CXCL3 positively regulates adipogenic differentiation

CXCL3: A key player in tumor microenvironment and inflammatory diseases

CXCL3 (C-X-C Motif Chemokine 3), a member of the C-X-C chemokine subfamily, operates as a potent chemoattractant for neutrophils, thereby orchestrating the recruitment and migration of leukocytes alongside eliciting an inflammatory response. Recent inquiries have shed light on the pivotal roles of CXCL3 in the context of carcinogenesis. In the tumor microenvironment, CXCL3 emanating from both tumor and stromal cells intricately modulates cellular behaviors through autocrine and paracrine actions, primarily via interaction with its receptor CXCR2. Activation of signaling cascades such as ERK/MAPK, AKT, and JAK2/STAT3 underscores CXCL3's propensity to favor tumorigenic processes. However, CXCL3 exhibits dualistic behaviors, as evidenced by its capacity to exert anti-tumor effects under specific conditions. Additionally, the involvement of CXCL3 extends to inflammatory disorders like eclampsia, obesity, and asthma. This review encapsulates the structural attributes, biological functionalities, and molecular underpinnings of CXCL3 across both tumorigenesis and inflammatory diseases.

The potency of mesenchymal stem/stromal cells: does donor sex matter?

Mesenchymal stem/stromal cells (MSCs) are a promising therapeutic tool in cell therapy and tissue engineering because of their multi-lineage differentiation capacity, immunomodulatory effects, and tissue protective potential. To achieve optimal results as a therapeutic tool, factors affecting MSC potency, including but not limited to cell source, donor age, and cell batch, have been investigated. Although the sex of the donor has been attributed as a potential factor that can influence MSC potency and efficacy, the impact of donor sex on MSC characteristics has not been carefully investigated. In this review, we summarize published studies demonstrating donor-sex-related MSC heterogeneity and emphasize the importance of disclosing donor sex as a key factor affecting MSC potency in cell therapy.

RNA-seq analysis reveals modulation of inflammatory pathways by an enriched-triterpene natural extract in mouse and human macrophage cell lines

Chronic inflammation is crucial in developing insulin resistance and type 2 diabetes. Previous studies have shown that a leaf extract of Eucalyptus tereticornis, with ursolic acid (UA), oleanolic acid (OA), and ursolic acid lactone (UAL) as the main molecules (78 %) mixed with unknown minor metabolites (22 %), provided superior anti-inflammatory, hypoglycemic, and hypolipidemic effects than reconstituted triterpenoid mixtures in macrophage cell lines and a pre-diabetic mouse model. Further identification of the molecular mechanisms of action of this mixture of triterpenes is required. This study aims to analyse the RNA expression profiles of mouse and human macrophage cell lines treated with the natural extract and its components. Activated macrophage cell lines were treated with the natural extract, UA, OA, UAL or a triterpene mixture (M1). RNA was extracted and sequenced using the DNBseq platform and the EnrichR software to perform gene enrichment analysis using the Gene Ontology database, Kyoto Encyclopedia of Genes and Genomes, and Reactome. To conduct clustering analysis, we standardised the normalised counts of each gene and applied k-means clustering. The combination of molecules in the natural extract has an additive or synergic effect that affects the expression of up-regulated genes by macrophage activation. Triterpenes (M1) regulated 76 % of human and 68 % of mouse genes, while uncharacterised minority molecules could regulate 24 % of human and 32 % of mouse genes. The extract inhibited the expression of many cytokines (IL6, IL1, OSM), chemokines (CXCL3), inflammatory mediators (MMP8 and MMP13) and the JAK-STAT signalling pathway in both models. The natural extract has a more powerful immunomodulatory effect than the triterpene mixture, increasing the number of genes regulated in mouse and human models. Our study shows that Eucalyptus tereticornis extract is a promising option for breaking the link between inflammation and insulin resistance.

CXCR2 chemokine receptor - a master regulator in cancer and physiology

Recent findings have modified our understanding of the roles of chemokine receptor CXCR2 and its ligands in cancer, inflammation, and immunity. Studies in Cxcr2 tissue-specific knockout mice show that this receptor is involved in, among other things, cancer, central nervous system (CNS) function, metabolism, reproduction, COVID-19, and the response to circadian cycles. Moreover, CXCR2 involvement in neutrophil function has been revisited not only in physiology but also for its major contribution to cancers. The recent unfolding of the role of CXCR2 in numerous cancers has led to extensive evaluation of multiple CXCR2 antagonists in preclinical and clinical studies. In this review we discuss the potential of targeting CXCR2 for cancer treatment.

CXCL13 promotes thermogenesis in mice via recruitment of M2 macrophage and inhibition of inflammation in brown adipose tissue

Introduction

Brown adipose tissue (BAT) is mainly responsible for mammalian non-shivering thermogenesis and promotes energy expenditure. Meanwhile, similar to white adipose tissue (WAT), BAT also secretes a variety of adipokines to regulate metabolism through paracrine, autocrine, or endocrine ways. The chemokine C-X-C motif chemokine ligand-13 (CXCL13), a canonical B cell chemokine, functions in inflammation and tumor-related diseases. However, the role of CXCL13 in the adipose tissues is unclear.

Methods

The expression of CXCL13 in BAT and subcutaneous white adipose tissue (SWAT) of mice under cold stimulation were detected. Local injection of CXCL13 into BAT of normal-diet and high-fat-diet induced obese mice was used to detect thermogenesis and determine cold tolerance. The brown adipocytes were treated with CXCL13 alone or in the presence of macrophages to determine the effects of CXCL13 on thermogenic and inflammation related genes expression in vitro.

Results

In this study, we discovered that the expression of CXCL13 in the stromal cells of brown adipose tissue significantly elevated under cold stimulation. Overexpression of CXCL13 in the BAT via local injection could increase energy expenditure and promote thermogenesis in obese mice. Mechanically, CXCL13 could promote thermogenesis via recruiting M2 macrophages in the BAT and, in the meantime, inhibiting pro-inflammatory factor TNFα level.

Discussion

This study revealed the novel role of adipose chemokine CXCL13 in the regulation of BAT activity and thermogenesis.

A single-cell atlas of bovine skeletal muscle reveals mechanisms regulating intramuscular adipogenesis and fibrogenesis

BACKGROUND

Intramuscular fat (IMF) and intramuscular connective tissue (IMC) are often seen in human myopathies and are central to beef quality. The mechanisms regulating their accumulation remain poorly understood. Here, we explored the possibility of using beef cattle as a novel model for mechanistic studies of intramuscular adipogenesis and fibrogenesis.

METHODS

Skeletal muscle single-cell RNAseq was performed on three cattle breeds, including Wagyu (high IMF), Brahman (abundant IMC but scarce IMF), and Wagyu/Brahman cross. Sophisticated bioinformatics analyses, including clustering analysis, gene set enrichment analyses, gene regulatory network construction, RNA velocity, pseudotime analysis, and cell-cell communication analysis, were performed to elucidate heterogeneities and differentiation processes of individual cell types and differences between cattle breeds. Experiments were conducted to validate the function and specificity of identified key regulatory and marker genes. Integrated analysis with multiple published human and non-human primate datasets was performed to identify common mechanisms.

RESULTS

A total of 32 708 cells and 21 clusters were identified, including fibro/adipogenic progenitor (FAP) and other resident and infiltrating cell types. We identified an endomysial adipogenic FAP subpopulation enriched for COL4A1 and CFD (log2FC = 3.19 and 1.92, respectively; P < 0.0001) and a perimysial fibrogenic FAP subpopulation enriched for COL1A1 and POSTN (log2FC = 1.83 and 0.87, respectively; P < 0.0001), both of which were likely derived from an unspecified subpopulation. Further analysis revealed more progressed adipogenic programming of Wagyu FAPs and more advanced fibrogenic programming of Brahman FAPs. Mechanistically, NAB2 drives CFD expression, which in turn promotes adipogenesis. CFD expression in FAPs of young cattle before the onset of intramuscular adipogenesis was predictive of IMF contents in adulthood (R2  = 0.885, P < 0.01). Similar adipogenic and fibrogenic FAPs were identified in humans and monkeys. In aged humans with metabolic syndrome and progressed Duchenne muscular dystrophy (DMD) patients, increased CFD expression was observed (P < 0.05 and P < 0.0001, respectively), which was positively correlated with adipogenic marker expression, including ADIPOQ (R2  = 0.303, P < 0.01; and R2  = 0.348, P < 0.01, respectively). The specificity of Postn/POSTN as a fibrogenic FAP marker was validated using a lineage-tracing mouse line. POSTN expression was elevated in Brahman FAPs (P < 0.0001) and DMD patients (P < 0.01) but not in aged humans. Strong interactions between vascular cells and FAPs were also identified.

CONCLUSIONS

Our study demonstrates the feasibility of beef cattle as a model for studying IMF and IMC. We illustrate the FAP programming during intramuscular adipogenesis and fibrogenesis and reveal the reliability of CFD as a predictor and biomarker of IMF accumulation in cattle and humans.

Tyrosine Kinase Inhibitor Profiling Using Multiple Forskolin-Responsive Reporter Cells

We have developed a highly sensitive promoter trap vector system using transposons to generate reporter cells with high efficiency. Using an EGFP/luciferase reporter cell clone responsive to forskolin, which is thought to activate adenylate cyclase, isolated from human chronic myelogenous leukemia cell line K562, we found several compounds unexpectedly caused reporter responses. These included tyrosine kinase inhibitors such as dasatinib and cerdulatinib, which were seemingly unrelated to the forskolin-reactive pathway. To investigate whether any other clones of forskolin-responsive cells would show the same response, nine additional forskolin-responsive clones, each with a unique integration site, were generated and quantitatively evaluated by luciferase assay. The results showed that each clone represented different response patterns to the reactive compounds. Also, it became clear that each of the reactive compounds could be profiled as a unique pattern by the 10 reporter clones. When other TKIs, mainly bcr-abl inhibitors, were evaluated using a more focused set of five reporter clones, they also showed unique profiling. Among them, dasatinib and bosutinib, and imatinib and bafetinib showed homologous profiling. The tyrosine kinase inhibitors mentioned above are approved as anticancer agents, and the system could be used for similarity evaluation, efficacy prediction, etc., in the development of new anticancer agents.

C-X-C Motif Chemokine 3 Promotes the Inflammatory Response of Microglia after Escherichia coli-Induced Meningitis

Meningitis is a major clinical manifestation of Escherichia coli (E. coli) infection characterized by inflammation of the meninges and subarachnoid space. Many chemokines are secreted during meningitic E. coli infection, of which C-X-C motif chemokine 3 (CXCL3) is the most highly expressed. However, it is unclear how CXCL3 plays a role in meningitic E. coli infection. Therefore, this study used in vitro and in vivo assays to clarify these contributions and to identify novel therapeutic targets for central nervous system inflammation. We found a significantly upregulated expression of CXCL3 in human brain microvascular endothelial cells and U251 cells after meningitic E. coli infection, and the CXCL3 receptor, C-X-C motif chemokine receptor 2 (CXCR2), was expressed in microglia. Furthermore, CXCL3 induced M1 microglia by selectively activating mitogen-activated protein kinases signaling and significantly upregulating tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, nitric oxide synthase 2 (NOS2), and cluster of differentiation 86 (CD86) expression levels, promoting an inflammatory response. Our findings clarify the role of CXCL3 in meningitic E. coli-induced neuroinflammation and demonstrate that CXCL3 may be a potential therapeutic target for future investigation and prevention of E. coli-induced neuroinflammation.

Pituitary Adenylate Cyclase-activating Polypeptide (PACAP) -derived Peptide MPAPO Stimulates Adipogenic Differentiation by Regulating the Early Stage of Adipogenesis and ERK Signaling Pathway

Regenerative medicine and tissue engineering have delivered new healing possibilities to the treatment of soft tissue defects, but the selection of seed cells is critical for treatment. Adipose-derived stem cells have perpetually been a preferred candidate for seed cells due to their wealthy sources, simple access, high plasticity, and powerful value-added capabilities. How to improve the efficiency of adipogenic differentiation is the key to the treatment. Pituitary adenylate cyclase-activating peptide, as a biologically active peptide secreted by the pituitary, is widely involved in regulating the body's sugar metabolism and lipid metabolism. However, the effects of MPAPO in ADSCs adipogenic differentiation remain unknown. Our results reveal that MPAPO treatment improves the adipogenic differentiation efficiency of ADSCs, including promoting the accumulation of lipid droplets and triglycerides, and the expression of adipocyte protein biomarkers PPARγ and C/EBPa. Additionally, the mechanism studies showed that the effective window of MPAPO-induced adipogenesis was the first 3 days during ADSCs differentiation. MPAPO selectively binds to the PAC1 receptor and promotes adipogenic differentiation of ADSCs by activating the ERK signaling pathway and elevating cell proliferation during postconfluent mitosis stage. Altogether, we demonstrate that MPAPO plays a crucial role in ADSCs adipogenesis, providing experimental basis and data for exploring therapeutic options in tissue defect repair.

Chronic restraint stress promotes the tumorigenic potential of oral squamous cell carcinoma cells by reprogramming fatty acid metabolism via CXCL3 mediated Wnt/β-catenin pathway

Chronic stress promotes tumor progression and may harm homeostasis of energy metabolism by disrupting key metabolic processes. Recently, emerging evidence that chemokines CXCL3 as a novel adipokine plays a new role in lipid metabolism and various human malignancies. However, the role and mechanism of the CXCL3 in oral squamous cell carcinoma (OSCC) progression and reprogramming lipid metabolism induced by chronic restraint stress is unclear. The analysis of transcriptome sequencing, LC-MS, GC-MS, CCK8, cell apoptosis assays, cell cycle analysis, qRT-PCR, ELISA, western blotting, immunofluorescence, immunohistochemistry, RNA interference and lentivirus transfection and a xenograft tumor growth and chronic restraint stress model were used to investigate the role of CXCL3 in the regulation of lipid metabolism and OSCC and explore the underlying molecular mechanisms. We showed that CXCL3 plays a critical role in in fatty acid de novo synthesis and tumor growth induced by chronic restraint stress. We demonstrated that chronic restraint stress promoted lipid accumulation, OSCC growth and metastasis in a mouse xenograft model. CXCL3 knockdown and FH535, an inhibitor of Wnt/β-catenin pathway, could attenuate fatty acid de novo synthesis, cell proliferation and epithelial-mesenchymal transition induced by chronic restraint stress in OSCC cells. Our findings demonstrate that chronic restraint stress promotes the proliferation and metastasis of OSCC by reprogramming fatty acid metabolism via CXCL3 mediated Wnt/β-catenin pathway. Our study provides novel insights to help understand the underlying mechanisms of CXCL3 in OSCC progression induced by chronic restraint stress.

Apolipoprotein A-IV reduced metabolic inflammation in white adipose tissue by inhibiting IKK and JNK signaling in adipocytes

Apolipoprotein A-IV (ApoA-IV) plays a role in satiation and serum lipid transport. In diet-induced obesity (DIO) C57BL/6J mice, ApoA-IV deficiency induced in ApoA-IV-/-knock-out (KO mice) resulted in increased bodyweight, insulin resistance (IR) and plasma free fatty acid (FFA), which was partially reversed by stable ApoA-IV-green fluorescent protein (KO-A4-GFP) transfection in KO mice. DIO KO mice exhibited increased M1 macrophages in epididymal white adipose tissue (eWAT) as well as in the blood. Based on RNA-sequencing analyses, cytokine-cytokine receptor interactions, T cell and B cell receptors, and especially IL-17 and TNF-α, were up-regulated in eWAT of DIO ApoA-IV KO compared with WT mice. Supplemented ApoA-IV suppressed lipopolysaccharide (LPS)-induced IKK and JNK phosphorylation in Raw264.7 macrophage cell culture assays. When the culture medium was supplemented to 3T3-L1 adipocytes they exhibited an increased sensitivity to insulin. ApoA-IV protects against obesity-associated metabolic inflammation mainly through suppression in M1 macrophages of eWAT, IL17-IKK and IL17-JNK activity.

The long noncoding RNA TARID regulates the CXCL3/ERK/MAPK pathway in trophoblasts and is associated with preeclampsia

BACKGROUND

The widely accepted explanation of preeclampsia (PE) pathogenesis is insufficient trophoblast invasion and impaired uterine spiral artery remodeling. However, the underlying molecular mechanism remains unclear.

METHODS

We performed transcriptome sequencing on placentas of normal and PE patients and identified 976 differentially expressed long noncoding RNAs (lncRNAs). TCF21 antisense RNA inducing demethylation (TARID) was one of the most significantly differentially expressed lncRNAs and was negatively correlated with the systolic and diastolic blood pressure in PE patients. Furthermore, we verified the effect of TARID on the biological behavior of trophoblasts and performed UID mRNA-seq to identify the effectors downstream of TARID. Then, co-transfection experiments were used to better illustrate the interaction between TARID and its downstream effector.

RESULTS

We concluded that the downregulation of TARID expression may inhibit trophoblast infiltration and spiral artery remodeling through inhibition of cell migration, invasion, and tube formation mediated through the CXCL3/ERK/MAPK pathway.

CONCLUSIONS

Overall, these findings suggested that TARID may be a therapeutic target for PE through the CXCL3/ERK/MAPK pathway.

Monitoring energy balance through clinical and serum biomarkers in patients with hematologic malignancies undergoing chemotherapy

Despite widespread concern about energy imbalance due to tumor and chemotherapy-related side effects, little is known about detailed variations in energy input, metabolic rate, and physical activity. This study explored changes in energy balance components and serum biomarkers of patients with hematologic malignancies undergoing chemotherapy. Our prospective study included 40 patients with hematologic malignancies hospitalized for chemotherapy. We measured energy balance components, physical function, and serum biomarkers at baseline and weekly after chemotherapy for 3 weeks. Significant weight loss, representing negative energy balance, occurred at 2 (p = 0.002) and 3 weeks (p < 0.001) post-chemotherapy. Statistically reduced oral intake was observed at 3 weeks post-chemotherapy (p = 0.040), and resting energy expenditure statistically decreased according to Harris-Benedict equation, but not to Penn State University equation. Physical function according to DEMMI score decreased significantly at 3 weeks post-chemotherapy (p = 0.002). Serum biomarker analysis demonstrated significant changes in albumin, total protein, CXCL13, and GDF15, with exception of leptin. Although conventional serum biomarkers (total protein and albumin) did not reach pathological states despite their statistical differences, subgroup analysis showed CXCL13 in weight loss group and GDF15 in reduced oral intake group were significantly changed. Over half of patients (65.0%, n = 26) suffered from energy imbalance associated with weight loss and reduced oral intake during chemotherapy. Serial laboratory results suggested that novel biomarkers (CXCL13, GDF15) could be correlated with cachexic state and reduced food intake. Monitoring clinical and serum biomarkers associated with energy balance together can help identify needs for nutritional support in patients with hematologic malignancies undergoing chemotherapy.

CXCL5 inhibits excessive oxidative stress by regulating white adipocyte differentiation

Chemokines have been well-documented as a major factor in immune cell migration and the regulation of immune responses. However, recent studies have reported that chemokines have diverse roles, both in immune cells and other cell types, including adipocytes. This study investigated the molecular functions of C-X-C motif chemokine ligand 5 (CXCL5) in white adipose cells using Cxcl5 knock-out (KO) mice fed a high-fat diet (HFD). The expression of Cxcl5 decreased by 90% during adipocyte differentiation and remained at a low level in mature adipocytes. Moreover, adipogenesis was enhanced when adipocytes were differentiated from the stromal vascular fraction (SFV) of Cxcl5 KO mice. Feeding an HFD increased the generation of reactive oxygen species (ROS) and promoted abnormal adipogenesis in Cxcl5 KO mice. Oxidative stress and insulin resistance occurred in Cxcl5 KO mice due to decreased antioxidant enzymes and failure to remove ROS. These results indicate the principal roles of CXCL5 in adipogenesis and ROS regulation in adipose tissue, further suggesting that CXCL5 is a valuable chemokine for metabolic disease research.

Secondary Metabolites in the Dendrobium heterocarpum Methanolic Extract and Their Impacts on Viability and Lipid Storage of 3T3-L1 Pre-Adipocytes

Although many natural products have proven their potential to regulate obesity through the modulation of adipocyte biology, none of them has yet been approved for clinical use in obesity therapy. This work aims to isolate valuable secondary metabolites from an orchid species (Dendrobium heterocarpum) and evaluate their possible roles in the growth and differentiation of 3T3-L1 pre-adipocytes. Six compounds were isolated from the orchid’s methanolic extracts and identified as amoenylin (1), methyl 3-(4-hydroxyphenyl) propionate (2), 3,4-dihydroxy-5,4’-dimethoxybibenzyl (3), dendrocandin B (4), dendrofalconerol A (5), and syringaresinol (6). Among these phytochemicals, compounds 2, 3, and 6 exhibited lower effects on the viability of 3T3-L1 cells, offering non-cytotoxic concentrations of ≲ 10 µM. Compared to others tested, compound 3 was responsible for the maximum reduction of lipid storage in 3T3-L1 adipocytes (IC₅₀ = 6.30 ± 0.10 µM). A set of protein expression studies unveiled that compound 3 at non-cytotoxic doses could suppress the expression of some key transcription factors in adipocyte differentiation (i.e., PPARγ and C/EBPα). Furthermore, this compound could deactivate some proteins involved in the MAPK pathways (i.e., JNK, ERK, and p38). Our findings prove that D. heterocarpum is a promising source to explore bioactive molecules capable of modulating adipocytic growth and development, which can potentially be assessed and innovated further as pharmaceutical products to defeat obesity.

Bone Marrow Adiposity in Models of Radiation- and Aging-Related Bone Loss Is Dependent on Cellular Senescence

Oxidative stress-induced reactive oxygen species, DNA damage, apoptosis, and cellular senescence have been associated with reduced osteoprogenitors in a reciprocal fashion to bone marrow adipocyte tissue (BMAT); however, a direct (causal) link between cellular senescence and BMAT is still elusive. Accumulation of senescent cells occur in naturally aged and in focally radiated bone tissue, but despite amelioration of age- and radiation-associated bone loss after senescent cell clearance, molecular events that precede BMAT accrual are largely unknown. Here we show by RNA-Sequencing data that BMAT-related genes were the most upregulated gene subset in radiated bones of C57BL/6 mice. Using focal radiation as a model to understand age-associated changes in bone, we performed a longitudinal assessment of cellular senescence and BMAT. Using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), RNA in situ hybridization of p21 transcripts and histological assessment of telomere dysfunction as a marker of senescence, we observed an increase in senescent cell burden of bone cells from day 1 postradiation, without the presence of BMAT. BMAT was significantly elevated in radiated bones at day 7, confirming the qRT-PCR data in which most BMAT-related genes were elevated by day 7, and the trend continued until day 42 postradiation. Similarly, elevation in BMAT-related genes was observed in bones of aged mice. The senolytic cocktail of Dasatinib (D) plus Quercetin (Q) (ie, D + Q), which clears senescent cells, reduced BMAT in aged and radiated bones. MicroRNAs (miRNAs or miRs) linked with senescence marker p21 were downregulated in radiated and aged bones, whereas miR-27a, a miR that is associated with increased BMAT, was elevated both in radiated and aged bones. D + Q downregulated miR-27a in radiated bones at 42 days postradiation. Overall, our study provides evidence that BMAT occurrence in oxidatively stressed bone environments, such as radiation and aging, is induced following a common pathway and is dependent on the presence of senescent cells. © 2022 American Society for Bone and Mineral Research (ASBMR).

Clinical significance and biological functions of chemokine CXCL3 in head and neck squamous cell carcinoma

CXCL3 plays extensive roles in tumorigenesis in various types of human cancers through its roles in tumor cell differentiation, invasion, and migration. However, the mechanisms of CXCL3 in head and neck squamous cell carcinoma (HNSCC) remain unclear. In our study, multiple databases were used to explore the expression level, prognostic value, and related mechanisms of CXCL3 in human HNSCC through bioinformatic methods. We also performed further experiments in vivo and in vitro to evaluate the expression of CXCL3 in a human head and neck tissue microarray and the underlying effect mechanisms of CXCL3 on the tumor biology of HNSCC tumor cells. The result showed that the expression level of CXCL3 in patients with HNSCC was significantly higher as compared with that in normal tissues (P<0.05). Kaplan–Meier survival analysis demonstrated that patients with high CXCL3 expression had a lower overall survival rate (P=0.038). CXCL3 was further identified as an independent prognostic factor for HNSCC patients by Cox regression analysis, and GSEA exhibited that several signaling pathways including Apoptosis, Toll-like receptor, Nod-like receptor, Jak-STAT, and MAPK signaling pathways may be involved in the tumorigenesis of HNSCC. CAL27 cells overexpressing or HNSCC cells treated with exogenous CXCL3 exhibited enhanced cell malignant behaviors, whereas down-regulating CXCL3 expression resulted in decreased malignant behaviors in HSC4 cells. In addition, CXCL3 may affect the expression of several genes, including ERK1/2, Bcl-2, Bax, STAT3, and NF-κB. In summary, our bioinformatics and experiment findings effectively suggest the information of CXCL3 expression, roles, and the potential regulatory network in HNSCC.

Dysregulation of Components of the Inflammasome Machinery After Bariatric Surgery: Novel Targets for a Chronic Disease

BACKGROUND

Obesity is a metabolic chronic disease with important associated morbidities and mortality. Bariatric surgery is the most effective treatment for maintaining long-term weight loss in severe obesity and, consequently, for decreasing obesity-related complications, including chronic inflammation.

AIM

To explore changes in components of the inflammasome machinery after bariatric surgery and their relation with clinical/biochemical parameters at baseline and 6 months after bariatric surgery.

PATIENTS AND METHODS

Twenty-two patients with morbid-obesity that underwent bariatric surgery (sleeve gastrectomy and Roux-en-Y gastric bypass) were included. Epidemiological/clinical/anthropometric/biochemical evaluation was performed at baseline and 6 months after bariatric surgery. Inflammasome components and inflammatory-associated factors [nucleotide-binding oligomerization domain-like receptors (NLRs), inflammasome activation components, cytokines and inflammation/apoptosis-related components, and cell-cycle and DNA-damage regulators) were evaluated in peripheral blood mononuclear cells (PBMCs) at baseline and 6 months after bariatric surgery. Clinical molecular correlations/associations were analyzed. Functional parameters (lipid accumulation/viability/apoptosis) were analyzed in response to specific inflammasome components silencing in liver HepG2 cells).

RESULTS

A profound dysregulation of inflammasome components after bariatric surgery was found, especially in NLRs and cell-cycle and DNA damage regulators. Several components were associated with baseline metabolic comorbidities including type 2 diabetes (C-C motif chemokine ligand 2/C-X-C motif chemokine receptor 1/sirtuin 1), hypertension (absent in melanoma 2/ASC/purinergic receptor P2X 7), and dyslipidemia [C-X-C motif chemokine ligand 3 (CXCL3)/NLR family pyrin domain containing (NLRP) 7) and displayed changes in their molecular profile 6 months after bariatric surgery. The gene expression fingerprint of certain factors NLR family CARD domain containing 4 (NLRC4)/NLRP12/CXCL3)/C-C motif chemokine ligand 8/toll-like receptor 4) accurately differentiated pre- and postoperative PBMCs. Most changes were independent of the performed surgical technique. Silencing of NLRC4/NLRP12 resulted in altered lipid accumulation, apoptosis rate, and cell viability in HepG2 cells.

CONCLUSION

Bariatric surgery induces a profound alteration in the gene expression pattern of components of the inflammasome machinery in PBMCs. Expression and changes of certain inflammasome components are associated to baseline metabolic comorbidities, including type 2 diabetes, and may be related to the improvement and reversion of some obesity-related comorbidities after bariatric surgery.

Phytochemicals from the flowers of Prunus persica (L.) Batsch: Anti-adipogenic effect of mandelamide on 3T3-L1 preadipocytes

Flowers of Prunus persica (L.) Batsch (Rosaceae), known as peach blossoms, have been reported to exert anti-obesity effects by improving hepatic lipid metabolism in obese mice. However, little is known regarding the anti-adipogenic effects of the phenolic compounds isolated from P. persica flowers. This study investigated the inhibitory effects of compounds extracted from P. persica flowers (PPF) on adipogenesis in 3T3-L1 murine preadipocytes using adipogenic differentiation assays. Additionally, we compared the anti-adipogenic effects of the phenolic compounds isolated from PPF, such as prunasin amide (1), amygdalin amide (2), prunasin acid (3), mandelamide (4), methyl caffeate (5), ferulic acid (6), chlorogenic acid (7), benzyl α-l-xylpyranosyl-(1 → 6)-β-d-glucopyranoside (8), prunin (9), naringenin (10), nicotiflorin (11), astragalin (12), afzelin (13), and uridine (14), on adipogenesis in 3T3-L1 murine preadipocytes. PPF and compounds 4-7 and 10 significantly inhibited adipogenesis. Among them, mandelamide (4) exhibited the maximum inhibitory activity with an IC₅₀ of 36.04 ± 1.82 μM. Additionally, mandelamide downregulated the expression of key adipogenic markers, such as extracellular signal-regulated kinase, c-Jun-N-terminal kinase, P38, CCAAT/enhancer-binding protein α, CCAAT/enhancer-binding protein β, peroxisome proliferator activated receptor γ, and glucocorticoid receptor. These results indicate that mandelamide is an active ingredient of PPF possessing anti-obesity properties.

Aging-dependent regulatory cells emerge in subcutaneous fat to inhibit adipogenesis

Adipose tissue mass and adiposity change throughout the lifespan. During aging, while visceral adipose tissue (VAT) tends to increase, peripheral subcutaneous adipose tissue (SAT) decreases significantly. Unlike VAT, which is linked to metabolic diseases, including type 2 diabetes, SAT has beneficial effects. However, the molecular details behind the aging-associated loss of SAT remain unclear. Here, by comparing scRNA-seq of total stromal vascular cells of SAT from young and aging mice, we identify an aging-dependent regulatory cell (ARC) population that emerges only in SAT of aged mice and humans. ARCs express adipose progenitor markers but lack adipogenic capacity; they secrete high levels of pro-inflammatory chemokines, including Ccl6, to inhibit proliferation and differentiation of neighboring adipose precursors. We also found Pu.1 to be a driving factor for ARC development. We identify an ARC population and its capacity to inhibit differentiation of neighboring adipose precursors, correlating with aging-associated loss of SAT.

High-throughput analysis of lung immune cells in a combined murine model of agriculture dust-triggered airway inflammation with rheumatoid arthritis

Rheumatoid arthritis (RA)-associated lung disease is a leading cause of mortality in RA, yet the mechanisms linking lung disease and RA remain unknown. Using an established murine model of RA-associated lung disease combining collagen-induced arthritis (CIA) with organic dust extract (ODE)-induced airway inflammation, differences among lung immune cell populations were analyzed by single cell RNA-sequencing. Additionally, four lung myeloid-derived immune cell populations including macrophages, monocytes/macrophages, monocytes, and neutrophils were isolated by fluorescence cell sorting and gene expression was determined by NanoString analysis. Unsupervised clustering revealed 14 discrete clusters among Sham, CIA, ODE, and CIA+ODE treatment groups: 3 neutrophils (inflammatory, resident/transitional, autoreactive/suppressor), 5 macrophages (airspace, differentiating/recruited, recruited, resident/interstitial, and proliferative airspace), 2 T-cells (differentiating and effector), and a single cluster each of inflammatory monocytes, dendritic cells, B-cells and natural killer cells. Inflammatory monocytes, autoreactive/suppressor neutrophils, and recruited/differentiating macrophages were predominant with arthritis induction (CIA and CIA+ODE). By specific lung cell isolation, several interferon-related and autoimmune genes were disproportionately expressed among CIA and CIA+ODE (e.g. Oasl1, Oas2, Ifit3, Gbp2, Ifi44, and Zbp1), corresponding to RA and RA-associated lung disease. Monocytic myeloid-derived suppressor cells were reduced, while complement genes (e.g. C1s1 and Cfb) were uniquely increased in CIA+ODE mice across cell populations. Recruited and inflammatory macrophages/monocytes and neutrophils expressing interferon-, autoimmune-, and complement-related genes might contribute towards pro-fibrotic inflammatory lung responses following airborne biohazard exposures in setting of autoimmune arthritis and could be predictive and/or targeted to reduce disease burden.

MicroRNA expression patterns in the brown fat of hibernating 13-lined ground squirrels

The sequence diversity of microRNAs (miRNAs) allows these potent regulators of mRNA fate to bind multiple transcripts, giving them the power to inhibit diverse cellular processes. Therefore, miRNAs may regulate metabolic rate suppression (also termed torpor), an adaptation used by capable species to reduce energy expenditure, minimize tissue damage, and prolong life. Small RNA-sequencing of brown fat from control (37 °C) and torpid (5-8 °C) ground squirrels revealed a central role for miRNAs in torpor. Unsupervised clustering analysis of all 319 conserved miRNAs showed separation of control and torpor samples, which was supported by PCA analysis. Of the 76 miRNAs that were differentially expressed, 45 were upregulated during torpor. KEGG and GO analyses suggested these miRNAs inhibit genes within the ribosome, oxidative phosphorylation, and glycolysis/gluconeogenesis pathways. Some of the most downregulated miRNAs (miR-1-3p, miR-206 and miR-133a/b) had significant Pearson correlation coefficients, suggesting these myomiRs may be co-expressed in control animals. Only 3 of the 16 enriched KEGG pathways were less targeted by miRNAs during torpor, including cytokine-cytokine receptor interactions and the coagulation and complement cascades, suggesting epigenetic or post-translation modifications may inhibit these potentially damaging processes. Alternatively, their activation could promote damage sensing, wound repair, and improve tissue homeostasis. Overall, miRNA-seq analysis of brown fat revealed a strong role for miRNAs in the downregulation of central metabolic processes necessary for MRS, and highlighted miRNAs that could be inhibited by antagomiRs to promote brown fat activity in potential obesity treatments, or that could be used to replicate torpor in non-hibernating mammals.

Preconditioning Human Adipose-Derived Stromal Cells on Decellularized Adipose Tissue Scaffolds Within a Perfusion Bioreactor Modulates Cell Phenotype and Promotes a Pro-regenerative Host Response

Cell-based therapies involving the delivery of adipose-derived stromal cells (ASCs) on decellularized adipose tissue (DAT) scaffolds are a promising approach for soft tissue augmentation and reconstruction. Our lab has recently shown that culturing human ASCs on DAT scaffolds within a perfusion bioreactor prior to implantation can enhance their capacity to stimulate in vivo adipose tissue regeneration. Building from this previous work, the current study investigated the effects of bioreactor preconditioning on the ASC phenotype and secretory profile in vitro, as well as host cell recruitment following implantation in an athymic nude mouse model. Immunohistochemical analyses indicated that culturing within the bioreactor increased the percentage of ASCs co-expressing inducible nitric oxide synthase (iNOS) and arginase-1 (Arg-1), as well as tumor necrosis factor-alpha (TNF-α) and interleukin-10 (IL-10), within the peripheral regions of the DAT relative to statically cultured controls. In addition, bioreactor culture altered the expression levels of a range of immunomodulatory factors in the ASC-seeded DAT. In vivo testing revealed that culturing the ASCs on the DAT within the perfusion bioreactor prior to implantation enhanced the infiltration of host CD31⁺ endothelial cells and CD26⁺ cells into the DAT implants, but did not alter CD45⁺F4/80⁺CD68⁺ macrophage recruitment. However, a higher fraction of the CD45⁺ cell population expressed the pro-regenerative macrophage marker CD163 in the bioreactor group, which may have contributed to enhanced remodeling of the scaffolds into host-derived adipose tissue. Overall, the findings support that bioreactor preconditioning can augment the capacity of human ASCs to stimulate regeneration through paracrine-mediated mechanisms.

Global DNA methylation pattern involved in the modulation of differentiation potential of adipogenic and myogenic precursors in skeletal muscle of pigs

Background

Skeletal muscle is a complex and heterogeneous tissue accounting for approximately 40% of body weight. Excessive ectopic lipid accumulation in the muscle fascicle would undermine the integrity of skeletal muscle in humans but endow muscle with marbling-related characteristics in farm animals. Therefore, the balance of myogenesis and adipogenesis is of great significance for skeletal muscle homeostasis. Significant DNA methylation occurs during myogenesis and adipogenesis; however, DNA methylation pattern of myogenic and adipogenic precursors derived from skeletal muscle remains unknown yet.

Methods

In this study, reduced representation bisulfite sequencing was performed to analyze genome-wide DNA methylation of adipogenic and myogenic precursors derived from the skeletal muscle of neonatal pigs. Integrated analysis of DNA methylation and transcription profiles was further conducted. Based on the results of pathway enrichment analysis, myogenic precursors were transfected with CACNA2D2-overexpression plasmids to explore the function of CACNA2D2 in myogenic differentiation.

Results

As a result, 11,361 differentially methylated regions mainly located in intergenic region and introns were identified. Furthermore, 153 genes with different DNA methylation and gene expression level between adipogenic and myogenic precursors were characterized. Subsequently, pathway enrichment analysis revealed that DNA methylation programing was involved in the regulation of adipogenic and myogenic differentiation potential through mediating the crosstalk among pathways including focal adhesion, regulation of actin cytoskeleton, MAPK signaling pathway, and calcium signaling pathway. In particular, we characterized a new role of CACNA2D2 in inhibiting myogenic differentiation by suppressing JNK/MAPK signaling pathway.

Conclusions

This study depicted a comprehensive landmark of DNA methylome of skeletal muscle-derived myogenic and adipogenic precursors, highlighted the critical role of CACNA2D2 in regulating myogenic differentiation, and illustrated the possible regulatory ways of DNA methylation on cell fate commitment and skeletal muscle homeostasis.

Supplementary information

The online version contains supplementary material available at 10.1186/s13287-020-02053-3.

Differential regulation of the immune system in a brain-liver-fats organ network during short-term fasting

OBJECTIVE

Fasting regimens can promote health, mitigate chronic immunological disorders, and improve age-related pathophysiological parameters in animals and humans. Several ongoing clinical trials are using fasting as a potential therapy for various conditions. Fasting alters metabolism by acting as a reset for energy homeostasis, but the molecular mechanisms underlying the beneficial effects of short-term fasting (STF) are not well understood, particularly at the systems or multiorgan level.

METHODS

We performed RNA-sequencing in nine organs from mice fed ad libitum (0 h) or subjected to fasting five times (2-22 h). We applied a combination of multivariate analysis, differential expression analysis, gene ontology, and network analysis for an in-depth understanding of the multiorgan transcriptome. We used literature mining solutions, LitLab™ and Gene Retriever™, to identify the biological and biochemical terms significantly associated with our experimental gene set, which provided additional support and meaning to the experimentally derived gene and inferred protein data.

RESULTS

We cataloged the transcriptional dynamics within and between organs during STF and discovered differential temporal effects of STF among organs. Using gene ontology enrichment analysis, we identified an organ network sharing 37 common biological pathways perturbed by STF. This network incorporates the brain, liver, interscapular brown adipose tissue, and posterior-subcutaneous white adipose tissue; hence, we named it the brain-liver-fats organ network. Using Reactome pathways analysis, we identified the immune system, dominated by T cell regulation processes, as a central and prominent target of systemic modulations during STF in this organ network. The changes we identified in specific immune components point to the priming of adaptive immunity and parallel the fine-tuning of innate immune signaling.

CONCLUSIONS

Our study provides a comprehensive multiorgan transcriptomic profiling of mice subjected to multiple periods of STF and provides new insights into the molecular modulators involved in the systemic immunotranscriptomic changes that occur during short-term energy loss.

Integrative Bioinformatics Analysis Reveals Potential Target Genes and TNFα Signaling Inhibition by Brazilin in Metastatic Breast Cancer Cells

OBJECTIVE

Metastasis is the most significant cause of morbidity and mortality in breast cancer patients. Previously, a combination of brazilin and doxorubicin has been shown to inhibit metastasis in HER2-positive breast cancer cells. This present study used an integrative bioinformatics approach to identify new targets and the molecular mechanism of brazilin in inhibiting metastasis in breast cancer.

METHODS

Cytotoxicity and mRNA arrays data were retreived from the DTP website, whereas genes that regulate metastatic breast cancer cells were retreived from PubMed with keywords "breast cancer metastasis". Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and Drug association analysis were carried out by using WEB-based GEne SeT AnaLysis Toolkit (WebGestalt). Construction of protein-protein interaction (PPI) network analysis was performed by STRING-DB v11.0 and Cytoscape, respectively. The genetic alterations of the potential therapeutic target genes of brazilin (PB) were analyzed using cBioPortal.

RESULTS

Analysis of cytotoxicity with the public database of COMPARE showed that brazilin exerts almost the same cytotoxicity in the NCI-60 cells panel showing by similar GI50 value, in which the lowest GI50 value was observed in MDA-MB 231, a metastatic breast cancer cells. KEGG enrichment indicated several pathways regulated by brazilin such as TNF signaling pathway, cellular senescence, and pathways in cancer. We found ten drugs that are associated with PB, including protein kinase inhibitors, TNFα inhibitors, enzyme inhibitors, and anti-inflammatory agents.

CONCLUSION

In conclusion, this study identified eight PB, including MMP14, PTGS2, ADAM17, PTEN, CCL2, PIK3CB, MAP3K8, and CXCL3. In addition, brazilin possibly inhibits metastatic breast cancer through inhibition of TNFα signaling. The study results study need to be validated with in vitro and in vivo studies to strengthen scientific evidence of the use of brazilin in breast cancer metastasis inhibition.

Sex-Specific Transcriptome Differences in Human Adipose Mesenchymal Stem Cells

In humans, sexual dimorphism can manifest in many ways and it is widely studied in several knowledge fields. It is increasing the evidence that also cells differ according to sex, a correlation still little studied and poorly considered when cells are used in scientific research. Specifically, our interest is on the sex-related dimorphism on the human mesenchymal stem cells (hMSCs) transcriptome. A systematic meta-analysis of hMSC microarrays was performed by using the Transcriptome Mapper (TRAM) software. This bioinformatic tool was used to integrate and normalize datasets from multiple sources and allowed us to highlight chromosomal segments and genes differently expressed in hMSCs derived from adipose tissue (hADSCs) of male and female donors. Chromosomal segments and differentially expressed genes in male and female hADSCs resulted to be related to several processes as inflammation, adipogenic and neurogenic differentiation and cell communication. Obtained results lead us to hypothesize that the donor sex of hADSCs is a variable influencing a wide range of stem cell biologic processes. We believe that it should be considered in biologic research and stem cell therapy.

Identification and characterization of adipose surface epitopes

Adipose tissue is a central regulator of metabolism and an important pharmacological target to treat the metabolic consequences of obesity, such as insulin resistance and dyslipidemia. Among the various cellular compartments, the adipocyte cell surface is especially appealing as a drug target as it contains various proteins that when activated or inhibited promote adipocyte health, change its endocrine function and eventually maintain or restore whole-body insulin sensitivity. In addition, cell surface proteins are readily accessible by various drug classes. However, targeting individual cell surface proteins in adipocytes has been difficult due to important functions of these proteins outside adipose tissue, raising various safety concerns. Thus, one of the biggest challenges is the lack of adipose selective surface proteins and/or targeting reagents. Here, we discuss several receptor families with an important function in adipogenesis and mature adipocytes to highlight the complexity at the cell surface and illustrate the problems with identifying adipose selective proteins. We then discuss that, while no unique adipocyte surface protein might exist, how splicing, posttranslational modifications as well as protein/protein interactions can create enormous diversity at the cell surface that vastly expands the space of potentially unique epitopes and how these selective epitopes can be identified and targeted.

CXCL13 is a differentiation- and hypoxia-induced adipocytokine that exacerbates the inflammatory phenotype of adipocytes through PHLPP1 induction

Hypoxia in adipose tissue is regarded as a trigger that induces dysregulation of the secretory profile in adipocytes. Similarly, local dysregulation of adipocytokine secretion is an initial event in the deleterious effects of obesity on metabolism. We previously reported that CXCL13 is highly produced during adipogenesis, however little is known about the roles of CXCL13 in adipocytes. Here, we found that hypoxia, as modeled by 1% O2 or exposure to the hypoxia-mimetic reagent desferrioxamine (DFO) has strong inductive effects on the expression of CXCL13 and CXCR5, a CXCL13 receptor, in both undifferentiated and differentiated adipocytes and in organ-cultured white adipose tissue (WAT). CXCL13 was also highly expressed in WAT from high fat diet-fed mice. Hypoxic profile, typified by increased expression of interleukin-6 (IL-6) and plasminogen activator inhibitor-1 (PAI-1) and decreased expression of adiponectin, was significantly induced by CXCL13 treatment during adipogenic differentiation. Conversely, the treatment of adipocytes with a neutralizing-antibody against CXCL13 as well as CXCR5 knockdown by specific siRNA effectively inhibited DFO-induced inflammation. The phosphorylation of Akt2, a protective factor of adipose inflammation, was significantly inhibited by CXCL13 treatment during adipogenic differentiation. Mechanistically, CXCL13 induces the expression of PHLPP1, an Akt2 phosphatase, through focal adhesion kinase (FAK) signaling; and correspondingly we show that CXCL13 and DFO-induced IL-6 and PAI-1 expression was blocked by Phlpp1 knockdown. Furthermore, we revealed the functional binding sites of PPARγ2 and HIF1-α within the Cxcl13 promoter. Taken together, these results indicate that CXCL13 is an adipocytokine that facilitates hypoxia-induced inflammation in adipocytes through FAK-mediated induction of PHLPP1 in autocrine and/or paracrine manner.

The CoV-2 outbreak: how hematologists could help to fight Covid-19

COVID-19 is a medical emergency, with 20 % of patients presenting with severe clinical manifestations. From the pathogenetic point of view, COVID-19 mimics two other well-known diseases characterized by cytokine storm and hyper-activation of the immune response, with consequent organ damage: acute graft-versus-host disease (aGVHD) and macrophage activation syndrome (MAS). Hematologists are confident with these situations requiring a prompt therapeutic approach for switching off the uncontrolled cytokine release; here, we discuss pros and cons of drugs that are already employed in hematology in the light of their possible application in COVID-19. The most promising drugs might be: Ruxolitinib, a JAK1/2 inhibitor, with a rapid and powerful anti-cytokine effect, tyrosine kinase inhibitors (TKIs), with their good anti-inflammatory properties, and perhaps the anti-Cd26 antibody Begelomab. We also present immunological data from gene expression experiments where TKIs resulted effective anti-inflammatory and pro-immune drugs. A possible combined treatment algorithm for COVID-19 is here proposed.

Ex Vivo Human Adipose Tissue Derived Mesenchymal Stromal Cells (ASC) Are a Heterogeneous Population That Demonstrate Rapid Culture-Induced Changes

Human adipose-derived mesenchymal stromal cells (ASC) are showing clinical promise for the treatment of a range of inflammatory and degenerative conditions. These lipoaspirate-derived cells are part of the abundant and accessible source of heterogeneous stromal vascular fraction (SVF). They are typically isolated and expanded from the SVF via adherent cell culture for at least 2 weeks and as such represent a relatively undefined population of cells. We isolated ex vivo ASC directly from lipoaspirate using a cocktail of antibodies combined with immunomagnetic bead sorting. This method allowed for the rapid enrichment of a defined and untouched ex vivo ASC population (referred to as MACS-derived ASC) that were then compared to culture-derived ASC. This comparison found that MACS-derived ASC contain a greater proportion of cells with activity in in vitro differentiation assays. There were also significant differences in the secretion levels of some key paracrine molecules. Moreover, when the MACS-derived ASC were subjected to adherent tissue culture, rapid changes in gene expression were observed. This indicates that culturing cells may alter the clinical utility of these cells. Although MACS-derived ASC are more defined compared to culture-derived ASC, further investigations using a comprehensive multicolor flow cytometry panel revealed that this cell population is more heterogeneous than previously appreciated. Additional studies are therefore required to more precisely delineate phenotypically distinct ASC subsets with the most therapeutic potential. This research highlights the disparity between ex vivo MACS-derived and culture-derived ASC and the need for further characterization.

Low intensity pulsed ultrasound (LIPUS) maintains osteogenic potency by the increased expression and stability of Nanog through spleen tyrosine kinase (Syk) activation

Mesenchymal stem cells (MSCs) are a powerful tool for cell-based, clinical therapies like bone regeneration. Therapeutic use of cell transplantation requires many cells, however, the expansion process needed to produce large quantities of cells reduces the differentiation potential of MSCs. Here, we examined the protective effects of low intensity pulsed ultrasound (LIPUS) on the maintenance of osteogenic potency. Primary osteoblastic cells were serially passaged between 2 and 12 times with daily LIPUS treatment. We found that LIPUS stimulation maintains osteogenic differentiation capacity in serially passaged cells, as characterized by improved matrix mineralization and Osteocalcin mRNA expression. Decreased expression of Nanog, Sox2, and Msx2, and increased expression of Pparg2 from serial passaging was recovered in LIPUS-stimulated cells. We found that LIPUS stimulation not only increased but also sustained expression of Nanog in primary osteoblasts and ST2 cells, a mouse mesenchymal stromal cell line. Nanog overexpression in serially passaged cells mimicked the recuperative effects of LIPUS on osteogenic potency, highlighting the important role of Nanog in LIPUS stimulation. Additionally, we found that spleen tyrosine kinase (Syk) is an important signaling molecule to induce Nanog expression in LIPUS-stimulated cells. Syk activation was regulated by both Rho-associated kinase 1 (ROCK1) and extracellular ATP in a paracrine manner. Interestingly, the LIPUS-induced increase in Nanog mRNA expression was regulated by ATP-P2X4-Syk Y323 activation, while the improvement of Nanog protein stability was controlled by the ROCK1-Syk Y525/526 pathway. Taken together, these results indicate that LIPUS stimulation recovers and maintains the osteogenic potency of serially passaged cells through a Syk-Nanog axis.

Combination of enzastaurin and ATRA exerts dose-dependent dual effects on ATRA-resistant acute promyelocytic leukemia cells

All-trans retinoic acid (ATRA) resistance continues to be a critical problem in acute promyelocytic leukemia (APL)-relapsed patients. In this study, a clinically achievable concentration of enzastaurin synergized with ATRA to induce differentiation and apoptosis in ATRA-resistant APL cell lines, NB4-R1 and NB4-R2. Mechanistically, although enzastaurin is a protein kinase Cβ (PKCβ) inhibitor, PKCβ may not be required since the activity of PKCβ was not suppressed by enzastaurin-ATRA (enz-ATRA) co-treatment, and another PKCβ-selective inhibitor did not mimic the effects of enzastaurin. An MEK inhibitor but not a RAF-1 inhibitor suppressed enz-ATRA treatment-triggered differentiation, activation of MEK/ERK and up-regulation of CCAAT/enhancer binding protein β (C/EBPβ) and/or PU.1. Therefore, RAF-1-independent MEK/ERK signaling was required for enz-ATRA treatment-induced differentiation via modulation of the protein levels of C/EBPβ and/or PU.1. Enz-ATRA treatment collapsed mitochondrial transmembrane potential without the activation of caspase-3, -6 and -7. Moreover, caspase-3/7- and caspase-6-specific inhibitors had no inhibitory effect on enz-ATRA treatment-triggered apoptosis. Therefore, enz-ATRA treatment-induced apoptosis was mitochondria-dependent but caspase-independent. Enz-ATRA treatment degraded PML-RARα, which may be involved in enz-ATRA treatment-induced dual effects and may also be beneficial for APL eradication. These findings may provide a potential therapy for ATRA-resistant APL patients.

The combination of UCN-01 and ATRA triggers differentiation in ATRA resistant acute promyelocytic leukemia cell lines via RAF-1 independent activation of MEK/ERK

With the introduction of arsenic trioxide and all-trans retinoic acid, the prognosis of acute promyelocytic leukemia has greatly improved. However, all-trans retinoic acid resistance is still unresolved in acute promyelocytic leukemia relapsed patients. In this study, the clinical achievable concentration of 7-hydroxystaurosporine synergized with all-trans retinoic acid to induce terminal differentiation in all-trans retinoic acid resistant acute promyelocytic leukemia cell lines. Though 7-hydroxystaurosporine is a PKC inhibitor, PKC might not be involved in the combination-induced differentiation since other PKC selective inhibitors, Gö 6976 and rottlerin failed to cooperate with all-trans retinoic acid to trigger differentiation. The combination significantly enhanced the protein level of CCAAT/enhancer binding protein β and/or PU.1 as well as activated MEK/ERK. U0126 (MEK specific inhibitor) not only suppressed the combination-induced differentiation but also restored the protein level of CCAAT/enhancer binding protein β and/or PU.1. However, RAF-1 inhibitor had no inhibitory effect on MEK activation and the combination-induced differentiation. Therefore, the combination overcame differentiation block via RAF-1 independent MEK/ERK modulation of the protein level of CCAAT/enhancer binding protein β and/or PU.1. These findings may provide a preclinical rationale for the potential role of this combination in the treatment of all-trans retinoic acid resistant acute promyelocytic leukemia patients.

Obesity-Induced Peritoneal Dissemination of Ovarian Cancer and Dominant Recruitment of Macrophages in Ascites

One-fifth of cancer deaths are associated with obesity. Because the molecular mechanisms by which obesity affects the progression of ovarian cancer (OC) are poorly understood, we investigated if obesity could promote the progression of OC cells using the postmenopausal ob/ob mouse model and peritoneal dissemination of mouse ID8 OC cells. Compared to lean mice, obese mice had earlier OC occurrence, greater metastasis throughout the peritoneal cavity, a trend toward shorter survival, and higher circulating glucose and proinflammatory chemokine CXCL1 levels. Ascites in obese mice had higher levels of macrophages (Mφ) and chemokines including CCL2, CXCL12, CXCL13, G-CSF and M-CSF. Omental tumor tissues in obese mice had more adipocytes than lean mice. Our data suggest that obesity may accelerate the peritoneal dissemination of OC through higher production of pro-inflammatory chemokines and Mφ recruitment.

The chemokine receptor CXCR2 contributes to murine adipocyte development

Chemokines are members of a large family of chemotactic cytokines that signal through their receptors to mediate leukocyte recruitment during inflammation and homeostasis. The chemokine receptor CXCR2 has largely been associated with neutrophil recruitment. However, there is emerging evidence of roles for chemokines and their receptors in processes other than leukocyte migration. We have previously demonstrated that CXCR2 knockout (KO) mice have thinner skin compared to wild‐type mice. Herein we demonstrate that this is due to a thinner subcutaneous adipose layer, as a result of fewer and smaller individual adipocytes. We observe a similar phenotype in other fat depots and present data that suggests this may be due to reduced expression of adipogenesis related genes associated with adipocyte specific CXCR2 signaling. Interestingly, this phenotype is evident in female, but not male, CXCR2 KO mice. These findings expand our understanding of nonleukocyte related chemokine receptor functions and help to explain some previously observed adipose‐related phenotypes in CXCR2 KO mice.

Effects of macrophages and CXCR2 on adipogenic differentiation of bone marrow mesenchymal stem cells

Macrophages and many chemokines are closely associated with the adipogenic differentiation of bone marrow mesenchymal stem cells (MSCs), but their roles in adipogenesis and the underlying mechanisms are not fully understood. Here, we first investigated the influence of macrophages on the differentiation of MSCs in vitro. We found that RAW246.7 macrophages cocultured with MSCs strongly blocked the differentiation progress and inhibited the expression of C-X-C motif chemokine ligand 1 (CXCL1) during adipogenesis. Coculture with MSCs mainly induced macrophages toward M2 polarization. In addition, the expression of CXCL1 and its receptor, C-X-C chemokine receptor type 2, CXCR2 are high during adipogenic differentiation of MSCs and not in mature adipocytes. Although CXCL1 had no effect on adipogenesis, treatment with a specific CXCR2 inhibitor, SB225002, hampered the adipogenic differentiation of MSCs. Blocking CXCR2 decreased p38 and Elk1 phosphorylation but increased the extracellular signal-regulated kinase (ERK) phosphorylation at the initial stage of adipogenesis, which suppressed the phosphorylation of p38/ERK-Elk1 at the late stage. Inhibition of ERK had similar effects on adipogenesis and Elk1 phosphorylation. Our data suggest that MSCs interact with macrophages during adipogenic differentiation. CXCR2 regulates the adipogenic differentiation of MSCs by altering the activation of the p38/ERK-Elk1 signaling pathway.

Adipogenic potential of perivascular adipose tissue preadipocytes is improved by coculture with primary adipocytes

Perivascular adipose tissue (PVAT) has the capacity to secrete vasoactive mediators with the potential to regulate vascular function. Given its location adjacent to the vasculature, PVAT dysfunction may be part of the pathophysiology of cardiovascular diseases. To study the mechanisms of PVAT dysfunction, several adipogenic models have been proposed. However, these approaches do not adequately reflect PVAT adipocyte phenotypes variability that depends on their anatomical location. Despite PVAT importance in modulating vascular function, to date, there is not a depot-specific adipogenic model for PVAT adipocytes. We present a model that uses coculturing of PVAT stromal vascular fraction derived preadipocytes with primary adipocytes isolated from the same PVAT. Preadipocytes were isolated from thoracic aorta PVAT and mesenteric resistance artery PVAT (mPVAT). Upon confluency, cells were induced to differentiate for 7 and 14 days using a standard protocol (SP) or standard protocol cocultured with primary adipocytes isolated from the same adipose depots (SPA) for 96, 120, and 144 h. SPA reduced the time for differentiation of stromal vascular fraction derived preadipocytes and increased their capacity to store lipids compared with SP as indicated by lipid accumulation, lipolytic responses, gene marker profile expression, and adiponectin secretion. The coculture system improved adipogenesis efficiency by enhancing lipid accumulation and reducing the time of induction, therefore, is a more efficient method compared to SP alone.

Effects of CXCL3 on migration, invasion, proliferation and tube formation of trophoblast cells

CXCL3 was reportedly associated with the invasion and metastasis of various malignancies, the role of CXCL3, however, in preeclampsia has not been fully discussed. We previously found placental CXCL3 level in severe preeclampsia was significantly lower than that in healthy pregnancy and exogenous recombinant human CXCL3 protein was able to promote trophoblasts' migration and proliferation. The current study, therefore, is further to investigate effects of endogenous CXCL3 on migration, invasion, proliferation, tube formation and apoptosis of trophoblasts. Immunofluorescence staining demonstrated that CXCL3 localized in both trophoblasts of placenta and HTR-8/SVneo cells. Moreover, data showed that migration, invasion, proliferation and tube-formation capability of HTR-8/SVneo cells transfected with siRNA-CXCL3 were suppressed by down-regulation of CXCL3, while those behaviors of HTR-8/SVneo cells transfected with pEZ-CXCL3 were enhanced by upregulation of CXCL3. Nevertheless, the apoptosis of HTR-8/SVneo cells was not affected by neither siRNA nor overexpression plasmid. The result suggests that CXCL3 is involved in migration, invasion, proliferation and tubule formation of trophoblasts and may play a key role in the pathogenesis of preeclampsia.

Constitutive activation of p46JNK2 is indispensable for C/EBPδ induction in the initial stage of adipogenic differentiation

Adipogenic differentiation plays a vital role in energy homeostasis and endocrine system. Several transcription factors, including peroxisome proliferator-activated receptor gamma 2 and CCAAT-enhancer-binding protein (C/EBP) α, β, and δ, are important for the process, whereas the stage-specific intracellular signal transduction regulating the onset of adipogenesis remains enigmatic. Here, we explored the functional role of c-jun N-terminal kinases (JNKs) in adipogenic differentiation using in vitro differentiation models of 3T3-L1 cells and primary adipo-progenitor cells. JNK inactivation with either a pharmacological inhibitor or JNK2-specific siRNA suppressed adipogenic differentiation, characterized by decreased lipid droplet appearance and the down-regulation of Adiponectin, fatty acid protein 4 (Fabp4), Pparg2, and C/ebpa expressions. Conversely, increased adipogenesis was observed by the inducible overexpression of p46JNK2 (JNK2-1), whereas it was not observed by that of p54JNK2 (JNK2-2), indicating a distinct role of p46JNK2. The essential role of JNK appears restricted to the early stage of adipogenic differentiation, as JNK inhibition in the later stages did not influence adipogenesis. Indeed, JNK phosphorylation was significantly induced at the onset of adipogenic differentiation. As for the transcription factors involved in early adipogenesis, JNK inactivation significantly inhibited the induction of C/ebpd, but not C/ebpb, during the initial stage of adipogenic differentiation. JNK activation increased C/ebpd mRNA and protein expression through the induction and phosphorylation of activating transcription factor 2 (ATF2) that binds to a responsive element within the C/ebpd gene promoter region. Taken together, these data indicate that constitutive JNK activity is specifically required for the initial stage differentiation events of adipocytes.