Granzyme B-responsive fluorescent probe for non-invasive early diagnosis of transplant rejection.

Allograft rejection has always been a major obstacle in organ transplantation. The current clinical diagnostic gold standard for allograft rejection is an invasive biopsy. However, biopsy has some limitations, such as sampling errors, risk of serious complications, and high cost. In this study, we have rationally developed an activatable fluorescent probe CYGB for imaging of granzyme B, which is a biomarker released by CD8+T cells attacking the graft. Moreover, the ability of CYGB to detect rejection early in mouse heart and skin transplantation models was evaluated. The probe CYGB consists of a caged hemicyanine-based fluorophore and a GzmB-specifically cleaved peptide substrate linked via a self-immolating spacer, p-aminobenzyl alcohol. Endogenous GzmB in CD8+ T cells specifically activated the near-infrared fluorescence (NIRF) signal of CYGB. In vivo imaging in mice skin and heart graft models, showed that CYGB preferentially accumulates in grafts, enabling early diagnosis of rejection. Moreover, CYGB enables non-invasive assessment of the level of immunosuppression in allogeneic mice treated with FK506. This study provides an alternative method for monitoring the status of allografts without biopsy.

Targeted microRNA delivery by lipid nanoparticles and gas vesicle-assisted ultrasound cavitation to treat heart transplant rejection.

Despite exquisite immune response modulation, the extensive application of microRNA therapy in treating heart transplant rejection is still impeded by poor stability and low target efficiency. Here we have developed a low-intensity pulsed ultrasound (LIPUS) cavitation-assisted genetic therapy after executing the heart transplantation (LIGHT) strategy, facilitating microRNA delivery to target tissues through the LIPUS cavitation of gas vesicles (GVs), a class of air-filled protein nanostructures. We prepared antagomir-155 encapsulated liposome nanoparticles to enhance the stability. Then the murine heterotopic transplantation model was established, and antagomir-155 was delivered to murine allografted hearts via the cavitation of GVs agitated by LIPUS, which reinforced the target efficiency while guaranteeing safety owing to the specific acoustic property of GVs. This LIGHT strategy significantly depleted miR-155, upregulating the suppressors of cytokine signaling 1 (SOCS1), leading to reparative polarization of macrophages, decrease of T lymphocytes and reduction of inflammatory factors. Thereby, rejection was attenuated and the allografted heart survival was markedly prolonged. The LIGHT strategy achieves targeted delivery of microRNA with minimal invasiveness and great efficiency, paving the way towards novel ultrasound cavitation-assisted strategies of targeted genetic therapy for heart transplantation rejection.

First aggregation-induced emission-active probe for species-specific detection of ß-galactosidase.

Sensitive detection of ß-galactosidase (ß-gal) is of great significance for early diagnosis of ovarian cancer. Fluorescent probes for detecting ß-gal have received great interest due to the non-invasiveness, excellent sensitivity, high temporal, and superior spatial resolution. However, most reported fluorescent sensors for ß-gal suffer from aggregation caused quenching effect when accumulated, and cannot discriminate ß-gal from other species, especially, Escherichia coliß-gal. Herein, we report the first aggregation-induced emission (AIE)-active fluorescent probe HBTTPAG, which achieves species-selective detection of ß-gal. Probe HBTTPAG can discriminate Aspergillus oryzae ß-gal from Escherichia coliß-gal, with high sensitivity (detection limit of 3.7 × 10-3 UmL-1), superior selectivity and low cytotoxicity. Furthermore, HBTTPAG is utilized to visualize endogenous ß-gal in lysosomes of SKOV-3 cells, as well as to detect ß-gal activity in ovarian cancer tissues. Notably, owing to the AIE-active, HBTTPAG realizes long-term (12 h) tracking ß-gal in ovarian cancer cells. This work provides a promising method for species-selective detection of ß-gal in preclinical.

Biomimetic Glucan Particles with Aggregation-Induced Emission Characteristics for Noninvasive Monitoring of Transplant Immune Response.

Real-time monitoring of post-transplant immune response is critical to prolong the survival of grafts. The current gold standard for assessing the immune response to graft is biopsy. However, such a method is invasive and prone to false negative results due to limited tissue size available and the heterogeneity of the rejection site. Herein, we report biomimetic glucan particles with aggregation-induced emission (AIE) characteristics (HBTTPEP/GPs) for real-time noninvasive monitoring of post-transplant immune response. We have found that the positively charged near-infrared AIEgens can effectively aggregate in the confined space of glucan particles (GPs), thereby turning on the fluorescence emission. HBTTPEP/GPs can track macrophages for 7 days without hampering the bioactivity. Oral administration of HBTTPEP/GPs can specially target macrophages by mimicking yeast, which then migrate to the transplant rejection site. The fluorescence emitted from HBTTPEP/GPs correlated well with the infiltration of macrophages and the degree of allograft rejection. Furthermore, a single oral HBTTPEP/GPs dose can dynamically evaluate the therapeutic response to immunosuppressive therapy. Consequently, the biomimetic AIE-active glucan particles can be developed as a promising probe for immune-monitoring in solid organ transplantation.

Resolvin E1 reduces hepatic fibrosis in mice with Schistosoma japonicum infection.

The aim of this study was to investigate whether resolvin E1 (RvE1) protects against hepatic fibrosis in a murine model of liver fibrosis induced by Schistosoma japonicum infection. A total of 30 pathogen-free Kunming mice were randomly and equally divided into three groups: Control (uninfected, untreated), model (infected, untreated) and RvE1 intervention (infected, RvE1-treated; 100 ng daily). The mice were infected with Schistosoma japonicum by inoculating the abdominal skin with 20±2 cercariae to induce models of liver fibrosis. The area and numbers of the granulomas in the livers were assessed through histopathology after 70 days of treatment. The levels of tumor necrosis factor (TNF)-α and interferon (IFN)-γ were evaluated in the serum by enzyme-linked immunosorbent assay (ELISA). The expression levels of TNF-α were detected in the hepatic tissue by reverse transcription-polymerase chain reaction and western blot analysis. The activity levels of alanine aminotransferase and aspartate aminotransferase were determined in the serum by ELISA. The expression levels of laminin (LN), hyaluronic acid (HA), procollagen type III (PC-III) and type IV collagen (IV-C) were detected in the serum by radioimmunoassays. The results revealed that the mean area of the granulomas was smaller in the RvE1 intervention group compared with that in the model group. Following RvE1 treatment, the serum levels of TNF-α were lower than those in the model group, while the serum levels of IFN-γ were higher compared with those in the model group. The expression levels of TNF-α were lower in the hepatic tissue following RvE1 treatment compared with those in the model group. The indicators of liver fibrosis, the levels of LN, HA, PC-III and IV-C in the serum, were lower following RvE1 treatment than those in the model group. In conclusion, RvE1 treatment may reduce the growth of granulomas, thereby slowing the process of hepatic fibrosis, and this effect may be the result of anti-inflammatory and immune system adjustment.