Impact of Sensitization and Inflammation on the Interaction of Mast Cells With the Intestinal Epithelium in Rats

Effect and mechanism of Magnolia officinalis in colorectal cancer: multi-component-multi-target approach

ETHNOPHARMACOLOGICAL RELEVANCE

Colorectal cancer (CRC) is a prevalent malignant tumor of the digestive tract. Traditional Chinese medicine (TCM) has a long history of treating CRC, with advantages such as effectiveness, multi-target, multi-pathway, and minimal side effects. TCM Magnolia officinalis (M. officinalis) refers to the dried bark, root bark, and branch bark of either Magnolia officinalis Rehd.et Wils. or Magnolia officinalis Rehd.et Wils. var. biloba Rehd.et Wils.. It is commonly utilized to alleviate the side effects of chemotherapy for CRC, owing to its anti-inflammatory and anti-tumor properties. However, current research primarily focuses on the individual components and does not take into consideration the characteristics of multi-component-multi-target action.

AIM OF THE STUDY

Our aim is to study the new action characteristics of M. officinalis in the treatment of CRC.

MATERIALS AND METHODS

Utilizing network pharmacology to identify potential active ingredients, key targets, and main signaling pathways of M. officinalis for the treatment of CRC. The binding effect was further validated through molecular docking analysis. Furthermore, the aforementioned components were identified using liquid chromatography-mass spectrometry (LC-MS), and the cleavage pathways of the main components were analyzed. Subsequently, both in vitro and in vivo experiments were carried out to investigate the anti-CRC effect of the active ingredients of M. officinalis and its potential mechanism.

RESULTS

Network pharmacology and Molecular docking identified 5 main active ingredients and 6 core targets of M. officinalis for the treatment of CRC. Then, LC-MS identified the active components of M. officinalis. At the same time, both in vitro and in vivo experiments have confirmed the ability of Eucalyptol (Euc) and Obovatol (Obo)to inhibit inflammation and tumor cell proliferation. The possible mechanism involved is that Euc and Obo counteract CRC by inhibiting the over-activation of NF-κBp65/JAK and Bcl-2/Caspase signaling pathways, respectively. They also play a role in the anti-CRC effect of M. officinalis.

CONCLUSION

Magnolol (MAG), Honokiol (HK), Euc, Obo, and Neohesperidin (NHP) in M. officinalis may be the pharmacological substance basis for its anti-cancer effect on CRC. The treatment of CRC with M. officinalis is characterized by its multi-component, multi-target, and multi-pathway approach. These findings provide a theoretical basis for further inspiring the clinical application of M. officinalis and the development of efficacy targets.

Tranilast Treatment Prevents Chronic Radiation-Induced Colitis in Rats by Inhibiting Mast Cell Infiltration

INTRODUCTION

Mast cells are the principal cells involved in acute and chronic colitis due to radiation, known as radiation-induced colitis (RIC). In this study, we investigated whether pretreatment with tranilast, a mast cell inhibitor, could alleviate chronic RIC.

METHODS

A total of 23 Sprague-Dawley rats were randomly divided into three groups: control group (n = 5), radiation group (RG, n = 9), and tranilast-pretreated radiation group (TG, n = 9). The rats in the RG and the TG were irradiated in the pelvic area (1.5 cm from the anus) with a single dose of 20 Gy under general anesthesia. Tranilast (100 mg/kg) was administered intraperitoneally to the rats of the TG for 10 days, starting from the day of pelvic radiation. Ten weeks after radiation, the rats were euthanized. Rectal tissue samples were histologically evaluated for the total inflammation score (TIS) and mast cell count. The expression of MUC2, MUC5AC, and matrix metalloproteinase-9 (MMP-9) was also assessed immunohistochemically.

RESULTS

Both the TIS and specific components of TIS such as epithelial atypia, vascular sclerosis, and colitis cystica profunda (CCP) were significantly higher in the RG than in the TG (p = 0.02, 0.038, 0.025, and 0.01, respectively). Thein number of infiltrating mast cells was significantly higher in the RG than in the TG (median [range]: 20 [3-54] versus 6 [3-25], respectively; p = 0.034). Quantitatively, the number of MMP-9-positive cells was significantly higher in the RG (23.67 ± 19.00) than in the TG (10.25 ± 8.45) (mean ± standard deviation; p < 0.05). TIS and MMP-9 exhibited a strong association (correlation coefficient r = 0.56, p < 0.05). Immunohistochemically, the mucin-lake of CCP showed no staining for MUC5AC but was stained positive for MUC2.

CONCLUSION

Tranilast pretreatment of chronic RIC showed an anti-inflammatory effect associated with the reduction of mast cell infiltration and MMP-9 expression.

Time-dependent effects of tumor necrosis factor α on Ca2+-dependent secretion in murine small intestinal organoids

Background

Intestinal organoids are stem cell-derived, 3D "mini-guts" with similar functions as the native intestinal epithelium such as electrolyte transport or establishment of an epithelial barrier. During intestinal inflammation, epithelial functions are dysregulated by proinflammatory cytokines like tumor necrosis factor α (TNFα) and other messengers from the immune system resulting in a loss of electrolytes and water due to an impaired epithelial barrier and higher net secretion.

Methods

A murine small intestinal organoid model was established to study (long-term) effects of TNFα on the intestinal epithelium in vitro using live imaging, immunohistochemical staining and qPCR.

Results

TNFα induced apoptosis in intestinal organoids as indicated by an increased number of cells with immunoreactivity for cleaved caspase 3. Furthermore, TNFα exposure led to swelling of the organoids which was inhibited by bumetanide and was concomitant with an upregulation of the bumetanide-sensitive Na+-K+-2Cl- symporter 1 (NKCC1) as shown by qPCR. Fura-2 imaging experiments revealed time-dependent changes in Ca2+ signaling consisting of a rise in the basal cytosolic Ca2+ concentration at day 1 and an increase of the carbachol-induced Ca2+ response after 3 days TNFα exposure. This was prevented by preincubation with La3+, an inhibitor of non-selective cation channels, or by using a Ca2+-free buffer indicating an enhancement of the Ca2+ influx from the extracellular side by the cytokine. No significant changes in cDNA levels of epithelial barrier proteins could be observed in the presence of TNFα.

Conclusion

Intestinal organoids are a useful tool to study the mechanism underlying the TNFα-induced secretion on enterocytes such as the regulation of NKCC1 expression or the modulation of cellular Ca2+ signaling.

Proteinase-activated receptors regulate intestinal functions in a segment-dependent manner in rats

Proteinases released e.g. during inflammatory or allergic responses affect gastrointestinal functions via proteinase-activated receptors such as PAR1 and PAR2. As the gastrointestinal tract exerts pronounced gradients along its longitudinal axis, the present study focuses on the effect of PAR1 and PAR2 agonists on electrogenic ion transport (measured as short-circuit current; I_sc), tissue conductance (G_t) and contractility of the longitudinal muscle layer of rats. In Ussing chamber experiments, the PAR1 agonist TFLLR-NH₂, which mimics the tethered ligand liberated after cleavage of the receptor, evoked only a modest increase in I_sc (<0.5 μEq·h^-1·cm^-2) in small intestine, but a strong increase (3-4 μEq·h^-1·cm^-2) in colon. Pretreatment with tetrodotoxin reduced the response of the colonic segments to the level of the small intestine. Thrombin, the natural activator of PAR1, was much less effective suggesting biased activation by this peptidase. A similar gradient along the longitudinal axis of the intestine was observed with trypsin, the endogenous activator of PAR2. Divergent actions of PAR1 activation by enzymatic cleavage or a mimetic peptide were also observed when recording isometric contractions of longitudinal muscle. For example, in the jejunum TFLLR-NH₂ concentration-dependently induced a contractile response, whereas thrombin showed only inconsistent effects. The PAR2 activator AC264613 induced a concentration-dependent decrease in muscle tone combined with an inhibition of phasic spontaneous contractions. PCR experiments and immunohistochemical stainings confirmed the expression of PAR1 and PAR2. The data implies that PAR1 and PAR2 functions vary depending on the intestinal segment.

Tanshinone IIA attenuates AOM/DSS-induced colorectal tumorigenesis in mice via inhibition of intestinal inflammation

CONTEXT

Tanshinone IIA is a natural extract derived from a Chinese medicinal herb with multiple bioactivities; however, whether and how tanshinone IIA protects against colorectal cancer (CRC) are uncertain.

OBJECTIVE

We investigated the potential beneficial effects of tanshinone IIA in a colitis-associated colorectal tumorigenesis mouse model and its underlying mechanisms.

MATERIALS AND METHODS

Male C57BL/6 mice were treated with azoxymethane (AOM) 10 mg/kg body weight and dextran sulphate sodium (2.5% DSS) to induce a colitis-associated cancer model. Tanshinone IIA (200 mg/kg body weight) was given to the mice intraperitoneally. After 12 weeks, all mice were sacrificed to measure tumour formation, intestinal permeability, neutrophil infiltration, and colonic inflammation. In addition, whether tanshinone IIA has inhibitory effects on neutrophil activation was determined through in vitro investigations.

RESULTS

We observed that tanshinone IIA significantly decreased tumour formation in AOM/DSS-treated mice compared to AOM/DSS-treated alone mice (0.266 ± 0.057 vs. 0.78 ± 0.153, p = 0.013). Tanshinone IIA also decreased intestinal permeability compared to that in AOM/DSS-treated alone mice (3.12 ± 0.369 vs. 5.06 ± 0.597, p = 0.034) and consequently reduced neutrophil infiltration of the colonic mucosa (53.25 ± 8.85 vs. 107.6 ± 13.09, p = 0.014) as well as intestinal inflammation in mice. Mechanistically, tanshinone IIA downregulated the NF-κB signalling pathway in the colonic tumours of AOM/DSS-treated mice. In vitro assays further validated that tanshinone IIA suppressed LPS-induced neutrophil activation.

CONCLUSION

These data suggest that tanshinone IIA alleviates colorectal tumorigenesis through inhibition of intestinal inflammation. Tanshinone IIA may have a therapeutic potential for CRC in clinical practice.

Screening of Prospective Plant Compounds as H1R and CL1R Inhibitors and Its Antiallergic Efficacy through Molecular Docking Approach

Allergens have the ability to enter the body and cause illness. Leukotriene is the widespread allergen which could stimulate mast cells to discharge histamine which causes allergy symptoms. An effective strategy for treating leukotriene-induced allergy is to find the inhibitors of leukotriene or histamine activity from phytochemicals. For this purpose, a library of 8,500 phytochemicals was generated using MOE software. The structures of histamine-1 receptor and cysteinyl leukotriene receptor-1 were predicted by the homology modeling method through the SWISS model. The phytochemicals were docked with predicted structures of histamine-1 and cysteinyl leukotriene receptor-1 in MOE software to determine the binding affinity of the phytochemicals against the targets. Moreover, chemoinformatics properties and ADMET of phytochemicals were assessed to find the drug likeness behavior of compounds. Compound ID 10054216 has the lowest $S$ -score value for H-1 receptor that is -18.9186 kcal/mol which is lower than the value of standard -15.167 kcal/mol. The other compounds 393471, 71448939, 10722577, and 442614 also showed good $S$ -score values than the standard. Moreover, compound ID 11843082 has the lowest $S$ -score value for CL1R that is -15.481 kcal/mol which is lower than the value of standard -12.453 kcal/mol. The other compounds 72284, 5282102, 66559251, and 102506430 also showed good $S$ -score values than the standard. In this research article, we performed molecular docking to find the best inhibitors against H1R and CL1R and their antiallergic efficacy. This in silico knowledge will be helpful in near future for the design of novel, safe, and less costing H-1 receptor and CL1R inhibitors with the aim to improve human life quality.

Interactions between rat submucosal neurons and mast cells are modified by cytokines and neurotransmitters

The role of mast cells during inflammatory bowel diseases (IBD) is discussed controversially. Whereas several studies report an increase in mast cell density during IBD, others found a decrease. Recently, we observed a reduced response to mast cell degranulation induced by antigen contact in a colitis model. As the effects of mast cell mediators on epithelial ion transport are mediated indirectly via stimulation of secretomotor neurons, we investigated in vitro whether proinflammatory cytokines change the response to mast cell degranulation. Tumor necrosis factor α (TNFα) and a mix of proinflammatory cytokines caused an increase of short-circuit current (I_sc) and tissue conductance in rat colon. Anion secretion induced by histamine was downregulated in the presence of interleukin-1β (IL-1β) and the cytokine mix, whereas the response to the mast cell stimulator compound 48/80 was not changed significantly. In a coculture of rat submucosal ganglionic cells with a mast cell line (RBL-2H3), TNFα preincubation for 1 d increased the percentage of neurons responding to mast cell degranulation with an increase of the cytosolic Ca²⁺ concentration and enhanced the amplitude of this response. Consequently, the downregulation of epithelial secretion is compensated by an increased sensitivity of secretomotor neurons leading to a constant response of the epithelium to compound 48/80. Furthermore, enteric neurons can modify mast cell functions as nicotine inhibited the increase in cytosolic Ca²⁺ concentration of RBL-2H3 cells and the I_sc evoked by compound 48/80. Consequently, these in vitro models deliver new insights into cellular interactions in the gut wall under inflammatory conditions.