|Year : 2015 | Volume
| Issue : 1 | Page : 110
Cell- and gene- based therapeutics for periodontal regeneration
Keshava Abbayya1, Sameer Anil Zope1, Sanjay Naduwinmani2, Apurva Pisal1, Nagraj Puthanakar3
1 Department of Periodontology, School of Dental Sciences, Krishna Institute of Medical Sciences Deemed University, Karad, Maharashtra, India
2 Department of Orthodontics, Maratha Mandal Dental College, Belgaum, Karnataka, India
3 Department of Prosthodontics, A.C.P.M. Dental College, Dhule, Maharashtra, India
|Date of Submission||01-Oct-2014|
|Date of Acceptance||27-Apr-2015|
|Date of Web Publication||04-Nov-2015|
Department of Periodontology, School of Dental Sciences, Krishna Institute of Medical Sciences Deemed University, Karad, Maharashtra
Source of Support: None, Conflict of Interest: None
Periodontitis is a disease of the periodontium, characterized by loss of connective tissue attachment and supporting the alveolar bone. Therefore, to regenerate these lost tissues of the periodontium researchers have included a variety of surgical procedures including grafting materials growth factors and the use of barrier membranes, ultimately resulting into regeneration that is biologically possible but clinically unpredictable. Recently a newer approach of delivering DNA plasmids as therapeutic agents is gaining special attention and is called gene delivery method. Gene therapy being considered a novel approach have a potential to channel their signals in a very systematic and controlled manner thereby providing encoded proteins at all stages of tissue regeneration. The aim of this review was to enlighten a view on the application involving gene delivery and tissue engineering in periodontal regeneration.
Keywords: Gene, growth factors, periodontal regeneration, stem cells, tissue engineering, vectors
|How to cite this article:|
Abbayya K, Zope SA, Naduwinmani S, Pisal A, Puthanakar N. Cell- and gene- based therapeutics for periodontal regeneration. Int J Prev Med 2015;6:110
| Introduction|| |
Functional regeneration of periodontal apparatus is one of the most important aims of research in current periodontal regenerative therapy. The successful periodontal regeneration is a highly challenging tasks since careful histological assessment has revealed that allogenic bone grafts and even fresh autologous bone grafts, generally become encased in a dense fibrous connective tissue in periodontal defects.  Thus, a current challenge faced by clinicians is the complete, reliable and reproducible regeneration of the periodontal tissues, paying way to novel treatments that utilize a cell and gene-based approaches. This current review enlightens the clinicians with the application of cell and gene-based therapeutics in periodontal tissue regeneration.
| Periodontal tissue engineering|| |
The goal of the tissue engineering is to regenerate the functional tissue through a series of key events that occur during periodontal tissue formation and growth, by means of delivering signaling molecules, cells, and scaffold/matrix to periodontal defects. ,,
Signaling molecules therapeutics (protein-based therapeutics)
With the introduction of a new era of tissue engineering whereby biological mediators such as partially purified protein mixture from developing teeth (such as Emdogain® ) and growth factors from recombinant technology can be used to accelerate to periodontal regeneration. Apart from these biological mediators, platelet-rich plasma, which represents an autologous growth factor cocktail can be harvested from patients with minimal invasiveness and can be used for regenerative therapy.  However, the major drawbacks of this protein-based approach is the short half-life and also the instability of these proteins resulting in multiple delivery dosage and also delivery of milligram quantities of factor in routine clinical practices, thus leading to risk of unwanted side effects.  Limitations such as, limited control overdose administration, loss of bioactivity, nontargeted delivery and/or lack of availability has led to newer safe, and effective modes of periodontal regeneration through cell-based approach.
As stated first by Rudolph Virchow in 1855, "All cells come from other cells." Cell-based therapy involves the direct delivery of cells at the diseased site for tissue regeneration.  This approach is beneficial in periodontal tissue engineering because of following possibilities (i) direct participation of the transplanted cells in the regenerative process, (ii) genetic modification with therapeutic genes, and (iii) ability to get differentiated into a variety of periodontal tissue prototypes (bone, cementum, and periodontal ligament [PDL]).  Autologous cells appear to be a most appropriate source of cells for tissue engineering due to their high cellular activity. Whereas allogenic and xenogenic cells being heterogenous are potent agents for immunogenic reactions requiring immunosuppressive therapy when they are utilized for tissue engineering. ,,
Although six types of stem cells have been isolated in humans, they have been categorized mainly into embryonic stem cells (ES cells) and adult stem cells. 
Embryonic stem cells
Embryonic stem cells have an advantage of having greater differentiation potential when compared to multipotent or unipotent cells [Figure 1].  They exhibit stage-specific embryonic antigens 3 and 4, proteins TRA-1-60 and TRA-1-81, alkaline phosphatase (ALP), and also maintain their chromosomal length through the high expression of telomerase. 
Adult stem cells
Tissues such as skin, hematopoietic system, bone, and liver have the capacity to repair and renew indicating presence of stem or progenitor cells  [Figure 1]. Adult stem cells appear more mature with a finite lifespan and only multipotent differentiation capacity when compared to ES cells.  Hematopoietic stem cells were the first adult stem cells that were isolated from bone marrow.  Apart from hematopoietic adult nonhematopoietic stem cells also resides in the bone marrow microenvironment.  Which are known as bone marrow stromal stem cells or mesenchymal stem cells (MSCs) and characteristically express: CD44, CD105 (SH2; endoglin), CD106 vascular cell adhesion molecule-1, CD166, CD29, CD73 (SH3 and SH4), STRO-1, CD90 (Thy-1), CD117, and Sca-1. , Bone marrow is considered to be the main source of MSCs. Other than the bone marrow, MSCs can also be located in tissues such as adipose tissue, umbilical cord blood, chorionic villi of the placenta, amniotic fluid, peripheral blood, fetal liver, lung; and even in exfoliated deciduous teeth, dental pulp, and PDL. 
Induced pluripotent stem cells
In recent years, bone marrow, dental, and gingival epithelium-derived MSC have evolved as a promising new therapeutic approach for the regeneration of lost periodontal tissues.  Major factors inhibiting their use in routine clinical treatment are their limited accessibility and complex invasive methods to procure it. The possible reprogramming of adult somatic cells into a pluripotent stem cell state, through the addition of certain transcription factors, represents an appealing alternative to obtain from large source of adult-derived stem cells for use in regenerative medicine.  These cells have opened up the possibility of "fixing" a particular genotype (either normal or diseased) in pluripotent stem cells and thus attempting at developing robust in vitro disease models. The advantage of induced pluripotent stem cells (iPSC) over conventional MSC is that they can be obtained from any tissue type in the body, and also exhibit an unlimited growth capacity that can serve as an inexhaustible source of stem cells. 
Various animal studies have shown potential of different oral tissues to generate iPSC, including stem cells from dental pulp, exfoliated human deciduous teeth, apical papilla, oral mucosa, third molar mesenchymal stromal cells, PDL fibroblasts, and gingival fibroblasts. Most of these in vitro and in vivo studies were conducted using mice iPSC. However, recently, a study has shown successful induction of integration-free human urine iPSCs into the intact epithelial sheet, which differentiated into ameloblasts in a tooth-like structure thus indicating a possible role of human iPSCs in tooth regeneration. 
Gene delivery-based therapeutics
Gene delivery-based therapeutics is based on transferring of genetic materials to alter specific genes in individual's cells to produce a therapeutic effect.  To overcome the problems associated with protein and cell-based approach, gene therapy has been developed which modifies function of cells to provide long-term exposure of multiple growth factors and thereby maintains constant protein levels at the site of the defect. ,,
| Vectors for gene delivery|| |
Gene delivery vectors are divided into two groups: Viral and nonviral vectors. 
- Adenoviral vectors (adeno-associated virus [AAV]): These vectors possess a characteristic feature of (a) infecting a variety of cell types (b) being purified at high titers and (c) results in a high level of gene expression.  Some of the disadvantages of adenovirus include the inability to express the gene for a long-term and also results in inducing host immunogenic response. To overcome the problems involving immunogenicity, the newer generation that is the second generation of adeno vectors have been introduced 
- Retroviral and lentiviral vectors: These vectors have the advantage over adenoviral vectors due to their low-grade immunogenicity and also for expressing genes for a long-term. They have a good capability of delivering genes to stem cells and also cytotoxic genes to cancer cells 
- AAVs: AAV known for their superior safety feature due to their nonimmunogenic nature and are thought to be useful in periodontal regeneration.  They carry a unique character of expressing and delivering gene throughout life in both dividing and nondividing cells.
Nonviral vectors consist of naked DNA alone or in conjunction with a carrier. They are superior when compared to viral vectors due to their nonimmunogenicity, low toxicity, and less likely of being introduced into the host cell genome.  These vectors also have low gene transfer efficiency and in some cases in vivo instability and transient gene expression. ,
| Gene delivery approaches|| |
Genetic alteration of somatic cells could be achieved by manipulating the cells residing naturally within the individual's body that is, in vivo approach or it could be by manipulating the cells obtained from individual's body and subsequently returning it to the host that is, ex vivo approach.
In vivo approaches
In In vivo approach, DNA plasmids are directly injected into desired sites. These injected gene constructs are taken by the host cells and then start to produce the encoded protein for therapeutic purpose. 
Ex vivo approaches
In ex vivo approach, a specific population of cells (example PDL cells) is obtained from tissues, followed by transferring of genes to these cells under in vitro conditions. This gene coded cells are subsequently transferred back into periodontal defects. Thus, resulting into the selective genetic manipulation of the desired cell type and the regeneration of respective lost tissues.
| Target genes for periodontal tissue engineering|| |
Transforming growth factor-beta family members and bone morphogenetic proteins
Bone morphogenetic proteins (BMPs) and transforming growth factor-betas (TGF-βs) belong to the same peptide superfamily, they are pleiotropic factors, which play an important role in the control of somatic tissue development and renewal.  TGF-1 stimulates apposition of bone matrix and also bone cell replication and increases proliferation in cementoblasts.  BMP-3 and BMP-7 (i.e., osteogenic protein-1) play an important role in cementogenesis and the assembly of PDL,  whereas BMP-2 and BMP-7 stimulate human PDL fibroblasts to differentiate into osteoblastic phenotypes by increasing the production of ALP, resulting in an accelerated bone regeneration.
Platelet derived growth factors
Platelet-derived growth factor (PDGF) is an active growth factor, which is a product of two distinct genes PDGF-A and PDGF-B. PDGF stimulates DNA synthesis and cell replication in osteoblasts,  as well as increases bone collagen synthesis and the rate of bone matrix apposition. 
Insulin-like growth factor-1
These biologic mediators having single-chain peptides are of two types insulin-like growth factor-1 (IGF-1) and IGF-2 and are primarily involved in periodontal wound healing and regeneration by affecting the PDL cell turnover.  IGF-1 stimulates human PDL fibroblast proliferation in a dose- and time-dependent manner  and along with PDGF-BB and TGF-β induce periodontal soft and hard tissues regeneration. 
The sonic hedgehog gene also encodes a regulator protein of embryonic osteogenesis and the repair of bone fractures, which may also have significant effects on periodontal bone regeneration and is found during embryogenesis. 
These are a family of 19 secreted glycoproteins that play a role in embryonic development and postdevelopmental physiology by regulation of cell proliferation, differentiation, and apoptosis. The role of wingless (WNTs) in homeostasis and regeneration of periodontal tissues remains largely unknown. Since the utilization of WNTs is still in its infancy, further studies are required to prove its role in periodontal regeneration. 
| Gene Delivery Systems/Devices|| |
A controlled gene delivery systems, which act as localized depot of genes, provide an extended sustained release of genes, delivering controlled maintenance of the therapeutic level of encoded proteins. They also limit the DNA degradation in the nuclease rich extra-cellular environment in vivo. A wide range of synthetic polymers, natural origin polymers, composites, and inorganic materials may be used as platforms for the delivery of genes naked plasmid DNA or a viral particle. 
The function of particulate systems for gene delivery was promptly considered as a mode to protect DNA during tissue regeneration and to provide adequate control over release rate. After releasing, DNA can transfect the cells at the delivery site. Hence, much attention has been focused on such as Food and Drug Administration approved poly (lactic-co-glycolic acid) (PLGA), for the encapsulation of genes.  Other materials used to encapsulate DNA are natural chitosan  and gelatin. 
Polymeric hydrogel systems
Polymeric hydrogel systems are formed by cross-linking of a natural or synthetic polymer. Commonly used hydrogels are poly (ethylene glycol), polylactic acid (PLA), polyglycolic acid, PLGA, and copolymers poly (epsilon-caprolactone)-poly (ethylene oxide)-poly (epsilon-caprolactone). 
These delivery systems are based on GTR technology, cell scaffolding, and drug delivery of growth factors and/or genes. Currently used scaffolds include (i) porous collagen/chitosan scaffold, (ii) gelatin sponge system, (iii) biodegradable PLA barrier device (Atrisorb), (iv) space-providing macroporous expanded polytetrafluoroethylene device, and (v) hydroxyapatite-based biomimetic matrix. 
Gene delivery for host modulation of periodontal disease
Major cause of periodontal destruction in periodontal disease is the host response against periodontal pathogenic bacteria. New approaches have been developed to target host-derived inflammatory mediators such as MMPs, cathepsins, and other osteoclast-derived factors leading to bone resorption.  Gene therapy has the potential for long-term maintenance of therapeutic proteins. Gene therapy using AAV to deliver the tumor necrosis factor receptor-immunoglobulin Fc (TNFR: Fc) fusion gene to experimental Porphyromonas gingivalis - lipopolysaccharide-mediated bone loss resulted in sustained therapeutic levels of serum TNFR protein for ≥3 months, and inhibition of P. gingivalis - lipopolysaccharide-mediated bone loss.  Patil et al.  showed that increased expression of tristetraprolin, (a key cytokine-regulating RNA-binding protein) by an adenoviral vector significantly reduces the levels of interleukin-6, TNF-α, and prostaglandin E2 in vitro which in turn may reduce inflammation-induced bone loss in an experimental periodontitis model. Recently, an in vivo study demonstrated that mitogen-activated protein kinase phosphatase-1 has potential to prevent alveolar bone loss.  These findings suggest the possible role of gene-based approach in the modulating host response to periodontal pathogens.
| Conclusions|| |
Genetically modified cell therapy is considered to be the recent advances in periodontal regeneration but with its limitations it has rarely found its way into clinical practice. Interdisciplinary approaches are needed to develop effective strategies to move from repair to regeneration involving clinicians as well as cell biologists and material scientists. Thus, cell and gene-based approaches may complement each other in the predictable regeneration of the lost periodontal apparatus by overcoming the limitations of current treatment approaches.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Elangovan S, Srinivasan S, Ayilavarapu S. Novel regenerative strategies to enhance periodontal therapy outcome. Expert Opin Biol Ther 2009;9:399-410.
Kao RT, Conte G, Nishimine D, Dault S. Tissue engineering for periodontal regeneration. J Calif Dent Assoc 2005;33:205-15.
Ramseier CA, Abramson ZR, Jin Q, Giannobile WV. Gene therapeutics for periodontal regenerative medicine. Dent Clin North Am 2006;50:245-63, ix.
Nakahara T. A review of new developments in tissue engineering therapy for periodontitis. Dent Clin North Am 2006;50:265-76, ix-x.
Chen FM, Shelton RM, Jin Y, Chapple IL. Localized delivery of growth factors for periodontal tissue regeneration: Role, strategies, and perspectives. Med Res Rev 2009;29:472-513.
Liu Y, Zheng Y, Ding G, Fang D, Zhang C, Bartold PM, et al.
Periodontal ligament stem cell-mediated treatment for periodontitis in miniature swine. Stem Cells 2008;26:1065-73.
Pera MF, Cooper S, Mills J, Parrington JM. Isolation and characterization of a multipotent clone of human embryonal carcinoma cells. Differentiation 1989;42:10-23.
Griffiths MJ, Bonnet D, Janes SM. Stem cells of the alveolar epithelium. Lancet 2005;366:249-60.
Silvério KG, Benatti BB, Casati MZ, Sallum EA, Nociti FH Jr. Stem cells: Potential therapeutics for periodontal regeneration. Stem Cell Rev 2008;4:13-9.
Vats A, Bielby RC, Tolley NS, Nerem R, Polak JM. Stem cells. Lancet 2005;366:592-602.
Lin NH, Gronthos S, Bartold PM. Stem cells and periodontal regeneration. Aust Dent J 2008;53:108-21.
Becker AJ, Mcculloch EA, TILL JE. Cytological demonstration of the clonal nature of spleen colonies derived from transplanted mouse marrow cells. Nature 1963;197:452-4.
Friedenstein AJ, Petrakova KV, Kurolesova AI, Frolova GP. Heterotopic of bone marrow. Analysis of precursor cells for osteogenic and hematopoietic tissues. Transplantation 1968;6:230-47.
Gronthos S, Zannettino AC, Hay SJ, Shi S, Graves SE, Kortesidis A, et al.
Molecular and cellular characterisation of highly purified stromal stem cells derived from human bone marrow. J Cell Sci 2003;116:1827-35.
Boiret N, Rapatel C, Veyrat-Masson R, Guillouard L, Guérin JJ, Pigeon P, et al.
Characterization of nonexpanded mesenchymal progenitor cells from normal adult human bone marrow. Exp Hematol 2005;33:219-25.
Otsu K, Kumakami-Sakano M, Fujiwara N, Kikuchi K, Keller L, Lesot H, et al.
Stem cell sources for tooth regeneration: Current status and future prospects. Front Physiol 2014;5:36.
Hynes K, Menicanin D, Han J, Marino V, Mrozik K, Gronthos S, et al.
Mesenchymal stem cells from iPS cells facilitate periodontal regeneration. J Dent Res 2013;92:833-9.
Hynes K, Gronthos S, Bartold PM. iPSC for dental tissue regeneration. Curr Oral Health Rep 2014;1:9-15.
Rios HF, Lin Z, Oh B, Park CH, Giannobile WV. Cell- and gene-based therapeutic strategies for periodontal regenerative medicine. J Periodontol 2011;82:1223-37.
Stiehler M, Duch M, Mygind T, Li H, Ulrich-Vinther M, Modin C, et al.
Optimizing viral and non-viral gene transfer methods for genetic modification of porcine mesenchymal stem cells. Adv Exp Med Biol 2006;585:31-48.
Campos SK, Barry MA. Current advances and future challenges in Adenoviral vector biology and targeting. Curr Gene Ther 2007;7:189-204.
Franceschi RT. Biological approaches to bone regeneration by gene therapy. J Dent Res 2005;84:1093-103.
Tai CK, Kasahara N. Replication-competent retrovirus vectors for cancer gene therapy. Front Biosci 2008;13:3083-95.
Snyder RO, Francis J. Adeno-associated viral vectors for clinical gene transfer studies. Curr Gene Ther 2005;5:311-21.
Heyde M, Partridge KA, Oreffo RO, Howdle SM, Shakesheff KM, Garnett MC. Gene therapy used for tissue engineering applications. J Pharm Pharmacol 2007;59:329-50.
Ikada Y. Challenges in tissue engineering. J R Soc Interface 2006;3:589-601.
Dereka XE, Markopoulou CE, Vrotsos IA. Role of growth factors on periodontal repair. Growth Factors 2006;24:260-7.
Gao J, Symons AL, Bartold PM. Expression of transforming growth factor-beta 1 (TGF-beta1) in the developing periodontium of rats. J Dent Res 1998;77:1708-16.
Thomadakis G, Ramoshebi LN, Crooks J, Rueger DC, Ripamonti U. Immunolocalization of Bone Morphogenetic Protein-2 and -3 and Osteogenic Protein-1 during murine tooth root morphogenesis and in other craniofacial structures. Eur J Oral Sci 1999;107:368-77.
Canalis E, McCarthy TL, Centrella M. Effects of platelet-derived growth factor on bone formation in vitro
. J Cell Physiol 1989;140:530-7.
Pfeilschifter J, Oechsner M, Naumann A, Gronwald RG, Minne HW, Ziegler R. Stimulation of bone matrix apposition in vitro
by local growth factors: A comparison between insulin-like growth factor I, platelet-derived growth factor, and transforming growth factor beta. Endocrinology 1990;127:69-75.
Han X, Amar S. IGF-1 signaling enhances cell survival in periodontal ligament fibroblasts vs. gingival fibroblasts. J Dent Res 2003;82:454-9.
Palioto DB, Coletta RD, Graner E, Joly JC, de Lima AF. The influence of enamel matrix derivative associated with insulin-like growth factor-I on periodontal ligament fibroblasts. J Periodontol 2004;75:498-504.
Howell TH, Fiorellini JP, Paquette DW, Offenbacher S, Giannobile WV, Lynch SE. A phase I/II clinical trial to evaluate a combination of recombinant human platelet-derived growth factor-BB and recombinant human insulin-like growth factor-I in patients with periodontal disease. J Periodontol 1997;68:1186-93.
Ghali S, Dempsey MP, Jones DM, Grogan RH, Butler PE, Gurtner GC. Plastic surgical delivery systems for targeted gene therapy. Ann Plast Surg 2008;60:323-32.
Díez S, Tros de Ilarduya C. Versatility of biodegradable poly (D, L-lactic-co-glycolic acid) microspheres for plasmid DNA delivery. Eur J Pharm Biopharm 2006;63:188-97.
Dass CR, Contreras KG, Dunstan DE, Choong PF. Chitosan microparticles encapsulating PEDF plasmid demonstrate efficacy in an orthotopic metastatic model of osteosarcoma. Biomaterials 2007;28:3026-33.
Young S, Wong M, Tabata Y, Mikos AG. Gelatin as a delivery vehicle for the controlled release of bioactive molecules. J Control Release 2005;109:256-74.
Chen FM, Ma ZW, Wang QT, Wu ZF. Gene delivery for periodontal tissue engineering: Current knowledge-future possibilities. Curr Gene Ther 2009;9:248-66.
Giannobile WV. Host-response therapeutics for periodontal diseases. J Periodontol 2008;798 Suppl: 1592-600.
Cirelli JA, Park CH, MacKool K, Taba M Jr, Lustig KH, Burstein H, et al.
AAV2/1-TNFR: Fc gene delivery prevents periodontal disease progression. Gene Ther 2009;16:426-36.
Patil CS, Liu M, Zhao W, Coatney DD, Li F, VanTubergen EA, et al.
Targeting mRNA stability arrests inflammatory bone loss. Mol Ther 2008;16:1657-64.
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