The central dogma of gene expression propounds that DNA is transcribed to mRNA and finally gets translated into protein. Only 2–3% of the genomic DNA is transcribed to protein-coding mRNA. Interestingly, only a further minuscule part of genomic DNA encodes for long non-coding RNAs (lncRNAs) which are characteristically more than 200 nucleotides long and can be transcribed from both protein-coding (e.g. H19 and TUG1) as well as non-coding DNA by RNA polymerase II. The lncRNAs do not have open reading frames (with some exceptions), 3`-untranslated regions (3’-UTRs) and necessarily these RNAs lack any translation-termination regions, however, these can be spliced, capped and polyadenylated as mRNA molecules. The flexibility of lncRNAs confers them specific 3D-conformations that eventually enable the lncRNAs to interact with proteins, DNA or other RNA molecules via base pairing or by forming networks. The lncRNAs play a major role in gene regulation, cell differentiation, cancer cell invasion and metastasis and chromatin remodeling. Deregulation of lncRNA is also responsible for numerous diseases in mammals. Various studies have revealed their significance as biomarkers for prognosis and diagnosis of cancer. The aim of this review is to overview the salient features, evolution, biogenesis and biological importance of these molecules in the mammalian system.

Agricultural airborne work exposures are complex in nature and workplace exposures are a risk for respiratory outcomes in workers. Endotoxin and glyphosate are two common agents in agricultural exposures. While endotoxin (lipopolysaccaride, LPS) is a potent inflammatory agent it explains only a portion of the respiratory inflammatory response. The inflammatory potential when LPS is presented with another common agricultural respiratory agent, glyphosate, is not known. Mice were assigned to four treatment groups: control, LPS alone, glyphosate alone, glyphosate and LPS combined. Treatments were for 1, 5 or 10 days. Five days of repeated exposure to the comintation of LPS and glyphosate resulted in higher neutrophil counts, myloperoxidase, TNF-α, IL-6, KC levels, and ICAM-1 and TLR-2 expression compared to the same length of treatment to LPS or glyphosate alone. After 10-days of exposure, inflammatory responses decreased, however leukocyte infiltration persisted along with increases in IL-4. Glyphosate exposure modified LPS induced lung inflammatory responses and TLR-2 may be important in the modulated inflammatory response.

Fipronil is an insecticide that acts at the gamma-aminobutyric acid receptor and glutamate-gated chloride channels in the central nervous systems of target organisms. The use of fipronil is increasing across the globe. Presently, very little data exist on the potential impact of exposure to fipronil on the lungs. We studied effects of intranasal (N = 8) and oral (N = 8) treatment with fipronil (10 mg/kg) on lungs of mice. Control mice were given groundnut oil orally (N = 7) or ethanol intranasally (N = 7) as these were the vehicles for respective treatments. Hematoxylin-eosin stained lung sections showed normal histology in the control lungs compared to the thickened alveolar septa, disruption of the airways epithelium and damage to vascular endothelium in the intranasal and the oral groups. Mice exposed to fipronil either orally or intranasally showed increased von Willebrand factor staining in the endothelium and septal capillaries. Compared to the control mice, TLR4 expression in airway epithelium was increased in mice treated intranasally but not orally with fipronil. Oral fipronil reduced TLR9 staining in the airway epithelium but intranasal exposure caused intense staining in the alveolar septa and airway epithelium. There were higher numbers of TLR4 positive cells in alveolar septa in lungs of mice treated intranasally (P = 0.010) compared to the respective control and orally treated mice but no significant differences between treatments for TLR9 positive stained cells (P = 0.226). The U937 macrophage cells exposed to fipronil at concentrations of 0.29 μm to 5.72 μm/ml over 3- or 24-hour showed significant increase in cell death at higher concentrations of fipronil (P < 0.0001). Western blots revealed no effect of fipronil on TLR4 (P = 0.49) or TLR9 (P = 0.94) expression on macrophage cell line. While both oral or intranasal fipronil treatments induced signs of lung inflammation, the number TLR4-positive septal cells was increased only following intranasal treatment. Fipronil causes macrophage cell death without altering TLR4 and TLR9 expression in vitro.

Pesticide residues in food and environment along with airborne contaminants like endotoxins pose a tangible threat to living beings. Fipronil, a broad-spectrum insecticide at acute doses in combination with endotoxin has been linked to airway inflammation. Wnt/PCP pathway plays important role in the pathogenesis of chronic inflammatory conditions by contributing to the release of downstream cytokines. However, there is no data on the PCP signaling pathway during fipronil-induced lung damage. This study aims to understand the molecular mechanisms underlying the pulmonary toxicity induced by fipronil alone or in combination with endotoxin. We used a microarray approach to obtain a global view of the transcriptional responses of the lungs exposed to fipronil and endotoxin in a mice model. Lung tissues were harvested from male Swiss albino mice (n=42) following long term oral exposure to high and low doses of fipronil alone or in combination with endotoxin. The differentially expressed genes were analyzed by Ingenuity pathway analysis software to predict the top canonical pathways. The microarray data for selected genes was validated using quantitative PCR and immunohistochemistry. Both BAL fluid and histopathology analysis suggested lung damage and altered transcriptomic profile of lung following exposure to high and low dose of fipronil with or without endotoxin. PCP pathway was among the top upregulated canonical pathways following exposure to both doses of fipronil individually or with LPS. Low dose of fipronil increased the expression of WNT-6, MAPK-8, IL-4 and IL-17C while higher dose decreased the expression of MAPK-8 and IL-17C. The expression data verified by realtime PCR was in concordance with microarray data. Long-term exposure to low (4.75 mg kg-1) and high (9.50 mg kg-1) dose of fipronil alone or in combination with endotoxins alters the histoarchitecture and transcriptome profile of lungs with the involvement of the PCP pathway. PCP pathway showed higher enrichment in low dose group of fipronil alone or in combination with LPS. The data from the study provides the insights of the potential damage on lungs caused by fipronil and endotoxin interaction and helps to better understand the mechanism of this complex relation.

Indoxacarb is commonly used to effectively control pests, cockroaches, termites, fleas, and houseflies. Although the toxicological profile of indoxacarb had already been well characterized, we examined the possible toxicological interaction with indoxacarb and endotoxin. Male Swiss albino mice aged 8-10 weeks were orally administered indoxacarb dissolved in groundnut oil at 4 mg/kg/day and 2 mg/kg/day for 90 days. On day 91, five animals from each group were challenged with lipopolysaccharides (LPS) at 80 µg/mouse, administered intranasally. Indoxacarb at 4 mg/kg significantly decreased Total leukocyte count, lymphocytopenia, and neutrophilia. Both doses of indoxacarb combined with LPS resulted in significant lymphocytopenia. Indoxacarb did not produce DNA damage in comet assay, but when combined with LPS, it resulted in a significant increase in tail length, tail moment, and olive moment. The data indicate that indoxacarb at 4 mg/kg administered orally for 90 days induced immune-response change. Further, both doses of indoxacarb, when combined with LPS, accelerate immunotoxicity and endotoxin-induced DNA damage.