The Bromodomain testis-specific gene (Brdt) characterization and expression in gilthead seabream, Sparus aurata, and European seabass, Dicentrarchus labrax

Synthesis, SAR, and application of JQ1 analogs as PROTACs for cancer therapy

JQ1 is a wonder therapeutic molecule that selectively inhibits the BRD4 signaling pathway and is thus widely used in the anticancer drug discovery program. Due to its unique selective BRD4 binding property, its applications are further extended in the design and synthesis of bi-functional PROTAC molecules. This BRD4 targeting PROTAC molecule selectively degrades the protein by proteolysis. There are several modifications of JQ1 known to date and extensively explored for their applications in PROTAC technology by several research groups in academia as well as industry for targeting oncogenic genes. In this review, we have covered the discovery and synthesis of the JQ1 molecule. The SAR of the JQ1 analogs will help researchers develop potent JQ1 compounds with improved inhibitory properties against malignant cells. Furthermore, we explored the potential application of JQ1 analogs in PROTAC technology. The brief history of the bromodomain family of proteins, as well as the obstacles connected with PROTAC technology, can help comprehend the context of the current research, which has the potential to improve the drug development process. Overall, this review comprehensively appraises JQ1 molecules and their prior implementation in PROTAC technology and cancer therapy.

Genome-Wide Identification and Characterization of the BRD Family in Nile Tilapia (Oreochromis niloticus)

Simple Summary

Nile tilapia is a good model for genome-wide identification and examination of the expression and role of gene families. In this study, we identified 54 bromodomain genes (BRDs) divided into eight subfamilies in Nile tilapia. Phylogenetic analysis revealed a high conservation of the BRDs family in vertebrates, with BRDs expansion due to fish-specific duplications. Most of the BRDs displayed sexually dimorphic expression in the gonads at 90 and 180 dah (days after hatching), including 21 testis-dominated genes (brdt, brd4a and brd2b, etc.), and 9 ovary-dominated genes (brd3b, brd2a and kat2a, etc.). Male fish treated with JQ1 (BET subfamily inhibitor) displayed abnormal spermatogenesis. The numbers of germ cells were reduced and the expression of steroidogenic enzyme genes was downregulated, while the expression of apoptosis-promoting genes was elevated in the testes of treated fish.

Abstract

The bromodomain (BRD) proteins specifically recognize the N-acetyllysine motifs, which is a key event in the reading process of epigenetic marks. BRDs are evolutionarily highly conserved. Over recent years, BRDs attracted great interest because of their important roles in biological processes. However, the genome-wide identification of this family was not carried out in many animal groups, in particular, in teleosts. Moreover, the expression patterns were not reported for any of the members in this family, and the role of the BRD family was not extensively studied in fish reproduction. In this study, we identified 16 to 120 BRD genes in 24 representative species. BRDs expanded significantly in vertebrates. Phylogenetic analysis showed that the BRD family was divided into eight subfamilies (I–VIII). Transcriptome analysis showed that BRDs in Nile tilapia (Oreochromis niloticus) exhibited different expression patterns in different tissues, suggesting that these genes may play different roles in growth and development. Gonadal transcriptome analysis showed that most of the BRDs display sexually dimorphic expression in the gonads at 90 and 180 dah (days after hatching), including 21 testis-dominated genes (brdt, brd4a and brd2b, etc.), and nine ovary-dominated genes (brd3b, brd2a and kat2a, etc.). Consistent with transcriptomic data, the results of qRT-PCR and fluorescence in situ hybridization showed that brdt expression was higher in the testis than in the ovary, suggesting its critical role in the spermatogenesis of the tilapia. Male fish treated with JQ1 (BET subfamily inhibitor) displayed abnormal spermatogenesis. The numbers of germ cells were reduced, and the expression of steroidogenic enzyme genes was downregulated, while the expression of apoptosis-promoting genes was elevated in the testis tissue of treated fish. Our data provide insights into the evolution and expression of BRD genes, which is helpful for understanding their critical roles in sex differentiation and gonadal development in teleosts.

Relation of gilthead seabream (Sparus aurata) seasonal reproductive activity to hematology, serum biochemistry, histopathology, and Brdt gene expression

This study aimed to find the relation of Sparus aurata (gilthead seabream) reproductive activities to some blood parameters as complete blood count, liver enzymes, some hormones related to reproduction process and microscopic findings of gonads, as well as expression of Bromodomain testis-specific gene. Eighty-eight sexually mature seabream were collected and investigated through the four seasons. Red blood cells were higher in autumn and spring. Hemoglobin was high in summer, MCV highest values ​​were seen in winter and summer, while MCHC was highest in summer. The values ​​of white blood cells increased significantly in spring, summer, and autumn compared with winter. The highest value of lymphocytes was recorded in spring and autumn. Eosinophil was recorded the highest value in the spring. The highest value of segmented neutrophils was recorded in summer. The highest value of band neutrophil was recorded in summer and winter. Alanine aminotransferase and aspartate aminotransferase showed high values in the winter. Luteinizing hormone (LH) was higher in females, males, and hermaphrodites during winter. Follicle-stimulating hormone (FSH) was higher in females during spring. The highest value of estradiol 17-β and progesterone was recorded in summer. The highest value of total testosterone was recorded in spring. Microscopically, ovaries were immature and inactive during spring and summer but well developed in autumn and winter. During spring and summer, testes were immature and began spermatogenesis process but well developed with the appearance of spermatids and spermatozoa during autumn and winter. The expression of Brdt was higher in testes than ovary. Brdt recorded high expression in autumn and spring than in summer and winter.

Blocking the Bromodomains Function Contributes to Disturbances in Alga Chara vulgaris Spermatids Differentiation

Bromodomain containing (BRD) proteins play an essential role in many cellular processes. The aim of this study was to estimate activity of bromodomains during alga Chara vulgaris spermatids differentiation. The effect of a bromodomain inhibitor, JQ1 (100 μM), on the distribution of individual stages of spermatids and their ultrastructure was studied. The material was Feulgen stained and analysed in an electron microscope. JQ1 caused shortening of the early stages of spermiogenesis and a reverse reaction at the later stages. Additionally, in the same antheridium, spermatids at distant developmental stages were present. On the ultrastructural level, chromatin fibril system disorders and significantly distended endoplasmic reticulum (ER) cisternae already at the early stages were observed. Many autolytic vacuoles were also visible. The ultrastructural disturbances intensified after prolonged treatment with JQ1. The obtained data show that JQ1 treatment led to changes in the spermatid number and disturbances in chromatin condensation and to cytoplasm reduction. The current studies show some similarities between C. vulgaris and mammals spermiogenesis. Taken together, these results suggest that JQ1 interferes with the spermatid differentiation on many interdependent levels and seems to induce ER stress, which leads to spermatid degeneration. Studies on the role of bromodomains in algae spermiogenesis have not been conducted so far.

Histochemistry as a versatile research toolkit in biological research, not only an applied discipline in pathology

The impressive progress of histochemistry over the last 50 years has led to setting up specific and sensitive techniques to describe dynamic events, through the detection of specific molecules in the very place where they exist in live cells. The scientific field where histochemistry has most largely been applied is histopathology, with the aim to identify disease-specific molecular markers or to elucidate the etiopathological mechanisms. Numerous authors did however apply histochemistry to a variety of other research fields; their interests range from the microanatomy of animal and plant organisms to the cellular mechanisms of life. This is especially apparent browsing the contents of the histochemical journals where the articles on subjects other than pathology are the majority; these journals still keep a pivotal role in the field of cell and tissue biology, while being a forum for a diverse range of biologists whose scientific interests expand the research horizon of histochemistry to ever novel subjects. Thus, histochemistry can always receive inspiring stimuli toward a continuous methodological refinement.

Toxicity and non-harmful effects of the soya isoflavones, genistein and daidzein, in embryos of the zebrafish, Danio rerio

Based on the assumed oestrogenic and apoptotic properties of soya isoflavones (genistein, daidzein), and following the current OECD test-guidelines and principle of 3Rs, we have studied the potential toxicity of phytochemicals on the zebrafish embryos test (ZFET). For this purpose, zebrafish embryos at 2-3 h post-fertilisation (hpf) were exposed to both soya isoflavones (from 1.25 mg/L to 20 mg/L) and assayed until 96 hpf. Lethal and sub-lethal endpoints (mortality, hatching rates and malformations) were estimated in the ZFET, which was expanded to potential gene expression markers, determining the lowest observed effect (and transcriptional) concentrations (LOEC, LOTEC), and the no-observable effect (and transcriptional) concentrations (NOEC, NOTEC). The results revealed that genistein is more toxic (LC50-96 hpf: 4.41 mg/L) than daidzein (over 65.15 mg/L). Both isoflavones up-regulated the oestrogen (esrrb) and death receptors (fas) and cyp1a transcript levels. Most thyroid transcript signals were up-regulated by genistein (except for thyroid peroxidase/tpo), and the hatching enzyme (he1a1) was exclusively up-regulated by daidzein (from 1.25 mg/L onwards). The ZFET proved suitable for assessing toxicant effects of both isoflavones and potential disruptions (i.e. oestrogenic, apoptotic, thyroid, enzymatic) during the embryogenesis and the endotrophic larval period.

Is there still room for novelty, in histochemical papers?

Histochemistry continues to be widely applied in biomedical research, being nowadays mostly addressed to detect and locate single molecules or molecular complexes inside cells and tissues, and to relate structural organization and function at the high resolution of the more advanced microscopical techniques. In the attempt to see whether histochemical novelties may be found in the recent literature, the articles published in the European Journal of Histochemistry in the period 2014-2016 have been reviewed. In the majority of the published papers, standardized methods have been preferred by scientists to make their results reliably comparable with the data in the literature, but several papers (approximately one fourth of the published articles) described novel histochemical methods and procedures. It is worth noting that there is a growing interest for minimally-invasive in vivo techniques (magnetic resonance imaging, autofluorescence spectroscopy), which may parallel conventional histochemical analyses to acquire evidence not only on the morphological features of living organs and tissues, but also on their functional, biophysical and molecular characteristics. Thanks to this unceasing methodological refinement, histochemistry will continue to provide innovative applications in the biomedical field.