Correction in trans for Fabry disease: expression, secretion and uptake of alpha-galactosidase A in patient-derived cells driven by a high-titer recombinant retroviral vector.

Abstract

Fabry disease is an X-linked metabolic disorder due to a deficiency of a-galactosidase A (a-gal A; EC 3.2

Efficient correction of Fabry mice and patient cells mediated by lentiviral transduction of hematopoietic stem/progenitor cells

“…Note that these therapeutic transgene expression levels are substantially higher with a single recombinant LV infection than we observed previously with four oncoretroviral infections. 11 With lower MOIs, lysate a-gal A activity was lower than normal B cell levels but still above background Fabry patient B cell a-gal A activity even at an estimated MOI of 0.1.…”

“…20 We assessed the efficacy of our marking and therapeutic LVs in immortalized, patient-derived B cells. 11 For these experiments, 0.2 Â 10 6 cells were infected a single time at various estimated MOIs using LV/enGFP and LV/a-gal A. MOIs for the LV/a-gal A construct were estimated by comparing p24 levels with those functional titer outcomes obtained on infected test cells with similar p24 values from the LV/enGFP construct (data not shown).…”

“…[11][12][13][14] A major hurdle to application of this approach in clinical studies for Fabry disease and other LSDs, however, is to accomplish efficient gene transfer into true HSPCs, which can then be transplanted to achieve stable, robust and long-term expression of corrective genes in progeny cells. This is a challenging task for the RVs currently in clinical trials.…”

“…9 Secondly, non-modified hematopoietic stem/progenitor cells (HSPCs) and their progeny do not secrete therapeutic levels of target enzyme, which can be taken up at a distance by affected organs in a process termed 'metabolic cooperativity' or 'cross-correction'. 10,11 Autologous SCT alleviates risks involved with GvHD and will likely be even more effective at systemic correction of LSDs and other disorders if the target cells have been genetically modified to over-produce and secrete the therapeutic enzyme before transplantation.…”

Preselective gene therapy for Fabry disease

“…This is because metabolic cooperativity (or cross-correction) occurs whereby uncorrected ''bystander'' cells take up and use recombinant ␣-galactosidase A (␣-gal A) secreted by engineered cells (1)(2)(3). In this way, small numbers of transduced cells can effect correction of a larger number of nontransduced cells in vivo.…”