Sussan K. Ardestani

Immunological and cytotoxicological characterization of tuberculin purified protein derivative (PPD) conjugated to single-walled carbon nanotubes.

Tuberculosis (TB) represents one of the leading killers among all infectious disease. Protection against TB depends on the activation of T-helper type I (Th1) immune response. Carbon nanotubes (CNTs) have attracted considerable attention because of their potential applications as new nanovehicle. In the current study, tuberculin purified protein derivative (PPD) was conjugated to carboxylated single-walled carbon nanotubes (SWCNTs). Cytotoxicity of the carboxylated SWCNT and SWCNT-PPD conjugate was analyzed with MTT assay and by reactive oxygen species (ROS) and nitric oxide (NO) generation. Male BALB/c mice were immunized with BCG, PPD, SWCNT-PPD conjugate and PPD in complete Freunds adjuvant (CFA). Induction of cellular immune response was analyzed by measuring the levels of Th1 cytokines (IFN-gamma and IL-12) and Th2 cytokines (IL-10 and IL-5). Immunization with non-conjugated PPD or PPD in Freunds adjuvant induced a Th2 cytokine response while immunization with BCG resulted to a mixed Th1/Th2 cytokine response. In contrast, PPD in conjugation with SWCNT generated preferentially a Th1-type cytokine response in the absence of potential cytotoxic effects.

Serum levels of IL-8 and IL-6 in the long term pulmonary complications induced by sulfur mustard: Sardasht-Iran Cohort Study.

Sulfur mustard (SM) is a blistering chemical agent which has short and long term toxicity against many organs. The respiratory tract is one of the main targets, and is the most disabling long term complication of SM. Inflammatory mediators especially IL-8 and IL-6 play the primary role in the various chronic pulmonary diseases. Sardasht-Iran Cohort Study (SICS) was designed to evaluate immunological and molecular parameters in SM exposed people 20 years after exposure. In the present study, the association of the serum levels of IL-8, IL-6, C reactive protein (CRP) and rheumatoid factor (RF) with long term pulmonary involvement was evaluated. There were 348 exposed and 120 control participants. The clinical evaluations were done for all subjects and Spirometry was performed according to American Thoracic Society Criteria. Severity of pulmonary involvement was assessed by Global Initiative for chronic Obstructive Lung Disease (GOLD) classification. The serum levels of IL-8, IL-6 and RF were assessed by ELISA assay. CRP was assessed by photometric method. The serum levels of IL-8 and IL-6 significantly decreased in the SM exposed participants compared to the control group. There were no significant associations between the serum levels of IL-8 and pulmonary symptoms (chronic cough, sputum, hemoptysis, and dyspnea), pulmonary findings (crackles, rales, and wheezing) as well as spirometry parameters. IL-6 was associated with wheezing and CRP was associated with wheezing and rales in SM exposed group. We concluded the serum levels of these inflammatory mediators probably do not have any major role in pathogenesis and persistence of pulmonary complications and do not reflect the degree of severity of pulmonary involvement following SM exposure.

Naphthalene metabolism in Nocardia otitidiscaviarum strain TSH1, a moderately thermophilic microorganism.

The thermophilic bacterium Nocardia otitidiscaviarum strain TSH1, originally isolated in our laboratory from a petroindustrial wastewater contaminated soil in Iran, grows at 50 degrees C on a broad range of hydrocarbons. Transformation of naphthalene by strain TSH1 which is able to use this two ring-polycyclic aromatic hydrocarbon (PAH) as a sole source of carbon and energy was investigated. The metabolic pathway was elucidated by identifying metabolites, biotransformation studies and monitoring enzyme activities in cell-free extracts. The identification of metabolites suggests that strain TSH1 initiates its attack on naphthalene by dioxygenation at its C-1 and C-2 positions to give 1,2-dihydro-1,2-dihydroxynaphthalene. The intermediate 2-hydroxycinnamic acid, characteristic of the meta-cleavage of the resulting diol was identified in the acidic extract. Apart from typical metabolites of naphthalene degradation known from mesophiles, benzoic acid was identified as an intermediate for the naphthalene pathway of this Nocardia strain. Neither phthalic acid nor salicylic acid metabolites were detected in culture extracts. Enzymatic experiments with cell extract showed the catechol 1,2-dioxygenase activity while transformation of phthalic acid and protocatechuic acid was not observed. The results of enzyme activity assays and identification of benzoic acid in culture extract provide strong indications that further degradation goes through benzoate and beta-ketoadipate pathway. Our results indicate that naphthalene degradation by thermophilic N. otitidiscaviarum strain TSH1 differs from the known pathways found for the thermophilic Bacillus thermoleovorans Hamburg 2 and mesophilic bacteria.

Alterations in serum levels of inflammatory cytokines (TNF, IL-1alpha, IL-1beta and IL-1Ra) 20 years after sulfur mustard exposure: Sardasht-Iran cohort study

Mustard gas, even in low doses, has the ability to inflict damage in multiple organs especially the skin, eyes, as well as the respiratory tract. This damage may cause many complications which persist during the lifespan of exposed subjects. Pro-inflammatory cytokines including TNF, IL-1alpha, IL-1beta and IL-1Ra cause systemic inflammatory reactions and numerous changes including altered cell signaling and migration, changes in cytokine production and fever. The aim of this study was to determine the serum levels of these cytokines in subjects who were exposed to mustard gas 20 years ago in comparison with an unexposed control group. In this historical cohort study 368 sulfur mustard (SM) exposed participants from Sardasht and 126 age-matched unexposed volunteers from Rabat (a nearby town) as controls were chosen by a random systematic sampling. The serum concentrations of IL-1alpha, IL-1beta, IL-1Ra and TNF were measured by a sandwich ELISA technique. Median of the serum levels of cytokines TNF, IL-1alpha, IL-1beta and IL-1Ra in the control group was 23.79, 1.89, 1.91 and 32.9 pg/ml respectively, while in the SM-exposed participants these values were 11.11, 0.81, 1.73 and 26.7 pg/ml respectively. The serum pro-inflammatory cytokine levels were significantly lower in the exposed group than in controls (p<0.01). There was also significant positive correlation between concentration of all of mentioned cytokines, the strongest being between IL-1beta and TNF (r=0.809 in the control group). The observed down-regulation of pro-inflammatory cytokines should be considered in interpretation of diagnosis and therapeutic measures taken to improve clinical complications.

The involvement of TLR2 in cytokine and reactive oxygen species (ROS) production by PBMCs in response to Leishmania major phosphoglycans (PGs).

In the present study, we show for the first time that lipophosphoglycan (LPG) stimulated cytokine production by human peripheral blood mononuclear cells is also mediated via Toll-like receptor (TLR2). In addition, in order to verify if TLR2 is involved in recognition of the purified PGs, neutralizing mAbs against TLR2 and TLR4 were used to treat the cells before being stimulated with PGs. We found strong Th1-promoting cytokines induced by sLPG but not by mLPG which was blocked by presence of anti-TLR2 mAb. This finding reveals a mechanism by which the first encounter and recognition of L. major promastigotes by mLPG after interaction with TLR2 provides a cytokine milieu for consequent Th2 differentiation. Moreover, having shown the strong induction of Th1-promoting cytokines and low production of IL-10 in response to sLPG might have vaccine implication since it is recognized by TLR2 providing signals to professional antigen presenting cells that reside in the skin to promote effective T cell responses against Leishmania infection. In addition, it was shown that purified mLPG and sLPG activate reactive oxygen species (ROS) production which is also blocked by anti-TLR2 but not by anti-TLR4. However, no inhibition was seen in PPG-induced cytokine and ROS production in the presence of anti-TLR2 and anti-TLR4, implying involvement of other receptors.

Synthesis and in vitro anti-leishmanial activity of 1-[5-(5-nitrofuran-2-yl)-1,3,4-thiadiazol-2-yl]- and 1-[5-(5-nitrothiophen-2-yl)-1,3,4-thiadiazol-2-yl]-4-aroylpiperazines.

The synthesis and anti-leishmanial activity of nitroheteroaryl-1,3,4-thiadiazole-based compounds including 1-[5-(5-nitrofuran-2-yl)-1,3,4-thiadiazol-2-yl]-4-aroylpiperazines and 1-[5-(5-nitrothiophen-2-yl)-1,3,4-thiadiazol-2-yl]-4-aroylpiperazines were described. Most of the synthesized compounds exhibited potent anti-leishmanial activity against both promastigote and amastigote forms of Leishmania major at non-cytotoxic concentrations. In general, 5-nitrofuran derivatives were more active than the corresponding 5-nitrothiophene analogues.

Novel antileishmanial chalconoids: Synthesis and biological activity of 1- or 3-(6-chloro-2H-chromen-3-yl)propen-1-ones

A series of novel chalconoids containing a 6-chloro-2H-chromen-3-yl group were prepared through a convenient and efficient synthetic method by using 5-chloro-2-hydroxybenzaldehyde as starting material. The target compounds were evaluated against the promastigote form of Leishmania major using MTT assay. All of the evaluated compounds have shown high in vitro antileishmanial activity at concentrations less than 3.0 microM. The results of cytotoxicity assessment against mouse peritoneal macrophage cells showed that these compounds display antileishmanial activity at non-cytotoxic concentrations.

Degradation of phenanthrene and anthracene by Nocardia otitidiscaviarum strain TSH1, a moderately thermophilic bacterium

Aims:  The metabolism of phenanthrene and anthracene by a moderate thermophilic Nocardia otitidiscaviarum strain TSH1 was examined.

Chromene‐Based Synthetic Chalcones as Potent Antileishmanial Agents: Synthesis and Biological Activity

Two types of regioisomeric chromene‐based chalcones namely, 1‐(6‐methoxy‐2H‐chromen‐3‐yl)‐3‐phenylpropen‐1‐ones and 3‐(6‐methoxy‐2H‐chromen‐3‐yl)‐1‐phenylpropen‐1‐ones were prepared and investigated for their antileishmanial activity against promastigotes form of Leishmania major. The obtained results from in vitro biological assays indicated that chloro‐substituted 1‐(6‐methoxy‐2H‐chromen‐3‐yl)‐3‐phenylpropen‐1‐ones exhibited excellent activity against Leishmania major at non‐cytotoxic concentrations.

Characterization of a moderate thermophilic Nocardia species able to grow on polycyclic aromatic hydrocarbons

Aims:  Our goal was the characterization of a new moderate thermophilic polycyclic aromatic hydrocarbon (PAH)‐utilizing Nocardia strain.