Phenotypic Correction of Murine Mucopolysaccharidosis Type II by Engraftment of Ex Vivo Lentiviral Vector-Transduced Hematopoietic Stem and Progenitor Cells.

Mucopolysaccharidosis type II (MPS II, Hunter syndrome) is an X-linked recessive lysosomal disease caused by deficiency of iduronate-2-sulfatase (IDS). The absence of IDS results in the accumulation of the glycosaminoglycans (GAGs) heparan sulfate and dermatan sulfate. Currently, the only approved treatment option for MPS II is enzyme replacement therapy (ERT), Elaprase. However, ERT is demanding for the patient and does not ameliorate neurological manifestations of the disease. Using an IDS-deficient mouse model that phenocopies the human disease, we evaluated hematopoietic stem and progenitor cells (HSPCs) transduced with a lentiviral vector (LVV) carrying a codon-optimized human IDS coding sequence regulated by a ubiquitous MNDU3 promoter (MNDU3-IDS). Mice treated with MNDU3-IDS LVV-transduced cells showed supraphysiological levels of IDS enzyme activity in plasma, peripheral blood mononuclear cells, and in most analyzed tissues. These enzyme levels were sufficient to normalize GAG storage in analyzed tissues. Importantly, IDS levels in the brains of MNDU3-IDS-engrafted animals were restored to 10-20% than that of wild-type mice, sufficient to normalize GAG content and prevent emergence of cognitive deficit as evaluated by neurobehavioral testing. These results demonstrate the potential effectiveness of ex vivo MNDU3-IDS LVV-transduced HSPCs for treatment of MPS II.

Fecal Lipocalin-2 as a Sensitive and Noninvasive Biomarker in the TNBS Crohn's Inflammatory Bowel Disease Model.

Colitis induced by 2,4,6-Trinitrobenzenesulfonic acid (TNBS) has been used as a model for Crohn's disease (CD) of inflammatory bowel disease (IBD). Lipocalin-2 (Lcn-2) is an emerging and clinically relevant biomarker of IBD. We investigated the performance of serum and fecal Lcn-2 in the TNBS model of colitis. Female, 7-week-old, BALB/c mice were administered intrarectally phosphate-buffered saline/water or 30% ethanol (vehicle control groups) for 5 days or TNBS for 5 days followed by a 28-day recovery phase. Serum and fecal levels of Lcn-2 were quantified, and effects on body weight, clinical scores, colon weight and length, gross pathology, and histopathology were investigated. Increased serum Lcn-2 levels correlated only with marked to severe inflammation. A clear differentiation in Lcn-2 fecal levels between TNBS-treated and vehicle-treated control mice was most noticeable on days 2 and 3. There was a strong correlation between body weight change, histopathologic scores of inflammation, and/or fecal Lcn-2 levels on days 2 and 5. Both serum and fecal Lcn-2 levels declined over time as the colonic mucosa recovered. Fecal Lcn-2 was found to be a more sensitive biomarker (vs. serum Lcn-2) and was able to discriminate mild, moderate, and severe colonic inflammation.