Yingwu Mei

Recent studies have established a strong association between the cerebellum and various psychiatric disorders, as well as drug addiction and withdrawal processes. However, the mechanisms underlying the cerebellum's role in nicotine withdrawal symptoms have yet to be explored. In this study, we employed transcriptome sequencing, untargeted metabolomics and integrative multi‐omics analysis to elucidate the molecular mechanisms underlying nicotine withdrawal‐induced affective symptoms, specifically anxiety and depression‐like behaviours, within the cerebellum. Our findings demonstrate that enhanced purine metabolism and disrupted arginine metabolism in the cerebellum significantly contribute to the development of anxiety and depression‐like behaviours in mice undergoing nicotine withdrawal. Treatment with the non‐selective adenosine receptor antagonist, theobromine, markedly alleviates these behaviours. This mechanism likely involves inhibiting adenosine signalling and restoring arginine metabolism in the cerebellum.

Immune checkpoint inhibitors (ICIs), particularly PD-1/PD-L1 blockade, have shown great success in treating melanoma. PD-L1 (B7-H1, CD274), a ligand of PD-1, binds to PD-1 on T cells, inhibiting their activation and proliferation through multiple pathways, thus dampening tumor-reactive T cell activity. Studies have linked PD-L1 expression in melanoma with tumor growth, invasion, and metastasis, making the PD-1/PD-L1 pathway a critical target in melanoma therapy. However, immune-related adverse events are common, reducing the effectiveness of anti-PD-L1 treatments. Recent evidence suggests that the gut microbiome significantly influences anti-tumor immunity, with the microbiome potentially reprogramming the tumor microenvironment and overcoming resistance to anti-PD-1 therapies in melanoma patients. This review explores the mechanisms of PD-1/PD-L1 in melanoma and examines how gut microbiota and its metabolites may help address resistance to anti-PD-1 therapy, offering new insights for improving melanoma treatment strategies.

Circular RNA (circRNA) has garnered significant attention as a promising therapeutic tool due to its remarkable stability and resistance to exonuclease degradation. However, the development of scalable and efficient purification methods remains a critical challenge. In this study, we propose and evaluate a novel purification strategy for engineered circular RNA (PAPdt), which leverages poly(A) polymerase and oligo(dT) affinity chromatography. Using poly(A) polymerase, we add poly(A) tails of over 200 nucleotides to the 3’-OH ends of all linear RNA impurities in a circular RNA preparation. These linear RNAs are then separated from the circular RNA via oligo(dT) affinity chromatography. The linear impurities, bearing longer poly(A) tails, exhibit extended retention on the oligo(dT) column, whereas the circular RNA, with a shorter poly(A) sequence, elutes more quickly. By stepwise elution with ultrapure water, we effectively separate the circular RNA from the linear contaminants. This method offers a fundamental solution to the purification of circular RNA, combining high efficiency, purity, and cost-effectiveness.

Sequential window acquisition of all theoretical spectra (SWATH) as a typical data-independent acquisition (DIA) strategy is favorable for untargeted metabolomics. It could theoretically acquire product ions of all precursor ions, including precursor ions showing chromatographic peaks of rather poor qualities. However, existing data processing methods present limited capabilities in capturing poor-quality peaks of precursor ions. Thus, although their product ions could be acquired, their precursor ions are absent. Here, we present a new strategy, chromatographic retention behavior-SWATH (CRB-SWATH), that could unbiasedly capture poor-quality peaks and provide high resolutions of multiplexed mass spectroscopy (MS/MS) spectra in SWATH datasets. CRB-SWATH monitors CRBs of SWATH-MS signals under a series of altered elution gradients. As signals of compounds differ from noise by showing CRBs, both the precursor and fragment ions are captured, while ignoring their peak qualities. Moreover, CRB-SWATH offers good chances to resolve highly multiplexed MS/MS spectra in SWATH datasets because precursor ions coeluted in a single elution gradient often present different CRBs. In the untargeted metabolic analysis of Hela cell extracts, CRB-SWATH showed the advantage in exclusively capturing 2645 ions of poor-quality peaks (i.e., tiny peaks, discontinuous ion traces, tailing peaks, zigzag peaks, etc.), accounting for 34.4% of all the untargeted precursor ions extracted. Therein, it is noteworthy that among 2116 negative ions detected in hydrophilic interaction liquid chromatography (HILIC) mode, 1284 poor-quality ion peaks (>60%) were exclusively captured by CRB-SWATH. As CRB-SWATH automatically captures a large sum of true ion peaks of poor qualities, extracts MS/MS spectra of high purities, and provides chromatographic retention behaviors of untargeted metabolites for identification and classification, it could be a useful metabolomics tool for understanding biological phenomena better.

Initiated by the specific binding between D‐glucose and biological receptors, the human body has a delicate metabolic system to regulate blood D‐glucose levels, but failing to release insulin would induce hyperglycemia or type I diabetes. While insulin delivery is an effective form of hyperglycemia therapy, the self‐regulated triggering of insulin release for on‐demand supplementation remains inadequate. Here, a biomimetic glucose trigger‐insulin release system, that is, a bidentate β‐cyclodextrin‐based hydrogel with preloaded insulin is presented; the dual self‐regulated system shows a specific D‐glucose response to realize accurate monitoring and simultaneous on‐demand trigger insulin release. The specific binding between D‐glucose and the bidentate β‐cyclodextrin induces the release of protons, causing macroscopic swelling of the hydrogel, subsequently triggering the on‐demand and long‐term supplementation of insulin. On the contrary, isomers of D‐glucose, such as D‐fructose and D‐galactose, cause shrinking of the hydrogel, and retard insulin release. In‐vivo studies in type I diabetic mice model ascertain that although the bidentate β‐CD hydrogel is preloaded with short‐activity insulin, it exerts long‐activity control of blood glucose level over 12 h.

Scope: Hyperglycemia‐induced cardiac fibrosis is one of the main causes of diabetic cardiomyopathy (DM). Chlorogenic acid (CGA) found in many foods has excellent hypoglycemic effectiveness, but it is not known whether CGA can improve DM by inhibiting cardiac fibrosis caused by hyperglycemia.Methods and Results: Type I diabetic mice are induced by streptozotocin, and after treatment with CGA for 12 weeks, cardiac functions and fibrosis are determined. CGA significantly attenuates hyperglycemia‐induced cardiac fibrosis and improves cardiac functions. The mechanism of CGA on fibrotic inhibition is further studied by immunofluorescence, western blot and RNA interference technology in vivo and in vitro. The results show CGA exerted its anti‐fibrotic effects through activating the cyclic GMP/protein kinase G pathway (cGMP/PKG) to block hyperglycemia‐induced nuclear translocation of p‐Smad2/3, and then inhibiting pro‐fibrotic gene expression in cardiac fibroblasts without depending on its hypoglycemic function. Moreover, the data also revealed that CGA increased cGMP level and activated PKG in cardiac fibroblasts by enhancing endothelial nitric oxide synthase (eNOS) activity and NO production.Conclusion: Besides lowering blood glucose, CGA also has an independent ability to inhibit cardiac fibrosis. Therefore, long‐term consumption of foods rich in CGA for diabetic patients will have great benefits to improve diabetic cardiomyopathy.