Autophagy perturbation upon acute pyrethroid treatment impacts adipogenic commitment of mesenchymal stem cells.

Environmental chemical exposure can cause dysregulation in adipogenesis that can result in metabolic syndrome, which includes insulin resistance, type 2 diabetes, cardiovascular disease, as well as excessive body weight. The role of autophagy in adipocyte differentiation is debatable since both positive and negative effects have been reported. Type-I and type-II synthetic pyrethroids α-cypermethrin (CPM) and permethrin (PER), respectively, are reported to increase adipogenesis in vitro and in vivo. However, it is not known how these pyrethroids affect mesenchymal stem cells (MSCs). Thus, this study focused on evaluating the effect of pyrethroids (CPM and PER) pre-treatment (24 h) on MSC commitment and the regulatory role of autophagy in adipogenic lineage commitment. The formation of adipocytes was observed through nile red staining, perilipin expression by immunoflourescence, and adipogenic markers PPARγ, C/EBPα, and FABP4 by western blotting. It was found that the adipogenic differentiation ability of MSCs was significantly increased upon CPM or PER pre-treatment at 100 µM concentration as evident by lipid accumulation and enhanced expression of adipogenic markers. To assess the involvement of autophagy, the expression of p62 and LC3II were evaluated following pre-treatment. Immunoblotting results revealed an increased expression of p62 and LC3II in CPM or PER pretreated MSCs suggesting CPM and PER mediated inhibition of autophagy at 24 h. Further, an increase was observed in adipogenesis upon CPM or PER pre-treatment in combination with chloroquine, while use of rapamycin during pre-treatment abrogated the effect of CPM and PER. Thus, this study concludes that CPM or PER pre-treatment increases the adipogenic differentiation of MSCs. Since chloroquine also demonstrated similar adipogenic response, it further highlights that 24 h pre-treatment with autophagy modulators to inhibit basal autophagy primes MSCs towards adipogenic lineage.

Tensin-3 is involved in osteogenic versus adipogenic fate of human bone marrow stromal cells.

BACKGROUND: The tightly controlled balance between osteogenic and adipogenic differentiation of human bone marrow-derived stromal cells (BMSCs) is critical to maintain bone homeostasis. Age-related osteoporosis is characterized by low bone mass with excessive infiltration of adipose tissue in the bone marrow compartment. The shift of BMSC differentiation from osteoblasts to adipocytes could result in bone loss and adiposity. METHODS: TNS3 gene expression during osteogenic and adipogenic differentiation of BMSCs was evaluated by qPCR and Western blot analyses. Lentiviral-mediated knockdown or overexpression of TNS3 was used to assess its function. The organization of cytoskeleton was examined by immunofluorescent staining at multiple time points. The role of TNS3 and its domain function in osteogenic differentiation were evaluated by ALP activity, calcium assay, and Alizarin Red S staining. The expression of Rho-GTP was determined using the RhoA pull-down activation assay. RESULTS: Loss of TNS3 impaired osteogenic differentiation of BMSCs but promoted adipogenic differentiation. Conversely, TNS3 overexpression hampered adipogenesis while enhancing osteogenesis. The expression level of TNS3 determined cell shape and cytoskeletal reorganization during osteogenic differentiation. TNS3 truncation experiments revealed that for optimal osteogenesis to occur, all domains proved essential. Pull-down and immunocytochemical experiments suggested that TNS3 mediates osteogenic differentiation through RhoA. CONCLUSIONS: Here, we identify TNS3 to be involved in BMSC fate decision. Our study links the domain structure in TNS3 to RhoA activity via actin dynamics and implicates an important role for TNS3 in regulating osteogenesis and adipogenesis from BMSCs. Furthermore, it supports the critical involvement of cytoskeletal reorganization in BMSC differentiation.

DHA-Provoked Reduction in Adipogenesis and Glucose Uptake Could Be Mediated by Gps2 Upregulation in Immature 3T3-L1 Cells.

The signaling pathway of fatty acids in the context of obesity is an extensively explored topic, yet their primary mechanism of action remains incompletely understood. This study aims to examine the effect of docosahexaenoic acid (DHA) on some crucial aspects of adipogenesis in differentiating 3T3-L1 cells, using palmitic acid-treated (PA), standard differentiated, and undifferentiated adipocytes as controls. Employing 60 µM DHA or PA, 3T3-L1 preadipocytes were treated from the onset of adipogenesis, with negative and positive controls included. After eight days, we performed microscopic observations, cell viability assays, the determination of adiponectin concentration, intracellular lipid accumulation, and gene expression analysis. Our findings demonstrated that DHA inhibits adipogenesis, lipolysis, and glucose uptake by suppressing peroxisome proliferator-activated receptor gamma (Pparg) and G-protein coupled receptor 120 (Gpr120) gene expression. Cell cytotoxicity was ruled out as a causative factor, and ß-oxidation involvement was suspected. These results challenge the conventional belief that omega-3 fatty acids, acting as Pparg and Gpr120 agonists, promote adipogenesis and enhance insulin-dependent glucose cell flux. Moreover, we propose a novel hypothesis suggesting the key role of the co-repressor G protein pathway suppressor 2 in mediating this process. Additional investigations are required to elucidate the molecular mechanisms driving DHA's anti-adipogenic effect and its broader health implications.

Molecular Identification and Acid Stress Response of an Acidithiobacillus thiooxidans Strain Isolated from Rio Tinto (Spain).

Acidithiobacillus thiooxidans is of paramount importance in the development of biomining technologies. Being widely recognized as an extreme acidophile, extensive research has been dedicated to understanding its significant role in the extraction of several ores in recent years. However, there still exist significant molecular uncertainties surrounding this species. This study focuses on developing a taxonomic assignment method based on the sequencing of the 16S-5S rRNA cluster, along with a qPCR-based technology enabling precise growth determination. Additionally, an approach to understanding its response to acid stress is explored through RT-PCR and MALDI-TOF analysis. Our findings indicate that when subjected to pH levels below 1, the cell inhibits central (carbon fixation and metabolism) and energy (sulfur metabolism) metabolism, as well as chaperone synthesis, suggesting a potential cellular collapse. Nevertheless, the secretion of ammonia is enhanced to raise the environmental pH, while fatty acid synthesis is upregulated to reinforce the cell membrane.

TMT-Based Quantitative Proteomics Analysis Reveals Differentially Expressed Proteins between Different Sources of hMSCs.

Mesenchymal stem cells (MSCs) are an attractive therapeutic tool for tissue engineering and regenerative medicine owing to their regenerative and trophic properties. The best-known and most widely used are bone marrow MSCs, which are currently being harvested and developed from a wide range of adult and perinatal tissues. MSCs from different sources are believed to have different secretion potentials and production, which may influence their therapeutic effects. To confirm this, we performed a quantitative proteomic analysis based on the TMT technique of MSCs from three different sources: Wharton's jelly (WJ), dental pulp (DP), and bone marrow (BM). Our analysis focused on MSC biological properties of interest for tissue engineering. We identified a total of 611 differentially expressed human proteins. WJ-MSCs showed the greatest variation compared with the other sources. WJ produced more extracellular matrix (ECM) proteins and ECM-affiliated proteins and proteins related to the inflammatory and immune response processes. BM-MSCs expressed more proteins involved in osteogenic, adipogenic, neuronal, or muscular differentiation and proteins involved in paracrine communication. Compared to the other sources, DP-MSCs overexpressed proteins involved in the exocytosis process. The results obtained confirm the existence of differences between WJ, DP, and BM-MSCs and the need to select the MSC origin according to the therapeutic objective sought.

Identification and Classification of Long Non-Coding RNAs in the Mammary Gland of the Holstein Cow.

The mammary glands, responsible for milk secretion, are regulated at a local level by various hormones, growth factors, non-coding RNAs, and other elements. Recent research has discovered the presence of lncRNAs in these glands, with suggestions that they may be essential for the maintenance and function of mammary glands. Besides directly controlling the gene and protein expression, lncRNAs are believed to play a significant part in numerous physiological and pathological processes. This study focused on examining the mammary gland tissues of Chinese Holstein cows, to identify and categorize long non-coding RNAs (lncRNAs). The research intended to distinguish lncRNAs in the mammary tissues of Holstein cows and contrast them between lactation and non-lactation periods. In this study, mammary gland tissues were sampled from three Holstein cows in early lactation (n = 3, 30 days postpartum) and non-lactation (n = 3, 315 days postpartum) on a large dairy farm in Jiangsu province. Mammary tissue samples were collected during early lactation and again during non-lactation. In total, we detected 1905 lncRNAs, with 57.3% being 500 bp and 612 intronic lncRNAs. The exon count for lncRNAs varied from 2 to 10. It was observed that 96 lncRNA expressions markedly differed between the two stages, with 83 genes being upregulated and 53 downregulated. Enrichment analysis results revealed that Gene Ontology (GO) analysis was primarily abundant in cellular processes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that target genes were predominantly abundant in metabolic pathways, fatty acid biosynthesis, the immune system, and glycosphingolipid biosynthesis. This study analyzed the expression profile and characteristics of lncRNAs in the mammary gland tissues of Holstein cows during both lactation and non-lactation stages, forming a foundation for further investigation into the functional roles of lncRNAs in Holstein cows throughout lactation.

Dermal white adipose tissue development and metabolism: The role of transcription factor Foxn1.

Intradermal adipocytes form dermal white adipose tissue (dWAT), a unique fat depot localized in the lower layer of the dermis. However, recognition of molecular factors regulating dWAT development, homeostasis, and bioactivity is limited. Using Foxn1-/- and Foxn1+/+ mice, we demonstrated that epidermally expressed Foxn1 regulates dWAT development and defines the adipogenic capacity of dermal fibroblasts. In intact and post-wounded skin, Foxn1 contributes to the initial stimulation of dWAT adipogenesis and participates in the modulation of lipid metabolism processes. Furthermore, Foxn1 activity strengthens adipogenic processes through Bmp2 and Igf2 signaling and regulates lipid metabolism in differentiated dermal fibroblasts. The results reveal the contribution of Foxn1 to dWAT metabolism, thus identifying possible targets for modulation and regulation of dWAT in physiological and pathological processes in the skin.

Fatty acid elongation by ELOVL6 hampers remyelination by promoting inflammatory foam cell formation during demyelination.

A hallmark of multiple sclerosis (MS) is the formation of multiple focal demyelinating lesions within the central nervous system (CNS). These lesions mainly consist of phagocytes that play a key role in lesion progression and remyelination, and therefore represent a promising therapeutic target in MS. We recently showed that unsaturated fatty acids produced by stearoyl-CoA desaturase-1 induce inflammatory foam cell formation during demyelination. These fatty acids are elongated by the "elongation of very long chain fatty acids" proteins (ELOVLs), generating a series of functionally distinct lipids. Here, we show that the expression and activity of ELOVLs are altered in myelin-induced foam cells. Especially ELOVL6, an enzyme responsible for converting saturated and monounsaturated C16 fatty acids into C18 species, was found to be up-regulated in myelin phagocytosing phagocytes in vitro and in MS lesions. Depletion of Elovl6 induced a repair-promoting phagocyte phenotype through activation of the S1P/PPARγ pathway. Elovl6-deficient foamy macrophages showed enhanced ABCA1-mediated lipid efflux, increased production of neurotrophic factors, and reduced expression of inflammatory mediators. Moreover, our data show that ELOVL6 hampers CNS repair, as Elovl6 deficiency prevented demyelination and boosted remyelination in organotypic brain slice cultures and the mouse cuprizone model. These findings indicate that targeting ELOVL6 activity may be an effective strategy to stimulate CNS repair in MS and other neurodegenerative diseases.

miR-128-3p inhibits intramuscular adipocytes differentiation in chickens by downregulating FDPS.

BACKGROUND: Intramuscular fat (IMF) content is the major indicator for evaluating chicken meat quality due to its positive correlation with tenderness, juiciness, and flavor. An increasing number of studies are focusing on the functions of microRNAs (miRNAs) in intramuscular adipocyte differentiation. However, little is known about the association of miR-128-3p with intramuscular adipocyte differentiation. Our previous RNA-seq results indicated that miR-128-3p was differentially expressed at different periods in chicken intramuscular adipocytes, revealing a possible association with intramuscular adipogenesis. The purpose of this research was to investigate the biological functions and regulatory mechanism of miR-128-3p in chicken intramuscular adipogenesis. RESULTS: The results of a series of assays confirmed that miR-128-3p could promote the proliferation and inhibit the differentiation of intramuscular adipocytes. A total of 223 and 1,050 differentially expressed genes (DEGs) were identified in the mimic treatment group and inhibitor treatment group, respectively, compared with the control group. Functional enrichment analysis revealed that the DEGs were involved in lipid metabolism-related pathways, such as the MAPK and TGF-ß signaling pathways. Furthermore, target gene prediction analysis showed that miR-128-3p can target many of the DEGs, such as FDPS, GGT5, TMEM37, and ASL2. The luciferase assay results showed that miR-128-3p targeted the 3' UTR of FDPS. The results of subsequent functional assays demonstrated that miR-128-3p acted as an inhibitor of intramuscular adipocyte differentiation by targeting FDPS. CONCLUSION: miR-128-3p inhibits chicken intramuscular adipocyte differentiation by downregulating FDPS. Our findings provide a theoretical basis for the study of lipid metabolism and reveal a potential target for molecular breeding to improve meat quality.

Isolation, Culture, and Adipogenic Induction of Stromal Vascular Fraction-derived Preadipocytes from Mouse Periaortic Adipose Tissue.

Perivascular adipose tissue (PVAT) is an adipose tissue depot that surrounds blood vessels and exhibits the phenotypes of white, beige, and brown adipocytes. Recent discoveries have shed light on the central role of PVAT in regulating vascular homeostasis and participating in the pathogenesis of cardiovascular diseases. A comprehensive understanding of PVAT properties and regulation is of great importance for the development of future therapies. Primary cultures of periaortic adipocytes are valuable for studying PVAT function and the crosstalk between periaortic adipocytes and vascular cells. This paper presents an economical and feasible protocol for the isolation, culture, and adipogenic induction of stromal vascular fraction-derived preadipocytes from mouse periaortic adipose tissue, which can be useful for modeling adipogenesis or lipogenesis in vitro. The protocol outlines tissue processing and cell differentiation for culturing periaortic adipocytes from young mice. This protocol will provide the technological cornerstone at the bench side for the investigation of PVAT function.

Transcriptome profiling of differentiating adipose-derived stem cells across species reveals new genes regulating adipogenesis.

Adipose-derived stem cells (ADSCs) that are enriched in adipose tissue with multilineage differentiation potential have become an important tool in therapeutic research and tissue engineering. Certain breeds of sheep exhibit a unique fat tail trait such that tail tissue accounts for approximately 10 % of body weight and can provide an excellent source of ADSCs. Here, we describe isolation of primary ADSCs from ovine embryonic fat tail tissues that displayed high self-renewal capacity, multilineage differentiation and excellent adipogenic ability. Through transcriptome analysis covering ADSCs differentiating into adipocytes, 37 transcription factors were involved in early transcriptional events that initiate a regulatory cascade of adipogenesis; the entire adipogenic activity consists of a reduction in proliferation ability and upregulation of genes related to lipid generation and energy metabolism, as well as several genes associated with myogenesis. Furthermore, Comparative transcriptome analysis across species (sheep, human, and mouse) revealed enhanced basal metabolic ability in differentiating ovine ADSCs, which may relate to the excellent adipogenic capability of these cells. We also identified a small evolutionarily conserved gene set, consisting of 21 and 22 genes exhibiting increased and decreased expression, respectively. Almost half (20) of these genes have not previously been reported to regulate adipogenesis in mammals. In this study, we identified important regulators that trigger ovine adipocyte differentiation, main biological pathways involved in adipogenesis as well as the evolutionarily conserved genes governing adipogenic process across species. Our study provides a novel excellent biomaterial and novel genes regulating adipogenesis for cellular transplantation therapy and investigations of fat metabolism.

Acetyl-coenzyme A acetyltransferase 1 promotes brown adipogenesis by activating the AMPK-PGC1α signaling pathway.

Brown adipose tissue (BAT) is thermogenic, expressing high levels of uncoupling protein-1 to convert nutrient energy to heat energy, bypassing ATP synthesis. BAT is a promising therapeutic target for treatment of obesity and type 2 diabetes since it converts fatty acids into heat but mechanisms controlling brown adipogenesis remain unclear. Knockdown of acetyl-Coenzyme A acetyltransferase 1 (ACAT1) in C3H10T1/2 cells suppressed brown adipocyte maturation during the current study and ACAT1 overexpression promoted brown adipocyte maturation. The downstream target of AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor gamma coactivator-1-α (PGC1α), was involved in the action of ACAT1 on brown adipocyte maturation. ACAT1 overexpression enhanced AMPK phosphorylation and promoted PGC1α expression. It is suggested that ACAT1 promotes brown adipocyte maturation by activating the AMPK-PGC1α signaling pathway.

miR-125a-3p regulates the expression of FSTL1, a pro-inflammatory factor, during adipogenic differentiation, and inhibits adipogenesis in mice.

Adipogenesis is tightly regulated by various factors, including genes and microRNAs. Excessive fat deposition is the key feature of obesity, which is a low-grade chronic inflammatory disease. Follistatin-like 1 (FSTL1) has been reported to be an important mediator involved in various inflammatory diseases. However, the underlying mechanism of FSTL1 in preadipocyte differentiation and inflammatory response is still unclear. The current study was designed to explore the biological function and potential mechanism of FSTL1 in mouse subcutaneous preadipocyte differentiation. We found that FSTL1 was highly expressed in the early stage of differentiation and subsequently decreased sharply, suggesting that FSTL1 played a possible role in adipogenesis. Meanwhile, the gain- and loss-of-function assays showed that FSTL1 was not only involved in the inflammatory response by inducing the expression of pro-inflammatory factors IL-1ß and CCL2 but also significantly attenuated preadipocyte differentiation, as evidenced by the reduction of lipid accumulation and the levels of adipogenic genes, including PPARγ and FABP4. In addition, the target gene prediction and luciferase reporter assay validated that miR-125a-3p targeted the 3' UTR region of FSTL1. These results demonstrated that miR-125a-3p negatively regulated the expression of FSTL1 at the mRNA and protein levels. Furthermore, overexpressing miR-125a-3p in preadipocytes dramatically accelerated adipogenic differentiation and downregulated the levels of IL-1ß and CCL2, which were in accordance with the knockdown of FSTL1. On the contrary, treatment with miR-125a-3p inhibitors attenuated adipogenesis but induced the expression of inflammatory genes. In summary, this study suggests a positive function of FSTL1 in adipocyte-induced inflammation and negatively regulates preadipocyte differentiation. Further studies demonstrated that miR-125a-3p could reverse the effect by targeting FSTL1, which might provide a better understanding of treating obesity-related inflammatory diseases.

Bta-miR-484 Targets SFRP1 and Affects Preadipocytes Proliferation, Differentiation, and Apoptosis.

MicroRNAs (miRNAs) are essential regulators of numerous biological processes in animals, including adipogenesis. Despite the abundance of miRNAs associated with adipogenesis, their exact mechanisms of action remain largely unknown. Our study highlights the role of bta-miR-484 as a major regulator of adipocyte proliferation, apoptosis, and differentiation. Here, we demonstrated that the expression of bta-miR-484 initially increased during adipogenesis before decreasing. Overexpression of bta-miR-484 in adipocytes ultimately inhibited cell proliferation and differentiation, reduced the number of EdU fluorescence-stained cells, increased the number of G1 phase cells, reduced the number of G2 and S phase cells, and downregulated the expression of proliferation markers (CDK2 and PCNA) and differentiation markers (CEBPA, FABP4, and LPL). Additionally, overexpression of bta-miR-484 promoted the expression of apoptosis-related genes (Caspase 3, Caspase 9, and BAX), and increased the number of apoptotic cells observed via flow cytometry. In contrast, bta-miR-484 inhibition in adipocytes yielded opposite effects to those observed during bta-miR-484 overexpression. Moreover, luciferase reporter assays confirmed SFRP1 as a target gene of bta-miR-484, and revealed that bta-miR-484 downregulates SFRP1 mRNA expression. These findings offer compelling evidence that bta-miR-484 targets SFRP1, inhibits proliferation and differentiation, and promotes apoptosis. Therefore, these results offer novel insights into the bta-miR-484 regulation of adipocyte growth and development.

Distinct response of adipocyte progenitors to glucocorticoids determines visceral obesity via the TEAD1-miR-27b-PRDM16 axis.

OBJECTIVE: Visceral obesity contributes to obesity-related complications; however, the intrinsic mechanism of depot-specific adipose tissue behavior remains unclear. Despite the pro-adipogenesis role of glucocorticoids (GCs) in adipogenesis, the role of GCs in visceral adiposity rather than in subcutaneous adipose tissue is not established. Because adipocyte progenitors display a striking depot-specific pattern, the regulatory pathways of novel progenitor subtypes within different depots remain unclear. This study describes a cell-specific mechanism underlying visceral adiposity. METHODS: A diverse panel of novel depot-specific adipose progenitors was screened in mice and human samples. The transcriptome distinction and various responses of novel progenitor subtypes of GCs were further measured using the GC receptor-chromatin immunoprecipitation assay and RNA sequencing. The mechanism of novel subtypes was identified using transposase-accessible chromatin analysis and bisulfite sequencing and further confirmed using precise editing of CpG methylation. RESULTS: Platelet-derived growth factor receptor α (PDGFRα+ ) progenitors, which were dominant in the visceral adipose tissue, were GC-sensitive beige adipose progenitors, whereas CD137+ progenitors, which were dominant in the subcutaneous adipose tissue, were GC-passive beige adipose progenitors. Expression of miR-27b, an inhibitor of adipocyte browning, was significantly increased in PDGFRα+ progenitors treated with GCs. Using transposase-accessible chromatin analysis, bisulfite sequencing, and precise editing of CpG methylation, TEA domain transcription factor 1 (TEAD1) was discovered to be uniquely hypomethylated in PDGFRα+ progenitors. CONCLUSIONS: GCs inhibited the PDGFRα+ progenitors' browning process via miR-27b, which was transcriptionally activated by the collaboration of TEAD1 with the GC receptor. These data provide insights into the mechanism of depot-specific variations in high-fat diet-induced obesity.

TMT-based quantitative proteomic analysis revealed that FBLN2 and NPR3 are involved in the early osteogenic differentiation of mesenchymal stem cells (MSCs).

The delicate equilibrium between osteoblast and adipocyte differentiation of MSCs is highly regulated. We screened for early-stage osteogenesis- or adipogenesis-based MSCs protein expression profiles using TMT-based quantitative proteomic analysis to identify novel participating molecules. Protein annotation, hierarchical clustering, functional stratification, and protein-protein association assessments were performed. Moreover, two upregulated proteins, namely, FBLN2 and NPR3, were validated to participate in the osteogenic differentiation process of MSCs. After that, we independently downregulated FBLN2 and NPR3 over seven days of osteogenic differentiation, and we performed quantitative proteomics analysis to determine how different proteins were regulated in knockdown vs. control cells. Based on gene ontology (GO) and network analyses, FBLN2 deficiency induced functional alterations associated with biological regulation and stimulus-response, whereas NPR3 deficiency induced functional alterations related to cellular and metabolic processes, and so on. These findings suggested that proteomics remains a useful method for an in-depth study of the MSCs differentiation process. This will assist in comprehensively evaluating its role in osteoporosis and provide additional approaches for identifying as-yet-unidentified effector molecules.

Kinetics of skeletal muscle regeneration after mild and severe muscle damage induced by electrically-evoked lengthening contractions.

Post-injury skeletal muscle regeneration requires interactions between myogenic and non-myogenic cells. Our knowledge on the regeneration process is mainly based on models using toxic, chemical, or physical (e.g., based on either muscle freezing or crushing) injury. Strikingly, the time course and magnitude of changes in the number of cells involved in muscle regeneration have been poorly described in relation to mild and severe muscle damage induced by electrically-evoked lengthening contractions. We investigated for the first time the kinetics and magnitude of changes in mononuclear cells in relation to the extent of muscle damage. Mild and severe injury were induced in vivo in the mouse gastrocnemius muscle by 1 and 30 electrically-evoked lengthening contractions, respectively. Several days after muscle damage, functional analysis of maximal torque production and histological investigations were performed to assess the related cellular changes. Torque recovery was faster after mild injury than after severe muscle damage. More necrotic and regenerating myofibers were observed after severe muscle damage as compared with mild injury, illustrating an association between functional and histological alterations. The kinetics of changes in muscle stem cells (total, proliferating, and differentiating), endothelial cells, fibro-adipogenic progenitors (FAPs), and macrophages in the regenerating muscle was similar in mild and severe models. However, the magnitude of changes in the number of differentiating muscle stem cells, hematopoietic cells, among which macrophages, and FAPs was higher in severe muscle damage. Collectively, our results show that the amount of myogenic and non-myogenic cells varies according to the extent of skeletal muscle injury to ensure efficient skeletal muscle regeneration while the kinetics of changes is independent of muscle tissue alterations. The possibility to experimentally modulate the extent of muscle damage will be useful to further investigate the cellular and molecular events involved in muscle regeneration.

Kaempferol: A Dietary Flavonol in Alleviating Obesity.

Obesity is considered as a chronic and high-prevalence disease on a global scale which affects all genders and ages. Although various drugs have been confirmed for the treatment of obesity, these medications have been shown to have a number of adverse effects on health. It is highlighted that natural products have an alleviative role in a broad spectrum of diseases, in particular obesity, and diabetes. Kaempferol (KMP), a plant- derived flavonol, is considerably engaged in the suppression of oxidative stress, radical scavenging, opposing cellular toxicity, and induction of the production and release of growth factors. This flavonol combats obesity by suppressing adipogenesis, regulating lipid and glucose metabolism, changing gut microbiota, and activating autophagy. Also, studies have shown that KMP exerts its anti-obesity actions by decreasing the accumulation of lipids and triglycerides (TGs), increasing fatty acid oxidation, and regulating multiple metabolic genes in the adipocytes. Considering that KMP may be a potential candidate for combating obesity, this paper summarizes the possible therapeutic roles of KMP in the treatment and prevention of this disease.

The negative adipogenesis regulator Dlk1 is transcriptionally regulated by Ifrd1 (TIS7) and translationally by its orthologue Ifrd2 (SKMc15).

Delta-like homolog 1 (Dlk1), an inhibitor of adipogenesis, controls the cell fate of adipocyte progenitors. Experimental data presented here identify two independent regulatory mechanisms, transcriptional and translational, by which Ifrd1 (TIS7) and its orthologue Ifrd2 (SKMc15) regulate Dlk1 levels. Mice deficient in both Ifrd1 and Ifrd2 (dKO) had severely reduced adipose tissue and were resistant to high-fat diet-induced obesity. Wnt signaling, a negative regulator of adipocyte differentiation, was significantly upregulated in dKO mice. Elevated levels of the Wnt/ß-catenin target protein Dlk1 inhibited the expression of adipogenesis regulators Pparg and Cebpa, and fatty acid transporter Cd36. Although both Ifrd1 and Ifrd2 contributed to this phenotype, they utilized two different mechanisms. Ifrd1 acted by controlling Wnt signaling and thereby transcriptional regulation of Dlk1. On the other hand, distinctive experimental evidence showed that Ifrd2 acts as a general translational inhibitor significantly affecting Dlk1 protein levels. Novel mechanisms of Dlk1 regulation in adipocyte differentiation involving Ifrd1 and Ifrd2 are based on experimental data presented here.

A defect in mitochondrial fatty acid synthesis impairs iron metabolism and causes elevated ceramide levels.

In most eukaryotic cells, fatty acid synthesis (FAS) occurs in the cytoplasm and in mitochondria. However, the relative contribution of mitochondrial FAS (mtFAS) to the cellular lipidome is not well defined. Here we show that loss of function of Drosophila mitochondrial enoyl coenzyme A reductase (Mecr), which is the enzyme required for the last step of mtFAS, causes lethality, while neuronal loss of Mecr leads to progressive neurodegeneration. We observe a defect in Fe-S cluster biogenesis and increased iron levels in flies lacking mecr, leading to elevated ceramide levels. Reducing the levels of either iron or ceramide suppresses the neurodegenerative phenotypes, indicating an interplay between ceramide and iron metabolism. Mutations in human MECR cause pediatric-onset neurodegeneration, and we show that human-derived fibroblasts display similar elevated ceramide levels and impaired iron homeostasis. In summary, this study identifies a role of mecr/MECR in ceramide and iron metabolism, providing a mechanistic link between mtFAS and neurodegeneration.