Jinadasa, T. | bioRxiv Science

bioRxiv2026

High-throughput discovery of arginine-depleted peptides enables effective antisense delivery for Duchenne muscular dystrophy

Phosphorodiamidate morpholino oligomers (PMOs) are approved exon-skipping antisense therapeutics for Duchenne muscular dystrophy (DMD), but their clinical utility is limited by poor uptake in muscle tissue, necessitating frequent high-dose administration. Cell-penetrating peptides (CPPs) can enhance intracellular delivery of PMOs, yet conventional arginine-rich CPPs often cause dose-limiting toxicity, including renal damage, which hinders their clinical translation. To address this challenge, we developed a high-throughput, charge-based chromatographic enrichment platform capable of screening over 15,000 synthetic peptides, including sequences with noncanonical (abiotic) amino acids. This approach enabled de novo discovery of arginine-depleted CPPs with improved delivery profiles. Four lead candidates demonstrated efficient nuclear PMO delivery with ~10-fold lower in vitro toxicity compared to standard CPPs such as penetratin. The top-performing peptide, CXP1, showed robust splice-switching activity and favorable tolerability in both cellular and animal models. In dystrophic mdx mice, CXP1-PMO conjugates achieved greater exon skipping compared to PMOs conjugated to R6G at equivalent doses. Tissue levels of CXP1-PMO correlated with exon-skipping efficacy, establishing a clear pharmacokinetic-pharmacodynamic relationship. These findings highlight a mechanistically novel and translationally relevant discovery strategy, demonstrating the potential of high-throughput platforms to generate more effective CPP-based delivery vehicles for antisense therapeutics in DMD and related neuromuscular disorders. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=44 SRC="FIGDIR/small/730741v1_ufig1.gif" ALT="Figure 1"> View larger version (13K): org.highwire.dtl.DTLVardef@84b7f2org.highwire.dtl.DTLVardef@1487850org.highwire.dtl.DTLVardef@d2e263org.highwire.dtl.DTLVardef@10ce371_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2019

Increased expression of schizophrenia-associated gene C4 leads to hypoconnectivity of prefrontal cortex and reduced social interaction

Schizophrenia is a severe mental disorder with an unclear pathophysiology. Increased expression of the immune gene C4 has been linked to a greater risk of developing schizophrenia; however, it is unknown whether C4 plays a causative role in this brain disorder. Using confocal imaging and whole-cell electrophysiology, we demonstrate that overexpression of C4 in mouse prefrontal cortex neurons leads to perturbations in dendritic spine development and hypoconnectivity, which mirror neuropathologies found in schizophrenia. We find evidence that microglia-neuron interactions and microglia-mediated synaptic engulfment are enhanced with increased expression of C4. We also show that C4-dependent circuit dysfunction in the frontal cortex leads to decreased social interactions in juvenile mice. These results demonstrate that increased expression of the schizophrenia-associated gene C4 causes aberrant circuit wiring in the developing prefrontal cortex and leads to deficits in early social behavior, suggesting that altered C4 expression contributes directly to schizophrenia pathogenesis.

neuroscience↗