Fruitless (fru) is a conserved transcriptional regulator of sex-specific traits and mating behavior in insects; however, its functions in crustaceans remain largely unknown. In the brine shrimp Artemia franciscana, we identified and characterized a novel fru homolog, which we named Afrfru. The Afrfru gene encodes a BTB-C2H2 zinc-finger transcription factor. Phylogenetic analysis placed the Afrfru protein (AfrFRU) in close proximity to other branchiopod fru homologs. Expression profiling revealed predominant expression in the second antenna of males, while transcript levels peaked during middle oogenesis in females. Knockdown of Afrfru via RNA interference (RNAi) in females disrupted oocyte development and led to abnormal oocyte accumulation. In males, Afrfru RNAi knockdown reduced locomotor velocity and markedly decreased pairing success. To investigate downstream mechanisms, we conducted sex-specific RNA-seq after Afrfru-RNAi. In knockdown females, differentially expressed genes (DEGs) were enriched in glutathione and arachidonic acid metabolism pathways; expression of genes associated with insect hormone biosynthesis and ecdysone synthesis was upregulated. In Afrfru-RNAi males, DEGs predominantly exhibited downregulated expression, particularly among genes involved in cytochrome P450-mediated xenobiotic/drug metabolism, glutathione metabolism, and fatty acid metabolic processes. Together, these results indicate that Afrfru contributed to reproductive maturation and pairing behavior in A. franciscana, likely through sex-specific metabolic and hormonal programs. Our study expands the understanding of reproductive behavior regulation in Artemia and extends the known functional scope of fru beyond insect models.

BACKGROUND & AIMS:Chronic liver injury and its progression to disease often extend beyond exposure to toxic metabolites or xenobiotics. Recovery from chronic injury, when achieved, depends on de novo regeneration, the underlying mechanisms of which remain poorly understood. Herein, we investigate a specific cell population proposed to be fundamental for de novo regeneration and recovery following chronic injury, aiming to elucidate its regulatory mechanisms. METHODS:Setd4-expressing (Setd4+) cells were identified in murine liver tissue by single-molecule fluorescence in situ hybridization. These Setd4+ cells were labeled and lineage traced in Setd4Cre-ERT2/+;Rosa26lsl-tdTomato mice following tamoxifen induction for either 3 days or over 3 weeks. Chronic liver injury was induced by 12 weeks of thioacetamide drinking or 4 weeks of a 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet. Targeted ablation of Setd4+ cells was performed in Setd4CreERT2;Rosa26DTA/+ mice to assess their functional role. The regulatory mechanisms governing the dormant and active states of Setd4+ cells were investigated through analyses of chromatin structure, immunostaining, bulk RNA-seq, and CUT&RUN-seq. RESULTS:We identified a damage-resistant, dormant population of long-lived Setd4+ cells in the murine liver. These cells survived under chronic injury and were then activated to proliferate, facilitating regenerative recovery. Acting as a reserve population, Setd4+ cells initiated de novo regeneration upon loss of less resistant proliferative hepatocytes. Mechanistically, dormant Setd4+ cells maintained a silenced metabolic state under H4K20me3-mediated heterochromatin, enabling survival during chronic injury. Chromatin remodeling then increased accessibility, triggering activation from dormancy and initiating regeneration. CONCLUSIONS:Dormant Setd4+ cells serve as a reserve population that endure chronic injury and, through chromatin remodeling-mediated activation, initiate de novo regeneration, which is fundamental for recovery from chronic liver injury. IMPACT AND IMPLICATIONS:This study identifies dormant Setd4+ cells in midlobular zone 2 as a previously unrecognized reserve population crucial for liver regeneration following chronic injury. By uncovering how H4K20me3-mediated heterochromatin maintains their dormancy and how chromatin remodeling triggers their activation, the findings reveal a fundamental mechanism enabling tissue recovery when conventional hepatocytes fail. Understanding this regenerative reserve provides a new framework for therapeutic strategies aimed at enhancing endogenous repair in chronic liver disease.

Male infertility is a recognized side effect of chemoradiotherapy. Extant spermatogonial stem cells (SSCs) may act as originators for any subsequent recovery. However, which type of SSCs, the mechanism by which they survive and resist toxicity, and how they act to restart spermatogenesis remain largely unknown. Here, we identify a small population of Set domain-containing protein 4 (Setd4)-expressing SSCs that occur in a relatively dormant state in the mouse seminiferous tubule. Extant beyond high-dose chemoradiotherapy, these cells then activate to recover spermatogenesis. Recovery fails when Setd4+ SSCs are deleted. Confirmed to be of fetal origin, these Setd4+ SSCs are shown to facilitate early testicular development and also contribute to steady-state spermatogenesis in adulthood. Upon activation, chromatin remodeling increases their genome-wide accessibility, enabling Notch1 and Aurora activation with corresponding silencing of p21 and p53. Here, Setd4+ SSCs are presented as the originators of both testicular development and spermatogenesis recovery in chemoradiotherapy-induced infertility.

To survive under harsh environments, embryonic development of Artemia was arrested at the gastrula stage and released as the diapause embryo. Cell cycle and metabolism were highly suppressed in this state of quiescence. However, cellular mechanisms underlying diapause remain largely unclear. In this study, we found that the expression level of a CT10 regulator of kinase-encoding gene (Ar-Crk) in diapause embryos was significantly lower than non-diapause embryos at the early embryogenetic stage of Artemia. Knockdown of Ar-Crk by RNA interference induced formation of diapause embryos, while the control group produced nauplii. Western blot analysis and metabolic assays revealed that the diapause embryos produced by Ar-Crk-knocked-down Artemia had similar characteristics of diapause markers, arrested cell cycle, and suppressed metabolism with those diapause embryos produced by natural oviparous Artemia. Transcriptomic analysis of Artemia embryos revealed knockdown of Ar-Crk induced downregulation of the aurora kinase A (AURKA) signaling pathway, as well as energetic and biomolecular metabolisms. Taken together, we proposed that Ar-Crk is a crucial factor in determining the process of diapause in Artemia. Our results provide insight into the functions of Crk in fundamental regulations such as cellular quiescence.

Doublesex (DSX) proteins are members of the Doublesex/mab-3-related (DMRT) protein family and play crucial roles in sex determination and differentiation among the animal kingdom. In the present study, we identified two Doublesex (Dsx)-like mRNA isoforms in the brine shrimp Artemia franciscana (Kellogg 1906), which are generated by the combin-ation of alternative promoters, alternative splicing and alternative polyadenylation. The two transcripts exhibited sex-biased enrichment, which we termed AfrDsx(M) and AfrDsx(F). They share a common region which encodes an identical N-terminal DNA-binding (DM) domain. RT-qPCR analyses showed that AfrDsxM is dominantly expressed in male Artemia while AfrDsx(F) is specifically expressed in females. Expression levels of both iso-forms increased along with the developmental stages of their respective sexes. RNA interference with dsRNA showed that the knockdown of AfrDsx(M) in male larvae led to the appearance of female traits including an ovary-like structure in the original male reproductive system and an elevated expression of vitellogenin. However, silencing of AfrDsx(F) induced no clear phenotypic change in female Artemia. These results indicated that the male AfrDSX(M) may act as inhibiting regulator upon the default female developmental mode in Artemia. Furthermore, electrophoretic mobility shift assay analyses revealed that the unique DM domain of AfrDSXs can specifically bind to promoter segments of poten-tial downstream target genes like AfrVtg. These data show that AfrDSXs play crucial roles in regulating sexual development in Artemia, and further provide insight into the evolution of sex determination/differentiation in sexual organisms.

Some Zinc finger (ZnF) proteins are required for masculinization in silkworms. In the present study, a masculinizer gene (Mr-Masc) with multi-tissue expression is identified in the freshwater prawn Macrobrachium rosenbergii. The Mr-Masc is clustered into a separate branch with ZnF proteins from decapoda by phylogenetic tree analysis. Moreover, Mr-Masc silencing in male postlarvae prawn results in functional sex reversal females known as neo-females, which are applied to all-male monosex offspring breeding. This manipulation has been significant in sexually dimorphic cultured species. In addition, several significantly expressed transcripts are enriched and the effects of crucial signal pathways are focused through the comparative transcriptomic analysis in Mr-Masc gene knockdown. The significantly differentially expressed epidermal growth factor, upregulated low-density lipoprotein receptor, flotillin, and sex-lethal unigenes, downregulated heat shock proteins and forkhead box homologs are focused. The finding offers an innovative perspective on Masc proteins' evolution and physiological function.

Supplementary Table S1 and Supplementary Figure S1 to S11

The brine shrimp (Artemia), releases embryos that can remain dormant for up to a decade. Molecular and cellular level controlling factors of dormancy in Artemia are now being recognized or applied as active controllers of dormancy (quiescence) in cancers. Most notably, the epigenetic regulation by SET domain-containing protein 4 (SETD4), is revealed as highly conserved and the primary control factor governing the maintenance of cellular dormancy from Artemia embryonic cells to cancer stem cells (CSCs). Conversely, DEK, has recently emerged as the primary factor in the control of dormancy exit/reactivation, in both cases. The latter has been now successfully applied to the reactivation of quiescent CSCs, negating their resistance to therapy and leading to their subsequent destruction in mouse models of breast cancer, without recurrence or metastasis potential. In this review, we introduce the many mechanisms of dormancy from Artemia ecology that have been translated into cancer biology, and herald Artemia's arrival on the model organism stage. We show how Artemia studies have unlocked the mechanisms of the maintenance and termination of cellular dormancy. We then discuss how the antagonistic balance of SETD4 and DEK fundamentally controls chromatin structure and consequently governs CSCs function, chemo/radiotherapy resistance, and dormancy in cancers. Many key stages from transcription factors to small RNAs, tRNA trafficking, molecular chaperones, ion channels, and links with various pathways and aspects of signaling are also noted, all of which link studies in Artemia to those of cancer on a molecular and/or cellular level. We particularly emphasize that the application of such emerging factors as SETD4 and DEK may open new and clear avenues for the treatment for various human cancers.

Although parthenogenesis is widespread in nature and known to have close relationships with bisexuality, the transitional mechanism is poorly understood. Artemia is an ideal model to address this issue because bisexuality and "contagious" obligate parthenogenesis independently exist in its congeneric members. In the present study, we first performed chromosome spreading and immunofluorescence to compare meiotic processes of Artemia adopting two distinct reproductive ways. The results showed that, unlike conventional meiosis in bisexual Artemia, meiosis II in parthenogenic Artemia is entirely absent and anaphase I is followed by a single mitosis-like equational division. Interspecific comparative transcriptomics showed that two central molecules in homologous recombination (HR), Dmc1 and Rad51, exhibited significantly higher expression in bisexual versus parthenogenetic Artemia. qRT-PCR indicated that the expression of both genes peaked at the early oogenesis and gradually decreased afterward. Knocking-down by RNAi of Dmc1 in unfertilized females of bisexual Artemia resulted in a severe deficiency of homologous chromosome pairing and produced univalents at the middle oogenesis stage, which was similar to that of parthenogenic Artemia, while in contrast, silencing Rad51 led to no significant chromosome morphological change. Our results indicated that Dmc1 is vital for HR in bisexual Artemia, and the deficiency of Dmc1 may be correlated with or even possibly one of core factors in the transition from bisexuality to parthenogenesis.

The freshwater prawn Macrobrachium rosenbergii is one kind of important economic aquaculture species and displays remarkable sexual dimorphism. The molecular mechanism of sexual differentiation in M. rosenbergii has been primarily unraveled through the research efforts of the androgenic gland and its related genes. However, the understanding of conserved genes involved in the molecular mechanism underpinning sex determination and sexual differentiation of M. rosenbergii is still fragmentary. MroDmrt11E is a member of the doublesex and mab-3-related transcription factor (Dmrt) gene family and is prominently expressed in the testis. In the present study, in vivo knockdown of MroDmrt11E at the postlarva stage in male prawn induced a complete and functional sex reversal and achieved the production of an all-male monosex population. Furthermore, a great deal of new information of upregulated and downregulated transcriptions involved in sexual differentiation of MroDmrt11E knockdown was enriched by comparative transcriptomic analysis. The effects of RNAi-mediated gene knockdown of MroDmrt11E on the differentially expressed and sex-related candidate genes, such as transformer, fruitless, feminization, insulin-like androgenic gland gene, Dmrt gene family, were primarily focused on, and their possible molecular regulatory relationships in sexual differentiation were analyzed. Meanwhile, the response of primary Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathways was investigated to expound the potential roles of MroDmrt11E in male sexual differentiation, which provided a deeper understanding of the molecular regulatory network underlying sexual differentiation of M. rosenbergii. The finding provided a novel sexual manipulation technique through silencing of Dmrt gene family for achieving a complete and functional sex reversal and offered a new insight regarding the mechanism of the Dmrt gene family in the sexual differentiation of crustaceans.

Intestinal epithelial replenishment is fueled by continuously dividing intestinal stem cells (ISCs) resident at the crypt niche. However, the cell type(s) enabling replenishment upon damage and subsequent loss of whole crypts remain largely unclear. Using Set domain-containing protein 4 (Setd4), we identify a small population with reserve stem cell characteristics in the mouse intestine. Upon irradiation-induced injury, Setd4-expressing (Setd4+) cells survive radiation exposure and then activate to produce Sca-1-expressing cell types to restore the epithelial wall and regenerate crypts de novo via crypt fission. Setd4+ cells are confirmed to originate from the early fetal period, subsequently contributing to the development of embryonic gut and the establishment of postnatal crypts. Setd4+ cells are therefore represented as both originators and key regenerators of the intestine.

Due to the lack of precise microstructure and functions of the two-dimensional culture model, the in vitro culture models of lung organoids and lung-on-chips, as two main research tools to mimic lung development, homeostasis, injury, and regeneration, allow further exploration of pulmonary fibrosis, lung cancer, and other diseases. Lung organoid refers to isolated lung epithelial stem cells growing in a three-dimensional environment in vitro to form mini-clusters of cells that self-renew, self-reorganize, and differentiate into functional cell types. Based on the microfluidic chip technology, lung-on-chips use porous flexible membrane made of poly to provide tissue-layered structures for cells and simulate microenvironment and mechanical forces. We reviewed the classification, research and development history, establishment methods, practical applications, advantages and disadvantages of two main in vitro culture models derived from lung adult stem cells, hoping to provide a reference for organ transplantation and regeneration and drug screening.

Tumor therapeutics often target the primary tumor bulk but fail to eradicate therapy-resistant cancer stem cells (CSCs) in quiescent state. These can then become activated to initiate recurrence and/or metastasis beyond therapy. Here, we identified and isolated chemoradiotherapy-resistant CSCs in quiescent state with high capacity of tumor-initiation and tumorsphere formation from three types of breast tumors in mice. Experiments of knockdown and rescue revealed DEK, a nuclear protein, as essential for CSC activation. Exogenous DEK was then used to trigger quiescence exit of CSCs. ChIP-seq and ATAC-seq showed that DEK directly binds to chromatin, facilitating its genome-wide accessibility. The resulting epigenetic events upregulate the expression of cellular activation-related genes including MYC targets, whereas cellular quiescence-related genes including the p53 signaling pathway are silenced. However, twinned with DEK-induced activation, formerly resistant CSCs were then destroyed by chemotherapy in vitro. In mice, traditional chemoradiotherapy concurrent with the injection of DEK-containing exosomes resulted in eradication of primary tumors together with formerly resistant CSCs without recurrence or metastasis. Our findings advance knowledge of the mechanism of quiescent CSC activation and may provide novel clinical opportunities for removal of quiescence-linked therapy resistance.

Cellular quiescence facilitates maintenance of neural stem cells (NSCs) and their subsequent regenerative functions in response to brain injury and aging. However, the specification and maintenance of NSCs in quiescence from embryo to adulthood remain largely unclear. Here, using Set domain-containing protein 4 (SETD4), an epigenetic determinant of cellular quiescence, we mark a small but long-lived NSC population in deep quiescence in the subventricular zone of adult murine brain. Genetic lineage tracing shows that SETD4+ cells appear before neuroectoderm formation and contribute to brain development. In the adult, conditional knockout of Setd4 resulted in quiescence exit of NSCs, generating newborn neurons in the olfactory bulb and contributing to damage repair. However, long period deletion of SETD4 lead to exhaustion of NSC reservoir or SETD4 overexpression caused quiescence entry of NSCs, leading to suppressed neurogenesis. This study reveals the existence of long-lived deep quiescent NSCs and their neurogenetic capacities beyond activation.

As an emerging branch of biology, Synthetic Biology has seen rapid development with great potential in theoretical research and application. With a lot of brand-new concepts and research methods, it brings challenges to university teachers, and little experience is available in China on the teaching of Synthetic Biology. In this study, we discussed the general education-based development and application of the course on Synthetic Biology (a discipline in "liberal arts" in Zhejiang University) from the background, design, implementation, outcome, and problems of the course, hoping to provide a reference for the optimization of the course and the design of similar courses in other universities in China.

肝脏是执行很多重要生理功能的器官,它具有强大的再生能力,在损伤后可以迅速恢复到原本的体积.它的再生特性得益于肝细胞和胆管上皮细胞在损伤后的快速增殖;然而,在极端急性损伤或长期慢性损伤的情况下,肝脏可能无法再生或再生不佳.有众多研究表明,不同的肝损伤模型会动员不同的细胞亚群促进肝再生.该文主要介绍了五种不同的肝脏损伤模型,并对在不同损伤情况下新生肝细胞的来源、胆管上皮细胞与肝细胞的互相转换等方面进行了总结,为肝脏后续相关研究和疾病治疗提供了借鉴.

Blood vessels in the adult mammal exist in a highly organized and stable state. In the ischemic heart, limited expansion capacity of the myocardial vascular bed cannot satisfy demands for oxygen supply and the myocardium eventually undergoes irreversible damage. The predominant contribution of endogenous c-Kit+ cells is understood to be in the development and homeostasis of cardiac endothelial cells, which suggests potential for their targeting in treatments for cardiac ischemic injury. Quiescent cells in other tissues are known to contribute to the long-term maintenance of a cell pool, preserve proliferation capacity and, upon activation, facilitate tissue homeostasis and regeneration in response to tissue injury. Here, we present evidence of a Setd4-expressing quiescent c-Kit+ cell population in the adult mouse heart originating from embryonic stages. Conditional knock-out of Setd4 in c-Kit-CreERT2;Setd4f/f;Rosa26TdTomato mice induced an increase in vascular endothelial cells of capillaries in both neonatal and adult mice. We show that Setd4 regulates quiescence of c-Kit+ cells by the PI3K-Akt-mTOR signaling pathway via H4K20me3 catalysis. In myocardial infarction injured mice, Setd4 knock-out resulted in attenuated cardiomyocyte apoptosis, decreased infarction size and improved cardiac function. Lineage tracing in Setd4-Cre;Rosa26mT/mG mice showed that Setd4+ cells contribute to each cardiac lineage. Overall, Setd4 epigenetically controls c-Kit+ cell quiescence in the adult heart by facilitating heterochromatin formation via H4K20me3. Beyond activation, endogenous quiescent c-Kit+ cells were able to improve cardiac function in myocardial infarction injured mice via the neovascularization of capillaries.

The insulin signalling pathway is one of the most studied pathways, including ovary maturation and female reproduction. However, downstream elements involved in this cascade remain unknown. Here, we identified and characterized an insulin-like receptor (IR) in female Macrobrachium rosenbergii, and named as Mro-IR. The deduced Mro-IR contained conserved domains of IR proteins, including two ligand-binding domains, a furin-like domain, two fibronectin-3 domains, a transmembrane domain and an intracellular tyrosine kinase domain in order. Multiple sequence alignment of the first ligand-binding domain and the tyrosine kinase domain in Mro-IR revealed a high degree of similarity to other representative IRs. Mro-IR was clustered into a separate branch with IRs from decapods by phylogenetic analysis. Additionally, tissue distribution analysis showed that Mro-IR was uniquely expressed in the ovary of M. rosenbergii. This study would possibly provide a new highlight to the molecular mechanism of insulin-like signalling cascade, regulating female sexual differentiation in crustaceans.

In the adult pancreas, the presence of progenitor or stem cells and their potential involvement in homeostasis and regeneration remains unclear. Here, we identify that SET domain-containing protein 4 (SETD4), a histone lysine methyltransferase, is expressed in a small cell population in the adult mouse pancreas. Genetic lineage tracing shows that during pancreatic development, descendants of SETD4 + cells make up over 70% of pancreatic cells and then contribute to each pancreatic lineage during pancreatic homeostasis. SETD4 + cells generate newborn acinar cells in response to cerulein-induced pancreatitis in acinar compartments. Ablation of SETD4 + cells compromises regeneration of acinar cells, in contrast to controls. Our findings provide a new cellular narrative for pancreatic development, homeostasis and response to injury via a small SETD4 + cell population. Potential applications may act to preserve pancreatic function in case of pancreatic disease and/or damage.

Macrobrachium rosenbergii (M. rosenbergii) is an important freshwater cultured prawn with sexual dimorphism. The mechanism of sexual characteristic formation and sex regulation has been poorly understood. One of the greatest challenges is how to verify the physiological function of sex determination and differentiation genes by animal experiments. This paper began with detailed description of the development of the primary sexual characteristics (genital pores and male appendages) of M. rosenbergii by morphological observation and sex molecular marker technique. Secondly, the histomorphology and histology of reproductive system of M. rosenbergii were comprehensively analysed and compared. This paper firstly gave a brief overview of the earliest period, about 2.5 cm in body length, for sex identification and animal experiments on sex determination and differentiation in prawn. This study provided a convenient and noninvasive method for sex identification in the early stage of juvenile prawns.