Biomimetic Extracellular Matrix Nanofibers Electrospun with Calreticulin Promote Synergistic Activity for Tissue Regeneration

Epithelial-Mesenchymal Transition of Cancer Cells on Micropillar Arrays

Epithelial-mesenchymal transition (EMT) is critical for tumor invasion and many other cell-relevant processes. While much progress has been made about EMT, no report concerns the EMT of cells on topological biomaterial interfaces with significant nuclear deformation. Herein, we prepared a poly(lactide-co-glycolide) micropillar array with an appropriate dimension to enable significant deformation of cell nuclei and examined EMT of a human lung cancer epithelial cell (A549). We show that A549 cells undergo serious nuclear deformation on the micropillar array. The cells express more E-cadherin and less vimentin on the micropillar array than on the smooth surface. After transforming growth factor-β1 (TGF-β1) treatment, the expression of E-cadherin as an indicator of the epithelial phenotype is decreased and the expression of vimentin as an indicator of the mesenchymal phenotype is increased for the cells both on smooth surfaces and on micropillar arrays, indicating that EMT occurs even when the cell nuclei are deformed and the culture on the micropillar array more enhances the expression of vimentin. Expression of myosin phosphatase targeting subunit 1 is reduced in the cells on the micropillar array, possibly affecting the turnover of myosin light chain phosphorylation and actin assembly; this makes cells on the micropillar array prefer the epithelial-like phenotype and more sensitive to TGF-β1. Overall, the micropillar array exhibits a promoting effect on the EMT.

The Biologic IRL201805 Alters Immune Tolerance Leading to Prolonged Pharmacodynamics and Efficacy in Rheumatoid Arthritis Patients

A homologue of binding immunoglobulin protein/BiP-IRL201805 alters the function of immune cells in pre-clinical in vivo and in vitro studies. The aim of the study was to select biomarkers that clearly delineate between RA patients who respond to IRL201805 and placebo patients and reveal the immunological mode of action of IRL201805 driving the extended pharmacodynamics observed in responding patients. Biomarkers that distinguished between responding patients and placebo patients included downregulation of serum interferon-γ and IL-1β; upregulation of anti-inflammatory mediators, serum soluble CTLA-4, and intracellular monocyte expression of IDO; and sustained increased CD39 expression on CD3+CD4+CD25hi CD127lo regulatory T cells. In the responding patients, selected biomarkers verified that the therapeutic effect could be continuous for at least 12 weeks post-infusion. In secondary co-culture, pre-infusion PBMCs cultured 1:1 with autologous PBMCs, isolated at later time-points during the trial, showed significantly inhibited IL-6 and IL-1β production upon anti-CD3/CD28 stimulation demonstrating IRL201805 alters the function of immune cells leading to prolonged pharmacodynamics confirmed by biomarker differences. IRL201805 may be the first of a new class of biologic drug providing long-term drug-free therapy in RA.

Calreticulin accelerates corneal wound closure and mitigates fibrosis: Potential therapeutic applications

The processes involved in regeneration of cutaneous compared to corneal tissues involve different intrinsic mechanisms. Importantly, cutaneous wounds involve healing by angiogenesis but vascularization of the cornea obscures vision. Previous studies showed that topically applied calreticulin (CALR) healed full-thickness excisional animal wounds by a tissue regenerative process markedly enhancing repair without evoking angiogenesis. In the current study, the application of CALR in a rabbit corneal injury model: (1) accelerated full wound closure by 3 days (2) accelerated delayed healing caused by corticosteroids, routinely used to prevent post-injury inflammation, by 6 days and (3) healed wounds without vascularization or fibrosis/hazing. In vitro, CALR stimulated proliferation of human corneal epithelial cells (CE) and corneal stromal cells (keratocytes) by 1.5-fold and 1.4-fold, respectively and induced migration of CE cells and keratocytes, by 72% and 85% compared to controls of 44% and 59%, respectively. As a marker of decreased fibrosis, CALR treated corneal wounds showed decreased immunostaining for α-smooth muscle actin (α-SMA) by keratocytes and following CALR treatment in vitro, decreased the levels of TGF-β2 in human CE cells and α-SMA in keratocytes. CALR has the potential to be a novel therapeutic both, to accelerate corneal healing from various injuries and in conjunction with corticosteroids.

Malate-Based Biodegradable Scaffolds Activate Cellular Energetic Metabolism for Accelerated Wound Healing

The latest advancements in cellular bioenergetics have revealed the potential of transferring chemical energy to biological energy for therapeutic applications. Despite efforts, a three-dimensional (3D) scaffold that can induce long-term bioenergetic effects and facilitate tissue regeneration remains a big challenge. Herein, the cellular energetic metabolism promotion ability of l-malate, an important intermediate of the tricarboxylic acid (TCA) cycle, was proved, and a series of bioenergetic porous scaffolds were fabricated by synthesizing poly(diol l-malate) (PDoM) prepolymers via a facial one-pot polycondensation of l-malic acid and aliphatic diols, followed by scaffold fabrication and thermal-cross-linking. The degradation products of the developed PDoM scaffolds can regulate the metabolic microenvironment by entering mitochondria and participating in the TCA cycle to elevate intracellular adenosine triphosphate (ATP) levels, thus promoting the cellular biosynthesis, including the production of collagen type I (Col1a1), fibronectin 1 (Fn1), and actin alpha 2 (Acta2/α-Sma). The porous PDoM scaffold was demonstrated to support the growth of the cocultured mesenchymal stem cells (MSCs) and promote their secretion of bioactive molecules [such as vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1), and basic fibroblast growth factor (bFGF)], and this stem cells-laden scaffold architecture was proved to accelerate wound healing in a critical full-thickness skin defect model on rats.

Electrospun fibers for the treatment of skin diseases

Skin diseases are among the most common diseases in the global population and with the growth of the aging population, they represent an increasing burden to healthcare systems worldwide. Even though they are rarely life-threatening, the suffering for those affected is high due to the visibility and physical discomfort related to these diseases. Typical symptoms of skin diseases include an inflamed, swollen or itchy skin, and therefore, there is a high demand for effective therapy options. In recent years, electrospinning has attracted considerable interest in the field of drug delivery. The technique allows producing multifunctional drug-loaded fibrous patches from various natural and synthetic polymers with fiber diameters in the nano- and micrometer range, suitable for the treatment of a wide variety of skin diseases. The great potential of electrospun fiber patches not only lies in their tunable drug release properties and the possibility to entrap a variety of therapeutic compounds, but they also provide physical and mechanical protection to the impaired skin area, exhibit a high surface area, allow gas exchange, absorb exudate due to their porous structure and are cytocompatible and biodegradable. In the case of wound healing, cell adhesion is promoted due to the resemblance of the electrospun fibers to the structure of the native extracellular matrix. This review gives an overview of the potential applications of electrospun fibers in skin therapy. In addition to the treatment of bacterial, diabetic and burn wounds, focus is placed on inflammatory diseases such as atopic dermatitis and psoriasis, and therapeutic options for the treatment of skin cancer, acne vulgaris and herpes labialis are discussed. While we aim to emphasize the great potential of electrospun fiber patches for the treatment of skin diseases with this review paper, we also highlight challenges and limitations of current research in the field.

Gingival Fibroblasts Are Sensitive to Oral Cell Lysates Indicated by Their IL11 Expression

Damaged cells that appear as a consequence of invasive dental procedures or in response to dental materials are supposed to release damage-associated signals. These damage-associated signals not only support tissue regeneration but might also contribute to unwanted fibrosis. The aim of this study was to identify a molecular target that reflects how fibroblasts respond to necrotic oral tissue cells. To simulate the cell damage, we prepared necrotic cell lysates by sonication of the osteocytic cell line IDG-SW3 and exposed them to gingival fibroblasts. RNAseq revealed a moderate increase in IL11 expression in the gingival fibroblasts, a pleiotropic cytokine involved in fibrosis and inflammation, and also in regeneration following trauma. Necrotic lysates of the human squamous carcinoma cell lines HSC2 and TR146, as well as of gingival fibroblasts, however, caused a robust increase in IL11 expression in the gingival fibroblasts. Consistently, immunoassay revealed significantly increased IL11 levels in the gingival fibroblasts when exposed to the respective lysates. Considering that IL11 is a TGF-β target gene, IL11 expression was partially blocked by SB431542, a TGF-β receptor type I kinase inhibitor. Moreover, lysates from the HSC2, TR146, and gingival fibroblasts caused a moderate smad2/3 nuclear translocation in the gingival fibroblasts. Taken together and based on IL11 expression, our findings show that fibroblasts are sensitive to damaged oral tissue cells.

Calreticulin: a multifunctional protein with potential therapeutic applications for chronic wounds

Calreticulin is recognized as a multifunctional protein that serves an essential role in diverse biological processes that include wound healing, modification and folding of proteins, regulation of the secretory pathway, cell motility, cellular metabolism, protein synthesis, regulation of gene expression, cell cycle regulation and apoptosis. Although the role of calreticulin as an endoplasmic reticulum-chaperone protein has been well described, several studies have demonstrated calreticulin to be a highly versatile protein with an essential role during wound healing. These features make it an ideal molecule for treating a complex, multifactorial diseases that require fine tuning, such as chronic wounds. Indeed, topical application of recombinant calreticulin to wounds in multiple models of wound healing has demonstrated remarkable pro-healing effects. Among them include enhanced keratinocyte and fibroblast migration and proliferation, induction of extracellular matrix proteins, recruitment of macrophages along with increased granulation tissue formation, all of which are important functions in promoting wound healing that are deregulated in chronic wounds. Given the high degree of diverse functions and pro-healing effects, application of exogenous calreticulin warrants further investigation as a potential novel therapeutic option for chronic wound patients. Here, we review and highlight the significant effects of topical application of calreticulin on enhancing wound healing and its potential as a novel therapeutic option to shift chronic wounds into healing, acute-like wounds.

Calreticulin: Endoplasmic reticulum Ca2+ gatekeeper

Endoplasmic reticulum (ER) luminal Ca2+ is vital for the function of the ER and regulates many cellular processes. Calreticulin is a highly conserved, ER-resident Ca2+ binding protein and lectin-like chaperone. Over four decades of studying calreticulin demonstrate that this protein plays a crucial role in maintaining Ca2+ supply under different physiological conditions, in managing access to Ca2+ and how Ca2+ is used depending on the environmental events and in making sure that Ca2+ is not misused. Calreticulin plays a role of ER luminal Ca2+ sensor to manage Ca2+ -dependent ER luminal events including maintaining interaction with its partners, Ca2+ handling molecules, substrates and stress sensors. The protein is strategically positioned in the lumen of the ER from where the protein manages access to and distribution of Ca2+ for many cellular Ca2+ -signalling events. The importance of calreticulin Ca2+ pool extends beyond the ER and includes influence of cellular processes involved in many aspects of cellular pathophysiology. Abnormal handling of the ER Ca2+ contributes to many pathologies from heart failure to neurodegeneration and metabolic diseases.

Electrospinning Nanofibers as a Dressing to Treat Diabetic Wounds

Globally, diabetic mellitus (DM) is a common metabolic disease that effectively inhibits insulin production, destroys pancreatic β cells, and consequently, promotes hyperglycemia. This disease causes complications, including slowed wound healing, risk of infection in wound areas, and development of chronic wounds all of which are significant sources of mortality. With an increasing number of people diagnosed with DM, the current method of wound healing does not meet the needs of patients with diabetes. The lack of antibacterial ability and the inability to sustainably deliver necessary factors to wound areas limit its use. To overcome this, a new method of creating wound dressings for diabetic patients was developed using an electrospinning methodology. The nanofiber membrane mimics the extracellular matrix with its unique structure and functionality, owing to which it can store and deliver active substances that greatly aid in diabetic wound healing. In this review, we discuss several polymers used to create nanofiber membranes and their effectiveness in the treatment of diabetic wounds.