Biology subjects

Fazzari, M.

Publications and source records attributed to Fazzari, M..

4 recordsLinked to original sources

bioRxiv2026

A Regionally Inspired West Virginia Obesogenic Diet Induces Fat Accretion and Metabolic Dysfunction While Identifying Sex Disparity

Obesity prevalence continues to rise in the United States, with a disproportionate burden falling to West Virginia. To investigate the metabolic effects of region-specific dietary patterns, we developed the West Virginia Obesogenic Diet (WV-OD), a compositionally defined rodent diet based on nutritional analyses of meals consumed by obese individuals in the state. The WV-OD closely mirrors the macronutrient profile of the average American diet while incorporating regional features such as a greater sodium level and significantly less fiber. We compared the metabolic effects of the WV-OD to a matched control diet (WV-CD) and to a widely used high-fat diet (HFD, 60% of calories derived from fat) in male and female C57BL/6J mice. After 19 weeks, WV-OD-fed males exhibited weight gain and adiposity comparable to HFD-fed counterparts, along with glucose intolerance and hepatic triglyceride accumulation confirming the obesogenic and metabolically disruptive properties of the WV-OD. Unlike HFD-fed mice, WV-OD-fed males also displayed elevated circulating cholesterol and cholesterol esters without corresponding increases in hepatic total cholesterol. When compared to the HFD, the WV-OD did not increase uric acid or xanthine oxidoreductase (XOR) content of liver or circulation; however, both males and females on the WV-OD demonstrated trends towards elevated plasma uric acid. Interestingly, while exhibiting a similar caloric intake on either diet, the WV-OD females did not demonstrate significant fat accretion or metabolic dysfunction compared to females subjected to the 60% HFD. In toto, these findings: 1) establish the WV-OD as a regionally-grounded, yet broadly representative tool for modeling diet-induced obesity and metabolic dysfunction, 2) offer a physiologically relevant alternative to extreme-fat dietary models in preclinical research and 3) highlight sex-based differences in response to diet-induced obesity.

physiology↗

bioRxiv2024

15-Lipoxygenase-Mediated Lipid Peroxidation Regulates LRRK2 Kinase Activity

Mutations in leucine-rich repeat kinase 2 (LRRK2) that increase its kinase activity are strongly linked to genetic forms of Parkinsons disease (PD). However, the regulation of endogenous wild-type (WT) LRRK2 kinase activity remains poorly understood, despite its frequent elevation in idiopathic PD (iPD) patients. Various stressors such as mitochondrial dysfunction, lysosomal dyshomeostasis, or vesicle trafficking deficits can activate WT LRRK2 kinase, but the specific molecular mechanisms are not fully understood. We found that the production of 4-hydroxynonenal (4-HNE), a lipid hydroperoxidation end-product, is a common biochemical response to these diverse stimuli. 4-HNE forms post-translational adducts with Cys2024 and Cys2025 in the kinase activation loop of WT LRRK2, significantly increasing its kinase activity. Additionally, we discovered that the 4-HNE responsible for regulating LRRK2 is generated by the action of 15-lipoxygenase (15-LO), making 15-LO an upstream regulator of the pathogenic hyperactivation of LRRK2 kinase activity. Pharmacological inhibition or genetic ablation of 15-LO prevents 4-HNE post-translational modification of LRRK2 kinase and its subsequent pathogenic hyperactivation. Therefore, 15-LO inhibitors, or methods to lower 4-HNE levels, or the targeting of Cys2024/2025 could provide new therapeutic strategies to modulate LRRK2 kinase activity and treat PD.

neuroscience↗

bioRxiv2021

Cooperation between CYB5R3 and NOX4 via coenzyme Q mitigates endothelial inflammation

NADPH oxidase 4 (NOX4) regulates endothelial inflammation by producing reactive oxygen species. Since coenzyme Q (CoQ) mimics affect NOX4 activity, we hypothesize that cytochrome b5 reductase 3 (CYB5R3), a CoQ reductase abundant in vascular endothelial cells, modulates inflammatory activation. Mice lacking endothelial CYB5R3 (R3 KO), under lipopolysaccharides (LPS) challenge, showed exacerbated hypotension, decreased acetylcholine-induced vasodilation, and elevated vascular adhesion molecule 1 (Vcam-1) mRNA in aorta. In vitro, silencing Cyb5r3 enhanced LPS-induced VCAM-1 protein in a NOX4 dependent manner. APEX2- based electron microscopy and proximity biotinylation demonstrated CYB5R3s localization on the mitochondrial outer membrane and its interaction with NOX4, which was further confirmed by the proximity ligation assay. Notably, Cyb5r3 silenced HAECs had less total H2O2 but more mitochondrial O2*-. Using inactive or non-membrane bound active CYB5R3, we found CYB5R3 activity and membrane translocation were needed for optimal generation of H2O2 by NOX4. Lastly, CoQ deficient cells showed decreased NOX4-derived H2O2, indicating a requirement for endogenous CoQ in NOX4 activity. In conclusion, CYB5R3 mitigates endothelial inflammatory activation by assisting in NOX4-dependent H2O2 generation via CoQ. NOVELTY AND SIGNIFICANCEO_ST_ABSWhat Is Known?C_ST_ABSNADPH oxidase 4 (NOX4) reportedly produces primarily hydrogen peroxide (H2O2) and, to a lesser extent, superoxide (O2*-) and has been shown to have both beneficial and deleterious effects in the cardiovascular system. NOX4 activity can be affected by NAD(P)H quinone oxidoreductase 1 (NQO1), a CoQ reductase, and synthetic quinone compounds used to mimic CoQ. Cytochrome b5 reductase 3 (CYB5R3) is known to reduce CoQ and is highly expressed in endothelial cells. What New Information Does This Article Contribute?In vivo, the lack of endothelial CYB5R3 causes exacerbated lipopolysaccharides (LPS)-induced inflammatory signaling, endothelial dysfunction, and hypotension. Endothelial CYB5R3 mitigates inflammatory signaling by LPS and tumor necrosis factor (TNF-) in a NOX4 dependent manner. In endothelial cells, CYB5R3 and NOX4 reside in close proximity on the mitochondrial outer membrane. NOX4s ability to generate H2O2 depends on the membrane translocation and activity of CYB5R3 and the presence of endogenous CoQ. NONSTANDARD Abbreviations and Acronyms [Table 1] Protein names are abbreviated as capital letters (e.g., CYB5R3), while the corresponding gene names are annotated as in italic lower cases (e.g., Cyb5r3).

cell biology↗

bioRxiv2021

Neuronal NADPH oxidase in Parkinson disease pathogenesis

Mitochondrial dysfunction and oxidative stress are strongly implicated in the pathogenesis of Parkinsons disease (PD) and there is evidence that mitochondrially-generated superoxide can activate NADPH oxidase 2 (NOX2), which is a major enzymatic generator of superoxide. Although NOX2 has been examined in the context of PD, previous studies have focused on microglial function; the role of neuronal NOX2 in PD pathogenesis remains to be defined. Here we devised and validated a proximity ligation assay for NOX2 activity and demonstrated that in human PD and 2 models thereof, neuronal NOX2 is highly active in substantia nigra dopamine neurons. Further, NOX2 activity is responsible for accumulation, post-translational modification and oligomerization of -synuclein as well as activation of leucine-rich repeat kinase 2 (LRRK2). Administration of a brain-penetrant, specific NOX2 inhibitor prevented NOX2 activation and its downstream effects in vivo in a rat model of PD. We conclude that neuronal NOX2 is a major contributor to oxidative stress in PD, to -synuclein pathology and to LRRK2 activation in idiopathic PD. In this context, NOX2 inhibitors hold potential as a disease-modifying therapy in PD. SummaryIn dopamine neuron, NADPH oxidase isoform 2 amplifies the oxidative stress-related pathogenic cascade in Parkinsons disease

neuroscience↗