ID: 112: ROLE OF PHOSPHOLIPASE D IN IDIOPATHIC PULMONARY FIBROSIS

Idiopathic pulmonary fibrosis (IPF) is a deadly interstitial disease that leads to scarring and fibrosis of the lung tissue. In pulmonary fibrosis, there is injury and denudation of the alveolar epithelium, which further leads to activation of fibroblasts which differentiate into myofibroblasts. This includes several mechanisms including epithelial to mesenchymal transition (EMT). In this study, we investigated the role of phospholipase D (PLD) in IPF and also its underlying mechanism like EMT and fibroblast proliferation and differentiation. An in vivo murine model of bleomycin-induced pulmonary fibrosis (PF) and in vitro models of murine alveolar type-II epithelial cells (MLE-12) and human lung fibroblasts were used. C57BL/6 and genetically engineered PLD2−/− mice were intratracheally challenged with bleomycin (1.5 U/kg animal) for 14 days and markers of inflammation, EMT and fibrosis were determined. MLE-12 cells were treated with specific PLD1 or PLD2 inhibitors prior to bleomycin (10 mU/ml) challenge, and the role of PLD in EMT and apoptosis of alveolar epithelial cells was studied. Human lung fibroblasts were serum-starved (3h), pretreated with PLD1 or PLD2 inhibitors, and the effect of TGF-β (5 ng/ml) on differentiation of lung fibroblast to myofibroblast was determined. Intra-tracheal instillation of bleomycin in the mice for 14 days leads to the progression of fibrosis in the lung. The lung tissues of the bleomycin treated mice were found to have increased PLD2 protein expression, myofibroblast markers like α-SMA, fibronectin, mesenchymal markers like vimentin, inflammatory cytokines and collagen. Genetic deletion of PLD2 in mice attenuated bleomycin-induced lung inflammation and pulmonary fibrosis. In vitro, MLE-12 cells pretreated with either PLD1 or PLD2 inhibitor did not show a profound reduction either in apoptosis or the expression of transcription factors such as SNAIL, and other markers of EMT. However, MLE-12 cells pretreated with both PLD1 (250 nM) and PLD2 (500 nM) inhibitors were resistant to bleomycin-induced apoptosis, and exhibited reduced expression of SNAIL and mesenchymal markers. On the contrary, human lung fibroblasts pretreated with PLD1 and PLD2 inhibitors showed increased fibroblast to myofibroblast differentiation mediated by TGF-β. The present study suggests a role for PLD2 in bleomycin-induced PF. In vitro, inhibition of both PLD1 and PLD2 was necessary to attenuate bleomycin-induced EMT in epithelial cells and TGF-β mediated differentiation of fibroblasts to myofibroblasts. The in vivo and in vitro results identify the mechanism by which PLD regualtes PF and suggest PLD as a potential therapeutic target in pulmonary fibrosis. This work was supported by National Institutes of Health grant P01 HL98050 to VN.

Prevention and management of internal cerebrospinal fluid shunt infections

Cerebrospinal fluid (CSF) shunt infection is a serious and potentially devastating complication of CSF shunt placement. Younger age, previous CSF shunt infection or revision, and the type of the shunt are important risk factors for shunt infection. More than half of the cases are caused by Staphylococcus aureus and coagulase-negative staphylococci. The biofilm plays a central role in its pathogenesis. CSF cultures remain the gold standard for diagnosis of CSF shunt infection. The most effective way to prevent CSF shunt infection is optimization of sterile protocols and use of proper and timely antibiotic prophylaxis. Management of CSF shunt infection frequently requires removal of all shunt components, placement of a temporary external device, and administration of intravenous antibiotics, followed by reshunting at a later time. This review summarizes and analyses the results of previous reports of CSF shunt infection and assesses the prevention and management of this important entity.

Impact of NK cells on control of HIV infection in humanized BLT mice (P6207)

Evidence suggests natural killer (NK) cells can mediate antiviral activity in HIV-infected humans. Here, we sought to investigate whether the level of NK cell activation in primary HIV infection not only influences the NK cell mediated elimination of HIV infected cells, but also affects the longevity and effectiveness of HIV-specific T cell responses. To address this hypothesis, we monitored HIV viral loads and HIV-specific adaptive immune responses in a humanized BLT mouse model of HIV infection, comparing NK cell-depleted and control mice. Depletion was achieved through the use of an anti-NKp46 antibody prior to HIV infection. Proportions of immune cell subsets and viremia were assessed at baseline and then once a week for at least 5 weeks post-infection using flow cytometry and qRT-PCR. We observed that the impact of NK cells on plasma viral loads varied between batches of mice reconstituted with different tissues. One set of NK cell depleted mice displayed a 4-fold increase in viremia as well as decreased levels of T cell immune activation at 3 weeks post-infection. In a second group of mice reconstituted with independent human tissue, NK cell depletion had no significant effect on viral loads. These results suggest that further investigation is warranted to identify factors accounting for an increased control of HIV replication associated with NK cells in some individuals and not others, such as expression of a protective combination of KIR and HLA alleles.

Modification of immune activation in HIV-1-infected humanized mouse model using TLR7/9 antagonists (113.19)

Background: T cell immune activation is a strong predictor of HIV-1 disease progression, and IFNα production following TLR7 stimulation has been associated with elevated CD8+ T cell activation. We hypothesize that modulation of TLR7 stimulation could be used to manipulate IFNα production and subsequently reduce HIV-1-associated immune activation. Methods: Humanized BLT mice were generated by transplanting irradiated NOD/SCID/IL2Rγc-/- mice with human fetal thymus, liver tissue and human hematopoietic stem cells. After immune reconstitution, human DC, monocyte and T cell populations were detectable in the mice, and in vitro TLR responsiveness of DCs and monocytes reflected those observed in human PBMCs. Humanized mice were infected with HIV-1 and then treated with a TLR7/9 antagonist. The T cell activation markers were examined at each stage by flow cytometry. Results: BLT mice-derived human pDC responses to TLR7 stimulation were significantly blocked by in vitro treatment with the TLR7/9 antagonist (P<0.05). HIV-1 infection of BLT mice led to increased expression of immune activation marker CD38 on human T cells in vivo, and treatment of infected mice with the TLR7/9 antagonist led to a significant reduction in CD38 expression. Conclusion: Treatment of HIV-1-infected humanized BLT mice with TLR7/9 antagonist resulted in significant reduction of HIV-1-associated immune activation, indicating an important role of the TLR7/9 pathway in mediating immune activation in HIV-1.

Neutralizing anti-HIV antibodies develop in a humanized mouse model of HIV-1 infection (105.8)

In BLT (bone marrow-liver-thymus) humanized mice, human thymocytes are educated by autologous human thymic tissue, resulting in functional human T cells. In contrast, limitations to B cell maturation have been noted. But despite this, we show for the first time that HIV infected BLT mice can produce class-switched anti-HIV antibodies with neutralizing activities. Human transitional B cells were present in greater frequencies in BLT mice than adult humans. Most of these cells had a T1 phenotype in the blood and spleen. But despite this B cell maturation defect, class-switched IgG Abs against various HIV proteins were detected by Western Blot in HIV-infected BLT mice. Using ELISA to determine anti-p24 IgG Ab titers, Abs were present as early as 8 weeks post infection (p.i.), with peak Ab titers seen after 15 weeks. One infected mouse demonstrated a peak titer similar to that seen in a chronically infected human. Finally, plasma samples from infected BLT mice after 22 weeks p.i. demonstrated neutralizing activities against the challenge virus. IC50 neutralizing titers in these mice were greater than those from humans infected for up to 5 months, but less than one infected for several years. The ability of humanized BLT mice to generate functional humoral immune responses may be further improved by strategies to improve their B cell maturation, which will further improve the potential of these mice to become a model system to study candidate HIV vaccines and therapies.

Expression of growth factors and oncogenes in normal and tumor-derived human mammary epithelial cells

The expression of genes which may be involved in the regulation of human mammary epithelial cell growth [transforming growth factors alpha and beta] and tumorigenesis [c-myc, erbB2, epidermal growth factor receptor (EGFR), Ha-ras, pS2] has been compared in similarly cultured normal cell strains and tumor cell lines. We have found that the normal breast cells produce high levels of EGFR mRNA, which are translated into nearly 10(5) low affinity epidermal growth factor-binding molecules/cell. In the estrogen receptor-negative lines examined, the EGFR gene was expressed at levels comparable to those in the normal cells. In contrast, EGFR and transforming growth factor alpha mRNAs were reduced in estrogen receptor-positive tumor lines compared to estrogen receptor-negative lines and normal cells. Steady state mRNA levels for transforming growth factor beta, erbB2, c-myc, and Ha-ras in the normal cells were greater than or comparable to those in all of the breast tumor lines. Furthermore, in the absence of gene amplification, only one of the genes examined (i.e., pS2) was overexpressed in a subset of the tumor cells compared to their normal counterparts. Several reports by other investigators have described overexpression of some of these genes in breast biopsies and in tumor lines in studies lacking normal controls. Thus, our results, in which the same genes were not overexpressed compared to normal cells unless amplified, underscore the importance of including appropriate normal controls in studies aimed at defining aberrant patterns of gene expression in tumor cells.

Preliminary report on the treatment of recurrent herpes simplex with poliomyelitis vaccine (Sabin's)

Twenty-three patients with recurrent Herpes simplex have been treated over a period of 4 years (1969–1972) with poliomyelitis vaccine (Sabin’s), given perorally in the dose of 4 drops once a month for 3 months only. In 74% of cases, this treatment resulted in full recovery with no relapse over a follow-up period of 1–4 years. No harmful side-effects whatsoever were noticed in any of the patients. On the basis of these results, it is concluded that the peroral administration of Sabin’s vaccine is a simple, safe and extremely effective method of treating recurrent Herpes simplex infection.

Immunotherapy of superficial dermatomycoses

The long-range efficacy of the standard treatment for superficial dermatomycoses is, in the majority of cases, unsatisfactory, even despite the advent of griseofulvin. The present paper reports an attempt to treat patients suffering from superficial dermatomycoses (Monilia and tinea) by specific immunotherapy. The follow-up period on patients receiving a full course of immunotherapy was 18 months. Of 39 patients receiving immunotherapy with Trichophyton as antigen, 22 were cured completely and an additional 4 showed partial cure (skin lesion healed but nails unaffected). Of 24 patients treated with Monilia antigen, 15 recovered completely. These results, although based on a limited number of cases, are fairly encouraging and point to immunotherapy as an additional method in the treatment of superficial dermatomycoses.

Pustular bacterid

Twelve patients with pustular bacterid were subjected to intradermal bacterial (streptococcal and staphylococcal) test. The test was positive in all patients (and negative in the controls), thus strongly suggesting that pustular bacterid is due to bacterial sensitivity. Attempts to desensitize the 12 patients with injections of bacterial vaccine (containing staphylococci and streptococci) proved very successful: 7 of the patients recovered completely and remaining 5 showed considerable improvement (over a follow-up period of up to 7 years).

Temperatures of Vitrification and Fluidity of Natural Rubber of Different Molecular Weights

The vitrification temperature of natural rubbers does not change with change of molecular weight, whereas the higher the molecular weight of the rubber, the higher is its fluidity temperature.

Heats of Solution and Swelling of Some Synthetic High-Molecular Compounds

1. The heat of solution of a high polymer depends on the nature of the solvent as well as on the nature of the polymer. 2. The value and sign of the heat of solution of a polymer are related to the structure of the polymer and its mechanical behavior. For polymers which have relatively flexible chains, the heats of solution are negative ; for polymers which have relatively rigid chains, the heats of solution are positive. 3. The value and sign of the heat of solution indicate to a certain degree the change of the barrier potential of the polymer chain in any given solvent.