-
Frontiers in Physiology 2019While much effort has been put into understanding vitellogenesis in insects and other organisms, much less is known of this process in ticks. There are several steps... (Review)
Review
While much effort has been put into understanding vitellogenesis in insects and other organisms, much less is known of this process in ticks. There are several steps that facilitate yolk formation in developing oocytes of which the vitellogenin receptor (VgR) is a key component. The tick VgR binds vitellogenin (Vg) circulating in the hemolymph to initiate receptor-mediated endocytosis and its transformation into vitellin (Vn). The conversion of Vg into Vn, the final form of the yolk protein, occurs inside oocytes of the female tick ovary. Vn is critical to tick embryos since it serves as the nutritional source for their development, survival, and reproduction. Recent studies also suggest that pathogenic microbes, i.e., spp., that rely on ticks for propagation and dissemination likely "hitchhike" onto Vg molecules as they enter developing oocytes through the VgR. Suppressing VgR messenger RNA synthesis via RNA interference (RNAi) completely blocked spp. transmission into developing tick oocytes, thereby inhibiting vertical transmission of these pathogenic microbes from female to eggs. To date, VgRs from only four tick species, , , , and , have been fully sequenced and characterized. In contrast, many more VgRs have been described in various insect species. VgR is a critical component in egg formation and maturation that can serve as a precise target for tick control. However, additional research will help identify unique residues within the receptor that are specific to ticks or other arthropod disease vectors while avoiding cross-reactivity with non-target species. Detailed knowledge of the molecular structure and functional role of tick VgRs will enable development of novel vaccines to control ticks and tick-borne diseases.
PubMed: 31178755
DOI: 10.3389/fphys.2019.00618 -
Molecular and Cellular Endocrinology Jun 2024The endocrine system plays a pivotal role in shaping the mechanisms that ensure successful reproduction. With over a million known insect species, understanding the... (Review)
Review
The endocrine system plays a pivotal role in shaping the mechanisms that ensure successful reproduction. With over a million known insect species, understanding the endocrine control of reproduction has become increasingly complex. Some of the key players include the classic insect lipid hormones juvenile hormone (JH) and ecdysteroids, and neuropeptides such as insulin-like peptides (ILPs). Individual endocrine factors not only modulate their own target tissue but also play crucial roles in crosstalk among themselves, ensuring successful vitellogenesis and oogenesis. Recent advances in omics, gene silencing, and genome editing approaches have accelerated research, offering both fundamental insights and practical applications for studying in-depth endocrine signaling pathways. This review provides an updated and integrated view of endocrine factors modulating vitellogenesis and oogenesis in insect females.
Topics: Animals; Female; Vitellogenesis; Oogenesis; Insecta; Juvenile Hormones; Endocrine System
PubMed: 38494046
DOI: 10.1016/j.mce.2024.112211 -
The Journal of Steroid Biochemistry and... May 2019Estrogens exert their biological functions through the estrogen receptors (ERs). In zebrafish, three nuclear estrogen receptors (nERs) named ERα, ERβ1 and ERβ2 and...
Estrogens exert their biological functions through the estrogen receptors (ERs). In zebrafish, three nuclear estrogen receptors (nERs) named ERα, ERβ1 and ERβ2 and one membrane-bound G protein-coupled estrogen receptor (GPER) are identified. Vitellogenin (Vtg) is predominantly expressed in liver and strongly response to the stimulation of estrogen. It has been proposed that all three nERs are functionally involved in vitellogenesis and ERα may act as the major mediator in teleost. However, the role of GPER and its interaction with nERs in this process are not yet defined in teleost species. In the present study, we provide genetic evidence for the functional significance of ERα that the expression of Vtg genes (vtg1, vtg2, vtg3) and their response to estradiol stimulation were significantly decreased in esr1 mutant zebrafish. Activation of ERβ1 and ERβ2 induced Vtg expression through ERα. Moreover, the involvement of GPER in vitellogenesis and its interaction with nERs in zebrafish were firstly proposed in this work. Activation of GPER induced Vtg genes expression while inhibition of GPER significantly attenuated the estrogenic effect on Vtg. Both treatments altered the expression levels of nERs, suggesting GPER acts interactively with nERs. Collectively, the involvement of both nERs and GPER in regulation of vitellogenesis is demonstrated. ERα is the central factor, acting interactively with ERβ1, ERβ2 and GPER, and GPER regulates vitellogenesis directly and interactively with nERs.
Topics: Animals; Estrogen Receptor alpha; Estrogen Receptor beta; Male; Receptors, G-Protein-Coupled; Vitellins; Vitellogenesis; Zebrafish; Zebrafish Proteins
PubMed: 30711474
DOI: 10.1016/j.jsbmb.2019.01.013 -
General and Comparative Endocrinology Jul 2021The juvenile hormone (JH) plays a crucial role in arthropod physiological processes, e.g., the regulation of metamorphosis, development, and reproduction (the...
The juvenile hormone (JH) plays a crucial role in arthropod physiological processes, e.g., the regulation of metamorphosis, development, and reproduction (the vitellogenesis, the development of gonads, egg production). Still, data about this sesquiterpenoid hormone in spiders (Araneae) are rudimentary and equivocal. The presence of the JH or its precursors (e.g. methyl farnesoate) is not confirmed in spiders. The site of synthesis of its is still undetermined. No receptors of the JH are identified in spiders and thus, the molecular mechanism of action of this group of hormones is still unknown. Here we show by using the phylogenetic analysis and qPCR method the presence of the transcript of the enzyme catalyzing the last phase of the JH biosynthesis pathway (epox CYP15A1), the JH receptor (Met), and a possible candidate to the methyl farnesoate receptor (USP) in the various tissues and stages of ontogenesis in both sexes of spider Parasteatoda tepidariorum. Our results indicate that the juvenile hormone and/or methyl farnesoate presence is possible in the species of spider P. tepidariorum. The presence of the Ptepox CYP15A1 gene suggests that the main site of the juvenile hormone synthesis can be the integument and not the Schneider organ 2. It also seems that the juvenile hormone and/or methyl farnesoate can be hormones with biological activity due to the presence of the transcript of insect and crustacean JH/MG receptor - Met. The Ptepox CYP15A1, PtMet, and Ptusp expression are sex-, tissue-and time-specific. This study is the first report about the presence of the Ptepox CYP15A1 and PtMet transcripts in the Arachnida, which may indicate the presence of the juvenile hormone and/or methyl farnesoate in spiders.
Topics: Animals; Female; Juvenile Hormones; Male; Metamorphosis, Biological; Phylogeny; Spiders; Vitellogenesis
PubMed: 33862048
DOI: 10.1016/j.ygcen.2021.113781 -
Bioscience, Biotechnology, and... 2016In crustaceans, various physiological events, such as molting, vitellogenesis, and sex differentiation, are regulated by peptide hormones. To understanding the... (Review)
Review
In crustaceans, various physiological events, such as molting, vitellogenesis, and sex differentiation, are regulated by peptide hormones. To understanding the functional sites of these hormones, many structure-activity relationship (SAR) studies have been published. In this review, the author focuses the SAR of crustacean hyperglycemic hormone-family peptides and androgenic gland hormone and describes the detailed results of our and other research groups. The future perspectives will be also discussed.
Topics: Amino Acid Sequence; Animals; Crustacea; Hormones; Peptides; Sequence Homology, Amino Acid; Structure-Activity Relationship
PubMed: 26624010
DOI: 10.1080/09168451.2015.1116932 -
Frontiers in Physiology 2019Vitellogenins are a family of yolk proteins that are by far the most abundant among oviparous animals. In the model nematode , the 6 vitellogenins are among the most... (Review)
Review
Vitellogenins are a family of yolk proteins that are by far the most abundant among oviparous animals. In the model nematode , the 6 vitellogenins are among the most highly expressed genes in the adult hermaphrodite intestine, which produces copious yolk to provision eggs. In this article we review what is known about the vitellogenin genes and proteins in , in comparison with vitellogenins in other taxa. We argue that the primary purpose of abundant vitellogenesis in is to support post-embryonic development and fertility, rather than embryogenesis, especially in harsh environments. Increasing vitellogenin provisioning underlies several post-embryonic phenotypic alterations associated with advancing maternal age, demonstrating that vitellogenins can act as an intergenerational signal mediating the influence of parental physiology on progeny. We also review what is known about vitellogenin regulation - how tissue-, sex- and stage-specificity of expression is achieved, how vitellogenins are regulated by major signaling pathways, how vitellogenin expression is affected by extra-intestinal tissues and how environmental experience affects vitellogenesis. Lastly, we speculate whether vitellogenins may play other roles in worm physiology.
PubMed: 31551797
DOI: 10.3389/fphys.2019.01067 -
The Journal of Steroid Biochemistry and... Jul 2023Estrogen receptors (ERs) were known as estrogen-activated transcription factors and function as major reproduction regulators in vertebrates. The presence of er genes...
Estrogen receptors (ERs) were known as estrogen-activated transcription factors and function as major reproduction regulators in vertebrates. The presence of er genes had been reported in Molluscan cephalopods and gastropods. However, they were considered as constitutive activators with unknown biological functions since reporter assays for these ERs did not show a specific response to estrogens. In this study, we tried characterization of ER orthologues from the Yesso scallop, Patinopecten yessoensis, in which estrogens had been proven to be produced in the gonads and involved in the spermatogenesis and vitellogenesis. Identified ER and estrogen related receptor (ERR) of Yesso scallops, designated as py-ER and py-ERR, conserved specific domain structures for a nuclear receptor. Their DNA binding domains showed high similarities to those of vertebrate ER orthologues, while ligand binding domains had low similarities with them. Both the py-er and py-err expression levels decreased in the ovary at the mature stage while py-vitellogenin expression increased in the ovary by quantitative real-time RT-PCR. Also, the py-er and py-err showed higher expressions in the testis than ovary during the developing and mature period, suggesting both genes might function in the spermatogenesis and testis development. The py-ER showed binding affinities to vertebrate estradiol-17β (E). However, the intensity was weaker than the vertebrate ER, indicating scallops might exist endogenous estrogens with a different structure. On the other hand, the binding property of py-ERR to E was not confirmed in this assay, speculating that py-ERR was a constitutive activator as other vertebrate ERRs. Further, the py-er was localized in the spermatogonia in the testis and in the auxiliary cells in the ovary by in situ hybridization, indicating its potential roles in promoting spermatogenesis and vitellogenesis. Taken together, the present study demonstrated that py-ER was an authentic E receptor in the Yesso scallop and might have functions for the spermatogonia proliferation and vitellogenesis, while py-ERR was involved in the reproduction by undiscovered manners.
Topics: Male; Animals; Female; Receptors, Estrogen; Gonads; Pectinidae; Estrogens
PubMed: 36990165
DOI: 10.1016/j.jsbmb.2023.106302 -
Cellular Signalling Jan 2023Ovarian function in teleosts, like in other vertebrates, is regulated by two distinct gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH).... (Review)
Review
Ovarian function in teleosts, like in other vertebrates, is regulated by two distinct gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Gonadotropin effects are mediated by membrane-bound G protein-coupled receptors localized on the surface of follicle cells. Gonadotropin receptor activation results in increased intracellular cAMP, the most important second cellular signaling molecule. FSH stimulation induces the production of 17β-estradiol in the cells of growing follicles to promote vitellogenesis in oocytes. In contrast, in response to LH, fully grown post-vitellogenic follicles gain the ability to synthesize maturation-inducing steroids, which induce meiotic resumption and ovulation. All these events were induced downstream of cAMP. In this review, we summarize studies addressing the role of the cAMP pathway in gonadotropin-induced processes in teleost ovarian follicles. Furthermore, we discuss future problems concerning cAMP signaling in relation to teleost ovarian function and the differences and similarities in the gonadotropin-induced cAMP signaling pathways between mammals and teleosts.
Topics: Female; Animals; Follicle Stimulating Hormone; Luteinizing Hormone; Ovarian Follicle; Ovulation; Gonadotropins; Mammals
PubMed: 36273754
DOI: 10.1016/j.cellsig.2022.110499 -
Frontiers in Endocrinology 2020Early studies recognizing the importance of the decapod eyestalk in the endocrine regulation of crustacean physiology-molting, metabolism, reproduction, osmotic balance,... (Review)
Review
Early studies recognizing the importance of the decapod eyestalk in the endocrine regulation of crustacean physiology-molting, metabolism, reproduction, osmotic balance, etc.-helped found the field of crustacean endocrinology. Characterization of putative factors in the eyestalk using distinct functional bioassays ultimately led to the discovery of a group of structurally related and functionally diverse neuropeptides, crustacean hyperglycemic hormone (CHH), molt-inhibiting hormone (MIH), gonad-inhibiting hormone (GIH) or vitellogenesis-inhibiting hormone (VIH), and mandibular organ-inhibiting hormone (MOIH). These peptides, along with the first insect member (ion transport peptide, ITP), constitute the original arthropod members of the crustacean hyperglycemic hormone (CHH) superfamily. The presence of genes encoding the CHH-superfamily peptides across representative ecdysozoan taxa has been established. The objective of this review is to, aside from providing a general framework, highlight the progress made during the past decade or so. The progress includes the widespread identification of the CHH-superfamily peptides, in particular in non-crustaceans, which has reshaped the phylogenetic profile of the superfamily. Novel functions have been attributed to some of the newly identified members, providing exceptional opportunities for understanding the structure-function relationships of these peptides. Functional studies are challenging, especially for the peptides of crustacean and insect species, where they are widely expressed in various tissues and usually pleiotropic. Progress has been made in deciphering the roles of CHH, ITP, and their alternatively spliced counterparts (CHH-L, ITP-L) in the regulation of metabolism and ionic/osmotic hemostasis under (eco)physiological, developmental, or pathological contexts, and of MIH in the stimulation of ovarian maturation, which implicates it as a regulator for coordinating growth (molt) and reproduction. In addition, experimental elucidation of the steric structure and structure-function relationships have given better understanding of the structural basis of the functional diversification and overlapping among these peptides. Finally, an important finding was the first-ever identification of the receptors for this superfamily of peptides, specifically the receptors for ITPs of the silkworm, which will surely give great impetus to the functional study of these peptides for years to come. Studies regarding recent progress are presented and synthesized, and prospective developments remarked upon.
Topics: Animals; Arthropod Proteins; Crustacea; Invertebrate Hormones; Multigene Family; Nerve Tissue Proteins
PubMed: 33117290
DOI: 10.3389/fendo.2020.578958 -
The Journal of Experimental Biology Feb 2020The present study investigated the effect of arachidonic acid (AA) and selected prostaglandins on the regulation of vitellogenesis, ecdysteroidogenesis and methyl...
The present study investigated the effect of arachidonic acid (AA) and selected prostaglandins on the regulation of vitellogenesis, ecdysteroidogenesis and methyl farnesoate (MF) synthesis in the freshwater crab and the giant mud crab, Administration of AA and prostaglandin F (PGF) and prostaglandin E (PGE) significantly increased ovarian index, oocyte diameter and ovarian vitellogenin levels and ecdysteroid and MF levels in the hemolymph of crabs. Secretions of MF and ecdysteroids from cultured mandibular organs (MO) and Y-organs (YO) isolated from intermolt crabs injected with AA, PGF and PGE were greater when compared with controls. In contrast, injection of prostaglandin D (PGD) had no effect on vitellogenesis, ecdysteroid and MF levels in circulation. secretion of MF from MO explants isolated from avitellogenic crabs incubated with AA, PGF and PGE increased in a time-dependent manner. Conversely, incubation of YOs isolated from avitellogenic crabs with AA, PGF and PGE had no effect on secretion of ecdsyteroids. These results implicate prostaglandins in the regulation of reproduction by inducing the synthesis of MF and consequent ecdysteroid synthesis in brachyuran crabs, and provide an alternative molecular intervention mechanism to the traditional eyestalk ablation methodology to induce vitellogenesis and ovarian maturation in crustaceans.
Topics: Animals; Arachidonic Acid; Brachyura; Ecdysteroids; Fatty Acids, Unsaturated; Female; Prostaglandins; Species Specificity; Vitellogenesis
PubMed: 31953363
DOI: 10.1242/jeb.212381