Merging the fields of epigenetics and human behavior is potentially "game changing" and provides an unprecedented opportunity to discover the molecular basis of human behavior. The goal of this mentored clinical scientist research career development award (K08) is to facilitate the candidate's development as an independent investigator specializing in epigenetic influences on infant developmental processes. [The candidate's training to date has incorporated infant physiology, early caregiving experiences, and their interaction, to investigate the development of the human stress response. But how do these early caregiving experiences become biologically embedded to explain individual variability in the response to stress? Can the study of epigenetics explain the development of normal and disordered phenotypes early in life, when the stress response is particularly malleable to early intervention?] The training and research proposed will allow the candidate to begin to answer these questions and help the candidate achieve her long-term career goal of establishing an independent research program focused on the role of epigenetic influences on normal and disordered infant and child development. Both animal (Liu et al., 1997) and human (Albers, Riksen-Walraven, Sweep, &de Weerth, 2008;Kaplan, Evans, &Monk, 2008) models demonstrate that the quality of parental caregiving affects individual susceptibility to illness throughout life, above and beyond infant temperament (Hane &Fox, 2006). Parental caregiving in infancy is typically described as a continuum ranging from caregiving sensitivity to insensitivity. Parental insensitivity is thought of as a type of early life stress that is associatd greater expressions of infant physiological reactivity. Protracted responses to stress in the form of greater physiological reactivity are in turn related to vulnerability for mental illness, diabets, obesity, and heart disease (Felitti et al., 1998;McEwen, 1998). At present, we lack clarity about how parental insensitivity translates into bio-behavioral vulnerability, though the infancy period s of particular interest given how receptive the stress system is to environmental signals (Levine, 1994). The current K08 application will examine epigenetic processes involved in the association between parenting and the infant's physiological stress response. If, as we expect, parental caregiving behavior does "calibrate" the infant stress response, this finding will impact public health in two ways, by: (1) using this basic science knowledge to support future translational work on early interventions to increase sensitive parenting which will;(2) lead to the development of targeted behavioral interventions. We know little about how the human infant stress response develops, despite evidence that: (1) both maternal caregiving behavior and epigenetic processes shape infant stress reactivity in rodents (Meaney, 2001);(2) a "reactive" infant who is reared in an adverse environment is at high risk for medical and psychological morbidity (Boyce &Ellis, 2005). The purpose of this project is to determine if similar processes occur in human infants, beyond infants'own temperamentally-based responses to stress.
The aims are to: (1) evaluate the relations between maternal caregiving behavior and epigenetic alterations in candidate genes in their infants, (2) assess the relation between maternal caregiving behavior and infant physiological stress reactivity across neuroendocrine, sympathetic, and parasympathetic systems, and (3) examine the relations between maternal caregiving behavior, epigenetic alterations in candidate genes, and infant physiological stress reactivity. Translating what is known in animals to the human stress response makes this project particularly innovative. Success in this new research area is dependent upon focused mentored training and research experiences. The candidate's career development plan capitalizes on a promising opportunity to receive mentoring from a multidisciplinary team of experts who will support the candidate's career development and help her achieve her short-term goals for training in: (1) epigenetics, specifically behavioral epigenetics, (2) epigenetic laboratory methods, (3) the neuroendocrine response, particularly in relation to epigenetic changes, (4) statistical approaches to epigenetic data [and bioinformatics], and (5) professional development. This training is facilitated by a mentorship team led by Dr. Barry Lester. Dr. Lester is a developmental psychologist working at the forefront of human behavioral epigenetics, specifically in relation to infant neurobehavioral development. Dr. Lester collaborates closely with Dr. Carmen Marsit (co-mentor), a molecular biologist and epidemiologist and expert in the epigenetic regulation of the genome. Dr. Linda Carpenter (co-mentor) is a nationally recognized expert in the neuroendocrine and neurobehavioral stress response. She will provide training in the HPA system with an emphasis on epigenetics. [Dr. Uzun (consultant) will provide training in bioinformatics.] The training and research proposed will serve as the basis for a series of R01 applications spanning the basic science of behavioral epigenetics as it relates to the infant's physiological stress response.
The quality of parental caregiving affects an individual's susceptibility to psychological and medical illness throughout life, presumably via how the individual responds to stress. We will examine the links between early caregiving experiences and the infant's response to stress, including the role of epigenetic processes, to identify which infants may be most susceptible to these caregiving experiences. This knowledge in turn may lead to the development of intervention research and programs to prevent the onset of behavioral and perhaps medical problems.