A Thyroid Hormone Receptor/KLF9 Axis in Human Hepatocytes and Pluripotent Stem Cells

Abstract

Biological processes require close cooperation of multiple transcription factors that integrate different signals. Thyroid hormone receptors (TRs) induce Kr€ uppel-like factor 9 (KLF9) to regulate neurogenesis. Here, we show that triiodothyronine (T3) also works through TR to induce KLF9 in HepG2 liver cells, mouse liver, and mouse and human primary hepatocytes and sought to understand TR/KLF9 network function in the hepatocyte lineage and stem cells. Knockdown experiments reveal that KLF9 regulates hundreds of HepG2 target genes and modulates T3 response. Together, T3 and KLF9 target genes influence pathways implicated in stem cell selfrenewal and differentiation, including Notch signaling, and we verify that T3 and KLF9 cooperate to regulate key Notch pathway genes and work independently to regulate others. T3 also induces KLF9 in human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSC) and this effect persists during differentiation to definitive endoderm and hiPSC-derived hepatocytes. Microarray analysis reveals that T3 regulates hundreds of hESC and hiPSC target genes that cluster into many of the same pathways implicated in TR and KLF9 regulation in HepG2 cells. KLF9 knockdown confirms that TR and KLF9 cooperate to regulate Notch pathway genes in hESC and hiPSC, albeit in a partly cell-specific manner. Broader analysis of T3 responsive hESC/hiPSC genes suggests that TRs regulate multiple early steps in ESC differentiation. We propose that TRs cooperate with KLF9 to regulate hepatocyte proliferation and differentiation and early stages of organogenesis and that TRs exert widespread and important influences on ESC biology. STEM CELLS 2015;33:416-428

Thyroid hormone inhibits hepatocellular carcinoma progression via induction of differentiation and metabolic reprogramming

“…1C). Among the T3-activated transcription factors, it was of particular interest to find Klf9, a Kruppel-like factor that contains a thyroid hormone response element and is implicated in the regulation of the balance between pluripotency, self-renewal, differentiation, and metabolism [18][19][20] ( Fig. S4).…”

T3/TRs axis in hepatocellular carcinoma: new concepts for an old pair

“…The potential relevance of T 3 -induced differentiation in modulating tumour development is also highlighted by a work implicating Krüppel-like factors (KLFs) in TR-induced differentiation (Cvoro et al 2015). KLFs are classified as a part of Sp1/KLF family of zinc-fingercontaining transcription factors and play an important role in proliferation, differentiation, apoptosis, inflammation and development (Cao et al 2010).…”

Defined three-dimensional culture conditions mediate efficient induction of definitive endoderm lineage from human umbilical cord Wharton’s jelly mesenchymal stem cells

“…Cvoro et al reported that during DE induction from hESCs and hiPSCs, thyroid hormone suppresses notch-signaling genes through the activation of the Kruppel-like factor KLF-9 [71, 72]. Both exendin-4 and EGF direct the DE differentiation toward primitive gut tube endoderm, and enhance proinsulin biosynthesis and expansion of pancreatic progenitor at later stages of hESC and hiPSC differentiation [18].…”