Loss of microglial Arid1a exacerbates microglial scar formation via elevated CCL5 after traumatic brain injury.

Traumatic brain injury (TBI) is an acquired insult to the brain caused by an external mechanical force, potentially resulting in temporary or permanent impairment. Microglia, the resident immune cells of the central nervous system, are activated in response to TBI, participating in tissue repair process. However, the underlying epigenetic mechanisms in microglia during TBI remain poorly understood. ARID1A (AT-Rich Interaction Domain 1 A), a pivotal subunit of the multi-protein SWI/SNF chromatin remodeling complex, has received little attention in microglia, especially in the context of brain injury. In this study, we generated a Arid1a cKO mouse line to investigate the potential roles of ARID1A in microglia in response to TBI. We found that glial scar formation was exacerbated due to increased microglial migration and a heightened inflammatory response in Arid1a cKO mice following TBI. Mechanistically, loss of ARID1A led to an up-regulation of the chemokine CCL5 in microglia upon the injury, while the CCL5-neutralizing antibody reduced migration and inflammatory response of LPS-stimulated Arid1a cKO microglia. Importantly, administration of auraptene (AUR), an inhibitor of CCL5, repressed the microglial migration and inflammatory response, as well as the glial scar formation after TBI. These findings suggest that ARID1A is critical for microglial response to injury and that AUR has a therapeutic potential for the treatment of TBI.

Downregulation of chemokine (C­C motif) ligand 5 induced by a novel 8­hydroxyquinoline derivative (91b1) suppresses tumor invasiveness in esophageal carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a particularly aggressive form of cancer with high mortality. In the present study, a novel 8­hydroxyquinoline derivative (91b1) was investigated for its anticancer activities in ESCC along with its associated mechanisms. The in vitro cytotoxic effect of 91b1 were evaluated across five ESCC cell lines using MTS assay, with cisplatin serving as a comparative standard. Changes in gene expression profile were identified by cDNA microarray and further validated by qualitative PCR and immunostaining. Additionally, protein levels of the most notably downregulated target in archival ESCC samples were also studied. 91b1 demonstrated comparable anticancer effect with cisplatin. Notably, chemokine ligand 5 (Ccl5) was identified as the most substantially downregulated gene, with its suppression at both mRNA and protein expression in ESCC cells, exhibiting a dose­dependent manner. The recombinant human protein of CCL5 enhanced the invasion of ESCC cells using the Transwell assay. The upregulation of CCL5 protein was also detected in 50% of ESCC cell lines. CCL5 was also overexpressed in 76.9% of ESCC specimens. The overall results indicated that 91b1 could effectively induce anticancer effect on ESCC cells through downregulating CCL5 expression with suppression of tumor invasion. Overall, these findings suggested that 91b1 effectively inhibited ESCC cell proliferation and tumor invasion by downregulating CCL5 expression, highlighting its potential as a therapeutic agent for ESCC treatment.

EBV-associated epithelial cancers cells promote vasculogenic mimicry formation via a secretory cross-talk with the immune microenvironment.

Background: Vasculogenic mimicry (VM) induced by Epstein-Barr virus (EBV) infection plays an important role in resistance to anti-vascular endothelial growth factor (VEGF) therapy in EBV-associated epithelial cancers; however, the interaction between VM and the immune microenvironment has not been systematically investigated. Methods: IHC and multiplex IHC analysis the relationships among tumour-associated macrophage (TAM), VM and EBV infection in EBV-associated epithelial cancer biopsies. In vitro and in vivo evidence using CRISPR-Cas9 system engineered EBV-infected epithelial cancer cells and mouse models support functional role and mechanism for M2c-like macrophages in the VM formation. The prediction of VM in the effectiveness of anti-angiogenic agent was analysed using clinical datasets. Results: EBV-associated epithelial cancer biopsies revealed that infiltration of the TAM surrounding the VM is closely associated with EBV infection. AKT/mTOR/HIF-1α pathway in EBV-infected epithelial cancer cells control the secretion of CCL5 and CSF-1, enabling the recruitment of monocytes and their differentiation into M2c macrophages which promote VM formation by MMP9. Combination of anti-angiogenesis agents and HIF-1α inhibitor caused marked decreases in CD31-positive micro-vessels, VM, and M2c-like macrophages. VM scores can be used as biomarkers to predict the efficacy of anti-angiogenic agent therapy in EBV-associated epithelial cancers. Conclusions: Our findings define a secretory cross-talk between tumour cells and the immune microenvironment in EBV-associated epithelial cancer, revealing an unexpected role of EBV in epithelial cancer cells, controlling VM formation via M2c-like macrophages.

CCL5 is essential for axonogenesis and neuronal restoration after brain injury.

BACKGROUND: Traumatic 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. METHOD: A 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. RESULTS: Proteomic 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. CONCLUSIONS: CCL5 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.

Cylindromatosis lysine 63 deubiquitinase (CYLD) suppress TLR3-mediated CCL5 expression in human renal proximal tubular epithelial cells.

BACKGROUND: One of the causes of tubulointerstitial nephritis is viral infection, with innate immune responses affecting its pathogenesis. Toll-like receptor 3 (TLR3) recognizes viral infections and acts antivirally by activating signaling to produce inflammatory cytokines/chemokines, including C-C motif chemokine ligand 5 (CCL5) and interferon-ß (IFN-ß). Although cylindromatosis lysine 63 deubiquitinase (CYLD) is known to be associated with tubulointerstitial nephritis and renal function, its role in the antiviral innate immune response in tubular epithelial cells remains unknown. In this study, we investigated the association between CYLD and TLR3-mediated CCL5 production in cultured human renal proximal tubular epithelial cells (hRPTECs). METHODS AND RESULTS: Polyinosinic-polycytidylic acid (poly IC), a synthetic TLR3 ligand, was used to stimulate hRPTECs. mRNA expression was measured using reverse transcription-quantitative polymerase chain reaction. Protein expression was assayed using western blotting or an enzyme-linked immunosorbent assay. Knockdown of IFN-ß, nuclear factor-kappa B (NF-κB) p65, and CYLD was performed by transfecting cells with specific small interfering RNAs. The intracellular localization of CYLD in hRPTECs was analyzed using immunofluorescence. Poly IC induced CCL5 expression in a time- and concentration-dependent manner, and knockdown of either IFN-ß or p65 reduced poly IC-induced CCL5 expression. CYLD knockdown increased the poly IC-induced CCL5, phosphorylated IκB kinase α/ß (IKK complex), and phosphorylated p65 expression. The CYLD protein was localized in the cytoplasm, and poly IC did not alter its expression. CONCLUSION: CYLD may prevent excessive inflammation due to an antiviral innate immune response by suppressing IKK complex and NF-κB activation downstream of TLR3 in hRPTECs.

Unraveling the unphosphorylated STAT3-unphosphorylated NF-κB pathway in loss of function STAT3 Hyper IgE syndrome.

Background: Patients with loss of function signal transducer and activator of transcription 3-related Hyper IgE Syndrome (LOF STAT3 HIES) present with recurrent staphylococcal skin and pulmonary infections along with the elevated serum IgE levels, eczematous rashes, and skeletal and facial abnormalities. Defective STAT3 signaling results in reduced Th17 cells and an impaired IL-17/IL-22 response primarily due to a compromised canonical Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway that involves STAT3 phosphorylation, dimerization, nuclear translocation, and gene transcription. The non-canonical pathway involving unphosphorylated STAT3 and its role in disease pathogenesis, however, is unexplored in HIES. Objective: This study aims to elucidate the role of unphosphorylated STAT3-unphosphorylated NF-κB (uSTAT3-uNF-κB) activation pathway in LOF STAT3 HIES patients. Methodology: The mRNA expression of downstream molecules of unphosphorylated STAT3-unphosphorylated NF-κB pathway was studied in five LOF STAT3 HIES patients and transfected STAT3 mutants post-IL-6 stimulation. Immunoprecipitation assays were performed to assess the binding of STAT3 and NF-κB to RANTES promoter. Results: A reduced expression of the downstream signaling molecules of the uSTAT3-uNF-κB complex pathway, viz., RANTES, STAT3, IL-6, IL-8, ICAM1, IL-8, ZFP36L2, CSF1, MRAS, and SOCS3, in LOF STAT3 HIES patients as well as the different STAT3 mutant plasmids was observed. Immunoprecipitation studies showed a reduced interaction of STAT3 and NF-κB to RANTES in HIES patients. Conclusion: The reduced expression of downstream signaling molecules, specially RANTES and STAT3, confirmed the impaired uSTAT3-uNF-κB pathway in STAT3 LOF HIES. Decreased levels of RANTES and STAT3 could be a significant component in the disease pathogenesis of Hyper IgE Syndrome.

High-dose radiation-induced immunogenic cell death of bladder cancer cells leads to dendritic cell activation.

Radiotherapy is a commonly used method in the treatment of bladder cancers (BC). Radiation-induced immunogenic cell death (ICD) is related to the immune response against cancers and their prognoses. Even though dendritic cells (DC) act as powerful antigen-presenting cells in the body, their precise role in this ICD process remains unclear. Accordingly, an in vitro study was undertaken to ascertain whether high-dose radiation-induced ICD of BC cells could regulate the immune response of DC. The results indicated that high-dose radiation treatments of BC cells significantly increased their levels of apoptosis, blocked their cell cycle in the G2/M phase, increased their expression of ICD-related proteins, and upregulated their secretion of CCL5 and CCL21 which control the directed migration of DC. It was also noted that expression of CD80, CD86, CCR5, and CCR7 on DC was upregulated in the medium containing the irradiated cells. In conclusion, the present findings illustrate that high-dose radiation can induce the occurrence of ICD within BC cells, concomitantly resulting in the activation of DC. Such findings could be of great significance in increasing the understanding how radiotherapy of BC may work to bring about reductions in cell activity and how these processes in turn lead to immunoregulation of the function of DC.

Cytokine dysregulation in amnestic mild cognitive impairment.

The pathophysiology of amnestic Mild Cognitive Impairment (aMCI) is largely unknown, although some papers found signs of immune activation. To assess the cytokine network in aMCI after excluding patients with major depression (MDD) and to examine the immune profiles of quantitative aMCI (qMCI) and distress symptoms of old age (DSOA) scores. A case-control study was conducted on 61 Thai aMCI participants and 60 healthy old adults (both without MDD). The Bio-Plex Pro human cytokine 27-plex test kit was used to assay cytokines/chemokines/growth factors in fasting plasma samples. aMCI is characterized by a significant immunosuppression, and reductions in T helper 1 (Th)1 and T cell growth profiles, the immune-inflammatory responses system, interleukin (IL)1ß, IL6, IL7, IL12p70, IL13, GM-CSF, and MCP-1. These 7 cytokines/chemokines exhibit neuroprotective effects at physiologic concentrations. In multivariate analyses, three neurotoxic chemokines, CCL11, CCL5, and CXCL8, emerged as significant predictors of aMCI. Logistic regression showed that aMCI was best predicted by combining IL7, IL1ß, MCP-1, years of education (all inversely associated) and CCL5 (positively associated). We found that 38.2% of the variance in the qMCI score was explained by IL7, IL1ß, MCP-1, IL13, years of education (inversely associated) and CCL5 (positively associated). The DSOA was not associated with any immune data. An imbalance between lowered levels of neuroprotective cytokines and chemokines, and relative increases in neurotoxic chemokines are key factors in aMCI. Future MCI research should always control for the confounding effects of affective symptoms.

Comprehensive analysis of the potential biological significance of CCL5 in pan-cancer prognosis and immunotherapy.

C-C chemokine ligand 5 (CCL5) plays a crucial role in the advancement of human cancer. Nevertheless, little is known about the multi-omics characterisation of CCL5 and its significance for the immune microenvironment and prognosis of tumor patients. The basal expression levels of the CCL5 gene in normal human tissues, aberrant expression in disease, genomic alterations, prognostic roles, pathway enrichment, immune microenvironment, association with immune checkpoints, drug sensitivity, and the ability to predict patients' immunotherapeutic response to immune checkpoint inhibitors (ICIs) and small molecule drugs were all thoroughly analyzed using data gathered from 33 cancers. Lastly, we were able to validate CCL5's involvement in renal clear cell carcinoma by experimental means. We discovered that CCL5 has distinct expression patterns and a diagnostic biomarker significance in cancer. Furthermore, we discovered that CCL5 is essential for both the tumor microenvironment and pan-cancer. TMB and MSI are two frequent immunological checkpoints that are significantly correlated with CCL5, and patients who express high levels of CCL5 have stronger immunotherapeutic response and a better prognosis after immunotherapy. Eventually, molecular docking was used to find small molecule inhibitors that can specifically target CCL5. Ultimately, it was shown that CCL5 knockdown impeded renal clear cell carcinoma cells' ability to proliferate and invade. Our findings demonstrate the significant potential of CCL5 as an immunotherapeutic response biomarker and prognostic indicator, which may pave the way for more studies on the mechanism of tumor infiltration and CCL5's potential therapeutic applications in cancer.

High mobility group box-1 protein promotes astrocytic CCL5 production through the MAPK/NF-κB pathway following spinal cord injury.

Astrocytes act as immune cells that can produce a series of chemokines to attract large numbers of leucocytes to the lesion site, where they contribute to excessive inflammation following spinal cord injury (SCI). However, the relevant regulatory mechanism involved in chemokine production by astrocytes has not been fully elucidated. In the present study, we examined the correlation between C-C motif chemokine ligand 5 (CCL5) and high mobility group box-1 protein (HMGB1) in a T8-T10 spinal cord contusion model. Our results revealed that SCI-induced CCL5 protein levels increased synchronously with the increase in HMGB1. Administration of an HMGB1-neutralizing antibody significantly reduced the protein expression of CCL5 in the context of SCI. An in vitro study revealed that HMGB1 binding with TLR2/4 receptors potently facilitates the production of CCL5 by astrocytes by activating the intracellular ERK/JNK-mediated NF-κB pathway. Furthermore, the HMGB1-induced release of CCL5 from astrocytes is involved in promoting microglia/macrophage accumulation and M1 polarization. The inhibition of HMGB1 activity reduces microglia/macrophage infiltration by decreasing the expression of CCL5 and improves motor functional recovery following SCI. Our results provide insights into the new functions of HMGB1-mediated astrocytic CCL5 production, which elicits inflammatory cell recruitment to the site of injury; this recruitment is associated with excessive inflammation activation. These data may provide a new therapeutic strategy for central nervous system (CNS) inflammation.

Kinetics and Prognosis Value of CCL5/RANTES at the Acute Phase of ST-Segment-Elevation Myocardial Infarction.

BACKGROUND: RANTES (regulated upon activation, normal T cell expressed, and secreted) or CCL5 (CC chemokine ligand 5) is a chemokine that mediates chemotaxis and activation of T cells, monocytes, mast cells, and dendritic cells. It is involved in the pathogenesis of several diseases, including atherosclerosis, but its role at the acute phase of myocardial infarction (MI) is unclear. Our objective is to determine whether the serum level of RANTES is a marker of the severity of acute MI. METHODS AND RESULTS: The study included 250 consecutive patients with ST-segment-elevation MI who underwent percutaneous coronary intervention in a prospective cohort. Peripheral venous blood samples were taken at 5 time points and ELISA was performed. Major adverse cardiovascular events were prospectively recorded over the 12-month follow-up. Serum RANTES level raised from 12.9 (8.0-20.7) ng/mL at H0 to 13.9 (7.4-22.4) ng/mL at H4 and decreased gradually until 1 month at 9.7 (5.4-13.6) ng/mL (P<0.0001). RANTES area under the curve (AUC) level was not correlated with infarct size (r=-0.03, P=0.70) or left ventricular ejection fraction assessed by magnetic resonance imaging (r=0.02, P=0.80). Patients with a RANTES AUC serum level below the first tertile value of the population (411.0 ng.h.mL-1) were more likely to have a major adverse cardiovascular event during the first 12 months after ST-segment-elevation MI (hazard ratio [HR], 2.9 [1.3-6.6], P=0.01). In a multivariable Cox regression analysis, serum level below the first tertile remained associated with an increased risk of experiencing major adverse cardiovascular event during the follow-up (adjusted HR, 2.6 [1.2-5.8], P=0.02). CONCLUSIONS: A low level of circulating RANTES post ST-segment-elevation MI was associated with an increased risk of experiencing major adverse cardiovascular event and might be a valuable prognostic marker in patients with ST-segment-elevation MI.

The RIG-I-like receptor signaling pathway triggered by Staphylococcus aureus promotes breast cancer metastasis.

Host microbes are increasingly recognized as key components in various types of cancer, although their exact impact remains unclear. This study investigated the functional significance of Staphylococcus aureus (S. aureus) in breast cancer tumorigenesis and progression. We found that S. aureus invasion resulted in a compromised DNA damage response process, as evidenced by the absence of G1-phase arrest and apoptosis in breast cells in the background of double strand breaks production and the activation of the ataxia-telangiectasia mutated (ATM)-p53 signaling pathway. The high-throughput mRNA sequencing, bioinformatics analysis and pharmacological studies revealed that S. aureus facilitates breast cell metastasis through the innate immune pathway, particularly in cancer cells. During metastasis, S. aureus initially induced the expression of RIG-I-like receptors (RIG-I in normal breast cells, RIG-I and MDA5 in breast cancer cells), which in turn activated NF-κB p65 expression. We further showed that NF-κB p65 activated the CCL5-CCR5 pathway, contributing to breast cell metastasis. Our study provides novel evidence that the innate immune system, triggered by bacterial infection, plays a role in bacterial-driven cancer metastasis.

CCL5 promotes the epithelial-mesenchymal transition of circulating tumor cells in renal cancer.

BACKGROUND: Circulating tumor cells (CTCs) are pivotal in tumor metastasis across cancers, yet their specific role in renal cancer remains unclear. METHODS: This study investigated C-C motif chemokine ligand 5 (CCL5)'s tumorigenic impact on renal cancer cells and CTCs using bioinformatics, in vivo, and in vitro experiments. It also assessed renal cancer patients' CTCs prognostic value through Lasso regression and Kaplan-Meier survival curves. RESULTS: Bioinformatics analysis revealed differential genes focusing on cellular adhesion and migration between CTCs and tumor cells. CCL5 exhibited high expression in various CTCs, correlating with poor prognosis in renal cancer. In 786-O-CTCs, CCL5 enhanced malignancy, while in renal cell carcinoma cell line CAKI-2 and 786-O, it promoted epithelial-mesenchymal transition (EMT) via smad2/3, influencing cellular characteristics. The nude mouse model suggested CCL5 increased CTCs and intensified EMT, enhancing lung metastasis. Clinical results shown varying prognostic values for different EMT-typed CTCs, with mesenchymal CTCs having the highest value. CONCLUSIONS: In summary, CCL5 promoted EMT in renal cancer cells and CTCs through smad2/3, enhancing the malignant phenotype and facilitating lung metastasis. Mesenchymal-type CTC-related factors can construct a risk model for renal cancer patients, allowing personalized treatment based on metastatic risk prediction.

Establishment and verification of a TME prognosis scoring model based on the acute myeloid leukemia single-cell transcriptome.

The tumor microenvironment (TME) plays an important role in the occurrence and progression of Acute Myeloid Leukemia (AML). Single-cell sequencing has enabled researchers to explore the correlation between TME subgroups and tumor prognosis, distinguish the existence of drug-resistant subgroups of tumor cells, and unravel the complexity of the AML cellular heterogeneity. We used bone marrow immune cell enrichment analysis from public databases to screen prognostic genes, construct prognostic models, and validate their prognostic significance on independent external datasets and patient samples. A total of 18,251 single cells were obtained to establish prognostic scoring models for 10 key genes including CCL5, ETLS2, and IL2RA.The AML cases were divided into two groups: high-risk and low-risk. The low-risk group exhibited a higher survival rate than the high-risk group. The areas under curves (AUC) of 1-, 3- and 5-year survival curves in the TCGA and GEO training sets were greater than 0.8 and 0.6, respectively, indicating effective prediction. The model's prognostic efficacy was confirmed across multiple validation sets. It demonstrated increased expression of ETS2, CCL5, and IL2RA in AML samples compared to controls, which was associated with decreased overall survival (OS). This prognostic scoring model based on tumor immune infiltration provides a reference for developing novel treatment strategies for recurrent/refractory AML.

cGAS-activated endothelial cell-T cell cross-talk initiates tertiary lymphoid structure formation.

Aberrant activation of the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) pathway causes autoimmunity in humans and mice; however, the exact mechanism by which the cGAS-STING pathway initiates adaptive immunity and tissue pathology is still not fully understood. Here, we used a cGAS knockin (KI) mouse model that develops systemic autoimmunity. In the lungs of cGAS-KI mice, blood vessels were enclosed by organized lymphoid tissues that resemble tertiary lymphoid structures (TLSs). Cell-intrinsic cGAS induction promoted up-regulation of CCR5 in CD8+ T cells and led to CCL5 production in vascular endothelial cells. Peripheral CD8+ T cells were recruited to the lungs and produced CXCL13 and interferon-γ. The latter triggered endothelial cell death, potentiated CCL5 production, and was essential for TLS establishment. Blocking CCL5 or CCR5, or depleting CD8+ T cells, impaired TLS formation. cGAS-mediated TLS formation also enhanced humoral and antitumor responses. These data demonstrate that cGAS signaling drives a specialized lymphoid structure that underlies autoimmune tissue pathology.

FBXL19 in endothelial cells protects the heart from influenza A infection by enhancing antiviral immunity and reducing cellular senescence programs.

Influenza A virus (IAV) infection while primarily affecting the lungs, is often associated with cardiovascular complications. However, the mechanisms underlying this association are not fully understood. Here, we investigated the potential role of FBXL19, a member of the Skp1-Cullin-1-F-box family of E3 ubiquitin ligase, in IAV-induced cardiac inflammation. We demonstrated that FBXL19 overexpression in endothelial cells (ECs) reduced viral titers and IAV matrix protein 1 (M1) levels while increasing antiviral gene expression, including interferon (IFN)-α, -ß, and -γ and RANTES (regulated on activation normal T cell expressed and secreted) in the cardiac tissue of IAV-infected mice. Moreover, EC-specific overexpression of FBXL19 attenuated the IAV infection-reduced interferon regulatory factor 3 (IRF3) level without altering its mRNA level and suppressed cardiac inflammation. Furthermore, IAV infection triggered cellular senescence programs in the heart as indicated by the upregulation of p16 and p21 mRNA levels and the downregulation of lamin-B1 levels, which were partially reversed by FBXL19 overexpression in ECs. Our findings indicate that EC-specific overexpression of FBXL19 protects against IAV-induced cardiac damage by enhancing interferon-mediated antiviral signaling, reducing cardiac inflammation, and suppressing cellular senescence programs.NEW & NOTEWORTHY Our study reveals a novel facet of IAV infection, demonstrating that it can trigger cellular senescence within the heart. Intriguingly, upregulation of endothelial FBXL19 promotes host innate immunity, reduces cardiac senescence, and diminishes inflammation. These findings highlight the therapeutic potential of targeting FBXL19 to mitigate IAV-induced cardiovascular complications.

Adipose-derived mesenchymal stem cells suppress fibroblast proliferation of hypertrophic scar through CCL5 and CXCL12.

BACKGROUND AND OBJECTIVE: Adipose-derived mesenchymal stem cells (ADSCs) can accelerate wound healing, reduce scar formation, and inhibit hypertrophic scar (HTS). ADSCs can secrete a large amount of CCL5, and CCL5 has been proved to be pro-inflammatory and pro-fibrotic. CXCL12 (SDF-1) is a key chemokine that promotes stem cell migration and survival. Therefore, this study selected normal skin and HTS conditioned medium to simulate different microenvironments, and analyzed the effects of different microenvironments on the expression of CCL5 and CXCL12 in human ADSCs (hADSCs). MATERIALS AND METHODS: hADSCs with silenced expression of CCL5 and CXCL12 were co-cultured with hypertrophic scar fibroblasts to verify the effects of CCL5 and CXCL12 in hADSCs on the proliferation ability of hypertrophic scar fibroblasts. A mouse model of hypertrophic scar was established to further confirm the effect of CCL5 and CXCL12 in hADSCs on hypertrophic scar formation. RESULTS: CCL5 level was found to be significantly high in hADSCs cultured in HTS conditioned medium. CXCL12 in HTS group was prominently lowly expressed compared with the normal group. Inhibition of CCL5 in hADSCs enhanced the effects of untreated hADSCs on proliferation of HTS fibroblasts while CXCL12 knockdown exerted the opposite function. Inhibition of CCL5 in hADSCs increased the percentage of HTS fibroblasts in the G0/G1 phase while down-regulation of CXCL12 decreased those. Meanwhile, the down-regulated levels of fibroblast markers including collagen I, collagen III, and α-SMA induced by CCL5 knockdown were significantly up-regulated by CXCL12 inhibition. hADSCs alleviate the HTS of mice through CCL5 and CXCL12. CONCLUSION: In summary, our results demonstrated that hADSCs efficiently cured HTS by suppressing proliferation of HTS fibroblasts, which may be related to the inhibition of CXCL12 and elevation of CCL5 in hADSCs, suggesting that hADSCs may provide an alternative therapeutic approach for the treatment of HTS.

Robust CXCL10/IP-10 and CCL5/RANTES Production Induced by Tick-Borne Encephalitis Virus in Human Brain Pericytes Despite Weak Infection.

Tick-borne encephalitis virus (TBEV) targets the central nervous system (CNS), leading to potentially severe neurological complications. The neurovascular unit plays a fundamental role in the CNS and in the neuroinvasion of TBEV. However, the role of human brain pericytes, a key component of the neurovascular unit, during TBEV infection has not yet been elucidated. In this study, TBEV infection of the primary human brain perivascular pericytes was investigated with highly virulent Hypr strain and mildly virulent Neudoerfl strain. We used Luminex assay to measure cytokines/chemokines and growth factors. Both viral strains showed comparable replication kinetics, peaking at 3 days post infection (dpi). Intracellular viral RNA copies peaked at 6 dpi for Hypr and 3 dpi for Neudoerfl cultures. According to immunofluorescence staining, only small proportion of pericytes were infected (3% for Hypr and 2% for Neudoerfl), and no cytopathic effect was observed in the infected cells. In cell culture supernatants, IL-6 production was detected at 3 dpi, together with slight increases in IL-15 and IL-4, but IP-10, RANTES and MCP-1 were the main chemokines released after TBEV infection. These chemokines play key roles in both immune defense and immunopathology during TBE. This study suggests that pericytes are an important source of these signaling molecules during TBEV infection in the brain.

Ritlecitinib, a JAK3/TEC family kinase inhibitor, stabilizes active lesions and repigments stable lesions in vitiligo.

The efficacy of ritlecitinib, an oral JAK3/TEC family kinase inhibitor, on active and stable lesions was evaluated in patients with active non-segmental vitiligo in a phase 2b trial (NCT03715829). Patients were randomized to placebo or daily ritlecitinib 50 mg (with or without 4-week 100-mg or 200-mg loading dose), 30 mg, or 10 mg for 24 weeks. Active lesions showed greater baseline expression of inflammatory/immune markers IFNG and CCL5, levels of CD103, and T-cell infiltrates than stable lesions. Patients with more active than stable vitiligo lesions showed higher baseline serum levels of CXCL9 and PD-L1, while patients with more stable than active lesions showed higher baseline serum levels of HO-1. At Week 24, ritlecitinib 50 mg significantly stabilized mean percent change from baseline in depigmentation extent in both active lesions and stable lesions vs. placebo-response, with stable lesions showing greater repigmentation. After 24 weeks of treatment, ritlecitinib 50 mg increased expression of melanocyte markers in stable lesions, while Th1/Th2-related and co-stimulatory molecules decreased significantly in both stable and active lesions. Serum from patients with more active than stable lesions showed decreased levels of ICOS and NK cell activation markers. These data, confirmed at transcription/protein levels, indicate that stable lesion repigmentation occurs early with ritlecitinib, while active lesions require stabilization of inflammation first. ClinicalTrials.gov: NCT03715829.

Bacterial peptidoglycan signalling in microglia: Activation by MDP via the NF-κB/MAPK pathway.

Bacterial peptidoglycan (PGN) fragments are commonly studied in the context of bacterial infections. However, PGN fragments recently gained recognition as signalling molecules from the commensal gut microbiota in the healthy host. Here we focus on the minimal bioactive PGN motif muramyl dipeptide (MDP), found in both Gram-positive and Gram-negative commensal bacteria, which signals through the Nod2 receptor. MDP from the gut microbiota translocates to the brain and is associated with changes in neurodevelopment and behaviour, yet there is limited knowledge about the underlying mechanisms. In this study we demonstrate that physiologically relevant doses of MDP induce rapid changes in microglial gene expression and lead to cytokine and chemokine secretion. In immortalised microglial (IMG) cells, C-C Motif Chemokine Ligand 5 (CCL5/RANTES) expression is acutely sensitive to the lowest physiologically prevalent dose (0.1 µg/ml) of MDP. As CCL5 plays an important role in memory formation and synaptic plasticity, microglial CCL5 might be the missing link in elucidating MDP-induced alterations in synaptic gene expression. We observed that a higher physiological dose of MDP elevates the expression of cytokines TNF-α and IL-1ß, indicating a transition toward a pro-inflammatory phenotype in IMG cells, which was validated in primary microglial cultures. Furthermore, MDP induces the translocation of NF-κB subunit p65 into the nucleus, which is blocked by MAPK p38 inhibitor SB202190, suggesting that an interplay of both the NF-κB and MAPK pathways is responsible for the MDP-specific microglial phenotype. These findings underscore the significance of different MDP levels in shaping microglial function in the CNS and indicate MDP as a potential mediator for early inflammatory processes in the brain. It also positions microglia as an important target in the gut microbiota-brain-axis pathway through PGN signalling.