Hexabromocyclododecane (HBCD) induced PANoptosis of chondrocytes via activation of the NLRP3 inflammasome and decreased the exercise ability of mice in vivo.

Hexabromocyclododecane (HBCD) is a persistent organic pollutant (POP). HBCD is found in the blood and tissues of most populations and causes a range of toxicological damage to tissues and cells. However, the toxicological effects of HBCD on chondrocytes are not fully understood. Here, we evaluated the toxicological effects of HBCD on chondrocytes and cartilaginous tissue. For this, a model of primary cartilage cells was established. Chondrocytes were exposed to different concentrations of HBCD. Western blot, indirect immunofluorescence, ELISA and other biochemical experiments were performed to analyze the toxicological effects of HBCD on chondrocytes/articular cartilage tissue. Cell proliferation assays showed that HBCD caused a reduction in the proliferative capacity of chondrocytes, and further work indicated that HBCD induces chondrocyte death. Further experiments demonstrated that HBCD caused an inflammatory response in chondrocytes by evaluating the levels of inflammatory factors. We found that HBCD led to PANoptosis in chondrocytes by detecting panapoptosis-related marker molecules, and experimental data indicated that apoptosis markers (cleaved caspase-3/7), pyroptosis markers (caspase-1/GSDMD-N) and necroptosis markers (pMLKL/RIPK3) were upregulated after HBCD treatment. Subsequent experiments illustrated that HBCD activated the DAMP sensor NLRP3, which then mediated ZBP1-induced PANoptosis. In the in vivo model, the experimental animals were administered HBCD at 25, 50 and 100 µg/kg/week for 15 weeks. We found that HBCD led to an inflammatory response in articular cartilage tissue. The safranin O-fast green assay showed a certain degree of damage to cartilage tissue under HBCD treatment. Furthermore, HBCD resulted in an increase in MMP13 expression and a downregulation of COL2 expression in chondrocytes/cartilaginous tissues. HBCD decreased the exercise ability of mice in vivo. These data indicate that HBCD leads to chondrocyte damage. In summary, this study lays the foundation for further exploration of the toxicological effects of HBCD on bone and joints.

Optimal fluorescence and photosensitivity properties of dual-functional NaYb1-x F4:Tm x 3+ nanoparticles for applications in imaging guided photodynamic therapy.

The fluorescence and photosensitivity properties of NaYb1-x F4:Tm x 3+ nanoparticles were optimized to develop noninvasive near-infrared fluorescence imaging-guided photodynamic therapy. The emission at 800 nm from Tm3+ presented an exponential increase with an increase in the Tm3+ doping concentration from 0 to 2%. The photosensitivity properties of NaYb1-x F4:Tm x 3+ nanoparticles were also studied via the chemoprobe method, which used a reactive oxygen quencher, 1,3-diphenylisobenzofuran (DPBF). With the increase in the doping concentration of Tm3+, the generation rate of reactive oxygen species in NaYb1-x F4:Tm x 3+ nanoparticles decreased linearly at a rate of 0.3. The doping concentration of Tm3+ had two opposite effects on the 800 nm emission and generation rates of reactive oxygen species. The competitive relationship was discussed and an optimal value for the Tm3+ doping concentration of approximately 1% was determined. At this concentration, the energy of the Yb3+ excited state can be fully utilized, and the fluorescence and photosensitivity properties are an effective combination.

First Report of Botryosphaeria dothidea Causing Stem Canker and Dieback of Gleditsia sinensis in China.

Gleditsia Sinensis Lam is a kind of legume perennial woody plant, which is a traditional Chinese medicine with high economic and ecological value. Its planting area is about 0.1 million ha. In July 2018, symptoms of stem blight were observed on G. sinensis in An shun (26.072311°N, 106.097433°E), Guizhou province (southwestern China). Symptoms included stem canker and dieback, twig blight and extensive vascular discoloration, with incidence rate of 45 to 70%. Samples from plants with symptoms were washed with running tap water, surface sterilized with 2% sodium hypochlorite and then 75% ethanol, rinsed in sterile distilled water, plated on potato dextrose agar (PDA) and incubated at 28°C. Fungal isolates developed copious white aerial mycelium that became dark grey after four to five days, and formed black pycnidia after 23 days. Single hyphal tip cultures of putative 27 isolates were stored in the culture collection (CMW) of the Urban Modern Agriculture Engineering Research Center at the Kunming University. Conidia forming on pycnidia were one-celled, hyaline, aseptate, and fusiform, with dimensions of 20.3-25.9 µm x 4.2-6.5 µm (average 22.5 x 5.5 µm) (sixty conidia were measured). DNA sequence analysis of the ribosomal internal transcribed spacer regions ITS1-5.8S-ITS4, ß-tubulin, and the translation elongation factor 1-alpha (EF1-α) were performed. BLAST searches at GenBank showed the highest nucleotide sequence identity with Botryosphaeria dothidea reference sequence (ITS: >99.82%, KR708996; EF1-α: 99.62%, KP183214; ß-tubulin: > 99.67%, KU306116). Representative sequences of isolates from these regions were deposited in GenBank (ITS: Accession No. MT449017; EF1-α: Accession No. MT454342; ß-tubulin: Accession No. MT454343). Morphological and molecular results confirmed this species as B. dothidea (Aguirre et al. 2018). Pathogenicity tests were conducted by stem inoculation of two-year-old G. sinensis seedlings. Mycelial plugs (2-3 mm in diameter) from actively growing colonies of B. dothidea (PDA) were applied to same-size bark wounds on the middle point of the stems. Inoculated wounds were wrapped with Parafilm. Control seedlings received sterile PDA plugs. Inoculated and control seedlings (9 each), and kept in the greenhouse (28℃, 80% humidity); After 10 days, all of the inoculated plants showed dark vascular stem tissue, and the controls remained healthy. After 30 days, all of the inoculated but none of the control G. sinensis seedlings showed leaf wilting and tissue discoloration. B. dothidea was re-isolated from symptomatic tissues, thus fulfilling Koch's postulates. No symptoms were visible in the control seedlings, and no B. dothidea was re-isolated from the control seedlings tissues. B. dothidea is a member of Botryosphaeriaceae, commonly associated with cankers and dieback of woody plants. B. dothidea has been reported as a pathogen causing stem dieback and branch canker on Malosma laurina (Aguirre et al. 2018), Helwingia chinensis (Yu et al. 2012), and blueberry (Choi 2011; Yu et al. 2012). To our knowledge, this is the first report of B. dothidea on G. sinensis in China.