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Gold nanoparticles (AuNPs) possess considerable biocompatibility and therefore gaining more attention for their biomedical applications. Previous studies have shown the transient increase in pro-inflammatory cytokines expression in different organs of rats and mice exposed to AuNPs. Structural changes in the spleen of mice treated with AuNPs have also been reported. This investigation was aimed to study the immunostaining of IL-1β, IL-6 and TNF-α in mice treated with different sizes of AuNPs. The animals were divided into 7 groups of 4 animals in each group. One group received saline and served as control. Two sets of three groups were treated with 5 nm, 20 nm and 50 nm diameter AuNPs. One set was sacrificed on day 1 and the other on day 7 following the AuNPs injections. Spleens were dissected out and promptly fixed in formalin for 3 days and then processed for IL-1β, IL-6 and TNF-α immunostaining using target-specific antibodies. The immunoreactivities of IL-1β and IL-6 were increased with the increase of AuNP size. The immunostaining of IL-1β in spleen of 20 nm AuNP treated mice was subsequently decreased on day 7 whereas it persisted in 50 nm AuNP group. The increase in the immunoreactivity of IL-6 on day 1 was decreased on day 7 in the spleens of mice treated with 20 nm or 50 nm AuNPs. The immunostaining of TNF-α was found to be negative in all the treatment groups. In conclusion, the size of AuNPs plays an important role in the expression of proinflammatory cytokines in mouse spleen; small size (5 nm) AuNPs caused minimal effect, whereas larger (50 nm) AuNPs produced intense immunostaining. Keywords: Gold nanoparticles, Spleen, Immunohistochemistry, Cytokines, Inflammation

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a recent pandemic outbreak threatening human beings worldwide. This novel coronavirus disease-19 (COVID-19) infection causes severe morbidity and mortality and rapidly spreading across the countries. Therefore, there is an urgent need for basic fundamental research to understand the pathogenesis and druggable molecular targets of SARS-CoV-2. Recent sequencing data of the viral genome and X-ray crystallographic data of the viral proteins illustrate potential molecular targets that need to be investigated for structure-based drug design. Further, the SARS-CoV-2 viral pathogen isolated from clinical samples needs to be cultivated and titrated. All of these scenarios demand suitable laboratory experimental models. The experimental models should mimic the viral life cycle as it happens in the human lung epithelial cells. Recently, researchers employing primary human lung epithelial cells, intestinal epithelial cells, experimental cell lines like Vero cells, CaCo-2 cells, HEK-293, H1299, Calu-3 for understanding viral titer values. The human iPSC-derived lung organoids, small intestinal organoids, and blood vessel organoids increase interest among researchers to understand SARS-CoV-2 biology and treatment outcome. The SARS-CoV-2 enters the human lung epithelial cells using viral Spike (S1) protein and human angiotensin-converting enzyme 2 (ACE-2) receptor. The laboratory mouse show poor ACE-2 expression and thereby inefficient SARS-CoV-2 infection. Therefore, there was an urgent need to develop transgenic hACE-2 mouse models to understand antiviral agents’ therapeutic outcomes. This review highlighted the viral pathogenesis, potential druggable molecular targets, and suitable experimental models for basic fundamental research.

C4b Binding Protein (C4BP) is a major fluid phase inhibitor of the classical and lectin pathways of the complement system. Complement inhibition is achieved by binding to and restricting the role of activated complement component C4b. C4BP functions as a co-factor for factor I in proteolytic inactivation of both soluble and cell surface-bound C4b, thus restricting the formation of the C3-convertase, C4b2a. C4BP also accelerates the natural decay/dissociation of the C3 convertase. This makes C4BP a prime target for exploitation by pathogens to escape complement attack, as seen in Streptococcus pyogenes or Flavivirus. Here, we examined whether C4BP can act on its own in a complement independent manner, against pathogens. C4BP bound H1N1 and H3N2 subtypes of Influenza A Virus (IAV) most likely via multiple sites in Complement Control Protein (CCP) 1-2, 4-5, and 7-8 domains of its α-chain. In addition, C4BP CCP1-2 bound H3N2 better than H1N1. C4BP bound three IAV envelope proteins: Haemagglutinin (~70 kDa), Neuraminidase (~55 kDa), and Matrix protein 1 (~25kDa). C4BP suppressed H1N1 subtype infection into the lung epithelial cell line, A549, while it promoted infection by H3N2 subtype. C4BP restricted viral entry for H1N1 but had the opposite effect on H3N2, as evident from experiments using pseudo-typed viral particles. C4BP downregulated mRNA levels of pro-inflammatory IFN-α, IL-12, and NFκB in the case of H1N1, while it promoted a pro-inflammatory immune response by upregulating IFN- α, TNF-α, RANTES, and IL-6 in the case of H3N2. We conclude that C4BP differentially modulates the efficacy of IAV entry, and hence, replication in a target cell in a strain-dependent manner, and acts as an entry inhibitor for H1N1. Thus, CCP containing complement proteins such as factor H and C4BP may have additional defense roles against IAV that do not rely on the regulation of complement activation.

© 2021 Mangogna, Varghese, Agostinis, Alrokayan, Khan, Stover, Belmonte, Martorana, Ricci, Bulla and Kishore. The complement system is readily triggered by the presence of damage-associated molecular patterns on the surface of tumour cells. The complement alternative pathway provides rapid amplification of the molecular stress signal, leading to complement cascade actvation to deal with pathogens or malignant cells. Properdin is the only known positive regulator of the alternative pathway. In addition, properdin promotes the phagocytic uptake of apoptotic T cells by macrophages and dendritic cells without activating the complement system, thus, establishing its ability to recognize “altered-self”. Dysregulation of properdin has been implicated in a range of pathology, leading to substantial tissue damage in the host, and in some cases, to chronic unresolved inflammation. A corollary of this may be the development of cancer. Hence, to establish a correlation between properdin presence/levels in normal and cancer tissues, we performed bioinformatics analysis, using Oncomine and UALCAN. Survival analyses were performed using UALCAN and PROGgeneV2 to assess if properdin can serve as a potential prognostic marker for human lung adenocarcinoma (LUAD), liver hepatocellular carcinoma (LIHC), cervical squamous cell carcinoma (CESC), and pancreatic adenocarcinoma (PAAD). We also analysed levels of tumour-infiltrating immune cells using TIMER, a tool for characterizing immune cell composition in cancers. We found that in LUAD and LIHC, there was a lower expression of properdin in the tumours compared to normal tissues, while no significant difference was observed in CESC and PAAD. Survival analysis demonstrated a positive association between properdin mRNA expression and overall survival in all 4 types of cancers. TIMER analysis revealed that properdin expression negatively correlated with tumour purity and positively correlated with levels of infiltrating B cells, cytotoxic CD8+ T cells, CD4+ helper T cells, macrophages, neutrophils and dendritic cells in LUAD, CESC and PAAD, and with levels of B cells, CD8+ T cells and dendritic cells in LIHC. Immunohistochemical analysis revealed that infiltrating immune cells are the most likely source of properdin in the tumour microenvironment. Thus, complement protein properdin shows promise as a prognostic marker in cancer and warrants further study. Italian Ministry of Health (RC 20/2016- Institute for Maternal and Child Health IRCCS Burlo Garofolo, Trieste, Italy); International Scientific Partnership Programme (ISPP) at the King Saud University, Riyadh (ISPP -145).

Copyright © 2020 Murugaiah, Varghese, Saleh, Tsolaki, Alrokayan, Khan, Collison, Sim, Nal, Al-Mohanna and Kishore. The complement system is an ancient innate immune defence mechanism that can recognise molecular patterns on the invading pathogens. Factor H, as an inhibitor of the alternative pathway, down-regulates complement activation on the host cell surface. Locally synthesised factor H at the site of infection/injury, including lungs, can act as a pattern recognition molecule without involving complement activation. Here, we report that factor H, a sialic acid binder, interacts with influenza A virus (IAV) and modulates IAV replication, as observed by an upregulation of matrix protein 1 (M1) expression in H3N2-infected A549 cells, while downregulating M1 in H1N1 subtype-infected cells. Far-western blot revealed that factor H binds hemagglutinin (HA, ~70kDa), neuraminidase (NA, ~60kDa), and M1 (~25kDa). IAV-induced transcriptional levels of IFN-α, TNF-α, IL-12, IL-6, IFN-α, while RANTES were reduced following factor H treatment for the H1N1 subtype at 6 h post-infection. However, for the H3N2 subtype, mRNA levels of these pro-inflammatory cytokines were enhanced. Recombinant form of vaccinia virus complement control protein (VCP), which like factor H, contains CCP modules and has complement-regulatory activity, mirrored the results obtained with factor H. Both factor H (25%) and VCP (45%) were found to reduce luciferase reporter activity in MDCK cells transduced with H1N1 pseudotyped lentiviral particles. Factor H (50%) and VCP (30%) enhanced the luciferase reporter activity for H3N2, suggesting an entry inhibitory role of factor H and VCP against H1N1, but not H3N2. Thus, factor H can modulate IAV infection and inflammatory response independent of its complement-related functions. King Saud University, Riyadh, International Scientific Partnership Programme (ISPP) ISPP-145.

The present study was designed to explore the neuroprotective properties of Aconitum napellus (Ranunculaceae). The plant detoxification was done using either water, or cow or goat milk as per the Ayurvedic shodhana method. The evaluation of the neuroprotective role of A. napellus was performed on diabetic neuropathy induced by streptozotocin in Sprague Dawley (SD) rats. Body mass, blood sugar level, oral glucose tolerance test, hyperalgesia, cold allodynia, motor co-ordination test, and locomotor activity, oxidative biomarkers (TBARS, reduced glutathione, catalase and superoxide dismutase) and sciatic nerve histomorphology were assessed. The in vitro studies were done on human neuroblastoma cell line SHSY-5Y and used an MTT assay to assess the antiproliferative activity of different extracts. Results suggest that the goat milk treated chloroform extract has less percentage of aconitine. After administration of the detoxified chloroform extract to the diabetic animals, there was a significant improvement in the myelination and degenerative changes of the nerve fibers along with behavioral changes (p &lt, 0.05 as compared with diabetic control group). The findings of the in vitro research show an effective neuroprotective role of A. napellus. This suggests that A. napellus should be further investigated for its effect in diabetic pathology.

Lead (Pb) toxicity has a great impact in terms of toxicity towards living organisms as it severely affects crop growth, yield, and food security, thus, warranting appropriate measures for the remediation of Pb polluted soils. Phytoextraction of heavy metals (HMs) using tolerant plants along with organic chelators has gained global attention. Thus, this study examines the possible influence of citric acid (CA) on unveiling the potential phytoextraction of Pb by using castor beans. For this purpose, different levels of Pb (0, 300, 600 mg kg&minus, 1 of soil) and CA (0, 2.5, and 5 mM) were supplied alone and in all possible combinations. The results indicate that elevated levels of Pb (especially 600 mg kg&minus, 1 soil) induce oxidative stress, including hydrogen peroxide (H2O2) and malanodialdehyde (MDA) production in plants. The Pb stress reduces the photosynthetic traits (chlorophyll and gas exchange parameters) in the tissues of plants (leaves and roots), which ultimately lead to a reduction in growth as well as biomass. Enzyme activities such as guaiacol peroxidase, superoxide dismutase, ascorbate peroxidase, and catalase are also linearly increased in a dose-dependent manner under Pb stress. The exogenous application of CA reduced the Pb toxicity in plants by improving photosynthesis and, ultimately, plant growth. The upsurge in antioxidants against oxidative stress shows the potential of CA-treated castor beans plants to counteract stress injuries by lowering H2O2 and MDA levels. From the results of this study, it can be concluded that CA treatments play a promising role in increasing the uptake of Pb and reducing its phytotoxicity. These outcomes recommend that CA application could be an effective approach for the phytoextraction of Pb from polluted soils by growing castor beans.

Gold nanoparticles (GNPs) possess promising applications in targeted drug delivery and controlled release of a variety of chemical agents. However, the immunocompatibility of GNPs is poorly understood. After exposure, GNPs preferentially tend to accumulate is liver, where they induce an acute phase proinflammatory response. We therefore compared the two techniques, immunohistochemistry and real-time PCR for measuring the protein and mRNA expressions of IL-1β, IL-6 and TNF-α in liver of rats after intraperitoneal injections (5μg/animal) of 10 and 50nm diameter GNPs for 1 and 5days. The results showed that both 10nm and 50nm GNPs induced an acute phase expression of proinflammatory cytokines that receded on day 5. The proinflammatory response on day 1 was comparatively more severe with 50nm GNPs than 10nm GNPs. A comparative evaluation between immunostaining and real-time PCR showed that the latter technique is more sensitive as it could detect the cytokines mRNA expression in control samples as well. This could be partly attributed to the amplification strategy used in real-time PCR and partly to the variations in the half lives of cytokines mRNA and their resulting proteins.