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CC chemokine receptor 2 (CCR2) has been linked to many inflammatory and immune diseases, making it a relevant drug target. Yet, all CCR2 antagonists developed so far have failed in clinical trials; thus, novel strategies are needed to target this receptor. Targeted protein degradation represents a novel approach to inhibit protein function by hijacking the cellular degradation machinery, such as the proteasome, to degrade the protein of interest. Here, we aimed to determine the amenability of CCR2 to chemically induced degradation by using a CCR2 fusion protein containing a HaloTag7 and HiBiT tag (CCR2-HaloTag-HiBiT). After characterization of the CCR2 construct, we used luminescence-based assays and immunofluorescence to quantify CCR2 levels, as well as a label-free, phenotypic assay to investigate the functional effect of CCR2 degradation. Treatment with HaloPROTAC3, which selectively degrades HaloTag fusion proteins, led to concentration- and time-dependent degradation of CCR2-HaloTag-HiBiT. HaloPROTAC3 induced degradation via the proteasome, as degradation was fully blocked with proteasomal inhibitors. Finally, functional assays showed that degradation of CCR2-HaloTag-HiBiT leads to a reduced functional response after agonist stimulation. Overall, our results indicate that CCR2 is amenable to targeted degradation, paving the way for the future development of CCR2 chemical degraders. [ABSTRACT FROM AUTHOR]

Investigating the role of podocytes in proteinuric disease is imperative to address the increasing global burden of chronic kidney disease (CKD). Studies strongly implicate increased levels of monocyte chemoattractant protein-1 (MCP-1/CCL2) in proteinuric CKD. Since podocytes express the receptor for MCP-1 (i.e., CCR2), we hypothesized that podocyte-specific MCP-1 production in response to stimuli could activate its receptor in an autocrine manner, leading to further podocyte injury. To test this hypothesis, we generated podocyte-specific MCP-1 knockout mice (Podo-Mcp-1fl/fl) and exposed them to proteinuric injury induced by either angiotensin II (Ang II; 1.5 mg/kg/d, osmotic minipump) or Adriamycin (Adr; 18 mg/kg, intravenous bolus). At baseline, there were no between-group differences in body weight, histology, albuminuria, and podocyte markers. After 28 days, there were no between-group differences in survival, change in body weight, albuminuria, kidney function, glomerular injury, and tubulointerstitial fibrosis. The lack of protection in the knockout mice suggests that podocyte-specific MCP-1 production is not a major contributor to either Ang II- or Adr-induced glomerular disease, implicating that another cell type is the source of pathogenic MCP-1 production in CKD. [ABSTRACT FROM AUTHOR]

CC chemokine receptor 2 (CCR2) has been linked to many inflammatory and immune diseases, making it a relevant drug target. Yet, all CCR2 antagonists developed so far have failed in clinical trials; thus, novel strategies are needed to target this receptor. Targeted protein degradation represents a novel approach to inhibit protein function by hijacking the cellular degradation machinery, such as the proteasome, to degrade the protein of interest. Here, we aimed to determine the amenability of CCR2 to chemically induced degradation by using a CCR2 fusion protein containing a HaloTag7 and HiBiT tag (CCR2-HaloTag-HiBiT). After characterization of the CCR2 construct, we used luminescence-based assays and immunofluorescence to quantify CCR2 levels, as well as a label-free, phenotypic assay to investigate the functional effect of CCR2 degradation. Treatment with HaloPROTAC3, which selectively degrades HaloTag fusion proteins, led to concentration- and time-dependent degradation of CCR2-HaloTag-HiBiT. HaloPROTAC3 induced degradation via the proteasome, as degradation was fully blocked with proteasomal inhibitors. Finally, functional assays showed that degradation of CCR2-HaloTag-HiBiT leads to a reduced functional response after agonist stimulation. Overall, our results indicate that CCR2 is amenable to targeted degradation, paving the way for the future development of CCR2 chemical degraders.

Investigating the role of podocytes in proteinuric disease is imperative to address the increasing global burden of chronic kidney disease (CKD). Studies strongly implicate increased levels of monocyte chemoattractant protein-1 (MCP-1/CCL2) in proteinuric CKD. Since podocytes express the receptor for MCP-1 (i.e., CCR2), we hypothesized that podocyte-specific MCP-1 production in response to stimuli could activate its receptor in an autocrine manner, leading to further podocyte injury. To test this hypothesis, we generated podocyte-specific MCP-1 knockout mice (Podo-Mcp-1fl/fl) and exposed them to proteinuric injury induced by either angiotensin II (Ang II; 1.5 mg/kg/d, osmotic minipump) or Adriamycin (Adr; 18 mg/kg, intravenous bolus). At baseline, there were no between-group differences in body weight, histology, albuminuria, and podocyte markers. After 28 days, there were no between-group differences in survival, change in body weight, albuminuria, kidney function, glomerular injury, and tubulointerstitial fibrosis. The lack of protection in the knockout mice suggests that podocyte-specific MCP-1 production is not a major contributor to either Ang II- or Adr-induced glomerular disease, implicating that another cell type is the source of pathogenic MCP-1 production in CKD.

Homeostasis of the host immune system is regulated by white blood cells with a variety of cell surface receptors for cytokines. Chemotactic cytokines (chemokines) activate their receptors to evoke the chemotaxis of immune cells in homeostatic migrations or inflammatory conditions towards inflamed tissue or pathogens. Dysregulation of the immune system leading to disorders such as allergies, autoimmune diseases, or cancer requires efficient, fast-acting drugs to minimize the long-term effects of chronic inflammation. Here, we performed structure-based virtual screening (SBVS) assisted by the Keras/TensorFlow neural network (NN) to find novel compound scaffolds acting on three chemokine receptors: CCR2, CCR3, and one CXC receptor, CXCR3. Keras/TensorFlow NN was used here not as a typically used binary classifier but as an efficient multi-class classifier that can discard not only inactive compounds but also low- or medium-activity compounds. Several compounds proposed by SBVS and NN were tested in 100 ns all-atom molecular dynamics simulations to confirm their binding affinity. To improve the basic binding affinity of the compounds, new chemical modifications were proposed. The modified compounds were compared with known antagonists of these three chemokine receptors. Known CXCR3 compounds were among the top predicted compounds; thus, the benefits of using Keras/TensorFlow in drug discovery have been shown in addition to structure-based approaches. Furthermore, we showed that Keras/TensorFlow NN can accurately predict the receptor subtype selectivity of compounds, for which SBVS often fails. We cross-tested chemokine receptor datasets retrieved from ChEMBL and curated datasets for cannabinoid receptors. The NN model trained on the cannabinoid receptor datasets retrieved from ChEMBL was the most accurate in the receptor subtype selectivity prediction. Among NN models trained on the chemokine receptor datasets, the CXCR3 model showed the highest accuracy in differentiating the receptor subtype for a given compound dataset. [ABSTRACT FROM AUTHOR]

Atherosclerosis is driven by a diverse range of cellular and molecular processes. In the present study, we sought to better understand how statins mitigate proatherogenic inflammation. 48 male New Zealand rabbits were divided into eight groups, each including 6 animals. The control groups received normal chow for 90 and 120 days. Three groups underwent a hypercholesterolemic diet (HCD) for 30, 60, and 90 days. Another three groups underwent HCD for 3 months, followed by normal chow for one month, with or without rosuvastatin or fluvastatin. The cytokine and chemokine expressions were assessed in the samples of thoracic and abdominal aorta. Rosuvastatin significantly reduced MYD88, CCL4, CCL20, CCR2, TNF-α, IFN-β, IL-1b, IL-2, IL-4, IL-8, and IL-10, both in the thoracic and abdominal aorta. Fluvastatin also downregulated MYD88, CCR2, IFN-β, IFN-γ, IL-1b, IL-2, IL-4, and IL-10 in both aortic segments. Rosuvastatin curtailed the expression of CCL4, IFN-β, IL-2, IL-4, and IL-10 more effectively than fluvastatin in both types of tissue. MYD88, TNF-α, IL-1b, and IL-8 showed a stronger downregulation with rosuvastatin compared to fluvastatin only in the thoracic aorta. The CCL20 and CCR2 levels reduced more extensively with rosuvastatin treatment only in abdominal aortic tissue. In conclusion, statin therapy can halt proatherogenic inflammation in hyperlipidemic animals. Rosuvastatin may be more effective in downregulating MYD88 in atherosclerotic thoracic aortas. [ABSTRACT FROM AUTHOR]

Natural killer (NK) cells are a subset of lymphocytes that offer great potential for cancer immunotherapy due to their natural anti-tumor activity and the possibility to safely transplant cells from healthy donors to patients in a clinical setting. However, the efficacy of cell-based immunotherapies using both T and NK cells is often limited by a poor infiltration of immune cells into solid tumors. Importantly, regulatory immune cell subsets are frequently recruited to tumor sites. In this study, we overexpressed two chemokine receptors, CCR4 and CCR2B, that are naturally found on T regulatory cells and tumor-resident monocytes, respectively, on NK cells. Using the NK cell line NK-92 as well as primary NK cells from peripheral blood, we show that genetically engineered NK cells can be efficiently redirected using chemokine receptors from different immune cell lineages and migrate towards chemokines such as CCL22 or CCL2, without impairing the natural effector functions. This approach has the potential to enhance the therapeutic effect of immunotherapies in solid tumors by directing genetically engineered donor NK cells to tumor sites. As a future therapeutic option, the natural anti-tumor activity of NK cells at the tumor sites can be increased by co-expression of chemokine receptors with chimeric antigen receptors (CAR) or T cell receptors (TCR) on NK cells can be performed in the future. [ABSTRACT FROM AUTHOR]

Acute respiratory distress syndrome (ARDS) consists of uncontrolled inflammation that causes hypoxemia and reduced lung compliance. Since it is a complex process, not all details have been elucidated yet. In a well-controlled experimental murine model of lipopolysaccharide (LPS)-induced ARDS, the activity and viability of macrophages and neutrophils dictate the beginning and end phases of lung inflammation. C-C chemokine receptor type 2 (CCR2) is a critical chemokine receptor that mediates monocyte/macrophage activation and recruitment to the tissues. Here, we used CCR2-deficient mice to explore mechanisms that control lung inflammation in LPS-induced ARDS. CCR2−/− mice presented higher total numbers of pulmonary leukocytes at the peak of inflammation as compared to CCR2+/+ mice, mainly by enhanced influx of neutrophils, whereas we observed two to six-fold lower monocyte or interstitial macrophage numbers in the CCR2−/−. Nevertheless, the time needed to control the inflammation was comparable between CCR2+/+ and CCR2−/−. Interestingly, CCR2−/− mice presented higher numbers and increased proliferative rates of alveolar macrophages from day 3, with a more pronounced M2 profile, associated with transforming growth factor (TGF)-β and C-C chemokine ligand (CCL)22 production, decreased inducible nitric oxide synthase (Nos2), interleukin (IL)-1β and IL-12b mRNA expression and increased mannose receptor type 1 (Mrc1) mRNA and CD206 protein expression. Depletion of alveolar macrophages significantly delayed recovery from the inflammatory insult. Thus, our work shows that the lower number of infiltrating monocytes in CCR2−/− is partially compensated by increased proliferation of resident alveolar macrophages during the inflammation control of experimental ARDS. [ABSTRACT FROM AUTHOR]

Homeostasis of the host immune system is regulated by white blood cells with a variety of cell surface receptors for cytokines. Chemotactic cytokines (chemokines) activate their receptors to evoke the chemotaxis of immune cells in homeostatic migrations or inflammatory conditions towards inflamed tissue or pathogens. Dysregulation of the immune system leading to disorders such as allergies, autoimmune diseases, or cancer requires efficient, fast-acting drugs to minimize the long-term effects of chronic inflammation. Here, we performed structure-based virtual screening (SBVS) assisted by the Keras/TensorFlow neural network (NN) to find novel compound scaffolds acting on three chemokine receptors: CCR2, CCR3, and one CXC receptor, CXCR3. Keras/TensorFlow NN was used here not as a typically used binary classifier but as an efficient multi-class classifier that can discard not only inactive compounds but also low- or medium-activity compounds. Several compounds proposed by SBVS and NN were tested in 100 ns all-atom molecular dynamics simulations to confirm their binding affinity. To improve the basic binding affinity of the compounds, new chemical modifications were proposed. The modified compounds were compared with known antagonists of these three chemokine receptors. Known CXCR3 compounds were among the top predicted compounds; thus, the benefits of using Keras/TensorFlow in drug discovery have been shown in addition to structure-based approaches. Furthermore, we showed that Keras/TensorFlow NN can accurately predict the receptor subtype selectivity of compounds, for which SBVS often fails. We cross-tested chemokine receptor datasets retrieved from ChEMBL and curated datasets for cannabinoid receptors. The NN model trained on the cannabinoid receptor datasets retrieved from ChEMBL was the most accurate in the receptor subtype selectivity prediction. Among NN models trained on the chemokine receptor datasets, the CXCR3 model showed the highest accuracy in differentiating the receptor subtype for a given compound dataset.

Traumatic brain injury (TBI) is a leading cause for neurological disabilities world-wide. TBI occurs most frequently among the elderly population, and elderly TBI survivors suffer from reduced recovery and poorer quality of life. The effect of age on the pathophysiology of TBI is still poorly understood. We previously established that peripherally-derived monocytes (CCR2⁺) infiltrate the injured brain and contribute to chronic TBI-induced cognitive deficits in young animals. Furthermore, age was shown to amplify monocyte infiltration acutely after injury. In the current study, we investigated the impact of age on the subchronic response of peripherally-derived monocytes (CD45hi; CCR2⁺) and their role in the development of chronic cognitive deficits. In the aged brain, there was a significant increase in the number of peripherally-derived monocytes after injury compared to young, injured animals. The infiltration rate of peripherally-derived monocytes remained elevated subchronically and corresponded with enhanced expression of CCR2 chemotactic ligands. Interestingly, the myeloid cell populations observed in injured aged brains had impaired anti-inflammatory responses compared to those in young animals. Additionally, in the aged animals, there was an expansion of the blood CCR2⁺ monocyte population after injury that was not present in the young animals. Importantly, knocking out CCR2 to inhibit infiltration of peripherally-derived monocytes prevented chronic TBI-induced spatial memory deficits in the aged mice. Altogether, these results demonstrate the critical effects of age on the peripherally-derived monocyte response during the progression of TBI pathophysiology.

Atherosclerosis is driven by a diverse range of cellular and molecular processes. In the present study, we sought to better understand how statins mitigate proatherogenic inflammation. 48 male New Zealand rabbits were divided into eight groups, each including 6 animals. The control groups received normal chow for 90 and 120 days. Three groups underwent a hypercholesterolemic diet (HCD) for 30, 60, and 90 days. Another three groups underwent HCD for 3 months, followed by normal chow for one month, with or without rosuvastatin or fluvastatin. The cytokine and chemokine expressions were assessed in the samples of thoracic and abdominal aorta. Rosuvastatin significantly reduced MYD88, CCL4, CCL20, CCR2, TNF-α, IFN-β, IL-1b, IL-2, IL-4, IL-8, and IL-10, both in the thoracic and abdominal aorta. Fluvastatin also downregulated MYD88, CCR2, IFN-β, IFN-γ, IL-1b, IL-2, IL-4, and IL-10 in both aortic segments. Rosuvastatin curtailed the expression of CCL4, IFN-β, IL-2, IL-4, and IL-10 more effectively than fluvastatin in both types of tissue. MYD88, TNF-α, IL-1b, and IL-8 showed a stronger downregulation with rosuvastatin compared to fluvastatin only in the thoracic aorta. The CCL20 and CCR2 levels reduced more extensively with rosuvastatin treatment only in abdominal aortic tissue. In conclusion, statin therapy can halt proatherogenic inflammation in hyperlipidemic animals. Rosuvastatin may be more effective in downregulating MYD88 in atherosclerotic thoracic aortas.

C-C motif chemokine ligand 2 (CCL2) is a member of the monocyte chemokine protein family, which binds to its receptor CCR2 to induce monocyte infiltration and mediate inflammation. The CCL2/CCR2 signaling pathway participates in the transduction of neuroinflammatory information between all types of cells in the central nervous system. Animal studies and clinical trials have shown that CCL2/CCR2 mediate the pathological process of ischemic stroke, and a higher CCL2 level in serum is associated with a higher risk of any form of stroke. In the acute phase of cerebral ischemia-reperfusion, the expression of CCL2/CCR2 is increased in the ischemic penumbra, which promotes neuroinflammation and enhances brain injury. In the later phase, it participates in the migration of neuroblasts to the ischemic area and promotes the recovery of neurological function. CCL2/CCR2 gene knockout or activity inhibition can reduce the nerve inflammation and brain injury induced by cerebral ischemia-reperfusion, suggesting that the development of drugs regulating the activity of the CCL2/CCR2 signaling pathway could be used to prevent and treat the cell injury in the acute phase and promote the recovery of neurological function in the chronic phase in ischemic stroke patients. [ABSTRACT FROM AUTHOR]

Chemokines and their receptors regulate the migration of immune cells and the dissemination of cancer cells. CCR1, CCR2, CCR3, and CCR5 all belong to a single protein homology cluster and respond to the same inflammatory chemokines. We previously reported that CCR1 and CCR2B are induced upon Epstein-Barr virus (EBV) infection of B cells in vitro. EBV is present in almost all cases of endemic Burkitt lymphoma (BL); however, the contribution of EBV in the pathogenesis of the disease is not fully understood. Here, we analyzed the relation of the expression of CCR1, CCR2, CCR3, and CCR5, the EBV DNA load and expression of EBV latent genes in nine EBV-carrying and four EBV-negative BL cell lines. We revealed that CCR1 is expressed at high mRNA and protein levels in two CD10-negative BL cell lines with co-expression of the EBV latent genes EBNA2, LMP1, and LMP2. Low levels of CCR2 transcripts were found in three BL cell lines. CCR3 and CCR5 transcripts were hardly detectable. Our data suggest that in vivo, CCR1 may be involved in the dissemination of BL cells and in the selection of BL cells with restricted EBV gene expression programs. [ABSTRACT FROM AUTHOR]

Acute respiratory distress syndrome (ARDS) consists of uncontrolled inflammation that causes hypoxemia and reduced lung compliance. Since it is a complex process, not all details have been elucidated yet. In a well-controlled experimental murine model of lipopolysaccharide (LPS)-induced ARDS, the activity and viability of macrophages and neutrophils dictate the beginning and end phases of lung inflammation. C-C chemokine receptor type 2 (CCR2) is a critical chemokine receptor that mediates monocyte/macrophage activation and recruitment to the tissues. Here, we used CCR2-deficient mice to explore mechanisms that control lung inflammation in LPS-induced ARDS. CCR2−/− mice presented higher total numbers of pulmonary leukocytes at the peak of inflammation as compared to CCR2+/+ mice, mainly by enhanced influx of neutrophils, whereas we observed two to six-fold lower monocyte or interstitial macrophage numbers in the CCR2−/−. Nevertheless, the time needed to control the inflammation was comparable between CCR2+/+ and CCR2−/−. Interestingly, CCR2−/− mice presented higher numbers and increased proliferative rates of alveolar macrophages from day 3, with a more pronounced M2 profile, associated with transforming growth factor (TGF)-β and C-C chemokine ligand (CCL)22 production, decreased inducible nitric oxide synthase (Nos2), interleukin (IL)-1β and IL-12b mRNA expression and increased mannose receptor type 1 (Mrc1) mRNA and CD206 protein expression. Depletion of alveolar macrophages significantly delayed recovery from the inflammatory insult. Thus, our work shows that the lower number of infiltrating monocytes in CCR2−/− is partially compensated by increased proliferation of resident alveolar macrophages during the inflammation control of experimental ARDS.

Chemokines and their receptors regulate the migration of immune cells and the dissemination of cancer cells. CCR1, CCR2, CCR3, and CCR5 all belong to a single protein homology cluster and respond to the same inflammatory chemokines. We previously reported that CCR1 and CCR2B are induced upon Epstein-Barr virus (EBV) infection of B cells in vitro. EBV is present in almost all cases of endemic Burkitt lymphoma (BL); however, the contribution of EBV in the pathogenesis of the disease is not fully understood. Here, we analyzed the relation of the expression of CCR1, CCR2, CCR3, and CCR5, the EBV DNA load and expression of EBV latent genes in nine EBV-carrying and four EBV-negative BL cell lines. We revealed that CCR1 is expressed at high mRNA and protein levels in two CD10-negative BL cell lines with co-expression of the EBV latent genes EBNA2, LMP1, and LMP2. Low levels of CCR2 transcripts were found in three BL cell lines. CCR3 and CCR5 transcripts were hardly detectable. Our data suggest that in vivo, CCR1 may be involved in the dissemination of BL cells and in the selection of BL cells with restricted EBV gene expression programs.

C-C motif chemokine ligand 2 (CCL2) is a member of the monocyte chemokine protein family, which binds to its receptor CCR2 to induce monocyte infiltration and mediate inflammation. The CCL2/CCR2 signaling pathway participates in the transduction of neuroinflammatory information between all types of cells in the central nervous system. Animal studies and clinical trials have shown that CCL2/CCR2 mediate the pathological process of ischemic stroke, and a higher CCL2 level in serum is associated with a higher risk of any form of stroke. In the acute phase of cerebral ischemia-reperfusion, the expression of CCL2/CCR2 is increased in the ischemic penumbra, which promotes neuroinflammation and enhances brain injury. In the later phase, it participates in the migration of neuroblasts to the ischemic area and promotes the recovery of neurological function. CCL2/CCR2 gene knockout or activity inhibition can reduce the nerve inflammation and brain injury induced by cerebral ischemia-reperfusion, suggesting that the development of drugs regulating the activity of the CCL2/CCR2 signaling pathway could be used to prevent and treat the cell injury in the acute phase and promote the recovery of neurological function in the chronic phase in ischemic stroke patients.

Monocytes are known to be implicated in the pathogenesis of systemic sclerosis (SSc), as they exert prominent migratory, adhesive, and chemotactic properties. The aim of our study was to characterize the surface expression of adhesion/chemotactic molecules (CD62L, CD11b, CCR2, CCR5) on the SSc monocytes and determine correlations with the clinical presentation of SSc. We included 38 SSc patients and 36 healthy age-and sex-matched controls. Isolated monocytes, as well as in vitro serum-treated monocytes, were analyzed by flow cytometry; additionally, soluble CD62L was measured in serum. We found increased soluble CD62L in the SSc serum samples and increased CD62L on the surface of the SSc monocytes in the in the same set of patients. Among samples with determined SSc-specific autoantibodies, the surface CD62L was the lowest in patients positive for anti-PM/Scl autoantibodies and the highest in patients with anti-topoisomerase I autoantibodies (ATA). The treatment of isolated healthy monocytes with ATA-positive SSc serum resulted in increased surface CD62L expression. Moreover, surface CCR5 was reduced on the monocytes from SSc patients with interstitial lung disease but also, along with CCR2, negatively correlated with the use of analgesics/anti-inflammatory drugs and immunosuppressants. In conclusion, increased CD62L on SSc monocytes, particularly in ATA-positive patients, provides new insights into the pathogenesis of SSc and suggests CD62L as a potential therapeutic target.

The CD73 pathway is an important anti-inflammatory mechanism in various disease settings. Observations in mouse models suggested that CD73 might have a protective role in kidney damage; however, no direct evidence of its role in human kidney disease has been described to date. Here, we hypothesized that podocyte injury in human kidney diseases alters CD73 expression that may facilitate the diagnosis of podocytopathies. We assessed the expression of CD73 and one of its functionally important targets, the C-C chemokine receptor type 2 (CCR2), in podocytes from kidney biopsies of 39 patients with podocytopathy (including focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD), membranous glomerulonephritis (MGN) and amyloidosis) and a control group. Podocyte CD73 expression in each of the disease groups was significantly increased in comparison to controls (p < 0.001–p < 0.0001). Moreover, there was a marked negative correlation between CD73 and CCR2 expression, as confirmed by immunohistochemistry and immunofluorescence (Pearson r = −0.5068, p = 0.0031; Pearson r = −0.4705, p = 0.0313, respectively), thus suggesting a protective role of CD73 in kidney injury. Finally, we identify CD73 as a novel potential diagnostic marker of human podocytopathies, particularly of MCD that has been notorious for the lack of pathological features recognizable by light microscopy and immunohistochemistry.

C-C motif ligand 2 (CCL2) was originally reported as a chemical mediator attracting mononuclear cells to inflammatory tissue. Many studies have reported that CCL2 can directly activate cancer cells through a variety of mechanisms. CCL2 can also promote cancer progression indirectly through increasing the recruitment of tumor-associated macrophages into the tumor microenvironment. The role of CCL2 in cancer progression has gradually been understood, and various preclinical cancer models elucidate that CCL2 and its receptor C-C chemokine receptor 2 (CCR2) are attractive targets for intervention in cancer development. However, clinically available drugs that regulate the CCL2–CCR2 axis as anticancer agents are not available at this time. The complete elucidation of not only the oncological but also the physiological functions of the CCL2–CCR2 axis is required for achieving a satisfactory effect of the CCL2–CCR2 axis-targeted therapy.

Although intravenous administration of mesenchymal stem cells (MSCs) is effective for experimental stroke, low engraftment and the limited functional capacity of transplanted cells are critical hurdles for clinical applications. C–C motif chemokine ligand 2 (CCL2) is associated with neurological repair after stroke and delivery of various cells into the brain via CCL2/CCR2 (CCL2 receptor) interaction. In this study, after CCL2-overexpressing human umbilical cord-derived MSCs (hUC-MSCs) were intravenously transplanted with mannitol in rats with middle cerebral arterial occlusion, we compared the differences between four different treatment groups: mannitol + CCL2-overexpressing hUC-MSCs (CCL2-MSC), mannitol + naïve hUC-MSCs (M-MSC), mannitol only, and control. At four-weeks post-transplantation, the CCL2-MSC group showed significantly better functional recovery and smaller stroke volume relative to the other groups. Additionally, we observed upregulated levels of CCR2 in acute ischemic brain and the increase of migrated stem cells into these areas in the CCL2-MSC group relative to the M-MSC. Moreover, the CCL2-MSC group displayed increased angiogenesis and endogenous neurogenesis, decreased neuro-inflammation but with increased healing-process inflammatory cells relative to other groups. These findings indicated that CCL2-overexpressing hUC-MSCs showed better functional recovery relative to naïve hUC-MSCs according to the increased migration of these cells into brain areas of higher CCR2 expression, thereby promoting subsequent endogenous brain repair.

Monocytes are known to be implicated in the pathogenesis of systemic sclerosis (SSc), as they exert prominent migratory, adhesive, and chemotactic properties. The aim of our study was to characterize the surface expression of adhesion/chemotactic molecules (CD62L, CD11b, CCR2, CCR5) on the SSc monocytes and determine correlations with the clinical presentation of SSc. We included 38 SSc patients and 36 healthy age-and sex-matched controls. Isolated monocytes, as well as in vitro serum-treated monocytes, were analyzed by flow cytometry; additionally, soluble CD62L was measured in serum. We found increased soluble CD62L in the SSc serum samples and increased CD62L on the surface of the SSc monocytes in the in the same set of patients. Among samples with determined SSc-specific autoantibodies, the surface CD62L was the lowest in patients positive for anti-PM/Scl autoantibodies and the highest in patients with anti-topoisomerase I autoantibodies (ATA). The treatment of isolated healthy monocytes with ATA-positive SSc serum resulted in increased surface CD62L expression. Moreover, surface CCR5 was reduced on the monocytes from SSc patients with interstitial lung disease but also, along with CCR2, negatively correlated with the use of analgesics/anti-inflammatory drugs and immunosuppressants. In conclusion, increased CD62L on SSc monocytes, particularly in ATA-positive patients, provides new insights into the pathogenesis of SSc and suggests CD62L as a potential therapeutic target. [ABSTRACT FROM AUTHOR]

The CD73 pathway is an important anti-inflammatory mechanism in various disease settings. Observations in mouse models suggested that CD73 might have a protective role in kidney damage; however, no direct evidence of its role in human kidney disease has been described to date. Here, we hypothesized that podocyte injury in human kidney diseases alters CD73 expression that may facilitate the diagnosis of podocytopathies. We assessed the expression of CD73 and one of its functionally important targets, the C-C chemokine receptor type 2 (CCR2), in podocytes from kidney biopsies of 39 patients with podocytopathy (including focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD), membranous glomerulonephritis (MGN) and amyloidosis) and a control group. Podocyte CD73 expression in each of the disease groups was significantly increased in comparison to controls (p < 0.001–p < 0.0001). Moreover, there was a marked negative correlation between CD73 and CCR2 expression, as confirmed by immunohistochemistry and immunofluorescence (Pearson r = −0.5068, p = 0.0031; Pearson r = −0.4705, p = 0.0313, respectively), thus suggesting a protective role of CD73 in kidney injury. Finally, we identify CD73 as a novel potential diagnostic marker of human podocytopathies, particularly of MCD that has been notorious for the lack of pathological features recognizable by light microscopy and immunohistochemistry. [ABSTRACT FROM AUTHOR]

C-C motif ligand 2 (CCL2) was originally reported as a chemical mediator attracting mononuclear cells to inflammatory tissue. Many studies have reported that CCL2 can directly activate cancer cells through a variety of mechanisms. CCL2 can also promote cancer progression indirectly through increasing the recruitment of tumor-associated macrophages into the tumor microenvironment. The role of CCL2 in cancer progression has gradually been understood, and various preclinical cancer models elucidate that CCL2 and its receptor C-C chemokine receptor 2 (CCR2) are attractive targets for intervention in cancer development. However, clinically available drugs that regulate the CCL2–CCR2 axis as anticancer agents are not available at this time. The complete elucidation of not only the oncological but also the physiological functions of the CCL2–CCR2 axis is required for achieving a satisfactory effect of the CCL2–CCR2 axis-targeted therapy. [ABSTRACT FROM AUTHOR]

Although intravenous administration of mesenchymal stem cells (MSCs) is effective for experimental stroke, low engraftment and the limited functional capacity of transplanted cells are critical hurdles for clinical applications. C–C motif chemokine ligand 2 (CCL2) is associated with neurological repair after stroke and delivery of various cells into the brain via CCL2/CCR2 (CCL2 receptor) interaction. In this study, after CCL2-overexpressing human umbilical cord-derived MSCs (hUC-MSCs) were intravenously transplanted with mannitol in rats with middle cerebral arterial occlusion, we compared the differences between four different treatment groups: mannitol + CCL2-overexpressing hUC-MSCs (CCL2-MSC), mannitol + naïve hUC-MSCs (M-MSC), mannitol only, and control. At four-weeks post-transplantation, the CCL2-MSC group showed significantly better functional recovery and smaller stroke volume relative to the other groups. Additionally, we observed upregulated levels of CCR2 in acute ischemic brain and the increase of migrated stem cells into these areas in the CCL2-MSC group relative to the M-MSC. Moreover, the CCL2-MSC group displayed increased angiogenesis and endogenous neurogenesis, decreased neuro-inflammation but with increased healing-process inflammatory cells relative to other groups. These findings indicated that CCL2-overexpressing hUC-MSCs showed better functional recovery relative to naïve hUC-MSCs according to the increased migration of these cells into brain areas of higher CCR2 expression, thereby promoting subsequent endogenous brain repair. [ABSTRACT FROM AUTHOR]