Month: November 2020

Based on the human genome sequencing, 60% of the 800 GPCRs that have been identified belong to the so-called olfactory or sensory receptors. The remaining 40% are classified in five main families under the GRAFS system. In line with their pivotal role in a number of physiological processes, GPCRs have been found dysregulated in several human pathologies including cardiovascular and gastrointestinal diseases, nervous and immune disorders and cancers. As a matter of fact, nearly half of the drugs marketed by pharmaceutical industries targets GPCRs. In this context, highly specific anti-GPCR antibodies may be particularly helpful to better define anatomical localization as well as biochemical and biological properties of the receptors targeted for therapy. Antibodies may be used to reveal GPCR expression on living cells or on membrane extracts as well as in situ on fixed tissue sections. Specific antibodies may be helpful to purify receptors, characterize receptor dimers, identify receptor-associated protein partners, stabilize GPCR for crystallography, study ligand-binding kinetics and conformation states. In the absence of specific ligands, anti-GPCR antibodies are a valuable alternative for studying orphan receptors. Moreover, development of antibodies against GPCRs such as adhesion receptors, for which conventional small molecule drug discovery methods are often unsuccessful, offers a promising alternative for pharmaceutical industries. Approximately 80 GPCRs, Axitinib notably those involved in cancer, inflammatory or metabolic disorders have been recently identified as suitable targets for antibody-based therapy. Anti-GPCR antibodies, that do not cross the blood-brain barrier because of their high molecular weight, could also be instrumental in only targeting GPCRs expressed in periphery. Thus, agonistic antibodies with no central nervous system-mediated side effects might be used to relieve from inflammatory pain by stimulating opioid receptors expressed on sensory neurons. Specific antibodies against a variety of antigens including GPCRs can be developed using phage display technology, but the common method to produce antibody probes consists in immunizing animals against target proteins. As a matter of fact, most of the available anti-GPCR antibodies are polyclonal serum IgG generated by immunizing animals with synthetic peptides corresponding to amino-acid sequences located within the amino –terminal or carboxy -terminal domains or within extra or intra-cellular loops of the receptors. However, as recently reported for a number of GPCRs including opioid receptors, commercial available polyclonal antibodies often display non-specific reactivities and/or cross-reactivities with other plasma membrane proteins thus making it difficult to clearly distinguish a specific antibody-receptor binding. In most of the cases, the staining patterns of anti-GPCR peptide antibodies are similar in wild-type and GPCR-deficient mice as assessed by immunohistochemistry or western-blotting. A recent study, comparing the specificity of a number of commercial anti-opioid receptor antibodies, has shown that all the antibodies revealed numerous non-specific bands including a band at the expected molecular weight in both wild-type CHO cells and GPCR-expressing CHO cells as assessed by western-blotting. Given the lack of specificity of anti-GPCR peptide antibodies with receptors in native conformation.

Despite the strong evidence of Th17 cells modulating host responses to various forms of candidiasis, no role of the Th17 pathway of immunity could be demonstrated at any level for fungal burden, PMN migration and S100 alarmin production in the vagina during experimental vaginal candidiasis. All Masitinib 790299-79-5 strains of mice deficient in cytokines of Th17-lineage were equally susceptible to vaginal colonization with Candida compared to wild-type mice. Likewise, all animals were able to elicit a robust vaginal PMN response and S100 induction/secretion by vaginal epithelium following inoculation. Although these findings were unexpected based on the strong role of the Th17 response in PMN migration and induction of S100 alarmins, the lack of roles for the Th17 pathway may be explained two-fold. First, previous studies showed that vaginal epithelial cells are a primary source of S100 alarmins following vaginal inoculation with Candida where early Candida adherence to vaginal epithelium within the first 24 h is a critical event in initiating the PMN response. Thus, the S100 alarmin induction during vaginal infection is mediated exclusively by a direct interaction between epithelial cells and Candida. Our current data extends this to exclude any role for Th17 in the process. Second, while host responses by CD4+ T cells are generally required for protection against mucosal candidiasis, no role has been shown for either local or systemic CD4+ T cells against VVC. The lack of a protective role for CD4+ T cells is further supported by accumulating evidence of immunomodulatory mechanisms towards adaptive responses. Hence, it may not be surprising that this also includes Th17-type responses as well as Th22 cells. Of note, there is the possibility that IL-17 and IL-22 are produced by other cellular sources. These may include cd T cells and other innate lymphoid cells in the vaginal mucosa that may act on epithelial cells and contribute to the induction of S100 alarmin-mediated inflammation during vaginal infection. However, while IL-17 and IL-22 were increased moderately in wild-type mice following inoculation, both cytokines were virtually negligible in IL-23p192/2 mice, suggesting that the cytokines by these other cell sources is minimal at best. Despite strong evidence shown here against a role for Th17 cells and the fact that Th17 cells are known to be the major producer of IL-17 and IL-22, we recognize that IL-22 alone still may be a driving force in the PMN response and that IL-22 derived from innate immune cells could initiate the S100 response in vaginal epithelial cells. However, our results from IL-222/2 mice showing elevated vaginal S100 alarmins and PMN infiltration in response to Candida at equivalent levels to wild-type mice reduces the possibility of IL-22 being a primary cytokine in the S100 response. Furthermore, the epithelial cell S100 alarmin response occurs concomitantly with the exclusive presence of PMNs within 48 h post-inoculation. Thus, it is unlikely that contributions of S100 alarmins are made by other nonresident innate or adaptive cells. However, we recognize that other resident innate cells could contribute at low levels. Once the S100 alarmins and PMNs are present, the inflammatory process is in place and continues for a considerable time. Hence, the role for the Th17 pathway in this model would likely be evident early as much as later in the infection. Taken together, we hypothesize that the vaginal S100 induction and accompanied PMN response are initiated.

Fly mutants of the inositol 1,4,5 trisphosphate receptor gene, itpr, are unable to evoke air-puff stimulated flight, even though physiological responses on stimulation of the giant-fiber pathway remain unaltered. Previous work has demonstrated that expression of an itpr+ cDNA in aminergic neurons rescued loss of flight in itpr mutants close to wildtype levels and blocking of synaptic activity in aminergic neurons by tetanus toxin expression reduced flight to 45%. Moreover, an adult requirement for the serotonergic component of aminergic neurons was indicated, since a flight deficit of 33% was observed in wild-type adult flies fed for 5 days with a serotonin synthesis inhibitor, parachlorophenylalanine. Thus a role for synaptic activity in aminergic neurons was indicated, with a possible requirement for serotonin both during AMN107 clinical trial development and in adult flight. More recently, it was shown that intracellular Ca2+ signaling through IP3R and storeoperated Ca2+ entry in neurons are important for air-puff induced flight, suggesting that aminergic neuron function in Drosophila flight might require IP3R mediated Ca2+ signals. In this study, we have studied the effect of blocking synaptic function and reduced intracellular Ca2+ signaling specifically in serotonergic neurons, on air-puff stimulated flight. It is known that the insect flight circuit is formed during pupal development. Therefore, the effect of blocking synaptic activity in serotonergic neurons during pupal development and in adults was assessed. We show that blocking synaptic activity in serotonergic neurons either during flight circuit development or in adults reduces air-puff induced flight significantly. Our data suggest that synaptic activity affects the number of flight modulating serotonergic neurons in the second thoracic segment, but modulation of flight by these neurons does not require the IP3R or SOCE. In locusts, serotonin acts on the fast extensor and flexor tibiae motor neurons and this results in potentiation of synaptic transmission between these neurons, thereby modulating their neuronal properties and synaptic strengths. The partial flight deficit observed in Drosophila by synaptic inhibition of serotonergic neurons could be due to loss or reduction in similar modulatory effects of serotonin on as yet unidentified neurons of the flight circuit. Studies in locusts have also shown that a flight central pattern generator residing in the thorax, drives the motoneurons and maintains the phase relationship among the motor units of each muscle. Biogenic amines, such as octopamine and tyramine have been shown to modulate the flight CPG in locusts, Manduca and other moths. Though precise components of flight CPG are unknown, it is thought to be activated by a muscarinic cholinergic mechanism in locusts. Because octopaminergic modulation of Drosophila flight CPG has already been shown, it is likely that the flight CPG is modulated by multiple neuromodulators including serotonin. Our data suggest that the function of these neuromodulators can be compensated by each other. Temporal blocking of synaptic function in TRH neurons by expressing a temperature sensitive dynamin transgene, UASShits demonstrated a greater requirement for synaptic activity in serotonergic neurons during pupal development, followed by a reduced requirement in adults. In Drosophila, components of indirect flight motoneurons undergo dendritic and axonal remodeling during early pupal stages.