Genome-wide DNA methylation analysis of dogs with high lead exposure living near a lead mining area in Kabwe, Zambia

Nuclear morphology, chromatin compaction, and epigenetic changes in lymphocytes of dogs infected with Ehrlichia canis

Canine monocytic ehrlichiosis (CME), induced by Ehrlichia canis, is an important infectious disease in dogs, characterized by various clinical signs and consequent immune dysfunction. This study aimed to characterize nuclear morphology, chromatin compaction, histone H3 acetylation, and DNA methylation in lymphocytes from dogs naturally infected with E. canis, compared with healthy controls. A total of 30 dogs were included in this study, comprising 15 healthy dogs and 15 dogs with confirmed E. canis infection, verified through polymerase chain reaction. Blood samples were collected from these dogs to isolate peripheral blood mononuclear cells. The isolated cells were prepared into smears and stained using the Feulgen reaction for subsequent analysis. These stained smears underwent video imaging analysis to assess nuclear morphology and chromatin parameters. Additionally, lymphocytes isolated from the PBMCs were analyzed to quantify global levels of histone H3 acetylation and DNA methylation. The results indicated significant increases in nuclear size and alterations in chromatin architecture in the lymphocytes of dogs with E. canis infection. A significant reduction in histone H3 acetylation was observed in this group, suggesting a potential mechanism of transcriptional repression. In contrast, no significant differences in DNA methylation were detected between the infected dogs and the healthy controls. In conclusion, our findings reveal distinct morphological and epigenetic alterations in lymphocytes associated with E. canis infection, thereby enhancing the understanding of the immune dysfunction observed in dogs with CME.

Sex dependent intergenerational effects of lead in mouse model

Lead (Pb) exposure negatively impacts fertility in both males and females, pregnancy outcomes, and child brain development. We investigated the reproductive and neurological effects of Pb exposure on male and female mice via Pb-contaminated soil for 4 weeks. Breeding was conducted after completion of exposure, in four groups; group 1 consisted of exposed dams and unexposed sires, group 2 consisted of exposed sires and unexposed dams, group 3 consisted of exposed sires and exposed dams and group 4 was the control. Generally, Pb exposure reduced observed conception rates, with a cumulative decrement observed when both males and females are exposed. Gene expression of the testes revealed oxidative stress as the cause of reduced conception rates. Neurological tests: Morris water maze and rotarod were conducted on F1 generation offspring. Maternally and paternally exposed F1 mice performed poorly in the Morris water maze when compared to the control. The severity of the neurological effects was also parent-dependent and sex-dependent. Paternal Pb exposure effects were more pronounced in female offspring. A comparison of gene expression changes of the hippocampus and prefrontal cortex showed paternal Pb-exposure resulted in more prefrontal cortex changes than in the hippocampus, a trend also recorded in the exposed sires. The pronounced effects in female offspring of paternal Pb exposure may suggest that Pb neurological effects may be X-chromosome-linked.