Dental Pulp Cells Conditioning Through Poly(I:C) Activation of Toll-Like Receptor 3 (TLR3) for Amplification of Trophic Factors

INTRODUCTION

Regeneration of the pulp-dentin complex hinges on functionally diverse growth factors, cytokines, chemokines, signaling molecules, and other secreted factors collectively referred to as trophic factors. Delivery of exogenous factors and induced release of endogenous dentin-bound factors by conditioning agents have been explored towards these goals. The aim of this study was to investigate a promising regeneration strategy based on the conditioning of dental pulp cells (DPCs) with polyinosinic-polycytidylic acid [poly(I:C)] for amplification of endogenous trophic factors.

METHODS

DPCs were isolated from human dental pulps, propagated in culture, and treated with an optimized dose of poly(I:C). MTT assay and metabolite analysis were conducted to monitor the cytotoxicity of poly(I:C). ELISA and qPCR assays were performed to quantify induction of trophic factors in response to DPC conditioning. Statistical significance was P < .05.

RESULTS

Analysis of 32 trophic factors involved in Wnt signaling, cell migration and chemotaxis, cell proliferation and differentiation, extracellular matrix (ECM) remodeling and angiogenesis, and immunoregulation revealed that DPCs abundantly express many trophic factors including AMF, BDNF, BMP2, FGF1, FGF2, FGF5, HGF, MCP1, NGF, SDF1, TGFβ1, TIMP1, TIMP2, TIMP3, and VEGF-A, many of which were further induced by DPC conditioning; induction, which was significant for BDNF, EGF, HGF, LIF, MCP1, SDF1, IL6, IL11, MMP9 and TIMP1. Both DPCs proliferation and lactate production (P < .05) were inhibited by 8 μg/ml poly(I:C) relative to the control.

CONCLUSIONS

In vitro DPC conditioning through poly(I:C) activation of TLR3 led to amplification of trophic factors involved in tissue repair. The strategy offers promise for endodontic regeneration and tooth repair and warrants further investigation.

A Review of Last Decade Developments on Epiretinal Membrane Pathogenesis

Epiretinal membrane (ERM) is a pathologic tissue that develops at the vitreoretinal interface. ERM is responsible for pathological changes of vision with varying degrees of clinical significance. It is either idiopathic or secondary to a wide variety of diseases such as proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). A great variation in the prevalence of idiopathic ERM among different ethnic groups proposed that genetic and lifestyle factors may play a role in ERM occurrence. Histopathological studies demonstrate that various cell types including retinal pigment epithelium (RPE) cells, fibrocytes, fibrous astrocytes, myofibroblast-like cells, glial cells, endothelial cells (ECs) and macrophages, as well as trophic and transcription factors, including transforming growth factor (TGF), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) etc., are directly or indirectly involved in the pathogenesis of idiopathic or secondary ERMs. These processes are driven (on the last count) by more than 50 genes, such as Tumor Necrosis Factor (TNF), CCL2 (chemokine (C-C motif) ligand )), Metastasis Associated Lung Adenocarcinoma Transcript 1 )MALAT1(, transforming growth factor (TGF)-β1, TGF-β2, Interleukin-6 (IL-6), IL-10, VEGF and glial fibrillary acidic protein (GFAP), some of which have been studied more intensely than others. The present paper tried to summarize, highlight and cross-correlate the major findings made in the last decade on the function of these genes and their association with different types of cells, genes and gene expression products in the ERM formation.

Disease Modification for Parkinson's Disease: Axonal Regeneration and Trophic Factors

Disease modification and structural neuroprotection have been the holy grail for Parkinson's disease (PD) experimental therapeutics. Theoretically, there are a number of ways to implement such therapeutics, but to date all have failed. This review examines the potential of axonal regeneration and trophic factor delivery for the nigrostriatal system as 2 such approaches that historically have initiated much excitement. However, we conclude this discussion with the following question: has science passed these approaches by? © 2018 International Parkinson and Movement Disorder Society.