Drug screening in human physiologic medium identifies uric acid as an inhibitor of rigosertib efficacy.

The non-physiological nutrient levels found in traditional culture media have been shown to affect numerous aspects of cancer cell physiology, including how cells respond to certain therapeutic agents. Here, we comprehensively evaluated how physiological nutrient levels impact therapeutic response by performing drug screening in human plasma-like medium (HPLM). We observed dramatic nutrient-dependent changes in sensitivity to a variety of FDA-approved and clinically trialed compounds including rigosertib, an experimental cancer therapeutic that has recently failed in phase 3 clinical trials. Mechanistically, we found that the ability of rigosertib to destabilize microtubules is strongly inhibited by the purine metabolism end product uric acid, which is uniquely abundant in humans relative to traditional in vitro and in vivo cancer models. These results demonstrate the broad and dramatic effects nutrient levels can have on drug response, and how incorporation of human-specific physiological nutrient media might help to identify compounds whose efficacy could be impacted in humans.

Drug screening in human physiologic medium identifies uric acid as an inhibitor of rigosertib efficacy.

The non-physiological nutrient levels found in traditional culture media have been shown to affect numerous aspects of cancer cell physiology, including how cells respond to certain therapeutic agents. Here, we comprehensively evaluated how physiological nutrient levels impact therapeutic response by performing drug screening in human plasma-like medium (HPLM). We observed dramatic nutrient-dependent changes in sensitivity to a variety of FDA-approved and clinically trialed compounds, including rigosertib, an experimental cancer therapeutic that has recently failed in phase 3 clinical trials. Mechanistically, we found that the ability of rigosertib to destabilize microtubules is strongly inhibited by the purine metabolism waste product uric acid, which is uniquely abundant in humans relative to traditional in vitro and in vivo cancer models. Structural modelling studies suggest that uric acid interacts with the tubulin-rigosertib complex and may act as an uncompetitive inhibitor of rigosertib. These results offer a possible explanation for the failure of rigosertib in clinical trials and demonstrate the utility of physiological media to achieve in vitro results that better represent human therapeutic responses.

Increased peripartum mortality associated with maternal subclinical malaria in Mozambique.

BACKGROUND: Plasmodium falciparum infection in pregnant women in sub-Saharan Africa is often asymptomatic. As these forms of malaria are often submicroscopic and difficult to diagnose by conventional methods (microscopy and/or rapid diagnostic test), diagnosis requires the use of molecular techniques such as polymerase chain reaction (PCR). This study analyses the prevalence of subclinical malaria and its association with adverse maternal and neonatal outcomes, a topic that has been scarcely evaluated in the literature. METHODS: A cross-sectional study was conducted using semi-nested multiplex PCR to assess the presence of P. falciparum in placental and peripheral blood of 232 parturient pregnant women at the Hospital Provincial de Tete, Mozambique between March 2017 and May 2019. Multivariate regressions were performed to assess the associations of maternal subclinical malaria with several maternal and neonatal outcomes after controlling for the presence of preeclampsia/eclampsia (PE/E) and HIV infection, as well as for other maternal and pregnancy characteristics. RESULTS: In total, 17.2% (n = 40) of the women studied had positive PCR for P. falciparum (7 in placental blood only, 3 in peripheral blood only). We found a significant association between subclinical malaria and a higher peripartum mortality risk, which persisted after controlling for maternal comorbidity and maternal and pregnancy characteristics (adjusted odds ratio: 3.50 [1.11-10.97]). In addition, PE/E and HIV infections were also significantly associated with several adverse maternal and neonatal outcomes. CONCLUSION: This study demonstrated the association of subclinical malaria, as well as of PE/E and HIV, in pregnant women with adverse maternal and neonatal outcomes. Therefore, molecular methods may be sensitive tools to identify asymptomatic infections that can reduce the impact on peripartum mortality and their contribution to sustained transmission of the parasite in endemic countries.

Regulation of neuronal energy metabolism by calcium: Role of MCU and Aralar/malate-aspartate shuttle.

Calcium is a major regulator of cellular metabolism. Calcium controls mitochondrial respiration, and calcium signaling is used to meet cellular energetic demands through energy production in the organelle. Although it has been widely assumed that Ca2+-actions require its uptake by mitochondrial calcium uniporter (MCU), alternative pathways modulated by cytosolic Ca2+ have been recently proposed. Recent findings have indicated a role for cytosolic Ca2+ signals acting on mitochondrial NADH shuttles in the control of cellular metabolism in neurons using glucose as fuel. It has been demonstrated that AGC1/Aralar, the component of the malate/aspartate shuttle (MAS) regulated by cytosolic Ca2+, participates in the maintenance of basal respiration exerted through Ca2+-fluxes between ER and mitochondria, whereas mitochondrial Ca2+-uptake by MCU does not contribute. Aralar/MAS pathway, activated by small cytosolic Ca2+ signals, provides in fact substrates, redox equivalents and pyruvate, fueling respiration. Upon activation and increases in workload, neurons upregulate OxPhos, cytosolic pyruvate production and glycolysis, together with glucose uptake, in a Ca2+-dependent way, and part of this upregulation is via Ca2+ signaling. Both MCU and Aralar/MAS contribute to OxPhos upregulation, Aralar/MAS playing a major role, especially at small and submaximal workloads. Ca2+ activation of Aralar/MAS, by increasing cytosolic NAD+/NADH provides Ca2+-dependent increases in glycolysis and cytosolic pyruvate production priming respiration as a feed-forward mechanism in response to workload. Thus, except for glucose uptake, these processes are dependent on Aralar/MAS, whereas MCU is the relevant target for Ca2+ signaling when MAS is bypassed, by using pyruvate or ß-hydroxybutyrate as substrates.

Safety and efficacy of methylprednisolone versus dexamethasone in critically ill patients with COVID-19 acute respiratory distress syndrome: a retrospective study.

Background: Corticosteroids (CSs), specifically dexamethasone (DEX), are the treatment of choice for severe acute respiratory distress syndrome (ARDS) due to COVID-19 pneumonia (CARDS). However, data from both ARDS and relatively small CARDS clinical trials have suggested improved outcomes with methylprednisolone (MP) versus DEX. The objective of this retrospective cohort study was to compare the safety and effectiveness of MP and DEX in critically ill CARDS patients. Methods: The study cohort included CARDS patients admitted to a tertiary referral intensive care unit (ICU) between April and September 2020 who received at least 5 days of CSs for CARDS. Results: The cohort was notable for a high severity of illness (overall, 88.5% of patients required mechanical ventilation and 16% required vasopressors on admission). The DEX group (n = 62) was significantly older with a higher illness severity [Sequential Organ Failure Assessment (SOFA) 6 (4.75-8) versus 4.5 (3-7), p = 0.008], while the MP group (n = 51) received significantly more loading doses [19 (37.3%) versus 4 (6.5%), p < 0.0001]. MP was associated with a shorter time to intubation and more rapid progression to mortality [days to death: 18 (15-23) versus 27 (15-34), p = 0.026]. After correction for baseline imbalances in age and SOFA score, DEX was associated with improved mortality at 90 days compared with MP [hazard ratio (HR) = 0.43, 95% confidence interval (CI) = 0.23-0.80, p = 0.008]. However, there were no differences between rates of secondary infections during hospitalization or insulin requirements at 7 and 14 days. Conclusion: In this cohort of critically ill CARDS, choice of CS was associated with mortality but not adverse event profile, and thus warrants further investigation.

A Common Variant at the 3'untranslated Region of the CCL7 Gene (rs17735770) Is Associated With Decreased Susceptibility to Coronary Heart Disease.

Monocytes participate in the development of atherosclerosis through the action of cytokines and other inflammatory mediators. Among them, CCR2 and its ligands, CCL2 and CCL7 play an important role, so the main objective of this work was to determine whether genetic variants affecting their activity were associated with cardiovascular disease. A cohort of 519 patients that have suffered coronary events was analyzed under a propensity score-matching protocol selecting a homogeneous set of cases and controls, according to age, sex, smoking status, dyslipidemia, arterial hypertension and type 2 diabetes as risk factors. While dyslipidemia and arterial hypertension were more prevalent among patients with angina pectoris, current smoking status and elevated inflammatory markers, including total leukocyte and monocyte counts, were more likely associated with acute coronary events. Propensity score matching analysis, performed to eliminate the influence of these risk factors and highlight genetic modifiers, revealed that a single nucleotide variant, rs17735770 at the 3'untranslated region of the CCL7 gene transcript, was associated with decreased cardiovascular risk in a group represented mostly by men, with an average age of 57, and without significant differences in traditional risk factors. Furthermore, the presence of this variant altered the local mRNA structure encompassing a binding site for miR-23ab, resulting in increased translation of a reporter gene in a miR23 independent fashion. The rs17735770 genetic variant led to increased expression of CCL7, a potential antagonist of CCR2 at inflammatory sites, where it could play a meaningful role during the evolution of atherosclerosis.

A Ca2+-Dependent Mechanism Boosting Glycolysis and OXPHOS by Activating Aralar-Malate-Aspartate Shuttle, upon Neuronal Stimulation.

Calcium is an important second messenger regulating a bioenergetic response to the workloads triggered by neuronal activation. In embryonic mouse cortical neurons using glucose as only fuel, activation by NMDA elicits a strong workload (ATP demand)-dependent on Na+ and Ca2+ entry, and stimulates glucose uptake, glycolysis, pyruvate and lactate production, and oxidative phosphorylation (OXPHOS) in a Ca2+-dependent way. We find that Ca2+ upregulation of glycolysis, pyruvate levels, and respiration, but not glucose uptake, all depend on Aralar/AGC1/Slc25a12, the mitochondrial aspartate-glutamate carrier, component of the malate-aspartate shuttle (MAS). MAS activation increases glycolysis, pyruvate production, and respiration, a process inhibited in the presence of BAPTA-AM, suggesting that the Ca2+ binding motifs in Aralar may be involved in the activation. Mitochondrial calcium uniporter (MCU) silencing had no effect, indicating that none of these processes required MCU-dependent mitochondrial Ca2+ uptake. The neuronal respiratory response to carbachol was also dependent on Aralar, but not on MCU. We find that mouse cortical neurons are endowed with a constitutive ER-to-mitochondria Ca2+ flow maintaining basal cell bioenergetics in which ryanodine receptors, RyR2, rather than InsP3R, are responsible for Ca2+ release, and in which MCU does not participate. The results reveal that, in neurons using glucose, MCU does not participate in OXPHOS regulation under basal or stimulated conditions, while Aralar-MAS appears as the major Ca2+-dependent pathway tuning simultaneously glycolysis and OXPHOS to neuronal activation.SIGNIFICANCE STATEMENT Neuronal activation increases cell workload to restore ion gradients altered by activation. Ca2+ is involved in matching increased workload with ATP production, but the mechanisms are still unknown. We find that glycolysis, pyruvate production, and neuronal respiration are stimulated on neuronal activation in a Ca2+-dependent way, independently of effects of Ca2+ as workload inducer. Mitochondrial calcium uniporter (MCU) does not play a relevant role in Ca2+ stimulated pyruvate production and oxygen consumption as both are unchanged in MCU silenced neurons. However, Ca2+ stimulation is blunt in the absence of Aralar, a Ca2+-binding mitochondrial carrier component of Malate-Aspartate Shuttle (MAS). The results suggest that Ca2+-regulated Aralar-MAS activation upregulates glycolysis and pyruvate production, which fuels mitochondrial respiration, through regulation of cytosolic NAD+/NADH ratio.

Wilson Disease Prevalence: Discrepancy Between Clinical Records, Registries and Mutation Carrier Frequency.

OBJECTIVES: Diagnosis of Wilson disease (WD) is difficult and, as early detection may prevent all symptoms, it is essential to know the exact prevalence to evaluate the cost-efficacy of a screening program. As the number of WD patients was high in our population, we wished to estimate prevalence by determining the carrier frequency for clinically relevant ATP7B mutations. METHODS: To estimate prevalence, screening for the most prevalent mutation was performed in 1661 individuals with ancestry in Gran Canaria, and the frequency of other mutations was estimated from patient records. Alternatively, ATP7B mutations were detected from exomes and genomes from 851 individuals with Canarian ancestry, 236 from Gran Canaria, and a public Spanish exome database. RESULTS: Estimated carrier frequencies in Gran Canaria ranged from 1 in 20 to 28, depending on the method used, resulting in prevalences of 1 case per 1547 to 3140 inhabitants. Alternatively, the estimated affected frequencies were 1 in 5985 to 7980 and 1 in 6278 to 16,510 in the archipelago or mainland Spain respectively. CONCLUSIONS: The number of carriers predicts much higher prevalences than reported, suggesting that WD is underdiagnosed; specific mutations may remain unnoticed due to low penetrance or no signs of disease at all; regional prevalence rather than national prevalence should be considered in cost-efficacy models to approach preventive screening in the asymptomatic population and genetic screening strategies will have to deal with the genetic heterogeneity of ATP7B in the general population and in patients.

The microbiome(s) and cancer: know thy neighbor(s).

The human microbiome is essential for the correct functioning of many host physiological processes, including metabolic regulation and immune responses. Increasing evidence indicates that the microbiome may also influence cancer development, progression, and the response to therapy. Although most studies have focused on the effect of the gut microbiome, many other organs such as the skin, vagina, and lungs harbor their own microbiomes that are different from the gut. Tumor development has been associated with dysbiosis not only in the gut but also in the tissue from which the tumor originated. Furthermore, the intratumoral microbiota has a distinct signature in each tumor type. Here, we review the mechanisms by which the organ-specific microbiome can contribute to carcinogenesis: release of toxins that cause DNA damage and barrier failure; alteration of immune responses to create a local inflammatory or immunosuppressive environment; and regulation of nutrient levels in the tumor microenvironment through metabolite production and consumption. Solving the puzzle of how the microbiome influences the carcinogenesis process and treatment response requires an understanding of the two ways the microbiome can interact with cancer cells and the tumor microenvironment: through systemic effects exerted by the gut microbiota and local effects of the intratumoral microbiota. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Effect of Sex Differences on Computed Tomography Findings in Adults With Cystic Fibrosis: A Multicenter Study.

BACKGROUND: The survival of women with cystic fibrosis (CF) is lower than that of men by approximately 5 years. While various factors have been put forward to account for this discrepancy, no specific reasons have been established. Our hypothesis was that anatomical-structural involvement is more pronounced in women with CF than in men and that this is reflected in thoracic HRCT findings. MATERIAL AND METHODS: We performed a prospective multicentre study, in which adult patients were consecutively included over 18 months. Chest HRCT was performed, and findings were scored by 2 thoracic radiologists using the modified Bhalla system. We also studied respiratory function, applied the CFQR 14+ questionnaire, and collected clinical variables. RESULTS: Of the 360 patients followed up in the participating units, 160 were eventually included. Mean age was 28 years, and 47.5% were women. The mean±SD global score on the modified Bhalla score was 13.7±3.8 in women and 15.2±3.8 in men (p=0.024). The highest scores were observed for sacculations, bronchial generations, and air trapping in women. Women had lower BMI, %FEV1, %FVC, and %DLCO. Similarly, the results for the respiratory domain in CFQR 14+ were worse in women, who also had more annual exacerbations. CONCLUSIONS: This is the first study to provide evidence of the implication of sex differences in HRCT findings in patients with CF. Women with CF present a more severe form of the disease that results in more frequent exacerbations, poorer functional and nutritional outcomes, deterioration of quality of life, and greater structural damage.

Wilson disease: revision of diagnostic criteria in a clinical series with great genetic homogeneity.

BACKGROUND: Wilson disease is an autosomal recessive disorder of copper metabolism caused by mutations in the ATP7B gene. An early diagnosis is crucial to prevent evolution of the disease, as implantation of early therapeutic measures fully prevents its symptoms. As population genetics data predict a higher than initially expected prevalence, it was important to define the basic diagnostic tools to approach population screening. METHODS: A highly genetically homogeneous cohort of 70 patients, belonging to 50 unrelated families, has been selected as a framework to analyze all their clinical, biochemical and genetic characteristics, to define the disease in our population, with an estimated prevalence of 1 in 12,369, and determine the most useful features that reach diagnostic value. RESULTS: Serum ceruloplasmin below 11.5 mg/dL and cupremia below 60 µg/mL, were the best analytical predictors of the disease in asymptomatic individuals, while cupruria or hepatic copper determination were less powerful. Genetic analysis reached a conclusive diagnosis in all 65 patients available for complete testing. Of them, 48 were carriers of at least one p.Leu708Pro mutant allele, with 24 homozygotes. Nine patients carried a promoter deletion mutation, revealing that extended sequencing beyond the ATP7B gene-coding region is essential. All mutations caused hepatic damage since early ages, increasing its severity as diagnosis was delayed, and neurological symptoms appear. CONCLUSION: Serum ceruloplasmin determination followed by genetic screening would reduce costs and favor the prioritization of non-invasive procedures to reach a definitive diagnosis, even for asymptomatic cases.

Predictive value of the modified Bhalla score for assessment of pulmonary exacerbations in adults with cystic fibrosis.

OBJECTIVES: The objective of this study was to analyze the predictive value of the modified Bhalla score in high-resolution computed tomography (HRCT) for assessment of pulmonary exacerbations (PEx) in cystic fibrosis (CF) patients. We also describe the relationship between this score and pulmonary function test results. METHODS: We performed a multicenter and prospective study where adult patients with CF were included consecutively over 18 months. All patients underwent HRCT with acquisition in inspiration and expiration. The results were analyzed by an expert radiologist who assigned a modified Bhalla score value. Lung function was also assessed, and clinical variables were collected. Follow-up lasted approximately 1 year, and PEx were registered. RESULTS: The study population comprised 160 subjects selected from 360 CF patients monitored in the participating CF units. The mean age was 28 years, 47.5% were women, and mean forced expiratory volume in 1 s (FEV1) was 67.5%. The mean global modified Bhalla score was 14.5 ± 0.31 points. Pulmonary function test (PFT) results and the modified Bhalla score correlated well, mainly forced vital capacity (FVC) and FEV1. We constructed a statistical model based on the overall Bhalla score to predict the number of PEx. CONCLUSIONS: The overall modified Bhalla score can predict future PEx in CF patients. This useful tool can help to prevent PEx in higher risk patients. KEY POINTS: • Pulmonary function test results and the modified Bhalla score correlated well with FVC and FEV1. • The total modified Bhalla score can predict the number of exacerbations in adult CF patients. • Our findings highlight the need to establish a unified protocol for chest HRCT during the follow-up of adult patients with CF in order to anticipate possible complications and determine their impact on pulmonary function.

PHGDH supports liver ceramide synthesis and sustains lipid homeostasis.

BACKGROUND: d-3-phosphoglycerate dehydrogenase (PHGDH), which encodes the first enzyme in serine biosynthesis, is overexpressed in human cancers and has been proposed as a drug target. However, whether PHGDH is critical for the proliferation or homeostasis of tissues following the postnatal period is unknown. METHODS: To study PHGDH inhibition in adult animals, we developed a knock-in mouse model harboring a PHGDH shRNA under the control of a doxycycline-inducible promoter. With this model, PHGDH depletion can be globally induced in adult animals, while sparing the brain due to poor doxycycline delivery. RESULTS: We found that PHGDH depletion is well tolerated, and no overt phenotypes were observed in multiple highly proliferative cell compartments. Further, despite detectable knockdown and impaired serine synthesis, liver and pancreatic functions were normal. Interestingly, diminished PHGDH expression reduced liver serine and ceramide levels without increasing the levels of deoxysphingolipids. Further, liver triacylglycerol profiles were altered, with an accumulation of longer chain, polyunsaturated tails upon PHGDH knockdown. CONCLUSIONS: These results suggest that dietary serine is adequate to support the function of healthy, adult murine tissues, but PHGDH-derived serine supports liver ceramide synthesis and sustains general lipid homeostasis.

COVID-19 in a Hispanic Woman.

Since making its debut on the global stage in December 2019, coronavirus disease 2019 (COVID-19) has afflicted nearly 4 million people and caused hundreds of thousands of deaths. Case reports and case series depicting the clinical effects of the causative virus-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-have been published, yet few demonstrate the cytopathologic alterations of this disease. We present a clinical-pathologic correlation report of a previously healthy Hispanic woman with laboratory-confirmed COVID-19 who had typical features of acute respiratory distress syndrome (ARDS) and also showed cardiac abnormalities thought to represent fulminant viral myocarditis. Congruent with the ARDS clinical impression, autopsy findings were remarkable for extensive and markedly severe acute lung injury consistent with viral pneumonia, characterized by diffuse alveolar damage, pulmonary infarction, severe pulmonary edema, desquamation of pneumocytes with intra-alveolar aggregation, and pneumocyte morphologic alterations suggestive of viral cytopathic effect. However, there was incongruence between the clinical impression and the cardiovascular pathology findings in that viral myocarditis was not detected on histopathologic evaluation. This case highlights the importance of pathologic corroboration of the clinical impression and, in addition, illuminates the key role autopsy plays during a pandemic by providing valuable insight into viral pathology in tissues.

The Response to Stimulation in Neurons and Astrocytes.

The brain uses mainly glucose as fuel with an index of glucose to oxygen utilization close to 6, the maximal index if all glucose was completely oxidized. However, this high oxidative index, contrasts with the metabolic traits of the major cell types in the brain studied in culture, neurons and astrocytes, including the selective use of the malate-aspartate shuttle (MAS) in neurons and the glycerol-phosphate shuttle in astrocytes. Metabolic interactions among these cell types may partly explain the high oxidative index of the brain. In vivo, neuronal activation results in a decrease in the oxygen glucose index, which has been attributed to a stimulation of glycolysis and lactate production in astrocytes in response to glutamate uptake (astrocyte-neuron lactate shuttle, ANLS). Recent findings indicate that this is accompanied with a stimulation of pyruvate formation and astrocyte respiration, indicating that lactate formation is not the only astrocytic response to neuronal activation. ANLS proposes that neurons utilize lactate produced by neighboring astrocytes. Indeed, neurons can use lactate to support an increase in respiration with different workloads, and this depends on the Ca2+ activation of MAS. However, whether this activation operates in the brain, particularly at high stimulation conditions, remains to be established.

Calcium Deregulation and Mitochondrial Bioenergetics in GDAP1-Related CMT Disease.

The pathology of Charcot-Marie-Tooth (CMT), a disease arising from mutations in different genes, has been associated with an impairment of mitochondrial dynamics and axonal biology of mitochondria. Mutations in ganglioside-induced differentiation-associated protein 1 (GDAP1) cause several forms of CMT neuropathy, but the pathogenic mechanisms involved remain unclear. GDAP1 is an outer mitochondrial membrane protein highly expressed in neurons. It has been proposed to play a role in different aspects of mitochondrial physiology, including mitochondrial dynamics, oxidative stress processes, and mitochondrial transport along the axons. Disruption of the mitochondrial network in a neuroblastoma model of GDAP1-related CMT has been shown to decrease Ca2+ entry through the store-operated calcium entry (SOCE), which caused a failure in stimulation of mitochondrial respiration. In this review, we summarize the different functions proposed for GDAP1 and focus on the consequences for Ca2+ homeostasis and mitochondrial energy production linked to CMT disease caused by different GDAP1 mutations.

CYP2C19 or CYP3A5 Genotyping Does Not Predict Clinical Response to Clopidogrel.

Along with aspirin, clopidogrel has been a widely used antiplatelet therapeutic regimen. Although generally well tolerated, its efficacy varies among individuals, with the main hypothesis that its bioavailability relies on its bioconversion to the active compound, which, in turn, depends on the genetic background and/or interactions with other drugs. To determine which factors influenced response in our patients, 368 patients receiving combined antiaggregation therapy with aspirin and clopidogrel were followed for 1 year to record 30 novel cardiovascular acute events. This clinical relapse was considered a surrogate end point to measure therapeutic response under the influence of the CYP2C19*2, *3, and *17 and CYP3A5*3 alleles, as well as the effects of concomitant medication and the presence of known cardiovascular risk factors and comorbidity. We show that either single CYP2C19 or CYP3A5 genotyping or combined were not useful to predict clinical efficacy in this cohort. Rather than genetic testing, we have found that clinical observations such as suffering type 2 diabetes mellitus requiring insulin, having several vessels affected, and concurrent medication with calcium channel blockers, regardless of CYP3A5 genotype or drug class were, in that order, the strongest independent predictors of disease relapse.

H- ras deletion protects against angiotensin II-induced arterial hypertension and cardiac remodeling through protein kinase G-Iß pathway activation.

Ras proteins regulate cell survival, growth, differentiation, blood pressure, and fibrosis in some organs. We have demonstrated that H- ras gene deletion produces mice hypotension via a soluble guanylate cyclase-protein kinase G (PKG)-dependent mechanism. In this study, we analyzed the consequences of H- ras deletion on cardiac remodeling induced by continuous angiotensin II (AngII) infusion and the molecular mechanisms implied. Left ventricular posterior wall thickness and mass and cardiomyocyte cross-sectional area were similar between AngII-treated H-Ras knockout (H -ras-/-) and control wild-type (H -ras+/+) mice, as were extracellular matrix protein expression. Increased cardiac PKG-Iß protein expression in H -ras-/- mice suggests the involvement of this protein in heart protection. Ex vivo experiments on cardiac explants could support this mechanism, as PKG blockade blunted protection against AngII-induced cardiac hypertrophy and fibrosis markers in H -ras-/- mice. Genetic modulation studies in cardiomyocytes and cardiac and embryonic fibroblasts revealed that the lack of H-Ras down-regulates the B-RAF/MEK/ERK pathway, which induces the glycogen synthase kinase-3ß-dependent activation of the transcription factor, cAMP response element-binding protein, which is responsible for PKG-Iß overexpression in H -ras-/- mouse embryonic fibroblasts. This study demonstrates that H- ras deletion protects against AngII-induced cardiac remodeling, possibly via a mechanism in which PKG-Iß overexpression could play a partial role, and points to H-Ras and/or downstream proteins as potential therapeutic targets in cardiovascular disease.-Martín-Sánchez, P., Luengo, A., Griera, M., Orea, M. J., López-Olañeta, M., Chiloeches, A., Lara-Pezzi, E., de Frutos, S., Rodríguez-Puyol, M., Calleros, L., Rodríguez-Puyol, D. H- ras deletion protects against angiotensin II-induced arterial hypertension and cardiac remodeling through protein kinase G-Iß pathway activation.

Novel Marfan Syndrome-Associated Mutation in the FBN1 Gene Caused by Parental Mosaicism and Leading to Abnormal Limb Patterning.

Marfan syndrome is an autosomal dominant disorder of the connective tissue caused by mutations in the fibrillin-1 (FBN1) gene. Mutations affecting cysteine residues within the epidermal growith factor-like calcium-binding domains (EGF_CA) of FBN1 are associated with Marfan syndrome features and, especially, with ectopia lentis. We report a novel substitution, affecting the first cysteine of an EGF_CA-binding module encoded by exon 63 of FBN1 (C2571Y), in a patient presenting with typical Marfan syndrome features but without ectopia lentis. The involvement of this particular carboxi-terminal domain in bone morphogenetic protein signaling is evidenced by patterning defects in the apendicular skeleton shown by the gain of a phalange at digit 1 and the fusion of some wrist bones. Although the mutation appeared as sporadic, detailed analysis revealed that the asymptomatic father was a gonosomal mosaic, and that aproximately 25% of his body cells carry the mutation. Based on this and previous evidence on the origin of sporadic mutations, we would like to stress the importance of detailed parental genetic screening, so the risk of recurrence may be evaluated.

T-Cell Intracellular Antigens and Hu Antigen R Antagonistically Modulate Mitochondrial Activity and Dynamics by Regulating Optic Atrophy 1 Gene Expression.

Mitochondria undergo frequent morphological changes to control their function. We show here that T-cell intracellular antigens (TIA1b/TIARb) and Hu antigen R (HuR) have antagonistic roles in mitochondrial function by modulating the expression of mitochondrial shaping proteins. Expression of TIA1b/TIARb alters the mitochondrial dynamic network by enhancing fission and clustering, which is accompanied by a decrease in respiration. In contrast, HuR expression promotes fusion and cristae remodeling and increases respiratory activity. Mechanistically, TIA proteins downregulate the expression of optic atrophy 1 (OPA1) protein via switching of the splicing patterns of OPA1 to facilitate the production of OPA1 variant 5 (OPA1v5). Conversely, HuR enhances the expression of OPA1 mRNA isoforms through increasing steady-state levels and targeting translational efficiency at the 3' untranslated region. Knockdown of TIA1/TIAR or HuR partially reversed the expression profile of OPA1, whereas knockdown of OPA1 or overexpression of OPA1v5 provoked mitochondrial clustering. Middle-term expression of TIA1b/TIARb triggers reactive oxygen species production and mitochondrial DNA damage, which is accompanied by mitophagy, autophagy, and apoptosis. In contrast, HuR expression promotes mitochondrion-dependent cell proliferation. Collectively, these results provide molecular insights into the antagonistic functions of TIA1b/TIARb and HuR in mitochondrial activity dynamics and suggest that their balance might contribute to mitochondrial physiopathology.