Cytokine Storm Syndrome in Covid-19 Patients: Characteristics and Diagnosis

Cytokine storm syndrome (CSS) is a critical condition induced by a cascade of cytokine activation, characterized by overwhelming systemic inflammation, hyperferritinaemia, haemodynamic instability and multiple organ failure. At the end of 2019, the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, and rapidly developed into a global pandemic. There is a dramatic increase of inflammatory cytokines in patients with COVID-19, suggesting the existence of cytokine storm in some critical illness patients. Here, we summarize the p

The Role of the Human Immune System in the Aging Process: a Mathematical Model of Cell and Cytokine Activation

The role of the human immune system as a factor in the aging process has led to extensive research in the field of infection biology and bioinformatics. Cell-based mathematical models have previously been used to simulate the immune system in response to pathogens. A variety of cells, such as activated and resting macrophages, plasma cells, antibodies, helper T cells, T-lymphocytes, and B-lymphocytes, have already been simulated by mathematical models. This work aims to incorporate cytokines in these mathematical models to create a more comprehensive simulation that can predict cytokine levels in response to a Gram-positive bacterium, S. aureus. To accomplish this, the cytokines Tumor Necrosis Factor Alpha (TNF-𝛼), Interleukin 6 (IL-6), Interleukin 8 (IL-8), and Interleukin 10 (IL-10) were studied to quantify the relationship between cytokine release from macrophages and the concentration of the pathogen, S. aureus ex vivo. The results of the simulation were compared to ex vivo human whole blood data to test its accuracy. The future expansion of this model may provide a clearer image of the various interactions within the immune system and this improved model of the immune system may also facilitate a better understanding of the mechanisms that lead to the degradation of the immune system during the aging process.

Identification of Cell Surface Molecules That Determine the Macrophage Activation Threshold Associated With an Early Stage of Malignant Transformation

The ability of immune cells to sense changes associated with malignant transformation as early as possible is likely to be important for the successful outcome of cancer immunosurveillance. In this process, the immune system faces a trade-off between elimination of cells harboring premalignant or malignant changes, and autoimmune pathologies. We hypothesized that the immune system has therefore evolved a threshold for the stage of transformation from normal to fully malignant cells that first provides a threat (danger) signal requiring a response. We co-cultured human macrophages with a unique set of genetically related human cell lines that recapitulate successive stages in breast cancer development: MCF10A (immortalized, normal); MCFNeoT (benign hyperplasia); MCFT1 (atypical hyperplasia); MCFCA1 (invasive cancer). Using cytokines-based assays, we found that macrophages were inert towards MCF10A and MCFNeoT but were strongly activated by MCFT1 and MCFCA1 to produce inflammatory cytokines, placing the threshold for recognition between two premalignant stages, the earlier stage MCFNeoT and the more advanced MCFT1. The cytokine activation threshold paralleled the threshold for enhanced phagocytosis. Using proteomic and transcriptomic approaches, we identified surface molecules, some of which are well-known tumor-associated antigens, that were absent or expressed at low levels in MCF10A and MCFNeoT but turned on or over-expressed in MCFT1 and MCFCA1. Adding antibodies specific for two of these molecules, Annexin-A1 and CEACAM1, inhibited macrophage activation, supporting their role as cancer “danger signals” recognized by macrophages.

Cytokine induced natural killer cell training is dependent on cellular metabolism and is defective in obesity

Natural killer (NK) cells are a population of innate immune cells which can rapidily kill cancer cells and produce cytokines such as interferon gamma (IFN-gamma). A key feature of NK cells is their ability to respond without prior sensitation, however it is now well established that NK cells can possess memory-like features. After activation with cytokines, NK cells demonstrate enhanced effector functions upon restimulation days or weeks later. This demonstrates that NK cells may be "trained" to be more effective killers and harnessed as more potent cancer immunotherapy agents. We have previously demonstrated that cellular metabolism is essential for NK cell responses, with NK cells upregulating both glycolysis and oxidative phosphorylation upon cytokine stimulation. Limiting NK cell metabolism results in reduced cytotoxicity and cytokine production. We have also demonstrated that defective NK cell responses in obesity are linked to defective cellular metabolism. In the current study we investigated if cellular metabolism is required during the initial period of NK cell cytokine training, and if NK cells from people with obesity (PWO) can be effectively trained. We show that increased flux through glycolysis and OXPHOS during the initial cytokine activation period is essential for NK cell training, as is the metabolic signalling factor Srepb. We show that NK cells from PWO, which are metabolically defective, display impaired NK cell training, which may have implications for immunotherapy in this particularly vulnerable group.

Environmental Pollutants, Mucosal Barriers, and Pathogen Susceptibility; The Case for Aflatoxin B1 as a Risk Factor for HIV Transmission and Pathogenesis

HIV transmission risk is dependent on the infectivity of the HIV+ partner and personal susceptibility risk factors of the HIV− partner. The mucosal barrier, as the internal gatekeeper between environment and self, concentrates and modulates the internalization of ingested pathogens and pollutants. In this review, we summarize the localized effects of HIV and dietary toxin aflatoxin B1 (AFB1), a common pollutant in high HIV burden regions, e.g., at the mucosal barrier, and evidence for pollutant-viral interactions. We compiled literature on HIV and AFB1 geographic occurrences, mechanisms of action, related co-exposures, personal risk factors, and HIV key determinants of health. AFB1 exposure and HIV sexual transmission hotspots geographically co-localize in many low-income countries. AFB1 distributes to sexual mucosal tissues generating inflammation, microbiome changes and a reduction of mucosal barrier integrity, effects that are risk factors for increasing HIV susceptibility. AFB1 exposure has a positive correlation to HIV viral load, a risk factor for increasing the infectivity of the HIV+ partner. The AFB1 exposure and metabolism generates inflammation that recruits HIV susceptible cells and generates chemokine/cytokine activation in tissues exposed to HIV. Although circumstantial, the available evidence makes a compelling case for studies of AFB1 exposure as a risk factor for HIV transmission, and a modifiable new component for combination HIV prevention efforts.

Human - murine concordance of molecular signatures in nerve-sparing murine partial bladder outlet obstruction (NeMO)

Recently we demonstrated the utility of a nerve-sparing mid-urethra model of partial outlet obstruction (NeMO) that has high consistency and minimal mortalities, unlike the traditional model proximal to the bladder neck. Our goal was to uncover potential therapeutic targets by investigating the genome wide transcriptional changes and pathways altered in NeMO to compare with published human bladder obstruction data. We performed RNAseq and analysed the differentially upregulated and downregulated genes for associated pathways, transcription factor binding site analysis (TFBS), upstream regulators and Gene Set Enrichment Analysis (GSEA). NeMO increased bladder mass, relative bladder mass and hyperactivity, and decreased voiding efficiency. In NeMO vs. sham, 831 genes were differentially expressed (adjusted p<0.05) and correlated significantly with at least one physiologic parameter. Gene ontology revealed an enrichment for matrix pathways in the upregulated genes, and for cardiac contraction, oxidative phosphorylation and pyruvate metabolism in downregulated genes. TFBS analysis revealed a differential regulation of up vs downregulated genes, with KLF4 strongly associated with the downregulated genes. Downregulated genes of Human bladder obstruction were also associated with the TFBS of KLF4. GSEA of the NeMO gene set confirmed the DAVID results, but also showed a cluster of cytokine activation genes. In human bladder underactive obstruction, cytokines were also highly upregulated. The common cytokine pathway upregulation provided an example of the use of RNAseq for uncovering potential new therapeutic targets. As TNF and the innate immune pathways were strongly implicated in both human and mouse, and TNF is produced by macrophages, we depletion macrophages with clodronate (CL) during NeMO. Although CL did not block hypertrophy, it significantly decreased NeMO-induced hyperactive voiding (p<0.01) and increased voiding efficiency (p<0.05). The expression of several cytokines/chemokines correlated significantly with bladder functional parameters such as residual volumes, and hyperactivity. Conclusions: Gene expression signatures of NeMO were consistent with human bladder obstruction, supporting the use of the nerve-sparing mouse obstruction model for therapeutic exploration.

Three-Dimensional Aggregated Spheroid Model of Hepatocellular Carcinoma Using a 96-Pillar/Well Plate

A common method of three-dimensional (3D) cell cultures is embedding single cells in Matrigel. Separated cells in Matrigel migrate or grow to form spheroids but lack cell-to-cell interaction, which causes difficulty or delay in forming mature spheroids. To address this issue, we proposed a 3D aggregated spheroid model (ASM) to create large single spheroids by aggregating cells in Matrigel attached to the surface of 96-pillar plates. Before gelling the Matrigel, we placed the pillar inserts into blank wells where gravity allowed the cells to gather at the curved end. In a drug screening assay, the ASM with Hepatocellular carcinoma (HCC) cell lines showed higher drug resistance compared to both a conventional spheroid model (CSM) and a two-dimensional (2D) cell culture model. With protein expression, cytokine activation, and penetration analysis, the ASM showed higher expression of cancer markers associated with proliferation (p-AKT, p-Erk), tight junction formation (Fibronectin, ZO-1, Occludin), and epithelial cell identity (E-cadherin) in HCC cells. Furthermore, cytokine factors were increased, which were associated with immune cell recruitment/activation (MIF-3α), extracellular matrix regulation (TIMP-2), cancer interaction (IL-8, TGF-β2), and angiogenesis regulation (VEGF-A). Compared to CSM, the ASM also showed limited drug penetration in doxorubicin, which appears in tissues in vivo. Thus, the proposed ASM better recapitulated the tumor microenvironment and can provide for more instructive data during in vitro drug screening assays of tumor cells and improved prediction of efficacious drugs in HCC patients.

Integrins: An Important Link between Angiogenesis, Inflammation and Eye Diseases

Integrins belong to a group of cell adhesion molecules (CAMs) which is a large group of membrane-bound proteins. They are responsible for cell attachment to the extracellular matrix (ECM) and signal transduction from the ECM to the cells. Integrins take part in many other biological activities, such as extravasation, cell-to-cell adhesion, migration, cytokine activation and release, and act as receptors for some viruses, including severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). They play a pivotal role in cell proliferation, migration, apoptosis, tissue repair and are involved in the processes that are crucial to infection, inflammation and angiogenesis. Integrins have an important part in normal development and tissue homeostasis, and also in the development of pathological processes in the eye. This review presents the available evidence from human and animal research into integrin structure, classification, function and their role in inflammation, infection and angiogenesis in ocular diseases. Integrin receptors and ligands are clinically interesting and may be promising as new therapeutic targets in the treatment of some eye disorders.