MS4A6D promotes carrageenan-induced mouse foot pad swelling by activating NLRP3 inflammasome / 免疫学杂志

ABSTRACT

We here investigated the effect of MS4A6D(the membrane spanning 4-domain subfamily A(MS4A)superfamily protein 6D),one of the tetraspanins which specifically expresses on the membrane of macrophages,on carrageenan(CGN)-induced mouse foot pad swelling and its possible mechanism.Male C57BL/6 wild-type(WT)and various gene knockout(including Ms4a6d-/-,Nlrp3-/-,Casp-1-/-and IlR1-/-)mice were recruited and injected with 100 μl 1%CGN(w/v)and 20 μl CaCl2(50 mmol/L)to establish the foot pad swelling model,and then the severity of foot pad swelling in WT and gene knockout mice were compared.H&E staining was performed to investigate the pathological changes,and immunofluorescence was used to detect the infiltration of F4/80+ macrophages in the foot pad tissue.Finally,Western blot was used to determine the protein expression of NLRP3,IL-1 β,TNF-α and IL-6.Data showed that the combined injection of 100 μl 1%CGN(w/v)and 20 μl CaCl2(50 mmol/L)significantly promoted the swelling of foot pads,while the degree of foot pad swelling in Ms4a6d-/-mice was significantly lower than that in WT littermates(P<0.05);Significant tissue damage and inflammatory infiltration as well as necrotic lesions were observed in the WT foot pads,whereas,the degrees from Ms4a6d-/-foot pads showed significantly reduced;The protein levels of Caspase-1 and IL-1β in the foot pad tissue of the WT model were significantly higher than those of the Ms4a6d-/-groups;Compared with WT controls,the degree of foot pad swelling in Nlrp3-/-,Casp-1-/-,and IlR1-/-mice induced by 1%CGN(w/v)and CaCl2(50 mmol/L)were also significantly reduced(P<0.05).Taken together,MS4A6D promotes the activation of NLRP3 inflammasome in macrophages and induces IL-1β secretion,by thus deteriorates CGN-mediated swelling of mouse foot pads.