Colonic healing requires Wnt produced by epithelium as well as Tagln+ and Acta2+ stromal cells

A Nerve-Fibroblast Axis in Mammalian Lung Fibrosis

Fibrosis contributes to incurable pathologies in vital organs including the lung. Myofibroblasts are fibrogenic effector cells that accumulate via incompletely understood mechanisms. We discovered that α1-adrenoreceptor expressing myofibroblasts receive sympathetic nerve-derived noradrenergic inputs in fibrotic mouse and human lungs. We combined optical clearing, whole lung imaging, cell-specific gene deletion in sympathetic nerves and myofibroblasts, pharmacologic interventions, sympathetic nerve co-culture and precision-cut lung slices, with analysis of bronchoalveolar lavage fluid, lung tissues, single-cell RNA sequencing datasets, and isolated lung fibroblasts from patients with diverse forms of pulmonary fibrosis to characterize a fibrogenic unit comprised of aberrantly patterned sympathetic nerves and α1-adrenoreceptor subtype D expressing myofibroblasts. The discovery of this previously undefined nerve-fibroblast axis that is conserved across species demonstrates the pivotal contribution of nerves to tissue remodeling and heralds a novel paradigm in fibrosis research.

RTCB deficiency triggers colitis in mice by influencing the NF-κB and Wnt/β-catenin signaling pathways

RNA terminal phosphorylase B (RTCB) has been shown to play a significant role in multiple physiological processes. However, the specific role of RTCB in the mouse colon remains unclear. In this study, we employ a conditional knockout mouse model to investigate the effects of RTCB depletion on the colon and the potential molecular mechanisms. We assess the efficiency and phenotype of Rtcb knockout using PCR, western blot analysis, histological staining, and immunohistochemistry. Compared with the control mice, the Rtcb-knockout mice exhibit compromised colonic barrier integrity and prominent inflammatory cell infiltration. In the colonic tissues of Rtcb-knockout mice, the protein levels of TNF-α, IL-8, and p-p65 are increased, whereas the levels of IKKβ and IκBα are decreased. Moreover, the level of GSK3β is increased, whereas the levels of Wnt3a, β-catenin, and LGR5 are decreased. Collectively, our findings unveil a close association between RTCB and colonic tissue homeostasis and demonstrate that RTCB deficiency can lead to dysregulation of both the NF-κB and Wnt/β-catenin signaling pathways in colonic cells.

The emerging roles of deep crypt secretory cells in colonic physiology

Deep crypt secretory (DCS) cells are a population of epithelial cells located at the colonic crypt base that share some similarities to Paneth and goblet cells. They were initially defined as c-Kit expressing cells, though subsequent work showed that they are more specifically marked by Reg4 in the murine colon. The best-understood function of DCS cells at present is supporting the stem cell niche by generating Notch and EGF ligands. However, as these cells also express immunoregulatory (e.g., Ccl6) and host defense (e.g., Retnlb) genes, it is likely they have additional functions in maintaining colonic health outside of maintenance of the stem niche. Recent advances in single-cell transcriptomic profiling hint at additional epithelial and immune roles that may exist for these cells and have aided in elucidating their developmental lineage. This review highlights the emerging evidence supporting a crucial role for DCS cells in intestinal physiology, the current understanding of how these cells are regulated, and their potential role(s) in colonic disease.

Fetal Muse-based therapy prevents lethal radio-induced gastrointestinal syndrome by intestinal regeneration

BACKGROUND

Human multilineage-differentiating stress enduring (Muse) cells are nontumorigenic endogenous pluripotent-like stem cells that can be easily obtained from various adult or fetal tissues. Regenerative effects of Muse cells have been shown in some disease models. Muse cells specifically home in damaged tissues where they exert pleiotropic effects. Exposition of the small intestine to high doses of irradiation (IR) delivered after radiotherapy or nuclear accident results in a lethal gastrointestinal syndrome (GIS) characterized by acute loss of intestinal stem cells, impaired epithelial regeneration and subsequent loss of the mucosal barrier resulting in sepsis and death. To date, there is no effective medical treatment for GIS. Here, we investigate whether Muse cells can prevent lethal GIS and study how they act on intestinal stem cell microenvironment to promote intestinal regeneration.

METHODS

Human Muse cells from Wharton's jelly matrix of umbilical cord (WJ-Muse) were sorted by flow cytometry using the SSEA-3 marker, characterized and compared to bone-marrow derived Muse cells (BM-Muse). Under gas anesthesia, GIS mice were treated or not through an intravenous retro-orbital injection of 50,000 WJ-Muse, freshly isolated or cryopreserved, shortly after an 18 Gy-abdominal IR. No immunosuppressant was delivered to the mice. Mice were euthanized either 24 h post-IR to assess early small intestine tissue response, or 7 days post-IR to assess any regenerative response. Mouse survival, histological stainings, apoptosis and cell proliferation were studied and measurement of cytokines, recruitment of immune cells and barrier functional assay were performed.

RESULTS

Injection of WJ-Muse shortly after abdominal IR highly improved mouse survival as a result of a rapid regeneration of intestinal epithelium with the rescue of the impaired epithelial barrier. In small intestine of Muse-treated mice, an early enhanced secretion of IL-6 and MCP-1 cytokines was observed associated with (1) recruitment of monocytes/M2-like macrophages and (2) proliferation of Paneth cells through activation of the IL-6/Stat3 pathway.

CONCLUSION

Our findings indicate that a single injection of a small quantity of WJ-Muse may be a new and easy therapeutic strategy for treating lethal GIS.

Histone deacetylase inhibitor belinostat regulates metabolic reprogramming in killing KRAS-mutant human lung cancer cells

Kirsten rat sarcoma virus (KRAS) oncogene, found in 20%-25% of lung cancer patients, potentially regulates metabolic reprogramming and redox status during tumorigenesis. Histone deacetylase (HDAC) inhibitors have been investigated for treating KRAS-mutant lung cancer. In the current study, we investigate the effect of HDAC inhibitor (HDACi) belinostat at clinically relevant concentration on nuclear factor erythroid 2-related factor 2 (NRF2) and mitochondrial metabolism for the treatment of KRAS-mutant human lung cancer. LC-MS metabolomic study of belinostat on mitochondrial metabolism was performed in G12C KRAS-mutant H358 non-small cell lung cancer cells. Furthermore, l-methionine (methyl-13 C) isotope tracer was used to explore the effect of belinostat on one-carbon metabolism. Bioinformatic analyses of metabolomic data were performed to identify the pattern of significantly regulated metabolites. To study the effect of belinostat on redox signaling ARE-NRF2 pathway, luciferase reporter activity assay was done in stably transfected HepG2-C8 cells (containing pARE-TI-luciferase construct), followed by qPCR analysis of NRF2 and its target gene in H358 cells, which was further confirmed in G12S KRAS-mutant A549 cells. Metabolomic study reveals significantly altered metabolites related to redox homeostasis, including tricarboxylic acid (TCA) cycle metabolites (citrate, aconitate, fumarate, malate, and α-ketoglutarate); urea cycle metabolites (Arginine, ornithine, argino-succinate, aspartate, and fumarate); and antioxidative glutathione metabolism pathway (GSH/GSSG and NAD/NADH ratio) after belinostat treatment. 13 C stable isotope labeling data indicates potential role of belinostat in creatine biosynthesis via methylation of guanidinoacetate. Moreover, belinostat downregulated the expression of NRF2 and its target gene NAD(P)H:quinone oxidoreductase 1 (NQO1), indicating anticancer effect of belinostat is mediated, potentially via Nrf2-regulated glutathione pathway. Another HDACi panobinostat also showed potential anticancer effect in both H358 and A549 cells via Nrf2 pathway. In summary, belinostat is effective in killing KRAS-mutant human lung cancer cells by regulating mitochondrial metabolism which could be used as biomarkers for preclinical and clinical studies.

Virtual screening-molecular docking-activity evaluation of Ailanthus altissima (Mill.) swingle bark in the treatment of ulcerative colitis

BACKGROUND

The dried bark of Ailanthus altissima (Mill.) Swingle is widely used in traditional Chinese medicine for the treatment of ulcerative colitis. The objective of this study was to explore the therapeutic basis of the dried bark of Ailanthus altissima (Mill.) Swingle for the treatment of ulcerative colitis based on Virtual Screening-Molecular Docking-Activity Evaluation technology.

METHODS

By searching the Traditional Chinese Medicine Systems Pharmacology TCMSP Database and Analysis Platform, 89 compounds were obtained from the chemical components of the dried bark of Ailanthus altissima (Mill.) Swingle. Then, after preliminarily screening the compounds based on Lipinski's rule of five and other relevant conditions, the AutoDock Vina molecular docking software was used to evaluate the affinity of the compounds to ulcerative colitis-related target proteins and their binding modes through use of the scoring function to identify the best candidate compounds. Further verification of the compound's properties was achieved through in vitro experiments.

RESULTS

Twenty-two compounds obtained from the secondary screening were molecularly docked with ulcerative colitis-related target proteins (IL-1R, TLR, EGFR, TGFR, and Wnt) using AutoDock Vina. The free energies of the highest scoring compounds binding to the active cavity of human IL-1R, TLR, EGFR, TGFR, and Wnt proteins were - 8.7, - 8.0, - 9.2, - 7.7, and - 8.5 kcal/mol, respectively. The potential compounds, dehydrocrebanine, ailanthone, and kaempferol, were obtained through scoring function and docking mode analysis. Furthermore, the potential compound ailanthone (1, 3, and 10 µM) was found to have no significant effect on cell proliferation, though at 10 µM it reduced the level of pro-inflammatory factors caused by lipopolysaccharide.

CONCLUSION

Among the active components of the dried bark of Ailanthus altissima (Mill.) Swingle, ailanthone plays a major role in its anti-inflammatory properties. The present study shows that ailanthone has advantages in cell proliferation and in inhibiting of inflammation, but further animal research is needed to confirm its pharmaceutical potential.

The role of Evi/Wntless in exporting Wnt proteins

Intercellular communication by Wnt proteins governs many essential processes during development, tissue homeostasis and disease in all metazoans. Many context-dependent effects are initiated in the Wnt-producing cells and depend on the export of lipidated Wnt proteins. Although much focus has been on understanding intracellular Wnt signal transduction, the cellular machinery responsible for Wnt secretion became better understood only recently. After lipid modification by the acyl-transferase Porcupine, Wnt proteins bind their dedicated cargo protein Evi/Wntless for transport and secretion. Evi/Wntless and Porcupine are conserved transmembrane proteins, and their 3D structures were recently determined. In this Review, we summarise studies and structural data highlighting how Wnts are transported from the ER to the plasma membrane, and the role of SNX3-retromer during the recycling of its cargo receptor Evi/Wntless. We also describe the regulation of Wnt export through a post-translational mechanism and review the importance of Wnt secretion for organ development and cancer, and as a future biomarker.

Role of Wnt signaling in the maintenance and regeneration of the intestinal epithelium

The intestinal epithelium plays a key role in digestion and protection against external pathogens. This tissue presents a high cellular turnover with the epithelium being completely renewed every 5days, driven by intestinal stem cells (ISCs) residing in the crypt bases. To sustain this dynamic renewal of the intestinal epithelium, the maintenance, proliferation, and differentiation of ISCs must be precisely controlled. One of the central pathways supporting ISC maintenance and dynamics is the Wnt pathway. In this chapter, we examine the role of Wnt signaling in intestinal epithelial homeostasis and tissue regeneration, including mechanisms regulating ISC identity and fine-tuning of Wnt pathway activation. We extensively discuss the contribution of the stem cell niche in maintaining Wnt signaling in the intestinal crypts that support ISC functions. The integration of these findings highlights the complex interplay of multiple niche signals and cellular components sustaining ISC behavior and maintenance, which together supports the immense plasticity of the intestinal epithelium.