Publications by authors named "S Iqbal"

1,320 Publications

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Nickel nanoparticles induce hepatotoxicity via oxidative and nitrative stress-mediated apoptosis and inflammation.

Toxicol Ind Health 2021 Sep 25:7482337211034711. Epub 2021 Sep 25.

Department of Analytical Chemistry and Instrumental Analysis, Institute of Sport- National Research Institute, Warsaw, Poland.

Nickel nanoparticles (Ni NPs) are utilized extensively in various industrial applications. However, there are increasing concerns about potential exposure to Ni NPs and consequent health effects. The aim of this study was to assess Ni NPs-induced liver toxicity in Sprague Dawley rats. Twenty-five rats were exposed to Ni NPs intraperitoneal injection at doses of 15, 30, and 45 mg/kg per body weight for 28 days. Results from ICP-MS analysis showed an increase in the concentration of Ni NPs in a dose-dependent manner. The liver dysfunction was indicated by considerable production of ALT, AST, ALP, LDH, and TB in Ni NPs-treated rats. Histological examination demonstrated liver injuries (inflammatory cells, congestion, necrosis, and pyknosis) in exposed rats with dose-dependent severity of pathologies by semi-quantitative histograding system. To explore the toxicological pathways, we examined oxidative stress biomarkers and detected Ni NPs significantly elevated the levels of MDA and LPO while decreasing the levels of CAT and GSH. All the changes in biomarkers were recorded in a dose-dependent relationship. In addition, we found upregulated NF-kβ indicating activation of inflammatory cytokines. ELISA results of serum revealed a remarkable increase of nitrative stress markers (iNOS and NO), ATPase activity, inflammatory cytokine (IL-6, IL-1β, and TNF-α), and apoptotic mediators (caspase-3 and caspase-9) in Ni NPs-treated groups than the control. In summary, the result of this study provided evidence of hepatotoxicity of Ni NPs and insightful information about the involved toxic pathways, which will help in health risk assessment and management, related preventive measures for the use of Ni-NPs materials.
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http://dx.doi.org/10.1177/07482337211034711DOI Listing
September 2021

Corrigendum: COVID-19 Vaccination: Concerns About Its Accessibility, Affordability, and Acceptability.

Front Med (Lausanne) 2021 7;8:749023. Epub 2021 Sep 7.

Department of Environmental Health, Centre for Public Health, Medical University of Vienna, Vienna, Austria.

[This corrects the article DOI: 10.3389/fmed.2021.647294.].
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http://dx.doi.org/10.3389/fmed.2021.749023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8454402PMC
September 2021

TLR-4 Agonist Induces IFN-γ Production Selectively in Proinflammatory Human M1 Macrophages through the PI3K-mTOR- and JNK-MAPK-Activated p70S6K Pathway.

J Immunol 2021 Sep 22. Epub 2021 Sep 22.

Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada;

IFN-γ, a proinflammatory cytokine produced primarily by T cells and NK cells, activates macrophages and engages mechanisms to control pathogens. Although there is evidence of IFN-γ production by murine macrophages, IFN-γ production by normal human macrophages and their subsets remains unknown. Herein, we show that human M1 macrophages generated by IFN-γ and IL-12- and IL-18-stimulated monocyte-derived macrophages (M0) produce significant levels of IFN-γ. Further stimulation of IL-12/IL-18-primed macrophages or M1 macrophages with agonists for TLR-2, TLR-3, or TLR-4 significantly enhanced IFN-γ production in contrast to the similarly stimulated M0, M2a, M2b, and M2c macrophages. Similarly, M1 macrophages generated from COVID-19-infected patients' macrophages produced IFN-γ that was enhanced following LPS stimulation. The inhibition of M1 differentiation by Jak inhibitors reversed LPS-induced IFN-γ production, suggesting that differentiation with IFN-γ plays a key role in IFN-γ induction. We subsequently investigated the signaling pathway(s) responsible for TLR-4-induced IFN-γ production in M1 macrophages. Our results show that TLR-4-induced IFN-γ production is regulated by the ribosomal protein S6 kinase (p70S6K) through the activation of PI3K, the mammalian target of rapamycin complex 1/2 (mTORC1/2), and the JNK MAPK pathways. These results suggest that M1-derived IFN-γ may play a key role in inflammation that may be augmented following bacterial/viral infections. Moreover, blocking the mTORC1/2, PI3K, and JNK MAPKs in macrophages may be of potential translational significance in preventing macrophage-mediated inflammatory diseases.
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http://dx.doi.org/10.4049/jimmunol.2001191DOI Listing
September 2021

Cigarette smokers' perceptions of smoking cessation and associated factors in Karachi, Pakistan.

Public Health Nurs 2021 Sep 21. Epub 2021 Sep 21.

College of Nursing, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.

Objectives: The study explored the perceptions of adult smokers with cardiovascular and respiratory diseases regarding cigarette smoking cessation. We also explored factors that may hinder or facilitate smoking cessation process.

Design: Qualitative descriptive exploratory design SAMPLE: Purposive sample of 13 adult smokers with cardiovascular or respiratory diseases visiting outpatient cardiac and respiratory clinics at a private tertiary care hospital MEASUREMENTS: In-depth, face-to-face, and semi-structured interviews were conducted. The interviews were digitally recorded and transcribed verbatim followed by a six steps process of manual thematic analysis of data.

Results: Meaningful statements were assigned codes and grouped into categories. Categories were clustered under three themes representing individual factors, socio-cultural factors, and institutional factors.

Conclusions: Smoking cessation is influenced by personal, cultural, as well as social aspects. Institutionally, there is a need to recognize that smoking is a learned behavior; hence, prohibiting public smoking will potentially contribute to non-smoking behaviors. Although the nature of misconceptions varies, this is imperative to ensure consistency in messaging, programming, and supports led by healthcare professionals.
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http://dx.doi.org/10.1111/phn.12971DOI Listing
September 2021

Critical Evaluation of Different Lysosomal Labeling Methods Used to Analyze RNA Nanocarrier Trafficking in Cells.

Bioconjug Chem 2021 Sep 20. Epub 2021 Sep 20.

Department of Biomedical Engineering, University of Delaware, 161 Colburn Lab, Newark, Delaware 19716, United States.

The use of nucleic acids to regulate gene expression is a rapidly developing field with immense clinical potential. Nanomaterials are frequently used to deliver nucleic acids into cells as they can overcome the poor cellular uptake and endo/lysosomal degradation of bare nucleic acids. For these nanocarriers to be effective, they must escape endo/lysosomal compartments to deliver their nucleic acid cargo into the cytosol (for ribonucleic acid (RNA)) or nucleus (for deoxyribonucleic acid (DNA)). This process is poorly understood and remains an area of active research toward the goal of developing effective delivery strategies. Fluorescent endo/lysosomal markers are among the most widely employed tools used to evaluate the endosomal escape of nucleic acid nanocarriers. However, the endo/lysosomal labeling method may alter the extent of and route of nanocarrier uptake by cells. The impact of these markers on cellular function and cell-nanocarrier interactions has not been probed in a systematic manner. To investigate this, we compared the effects of several common lysosomal labeling methods, namely, LysoTracker Red (LT Red), transient lysosomal-associated membrane protein 1-mutant green fluorescent protein (LAMP1-mGFP) transfection (Transient GFP), and stable lentiviral LAMP1-mGFP transfection (Stable GFP), on cellular metabolic activity, nanocarrier uptake, nanocarrier/lysosomal label colocalization, and gene silencing potency in U87 glioblastoma and MDA-MB-231 breast cancer cells using polyethyleneimine (PEI)/ribonucleic acid (RNA) polyplexes as a model nanocarrier. In both U87s and MDA-MB-231s, Transient GFP and LT Red labeling reduced metabolic activity relative to untransfected (Parental) cells, while Stable GFP labeling increased metabolic activity. Congruently, flow cytometry indicates Stable GFP cells have greater polyplex uptake than LT Red-labeled cells in both cell lines. Despite these similar trends in uptake, polyplex intracellular trafficking differs in the two cell lines, as confocal imaging revealed greater polyplex/lysosome colocalization in Stable GFP U87 cells than LT Red-labeled U87 cells, while the trend was reversed in MBA-MB-231s. The level of RNA-mediated gene silencing achieved in Parental versus Stable GFP U87 and MDA-MB-231 cells agreed with the observed levels of polyplex/lysosome colocalization, supporting the established concept that endosomal escape is the rate-limiting step for RNA interference. These findings indicate that lysosomal labels can profoundly alter cellular function and cell-nanocarrier interactions, presenting critical new considerations for researchers investigating nanoparticle trafficking.
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http://dx.doi.org/10.1021/acs.bioconjchem.1c00405DOI Listing
September 2021
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