Liver Epithelial Cells Research Articles

Heterogeneity and chimerism of endothelial cells revealed by single-cell transcriptome in orthotopic liver tumors

The liver is a common host organ for cancer, either through lesions that arise in liver epithelial cells [e.g., hepatocellular carcinoma (HCC)] or as a site of metastasis by tumors arising in other organs (e.g., colorectal cancer). However, the changes that occur in liver stromal cells in response to cancer have not been fully characterized, nor has it been determined whether the different sources of liver cancer induce distinct stromal changes. Here, we performed single-cell profiling of liver stromal cells from mouse models of induced spontaneous liver cancer or implanted colorectal liver metastases, with a focus on tumor endothelial cells (ECs). While ECs in liver tissue adjacent to cancerous lesions (so-called adjacent normal) corresponded to liver zonation phenotypes, their transcriptomes were also clearly altered by the presence of a tumor. In comparison, tumor EC transcriptomes show stronger similarities to venous than sinusoidal ECs. Further, tumor ECs, independent of tumor origin, formed distinct clusters displaying conserved “tip-like” or “stalk-like” characteristics, similar to ECs from subcutaneous tumors. However, they also carried liver-specific signatures found in normal liver ECs, suggesting an influence of the host organ on tumor ECs. Our results document gene expression signatures in ECs in liver cancer and show that the host organ, and not the site of tumor origin (liver versus colorectal), is a primary determinant of EC phenotype. In addition, primarily in tumors, we further defined a cluster of chimeric cells that expressed both myeloid and endothelial cell markers and might play a role in tumor angiogenesis.

Assessment of diagnostic biomarkers of liver injury in the setting of microcystin-LR (MC-LR) hepatotoxicity

Microcystin-leucine arginine (MC-LR) is a potent liver toxin produced by freshwater cyanobacteria, also known as blue-green algae. While harmful algal blooms are increasing in frequency and severity worldwide, there is still no established method for the diagnosis and assessment of MC-LR induced liver damage. The guidelines for MC-LR safe exposure limits have been previously established based on healthy animal studies, however we have previously demonstrated that pre-existing non-alcoholic fatty liver disease (NAFLD) increases susceptiblity to the hepatotoxic effects of MC-LR. In this study, we sought to investigate the suitability of clinically used biomarkers of liver injury, specifically alanine aminotransferase (ALT) and alkaline phosphatase (ALP), as potential diagnostic tools for liver damage induced by chronic low dose administration of MC-LR in the setting of pre-existing NAFLD. In our Leprdb/J mouse model of NAFLD, we found that while MC-LR induced significant histopathologic damage in the setting of NAFLD, gene expression of ALT and ALP failed to increase with MC-LR exposure. Serum ALT and ALP also failed to increase with MC-LR exposure, except for a moderate increase in ALP with the highest dose of MC-LR used (100 μg/kg). In HepG2 human liver epithelial cells, we observed that increasing MC-LR exposure levels do not lead to an increase in ALT or ALP gene expression, intracellular enzyme activity, or extracellular activity, despite a significant increase in MC-LR induced cytotoxicity. These findings demonstrate that ALT and ALP may be unsuitable as diagnostic biomarkers for MC-LR induced liver damage.

IFN-lambda 3 directly induces antiviral responses in human B and T cells leading to inhibition of HIV-1 infection of CD4+ T cells

Abstract Type III interferons (IFN-lambdas(λ)) are the most recently discovered interferon cytokine family that inhibit viruses by signaling through a unique IFN-λR1/IL-10RB heterodimeric receptor. Until now, IFN-λs were thought to primarily act on anatomical barrier epithelial cells, neutrophils and a subset of dendritic cells, although the majority of studies have been performed in mice. Here, we examine regulation of IFN-λR1 expression and downstream effects of IFN-λ3 stimulation of primary human blood immune cells and compare them to lung or liver epithelial cells. IFN-λ3 directly bound and upregulated IFN-stimulated gene (ISG) expression in freshly purified human B cells and CD8+ T cells, but not monocytes, neutrophils, natural killer cells and CD4+ T cells. Despite similar IFNLR1 transcript levels in B cells and lung epithelial cells, lung epithelial cells bound more IFN-λ3, which resulted in a 50-fold greater ISG induction when compared to B cells. The reduced response of B cells could be explained by the higher expression of the soluble splice variant of IFN-λR1, which inhibited ISG induction when added with IFN-λ3 to peripheral blood mononuclear cells. Human CD4+ T cells gained responsiveness to IFN-λ3 upon T-cell receptor stimulation since activation signals potently, and specifically upregulated membrane-bound IFN-λR1 expression. Importantly, IFN-λ3 treatment of activated CD4+ T cells caused a significant decrease in human immunodeficiency virus-1 (HIV-1) infection. Collectively, our data demonstrate that IFN-λ3 directly interacts with the human adaptive immune system, and thus can promote antiviral immunity at mucosal and peripheral sites, unlike what has been previously shown in published mouse models.

Differential expression of interferon-lambda receptor 1 splice variants determines the magnitude of the antiviral response induced by interferon-lambda 3 in human immune cells.

Type III interferons (IFN-lambdas(λ)) are important cytokines that inhibit viruses and modulate immune responses by acting through a unique IFN-λR1/IL-10RB heterodimeric receptor. Until now, the primary antiviral function of IFN-λs has been proposed to be at anatomical barrier sites. Here, we examine the regulation of IFN-λR1 expression and measure the downstream effects of IFN-λ3 stimulation in primary human blood immune cells, compared with lung or liver epithelial cells. IFN-λ3 directly bound and upregulated IFN-stimulated gene (ISG) expression in freshly purified human B cells and CD8+ T cells, but not monocytes, neutrophils, natural killer cells, and CD4+ T cells. Despite similar IFNLR1 transcript levels in B cells and lung epithelial cells, lung epithelial cells bound more IFN-λ3, which resulted in a 50-fold greater ISG induction when compared to B cells. The reduced response of B cells could be explained by higher expression of the soluble variant of IFN-λR1 (sIFN-λR1), which significantly reduced ISG induction when added with IFN-λ3 to peripheral blood mononuclear cells or liver epithelial cells. T-cell receptor stimulation potently, and specifically, upregulated membrane-bound IFNLR1 expression in CD4+ T cells, leading to greater antiviral gene induction, and inhibition of human immunodeficiency virus type 1 infection. Collectively, our data demonstrate IFN-λ3 directly interacts with the human adaptive immune system, unlike what has been previously shown in published mouse models, and that type III IFNs could be potentially utilized to suppress both mucosal and blood-borne viral infections.

Loss of c-Jun N-terminal Kinase 1 and 2 Function in Liver Epithelial Cells Triggers Biliary Hyperproliferation Resembling Cholangiocarcinoma.

Targeted inhibition of the c‐Jun N‐terminal kinases (JNKs) has shown therapeutic potential in intrahepatic cholangiocarcinoma (CCA)‐related tumorigenesis. However, the cell‐type‐specific role and mechanisms triggered by JNK in liver parenchymal cells during CCA remain largely unknown. Here, we aimed to investigate the relevance of JNK1 and JNK2 function in hepatocytes in two different models of experimental carcinogenesis, the dethylnitrosamine (DEN) model and in nuclear factor kappa B essential modulator (NEMO)hepatocyte‐specific knockout (Δhepa) mice, focusing on liver damage, cell death, compensatory proliferation, fibrogenesis, and tumor development. Moreover, regulation of essential genes was assessed by reverse transcription polymerase chain reaction, immunoblottings, and immunostainings. Additionally, specific Jnk2 inhibition in hepatocytes of NEMOΔhepa/JNK1Δhepa mice was performed using small interfering (si) RNA (siJnk2) nanodelivery. Finally, active signaling pathways were blocked using specific inhibitors. Compound deletion of Jnk1 and Jnk2 in hepatocytes diminished hepatocellular carcinoma (HCC) in both the DEN model and in NEMOΔhepa mice but in contrast caused massive proliferation of the biliary ducts. Indeed, Jnk1/2 deficiency in hepatocytes of NEMOΔhepa (NEMOΔhepa/JNKΔhepa) animals caused elevated fibrosis, increased apoptosis, increased compensatory proliferation, and elevated inflammatory cytokines expression but reduced HCC. Furthermore, siJnk2 treatment in NEMOΔhepa/JNK1Δhepa mice recapitulated the phenotype of NEMOΔhepa/JNKΔhepa mice. Next, we sought to investigate the impact of molecular pathways in response to compound JNK deficiency in NEMOΔhepa mice. We found that NEMOΔhepa/JNKΔhepa livers exhibited overexpression of the interleukin‐6/signal transducer and activator of transcription 3 pathway in addition to epidermal growth factor receptor (EGFR)‐rapidly accelerated fibrosarcoma (Raf)‐mitogen‐activated protein kinase kinase (MEK)‐extracellular signal‐regulated kinase (ERK) cascade. The functional relevance was tested by administering lapatinib, which is a dual tyrosine kinase inhibitor of erythroblastic oncogene B‐2 (ErbB2) and EGFR signaling, to NEMOΔhepa/JNKΔhepa mice. Lapatinib effectively inhibited cystogenesis, improved transaminases, and effectively blocked EGFR‐Raf‐MEK‐ERK signaling. Conclusion: We define a novel function of JNK1/2 in cholangiocyte hyperproliferation. This opens new therapeutic avenues devised to inhibit pathways of cholangiocarcinogenesis.

Effects of Compound Active Peptides on Protecting Liver and Intestinal Epithelial Cells from Damages and Preventing Hyperglycemia.

Active peptides have good effectiveness in controlling or preventing many diseases. Compound active peptides (CAP) obtained from animal, plant, and sea food proteins were used in this study to explore their effects on antioxidation, anti-inflammation, and antihyperglycemia in vitro and in vivo. The results demonstrated that 10 μg/mL CAP could increase cell viability (P < 0.05) and decrease reactive oxygen species (ROS) levels and cell apoptosis (P < 0.05) when WRL68 cells were induced by H2O2 for 6 h. Moreover, incubation with 20 μg/mL CAP for 6 h significantly increased cell viability and Bcl-2 expression level (P < 0.05) and decreased expression levels of IL-6, IL-8, TNF-α, Bax, and Caspase 3 and the ratio of Bax/Bcl-2 (P < 0.05) when swine jejunal epithelial cells (IPEC-J2) were induced by deoxynivalenol (DON). In addition, adding CAP individually or combined with Liuweidihuang pills (LDP, Chinese medicine) and low-dose glibenclamide could lower blood glucose levels in alloxan-induced hyperglycemic model mice. These results suggested that CAP was probably a beneficial ingredient for alleviating H2O2-induced oxidative stress and DON-induced cell inflammation and apoptosis and preventing hyperglycemia.

Elevated PDK1 Expression Drives PI3K/AKT/MTOR Signaling Promotes Radiation-Resistant and Dedifferentiated Phenotype of Hepatocellular Carcinoma.

Resistance to radiotherapy (IR), with consequent disease recurrence, continues to limit the efficacy of contemporary anticancer treatment for patients with hepatocellular carcinoma (HCC), especially in late stage. Despite accruing evidence implicating the PI3K/AKT signaling pathway in cancer-promoting hypoxia, cancerous cell proliferation and radiotherapy-resistance, it remains unclear which molecular constituent of the pathway facilitates adaptation of aggressive HCC cells to tumoral stress signals and drives their evasion of repeated IR-toxicity. This present study investigated the role of PDK1 signaling in IR-resistance, enhanced DNA damage repair and post-IR relapse, characteristic of aggressive HCC cells, while exploring potential PDK1-targetability to improve radiosensitivity. The study employed bioinformatics analyses of gene expression profile and functional protein–protein interaction, generation of IR-resistant clones, flow cytometry-based ALDH activity and side-population (SP) characterization, siRNA-mediated loss-of-PDK1function, western-blotting, immunohistochemistry and functional assays including cell viability, migration, invasion, clonogenicity and tumorsphere formation assays. We showed that the aberrantly expressed PDK1 characterizes poorly differentiated HCC CVCL_7955, Mahlavu, SK-HEP1 and Hep3B cells, compared to the well-differentiated Huh7 or normal adult liver epithelial THLE-2 cells, and independently activates the PI3K/AKT/mTOR signaling. Molecular ablation of PDK1 function enhanced susceptibility of HCC cells to IR and was associated with deactivated PI3K/AKT/mTOR signaling. Additionally, PDK1-driven IR-resistance positively correlated with activated PI3K signaling, enhanced HCC cell motility and invasiveness, augmented EMT, upregulated stemness markers ALDH1A1, PROM1, SOX2, KLF4 and POU5F1, increased tumorsphere-formation efficiency and suppressed biomarkers of DNA damage—RAD50, MSH3, MLH3 and ERCC2. Furthermore, the acquired IR-resistant phenotype of Huh7 cells was strongly associated with significantly increased ALDH activity, SP-enrichment, and direct ALDH1-PDK1 interaction. Moreover, BX795-mediated pharmacological inhibition of PDK1 synergistically enhances the radiosensitivity of erstwhile resistant cells, increased Bax/Bcl-2 apoptotic ratio, while suppressing oncogenicity and clonogenicity. We provide preclinical evidence implicating PDK1 as an active driver of IR-resistance by activation of the PI3K/AKT/mTOR signaling, up-modulation of cancer stemness signaling and suppression of DNA damage, thus, projecting PDK1-targeting as a putative enhancer of radiosensitivity and a potential new therapeutic approach for patients with IR-resistant HCC.

HIV-1: towards understanding the nature and quantifying the latent reservoir.

The human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) pandemic constitutes one of the greatest public health issues, since 36.9 million people worldwide were living with HIV in 2017 and 940,000 died from AIDS- related illnesses in the same year. One of the main obstacles in the effort to achieve viral eradication or long-term virologic remission is the existence of the HIV-reservoir. Except for resting memory CD4+ T cells there is a plethora of innate immunity cells including macrophages, dendritic cells, follicular T helper cells and NK cells which are now considered to play a role in viral latency and persistence. Hematopoietic precursor cells and progenitor mast cells, astrocytes, fibrocytes, renal and liver epithelial cells could also contribute to the reservoir, but their role remains controversial. Tissue reservoirs, such as the central nervous system (CNS), lymphoid tissue, adipose tissue and the gut-associated-lymphoid-tissue (GALT) are usually referred to as anatomic sanctuaries, where it is difficult to achieve high concentration and efficacy of antiretroviral agents. Accurate quantification of this reservoir is of the utmost importance and multiple assays have been developed for this purpose. The role of several cell populations in viral latency needs to be clarified by further studies. Furthermore, there is an urgent need for new assays, which will accurately measure the size of the reservoir, which plays a key role in predicting the timing of viral rebound upon cessation of antiretroviral treatment, since the currently available ones either overestimate or underestimate the size and have significant limitations. Keywords: HIV-1; cellular reservoirs; tissue reservoirs; quantification.

Hyperglycemia induces key genetic and phenotypic changes in human liver epithelial HepG2 cells which parallel the Leprdb/J mouse model of non-alcoholic fatty liver disease (NAFLD).

Non-alcoholic fatty liver disease (NAFLD) is a growing global health concern. With a propensity to progress towards non-alcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma, NAFLD is an important link amongst a multitude of comorbidities including obesity, diabetes, and cardiovascular and kidney disease. As several in vivo models of hyperglycemia and NAFLD are employed to investigate the pathophysiology of this disease process, we aimed to characterize an in vitro model of hyperglycemia that was amenable to address molecular mechanisms and therapeutic targets at the cellular level. Utilizing hyperglycemic cell culturing conditions, we induced steatosis within a human hepatocyte cell line (HepG2 cells), as confirmed by electron microscopy. The deposition and accumulation of lipids within hyperglycemic HepG2 cells is significantly greater than in normoglycemic cells, as visualized and quantified by Nile red staining. Alanine aminotransferase (ALT) and alkaline phosphatase (ALP), diagnostic biomarkers for liver damage and disease, were found to be upregulated in hyperglycemic HepG2 cells as compared with normoglycemic cells. Suppression of CEACAM1, GLUT2, and PON1, and elevation of CD36, PCK1, and G6PK were also found to be characteristic in hyperglycemic HepG2 cells compared with normoglycemic cells, suggesting insulin resistance and NAFLD. These in vitro findings mirror the characteristic genetic and phenotypic profile seen in Leprdb/J mice, a well-established in vivo model of NAFLD. In conclusion, we characterize an in vitro model displaying several key genetic and phenotypic characteristics in common with NAFLD that may assist future studies in addressing the molecular mechanisms and therapeutic targets to combat this disease.

Circ_0091579 promotes proliferative ability and metastasis of liver cancer cells by regulating microRNA-490-3p.

To explore the role of Circular RNA 0091579 in the progression of liver cancer (LCa) and its molecular mechanism. Quantitative polymerase chain reaction (qPCR) was used to detect circ_0091579 expression levels in LCa tissues and adjacent tissues, which was further verified in LCa cells and normal liver epithelial cells. After circ_0091579 was knocked down in Huh7 and HepG2 cells, cell counting kit-8 (CCK-8), plate cloning and transwell assays were performed to verify the effect of circ_0091579 on cell proliferative ability and metastasis of LCa cells. The starBase database was used to search for microRNAs that could interact with circ_0091579, and the Dual-Luciferase reporter gene was used to verify their binding relationship. circ_0091579 was highly expressed in HCC and HCC cells. In vitro experiments showed that down-regulation of circ_0091579 expression could remarkably inhibit the proliferative ability and metastasis of HCC cells. Bioinformatics software predicted the binding sites between circ_0091579 and microRNA-490-3p, and dual-luciferase reporter gene assay confirmed the binding relationship between circ_0091579 and microRNA-490-3p. qPCR results showed that microRNA-490-3p was remarkably down-regulated in LCa tissues. In vitro experiments confirmed that overexpression of microRNA-490-3p inhibited the proliferative ability and metastasis of HCC cells. circ_0091579 is abnormally highly expressed in LCa tissues and cells. Down-regulation of circ_0091579 can inhibit the proliferative ability and metastasis of HCC cells by regulating microRNA-490-3p, thus accelerating the progress of the tumor.

LncRNA RP11-422N16.3 Inhibits Cell Proliferation and EMT, and Induces Apoptosis in Hepatocellular Carcinoma Cells by Sponging miR-23b-3p.

ObjectiveThis study investigated the mechanism of RP11-422N16.3 sponging miR-23b-3p in cell proliferation, apoptosis and epithelial-mesenchymal transition (EMT) in liver cancer.MethodsExpressions of RP11-422N16.3, miR-23b-3p and dimethylglycine dehydrogenase (DMGDH) were determined in liver cancer tissues, adjacent normal tissues, hepatocellular carcinoma cell lines and normal liver epithelial cell line. Up-regulation of RP11-422N16.3 and down-regulation of miR-23b-3p were conducted in hepatocellular carcinoma cells. Bioinformatics analysis, luciferase reporter assay and RNA-pull down assay were performed to verify the relationship among miR-23b-3p, DMGDH, as well as RP11-422N16.3. Cell proliferation and cell apoptosis were determined by CCK-8 and Flow Cytometry analysis, respectively.ResultsExpressions of RP11-422N16.3 and DMGDH were down-regulated while that of miR-23b-3p were up-regulated in hepatocellular carcinoma cancer tissues and cells. RP11-422N16.3 localized in cytoplasm and competitively bound to miR-23b-3p. Up-regulation of RP11-422N16.3 and down-regulation of miR-23b-3p contributed to increased expressions of DMGDH and E-cadherin, and decreased expressions of miR-23b-3p, ZEB1, Snail and Vimentin, resulting in inhibiting cell proliferation and promoting cell apoptosis. Inhibition of RP11-422N16.3 or overexpression of miR-23b-3p accelerated cell proliferation and slowed down cell apoptosis. miR-23b-3p inhibited the expression of DMGDH.ConclusionOur data suggested that LncRNA RP11-422N16.3, by competitively binding to miR-23b-3p, promoted DMGDH expression, contributing to inhibit cell proliferation and EMT, and induce cell apoptosis in hepatocellular carcinoma cells.

Targeting AML: The Development of Two Functionally and Mechanistically Distinct Classes of Cereblon-Mediated Protein Homeostatic Modulators

Targeting disease-relevant proteins by exploiting the cells' very own protein homeostasis machinery is the next generation drug discovery platform that has come center stage for treatment of hematological malignancies. We present our novel and unique Protein Homeostatic Modulators (PHMsTM) - that promote ubiquitination and subsequent proteasomal degradation of known substrates as well as neosubstrates via Cereblon - as therapeutic candidates for acute myeloid leukemia (AML). Specifically, we report the discovery of two functionally and mechanistically distinct classes of Cereblon-mediated PHMsTM from phenotypic screens of our proprietary PHM®library. Unlike classical IMiDs, our oncology candidates, BTX508 and BTX1119 demonstrate significant cytotoxicity with IC50s in low-nanomolar range in a panel of AML cell lines. BTX508 is a purely cytotoxic compound that does not display immune modulatory activity. In contrast, BTX1119 is not only cytotoxic, but is also immunomodulatory in that it inhibits inflammatory cytokines such as IL-1β, IL-6 and TNF-α as well as induces IL-2, an indicator of T cell activation. BTX1119's immune modulatory activity is a 100-fold more potent when compared to Pomalidomide. The distinct functional activities exhibited by BTX508 and BTX1119 is a result of strategically engineered substrate degradation profiles. Importantly, BTX508 and BTX1119 exhibit a large safety window wherein the concentrations at which they target AML cells do not affect normal healthy cells such as liver epithelial cells or lung fibroblasts. To further establish BTX508 as a clinical candidate for AML, we performed in vivo efficacy studies in the MV-4-11 human AML xenograft model using athymic nude mice. A single daily dose of BTX508 results in a significant reduction in tumor volume. BTX508 exhibits significant oral bioavailability, thus making it a promising clinical candidate for treatment of AML as well as other potential hematological malignancies. With regard to BTX1119, we believe that incorporation of both the potent cytotoxic and immunomodulatory properties into a single molecule holds great therapeutic promise; however, to evaluate the synergistic potential of this combination will require use of a humanized mouse model - this work is ongoing. Disclosures No relevant conflicts of interest to declare.

Activity and mechanism of flavokawain A in inhibiting P-glycoprotein expression in paclitaxel resistance of lung cancer.

Lung cancer is one of the most common cancers, which is the leading cause of cancer-related death among various cancers worldwide. Flavokawain A (FKA), a chalcone found in the kava plant, exerts potent anticancer activity. However, the activity and mechanisms of FKA in inhibiting the viability of paclitaxel (PTX)-resistant lung cancer A549 (A549/T) have not been investigated. In the present study, the effect of FKA on the viability of A549/T and hepatotoxicity in normal liver epithelial cells was detected by Cell Counting Kit-8 assay. Flow cytometry, western blot analysis and Annexin V-FITC/PI apoptosis detection kit were used to assess cell apoptosis. The effect of FKA on permeability-glycoprotein (P-gp) expression was measured by reverse transcription-PCR and western blot analysis. The results indicated that FKA dose-dependently inhibited cell proliferation and induced cell apoptosis in PTX-resistant A549/T cells, with an IC50 value of ~21 µM, while the IC50 value of A549/T cells to PTX was 34.64 µM. FKA had no hepatic toxicity in liver epithelial cells. P-gp, which contributes to the chemoresistant phenotype, was not expressed in A549 cells but was remarkably enhanced in A549/T cells. FKA (30 µM) decreased P-gp protein expression at 24 h by 3-fold. Furthermore, FKA downregulated P-gp expression by blocking the PI3K/Akt pathway. These findings suggest FKA as a potential candidate for the treatment of PTX-resistant lung cancer.

Methylisothiazolinone induces apoptotic cell death via matrix metalloproteinase activation in human bronchial epithelial cells

Methylisothiazolinone (MIT) has been used in wide spectrum of fields due to its ability to inhibit microbial proliferation with low toxicity. Meanwhile, in Korea, the concern about the hazardous effects of MIT was amplified by the occurrence of patients that have humidifier disinfectant-associated pulmonary disease. However, the toxic mechanism for the pathological lesion is still unclear. In our previous study, we identified that cell viability decreased more rapidly in bronchial epithelial cells (BEAS-2B cells) compared to keratinocytes and liver epithelial cells under the same exposure condition. In this study we demonstrated that MIT (2, 4 and 8 μg/mL) induced dose-dependent cytotoxicity 24 h after exposure to BEAS-2B cells. Additionally, MIT impaired structure and function of intracellular organelles via oxidative stress, ultimately leading to apoptotic cell death. We also found notable activation of matrix metalloproteinases (MMPs) and clear aggregation of nucleolus proteins in MIT-treated cells. Furthermore, MIT increased secretion of proinflammatory cytokines (Interleukin (IL)-1β, IL-6, and interferon-γ) and a chemokine (IL-8), and microarray and the KEGG pathway analysis proposed possible carcinogenesis following exposure to MIT. Taken together, we conclude that MIT induces apoptotic cell death and inflammatory response by activating MMPs in BEAS-2B cells. We also suggest that further study is necessary to clarify the possible carcinogenesis of MIT.

Transforming growth factor-β signaling confers hepatic stellate cells progenitor features after partial hepatectomy.

Liver regeneration involves not only hepatocyte replication but progenitor aggregation and scarring. Partial hepatectomy (PH), an established model for liver regeneration, reactivates transforming growth factor-β (TGF-β) signaling. Hepatic stellate cells (HSCs) are primarily responding cells for TGF-β and resident in stem cell niche. In the current study, PH mice were treated with SB-431542, an inhibitor of TGF-β Type I receptor, aiming to address the role of TGF-β signaling on the fate determination of HSCs during liver regeneration. After PH, control mice exhibited HSCs activation, progenitor cells accumulation, and a fraction of HSCs acquired the phenotype of hepatocyte or cholangiocyte. Blocking TGF-β signaling delayed proliferation, impaired progenitor response, and scarring repair. In SB-431542 group, merely no HSCs were found coexpressed progenitor makers, such as SOX9 and AFP. Inhibition of TGF-β pathway disturbed the epithelial-mesenchymal transitions and diminished the nuclear accumulation of β-catenin as well as the expression of cytochrome P450 2E1 in HSC during liver regeneration. We identify a key role of TGF-β signaling on promoting HSC transition, which subsequently becomes progenitor for generating liver epithelial cells after PH. This process might interact with an acknowledged stem cell function signaling, Wnt/β-catenin.

Hippo signaling and epithelial cell plasticity in mammalian liver development, homeostasis, injury and disease.

A traditional view of cellular differentiation is unidirectional: progenitor cells adopt specific fates in response to environmental cues resulting in deployment of cell-specific gene expression programs and acquisition of unique differentiated cellular properties such as production of structural and functional proteins that define individual cell types. In both development and in tissue repair stem and progenitor cells are thought to both self-renew to maintain the pool of precursors and to expand to give rise to transient amplifying and differentiated cell types. Recently, however, it has become appreciated that differentiated cell types can be reprogrammed to adopt progenitor and stem cell properties. In the case of epithelial cells in the mammalian liver, hepatocytes and biliary epithelial cells there is a significant degree of plasticity between these lineages that has been implicated in mechanisms of tissue repair and in liver pathologies such as cancer. Recent studies have highlighted the role of Hippo signaling, an emerging growth control and tumor suppressor pathway, in regulating epithelial cell plasticity in the mammalian liver and in this review, the role of cellular plasticity and Hippo signaling in regulating normal and abnormal tissue responses in the mammalian liver will be discussed.

Derivatives of 1‐(2‐(Piperidin‐1‐yl)ethyl)‐1H‐benzo[d]imidazole: Synthesis, Characterization, Determining of Electronic Properties and Cytotoxicity Studies

AbstractA series of heterocyclic compounds were synthesized and fully characterized. The geometry optimization was carried out using the Density Functional Theory (DFT) method and the electronic properties of 1‐(2‐hydroxyethyl)‐3‐(2‐(piperidinium‐1‐yl)ethyl chloride)‐1H‐benzo[d]imidazol‐3‐ium bromide and 1‐(2‐methylbenzyl)‐3‐(2‐(piperidinium‐1‐yl)ethyl)‐1H‐benzo[d]imidazol‐3‐ium dichloride were calculated. Furthermore, the all compounds were evaluated for their potential anticancer activity towards different human cell lines. While 1‐(naphthalen‐1‐ylmethyl)‐3‐(2‐(piperidin‐1‐yl)ethyl)‐1H‐benzo[d]imidazol‐3‐ium chloride possessing naphthalen‐1‐ylmethyl group as substituent demonstrated important cytotoxic activity against human colorectal adenocarcinoma epithelial colon cell line (DLD‐1) with an IC50 value of 15.56 ± 4.01 μM, compound containing 4‐methylbenzyl group showed the most anticancer activity towards human liver epithelial hepatocellular carcinoma cell line (HepG2) with IC50 value of 15.16 μM. Moreover, microscopic examination of cells was done using Leica inverted microscopy and Olympus confocal microscope. Confocal images of DLD‐1 and human normal epithelial virus transformed cell line (Beas‐2B), which were treated with 20 μM of compounds, indicated that compounds 1‐(4‐methylbenzyl)‐3‐(2‐(piperidinium‐1‐yl)ethyl)‐1H‐benzo[d]imidazol‐3‐ium dichloride and 1‐(naphthalen‐1‐ylmethyl)‐3‐(2‐(piperidin‐1‐yl)ethyl)‐1H‐benzo[d]imidazol‐3‐ium chloride had more cytotoxic activity.

The Role of Autophagy in Liver Epithelial Cells and Its Impact on Systemic Homeostasis.

Autophagy plays a role in several physiological and pathological processes as it controls the turnover rate of cellular components and influences cellular homeostasis. The liver plays a central role in controlling organisms’ metabolism, regulating glucose storage, plasma proteins and bile synthesis and the removal of toxic substances. Liver functions are particularly sensitive to autophagy modulation. In this review we summarize studies investigating how autophagy influences the hepatic metabolism, focusing on fat accumulation and lipids turnover. We also describe how autophagy affects bile production and the scavenger function within the complex homeostasis of the liver. We underline the role of hepatic autophagy in counteracting the metabolic syndrome and the associated cardiovascular risk. Finally, we highlight recent reports demonstrating how the autophagy occurring within the liver may affect skeletal muscle homeostasis as well as different extrahepatic solid tumors, such as melanoma.

Quinone-thioether metabolites of hydroquinone play a dual role in promoting a vicious cycle of ROS generation: in vitro and in silico insights.

Humans are exposed to hydroquinone (HQ) via diet, smoking, occupation, and even via inhalation of polluted air. Given its preferential distribution in kidney and liver, the impact of biotransformation on the nephrotoxicity and hepatotoxicity of HQ was evaluated. Indeed, HQ and its metabolites, benzoquinone, and quinone-thioethers (50, 100, 200, and 400μM) all induced ROS-dependent cell death in both HK-2, a human kidney proximal epithelial cell line, and THLE-2, a human liver epithelial cell line, in a concentration-dependent manner. For a deeper insight into the biological mechanism of ROS stimulation, the bioinformatics database was reviewed. Intriguingly, 163 proteins were currently reported to form co-crystal complex with benzoquinone analogs, a large proportion of which are closely related to ROS generation. After a thorough assessment of the interaction affinity and binding energy, three key mitochondrial proteins that are particularly involved in electric transport, namely, cytochrome BC1, succinate dehydrogenase, and sulfide:quinone oxidoreductase, were highlighted for further verification. Their binding affinity and the action pattern were explored and validated by molecular docking and molecular dynamics simulations. Remarkably, quinone-thioether metabolites of HQ afforded high affinity to the above proteins that purportedly cause a surge in the generation of ROS. Therefore, HQ can be further converted into quinone-thioethers, which on one hand can function as substrates for redox cycling, and on the other hand may afford high affinity with key proteins evolved in mitochondrial electron transport system, leading to a vicious cycle of ROS generation. The combined data provide a prospective insight into the mechanisms of ROS motivation, expanding HQ-mediated toxicology profiles.

Intrasplenic Transplantation of Cytotoxic T-Lymphocyte Associated Protein 4-Fas Ligand--Modified Hepatic Oval Cells for Acute Liver Injury in Rats

BackgroundIntrasplenic transplantation of xenogeneic hepatic oval cells (HOCs) may provide metabolic support for acute liver injury. However, xenoreactive lymphocyte-mediated immune response hinders HOCs' survival in the xeno-spleen parenchyma. Cytotoxic T-lymphocyte associated protein 4-Fas ligand (CTLA4.FasL), a fusion product integrating 2 inhibitory elements against lymphocytes into 1 molecule, effectively inhibited the proliferation of allogeneic and autoimmune lymphocytes. The purpose of this study was to explore the effect of CTLA4.FasL on the proliferation of xenoreactive lymphocytes and evaluate the therapeutic efficacy of CTLA4.FasL-modified HOC transplantation on acute liver injury in rats. MethodsThe effect of CTLA4.FasL-modified mouse liver epithelial progenitor cells (CTLA4.FasL-LEPCs) on the proliferation of rat lymphocytes in xeno-mixed lymphocyte reaction was investigated. Furthermore, CTLA4.FasL-LEPCs were intrasplenically transplanted in carbon tetrachloride- and partial hepatectomy-treated rats, and the therapeutic effect was evaluated using hematoxylin and eosin staining and alanine aminotransferase and aspartate aminotransferase assays. The hepatocytic differentiation of CTLA4.FasL-LEPCs in xenogeneic spleen was monitored by immunohistochemical staining for albumin. ResultsIn xeno-mixed lymphocyte reaction, CTLA4.FasL-LEPCs substantially inhibited the rat lymphocytes proliferation. CTLA4.FasL-LEPC transplantation significantly ameliorated liver injury compared with mCherry-modified LEPC and LEPC transplantation, as assessed by hematoxylin and eosin staining, alanine aminotransferase, and aspartate aminotransferase assays. Albumin positive cells appeared only in CTLA4.FasL-LEPCs group, but not in the mCherry-modified LEPCs group and LEPCs group. ConclusionsOur results indicate CTLA4.FasL-LEPCs substantially improved liver function and structure in carbon tetrachloride- and partial hepatectomy-induced acute liver injury rats through long-term hepatocytic differentiation.