Lck signaling inhibition causes improvement in clinical features of psoriatic inflammation through reduction in inflammatory cytokines in CD4+ T cells in imiquimod mouse model.

Psoriasis is a chronic dermal inflammatory disease with a world-wide prevalence in which different immune/non-immune cells, e.g. T cells, macrophages, neutrophils, and keratinocytes play a decisive role. These immune cells interact among themselves by releasing multiple mediators which eventually cause characteristic psoriatic plaques in the skin. T cells are reported to be significant contributors to psoriatic inflammation through release of multiple cytokines which are controlled by several kinases, one of them being Lymphocyte-specific protein tyrosine kinase (Lck). Lck has been reported to be crucial for expression/production of several key inflammatory cytokines though modulation of several other kinases/transcription factors in T cells. Therefore, in this investigation, effect of Lck inhibitor, A-770041 was examined on PLCγ, p38MAPK, NFATc1, NFkB and STAT3, TNF-α, IFN-γ, Foxp3, IL-17A, in CD4+ T cells in imiquimod (IMQ)-induced psoriatic inflammation in mice. Results from the present study exhibit that p-Lck expression is enhanced in CD4+ T cells of IMQ-treated mice which is concomitant with enhanced clinical features of psoriatic inflammation (ear/back skin thickness, MPO activity, acanthosis/leukocytic infiltration) and molecular parameters (enhanced expression of p-Lck, p-PLCγ, p-p38-MAPK, NFATc1, p-NFkB, TNF-α, IFN-γ, p-STAT3, and IL-17A in CD4+ T cells). Inhibition of Lck signaling led to amelioration of clinical features of psoriasis through attenuation of Th1/Th17 immune responses and upregulation of Treg cells in IMQ-treated mice. In summary, current investigations reveal that Lck signaling is a crucial executor of inflammatory signaling in CD4+ T cells in the context of psoriatic inflammation. Therefore, Lck inhibition may be pursued as an effective strategy to counteract psoriatic inflammation.

An Unbiased Immunoaffinity-Based Strategy for Profiling Covalent Drug Targets In Vivo.

Activity-based chemical proteomics approaches used for identifying cellular targets of drugs are mainly dependent on the availability of probes derived from drugs. However, all chemical probes are structurally different from the drugs themselves and cannot fully mimic the real actions of drugs in cells. Here we present a concise and unbiased immunoaffinity-based strategy for identifying covalent drug targets in vivo. By using the specific antibody, we not only confirm the well-known ibrutinib-binding target BTK, but also identify some previously undescribed strongly binding proteins, such as CKAP4 in human cell lines and TAP1 in mouse organs. The observed target profiles between species may partially explain why certain drug candidates are very effective in mice but not in humans. This approach avoids the chemical modification of drugs, eliminates the nonspecific bindings of chemical probes, and allows to unbiasedly decode the underlying mechanisms of action of covalent drugs.

Imaging the neuroimmune response to alcohol exposure in adolescent baboons: a TSPO PET study using 18 F-DPA-714.

The effects of acute alcohol exposure to the central nervous system are hypothesized to involve the innate immune system. The neuroimmune response to an initial and acute alcohol exposure was investigated using translocator protein 18 kDa (TSPO) PET imaging, a non-invasive marker of glial activation, in adolescent baboons. Three different alcohol-naive adolescent baboons (3-4 years old, 9 to 14 kg) underwent 18 F-DPA-714 PET experiments before, during and 7-12 months after this initial alcohol exposure (0.7-1.0 g/l). The brain distribution of 18 F-DPA-714 (VT ; in ml/cm3 ) was estimated in several brain regions using the Logan plot analysis and the metabolite-corrected arterial input function. Compared with alcohol-naive animals (VTbrain  = 3.7 ± 0.7 ml/cm3 ), the regional VT s of 18 F-DPA-714 were significantly increased during alcohol exposure (VTbrain  = 7.2 ± 0.4 ml/cm3 ; p < 0.001). Regional VT s estimated several months after alcohol exposure (VTbrain  = 5.7 ± 1.4 ml/cm3 ) were lower (p < 0.001) than those measured during alcohol exposure, but remained significantly higher (p < 0.001) than in alcohol-naive animals. The acute and long-term effects of ethanol exposure were observed globally across all brain regions. Acute alcohol exposure increased the binding of 18 F-DPA-714 to the brain in a non-human primate model of alcohol exposure that reflects the 'binge drinking' situation in adolescent individuals. The effect persisted for several months, suggesting a 'priming' of glial cell function after initial alcohol exposure.

Ibrutinib Therapy Increases T Cell Repertoire Diversity in Patients with Chronic Lymphocytic Leukemia.

The Bruton's tyrosine kinase inhibitor ibrutinib is a highly effective, new targeted therapy for chronic lymphocytic leukemia (CLL) that thwarts leukemia cell survival, growth, and tissue homing. The effects of ibrutinib treatment on the T cell compartment, which is clonally expanded and thought to support the growth of malignant B cells in CLL, are not fully characterized. Using next-generation sequencing technology, we characterized the diversity of TCRß-chains in peripheral blood T cells from 15 CLL patients before and after 1 y of ibrutinib therapy. We noted elevated CD4+ and CD8+ T cell numbers and a restricted TCRß repertoire in all pretreatment samples. After 1 y of ibrutinib therapy, elevated peripheral blood T cell numbers and T cell-related cytokine levels had normalized, and T cell repertoire diversity increased significantly. Dominant TCRß clones in pretreatment samples declined or became undetectable, and the number of productive unique clones increased significantly during ibrutinib therapy, with the emergence of large numbers of low-frequency TCRß clones. Importantly, broader TCR repertoire diversity was associated with clinical efficacy and lower rates of infections during ibrutinib therapy. These data demonstrate that ibrutinib therapy increases diversification of the T cell compartment in CLL patients, which contributes to cellular immune reconstitution.

Efficacy of a Cancer Vaccine against ALK-Rearranged Lung Tumors.

Non-small cell lung cancer (NSCLC) harboring chromosomal rearrangements of the anaplastic lymphoma kinase (ALK) gene is treated with ALK tyrosine kinase inhibitors (TKI), but the treatment is successful for only a limited amount of time; most patients experience a relapse due to the development of drug resistance. Here, we show that a vaccine against ALK induced a strong and specific immune response that both prophylactically and therapeutically impaired the growth of ALK-positive lung tumors in mouse models. The ALK vaccine was efficacious also in combination with ALK TKI treatment and significantly delayed tumor relapses after TKI suspension. We found that lung tumors containing ALK rearrangements induced an immunosuppressive microenvironment, regulating the expression of PD-L1 on the surface of lung tumor cells. High PD-L1 expression reduced ALK vaccine efficacy, which could be restored by administration of anti-PD-1 immunotherapy. Thus, combinations of ALK vaccine with TKIs and immune checkpoint blockade therapies might represent a powerful strategy for the treatment of ALK-driven NSCLC.

Corticosteroid effects on COPD alveolar macrophages: dependency on cell culture methodology.

It is unclear whether cell culture methodology affects the corticosteroid sensitivity of chronic obstructive pulmonary disease (COPD) alveolar macrophages. We compared the effect of a short and a long isolation procedure on corticosteroid inhibition of lipopolysaccharide (LPS) stimulated cytokine release from COPD alveolar macrophages. We also investigated signalling pathways associated with macrophage activation during cell isolation. Macrophages cultured using a short isolation protocol released higher unstimulated levels of tumour necrosis factor (TNF)-α and chemokine C-X-C motif ligand (CXCL) 8; these macrophages were less sensitive to corticosteroid inhibition of LPS stimulated TNF-α and CXCL8 release when compared to a long isolation procedure. This was associated with increased p38 mitogen activated kinase (MAPK) activation. The p38 MAPK inhibitor, BIRB-796, significantly reduced unstimulated cytokine release. A key finding of this study was that both cell culture methods showed no difference in the corticosteroid sensitivity between COPD and control macrophages. We conclude that the culture of alveolar macrophages using a short isolation procedure alters cytokine production through p38 MAPK activation; this is associated with a change in corticosteroid sensitivity.

Celecoxib desensitization: continued temozolomide/celecoxib chemotherapy after a celecoxib-induced hypersensitivity reaction.

Cox-2 inhibitors have been identified as promising candidates for cancer therapy. Several studies have recently proposed the use of celecoxib in long-term low-intensity chemotherapy protocols for recurrent tumors. However, drug-induced hypersensitivity reactions may force discontinuation of the medication and, thus, significantly complicate successful care. Here, we report on celecoxib desensitization after a celecoxib-induced skin reaction, thereby allowing the continuation of temozolomide/celecoxib chemotherapy in a young patient with recurrent astrocytoma.

Perinatal exposure to Δ9-tetrahydrocannabinol triggers profound defects in T cell differentiation and function in fetal and postnatal stages of life, including decreased responsiveness to HIV antigens.

Marijuana abuse is very prominent among pregnant women. Although marijuana cannabinoids have been shown to exert immunosuppression in adults, virtually nothing is known about the effects of marijuana use during pregnancy on the developing immune system of the fetus and during postnatal life. We noted that murine fetal thymus expressed high levels of the cannabinoid receptors CB1 and CB2. Moreover, perinatal exposure to Δ(9)-tetrahydrocannabinol (THC) had a profound effect on the fetus as evidenced by a decrease in thymic cellularity on gestational days 16, 17, and 18 and postgestational day 1 and marked alterations in T cell subpopulations. These outcomes were reversed by CB1/CB2 antagonists, suggesting that THC-mediated these effects through cannabinoid receptors. Thymic atrophy induced in the fetus correlated with caspase-dependent apoptosis in thymocytes. Thymic atrophy was the result of direct action of THC and not based on maternal factors inasmuch as THC was able to induce T cell apoptosis in vitro in fetal thymic organ cultures. It is noteworthy that perinatal exposure to THC also had a profound effect on the immune response during postnatal life. Peripheral T cells from such mice showed decreased proliferative response to T cell mitogen as well as both T cell and antibody response to HIV-1 p17/p24/gp120 antigens. Together, our data demonstrate for the first time that perinatal exposure to THC triggers profound T cell dysfunction, thereby suggesting that the offspring of marijuana abusers who have been exposed to THC in utero may be at a higher risk of exhibiting immune dysfunction and contracting infectious diseases including HIV.

Emerging strategies to treat chronic immune thrombocytopenic purpura.

Immune thrombocytopenic purpura (ITP) is a fairly common hematological disorder and is a minor disease for many affected patients; most are in good health, and many can tolerate low platelet counts without the need for treatment. For the majority of patients who do undergo treatment, first-line therapies, including corticosteroids, are effective in increasing platelet counts, although long-term use can be associated with adverse effects. Second-line therapies, such as immunosuppressants, have been largely untested in controlled studies of ITP patients. Like first-line therapies, splenectomy is effective for many patients; however, it is frequently avoided by physicians who prefer the use of alternative drug therapies due to concerns about safety risks and is often declined by patients reluctant to undergo surgery. Thus, approaches to avoid or defer the use of splenectomy have been actively pursued. An anti-CD20 antibody, rituximab, can limit the production of autoantibodies, but reactivated viral infections have been reported with its use. Agents that directly stimulate platelet production, such as thrombopoietin (TPO) receptor-binding agents, have shown promise in clinical trials of ITP patients as well as in hepatitis C virus-infected individuals with thrombocytopenia. Two TPO receptor agonists in advanced clinical development--eltrombopag and AMG 531--are discussed here. Both eltrombopag and AMG 531 appear to be effective in raising platelet counts and both have been well tolerated in clinical trials to date. However, potential safety issues with thrombopoietic growth factors include thrombocytosis, rebound thrombocytopenia, and increased bone marrow fibrosis. Further testing will determine which safety issues--if any--are of clinical concern.

Effects of a dual inhibitor of tumor necrosis factor-alpha and interleukin-1 on lipopolysaccharide-induced lung injury in rats: involvement of the p38 mitogen-activated protein kinase pathway.

OBJECTIVE: Sepsis is a major cause of adult respiratory distress syndrome. In this study, we evaluated the effect of FR167653, which is a potent suppressant of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 production, on lipopolysaccharide (LPS)-induced lung injury and lethality in rats, and we examined the involvement of p38 mitogen-activated protein (MAP) kinase in the action of FR167653. DESIGN: Prospective, randomized study. SETTING: Animal research facility in a university. SUBJECTS: Male Sprague-Dawley rats weighing 200-270 g. INTERVENTIONS: All the animals were assigned to one of the following four groups: control group, FR-only group, LPS-only group, and LPS/FR group. Animals in the LPS-only and LPS/FR groups received 6 mg/kg of LPS intravenously. The animals in the FR-only and LPS/FR groups also received an infusion of FR167653 at 0.2 mg x kg(-1) x hr(-1), commencing 30 mins before the LPS (or vehicle) injection and continuing for 5.5 hrs. MEASUREMENTS AND MAIN RESULTS: LPS significantly induced the accumulation of pulmonary neutrophils and lung edema, both of which were significantly attenuated by treatment with FR167653. FR167653 also significantly decreased the LPS-induced lethality. Histologically, tissue damage was milder in the LPS/FR group than in the LPS-only group. Serum concentrations of TNF-alpha and IL-1beta and plasma concentrations of thromboxane B2 were all suppressed in the LPS/FR group compared with the LPS-only group. Western blot analysis revealed that FR167653 inhibited the phosphorylation of p38 MAP kinase in lung tissues. CONCLUSIONS: FR167653 administration decreased serum TNF-alpha and IL-1beta concentrations, which was associated with decreased lung injury and lethality. The mechanism responsible for the decreased TNF-alpha and IL-1 may be related to the inhibitory effect of FR167653 on p38 MAP kinase activation.