Safety Evaluation Of Intracerebral Injection Of Lentiviral ABCD1 For X-ALD Gene Therapy

Objective: X-linked adrenoleukodystrophy(X-ALD)is a sever neurological disease caused by the ABCD1 gene mutation in the X chromosome.Gene therapy is a promising strategy for persistent treatment of the disease.As a tool of transfection,lentiviral vector has a high transfection efficiency for neurons.Therefore,we proposed to inject the LV.hABCD1 vector directly into the brain of mice for safety and effectiveness evaluation of the intracerebral gene therapy.Methods: in this study,we first designed a lentivirus vector carrying the human ABCD1 gene,and then conducted an in vitro experiment to assessed safety in cells.Vector copy number and the expression of ABCD1 protein were detected in cells.Then we did in vivo experiments on mouse models,we did the unilateral injection and multi-site bilateral injection respectively.Next we assessed the distribution of lentiviral vector in injected mice brain through the vector copy number and expression of ABCD1 protein.Results and conclusion: in the cell-level experiment,the cells of the patients transfected with lentiviral vectors got the expression of ABCD1 protein,without any cytotoxic and abnormality.The cellular morphology and the growth state were no different from that of the non-transfected cells.And in mouse model experiments,we found that the lentiviral vector carrying human ABCD1 can be expressed in the whole area of the brain in treated mice.The mice have normal behavior and activity.After sacrificed,we found no neuroinflammation and abnormalities in the brain of mice.In addition,we found that lentivirus can migrate significantly to the contralateral brain through nerve cells,but no inflammatory response or other abnormalities occur.Furthermore,the results showed that the lentiviral vectors migrated to the contralateral brain area through neural cell transport and observed the ABCD1 overexpression without inflammatory response.Compared with mice that were not intracerebral injected,the overexpression of ABCD1 in the brain did not affect the life activity and behavior of the mice,and their body weight were also normal.These results support the rationale for the safety and feasibility of intracerebral lentiviral gene therapy to treat neurological diseases,and provide a potential and promising therapeutic strategy for treating X-ALD.