Biology subjects

Bennett, N. K.

Publications and source records attributed to Bennett, N. K..

3 recordsLinked to original sources

bioRxiv2026

Genome-wide CRISPRi screen identifies basigin loss as protective in cardiac hypoxia

Cardiac function depends on continuous oxidative metabolism, rendering cardiomyocytes highly vulnerable to oxygen deprivation. Here, we performed a genome-wide CRISPR interference (CRISPRi) screen in human iPSC-derived cardiomyocytes to identify genes that modulate survival during chronic hypoxia. This screen revealed that knockdown of basigin (BSG), a chaperone for the monocarboxylate transporters MCT1 and MCT4, confers robust protection. Canonically, hypoxic cells suppress pyruvate dehydrogenase (PDH) activity to reduce the oxidation of major fuel sources, thereby limiting TCA cycle flux, lowering oxygen consumption, and minimizing reactive oxygen species generated by an overly reduced electron transport chain (ETC). In contrast, we found that BSG inhibition reverses this response, prioritizing ATP maintenance during hypoxia and enhancing cardiomyocyte survival. Mechanistically, BSG loss restricts lactate efflux, leading to decreased PDH phosphorylation and increased glucose uptake for oxidation. Consistent with this, ETC subunits are more essential under hypoxia, highlighting cardiomyocytes unusual reliance on aerobic ATP production even when oxygen is limited. These findings challenge prevailing models of hypoxic adaptation by revealing cardiomyocyte-specific bioenergetic requirements and motivating future therapeutic efforts.

cell biology↗

bioRxiv2025

Genetic regulators of neuronal survival across metabolic environments

Cellular energy metabolism and oxygen availability shape neuronal function and vulnerability, yet the genetic regulators of these metabolic processes in human neurons remain incompletely understood. Here, we performed CRISPR interference (CRISPRi) screens in human induced pluripotent stem cell (iPSC)-derived neurons across four distinct metabolic conditions and at three physiologically relevant oxygen tensions. This combinatorial approach enabled systematic interrogation of gene-environment interactions that govern neuronal metabolic adaptation. We identified genes--including genes associated with Leigh syndrome and autism spectrum disorder--whose importance for cell survival is highly sensitive to environmental context, revealing potential mechanisms underlying metabolic specification and selective neuronal vulnerability in neurological disorders. Our screens also uncovered regulators of neuronal glycolysis, including KIAA1429 and MAPT among others, which are previously uncharacterized modulators of neuronal glucose utilization and metabolic flexibility. Our work nominates candidate metabolic interventions and gene targets for enhancing neuronal resilience under hypoxic or nutrient-limited conditions.

systems biology↗

bioRxiv2023

Systems-level analyses dissociate genetic regulators of reactive oxygen species and energy production

Respiratory chain dysfunction can decrease ATP and increase reactive oxygen species (ROS) levels. Despite the importance of these metabolic parameters to a wide range of cellular functions and disease, we lack an integrated understanding of how they are differentially regulated. To address this question, we adapted a CRISPRi- and FACS-based platform to compare the effects of respiratory gene knockdown on ROS to their effects on ATP. Focusing on genes whose knockdown is known to decrease mitochondria-derived ATP, we showed that knockdown of genes in specific respiratory chain complexes (I, III and CoQ10 biosynthesis) increased ROS, whereas knockdown of other low ATP hits either had no impact (mitochondrial ribosomal proteins) or actually decreased ROS (complex IV). Moreover, although shifting metabolic conditions profoundly altered mitochondria-derived ATP levels, it had little impact on mitochondrial or cytosolic ROS. In addition, knockdown of a subset of complex I subunits--including NDUFA8, NDUFB4, and NDUFS8--decreased complex I activity, mitochondria-derived ATP and supercomplex level, but knockdown of these genes had differential effects on ROS. Conversely, we found an essential role for ether lipids in the dynamic regulation of mitochondrial ROS levels independent of ATP. Thus, our results identify specific metabolic regulators of cellular ATP and ROS balance that may help dissect the roles of these processes in disease and identify therapeutic strategies to independently target energy failure and oxidative stress. SignificanceMitochondrial respiration generates both energy (ATP) and reactive oxygen species (ROS). Insufficient energy and increased ROS from respiratory chain dysfunction may be central to the pathophysiology of neurodegenerative diseases and aging. We established a screening platform using CRISPR and fluorescent-cell sorting to compare the impact of decreasing respiratory chain proteins on ROS and ATP levels. The results provide the first systems-level analysis of how ROS and ATP are differentially regulated, and identify genes and respiratory chain complexes that can manipulate each independently. These findings advance our understanding of the relative contributions of ATP and ROS to disease pathophysiology, and guide the development of therapies to preserve energy while minimizing ROS.

systems biology↗