ARTICLE | doi:10.20944/preprints201804.0028.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: immunomodulatory; Massoia aromatica Becc.; macrophage phagocytosis
Online: 3 April 2018 (03:49:51 CEST)
Massoia (Massoia aromatica Becc., Lauraceae) bark has been widely used as a component of traditional Indonesian medicine. The indigenous people boil or steam the bark for traditional applications. Our preliminary research revealed the potency of Massoia essential oil and its major compound, C-10 Massoialactone as potential immunomodulator in vitro. However, no scientific evidence regarding its in vivo effects is available. Therefore, this study evaluated the potential immunomodulatory effects of Massoia bark infusion on the nonspecific immune response (phagocytosis) of Wistar rats. The aqueous extract of Massoia bark was obtained by boiling pulverized bark in water, and the C-10 massoialactone content of the extract was determined through Thin Layer Chromatography (TLC) densitometry. For the in vitro assay, macrophages were treated with the freeze-dried infusion at the concentrations of 2.5, 5, 10, 20, or 40 μg/mL media. For the in vivo assay, 2-month-old male Wistar rats were divided into 5 groups. The baseline group received distilled water at the dose of 1 mL/100 g BW with the immunostimulant herbal product “X” administered as the positive control at the dose of 0.54 mL/rat. The treatment groups received the infusion at a dose of 100, 300, or 500 mg/100 g BW. Treatments were given orally every day for 14 days. The ability of macrophage cells to phagocyte latex was determined as phagocytic index (PI) and was observed under microscopy with 300 macrophages. The in vitro study revealed that the phagocytic activity of the infusion-treated macrophages significantly increased in comparison with that of the control macrophages in a concentration-dependent manner. Among all treatment concentrations, the concentration of 40 μg/ml provided the highest activity with a PI value of 70.51% ± 1.11%. The results of the in vivo assay confirmed those of the in vitro assay. The results of the present study indicate that Massoia bark can increase the phagocytic activity of rat macrophage cells. Its potential as a naturally derived immunomodulatory agent requires further study.
ARTICLE | doi:10.20944/preprints202111.0094.v1
Subject: Biology, Animal Sciences & Zoology Keywords: Sparus aurata; social stress; hierarchy; cortisol; phagocytosis
Online: 4 November 2021 (08:44:54 CET)
Abstract: Social stress can affect the ability of the fish to respond to various stressors, such as pathogens or environmental variations. In this paper, the effects of social stress on gilt-head bream (Sparus aurata) were investigated. To study the effects of physiological stress, we evaluated biochemical and cellular parameters as cortisol, glucose, lactate, osmolarity and phagocytosis 24 hours after the establishment of social hierarchy. Social hierarchy was determined and characterised by behavioural observation (aggressive acts and feeding order) of the specimens (dominant “α”, subordinate “β” and “γ”). After the establishment of the social hierarchy, we observed that the levels of plasma cortisol and other biochemical stress markers (glucose and lactate) were higher in subordinate individuals than in dominant ones. In addition, the modulation of phagocytic activity of the peritoneal cavity cells (PEC) demonstrated that social stress appeared to affect the immune response. At last, principal component analysis clearly separated the subordinate fish groups from the dominant groups based on stress markers and phagocytic activity of the peritoneal exudates cells.
REVIEW | doi:10.20944/preprints202212.0298.v1
Subject: Life Sciences, Biochemistry Keywords: Endocytosis; Phagocytosis; Pinocytosis; Receptor endocytosis signaling; Chronic diseases
Online: 16 December 2022 (08:07:01 CET)
Endocytosis in mammalian cells is a fundamental cellular machinery that regulates vital physiological processes, such as the absorption of metabolites, release of neurotransmitters, hormonal secretion, cellular defense, and delivery of biomolecules across the plasma membrane. A remarkable characteristic of the endocytic machinery is the sequential assembly of the complex proteins at the plasma membrane followed by transportation of various cargo molecules to different cellular compartments. In all eukaryotic cells, functional characterization of endocytic pathways is based on dynamics of the protein complex modules. To coordinate the assembly and functions of the numerous parts of the endocytic machinery, the endocytic proteins interact significantly within and between the modules. Clathrin dependent and independent endocytosis, caveolar pathway and receptor mediated endocytosis have been attributed in a greater variety of physiological and pathophysiological roles such as, autophagy, metabolism, cell division, apoptosis, cellular defense, and intestinal permeabilization. Notably, any defect or alteration in the endocytic machinery results in the development of pathological consequences associated with human diseases such as cancer, cardiovascular diseases, neurological diseases, and inflammatory diseases. In this review, an in-depth endeavor has made to illustrate the process of endocytosis, and associated mechanisms describing pathological manifestation associated with dysregulated endocytosis machinery.
ARTICLE | doi:10.20944/preprints202007.0532.v1
Subject: Biology, Other Keywords: Phosphatidylinositol; actin remodeling; phagocytosis; dietary fatty acids; Alzheimer’s disease
Online: 22 July 2020 (14:15:35 CEST)
Alzheimer’s disease is one of the neurodegenerative diseases, characterized by the accumulation of abnormal protein deposits, which disrupt the signal transduction in neurons and other glia cells. The pathological protein Tau and amyloid-β contributes to the disrupted microglial signaling pathways, actin cytoskeleton, and cellular receptor expression. The important secondary messenger lipids i.e., phosphatidylinositols are largely affected by protein deposits of amyloid-beta in Alzheimer’s disease. Phosphatidylinositols are the product of different phosphatidylinositol kinases and the state of phosphorylation at D3, D4, and D5 positions of inositol ring. PI 3, 4, 5-P3 involves in phagocytic cup formation and relates actin remodeling whereas PI 4, 5-P2-mediates the process of phagosomes formation and further fusion with early endosome. The necessary activation of actin-binding proteins such as Rac, WAVE complex, and ARP2/3 complex for the actin polymerization in the process of phagocytosis, migration is regulated and maintained by PI 3, 4, 5-P3 and PI 4, 5-P2. Dietary fatty acids depending on their ratio and types of intake influence secondary lipid messenger along with the cellular content of phaphatidylcholine and phosphatidylethanolamine. The deposited Aβ deposits and extracellular Tau seed disrupt levels of phosphatidylinositol and actin cytoskeletal changes that hamper microglia signaling pathways in AD. We hypothesize that being a lipid species intracellular levels of phosphatidylinositol would be regulated by dietary fatty acids. We keen to understand different types of phosphatidylinositol species levels in signaling events such as phagocytosis and actin remodeling owing to the exposure of various types of dietary fatty acids.
ARTICLE | doi:10.20944/preprints202105.0684.v1
Subject: Life Sciences, Biochemistry Keywords: Paracentrotus lividus; Transformers; Trf; 185/333; invertebrate immunity; phagocytosis; model organism
Online: 27 May 2021 (15:09:05 CEST)
Sea urchins are long-living invertebrates with a complex immune system which includes extended families of immune receptors. A central immune gene family in the sea urchins encodes for the Transformer (Trf) proteins. The Trf family was so far studied mainly in the purple sea urchin Strongylocentrotus purpuratus. In this study, we explored this protein family in the Mediterranean Sea urchin Paracentrotus lividus. The PlTrf genes and predicted proteins were found to be highly diverse and showed a typical Trf size range and structure. We found that P. lividus coelomocytes and hemolymph contain different PlTrf protein repertoires with a shared subset which specifically bind E. coli bacteria. Using FACS, we identified five different P. lividus coelomocyte sub-populations with cell surface Trf protein expression. The relative abundance of the Trf-positive cells sharply increased following immune challenge with E. coli bacteria, but not following challenge with LPS or sea urchin pathogen V. penaeicida. Finally, we demonstrated that the phagocytosis of E. coli bacteria by P. lividus phagocytes is mediated through the hemolymph and is inhibited by blocking Trf activity with anti-Trf antibodies. Together, our results suggest collaboration between cellular and humoral Trf-mediated effector arms in the P. lividus specific immune response to pathogens.
ARTICLE | doi:10.20944/preprints201807.0131.v1
Subject: Medicine & Pharmacology, Ophthalmology Keywords: pigmentary glaucoma; ROCK kinase inhibitor; RKI-1447; trabecular meshwork; phagocytosis; cytoskeleton
Online: 9 July 2018 (11:27:28 CEST)
Purpose: This study investigated the hypotensive effect of RKI-1447, a Rho kinase inhibitor, in a porcine ex vivo pigmentary glaucoma model. Methods: Twenty-eight porcine anterior chambers were perfused with medium supplemented with 1.67 × 107 pigment particles/mL for 48 hours before treatment with RKI-1447 (n = 16) or vehicle control (n = 12). Intraocular pressure (IOP) was recorded and outflow facility was calculated. Primary trabecular meshwork cells were exposed to RKI-1447 or vehicle control; effects on the cytoskeleton, motility, and phagocytosis were evaluated. Result: Compared to baseline, the perfusion of pigment caused a significant increase in IOP in the RKI-1447 group (P = 0.003) at 48 hours. Subsequent treatment with RKI-1447 significantly reduced IOP from 20.14 ± 2.59 mmHg to 13.38 ± 0.91 mmHg (P = 0.02). Pigment perfusion reduced the outflow facility from 0.27 ± 0.03 at baseline to 0.18 ± 0.02 at 48 hours (P < 0.001). This was partially reversed with RKI-1447. RKI-1447 caused no apparent histological changes in the micro- or macroscopic TM appearance. RKI-1447-treated primary TM cells showed significant disruption of the actin cytoskeleton both in the presence and absence of pigment (P < 0.001) but no effect on TM migration was observed. Pigment-treated TM cells exhibited a reduction in TM phagocytosis, which RKI-1447 reversed. Conclusion: RKI-1447 significantly reduces IOP by disrupting TM stress fibers and increasing TM phagocytosis. These features may make it useful for the treatment of secondary glaucomas with an increased phagocytic load.
ARTICLE | doi:10.20944/preprints202109.0277.v1
Subject: Life Sciences, Immunology Keywords: Huntington’s disease; transgenic Drosophila; immune response; phenoloxidase activity; phagocytosis; reactive oxygen species
Online: 16 September 2021 (11:05:34 CEST)
Huntington’s disease (HD) is a late-onset; progressive, dominantly inherited neurological disorder marked by an abnormal expansion of polyglutamine (poly Q) repeats in Huntingtin (HTT) protein. The pathological effects of mutant Huntingtin (mHTT) are not restricted to the nervous system but systemic abnormalities including immune dysregulation have been evidenced in clinical and experimental settings of HD. Indeed, mutant huntingtin (mHTT) is ubiquitously expressed and could induce cellular toxicity by directly acting on immune cells. However, it is still unclear if selective expression ofmHTT exon1 in neurons could induce immune responses and hemocyte function. In the present study, we intended to monitor perturbations in the hemocytes population and their physiological functions in Drosophila, caused by pan-neuronal expression of mHTT protein. We found that pan-neuronal expression of mHtt significantly alters crystal cells and plasmatocyte count in larvae and adults with disease progression. Interestingly, plasmatocytes isolated from diseased conditions exhibit a gradual decline in phagocytic activity ex vivo at progressive stages of the disease as compared to age-matched control groups. We also observed an increased production of reactive oxygen species (ROS) in plasmatocytes at advanced stages of the disease. In addition, diseased flies displayed elevated reactive oxygen species (ROS) in circulating plasmatocytes at the larval stage and in sessile plasmatocytes of hematopoietic pockets at of disease. All the parameters were monitored progressively, targeting the circulation at larvae stage and hematopoietic pockets in adults at different disease stages, and many alterations were documented in the early stage itself. These findings strongly implicate that neuronal expression of mHtt alone is sufficient to induce non-cell-autonomous immune dysregulation in vivo. Based on these findings, we propose that further insight into the mechanisms through which neuronal expression of mHtt might be inflicting the innate immune responses would facilitate therapeutic inventions aimed at amelioration of HD pathology and improving the quality of life of the patients.
ARTICLE | doi:10.20944/preprints201802.0026.v1
Subject: Medicine & Pharmacology, Ophthalmology Keywords: pig eye perfusion model; pigmentary glaucoma; ocular hypertension; ocular hypotension; phagocytosis; rho-kinase inhibitor
Online: 5 February 2018 (03:39:57 CET)
Objective: The Rho GTPase/Rho kinase pathway is an important target in glaucoma treatment. This study investigated the hypotensive effect of RKI-1447, a Rho kinase inhibitor developed for cancer treatment, in a porcine ex vivo pigmentary glaucoma model. Materials and Methods: Twenty-eight fresh porcine anterior chambers were perfused with pigment medium (1.67 × 107 pigment particles/mL) for 48 hours before being subjected to the RKI-1447 (n = 16) or the vehicle control (n = 12). Another twelve eyes with normal medium perfusion served as the control. The intraocular pressure (IOP) was recorded at two-minute intervals and the outflow facility was calculated. To investigate the intracellular mechanism of the IOP reduction, primary trabecular meshwork cells were exposed to RKI-1447 or the vehicle control and then analyzed for changes in cytoskeleton, motility, and phagocytosis. Results: Compared to the baseline, the perfusion of pigment caused a significant increase in IOP in the RKI-1447 group (P = 0.003) at 48 hours. Subsequent treatment with RKI-1447 significantly reduced IOP from 20.14 ± 2.59 mmHg to 13.38 ± 0.91 mmHg (P = 0.02). Pigment perfusion reduced the outflow facility from 0.27 ± 0.03 at baseline to 0.18 ± 0.02 at 48 hours (P < 0.001). This was partially reversed with RKI-1447. RKI-1447 exhibited no apparent changes in the micro- or macroscopic appearance, including histology. Primary TM cells exposed to RKI-1447 showed a significant disruption of the actin cytoskeleton both in the presence and absence of pigment exposure (P < 0.001) but no effect on TM migration was observed. Pigment-treated TM cells exhibited a reduction in TM phagocytosis, which RKI reversed. Conclusions: RKI-1447 is a novel ROCK inhibitor that significantly reduces IOP by disrupting TM stress fibers and increasing TM phagocytosis. These features may make it especially useful for the treatment of secondary glaucomas with an increased phagocytosis load but also for other open angle glaucomas.
ARTICLE | doi:10.20944/preprints201803.0219.v1
Subject: Medicine & Pharmacology, Ophthalmology Keywords: pigmentary glaucoma; pigment dispersion; intraocular pressure; trabecular meshwork; cytoskeleton; phagocytosis; gene expression microarray; signal pathway
Online: 27 March 2018 (05:22:15 CEST)
Pigment dispersion can lead to pigmentary glaucoma, a poorly understood condition of younger myopic eyes with fluctuating high intraocular pressure. It has been difficult to investigate its pathogenesis without a model similar to human eyes in size and behavior. Here we present a porcine ex vivo model that recreates several features of pigmentary glaucoma, including intraocular hypertension, accumulation of pigment in the trabecular meshwork, and declining phagocytosis. We found that trabecular meshwork cells regulate outflow, form actin stress fibers, and have a decreased phagocytic activity. Gene expression microarrays and a pathway analysis of TM monolayers as well as ex vivo anterior segment perfusion cultures indicated that RhoA plays a central role in regulating the cytoskeleton, motility, and phagocytosis in the trabecular meshwork, providing new insights and targets to investigate in pigmentary glaucoma.
ARTICLE | doi:10.20944/preprints201804.0007.v1
Subject: Medicine & Pharmacology, Ophthalmology Keywords: pigment dispersion syndrome; pigmentary glaucoma; trabecular meshwork; phagocytosis; migration; contraction; cytoskeleton; gene microarray; Rho signaling pathway
Online: 2 April 2018 (07:00:45 CEST)
Purpose: To investigate the effect of pigment dispersion on trabecular meshwork (TM) cells. Methods: Porcine TM cells from ab interno trabeculectomy specimens were exposed to pigment dispersion, then analyzed for changes in morphology, immunostaining, and ultrastructure. Their abilities to phagocytose, migrate, and contract were quantified. An expression microarray, using 23,937 probes, and a pathway analysis were performed. Results: TM cells readily phagocytosed pigment granules. Pigment induced stress fiber formation (pigment (P): 60.1 ± 0.3%, n = 10, control (C): 38.4 ± 2.5%, n = 11, P < 0.001) and contraction at 24 hours onward (P < 0.01). Phagocytosis declined (P: 68.7 ± 1.3%, C: 37.0 ± 1.1%, n = 3, P < 0.001) and migration was reduced after 6 hours (P: 28.0.1 ± 2.3, n = 12, C: 40.6 ± 3.3, n = 13, P < 0.01). Microarray analysis revealed that Rho, IGF-1, and TGFβ signaling cascades were central to these responses. Conclusions: TM cell exposure to pigment dispersion resulted in reduced phagocytosis and migration, as well as increased stress fiber formation and cell contraction. The Rho signaling pathway played a central and early role, suggesting that its inhibitors could be used as a specific intervention in treatment of pigmentary glaucoma.
ARTICLE | doi:10.20944/preprints202210.0180.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: C-reactive protein; STEMI; AMI; CRP apheresis; CMR; MRI; infarct size; inflammation; inflammatory mediators; ischaemia; hypoxia; phagocytosis
Online: 12 October 2022 (13:41:12 CEST)
In the multicenter, non-randomized, exploratory C-reactive protein (CRP) Apheresis in Myocardial Infarction (CAMI-1) study, CRP apheresis after ST-Elevation Myocardial Infarction (STEMI) significantly decreased blood CRP concentrations in humans. Cardiac damage was assessed by Cardiac Magnetic Resonance (CMR1) 3-9 d after onset of STEMI symptoms and quantified by myocardial infarct size (IS; %), left ventricular ejection fraction (LVEF; %), circumferential strain (CS) and longitudinal strain (LS) Compared with the control group (n=34), cardiac damage was significantly lower in the apheresis group (n=32). These findings suggested improved wound healing due to CRP apheresis already within few days after the STEMI event. In the current supplementary data analysis of CAMI-1, we have tested by a follow-up CMR (CMR2) after an average of 88 (65-177) d whether the effect of CRP apheresis is clinically maintained. After this time period wound healing in STEMI is considered complete. Whereas patients with low CRP production and a CRP gradient cut off of <0.6 mg/L/h in the hours after STEMI (9 of 32 patients in the CRP apheresis group) did not significantly benefit from CRP apheresis in CMR2, patients with high CRP production and a CRP gradient cut off of >0.6 mg/L/h (23 of 32 patients in the CRP apheresis group) showed significant treatment benefit. In the latter patients, CMR2 revealed a lower IS (-5.4%; p=0.05), a better LVEF (+6.4%; p=0.03), and an improved CS (-6.1%; p=0.005). No significant improvement, however, was observed for LS (-2.9%; p=0.1). These data suggest a sustained positive effect of CRP apheresis on the heart physiology in STEMI patients with high CRP production well beyond the period of its application. The data demonstrate the sustainability of the CRP removal from plasma which is associated with less scar tissue.
REVIEW | doi:10.20944/preprints202003.0288.v1
Subject: Life Sciences, Other Keywords: surveying microglia; amoeboid microglia; P2X receptors; P2Y receptors; P1 receptors; CD39; CD73; microglia-neuron cross talk; phagocytosis; microglial products; neuroinflammation
Online: 18 March 2020 (16:52:28 CET)
Microglial cells, the resident macrophages of the CNS, exist in a process-bearing, ramified/surveying phenotype under resting conditions. Upon activation by cell damaging factors they get transformed to an amoeboid phenotype releasing various cell products including pro-inflammatory cytokines, chemokines, proteases, reactive oxygen/nitrogen species and the excytotoxic ATP and glutamate. In addition, they engulf pathogenic bacteria or cell debris and phagocytose them. However, already resting/surveying microglia has a number of important physiological functions in the CNS; they e.g. shield small disruptions of the blood-brain barrier by their processes, dynamically interact with synaptic structures and clear surplus synapses during development. In neurodegenerative illnesses they aggravate the original disease by a microglia-based compulsory neuroinflammatory reaction. Therefore, the blockade of this reaction improves the outcome of Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, amyotrophic lateral sclerosis, etc. The function of microglia is regulated by a whole array of purinergic receptors classified as P2Y12, P2Y6, P2Y4, P2X4, P2X7, A2A, A3, and being targets for endogenous ATP, ADP, or adenosine. ATP is sequentially degraded by the ecto-nucleotidases and 5’-nucleotidase enzymes to the weak adenosine agonist inosine as an end-product. The appropriate selective agonists/antagonists for purinergic receptors as well as the respective enzyme inhibitors may profoundly interfere with microglial functions and reconstitute the homeostasis of the CNS disturbed by neuroinflammation.