scholarly journals Spexin and a novel cichlid-specific spexin paralog both inhibit FSH and LH through a specific galanin receptor (Galr2b) in tilapia

2019 ◽  
Author(s):  
Yaron Cohen ◽  
Krist Hausken ◽  
Yoav Bonfil ◽  
Michael Gutnick ◽  
Berta Levavi-Sivan
Keyword(s):  
Mammalian Species ◽  
Cichlid Fish ◽  
Peptide Hormone ◽  
Distribution Patterns ◽  
Cichlid Species ◽  
Amino Acid Peptide ◽  
Lh Cells ◽  
Pleiotropic Functions

AbstractSpexin (SPX) is a 14 amino acid peptide hormone that has pleiotropic functions across vertebrates, one of which is involvement in the brain-pituitary-gonad axis of fish. SPX(1) has been identified in each class of vertebrates, and a second SPX (named SPX2) has been found in some non-mammalian species. We have cloned two spexin paralogs, designated as Spx1a and Spx1b, from Nile tilapia (Oreochromis niloticus) that have varying tissue distribution patterns. Spx1b is a novel peptide only identified in cichlid fish, and is more closely related to Spx1 than Spx2 homologs as supported by phylogenetic, synteny, and functional analyses. Kisspeptin, Spx, and galanin (Gal) peptides and their corresponding kiss receptors and Gal receptors (Galrs), respectively, are evolutionarily related. Cloning of six tilapia Galrs (Galr1a, Galr1b, Galr2a, Galr2b, Galr type 1, and Galr type 2) and subsequent in vitro second-messenger reporter assays for Gαs, Gαq, and Gαi suggests that Gal and Spx activate Galr1a/Galr2a and Galr2b, respectively. A decrease in plasma follicle stimulating hormone and luteinizing hormone concentrations was observed with injections of Spx1a or Spx1b in vivo. Additionally, application of Spx1a to pituitary slices decreased the firing rate of LH cells, suggesting direct inhibition at the pituitary level. These data collectively suggest an inhibitory mechanism of action against the secretion of gonadotropins for a traditional and a novel spexin paralog in cichlid species.

scholarly journals Somatostatin, as a Bridge Between the GH-Axis and the Gth-Axis

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A553-A554
Author(s):  
Naama Mizrahi ◽  
Lian Hollander-Cohen ◽  
Berta Levavi-Sivan
Keyword(s):  
Negative Control ◽  
Post Injection ◽  
Amino Acid Peptide ◽  
Specific Localization ◽  
Transgenic Tilapia ◽  
Lh Cells ◽  
Plasma Gh ◽  
Pka Pathway

Abstract Somatostatin (SST) is a 14-amino acid peptide produced in the hypothalamus of vertebrates, including fish. It regulates many physiological processes such as growth development and metabolic processes in the animal’s body. Negative control of growth hormone in vivo and in vitro was characterized in several fish species such as salmon, goldfish, rainbow trout and tilapia. Although very important, the SST/SST-R system in Nile tilapia (Oreochromis niloticus) was not deeply characterized. The somatostatin system in tilapia possess two ligands (Somatostatin1b and Somatostatin 2), and five receptors (SST-R 1-5). Unlike mammals, in fish, FSH and LH are secreted from different cell populations in the pituitary. By performing cell specific transcriptome analysis of double-labelled transgenic tilapia expressing GFP and RFP in LH or FSH cells, respectively, we identified genes specifically enriched in each cell type. Analysis of the RNA-seq discovered 4 types of SST-Rs: sstr2, sstr3, sstr5 and sstr5x3. The specific localization of each SST-R was identified by In Situ hybridization with specific probes for each of the SST-Rs. SST-R2 and SST-R5x3 were expressed on LH and FSH cells, while SST-R5 was exclusively expressed on LH cells. Interestingly, SST-R3, which was expressed on GH secreting cells, was also expressed on both gonadotropin-secreting cells. Transactivation assays, using COS7 cell line transfected with tilapia SST-Rs together with the reporter plasmid CRE-luc, demonstrated an effect through the cAMP/PKA pathway. Signal transduction analysis demonstrated that SST agonist (Octreotide; IC50 = 0.8-60nM) decreased the cAMP/PKA pathway, while an opposite effect was found when SST antagonist (Cyclosomatostatin; EC50 = 0.1 - 188 nM) was used. To understand the physiological effects of somatostatin on gonadotropins and GH release, we examined the effect of ip injection (100 μg/kg BW) of somatostatin agonist and antagonist on plasma FSH, LH and GH levels. SST agonist decreased plasma GH and FSH levels, as fast as two hours post injection and their levels remained low until the end of the experiment. On the other hand, SST antagonist increased LH and FSH levels two hours post injection, but while FSH levels remained high during the entire experiment, LH levels went back to basal levels afterwards. Our results show - for the first time in fish - a direct effect of SST on gonadotropin release, that could serve as a bridge between the GH-axis and the GTH-axis. The research was funded by the Israel Science Foundation (ISF) no. 1540/17.

Traceable Peptidic Ligands that Target Ghrelin Receptors

2020 ◽  
Vol 21 (10) ◽  
pp. 955-964 ◽  
Author(s):  
Mengjie Liu ◽  
John Wade ◽  
Mohammed Akhter Hossain
Keyword(s):  
In Vivo Imaging ◽  
Peptide Hormone ◽  
Structural Features ◽  
Pharmacological Properties ◽  
Imaging Studies ◽  
Cognate Receptor ◽  
Ghrelin Receptors ◽  
Biochemical Research

: Ghrelin is a 28-amino acid octanoylated peptide hormone that is implicated in many physiological and pathophysiological processes. Specific visualization of ghrelin and its cognate receptor using traceable ligands is crucial in elucidating the localization, functions, and expression pattern of the peptide’s signaling pathway. Here 12 representative radio- and fluorescently-labeled peptide-based ligands are reviewed for in vitro and in vivo imaging studies. In particular, the focus is on their structural features, pharmacological properties, and applications in further biochemical research.

scholarly journals Development of a Topical Insulin Polymeric Nanoformulation for Skin Burn Regeneration: An Experimental Approach

2021 ◽  
Vol 22 (8) ◽  
pp. 4087
Author(s):  
Maria Quitério ◽  
Sandra Simões ◽  
Andreia Ascenso ◽  
Manuela Carvalheiro ◽  
Ana Paula Leandro ◽  
...  
Keyword(s):  
Wound Healing ◽  
Healing Process ◽  
In Vitro Release ◽  
Peptide Hormone ◽  
Plga Nanoparticles ◽  
Wound Healing Process ◽  
Target Area ◽  
Encapsulation Process

Insulin is a peptide hormone with many physiological functions, besides its use in diabetes treatment. An important role of insulin is related to the wound healing process—however, insulin itself is too sensitive to the external environment requiring the protective of a nanocarrier. Polymer-based nanoparticles can protect, deliver, and retain the protein in the target area. This study aims to produce and characterize a topical treatment for wound healing consisting of insulin-loaded poly-DL-lactide/glycolide (PLGA) nanoparticles. Insulin-loaded nanoparticles present a mean size of approximately 500 nm and neutral surface charge. Spherical shaped nanoparticles are observed by scanning electron microscopy and confirmed by atomic force microscopy. SDS-PAGE and circular dichroism analysis demonstrated that insulin preserved its integrity and secondary structure after the encapsulation process. In vitro release studies suggested a controlled release profile. Safety of the formulation was confirmed using cell lines, and cell viability was concentration and time-dependent. Preliminary safety in vivo assays also revealed promising results.

scholarly journals Novel Role for Albumin in Innate Immunity: Serum Albumin Inhibits the Growth of Blastomyces dermatitidis Yeast Form In Vitro

2003 ◽  
Vol 71 (11) ◽  
pp. 6648-6652 ◽  
Author(s):  
Steven Giles ◽  
Charles Czuprynski
Keyword(s):  
Molecular Weight ◽  
Inhibitory Activity ◽  
Mammalian Species ◽  
Blastomyces Dermatitidis ◽  
Low Molecular Weight ◽  
Rat Serum ◽  
Yeast Form ◽  
Domain Iii

ABSTRACT In this study we found that serum inhibitory activity against Blastomyces dermatitidis was principally mediated by albumin. This was confirmed in experiments using albumin from several mammalian species. Analbuminemic rat serum did not inhibit B. dermatitidis growth in vivo; however, the addition of albumin restored inhibitory activity. Inhibitory activity does not require albumin domain III and appears to involve binding of a low-molecular-weight yeast-derived growth factor.

Opioids and testicular activity in the frog, Rana esculenta

1993 ◽  
Vol 137 (1) ◽  
pp. 49-NP ◽  
Author(s):  
F. Facchinetti ◽  
A. R. Genazzani ◽  
M. Vallarino ◽  
M. Pestarino ◽  
A. Polzonetti-Magni ◽  
...  
Keyword(s):  
Physiological Activity ◽  
Mammalian Species ◽  
Rana Esculenta ◽  
Cell Degeneration ◽  
Efferent System ◽  
Naltrexone Treatment ◽  
Nucleus Infundibularis ◽  
The Brain

ABSTRACT The presence and activity of brain, pituitary and testicular β-endorphin (β-EP)-like material have been studied in the frog, Rana esculenta, using reverse-phase high-pressure liquid chromatography, coupled with radioimmunoassay and immunocytochemistry. In-vivo and in-vitro treatments with naltrexone were carried out to assess the putative physiological activity of opioid peptides. β(1–31) and (1–27), together with their acetylated forms, have been identified in brain, pituitary and testis. In particular, β-EP(1–31) concentrations peaked during July in the brain and pituitary, whilst in testes maximum concentrations were found in April and November. β-EP immunoreactivity was present in the brain within the nucleus preopticus and nucleus infundibularis ventralis while positive fibres in the retrochiasmatic regions projected to the median eminence. In the testis, interstitial cells, canaliculi of the efferent system, spermatogonia and spermatocytes showed positive immunostaining for β-EP. In intact animals, naltrexone treatment increased plasma and testicular androgen levels and this effect was confirmed in in-vitro incubations of minced testes. Naltrexone also induced a significant increase in germ cell degeneration. Our results indicated that an opioid system modulates the hypothalamus-pituitary-gonadal axis in the frog, Rana esculenta and, for the first time, we have shown that the testicular activity of a non-mammalian species may be regulated by opiates locally. Journal of Endocrinology (1993) 137, 49–57

scholarly journals Evaluation of a Novel Therapeutic Approach to Treating Severe Pneumococcal Infection Using a Mouse Model

2009 ◽  
Vol 16 (6) ◽  
pp. 806-810 ◽  
Author(s):  
Nikkol Melnick ◽  
Gowrisankar Rajam ◽  
George M. Carlone ◽  
Jacquelyn S. Sampson ◽  
Edwin W. Ades
Keyword(s):  
Single Dose ◽  
Combination Therapy ◽  
Polymorphonuclear Leukocytes ◽  
Low Dose ◽  
Control Level ◽  
Pneumococcal Infection ◽  
Amino Acid Peptide ◽  
Opsonophagocytic Killing

ABSTRACT P4, a 28-amino-acid peptide, is a eukaryotic cellular activator that enhances specific in vitro opsonophagocytic killing of multiple bacterial pathogens. In a previous study, we successfully recreated this phenomenon in mice in vivo by using a two-dose regimen of P4 and pathogen-specific antibodies, which significantly reduced moribundity in mice. For the present study, we hypothesized that the inclusion of a low-dose antibiotic would make it possible to treat the infected mice with a single dose containing a mixture of P4 and a pathogen-specific antibody. A single dose consisting of P4, intravenous immunoglobulin (IVIG), and ceftriaxone effectively reduced moribundity compared to that of untreated controls (n = 10) by 75% (P < 0.05) and rescued all (10 of 10) infected animals (P < 0.05). If rescued animals were reinfected with Streptococcus pneumoniae and treated with a single dose containing P4, IVIG, and ceftriaxone, they could be rerescued. This observation of the repeated successful use of P4 combination therapy demonstrates a low risk of tolerance development. Additionally, we examined the polymorphonuclear leukocytes (PMN) derived from infected mice and observed that P4 enhanced in vitro opsonophagocytic killing (by >80% over the control level; P < 0.05). This finding supports our hypothesis that PMN are activated by P4 during opsonophagocytosis and the recovery of mice from pneumococcal infection. P4 peptide-based combination therapy may offer an alternative and rapid immunotherapy to treat fulminant pneumococcal infection.

Myosin light-chain 1 and 3 gene has two structurally distinct and differentially regulated promoters evolving at different rates

1985 ◽  
Vol 5 (11) ◽  
pp. 3168-3182
Author(s):  
E E Strehler ◽  
M Periasamy ◽  
M A Strehler-Page ◽  
B Nadal-Ginard
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Mammalian Species ◽  
In Vitro Transcription ◽  
Chain Gene ◽  
Promoter Regions ◽  
Light Chain Gene ◽  
Direct Initiation

DNA fragments located 10 kilobases apart in the genome and containing, respectively, the first myosin light chain 1 (MLC1f) and the first myosin light chain 3 (MLC3f) specific exon of the rat myosin light chain 1 and 3 gene, together with several hundred base pairs of upstream flanking sequences, have been shown in runoff in vitro transcription assays to direct initiation of transcription at the cap sites of MLC1f and MLC3f mRNAs used in vivo. These results establish the presence of two separate, functional promoters within that gene. A comparison of the nucleotide sequence of the rat MLC1f/3f gene with the corresponding sequences from mouse and chicken shows that: the MLC1f promoter regions have been highly conserved up to position -150 from the cap site while the MLC3f promoter regions display a very poor degree of homology and even the absence or poor conservation of typical eucaryotic promoter elements such as TATA and CAT boxes; the exon/intron structure of this gene has been completely conserved in the three species; and corresponding exons, except for the regions encoding most of the 5' and 3' untranslated sequences, show greater than 75% homology while corresponding introns are similar in size but considerably divergent in sequence. The above findings indicate that the overall structure of the MLC1f/3f genes has been maintained between avian and mammalian species and that these genes contain two functional and widely spaced promoters. The fact that the structures of the alkali light chain gene from Drosophila melanogaster and of other related genes of the troponin C supergene family resemble a MLC3f gene without an upstream promoter and first exon strongly suggests that the present-day MLC1f/3f genes of higher vertebrates arose from a primordial alkali light chain gene through the addition of a far-upstream MLC1f-specific promoter and first exon. The two promoters have evolved at different rates, with the MLC1f promoter being more conserved than the MLC3f promoter. This discrepant evolutionary rate might reflect different mechanisms of promoter activation for the transcription of MLC1f and MLC3f RNA.

scholarly journals Extracellular vesicle budding is inhibited by redundant regulators of TAT-5 flippase localization and phospholipid asymmetry

2018 ◽  
Vol 115 (6) ◽  
pp. E1127-E1136 ◽  
Author(s):  
Katharina B. Beer ◽  
Jennifer Rivas-Castillo ◽  
Kenneth Kuhn ◽  
Gholamreza Fazeli ◽  
Birgit Karmann ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Extracellular Vesicle ◽  
Endosomal Trafficking ◽  
Vesicle Budding ◽  
Sorting Nexins ◽  
Dnaj Protein ◽  
Membrane Budding ◽  
Pleiotropic Functions

Cells release extracellular vesicles (EVs) that mediate intercellular communication and repair damaged membranes. Despite the pleiotropic functions of EVs in vitro, their in vivo function is debated, largely because it is unclear how to induce or inhibit their formation. In particular, the mechanisms of EV release by plasma membrane budding or ectocytosis are poorly understood. We previously showed that TAT-5 phospholipid flippase activity maintains the asymmetric localization of the lipid phosphatidylethanolamine (PE) in the plasma membrane and inhibits EV budding by ectocytosis in Caenorhabditis elegans. However, no proteins that inhibit ectocytosis upstream of TAT-5 were known. Here, we identify TAT-5 regulators associated with retrograde endosomal recycling: PI3Kinase VPS-34, Beclin1 homolog BEC-1, DnaJ protein RME-8, and the uncharacterized Dopey homolog PAD-1. PI3Kinase, RME-8, and semiredundant sorting nexins are required for the plasma membrane localization of TAT-5, which is important to maintain PE asymmetry and inhibit EV release. PAD-1 does not directly regulate TAT-5 localization, but is required for the lipid flipping activity of TAT-5. PAD-1 also has roles in endosomal trafficking with the GEF-like protein MON-2, which regulates PE asymmetry and EV release redundantly with sorting nexins independent of the core retromer. Thus, in addition to uncovering redundant intracellular trafficking pathways, our study identifies additional proteins that regulate EV release. This work pinpoints TAT-5 and PE as key regulators of plasma membrane budding, further supporting the model that PE externalization drives ectocytosis.

scholarly journals The Usefulness of Retinoic Acid Supplementation during in Vitro Oocyte Maturation for the in Vitro Embryo Production of Livestock: A Review

Animals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 561 ◽  
Author(s):  
Abdelnour ◽  
El-Hack ◽  
Swelum ◽  
Saadeldin ◽  
Noreldin ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Embryo Development ◽  
Oocyte Maturation ◽  
Mammalian Species ◽  
Antioxidant Properties ◽  
Reproductive Function ◽  
Embryonic Growth ◽  
Oxidative Damages

Retinoic acid (RA) is an indigenous metabolite and descriptive physiologically functioning constituent of vitamin A. Retinoids were documented as vital regulators for cell development and distinction, embryonic growth, and reproductive function in both male and female livestock. Previously, RA has been shown to have several positive impacts in vivo and in vitro and critically control many reproductive events, such as oocyte development, follicular growth, and early embryonic growth. In addition, RA manages apoptotic signaling and oxidative damages in cells. Recently, RA has been used widely in assisted reproductive technology fields, especially during in vitro embryo development in various mammalian species, including buffaloes, bovine, goats, sheep, pigs, and rabbits. However, the optimum concentration of RA greatly differs based on the condition of maturation media and species. Based on the obtained findings, it was generally accepted that RA enhances nuclear oocyte maturation, cleavage and maturation rates, blastocyst formation, and embryo development. As such, it possesses antioxidant properties against reactive oxygen species (ROS) and an anti-apoptotic effect through enhancing the transcription of some related genes such as superoxide dismutase, prostaglandin synthase, glutathione peroxidase, peroxiredoxins, and heme oxygenase. Therefore, the current review concludes that an addition of RA (up to 50 nM) has the potential to improve the oocyte maturation media of various species of livestock due to its antioxidant activity.

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