Apoptosis in the gut triggers an expansion in the Enterobacteriaceae family of bacteria, causing both prolonged tissue injury and delayed repair. However, the mechanisms linking the Enterobacteriaceae bloom and subsequent deleterious tissue response are relatively unknown. Here, we establish purines as a major component of the apoptotic secretome that are consumed by bacteria. Explicitly, we identify hypoxanthine as a critical metabolite that is taken up and metabolised by both pathogenic and commensal species within the Enterobacteriaceae family. Epithelial cells release hypoxanthine into the extracellular space during early stages of apoptosis via the upregulation of equilibrative nucleoside transporters 1/2 (ENT1/2). Critically, beyond simply linking host and microbe, we delineate a connection between the release of hypoxanthine from the dying cell and the ability of the host to repair damaged epithelial tissue. Hypoxanthine is a potent promoter of epithelial cell repair in both gut and skin across the phylogenetic tree including humans, mice, zebrafish, and fruit flies and promotes similar ATP production and cellular proliferation in eukaryotic and microbial recipients. Thus, the preferential utilisation of hypoxanthine by the Enterobacteriaceae directly competes with the host for a core reparative signal.
Sam Benson, Priscilla Chin, Sebastian Rogatti et al.· bioRxiv· 0 citations
Heterozygous de novo missense mutations in the EEF1A2 gene encoding translation elongation factor eEF1A2 result in neurodevelopmental disorders, typically characterised by early onset epilepsy and intellectual disability (ID). The E122K mutation is the most commonly reported missense mutation and is amongst the more severe in terms of epilepsy and ID. Here we made use of a recently developed mouse model which recapitulates the E122K mutation to examine how mutations in EEF1A2 might disrupt neuronal gene expression. Primary neurons from mutant mice and transfected HEK293T cells were used to examine effects on global protein synthesis. In contrast to previous reports, we were unable to detect a change in global protein synthesis using either of two different assay systems. TRAP-seq and mass spectrometry were then employed to study the effects of the mutation on the translatome and proteome respectively. These analyses revealed perturbation of expression of a subset of genes, with a slight skew towards downregulation, particularly for longer transcripts. Further analysis indicated a down regulation of proteins involved in synaptic function in both the translatomic and proteomic datasets.
Cavan Bennett Ness, Manuela Rizzi, Heather Love et al.· bioRxiv· 0 citations
