Induction of copper/zinc-superoxide dismutase by CCL5/CCR5 activation causes tumour necrosis factor-alpha and reactive oxygen species production in macrophages

CCR5 and inflammatory storm

Chemokines and their corresponding receptors play crucial roles in orchestrating inflammatory and immune responses, particularly in the context of pathological conditions disrupting the internal environment. Among these receptors, CCR5 has garnered considerable attention due to its significant involvement in the inflammatory cascade, serving as a pivotal mediator of neuroinflammation and other inflammatory pathways associated with various diseases. However, a notable gap persists in comprehending the intricate mechanisms governing the interplay between CCR5 and its ligands across diverse and intricate inflammatory pathologies. Further exploration is warranted, especially concerning the inflammatory cascade instigated by immune cell infiltration and the precise binding sites within signaling pathways. This study aims to illuminate the regulatory axes modulating signaling pathways in inflammatory cells by providing a comprehensive overview of the pathogenic processes associated with CCR5 and its ligands across various disorders. The primary focus lies on investigating the pathomechanisms associated with CCR5 in disorders related to neuroinflammation, alongside the potential impact of aging on these processes and therapeutic interventions. The discourse culminates in addressing current challenges and envisaging potential future applications, advocating for innovative research endeavors to advance our comprehension of this realm.

The effect of hyperglycemia on the activation of peritoneal macrophages of albino rats

Hyperglycemia is one of the main damaging factors of diabetes mellitus (DM). The severity of this disease is most clearly manifested under conditions of the inflammatory process. In this work, we have studied the activation features of rat peritoneal macrophages (MPs) under conditions of high glucose concentration in vitro. Comparison of the independent and combined effects of streptozotocin-induced DM and hyperglycemia on proliferation and accumulation of nitrites in the MPs culture medium revealed similarity of their effects. Elevated glucose levels and, to a lesser extent, DM decreased basal proliferation and NO production by MPs in vitro. The use of the protein kinase C (PKC) activator, phorbol ester (PMA), abolished the proinflammatory effect of thrombin on PMs. This suggests the involvement of PKC in the effects of the protease. At the same time, the effect of thrombin on the level of nitrites in the culture medium demonstrates a pronounced dose-dependence, which was not recognized during evaluation of proliferation. Proinflammatory activation of MPs is potentiated by hyperglycemia, one of the main pathological factors of diabetes. Despite the fact that high concentrations of glucose have a significant effect on proliferation and NO production, no statistically significant differences were found between the responses of MPs obtained from healthy animals and from animals with streptozotocin-induced DM. This ratio was observed for all parameters studied in the work, during analysis of cell proliferation and measurement of nitrites in the culture medium. Thus, the results obtained indicate the leading role of elevated glucose levels in the regulation of MPs activation, which is comparable to the effect of DM and even "masks" it.

HSV-1 infection-induced herpetic neuralgia involves a CCL5/CCR5-mediated inflammation mechanism

Herpetic-related neuralgia (HN) caused by varicella-zoster virus (VZV) infection is one of the most typical and common neuropathic pain in the clinic. However, the potential mechanisms and therapeutic approaches for the prevention and treatment of HN are still unclear. This study aims to provide a comprehensive understanding of the molecular mechanisms and potential therapeutic targets of HN. We used an HSV-1 infection-induced HN mouse model and screened the differentially expressed genes (DEGs) in the DRG and spinal cord using an RNAseq technique. Moreover, bioinformatics methods were used to figure out the signaling pathways and expression regulation patterns of the DEGs enriched. In addition, quantitative real-time RT-PCR and western blot were carried out to further confirm the expression of DEGs. HSV-1 inoculation in mice resulted in mechanical allodynia, thermal hyperalgesia, and cold allodynia, following the infection of HSV-1 in both DRG and spinal cord. Besides, HSV-1 inoculation induced an up-regulation of ATF3, CGRP, and GAL in DRG and activation of astrocytes and microglia in the spinal cord. Moreover, 639 genes were upregulated, 249 genes were downregulated in DRG, whereas 534 genes were upregulated and 12 genes were downregulated in the spinal cord of mice 7 days after HSV-1 inoculation. GO and KEGG enrichment analysis suggested that immune responses and cytokine-cytokine receptor interaction are involved in DRG and spinal cord neurons in mice after HSV-1 infection. In addition, CCL5 and its receptor CCR5 were significantly upregulated in DRG and spinal cord upon HSV-1 infection in mice. And blockade of CCR5 exhibited a significant analgesic effect and suppressed the upregulation of inflammatory cytokines in DRG and spinal cord induced by HSV-1 infection in mice. HSV-1 infection-induced allodynia and hyperalgesia in mice through dysregulation of immune response and cytokine-cytokine receptor interaction mechanism. Blockade of CCR5 alleviated allodynia and hyperalgesia probably through the suppression of inflammatory cytokines. Therefore, CCR5 could be a therapeutic target for the alleviation of HSV-1 infection-induced HN.

The Cuproptosis-Related Long Noncoding RNA Signature Predicts Prognosis and Immune Cell Infiltration in Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC), ranking as one of the most common malignant tumors, is one of the leading causes of cancer death, with a poor prognosis. Cuproptosis, a novel programmed cell death modality that has just been confirmed recently, may play an important role in HCC prognosis. Long noncoding RNA (LncRNA) is a key participant in tumorigenesis and immune responses. It may be of great significance to predict HCC based on cuproptosis genes and their related LncRNA.

Methods

The sample data on HCC patients were obtained from The Cancer Genome Atlas (TCGA) database. Combined with cuproptosis-related genes collected from the literature search, expression analysis was carried out to find cuproptosis genes and their related LncRNAs significantly expressed in HCC. The prognostic model was constructed by least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox regression. The feasibility of these signature LncRNAs used for the evaluation of the overall survival rate in HCC patients as independent factors was investigated. The expression profile of cuproptosis, immune cell infiltration, and the status of somatic mutation were analyzed and compared.

Results

A prognostic model of HCC consisting of seven cuproptosis gene-related LncRNA signatures was constructed. Multiple verification methods have showed that this model can accurately predict the prognosis of HCC patients. It was showed that the classified high-risk group under the risk score of this model had worse survival status, more significant expression of the immune function, and higher mutation frequency. During the analysis, the cuproptosis gene CDKN2A was found to be most closely related to LncRNA DDX11-AS1 in the expression profile of HCC patients.

Conclusion

The cuproptosis-related signature LncRNA in HCC was identified, on the basis of which a model was constructed, and it was verified that it can be used to predict the prognosis of HCC patients. The potential role of these cuproptosis-related signature LncRNAs as new targets for disease therapy in antagonizing HCC development was discussed.

CCL5 via GPX1 activation protects hippocampal memory function after mild traumatic brain injury

Traumatic brain injury (TBI) is a prevalent head injury worldwide which increases the risk of neurodegenerative diseases. Increased reactive oxygen species (ROS) and inflammatory chemokines after TBI induces secondary effects which damage neurons. Targeting NADPH oxidase or increasing redox systems are ways to reduce ROS and damage. Earlier studies show that C–C motif chemokine ligand 5 (CCL5) has neurotrophic functions such as promoting neurite outgrowth as well as reducing apoptosis. Although CCL5 levels in blood are associated with severity in TBI patients, the function of CCL5 after brain injury is unclear. In the current study, we induced mild brain injury in C57BL/6 (wildtype, WT) mice and CCL5 knockout (CCL5-KO) mice using a weight-drop model. Cognitive and memory functions in mice were analyzed by Novel-object-recognition and Barnes Maze tests. The memory performance of both WT and KO mice were impaired after mild injury. Cognition and memory function in WT mice quickly recovered after 7 days but recovery took more than 14 days in CCL5-KO mice. FJC, NeuN and Hypoxyprobe staining revealed large numbers of neurons damaged by oxidative stress in CCL5-KO mice after mTBI. NADPH oxidase activity show increased ROS generation together with reduced glutathione peroxidase-1 (GPX1) and glutathione (GSH) activity in CCL5-KO mice; this was opposite to that seen in WT mice. CCL5 increased GPX1 expression and reduced intracellular ROS levels which subsequently increased cell survival both in primary neuron cultures and in an overexpression model using SHSY5Y cell. Memory impairment in CCL5-KO mice induced by TBI could be rescued by i.p. injection of the GSH precursor – N-acetylcysteine (NAC) or intranasal delivery of recombinant CCL5 into mice after injury. We conclude that CCL5 is an important molecule for GPX1 antioxidant activation during post-injury day 1–3, and protects hippocampal neurons from ROS as well as improves memory function after trauma.

Targeting inhibition of CCR5 on improving obesity-associated insulin resistance and impairment of pancreatic insulin secretion in high fat-fed rodent models

Obesity is closely linked with type 2 diabetes and the effective therapies on obesity-associated diabetes are under development. The aim of this study was undertaken to investigate whether the inhibition of the augmented CCR5-mediated signaling could be a common target for treatment of obesity-associated insulin resistance and impairment of pancreatic insulin secretion in high-fat diet (HFD) fed rats and CCR5 knockout mice and also in isolated islets and RIN-m5F cells. Conducted with SD rats, HFD-induced body weight gain was significantly decreased in those combined with Maraviroc treatment, but food intake remained similar compared to control. Maraviroc also significantly improved the impaired oral glucose tolerance test (OGTT). As compared with wild-type mice, CCR5 deletion significantly attenuated the HFD-induced increases in glucose area under curve of OGTT and the value of HOMA-IR as well as plasma lipid profile. It also reversed the HFD-suppressed gene expressions of GLUT4 and IRS-1 in adipose tissue. On the other hand, the HFD-associated islet macrophage and T-cell infiltration were significantly decreased in CCR5 KO mice. H2O2 significantly suppressed glucose-stimulated insulin secretion (GSIS) is isolated islets, which were significantly reversed in those cotreated with CCR5 mAb. H2O2 failed to change GSIS in those of CCR5 KO mice. The palmitate-induced reactive oxygen species production was significantly decreased in those cotreated with CCR5 antagonist in RIN-m5F cells. Collectively, it is suggested that targeting inhibition of the CCR5 mediated inflammatory pathway could not only improve obesity-associated insulin resistance but also directly alleviate pancreatic β-cell dysfunction.

Dietary inulin decreases circulating ceramides by suppressing neutral sphingomyelinase expression and activity in mice

Elevated circulating levels of ceramides (Cers) are associated with increased risk of cardiometabolic diseases, and Cers may play a causative role in metabolic dysfunction that precedes cardiac events, such as mortality as a result of coronary artery disease. Although the mechanisms involved are likely complex, these associations suggest that lowering circulating Cer levels could be protective against cardiovascular diseases. Conversely, dietary fibers, such as inulin, have been reported to promote cardiovascular and metabolic health. However, the mechanisms involved in these protective processes also are not well understood. We studied the effects of inulin on lipid metabolism with a model of atherosclerosis in LDL receptor-deficient mice using lipidomics and transcriptomics. Plasma and tissues were collected at 10 days and/or 12 weeks after feeding mice an atherogenic diet supplemented with inulin or cellulose (control). Compared with controls, inulin-fed mice displayed a decreased C16:0/C24:0 plasma Cer ratio and lower levels of circulating Cers associated with VLDL and LDL. Liver transcriptomic analysis revealed that Smpd3, a gene that encodes neutral SMase (NSMase), was downregulated by 2-fold in inulin-fed mice. Hepatic NSMase activity was 3-fold lower in inulin-fed mice than in controls. Furthermore, liver redox status and compositions of phosphatidylserine and FFA species, the major factors that determine NSMase activity, were also modified by inulin. Taken together, these results showed that, in mice, inulin can decrease plasma Cer levels through reductions in NSMase expression and activity, suggesting a mechanism by which fiber could reduce cardiometabolic disease risk.

Redox-signals and macrophage biology

Macrophages are known for their versatile role in biology. They sense and clear structures that contain exogenous or endogenous pathogen-associated molecular patterns. This process is tightly linked to the production of a mixture of potentially harmful oxidants and cytokines. Their inherent destructive behavior is directed against foreign material or structures of 'altered self', which explains the role of macrophages during innate immune reactions and inflammation. However, there is also another side of macrophages when they turn into a tissue regenerative, pro-resolving, and healing phenotype. Phenotype changes of macrophages are termed macrophage polarization, representing a continuum between classical and alternative activation. Macrophages as the dominating producers of superoxide/hydrogen peroxide and nitric oxide are not only prone to oxidative modifications but also to more subtle signaling properties of redox-active molecules conveying redox regulation. We review basic concepts of the enzymatic nitric oxide and superoxide production within macrophages, refer to their unique chemical reactions and outline biological consequences not only for macrophage biology but also for their communication with cells in the microenvironment. These considerations link hypoxia to the NO system, addressing feedforward as well as feedback circuits. Moreover, we summarize the role of redox-signaling affecting epigenetics and reflect the central role of mitochondrial-derived oxygen species in inflammation. To better understand the diverse functions of macrophages during initiation as well as resolution of inflammation and to decode their versatile roles during innate and adaptive immunity with the entire spectrum of cell protective towards cell destructive activities we need to appreciate the signaling properties of redox-active species. Herein we discuss macrophage responses in terms of nitric oxide and superoxide formation with the modulating impact of hypoxia.

Pharmacological evaluation of hybrid thiazolidin-4-one-1,3,5-triazines for NF-κB, biofilm and CFTR activity

A series of hybrid thiazolidin-4-one-1,3,5-triazines was evaluated for NF-κB, biofilm and CFTR activity.

Cancer-associated fibroblasts expressing CXCL14 rely upon NOS1-derived nitric oxide signaling for their tumor-supporting properties

Cancer-associated fibroblasts (CAF) stimulate tumor growth and metastasis. Signals supporting CAF function are thus emerging as candidate therapeutic targets in the tumor microenvironment. The chemokine CXCL14 is a potent inducer of CAF protumorigenic functions. This study is aimed at learning how the protumoral functions of CXCL14-expressing CAF are maintained. We found that the nitric oxide synthase NOS1 is upregulated in CXCL14-expressing CAF and in fibroblasts stimulated with CXCL14. Induction of Nos1 was associated with oxidative stress and occurred together with activation of NRF2 and HIF1α signaling in CXCL14-expressing CAF. Genetic or pharmacologic inhibition of NOS1 reduced the growth of CXCL14-expressing fibroblasts along with their ability to promote tumor formation following coinjection with prostate or breast cancer cells. Tumor analysis revealed reduced macrophage infiltration, with NOS1 downregulation in CXCL14-expressing CAF and lymphangiogenesis as a novel component of CXCL14-promoted tumor growth. Collectively, our findings defined key components of a signaling network that maintains the protumoral functions of CXCL14-stimulated CAF, and they identified NOS1 as intervention target for CAF-directed cancer therapy.

HIV-1 Nef induces CCL5 production in astrocytes through p38-MAPK and PI3K/Akt pathway and utilizes NF-kB, CEBP and AP-1 transcription factors

The prevalence of HIV-associated neurocognitive disorders (HAND) remains high in patients infected with HIV-1. The production of pro-inflammatory cytokines by astrocytes/microglia exposed to viral proteins is thought to be one of the mechanisms leading to HIV-1- mediated neurotoxicity. In the present study we examined the effects of Nef on CCL5 induction in astrocytes. The results demonstrate that CCL5 is significantly induced in Nef-transfected SVGA astrocytes. To determine the mechanisms responsible for the increased CCL5 caused by Nef, we employed siRNA and chemical antagonists. Antagonists of NF-κB, PI3K, and p38 significantly reduced the expression levels of CCL5 induced by Nef transfection. Furthermore, specific siRNAs demonstrated that the Akt, p38MAPK, NF-κB, CEBP, and AP-1 pathways play a role in Nef-mediated CCL5 expression. The results demonstrated that the PI3K/Akt and p38 MAPK pathways, along with the transcription factors NF-κB, CEBP, and AP-1, are involved in Nef-induced CCL5 production in astrocytes.

HIV-1 Tat-mediated induction of CCL5 in astrocytes involves NF-κB, AP-1, C/EBPα and C/EBPγ transcription factors and JAK, PI3K/Akt and p38 MAPK signaling pathways

The incidence of HIV-associated neurological disorders (HAND) has increased during recent years even though the highly active antiretroviral therapy (HAART) has significantly curtailed the virus replication and increased the life expectancy among HIV-1 infected individuals. These neurological deficits have been attributed to HIV proteins including HIV-1 Tat. HIV-1 Tat is known to up-regulate CCL5 expression in mouse astrocytes, but the mechanism of up-regulation is not known. The present study was undertaken with the objective of determining the mechanism(s) underlying HIV-1 Tat-mediated expression of CCL5 in astrocytes. SVGA astrocytes were transiently transfected with a plasmid encoding Tat, and expression of CCL5 was studied at the mRNA and protein levels using real time RT-PCR and multiplex cytokine bead array, respectively. HIV-1 Tat showed a time-dependent increase in the CCL5 expression with peak mRNA and protein levels, observed at 1 h and 48 h post-transfection, respectively. In order to explore the mechanism(s), pharmacological inhibitors and siRNA against different pathway(s) were used. Pre-treatment with SC514 (NF-κB inhibitor), LY294002 (PI3K inhibitor), AG490 (JAK2 inhibitor) and Janex-1 (JAK3 inhibitor) showed partial reduction of the Tat-mediated induction of CCL5 suggesting involvement of JAK, PI3K/Akt and NF-κB in CCL5 expression. These results were further confirmed by knockdown of the respective genes using siRNA. Furthermore, p38 MAPK was found to be involved since the knockdown of p38δ but not other isoforms showed partial reduction in CCL5 induction. This was further confirmed at transcriptional level that AP-1, C/EBPα and C/EBPγ were involved in CCL5 up-regulation.

Normal ageing is associated with an increase in Th2 cells, MCP-1 (CCL1) and RANTES (CCL5), with differences in sCD40L and PDGF-AA between sexes

We have observed T helper type 2 (Th2) polarization of systemic immunity in patients with metastatic malignant melanoma. We hypothesized that similar changes in systemic immunity occur with ageing and may be permissive for the development of melanoma. We analysed the peripheral blood of 389 healthy blood donors. All subjects were profiled for peripheral blood T cell and B cell subsets, and 58 of these subjects were profiled for antigen-specific cytotoxic T cell subsets [cytomegalovirus (CMV), influenza and melanoma antigen recognized by T cells 1 (MART-1)]. Ninety-five separate healthy subjects underwent profiling of 42 plasma cytokines. Ageing was associated positively with CD4(+) CD294(+) Th2 cells, and associated negatively with CD3(+) T cells, cytotoxic T cells and T helper cells. Ageing was also associated negatively with CMV-, influenza- and MART-1-specific naive and CD8(+) T cells. There were significant increases in plasma monocyte chemotactic protein 1 (MCP-1) (CCL1) and regulated upon activation normal T cell expressed and secreted (RANTES) (CCL5) with age. We observed differences in cytokine profiles between males and females; specifically, women had higher levels of sCD40L and PDGF-AA. In summary, we demonstrated in healthy blood donors that ageing was associated with an increase in cellular Th2 bias and a decline in total numbers of T cells. Additionally, there was an increase in MCP-1 and RANTES with ageing. Women had higher levels of sCD40L and PDGF-AA than men.

CCL5 induces a pro-inflammatory profile in microglia in vitro

The chemokine receptors CCR1, CCR2, CCR3, CCR5, and CXCR2 have been found to be expressed on microglia in many neurodegenerative diseases, such as multiple sclerosis and Alzheimer's disease. There is emerging evidence that chemokines, besides chemoattraction, might directly modulate reactive profiles of microglia. To address this hypothesis we have investigated the effects of CCL2, CCL3, CCL5, and CXCL1 on cytokine and growth factor production, NO synthesis, and phagocytosis in non-stimulated and lipopolysaccharide-stimulated primary rat microglia. The respective receptors CCR1, CCR5, and CXCR2 were shown to be functionally expressed on microglia. All tested chemokines stimulated chemotaxis whereas only CCL5 increased NO secretion and attenuated IL-10 as well as IGF-1 production in activated microglia. Based on these findings we propose that besides its chemoattractant function CCL5 has a modulatory effect on activated microglia.

Mechanisms of spatial and temporal development of autoimmune vitiligo in tyrosinase-specific TCR transgenic mice

Generalized vitiligo is thought to have an autoimmune etiology and has been correlated with the presence of CD8 T cells specific for melanocyte differentiation Ag. However, limited animal models for the disease have hampered its understanding. Thus, we generated TCR transgenic mice that recognize an epitope of the melanocyte protein, tyrosinase. These animals develop vitiligo with strikingly similar characteristics to the human disease. Vitiligo develops temporally and spatially, with juvenile lesions forming bilaterally in head and facial areas, and only arising later in the body of adult animals. Vitiligo is entirely dependent on CD8 T cells, whereas CD4 T cells exert a negative regulatory effect. Importantly, CD8 T cells can be pervasively present in the skin in the steady state without inducing vitiligo in most areas. This points to developmental differences in melanocyte susceptibility and/or immunological effector mechanisms over time, or in different body locations. Disease is strongly dependent on both IFN-gamma and CXCR3, whereas dependence on CCR5 is more limited, and both CCR4 and perforin are dispensable. Genetic ablation of CXCR3 or IFN-gamma also resulted in scarce CD8 T cell infiltration into the skin. Our results identify unexpected complexity in vitiligo development and point toward possible therapeutic interventions.