Cytoprotective effect of glutaraldehyde erythropoietin on HEK293 kidney cells after silver nanoparticle exposure

Kanidta Sooklert,1,2 Supreecha Chattong,3 Krissanapong Manotham,3 Chawikan Boonwong,1 I-yanut Klaharn,1 Depicha Jindatip,4 Amornpun Sereemaspun1,4 1Nanobiomedicine Laboratory, Department of Anatomy, Faculty of Medicine, 2Inter-Department Program of Biomedical Sciences, Faculty of Graduate School, Chulalongkorn University, 3Renal Unit, Department of Medicine, Lerdsin General Hospital, 4Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok, ThailandAbstract: The toxic effects from exposure to silver nanoparticles (AgNPs), which are broadly present in many consumer products, have long raised concerns. Many studies have focused on the mechanisms of nanosilver, which cause toxicity in human cells, but little is known about prevention of this type of injury. This study investigated the in vitro effects of glutaraldehyde erythropoietin (GEPO), a cytoprotective compound derived from erythropoietin, in terms of cell protection against AgNP-induced injury. HEK293 cells were pretreated with or without GEPO before administration of AgNPs. The protective effects of GEPO in this cell line were assessed by the percentage of viable cells, alterations of cell morphology, and the proliferative capability of the cells. In addition, we assessed the role of GEPO in lowering cellular oxidative stress and regulating expression of the anti-apoptotic protein Bcl2. The results showed rescue effects on the percentage of viable and proliferative cells among GEPO pretreated cells. Pretreatment with GEPO maintained the normal cell shape and ultrastructural morphology. Moreover, GEPO reduced the generation of reactive oxygen species in cells and activated expression of Bcl2, which are the major mechanisms in protection against cellular toxicity induced by AgNPs. In conclusion, our study showed that the cytotoxic effects from exposure to AgNPs can be prevented by GEPO. Keywords: glutaraldehyde erythropoietin, silver nanoparticles, cytoprotection, nanotoxicit

Doxorubicin-conjugated dexamethasone induced MCF-7 apoptosis without entering the nucleus and able to overcome MDR-1-induced resistance

Kamontip Chaikomon,1,2 Supreecha Chattong,1,3 Theerasak Chaiya,1 Danai Tiwawech,4 Yongsak Sritana-Anant,5 Amornpun Sereemaspun,6 Krissanapong Manotham1 1Molecular and Cellular Biology Unit, Department of Medicine, Lerdsin General Hospital, Bangkok, Thailand; 2Medical Sciences Program, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; 3EST Laboratory, SS Manufacturing, Nonthaburi, Thailand; 4Research Division, National Cancer Institute, Bangkok, Thailand; 5Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand; 6Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand Background: Doxorubicin (DOX) is the most widely used chemotherapeutic agent that has multimodal cytotoxicity. The main cytotoxic actions of DOX occur in the nucleus. The emergence of drug-resistant cancer cells that have the ability to actively efflux DOX out of the nucleus, and the cytoplasm has led to the search for a more effective derivative of this drug. Materials and methods: We created a new derivative of DOX that was derived via simple conjugation of the 3' amino group of DOX to the dexamethasone molecule. Results: Despite having a lower cytotoxic activity in MCF-7 cells, the conjugated product, DexDOX, exerted its actions in a manner that was different to that of DOX. DexDOX rapidly induced MCF-7 cell apoptosis without entering the nucleus. Further analysis showed that DexDOX increased cytosolic oxidative stress and did not interfere with the cell cycle. In addition, the conjugated product retained its cytotoxicity in multidrug resistance-1-overexpressing MCF-7 cells that had an approximately 16-fold higher resistance to DOX. Conclusion: We have synthesized a new derivative of DOX, which has the ability to overcome multidrug resistance-1-induced resistance. This molecule may have potential as a future chemotherapeutic agent. Keywords: doxorubicin, dexamethasone, drug-resistant tumor, bioconjugation, multidrug resistance, reactive oxygen specie

Angiogenesis Induction using Dental Pulp Stem Cells, A Collagen Scaffold Seeded in Pulp Chamber of Endodontically Treated Teeth and Subcutaneously Transplanted into Immunocompromised Mice

Background: Angiogenesis is an essential mechanism for repairing any damaged target tissues or organs in cell therapy because the process can provide the supplements of nutrients, oxygen, and other repair factors. Many studies have revealed the ability of stem cells to induce angiogenesis of vessels in various organs. According to previous studies, We postulated that dental pulp stem cells (DPSCs) may improve angiogenesis for dental tissue repair and hence the outcome of regeneration. Objective: We would like to evaluate the potential of DPSCs to induce an angiogenesis for dental tissue repair and regeneration. Methods: In this study we employed endodontically treated teeth as a model to evaluate the angiogenesis properties of dental pulp stem cells. DPSCs were isolated from human third molar impacted tooth samples and reconstituted in basement membrane matrix scaffold (Matri-Gel 3D) and injected in the pulp chamber of the prepared endodontically treated teeth. Transplantation of experimental and control teeth was performed subcutaneously in the dorsum of immunocompromised mice (NOD-SCID). Results: The vascular numbers in subcutaneous connective tissues of 4 week experimental mice, DPSCs and Matri-Gel scaffolds appeared visibly greater than those in the control group with Matri-Gel transplantation alone. Similar appearance was also found in the section of H-E stain of soft tissues of experimental teeth. Conclusions: This may suggest that DPSCs can induce the regeneration of vascular dependent tissues such as dental pulp regeneration in necrotic pulp from diseases and may have implications in the regeneration of revital tooth

Re-educating immunity in respiratory allergies: the potential for hematopoietic stem cell-mediated gene therapy

Respiratory allergies represent a significant disease burden worldwide affecting up to 300 million people globally. Medication and avoidance of known triggers do not address the underlying pathology. Traditional immunotherapies for allergy aim to reinstate immune homeostasis but require years of treatment and have poor long-term efficacy. Novel approaches, such as gene-engineered hematopoietic stem cell transplantation, induce profound antigen-specific tolerance in autoimmunity. Recent evidence shows this approach may also have therapeutic utility for allergy. Here, we review the mechanisms of antigen-specific tolerance and the potential of stem cell-mediated gene therapy to induce tolerance in allergic respiratory diseases