Phospholipase C gamma (PLCγ) regulates soluble trehalase in the 20E-induced fecundity of Apolygus lucorum.

Apolygus lucorum is the dominant pathogenic insect attacking Bacillus thuringiensis (Bt) cotton in China. Additionally, 20-hydroxyecdysone (20E) has important functions in many biological processes, including insect reproduction. Phospholipase C (PLC), which is an essential enzyme for phosphoinositide metabolism, is involved in 20E signal transduction, but its function in 20E-mediated reproduction in A. lucorum remains unclear. In this study, 20E increased AlPLCγ transcription as well as the abundance and activity of the encoded protein during molting and metamorphosis. The 20E treatment also induced the considerable accumulation of two second messengers, inositol triphosphate and diacylglycerol. The expression levels of genes encoding vitellogenin (AlVg) and soluble trehalase (AlTre-1) were similar to those of AlPLCγ, and were upregulated in response to 20E. The silencing of AlPLCγ resulted in downregulated expression of AlTre-1 and AlVg. However, the silencing of AlTre-1 and AlVg did not affect AlPLCγ expression. Moreover, the silencing of AlVg did not alter AlTre-1 expression. Furthermore, an examination of the insect specimens indicated that AlPLCγ is required for female adult reproduction, and that downregulated expression of this gene is associated with decreases in fecundity, adult longevity, and egg hatching rate as well as delayed oocyte maturation. We propose that 20E regulates AlTre-1 expression via AlPLCγ and affects Vg expression as well as ovary development to facilitate the reproductive activities of A. lucorum females.

Ecdysis triggering hormone is essential for larva-pupa-adult transformation in Leptinotarsa decemlineata.

In Drosophila melanogaster, ecdysis triggering hormone (ETH) is the key factor triggering ecdysis behaviour and promoting trachea clearance. However, whether ETH plays the dual roles in non-dipteran insects is unknown. In this survey, we found that Ldeth mRNA levels were positively correlated with circulating 20-hydroxyecdysone (20E) titers in Leptinotarsa decemlineata. Ingestion of an ecdysteroid agonist halofenozide or 20E stimulated the transcription of Ldeth, whereas RNA interference (RNAi) of ecdysteroidogenesis (LdPTTH or LdSHD) or 20E signalling (LdEcR, LdUSP or LdFTZ-F1) genes inhibited the expression, indicating ETH acts downstream of 20E. RNAi of Ldeth at the final instar stage impaired pupation. More than 80% of the Ldeth-depleted beetles remained as prepupae, completely wrapped in the old larval cuticles. These prepupae became withered, dried and darkened gradually, and finally died in soil. The remaining Ldeth hypomorphs pupated and emerged as abnormal adults, bearing smaller and wrinkle elytrum and hindwing. Moreover, the tracheae in the Ldeth hypomorphs were full of liquid. We accordingly proposed that the failure of trachea clearance disenabled air-swallowing after pupa-adult ecdysis and impacted wing expansion. Our results suggest that ETH plays the dual roles, initiation of ecdysis and motivation of trachea clearance, in a coleopteran.

20-Hydroxyecdysone Primes Innate Immune Responses That Limit Bacterial and Malarial Parasite Survival in Anopheles gambiae.

Blood feeding is an integral behavior of mosquitoes to acquire nutritional resources needed for reproduction. This requirement also enables mosquitoes to serve as efficient vectors to acquire and potentially transmit a multitude of mosquito-borne diseases, most notably malaria. Recent studies suggest that mosquito immunity is stimulated following a blood meal, independent of infection status. Since blood feeding promotes production of the hormone 20-hydroxyecdysone (20E), we hypothesized that 20E plays an important role in priming the immune response for pathogen challenge. Here, we examine the immunological effects of priming Anopheles gambiae with 20E prior to pathogen infection, demonstrating a significant reduction in bacteria and Plasmodium berghei survival in the mosquito host. Transcriptome sequencing (RNA-seq) analysis following 20E treatment identifies several known 20E-regulated genes, as well as several immune genes with previously reported function in antipathogen defense. Together, these data demonstrate that 20E influences cellular immune function and antipathogen immunity following mosquito blood feeding, arguing the importance of hormones in the regulation of mosquito innate immune function.IMPORTANCE Blood feeding is required to provide nutrients for mosquito egg production and serves as a mechanism to acquire and transmit pathogens. Shortly after a blood meal is taken, there is a peak in the production of 20-hydroxyecdysone (20E), a mosquito hormone that initiates physiological changes, including yolk protein production and mating refractoriness. Here, we examine additional roles of 20E in the regulation of mosquito immunity, demonstrating that priming the immune system with 20E increases mosquito resistance to pathogens. We identify differentially expressed genes in response to 20E treatment, including several involved in innate immune function as well as lipid metabolism and transport. Together, these data argue that 20E stimulates mosquito cellular immune function and innate immunity shortly after blood feeding.

Detection and quantitation of ecdysterone in human serum by liquid chromatography coupled to tandem mass spectrometry.

The polyhydroxylated phytosteroid ecdysterone is present in various plants (e.g. spinach). It is widely marketed as the active component of dietary supplements, due to its reported health and performance promoting effects. For evaluation of its actual bioavailability, a fast and sensitive method was developed, optimized and validated for human serum. Instrumental analysis was performed utilizing liquid chromatography-tandem mass spectrometry with positive electrospray ionization and acquisition in multiple reaction mode. Solid phase extraction and dilute-and-inject (following protein precipitation) were tested to isolate ecdysterone from human serum. Both methods were compared in the light of the preset analytical target profile. The limit of detection (LOD) and quantitation (LOQ) for ecdysterone in human serum after SPE extraction corresponded to 0.06 ng/mL and 0.14 ng/mL, respectively, meeting the requested sensitivity of the method. The assay was linear over the range of 0.10 ng/mL to 20.83 ng/mL. As expected, the sensitivity of the SPE method was better than that of the dilute-and-inject procedure, which did not allow for quantitation of all post administration serum samples. Accuracy (relative error; %) and precision (coefficient of variation; %), were both within acceptance criteria (<15%). The developed method was successfully applied to a ten week intervention study conducted in young men performing regular resistance training. Different doses of supplements containing ecdysterone from spinach extract have been administered during the study and the quantitation of ecdysterone in serum samples has been successfully conducted. Ecdysterone could be quantified in all post-administration samples using solid phase extraction (SPE) for sample pretreatment.

Ecdysteroids as non-conventional anabolic agent: performance enhancement by ecdysterone supplementation in humans.

Recent studies suggest that the anabolic effect of ecdysterone, a naturally occurring steroid hormone claimed to enhance physical performance, is mediated by estrogen receptor (ER) binding. In comparison with the prohibited anabolic agents (e.g., metandienone and others), ecdysterone revealed to be even more effective in a recent study performed in rats. However, scientific studies in humans are very rarely accessible. Thus, our project aimed at investigating the effects of ecdysterone-containing products on human sport exercise. A 10-week intervention study of strength training of young men (n = 46) was carried out. Different doses of ecdysterone-containing supplements have been administered during the study to evaluate the performance-enhancing effect. Analysis of blood and urine samples for ecdysterone and potential biomarkers of performance enhancement has been conducted. To ensure the specificity of the effects measured, a comprehensive screening for prohibited performance-enhancing substances was also carried out. Furthermore, the administered supplement has been tested for the absence of anabolic steroid contaminations prior to administration. Significantly higher increases in muscle mass were observed in those participants that were dosed with ecdysterone. The same hypertrophic effects were also detected in vitro in C2C12 myotubes. Even more relevant with respect to sports performance, significantly more pronounced increases in one-repetition bench press performance were observed. No increase in biomarkers for liver or kidney toxicity was noticed. These data underline the effectivity of an ecdysterone supplementation with respect to sports performance. Our results strongly suggest the inclusion of ecdysterone in the list of prohibited substances and methods in sports in class S1.2 "other anabolic agents".

ß­ecdysterone protects against apoptosis by promoting autophagy in nucleus pulposus cells and ameliorates disc degeneration.

Increasing cell apoptosis is one of the major causes of intervertebral disc degeneration (IDD). ß-ecdysterone has been demonstrated to protect PC12 cells against neurotoxicity. A previous study revealed that ß­ecdysterone may be involved in the regulation of autophagy in osteoblasts. Therefore, we hypothesized that ß­ecdysterone may possess therapeutic effects on IDD via autophagy stimulation. The effect of ß­ecdysterone on IDD was explored by in vitro experiments. The results demonstrated that ß­ecdysterone attenuated the apoptosis induced by tert­butyl hydroperoxide via promoting autophagy in nucleus pulposus cells. Beclin­1, an indispensable protein for the stimulation of autophagy, is upregulated and stabilized by ß­ecdysterone in a dose­ and time­dependent manner in nucleus pulposus cells. Inhibition of autophagy with 3­methyladenine partially abrogated the protective function of ß­ecdysterone against apoptosis of nucleus pulposus cells, indicating that autophagy participated in the protective effect of ß­ecdysterone on IDD. Additionally, ß­ecdysterone promoted the expression of anabolic genes while inhibiting the expression of catabolic genes in nucleus pulposus cells. Collectively, the present study demonstrated that ß­ecdysterone may protect nucleus pulposus cells against apoptosis by autophagy stimulation and ameliorate disc degeneration, which indicates that ß­ecdysterone may be a potential therapeutic agent for IDD.

Experimental diabetes induced by streptozotocin in the desert gerbil, Gerbillus gerbillus, and the effects of short-term 20-hydroxyecdysone administration.

The present work was aimed at studying the effects of streptozotocin (STZ; 130 mg/kg) in the desert gerbil, Gerbillus gerbillus, and at evaluating the impact of the short-term administration of 20-hydroxyecdysone (20E; 5 mg/kg). We observed that administration of streptozotocin caused a significant increase in plasmatic glucose and a decrease in insulin levels. The plasma lipid profile and liver glycogen content were also altered. The activities of antioxidant enzymes and malondialdehyde (MDA) levels were increased in the pancreatic tissue of STZ-treated gerbils. Moreover, histopathological and immunohistochemical analysis showed degenerative damage in the pancreas with a decline in the percentage area of ß-cells. Treatment of STZ-treated gerbils with 20E counteracted metabolic disorders and reduced lipid peroxidation. Histological and immunohistochemical studies showed moderate amelioration in the pancreatic structure. These findings indicate that streptozotocin administration induced experimental diabetes in gerbils and that short-term administration of 20E has beneficial effects in glucose homeostasis in STZ-treated gerbils suggesting that 20E may stimulate surviving ß-cells to release more insulin.

Effect of 20-Hydroxyecdysone on Proteolytic Regulation in Skeletal Muscle Atrophy.

BACKGROUND/AIM: 20-Hydroxyecdystone (20E) is an ecdysteroid hormone which controls molting and reproduction in arthropods. 20E also produces a variety of effects in vertebrates, including enhancing protein synthesis and skeletal muscle regeneration. The effect of 20E on disuse muscle atrophy has not been reported to date. This study examined the proteolytic regulation of 20E in tenotomized rat slow soleus and fast plantaris muscles. MATERIALS AND METHODS: Male Wistar rats were randomly divided into three groups: sedentary control (CON), tenotomy without 20E treatment (TEN), and tenotomy with treatment of 5 mg/kg BW of 20E (TEN+20E). The TEN+20E group was administered 20E via subcutaneous injection to the right thigh for 7 days after tenotomy. RESULTS: 20E treatment tended to attenuate disuse muscle atrophy and reduced ubiquitination only in soleus muscle. CONCLUSION: 20E treatment alleviates skeletal muscle atrophy partially mediated by ubiquitinate pathway, dependent on the muscle phenotype.

Desiccation stress induces developmental heterochrony in Drosophila melanogaster.

Stressful environments are known to perturb developmental patterns in insects. In the purview of desiccation as a stressor, relatively little is known about the developmental consequences linked with desiccation tolerance. In this study, we have particularly focused on the exploration of the temporal profile of postembryonic development in response to desiccation exposure in Drosophila melanogaster and the associated trade-offs. We document a correlation between variations in 20-hydroxyecdysone levels and the altered timing of metamorphic events during the life cycle. Following desiccation, we observed an extension in the larval longevity whereas the duration of the pupal and adult stages was significantly shortened. Alternately, feeding of 20-hydroxyecdysone apparently led to the restoration of the normal temporal pattern of development in the desiccated group. In spite of the desiccation-responsive heterochronic shifts in development, the overall lifespan post recovery remained almost unaltered among the desiccated and undesiccated groups suggesting plasticity in developmental control. This observation reminisces 'canalization-like' phenomenon that buffers alterations in the overall lifespan. We thus identified a desiccationresponsive period in the lifespan of D. melanogaster during which variations in ecdysone levels are capable to alter the temporal course of development.

Comprehensive physiology and toxicology of ecdysogens--The metabolically activated porphyrin-ecdysteroid complexes in insects.

The polyhydroxylated derivatives of 6-keto,7-dehydrocholesterol (ecdysone, ecdysteroids, Ecd) are natural compounds widely distributed in plants. They exhibit strong anabolic, vitamin D-like, pharmacological effects in vertebrate animals and in the human body. In the larval stages of insects, injections of pure Ecd cause serious pathophysiological, "hyperecdysonic" syndromes associated with neuromuscular paralysis, premature cuticular apolysis and complete inhibition of ecdysis. Ecds do not penetrate insect cuticle. For this reason, all previous attempts to induce ecdysone responses by topical applications of Ecd failed. In this work, we tried to induce the topical effects of Ecd by preparation of more lipophilic complexes, with 2 or 4 molecules of 20-hydroxyecdysone (E20) attached to a relatively large nucleus of the porphyrin. The resulting porphyrin-E20 complexes (ecdysogens) have been subjected to standardised assays for ecdysone activity in the ligatured larvae ("dauerlarvae") of the greater waxmoth (Galleria mellonella). Similarly like the free E20 alone, porphyrin-E20 complexes had no effect when applied on the body surface or administered in the larval diet. When injected, however, they exhibited delayed effects, but the adverse ("hyperecdysonic") pathophysiological syndromes were reduced or abolished. It is concluded, therefore, that the replacement of pathophysiological, precocious or "hyperecdysonic" moults by the larval-pupal transformation, was due to successive metabolic liberation of the biologically active, free E20 from the porphyrin-E20 complex. The biological status of Ecd does not agree with their definition as the prothoracic gland (PG) hormone of insects, nor with the assumptions about a growth hormone of plants. A possibility that the most important status of Ecd may depend on the pharmacological properties of a sterolic D6 vitamin has been discussed.

Pharmaceutical Composition for Improving Physical Working Capacity.

For development of a pharmaceutical composition improving physical performance, effects of various drugs and their combinations on forced swimming test performance were studied on laboratory rats. Maximum increase in animal performance was produced by a 3-component composition asparcam+mildronate+metaprote in proportion of 5.0, 10.7, and 14.3 mg/kg, respectively. No changes in blood serum biochemistry and morphological composition of the peripheral blood were detected after single intragastric administration of the composition.

Phytoecdysteroids as modulators of the Toxoplasma gondii growth rate in human and mouse cells.

BACKGROUND: Searching for new effective drugs against human and animal toxoplasmosis we decided to test the anti-Toxoplasma potential of phytoecdysteroids (α-ecdysone and 20-hydroxyecdysone) characterized by the pleiotropic activity on mammalian organisms including the enhancement of host's anti-parasitic defence. This objective was accomplished by the in vitro evaluation of T. gondii growth in phytoecdysteroid-treated immunocompetent cells of selected hosts: humans and two strains of inbred mice with genetically determined different susceptibility to toxoplasmosis. METHODS: Peripheral mononuclear blood cells were isolated from Toxoplasma-positive and Toxoplasma-negative women (N = 43) and men (N = 21). Non-infected mice (C57BL/6, N = 10 and BALB/c, N = 14) and mice (BALB/c, N = 10) challenged intraperitoneally with 5 tissue cysts of the T. gondii DX strain were also used in this study as a source of splenocytes. The effects of phytoecdysteroids on the viability of human PBMC and mouse splenocytes were evaluated using the MTT assay. The influence of phytoecdysteroids on PBMCs, splenocytes and T. gondii proliferation was measured using radioactivity tests (the level of 3[H] uracil incorporation by toxoplasms or 3[H] thymidine by PBMCs and splenocytes), which was confirmed by quantitative Real-Time PCR. Statistical analysis was performed using SigmaStat 3.5 (Systat Software GmbH). The best-fit IC50 curves were plotted using GraphPad Prism 6.0 (GraphPad Software, Inc.). RESULTS: Our results showed that phytoecdysteroids promote the multiplication of Toxoplasma in cultures of human or murine immune cells, in contrast to another apicomplexan parasite, Babesia gibsoni. Additionally, the tested phytoecdysteroids did not stimulate the in vitro secretion of the essential protective cytokines (IFN-γ, IL-2 and IL-10), neither by human nor by murine immune cells involved in an effective intracellular killing of the parasite. CONCLUSIONS: Judging by the effect of phytoecdysteroids on the T. gondii proliferation, demonstrated for the first time in this study, it seems that these compounds should not be taken into consideration as potential medications to treat toxoplasmosis. Phytoecdysteroids included in the food are most likely not harmful for human or animal health but certain nutrients containing ecdysteroids at high concentrations could promote T. gondii proliferation in chronically infected and immunocompromised individuals. In order to assess the real impact of ecdysteroids on the course of natural T. gondii invasion, in vivo research should be undertaken because it cannot be ruled out that the in vivo effect will be different than the in vitro one. However, taking into account the possible stimulating effect of ecdysteroids on some opportunistic parasites (such as Toxoplasma or Strongyloides) further studies are necessary and should focus on the mechanisms of their action, which directly or indirectly enhance the parasite growth. Since ecdysteroids are considered as potential drugs, it is essential to determine their effect on various parasitic pathogens, which may infect the host at the same time, especially in immunocompromised individuals.

ß-Ecdysone Augments Peak Bone Mass in Mice of Both Sexes.

BACKGROUND: One of the strongest predictors for osteoporosis is peak bone mass. Interventions to augment peak bone mass have yet to be developed. ß-Ecdysone (ßEcd), a natural steroid-like compound produced by arthropods to initiate metamorphosis, is believed to have androgenic effects and so may be used to augment bone mass. QUESTIONS/PURPOSES: The purpose of this study was to use both male and female (1) gonadal-sufficient; and (2) -insufficient mice to investigate sex differences in terms of bone development and structure after ßEcd administration. METHODS: Two-month-old male and female Swiss-Webster mice were randomized to receive either vehicle or ßEcd (0.5 mg/kg) for 3 weeks. In a separate experiment to evaluate the effects of ßEcd on sex hormone-deficient mice, gonadectomy was performed in male (orchiectomy [ORX]) and female mice (ovariectomy [OVX]). Sham-operated and the ORX/OVX mice were then treated for 3 weeks with ßEcd. Primary endpoints for the study were trabecular bone structure and bone strength. RESULTS: In male mice, the trabecular bone volume was 0.18±0.02 in the placebo-treated (PL) and 0.23±0.02 in the ßEcd-treated group (p<0.05 versus PL); and 0.09±0.01 in the ORX group (p<0.05 versus PL) and 0.12±0.01 in the ORX+ßEcd group. Vertebral bone strength (maximum load) was 43±2 in PL and 51±1 in the ßEcd-treated group (p<0.05 versus PL); and 30±4 in the ORX group (p<0.05 versus PL) and 37±3 in the ORX+ßEcd group. In female mice, trabecular bone volume was 0.23±0.02 in PL and 0.26±0.02 in the ßEcd-treated group (p<0.05 versus PL); and 0.15±0.01 in the OVX group (p<0.05 versus PL) and 0.14±0.01 in the OVX+ßEcd group. Maximum load of the vertebrae was 45±2 in PL and 48±4 in the ßEcd-treated group; and 39±4 in the OVX group (p<0.05 versus PL) and 44±4 in the OVX+ßEcd group. CONCLUSIONS: These findings suggest the potential use of ßEcd in the augmentation of bone mass in growing male and female mice. It may also partially prevent the detrimental effects of gonadectomy on trabecular bone. CLINICAL RELEVANCE: Our results support the potential use of ßEcd or nature products that are rich in ßEcd to augment peak bone mass. ßEcd may differ from the other anabolic hormone treatments that may have severe side effects such as serious cardiac complications. However, its effects on humans remain to be determined.

Frataxin inactivation leads to steroid deficiency in flies and human ovarian cells.

Friedreich ataxia (FA), the most common inherited autosomal-recessive ataxia in Caucasians, is characterized by progressive degeneration of the central and peripheral nervous system, hypertrophic cardiomyopathy and increased incidence of diabetes. FA is caused by a GAA repeat expansion in the first intron of the gene encoding frataxin, an evolutionarily conserved mitochondrial protein, which results in decreased gene expression. Ubiquitous inactivation of the fly frataxin ortholog dfh blocks the transition from larval to pupal stages. In this study, we show that this phenotype is due to ecdysteroid deficiency and that feeding larvae with the 20-hydroxyecdysone steroid hormone rescues this developmental blockage. In mammals, adrenodoxin, the ferredoxin FDX1, is an Fe-S-containing protein essential for the synthesis of various steroid hormones. We show here that the two fly ferredoxins, Fdxh and Fdxh2 (encoded by CG1319), are also involved in steroidogenesis. This provides a potent mechanism by which frataxin, known to be involved in Fe-S cluster biosynthesis, could affect steroidogenesis through reduced ferredoxin activity. Finally, we show that frataxin inactivation decreases progesterone synthesis in human KGN ovarian granulosa cells. Thus, the involvement of frataxin in steroid synthesis appears to be a conserved function of the protein from flies to human and our data suggest that steroidogenesis could be affected in FA patients.

24-epibrassinolide and 20-hydroxyecdysone affect photosynthesis differently in maize and spinach.

The aim of the work was to examine the effect of brassinosteroid (24-epibrassinolide; 24E) and ecdysteroid (20-hydroxyecdysone; 20E) on various parts of primary photosynthetic processes in maize and spinach. Additionally, the effect of steroids on gaseous exchange, pigment content and biomass accumulation was studied. The efficiency of the photosynthetic whole electron-transport chain responded negatively to the 24E or 20E treatment in both species, but there were interspecific differences regarding Photosystem (PS) II response. A positive effect on its oxygen-evolving complex and a slightly better energetical connectivity between PSII units were observed in maize whereas the opposite was true for spinach. The size of the pool of the PSI end electron acceptors was usually diminished due to 24E or 20E treatment. The treatment of plants with 24E or 20E applied individually positively influenced the content of photosynthetic pigments in maize (not in spinach). On the other hand, it did not affect gaseous exchange in maize but resulted in its reduction in spinach. Plants treated with combination of both steroids mostly did not significantly differ from the control plants. We have demonstrated for the first time that 20E applied in low (10nM) concentration can affect various parts of photosynthetic processes similarly to 24E and that brassinosteroids regulate not only PSII but also other parts of the photosynthetic electron transport chain - but not necessarily in the same way.

Function of the nuclear receptor FTZ-F1 during the pupal stage in Drosophila melanogaster.

The nuclear receptor ßFTZ-F1 is expressed in most cells in a temporally specific manner, and its expression is induced immediately after decline in ecdysteroid levels. This factor plays important roles during embryogenesis, larval ecdysis, and early metamorphic stages. However, little is known about the expression pattern, regulation and function of this receptor during the pupal stage. We analyzed the expression pattern and regulation of ftz-f1 during the pupal period, as well as the phenotypes of RNAi knockdown or mutant animals, to elucidate its function during this stage. Western blotting revealed that ßFTZ-F1 is expressed at a high level during the late pupal stage, and this expression is dependent on decreasing ecdysteroid levels. By immunohistological analysis of the late pupal stage, FTZ-F1 was detected in the nuclei of most cells, but cytoplasmic localization was observed only in the oogonia and follicle cells of the ovary. Both the ftz-f1 genetic mutant and temporally specific ftz-f1 knockdown using RNAi during the pupal stage showed defects in eclosion and in the eye, the antennal segment, the wing and the leg, including bristle color and sclerosis. These results suggest that ßFTZ-F1 is expressed in most cells at the late pupal stage, under the control of ecdysteroids and plays important roles during pupal development.

Characterization of the response to ecdysteroid of a novel cuticle protein R&R gene in the honey bee, Apis cerana cerana.

Genes encoding cuticle proteins are helpful subjects to study the molecular mechanisms of insect molting and metamorphosis. In this study, we isolated and characterized a novel cuticle protein R&R gene, referred to as AccCPR1, from Apis cerana cerana. The open reading frame of AccCPR1 has a length of 573 nt and encodes a protein of 190 amino acids that contains a chitin binding region and is a typical cuticle R&R-2 protein. Five putative E74 binding sites and four BR-C binding sites were predicted in the 5'-flanking region, which suggests a potential function in molting and metamorphosis. RT-qPCR showed that AccCPR1 transcript occurred as the ecdysteroid titer decreased after reaching a peak, which suggests AccCPR1 expression requires a "pulse" regimen of ecdysteroids. This hypothesis was tested using different experimental strategies. When larvae were reared with different concentrations of 20E in their diet, the ecdysteroid peak repressed AccCPR1 expression. Exposure of the thoracic integument of the pupae in vitro to different concentration of 20E repressed AccCPR1 expression, which recovered after the removal of 20E. These results suggest that AccCPR1 is a typical cuticle R&R-2 protein that plays an important role in development, and an ecdysteroid pulse is critical for high AccCPR1 gene expression.

cDNA cloning and expression analysis of myostatin/GDF11 in shrimp, Litopenaeus vannamei.

Myostatin (MSTN) and growth differentiation factor-11 (GDF11) are closely related proteins belonging to the transforming growth factor-ß (TGF-ß) superfamily. In vertebrates, MSTN is known to negatively regulate skeletal muscle growth, and GDF11 is found to inhibit neurogenesis. In invertebrates, only one ortholog of vertebrate MSTN and GDF11 (MSTN/GDF11) existed. Little attention has been paid on its role to date. In this study, the cDNA that encodes a 422-amino-acid MSTN/GDF11 protein (LvMSTN/GDF11) was characterized from a crustacean species, the Pacific white shrimp (Litopenaeus vannamei). Sequence analysis revealed that the overall protein sequence and specific functional sites of LvMSTN/GDF11 were highly conserved with those in other crustacean species. Expression analysis by quantitative real-time reverse transcription polymerase chain reaction technique demonstrated its tissue-specific, larval developmental stage-specific, and molt stage-specific expression pattern, respectively. After in vivo injections of 20 hydroxyecdysone (20E), LvMSTN/GDF11 transcripts were declined in the abdominal (A) and pleopod (P1) muscles, increased in the pereiopod (P2) muscle, and not affected in the thoracic (T) muscle. The observed expression profiles suggest multiple functions of LvMSTN/GDF11 in L. vannamei and its role differs during the larval development and natural molt cycle. The different responses of LvMSTN/GDF11 to acute increases of 20E in the A, P1, P2 and T muscles may indicate that LvMSTN/GDF11 is transcriptionally regulated via ecdysteroids to coincide with its specific roles in the former three muscles, while its role may be independent of 20E regulation in the T muscle.

20-Hydroxyecdysone protects against oxidative stress-induced neuronal injury by scavenging free radicals and modulating NF-κB and JNK pathways.

Oxidative stress plays an important role in the pathological processes of ischemic brain damage. Many antioxidants have been shown to protect against cerebral ischemia injury by inhibiting oxidative stress both in vitro and in vivo. 20-Hydroxyecdysone (20E), an ecdysteroid hormone, exhibits antioxidative effects. For the work described in this paper, we used an in vitro oxidative damage model and an in vivo ischemic model of middle cerebral artery occlusion (MCAO) to investigate the neuroprotective effects of 20E and the mechanisms related to these effects. Treatment of cells with H(2)O(2) led to neuronal injury, intracellular ROS/RNS generation, mitochondrial membrane potential dissipation, cellular antioxidant potential descent, an increase in malondialdehyde (MDA) and an elevation of intracellular [Ca(2+)], all of which were markedly attenuated by 20E. Inhibition of the activation of the ASK1-MKK4/7-JNK stress signaling pathway and cleaved caspase-3 induced by oxidative stress were involved in the neuroprotection afforded by 20E. In addition, 20E reduced the expression of iNOS protein by inhibition of NF-κB activation. The neuroprotective effect of 20E was also confirmed in vivo. 20E significantly decreased infarct volume and the neurological deficit score, restored antioxidant potential and inhibited the increase in MDA and TUNEL-positive and cleaved caspase-3-positive cells in the cerebral cortex in MCAO rats. Together, these results support that 20E protects against cerebral ischemia injury by inhibiting ROS/RNS production and modulating oxidative stress-induced signal transduction pathways.

The effects of 20-hydroxyecdysone and 17ß-estradiol on the skin of ovariectomized rats.

OBJECTIVE: 20-hydroxyecdysone has numerous favorable effects on a variety of organs, including the skin, where it improves wound healing. It is devoid of estrogenic and androgenic effects. Therefore, application of 20-hydroxyecdysone might be a new approach to improve skin conditions in postmenopausal women, and this was investigated in ovariectomized (OVX) rats. METHODS: After ovariectomy, rats received Ecd (18, 57, or 116 mg/animal/day) or 17ß-estradiol (E2)-3-benzoate (60 µg/kg body weight) in food for 12 weeks, and skin samples were evaluated histologically to quantify two dermal layers, the subcutaneous fat and muscle layers. RESULTS: Epidermal thickness was lowest in the OVX animals, slightly higher in the E2-treated animals, and significantly higher in the Ecd-treated animals. Dermal thickness was lowest in the intact and E2-treated animals and highest in the Ecd-treated animals. The subcutaneous fat layer was thickest in the OVX animals, thinner in the intact animals, and intermediate in the Ecd-treated animals. The muscle layer was smallest in the OVX and intact animals and significantly larger in the E2- and Ecd-treated animals. The number of proliferating cell nuclear antigen antibody-positive cells was lowest in OVX controls and significantly higher in all other groups. CONCLUSIONS: The Ecd-induced increases in epidermal and dermal thickness are suggestive of functional changes of the skin. The decreased amounts of subcutaneous fat in the E2- and Ecd-treated animals point to either a fat catabolic or an antianabolic effect. The ovariectomy-induced decrease in subcutaneous musculature was prevented by Ecd but not by E2. The stimulatory effects of Ecd on epidermal and dermal thickness and the muscle-increasing effects in the skin of OVX rats may indicate functional changes of the skin.