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.

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In the neuroendocrine system, corticotropin-releasing hormone (CRH) plays an important role in the hypothalamic–pituitary–adrenal/interrenal (HPA/HPI) axis. It exerts its effects by activating CRHRs, which belong to the class B G protein-coupled receptor family. Two characteristic genes of CRHR1 subtypes in the Larimichthys crocea genome were identified: LcCRHR1-1 and LcCRHR1-2. Alignments indicated that they were highly homologous to known and validated teleost CRHR1s. The CDS sequences of the two receptors were cloned into the pEGFP-N1 plasmid, and membrane localization of the fusion expressing LcCRHR1-1-EGFP and LcCRHR1-2-EGFP was revealed in HEK293 cells. Treatment with LcCRH could lead to two receptors internalization and trigger a significant increase in the secondary messenger cAMP and Ca2+ and mitogen-activated protein kinase phosphorylation in an LcCRH dose-dependent manner. Based on quantitative real-time PCR, LcCRHR1s were expressed in all examined tissues and highly expressed in the brain and ovaries. Furthermore, immunohistochemical findings showed the specific localization of CRHR1s in ovarian follicle cells. Collectively, our study identified two CRH receptors in L. crocea and suggested that the CRH/CRHR1 system is potentially involved in the neuroendocrine regulation of reproduction in this marine 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 ( Lc Mtnr1a1, Lc Mtnr1a2, Lc Mtnr1b1, Lc Mtnr1b2, and Lc Mtnr1c) were significantly activated by MT, triggering extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation through different G protein coupling signaling pathways, with exclusive G αi -dependency for Lc Mtnr1a2 and Lc Mtnr1c, and G αq -dependency for two Lc Mtnr1b paralogs, whereas Lc Mtnr1a1 activated G αi and G αs 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.

Combing the theory of role models (a figure other people look up to in order to help determine appropriate behaviors) and the theory of teens identity, an interesting correlation about the effect of social media is found to both of them. This paper have the speculation that role models help identity in teens. This paper focuses on the group of LGBTQ teenagers. The use of questionnaires and interviews helps to find out that the development of social media. Specifically, with the increase in LGBTQ role models, more teenagers are able to identify themselves about their own sexuality. Based on the data, it proves that most of the LGBTQ teenagers believe role models help them in a positive way. According to the evidence, the new generation is much opener and firmer in identifying themselves. Hence, this paper estimates that the improvement in teens self identity cannot leave the help of role models in social media. It is expected that the development of social media, more teenagers can be able to distinguish themselves and be accepted.