The cytokine storm in COVID-19: Further advances in our understanding the role of specific chemokines involved

SARS-COV-2 infection represents the greatest pandemic of the world, counting daily increasing number of subjects positive to the virus and, sadly, increasing number of deaths. Current studies reported that the cytokine/chemokine network is crucial in the onset and maintenance of the “cytokine storm”, the event occurring in those patients in whom the progression of COVID-19 will progress, in most cases, to a very severe and potentially threatening disease. Detecting a possible “immune signature” in patients, as assessed by chemokines status in patients with COVID-19, could be helpful for individual risk stratification for developing a more or less severe clinical course of the disease. The present review is specifically aimed at overviewing current evidences provided by in vitro and in vivo studies addressing the issue of which chemokines seems to be involved, at least at present, in COVID-19. Currently available experimental and clinical studies regarding those chemokines more deeply studied in COVID-19, with a specific focus on their role in the cytokine storm and ultimately with their ability to predict the clinical course of the disease, will be taken into account. Moreover, similarities and differences between chemokines and cytokines, which both contribute to the onset of the pro-inflammatory loop characterizing SARS-COV-2 infection, will be briefly discussed. Future studies will rapidly accumulate in the next months and their results will hopefully provide more insights as to the complex physiopathology of COVID-19-related cytokine storm. This will likely make the present review somehow “dated” in a short time, but still the present review provides an overview of the scenario of the current knowledge on this topic.     

Special ergolines efficiently inhibit the chemokine receptor CXCR3 in blood

The structure-activity relationship of highly potent special ergolines which selectively block the chemokine receptor CXCR3 is reported. The most potent compounds showed IC₅₀ values below 10 nM in both ligand binding and Ca²⁺-mobilization assays. However, these compounds were poorly active in an assay that measures receptor occupancy in blood. Introduction of polar substituents led to derivatives with IC₅₀ values below 10 nM in this assay. Among them was compound 11a which showed both a favorable PK profile and cross reactivity with rodent CXCR3 making it a promising tool compound to further explore the role of CXCR3 in animal models.     

Expression of IFN-gamma induced CXCR3 agonist chemokines and compartmentalization of CXCR3+ cells in the periphery and lymph nodes of rhesus macaques during simian immunodeficiency virus infection and acquired immunodeficiency syndrome

Dysregulation of cytokines and chemokines during human immunodeficiency virus 1 (HIV-1) and simian immunodeficiency virus (SIV) infection is thought to be critical in the progression of acquired immunodeficiency syndrome (AIDS). To evaluate the potential role of Th1-agonist chemokines in disease progression during AIDS, we assessed CXCL9/MIG and CXCL10/IP-10 expression simultaneously in the periphery and lymphoid tissues of SIV-infected animals at a single-cell level by flow cytometry. We optimized intracellular staining and analysis of CXCL9/MIG and CXCL10/IP-10 production in human leukocyte antigen (HLA)-DR+ macaque cells by flow cytometry using cross-reactive antibodies against human chemokines. We observed an upregulation of CXCL9/MIG and CXCL10/IP-10 production in both the periphery and lymph nodes of infected animals compared with na?ve controls. Animals with higher viral loads had higher levels of CXCL9/MIG and CXCL10/IP-10 producing cells compared with animals with low viral loads. Analysis of cells bearing the receptor (CXCR3) for CXCL9/MIG and CXCL10/IP-10 revealed increased number of CXCR3+ cells in the lymph nodes of infected animals. Importantly, an inverse correlation (P < 0.05) between CXCL9/MIG and CXCL10/IP-10 production, both in the periphery and lymph nodes, and peripheral CD4+ T-cell numbers was observed. These findings provide further evidence that dysregulation of Th1 agonist chemokines might contribute to the ultimate immunopathology during AIDS.     

L-Arginine modulates CXC chemokines in the human intestinal epithelial cell line HCT-8 by the NO pathway

Arginine has immunomodulating properties in different animal models but its effects in human intestine remain unknown. This study examined whether arginine modulates inflammatory mediators as chemokines and nitric oxide (NO) in the human intestinal epithelial cell line HCT-8 induced by cytokines. Under basal conditions, arginine did not influence iNOS protein expression, NO and chemokine production and mRNA levels (P>0.05 for all). Stimulation with cytokines-induced a significant increase of NO and chemokine production, iNOS and chemokine mRNA level and iNOS protein expression. Under inflammatory conditions, arginine increased 30% NO production (P<0.05) but did not influence iNOS mRNA level or iNOS protein expression. Under stimulated conditions, arginine decreased IL-8 and Mig mRNA level (57% and 39%, for 0.1 vs. 2 mmol/l l-arginine, P<0.05, respectively), and production (respectively, 28 and 23%, both P<0.05). IP-10 and I-TAC mRNA level and production were not significantly influenced by arginine. Under inflammatory conditions, l-arginine as well as a NO donor (sodium nitroprusside (SNP)) increased NO production, which was inversely correlated with IL-8 production (r'=-0.66, P=0.007 for arginine; r'=-0.79, P<0.0001 for SNP). Use of NG-Methyl-l-arginine acetate, a NOS inhibitor which prevents arginine-induced NO production, suppressed the arginine-induced IL-8 inhibition (P<0.05). In HCT-8 cells, arginine enhanced cytokine-induced NO production, reduced IL-8 and Mig production and mRNA level and had no effects on other assessed chemokines. In conclusion, arginine-induced IL-8 inhibition in HCT-8 cells involves NO pathway under inflammatory conditions. These data suggest that arginine-enriched enteral nutrition may have significant influence on inflammatory response in human intestine.     

Cleavage of chemokines CCL2 and CXCL10 by matrix metalloproteinases-2 and -9: Implications for chemotaxis

Proteolytic processing of chemokines is a complex process that can result in dramatic effects on their chemotactic activity. Results from gel electrophoresis and mass spectrometry using recombinant CCL2 and CXCL10, incubated with either MMP-2 or -9, indicate that both chemokines are cleaved by the enzymes. N-terminal truncation of four amino acids from CCL2, and four or five residues from CXCL10 occurred, but removal of four residues from the C-terminus of CXCL10 was also observed with both MMPs. The speed of the reaction was chemokine-dependent, with N-terminal processing of CCL2 being complete within 3 h, whereas activity of the MMPs on CXCL10 remained incomplete at 48 h. The effect on the chemotactic potential of N-terminal truncation of CCL2 by MMPs-2 and -9 was investigated using in vitro migration assays. Monocytic cells exhibited a 2-fold reduction in migration to MMP-cleaved CCL2 variants, compared to intact CCL2.     

CD4+ T cell migration into the cornea is reduced in CXCL9 deficient but not CXCL10 deficient mice following herpes simplex virus type 1 infection

The role of CXCL9 and CXCL10 in the ocular immune response to herpes simplex virus type 1 (HSV-1) infection was investigated using mice deficient in either CXCL9 or CXCL10. CXCL10 but not CXCL9 deficient mice showed an increase in sensitivity to ocular virus infection as measured by an elevation in virus titer recovered in the tear film and corneal tissue. The increase in virus was associated with an increase in the expression of the chemokine CCL2 but no significant change in the infiltration of CD4(+) T cells or NK cells into the corneal stroma. In contrast, a significant reduction in CD4(+) T cell infiltration into the cornea was found in CXCL9 deficient mice following HSV-1 infection consistent with the absence of CXCL9 expression and reduction in expression of other chemokines including CCL3, CCL5, CXCL1, and CXCL10. Collectively, the results suggest a non-redundant role for CXCL9 and CXCL10 in response to ocular HSV-1 infection in terms of controlling virus replication and recruitment of CD4(+) T cells into the cornea.     

The cytokine storm in COVID-19: An overview of the involvement of the chemokine/chemokine-receptor system

In 2019–2020 a new coronavirus named SARS-CoV-2 was identified as the causative agent of a several acute respiratory infection named COVID-19, which is causing a worldwide pandemic. There are still many unresolved questions regarding the pathogenesis of this disease and especially the reasons underlying the extremely different clinical course, ranging from asymptomatic forms to severe manifestations, including the Acute Respiratory Distress Syndrome (ARDS). SARS-CoV-2 showed phylogenetic similarities to both SARS-CoV and MERS-CoV viruses, and some of the clinical features are shared between COVID-19 and previously identified beta-coronavirus infections. Available evidence indicate that the so called “cytokine storm” an uncontrolled over-production of soluble markers of inflammation which, in turn, sustain an aberrant systemic inflammatory response, is a major responsible for the occurrence of ARDS. Chemokines are low molecular weight proteins with powerful chemoattractant activity which play a role in the immune cell recruitment during inflammation. This review will be aimed at providing an overview of the current knowledge on the involvement of the chemokine/chemokine-receptor system in the cytokine storm related to SARS-CoV-2 infection. Basic and clinical evidences obtained from previous SARS and MERS epidemics and available data from COVID-19 will be taken into account.     

Higher circulating levels of chemokines CXCL10, CCL20 and CCL22 in patients with ischemic heart disease

Recruitment of leukocytes is one of the earliest events in the pathogenesis of ischemic heart disease (IHD) and chemokines play an important role in the migration of these cells into the inflammation sites. The aim of this study was to evaluate the CXCL10, CCL20 and CCL22 levels and the single nucleotide polymorphisms (SNPs) rs4508917, rs6749704 and rs4359426 in chemokine genes in patients with IHD to clarify any association. A total of 300 patients with IHD as having acute myocardial infarction (AMI; n = 100), stable angina (SA; n = 100) or unstable angina (UA; n = 100) and 100 healthy subjects as a control group were enrolled to study. Serum samples from all participants were tested for the CXCL10, CCL20 and CCL22 levels by using ELISA. The SNPs were determined by polymerase chain reaction–restriction length polymorphism (PCR–RFLP) method. The mean serum concentrations of CXCL10, CCL20 and CCL22 in AMI patients (395.97 ± 21.20 Pg/mL, 108.38 ± 10.31 Pg/mL and 1852.58 ± 205.77 Pg/mL), SA patients (405.48 ± 27.36 Pg/mL, 90.20 ± 7.69 Pg/mL and 2322.04 ± 231.23 Pg/mL) and UA patients (396.69 ± 22.79 Pg/mL, 141.87 ± 18.10 Pg/mL and 2754.89 ± 211.70 Pg/mL) were significantly higher than in the healthy group (179.38 ± 8.85 Pg/mL, 51.92 ± 4.62 Pg/mL and 451.82 ± 23.76 Pg/mL, respectively; P < 0.001). Similarly, the serum levels of CXCL10, CCL20 and CCL22 in total IHD patients (399.38 ± 13.77 Pg/mL, 113.49 ± 7.48 Pg/mL and 2309.84 ± 126.39 Pg/mL, respectively) were also significantly higher as compared with healthy subjects (P < 0.001). The serum levels of CCL20 and CCL22 in UA patients were significantly higher than those in SA and AMI patients, respectively (P < 0.01 and P < 0.003, respectively). The serum levels of CXCL10 and CCL20 in diabetic patients were significantly higher in comparison to non-diabetic patients (P < 0.05 and P < 0.02, respectively). The serum levels of CCL22 in dyslipidemic- and obese patients were also significantly higher in comparison with non-dyslipidemic- and non-obese patients, correspondingly (P < 0.05 and P < 0.01, respectively). There were no significant differences between men and women or between patients who treated with statin, aspirin, β-blockers or angiotensin converting enzyme (ACE) inhibitors and patients without mentioned treatment regarding the levels of chemokines. The frequency of the GG genotype at SNP rs4508917 in CXCL10 gene was higher, whereas the frequency of the AA genotype at SNP rs4359426 in CCL22 gene was lower in total patients with IHD as compared with healthy subjects (P < 0.04 and P < 0.002, respectively). These results showed that the higher levels of CXCL10, CCL20 and CCL22 were associated with IHD. The serum levels of chemokines may influence by the certain traditional risk factors of IHD and some studied SNPs, but did not influence by treatment and gender of patients.     

Co-expression of the proto-oncogene fos (c-fos) and an embryonic interferon (ovine trophoblastin) by sheep conceptuses during implantation.

Expression of the c-fos proto-oncogene by ovine conceptuses was analyzed by Northern and slot blots and indirect immunohistofluorescence in relation to the expression of the embryonic interferon-alpha (oTP) during implantation. c-fos was expressed initially in the trophoblast, and then in the allantois, when this tissue began to develop (day 17). In the embryonic tissues, the c-fos proto-oncogene was weakly expressed up to day 22 and increased thereafter. In the trophoblast, the expression of c-fos proto-oncogene was transient, occurring when the oTP gene was transcribed at a maximal level at the beginning of implantation (days 14-15), and decreased thereafter, following the pattern of oTP gene expression. This decline is due essentially to the arrest of c-fos and oTP gene expression by the trophoblastic cells which established cellular contacts with the uterine epithelium during the implantation process.     

Normalizing the bone marrow microenvironment with p38 inhibitor reduces multiple myeloma cell proliferation and adhesion and suppresses osteoclast formation

The multiple myeloma (MM) bone marrow (BM) microenvironment plays a critical role in supporting tumor growth and survival as well as in promoting formation of osteolytic lesions. Recent results suggest that the p38 mitogen-activated protein kinase (MAPK) is an important factor in maintaining this activated environment. In this report, we demonstrate that the p38alpha MAPK inhibitor, SCIO-469, suppresses secretion of the tumor-supportive factors IL-6 and VEGF from BM stromal cells (BMSCs) as well as cocultures of BMSCs with MM cells, resulting in reduction in MM cell proliferation. Additionally, we show that SCIO-469 prevents TNFalpha-induced adhesion of MM cells to BMSCs through an ICAM-1- and VCAM-1-independent mechanism. Microarray analysis revealed a novel set of TNFalpha-induced chemokines in BMSCs that is strongly inhibited by SCIO-469. Furthermore, reintroduction of chemokines CXCL10 and CCL8 to BMSCs overcomes the inhibitory effect of SCIO-469 on TNFalpha-induced MM adhesion. Lastly, we show that SCIO-469 inhibits secretion and expression of the osteoclast-activating factors IL-11, RANKL, and MIP-1alpha as well as prevents human osteoclast formation in vitro. Collectively, these results suggest that SCIO-469 treatment can suppress factors in the bone marrow microenvironment to inhibit MM cell proliferation and adhesion and also to alleviate osteolytic activation in MM.     

CXC chemokine ligand 12/Stromal cell-derived factor-1 regulates cell adhesion in human colon cancer cells by induction of intercellular adhesion molecule-1

Background

Gene therapy and viral therapy are used for cancer therapy for many years, but the results are less than satisfactory. Our aim was to construct a new recombinant adenovirus which is more efficient to kill hepatocarcinoma cells but more safe to normal cells.

Methods

By using the Cancer Targeting Gene-Viro-Therapy strategy, Apoptin, a promising cancer therapeutic gene was inserted into the double-regulated oncolytic adenovirus AD55 in which E1A gene was driven by alpha fetoprotein promoter along with a 55 kDa deletion in E1B gene to form AD55-Apoptin. The anti-tumor effects and safety were examined by western blotting, virus yield assay, real time polymerase chain reaction, 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, Hoechst33342 staining, Fluorescence-activated cell sorting, xenograft tumor model, Immunohistochemical assay, liver function analysis and Terminal deoxynucleotidyl transferase mediated dUTP Nick End Labeling assay.

Results

The recombinant virus AD55-Apoptin has more significant antitumor effect for hepatocelluar carcinoma cell lines (in vitro) than that of AD55 and even ONYX-015 but no or little impair on normal cell lines. Furthermore, it also shows an obvious in vivo antitumor effect on the Huh-7 liver carcinoma xenograft in nude mice with bigger beginning tumor volume till about 425 mm3 but has no any damage on the function of liver. The induction of apoptosis is involved in AD55-Apoptin induced antitumor effects.

Conclusion

The AD55-Apoptin can be a potential anti-hepatoma agent with remarkable antitumor efficacy as well as higher safety in cancer targeting gene-viro-therapy system.     

Expression of VEGF-receptor system in conceptus during peri-implantation period and endometrial and luteal expression of soluble VEGFR-1 in the pig

In view of the importance of vascular events observed during gestation, it was hypothesized that the VEGF-receptor system plays a critical role during early pregnancy and maternal recognition of pregnancy in pigs. This hypothesis was tested by examining the expression of the VEGF-receptor system in the porcine conceptus. Additionally, the endometrium, corpus luteum (CL) and embryos were studied for the expression of soluble VEGF receptor 1 (sVEGFR-1), the strong endogenous antagonist of VEGF. The expression patterns show that VEGF164 mRNA levels increase gradually in line with conceptus development, whereas VEGF120 and VEGFR-2 remain unchanged during the peri-implantation period. Interestingly, elevated VEGFR-1 expression was observed in conceptuses on days 15-16 of gestation (P < 0.05). Comparison of the endometrial sVEGFR-1 mRNA expression revealed up-regulation on days 12 and 15-16 of pregnancy (P < 0.01 and P < 0.05, respectively). Furthermore, increased sVEGFR-1 levels were observed on day 12 of the estrous cycle in the CL (P < 0.05). Concluding, it seems that conceptus-derived VEGF164 plays crucial role in peri-implantation vascular events in pigs. These results support a potential role of VEGFR-1 in the proper growth and development of porcine conceptus during pregnancy. Moreover, expression patterns of sVEGFR-1 in the endometrium of pregnant pigs suggest that it may participate in vascular remodeling important for successful implantation. Finally, luteal sVEGFR-1 may be involved in the maintenance of CL function whenever pregnancy occurs in pigs.     

An ultrastructural study of the role of an extracellular matrix during normal cleavage in a marsupial,the brushtail possum

In marsupials, the mechanisms of lineage allocation into pluriblast and trophoblast are related to conceptus polarity and polarized discharge of extracellular matrix (ECM). The brushtail possum, Trichosurus vulpecula, a major pest species in New Zealand, is being intensively studied to develop an immunocontraceptive control method. Of 23 specimens examined, 11 were examined by electron microscopy to study the presence and role of the ECM in lineage allocation in the possum. A number of polarized features in the zygote identified the future embryonic and abembryonic poles. Pronuclei, in a broad band of mitochondrion-rich cortical cytoplasm, lay in the embryonic hemisphere, and numerous electron-lucent vesicles characterized the abembryonic cytoplasm. These vesicles seemed to contribute to the ECM. During cleavage, cells lay near the zona in the embryonic hemisphere, and ECM accumulated chiefly in the abembryonic hemisphere. Cell-zona adhesion facilitated by microvillous and club processes occurred at the early 4-cell stage, and cell-cell adhesion commenced at the late 4-cell stage. The first two cleavages were meridional, equal, and accompanied by elimination into the cleavage cavity of much of the electron-lucent vesicular material in the form of several membrane-bound yolk masses. The third cleavage was unequal, with both meridional and latitudinal planes. The first differences between trophoblast and pluriblast lineages appeared at the 8-cell stage. Later cleavage planes were latitudinal or oblique. Conceptus polarity, polarized discharge of ECM, and localized cell-zona adhesion were related to the first lineage allocation in the possum. Mol. Reprod. Dev. 50:420–433, 1998. © 1998 Wiley-Liss, Inc.     

Regulation of the adhesion ofPseudomonas fluorescens cells to glass by extracellular volatile compounds

The effect of the gaseous metabolites of onePseudomonas fluorescens culture on the attachment of cells of anotherP. fluorescens culture to glass was studied. Gaseous metabolites increased the number of unattached cells by 10–30% and the mean residence time of cells attached to glass by 100%. These effects were presumably due to the yet unidentified compound, which we called volatile antiadhesin. This compound could be adsorbed by activated charcoal and HAYESEP-Q adsorbent.     

Integrin alpha4beta1 involvement in stromal cell-derived factor-1alpha-promoted myeloma cell transendothelial migration and adhesion: role of cAMP and the actin cytoskeleton in adhesion

The chemokine stromal cell-derived factor-1alpha (SDF-1alpha) is expressed by bone marrow (BM) stromal cells and plays key roles in cell homing to and retention into the bone marrow. In multiple myeloma, blood-borne malignant plasma cells home to the BM and accumulate in contact with stromal cells, implicating myeloma cell migration across endothelium. Myeloma cells express the SDF-1alpha receptor CXCR4, as well as the integrin alpha4beta1, which mediates their attachment to BM stroma. We show here that SDF-1alpha promotes transendothelial migration of purified BM myeloma cells and myeloma-derived NCI-H929 cells, involving a transient upregulation of alpha4beta1-dependent cell adhesion to the endothelium. Characterization of intracellular signaling pathways involved in the modulation by SDF-1alpha of alpha4beta1-mediated myeloma cell adhesion revealed that intracellular cAMP amounts associated with the activation of protein kinase A play key roles in this modulation. Furthermore, a functional link between cAMP actions on the dynamics of actin cytoskeleton, RhoA activation, and alpha4beta1-dependent cell adhesion in response to SDF-1alpha has been found. The regulation of alpha4beta1-mediated myeloma cell adhesion by SDF-1alpha could play key roles during myeloma cell homing into and trafficking inside the BM, and characterization of the molecular events involved in SDF-1alpha-activated modulation of this adhesion will contribute to a better understanding of mechanisms participating in cell migration.     

Regulation of cell adhesion signaling by synthetic glycopolymer matrix in primary cultured hepatocyte

Control of cell-matrix interactions is a central principle for the design of biomaterial in tissue engineering. In this study, we evaluated a synthetic glycopolymer, which is recognized by the asialoglycoprotein receptor (ASGPR) expressed on the surface of hepatocytes, as an artificial matrix to regulate integrin-mediated signaling. The phosphorylation of focal adhesion kinase was restricted in hepatocytes cultured on the glycopolymer compared with fibronectin. In addition, there was no reorganization of cytoskeleton-related proteins such as actin filaments, microtubules, and vinculin in hepatocytes cultured on the glycopolymer. DNA synthesis and cyclin D1 expression were suppressed in hepatocytes grown on the glycopolymer as compared with those grown on fibronectin and collagen. The data suggest that the glycopolymer will be a good artificial matrix to regulate integrin-mediated signaling and cell growth through the unique ASGPR-carbohydrate interaction.