Targeting Intercellular Adhesion Molecule-1 to Enhance Delivery of Therapeutic Enzymes for Treatment of Lysosomal Storage Diseases

Lysosomal storage diseases (LSDs) are a group of more than 40 genetically inherited diseases that result from dysfunction of specific proteins, often an enzyme, located in lysosomes within cells which leads to abnormal lysosomal accumulation of specific macromolecules. As a result, cell malfunction occurs and escalates into multi-tissue and multi-organ failures, often resulting in premature death. For several early onset LSDs, the central nervous system (CNS) is also affected and manifests fatal neuropathic and/or neurodegenerative symptoms. Within the last two decades, treatment for selective LSDs has become clinically available. Specifically, enzyme replacement therapy (ERT) by intravenous injection of recombinant enzymes holds relevant promise. Yet current ERT results in suboptimal enzyme biodistribution to many target organs, including the peripheral organs and also the CNS. Delivery to the CNS is particularly impeded due to the tight blood-brain barrier (BBB) that strictly regulates passage between the circulation system and the brain tissue. We explored the use of targeted drug delivery systems to address this issue. Specifically, we focused on targeting intercellular adhesion molecule-1 (ICAM-1), a cell surface glycoprotein that is upregulated under pathological conditions, including LSDs. In this dissertation, using in vitro, cell culture, and in vivo techniques, we examined whether ICAM-1-targeted polymer nanocarriers: (1) enhance binding, uptake, and lysosomal delivery of different enzymes in cells, (2) provide targeting and transport across endothelial and subendthelial cells of the BBB, and (3) improve accumulation of lysosomal enzymes to peripheral organs and the brain. Results suggest that after intravenous injection of enzyme coupled to ICAM-1-targeted nanocarriers, ICAM-1 targeting shift these enzymes from the circulation to tissues, enhancing enzyme accumulation over non-targeted counterparts both in peripheral organs and the brain. This could be modulated by varying parameters such as the density of targeting antibodies on the carrier coat or the carrier bulk concentration. Also, ICAM-1-targeted nanocarriers were transported across BBB models followed by uptake and lysosomal transport to neuron-like cells. ICAM-1-targeted nanocarriers preferentially bound to diseased cells and were internalized and trafficked to lysosomes, resulting in degradation of the accumulated substrate. Therefore, overall, ICAM-1-targeting shows promise in improving ERT for LSD treatment

DDE and PCB serum concentration in maternal blood and their adult female offspring

Background: Dichlorodiphenyl dichloroethylene (DDE) and polychlorinated biphenyls (PCBs) can be passed from mother to offspring through placental transfer or breast feeding. Unknown is whether maternal levels can predict concentrations in adult offspring. Objectives: To test the association between maternal blood levels of DDE and PCBs and adult female offspring levels of these compounds using data from the Michigan Fisheaters’Cohort. Methods: DDE and PCB concentrations were determined in 132 adult daughters from 84 mothers. Prenatal exposures were estimated based on maternal DDE and PCB serum levels measured between 1973 and 1991. Levels in adult daughters were regressed on maternal and estimated prenatal exposure levels, adjusting for potential confounders using linear mixed models. Confounders included daughter’s age, birth order, birth weight, number of pregnancies, the length of time the daughter was breast-fed, the length of time the daughter breast-fed her own children, last year fish-eating status, body mass index, and lipid weight. Results: The median age of the participants was 40.4 years (range 18.4 to 65.4, 5–95 percentiles 22.5-54.6%, respectively). Controlling for confounders and intra-familial associations, DDE and PCB concentrations in adult daughters were significantly positively associated with estimated prenatal levels and with maternal concentrations. The proportion of variance in the adult daughters’ organochlorine concentrations explained by the maternal exposure levels is approximately 23% for DDE and 43% for PCBs. The equivalent of a median of 3.67 μg/L prenatal DDE and a median of 2.56 μg/L PCBs were 15.64 and 10.49 years of fish consumption, respectively. When controlling for effects of the shared environment (e.g., fish diet) by using a subsample of paternal levels measured during the same time frames (n=53 and n=37), we determined that the direct maternal transfer remains important. Conclusions: Estimated intrauterine DDE and PCB levels predicted concentrations in adult female offspring 40 years later. Interpretation of adverse health effects from intrauterine exposures of persistent pollutants may need to consider the sustained impact of maternal DDE and PCB levels found in their offspring

NO signaling and S-nitrosylation regulate PTEN inhibition in neurodegeneration

<p>Abstract</p> <p>Background</p> <p>The phosphatase PTEN governs the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway which is arguably the most important pro-survival pathway in neurons. Recently, PTEN has also been implicated in multiple important CNS functions such as neuronal differentiation, plasticity, injury and drug addiction. It has been reported that loss of PTEN protein, accompanied by Akt activation, occurs under excitotoxic conditions (stroke) as well as in Alzheimer's (AD) brains. However the molecular signals and mechanism underlying PTEN loss are unknown.</p> <p>Results</p> <p>In this study, we investigated redox regulation of PTEN, namely S-nitrosylation, a covalent modification of cysteine residues by nitric oxide (NO), and H₂O₂-mediated oxidation. We found that S-nitrosylation of PTEN was markedly elevated in brains in the early stages of AD (MCI). Surprisingly, there was no increase in the H₂O₂-mediated oxidation of PTEN, a modification common in cancer cell types, in the MCI/AD brains as compared to normal aged control. Using several cultured neuronal models, we further demonstrate that S-nitrosylation, in conjunction with NO-mediated enhanced ubiquitination, regulates both the lipid phosphatase activity and protein stability of PTEN. S-nitrosylation and oxidation occur on overlapping and distinct Cys residues of PTEN. The NO signal induces PTEN protein degradation via the ubiquitin-proteasome system (UPS) through NEDD4-1-mediated ubiquitination.</p> <p>Conclusion</p> <p>This study demonstrates for the first time that NO-mediated redox regulation is the mechanism of PTEN protein degradation, which is distinguished from the H₂O₂-mediated PTEN oxidation, known to only inactivate the enzyme. This novel regulatory mechanism likely accounts for the PTEN loss observed in neurodegeneration such as in AD, in which NO plays a critical pathophysiological role.</p

On the Efficacy and Mediation of a One-on-One HIV Risk-Reduction Intervention for African American Men Who Have Sex With Men: A Randomized Controlled Trial

We examined the efficacy and mediation of Being Responsible for Ourselves (BRO), an HIV/STI risk reduction intervention for African American men who have sex with men (MSM), the population with the highest HIV diagnosis rate in the US. We randomized African American MSM to one of two interventions: BRO HIV/STI risk reduction, targeting condom use; or attention-matched control, targeting physical activity and healthy diet. The interventions were based on social cognitive theory, the reasoned-action approach, and qualitative research. Men reporting anal intercourse with other men in the past 90 days were eligible and completed pre-intervention

Perspectives on Finances and Mental Health Status among Low-Income Los Angeles Latinas

Abstract Research has established a link between financial challenges and mental health outcomes. Understanding this linkage among low-income Latinas who face unique experiences and challenges in relation to managing their household finances is important. This study utilized a community-based participatory qualitative research method to explore perspectives on financial and mental health among Latinas residing in Los Angeles County. The implications of this study are applicable when conducting a culturally responsive financial therapy program. Three focus groups were conducted with mainly immigrant, Spanish-speaking, low-income Latinas (n = 37). The study found that though participants face financial stressors tied to managing finances, they were eager to learn new skills and tools for improved financial practices and mental health therapies. For financial education interventions targeted to Latinas, it is best to use interventions that incorporate peer-support groups, improve knowledge about financial management tools and financial products available in the community, and therapeutic interventions to address financial stress. Key words: immigrants, household financial decision-making, savings, formal financial services, financial stres

Tissue-specific variation in DNA methylation levels along human chromosome 1

<p>Abstract</p> <p>Background</p> <p>DNA methylation is a major epigenetic modification important for regulating gene expression and suppressing spurious transcription. Most methods to scan the genome in different tissues for differentially methylated sites have focused on the methylation of CpGs in CpG islands, which are concentrations of CpGs often associated with gene promoters.</p> <p>Results</p> <p>Here, we use a methylation profiling strategy that is predominantly responsive to methylation differences outside of CpG islands. The method compares the yield from two samples of size-selected fragments generated by a methylation-sensitive restriction enzyme. We then profile nine different normal tissues from two human donors relative to spleen using a custom array of genomic clones covering the euchromatic portion of human chromosome 1 and representing 8% of the human genome. We observe gross regional differences in methylation states across chromosome 1 between tissues from the same individual, with the most striking differences detected in the comparison of cerebellum and spleen. Profiles of the same tissue from different donors are strikingly similar, as are the profiles of different lobes of the brain. Comparing our results with published gene expression levels, we find that clones exhibiting extreme ratios reflecting low relative methylation are statistically enriched for genes with high expression ratios, and <it>vice versa</it>, in most pairs of tissues examined.</p> <p>Conclusion</p> <p>The varied patterns of methylation differences detected between tissues by our methylation profiling method reinforce the potential functional significance of regional differences in methylation levels outside of CpG islands.</p

Selenium supplementation and insulin resistance in a randomized, clinical trial

Objective: While controversial, observational and randomized clinical trial data implicate the micronutrient selenium (Se) in the development of type 2 diabetes (T2D). The aim of this study was to test the hypothesis that Se supplementation adversely affects pancreatic beta-cell function and insulin sensitivity. Research design and methods: In a subset of 400 individuals participating in a randomized, placebocontrolled trial of Se at 200 mu g/day for colorectal adenomatous polyps, fasting plasma glucose and insulin were measured before randomization and within 6 months of completing intervention. Change in the homeostasis model assessment-beta cell function (HOMA2-%beta) and insulin sensitivity (HOMA2-%S) were compared between arms. A subgroup of 175 (79 Se and 96 placebo) participants underwent a modified oral glucose tolerance test (mOGTT) at the end of intervention and change in glucose values was assessed. Results: No statistically significant differences were observed for changes in HOMA2-%beta or HOMA2-%S between those who received Se compared with placebo. After a mean of 2.9 years on study, mean HOMA2-%beta values were 3.1 +/- 24.0 and 3.1 +/- 29.8 for the Se and placebo groups, respectively (p=0.99). For HOMA2-%S, the values were -0.5 +/- 223.2 and 80.9 +/- 1530.9 for the Se and placebo groups, respectively (p=1.00). Stratification by sex or age did not reveal any statistically significant effects on insulin sensitivity by treatment group. For mOGTT, mean baseline fasting blood glucose concentrations were significantly higher among participants in the placebo group compared with the Se group (96.6 +/- 14.6 and 92.3 +/- 12.0, respectively; p=0.04), a trend which remained through the 20 min assessment. Conclusions: These findings do not support a significant adverse effect of daily Se supplementation with 200 mu g/day of selenized yeast on beta-cell function or insulin sensitivity as an explanation for previously reported associations between Se and T2D. Further clarification of longer term effects of Se is needed.National Cancer Institute Cancer Center Support Grant [P30 CA023074]; NIH/NCI [R01CA151708, P01 CA041108]; NIH [R01DK047396]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]