Molecular cloning and expression of mouse homologue of SFA-1/PETA-3 (CD151), a member of the transmembrane 4 superfamily

Genetic background influences pig responses to porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome virus (PRRSV) is a highly infectious and economically significant virus that causes respiratory and reproductive diseases in pigs. It results in reduced productivity and increased mortality in pigs, causing substantial economic losses in the industry. Understanding the factors affecting pig responses to PRRSV is crucial to develop effective control strategies. Genetic background has emerged as a significant determinant of susceptibility and resistance to PRRSV in pigs. This review provides an overview of the basic infection process of PRRSV in pigs, associated symptoms, underlying immune mechanisms, and roles of noncoding RNA and alternative splicing in PRRSV infection. Moreover, it emphasized breed-specific variations in these aspects that may have implications for individual treatment options.

Expression of cluster of differentiation 151 prior to and following transcatheter arterial chemoembolization therapy in patients with hepatocellular carcinoma and its association with clinicopathological characteristics

Cluster of differentiation (CD)151, a member of tetraspanin family, is considered to be the first tetraspanin to be associated with tumor metastasis. Previous studies in vivo, in vitro and in the clinic have demonstrated that CD151 is involved in tumor progression at different levels through interaction with integrins, growth factor receptors and matrix metalloproteinases. Transcatheter arterial chemoembolization (TACE) is widely recommended for the treatment of patients with advanced hepatocellular carcinoma (HCC) worldwide. It has been hypothesized that TACE may create a hypoxic-ischemic environment that increases the expression of tumor progression-associated factors, promotes the angiogenesis of HCC, and initiates the recurrence and metastasis of HCC. Whether TACE promotes HCC progression remains controversial and numerous studies have focused on the influence of TACE on a number of tumor progression-associated factors. In the present study, the expression of serum CD151 in patients with HCC prior to and following TACE and its association with clinicopathological characteristics was investigated. It was revealed that the expression level of CD151 at 5-7 days post-TACE was significantly increased compared with pre-TACE levels. Risk factors and protective factors associated with tumor progression following a single TACE procedure and 18 months of follow-up were also identified. Furthermore, the present study revealed that a pre-TACE CD151 level of >0.3247 ng/ml and a 5-7 days post-TACE CD151 level of >0.3146 ng/ml revealed moderate sensitivity and specificity for predicting HCC progression following a single TACE procedure. The present study highlights CD151 as a useful marker in predicting the response to treatment and monitoring the disease course following TACE.

Deep sequencing and comprehensive expression analysis identifies several molecules potentially related to human poorly differentiated hepatocellular carcinoma

Hepatocellular carcinoma (HCC) that is graded histologically as poorly differentiated has a high recurrence, metastasis and poor prognosis. We sought to determine the regulatory mechanisms of HCC tumorigenesis and to identify molecules closely related to poorly differentiated HCC. High‐throughput sequencing was used to construct microRNA (miRNA) and mRNA expression profiles for poorly differentiated HCC tissues and adjacent tissues. Network analysis was carried out to study miRNA–target interactions. Integrating the miRNA and mRNA data of HCC with four tumor grades from The Cancer Genome Atlas (TCGA) portal enabled the identification of potential closely related molecules for early diagnosis of poorly differentiated HCC. Electronic validation of RNA‐seq data and survival analysis was also performed. In total, 1051 differentially expressed genes and 165 differentially expressed miRNAs were identified between HCC tumor and paired non‐tumorous tissue. Based on 3718 miRNA–target interactions, we established an miRNA–target interaction network; the target genes were mainly involved in bile acid biosynthesis and bile secretion. Integrating expression data of HCC from TCGA indicated that two proteins, TM4SF1 and ANXA2, are convincing indicators for initial diagnosis of poorly differentiated HCC. According to the survival analysis, three proteins, ANXA2, C8orf33 and IGF2BP3, were identified as being associated with the survival time of HCC patients. Moreover, we suggest that hsa‐miR‐1180 may be an effective biomarker for poorly differentiated HCC. Three molecules, TM4SF1, ANXA2 and C8orf33, are potential biomarkers for distinguishing poorly differentiated from well‐differentiated HCC.

β4 integrin is not essential for localization of hemidesmosome proteins plectin and CD151 in cerebral vessels

Objective:

In the central nervous system (CNS), β4 integrin is predominantly expressed by endothelial cells lining arterioles. As β4 integrin plays an essential role in epithelial tissues, organizing structural proteins into specialized adhesive structures called hemidesmosomes (HD), the aim of this study was to determine whether it plays a similar role in CNS endothelium.

Methods:

Dual-immunofluorescence was used to examine the relationship between β4 integrin expression and co-expression of the HD proteins plectin and CD151 in frozen sections of mouse brain, both under normoxic (control) conditions and following chronic mild hypoxia. The requirement of β4 integrin for the localization of HD proteins was examined in transgenic mice lacking β4 integrin expression specifically in endothelial cells (β4-EC-KO mice).

Results:

Immunofluorescence revealed that in the normal adult CNS, plectin and CD151 strongly co-localized with β4 integrin in arterioles. However, in the chronic mild hypoxia model, in which extensive cerebrovascular remodeling is observed, plectin and CD151 were strongly upregulated on all cerebral vessels, but surprisingly, in capillaries, this occurred in a β4 integrin-independent manner. Unexpectedly, absence of endothelial β4 integrin (in β4-EC-KO mice) had no impact on the expression level or distribution pattern of plectin and CD151 within stable or remodeling cerebral vessels.

Conclusions:

These results demonstrate that the HD proteins plectin and CD151 are closely associated with β4 integrin on arterioles in normal brain, and are strongly upregulated on remodeling blood vessels. However, unlike its described role in the epidermis, β4 integrin is not essential for localization or regulation of expression of plectin and CD151 in cerebral vessels.

CD151 in cancer progression and metastasis: a complex scenario

Originally identified as a molecular organizer of interacting proteins into tetraspanin-enriched microdomains, the tetraspanin CD151 has now been shown to be involved in tumour progression. Increasing evidence emerging from in vitro, in vivo and clinical analyses implicates this tetraspanin in supporting growth of various types of tumours at different levels. It affects both cell autonomous behavior and communication with neighboring cells and the microenvironment. CD151 regulates post-adhesion events, that is, cell spreading, migration and invasion including subsequent intravasation and formation of metastasis. Present on both neoplastic and endothelial cells, CD151 is engaged in promotion of tumour neovascularization. The molecular mechanism of CD151 in cancer is based on its ability to organize distribution and function of interacting proteins, ie, laminin-binding integrins (α3β1, α6β1 and α6β4), receptors for growth factors (HGFR, EGFR and TGF-β1R) and matrix metalloproteinases (MMP-7, MMP-2 and MMP-9), which indicates its importance in disease development. Results of clinical analyses of CD151 expression in different types of cancer and a large number of in vivo models demonstrate its impact on tumour growth and invasion and implicate CD151 as a valuable diagnostic and prognostic marker as well as a potential target for anti-cancer therapy.

The role of the tetraspanin CD151 in primary keratinocyte and fibroblast functions: implications for wound healing

Previous studies showed that CD151-null mice have a skin wound healing deficit. To gain an understanding of the role of CD151 in re-epithelialisation and dermal contraction, keratinocyte and fibroblast functions were assayed. Primary CD151-null keratinocytes displayed defective migration on Matrigel (a basement membrane equivalent) and laminin-332, the primary adhesion component of basement membranes, but not on collagen-I. Adhesion, spreading and proliferation were also deficient on laminin-332, but not collagen-I. The data suggest that loss of CD151 impairs the function of its primary interaction partners, integrin alpha3beta1- and/or alpha6beta4 which bind to laminin-332. Skin fibroblasts also produce CD151 mRNA. CD151-null fibroblasts migrated significantly faster on collagen I than wild type fibroblasts, confirming that they possess functional collagen receptors. However, no significant decrease in the ability of CD151-null fibroblasts to cause contraction in floating collagen gel assays in response to transforming growth factor beta-1 (TGF-beta1) or platelet derived growth factor (PDGF-BB) was observed, nor was there an effect on fibroblast adhesion or proliferation on collagen-I. The data implicate CD151 as a facilitator of laminin-332-mediated keratinocyte functions that impact on the re-epithelialisation process intrinsic to wound healing and further suggest a potential novel role for CD151 in fibroblast migration.

Role of CD151, A tetraspanin, in porcine reproductive and respiratory syndrome virus infection

Background

Porcine reproductive and respiratory syndrome virus (PRRSV) is a RNA virus causing respiratory and reproductive diseases in swine. The susceptibility for PRRSV varies between the different breeds of swine. In cell culture, PRRSV virus can be propagated in primary porcine alveolar macrophages and some African green monkey kidney cell lines, such as MARC-145 cells. Previous studies have shown that 3' untranslated region (UTR) RNAs of the arteriviruses play an important role in the replication of the virus through interactions with cellular proteins. To better understand the differences in the replication capability of PRRSV in different cell lines, we sought to identify the host cellular proteins interacting with PRRSV 3' UTR RNA. We constructed a cDNA library of MARC-145 cell line in lambda ZAP Express vector and screened the library with the positive sense 3' UTR RNA of PRRSV.

Results

We found that CD151, a host cellular protein, interacting with PRRSV 3' UTR RNA. The specificity of the interaction between CD151 and PRRSV 3' UTR RNA was examined by gel shift assay as well as North-Western hybridization. The transfection of CD151 expression clone into BHK-21 rendered these cells susceptible to PRRSV infection, and the transfection of siRNA against CD151 into MARC-145 significantly reduced the level of PRRSV infection. Also, anti-CD151 antibody treatment to MARC-145 completely blocked PRRSV infection.

Conclusion

Based on our results, we suggest that CD151 should cooperate in PRRSV infection in vitro in MARC-145 and BHK-21 cells.

Antagonist of secondary lymphoid-tissue chemokine (CCR ligand 21) prevents the development of chronic graft-versus-host disease in mice

The use of receptor antagonists for chemokines is an alternative approach to blocking chemokine actions and has the potential to provide novel therapeutics. We determined the receptor antagonist properties of murine N-terminally truncated secondary lymphoid tissue chemokine (SLC)/6Ckine/CCR ligand 21 analogs and evaluated the preventive effects of SLC antagonists on chronic graft-vs-host disease (GVHD) in a murine model by blocking the homing of donor CCR7-expressing T cells into the recipient's lymphoid organs. SLC analogs truncated >4 aa residues from the N terminus showed a loss of chemotaxis and Ca2+ influx of CCR7-expressing cells and also inhibited SLC-stimulated chemotaxis and SLC-induced Ca2+ influx completely. To determine whether SLC antagonist inhibits the development of chronic GVHD, chronic GVHD was induced by injecting DBA/2 spleen cells into (C57BL/6 x DBA/2) F1 mice. Total numbers of spleen cells and host B cells, serum levels of IgE, and of total IgG and IgG1 of anti-DNA Abs in SLC antagonist-treated GVHD mice were significantly lower than those in control PBS-treated GVHD mice. This was due to a reduction in the levels of activated donor CD4+ T cells and a decrease in IL-4 production, resulting in a reduction in the numbers of activated host B cells. Therefore, our results suggest that SLC antagonist has beneficial effects for the prevention of chronic GVHD.

CD151 enhances cell motility and metastasis of cancer cells in the presence of focal adhesion kinase

We have examined the role of the protein CD151 in cell motility, invasion and metastasis of cancer cells by using CD151-overexpressing cells prepared by transfection of CD151 cDNA into three cancer cell lines established from different origins; a human colon cancer RPMI4788, a human glioblastoma A172 and a human fibrosarcoma HT1080. Invasion into Matrigel and cell motility of all 3 CD151-overexpressing cancer cells were enhanced significantly when compared to control parental cells. Pulmonary metastasis of 2 metastatic CD151-overexpressing cancer cell lines, RPMI4788/CD151 and HT1080/CD151, was higher than that of control parental cells and was markedly inhibited by anti-CD151 monoclonal antibody (MAb), SFA1.2B4. To examine whether focal adhesion kinase (FAK) is associated with promotion of cell motility and invasion of cancer cells through CD151, we transfected human CD151 cDNA into FAK (+/+) or FAK (-/-) fibroblasts that were isolated from embryos in FAK-deficient mice and compared invasion into Matrigel and cell motility between each CD151-transfected cells and controls. The invasion into Matrigel and cell motility of CD151-transfected FAK (+/+) fibroblasts increased significantly above those of parental cells and were inhibited by anti-CD151 MAb, whereas those of CD151-transfected FAK (-/-) fibroblasts were not enhanced at all and were not blocked by anti-CD151 MAb. These findings indicate that the CD151 molecule enhances cell motility, invasion and metastasis of cancer cells and that FAK is needed for these events through CD151.

Enhancement of anti-tumor immunity by tumor cells transfected with the secondary lymphoid tissue chemokine EBI-1-ligand chemokine and stromal cell-derived factor-1alpha chemokine genes

Several new lymphocyte-specific chemokines, which attract naive and memory T cells, B cells, dendritic cells and natural killer cells, have been isolated. We have found evidence of the anti-tumor effects of 3 major lymphocyte-specific chemokines, secondary lymphoid tissue chemokine (SLC), EBI-1-ligand chemokine (ELC) and stromal cell-derived factor (SDF)-1alpha, in murine models (Meth A fibrosarcoma and HM-1 ovarian tumor). In both naive and immunized mice, tumors expressing SLC, ELC or SDF-1alpha showed delayed progression compared with control tumors. In mice immunized with tumor cells expressing 1 of these 3 chemokine genes, challenge with parental tumor cells resulted in slightly slower progression than in control mice, while in mice immunized with tumor cells transfected to co-express IL-2 or granulocyte-macrophage colony-stimulating factor (GM-CSF) as well as these chemokines, all tumors regressed. Furthermore, spleen cells from mice immunized with these "double-transfected" tumor cells exhibited higher proliferative responses and greater cytotoxic activity against parental tumor cells. These anti-tumor effects were associated with profound alterations in the leukocyte populations within the tumors and regional lymph nodes, and this was due to activation of type I T cell-dependent responses that produced high levels of IFN-gamma. These findings show that SLC, ELC and SDF-1alpha enhance anti-tumor immunity both systemically and locally and that these chemokines may be clinically useful, especially when combined with IL-2 and GM-CSF.

Increased chemokine receptor CCR7/EBI1 expression enhances the infiltration of lymphoid organs by adult T-cell leukemia cells

Adult T-cell leukemia (ATL) is characterized by infiltration of various tissues by circulating ATL cells, a finding often associated with a poor prognosis. Leukocyte migration from the circulation into tissues depends on integrin-mediated adhesion to the endothelium, and integrins are tightly regulated by several factors, such as chemokines. In this study, we focused on the interaction between chemokines and chemokine receptors on ATL cells to understand factors involved in ATL cell infiltration of lymphoid organs. We compared freshly isolated ATL cells from patients with and without lymphoid organ involvement for the expression of the chemokine receptor CCR7/EBI1, the functional receptor for secondary lymphoid-tissue chemokine (SLC), which is expressed at high levels by high endothelial venules of lymph nodes and Peyer's patches. Reverse transcriptase-polymerase chain reaction and flow cytometric analysis, using anti-CCR7 monoclonal antibody (CCR7.6B3), revealed that ATL cells from patients with lymphoid organ involvement expressed significantly more CCR7/EBI1 than control CD4+CD45RO+ T cells and ATL cells from patients without lymphoid organ involvement. Consequently, significantly more ATL cells from patients with lymphoid organ involvement than control CD4+CD45RO+ T cells and ATL cells from patients without lymphoid organ involvement adhered to surfaces coated with ICAM-1 and SLC or EBI1-ligand chemokine (ELC), another ligand for CCR7/EBI1, under static and flow conditions and migrated toward SLC or ELC at a low concentration (30 ng/ml). These findings suggest that increased CCR7/EBI1 expression plays a role in lymphoid organ infiltration of ATL cells. (Blood. 2000; 30-38)

Increased chemokine receptor CCR7/EBI1 expression enhances the infiltration of lymphoid organs by adult T-cell leukemia cells

Adult T-cell leukemia (ATL) is characterized by infiltration of various tissues by circulating ATL cells, a finding often associated with a poor prognosis. Leukocyte migration from the circulation into tissues depends on integrin-mediated adhesion to the endothelium, and integrins are tightly regulated by several factors, such as chemokines. In this study, we focused on the interaction between chemokines and chemokine receptors on ATL cells to understand factors involved in ATL cell infiltration of lymphoid organs. We compared freshly isolated ATL cells from patients with and without lymphoid organ involvement for the expression of the chemokine receptor CCR7/EBI1, the functional receptor for secondary lymphoid-tissue chemokine (SLC), which is expressed at high levels by high endothelial venules of lymph nodes and Peyer's patches. Reverse transcriptase-polymerase chain reaction and flow cytometric analysis, using anti-CCR7 monoclonal antibody (CCR7.6B3), revealed that ATL cells from patients with lymphoid organ involvement expressed significantly more CCR7/EBI1 than control CD4+CD45RO+ T cells and ATL cells from patients without lymphoid organ involvement. Consequently, significantly more ATL cells from patients with lymphoid organ involvement than control CD4+CD45RO+ T cells and ATL cells from patients without lymphoid organ involvement adhered to surfaces coated with ICAM-1 and SLC or EBI1-ligand chemokine (ELC), another ligand for CCR7/EBI1, under static and flow conditions and migrated toward SLC or ELC at a low concentration (30 ng/ml). These findings suggest that increased CCR7/EBI1 expression plays a role in lymphoid organ infiltration of ATL cells. (Blood. 2000; 30-38)

SFA-1/PETA-3 (CD151), a Member of the Transmembrane 4 Superfamily, Associates Preferentially with α5β1 Integrin and Regulates Adhesion of Human T Cell Leukemia Virus Type 1-Infected T Cells to Fibronectin

In this study we have analyzed the adhesion molecules associated with and the biologic function of SFA-1/PETA-3 (CD151) in human T cell leukemia virus type 1 (HTLV-1)-infected T cells and in freshly isolated adult T cell leukemia (ATL) cells using an anti-CD151 mAb. The anti-CD151 mAb coprecipitated α5β1 integrin from HTLV-1-infected T cells. Conversely, an anti-α5 integrin mAb coprecipitated CD151. The anti-CD151 mAb inhibited the adhesion of HTLV-1-infected T cells to fibronectin but did not have any effect on their adhesion to laminin, collagen type I, or collagen type IV. Moreover, antisense CD151 oligonucleotide-treated HTLV-1-infected T cells showed significant inhibition of adhesion to fibronectin. These findings showed that the CD151 molecule was associated with the α5β1 integrin molecule and that it enhanced α5β1 integrin-mediated adhesion to fibronectin. In addition, the expression levels of CD151, α4β1 integrin, and α5β1 integrin on ATL cells from lymph nodes of lymphoma-type ATL patients were significantly higher than those on circulating ATL cells from leukemia-type ATL patients. This suggests that the increased expression of these integrins may contribute to lymphoma formation through the adhesion of ATL cells to the extracellular matrix and dendritic cells, rather than contributing to transmigration.