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These experiments aimed to understand the relationship between interleukin 10 (IL10), the IL10 receptor subunits, and progesterone (P4) at the time of parturition. We hypothesized that there is a biologic connection between IL10 and P4, supporting an immunomodulatory mechanism for the onset of labor. Using samples from control and P4-treated pregnant mice, we assessed the production of IL10 and its receptor subunits (IL10Rα and IL10Rβ) in gestational tissues. After preliminary studies, P4-treated pregnant mice were compared with controls to assess for differences in IL10 and IL10 receptor subunit expression throughout gestation. To investigate the contribution of the P4 receptor at the onset of labor, we performed timed studies on pregnant mice after treatment with RU486. Samples collected included placentas, placentation sites, and maternal livers. IL10, IL10Rα, and IL10Rβ levels were measured in homogenized tissue using ELISA assays; the cytokine results were normalized for homogenate protein concentration. Control mice delivered on gd 18-19, and P4 treatment prevented parturition to beyond gd 20, as expected. In treated mice, P4 not only prevented the anticipated nadir of IL10 at term, but maintained elevated levels of IL10 through gd 20 (p < 0.05). P4 also reversed the anticipated decrease of the IL10Rα, which was increased in P4-treated mice (p < 0.05). Treatment with RU486 did not modulate the expression of IL10 or IL10Rα, but showed a significant decrease in the level of IL10Rβ (p < 0.05). Progesterone functions at least in part through the IL10 signaling pathway to prolong gestation.

Glutamatergic AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) and NMDA (N-methyl-D-aspartate) receptors are implicated in diverse functions ranging from synaptic plasticity to cell death. They are heterotetrameric proteins whose subunits are derived from multiple distinct gene families. The subunit composition of these receptors determines their permeability to monovalent and/or divalent cations, but it is not entirely clear how this selectivity arises in native and recombinantly-expressed receptor populations. By analyzing the sequence of amino acids lining the selectivity filters within the pore forming membrane helices (M2) of these subunits and by correlating subunit stoichiometry of these receptors with their ability to permeate Na+ and/or Ca2+, we propose here a mathematical model for predicting cation selectivity and permeability in these receptors. The model proposed is based on principles of charge attractivity and charge neutralization within the pore forming region of these receptors; it accurately predicts and reconciles experimental data across various platforms including Ca2+ permeability of GluA2-lacking AMPARs and ion selectivity within GluN3-containing di- and tri-heteromeric NMDARs. Additionally, the model provides insights into biophysical mechanisms regulating cation selectivity and permeability of these receptors and the role of various subunits in these processes.

Background: Gamma-aminobutyric acid type A (GABAA) receptors are thought to play a role in the functioning of the immune system. GABAA receptors have 19 types of subunits, the components of which determine their physiological functions. However, the subunits that are expressed in immune cells during inflammation have not been fully investigated. Recent reports have shown that anesthetic agents may affect the gene expression of GABAA receptors subunits in immune cells. Therefore, we aimed to investigate the changes in GABAA receptor subunit gene expression during macrophage differentiation and propofol administration in order to clarify the relationship between the expression of GABAA receptors and the immunomodulatory effect of propofol.Methods: Human acute monocytic leukemia (THP-1) cells were differentiated into macrophage-like cells (M0 THP-1); subsequently, M0 THP-1 cells were differentiated into inflammatory M1 macrophage-like cells (M1 THP-1). Propofol was administered during the differentiation into M1 THP-1 cells. Using reverse transcriptase polymerase chain reaction, we examined which GABAA receptor subunit genes were expressed and whether there were changes in the gene expression during macrophage differentiation and propofol administration in THP-1 cells.Results: The expression of the α1, α4, β1, β2, γ1, and γ2 subunits increased during differentiation into M0 THP-1 cells. The expression of the α1, α4, β1, β2, γ2, and δ subunits decreased and that of the γ1 subunit increased during differentiation into M1 THP-1 cells. The gene expression of the α1, α4, and β2 subunits increased upon administering propofol during differentiation into M1 THP-1 cells.Conclusions: The gene expression of GABAA receptor subunits changed during macrophage differentiation in THP-1 cells. The expressions of α1 and α4 increased following propofol administration during the differentiation into M1 THP-1 cells, which may indicate that the GABAA receptor is involved in the immunosuppressive effects of propofol. This study can help in the choice of anesthetic agents for proinflammatory conditions such as highly-invasive surgery.

The cytokines interleukin-4 (IL-4) and IL-13 bind to their shared receptor subunit IL-4Rα to direct the alternative activation of macrophages to promote immunosuppression and wound healing. Activated IL-4 and IL-13 receptors recruit the tyrosine phosphatases SHP-1 and SHP-2, which dephosphorylate and inhibit the IL-4Rα subunit. Here, we report that the immunoreceptor SIRPα spatially restricted SHP-2 to promote IL-4 and IL-13 signaling and the alternative activation of macrophages. This effect required the cytoplasmic ITIMs or ITSMs of SIRPα, which underwent tyrosine phosphorylation by Bruton’s tyrosine kinase (Btk) that was activated in response to IL-4 and IL-13. This phosphorylation event resulted in the recruitment of SHP-2 to SIRPα and prevented it from binding to and inhibiting IL-4R and IL-13R. Binding of the ligand CD47 to the SIRPα extracellular domain promoted the Btk-mediated phosphorylation of the SIRPα cytoplasmic domain and hence SHP-2 sequestration. Conversely, loss of SIRPα enabled SHP-2 to bind to the γC and IL-13Rα1 subunits of IL-4R and IL-13R, respectively, and dephosphorylate IL-4Rα, dampening its signaling. Impaired wound healing in Sirpα

The outer membrane translocase (TOM) is the import channel for nuclear-encoded mitochondrial proteins. The general import pore contains Tom40, Tom22, Tom5, Tom6, and Tom7. Precursor proteins are bound by the (peripheral) receptor proteins Tom20, Tom22, and Tom70 before being imported by the TOM complex. Here we investigated the association of the receptor Tom20 with the TOM complex. Tom20 was found in the TOM complex, but not in a smaller subcomplex. In addition, a subcomplex was found without Tom40 and Tom7 but with Tom20. Using single particle tracking of labeled Tom20 in overexpressing human cells, we show that Tom20 has, on average, higher lateral mobility in the membrane than Tom7/TOM. After ligation of Tom20 with the TOM complex by post-tranlational protein trans-splicing using the traceless, ultrafast cleaved Gp41-1 integrin system, a significant decrease in the mean diffusion coefficient of Tom20 was observed in the resulting Tom20–Tom7 fusion protein. Exposure of Tom20 to high substrate loading also resulted in reduced mobility. Taken together, our data show that the receptor subunit Tom20 interacts dynamically with the TOM core complex. We suggest that the TOM complex containing Tom20 is the active import pore and that Tom20 is associated when substrate is available.

Chronic rhinosinusitis with nasal polyps is a type 2-mediated inflammatory disease associated with significant burden due to symptoms and high recurrence rate after surgery. Dupilumab, a monoclonal antibody against the interleukin-4 receptor subunit α, has demonstrated good clinical efficacy and acceptable safety in phase II and phase III trials.

Dupilumab is a treatment option newly licensed for adolescents with moderate to severe atopic dermatitis (AD). It reduces type 2 inflammation by blocking the shared receptor subunit for IL-4/-13. Dupilumab affects three disease mechanisms in atopic dermatitis: the skin barrier, the Th2-cell differentiation and the class switch to IgE. This report is based on a systematic literature search of the PubMed Database.Dupilumab showed promising results in improving AD signs, symptoms and quality of life in adolescents with moderate to severe AD. The safety profile of dupilumab in adolescents with moderate to severe AD closely resembled the known safety profile of dupilumab in adults with moderate to severe AD. Injection-site reactions and conjunctivitis were the relevant side-effects. Skin infections were less frequently observed compared to placebo.Dupilumab was approved by the Food and Drug Administration in March 2019 and by the European Medicines Agency in August 2019 for the treatment of adolescents with moderate to severe atopic dermatitis whose disease is not adequately controlled with topical therapies or when those therapies are not advisable. Since it is the first licensed drug it will likely become the reference drug for adolescents with moderate to severe AD.

Lymphopenia-induced homeostatic proliferation (LIP) is a critical mechanism for restoring T cell immunity upon lymphodepleting insults or infections. LIP is primarily driven by homeostatic cytokines, such as IL-7 and IL-15, but not all T cells respond with the same efficiency to homeostatic proliferative cues. Although CD8 T cells vigorously proliferate under lymphopenic conditions, naive CD4 T cells are substantially impaired in their response to homeostatic cytokines, and they fail to fully expand. In this study, we show that the availability of IL-2Rβ (CD122), which is a receptor subunit shared by IL-2 and IL-15, affects both the cytokine responsiveness and the LIP of naive CD4 T cells in the mouse. The enumeration of surface IL-2Rβ molecules on murine naive CD4 and naive CD8 T cells revealed a 5-fold difference in IL-2Rβ abundance. Notably, it was the limited availability of IL-2Rβ that impaired CD4 T cell responsiveness to IL-15 and suppressed their LIP. As such, forced IL-2Rβ expression on CD4 T cells by transgenesis bestowed IL-15 responsiveness onto naive CD4 T cells, which thus acquired the ability to undergo robust LIP. Collectively, these results identify IL-2Rβ availability as a new regulatory mechanism to control cytokine responsiveness and the homeostatic proliferation of murine CD4 T cells.

Introduction Atopic dermatitis (AD, eczema) is familial chronic inflammatory skin disease of complex etiology and increasing prevalence. Dupilumab is an IL-4 receptor subunit alpha (IL-4Rα) antagonist that is the first Food and Drug Administration-approved biological therapy for moderate-to-severe adult AD inadequately controlled with topical therapies. Adverse effects reported in the literature include injection site reactions, conjunctivitis, headache, and nasopharyngitis. Objective We report the first cases of hyperhidrosis and bromhidrosis as side effects from dupilumab (Dupixent®) for the treatment of AD. Case Reports Case 1 is a 20-year-old woman with controlled allergic rhinitis and severe AD reported axillary hyperhidrosis with bromhidrosis, comparable to sweat from high-intensity exercise, with no relief from several different over-the-counter antiperspirants. Case 2 is a 61-year-old woman with history of chronic asthma, allergic contact dermatitis, allergic rhinitis, and AD noticed markedly increased sweating with bromhidrosis that was reminiscent of her menopausal symptomology, about 3 months after initiating dupilimab. Discussion Traditional immunosuppressive agents and corticosteroids have limited efficacy, numerous side effects, and increased risk of infection. The safety profile and efficacy of the newly approved IL-4Rα antagonist dupilumab may be favorable to oral immunosuppressants, but its use remains limited to severe recalcitrant cases, due to financial implications and lack of long-term safety data and comparative head-to-head trials. Conclusion We report improved outcomes with dupilumab, in addition to unpublished cases of bromhidrosis and hyperhidrosis in 2 patients with AD. This report of additional complications may inspire further clinical research and assist clinicians in considering the option of dupilumab for uncontrolled AD, despite aggressive traditional treatment.

Cytokine signaling is challenging to study and therapeutically exploit as the effects of these protein are often pleiotropic. A subset of cytokines can, however, exert signal specificity via association with latency-inducing proteins which cage the cytokine until disrupted by discreet biological stimuli. Inspired by this precision, here we describe a strategy for synthetic induction of cytokine latency via modification with photo-labile polymers that mimic latency while attached, then restore protein activity in response to light, thus controlling the magnitude, duration, and location of cytokine signals. We characterize the high dynamic range of latent cytokine activity modulation and find that polymer-induced latency, alone, can prolong in vivo circulation and bias receptor subunit binding. We further show that protein de-repression can be achieved with near single-cell resolution and demonstrate the feasibility of transcutaneous photoactivation. Future extensions of this approach could enable multicolor, optical reprogramming of cytokine signaling networks and more precise immunotherapies.

AMPA Receptor GluA2 Subunit Defects Are a Cause of Neurodevelopmental Disorders Salpietro V, Dixon CL, Guo H, et al. Nat Commun. 2019;10:3094. doi:10.1038/s41467-019-10910-w4-amino-3-hydroxy-5-methyl-4isoxazolepropionic acid (AMPA) receptors (AMPARs) are tetrameric ligand–gated channels made up of combinations of GluA1-4 subunits encoded by GRIA1-4 genes. GluA2 has an especially important role because, following posttranscriptional editing at the Q607 site, it renders heteromultimeric AMPARs Ca2+-impermeable, with a linear relationship between current and transmembrane voltage. Here, we report heterozygous de novo GRIA2 mutations in 28 unrelated patients with intellectual disability (ID) and neurodevelopmental abnormalities, including autism spectrum disorder (ASD), Rett syndrome-like features, and seizures or developmental epileptic encephalopathy (DEE). In functional expression studies, mutations lead to a decrease in agonist-evoked current mediated by mutant subunits compared to wild-type channels. When GluA2 subunits are coexpressed with GluA1, most GRIA2 mutations cause a decreased current amplitude, and some also affect voltage rectification. Our results show that de novo variants in GRIA2 can cause neurodevelopmental disorders, complementing evidence that other genetic causes of ID, ASD, and DEE also disrupt glutamatergic synaptic transmission.

Background: The smoking behavior of American Indians (AI) differs from that of non-Hispanic whites (NHW). Typically light smokers, cessation interventions in AIs are generally less effective. To develop more effective cessation programs for AIs, clinicians, researchers, and public health workers need a better understanding of the genetic factors involved in their smoking behavior. Our aim was to assess whether SNPs associated with smoking behavior in NHWs are also associated with smoking in AIs. Methods: We collected questionnaire data on smoking behaviors and analyzed blood and saliva samples from two Tribal populations with dramatically different cultures and smoking prevalence, one in the Northern Plains (n = 323) and the other in the Southwest (n = 176). A total of 384 SNPs were genotyped using an Illumina custom GoldenGate platform. Samples were also assessed for cotinine and 3-hydroxycotinine as markers of nicotine intake and nicotine metabolite ratio. Results: Among 499 participants, we identified, in the Northern Plains sample only, a variant of the gamma-aminobutyric acid receptor subunit alpha-2 (GABRA2) (rs2119767) on chromosome 4p that was associated with many of the intake biomarkers of smoking we examined, suggesting a role for this gene in modifying smoking behavior in this population. We also identified three SNPs, in the Southwest sample only, as significant correlates of only cigarettes per day: rs4274224, rs4245147 (both dopamine receptor D2 gene), and rs1386493 (tryptophan hydroxylase 2 gene). Conclusions: The contribution of many genes known to underlie smoking behaviors in NHWs may differ in AIs. Impact: Once validated, these variants could be useful in developing more effective cessation strategies.