Adolescent peer struggles predict accelerated epigenetic aging in midlife.

This study examined struggles to establish autonomy and relatedness with peers in adolescence and early adulthood as predictors of advanced epigenetic aging assessed at age 30. Participants (N = 154; 67 male and 87 female) were observed repeatedly, along with close friends and romantic partners, from ages 13 through 29. Observed difficulty establishing close friendships characterized by mutual autonomy and relatedness from ages 13 to 18, an interview-assessed attachment state of mind lacking autonomy and valuing of attachment at 24, and self-reported difficulties in social integration across adolescence and adulthood were all linked to greater epigenetic age at 30, after accounting for chronological age, gender, race, and income. Analyses assessing the unique and combined effects of these factors, along with lifetime history of cigarette smoking, indicated that each of these factors, except for adult social integration, contributed uniquely to explaining epigenetic age acceleration. Results are interpreted as evidence that the adolescent preoccupation with peer relationships may be highly functional given the relevance of such relationships to long-term physical outcomes.

Lifetime marijuana use and epigenetic age acceleration: A 17-year prospective examination.

AIMS: This study was designed to assess links between lifetime levels of marijuana use and accelerated epigenetic aging. DESIGN: Prospective longitudinal study, following participants annually from age 13 to age 30. SETTING AND PARTICIPANTS: A community sample of 154 participants recruited from a small city in the Southeastern United States. MEASUREMENTS: Participants completed annual assessments of marijuana use from age 13 to age 29 and provided blood samples that yielded two indices of epigenetic aging (DNAmGrimAge and DunedinPoAm) at age 30. Additional covariates examined included history of cigarette smoking, anxiety and depressive symptoms, childhood illness, gender, adolescent-era family income, and racial/ethnic minority status. FINDINGS: Lifetime marijuana use predicted accelerated epigenetic aging, with effects remaining even after covarying cell counts, demographic factors and chronological age (ß's = 0.32 & 0.27, p's < 0.001, 95% CI's = 0.21-0.43 & 0.16-0.39 for DNAmGrimAge and DunedinPoAm, respectively). Predictions remained after accounting for cigarette smoking (ß's = 0.25 & 0.21, respectively, p's < 0.001, 95% CI's = 0.14-0.37 & 0.09-0.32 for DNAmGrimAge and DunedinPoAm, respectively). A dose-response effect was observed and there was also evidence that effects were dependent upon recency of use. Effects of marijuana use appeared to be fully mediated by hypomethylation of a site linked to effects of hydrocarbon inhalation (cg05575921). CONCLUSIONS: Marijuana use predicted epigenetic changes linked to accelerated aging, with evidence suggesting that effects may be primarily due to hydrocarbon inhalation among marijuana smokers. Further research is warranted to explore mechanisms underlying this linkage.

ROCK insufficiency attenuates ozone-induced airway hyperresponsiveness in mice.

Ozone causes airway hyperresponsiveness (AHR) and pulmonary inflammation. Rho kinase (ROCK) is a key regulator of smooth muscle cell contraction and inflammatory cell migration. To determine the contribution of the two ROCK isoforms ROCK1 and ROCK2 to ozone-induced AHR, we exposed wild-type, ROCK1(+/-), and ROCK2(+/-) mice to air or ozone (2 ppm for 3 h) and evaluated mice 24 h later. ROCK1 or ROCK2 haploinsufficiency did not affect airway responsiveness in air-exposed mice but significantly reduced ozone-induced AHR, with a greater reduction in ROCK2(+/-) mice despite increased bronchoalveolar lavage (BAL) inflammatory cells in ROCK2(+/-) mice. Compared with wild-type mice, ozone-induced increases in BAL hyaluronan, a matrix protein implicated in ozone-induced AHR, were lower in ROCK1(+/-) but not ROCK2(+/-) mice. Ozone-induced increases in other inflammatory moieties reported to contribute to ozone-induced AHR (IL-17A, osteopontin, TNFα) were not different in wild-type vs. ROCK1(+/-) or ROCK2(+/-) mice. We also observed a dose-dependent reduction in ozone-induced AHR after treatment with the ROCK1/ROCK2 inhibitor fasudil, even though fasudil was administered after induction of inflammation. Ozone increased pulmonary expression of ROCK2 but not ROCK1 or RhoA. A ROCK2 inhibitor, SR3677, reduced contractile forces in primary human airway smooth muscle cells, confirming a role for ROCK2 in airway smooth muscle contraction. Our results demonstrate that ozone-induced AHR requires ROCK. Whereas ROCK1-dependent changes in hyaluronan may contribute to ROCK1's role in O3-induced AHR, the role of ROCK2 is downstream of inflammation, likely at the level of airway smooth muscle contraction.