Preclinical Evaluation of Long-Term Neuroprotective Effects of BDNF-Engineered Mesenchymal Stromal Cells as Intravitreal Therapy for Chronic Retinal Degeneration in Rd6 Mutant Mice.

Renata Lejkowska,Miłosz Kawa,Anna Machalińska,Dorota Rogińska,Bogusław Machaliński,Ewa Pius-Sadowska,Karolina Łuczkowska

doi:10.3390/ijms20030777

Renata Lejkowska, Miłosz Kawa + Show 5 more

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https://doi.org/10.3390/ijms20030777

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Abstract

This study aimed to investigate whether the transplantation of genetically engineered bone marrow-derived mesenchymal stromal cells (MSCs) to overexpress brain-derived neurotrophic factor (BDNF) could rescue the chronic degenerative process of slow retinal degeneration in the rd6 (retinal degeneration 6) mouse model and sought to identify the potential underlying mechanisms. Rd6 mice were subjected to the intravitreal injection of lentivirally modified MSC-BDNF or unmodified MSC or saline. In vivo morphology, electrophysiological retinal function (ERG), and the expression of apoptosis-related genes, as well as BDNF and its receptor (TrkB), were assessed in retinas collected at 28 days and three months after transplantation. We observed that cells survived for at least three months after transplantation. MSC-BDNF preferentially integrated into the outer retinal layers and considerably rescued damaged retinal cells, as evaluated by ERG and immunofluorescence staining. Additionally, compared with controls, the therapy with MSC-BDNF was associated with the induction of molecular changes related to anti-apoptotic signaling. In conclusion, BDNF overexpression observed in retinas after MSC-BDNF treatment could enhance the neuroprotective properties of transplanted autologous MSCs alone in the chronically degenerated retina. This research provides evidence for the long-term efficacy of genetically-modified MSC and may represent a strategy for treating various forms of degenerative retinopathies in the future.

Highlights

Inherited or acquired retinal degeneration involving the retinal pigment epithelium (RPE) and photoreceptors is a major cause of loss of vision leading to complete blindness throughout the world
enzyme-linked immunosorbent assay (ELISA) results revealed a significant increase in the brain-derived neurotrophic factor (BDNF) concentration in medium collected from the BDNF–positive mesenchymal stromal cells (MSCs) culture compared to the uninfected MSC in the same conditions (Figure 1E)
The expression of BDNF protein remained at a constant expression level (Figure 3B). These results indicate that genetically modified MSC used to express exogenous BDNF, which were transplanted into slowly degenerating retinas of rd6 mice, may produce the neurotrophic growth factor—BDNF—locally at the protein level for at least three months after their transplantation

Summary

Introduction

Inherited or acquired retinal degeneration involving the retinal pigment epithelium (RPE) and photoreceptors is a major cause of loss of vision leading to complete blindness throughout the world. Retinal degeneration involves complex processes and the pathophysiological mechanisms are not fully known. Numerous strategies have been performed to stop the degeneration process in the retina and to replace damaged cells, but their therapeutic effects were very limited [2]. This inefficacy is because the genetic and phenotypic heterogeneity of the retinal degeneration process makes the development of a single therapeutic approach a very challenging process [3]. Several factors that contribute to retinal neurodegeneration have been partially identified, including augmented oxidative stress, and dynamic metabolic changes in retinal cells owing to the activation of inflammatory responses and decreased availability of vital trophic factors

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