Hepatocyte-specific mitogen-activated protein kinase phosphatase 1 in sexual dimorphism and susceptibility to alcohol induced liver injury.

Background: It is well established that females are more susceptible to the toxic effects of alcohol, although the exact mechanisms are still poorly understood. Previous studies noted that alcohol reduces the expression of mitogen-activated protein kinase phosphatase 1 (MKP1), a negative regulator of mitogen-activated protein kinases (MAPK) in the liver. However, the role of hepatocyte- specific MKP1 in the pathogenesis of alcohol-associated liver disease (ALD) remains uncharacterized.

Dysregulated Cyclic Nucleotide Metabolism in Alcohol-Associated Steatohepatitis: Implications for Novel Targeted Therapies.

Background: Cyclic nucleotides are second messengers, which play significant roles in numerous biological processes. Previous work has shown that cAMP and cGMP signaling regulates various pathways in liver cells, including Kupffer cells, hepatocytes, hepatic stellate cells, and cellular components of hepatic sinusoids. Importantly, it has been shown that cAMP levels and enzymes involved in cAMP homeostasis are affected by alcohol.

Natural γδT17 cell development and functional acquisition is governed by the mTORC2--Maf-controlled mitochondrial fission pathway.

Natural IL-17-producing γδ T cells (γδT17 cells) are unconventional innate-like T cells that undergo functional programming in the fetal thymus. However, the intrinsic metabolic mechanisms of γδT17 cell development remain undefined. Here, we demonstrate that mTORC2, not mTORC1, selectively controls the functional fate commitment of γδT17 cells through regulating transcription factor c-Maf expression.

Irreversible electroporation augments β-glucan induced trained innate immunity for the treatment of pancreatic ductal adenocarcinoma.

Background: Pancreatic cancer (PC) is a challenging diagnosis that is yet to benefit from the advancements in immuno-oncologic treatments. Irreversible electroporation (IRE), a non-thermal method of tumor ablation, is used in treatment of select patients with locally-advanced unresectable PC and has potentiated the effect of certain immunotherapies. Yeast-derived particulate β-glucan induces trained innate immunity and successfully reduces murine PC tumor burden.

Tumor-derived exosomes drive immunosuppressive macrophages in a pre-metastatic niche through glycolytic dominant metabolic reprogramming.

One of the defining characteristics of a pre-metastatic niche, a fundamental requirement for primary tumor metastasis, is infiltration of immunosuppressive macrophages. How these macrophages acquire their phenotype remains largely unexplored. Here, we demonstrate that tumor-derived exosomes (TDEs) polarize macrophages toward an immunosuppressive phenotype characterized by increased PD-L1 expression through NF-kB-dependent, glycolytic-dominant metabolic reprogramming.

ZEB1 Regulates Multiple Oncogenic Components Involved in Uveal Melanoma Progression.

Human uveal melanoma (UM) is a major ocular malignant tumor with high risk of metastasis and requires multiple oncogenic factors for progression. ZEB1 is a zinc finger E-box binding transcription factor known for participating epithelial-mesenchymal transition (EMT), a critical cellular event for metastasis of malignant tumors of epithelium origin. ZEB1 is also expressed in UM and high expression of ZEB1 correlates with UM advancement, but has little effect on cell morphology.

LINE-1 silencing by retinoblastoma proteins is effected through the nucleosomal and remodeling deacetylase multiprotein complex.

Background: Long Interspersed Nuclear Element-1 (L1) is an oncogenic mammalian retroelement silenced early in development via tightly controlled epigenetic mechanisms. We have previously shown that the regulatory region of human and murine L1s interact with retinoblastoma (RB) proteins to effect retroelement silencing. The present studies were conducted to identify the corepressor complex responsible for RB-mediated silencing of L1.

Albumin-like proteins are critical regulators of vascular redox signaling.

This laboratory previously identified an albumin-like protein (denoted as p70) as a component of the macromolecular complex assembled within the 5'-regulatory region of redox-sensitive genes in vascular smooth muscle cells (vSMCs). Here we show that p70 is present in the cytosolic and nuclear compartments of vSMCs and dynamically responsive to redox status. Intense cytoplasmic and perinuclear staining, coupled with enhanced nuclear localization, was observed in vSMCs, but not HepG2 cells, treated with benzo(a)pyrene (BaP), H(2)O(2), or N-acetylcysteine, agents known to modulate redox status.

HPV E7 viral oncoprotein disrupts transcriptional regulation of L1Md retrotransposon.

Murine L1Md-A5 retrotransposon is a redox-inducible element regulated by Nrf-2/JunD and E2F/Rb-binding sites within its promoter (5'-UTR). Because the human papillomavirus (HPV) oncoprotein E7 interacts with retinoblastoma (pRb) and members of the AP1 family, studies were conducted to examine functional interactions between HPV E7, pRb, and histone deacetylase 2 (HDAC2) in the regulation of L1Md-A5. Using a transient heterologous transcription system we found that HPV E7 alone, or in combination with HDAC2, disrupted pRb-mediated L1MdA-5 transactivation.

Retinoblastoma family of proteins and chromatin epigenetics: a repetitive story in a few LINEs.

The retinoblastoma (RB) protein family in mammals is composed of three members: pRB (or RB1), p107, and p130. Although these proteins do not directly bind DNA, they associate with the E2F family of transcription factors which function as DNA sequence-specific transcription factors. RB proteins alter gene transcription via direct interference with E2F functions, as well as recruitment of transcriptional repressors and corepressors that silence gene expression through DNA and histone modifications.

Epigenetic control of embryonic renal cell differentiation by L1 retrotransposon.

Background: L1 retroelements may play a central role in morphogenesis through epigenetic mechanisms involving recruitment of chromatin modifying protein complexes. Retroelements are repressed in terminally differentiated cells, and highly active in embryonic, undifferentiated, and transformed cells. It is not clear if the modulation of differentiation by L1 is a "cause" or "effect".

Reactivation of L1 retrotransposon by benzo(a)pyrene involves complex genetic and epigenetic regulation.

Benzo(a)pyrene (BaP), is an environmental pollutant present in tobacco smoke and a byproduct of fossil fuel combustion which likely contributes to the tumorigenic processes in human cancers including lung and esophageal. Long Interspersed Nuclear Element-1 (LINE-1) or L1 is a mobile element within the mammalian genome that propagates via a "copy-and-paste" mechanism using reverse transcriptase and RNA intermediates. L1 is strongly expressed during early embryogenesis and then silenced as cells initiate differentiation programming.

Assessment of genetic variation for the LINE-1 retrotransposon from next generation sequence data.

Background: In humans, copies of the Long Interspersed Nuclear Element 1 (LINE-1) retrotransposon comprise 21% of the reference genome, and have been shown to modulate expression and produce novel splice isoforms of transcripts from genes that span or neighbor the LINE-1 insertion site.

Results: In this work, newly released pilot data from the 1000 Genomes Project is analyzed to detect previously unreported full length insertions of the retrotransposon LINE-1. By direct analysis of the sequence data, we have identified 22 previously unreported LINE-1 insertion sites within the sequence data reported for a mother/father/daughter trio.

Epigenetic control of mammalian LINE-1 retrotransposon by retinoblastoma proteins.

Long interspersed nuclear elements (LINEs or L1 elements) are targeted for epigenetic silencing during early embryonic development and remain inactive in most cells and tissues. Here we show that E2F-Rb family complexes participate in L1 elements epigenetic regulation via nucleosomal histone modifications and recruitment of histone deacetylases (HDACs) HDAC1 and HDAC2. Our experiments demonstrated that (i) Rb and E2F interact with human and mouse L1 elements, (ii) L1 elements are deficient in both heterochromatin-associated histone marks H3 tri methyl K9 and H4 tri methyl K20 in Rb family triple knock out (Rb, p107, and p130) fibroblasts (TKO), (iii) L1 promoter exhibits increased histone H3 acetylation in the absence of HDAC1 and HDAC2 recruitment, (iv) L1 expression in TKO fibroblasts is upregulated compared to wild type counterparts, (v) L1 expression increases in the presence of the HDAC inhibitor TSA.

Ajuba functions as a histone deacetylase-dependent co-repressor for autoregulation of the growth factor-independent-1 transcription factor.

Growth factor independent-1 (Gfi1) is a zinc finger protein with a SNAG-transcriptional repressor domain. Ajuba is a LIM domain protein that shuttles between the cytoplasm and the nucleus. Ajuba functions as a co-repressor for synthetic Gfi1 SNAG-repressor domain-containing constructs, but a role for Ajuba co-repression of the cognate DNA bound Gfi1 protein has not been defined.

Activation profiles of HSPA5 during the glomerular mesangial cell stress response to chemical injury.

Environmental injury has been associated with endoplasmic reticulum (ER) stress, a response characterized by activation of the unfolded protein response, proteasomal degradation of proteins, and induction of HSPA5, also known as GRP78 or BiP. Although HSPA5 has been implicated in the stress response to environmental injury in several cell types, its role in the glomerular ER stress response is unknown. In this study, we evaluated HSPA5 activation profiles in rat glomerular mesangial cells (rGMCs) challenged with heavy metals (HgCl2 or Pb2+ acetate) or polycyclic aromatic hydrocarbons (PAHs, ie, benzo(a)pyrene [BaP]).

The zinc finger transcription factor ZFHX1A is linked to cell proliferation by Rb-E2F1.

ZFHX1A is expressed in proliferating cells in the developing embryo, and in the present study we provide evidence that its expression is confined to proliferating cells through dependence on the Rb (retinoblastoma protein) family/E2F cell cycle pathway. Mutation of the Rb or E2F1 genes lead to induction of ZFHX1A mRNA, implying that the Rb-E2F1 repressor complex is important for repression of ZFHX1A. This repression is associated with recruitment of an E2F-Rb-histone deacetylase repressor complex to the promoter.

Computational and biological inference of gene regulatory networks of the LINE-1 retrotransposon.

Computational approaches were used to define structural and functional determinants of a putative genetic regulatory network of murine LINE-1 (long interspersed nuclear element-1), an active mammalian retrotransposon that uses RNA intermediates to populate new sites throughout the genome. Polymerase (RNA) II polypeptide E AI845735 and mouse DNA homologous to Drosophila per fragment M12039 were identified as primary attractors. siRNA knockdown of the aryl hydrocarbon receptor NM_013464 modulated gene expression within the network, including LINE-1, Sgpl1, Sdcbp, and Mgst1.

Hsp27 regulates Akt activation and polymorphonuclear leukocyte apoptosis by scaffolding MK2 to Akt signal complex.

We have shown previously that Akt exists in a signal complex with p38 MAPK, MAPK-activated protein kinase-2 (MK2), and heat shock protein 27 (Hsp27) and MK2 phosphorylates Akt on Ser-473. Additionally, dissociation of Hsp27 from Akt, prior to Akt activation, induced polymorphonuclear leukocyte (PMN) apoptosis. However, the role of Hsp27 in regulating Akt activation was not examined.

Gfi1 coordinates epigenetic repression of p21Cip/WAF1 by recruitment of histone lysine methyltransferase G9a and histone deacetylase 1.

The growth factor independent 1 (Gfi1) transcriptional regulator oncoprotein plays a crucial role in hematopoietic, inner ear, and pulmonary neuroendocrine cell development and governs cell processes as diverse as self-renewal of hematopoietic stem cells, proliferation, apoptosis, differentiation, cell fate specification, and oncogenesis. However, the molecular basis of its transcriptional functions has remained elusive. Here we show that Gfi1 recruits the histone lysine methyltransferase G9a and the histone deacetylase 1 (HDAC1) in order to modify the chromatin of genes targeted for repression by Gfi1.

Suppression of IL7Ralpha transcription by IL-7 and other prosurvival cytokines: a novel mechanism for maximizing IL-7-dependent T cell survival.

Survival of naive T cells is dependent upon IL-7, which is present in vivo in limiting amounts with the result that naive T cells must compete for IL-7-mediated survival signals. It would seem imperative during T cell homeostasis that limiting IL-7 be shared by the greatest possible number of T cells. We now describe a novel regulatory mechanism that specifically suppresses IL7Ralpha transcription in response to IL-7 and other prosurvival cytokines (IL-2, IL-4, IL-6, and IL-15).