Rapamycin Inhibits Senescence and Improves Immunomodulatory Function of Mesenchymal Stem Cells Through IL-8 and TGF-ß Signaling.

Mesenchymal stromal cells (MSCs) grown in high-density monolayers (sheets) are promising vehicles for numerous bioengineering applications. When MSC sheets are maintained in prolonged cultures, they undergo rapid senescence, limiting their downstream efficacy. Although rapamycin is a potential agent that can inhibit senescence in cell cultures, no study has investigated rapamycin's effect on MSCs grown in high-density culture and its effect on downstream target gene expression. In this study, placental-derived MSCs (PMSCs) were seeded at high density to generate PMSC sheets in 24 hours and were then treated with rapamycin or vehicle for up to 7 days. Autophagy activity, cell senescence and apoptosis, cell size and granularity, and senescence-associated cytokines (IL-6 and IL-8) were analyzed. Differential response in gene expression were assessed via microarray analysis. Rapamycin significantly increased PMSC sheet autophagy activity, inhibited cellular senescence, decreased cell size and granularity at all timepoints. Rapamycin also significantly decreased the number of cells in late apoptosis at day 7 of sheet culture, as well as caspase 3/7 activity at all timepoints. Notably, while rapamycin decreased IL-6 secretion, increased IL-8 levels were observed at all timepoints. Microarray analysis further confirmed the upregulation of IL-8 transcription, as well as provided a list of 396 genes with 2-fold differential expression, where transforming growth factor-ß (TGF-ß) signaling were identified as important upregulated pathways. Rapamycin both decreased senescence and has an immunomodulatory action of PMSCs grown in sheet culture, which will likely improve the chemotaxis of pro-healing cells to sites of tissue repair in future bioengineering applications.

Differential effects of pretraining influences on readiness to change.

Training and development are integral to organizational change but are difficult to accomplish effectively in dynamic and complex work environments. Such environments can lead to nonoptimal training conditions that reduce individuals' readiness to change and training effectiveness. On the basis of the transtheoretical model of change (J. O. Prochaska, C. C. DiClemente, & J. C. Norcross, 1992), the authors examined pretraining influences (choice, social support, and motivation to learn) on readiness to change under nonoptimal training conditions. They examined specific dimensions of readiness to change rather than a global readiness to change construct. Participants were 183 driving under the influence (DUI) offenders participating in a court-mandated, alcohol-related Weekend Intervention Program. Perceived choice to attend training, social support, and motivation to learn affected readiness to change when individuals were resisting, considering, acting on, or maintaining behavior or attitude change. These effects were also dependent on age. Results suggest how training effectiveness could be improved when trainees are least likely to learn.

Predicting workers' compensation claims and disciplinary actions using SecureFit®: Further support for integrative models of workplace safety.

INTRODUCTION: A growing body of applied research has identified certain psychological traits that are predictive of worker safety. However, most of these studies suffer from an overreliance on common method bias caused by self-report measures of both: (a) personal factors such as personality traits; and (b) outcomes such as safety behaviors and injuries. METHOD: This study utilized archival data from 796 employees at a large U.S. automobile manufacturer. Data were gathered on a pre-employment assessment, SecureFit®, that measured key personality characteristics such as conscientiousness, locus of control, and risk taking. In addition, objective measures of workers' compensation claims and disciplinary actions were also gathered. RESULTS: The results indicated that disciplinary actions and workers' compensation claims were strongly correlated. It also demonstrated that the pre-employment assessment was able to predict both disciplinary actions and workers' compensation claims up to 12months in the future. Screening out just 8% of the applicant sample using the assessment would have resulted in a 35% reduction in disciplinary actions and 46% in workers' compensation claims, respectively. CONCLUSIONS: The study found a very strong relationship between counterproductive work behaviors (CWBs), such as not following rules, and workers' compensation claims. It also found a strong relationship between a combination of personality traits that have been shown to be associated with both variables, although the current study was able to demonstrate that relationship with objective measure of both variables. PRACTICAL APPLICATIONS: Individuals who receive disciplinary actions for things such as not following rules, not coming to work on time, etc. are significantly more likely to also be involved in serious safety incidents, and vice versa. Identifying those individuals early on in the hiring process and screening them out can significantly reduce the number of CWBs as well as workers' compensation claims.

Uncovering curvilinear relationships between conscientiousness and job performance: how theoretically appropriate measurement makes an empirical difference.

The personality trait of conscientiousness has seen considerable attention from applied psychologists due to its efficacy for predicting job performance across performance dimensions and occupations. However, recent theoretical and empirical developments have questioned the assumption that more conscientiousness always results in better job performance, suggesting a curvilinear link between the 2. Despite these developments, the results of studies directly testing the idea have been mixed. Here, we propose this link has been obscured by another pervasive assumption known as the dominance model of measurement: that higher scores on traditional personality measures always indicate higher levels of conscientiousness. Recent research suggests dominance models show inferior fit to personality test scores as compared to ideal point models that allow for curvilinear relationships between traits and scores. Using data from 2 different samples of job incumbents, we show the rank-order changes that result from using an ideal point model expose a curvilinear link between conscientiousness and job performance 100% of the time, whereas results using dominance models show mixed results, similar to the current state of the literature. Finally, with an independent cross-validation sample, we show that selection based on predicted performance using ideal point scores results in more favorable objective hiring outcomes. Implications for practice and future research are discussed.