Protocol to detect senescence-associated ß-galactosidase and immunoperoxidase activity in fresh-frozen murine tissues.

Double labeling to identify different markers in the same tissue section represents a useful tool either for in situ diagnosis or characterization of molecular associations. Here, we present a protocol to detect senescence-associated ß-galactosidase (SA-ßGal) and immunoperoxidase (IPO) activity in fresh-frozen murine tissues. We describe steps for tissue collection, solution preparation, SA-ßGal staining, IPO staining, hematoxylin counterstaining, microscopic observation, and signal quantification. This protocol can be used to detect in situ proteins alongside SA-ßGal activity. For complete details on the use and execution of this protocol, please refer to Pacheco-Rivera et al.1.

A model of alcoholic liver disease based on different hepatotoxics leading to liver cancer.

The worst-case scenario related to alcoholic liver disease (ALD) arises after a long period of exposure to the harmful effect of alcohol consumption along with other hepatotoxics. ALD encompasses a broad spectrum of liver-associated disorders, such as steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Based on the chronic administration of different hepatotoxics, including ethanol, sucrose, lipopolysaccharide, and low doses of diethylnitrosamine over a short period, here we aimed to develop a multiple hepatotoxic (MHT)-ALD model in the mouse that recapitulates the human ALD-associated disorders. We demonstrated that the MHT-ALD model induces ADH1A and NXN, an ethanol metabolizer and a redox-sensor enzyme, respectively; promotes steatosis associated with the induction of the lipid droplet forming FSP27, inflammation identified by the infiltration of hepatic neutrophils-positive to LY-6G marker, and the increase of MYD88 level, a protein involved in inflammatory response; and stimulates the early appearance of cellular senescence identified by the senescence markers SA-ß-gal activity and p-H2A.XSer139. It also induces fibrosis associated with increased desmin, a marker of hepatic stellate cells whose activation leads to the deposition of collagen fibers, accompanied by cell death and compensatory proliferation revealed by increased CASP3-mediated apoptosis, and KI67- and PCNA-proliferation markers, respectively. It also induces histopathological traits of malignancy and the level of the HCC marker, GSTP1. In conclusion, we provide a useful model for exploring the chronological ALD-associated alterations and stages, and addressing therapeutic approaches.

Nucleoredoxin Redox Interactions Are Sensitized by Aging and Potentiated by Chronic Alcohol Consumption in the Mouse Liver.

Aging is characterized by increased reactive species, leading to redox imbalance, oxidative damage, and senescence. The adverse effects of alcohol consumption potentiate aging-associated alterations, promoting several diseases, including liver diseases. Nucleoredoxin (NXN) is a redox-sensitive enzyme that targets reactive oxygen species and regulates key cellular processes through redox protein-protein interactions. Here, we determine the effect of chronic alcohol consumption on NXN-dependent redox interactions in the liver of aged mice. We found that chronic alcohol consumption preferentially promotes the localization of NXN either into or alongside senescent cells, declines its interacting capability, and worsens the altered interaction ratio of NXN with FLII, MYD88, CAMK2A, and PFK1 proteins induced by aging. In addition, carbonylated protein and cell proliferation increased, and the ratios of collagen I and collagen III were inverted. Thus, we demonstrate an emerging phenomenon associated with altered redox homeostasis during aging, as shown by the declining capability of NXN to interact with partner proteins, which is enhanced by chronic alcohol consumption in the mouse liver. This evidence opens an attractive window to elucidate the consequences of both aging and chronic alcohol consumption on the downstream signaling pathways regulated by NXN-dependent redox-sensitive interactions.

Erratum to: Aqueous extracts from Tenebrio molitor larval and pupal stages inhibit early hepatocarcinogenesis in vivo.

Following an Assessment by the Autonomous University of Hidalgo State and the National Institute of Genomic Medicine, this erratum corrects the authorship of this article by adding Dulce María MORENO-GARCÍA as the first author.

Is Nucleoredoxin a Master Regulator of Cellular Redox Homeostasis? Its Implication in Different Pathologies.

Nucleoredoxin (NXN), an oxidoreductase enzyme, contributes to cellular redox homeostasis by regulating different signaling pathways in a redox-dependent manner. By interacting with seven proteins so far, namely disheveled (DVL), protein phosphatase 2A (PP2A), phosphofructokinase-1 (PFK1), translocation protein SEC63 homolog (SEC63), myeloid differentiation primary response gene-88 (MYD88), flightless-I (FLII), and calcium/calmodulin-dependent protein kinase II type alpha (CAMK2A), NXN is involved in the regulation of several key cellular processes, including proliferation, organogenesis, cell cycle progression, glycolysis, innate immunity and inflammation, motility, contraction, protein transport into the endoplasmic reticulum, neuronal plasticity, among others; as a result, NXN has been implicated in different pathologies, such as cancer, alcoholic and polycystic liver disease, liver fibrogenesis, obesity, Robinow syndrome, diabetes mellitus, Alzheimer's disease, and retinitis pigmentosa. Together, this evidence places NXN as a strong candidate to be a master redox regulator of cell physiology and as the hub of different redox-sensitive signaling pathways and associated pathologies. This review summarizes and discusses the current insights on NXN-dependent redox regulation and its implication in different pathologies.

Comparative subcellular localization of NRF2 and KEAP1 during the hepatocellular carcinoma development in vivo.

The activation of Nuclear Factor, Erythroid 2 Like 2 - Kelch Like ECH Associated Protein 1 (NRF2-KEAP1) signaling pathway plays a critical dual role by either protecting or promoting the carcinogenesis process. However, its activation or nuclear translocation during hepatocellular carcinoma (HCC) progression has not been addressed yet. This study characterizes the subcellular localization of both NRF2 and KEAP1 during diethylnitrosamine-induced hepatocarcinogenesis in the rat. NRF2-KEAP1 pathway was continuously activated along with the increased expression of its target genes, namely Nqo1, Hmox1, Gclc, and Ptgr1. Similarly, the nuclear translocation of NRF2, MAF, and KEAP1 increased in HCC cells from weeks 12 to 22 during HCC progression. Likewise, colocalization of NRF2 with KEAP1 was higher in the cell nuclei of HCC neoplastic nodules than in surrounding cells. Moreover, immunofluorescence analyses revealed that the interaction of KEAP1 with filamentous Actin was disrupted in HCC cells. This disruption may be contributing to the release and nuclear translocation of NRF2 since the cortical actin cytoskeleton serves as anchoring of KEAP1. In conclusion, this evidence indicates that NRF2 is progressively activated and promotes the progression of experimental HCC.

Aqueous extracts from Tenebrio molitor larval and pupal stages inhibit early hepatocarcinogenesis in vivo.

Hepatocellular carcinoma (HCC), which is the most frequent primary liver malignancy, is ranked as the sixth most common cancer and the third leading cause of cancer-related deaths worldwide, with its incidence expected to continue rising. One of the reasons is that most patients are diagnosed at an advanced stage when therapeutic options are ineffective. The development of HCC is attributed to a chronic exposition to either one or a combination of low amounts of different hepatotoxins, such as in hepatitis virus infection, alcohol consumption, aflatoxin from contaminated foods, metabolic factors, and exposure to chemical carcinogens from tobacco smoke (Forner et al., 2018). Integrative studies combining exome sequencing, transcriptome analysis, and the genomic characterization of HCC have shown that these etiological factors may raise the frequency of particular genetic alterations, resulting in intra-tumor heterogeneity that presents a huge challenge for treatment. For example, mutations in the catenin ß-1 (CTNNB1) gene (a proto-oncogene in the WNT signaling pathway that encodes the ß|-catenin transcription factor) are strongly associated with alcohol-related HCC, whereas mutations in the telomerase reverse transcriptase (TERT) promoter and tumor protein p53 (TP53) genes are the most commonly observed in hepatitis B virus (HBV)|-associated HCC (Calderaro et al., 2017; Cancer Genome Atlas Research Network, 2017). The above findings emphasize the molecular diversity of HCC and the associations of different etiologies with distinct mechanisms in HCC progression. Consequently, prevention strategies are still attractive for HCC management.

Molecular alterations that precede the establishment of the hallmarks of cancer: An approach on the prevention of hepatocarcinogenesis.

Chronic liver injury promotes the molecular alterations that precede the establishment of cancer. Usually, several decades of chronic insults are needed to develop the most common primary liver tumor known as hepatocellular carcinoma. As other cancer types, liver cancer cells are governed by a common set of rules collectively called the hallmarks of cancer. Although those rules have provided a conceptual framework for understanding the complex pathophysiology of established tumors, therapeutic options are still ineffective in advanced stages. Thus, the molecular alterations that precede the establishment of cancer remain an attractive target for therapeutic interventions. Here, we first summarize the chemopreventive interventions targeting the early liver carcinogenesis stages. After an integrative analysis on the plethora of molecular alterations regulated by anticancer agents, we then underline and discuss that two critical processes namely oxidative stress and genetic alterations, play the role of 'dirty work laborer' in the initial cell damage and drive the transformation of preneoplastic into neoplastic cells, respectively; besides, the activation of cellular senescence works as a key mechanism in attempting to prevent the onset and establishment of liver cancer. Whereas the detrimental effects of the binomial made up of oxidative stress and genetic alterations are either eliminated or reduced, senescence activation is promoted by anticancer agents. We argue that collectively, oxidative stress, genetic alterations, and senescence are key events that influence the fate of initiated cells and the establishment of the hallmarks of cancer.

Nucleoredoxin interaction with flightless-I/actin complex is differentially altered in alcoholic liver disease.

Alcoholic liver disease (ALD) may be attributed to multiple hits driving several alterations. The aim of this work was to determine whether nucleoredoxin (NXN) interacts with flightless-I (FLII)/actin complex and how this ternary complex is altered during ALD progression induced by different ALD models. ALD was recapitulated in C57BL/6J female mice by the well-known ALD Lieber-DeCarli model, and by an in vitro human co-culture system overexpressing NXN. The effects of ethanol and low doses of lipopolysaccharides (LPS) and diethylnitrosamine (DEN) were also evaluated in vivo as a first approach of an ALD multi-hit protocol. We demonstrated that NXN interacts with FLII/actin complex. This complex was differentially altered in ALD in vivo and in vitro, and NXN overexpression partially reverted this alteration. We also showed that ethanol, LPS and DEN synergistically induced liver structural disarrangement, steatosis and inflammatory infiltration accompanied by increased levels of proliferation (Ki67), ethanol metabolism (CYP2E1), hepatocarcinogenesis (GSTP1) and LPS-inducible (MYD88 and TLR4) markers. In summary, we provide evidence showing that NXN/FLII/actin complex is involved in ALD progression and that NXN might be involved in the regulation of FLII/actin-dependent cellular functions. Moreover, we present a promising first approach of a multi-hit protocol to better recapitulate ALD pathogenesis.

Chronic administration of diethylnitrosamine to induce hepatocarcinogenesis and to evaluate its synergistic effect with other hepatotoxins in mice.

Hepatocellular carcinoma (HCC) arises after a long period of exposition to etiological factors that might be either independent or collectively contributing. Several rodent models resemble human HCC; however, the major limitation of these models is the lack of chronic injury that reproducibly mimics the molecular alterations as it occurs in humans. Thus, we hypothesized that chronic administration of different DEN treatments identifies the best-fit dose to induce the HCC and/or to determine whether small DEN doses act synergistically with other known hepatotoxins to induce HCC in mice. C57BL/6 J male mice were intraperitoneally injected twice a week for 6 weeks with different DEN doses ranging from 2.5 to 40 mg/kg body weight; then, selected doses (2.5, 5 and 20 mg/kg) for 6, 10, 14, and 18 weeks. We demonstrated that DEN at 20 mg/kg promoted reactive oxygen species and 4-hydroxynonenal production, cell proliferation inflammatory infiltrate, and fibrosis, which in turn induced liver cancer by week 18. These parameters were established by evaluating histopathological changes, HCC markers such as glutathione S-transferase placental-1 (Gstp1), Cytokeratin-19 (Ck19) and prostaglandin reductase-1 (Ptgr1); that of Cyp2e1, a DEN metabolizing enzyme; and the expression of the proliferation marker Ki67. While DEN at 2.5 and 5 mg/kg increased Gstp1 and Ck19, DEN at 20 mg/kg decreased them and Cyp2e1 expression and activity. In summary, our results demonstrate that DEN chronically administrated at 20 mg/kg induces the HCC, while DEN at 2.5 and 5 mg/kg could be useful in elucidating its synergistic effect with other hepatotoxic agents in mice.