Browsing by Author "Schrott, Rose"
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Item Open Access Cannabinoid exposure and altered DNA methylation in rat and human sperm.(Epigenetics, 2018-01) Murphy, Susan K; Itchon-Ramos, Nilda; Visco, Zachary; Huang, Zhiqing; Grenier, Carole; Schrott, Rose; Acharya, Kelly; Boudreau, Marie-Helene; Price, Thomas M; Raburn, Douglas J; Corcoran, David L; Lucas, Joseph E; Mitchell, John T; McClernon, F Joseph; Cauley, Marty; Hall, Brandon J; Levin, Edward D; Kollins, Scott HLittle is known about the reproductive effects of paternal cannabis exposure. We evaluated associations between cannabis or tetrahydrocannabinol (THC) exposure and altered DNA methylation in sperm from humans and rats, respectively. DNA methylation, measured by reduced representation bisulfite sequencing, differed in the sperm of human users from non-users by at least 10% at 3,979 CpG sites. Pathway analyses indicated Hippo Signaling and Pathways in Cancer as enriched with altered genes (Bonferroni p < 0.02). These same two pathways were also enriched with genes having altered methylation in sperm from THC-exposed versus vehicle-exposed rats (p < 0.01). Data validity is supported by significant correlations between THC exposure levels in humans and methylation for 177 genes, and substantial overlap in THC target genes in rat sperm (this study) and genes previously reported as having altered methylation in the brain of rat offspring born to parents both exposed to THC during adolescence. In humans, cannabis use was also associated with significantly lower sperm concentration. Findings point to possible pre-conception paternal reproductive risks associated with cannabis use.Item Open Access Cannabis use and the sperm epigenome: a budding concern?(Environmental epigenetics, 2020-01) Schrott, Rose; Murphy, Susan KThe United States is swiftly moving toward increased legalization of medical and recreational cannabis. Currently considered the most commonly used illicit psychoactive drug, recreational cannabis is legal in 11 states and Washington, DC, and male use is an important and understudied concern. Questions remain, however, about the potential long-term consequences of this exposure and how cannabis might impact the epigenetic integrity of sperm in such a way that could influence the health and development of offspring. This review summarizes cannabis use and potency in the USA, provides a brief overview of DNA methylation as an epigenetic mechanism that is vulnerable in sperm to environmental exposures including cannabis, and summarizes studies that have examined the effects of parental exposure to cannabis or delta-9 tetrahydrocannabinol (THC, the main psychoactive component of cannabis) on the epigenetic profile of the gametes and behavior of offspring. These studies have demonstrated significant changes to the sperm DNA methylome following cannabis use in humans, and THC exposure in rats. Furthermore, the use of rodent models has shown methylation and behavioral changes in rats born to fathers exposed to THC or synthetic cannabinoids, or to parents who were both exposed to THC. These data substantiate an urgent need for additional studies assessing the effects of cannabis exposure on childhood health and development. This is especially true given the current growing state of cannabis use in the USA.Item Open Access Cannabis use is associated with potentially heritable widespread changes in autism candidate gene DLGAP2 DNA methylation in sperm.(Epigenetics, 2020-01) Schrott, Rose; Acharya, Kelly; Itchon-Ramos, Nilda; Hawkey, Andrew B; Pippen, Erica; Mitchell, John T; Kollins, Scott H; Levin, Edward D; Murphy, Susan KParental cannabis use has been associated with adverse neurodevelopmental outcomes in offspring, but how such phenotypes are transmitted is largely unknown. Using reduced representation bisulphite sequencing (RRBS), we recently demonstrated that cannabis use is associated with widespread DNA methylation changes in human and rat sperm. Discs-Large Associated Protein 2 (DLGAP2), involved in synapse organization, neuronal signaling, and strongly implicated in autism, exhibited significant hypomethylation (p < 0.05) at 17 CpG sites in human sperm. We successfully validated the differential methylation present in DLGAP2 for nine CpG sites located in intron seven (p < 0.05) using quantitative bisulphite pyrosequencing. Intron 7 DNA methylation and DLGAP2 expression in human conceptal brain tissue were inversely correlated (p < 0.01). Adult male rats exposed to delta-9-tetrahydrocannabinol (THC) showed differential DNA methylation at Dlgap2 in sperm (p < 0.03), as did the nucleus accumbens of rats whose fathers were exposed to THC prior to conception (p < 0.05). Altogether, these results warrant further investigation into the effects of preconception cannabis use in males and the potential effects on subsequent generations.Item Open Access Epigenetic alterations in cytochrome P450 oxidoreductase (Por) in sperm of rats exposed to tetrahydrocannabinol (THC).(Scientific reports, 2020-07-23) Acharya, Kelly S; Schrott, Rose; Grenier, Carole; Huang, Zhiqing; Holloway, Zade; Hawkey, Andrew; Levin, Edward D; Murphy, Susan KAs marijuana legalization is increasing, research regarding possible long-term risks for users and their offspring is needed. Little data exists on effects of paternal tetrahydrocannabinol (THC) exposure prior to reproduction. This study determined if chronic THC exposure alters sperm DNA methylation (DNAm) and if such effects are intergenerationally transmitted. Adult male rats underwent oral gavage with THC or vehicle control. Differentially methylated (DM) loci in motile sperm were identified using reduced representation bisulfite sequencing (RRBS). Another cohort was injected with vehicle or THC, and sperm DNAm was analyzed. Finally, THC-exposed and control adult male rats were mated with THC-naïve females. DNAm levels of target genes in brain tissues of the offspring were determined by pyrosequencing. RRBS identified 2,940 DM CpGs mapping to 627 genes. Significant hypermethylation was confirmed (p < 0.05) following oral THC administration for cytochrome P450 oxidoreductase (Por), involved in toxin processing and disorders of sexual development. Por hypermethylation was not observed after THC injection or in the subsequent generation. These results support that THC alters DNAm in sperm and that route of exposure can have differential effects. Although we did not observe evidence of intergenerational transmission of the DNAm change, larger studies are required to definitively exclude this possibility.Item Open Access Male obesity impacts DNA methylation reprogramming in sperm.(Clinical epigenetics, 2021-01-25) Keyhan, Sanaz; Burke, Emily; Schrott, Rose; Huang, Zhiqing; Grenier, Carole; Price, Thomas; Raburn, Doug; Corcoran, David L; Soubry, Adelheid; Hoyo, Catherine; Murphy, Susan KBackground
Male obesity has profound effects on morbidity and mortality, but relatively little is known about the impact of obesity on gametes and the potential for adverse effects of male obesity to be passed to the next generation. DNA methylation contributes to gene regulation and is erased and re-established during gametogenesis. Throughout post-pubertal spermatogenesis, there are continual needs to both maintain established methylation and complete DNA methylation programming, even during epididymal maturation. This dynamic epigenetic landscape may confer increased vulnerability to environmental influences, including the obesogenic environment, that could disrupt reprogramming fidelity. Here we conducted an exploratory analysis that showed that overweight/obesity (n = 20) is associated with differences in mature spermatozoa DNA methylation profiles relative to controls with normal BMI (n = 47).Results
We identified 3264 CpG sites in human sperm that are significantly associated with BMI (p < 0.05) using Infinium HumanMethylation450 BeadChips. These CpG sites were significantly overrepresented among genes involved in transcriptional regulation and misregulation in cancer, nervous system development, and stem cell pluripotency. Analysis of individual sperm using bisulfite sequencing of cloned alleles revealed that the methylation differences are present in a subset of sperm rather than being randomly distributed across all sperm.Conclusions
Male obesity is associated with altered sperm DNA methylation profiles that appear to affect reprogramming fidelity in a subset of sperm, suggestive of an influence on the spermatogonia. Further work is required to determine the potential heritability of these DNA methylation alterations. If heritable, these changes have the potential to impede normal development.Item Open Access Refraining from use diminishes cannabis-associated epigenetic changes in human sperm.(Environmental epigenetics, 2021-01) Schrott, Rose; Murphy, Susan K; Modliszewski, Jennifer L; King, Dillon E; Hill, Bendu; Itchon-Ramos, Nilda; Raburn, Douglas; Price, Thomas; Levin, Edward D; Vandrey, Ryan; Corcoran, David L; Kollins, Scott H; Mitchell, John TCannabis use alters sperm DNA methylation, but the potential reversibility of these changes is unknown. Semen samples from cannabis users and non-user controls were collected at baseline and again following a 77-day period of cannabis abstinence (one spermatogenic cycle). Users and controls did not significantly differ by demographics or semen analyses. Whole-genome bisulfite sequencing identified 163 CpG sites with significantly different DNA methylation in sperm between groups (P < 2.94 × 10-9). Genes associated with altered CpG sites were enriched with those involved in development, including cardiogenesis and neurodevelopment. Many of the differences in sperm DNA methylation between groups were diminished after cannabis abstinence. These results indicate that sustained cannabis abstinence significantly reduces the number of sperm showing cannabis-associated alterations at genes important for early development.Item Open Access Sperm DNA methylation alterations from cannabis extract exposure are evident in offspring.(Epigenetics & chromatin, 2022-09) Schrott, Rose; Modliszewski, Jennifer L; Hawkey, Andrew B; Grenier, Carole; Holloway, Zade; Evans, Janequia; Pippen, Erica; Corcoran, David L; Levin, Edward D; Murphy, Susan KBackground
Cannabis legalization is expanding and men are the predominant users. We have limited knowledge about how cannabis impacts sperm and whether the effects are heritable.Results
Whole genome bisulfite sequencing (WGBS) data were generated for sperm of rats exposed to: (1) cannabis extract (CE) for 28 days, then 56 days of vehicle only (~ one spermatogenic cycle); (2) vehicle for 56 days, then 28 days of CE; or (3) vehicle only. Males were then mated with drug-naïve females to produce F1 offspring from which heart, brain, and sperm tissues underwent analyses. There were 3321 nominally significant differentially methylated CpGs in F0 sperm identified via WGBS with select methylation changes validated via bisulfite pyrosequencing. Significant methylation changes validated in F0 sperm of the exposed males at the gene 2-Phosphoxylose Phosphatase 1 (Pxylp1) were also detectable in their F1 sperm but not in controls. Changes validated in exposed F0 sperm at Metastasis Suppressor 1-Like Protein (Mtss1l) were also present in F1 hippocampal and nucleus accumbens (NAc) of the exposed group compared to controls. For Mtss1l, a significant sex-specific relationship between DNA methylation and gene expression was demonstrated in the F1 NAc. Phenotypically, rats born to CSE-exposed fathers exhibited significant cardiomegaly relative to those born to control fathers.Conclusions
This is the first characterization of the effect of cannabis exposure on the entirety of the rat sperm methylome. We identified CE-associated methylation changes across the sperm methylome, some of which persisted despite a "washout" period. Select methylation changes validated via bisulfite pyrosequencing, and genes associated with methylation changes were involved in early developmental processes. Preconception CE exposure is associated with detectable changes in offspring DNA methylation that are functionally related to changes in gene expression and cardiomegaly. These results support that paternal preconception exposure to cannabis can influence offspring outcomes.Item Open Access Sperm DNA methylation altered by THC and nicotine: Vulnerability of neurodevelopmental genes with bivalent chromatin.(Scientific reports, 2020-09) Schrott, Rose; Rajavel, Maya; Acharya, Kelly; Huang, Zhiqing; Acharya, Chaitanya; Hawkey, Andrew; Pippen, Erica; Lyerly, H Kim; Levin, Edward D; Murphy, Susan KMen consume the most nicotine and cannabis products but impacts on sperm epigenetics are poorly characterized. Evidence suggests that preconception exposure to these drugs alters offspring neurodevelopment. Epigenetics may in part facilitate heritability. We therefore compared effects of exposure to tetrahydrocannabinol (THC) and nicotine on DNA methylation in rat sperm at genes involved in neurodevelopment. Reduced representation bisulfite sequencing data from sperm of rats exposed to THC via oral gavage showed that seven neurodevelopmentally active genes were significantly differentially methylated versus controls. Pyrosequencing data revealed majority overlap in differential methylation in sperm from rats exposed to THC via injection as well as those exposed to nicotine. Neurodevelopmental genes including autism candidates are vulnerable to environmental exposures and common features may mediate this vulnerability. We discovered that autism candidate genes are significantly enriched for bivalent chromatin structure, suggesting this configuration may increase vulnerability of genes in sperm to disrupted methylation.