Ju-Suk Nam

Mouse cristin/R-spondin family proteins are novel ligands for the Frizzled 8 and LRP6 receptors and activate beta-catenin-dependent gene expression.

Wnt signaling plays critical biological roles during normal embryonic development and homeostasis in adults. In the canonical pathway, binding of Wnt ligands to the Frizzled (Fzd) receptor and the low density lipoprotein-related receptor (LRP) 5 or LRP6 coreceptor initiates downstream signaling events leading to gene activation by β-catenin and the T-cell factor (TCF)-lymphoid enhancer factor (LEF) family transcription factor complex. In this study, we provide several lines of evidence that the mouse Cristin/R-spondin family proteins function as Fzd8 and LRP6 receptor ligands and induce the canonical Wnt/β-catenin signaling pathway, leading to TCF-dependent gene activation. First, conditioned medium containing Cristin/R-spondin proteins effectively induced reporter activity in a TCF-binding site-dependent manner. Second, stimulation of cells with Cristin/R-spondin was accompanied by stabilization of endogenous β-catenin proteins and induction of canonical Wnt target genes. Third, Cristin/R-spondin proteins physically interacted with the extracellular domains of the LRP6 and Fzd8 receptors in vivo and in vitro. Interestingly, unlike canonical Wnt ligands, Cristin/R-spondin failed to form a ternary complex with both LRP6 and Fzd8 receptors, suggesting that R-spondin may activate the canonical Wnt signaling pathway by different mechanisms. Furthermore, Cristin/R-spondin proteins possess an intriguing positive modulatory activity on Wnt ligands, possibly through a direct interaction. Our findings expand the repertoire of ligands that induce β-catenin/TCF-dependent gene activation and implicate the presence of active β-catenin-dependent gene activation in a Wnt-free biological context.

Biomolecule-Mediated Synthesis of Selenium Nanoparticles using Dried Vitis vinifera (Raisin) Extract

Biomolecule-mediated nanoparticle synthesis has recently the gained attention of researchers due to its ecofriendly and non-toxic nature. Metabolites from plant extracts represent a better alternative to chemical methods to fulfill the growing demand for non-hazardous nanoparticle synthesis routes. Selenium and its nanoparticles have an extensive range of applications. Thus, biofabrication of selenium nanoparticles can be potentially useful in various fields. This study reports a green approach to biosynthesize selenium nanoparticles (Se-np) using dried Vitis vinifera (raisin) extracts. The biosynthesized selenium nanoparticles were characterized using transmission electron microscope (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy and Fourier transform infrared spectroscopy (FTIR). Transmission electron microscopic images revealed the spherical shape of biosynthesized selenium nanoparticles and a size range of 3–18 nm. Dynamic light scattering also confirmed the average particle size of 8.12 ± 2.5 nm with 0.212 PDI. The crystalline nature of selenium nanoparticles was confirmed by the X-ray diffraction study. Moreover, as inferred from the FTIR spectrum, the presence of highly stable lignin biopolymer on the surface of selenium nanoballs suggests a possible role as capping agent.

Genetic Polymorphism in Extracellular Regulators of Wnt Signaling Pathway

The Wnt signaling pathway is mediated by a family of secreted glycoproteins through canonical and noncanonical mechanism. The signaling pathways are regulated by various modulators, which are classified into two classes on the basis of their interaction with either Wnt or its receptors. Secreted frizzled-related proteins (sFRPs) are the member of class that binds to Wnt protein and antagonizes Wnt signaling pathway. The other class consists of Dickkopf (DKK) proteins family that binds to Wnt receptor complex. The present review discusses the disease related association of various polymorphisms in Wnt signaling modulators. Furthermore, this review also highlights that some of the sFRPs and DKKs are unable to act as an antagonist for Wnt signaling pathway and thus their function needs to be explored more extensively.

Computational biophysical, biochemical, and evolutionary signature of human R-spondin family proteins, the member of canonical Wnt/β-catenin signaling pathway.

In human, Wnt/β-catenin signaling pathway plays a significant role in cell growth, cell development, and disease pathogenesis. Four human (Rspo)s are known to activate canonical Wnt/β-catenin signaling pathway. Presently, (Rspo)s serve as therapeutic target for several human diseases. Henceforth, basic understanding about the molecular properties of (Rspo)s is essential. We approached this issue by interpreting the biochemical and biophysical properties along with molecular evolution of (Rspo)s thorough computational algorithm methods. Our analysis shows that signal peptide length is roughly similar in (Rspo)s family along with similarity in aa distribution pattern. In Rspo3, four N-glycosylation sites were noted. All members are hydrophilic in nature and showed alike GRAVY values, approximately. Conversely, Rspo3 contains the maximum positively charged residues while Rspo4 includes the lowest. Four highly aligned blocks were recorded through Gblocks. Phylogenetic analysis shows Rspo4 is being rooted with Rspo2 and similarly Rspo3 and Rspo1 have the common point of origin. Through phylogenomics study, we developed a phylogenetic tree of sixty proteins (n = 60) with the orthologs and paralogs seed sequences. Protein-protein network was also illustrated. Results demonstrated in our study may help the future researchers to unfold significant physiological and therapeutic properties of (Rspo)s in various disease models.

Antimicrobial Potential of Silver Nanoparticles Synthesized Using Medicinal Herb Coptidis rhizome

Coptidis rhizome contains several alkaloids that are bioactive agents of therapeutic value. We propose an eco-friendly method to synthesize biocompatible silver nanoparticles (AgNPs) using the aqueous extract of Coptidis rhizome. Silver ions were reduced to AgNPs using the aqueous extract of Coptidis rhizome, indicating that Coptidis rhizome can be used for the biosynthesis of AgNPs. The time and the concentration required for conversion of silver ions into AgNPs was optimized using UV-absorbance spectroscopy and inductively coupled plasma spectroscopy (ICP). Biosynthesized AgNPs showed a distinct UV-Visible absorption peak at 420 nm. ICP analysis showed that the time required for the completion of biosynthesis was around 20 min. Microscopic images showed that nanoparticles synthesized were of spherical shape and the average diameter of biosynthesized AgNPs was less than 30 nm. XRD analysis also confirmed the size of AgNps and revealed their crystalline nature. The interaction of AgNPs with phytochemicals present in Coptidis rhizome extract was observed in FTIR analysis. The antimicrobial property of AgNPs was evaluated using turbidity measurements. Coptidis rhizome-mediated biosynthesized AgNPs showed significant anti-bacterial activities against Escherichia coli and Staphylococcus aureus that are commonly involved in various types of infections, indicating their potential as an effective anti-bacterial agent.

Effect of Wnt3a on Keratinocytes Utilizing in Vitro and Bioinformatics Analysis

Wingless-type (Wnt) signaling proteins participate in various cell developmental processes. A suppressive role of Wnt5a on keratinocyte growth has already been observed. However, the role of other Wnt proteins in proliferation and differentiation of keratinocytes remains unknown. Here, we investigated the effects of the Wnt ligand, Wnt3a, on proliferation and differentiation of keratinocytes. Keratinocytes from normal human skin were cultured and treated with recombinant Wnt3a alone or in combination with the inflammatory cytokine, tumor necrosis factor α (TNFα). Furthermore, using bioinformatics, we analyzed the biochemical parameters, molecular evolution, and protein–protein interaction network for the Wnt family. Application of recombinant Wnt3a showed an anti-proliferative effect on keratinocytes in a dose-dependent manner. After treatment with TNFα, Wnt3a still demonstrated an anti-proliferative effect on human keratinocytes. Exogenous treatment of Wnt3a was unable to alter mRNA expression of differentiation markers of keratinocytes, whereas an altered expression was observed in TNFα-stimulated keratinocytes. In silico phylogenetic, biochemical, and protein–protein interaction analysis showed several close relationships among the family members of the Wnt family. Moreover, a close phylogenetic and biochemical similarity was observed between Wnt3a and Wnt5a. Finally, we proposed a hypothetical mechanism to illustrate how the Wnt3a protein may inhibit the process of proliferation in keratinocytes, which would be useful for future researchers.

Inflammatory Periprosthetic Bone Loss

Total hip arthroplasty [THA] is one of the most successful and effective procedures developed for the treatment of pain and lack of mobility associated with end-stage arthritis such as osteoarthritis and rheumatoid arthritis. Approximately 1.5 million joint arthroplastic operations are performed annually worldwide. THA, although considered an excellent surgical procedure, can be complicated by periprosthetic osteolysis. Periprosthetic osteolysis (also called ‘Particle disease’) is initiated by wear debris derived from the implant. In most long-term studies on hip arthroplasty, osteolysis related loosening, bone loss or periprosthetic fractures are the most frequent causes for revision surgeries (Talmo et al., 2006). Osteolysis is a particle-induced biologic process at the metal–bone or cement–bone interface of prosthetic implants, manifesting radiographically as scalloped focal or linear endosteal radiolucencies due to bone loss and resulting in the loosening of implants. In the early days of hip arthroplasty, radiolucencies around implants were noticed and were thought to be related to curing of acrylic cement, infection or neoplastic process. These were first described by Charnley in association with Teflon cups, though later were also observed in patients with stable implants (Charnley, 1966). In 1977, Willert and Semlitsch demonstrated the presence of macrophages in response to wear debris and concluded that the particles accumulate macrophages in pericapsular lymph drainage, leading to a foreign body response and eventual loosening of the implant (Willert, 1977). Goldring et al. described the synovial-like character of the interfacial membrane found and demonstrated the presence of prostaglandin E2 [PGE2] and collagenase secretion from the associated cells (Goldring et al., 1983). The early observations of osteolysis in cemented implants led to a general belief that osteolysis was related to the acrylic cement and the term ‘Cement disease’ was introduced. However, after the demonstration of lytic lesions in cementless implants, osteolysis is now considered to be a ‘Particle disease’, suggesting that wear-generated particulate debris is the main cause of periprosthetic osteolysis (Harris, 1995). Biologic responses to implant debris, the basis of periprosthetic tissue destruction, are due to a wide variety of complex events. Aseptic failure occurs later as a secondary issue to the chronic granulomatous and inflammatory response, which is stimulated and maintained by