Biology subjects

Crocker, A.

Publications and source records attributed to Crocker, A..

6 recordsLinked to original sources

bioRxiv2026

Suppressive Genetic Interactions Between Haploinsufficient Mitochondrial Genes Encoded in the 22q11.2 Microdeletion Locus Define Brain and Cardiac Phenotypes

Genomic copy number variations, such as the 22q11.2 microdeletion syndrome, cause pleiotropic disorders that affect diverse organ systems and disrupt neurodevelopment. Deletions of the 22q11.2 locus reduce the dosage of up to 46 protein coding genes, raising questions about the identity of haploinsufficient genes and their genetic interactions contributing to 22q11.2 phenotypes. Here, we dissect functional and molecular relationships between two genes encoded within the 22q11.2 locus: the mitochondrial ribosomal protein gene MRPL40 and the mitochondrial citrate transporter SLC25A1. We show that a MRPL40 null mutation disrupts mitochondrial translation, impairs respiration, and affects multiple components of the SLC25A1 interactome including factors required for lipid metabolism, mitochondrial ribosome subunits, and the mitochondrial RNA processing machinery. In silico coessentiality network analysis revealed correlated and anticorrelated fitness interactions linking MRPL40 and SLC25A1 to mitochondrial translation, intermediate carbon metabolism, and interferon signaling. We determined that Mrpl40-null mutations are embryonic lethal in mice, but Mrpl40-/+ mice are viable and displayed embryonic cardiac development and adult behavioral phenotypes. Similarly, Slc25a1+/- animals showed embryonic cardiac developmental defects but lacked the adult behavioral phenotypes observed in Mrpl40-/+ mice. Surprisingly, transheterozygotic Slc25a1+/-;Mrpl40-/+ mice suppressed or mitigated cardiac development, behavioral, and brain transcriptome phenotypes observed in single heterozygotic animals. These results reveal that MRPL40 and SLC25A1 are haploinsufficient genes within the 22q11.2 locus that genetically and biochemically interact to define tissue development and physiology. Our findings provide a framework for understanding the complexity and type of gene dosage interactions within the 22q11.2 deletion syndrome locus.

neuroscience↗

bioRxiv2025

Brain Mecp2 Gene Dosage and Gene Therapy Shape Multi-Omic Signatures and Biomarkers in Rett Syndrome

Rett syndrome (RTT) is a neurodevelopmental disorder caused by MECP2 mutations. Like other genetic neurodevelopmental disorders, it lacks protein biomarkers to evaluate disease and therapeutic outcomes. We present a strategy to define putative biomarkers of MeCP2 dysfunction in brain with potential to delineate mechanisms and monitor therapeutic interventions. This strategy relies on a library of proteins responsive to Mecp2 gene dosage and correlated with molecular and clinical outcomes after AAV9-mediated MECP2 gene therapy in Mecp2-KO mice. Gene rescue restored MeCP2 in brain, improved clinical phenotypes, and reverted transcriptome and proteome abnormalities. We identified 327 shared proteins among 1852 cortical and hippocampal proteins responsive to Mecp2/MECP2. Of these, 119 also displayed Mecp2/MECP2-dependent transcript changes. Both the Mecp2-responsive proteome and transcript-protein pairs were enriched in synaptic and metabolic pathways, including central carbon and NAD+ metabolism. We used this therapy-responsive protein library to guide selection of candidate cerebrospinal fluid (CSF) biomarkers in RTT. CSF composition from neurotypical and RTT groups was analyzed using ultrasensitive nucleic acid-based multiplexed ELISA. Twenty-eight proteins were altered in RTT, nine overlapping with Mecp2 dosage- and therapy-sensitive proteins. Multivariate regression linked several candidates to Mecp2/MeCP2 abundance and phenotypic improvement in mice. This paradigm provides a rigorous molecular systems-level framework integrating genetics, preclinical gene therapy, and clinical metrics to define robust cross-species putative biomarkers and possible mechanisms in RTT, with potential applicability to other neurodevelopmental disorders. One Sentence SummaryGenetic Identification of cross-species biomarkers and mechanisms in Rett Syndrome

neuroscience↗

bioRxiv2023

Transcriptional profiling of Drosophila male-specific P1 (pC1) neurons

In Drosophila melanogaster, the P1 (pC1) cluster of male-specific neurons both integrates sensory cues and drives or modulates behavioral programs such as courtship, in addition to contributing to a social arousal state. The behavioral function of these neurons is linked to the genes they express, which underpin their capacity for synaptic signaling, neuromodulation, and physiology. Yet, P1 (pC1) neurons have not been fully characterized at the transcriptome level. Moreover, it is unknown how the molecular landscape of P1 (pC1) neurons acutely changes after flies engage in social behaviors, where baseline P1 (pC1) neural activity is expected to increase. To address these two gaps, we use single cell-type RNA sequencing to profile and compare the transcriptomes of P1 (pC1) neurons harvested from socially paired versus solitary male flies. Compared to control transcriptome datasets, we find that P1 (pC1) neurons are enriched in 2,665 genes, including those encoding receptors, neuropeptides, and cell-adhesion molecules (dprs/DIPs). Furthermore, courtship is characterized by changes in[~] 300 genes, including those previously implicated in regulating behavior (e.g. DopEcR, Oct{beta}3R, Fife, kairos, rad). Finally, we identify a suite of genes that link conspecific courtship with the innate immune system. Together, these data serve as a molecular map for future studies of an important set of higher-order and sexually-dimorphic neurons.

neuroscience↗

bioRxiv2023

Systemic Metabolic and Mitochondrial Defects in Rett Syndrome Models

Genes mutated in monogenic neurodevelopmental disorders are broadly expressed. This observation supports the concept that monogenic neurodevelopmental disorders are systemic diseases that profoundly impact neurodevelopment. We tested the systemic disease model focusing on Rett syndrome, which is caused by mutations in MECP2. Transcriptomes and proteomes of organs and brain regions from Mecp2-null mice as well as diverse MECP2-null male and female human cells were assessed. Widespread changes in the steady-state transcriptome and proteome were identified in brain regions and organs of presymptomatic Mecp2-null male mice as well as mutant human cell lines. The extent of these transcriptome and proteome modifications was similar in cortex, liver, kidney, and skeletal muscle and more pronounced than in the hippocampus and striatum. In particular, Mecp2- and MECP2-sensitive proteomes were enriched in synaptic and metabolic annotated gene products, the latter encompassing lipid metabolism and mitochondrial pathways. MECP2 mutations altered pyruvate-dependent mitochondrial respiration while maintaining the capacity to use glutamine as a mitochondrial carbon source. We conclude that mutations in Mecp2/MECP2 perturb lipid and mitochondrial metabolism systemically limiting cellular flexibility to utilize mitochondrial fuels.

neuroscience↗

bioRxiv2022

APOE Expression and Secretion are Modulated by Copper-Dependent and -Independent Mitochondrial Dysfunction

Mitochondria influence cellular function through both cell-autonomous and non-cell autonomous mechanisms, such as production of paracrine and endocrine factors. Here, we demonstrate that mitochondrial regulation of the secretome is more extensive than previously appreciated, as both genetic and pharmacological disruption of the electron transport chain caused upregulation of the Alzheimers disease risk factor apolipoprotein E (APOE) and other secretome components. This upregulation of secretory proteins was of a similar extent as modifications to the mitochondrial annotated proteome. Indirect disruption of the electron transport chain by gene editing of SLC25A mitochondrial membrane transporters as well as direct genetic and pharmacological disruption of either complexes I, III, or the copper-containing complex IV of the electron transport chain, elicited upregulation of APOE transcript, protein, and secretion, up to 49-fold. These APOE phenotypes were robustly expressed in diverse cell types and iPSC-derived human astrocytes as part of an inflammatory gene expression program. Moreover, age- and genotype-dependent decline in brain levels of respiratory complex I preceded an increase in APOE in the 5xFAD mouse model. We propose that mitochondria act as novel upstream regulators of APOE-dependent cellular processes in health and disease.

cell biology↗

bioRxiv2018

Systems Analysis of the 22q11.2 Microdeletion Syndrome Converges on a Mitochondrial Interactome Necessary for Synapse Function and Behavior

Neurodevelopmental disorders offer insight into synaptic mechanisms. To unbiasedly uncover these mechanisms, we studied the 22q11.2 syndrome, a recurrent copy number variant, which is the highest schizophrenia genetic risk factor. We quantified the proteomes of 22q11.2 mutant human fibroblasts and mouse brains carrying a 22q11.2-like defect, Df(16)A+/-. Molecular ontologies defined mitochondrial compartments and pathways as some of top ranked categories. In particular, we identified perturbations in the SLC25A1-SLC25A4 mitochondrial transporter interactome as associated with the 22q11.2 genetic defect. Expression of SLC25A1-SLC25A4 interactome components was affected in neuronal cells from schizophrenia patients. Furthermore, hemideficiency of the Drosophila SLC25A4 orthologue, dSLC25A4-sesB, affected synapse function and impaired sleep patterns in a neuronal-specific manner. These results identify a novel synaptic role of mitochondrial inner membrane solute transporters. We propose that mitochondria are among key organelles affected by genetic defects that increase the risk of neurodevelopmental disorders.

neuroscience↗