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Guo X, Xi L, Li L, Guo J, Jin W, Chang C, Zhang J, Xu C, Chen G. circRNA-14723 promotes hepatocytes proliferation in rat liver regeneration by sponging rno-miR-16-5p. J Cell Physiol 2020; 235:8176-8186. [PMID: 31960969 DOI: 10.1002/jcp.29473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 01/03/2020] [Indexed: 01/04/2023]
Abstract
Circular RNA (circRNA) is a subclass of noncoding RNA (ncRNA) detected within mammalian tissues and cells. However, its regulatory role during the proliferation phase of rat liver regeneration (LR) remains unreported. This study was designed to explore their regulatory mechanisms in cell proliferation of LR. The circRNA expression profile was detected by high-throughput sequencing. It was indicated that 260 circRNAs were differentially expressed during the proliferation phase of rat LR. Among them, circ-14723 displayed a significantly differential expression. We further explored its regulatory mechanism in rat hepatocytes (BRL-3A cells). First, EdU, flow cytometry and western blot (WB) indicated that knocking down circ-14723 inhibited BRL-3A cells proliferation. Second, RNA-Pulldown and dual-luciferase report assay showed that circ-14723 could sponge rno-miR-16-5p. At last, WB showed that the reported target genes of rno-miR-16-5p, CCND1, and CCNE1 were downregulated after knocking down circ-14723. In conclusion, we found that circ-14723 exerted a critical role in G1/S arrest to promote cell proliferation via rno-miR-16-5p/CCND1 and CCNE1 axis in rat LR. This finding further revealed the regulatory mechanisms of circRNA on cell proliferation of LR, and might provide a potential target for clinical problems.
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Affiliation(s)
- Xueqiang Guo
- College of Life Science, Henan Normal University, Xinxiang, China.,State Key Laboratory Cultivation Base for Cell Differentiation Regulation, Henan Normal University, Xinxiang, China
| | - Lingling Xi
- College of Life Science, Henan Normal University, Xinxiang, China.,Henan Engineering Key Laboratory for Bioengineering and Drug Development, Henan Normal University, Xinxiang, China
| | - Lifei Li
- College of Life Science, Henan Normal University, Xinxiang, China.,State Key Laboratory Cultivation Base for Cell Differentiation Regulation, Henan Normal University, Xinxiang, China
| | - Jianlin Guo
- College of Life Science, Henan Normal University, Xinxiang, China.,Henan Engineering Key Laboratory for Bioengineering and Drug Development, Henan Normal University, Xinxiang, China
| | - Wei Jin
- College of Life Science, Henan Normal University, Xinxiang, China.,State Key Laboratory Cultivation Base for Cell Differentiation Regulation, Henan Normal University, Xinxiang, China
| | - Cuifang Chang
- College of Life Science, Henan Normal University, Xinxiang, China.,State Key Laboratory Cultivation Base for Cell Differentiation Regulation, Henan Normal University, Xinxiang, China
| | - Jingbo Zhang
- Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Cunshuan Xu
- College of Life Science, Henan Normal University, Xinxiang, China.,State Key Laboratory Cultivation Base for Cell Differentiation Regulation, Henan Normal University, Xinxiang, China
| | - Guangwen Chen
- College of Life Science, Henan Normal University, Xinxiang, China
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Fujigaki Y. Different modes of renal proximal tubule regeneration in health and disease. World J Nephrol 2012; 1:92-9. [PMID: 24175246 PMCID: PMC3782202 DOI: 10.5527/wjn.v1.i4.92] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 06/10/2012] [Accepted: 07/20/2012] [Indexed: 02/06/2023] Open
Abstract
Tissues are equipped with reasonable strategies for repair and regeneration and the renal proximal tubule (PT) is no exception. New information has become available on the mode of PT regeneration in mammals. Unlike the intestinal epithelium with a high rate of turnover maintained by the stem cell system, the kidney has low turnover under normal physiological conditions. The PT seems to be maintained physiologically by hyperplasia, a regenerating system with self-renewal of mature tubular cells. This mode of regeneration is advantageous for effective replenishment of randomly isolated and eliminated tubular cells by self-renewal of adjacent cells. On the other hand, it has been suggested that dedifferentiation of mature tubular cells plays a role in regeneration after acute kidney injury. Recent studies employing genetic labeling and DNA-labeling techniques have confirmed that the proliferation of preexisting injured mature tubular cells contributes mainly to PT regeneration in ischemic reperfusion injury. This mode of regeneration is beneficial with regard to the rapid reparation of focally injured tubules often induced by ischemic reperfusion injury. What happens, however, when the PT is homogeneously injured with almost no remaining surviving cells Is the PT equipped with another backup regeneration system, e.g., the stem cell system Is it possible that certain types of renal injuries evoke a stem cell response whereas others do not This review focuses on all three possible modes of tissue regeneration (compensatory hyperplasia, dedifferentiation and stem cell system) in mammals and their involvement in PT regeneration in health and disease.
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Affiliation(s)
- Yoshihide Fujigaki
- Yoshihide Fujigaki, First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
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Kim YI, Park SW, Choi IH, Lee JH, Woo HJ, Kim Y. Effect of Orostachys japonicus on Cell Growth and Apoptosis in Human Hepatic Stellate Cell Line LX2. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2012; 39:601-13. [DOI: 10.1142/s0192415x11009068] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Orostachys japonicus (O. japonicus), used to treat diseases such as various cancers, gastric ulcers, fever, hepatitis, arthritis, eczema, for hemostasis, and intoxication in folk medicine, has been an important constituent in many herbal formulae. We demonstrated that the water extract of O. japonicus led to growth inhibition of LX2 cells by inducing apoptosis through the caspase activation, related to the MAPK pathway. O. japonicus inhibited proliferation of LX2 cells in a dose- and time-dependent manner, increased the apoptosis fraction at cell cycle progression with an accompanying DNA fragmentation, and resulted in a significant decrease in Bcl-2 and an increase in Bax mRNA levels. Exposure of LX2 cells to O. japonicus induced caspase-3 activation, however when the LX2 cells were also treated with the pan-caspase inhibitor Z-VAD-FMK and the caspase-3 inhibitor Z-DEVE-FMK, apoptosis was blocked. O. japonicus inhibited anti-apoptotic Mcl-1 protein and MEK/ERK phosphorylation in LX2 cells. The results indicate that O. japonicus inhibits the cell growth of LX2 cells by inducing apoptosis through caspase activity. O. japonicus down-regulated Mcl-1 protein levels and inhibited the phosphorylation of MEK/ERK, suggesting that it mediates cell death in LX2 cells through the down-regulation of Mcl-1 protein via a MEK/ERK-independent pathway.
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Affiliation(s)
- Young Il Kim
- Medical Science Research Institute, Kyung Hee University Medical Center, Seoul 130-702, South Korea
| | - Seung-Won Park
- Department of Agricultural Biology, National Academy of Agricultural Science, Suwon 441-701, South Korea
| | - In-Hwa Choi
- Department of Oriental Ophthalmology, Otorhinolaryngology and Dermatology, East-West Neo Medical Center, Kyung Hee University, Seoul 134-090, South Korea
| | - Jang-Hoon Lee
- Department of Internal Medicine, College of Oriental Medicine Kyung Hee University, Seoul 130-702, South Korea
| | - Hong-Jung Woo
- Department of Internal Medicine, College of Oriental Medicine Kyung Hee University, Seoul 130-702, South Korea
| | - Youngchul Kim
- Department of Internal Medicine, College of Oriental Medicine Kyung Hee University, Seoul 130-702, South Korea
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Shi JH, Huitfeldt HS, Suo ZH, Line PD. Growth of hepatocellular carcinoma in the regenerating liver. Liver Transpl 2011; 17:866-74. [PMID: 21542129 DOI: 10.1002/lt.22325] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Liver resection and liver transplantation are the treatment modalities with the greatest potential for curing hepatocellular carcinoma (HCC). Tumor recurrence after resection for HCC is, however, a major problem, and an increased rate of recurrence after living donor transplantation versus cadaveric whole liver transplantation has been suggested. Factors involved in liver regeneration may stimulate the growth of occult tumors. The aim of this project was to test the hypothesis that a microscopic HCC tumor in the setting of partial hepatectomy would show enhanced growth and signs of increased invasiveness corresponding to the size of the liver resection. Hepatectomy was performed to various degrees in groups of Buffalo rats with the concomitant implantation of a fixed number of hepatoma cells in the remnant liver; a control group underwent only resection. After 21 days, the sizes and numbers of the tumors and the expression of alpha-fetoprotein (AFP), cyclin D1, calpain small subunit 1 (CAPNS1), CD34 (a microvessel density marker), vascular endothelial growth factor (VEGF), and vascular endothelial growth factor receptor 2 (VEGFR2) were evaluated and compared between the groups. The tumor volume and number increased significantly with the size of the partial hepatectomy (P < 0.05). The largest resections were also associated with increased hepatoma cell infiltration in the lungs and significant up-regulation of cyclin D1, AFP, CAPNS1, CD34, VEGF, and VEGFR2. The results suggest that liver regeneration after partial hepatectomy facilitates the growth and malignant transformation of microscopic HCC, and this could be significant for liver resection and partial liver transplantation strategies for HCC.
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Affiliation(s)
- Ji-Hua Shi
- Department of Organ Transplantation, Rikshospitalet, Oslo University Hospital, Oslo, Norway
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Wang YD, Yang F, Chen WD, Huang X, Lai L, Forman BM, Huang W. Farnesoid X receptor protects liver cells from apoptosis induced by serum deprivation in vitro and fasting in vivo. Mol Endocrinol 2008; 22:1622-32. [PMID: 18436567 DOI: 10.1210/me.2007-0527] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The farnesoid X receptor (FXR) is a key metabolic regulator in the liver by maintaining the homeostasis of liver metabolites. Recent findings suggest that FXR may have a much broader function in liver physiology and pathology. In the present work, we identify a novel role of FXR in protecting liver cell from apoptosis induced by nutritional withdrawal including serum deprivation in vitro or starvation in vivo. Two FXR ligands, chenodeoxycholic acid (CDCA) and GW4064, rescued HepG2 cells from serum deprivation-induced apoptosis in a dose-dependent manner. This effect of FXR on apoptotic suppression was compromised when FXR was knocked down by short interfering RNA. Similarly, the effects of both CDCA and GW4064 were abolished after inhibition of the MAPK pathway by a specific inhibitor of MAPK kinase 1/2. Immunoblotting results indicated that FXR activation by CDCA and GW4064 induced ERK1/2 phosphorylation, which was attenuated by serum deprivation. In vivo, FXR(-/-) mice exhibited an exacerbated liver apoptosis and lower levels of phosphorylated-ERK1/2 compared to wild-type mice after starvation. In conclusion, our results suggest a novel role of FXR in modulating liver cell apoptosis.
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Affiliation(s)
- Yan-Dong Wang
- Department of Gene Regulation and Drug Discovery, Beckman Research Institute of City of Hope National Medical Center, Duarte, CA 91010, USA
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Kollmar O, Menger MD, Schilling MK. Macrophage inflammatory protein-2 contributes to liver resection-induced acceleration of hepatic metastatic tumor growth. World J Gastroenterol 2006; 12:858-67. [PMID: 16521212 PMCID: PMC4066149 DOI: 10.3748/wjg.v12.i6.858] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To study the role of macrophage inflammatory protein (MIP)-2 in liver resection-induced acceleration of tumor growth in a mouse model of hepatic metastasis.
METHODS: After a 50% hepatectomy, 1×105 CT26.WT cells were implanted into the left liver lobe of syngeneic balb/c mice (PHx). Additional animals were treated with a monoclonal antibody (MAB452) neutralizing MIP-2 (PHx+mAB). Non-resected and non-mAB-treated mice (Con) served as controls. After 7 d, tumor angiogenesis and microcirculation as well as cell proliferation, tumor growth, and CXCR-2 expression were analyzed using intravital fluorescence microscopy, histology, immunohistochemistry, and flow cytometry.
RESULTS: Partial hepatectomy increased (P < 0.05) the expression of the MIP-2 receptor CXCR-2 on tumor cells when compared with non-resected controls, and markedly accelerated (P < 0.05) angiogenesis and metastatic tumor growth. Neutralization of MIP-2 by MAB452 treatment significantly (P < 0.05) depressed CXCR-2 expression. Further, the blockade of MIP-2 reduced the angiogenic response (P < 0.05) and inhibited tumor growth (P < 0.05). Of interest, liver resection-induced hepatocyte proliferation was not effected by anti-MIP-2 treatment.
CONCLUSION: MIP-2 significantly contributes to liver resection-induced acceleration of colorectal CT26.WT hepatic metastasis growth.
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Affiliation(s)
- Otto Kollmar
- Department of General, Visceral, Vascular and Pediatric Surgery, University of the Saarland, D-66421 Homburg/Saar, Germany.
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Laurent S, Stärkel P, Leclercq IA, Lambotte L, Maiter D, Horsmans Y. Molecular events associated with accelerated proliferative response in rat livers when partial hepatectomy is preceded by a sham operation. Eur J Clin Invest 2005; 35:140-7. [PMID: 15667586 DOI: 10.1111/j.1365-2362.2005.01449.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND When a sham operation is performed 6 h before partial hepatectomy (PH), the regenerative response is accelerated suggesting that sham operation itself contributes to cellular events leading to proliferation. MATERIALS AND METHODS In order to examine the mechanisms implicated in this acceleration, we compared the activation of several factors associated with the progression through the cell cycle at various times after PH and after PH preceded by sham operation (S6 h + PH). The effect of a single sham (S) and two combined sham operations (S6 h + S) was also examined. Nonoperated rats were used as controls (C). RESULTS The early factors NF-kappaB and Stat3 were activated after S6 h + PH and S6 h + S. C-jun expression was increased 0.5 h and 2 h after PH and 6 h after sham. There was no further increase in S6 h + PH and S6 h + S. In contrast, c-myc expression returned to baseline levels after S6 h and a new increase was observed 2 h after S6 h + PH but not after S6 h + S. P53 mRNA was significantly expressed 6 h after S6 h + PH, but at a level similar than that observed 6 and 12 h after PH alone. An earlier increase in c-Ha-ras mRNA and cyclin E protein was found in S6 h + PH, in comparison with PH alone. CONCLUSIONS The first divergent response between the two combined models involved c-myc expression. However, major differences related to the accelerated liver regenerative response observed after S6 h + PH were found at late time points associating an earlier expression of c-Ha-ras and nuclear cyclin E.
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Affiliation(s)
- S Laurent
- Department of Gastroenterology, Université Catholique de Louvain, 1200 Brussels, Belgium
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Affiliation(s)
- Adrian Reuben
- Division of Gastroenterology and Hepatology, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA
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Akcali KC, Dalgic A, Ucar A, Haj KB, Guvenc D. Expression of bcl-2 gene family during resection induced liver regeneration: comparison between hepatectomized and sham groups. World J Gastroenterol 2004; 10:279-83. [PMID: 14716839 PMCID: PMC4717020 DOI: 10.3748/wjg.v10.i2.279] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2003] [Revised: 10/05/2003] [Accepted: 10/12/2003] [Indexed: 12/15/2022] Open
Abstract
AIM During liver regeneration cellular proliferation and apoptosis result in tissue remodeling to restore normal hepatic mass and structure. Main regulators of the apoptotic machinery are the Bcl-2 family proteins but their roles are not well defined throughout the liver regeneration. We aimed to analyze the expression levels of bcl-2 gene family members during resection induced liver regeneration. METHODS We performed semi-quantitative RT-PCR to examine the expression level of bak, bax, bcl-2 and bcl-xL in 70% hepatectomized rat livers during the whole regeneration process and compared to that of the sham and normal groups. RESULTS The expression of bak and bax was decreased whereas that of bcl-2 and bcl-xL was increased in hepatectomized animals compared to normal liver at most time points. We also reported for the first time that sham group of animals had statistically significant higher expression of bak and bax than hepatectomized animals. In addition, the area under the curve (AUC) values of these genes was larger in sham groups than the hepatectomized groups. CONCLUSION The expression changes of bak, bax, bcl-2 and bcl-xL genes are altered not only due to regeneration, but also due to effects of surgical operations.
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Affiliation(s)
- Kamil Can Akcali
- Department of Molecular Biology and Genetics, Bilkent University, Bilkent, Ankara 06800, Turkey.
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Taber DJ, Dupuis RE, Fann AL, Andreoni KA, Gerber DA, Fair JH, Johnson MW, Shrestha R. Tacrolimus dosing requirements and concentrations in adult living donor liver transplant recipients. Liver Transpl 2002; 8:219-23. [PMID: 11910566 DOI: 10.1053/jlts.2002.30885] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Living donor liver transplantation in adult recipients is becoming increasingly common. The liver metabolizes most drugs, including immunosuppressive agents. Right-lobe grafts used in adult living donor liver transplantation consist of only 50% to 60% of the total liver. The purpose of this study is to determine whether there is a difference between tacrolimus doses and concentrations in patients who received a partial liver transplant from a living donor (LRD) versus those who received a whole-liver transplant from a cadaveric donor (CAD). Thirteen LRD recipients and 13 CAD recipients who underwent transplantation between April 1998 and July 2000 were included in this analysis. A CAD control group matched for age, sex, and race was used for comparison. Tacrolimus doses and concentrations were analyzed weekly for the first 4 weeks, then monthly for 6 months posttransplantation. There was no difference in acute rejection rates, renal and liver function test results, or number of potentially interacting medications administered between groups. LRD recipients required significantly lower doses of tacrolimus compared with CAD recipients at 2 weeks (0.058 v 0.110 mg/kg/d; P <.01), 3 weeks (0.068 v 0.123 mg/kg/d; P <.02), 4 weeks (0.086 v 0.141 mg/kg/d; P <.02), 2 months (0.097 v 0.141 mg/kg/d; P <.03), and 3 months (0.099 v 0.138 mg/kg/d; P <.03). Tacrolimus 12-hour trough concentrations were similar between groups at all times except for 2 weeks posttransplantation, when LRD recipients' concentrations were significantly greater than those of CAD recipients (12.4 v 9.5 ng/mL; P <.03). In addition, in the first month posttransplantation, LRD recipients were more likely to have greater concentrations of tacrolimus (>15 ng/mL; 22.1% v 9.2%; P <.01). In conclusion, LRD recipients have significantly decreased tacrolimus dosing requirements compared with CAD recipients during the first 3 months posttransplantation despite having similar tacrolimus concentrations.
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Affiliation(s)
- David J Taber
- Department of Pharmacy, University of North Carolina School of Pharmacy and Medicine, Chapel Hill, NC 27599, USA
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Fan YD, Praet M, Van Huysse J, Lelie B, De Hemptinne B. Effects of portal vein arterialization on liver regeneration after partial hepatectomy in the rat. Liver Transpl 2002; 8:146-52. [PMID: 11862591 DOI: 10.1053/jlts.2002.30887] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although portal venous supply is considered essential to preserve hepatic integrity, in this study, effects of portal arterialization on liver regeneration were evaluated in a rat model of partial hepatectomy (PH). Ninety-six Lewis rats were randomly assigned to four groups of 24 rats each: PH only (group 1), PH with either venous or arterialized portal supply (groups 2 and 3, respectively), and PH without portal supply (group 4). Liver regeneration rate (LRR), 5-bromo-2-deoxyuridine (BrdU) labeling index, and liver biological characteristics were assessed on days 1, 2, 3, and 7. Compared with group 1, all tested rats had a marked body weight loss after surgery, and only rats in group 4 showed no signs of recovery on day 7. With maintained portal inflow (groups 1, 2, and 3), LRRs increased steadily to day-7 values of 89.2% +/- 11.8%, 81.4% +/- 8%, and 77.4% +/- 9.4%, respectively (P = not significant), and 24-hour peak values of BrdU labeling index were 159 +/- 26, 157 +/- 42, and 149 +/- 48, respectively (P = not significant). Conversely, rats deprived of portal supply (group 4) showed profound inhibition of these two parameters (14 +/- 13; P <.01;32.1% +/- 7.7%; P <.001, respectively). These results indicate that proper portal blood supply is essential to initiate and maintain liver regeneration after PH. With an equivalent portal inflow rate of either venous or arterial source, the hepatic regeneration response can be sustained.
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Affiliation(s)
- Ye-Dong Fan
- Department of Surgery, University Hospital of Ghent, Belgium.
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Chen Z, Felsheim R, Wong P, Augustin LB, Metz R, Kren BT, Steer CJ. Mitochondria isolated from liver contain the essential factors required for RNA/DNA oligonucleotide-targeted gene repair. Biochem Biophys Res Commun 2001; 285:188-94. [PMID: 11444824 DOI: 10.1006/bbrc.2001.5156] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chimeric RNA/DNA oligonucleotides (ONs) have been used successfully for site-specific modifications of episomal and chromosomal DNA in eukaryotic cells. We explored the possibility of applying this technique to mitochondrial DNA, as single-nucleotide defects in this genome are associated with a series of human diseases. Therefore, we determined whether mitochondria possess the enzymatic machinery for chimeric ON-mediated DNA alterations. We utilized an in vitro DNA repair assay and an Escherichia coli readout system with mutagenized plasmids carrying point mutations in antibiotic resistance genes. RNA/DNA ONs were designed to correct the defects and restore kanamycin and tetracyclin resistance. Using this system, we demonstrated that extracts from highly purified rat liver mitochondria possess the essential enzymatic activity to mediate precise single-nucleotide changes. Interestingly, the frequency of gene conversion was similar in both mitochondrial and nuclear extracts, as well as from quiescent and regenerating liver. The results indicate that mitochondria contain the machinery required for repair of genomic single-point mutations, and suggest that RNA/DNA ONs may provide a novel approach to the treatment of certain mitochondrial-based diseases.
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Affiliation(s)
- Z Chen
- Department of Medicine, University of Minnesota Medical School, 420 Delaware St. S.E., Minneapolis, MN 55455, USA
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Kren BT, Rodrigues CM, Setchell KD, Steer CJ. Modulation of steady-state messenger RNA levels in the regenerating rat liver with bile acid feeding. Liver Transpl 2001; 7:321-34. [PMID: 11303292 DOI: 10.1053/jlts.2001.23062] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Liver regeneration after two thirds partial hepatectomy (PH) is an orchestrated hyperplastic growth process requiring coordinated expression of many genes. The synchronous progression of 95% of the remnant hepatocytes through the cell cycle provides an in vivo model for examining the influence of bile acids on the molecular regulation of hepatocyte replication and growth. In this study, we examined the effects of endogenous deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) on messenger RNA (mRNA) expression and growth rate during liver regeneration. Rats were fed diets containing no addition, 0.4% DCA, UDCA, or both for 14 days; they then underwent 70% PH and were maintained on the diets for an additional 14 days. mRNA transcript levels for a variety of cell cycle-regulated genes were examined post-PH by Northern blot analysis. Bile acid concentrations were determined in liver, isolated nuclei, and plasma by gas chromatography and mass spectrometry. The results indicated that the addition of DCA and UDCA to the diet markedly shifted the bile-acid compositions of liver and plasma. In addition, DCA dramatically altered the abundance of many transcripts post-PH, whereas coadministration of UDCA suppressed the effect. DCA feeding significantly inhibited liver growth through day 3; however, by day 8, it induced an approximately 20% increase in mass compared with controls, UDCA-fed, or combination-fed animals. UDCA was concentrated greater than 20-fold in nuclei compared with whole liver in controls and DCA-fed animals and greater than 2-fold with UDCA feeding. These data suggest that bile acids may have a key role in liver regeneration, which is significantly altered by modulation of the bile-acid pool.
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Affiliation(s)
- B T Kren
- Department of Medicine, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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Frago LM, Pañeda C, Fabregat I, Varela-Nieto I. Short-chain ceramide regulates hepatic methionine adenosyltransferase expression. J Hepatol 2001; 34:192-201. [PMID: 11281546 DOI: 10.1016/s0168-8278(00)00022-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND The metabolism of methionine plays an important role in regulating hepatic cellular function. Methionine adenosyltransferase (MAT) is the enzyme that catalyses the biosynthesis of S-adenosylmethionine (AdoMet) from ATP and methionine. Liver-specific MAT I/III levels are down-regulated in the regenerating rat liver after partial hepatectomy. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) are two cytokines fundamental for liver regeneration. TNF-alpha stimulates sphingomyelin metabolism and ceramide generation in a variety of cell systems. AIMS The role of exogenous cell-permeable ceramide in modifying MAT I/III mRNA levels and its association with TNF-alpha and IL-6 actions were investigated in rat hepatocytes and H35 hepatoma cells. RESULTS C2-ceramide (N-acetylsphingosine) at 1-10 microM decreased MAT I/III expression. The effect was maximum after 2 h of treatment and it was maintained up to 24 h. MAT I/III protein levels also decreased. IL-6 (1-10 ng/ml) potentiated C2-ceramide effects in cultured hepatocytes while decreasing by itself MAT I/III levels with a similar time-response curve in both cell types. C2-ceramide actions were not associated with an increase in cell death. TNF-alpha was also a potent antagonist for MAT I/III expression, at 1-20 ng/ml decreased MAT I/III levels and induced endogenous ceramide generation. The decrease of MAT I/III mRNA levels (in all the cases) was not due to a decrease in mRNA half-life which suggests a regulation at the transcriptional level. Finally, the decrease in MAT I/III mRNA levels correlated to a decrease in MAT activity. CONCLUSION This work demonstrates that short-chain ceramide can be used as a novel exogenous agonist that can modulate hepatic methionine metabolism in association with cytokines.
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Affiliation(s)
- L M Frago
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Spain
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Marcos A, Fisher RA, Ham JM, Shiffman ML, Sanyal AJ, Luketic VA, Sterling RK, Fulcher AS, Posner MP. Liver regeneration and function in donor and recipient after right lobe adult to adult living donor liver transplantation. Transplantation 2000; 69:1375-9. [PMID: 10798757 DOI: 10.1097/00007890-200004150-00028] [Citation(s) in RCA: 236] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Regeneration of the liver to a predetermined size after resection or transplantation is a well described phenomenon, but the time course over which these events occur has not been well defined. It is not clear how initial liver mass, reperfusion, immunosuppression, or steatosis influence this process. METHODS Liver regeneration was assessed prospectively by volumetric magnetic resonance imaging (MRI) in living right lobe liver donors and the recipients of these grafts. Imaging was performed at regular intervals through 60 days after resection/transplantation, and liver mass was determined. Liver function tests and synthetic function were monitored throughout the study period in donors and recipients of these grafts as well as recipients of cadaveric grafts. RESULTS MRI consistently overestimated liver mass by a mean of 45 g (+/-65) (range 10-123). Donor liver mass increased by 101%, 110%, 115%, and 144% at 7, 14, 30, and 60 days after resection, respectively. Recipient liver mass increased by 87,101, 119, and 99% at 7, 14, 30, and 60 days after transplantation, respectively. Steatosis did not influence the degree of regeneration or graft function, nor was there a functional difference between grafts of >1% graft to recipient body weight ratio or <1%. CONCLUSIONS MRI accurately determines right lobe mass. Most liver regeneration occurs in the 1st week after resection or transplantation, and the time course does not differ significantly in donors or recipients. The mass of the graft or remnant segment affects the duration of the regeneration process, with a smaller initial liver mass prolonging the course. Steatosis of <30% had no bearing on liver function or regeneration and, therefore, should not be an absolute criterion for exclusion of donors. A calculated graft to recipient body weight ratio of 0.8% is adequate for right lobe living donor liver transplantation.
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Affiliation(s)
- A Marcos
- Department of Surgery, Medical College of Virginia, Virginia Commonwealth University, Richmond 23219, USA
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Chen W, Woodruff TK, Mayo KE. Activin A-induced HepG2 liver cell apoptosis: involvement of activin receptors and smad proteins. Endocrinology 2000; 141:1263-72. [PMID: 10698204 DOI: 10.1210/endo.141.3.7361] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A balance between cell proliferation and apoptosis is important for regulating normal liver function. Proteins of the transforming growth factor-beta superfamily are known to be important mediators of apoptosis in the liver. In this study we demonstrate that activin A potently induces apoptotic cell death in a hepatoma cell line, HepG2 cells. To determine the roles of activin receptors and downstream signaling proteins in activin A-induced apoptosis in these cells, the activin signaling pathway was analyzed using the transcription of an activin-responsive reporter gene, p3TP-Lux, as an assay. Although individual activin receptors had little effect on transcriptional activity, coexpression of an activin type I receptor and a type II receptor significantly increased both basal and activin-induced transcriptional activation, with the combination ofreceptors IB and IIB being the most potent. Similarly, expression of individual Smad proteins had only a modest effect on reporter gene activity, but the combination of Smad2 and Smad4 strongly stimulated transcription. Activin signaling induced a rapid relocation of Smad2 to the nucleus, as determined using a green fluorescence protein-Smad2 fusion protein. In contrast, green fluorescence protein-Smad4 remained localized to the cytoplasm unless it was coexpressed with Smad2. In agreement with the transcriptional response assays, overexpression or suppression of activin signaling components in HepG2 cells altered apoptosis. Overexpression of receptors IB and IIB or Smad proteins 2 and 4 stimulated apoptosis, whereas dominant negative mutant forms of the activin type IIB receptor or Smad2 blocked activin-stimulated apoptosis. These studies suggest that signaling from the cell surface to the nucleus through Smad proteins is a required component of the activin A-induced cell death process in liver cells.
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Affiliation(s)
- W Chen
- Department of Biochemistry, Center for Reproductive Science, Northwestern University, Evanston, Illinois 60208, USA
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Abstract
The continuing shortage of organs for adult transplant recipients has generated enthusiasm for adult-to-adult living donor liver transplantation (LDLT). The major concern has been the ability to resect a graft of adequate size without subjecting the donor to undue risk. The right hepatic lobe is generally large enough for adult recipients, but because of the real and perceived risks of right lobe (RL) resection, surgeons have been hesitant to offer this option to their patients. The first series of RL resections that included a significant number of patients was reported in 1999, and the results were encouraging. Only minor complications occurred in donors, and the recipients fared quite well. Enthusiasm for these donor resections is growing, and more centers are beginning to perform them. There is a good deal of global experience with pediatric LDLT but little with adults, and there are unique considerations in this population. This review examines donor selection criteria for adult recipients, highlights technical points critical for good outcome, and examines the early results and complications in both donors and recipients. If the preliminary results continue to be reproduced, RL LDLT could have significant impact on the worsening organ shortage.
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Affiliation(s)
- A Marcos
- Department of Surgery, Division of Transplantation, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298-0057, USA
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Patel T, Steer CJ, Gores GJ. Apoptosis and the liver: A mechanism of disease, growth regulation, and carcinogenesis. Hepatology 1999; 30:811-5. [PMID: 10462391 DOI: 10.1002/hep.510300334] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- T Patel
- Division of Gastroenterology, Scott and White Clinic, Texas A&M University System Health Science Center College of Medicine, Temple, TX 76508, USA.
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