Gene Editing Research
There are currently several teams around the world working on gene editing techniques for X-Linked Hyper IgM Syndrome. As these research teams publish papers and show results we will keep you updated on their results. If you would like to participate in a study we can direct you to the right teams working on your form of HIGM. Please email [email protected]
The last published article has come out from Seattle with the publishing of a paper in the Blood Journal by the Center for Immunity and Immunotherapies, Seattle Children’s Research Institute. The article is called Targeted gene editing restores regulated CD40L expression and function in X-HIGM T cells. This is a very early stage gene editing technique that has shown promise for a potential therapy for X-Linked Hyper IgM Syndrome (known as CD40L Deficiency). For a detailed description and breakdown of the finding of the paper click here:
Nicholas Hubbard, David Hagin, Karen Sommer, Yumei Song, Iram Khan, Courtnee Clough, Hans D. Ochs, David J. Rawlings, Andrew M. Scharenberg, and Troy R. Torgerson,
Loss of CD40L expression or function results in X-Linked Hyper-IgM Syndrome (X-HIGM), characterized by recurrent infections due to impaired immunoglobulin class-switching and somatic hypermutation. Previous attempts using retroviral gene transfer to correct murine CD40L expression restored immune function; however, treated mice developed lymphoproliferative disease, likely due to viral-promoter dependent constitutive CD40L expression. These observations highlight the importance of preserving endogenous gene regulation in order to safely correct this disorder. Here we report efficient, on-target, homology directed repair (HDR) editing of the CD40LG locus in primary human T cells using a combination of a TALEN-induced double-strand break and a donor template delivered by recombinant Adeno-Associated Virus (rAAV). HDR mediated insertion of a coding sequence (GFP or CD40L) upstream of the translation start site within Exon 1 allowed transgene expression to be regulated by endogenous CD40LG promoter/enhancer elements. Additionally, inclusion of the CD40LG 3′-untranslated region (3′-UTR) in the transgene preserved post-transcriptional regulation. Expression kinetics of the transgene paralleled that of endogenous CD40L in unedited T cells, both at rest and in response to T cell stimulation. The use of this method to edit X-HIGM patient T cells restored normal expression of CD40L and CD40-muIg binding, and rescued IgG class switching of naïve B-cells in vitro. These results demonstrate the feasibility of engineered nuclease-directed gene repair to restore endogenously regulated CD40L, and the potential for its use in T cell therapy for X-HIGM syndrome. Submitted November 23, 2015.
Another team working on gene editing is a lab in UCLA working on a paper called: “Targeted Gene Therapy in the Treatment of X-Linked Hyper-IgM Syndrome.” by Caroline Y. Kuo, MD, Alok Joglekar, PhD, & Donald B. Kohn, MD. They presented their abstract at the 2014 CIS Annual Meeting:
X-linked hyper-IgM syndrome results in absent IgG, IgA, IgE and normal/elevated IgM due to defects in the CD40 ligand gene. HSCT is the only curative modality, but it carries significant risks, suggesting the need for improved methods of treatment. TALENs or CRISPRs, combined with the effective delivery of a homologous donor sequence containing normal CD40L DNA, will allow for targeted integration and provide physiologic expression of the endogenous CD40L gene to provide long-term immune reconstitution. TALENs targeting the 5′ UTR of the CD40L gene lead to allelic disruption of up to 31%at the target locus inK562 cells. In order to evaluate the capacity for targeted integration of a cassette at the cut site, cells were electroporated with the TALEN pair and a donor molecule with a promoterless GFP reporter gene flanked by homology arms. Expression of the GFP reporter was evaluated in Jurkat cells, with up to 10 % detected by flow cytometry and increasing to 22 % upon PHA activation. In addition, CRISPRs targeting a patient-specific mutation in intron 3 achieved >50 % gene disruption in K562 cells. Co-electroporation with a donor modified to contain a unique restriction enzyme site demonstrated site-specific gene integration. Site-specific modification at CD40L is achievable and physiologic expression of the endogenous CD40L gene could provide a viable therapy for XHIM.
If you are interested in participating in this or another study we can direct you to the right teams working on your form of HIGM. Please email [email protected]