Alleviation of murine allergic rhinitis by C19, a C-terminal peptide of chemokine-like factor 1 (CKLF1)

Role of chemokine-like factor 1 as an inflammatory marker in diseases

Immunoinflammatory mechanisms have been incrementally found to be involved in the pathogenesis of multiple diseases, with chemokines being the main drivers of immune cell infiltration in the inflammatory response. Chemokine-like factor 1 (CKLF1), a novel chemokine, is highly expressed in the human peripheral blood leukocytes and exerts broad-spectrum chemotactic and pro-proliferative effects by activating multiple downstream signaling pathways upon binding to its functional receptors. Furthermore, the relationship between CKLF1 overexpression and various systemic diseases has been demonstrated in both in vivo and in vitro experiments. In this context, it is promising that clarifying the downstream mechanism of CKLF1 and identifying its upstream regulatory sites can yield new strategies for targeted therapeutics of immunoinflammatory diseases.

Chemokines and chemokine receptors in allergic rhinitis: from mediators to potential therapeutic targets

Allergic rhinitis (AR) is an immune-mediated inflammatory condition characterized by immune cell infiltration of the nasal mucosa, with symptoms of rhinorrhea, sneezing, nasal obstruction, and itchiness. Currently, common medication for AR is anti-inflammatory treatment including intranasal steroids, oral, or intranasal anti-histamines, and immunotherapy. These strategies are effective to the majority of patients with AR, but some patients under medication cannot achieve symptom relieve and suffer from bothersome side effects, indicating a demand for novel anti-inflammatory treatment as alternatives. Chemokines, a complex superfamily of small, secreted proteins, were initially recognized for their chemotactic effects on various immune cells. Chemokines constitute both physiological and inflammatory cell positioning systems and mediate cell localization to certain sites via interaction with their receptors, which are expressed on responding cells. Chemokines and their receptors participate in the sensitization, early phase response, and late phase response of AR by promoting inflammatory cell recruitment, differentiation, and allergic mediator release. In this review, we first systemically summarize chemokines and chemokine receptors that are important in AR pathophysiology and then discuss potential strategies targeting chemokines and their receptors for AR therapy.

Overexpressed CMTM6 Improves Prognosis and Associated With Immune Infiltrates of Ovarian Cancer

Ovarian cancer (OV) is an epithelial malignancy that intrigues people for its high mortality and lack of efficient treatment. Chemokine-like factor (CKLF)–like MARVEL transmembrane domain containing 6 (CMTM6) can be observed in various cancers, but its part in OV remains little known. Hence, the prognostic value and underlying mechanism of CMTM6 in OV were preliminarily evaluated. Here, we determined that CMTM6 expression was higher than that in normal controls. However, the upregulation of CMTM6 was associated with better prognosis. GSEA results suggested that CMTM6 is involved in the immune-related and metabolism-related pathways. GO/KEGG analysis of CMTM6 coexpressed genes was performed to survey the possible regulatory roles of CMTM6 in OV. Subsequently, CMTM6 expression was positively correlated with the infiltration levels of immune cells and the expression of diverse immune cell marker sets. Importantly, CMTM6 may influence prognosis partially by regulating immune infiltration in OV. Last, copy number variations (CNVs) and DNA methylation might prompt the abnormal CMTM6 expression in OV. In conclusion, CMTM6 can serve as a novel prognostic biomarker in patients with OV.

Inhibition of CKLF1 ameliorates hepatic ischemia-reperfusion injury via MAPK pathway

BACKGROUND

Hepatic ischemia/reperfusion (I/R) injury is a major complication of liver resection or transplantation. However, the mechanism underlying hepatic I/R injury remains obscure. The aim of the present study was to investigate the role of Chemokine-like factor 1 (CKLF1) in hepatic I/R injury.

METHODS

Rats were subjected to 70% hepatic ischemia for 90 min, followed by 6, 12, 24, 48 and 96 h of reperfusion. The expression of CKLF1 was measured by real-time PCR and western blot. The effect of C19, an antagonism peptide of CKLF1, on hepatic I/R injury was investigated.

RESULTS

After subjected to 70% hepatic ischemia and reperfusion, the ALT and AST were increased. H&E results showed serious liver damage. The mRNA and protein levels of CKLF1 expression were upregulated during hepatic I/R. Immunohistochemistry staining results showed that neutrophil infiltration was increased in the ischemia lobe. MPO activity was significantly higher post reperfusion. TNF-α and IL-1β were upregulated during hepatic I/R. C19 administration significantly reduced the level of ALT and AST, decreased the necrosis area of liver tissue. Furthermore, C19 treatment inhibited neutrophil infiltration and reduced MPO activity. Meanwhile, C19 decreased the expression of TNF-α and IL-1β. The phosphorylation of P38, JNK were inhibited by C19 treatment.

CONCLUSION

CKLF1 was upregulated during hepatic I/R. Inhibiting CKLF1 by C19, an antagonism peptide of CKLF1, could alleviate hepatic I/R injury, reduce neutrophil infiltration, decrease inflammatory response. The protective effect of C19 may related to MAPK signaling pathway.

Chemokine-like factor-like MARVEL transmembrane domain-containing family in autoimmune diseases

The chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTM) is widely expressed in the immune system. Abnormal expression of CMTM is associated with the development of various diseases. This article summarizes the relevant research on the role of the CMTM family in immune disorders. This information will increase our understanding of pathogenesis and identify promising targets for the diagnosis and treatment of autoimmune diseases. The CMTM family is highly expressed in peripheral blood mononuclear cells. CKLF1 may be involved in the development of arthritis through its interaction with C-C chemokine receptor 4. CKLF1 is associated with the pathogenesis of lupus nephritis and psoriasis. Both CMTM4 and CMTM5 are associated with the pathogenesis of systemic lupus erythematosus. CMTM1, CMTM2, CMTM3, and CMTM6 play a role in rheumatoid arthritis, systemic sclerosis, Sjögren syndrome, and anti-phospholipid syndrome, respectively. The CMTM family has been implicated in various autoimmune diseases. Further research on the mechanism of the action of CMTM family members may lead to the development of new treatment strategies for autoimmune diseases.

Chemokine-like factor 1: A promising therapeutic target in human diseases

IMPACT STATEMENT

CKLF1, a recently identified chemokine, has been reported by a number of studies to play important roles in quite many diseases. However, the potential pathways that CKLF1 may be involved are not manifested well yet. In our review, we showed the basic molecular structure and major functions of this novel chemokine, and implication in human diseases, such as tumors. To attract more attention, we summarized its signaling pathways and clearly present them in a set of figures. With the overview of the experimental trial of CKLF1-targeting medicines in animal models, we hope to provide a few important insights about CKLF1 to both medical researchers and pharmacy.

IMM-H004 therapy for permanent focal ischemic cerebral injury via CKLF1/CCR4-mediated NLRP3 inflammasome activation

Chemokine-like factor 1 (CKLF1) is a potential target for ischemic stroke therapy. The NOD-like receptor protein 3 (NLRP3) inflammasome has been postulated to mediate inflammatory responses during ischemic/reperfusion (I/R) injury. The compound IMM-H004 is a novel coumarin derivative that can improve cerebral I/R injury. This study aims to investigate the effects of IMM-H004 on ischemia stroke injury and further elucidate the molecular mechanisms. The standard pMCAO model of focal ischemia was used in this paper. Drugs were administered at 6 hours after ischemia, and behavioral assessment, euthanasia, and outcome measures were evaluated at 9 hours after ischemia. The effects of IMM-H004 on ischemic stroke injury were determined using 2,3,5-triphenyltetrazolium chloride (TTC) staining, behavioral tests, enzyme-linked immunosorbent assay (ELISA), and Nissl staining. Immunohistologic staining, immunofluorescence staining, quantitative RT-PCR (qPCR), western blotting, and coimmunoprecipitation (CO-IP) assays were used to elucidate the underlying mechanisms. IMM-H004 treatment provided significant protection against ischemia stroke through a CKLF1-dependent anti-inflammatory pathway in rats. IMM-H004 downregulated the amount of CKLF1 binding with C-C chemokine receptor type 4, further suppressing the activation of NLRP3 inflammasome and the following inflammatory response, ultimately protecting the ischemic brain. This preclinical study established the efficacy of IMM-H004 as a potential therapeutic medicine for permanent cerebral ischemia. These results support further efforts to develop IMM-H004 for human clinical trials in acute cerebral ischemia, particularly for patients who are not suitable for reperfusion therapy.

IMM-H004 Protects against Cerebral Ischemia Injury and Cardiopulmonary Complications via CKLF1 Mediated Inflammation Pathway in Adult and Aged Rats

(1) Background: Chemokine-like factor 1 (CKLF1) is a chemokine with potential to be a target for stroke therapy. Compound IMM-H004 is a novel coumarin derivative screened from a CKLF1/C-C chemokine receptor type 4 (CCR4) system and has been reported to improve cerebral ischemia/reperfusion injury. This study aims to investigate the protective effects of IMM-H004 on cerebral ischemia injury and its infectious cardiopulmonary complications in adult and aged rats from the CKLF1 perspective. (2) Methods: The effects of IMM-H004 on the protection was determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining, behavior tests, magnetic resonance imaging (MRI) scans, enzyme-linked immunosorbent assay (ELISA), Nissl staining, histo-pathological examination, and cardiopulmonary function detection. Immunohistological staining, immunofluorescence staining, quantitative real-time PCR (qPCR), and western blotting were used to elucidate the underlying mechanisms. (3) Results: IMM-H004 protects against cerebral ischemia induced brain injury and its cardiopulmonary complications, inhibiting injury, and inflammation through CKLF1-dependent anti-inflammation pathway in adult and aged rats. IMM-H004 downregulates the amount of CKLF1, suppressing the followed inflammatory response, and further protects the damaged organs from ischemic injury. (4) Conclusions: The present study suggested that the protective mechanism of IMM-H004 is dependent on CKLF1, which will lead to excessive inflammatory response in cerebral ischemia. IMM-H004 could also be a therapeutic agent in therapy for ischemic stroke and cardiopulmonary complications in the aged population.

Study of the functional mechanisms of osteopontin and chemokine-like factor 1 in the development and progression of abdominal aortic aneurysms in rats

The aim of the study was to investigate the functional mechanisms of osteopontin (Opn) and chemokine-like factor 1 (Cklf1) during the development and progression of abdominal aortic aneurysms (AAA) in rats. Healthy adult Sprague-Dawley rats (n=30) were randomly divided into the AAA, control and sham groups (10 rats/group) and experimental rat models of AAA were generated by enzyme perfusion in abdominal aorta for 30 min. The AAA formation was assessed by measuring the aortal diameter and hematoxylin and eosin staining as well as specific staining to detect the structural changes of the aorta and inflammatory cell infiltration. Immunohistochemistry, western blot analysis and statistical analysis were also performed to examine the expression levels of Opn, Cklf1 and matrix metalloproteinase (MMP)-2 in the arterial tissue. Rat models of AAA were successfully established by protease perfusion. After perfusion, the diameter expansion rate of abdominal aorta was significantly higher (P<0.01) compared to controls, elastin present at the middle layer was significantly reduced and inflammatory cell infiltration was significantly higher in AAA rats. The expression of Opn, Cklf1 and MMP-2 in the AAA group was significantly increased compared to the control group (P<0.05) as revealed by immunohistochemical staining. The western blot analysis revealed that, the expression levels of Opn, Cklf1 and MMP-2 in the AAA group were significantly higher than the sham and control groups (P<0.01). We also found that the expression of Opn and MMP-2 was positively correlated. In conclusion, in rat models of AAA, Opn and Cklf1 function synergistically to upregulate the expression of MMP-2, causing accelerated degradation of extracellular matrix and eventually leading to the development and progression of AAA.

Therapeutic Effect of Histone Deacetylase Inhibitor, Sodium Butyrate, on Allergic Rhinitis In Vivo

Despite the well-documented therapeutic effects of histone deacetylase inhibitor (HDACi) on various diseases, including arthritis and asthma, the therapeutic effect of HDACi on allergic rhinitis remains unmentioned in the literature. This study investigated the therapeutic effect of sodium butyrate (SoB), a form of HDACi, on mice with allergic rhinitis. The results showed that the expression levels of histone deacetylase 1 (HDAC1), histone deacetylase 3 (HDAC3), and thymic stromal lymphopoietin (TSLP) were significantly upregulated in mice with allergic rhinitis, whereas H3 acetylation at lysine 9 (H3AcK9) was decreased. The intranasal application of SoB inhibited the expression levels of TSLP levels and upregulated the expression of H3AcK9 in a mouse model of allergic rhinitis. Furthermore, SoB treatment significantly decreased the increased levels of ovalbumin-specific IgE and improved clinical symptoms and nasal mucosa epithelial morphology in the mouse model of allergic rhinitis. In addition, we further demonstrated that SoB treatment significantly increased the serum levels of IL-2 and IFN-γ and decreased the serum levels of IL-4 and IL-10, correcting the Th1/Th2 imbalance in the mouse model of allergic rhinitis. Taken together, our study suggests that SoB has the potential to treat allergic rhinitis.

CMTM4 is frequently downregulated and functions as a tumour suppressor in clear cell renal cell carcinoma

BACKGROUND

Chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTM) is a gene family involved in multiple malignancies. CMTM4 is a member of this family and is located at chromosome 16q22.1, a locus that harbours a number of tumour suppressor genes. It has been defined as a regulator of cell cycle and division in HeLa cells; however, its roles in tumourigenesis remain poorly studied.

METHODS

An integrated bioinformatics analysis based on the array data from the GEO database was conducted to view the differential expression of CMTM4 across multiple cancers and their corresponding control tissues. Primary clear cell renal cell carcinoma (ccRCC) and the paired adjacent non-tumour tissues were then collected to examine the expression of CMTM4 by western blotting, immunohistochemistry, and quantitative RT-PCR. The ccRCC cell lines A498 and 786-O and the normal renal tubular epithelial cell line HK-2 were also tested for CMTM4 expression by western blotting. Cell Counting Kit-8 (CCK-8) and viable cell counting assays were used to delineate the growth curves of 786-O cells after CMTM4 overexpression or knockdown. Wound healing and transwell assays were performed to assess the cells' ability to migrate. The effects of CMTM4 on cellular apoptosis and cell cycle progression were analysed by flow cytometry, and cell cycle hallmarks were detected by western blotting and RT-PCR. The xenograft model in nude mice was used to elucidate the function of CMTM4 in tumourigenesis ex vivo.

RESULTS

By omic data analysis, we found a substantial downregulation of CMTM4 in ccRCC. Western blotting then confirmed that CMTM4 was dramatically reduced in 86.9 % (53/61) of ccRCC tissues compared with the paired adjacent non-tumour tissues, as well as in the 786-O and A498 ccRCC cell lines. Restoration of CMTM4 significantly suppressed 786-O cell growth by inducing G2/M cell cycle arrest and p21 upregulation, and cell migration was also inhibited. However, knockdown of CMTM4 led to a completely opposite effect on these cell behaviours. Overexpression of CMTM4 also markedly inhibited the tumour xenograft growth in nude mice.

CONCLUSIONS

CMTM4 is downregulated and exhibits tumour-suppressor activities in ccRCC, and could be exploited as a target for ccRCC treatment.

Chemokine-like factor 1-derived C-terminal peptides induce the proliferation of dermal microvascular endothelial cells in psoriasis

Psoriasis is an inflammatory disease characterized by the abnormal proliferation of skin cells, including dermal microvascular endothelial cells. Recently, chemokine-like factor 1 (CKLF1) was found to participate in the local inflammation and cell proliferation. To explore its role in the pathogenesis of psoriasis, the expression of both CKLF1 and its receptor (CCR4) was determined in the psoriatic lesions. Also, the effect of the C-terminal peptides (C19 and C27) of CKLF1 on the proliferation of human umbilical vein endothelial cells was studied in vitro. By immunohistochemistry and immunofluorescence, the expression of both CKLF1 and CCR4 was determined in the psoriatic lesions. The effect of C-terminal peptides on human umbilical vein endothelial cells (HUVECs) was studied in vitro by the evaluation of cell proliferation and apoptosis. The in vivo assessment was performed accordingly through the subcutaneous injection peptides on BALB/c mice. The results showed that, by immunohistochemistry, both CKLF1 and CCR4 were increasingly expressed in psoriatic lesions as compared to normal skins. Moreover, the primary umbilical vein endothelial cells exhibited higher proliferation ratio under the C19 or C27 stimulation, which was even enhanced by the addition of psoriatic sera or TNF-α. Furthermore, the enhancement of peptide simulation was accompanied with the activation of ERK1/2-MAPKs pathway. In addition, such effect of C19 and C27 was mirrored by the hyperproliferation of cutaneous microvessels in BALB/c mice that were subcutaneously injected with the two peptides. Therefore, we concluded that CKLF1 plays a role in the pathogenesis of psoriasis by promoting the proliferation of microvascular endothelial cells that possibly correlates with ERK1/2-MAPKs activation.

Chemokine-like factor 1 (CLFK1) is over-expressed in patients with atopic dermatitis

Background: Human chemokine-like factor 1 (CKLF1), a recently discovered chemokine, has a broad spectrum of biological functions in immune-mediated diseases. It is highly expressed on Th2 lymphocytes and is a functional ligand for human CCR4. CKLF1 has a major role in the recruitment and activation of leucocytes, which plays an important role in the pathogenesis of allergic diseases. The present study was designed to determine the expression of CKLF1 in skin and serum in patients with atopic dermatitis (AD).

Methods: The CKLF1 protein expression in skin lesion was analyzed by immunohistochemistry and ELISA. The mRNA expression of CKLF1 in skin lesion was detected by Real-time PCR. The serum levels of CKLF1, IgE, eotaxin, IL-4, IL-5, and IL-13 were measured by ELISA.

Results: Histopathological changes in the skin of AD patients showed local inflammation with epidermal thickening and significant inflammatory cellular infiltration. Immunohistochemistry results demonstrated that CKLF1-staining positive cells were located in the epidermal and dermis, and that the CKLF1 expression in AD patients was significantly higher than that in normal control. The CKLF1 mRNA expression in AD patients was significantly higher than that in healthy controls. Serum CKLF1 and IgE levels were significantly increased in AD patients, as were the serum levels of IL-4, IL-5, IL-13 and eotaxin.

Conclusions: Both CKLF1 protien and mRNA levels are overexpressed in the skin lesion of AD patients, along with an increase in serum CKLF1 level, indicating that CKLF1 may play an important role in the development of atopic dermatitis.

In vivo intranasal anti-CD23 treatment inhibits allergic responses in a murine model of allergic rhinitis

Although CD23-dependent transcytosis of IgE and IgE-derived immune complexes across respiratory epithelial cells is likely to play a pivotal role in the initiation and development of airway allergic inflammation, there is currently a lack of physiological support for this phenomena to suggest that the targeting of CD23 could be used as a means of therapeutic intervention. The present study was designed to detect the CD23 expression in the nasal mucosa of allergic rhinitis (AR) murine model by immunohistochemistry and western blotting, and to investigate whether intranasal anti-CD23 treatment could inhibit allergen-induced upper airway inflammation in the AR model. This is the first report to show that CD23 was constitutively expressed in murine nasal epithelial cells, and its expression was significantly up-regulated in the AR murine model. In vivo, the up-regulation of CD23 expression was correlated with increased serum IL-4 levels. Following intranasal anti-CD23 treatment, nasal symptoms were alleviated and histopathologic examination showed a significant decrease in eosinophilic infiltration. Meanwhile, ELISA analysis showed levels of serum leukotriene C4 (LTC4), eosinophil cation protein (ECP), ovalbumin (OVA)-specific IgE and IL-4 also significantly decreased, as were LTC4 and OVA-specific IgE in the nasal lavage fluid. Furthermore, Western blotting analysis showed that ECP expression in the nasal mucosa was down-regulated. Finally, flow cytometric analysis revealed anti-CD23 treatment inhibited Th2 cell responses. These results indicate that intranasal anti-CD23 treatment can reduce allergic responses in a murine model of allergic rhinitis.

Antagonistic effect of C19 on migration of vascular smooth muscle cells and intimal hyperplasia induced by chemokine-like factor 1

A chemokine-like factor 1 (CKLF1) is a recently discovered chemokine with broad-spectrum biological functions in inflammation and autoimmune diseases. C19 as a CKLF1's C-terminal peptide has been reported to exert inhibitory effects in a variety of diseases. However, the roles of CKLF1 and C19 on vascular smooth muscle cell (VSMC) migration and neointima formation still remain elusive. The effects of CKLF1 and C19 on VSMC migration and neointimal formation were investigated in cultured VSMCs and balloon-injured rat carotid arteries based on techniques including adenovirus-induced CKLF1 overexpression, gel based perivascular administration of C19, Boyden chamber, scratch-wound assay, real-time PCR, western blot and immunohistochemical analysis. CKLF1 was noticed to accumulate preferentially in neointima after the injury and colocalize with VSMCs. Luminal delivery of CKLF1 adenovirus to arteries exacerbated intimal thickening while perivascular administration of C19 to injured arteries attenuated this problem. In cultured primary VSMCs, CKLF1 overexpression up-regulated VSMC migration, which was down-regulated by C19. These data suggest that CKLF1 has a pivotal role in intimal hyperplasia by mediating VSMC migration. C19 was demonstrated to inhibit CKLF1-mediatated chemotaxis and restenosis. Thus further studies on C19 may provide a new treatment perspective for atherosclerosis and post-angioplasty restenosis.