ZBP1-mediated apoptosis and inflammation exacerbate steatotic liver ischemia-reperfusion injury.

There is increasing need to expand availability of donor liver grafts, including steatotic livers. However, the current use of steatotic grafts in liver transplantation is less acceptable due to their higher susceptibility to ischemia-reperfusion (I/R) injury. To investigate the mechanism underlying the susceptibility of steatotic liver to I/R injury, we detected cell death markers and inflammation in clinical donor livers and animal models. We found that caspase-8-mediated hepatic apoptosis is activated in steatotic liver I/R. However, ablation of caspase-8 only slightly mitigated steatotic liver I/R injury without affecting inflammation. We further demonstrated that RIPK1 kinase induces both caspase-8-mediated apoptosis and cell death-independent inflammation. Inhibition of RIPK1 kinase significantly protects against steatotic liver I/R injury by alleviating both hepatic apoptosis and inflammation. Additionally, we found that RIPK1 activation is induced by Z-DNA binding protein 1 (ZBP1) but not the canonical TNFα pathway during steatotic liver I/R. Deletion of ZBP1 substantially decreases the steatotic liver I/R injury. Mechanistically, ZBP1 is amplified by palmitic acid-activated JNK pathway in steatotic livers. Upon I/R, excessive reactive oxygen species trigger ZBP1 activation by inducing its aggregation independent of the Z-nucleic acids sensing action in steatotic livers, leading to the kinase activation of RIPK1 and the subsequent aggravation of liver injury. Thus, ZBP1-mediated RIPK1-driven apoptosis and inflammation exacerbate steatotic liver I/R injury, which could be targeted to protect steatotic donor livers during transplantation.

A NRF2 Regulated and the Immunosuppressive Microenvironment Reversed Nanoplatform for Cholangiocarcinoma Photodynamic-Gas Therapy.

Photodynamic therapy (PDT) is a minimally invasive and controllable local cancer treatment for cholangiocarcinoma (CCA). However, the efficacy of PDT is hindered by intratumoral hypoxia and the presence of an antioxidant microenvironment. To address these limitations, combining PDT with gas therapy may be a promising strategy to enhance tumor oxygenation. Moreover, the augmentation of oxidative damage induced by PDT and gas therapy can be achieved by inhibiting NRF2, a core regulatory molecule involved in the antioxidant response. In this study, an integrated nanotherapeutic platform called CMArg@Lip, incorporating PDT and gas therapies using ROS-responsive liposomes encapsulating the photosensitizer Ce6, the NO gas-generating agent L-arginine, and the NRF2 inhibitor ML385, is successfully developed. The utilization of CMArg@Lip effectively deals with challenges posed by tumor hypoxia and antioxidant microenvironment, resulting in elevated levels of oxidative damage and subsequent induction of ferroptosis in CCA. Additionally, these findings suggest that CMArg@Lip exhibits notable immunomodulatory effects, including the promotion of immunogenic cell death and facilitation of dendritic cell maturation. Furthermore, it contributes to the anti-tumor function of cytotoxic T lymphocytes through the downregulation of PD-L1 expression in tumor cells and the activation of the STING signaling pathway in myeloid-derived suppressor cells, thereby reprogramming the immunosuppressive microenvironment via various mechanisms.

Cell therapy for neuropathic pain.

Neuropathic pain (NP) is caused by a lesion or a condition that affects the somatosensory system. Pathophysiologically, NP can be ascribed to peripheral and central sensitization, implicating a wide range of molecular pathways. Current pharmacological and non-pharmacological approaches are not very efficacious, with over half of NP patients failing to attain adequate pain relief. So far, pharmacological and surgical treatments have focused primarily on symptomatic relief by modulating pain transduction and transmission, without treating the underlying pathophysiology. Currently, researchers are trying to use cell therapy as a therapeutic alternative for the treatment of NP. In fact, mounting pre-clinical and clinical studies showed that the cell transplantation-based therapy for NP yielded some encouraging results. In this review, we summarized the use of cell grafts for the treatment of NP caused by nerve injury, synthesized the latest advances and adverse effects, discussed the possible mechanisms to inform pain physicians and neurologists who are endeavoring to develop cell transplant-based therapies for NP and put them into clinical practice.

High PPT1 expression predicts poor clinical outcome and PPT1 inhibitor DC661 enhances sorafenib sensitivity in hepatocellular carcinoma.

BACKGROUND: Adaptive resistance and side effects of sorafenib treatment result in unsatisfied survival of patients with hepatocellular carcinoma (HCC). Palmitoyl-protein thioesterase 1 (PPT1) plays a critical role in progression of various cancers. However, its role on prognosis and immune infiltrates in HCC remains unclarified. METHODS: By data mining in the Cancer Genome Atlas databases, the role of PPT1 in HCC were initially investigated. Furthermore, HCC cell lines Hep 3B and Hep 1-6 were treated with DC661 or siRNA against PPT1. The biological function of PPT1 was determined by CCK-8 test, colony formation assay, TUNEL staining, immunofluorescence staining, Western blot test, and PI-Annexin V apoptosis assays in vitro. Animal models of subcutaneous injection were applied to investigate the therapeutic role of targeting PPT1. RESULTS: We found that PPT1 levels were significantly upregulated in HCC tissues compared with normal tissues and were significantly associated with a poor prognosis. Multivariate analysis further confirmed that high expression of PPT1 was an independent risk factor for poor overall survival of HCC patients. We initially found that PPT1 was significantly upregulated in sorafenib-resistant cell lines established in this study. Upon sorafenib treatment, HCC cells acquired adaptive resistance by inducing autophagy. We found that DC661, a selective and potent small-molecule PPT1-inhibitor, induced lysosomal membrane permeability, caused lysosomal deacidification, inhibited autophagy and enhanced sorafenib sensitivity in HCC cells. Interestingly, this sensitization effect was also mediated by the induction mitochondrial pathway apoptosis. In addition, the expression level of PPT1 was associated with the immune infiltration in the HCC tumor microenvironment, and PPT1 inhibitor DC661 significantly enhanced the anti-tumor immune response by promoting dendritic cell maturation and further promoting CD8+ T cell activation. Moreover, DC661 combined with sorafenib was also very effective at treating tumor models in immunized mice. CONCLUSIONS: Our findings suggest that targeting PPT1 with DC661 in combination with sorafenib might be a novel and effective alternative therapeutic strategy for HCC.

Chemo-photodynamic therapy with light-triggered disassembly of theranostic nanoplatform in combination with checkpoint blockade for immunotherapy of hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is a common malignant tumor with high rate of metastasis and recurrence. Although immune checkpoint blockade (ICB) has emerged as a promising type of immunotherapy in advanced HCC, treatment with ICB alone achieves an objective remission rate less than 20%. Thus, combination therapy strategies is needed to improve the treatment response rate and therapeutic effect. METHODS:  A light-triggered disassembly of nanoplatform (TB/PTX@RTK) co-loaded an aggregation induced emission (AIE) photosensitizer (TB) and paclitaxel (PTX) was prepared for on-command drug release and synergistic chemo-photodynamic therapy (chemo-PDT). Nano-micelles were characterized for drug loading content, hydrodynamic size, absorption and emission spectra, reactive oxygen species production, and PTX release from micelles. The targeted fluorescence imaging of TB/PTX@RTK micelles and the synergistic anti-tumor efficacy of TB/PTX@RTK micelles-mediated chemo-PDT combined with anti-PD-L1 were assessed both in vitro and in vivo. RESULTS: The TB/PTX@RTK micelles could specifically accumulate at the tumor site through cRGD-mediated active target and facilitate image-guided PDT for tumor ablation. Once irradiated by light, the AIE photosensitizer of TB could produce ROS for PDT, and the thioketal linker could be cleaved by ROS to precise release of PTX in tumor cells. Chemo-PDT could not only synergistically inhibit tumor growth, but also induce immunogenic cell death and elicit anti-tumor immune response. Meanwhile, chemo-PDT significantly upregulated the expression of PD-L1 on tumor cell surface which could efficiently synergize with anti-PD-L1 monoclonal antibodies to induce an abscopal effect, and establish long-term immunological memory to inhibit tumor relapse and metastasis. CONCLUSION: Our results suggest that the combination of TB/PTX@RTK micelle-mediated chemo-PDT with anti-PD-L1 monoclonal antibodies can synergistically enhance systemic anti-tumor effects, and provide a novel insight into the development of new nanomedicine with precise controlled release and multimodal therapy to enhance the therapeutic efficacy of HCC.