Molecular Receptors Research Articles

Time-related survival prediction in molecular subtypes of breast cancer using time-to-event deep-learning-based models.

Breast cancer (BC) survival prediction can be a helpful tool for identifying important factors selecting the effective treatment reducing mortality rates. This study aims to predict the time-related survival probability of BC patients in different molecular subtypes over 30 years of follow-up. This study retrospectively analyzed 3580 patients diagnosed with invasive breast cancer (BC) from 1991 to 2021 in the Cancer Research Center of Shahid Beheshti University of Medical Science. The dataset contained 18 predictor variables and two dependent variables, which referred to the survival status of patients and the time patients survived from diagnosis. Feature importance was performed using the random forest algorithm to identify significant prognostic factors. Time-to-event deep-learning-based models, including Nnet-survival, DeepHit, DeepSurve, NMLTR and Cox-time, were developed using a grid search approach with all variables initially and then with only the most important variables selected from feature importance. The performance metrics used to determine the best-performing model were C-index and IBS. Additionally, the dataset was clustered based on molecular receptor status (i.e., luminal A, luminal B, HER2-enriched, and triple-negative), and the best-performing prediction model was used to estimate survival probability for each molecular subtype. The random forest method identified tumor state, age at diagnosis, and lymph node status as the best subset of variables for predicting breast cancer (BC) survival probabilities. All models yielded very close performance, with Nnet-survival (C-index=0.77, IBS=0.13) slightly higher using all 18 variables or the three most important variables. The results showed that the Luminal A had the highest predicted BC survival probabilities, while triple-negative and HER2-enriched had the lowest predicted survival probabilities over time. Additionally, the luminal B subtype followed a similar trend as luminal A for the first five years, after which the predicted survival probability decreased steadily in 10- and 15-year intervals. This study provides valuable insight into the survival probability of patients based on their molecular receptor status, particularly for HER2-positive patients. This information can be used by healthcare providers to make informed decisions regarding the appropriateness of medical interventions for high-risk patients. Future clinical trials should further explore the response of different molecular subtypes to treatment in order to optimize the efficacy of breast cancer treatments.

Structural Insights into Molecular Recognition and Receptor Activation in Chemokine-Chemokine Receptor Complexes.

The chemokine system is a key player in the functioning of the immune system and a sought-after target for drug candidates. The number of experimental structures of chemokines in complex with chemokine receptors has increased rapidly over the past few years, providing essential information for rational development of chemokine receptor ligands. Here, we perform a comparative analysis of all chemokine-chemokine receptor structures, with the aim of characterizing the molecular recognition processes and highlighting the relationships between chemokine structures and functional processes. The structures show conserved interaction patterns between the chemokine core and the receptor N-terminus, while interactions near ECL2 display subfamily-specific features. Detailed analyses of the interactions of the chemokine N-terminal domain in the 7TM cavities reveal activation mechanisms for CCR5, CCR2, and CXCR2 and a mechanism for biased agonism in CCR1.

Molecular Recognition in Confined Space Elucidated with DNA Nanopores and Single-Molecule Force Microscopy.

The binding of ligands to receptors within a nanoscale small space is relevant in biology, biosensing, and affinity filtration. Binding in confinement can be studied with biological systems but under the limitation that essential parameters cannot be easily controlled including receptor type and position within the confinement and its dimensions. Here we study molecular recognition with a synthetic confined nanopore with controllable pore dimension and molecular DNA receptors at different depth positions within the channel. Binding of a complementary DNA strand is studied at the single-molecule level with atomic force microscopy. Following the analysis, kinetic association rates are lower for receptors positioned deeper inside the pore lumen while dissociation is faster and requires less force. The phenomena are explained by the steric constraints on molecular interactions in confinement. Our study is the first to explore recognition in DNA nanostructures with atomic force microscopy and lays out new tools to further quantify the effect of nanoconfinement on molecular interactions.

Exploration of Indolo[3,2c]isoquinoline derived triazoles as potential antimicrobial and DNA cleavage agents: Synthesis, DFT calculations, and molecular modeling studies

Indole and its derivatives are well-known assorted motif in drug design and development. We here in reporting synthesis of new 9-chloro-1-(4-substituted phenyl)-12H-indolo[2,3-c][1,2,4]triazolo[3,4-a]isoquinolines 7 (a-h). Structures of the newly synthesized compounds were confirmed by making use of spectroscopic techniques like IR, NMR and Mass. The DFT calculations were taken for the selected molecules using CAM-B3LYP hybrid functional with a 6–31 + g(d) all-electron basis set using the Gaussian 09 package. The drug-likeness predictions were described for the synthesized derivatives. The In vitro antimicrobial and DNA cleavage activities were reported for all compounds 7 (a-h). The compounds 7a, 7b, and 7h showed excellent microbial inhibition and DNA cleavage activity as compared to standard drugs. Furthermore, the docking studies for the newly synthesized molecules were carried out by Auto dock software with two molecular targets Epidermal Growth Factor Receptor tyrosine kinase (1 M17) and C-kit Tyrosine Kinase (1 T46) exhibited better binding affinity of all synthesized compounds. In addition, the docking results were observed to be in full agreement with the in vitro DNA cleavage assay suggesting the potential of synthesized metal complexes in biological applications. Lastly, the protein stability, fluctuations of APO-Protein, and protein–ligand complexes were investigated through Molecular Dynamics (MD) simulations studies using Desmond Maestro 11.3 and potential lead molecules were identified.

Transcriptome Sequencing of CeRNA Network Constructing in Status Epilepticus Mice Treated by Low-Frequency Repetitive Transcranial Magnetic Stimulation

It is shown that great progress was recently made in the treatment of repetitive transcranial magnetic stimulation (rTMS) for neurological and psychiatric diseases. This study aimed to address how rTMS exerted it therapeutic effects by regulating competitive endogenous RNAs (ceRNAs) of lncRNA-miRNA-mRNA. The distinction of lncRNA, miRNA and mRNA expression in male status epilepticus (SE) mice treated by two different ways, low-frequency rTMS (LF-rTMS) vs. sham rTMS, was analyzed by high-throughput sequencing. The Gene Ontology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were carried out. Gene–Gene Cross Linkage Network was established; pivotal genes were screened out. qRT-PCR was used to verify gene–gene interactions. Our results showed that there were 1615 lncRNAs, 510 mRNAs, and 17 miRNAs differentially which were expressed between the LF-rTMS group and the sham rTMS group. The expression difference of these lncRNAs, mRNAs, and miRNAs by microarray detection were consistent with the results by qPCR. GO functional enrichment showed that immune-associated molecular mechanisms, biological processes, and GABA-A receptor activity played a role in SE mice treated with LF-rTMS. KEGG pathway enrichment analysis revealed that differentially expressed genes were correlated to T cell receptor signaling pathway, primary immune deficiency and Th17 cell differentiation signaling pathway. Gene–gene cross linkage network was established on the basis of Pearson’s correlation coefficient and miRNA. In conclusion, LF-rTMS alleviates SE through regulating the GABA-A receptor activity transmission, improving immune functions, and biological processes, suggesting the underlying ceRNA molecular mechanisms of LF-rTMS treatment for epilepsy.

PENAMBATAN MOLEKUL SIANIDIN Ipomoea batatas L. SEBAGAI INHIBITOR HUMAN EPIDERMAL RECEPTOR 2 (HER-2) PADA KANKER PAYUDARA

HER-2 (Human Epidermal Receptor 2) is a receptor on the cell surface that affects cell proliferation, this receptor support controls healthy cell growth,divide and repair cells when they are damaged. When HER-2 had overexpressed will not controlled cancer cell division. Overexpressed HER-2 could inhibited with cyanidine compound flavonoid derivatives from Ipomoea batatas L. (purple sweet potato). This study aim to measured potential of Ipomoea batatas L. cyanidin compounds in inhibited overexpressed HER-2 using computational chemistry methods specifically is molecular docking. Stages of molecular docking receptor HER-2 is ligand set up with drew structure cyanidine with Marvin Sketch then optimized by Autodock Tools and Discovery Studio, lapatinib as a comparison ligand downloaded on PubChem website. HER-2 (3PP0) prepared with downloaded on Protein Data Bank website then optimized by Autodock Tools. Molecular Docking validated with docked protein target with native ligand by PyMOL to secured RMSD (root mean square deviation). Protein Targeted HER-2 docked with test ligand cyanidine, lapatinib, and native ligand by Autodock VINA, analysed energy bond and amino acid residue interactions by LigPlot+. Cyanidine had potency inhibitor of receptor HER-2 overexpressed from docked is had bound energy -7.1 ccal/mol up to -8.6 ccal/mol wich is also had amino acid residue interactions Met 801 equal to native ligand

Aqueous Three-Component Self-Assembly of a Pseudo[1]rotaxane Using Hydrazone Bonds.

We present herein the synthesis of a new polycationic pseudo[1]rotaxane, self-assembled in excellent yield through hydrazone bonds in aqueous media of three different aldehyde and hydrazine building blocks. A thermodynamically controlled process has been studied sequentially by analyzing the [1 + 1] reaction of a bisaldehyde and a trishydrazine leading to the macrocyclic part of the system, the ability of this species to act as a molecular receptor, the conversion of a hydrazine-pending cyclophane into the pseudo[1]rotaxane and, lastly, the one-pot [1 + 1 + 1] condensation process. The latter was found to smoothly produce the target molecule through an integrative social self-sorting process, a species that was found to behave in water as a discrete self-inclusion complex below 2.5 mM concentration and to form supramolecular aggregates in the 2.5-70 mM range. Furthermore, we demonstrate how the abnormal kinetic stability of the hydrazone bonds on the macrocycle annulus can be advantageously used for the conversion of the obtained pseudo[1]rotaxane into other exo-functionalized macrocyclic species.

Dynamic Approach to Synthetic Lectin for Glucose with Boosted Binding Affinity through C-H Hydrogen Bonds.

A biomimetic receptor for glucose has been developed with high affinity and selectivity. The receptor was efficiently synthesized in three steps through dynamic imine chemistry followed by imine-to-amide oxidation. The receptor features two parallel durene panels, forming a hydrophobic pocket for [CH⋅⋅⋅π] interactions, and two pyridinium residues directing four amide bonds towards the pocket. These pyridinium residues not only improve solubility but also provide polarized C-H bonds for hydrogen bonding. Experimental data and DFT calculations show that these polarized C-H bonds significantly enhance substrate binding. These findings demonstrate the power of dynamic covalent chemistry for creating molecular receptors and using polarized C-H bonds for boosted carbohydrate recognition in water, providing a foundation for developing glucose-responsive materials and sensors.

Heptagon-Containing Nanographene Embedded into [10]Cycloparaphenylene.

We report the synthesis and characterization of a novel type of nanohoop, consisting of a cycloparaphenylene derivative incorporating a curved heptagon-containing p-extended polycyclic aromatic hydrocarbon unit. We demonstrate that this new macrocycle behaves as a supramolecular receptor of curved p-systems such as fullerenes C60 and C70, with remarkably large binding constants (ca. 107 M-1), as estimated by fluorescence measurements. Nanosecond and femtosecond spectroscopic analysis show that these host-guest complexes are capable of quasi-instantaneous charge separation upon photoexcitation, due to the ultrafast charge transfer from the macrocycle to the complexed fullerene. These results demonstrate saddle-shaped polycyclic aromatic hydrocarbons (PAHs) with dibenzocycloheptatrienone motifs as structural components for new macrocycles displaying molecular receptor abilities and versatile photochemical responses with promising electron-donor properties in host-guest complexes.

Heptagon‐Containing Nanographene Embedded into [10]Cycloparaphenylene

AbstractWe report the synthesis and characterization of a novel type of nanohoop, consisting of a cycloparaphenylene derivative incorporating a curved heptagon‐containing π‐extended polycyclic aromatic hydrocarbon (PAH) unit. We demonstrate that this new macrocycle behaves as a supramolecular receptor of curved π‐systems such as fullerenes C60 and C70, with remarkably large binding constants (ca. 107 M−1), as estimated by fluorescence measurements. Nanosecond and femtosecond spectroscopic analysis show that these host‐guest complexes are capable of quasi‐instantaneous charge separation upon photoexcitation, due to the ultrafast charge transfer from the macrocycle to the complexed fullerene. These results demonstrate saddle‐shaped PAHs with dibenzocycloheptatrienone motifs as structural components for new macrocycles displaying molecular receptor abilities and versatile photochemical responses with promising electron‐donor properties in host‐guest complexes.

Research of the Expression of IL-13 Receptors and IL-13R Genes in the Bronch of Rats with Ovalbumin-Induced Bronchial Asthma

This article presents the results of studies of the levels of expression of the IL13R gene and the levels of expression of the molecular IL13R in the bronchi of control rats and rats with ovalbumin-induced asthma. The choice of these receptors is due to the great importance of these structures in the pathogenesis of allergic bronchial asthma. Biological materials of 64 Wistar rats were studied using real-time PCR and immunohistochemical methods. As a result of the studies, it was found that under conditions of asthma development in the tissues of the bronchi of rats, a pronounced expression of the IL13R genes, a significant expression of the molecular receptor for interleukin-13, occurs. In bronchi with an intramural ganglion (bifurcation zone), the level of IL13R gene expression and the level of expression of the IL13R molecular receptor were significantly higher than in tracheal samples without ganglia. Sodium cromoglycate, administered to rats 5 hours after the last inhalation of ovalbumin, led to a decrease in the mRNA content in the bronchi of animals compared to animals that did not receive mast cell stabilizer treatment.

Unsymmetrically bi-functionalized 1,1′-ferrocenyl bi-hydrazone and hydrazone-cyanovinyl molecules as fluorescent “on–off” sensor: Synthesis, cytotoxicity and cancer cell imaging behavior

Unsymmetrically bi-functionalized ferrocenyl compounds are significant class of multifunctional molecule having unique structural features, varied conformational orientations, tunable electrochemical behavior and wide functional prospects. Strategic design of these unsymmetrical derivatives involving multifunctional components containing sandwich based electroactive fragment, heterocyclic moieties and a highly emissive photo-responsive unit can create flexible, biocompatible fluorescent single molecule - probe for sensor and signaling based molecular devices. Therefore, synthesis of fluorophoric 1,1′-unsymmetrical bi-functionalized ferrocenyl molecular receptor have been carried out using two different types of solid supported condensation reactions, one using Schiff base condensation reaction to link hydrazone based heterocyclic moieties and the other involving a Knoevenagel condensation to link cyano-vinyl based donor–acceptor system, to obtain 1,1′-ferrocenyl rhodaminyl-pyridyl hydrazones and 1,1′-ferrocenyl hydrazone-cyanovinylester derivatives. The unsymmetrical nature of the molecules has been established by single crystal diffraction study and explored for their fluorescence and electrochemical based signaling and sensing behavior of metal cations in solution and subcellular level. The study showed significant intracellular metal recognition and imaging characteristics for their potential in applications related to bioimaging of heavy metal ions. DFT study revealed distinct interaction of the metal ion leading to a change in structural conformation due to the rotational flexibility within the ferrocenyl axis. Molecules were also explored for their cytotoxic behavior and protein binding interaction to understand their biological potential.

Microglial activating transcription factor 3 upregulation: An indirect target to attenuate inflammation in the nervous system.

Activating Transcription Factor 3 (ATF3) is upregulated in reaction to several cellular stressors found in a wide range of pathological conditions to coordinate a transcriptional response. ATF3 was first implicated in the transcriptional reaction to axotomy when its massive upregulation was measured in sensory and motor neuron cell bodies following peripheral nerve injury. It has since been shown to be critical for successful axon regeneration in the peripheral nervous system and a promising target to mitigate regenerative failure in the central nervous system. However, much of the research to date has focused on ATF3's function in neurons, leaving the expression, function, and therapeutic potential of ATF3 in glia largely unexplored. In the immunology literature ATF3 is seen as a master regulator of the innate immune system. Specifically, in macrophages following pathogen or damage associated molecular pattern receptor activation and subsequent cytokine release, ATF3 upregulation abrogates the inflammatory response. Importantly, ATF3 upregulation is not exclusively due to cellular stress exposure but has been achieved by the administration of several small molecules. In the central nervous system, microglia represent the resident macrophage population and are therefore of immediate interest with respect to ATF3 induction. It is our perspective that the potential of inducing ATF3 expression to dampen inflammatory microglial phenotype represents an unexplored therapeutic target and may have synergistic benefits when paired with concomitant neuronal ATF3 upregulation. This would be of particular benefit in pathologies that involve both detrimental inflammation and neuronal damage including spinal cord injury, multiple sclerosis, and stroke.

Digital nanoreactors to control absolute stoichiometry and spatiotemporal behavior of DNA receptors within lipid bilayers

Interactions between membrane proteins are essential for cell survival but are often poorly understood. Even the biologically functional ratio of components within a multi-subunit membrane complex—the native stoichiometry—is difficult to establish. Here we demonstrate digital nanoreactors that can control interactions between lipid-bound molecular receptors along three key dimensions: stoichiometric, spatial, and temporal. Each nanoreactor is based on a DNA origami ring, which both templates the synthesis of a liposome and provides tethering sites for DNA-based receptors (modelling membrane proteins). Receptors are released into the liposomal membrane using strand displacement and a DNA logic gate measures receptor heterodimer formation. High-efficiency tethering of receptors enables the kinetics of receptors in 1:1 and 2:2 absolute stoichiometries to be observed by bulk fluorescence, which in principle is generalizable to any ratio. Similar single-molecule-in-bulk experiments using DNA-linked membrane proteins could determine native stoichiometry and the kinetics of membrane protein interactions for applications ranging from signalling research to drug discovery.

Perspective of molecular imaging and peptide receptor radionuclide therapy in pancreatic neuroendocrine tumors: where do we stand?

The clinical use of nuclear medicine imaging and therapy in pancreatic neuroendocrine tumors has been greatly strengthened since the approval of 68Ga-DOTATATE and 177Lu-DOTATATE. However, many aspects are still under discussion. In this 2-part article, we aim to collect and discuss current evidence of molecular imaging and peptide receptor radionuclide therapy (PRRT) in pancreatic neuroendocrine tumor. In the first part, we will address some critical aspects of 68Ga-SSAs imaging, including diagnostic efficacy, recurrence detection and follow-up, patient selection for PRRT, and pitfalls in image interpretation. Besides, we will also briefly discuss the role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography, special imaging strategy in regard to insulinoma, and the status of radiolabeled somatostatin receptor antagonist. In the second part, we aim to review the current evidence of PRRT in pancreatic neuroendocrine tumor, focusing on efficacy and safety in particular. We will also introduce the recent development of PRRT, including PRRT in high-grade neuroendocrine neoplasms, retreatment PRRT, upfront PRRT, PRRT in the setting of neoadjuvant therapy and conversion therapy, combination therapies with PRRT, PRRT with αradionuclides, and PRRT with antagonists.

Effects of brain-derived neurotrophic factor and adeno-associated viral vector on morphine-induced condition through target concentration changes in the ventral tegmental area and nucleus accumbens

Morphine remains the standard analgesic for severe pain. However, the clinical use of morphine is limited by the innate tendency of opiates to become addictive. Brain-derived neurotrophic factor (BDNF) is a growth factor that is protective against many mental disorders. This study aimed to evaluate the protective function of BDNF on morphine addiction based on the behavioural sensitisation (BS) model and assess potential changes in downstream molecular tropomyosin-related kinase receptor B (TrkB) and cyclic adenosine monophosphate response element binding protein (CREB) expression caused by overexpression of BDNF. We divided 64 male C57BL/6 J mice into saline, morphine, morphine plus adeno-associated viral vector (AAV), and morphine plus BDNF groups. After administering the treatments, behavioural tests were conducted during the development and expression phases of BS, followed by a western blot analysis. All data were analysed by one- or two-way analysis of variance. The overexpression of BDNF in the ventral tegmental area (VTA) caused by BDNF-AAV injection decreased the total distance of locomotion in mice who underwent morphine-induced BS and increased the concentrations of BDNF, TrkB, and CREB in the VTA and nucleus accumbens (NAc). BDNF exerts protective effects against morphine-induced BS by altering target gene expression in the VTA and NAc.

Pafolacianine for intraoperative molecular imaging of cancer in the lung: The ELUCIDATE trial

ObjectiveThe study objective was to determine the clinical utility of pafolacianine, a folate receptor–targeted fluorescent agent, in revealing by intraoperative molecular imaging folate receptor α positive cancers in the lung and narrow surgical margins that may otherwise be undetected with conventional visualization. MethodsIn this Phase 3, 12-center trial, 112 patients with suspected or biopsy-confirmed cancer in the lung scheduled for sublobar pulmonary resection were administered intravenous pafolacianine within 24 hours before surgery. Participants were randomly assigned to surgery with or without intraoperative molecular imaging (10:1 ratio). The primary end point was the proportion of participants with a clinically significant event, reflecting a meaningful change in the surgical operation. ResultsNo drug-related serious adverse events occurred. One or more clinically significant event occurred in 53% of evaluated participants compared with a prespecified limit of 10% (P < .0001). In 38 participants, at least 1 event was a margin 10 mm or less from the resected primary nodule (38%, 95% confidence interval, 28.5-48.3), 32 being confirmed by histopathology. In 19 subjects (19%, 95% confidence interval, 11.8-28.1), intraoperative molecular imaging located the primary nodule that the surgeon could not locate with white light and palpation. Intraoperative molecular imaging revealed 10 occult synchronous malignant lesions in 8 subjects (8%, 95% confidence interval, 3.5-15.2) undetected using white light. Most (73%) intraoperative molecular imaging–discovered synchronous malignant lesions were outside the planned resection field. A change in the overall scope of surgical procedure occurred for 29 of the subjects (22 increase, 7 decrease). ConclusionsIntraoperative molecular imaging with pafolacianine improves surgical outcomes by identifying occult tumors and close surgical margins.

Diagnostic utility of the lymphoid screening tube supplemented with TRBC1 for the assessment of T-cell clonality.

Flow cytometric panels for the investigation of lymphoproliferative disorders, such as the EuroFlow Lymphoid Screening Tube (LST), often fail to demonstrate T-cell clonality, as a suitable clonality marker was unavailable until recently. Aim of this study was to evaluate the added value of supplementing TRBC1, a flow cytometric T-cell clonality marker, to the LST. Flow cytometric analysis was performed on 830 routine samples referred to our lab for suspicion of hematological malignancy. T-cells with monotypic TRBC1-expression were additionally characterized with a 12-color T-cell tube and molecular T-cell receptor gamma gene rearrangement (TRG). LST analysis revealed 97 (11.7%) samples with the presence of a monotypic T-cell population according to TRBC1, including 21 (2.5%) "high-count" (≥500 cells/μL blood or ≥15% of lymphocytes) and 76 (9.2%) "low-count" (<500 cells/μL blood or <15% of lymphocytes) populations. Clinical symptoms indicative for T-CLPD could be correlated to 11/21 "high-count" and 17/76 "low-count" monotypic T-cell populations. Molecular TRG analysis demonstrated a monoclonal result in 76% (16/21) of "high-count" samples and in 64% (42/66; 10 samples not tested) of "low-count" samples, but also in 9/20 samples with polytypic TRBC1 results. Analysis of an LST tube supplemented with TRBC1 led to the detection of a high number of monotypic T-cell populations. The detection of numerous small monotypic T-cell populations raises the question of their clinical significance. A possible flowchart for assessment of these populations, based on the available literature, is proposed. Molecular TRG analysis is complementary and cannot be omitted from T-cell clonality assessment.

Perfluoroethylcyclohexane sulphonate, an emerging perfluoroalkyl substance, disrupts mitochondrial membranes and the expression of key molecular targets in vitro

Perfluoroethylcyclohexane sulphonate (PFECHS) is an emerging, replacement perfluoroalkyl substance (PFAS) with little information available on the toxic effects or potencies with which to characterize its potential impacts on aquatic environments. This study aimed to characterize effects of PFECHS using in vitro systems, including rainbow trout liver cells (RTL-W1 cell line) and lymphocytes separated from whole blood. It was determined that exposure to PFECHS caused minor acute toxic effects for most endpoints and that little PFECHS was concentrated into cells with a mean in vitro bioconcentration factor of 81 ± 25 L/kg. However, PFECHS was observed to affect the mitochondrial membrane and key molecular receptors, such as the peroxisome proliferator receptor, cytochrome p450-dependent monooxygenases, and receptors involved in oxidative stress. Also, glutathione-S-transferase was significantly down-regulated at a near environmentally relevant exposure concentration of 400 ng/L. These results are the first to report bioconcentration of PFECHS, as well as its effects on the peroxisome proliferator and glutathione-S-transferase receptors, suggesting that even with little bioconcentration, PFECHS has potential to cause adverse effects.

Impact of Selected Bacterial and Viral Toll-like Receptor Agonists on the Phenotype and Function of Camel Blood Neutrophils.

Innate recognition of pathogens depends on the interaction between microbial structures known as pathogen-associated molecular patterns (PAMPs) and pattern recognition receptors (PRRs) in host cells. Toll-like receptors (TLR) are among the most important PRRs being expressed on and in a wide range of immune cell types. Studies on the interaction mechanisms between different pathogen species and the immune system of the dromedary camel are still scarce. The present study aimed to investigate the immunomodulatory effect of synthetic bacterial and viral TLR ligands on some phenotypic properties and selected functions of neutrophils purified from dromedary camel blood. Neutrophils were separated from camel blood (n = five animals) and were stimulated in vitro with the TLR ligands LPS, Pam3CSK4, R848 (Resiquimod), and Poly IC or were left without stimulation. Stimulation with the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) was used as a positive control stimulation. Shape change, phagocytosis activity, ROS production, the expression of cell surface markers, and cell vitality were compared between stimulated and non-stimulated cells. With exception of the TLR3 agonist Poly IC, all TLR ligands used showed the potential to stimulate camel neutrophils resulting in increased cell size and the upregulation of CD18 and CD14 on their surface. Similarly, the phagocytosis activity of camel neutrophils was significantly improved after priming with all TLR ligands, except Poly IC, which, in contrast, resulted in a reduced percentage of phagocytosis-positive cells. In contrast to stimulation with PMA, which induced a significant ROS production in camel neutrophils, none of the TLR ligands used stimulated ROS generation in neutrophils. Only stimulation with Pam3CSK4 increased the expression of MHCII molecules on camel neutrophils, resulting in an expanded MHCIIhigh fraction within camel neutrophils. Our study indicates selective immunomodulating effects of TLR agonists on purified camel neutrophils without affecting their vitality.