Biology subjects

Lempradl, A.

Publications and source records attributed to Lempradl, A..

9 recordsLinked to original sources

bioRxiv2026

A Drosophila screen identifies domino as a link between chromatin regulation and synaptic organization

While heterozygous gene-disrupting variants in dosage-sensitive genes are strongly implicated in autism spectrum disorder (ASD), their effects on behavior in vivo remain poorly understood. To address this, we conducted a targeted behavioral screen in Drosophila using high-confidence ASD risk genes. This screen identified 48 lines with altered sleep, activity, or social behavior, including many genes not previously known to regulate these behaviors. The chromatin remodeler domino (dom) emerged as a compelling hit. Heterozygous mutants showed altered social spacing and male-biased changes in sleep and activity. RNA-sequencing revealed changes in gene expression and splicing associated with synaptic pathways. Consistent with these molecular changes, immunofluorescence revealed increased presynaptic activity in a brain region associated with sleep and sensory processing. Together, these findings show that partial loss of ASD risk genes is sufficient to alter behavior and identify dom as a link between transcriptional regulation, synaptic organization and behavior.

neuroscience↗

bioRxiv2025

Mutation of the white gene in Drosophila has broad phenotypic and transcriptomic effects

The white (w) gene, one of the most widely used genetic markers in Drosophila research, serves as a standard background mutation for transgene insertions and genetic manipulations1. While its primary function involves eye pigmentation, mutations in white have been associated with diverse phenotypic effects, including those related to metabolism, behavior, and stress responses2-19. However, many studies using these mutants do not account for differences in genetic background, raising concerns about the interpretation of experimental results. To ensure that the observed phenotypic differences are attributable to white itself, rather than other genetic differences due to background, we established isogenic fly strains through backcrossing that differ only by the presence or absence of the white gene. Given the likely metabolic consequences of white gene deletion and its crucial role in neurotransmitter production, we focused our phenotyping assays on behavioral, metabolic, and fitness-related outcomes and performed transcriptomic analysis on adult fly heads. Our findings reveal widespread changes in adult brain gene expression and behavioral, metabolic, and fitness traits, demonstrating that loss of white influences multiple biological processes beyond its established role in eye pigmentation. These results emphasize the necessity of genetic background control in Drosophila research and warrant caution when using white mutants as a baseline for comparative studies.

genetics↗

bioRxiv2024

Integrative multiomics analysis of metabolic dysregulation induced by occupational benzene exposure in mice

Background: Type 2 Diabetes Mellitus (T2DM) is a significant public health burden. Emerging evidence links volatile organic compounds (VOCs), such as benzene to endocrine disruption and metabolic dysfunction. However, the effects of chronic environmentally relevant VOC exposures on metabolic health are still emerging. Objective: Building on our previous findings that benzene exposure at smoking levels (50 ppm) induces metabolic impairments in male mice, we investigated the effects of occupationally relevant, below OSHA approved, benzene exposure on metabolic health. Methods: Adult male C57BL/6 mice were exposed to 0.9ppm benzene 8 hours a day for 9 weeks. We assessed measures of metabolic homeostasis and conducted RNA and proteome sequencing on insulin-sensitive organs (liver, skeletal muscle, adipose tissue). Results: This low-dose exposure caused significant metabolic disruptions, including hyperglycemia, hyperinsulinemia, and insulin resistance. Transcriptomic analysis of liver, skeletal muscle, and adipose tissue identified key changes in metabolic and immune pathways especially in liver. Proteomic analysis of the liver revealed mitochondrial dysfunction as a shared feature, with disruptions in oxidative phosphorylation, mitophagy, and immune activation. Comparative analysis with high-dose (50 ppm) exposure showed both conserved and dose-specific transcriptomic changes in liver, particularly in metabolic and immune responses. Conclusions: Our study is the first to comprehensively assess the impacts of occupational benzene exposure on metabolic health, highlighting mitochondrial dysfunction as a central mechanism and the dose-dependent molecular pathways in insulin-sensitive organs driving benzene-induced metabolic imbalance. Our data indicate that current OSHA occupational exposure limits for benzene are insufficient, as they could result in adverse metabolic health in exposed workers, particularly men, following chronic exposure.

pharmacology and toxicology↗

bioRxiv2024

Single-embryo metabolomics reveals developmental metabolism in the early Drosophila embryo

Early embryonic development is characterized by the transition from maternal factor reliance to zygotic control. These processes set the stage for the embryos basic structure and cellular differentiation. While relatively detailed knowledge exists of the transcriptional events during early development, little is known about the concurrent metabolic processes. Understanding these processes, however, is important since they are linked to cell fate determination and organ and tissue formation. The primary reasons for the limited progress in the field are technical limitations due to the small amount of material available during early embryonic time windows. Here, we introduce a novel single-embryo methodology that places us in an exciting position to analyze the early embryos metabolome and transcriptome in an integrated manner and at high temporal resolution. The resulting data allow us to map concomitant metabolic and transcriptional programs in early Drosophila embryonic development. Our results reveal that a substantial number of metabolites exhibit dynamic patterns with some changing even before the onset of zygotic transcription. dNTPs for example show a temporal pattern that correlates with cell division patterns in the early embryo. In summary, here we present an operationally simple single-embryo metabolomics methodology and provide a detailed picture of early developmental metabolic processes at unprecedented temporal resolution.

developmental biology↗

bioRxiv2023

Prenatal benzene exposure alters offspring hypothalamic development predisposing to metabolic disease in later life

The hypothalamus is essential in the regulation of metabolism, notably during critical windows of development. An abnormal hormonal and inflammatory milieu during development can trigger persistent changes in the function of hypothalamic circuits, leading to long-lasting effects on the bodys energy homeostasis and metabolism. We recently demonstrated that gestational exposure to benzene at smoking levels induces severe metabolic dysregulation in the offspring. Given the central role of the hypothalamus in metabolic control, we hypothesized that prenatal exposure to benzene impacts hypothalamic development, contributing to the adverse metabolic effects in the offspring. C57BL/6JB dams were exposed to benzene in the inhalation chambers exclusively during pregnancy (from E0.5 to E19). The transcriptome analysis of the offspring hypothalamus at postnatal day 21 (P21) revealed changes in genes related to metabolic regulation, inflammation, and neurodevelopment exclusively in benzene-exposed male offspring. Moreover, the hypothalamus of prenatally benzene-exposed male offspring displayed alterations in orexigenic and anorexigenic projections, impairments in leptin signaling, and increased microgliosis. Additional exposure to benzene during lactation did not promote further microgliosis or astrogliosis in the offspring, while the high-fat diet (HFD) challenge in adulthood exacerbated glucose metabolism and hypothalamic inflammation in benzene-exposed offspring of both sexes. These findings reveal the persistent impact of prenatal benzene exposure on hypothalamic circuits and neuroinflammation, predisposing the offspring to long-lasting metabolic health conditions.

neuroscience↗

bioRxiv2022

Continuous transcriptome analysis reveals novel patterns of early gene expression in Drosophila embryos.

Early organismal development consists of transformative events that lay the foundation for body formation and long-term phenotype. Despite this understanding, the rapid progression of events and the limited material available are major barriers to studying the earliest stages. The size and accessibility of Drosophila embryos overcome some of these limitations, and several studies characterizing early transcriptional events have been reported. Unfortunately, manual embryo staging, and elaborate protocols make the techniques employed in these studies prone to human and technical errors and incompatible with routine laboratory use. Herein, we present a straight-forward and operationally simple methodology for studying the early transcription ([≤]3 hours) in Drosophila. This method relies on single-embryo RNA-sequencing and transcriptome ordering along a developmental trajectory (pseudo-time), thereby avoiding the need for the staging of the embryos. The obtained high-resolution and time-sensitive mRNA expression profiles uncovered the exact onset of transcription and degradation of transcripts and revealed an earlier transcription start for several zygotic genes. In addition, degradation patterns suggest that maternal mRNA decay is independent of mRNA levels. By classifying each embryo as male or female, we were also able to study sex-biased transcription between the beginning of zygotic transcription to gastrulation and identified 120 differentially expressed mRNAs. Using sex-specific transcription signatures, embryos can be sexed directly, eliminating the need for Y-chromosome genotyping. Herein, we report an accessible, single-embryo sequencing approach for high-resolution, time-sensitive transcriptome analysis. Our data provide an unparalleled resolution of gene expression during early development and enhance the current understanding of early transcriptional processes.

genomics↗

bioRxiv2021

Intergenerational metabolic priming by sperm piRNAs

SummaryPreconception parental environment can reproducibly program offspring phenotype without altering the DNA sequence, yet the mechanisms underpinning this epigenetic inheritance remains elusive. Here, we demonstrate the existence of an intact piRNA-pathway in mature Drosophila sperm and show that pathway modulation alters offspring gene transcription in a sequence-specific manner. We map a dynamic small RNA content in developing sperm and find that the mature sperm carry a highly distinct small RNA cargo. By biochemical pulldown, we identify a small RNA subset bound directly to piwi protein. And, we show that piRNA-pathway controlled sperm small RNAs are linked to target gene repression in offspring. Critically, we find that full piRNA-pathway dosage is necessary for the intergenerational metabolic and transcriptional reprogramming events triggered by high paternal dietary sugar. These data provide a direct link between regulation of endogenous mature sperm small RNAs and transcriptional programming of complementary sequences in offspring. Thus, we identify a novel mediator of paternal intergenerational epigenetic inheritance.

developmental biology↗

bioRxiv2018

PROTEIN-CODING VARIANTS IMPLICATE NOVEL GENES RELATED TO LIPID HOMEOSTASIS CONTRIBUTING TO BODY FAT DISTRIBUTION

Body fat distribution is a heritable risk factor for a range of adverse health consequences, including hyperlipidemia and type 2 diabetes. To identify protein-coding variants associated with body fat distribution, assessed by waist-to-hip ratio adjusted for body mass index, we analyzed 228,985 predicted coding and splice site variants available on exome arrays in up to 344,369 individuals from five major ancestries for discovery and 132,177 independent European-ancestry individuals for validation. We identified 15 common (minor allele frequency, MAF[≥]5%) and 9 low frequency or rare (MAF<5%) coding variants that have not been reported previously. Pathway/gene set enrichment analyses of all associated variants highlight lipid particle, adiponectin level, abnormal white adipose tissue physiology, and bone development and morphology as processes affecting fat distribution and body shape. Furthermore, the cross-trait associations and the analyses of variant and gene function highlight a strong connection to lipids, cardiovascular traits, and type 2 diabetes. In functional follow-up analyses, specifically in Drosophila RNAi-knockdown crosses, we observed a significant increase in the total body triglyceride levels for two genes (DNAH10 and PLXND1). By examining variants often poorly tagged or entirely missed by genome-wide association studies, we implicate novel genes in fat distribution, stressing the importance of interrogating low-frequency and protein-coding variants.

genetics↗

bioRxiv2017

The Polycomb-dependent epigenome controls β-cell dysfunction, dedifferentiation and diabetes

Chromatin is the physical template that stabilizes and specifies transcriptional programs. To date, it remains largely unclear to what extent chromatin machinery contributes to the susceptibility and progression of complex diseases. Here, we combined deep epigenome mapping with single cell transcriptomics to mine for evidence of chromatin dysregulation in type-2 diabetes. We identify two chromatin-state signatures that track the trajectory of {beta}-cell dysfunction in mice and humans: ectopic activation of bivalent Polycomb-domains and a loss of expression at a subclass of highly active domains containing key lineage-defining genes. {beta}-cell specific deletion of Polycomb (Eed/PRC2) triggers parallel transcriptional signatures. Intriguingly, these {beta}-cell Eed-knockouts also exhibit highly penetrant hyperglycemia-independent dedifferentiation indicating that Polycomb dysregulation sensitizes the {beta}-cell for dedifferentiation. These findings provide novel resources for exploring transcriptional and epigenetic control of {beta}-cell (dys)function. They identify PRC2 as necessary for long-term maintenance of {beta}-cell identity. The data suggest a two-hit model for loss of {beta}-cell identity in diabetes and highlight epigenetic therapeutic potential to block dedifferentiation.

genomics↗