The novel potential therapeutic target PSMP/MSMP promotes acute kidney injury via CCR2.

Acute kidney injury (AKI) is a major worldwide health concern that currently lacks effective medical treatments. PSMP is a damage-induced chemotactic cytokine that acts as a ligand of CCR2 and has an unknown role in AKI. We have observed a significant increase in PSMP levels in the renal tissue, urine, and plasma of patients with AKI. PSMP deficiency improved kidney function and decreased tubular damage and inflammation in AKI mouse models induced by kidney ischemia-reperfusion injury, glycerol, and cisplatin. Single-cell RNA sequencing analysis revealed that Ly6Chi or F4/80lo infiltrated macrophages (IMs) were a major group of proinflammatory macrophages with strong CCR2 expression in AKI. We observed that PSMP deficiency decreased CCR2+Ly6Chi or F4/80lo IMs and inhibited M1 polarization in the AKI mouse model. Moreover, overexpressed human PSMP in the mouse kidney could reverse the attenuation of kidney injury in a CCR2-dependent manner, and this effect could be achieved without CCL2 involvement. Extracellular PSMP played a crucial role, and treatment with a PSMP-neutralizing antibody significantly reduced kidney injury in vivo. Therefore, PSMP might be a therapeutic target for AKI, and its antibody is a promising therapeutic drug for the treatment of AKI.

CCR2 is a potential therapeutic target in peri-implantitis.

AIM: CCR2 (C-C chemokine receptor type 2) plays a crucial role in inflammatory and bone metabolic diseases; however, its role in peri-implantitis remains unclear. This study aimed to explore whether CCR2 contributes to peri-implantitis and the treatment effects of cenicriviroc (CVC) on peri-implant inflammation and bone resorption. MATERIALS AND METHODS: The expression of CCR2 was studied using clinical tissue analysis and an in vivo peri-implantitis model. The role of CCR2 in promoting inflammation and bone resorption in peri-implantitis was evaluated in Ccr2-/- mice and wild-type mice. The effect of CVC on peri-implantitis was evaluated using systemic and local dosage forms. RESULTS: Human peri-implantitis tissues showed increased CCR2 and CCL2 levels, which were positively correlated with bone loss around the implants. Knocking out Ccr2 in an experimental model of peri-implantitis resulted in decreased monocyte and macrophage infiltration, reduced pro-inflammatory cytokine generation and impaired osteoclast activity, leading to reduced inflammation and bone loss around the implants. Treatment with CVC ameliorated bone loss in experimental peri-implantitis. CONCLUSIONS: CCR2 may be a potential target for peri-implantitis treatment by harnessing the immune-inflammatory response to modulate the local inflammation and osteoclast activity.

CCL2 is a key regulator and therapeutic target for periodontitis.

AIM: Our previous study revealed that the C-C motif chemokine receptor 2 (CCR2) is a promising target for periodontitis prevention and treatment. However, CCR2 is a receptor with multiple C-C motif chemokine ligands (CCLs), including CCL2, CCL7, CCL8, CCL13 and CCL16, and which of these ligands plays a key role in periodontitis remains unclear. The aim of the present study was to explore the key functional ligand of CCR2 in periodontitis and to evaluate the potential of the functional ligand as a therapeutic target for periodontitis. MATERIALS AND METHODS: The expression levels and clinical relevance of CCR2, CCL2, CCL7, CCL8, CCL13 and CCL16 were studied using human samples. The role of CCL2 in periodontitis was evaluated by using CCL2 knockout mice and overexpressing CCL2 in the periodontium. The effect of local administration of bindarit in periodontitis was evaluated by preventive and therapeutic medication in a mouse periodontitis model. Microcomputed tomography, haematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, bead-based immunoassays and flow cytometry were used for histomorphology, molecular biology and cytology analysis. RESULTS: Among different ligands of CCR2, only CCL2 was significantly up-regulated in periodontitis gingival tissues and was positively correlated with the severity of periodontitis. Mice lacking CCL2 showed milder inflammation and less bone resorption than wild-type mice, which was accompanied by a reduction in monocyte/macrophage recruitment. Adeno-associated virus-2 vectors overexpressing CCL2 in Ccl2-/- mice gingiva reversed the attenuation of periodontitis in a CCR2-dependent manner. In ligation-induced experimental periodontitis, preventive or therapeutic administration of bindarit, a CCL2 synthesis inhibitor, significantly inhibited the production of CCL2, decreased the osteoclast number and bone loss and reduced the expression levels of proinflammatory cytokines TNF-α, IL-6 and IL-1ß. CONCLUSIONS: CCL2 is a pivotal chemokine that binds to CCR2 during the progression of periodontitis, and targeting CCL2 may be a feasible option for controlling periodontitis.

FAM19A5/TAFA5, a novel neurokine, plays a crucial role in depressive-like and spatial memory-related behaviors in mice.

FAM19A5/TAFA5 is a member of the family with sequence similarity 19 with unknown function in emotional and cognitive regulation. Here, we reported that FAM19A5 was highly expressed in the embryonic and postnatal mouse brain, especially in the hippocampus. Behaviorally, genetic deletion of Fam19a5 resulted in increased depressive-like behaviors and impaired hippocampus-dependent spatial memory. These behavioral alterations were associated with the decreased expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and N-methyl-D-aspartic acid receptors, as well as significantly reduced glutamate release and neuronal activity in the hippocampus. Subsequently, these changes led to the decreased density of dendritic spines. In recent years, the roles of chronic stress participating in the development of depression have become increasingly clear, but the mechanism remains to be elucidated. We found that the levels of FAM19A5 in plasma and hippocampus of chronic stress-treated mice were significantly decreased whereas overexpression of human FAM19A5 selectively in the hippocampus could attenuate chronic stress-induced depressive-like behaviors. Taken together, our results revealed for the first time that FAM19A5 plays a key role in the regulation of depression and spatial cognition in the hippocampus. Furthermore, our study provided a new mechanism for chronic stress-induced depression, and also provided a potential biomarker for the diagnosis and a new strategy for the treatment of depression.

Critical roles for CCR2 and the therapeutic potential of cenicriviroc in periodontitis: A pre-clinical study.

AIM: CCR2 plays important roles in many inflammatory and bone metabolic diseases, but its specific role in periodontitis is unknown. In the present study, we aimed to explore the role of CCR2 in the progression of periodontitis and evaluate the effect of cenicriviroc (CVC) on periodontitis. MATERIALS AND METHODS: The expression of CCR2 was studied in patients with periodontitis and in ligation-induced murine model of periodontitis. The role of CCR2 in promoting inflammation and bone resorption in periodontitis was evaluated in Ccr2-/- mice and wild-type mice. The effect of CVC in the prevention and treatment of periodontitis was evaluated by systemic and local medication. Microcomputed tomography, haematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and flow cytometry were used for histomorphology, molecular biology, and cytology analysis, respectively. RESULTS: In this study, we demonstrated that CCR2 was highly expressed in human and murine periodontitis and that CCR2 deficiency was associated with decreased inflammatory monocyte and macrophage infiltration and inflammatory mediators, osteoclast number and alveolar bone resorption. Prevention and treatment with CVC significantly reduced the severity of periodontitis, regardless of whether it was administered systemically or locally. CONCLUSIONS: CCR2 plays an important role in the development and progression of periodontitis, and CVC is a potential drug for the prevention and treatment of periodontitis.

PSMP/MSMP promotes hepatic fibrosis through CCR2 and represents a novel therapeutic target.

BACKGROUND & AIMS: C-C motif chemokine receptor 2 (CCR2) has been recognized as a promising target for the treatment of liver fibrosis. PC3-secreted microprotein (PSMP)/microseminoprotein (MSMP) is a novel chemotactic cytokine and its receptor is CCR2. In the present study we investigated the expression and role of PSMP in liver fibrosis/cirrhosis. METHODS: PSMP expression was studied in patients with fibrosis/cirrhosis and in 3 murine models of liver fibrosis, including mice treated with carbon tetrachloride (CCl4), bile-duct ligation, or a 5-diethoxycarbonyl-1,4-dihydrocollidine diet. The role of PSMP was evaluated in Psmp-/- mice and after treatment with a PSMP antibody in wild-type mice. The direct effects of PSMP on macrophages and hepatic stellate cells were studied in vitro. RESULTS: In this study, we found that PSMP was highly expressed in fibrotic/cirrhotic tissues from patients with different etiologies of liver disease and in the 3 experimental mouse models of fibrosis. Damage-associated molecular pattern molecules HMGB-1 and IL-33 induced hepatocytes to produce PSMP. PSMP deficiency resulted in a marked amelioration of hepatic injury and fibrosis. In CCl4-induced hepatic injury, the infiltration of macrophages and CCR2+ monocytes into the liver was significantly decreased in Psmp-/- mice. Consistent with the decreased levels of intrahepatic macrophages, proinflammatory cytokines were significantly reduced. Moreover, adeno-associated virus-8 vectors successfully overexpressing human PSMP in Psmp-/- mouse livers could reverse the attenuation of liver injury and fibrosis induced by CCl4 in a CCR2-dependent manner. Treatment with a specific PSMP-neutralizing antibody, 3D5, prevented liver injury and fibrosis induced by CCl4 in mice. At the cellular level, PSMP directly promoted M1 polarization of macrophages and activation of LX-2 cells. CONCLUSION: PSMP enhances liver fibrosis through its receptor, CCR2. PSMP is a potentially attractive therapeutic target for the treatment of patients with liver fibrosis. LAY SUMMARY: Our present study identifies the essential role of the protein PSMP for the development and progression of liver fibrosis in humans and mice. PSMP promotes liver fibrosis through inflammatory macrophage infiltration, polarization and production of proinflammatory cytokines, as well as direct activation of hepatic stellate cells via its receptor CCR2. A PSMP antibody can significantly reduce liver fibrosis development in vivo. These findings indicate that PSMP is a potential therapeutic target and its antibody is a potential therapeutic agent for the treatment of liver fibrosis.

Comparative Transcriptome Analysis of Gingival Immune-Mediated Inflammation in Peri-Implantitis and Periodontitis Within the Same Host Environment.

Objective: This investigation aimed to determine whether and to what extent there are transcriptional differences between periodontitis and peri-implantitis in the same susceptible host. Background: As an immune-mediated inflammatory disease resulting in aggressive bone resorption around dental implants, peri-implantitis constitutes a major threat to dental implants' long-term success. Compared to periodontitis, its etiological molecular mechanism remains elusive. Currently, there are few investigations on these two diseases at the transcriptional level within the same basal environment. Methods: Ligature-induced peri-implantitis and periodontitis were generated in the same mice. Gingival tissues of healthy, periodontitis, and peri-implantitis sites from the same oral cavity were collected and used for RNA sequencing. Differentially expressed genes (DEGs) were screened between periodontitis/peri-implantitis and healthy sites. Enrichment analysis of DEGs was performed. The comprehensive immune landscape was annotated by seq-ImmuCC. Hub genes from peri-implantitis-specific DEGs were filtered using the STRING database and Cytoscape. Validation of the selected hub genes was performed on the GEO106090 dataset (gingival tissues from six periodontitis patients, six peri-implantitis patients, and six healthy controls). Results: The results indicated that peri-implantitis and periodontitis exhibited significantly distinct transcriptional signatures, with the complement and coagulation cascade pathways and osteoclast differentiation predominating in peri-implantitis mucosa. Compared with periodontitis, peri-implantitis sites exhibited elevated macrophage proportions and relatively enriched macrophage activation and bone loss. Hub genes were selected, and IL1B, CCL3, and CLEC4E were significantly highly expressed in human peri-implantitis mucosa. Conclusion: The study suggests that the interplay between macrophages and bone resorption seems to be more robust than in periodontitis. IL1B, CCL3, and CLEC4E may be considered promising therapeutic targets for peri-implantitis. These critical biological processes and identified genes may contribute to the etiology of peri-implantitis, which is unique from periodontitis. This work may make way for deeper exploration and contribute significantly to the treatment and prevention of peri-implantitis.