Direct Conversion of Human Fibroblasts into Adipocytes Using a Novel Small Molecular Compound: Implications for Regenerative Therapy for Adipose Tissue Defects

Challenges and opportunities in obesity: the role of adipocytes during tissue fibrosis

Obesity is a chronic disease that affects the energy balance of the whole body. In addition to increasing fat mass, tissue fibrosis occurred in white adipose tissue in obese condition. Fibrosis is the over-activation of fibroblasts leading to excessive accumulation of extracellular matrix, which could be caused by various factors, including the status of adipocytes. The morphology of adipocytes responds rapidly and dynamically to nutrient fluctuations. Adaptive hypertrophy of normal adipocytes protects peripheral organs from damage from lipotoxicity. However, the biological behavior of hypertrophic adipocytes in chronic obesity is abnormally altered. Adipocytes lead to fibrotic remodeling of the extracellular matrix by inducing unresolved chronic inflammation, persistent hypoxia, and increasing myofibroblast numbers. Moreover, adipocyte-induced fibrosis not only restricts the flexible expansion and contraction of adipose tissue but also initiates the development of various diseases through cellular autonomic and paracrine effects. Regarding anti-fibrotic therapy, dysregulated intracellular signaling and epigenetic changes represent potential candidate targets. Thus, modulation of adipocytes may provide potential therapeutic avenues for reversing pathological fibrosis in adipose tissue and achieving the anti-obesity purpose.

Rapid direct conversion of bovine non-adipogenic fibroblasts into adipocyte-like cells by a small-molecule cocktail

Introduction: The molecular regulation mechanism of fat deposition in bovine and its improvement on beef quality are important research directions in the livestock industry. The research of molecular mechanisms that govern the regulation and differentiation of adipocytes may conduct to understand the mechanism of obesity, lipid disorders, and fat deposition. In the recent decade, small-molecule compounds have been widely used in reprogramming and transdifferentiation fields, which can promote the induction efficiency, replace exogenous genes, or even induce cell fate conversion alone. Furthermore, small-molecule compound induction is expected to be a novel approach to generate new cell types from somatic cells in vitro and in vivo. Methods: In this study, we established rapid chemically induced platform for transdifferentiation of bovine ear fibroblasts into adipocyte-like cells using a small-molecule cocktail (Repsox, VPA, TTNPB). The chemically induced adipocytes (CiADCs) were characterized by lipid staining, qRT-PCR and WB. Bovine natural adipocytes were used as positive control, and the expression of adipocyte-related marker genes in CiADCs were analyzed. Moreover, RNA-Seq explore the mechanism of RVB in the regulation of Bovine adipocyte transdifferentiation. Results: In this study, the chemically induced adipocytes (CiADCs) could be identified as early as day 6. The CiADCs appeared to be circular and rich of lipid droplets. The adipocyte-specific genes of LPL, PPARγ, IGF1, GPD1, C/EBPδ, ADIPOQ, PCK2, FAS, C/EBPβ, PPARGC1A, C/EBPα, and CFD were detected to be significantly upregulated in both CiADCs and natural adipocytes. Western blot analysis also confirmed the increase C/EBPα and PPARγ protein level in induced adipocytes (CiADCs-6d) treated with RVB. In addition, we also found that the signaling pathways (PPAR signaling pathway, PI3K-Akt signaling pathway, p53 signaling pathway, MAPK signaling pathway, and ECM-receptor interaction) regulated by the DEGs played a vital role in adipogenesis. Discussion: In the present study, a combination of small-molecule compounds RVB was used to transdifferentiate bovine ear fibroblasts into the chemically-induced adipocyte cells (CiADCs) that have a large number of lipid droplets. Importantly, the small-molecule cocktail significantly shortened the reprogramming turnaround time. The morphology of CiADCs is close to the "ring type" of natural differentiated adipocytes on sixth day. And, the CiADCs showed similar adipocyte-specific gene expression patterns to natural adipocytes. Furthermore, RVB increased protein expression of PPARγ and C/EBPα in the chemically-induced adipocytes (CiADCs-6d). Our findings reveal that the signaling pathways of C/EBPα and PPARγ play pivotal roles in this transdifferentiation process. In addition, we also found that the signaling pathways (PPAR signaling pathway, PI3K-Akt signaling pathway, p53 signaling pathway, MAPK signaling pathway, and ECM-receptor interaction) regulated by the DEGs played a vital role in adipogenesis. In general, this study provides valuable evidence to deepen our understanding of the molecular mechanism of small molecule cocktails in regulating adipogenesis.

New Technologies Based on Stem Cell-Therapies in Regenerative Medicine and Reproductive Biology

Stem cells seem to hold major promise for contemporary medicine, one which could almost be more significant than a discovery of DNA and ultimate its relevance for organismal integration in the past century [...].

Topical Simvastatin Improves Lesions of Diffuse Normolipemic Plane Xanthoma by Inhibiting Foam Cell Pyroptosis

Xanthoma pathogenesis is speculated to be associated with oxidized low-density lipoprotein (ox-LDL) deposition, although this remains unclear. Most patients with diffuse plane xanthomas present elevated blood lipid levels, and they benefit from treatment with oral lipid-lowering agents. However, there is no available treatment for diffuse normolipemic plane xanthoma (DNPX). In this study, for the first time, we used a topical simvastatin ointment to treat DNPX in three pediatric patients and observed favorable results. Immunofluorescence staining showed that the pyroptotic pathway was significantly attenuated after topical simvastatin application on the skin lesions of the patients. As ox-LDL deposition was observed in the lesions, we used ox-LDL to build a foam cell model in vitro. In the ox-LDL-induced foam cell formation, simvastatin consistently inhibited pyroptotic activation and inflammation in the macrophages. Additionally, the overexpression of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) or 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase (HMGCR), the known target of statins, reversed the effects of simvastatin. Moreover, gasdermin D (GSDMD) or HMGCR knockdown inhibited ox-LDL-induced pyroptosis. Furthermore, the immunoprecipitation results confirmed the interaction between NLRP3 and HMGCR, and this interaction was inhibited by simvastatin. In conclusion, we demonstrated that topical application of simvastatin ointment might be a promising treatment for DNPX skin lesions and that this therapeutic effect may be related to pyroptosis inhibition via HMGCR inhibition in foam cells. Moreover, xanthoma pathogenesis might be associated with ox-LDL deposition and inflammation.

Multi-Probiotic Lactobacillus Supplementation Improves Liver Function and Reduces Cholesterol Levels in Jeju Native Pigs

Simple Summary

Probiotics are used in the food industry as feed additives to maintain the balance of animal gut microbiota. They are also considered to have potential therapeutic effects against liver diseases. This study showed that dietary Lactobacillus supplementation improved liver function and reduced cholesterol levels in Jeju native pigs, with Toll-like receptors (TLR) signaling as the primary response in the gut against Lactobacillus and TNF-α/IFN-γ as the central mediator cytokines in the gut and liver tissues. Lactobacillus supplementation may be applied to treat metabolic disorders of the liver, especially cholesterol-related disorders, in farm animals.

Abstract

We evaluated the dietary effects of multiple probiotics in Jeju native pigs, using basal diet and multi-probiotic Lactobacillus (basal diet with 1% multi-probiotics) treatments (n = 9 each) for 3 months. We analyzed growth performance, feed efficiency, backfat thickness, blood parameters, hematological profiles, adipokines, and immune-related cytokines in pig tissues. Average daily gain, feed intake, feed efficiency, backfat thickness, and body weight were not significantly different between both groups. In Lactobacillus group, total protein (p < 0.08) and bilirubin (p < 0.03) concentrations increased; blood urea nitrogen (p < 0.08), alkaline phosphatase (p < 0.08), and gamma-glutamyltransferase (p < 0.08) activities decreased. Lactobacillus group showed decreased adiponectin (p < 0.05), chemerin (p < 0.05), and visfatin expression in adipose tissues, and increased TLR4 (p < 0.05), MYD88 (p < 0.05), TNF-α (p < 0.001), and IFN-γ (p < 0.001) expression in the liver. Additionally, NOD1 (p < 0.05), NOD2 (p < 0.01), and MYD88 (p < 0.05) mRNA levels in proximal colon tissue upregulated significantly. Colon, longissimus dorsi muscle, fat tissue, and liver histological analyses revealed no significant differences between the groups. Conclusively, Lactobacillus supplementation improved liver function and reduced cholesterol levels. Its application may treat metabolic liver disorders, especially cholesterol-related disorders.