6 increase levels of apolipoprotein B mRNA and decrease accumulation of its protein in culture medium of HepG2 cells

Interleukin-1β and interleukin-6 increase levels of apolipoprotein B mRNA and decrease accumulation of its protein in culture medium of HepG2 cells

Post-transcriptional regulation of apoC-I synthesis and secretion in human HepG2 cells

Skipping of Exon 14 and Possible Instability of Both the mRNA and the Resultant Truncated Protein Underlie a Common Cholesteryl Ester Transfer Protein Deficiency in Japan

Contact Info

Product

Resources

About