Fibroblast activation protein activated antifibrotic peptide delivery attenuates fibrosis in mouse models of liver fibrosis

Aptamer-modified melittin micelles efficiently inhibit osteosarcoma deterioration by inducing immunogenic cell death

Osteosarcoma (OS) is the most common primary bone malignancy characterized by deposition of an immature osteoid matrix. OS treatment has proven challenging because of the high risk of metastatic progression and recurrence after chemotherapy. Melittin (MLT) is recognized as a potential antitumor candidate to overcome chemotherapy resistance and provoke superior immunostimulatory effects. However, the application of MLT to OS is hampered by severe toxic side effects and a lack of tumor-targeting ability. Herein, a self-assembled nanopolymer named LC09-MLT@F127 was developed by binding MLT with F127 micelles and then modifying an aptamer (LC09) for targeted drug delivery during OS treatment. LC09-MLT@F127 exhibited significant OS-targeting ability in vitro and in vivo owing to the aptamer LC09 decoration. Moreover, LC09-MLT@F127 significantly reduced the hemolytic toxicity of MLT while maintaining its tumor-killing ability. In an orthotopic transplantation model of OS, LC09-MLT@F127 induced immunogenic cell death and facilitated the maturation of dendritic cells (DCs), thereby resulting in the activation of tumor-specific immune responses and the inhibition of OS deterioration. Taken together, these finding suggest that LC09-MLT@F127 may be an encouraging MLT-based immunotherapy option for OS.

Biomimetic nanoparticles for targeted therapy of liver disease

Liver fibrosis is a progressive and fatal condition characterized by stiffness and scarring of the liver due to excessive buildup of extracellular matrix (ECM) proteins. If left untreated, it can progress to liver cirrhosis and hepatocellular carcinoma (HCC)-one of the fastest-rising causes of cancer mortality in the United States. Despite the increased prevalence of liver fibrosis due to infections, exposure to toxins, and unhealthy lifestyles, there are no effective treatments available. Recent advances in nanomedicine can lead to more targeted and effective strategies for treating liver diseases than existing treatments. In particular, the use of biomimetic nanoparticles (NPs) such as liposomes and cell-membrane-coated NPs is of interest. NPs functionalized with cell membranes mimic the properties of the source cell used and provide inherent immune evasion ability, homologous adhesion, and prolonged circulation. This review explores the types of biomimetic coatings, different cargoes delivered through biomimetic NPs for various treatment modalities, and the type of core NPs used for targeting liver fibrosis and HCC.

Legumain In Situ Engineering Promotes Efferocytosis of CAR Macrophage to Treat Cardiac Fibrosis

Uncontrolled and excessive cardiac fibrosis after myocardial infarction (MI) is a primary contributor to mortality by heart failure. Chimeric antigen receptor macrophage (CAR-MΦ) therapy shows great promise in cardiac fibrosis, however, the overwhelming apoptotic cells after MI results in an overburdened efferocytosis in CAR-MΦ, which compromises their antifibrotic potency. This work here reports an in situ engineered legumain (Lgmn) to elevate the cargo degradation of phagolysosome for promoting the efferocytosis of CAR-MΦs, restoring their antifibrotic capability. Specifically, with the in-house customized macrophages-targeting lipid nanoparticles, this work first creates an efferocytosis-boosted fibrosis-specific CAR-MΦs by introducing dual mRNAs that encode Lgmn, an endolysosomal cysteine protease, along with an anti-fibroblast activation protein (FAP) CAR, respectively. This data demonstrate these CAR-MΦs displayed a significantly increased phagocytic capacity as well as improved efferocytosis and enhanced antifibrotic capability. Treatment with the in situ reprogrammed CAR-MΦs in MI mice obviously reduced the infarct size and mitigated cardiac fibrosis, leading to significant restoration of cardiac function. In sum, these findings establish that promoting efferocytosis through Lgmn engineering effectively relieved the overburdened efferocytosis of CAR-MΦs, and enhanced their treatment efficacy of cardiac fibrosis with broad application in other fibrotic diseases.

Cutting-edge biotherapeutics and advanced delivery strategies for the treatment of metabolic dysfunction-associated steatotic liver disease spectrum

Metabolic dysfunction-associated steatotic liver disease (MASLD), a condition with the potential to progress into liver cirrhosis or hepatocellular carcinoma, has become a significant global health concern due to its increasing prevalence alongside obesity and metabolic syndrome. Despite the promise of existing therapies such as thyroid hormone receptor-β (THR-β) agonists, PPAR agonists, FXR agonists, and GLP-1 receptor agonists, their effectiveness is limited by the complexity of the metabolic, inflammatory, and fibrotic pathways that drive MASLD progression, encompassing steatosis, metabolic dysfunction-associated steatohepatitis (MASH), and reversible liver fibrosis. Recent advances in targeted therapeutics, including RNA interference (RNAi), mRNA-based gene therapies, monoclonal antibodies, proteolysis-targeting chimeras (PROTAC), peptide-based strategies, cell-based therapies such as CAR-modified immune cells and stem cells, and extracellular vesicle-based approaches, have emerged as promising interventions. Alongside these developments, innovative drug delivery systems are being actively researched to enhance the stability, precision, and therapeutic efficacy of these biotherapeutics. These delivery strategies aim to optimize biodistribution, improve target-specific action, and reduce systemic exposure, thus addressing critical limitations of existing treatment modalities. This review provides a comprehensive exploration of the underlying biological mechanisms of MASLD and evaluates the potential of these cutting-edge biotherapeutics in synergy with advanced delivery approaches to address unmet clinical needs. By integrating fundamental disease biology with translational advancements, it aims to highlight future directions for the development of effective, targeted treatments for MASLD and its associated complications.

Cancer-associated fibroblasts in hepatocellular carcinoma: heterogeneity, mechanisms and therapeutic targets

Hepatocellular carcinoma (HCC) is one of the common malignant cancers worldwide. Although immunotherapy has improved the treatment outcome in HCC, a significant percentage of patients with advanced HCC still cannot benefit from immunotherapy. Therefore, developing new targets or combination therapeutic strategies to improve the efficacy of immunotherapy is urgently needed. A deeper understanding of the mechanisms underlying immune regulation may help in this regard. The tumor microenvironment (TME) consists of a diverse set of components modulating the efficacy of immunotherapy. Cancer-associated fibroblasts (CAFs) are critical components of the TME and can regulate both tumor and immune cells through secreted cytokines and exosomes that impact various signaling pathways in target cells. CAF-derived cytokines can also participate in extracellular matrix (ECM) remodeling, thereby impacting cancer progression and tumor responsiveness to immunotherapy among other effects. A thorough understanding of the phenotypic and functional profile dynamism of CAFs may lead the way for new treatment strategies and/or better treatment outcomes in HCC patients. In this review, we outline the biomarkers and functional heterogeneity of CAFs in HCC and elaborate on molecular mechanisms of CAFs, including anti-programmed cell death protein 1 (PD-1)/PD-ligand 1 (PD-L1) immunotherapy. We also examine current clinical implications of CAFs-related targets as potential therapeutic candidates in HCC.

Targeting Hepatic Stellate Cells for the Prevention and Treatment of Liver Cirrhosis and Hepatocellular Carcinoma: Strategies and Clinical Translation

Hepatic stellate cells (HSC) are the major source of myofibroblasts (MFB) in fibrosis and cancer- associated fibroblasts (CAF) in both primary and metastatic liver cancer. Over the past few decades, there has been significant progress in understanding the cellular and molecular mechanisms by which liver fibrosis and HCC occur, as well as the key roles of HSC in their pathogenesis. HSC-targeted approaches using specific surface markers and receptors may enable the selective delivery of drugs, oligonucleotides, and therapeutic peptides that exert optimized anti-fibrotic and anti-HCC effects. Recent advances in omics, particularly single-cell sequencing and spatial transcriptomics, hold promise for identifying new HSC targets for diagnosing and treating liver fibrosis/cirrhosis and liver cancer.

Synthesis and application of astaxanthin-loaded procyanidins/sea cucumber peptide nanoparticles with good antioxidant and pH-responsive capacities

Astaxanthin (AXT), a keto-carotenoid with potent antioxidant properties, has the ability to reduce lipid peroxidation and effectively inhibit lipid peroxidation caused by free radicals. Given the oxidative susceptibility of AXT during processing, storage, and digestion, along with the effectiveness of novel food-grade drug delivery systems, we engineered an AXT-loaded procyanidins (PCs) and sea cucumber peptide (SCP) nanoparticles (AXT@NPs) to enhance its bioavailability. The research results indicatedthat spherical AXT@NPs, approximately 686 nm in size, had a higher drug-loading capacity and an intelligent pH-response performance. Additionally, this carrier demonstrated excellent stability against temperature and ultra-violet radiation, as well as DPPH and ABTS free radical scavenging properties. In vitro cell experiments revealed that AXT@NPs significantly inhibited the production of reactive oxygen species (ROS) and the reduction of mitochondrial membrane potential caused by H2O2. The oxidative stress plays a pivotal role in the formation of liver fibrosis. In vivo liver fibrosis studies in mice confirmed that AXT@NPs could effectively alleviate damaged liver tissues, decreasing collagen deposition, and reducing oxidative damage by extending the action time of AXT in liver tissue. These findings indicate that AXT@NPs offer a novel nutritional intervention strategy for antifibrosis therapy by significantly enhancing bioavailability and effectively reducing oxidative stress.

Glycyrrhizinate Monoammonium Cysteine-Loaded Lipid Nanoparticles Allow for Improved Acute Liver Injury Therapy

Background: Acute liver injury (ALI) is a prevalent and potentially lethal condition globally, where pharmacotherapy plays a vital role. However, challenges such as rapid drug excretion and insufficient concentration at hepatic lesions often impede the treatment's effectiveness. Methods: We successfully prepared glycyrrhizinate monoammonium cysteine (GMC)-loaded lipid nanoparticles (LNPs) using high-pressure homogenization. The characterization and safety of the LNPs were measured using electrophoretic light scattering (ELS), transmission electron microscopy (TEM), dynamic light scattering (DLS), cytotoxicity assays, and hemolysis tests. The distribution of LNPs in mice was explored using fluorescence labeling methods. The encapsulation efficiency of LNP-GMC was detected using High-Performance Liquid Chromatography (HPLC), and its slow-release effect on GMC was assessed through dialysis. The therapeutic effects of LNP-GMC and pure GMC on the ALI model were evaluated using fibroblast activation protein inhibitor (FAPI) PET imaging, blood biochemical indicators, and liver pathology slices. Results: The encapsulation of GMC in LNPs enhances drug stability and prolongs its hepatic retention, significantly improving its bioavailability and sustained release within the liver. This study also explores the expression of fibroblast activation protein (FAP) in ALI, employing 68Ga-FAPI PET/CT imaging for effective differentiation and assessment of liver injury. Conclusions: Our results suggest that LNPs offer an enhanced therapeutic approach for ALI treatment, reducing the required drug dosage, and 68Ga-FAPI PET/CT imaging provides a novel method for diagnosis and treatment assessment. This study contributes valuable insights into the utilization of LNPs in liver disease treatment, presenting a promising direction for future clinical applications.

A Vaccine Against Fibroblast Activation Protein Improves Murine Cardiac Fibrosis by Preventing the Accumulation of Myofibroblasts

BACKGROUND

Myofibroblasts are primary cells involved in chronic response-induced cardiac fibrosis. Fibroblast activation protein (FAP) is a relatively specific marker of activated myofibroblasts and a potential target molecule. This study aimed to clarify whether a vaccine targeting FAP could eliminate myofibroblasts in chronic cardiac stress model mice and reduce cardiac fibrosis.

METHODS

We coadministered a FAP peptide vaccine with a cytosine-phosphate-guanine (CpG) K3 oligonucleotide adjuvant to male C57/BL6J mice and confirmed an elevation in the anti-FAP antibody titer. After continuous angiotensin II and phenylephrine administration for 28 days, we evaluated the degree of cardiac fibrosis and the number of myofibroblasts in cardiac tissues.

RESULTS

We found that cardiac fibrosis was significantly decreased in the FAP-vaccinated mice compared with the angiotensin II and phenylephrine control mice (3.45±1.11% versus 8.62±4.79%; P=4.59×10-3) and that the accumulation of FAP-positive cells was also significantly decreased, as indicated by FAP immunohistochemical staining (4077±1746 versus 7327±1741 cells/mm2; FAP vaccine versus angiotensin II and phenylephrine control; P=6.67×10-3). No systemic or organ-specific inflammation due to antibody-dependent cell cytotoxicity induced by the FAP vaccine was observed. Although the transient activation of myofibroblasts has an important role in maintaining the structural robustness in the process of tissue repair, the FAP vaccine showed no adverse effects in myocardial infarction and skin injury models.

CONCLUSIONS

Our study demonstrates the FAP vaccine can be a therapeutic tool for cardiac fibrosis.

Pathological Microenvironment-Remodeling Nanoparticles to Alleviate Liver Fibrosis: Reversing Hepatocytes-Hepatic Stellate Cells Malignant Crosstalk

During the onset and malignant development of liver fibrosis, the pernicious interplay between damaged hepatocytes and activated hepatic stellate cells (HSCs) induce a self-perpetuating vicious cycle, deteriorating fibrosis progression and posing a grave threat to public health. The secretions released by damaged hepatocytes and activated HSCs interact through autocrine or paracrine mechanisms, involving multiple signaling pathways. This interaction creates a harsh microenvironment and weakens the therapeutic efficacy of single-cell-centric drugs. Herein, a malignant crosstalk-blocking strategy is prompted to remodel vicious cellular interplay and reverse pathological microenvironment to put an end to liver fibrosis. Collagenases modified, bardoxolone and siTGF-β co-delivered nanoparticles (C-NPs/BT) are designed to penetrate the deposited collagen barriers and further regulate the cellular interactions through upregulating anti-oxidative stress capacity and eliminating the pro-fibrogenic effects of TGF-β. The C-NPs/BT shows successful remodeling of vicious cellular crosstalk and significant disease regression in animal models. This study presents an innovative strategy to modulate cellular interactions for enhanced anti-fibrotic therapy and suggests a promising approach for treating other chronic liver diseases.

TWISTed fibroblasts: New drivers of intestinal fibrosis in Crohn's disease

Fibrosis is the pathological consequence of chronic inflammation. In Crohn's disease (CD), fibrostenotic complications occur with 50-70 % frequency as a failure to properly repair the tissue damage. Intestinal stenosis requires surgical intervention and relapses in most patients. Mesenchymal cells encompassed of heterogeneous cell subsets orchestrate this complex process. The lack of a full characterization of the stromal diversity and function in CD has consequently slowed the development of anti-fibrotic targets. Two recent studies align together demonstrating FAP+TWIST1+ fibroblasts as the primary mesenchymal population driving intestinal fibrosis in CD. Genetic and pharmacological targeting of Twist1 in mouse models proved the functional role of Fap+Twist1+ fibroblasts and indicate the use of the Twist1 inhibitor harmine as a potential therapeutic strategy to revert fibrosis.

Precisely Controlling the Activation of an Iron-Locked Drug Generator in the Liver Sinusoid to Enhance Barrier Penetration and Reduction of Liver Fibrosis

Complex physical barriers and the nanomaterial's clearance mechanism in the liver greatly hinder the feasibility of using a conventional liver-targeting nanoplatform to deliver antifibrotic drugs to pathological sites for the treatment of liver fibrosis. Here, a novel drug delivery strategy was designed to overcome drug penetration barriers in a fibrotic liver and cooperated with oral nattokinase (NKase)-mediated antifibrosis therapy as a proof of concept, which relies on the coadministration of a nanosized iron-locked drug generator (named Pro-HAase) and orally absorbed iron chelator deferasirox (DFX). Such a strategy starts from the rapid accumulation of intravenously injected Pro-HAase in the microcapillaries of the fibrotic liver followed by disrupting the polyphenol-iron coordination inside Pro-HAase by DFX, liberating antifibrotic components, including procyanidine (PA) and hyaluronidase (HAase). Attractively, absorption of DFX requires the sequential processes of traversing the intestinal mucosa and targeting the liver, which enable DFX to preferentially disassemble Pro-HAase accumulated in the liver sinusoid rather than in systemic circulation or other organs, thus avoiding the off-target activation of Pro-HAase and depletion of the normal iron pool. The in situ disassembly process decreases the sequestration of Pro-HAase by cells of the mononuclear phagocyte system and promotes gradient-driven permeation of therapeutic components to surrounding liver tissues within 2 h, accompanied by biliary excretion of the inactive iron-DFX complex. As a result, the cooperation of Pro-HAase and DFX not only allows NKase-mediated therapy to completely reverse liver fibrosis but also suppresses the chronic hepatotoxicity of residual liver iron after multiple doses of Pro-HAase. The high spatiotemporal precision, unique barrier-penetration mechanism, and self-detoxification ability of this strategy will inspire the rational design of analogous iron-locked nanosystems to improve the therapeutic outcomes of liver fibrosis or other liver diseases.

Targeting fibroblast activation protein with chimeric antigen receptor macrophages

Under the rapid advancement of chimeric antigen receptor T cell (CAR-T) technology, CAR-macrophages (CAR-Ms) are also being developed currently in the pre-clinical stage and have been shown to inhibit tumor growth in several mouse tumor models. Fibroblast activation protein (FAP) is a type II transmembrane serine protease, which is expressed in stromal fibroblasts of over 90 % of common human epithelial cancers and is upregulated in fibrotic diseases of the liver, lung and colon, etc. In this study, we firstly constructed FAP-CAR macrophages to target FAP+ cells through in vitro phagocytosis assays. In subsequent in vivo assays, we discovered that FAP-CAR-ΔZETA bone marrow-derived macrophages (BMDMs) rather than FAP-CAR BMDMs, exhibited a pronounced anti-tumor effect in mouse subcutaneous MC38 colon cancer model. In addition, FAP-CAR and FAP-CAR-ΔZETA BMDMs therapy could effectively improve CCl4-induced liver fibrosis in mice. Collectively, CAR-Ms targeting FAP demonstrated great therapeutic potential in cancer and liver fibrosis therapy.

Nano-encapsulation of drugs to target hepatic stellate cells: Toward precision treatments of liver fibrosis

Liver fibrosis is characterized by excessive extracellular matrix (ECM) deposition triggered by hepatic stellate cells (HSCs). As central players in fibrosis progression, HSCs are the most important therapeutic targets for antifibrotic therapy. However, owing to the limitations of systemic drug administration, there is still no suitable and effective clinical treatment. In recent years, nanosystems have demonstrated expansive therapeutic potential and evolved into a clinical modality. In liver fibrosis, nanosystems have undergone a paradigm shift from targeting the whole liver to locally targeted modifying processes. Nanomedicine delivered to HSCs has significant potential in managing liver fibrosis, where optimal management would benefit from targeted delivery, personalized therapy based on the specific site of interest, and minor side effects. In this review, we present a brief overview of the role of HSCs in the pathogenesis of liver fibrosis, summarize the different types of nanocarriers and their specific delivery applications in liver fibrosis, and highlight the biological barriers associated with the use of nanosystems to target HSCs and approaches available to solve this issue. We further discuss in-depth all the molecular target receptors overexpressed during HSC activation in liver fibrosis and their corresponding ligands that have been used for drug or gene delivery targeting HSCs.

Non-invasive visualization of liver fibrosis with [68Ga]Ga-DOTA-FAPI-04 PET from preclinical insights to clinical translation

PURPOSE

The reversibility of early liver fibrosis highlights the need for improved early detection and monitoring techniques. Fibroblast activation protein (FAP) is a promising theranostics target significantly upregulated during fibrosis. This preclinical and preliminary clinical study investigated a FAP-targeted probe, gallium-68-labeled FAP inhibitor 04 ([68Ga]Ga-DOTA-FAPI-04), for its capability to visualize liver fibrosis.

METHODS

The preclinical study employed [68Ga]Ga-DOTA-FAPI-04 micro-positron emission tomography (PET)/computed tomography (CT) on carbon tetrachloride-induced mice model (n = 34) and olive oil-treated control group (n = 26), followed by validation of the probe's biodistribution. Hepatic uptake was correlated with fibrosis and inflammation levels, quantified through histology and serum assays. FAP and α-smooth muscle actin expression were determined by immunohistochemistry, as well as immunofluorescence. The subsequent clinical trial enrolled 26 patients with suspected or confirmed liver fibrosis to undergo [68Ga]Ga-DOTA-FAPI-04 PET/magnetic resonance imaging or PET/CT. Key endpoints included correlating [68Ga]Ga-DOTA-FAPI-04 uptake with histological inflammation grades and fibrosis stages, and evaluating its diagnostic and differential efficacy compared to established serum markers and liver stiffness measurement (LSM).

RESULTS

[68Ga]Ga-DOTA-FAPI-04 mean uptake in mice livers was notably higher than in control mice, increasing from week 6 [0.70 ± 0.11 percentage injected dose per cubic centimeter (%ID/cc)], peaking at week 10 (0.97 ± 0.15%ID/cc) and slightly reducing at week 12 (0.89 ± 0.28%ID/cc). The hepatic biodistribution and FAP expression showed a consistent trend. In the patient cohort, hepatic [68Ga]Ga-DOTA-FAPI-04 uptake presented moderate correlations with inflammation grades (r = 0.517 to 0.584, all P < 0.05) and fibrosis stages (r = 0.653 to 0.698, all P < 0.01). The average SUVmax to background ratio in the liver showed superior discriminative ability, especially between stage 0 and stage 1, outperforming LSM (area under curve 0.984 vs. 0.865).

CONCLUSION

[68Ga]Ga-DOTA-FAPI-04 PET shows significant potential for non-invasive visualization and dynamic monitoring of liver fibrosis in both preclinical experiment and preliminary clinical trial, especially outperforming other common clinical indicators in the early stage.

TRIAL REGISTRATION

NCT04605939. Registered October 25, 2020, https://clinicaltrials.gov/study/NCT04605939.

A self-immobilizing near-infrared fluorogenic probe for in vivo imaging of fibroblast activation protein-α

Fibroblast activation protein-α (FAP) plays a crucial role in various physiological and pathological processes, making it a key target for cancer diagnostics and therapeutics. However, in vivo detection of FAP activity with fluorogenic probes remains challenging due to the rapid diffusion and clearance of fluorescent products from the target. Herein, we developed a self-immobilizing near-infrared (NIR) fluorogenic probe, Hcy-CF2H-PG, by introducing a difluoromethyl group to FAP substrate-caged NIR fluorophore. Upon selective activation by FAP, the fluorescence of Hcy-CF2H-PG was triggered, followed by the covalent labelling of FAP. Hcy-CF2H-PG demonstrated significantly improved sensitivity, selectivity, and long-lasting labelling capacity for FAP both in vitro and in vivo, compared to that of non-immobilized probes. This represents a noteworthy advancement in FAP detection and cancer diagnostics within complex physiological systems.

RNA nanotherapeutics with fibrosis overexpression and retention for MASH treatment

Metabolic dysfunction-associated steatohepatitis (MASH) poses challenges for targeted delivery and retention of therapeutic proteins due to excess extracellular matrix (ECM). Here we present a new approach to treat MASH, termed "Fibrosis overexpression and retention (FORT)". In this strategy, we design (1) retinoid-derivative lipid nanoparticle (LNP) to enable enhanced mRNA overexpression in fibrotic regions, and (2) mRNA modifications which facilitate anchoring of therapeutic proteins in ECM. LNPs containing carboxyl-retinoids, rather than alcohol- or ester-retinoids, effectively deliver mRNA with over 10-fold enhancement of protein expression in fibrotic livers. The carboxyl-retinoid rearrangement on the LNP surface improves protein binding and membrane fusion. Therapeutic proteins are then engineered with an endogenous collagen-binding domain. These fusion proteins exhibit increased retention in fibrotic lesions and reduced systemic toxicity. In vivo, fibrosis-targeting LNPs encoding fusion proteins demonstrate superior therapeutic efficacy in three clinically relevant male-animal MASH models. This approach holds promise in fibrotic diseases unsuited for protein injection.

Delivery Strategy to Enhance the Therapeutic Efficacy of Liver Fibrosis via Nanoparticle Drug Delivery Systems

Liver fibrosis (LF) is a pathological repair reaction caused by a chronic liver injury that affects the health of millions of people worldwide, progressing to life-threatening cirrhosis and liver cancer without timely intervention. Due to the complexity of LF pathology, multiple etiological characteristics, and the deposited extracellular matrix, traditional drugs cannot reach appropriate targets in a time-space matching way, thus decreasing the therapeutic effect. Nanoparticle drug delivery systems (NDDS) enable multidrug co-therapy and develop multifactor delivery strategies targeting pathological processes, showing great potential in LF therapy. Based on the pathogenesis and the current clinical treatment status of LF, we systematically elucidate the targeting mechanism of NDDS used in the treatment of LF. Subsequently, we focus on the progress of drug delivery applications for LF, including combined delivery for the liver fibrotic pathological environment, overcoming biological barriers, precise intracellular regulation, and intelligent responsive delivery for the liver fibrotic microenvironment. We hope that this review will inspire the rational design of NDDS for LF in the future in order to provide ideas and methods for promoting LF regression and cure.

Boiling histotripsy exhibits anti-fibrotic effects in animal models of liver fibrosis

Liver fibrosis is a hallmark of chronic liver disease which could lead to liver cirrhosis or liver cancer. However, there is currently lack of a direct treatment for liver fibrosis. Boiling histotripsy (BH) is an emerging non-invasive high-intensity focused ultrasound technique that can be employed to mechanically destruct solid tumour at the focus via acoustic cavitation without significant adverse effect on surrounding tissue. Here, we investigated whether BH can mechanically fractionate liver fibrotic tissue thereby exhibiting an anti-fibrotic effect in an animal model of liver fibrosis. BH-treated penumbra and its identical lobe showed reduced liver fibrosis, accompanied by increased hepatocyte specific marker expression, compared to the BH-untreated lobe. Furthermore, BH treatment improved serological liver function markers without notable adverse effects. The ability of BH to reduce fibrosis and promote liver regeneration in liver fibrotic tissue suggests that BH could potentially be an effective and reliable therapeutic approach against liver fibrosis.

Tumor microenvironment reprogramming combined with immunogenic enhancement by nanoemulsions potentiates immunotherapy

The combination of immune checkpoint inhibitors and immunogenic cell death (ICD) inducers has become a promising strategy for the treatment of various cancers. However, its efficacy remains unmet because of the dense stroma and defective vasculatures in the tumor microenvironment (TME) that restricts the intratumoral infiltration of cytotoxic T lymphocytes (CTLs). Herein, cancer-associated fibroblasts (CAFs)-targeted nanoemulsions are tailored to combine the ICD induction and the TME reprogramming to sensitize checkpoint blockade immunotherapy. Melittin, as an ICD inducer and an antifibrotic agent, is efficiently encapsulated into the nanoemulsion accompanied by a nitric oxide donor to improve its bioavailability and tumor targeting. The nanoemulsions exhibited dual functionality by directly inducing direct cancer cell death and enhancing the tumoral immunogenicity, while also synergistically reprogramming the TME through reversing the activated CAFs, decreasing collagen deposition and restoring tumor vessels. Consequently, these nanemulsions successfully facilitated the CTLs infiltration and suppressing the recruitment of immunosuppressive cells. A combination of AE-MGNPs and anti-CTLA-4 antibody greatly elicited a striking level of antitumor T-cell response to suppress tumor growth in CAFs-rich colorectal tumor models. Our work emphasized the integration of the ICD induction with simultaneous modulation of the TME to enhance the sensitivity of patients to checkpoint blockade immunotherapy.

Nanomodulator-Mediated Restructuring of Adipose Tissue Immune Microenvironments for Antiobesity Treatment

In obesity, the interactions between proinflammatory macrophages and adipocytes in white adipose tissues are known to play a crucial role in disease progression by providing inflammatory microenvironments. Here, we report that the functional nanoparticle-mediated modulation of crosstalk between adipocytes and macrophages can remodel adipocyte immune microenvironments. As a functional nanomodulator, we designed antivascular cell adhesion molecule (VCAM)-1 antibody-conjugated and amlexanox-loaded polydopamine nanoparticles (VAPN). Amlexanox was used as a model drug to increase energy expenditure. Compared to nanoparticles lacking antibody modification or amlexanox, VAPN showed significantly greater binding to VCAM-1-expressing adipocytes and lowered the interaction of adipocytes with macrophages. In high fat diet-fed mice, repeated subcutaneous administration of VAPN increased the populations of beige adipocytes and ameliorated inflammation in white adipose tissues. Moreover, the localized application of VAPN in vivo exerted a systemic metabolic effect and reduced metabolic disorders, including insulin tolerance and liver steatosis. These findings suggested that VAPN had potential to modulate the immune microenvironments of adipose tissues for the immunologic treatment of obesity. Although we used amlexanox as a model drug and anti-VCAM-1 antibody in VAPN, the concept of immune nanomodulators can be widely applied to the immunological treatment of obesity.

Vicious Cycle-Breaking Lipid Nanoparticles Remodeling Multicellular Crosstalk to Reverse Liver Fibrosis

During liver fibrogenesis, the reciprocal crosstalk among capillarized liver sinusoidal endothelial cells (LSECs), activated hepatic stellate cells (HSCs), and dysfunctional hepatocytes constructs a self-amplifying vicious cycle, greatly exacerbating the disease condition and weakening therapeutic effect. Limited by the malignant cellular interactions, the previous single-cell centric treatment approaches show unsatisfactory efficacy and fail to meet clinical demand. Herein, a vicious cycle-breaking strategy is proposed to target and repair pathological cells separately to terminate the malignant progression of liver fibrosis. Chondroitin sulfate-modified and vismodegib-loaded nanoparticles (CS-NPs/VDG) are designed to efficiently normalize the fenestrae phenotype of LSECs and restore HSCs to quiescent state by inhibiting Hedgehog signaling pathway. In addition, glycyrrhetinic acid-modified and silybin-loaded nanoparticles (GA-NPs/SIB) are prepared to restore hepatocytes function by relieving oxidative stress. The results show successful interruption of vicious cycle as well as distinct fibrosis resolution in two animal models through multiregulation of the pathological cells. This work not only highlights the significance of modulating cellular crosstalk but also provides a promising avenue for developing antifibrotic regimens.

Comparative Proteomics Inspired Self-Stimulated Release Hydrogel Reinforces the Therapeutic Effects of MSC-EVs on Alzheimer's Disease

The clinical application of extracellular vesicles (EVs)-based therapeutics continues to be challenging due to their rapid clearance, restricted retention, and low yields. Although hydrogel possesses the ability to impede physiological clearance and increase regional retention, it typically fails to effectively release the incorporated EVs, resulting in reduced accessibility and bioavailability. Here an intelligent hydrogel in which the release of EVs is regulated by the proteins on the EVs membrane is proposed. By utilizing the EVs membrane enzyme to facilitate hydrogel degradation, sustained retention and self-stimulated EVs release can be achieved at the administration site. To achieve this goal, the membrane proteins with matrix degrading activity in the mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are identified using comparative proteomics. After that, a hydrogel comprised of self-assembled peptides that are susceptible to degradation by the membrane enzymes present in MSC-EVs is designed and synthesized. After intranasal administration, this peptide hydrogel facilitates sustained and thermo-sensitive release of MSC-EVs, thereby extending the retention of the MSC-EVs and substantially enhancing their potential for treating Alzheimer's disease. This research presents a comparative proteomics-driven approach to intelligent hydrogel design, which holds the capacity to significantly enhance the applicability of EVs in clinical settings.

A network pharmacology approach to explore the molecular mechanism of active peptide ingredients of Carapax Trionycis on liver fibrosis

Carapax Trionycis is a traditional Chinese medicine and it has been clear that oligo‐peptides from Carapax Trionycis extract (CTP) are the main active substances for the treatment of liver diseases. However, little is known about the mechanism of CTP against liver fibrosis. Here, network pharmacology combined with molecular docking were performed to identify the in‐silico molecular mechanism and the potential targets for CTP to ameliorate liver fibrosis. We collected eight active peptides ingredients that published in public databases and predicted the targets. Liver fibrosis related genes were acquired from the GeneCards and DisGeNET platform. Then, we identified a total of 52 peptides‐liver fibrosis‐related genes. KEGG and GO enrichment analyses indicated that these targets are significantly enriched in relaxin signaling pathway, IL‐17 signaling pathway, TNF signaling pathway. We identified the top 10 genes with high centrality measures from the network by CytoHubba, including CASP3, AKT1, IL1B, MMP9, and PTGS2. The molecular docking between these hub genes and the corresponding CTP was performed in GRAMM and visualized by PyMOL. Our results provide an important reference and scientific basis for treating liver fibrosis with CTP.

CAR-T cell therapeutic avenue for fighting cardiac fibrosis: Roadblocks and perspectives

Heart diseases remain the primary cause of human mortality in the world. Although conventional therapeutic opportunities fail to halt or recover cardiac fibrosis, the promising clinical results and therapeutic efficacy of engineered chimeric antigen receptor (CAR) T cell therapy show several advancements. However, the current models of CAR-T cells need further improvement since the T cells are associated with the triggering of excessive inflammatory cytokines that directly affect cardiac functions. Thus, the current study highlights the critical function of heart immune cells in tissue fibrosis and repair. The study also confirms CAR-T cell as an emerging therapeutic for treating cardiac fibrosis, explores the current roadblocks to CAR-T cell therapy, and considers future outlooks for research development.

Fibroblast Activation Protein Alpha (FAPα) in Fibrosis: Beyond a Perspective Marker for Activated Stromal Cells?

The development of tissue fibrosis is a complex process involving the interaction of multiple cell types, which makes the search for antifibrotic agents rather challenging. So far, myofibroblasts have been considered the key cell type that mediated the development of fibrosis and thus was the main target for therapy. However, current strategies aimed at inhibiting myofibroblast function or eliminating them fail to demonstrate sufficient effectiveness in clinical practice. Therefore, today, there is an unmet need to search for more reliable cellular targets to contribute to fibrosis resolution or the inhibition of its progression. Activated stromal cells, capable of active proliferation and invasive growth into healthy tissue, appear to be such a target population due to their more accessible localization in the tissue and their high susceptibility to various regulatory signals. This subpopulation is marked by fibroblast activation protein alpha (FAPα). For a long time, FAPα was considered exclusively a marker of cancer-associated fibroblasts. However, accumulating data are emerging on the diverse functions of FAPα, which suggests that this protein is not only a marker but also plays an important role in fibrosis development and progression. This review aims to summarize the current data on the expression, regulation, and function of FAPα regarding fibrosis development and identify promising advances in the area.

Found in translation-Fibrosis in metabolic dysfunction-associated steatohepatitis (MASH)

Metabolic dysfunction-associated steatohepatitis (MASH) is a severe form of liver disease that poses a global health threat because of its potential to progress to advanced fibrosis, leading to cirrhosis and liver cancer. Recent advances in single-cell methodologies, refined disease models, and genetic and epigenetic insights have provided a nuanced understanding of MASH fibrogenesis, with substantial cellular heterogeneity in MASH livers providing potentially targetable cell-cell interactions and behavior. Unlike fibrogenesis, mechanisms underlying fibrosis regression in MASH are still inadequately understood, although antifibrotic targets have been recently identified. A refined antifibrotic treatment framework could lead to noninvasive assessment and targeted therapies that preserve hepatocellular function and restore the liver's architectural integrity.

Friend or foe? The elusive role of hepatic stellate cells in liver cancer

Liver fibrosis is a substantial risk factor for the development and progression of liver cancer, which includes hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). Studies utilizing cell fate mapping and single-cell transcriptomics techniques have identified quiescent perisinusoidal hepatic stellate cells (HSCs) as the primary source of activated collagen-producing HSCs and liver cancer-associated fibroblasts (CAFs) in HCC and liver metastasis, complemented in iCCA by contributions from portal fibroblasts. At the same time, integrative computational analysis of single-cell, single-nucleus and spatial RNA sequencing data have revealed marked heterogeneity among HSCs and CAFs, with distinct subpopulations displaying unique gene expression signatures and functions. Some of these subpopulations have divergent roles in promoting or inhibiting liver fibrogenesis and carcinogenesis. In this Review, we discuss the dual roles of HSC subpopulations in liver fibrogenesis and their contribution to liver cancer promotion, progression and metastasis. We review the transcriptomic and functional similarities between HSC and CAF subpopulations, highlighting the pathways that either promote or prevent fibrosis and cancer, and the immunological landscape from which these pathways emerge. Insights from ongoing studies will yield novel strategies for developing biomarkers, assessing prognosis and generating new therapies for both HCC and iCCA prevention and treatment.

Selective inhibition of glycolysis in hepatic stellate cells and suppression of liver fibrogenesis with vitamin A-derivative decorated camptothecin micelles

The persistent transformation of quiescent hepatic stellate cells (HSCs) into myofibroblasts (MFs) and the excessive proliferation of MF-HSCs in the liver contribute to the pathogenesis of liver fibrosis, cirrhosis, and liver cancer. Glycolysis inhibition of MF-HSCs can reverse their MF phenotype and suppress their abnormal expansion. Here, we have developed vitamin A-derivative (VA) decorated PEG-PCL polymeric micelles to encapsulate the labile and hydrophobic camptothecin (CPT) and direct its active attack on HSCs, selectively inhibiting of HIF-1α and cellular glycolysis, ultimately repressing hepatic fibrogenesis. The obtained micelles exhibited a good stability, biocompatibility, pH sensitivity, and exceptional HSC-targetability, allowing an efficient accumulation of their carried CPT in acutely and chronically injured livers. On their intracellular release of CPT specifically in MF-HSCs, these CPT micelles nicely inhibited the HIF-1α and a series of glycolytic players in MF-HSCs and prominently suppressed their proliferation and MF phenotypic characteristics. Accordingly, on in vitro administration to the mice challenged by CCl4 or subjected to bile duct ligation, these VA-decorated CPT micelles ameliorated the pathological symptoms of the livers, as evidenced by the significant reduction in serum levels of ALT and AST, infiltration of inflammatory cells, and collagen accumulation, the drastic down-regulation of multiple fibrotic genes, and the good recovery of attenuated hepatocyte CYP2E1 and lipogenesis regulator PPARγ. Overall, the CPT carried by VA-decorated PEG-PCL polymeric micelles can selectively inhibit the glycolysis and expansion of HSCs and thus suppress fibrogenesis, providing an original and effective approach for anti-fibrotic therapy. STATEMENT OF SIGNIFICANCE: Our work introduces an innovative antifibrotic drug system that is developed upon the active targeting of CPT and aims for the fate reversal of HSCs. Through HSC-targeted delivery achieved by PEG-PCL polymeric micelles decorated with vitamin A-derivatives, CPT significantly suppressed the expressions of HIF-1α and glycolytic enzymes in MF-HSCs, as well as their pathologic expansion in mouse livers. It effectively ameliorated chronic liver fibrosis in mice induced by CCl4 injection or BDL and restored the damaged liver structure and function. These compelling findings demonstrate the therapeutic potential of glycolytic HSC-targeting in combating fibrosis and related disorders and thus provide new promise for future clinical management of such prevalent and life-threatening conditions.

Emergent Peptides of the Antifibrotic Arsenal: Taking Aim at Myofibroblast Promoting Pathways

Myofibroblasts are the principal effector cells driving fibrosis, and their accumulation in tissues is a fundamental feature of fibrosis. Essential pathways have been identified as being central to promoting myofibroblast differentiation, revealing multiple targets for intervention. Compared with large proteins and antibodies, peptide-based therapies have transpired to serve as biocompatible and cost-effective solutions to exert biomimicry, agonistic, and antagonistic activities with a high degree of targeting specificity and selectivity. In this review, we summarize emergent antifibrotic peptides and their utilization for the targeted prevention of myofibroblasts. We then highlight recent studies on peptide inhibitors of upstream pathogenic processes that drive the formation of profibrotic cell phenotypes. We also briefly discuss peptides from non-mammalian origins that show promise as antifibrotic therapeutics. Finally, we discuss the future perspectives of peptide design and development in targeting myofibroblasts to mitigate fibrosis.

Liver Fibrosis Resolution: From Molecular Mechanisms to Therapeutic Opportunities

The liver is a critical system for metabolism in human beings, which plays an essential role in an abundance of physiological processes and is vulnerable to endogenous or exogenous injuries. After the damage to the liver, a type of aberrant wound healing response known as liver fibrosis may happen, which can result in an excessive accumulation of extracellular matrix (ECM) and then cause cirrhosis or hepatocellular carcinoma (HCC), seriously endangering human health and causing a great economic burden. However, few effective anti-fibrotic medications are clinically available to treat liver fibrosis. The most efficient approach to liver fibrosis prevention and treatment currently is to eliminate its causes, but this approach's efficiency is too slow, or some causes cannot be fully eliminated, which causes liver fibrosis to worsen. In cases of advanced fibrosis, the only available treatment is liver transplantation. Therefore, new treatments or therapeutic agents need to be explored to stop the further development of early liver fibrosis or to reverse the fibrosis process to achieve liver fibrosis resolution. Understanding the mechanisms that lead to the development of liver fibrosis is necessary to find new therapeutic targets and drugs. The complex process of liver fibrosis is regulated by a variety of cells and cytokines, among which hepatic stellate cells (HSCs) are the essential cells, and their continued activation will lead to further progression of liver fibrosis. It has been found that inhibiting HSC activation, or inducing apoptosis, and inactivating activated hepatic stellate cells (aHSCs) can reverse fibrosis and thus achieve liver fibrosis regression. Hence, this review will concentrate on how HSCs become activated during liver fibrosis, including intercellular interactions and related signaling pathways, as well as targeting HSCs or liver fibrosis signaling pathways to achieve the resolution of liver fibrosis. Finally, new therapeutic compounds targeting liver fibrosis are summarized to provide more options for the therapy of liver fibrosis.

An activatable near-infrared molecular reporter for fluoro-photoacoustic imaging of liver fibrosis

Noninvasive and accurate detection of liver fibrosis is extremely significant for well-timed intervention and treatment to prevent or reverse its progression. Fluorescence imaging probes hold great potential for imaging of liver fibrosis, but they always encounter the inherent limitation of shallow penetration depth, which compromises their ability of in vivo detection. To overcome this issue, an activatable fluoro-photoacoustic bimodal imaging probe (IP) is herein developed for specific visualization of liver fibrosis. The probe IP is constructed on a near-infrared thioxanthene-hemicyanine dye that is caged with gamma-glutamyl transpeptidase (GGT) responsive substrate and linked with integrin-targeted peptide (cRGD). Such molecular design permits IP to effectively accumulate in the liver fibrosis region through specific recognition of cRGD towards integrin and activate its fluoro-photoacoustic signal after interaction with overexpressed GGT to precisely monitor the liver fibrosis. Thus, our study presents a potential strategy to design dual-target fluoro-photoacoustic imaging probes for noninvasive detection of early-stage liver fibrosis.

Interdisciplinary advances reshape the delivery tools for effective NASH treatment

BACKGROUND

Nonalcoholic steatohepatitis (NASH), a severe systemic and inflammatory subtype of nonalcoholic fatty liver disease, eventually develops into cirrhosis and hepatocellular carcinoma with few options for effective treatment. Currently potent small molecules identified in preclinical studies are confronted with adverse effects and long-term ineffectiveness in clinical trials. Nevertheless, highly specific delivery tools designed from interdisciplinary concepts may address the significant challenges by either effectively increasing the concentrations of drugs in target cell types, or selectively manipulating the gene expression in liver to resolve NASH.

SCOPE OF REVIEW

We focus on dissecting the detailed principles of the latest interdisciplinary advances and concepts that direct the design of future delivery tools to enhance the efficacy. Recent advances have indicated that cell and organelle-specific vehicles, non-coding RNA research (e.g. saRNA, hybrid miRNA) improve the specificity, while small extracellular vesicles and coacervates increase the cellular uptake of therapeutics. Moreover, strategies based on interdisciplinary advances drastically elevate drug loading capacity and delivery efficiency and ameliorate NASH and other liver diseases.

MAJOR CONCLUSIONS

The latest concepts and advances in chemistry, biochemistry and machine learning technology provide the framework and strategies for the design of more effective tools to treat NASH, other pivotal liver diseases and metabolic disorders.

Hepatic Stellate Cell Targeting Using Peptide-Modified Biologicals

Liver diseases are a leading cause of death worldwide and are rising exponentially due to increasing prevalence of metabolic disorders. Hepatic stellate cells (HSCs) are recognized as a key therapeutic target in liver diseases as these cells, upon activation during liver damage and ongoing liver inflammation, secrete excessive amounts of extracellular matrix that leads to liver tissue scarring (fibrosis) responsible for liver dysfunction (end-stage liver disease) and desmoplasia in hepatocellular carcinoma. Targeting of HSCs to reverse fibrosis progression has been realized by several experts in the field, including us. We have developed strategies to target activated HSCs by utilizing the receptors overexpressed on the surface of activated HSCs. One well-known receptor is platelet derived growth factor receptor-beta (PDGFR-β). Using PDGFR-β recognizing peptides (cyclic PPB or bicyclic PPB), we can deliver biologicals, e.g., interferon gamma (IFNγ) or IFNγ activity domain (mimetic IFNγ), to the activated HSCs that can inhibit their activation and reverse liver fibrosis. In this chapter, we provide the detailed methods and the principles involved in the synthesis of these targeted (mimetic) IFNγ constructs. These methods can be adapted for synthesizing constructs for targeted/cell-specific delivery of peptides/proteins, drugs, and imaging agents useful for various applications including diagnosis and treatment of inflammatory and fibrotic diseases and cancer.

Peptide mediated therapy in fibrosis: Mechanisms, advances and prospects

Fibrosis, a disease characterized by an excess accumulation of extracellular matrix components, could lead to organ failure and death, and is to blame for up to 45 % of all fatalities in developed nations. These disorders all share the common trait of an unchecked and increasing accumulation of fibrotic tissue in the affected organs, which leads to their malfunction and eventual failure, even if their underlying causes are highly diverse and, in some cases, remain unclear. Numerous studies have identified activated myofibroblasts as the common cellular elements ultimately responsible for the replacement of normal tissues with nonfunctional fibrotic tissue. The transforming growth factor-β pathway, for instance, plays a significant role in practically all kinds of fibrosis. However, there is no specific drug for the treatment of fibrosis, several medications with anti-hepatic fibrosis properties are still in the research and development stages. Peptide, which refers to a substance consisting of 2-50 amino acids, is characterized by structural diversity, low toxicity, biological activities, easy absorption, specific targeting, few side effects, and has been proven to be effective in anti-fibrosis. Here, we summarized various anti-fibrosis peptides in fibrosis including the liver, lungs, kidneys, and other organs. This review will provide a new insight into peptide mediated anti-fibrosis and is helpful to creation of antifibrotic medications.

Breaking the niche: multidimensional nanotherapeutics for tumor microenvironment modulation

Most of the current antitumor therapeutics were developed targeting the cancer cells only. Unfortunately, in the majority of tumors, this single-dimensional therapy is found to be ineffective. Advanced research has shown that cancer is a multicellular disorder. The tumor microenvironment (TME), which is made by a complex network of the bulk tumor cells and other supporting cells, plays a crucial role in tumor progression. Understanding the importance of the TME in tumor growth, different treatment modalities have been developed targeting these supporting cells. Recent clinical results suggest that simultaneously targeting multiple components of the tumor ecosystem with drug combinations can be highly effective. This type of "multidimensional" therapy has a high potential for cancer treatment. However, tumor-specific delivery of such multi-drug combinations remains a challenge. Nanomedicine could be utilized for the tumor-targeted delivery of such multidimensional therapeutics. In this review, we first give a brief overview of the major components of TME. We then highlight the latest developments in nanoparticle-based combination therapies, where one drug targets cancer cells and other drug targets tumor-supporting components in the TME for a synergistic effect. We include the latest preclinical and clinical studies and discuss innovative nanoparticle-mediated targeting strategies.