Engineered liposomes targeting hepatic stellate cells overcome pathological barriers and reverse liver fibrosis

Dual pathological barriers, including capillarized liver sinusoidal endothelial cells (LSECs) and deposited extracellular matrix (ECM), result in insufficient drug delivery, significantly compromising the anti-fibrosis efficacy. Additionally, excessive reactive oxygen species (ROS) in the hepatic microenvironment are crucial factors contributing to the progression of liver fibrosis. Hence, hyaluronic acid (HA) modified liposomes co-delivering all-trans retinoic acid (RA) and L-arginine (L-arg) were constructed to reverse hepatic fibrosis. By exhibiting exceptional responsiveness to the fibrotic microenvironment, our cleverly constructed liposomes efficiently disrupted the hepatic sinus pathological barrier, leading to enhanced accumulation of liposomes in activated hepatic stellate cells (HSCs) and subsequent induction of HSCs quiescence. Specially, excessive ROS in liver fibrosis promotes the conversion of loaded L-arg to nitric oxide (NO). The ensuing NO serves to reestablish the fenestrae structure of capillarized LSECs, thereby augmenting the likelihood of liposomes reaching the hepatic sinus space. Furthermore, subsequent oxidation of NO by ROS into peroxynitrite activates pro-matrix metalloproteinases into matrix metalloproteinases, which further disrupts the deposited ECM barrier. Consequently, this NO-induced cascade process greatly amplifies the accumulation of liposomes within activated HSCs. More importantly, the released RA could induce quiescence of activated HSCs by significantly downregulating the expression of myosin light chain-2, thereby effectively mitigating excessive collagen synthesis and ultimately leading to the reversal of liver fibrosis. Overall, this integrated systemic strategy has taken a significant step forward in advancing the treatment of liver fibrosis.

Restoration of Sinusoid Fenestrae Followed by Targeted Nanoassembly Delivery of an Anti-Fibrotic Agent Improves Treatment Efficacy in Liver Fibrosis

During the onset of liver fibrosis, capillarized liver sinusoidal endothelial cells (LSECs) limit substance exchange between the blood and the Disse space, further accelerating hepatic stellate cell (HSCs) activation and fibrosis progression. Limited accessibility of therapeutics to the Disse space is often overlooked and remains a major bottleneck for HSCs-targeted therapy in liver fibrosis. Here, an integrated systemic strategy for liver fibrosis treatment is reported, utilizing pretreatment with the soluble guanylate cyclase stimulator, riociguat, followed by insulin growth factor 2 receptor-mediated targeted delivery of the anti-fibrosis agent, JQ1, via peptide-nanoparticles (IGNP-JQ1). The riociguat reversed the liver sinusoid capillarization to maintain a relatively normal LSECs porosity, thus facilitating the transport of IGNP-JQ1 through the liver sinusoid endothelium wall and enhancing the accumulation of IGNP-JQ1 in the Disse space. IGNP-JQ1 is then selectively taken up by activated HSCs, inhibiting their proliferation and decreasing collagen deposition in the liver. The combined strategy results in significant fibrosis resolution in carbon tetrachloride-induced fibrotic mice as well as methionine-choline-deficient-diet-induced nonalcoholic steatohepatitis (NASH) mice. The work highlights the key role of LSECs in therapeutics transport through the liver sinusoid. The strategy of restoring LSECs fenestrae by riociguat represents a promising approach for liver fibrosis treatment.