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Reproduction in Domestic Animals =... Apr 2017Peroxidation damage to spermatozoa and seminal plasma has an important role in sperm quality. Thus, the objective of this study was to determine the levels of lipid and...
Peroxidation damage to spermatozoa and seminal plasma has an important role in sperm quality. Thus, the objective of this study was to determine the levels of lipid and protein oxidation in spermatozoa and seminal plasma of Asian elephants (Elephas maximus) with varying percentage of progressive motility. Lipid and protein oxidation was measured by the thiobarbituric acid-reactive species (TBARS) assay and the 2, 4-dinitrophenylhydrazine (DNPH) carbonyl groups assay, respectively. Fresh semen samples were collected from Asian elephants and classified according to the percentage of motile spermatozoa into good (>60%) and poor (≤20%) motility. Results revealed that seminal plasma malondialdehyde (MDA) and seminal plasma protein carbonyls (PCs) were significantly higher in poor motility than in good motility (p < .05). The MDA and PC levels in seminal plasma were negatively correlated with the percentages of progressive motility (p < .05). In addition, the negative correlation between sperm concentration and seminal plasma MDA level was investigated (p < .05). The sperm viability was also negatively correlated with sperm PC level (p < .05). This study indicated that lipid and protein oxidation has deleterious effect on semen quality of Asian elephants.
Topics: Animals; Elephants; Lipid Peroxidation; Lipids; Male; Malondialdehyde; Protein Carbonylation; Proteins; Semen; Spermatozoa
PubMed: 28058745
DOI: 10.1111/rda.12900 -
Handbook of Experimental Pharmacology 2017Cannabinoid receptors are fundamentally involved in all aspects of intestinal physiology, such as motility, secretion, and epithelial barrier function. They are part of... (Review)
Review
Cannabinoid receptors are fundamentally involved in all aspects of intestinal physiology, such as motility, secretion, and epithelial barrier function. They are part of a broader entity, the so-called endocannabinoid system which also includes their endocannabinoid ligands and the ligands' synthesizing/degrading enzymes. The system has a strong impact on the pathophysiology of the gastrointestinal tract and is believed to maintain homeostasis in the gut by controlling hypercontractility and by promoting regeneration after injury. For instance, genetic knockout of cannabinoid receptor 1 leads to inflammation and cancer of the intestines. Derivatives of Δ-tetrahydrocannabinol, such as nabilone and dronabinol, activate cannabinoid receptors and have been introduced into the clinic to treat chemotherapy-induced emesis and loss of appetite; however, they may cause many psychotropic side effects. New drugs that interfere with endocannabinoid degradation to raise endocannabinoid levels circumvent this obstacle and could be used in the future to treat emesis, intestinal inflammation, and functional disorders associated with visceral hyperalgesia.
Topics: Animals; Endocannabinoids; Gastric Juice; Gastrointestinal Diseases; Gastrointestinal Motility; Gastrointestinal Tract; Humans; Intestinal Secretions; Receptors, Cannabinoid; Signal Transduction
PubMed: 28161834
DOI: 10.1007/164_2016_105 -
Methods in Molecular Biology (Clifton,... 2021Over the last four decades, chromaffin cells originating from the adrenal medulla have been probably one of the most popular cell models to study neurosecretion at the...
Over the last four decades, chromaffin cells originating from the adrenal medulla have been probably one of the most popular cell models to study neurosecretion at the molecular level. Accordingly, numerous seminal discoveries in the field, including the characterization of role of the cytoskeleton, fusogenic lipids, and soluble N-ethylmaleimide-sensitivefactor attachment protein receptor (SNARE) proteins, have been made using this model. In this chapter, we describe a standard method currently used to isolate and culture bovine chromaffin cells, and we illustrate a catecholamine secretion assay based on the successive transformation of adrenaline into adrenochrome and adrenolutine for fluorescence measurements. We also provide some guidelines for efficient cell recovery and for the use of this assay in the laboratory.
Topics: Adrenal Medulla; Animals; Bodily Secretions; Cattle; Cell Culture Techniques; Chromaffin Cells
PubMed: 33222134
DOI: 10.1007/978-1-0716-1044-2_11 -
The British Journal of Dermatology Dec 2017As lipids are known to regulate macrophage functions, it is reasonable to suppose that a sebocyte-macrophage axis mediated by sebum lipids may exist.
BACKGROUND
As lipids are known to regulate macrophage functions, it is reasonable to suppose that a sebocyte-macrophage axis mediated by sebum lipids may exist.
OBJECTIVES
To investigate if sebocytes could contribute to the differentiation, polarization and function of macrophages with their secreted lipids.
METHODS
Oil Red O lipid staining and Raman spectroscopy were used to assess the dermal lipid content and penetration. Immunohistochemistry was used to analyse the macrophage subsets. Human peripheral blood monocytes were differentiated in the presence of either supernatant from human SZ95 sebocytes or major sebum lipid components and activated with Propionibacterium acnes. Macrophage surface markers and their capacity to uptake fluorescein isothiocyanate-conjugated P. acnes were detected by fluorescence-activated cell sorting measurements. Cytokine protein levels were evaluated by enzyme-linked immunosorbent assay and Western blot analysis.
RESULTS
Sebaceous gland-rich skin had an increased dermal lipid content vs. sebaceous gland-poor skin to which all the tested sebum component lipids could contribute by penetrating the dermoepidermal barrier. Of the lipids, oleic acid and linoleic acid promoted monocyte differentiation into alternatively activated macrophages. Moreover, linoleic acid also had an anti-inflammatory effect in P. acnes-activated macrophages, inhibiting the secretion of interleukin (IL)-1β, IL-6 and tumour necrosis factor (TNF)-α. Squalene, palmitic acid, stearic acid and oleic acid augmented the secretion of IL-1β, even in the absence of P. acnes, whereas oleic acid had a selective effect of inducing IL-1β but downregulating IL-6 and TNF-α secretion.
CONCLUSIONS
Our results suggest a role for sebaceous glands in modulating innate immune responses via their secreted lipids that are of possible pathological and therapeutic relevance.
Topics: Cell Differentiation; Cell Polarity; Cytokines; Humans; Immunity, Innate; Lipid Metabolism; Lipids; Macrophage Activation; Macrophages; Phagocytosis; Propionibacterium acnes; Sebaceous Glands; Sebum
PubMed: 28646583
DOI: 10.1111/bjd.15754 -
Frontiers in Cellular and Infection... 2023Enteropathogenic (EPEC) is a diarrheagenic pathogen and one of the major causes of gastrointestinal illness in developing countries. EPEC, similar to many other...
INTRODUCTION
Enteropathogenic (EPEC) is a diarrheagenic pathogen and one of the major causes of gastrointestinal illness in developing countries. EPEC, similar to many other Gram-negative bacterial pathogens, possesses essential virulence machinery called the type III secretion system (T3SS) that enables the injection of effector proteins from the bacteria into the host cytoplasm. Of these, the translocated intimin receptor (Tir) is the first effector to be injected, and its activity is essential for the formation of attaching and effacing lesions, the hallmark of EPEC colonization. Tir belongs to a unique group of transmembrane domain (TMD)-containing secreted proteins, which have two conflicting destination indications, one for bacterial membrane integration and another for protein secretion. In this study, we examined whether TMDs participate in the secretion, translocation, and function of Tir in host cells.
METHODS
We created Tir TMD variants with the original or alternative TMD sequence.
RESULTS
We found that the C-terminal TMD of Tir (TMD2) is critical for the ability of Tir to escape integration into the bacterial membrane. However, the TMD sequence was not by itself sufficient and its effect was context-dependent. Moreover, the N-terminal TMD of Tir (TMD1) was important for the postsecretion function of Tir at the host cell.
DISCUSSION
Taken together, our study further supports the hypothesis that the TMD sequences of translocated proteins encode information crucial for protein secretion and their postsecretion function.
Topics: Type III Secretion Systems; Cytoplasm; Protein Transport; Bodily Secretions; Enteropathogenic Escherichia coli; Receptors, Cell Surface; Escherichia coli Proteins
PubMed: 36864885
DOI: 10.3389/fcimb.2023.1103552 -
Drug Discovery Today Aug 2015Chitosan, a nontoxic and biocompatible polysaccharide, has been widely explored for the gastrointestinal delivery of drugs, proteins, peptides and genes for different... (Review)
Review
Chitosan, a nontoxic and biocompatible polysaccharide, has been widely explored for the gastrointestinal delivery of drugs, proteins, peptides and genes for different therapeutic purposes. Because a pH gradient exists in the gastrointestinal tract, chitosan-based formulations in response to specific pH conditions, such as the low pH in the stomach and a high pH in the intestine, have been developed as a general strategy for disease diagnosis and therapy. Tailored pH-responsive drug release in the gastrointestinal tract can be achieved with various chitosan-based formulations such as nanoparticles, microspheres, hydrogels and nanocomposites. This review focuses on the most recent development of chitosan-based pH-sensitive formulations for gastrointestinal delivery, covering various types of chitosan-based formulations, their pH-responsive mechanisms and biomedical applications.
Topics: Administration, Oral; Animals; Chemistry, Pharmaceutical; Chitosan; Delayed-Action Preparations; Drug Carriers; Gastric Juice; Gastrointestinal Absorption; Humans; Hydrogen-Ion Concentration; Intestinal Secretions; Pharmaceutical Preparations; Technology, Pharmaceutical
PubMed: 25769687
DOI: 10.1016/j.drudis.2015.03.002 -
International Journal of Molecular... Dec 2023Sjögren's Disease (SjD) is an autoimmune disorder associated with decreased saliva and/or tear secretions, resulting in patients reporting dryness in the mouth and... (Review)
Review
Sjögren's Disease (SjD) is an autoimmune disorder associated with decreased saliva and/or tear secretions, resulting in patients reporting dryness in the mouth and eyes. Serum autoantibodies directed against the Ro60/SS-A and La/SS-B autoantigens are a distinctive feature of the disease. Analysis of the saliva and tear proteomes represents one promising alternative method of both classifying and monitoring the condition, and research into salivary and tear proteomics in patients with SjD, with and without sicca, has shown its efficacy and practicality in both clinical and research settings. Studies analyzing the saliva proteomics of SjD patients have generally shown an overexpression of proteins involved in T-cell activation, the immune response, β-2 microglobulin, and the recruitment of pro-inflammatory agents. These studies also show a decrease in or downregulation of proteins involved in salivary secretion. Studies analyzing the tear proteomics of patients with SjD have generally indicated an upregulation of proteins involved with TNF-α signaling, B-cell survival, and the recruitment of pro-inflammatory agents. Studies also note the differential expression of tear protein folding as a hallmark of ocular involvement in this condition. These findings help to elucidate the biochemical relationship between the proteomes of saliva/tear fluids and the general pathophysiology of the gland involved with the pathogenesis of this condition, giving further credence to the potential role of salivary and tear proteomics in the future of diagnosis and treatment for patients with SjD.
Topics: Humans; Proteome; Proteomics; Sjogren's Syndrome; Tears; Saliva
PubMed: 38139325
DOI: 10.3390/ijms242417497 -
Current Opinion in Microbiology Oct 2020Many bacterial pathogens rely on dedicated secretion systems to translocate virulence proteins termed 'effectors' into host cells. These effectors engage and manipulate... (Review)
Review
Many bacterial pathogens rely on dedicated secretion systems to translocate virulence proteins termed 'effectors' into host cells. These effectors engage and manipulate host cellular functions to support bacterial colonization and propagation. The secretion systems are molecular machines that recognize targeting 'features' in these effector proteins in vivo to selectively and efficiently secrete them. The joint analysis of whole genome sequencing data and computational predictions of amino acid characteristics of effector proteins has made available extensive lists of candidate effectors for many bacterial pathogens, among which Dot/Icm type IVB secretion system in Legionella pneumophila reigns with the largest number of effectors identified to-date. This system is also used by the causative agent of Q fever, Coxiella burnetii, to secrete a large pool of distinct effectors. By comparing these two pathogens, we provide an understanding of the rationale behind effector repertoire expansion. We will also discuss recent bioinformatic advances facilitating high-throughput discovery of secreted effectors through in silico 'feature' recognition, and the current challenge to substantiate the biological relevance and bona fide nature of effectors identified in silico.
Topics: Bacteria; Bacterial Proteins; Bacterial Secretion Systems; Computer Simulation; Genome, Bacterial; Protein Transport
PubMed: 32505919
DOI: 10.1016/j.mib.2020.04.002 -
Basic & Clinical Pharmacology &... Mar 2015Viscoelastic mucus lines all mucosal surfaces of the body and forms a potential barrier to mucosal drug delivery. Mucus is mainly composed of water and mucins; high... (Review)
Review
Viscoelastic mucus lines all mucosal surfaces of the body and forms a potential barrier to mucosal drug delivery. Mucus is mainly composed of water and mucins; high molecular weight glycoproteins forming an entangled network. Consequently, mucus forms a steric barrier, and due to its negative charge and hydrophobic domains, the overall hydrophilic mucus also presents an interactive barrier limiting the free diffusion of components within and through the mucus. Furthermore, mucus is a dynamic barrier due to its continuous secretion and shedding from the mucosal surfaces. Mucus is thus a highly complex gel barrier to drug delivery. Current knowledge of mucus characteristics and barrier properties, as achieved by state-of-the-art methodologies, is the topic of this MiniReview emphasizing the gastrointestinal mucus and an overall focus on oral drug delivery. Cell culture-based in vitro models are well-established as essential tools in drug research and development, but traditionally, mucus-containing models have only rarely been applied. However, a number of mucus-containing in vitro models have recently been described in the literature, and their properties and applications will be reviewed and discussed. Finally, studies of peptide and protein drug diffusion in and through mucus and studies of mucus-penetrating nanoparticles are included to illustrate the mucus as a potentially important barrier to obtain sufficient bioavailability of orally administered drugs, and thus an important parameter to address in the development of future oral drug delivery systems.
Topics: Administration, Oral; Animals; Biological Availability; Drug Delivery Systems; Drug Design; Humans; Models, Biological; Mucins; Mucus; Nanoparticles; Peptides; Proteins
PubMed: 25349046
DOI: 10.1111/bcpt.12342 -
Arteriosclerosis, Thrombosis, and... Apr 2017AUP1 (ancient ubiquitous protein 1) is an endoplasmic reticulum-associated protein that also localizes to the surface of lipid droplets (LDs), with dual role in protein...
OBJECTIVE
AUP1 (ancient ubiquitous protein 1) is an endoplasmic reticulum-associated protein that also localizes to the surface of lipid droplets (LDs), with dual role in protein quality control and LD regulation. Here, we investigated the role of AUP1 in hepatic lipid mobilization and demonstrate critical roles in intracellular biogenesis of apoB100 (apolipoprotein B-100), LD mobilization, and very-low-density lipoprotein (VLDL) assembly and secretion. APPROACH AND RESULTS: siRNA (short/small interfering RNA) knockdown of AUP1 significantly increased secretion of VLDL-sized apoB100-containing particles from HepG2 cells, correcting a key metabolic defect in these cells that normally do not secrete much VLDL. Secreted particles contained higher levels of metabolically labeled triglyceride, and AUP1-deficient cells displayed a larger average size of LDs, suggesting a role for AUP1 in lipid mobilization. Importantly, AUP1 was also found to directly interact with apoB100, and this interaction was enhanced with proteasomal inhibition. Knockdown of AUP1 reduced apoB100 ubiquitination, decreased intracellular degradation of newly synthesized apoB100, and enhanced extracellular apoB100 secretion. Interestingly, the stimulatory effect of AUP1 knockdown on VLDL assembly was reminiscent of the effect previously observed after MEK-ERK (mitogen-activated protein kinase kinase-extracellular signal-regulated kinase) inhibition; however, further studies indicated that the AUP1 effect was independent of MEK-ERK signaling.
CONCLUSIONS
In summary, our findings reveal an important role for AUP1 as a regulator of apoB100 stability, hepatic LD metabolism, and intracellular lipidation of VLDL particles. AUP1 may be a crucial factor in apoB100 quality control, determining the rate at which apoB100 is degraded or lipidated to enable VLDL particle assembly and secretion.
Topics: Apolipoprotein B-100; Apoptosis Regulatory Proteins; Carrier Proteins; Hep G2 Cells; Hepatocytes; Humans; Lipid Droplets; Lipoproteins, VLDL; Liver; Membrane Proteins; Particle Size; Proteasome Endopeptidase Complex; Protein Binding; Protein Stability; Proteolysis; RNA Interference; Transfection; Triglycerides; Ubiquitination
PubMed: 28183703
DOI: 10.1161/ATVBAHA.117.309000