Rapid Mobilization Reveals a Highly Engraftable Hematopoietic Stem Cell.

Hematopoietic stem cell transplantation is a potential curative therapy for malignant and nonmalignant diseases. Improving the efficiency of stem cell collection and the quality of the cells acquired can broaden the donor pool and improve patient outcomes. We developed a rapid stem cell mobilization regimen utilizing a unique CXCR2 agonist, GROß, and the CXCR4 antagonist AMD3100. A single injection of both agents resulted in stem cell mobilization peaking within 15 min that was equivalent in magnitude to a standard multi-day regimen of granulocyte colony-stimulating factor (G-CSF). Mechanistic studies determined that rapid mobilization results from synergistic signaling on neutrophils, resulting in enhanced MMP-9 release, and unexpectedly revealed genetic polymorphisms in MMP-9 that alter activity. This mobilization regimen results in preferential trafficking of stem cells that demonstrate a higher engraftment efficiency than those mobilized by G-CSF. Our studies suggest a potential new strategy for the rapid collection of an improved hematopoietic graft.

Age-related changes in the local milieu of inflamed tissues cause aberrant neutrophil trafficking and subsequent remote organ damage.

Aging is associated with dysregulated immune functions. Here, we investigated the impact of age on neutrophil diapedesis. Using confocal intravital microscopy, we found that in aged mice, neutrophils adhered to vascular endothelium in inflamed tissues but exhibited a high frequency of reverse transendothelial migration (rTEM). This retrograde breaching of the endothelium by neutrophils was governed by enhanced production of the chemokine CXCL1 from mast cells that localized at endothelial cell (EC) junctions. Increased EC expression of the atypical chemokine receptor 1 (ACKR1) supported this pro-inflammatory milieu in aged venules. Accumulation of CXCL1 caused desensitization of the chemokine receptor CXCR2 on neutrophils and loss of neutrophil directional motility within EC junctions. Fluorescent tracking revealed that in aged mice, neutrophils undergoing rTEM re-entered the circulation and disseminated to the lungs where they caused vascular leakage. Thus, neutrophils stemming from a local inflammatory site contribute to remote organ damage, with implication to the dysregulated systemic inflammation associated with aging.

A Neutrophil Timer Coordinates Immune Defense and Vascular Protection.

Neutrophils eliminate pathogens efficiently but can inflict severe damage to the host if they over-activate within blood vessels. It is unclear how immunity solves the dilemma of mounting an efficient anti-microbial defense while preserving vascular health. Here, we identify a neutrophil-intrinsic program that enabled both. The gene Bmal1 regulated expression of the chemokine CXCL2 to induce chemokine receptor CXCR2-dependent diurnal changes in the transcriptional and migratory properties of circulating neutrophils. These diurnal alterations, referred to as neutrophil aging, were antagonized by CXCR4 (C-X-C chemokine receptor type 4) and regulated the outer topology of neutrophils to favor homeostatic egress from blood vessels at night, resulting in boosted anti-microbial activity in tissues. Mice engineered for constitutive neutrophil aging became resistant to infection, but the persistence of intravascular aged neutrophils predisposed them to thrombo-inflammation and death. Thus, diurnal compartmentalization of neutrophils, driven by an internal timer, coordinates immune defense and vascular protection.

Distinct Compartmentalization of the Chemokines CXCL1 and CXCL2 and the Atypical Receptor ACKR1 Determine Discrete Stages of Neutrophil Diapedesis.

Neutrophils require directional cues to navigate through the complex structure of venular walls and into inflamed tissues. Here we applied confocal intravital microscopy to analyze neutrophil emigration in cytokine-stimulated mouse cremaster muscles. We identified differential and non-redundant roles for the chemokines CXCL1 and CXCL2, governed by their distinct cellular sources. CXCL1 was produced mainly by TNF-stimulated endothelial cells (ECs) and pericytes and supported luminal and sub-EC neutrophil crawling. Conversely, neutrophils were the main producers of CXCL2, and this chemokine was critical for correct breaching of endothelial junctions. This pro-migratory activity of CXCL2 depended on the atypical chemokine receptor 1 (ACKR1), which is enriched within endothelial junctions. Transmigrating neutrophils promoted a self-guided migration response through EC junctions, creating a junctional chemokine "depot" in the form of ACKR1-presented CXCL2 that enabled efficient unidirectional luminal-to-abluminal migration. Thus, CXCL1 and CXCL2 act in a sequential manner to guide neutrophils through venular walls as governed by their distinct cellular sources.

CXCR2 inhibition in G-MDSCs enhances CD47 blockade for melanoma tumor cell clearance.

The use of colony-stimulating factor-1 receptor (CSF1R) inhibitors has been widely explored as a strategy for cancer immunotherapy due to their robust depletion of tumor-associated macrophages (TAMs). While CSF1R blockade effectively eliminates TAMs from the solid tumor microenvironment, its clinical efficacy is limited. Here, we use an inducible CSF1R knockout model to investigate the persistence of tumor progression in the absence of TAMs. We find increased frequencies of granulocytic myeloid-derived suppressor cells (G-MDSCs) in the bone marrow, throughout circulation, and in the tumor following CSF1R deletion and loss of TAMs. We find that G-MDSCs are capable of suppressing macrophage phagocytosis, and the elimination of G-MDSCs through CXCR2 inhibition increases macrophage capacity for tumor cell clearance. Further, we find that combination therapy of CXCR2 inhibition and CD47 blockade synergize to elicit a significant anti-tumor response. These findings reveal G-MDSCs as key drivers of tumor immunosuppression and demonstrate their inhibition as a potent strategy to increase macrophage phagocytosis and enhance the anti-tumor efficacy of CD47 blockade in B16-F10 melanoma.

Targeting ESE3/EHF With Nifurtimox Inhibits CXCR2+ Neutrophil Infiltration and Overcomes Pancreatic Cancer Resistance to Chemotherapy and Immunotherapy.

BACKGROUND & AIMS: Because pancreatic cancer responds poorly to chemotherapy and immunotherapy, it is necessary to identify novel targets and compounds to overcome resistance to treatment. METHODS: This study analyzed genomic single nucleotide polymorphism sequencing, single-cell RNA sequencing, and spatial transcriptomics. Ehf-knockout mice, KPC (LSL-KrasG12D/+, LSL-Trp53R172H/+ and Pdx1-Cre) mice, CD45.1+ BALB/C nude mice, and CD34+ humanized mice were also used as subjects. Multiplexed immunohistochemistry and flow cytometry were performed to investigate the proportion of tumor-infiltrated C-X-C motif chemokine receptor 2 (CXCR2)+ neutrophils. In addition, multiplexed cytokines assays and chromatin immunoprecipitation assays were used to examine the mechanism. RESULTS: The TP53 mutation-mediated loss of tumoral EHF increased the recruitment of CXCR2+ neutrophils, modulated their spatial distribution, and further induced chemo- and immunotherapy resistance in clinical cohorts and preclinical syngeneic mice models. Mechanistically, EHF deficiency induced C-X-C motif chemokine ligand 1 (CXCL1) transcription to enhance in vitro and in vivo CXCR2+ neutrophils migration. Moreover, CXCL1 or CXCR2 blockade completely abolished the effect, indicating that EHF regulated CXCR2+ neutrophils migration in a CXCL1-CXCR2-dependent manner. The depletion of CXCR2+ neutrophils also blocked the in vivo effects of EHF deficiency on chemotherapy and immunotherapy resistance. The single-cell RNA-sequencing results of PDAC treated with Nifurtimox highlighted the therapeutic significance of Nifurtimox by elevating the expression of tumoral EHF and decreasing the weightage of CXCL1-CXCR2 pathway within the microenvironment. Importantly, by simultaneously inhibiting the JAK1/STAT1 pathway, it could significantly suppress the recruitment and function of CXCR2+ neutrophils, further sensitizing PDAC to chemotherapy and immunotherapies. CONCLUSIONS: The study demonstrated the role of EHF in the recruitment of CXCR2+ neutrophils and the promising role of Nifurtimox in sensitizing pancreatic cancer to chemotherapy and immunotherapy.

IL-17A-neutralizing antibody ameliorates inflammation and fibrosis in rosacea by antagonizing the CXCL5/CXCR2 axis.

Rosacea is a chronic inflammatory skin disorder that can lead to fibrosis. However, the mechanisms underlying fibrosis in the later stages of rosacea have been less thoroughly investigated. Interleukin-17A (IL-17A) has been implicated in both inflammation and organ fibrosis; however, the effectiveness and mechanism of IL-17A-neutralizing antibodies in the later stages of rosacea-related fibrosis remain unclear. In this study, we induced rosacea-like lesions in mice using LL-37 and administered IL-17A-neutralizing antibodies. The results indicated that the IL-17A-neutralizing antibodies alleviated skin damage, reduced skin thickness, and decreased the secretion of inflammatory factors (TNF-α, CAMP, TLR4, P-NF-kB), angiogenesis-related factors (CD31, VEGF), and the TGF-ß1 signaling pathway, along with factors associated with epithelial-mesenchymal transition and the deposition of fibrosis-related proteins (COL1) in the rosacea-like mouse models. Furthermore, the IL-17A-neutralizing antibodies effectively diminished the expression of IL-17, IL-17R, CXCL5, and CXCR2 in the skin. Our findings demonstrate that IL-17A-neutralizing antibodies inhibit the activation of the CXCL5/CXCR2 axis in rosacea-like skin tissue, thereby ameliorating inflammation and fibrosis associated with the condition.

Mast cells contribute to T-cell accumulation in the bronchoalveolar space in mice with IL-33-induced airway inflammation.

Interleukin (IL)-33 released from airway epithelial cells plays a vital role in shaping type 2 immune responses by binding to the ST2 receptor present in many immune cells, including mast cells (MCs). Intranasal administration of IL-33 in mice induces type 2 lung inflammation, an increase in lung MC progenitors, and transepithelial migration of leukocytes to the bronchoalveolar space. The aim of this study was to determine the contribution of MCs in IL-33-induced lung pathology. Four daily intranasal administrations of IL-33 reduced spirometry-like lung function parameters, induced airway hyperresponsiveness, and increased leukocytes in bronchoalveolar lavage fluid (BAL) in an ST2-dependent manner. MC-deficient (Cpa3cre/+) mice, which lack MCs, had intact spirometry-like lung function but slightly reduced airway hyperresponsiveness, possibly related to reduced IL-33 or serotonin. Strikingly, Cpa3cre/+ mice exposed to IL-33 had 50% reduction in BAL T-cells, and CXCL1 and IL-33 were reduced in the lung. Intranasal IL-33 induced CXCR2 expression in T-cells in a MC-independent fashion. Furthermore, IL-33-induced lung MCs were immunopositive for CXCL1 and localized in the epithelium of wild-type mice. These results suggest that MCs are required to sustain intact lung IL-33 and CXCL1 levels in mice with IL-33-induced airway inflammation, thereby facilitating T-cell accumulation in the bronchoalveolar space.

Association of interleukin-17A and chemokine/vascular endothelial growth factor-induced angiogenesis in newly diagnosed patients with bladder cancer.

BACKGROUND: The human interleukin-17 (IL-17) family comprises IL-17A to IL-17 F; their receptors are IL-17RA to IL-17RE. Evidence revealed that these cytokines can have a tumor-supportive or anti-tumor impact on human malignancies. The purpose of this study was to assess the expression of CXCR2, IL-17RA, and IL-17RC genes at the mRNA level as well as tissue and serum levels of IL-17A, vascular endothelial growth factor (VEGF), and transforming growth factor ß (TGF-ß) in patients with bladder cancer (BC) compared to control. RESULTS: This study showed that gene expression of IL-17RA, IL-17RC, and CXCR2 in the tumoral tissue of BC patients was significantly upregulated compared with normal tissue. The findings disclosed a significant difference in the serum and tissue concentrations of IL-17A, VEGF, and TGF-ß between the patient and the control groups, as well as tumor and normal tissues. CONCLUSION: This study reveals notable dysregulation of CXCR2, IL-17RA, and IL-17RC genes, alongside changes in IL-17A, VEGF, and TGF-ß levels in patients with BC than in controls. These findings indicate their possible involvement in BC development and their potential as diagnostic and therapeutic targets.

Ectopic CXCR2 expression cells improve the anti-tumor efficiency of CAR-T cells and remodel the immune microenvironment of pancreatic ductal adenocarcinoma.

BACKGROUND: Recent progressions in CAR-T cell therapy against pancreatic ductal adenocarcinoma (PDAC) remain disappointing, which are partially attributed to the immunosuppressive microenvironment including macrophage-mediated T cell repletion. METHODS: We first characterized the expression patterns of macrophage-relevant chemokines and identified CXCR2 as the key factor regulating T cell trafficking and tumor-specific accumulation in PDAC microenvironment. After that, we synthesized and introduced a CXCR2 expression cascade into Claudin18.2 CAR-T cells and compared the behaviors of CAR-T cells in vitro and in vivo. The therapeutic potential of CXCR2 CAR-T was evaluated in two different allogeneic models: subcutaneous allografts and metastatic PDAC models. RESULTS: The results showed that CXCR2 CAR-T not only reduced the size of allografted PDAC tumors, but also completely eliminated the formation of metastases. Lastly, we investigated the tumor tissues and found that expression of ectopic CXCR2 significantly improved tumor-targeted infiltration and residence of T cells and reduced the presence of MDSCs and CXCR2 + macrophages in PDAC microenvironment. CONCLUSION: Our studies suggested that ectopic CXCR2 played a significant and promising role in improving the efficiency of CAR-T therapy against primary and metastatic PDAC and partially reversed the immune-suppressive microenvironment.

The CXCR2 chemokine receptor: A new target for gastric cancer therapy.

Gastric cancer (GC) is one of the most common malignant tumors in the world, and current treatments are still based on surgery and drug therapy. However, due to the complexity of immunosuppression and drug resistance, the treatment of gastric cancer still faces great challenges. Chemokine receptor 2 (CXCR2) is one of the most common therapeutic targets in targeted therapy. As a G protein-coupled receptor, CXCR2 and its ligands play important roles in tumorigenesis and progression. The abnormal expression of these genes in cancer plays a decisive role in the recruitment and activation of white blood cells, angiogenesis, and cancer cell proliferation, and CXCR2 is involved in various stages of tumor development. Therefore, interfering with the interaction between CXCR2 and its ligands is considered a possible target for the treatment of various tumors, including gastric cancer.

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

BACKGROUND: The 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. METHODS: Multiple 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-Cxcr2 eCKO mice), as well as in glomerular endothelial cells (GECs), cultured in high glucose conditions. RESULTS: CXCR2 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 Cxcr2 L/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. CONCLUSIONS: Taken 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.

Systematic assessment of chemokine ligand bias at the human chemokine receptor CXCR2 indicates G protein bias over ß-arrestin recruitment and receptor internalization.

BACKGROUND: The human CXC chemokine receptor 2 (CXCR2) is a G protein-coupled receptor (GPCR) interacting with multiple chemokines (i.e., CXC chemokine ligands CXCL1-3 and CXCL5-8). It is involved in inflammatory diseases as well as cancer. Consequently, much effort is put into the identification of CXCR2 targeting drugs. Fundamental research regarding CXCR2 signaling is mainly focused on CXCL8 (IL-8), which is the first and best described high-affinity ligand for CXCR2. Much less is known about CXCR2 activation induced by other chemokines and it remains to be determined to what extent potential ligand bias exists within this signaling system. This insight might be important to unlock new opportunities in therapeutic targeting of CXCR2. METHODS: Ligand binding was determined in a competition binding assay using labeled CXCL8. Activation of the ELR + chemokine-induced CXCR2 signaling pathways, including G protein activation, ß-arrestin1/2 recruitment, and receptor internalization, were quantified using NanoBRET-based techniques. Ligand bias within and between these pathways was subsequently investigated by ligand bias calculations, with CXCL8 as the reference CXCR2 ligand. Statistical significance was tested through a one-way ANOVA followed by Dunnett's multiple comparisons test. RESULTS: All chemokines (CXCL1-3 and CXCL5-8) were able to displace CXCL8 from CXCR2 with high affinity and activated the same panel of G protein subtypes (Gαi1, Gαi2, Gαi3, GαoA, GαoB, and Gα15) without any statistically significant ligand bias towards any one type of G protein. Compared to CXCL8, all other chemokines were less potent in ß-arrestin1 and -2 recruitment and receptor internalization while equivalently activating G proteins, indicating a G protein activation bias for CXCL1,-2,-3,-5,-6 and CXCL7. Lastly, with CXCL8 used as reference ligand, CXCL2 and CXCL6 showed ligand bias towards ß-arrestin1/2 recruitment compared to receptor internalization. CONCLUSION: This study presents an in-depth analysis of signaling bias upon CXCR2 stimulation by its chemokine ligands. Using CXCL8 as a reference ligand for bias index calculations, no ligand bias was observed between chemokines with respect to activation of separate G proteins subtypes or recruitment of ß-arrestin1/2 subtypes, respectively. However, compared to ß-arrestin recruitment and receptor internalization, CXCL1-3 and CXCL5-7 were biased towards G protein activation when CXCL8 was used as reference ligand.

Neuroprotective Effects of CXCR2 Antagonist SB332235 on Traumatic Brain Injury Through Suppressing NLRP3 Inflammasome.

The inflammatory process mediated by nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain comprising 3 (NLRP3) inflammasome plays a predominant role in the neurological dysfunction following traumatic brain injury (TBI). SB332235, a highly selective antagonist of chemokine receptor 2 (CXCR2), has been demonstrated to exhibit anti-inflammatory properties and improve neurological outcomes in the central nervous system. We aimed to determine the neuroprotective effects of SB332235 in the acute phase after TBI in mice and to elucidate its underlying mechanisms. Male C57BL/6J animals were exposed to a controlled cortical impact, then received 4 doses of SB332235, with the first dose administered at 30 min after TBI, followed by additional doses at 6, 24, and 30 h. Neurological defects were assessed by the modified neurological severity score, while the motor function was evaluated using the beam balance and open field tests. Cognitive performance was evaluated using the novel object recognition test. Brain tissues were collected for pathological, Western blot, and immunohistochemical analyses. The results showed that SB332235 significantly ameliorated TBI-induced deficits, including motor and cognitive impairments. SB332235 administration suppressed expression of both CXCL1 and CXCR2 in TBI. Moreover, SB332235 substantially mitigated the augmented expression levels and activation of the NLRP3 inflammasome within the peri-contusional cortex induced by TBI. This was accompanied by the blocking of subsequent production of pro-inflammatory cytokines. Additionally, SB332235 hindered microglial activity induced by TBI. These findings confirmed the neuroprotective effects of SB332235 against TBI, and the involved mechanisms were in part due to the suppression of NLRP3 inflammasome activity. This study suggests that SB332235 may act as an anti-inflammatory agent to improve functional outcomes in brain injury when applied clinically.

Clinicopathological significance of microsatellite instability and immune escape mechanism in patients with gastric solid-type poorly differentiated adenocarcinoma.

BACKGROUND: In gastric solid-type poorly differentiated adenocarcinoma (PDA), the role of microsatellite instability and immune escape mechanism remains unclear. The current study aimed to elucidate the clinical significance of mismatch repair (MMR) status, genome profile, C-X-C motif chemokine receptor 2 (CXCR2) expression, and myeloid-derived suppressor cell (MDSC) infiltration in solid-type PDA. METHODS: In total, 102 primary solid-type PDA cases were retrieved, and classified into 46 deficient-MMR (dMMR) and 56 proficient-MMR (pMMR) cases based on immunohistochemistry (IHC) and polymerase chain reaction-based molecular testing results. The mRNA expression profiles (NanoString nCounter Assay) of stage-matched dMMR (n = 6) and pMMR (n = 6) cases were examined. The CXCR2 expression and MDSC infiltration (CD11b- and CD33-positive cells) were investigated via IHC in all solid-type PDA cases. RESULTS: mRNA analysis revealed several differentially expressed genes and differences in biological behavior between the dMMR (n = 46) and pMMR (n = 56) groups. In the multivariate analysis, the dMMR status was significantly associated with a longer disease-free survival (hazard ratio = 5.152, p = 0.002) and overall survival (OS) (hazard ratio = 5.050, p = 0.005). CXCR2-high expression was significantly correlated with a shorter OS in the dMMR group (p = 0.018). A high infiltration of CD11b- and CD33-positive cells was significantly correlated with a shorter OS in the pMMR group (p = 0.022, 0.016, respectively). CONCLUSIONS: dMMR status can be a useful prognostic predictor, and CXCR2 and MDSCs can be novel therapeutic targets in patients with solid-type PDA.

Molecular Determination of Tumor Necrosis Factor-alpha, Interleukin-8, Interleukin-10, and C-X-C Chemokine Receptor-2 Genetic Variations and their Association with Disease Susceptibility and Mortality in COVID-19 Patients.

Background: Altered cytokine levels have been associated with poor outcomes among COVID-19 patients. TNF-α, IL-8 and IL-10 are key cytokines in COVID-19 pathogenesis, and CXCR-2 is a major chemokine receptor involved in inflammatory response. Polymorphisms in the genes of these proteins are proposed to influence disease outcomes. In this study, we aimed to find out the association of genetic polymorphisms in TNF-α, IL-8, IL-10 and CXCR-2 genes with susceptibility to and mortality of COVID-19. Methods: The present case-control study was conducted on 230 subjects, among whom 115 were clinically diagnosed and RT-PCR-confirmed COVID-19 patients and 115 healthy control subjects. The polymorphisms in TNFα -308 G>A (rs1800629), IL-8 -251T>A (rs4073), CXCR2 +785 C>T (rs2230054) genes were detected by ARMS -PCR assay whereas for IL-10 (-1082 G>A), rs1800896 G>A allele-specific PCR assay was used and their association with COVID-19 susceptibility and mortality was estimated by multivariate analysis. The results were analyzed for risk of infection and mortality through different inheritance models. Results: Frequencies of TNF-α rs1800629 GA, AA, IL-8 rs4073 TA, AA, IL-10 (-1082 G>A), rs1800896 GA and GG, and CXCR2 rs2230054 CT genotypes were significantly higher in COVID-19 patients compared to the control group (p < 0.05). Furthermore, COVID-19 patients had a higher frequency of the polymorphic A allele of TNF-α, the A allele of IL-8, the G allele of IL-10, and the T allele of CXCR2. The risk of susceptibility to COVID-19 was significantly associated with TNF-α rs1800629 GA, GA+AA genotypes and the A allele, IL-8 rs4073 TA, AA genotypes and A allele, IL-10 rs1800872 GA and CC genotypes and C allele, and CXCR2 rs2230054 CT and CT+CC genotypes. TNF-α-GA and AA genotypes and A allele, IL-8 TA and AA genotypes and A allele and CXCR-2 CC and CT genotypes have significant associations with mortality risk in COVID-19 patients, while GA and GG genotypes of the IL-10 are shown to confer significant protection against mortality from COVID-19. Conclusion: The findings of this study provide important insights into the COVID-19 disease and susceptibility risk. The polymorphisms in TNFα -308 G>A (rs1800629), IL-8 -251T>A (rs4073), IL-10 (-1082 G>A), rs1800896 and CXCR2 +785 C>T (rs2230054) are associated with the risk of susceptibility to COVID-19 and with mortality in COVID-19 patients. Further studies with larger sample sizes are necessary to confirm our findings.

VDR, CXCR1, CXCR2, PSCA Polymorphisms and Recurrent Urinary Tract Infections in Women: Genetic Association Study.

INTRODUCTION AND HYPOTHESIS: Urinary tract infection (UTI) is one of the most common human infections. Evidence suggests that there might be a genetic predisposition to UTI. Previous small candidate gene studies have suggested that common variants in genes involved in the immune response to UTI could increase susceptibility to the development of recurrent UTI (rUTI). The objective was to conduct a gene association study to replicate previous gene association studies identifying single nucleotide polymorphisms (SNPs) putatively associated with rUTI in adult women. METHODS: Women with a history of rUTI and healthy controls were recruited (n = 1,008) from gynaecology outpatient clinics. Participants completed a signed consent form and questionnaire for phenotyping. DNA was extracted from blood or saliva samples for each participant. Putative associated SNPs were identified from a comprehensive systematic review of prior gene association studies. Primers for each selected SNP were designed, and genotyping was conducted using a competitive polymerase chain reaction (PCR) method. The Chi-squared test was used to assess the association between each variant and rUTI. Genotyping quality was assessed by checking for deviation from Hardy-Weinberg equilibrium. RESULTS: We found no association between SNPs tested in the VDR (p = 0.16, p = 0.09, p = 0.36), CXCR1 (p = 0.09), CXCR2 (p = 0.39), PSCA (p = 0.74) genes, and rUTI in adult women. CONCLUSIONS: To our knowledge, this is the largest study to date, finding no significant associations. Previously reported positive associations may have been due to type 1 error, or genotyping errors. Future studies should adjust for confounders and employ adequate sample sizes. A greater understanding of the genetic components associated with rUTI may influence future treatment guidelines and screening for susceptible patients.

Selective anti-CXCR2 receptor blockade by AZD5069 inhibits CXCL8-mediated pro-tumorigenic activity in human thyroid cancer cells in vitro.

BACKGROUND: Thyroid cancer is the most common endocrine malignancy. Current therapies are successful, however some patients progress to therapeutically refractive disease. The immunotherapeutic potential of the CXCL8-chemokine/CXCR2-chemokine-receptor system is currently being explored in numerous human cancers. This study aimed to evaluate if the targeting of CXCR2 by its selective antagonist, AZD5069, could modulate CXCL8-mediated pro-tumorigenic effects in thyroid-cancer (TC) cells in vitro. METHODS: Normal human primary thyroid cells (NHT) and TC cell lines TPC-1 (RET/PTC), BCPAP, 8505C and 8305C (BRAFV600e) were treated with AZD5069 (100 pM-10 µM) over a time-course. Viability and proliferation were assessed by WST-1 and crystal violet assays. CXCL8 and CXCR2 mRNA were evaluated by RT-PCR. CXCL8-protein concentrations were measured in cell culture supernatants by ELISA. CXCR2 on cell surface was evaluated by flow-cytometry. Cell-migration was assessed by trans-well-migration chamber-system. RESULTS: AZD5069 exerted negligible effects on cell proliferation or viability. AZD5069 significantly reduced CXCR2, (but not CXCL8) mRNAs in all cell types. CXCR2 was reduced on the membrane of some TC cell lines. A significant reduction of the CXCL8 secretion was found in TPC-1 cells (basal-secretion) and NHT (TNFα-induced secretion). AZD5069 significantly reduced basal and CXCL8-induced migration in NHT and different TC cells. CONCLUSIONS: Our findings confirm the involvement of the CXCL8/CXCR2-axis in promoting pro-tumorigenic effects in TC cells, further demonstrating its immunotherapeutic significance in human cancer.

Myeloid-Derived Suppressor Cells: Therapeutic Target for Gastrointestinal Cancers.

Gastrointestinal cancers represent one of the more challenging cancers to treat. Current strategies to cure and control gastrointestinal (GI) cancers like surgery, radiation, chemotherapy, and immunotherapy have met with limited success, and research has turned towards further characterizing the tumor microenvironment to develop novel therapeutics. Myeloid-derived suppressor cells (MDSCs) have emerged as crucial drivers of pathogenesis and progression within the tumor microenvironment in GI malignancies. Many MDSCs clinical targets have been defined in preclinical models, that potentially play an integral role in blocking recruitment and expansion, promoting MDSC differentiation into mature myeloid cells, depleting existing MDSCs, altering MDSC metabolic pathways, and directly inhibiting MDSC function. This review article analyzes the role of MDSCs in GI cancers as viable therapeutic targets for gastrointestinal malignancies and reviews the existing clinical trial landscape of recently completed and ongoing clinical studies testing novel therapeutics in GI cancers.

AESIS-1, a Rheumatoid Arthritis Therapeutic Peptide, Accelerates Wound Healing by Promoting Fibroblast Migration in a CXCR2-Dependent Manner.

In patients with autoimmune disorders such as rheumatoid arthritis (RA), delayed wound healing is often observed. Timely and effective wound healing is a crucial determinant of a patient's quality of life, and novel materials for skin wound repair, such as bioactive peptides, are continuously being studied and developed. One such bioactive peptide, AESIS-1, has been studied for its well-established anti-rheumatoid arthritis properties. In this study, we attempted to use the anti-RA material AESIS-1 as a therapeutic wound-healing agent based on disease-modifying antirheumatic drugs (DMARDs), which can help restore prompt wound healing. The efficacy of AESIS-1 in wound healing was assessed using a full-thickness excision model in diabetic mice; this is a well-established model for studying chronic wound repair. Initial observations revealed that mice treated with AESIS-1 exhibited significantly advanced wound repair compared with the control group. In vitro studies revealed that AESIS-1 increased the migration activity of human dermal fibroblasts (HDFs) without affecting proliferative activity. Moreover, increased HDF cell migration is mediated by upregulating chemokine receptor expression, such as that of CXC chemokine receptor 2 (CXCR2). The upregulation of CXCR2 through AESIS-1 treatment enhanced the chemotactic reactivity to CXCR2 ligands, including CXC motif ligand 8 (CXCL8). AESIS-1 directly activates the ERK and p38 mitogen-activated protein kinase (MAPK) signaling cascades, which regulate the migration and expression of CXCR2 in fibroblasts. Our results suggest that the AESIS-1 peptide is a strong wound-healing substance that increases the movement of fibroblasts and the expression of CXCR2 by turning on the ERK and p38 MAPK signaling cascades.