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1.
Mol Cell Biochem ; 429(1-2): 1-10, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28083716

RESUMEN

Blood and tissue levels of manganese (Mn) are lower in type 2 diabetic and atherosclerosis patients compared with healthy subjects. Adiponectin has anti-diabetic and anti-atherogenic properties. Impairment in Disulfide bond A-like protein (DsbA-L) is associated with low adiponectin levels and diabetes. This study investigates the hypothesis that the beneficial effects of Mn supplementation are mediated by adiponectin and DsbA-L. At 6 weeks of age, Male Zucker diabetic fatty rats (ZDF) were randomly divided into two groups: diabetic controls and Mn-supplemented diabetic rats. Each rat was supplemented with Mn (D+Mn, 16 mg/kg BW) or water (placebo, D+P) daily for 7 weeks by oral gavage. For cell culture studies, Human Umbilical Vein Endothelial Cells (HUVEC) or 3T3L1 adipocytes were pretreated with Mn (0-10 µM MnCl2) for 24 h, followed by high glucose (HG, 25 mM) or normal glucose (5 mM) exposure for another 24 h. Mn supplementation resulted in higher adiponectin (p = 0.01), and lower ICAM-1 (p = 0.04) and lower creatinine (p = 0.04) blood levels compared to those in control ZDF rats. Mn-supplemented rats also caused reduced oxidative stress (ROS) and NADPH oxidase, and higher DsbA-L expression in the liver (p = 0.03) of ZDF rats compared to those in livers of control rats; however, Fe levels in liver were lower but not significant (p = 0.08). Similarly, treatment with high glucose (25 mM) caused a decrease in DsbA-L, which was prevented by Mn supplementation in HUVEC and adipocytes. Mechanistic studies with DsbA-L siRNA showed that the beneficial effects of Mn supplementation on ROS, NOX4, and ICAM-1 expression were abolished in DsbA-L knock-down HUVEC. These studies demonstrate that DsbA-L-linked adiponectin mediates the beneficial effects observed with Mn supplementation and provides evidence for a novel mechanism by which Mn supplementation can increase adiponectin and reduce the biomarkers of endothelial dysfunction in diabetes.


Asunto(s)
Adiponectina/metabolismo , Creatinina/sangre , Diabetes Mellitus Experimental/dietoterapia , Glutatión Transferasa/metabolismo , Molécula 1 de Adhesión Intercelular/metabolismo , Manganeso/administración & dosificación , Células 3T3-L1 , Animales , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/dietoterapia , Diabetes Mellitus Tipo 2/metabolismo , Suplementos Dietéticos , Regulación hacia Abajo , Células Endoteliales/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana , Humanos , Masculino , Manganeso/farmacología , Ratones , Estrés Oxidativo/efectos de los fármacos , Ratas , Ratas Zucker , Regulación hacia Arriba
2.
J Appl Toxicol ; 37(2): 222-230, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27241723

RESUMEN

A recombinant vaccine composed of a fusion protein formulated with aluminum hydroxide adjuvant is under development for protection against diseases caused by Streptococcus pyogenes. The safety and local reactogenicity of the vaccine was assessed by a comprehensive series of clinical, pathologic and immunologic tests in preclinical experiments. Outbred mice received three intramuscular injections of 1/5th of the human dose (0.1 ml) and rabbits received two injections of the full human dose. Control groups received adjuvant or protein antigen. The vaccine did not cause clinical evidence of systemic toxicity in mice or rabbits. There was a transient increase of peripheral blood neutrophils after the third vaccination of mice. In addition, the concentration of acute phase proteins serum amyloid A and haptoglobin was significantly increased 1 day after injection of the vaccine in mice. There was mild transient swelling and erythema of the injection site in both mice and rabbits. Treatment-related pathology was limited to inflammation at the injection site and accumulation of adjuvant-containing macrophages in the draining lymph nodes. In conclusion, the absence of clinical toxicity in two animal species suggest that the vaccine is safe for use in a phase I human clinical trial. Copyright © 2016 John Wiley & Sons, Ltd.


Asunto(s)
Adyuvantes Inmunológicos/efectos adversos , Hidróxido de Aluminio/efectos adversos , Proteínas Bacterianas/inmunología , Exotoxinas/inmunología , Vacunas Estreptocócicas/efectos adversos , Streptococcus pyogenes/inmunología , Adyuvantes Inmunológicos/administración & dosificación , Hidróxido de Aluminio/administración & dosificación , Hidróxido de Aluminio/inmunología , Animales , Anticuerpos Antibacterianos/sangre , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Femenino , Reacción en el Punto de Inyección , Masculino , Ratones Endogámicos , Conejos , Proteínas Recombinantes de Fusión , Vacunas Estreptocócicas/administración & dosificación , Vacunas Estreptocócicas/inmunología
3.
J Biol Chem ; 288(9): 6409-16, 2013 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-23329836

RESUMEN

Endothelial dysfunction is a hallmark of increased vascular inflammation, dyslipidemia, and the development of atherosclerosis in diabetes. Previous studies have reported lower levels of Mn(2+) in the plasma and lymphocytes of diabetic patients and in the heart and aortic tissue of patients with atherosclerosis. This study examines the hypothesis that Mn(2+) supplementation can reduce the markers/risk factors of endothelial dysfunction in type 2 diabetes. Human umbilical vein endothelial cells (HUVECs) were cultured with or without Mn(2+) supplementation and then exposed to high glucose (HG, 25 mm) to mimic diabetic conditions. Mn(2+) supplementation caused a reduction in monocyte adhesion to HUVECs treated with HG or MCP-1. Mn(2+) also inhibited ROS levels, MCP-1 secretion, and ICAM-1 up-regulation in HUVECs treated with HG. Silencing studies using siRNA against MnSOD showed that similar results were observed in MnSOD knockdown HUVECs following Mn(2+) supplementation, suggesting that the effect of manganese on monocyte adhesion to endothelial cells is mediated by ROS and ICAM-1, but not MnSOD. To validate the relevance of our findings in vivo, Zucker diabetic fatty rats were gavaged daily with water (placebo) or MnCl2 (16 mg/kg of body weight) for 7 weeks. When compared with placebo, Mn(2+)-supplemented rats showed lower blood levels of ICAM-1 (17%, p < 0.04), cholesterol (25%, p < 0.05), and MCP-1 (28%, p = 0.25). These in vitro and in vivo studies demonstrate that Mn(2+) supplementation can down-regulate ICAM-1 expression and ROS independently of MnSOD, leading to a decrease in monocyte adhesion to endothelial cells, and therefore can lower the risk of endothelial dysfunction in diabetes.


Asunto(s)
Glucosa/farmacología , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Manganeso/farmacología , Monocitos/metabolismo , Edulcorantes/farmacología , Animales , Adhesión Celular/efectos de los fármacos , Quimiocina CCL2/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Células Endoteliales de la Vena Umbilical Humana/patología , Humanos , Molécula 1 de Adhesión Intercelular/biosíntesis , Molécula 1 de Adhesión Intercelular/genética , Monocitos/patología , Ratas , Ratas Zucker , Especies Reactivas de Oxígeno/metabolismo , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo
4.
Vaccines (Basel) ; 12(10)2024 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-39460254

RESUMEN

While approved vaccines for COVID-19 provide protection against severe disease and death, they have limited efficacy in the prevention of infection and virus transmission. Mucosal immunity is preferred over systemic immunity to provide protection at the point of entry against pathogens such as SARS-CoV-2. VaxForm has developed an oral vaccine delivery platform that elicits mucosal and systemic immune responses by targeting immune cells in the gut through C-type lectin receptors. The technology consists of microencapsulating the vaccine with an enteric polymer, which also results in enhanced thermostability. This article describes the formulation development and in vivo testing of a novel protein-based oral COVID-19 vaccine using this technology. Results demonstrate successful induction of immune response in mice and showed that the particle size of the vaccines following administration can impact the ratio of mucosal to systemic response. Immunogenicity and thermostability of liquid suspension and dry powder versions of the vaccine were compared in mice. The liquid suspension vaccine showed excellent heat resistance by maintaining immunogenicity after 14 days of storage at 60 °C. While further investigation is needed to determine correlates of protection and duration of response for mucosal immunity, this study demonstrates the vaccine's potential as a COVID-19 booster to enhance mucosal protection in humans and improve global access by lowering the cost of production, removing cold-chain requirements, and allowing self-administration.

5.
Vaccines (Basel) ; 11(9)2023 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-37766180

RESUMEN

Group A streptococcus (GAS) is a global pathogen associated with significant morbidity and mortality for which there is currently no licensed vaccine. Vaccine development has been slow, mostly due to safety concerns regarding streptococcal antigens associated with autoimmunity and related complications. For a GAS vaccine to be safe, it must be ensured that the antigens used in the vaccine do not elicit an antibody response that can cross-react with host tissues. In this study, we evaluated the safety of our GAS vaccine candidate called VaxiStrep in New Zealand White rabbits. VaxiStrep is a recombinant fusion protein comprised of streptococcal pyrogenic exotoxin A (SpeA) and exotoxin B (SpeB), also known as erythrogenic toxins, adsorbed to an aluminum adjuvant. The vaccine elicited a robust immune response against the two toxins in the rabbits without any adverse events or toxicity. No signs of autoimmune pathology were detected in the rabbits' brains, hearts, and kidneys via immunohistochemistry, and serum antibodies did not cross-react with cardiac or neuronal tissue proteins associated with rheumatic heart disease or Sydenham chorea (SC). This study further confirms that VaxiStrep does not elicit autoantibodies and is safe to be tested in a first-in-human trial.

6.
J Biol Chem ; 286(23): 20267-74, 2011 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-21515692

RESUMEN

Stationary-phase Saccharomyces cerevisiae cells transferred from spent rich media into water live for weeks, whereas the same cells die within hours if transferred into water with 2% glucose in a process called sugar-induced cell death (SICD). Our hypothesis is that SICD is due to a dysregulated Crabtree effect, which is the phenomenon whereby glucose transiently inhibits respiration and ATP synthesis. We found that stationary-phase cells in glucose/water consume 21 times more O(2) per cell than exponential-phase cells in rich media, and such excessive O(2) consumption causes reactive oxygen species to accumulate. We also found that inorganic phosphate and succinate protect against SICD but by different mechanisms. Phosphate protects by triggering the synthesis of Fru-1,6-P(2), which inhibits respiration in isolated mitochondria. Succinate protects in wild-type cells but fails to protect in dic1Δ cells. DIC1 codes for a mitochondrial inner membrane protein that exchanges cytosolic succinate for matrix phosphate. We propose that succinate depletes matrix phosphate, which in turn inhibits respiration and ATP synthesis. In sum, restoring the Crabtree effect, whether with phosphate or succinate, protects cells from SICD.


Asunto(s)
Adenosina Trifosfato/biosíntesis , Glucosa/metabolismo , Consumo de Oxígeno/fisiología , Fosfatos/metabolismo , Saccharomyces cerevisiae/metabolismo , Ácido Succínico/metabolismo , Adenosina Trifosfato/genética , Fructosadifosfatos/genética , Fructosadifosfatos/metabolismo , Saccharomyces cerevisiae/genética
7.
Biochem Biophys Res Commun ; 414(1): 205-8, 2011 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-21946065

RESUMEN

The Prestwick and NIH chemical libraries were screened for drugs that protect baker's yeast from sugar-induced cell death (SICD). SICD is triggered when stationary-phase yeast cells are transferred from spent rich medium into water with 2% glucose and no other nutrients. The rapid, apoptotic cell death occurs because reactive oxygen species (ROS) accumulate. We found that triclabendazole, which is used to treat liver flukes in cattle and man, partially protects against SICD. Characterization of triclabendazole revealed that it also protects yeast cells from death induced by the Parkinson's disease-related protein alpha-synuclein (α-syn), which is known to induce the accumulation of ROS.


Asunto(s)
Bencimidazoles/farmacología , Fármacos Neuroprotectores/farmacología , Estrés Oxidativo/efectos de los fármacos , Saccharomyces cerevisiae/efectos de los fármacos , Animales , Bencimidazoles/aislamiento & purificación , Bovinos , Línea Celular , Humanos , Fármacos Neuroprotectores/aislamiento & purificación , Especies Reactivas de Oxígeno/metabolismo , Bibliotecas de Moléculas Pequeñas , Triclabendazol , alfa-Sinucleína/farmacología
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