María Isabel Hernández‐Álvarez

Centro de Investigación Biomédica en Red Diabetes y Enfermedades Metabólicas Asociadas

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

António Zorzano

Universitat de Barcelona

Manuel Palacı́n

Universitat de Barcelona

David Sebastián

Universitat de Barcelona

Juan Pablo Muñoz

Hospital Sant Joan de Déu Barcelona

Raúl Ventura

Institut de Biomedicina de la Universitat de Barcelona

Sara C. Kozma

University of Cincinnati

Sónia R. Veiga

SIRIS Academic

Xuemei Ge

Chinese Academy of Medical Sciences & Peking Union Medical College

Saška Ivanova

Institute for Research in Biomedicine

Carol A. Mercer

University of Cincinnati

Cooperative Institutions

Universitat de Barcelona

Instituto de Salud Carlos III

Institute for Research in Biomedicine

Centro de Investigación Biomédica en Red

Centro de Investigación Biomédica en Red Diabetes y Enfermedades Metabólicas Asociadas

Institut d'Investigació Sanitària Pere Virgili

Universidad Rovira i Virgili

Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas

Institut d'Investigació Biomédica de Bellvitge

Universitat Autònoma de Barcelona

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Phenformin-Induced Mitochondrial Dysfunction Sensitizes Hepatocellular Carcinoma for Dual Inhibition of mTOR

Clinical Cancer Research (2018)

Sónia R. Veiga Xuemei Ge Carol A. Mercer María Isabel Hernández‐Álvarez Hala Elnakat Thomas

Abstract Purpose: Hepatocellular carcinoma (HCC) ranks second in cancer mortality and has limited therapeutic options. We recently described the synergistic effect of allosteric and ATP-site competitive inhibitors against the mTOR for the treatment of HCC. However, such inhibitors induce hyperglycemia and increase mitochondrial efficiency. Here we determined whether the mitochondrial complex I inhibitor phenformin could reverse both side effects, impose an energetic stress on cancer cells, and suppress the growth of HCC. Experimental Design: Human HCC cell lines were used in vitro to access the signaling and energetic impact of mTOR inhibitors and phenformin, either alone or in combination. Next, the therapeutic utility of these drugs alone or in combination was investigated preclinically in human orthotopic tumors implanted in mice, by analyzing their impact on the tumor burden and overall survival. Results: We found phenformin caused mitochondrial dysfunction and fragmentation, inducing a compensatory shift to glycolysis. In contrast, dual inhibition of mTOR impaired cell growth and glycolysis, while increasing mitochondrial fusion and efficiency. In a mouse model of human HCC, dual inhibition of mTOR, together with phenformin, was highly efficacious in controlling tumor burden. However, more strikingly, pretreatment with phenformin sensitized tumors to dual inhibition of mTOR, leading to a dramatic improvement in survival. Conclusions: Treatment of HCC cells in vitro with the biguanide phenformin causes a metabolic shift to glycolysis, mitochondrial dysfunction and fragmentation, and dramatically sensitizes orthotopic liver tumors to dual inhibition of mTOR. We therefore propose this therapeutic approach should be tested clinically in HCC. Clin Cancer Res; 24(15); 3767–80. ©2018 AACR.

Phenformin

Biguanide

Liver Cancer

10.1158/1078-0432.ccr-18-0177

Cite

Citations (36)

Decreased expression of mitochondrial aminoacyl-tRNA synthetases causes downregulation of mitochondrial OXPHOS subunits in type 2 diabetic skeletal muscle

medRxiv (Cold Spring Harbor Laboratory) (2022)

Iliana López‐Soldado Adrian Gabriel Torres Raúl Ventura Inma Martínez-Ruíz Angels Díaz-Ramos

Abstract Type 2 diabetes mellitus (T2D) affects millions of people worldwide and is one of the leading causes of morbidity and mortality. The skeletal muscle (SKM) is the most important tissue involved in maintaining glucose homeostasis and substrate oxidation, and it undergoes insulin resistance in T2D. In this study, we identify the existence of alterations in the expression of mitochondrial aminoacyl-tRNA synthetases (mt-aaRSs) in skeletal muscle from two different forms of T2D: early-onset type 2 diabetes (YT2) (onset of the disease before 30 years of age) and the classical form of the disease (OT2). GSEA analysis from microarray studies revealed the repression of mitochondrial mt-aaRSs independently of age, which was validated by real-time PCR assays. In agreement with this, a reduced expression of several encoding mt-aaRSs was also detected in skeletal muscle from diabetic (db/db) mice but not in obese ob/ob mice. In addition, the expression of the mt-aaRSs proteins most relevant in the synthesis of mitochondrial proteins, threonyl-tRNA, and leucyl-tRNA synthetases (LARS2 and TARS2) were also repressed in muscle from db/db mice. It is likely that these alterations participate in the reduced expression of proteins synthesized in the mitochondria detected in db/db mice. Because it is known that, nitrosative stress inhibits aminoacylation of TARS2 and LARS2 activities, we noticed an increased protein expression of iNOS in isolated muscle mitochondria in diabetic mice. Our results indicate a reduced expression of mitochondrial mt-aaRSs in skeletal muscle from T2D patients, which may participate in the reduced expression of proteins synthesized in mitochondria. This may be due to an enhanced NO production secondary to enhanced iNOS expression in muscle under diabetic conditions. Highlights Mt-aaRSs are downregulated in the skeletal muscle of type 2 diabetic patients and diabetic mice. The downregulation of mt-aaRSs in the skeletal muscle of diabetic mice is affecting the synthesis of ND2 which is a mitochondrially encoded subunit of complex I. Mitochondrial iNOS could be a target for reduced expression of mt-aaRSs in the skeletal muscle of diabetic mice.

Amino Acyl-tRNA Synthetases

10.1101/2022.12.30.22283970

Cite

Citations (1)

Endoplasmic Reticulum Isolation: An Optimized Approach into Cells and Mouse Liver Fractionation

BIO-PROTOCOL (2023)

Marc Leiro Raúl Ventura Nil Rojo-Querol María Isabel Hernández‐Álvarez

The subfractionation of the endoplasmic reticulum (ER) is a widely used technique in cell biology. However, current protocols present limitations such as low yield, the use of large number of dishes, and contamination with other organelles. Here, we describe an improved method for ER subfractionation that solves other reported methods' main limitations of being time consuming and requiring less starting material. Our protocol involves a combination of different centrifugations and special buffer incubations as well as a fine-tuned method for homogenization followed by western blotting to confirm the purity of the fractions. This protocol contains a method to extract clean ER samples from cells using only five (150 mm) dishes instead of over 50 plates needed in other protocols. In addition, in this article we not only propose a new cell fractionation approach but also an optimized method to isolate pure ER fractions from one mouse liver instead of three, which are commonly used in other protocols. The protocols described here are optimized for time efficiency and designed for seamless execution in any laboratory, eliminating the need for special/patented reagents. Key features • Subcellular fractionation from cells and mouse liver. • Uses only five dishes (150 mm) or one mouse liver to extract highly enriched endoplasmic reticulum without mitochondrial-associated membrane contamination. • These protocols require the use of ultracentrifuges, dounce homogenizers, and/or Teflon Potter Elvehjem. As a result, highly enriched/clean samples are obtained. Graphical overview.

Cell fractionation

Organelle

Homogenization

10.21769/bioprotoc.4803

Cite

Citations (0)

The mitochondrial negative regulator MCJ is a therapeutic target for acetaminophen-induced liver injury

Nature Communications (2017)

Lucía Barbier‐Torres Paula Iruzubieta David Fernández–Ramos Teresa C. Delgado Daniel Taibo

Acetaminophen (APAP) is the active component of many medications used to treat pain and fever worldwide. Its overuse provokes liver injury and it is the second most common cause of liver failure. Mitochondrial dysfunction contributes to APAP-induced liver injury but the mechanism by which APAP causes hepatocyte toxicity is not completely understood. Therefore, we lack efficient therapeutic strategies to treat this pathology. Here we show that APAP interferes with the formation of mitochondrial respiratory supercomplexes via the mitochondrial negative regulator MCJ, and leads to decreased production of ATP and increased generation of ROS. In vivo treatment with an inhibitor of MCJ expression protects liver from acetaminophen-induced liver injury at a time when N-acetylcysteine, the standard therapy, has no efficacy. We also show elevated levels of MCJ in the liver of patients with acetaminophen overdose. We suggest that MCJ may represent a therapeutic target to prevent and rescue liver injury caused by acetaminophen.

Acetaminophen

10.1038/s41467-017-01970-x

Cite

Citations (95)

Decreased expression of mitochondrial aminoacyl-tRNA synthetases causes downregulation of OXPHOS subunits in type 2 diabetic muscle

Redox Biology (2023)

Iliana López‐Soldado Adrian Gabriel Torres Raúl Ventura Inma Martínez-Ruíz Angels Díaz‐Ramos

Type 2 diabetes mellitus (T2D) affects millions of people worldwide and is one of the leading causes of morbidity and mortality. The skeletal muscle (SKM) is one of the most important tissues involved in maintaining glucose homeostasis and substrate oxidation, and it undergoes insulin resistance in T2D. In this study, we identify the existence of alterations in the expression of mitochondrial aminoacyl-tRNA synthetases (mt-aaRSs) in skeletal muscle from two different forms of T2D: early-onset type 2 diabetes (YT2) (onset of the disease before 30 years of age) and the classical form of the disease (OT2). GSEA analysis from microarray studies revealed the repression of mitochondrial mt-aaRSs independently of age, which was validated by real-time PCR assays. In agreement with this, a reduced expression of several encoding mt-aaRSs was also detected in skeletal muscle from diabetic (db/db) mice but not in obese ob/ob mice. In addition, the expression of the mt-aaRSs proteins most relevant in the synthesis of mitochondrial proteins, threonyl-tRNA, and leucyl-tRNA synthetases (TARS2 and LARS2) were also repressed in muscle from db/db mice. It is likely that these alterations participate in the reduced expression of proteins synthesized in the mitochondria detected in db/db mice. We also document an increased iNOS abundance in mitochondrial-enriched muscle fractions from diabetic mice that may inhibit aminoacylation of TARS2 and LARS2 by nitrosative stress. Our results indicate a reduced expression of mt-aaRSs in skeletal muscle from T2D patients, which may participate in the reduced expression of proteins synthesized in mitochondria. An enhanced mitochondrial iNOS could play a regulatory role in diabetes.

Amino Acyl-tRNA Synthetases

10.1016/j.redox.2023.102630

Cite

Citations (6)

The NADPH oxidase NOX4 regulates lipid metabolism, which contributes to its tumour suppressor actions in hepatocellular carcinoma

Journal of Hepatology (2020)

Irene Peñuelas‐Haro Esther Bertrán Eva Crosas‐Molist Fulvio Santacatterina Silvia Marín

NOX4

10.1016/s0168-8278(20)30708-x

Cite

Citations (0)

Deficient Endoplasmic Reticulum-Mitochondrial Phosphatidylserine Transfer Causes Liver Disease

Cell (2019)

María Isabel Hernández‐Álvarez David Sebastián Sara Vives Saška Ivanova Paola Bartoccioni

MFN2

Steatohepatitis

Steatosis

Phospholipid transfer protein

Phosphatidylethanolamine

10.1016/j.cell.2019.04.010

Cite

Citations (283)

D816V mutation induces mitochondrial morphologic and functional changes through BNIP3 downregulation in human myeloid cell lines ROSA and TF-1.

Experimental Hematology (2025)

Sabina Cisa‐Wieczorek María Isabel Hernández‐Álvarez Matilde Parreño J. Edgar Díaz Muñoz Elena Bussaglia

10.1016/j.exphem.2025.104748

Cite

Citations (0)

Phenformin-induced mitochondrial dysfunction sensitizes hepatocellular carcinoma for dual inhibition of mTOR

Annals of Oncology (2018)

Sonia Pereira Da Veiga Xuemei Ge Carol A. Mercer María Isabel Hernández‐Álvarez Howard Thomas

Introduction: Hepatocellular carcinoma (HCC) ranks second in cancer mortality and has limited therapeutic options. We recently described the synergistic effect of allosteric and ATP-site competitive inhibitors against the mammalian target of rapamycin (mTOR) for the treatment of HCC. However, such inhibitors induce glycemia and increase mitochondrial efficiency. Here we determined whether the mitochondrial complex I inhibitor Phenformin could reverse both side effects, impose an energetic-stress on cancer cells and suppress HCC growth. Methods: Human HCC cell lines were used in vitro to access the signaling and energetic impact of mTOR inhibitors and Phenformin, either alone or in combination. Next, the therapeutic utility of these drugs alone or in combination was investigated pre-clinically in human orthotopic tumors implanted in mice, by analyzing their impact on the tumor burden and overall survival. Results: We found Phenformin caused mitochondrial dysfunction and fragmentation, inducing a compensatory shift to glycolysis. In contrast, dual inhibition of mTOR impaired cell growth and glycolysis, while increasing mitochondrial fusion and efficiency. In a mouse model of human HCC, dual inhibition of mTOR, together with Phenformin, was highly efficacious in controlling tumor burden. However, more striking, pretreatment with Phenformin sensitized tumors to dual inhibition of mTOR, leading to a dramatic improvement in survival. Conclusion: Treatment of HCC cells in vitro with the biguanide Phenformin causes a metabolic shift to glycolysis, mitochondrial dysfunction and fragmentation, and dramatically sensitizes orthotopic liver tumors to dual inhibition of mTOR. We therefore propose this therapeutic approach should be tested clinically in HCC.

Phenformin

Biguanide

10.1093/annonc/mdy151.323

Cite

Citations (2)

Subjects With Early-Onset Type 2 Diabetes Show Defective Activation of the Skeletal Muscle PGC-1α/Mitofusin-2 Regulatory Pathway in Response to Physical Activity

Diabetes Care (2009)

María Isabel Hernández‐Álvarez Hood Thabit Nicole Burns Syed Muhammad Ismail Shah Imad Brema

OBJECTIVE Type 2 diabetes is associated with insulin resistance and skeletal muscle mitochondrial dysfunction. We have found that subjects with early-onset type 2 diabetes show incapacity to increase Vo2max in response to chronic exercise. This suggests a defect in muscle mitochondrial response to exercise. Here, we have explored the nature of the mechanisms involved. RESEARCH DESIGN AND METHODS Muscle biopsies were collected from young type 2 diabetic subjects and obese control subjects before and after acute or chronic exercise protocols, and the expression of genes and/or proteins relevant to mitochondrial function was measured. In particular, the regulatory pathway peroxisome proliferator–activated receptor γ coactivator (PGC)-1α/mitofusin-2 (Mfn2) was analyzed. RESULTS At baseline, subjects with diabetes showed reduced expression (by 26%) of the mitochondrial fusion protein Mfn2 and a 39% reduction of the α-subunit of ATP synthase. Porin expression was unchanged, consistent with normal mitochondrial mass. Chronic exercise led to a 2.8-fold increase in Mfn2, as well as increases in porin, and the α-subunit of ATP synthase in muscle from control subjects. However, Mfn2 was unchanged after chronic exercise in individuals with diabetes, whereas porin and α-subunit of ATP synthase were increased. Acute exercise caused a fourfold increase in PGC-1α expression in muscle from control subjects but not in subjects with diabetes. CONCLUSIONS Our results demonstrate alterations in the regulatory pathway that controls PGC-1α expression and induction of Mfn2 in muscle from patients with early-onset type 2 diabetes. Patients with early-onset type 2 diabetes display abnormalities in the exercise-dependent pathway that regulates the expression of PGC-1α and Mfn2.

MFN2

10.2337/dc09-1305

Cite

Citations (177)