Cross-Generational Transmission of Early Life Stress Effects on HPA Regulators and Bdnf Are Mediated by Sex, Lineage, and Upbringing.

Early life stress (ELS) is a potent developmental disruptor and increases the risk for psychopathology. Various forms of ELS have been studied in both humans and rodents, and have been implicated in altered DNA methylation, gene transcription, stress hormone levels, and behavior. Although recent studies have focused on stress-induced epigenetic changes, the extent to which ELS alters HPA axis function and stress responsivity across generations, whether these effects are sex-specific, and how lineage interacts with upbringing to impact these effects, remain unclear. To address these points, two generations of rodents were utilized, with the first generation subjected to ELS via maternal separation, and the second to a balanced cross-fostering paradigm. We hypothesized that ELS would disrupt normative development in both generations, manifesting as altered methylation and expression of genes associated with stress signaling pathways (Nr3c1, Nr3c2, and Bdnf), blunted corticosterone (CORT), and anxiety-like behaviors. Additionally, we expected deficits in the second generation to be modulated by caretaking environment and for the pattern of results to differ between the sexes. Results suggest that direct exposure to ELS leads to sex-specific effects on gene regulation and HPA functioning in adulthood, with maternal separation leading to increases in Bdnf methylation in both sexes, decreases in Bdnf expression in females, and decreases in Nr3c1 methylation in males, as well as blunted CORT and less anxiety-like behavior in females. These alterations converged with caretaking to impart perturbations upon the subsequent generation. Across sex, ELS lineage led to decreased methylation of Nr3c1, and increased methylation of Bdnf. In fostered animals, upbringing by a previously stressed mother interacted with offspring lineage to impact methylation of Nr3c1 and Bdnf. Upbringing was also implicated in altered anxiety-like behavior in males, and baseline CORT levels in females. Such effects may correspond with observed alterations in maternal behavior across groups. In conclusion, ELS conferred enduring sex-specific alterations, both first-hand and trans-generationally via lineage and upbringing. Importantly, lineage of cross-fostered pups was sufficient to normalize or disturb maternal behavior of foster-dams, an observation requiring further elucidation. These results have implications for multi-generational effects of ELS in humans and may motivate early interventions.

Alterations in DNA Methylation Status Associated with Gulf War Illness.

Gulf War Illness (GWI) affects about 25% of Persian Gulf veterans with a cluster of chronic symptoms, including immune dysfunction and neurological issues. Recent studies implicate gene expression changes in immune function to be associated with GWI. Since DNA methylation can regulate such changes in gene expression, and disruption of DNA methylation pattern is implicated in various immune and neurological diseases, we aimed to study the DNA methylation patterns in peripheral blood mononuclear cells from GWI patients. Global DNA methylation levels were similar in GWI patients and controls. However, the genome-wide microarray technology detected 10,767 differentially methylated CpG sites across gene regulatory elements and within coding regions. Approximately 88% of them were hypermethylated in GWI patients. The separate analysis found 776 differentially methylated gene promoters (DMP), which were predominantly hypermethylated. Pyrosequencing validation confirmed microarray results. Functional analysis revealed that majority of the DMPs belonged to genes responsible for metabolism and immune system. This is the first pilot human study characterizing genome-wide epigenetic changes associated with GWI. It suggests a significant contribution of epigenetic dysfunction in GWI. Moreover, it supports the dysregulation of immune function in GWI. Lastly, it suggests studies with the larger cohort to validate our findings.

Identification of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-associated DNA methylation patterns.

BACKGROUND: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex condition involving multiple organ systems and characterized by persistent/relapsing debilitating fatigue, immune dysfunction, neurological problems, and other symptoms not curable for at least 6 months. Disruption of DNA methylation patterns has been tied to various immune and neurological diseases; however, its status in ME/CFS remains uncertain. Our study aimed at identifying changes in the DNA methylation patterns that associate with ME/CFS. METHODS: We extracted genomic DNA from peripheral blood mononuclear cells from 13 ME/CFS study subjects and 12 healthy controls and measured global DNA methylation by ELISA-like method and site-specific methylation status using Illumina MethylationEPIC microarrays. Pyrosequencing validation included 33 ME/CFS cases and 31 controls from two geographically distant cohorts. RESULTS: Global DNA methylation levels of ME/CFS cases were similar to those of controls. However, microarray-based approach allowed detection of 17,296 differentially methylated CpG sites in 6,368 genes across regulatory elements and within coding regions of genes. Analysis of DNA methylation in promoter regions revealed 307 differentially methylated promoters. Ingenuity pathway analysis indicated that genes associated with differentially methylated promoters participated in at least 15 different pathways mostly related to cell signaling with a strong immune component. CONCLUSIONS: This is the first study that has explored genome-wide epigenetic changes associated with ME/CFS using the advanced Illumina MethylationEPIC microarrays covering about 850,000 CpG sites in two geographically distant cohorts of ME/CFS cases and matched controls. Our results are aligned with previous studies that indicate a dysregulation of the immune system in ME/CFS. They also suggest a potential role of epigenetic de-regulation in the pathobiology of ME/CFS. We propose screening of larger cohorts of ME/CFS cases to determine the external validity of these epigenetic changes in order to implement them as possible diagnostic markers in clinical setting.

Effects of a stretching regime on stride length and range of motion in equine trot.

The aim of this study was to quantify the effects of two different 8-week stretching regimes on stride length (SL) and range of motion (ROM) in the equine trot. Eighteen horses were divided into three matched groups: a 6 days/week stretching regime (6DSR), a 3 days/week stretching regime (3DSR) and a control no-stretching regime (NSR). SL and ROM data were collected at weeks 0, 2, 4, 6 and 8 for trot in-hand. Stretching had no significant effect on SL. A number of significant differences were found in joint ROM between treatments in the shoulder, stifle and hock, suggesting some negative biomechanical effects of the 6DSR. Stretching daily may be too intensive and cause delayed onset of muscle soreness. Further examination of stretch frequency may establish its potential to enhance performance and welfare.