Recent Advances in Cell-Based In Vitro Models to Recreate Human Intestinal Inflammation

Per- and polyfluoroalkyl substances as potentiators of hepatotoxicity in an exposome framework: Current challenges of environmental toxicology

Chronic liver diseases, including metabolic dysfunction-associated steatosic liver disease (MASLD) and hepatocellular carcinoma (HCC), are on the rise, potentially due to daily exposure to complex mixtures of chemical compounds forming part of the exposome. Understanding the mechanisms involved in hepatotoxicity of these mixtures is essential to identify common molecular targets that may highlight potential interactions at the molecular level. We illustrated this issue with two families of environmental contaminants, per- and polyfluoroalkyl substances (PFAS) and heterocyclic aromatic amines (HAAs), both of which could be involved in the progression of chronic liver diseases, and whose toxicity may be potentiated by interactions at the level of xenobiotic metabolism. In the study of exposome effects on chronic liver disease, New Approach Methodologies (NAMs) including omics analyses and data from various in vitro, in vivo and in silico approaches, are crucial for improving predictivity of toxicological studies in humans while reducing animal experimentation. Additionally, the development of complex in vitro human liver cell models, such as organoids, is essential to avoid interspecies differences that minimize the risk for humans. All together, these approaches will contribute to construct Adverse Outcome Pathways (AOPs) and could be applied not only to PFAS mixtures but also to other chemical families, providing valuable insights into mixture hepatotoxicity prediction in the study of the exposome. A better understanding of toxicological mechanisms will clarify the role of environmental contaminant mixtures in the development of MASLD and HCC, supporting risk assessment for better treatment, monitoring and prevention strategies.

Chinese yam (Dioscorea) polysaccharide ameliorates ulcerative colitis in mice via modulating disorders of intestinal microecology and metabolism

Clinical research has demonstrated that non-starch polysaccharides from natural sources exhibit protective and therapeutic effects on ulcerative colitis (UC). In this study, a non-starch polysaccharide (CYP-A) with a molecular weight of 1.54 × 103 kDa was isolated from a speciality Chinese yam (Dioscorea) variety, the Ma yam, consisting mainly of mannose and glucose. The results indicated that CYP-A alleviated colitis symptoms induced by dextran sulfate sodium (DSS), repaired the mucus barrier, and protected the integrity of the intestinal mechanical barrier. Furthermore, CYP-A suppressed pro-inflammatory cytokine production, reduced oxidative stress, and modulated the biological barriers by facilitating the colonization of norank_f-_Muribaculaceae, Dubosella, Faecalibaculum and Enterorhabdus, while reducing Escherichia-Shigella and Bacteroides. Notably, CYP-A reshaped the metabolic pathways related to steroid hormone biosynthesis as well as phenylalanine, tyrosine, and histidine metabolism. These findings highlight the potential of CYP-A as a nutraceutical for targeting UC and improving gut health.

Squamous cell carcinoma of the small intestine: a case report and review of literature

Malignant tumors derived from the small intestine are rare, and most are adenocarcinomas. Primary squamous cell carcinoma of the small intestine is sporadic with a few cases reported in the literature. This study reports a case of a 56-year-old female who had a history of leakage of exudate for more than 40 years after an appendectomy. The patient presented with increasing leakage of exudate, abdominal pain, and fever this time, and was diagnosed with primary squamous cell carcinoma of the ileal after an intestinal resection and a fascial plasty. The patient declined to receive adjuvant chemotherapeutic treatment and died 9 months after the diagnosis of the tumor. Additionally, we reviewed 26 reported cases, summarized the clinical features and treatments, and discussed the potential pathogenesis and optional therapeutic strategies for primary squamous cell carcinoma of the small intestine.

Orally Bioavailable BRD4 BD1 Inhibitor ZL0516 Effectively Suppresses Colonic Inflammation in Animal Models of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), a chronic, progressive, and recurrent gastrointestinal inflammatory disorder, poses a significant threat to global health and exerts an adverse effect on the quality of life. Currently, there is a lack of effective therapies for IBD. Developing novel targeted therapies for IBD, particularly orally effective therapeutics, is a vital need for IBD patients. Herein, we first demonstrate that BRD4/NF-κB signaling is aberrantly activated in the colons of human IBD biopsy samples compared to that of normal healthy controls. ZL0516, a potent, selective, and orally bioavailable BRD4 BD1 inhibitor, significantly inhibits the TNFα- and LPS-induced expression of inflammatory cytokines in human colonic epithelial cells (HCECs) and peripheral blood mononuclear cells (PBMCs) with low cytotoxicity. Intriguingly, when administered in a preventive mode, ZL0516 significantly blocks dextran sulfate sodium (DSS)-induced murine colitis. When used in a therapeutic mode, ZL0516 effectively suppresses colonic inflammation in several IBD-relevant animal models: DSS-, oxazolone (OXA)-, and flagellin (Cbir1) T cell-induced chronic murine colitis models of IBD. ZL0516 suppresses IBD inflammatory responses in vitro and in vivo by blocking the activation of the BRD4/NF-κB signaling pathway. Also, we found that RVX208, a selective BRD4 BD2 inhibitor in Phase III clinical development, only displayed marginal effects in these IBD animal models. Collectively, our results demonstrate that specific BRD4 BD1 inhibition is a novel therapeutic strategy for IBD-associated colonic inflammation, and orally effective inhibitor ZL0516 is a promising candidate for the development of a novel therapeutic regimen against IBD.

Smart Polymeric 3D Microscaffolds Hosting Spheroids for Neuronal Research via Quantum Metrology

Toward the aim of reducing animal testing, innovative in vitro models are required. Here, this study proposes a novel smart polymeric microscaffold to establish an advanced 3D model of dopaminergic neurons. These scaffolds are fabricated with Ormocomp via Two-Photon Polymerization. The scaffolds are further enhanced by functionalization with fluorescent nanodiamonds (FNDs), which can serve as quantum nanosensors for both magnetic and temperature sensing. The material biocompatibility is tested using two different cell lines, SH-SY5Y and A431, with cell viability over 98%. A total of 69% of the FNDs are grafted on the structure compared to those that remained on the glass surface. Cells are tested with the scaffolds in several microenvironments, and the final assembly required for 3D quantum metrology experiments achieved 91% biocompatibility. Subsequently, embryoid bodies containing dopaminergic neurons, the cell type affected by Parkinson's disease (PD), are integrated with FND-functionalized scaffolds. This 3D model is successfully established, demonstrated by strong interactions between dopaminergic neurons and the scaffold, with the directional growth of neurites along the 3D scaffold. Ultimately, this study have developed a 3D platform that enables the readout of signaling in a model that holds great potential for future PD research.

Blueberry-derived exosome like nanovesicles carry RNA cargo into HIEC-6 cells and down-regulate LPS-induced inflammatory gene expression: A proof-of-concept study

Exosome-like nanovesicles (ELNs) of food origin have received great attention in the last decade, due to the hypothesis that they contain bioactive molecules. ELNs purified from edible species have been shown to be protective and are able to regulate intestinal homeostasis. Despite ELNs being potential rising stars in modern healthy diets and biomedical applications, further research is needed to address underlying knowledge gaps, especially related to the specific molecular mechanism through which they exert their action. Here, we investigate the cellular uptake of blueberry-derived ELNs (B-ELNs) using a human stabilized intestinal cell line (HIEC-6) and assess the ability of B-ELNs to modulate the expression of inflammatory genes in response to lipopolysaccharide (LPS). Our findings show that B-ELNs are internalized by HIEC-6 cells and transport labeled RNA cargo into them. Pretreatment with B-ELNs reduces LPS-induced ROS generation and cell viability loss, while modulating the expression of 28 inflammatory genes compared to control. Pathway analysis demonstrates their ability to suppress inflammatory responses triggered by LPS. In conclusion, our data indicate that B-ELNs are up taken by HIEC-6 cells and can modulate inflammatory responses after LPS stimulation, suggesting a therapeutic potential. This study demonstrates the role of B-ELNs in regulating crucial biological processes, like anti-inflammatory responses, which could support intestinal health.

Novel full-thickness biomimetic corneal model for studying pathogenesis and treatment of diabetic keratopathy

Diabetic keratopathy (DK), a significant complication of diabetes, often leads to corneal damage and vision impairment. Effective models are essential for studying DK pathogenesis and evaluating potential therapeutic interventions. This study developed a novel biomimetic full-thickness corneal model for the first time, incorporating corneal epithelial cells, stromal cells, endothelial cells, and nerves to simulate DK conditions in vitro. By exposing the model to a high-glucose (HG) environment, the pathological characteristics of DK, including nerve bundle disintegration, compromised barrier integrity, increased inflammation, and oxidative stress, were successfully replicated. Transcriptomic analysis revealed that HG downregulated genes associated with axon and synapse formation while upregulating immune response and oxidative stress pathways, with C-C Motif Chemokine Ligand 5 (CCL5) identified as a key hub gene in DK pathogenesis. The therapeutic effects of Lycium barbarum glycopeptide (LBGP) were evaluated using this model and validated in db/db diabetic mice. LBGP promoted nerve regeneration, alleviated inflammation and oxidative stress in both in vitro and in vivo models. Notably, LBGP suppressed the expression of CCL5, highlighting its potential mechanism of action. This study establishes a robust biomimetic platform for investigating DK and other corneal diseases, and identifies LBGP as a promising therapeutic candidate for DK. These findings provide valuable insights into corneal disease mechanisms and pave the way for future translational research and clinical applications.

Sea Anemone Kunitz Peptide HCIQ2c1 Reduces Histamine-, Lipopolysaccharide-, and Carrageenan-Induced Inflammation via the Suppression of Pro-Inflammatory Mediators

Inflammation is a physiological response of the immune system to infectious agents or tissue injury, which involves a cascade of vascular and cellular events and the activation of biochemical pathways depending on the type of harmful agent and the stimulus generated. The Kunitz peptide HCIQ2c1 of sea anemone Heteractis magnifica is a strong protease inhibitor and exhibits neuroprotective and analgesic activities. In this study, we investigated the anti-inflammatory potential of HCIQ2c1 in histamine- and lipopolysaccharide (LPS)-activated RAW 264.7 macrophages as well as in LPS-induced systemic inflammation and carrageenan-induced paw edema models in CD-1 mice. We found that 10 μM HCIQ2c1 dramatically decreases histamine-induced intracellular Ca2+ release and LPS-induced reactive oxygen species (ROS) production in RAW 264.7 macrophages. Moreover, HCIQ2c1 significantly inhibited the production of LPS-induced tumor necrosis factor α (TNF-α), inducible NO-synthase (iNOS), and 5-lipoxygenase (5-LO) but slightly influenced the IL-1β and cyclooxygenase-2 (COX-2) expression level in macrophages. Furthermore, intravenous administration by HCIQ2c1 at 0.1 mg/kg dose reduced LPS-induced TNF-α, IL-1β, COX-2, and iNOS gene expression in CD-1 mice. The subplantar administration of HCIQ2c1 at 0.1 mg/kg dose to mice significantly reduced carrageenan-induced paw edema by a factor of two, which is comparable to the effect of diclofenac at 1 mg/kg dose. Thus, peptide HCIQ2c1 has a strong anti-inflammatory potential by the attenuation of systemic and local inflammatory effects through the inhibition of intracellular Ca2+ release, the production of ROS and pro-inflammatory cytokines, and enzymes involved in arachidonic acid metabolism.

Curcumin attenuates ulcerative colitis via regulation of Sphingosine kinases 1/NF-κB signaling pathway

Curcumin, a compound from Curcuma longa L., has significant anti-inflammatory properties. However, the mechanisms underlying its anti-inflammatory activity in dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) remain inadequately understood. This study aimed to further elucidate the molecular mechanisms of curcumin DSS-induced UC mice. Our data showed that curcumin alleviated DSS-induced colitis by reducing intestinal damage and inflammation, increasing goblet cells in colon tissues. Enzyme-linked immunosorbent assay revealed that curcumin reduced the expression of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1β, and interleukin-8) in serum and myeloperoxidase in colon tissues. A comprehensive analysis integrating network pharmacology and RNA sequencing (RNA-seq) revealed significant enrichment of the nuclear factor kappa B (NF-κB) signaling pathways. Notably, RNA-seq analysis demonstrated that curcumin significantly downregulated the mRNA expression of sphingosine kinase 1 (SphK1). Furthermore, molecular docking analysis showed that curcumin can bind to SphK1 and NF-κB. Additionally, curcumin was found to inhibit the activation of the SphK1/NF-κB signaling pathway in DSS-induced UC colon tissue. This study addresses pharmacologic and mechanistic perspectives of curcumin that ameliorates DSS-induced UC and inflammatory response.

A mitochondria-targeted nitric oxide probe with large Stokes shift for real-time imaging and evaluation of inflammatory bowel disease in situ

BACKGROUND

Inflammatory bowel disease (IBD) is a prevalent inflammatory disorder, and the abnormal expression of nitric oxide (NO) produced by biocatalysis of iNOS enzyme in mitochondria is directly associated with the occurrence and progression of IBD. Activatable fluorescent probes offer promising tools for early diagnosis of IBD, however, inadequate biodistribution and limited targeting properties of these probes in vivo severely impede accurate diagnosis of IBD and real-time evaluation of inflammatory levels in situ. Therefore, it is necessary to design a highly efficient fluorescent probe towards NO to overcome inadequate biodistribution and achieve accurate diagnosis and evaluation of IBD in situ.

RESULTS

We designed a highly efficient mitochondria-targeted "turn-on" NIR fluorescent probe Cy-OMe which has excellent targeting properties and imaging ability. The response mechanism is probe Cy-OMe rapidly undergoes N-nitrosation reaction resulting in "turn-on" NIR fluorescence signal when exposed to NO. Cy-OMe exhibits high sensitivity and specificity in detecting NO content in vitro, owing to its large Stokes shift. Furthermore, the probe Cy-OMe not only efficiently targets mitochondria but also enables precise assessment of fluctuations in endogenous NO concertation across various cell types. Importantly, by virtue of large Stokes shift and excellent mitochondrial targeting ability, Cy-OMe has the capability to specifically evaluate dynamic fluctuations of NO in lipopolysaccharide (LPS)-stimulated IBD mouse models in situ and Cy-OMe was achieved high-contrast imaging and precision diagnosis of intestinal inflammation diseases.

SIGNIFICANCE

Cy-OMe can accurately assess fluctuations in NO levels and show high signal fidelity in the diseased intestine region, which has prospects in the non-invasive diagnosis of intestinal inflammation in vivo. At the same time, it is expected to serve as a potential diagnose platform for investigating the physiological processes underlying NO-related inflammatory diseases and promoting understanding of the pathological functions of NO across diverse inflammatory diseases.

Simulator of the Human Intestinal Microbial Ecosystem (SHIME®): Current Developments, Applications, and Future Prospects

The human gastrointestinal microbiota plays a vital role in maintaining host health and preventing diseases, prompting the creation of simulators to replicate this intricate system. The Simulator of the Human Intestinal Microbial Ecosystem (SHIME®), a multicompartment dynamic simulator, has emerged as a pivotal in vitro model for studying the interactions and interferences within the human gut microbiota. The continuous and real-time monitoring hallmarks, along with the programmatically flexible setup, bestow SHIME® with the ability to mimic the entire human intestinal ecosystem with high dynamics and stability, allowing the evaluation of various treatments on the bowel microbiota in a controlled environment. This review outlines recent developments in SHIME® systems, including the M-SHIME®, Twin-SHIME®, Triple-SHIME®, and Toddle SHIME® models, highlighting their applications in the fields of food and nutritional science, drug development, gut health research, and traditional Chinese medicine. Additionally, the prospect of SHIME® integrating with other advanced technologies is also discussed. The findings underscore the versatility of SHIME® technology, demonstrating its significant contributions to current gut ecosystem research and its potential for future innovation in microbiome-related fields.

Intracellularly Gelated Macrophages Loaded with Probiotics for Therapy of Colitis

Probiotics therapy has garnered significant attention in the treatment of inflammatory bowel disease (IBD). However, a large number of oral administrated probiotics are inactivated after passing through the gastric acid environment, and their ability to colonize in the intestine is also weak. Herein, this study develops a novel probiotics formulation (GM-EcN) by incorporating Escherichia coli Nissle 1917 (EcN) into intracellularly gelated macrophages (GM). Intracellular hydrogel is designed to load and prevent EcN from digestion in gastric juice, and GM acts as a macrophage-like carrier to carry the attached probiotics to colonize in the inflammatory intestine. In addition, hydrogel serves as an ideal cytoskeletal structure to maintain the intact cell morphology and membrane structure of GM, comparable to source macrophages. Due to the receptor-ligand interaction, inflammation-related membrane proteins enable GM as a cell sponge to sequestrate and neutralize multiple inflammatory cytokines. In vivo treatment demonstrates that GM-EcN efficiently alleviates IBD symptoms and enhances gut microbiota recovery.

An Easy-to-Use Arrayed Brain-Heart Chip

Multi-organ chips are effective at emulating human tissue and organ functions and at replicating the interactions among tissues and organs. An arrayed brain-heart chip was introduced whose configuration comprises open culture chambers and closed biomimetic vascular channels distributed in a horizontal pattern, separated from each other by an endothelial barrier based on fibrin matrix. A 300 μm-high and 13.2 mm-long endothelial barrier surrounded each organoid culture chamber, thereby satisfying the material transport requirements. Numerical simulations were used to analyze the construction process of fibrin barriers in order to optimize the structural design and experimental manipulation, which exhibited a high degree of correlation with experiment results. In each interconnective unit, a cerebral organoid, a cardiac organoid, and endothelial cells were co-cultured stably for a minimum of one week. The permeability of the endothelial barrier and recirculating perfusion enabled cross talk between cerebral organoids and cardiac organoids, as well as between organoids and endothelial cells. This was corroborated by the presence of cardiac troponin I (cTnI) in the cerebral organoid culture chamber and the observation of cerebral organoid and endothelial cells invading the fibrin matrix after one week of co-culture. The arrayed chip was simple to manipulate, clearly visible under a microscope, and compatible with automated pipetting devices, and therefore had significant potential for application.

Modulation of Photosensitizing Responses in Cell Culture Environments by Different Medium Components

Many cell culture experiments are performed under light to evaluate the photodynamic or photosensitizing efficacy of various agents. In this study, the modulation of photosensitizing responses and phototoxicity under cell culture conditions by different medium components was investigated. The significant levels of reactive oxygen species (ROS) generated from DMEM, RPMI 1640, and MEM were observed under the irradiation of fluorescent light (FL) and white and blue LEDs, indicating that these media have their own photosensitizing properties; DMEM showed the most potent property. Phenol red-free DMEM (Pf-D) exhibited a stronger photosensitizing property than normal DMEM by 1.31 and 1.25 times under FL and blue LEDs, respectively; phenol red and riboflavin-free DMEM (PRbf-D) did not show any photosensitizing properties. The inhibitory effect on light transmission was more pronounced in DMEM than in RPMI, and the interference effect on green LED light was greatest at 57.8 and 27.4%, respectively; the effect disappeared in Pf-D. The media containing riboflavin induced strong phototoxicity in HaCaT keratinocytes by generating H2O2 under light irradiation, which was quenched by sodium pyruvate in the media. The presence of serum in the media was also reduced the phototoxicity; H2O2 levels in the media decreased serum content dependently. The phototoxicity of erythrosine B and protoporphyrin IX under FL was more sensitively pronounced in PRbf-D than in DMEM. The present results indicate that several medium components, including riboflavin, phenol red, sodium pyruvate, and serum, could modulate photosensitizing responses in a cell culture system by inducing photosensitizing activation and by interfering with irradiation efficacy and ROS generation.

Mini-colons predict drug toxicity in vitro

Mitrofanova et al.1 engineer a human colonic in vitro model capable of producing an intestinal mucus barrier, with potential applications for predicting drug-induced gastrointestinal toxicity. This improved system paves the way for more accurate and efficient drug development processes.

Pasteurized form of a potential probiotic lactobacillus brevis IBRC-M10790 exerts anti-inflammatory effects on inflammatory bowel disease in vitro

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic, relapsing inflammatory disorder of the gastrointestinal system. So far, no treatment has been identified that can completely cure IBD. Lactobacillus brevis is hypothesized to be beneficial in preventing inflammation. This study aimed to evaluate the potential probiotic effects of live and pasteurized L. brevis IBRC-M10790 on the in vitro cell co-culture model of IBD.

METHODS

An in vitro intestinal model was established using a transwell co-culture system of Caco-2 intestinal epithelial cells and RAW264.7 macrophages. Inflammatory conditions were induced in RAW264.7 cells using lipopolysaccharide. The effects of live and pasteurized L. brevis IBRC-M10790 on inflammatory mediators and epithelial barrier markers were investigated.

RESULTS

L. brevis IBRC-M10790 was able to significantly decrease the proinflammatory cytokines (IL-6, IL-1β, and TNF-α) and increase the anti-inflammatory cytokine (IL-10) in the in vitro co-culture system. In addition, L. brevis increased adherens and tight junction (TJ) markers (ZO-1, E-cadherin, and Occludin) in Caco-2 intestinal epithelial cells. Based on the results, pasteurized L. brevis showed a higher protective effect than live L. brevis.

CONCLUSIONS

Our findings suggest that live and pasteurized forms of L. brevis possess probiotic properties and can mitigate inflammatory conditions in IBD.

Recent advances in in vitro models simulating the female genital tract toward more effective intravaginal therapeutic delivery

INTRODUCTION

Intravaginal drug delivery has emerged as a promising avenue for treating a spectrum of systemic and local female genital tract (FGT) conditions, using biomaterials as carriers or scaffolds for targeted and efficient administration. Much effort has been made to understand the natural barriers of this route and improve the delivery system to achieve an efficient therapeutic response.

AREAS COVERED

In this review, we conducted a comprehensive literature search using multiple databases (PubMed Scopus Web of Science Google Scholar), to discuss the potential of intravaginal therapeutic delivery, as well as the obstacles unique to this route. The in vitro cell models of the FGT and how they can be applied to probing intravaginal drug delivery are then analyzed. We further explore the limitations of the existing models and the possibilities to make them more promising for delivery studies or biomaterial validation. Complementary information is provided by in vitro acellular techniques that may shed light on mucus-drug interaction.

EXPERT OPINION

Advances in 3D models and cell cultures have enhanced our understanding of the FGT, but they still fail to replicate all variables. Future research should aim to use complementary methods, ensure stability, and develop consistent protocols to improve therapy evaluation and create better predictive in vitro models for women's health.

Roles of breast cancer resistance protein and organic anion transporting polypeptide 2B1 in gastrointestinal toxicity induced by SN-38 under inflammatory conditions

Drug transporters are among the factors that determine the pharmacokinetic profiles after drug administration. In this study, we investigated the roles of drug transporters involved in transport of SN-38, which is an active metabolite of irinotecan, in the intestine under inflammatory conditions in vitro and determined their functional consequences. The expression alterations of breast cancer resistance protein (BCRP) and organic anion transporting polypeptide (OATP) 2B1 were determined at the mRNA and protein levels, and the subsequent functional alterations were evaluated via an accumulation study with the representative transporter substrates [prazosin and dibromofluorescein (DBF)] and SN-38. We also determined the cytotoxicity of SN-38 under inflammatory conditions. Decreased BCRP expression and increased OATP2B1 expression were observed under inflammatory conditions in vitro, which led to altered accumulation profiles of prazosin, DBF, and SN-38, and the subsequent cytotoxic profiles of SN-38. Treatment with rifampin or novobiocin supported the significant roles of BCRP and OATP2B1 in the transport and cytotoxic profile of SN-38. Collectively, these results suggest that BCRP and OATP2B1 are involved in the increased cytotoxicity of SN-38 under inflammatory conditions in vitro. Further comprehensive research is warranted to completely understand SN-38-induced gastrointestinal cytotoxicity and aid in the successful treatment of cancer with irinotecan.

Navigating the neuroinflammatory network: insights from diverse cell models

In this Highlights article, we present insights into the use of simple cell lines in neuroinflammation research, highlighting key findings from our recent investigations. Simple cell lines, including HEK, PC12, SHSY5Y, and N2a cells, provide valuable insights into critical signaling pathways and hidden facets of the neuroinflammatory landscape. Focusing on specific outcomes, including the impact of interleukin-6 (IL-6) and acid-sensing ion channels (ASIC1a), the study sheds light on neuroinflammatory processes. Results showcase the potential of diverse cell models in identifying specific molecules and offer a multidimensional perspective on the intricate neuroinflammatory network, paving the way for therapeutic interventions.