Project description:SEIPIN, an evolutionary conserved protein, plays pivotal roles during lipid droplet (LD) biogenesis and is associated with various human diseases with unclear mechanisms. Here, we analyzed C. elegans mutants deleted of the sole SEIPIN gene, seip-1. Homozygous seip-1 mutants displayed penetrant embryonic lethality, which is caused by the disruption of the lipid-rich permeability barrier, the innermost layer of the C. elegans embryonic eggshell. In C. elegans oocytes and embryos, SEIP-1 is associated with LDs and crucial for controlling LD size and lipid homeostasis. The seip-1 deletion mutants reduced the ratio of polyunsaturated fatty acids (PUFAs) in their embryonic fatty acid pool. Interestingly, dietary supplementation of selected n-6 PUFAs rescued the embryonic lethality and defective permeability barrier. Accordingly, we propose that SEIP-1 may maternally regulate LD biogenesis and lipid homeostasis to orchestrate the formation of the permeability barrier for eggshell synthesis during embryogenesis. A lipodystrophy allele of seip-1 resulted in embryonic lethality as well and could be rescued by PUFA supplementation. These experiments support a great potential for using C. elegans to model seipin-associated human diseases.
Project description:Seipin, an evolutionary conserved protein, plays pivotal roles during lipid droplet (LD) biogenesis and is associated with various human diseases with unclear mechanisms. Here, we analyzed Caenorhabditis elegans mutants deleted of the sole SEIPIN gene, seip-1 Homozygous seip-1 mutants displayed penetrant embryonic lethality, which is caused by the disruption of the lipid-rich permeability barrier, the innermost layer of the C. elegans embryonic eggshell. In C. elegans oocytes and embryos, SEIP-1 is associated with LDs and is crucial for controlling LD size and lipid homeostasis. The seip-1 deletion mutants reduced the ratio of polyunsaturated fatty acids (PUFAs) in their embryonic fatty acid pool. Interestingly, dietary supplementation of selected n-6 PUFAs rescued the embryonic lethality and defective permeability barrier. Accordingly, we propose that SEIP-1 may maternally regulate LD biogenesis and lipid homeostasis to orchestrate the formation of the permeability barrier for eggshell synthesis during embryogenesis. A lipodystrophy allele of seip-1 resulted in embryonic lethality as well and could be rescued by PUFA supplementation. These experiments support a great potential for using C. elegans to model SEIPIN-associated human diseases.
Project description:The egg production cycle of broiler breeder hens is comparatively shorter than laying hens, and as they age, their egg production and eggshell quality decline. The eggshell formation occurs in the shell glands, which are influenced by several factors, including aging. The objectives of the study were to 1) identify differentially expressed genes (DEGs) and biological pathways in the shell glands (young vs aged) and 2) determine the age-associated changes in eggshell quality. The shell glands tissues were collected from broiler breeder hens at peak-lay (35 weeks of age; termed as “young”) and late-lay phases (50 weeks of age; termed as “aged”) (n=30/group) at 10-15 hours post-ovulation (unclassified egg present in the shell glands). To delineate the genes and biological pathways associated with eggshell biomineralization, total RNAs extracted from the shell glands of young and aged hens (n=6/group) were analyzed using RNA sequencing and validated using real-time PCR. The ultrastructure quality of eggshells (n=10 eggs/group) was analyzed using a Scanning Electron Microscope (SEM), and the elemental composition of eggshells was measured using SEM-Energy Dispersive Spectrometry, and their variability was confirmed by t-test in RStudio. Eggshell strength, thickness, palisade layer, and mammillary width were significantly higher in the young, while mammillary knobs were wider in aged hens (p<0.05). The sulfur and potassium levels in eggshells were higher in young hens than aged ones. Although the young group had a higher calcium concentration in the eggshells, the difference was statistically insignificant (p>0.05). RNA-Seq data identified highly upregulated genes specific to eggshell biomineralization, such as SPP1 (binds to hydroxyapatite), OTOP2 (maintains high conc. of cytosolic Ca2+), PKD2 (helps in releasing Ca2+), SLC22A15 (transports organic ions), and STAB2 (binds to gram-positive and gram-negative bacteria). The DEGs showed significant enrichment for biological pathways (SLC6A6, KCNK7, UCP3, SCNN1A, PKD2, OTOP2) associated with the transport of monoatomic and inorganic cations across the cell membrane, molecular functions related to the transport of potassium ions and the activity of monoatomic cation channels (KCNK7, PKD2, OTOP2), and the cellular components involved in the luminal side of the endoplasmic reticulum membrane (CALR, PKD2). These findings suggest that the aging process downregulates the transcriptomes of the shell glands, negatively impacting the transportation of ions required for eggshell formation, resulting in poor eggshell quality.
Project description:This project focuses on the proteomic analysis of Xitou eggshell samples using high-resolution LC-MS/MS. The primary goal is to identify and characterize the protein components, evaluate their post-translational modifications, and compare them with modern goose eggshell proteomes. The results aim to provide insights into the biomineralization mechanisms and evolutionary differences in avian eggshell formation.
Project description:We used a transcriptomic approach based on the comparison of the expression in the uterine tissue when an hard-shelled egg was in calcification (normal) versus uterine tissue collected after premature expulsion of the egg before mineralization has begun (expelled) to better appreciate which uterine chicken proteins are associated with the supply of minerals and potentially actives on the biomineralisation process during eggshell formation.