CXC Chemokine Research Articles

Endothelial CXCR2 deficiency attenuates renal inflammation and glycocalyx shedding through NF-κB signaling in diabetic kidney disease

BackgroundThe incidence of diabetic kidney disease (DKD) continues to rapidly increase, with limited available treatment options. One of the hallmarks of DKD is persistent inflammation, but the underlying molecular mechanisms of early diabetic kidney injury remain poorly understood. C-X-C chemokine receptor 2 (CXCR2), plays an important role in the progression of inflammation-related vascular diseases and may bridge between glomerular endothelium and persistent inflammation in DKD.MethodsMultiple methods were employed to assess the expression levels of CXCR2 and its ligands, as well as renal inflammatory response and endothelial glycocalyx shedding in patients with DKD. The effects of CXCR2 on glycocalyx shedding, and persistent renal inflammation was examined in a type 2 diabetic mouse model with Cxcr2 knockout specifically in endothelial cells (DKD-Cxcr2eCKO mice), as well as in glomerular endothelial cells (GECs), cultured in high glucose conditions.ResultsCXCR2 was associated with early renal decline in DKD patients, and endothelial-specific knockout of CXCR2 significantly improved renal function in DKD mice, reduced inflammatory cell infiltration, and simultaneously decreased the expression of proinflammatory factors and chemokines in renal tissue. In DKD conditions, glycocalyx shedding was suppressed in endothelial Cxcr2 knockout mice compared to Cxcr2L/L mice. Modulating CXCR2 expression also affected high glucose-induced inflammation and glycocalyx shedding in GECs. Mechanistically, CXCR2 deficiency inhibited the activation of NF-κB signaling, thereby regulating inflammation, restoring the endothelial glycocalyx, and alleviating DKD.ConclusionsTaken together, under DKD conditions, activation of CXCR2 exacerbates inflammation through regulation of the NF-κB pathway, leading to endothelial glycocalyx shedding and deteriorating renal function. Endothelial CXCR2 deficiency has a protective role in inflammation and glycocalyx dysfunction, suggesting its potential as a promising therapeutic target for DKD treatment.

Abstract 3181: Immune modulatory activity of radio-sensitizing gold nanoparticle

Abstract Radiation therapy (RT) is frequently used in the neoadjuvant setting in borderline resectable and some resectable pancreatic ductal adenocarcinoma (PDAC) and in the definitive setting in locally advanced PDACs which is third leading cause of cancer associated death. Higher doses of RT improve overall treatment outcomes but increasing the dose significantly above 50Gy in standard 2Gy fractions risks profound gastrointestinal (GI) toxicity. Additionally, genotoxic stress such as RT, can induce CXCL12 secretion by cancer associated fibroblast (CAFs) and overexpression of CXC motif chemokine receptor 4 (CXCR4) in cancer cells. CXCL12-CXCR4 downstream signaling results in immune suppression and consequent enhanced tumor growth and metastasis and poor prognosis in PDAC. To overcome these clinical challenges, we have developed multimodal gold nanoparticle constructs (GNPs) by functionalizing the CXCR4 antagonists to (i) bind to CXCR4 and mediate GNP internalization, (ii) abolish the feedback immune inhibitory signals mediated by CXCR4 overexpression, and (iii) enhance therapeutic benefit of radiation. To achieve these multimodal activities, we have covalently attached the CXCR4 antagonist, AMD070, to thiol-terminated polyethylene glycol (PEG) to synthesize AMD-PEG which was then conjugated with GNPs to produce AMD-PEG-GNP. In our experiment AMD-PEG-GNP has successfully inhibited CXCL12-CXCR4 downstream signalling such as reduction of ERK phosphorylation in PDAC cells. To analyze the radiosensitization role of GNP nanoconjugates, PDAC cells were incubated with AMD-PEG, PEG-GNP and AMD-PEG-GNPs for 4 hours and then treated with increasing doses of radiated, from 1-4Gy. AMD-PEG-GNP demonstrated a systematic enhancement on reactive oxygen species (ROS) production and downregulation of a colony formation. Collectively, the results from in vitro study with PDAC cells confirm that the nanoconjugate with AMD070 enhances radio-cytotoxicity and impair CXCL12-CXCR4 downstream signaling. Hence AMD-PEG-GNP has strong merit to enhance radiation dose locally and simultaneously restrict RT induced immunosuppression in PDAC. Citation Format: Tanmay Kulkarni, Shamit Dutta, Hazel Parent, Karington Perry, Yuri Mackeyev, Santanu Bhattacharya. Immune modulatory activity of radio-sensitizing gold nanoparticle [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3181.

Abstract 2760: Novel GPCR recombinant monoclonal antibodies for cancer biology research

Abstract Recombinant technology is becoming the preferred production mechanism for creation of antibody reagents used in academic and clinical cancer biology research. Recombinant antibodies (rAbs) are superior to standard polyclonal and hybridoma-generated monoclonal reagents as they offer reproducible performance and consistent, scalable supply. A major focus of antibody manufacturers is to leverage rAb production strategies to generate antibodies against challenging targets for which there are few, if any, reliable antibodies. G-protein coupled receptors (GPCRs) are encoded by more than 820 human genes and represent the largest membrane protein superfamily in the genome. These seven-pass transmembrane domain receptors are involved in a multitude of physiological and pathophysiological processes related to various chronic diseases, including an array of malignancies. Perhaps 30-40% of all therapeutics are directed against GPCR activity, and ~350 of the non-olfactory GPCRs are thought to be potential candidates for drug development. However, for a slew of technical reasons, the development and validation of high-quality antibodies against GPCRs has proven difficult. In an effort to facilitate further research into GPCRs, GeneTex is combining its recombinant antibody production platform with enhanced validation techniques to make specific monoclonal antibodies against GPCRs with direct relevance to cancer and other diseases. GeneTex’s rAb production protocol employs a multi-parameter fluorescence-activated single cell sorting (FACS)-based methodology to identify and select antigen-specific IgG+ memory B cells from an immunized rabbit (Starkie et al., 2016). The heavy and light chain variable region genes from single cells are amplified, cloned, and co-expressed in mammalian cells to generate a monoclonal IgG. Application-specific testing is performed in conjunction with knockout/knockdown (KO/KD), differential expression comparison in cells and tissues, cell fraction enrichment (i.e., membrane extracts versus whole cell extracts), and other methodologies. Antibodies directed against extracellular GPCR domains are validated for specificity using GPCR arrays (CDI Labs, Baltimore, MD). This workflow has resulted in the production of specific antibodies for a number of GPCRs studied by cancer biologists. These include novel recombinant monoclonal antibodies to the dopamine D2 receptor (DRD2), retinoic acid-induced protein 3 (RAI3), CXC motif chemokine receptor 2 (CXCR2), CXCR4, and CXCR7. All of these antibodies were validated for at least two applications, while the specificity of three (i.e., RAI3, CXCR4, and CXCR7) is supported by KO/KD data. GPCR array data argues for the specificity of the other two antibodies (i.e., DRD2 and CXCR2). This same production/validation approach will be applied as GeneTex targets the remaining GPCRs. Citation Format: Alexander Ball, Yung Lin Hsieh, Chun Kai Huang, Sega Huang, Shang Ru Wu, Yue Yun Chang, Jiming Liu, Po Shin Peng, Chia Yi Lin. Novel GPCR recombinant monoclonal antibodies for cancer biology research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2760.

Abstract 212: Repression of NKX2-1 promote epithelial-mesenchymal transition and tumor neutrophil recruitment in lung cancer progression

Abstract Background: Malignant transformation is associated with tumor aggressiveness and poor patient outcome. This cellular alteration is due to either activation of oncogenes or the silencing of tumor suppressor genes. NKX2-1 was identified as a lineage-specific gene downregulated in poorly differentiated lung adenocarcinoma (LUAD). However, the molecular mechanism and functional role of infiltrated immune cells in NKX2-1-negative tumors are not clearly understood. Methods: Clinical relevance of NKX2-1 expression and disease status were evaluated by immunohistochemical analysis of LUAD tissue arrays and the overall survival analysis of TCGA databases. In vitro and in vivo experiments were applied to confirm the role and mechanisms of NKX2-1 actions in transformed cells. The secretion of chemokines was evaluated by using chemokine array. Flow cytometry and single-cell RNA sequencing analysis of mouse tumor tissue were used to demonstrate the infiltration of neutrophils in mouse models. Results: Low expression of NKX2-1 was observed in high-grade LUAD tumors. LUAD patients who express a pattern of NKX2-1high/TGF-βlow had better survival outcomes than those with NKX2-1low/TGF-βhigh. Mechanistically, TGF-β induced the downregulation of NKX2-1 which led to enhanced epithelial-mesenchymal transition (EMT), cell motility, and CXC chemokine expression. The high release of these chemoattractants promoted the recruitment of neutrophils. Meanwhile, NKX2-1-dependent suppression of CXC chemokines gene expression may be via repressive histone methylation at the promoter region of CXC chemokines in lung cancer cells. In the in vivo syngeneic LUAD models, exacerbated neutrophil infiltration was noted. Single-cell RNA sequencing and flow cytometry both revealed that neutrophils were recruited via CXCLs/CXCR2 activation in LUAD tumors with NKX2-1 knockdown. Conclusion: Our data showed that NKX2-1 represses tumor growth, metastasis, and neutrophil recruitment via the CXCLs/CXCR2-dependent mechanisms. Notably, targeting CXCR2 in NKX2-1-negative tumors may improve LUAD patient outcomes. Citation Format: Shih-Hwa Chiou, Ping-Hsing Tsai, Mong-Lien Wang. Repression of NKX2-1 promote epithelial-mesenchymal transition and tumor neutrophil recruitment in lung cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 212.

Cathelicidin boosts the antifungal activity of neutrophils and improves prognosis during Aspergillus fumigatus keratitis.

Aspergillus fumigatus (A. fumigatus) is one of the common pathogens of fungal keratitis. Fungal growth and invasion cause excessive inflammation and corneal damage, leading to severe vision loss. Neutrophils are the primary infiltrating cells critical for fungal clearance. Cathelicidin [LL-37 in humans and cathelicidin-related antimicrobial peptide (CRAMP) in mice], a natural antimicrobial peptide, can directly inhibit the growth of many pathogens and regulate immune responses. However, the role of cathelicidin and its effect on neutrophils in A. fumigatus keratitis remain unclear. By establishing A. fumigatus keratitis mouse models, we found that cathelicidin was increased in A. fumigatus keratitis. It could reduce fungal loads, lower clinical scores, and improve corneal transparency. Restriction of CRAMP on fungal proliferation was largely counteracted in CD18-/- mice, in which neutrophils cannot migrate into infected sites. When WT neutrophils were transferred into CD18-/- mice, corneal fungal loads were distinctly reduced, indicating that neutrophils are vital for CRAMP-mediated resistance. Furthermore, cathelicidin promoted neutrophils to phagocytose and degrade conidia both in vitro and in vivo. CXC chemokine receptor 2 (CXCR2) was reported to be a functional receptor of LL-37 on neutrophils. CXCR2 antagonist SB225002 or phospholipase C (PLC) inhibitor U73122 weakened LL-37-induced phagocytosis. Meanwhile, LL-37 induced PLC γ phosphorylation, which was attenuated by SB225002. SB225002 or the autophagy inhibitors Bafilomycin-A1 and 3-Methyladenine weakened LL-37-induced degradation of conidia. Transmission electron microscopy (TEM) observed that LL-37 increased autophagosomes in Aspergillus-infected neutrophils. Consistently, LL-37 elevated autophagy-associated protein expressions (Beclin-1 and LC3-II), but this effect was weakened by SB225002. Collectively, cathelicidin reduces fungal loads and improves the prognosis of A. fumigatus keratitis. Both in vitro and in vivo, cathelicidin promotes neutrophils to phagocytose and degrade conidia. LL-37/CXCR2 activates PLC γ to amplify neutrophils' phagocytosis and induces autophagy to eliminate intracellular conidia.

CXCL1-CXCR2 axis mediates inflammatory response after sciatic nerve injury by regulating macrophage infiltration

Macrophages play a crucial role in the inflammatory response following sciatic nerve injury. Studies have demonstrated that C-X-C motif chemokine (CXCL) 1 recruit macrophages by binding to C-X-C chemokine receptor (CXCR) 2 and participates in the inflammatory response of various diseases. Based on these findings, we aimed to explore the role of the CXCL1-CXCR2 axis in the repair process after peripheral nerve injury. Initially, we simulated sciatic nerve injury and observed an increased expression of CXCL1 and CXCR2 in the nerves of the injury group. Both in vivo and in vitro experiments confirmed that the heightened CXCL1 expression occurs in Schwann cells and is secreted, while the elevated CXCR2 is expressed by recruited macrophages. In addition, in vitro experiments demonstrated that the binding of CXCL1 to CXCR2 can activate the NLRP3 inflammasome and promote the production of interleukin-1 beta (IL-1β) in macrophages. However, after mice were subjected to sciatic nerve injury, the number of macrophages and the expression of inflammatory factors in the sciatic nerve were reduced following treatment with the CXCR2 inhibitor SB225002. Simultaneously, we evaluated the sciatic nerve function index, the expression of p75 neurotrophic factor receptor (p75NTR), and myelin proteins, and all of these results were improved with the use of SB225002. Thus, our results suggest that after sciatic nerve injury, the CXCL1-CXCR2 axis mediates the inflammatory response by promoting the recruitment and activation of macrophages, which is detrimental to the repair of the injured nerves. In contrast, treatment with SB225002 promotes the repair of injured sciatic nerves.

Impact of TNF and IL-33 Cytokines on Mast Cells in Neuroinflammation.

Mast cells (MCs) are derived from hematopoietic progenitors, mature in vascularized tissues, and participate in innate and acquired immunity. Neuroinflammation is a highly debated topic in the biomedical literature; however, the impact of tumor necrosis factor (TNF) and IL-33 on MCs in the brain has not been widely addressed. MCs can be activated by IgE binding to FcεRI, as well as by different antigens. After activation, MCs mediate various immunological and inflammatory responses through TNF and IL-33. TNF has two receptors: TNFR1, a p55 molecule, and TNFR2, a p75 molecule. This cytokine is the only one of its kind to be stored in the granules of MCs and can also be generated by de novo synthesis via mRNA. In the central nervous system (CNS), TNF is produced almost exclusively by microglial cells, neurons, astrocytes, and, minimally, by endothelial cells. After its release into brain tissue, TNF rapidly induces the adhesion molecules endothelial leukocyte adhesion molecule 1 (ELAM-1), intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1) in endothelial cells. TNF causes the chemoattraction of neutrophils by inducing several molecules, including CXC chemokines (IL-8). Both MCs and microglial cells act as a primary barrier against foreign molecules in the CNS, producing pro-inflammatory cytokines such as IL-33. IL-33 belongs to the IL-1 family, is activated through the ST2L/IL1-RAcP receptor complex, and mediates both the innate and adaptive immune response. IL-33 is a nuclear transcription factor expressed in the brain, where it induces pro-inflammatory cytokines (TNF and IL-1) and chemokines (CCL2, CCL3, CCL5, and CXCL10). Therefore, MCs and microglia in the CNS are a source of pro-inflammatory cytokines, including TNF and IL-33, that mediate many brain diseases. The inhibition of TNF and IL-33 may represent a new therapeutic approach that could complement existing neuroinflammatory therapies.

Novel biomarkers of inflammation-associated immunity in cervical cancer.

Cervical cancer (CC) is a highly malignant gynecological cancer with a direct causal link to inflammation, primarily resulting from persistent high-risk human papillomavirus (HPV) infection. Given the challenges in early detection and mid to late-stage treatment, our research aims to identify inflammation-associated immune biomarkers in CC. Using a bioinformatics approach combined with experimental validation, we integrated two CC datasets (GSE39001 and GSE63514) in the Gene Expression Omnibus (GEO) to eliminate batch effects. Immune-related inflammation differentially expressed genes (DGEs) were obtained by R language identification. This analysis identified 37 inflammation-related DEGs. Subsequently, we discussed the different levels of immune infiltration between CC cases and controls. Weighted gene co-expression network analysis (WGCNA) identified seven immune infiltration-related modules in CC. We identified 15 immune DEGs associated with inflammation at the intersection of these findings. In addition, we constructed a protein interaction network using the String database and screened five hub genes using "CytoHubba": CXC chemokine ligand 8 (CXCL8), CXC chemokine ligand 10 (CXCL10), CX3C chemokine receptor 1 (CX3CR1), Fc gamma receptors 3B (FCGR3B), and SELL. The expression of these five genes in CC was determined by PCR experiments. In addition, we assessed their diagnostic value and further analyzed the association of immune cells with them. Five inflammation- and immune-related genes were identified, aiming to provide new directions for early diagnosis and mid to late-stage treatment of CC from multiple perspectives.

Biomarker analysis from the phase 2b randomized placebo-controlled trial of riociguat in early diffuse cutaneous systemic sclerosis.

To examine disease and target engagement biomarkers in the RISE-SSc trial of riociguat in early diffuse cutaneous systemic sclerosis and their potential to predict the response to treatment. Patients were randomized to riociguat (n = 60) or placebo (n = 61) for 52 weeks. Skin biopsies and plasma/serum samples were obtained at baseline and week 14. Plasma cyclic guanosine monophosphate (cGMP) was assessed using radio-immunoassay. Alpha smooth muscle actin (αSMA) and skin thickness were determined by immunohistochemistry, mRNA markers of fibrosis by qRT-PCR in skin biopsies, and serum CXC motif chemokine ligand 4 (CXCL-4) and soluble platelet endothelial cell adhesion molecule-1 (sPECAM-1) by enzyme-linked immunosorbent assay. By week 14, cGMP increased by 94 ± 78% with riociguat and 10 ± 39% with placebo (p < 0.001, riociguat vs placebo). Serum sPECAM-1 and CXCL-4 decreased with riociguat vs placebo (p = 0.004 and p = 0.008, respectively). There were no differences in skin collagen markers between the 2 groups. Higher baseline serum sPECAM-1 or the detection of αSMA-positive cells in baseline skin biopsies were associated with a larger reduction of modified Rodnan skin score from baseline at week 52 with riociguat vs placebo (interaction P-values 0.004 and 0.02, respectively). Plasma cGMP increased with riociguat, suggesting engagement with the nitric oxide-soluble guanylate cyclase-cGMP pathway. Riociguat was associated with a significant reduction in sPECAM-1 (an angiogenic biomarker) vs placebo. Elevated sPECAM-1 and the presence of αSMA-positive skin cells may help to identify patients who could benefit from riociguat in terms of skin fibrosis. Clinicaltrials.gov, NCT02283762.

Expression and clinical value of CXCR4 in high grade gastroenteropancreatic neuroendocrine neoplasms.

CXC chemokine receptor 4 (CXCR4) is associated with the progression and metastasis of numerous malignant tumors. However, its relationship with Gastroenteropancreatic Neuroendocrine Neoplasms Grade 3 (GEP-NENs G3) is unclear. The aim of this study was to characterize the expression of CXCR4 in GEP-NENS and to explore the clinical and prognostic value of CXCR4. This study retrospectively collected clinical and pathological data from patients with GEP-NENs who receiving surgery in Qilu Hospital of Shandong University from January 2013 to April 2021, and obtained the overall survival of the patients based on follow-up. Immunohistochemistry (IHC) was performed on pathological paraffin sections to observe CXCR4 staining. Groups were made according to pathological findings. Kaplan-Meier (K-M) curve was used to evaluate prognosis. SPSS 26.0 was used for statistical analysis. 100 GEP-NENs G3 patients were enrolled in this study. There was a significant difference in primary sites (P=0.002), Ki-67 index (P<0.001), and Carcinoembryonic Antigen (CEA) elevation (P=0.008) between neuroendocrine tumor (NET) G3 and neuroendocrine carcinoma (NEC). CXCR4 was highly expressed only in tumors, low or no expressed in adjacent tissues (P<0.001). The expression level of CXCR4 in NEC was significantly higher than that in NET G3 (P=0.038). The K-M curves showed that there was no significant difference in overall survival between patients with high CXCR4 expression and patients with low CXCR4 expression, either in GEP-NEN G3 or NEC (P=0.920, P=0.842. respectively). Differential expression of CXCR4 was found between tumor and adjacent tissues and between NET G3 and NEC. Our results demonstrated that CXCR4 can be served as a new IHC diagnostic indicator in the diagnosis and differential diagnosis of GEP-NENs G3. Further studies with multi-center, large sample size and longer follow-up are needed to confirm the correlation between CXCR4 expression level and prognosis.

Impaired innate and adaptive immune responses to BNT162b2 SARS-CoV-2 vaccination in systemic lupus erythematosus.

Understanding the immune responses to SARS-CoV-2 vaccination is critical to optimizing vaccination strategies for individuals with autoimmune diseases, such as systemic lupus erythematosus (SLE). Here, we comprehensively analyzed innate and adaptive immune responses in 19 patients with SLE receiving a complete 2-dose Pfizer-BioNTech mRNA vaccine (BNT162b2) regimen compared with a control cohort of 56 healthy control (HC) volunteers. Patients with SLE exhibited impaired neutralizing antibody production and antigen-specific CD4+ and CD8+ T cell responses relative to HC. Interestingly, antibody responses were only altered in patients with SLE treated with immunosuppressive therapies, whereas impairment of antigen-specific CD4+ and CD8+ T cell numbers was independent of medication. Patients with SLE also displayed reduced levels of circulating CXC motif chemokine ligands, CXCL9, CXCL10, CXCL11, and IFN-γ after secondary vaccination as well as downregulation of gene expression pathways indicative of compromised innate immune responses. Single-cell RNA-Seq analysis reveals that patients with SLE showed reduced levels of a vaccine-inducible monocyte population characterized by overexpression of IFN-response transcription factors. Thus, although 2 doses of BNT162b2 induced relatively robust immune responses in patients with SLE, our data demonstrate impairment of both innate and adaptive immune responses relative to HC, highlighting a need for population-specific vaccination studies.

Evolutionarily conserved mechanisms regulating stress-induced neutrophil redistribution in fish.

Stress may pose a serious challenge to immune homeostasis. Stress however also may prepare the immune system for challenges such as wounding or infection, which are likely to happen during a fight or flight stress response. In common carp (Cyprinus carpio L.) we studied the stress-induced redistribution of neutrophils into circulation, and the expression of genes encoding CXC chemokines known to be involved in the regulation of neutrophil retention (CXCL12) and redistribution (CXCL8), and their receptors (CXCR4 and CXCR1-2, respectively) in blood leukocytes and in the fish hematopoietic organ - the head kidney. The potential involvement of CXC receptors and stress hormone receptors in stress-induced neutrophil redistribution was determined by an in vivo study with selective CXCR inhibitors and antagonists of the receptors involved in stress regulation: glucocorticoid/mineralocorticoid receptors (GRs/MRs), adrenergic receptors (ADRs) and the melanocortin 2 receptor (MC2R). The stress-induced increase of blood neutrophils was accompanied by a neutrophil decrease in the hematopoietic organs. This increase was cortisol-induced and GR-dependent. Moreover, stress upregulated the expression of genes encoding CXCL12 and CXCL8 chemokines, their receptors, and the receptor for granulocytes colony-stimulation factor (GCSFR) and matrix metalloproteinase 9 (MMP9). Blocking of the CXCR4 and CXCR1 and 2 receptors with selective inhibitors inhibited the stress-induced neutrophil redistribution and affected the expression of genes encoding CXC chemokines and CXCRs as well as GCSFR and MMP9. Our data demonstrate that acute stress leads to the mobilization of the immune system, characterized by neutrophilia. CXC chemokines and CXC receptors are involved in this stress-induced redistribution of neutrophils from the hematopoietic tissue into the peripheral blood. This phenomenon is directly regulated by interactions between cortisol and the GR/MR. Considering the pivotal importance of neutrophilic granulocytes in the first line of defense, this knowledge is important for aquaculture, but will also contribute to the mechanisms involved in the stress-induced perturbation in neutrophil redistribution as often observed in clinical practice.

Epigenetic Mechanism of SETD1B-mediated Histone Methylation in Cognitive Impairment Induced by Sevoflurane Anesthesia in Neonatal Mice

Sevoflurane (Sev) anesthesia is associated with cognitive deficits and neurotoxicity. This study explores the epigenetic mechanism of SET domain containing 1B (SETD1B) in Sev-induced cognitive impairment in neonatal mice. Neonatal mice (C57BL/6, n = 72) were exposed to 3% Sev for 2 h per day at P6, 7, and 8, and the control neonatal mice were only separated from the mother for 2 h. The mice were divided into groups of 12 individuals, with an equal number of male and female mice in each group. Mice were intraperitoneally injected with adenovirus-packaged SETD1B overexpression vector. Behavioral tests (Morris water maze, open field test, T-maze, novel object recognition, etc.) were performed at P30. Mouse hippocampal neuronal cells were cultured in vitro. SETD1B, C-X-C motif chemokine receptor 4 (CXCR4), NLR family pyrin domain containing 1 (NLRP1), Cleaved Caspase1, and GSDMD-N expressions in hippocampal tissues or cells were determined by quantitative real-time polymerase chain reaction and Western blot. SETD1B and histone H3 lysine 4 methylation (H3K4me1, H3K4me2, and H3K4me3) enrichment on the CXCR4 promoter was analyzed by ChIP. Sev insulted cognitive impairment and diminished SETD1B expression in mouse hippocampal tissues. SETD1B overexpression mitigated cognitive impairment, enhanced H3K4me3 levels in hippocampal tissues, and restrained hippocampal neuronal pyroptosis. SETD1B increased CXCR4 expression by elevating the H3K4me3 level on the CXCR4 promoter, thereby curbing NLRP1/Caspase1-mediated hippocampal neuronal pyroptosis. To conclude, SETD1B enhances CXCR4 expression by elevating the H3K4me3 level on the CXCR4 promoter, thereby suppressing NLRP1/Caspase1-triggered hippocampal neuronal pyroptosis and alleviating Sev-induced cognitive impairment in neonatal mice.

Role of the CXCR4-Gnαq-Plcβ signaling pathway in the pathogenesis of collagen-induced arthritis in rats

Rheumatoid arthritis (RA) is a chronic autoimmune disease in which immune cells and inflammatory cytokines are abnormally activated, leading to immunoregulatory dysfunction in the body and triggering systemic inflammatory responses. The interaction between CXC chemokine receptor 4 (CXCR4) and heterotrimeric G-protein α-subunit Gαq (Gnαq) activates phospholipase Cβ (PLCβ), which influences the expression of downstream effectors and participates widely in the onset and development of various diseases, thus suggesting the potential involvement of these molecules in RA pathogenesis. Therefore, the present study aimed to determine whether the CXCR4-Gnαq-PLCβ signaling pathway participates in the onset and development of RA. Using a collagen-induced arthritis (CIA) rat model, we found that compared with the control (healthy) rat group, CIA rats exhibited highly time-dependent arthritis, with the maximum arthritis score occurring in week 3. In contrast to the splenic and joint tissue of control rats, CIA rats showed obvious hyperplasia in the lymphoid white pulp and main germination centers of the spleen, narrowing of joint cavities, and inflammatory cellular infiltration on articular surfaces. The serum levels of expression of IL-1β, IL-4, IL-6, and TNF-α were significantly elevated (P < 0.05, P < 0.01). Core genes of the CXCR4-Gnαq-PLCβ pathway, namely CXCR4, Gnαq, PLCβ1, MMP1, and MMP3, also showed a significant increase in mRNA and protein expression levels (P < 0.05, P < 0.01). Proteins related to the CXCR4-Gnαq-PLCβ pathway were mainly localized to the red and white pulp regions in the spleen as well as in stromal, endothelial, and subdifferentiated synovial cells in the joints. These results indicated that CXCR4 is dependent on Gnαq for inducing the expression of PLCβ1 and stimulation of secretion of inflammatory cytokines by inflammatory cells. This consequently affects the expression of matrix metalloproteinases (MMPs), which serve as downstream effectors, thereby promoting RA pathogenesis. Our findings play an important role in elucidating the mechanisms of the onset and development of RA.

Enlarged perivascular spaces are associated with white matter injury, cognition and inflammation in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

Enlarged perivascular spaces have been previously reported in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, but their significance and pathophysiology remains unclear. We investigated associations of white matter enlarged perivascular spaces with classical imaging measures, cognitive measures and plasma proteins to better understand what enlarged perivascular spaces represent in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and whether radiographic measures of enlarged perivascular spaces would be of value in future therapeutic discovery studies for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. Twenty-four individuals with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and 24 age- and sex-matched controls were included. Disease status was determined based on the presence of NOTCH3 mutation. Brain imaging measures of white matter hyperintensity, brain parenchymal fraction, white matter enlarged perivascular space volumes, clinical and cognitive measures as well as plasma proteomics were used in models. White matter enlarged perivascular space volumes were calculated via a novel, semiautomated pipeline, and levels of 7363 proteins were quantified in plasma using the SomaScan assay. The relationship of enlarged perivascular spaces with global burden of white matter hyperintensity, brain atrophy, functional status, neurocognitive measures and plasma proteins was modelled with linear regression models. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and control groups did not exhibit differences in mean enlarged perivascular space volumes. However, increased enlarged perivascular space volumes in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy were associated with increased white matter hyperintensity volume (β = 0.57, P = 0.05), Clinical Dementia Rating Sum-of-Boxes score (β = 0.49, P = 0.04) and marginally with decreased brain parenchymal fraction (β = -0.03, P = 0.10). In interaction term models, the interaction term between cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy disease status and enlarged perivascular space volume was associated with increased white matter hyperintensity volume (β = 0.57, P = 0.02), Clinical Dementia Rating Sum-of-Boxes score (β = 0.52, P = 0.02), Mini-Mental State Examination score (β = -1.49, P = 0.03) and marginally with decreased brain parenchymal fraction (β = -0.03, P = 0.07). Proteins positively associated with enlarged perivascular space volumes were found to be related to leukocyte migration and inflammation, while negatively associated proteins were related to lipid metabolism. Two central hub proteins were identified in protein networks associated with enlarged perivascular space volumes: CXC motif chemokine ligand 8/interleukin-8 and C-C motif chemokine ligand 2/monocyte chemoattractant protein 1. The levels of CXC motif chemokine ligand 8/interleukin-8 were also associated with increased white matter hyperintensity volume (β = 42.86, P = 0.03), and levels of C-C motif chemokine ligand 2/monocyte chemoattractant protein 1 were further associated with decreased brain parenchymal fraction (β = -0.0007, P < 0.01) and Mini-Mental State Examination score (β = -0.02, P < 0.01) and increased Trail Making Test B completion time (β = 0.76, P < 0.01). No proteins were associated with all three studied imaging measures of pathology (brain parenchymal fraction, enlarged perivascular spaces, white matter hyperintensity). Based on associations uncovered between enlarged perivascular space volumes and cognitive functions, imaging and plasma proteins, we conclude that white matter enlarged perivascular space volumes may capture pathologies contributing to chronic brain dysfunction and degeneration in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

Caspase-8 activation regulates enterovirus D68 infection-induced inflammatory response and cell death

Enterovirus D68 (EV-D68) infection causes severe acute respiratory infection and severe neurological complications, such as acute flaccid myelitis (AFM), in children. However, although EV-D68 has pandemic potential, no effective drugs or vaccines are currently clinically available. Furthermore, EV-D68 infection-induced inflammatory response and cell death are not fully understood. In this study, we demonstrated that several inflammatory cytokines were upregulated in a multiplicity of infection (MOI) dependent manner in EV-D68-infected human rhabdomyosarcoma (RD) cells. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) confirmed that tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), C-C motif chemokine ligand-5 (CCL-5), and CXC motif chemokine ligand-5 (CXCL-5) mRNA levels were highly upregulated after EV-D68 infection. IL-1β processing and maturation mediated by caspase-8 was inhibited by the caspase-8 inhibitor Z-IETD-FMK. EV-D68 infection activates caspase-8 to mediate IL-1β maturation and secretion. Additionally, EV-D68 activated cell death-related proteins such as caspase-3, poly (ADP-ribose) polymerase 1 (PARP-1), phosphorylation of Mixed Lineage Kinase domain-like protein (pMLKL), and gasdermin E (GSDME). Thus, EV-D68 infection activates caspase-8, which triggers the necroptosis and apoptosis pathways. Overall, our data suggest that caspase-8 activation is associated with the inflammatory response and cell death in EV-D68-infected RD cells. This mechanism represents a novel target for the treatment of EV-D68 infection by inhibiting caspase-8 activation.

Exploring the Interplay of RUNX2 and CXCR4 in Melanoma Progression.

Overexpression of the Runt-related transcription factor 2 (RUNX2) has been reported in several cancer types, and the C-X-C motif chemokine receptor 4 (CXCR4) has an important role in tumour progression. However, the interplay between CXCR4 and RUNX2 in melanoma cells remains poorly understood. In the present study, we used melanoma cells and a RUNX2 knockout (RUNX2-KO) in vitro model to assess the influence of RUNX2 on CXCR4 protein levels along with its effects on markers associated with cell invasion and autophagy. Osteotropism was assessed using a 3D microfluidic model. Moreover, we assessed the impact of CXCR4 on the cellular levels of key cellular signalling proteins involved in autophagy. We observed that melanoma cells express both RUNX2 and CXCR4. Restored RUNX2 expression in RUNX2 KO cells increased the expression levels of CXCR4 and proteins associated with the metastatic process. The protein markers of autophagy LC3 and beclin were upregulated in response to increased CXCR4 levels. The CXCR4 inhibitor WZ811 reduced osteotropism and activated the mTOR and p70-S6 cell signalling proteins. Our data indicate that the RUNX2 transcription factor promotes the expression of the CXCR4 chemokine receptor on melanoma cells, which in turn promotes autophagy, cell invasiveness, and osteotropism, through the inhibition of the mTOR signalling pathway. Our data suggest that RUNX2 promotes melanoma progression by upregulating CXCR4, and we identify the latter as a key player in melanoma-related osteotropism.

Impact of plerixafor use in the mobilization of blood grafts for autologous hematopoietic cell transplantation.

Plerixafor (PLER), a reversible antagonist of the CXC chemokine receptor type 4, has been in clinical use for mobilization of blood grafts for autologous hematopoietic cell transplantation (AHCT) for about 15 years. Initially PLER was investigated in placebo-controlled trials with the granulocyte colony-stimulating factor (G-CSF) filgrastim. It has also been used in combination with chemotherapy plus G-CSF in patients who had failed a previous mobilization attempt or appeared to mobilize poorly with current mobilization (preemptive use). This review summarizes what is known regarding addition of PLER to standard mobilization regimens. PLER increases mobilization of CD34+ cells, decreases the number of apheresis sessions needed to achieve collection targets and increases the proportion of patients who can proceed to AHCT. It appears also to increase the amount of various lymphocyte subsets in the grafts collected. In general, hematologic recovery after AHCT has been comparable to patients mobilized without PLER, although slower platelet recovery has been observed in some studies of patients who mobilize poorly. In phase III studies, long-term outcome has been comparable to patients mobilized without PLER. This also appears to be the case in patients receiving plerixafor for poor or suboptimal mobilization of CD34+ cells. In practice, PLER is safe and has not been shown to increase tumor cell mobilization.

Dysregulated CXCL12 expression in osteoblasts promotes B-lymphocytes preferentially homing to the bone marrow in MRL/lpr mice

Objective: Todetect the abnormal distribution of B-lymphocytes between peripheral and bone marrow (BM) compartments and explore the mechanism of abnormal chemotaxis of B-lymphocytes in lupus subjects. Methods: The proportions of CXC chemokine receptor (CXCR)4+ B cells and CFDA-labeled MRL/lpr-derived B cells were detected by flow cytometry. The levels of CXC chemokine ligand (CXCL)12in peripheral blood (PB)were measured by ELISA. The migrated B cells to osteoblasts (OBs) was measured by transwell migration assay. The relative spatial position of B cells, OBs and CXCL12 was presented by Immunofluorescence assay. Results: Firstly, we found that the percentage of CXCR4+ B cells was lower in PB and higher in the BM from both MRL/lpr mice and patientswith Systemic lupus erythematosus (SLE). Secondly, OBs from MRL/lpr mice produced more CXCL12 than that from C57BL/6 mice. Besides, MRL/lpr-derived OBs demonstrated more potent chemotactic ability toward B-lymphocytes than control OBs by vitro an vivo. Additionally, more B-lymphocytes were found to co-localize with OBs within the periosteal zone of bone in MRL/lpr mice. Lastly, the percentages of CXCR4+B cells were found to be negatively correlated with serum Immunoglobulin (Ig) G concentration, moreover, BM CXCL12 levels were found to be positively correlated with SLE disease activity index Score and negatively correlated with serum Complement3 (C3) concentration. Conclusions: our results indicated that there is a shifted distribution of B-lymphocytes between BM and peripheral compartments in both SLE patients and MRL/lpr mice. Besides, the up-regulated levels of CXCL12 in OBs was indicated to contribute to the enhanced chemotactic migration and anchorage of B-lymphocytes to OBs.

Ultrasonic microbubbles promote mesenchymal stem cell homing to the fibrotic liver via upregulation of CXCR4 expression

ObjectiveTo investigate the mechanism of ultrasound microbubbles (UTMB) promoting stem cells homing to fibrotic liver.MethodsBone marrow derived mesenchymal stem cells (BMSCs) were divided into 5 groups with or without ultrasound microbubbles and continuously irradiated with ultrasound conditions of frequency 1 MHZ and output power 0.6 W/cm2 for different times, and then injected into a mouse model of liver fibrosis through the tail vein with or without ultrasound microbubbles, with sound intensity. The effect of ultrasound microbubbles on MSC expression of CXC chemokine receptor 4 (CXCR4) and homing fibrotic liver was evaluated by flow cytometry (FCM), western blot (WB) and immunohistochemistry (IHC) analysis.ResultsThe level of CXCR4 expression was significantly higher in the ultrasound microbubble group than in the non-intervention group (P < 0.05), and the number of MSC and the rate of CXCR4 receptor positivity in the ultrasound microbubble-treated liver tissues were significantly higher than in the non-intervention group (P < 0.01).ConclusionUltrasonic microbubbles can promote the expression of CXCR4 on the surface of MSCs, thus improving the homing rate of MSCs in fibrotic liver.