Circadian patterns and photoperiodic modulation of clock gene expression and neuroendocrine hormone secretion in the marine teleost Larimichthys crocea.

The light/dark cycle, known as the photoperiod, plays a crucial role in influencing various physiological activities in fish, such as growth, feeding and reproduction. However, the underlying mechanisms of this influence are not fully understood. This study focuses on exploring the impact of different light regimes (LD: 12 h of light and 12 h of darkness; LL: 24 h of light and 0 h of darkness; DD: 0 h of light and 24 h of darkness) on the expression of clock genes (LcClocka, LcClockb, LcBmal, LcPer1, LcPer2) and the secretion of hormones (melatonin, GnRH, NPY) in the large yellow croaker, Larimichthys crocea. Real-time quantitative PCR (RT-qPCR) and enzyme-linked immunosorbent assays were utilized to assess how photoperiod variations affect clock gene expression and hormone secretion. The results indicate that changes in photoperiod can disrupt the rhythmic patterns of clock genes, leading to phase shifts and decreased expression. Particularly under LL conditions, the pineal LcClocka, LcBmal and LcPer1 genes lose their rhythmicity, while LcClockb and LcPer2 genes exhibit phase shifts, highlighting the importance of dark phase entrainment for maintaining rhythmicity. Additionally, altered photoperiod affects the neuroendocrine system of L. crocea. In comparison to the LD condition, LL and DD treatments showed a phase delay of GnRH secretion and an acceleration of NPY synthesis. These findings provide valuable insights into the regulatory patterns of circadian rhythms in fish and may contribute to optimizing the light environment in the L. crocea farming industry.

Comparative transcriptome analysis reveals key genes and pathways related to gonad development in the sea cucumber Apostichopus japonicus.

The sea cucumber Apostichopus japonicus is an economically important marine species in China, and understanding the mechanisms underlying its gonad development is crucial for successful reproduction and breeding. In this study, we performed transcriptome comparisons and analyses of A. japonicus gonadal and non-gonadal tissues to identify genes and molecular pathways associated with gonadal development. We also supplemented the annotation of the A. japonicus genome. Collectively, results revealed a total of 941 ovary-specific genes and 2499 testis-specific genes through different expression analysis and WGCNA analysis. The most enriched pathways in ovary and testis were "DNA replication" and "purine metabolism", respectively. Additionally, we identified key candidate gene modules that control gonad development and germ cell maturation, with CDT1 and DYNC2LI1 serving as hub genes. Our findings provide important insights into the gonadal development system of A. japonicus and offer valuable references for further research on reproductive biology in this marine invertebrate species.

Melatonin modulates the hypothalamic-pituitary neuroendocrine axis to regulate physiological color change in teleost fish.

Melatonin (MT) is a crucial neuroendocrine regulator of various physiological activities in vertebrates, especially in circadian or seasonal rhythm control. In the present study, the large yellow croaker (Larimichthys crocea), a marine bony fish with circadian body color change behavior, is chosen for functional investigation on teleost MT signaling systems that remain uncharacterized. All five melatonin receptors (LcMtnr1a1, LcMtnr1a2, LcMtnr1b1, LcMtnr1b2, and LcMtnr1c) were significantly activated by MT, triggering extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation through different G protein coupling signaling pathways, with exclusive Gαi-dependency for LcMtnr1a2 and LcMtnr1c, and Gαq-dependency for two LcMtnr1b paralogs, whereas LcMtnr1a1 activated Gαi and Gαs dual-dependent signaling pathways. A comprehensive model of the MT signaling system in the hypothalamic-pituitary neuroendocrine axis was further constructed based on ligand-receptor interaction analysis using single-cell RNA-seq data, as well as spatial expression patterns of Mtnrs and related neuropeptides in central neuroendocrine tissues. A novel regulatory pathway of MT/melanin-concentrating hormone (MCH) and MT/(tachykinin precursor 1 (TAC1)+corticotropin-releasing hormone (CRH))/melanocyte-stimulating hormone (MSH) was discovered that functions in chromatophore mobilization and physiological color change and was further validated by pharmacological experiments. Together, our findings define multiple intracellular signaling pathways mediated by L. crocea melatonin receptors and provide the first in-depth evidence that uncover the upstream modulating roles of the MT signaling system in the hypothalamic-pituitary neuroendocrine axis of a marine teleost species, particularly in chromatophore mobilization and physiological color change.

Bisphenol A (BPA) Directly Activates the G Protein-Coupled Estrogen Receptor 1 and Triggers the Metabolic Disruption in the Gonadal Tissue of Apostichopus japonicus.

The sea cucumber, Apostichopus japonicus, is a marine benthic organism that feeds on small benthic particulate matter and is easily affected by pollutants. Bisphenol A (BPA, 4,4'-isopropylidenediphenol) has been identified as an endocrine disruptor. It is ubiquitously detectable in oceans and affects a variety of marine animals. It functions as an estrogen analog and typically causes reproductive toxicity by interfering with the endocrine system. To comparatively analyze the reproductive effects of estradiol (E2) and BPA on sea cucumbers, we identified a G protein-coupled estrogen receptor 1 (GPER1) in A. japonicus and investigated its effects on reproduction. The results showed that BPA and E2 exposure activated A. japonicus AjGPER1, thereby mediating the mitogen-activated protein kinase signaling pathways. High-level expression of AjGPER1 in the ovarian tissue was confirmed by qPCR. Furthermore, metabolic changes were induced by 100 nM (22.83 µg/L) BPA exposure in the ovarian tissue, leading to a notable increase in the activities of trehalase and phosphofructokinase. Overall, our findings suggest that AjGPER1 is directly activated by BPA and affects sea cucumber reproduction by disrupting ovarian tissue metabolism, suggesting that marine pollutants pose a threat to the conservation of sea cucumber resources.

Exploring Prognostic Signatures of Hepatocellular Carcinoma and the Potential Implications in Tumor Immune Microenvironment.

OBJECTIVE: The objective of this study is to construct a prognostic model using genetic markers of liver cancer and explore the signature genes associated with the tumor immune microenvironment. METHODS: Cox proportional hazards regression analysis was carried out to screen the significant HR using the dataset of TCGA Liver Cancer (LIHC) gene expression data. Then LASSO (least absolute shrinkage and selection operator) was performed to select the minimal variables with significant HR of genes. Thus, the prognostic model was constructed by the minimal variables with their HR. Time-dependent receiver-operating characteristic (ROC) curve and area under the ROC curve (AUC) value was used to assess the prognostic performance. Then the patients were divided into high and low-risk groups by the median of the model. Survival analysis was performed on the two groups with testing and an independent dataset. Furthermore, enrichment analysis of signature mRNAs and lncRNAs and their co-expression genes was performed. Then, Spearman rank correlation was used to calculate the correlation between immune cells and genes in the prognostic model, and abundance difference of the immune cells in high and low risks groups was tested. RESULTS: A total of 5989 genes with significant HR were identified. 6 key genes (three mRNAs: DHX37, SMIM7, and MFSD1, three lncRNAs: PIWIL4, KCNE5, and LOC100128398) screened by LASSO were used to construct the model with their HR value respectively. The AUC values of 1 and 5-year overall survival were 0.78 and 0.76 in discovery data and 0.67 and 0.68 in testing data. Survival analysis performed significantly discriminated high and low groups with testing and independent data. Furthermore, many immune cells such as nTreg found a significant correlation with the genes in the prognostic model, and many immune cells showed significantly different abundance in high and low-risk groups. CONCLUSION: In the study, we used Univariate Cox analyses and LASSO algorithm with TCGA gene expression data to construct the prognostic model in liver cancer patients. The prognostic model comprised of three mRNAs, including DHX37, SMIM7, MFSD1, and three lncRNAs, including PIWIL4, KCNE5, and LOC100128398. Furthermore, these gene expression levels were associated with the abundance of some immune cells, such as nTreg. Also, many immune cells have significantly different abundance in high and low-risk groups. All these results indicated that the combination with all these six genes could be the potential biomarker for the prognosis of liver cancer.

Pharmacological characterization and biological function of the interleukin-8 receptor, CXCR2, in largemouth bass (Micropterus salmoides).

Interleukin-8 (IL-8 or C-X-C motif chemokine ligand 8, CXCL8) is a cytokine secreted by numerous cell types and is best known for its functional roles in inflammatory response by binding to specific receptors (the interleukin-8 receptors, IL-8Rs). From the transcriptomic data of largemouth bass (Micropterus salmoides), we identified an IL-8R that is highly homologous to the functionally validated teleost IL-8Rs. The M. salmoides IL-8 receptor (MsCXCR2) was further compared with the C-X-C motif chemokine receptor 2 subfamily by phylogenetic analysis. Briefly, the full-length CDS sequence of MsCXCR2 was cloned into the pEGFP-N1 plasmid, and the membrane localization of fusion expressing MsCXCR2-EGFP was revealed in HEK293 cells. To determine the functional interaction between IL-8 and MsCXCR2, secretory expressed Larimichthys crocea IL-8 (LcIL-8) was used to stimulate MsCXCR2 expressing cells. MsCXCR2 was demonstrated to be activated by LcIL-8, leading to receptor internalization, which was further revealed by the detection of extracellular regulated protein kinase (ERK) phosphorylation. Quantitative real-time PCR was used to evaluate the expressional distribution and variation of MsCXCR2 in healthy and Nocardia seriolae infected fish. Based on our findings, MsCXCR2 was constitutively expressed in all examined tissues, despite at different levels. Furthermore, gene expression was found to be significantly upregulated in the liver and head kidney of diseased fish. Collectively, our findings reveal the molecular activity of MsCXCR2 and indicate the functional involvement of this IL-8R in the immune response induced by N. seriolae in M. salmoides.

Decreased miR-124-3p promoted breast cancer proliferation and metastasis by targeting MGAT5.

Non-coding RNAs (ncRNAs) have been shown to regulate gene expression involved in tumor progression of multiple malignancies. Numerous studies have indicated that N-acetylglucosaminyltransferase V (MGAT5), is an important tumorigenesis and metastasis-associated enzyme in breast cancer (BC). But, the underlying molecular mechanisms by which ncRNAs modulate MGAT5 expression in BC remain undetermined. In this study, we demonstrated that miR-124 expression at a low level in BC tissue was associated with poor prognosis of BC patients. Meanwhile, miR-124 reduced BC cell proliferation and metastasis. MGAT5 was confirmed as a direct target of miR-124. MGAT5 restoration attenuated the inhibitory effects of miR-124 on BC proliferation and metastasis in vitro and vivo. Overall, we provide new insight into the mechanisms by which miR-124 inhibits BC progression, suggesting the potential of miR-124 and MGAT5 as biomarkers for early diagnosis of breast cancer to provide innovative ideas and methods for the diagnosis and treatment of BC.

[Determination of main degradation products of lignin using reversed-phase high performance liquid chromatography].

An analytical method using reversed-phase high performance liquid chromatography (RP-HPLC) was developed for the separation and quantitative determination of main degradation products of lignin (4-hydroxybenzoic acid, vanillic acid, syringic acid, 4-hydroxybenzaldehyde, vanillin and syringaldehyde) during the steam exploded pretreatment for corn stovers. The separation was carried out on a C18 column with the mobile phase of acetonitrile-water (containing 1.5% acetic acid) at 30 degrees C at a flow rate of 0.8 mL/min and the detection wavelengths of 254 and 280 nm. Under the optimized conditions, the correlation coefficients of the 6 compounds were between 0.999 9 and 1.000 0. The recoveries of the 6 compounds were all above 96% and the relative standard deviations (n = 6) were less than 2.5%. This method is suitable for the determination of the main degradation products of lignin during the steam exploded pretreatment of lignocellulosics.