Dataset Information

The acute transcriptome response of the midbrain/diencephalon to injury in the adult mummichog (Fundulus heteroclitus).

ABSTRACT: Adult fish produce new cells throughout their central nervous system during the course of their lives and maintain a tremendous capacity to repair damaged neural tissue. Much of the focus on understanding brain repair and regeneration in adult fish has been directed at regions of the brainstem and forebrain; however, the mesencephalon (midbrain) and diencephalon have received little attention. We sought to examine differential gene expression in the midbrain/diencephalon in response to injury in the adult fish using RNA-seq. Using the mummichog (Fundulus heteroclitus), we administered a mechanical lesion to the midbrain/diencephalon and examined differentially expressed genes (DEGs) at an acute recovery time of 1 h post-injury. Comparisons of whole transcriptomes derived from isolated RNA of intact and injured midbrain/diencephalic tissue identified 404 DEGs with the vast majority being upregulated. Using qPCR, we validated the upregulation of DEGs pim-2-like, syndecan-4-like, and cd83. Based on genes both familiar and novel regarding the adult brain response to injury, these data provide an extensive molecular profile giving insight into a range of cellular processes involved in the injury response of a brain regenerative-capable vertebrate.

SUBMITTER: Bisese EC

PROVIDER: S-EPMC6937918 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:The objective of this study was to gain mechanistic insight into how mummichog are able to produce eggs during exposures to high levels of EE2. Mummichog were exposed to 0, 50 or 250 ng/L of EE2 for 14 d. A mummichog microarray was used to identify genomic responses associated with high EE2 exposure, and effects of EE2 on target genes involved in lipid mobilization and transport and steroidogenesis, two important (EE2 regulated) pathways involved in egg production, were measured using real-time PCR. In addition, changes at higher level biological endpoints such as plasma steroid production and gonad morphology were measured to examine downstream responses to EE2. There were no differences in gonadosomatic index, liversomatic index, gonad development, or plasma estradiol levels after exposure to EE2, although testosterone decreased with EE2 exposures. Similar to other species, mummichog showed alterations to plasma steroid levels, and similar processes at the molecular level were identified as being altered by EE2, including cell processes associated with lipids. However, unlike other species, mummichog showed no differences in GSI or ovarian development. Fatty acids were affected at both the transcript and translation level, which suggests they are a major target of estrogens. Lipids are important for both growth and reproduction, and provide oocytes with nutrients. Interestingly, mummichog showed no effect on apolipoprotein expression, which is important in lipid transport. Therefore, it is hypothesized that mummichog are normally able to transport lipids for energy and nutrients to the ovary, while this is affected in other species. Novel gene regulatory networks for protein modification targets were also constructed to learn more about the potential roles of estrogens in the teleost liver. Although post-translational modifications (PTMs) are important regulatory mechanisms, the roles of PTMs in protein regulation in fish and the susceptibility of PTMs to aquatic pollutants are largely unexplored and may offer novel insight into mechanisms of endocrine disruption.

Project description:The Atlantic killifish (Fundulus heteroclitus) is an environmental sentinel organism used extensively for studies on environmental toxicants and salt (NaCl) homeostasis. Previous research in our laboratory has shown that rapid acclimation of killifish to seawater is mediated by trafficking of CFTR chloride channels from intracellular vesicles to the plasma membrane in the opercular membrane within the first hour in seawater, which enhances chloride secretion into seawater, thereby contributing to salt homeostasis. Acute transition to seawater is also marked by an increase in both mRNA and protein levels of serum glucocorticoid kinase 1 (SGK1) within 15 minutes of transfer. Although the rise in SGK1 in gill and its functional analog, the opercular membrane, after seawater transfer precedes the increase in membrane CFTR, a direct role of SGK1 in elevating membrane CFTR has not been established in vivo. To test the hypothesis that SGK1 mediates the increase in plasma membrane CFTR we designed two functionally different vivo-morpholinos to knock down SGK1 in gill, and developed and validated a vivo-morpholino knock down technique for adult killifish. Injection (intraperitoneal, IP) of the splice blocking SGK1 vivo-morpholino reduced SGK1 mRNA in the gill after transition from fresh to seawater by 66%. The IP injection of the translational blocking and splice blocking vivo-morpholinos reduced gill SGK1 protein abundance in fish transferred from fresh to seawater by 64% and 53%, respectively. Moreover, knock down of SGK1 completely eliminated the seawater induced rise in plasma membrane CFTR, demonstrating that the increase in SGK1 protein is required for the trafficking of CFTR from intracellular vesicles in mitochondrion rich cells to the plasma membrane in the gill during acclimation to seawater. This is the first report of the use of vivo-morpholinos in adult killifish and demonstrates that vivo-morpholinos are a valuable genetic tool for this environmentally relevant model organism.

Project description:To better assess the impact of contaminants on fish reproduction, it is increasingly important to collect data at multiple levels of biological organization. However, a challenge in ecotoxicology is that three of the most commonly measured reproductive endpoints; gonad histology, ex vivo steroid production, and gene expression, can be difficult to obtain in small-bodied fish (e.g. zebrafish, Japanese medaka, fathead minnow) due to limited tissue availability. Using 5α-dihydrotestosterone (DHT) as a test compound, the objectives of the current study were to assess the feasibility of measuring gene expression in tissues also used for ex vivo steroid production studies. A portion of the testes was also used for qualitative histological examination. Male mummichog were exposed to 0, 5, and 50 µg/L DHT for 21 days. Following the exposure, testes were collected and separated into three pieces for histology, ex vivo incubation to measure steroidogenic capacity [Testosterone(T), 17β-estradiol (E2), 11-ketotestosterone (11KT)] and gene expression analyses. Testis RNA at time of dissection and testis RNA at end of ex vivo incubation (18 h) was collected and assessed for RNA integrity. The expression of genes coding for estrogen receptor βa (esrba) and estrogen receptor βb (esrbb) as well as the key steroidogenic genes, steroidogenic acute regulatory protein (star), P450 side chain cleavage (p450scc) and 11β-hydroxysteroid dehydrogenase (hsd11b3) were assessed in testis before and after ex vivo incubation. There were no significant differences in RNA quality between the two time points, however the expression of esrba, esrbb and p450scc was significantly lower post-incubation, although star, hsd11b3, and all four reference gene expression levels remained unchanged over time. DHT did not affect the expression of any of the measured genes at either concentration. Histological examination showed that all fish contained mature testes dominated by spermatozoa and spermatids. DHT did not affect T production but significantly decreased 11KT production in the high treatment group. This suggests a role for DHT in androgen regulation, and has

Dataset Information

The acute transcriptome response of the midbrain/diencephalon to injury in the adult mummichog (Fundulus heteroclitus).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets