Marina Tuzova

RNAIII-Inhibiting-Peptide-Loaded Polymethylmethacrylate Prevents In Vivo Staphylococcus aureus Biofilm Formation

ABSTRACT Staphylococci, common orthopedic pathogens, form antibiotic-resistant biofilms. Polymethylmethacrylate (PMMA) beads loaded with the quorum-sensing inhibitor RNAIII-inhibiting peptide (RIP) were implanted in rats and shown to prevent methicillin-resistant Staphylococcus aureus infection. RIP release was bimodal, typical of previously-tested antibiotics. These results suggest that RIP-PMMA warrants further evaluation for management of orthopedic infections caused by staphylococci.

Regulation of Cellular Processes by Interleukin-16 in Homeostasis and Cancer

Interleukin‐16 (IL‐16) is generated as a precursor molecule that is cleaved by caspase‐3 to produce a pro‐IL‐16 molecule that functions as a regulator of T cell growth, and a secreted peptide that functions as a CD4 and/or CD9 ligand for induction of cell motility and activation. IL‐16 has been predominantly studied as a contributing factor in the orchestration of an immune response; however, more recently IL‐16 bioactivity has been closely associated with the progression of a number of different cancers. While the association between IL‐16 plasma levels and tumor progression has been reported for many types of cancer, the mechanism for IL‐16 involvement has been partially elucidated for three of the cancer types, cutaneous T cell lymphoma (CTCL), multiple myeloma (MM), and breast cancer. The mechanism for promoting cell growth is different in each of these cancers and involves a sequence mutation in the pro‐molecule facilitating decreased p27KIP1 levels in CTCL; over expression of the secreted IL‐16 molecule to induce proliferation in CTCL T cells, and plasma cells in MM; and increased secreted IL‐16 acting to recruit CD4+ pro‐tumor macrophages in breast cancer. This article will review the cellular process for generating IL‐16, the biological activities for both the pro‐ and secreted forms of the protein, and then the mechanism by which these forms contribute to cancer progression. As a soluble cytokine the ability to reduce or eliminate IL‐16 synthesis through siRNA approaches or bioactivity through the use of neutralizing antibody treatment may represent a novel therapeutic approach. J. Cell. Physiol. 229: 139–147, 2014.

A homologous form of human interleukin 16 is implicated in microglia recruitment following nervous system injury in leech Hirudo medicinalis

In contrast to mammals, the medicinal leech Hirudo medicinalis can completely repair its central nervous system (CNS) after injury. This invertebrate model offers unique opportunities to study the molecular and cellular basis of the CNS repair processes. When the leech CNS is injured, microglial cells migrate and accumulate at the site of lesion, a phenomenon known to be essential for the usual sprouting of injured axons. In the present study, we demonstrate that a new molecule, designated HmIL‐16, having functional homologies with human interleukin‐16 (IL‐16), has chemotactic activity on leech microglial cells as observed using a gradient of human IL‐16. Preincubation of microglial cells either with an anti‐human IL‐16 antibody or with anti‐HmIL‐16 antibody significantly reduced microglia migration induced by leech‐conditioned medium. Functional homology was demonstrated further by the ability of HmIL‐16 to promote human CD4+ T cell migration which was inhibited by antibody against human IL‐16, an IL‐16 antagonist peptide or soluble CD4. Immunohistochemistry of leech CNS indicates that HmIL‐16 protein present in the neurons is rapidly transported and stored along the axonal processes to promote the recruitment of microglial cells to the injured axons. To our knowledge, this is the first identification of a functional interleukin‐16 homologue in invertebrate CNS. The ability of HmIL‐16 to recruit microglial cells to sites of CNS injury suggests a role for HmIL‐16 in the crosstalk between neurons and microglia in the leech CNS repair.

Pro-IL-16 Recruits Histone Deacetylase 3 to the Skp2 Core Promoter through Interaction with Transcription Factor GABP

Pro-IL-16 is a PDZ domain-containing protein expressed in T cells. Our previous work showed that upon activation of normal T cells, pro-IL-16 mRNA and protein are diminished in close correlation to the down-regulation of p27KIP1 protein. In addition, we showed that pro-IL-16 regulates the transcription of Skp2, the mechanism of which, however, remains elusive. In this study, we identified GA binding protein β1 subunit (GABPβ1) and histone deacetylase 3 (HDAC3) as binding partners of pro-IL-16. Interestingly, both GABPβ1 and HDAC3 have canonical PDZ-binding motifs and specifically bind to the first and second PDZ domain of pro-IL-16, respectively. Heat shock cognate protein 70 (HSC70) also copurified with the GST-PDZ1-containing fragment but lacks a C-terminal PDZ binding motif, suggesting that it binds through a different mechanism. We further showed that pro-IL-16 is located in a GABP transcriptional complex bound to the Skp2 promoter. In addition, we demonstrated that HDAC activity is critical for pro-IL-16-induced cell cycle arrest. Taken altogether, these data suggest that pro-IL-16 forms a complex with GABPβ1 and HDAC3 in suppressing the transcription of Skp2. Thus, this study has revealed a novel mechanism with which pro-IL-16 regulates T cell growth through the Skp2-p27KIP1 pathway.

Inhibiting lung lining fluid glutathione metabolism with GGsTop as a novel treatment for asthma.

Asthma is characterized by airway inflammation. Inflammation is associated with oxidant stress. Airway epithelial cells are shielded from this stress by a thin layer of lung lining fluid (LLF) which contains an abundance of the antioxidant glutathione. LLF glutathione metabolism is regulated by γ-glutamyl transferase (GGT). Loss of LLF GGT activity in the mutant GGTenu1 mouse causes an increase in baseline LLF glutathione content which is magnified in an IL-13 model of allergic airway inflammation and protective against asthma. Normal mice are susceptible to asthma in this model but can be protected with acivicin, a GGT inhibitor. GGT is a target to treat asthma but acivicin toxicity limits clinical use. GGsTop is a novel GGT inhibitor. GGsTop inhibits LLF GGT activity only when delivered through the airway. In the IL-13 model, mice treated with IL-13 and GGsTop exhibit a lung inflammatory response similar to that of mice treated with IL-13 alone. But mice treated with IL-13 and GGsTop show attenuation of methacholine-stimulated airway hyper-reactivity, inhibition of Muc5ac and Muc5b gene induction, decreased airway epithelial cell mucous accumulation and a fourfold increase in LLF glutathione content compared to mice treated with IL-13 alone. Mice treated with GGsTop alone are no different from that of mice treated with saline alone, and show no signs of toxicity. GGsTop could represent a valuable pharmacological tool to inhibit LLF GGT activity in pulmonary disease models. The associated increase in LLF glutathione can protect lung airway epithelial cells against oxidant injury associated with inflammation in asthma.

Interleukin-16 as a Marker of Sézary Syndrome Onset and Stage

IntroductionSézary syndrome is one of the most common forms of cutaneous T cell lymphoma (CTCL). It is characterized by skin infiltration of malignant T cells. We examined interleukin-16, a potent T cell chemoattractant and cell-cycle regulator, as a prospective marker of disease onset and stage.MethodsThe correlation of total intracellular interleukin-16 and surface CD26 was studied by flow cytometry. Confocal microscopy was performed to determine localization of interleukin-16 at different stages of the disease. The levels of interleukin-16 in plasma and culture supernatants were examined by enzyme-linked immunoassay. Additionally, lymphocytes from stage IB patients were cultured in the presence of interleukin-16 alone and in combination with interleukin-15, and their ability to survive and proliferate was determined by cell counts and [3H]TdR incorporation.ResultsThe data indicate that loss of both nuclear and intracellular pro-interleukin-16 highly correspond to disease stage, with a concomitant increase in secreted mature interleukin-16 in both culture supernatants and patients’ plasma that peaks at stage IB. Loss of intracellular interleukin-16 strongly corresponded to loss of surface CD26, which has been shown to occur with more advanced stage of CTCL. Nuclear translocation of pro-interleukin-16 was not observed in late stages of Sézary syndrome, indicating this loss is not reversible.ConclusionsWe propose that it is feasible to use plasma levels of IL-16 as a potential diagnostic marker of Sézary syndrome and to use loss of intracellular IL-16 as a prognostic indicator of disease severity and stage.

Vitamin D supplementation during pregnancy: Effect on the neonatal immune system in a randomized controlled trial

&NA; Figure. No caption available. Background: Programming of the immune system during fetal development can influence asthma‐related risk factors and outcomes in later life. Vitamin D is a well‐recognized immune modulator, and deficiency of this nutrient during pregnancy is hypothesized to influence disease development in offspring. Objective: We sought to investigate the effect on neonatal immunity of maternal supplementation with 4400 IU/d vitamin D3 during the second and third trimesters of pregnancy by using a subset of cord blood samples from a randomized, double‐blind, placebo‐controlled clinical trial (the Vitamin D Antenatal Asthma Reduction Trial). Methods: Cord blood samples from neonates born to mothers supplemented with 4400 IU/d (n = 26) or 400 IU/d (n = 25) of vitamin D3 were analyzed for immune cell composition by flow cytometry, Toll‐like receptor (TLR) expression by quantitative PCR, and cytokine secretion after stimulation with mitogenic, TLR, and T‐cell stimuli by cytometric bead array. Responsiveness to the glucocorticoid dexamethasone was determined. Results: Supplementation of mothers with 4400 IU of vitamin D3 resulted in an enhanced broad‐spectrum proinflammatory cytokine response of cord blood mononuclear cells to innate and mitogenic stimuli (P = .0009), with an average 1.7‐ to 2.1‐fold increase in levels of several proinflammatory cytokines (GM‐CSF, IFN‐&ggr;, IL‐1&bgr;, IL‐6, and IL‐8) across stimuli, a higher gene expression level of TLR2 (P = .02) and TLR9 (P = .02), a greater than 4‐fold increase in IL‐17A (P = .03) production after polyclonal T‐cell stimulation, and an enhanced IL‐10 response of cord blood mononuclear cells to dexamethasone treatment in culture (P = .018). Conclusion: Vitamin D exposure during fetal development influences the immune system of the neonate, which can contribute to protection from asthma‐related, including infectious, outcomes in early life.

CCR4 T cell recruitment to the skin in mycosis fungoides: potential contributions by thymic stromal lymphopoietin and interleukin-16

Abstract Mycosis fungoides (MF) is characterized by skin accumulation of CCR4+CCR7- effector memory T cells; however the mechanism for their recruitment is not clearly identified. Thymic Stromal Lymphopoietin (TSLP) is a keratinocyte-derived cytokine that triggers Th2 immunity and is associated with T cell recruitment to the skin in atopic dermatitis. Interleukin-16 (IL-16) is a chemoattractant and growth factor for CD4+ T cells. We hypothesized that TSLP and IL-16 could contribute to recruitment of malignant T cells in MF. We found elevated TSLP and IL-16 in very early stage patients’ plasma and skin biopsies, prior to elevation in CCL22. Both TSLP and IL-16 induced migratory responses of CCR4+TSLPR+CD4+CCR7−CD31+ cells, characteristic of malignant T cells in the skin. Co-stimulation also resulted in significant proliferative responses. We conclude that TSLP and IL-16, expressed at early stages of disease, function to recruit malignant T cells to the skin and contribute to their enhanced proliferation.