Expression Of TL1A And Its Ligand In Ulcerative Colitis Patient’s Colonic Mucosa

Ulcerative colitis (UC), one of the inflammatory bowel disease, is achronic non-specific easy-to-relapse inflammatory rectum and colon diseases,which main cause remains unknown. Nowadays, most researchers think thatUC is based on the genetic susceptibility, combined with multiple factors suchas environment, heredity, colonic mucosal inflammation-immune system andso on. Among them, more scientists suppose that immune system is the key ofpathogenesis.TNF ligand-related molecule-1A (TL1A) is a new member of tumornecrosis factor superfamily (TNFSF), which is a protein product ofTNFSF15/VEGI. It suggests that CD4+T cells increase activity in the colonicmucosa of people who suffer from IBD. Meanwhile the expression of TL1AmRNA in CD4+T cells is notably higher than normal. When TL1A combinesits receptor-death receptor3(DR3), they can activate nuclear factor-kappa B(NF-κB) pathway to cause inflammation and passing cell apoptosis signal. Onthe other hand, DcR3(Decoy receptor3), anther ligand to TL1A, can competeand inhibit DR3to TL1A, blocking apoptosis signal, but DcR3did not inhibitthe process of inflammation. Although DcR3itself can down-regulate someinflammation in autoimmune diseases, but most researchers think it has apro-inflammatory role in process of IBD.Matrix metalloproteinases (MMPs) are a class of proteolytic enzymesthat degrade extracellular matrix (ECM), involved in development of tissueinjury and repair process. MMP-2belongs to the MMPs in Gelatinasessubstances, mainly involved in basement membrane type IV collagenmetabolic process. When TL1A-DcR3-mediated intestinal inflammationingravescent, MMP-2expression upregulated, basement membranedecomposes and collagen deposition, UC-relatived intestinal fibrosis change started. In addition, interaction between TL1A and DcR3promoteshyperplasia and migration of human umbilical vein endothelial cell (HUVEC).In return, stimulated endothelial cells induce MMP-2mRNA expressionupregulated, and promotes endothelial cells to form new vessels,. All above,these procedures help tumor cells escape immunological surveillance fromorganism, which sets basements of UC-related intestinal fibrosis and even thedevelopment of canceration.Objective: To discuss the expression of TL1A and its change in colonicmucosa of UC patients, and provide a novel target for biological treatment toUC.Methods:(1) We collected the colonic mucosal biopsy samples of UCpatients who got a colonoscopy in the second hospital of Hebei MedicalUniversity. All the cases conformed to the standards of “the Consensus onInflammatory Bowel Disease Diagnosis and Treatment in China in2012”.Excluding cases of the standard: not stereotypes colitis, parental or othersystem disease of tuberculosis, merger of colorectal tumors, merger otherorigin tumors, during pregnancy or breast-feeding women, combined cardiachypertrophy, pathological findings sarcoidosis kind of meat tooth swollen,critical condition, severe cognitive impairment, mental disorders andend-stage patients of some diseases. Samples of the control group have beenpicked in those who were normal in both blood routine examination (bloodroutuine, biochemistry, erythrocyte sedimentation rate, C-reactive protein) innormal range and colonoscope or have purely single polyp without anydiseases.(2) Gather the data of patients including age, gender, race, course ofdisease, stool frequency and character, medication history, examination ofcolonoscopy (range and appearance) and laboratory tests (blood routine, stoolroutine, ESR, CRP), family history, individual history (smoke or not).(3)Dividing patients. According to H&E pathological dyeing: control group,inflammation group, UC-related intestinal fibrosis group and UC-relatedintestinal dysplasia group. Further subdivided according to the degree ofmucosal inflammation: control group, mild inflammation group, moderate inflammation group, severe inflammation group, UC-related intestinal fibrosisgroup and UC-related intestinal dysplasia group. According to Mayo grade:control group, mild activity group, moderate activity group, severe activitygroup. According to the examination of colonoscopy: control group, E1(rectum) group, E2(left colon) group, E3(widely colon) group. According toincidence: control group, early onset group and chronice relasing group.(5)Using H&E pathological dyeing to observe the pathological alteration of colon.Testing the expression level of TL1A, DcR3, NF-κB, MMP-2and their mRNAby immunohistochemistry (IHC), Western blot and real-time quantitativepolymerase chain reaction (RT-QPCR).Results:(1) TL1A, DcR3, NF-κB p65and MMP-2was positivelycorrelated with each other (P<0.01), and process of UC, involoing range,incidence types.(2) TL1A content with the UC process of its expression(P<0.01), with inflammatory action increased, the expression of TL1A alsoup-regulated. At stage of UC-related intestinal fibrosis, although TL1A wasover-expression in stenosis group than in inflammation group, but there wereno significant differences between them (P>0.05). At stage of UC-relateddysplasia, TL1A was over-expression in dysplasia group than in inflammationand stenosis group, but low expression in severe inflammation group (P<0.01).The expression of TL1A content aggravated degree of inflammatory activitywith Mayo score increased and UC lesions range expanded(P<0.01). TL1Aexpress in different incidence of type (P<0.01), compare to control group,expression in early onset group was up-regulated and more in chronice(P<0.01).(3) DcR3content with the UC process of its different expression(P<0.01), and its levels gradually increase with pathological grade (P<0.01).At stage of UC-related intestinal fibrosis, although DcR3was over-expressionin stenosis group than in inflammation group, but it was over-expression insevere inflammation group (P<0.01). The expression of DcR3contentaggravated degree of inflammatory activity with Mayo score increased andUC lesions range expanded(P<0.01). DcR3express in different incidence oftype (P<0.01), compare to control group, expression in early onset group was up-regulated and more in chronice (P<0.01).(4) NF-κB p65content with theUC process of its different expression (P<0.01), and its levels graduallyincrease with pathological grade (P<0.01). At stage of UC-related intestinalfibrosis, although NF-κB p65was over-expression in stenosis group than ininflammation group, but there were no significant differences between them(P>0.05)，and the expression of NF-κB were more in fibrosis group thanmoderate inflammation group but less in severe inflammation group. At stageof UC-related dysplasia, NF-κB p65was low expression than in severeinflammation group (P<0.01). The expression of NF-κB p65contentaggravated degree of inflammatory activity with Mayo score increased andUC lesions range expanded(P<0.01). NF-κB p65express in differentincidence of type (P<0.01), compare to control group, expression in earlyonset group was up-regulated and more in chronice (P<0.01).(5) MMP-2content with the UC process of its different expression (P<0.01), and its levelsgradually increase with pathological grade (P<0.01). At stage of UC-relatedintestinal fibrosis, MMP-2was over-expression in stenosis group than ininflammation group, but there were no significant differences between them(P>0.05). More, its expression was more up-regulated in stenosis group thanin moderate inflammation group (P<0.01) and down-regulated in severeinflammation group (P>0.05). At stage of UC-related dysplasia, MMP-2content in dysplasia group were more than stenosis group (P<0.01) andinflammation group (P<0.05), but low expression than in severe inflammationgroup (P<0.05). The expression of MMP-2content aggravated degree ofinflammatory activity with Mayo score increased and UC lesions rangeexpanded (P<0.01). MMP-2expressed in different incidence of type (P<0.01),compare to control group, expression of MMP-2in early onset group wereup-regulated and more in chronice (P<0.01).Conclusion: TL1A, DcR3, MMP-2and NF-κB p65were involving in theprocess of UC lesions, range, and incidence type and inflammation activity.All of them were positively correlated. The mechanism maybe related to therole of TL1A, as the initiation factor to UC incidence, bind DcR3and induce NF-κB pathway to transmit inflammatory singal. They also activate MMP-2todegradate ECM, collagen precipitation and angiogenesis.