Scaffolding Role Research Articles

The Role of Calcium Phosphates and Electrospun 3D Scaffolds in Bone Tissue Engineering Scaffolds

Bone is a naturally occurring nano-composite structure bestowed with an innate regenerative potential. When this regenerative potential is not able to cope up with the bone loss, external assistance in the form of scaffolds, cells and signals are needed. This forms the basis of bone tissue engineering (BTE). CaP ceramics like hydroxyapatite (HA), calcium deficient hydroxyapatite (CDHA) and β-tricalcium phosphate (β-TCP) are an excellent choice of material for hard tissue reconstruction. However, they are brittle in nature and solid ceramic constructs are not conducive for vascularisation, thus limiting their application as scaffolds for BTE. Thus composite scaffolds of appropriate polymer/ceramic combination would greatly benefit BTE. Electrospinning is an extremely versatile methodology that is predominantly used for the fabrication of nanofibrous structures that closely mimic the ECM. Nevertheless, electrospinning of 3D structures is still a challenge. Various innovations in the electrospinning process are being tried out in order to produce true 3 dimensional structures that can act as scaffolds for BTE. The current paper reviews such technologies and also suggests the way forward for research in this area.

Formative Assessment and Achievement of Mathematics Students in Community Schools of Nepal

Formative assessment is one of the leading elements of every classroom instruction for making learning contextual and students centred. The formative assessment creates such space where a teacher as adult supporter plays the role of scaffolding on the learning performance of their students. I studied the formative assessment and students' achievement status in mathematics through survey research design. I used the contingency questionnaire as research tool under quantitative research approach. The study was conducted within the target population; total number of community schools and their mathematics students (i.e. 547) who have participated in District Level Examination in 2014. I employed simple random sampling procedure to select the sample respondents (i.e. 232). The contingency questionnaire for students with 0.74 value of internal consistency was used as a research tool to collect the basic information for the study. Regarding the theoretical framework, I used Tomlinson's Differentiated Classroom Instruction and Assessment: Philosophy of Differentiation. The research depicts that regularity of teachers' responses (check) or feedback on the students' classwork, homework, project work and tests have a creditable role in improving their students’ learning performance. Furthermore, project work, a form of formative assessment, helps to improve students’ learning performance through creating an opportunity for learning by doing, which also contributes to contextualize the abstract concept of mathematics.

NIMA-related kinase 9-mediated phosphorylation of the microtubule-associated LC3B protein at Thr-50 suppresses selective autophagy of p62/sequestosome 1.

Human ATG8 family proteins (ATG8s) are active in all steps of the macroautophagy pathway, and their lipidation is essential for autophagosome formation. Lipidated ATG8s anchored to the outer surface of the phagophore serve as scaffolds for binding of other core autophagy proteins and various effector proteins involved in trafficking or fusion events, whereas those at the inner surface are needed for assembly of selective autophagy substrates. Their scaffolding role depends on specific interactions between the LC3-interacting region (LIR) docking site (LDS) in ATG8s and LIR motifs in various interaction partners. LC3B is phosphorylated at Thr-50 within the LDS by serine/threonine kinase (STK) 3 and STK4. Here, we identified LIR motifs in STK3 and atypical protein kinase Cζ (PKCζ) and never in mitosis A (NIMA)-related kinase 9 (NEK9). All three kinases phosphorylated LC3B Thr-50 in vitro A phospho-mimicking substitution of Thr-50 impaired binding of several LIR-containing proteins, such as ATG4B, FYVE, and coiled-coil domain-containing 1 (FYCO1), and autophagy cargo receptors p62/sequestosome 1 (SQSTM1) and neighbor of BRCA1 gene (NBR1). NEK9 knockdown or knockout enhanced degradation of the autophagy receptor and substrate p62. Of note, the suppression of p62 degradation was mediated by NEK9-mediated phosphorylation of LC3B Thr-50. Consistently, reconstitution of LC3B-KO cells with the phospho-mimicking T50E variant inhibited autophagic p62 degradation. PKCζ knockdown did not affect autophagic p62 degradation, whereas STK3/4 knockouts inhibited autophagic p62 degradation independently of LC3B Thr-50 phosphorylation. Our findings suggest that NEK9 suppresses LC3B-mediated autophagy of p62 by phosphorylating Thr-50 within the LDS of LC3B.

A combination of mesenchymal stem cells and scaffolds promotes motor functional recovery in spinal cord injury: a systematic review and meta-analysis.

There is controversy about the role of scaffolds as an adjunctive therapy to mesenchymal stem cell (MSC) transplantation in spinal cord injury (SCI). Thus, the authors aimed to design a meta-analysis on preclinical evidence to evaluate the effectiveness of combination therapy of scaffold + MSC transplantation in comparison with scaffolds alone and MSCs alone in improving motor dysfunction in SCI. Electronic databases including Medline, Embase, Scopus, and Web of Science were searched from inception until the end of August 2018. Two independent reviewers screened related experimental studies. Animal studies that evaluated the effectiveness of scaffolds and/or MSCs on motor function recovery following experimental SCI were included. The findings were reported as standardized mean difference (SMD) and 95% confidence interval (CI). A total of 34 articles were included in the meta-analysis. Analyses show that combination therapy in comparison with the scaffold group alone (SMD 2.00, 95% CI 1.53-2.46, p < 0.0001), the MSCs alone (SMD 1.58, 95% CI 0.84-2.31, p < 0.0001), and the nontreated group (SMD 3.52, 95% CI 2.84-4.20, p < 0.0001) significantly improved motor function recovery. Co-administration of MSCs + scaffolds only in the acute phase of injury (during the first 3 days after injury) leads to a significant recovery compared to scaffold alone (SMD 2.18, p < 0.0001). In addition, the cotransplantation of scaffolds with bone marrow-derived MSCs (SMD 1.99, p < 0.0001) and umbilical cord-derived MSCs (SMD 1.50, p = 0.001) also improved motor function following SCI. The findings showed that scaffolds + MSCs is more effective than scaffolds and MSCs alone in improving motor function following SCI in animal models, when used in the acute phase of injury.

Biophysical Control of Bile Duct Epithelial Morphogenesis in Natural and Synthetic Scaffolds.

The integration of bile duct epithelial cells (cholangiocytes) in artificial liver culture systems is important in order to generate more physiologically relevant liver models. Understanding the role of the cellular microenvironment on differentiation, physiology, and organogenesis of cholangiocytes into functional biliary tubes is essential for the development of new liver therapies, notably in the field of cholangiophaties. In this study, we investigated the role of natural or synthetic scaffolds on cholangiocytes cyst growth, lumen formation and polarization. We demonstrated that cholangiocyte cyst formation efficiency can be similar between natural and synthetic matrices provided that the mechanical properties of the hydrogels are matched. When using synthetic matrices, we also tried to understand the impact of elasticity, matrix metalloprotease-mediated degradation and integrin ligand density on cyst morphogenesis. We demonstrated that hydrogel stiffness regulates cyst formation. We found that controlling integrin ligand density was key in the establishment of large polarized cysts of cholangiocytes. The mechanism of lumen formation was found to rely on cell self-organization and proliferation. The formed cholangiocyte organoids showed a good MDR1 (multi drug resistance protein) transport activity. Our study highlights the advantages of fully synthetic scaffold as a tool to develop bile duct models.

The impact of the use of bioresorbable vascular scaffolds and drug-coated balloons in coronary bifurcation lesions

BackgroundDespite the improvement in techniques and tools, coronary lesions involving a bifurcation are still challenging and the outcome with drug-eluting stents is not always optimal. The role of bioresorbable vascular scaffolds (BVS) and drug-coated balloons (DCB) in this setting has not been adequately investigated yet.ResultsFrom the databases of 6 italian centers with high proficiencies in newer technologies, we retrospectively collected all consecutive cases of coronary bifurcations managed or attempted with the implantation of at least one BVS in the main vessel and the use of one DCB in the side branch (SB). Primary study endpoint was the occurrence of major adverse cardiovascular events (MACE) at the longest available follow-up. Fourty patients fulfilled the enrollment criterion, 22.5% had diabetes and 50% an acute coronary syndrome. Average syntax score was 15.04 ± 7.18, all lesions were de novo, and 27 patients (67.5%) had a type 1,1,1 Medina lesion. Twenty-three lesions (57.5%) involved the proximal left anterior-descending artery/first diagonal branch. Only 32.5% of patients underwent an intravascular imaging-guided angioplasty. Average lesion length was 21.4 mm in the main vessel and 11.49 mm in the SB. MV was always predilated and BVS received a postdilation in 100% of the cases. In 42.5% of the cases, the DCB was used during final kissing balloon inflation, and in no cases, a stent/BVS was required in the SB. Procedural success was achieved in 100% of the cases. After an average follow-up of 15.5 (± 11.5) months, we observed no MACE with only one case of target vessel revasularization (2.5%).ConclusionsManagement of coronary bifurcation lesions with the use of newer technologies including BVS and DCB seems feasible and effective at mid-term and long-term clinical follow-up.

LATS1 but not LATS2 represses autophagy by a kinase-independent scaffold function

Autophagy perturbation represents an emerging therapeutic strategy in cancer. Although LATS1 and LATS2 kinases, core components of the mammalian Hippo pathway, have been shown to exert tumor suppressive activities, here we report a pro-survival role of LATS1 but not LATS2 in hepatocellular carcinoma (HCC) cells. Specifically, LATS1 restricts lethal autophagy in HCC cells induced by sorafenib, the standard of care for advanced HCC patients. Notably, autophagy regulation by LATS1 is independent of its kinase activity. Instead, LATS1 stabilizes the autophagy core-machinery component Beclin-1 by promoting K27-linked ubiquitination at lysine residues K32 and K263 on Beclin-1. Consequently, ubiquitination of Beclin-1 negatively regulates autophagy by promoting inactive dimer formation of Beclin-1. Our study highlights a functional diversity between LATS1 and LATS2, and uncovers a scaffolding role of LATS1 in mediating a cross-talk between the Hippo signaling pathway and autophagy.

Deconstructing tissue engineered trachea: Assessing the role of synthetic scaffolds, segmental replacement and cell seeding on graft performance

The ideal construct for tracheal replacement remains elusive in the management of long segment airway defects. Tissue engineered tracheal grafts (TETG) have been limited by the development of graft stenosis or collapse, infection, or lack of an epithelial lining. We applied a mouse model of orthotopic airway surgery to assess the impact of three critical barriers encountered in clinical applications: the scaffold, the extent of intervention, and the impact of cell seeding and characterized their impact on graft performance. First, synthetic tracheal scaffolds electrospun from polyethylene terephthalate / polyurethane (PET/PU) were orthotopically implanted in anterior tracheal defects of C57BL/6 mice. Scaffolds demonstrated complete coverage with ciliated respiratory epithelium by 2 weeks. Epithelial migration was accompanied by macrophage infiltration which persisted at long term (>6 weeks) time points. We then assessed the impact of segmental tracheal implantation using syngeneic trachea as a surrogate for the ideal tracheal replacement. Graft recovery involved local upregulation of epithelial progenitor populations and there was no evidence of graft stenosis or necrosis. Implantation of electrospun synthetic tracheal scaffold for segmental replacement resulted in respiratory distress and required euthanasia at an early time point. There was limited epithelial coverage of the scaffold with and without seeded bone marrow-derived mononuclear cells (BM-MNCs). We conclude that synthetic scaffolds support re-epithelialization in orthotopic patch implantation, syngeneic graft integration occurs with focal repair mechanisms, however epithelialization in segmental synthetic scaffolds is limited and is not influenced by cell seeding. Statement of significanceThe life-threatening nature of long-segment tracheal defects has led to clinical use of tissue engineered tracheal grafts in the last decade for cases of compassionate use. However, the ideal tracheal reconstruction using tissue-engineered tracheal grafts (TETG) has not been clarified. We addressed the core challenges in tissue engineered tracheal replacement (re-epithelialization and graft patency) by defining the role of cell seeding with autologous bone marrow-derived mononuclear cells, the mechanism of respiratory epithelialization and proliferation, and the role of the inflammatory immune response in regeneration. This research will facilitate comprehensive understanding of cellular regeneration and neotissue formation on TETG, which will permit targeted therapies for accelerating re-epithelialization and attenuating stenosis in tissue engineered airway replacement.

A Heme Propionate Staples the Structure of Cytochrome c for Methionine Ligation to the Heme Iron.

Ligand-switch reactions at the heme iron are common in biological systems, but their mechanisms and the features of the polypeptide fold that support dual ligation are not well understood. In cytochrome c (cyt c), two low-stability loops (Ω-loop C and Ω-loop D) are connected by the heme propionate HP6. At alkaline pH, the native Met80 ligand from Ω-loop D switches to a Lys residue from the same loop. Deprotonation of an as yet unknown group triggers the alkaline transition. We have created the two cyt c variants T49V/K79G and T78V/K79G with altered connections of these two loops to HP6. Electronic absorption, NMR, and EPR studies demonstrate that at pH 7.4 ferric forms of these variants are Lys-ligated, whereas ferrous forms maintain the native Met80 ligation. Measurements of protein stability, cyclic voltammetry, pH-jump and gated electron-transfer kinetics have revealed that these Thr to Val substitutions greatly affect the alkaline transition in both ferric and ferrous proteins. The substitutions modify the stability of the Met-ligated species and reduction potentials of the heme iron. The kinetics of ligand-switch processes are also altered, and analyses of these effects implicate redox-dependent differences in metal-ligand interactions and the role of the protein dynamics, including cross-talk between the two Ω-loops. With the two destabilized variants, it is possible to map energy levels for the Met- and Lys-ligated species in both ferric and ferrous proteins and assess the role of the protein scaffold in redox-dependent preferences for these two ligands. The estimated shift in the heme iron reduction potential upon deprotonation of the "trigger" group is consistent with those associated with deprotonation of an HP, suggesting that HP6, on its own or as a part of a hydrogen-bonded cluster, is a likely "trigger" for the Met to Lys ligand switch.

Kindergartners’ Strategic Talk During Partner Reading

This descriptive, qualitative study seeks to contribute to the corpus of early literacy research by examining the role of comprehension strategies and teacher scaffolding on kindergartners’ talk during partner reading. Although comprehension is a robust line of inquiry, previous research has focused on comprehension strategy use by students in the intermediate grades and above. The purpose of this study is to describe kindergartners’ abilities to enact comprehension strategies and their use of those strategies with a partner and in small group discussions during various reading experiences. Findings suggest that kindergarten students can read strategically by encouraging both comprehension and decoding strategies while reading. Implications for teachers and future research are discussed at length, including the importance of strategically scaffolding young students during reading instruction and providing a variety of authentic opportunities for students to practice their use of comprehension strategies.

Experimental Study on Construction of Tissue Engineered Bone by Autologous Oxygen Release Nano-Bionic Scaffold Combined with Bone Morphogenetic Protein-2 Induced Bone Marrow Mesenchymal Stem Cells

Bone marrow mesenchymal stem cells (BMSCs) are used for bone tissue engineering. BMP-2 and autologous oxygen-releasing nano-bionic scaffolds promote bone differentiation of BMSCs. Our study intends to evaluate the role of autologous oxygen-releasing nano-bionic scaffolds combined with BMP-2-induced BMSCs in the construction of tissue engineered bone. Rat BMSCs were isolated and transfected with NC (negative control group) and BMP-2 (BMP-2 plasmid group), respectively. Healthy male SD rats were randomly and equally divided into fracture group, negative control group and the BMP-2 group which was implanted with autologous oxygen-releasing nano-bionic scaffolds to synthesize BMSCs and transfected with BMP-2 plasmids respectively followed by analysis of osteophytes growth, ALP activity, expression of BMP-2, type II collagen, Runx2 and OC by real time PCR, TGF-β1 secretion by ELISA and BMP-2 protein expression by western blot. BMSCs induced by autologous oxygen release nano-bionic scaffold combined with BMP-2 can significantly promote the increase of bone mineral density, increase the expression of Runx2 and OC, promote ALP activity, upregulate type II collagen, BMP-2 mRNA and protein, and TGF-β1 secretion compared to fracture group (P &lt; 0.05). The BMSCs induced by autologous oxygen-releasing nanobionic scaffolds transfected with BMP-2 had a more significant effect on bone repair. Autologous oxygen-releasing nano-bionic scaffolds combined with BMP-2-induced BMSCs can promote bone healing by regulating BMP-2 and increasing osteogenesis at the bone defect.

WHAMM initiates autolysosome tubulation by promoting actin polymerization on autolysosomes

WHAMM, a member of the Wiskott-Aldrich syndrome protein (WASP) family, is an actin nucleation promoting factor (NPF) that also associates with membranes and microtubules. Here we report that WHAMM is required for autophagic lysosome reformation (ALR). WHAMM knockout causes impairment of autolysosome tubulation, which results in accumulation of enlarged autolysosomes during prolonged starvation. Mechanistically, WHAMM is recruited to the autolysosome membrane through its specific interaction with PI(4,5)P2. WHAMM then works as an NPF which promotes assembly of an actin scaffold on the surface of the autolysosome to promote autolysosome tubulation. Our study demonstrates an unexpected role of the actin scaffold in regulating autophagic lysosome reformation.

TRPC6 Binds to and Activates Calpain, Independent of Its Channel Activity, and Regulates Podocyte Cytoskeleton, Cell Adhesion, and Motility.

Mutations in the transient receptor potential channel 6 (TRPC6) gene are associated with an inherited form of FSGS. Despite widespread expression, patients with TRPC6 mutations do not present with any other pathologic phenotype, suggesting that this protein has a unique yet unidentified role within the target cell for FSGS, the kidney podocyte. We generated a stable TRPC6 knockout podocyte cell line from TRPC6 knockout mice. These cells were engineered to express wild-type TRPC6, a dominant negative TRPC6 mutation, or either of two disease-causing mutations of TRPC6, G109S or K874*. We extensively characterized these cells using motility, detachment, and calpain activity assays; immunofluorescence; confocal or total internal reflection fluorescence microscopy; and western blotting. Compared with wild-type cells, TRPC6-/- podocytes are less motile and more adhesive, with an altered actin cytoskeleton. We found that TRPC6 binds to ERK1/2 and the actin regulatory proteins, caldesmon (a calmodulin- and actin-binding protein) and calpain 1 and 2 (calcium-dependent cysteine proteases that control the podocyte cytoskeleton, cell adhesion, and motility via cleavage of paxillin, focal adhesion kinase, and talin). Knockdown or expression of the truncated K874* mutation (but not expression of the gain-of-function G019S mutation or dominant negative mutant of TRPC6) results in the mislocalization of calpain 1 and 2 and significant downregulation of calpain activity; this leads to altered podocyte cytoskeleton, motility, and adhesion-characteristics of TRPC6-/- podocytes. Our data demonstrate that independent of TRPC6 channel activity, the physical interaction between TRPC6 and calpain in the podocyte is important for cell motility and detachment and demonstrates a scaffolding role of the TRPC6 protein in disease.

Facilitating Diagnostic Competences in Higher Education\u2014a Meta-Analysis in Medical and Teacher Education

Facilitating diagnostic competences is an important objective of higher education for many professions. This meta-analysis of 35 empirical studies builds on a conceptual framework and investigates the role of problem-solving, scaffolding, and context to foster diagnostic competences in learners with lower and higher professional knowledge bases. A moderator analysis investigates which type of scaffolding is effective for different levels of learners’ knowledge bases, as well as the role of the diagnostic context. Instructional support has a moderate positive effect (g = .39; CI [.22; .56]; p = .001). Diagnostic competences are facilitated effectively through problem-solving independent of the learners’ knowledge base. Scaffolding types providing high levels of guidance are more effective for less advanced learners, whereas scaffolding types relying on high levels of self-regulation are more effective for advanced learners.

More Than Child’s Play: The Scaffolding Role of Toys, Games, and Play in Children’s Literature

ABSTRACT Scholars have explored the way books about toys inculcate consumer, racist, and sexist ideologies in the young, subversively controllinng their attitudes and behavior. Judging from the scholarship in this area, teachers, librarians, and parents may hesitate before recommending or purchasing toy-centered stories for children. Using insights from play theorists and psychology researchers, this article argues that toy fiction can empower children by both acknowledging their marginalized status and providing models of coping, learning, and agency.

Epithelial-mesenchymal transition of cancer cells using bioengineered hybrid scaffold composed of hydrogel/3D-fibrous framework

Cancer cells undergoing epithelial-mesenchymal transition (EMT) acquire stem cell-like phenotype associated with malignant behaviour, chemoresistance, and relapse. Current two-dimensional (2D) in-vitro culture models of tumorigenesis are inadequate to replicate the complexity of in-vivo microenvironment. Therefore, the generation of functional three-dimensional (3D) constructs is a fundamental prerequisite to form multi-cellular tumour spheroids for studying basic pathological mechanisms. In this study, we focused on two major points (i) designing and fabrication of 3D hybrid scaffolds comprising electrospun fibers with cancer cells embedded within hydrogels, and (ii) determining the potential roles of 3D hybrid scaffolds associated with EMT in cancer progression and metastasis. Our findings revealed that 3D hybrid scaffold enhances cell proliferation and induces cancer cells to undergo EMT, as demonstrated by significant up-regulation of EMT associated transcriptional factors including Snail1, Zeb1, and Twist2; and mesenchymal markers whereas epithelial marker, E-Cadherin was downregulated. Remarkably, this induction is independent of cancer cell-type as similar results were obtained for breast cancer cells, MDA-MB-231 and gastric cancer cells, MKN74. Moreover, the hybrid scaffolds enrich aggressive cancer cells with stem cell properties. We showed that our 3D scaffolds could trigger EMT of cancer cells which could provide a useful model for studying anticancer therapeutics against metastasis.

Acetylcholinesterase inhibitors with a thiazolium scaffold: structural features and binding modes

Aim. To assess the structural features of substituents and the role of a thiazolium scaffold in mechanisms of acetylcholinesterase inhibition by thiazolium salts.Results and discussion. On the basis of activities of model compounds at pH 6.5 and pH 8.0 and the results of molecular docking the binding modes of quaternized derivatives of 5-(2-hydroxyethyl)-4-methylthiazole with different substituents in position 3 and 5 were analyzed. The presence of (N)3-benzyl substituent provides the inhibitor fixation in the catalytic anionic site, whereas acyl fragments of substituents in position 5 are situated in the peripheral anionic site. Logarithms of ІС50 values of the thiazolium inhibitors, except for the compounds containing O-acyl carbocyclic groups, linearly depend on the calculated docking energies in case of a thiazolium, ion as well as a neutral tetrahedral intermediate of the thiazolium ring opening.Experimental part. Thiazolium salts were synthesized by the known methods. The activity of acetylcholinesterase was studied by Ellman’s method. Molecular docking to the active site of acetylcholinesterase was performed using an AutoDock 4.2 program.Conclusions. Structural fragments of substituents in positions 3 and 5 of the heterocyclic scaffold provide binding of the inhibitor in the catalytic anionic site and the peripheral anionic site of acetylcholinesterase, respectively. The heterocyclic scaffold can be bound to the enzyme as a thiazolium ion or a neutral tetrahedralintermediate of the ring opening reaction.

Nonclassical Ligand-Independent Regulation of Go Protein by an Orphan Class C G-Protein-Coupled Receptor.

The orphan G-protein-coupled receptor (GPCR) GPR158 is expressed in the brain, where it is involved in the osteocalcin effect on cognitive processes, and at the periphery, where it may contribute to glaucoma and cancers. GPR158 forms a complex with RGS7-β5, leading to the regulation of neighboring GPCR-induced Go protein activity. GPR158 also interacts with αo, although no canonical Go coupling has been reported. GPR158 displays three VCPWE motifs in its C-terminal domain that are putatively involved in G-protein regulation. Here, we addressed the scaffolding function of GPR158 and its VCPWE motifs on Go. We observed that GPR158 interacted with and stabilized the amount of RGS7-β5 through a 50-residue region downstream of its transmembrane domain and upstream of the VCPWE motifs. We show that two VCPWE motifs are involved in αo binding. Using a Gαo-βγ bioluminescence resonance energy transfer (BRET) sensor, we found that GPR158 decreases the BRET signal as observed upon G-protein activation; however, no constitutive activity of GPR158 could be detected through the measurement of various G-protein-mediated downstream responses. We propose that the effect of GPR158 on Go is unlikely due to a canonical activation of Go, but rather to the trapping of Gαo by the VCPWE motifs, possibly leading to its dissociation from βγ Such action of GPR158 is expected to prolong the βγ activity, as also observed with some activators of G-protein signaling. Taken together, our data revealed a complex functional scaffolding or signaling role for GPR158 controlling Go through an original mechanism.

Plasmodium pseudo-Tyrosine Kinase-like binds PP1 and SERA5 and is exported to host erythrocytes

Pseudokinases play key roles in many biological processes but they are poorly understood compared to active kinases. Eight putative pseudokinases have been predicted in Plasmodium species. We selected the unique pseudokinase belonging to tyrosine kinase like (TKL) family for detailed structural and functional analysis in P. falciparum and P. berghei. The primary structure of PfpTKL lacks residues critical for kinase activity, supporting its annotation as a pseudokinase. The recombinant pTKL pseudokinase domain was able to bind ATP, but lacked catalytic activity as predicted. The sterile alpha motif (SAM) and RVxF motifs of PfpTKL were found to interact with the P. falciparum proteins serine repeat antigen 5 (SERA5) and protein phosphatase type 1 (PP1) respectively, suggesting that pTKL has a scaffolding role. Furthermore, we found that PP1c activity in a heterologous model was modulated in an RVxF-dependent manner. During the trophozoite stages, PbpTKL was exported to infected erythrocytes where it formed complexes with proteins involved in cytoskeletal organization or host cell maturation and homeostasis. Finally, genetic analysis demonstrated that viable strains obtained by genomic deletion or knocking down PbpTKL did not affect the course of parasite intra-erythrocytic development or gametocyte emergence, indicating functional redundancy during these parasite stages.

Yttrium oxide nanoparticle loaded scaffolds with enhanced cell adhesion and vascularization for tissue engineering applications

In situ tissue engineering is emerging as a novel approach in tissue engineering to repair damaged tissues by boosting the natural ability of the body to heal itself. This can be achieved by providing suitable signals and scaffolds that can augment cell migration, cell adhesion on the scaffolds and proliferation of endogenous cells that facilitate the repair. Lack of appropriate cell proliferation and angiogenesis are among the major issues associated with the limited success of in situ tissue engineering during in vivo studies. Exploitation of metal oxide nanoparticles such as yttrium oxide (Y2O3) nanoparticles may open new horizons in in situ tissue engineering by providing cues that facilitate cell proliferation and angiogenesis in the scaffolds. In this context, Y2O3 nanoparticles were synthesized and incorporated in polycaprolactone (PCL) scaffolds to enhance the cell proliferation and angiogenic properties. An optimum amount of Y2O3-containing scaffolds (1% w/w) promoted the proliferation of fibroblasts (L-929) and osteoblast-like cells (UMR-106). Results of chorioallantoic membrane (CAM) assay and the subcutaneous implantation studies in rats demonstrated the angiogenic potential of the scaffolds loaded with Y2O3 nanoparticles. Gene expression study demonstrated that the presence of Y2O3 in the scaffolds can upregulate the expression of cell proliferation and angiogenesis related biomolecules such as VEGF and EGFR. Obtained results demonstrated that Y2O3 nanoparticles can perform a vital role in tissue engineering scaffolds to promote cell proliferation and angiogenesis.