Tributyrin, a Butyrate Pro-Drug, Primes Satellite Cells for Differentiation by Altering the Epigenetic Landscape

Impact of high-fat diet on ovarian epigenetics: Insights from altered intestinal butyric acid levels

Objective

To investigate the effects of a high-fat diet (HFD) on the gut bacterium Roseburia intestinalis and butyric acid levels, and to assess their impact on ovarian function and epigenetic markers in mice.

Methods

A total of 20 female ICR mice aged 4 weeks were randomly assigned to two groups and fed either a control diet (CD) or an HFD for 36 weeks. Post-intervention, ileal contents were analyzed for the quantification of butyric acid using ELISA, while feces were obtained for Roseburia intestinalis expression assessment via qPCR. Histological evaluations of intestinal and ovarian tissues included H&E and Alcian Blue-Periodic Acid Schiff (AB-PAS) staining, alongside immunohistochemical analysis for F4/80, and immunofluorescent detection of Occludin, ZO-1, 5 mC, and H3K36me3. Ovarian health was assessed through follicle counts and morphological evaluations. Statistical analyses were performed using GraphPad Prism 8.0, with P < 0.05 considered significant.

Results

After 36 weeks, the HFD group showed significantly higher body weight compared to the CD group (P < 0.01). The HFD led to a decrease in Roseburia intestinalis and butyric acid levels, a reduction in intestinal goblet cells, and an increase in intestinal inflammation. Histological analyses revealed impaired ovarian follicular development and enhanced inflammation in the HFD mice, with immunofluorescent staining showing downregulation of the ovarian epigenetic markers 5 mC and H3K36me3.

Conclusion

Our study demonstrates that long-term HFD negatively impacts ovarian function and epigenetic regulation. We found decreased levels of the gut bacterium Roseburia intestinalis and its metabolite, butyric acid, which contribute to these adverse effects. Additionally, the associated intestinal inflammation and compromised mucosal barrier may contribute to these adverse outcomes on female reproductive health.

Satellite cell contribution to disease pathology in Duchenne muscular dystrophy

Progressive muscle weakness and degeneration characterize Duchenne muscular dystrophy (DMD), a lethal, x-linked neuromuscular disorder that affects 1 in 5,000 boys. Loss of dystrophin protein leads to recurrent muscle degeneration, progressive fibrosis, chronic inflammation, and dysfunction of skeletal muscle resident stem cells, called satellite cells. Unfortunately, there is currently no cure for DMD. In this mini review, we discuss how satellite cells in dystrophic muscle are functionally impaired, and how this contributes to the DMD pathology, and the tremendous potential of restoring endogenous satellite cell function as a viable treatment strategy to treat this debilitating and fatal disease.

Tributyrin Intake Attenuates Angiotensin II-Induced Abdominal Aortic Aneurysm in LDLR-/- Mice

Abdominal aortic aneurysm (AAA) is a multifactorial cardiovascular disease with a high risk of death, and it occurs in the infrarenal aorta with vascular dilatation. High blood pressure acts on the aortic wall, resulting in rupture and causing life-threatening intra-abdominal hemorrhage. Vascular smooth muscle cell (VSMC) dysregulation and extracellular matrix (ECM) degradation, especially elastin breaks, contribute to structural changes in the aortic wall. The pathogenesis of AAA includes the occurrence of oxidative stress, inflammatory cell infiltration, elastic fiber fragmentation, VSMC apoptosis, and phenotypic transformation. Tributyrin (TB) is decomposed by intestinal lipase and has a function similar to that of butyrate. Whether TB has a protective effect against AAA remains uncertain. In the present study, we established an AAA murine model by angiotensin II (AngII) induction in low-density lipoprotein receptor knockout (LDLR^-/-) mice and investigated the effects of orally administered TB on the AAA size, ratio of macrophage infiltration, levels of matrix metalloproteinase (MMP) expression, and epigenetic regulation. TB attenuates AngII-induced AAA size and decreases elastin fragmentation, macrophage infiltration, and MMP expression in the medial layer of the aorta and reduces the levels of SBP (systolic blood pressure, p < 0.001) and MMP-2 (p < 0.02) in the serum. TB reduces the AngII-stimulated expression levels of MMP2 (p < 0.05), MMP9 (p < 0.05), MMP12, and MMP14 in human aortic smooth muscle cells (HASMCs). Moreover, TB and valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, suppress AngII receptor type 1 (AT1R, p < 0.05) activation and increase the expression of acetyl histone H3 by HDAC activity inhibition (p < 0.05). Our findings suggest that TB exerts its protective effect by suppressing the activation of HDAC to attenuate the AngII-induced AT1R signaling cascade.

Metabolic-epigenetic nexus in regulation of stem cell fate

Stem cell fate determination is one of the central questions in stem cell biology, and although its regulation has been studied at genomic and proteomic levels, a variety of biological activities in cells occur at the metabolic level. Metabolomics studies have established the metabolome during stem cell differentiation and have revealed the role of metabolites in stem cell fate determination. While metabolism is considered to play a biological regulatory role as an energy source, recent studies have suggested the nexus between metabolism and epigenetics because several metabolites function as cofactors and substrates in epigenetic mechanisms, including histone modification, DNA methylation, and microRNAs. Additionally, the epigenetic modification is sensitive to the dynamic metabolites and consequently leads to changes in transcription. The nexus between metabolism and epigenetics proposes a novel stem cell-based therapeutic strategy through manipulating metabolites. In the present review, we summarize the possible nexus between metabolic and epigenetic regulation in stem cell fate determination, and discuss the potential preventive and therapeutic strategies via targeting metabolites.