Biology subjects

Lewis, C. R.

Publications and source records attributed to Lewis, C. R..

3 recordsLinked to original sources

bioRxiv2026

System-Specific Epigenetic Aging Signatures in Autistic Adults

Background: Autism is a lifelong neurodevelopmental condition, but the biological processes shaping aging are poorly understood. DNA methylation-based measures index physiological decline and mortality risk independently of chronological age. We tested whether biological aging differs in autistic adults, whether differences are system-specific, and which factors predict within-autism variation. Methods: Saliva DNA methylation (Illumina EPIC) was assayed in 37 autistic adults (31 male, 6 female; mean age 29.8 years), followed from early childhood, spanning a broad ability range including intellectual disability, and 188 non-autistic adults from four public datasets, processed jointly. Fifteen measures were calculated: four global (Horvath, GrimAge, DunedinPACE, SystemsAge) and 11 system-specific SystemsAge subscores. Models adjusted for age, sex, and epithelial-cell proportion. Results: Global aging measures did not differ between groups (all q > .34). However, autistic adults had higher Brain ({beta} = 0.81), Blood ({beta} = 0.65), and Liver SystemsAge ({beta} = 0.58; all q < .01), with Brain and Blood robust across sensitivity analyses. Within autism, aging measures were unrelated to symptom severity, IQ, co-occurring diagnoses, or medication use. Instead, elevations were associated with psychosocial circumstances, including a lack of structured daytime activity, greater loneliness, and lower quality of life. Conclusions: Differences in aging biology in autism appeared system-specific rather than global, with no evidence of generalized epigenetic age acceleration. This vulnerability appeared more closely tied to psychosocial factors than core clinical features. System-specific DNAm measures may therefore provide a more sensitive framework for identifying biological heterogeneity and potentially modifiable contributors to healthy aging in autistic adulthood.

genomics↗

bioRxiv2025

Brain-epigenome wide association study (BEWAS) on the effects of two emerging psychedelics: ketamine & MDMA

Psychedelic compounds such as ketamine and MDMA have shown therapeutic promise for mood and trauma-related disorders, yet their molecular mechanisms remain unclear. This study applied a Brain-Epigenome-Wide Association Study (BEWAS) to assess DNA methylation changes in brain-enriched genes following treatment. Pre- and post-treatment blood (ketamine, N = 20) and saliva (MDMA, N = 16) samples from clinical trial participants were analyzed. Ketamine altered methylation at 1,210 CpG sites; MDMA affected 2,074 CpG sites. Functional enrichment analyses revealed changes in genes involved in neuroplasticity, immune regulation, and mental processes. Overlapping effects were observed in genes such as PTPRN2 and SHANK2, suggesting shared epigenetic mechanisms in driving increased neuroplasticity. These findings highlight psychedelics capacity to induce coordinated, lasting molecular changes relevant to neuroimmune function and psychiatric health.

genomics↗

bioRxiv2025

Cas10 residues lining the target RNA binding channel regulate interference by distinguishing cognate target RNA from mismatched targets

Type III CRISPR systems are defined by the presence of the Cas10 protein and are among the most abundant CRISPR systems in nature. Cas10 forms a complex with crRNA and several Cas proteins that surveils bacterial cells for foreign RNA molecules and when they are detected it activates a cascade of interference activities. The synthesis of the cyclic oligoadenylate signaling molecule by Cas10 is a key aspect of the interference cascade. Despite structures of the Cas10 complex bound to target RNAs, the molecular mechanism by which Cas10 senses the bound state to license interference is lacking. We identified five residues in S. epidermidis Cas10, two in the Cas10 Palm2 domain and three in domain 4, that line the target RNA binding channel. We assessed the contribution of these residues to interference in the context of a cognate or mismatched target RNA. We found that the residues regulate whether a mismatched crRNA-target RNA duplex is able to activate interference in vivo. We purified two site-directed mutants of Cas10-Csm and show with in vitro cOA synthesis assays they demonstrate enhanced discrimination of cognate versus mismatched targets.

molecular biology↗