Mariana Morales Quinones

University of Missouri Columbia, Biological Sciences, Graduate Student

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The field of autophagy has greatly expanded in the recent past, demonstrating that autophagy is critical for cell survival under a variety of stresses, including nutrient depletion, extreme environmental conditions and disease. There is a lot of interest in the mechanism of autophagosome formation and regulation, consequently while at graduate school I studied the protein-protein interactions and identified some of the factors that are important for autophagic transport.

At Dr. Stromhaug’s lab we utilized the Cytoplasm-to-vacuole targeting (Cvt) pathway in yeast. This is a type of selective autophagy that transports vacuolar proteases that are synthesized in cytosol, to the vacuole where they reside, using the autophagic machinery to package them into vesicles.

Morales Quinones, M., and Stromhaug, P.E. (2011). The propeptide of Aminopeptidase 1 mediates aggregation and vesicle formation in the Cytoplasm-to-vacuole targeting pathway. The Journal of biological chemistry. In press.

Morales Quinones, M., Long, K.A., and Stromhaug, P.E. (2012). The mechanism and regulation of autophagic receptor Atg19 binding to Ape1 aggregates during the Cytoplasm-to-vacuole targeting pathway in yeast. Submitted for publication.

We show that putative helical structures mediate binding between the cargo, Aminopeptidase 1 (Ape1), and the autophagic receptor Atg19. The same helical structure on Ape1 causes it to form aggregates in cytosol. Aggregation is critical for transport via the Cvt pathway, suggesting Ape1 aggregates function as a scaffold for recruitment of autophagic proteins and membrane, for vesicle formation. A new role for Atg1 and Atg13 in regulation of Atg19 localization to aggregates was also identified. Atg1 and Atg13 both play a role in autophagosome formation and interact with several Atg proteins, but their function is not well understood.

For these studies a novel in vitro assay was developed, which takes advantage of Ape1 aggregation to form large (over 0.5µm in diameter) Cvt complexes, and use these to study recruitment of autophagic proteins in a cell-free system. In addition, several molecular techniques were applied (expression cloning, gel electrophoresis, western blotting, immunoprecipitation, chromatography and differential centrifugation), as well as yeast two-hybrid screens and fluorescence microscopy.
Supervisors: Per E. Stromhaug

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Papers by Mariana Morales Quinones

Omental Arteries from Diabetic Hypertensive Subjects are Larger and Stiffer than those from Non‐Diabetic Normotensives

The FASEB Journal

LIM Kinase Inhibition Diminishes Hypertension and Vasoconstriction‐Induced Inward Remodeling in Mouse and Human Resistance Arteries

The FASEB Journal

LIMK (LIM Kinase) Inhibition Prevents Vasoconstriction- and Hypertension-Induced Arterial Stiffening and Remodeling

Supplemental Digital Content is available in the text. Increased arterial stiffness and vascular ... more Supplemental Digital Content is available in the text. Increased arterial stiffness and vascular remodeling precede and are consequences of hypertension. They also contribute to the development and progression of life-threatening cardiovascular diseases. Yet, there are currently no agents specifically aimed at preventing or treating arterial stiffening and remodeling. Previous research indicates that vascular smooth muscle actin polymerization participates in the initial stages of arterial stiffening and remodeling and that LIMK (LIM kinase) promotes F-actin formation and stabilization via cofilin phosphorylation and consequent inactivation. Herein, we hypothesize that LIMK inhibition is able to prevent vasoconstriction- and hypertension-associated arterial stiffening and inward remodeling. We found that small visceral arteries isolated from hypertensive subjects are stiffer and have greater cofilin phosphorylation than those from nonhypertensives. We also show that LIMK inhibition ...

Sodium glucose transporter 2 inhibition reduces arterial stiffness and improves endothelial function in a mouse model of aging

The FASEB Journal, 2021

Cystamine reduces vascular stiffness in Western diet-fed female mice

American Journal of Physiology-Heart and Circulatory Physiology

Consumption of diets high in fat, sugar and salt (Western diet, WD) is associated with accelerate... more Consumption of diets high in fat, sugar and salt (Western diet, WD) is associated with accelerated arterial stiffening, a major independent risk factor for cardiovascular disease (CVD). Obese women are more prone to develop arterial stiffening leading to more frequent and severe CVD compared to men. As tissue transglutaminase (TG2) has been implicated in vascular stiffening, our goal herein was to determine the efficacy of cystamine, a non-specific TG2 inhibitor, at reducing vascular stiffness in female mice chronically fed a WD. Three experimental groups of female mice were created. One was fed regular chow diet (CD) for 43 weeks starting at four weeks of age. The second was fed a WD for the same 43 weeks, whereas a third cohort was fed WD, but also received cystamine (216 mg/kg/d) in the drinking water during the last eight weeks on the diet (WD+C). All vascular stiffness parameters assessed, including aortic pulse wave velocity and the incremental modulus of elasticity of isolate...

Disruption of the smooth muscle actin cytoskeleton decreases human resistance artery stiffness and abolishes smooth muscle contractile function

Mutation of the 5' untranslated region stem-loop mRNA structure reduces type I collagen deposition and arterial stiffness in male obese mice

American journal of physiology. Heart and circulatory physiology, 2021

Arterial stiffening, a characteristic feature of obesity and type 2 diabetes, contributes to the ... more Arterial stiffening, a characteristic feature of obesity and type 2 diabetes, contributes to the development and progression of cardiovascular diseases (CVD). Currently, no effective prophylaxis or therapeutics is available to prevent or treat arterial stiffening. A better understanding of the molecular mechanisms underlying arterial stiffening is vital to identify newer targets and strategies to reduce CVD burden. A major contributor to arterial stiffening is increased collagen deposition. In the 5' untranslated regions of mRNAs encoding for type I collagen, an evolutionally conserved stem-loop (SL) structure plays an essential role in its stability and post-transcriptional regulation. Here, we show that feeding a high fat/high sucrose (HFHS) diet for 28 weeks increases adiposity, insulin resistance, and blood pressure in male wild-type littermates. Moreover, arterial stiffness, assessed in vivo via aortic pulse wave velocity, and ex vivo using atomic force microscopy in aortic...

Abstract P279: Glycocalyx Restoration Reduces Arterial Stiffness In Diabetic Female Mice

Hypertension

Arterial stiffening, a characteristic feature of type 2 diabetes, is an important contributor to ... more Arterial stiffening, a characteristic feature of type 2 diabetes, is an important contributor to the development and progression of cardiovascular disease (CVD). Thus, a better understanding of the precipitating factors underlying arterial stiffening is vital to identify newer targets and strategies to reduce CVD burden, particularly in diabetic women who exhibit heightened arterial stiffening and more severe CVD. Degradation of the endothelial glycocalyx in diabetes is thought to contribute to endothelial dysfunction and CVD development. However, whether glycocalyx degradation is also an important determinant of arterial stiffening remains unknown. Herein, we hypothesize that restoration of the glycocalyx with dietary supplementation of glycocalyx precursors (DSGP, including glucosamine sulfate, fucoidan, superoxide dismutase, and high molecular weight hyaluronan; Endocalyx TM ) improves endothelial function and lessens arterial stiffness in diabetic female mice. To test this hypot...

TRAF3IP2 (TRAF3 Interacting Protein 2) Mediates Obesity-Associated Vascular Insulin Resistance and Dysfunction in Male Mice

Hypertension

Insulin resistance in the vasculature is a characteristic feature of obesity and contributes to t... more Insulin resistance in the vasculature is a characteristic feature of obesity and contributes to the pathogenesis of vascular dysfunction and disease. However, the molecular mechanisms underlying obesity-associated vascular insulin resistance and dysfunction remain poorly understood. We hypothesized that TRAF3IP2 (TRAF3 interacting protein 2), a proinflammatory adaptor molecule known to activate pathological stress pathways and implicated in cardiovascular diseases, plays a causal role in obesity-associated vascular insulin resistance and dysfunction. We tested this hypothesis by employing genetic-manipulation in endothelial cells in vitro, in isolated arteries ex vivo, and diet-induced obesity in a mouse model of TRAF3IP2 ablation in vivo. We show that ectopic expression of TRAF3IP2 blunts insulin signaling in endothelial cells and diminishes endothelium-dependent vasorelaxation in isolated aortic rings. Further, 16 weeks of high fat/high sucrose feeding impaired glucose tolerance, ...

OR17-06 Transglutaminase 2 Inhibition Reduces Aortic Stiffness in Western Diet-Fed Female Mice

Journal of the Endocrine Society

Widespread consumption of diets high in fat, sugars and salt (Western diet, WD) is associated art... more Widespread consumption of diets high in fat, sugars and salt (Western diet, WD) is associated arterial stiffening, which is a major independent risk factor for cardiovascular disease (CVD). Notably, while WD feeding increases the risk of CVD in both males and females, the latter are more prone to develop arterial stiffening. However, the mechanisms underlying WD-induced arterial stiffening are poorly understood, particularly in females, and there are currently no specific treatments targeted at vascular stiffening.Tissue transglutaminase 2 (TG2) is an enzyme that mediates the cross-linking and stabilization of extracellular matrix proteins such as collagen, and promotes the polymerization of actin stress fibers of the cytoskeleton. It is ubiquitously expressed and abundantly present in the vasculature. Mounting evidence implicates TG2 activation in the pathogenesis of arterial stiffening and vascular fibrosis. Herein we propose that TG2 activation is central to WD-induced arterial s...

TRAF3IP2 ablation protects against obesity‐associated glycemic dysregulation, elevated blood pressure, and endothelial dysfunction

The FASEB Journal

Chronic Elevation of Endothelin-1 Alone May Not Be Sufficient to Impair Endothelium-Dependent Relaxation

Hypertension

Endothelin-1 (ET-1) is a powerful vasoconstrictor peptide considered to be causally implicated in... more Endothelin-1 (ET-1) is a powerful vasoconstrictor peptide considered to be causally implicated in hypertension and the development of cardiovascular disease. Increased ET-1 is commonly associated with reduced NO bioavailability and impaired vascular function; however, whether chronic elevation of ET-1 directly impairs endothelium-dependent relaxation (EDR) remains elusive. Herein, we report that (1) prolonged ET-1 exposure (ie, 48 hours) of naive mouse aortas or cultured endothelial cells did not impair EDR or reduce eNOS (endothelial NO synthase) activity, respectively ( P >0.05); (2) mice with endothelial cell–specific ET-1 overexpression did not exhibit impaired EDR or reduced eNOS activity ( P >0.05); (3) chronic (8 weeks) pharmacological blockade of ET-1 receptors in obese/hyperlipidemic mice did not improve aortic EDR or increase eNOS activity ( P >0.05); and (4) vascular and plasma ET-1 did not inversely correlate with EDR in resistance arteries isolated from human s...

Sexual dimorphism in obesity-associated endothelial ENaC activity and stiffening in mice

Endocrinology

Obesity and insulin resistance stiffen the vasculature with females appearing to be more adversel... more Obesity and insulin resistance stiffen the vasculature with females appearing to be more adversely affected. As augmented arterial stiffness is an independent predictor of cardiovascular disease (CVD), the increased predisposition of obese and insulin-resistant women to arterial stiffening may explain their heightened risk for CVD. However, the cellular mechanisms by which females are more vulnerable to arterial stiffening associated with obesity and insulin resistance remain largely unknown. Here we provide evidence that female mice are more susceptible to Western diet-induced endothelial cell stiffening compared to age-matched males. Mechanistically, we show that the increased stiffening of the vascular intima in Western diet-fed female mice is accompanied by enhanced epithelial sodium channel (ENaC) activity in endothelial cells (EnNaC). Our data further indicate that: 1) estrogen signaling through estrogen receptor alpha (ERα) increases EnNaC activity to a larger extent in femal...

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A unique way to form a vesicle: Aminopeptidase 1 aggregation and its binding to receptor Atg19 for recruitment of autophagic proteins to form a vesicle in the cytoplasm-to-vacuole-targeting pathway in yeast

First Name:Mariana Middle Name: Last Name:Morales Quinones Adviser's First Name:Per Adviser&#... more First Name:Mariana Middle Name: Last Name:Morales Quinones Adviser's First Name:Per Adviser's Last Name:Stromhaug Co-Adviser's First Name: Co-Adviser's Last Name: Graduation Term:FS 2011 Department:Biological Sciences Degree:PhD Title: A UNIQUE WAY TO FORM A VESICLE: AMINOPEPTIDASE 1 AGGREGATION AND ITS BINDING TO RECEPTOR ATG19 FOR RECRUITMENT OF AUTOPHAGIC PROTEINS TO FORM A VESICLE IN THE CYTOPLASM-TO-VACUOLE-TARGETING PATHWAY IN YEAST

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Propeptide of aminopeptidase 1 protein mediates aggregation and vesicle formation in cytoplasm-to-vacuole targeting pathway

The Journal of biological chemistry, Jan 23, 2012

Misfolded protein aggregation causes disease and aging; autophagy counteracts this by eliminating... more Misfolded protein aggregation causes disease and aging; autophagy counteracts this by eliminating damaged components, enabling cells to survive starvation. The cytoplasm-to-vacuole targeting pathway in yeast encompasses the aggregation of the premature form of aminopeptidase 1 (prApe1) in cytosol and its sequestration by autophagic proteins into a vesicle for vacuolar transport. We show that the propeptide of Ape1 is important for aggregation and vesicle formation and that it is sufficient for binding to prApe1 and Atg19. Defective aggregation disrupts vacuolar transport, suggesting that aggregate shape is important in vesicle formation, whereas Atg19 binding is not sufficient for vacuolar transport. Aggregation involves hydrophobicity, whereas Atg19 binding requires additional electrostatic interactions. Ape1 dodecamerization may cluster propeptides into trimeric structures, with sufficient affinity to form propeptide hexamers by binding to other dodecamers, causing aggregation. We...

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The propeptide of Aminopeptidase 1 mediates aggregation and vesicle formation in the Cytoplasm-to-vacuole targeting pathway.

Misfolded protein aggregation causes disease and ageing; autophagy counteracts this by eliminatin... more Misfolded protein aggregation causes disease and ageing; autophagy counteracts this by eliminating damaged components, enabling cells to survive starvation. The Cytoplasm-to-vacuole-targeting (Cvt) pathway in yeast encompasses the aggregation of the premature form of Aminopeptidase 1 (prApe1) in cytosol, and its sequestration by autophagic proteins into a vesicle for vacuolar transport. We show that the propeptide of Ape1 is important for aggregation and vesicle formation, it is sufficient for binding to prApe1 and Atg19. Defective aggregation disrupts vacuolar transport, suggesting aggregate shape is important in vesicle formation, while Atg19 binding is not sufficient for vacuolar transport. Aggregation involves hydrophobicity, while Atg19 binding requires additional electrostatic interactions. Ape1 dodecamerization may cluster propeptides into trimeric structures, with sufficient affinity to form propeptide hexamers by binding to other dodecamers, causing aggregation. We show that Ape1 aggregates bind Atg19 and Atg8 in vitro, this could be used as a scaffold for an in vitro assay of autophagosome formation to elucidate the mechanisms of autophagy.

Omental Arteries from Diabetic Hypertensive Subjects are Larger and Stiffer than those from Non‐Diabetic Normotensives

The FASEB Journal

LIM Kinase Inhibition Diminishes Hypertension and Vasoconstriction‐Induced Inward Remodeling in Mouse and Human Resistance Arteries

The FASEB Journal

LIMK (LIM Kinase) Inhibition Prevents Vasoconstriction- and Hypertension-Induced Arterial Stiffening and Remodeling