Biology subjects

Huq, S.

Publications and source records attributed to Huq, S..

2 recordsLinked to original sources

bioRxiv2026

CRISPR-mediated Correction of Oncogenic AS-NMD in Splicing Factor Mutant Cancer

Alternative splicing coupled to nonsense-mediated mRNA decay (AS-NMD) evolved as a master regulator of gene expression. Dysregulated AS-NMD has been identified as the root of many human maladies, from developmental defects to deadly cancer. Poison exons (PEs) are highly conserved alternative exons that contain a premature termination codon and elicit AS-NMD when included in a transcript. Cancer cells often exploit the inclusion of PEs to downregulate tumor suppressors or the exclusion of PEs to upregulate oncoproteins. Therefore, PEs have drawn significant attention as a novel therapeutic avenue for cancer and other diseases. Here, we examine a therapeutic proof-of-concept for manipulating PE-mediated oncogenic AS-NMD using a CRISPR-based approach. Using paired guide RNA, we successfully deleted a PE of a tumor suppressor (EZH2) from the genome of SRSF2-mutated leukemia. This editing resulted in EZH2 mRNAs without a PE, escaped AS-NMD, and restored the protein expression. This subsequently reinstated H3K27 histone methylation and rescued defective chromatin regulation associated with impaired hematopoietic stem cell differentiation. Finally, we showed the preferential advantages of CRISPR over the antisense technology we recently developed targeting the PE of EZH2. Therefore, the CRISPR strategy shows compelling evidence as a therapeutic approach targeting PE in cancer and other human diseases.

cancer biology↗

bioRxiv2025

Dissipation of lysosome pH impairs formation and collapses existing LPS-induced lysosome tubules in macrophages

While lysosomes are typically globular in morphology, lipopolysaccharide-activated macrophages reorganize lysosomes into an expanded tubular network. Here, we sought to determine if the V-ATPase and the lysosomal pH contribute to LPS-mediated lysosome tubulation in macrophages. We found that inhibition of the V-ATPase prevented lysosome tubulation and collapsed preformed tubules. However, the V-ATPase also controls mTORC1 activity, which itself is needed for tubulation. To distinguish between lysosomal pH and mTORC1, we turned to NH4Cl, which alkalinized lysosomal pH but did not interfere with mTORC1; yet NH4Cl blocked tubulation showing that an acidic lysosomal pH is needed for lysosome remodelling. Moreover, clamping the pH to either acidic or alkaline pH caused tubules to collapse, indicating that the pH gradient promotes tubulation, rather than a specific pH. These effects were not due to altered microtubule organization or impaired lysosome motility, suggesting that motors remained associated with lysosomes. On the other hand, while LPS did not alter the average pH of spherical or tubular lysosomes, growing tubules displayed a more acidic peripheral end relative to the pericentral end. Based on this observation, we propose that a localized pH gradient along the tubule may enable tubulation by modulating factors that catalyse tubule growth.

cell biology↗