Mitochondrial E3 ubiquitin ligase 1 (MUL1) as a novel therapeutic target for diseases associated with mitochondrial dysfunction.

Mitochondrial E3 ubiquitin ligase 1 (MUL1) is a mitochondrial outer membrane-anchored protein-containing transmembrane domain in its N- and C-terminal regions, where both are exposed to the cytosol. Interestingly the C-terminal region has a RING finger domain responsible for its E3 ligase activity, as ubiquitin or in SUMOylation, interacting with proteins related to mitochondrial fusion and fission, cell survival, and tumor suppressor process, such as Akt. Therefore, MUL1 is involved in various cellular processes, such as mitochondrial dynamics, inter-organelle communication, proliferation, mitophagy, immune response, inflammation and cell apoptosis. MUL1 is expressed at a higher basal level in the heart, immune system organs, and blood. Here, we discuss the role of MUL1 in mitochondrial dynamics and its function in various pathological models, both in vitro and in vivo. In this context, we describe the role of MUL1 in: (1) the inflammatory response, by regulating NF-κB activity; (2) cancer, by promoting cell death and regulating exonuclear function of proteins, such as p53; (3) neurological diseases, by maintaining communication with other organelles and interacting with proteins to eliminate damaged organelles and; (4) cardiovascular diseases, by maintaining mitochondrial fusion/fission homeostasis. In this review, we summarize the latest advances in the physiological and pathological functions of MUL1. We also describe the different substrates of MUL1, acting as a positive or negative regulator in various pathologies associated with mitochondrial dysfunction. In conclusion, MUL1 could be a potential key target for the development of therapies that focus on ensuring the functionality of the mitochondrial network and, furthermore, the quality control of intracellular components by synchronously modulating the activity of different cellular mechanisms involved in the aforementioned pathologies. This, in turn, will guide the development of targeted therapies.

Polycystin-1 regulates cardiomyocyte mitophagy.

Polycystin-1 (PC1) is a transmembrane protein found in different cell types, including cardiomyocytes. Alterations in PC1 expression have been linked to mitochondrial damage in renal tubule cells and in patients with autosomal dominant polycystic kidney disease. However, to date, the regulatory role of PC1 in cardiomyocyte mitochondria is not well understood. The analysis of mitochondrial morphology from cardiomyocytes of heterozygous PC1 mice (PDK1+/- ) using transmission electron microscopy showed that cardiomyocyte mitochondria were smaller with increased mitochondria density and circularity. These parameters were consistent with mitochondrial fission. We knocked-down PC1 in cultured rat cardiomyocytes and human-induced pluripotent stem cells (iPSC)-derived cardiomyocytes to evaluate mitochondrial function and morphology. The results showed that downregulation of PC1 expression results in reduced protein levels of sub-units of the OXPHOS complexes and less functional mitochondria (reduction of mitochondrial membrane potential, mitochondrial respiration, and ATP production). This mitochondrial dysfunction activates the elimination of defective mitochondria by mitophagy, assessed by an increase of autophagosome adapter protein LC3B and the recruitment of the Parkin protein to the mitochondria. siRNA-mediated PC1 knockdown leads to a loss of the connectivity of the mitochondrial network and a greater number of mitochondria per cell, but of smaller sizes, which characterizes mitochondrial fission. PC1 silencing also deregulates the AKT-FoxO1 signaling pathway, which is involved in the regulation of mitochondrial metabolism, mitochondrial morphology, and processes that are part of cell quality control, such as mitophagy. Together, these data provide new insights about the controls that PC1 exerts on mitochondrial morphology and function in cultured cardiomyocytes dependent on the AKT-FoxO1 signaling pathway.

Pro-fibrotic effect of oxidized LDL in cardiac myofibroblasts.

Inflammatory signals associated with cardiac diseases trigger trans-differentiation of cardiac fibroblasts to cardiac myofibroblasts. Cardiac myofibroblasts are the main cell type involved in the development of cardiac fibrosis, a diffuse and disproportionate accumulation of collagen in the myocardium. Although the role of the scavenger like-lectin receptor LOX-1 was previously investigated in cardiac fibroblasts and fibrosis, the involvement of the LOX-1 ligand -oxidized low-density lipoprotein (oxLDL)- on cardiac myofibroblast function still remains unexplored. In the present work, we investigated the effect of oxLDL/LOX-1 on fibrotic markers and cardiac myofibroblast function. Our in vitro results showed that oxLDL increased cardiac myofibroblast proliferation, triggered an increase in the synthesis of collagen type I and fibronectin containing extra domain A, and stimulated collagen type I secretion. oxLDL also decreased cardiac myofibroblast migration, collagen gel contraction and cell area, without modifying α-smooth muscle actin protein levels. These effects were dependent on LOX-1, because LOX-1 knockdown abolished oxLDL effects. Collectively these data showed that oxLDL has important modulatory effects on cardiac myofibroblast function.

The ECHO model proved to be a useful tool to increase clinicians' self-effectiveness for care of patients with Hepatitis C in Argentina.

The ECHO model was developed to expand access to medical care for populations with HCV infection in underserved areas. We aimed to compare HCV treatment outcomes in community-based clinics with the Austral University Hospital (AUH) and to assess improvement in physician knowledge and skills. In October 2015, we established an HCV ECHO clinic at the AUH in Buenos Aires. To evaluate the impact of this programme, we conducted a prospective cohort study comparing treatment for HCV infection at the AUH with healthcare providers from different Argentinean provinces. A survey evaluating skills and competence in HCV care was administered, and results were compared. The primary endpoint was sustained virologic response (SVR) and under direct-acting antivirals. Since the implementation of ECHO clinics, a total of 25 physicians participated in at least one session (median 10.0; IQR 3.0-18.0). SVR rates (n = 437 patients) were 94.2% (95% CI 90.4-96.8) in patients treated at AUH clinic (n = 227/242) and 96.4% (95% CI 92.7-98.5) in those treated at ECHO sites (n = 188/195), with a nonsignificant difference between sites, 2.2% SVR difference (95% CI -0.24-0.06; P = 0.4). We also found a significant improvement in all the evaluated skills and abilities. Replicating the ECHO model helped to improve participants' skills in the management of HCV achieving similar SVR rates. ECHO model was demonstrated to be an effective intervention able to multiply and expand HCV treatment, a critical barrier to access to care that needs to be solved if we are committed with WHO goals to eliminate HCV by 2030.

GDF-11 prevents cardiomyocyte hypertrophy by maintaining the sarcoplasmic reticulum-mitochondria communication.

Growth differentiation factor 11 (GDF11) is a novel factor with controversial effects on cardiac hypertrophy both in vivo and in vitro. Although recent evidence has corroborated that GDF11 prevents the development of cardiac hypertrophy, its molecular mechanism remains unclear. In our previous work, we showed that norepinephrine (NE), a physiological pro-hypertrophic agent, increases cytoplasmic Ca2+ levels accompanied by a loss of physical and functional communication between sarcoplasmic reticulum (SR) and mitochondria, with a subsequent reduction in the mitochondrial Ca2+ uptake and mitochondrial metabolism. In order to study the anti-hypertrophic mechanism of GDF11, our aim was to investigate whether GDF11 prevents the loss of SR-mitochondria communication triggered by NE. Our results show that: a) GDF11 prevents hypertrophy in cultured neonatal rat ventricular myocytes treated with NE. b) GDF11 attenuates the NE-induced loss of contact sites between both organelles. c) GDF11 increases oxidative mitochondrial metabolism by stimulating mitochondrial Ca2+ uptake. In conclusion, the GDF11-dependent maintenance of physical and functional communication between SR and mitochondria is critical to allow Ca2+ transfer between both organelles and energy metabolism in the cardiomyocyte and to avoid the activation of Ca2+-dependent pro-hypertrophic signaling pathways.

From biomass-derived fructose to γ-valerolactone: Process design and techno-economic assessment.

This work proposes a process design and techno-economic assessment for the production of γ-valerolactone from lignocellulosic derived fructose at industrial scale, with the aim of exploring its feasibility, identifying potential obstacles, and suggesting improvements in the context of France. First, the conceptual process design is developed, the process modelled and optimized. Second, different potential scenarios for the energy supply to the process are analyzed by means of a set of economic key performance indicators, aimed at highlighting the best potential profitability scenario for the sustainable exploitation of waste biomass in the context analyzed. The lowest Minimum Selling Price for GVL is obtained at 10 kt/y plant fueled by biomass, i.e. 1.89 €/kg, along with the highest end-of-live revenue, i.e. 113 M€. Finally, a sensitivity and uncertainties analysis, based on Monte Carlo simulations, are carried out on the results in order to test their robustness with respect to key input parameters.

Winds of change a tale of: asthma and microbiome.

The role of the microbiome in asthma is highlighted, considering its influence on immune responses and its connection to alterations in asthmatic patients. In this context, we review the variables influencing asthma phenotypes from a microbiome perspective and provide insights into the microbiome's role in asthma pathogenesis. Previous cohort studies in patients with asthma have shown that the presence of genera such as Bifidobacterium, Lactobacillus, Faecalibacterium, and Bacteroides in the gut microbiome has been associated with protection against the disease. While, the presence of other genera such as Haemophilus, Streptococcus, Staphylococcus, and Moraxella in the respiratory microbiome has been implicated in asthma pathogenesis, indicating a potential link between microbial dysbiosis and the development of asthma. Furthermore, respiratory infections have been demonstrated to impact the composition of the upper respiratory tract microbiota, increasing susceptibility to bacterial diseases and potentially triggering asthma exacerbations. By understanding the interplay between the microbiome and asthma, valuable insights into disease mechanisms can be gained, potentially leading to the development of novel therapeutic approaches.

Prevalence of Obesity and Metabolic Syndrome in the High Cardiovascular Risk Setting of Rural Western Honduras.

Objective: To determine the prevalence of obesity and metabolic syndrome (MS) in the population older than 45 years in rural Western Honduras and contribute to the limited literature on MS in Central America. Methods: Descriptive cross-sectional study conducted in the District of Copan. The study includes 382 men and women aged 45 to 75 years. With proper consent, anthropometric parameters, blood pressure, blood sugar, and lipid profile were evaluated. MS was diagnosed by using the National Cholesterol Education Program Criteria - Adult Panel Treatment III (NCEP-ATP III). Data were stored in REDCap (Research Electronic Data Capture) and analyzed with STATA14. Results: Data were collected on 382 patients; of these, 38% were male and 62% female. The prevalence of obesity was 24.1% for both sexes. The prevalence of MS was 64.9%. Prevalence in males and females was 54% and 71%, respectively. Notable parameters were elevated triglycerides (71%), low High-density lipoprotein cholesterol (HDL-C) (63.4%), and abdominal obesity (56.8%). In men, the distribution of MS was more homogeneous, with a mean result of 80% amongst all ages. Conclusions: The overall prevalence of obesity and MS is severely underestimated in rural Honduras. The most remarkable parameter for MS was high triglycerides (71%). Sixty-nine percent of the population has above-normal Body Mass Index (BMI). Public health efforts to control comorbidities and tackle risk factors in this population should take utmost priority.

VCAM-1 as a predictor biomarker in cardiovascular disease.

The vascular cellular adhesion molecule-1 (VCAM-1) is a protein that canonically participates in the adhesion and transmigration of leukocytes to the interstitium during inflammation. VCAM-1 expression, together with soluble VCAM-1 (sVCAM-1) induced by the shedding of VCAM-1 by metalloproteinases, have been proposed as biomarkers in immunological diseases, cancer, autoimmune myocarditis, and as predictors of mortality and morbidity in patients with chronic heart failure (HF), endothelial injury in patients with coronary artery disease, and arrhythmias. This revision aims to discuss the role of sVCAM-1 as a biomarker to predict the occurrence, development, and preservation of cardiovascular disease.

Polycystin-1 is required for insulin-like growth factor 1-induced cardiomyocyte hypertrophy.

Cardiac hypertrophy is the result of responses to various physiological or pathological stimuli. Recently, we showed that polycystin-1 participates in cardiomyocyte hypertrophy elicited by pressure overload and mechanical stress. Interestingly, polycystin-1 knockdown does not affect phenylephrine-induced cardiomyocyte hypertrophy, suggesting that the effects of polycystin-1 are stimulus-dependent. In this study, we aimed to identify the role of polycystin-1 in insulin-like growth factor-1 (IGF-1) signaling in cardiomyocytes. Polycystin-1 knockdown completely blunted IGF-1-induced cardiomyocyte hypertrophy. We then investigated the molecular mechanism underlying this result. We found that polycystin-1 silencing impaired the activation of the IGF-1 receptor, Akt, and ERK1/2 elicited by IGF-1. Remarkably, IGF-1-induced IGF-1 receptor, Akt, and ERK1/2 phosphorylations were restored when protein tyrosine phosphatase 1B was inhibited, suggesting that polycystin-1 knockdown deregulates this phosphatase in cardiomyocytes. Moreover, protein tyrosine phosphatase 1B inhibition also restored IGF-1-dependent cardiomyocyte hypertrophy in polycystin-1-deficient cells. Our findings provide the first evidence that polycystin-1 regulates IGF-1-induced cardiomyocyte hypertrophy through a mechanism involving protein tyrosine phosphatase 1B.

Techno-economic and environmental sustainability of biomass waste conversion based on thermocatalytic reforming.

The development and design of innovative biomass waste to energy conversion processes is a key issue to pursue the implementation of circular economy and to endorse a sustainable management of agricultural land. Assessing the environmental and economic sustainability of such processes is of paramount importance to prevent the trade-off of their impacts. The present study focused on a novel biomass waste to energy conversion process based on thermocatalytic reforming (TCR). Two different agricultural waste substrates (olive wood pruning and digestate) were selected as reference cases for conversion to energy and valuable material fractions. Mass and energy balances allowed the calculation of environmental and economic indexes considering alternative scenarios for the final use of the energy and of the products obtained from the TCR conversion (i.e. syngas, bio-oil and bio-char). A sensitivity analysis was carried out to assess the robustness of results. The overall performances of the TCR process resulted strongly related to the characteristics of the biomass waste and to the possible use of the product fractions obtained in the TCR process. The use of bio-char for soil amendment, allowed by the high quality of bio-char obtained from the TCR, was a key point to improve the expected environmental and economic sustainability of the conversion process.

The Calcineurin A homologue from Trypanosoma cruzi lacks two important regulatory domains.

A novel protein from the parasite Trypanosoma cruzi homologous to calcineurin (serine-threonine phosphatase 2B) was identified and characterized. The Calcineurin A gene is present as a single copy gene per haploid genome and encodes a protein of 43 kDa that is expressed in all major developmental stages of T. cruzi. Surprisingly, it is mainly localized in the cell nucleus, in sharp contrast with its mammalian counterpart. The T. cruzi calcineurin A protein presents the three invariants motifs characteristic of the PPP serine-threonine phosphatase superfamily. However, out of the four domains typically present in all calcineurin described to date, the T. cruzi calcineurin A possess only two domains: the catalytic and the calcineurin B binding domain. Sequence similarity searches in the T. cruzi, Trypanosoma brucei and Leishmania major genomes revealed that only L. major presents a gene encoding a putative protein containing the four domains. On the other hand, the T. cruzi Calcineurin B subunit showed a conserved structure, and a reasonable level of similarity over the entire length with calcineurin B proteins from other organisms. Interaction between Calcineurin A and Calcineurin B was analyzed by yeast Two-Hybrid and GST pull-down assays.