Matrix metalloproteinases-9 deficiency impairs liver regeneration through epidermal growth factor receptor signaling in partial hepatectomy mice

Discovery of an Heparin-Binding Epidermal Growth Factor Domain Antibody from a Phage Library and Analysis of Its Inhibitory Effects in SKOV3 Cells

Objective: Heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF), which binds to the EGF receptor, plays an important role in the occurrence and development of inflammation in various diseases. HB-EGF mediates the progression of ovarian cancer and is associated with disease prognosis. Thus, a specific humanized antibody to HB-EGF with high affinity is important. Methods: In this study, a humanized domain antibody (VH) against HB-EGF was discovered through phage display technology. The domain antibody was expressed in HB2151 cells and purified from the supernatant using protein L, and were used to test the its effect in invasion and migration of ovarian cancer SKOV3. Results: A domain antibody against HB-EGF was discovered, with a dissociation constant of ∼30 nM. Functional assays indicated that the domain antibody inhibited the functions of HB-EGF in promoting invasion and migration of SKOV3 cells. Conclusions: The selected domain antibody is a potential tool for developing novel drugs or therapies to combat ovarian cancer.

Relevance of EGFR Between Serum VEGF and MMP-9 in Primary Hepatocellular Carcinoma Patients with Transarterial Chemoembolization

Objective

The aim of this study was to estimate the relevance of the epidermal growth factor receptor (EGFR) between serum vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP-9) in primary hepatocellular carcinoma (HCC) patients with transarterial chemoembolization (TACE).

Methods

The pre-treatment and post-treatment concentrations of the serum VEGF and MMP‑9 were detected with Luminex assay in 80 EGFR-negative patients and 59 EGFR-positive patients who received TACE therapy with different chemotherapeutic drugs.

Results

The serum concentration of MMP-9 in the EGFR-positive patients with primary HCC was significantly higher than that in the EGFR-negative patients (P < 0.05). In EGFR-positive patients with primary HCC, differences in stage, metastasis, and differentiation were significant (P < 0.05). Serum VEGF level significantly decreased at the second course of treatment in the EGFR-negative patients from the P group (P < 0.05), while serum MMP-9 level significantly decreased at the second course of treatment in the EGFR-negative patients from the E group (P < 0.05). Serum VEGF level in the EGFR-positive patients among three groups slightly decreased at the first, second and third courses of treatments; however, the differences were not significant (P > 0.05). Serum MMP-9 level in the EGFR-positive patients among three groups showed mild decrease at the first and second courses of treatments; however, the decreases at the third course of treatment were significant (P < 0.05).

Conclusion

Serum VEGF and MMP-9 are potential biomarkers for the treatment monitoring of EGFR-positive and -negative patients after TACE therapy with different chemotherapeutic drugs.

B-Cell Activating Factor Enhances Hepatocyte-Driven Angiogenesis via B-Cell CLL/Lymphoma 10/Nuclear Factor-KappaB Signaling during Liver Regeneration

B-cell activating factor (BAFF) is found to be associated with the histological severity of nonalcoholic steatohepatitis (NASH). BAFF was also found to have a protective role in hepatic steatosis via down regulating the expression of steatogenesis genes and enhancing steatosis in hepatocytes through BAFF-R. However, the roles of BAFF during liver regeneration are not well defined. In this study, C57/B6 mice with 70% partial hepatectomy were used as a liver regeneration model. BAFF expression was determined by enzyme immunoassay, and anti-BAFF-neutralizing antibodies were administered to confirm the effects of BAFF on liver regeneration. Western blotting, immunohistochemistry, and florescence staining determined the expression of B-cell CCL/lymphoma 10 (BCL10). The angiogenesis promoting capability was evaluated after the transfection of cells with siRNA targeting BCL10 expression, and the role of NF-κB was assessed. The results revealed that the BAFF and BCL10 levels were upregulated after partial hepatectomy. Treatment with anti-BAFF-neutralizing antibodies caused death in mice that were subjected to 70% partial hepatectomy within 72 h. In vitro, recombinant BAFF protein did not enhance hepatocyte proliferation; however, transfection with BCL10 siRNA arrested hepatocytes at the G2/M phase. Interestingly, conditioned medium from BAFF-treated hepatocytes enhanced angiogenesis and endothelial cell proliferation. Moreover, Matrix metalloproteinase-9 (MMP-9), Fibroblast growth factor 4 (FGF4), and Interleukin-8 (IL-8) proteins were upregulated by BAFF through BCL10/NF-κB signaling. In mice that were treated with anti-BAFF-neutralizing antibodies, the microvessel density (MVD) of the remaining liver tissues and liver regeneration were both reduced. Taken together, our study demonstrated that an increased expression of BAFF and activation of BCL10/NF-κB signaling were involved in hepatocyte-driven angiogenesis and survival during liver regeneration.

Mechanosensing by β1 integrin induces angiocrine signals for liver growth and survival

Angiocrine signals derived from endothelial cells are an important component of intercellular communication and have a key role in organ growth, regeneration and disease^1-4. These signals have been identified and studied in multiple organs, including the liver, pancreas, lung, heart, bone, bone marrow, central nervous system, retina and some cancers^1-4. Here we use the developing liver as a model organ to study angiocrine signals^5,6, and show that the growth rate of the liver correlates both spatially and temporally with blood perfusion to this organ. By manipulating blood flow through the liver vasculature, we demonstrate that vessel perfusion activates β1 integrin and vascular endothelial growth factor receptor 3 (VEGFR3). Notably, both β1 integrin and VEGFR3 are strictly required for normal production of hepatocyte growth factor, survival of hepatocytes and liver growth. Ex vivo perfusion of adult mouse liver and in vitro mechanical stretching of human hepatic endothelial cells illustrate that mechanotransduction alone is sufficient to turn on angiocrine signals. When the endothelial cells are mechanically stretched, angiocrine signals trigger in vitro proliferation and survival of primary human hepatocytes. Our findings uncover a signalling pathway in vascular endothelial cells that translates blood perfusion and mechanotransduction into organ growth and maintenance.

Heparin-Binding Epidermal Growth Factor-Like Growth Factor as a Critical Mediator of Tissue Repair and Regeneration

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the EGF family. It contains an EGF-like domain as well as a heparin-binding domain that allows for interactions with heparin and cell-surface heparan sulfate. Soluble mature HB-EGF, a ligand of human epidermal growth factor receptors 1 and 4, is cleaved from the membrane-associated pro-HB-EGF by matrix metalloproteinase or a disintegrin and metalloproteinase in a process called ectodomain shedding. Signaling through human epidermal growth factor receptors 1 and 4 results in a variety of effects, including cellular proliferation, migration, adhesion, and differentiation. HB-EGF levels increase in response to different forms of injuries as well as stimuli, such as lysophosphatidic acid, retinoic acid, and 17β-estradiol. Because it is widely expressed in many organs, HB-EGF plays a critical role in tissue repair and regeneration throughout the body. It promotes cutaneous wound healing, hepatocyte proliferation after partial hepatectomy, intestinal anastomosis strength, alveolar regeneration after pneumonectomy, neurogenesis after ischemic injury, bladder wall thickening in response to urinary tract obstruction, and protection against ischemia/reperfusion injury to many cell types. Additionally, innovative strategies to deliver HB-EGF to sites of organ injury or to increase the endogenous levels of shed HB-EGF have been attempted with promising results. Harnessing the reparatory properties of HB-EGF in the clinical setting, therefore, may produce therapies that augment the treatment of various organ injuries.

Extracellular matrix remodeling and matrix metalloproteinases (ajMMP-2 like and ajMMP-16 like) characterization during intestine regeneration of sea cucumber Apostichopus japonicus

Remodeling of extracellular matrix (ECM) regulated by matrix metalloproteinases (MMPs) is essential for tissue regeneration. In the present study, we used immunohistochemistry (IHC) techniques against ECM components to reveal changes of ECM during intestine regeneration of Apostichopus japonicus. The expression of collagen I and laminin reduced apparently from the eviscerated intestine, while fibronectin exhibited continuous expression in all regeneration stages observed. Meanwhile, we cloned two MMP genes from A. japonicus by RACE PCR. The full-length cDNA of ajMMP-2 like is 2733bp and contains a predicted open reading frame (ORF) of 1716bp encoding 572 amino acids. The full-length cDNA of ajMMP-16 like is 2705bp and contains an ORF of 1452bp encoding 484 amino acids. The predicted protein sequences of each MMP contain two conserved domains, ZnMc_MMP and HX. Homology and phylogenetic analysis revealed that ajMMP-2 like and ajMMP-16 like share high sequence similarity with MMP-2 and MMP-16 from Strongylocentrotus purpuratus, respectively. Then we investigated spatio-temporal expression of ajMMP-2 like and ajMMP-16 like during different regeneration stages by qRT-PCR and IHC. The expression pattern of them showed a roughly opposite trend from that of ECM components. According to our results, a fibronectin-dominate temporary matrix is created in intestine regeneration, and it might provide structural integrity for matrix and promote cell movement. We also hypothesize that ajMMP-2 like and ajMMP-16 like could accelerate cell migration and regulate interaction between ECM components and growth factors. This work provides new evidence of ECM and MMPs involvement in sea cucumber regeneration.

Liver regeneration after partial hepatectomy

Liver regeneration after partial hepatectomy is an extremely complicated pathophysiologic process, which involves the up-regulation of many proliferation associated proteins and genes. The molecular mechanisms responsible for initiating, maintaining, and terminating this process are still under active investigation and remain one of the research focuses in the field of regenerative medicine. Studies of the mechanism of liver regeneration can provide a theoretical foundation for regeneration promotion and hepatic failure prevention, which is extremely important in clinical practice. This review aims to elucidate the molecular mechanism responsible for the initiation, proliferation and termination of liver regeneration.

MicroRNA-21 Contributes to Liver Regeneration by Targeting PTEN

Background

Multiple microRNAs (miRNAs, miRs), including miR-21, have been documented to be critical regulators of liver regeneration, but the mechanism underlying their roles in hepatocyte proliferation and cell cycle progression is still far from understood.

Material/Methods

miR-21 levels were determined using qRT-PCRs in mouse livers at 48 h after 70% partial hepatectomy (PH-48 h). Cell proliferation was determined by use of a cell-counting kit-8 (CCK-8), EdU incorporation staining, and flow cytometry. Phosphatase and tensin homolog (PTEN) expressions were determined using qRT-PCR and Western blot analysis. PTEN siRNA was used to perform the rescue experiment.

Results

A marked upregulation of miR-21 was observed in mouse livers at 48 h after 70% partial hepatectomy (PH-48 h) compared to 0 h after PH (PH-0 h). Overexpression of miR-21 was associated with increased proliferation and a rapid G1-to-S phase transition of the cell cycle in BNL CL.2 normal liver cells in vitro. In addition, we showed that PTEN expression was inversely correlated with miR-21 in BNL CL.2 cells and demonstrated that PTEN expression is lower in mouse livers at PH-48 h. Moreover, the presence of PTEN siRNA significantly abolished the suppressive effect of miR-21 inhibitor on hepatocyte proliferation.

Conclusions

miR-21 overexpression contributes to liver regeneration and hepatocyte proliferation by targeting PTEN. Upregulation of miR-21 might be a useful therapeutic strategy to promote liver regeneration.

EGFR Signaling in Liver Diseases

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase that is activated by several ligands leading to the activation of diverse signaling pathways controlling mainly proliferation, differentiation, and survival. The EGFR signaling axis has been shown to play a key role during liver regeneration following acute and chronic liver damage, as well as in cirrhosis and hepatocellular carcinoma (HCC) highlighting the importance of the EGFR in the development of liver diseases. Despite the frequent overexpression of EGFR in human HCC, clinical studies with EGFR inhibitors have so far shown only modest results. Interestingly, a recent study has shown that in human HCC and in mouse HCC models the EGFR is upregulated in liver macrophages where it plays a tumor-promoting function. Thus, the role of EGFR in liver diseases appears to be more complex than what anticipated. Further studies are needed to improve the molecular understanding of the cell-specific signaling pathways that control disease development and progression to be able to develop better therapies targeting major components of the EGFR signaling network in selected cell types. In this review, we compiled the current knowledge of EGFR signaling in different models of liver damage and diseases, mainly derived from the analysis of HCC cell lines and genetically engineered mouse models (GEMMs).

Systems analysis of non-parenchymal cell modulation of liver repair across multiple regeneration modes

Background

A hallmark of chronic liver disease is the impairment of the liver’s innate regenerative ability. In this work we use a computational approach to unravel the principles underlying control of liver repair following an acute physiological challenge.

Methods

We used a mathematical model of inter- and intra-cellular interactions during liver regeneration to infer key molecular factors underlying the dysregulation of multiple regeneration modes, including delayed, suppressed, and enhanced regeneration. We used model analysis techniques to identify organizational principles governing the cellular regulation of liver regeneration. We fit our model to several published data sets of deficient regeneration in rats and healthy regeneration in humans, rats, and mice to predict differences in molecular regulation in disease states and across species. 

Results

Analysis of the computational model pointed to an important balance involving inflammatory signals and growth factors, largely produced by Kupffer cells and hepatic stellate cells, respectively. Our model analysis results also indicated an organizational principle of molecular regulation whereby production rate of molecules acted to induce coarse-grained control of signaling levels while degradation rate acted to induce fine-tuning control. We used this computational framework to investigate hypotheses concerning molecular regulation of regeneration across species and in several chronic disease states in rats, including fructose-induced steatohepatitis, alcoholic steatohepatitis, toxin-induced cirrhosis, and toxin-induced diabetes. Our results indicate that altered non-parenchymal cell activation is sufficient to explain deficient regeneration caused by multiple disease states. We also investigated liver regeneration across mammalian species. Our results suggest that non-invasive measures of liver regeneration taken at 30 days following resection could differentiate between several hypotheses about how human liver regeneration differs from rat regeneration.

Conclusions

Overall, our results provide a new computational platform integrating a wide range of experimental information, with broader utility in exploring the dynamic patterns of liver regeneration across species and over multiple chronic diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12918-015-0220-9) contains supplementary material, which is available to authorized users.