Biology subjects

Dolinsky, V. W.

Publications and source records attributed to Dolinsky, V. W..

9 recordsLinked to original sources

bioRxiv2026

Autophagy Cholesterol Axis Remodeling Supports Malignant Progression and Chemoresistance in Glioma

Glioma progression and resistance to temozolomide (TMZ) remain major clinical challenges. Here, we investigated whether dysregulated autophagy and cholesterol metabolism are coordinately remodeled during glioma progression and TMZ resistance. Tissue microarray analysis of astrocytoma and glioblastoma specimens revealed progressive autophagosome accumulation, reflected by increased LC3{beta} puncta, coupled with impaired autophagic flux compared with adjacent normal brain tissue. These alterations intensified with tumor grade and were associated with upregulation of farnesyl diphosphate synthase (FDPS), linking malignant progression to cholesterol pathway remodeling. TMZ-resistant (R) glioblastoma cells exhibited epithelial-to-mesenchymal transition, mitotic quiescence, and mitochondrial remodeling consistent with a therapy-tolerant phenotype. Bioenergetic profiling demonstrated reduced respiratory reserve, diminished ATP-linked respiration, and elevated proton leak, indicating constrained metabolic flexibility. In parallel, impaired autophagy flux was associated with suppression of de novo cholesterol synthesis and transcriptional downregulation of SREBP-2 and LDL-R. Comprehensive lipidomic profiling revealed marked cholesterol metabolic reprogramming in R cells, characterized by accumulation of specific cholesteryl esters, including CE 22:5, CE 22:6, CE 22:4, and CE 20:4, despite reduced cholesterol biosynthesis. Pharmacologic inhibition of the mevalonate pathway with simvastatin significantly altered cholesteryl ester profiles but failed to restore autophagy flux or sensitize R cells to TMZ-induced apoptosis, even under combined TMZ-simvastatin treatment. Lay AbstractAs gliomas progress from astrocytoma to glioblastoma, autophagy becomes dysregulated and cholesterol metabolism is rewired. This coordinated remodeling supports tumor survival, metabolic plasticity, and resistance to temozolomide therapy. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/697885v2_ufig1.gif" ALT="Figure 1000"> View larger version (79K): org.highwire.dtl.DTLVardef@1183dd2org.highwire.dtl.DTLVardef@82e20dorg.highwire.dtl.DTLVardef@c6c8dforg.highwire.dtl.DTLVardef@adb427_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsAutophagy flux blockade intensifies during progression from astrocytoma to glioblastoma Dysregulated autophagy is coupled to altered cholesterol metabolism in malignant gliomas TMZ-resistant glioblastoma cells undergo epithelial-to-mesenchymal transition and mitotic quiescence Resistant cells exhibit constrained bioenergetic capacity and mitochondrial remodeling Impaired autophagy suppresses de novo cholesterol synthesis and lipid recycling Lipidomics reveals accumulation of long-chain cholesteryl esters in TMZ-resistant cells Statin-based cholesterol inhibition fails to resensitize glioblastoma cells to temozolomide

cancer biology↗

bioRxiv2023

Early life exposure to cigarette smoke is associated with lung function changes and primes gene expression and DNA methylation changes at Cyp1a1 upon exposure later in life

Prenatal and early life exposure to cigarette smoke (CS) have repeatedly been shown to induce stable, long-term changes in DNA methylation (DNAm) in offspring. It has been hypothesized that these changes might be functionally related to the known outcomes of prenatal and early life CS exposure, which include impaired lung development, altered lung function and increased risk of asthma and wheeze. However, to date, few studies have examined DNAm changes induced by prenatal CS in tissues of the lung, and even fewer have attempted to examine the specific influences of prenatal versus early postnatal exposures. Here, we have established a mouse model of CS exposure which isolates the effects of prenatal and early postnatal CS exposures in early life. We have used this model to measure the effects of prenatal and/or postnatal CS exposures on lung function and immune cell infiltration as well as DNAm and expression of Cyp1a1, a candidate gene previously observed to demonstrate DNAm differences upon CS exposure in humans. Our study revealed that exposure to CS prenatally and in the early postnatal period cause long-lasting differences in offspring lung function, gene expression and lung Cyp1a1 DNAm, which wane over time but are reestablished upon re-exposure to CS in adulthood. This study creates a testable mouse model which can be used to investigate the effects of prenatal and early postnatal CS exposures and will contribute to the design of intervention strategies to mediate these detrimental effects.

genetics↗

bioRxiv2022

Tissue Specific Knockout of the Cardiolipin Transacylase Enzyme TAFAZZIN in Both Liver and Pancreatic Beta Cells Protects Mice From Diet-Induced Obesity

Mutations in the TAFAZZIN gene result in the X-linked genetic disease Barth Syndrome. The protein product tafazzin is a transacylase enzyme that remodels the phospholipid cardiolipin with fatty acids. Some Barth syndrome boys exhibit a lean phenotype. In addition, whole body knockdown of tafazzin in mice protects them from diet-induced obesity through increased hepatic fatty acid oxidation and reduced basal insulin secretion. We thus hypothesized that tafazzin deficiency in both the liver and beta cells of the pancreas contribute to this lean phenotype. Through a Cre-Lox approach we generated control, liver-specific, pancreatic beta cell-specific and liver and pancreatic beta cell-specific double knockout male mice. The animals were fed a high fat diet for 8 weeks and body weight, liver weight and fat pad weights determined. Liver-specific or pancreatic beta cell-specific male tafazzin knockout mice accumulated weight gain ({asymp}40% increase in body weight) at the same rate as control animals. In contrast, the liver- and beta cell-specific double tafazzin knockout mice exhibited a reduced rate of weight gain by 8 weeks ({asymp}26% increase in body weight) compared to control or the single tafazzin knockout animals. In addition, at 8 weeks the double tafazzin knockout mice exhibited reduced weight gain in tissues known to accumulate fat including the liver, the gonadal, inguinal and perirenal white adipose tissues and the brown adipose tissue. Thus, liver- and pancreatic beta cell-specific double tafazzin knockout male mice are protected from high fat diet induced weight gain and fat accumulation. These results may partially explain why some Barth Syndrome boys exhibit a lean phenotype.

biochemistry↗

bioRxiv2022

Differential Impact of Doxorubicin Dose on Cell Death and Autophagy Pathways during Acute Cardiotoxicity.

Doxorubicin (DOX) is an effective anthracycline used in chemotherapeutic regimens for a variety of haematological and solid tumors. However, its utility remains limited by its well-described, but poorly understood cardiotoxicity. Despite numerous studies describing various forms of regulated cell death and their involvement in DOX-mediated cardiotoxicity, the predominate form of cell death remains unclear. Part of this inconsistency lies in a lack of standardization of in vivo and in vitro model design. To this end, the objective of this study was to characterize acute low- and high-dose DOX exposure on cardiac structure and function in C57BL/6N mice, and evaluate regulated cell death pathways and autophagy both in vivo and in cardiomyocyte culture models. Acute low-dose DOX had little impact on cardiac structure or function; however, acute high-dose DOX elicited substantial cardiac necrosis resulting in diminished cardiac mass and volume, with a corresponding reduced cardiac output, and without impacting ejection fraction or fibrosis. Low-dose DOX consistently activated caspase-signaling with evidence of mitochondrial permeability transition. However, acute high-dose DOX had only modest impact on common necrotic signaling pathways, but instead led to an inhibition in autophagic flux. Intriguingly, when autophagy was inhibited in cultured cardiomyoblasts, DOX-induced necrosis was enhanced. Collectively, these observations implicate inhibition of autophagy flux as an important component of the acute necrotic response to DOX, but also suggest that acute high-dose DOX exposure does not recapitulate the disease phenotype observed in human cardiotoxicity.

physiology↗

bioRxiv2021

Altered Cardiolipin Metabolism is Associated with Cardiac Mitochondrial Dysfunction in Pulmonary Vascular Remodeled Perinatal Rat Pups

BackgroundPulmonary vascular remodeling (PVR) in utero results in the development of heart failure (HF). The alterations that occur in cardiac lipid and mitochondrial bioenergetics during the development of in utero PVR was unknown. MethodsPVR was induced in pups in utero by exposure of pregnant dams to indomethacin and hypoxia. Cardiac lipids, echocardiographic function and cardiomyocyte mitochondrial function were subsequently examined. ResultsPerinatal rat pups with PVR exhibited elevated left and right cardiac ventricular internal dimensions and reduced ejection fraction and fractional shortening compared to controls. Cardiac myocytes from these pups exhibited increased glycolytic capacity and glycolytic reserve compared to controls. However, respiration with glucose as substrate was unaltered. Fatty acid oxidation and ATP-insensitive respiration were increased in isolated cardiac myocytes from these pups compared to controls indicating mitochondrial dysfunction. Although abundance of mitochondrial respiratory complexes were unaltered, increased trilinoleoyl-lysocardiolipin levels in these pups was observed. A compensatory increase in both cardiolipin (CL) and phosphatidylethanolamine (PE) content were observed due to increased synthesis of these phospholipids. ConclusionAlterations in cardiac cardiolipin and phospholipid metabolism in PVR rat pups is associated with the mitochondrial bioenergetic and cardiac functional defects observed in their hearts. Impact statement- Phospholipid metabolism was examined in pulmonary vascular remodeling in perinatal rat pups. - Pulmonary vascular remodeling was induced in utero by treating pregnant dams with hypoxia and indomethacin at 19-21 days of gestation. - The offspring exhibited altered pulmonary arterial remodeling with subsequent cardiac hypertrophy, ventricular dysfunction, cardiac myocyte mitochondrial dysfunction with altered fatty acid utilization. - In addition, the offspring exhibited elevated cardiolipin, lysocardiolipin and phosphatidylethanolamine content which may potentially contribute to the cardiac mitochondrial dysfunction.

biochemistry↗

bioRxiv2020

Misoprostol Treatment Prevents Hypoxia-Induced Cardiac Dysfunction, Aberrant Cardiomyocyte Mitochondrial Dynamics and Permeability Transition Through Bnip3 Phosphorylation

Systemic hypoxia is a common element in most perinatal emergencies and is a known driver of Bnip3 expression in the neonatal heart. Bnip3 plays a prominent role in the evolution of necrotic cell death, disrupting ER calcium homeostasis and initiating mitochondrial permeability transition (MPT). Emerging evidence suggests a cardioprotective role for the prostaglandin E1 analogue misoprostol during periods of hypoxia, but the mechanisms for this protection are not completely understood. Using a combination of mouse and cell models, we tested if misoprostol is cardioprotective during neonatal hypoxic injury by altering Bnip3 function. Here we report that hypoxia elicits mitochondrial-fragmentation, MPT, reduced ejection fraction, and evidence of necroinflammation, which were abrogated with misoprostol treatment or Bnip3 knockout. Through molecular studies we show that misoprostol leads to PKA-dependent Bnip3 phosphorylation at threonine-181, and subsequent redistribution of Bnip3 from mitochondrial Opa1 and the ER through an interaction with 14-3-3 proteins. Taken together, our results demonstrate a role for Bnip3 phosphorylation in the regulation of cardiomyocyte contractile/metabolic dysfunction, and necroinflammation. Furthermore, we identify a potential pharmacological mechanism to prevent neonatal hypoxic injury.

cell biology↗

bioRxiv2020

Berberine alleviates adiposity and cardiac dysfunction in offspring exposed to gestational diabetes mellitus

The most robust risk factor for type 2 diabetes in childhood is prior exposure to diabetes during gestation. Currently, there are few evidence-based strategies to attenuate the of risk of metabolic syndrome in offspring exposed to gestational diabetes mellitus (GDM). Berberine (BBR) is an isoquinoline alkaloid extracted from Chinese herbs and exhibits glucose lowering properties. It has been used safely for centuries in humans. Our objective was to determine whether BBR treatment improves health outcomes in the mouse offspring of GDM dams. Dams were fed either a lean low-fat diet (Lean, LF,10% kcal fat) or a GDM-inducing high-fat/high sucrose diet (GDM, HF, 45% kcal fat) prior to breeding and throughout pregnancy. The resulting Lean and GDM-exposed offspring were randomly assigned a LF, HF or HF diet containing BBR (160 mg/kg/d) for 12 weeks. We determined that BBR treatment significantly reduced body weight ([~]20%), % body fat ([~]40%) and gonadal fat pad mass ([~]60%) compared to HF-fed GDM offspring. Furthermore, BBR treatment of HF-fed GDM offspring normalized insulin levels in the plasma and isolated pancreatic islets. Differences in food consumption did not contribute to altered body composition in BBR treated mice, as levels remained similar between experimental groups. Alternatively, BBR-treatment was associated with increased whole-body oxygen consumption (VO2), activity and heat production. Additionally, we determined that HF-fed GDM offspring developed a cardiomyopathy, characterized by increased isovolumetric contraction ([~]150%, IVCT), relaxation time ([~]70%, IVRT), elevated cardiac triglyceride ([~]120%) and reduced mitochondrial function (30%, spare capacity) compared to LF fed Lean controls. BBR treatment normalized heart function, reduced triglyceride levels and maintained mitochondrial function. Our data supports BBR as a potential pharmacotherapeutic approach to improve health outcomes in individuals exposed to GDM. Key Points SummaryO_LIGestational diabetes mellitus is a common metabolic complication of pregnancy which is increasing worldwide due to the prevalence of obesity. C_LIO_LIIt is known that individuals exposed to gestational diabetes have elevated risk of developing metabolic syndrome however there are few evidence-based strategies which provide protection. C_LIO_LIBerberine is a natural compound found in Chinese herbs which has been safely used for centuries to treat type 2 diabetes mellitus. C_LIO_LIWe determined that berberine treatment of offspring exposed to gestational diabetes attenuated weight gain, reduced insulin levels and normalized both heart and pancreatic function. C_LIO_LIOur data supports berberine as a potential pharmacotherapeutic approach to improve health outcomes in individuals exposed to gestational diabetes. C_LI

physiology↗

bioRxiv2019

Nix induced mitochondrial fission, mitophagy, and myocyte insulin resistance are abrogated by PKA phosphorylation.

Lipotoxicity is a form of cellular stress caused by the accumulation of lipids resulting in mitochondrial dysfunction and insulin resistance in muscle. Previously, we demonstrated that the mitophagy receptor Nix is responsive to lipotoxicity and accumulates in response to diacylglycerols induced by high-fat (HF) feeding. In addition, previous studies have implicated autophagy and mitophagy in muscle insulin sensitivity. To provide a better understanding of these observations, we undertook gene expression array and shot-gun metabolomics studies in soleus muscle from rodents on an HF diet. Interestingly, we observed a modest reduction in several autophagy-related genes including Beclin-1, ATG3, and -5. Moreover, we observed alterations in the fatty acyl composition of cardiolipins and phosphatidic acids. Given the previously reported roles of these phospholipids and Nix in mitochondrial dynamics, we investigated aberrant mitochondrial fission and turn-over as a mechanism of myocyte insulin resistance. In a series of gain-of-function and loss-of-function experiments in rodent and human myotubes, we demonstrate that Nix accumulation triggers mitochondrial depolarization, fragmentation, calcium-dependent activation of DRP1, and mitophagy. In addition, Nix-induced mitochondrial fission leads to myotube insulin resistance through activation of mTOR-p70S6 kinase inhibition of IRS1, which is contingent on phosphatidic acids and Rheb. Finally, we demonstrate that Nix-induced mitophagy and insulin resistance can be reversed by direct phosphorylation of Nix by PKA, leading to the translocation of Nix from the mitochondria and sarcoplasmic reticulum to the cytosol. These findings provide insight into the role of Nix-induced mitophagy and myocyte insulin resistance during an overfed state when overall autophagy-related gene expression is reduced. Furthermore, our data suggests a mechanism by which exercise or pharmacological activation of PKA may overcome myocyte insulin resistance. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=98 SRC="FIGDIR/small/825828v2_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@15d0a4org.highwire.dtl.DTLVardef@34f358org.highwire.dtl.DTLVardef@5427f3org.highwire.dtl.DTLVardef@10ae48a_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2019

Non-nutritive sweetener consumption during pregnancy affects adiposity in mouse and human offspring

Overweight and obesity affect over 20% of children worldwide. Emerging evidence shows that nonnutritive sweeteners (NNS) could adversely influence weight gain and metabolic health, particularly during critical periods of development. Thus, we aimed to investigate the impact of prenatal NNS exposure on postnatal growth and adiposity. Among 2298 families participating in the CHILD cohort study, children born to mothers who regularly consumed NNS during pregnancy had elevated body mass index and adiposity at 3 years of age. In a complementary study designed to eliminate confounding by human lifestyle factors and investigate causal mechanisms, we exposed pregnant mice and cultured adipocytes to NNS (aspartame or sucralose) at doses relevant to human consumption. In mice, maternal NNS exposure caused elevated body weight, adiposity and insulin resistance in offspring, especially in males. Further, in 3T3-L1 pre-adipocyte cells, sucralose exposure during early stages of differentiation caused increased lipid accumulation and expression of adipocyte differentiation genes (e.g. C/EBP-, FABP4, FAS). The same genes were upregulated in the adipose tissue of male mouse offspring born to sucralose-fed dams. Together, these clinical and experimental findings provide evidence suggesting that maternal NNS consumption induces obesity risk in the offspring through effects on adiposity and adipocyte differentiation.\n\nOne Sentence SummaryMaternal consumption of non-nutritive sweeteners during pregnancy stimulates adipocyte differentiation, insulin resistance, weight gain, and adiposity in mouse and human offspring.

developmental biology↗