Biology subjects

Maxim, Z. L.

Publications and source records attributed to Maxim, Z. L..

3 recordsLinked to original sources

bioRxiv2026

Hierarchical Transcriptomic and Epigenetic Recovery and Remodeling in the Developing Hippocampus Following Early-life Environmental Insults: An Iron Deficiency Rat Model

BackgroundsEarly-life environmental insults cause persistent neurodevelopmental abnormalities accompanied by transcriptional and epigenetic dysregulation despite removal of the original insult or postnatal intervention. However, transcriptomic and epigenomic responses to developmental insults and subsequent treatment during active neurodevelopment remain insufficiently characterized. Developmental iron deficiency (ID) provides a unique model for investigating this question because iron is an essential cofactor for TET DNA dioxygenases and developmental ID causes persistent behavioral and molecular alterations despite iron repletion. ResultsWe integrated the hippocampal transcriptome, DNA methylome (5mC), and hydroxymethylome (5hmC) in male rats at postnatal day 15 following developmental ID and postnatal iron treatment, using Oxford Nanopore sequencing for native DNA modification profiling. Developmental ID induced substantial transcriptional and epigenetic alterations associated with synaptic function, neurodevelopment, and neuroinflammation. Postnatal iron treatment induced a hierarchical response across molecular layers: while transcriptomic alterations largely normalized, 5mC showed only partial recovery, and 5hmC showed extensive de novo modifications. Recovered, persistent, and newly emerged epigenetic marks were associated with increasingly specialized biological functions, from broad neurodevelopmental processes to specific pathways. Furthermore, while 5mC enrichment was associated with transcriptionally suppressed pathways, 5hmC enrichment showed weaker coupling with concurrent transcriptomic activity, suggesting epigenetic poising rather than immediate transcriptional output. MergeOmics integration identified key driver genes showing post-treatment epigenetic regulation despite transcriptional recovery. ConclusionsMolecular recovery following developmental ID extends beyond transcriptomic normalization, involving persistent and extensive epigenetic remodeling. This study provides a framework for understanding molecular responses following early-life environmental insults and highlights the importance of delineating persistent regulatory reprogramming.

genomics↗

bioRxiv2025

Brain-derived exosome biomarkers of neuroinflammation and neuronal functional iron deficiency in newborns of overweight-obese mothers

BackgroundNon-infectious neuroinflammation (NINI) in early life and neonatal neural iron deficiency (nID) have been proposed to contribute to neurodevelopmental dysfunction and disorders, including autism, through toxic effects on neural cells and impaired molecular signaling. Early detection of NINI and nID may enable interventions to restore neurodevelopmental homeostasis and reduce long-term impact. However, such diagnoses are impossible due to ethical reason to access to the central nervous system (e.g., lumbar puncture) when there is no suspicion of brain infection (e.g., meningitis). MethodsWe refined a methodology to isolate and quantify inflammatory and iron-regulatory proteins in high-quality brain-derived extracellular vesicles (BDEVs) from human umbilical cord blood. A preclinical model was used to validate that BDEV contents reflect the brain microenvironment. We then applied this approach to evaluate biomarkers of NINI and nID in BDEVs isolated from cord plasma of newborns of mothers with obesity, a non-infectious pro-inflammatory gestational condition and a risk factor for nID. FindingsPlasma BDEV analytes correlated more strongly with brain analytes and showed stronger associations among functionally related molecules compared with whole plasma analytes. Maternal obesity induced an anti-inflammatory response in the brain compartment, a pro-inflammatory response in the periphery, and functional nID. InterpretationBDEVs may provide a more sensitive representation of the brain microenvironment than blood-based measures (e.g., plasma), enabling non-invasive, early detection of infants with NINI and neonatal nID. FundingSupported by NIH, the Masonic Institute for Developing Brain, Hennepin Healthcare Research Institute, UnityPoint Health Meriter Foundation, and American Academy of Pediatrics Resident Research Grant. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSPrevious studies hypothesized that gestational inflammatory environments (e.g., maternal obesity) increase risk of neonatal neural iron deficiency (nID), neuroinflammation, and neurodevelopmental disorders. However, assessing non-infectious neuroinflammation (NINI) in infants from these high-risk groups is not feasible or clinically justifiable using invasive methods (e.g., cerebrospinal fluid collection), and analytes from whole blood or plasma may not accurately reflect brain physiological status. Added value of this studyWe refined a protocol to isolate brain-derived extracellular vesicles (BDEVs) from a small amount of plasma sample (100 {micro}L) and characterized their contents to approximate brain physiology. We demonstrated that BDEVs more accurately reflect brain status compared with whole plasma. In newborns of mothers with obesity during pregnancy, we found evidence of a low-grade peripheral inflammation accompanied by a protective anti-inflammatory response in the brain. Maternal obesity was also found to induce neonatal nID. Implications of all the available evidenceBDEVs can serve as an accurate, non-invasive tool to assess brain condition. In clinical settings, this approach may be used for early diagnosis, monitoring disease progression, and evaluating treatment effects. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/648967v2_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@108caa9org.highwire.dtl.DTLVardef@311ecdorg.highwire.dtl.DTLVardef@dd4086org.highwire.dtl.DTLVardef@1b747ea_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2024

Differential gene expression and chromatin accessibility in the rat medial prefrontal cortex mediating individual variability in vulnerability to opioid use

We characterized gene transcriptional activity in the medial prefrontal cortex of rats associated with individual differences in vulnerability to three distinct phases of opioid use disorder (OUD). Resilient rats showed many more changes in canonical pathway activity than Vulnerable rats in models of both early and advanced OUD, involving passive opioid exposure and opioid self-administration (SA), respectively. The Resilient/Vulnerable phenotype was also associated across phases with functionally specific gene networks, including those mediating epigenetic, neuroimmune, and neuroplasticity function. In contrast, we identified two phase-specific effects. First, differential activity of a myelination-related gene network was associated with Resilience/Vulnerability measured after passive morphine exposure. Second, expression of the calmodulin-inhibitor Pcp4, a gene recently implicated in a rat opioid SA GWAS analysis, was associated with Resilience/Vulnerability measured after SA but not after passive morphine exposure. Thus, we have identified both general and phase-specific transcriptional signatures involved in OUD vulnerability across its trajectory. TeaserAdaptations in the brain transcriptome are associated with resilience and vulnerability to opioid use disorder.

neuroscience↗