| Zusammenfassung |
Three million people in the UK have a rare disease, a topic the NHS is now urgently addressing, with personalised medicines such as gene therapy envisaged as eventual gold standards. Our own long-term vision is for effective, safe, and long-lasting transformative medical treatments for people with rare early onset lower urinary tract (REOLUT) diseases. These have devastating life-long effects on the health of affected people, not only causing urinary incontinence but also leading to severe urine infections and even life-threatening kidney failure. To reach our goals we must understand the, sometimes genetic, aetiology of these disorders and the detailed biology of how the LUT phenotype arises. In this project we will illuminate the autonomic neural and bladder pathobiology underlying the devastating early onset REOLUT disease called the urofacial, or Ochoa, syndrome (UFS). The key feature of this autosomal recessive disorder is the inability to fully empty the bladder, a functional voiding defect that occurs in the absence of anatomical bladder outflow obstruction (BOO). In parallel, we will study the efficacy and safety of gene therapy treatments to correct aberrant bladder physiology in mutant mouse models of the human genetic disease. As in the human disease, our mouse models carry biallelic variants of either HPSE2, coding for heparanase-2, or LRIG2, coding for leucine rich repeats and immunoglobulin like domains-2. A key biological and therapeutic focus in UFS is the pelvic ganglion (PG), the autonomic relay station that innervates the bladder. Our published studies strongly suggest that bladder dysfunction in UFS is caused by abnormal maturation and subsequent dysfunction of bladder nerves emanating from the PG. Coincidentally, the PG has recently been the focus of exciting studies that demonstrate it has a unique molecular signature compared with either cranial parasympathetic or typical thoracolumbar sympathetic ganglia. Our therapy experiments in this project will build on our recent experimental breakthrough demonstrating the feasibility of neonatal adenovirus vector (AAV)-mediated human HPSE2 gene transfer into, and expression within, the PG. This strategy ameliorated neurogenic bladder defects in juvenile Hpse2 mutant mice as assessed by ex-vivo myography studies. Here we will use the same approach and determine whether bladder nerve pattering is rescued, as assessed by whole-mount immunostaining, and critically whether functionality is restored in the living organism, as assessed by in-vivo cystography. In parallel, we will use single cell RNA sequencing to test the hypothesis that the Hpse2 mutant PG has lost its unique molecular identity, and that this can be restored by neonatal gene therapy. In the second part of the project, we will undertake gene replacement therapy in Lrig2 mutant mice, and we will compare gene expression in Lrig2 and Hpse2 mutant ganglia to define shared molecular pathways in UFS. To provide further translational steps toward human therapy, we will modify our neonatal therapy protocol to give gene therapy later after birth to determine whether correction is possible in mice with more established disease. We will also undertake analyses of a wide range of organs to clarify the safety of our therapeutic approach. Our study will be a paradigm for understanding and treating the expanding list of REOLUT diseases that have defined monogenic causes. |
