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We employed the suppressive subtractive hybridization to identify 41 up- and downregulated transcripts in Jurkat cells after benzo[a]pyrene (BaP) treatment. Among the 21 downregulated transcripts, we found that BaP suppresses the Keap1 transcript by 7.5-fold. Subsequent analyses revealed that BaP significantly suppresses the Keap1 message and protein levels to about 40 and 60%, respectively, of the vehicle controls in Jurkat cells without reactive oxygen species involvement. In addition, the nuclear Nrf2 (nuclear factor erythroid 2-related factor) protein content is significantly increased by 2.6-fold. The same BaP treatment to Hepa1c1c7 cells also downregulates the Keap1 message and protein levels to a similar extent. When we treated Jurkat cells with 3-(4-morpholinyl)propyl isothiocyanate, which is known to increase the amount of the Nrf2 content, we found that there is no change in the Keap1 message, but the amount of the Keap1 (kelch-like ECH-associated protein 1) protein is reduced to 75% of the vehicle controls. Although both Nrf2 target messages nqo1 and gstp1 are upregulated by BaP in Jurkat cells, only GSTP1 is upregulated at the protein level. Unlike Hepa1c1c7 cells, Jurkat cells have no detectable aryl hydrocarbon receptor and BaP metabolites, minimal CYP1A1 activity, and no quinone oxidoreductase 1 (NQO1) activity. We concluded that BaP, but not its metabolites, increases the amount of the nuclear Nrf2 protein by downregulating the Keap1 message in Jurkat cells. [ABSTRACT FROM PUBLISHER]

A previously healthy 64-year-old lady presented with hematochezia, syncope, and abdominal discomfort. Colonoscopy revealed findings consistent with segmental ischemic colitis, which resolved with supportive therapy. Herein we review the case and discuss the pathophysiology, diagnosis, and management of ischemic colitis. [ABSTRACT FROM AUTHOR]

The thioredoxin fusion protein expression system from invitrogen was modified so that 32P-labelled recombinant proteins can be easily obtained in large quantities for functional studies. Proteins that are prone to form the inclusion bodies can be functionally expressed as thioredoxin fusion proteins in Escherichia coli. After expression, the recombinant proteins can be easily phosphorylated with 32P-gamma ATP and the 32P-labelled protein can be obtained functionally via a mild proteolytic digestion to cleave off the thioredoxin moiety. A deletion construct of the Ah receptor nuclear translocator protein was used as an example to illustrate how this protein expression system works. [Copyright &y& Elsevier]

A letter to the editor is presented in response to an article related to the deficiency of odds ratio (OR) in the non-collapsibility and confounding mixing by W.K. Chan et al. in the previous issue of the journal and it also includes a response from the authors of the article.

Ubiquitin (Ub) is a post-translational modification that largely controls proteostasis through mechanisms spanning transcription, translation, and notably, protein degradation. Ub conjugation occurs through a hierarchical cascade of three enzyme classes (E1, E2, and E3s) involving >1000 proteins that regulate the ubiquitination of proteins. The E2 Ub-conjugating enzymes are the midpoint, yet their cellular roles remain under-characterized, partly due to a lack of inhibitors. For example, the cellular roles of the promiscuous E2 UBE2D/UBCH5 are not well described. Here, we develop a highly selective, multivalent, engineered protein inhibitor for the UBE2D family that simultaneously targets the RING- and backside-binding sites. In HeLa cells, these inhibitors phenocopy knockdown of UBE2D by reducing the IC 50 to cisplatin and whole-cell proteomics reveal an increased abundance of ~20% of the identified proteins, consistent with reduced Ub degradation and proteotoxic stress. These precision tools will enable new studies probing UBE2D's central role in proteome management.

Background: Human error due to risky behaviour is a common and important contributor to acute injury related to poverty. We studied whether social benefit payments mitigate or exacerbate risky behaviours that lead to emergency visits for acute injury among low-income mothers with dependent children., Methods: We analyzed total emergency department visits throughout Ontario to identify women between 15 and 55 years of age who were mothers of children younger than 18 years, who were living in the lowest socio-economic quintile and who presented with acute injury. We used universal health care databases to evaluate emergency department visits during specific days on which social benefit payments were made (child benefit distribution) relative to visits on control days over a 7-year interval (1 April 2003 to 31 March 2010)., Results: A total of 153 377 emergency department visits met the inclusion criteria. We observed fewer emergencies per day on child benefit payment days than on control days (56.4 v. 60.1, p = 0.008). The difference was primarily explained by lower values among mothers age 35 years or younger (relative reduction 7.29%, 95% confidence interval [CI] 1.69% to 12.88%), those living in urban areas (relative reduction 7.07%, 95% CI 3.05% to 11.10%) and those treated at community hospitals (relative reduction 6.83%, 95% CI 2.46% to 11.19%). No significant differences were observed for the 7 days immediately before or the 7 days immediately after the child benefit payment., Interpretation: Contrary to political commentary, we found that small reductions in relative poverty mitigated, rather than exacerbated, risky behaviours that contribute to acute injury among low-income mothers with dependent children.