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Isik, M.

Publications and source records attributed to Isik, M..

2 recordsLinked to original sources

Pathogenic microbiota disrupts the intact structure of cerebral organoids by altering energy metabolism

This study investigated the impact of different bacterial populations on the biomolecular structures of cerebral organoids (COs) at various levels. COs were co-cultured with non-pathogenic (NM) and pathogenic (PM) bacterial populations. PM reduced the number of TUJ1+ neurons and disrupted the intact structure of COs. In addition, PM was found to induce changes in the transcript profile of COs, including a decrease in the activity of the glycolysis pathway and an increase in the pentose phosphate pathway, leading to deterioration in cellular energy metabolism, which is linked to neurodegenerative diseases. Proteomic analysis revealed a unique cluster of proteins in COs. PM exposure upregulated proteins related to neurological diseases, consistent with RNA-seq data. Communication between bacteria and neural cells was demonstrated using 18O-stable isotope labeling (SIL)-based metabolic flux analysis. COs showed higher 18O-enrichment of TCA cycle intermediates when co-cultured with NM and PM, indicating increased oxidative phosphorylation activity upon exposure to bacteria. This study provides a useful platform to monitor metabolic signals and communication between microbiotas and human brain cells. The findings suggest that pathogenic bacteria release metabolites that alter biomolecular structures in brain organoids, potentially contributing to neurodegenerative diseases.

neuroscience↗

ERK signaling licenses SKN-1A/NRF1 for proteasome production and proteasomal stress resistance

The ubiquitin-proteasome system is vital for cell growth and homeostasis, but for most cancers proteasomal inhibition has not been effective as a therapy. Normal and cancer cells adapt to proteasomal stress through an evolutionarily conserved recovery response, in which the transcription factor NRF1 upregulates proteasome subunit genes. Starting with a C. elegans screen to identify regulators of the recovery response, here we show that this response depends upon phosphorylation of NRF1 on a single residue by the growth factor-activated kinase ERK1/2. Inhibition of this phosphorylation impairs NRF1 nuclear localization and proteasome gene activation, sensitizes C. elegans and cancer cells to proteasomal stress, and synergizes with proteasome inhibition to retard human melanoma growth in vivo in a mouse model. The evolutionarily conserved ERK1/2-NRF1 axis couples proteasome production to growth signaling, and represents a promising new strategy for expanding the range and efficacy of proteasomal inhibition therapy in cancer.

cell biology↗