Expression Patterns of the Cell Junction-associated Genes During Rat Liver Regeneration

Increased Expression of Adherens Junction Components in Mouse Liver following Bile Duct Ligation

Adherens junctions, consisting of cadherins and catenins, are a group of cell-to-cell junctions that mediate mechanistic linkage between neighboring cells. By doing so, adherens junctions ensure direct intercellular contact and play an indispensable role in maintaining tissue architecture. Considering these critical functions, it is not surprising that adherens junctions are frequently involved in disease. In the present study, the effects of bile duct ligation—a surgical procedure to experimentally induce cholestatic and fibrotic liver pathology—on hepatic adherens junctions were investigated in mice. In essence, it was found that liver mRNA and protein levels of E-cadherin, β-catenin and γ-catenin drastically increase following bile duct ligation. These results could suggest a cytoprotective role for hepatic adherens junctions following bile duct ligation.

Study on the anti-endotoxin effect of sinomenine using an Agilent genome array

BACKGROUND

Endotoxin is a significant contributing factor underlying the occurrence of fever, diarrhea, inflammation, edema, coagulation, shock and other syndromes associated with gram-negative bacterial infections. To date, there is no effective treatment for endotoxemia.

AIM

The aim of this study was to characterize differentially expressed genes in sinomenine-treated and lipopolysaccharide (LPS)-induced endothelial cells by microarray analysis and to determine the potential pharmacological activity of sinomenine.

DESIGN

The cultured cells of five treatment groups (n = 3) were collected. Participants: total RNA was extracted and subjected to Agilent Porcine 4 × 44 K whole genome microarray.

METHODS

Kyoto encyclopedia of genes and genomes and gene ontology software were applied to screen and analyze differentially regulated genes.

RESULTS

The results showed that 723 differentially regulated genes were identified including 410 up-regulated genes and 313 down-regulated genes in therapy group vs. LPS group. Ten genes may be key controlled genes in the pathogenesis of LPS, including five up-regulated genes (ARG1, TLR2, IL1A, VCAM1, DKK3) and five down-regulated genes (HABP2, ID1, CHDH, GPX3, PTGFR), which primarily contribute to biological processes such as inflammatory response, vascular lesion, metabolic process and cell cycle. IL1A and FMO3 were considered as potent target genes.

CONCLUSION

Global gene expression profile analysis showed that sinomenine might effectively be useful to regulate inflammatory responses as part of future anti-endotoxin therapies.

Correlation analysis between gene expression profile of high-fat emulsion-induced non-alcoholic fatty liver and liver regeneration in rat

To explore the relevance of non-alcoholic fatty liver disease (NAFLD) to liver regeneration (LR), rat models of non-alcoholic steatohepatitis (NASH) and LR were established, respectively, then Rat Genome 230 2.0 Array was used to detect the gene expression abundance of them, and the reliabilities of the array data were confirmed by real-time RT-PCR. As a result, the expression of 93 genes was significantly changed during NAFLD occurrence and 948 genes in LR. Hierarchical clustering indicated that the expression profiles of the above two events were quite different. K-means cluster classified their expression patterns into four clusters, and gene expression trends of clusters 1, 2 were similar in NAFLD and LR, while clusters 3, 4 were contrary with the gene expression changes of LR more abundant. DAVID classifications and functional enrichment analysis found that lipid metabolism and carbohydrate metabolism were stronger in NAFLD than in LR, but some other physiological activities including inflammation/immune response, cell adhesion, and migration, cell proliferation and differentiation in NAFLD were weaker than in LR. IPA further indicated that lipid metabolism, inflammation response, and cellular development were highly associated with NAFLD, and thus identified some potential biomarkers for NAFLD.

Analysis of the role of the integrin signaling pathway in hepatocytes during rat liver regeneration

To explore the role of the integrin signaling pathway in hepatocytes during rat liver regeneration, the integrin signaling pathway-related gene expression profile in hepatocytes of regenerative liver was detected using Rat Genome 230 2.0 array. The chip data showed that 265 genes of the integrin signaling pathway were included by Rat Genome 230 2.0 array and 132 genes showed significant expression changes in hepatocytes of regenerative liver. The numbers of up-, down- and up/down-regulated genes were 110, 15 and 7 respectively. In addition, bioinformatics and systems biology methods were used to analyze the role of the integrin signaling pathway in hepatocytes. The analysis of gene synergy value indicated that paths 1, 8, 12, and 15 promoted hepatocyte proliferation at the priming phase of liver regeneration; paths 1, 3, 8, and 12-15 enhanced hepatocyte proliferation at the progressing phase; paths 11 and 14 promoted hepatocyte proliferation, while paths 12 and 13 reduced hepatocyte proliferation at the terminal phase. Additionally, the other 8 paths (2, 4, 5-7, 9-10, and 16) were not found to be related to liver regeneration. In conclusion, 132 genes and 8 cascades of the integrin signaling pathway participated in regulating hepatocyte proliferation during rat liver regeneration.

Gap junction proteins: master regulators of the planarian stem cell response to tissue maintenance and injury

Gap junction (GJ) proteins are crucial mediators of cell-cell communication during embryogenesis, tissue regeneration and disease. GJ proteins form plasma membrane channels that facilitate passage of small molecules across cells and modulate signaling pathways and cellular behavior in different tissues. These properties have been conserved throughout evolution, and in most invertebrates GJ proteins are known as innexins. Despite their critical relevance for physiology and disease, the mechanisms by which GJ proteins modulate cell behavior are poorly understood. This review summarizes findings from recent work that uses planarian flatworms as a paradigm to analyze GJ proteins in the complexity of the whole organism. The planarian model allows access to a large pool of adult somatic stem cells (known as neoblasts) that support physiological cell turnover and tissue regeneration. Innexin proteins are present in planarians and play a fundamental role in controlling neoblast behavior. We discuss the possibility that GJ proteins participate as cellular sensors that inform neoblasts about local and systemic physiological demands. We believe that functional analyses of GJ proteins will bring a complementary perspective to studies that focus on the temporal expression of genes. Finally, integrating functional studies along with molecular genetics and epigenetic approaches would expand our understanding of cellular regulation in vivo and greatly enhance the possibilities for rationally modulating stem cell behavior in their natural environment. This article is part of a Special Issue entitled: The communicating junctions, roles and dysfunctions.

[Three novel genes BM390716, BI274487 and AA963863 involed in extracellular matrix metabolism of eight rat regenerating liver cell types]

To explore the roles of three novel genes BM390716, BI274487 and AA963863 and the correlation between them during liver regeneration of rats, eight kinds of liver cells were isolated using the combined percoll density gradient centrifugation and immunomagnetic bead method. Rat genome 230 2.0 array was used to detect the changes in expression of genes involved in metabolism of extracellular matrix and the novel genes in rat genome. Correlation between sequence homology, co-expression of the above genes and the physiological activities they involed in were analyzed using Microsoft Excel and BLAST software. The results showed that BM390716 was homologous to and co-expressed with pparα, BI274487 was homologous to and co-expressed with timp2, and AA963863 was homologous to and co-expressed with csgalnact1. It is predicted that BM390716, BI274487, and AA963863 were involved in extracellular matrix metabolism in eight types of rat regenerating liver cells.

Connexins: sensors and regulators of cell cycling

It is nowadays well established that gap junctions are critical gatekeepers of cell proliferation, by controlling the intercellular exchange of essential growth regulators. In recent years, however, it has become clear that the picture is not as simple as originally anticipated, as structural precursors of gap junctions can affect cell cycling by performing actions not related to gap junctional intercellular communication. Indeed, connexin hemichannels also foresee a pathway for cell growth communication, albeit between the intracellular compartment and the extracellular environment, while connexin proteins as such can directly or indirectly influence the production of cell cycle regulators independently of their channel activities. Furthermore, a novel set of connexin-like proteins, the pannexins, have lately joined in as regulators of the cell proliferation process, which they can affect as either single units or as channel entities. In the current paper, these multifaceted aspects of connexin-related signalling in cell cycling are reviewed.

[Transcriptome atlas of serine family amino acid metabolism-related genes in eight rat regenerating liver cell types.]

To explore the transcription profiles of serine family amino acid metabolism-related genes in eight liver cell types during rat liver regeneration (LR), eight types of rat regenerating liver cells were isolated using the combination of percoll density gradient centrifugation and immunomagnetic bead methods. Then, the expression profiles of the genes associated with metabolism of serine family amino acid in rat liver regeneration were detected by Rat Genome 230 2.0 Array. The expression patterns of these genes were analyzed through the software of Cluster and Treeview. The activities of serine family amino acid metabolism were analyzed by the methods of bioinformatics and systems biology. The results showed that 27 genes were significantly expressed. Among them, the numbers of genes showing significant expression changes in hepatocytes, biliary epithelial cells, oval cells, hepatic stellate cells, sinusoidal endothelial cells, Kupffer cells, pit cells and dendritic cells were 13, 16, 11, 14, 13, 11, 12, and 14, respectively. The numbers of up-, down-, and up-/down-regulated genes in corresponding cells were 7, 6, and 0; 2, 10, and 4; 2, 8, and 1; 8, 3, and 3; 6, 5, and 2; 4, 6, and 1; 2, 10, and 0; and 6, 6, and 2. Overall, the genes in the eight types of cells were mostly down-regulated during liver regeneration, but most LR-related genes in hepatic stellate cells and sinusoidal endothelial cells were up-regulated in priming phase. It is suggested that biosynthesis of serine family amino acid was enhanced in hepatocytes, hepatic stellate cells, sinusoidal endothelial cells and Kupffer cells in the priming phase. The catabolism of them was enhanced in hepatocytes, biliary epithelial cells, pit cells and dendritic cells in progressive phase.

Key genes and proteins involved in CTCM-reducing microvascular endothelial cell permeability induced by SLT-IIv using gene chips and DIGE

An Affymetrix mouse genome array and differential in-gel electrophoresis (DIGE) techniques were used to investigate the pharmacological mechanisms of a mixture of herbs, designated CTCM, a compound of traditional Chinese medicine, for the treatment of increased permeability in mouse intestinal microvascular endothelial cells (MIMECs) induced by the Shiga-like toxin type II variant (SLT-IIv). MIMECs were challenged with 10microg/ml SLT-IIv for 12h and then treated with CTCM at a concentration of 200microg/ml for 12h. Total RNA and proteins from each treatment group were extracted from cultured MIMECs for analysis by the Affymetrix GeneChip Mouse Genome 430 2.0 microarray and DIGE. The results obtained demonstrated that there were one genes downregulated and one genes upregulated, one protein downregulated and four proteins upregulated in the SLT-IIv group compared to the control group. In the CTCM group, four genes were upregulated, three genes were downregulated, a single protein was downregulated and a single protein was upregulated when compared to the control group. When the CTCM-treated group was compared to the SLT-IIv group, expression of one gene was found to be increased, and all other genes were decreased, with five proteins downregulated. Analysis of the data suggested that CTCM specifically and effectively reduced microvascular endothelial cell permeability to SLT-IIv in the treatment of pig edema disease. In the CTCM-treated group, hspa9 expression was increased in both gene chip and DIGE analysis, so it may be a key protein in reducing cell permeability and utilized in medical treatments.

Study on the antiendotoxin action of Pulsatillae Decoction using an Affymetrix rat genome array

A high-throughput and efficient Affymetrix rat genome array was used to investigate the pharmacological mechanism of the traditional Chinese medicine, Pulsatillae Decoction (PD), used for the treatment of diseases induced by lipopolysaccharide (LPS). Rat intestinal microvascular endothelial cells (RIMECs) were challenged with 1mug/ml LPS for 3h, and then treated with PD at a concentration of 1mg/ml for 24h. Total RNA from each treatment group was extracted from cultured RIMECs for detection by the Affymetrix Rat Genome 230 2.0 Array. The results showed that 36 genes were upregulated and 33 genes were downregulated in the LPS group vs. the blank control group; 566 genes were upregulated and 12 genes were downregulated in the PD-treated group vs. the LPS group; and 93 genes were upregulated and 29 genes were downregulated in the PD-treated group vs. the blank control group. The analysis of these data suggested that PD specifically and effectively reduce damage induced by LPS, and improved physiological and biochemical responses to counteract the effects of LPS.

Quantitative assessment of hepatic function and its relevance to the liver surgeon

BACKGROUND

Standard evaluation of patients undergoing hepatic surgery has been through radiological and quantitative determination of liver function. As more complex and extensive surgery is now being performed, often in the presence of cirrhosis/fibrosis or following administration of chemotherapy, it is questioned whether additional assessment may be required prior to embarking on such surgery. The aim of this review was to determine the current knowledge base in relation to the performance of quantitative assessment of hepatic function both pre- and post-operatively in patients undergoing hepatic resectional surgery and liver transplantation.

METHODS

An electronic search was performed of the medical literature using the MEDLINE database to identify relevant articles with cross-referencing of all identified papers to ensure full literature capture.

RESULTS AND CONCLUSIONS

The review has identified a number of different methods of dynamically assessing hepatic function, the most frequently performed being through the use of indocyanine green clearance. With the recent and further anticipated developments in hepatic resectional surgery, it is likely that quantitative assessment will become more widely practiced in order to reduce post-operative hepatic failure and improve outcome.