Foxp3 expression in induced T regulatory cells derived from human umbilical cord blood vs. adult peripheral blood

Abstract

Foxp3 is essential for T regulatory cell (Treg) function. Broad complex-Tramtrack-Bric-a-brac domain (BTB) and Cap'n'collar (CNC) homology 1, transcription factor 2 (BACH2) stabilizes Treg immune homeostasis in murine studies. However, little is known regarding what role, if any, BACH2 may have in Foxp3 regulation in human-induced Treg (iTreg). We examined Foxp3 expression and regulation comparing iTreg differentiated from umbilical cord blood (UCB) vs. adult blood (AB) naive CD4 T-cells. Foxp3 expression was higher in UCB vs. AB-derived iTreg, and was sustained during 21-day expansion in vitro. The number of Foxp3 iTreg generated from UCB vs. AB naive CD4 T-cells was higher in iTreg differentiation conditions. In addition, UCB iTreg were more potent in suppressing T-cell proliferation compared to AB iTreg. Naive UCB CD4 T-cells highly expressed BACH2 protein compared to AB. Putative transcriptional BACH2 binding sites were identified at the Foxp3 promoter, using BACH2 consensus sequence. Cross-linking chromatin immunoprecipitation (ChIP) showed that BACH2 binds to the Foxp3 proximal promoter in UCB iTreg, but not AB iTreg. BACH2 was transcriptionally active, as shRNA-mediated BACH2 knockdown resulted in reduction of Foxp3 gene transcription in UCB CD4 T-cells. In summary, BACH2 serves to stabilize robust Foxp3 expression in UCB CD4 T-cell-derived iTreg.

Mesenchymal stromal cell mitochondrial transfer to human induced T-regulatory cells mediates FOXP3 stability

“…S1 a). UCB-derived naive CD4 + CD45RA + T cells were differentiated into iTreg in standard 4 day culture in TGF-β condition 16 . UCB FOXP3 + iTregs co-cultured with MSCs rendered a significantly higher percentage and absolute number of FOXP3 + iTregs compared to standard IL-2/media suspension culture condition 26 at day 14 and 21 and show similar viability (Fig.…”

“…BACH2 maintains stability and function of murine Treg 15 , 47 . We previously identified BACH2 is highly expressed in human UCB-derived iTreg and increases FOXP3 expression 16 . Additional studies have shown that SENP3 modulates BACH2 SUMOylation of and enhances iTreg stability in response to changing environmental conditions, particularly intracellular ROS 17 .…”

“…BACH2, a Broad-complex-tramtrack-Bric-a-Brac and Cap’n’collar homology 2 bZip transcription factor, has been shown to stabilize Treg Foxp3 expression in recent murine studies 14 , 15 . BACH2 has also been shown to regulate FOXP3 expression in human Umbilical Cord Blood (UCB) iTreg 16 . Further, murine studies identify SUMO specific protease 3 (SENP3) to be a critical regulator of Treg function by regulating the SUMOylation and nuclear localization of BACH2 17 .…”

T cell Tolerance in Early Life

“…Both human or mouse fetal/neonatal CD4 + T cells preferentially differentiate into induced Tregs (iTregs) when compared to adult CD4 + T cells ( 58 , 103 , 110 , 111 ). Inhibiting Lin28b in human fetal CD4 + T cells leads to let-7 upregulation and reduced Treg cell differentiation ( 112 ).…”

Recent Progress in Treg Biology and Transplant Therapeutics

“…Recipient peripheral blood is the primary source of T regs for ex vivo expansion and subsequent adoptive immunotherapy; however, reports utilizing umbilical cord blood-derived T regs are emerging [29,30], and West and colleagues report the intriguing prospect of using human thymus routinely removed during pediatric cardiothoracic surgery as a source of nT regs [31]. Numerous manuscripts addressing the technical aspects of clinical T reg manufacture including cryopreservation [32] and automation [33] have appeared.…”