Effect of Wnt-1 inducible signaling pathway protein-2 (WISP-2/CCN5), a downstream protein of Wnt signaling, on adipocyte differentiation

A Highly Bioactive Organic-Inorganic Nanoparticle for Activating Wnt10b Mediated Osteogenesis by Specifically Anchor CCN3 Protein

The rapid and efficient bone regeneration is still in unsatisfactory outcomes, demonstrating alternative strategy and molecular mechanism is necessary. Nanoscale biomaterials have shown some promising results in enhancing bone regeneration, however, the detailed interaction mechanism between nanomaterial and cells/tissue formation is not clear. Herein, a molecular-based inorganic-organic nanomaterial poly(citrate-siloxane) (PCS) is reported which can rapidly enhance osteogenic differentiation and bone formation through a special interaction with the cellular surface communication network factor 3 (CCN3), further activating the Wnt10b/β-catenin signaling pathway. Further studies revealed that the CCN3 is a key bridge protein for transmitting the osteoinductive effects of nano PCS into the intracellular compartment and activating Wnt10b. Specifically, the molecular mechanism studies confirmed that the inorganic silicon hydroxyl and the organic ester group can bound to the Thrombospondin-1 (TSP-1) and von Willebrand factor type C repeat module (vWC) structural domains of CCN3 respectively. The special material-protein interaction induced a conformational change of CCN3 and activated the function of the TSP-1 structural domain, which is further associated with the binding and activation of Wnt10b signaling. This study reveals the first targets of nanobiomaterials to promote tissue regeneration through cellular interactions and provides new ideas for the development of materiobiology.

The TSP-1 domain of the matricellular protein CCN5 is essential for its nuclear localization and anti-fibrotic function

The matricellular protein CCN5 exerts anti-fibrotic activity in hearts partly by inducing reverse trans-differentiation of myofibroblasts (MyoFBs) to fibroblasts (FBs). CCN5 consists of three structural domains: an insulin-like growth factor binding protein (IGFBP), a von Willebrand factor type C (VWC), and a thrombospondin type 1 (TSP-1). In this study, we set out to elucidate the roles of these domains in the context of the reverse trans-differentiation of MyoFBs to FBs. First, human cardiac FBs were trans-differentiated to MyoFBs by treatment with TGF-β; this was then reversed by treatment with recombinant human CCN5 protein or various recombinant proteins comprising individual or paired CCN5 domains. Subcellular localization of these recombinant proteins was analyzed by immunocytochemistry, cellular fractionation, and western blotting. Anti-fibrotic activity was also evaluated by examining expression of MyoFB-specific markers, α-SMA and fibronectin. Our data show that CCN5 is taken up by FBs and MyoFBs mainly via clathrin-mediated endocytosis, which is essential for the function of CCN5 during the reverse trans-differentiation of MyoFBs. Furthermore, we showed that the TSP-1 domain is essential and sufficient for endocytosis and nuclear localization of CCN5. However, the TSP-1 domain alone is not sufficient for the anti-fibrotic function of CCN5; either the IGFBP or VWC domain is needed in addition to the TSP-1 domain.

Single-cell transcriptomic sequencing analyses of cell heterogeneity during osteogenesis of human adipose-derived mesenchymal stem cells

Mesenchymal stem cells (MSCs) are known for their multilineage differentiation potential with immune-modulatory properties. The molecular underpinnings of differentiation remain largely undefined. In this study, we investigated the cellular and molecular features of chemically induced osteogenesis from MSC isolated from human adipose tissue (human adipose MSCs, hAMSCs) using single-cell RNA-sequencing (scRNA-seq). We found that a near complete differentiation of osteogenic clusters from hAMSCs under a directional induction. Both groups of cells are heterogeneous, and some of the hAMSCs cells are intrinsically prepared for osteogenesis, while variant OS clusters seems in cooperation with a due division of the general function. We identified a set of genes related to cell stress response highly expressed during the differentiation. We also characterized a series of transitional transcriptional waves throughout the process from hAMSCs to osteoblast and specified the unique gene networks and epigenetic status as key markers of osteogenesis.

WISP2 promotes cell proliferation via targeting ERK and YAP in ovarian cancer cells

Background

Wnt-inducible signaling pathway protein 2 (WISP2) is a wnt1-induced signaling pathway protein 2. Although studies indicate that WISP2 may promote the development of various tumors, its role in ovarian cancer remains unclear. The objective of the current study was to analyze the effects of WISP2 on the proliferation and migration of ovarian cancer cells in vitro and in vivo.

Results

Immunohistochemistry and western blotting indicated that WISP2 was highly expressed in various ovarian cancer tissues and cell lines, but weakly expressed in normal ovary tissue. WISP2 deletion inhibited cell growth, clone formation, and migration of ovarian cancer cells while promoting cell apoptosis and affecting the cell cycle. This growth inhibitory effect caused by WISP2 loss is due to the inhibition of phosphorylated extracellular signal-related kinase (p-ERK)1/2, as well as CCAAT/enhancer-binding protein α (CEBPα) and CEPBβ. In addition, WISP2 deletion also activated the Yes-associated protein (YAP).

Conclusion

WISP2 deletion inhibits ovarian cancer cell proliferation by affecting ERK signaling pathways.

Recombinant protein CCN5/WISP2 promotes islet cell proliferation and survival in vitro

Pancreatic ß cell proliferation, survival and function are key elements that need to be considered in developing novel antidiabetic therapies. We recently identified CCN5/WISP2 to have potential growth promoting properties when overexpressed in ß cells; however, further investigations are needed to validate those properties. In this study, we demonstrated that exogenous treatment of insulinoma cells and primary islets with recombinant CCN5 (rh-CCN5) protein enhanced the proliferative capacity which was correlated with activation of cell-cycle regulators CDK4 and cyclin D1. Furthermore, pre-incubation of these cells with rh-CCN5 enhanced their survival rate after being exposed to harsh treatments such as streptozotocin and high concentrations of glucose and free fatty acids. CCN5 as well caused an upregulation in the expression of key genes associated with ß cell identity and function such as GLUT-2 and GCK. Finally, CCN5 activated FAK and downstream ERK kinases which are known to stimulate cell proliferation and survival. Hence, our results validate the growth promoting activities of rh-CCN5 in ß cells and open the door for further investigations in vivo.

The matricellular protein CCN5 inhibits fibrotic deformation of retinal pigment epithelium

Retinal pigment epithelium (RPE) plays an essential role in maintaining retinal function, and its defect is thought to be critically implicated in various ocular disorders. This study demonstrated that the matricellular protein CCN5 was down-regulated in ARPE-19 cells treated with the pro-fibrotic agent transforming growth factor (TGF)-β. A recombinant adenovirus expressing CCN5 (AdCCN5) was used to restore the level of CCN5 in these cells. AdCCN5 prevented TGF-β-induced fibrotic changes, including disruption of tight junctions, up-regulation of mesenchymal marker proteins, and down-regulation of epithelial marker proteins. In addition, AdCCN5 prevented TGF-β-induced functional defects, including increased migratory activity and reduced phagocytic activity. Notably, AdCCN5 reversed morphological and functional defects pre-established by TGF-β prior to viral infection. The CCN5 level was down-regulated in RPE of 18-month-old Ccl2-/- mice, which exhibited retinal defects. Restoration of the CCN5 level via intravitreal injection of a recombinant adeno-associated virus expressing CCN5 (AAV9-CCN5) normalized the altered expression of mesenchymal, epithelial, and functional marker proteins, as assessed by western blotting and immunohistochemistry. Taken together, these data suggest that down-regulation of CCN5 is associated with fibrotic deformation of RPE under pathological conditions and that restoration of the CCN5 level effectively promotes recovery of deformed RPE.

CCN5/WISP2 and metabolic diseases

Obesity and type 2 diabetes increase worldwide at an epidemic rate. It is expected that by the year 2030 around 500 million people will have diabetes; predominantly type 2 diabetes. The CCN family of proteins has become of interest in both metabolic and other common human diseases because of their effects on mesenchymal stem cell (MSCs) proliferation and differentiation as well as being important regulators of fibrosis. We here review current knowledge of the WNT1 inducible signaling pathway protein 2 (CCN5/WISP2). It has been shown to be an important regulator of both these processes through effects on both the canonical WNT and the TGFβ pathways. It is also under normal regulation by the adipogenic commitment factor BMP4, in contrast to conventional canonical WNT ligands, and allows MSCs to undergo normal adipose cell differentiation. CCN5/WISP2 is highly expressed in, and secreted by, MSCs and is an important regulator of MSCs growth. In a transgenic mouse model overexpressing CCN5/WISP2 in the adipose tissue, we have shown that it is secreted and circulating in the blood, the mice develop hypercellular white and brown adipose tissue, have increased lean body mass and enlarged hypercellular hearts. Obese transgenic mice had improved insulin sensitivity. Interestingly, the anti-fibrotic effect of CCN5/WISP2 is protective against heart failure by inhibition of the TGFβ pathway. Understanding how CCN5/WISP2 is regulated and signals is important and may be useful for developing new treatment strategies in obesity and metabolic diseases and it can also be a target in regenerative medicine.

Dietary overload lithium decreases the adipogenesis in abdominal adipose tissue of broiler chickens

To investigate the toxic effects of dietary overload lithium on the adipogenesis in adipose tissue of chicken and the role of hypothalamic neuropeptide Y (NPY) in this process, one-day-old male chicks were fed with the basal diet added with 0 (control) or 100mg lithium/kg diet from lithium chloride (overload lithium) for 35days. Abdominal adipose tissue and hypothalamus were collected at day 6, 14, and 35. As a percentage of body weight, abdominal fat decreased (p<0.001) at day 6, 14, and 35, and feed intake and body weight gain decreased during day 7-14, and day 15-35 in overload lithium treated broilers as compared to control. Adipocyte diameter and DNA content in abdominal adipose tissue were significantly lower in overload-lithium treatment than control at day 35, although no significant differences were observed at day 6 and 14. Dietary overload lithium decreased (p<0.01) transcriptional expression of preadipocyte proliferation makers ki-67 (KI67), microtubule-associated protein homolog (TPX2), and topoisomerase 2-alpha (TOP2A), and preadipocyte differentiation transcriptional factors peroxisome proliferator-activated receptor-γ (PPARγ), and CCAAT/enhancer binding protein (C/EBP) α mRNA abundance in abdominal adipose tissue. In hypothalamus, dietary overload lithium influenced (p<0.001) NPY, and NPY receptor (NPYR) 6 mRNA abundance at day 6 and 14, but not at day 35. In conclusion, dietary overload lithium decreased the adipogenesis in abdominal adipose tissue of chicken, which was accompanied by depressing transcriptional expression of adipogenesis-associated factors. Hypothalamic NPY had a potential role in the adipogenesis in abdominal adipose tissue of broilers with a short-term overload lithium treatment.

WISP2 regulates preadipocyte commitment and PPARγ activation by BMP4

Inability to recruit new adipose cells following weight gain leads to inappropriate enlargement of existing cells (hypertrophic obesity) associated with inflammation and a dysfunctional adipose tissue. We found increased expression of WNT1 inducible signaling pathway protein 2 (WISP2) and other markers of WNT activation in human abdominal s.c. adipose tissue characterized by hypertrophic obesity combined with increased visceral fat accumulation and insulin resistance. WISP2 activation in the s.c. adipose tissue, but not in visceral fat, identified the metabolic syndrome in equally obese individuals. WISP2 is a novel adipokine, highly expressed and secreted by adipose precursor cells. Knocking down WISP2 induced spontaneous differentiation of 3T3-L1 and human preadipocytes and allowed NIH 3T3 fibroblasts to become committed to the adipose lineage by bone morphogenetic protein 4 (BMP4). WISP2 forms a cytosolic complex with the peroxisome proliferator-activated receptor γ (PPARγ) transcriptional activator zinc finger protein 423 (Zfp423), and this complex is dissociated by BMP4 in a SMAD-dependent manner, thereby allowing Zfp423 to enter the nucleus, activate PPARγ, and commit the cells to the adipose lineage. The importance of intracellular Wisp2 protein for BMP4-induced adipogenic commitment and PPARγ activation was verified by expressing a mutant Wisp2 protein lacking the endoplasmic reticulum signal and secretion sequence. Secreted Wnt/Wisp2 also inhibits differentiation and PPARγ activation, albeit not through Zfp423 nuclear translocation. Thus adipogenic commitment and differentiation is regulated by the cross-talk between BMP4 and canonical WNT signaling and where WISP2 plays a key role. Furthermore, they link WISP2 with hypertrophic obesity and the metabolic syndrome.

The roles of transforming growth factor-β and Smad3 signaling in adipocyte differentiation and obesity

We aimed at elucidating the roles of transforming growth factor (TGF)-β and Smad3 signaling in adipocyte differentiation (adipogenesis) and in the pathogenesis of obesity. TGF-β/Smad3 signaling in white adipose tissue (WAT) was determined in genetically obese (ob/ob) mice. The effect of TGF-β on adipogenesis was evaluated in mouse embryonic fibroblasts (MEF) isolated both from WT controls and Smad3 KO mice by Oil red-O staining and gene expression analysis. Phenotypic analyses of high-fat diet (HFD)-induced obesity in Smad3 KO mice compared to WT controls were performed. TGF-β/Smad3 signaling was elevated in WAT from ob/ob mice compared to the controls. TGF-β significantly inhibited adipogenesis in MEF, but the inhibitory effects of TGF-β on adipogenesis were partially abolished in MEF from Smad3 KO mice. TGF-β inhibited adipogenesis independent from the Wnt and β-catenin pathway. Smad3 KO mice were protected against HFD-induced insulin resistance. The size of adipocytes from Smad3 KO mice on the HFD was significantly smaller compared to the controls. In conclusion, the TGF-β/Smad3 signaling pathway plays key roles not only in adipogenesis but also in development of insulin resistance.

CCN5: biology and pathophysiology

CCN5 is one of six proteins in the CCN family. This family of proteins has been shown to play important roles in many processes, including proliferation, migration, adhesion, extracellular matrix regulation, angiogenesis, tumorigenesis, fibrosis, and implantation. In this review, we focus on the biological and putative pathophysiological roles of CCN5. This intriguing protein is structurally unique among the CCN family members, and has a unique biological activity profile as well.

CCN5: biology and pathophysiology

CCN5 is one of six proteins in the CCN family. This family of proteins has been shown to play important roles in many processes, including proliferation, migration, adhesion, extracellular matrix regulation, angiogenesis, tumorigenesis, fibrosis, and implantation. In this review, we focus on the biological and putative pathophysiological roles of CCN5. This intriguing protein is structurally unique among the CCN family members, and has a unique biological activity profile as well.

The CCN proteins: important signaling mediators in stem cell differentiation and tumorigenesis

The CCN proteins contain six members, namely CCN1 to CCN6, which are small secreted cysteine-rich proteins. The CCN proteins are modular proteins, containing up to four functional domains. Many of the CCN members are induced by growth factors, cytokines, or cellular stress. The CCNs show a wide and highly variable expression pattern in adult and in embryonic tissues. The CCN proteins can integrate and modulate the signals of integrins, BMPs, VEGF, Wnts, and Notch. The involvement of integrins in mediating CCN signaling may provide diverse context-dependent responses in distinct cell types. CCN1 and CCN2 play an important role in development, angiogenesis and cell adhesion, whereas CCN3 is critical to skeletal and cardiac development. CCN4, CCN5 and CCN6 usually inhibit cell growth. Mutations of Ccn6 are associated with the progressive pseudorheumatoid dysplasia and spondyloepiphyseal dysplasia tarda. In stem cell differentiation, CCN1, CCN2, and CCN3 play a principal role in osteogenesis, chondrogenesis, and angiogenesis. Elevated expression of CCN1 is associated with more aggressive phenotypes of human cancer, while the roles of CCN2 and CCN3 in tumorigenesis are tumor type-dependent. CCN4, CCN5 and CCN6 function as tumor suppressors. Although CCN proteins may play important roles in fine-tuning other major signaling pathways, the precise function and mechanism of action of these proteins remain undefined. Understanding of the biological functions of the CCN proteins would not only provide insight into their roles in numerous cellular processes but also offer opportunities for developing therapeutics by targeting CCN functions.