Background: Neuroinflammation is a vital pathophysiological process during ischemic stroke. Activated astrocytes play a major role in inflammation. Lipocalin-2 (LCN2), secreted by activated astrocytes, promotes neuroinflammation. Pyroptosis is a pro-inflammatory form of programmed cell death that has emerged as a new area of research in stroke. Nevertheless, the potential role of LCN2 in astrocyte pyroptosis remains unclear. Methods: An ischemic stroke model was established by middle cerebral artery occlusion (MCAO) in vivo. In this study, in vitro, oxygen–glucose deprivation and reoxygenation (O/R) were applied to cultured astrocytes. 24p3R (the LCN2 receptor) was inhibited by astrocyte-specific adeno-associated virus (AAV-GFAP-24p3Ri). MCC950 and Nigericin sodium salt (Nig) were used to inhibit or promote the activation of NLRP3 inflammasome pharmacologically, respectively. Histological and biochemical analyses were performed to assess astrocyte and neuron death. Additionally, the neurological deficits of mice were evaluated. Results: LCN2 expression was significantly induced in astrocytes 24 h after stroke onset in the mouse MCAO model. Lcn2 knockout (Lcn2^−/−) mice exhibited reduced infarct volume and improved neurological and cognitive functions after MCAO. LCN2 and its receptor 24p3R were colocalized in astrocytes. Mechanistically, suppression of 24p3R by AAV-GFAP-24p3Ri alleviated pyroptosis-related pore formation and the secretion of pro-inflammatory cytokines via LCN2, which was then reversed by Nig-induced NLRP3 inflammasome activation. Astrocyte pyroptosis was exacerbated in Lcn2^−/− mice by intracerebroventricular administration of recombinant LCN2 (rLCN2), while this aggravation was restricted by blocking 24p3R or inhibiting NLRP3 inflammasome activation with MCC950. Conclusion: LCN2/24p3R mediates astrocyte pyroptosis via NLRP3 inflammasome activation following cerebral ischemia/reperfusion injury.

Circulating microRNAs (miRNAs) are emerging as clinically useful tools for cancer detection; however, little is known about their early diagnostic impact on RCC. The levels of 754 serum miRNAs were initially determined using a TaqMan Low Density Array in two pooled samples from 25 RCC and 25 noncancer controls. Markedly dysregulated miRNAs in RCC cases were subsequently validated individually by qRT-PCR in another 107 patients and 107 controls arranged in two sets. The serum levels of miR-193a-3p, miR-362 and miR-572 were significantly increased whereas the levels of miR-28-5p and miR-378 were markedly decreased in patients with RCC, even in those with stage I disease, compared with the noncancer controls (P < 0.01). The areas under the ROC curve (AUCs) for the 5 combined miRNAs were 0.807 (95% CI, 0.687–0.928) and 0.796 (95% CI, 0.724–0.867) for the training set and the validation set, respectively. Furthermore, the panel enabled the differentiation of stage I RCC from controls with AUC of 0.807 (95% CI, 0.731–0.871), a sensitivity of 80% and a specificity of 71%. This panel of 5 serum miRNA may have the potential to be used clinically as an auxiliary diagnostic tool for the early detection of RCC.

Dysregulation of small non‐coding RNA (ncRNA) is associated with various human diseases including cancer. This study aimed to evaluate the circulating exosomal small RNAs including microRNAs (miRNAs) and P‑element‑induced wimpy testis (PIWI)‐interacting RNAs (piRNAs) as sensitive and specific non‐invasive biomarkers for gastric cancer (GC) diagnosis. Serum exosomal small RNA transcriptome was examined using unique molecular identifiers (UMI) small RNA sequencing. Dysregulated miRNAs and piRNAs were verified in 70 GC patients and 60 healthy controls (HC) by reverse transcription quantitative PCR. The expressions of miR‐1307‐3p, piR‐019308, piR‐004918 and piR‐018569 in serum exosomes were significantly increased in GC group as compared to those in HC group. Moreover, GC patients with metastasis had significantly higher expression levels of piR‐004918 and piR‐019308 than GC patients without metastasis. The area under the curve (AUC) for miR‐1307‐3p, piR‐019308, piR‐004918 and piR‐018569 in the GC group was 0.845, 0.820, 0.754 and 0.732, respectively. The combination of carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 199 can improve the AUC of miR‐1307‐3p to 0.902 and piR‐019308 to 0.914 for GC diagnosis. In conclusion, our findings indicate that serum exosomal piRNAs are promising non‐invasive diagnostic biomarkers for GC patients and potential markers for monitoring metastasis.

Dysregulation of N⁶‐methyladenosine (m⁶A) is associated with various human diseases including cancer. This study aimed to evaluate the level of m⁶A as a biomarker for gastric cancer (GC) diagnosis. Peripheral blood samples were collected from 100 GC patients, 30 benign gastric disease (BGD) patients, and 75 healthy controls (HCs). Levels of m⁶A in total RNA and expression of m⁶A-related proteins were analyzed. The m⁶A levels in peripheral blood RNA were significantly increased in the GC group compared with those in the BGD or HC groups; moreover, levels increased with the progression and metastasis of GC and decreased in GC patients after surgery. The area under the curve (AUC) for m⁶A in the GC group was 0.929 (95% CI, 0.88–0.96), which is markedly greater than the AUCs for carcinoembryonic antigen (CEA; 0.694) and carbohydrate antigen 199 (CA199; 0.603). The combination of CEA and CA199 with m⁶A improved the AUC to 0.955 (95% CI, 0.91–0.98). The expressions of m⁶A demethylases ALKBH5 and FTO were significantly downregulated in the GC group compared with the HC group. Coculture with GC cells increased the m⁶A of RNA in promyelocytic (HL-60) and monocytic (THP-1) leukemia cells and nontumorigenic human peripheral blood B lymphocyte cells (PENG-EBV). Furthermore, a xenograft model enhanced the m⁶A in peripheral blood RNA of mice. Accordingly, expressions of ALKBH5 and FTO were decreased both in vitro and in vivo. Level of m⁶A in peripheral blood RNA is a promising noninvasive diagnostic biomarker for GC patients.