Walter Klimecki

Nonalcoholic fatty liver disease (NAFLD) may progress from simple steatosis to severe, nonalcoholic steatohepatitis (NASH) in 7-14% of the U.S. population through a 2(nd) 'hit' in the form of increased oxidative stress and inflammation. ER stress signaling and the unfolded protein response (UPR) are triggered when high levels of lipids and misfolded proteins alter ER homeostasis creating a lipotoxic environment within NAFLD livers. The objective of this study was to determine the coordinate regulation of ER stress-associated genes in the progressive stages of human NAFLD. Human liver samples categorized as normal, steatosis, NASH (Fatty) and NASH (Not Fatty) were analyzed by individual Affymetrix GeneChip Human 1.0ST microarrays, immunoblots, and immunohistochemistry. A gene set enrichment analysis was performed on autophagy, apoptosis, lipogenesis and ER stress/UPR gene categories. An enrichment of downregulated genes in the ER stress associated-lipogenesis and ER stress/UPR gene categories was observed in NASH. Conversely, an enrichment of upregulated ER stress-associated genes for autophagy and apoptosis gene categories was observed in NASH. Protein expression of the adaptive liver response protein STC2 and the transcription factor XBP-1s were significantly elevated among NASH samples while other downstream ER stress proteins including CHOP, ATF4 and phosphorylated JNK and eIF2α were not significantly changed in disease progression. Increased nuclear accumulation of total XBP-1 protein was observed in steatosis and NASH livers. The findings reveal the presence of a coordinated, adaptive transcriptional response to hepatic ER stress in human NAFLD.

Using an integrated approach of epigenomic scanning and gene expression profiling, we found aberrant methylation and epigenetic silencing of a small neighborhood of contiguous genes-the HOXA gene cluster in human breast cancer. The observed transcriptional repression was localized to approximately 100 kb of the HOXA gene cluster and did not extend to genes located upstream or downstream of the cluster. Bisulfite sequencing, chromatin immunoprecipitation, and quantitative reverse transcription-PCR analysis confirmed that the loss of expression of the HOXA gene cluster in human breast cancer is closely linked to aberrant DNA methylation and loss of permissive histone modifications in the region. Pharmacologic manipulations showed the importance of these aberrant epigenetic changes in gene silencing and support the hypothesis that aberrant DNA methylation is dominant to histone hypoacetylation. Overall, these data suggest that inactivation of the HOXA gene cluster in breast cancer may represent a new type of genomic lesion-epigenetic microdeletion. We predict that epigenetic microdeletions are common in human cancer and that they functionally resemble genetic microdeletions but are defined by epigenetic inactivation and transcriptional silencing of a relatively small set of contiguous genes along a chromosome, and that this type of genomic lesion is metastable and reversible in a classic epigenetic fashion.

Environ Res. 2016 Apr;146:331-9. doi: 10.1016/j.envres.2015.12.011. Epub 2016 Jan 21.Multimedia exposures to arsenic and lead for children near an inactive mine tailings and smelter site.Loh MM1, Sugeng A2, Lothrop N2, Klimecki W3, Cox M4, Wilkinson ST5, Lu Z6, Beamer PI2.Author information1Department of Community, Environment and Policy, Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N. Martin Avenue, P.O. Box 245163, Tucson, AZ 85718, USA. Electronic address: mloh@email.arizona.edu.2Department of Community, Environment and Policy, Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N. Martin Avenue, P.O. Box 245163, Tucson, AZ 85718, USA.3Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, P.O. Box 210207, Tucson, AZ 85724, USA.4Hospital Medicine and Outreach, Department of Pediatrics, Diamond Children's Medical Center, The University of Arizona, 1501 N. Campbell Ave. Tucson, AZ 85724, USA.5Superfund Research Program, The University of Arizona, 1110 E. South Campus Dr., Tucson, AZ 85721, USA.6BIO5 Institute, The University of Arizona, 1657 E. Mabel St., Tucson, AZ 85721, USA.AbstractChildren living near contaminated mining waste areas may have high exposures to metals from the environment. This study investigates whether exposure to arsenic and lead is higher in children in a community near a legacy mine and smelter site in Arizona compared to children in other parts of the United States and the relationship of that exposure to the site. Arsenic and lead were measured in residential soil, house dust, tap water, urine, and toenail samples from 70 children in 34 households up to 7 miles from the site. Soil and house dust were sieved, digested, and analyzed via ICP-MS. Tap water and urine were analyzed without digestion, while toenails were washed, digested and analyzed. Blood lead was analyzed by an independent, certified laboratory. Spearman correlation coefficients were calculated between each environmental media and urine and toenails for arsenic and lead. Geometric mean arsenic (standard deviation) concentrations for each matrix were: 22.1 (2.59) ppm and 12.4 (2.27)ppm for soil and house dust (63μm), 5.71 (6.55)ppb for tap water, 14.0 (2.01)μg/L for specific gravity-corrected total urinary arsenic, 0.543 (3.22)ppm for toenails. Soil and vacuumed dust lead concentrations were 16.9 (2.03)ppm and 21.6 (1.90) ppm. The majority of blood lead levels were below the limit of quantification. Arsenic and lead concentrations in soil and house dust decreased with distance from the site. Concentrations in soil, house dust, tap water, along with floor dust loading were significantly associated with toenail and urinary arsenic but not lead. Mixed models showed that soil and tap water best predicted urinary arsenic. In our study, despite being present in mine tailings at similar levels, internal lead exposure was not high, but arsenic exposure was of concern, particularly from soil and tap water. Naturally occurring sources may be an additional important contributor to exposures in certain legacy mining areas.

PMID: 23648393;PMCID: PMC3714307;Abstract:

Understanding how arsenic exacts its diverse, global disease burden is hampered by a limited understanding of the particular biological pathways that are disrupted by arsenic and underlie pathogenesis. A reductionist view would predict that a small number of basic pathways are generally perturbed by arsenic, and manifest as diverse diseases. Following an initial observation that arsenite-exposed cells in culture acidify their media more rapidly than control cells, the report here shows that low level exposure to arsenite (75. ppb) is sufficient to induce aerobic glycolysis (the Warburg effect) as a generalized phenomenon in cultured human primary cells and cell lines. Expanded studies in one such cell line, the non-malignant pulmonary epithelial line, BEAS-2B, established that the arsenite-induced Warburg effect was associated with increased accumulation of intracellular and extracellular lactate, an increased rate of extracellular acidification, and inhibition by the non-metabolized glucose analog, 2-deoxy-D-glucose. Associated with the induction of aerobic glycolysis was a pathway-wide induction of glycolysis gene expression, as well as protein accumulation of an established glycolysis master-regulator, hypoxia-inducible factor 1A. Arsenite-induced alteration of energy production in human cells represents the type of fundamental perturbation that could extend to many tissue targets and diseases. © 2013 Elsevier Inc.