Biology subjects

Garippa, R.

Publications and source records attributed to Garippa, R..

3 recordsLinked to original sources

bioRxiv2026

miR-940 suppresses ferroptosis by controlling expression of key regulatory genes

Ferroptosis is a form of regulated cell death that is characterized by iron-dependent lipid peroxidation. This process is regulated by specific metabolites, the lipid composition of the cells, redox-active iron, and antioxidant mechanisms. Although numerous regulators have been identified over the past decade, exploring other mechanisms, particularly from non-coding genomic regions, can build a thorough understanding of the multifaceted regulatory processes underlying ferroptosis. MicroRNAs (miRNAs) play a crucial role in gene regulation and cellular functions. Through a CRISPR KO screen, we identified miR-940 as a negative regulator of ferroptosis. Overexpression of miR-940 in several cell lines consistently suppressed ferroptosis induced by system xc- inhibition. Notably, multiple cancer patient cohorts with elevated miR-940 levels exhibit reduced survival. Integrated bioinformatic, transcriptomic, and proteomic analyses revealed that miR-940 decreases the expression of ACSL4, LPCAT3, DMT1, and NCOA4, and simultaneously increases levels of GPX4. Pharmacological inhibition of GPX4 attenuated the protective effect of miR-940, indicating that its primary anti-ferroptotic activity is mediated through GPX4. Overall, this gene rewiring is associated with reduced levels of redox-active iron and diminished lipid peroxidation, consistent with ferroptosis suppression. These findings suggest that miR-940 coordinates ferroptosis inhibition, which presents a novel regulatory layer for therapeutic exploration in susceptible cancers.

cell biology↗

bioRxiv2023

TNF-NFkB-p53 axis restricts in vivo survival of hPSC-derived dopamine neuron

Ongoing, first-in-human clinical trials illustrate the feasibility and translational potential of human pluripotent stem cell (hPSC)-based cell therapies in Parkinsons disease (PD). However, a major unresolved challenge in the field is the extensive cell death following transplantation with <10% of grafted dopamine neurons surviving. Here, we performed a pooled CRISPR/Cas9 screen to enhance survival of postmitotic dopamine neurons in vivo. We identified p53-mediated apoptotic cell death as major contributor to dopamine neuron loss and uncovered a causal link of TNFa-NF{kappa}B signaling in limiting cell survival. As a translationally applicable strategy to purify postmitotic dopamine neurons, we performed a cell surface marker screen that enabled purification without the need for genetic reporters. Combining cell sorting with adalimumab pretreatment, a clinically approved and widely used TNFa inhibitor, enabled efficient engraftment of postmitotic dopamine neurons leading to extensive re-innervation and functional recovery in a preclinical PD mouse model. Thus, transient TNFa inhibition presents a clinically relevant strategy to enhance survival and enable engraftment of postmitotic human PSC-derived dopamine neurons in PD. HighlightsO_LIIn vivo CRISPR-Cas9 screen identifies p53 limiting survival of grafted human dopamine neurons. C_LIO_LITNF-NF{kappa}B pathway mediates p53-dependent human dopamine neuron death C_LIO_LICell surface marker screen to enrich human dopamine neurons for translational use. C_LIO_LIFDA approved TNF-alpha inhibitor rescues in vivo dopamine neuron survival with in vivo function. C_LI

neuroscience↗

bioRxiv2022

Combined small molecule treatment accelerates timing of maturation in human pluripotent stem cell-derived neurons

The maturation of human pluripotent stem cell (hPSC)-derived neurons mimics the protracted timing of human brain development, extending over months and years to reach adult-like function. Prolonged in vitro maturation presents a major challenge to stem cell-based applications in modeling and treating neurological disease. We designed a high-content imaging assay based on morphological and functional readouts in hPSC-derived cortical neurons to reveal underlying pathways and to identify chemicals capable of accelerating neuronal maturation. Probing a library of 2688 bioactive drugs, we identified multiple compounds that drive neuronal maturation including inhibitors of LSD1 and DOT1L and activators of calcium-dependent transcription. A cocktail of 4 factors GSK-2879552, EPZ-5676, NMDA and Bay K 8644, which we collectively termed GENtoniK, triggered maturation across all assays tested including measures of synaptic density, electrophysiology and transcriptomics. Remarkably, GENtoniK was similarly effective in enhancing neuronal maturation in 3D cortical organoids and in spinal motoneurons, and improved aspects of cell maturation in non-neural lineages such as melanocytes and pancreatic beta cells. These results demonstrate that the maturation of multiple hPSC-derived cell types can be enhanced by simple pharmacological intervention and suggests that some of the mechanisms controlling the timing of human maturation are shared across lineages.

neuroscience↗