Yulian Jiao

Polymorphisms of KIRs Gene and HLA-C Alleles in Patients with Ankylosing Spondylitis: Possible Association with Susceptibility to the Disease

IntroductionAn emerging body of evidence is accumulating to suggest that killer cell immunoglobulin-like receptors (KIRs) and human leukocyte antigen (HLA) class I ligands contribute to the pathogenesis of diverse kinds of autoimmune diseases. However, the functional effects of their polymorphism remain largely unknown to date. Thus, the present study was undertaken to determine the association of the polymorphisms KIRs gene and HLA-C alleles with the susceptibility to ankylosing spondylitis (AS) by means of polymerase chain reaction/sequence-specific primers for genotyping KIRs from genomic DNA of 119 patients with AS together with 128 healthy donors as a control group.Results and DiscussionWe found that the frequencies of KIR3DS1 and KIR2DL5 were statistically significantly higher in the patient group than those in the control group (P = 0.016 and P = 0.003, respectively). Meanwhile, the percentage of patients, who were carrying two or more of the activating KIRs, was higher than that of control group. With respect to HLA-C alleles, individuals with AS showed an increased frequency of HLA-Cw02. If HLA-C was divided into group 1 or group 2 based on whether there was an asparagine or lysine present at position 80 of the alpha-chain, HLA-C group 2 was more common in subjects with AS compared to control subjects. The genotype 2DS1+/HLA-C lys80+ was more common in subjects with AS. Moreover, the CD69 expression, a NK activation marker, remarkably increased in patient with AS.ConclusionIn conclusions, this study suggests that KIR3DS1 may severe as AS susceptive genes to trigger continuous injury of arthrosis. The imbalance of activating and inhibitory KIR as well as HLA-C group 1 and group 2 may be the key factor, which influences the pathogenesis of AS. Moreover, KIR2DS1 might associate with the susceptibility of AS by influencing NK cell activity once group 2 HLA-C ligands are present.

Polymorphisms of KIR Gene and HLA-C Alleles: Possible Association with Susceptibility to HLA-B27-Positive Patients with Ankylosing Spondylitis

AbstractAccumulating evidences indicate that killer cell immunoglobulin-like receptors (KIRs) and their corresponding specific HLA-C ligands contribute to the pathogenesis of multiple autoimmune diseases via the modulation of natural killer (NK) cell and T cell functions. The present study was performed to investigate whether the polymorphism of KIR genes and HLA ligands associates with the susceptibility of ankylosing spondylitis (AS). Previous studies have demonstrated a strong association between HLA-B27 gene and the pathogenesis of AS. In this study, 115 unrelated HLA-B27-positive AS patients and 119 HLA-B27-positive healthy controls were recruited. Polymerase chain reaction using sequence-specific primers was used to determine the genotypes of KIR genes and HLA-C alleles. The results showed that the frequencies of KIR2DL1 and KIR2DL5 were significantly higher in the AS patient group than those in the control group (p = 0.012 and p = 0.009, respectively). Meanwhile, individuals with AS showed an increased frequency of HLA-Cw*08 (p = 0.001, pc  = 0.008) compared with that in controls. Our findings indicate that with the genetic background of HLA-B27, variation at the KIRs and their corresponding specific HLA-C ligands may influence the ability of NK cells and T cells to recognize and lyse targets in immune responses, which thereby contributes to pathogenesis of AS.

Inhibitory KIR and specific HLA-C gene combinations confer susceptibility to or protection against chronic hepatitis B.

Antiviral activity of natural killer (NK) cells is regulated partially through inhibitory and activating killer cell immunoglobulin-like receptors (KIR) interacting with human leukocyte antigen C (HLA-C) ligands. The highly polymorphic nature of HLA-C and KIR genes endows individuals with diverse HLA-C/KIR combinations, which may confer susceptibility to or protection against a certain challenge. We analyzed the genes encoding KIR receptors and HLA-C ligands and HLA-C/KIR combinations in patients with chronic hepatitis B and healthy subjects. We found that inhibitory receptor KIR2DL1 in combination with HLA-C2 ligand confers susceptibility to chronic hepatitis B (CHB), whereas inhibitory receptor KIR2DL3 or KIR2DL3 homozygote in the presence of HLA-C1C1 genotype shows protection against CHB. Our data reveal that inhibitory NK cell interactions are important in determining antiviral immunity and that distinct affinity inhibitory responses will exert different impact on the development of CHB.

Immune complexes activate human endothelium involving the cell-signaling HMGB1-RAGE axis in the pathogenesis of lupus vasculitis.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the formation of immune complexes (ICs), which contain a complex mixture of autoantigens nucleic acids, nucleic acids-associated proteins and corresponding autoantibodies. In SLE, ICs are deposited in multiple organs. Vasculopathy and vasculitis in SLE are typical complications and are associated with deposition of ICs on endothelium, endothelial activation and inflammatory cell infiltration. However, the effects of ICs on endothelial cells and the mechanisms involved remain unclear. In this study, we have demonstrated for the first time that ICs upregulated cell surface expression of the receptor for advanced glycation end products (RAGE), the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), increased the secretion of the chemokines interleukin 8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), the proinflammatoy cytokines interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α) and promoted the activation of the transcription factor NF-κB p65 in human endothelial cells (P<0.05). ICs also increased transendothelial migration of monocytes (P<0.05). One of the mechanisms underlying these activating effects of ICs on human endothelial cells involves cell signaling by high-mobility group box 1 protein (HMGB1)-RAGE axis, as these effects can be partially blocked by HMGB1 A-box, soluble RAGE (sRAGE), SB203580, PD98059, Bay 117082 (P<0.05) and co-treatment with these agents (P<0.05). In conclusion, ICs elicit proinflammatory responses in human endothelial cells and alter their function involving cellular signaling via the HMGB1-RAGE axis in the pathogenesis of SLE vasculitis.

Association of KIR Genotypes and Haplotypes with Susceptibility to Chronic Hepatitis B Virus Infection in Chinese Han Population

Killer immunoglobulin-like receptor (KIR) genes can regulate the activation of NK and T cells upon interaction with HLA class I molecules. Hepatitis B virus (HBV) infection has been regarded as a multi-factorial disorder disease. Previous studies revealed that KIRs were involved in HCV and HIV infection or clearance. The aim of this study was to explore the possibility of the inheritance of KIR genotypes and haplotypes as a candidate for susceptibility to persistent HBV infection or HBV clearance. The sequence specific primer polymerase chain reaction (SSP-PCR) was employed to identify the KIR genes and pseudogenes in 150 chronic hepatitis B (CHB) patients, 251 spontaneously recovered (SR) controls, and 412 healthy controls. The frequencies of genotype G, M, FZ1 increased in CHB patients compared with healthy control subjects. The frequency of genotype AH was higher in SR controls than that in both CHB patients and healthy controls. The carriage frequencies of genotype G and AH were higher; while, the frequencies of AF and AJ were lower in SR controls than those in healthy control subjects. The frequency of A haplotype was lower, whereas, the frequency of B haplotype was higher in CHB patients and SR controls than those in healthy controls. In healthy controls, haplotype 4 was found lower compared with that in CHB patients and SR controls and the frequency of haplotype 5 was higher in SR controls than that in other two groups. Based on these findings, it seems that the genotypes M and FZ1 are HBV susceptive genotypes; AH, on the other hand, may be protective genotypes that facilitate the clearance of HBV. It appears that the haplotype 4 is HBV susceptive haplotype, whereas, haplotype 5 may be the protective haplotype that facilitates the clearance of HBV.

Disparate distribution of activating and inhibitory killer cell immunoglobulin-like receptor genes in patients with systemic lupus erythematosus

The genes of killer cell immunoglobulin-like receptors (KIRs), which are involved in the activation of T cells and natural killer cells, are highly variable. In recent years, the role of KIRs in autoimmune diseases has received increasing attention. The present study was undertaken to determine the association of the polymorphism of KIR genes with the susceptibility to systemic lupus erythematosus (SLE). The polymorphism of KIR genes of 93 patients with SLE together with 123 healthy donors as the control group was determined by polymerase chain reaction with sequence-specific primers. Twenty-seven novel gene combinations were found. Genotypic frequencies of KIR2DL2 (p < 0.001) and KIR2DS1 (p < 0.001) were much higher in patients with SLE than in control subjects. Individuals with two and more than two activating KIR genes were found more frequently in patients than in control subjects (80.7% versus 66.7%, p = 0.022). The results suggest that a genetic disturbance between activating and inhibitory KIR genes may be one of the key factors underlying the pathogenesis of SLE.

Possible association of VISA gene polymorphisms with susceptibility to systemic lupus erythematosus in Chinese population

Virus-induced signaling adapter (VISA), an important adaptor protein linking both RIG-I and MDA-5 to downstream signaling events, may mediates the activation of NF kappaB and IRFs and the induction of type I IFN. As the evidence has showed that Toll-like receptors (TLRs), I-IFN and IFN-inducible genes contribute to the pathogenesis of systemic lupus erythematosus (SLE), the aim of the current study was to investigate the possible associations between the VISA gene and SLE. Four single nucleotide polymorphisms (SNPs), rs17857295, rs2326369, rs7262903, and rs7269320, in VISA gene were genotyped in 123 SLE patients and 95 healthy controls. Genotyping was performed using direct sequencing the purified PCR products. Associations were analyzed by using the chi-square test and Fisher’s exact test. Haplotype analysis was performed using haploview and PHASE2.1. None of the four SNPs was found to be associated with SLE. The four-SNPs haplotype analysis showed different effect between cases and controls. While the SNPs, rs17857295 and rs2326369, were found to be associated with the renal nephritis and arthritis of SLE patient, respectively. The SNPs rs7269320 showed associations with different manifestations. Our data reveal that polymorphisms in the VISA gene may be related to disease susceptibility and manifestations of SLE.

Possible association of decreased NKG2D expression levels and suppression of the activity of natural killer cells in patients with colorectal cancer

Natural-killer group 2 (NKG2), a natural killer (NK) cell receptor, plays a critical role in regulating NK cytotoxicity. In this study, we investigated the expression levels of natural killer group 2 member A (NKG2A) and natural killer group 2 member D (NKG2D) in NK cells as well as the regulatory function of NKG2D in patients with colorectal cancer (CRC). Sixty-two CRC patients and 32 healthy controls were enrolled in this study. The expression levels of NKG2A and NKG2D mRNA in peripheral blood mononuclear cells (PBMCs) were investigated using real-time PCR. Flow cytometry was performed to assay the levels of NKG2A and NKG2D proteins in NK cells. The levels of NKG2D mRNA in PBMCs in the patients were significantly lower than those in the controls [mean ± SD, 1.11±0.60 (CRC patients) vs. 1.65±0.71 (healthy controls); p<0.01], whereas the 2 groups showed no apparent difference in the levels of NKG2A mRNA (p>0.05). In addition, the patients showed significantly lower NKG2D levels in NK cells than the controls did (71.23%±8.31% [CRC patients] vs. 79.39%±5.58% [healthy controls]; p<0.01). However, we observed no distinct difference in the NKG2A expression levels in NK cells between the 2 groups (p>0.05). Notably, blockage of NKG2D signaling with anti-NKG2D antibodies ex vivo resulted in decreased cytotoxicity and CD107a degranulation. Our data revealed that the decrease in NKG2D expression levels may have been associated with suppression of NK cell activity in CRC patients.

Estrogen promotes B cell activation in vitro through down-regulating CD80 molecule expression

Estrogen is the main female hormone of women. It has diverse effects on cell growth, differentiation and homeostatic functions. Accumulated evidence has indicated that estrogen may regulate multiple immune functions and the immune status of women. However, there is little report on the effect of estrogen on mature B cell functions. In this study, we observed the effect of 17β-estradiol (E2) on the proliferation, apoptosis, antibody production and differentiation of splenic B cells of mice in vitro. Splenocytes of female BALB/c mice were isolated and cultured with E2. E2 treatments decreased the expression of CD80 molecule on splenic B cells but enhanced the total IgG antibody production of splenocyte, without promoting the differentiation of B cells to plasma cells. E2 protected splenic B cells from the serum-deficiency-induced apoptosis but had no influence on the proliferation of B cells. These results suggest that estrogen may promote the activity of B cells through down-regulating the expression of CD80 molecule on B cells.

A FKBP5 mutation is associated with Paget|[rsquo]|s disease of bone and enhances osteoclastogenesis

Paget’s disease of bone (PDB) is a common metabolic bone disease that is characterized by aberrant focal bone remodeling, which is caused by excessive osteoclastic bone resorption followed by disorganized osteoblastic bone formation. Genetic factors are a critical determinant of PDB pathogenesis, and several susceptibility genes and loci have been reported, including SQSTM1, TNFSF11A, TNFRSF11B, VCP, OPTN, CSF1 and DCSTAMP. Herein, we report a case of Chinese familial PDB without mutations in known genes and identify a novel c.163G>C (p.Val55Leu) mutation in FKBP5 (encodes FK506-binding protein 51, FKBP51) associated with PDB using whole-exome sequencing. Mutant FKBP51 enhanced the Akt phosphorylation and kinase activity in cells. A study of osteoclast function using FKBP51V55L KI transgenic mice proved that osteoclast precursors from FKBP51V55L mice were hyperresponsive to RANKL, and osteoclasts derived from FKBP51V55L mice displayed more intensive bone resorbing activity than did FKBP51WT controls. The osteoclast-specific molecules tartrate-resistant acid phosphatase, osteoclast-associated receptor and transcription factor NFATC1 were increased in bone marrow-derived monocyte/macrophage cells (BMMs) from FKBP51V55L mice during osteoclast differentiation. However, c-fos expression showed no significant difference in the wild-type and mutant groups. Akt phosphorylation in FKBP51V55L BMMs was elevated in response to RANKL. In contrast, IκB degradation, ERK phosphorylation and LC3II expression showed no difference in wild-type and mutant BMMs. Micro-CT analysis revealed an intensive trabecular bone resorption pattern in FKBP51V55L mice, and suspicious osteolytic bone lesions were noted in three-dimensional reconstruction of distal femurs from mutant mice. These results demonstrate that the mutant FKBP51V55L promotes osteoclastogenesis and function, which could subsequently participate in PDB development.