Mesenteric adipose-derived exosomal TINAGL1 enhances intestinal fibrosis in Crohn's Disease via SMAD4.

INTRODUCTION: Crohn's Disease (CD) is a chronic inflammatory condition characterized by intestinal fibrosis, severely impacting patient quality of life. The molecular mechanisms driving this fibrosis remain inadequately understood. Recent evidence implicates mesenteric adipose tissue (MAT) in CD pathogenesis, particularly through its exosome secretion, which may influence fibrogenic pathways. Understanding the role of MAT-derived exosomes is crucial for unraveling these molecular processes. OBJECTIVES: This study aims to elucidate the role of MAT-derived exosomes in CD-related intestinal fibrosis. We focus on investigating their molecular composition and the potential impact on fibrosis progression, with an emphasis on identifying novel therapeutic targets. METHODS: We induced chronic intestinal inflammation in mice using dinitrobenzene sulfonic acid (DNBS), simulating CD-like fibrosis. Exosomes were isolated from DNBS-treated mice (MG) and normal controls (NG) for characterization using electron microscopy and proteomic analysis. Additionally, human colonic fibroblasts were exposed to exosomes from CD patients and healthy individuals, with subsequent assessment of fibrogenesis through proteomic and RNA sequencing analyses. RESULTS: Proteomic analyses revealed a significant activation of the TGF-ß signaling pathway in MG-treated mice compared to controls, correlating with enhanced intestinal fibrosis. In vitro experiments demonstrated that colonic fibroblasts exposed to CD patient-derived exosomes exhibited increased fibrogenic activity. Protein docking and co-immunoprecipitation studies suggested a critical interaction between TINAGL1 and SMAD4, enhancing fibrosis. Importantly, in vivo experiments corroborated that recombinant TINAGL1 protein exacerbated DNBS-induced intestinal fibrosis. CONCLUSION: Our findings highlight the pivotal role of MAT-derived exosomes, particularly those carrying TINAGL1, in the progression of intestinal fibrosis in CD. The involvement of the TGF-ß signaling pathway, especially the SMAD4 protein, offers new insights into the molecular mechanisms of CD-related fibrosis and presents potential targets for therapeutic intervention.

A multiplexed time-resolved fluorescence resonance energy transfer ultrahigh-throughput screening assay for targeting the SMAD4-SMAD3-DNA complex.

The transforming growth factor-beta (TGFß) signaling pathway plays crucial roles in the establishment of an immunosuppressive tumor microenvironment, making anti-TGFß agents a significant area of interest in cancer immunotherapy. However, the clinical translation of current anti-TGFß agents that target upstream cytokines and receptors remains challenging. Therefore, the development of small-molecule inhibitors specifically targeting SMAD4, the downstream master regulator of the TGFß pathway, would offer an alternative approach with significant therapeutic potential for anti-TGF-ß signaling. In this study, we present the development of a cell lysate-based multiplexed time-resolved fluorescence resonance energy transfer (TR-FRET) assay in an ultrahigh-throughput screening (uHTS) 1536-well plate format. This assay enables simultaneous monitoring of the protein‒protein interaction between SMAD4 and SMAD3, as well as the protein‒DNA interaction between SMADs and their consensus DNA-binding motif. The multiplexed TR-FRET assay exhibits high sensitivity, allowing the dynamic analysis of the SMAD4-SMAD3-DNA complex at single-amino acid resolution. Moreover, the multiplexed uHTS assay demonstrates robustness for screening small-molecule inhibitors. Through a pilot screening of an FDA-approved bioactive compound library, we identified gambogic acid and gambogenic acid as potential hit compounds. These proof-of-concept findings underscore the utility of our optimized multiplexed TR-FRET platform for large-scale screening to discover small-molecule inhibitors that target the SMAD4-SMAD3-DNA complex as novel anti-TGFß signaling agents.

[Therapeutic effect of Jingfang Granules on CCl_4-induced liver fibrosis in mice and its mechanism].

To investigate the therapeutic effect of Jingfang Granules on carbon tetrachloride(CCl_4)-induced liver fibrosis in mice and its mechanism. Forty-nine 8-week-old male C57 BL/6 J mice were randomly divided into a blank group, a CCl_4 group, a silybin group(positive control, 100 mg·kg~(-1))+CCl_4, a Jingfang high-dose(16 g·kg~(-1)) group, a Jingfang high-dose(16 g·kg~(-1))+CCl_4 group, a Jingfang medium-dose(8 g·kg~(-1))+CCl_4 group, and a Jingfang low-dose(4 g·kg~(-1))+CCl_4 group, with 7 mice in each group. The mice in the blank group and Jingfang high-dose group were intraperitoneally injected olive oil solution, and mice in other groups were intraperitoneally injected with 10% CCl_4 olive oil solution(5 mL·kg~(-1)) to induce liver fibrosis, twice a week with an interval of 3 d, for 8 weeks. At the same time, except for the blank group and CCl_4 group, which were given deionized water, the mice in other groups were given the corresponding dose of drugs by gavage once daily for 8 weeks with the gavage volume of 10 mL·kg~(-1). All mice were fasted and freely drank for 12 h after the last administration, and then the eyeballs were removed for blood collection. The liver and spleen were collected, and the organ index was calculated. The levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), total bile acid(TBA), and triglyceride(TG) in the serum of mice were detected by an automated analyzer. Tumor necrosis factor-α(TNF-α), interleukin-6(IL-6) and interleukin-1ß(IL-1ß) levels were detected by enzyme-linked immunosorbent assay(ELISA). Kits were used to detect the contents of superoxide dismutase(SOD), malondialdehyde(MDA), and glutathione(GSH) in the liver tissue. Pathological changes in the liver tissue were observed by hematoxylin-eosin(HE), Masson, and Sirius red staining. Western blot was used to detect protein expressions of transforming growth factor-ß(TGF-ß), α-smooth muscle actin(α-SMA) and Smad4 in the liver tissue. The results indicated that Jingfang Granules significantly reduced the organ index, levels of ALT, AST, TBA,TG, TNF-α, IL-6, and IL-1ß in the serum, and the content of MDA in the liver tissue of mice with CCl_4-induced liver fibrosis. Jingfang Granules also significantly increased the content of SOD and GSH in the liver tissue. Meanwhile, Jingfang Granules down-regulated the protein levels of TGF-ß, α-SMA, and Smad4. Furthermore, Jingfang Granules had no significant effect on the liver tissue morphology and the above indexes in the normal mice. In conclusion, Jingfang Granules has obvious therapeutic effect on CCl_4-induced liver fibrosis, and its mechanism may be related to reducing the expression of pro-inflammatory factors, anti-oxidation, and regulating TGF-ß/Smad4 signaling pathway.

TGF-ß/SMAD4 signaling pathway activates the HAS2-HA system to regulate granulosa cell state.

Both TGF-ß/SMAD4 signaling pathway and HAS2-HA system have been shown to control granulosa cell (GC) state in mammalian ovary. However, the regulatory relationship between TGF-ß/SMAD4 signaling pathway and HA system in GCs is not well known. Here, we report that the TGF-ß/SMAD4 signaling pathway activates the HAS2-HA system by binding directly to the HAS2 promoter, ultimately controlling the GC state via the CD44-Caspase3 axis. SMAD4-induced HAS2 expression, HAS2-driven HA secretion, and HAS2-mediated GC state (proliferation and apoptosis) by interacting directly with the promoter region of the HAS2 gene. The CD44-Caspase3 axis, located downstream of the HAS2-HA system, was also activated by SMAD4 and the TGF-ß/SMAD4 signaling pathway. However, there was no feedback regulation of the TGF-ß/SMAD4 signaling pathway by the HAS2-HA system in GCs. In addition, we found that miRNA-26b attenuated HAS2 expression via SMAD4-dependent and -independent mechanisms. Our findings provide compelling evidence that HAS2 is a direct transcriptional target of SMAD4. They also reveal a novel mechanism by which the TGF-ß/SMAD4 signaling pathway controls the GC state and alters the structural components of GCs in porcine ovaries.