Background Diabetes ulcer is one of the leading causes of disability and death in diabetics. Y8 [(2-(2-fluoro-4-((4-methyl-2-(4-(trifluoromethyl)phenyl)thiazol-5-yl)methoxy) phenoxy)acetic acid)], a dual agonist of peroxisome proliferation activated receptorβ (PPARβ) and free fatty acid receptor 1 (FFA1/FFAR1/GPR40), a new compound molecule with the potential for diabetes ulcer treatment. Objective To research the effect of the dual target agonist Y8 and its mechanism of action in the treatment of diabetic ulcers. Methods We have established a wound model in diabetic mice. After treatment with Y8, wound healing was evaluated by tissue pathology, reactive oxygen species (ROS) levels, and gene expression testing. Under high sugar conditions, the mechanism of Y8 affecting fibroblasts' proliferation and keratinocytes' migration is further studied. Results We found that Y8 accelerated wound healing and shortened healing time in diabetic mice. Granulation tissue generation and extracellular matrix (ECM) deposition were significantly increased in Y8-treated mice. Mechanistically, Y8 promotes keratinocyte proliferation by activating PPARβ and migration of keratinocytes by triggering FFA1 in vitro. In addition, Y8 also decreased ROS levels in fibroblasts in vitro and in vivo by activating PPARβ, reducing their release of superoxide anions. Conclusion Our results suggest that PPARβ/FFA1 dual agonist Y8 has the effect of promoting the healing of diabetic ulcer wounds in vivo and in vitro, and its therapeutic effect is better than that of single-target agonists.
Immunotherapy is often less effective for tumors with “immune-excluded,” or “immune-desert” microenvironment. To circumvent this hurdle, new therapeutic strategies need to be designed to reprogram the tumor microenvironment (TME). It is well known that photothermal therapy (PTT) can prime the TME and provoke the systemic anti-tumor immunity. But few studies perform extensive exploration in depth to decipher the changes in TME after PTT with cutting-edge technology besides conventional flow cytometry analysis. In this study, we designed a nanosystem consisting of organic semiconductor polymer liposome nanoparticles (Y8 NPs) as a multimodal imaging and photothermal agent to image and treat tumors. Upon laser irradiation, Y8 NPs in tumors could rapidly increase the temperature, induce massive cancer cell apoptosis and also promote the immunogenic cell death (ICD), ultimately remodulating the TME. We employed single cell RNA sequencing (scRNA-seq) technology to comprehensively explore transcriptomic profiling of individual cells constituting TME, demonstrating heterogenous alterations in the subtypes of immune cells, even tumor cells. Considering the findings by scRNA-seq and TME remodulation, the combinational strategy with checkpoint blockade PD-1 antibody was designed to treat the tumors, demonstrating that the combination not only impedes primary tumor progression but also produce profound abscopal anti-tumor effect. In conclusion, we provide a simple strategy for the remodulation of TME with a photothermal nanosystem to achieve activation of anti-tumor immunity, and suppress primary and metastatic tumor progression.