Purpose Leber hereditary optic neuropathy (LHON) is a disorder characterized by severe and rapidly progressive visual loss when caused by a mutation in the mitochondrial gene encoding NADH:ubiquinone oxidoreductase subunit 4 (ND4). We have initiated a gene therapy trial to determine the safety and tolerability of escalated doses of an adeno-associated virus vector (AAV) expressing a normal ND4 complementary DNA in patients with a G to A mutation at nucleotide 11778 of the mitochondrial genome. Design In this prospective open-label trial (NCT02161380), the study drug (self-complementary AAV [scAAV]2(Y444,500,730F)-P1ND4v2) was intravitreally injected unilaterally into the eyes of 5 blind participants with G11778A LHON. Four participants with visual loss for more than 12 months were treated. The fifth participant had visual loss for less than 12 months. The first 3 participants were treated at the low dose of vector (5 × 109 vg), and the fourth participant was treated at the medium dose (2.46 × 1010 vg). The fifth participant with visual loss for less than 12 months received the low dose. Treated participants were followed for 90 to 180 days and underwent ocular and systemic safety assessments along with visual structure and function examinations. Participants Five legally blind patients with G11778A LHON. Main Outcome Measures Loss of visual acuity. Results Visual acuity as measured by the Early Treatment Diabetic Retinopathy Study (ETDRS) eye chart remained unchanged from baseline to 3 months in the first 3 participants. For 2 participants with 90-day follow-up, acuity increased from hand movements to 7 letters in 1 and by 15 letters in 1, representing an improvement equivalent to 3 lines. No one lost vision, and no serious adverse events were observed. Minor adverse events included a transient increase of intraocular pressure (IOP), exposure keratitis, subconjunctival hemorrhage, a sore throat, and a transient increase in neutralizing antibodies (NAbs) against AAV2 in 1 participant. All blood samples were negative for vector DNA. Conclusions No serious safety problems were observed in the first 5 participants enrolled in this phase I trial of virus-based gene transfer in this mitochondrial disorder. Additional study follow-up of these and additional participants planned for the next 4 years is needed to confirm these preliminary observations.

OBJECTIVE To determine the effects of escalating doses of AAV2(Y444,500,703F)-P1ND4v2 in patients with LHON caused by the G11778A mutation in mitochondrial DNA. DESIGN Prospective open-label, unilateral single-dose, intravitreal injection of AAV2(Y444,500,703F)-P1ND4v2 per subject in a phase I clinical trial study initiated in 2014. PARTICIPANTS Fourteen patients with visual loss and mutated G11778A mitochondrial DNA. INTERVENTION Intravitreal injection with the gene therapy vector AAV2(Y444,500,703F)-P1ND4v2 into one eye. Six participants with chronic bilateral visual loss greater than 12 months (Group I), 6 participants with bilateral visual loss less than 12 months (Group II) and 2 participants with unilateral visual loss (Group III) were treated. Nine patients had at least 12 months of follow-up. Clinical testing included ETDRS visual acuity, visual fields, OCT, PERG and neuro-ophthalmic examinations. GEE methods were used for longitudinal analyses. PRIMARY OUTCOME MEASURE Loss of visual acuity. RESULTS For Groups I and II, month 12 average acuity improvements with treatment relative to baseline were 0.24 logMAR. Fellow eyes had a 0.09 logMAR improvement. A post-hoc comparison found that at month 12, the difference between study eye minus fellow eye improvement in Group II patients of 0.53 logMAR was greater than that observed in our prior acute natural history patients of 0.21 logMAR (p=0.053). At month 18, the difference between study eye minus fellow eye improvement in our acute Group II gene therapy patients of 0.96 was greater than that observed in our prior acute natural history patients (0.17 logMAR) p<0.001. Two patients developed asymptomatic uveitis that resolved without treatment. OCT of treated eyes had an average temporal RNFL thickness of 54 μm prior to injection and 55 μm at month 12. For fellow eyes prior to injection it was 56 μm dropping to 50 μm at month 12, p = 0.013. GEE suggested that PERG amplitudes worsened more in treated eyes than in fellow eyes by about 0.05 uV (p exchangeable = 0.009). No difference between eyes in outcomes of other visual function measures was evident. CONCLUSIONS Allotopic gene therapy for LHON at low and medium doses appears safe and does not damage the temporal RNFL opening the door for testing of the high dose next.

An increase in cardiac workload, ultimately resulting in hypertrophy, generates oxidative stress and therefore requires the activation of both survival and growth signal pathways. Here, we wanted to characterize the regulators, targets and mechanistic roles of miR-142, a microRNA (miRNA) negatively regulated during hypertrophy. We show that both miRNA-142-3p and -5p are repressed by serum-derived growth factors in cultured cardiac myocytes, in models of cardiac hypertrophy in vivo and in human cardiomyopathic hearts. Levels of miR-142 are inversely related to levels of acetyltransferase p300 and MAPK activity. When present, miR-142 inhibits both survival and growth pathways by directly targeting nodal regulators p300 and gp130. MiR-142 also potently represses multiple components of the NF-κB pathway, preventing cytokine-mediated NO production and blocks translation of α-actinin. Forced expression of miR-142 during hypertrophic growth induced extensive apoptosis and cardiac dysfunction; conversely, loss of miR-142 fully rescued cardiac function in a murine heart failure model. Downregulation of miR-142 is required to enable cytokine-mediated survival signalling during cardiac growth in response to haemodynamic stress and is a critical element of adaptive hypertrophy.

No abstract