Biology subjects

Smith, K. W.

Publications and source records attributed to Smith, K. W..

5 recordsLinked to original sources

bioRxiv2026

Enrichment of methylated cell-free placental DNA

Abstract. Introduction: Preterm birth drives adverse perinatal maternal and infant health outcomes through heterogeneous symptoms, severity, and etiologies. Delivery prior to reaching 37 weeks of gestation may result from medically indicated intervention for pregnancy complications or spontaneously in the absence of prior symptoms. Placental tissue collected following preterm birth exhibits differential DNA methylation compared to full-term placentas and may indicate pregnancy health during gestation. Placental DNA currently has limited utility for assessing health of ongoing pregnancy, as sampling placental tissue during gestation increases the risk of infection and miscarriage. Risks associated with placental sampling during pregnancy limit the use of DNA methylation in clinical preterm birth prediction. Assessing preterm birth risk during gestation requires non-invasive methods for characterizing placental DNA methylation. Results: We quantified genome-wide DNA methylation patterns of hypermethylated cell-free DNA in pregnant (n = 99) and non-pregnant (n = 93) plasma using cell-free methylated DNA immunoprecipitation sequencing (cfMeDIP-seq). In each sample, we assessed DNA methylation status in 300-bp genomic windows, examining both sequencing read counts and calculated absolute molar DNA amount. Known hypermethylated placental regions, including RASSF1, STAT5A, and ERG promoters showed significantly increased odds of detection in pregnant samples, suggesting enrichment of cell-free placental DNA. Of the 536,444 300-bp windows examined, 173,071 (32%) showed significant enrichment in pregnant plasma. Linear modeling identified 107,505 differentially methylated regions (DMRs) associated with pregnancies later diagnosed with intrauterine growth restriction (IUGR) (n = 22). Alu elements showed increased representation in these DMRs than expected, while other repetitive elements exhibited underrepresentation. Discussion: These results demonstrate cfMeDIP-seq's ability to enrich for cell-free placental DNA and characterize cell-free DNA methylation signatures of pregnancies complicated by IUGR. Enrichment of cell-free placental DNA enables non-invasive profiling of placental DNA methylation from maternal plasma. Detectable epigenetic signatures in maternal plasma may identify pregnancies at elevated risk for preterm birth before clinical symptoms appear. Our findings further highlight the potential of cell-free placental DNA for monitoring pregnancy health.

genomics↗

bioRxiv2026

SIMO - Single Section Integrative Multi-Omics - spatial mapping of metabolites and lipids combined with region-specific proteomics in a single tissue slice

Technological advances in biomedical sciences have accelerated multi-omics research, enabling high-resolution spatial mapping of diverse molecular compound classes. However, integrating spatial omics often requires serial tissue sections, limiting the alignment correlation across modalities. We present a single-section integrative multi-omics (SIMO) workflow that combines metabolite and lipid imaging with histopathology and region-specific proteomics. Using MALDI-MSI, tissue staining, and laser microdissection (LMD), SIMO delivers comprehensive metabolic, lipidomic, and proteomic insight from the same sample. Using mouse cardiac tissue we develop, control, and validate the methodology resulting in [~]60 imaged lipids and [~]60 imaged metabolites at 20 {micro}m pixel size and subsequently spatial proteomics by LMD, detecting over 5,000 proteins from the same tissue. To demonstrate the capabilities of the workflow in preclinical context, we apply SIMO to a metastasizing melanoma PDX model, identifying over 100 spatially localized lipids and metabolites, and over 5,000 proteins across metastases and non-tumor tissues in liver. SIMO enables precise ROI selection, statistical comparison of protein regulation, and alignment of metabolic and lipidomics pathways across spatial omics and region-specific proteomics, demonstrating its value as a spatial multi-omics platform.

biochemistry↗

bioRxiv2025

Tumor Genotype Dictates Mitochondrial and Immune Vulnerabilities in Liver Cancer

Although oncogenic alterations influence tumor metabolism, how they impose distinct metabolic programs within a shared tissue context remains poorly defined. Here, we developed a rapid mitochondrial profiling platform to compare metabolites and proteins in genetic models of primary liver cancer (PLC). Analyses of six genetically distinct PLCs revealed that mitochondrial energy metabolism is largely dictated by oncogene identity. Kras-driven tumors required creatine metabolism to buffer energy demands during early tumorigenesis, whereas c-MYC-driven tumors relied on oxidative phosphorylation. Among c-MYC-driven PLCs, Pten-deficient tumors accumulated mitochondrial phosphoethanolamine, a precursor for phosphatidylethanolamine (PE) synthesis. Inhibition of PE synthesis selectively impaired the growth of Pten-deficient tumors and extended survival, in part through enhanced infiltration of CD8 T cells and sensitization to TNF-mediated cytotoxicity. Mechanistically, loss of PE elevated surface TNF receptor 2 (TNFR2), promoting TNF signaling and pro-inflammatory response. These findings uncover genotype-specific mitochondrial metabolic liabilities and establish PE synthesis as a tumor-intrinsic mechanism of immune evasion in PLC.

cancer biology↗

bioRxiv2024

Distinct DNA Methylation Signatures in Maternal Blood Reveal Unique Immune Cell Shifts in Preeclampsia and the Pregnancy-Postpartum Transition

1.0Preeclampsia (PE) is a hypertensive disorder of pregnancy characterized by immune dysregulation and significant risks to maternal and fetal health. While current management relies on high-risk patient monitoring and early diagnosis, these methods are costly and burdensome, especially for low-risk pregnancies. There is a pressing need for non-invasive tools to predict and monitor PE. DNA methylation (DNAm) is a type of DNA modification that influences gene expression, and has been associated with immune cell dynamics and PE pathogenesis. This study explores whether DNAm-based immune cell composition profiling can provide insights into PE-related immune dysregulation. We conducted a search in the Gene Expression Omnibus (GEO) for DNA methylation datasets using Illumina 27K, 450K, and EPIC arrays from maternal blood in both healthy and PE pregnancies. We found two studies that met our criteria, involving a total of 24 healthy pregnancies and 14 with PE. To estimate the composition of immune cells (including CD8T, CD4T, Monocytes, Natural Killer, Neutrophils, Eosinophils, and B cells) based on DNA methylation data, we employed the R package EpiDISH. We used a linear model to compare statistical differences in the proportions of immune cells between PE cases and the control group. Longitudinal trends were also examined to capture immune cell shifts from pregnancy to postpartum. We found that monocyte proportions were significantly reduced in preeclamptic pregnancies compared to normotensive pregnancies (p=0.013). No significant differences were observed in other immune cell types, including T cells, B cells, neutrophils, eosinophils, and natural killer cells. Longitudinal analyses revealed substantial immune cell shifts in the postpartum period, including increased monocytes, B cells, CD4+ T cells, and CD8+ T cells, emphasizing the importance of gestational age in immune dynamics. These findings support DNAm profiling as a valuable tool for understanding immune cell dynamics in PE. Reduced monocyte proportions in PE highlight the role of immune dysregulation in its pathogenesis. Longitudinal sampling provides additional insights into the evolution of immune changes throughout pregnancy and postpartum, offering potential for developing predictive and monitoring tools for PE. Future studies with larger, more diverse cohorts are essential to refine the utility of DNAm in pregnancy complications.

genomics↗

bioRxiv2024

Examining Sex-Specific DNA Methylation and Variability Post In Vitro Fertilization

Infertility impacts up to 17.5% of reproductive-aged couples worldwide. To aid in conception, many couples turn to assisted reproductive technology, such as in vitro fertilization (IVF). IVF can introduce both physical and environmental stressors that may alter DNA methylation regulation, an important and dynamic process during early fetal development. This meta-analysis aims to assess the differences in the placental DNA methylome between spontaneous and IVF pregnancies. We identified three studies from NCBI GEO that measured DNA methylation with an Illumina Infinium Microarray in post-delivery placental tissue from both IVF and spontaneous pregnancies with a total of 575 samples for analysis (n = 96 IVF, n = 479 spontaneous). While there were no significant or differentially methylated CpGs in mixed or female stratified populations, we identified 9 CpGs that reached statistical significance (FDR <0.05) between IVF (n = 56) and spontaneous (n = 238) placentae. 7 autosomal CpGs and 1 X chromosome CpG was hypermethylated and 2 autosomal CpGs were hypomethylated in the IVF placentae compared to spontaneous. Autosomal CpGs closest to LIPJ, EEF1A2, and FBRSL1 also met our criteria to be classified as biologically differentially methylated CpGs (FDR <0.05, |{Delta}{beta}|>0.05). When analyzing variability differences in {Delta}{beta} values between IVF females, IVF males, spontaneous females and spontaneous males, we found a significant shift to greater variability in the both IVF males and females compared to spontaneous (p <2.2e-16, p <2.2e-16). Trends of variability were further analyzed in the biologically differentially methylated autosomal CpGs near LIPJ EEF1A2, and FBRSL1, and while these regions were statistically significant in males, the female {Delta}{beta}s and {Delta}CoVs followed a similar trend that differed in magnitude. In males and females there was a statistically significant difference in proportions of endothelial cells, hofbauer cells, stromal cells and syncytiotrophoblasts between spontaneous and in vitro Fertilization (IVF) populations. We also observed significant differences between sex within reproduction type in syncytiotrophoblasts and trophoblasts. The results of this study are critical to further understand the impact of IVF on tissue epigenetics which may help to investigate the connections between IVF and negative pregnancy outcomes. Additionally, our study supports sex specific differences in placental DNA methylation and cell composition should be considered as factors for future placental DNA methylation analyses.

genomics↗