Optimization of 5' Untranslated Region of Modified mRNA for Use in Cardiac or Hepatic Ischemic Injury.

Modified mRNA (modRNA) is a gene-delivery platform for transiently introducing a single gene or several genes of interest to different cell types and tissues. modRNA is considered to be a safe vector for gene transfer, as it negligibly activates the innate immune system and does not compromise the genome integrity. The use of modRNA in basic and translational science is rising, due to the clinical potential of modRNA. We are currently using modRNA to induce cardiac regeneration post-ischemic injury. Major obstacles in using modRNA for cardiac ischemic disease include the need for the direct and single administration of modRNA to the heart and the inefficient translation of modRNA due to its short half-life. Modulation of the 5' untranslated region (5' UTR) to enhance translation efficiency in ischemic cardiac disease has great value, as it can reduce the amount of modRNA needed per delivery and will achieve higher and longer protein production post-single delivery. Here, we identified that 5' UTR, from the fatty acid metabolism gene carboxylesterase 1D (Ces1d), enhanced the translation of firefly luciferase (Luc) modRNA by 2-fold in the heart post-myocardial infarction (MI). Moreover, we identified, in the Ces1d, a specific RNA element (element D) that is responsible for the improvement of modRNA translation and leads to a 2.5-fold translation increment over Luc modRNA carrying artificial 5' UTR, post-MI. Importantly, we were able to show that 5' UTR Ces1d also enhances modRNA translation in the liver, but not in the kidney, post-ischemic injury, indicating that Ces1d 5' UTR and element D may play a wider role in translation of protein under an ischemic condition.

Apnoea in relation to neonatal temporal lobe haemorrhage.

BACKGROUND: Six term newborns presented with apnoea and temporal lobe haemorrhage. AIM: In this observational study, we described involvement of the limbic system in apnoeic term newborns with temporal lobe injury. METHODS: Six term newborns presented to the neonatal care unit with apnoea within the first 2 days of life. Ultrasound (US) and MRI of the brain were obtained in the first week of life. RESULTS: Apnoea was related to temporal lobe haemorrhage in all. During apnoeic periods four had focal epileptic activity on EEG. All lesions were detected first with US. On MRI, haemorrhages were located in the parenchyma, the subdural and/or subarachnoid space. Three haemorrhages were surrounded by infarction in the temporal lobe. In three infants hippocampus and mesial temporal cortex were affected. In two basal temporal cortex only was involved. Vascular anomalies were excluded by MRA, serial MRI or serial US with Doppler imaging. CONCLUSION: Term infants with seizure associated apnoea may present with haemorrhage and/or infarction to hippocampus, mesial and basal temporal cortex. This study supports the existence and possible disruption of descending influences from the temporal cortex and/or amygdala on brainstem breathing centres in the term newborn.