Crosstalk between the circadian clock, intestinal stem cell niche, and epithelial cell fate decision.

The circadian rhythm, a 24-h cycle, plays a crucial role in regulating gut physiological processes, particularly the proliferation and differentiation of intestinal epithelial cells, which are essential for gut homeostasis and repair. This review discusses the complex interactions between circadian rhythms, cell cycle regulation, and key signaling pathways (Wnt, Notch, and Hippo) in the context of the intestinal stem cell niche and epithelial cell fate decisions. Key molecules such as brain and muscle ARNT-like 1 (BMAL1), circadian locomotor output cycles kaput (CLOCK), hairy and enhancer of split 1 (Hes1), and Yes-associated protein/transcriptional coactivator with PDZ-binding motif (YAP/TAZ) coordinate stem cell functions with circadian rhythms.

Current Applications of Colorectal Cancer Organoids: A Review.

Colorectal cancer is a prevalent malignancy, with advanced and metastatic forms exhibiting poor treatment outcomes and high relapse rates. To enhance patient outcomes, a comprehensive understanding of the pathophysiological processes and the development of targeted therapies are imperative. The high heterogeneity of colorectal cancer demands precise and personalized treatment strategies.

Mechanisms underlying distinct subcellular localization and regulation of epithelial long myosin light-chain kinase splice variants.

Intestinal epithelia express two long myosin light-chain kinase (MLCK) splice variants, MLCK1 and MLCK2, which differ by the absence of a complete immunoglobulin (Ig)-like domain 3 within MLCK2. MLCK1 is preferentially associated with the perijunctional actomyosin ring at steady state, and this localization is enhanced by inflammatory stimuli including tumor necrosis factor (TNF). Here, we sought to identify MLCK1 domains that direct perijunctional MLCK1 localization and their relevance to disease.

Mesenchymal stromal cells confer breast cancer doxorubicin resistance by producing hyaluronan.

Chemotherapy resistance represents a major cause of therapeutic failure and mortality in cancer patients. Mesenchymal stromal cells (MSCs), an integral component of tumor microenvironment, are known to promote drug resistance. However, the detailed mechanisms remain to be elucidated.

Nuclear receptor modulators inhibit osteosarcoma cell proliferation and tumour growth by regulating the mTOR signaling pathway.

Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. Chemoresistance leads to poor responses to conventional therapy in patients with osteosarcoma. The discovery of novel effective therapeutic targets and drugs is still the main focus of osteosarcoma research.

Nutraceuticals for the Treatment of IBD: Current Progress and Future Directions.

Inflammatory bowel disease (IBD) is a chronic relapsing-remitting inflammatory disease of the gastrointestinal tract. Patients are usually diagnosed in adolescence and early adulthood and need lifelong treatment. In recent years, it has been found that diet plays an important role in the pathogenesis of IBD.

Selective Inhibition of 11β-Hydroxysteroid Dehydrogenase Type 1 Attenuates High-Fat Diet-Induced Hepatic Steatosis in Mice.

Introduction: The effect of 11β-hydroxysteroid dehydrogenase type1 (11β-HSD1) inhibition on hepatic steatosis is incompletely understood. Here, we aimed to determine the therapeutic effect of BVT.2733, a selective 11β-HSD1 inhibitor, on hepatic steatosis.

Quantification of Proliferative and Dead Cells in Enteroids.

The intestinal epithelium acts as a barrier that prevents luminal contents, such as pathogenic microbiota and toxins, from entering the rest of the body. Epithelial barrier function requires the integrity of intestinal epithelial cells. While epithelial cell proliferation maintains a continuous layer of cells that forms a barrier, epithelial damage leads to barrier dysfunction.

Contributions of Myosin Light Chain Kinase to Regulation of Epithelial Paracellular Permeability and Mucosal Homeostasis.

Intestinal barrier function is required for the maintenance of mucosal homeostasis. Barrier dysfunction is thought to promote progression of both intestinal and systemic diseases. In many cases, this barrier loss reflects increased permeability of the paracellular tight junction as a consequence of myosin light chain kinase (MLCK) activation and myosin II regulatory light chain (MLC) phosphorylation.

Inflammation-induced Occludin Downregulation Limits Epithelial Apoptosis by Suppressing Caspase-3 Expression.

Background & Aims: Epithelial tight junctions are compromised in gastrointestinal disease. Processes that contribute to the resulting barrier loss include endocytic occludin removal from the tight junction and reduced occludin expression. Nevertheless, the relatively-normal basal phenotype of occludin knockout (KO) mice has been taken as evidence that occludin does not contribute to gastrointestinal barrier function.

Intracellular MLCK1 diversion reverses barrier loss to restore mucosal homeostasis.

Epithelial barrier loss is a driver of intestinal and systemic diseases. Myosin light chain kinase (MLCK) is a key effector of barrier dysfunction and a potential therapeutic target, but enzymatic inhibition has unacceptable toxicity. Here, we show that a unique domain within the MLCK splice variant MLCK1 directs perijunctional actomyosin ring (PAMR) recruitment.

Interleukin 22 Expands Transit-Amplifying Cells While Depleting Lgr5 Stem Cells via Inhibition of Wnt and Notch Signaling.

Background & Aims: Epithelial regeneration is essential for homeostasis and repair of the mucosal barrier. In the context of infectious and immune-mediated intestinal disease, interleukin (IL) 22 is thought to augment these processes. We sought to define the mechanisms by which IL22 promotes mucosal healing.

In Vitro and In Vivo Approaches to Determine Intestinal Epithelial Cell Permeability.

The intestinal barrier defends against pathogenic microorganism and microbial toxin. Its function is regulated by tight junction permeability and epithelial cell integrity, and disruption of the intestinal barrier function contributes to progression of gastrointestinal and systemic disease. Two simple methods are described here to measure the permeability of intestinal epithelium.

[Hypoxia promotes the growth and invasiveness of prostate cancer cells by down-regulating miR-132 in vitro].

Objective: To explore the expression of miR-132 in prostate cancer and its effects on the growth and invasiveness of prostate cancer cells and the influence of hypoxia on the level of miR-132 and biological behavior of prostate cancer cells.

Methods: Real time PCR was used to measure the expression level of miR-132 in the prostate cancer tissue, analyze its relationship with the clinical stage and Gleason score of prostate cancer, and determine the influence of hypoxia on the miR-132 level in the human prostate cancer PC3 cell line in vitro. Sulfor-hodamine B chromatometry and Matrigel invasion assay were employed to detect the effects of hypoxia and miR-132 mimic plasmid transfection on the viability and invasiveness of PC3 cells in vitro.

MiR-155 up-regulated by TGF-β promotes epithelial-mesenchymal transition, invasion and metastasis of human hepatocellular carcinoma cells .

It has previously been reported that microRNA (miR)-155 is linked to the recurrence and prognosis of hepatocellular carcinoma (HCC) following liver transplantation. However, the role of miR-155 in the invasion and metastasis of HCC cells remains largely unclear. The aim of this study was to investigate the expression of miR-155 in HCC cells and its role in the invasion and migration of HCC cells .

Myosin regulatory light chain phosphorylation is associated with leiomyosarcoma development.

Leiomyosarcoma is a rare malignant smooth muscle tumor which can be very unpredictable. Myosin II is involved in many functions, including cell contraction, migration, and adhesion. The phosphorylation of myosin regulatory light chain (MLC) by myosin light chain kinase (MLCK) determines the activity of Myosin II.

IL-22 Upregulates Epithelial Claudin-2 to Drive Diarrhea and Enteric Pathogen Clearance.

Diarrhea is a host response to enteric pathogens, but its impact on pathogenesis remains poorly defined. By infecting mice with the attaching and effacing bacteria Citrobacter rodentium, we defined the mechanisms and contributions of diarrhea and intestinal barrier loss to host defense. Increased permeability occurred within 2 days of infection and coincided with IL-22-dependent upregulation of the epithelial tight junction protein claudin-2.

Glucocorticoids transcriptionally regulate miR-27b expression promoting body fat accumulation via suppressing the browning of white adipose tissue.

Long-term glucocorticoid (GC) treatment induces central fat accumulation and metabolic dysfunction. We demonstrate that microRNA-27b (miR-27b) plays a central role in the pathogenesis of GC-induced central fat accumulation. Overexpression of miR-27b had the same effects as dexamethasone (DEX) treatment on the inhibition of brown adipose differentiation and the energy expenditure of primary adipocytes.

Occludin OCEL-domain interactions are required for maintenance and regulation of the tight junction barrier to macromolecular flux.

In vitro and in vivo studies implicate occludin in the regulation of paracellular macromolecular flux at steady state and in response to tumor necrosis factor (TNF). To define the roles of occludin in these processes, we established intestinal epithelia with stable occludin knockdown. Knockdown monolayers had markedly enhanced tight junction permeability to large molecules that could be modeled by size-selective channels with radii of ~62.

11β-Hydroxysteroid dehydrogenase type 1 selective inhibitor BVT.2733 protects osteoblasts against endogenous glucocorticoid induced dysfunction.

Pharmacologic glucocorticoids (GCs) inhibit osteoblast function and induce osteoporosis. 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) may play a role in osteoporosis as it regulates GC action at a pre-receptor level by converting inactive GC to its active form. Further, 11β-HSD1 was found increasingly expressed in bone with age.

Altered contractile phenotypes of intestinal smooth muscle in mice deficient in myosin phosphatase target subunit 1.

Background & Aims: The regulatory subunit of myosin light chain phosphatase, MYPT1, has been proposed to control smooth muscle contractility by regulating phosphorylation of the Ca(2+)-dependent myosin regulatory light chain. We generated mice with a smooth muscle-specific deletion of MYPT1 to investigate its physiologic role in intestinal smooth muscle contraction.

Methods: We used the Cre-loxP system to establish Mypt1-floxed mice, with the promoter region and exon 1 of Mypt1 flanked by 2 loxP sites.