Effects of Altering HSPG Binding and Capsid Hydrophilicity on Retinal Transduction by AAV.

Adeno-associated viruses (AAVs) have recently emerged as the leading vector for retinal gene therapy. However, AAV vectors which are capable of achieving clinically relevant levels of transgene expression and widespread retinal transduction are still an unmet need. Using rationally designed AAV2-based capsid variants, we investigate the role of capsid hydrophilicity and hydrophobicity as it relates to retinal transduction. We show that hydrophilic, single amino acid (aa) mutations (V387R, W502H, E530K, L583R) in AAV2 negatively impact retinal transduction when heparan sulfate proteoglycan (HSPG) binding remains intact. Conversely, addition of hydrophobic point mutations to an HSPG binding deficient capsid (AAV2ΔHS) lead to increased retinal transduction in both mouse and macaque. Our top performing vector, AAV2(4pMut)ΔHS, achieved robust rod and cone photoreceptor (PR) transduction in macaque, especially in the fovea, and demonstrates the ability to spread laterally beyond the borders of the subretinal injection (SRI) bleb. This study both evaluates biophysical properties of AAV capsids that influence retinal transduction, and assesses the transduction and tropism of a novel capsid variant in a clinically relevant animal model.ImportanceRationally guided engineering of AAV capsids aims to create new generations of vectors with enhanced potential for human gene therapy. By applying rational design principles to AAV2-based capsids, we evaluated the influence of hydrophilic and hydrophobic amino acid (aa) mutations on retinal transduction as it relates to vector administration route. Through this approach we identified a largely deleterious relationship between hydrophilic aa mutations and canonical HSPG binding by AAV2-based capsids. Conversely, the inclusion of hydrophobic aa substitutions on a HSPG binding deficient capsid (AAV2ΔHS), generated a vector capable of robust rod and cone photoreceptor (PR) transduction. This vector AAV2(4pMut)ΔHS also demonstrates a remarkable ability to spread laterally beyond the initial subretinal injection (SRI) bleb, making it an ideal candidate for the treatment of retinal diseases which require a large area of transduction.

Novel AAV44.9-Based Vectors Display Exceptional Characteristics for Retinal Gene Therapy.

The majority of inherited retinal diseases (IRDs) are caused by mutations in genes expressed in photoreceptors (PRs). The ideal vector to address these conditions is one that transduces PRs in large areas of retina with the smallest volume/lowest titer possible, and efficiently transduces foveal cones, the cells responsible for acute, daylight vision that are often the only remaining area of functional retina in IRDs. The purpose of our study was to evaluate the retinal tropism and potency of a novel capsid, AAV44.9, and rationally designed derivatives thereof. We found that AAV44.9 and AAV44.9(E531D) transduced retinas of subretinally injected (SRI) mice with higher efficiency than did benchmark AAV5- and AAV8-based vectors. In macaques, highly efficient cone and rod transduction was observed following submacular and peripheral SRI. AAV44.9- and AAV44.9(E531D)-mediated GFP fluorescence extended laterally well beyond SRI bleb margins. Notably, extrafoveal injection (i.e., fovea not detached during surgery) led to transduction of up to 98% of foveal cones. AAV44.9(E531D) efficiently transduced parafoveal and perifoveal cones, whereas AAV44.9 did not. AAV44.9(E531D) was also capable of restoring retinal function to a mouse model of IRD. These novel capsids will be useful for addressing IRDs that would benefit from an expansive treatment area.

Self-disclosure of serostatus by youth who are HIV-positive: a review.

Self-disclosure of serostatus by youth who are HIV-positive has been considered an important objective for preventing transmission and can have positive outcomes including enhancement of social support. This paper reviews the literature on self-disclosure. Several findings are consistent with the literature in adults, including the influence of gender, lower likelihood of disclosure in casual sexual relationships, and the identified barriers of rejection and stigma. Important areas of difference include youth's expressed needs for communication skills and the significant role of the family in influencing the decision to disclose. The findings raise questions about the relationship between disclosure and safe sexual practices in adolescents and moderate the concept of universal psychological gain from disclosure. The implications from the findings are reviewed, including the individual balance of risk versus benefit, practitioner strategies that might influence this balance and enhance the likelihood of positive outcomes following disclosure, and future research directions are discussed.

Intimate partner violence and preschoolers' explicit memory functioning.

This research examines whether parents' intimate partner physical violence (IPV) relates to their preschoolers' explicit memory functioning, whether children's symptoms of hyperarousal mediate this relation, and whether mothers' positive parenting moderates this relation. Participants were 69 mothers and their 4- or 5-year-old child (34 girls). Mothers completed measures of IPV, children's hyperarousal symptoms, parent-child aggression, and positive parenting. Measures of explicit memory functioning were administered to preschoolers. As expected, IPV correlated negatively with preschoolers' performance on explicit memory tasks, even after controlling for parent-child aggression and demographic variables related to preschoolers' memory functioning. Preschoolers' hyperarousal symptoms did not mediate the relation between IPV and explicit memory functioning, but mothers' positive parenting moderated this relation. Specifically, the negative relation between IPV and preschoolers' performance on 2 of the 3 explicit memory tasks was weaker when mothers engaged in higher levels of positive parenting. These findings extend research on IPV and children's adjustment difficulties to explicit memory functioning in preschoolers and suggest that mothers can ameliorate the influence of IPV on preschoolers' memory functioning via their parenting.

Readiness to change among a group of heavy-drinking college students: correlates of readiness and a comparison of measures.

OBJECTIVE: Although several multi-item scales assess readiness to change alcohol consumption, some researchers have proposed that a small number of single-item rulers may assess readiness nearly as well. PARTICIPANTS: In fall 2006 and spring 2007, the authors assessed 279 participants who reported at least 1 heavy drinking episode in the 2 weeks prior to the survey. METHODS: The authors compared answers from the Readiness to Change Questionnaire with rulers measuring importance and confidence regarding change. RESULTS: Importance correlated strongly with readiness to change, whereas confidence correlated negatively and less strongly with readiness. The validity of the importance ruler as a proxy for readiness was supported by its correlations with several measures of patterns of alcohol use, as well as its precursors and consequences. CONCLUSIONS: Given the strong correlation between the importance ruler and the Readiness to Change score, this method may have practical utility as a brief assessment tool. Adding confidence as a second dimension slightly improved the ability to predict readiness.

Cumulating retrieval inhibition in semantic and lexical domains.

In 3 experiments the authors examined changes in successive exemplar generation percentages within categories defined semantically (e.g., fruit-P, fruit-A, fruit-M) and by 1st letter (e.g., insect-C, sport-C, car-C), with a mixed control condition (e.g., fruit-P, insect-C, disease-M). Retrieval success declined across 12 successive items in both semantic and letter categories, with no change for the mixed condition. This retrieval inhibition is unrelated to taxonomic frequency of exemplars within either letter or semantic categorical structures. Furthermore, semantic retrieval inhibition appears to be long lasting, suggested by the decline in retrieval percentage across successive 12-item blocks in both the mixed and letter conditions. The authors suggest that different mechanisms underlie the inhibition found in the semantic (suppression) and letter (interference) conditions.

Children's questions about interparent conflict and violence: what's a mother to say?

This research examined the relation between mothers' responses to children's questions about interparent conflict and children's adjustment. Participants were 134 mothers and their children (70 boys, 64 girls), aged 7 to 10. In each family, an act of intimate-partner violence (IPV) had recently occurred. Mothers' responses to children's questions about interparent conflict were assessed via a semistructured interview coded to reflect the extent to which the mothers' responses addressed the content of the children's questions. Mothers and children reported on physical IPV. Mothers also reported on interparent conflict, parent-child aggression, and maternal warmth. Children's adjustment was assessed via mothers' and children's reports at two time points 6 months apart. The extent to which mothers' responses addressed the content of the children's questions about interparent conflict was negatively associated with children's adjustment problems, after accounting for the frequency of physical IPV, frequency of interparent conflict, parent-child aggression, and maternal warmth. These associations emerged cross-sectionally and prospectively. However, in those prospective analyses that accounted for children's baseline levels of adjustment, maternal responsiveness was not associated with later children's adjustment problems.

Improving the effectiveness of computer-delivered personalized drinking feedback interventions for college students.

This study evaluated methods of enhancing college students' retention of information provided to them in a computer-delivered personalized drinking feedback intervention and whether enhanced retention reduced alcohol consumption during the two-week period following the intervention. Participants were 98 college students who reported at least one heavy drinking episode in the past two weeks. After participating in an online, personalized drinking feedback intervention, students were randomly assigned to one of three experimental conditions: 1) typical, in which they were simply sent home, 2) reading, in which they were asked to spend the next 20 minutes re-reading the feedback, and 3) recall, in which they were asked to spend the next 20 minutes writing down as much of the information from the feedback as they could remember. Two weeks following the intervention, participants completed a recall test and provided information on their alcohol use during the previous two weeks. Results indicated that participants in the reading and recall conditions retained more of the feedback information than did participants in the typical condition. In addition, participants in the reading and recall conditions reported reduced alcohol consumption in the two-week period following the intervention, compared to those in the typical condition. Information retention partially mediated the effects of the reading and recall conditions on drinking outcomes.

Correlates of dating violence among male and female heavy-drinking college students.

OBJECTIVE: To evaluate the correlates for dating violence among heavy-drinking college students. METHOD: Participants were at least 18 years old and reported at least one heavy-drinking episode in the past 2 weeks. RESULTS: After covariate adjustment, estimated peak blood alcohol concentration during the past month was associated with higher victims' verbal-emotional abuse score, and perpetrators' verbal-emotional abuse and threatening abuse scores ( N = 280). In addition, being non-White was significantly associated with higher victims' threatening abuse, physical abuse, and total abuse scores and perpetrators' threatening abuse and physical abuse scores. Moreover, male students had significantly lower victims' threatening abuse and physical abuse scores and perpetrators' threatening abuse scores compared to female students. DISCUSSION: Preventive programs that target dating violence among heavy-drinking college students should consider alcohol use as an important risk factor for abusive behaviors, both for the victims as well as the perpetrators.