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Therapies to Prevent or Inhibit Chemokine Receptor Expression
Published in Thomas R. O’Brien, Chemokine Receptors and AIDS, 2019
J. Scott Cairns, M. Patricia D’Souza
Although CXCR4 and CCR5 serve as the major coreceptors for HIV, other chemokine receptors, such as CCR2b (9), CCR3 (9,10), CCR8 (21), and CX3CR1 (22), as well as orphan receptors for which the ligand is unknown, including Apj (23), STRL33 (BONZO) (24,25), and BOB (GPR15) (24), can also function as fusion cofactors for HIV entry in laboratory assays. Clearly, proteins belonging to this family have biochemical properties that promote HIV membrane fusion. However, most of the above mentioned secondary coreceptors are not very efficient and function only with certain strains of HIV-1, HIV-2 or SIV. Their relevance in transmission and pathogenesis in vivo is unknown.
Lymphocyte trafficking from inductive sites to effector sites
Published in Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald, Principles of Mucosal Immunology, 2020
Valerie Verhasselt, William Agace, Oliver Pabst, Andrew Stagg
One of the best-characterized examples of a common homing receptor usage is that of CCR10 for the localization of IgA plasma cells to mucosal tissues. Epithelial cells at a range of mucosal sites, including the intestinal tract, trachea, and salivary and mammary glands, constitutively express the CCR10 ligand, CCL28, and IgA-positive plasma cells at many of these sites have been shown to express CCR10. Furthermore, CCR10 has a redundant role (together with CCR9) in mediating IgA plasmablast recruitment to the small intestine, but has a nonredundant role in the recruitment of IgA plasmablasts into the lactating mammary gland and thus the passive transfer of IgA into the nursing neonate, and has been implicated in recruitment of these cells to the colon. Such common receptor usage allows for the broad dissemination of IgA plasma cells to a wide range of mucosal tissues. Similar to CCR10 for IgA plasma cells, effector and regulatory T-cell recruitment to the murine colon appears in part to be mediated by their expression of the “orphan” G-protein-coupled receptor GPR15; however, GPR15 has also been implicated in T-cell localization to extraintestinal sites and is, for example, expressed on a wide range of α4β7 integrin + (gut homing) and α4β7 integrin negative (extraintestinal homing) memory T cells in human blood. While the physiologic ligands for GPR15 remain to be characterized, it is of note that GPR15 is not expressed by human colonic FoxP3+ T cells, indicating that inhibition of GPR15 may selectively block inflammatory T-cell influx to the colon in patients with ulcerative colitis. Finally, the chemokine receptor CCR4 has been implicated in effector T-cell localization to both the lung and skin, indicating a potential immunologic common cross talk between these sites. Nevertheless, according to the “multistep adhesion cascade” theory, which proposes that lymphocyte trafficking from the blood into peripheral tissues requires the concerted action of several CAMs, lymphocyte recruitment to distinct mucosal tissues probably involves the use of partly nonoverlapping CAM mechanisms.
Specific induction of the unique GPR15 expression in heterogeneous blood lymphocytes by tobacco smoking
Published in Biomarkers, 2019
Mario Bauer, Jörg Hackermüller, Jana Schor, Stephan Schreiber, Beate Fink, Arkadiusz Pierzchalski, Gunda Herberth
The physiological role of GPR15 remains elusive.Proportion of GPR15-expressing T cells in peripheral blood is an unspecific indicator for pathological processes, such as inflammatory bowel disease, but is a highly specific and sensitive biomarker for chronic tobacco smoking.Smoking behavior should be considered for the suggested therapeutic intervention of the GPR15-GPR15L interaction in autoimmune diseases.