Physiological Basis of No-go Decay with Sod1Δ Saccharomyces cerevisiae

Chromium VI (Cr (VI)), a common byproduct of industry, induces oxidative stress in cells, resulting in altered gene expression, increased apoptosis, and cell death. Previous work has shown showed that Cr (VI) exposure results in the formation of 8-oxoguanines (8- oxo(G) bases) in mRNA. These 8-oxo(G) bases lead to ribosome stalls during translation and the activation of no-go decay. Upon ribosome stalls, no-go decay is activated. During no-go decay, the Dom34p/Hbsp1p complex acts to remove stalled ribosomes and promote endonucleolytic cleavage of the damaged mRNA at the stall site. Although oxidative agents and other non-physiological substrates have been used to activate no-go decay, very little work exists to elucidate the true physiological role of this pathway. Sod1p (superoxide dismutase 1) scavenges free oxygen species by catalyzing the partitioning of superoxide (O2- ) into O2 and H2O2. Cells that lack functional Sod1p have been observed to have increased oxidative stress resulting in increased P-body assembly, while leading only to an attenuation of global translation. To determine whether no-go decay is being activated in strains lacking Sod1p, double mutant strains were created in which SOD1 was knocked out in conjunction with one of the effectors of no-go decay. Consistent with no-go decay being activated in response to oxidation, the hbs1Δsod1Δ strain resulted in a decrease in Pbody assembly, as compared to wild-type strain, even in the presence of Cr (VI). To assess how effective Sod1p is as a deterrent to 8-oxo(G) base formation in the presence of Cr (VI), the SOD1 gene was overexpressed in yeast cells. The presence of high levels of Sod1p was hypothesized to limit the number of 8-oxo(G) in response to the Cr (VI) and affect P-body assembly. However, overexpression of Sod1p does not seem to compensate for Cr (VI) mediated oxidation. Instead, we will look under milder oxidative conditions. Interestingly, Stm1p is thought to potentially to aid in the dissociation and recycling of the ribosomal subunits. In the stm1Δ and wild-type strain, P-body assembly was mildly decreased when treated with 17 Cr (VI), which is consistent with Stm1p functioning to recycle ribosomes downstream of no-go decay. Additionally, stm1Δ can suppress sod1Δ growth defects on Cr (VI) containing media.https://openriver.winona.edu/urc2019/1068/thumbnail.jp

Protective Role for Properdin in Progression of Experimental Murine Atherosclerosis

Genetic, dietary and immune factors contribute to the pathogenesis of atherosclerosis in humans and mice. Complement activation is an integral part of the innate immune defence but also shapes cellular responses and influences directly triglyceride synthesis. Deficiency of Factor B of the alternative pathway (AP) of complement is beneficial in LDLR−/− mice fed a high fat diet. The serum glycoprotein properdin is a key positive regulator of the AP but has not been studied in experimental atherosclerosis. Atherosclerosis was assessed after feeding low fat (LFD) or high fat (HFD) Western type diets to newly generated LDLR−/− ProperdinKO (LDLR−/−PKO) and LDLR−/−PWT mice. Lipids, lymphocytes and monocytes were similar among genotypes, genders and diets. Complement C3, but not C3adesarg, levels were enhanced in LDLR−/−PKO mice regardless of diet type or gender. Non-esterified fatty acids (NEFA) were decreased in male LDLR−/−PKO fed a HFD compared with controls. All mice showed significant atherosclerotic burden in aortae and at aortic roots but male LDLR−/− mice fed a LFD were affected to the greatest extent by the absence of properdin. The protective effect of properdin expression was overwhelmed in both genders of LDLR−/−mice when fed a HFD. We conclude that properdin plays an unexpectedly beneficial role in the development and progression of early atherosclerotic lesions

Association of adipocyte genes with ASP expression: a microarray analysis of subcutaneous and omental adipose tissue in morbidly obese subjects

<p>Abstract</p> <p>Background</p> <p>Prevalence of obesity is increasing to pandemic proportions. However, obese subjects differ in insulin resistance, adipokine production and co-morbidities. Based on fasting plasma analysis, obese subjects were grouped as Low Acylation Stimulating protein (ASP) and Triglyceride (TG) (LAT) vs High ASP and TG (HAT). Subcutaneous (SC) and omental (OM) adipose tissues (n = 21) were analysed by microarray, and biologic pathways in lipid metabolism and inflammation were specifically examined.</p> <p>Methods</p> <p>LAT and HAT groups were matched in age, obesity, insulin, and glucose, and had similar expression of insulin-related genes (InsR, IRS-1). ASP related genes tended to be increased in the HAT group and were correlated (factor B, adipsin, complement C3, p < 0.01 each). Differences between LAT and HAT group were almost exclusively in SC tissue, with little difference in OM tissue. Increased C5L2 (p < 0.01), an ASP receptor, in HAT suggests a compensatory ASP pathway, associated with increased TG storage.</p> <p>Results</p> <p>HAT adipose tissue demonstrated increased lipid related genes for storage (CD36, DGAT1, DGAT2, SCD1, FASN, and LPL), lipolysis (HSL, CES1, perilipin), fatty acid binding proteins (FABP1, FABP3) and adipocyte differentiation markers (CEBPα, CEBPβ, PPARγ). By contrast, oxidation related genes were decreased (AMPK, UCP1, CPT1, FABP7). HAT subjects had increased anti-inflammatory genes TGFB1, TIMP1, TIMP3, and TIMP4 while proinflammatory PIG7 and MMP2 were also significantly increased; all genes, p < 0.025.</p> <p>Conclusion</p> <p>Taken together, the profile of C5L2 receptor, ASP gene expression and metabolic factors in adipose tissue from morbidly obese HAT subjects suggests a compensatory response associated with the increased plasma ASP and TG.</p

Racial difference in Acylation Stimulating Protein (ASP) correlates to triglyceride in non-obese and obese African American and Caucasian women

© 2009 Scantlebury-Manning et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Increasing Rates of Obesity among HIV-Infected Persons during the HIV Epidemic

The prevalence and factors associated with overweight/obesity among human immunodeficiency virus (HIV)-infected persons are unknown.We evaluated prospective data from a U.S. Military HIV Natural History Study (1985-2004) consisting of early diagnosed patients. Statistics included multivariate linear regression and longitudinal linear mixed effects models.Of 1682 patients, 2% were underweight, 37% were overweight, and 9% were obese at HIV diagnosis. Multivariate predictors of a higher body mass index (BMI) at diagnosis included more recent year of HIV diagnosis, older age, African American race, and earlier HIV stage (all p<0.05). The majority of patients (62%) gained weight during HIV infection. Multivariate factors associated with a greater increase in BMI during HIV infection included more recent year of diagnosis, lower BMI at diagnosis, higher CD4 count, lower HIV RNA level, lack of AIDS diagnosis, and longer HIV duration (all p<0.05). Nucleoside agents were associated with less weight gain; other drug classes had no significant impact on weight change in the HAART era.HIV-infected patients are increasingly overweight/obese at diagnosis and during HIV infection. Weight gain appears to reflect improved health status and mirror trends in the general population. Weight management programs may be important components of HIV care

The Effect of Human Immunodeficiency Virus on Hepatitis B Virus Serologic Status in Co-Infected Adults

Factors associated with serologic hepatitis B virus (HBV) outcomes in HIV-infected individuals remain incompletely understood, yet such knowledge may lead to improvements in the prevention and treatment of chronic HBV infection.HBV-HIV co-infected cohort participants were retrospectively analyzed. HBV serologic outcomes were classified as chronic, resolved, and isolated-HBcAb. Chronic HBV (CHBV) was defined as the presence of HBsAg on two or more occasions at least six months apart. Risk factors for HBV serologic outcome were assessed using logistic regression. Of 2037 participants with HBV infection, 281 (14%) had CHBV. Overall the proportions of HBV infections classified as CHBV were 11%, 16%, and 19% for CD4 cell count strata of > or =500, 200-499, and <200, respectively (p<0.0001). Risk of CHBV was increased for those with HBV infection occurring after HIV diagnosis (OR 2.62; 95% CI 1.78-3.85). This included the subset with CD4 count > or =500 cells/microL where 21% of those with HBV after HIV diagnosis had CHBV compared with 9% for all other cases of HBV infection in this stratum (p = 0.0004). Prior receipt of HAART was associated with improved HBV serologic outcome overall (p = 0.012), and specifically among those with HBV after HIV (p = 0.002). In those with HBV after HIV, HAART was associated with reduced risk of CHBV overall (OR 0.18; 95% CI 0.04-0.79); including reduced risk in the subsets with CD4 > or =350 cells/microL (p<0.001) and CD4 > or =500 cells/microL (p = 0.01) where no cases of CHBV were seen in those with a recent history of HAART use.Clinical indicators of immunologic status in HIV-infected individuals, such as CD4 cell count, are associated with HBV serologic outcome. These data suggest that immunologic preservation through the increased use of HAART to improve functional anti-HBV immunity, whether by improved access to care or earlier initiation of therapy, would likely improve HBV infection outcomes in HIV-infected individuals