Mitochondrial DNA Depletion Research Articles

Arginine-methylated c-Myc affects mitochondrial mitophagy in mouse acute kidney injury via Slc25a24.

The transcription factor methylated c-Myc heterodimerizes with MAX to modulate gene expression, and plays an important role in energy metabolism in kidney injury but the exact mechanism remains unclear. Mitochondrial solute transporter Slc25a24 imports ATP into mitochondria and is central to energy metabolism. Gene Expression Omnibus data analysis reveals Slc25a24 and c-Myc are consistently upregulated in all the acute kidney injury (AKI) cells. Pearson correlation analysis also shows that Slc25a24 and c-Myc are strongly correlated (⍴ > 0.9). Mutant arginine methylated c-Myc (R299A and R346A) reduced its combination with MAX when compared with the wild type of c-Myc. On the other hand, the Slc25a24 levels were also correspondingly reduced, which induced the downregulation of ATP production. The results promoted reactive oxygen species(ROS) production and mitophagy generation. The study revealed that the c-Myc overexpression manifested the most pronounced mitochondrial DNA depletion. Additionally, the varied levels of mitochondrial proteins like TIM23, TOM20, and PINK1 in each group, particularly the elevated levels of PINK1 in AKI model groups and lower levels of TIM23 and TOM20 in the c-Myc overexpression group, suggest potential disruptions in mitochondrial dynamics and homeostasis, indicating enhanced mitophagy or mitochondrial loss. Therefore, arginine-methylated c-Myc affects mouse kidney injury by regulating mitochondrial ATP and ROS, and mitophagy via Slc25a24.

Two novel SUCLA2 variants cause mitochondrial DNA depletion syndrome, type 5 in two siblings.

Mitochondrial DNA depletion syndrome (MDS), characterized by succinate-CoA ligase deficiency and loss of mitochondrial DNA (mtDNA), is caused by specific variants in nuclear genes responsible for mtDNA maintenance. SUCLA2-related mitochondrial DNA depletion syndrome, type 5 (MTDPS-5), presents as a rare, severe early progressive encephalomyopathy. This report investigates a new family exhibiting clinical manifestations of MTDPS-5 and elucidates the genetic basis of this disorder. In two affected siblings, a novel maternally inherited nonsense variant [c.1234C>T (p.Arg412*)] in the SUCLA2 gene and a unique paternally inherited indel variant (g.48569263-48571020del1758insATGA) were identified. Additionally, the siblings exhibited blood mtDNA content lower than 33% compared to age-matched controls. These findings underscore the importance of assessing SUCLA2 variants in patients with severe early progressive encephalomyopathy, even in the absence of methylmalonic aciduria or mtDNA loss, thereby broaden the mutational spectrum of this gene.

Diterpenoid honatisine overcomes temozolomide resistance in glioblastoma by inducing mitonuclear protein imbalance through disruption of TFAM-mediated mtDNA transcription

BackgroundGlioblastoma (GBM) represents as the most formidable intracranial malignancy. The systematic exploration of natural compounds for their potential applications in GBM therapy has emerged as a pivotal and fruitful avenue of research. PurposeIn the present study, a panel of 96 diterpenoids was systematically evaluated as a repository of potential antitumour agents. The primary objective was to discern their potency in overcoming resistance to temozolomide (TMZ). Through an extensive screening process, honatisine, a heptacyclic diterpenoid alkaloid, emerged as the most robust candidate. Notably, honatisine exhibited remarkable efficacy in patient-derived primary and recurrent GBM strains. Subsequently, we subjected this compound to comprehensive scrutiny, encompassing GBM cultured spheres, GBM organoids (GBOs), TMZ-resistant GBM cell lines, and orthotopic xenograft mouse models of GBM cells. ResultsOur investigative efforts delved into the mechanistic underpinnings of honatisine's impact. It was discerned that honatisine prompted mitonuclear protein imbalance and elicited the mitochondrial unfolded protein response (UPRmt). This effect was mediated through the selective depletion of mitochondrial DNA (mtDNA)-encoded subunits, with a particular emphasis on the diminution of mitochondrial transcription factor A (TFAM). The ultimate outcome was the instigation of deleterious mitochondrial dysfunction, culminating in apoptosis. Molecular docking and surface plasmon resonance (SPR) experiments validated honatisine's binding affinity to TFAM within its HMG-box B domain. This binding may promote phosphorylation of TFAM and obstruct the interaction of TFAM bound to heavy strand promoter 1 (HSP1), thereby enhancing Lon-mediated TFAM degradation. Finally, in vivo experiments confirmed honatisine's antiglioma properties. Our comprehensive toxicological assessments underscored its mild toxicity profile, emphasizing the necessity for a thorough evaluation of honatisine as a novel antiglioma agent. ConclusionIn summary, our data provide new insights into the therapeutic mechanisms underlying honatisine's selective inducetion of apoptosis and its ability to overcome chemotherapy resistance in GBM. These actions are mediated through the disruption of mitochondrial proteostasis and function, achieved by the inhibition of TFAM-mediated mtDNA transcription. This study highlights honatisine's potential as a promising agent for glioblastoma therapy, underscoring the need for further exploration and investigation.

FBXL4 mutation-caused mitochondrial DNA depletion syndrome is driven by BNIP3/BNIP3L-dependent excessive mitophagy

Encephalomyopathic mitochondrial DNA (mtDNA) depletion syndrome 13 (MTDPS13) is an autosomal recessive disorder arising from biallelic F-box and leucine-rich repeat (LRR) protein 4 (FBXL4) gene mutations. Recent advances have shown that excessive BCL2 interacting protein 3 (BNIP3)/ BCL2 interacting protein 3 like (BNIP3L)-dependent mitophagy underlies the molecular pathogenesis of MTDPS13. Here, we provide an overview of these groundbreaking findings and discuss potential therapeutic strategies for this fatal disease.

Safety and efficacy of deoxycytidine/deoxythymidine combination therapy in mitochondrial DNA depletion disorders: Preliminary results

Safety and efficacy of deoxycytidine/deoxythymidine combination therapy in mitochondrial DNA depletion disorders: Preliminary results

Consequences of mitochondrial DNA depletion in microglial cells

AbstractBackgroundMitochondrial dysfunction is an early and prominent feature of Alzheimer’s disease (AD). We have recently published that lower brain mitochondrial DNA copy number (mtDNAcn) is associated with a greater odds of AD neuropathological change and worse cognitive performance. As it is known that microglial cells play an important role in AD, we want to address how a reduction in mtDNAcn may affect microglial function.Methodsmicroglial BV2 cells were treated with ethidium bromide (etbr) (1ug/ml) for 5 days to achieve a 95% reduction of mitochondrial‐encoded genes expression. Cells were characterized by RNAseq and Seahorse experiments. BV2 cells were challenged with latex beads and 10uM zymosan‐pHrodo for 24 hours and phagocytosis was analyzed by flow cytometry. BV2 cells were stimulated with LPS (100ng/ml) for 3 hours to measure cytokine release by qPCR and ELISA. After BV2 stimulation, fresh media (without LPS or etbr) was conditioned for 6 hours and collected to treat neurons (SH‐SY5Y cells) and human primary astrocytes for 24 hours. RNA and protein samples were collected.ResultsmtDNAcn reduction led to a dramatic reduction in oxidative phosphorylation and a mild reduction in proliferation. RNAseq data showed an increase in the hypoxia signature and cellular senescence, coupled with a reduction in biosynthetic process and response to interferon. No changes were observed in phagocytic capacity. However, after LPS stimulation, etbr‐treated cells showed a reduction in the production of IL1B and IL6 cytokines, suggesting an impairment in the response to challenge. Neurons exposed to media from etbr‐treated BV2 cells showed an increase in MAPT and APOE expression. Samples from astrocytes are currently being analyzed.ConclusionsmtDNAcn reduction impairs mitochondrial respiration, which affects the production of cytokines in response to stimulus and leads to cell senescence in microglial cells. Cytokines released by microglia affected neuronal expression of AD‐related genes.

Methylmalonic aciduria as a biochemical marker for mitochondrial DNA depletion syndrome in patients with developmental delay and movement disorders: a case series

Methylmalonic aciduria as a biochemical marker for mitochondrial DNA depletion syndrome in patients with developmental delay and movement disorders: a case series

Impact of N221S missense mutation in human ribonucleotide reductase small subunit b on mitochondrial DNA depletion syndrome

The impact of N221S mutation in hRRM2B gene, which encodes the small subunit of human ribonucleotide reductase (RNR), on RNR activity and the pathogenesis of mitochondrial DNA depletion syndrome (MDDS) was investigated. Our results demonstrate that N221 mutations significantly reduce RNR activity, suggesting its role in the development of MDDS. We proposed an allosteric regulation pathway involving a chain of three phenylalanine residues on the αE helix of RNR small subunit β. This pathway connects the C-terminal loop of β2, transfers the activation signal from the large catalytic subunit α to β active site, and controls access of oxygen for radical generation. N221 is near this pathway and likely plays a role in regulating RNR activity. Mutagenesis studies on residues involved in the phenylalanine chain and the regulation pathway were conducted to confirm our proposed mechanism. We also performed molecular dynamic simulation and protein contact network analysis to support our findings. This study sheds new light on RNR small subunit regulation and provides insight on the pathogenesis of MDDS.

Long term survival and abnormal liver fat accumulation in mice with specific thymidine kinase 2 deficiency in liver tissue.

Deficiency in thymidine kinase 2 (TK2) causes mitochondrial DNA depletion. Liver mitochondria are severely affected in Tk2 complete knockout models and have been suggested to play a role in the pathogenesis of the Tk2 knockout phenotype, characterized by loss of hypodermal fat tissue, growth retardation and reduced life span. Here we report a liver specific Tk2 knockout (KO) model to further study mechanisms contributing to the phenotypic changes associated with Tk2 deficiency. Interestingly, the liver specific Tk2 KO mice had a normal life span despite a much lower mtDNA level in liver tissue. Mitochondrial DNA encoded peptide COXI did not differ between the Tk2 KO and control mice. However, the relative liver weight was significantly increased in the male Tk2 KO mouse model. Histology analysis indicated an increased lipid accumulation. We conclude that other enzyme activities can partly compensate Tk2 deficiency to maintain mtDNA at a low but stable level throughout the life span of the liver specific Tk2 KO mice. The lower level of mtDNA was sufficient for survival but led to an abnormal lipid accumulation in liver tissue.

Mitochondrial DNA release mediated by TFAM deficiency promotes copper-induced mitochondrial innate immune response via cGAS-STING signalling in chicken hepatocytes

Copper (Cu) is pollution metal that is a global concern due to its toxic effects. A recent study found that the release of mitochondrial DNA (mtDNA) into the cytoplasm can activate the innate immune response, but the exact mechanisms underlying the effect of Cu exposure remains unknown. In this study, we identified that the reduction in transcription Factor A (TFAM) led to mtDNA leakage into the cytoplasm under Cu exposure in hepatocytes, accompanied by the activation of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway-mediated innate immunity (increased expression of cGAS, STING, TANK-binding kinase-1 (TBK1), and interferon regulatory factor-3 (IRF3)) genes and proteins, and enhanced phosphorylation levels of TBK1 and IRF3). Subsequently, silencing TFAM (siTFAM) significantly aggravated mtDNA release and the innate immune response under Cu treatment. Mitochondrial DNA depletion alleviated Cu-induced innate immunity in hepatocytes, while mtDNA transfection further enhanced the innate immune response. Notably, the inhibition of STING effectively alleviated the phosphorylation levels of the TBK1 and IRF3 proteins induced by Cu, while the upregulation of STING aggravated the Cu-induced innate immunity. Furthermore, EtBr and H-151(a STING inhibitor) treatment dramatically reversed the effect of TFAM depletion on the sharpened innate immune response induced by Cu via the cGAS-STING pathway. In general, these findings demonstrated the TFAM deficiency promotes innate immunity by activating the mtDNA-cGAS-STING signalling pathway under Cu exposure in hepatocytes, providing new insight into Cu toxicology.

Drosophila Mpv17 forms an ion channel and regulates energy metabolism

Mutations in MPV17 are a major contributor to mitochondrial DNA (mtDNA) depletion syndromes, a group of inherited genetic conditions due to mtDNA instability. To investigate the role of MPV17 in mtDNA maintenance, we generated and characterized a Drosophila melanogaster Mpv17 (dMpv17) KO model showing that the absence of dMpv17 caused profound mtDNA depletion in the fat body but not in other tissues, increased glycolytic flux and reduced lifespan in starvation. Accordingly, the expression of key genes of glycogenolysis and glycolysis was upregulated in dMpv17 KO flies. In addition, we demonstrated that dMpv17 formed a channel in planar lipid bilayers at physiological ionic conditions, and its electrophysiological hallmarks were affected by pathological mutations. Importantly, the reconstituted channel translocated uridine but not orotate across the membrane. Our results indicate that dMpv17 forms a channel involved in translocation of key metabolites and highlight the importance of dMpv17 in energy homeostasis and mitochondrial function.

Let's make it clear: systematic exploration of mitochondrial DNA- and RNA-protein complexes by complexome profiling.

Complexome profiling (CP) is a powerful tool for systematic investigation of protein interactors that has been primarily applied to study the composition and dynamics of mitochondrial protein complexes. Here, we further optimized this method to extend its application to survey mitochondrial DNA- and RNA-interacting protein complexes. We established that high-resolution clear native gel electrophoresis (hrCNE) is a better alternative to preserve DNA- and RNA-protein interactions that are otherwise disrupted when samples are separated by the widely used blue native gel electrophoresis (BNE). In combination with enzymatic digestion of DNA, our CP approach improved the identification of a wide range of protein interactors of the mitochondrial gene expression system without compromising the detection of other multiprotein complexes. The utility of this approach was particularly demonstrated by analysing the complexome changes in human mitochondria with impaired gene expression after transient, chemically induced mitochondrial DNA depletion. Effects of RNase on mitochondrial protein complexes were also evaluated and discussed. Overall, our adaptations significantly improved the identification of mitochondrial DNA- and RNA-protein interactions by CP, thereby unlocking the comprehensive analysis of a near-complete mitochondrial complexome in a single experiment.

Infantile onset encephalomyopathy, retinopathy, optic atrophy, and mitochondrial DNA depletion associated with a novel pathogenic DHX16 variant.

We studied a patient with mitochondrial DNA depletion in skeletal muscle and a multiorgan phenotype, including fatal encephalomyopathy, retinopathy, optic atrophy, and sensorineural hearing loss. Instead of pathogenic variants in the mitochondrial maintenance genes, we identified previously unpublished variant in DHX16 gene, a de novo heterozygous c.1360C>T (p. Arg454Trp). Variants in DHX16 encoding for DEAH-box RNA helicase have previously been reported only in five patients with a phenotype called as neuromuscular oculoauditory syndrome including developmental delay, neuromuscular symptoms, and ocular or auditory defects with or without seizures. We performed functional studies on patient-derived fibroblasts and skeletal muscle revealing, that the DHX16 expression was decreased. Clinical features together with functional data suggest, that our patient's disease is associated with a novel pathogenic DHX16 variant, and mtDNA depletion could be a secondary manifestation of the disease.

FBXL4 mutations cause excessive mitophagy via BNIP3/BNIP3L accumulation leading to mitochondrial DNA depletion syndrome.

Mitochondria are essential organelles found in eukaryotic cells that play a crucial role in ATP production through oxidative phosphorylation (OXPHOS). Mitochondrial DNA depletion syndrome (MTDPS) is a group of genetic disorders characterized by the reduction of mtDNA copy number, leading to deficiencies in OXPHOS and mitochondrial functions. Mutations in FBXL4, a substrate-binding adaptor of Cullin 1-RING ubiquitin ligase complex (CRL1), are associated with MTDPS, type 13 (MTDPS13). Here, we demonstrate that, FBXL4 directly interacts with the mitophagy cargo receptors BNIP3 and BNIP3L, promoting their degradation through the ubiquitin-proteasome pathway via the assembly of an active CRL1FBXL4 complex. However, MTDPS13-associated FBXL4 mutations impair the assembly of an active CRL1FBXL4 complex. This results in a notable accumulation of BNIP3/3L proteins and robust mitophagy even at basal levels. Excessive mitophagy was observed in Knockin (KI) mice carrying a patient-derived FBXL4 mutation and cortical neurons (CNs)-induced from MTDPS13 patient human induced pluripotent stem cells (hiPSCs). In summary, our findings suggest that abnormal activation of BNIP3/BNIP3L-dependent mitophagy impairs mitochondrial homeostasis and underlies FBXL4-mutated MTDPS13.

Mitochondrial protein MPV17 promotes beta-cell apoptosis in diabetogenesis.

MPV17 is a mitochondrial inner membrane protein, and its deficiency can cause mitochondrial DNA (mtDNA) depletion, increase reactive oxygen species (ROS), and promote apoptosis in several cell types, suggesting that MPV17 plays a protective role in cells although the underlying mechanism remains unknown. To test whether MPV17 is also protective in diabetic kidney disease, we treated MPV17-deficient mice with streptozotocin (STZ) and surprisingly found that they were resistant to diabetes. MPV17 deficiency was also found to confer resistance to the diabetes induced by an insulin mutation (Ins2Akita), which represents a mouse model of monogenic diabetes characterized by proinsulin misfolding and beta-cell failure. In both STZ and Ins2Akita models, Mpv17 mutants had significantly less severe beta-cell loss and apoptosis compared with the wild-type mice. We next showed that Mpv17 is expressed in beta-cells of mice normally, suggesting that MPV17 acts beta-cells autonomously to facilitate apoptosis. Consistently, Mpv17 knockdown improved the viability and ameliorated the apoptosis of cultured MIN6 cells treated with STZ and palmitic acid (PA), respectively, accompanied by prevention of caspase 3 activation. The proapoptotic effect of MPV17 in beta-cells is in contrast with its known anti-apoptotic effect in other cell types. Thus, we have identified a novel regulator of beta-cell death in diabetes development.

Mitochondrial depletion syndrome type 3: the Lebanese variant.

Introduction: Mitochondrial DNA depletion syndrome type 3 is an emerging disorder linked to variants in the deoxyguanosine kinase gene, which encodes for mitochondrial maintenance. This autosomal recessive disorder is frequent in the Middle East and North Africa. Diagnosis is often delayed due to the non-specificity of clinical presentation with cerebro-hepatic deterioration. The only therapeutic option is liver transplantation, although the value of this remains debatable. Methods: We describe the clinical, biochemical, and molecular profiles of Lebanese patients with this rare disorder. We also present a review of all cases from the Middle East and North Africa. Results: All Lebanese patients share a unique mutation, unreported in other populations. Almost half of patients worldwide originate from the Middle East and North Africa, with cases reported from only 7 of the 21 countries in this region. Clinical presentation is heterogeneous, with early-onset neurological and hepatic signs. Liver failure and lactic acidosis are constants. Several variants can be identified in each population; a unique c.235C>T p. (Gln79*) pathogenic variant is found in Lebanese patients. Outcome is poor, with death before 1year of age. Conclusion: The pathogenic nonsense variant c.235C>T p. (Gln79*) in the deoxyguanosine kinase gene may be considered a founder mutation in Lebanon. Further genotypic delineation of this devastating disorder in populations with high consanguinity rates is needed.

The disease-causing mutation p.F907I reveals a novel pathogenic mechanism for POLγ-related diseases

Mutations in the catalytic domain of mitochondrial DNA polymerase γ (POLγ) cause a broad spectrum of clinical conditions. POLγ mutations impair mitochondrial DNA replication, thereby causing deletions and/or depletion of mitochondrial DNA, which in turn impair biogenesis of the oxidative phosphorylation system. We here identify a patient with a homozygous p.F907I mutation in POLγ, manifesting a severe clinical phenotype with developmental arrest and rapid loss of skills from 18 months of age. Magnetic resonance imaging of the brain revealed extensive white matter abnormalities, Southern blot of muscle mtDNA demonstrated depletion of mtDNA and the patient deceased at 23 months of age. Interestingly, the p.F907I mutation does not affect POLγ activity on single-stranded DNA or its proofreading activity. Instead, the mutation affects unwinding of parental double-stranded DNA at the replication fork, impairing the ability of the POLγ to support leading-strand DNA synthesis with the TWINKLE helicase. Our results thus reveal a novel pathogenic mechanism for POLγ-related diseases.

Hepatic presentations of mitochondrial DNA depletion syndrome in children: A single tertiary liver centre experience.

Mitochondrial DNA depletion syndromes (MDDS) are a heterogeneous group and the hepato-cerebral phenotype is highly variable. A single centre retrospective study of all patients with MDDS presenting between January 2002 and September 2019. In total, 24 (13 male) children were identified: 7 POLG, 7 DGUOK, and 10 MPV17. Median age at presentation was 3 months (0.06-189). Sixteen had acute liver failure (ALF) and eight chronic cholestasis and/or raised transaminases. Four POLG patients developed liver injury after starting sodium valproate; Six DGUOK patients had neonatal ALF (median age 12 days), liver involvement developed at a median age of 2.5 and 11 months with MPV17 and POLG patients, respectively. Eighteen patients showed neurological involvement. Liver histology from 10 patients showed variable degrees of necrosis, steatosis, cholestasis, and fibrosis. Mitochondrial respiratory chain enzymology was abnormal in 5. Seventeen patients died at a median age of 8 months (range, 1-312) after a median time of 5.6 months from presentation: 5/7 POLG at 53 months, 7/7 DGUOK at 8 months and 5/10 MPV17 at 8 months. Three patients with MPV17 mutations received liver transplant (LT) at a median age of 24 months (range 5-132): all alive at 19, 18 and 3 years post-LT. Mutations in DGUOK and MPV17 genes are associated with a severe clinical phenotype characterised by early-onset/neonatal ALF or rapidly progressive cholestasis and death before 12 months of age. A subset of MPV17 patients was amenable to LT. Consideration for LT in infantile ALF remains difficult and rapid genetic testing is advised.

Mitochondrial DNA Depletion syndrome 1 (MNGIE type) - a rare cause of premature ovarian failure?

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Ataxia Telangiestasia Mutated (ATM) Inhibition Disrupts Nuclear And Mitochondrial Homeostasis In Pediatric Nonalcoholic Fatty Liver Disease (PNAFLD)

BACKGROUND: The pathophysiology of PNAFLD is important to understand in order to improve outcomes. Integration of critical components including metabolic stress, inflammation, organelle function, and DNA damage and repair should be particularly critical for this purpose. To emphasize the contribution of DNA damage response and cell survival mechanisms on PNAFLD outcomes during the period of active liver growth, we focused on the ATM pathway. In toxic liver injury settings, replenishment of ATM overcomes restrictions in liver homeostasis and regeneration. METHODS and RESULTS: We undertook a study of PNAFLD in a cohort of children under 12 years of age to represent the period of active liver growth (N=47). Demographic details were noted including age, gender, ethnic origin and duration of obesity as defined by BMI greater than 85th percentile. B iopsies were examined for NAFLD activity score (NAS) components steatosis, ballooning and inflammation as well as fibrosis. Mitochondrial DNA content was quantitated by qPCR for the mitochondrial gene, TL1, vs the nuclear gene, RNAseP. Ploidy class distributions was evaluated by cytofluorimetric analysis of nuclei stained with Hoechst dye. Cell growth-arrest was examined by immunostaining of p21. ATM expression was quantitated by qPCR for ATM relative to GAPDH. Mitochondrial homeostasis in mice with PNAFLD was evaluated by electron microscopy and Western Blot of fission and fusion proteins. Of the 47 children in the cohort, 74% were male, 26% female; 85% hispanic, 11% white, black or asian, and 4% unspecified. Mean BMI of the cohort was 94±7th percentile. The duration of obesity until time of liver biopsy was 4±2 years. 61% displayed simple steatosis or fatty liver (FL) with NAS less than 5, and 39% had steatohepatitis (NASH), with NAS equal to or greater than 5. Significantly, 50% of children in the cohort had fibrosis at the time of liver biopsy. Disease progression was associated with dyregulated ATM expression as evidenced by less ATM mRNA expression in FL compared to healthy controls (obtained from NIDDK supported biorepository LTPADS from the University of Minnesota) which further declined with NASH. This was associated with greater degree of mitochondrial DNA depletion in NASH vs FL, compared to healthy controls, which is dependent on ATM. Consequences of mitochondrial depletion extended to increased p21 mediated cell growth arrest and pathological polyploidy. In modelling of PNAFLD in mice, exposure of weanling mice to high fat diet plus low dose CCl4 plus ATM kinase antagonism for 4 weeks reproduced hepatic steatosis, inflammation ballooning and fibrogenesis. Moreover, there was disruption of mitochondrial homeostatis including fission and fusion. CONCLUSION: Disruption of ATM is particularly critical for PNAFLD in early liver growth stage by increasing susceptibility to nuclear and mitochondrial injury. These insights should advance translational and clinical studies in this area. 1K08DK125881-01A1 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.