The granular dorsolateral prefrontal cortex (dlPFC) is an evolutionary specialization of primates that is centrally involved in cognition. Here, we assessed over 600,000 single-nucleus transcriptomes from adult human, chimpanzee, macaque, and marmoset dlPFC. While most transcriptomically-defined cell subtypes are conserved, we detected several only in some species and substantial species-specific molecular differences across homologous neuronal, glial and non-neural subtypes. The latter are exemplified by human-specific switching between expression of the neuropeptide somatostatin (SST) and tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine production, in certain interneurons, and also by expression of the neuropsychiatric risk gene FOXP2 , which is human-specific in microglia and primate-specific in layer-4 granular neurons. We generated a comprehensive survey of dlPFC cellular repertoire and its shared and divergent features in anthropoid primates.

The limited capacity for the central nervous system (CNS) to repair itself was first described over 100 years ago by Spanish neuroscientist Ramon Y. Cajal. However, the exact mechanisms underlying this failure in neuronal regeneration remain unclear and, as such, no effective therapeutics yet exist. Numerous studies have attempted to elucidate the biochemical and molecular mechanisms that inhibit neuronal repair with increasing evidence suggesting that several inhibitory factors and repulsive guidance cues active during development actually persist into adulthood and may be contributing to the inhibition of repair. For example, in the injured adult CNS, there are various inhibitory factors that impede the outgrowth of neurites from damaged neurons. One of the most potent of these neurite outgrowth inhibitors is the group of proteins known as the myelin-associated inhibitors (MAIs), present mainly on the membranes of oligodendroglia. Several studies have shown that interfering with these proteins can have positive outcomes in CNS injury models by promoting neurite outgrowth and improving functional recovery. As such, the MAIs, their receptors, and downstream effectors are valid drug targets for the treatment of CNS injury. This review will discuss the current literature on MAIs in the context of CNS development, plasticity, and injury. Molecules that interfere with the MAIs and their receptors as potential candidates for the treatment of CNS injury will additionally be introduced in the context of preclinical and clinical trials.

No abstract