C-C motif chemokine ligand 2 promotes myogenesis of myoblasts via the AKT-mTOR pathway

Plasminogen and plasmin can bind to human T cells and generate truncated CCL21 that increases dendritic cell chemotactic responses

Muscle mass decreases with aging, while the C-C motif chemokine ligand 2 (CCL2) increases with aging. In our previous study, CCL2 positively affects in vitro myogenesis. In this context, CCL2 can be considered a potential aging-promoting factor. To further confirm the relationship between muscle and CCL2, we sought to establish the role of CCL2 in vivo and in humans. It was divided into Dimethyl Sulfoxide (DMSO) control, dexamethasone (Dexa) intraperitoneal treatment group, and Dexa with the CCL2 treatment group. As a result, grip power and exercise endurance were reduced in the Dexa treatment group compared to the control group but recovered with the CCL2 treatment. In muscle mass, there was no significant difference in mass between groups. We examined the cross-sectional area distribution (CSA) with the tibialis anterior muscle. The Dexa treatment group was distributed between CSA 1000-3000 µm² and was left-shifted. However, the Dexa and CCL2 group was similar or slightly higher than the DMSO group; it was right-shifted and distributed in the 2000-5000 µm². In humans, the median value was 303.8 pg/ml in the no sarcopenia group and 321.7 pg/ml in the sarcopenia group. Subsequently, the CCL2 level was checked by dividing the groups into whether there was sarcopenia, low mass, low strength, or low speed. The CCL2 level was statistically significantly higher in the group showing low speed. In conclusion, CCL2 promotes myogenesis recovery, muscle strength, and muscle performance in vivo and has clinical relevance for muscle performance in humans. Disclosure E.Hong: None. E.Ha: None. J.Lee: None. Y.Choi: None. K.Lee: None. J.Won: None. M.Kwak: None. Funding Ministry of Education, Republic of Korea (2020R1I1A3073230)

Sickness behavior defines the endocrine, autonomic, behavioral, and metabolic responses associated with infection. While inflammatory responses were suggested to be instrumental in the loss of appetite and body weight, the molecular underpinning remains unknown. Here, we show that systemic or central lipopolysaccharide (LPS) injection results in specific hypothalamic changes characterized by a precocious increase in the chemokine ligand 2 (CCL2) followed by an increase in pro-inflammatory cytokines and a decrease in the orexigenic neuropeptide melanin-concentrating hormone (MCH). We therefore hypothesized that CCL2 could be the central relay for the loss in body weight induced by the inflammatory signal LPS. We find that central delivery of CCL2 promotes neuroinflammation and the decrease in MCH and body weight. MCH neurons express CCL2 receptor and respond to CCL2 by decreasing both electrical activity and MCH release. Pharmacological or genetic inhibition of CCL2 signaling opposes the response to LPS at both molecular and physiologic levels. We conclude that CCL2 signaling onto MCH neurons represents a core mechanism that relays peripheral inflammation to sickness behavior.

Porcine embryos are used for a variety of applications. However, the maturation rate in vitro remains low, and novel in vitro maturation (IVM) techniques that facilitate the collection of mature oocytes are necessary. C-C motif chemokine ligand 2 (CCL2) is a key periovulatory chemokine present in cumulus-oocyte complexes (COCs). We aimed to examine the effects of CCL2 supplementation during IVM on oocyte maturation and embryonic development. The CCL2 concentration was significantly higher in porcine follicular fluid (pFF) derived from follicles >8 mm in size than in pFF derived from smaller follicles. There was a significant increase in CCL2 mRNA levels in all follicular cells after IVM compared with that before IVM. We analyzed the localization of CCL2 and its receptor, the CCL2 receptor, in follicular cells. During IVM, different concentrations of CCL2 were added to COCs cultured in a maturation medium. After IVM, the group treated with 100 ng/mL CCL2 showed significantly higher metaphase II rates than the control group. All CCL2-treatment groups showed a significant increase in intracellular glutathione levels and a significant decrease in reactive oxygen species levels, compared to the control. In CCs treated with 100 ng/mL CCL2, the mRNA levels of BAX, CASP3, and NPR2 were significantly decreased. Furthermore, the mRNA levels of SOD1, SOD2, and CD44 were significantly increased. In oocytes treated with 10 ng/mL CCL2, mRNA levels of BAX and CASP3 were significantly decreased, whereas, NRF2 and NPM2 were significantly increased. ERK1 exhibited significantly increased mRNA expression in both CCs and oocytes treated with 10 ng/mL CCL2. The protein expression ratio of phosphorylated ERK1/2 to total ERK1/2 was significantly increased in CCs treated with 10 ng/mL CCL2. After parthenogenetic activation, cleavage rates were significantly improved in the 100 ng/mL CCL2 treatment group, and blastocyst formation rates were significantly enhanced in the 10 ng/mL CCL2 treatment group. Overall, our results suggest that IVM medium along with CCL2 improves porcine oocyte maturation and the development of parthenogenetically-activated embryos.

Transcription factor tonicity-responsive enhancer-binding protein (TonEBP/NFAT5) is critical for osmo-adaptation and extracellular matrix homeostasis of nucleus pulposus (NP) cells in their hypertonic tissue niche. Recent studies implicate TonEBP signaling in inflammatory disease and rheumatoid arthritis pathogenesis. However, broader functions of TonEBP in the disc remain unknown. RNA sequencing was performed on NP cells with TonEBP knockdown under hypertonic conditions. 1140 TonEBP-dependent genes were identified and categorized using Ingenuity Pathway Analysis. Bioinformatic analysis showed enrichment of matrix homeostasis and cytokine/chemokine signaling pathways. C-C motif chemokine ligand 2 (CCL2), interleukin 6 (IL6), tumor necrosis factor (TNF), and nitric oxide synthase 2 (NOS2) were studied further. Knockdown experiments showed that TonEBP was necessary to maintain expression levels of these genes. Gain- and loss-of-function experiments and site-directed mutagenesis demonstrated that TonEBP binding to a specific site in the CCL2 promoter is required for hypertonic inducibility. Despite inhibition by dominant-negative TonEBP, IL6 and NOS2 promoters were not hypertonicity-inducible. Whole-disc response to hypertonicity was studied in an ex vivo organ culture model, using wild-type and haploinsufficient TonEBP mice. Pro-inflammatory targets were induced by hypertonicity in discs from wild-type but not TonEBP-haploinsufficient mice. Mechanistically, NF-κB activity increased with hypertonicity and was necessary for hypertonic induction of target genes IL6, TNF, and NOS2 but not CCL2 Although TonEBP maintains transcription of genes traditionally considered pro-inflammatory, it is important to note that some of these genes also serve anabolic and pro-survival roles. Therefore, in NP cells, this phenomenon may reflect a physiological adaptation to diurnal osmotic loading of the intervertebral disc.

Simple SummaryCancer cells and mesenchymal stem cells (MSCs) secrete C-C motif chemokine ligand 2 (CCL2), a small protein that attracts tumor-associated macrophages (TAMs), which promotes malignant progression, such as drug resistance and metastasis. In addition, MSCs can also be recruited by CCL2; thus, a local milieu consisting of tumor cells, MSCs, and TAMs can promote tumor progression via a CCL2-dependent paracrine. The aim of the current study was to examine the functions of endogenous CCL2 of MSCs in cancer biology. Using a genetic engineering technique, we blocked the CCL2 expression in murine bone marrow-derived MSCs (CCL2 KO MSCs) and analyzed the effects on cancer progression. We found that CCL2 KO MSCs showed anti-tumor function when injected with murine prostate cancer cells into mice. The inhibitory effect was associated with an increase of CD45+CD11b+ mononuclear myeloid cells in tumors.Background: MSCs are known to secrete abundant CCL2, which plays a crucial role in recruiting TAMs, promoting tumor progression. It is important to know whether disrupting MSC-derived CCL2 affects tumor growth. Methods: Murine bone marrow-derived MSCs were characterized by their surface markers and differentiation abilities. Proliferation and migration assays were performed in order to evaluate the functions of MSCs on cancer cells. CCL2 expression in MSCs was reduced by small interfering RNA (siRNA) or completely disrupted by CRISPR/Cas9 knockout (KO) approaches. An immune-competent syngeneic murine model of prostate cancer was applied in order to assess the role of tumor cell- and MSC-derived CCL2. The tumor microenvironment was analyzed to monitor the immune profile. Results: We confirmed that tumor cell-derived CCL2 was crucial for tumor growth and MSCs migration. CCL2 KO MSCs inhibited the migration of the monocyte/macrophage but not the proliferation of tumor cells in vitro. However, the mice co-injected with tumor cells and CCL2 KO MSCs exhibited anti-tumor effects when compared with those given tumor cell alone and with control MSCs, partly due to increased infiltration of CD45+CD11b+Ly6G− mononuclear myeloid cells. Conclusions: Disruption of MSC-derived CCL2 enhances anti-tumor functions in an immune-competent syngeneic mouse model for prostate cancer.

Up to 45% of breast cancer patients experience a condition called Skeletal Muscle Wasting (SMW). SMW causes significant progressive muscle loss, weakness, and fatigue. SMW in patients adversely affects quality of life during and results in a severely reduced ability of patients to tolerate chemotherapeutic drugs. Chemotherapy itself also exacerbates SMW in patients. There are currently no effective therapies for SMW. This condition is rarely reported in patient records and is often overlooked in patients with a high body mass index. Although this condition is associated with significantly lower survival rates compared to patients with relatively normal muscle mass, we do not yet understand the molecular mechanism by which it occurs in breast cancer patients. In this study, we investigate the role that CCL2 plays in breast cancer and chemotherapy induced SMW. CCL2 is a chemokine that regulates recruitment of immune cells to sites of injury and inflammation. CCL2 is overexpressed in breast cancer and SMW has been linked to elevated levels of CCL2. CCL2 overexpression is also associated with high mortality rates in breast cancer patients. To investigate the role of CCL2 in muscle wasting we treated C2C12 mouse muscle cells with increasing concentrations of CCL2. This led to increased expression of markers of muscle degradation, MuRF-1 and Atrogin-1, with reduced muscle cell proliferation and muscle cell size. This indicates that high levels of CCL2 cause muscle degradation. Using an MDA-MB-231 model of breast cancer, we show that CCL2 knockdown in the primary breast tumor decreases the expression of muscle degradation markers. Further experiments using the 4T1 mammary tumor model show that mice in which CCL2 was knocked down exhibited greater grip strength than those mice in which CCL2 levels remained unaltered. Therefore, CCL2 knockdown reduces muscle degradation and increases grip strength in a mouse model of breast cancer. We also investigated the effect of chemotherapy on SMW. Preliminary in vitro data shows increased expression of CCL2 in response to chemotherapy treatment, while in vivo experiments using the 4T1 breast tumor model indicate that chemotherapeutic treatment also significantly reduces grip strength in mice. Our findings suggest that we can improve patient survival rates and quality of life by developing therapies to combat muscle loss during and after treatment. Understanding the mechanism of muscle wasting is necessary to provide insight into novel, targeted therapeutics to reduce SMW and enhance effectiveness of anti-cancer drugs. Citation Format: Nadia Alissa, Wei Bin Fang, Gage Brummer, Marcela Mitchell, John Thyfault, Paige Geiger, Nikki Cheng. The chemokine C-C motif ligand 2 (CCL2) plays an important role in skeletal muscle wasting associated with breast cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3852.

Deletion of C-C Motif Chemokine Ligand 5 Worsens Invariant Natural Killer T-Cell-Mediated Hepatitis via Compensatory Up-regulation of CXCR2-Related Chemokine Activity.

The last decade has witnessed revolutionary advances taken in immunotherapy for various malignant tumors. However, immune-related molecules and their characteristics in the prediction of clinical outcomes and immunotherapy response in clear cell renal cell carcinoma (ccRCC) remain largely unclear. C-C Motif Chemokine Ligand 4 (CCL4) was extracted from the intersection analysis of common differentially expressed genes (DEGs) of four microarray datasets from the Gene Expression Omnibus database and immune-related gene lists in the ImmPort database using Cytoscape plug-ins and univariate Cox regression analysis. Subsequential analysis revealed that CCL4 was highly expressed in ccRCC patients, and positively correlated with multiple clinicopathological characteristics, such as grade, stage and metastasis, while negatively with overall survival (OS). We performed gene set enrichment analysis (GSEA) and gene set variant analysis (GSVA) with gene sets coexpressed with CCL4, and observed that gene sets positively related to CCL4 were enriched in tumor proliferation and immune-related pathways while metabolic activities in the negatively one. To further explore the correlation between CCL4 and immune-related biological process, the CIBERSORT algorithm, ESTIMATE method, and tumor mutational burden (TMB) score were employed to evaluate the tumor microenvironment (TME) characteristics of each sample and confirmed that high CCL4 expression might give rise to high immune cell infiltration. Moreover, correlation analysis revealed that CCL4 was positively correlated with common immune checkpoint genes, such as programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA4), and lymphocyte activating 3 (LAG3). Overall, this study demonstrated that CCL4 might serve as a potential immune-related prognostic biomarker to predict clinical outcomes and immunotherapy response in ccRCC. Moreover, CCL4 might contribute to TME modulation, indicating the mechanism CCL4 involved in tumor proliferation and metastasis, which could provide novel therapeutic perceptions for ccRCC patients.

BackgroundTraumatic brain injury (TBI) causes axon tearing and synapse degradation, resulting in multiple neurological dysfunctions and exacerbation of early neurodegeneration; the repair of axonal and synaptic structures is critical for restoring neuronal function. C-C Motif Chemokine Ligand 5 (CCL5) shows many neuroprotective activities.MethodA close-head weight-drop system was used to induce mild brain trauma in C57BL/6 (wild-type, WT) and CCL5 knockout (CCL5-KO) mice. The mNSS score, rotarod, beam walking, and sticker removal tests were used to assay neurological function after mTBI in different groups of mice. The restoration of motor and sensory functions was impaired in CCL5-KO mice after one month of injury, with swelling of axons and synapses from Golgi staining and reduced synaptic proteins-synaptophysin and PSD95. Administration of recombinant CCL5 (Pre-treatment: 300 pg/g once before injury; or post-treatment: 30 pg/g every 2 days, since 3 days after injury for 1 month) through intranasal delivery into mouse brain improved the motor and sensory neurological dysfunctions in CCL5-KO TBI mice.ResultsProteomic analysis using LC-MS/MS identified that the “Nervous system development and function”-related proteins, including axonogenesis, synaptogenesis, and myelination signaling pathways, were reduced in injured cortex of CCL5-KO mice; both pre-treatment and post-treatment with CCL5 augmented those pathways. Immunostaining and western blot analysis confirmed axonogenesis and synaptogenesis related Semaphorin, Ephrin, p70S6/mTOR signaling, and myelination-related Neuregulin/ErbB and FGF/FAK signaling pathways were up-regulated in the cortical tissue by CCL5 after brain injury. We also noticed cortex redevelopment after long-term administration of CCL5 after brain injury with increased Reelin positive Cajal-Rerzius Cells and CXCR4 expression. CCL5 enhanced the growth of cone filopodia in a primary neuron culture system; blocking CCL5’s receptor CCR5 by Maraviroc reduced the intensity of filopodia in growth cone and also CCL5 mediated mTOR and Rho signalling activation. Inhibiting mTOR and Rho signaling abolished CCL5 induced growth cone formation.ConclusionsCCL5 plays a critical role in starting the intrinsic neuronal regeneration system following TBI, which includes growth cone formation, axonogenesis and synaptogensis, remyelination, and the subsequent proper wiring of cortical circuits. Our study underscores the potential of CCL5 as a robust therapeutic stratagem in treating axonal injury and degeneration during the chronic phase after mild brain injury.Graphical

C-C motif chemokine ligand 18 (CCL18) is overexpressed in the microenvironment of tumors, promotes invasion and metastasis and is thus important for the therapeutic outcome of many tumor entities. The Gs-coupled seven-transmembrane receptor GPR30 is known as both a CCL18 and an estrogen receptor; its activation by estradiol leads to a transactivation of membrane-tethered pro-heparin-binding EGF-like growth factor and the MAPK/ERK pathway. We examined whether this signaling pathway remains the same under CCL18 stimulation, as opposed to estradiol stimulation. We investigated the effects of CCL18 on the lung cancer cell line A549, that show low GPR30 expression and the breast cancer cell lines MCF-7, that has high GPR30 expression and MDA-MB-231. These cells were stimulated in different media with CCL18 and then analyzed by qPCR, In-Cell Western®, western blot and ELISA. Many similarities on the effect of CCL18 on the already known estradiol-activated signaling pathway via the G protein-coupled estrogen receptor GPR30 were identified. GPR30 is involved in the expression of matrix metalloproteinases (MMPs), which may play a role in the transactivation of ERK-1/-2 via the cleavage of membrane-bound HB-EGF, via Src-related tyrosine kinases and Gβγ-subunits. With increasing CCL18 concentration, the expression of MMP7 decreased in A549 cells. With decreasing estrogen content of the medium, there was an increasing effect of CCL18 on the inhibition of the relative expression of MMP7. Inhibition of GPR30 with G15 also resulted in a decrease in the relative expression of MMP7, irrespective of the subsequent stimulation with CCL18. This is a rather unexpected result, because the estrogen estradiol and CCL18 both activate GPR30. MCF-7 cells which express more GPR30 did not show any dependence of the relative MMP7 expression on CCL18 except in estrogen-free FCS medium. CCL18 induced an increased relative ERK activation in In-Cell western (ICW) at A549 cells. Stimulation with CCL18 caused decreased ERK activation with simultaneous inhibition of adenylate cyclase in MCF-7. However, stimulation with CCL18 and simultaneous inhibition of cyclooxygenase in MCF-7 resulted in increased ERK activation. In A549, stimulation with CCL18 and co-incubation with dbcAMP resulted in decreased ERK activation in both ICW and Western blot. In summary, the Gs-coupled receptor GPR30 plays an important role in the signaling pathway of CCL18. CCL18 and estradiol may not lead to the same signaling pathway after activating GPR30.

The skeletal muscle is an endocrine organ that produces proteins and peptides, collectively termed as myokines. The temperature of skeletal muscles varies during exercise and/or with changes in ambient temperature. However, whether myokine secretion is regulated by heat stimulation is unclear. Thus, we aimed to explore the effects of environmental heat stimulation on myokine secretion. We initially investigated the secretome of C2C12 myotubes and identified several novel heat-responsive myokines. The concentration of C-C motif chemokine ligand 5 (CCL5) dramatically decreased by 0.3-fold in response to heat stress. After 3 h heat stimulation of C2C12 cells, the expression of heat shock protein 70 was induced, and the gene expression and secretion of CCL5 was significantly attenuated in C2C12 cells. We then examined the effects of acute heat stress on serum CCL5 levels in mice and Ccl5 gene expression in skeletal muscles. Mice were maintained at 23°C, exposed to 45°C for 30 min, and then returned to the 23°C chamber for recovery. The expression of Ccl5 in the skeletal muscle significantly decreased after 3 h of recovery. Serum CCL5 levels increased by approximately 1.9-fold after 30 min of heat exposure and then significantly decreased by approximately 0.7-fold after 23 h of recovery. This study suggests that heat stimulation decreases CCL5 secretion from the skeletal muscle in vitro and in vivo. Given its fundamental role in inflammation by recruiting several immune cells, CCL5 has a potential role in controlling inflammatory responses in the body after heat stimulation.

Novel minimally invasive strategies are needed to obtain robust bone healing in complex fractures and bone defects in the elderly population. Local cell therapy is one potential option for future treatment. Mesenchymal stromal cells (MSCs) are not only involved in osteogenesis but also help direct the recruitment of macrophages during bone regeneration via MSC-macrophage crosstalk. The C-C motif chemokine ligand 2 (CCL2) is an inflammatory chemokine that is associated with the migration of macrophages and MSCs during inflammation. This study investigated the use of CCL2 as a therapeutic target for local cell therapy. MSCs and macrophages were isolated from 10 to 12week-old BALB/c male mice. Genetically modified CCL2 over-expressing MSCs were produced using murine CCL2-secreting pCDH-CMV-mCCL2-copGFP expressing lentivirus vector. Osteogenic differentiation assays were performed using MSCs with or without macrophages in co-culture. Cell migration assays were also performed. MSCs transfected with murine CCL2-secreting pCDH-CMV-mCCL2-copGFP expressing lentivirus vector showed higher levels of CCL2 secretion compared to unaltered MSCs (p < 0.05). Genetic manipulation did not affect cell proliferation. CCL2 did not affect the osteogenic ability of MSCs alone. However, acute (1day) but not sustained (7days) stimulation with CCL2 increased the alizarin red-positive area when MSCs were co-cultured with macrophages (p < 0.001). Both recombinant CCL2 (p < 0.05) and CCL2 released from MSCs (p < 0.05) facilitated macrophage migration. We demonstrated that acute CCL2 stimulation promoted subsequent osteogenesis in co-culture of MSCs and macrophages. Acute CCL2 stimulation potentially facilitates osteogenesis during the acute inflammatory phase of bone healing by directing local macrophage migration, fostering macrophage-MSC crosstalk, and subsequently, by activating or licensing of MSCs by macrophage pro-inflammatory cytokines. The combination of CCL2, MSCs, and macrophages could be a potential strategy for local cell therapy in compromised bone healing.

The last decade has witnessed revolutionary advances taken in immunotherapy for various malignant tumors. However, immune-related molecules and their characteristics in the prediction of clinical outcomes and immunotherapy response in clear cell renal cell carcinoma (ccRCC) remain largely unclear. C-C Motif Chemokine Ligand 4 (CCL4) was extracted from the intersection analysis of common differentially expressed genes (DEGs) of four microarray datasets from the Gene Expression Omnibus database and immune-related gene lists in the ImmPort database using Cytoscape plug-ins and univariate Cox regression analysis. Subsequential analysis revealed that CCL4 was highly expressed in ccRCC patients, and positively correlated with multiple clinicopathological characteristics, such as grade, stage, and metastasis, while negatively with overall survival (OS). We performed gene set enrichment analysis (GSEA) and gene set variant analysis (GSVA) with gene sets coexpressed with CCL4, and observed that gene sets positively related to CCL4 were enriched in tumor proliferation and immune-related pathways while metabolic activities in the negatively one. To further explore the correlation between CCL4 and immune-related biological process, the CIBERSORT algorithm, ESTIMATE method, and tumor mutational burden (TMB) score were employed to evaluate the tumor microenvironment (TME) characteristics of each sample and confirmed that high CCL4 expression might give rise to high immune cell infiltration. Moreover, correlation analysis revealed that CCL4 was positively correlated with common immune checkpoint genes, such as programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA4), and lymphocyte activating 3 (LAG3). Overall, this study demonstrated that CCL4 might serve as a potential immune-related prognostic biomarker to predict clinical outcomes and immunotherapy response in ccRCC. Moreover, CCL4 might contribute to TME modulation, indicating the mechanism CCL4 involved in tumor proliferation and metastasis, which could provide novel therapeutic perceptions for ccRCC patients.

Background: Tumor-associated macrophages (TAMs) dominate the malignancy of cancers by perturbing the tumor microenvironment (TME). However, the clinical implications of heterogeneous subpopulations of TAMs in clear cell renal cell carcinoma (ccRCC) remain to be elucidated.Methods: We comprehensively evaluated the prognostic implications, biological behaviors, and immunogenomics features of the C-C Motif Chemokine Ligand 5 (CCL5) expression and CCL5+ TME in vitro and in 932 real-world ccRCC patients from testing and public validation cohorts. Flow cytometry was used to examine the functional patterns of CCL5+ TAMs with TME cell-infiltrating characterizations.Results: Our results identified distinct prognostic clusters with gradual changes in clinicopathological indicators based on CCL5 expression. Knockdown of CCL5 significantly restrained cell viability, migration capabilities of ccRCC cells, and the inhibits the proliferation and chemotaxis of THP1-derived TAMs. Mechanically, down-regulation of CCL5 arrested epithelial-mesenchymal transition by modulating the PI3K/AKT pathway in ccRCC cells. In ccRCC samples with CCL5 upregulation, the proportion of CCL5+ TAMs and PD-L1+ CD68+ TAMs were prominently increased, showing a typical suppressive tumor immune microenvironment (TIME). Besides, intra-tumoral CCL5+ TAMs showed distinct pro-tumorigenic TME features characterized by exhausted CD8+ T cells and increased expression of immune checkpoints. Furthermore, elevated CCL5+ TAMs infiltration was prominently associated with a dismal prognosis for patients with ccRCC.Conclusion: In conclusion, this study first revealed the predictive value of the chemokine CCL5 on the progression and TME of ccRCC. The intra-tumoral CCL5+ TAMs could be applied to comprehensively evaluate the prognostic patterns as well as unique TME characteristics among individuals, allowing for the identification of immunophenotypes and promotion of treatment efficiency for ccRCC.