HES1 inhibits adipogenesis of porcine mesenchymal stem cells via transcriptional repression of FAD24

NOTCH Signaling Networks in Perivascular Adipose Tissue

Over a hundred years ago, mutants were detected in Drosophila melanogaster that led to a NOTCH in the wing tip. This original phenotype was reflected in the nomenclature of the gene family that was later cloned and characterized in the 1980s and found to be conserved across metazoans. NOTCH signaling relies on transmembrane ligands and receptors that require cellular contact for receptor activation, reflecting its role in multicellular organisms as an intercellular signaling strategy. In humans, mutations in genes encoding NOTCH and their ligands have been shown to promote human disease; these aspects have been extensively reviewed. Notch signaling plays important roles in vascular development (vasculogenesis and angiogenesis) and homeostasis. NOTCH signaling is also active in adipose tissue and contributes to adipocyte differentiation. In addition, NOTCH activity regulates functions of other metabolic organs. This review focuses on NOTCH activity in perivascular adipose tissue within the vascular microenvironment as defined by mouse studies and summarizes expression and potential signaling of the NOTCH signaling network in human perivascular adipose tissue. Due to the strong activity of NOTCH in regulation of metabolic function, activation of the NOTCH network in specific cell types in perivascular adipose tissue has implications for signaling to the underlying blood vessel and control of vascular health and disease.

NOTCH1 as a Negative Regulator of Avian Adipocyte Differentiation: Implications for Fat Deposition

The NOTCH signaling pathway plays a pivotal role in diverse developmental processes, including cell proliferation and differentiation. In this study, we investigated whether this signaling molecules also contribute to avian adipogenesis. Using previous mRNA-seq datasets, we examined the expression of 11 signaling members during avian adipocyte differentiation. We found most members are down-regulated throughout differentiation (p < 0.05). As a representative, NOTCH1 was decreased in cultured chicken abdominal adipocytes during adipogenesis at mRNA and protein levels (p < 0.05). Moreover, using an overexpression plasmid for NOTCH1's intracellular domain (NICD1), as well as siRNA and DAPT to activate or deplete NOTCH1 in cells, we investigated the role of NOTCH1 in avian adipogenesis. Our findings illuminate that NOTCH1 activates the expression of HES1 and SOCS3 while it decreases NR2F2 and NUMB (p < 0.05), as well as inhibits oleic acid-induced adipocyte differentiation (p < 0.01). We further demonstrate that HES1, a downstream transcription factor activated by NOTCH1, also significantly inhibits adipogenesis by suppressing PPARγ and C/EBPα (p < 0.01). Collectively, these findings establish NOTCH1 as a negative regulator of avian adipocyte differentiation, unveiling NOTCH signaling as a potential target for regulating avian fat deposition.

A Wrong Fate Decision in Adipose Stem Cells upon Obesity

Progress has been made in identifying stem cell aging as a pathological manifestation of a variety of diseases, including obesity. Adipose stem cells (ASCs) play a core role in adipocyte turnover, which maintains tissue homeostasis. Given aberrant lineage determination as a feature of stem cell aging, failure in adipogenesis is a culprit of adipose hypertrophy, resulting in adiposopathy and related complications. In this review, we elucidate how ASC fails in entering adipogenic lineage, with a specific focus on extracellular signaling pathways, epigenetic drift, metabolic reprogramming, and mechanical stretch. Nonetheless, such detrimental alternations can be reversed by guiding ASCs towards adipogenesis. Considering the pathological role of ASC aging in obesity, targeting adipogenesis as an anti-obesity treatment will be a key area of future research, and a strategy to rejuvenate tissue stem cell will be capable of alleviating metabolic syndrome.

Functional heterogeneity of immune defenses in molluscan oysters Crassostrea hongkongensis revealed by high-throughput single-cell transcriptome

Oyster is the worldwide aquaculture molluscan and evolves a complex immune defense system, with hemocytes as the major immune system for its host defense. However, the functional heterogeneity of hemocyte has not been characterized, which markedly hinders our understanding of its defense role. Here, we used the single-cell transcriptome profiling (scRNA-seq), which provides a high-resolution visual insight into its dynamics, to map the hemocyte and assess its heterogeneity in a molluscan oyster Crassostrea hongkongensis. By combining with the cell type specific RNA-seq, thirteen subpopulations belonging to granulocyte, semi-granulocyte, and hyalinocyte were revealed. The granulocytes mainly participated in immune response and autophagy process. Pseudo-temporal ordering of granulocytes identified two different cell-lineages. The hematopoietic transcription factors regulated networks controlling their differentiations were also identified. We further identified one subpopulation of granulocytes in immune activate states with the cell cycle and immune responsive genes expressions, which illustrated the functional heterogeneity of the same cell type. Collectively, our scRNA-seq analysis demonstrated the hemocytes diversity of molluscans. The results are important in our understanding of the immune defense evolution and functional differentiation of hemocytes in Phylum Mollusca.

Ziziphus spina-christi (L.) fortified with Camellia sinensis mediates apoptosis, Notch-1 signaling, and mitigates obesity-induced non-alcoholic fatty liver

The habit of drinking tea is highly prevalent and could be utilized to introduce more health benefits through fortification with medicinal plants. The purpose of this analysis was to assess the nutritional quality and health benefits of fortified Ziziphus tea (ZT) with green tea (GT) against obesity and non-alcoholic fatty liver disease (NAFLD). Proximate analysis and sensory evaluation were carried out on the fortified tea. In the in vivo study, 15 SD rats were used for each group. Flow cytometry was utilized for caspase 3 analysis. ELISA was used for the detection of tumor necrosis factor-alpha and adiponectin levels. Real-time PCR was used to detect Notch-1 and Hes-1 gene expression. The composition of fortified (GT+ZT) showed a significant improvement in the nutritional value represented by the increase in overall protein, crude fat, crude fiber, ash, carbohydrate, mineral contents, and antioxidant capacity. Treatment with GT+ZT restored the disturbance in body weight, lipid profile, liver function, glucose, insulin sensitivity index, and oxidative status. It reversed the changes in TNF-α and adiponectin levels. Their protective effects against NAFLD were indicated by the inhibition of hepatic caspase-3 activity, suppression of Notch-1, and Hes-1 gene expression and amelioration of high-fat diet (HFD)-induced histological alterations. Collectively, our findings, elucidate the precise mechanism of fortified ZT+GT for the attenuation of obesity-induced metabolic disorders and NAFLD via regulating lipolysis, TNF-α, adiponectin, apoptosis, and Notch-1 signaling pathways, and provide a foundation for an easily implemented healthy habit of drinking. PRACTICAL APPLICATIONS: The incorporation of bioactive compounds into functional foods is a growing market. Consumer attention in well-being has increased rapidly toward a fortified diet that provides additional health effects. The fortified (GT+ZT) tea may potentially serve as an easily implemented healthy drinking habit to prevent and manage obesity and NAFLD and reduce the risk of other diseases. Fortification with ZT improved the health-promoting functionality of GT through the enhancement of total protein, carbohydrates, antioxidant, and mineral contents. This was reflected by their synergetic therapeutic activity in ameliorating the disturbance in obesity-related disorders and NAFLD via regulating lipolysis, inflammation, oxidative stress, apoptosis, and Notch-1 signaling pathways. Therefore, (GT+ZT) could be considered functional foods which attribute to functional improvement and reduction in disease risk.

hPER3 promotes adipogenesis via hHSP90AA1-mediated inhibition of Notch1 pathway

The period circadian regulator 3 (PER3) has been reported to play a negative role in human immortalized bone marrow-derived Scp-1 cells (iBMSCs) and patient adipose-derived stromal cells (PASCs) or a negative/positive role in mice adipogenesis. However, human PER3 (hPER3) was identified as a positive regulator of human adipose tissue-derived stromal cells (hADSCs) adipogenesis in this study. Silencing or overexpression of hPER3 in hADSCs inhibited and promoted adipogenesis in vitro. In vivo, the overexpression of hPER3 increased high-fat diet-induced inguinal white adipose tissue (iWAT) and epididymal white adipose tissue (eWAT) forms, increasing systemic glucose intolerance and insulin resistance. Molecularly, hPER3 does not interact with hPPARγ, but represses Notch1 signaling pathway to enhance adipogenesis by interacting with hHSP90AA1, which is able to combine with the promoter of hNotch1 and inactivate its expression. Thus, our study revealed hPER3 as a critical positive regulator of hADSCs adipogenesis, which was different from the other types of cells, providing a critical role of it in treating obesity.

Deconstructing transcriptional variations and their effects on immunomodulatory function among human mesenchymal stromal cells

Background

Mesenchymal stromal cell (MSC)-based therapies are being actively investigated in various inflammatory disorders. However, functional variability among MSCs cultured in vitro will lead to distinct therapeutic efficacies. Until now, the mechanisms behind immunomodulatory functional variability in MSCs are still unclear.

Methods

We systemically investigated transcriptomic variations among MSC samples derived from multiple tissues to reveal their effects on immunomodulatory functions of MSCs. We then analyzed transcriptomic changes of MSCs licensed with INFγ to identify potential molecular mechanisms that result in distinct MSC samples with different immunomodulatory potency.

Results

MSCs were clustered into distinct groups showing different functional enrichment according to transcriptomic patterns. Differential expression analysis indicated that different groups of MSCs deploy common regulation networks in response to inflammatory stimulation, while expression variation of genes in the networks could lead to different immunosuppressive capability. These different responsive genes also showed high expression variability among unlicensed MSC samples. Finally, a gene panel was derived from these different responsive genes and was able to regroup unlicensed MSCs with different immunosuppressive potencies.

Conclusion

This study revealed genes with expression variation that contribute to immunomodulatory functional variability of MSCs and provided us a strategy to identify candidate markers for functional variability assessment of MSCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-020-02121-8.

The Role of Pref-1 during Adipogenic Differentiation: An Overview of Suggested Mechanisms

Obesity contributes significantly to the global health burden. A better understanding of adipogenesis, the process of fat formation, may lead to the discovery of novel treatment strategies. However, it is of concern that the regulation of adipocyte differentiation has predominantly been studied using the murine 3T3-L1 preadipocyte cell line and murine experimental animal models. Translation of these findings to the human setting requires confirmation using experimental models of human origin. The ability of mesenchymal stromal/stem cells (MSCs) to differentiate into adipocytes is an attractive model to study adipogenesis in vitro. Differences in the ability of MSCs isolated from different sources to undergo adipogenic differentiation, may be useful in investigating elements responsible for regulating adipogenic differentiation potential. Genes involved may be divided into three broad categories: early, intermediate and late-stage regulators. Preadipocyte factor-1 (Pref-1) is an early negative regulator of adipogenic differentiation. In this review, we briefly discuss the adipogenic differentiation potential of MSCs derived from two different sources, namely adipose-derived stromal/stem cells (ASCs) and Wharton’s Jelly derived stromal/stem cells (WJSCs). We then discuss the function and suggested mechanisms of action of Pref-1 in regulating adipogenesis, as well as current findings regarding Pref-1’s role in human adipogenesis.

Suppression of Notch Signaling Stimulates Progesterone Synthesis by Enhancing the Expression of NR5A2 and NR2F2 in Porcine Granulosa Cells

The conserved Notch pathway is reported to be involved in progesterone synthesis and secretion; however, the exact effects remain controversial. To determine the role and potential mechanisms of the Notch signaling pathway in progesterone biosynthesis in porcine granulosa cells (pGCs), we first used a pharmacological γ-secretase inhibitor, N-(N-(3,5-difluorophenacetyl-l-alanyl))-S-phenylglycine t-butyl ester (DAPT), to block the Notch pathway in cultured pGCs and then evaluated the expression of genes in the progesterone biosynthesis pathway and key transcription factors (TFs) regulating steroidogenesis. We found that DAPT dose- and time-dependently increased progesterone secretion. The expression of steroidogenic proteins NPC1 and StAR and two TFs, NR5A2 and NR2F2, was significantly upregulated, while the expression of HSD3B was significantly downregulated. Furthermore, knockdown of both NR5A2 and NR2F2 with specific siRNAs blocked the upregulatory effects of DAPT on progesterone secretion and reversed the effects of DAPT on the expression of NPC1, StAR, and HSD3B. Moreover, knockdown of NR5A2 and NR2F2 stimulated the expression of Notch3. In conclusion, the inhibition of Notch signaling stimulated progesterone secretion by enhancing the expression of NPC1 and StAR, and the two TFs NR5A2 and NR2F2 acted as downstream TFs of Notch signaling in regulating progesterone synthesis.

Human NOC3 is essential for DNA replication licensing in human cells

Noc3p (Nucleolar Complex-associated protein) is an essential protein in budding yeast DNA replication licensing. Noc3p mediates the loading of Cdc6p and MCM proteins onto replication origins during the M-to-G₁ transition by interacting with ORC (Origin Recognition Complex) and MCM (Minichromosome Maintenance) proteins. FAD24 (Factor for Adipocyte Differentiation, clone number 24), the human homolog of Noc3p (hNOC3), was previously reported to play roles in the regulation of DNA replication and proliferation in human cells. However, the role of hNOC3 in replication licensing was unclear. Here we report that hNOC3 physically interacts with multiple human pre-replicative complex (pre-RC) proteins and associates with known replication origins throughout the cell cycle. Moreover, knockdown of hNOC3 in HeLa cells abrogates the chromatin association of other pre-RC proteins including hCDC6 and hMCM, leading to DNA replication defects and eventual apoptosis in an abortive S-phase. In comparison, specific inhibition of the ribosome biogenesis pathway by preventing pre-rRNA synthesis, does not lead to any cell cycle or DNA replication defect or apoptosis in the same timeframe as the hNOC3 knockdown experiments. Our findings strongly suggest that hNOC3 plays an essential role in pre-RC formation and the initiation of DNA replication independent of its potential role in ribosome biogenesis in human cells.

Curcumin suppresses Notch‑1 signaling: Improvements in fatty liver and insulin resistance in rats

Curcumin is a well‑known phenolic substance and has many pharmacological effects associated with metabolism. However, the exact molecular mechanisms underlying this process have yet to be determined. The Notch pathway is a signal transduction pathway involved in energy metabolism. The present study aimed to investigate the effects of curcumin administration on glucose‑lipid metabolism in rats subjected to a high fat diet, and investigate changes in Notch‑1 signaling. Sprague‑Dawley rats (n=40) were randomly divided into four groups (10 rats/group): Control diet group, high fat diet group, high fat diet plus curcumin low dose group and high fat diet plus curcumin high dose group. Following 8 weeks of treatment with curcumin (100 mg/kg in the low dose group and 200 mg/kg in the high dose group), serum metabolic markers and hepatic gene expression patterns were investigated. No differences in body weight following 8 weeks of curcumin administration (P>0.05) were observed; however, curcumin treatment did reduce visceral fat levels (peri‑epididymal and peri‑renal), and decreased cholesterol, triglyceride and low‑density lipoprotein levels in serum compared with the high fat diet rats that did not receive curcumin (P<0.05, P<0.01). An oral glucose tolerance test and an intraperitoneal insulin tolerance test revealed that insulin resistance was reduced (P<0.05 or P<0.01) and tissue section analysis revealed that hepatosteatosis was attenuated following treatment with curcumin. Furthermore, the protein expression of Notch‑1 and its downstream target Hes‑1 were suppressed. These effects were also in parallel with an upregulation of fatty acid oxidation‑associated gene expression, including peroxisome proliferator‑activated receptor (PPAR)‑α, carnitine palmitoyltransferase 1 and PPAR‑γ (P<0.05). In addition, curcumin administration led to a downregulation in the expression of lipogenic genes, including sterol regulatory element‑binding protein, fatty acid synthase and acetyl‑CoA carboxylase (P<0.05). The expression of inflammation‑associated genes, including nuclear factor‑κB, tumor necrosis factor‑α and prostaglandin‑endoperoxide synthase 2 were also suppressed. The results of the present study suggest that the hepatic Notch‑1 pathway can be suppressed via curcumin treatment, which may ameliorate fatty liver and insulin resistance in rats subjected to a high fat diet.

Notch Represses Transcription by PRC2 Recruitment to the Ternary Complex

It is well established that Notch functions as a transcriptional activator through the formation of a ternary complex that comprises Notch, Maml, and CSL. This ternary complex then serves to recruit additional transcriptional cofactors that link to higher order transcriptional complexes. The mechanistic details of these events remain unclear. This report reveals that the Notch ternary complex can direct the formation of a repressor complex to terminate gene expression of select target genes. Herein, it is demonstrated that p19^Arf and Klf4 are transcriptionally repressed in a Notch-dependent manner. Furthermore, results indicate that Notch recruits Polycomb Repressor Complex 2 (PRC2) and Lysine Demethylase 1 (KDM1A/LSD1) to these promoters, which leads to changes in the epigenetic landscape and repression of transcription. The demethylase activity of LSD1 is a prerequisite for Notch-mediated transcriptional repression. In addition, a stable Notch transcriptional repressor complex was identified containing LSD1, PRC2, and the Notch ternary complex. These findings demonstrate a novel function of Notch and provide further insight into the mechanisms of Notch-mediated tumorigenesis.Implications: This study provides rationale for the targeting of epigenetic enzymes to inhibit Notch activity or use in combinatorial therapy to provide a more profound therapeutic response. Mol Cancer Res; 15(9); 1173-83. ©2017 AACR.

Roles of Notch Signaling in Adipocyte Progenitor Cells and Mature Adipocytes

Adipose tissues, composed with mature adipocytes and preadipocytic stromal/stem cells, play crucial roles in whole body energy metabolism and regenerative medicine. Mature adipocytes are derived and differentiated from mesenchymal stem cells (MSCs) or preadipocytes. This differentiation process, also called adipogenesis, is regulated by several signaling pathways and transcription factors. Notch1 signaling is a highly conserved pathway that is indispensable for stem cell hemostasis and tissue development. In adipocyte progenitor cells, Notch1 signaling regulates the adipogenesis process including proliferation and differentiation of the adipocyte progenitor cells in vitro. Notably, the roles of Notch1 signaling in beige adipocytes formation, adipose development, and function, and the whole body energy metabolism have been recently reported. Here, we mainly review and discuss the roles of Notch1 signaling in adipogenesis in vitro as well as in beige adipocytes formation, adipocytes dedifferentiation, and function in vivo. J. Cell. Physiol. 232: 1258-1261, 2017. © 2016 Wiley Periodicals, Inc.

Original Research: Hydroxytyrosol, an ingredient of olive oil, reduces triglyceride accumulation and promotes lipolysis in human primary visceral adipocytes during differentiation

Hydroxytyrosol has various pharmacological properties, including anti-oxidative stress and anti-inflammatory activities, preventing hyperglycemia, insulin resistance, and the metabolic syndrome. The present study is focused on the anti-adipogenic and lipolytic activity of hydroxytyrosol on primary human visceral adipocytes. Pre-adipocytes were analyzed after 10 (P10) and 20 (P20) days of treatment during differentiation and after 7 (A7) days of treatment when they reached mature shape. The treatment with hydroxytyrosol extract significantly (P < 0.001) increased apoptosis in P10 and P20 cells in comparison to control and A7 cells; significantly (P < 0.001) reduced triglyceride accumulation in P20 cells compared to P10 and control cells; and significantly (P < 0.001) increased lipolysis in P20 cells in comparison to control cells and A7 mature adipocytes. Hydroxytyrosol-treated P20 cells significantly (P < 0.05) increased expression of genes involved in inhibition of adipogenesis, such as GATA2, GATA3, WNT3A, SFRP5, HES1, and SIRT1. In contrast, genes involved in promoting adipogenesis such as LEP, FGF1, CCND1, and SREBF1 were significantly down-regulated by hydroxytyrosol treatment. These data suggest that hydroxytyrosol promotes lipolysis and apoptotic activity in primary human visceral pre-adipocytes during differentiation and does not affect already mature adipocytes.

Notch signaling pathway activation in normal and hyperglycemic rats differs in the stem cells of visceral and subcutaneous adipose tissue

The precise mechanisms underlying the differential function and cardiometabolic risk of white adipose tissue (WAT) remain unclear. Visceral adipose tissue (VWAT) and subcutaneous adipose tissue (SCWAT) have different metabolic functions that seem to be ascribed to their different intrinsic expansion capacities. Here we have hypothesized that the WAT characteristics are determined by the resident adipose-derived stem cells (ASCs) found in the different WAT depots. Therefore, our objective has been to investigate adipogenesis in anatomically distinct fat depots. ASCs from five different WAT depots were characterized in both healthy lean and diabetic obese rats, showing significant differences in expression of some of genes governing the stemness and the earlier adipogenic differentiation steps. Notch-target genes [Hes (hairy and enhancer of split) and Hey (hairy/enhancer of split related with YRPW motif) families] were upregulated in ASCs derived from visceral depots. Upon adipogenic differentiation, adipocyte cell markers were downregulated in ASCs from VWAT in comparison to ASCs from SCWAT, revealing a lower adipogenic capacity in ASCs of visceral origin than in those of SCWAT in accordance with the differential activation of Notch signaling. Notch upregulation by its activator phenethyl isothiocyanate attenuated the adipogenic differentiation of ASCs from SCWAT whereas Notch inhibition by N-[N-(3,5-difluorophenacetyl-L-alanyl)]-S-phenylglycine t-butyl ester (DAPT) increased the adipogenic differentiation of ASCs from visceral origin. In conclusion, the differential activation of Notch in ASCs is the origin of the different intrinsic WAT expansion capacities that contribute to the regional variations in WAT homeostasis and to its associated cardiometabolic risk.

miR-381 Regulates Neural Stem Cell Proliferation and Differentiation via Regulating Hes1 Expression

Neural stem cells are self-renewing, multipotent and undifferentiated precursors that retain the capacity for differentiation into both glial (astrocytes and oligodendrocytes) and neuronal lineages. Neural stem cells offer cell-based therapies for neurological disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease and spinal cord injuries. However, their cellular behavior is poorly understood. MicroRNAs (miRNAs) are a class of small noncoding RNAs involved in cell development, proliferation and differentiation through regulating gene expression at post-transcriptional level. The role of miR-381 in the development of neural stem cells remains unknown. In this study, we showed that overexpression of miR-381 promoted neural stem cells proliferation. It induced the neural stem cells differentiation to neurons and inhibited their differentiation to astrocytes. Furthermore, we identified HES1 as a direct target of miR-381 in neural stem cells. Moreover, re-expression of HES1 impaired miR-381-induced promotion of neural stem cells proliferation and induce neural stem cells differentiation to neurons. In conclusion, miR-381 played important role in neural stem cells proliferation and differentiation.

Human Mesenchymal Stem Cells Retain Multilineage Differentiation Capacity Including Neural Marker Expression after Extended In Vitro Expansion

The suitability of human mesenchymal stem cells (hMSCs) in regenerative medicine relies on retention of their proliferative expansion potential in conjunction with the ability to differentiate toward multiple lineages. Successful utilisation of these cells in clinical applications linked to tissue regeneration requires consideration of biomarker expression, time in culture and donor age, as well as their ability to differentiate towards mesenchymal (bone, cartilage, fat) or non-mesenchymal (e.g., neural) lineages. To identify potential therapeutic suitability we examined hMSCs after extended expansion including morphological changes, potency (stemness) and multilineage potential. Commercially available hMSC populations were expanded in vitro for > 20 passages, equating to > 60 days and > 50 population doublings. Distinct growth phases (A-C) were observed during serial passaging and cells were characterised for stemness and lineage markers at representative stages (Phase A: P+5, approximately 13 days in culture; Phase B: P+7, approximately 20 days in culture; and Phase C: P+13, approximately 43 days in culture). Cell surface markers, stem cell markers and lineage-specific markers were characterised by FACS, ICC and Q-PCR revealing MSCs maintained their multilineage potential, including neural lineages throughout expansion. Co-expression of multiple lineage markers along with continued CD45 expression in MSCs did not affect completion of osteogenic and adipogenic specification or the formation of neurospheres. Improved standardised isolation and characterisation of MSCs may facilitate the identification of biomarkers to improve therapeutic efficacy to ensure increased reproducibility and routine production of MSCs for therapeutic applications including neural repair.