human-dupuytren-s-ex-vivo-culture-for-study-myofibroblasts

Human Dupuytren's <em>Ex Vivo</em> Culture for the Study of Myofibroblasts and Extracellular Matrix Interactions

Organ fibrosis or &#8220;scarring&#8221; is known to account for a high death toll due to the extensive amount of disorders and organs affected (from ...

Leiden University Medical Center

Adult organ regeneration occurs in many systems such as in liver, skin, intestine and heart, indicating that postnatal life is not a static or quiescent state but a dynamic and complex process. The liver is a spectacular organ, exhibiting high regenerative capacity crucial for homeostasis and tissue repair: injuries induced mechanically or chemically, can be completely restored. Regeneration involves extensive cell division, inflammation and extracellular matrix remodeling processes. At the molecular level, one of the key mediators of regeneration response is the secreted cytokine transforming growth factor-β (TGFβ). TGFβ is a profibrogenic and anti-proliferative protein with pleiotropic functions depending on the cellular context. In this review, we discuss the role of TGFβ in the development of the liver and in adult liver regeneration, with particular emphasis on its role in regulation of hepatocyte regeneration and in hepatic progenitor cell-induced regeneration. Finally, we give an overview of the current direction of liver research towards cell replacement therapies.

TGFβ signaling in liver regeneration.

Brown adipose tissue (BAT) dissipates energy stored in triglycerides as heat via the uncoupling protein UCP-1 and is a promising target to combat hyperlipidemia and obesity. BAT is densely innervated by the sympathetic nervous system, which increases BAT differentiation and activity upon cold exposure. Recently, Bone Morphogenetic Protein 7 (BMP7) was identified as an inducer of BAT differentiation. We aimed to elucidate the role of sympathetic activation in the effect of BMP7 on BAT by treating mice with BMP7 at varying ambient temperature, and assessed the therapeutic potential of BMP7 in combating obesity.

BMP7 activates brown adipose tissue and reduces diet-induced obesity only at subthermoneutrality.

Dupuytren's disease (DD) is a benign fibroproliferative disease of the hand. It is characterized by the excessive production of extracellular matrix (ECM) proteins, which form a strong fibrous tissue between the handpalm and fingers, permanently disrupting the fine movement ability. The major contractile element in DD is the myofibroblast (MFB). This cell has both fibroblast and smooth muscle cell-type characteristics and causes pathological collagen deposition. MFBs generate contractile forces that are transmitted to the surrounding collagen matrix. Μajor profibrotic factors are members of the transforming growth factor-β (TGFβ) pathway which directly regulate the expression levels of several fibrous proteins such as collagen type 1, type 3, and α-smooth muscle actin. Molecular modulation of this signaling pathway could serve as a therapeutic approach. We, therefore, have developed an ex vivo "clinical trial" system to study the properties of intact, patient-derived resection specimens. In these culture conditions, Dupuytren's tissue retains its three-dimensional (3D) structure and viability. As a novel antifibrotic therapeutic approach, we targeted TGFβ type 1 receptor (also termed activin receptor-like kinase 5) expression in cultured Dupuytren's specimens by antisense oligonucleotide-mediated exon skipping. Antisense oligonucleotides targeting activin receptor-like kinase 5 showed specific reduction of ECM and potential for clinical application.Molecular Therapy-Nucleic Acids (2014) 3, e142; doi:10.1038/mtna.2013.69; published online 21 January 2014.

Novel Ex Vivo Culture Method for the Study of Dupuytren's Disease: Effects of TGFβ Type 1 Receptor Modulation by Antisense Oligonucleotides.

Liver exhibits a remarkable maintenance of functional homeostasis in the presence of a variety of damaging toxic factors. Tissue regeneration involves cell replenishment and extracellular matrix remodeling. Key regulator of homeostasis is the transforming growth factor-β (TGFβ) cytokine. To understand the role of TGFβ during liver regeneration, we used the single-dose carbon tetrachloride (CCl4) treatment in mice as a model of acute liver damage. We combined this with in vivo inhibition of the TGFβ pathway by a small molecule inhibitor, LY364947, which targets the TGFβ type I receptor kinase [activin receptor-like kinase 5 (ALK5)] in hepatocytes but not in activated stellate cells. Co-administration of LY364947 inhibitor and CCl4 toxic agent resulted in enhanced liver regeneration; cell proliferation (measured by PCNA, phosphorylated histone 3, p21) levels were increased in CCl4 + LY364947 versus CCl4-treated mice. Recovery of CCl4-metabolizing enzyme CYP2E1 expression in hepatocytes is enhanced 7 days after CCl4 intoxication in the mice that received also the TGFβ inhibitor. In summary, a small molecule inhibitor that blocks ALK5 downstream signaling and halts the cytostatic role of TGFβ pathway results in increased cell regeneration and improved liver function during acute liver damage. Thus, in vivo ALK5 modulation offers insight into the role of TGFβ, not only in matrix remodeling and fibrosis, but also in cell regeneration.

Article	Year
TGFβ signaling in liver regeneration. Current pharmaceutical design\| PubMed ID: 22630085	2012
BMP7 activates brown adipose tissue and reduces diet-induced obesity only at subthermoneutrality. PloS one\| PubMed ID: 24066098	2013
Novel Ex Vivo Culture Method for the Study of Dupuytren's Disease: Effects of TGFβ Type 1 Receptor Modulation by Antisense Oligonucleotides. Molecular therapy. Nucleic acids\| PubMed ID: 24448195	2014
Inhibition of TGFβ type I receptor activity facilitates liver regeneration upon acute CCl4 intoxication in mice. Archives of toxicology\| PubMed ID: 25566828	2015

Sofia Karkampouna

Biography

JoVE Journal Publications

Other Publications