Metabolic reprogramming by the S-nitroso-CoA reductase system protects against kidney injury.

Endothelial nitric oxide synthase (eNOS) is protective against kidney injury, but the molecular mechanisms of this protection are poorly understood1,2. Nitric oxide-based cellular signalling is generally mediated by protein S-nitrosylation, the oxidative modification of Cys residues to form S-nitrosothiols (SNOs). S-nitrosylation regulates proteins in all functional classes, and is controlled by enzymatic machinery that includes S-nitrosylases and denitrosylases, which add and remove SNO from proteins, respectively3,4. In Saccharomyces cerevisiae, the classic metabolic intermediate co-enzyme A (CoA) serves as an endogenous source of SNOs through its conjugation with nitric oxide to form S-nitroso-CoA (SNO-CoA), and S-nitrosylation of proteins by SNO-CoA is governed by its cognate denitrosylase, SNO-CoA reductase (SCoR)5. Mammals possess a functional homologue of yeast SCoR, an aldo-keto reductase family member (AKR1A1)5 with an unknown physiological role. Here we report that the SNO-CoA-AKR1A1 system is highly expressed in renal proximal tubules, where it transduces the activity of eNOS in reprogramming intermediary metabolism, thereby protecting kidneys against acute kidney injury. Specifically, deletion of Akr1a1 in mice to reduce SCoR activity increased protein S-nitrosylation, protected against acute kidney injury and improved survival, whereas this protection was lost when Enos (also known as Nos3) was also deleted. Metabolic profiling coupled with unbiased mass spectrometry-based SNO-protein identification revealed that protection by the SNO-CoA-SCoR system is mediated by inhibitory S-nitrosylation of pyruvate kinase M2 (PKM2) through a novel locus of regulation, thereby balancing fuel utilization (through glycolysis) with redox protection (through the pentose phosphate shunt). Targeted deletion of PKM2 from mouse proximal tubules recapitulated precisely the protective and mechanistic effects of S-nitrosylation in Akr1a1-/- mice, whereas Cys-mutant PKM2, which is refractory to S-nitrosylation, negated SNO-CoA bioactivity. Our results identify a physiological function of the SNO-CoA-SCoR system in mammals, describe new regulation of renal metabolism and of PKM2 in differentiated tissues, and offer a novel perspective on kidney injury with therapeutic implications.

Author Correction: Metabolic reprogramming by the S-nitroso-CoA reductase system protects against kidney injury.

Change history: In Fig. 1j of this Letter, one data point was inadvertently omitted from the graph for the acute kidney injury (AKI), double knockout (-/-), S-nitrosothiol (SNO) condition at a nitrosylation level of 25.9 pmol mg-1 and the statistical significance given of P = 0.0221 was determined by Fisher's test instead of P = 0.0032 determined by Tukey's test (with normalization for test-day instrument baseline). Figure 1 and its Source Data have been corrected online.

AKR1A1 is a novel mammalian S-nitroso-glutathione reductase.

Oxidative modification of Cys residues by NO results in S-nitrosylation, a ubiquitous post-translational modification and a primary mediator of redox-based cellular signaling. Steady-state levels of S-nitrosylated proteins are largely determined by denitrosylase enzymes that couple NAD(P)H oxidation with reduction of S-nitrosothiols, including protein and low-molecular-weight (LMW) S-nitrosothiols (S-nitroso-GSH (GSNO) and S-nitroso-CoA (SNO-CoA)). SNO-CoA reductases require NADPH, whereas enzymatic reduction of GSNO can involve either NADH or NADPH. Notably, GSNO reductase (GSNOR, Adh5) accounts for most NADH-dependent GSNOR activity, whereas NADPH-dependent GSNOR activity is largely unaccounted for (CBR1 mediates a minor portion). Here, we de novo purified NADPH-coupled GSNOR activity from mammalian tissues and identified aldo-keto reductase family 1 member A1 (AKR1A1), the archetypal mammalian SNO-CoA reductase, as a primary mediator of NADPH-coupled GSNOR activity in these tissues. Kinetic analyses suggested an AKR1A1 substrate preference of SNO-CoA > GSNO. AKR1A1 deletion from murine tissues dramatically lowered NADPH-dependent GSNOR activity. Conversely, GSNOR-deficient mice had increased AKR1A1 activity, revealing potential cross-talk among GSNO-dependent denitrosylases. Molecular modeling and mutagenesis of AKR1A1 identified Arg-312 as a key residue mediating the specific interaction with GSNO; in contrast, substitution of the SNO-CoA-binding residue Lys-127 minimally affected the GSNO-reducing activity of AKR1A1. Together, these findings indicate that AKR1A1 is a multi-LMW-SNO reductase that can distinguish between and metabolize the two major LMW-SNO signaling molecules GSNO and SNO-CoA, allowing for wide-ranging control of protein S-nitrosylation under both physiological and pathological conditions.

Identification of S-nitroso-CoA reductases that regulate protein S-nitrosylation.

Coenzyme A (CoA) mediates thiol-based acyl-group transfer (acetylation and palmitoylation). However, a role for CoA in the thiol-based transfer of NO groups (S-nitrosylation) has not been considered. Here we describe protein S-nitrosylation in yeast (heretofore unknown) that is mediated by S-nitroso-CoA (SNO-CoA). We identify a specific SNO-CoA reductase encoded by the alcohol dehydrogenase 6 (ADH6) gene and show that deletion of ADH6 increases cellular S-nitrosylation and alters CoA metabolism. Further, we report that Adh6, acting as a selective SNO-CoA reductase, protects acetoacetyl-CoA thiolase from inhibitory S-nitrosylation and thereby affects sterol biosynthesis. Thus, Adh6-regulated, SNO-CoA-mediated protein S-nitrosylation provides a regulatory mechanism paralleling protein acetylation. We also find that SNO-CoA reductases are present from bacteria to mammals, and we identify aldo-keto reductase 1A1 as the mammalian functional analog of Adh6. Our studies reveal a novel functional class of enzymes that regulate protein S-nitrosylation from yeast to mammals and suggest that SNO-CoA-mediated S-nitrosylation may subserve metabolic regulation.

Comparison of oral ibuprofen with oral indomethacin for PDA closure in Indian preterm neonates: a randomized controlled trial.

Oral ibuprofen is being used as an alternative to indomethacin in medical management of patent ductus arteriosus (PDA), but limited data exist on oral efficacy of these drugs for PDA closure in India. To assess and compare the efficacy of oral ibuprofen and oral indomethacin for PDA closure in preterm Indian neonates, we designed a randomized controlled study on clinically diagnosed and echocardiographically confirmed hemodynamically significant PDA in preterm neonates. Patients were assigned to receive either oral ibuprofen at a dosage of 10, 5, 5 mg/kg every 24 h or three doses of oral indomethacin (0.20-0.25 mg/kg every 24 h) starting on the third day of life or when diagnosed. A second course of ibuprofen/indomethacin was given, if PDA failed to close within 48 h after the first course. Patients were monitored for complications like oliguria, bleeding, necrotizing enterocolitis, intraventricular hemorrhage, oxygen dependency, and gastrointestinal side effects. The baseline characteristics were comparable in both groups. Of the 83 children enrolled, 57.8 % received oral ibuprofen and 42.1 % received oral indomethacin. The overall closure rate of PDA was 60 and 65.7 % in the ibuprofen and indomethacin groups, respectively. Closure rate was significantly higher when the drugs were administered at an early postnatal age (<8 days) (83.3 % [p = 0.02] in the indomethacin group and 75 % [p = 0.03] in the ibuprofen group) in neonates >28 weeks (ibuprofen group 66.7 % [p = 0.02]; indomethacin group 65.5 % [p = 0.04]) and in babies with birth weight >1,000 g (ibuprofen group 62.2 %; indomethacin group 70 % [p = 0.04 in both groups]). Complications were similar in both groups. The efficacy of both drugs was similar. Poor closure in our study could be because of genetic differences in pharmacokinetics of drug metabolism in the Indian population. Regimens with higher doses or increased duration of treatment may increase the frequency of closure. Studies with larger numbers of subjects with evaluation of pharmacokinetic parameters are therefore required.

The Psychosocial Effects of Lockdown Due to the COVID-19 Pandemic on Children in 2021.

Objectives The COVID-19 pandemic led to a nationwide lockdown that isolated numerous children and adolescents, significantly affecting their mental well-being. Therefore, this study aimed to assess the challenges faced by children during the pandemic and identify the potential contributing factors. Additionally, given the existing concerns surrounding the mental health of female children and adolescents, our study aimed to investigate the presence of sex-based disparities in children's observed emotional and behavioral difficulties during the COVID-19 lockdown. Methods Participants in this study were parents of children aged 6-17 years. An observational cross-sectional study was conducted through verbal administration of a validated semi-structured questionnaire, the Parent Report Measure, from June 2021 to August 2021 at a nearby community health center. The questionnaire collected socio-demographic details and utilized the Strengths and Difficulties Questionnaire (SDQ), a screening tool to assess children's emotional and behavioral aspects during the six-month lockdown period. The responses were then analyzed using appropriate statistical tools like SPSS statistics, and cumulative SDQ scores were used to categorize participants. Results Out of the total 280 responses analyzed, the prosocial subscale exhibited the highest number of abnormal responses, 73 (26.1%), followed by conduct (42; 15%), hyperactivity (41; 14.6%), and peer (41; 14.6%) subscales. These results indicated that children displayed decreased empathy towards others, restlessness, fidgetiness, reduced attention span, frequent tantrums, and a preference for solitary activities. Furthermore, there was a significant association between abnormal subscale scores and the sex of children. Females showed a considerably higher prevalence of emotional problems (172; 61.5%) than males. Among the behavioral responses, a more significant proportion of females displayed abnormal scores in the conduct subscale (170; 60.7%), while abnormal hyperactivity scores were more frequently observed among males (178; 63.4%). Regarding the peer problems subscale, the proportion of females was slightly higher than males (150; 53.7%) and nearly equal in the prosocial domain. A more significant proportion of females displayed abnormal scores for overall difficulties 144 (51.5%), indicating a notable sex-based disparity. Conclusion Our findings highlight the pandemic's significant impact on many children's psychological well-being. The results emphasize the need for targeted interventions to address the mental health concerns that arose in this population. The observed disparity in emotional and behavioral difficulties among female children is particularly concerning, highlighting the need for gender-sensitive support and care. Various strategies can be helpful, such as virtual support groups, indoor recreational activities, reduced screen time and excessive news consumption, and effective communication with parents. Furthermore, our study also indicates the need to dive deep into such areas of pediatric research to understand and plan timely interventions.

RNA Interference Therapeutics for Hereditary Amyloidosis: A Narrative Review of Clinical Trial Outcomes and Future Directions.

Hereditary transthyretin amyloidosis (ATTR) is an autosomal dominant, life-threatening genetic disorder caused by a single-nucleotide variant in the transthyretin gene. This mutation leads to the misfolding and deposition of amyloid in various body organs. Both mutant and wild-type transthyretin contribute to the resulting polyneuropathy and cardiomyopathy, leading to significant sensorimotor disturbances and severe cardiac conditions such as heart failure and arrhythmias, thereby impacting quality of life. Despite several treatments, including orthotopic liver transplantation and transthyretin tetramer stabilizers, their limitations persisted until the introduction of RNA interference (RNAi). RNAi, a means to regulate mRNA stability and translation of targeted genes, has brought about significant changes in treatment strategies for ATTR with the introduction of patisiran in 2018. This study reviews patisiran, vutrisiran, inotersen, and eplontersen, developed for the treatment of ATTR. It provides an overview of the clinical trial outcomes, focusing mainly on quality of life, adverse reactions, and the future of RNAi-based therapies.

Myeloid Krüppel-like factor 4 deficiency augments atherogenesis in ApoE-/- mice--brief report.

OBJECTIVE: To investigate the role of Krüppel-like factor 4 (KLF4), an essential transcriptional regulator of macrophage polarization (M1/M2), in the pathogenesis of atherosclerosis. METHODS AND RESULTS: Despite the acknowledged importance of macrophages in atherosclerosis, the role of M1 (classically activated or proinflammatory) versus M2 (alternatively activated or anti-inflammatory) macrophages in this process remains incompletely understood. We recently identified KLF4 as a regulator of macrophage subset specification; that is, KLF4 promotes M2 and inhibits M1 phenotype. Here, we provide evidence that KLF4-deficient macrophages exhibit enhanced proinflammatory activation and foam cell formation in response to oxidized lipids. In vivo, myeloid KLF4-deficient mice (ApoE(-/-) background) develop significantly more vascular inflammation and atherosclerotic lesion formation. CONCLUSIONS: Our findings identify myeloid KLF4 as an essential regulator of vascular inflammation and experimental atherogenesis.

Identification of a Selective SCoR2 Inhibitor That Protects Against Acute Kidney Injury.

Acute kidney injury (AKI) is associated with high morbidity and mortality, and no drugs are available clinically. Metabolic reprogramming resulting from the deletion of S-nitroso-coenzyme A reductase 2 (SCoR2; AKR1A1) protects mice against AKI, identifying SCoR2 as a potential drug target. Of the few known inhibitors of SCoR2, none are selective versus the related oxidoreductase AKR1B1, limiting therapeutic utility. To identify SCoR2 (AKR1A1) inhibitors with selectivity versus AKR1B1, analogs of the nonselective (dual 1A1/1B1) inhibitor imirestat were designed, synthesized, and evaluated. Among 57 compounds, JSD26 has 10-fold selectivity for SCoR2 versus AKR1B1 and inhibits SCoR2 potently through an uncompetitive mechanism. When dosed orally to mice, JSD26 inhibited SNO-CoA metabolic activity in multiple organs. Notably, intraperitoneal injection of JSD26 in mice protected against AKI through S-nitrosylation of pyruvate kinase M2 (PKM2), whereas imirestat was not protective. Thus, selective inhibition of SCoR2 has therapeutic potential to treat acute kidney injury.

Neurofibromin homologs Ira1 and Ira2 affect glycerophosphoinositol production and transport in Saccharomyces cerevisiae.

Saccharomyces cerevisiae produces extracellular glycerophosphoinositol through phospholipase-mediated turnover of phosphatidylinositol and transports glycerophosphoinositol into the cell upon nutrient limitation. A screening identified the RAS GTPase-activating proteins Ira1 and Ira2 as required for utilization of glycerophosphoinositol as the sole phosphate source, but the RAS/cyclic AMP pathway does not appear to be involved in the growth phenotype. Ira1 and Ira2 affect both the production and transport of glycerophosphoinositol.

Pathway to care and clinical profile of children with attention-deficit hyperactivity disorder in New Delhi, India.

BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) is a common childhood neurobehavioral disorder, which may cause impairment in multiple domains. Understanding the pathway to care helps in planning effective early interventions. The study aims to provide a quantitative description of the factors affecting the help-seeking pathway. MATERIALS AND METHODS: The study was conducted at an outpatients department of a tertiary care multispecialty hospital. Fifty consecutive consenting children aged 5-15 years were screened and diagnosed for ADHD using Conners' Parent Rating Scale-Revised: Short Form, Diagnostic and Statistical Manual of Mental Disorders fourth edition text revision criteria, and Kiddie Schedule for affective disorders and schizophrenia. A semi-structured questionnaire was used to study the pathway of care, using the WHO template. The data were analyzed using appropriate parametric and nonparametric tests in SPSS software. RESULTS: The average delay from the onset of the illness to first consultation with a qualified health professional was 2.32 ± 1.9 years. Children with an urban background, from a nuclear family, with literate mothers, with a family income of more than Rs. 30,000/month, having hyperactive and combined type of ADHD, and who were referred by school teachers presented significantly earlier. The main source of referrals were school teachers and general medical practitioners. The most common parental beliefs for delay were the views that the "child is naughty" and that "hyperactivity is part of normal growth." CONCLUSION: Parents' help-seeking behavior is affected by different sociocultural beliefs. Such factors as the lack of recognition and awareness of ADHD, resulting in the delay in seeking treatment should be addressed through health promotion programs.

Knowledge and awareness regarding menstruation and HIV/AIDS among schoolgoing adolescent girls.

INTRODUCTION: Menstruation in our country is associated with various myths and restrictions leading to lack of awareness among adolescent girls. Insufficient menstrual hygiene practices are the cause of stress associated with menstruation and reproductive tract infections. Sexually transmitted infections and HIV/AIDS are not openly discussed in our society making adolescents vulnerable to them. AIM: To assess the knowledge of school going adolescent girls regarding menstrual hygiene and HIV/AIDS. MATERIALS AND METHODS: Girls studying in class 8th-12th standard and who have attained menarche were included in the study. A predesigned questionnaire, which consisted of questions related to menstrual awareness and knowledge about HIV/AIDS was used for data collection. Data was analysed using SPSS software and results were interpreted into percentages. RESULTS: 282 girls took part in the study. Mean age of girls was 14.70 ± 1.5 years. Median age of girls was 15 years. Knowledge regarding menstrual hygiene and HIV/AIDS was found to be only satisfactory leaving a scope of improvement. Mother was the main source of information regarding both menstruation and HIV/AIDS. CONCLUSION: A comprehensive health education programme involving mothers is required to remove various misconceptions and taboos associated with menstruation and make it a pleasant experience for adolescent girls. Information, education and awareness programmes need to be strengthened to spread awareness regarding HIV/AIDS.

Effect of Poly Unsaturated Fatty Acids Administration on Children with Attention Deficit Hyperactivity Disorder: A Randomized Controlled Trial.

INTRODUCTION: Attention Deficit Hyperactivity Disorder (ADHD) is a common disorder of childhood. Studies have indicated nutritional deficiencies, particularly Poly Unsaturated Fatty Acids (PUFA) deficiency in these children and have suggested supplementation with PUFA for clinical improvement. AIM: The present study aimed at evaluating the effect of PUFA administration in Indian children with ADHD. SETTINGS AND DESIGN: The study was conducted in the paediatrics and psychiatry departments of a tertiary care hospital. We conducted a prospective double blind randomized control trial on children aged 4-11 years, diagnosed with ADHD according to DSM-IV TR criterias and Kiddie-Schedule for Affective Disorders and Schizophrenia - Present and lifetime version. MATERIALS AND METHODS: The study subjects were randomized into study and control groups. The control group was administered Atomoxetine, while the study group received Atomoxetine along with Eicosapentanoic acid (EPA) and Docosahexanoic acid (DHA). Both groups were followed up every 2 weeks over the next 4 months using Conner's Parent Rating Scale - Revised (CPRS-R). STATISTICAL ANALYSIS: The data was carefully analysed by SPSS (17th version) software with the help of a statistician. Confidence interval of 95% was used. The complete data was analysed using appropriate parametric and non parametric tests. Correlation was done between various socio-demographic and illness related parameters. For all analyses, probability of 5% or less was assumed to represent statistical significance. RESULTS: Fifty children diagnosed with ADHD were randomized to study group (n=25) and control group (n=25). The study group had greater reduction in ADHD scores as compared to the control group, although not statistically significant (p = 0.08). Improvement was more significant in male study subjects with combined type of ADHD. CONCLUSION: It may be concluded that PUFA supplementation improves the symptoms of ADHD. However, the effect is not clinically significant if supplementation is not given for prolonged duration and in adequate doses.

Kruppel-like factor 4 is critical for transcriptional control of cardiac mitochondrial homeostasis.

Mitochondrial homeostasis is critical for tissue health, and mitochondrial dysfunction contributes to numerous diseases, including heart failure. Here, we have shown that the transcription factor Kruppel-like factor 4 (KLF4) governs mitochondrial biogenesis, metabolic function, dynamics, and autophagic clearance. Adult mice with cardiac-specific Klf4 deficiency developed cardiac dysfunction with aging or in response to pressure overload that was characterized by reduced myocardial ATP levels, elevated ROS, and marked alterations in mitochondrial shape, size, ultrastructure, and alignment. Evaluation of mitochondria isolated from KLF4-deficient hearts revealed a reduced respiration rate that is likely due to defects in electron transport chain complex I. Further, cardiac-specific, embryonic Klf4 deletion resulted in postnatal premature mortality, impaired mitochondrial biogenesis, and altered mitochondrial maturation. We determined that KLF4 binds to, cooperates with, and is requisite for optimal function of the estrogen-related receptor/PPARγ coactivator 1 (ERR/PGC-1) transcriptional regulatory module on metabolic and mitochondrial targets. Finally, we found that KLF4 regulates autophagy flux through transcriptional regulation of a broad array of autophagy genes in cardiomyocytes. Collectively, these findings identify KLF4 as a nodal transcriptional regulator of mitochondrial homeostasis.

Failure of secondary prophylaxis with erythromycin in rheumatic heart disease.

BACKGROUND: Erythromycin is recommended for secondary prophylaxis in children with rheumatic heart disease, who are allergic to penicillin. CASE CHARACTERISTICS: A 9-year-old girl, with rheumatic heart disease, on secondary prophylaxis with erythromycin 250 mg BD, presented with acute rheumatic fever. OUTCOME: Responded to steroids and started on a higher dose (250 mg TDS) of erythromycin for secondary prophylaxis. MESSAGE: There is need to document the resistance of group A streptococci to erythromycin.

Enzymatic mechanisms regulating protein S-nitrosylation: implications in health and disease.

Nitric oxide participates in cellular signal transduction largely through S-nitrosylation of allosteric and active-site cysteine thiols within proteins, forming S-nitroso-proteins (SNO-proteins). S-nitrosylation of proteins has been demonstrated to affect a broad range of functional parameters including enzymatic activity, subcellular localization, protein-protein interactions, and protein stability. Analogous to other ubiquitous posttranslational modifications that are regulated enzymatically, including phosphorylation and ubiquitinylation, accumulating evidence suggests the existence of enzymatic mechanisms for regulating protein S-nitrosylation. In particular, studies have led to the identification of multiple enzymes (nitrosylases and denitrosylases) that participate in targeted S-nitrosylation or denitrosylation of proteins in physiological settings. Nitrosylases are best characterized in the context of transnitrosylation in which a SNO-protein transfers an NO group to an acceptor protein (Cys-to-Cys transfer), but examples of transnitrosylation catalyzed by metalloproteins (Metal-to-Cys transfer) also exist. By contrast, denitrosylases remove the NO group from SNO-proteins, ultimately using reducing equivalents derived from NADH or NADPH. Here, we focus on the recent discoveries of nitrosylases and denitrosylases and the notion that their aberrant activities may play roles in health and disease.