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In situ cell imaging plays a crucial role in studying physiological and pathological processes of cells. Proximity ligation assay (PLA) and rolling circle amplification (RCA) are commonly used to study the abundance and interactions of biological macromolecules. The most frequently applied strategy to visualize the RCA products is with single-fluorophore probe, however, cellular auto-fluorescence and unbound fluorescent probes could interfere with RCA products, leading to non-specific signals. Here, we present a novel approach combining aptamer mediated PLA, RCA, and Förster Resonance Energy Transfer (FRET), namely Apt-PLA-RCA-FRET, for sensitive in situ imaging and analysis of the abundances and interactions of membrane proteins such as tetraspanin CD63 and human epidermal growth factor receptor 2 (HER2). Apt-RCA-FRET was initially designed to show its ability to assess the abundance of target proteins on different cells. Dual functional oligonucleotides served as both the aptamer for recognizing specific membrane proteins and the primer of circular DNA for following RCA process, and the resulting RCA products were subsequently imaged by FRET signals from Cy3 to Cy5 probes which hybridized sequentially on them. FRET was demonstrated to show its great potential to resist the interferences of nonspecific fluorescence compared to single-fluorophore strategies. PLA was then introduced to Apt-RCA-FRET to investigate the spatial localization of different proteins on cell membrane and their interactions. Our approach utilizing aptamer as membrane proteins recognition element simply converted the abundance of proteins into nucleic acid signals and facilitated the following signal amplification, thus it serves as an important alternative to methods typically based on antibody and presents a more robust and sensitive method for analyzing the abundances of different cell membrane proteins and their spatial localization, which offers valuable insights into physiological and pathological processes of cells., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier B.V. All rights reserved.)

Hemophagocytic lymphohistiocytosis (HLH) in different ethnicities has been described in the literature, but few cases in patients of Chinese descent have been reported. Here, we describe the case of a Chinese neonate presenting with HLH carrying novel, compound heterozygous mutations of the UNC13D gene, including [c.2295_2298delGCAG, p.Glu765Aspfs*27] in exon 23, c.-250C>T, c.1+30G>A, c.279C>T, c.888G>C, c.18+36A>G, c.20-48T>C, c.1977C>T, c.2296C>T, c.24-46C>T, c.26-9_26-8insC, c.2599A>G, c.28+48C>T and c.3198A>G, some of which have not been reported in the literature. Cytokine profile analyses were performed in this patient, and the results were consistent with our previous findings in HLH patients. Cytokine profile monitoring may be helpful in differentiating among various clinical phases of HLH.

Background: Recent studies have found that programmed death ligand 1 (PD‐L1) might be involved in chemotherapy resistance in non‐small cell lung cancer (NSCLC). Arsenic sulfide (As4S4) has been recognized to have antitumor activities and enhance the cytotoxic effect of chemotherapy drugs. In this study, we aimed to verify the relationship between PD‐L1 and cisplatin (DDP) resistance and identify whether As4S4 could reverse DDP resistance through targeting PD‐L1 in NSCLC. Methods: The effect of As4S4 and DDP on cell proliferation and apoptosis was investigated in NSCLC cell lines. The expression of p53 and PD‐L1 proteins was measured by western blotting analysis. The levels of miR‐34a‐5p, miR‐34a‐3p and PD‐L1 in cells were measured by real‐time qPCR analysis. Mouse xenograft models were established by inoculation with A549/DDP (DDP‐resistant) cells. Results: Depletion of PD‐L1 inhibited DDP resistance in A549/DDP and H1299/DDP cells. As4S4 was capable of sensitizing A549/DDP cells to DDP by enhancing apoptosis. As4S4 upregulated p53 expression and downregulated PD‐L1 expression in A549/DDP cells. As4S4 increased miR‐34a‐5p level in A549/DDP cells. Inhibition of p53 by PFT‐α partially restored the levels of PD‐L1 and miR‐34a‐5p. Pretreatment with PFT‐α suppressed the apoptosis rate induced by cotreatment of As4S4 and DDP in A549/DDP cells. Cotreatment of DDP and As4S4 notably reduced the tumor size when compared with DDP treatment alone in vivo. Conclusions: Upregulation of PD‐L1 was correlated with DDP resistance in NSCLC cells. Mechanistic analyses indicated that As4S4 might sensitize NSCLC cells to DDP through targeting p53/miR‐34a‐5p/PD‐L1 axis. [ABSTRACT FROM AUTHOR]