Search bioRxiv⌕ Search

Biology subjects

Alan, J.

Publications and source records attributed to Alan, J..

4 recordsLinked to original sources

A Robust Chemical-free Platform for Age-Synchronized Caenorhabditis elegans Populations Maintenance for High-Throughput Screening in Aging Studies

Caenorhabditis elegans (C. elegans) is a well-established model for investigating the mechanisms of aging and age-related disorders like neurodegeneration. However, maintaining age-synchronized populations of C. elegans for aging studies without genetic or pharmacological interventions presents significant challenges, given their high reproductive rate: each nematode produces over 300 progeny. The traditional method for maintaining an age-synchronized population for multi-day studies without interventions is labor-intensive and low-throughput, hindering research on aging mechanisms and the identification of novel interventions for aging. To address these limitations, a novel, robust method was developed to sustain age-synchronized populations in a 96-well plate liquid culture format for up to 12 days without custom-made apparatuses. The robustness of this method was substantially improved by optimizing the surface composition of the multi-well plate and disposables, refining culture parameters, including life stage, medium composition, and bacterial food concentration. To facilitate unbiased phenotype assessment throughout the lifespan, we used a Wmicrotracker ONE reader to monitor worm movement and viability in a multi-well plate. The overall fitness decline with aging using our method is comparable to that of worms maintained on solid agar. Lastly, using transgenic C. elegans carrying tauopathy, we demonstrated the ability of applying our optimized platform for high-throughput screening with a Z-factor of 0.7. Our novel method simplifies age-synchronized population maintenance, enhances progeny separation, and reduces costs, enabling high-throughput screening of compounds and RNAi libraries. These advancements greatly enhance the versatility of C. elegans as a model organism, offering a scalable platform for genetic and compound screening and for comprehensive investigations into drug discovery and disease mechanisms.

pharmacology and toxicology↗

Cytochrome P450 and Epoxide Hydrolase Metabolites in Aβ and tau-induced Neurodegeneration: Insights from Caenorhabditis elegans

This study aims to uncover potent cytochrome P450 (CYP) and epoxide hydrolase (EH) metabolites implicated in A{beta} and/or tau-induced neurodegeneration, independent of neuroinflammation, by utilizing Caenorhabditis elegans (C. elegans) as a model organism. Our research reveals that A{beta} and/or tau expression in C. elegans disrupts the oxylipin profile, and epoxide hydrolase inhibition alleviates the ensuing neurodegeneration, likely through elevating the epoxy-to-hydroxy ratio of various CYP-EH metabolites. In addition, our results indicated that the A{beta} and tau likely affect the CYP-EH metabolism of PUFA through different mechanism. These findings emphasize the intriguing relationship between lipid metabolites and neurodegenerations, in particular, those linked to A{beta} and/or tau aggregation. Furthermore, our investigation sheds light on the crucial and captivating role of CYP PUFA metabolites in C. elegans physiology, opening up possibilities for broader implications in mammalian and human contexts. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=92 SRC="FIGDIR/small/560527v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@8fd3fdorg.highwire.dtl.DTLVardef@a6c4e1org.highwire.dtl.DTLVardef@c7a5a7org.highwire.dtl.DTLVardef@14c8ce2_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

Dihydroxy-Metabolites of Dihomo-gamma-linolenic Acid Drive Ferroptosis- Mediated Neurodegeneration

Even after decades of research, the mechanism of neurodegeneration remains understudied, hindering the discovery of effective treatments for neurodegenerative diseases. Recent reports suggest that ferroptosis could be a novel therapeutic target for neurodegenerative diseases. While polyunsaturated fatty acid (PUFA) plays an important role in neurodegeneration and ferroptosis, how PUFAs may trigger these processes remains largely unknown. PUFA metabolites from cytochrome P450 and epoxide hydrolase metabolic pathways may modulate neurodegeneration. Here, we test the hypothesis that specific PUFAs regulate neurodegeneration through the action of their downstream metabolites by affecting ferroptosis. We find that the PUFA, dihomo gamma linolenic acid (DGLA), specifically induces ferroptosis-mediated neurodegeneration in dopaminergic neurons. Using synthetic chemical probes, targeted metabolomics, and genetic mutants, we show that DGLA triggers neurodegeneration upon conversion to dihydroxyeicosadienoic acid through the action of CYP-EH, representing a new class of lipid metabolite that induces neurodegeneration via ferroptosis.

neuroscience↗

The Atypical Rho GTPase CHW-1 Works With SAX-3/Robo to Mediate Axon Guidance in Caenorhabditis elegans

During development, neuronal cells extend an axon towards their target destination in response to a cue to form a properly functioning nervous system. Rho proteins, Ras-related small GTPases that regulate cytoskeletal organization and dynamics, cell adhesion, and motility, are known to regulate axon guidance. Despite extensive knowledge about canonical Rho proteins (RhoA/Rac1/Cdc42), little is known about the Caenorhabditis elegans (C. elegans) atypical Cdc42-like family members CHW-1 and CRP-1 in regards to axon pathfinding and neuronal migration. chw-1(Chp/Wrch) encodes a protein that resembles human Chp (Wrch-2/RhoV) and Wrch-1 (RhoU), and crp-1 encodes for a protein that resembles TC10 and TCL. Here, we show that chw-1 works redundantly with crp-1 and cdc-42 in axon guidance. Furthermore, proper levels of chw-1 expression and activity are required for proper axon guidance. When examining CHW-1 GTPase mutants, we found that the native CHW-1 protein is likely partially activated, and mutations at a conserved residue (position 12 using Ras numbering, position 18 in CHW-1) alter axon guidance and neural migration. Additionally, we showed that chw-1 genetically interacts with the guidance receptor sax-3 in PDE neurons. Finally, in VD/DD motor neurons, chw-1 works downstream of sax-3 to control axon guidance. In summary, this is the first study implicating the atypical Rho GTPases chw-1 and crp-1 in axon guidance. Furthermore, this is the first evidence of genetic interaction between chw-1 and the guidance receptor sax-3. These data suggest that chw-1 is likely acting downstream and/or in parallel to sax-3 in axon guidance.

developmental biology↗