Functional Roles of Chemokine Receptor CCR2 and Its Ligands in Liver Disease

Chemokines are a family of cytokines that orchestrate the migration and positioning of immune cells within tissues and are critical for the function of the immune system. CCR2 participates in liver pathology, including acute liver injury, chronic hepatitis, fibrosis/cirrhosis, and tumor progression, by mediating the recruitment of immune cells to inflammation and tumor sites. Although a variety of chemokines have been well studied in various diseases, there is no comprehensive review presenting the roles of all known chemokine ligands of CCR2 (CCL2, CCL7, CCL8, CCL12, CCL13, CCL16, and PSMP) in liver disease, and this review aims to fill this gap. The introduction of each chemokine includes its discovery, its corresponding chemotactic receptors, physiological functions and roles in inflammation and tumors, and its impact on different immune cell subgroups.

FAM3D is essential for colon homeostasis and host defense against inflammation associated carcinogenesis

The physiological homeostasis of gut mucosal barrier is maintained by both genetic and environmental factors and its impairment leads to pathogenesis such as inflammatory bowel disease. A cytokine like molecule, FAM3D (mouse Fam3D), is highly expressed in mouse gastrointestinal tract. Here, we demonstrate that deficiency in Fam3D is associated with impaired integrity of colonic mucosa, increased epithelial hyper-proliferation, reduced anti-microbial peptide production and increased sensitivity to chemically induced colitis associated with high incidence of cancer. Pretreatment of Fam3D^−/− mice with antibiotics significantly reduces the severity of chemically induced colitis and wild type (WT) mice co-housed with Fam3D^−/− mice phenocopy Fam3D-deficiency showing increased sensitivity to colitis and skewed composition of fecal microbiota. An initial equilibrium of microbiota in cohoused WT and Fam3D^−/− mice is followed by an increasing divergence of the bacterial composition after separation. These results demonstrate the essential role of Fam3D in colon homeostasis, protection against inflammation associated cancer and normal microbiota composition.

The cytokine like protein FAM3D (Fam3D in mice) is highly expressed in the digestive tract with unknown role in colon pathophysiology. Here, by using gene deficient mice, the authors show that Fam3D is critically involved in colon homeostasis, host defense against colitis-associated carcinogenesis, and the balance of microbiota.

Identification of FAM3D as a novel endogenous chemotaxis agonist for the FPRs (formyl peptide receptors)

The family with sequence similarity 3 (FAM3) gene family is a cytokine-like gene family with four members FAM3A, FAM3B, FAM3C, and FAM3D. In this study, we found that FAM3D strongly chemoattracted human peripheral blood neutrophils and monocytes. To identify FAM3D receptor, we used chemotaxis, receptor internalization, calcium flux and radioligand-binding assays in FAM3D-stimulated HEK293 cells that transiently expressed FPR1 or FPR2 to show that FAM3D was a high affinity ligand of formyl peptide receptors (FPR1 and FPR2), both of which were highly expressed on the surface of neutrophils and monocytes/macrophages. After being injected into the mouse peritoneal cavity, FAM3D chemoattracted CD11b+Ly6G+ neutrophils in a short time. In response to FAM3D stimulation, p-ERK and p-p38 were up-regulated in the mouse neutrophils, which could be inhibited by an inhibitor of FPR1 or FPR2. FAM3D was reported to be constitutively expressed in the gastrointestinal tract. We found that FAM3D expression increased significantly in dextran sulfate sodium-induced colitis. Taken together, we propose that FAM3D plays a role in gastrointestinal homeostasis and inflammation through its receptors FPR1 and FPR2.

FAM19A1 is a new ligand for GPR1 that modulates neural stem-cell proliferation and differentiation

FAM19A1 is a member of the family with sequence similarity 19 with unknown function. FAM19A1 mRNA expression is restricted to the CNS. Here, we report that FAM19A1 is a classic secretory protein, and expression levels correlate with brain development, increasing from embryonic d 12.5, peaking between postnatal d (P)1 and P7 and decreasing at wk 8. The adult hippocampus is a region of FAM19A1 high expression. Recombinant FAM19A1 suppressed the proliferation and self-renewal of neural stem cells (NSCs) and altered the lineage progression of NSCs with promoted neuron differentiation and suppressed astrocyte differentiation. Although GPCR 1 (GPR1) has been reported to be expressed in the CNS, its functions in the brain remain unclear. We identified GPR1 to be a functional receptor for FAM19A1. FAM19A1 interacted with GPR1 via the N-terminal domain (GPR1-ND), and its NSC modulatory functions required the Rho-associated protein kinase (ROCK) /ERK1/2 and ROCK/signal transducer and activator of transcription 3 signaling pathways. GPR1-ND that selectively bound to FAM19A1 neutralized the effects of FAM19A1 on NSC functions. Taken together, our results show, for the first time to our knowledge, that FAM19A1 is a novel regulatory factor of the proliferation and differentiation of NSCs, and identified a novel mechanism by which GPCR mediates the effects of FAM19A1 on NSC functions that may be important for brain development and neurogenesis. Additional exploration of the functions of FAM19A1 and GPR1 in the CNS may broaden the range of therapeutic options available for major brain disorders.-Zheng, C., Chen, D., Zhang, Y., Bai, Y., Huang, S., Zheng, D., Liang, W., She, S., Peng, X., Wang, P., Mo, X., Song, Q., Lv, P., Huang, J., Ye, R. D., Wang, Y. FAM19A1 is a new ligand for GPR1 that modulates neural stem-cell proliferation and differentiation.

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.

Brain substrates of perceived spatial separation between speech sources under simulated reverberant listening conditions in schizophrenia

BACKGROUND

People with schizophrenia recognize speech poorly under multiple-people-talking (informational masking) conditions. In reverberant environments, direct-wave signals from a speech source are perceptually integrated with the source reflections (the precedence effect), forming perceived spatial separation (PSS) between different sources and consequently improving target-speech recognition against informational masking. However, the brain substrates underlying the schizophrenia-related vulnerability to informational masking and whether schizophrenia affects the unmasking effect of PSS are largely unknown.

METHOD

Using psychoacoustic testing and functional magnetic resonance imaging, respectively, the speech recognition under either the PSS or perceived spatial co-location (PSC) condition and the underlying brain substrates were examined in 20 patients with schizophrenia and 16 healthy controls.

RESULTS

Speech recognition was worse in patients than controls. Under the PSS (but not PSC) condition, speech recognition was correlated with activation of the superior parietal lobule (SPL), and target speech-induced activation of the SPL, precuneus, middle cingulate cortex and caudate significantly declined in patients. Moreover, the separation (PSS)-against-co-location (PSC) contrast revealed (1) activation of the SPL, precuneus and anterior cingulate cortex in controls, (2) suppression of the SPL and precuneus in patients, (3) activation of the pars triangularis of the inferior frontal gyrus and middle frontal gyrus in both controls and patients, (4) activation of the medial superior frontal gyrus in patients, and (5) impaired functional connectivity of the SPL in patients.

CONCLUSIONS

Introducing the PSS listening condition efficiently reveals both the brain substrates underlying schizophrenia-related speech-recognition deficits against informational masking and the schizophrenia-related neural compensatory strategy for impaired SPL functions.

4-[(1H-imidazol-4-yl) methyl] benzamidines and benzylamidines: novel antagonists of the histamine H3 receptor

A series of amidine substituted phenyl-, benzyl-, and phenethylimidazoles based on the known H3 agonist SK&F 91606 (4) has been synthesized and tested as ligands for the histamine H3 receptor. Insertion of a phenyl ring between the imidazole ring and the amidine moiety produces antagonists. The benzyl series was found to be the most potent and was further investigated. Compounds 9c and 18 (entries 5 and 12, Table 1) are potent ligands for the H3 receptor with K(i) values of 16 nM and 7.2 nM respectively. In vivo, both compounds were shown to be equipotent to thioperamide (2), the standard H3 antagonist.

Brain substrates underlying auditory speech priming in healthy listeners and listeners with schizophrenia

BACKGROUND

Under 'cocktail party' listening conditions, healthy listeners and listeners with schizophrenia can use temporally pre-presented auditory speech-priming (ASP) stimuli to improve target-speech recognition, even though listeners with schizophrenia are more vulnerable to informational speech masking.

METHOD

Using functional magnetic resonance imaging, this study searched for both brain substrates underlying the unmasking effect of ASP in 16 healthy controls and 22 patients with schizophrenia, and brain substrates underlying schizophrenia-related speech-recognition deficits under speech-masking conditions.

RESULTS

In both controls and patients, introducing the ASP condition (against the auditory non-speech-priming condition) not only activated the left superior temporal gyrus (STG) and left posterior middle temporal gyrus (pMTG), but also enhanced functional connectivity of the left STG/pMTG with the left caudate. It also enhanced functional connectivity of the left STG/pMTG with the left pars triangularis of the inferior frontal gyrus (TriIFG) in controls and that with the left Rolandic operculum in patients. The strength of functional connectivity between the left STG and left TriIFG was correlated with target-speech recognition under the speech-masking condition in both controls and patients, but reduced in patients.

CONCLUSIONS

The left STG/pMTG and their ASP-related functional connectivity with both the left caudate and some frontal regions (the left TriIFG in healthy listeners and the left Rolandic operculum in listeners with schizophrenia) are involved in the unmasking effect of ASP, possibly through facilitating the following processes: masker-signal inhibition, target-speech encoding, and speech production. The schizophrenia-related reduction of functional connectivity between the left STG and left TriIFG augments the vulnerability of speech recognition to speech masking.

Dominant neoantigen verification in hepatocellular carcinoma by a single-plasmid system coexpressing patient HLA and antigen

BACKGROUND

Previous studies confirmed that most neoantigens predicted by algorithms do not work in clinical practice, and experimental validations remain indispensable for confirming immunogenic neoantigens. In this study, we identified the potential neoantigens with tetramer staining, and established the Co-HA system, a single-plasmid system coexpressing patient human leukocyte antigen (HLA) and antigen, to detect the immunogenicity of neoantigens and verify new dominant hepatocellular carcinoma (HCC) neoantigens.

METHODS

First, we enrolled 14 patients with HCC for next-generation sequencing for variation calling and predicting potential neoantigens. Then, the Co-HA system was established. To test the feasibility of the system, we constructed target cells coexpressing HLA-A*11:01 and the reported KRAS G12D neoantigen as well as specific T-cell receptor (TCR)-T cells. The specific cytotoxicity generated by this neoantigen was shown using the Co-HA system. Moreover, potential HCC-dominant neoantigens were screened out by tetramer staining and validated by the Co-HA system using methods including flow cytometry, enzyme-linked immunospot assay and ELISA. Finally, antitumor test in mouse mode and TCR sequencing were performed to further evaluate the dominant neoantigen.

RESULTS

First, 2875 somatic mutations in 14 patients with HCC were identified. The main base substitutions were C>T/G>A transitions, and the main mutational signatures were 4, 1 and 16. The high-frequency mutated genes included HMCN1, TTN and TP53. Then, 541 potential neoantigens were predicted. Importantly, 19 of the 23 potential neoantigens in tumor tissues also existed in portal vein tumor thrombi. Moreover, 37 predicted neoantigens restricted by HLA-A*11:01, HLA-A*24:02 or HLA-A*02:01 were performed by tetramer staining to screen out potential HCC-dominant neoantigens. HLA-A*24:02-restricted epitope 5'-FYAFSCYYDL-3' and HLA-A*02:01-restricted epitope 5'-WVWCMSPTI-3' demonstrated strong immunogenicity in HCC, as verified by the Co-HA system. Finally, the antitumor efficacy of 5'-FYAFSCYYDL-3'-specific T cells was verified in the B-NDG-B2m^tm1Fcrn^tm1(mB2m) mouse and their specific TCRs were successfully identified.

CONCLUSION

We found the dominant neoantigens with high immunogenicity in HCC, which were verified with the Co-HA system.

Elevated Expression Levels of PC3-Secreted Microprotein (PSMP) in Prostate Cancer Associated With Increased Xenograft Growth and Modification of Immune-Related Microenvironment

Prostate cancer (PCa), especially metastatic PCa, is one of the main cancer types accounting for male mortality worldwide. Over decades, researchers have tried to search for effective curative methods for PCa, but many attempts have failed. The therapeutic failure of PCa is usually due to off-target or side effects; thus, finding a key molecule that could prevent PCa metastatic progression has become the most important goal for curing aggressive PCa. In this study, we collected hundreds of PCa tissues and serum and urine samples from patients to verify the upregulated expression of PC3-secreted microprotein (PSMP) in PCa tumor tissues with high Gleason scores. According to biopsy results, PSMP expression was found related to extraprostatic extension (EPE), contributing to PCa metastasis. Mechanistically, recombinant PSMP protein could promote the proliferation both in vitro and in vivo, and rhPSMP could promote epithelial–mesenchymal transition (EMT) of PC3 in vitro. Additionally, PSMP could also influence cytokine production in the xenograft model and monocyte migration and macrophage polarization in vitro. Our most important finding was that neutralizing antibodies against PSMP could suppress xenograft PC3 growth and promote the survival of PC3 metastatic mice model, providing an effective option to cure human PCa.

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.

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. Micro-CT, Hematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, real-time qPCR, ELISA, and flow cytometric 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 inflammation, alveolar bone resorption, osteoclast number, monocyte and macrophage infiltration. Prevention and treatment with CVC significantly reduced the severity of periodontitis, regardless of whether it was administered systemically or locally.

CONCLUSION

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.

Tracking the Helicobacter pylori Epidemic in Adults and Children in China

BACKGROUND

The Helicobacter pylori epidemic in China accounts for up to a third of gastric cancers worldwide. We aim to monitor the temporal and spatial dynamics of H. pylori infection in both adults and children across China.

MATERIALS AND METHODS

We developed a surveillance system consisting of a data collection component that harnessed survey reports in natural populations and an analysis component that accounted for the differences in survey time and location, population age structure, and H. pylori detection method. System outputs were estimates of the prevalence of H. pylori in adults and children (aged ≤ 14 years) presented at three hierarchical levels (regional, provincial, and prefectural).

RESULTS

The overall prevalence of H. pylori infection declined sharply in adults (63.3%, 52.5%, 43.4%, and 38.7%) and less sharply in children (23.1%, 26.1%, 16.0%, and 15.7%) in 1983-1999, 2000-2009, 2010-2014, and 2015-2019, respectively. The changes were asynchronous across regions, with the most marked declines in the Northwest, the Hong Kong-Macao-Taiwan region, and the East. We estimated that 457.6 million adults and 44.5 million children have been infected with H. pylori, with cross-province disparities in prevalence ranging from 24.3% to 69.3% among adults and 2.9% to 46.3% among children. In general, the risk level of gastric cancer increased as the prevalence of H. pylori increased. The correlation was statistically significant for both adult men (Spearman coefficient of correlation: 0.393, p = 0.0146) and women (0.470, p = 0.0029).

CONCLUSIONS

The tracking system would be important for the continuous and stratified tracking of the Helicobacter pylori epidemic across China and can be used to furnish an evidence base for the formulation of tailored prevention strategies.

PSMP, a novel chemotactic cytokine, triggers inflammatory Ly6ChiCCR2+ monocyte migration and promotes colitis in a CCR2-dependent manner

Chemokines plays a crucial role in the migration of leukocytes, which are involved in immune and inflammatory reactions with their receptors. To find novel chemotactic cytokines, we carried out genome-wide bioinformatics analysis and PBMC chemoattractant platform screen. Seven novel potential chemotactic cytokines were picked up, one of them was PC3-secreted microprotein (PSMP). The mature secreted PSMP was able to chemoattract human peripheral blood monocytes, lymphocytes and THP-1 cells. CCR2 was identified as a high-affinity receptor for PSMP by in vitro chemotaxis, calcium flux, receptor internalization, and radioligand-binding assays. Furthermore, we found that PSMP was extensively expressed at low levels in normal human tissues, but was significantly up-regulated in intestinal biopsies from patients with inflammatory bowel disease and mouse DSS-induced colitic tissue in the early stage prior to IL-6, TNF-α and CCL2 up-regulation. Moreover, the results showed that PSMP triggered inflammatory Ly6ChiCCR2+ monocyte migration from the circulation into the lamina propria in a CCR2-dependent manner and promoted the progression of inflammation. A PSMP neutralizing monoclonal antibody significantly mollified inflammation in a mouse DSS colitis model. Taken together, our study provides the first evidence that PSMP is a novel chemotactic cytokines whose receptor is CCR2 and PSMP plays a vital and irreplaceable role in triggering and promoting DSS colitis. Our finding not only reveals the function and regulating mechanism of PSMP, but also provides a promising therapeutic strategy for treating inflammatory bowel disease.

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.

A signature based on NKG2D ligands to predict the recurrence of hepatocellular carcinoma after radical resection

INTRODUCTION

Due to the high recurrence, the HCC prognosis remains poor. Yet, the biomarkers for predicting the recurrence of high-risk patients are currently lacking. We aimed to develop a signature to predict the recurrence of HCC based on NKG2D ligands.

METHODS

The multivariate Cox proportional hazards regression was used to select recurrence-related variables of NKG2D ligands in HCC patients from The Cancer Genome Atlas (TCGA). HCC patients from the OEP000321 dataset and Guilin cohort were used to validate the predictive signature. The mRNA expression of NKG2D ligands was measured by QRT-PCR. Immunohistochemistry analysis of HCC tissue microarray samples was used to identify the expression of NKG2D ligands.

RESULTS

In this study, NKG2D ligands expression in the mRNA and protein level was both abnormally expressed in HCC and associated with recurrence-free survival (RFS). Then, the recurrence-related variables of NKG2D ligands in HCC were selected by the multivariate Cox proportional hazards regression. Among the eight NKG2D ligands, MICA (HR = 1.347; 95% CI = 1.012-1.793; p = 0.041), ULBP3 (HR = 0.453; 95% CI = 0.231-0.889; p = 0.021) and ULBP5 (HR = 3.617; 95% CI = 1.819-7.194; p < 0.001) were significantly correlated with RFS in the TCGA-LIHC cohort. Then, the signature was constructed by the three NKG2D ligands. The predictive effectiveness of this signature was also validated in the OEP000321 dataset and Guilin cohort. Further, HCC patients were classified into low-risk and high-risk subgroups by the predictive score. Compared with the low-risk group, the high-risk group had poor RFS in both training and validation cohorts. Importantly, compared with the low-risk patients with the G1-G2 stage, the levels of infiltrated NK-activated cells and NKG2D expression were both lower in the high-risk patients.

CONCLUSIONS

The signature based on MICA, ULBP3, and ULBP5 could predict HCC recurrence.

Bridging the Gap Between Imaging and Molecular Characterization: Current Understanding of Radiomics and Radiogenomics in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common malignancy worldwide and the third leading cause of cancer-related deaths. Imaging plays a crucial role in the screening, diagnosis, and monitoring of HCC; however, the potential mechanism regarding phenotypes or molecular subtyping remains underexplored. Radiomics significantly expands the selection of features available by extracting quantitative features from imaging data. Radiogenomics bridges the gap between imaging and genetic/transcriptomic information by associating imaging features with critical genes and pathways, thereby providing biological annotations to these features. Despite challenges in interpreting these connections, assessing their universality, and considering the diversity in HCC etiology and genetic information across different populations, radiomics and radiogenomics offer new perspectives for precision treatment in HCC. This article provides an up-to-date summary of the advancements in radiomics and radiogenomics throughout the HCC care continuum, focusing on the clinical applications, advantages, and limitations of current techniques and offering prospects. Future research should aim to overcome these challenges to improve the prognosis of HCC patients and leverage imaging information for patient benefit.