Prdx6-induced inhibition of ferroptosis in epithelial cells contributes to liquiritin-exerted alleviation of colitis.

Inhibition of ferroptosis in intestinal epithelial cells ameliorates clinical symptoms and improves endoscopic presentations in inflammatory bowel disease (IBD). Licorice is used worldwide in food and medicine fields. Liquiritin, a flavonoid component in licorice, is an effective substance used as an anti-inflammatory, antioxidant food that has been shown to improve chemically induced colitis. Herein we evaluated the therapeutic effects of liquiritin on colitis and determined whether liquiritin could affect colitis by modulating ferroptosis in epithelial cells. A colitis model was induced in mice by oral administration with 2.5% DSS dissolved in drinking water. The results showed that liquiritin significantly alleviated symptoms, suppressed intestinal inflammation and restored the epithelial barrier function in the colitis mouse model. Liquiritin supplementation upregulated colonic ferritin expression, increased the storage of cellular iron, reduced the cellular iron level and further inhibited ferroptosis in epithelial cells from the colitis model. Pharmacological stimulation of ferroptosis largely blocked liquiritin-induced alleviation of colitis. Peroxiredoxin-6 (Prdx6) expression was significantly decreased in the DSS group, which was reversed by liquiritin treatment. Genetic or pharmacological silencing of Prdx6 largely reversed liquiritin-induced modulation of the ferritin/iron level and ferroptosis in epithelial cells. Molecular docking results showed that liquiritin could bind to Prdx6 through the hydrogen bond interaction with amino acid residues Thr208, Val206 and Pro203. In conclusion, liquiritin treatment largely alleviated DSS induced colitis by inhibiting ferroptosis in epithelial cells. Liquiritin negatively regulated ferroptosis in epithelial cells in colitis by activating Prdx6, increasing the expression of ferritin and subsequently reducing the cellular iron level.

Low-temperature photothermal irradiation triggers alkyl radicals burst for potentiating cancer immunotherapy.

Although low-temperature photothermal therapy (PTT) can sensitize tumors to immune checkpoint inhibition, its efficacy is still restricted in the deep and internal tumors without enough oxygen and lymphocytic infiltration. Non-oxygen-dependent alkyl radicals have been demonstrated to synergistically enhance PTT through up-regulating lipid peroxidation and reactive oxygen species (ROS). Herein, an innovative strategy based on alkyl radicals to augment immunogenetic cell death (ICD) caused by mild PTT was proposed to improve poor efficacy of immunotherapy, which composed of a photothermal material of Chinse ink, an azo-initiator of 2,2-azobis[2-(2-imidazoline-2-acyl)propane]dihydrochloride (AIPH) and a PD-L1 inhibitor of HY19991 (HY). Upon near-infrared-II laser irradiation, low-temperature (<45℃) stimulation induced a high expression of immune checkpoint receptor (PD-L1) in tumors and triggered a large amount alkyl radicals generated by AIPH. Significantly, the alkyl radicals augmented the ICD and increased the recruitment of tumor-infiltrating lymphocytes against tumors after transformation of the immunologically cold tumor microenvironment into hot by mild PTT. The released HY further enhanced the immunotherapy effect by blocking the binding of activated T lymphocytes and PD-L1. In vivo studies exhibited that the all-in-one hydrogel with synergistic mechanisms had an extraordinary ability to reverse the immunosuppressive microenvironment, stimulate innate and adaptive immune responses to eliminate tumors and prevent metastasis.

Paeoniflorin Alleviates Abnormalities in Rats with Functional Dyspepsia by Stimulating the Release of Acetylcholine.

INTRODUCTION: Paeoniflorin is a main active component in traditional Chinese medicine. Paeoniae alba radix is widely used as a spasmolytic and pain-relieving agent for abdominal spasmodic pain. Functional dyspepsia (FD) is characterized by pain or burning in the epigastrium, fullness, bloating and nausea. However, limited information is available about the effect of paeoniflorin on FD. MATERIALS AND METHODS: In this study, iodoacetamide or clonidine-induced FD rat models were established to investigate the impacts of paeoniflorin on FD induced by different pathophysiologic disturbances. RESULTS: We found the therapeutic effect of paeoniflorin through assessing the gastric emptying, gastric accommodation and visceral hypersensitivity. This function of paeoniflorin was related to the release of acetylcholine (ACh), which was accompanied by reduced acetylcholinesterase (AchE) activity in stomach and hypothalamus. Paeoniflorin administration inhibited the cyclo-oxygenase-2 (COX-2) expression and increased the level of ghrelin in the stomach. Besides, the levels of occludin and ZO-1 were elevated in the duodenum from paeoniflorin-treated rats, suggesting the impaired duodenal barrier was ameliorated. DISCUSSION: These results indicate that paeoniflorin possesses the ability to alleviate functional dyspepsia.

Synergistic chemo-photothermal therapy of tumor by hollow carbon nanospheres.

Combined use of different therapies is conducive to improve the effectiveness of cancer therapy. The chemo-photothermal therapy is commonly used in one nanocarrier to provide an excellent synergistic effect for cancer therapy over photothermal therapy (PTT) or chemotherapy alone. In this study, biocompatible and monodisperse hollow carbon nanospheres (HCNs) were developed as a multifunctional platform for the delivery of paclitaxel (PTX) and PTT of cancer simultaneously. The mesoporous HCNs have large pore volume and proper channels for loading and release of PTX. Upon near-infrared (NIR) laser illumination, the photothermal mediator of HCNs could effectively convert absorbed light into heat, which triggered rapid release of chemotherapeutic drug from HCNs through dissociating the interactions between PTX and HCNs by heat energy. A large number of tumor cells were significantly destroyed when hct116 cells treated with PTX@HCNs were irradiated, which was mainly attribute to the synergistic result of HCNs-mediated photothermal damage and cytotoxicity of light-triggered PTX release.

Enhanced photothermal therapy of biomimetic polypyrrole nanoparticles through improving blood flow perfusion.

In this study, we reported a strategy to improve delivery efficiency of a long-circulation biomimetic photothermal nanoagent for enhanced photothermal therapy through selectively dilating tumor vasculature. By using a simply nanocoating technology, a biomimetic layer of natural red blood cell (RBC) membranes was camouflaged on the surface of photothermal polypyrrole nanoparticles (PPy@RBC NPs). The erythrocyte-mimicking PPy NPs inherited the immune evasion ability from natural RBC resulting in superior prolonged blood retention time. Additionally, excellent photothermal and photoacoustic imaging functionalities were all retained attributing to PPy NPs cores. To further improve the photothermal outcome, the endothelin A (ETA) receptor antagonist BQ123 was jointly employed to regulate tumor microenvironment. The BQ123 could induce tumor vascular relaxation and increase blood flow perfusion through modulating an ET-1/ETA transduction pathway and blocking the ETA receptor, whereas the vessel perfusion of normal tissues was not altered. Through our well-designed tactic, the concentration of biomimetic PPy NPs in tumor site was significantly improved when administered systematically. The study documented that the antitumor efficiency of biomimetic PPy NPs combined with specific antagonist BQ123 was particularly prominent and was superior to biomimetic PPy NPs (P < 0.05) and PEGylated PPy NPs with BQ123 (P < 0.01), showing that the greatly enhanced photothermal treatment could be achieved with low-dose administration of photothermal agents. Our findings would provide a promising procedure for other similar enhanced photothermal treatment by blocking ETA receptor to dramatically increase the delivery of biomimetic photothermal nanomaterials.

Effective cytotoxic activity of OSW-1 on colon cancer by inducing apoptosis in vitro and in vivo.

As a natural compound, Ornithogalum caudatum Ait is primarily used as an anti-inflammatory and antitumor agent in Chinese folk medicine. In 1992, OSW-1 was isolated from this compound, which is a new member of cholestane saponin family. In numerous recent studies, OSW-1 has been shown to have powerful cytotoxic anticancer effects against various malignant cells. However, the therapeutic efficacy of OSW-1 on colon cancer and the underlying mechanism are not understood. To explore the mechanism underlying OSW-1 in antitumor therapy, a therapeutic function analysis of OSW-1 on colon cancer was performed in vitro and in vivo. It was shown that with low toxicity on normal colonic cells, OSW-1 suppresses colon cancer cells in vitro and this inhibition was via the intrinsic apoptotic pathway, which increased cellular calcium, changed mitochondrial membrane potential, disrupted mitochondrial morphology, and led to the release of cytochrome c and the activation of caspase-3. Furthermore, in a nude mouse model, OSW-1 had a powerful effect on suppressing colon tumor proliferation without significant side effects through the apoptosis pathway. Taken together, these results demonstrate that OSW-1 is a potential drug for colon cancer treatment.

Gut microbial diversity analysis using Illumina sequencing for functional dyspepsia with liver depression-spleen deficiency syndrome and the interventional Xiaoyaosan in a rat model.

AIM: To investigate gut microbial diversity and the interventional effect of Xiaoyaosan (XYS) in a rat model of functional dyspepsia (FD) with liver depression-spleen deficiency syndrome. METHODS: The FD with liver depression-spleen deficiency syndrome rat model was established through classic chronic mild unpredictable stimulation every day. XYS group rats received XYS 1 h before the stimulation. The models were assessed by parameters including state of the rat, weight, sucrose test result and open-field test result. After 3 wk, the stools of rats were collected and genomic DNA was extracted. PCR products of the V4 region of 16S rDNA were sequenced using a barcoded Illumina paired-end sequencing technique. The primary composition of the microbiome in the stool samples was determined and analyzed by cluster analysis. RESULTS: Rat models were successfully established, per data from rat state, weight and open-field test. The microbiomes contained 20 phyla from all samples. Firmicutes, Bacteroidetes, Proteobacteria, Cyanobacteria and Tenericutes were the most abundant taxonomic groups. The relative abundance of Firmicutes, Proteobacteria and Cyanobacteria in the model group was higher than that in the normal group. On the contrary, the relative abundance of Bacteroidetes in the model group was lower than that in the normal group. Upon XYS treatment, the relative abundance of all dysregulated phyla was restored to levels similar to those observed in the normal group. Abundance clustering heat map of phyla corroborated the taxonomic distribution. CONCLUSION: The microbiome relative abundance of FD rats with liver depression-spleen deficiency syndrome was significantly different from the normal cohort. XYS intervention may effectively adjust the gut dysbacteriosis in FD.

CNP signal pathway up-regulated in rectum of depressed rats and the interventional effect of Xiaoyaosan.

AIM: To investigate the distribution and expression of C-type natriuretic peptide (CNP)/natriuretic peptide receptor B (NPR-B) in the rectum of a rodent depression model and the interventional effect of Xiaoyaosan (XYS). METHODS: Male rats (n = 45) of clean grade (200 ± 20 g) were divided into five groups after one week of adaptive feeding: primary control, depression model, low dose XYS, middle dose XYS, and high dose XYS. The animal experiment continued for 3 wk. Primary controls were fed normally ad libitum. The rats of all other groups were raised in solitary and exposed to classic chronic mild unpredictable stimulation each day. XYS groups were perfused intragastrically with low dose, middle dose, and high dose XYS one hour before stimulation. Primary control and depression model groups were perfused intragastrically with normal saline under similar conditions as the XYS groups. Three weeks later, all rats were sacrificed, and the expression levels of CNP and NPR-B in rectum tissues were analyzed by immunohistochemistry, real-time polymerase chain reaction, and Western blotting. RESULTS: CNP and NPR-B were both expressed in the rectum tissues of all rats. However, the expression levels of CNP and NPR-B at both gene and protein levels in the depression model group were significantly higher when compared to the primary control group (n = 9; P < 0.01). XYS intervention markedly inhibited the expression levels of CNP and NPR-B in depressed rats. The expression levels of CNP and NPR-B in the high dose XYS group did not significantly differ from the expression levels in the primary control group. Additionally, the high and middle dose XYS groups (but not the low dose group) significantly exhibited lower CNP and NPR-B expression levels in the rectum tissues of the respectively treated rats compared to the untreated depression model cohort (n = 9; P < 0.01). CONCLUSION: The CNP/NPR-B pathway is upregulated in the rectum of depressed rats and may be one mechanism for depression-associated digestive disorders. XYS antagonizes this pathway at least partially.

Morphological changes in network of enteric nerve-interstitial cells of Cajal-smooth muscle cells in rats with multiple organ dysfunction syndrome and therapeutic effects of Dachengqi decoction (大承气汤).

OBJECTIVE: To observe the effects of Dachengqi Decoction (大承气汤, DCQD) on morphological changes in the network of enteric nerve-interstitial cells of Cajal (ICCs)-smooth muscle cells (SMC) of enteric deep muscular plexuses (DMP) in the rats with multiple organ dysfunction syndrome (MODS). METHODS: One hundred Wistar rats of both sexes weighing 200 to 250 g were randomly divided into the control group, MODS group, and DCQD group. The morphologic changes of enteric nerve-ICC-SMC network in the DMP of intestine was observed using c-Kit and vesicular acetylcholine transporter/neuronal nitric oxide synthase immunohistochemical double-staining with whole-mount preparation technique, confocal laser scanning microscopy, and electron microscopy. RESULTS: Compared with the control group, the distribution and densities of cholinergic/nitrergic nerves and ICC in the DMP (ICC-DMP) of intestine in the MODS group were significantly decreased (P<0.01), and the network of cholinergic nerve-ICC-SMC was disrupted; and the ultrastructural features of ICC-DMP, enteric nerve, and SMC were severely damaged. After treatment with DCQD, the damage in the network of enteric nerve-ICC-SMC was significantly recovered. Compared with the MODS group, the distribution and densities of cholinergic/nitrergic nerves and ICC-DMP in the DCQD group were significantly increased (P<0.01); and the ultrastructural features of ICC-DMP, enteric nerve, smooth muscle cells were significantly recovered. CONCLUSIONS: DCQD can improve the gastrointestinal motility in MODS. The mechanism may be related to the effect of repairing the damages in the network of enteric nerve-ICC-SMC.