No abstract

These data provide useful information on the global gene expression changes due to high-fat emulsion feeding and bring important insights into the mechanisms of NAFLD.

After partial hepatectomy (PH), the recovery of liver mass is mainly mediated by proliferation and enlargement of hepatocytes. Therefore, measuring the transcriptional profiling of hepatocytes after PH will be helpful in exploring the mechanism of liver regeneration (LR). Firstly, hepatocytes were isolated from rat regenerating liver at different time points following PH, and then global gene expression analysis of hepatocytes was performed using Rat Genome 230 2.0 Array. The results demonstrated that 1,417 genes in the array (including 767 known genes) were identified to be LR-related. Clustering analysis demonstrated that 767 known genes fell into six classes with distinct expression kinetics. When gene expression patterns were combined with gene functions, genes involved in acute-phase response and defense response were rapidly elevated in early phases; those in cell proliferation and DNA replication were significantly up-expressed in middle phase; a growing number of cell adhesion-involved genes were up-regulated as regeneration progressed; those in amino acid and lipid metabolism showed persistent down-regulation during LR. Based on the above analyses, it was suggested that hepatocyte defense mechanism was quickly triggered after PH; cell proliferation became active in middle phase; cell adhesion was strengthened in late phase; amino acid and lipid metabolism were attenuated during LR. Additionally, comparative analysis between transcriptional profiling of hepatocytes and regenerating liver indicated a major contribution of hepatocytes to LR.

The planarian Dugesia japonica has amazing ability to regenerate a head from the anterior ends of the amputated stump with maintenance of the original anterior-posterior polarity. Although planarians present an attractive system for molecular investigation of regeneration and research has focused on clarifying the molecular mechanism of regeneration initiation in planarians at transcriptional level, but the initiation mechanism of planarian head regeneration (PHR) remains unclear at the protein level. Here, a global analysis of proteome dynamics during the early stage of PHR was performed using isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics strategy, and our data are available via ProteomeXchange with identifier PXD002100. The results showed that 162 proteins were differentially expressed at 2 h and 6 h following amputation. Furthermore, the analysis of expression patterns and functional enrichment of the differentially expressed proteins showed that proteins involved in muscle contraction, oxidation reduction and protein synthesis were up-regulated in the initiation of PHR. Moreover, ingenuity pathway analysis showed that predominant signaling pathways such as ILK, calcium, EIF2 and mTOR signaling which were associated with cell migration, cell proliferation and protein synthesis were likely to be involved in the initiation of PHR. The results for the first time demonstrated that muscle contraction and ILK signaling might played important roles in the initiation of PHR at the global protein level. The findings of this research provide a molecular basis for further unraveling the mechanism of head regeneration initiation in planarians.

Abstract: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.

Osteopontin (OPN) is a member of Th1 cytokine secreted by activated lymphocytes and macrophages. However, it deserves to be studied whether OPN could promote cell activation or proliferation, and then facilitate hepatic self-repair during liver regeneration (LR). This study is designed to further reveal the effects of OPN on LR in vivo. Firstly, quantitative reverse transcription-PCR (qRT-PCR) and western blot (WB) were utilized to validate the expression profile of endogenous OPN in rat regenerating livers after partial hepatectomy (PH). Then OPN expression vector, two shRNA expression vectors and their respective test vectors were successfully constructed. Afterwards, test vectors were administrated into mouse livers via tail vein to find the more efficient shRNA. Furthermore, OPN expression vector and the more efficient shRNA expression vector were injected into rat regenerating livers, and then the changes in liver regeneration and hepatic microstructure were respectively detected by liver regeneration rate and HE staining, while the expressions of several marker genes were detected by qRT-PCR and WB. Endogenous OPN was strikingly up-regulated in both mRNA and protein level during LR, especially at 12 and 72 h after PH. The shRNA expression vector Opn(313) was found to be more efficient than Opn(887) in silencing the expression of Opn. Then OPN expression vector and Opn(313) were injected into rat remnant livers, and it showed that OPN overexpression aggravated hepatic necrosis and leukocytes infiltration, while OPN silencing inhibited liver regeneration rate and the expressions of PCNA and CCL2, but augmented that of BAX. In conclusion, OPN might enhance inflammation and cell proliferation, attenuate cell apoptosis, and ultimately facilitate liver regeneration at the termination stage of liver regeneration.

Chang (2019) An integrated analysis of the circRNA-miRNA-mRNA network reveals novel insights into potential mechanisms of cell proliferation during liver regeneration,

Serine peptidase inhibitor Kazal type I (SPINK1) has the similar spatial structure as epidermal growth factor (EGF); EGF can interact with epidermal growth factor receptor (EGFR) to promote proliferation in different cell types. However, whether SPINK1 can interact with EGFR and further regulate the proliferation of hepatocytes in liver regeneration remains largely unknown. In this study, we investigated the role of SPINK1 in a rat liver hepatocyte line of BRL-3A in vitro. The results showed the upregulation of endogenous Spink1 (gene addition) significantly increased not only the cell viability, cell numbers in S and G /M phase, but also upregulated the genes/proteins expression related to cell proliferation and anti-apoptosis in BRL-3A. In contrast, the cell number in G phase and the expression of pro-apoptosis-related genes/proteins were significantly decreased. The similar results were observed when the cells were treated with exogenous rat recombinant SPINK1. Immunoblotting suggested SPINK1 can interact with EGFR. By Ingenuity Pathway Analysis software, the SPINK1 signalling pathway was built; the predicted read outs were validated by qRT-PCR and western blot; and the results showed that p38, ERK, and JNK pathways-related genes/proteins were involved in the cell proliferation upon the treatment of endogenous Spink1 and exogenous SPINK1. Collectively, SPINK1 can associate with EGFR to promote the expression of cell proliferation-related and anti-apoptosis-related genes/proteins; inhibit the expression of pro-apoptosis-related genes/proteins via p38, ERK, and JNK pathways; and consequently promote the proliferation of BRL-3A cells. For the first time, we demonstrated that SPINK1 can associate with EGFR to promote the proliferation of BRL-3A cells via p38, ERK, and JNK pathways. This work has direct implications on the underlying mechanism of SPINK1 in regulating hepatocytes proliferation in vivo and liver regeneration after partial hepatectomy.