A20 Haploinsufficiency Aggravates Transplant Arteriosclerosis in Mouse Vascular Allografts

Abstract

Background Inflammation is central to the pathogenesis of transplant arteriosclerosis (TA). We questioned whether physiologic levels of anti-inflammatory A20 influence TA severity. Methods We performed major histocompatibility complex (MHC) mismatched aorta to carotid artery interposition grafts, using wild type (WT) or A20 heterozygote (HET) C57BL/6 (H-2b) donors and BALB/c (H-2d) recipients, and conversely BALB/c donors and WT/HET recipients. We analyzed aortic allografts by histology, immunohistochemistry, immunofluorescence, and gene profiling (qPCR). We validated select in vivo A20 targets in human and mouse smooth muscle cell (SMC) cultures. Results We noted significantly greater intimal hyperplasia in HET vs. WT allografts, indicating aggravated TA. Inadequate upregulation of A20 in HET allografts after transplantation was associated with excessive NF-κB activation, gauged by higher levels of IκBα, p65, VCAM-1, ICAM-1, CXCL10, CCL2, TNF, and IL-6 (mostly localized to SMC). Correspondingly, cytokine-induced upregulation of TNF and IL-6 in human and mouse SMC cultures inversely correlated with A20 expression. Aggravated TA in HET vs. WT allografts correlated with increased intimal SMC proliferation, and a higher number of infiltrating IFNγ+ and Granzyme B+ CD4+ T cells and natural killer cells, and lower number of FoxP3+ regulatory T cells. A20 haploinsufficiency in allograft recipients did not influence TA. Conclusions A20 haploinsufficiency in vascular allografts aggravates lesions of TA by exacerbating inflammation, SMC proliferation, and infiltration of pathogenic T cells. A20 single nucleotide polymorphisms (SNPs) associating with lower A20 expression or function in donors of vascularized allografts may inform risk and severity of TA, highlighting the clinical implications of our findings.

Toll-Like Receptor-4 Signaling Drives Persistent Fibroblast Activation and Prevents Fibrosis Resolution in Scleroderma

“…62 In the absence of A20, mice spontaneously develop sclerodermatous skin changes, including thickened dermis and loss of dermal white adipose tissue, and show premature lethality due to widespread inflammation. 63 Deficiency of A20 in intestinal epithelial cells is associated with IBD, in myeloid cells causes joint inflammation, in dendritic cells causes colitis, in mast cells exacerbate inflammation, 64,65 in B cells autoimmunity but only in old mice, and in vascular allografts aggravate severity of transplant arteriosclerosis. [66][67][68][69] These observations highlight the diverse and cell type-, age-, and disease-specific functions of A20.…”

Analysis of the Clinical and Genetic Characteristics of 3 Cases of A20 Haploinsufficiency

“…(21) Jarosz-Gri ths HH 1,2,3 , Holbrook J 1,2,3 , Lara-Reyna S 1,2,3 , McDermott MF 1 .TNF receptor signalling in autoin ammatory diseases. Int Immunol.…”

“…2019 ; doi: 10.1093/intimm/dxz024. (22) Papadopoulou C 1,2 , Omoyinmi E 1,2 , Standing A 1,2 , Pain CE 3 Tables Table 1 patient1 patient2 patient3…”

Clinical characteristics and genetic analysis of 3 A20 Haploinsufficiency patients

“…A20 haploinsu ciency (HA20) is an autosomal dominant genetic disease caused by mutation of TNF-αinduced protein 3 (TNFAIP3) gene (5)(6)(7). The cause of this disease is insu cient production of A20 resulting in negative feedback inhibition of NF-kB signalling pathway.…”

“…Background A20 haploinsu ciency is an autosomal dominant hereditary disease caused by a pathological mutation in tumour necrosis factor (TNF)-α-induced protein 3 gene (1,2). As a result, production of nuclear factor (NF)-κB regulatory protein A20 encoded by TNFAIP3 gene is insu cient, and clinical signs resemble Behçet's disease (3,4). However, these clinical signs appear earlier in HA20, and the age of disease onset is most likely before 10, including recurrent appearance of painful oral, genital, and/or gastrointestinal ulcers.…”