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.

Is it possible to treat melanoma by intercepting the CXCR4/CXCL12 pathway?

Melanoma is a particularly aggressive type of skin cancer that can spread to distant organs, resulting in poor patient outcomes. C-X-C motif chemokine ligand 12 (CXCL12) interacts to the C-X-C chemokine receptor type 4 (CXCR4). This connection between CXCR4 and its companion ligand CXCL12 is important in melanoma metastasis and progression, encouraging cell proliferation, invasion, and survival via downstream signaling pathways. Furthermore, CXCR4 is implicated in the interaction between melanoma cells and the tumor microenvironment, which promotes malignant cell migration and immune evasion. Given the importance of the CXCR4/CXCL12 axis in melanoma, addressing this axis has the potential to prevent metastasis and improve patient outcomes. We present an overview of the CXCR4/CXCL12 axis in cancer progression and explain its role in the melanoma microenvironment in this paper. Furthermore, we investigate CXCR4's predictive usefulness as a possible biomarker for monitoring melanoma progression. Finally, we discuss the most recent research and clinical trials on CXCR4 inhibitors, emphasizing their efficacy and limits. We hope to improve the quality of life for melanoma patients by better understanding the role of CXCR4 and investigating novel therapeutic options.

In vitro effects and mathematical modelling of CTCE-9908 (a chemokine receptor 4 antagonist) on melanoma cell survival

CTCE-9908, a CXC chemokine receptor 4 (CXCR4) antagonist, prevents CXCR4 phosphorylation and inhibits the interaction with chemokine ligand 12 (CXCL12) and downstream signalling pathways associated with metastasis. This study evaluated the in vitro effects of CTCE-9908 on B16 F10 melanoma cells with the use of mathematical modelling. Crystal violet staining was used to construct a mathematical model of CTCE-9908 B16 F10 (melanoma) and RAW 264.7 (non-cancerous macrophage) cell lines on cell viability to predict the half-maximal inhibitory concentration (IC50). Morphological changes were assessed using transmission electron microscopy. Flow cytometry was used to assess changes in cell cycle distribution, apoptosis via caspase-3, cell survival via extracellular signal-regulated kinase1/2 activation, CXCR4 activation and CXCL12 expression. Mathematical modelling predicted IC50 values from 0 to 100 h. At IC50, similar cytotoxicity between the two cell lines and ultrastructural morphological changes indicative of cell death were observed. At a concentration 10 times lower than IC50, CTCE-9908 induced inhibition of cell survival (p = 0.0133) in B16 F10 cells but did not affect caspase-3 or cell cycle distribution in either cell line. This study predicts CTCE-9908 IC50 values at various time points using mathematical modelling, revealing cytotoxicity in melanoma and non-cancerous cells. CTCE-9908 significantly inhibited melanoma cell survival at a concentration 10 times lower than the IC50 in B16 F10 cells but not RAW 264.7 cells. However, CTCE-9908 did not affect CXCR4 phosphorylation, apoptosis,\ or cell cycle distribution in either cell line.

Tertiary lymphoid structures as a potential prognostic biomarker for combined hepatocellular-cholangiocarcinoma

BACKGROUND

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA), as a rare primary hepatic tumor, is challenging to accurately assess in terms of the clinical outcomes and prognostic risk factors in patients. This study aimed to clarify the function of tertiary lymphoid structure (TLS) status in predicting the outcome of cHCC-CCA and to preliminarily explore the possible mechanism of TLS formation.

METHODS

The TLSs, with different spatial distributions and densities, of 137 cHCC-CCA were quantified, and their association with prognosis was assessed by Cox regression and Kaplan-Meier analyses. We further validated TLS possible efficacy in predicting immunotherapy responsiveness in two cHCC-CCA case reports. TLS composition and its relationship to CXCL12 expression were analysed by fluorescent multiplex immunohistochemistry.

RESULTS

A high intratumoural TLS score was correlated with prolonged survival, whereas a high TLS density in adjacent tissue indicated a worse prognosis in cHCC-CCA. Mature TLSs were related to favorable outcomes and showed more CD8 + T cells infiltrating tumor tissues. We further divided the cHCC-CCA patients into four immune grades by combining the peri-TLS and intra-TLS, and these grades were an independent prognostic factor. In addition, our reported cases suggested a potential value of TLS in predicting immunotherapy response in cHCC-CCA patients. Our findings suggested that CXCL12 expression in cHCC-CCA tissue was significantly correlated with TLS presence.

CONCLUSION

The spatial distribution and density of TLSs revealing the characteristics of the cHCC-CCA immune microenvironment, significantly correlated with prognosis and provided a potential immunotherapy response biomarker for cHCC-CCA.

Establishment of Early Blood Perfusion Promotes CXCL12 Expression and Recruits Monocytes/Macrophages in Damaged Adipose Tissue in Mice Model

BACKGROUND

Blood perfusion in the recipient site is important for adipose tissue repair after fat grafting. It delivers host-derived macrophages derived from monocytes in bone marrow to initiate inflammatory reactions and regenerative responses. According to the ability of CXCL12, a stromal cell-derived factor, to recruit monocytes/macrophages, we studied its effect on adipose tissue repair and regeneration under ischemic and normal conditions.

METHODS

Each inguinal fat pad was crushed for 30 seconds with a clamp in mice (n = 35). The left inguinal vessels were divided and cut off (ischemic group), while the right inguinal vessels were kept patent (control group). Seven animals were sacrificed at 1, 3, 7, 14, and 30 days after surgery, and macrophages (Mac2 and CD206) and adipocytes (perilipin) were assessed. Levels of inflammatory factors (interleukin (IL)-1β, IL-6, and tumor necrosis factor-α) and CXCL12 were measured by quantitative PCR.

RESULTS

The number of macrophages was higher in the control group than in the ischemic group at day 3 (10.33 ± 2.40 vs. 1.33 ± 0.33, p = 0.021). The percentage of M2 macrophages was higher in the control group than in the ischemic group at day 7 (p<0.05). The levels of inflammatory factors and CXCL12 were higher in the control group than in the ischemic group at the early stage (p = 0.038).

CONCLUSIONS

Established blood perfusion leads to up-regulation of CXCL12 during adipose tissue repair and regeneration, which may increase recruitment of monocytes to damaged adipose tissue. These findings increase understanding of the cellular events involved in fat graft survival after grafting.

NO LEVEL ASSIGNED

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The effect of CXCL12 on survival outcomes of patients with viral hepatitis-associated hepatocellular carcinoma after hepatectomy

Background

The CXCL12-CXCR4/CXCR7 axis is garnering growing attention. But the comprehension of its function in the progression of HCC remains controversial. The purpose of this study was to investigate the effects of CXCL12 and its receptor on the prognosis of patients with viral hepatitis-associated HCC after hepatectomy.

Methods

A total of 86 patients had been enrolled who had undergone hepatectomy for HCC and followed up to July 31, 2019, and their clinicopathological and follow-up data were recorded. Tumor and peritumoral tissues were obtained to detect the expression of CXCL12, CXCR4, and CXCR7 using immunohistochemistry. Real-time polymerase chain reaction was utilized to detect hepatitis B or C virus loads, while survival analysis was performed using the Kaplan-Meier method. Furthermore, the Cox proportional hazards regression model was employed to analyze the factors affecting the prognosis.

Results

The results revealed that the CXCL12, CXCR4, and CXCR7 expression in tumor tissues was lower than in the corresponding non-tumor tissues in 20.93 %, 22.09 %, and 23.26 % of the patients, respectively, and that only CXCL12 was found to be related to the extrahepatic invasion of HCC. The survival analysis and Cox regression showed that only CXCL12 was associated with the postoperative survival of patients with HCC, and that it was an independent prognostic risk factor in the CXCL12-CXCR4/CXCR7 axis. The CXCL12low group represented shorter progression-free survival and lower overall survival rates. However, the subgroup analysis displayed that the survival difference associated with CXCL12 was only manifested in patients with higher expression of CXCR4 or CXCR7 in HCC, as compared to the surrounding tissues.

Conclusions

Our findings suggest that, when assessing the prognostic significance of CXCL12 in HCC, it is essential to consider the expression level of its receptor. Nevertheless, CXCL12 can potentially serve as a promising prognostic marker for HCC.

Preventing CXCL12 elevation helps to reduce acute exacerbation of COPD in individuals co-existing type-2 diabetes: A bioinformatics and clinical pharmacology study

AIMS

To investigate the immunology shared mechanisms underlying chronic obstructive pulmonary disease (COPD) and type 2 diabetes mellitus (T2DM) and examine the impact of anti-diabetic drugs on acute exacerbation of COPD (AECOPD).

METHODS

We analyzed GSE76925, GSE76894, GSE37768, and GSE25724 to identify differentially expressed genes. Hub-genes were identified through protein-protein interaction network analysis and evaluated by the receiver operating characteristic curve. CXCL12 emerged as a robust biomarker, and its correlation with lung function and CD8+ T cells were further quantified and validated. The activated signaling pathways were inferred through Gene set enrichment analysis (GSEA). The retrospective clinical analysis was executed to identify the influence of dipeptidyl peptidase-4 inhibitors (DPP-4i) on CXCL12 and evaluate the drug's efficacy in AECOPD.

RESULTS

The significant up-regulation of CXCL12 expression in patients with two diseases were revealed. CXCL12 exhibited a negative correlation with pulmonary function (r = -0.551, p < 0.05). Consistent with analysis in GSE76925 and GSE76894, the positive correlation between the proportion of CD8+ T cells was demonstrated(r=0.469, p<0.05). GSEA identified "cytokines interaction" as an activated signaling pathway, and the clinical study revealed the correlation between CXCL12 and IL-6 (r=0.668, p<0.05). In patients with COPD and T2DM, DDP-4i treatment exhibited significantly higher serum CXCL12, compared to GLP-1RA. Analysis of 187 COPD patients with T2DM indicated that the DPP-4i group had a higher frequency of AECOPD compared to the GLP-1RA group (OR 1.287, 95%CI [1.018-2.136]).

CONCLUSIONS

CXCL12 may represent a therapeutic target for COPD and T2DM. GLP-1RA treatment may be associated with lower CXCL12 levels and a lower risk of AECOPD compared to DPP-4i treatment.

CLINICAL TRIAL REGISTRATION

China Clinical Trial Registration Center（ChiCTR2200055611）.

Migrasomes from adipose derived stem cells enrich CXCL12 to recruit stem cells via CXCR4/RhoA for a positive feedback loop mediating soft tissue regeneration

BACKGROUND

Adipose-derived stem cells (ASCs) represent the most advantageous choice for soft tissue regeneration. Studies proved the recruitment of ASCs post tissue injury was mediated by chemokine CXCL12, but the mechanism by which CXCL12 is generated after tissue injury remains unclear. Migrasomes are newly discovered membrane-bound organelles that could deliver CXCL12 spatially and temporally in vivo. In this study, we sought to investigate whether migrasomes participate ASC-mediated tissue regeneration.

METHODS

Discrepant and asymmetrical soft tissue regeneration mice model were established, in which HE staining, immunofluorescent staining, western blot and qPCR were conducted to confirm the role of CXCL12 and migrasomes in ASC-mediated tissue regeneration. Characterization of ASC-derived migrasomes were carried out by confocal microscopy, scanning electron microscopy, transmission electron microscopy as well as western blot analysis. The function and mechanism of migrasomes were further testified by assisting tissue regeneration with isolated migrasomes in vivo and by in vitro transwell combined with co-culture system.

RESULTS

Here, we show for the first time that migrasomes participate in soft tissue regeneration. ASCs generate migrasomes enriched with CXCL12 to mediate tissue regeneration. Migrasomes from ASCs could promote stem cells migration by activating CXCR4/RhoA signaling in vivo and in vitro. Chemoattracted ASCs facilitate regeneration, as demonstrated by the upregulation of an adipogenesis-associated protein. This positive feed-back-loop creates a favorable microenvironment for soft tissue regeneration. Thus, migrasomes represent a new therapeutic target for ASC-mediated tissue regeneration.

CONCLUSIONS

Our findings reveal a previously unknown function of ASCs in mediating tissue regeneration by generating migrasomes. The ASC-derived migrasomes can restore tissue regeneration by recruiting stem cells, which highlighting the potential application of ASC-derived migrasomes in regenerative medicine.

Overexpression of HSP27 accelerates stress-induced gastric ulcer healing via the CXCL12/CXCR4 axis

Chronic stress often triggers gastrointestinal complications, including gastric injury and ulcers. Understanding the role of heat shock protein 27 (HSP27) in stress-induced gastric ulcers could unveil novel therapeutic targets. Here, we established a stress-induced gastric ulcer rat model using water immersion restraint stress and administered adenovirus-packaged HSP27 overexpression vector. Gastric ulcer severity was scored, and mucosal changes were assessed. Gastric epithelial and endothelial cells were treated with lipopolysaccharide and transfected with HSP27 overexpression vectors to evaluate cell viability, migration and angiogenesis. Expression levels of HSP27, C-X-C motif chemokine ligand 12 (CXCL12) and C-X-C motif chemokine receptor 4 (CXCR4) were measured in tissues and cells. HSP27 expression was initially low during stress-induced gastric ulceration but increased during ulcer healing. HSP27 overexpression accelerated ulcer healing in rats, promoting gastric epithelial cell proliferation and migration and gastric endothelial cell angiogenesis through the CXCL12/CXCR4 axis. Inhibitor IT1t reversed the effects of HSP27 overexpression on cell proliferation, migration and angiogenesis. In summary, HSP27 overexpression facilitated ulcer healing, which was partially mediated by the CXCL12/CXCR4 axis.

Targeting the CXCL12/CXCR4 pathway to reduce radiation treatment side effects

High precision, image-guided radiotherapy (RT) has increased the therapeutic ratio, enabling higher tumor and lower normal tissue doses, leading to improved patient outcomes. Nevertheless, some patients remain at risk of developing serious side effects.In many clinical situations, the radiation tolerance of normal tissues close to the target volume limits the dose that can safely be delivered and thus the potential for tumor control and cure. This is particularly so in patients being re-treated for tumor progression or a second primary tumor within a previous irradiated volume, scenarios that are becoming more frequent in clinical practice.Various normal tissue 'radioprotective' drugs with the potential to reduce side effects have been studied previously. Unfortunately, most have failed to impact clinical practice because of lack of therapeutic efficacy, concern about concurrent tumor protection or excessive drug-related toxicity. This review highlights the evidence indicating that targeting the CXCL12/CXCR4 pathway can mitigate acute and late RT-induced injury and reduce treatment side effects in a manner that overcomes these previous translational challenges. Pre-clinical studies involving a broad range of normal tissues commonly affected in clinical practice, including skin, lung, the gastrointestinal tract and brain, have shown that CXCL12 signalling is upregulated by RT and attracts CXCR4-expressing inflammatory cells that exacerbate acute tissue injury and late fibrosis. These studies also provide convincing evidence that inhibition of CXCL12/CXCR4 signalling during or after RT can reduce or prevent RT side effects, warranting further evaluation in clinical studies. Greater dialogue with the pharmaceutical industry is needed to prioritize the development and availability of CXCL12/CXCR4 inhibitors for future RT studies.

SAP deletion promotes malignant insulinoma progression by inducing CXCL12 secretion from CAFs via the CXCR4/p38/ERK signalling pathway

Malignant insulinoma is an extremely rare type of functioning pancreatic neuroendocrine tumour with a high degree of malignancy and a high incidence of metastasis. However, it is still unclear how malignant insulinomas develop and metastasize. Serum amyloid P component (SAP), a member of the pentraxin protein family, is an acute-phase protein secreted by liver cells. The role of SAP in insulinoma and the related mechanism are still unknown. To determine the effect of SAP on insulinoma, we crossed Rip1-Tag2 mice, which spontaneously develop insulinoma, and SAP knockout (KO) mice to generate Rip1-Tag2;SAP-/- mice. We found that SAP deletion significantly promoted the growth, invasion and metastasis of malignant insulinoma through C-X-C motif chemokine ligand 12 (CXCL12) secreted by cancer-associated fibroblasts (CAFs). Further study showed that SAP deletion promoted CXCL12 secretion by CAFs through the CXCR4/p38/ERK signalling pathway. These findings reveal a novel role and mechanism of SAP in malignant insulinoma and provide direct evidence that SAP may be a therapeutic agent for this disease.

CXCR4/CXCL12 axis: "old" pathway as "novel" target for anti-inflammatory drug discovery

Inflammation is the body's defense response to exogenous or endogenous stimuli, involving complex regulatory mechanisms. Discovering anti-inflammatory drugs with both effectiveness and long-term use safety is still the direction of researchers' efforts. The inflammatory pathway was initially identified to be involved in tumor metastasis and HIV infection. However, research in recent years has proved that the CXC chemokine receptor type 4 (CXCR4)/CXC motif chemokine ligand 12 (CXCL12) axis plays a critical role in the upstream of the inflammatory pathway due to its chemotaxis to inflammatory cells. Blocking the chemotaxis of inflammatory cells by CXCL12 at the inflammatory site may block and alleviate the inflammatory response. Therefore, developing CXCR4 antagonists has become a novel strategy for anti-inflammatory therapy. This review aimed to systematically summarize and analyze the mechanisms of action of the CXCR4/CXCL12 axis in more than 20 inflammatory diseases, highlighting its crucial role in inflammation. Additionally, the anti-inflammatory activities of CXCR4 antagonists were discussed. The findings might help generate new perspectives for developing anti-inflammatory drugs targeting the CXCR4/CXCL12 axis.

Presence of immunoglobulin E-expressing antibody-secreting cells in the dermis close to bullous pemphigoid lesions

Antibody-secreting cells (ASCs) produce immunoglobulin (Ig) G and IgE autoantibodies in secondary lymphoid organs. Evidence also suggests their existence in the skin in various chronic inflammatory conditions, and in association with CXCL12 and CXCL13, they regulate the recruitment/survival of ASCs and germinal center formation to generate ASCs, respectively. However, the presence of IgG and IgE in bullous pemphigoid (BP) lesions needs to be addressed. Here, we aimed to analyse BP skin for the presence of IgG and IgE and the factors contributing to their generation, recruitment, and persistence. Skin samples from 30 patients with BP were stained to identify ASCs and the immunoglobulin type they expressed. The presence of tertiary lymphoid organ (TLO) elements, which generate ASCs in non-lymphoid tissues, and the chemokines CXCL12 and CXCL13, which regulate the migration/persistence of ASCs in lymphoid tissues and formation of TLOs, respectively, were evaluated in BP skin. BP skin harboured ASCs expressing the two types of antibodies IgG and IgE. ASCs were found in high-grade cellular aggregates containing TLO elements: T cells, B cells, CXCL12+ cells, CXCL13+ cells and high endothelial venules. IgG+ ASCs were detected among these aggregates, whereas IgE+ ASCs were dispersed throughout the dermis. CXCL12+ fibroblast-like cells were located close to ASCs. The inflammatory microenvironment of BP lesions may contribute to the antibody load characteristic of the skin of patients with BP by providing a site for the presence of ASCs. CXCL13 and CXCL12 expression may contribute to the generation and recruitment/survival of ASCs, respectively.

Evaluating serum CXCL12, sCD22, Lp-PLA2 levels and ratios as biomarkers for diagnosis of Alzheimer's disease

BACKGROUND

Grasping the underlying mechanisms of Alzheimer's disease (AD) is still a work in progress, and existing diagnostic techniques encounter various obstacles. Therefore, the discovery of dependable biomarkers is essential for early detection, tracking the disease's advancement, and steering treatment strategies.

AIM

To explore the diagnostic potential of serum CXCL12, sCD22, Lp-PLA2, and their ratios in AD, aiming to enhance early detection and inform targeted treatment strategies.

METHODS

The study was conducted in Dongying people's Hospital from January 2021 to December 2022. Participants included 60 AD patients (AD group) and 60 healthy people (control group). Using a prospective case-control design, the levels of CXCL12, sCD22 and Lp-PLA2 and their ratios were detected by enzyme-linked immunosorbent assay kit in the diagnosis of AD. The differences between the two groups were analyzed by statistical methods, and the corresponding ratio was constructed to improve the specificity and sensitivity of diagnosis.

RESULTS

Serum CXCL12 levels were higher in the AD group (47.2 ± 8.5 ng/mL) than the control group (32.8 ± 5.7 ng/mL, P < 0.001), while sCD22 levels were lower (14.3 ± 2.1 ng/mL vs 18.9 ± 3.4 ng/mL, P < 0.01). Lp-PLA2 levels were also higher in the AD group (112.5 ± 20.6 ng/mL vs 89.7 ± 15.2 ng/mL, P < 0.05). Significant differences were noted in CXCL12/sCD22 (3.3 vs 1.7, P < 0.001) and Lp-PLA2/sCD22 ratios (8.0 vs 5.2, P < 0.05) between the groups. Receiver operating characteristic analysis confirmed high sensitivity and specificity of these markers and their ratios in distinguishing AD, with area under the curves ranging from 0.568 to 0.787.

CONCLUSION

Serum CXCL12 and Lp-PLA2 levels were significantly increased, while sCD22 were significantly decreased, as well as increases in the ratios of CXCL12/sCD22 and Lp-PLA2/sCD22, are closely related to the onset of AD. These biomarkers and their ratios can be used as potential diagnostic indicators for AD, providing an important clinical reference for early intervention and treatment.

Activation of the CXCR4 Receptor by Chemokine CXCL12 Increases the Excitability of Neurons in the Rat Central Amygdala

Primarily regarded as immune proteins, chemokines are emerging as a family of molecules serving neuromodulatory functions in the developing and adult brain. Among them, CXCL12 is constitutively and widely expressed in the CNS, where it was shown to act on cellular, synaptic, network, and behavioral levels. Its receptor, CXCR4, is abundant in the amygdala, a brain structure involved in pathophysiology of anxiety disorders. Dysregulation of CXCL12/CXCR4 signaling has been implicated in anxiety-related behaviors. Here we demonstrate that exogenous CXCL12 at 2 nM but not at 5 nM increased neuronal excitability in the lateral division of the rat central amygdala (CeL) which was evident in the Late-Firing but not Regular-Spiking neurons. These effects were blocked by AMD3100, a CXCR4 antagonist. Moreover, CXCL12 increased the excitability of the neurons of the basolateral amygdala (BLA) that is known to project to the CeL. However, CXCL12 increased neither the spontaneous excitatory nor spontaneous inhibitory synaptic transmission in the CeL. In summary, the data reveal specific activation of Late-Firing CeL cells along with BLA neurons by CXCL12 and suggest that this chemokine may alter information processing by the amygdala that likely contributes to anxiety and fear conditioning.

SPI1-mediated CXCL12 expression in bladder cancer affects the recruitment of tumor-associated macrophages

Bladder cancer (BC) originates principally from the epithelial compartment of the bladder. The immune system and its diverse players, chemokines, in particular, have been related to the responses against BC. The goal of the study here was to examine if C-X-C motif chemokine 12 (CXCL12) in BC cells could manipulate protumorigenic properties of tumor-associated macrophages (TAMs) which affects anticancer immunity supporting tumor development in the tumor microenvironment. CXCL12 was found to be overexpressed in BC and predicted poor survival. CXCL12 in BC was associated with multiple immune cell infiltrations, with TAM infiltration playing a key role. CXCL12 elevated chemotaxis of TAMs. CXCL12 downregulation inhibited cellular activity and TAM and suppressed the ability of TAMs to secrete inflammatory factors and MMP9. Furthermore, chromatin immunoprecipitation analysis revealed that SPI1 was localized to the CXCL12 promoter in BC cells, suggesting that CXCL12 serves a direct target of SPI1, which was consistent with the fact that SPI1 reversed the repressive effects of si-CXCL12 on BC cell activity and TAM recruitment in vitro and in vivo. Collectively, these findings suggest that SPI1 is involved in modulating TAM recruitment, representing a new mechanism through which it may influence tumor growth. This may be partly mediated by regulating CXCL12 expression.

Tumor-associated macrophages promoting PD-L1 expression in infiltrating B cells through the CXCL12/CXCR4 axis in human hepatocellular carcinoma

The inflammation-related tumor microenvironment (TME) is one of the major driving forces of hepatocarcinogenesis. We aimed to investigate cell-to-cell communication among Hepatocellular Carcinoma (HCC) through re-analyzing HCC single-cell RNA-seq data, and to confirm such cellular interaction through in vitro and in vivo study. We found a subset of Regulatory B cells with PD-L1 expression (PD-L1+ Bregs), mainly located in adjacent HCC tissues. In co-localization with PD-L1+ Bregs, a subset of Tumor Associated Macrophages with high expression of CXCL12 (CXCL12+ TAMs) was also mainly located in adjacent HCC tissues. Moreover, CXCL12+ TAMs can be stimulated in vitro using an HCC conditional medium. Using CellChat analysis and Multiplex Immunohistochemistry staining (mIHC), CXCL12+ TAMs were found to be first recruited by Cancer-Associated Fibroblasts (CAFs) through a CD74/macrophage migration inhibitory factor (MIF) pattern, and further differentiated into TGF-β-enriched tissues. Furthermore, CXCL12+ TAMs recruited PD-L1+ Bregs via the CXCL12/CXCR4 axis, and CXCR4 expression was significantly positively correlated to PD-L1 expression in PD-L1+ Bregs. At last, we confirmed the communications among CAFs, Macrophages and B cells and their tumor-promoting effects by using an orthotopic mouse model of HCC. Immunosuppressive HCC TME involving cell-to-cell communications comprised MIF-secreting CAFs, CXCL12-secreting TAMs, and PD-L1-producing Bregs, and their regulation could be promising therapeutic targets in future immunotherapy for human HCC.

Deciphering the differential impact of thrombopoietin/MPL signaling on hematopoietic stem/progenitor cell function in bone marrow and spleen

Thrombopoietin (TPO) and its receptor MPL play crucial roles in hematopoietic stem cell (HSC) function and platelet production. However, the precise effects of TPO/MPL signaling on HSC regulation in different hematopoietic niches remain unclear. Here, we investigated the effects of TPO/MPL ablation on marrow and splenic hematopoiesis in TPO-/- and MPL-/- mice during aging. Despite severe thrombocytopenia, TPO-/- and MPL-/- mice did not develop marrow failure during a 2-year follow-up. Marrow and splenic HSCs exhibited different responses to TPO/MPL ablation and exogenous TPO treatment. Splenic niche cells compensated for marrow HSC loss in TPO-/- and MPL-/- mice by upregulating CXCL12 levels. These findings provide new insights into the complex regulation of HSCs by TPO/MPL and reveal a previously unknown link between TPO and CXCL12, two key growth factors for HSC maintenance. Understanding the distinct regulatory mechanisms between marrow and spleen hematopoiesis will help to develop novel therapeutic approaches for hematopoietic disorders.

FOXC1 Promotes Osteoblastic Differentiation of Bone Marrow Mesenchymal Stem Cells via the Dnmt3b/CXCL12 Axis

Bone defects have remained a clinical problem in current orthopedics. Bone marrow mesenchymal stem cells (BM-MSCs) with multi-directional differentiation ability have become a research hotspot for repairing bone defects. In vitro and in vivo models were constructed, respectively. Alkaline phosphatase (ALP) staining and alizarin red staining were performed to detect osteogenic differentiation ability. Western blotting (WB) was used to detect the expression of osteogenic differentiation-related proteins. Serum inflammatory cytokine levels were detected by ELISA. Fracture recovery was evaluated by HE staining. The binding relationship between FOXC1 and Dnmt3b was verified by dual-luciferase reporter assay. The relationship between Dnmt3b and CXCL12 was explored by MSP and ChIP assays. FOXC1 overexpression promoted calcium nodule formation, upregulated osteogenic differentiation-related protein expression, promoted osteogenic differentiation, and decreased inflammatory factor levels in BM-MSCs, and promoted callus formation, upregulated osteogenic differentiation-related protein expression, and downregulated CXCL12 expression in the mouse model. Furthermore, FOXC1 targeted Dnmt3b, with Dnmt3b knockdown decreasing calcium nodule formation and downregulating osteogenic differentiation-related protein expression. Additionally, inhibiting Dnmt3b expression upregulated CXCL12 protein expression and inhibited CXCL12 methylation. Dnmt3b could be binded to CXCL12. CXCL12 overexpression attenuated the effects of FOXC1 overexpression and inhibited BM-MSCs osteogenic differentiation. This study confirmed that the FOXC1-mediated regulation of the Dnmt3b/CXCL12 axis had positive effects on the osteogenic differentiation of BM-MSCs.

CXCL12-CXCR4 mediates CD57+ CD8+ T cell responses in the progression of type 1 diabetes

CD57+ CD8+ T cells, also referred as effector memory cells, are implicated in various conditions including tumor immunity, virus immunity, and most recently with autoimmunity. However, their roles in the progression and remission of T1D are still unclear. Here, we noted an increase in peripheral CD57+ CD8+ T cells in a T1D patient harboring an activator of transcription 3 (STAT3) mutation. Our in-depth study on the role of CD57+ CD8+ T cells within a T1D patient cohort revealed that these cells undergo significant compositional shifts during the disease's progression. Longitudinal cohort data suggested that CD57+ CD8+ T cell prevalence may be a harbinger of β-cell function decline in T1D patients. Characterized by robust cytotoxic activity, heightened production of pro-inflammatory cytokines, and increased intracellular glucose uptake, these cells may be key players in the pathophysiology of T1D. Moreover, in vitro assays showed that the CXCL12-CXCR4 axis promotes the expansion and function of CD57+ CD8+ T cells via Erk1/2 signaling. Notably, the changes of serum CXCL12 concentrations were also found in individuals during the peri-remission phase of T1D. Furthermore, treatment with the CXCR4 antagonist LY2510924 reduced the immunological infiltration of CD57+ CD8+ T cells and mitigated hyperglycemia in a STZ-induced T1D mouse model. Taken together, our work has uncovered a novel role of the CXCL12-CXCR4 axis in driving CD57+ CD8+ T cells responses in T1D, and presented a promising therapeutic strategy for delaying the onset and progression of diabetes.

An emerging paradigm of CXCL12 involvement in the metastatic cascade

The chemokine CXCL12, also known as stromal cell-derived factor 1 (SDF1), has emerged as a pivotal regulator in the intricate molecular networks driving cancer progression. As an influential factor in the tumor microenvironment, CXCL12 plays a multifaceted role that spans beyond its traditional role as a chemokine inducing invasion and metastasis. Indeed, CXCL12 has been assigned functions related to epithelial-to-mesenchymal transition, cancer cell stemness, angiogenesis, and immunosuppression, all of which are currently viewed as specialized biological programs contributing to the "metastatic cascade" among other cancer hallmarks. Its interaction with its cognate receptor, CXCR4, initiates a cascade of events that not only shapes the metastatic potential of tumor cells but also defines the niches within the secondary organs that support metastatic colonization. Given the profound implications of CXCL12 in the metastatic cascade, understanding its mechanistic underpinnings is of paramount importance for the targeted elimination of rate-limiting steps in the metastatic process. This review aims to provide a comprehensive overview of the current knowledge surrounding the role of CXCL12 in cancer metastasis, especially its molecular interactions rationalizing its potential as a therapeutic target.

The chemokines CCL5 and CXCL12 exhibit high-affinity binding to N-terminal peptides of the non-cognate receptors CXCR4 and CCR5, respectively

CC and CXC chemokines are distinct chemokine subfamilies. CC chemokines usually do not bind CXC-chemokine receptors and vice versa. CCR5 and CXCR4 receptors are activated by CCL5 and CXCL12 chemokines, respectively, and are also used as HIV-1 coreceptors. CCL5 contains one conserved binding site for a sulfated tyrosine residue, whereas CXCL12 is unique in having two additional sites for sulfated/nonsulfated tyrosine residues. In this study, N-terminal (Nt) CXCR4 peptides were found to bind CCL5 with somewhat higher affinities in comparison to those of short Nt-CCR5(8-20) peptides with the same number of sulfated tyrosine residues. Similarly, a long Nt-CCR5(1-27)(s Y3,s Y10,s Y14) peptide cross reacts with CXCL12 and with lower KD in comparison to its binding to CCL5. Intermolecular nuclear overhauser effect (NOE) measurements were used to decipher the mechanism of the chemokine/Nt-receptor peptide binding. The Nt-CXCR4 peptides interact with the conserved CCL5 tyrosine sulfate-binding site by an allovalency mechanism like that observed for CCL5 binding of Nt-CCR5 peptides. Nt-CCR5 peptides bind CXCL12 in multiple modes analogous to their binding to HIV-1 gp120 and interact with all three tyrosine/sulfated tyrosine-binding pockets of CXCL12. We suggest that the chemokine-receptors Nt-segments bind promiscuously to cognate and non-cognate chemokines and in a mechanism that is dependent on the number of binding pockets for tyrosine residues found on the chemokine. In conclusion, common features shared among the chemokine-receptors' Nt-segments such as multiple tyrosine residues that are potentially sulfated, and a large number of negatively charged residues are the reason of the cross binding observed in this study.

CXCL12 Neutralizing Antibody Promotes Hair Growth in Androgenic Alopecia and Alopecia Areata

We had previously investigated the expression and functional role of C-X-C Motif Chemokine Ligand 12 (CXCL12) during the hair cycle progression. CXCL12 was highly expressed in stromal cells such as dermal fibroblasts (DFs) and inhibition of CXCL12 increased hair growth. Therefore, we further investigated whether a CXCL12 neutralizing antibody (αCXCL12) is effective for androgenic alopecia (AGA) and alopecia areata (AA) and studied the underlying molecular mechanism for treating these diseases. In the AGA model, CXCL12 is highly expressed in DFs. Subcutaneous (s.c.) injection of αCXCL12 significantly induced hair growth in AGA mice, and treatment with αCXCL12 attenuated the androgen-induced hair damage in hair organ culture. Androgens increased the secretion of CXCL12 from DFs through the androgen receptor (AR). Secreted CXCL12 from DFs increased the expression of the AR and C-X-C Motif Chemokine Receptor 4 (CXCR4) in dermal papilla cells (DPCs), which induced hair loss in AGA. Likewise, CXCL12 expression is increased in AA mice, while s.c. injection of αCXCL12 significantly inhibited hair loss in AA mice and reduced the number of CD8+, MHC-I+, and MHC-II+ cells in the skin. In addition, injection of αCXCL12 also prevented the onset of AA and reduced the number of CD8+ cells. Interferon-γ (IFNγ) treatment increased the secretion of CXCL12 from DFs through the signal transducer and activator of transcription 3 (STAT3) pathway, and αCXCL12 treatment protected the hair follicle from IFNγ in hair organ culture. Collectively, these results indicate that CXCL12 is involved in the progression of AGA and AA and antibody therapy for CXCL12 is promising for hair loss treatment.

Aitongping patch could alleviate cancer pain via suppressing microglia activation and modulating the miR-150-5p/CXCL12 signaling

PURPOSE

We aimed to investigate the pharmacological effects and mechanisms of the Aitongping formula for treating cancer pain.

METHODS

We enrolled 60 cancer patients with Numeric Rating Scale above 4 and grouped them randomly as a Control group (N = 30) and a Patch group (N = 30). We also established bone cancer mice models via tumor implantation. And the animal groups were established as a Sham group, a tumor cell implantation (TCI) group, a TCI + Patch group, and a Patch group.

RESULTS

After the validation of successful tumor implantation, we identified candidate miRNAs and genes that were dysregulated in TCI mice and compared their expressions between different mice groups. We also observed the effect of Aitongping patch in vitro in mice primary microglia. The time to disease progression and cancer stability were prolonged by Aitongping patch in cancer patients. And the daily morphine dose was lower, and patients' quality of life was improved in the Patch group. Moreover, Aitongping patch alleviated cancer pain and inhibited microglia activation after the successful implantation of bone tumor in TCI mice. We also observed the dysregulation of miR-150-5p and chemokine CXC motif ligand 12 (CXCL12) mRNA in TCI mice. And CXCL12 was found to be targeted by miR-150-5p. Aitongping patch was found to upregulate miR-150-5p and downregulate CXCL12 in vivo and in vitro.

CONCLUSION

Aitongping patch could alleviate cancer pain via suppressing microglia activation, and the downregulation of miR-150-5p, as well as the upregulation of CXCL12 mRNA and protein, induced by tumor implantation or lipopolysaccharide stimulation, was restored by Aitongping treatment.

CXCL12 promotes the crossing of retinal ganglion cell axons at the optic chiasm

Binocular vision requires the segregation of retinal ganglion cell (RGC) axons extending from the retina into the ipsilateral and contralateral optic tracts. RGC axon segregation occurs at the optic chiasm, which forms at the ventral diencephalon midline. Using expression analyses, retinal explants and genetically modified mice, we demonstrate that CXCL12 (SDF1) is required for axon segregation at the optic chiasm. CXCL12 is expressed by the meninges bordering the optic pathway, and CXCR4 by both ipsilaterally and contralaterally projecting RGCs. CXCL12 or ventral diencephalon meninges potently promoted axon outgrowth from both ipsilaterally and contralaterally projecting RGCs. Further, a higher proportion of axons projected ipsilaterally in mice lacking CXCL12 or its receptor CXCR4 compared with wild-type mice as a result of misrouting of presumptive contralaterally specified RGC axons. Although RGCs also expressed the alternative CXCL12 receptor ACKR3, the optic chiasm developed normally in mice lacking ACKR3. Our data support a model whereby meningeal-derived CXCL12 helps drive axon growth from CXCR4-expressing RGCs towards the diencephalon midline, enabling contralateral axon growth. These findings further our understanding of the molecular and cellular mechanisms controlling optic pathway development.

SP1-Driven FOXM1 Upregulation Induces Dopaminergic Neuron Injury in Parkinson's Disease

The aberrant expression of Forkhead box M1 (FOXM1) has been associated with the pathological processes of Parkinson's disease (PD), but the upstream and downstream regulators remain poorly understood. This study sought to examine the underlying mechanism of FOXM1 in dopaminergic neuron injury in PD. Bioinformatics analysis was conducted to pinpoint the differential expression of FOXM1, which was verified in the nigral tissues of rotenone-lesioned mice and dopaminergic neuron MN9D cells. Interactions among SP1, FOXM1, SNAI2, and CXCL12 were analyzed. To evaluate their effects on dopaminergic neuron injury, the lentiviral vector-mediated manipulation of FOXM1, SP1, and CXCL12 was introduced in rotenone-lesioned mice and MN9D cells. SP1, FOXM1, SNAI2, and CXCL12 abundant expression occurred in rotenone-lesioned mice and MN9D cells. Silencing of FOXM1 delayed the rotenone-induced dopaminergic neuron injury in vitro. Mechanistically, SP1 was an upstream transcription factor of FOXM1 and upregulated FOXM1 expression, leading to increased SNAI2 and CXCL12 expression. In vivo, data confirmed that SP1 promoted dopaminergic neuron injury by activating the FOXM1/SNAI2/CXCL12 axis. Our data indicate that SP1 silencing has neuroprotective effects on dopaminergic neurons, which is dependent upon the inactivated FOXM1/SNAI2/CXCL12 axis.

Diagnostic and prognostic utility of TROP-2, SLP-2, and CXCL12 expression in papillary thyroid carcinoma

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most frequent thyroid malignancy. Histopathological examination is widely accepted as the gold standard test for the diagnosis of PTC. However, the histopathological examination sometimes can't differentiate PTC from other thyroid diseases. Differentiating PTC from other thyroid diseases is essential for a therapeutic approach and prognosis.

OBJECTIVES

The current study was performed to investigate the utility of TROP-2, SPL-2, and CXCL12 mRNA and protein expression in discriminating PTC from other thyroid diseases that mimic PTC.

METHODS

The current study was performed on 75 cases of surgically resected thyroid glands. The cases were distributed in two groups: the PTC group and the non-PTC group. The PTC group consisted of 35 cases (25 patients of the classic PTC variant and 10 patients of the PTC follicular variant). The non-PTC group consisted of 40 cases (10 cases were multinodular goiter, 5 cases were Graves' disease, 5 cases were Hashimoto thyroiditis, 15 patients were follicular adenoma (FA) and 5 cases were follicular carcinoma). TROP-2, SPL-2, and CXCL12 mRNA expression were estimated by qRT-PCR, and protein expression was estimated by immunohistochemistry.

RESULTS

There were upregulated TROP-2, SPL-2, and CXCL12 mRNA and protein expressions in PTC compared to non-PTC (P< 0.001, for each). There was a statistically significant upregulation in the mRNA expression of the three genes among PTC cases with larger tumor sizes (P< 0.001, for each), those with tumor stages III and IV (P= 0.008, 0.002 and < 0.001 respectively), and those with LN metastasis (P< 0.001, for each). Moreover, there was a statistically significant upregulation in CXCL-12 gene expression among PTC cases with extra-thyroid extension (P< 0.001).

CONCLUSION

mRNA expression of TROP-2, SPL-2, and CXCL12 among PTC cases increased in larger tumor size, tumor stages III and IV, and LN metastasis. Moreover, there was an increase in CXCL-12 gene expression among PTC cases with extra-thyroid extension. Thus, TROP-2, SPL-2, and CXCL12 expressions could be possible diagnostic and prognostic markers in PTC.

siRNA lipid nanoparticles for CXCL12 silencing modulate brain immune response during Zika infection

CXCL12 is a key chemokine implicated in neuroinflammation, particularly during Zika virus (ZIKV) infection. Specifically, CXCL12 is upregulated in circulating cells of ZIKV infected patients. Here, we developed a lipid nanoparticle (LNP) to deliver siRNA in vivo to assess the impact of CXCL12 silencing in the context of ZIKV infection. The biodistribution of the LNP was assessed in vivo after intravenous injection using fluorescently tagged siRNA. Next, we investigated the ability of the developed LNP to silence CXCL12 in vivo and assessed the resulting effects in a murine model of ZIKV infection. The LNP encapsulating siRNA significantly inhibited CXCL12 levels in the spleen and induced microglial activation in the brain during ZIKV infection. This activation was evidenced by the enhanced expression of iNOS, TNF-α, and CD206 within microglial cells. Moreover, T cell subsets exhibited reduced secretion of IFN-ɣ and IL-17 following LNP treatment. Despite no observable alteration in viral load, CXCL12 silencing led to a significant reduction in type-I interferon production compared to both ZIKV-infected and uninfected groups. Furthermore, we found grip strength deficits in the group treated with siRNA-LNP compared to the other groups. Our data suggest a correlation between the upregulated pro-inflammatory cytokines and the observed decrease in strength. Collectively, our results provide evidence that CXCL12 silencing exerts a regulatory influence on the immune response in the brain during ZIKV infection. In addition, the modulation of T-cell activation following CXCL12 silencing provides valuable insights into potential protective mechanisms against ZIKV, offering novel perspectives for combating this infection.

The role of PKC and PKD in CXCL12 and CXCL13 directed malignant melanoma and acute monocytic leukemic cancer cell migration

Cancer metastasis is the leading cause of cancer related mortality. Chemokine receptors and proteins in their downstream signalling axis represent desirable therapeutic targets for the prevention of metastasis. Despite this, current therapeutics have experienced limited success in clinical trials due to a lack of insight into the downstream signalling pathway of specific chemokine receptor cascades in different tumours. In this study, we investigated the role of protein kinase C (PKC) and protein kinase D (PKD) in CXCL12 and CXCL13 stimulated SK-MEL-28 (malignant melanoma) and THP-1 (acute monocytic leukaemia) cell migration. While PKC and PKD had no active role in CXCL12 or CXCL13 stimulated THP-1 cell migration, PKC and PKD inhibition reduced CXCL12 stimulated migration and caused profound effects upon the cytoskeleton of SK-MEL-28 cells. Furthermore, only PKC and not PKD inhibition reduced CXCL13 stimulated migration in SK-MEL-28 cells however PKC inhibition failed to stimulate any changes to the actin cytoskeleton. These findings indicate that PKC inhibitors would be a useful therapeutic for the prevention of both CXCL12 and CXCL13 stimulated migration and PKD inhibitors for CXCL12 stimulated migration in malignant melanoma.

Detection of lymph node metastasis in colon cancer by ectopically expressed fibroblast markers FOXQ1 and THBS2

Introduction

Approximately 25% of colon cancer (CC) patients having curative surgery will relapse. Therefore, it is crucial to identify patients with increased recurrence risk to offer them adjuvant chemotherapy. Three markers with prominent expression in fibroblasts: forkhead box Q1 (FOXQ1), matrix metalloproteinase-11 (MMP11), and thrombospondin-2 (THBS2), and the fibroblast expressed chemokine CXCL12 were selected for studies because of the critical role of fibroblasts in the microenvironment of the tumor.

Methods

The expression levels of the biomarkers were assessed in primary CC tumors, lymph nodes of CC patients and controls, and CC cell lines at mRNA and protein levels by real-time qRT-PCR and immunohistochemistry, respectively.

Results

FOXQ1, MMP11, and THBS2 mRNAs were expressed at significantly higher levels in primary tumors compared to normal colon (P=0.002, P<0.0001, and P<0.0001, respectively). In contrast, CXCL12 mRNA levels were higher in normal colon tissue. FOXQ1, MMP11, and THBS2 levels were also expressed at significantly higher levels in metastasis-positive lymph nodes compared to both metastasis-negative- and control nodes (P<0.0001/P=0.002, P<0.0001/P<0.0001, and P<0.0001/P<0.0001, respectively). Immuno-morphometry revealed that 30-40% of the tumor cells expressed FOXQ1, MMP11, and THBS2. FOXQ1 and THBS2 were barely detected in normal colon epithelium (P<0.0001), while MMP11 was expressed in normal colon epithelium at high levels.

Discussion

We conclude that CC tumor cells show ectopic expression of FOXQ1 and THBS2 possibly making these tumor cells independent of fibroblast cell support. The high expression levels of these two biomarkers in metastatic lymph nodes suggest that they are potential indicators of patients at risk for recurrence.

Placental insufficiency and heavier placentas in sheep after suppressing CXCL12/CXCR4 signaling during implantation†

During implantation, trophoblast cell invasion and differentiation is predominantly important to achieving proper placental formation and embryonic development. The chemokine, C-X-C motif chemokine ligand 12 (CXCL12) working through its receptor C-X-C motif chemokine receptor 4 (CXCR4) is implicated in implantation and placentation but precise roles of this axis are unclear. Suppressing CXCL12/CXCR4 signaling at the fetal-maternal interface in sheep reduces trophoblast invasion, disrupts uterine remodeling, and diminishes placental vascularization. We hypothesize these negative impacts during implantation will manifest as compromised fetal and placental growth at midgestation. To test, on day 12 postbreeding, osmotic pumps were surgically installed in 30 ewes and delivered intrauterine CXCR4 inhibitor or saline for 7 or 14 days. On day 90, fetal/maternal tissues were collected, measured, weighed, and maternal (caruncle) and fetal (cotyledon) placenta components separated and analyzed. The objectives were to determine if (i) suppressing CXCL12/CXCR4 during implantation results in reduced fetal and placental growth and development and (ii) if varying the amount of time CXCL12/CXCR4 is suppressed impacts fetal/placental development. Fetal weights were similar; however greater placental weight and placentome numbers occurred when CXCL12/CXCR4 was suppressed for 14 days. In caruncles, greater abundance of fibroblast growth factor 2, vascular endothelial growth factor A, vascular endothelial growth factor A receptor 1 (FLT-1), and placental growth factor were observed after suppressing CXCL12/CXCR4. Similar results occurred in cotyledons except less vascular endothelial growth factor in 7 day group and less fibroblast growth factor in 14 day group. Our data underscore the importance of CXCL12/CXCR4 signaling during placentation and provide strong evidence that altering CXCL12-mediated signaling induces enduring placental effects manifesting later in gestation.

Hedgehog signalling in Foxd1+ embryonic kidney stromal progenitors controls nephron formation via Cxcl12 and Wnt5a

Congenital anomalies of the kidney and urinary tract (CAKUT) are characterised by a spectrum of structural and histologic abnormalities and are the major cause of childhood kidney failure. During kidney morphogenesis, the formation of a critical number of nephrons is an embryonic process supported, in part, by signalling between nephrogenic precursors and Foxd1-positive stromal progenitor cells. Low nephron number and abnormal patterning of the stroma are signature pathological features among CAKUT phenotypes with decreased kidney function. Despite their critical contribution to CAKUT pathogenesis, the mechanisms that underlie a low nephron number and the functional contribution of a disorganised renal stroma to nephron number are both poorly defined. Here, we identify a primary pathogenic role for increased Hedgehog signalling in embryonic renal stroma in the genesis of congenital low nephron number. Pharmacologic activation of Hedgehog (Hh) signalling in human kidney organoid tissue decreased the number of nephrons and generated excess stroma. The mechanisms underlying these pathogenic effects were delineated in genetic mouse models in which Hh signalling was constitutively activated in a cell lineage-specific manner. Cre-mediated excision of Ptch1 in Foxd1+ stromal progenitor cells, but not in Six2+ nephrogenic precursor cells, generated kidney malformation, identifying the stroma as a driver of low nephron number. Single-cell RNA sequencing analysis identified Cxcl12 and Wnt5a as downstream targets of increased stromal Hh signalling, findings supported by analysis in human kidney organoids. In vivo deficiency of Cxcl12 or Wnt5a in mice with increased stromal Hh signalling improved nephron endowment. These results demonstrate that dysregulated Hh signalling in embryonic renal stromal cells inhibits nephron formation in a manner dependent on Cxcl12 and Wnt5a. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

High density of CXCL12-positive immune cell infiltration predicts chemosensitivity and recurrence-free survival in ovarian carcinoma

BACKGROUND

Ovarian carcinoma is the most lethal gynecologic malignancy because of its late diagnosis, extremely high recurrence rate, and limited curative treatment options. In clinical practice, high-grade serous carcinoma (HGSC) predominates due to its frequency, high aggressiveness, and rapid development of drug resistance. Recent evidence suggests that CXCL12 is an important immunological factor in ovarian cancer progression. Therefore, we investigated the predictive and prognostic significance of the expression of this chemokine in tumor and immune cells in patients with HGSC.

METHODS

We studied a cohort of 47 primary high-grade serous ovarian carcinomas and their associated recurrences. A tissue microarray was constructed to evaluate the CXCL12 immunostained tumor tissue. CXCL12 expression was evaluated and statistically analyzed to correlate clinicopathologic data, overall survival, and recurrence-free survival.

RESULTS

A high proportion of CXCL12 + positive immune cells in primary ovarian serous carcinoma correlated significantly with chemosensitivity (p = 0.005), overall survival (p = 0.021), and longer recurrence-free survival (p = 0.038). In recurrent disease, high expression of CXCL12 was also correlated with better overall survival (p = 0.040). Univariate and multivariate analysis revealed that high CXCL12 + tumor-infiltrating immune cells (TICs) (HR 0.99, p = 0.042, HR 0.99, p = 0.023, respectively) and combined CXCL12 + /CD66b + infiltration (HR 0.15, p = 0.001, HR 0.13, p = 0.001, respectively) are independent favorable predictive markers for recurrence-free survival.

CONCLUSION

A high density of CXCL12 + TICs predicts a good response to chemotherapy, leading to a better overall survival and a longer recurrence-free interval. Moreover, with concomitant high CXCL12/CD66b TIC density, it is an independent favorable predictor of recurrence-free survival in patients with ovarian carcinoma.

The development of potent, competitive CXCR4 antagonists for the prevention of cancer metastasis

Cancer metastasis is the cause of up to 90 % of cancer related mortality. The CXCR4 receptor and its cognate ligand, CXCL12, have major roles in enabling cancer metastasis and consequently, the CXCR4 receptor has become an attractive therapeutic target for the prevention of metastasis. Despite this, CXCR4 antagonists have had limited success in clinical trials due to cellular toxicity and poor stability and efficacy. In this study, we developed a novel, competitive CXCR4 antagonist (IS4) that through copper-catalysed-azide-alkyne-cycloaddition can be clicked to other chemical moieties such as fluorescent dyes (IS4-FAM) for CXCR4-based imaging. We determined that these CXCR4 antagonists were non-toxic and could be used to specifically label the CXCR4 receptor. Furthermore, IS4 and IS4-FAM inhibited CXCL12-stimulated cancer cell migration and Ca2+ release in both adherent and suspension cell lines with similar or improved potency as compared to two literature CXCR4 antagonists. Our results highlight the potential of IS4 and IS4-FAM as research tools and as potent CXCR4 antagonists for the prevention of metastasis.

Disruption of cholangiocyte-B cell crosstalk by blocking the CXCL12-CXCR4 axis alleviates liver fibrosis

B cells can promote liver fibrosis, but the mechanism of B cell infiltration and therapy against culprit B cells are lacking. We postulated that the disruption of cholangiocyte-B-cell crosstalk could attenuate liver fibrosis by blocking the CXCL12-CXCR4 axis via a cyclooxygenase-2-independent effect of celecoxib. In wild-type mice subjected to thioacetamide, celecoxib ameliorated lymphocytic infiltration and liver fibrosis. By single-cell RNA sequencing and flow cytometry, CXCR4 was established as a marker for profibrotic and liver-homing phenotype of B cells. Celecoxib reduced liver-homing B cells without suppressing CXCR4. Cholangiocytes expressed CXCL12, attracting B cells to fibrotic areas in human and mouse. The proliferation and CXCL12 expression of cholangiocytes were suppressed by celecoxib. In CXCL12-deficient mice, liver fibrosis was also attenuated with less B-cell infiltration. In the intrahepatic biliary epithelial cell line HIBEpiC, bulk RNA sequencing indicated that both celecoxib and 2,5-dimethyl-celecoxib (an analog of celecoxib that does not show a COX-2-dependent effect) regulated the TGF-β signaling pathway and cell cycle. Moreover, celecoxib and 2,5-dimethyl-celecoxib decreased the proliferation, and expression of collagen I and CXCL12 in HIBEpiC cells stimulated by TGF-β or EGF. Taken together, liver fibrosis can be ameliorated by disrupting cholangiocyte-B cell crosstalk by blocking the CXCL12-CXCR4 axis with a COX-2-independent effect of celecoxib.

Cancer-associated fibroblasts-derived CXCL12 enhances immune escape of bladder cancer through inhibiting P62-mediated autophagic degradation of PDL1

BACKGROUND

Cancer-associated fibroblasts (CAFs), the predominant stromal cell of tumor microenvironment (TME), play an important role in tumor progression and immunoregulation by remodeling extracellular matrix (ECM) and secreting cytokines. However, little is known about the details of the underlying mechanism in bladder cancer.

METHODS

Bioinformatics analysis was performed to analyze the prognostic value of CAFs and CXCL12 using GEO, TCGA and SRA databases. The effects of CXCL12 on bladder cancer progression were investigated through in vitro and in vivo assays. The biological mechanism of the effect of CXCL12 on PDL1 were investigated using western blotting, immunoprecipitation, RT-PCR, immunofluorescence, mass spectrometry, protein stability, and flow cytometry.

RESULTS

The results demonstrated that CAFs-derived CXCL12 promoted cancer cell migration and invasion and upregulated PDL1. Mechanistically, upon binding to its specific receptor, CXCL12 activated the downstream JAK2/STAT3 pathway and rapidly up-regulated the expression of deubiquitinase CYLD. CYLD deubiquitinated P62 causing P62 accumulation, which in turn inhibited the autophagic degradation of PDL1. In vivo experiments demonstrated that blocking CXCL12 inhibited tumor growth, reduced tumor PDL1 expression and increased immune cell infiltration.

CONCLUSIONS

This study revealed a novel mechanism for the role of CXCL12 in P62-mediated PDL1 autophagic regulation. Combined application of CXCL12 receptor blocker and PD1/PDL1 blocker can more effectively inhibit PDL1 expression and enhance antitumor immune response. Targeting CAFs-derived CXCL12 may provide an effective strategy for immunotherapy in bladder cancer.

Molecular characterization of the CXCR4 / CXCR7 axis in germ cell tumors and its targetability using nanobody-drug-conjugates

Being stimulated by the chemokine CXCL12, the CXCR4 / CXCR7 cascade is involved in tumor proliferation, migration, and metastasis. The interaction between CXCL12, secreted by cells from the microenvironment, and its receptors is complex and has been ascribed to promote chemotherapy resistance. However, the role of this signaling axis and its targetability in germ cell tumors (GCT) is not fully understood. Thus, this study investigated the therapeutic efficacy of a nanobody-drug-conjugate targeting CXCR4 (CXCR4-NDC) and functionally characterized this signaling pathway in GCT using small molecule inhibitors and nanobodies. As shown by diminished cell viability, enhanced apoptosis induction, and detection of mitotic catastrophes, we confirmed the cytotoxic efficacy of the CXCR4-NDC in CXCR4+-GCT cells (i.e. seminoma and yolk-sac tumor), while non-malignant CXCR4--fibroblasts, remained largely unaffected. Stimulation of CXCR4+ / CXCR7+-GCT cells with CXCL12 resulted in an enhanced proliferative and migratory capacity, while this effect could be reverted using CXCR4 inhibitors or a CXCR7-nanobody. Molecularly, the CXCR4 / CXCR7-signaling cascade could be activated independently of MAPK (ERK1 / 2)-phosphorylation. Although, in CXCR4- / CXCR7--embryonal carcinoma cells, CXCR7-expression was re-induced upon inhibition of ERK1 / 2-signaling. This study identified a nanobody-drug-conjugate targeting CXCR4 as a putative therapeutic option for GCT, i.e. seminoma and yolk-sac tumors. Furthermore, this study shed light on the functional role of the CXCR4 / CXCR7 / CXCL12-signaling cascade in GCT, demonstrating an important influence on proliferation and migration.

Exosome-derived miR-372-5p promotes stemness and metastatic ability of CRC cells by inducing macrophage polarization

Colorectal cancer (CRC) is the most common malignancy in the digestive system, and tumor metastasis is the main cause of death in clinical patients with CRC. It has been shown that exosomes promote phenotypic changes in macrophages and tumor metastasis in the CRC tumor microenvironment. In this study, we used miRNA-seq technology to screen out the highly expressed miR-372-5p among the miRNAs differentially expressed in plasma exosomes of clinical CRC patients. It was found that miR-372-5p highly expressed in HCT116 exosomes could be phagocytosed by macrophages and promote their polarization into M2 macrophages by regulating the PTEN/AKT pathway. Meanwhile, co-culture of CRC cells with conditioned medium (CM) of macrophages enhanced the EMT, stemness and metastasis of CRC cells. Mechanistically, CRC cells exosome-derived miR-372-5p induced polarized M2 macrophages to secrete chemokine C-X-C-Motif Ligand 12 (CXCL12), which activated the WNT/β-catenin pathway to promote the EMT, stemness and metastatic ability of CRC cells. In summary, this study elucidated the molecular mechanism of exosomal miR-372-5p promoting metastasis and stemness in CRC, which may provide new therapeutic targets for CRC metastasis and prognosis assessment.

Genetic clues to COVID-19 severity: exploring the stromal cell-derived factor-1/CXCL12 rs2839693 polymorphism in adult Egyptians

BACKGROUND

A novel corona virus called SARS-CoV-2 was identified at the end of December 2019, and the illness induced by it was designated as coronavirus disease 2019 (COVID-19). Severity of the disease could vary significantly since most of the infected individuals experience mild to moderate respiratory symptoms and recover without specialized care. Genetic polymorphisms have implications in influencing the varying degrees of COVID-19 severity. This study aims to assess the potential association between the CXCL12 rs2839693 polymorphism and the severity of COVID-19 in Assiut University Quarantine Hospital during the period from May 2022 to August 2022.

METHODS

The present study is a cross-sectional study and is applied to 300 COVID-19 patients confirmed by RT-PCR admitted to Assiut University Quarantine Hospital from May 2022 to August 2022. Based on the clinical symptoms, the recruited participants had been divided into two groups. Group I involved mild or moderate cases; Group II involved severe or critical conditions. The rs2839693 polymorphism was detected by real time PCR using TaqMan assay probe.

RESULTS

The frequency of the T allele and the TT genotype was significantly higher in the severe or critical group compared with the mild or moderate group (p value < 0.001). C-reactive protein (CRP) and D-dimers are significantly elevated in the combined variants (CT + TT) and the TT compared with the CC (P value 0.006 and 0.017 respectively) and the CC,CT genotypes (p value 0.019 and 0.002 respectively). The combined variants (CT + TT) of CXCL12 were found to be independent predictors to severe or critical COVID-19 risk with P value =  < 0.001, OR = 3.034& 95% CI = 1.805-5.098.

CONCLUSION

Our findings revealed that CXCL12 rs2839693 had a role in the development and seriousness of COVID-19. Patients with the TT genotype or the T allele at increased risk developed severe or critical rather than mild or moderate disease.

CD13 facilitates immune cell migration and aggravates acute injury but promotes chronic post-stroke recovery

INTRODUCTION

Acute stroke leads to the activation of myeloid cells. These cells express adhesion molecules and transmigrate to the brain, thereby aggravating injury. Chronically after stroke, repair processes, including angiogenesis, are activated and enhance post-stroke recovery. Activated myeloid cells express CD13, which facilitates their migration into the site of injury. However, angiogenic blood vessels which play a role in recovery also express CD13. Overall, the specific contribution of CD13 to acute and chronic stroke outcomes is unknown.

METHODS

CD13 expression was estimated in both mice and humans after the ischemic stroke. Young (8-12 weeks) male wild-type and global CD13 knockout (KO) mice were used for this study. Mice underwent 60 min of middle cerebral artery occlusion (MCAO) followed by reperfusion. For acute studies, the mice were euthanized at either 24- or 72 h post-stroke. For chronic studies, the Y-maze, Barnes maze, and the open field were performed on day 7 and day 28 post-stroke. Mice were euthanized at day 30 post-stroke and the brains were collected for assessment of inflammation, white matter injury, tissue loss, and angiogenesis. Flow cytometry was performed on days 3 and 7 post-stroke to quantify infiltrated monocytes and neutrophils and CXCL12/CXCR4 signaling.

RESULTS

Brain CD13 expression and infiltrated CD13+ monocytes and neutrophils increased acutely after the stroke. The brain CD13+lectin+ blood vessels increased on day 15 after the stroke. Similarly, an increase in the percentage area CD13 was observed in human stroke patients at the subacute time after stroke. Deletion of CD13 resulted in reduced infarct volume and improved neurological recovery after acute stroke. However, CD13KO mice had significantly worse memory deficits, amplified gliosis, and white matter damage compared to wild-type animals at chronic time points. CD13-deficient mice had an increased percentage of CXCL12+cells but a reduced percentage of CXCR4+cells and decreased angiogenesis at day 30 post-stroke.

CONCLUSIONS

CD13 is involved in the trans-migration of monocytes and neutrophils after stroke, and acutely, led to decreased infarct size and improved behavioral outcomes. However, loss of CD13 led to reductions in post-stroke angiogenesis by reducing CXCL12/CXCR4 signaling.

The interplay of FLT3 and CXCR4 in acute myeloid leukemia: an ongoing debate

FLT3 mutations are very frequent in AML and utilization of FLT3 inhibitors as approved treatment options are very common. Despite the initial success of inhibitor treatment, the development of resistances against this treatment is a major challenge in AML therapy. One of the mechanisms causing resistance is the homing of the leukemic cells in the protective niche of the bone marrow microenvironment (BMM). A pathway mediating homing to the BMM and leukemic cell survival is the CXCL12/CXCR4 axis. The analysis of patient samples in several independent studies indicated that FLT3-ITD expression led to higher CXCR4 surface expression. However, several in vitro studies reported contradictory findings, suggesting that FLT3-ITD signaling negatively influenced CXCR4 expression. In this commentary, we provide an overview summarizing the studies dealing with the relationship of FLT3 and CXCR4. Taken together, the current research status is not sufficient to answer the question whether FLT3 and CXCR4 act together or independently in leukemia progression. Systematic analyses in model cell systems are needed to understand the interplay between FLT3 and CXCR4, since this knowledge could lead to the development of more effective treatment strategies for AML patients.

ABCF1/CXCL12/CXCR4 Enhances Glioblastoma Cell Proliferation, Migration, and Invasion by Activating the PI3K/AKT Signal Pathway

Glioblastoma (GBM) is the most prevalent and fatal form of brain tumor, which is associated with a poor prognosis. ATP-binding cassette subfamily F member 1 (ABCF1) is an E2 ubiquitin-conjugating enzyme, which is implicated in regulating immune responses and tumorigenesis. Aberrant E3 ubiquitylation has been evidenced in GBM. However, the role of ABCF1 in GBM needs to be further explored. The expression of ABCF1, CXC chemokine ligand 12 (CXCL12), and CXC chemokine receptor 4 (CXCR4) in GBM tissues was examined by the GEPIA tool, real-time PCR and Western blotting. HMC3, U251MG, and LN-229 cells were cultured and transfected with shRNA targeting ABCF1 and ABCF1 plasmids. The proliferative, migrative, and invasive ability of cells was detected. Western blotting was used to detect the levels of phosphorylated phosphatidylinositol 3-kinase (PI3K) and phosphorylated protein kinase B (AKT). We observed that GBM tissues had higher ABCF1, CXCL12, and CXCR4 expression levels. The expression levels of CXCL12 and CXCR4 were enhanced by ABCF1 overexpression, which were significantly reversed by silence of ABCF1 in GBM cells. Silencing ABCF1 or CXCR4 inhibition weakened the capacity of GBM cell growth, migration, and invasion, while ectopic ABCF1 expression or CXCL12 treatment enhanced the cellular function of GBM cells. Furthermore, p-PI3K and p-AKT protein levels were downregulated by ABCF1 knockdown or CXCR4 blockade, which were prompted by ABCF1 overexpression or CXCL12 supplement. The ABCF1-CXCL12-CXCR4 axis was identified as a key player in GBM cell survival and metastasis by activating the PI3K/AKT signaling pathway in GBM cells.

Hematopoietic cell-derived IL-15 supports NK cell development in scattered and clustered localization within the bone marrow

Natural killer (NK) cells are innate immune cells critical for protective immune responses against infection and cancer. Although NK cells differentiate in the bone marrow (BM) in an interleukin-15 (IL-15)-dependent manner, the cellular source of IL-15 remains elusive. Using NK cell reporter mice, we show that NK cells are localized in the BM in scattered and clustered manners. NK cell clusters overlap with monocyte and dendritic cell accumulations, whereas scattered NK cells require CXCR4 signaling. Using cell-specific IL-15-deficient mice, we show that hematopoietic cells, but not stromal cells, support NK cell development in the BM through IL-15. In particular, IL-15 produced by monocytes and dendritic cells appears to contribute to NK cell development. These results demonstrate that hematopoietic cells are the IL-15 niche for NK cell development in the BM and that BM NK cells are present in scattered and clustered compartments by different mechanisms, suggesting their distinct functions in the immune response.

Plasma levels of chemokines CCL2 and CXCL12 in female dogs with malignant mammary gland tumours without and with metastases

The aim of this study was to evaluate the plasma levels of chemokines CCL2 and CXCL12 in female dogs with malignant mammary gland tumours without and with metastases. The concentrations of CCL2 and CXCL12 were determined in 25 female dogs with malignant mammary gland tumours (15 without metastases and 10 with metastases) and 10 healthy control animals using a specific canine ELISA assay. The mean plasma concentrations of CCL2 and CXCL12 were significantly higher (p<0.05) in the metastatic group compared to the control group. Moreover, the concentrations of these chemokines were markedly higher in the dogs with metastases than in those without metastases; however, a statistically significant difference was not found. The concentrations of both tested chemokines were numerically increased in the dogs with grade 2 and grade 3 carcinomas compared to the dogs with grade 1 carcinomas but the differences did not reach statistical significance. In conclusion, the results of our study demonstrate that plasma concentrations of chemokines CCL2 and CXCL12 are significantly increased in the dogs with metastatic malignant mammary gland tumours compared to the healthy dogs and show an upward trend compared to those without metastases. However, clarifying whether the increase of these chemokines is a cause or an effect of metastasis in female dogs with malignant mammary gland tumours as well as their potential role in metastatic process requires further research.

C-X-C motif chemokine ligand 12 improves the developmental potential of bovine oocytes by activating SH2 domain-containing tyrosine phosphatase 2 during maturation†

In vitro maturation of mammalian oocytes is an important means in assisted reproductive technology. Most bovine immature oocytes complete nuclear maturation, but less than half develop to the blastocyst stage after fertilization. Thus, inefficient in vitro production is mainly caused by a suboptimal in vitro culture process, in which oocyte quality appears to be the limiting factor. In our study, a potential maternal regulator, C-X-C motif chemokine ligand 12, was identified by analyzing transcriptome data. C-X-C motif chemokine ligand 12 supplementation promoted the developmental potential of oocytes by improving protein synthesis and reorganizing cortical granules and mitochondria during in vitro maturation, which eventually increased blastocyst formation efficiency and cell number after parthenogenesis, fertilization, and cloning. All these promoting effects by C-X-C motif chemokine ligand 12 were achieved by activating SH2 domain-containing tyrosine phosphatase 2, thereby promoting the mitogen-activated protein kinase signaling pathway. These findings provide an in vitro maturation system that closely resembles the maternal environment to provide high-quality oocytes for in vitro production.

A CXCR4 inhibitor (balixafortide) enhances docetaxel-mediated antitumor activity in a murine model of prostate cancer bone metastasis

BACKGROUND

Prostate cancer (PCa) bone metastases have been shown to be more resistant to docetaxel than soft tissue metastases. The proinflammatory chemokine receptor CXCR4 has been shown to confer resistance to docetaxel (DOC) in PCa cells. Balixafortide (BLX) is a protein epitope mimetic inhibitor of CXCR4. Accordingly, we hypothesized that BLX would enhance DOC-mediated antitumor activity in PCa bone metastases.

METHODS

PC-3 luciferase-labeled cells were injected into the tibia of mice to model bone metastases. Four treatment groups were created: vehicle, DOC (5 mg/kg), BLX (20 mg/kg), and combo (receiving both DOC and BLX). Mice were injected twice daily subcutaneously with either vehicle or BLX starting on Day 1 and weekly intraperitoneally with DOC starting on Day 1. Tumor burden was measured weekly via bioluminescent imaging. At end of study (29 days), radiographs were taken of the tibiae and blood was collected. Serum levels of TRAcP, IL-2, and IFNγ levels were measured using ELISA. Harvested tibiae were decalcified and stained for Ki67, cleaved caspase-3, and CD34 positive cells or microvessels were quantified.

RESULTS

Tumor burden was lower in the combo group compared to the DOC alone group. Treatment with the combination had no impact on the number of mice with osteolytic lesions, however the area of osteolytic lesions was lower in the combo group compared to the vehicle and BLX groups, but not the DOC group. Serum TRAcP levels were lower in the combo compared to vehicle group, but not the other groups. No significant difference in Ki67 staining was found among the groups; whereas, cleaved caspase-3 staining was lowest in the Combo group and highest in the BLX group. The DOC and combo groups had more CD34+ microvessels than the control and BLX groups. There was no difference between the treatment groups for IL-2, but the combo group had increased levels of IFNγ compared to the DOC group.

CONCLUSIONS

Our data demonstrate that a combination of BAL and DOC has greater antitumor activity in a model of PCa bone metastases than either drug alone. These data support further evaluation of this combination in metastatic PCa.

Glia Cells Control Olfactory Neurogenesis by Fine-Tuning CXCL12

Olfaction depends on lifelong production of sensory neurons from CXCR4 expressing neurogenic stem cells. Signaling by CXCR4 depends on the concentration of CXCL12, CXCR4's principal ligand. Here, we use several genetic models to investigate how regulation of CXCL12 in the olfactory stem cell niche adjusts neurogenesis. We identify subepithelial tissue and sustentacular cells, the olfactory glia, as main CXCL12 sources. Lamina propria-derived CXCL12 accumulates on quiescent gliogenic stem cells via heparan sulfate. Additionally, CXCL12 is secreted within the olfactory epithelium by sustentacular cells. Both sustentacular-cell-derived and lamina propria-derived CXCL12 are required for CXCR4 activation. ACKR3, a high-affinity CXCL12 scavenger, is expressed by mature glial cells and titrates CXCL12. The accurate adjustment of CXCL12 by ACKR3 is critical for CXCR4-dependent proliferation of neuronal stem cells and for proper lineage progression. Overall, these findings establish precise regulation of CXCL12 by glia cells as a prerequisite for CXCR4-dependent neurogenesis and identify ACKR3 as a scavenger influencing tissue homeostasis beyond embryonic development.

The Relationships between Cerebrospinal Fluid Glial (CXCL12, CX3CL, YKL-40) and Synaptic Biomarkers (Ng, NPTXR) in Early Alzheimer's Disease

In addition to amyloid and tau pathology in the central nervous system (CNS), inflammatory processes and synaptic dysfunction are highly important mechanisms involved in the development and progression of dementia diseases. In the present study, we conducted a comparative analysis of selected pro-inflammatory proteins in the CNS with proteins reflecting synaptic damage and core biomarkers in mild cognitive impairment (MCI) and early Alzheimer's disease (AD). To our knowledge, no studies have yet compared CXCL12 and CX3CL1 with markers of synaptic disturbance in cerebrospinal fluid (CSF) in the early stages of dementia. The quantitative assessment of selected proteins in the CSF of patients with MCI, AD, and non-demented controls (CTRL) was performed using immunoassays (single- and multiplex techniques). In this study, increased CSF concentration of CX3CL1 in MCI and AD patients correlated positively with neurogranin (r = 0.74; p < 0.001, and r = 0.40; p = 0.020, respectively), ptau181 (r = 0.49; p = 0.040), and YKL-40 (r = 0.47; p = 0.050) in MCI subjects. In addition, elevated CSF levels of CXCL12 in the AD group were significantly associated with mini-mental state examination score (r = -0.32; p = 0.040). We found significant evidence to support an association between CX3CL1 and neurogranin, already in the early stages of cognitive decline. Furthermore, our findings indicate that CXCL12 might be a useful marker for tract severity of cognitive impairment.

CXCL12/CXCR4/CXCR7 axis in placenta tissues of patients with placenta previa

CXCR4 and CXCR7 have been revealed to be receptors of CXCL12. This research was designed to probe the expression of chemokine CXCL12 and its receptors CXCR4 and CXCR7 in placental tissues of patients with placenta previa and the effect of CXCL12/CXCR4/CXCR7 axis on the biological functions of human trophoblast cells. CXCL12, CXCR4, and CXCR7 expression in placental tissue from patients with placenta previa and healthy puerperae was detected. CXCL12, CXCR4, and CXCR7 expression in human trophoblast cell lines (HTR8/SVneo cells) was assessed after suppression or overexpression of CXCL12, CXCR4, and CXCR7. The cell proliferative, invasive, and migratory capacities were also evaluated in HTR8/SVneo cells after suppression or overexpression of CXCL12, CXCR4, and CXCR7. CXCL12, CXCR4, and CXCR7 expression was elevated in placental tissues from patients with placenta previa. Downregulation of CXCL12, CXCR4, and CXCR7 could lead to decreased mRNA levels of CXCL12, CXCR4, and CXCR7 in HTR-8/SVneo cells, which was accompanied by diminished cell proliferative, migratory, and invasive capabilities. Overexpression of CXCL12, CXCR4, and CXCR7 genes presented an opposite tendency. CXCL12, CXCR4, and CXCR7 are highly expressed in placental tissues of patients with placenta previa and induce the biological activities of HTR8/SVneo cells.

G protein activation via chemokine (C-X-C motif) receptor 4 and α1b -adrenoceptor is ligand and heteromer-dependent

It is unknown whether heteromerization between chemokine (C-X-C motif) receptor 4 (CXCR4), atypical chemokine receptor 3 (ACKR3) and α1b -adrenoceptor (α1b -AR) influences effects of the CXCR4/ACKR3 agonist chemokine (C-X-C motif) ligand 12 (CXCL12) and the noncognate CXCR4 agonist ubiquitin on agonist-promoted G protein activation. We provide biophysical evidence that both ligands stimulate CXCR4-mediated Gαi activation. Unlike CXCL12, ubiquitin fails to recruit β-arrestin. Both ligands differentially modulate the conformation of CXCR4:ACKR3 heterodimers and its propensity to hetero-trimerize with α1b -AR. CXCR4:ACKR3 heterodimerization reduces the potency of CXCL12, but not of ubiquitin, to activate Gαi. Ubiquitin enhances phenylephrine-stimulated α1b -AR-promoted Gαq activation from hetero-oligomers comprising CXCR4. CXCL12 enhances phenylephrine-stimulated α1b -AR-promoted Gαq activation from CXCR4:α1b -AR heterodimers and reduces phenylephrine-stimulated α1b -AR-promoted Gαq activation from ACKR3 comprising heterodimers and trimers. Our findings suggest heteromer and ligand-dependent functions of the receptor partners.