A Novel MYCN Variant Associated with Intellectual Disability Regulates Neuronal Development

Distinct Synaptic Vesicle Proteomic Signatures Associated with Pre- and Post-Natal Oxycodone-Exposure

The current opioid crisis, which has ravaged all segments of society, continues to pose a rising public health concern. Importantly, dependency on prescription opioids such as oxycodone (oxy) during and after pregnancy can significantly impact the overall brain development of the exposed offspring, especially at the synapse. A significant knowledge gap that remains is identifying distinct synaptic signatures associated with these exposed offspring. Accordingly, the overall goal of this current study was to identify distinct synaptic vesicle (SV) proteins as signatures for offspring exposed to oxy in utero (IUO) and postnatally (PNO). Using a preclinical animal model that imitates oxycodone exposure in utero (IUO) and postnatally (PNO), we used a quantitative mass spectrometry-based proteomics platform to examine changes in the synaptic vesicle proteome on post-natal day 14 (P14) IUO and PNO offspring. We identified MEGF8, associated with carpenter syndrome, to be downregulated in the IUO offspring while LAMTOR4, associated with the regulator complex involved in lysosomal signaling and trafficking, was found to be upregulated in the PNO groups, respectively. Their respective differential expression was further validated by Western blot. In summary, our current study shows exposure to oxy in utero and postnatally can impact the SV proteome in the exposed offspring and the identification of these distinct SV signatures could further pave the way to further elucidate their downstream mechanisms including developing them as potential therapeutic targets.

Molecular mechanisms underlying nuchal hump formation in dolphin cichlid, Cyrtocara moorii

East African cichlid fishes represent a model to tackle adaptive changes and their connection to rapid speciation and ecological distinction. In comparison to bony craniofacial tissues, adaptive morphogenesis of soft tissues has been rarely addressed, particularly at the molecular level. The nuchal hump in cichlids fishes is one such soft-tissue and exaggerated trait that is hypothesized to play an innovative role in the adaptive radiation of cichlids fishes. It has also evolved in parallel across lakes in East Africa and Central America. Using gene expression profiling, we identified and validated a set of genes involved in nuchal hump formation in the Lake Malawi dolphin cichlid, Cyrtocara moorii. In particular, we found genes differentially expressed in the nuchal hump, which are involved in controlling cell proliferation (btg3, fosl1a and pdgfrb), cell growth (dlk1), craniofacial morphogenesis (dlx5a, mycn and tcf12), as well as regulators of growth-related signals (dpt, pappa and socs2). This is the first study to identify the set of genes associated with nuchal hump formation in cichlids. Given that the hump is a trait that evolved repeatedly in several African and American cichlid lineages, it would be interesting to see if the molecular pathways and genes triggering hump formation follow a common genetic track or if the trait evolved in parallel, with distinct mechanisms, in other cichlid adaptive radiations and even in other teleost fishes.