Cholesteryl hemiazelate causes lysosome dysfunction impacting vascular smooth muscle cell homeostasis

In atherosclerotic lesions, vascular smooth muscle cells (VSMCs) represent half of the foam cell population, which is characterized by an aberrant accumulation of undigested lipids within lysosomes. Loss of lysosome function impacts VSMC homeostasis and disease progression. Understanding the molecular mechanisms underlying lysosome dysfunction in these cells is, therefore, crucial. We identify cholesteryl hemiazelate (ChA), a stable oxidation end-product of cholesteryl-polyunsaturated fatty acid esters, as an inducer of lysosome malfunction in VSMCs. ChA-treated VSMCs acquire a foam-cell-like phenotype, characterized by enlarged lysosomes full of ChA and neutral lipids. The lysosomes are perinuclear and exhibit degradative capacity and cargo exit defects. Lysosome luminal pH is also altered. Even though the transcriptional response machinery and autophagy are not activated by ChA, the addition of recombinant lysosomal acid lipase (LAL) is able to rescue lysosome dysfunction. ChA significantly affects VSMC proliferation and migration, impacting atherosclerosis. In summary, this work shows that ChA is sufficient to induce lysosomal dysfunction in VSMCs, that, in ChA-treated VSMCs, neither lysosome biogenesis nor autophagy are triggered, and, finally, that recombinant LAL can be a therapeutic approach for lysosomal dysfunction

A selective p53 activator and anticancer agent to improve colorectal cancer therapy

Impairment of the p53 pathway is a critical event in cancer. Therefore, reestablishing p53 activity has become one of the most appealing anticancer therapeutic strategies. Here, we disclose the p53-activating anticancer drug (3S)-6,7-bis(hydroxymethyl)-5-methyl-3-phenyl-1H,3H-pyrrolo[1,2-c]thiazole (MANIO). MANIO demonstrates a notable selectivity to the p53 pathway, activating wild-type (WT)p53 and restoring WT-like function to mutant (mut)p53 in human cancer cells. MANIO directly binds to the WT/mutp53 DNA-binding domain, enhancing the protein thermal stability, DNA-binding ability, and transcriptional activity. The high efficacy of MANIO as an anticancer agent toward cancers harboring WT/mutp53 is further demonstrated in patient-derived cells and xenograft mouse models of colorectal cancer (CRC), with no signs of undesirable side effects. MANIO synergizes with conventional chemotherapeutic drugs, and in vitro and in vivo studies predict its adequate drug-likeness and pharmacokinetic properties for a clinical candidate. As a single agent or in combination, MANIO will advance anticancer-targeted therapy, particularly benefiting CRC patients harboring distinct p53 status.We thank PT national funds (FCT/MCTES , Fundação para a Ciência e a Tecnologia , and Ministério da Ciência, Tecnologia e Ensino Superior ) through grants UIDB/50006/2020 , UID/BIO/04469/2019 , UIDB/04539/2020 , and UIDP/04539/2020 ( CIBB ); BioTecNorte operation ( NORTE-01-0145-FEDER-000004 ) and Porto Neurosciences and Neurologic Disease Research Initiative at I3S ( Norte-01-0145-FEDER-000008 ) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte ; Masaryk University ( Project MUNI/A/1127/2019 ) and Ministry of Education, Youth and Sports of the Czech Republic (project nos. LQ1605 and LM2018125 ); FCT financial support through the fellowships SFRH/BD/119144/2016 (H.R.) and SFRH/BD/117949/2016 (L.R.); Fondazione AIRC ( IG#18985 , A.I.); and the Programa Operacional Potencial Humano (POCH), specifically the BiotechHealth Programme (Doctoral Programme on Cellular and Molecular Biotechnology Applied to Health Sciences , PD/00016/2012 ). We thank Dario Rizzotto for assistance in preparing the libraries for RNA sequencing. Funding: This work was supported by PT National Funds (FCT/MCTES, Fundação para a Ciência e Tecnologia , and Ministério da Ciência, Tecnologia e Ensino Superior ) via the projects UIDB/50006/2020 ( LAQV/REQUIMTE ), UIDB/00313/2020 , and UIDP/00313/2020 , co-funded by COMPETE2020-UE

Divergent biosynthesis yields a cytotoxic aminomalonate-containing precolibactin

Colibactin represents an as-yet uncharacterized genotoxic secondary metabolite produced by human gut bacteria. Here we report the biosynthetic discovery of two new precolibactin molecules from Escherichia coli, including precolibactin-886 that uniquely incorporates the highly sought genotoxicity-associated aminomalonate building block in its unprecedented macrocyclic structure. This work provides new insights into the biosynthetic logic and mode of action of this colorectal cancer-linked microbial chemical