Current Status in Rechallenge of Immunotherapy

The treatment of malignant tumors has entered the era of immunotherapy, and immune checkpoint inhibitors (ICIs) have brought significant benefits to patients. However, some patients are required to discontinue treatment with ICIs owing to factors such as disease progression and intolerable side effects. Faced with limited subsequent treatment options and complex medical needs, we searched PubMed, Embase, Cochrane library, and the NIH clinical trials database and found that ICI rechallenge could be a relevant clinical strategy. The factors that could affect the rechallenge efficacy include the patients' characteristics, therapeutic strategy selection, and the timing of treatment. Multiple factors are used to identify target population, of which clinical features and PD-L1 expression are more potential. Both single ICI rechallenge and combination therapy may have survival benefits. Patients who have tolerated initial immunotherapy well could undergo ICI rechallenge, while patients who have experienced grade 3 or higher immune-related adverse events should be carefully assessed prior to rechallenge. Interventions and the interval between two courses of ICI will clearly have an impact on the efficacy of subsequent treatment. Preliminary data evaluation supports further investigation on ICI rechallenge to identify the factors that could contribute to its efficacy.

HSP90 pathway in intermediate mononuclear cells causes plaque erosion via induction of neutrophil hyper-responsiveness

Aim

To explore the function(s) of HSP90 in intermediate monocyte-mediated plaque erosion.

Materials and methods

We used single-cell RNA sequencing to map cardiac immune response composition in patients with plaque rupture and plaque erosion. By focusing our analyses on CD14 positive monocytes, we obtained a higher resolution identification of the immune cell subsets in patients experiencing plaque erosion and rupture. We interpreted our findings with analyses using gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases and by performing receiver operating characteristic (ROC) curve analysis.

Results

Single-cell sequencing analysis of mononuclear cells in the peripheral blood of five ACS patients experiencing plaque erosion and rupture confirmed that CD14 positive monocytes were the main immune cells leading to ACS. Interestingly, our results suggested a significant increase in the proportion of atypical monocytes (C4 subsets) in patients with plaque rupture, which was a novel finding. This increase may be caused by increased migration of atypical monocytes into a plaque during plaque rupture. We found that intermediate monocyte activation was most obvious in patients with plaque erosion (C1, C10, and C11), and the proportion of C1 subgroup monocytes (FCGR3B/CMTM2 double strong positive; subsequently defined as intermediate monocytes) was very high. To further explore the role of C1 subgroup intermediate monocytes in plaque erosion, GO and KEGG pathway analyses were performed. GO analysis indicated that C1 subgroup intermediate monocytes are highly involved in neutrophil metabolism. Because neutrophils are the main effector cells that induce plaque erosion, we reasonably infer that intermediate monocytes can induce plaque erosion. KEGG pathway analysis indicated that all subtypes of HSP90 were highly expressed in C1 subgroup intermediate monocytes. We thus collected peripheral blood from ACS patients with plaque rupture (n=150) and plaque erosion (n=150) for mononuclear cell transcriptomics and intracellular proteomics analysis. ROC curve analysis demonstrated that the area under the curve for HSP90-based prediction was 0.86, indicating that HSP90 could be used to predict if patients would experience plaque erosion.

Conclusion

Activation of intermediate mononuclear HSP90 expression may be the crucial event that induces neutrophil hyper-responsiveness and leads to plaque erosion.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): China,Shanghai Science and Technology Commission

Identification of a glutathione S-transferase gene of Physarum polycephalum as a biomarker for nanosized TiO2 exposure under dark conditions

In this study, a glutathione S-transferase gene (gst) from sensitive Physarum polycephalum was selected for its ability to detect nanosized TiO₂ (nTiO₂ ) exposure under dark conditions. The concentration of nTiO₂ (25, 40 and 60 nm) for subsequent assays was first determined (5-18 mg ml^-1 ) and total GST enzyme activity of P. polycephalum was confirmed to be increased 6-44 fold in groups treated with nTiO₂ . Second, an RNA-seq study was performed to identify candidate gst genes before isolation of an optimum gst gene of P. polycephalum (Ppgst), which encoded 223 amino acids. Third, the transcriptional level of the Ppgst gene was further confirmed to be positively correlated with nTiO₂ exposure within the concentration range of (5-15 mg ml^-1 ) by qPCR. In conclusion, these results indicated that the transcriptional level of Ppgst can reflect nTiO₂ exposure, suggesting that it may be employed as a new biomarker for nTiO₂ pollution under dark conditions.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study identifies a new gst gene for indicating nanosized TiO₂ under dark conditions and provides a new option for detection of nanosized TiO₂ pollution under dark conditions.

The production characteristics of volatile organic compounds and their relation to growth status of Staphylococcus aureus in milk environment

In our previous research, 3-methyl-butanal and 3-methyl-butanoic acid were identified as representative and specific volatile organic compounds released by Staphylococcus aureus in broth. In this study, we explored the production of the 2 volatiles and their correlation to Staph. aureus growth in milk under different conditions. We found significant correlations between the production of 3-methyl-butanoic acid and cell counts of 5 Staph. aureus strains in sterile milk, and there were no obvious differences for its production among 5 tested strains. The intensities of the 2 volatiles were similar and positively correlated with bacterial counts in cultures at 25°C and 37°C despite delayed production of volatiles at 25°C; however, neither compound could be detected at 4°C. The production of 3-methyl-butanoic acid was strongly correlated with growth of Staph. aureus mixed with Streptococcus agalactiae, Escherichia coli O157:H7, and Shigella flexneri, whereas correlations for 3-methyl-butanal were not statistically significant. Compared with the monoculture of Staph. aureus, in mixed cultures, production of 3-methyl-butanal was decreased and that of 3-methyl-butanoic acid was comparatively higher. In pasteurized and raw milks, production of 3-methyl-butanoic acid was correlated with growth of Staph. aureus, and 3-methyl-butanoic acid could be detected when Staph. aureus populations reached 10⁶ to 10⁷ cfu/mL in pasteurized milk and 10⁵ to 10⁶ cfu/mL in raw milk; the correlations for 3-methyl-butanal were not statistically significant. Our results suggest that 3-methyl-butanoic acid is a more suitable marker for high counts of Staph. aureus in milk, whereas 3-methyl-butanal is a transient metabolite and easily depressed by environmental factors.