Functionalized nanoparticles containing MKP-1 agonists reduce periodontal bone loss

A new direction in periodontitis treatment: biomaterial-mediated macrophage immunotherapy

Periodontitis is a chronic inflammation caused by a bacterial infection and is intimately associated with an overactive immune response. Biomaterials are being utilized more frequently in periodontal therapy due to their designability and unique drug delivery system. However, local and systemic immune response reactions driven by the implantation of biomaterials could result in inflammation, tissue damage, and fibrosis, which could end up with the failure of the implantation. Therefore, immunological adjustment of biomaterials through precise design can reduce the host reaction while eliminating the periodontal tissue's long-term chronic inflammation response. It is important to note that macrophages are an active immune system component that can participate in the progression of periodontal disease through intricate polarization mechanisms. And modulating macrophage polarization by designing biomaterials has emerged as a new periodontal therapy technique. In this review, we discuss the role of macrophages in periodontitis and typical strategies for polarizing macrophages with biomaterials. Subsequently, we discuss the challenges and potential opportunities of using biomaterials to manipulate periodontal macrophages to facilitate periodontal regeneration.

Mussel-Based Biomimetic Strategies in Musculoskeletal Disorder Treatment: From Synthesis Principles to Diverse Applications

Musculoskeletal disorders are the second leading cause of disability worldwide, posing a huge global burden to the public sanitation system. Currently, tissue engineering-based approaches act as effective strategies, which are, however, challenging in limited application scenarios. Mussel-based biomimetic materials, exhibit numerous unique properties such as intense adhesion, biocompatibility, moisture resistance, and injectability, to name only a few, and have attracted extensive research interest. In particular, featuring state-of-the-art properties, mussel-inspired biomaterials have been widely explored in innumerable musculoskeletal disorder treatments including osteochondral defects, osteosarcoma, osteoarthritis, ligament rupture, and osteoporosis. Nevertheless, a comprehensive and timely discussion of their applications in musculoskeletal disorders is insufficient. In this review, we emphasize on (1) the main categories and characteristics of mussel foot proteins and their fundamental mechanisms for the spectacular adhesion in mussels; (2) the diverse synthetic methods and modification of various polymers; and (3) the emerging applications of mussel-biomimetic materials, the future perspectives, and challenges, especially in the area of musculoskeletal disorder. We envision that this review will provide a unique and insightful perspective to improve the development of a new generation of mussel biomimetic strategies.

Polymeric Nanotechnologies for the Treatment of Periodontitis: A Chronological Review

Periodontitis is a chronic infectious and inflammatory disease of periodontal tissues estimated to affect 70 - 80 % of all adults. At the same time, periodontium, the site of periodontal pathologies, is an extraordinarily complex plexus of soft and hard tissues, the regeneration of which using even the most advanced forms of tissue engineering continues to be a challenge. Nanotechnologies, meanwhile, have provided exquisite tools for producing biomaterials and pharmaceutical formulations capable of elevating the efficacies of standard pharmacotherapies and surgical approaches to whole new levels. A bibliographic analysis provided here demonstrates a continuously increasing research output of studies on the use of nanotechnologies in the management of periodontal disease, even when they are normalized to the total output of studies on periodontitis. The great majority of biomaterials used to tackle periodontitis, including those that pioneered this interesting field, have been polymeric. In this article, a chronological review of polymeric nanotechnologies for the treatment of periodontitis is provided, focusing on the major conceptual innovations since the late 1990s, when the first nanostructures for the treatment of periodontal diseases were fabricated. In the opening sections, the etiology and pathogenesis of periodontitis and the anatomical and histological characteristics of the periodontium are being described, along with the general clinical manifestations of the disease and the standard means of its therapy. The most prospective chemistries in the design of polymers for these applications are also elaborated. It is concluded that the amount of innovation in this field is on the rise, despite the fact that most studies are focused on the refinement of already established paradigms in tissue engineering rather than on the development of revolutionary new concepts.

7-Ketocholesterol-Induced Micro-RNA-107-5p Increases Number and Activity of Osteoclasts by Targeting MKP1

Osteoclasts (OCs), which are responsible for bone resorption, play a critical role in cholesterol-induced bone loss and recent studies have suggested that various micro-RNAs (miRs) contribute to modulating OCs. We hypothesized that 7-ketocholesterol (7-KC), a metabolite responsible for cholesterol-induced bone loss, induces miR-107-5p, which affects OCs. Overexpression and knock-down of miR-107-5p were performed using miR-107-5p mimic and anti-miR-107-5p, respectively. The effects of miR-107-5p on OCs were analyzed by tartrate-resistant alkaline phosphatase staining, qPCR, and Western blot. MiR-107-5p was upregulated after 7-KC exposure in receptor activator of nuclear factor kappa-Β ligand-stimulated OCs. Furthermore, miR-107-5p upregulation was also observed in tibiae from an atherogenic diet-fed mice compared with mice fed with a normal diet. MiR-107-5p overexpression enhanced the area and number of OCs, whereas inhibiting the endogenous expression of miR-107-5p generated by 7-KC had the opposite effect. Among the possible candidates, mitogen-activated protein kinase phosphatase-1, a stress-responsive dual-specificity phosphatase that inactivates mitogen-activated protein kinase (MKP1), has been proven to be a target gene of miR-107-5p, as demonstrated by the direct interaction between miR-107-5p and the 3'-untranslated region of MKP1. Collectively, our findings demonstrate that 7-KC-induced miR-107-5p promotes differentiation and function of OCs by downregulating MKP1.

Engineering Polymeric Nanosystems against Oral Diseases

Nanotechnology and nanoparticles (NPs) are at the forefront of modern research, particularly in the case of healthcare therapeutic applications. Polymeric NPs, specifically, hold high promise for these purposes, including towards oral diseases. Careful optimisation of the production of polymeric NPs, however, is required to generate a product which can be easily translated from a laboratory environment to the actual clinical usage. Indeed, considerations such as biocompatibility, biodistribution, and biodegradability are paramount. Moreover, a pre-clinical assessment in adequate in vitro, ex vivo or in vivo model is also required. Last but not least, considerations for the scale-up are also important, together with an appropriate clinical testing pathway. This review aims to eviscerate the above topics, sourcing at examples from the recent literature to put in context the current most burdening oral diseases and the most promising polymeric NPs which would be suitable against them.

miR-221-3p and miR-222-3p downregulation promoted osteogenic differentiation of bone marrow mesenchyme stem cells through IGF-1/ERK pathway under high glucose condition

OBJECTIVE

This study aims to investigate the roles of miR-221-3p and miR-222-3p in the regulation of osteogenic differentiation of bone marrow mesenchyme stem cells (BMSCs) under high glucose condition.

MATERIALS AND METHODS

The expreesions of miR-221-3p, miR-222-3p and insulin-like growth factor 1 (IGF-1) were detected by qRT-PCR. The protein levels of osteoblast-related proteins (Osterix, Runx-2 and Osteopontin) were detected by western blot. Whether miR-221-3p and miR-222-3p can target IGF-1 was assessed by dual luciferase reporter gene assay.

RESULTS

miR-221-3p and miR-222-3p were up-regulated in the mandibles of diabetic rats and BMSCs cultured in high glucose condition. Silencing miR-221-3p or/ and miR-222-3p increased ALP activity and up-regulated osteoblast-related protein levels, and the simultaneous silence the two miRNAs showed stronger effects on ALP activity and osteoblast-related protein levels. Next, we confirmed that miR-221-3p and miR-222-3p both targeted IGF-1 and cooperatively regulated its expression. Besides, miR-221-3p and miR-222-3p regulated ERK activation through IGF-1. Silencing miR-221-3p and miR-222-3p promoted osteogenic differentiation of BMSCs through IGF-1 under high glucose condition.

CONCLUSION

miR-221-3p and miR-222-3p inhibited osteogenic differentiation of BMSCs via IGF-1/ERK pathway under high glucose condition.

Emerging Nanotechnology in Non-Surgical Periodontal Therapy in Animal Models: A Systematic Review

Periodontitis is one of the most prevalent inflammatory diseases. Its treatment, mostly mechanical and non-surgical, shows limitations. The aim of this systematic review was to investigate the effect of nanoparticles as a treatment alone in non-surgical periodontal therapy in animal models. A systematic search was conducted in Medline/PubMed, Web of Science, The Cochrane Library and Science Direct. The eligibility criteria were: studies (i) using nanoparticles as chemotherapeutic agent or as delivery system; (ii) including preclinical controlled animal model (experimental periodontitis); (iii) reporting alveolar bone loss; (iv) written in English; and (v) published up to June 2019. Risk of bias was evaluated according to the SYstematic Review Centre for Laboratory Animal Experimentation. On the 1324 eligible studies, 11 were included. All reported advantages in using nanoparticles for the treatment of periodontitis, highlighted by a reduction in bone loss. Agents modulating inflammation seem to be more relevant than antibiotics, in terms of efficiency and risk of antibiotic resistance. In addition, poly(lactic-co-glycolic acid) or drugs used as their own carrier appear to be the most interesting nanoparticles in terms of biocompatibility. Risk of bias assessment highlighted many criteria scored as unclear. There are encouraging preclinical data of using nanoparticles as a contribution to the treatment of periodontitis.

Dual-Functionalized Apatite Nanocomposites with Enhanced Cytocompatibility and Osteogenesis for Periodontal Bone Regeneration

The development of biomimetic bone graft materials for periodontal tissue engineering is a field of topical interest. In this study, we designed a dual-functionalized apatite nanocomposite, which could integrate multiple molecular cues for manipulating the fate of periodontal ligament stem cells (PDLSCs). Briefly, inspired by mussels, a biomimetic nanohydroxyapatite was fabricated using a polydopamine structure as a template (named as tHA) and then surface-modified with bone-forming peptide-1 (BFP-1) and vascular endothelial growth factor-mimicking peptide (QK) via a single step of catechol chemistry. Our study showed that the biofunctions of tethered peptides were not compromised on the surface of apatite nanoparticles. Because of the synergistic effect of BFP-1 and QK peptides, the dual-functionalized apatite nanocomposite showed improved cytocompatibility compared to controls. Moreover, it can boost the proliferation and osteogenic differentiation of PDLSCs, indicating excellent bioactivity of tHA-BFP/QK nanoparticles on cell fate decision. More importantly, animal experiments showed that dual-functionalized apatite nanocomposites could dramatically promote the regeneration of periodontal bone. It is concluded that our work provides an instructive insight into the design of biomimetic apatite nanocomposites, which holds a great potential for applications in periodontal bone repair.