TMBIM5 is the Ca2+ /H+ antiporter of mammalian mitochondria.

Mitochondrial Ca2+ ions are crucial regulators of bioenergetics and cell death pathways. Mitochondrial Ca2+ content and cytosolic Ca2+ homeostasis strictly depend on Ca2+ transporters. In recent decades, the major players responsible for mitochondrial Ca2+ uptake and release have been identified, except the mitochondrial Ca2+ /H+ exchanger (CHE). Originally identified as the mitochondrial K+ /H+ exchanger, LETM1 was also considered as a candidate for the mitochondrial CHE. Defining the mitochondrial interactome of LETM1, we identify TMBIM5/MICS1, the only mitochondrial member of the TMBIM family, and validate the physical interaction of TMBIM5 and LETM1. Cell-based and cell-free biochemical assays demonstrate the absence or greatly reduced Na+ -independent mitochondrial Ca2+ release in TMBIM5 knockout or pH-sensing site mutants, respectively, and pH-dependent Ca2+ transport by recombinant TMBIM5. Taken together, we demonstrate that TMBIM5, but not LETM1, is the long-sought mitochondrial CHE, involved in setting and regulating the mitochondrial proton gradient. This finding provides the final piece of the puzzle of mitochondrial Ca2+ transporters and opens the door to exploring its importance in health and disease, and to developing drugs modulating Ca2+ exchange.

LETM1: Essential for Mitochondrial Biology and Cation Homeostasis?

Mitochondrial function is essential for life. Therefore, it is unsurprising that perturbations in mitochondrial function have wide-ranging consequences in the cell. High-throughput screening has identified essential genes required for cellular survival and fitness. One such gene is LETM1. The undisputed function of LETM1 from yeast to human is to maintain the mitochondrial osmotic balance. Osmotic imbalance has been demonstrated to affect mitochondrial morphology, dynamics, and, more recently, metabolism. Whether conservation of osmotic homeostasis by LETM1 occurs by extrusion of excess mitochondrial potassium (K+), calcium (Ca2+), or both has been a matter of dispute over the past 10 years. In this Opinion, we report and discuss recent findings on LETM1 structure, essentiality, and function and its involvement in Wolf-Hirschhorn syndrome (WHS) and seizures.

Shared and distinct developmental pathways to ASD and ADHD phenotypes among infants at familial risk.

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are believed to share partially overlapping causal mechanisms suggesting that early risk markers may also overlap. Using latent profile analysis (LPA) in a sample of infants enriched for ASD and ADHD, we first examined the number of distinct groups of 3-year-old children, based on ADHD and ASD symptomatology. To investigate early predictors of ASD and ADHD symptom profiles, we next examined differences in trajectories of infant behaviors among the LPA classes spanning general development, negative affect, attention, activity level, impulsivity, and social behavior. Participants included 166 infants at familial risk for ASD (n = 89), ADHD (n = 38), or low-risk for both (n = 39) evaluated at 12, 18, 24, and 36 months of age. A three-class solution was selected reflecting a Typically Developing (TD) class (low symptoms; n = 108), an ADHD class (high ADHD/low ASD symptoms; n = 39), and an ASD class (high ASD/ADHD symptoms; n = 19). Trajectories of infant behaviors were generally suggestive of a gradient pattern of differences, with the greatest impairment within the ASD class followed by the ADHD class. These findings indicate a mixture of overlapping and distinct early markers of preschool ASD- and ADHD-like profiles that can be difficult to disentangle early in life.

A Comprehensive Analytical Strategy To Identify Malondialdehyde-Modified Proteins and Peptides.

Mass spectrometric-based proteomics is a powerful tool to analyze post-translationally modified proteins. Carbonylation modifications that result from oxidative lipid breakdown are a class of post-translational modifications that are poorly characterized with respect to protein targets and function. This is partly due to the lack of dedicated mass spectrometry-based technologies to facilitate the analysis of these modifications. Here, we present a comprehensive approach to identify malondialdehyde-modified proteins and peptides. Malondialdehyde is among the most abundant of the lipid peroxidation products; and malondialdehyde-derived adducts on proteins have been implicated in cardiovascular diseases, neurodegenerative disorders, and other clinical conditions. Our integrated approach targets three levels of the overall proteomic workflow: (i) sample preparation, by employing a targeted enrichment strategy; (ii) high-performance liquid chromatography, by using a gradient optimized for the separation of the modified peptides; and (iii) tandem mass spectrometry, by improving the spectral quality of very low-abundance peptides. By applying the optimized procedure to a whole cell lysate spiked with a low amount of malondialdehyde-modified proteins, we were able to identify up to 350 different modified peptides and localize the modification to a specific lysine residue. This methodology allows the comprehensive analysis of malondialdehyde-modified proteins.

Changes in Mood in New Enrollees at a Program of All-Inclusive Care for the Elderly.

OBJECTIVES: To examine changes in mood after nine months of enrollment in a Program of All-Inclusive Care for the Elderly (PACE). DESIGN: Cohort study. SETTING: Alexian Brothers PACE, St. Louis, Missouri. PARTICIPANTS: Newly enrolled patients 55 years of age and older, living in the PACE service area, eligible for nursing facility care and able to live safely in the community, with continuous care, for at least nine months (N = 182). MAIN OUTCOME MEASURES: Geriatric Depression Scale (GDS)-15 score at the pre-admission evaluation (PAE) and the nine-month evaluation (9ME). RESULTS: Of the 182 patients evaluated, 27% (n = 49) met the definition of depression as defined by the GDS-15 score of ≥ 6 at the PAE. At the 9ME, only 11% of patients met the depression criteria (P < 0.001). Of the patients who met the criteria for depression at the PAE, 80% of patients (n = 39) no longer met these criteria at the 9ME (P = 0.029). Similar findings were observed by age, gender, and race. Greater improvement was observed among those who were depressed at the PAE; the depressed cohort improved by 5.0 points (P < 0.001) on the GDS-15 scale from the PAE to the 9ME, whereas the nondepressed cohort improved by 0.6 points (P = 0.003). CONCLUSION: The use of PACE as an alternative intervention may be a good option to improve mood in older adults.

PGC1α and mitochondrial metabolism--emerging concepts and relevance in ageing and neurodegenerative disorders.

PGC1α is a transcriptional coactivator that is a central inducer of mitochondrial biogenesis in cells. Recent work highlighted that PGC1α can also modulate the composition and functions of individual mitochondria. Therefore, it is emerging that PGC1α is controlling global oxidative metabolism by performing two types of remodelling: (1) cellular remodelling through mitochondrial biogenesis, and (2) organelle remodelling through alteration in the intrinsic properties of mitochondria. The elevated oxidative metabolism associated with increased PGC1α activity could be accompanied by an increase in reactive oxygen species (ROS) that are primarily generated by mitochondria. However, increasing evidence suggests that this is not the case, as PGC1α is also a powerful regulator of ROS removal by increasing the expression of numerous ROS-detoxifying enzymes. Therefore, PGC1α, by controlling both the induction of mitochondrial metabolism and the removal of its ROS by-products, would elevate oxidative metabolism and minimize the impact of ROS on cell physiology. In this Commentary, we discuss how the biogenesis and remodelling of mitochondria that are elicited by PGC1α contribute to an increase in oxidative metabolism and the preservation of ROS homeostasis. Finally, we examine the importance of these findings in ageing and neurodegenerative disorders, conditions that are associated with impaired mitochondrial functions and ROS balance.

Malate dehydrogenase (MDH) in cancer: a promiscuous enzyme, a redox regulator, and a metabolic co-conspirator.

Malate dehydrogenase (MDH) is an essential enzyme in the tricarboxylic acid cycle that functions in cellular respiration and redox homeostasis. Recent studies indicate that MDH facilitates metabolic plasticity in tumor cells, catalyzing the formation of an oncometabolite, contributing to altered epigenetics, and maintaining redox capacity to support the rewired energy metabolism and biosynthesis that enables cancer progression. This minireview summarizes current findings on the unique supporting roles played by MDH in human cancers and provides an update on targeting MDH in cancer chemotherapy.

Uterine fibroids and Black people of African descent globally: a scoping review protocol.

INTRODUCTION: Evidence suggests that when adjusted for age and other factors such as Body Mass Index, age of first pregnancy, years since last pregnancy and alcohol consumption, Black women are three times more likely to suffer from fibroids compared with the general population. When compared with the general population, Black women experience larger uterine fibroids with an earlier onset and more frequent and severe symptoms debilitating symptoms. Reported symptoms include pelvic pain, bladder issues, and heavy and/or abnormal menstrual bleeding. For Black women in perimenopause or menopause, uterine fibroids are more likely to continue growing rather than slow or cease. To design empirical research that addresses the issue of uterine fibroids among Black people of African descent, it is important to understand the current state of literature on this issue. The objectives of this scoping review are to understand and describe the extent and type of literature available regarding Black people of African descent with uterine fibroids globally, to identify the gaps within existing literature, and to provide recommendations for future research. METHODS AND ANALYSIS: This scoping review will be conducted in accordance with JBI scoping review methodology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews Checklist. Eligibility criteria for this review include sources that involve Black people of African descent who have uterine fibroids. This review is global in context and does not include jurisdictional, geographical, regional or study setting restrictions. A comprehensive search strategy developed in collaboration with a health sciences librarian will be used to identify and retrieve relevant peer-reviewed and grey literature. Databases including CINAHL (EBSCO), MEDLINE (Ovid), Embase (Elsevier), Gender Studies Database (EBSCO), Scopus (Elsevier) and LILACS (VHL) will be searched from inception to January 2024. Unpublished studies and grey literature searches will include The Society for Women's Health Research, Black Women's Health Imperative, ProQuest Dissertations and Theses Global (ProQuest), Open Access Theses and Dissertations (OATD.org) and Google search. All relevant sources will be uploaded to Covidence and undergo title and abstract screening by two independent team members. Selected sources will then undergo full-text review by two independent team members. Sources meeting the eligibility criteria will undergo extraction by two independent team members. Thematic analysis will be used to classify the extracted data points into categories according to the purpose or objective of the source, the methods used, the geographical region or jurisdiction of the source, key findings and recommendations. The synthesis of results will align with the review objective and question using charts or tables where necessary. ETHICS AND DISSEMINATION: This scoping review does not require ethical approval. Dissemination of the review results includes the publication of a full report in a peer-reviewed journal as well as presenting the review results at local, national and international conferences. The results of the scoping review will also be disseminated through community events and social media using infographics and brochures.

An idea to explore: Augmented reality and LEGO® brick modeling in the biochemistry and cell biology classroom-two tactile ways to teach biomolecular structure-Function.

We present here two accessible ways for enhanced understanding of complex biological structures and their function in undergraduate Biology and Biochemistry classrooms. These methods can be applied for in-class instruction as well as for remote lessons, as they are cheap, easily available and easy to implement. LEGO® bricks and MERGE CUBE based augmented reality can be applied to make three-dimensional representation for any structure available on PDB. We envisage these techniques to be useful for students when visualizing simple stereochemical problems or complex pathway interactions.

Case study: Perspectives on the use of LEGO® bricks in the biochemistry classroom.

The use of LEGO® bricks in the higher education classroom has increased in the last two decades. This is no different in the STEM classroom and several disciplines, including physics, chemistry, and biology, have all made use of LEGO® bricks in some way to create models for active learning activities. Currently, the discipline to make the greatest use of LEGO® bricks is chemistry; only limited examples exist in biochemistry and the molecular life sciences. Here, we present the use of a LEGO® brick modelling activity in the introductory biochemistry classroom during the teaching of metabolism. We present student comments on the activity and the models that were generated by the students. Additionally, we focus on other instructor and project student-designed models for the teaching of ATP synthesis, gene regulation and restriction digestion. Interestingly, both the gene regulation and restriction digest activities were generated with the help of undergraduate students or recent graduates, by applying a backward design approach. This case study seeks to encourage more molecular life science educators to adopt the use of LEGO® bricks in their classrooms to engage in more active learning.

Utilization of EKOS in Patients With Pulmonary Embolism.

Objective: Current guidelines recommend utilization of catheter-directed thrombolysis systems for management of patients with submassive pulmonary embolism (PE) who have relative contraindications to systemic thrombolysis. Evidence from previous trials have demonstrated the short-term efficacy and safety of one of these systems, the EkoSonic Endovascular System (EKOS). The objective of this study was to evaluate the long-term efficacy and safety of EKOS in submassive PE. Methods: This single-center, retrospective study evaluated subjects ≥18 years old with submassive PE and baseline right ventricular to left ventricular (RV/LV) diameter ratio ≥1. The primary outcome evaluated change in RV/LV diameter ratio from baseline to first follow-up. The secondary outcomes evaluated need for further intervention after EKOS, major bleeding within 72 hours and 6 months, all-cause mortality at 6 months, and all-cause 30-day readmission rate. Results: Overall, 41 subjects received EKOS for submassive PE. Of the 26 subjects evaluated for the primary outcome, the RV/LV diameter ratio decreased by an average of 0.56 (P < 0.05). Of the 41 subjects evaluated for the secondary outcomes, 1 subject required pulmonary embolectomy after EKOS intervention, 1 major bleed occurred within 72 hours, 1 major bleed occurred within 6 months, 1 subject died within 6 months, and 3 subjects were readmitted within 30 days. Conclusions: Intervention with EKOS further reduced right heart strain and resulted in few complications compared with previous trials providing evidence that EKOS is effective and safe long-term for management of submassive PE. Use should be considered in patients with relative contraindications to systemic thrombolytic therapy.

Mitochondrial osmoregulation in evolution, cation transport and metabolism.

This review provides a retrospective on the role of osmotic regulation in the process of eukaryogenesis. Specifically, it focuses on the adjustments which must have been made by the original colonizing α-proteobacteria that led to the evolution of modern mitochondria. We focus on the cations that are fundamentally involved in volume determination and cellular metabolism and define the transporter landscape in relation to these ions in mitochondria as we know today. We provide analysis on how the cations interplay and together maintain osmotic balance that allows for effective ATP synthesis in the organelle.

Highly Sensitive Virome Characterization of Aedes aegypti and Culex pipiens Complex from Central Europe and the Caribbean Reveals Potential for Interspecies Viral Transmission.

Mosquitoes are the most important vectors for arthropod-borne viral diseases. Mixed viral infections of mosquitoes allow genetic recombination or reassortment of diverse viruses, turning mosquitoes into potential virologic mixing bowls. In this study, we field-collected mosquitoes of different species (Aedes aegypti and Culex pipiens complex), from different geographic locations and environments (central Europe and the Caribbean) for highly sensitive next-generation sequencing-based virome characterization. We found a rich virus community associated with a great diversity of host species. Among those, we detected a large diversity of novel virus sequences that we could predominately assign to circular Rep-encoding single-stranded (CRESS) DNA viruses, including the full-length genome of a yet undescribed Gemykrogvirus species. Moreover, we report for the first time the detection of a potentially zoonotic CRESS-DNA virus (Cyclovirus VN) in mosquito vectors. This study expands the knowledge on virus diversity in medically important mosquito vectors, especially for CRESS-DNA viruses that have previously been shown to easily recombine and jump the species barrier.

Integrating CRISPR-Cas9 Technology into Undergraduate Courses: Perspectives from a National Science Foundation (NSF) Workshop for Undergraduate Faculty, June 2018.

As CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 technology becomes more mainstream in life science research, it becomes critical for undergraduate instructors to devise engaging ways to bring the technology into their classrooms. To help meet this challenge, the National Science Foundation sponsored a workshop for undergraduate instructors in June 2018 at The Ohio State University in conjunction with the annual Association of Biology Laboratory Educators meeting based on a workflow developed by the workshop's facilitators. Over the course of two and a half days, participants worked through a modular workflow for the use of CRISPR-Cas9 in a course-based (undergraduate) research experience (CURE) setting while discussing the barriers each of their institutions had to implementing such work, and how such barriers could be overcome. The result of the workshop was a team with newfound energy and confidence to implement CRISPR-Cas9 technology in their courses and the development of a community of undergraduate educators dedicated to supporting each other in the implementation of the workflow either in a CURE or modular format. In this article, we review the activities and discussions from the workshop that helped each participant devise their own tailored approaches of how best to bring this exciting new technology into their classes.

LETM1-Mediated K+ and Na+ Homeostasis Regulates Mitochondrial Ca2+ Efflux.

Ca2+ transport across the inner membrane of mitochondria (IMM) is of major importance for their functions in bioenergetics, cell death and signaling. It is therefore tightly regulated. It has been recently proposed that LETM1­an IMM protein with a crucial role in mitochondrial K+/H+ exchange and volume homeostasis­also acts as a Ca2+/H+ exchanger. Here we show for the first time that lowering LETM1 gene expression by shRNA hampers mitochondrial K+/H+ and Na+/H+ exchange. Decreased exchange activity resulted in matrix K+ accumulation in these mitochondria. Furthermore, LETM1 depletion selectively decreased Na+/Ca2+ exchange mediated by NCLX, as observed in the presence of ruthenium red, a blocker of the Mitochondrial Ca2+ Uniporter (MCU). These data confirm a key role of LETM1 in monovalent cation homeostasis, and suggest that the effects of its modulation on mitochondrial transmembrane Ca2+ fluxes may reflect those on Na+/H+ exchange activity.

Novel p53-dependent anticancer strategy by targeting iron signaling and BNIP3L-induced mitophagy.

This study identifies BNIP3L as the key regulator of p53-dependent cell death mechanism in colon cancer cells targeted by the novel gallium based anticancer drug, KP46. KP46 specifically accumulated into mitochondria where it caused p53-dependent morphological and functional damage impairing mitochondrial dynamics and bioenergetics. Furthermore, competing with iron for cellular uptake, KP46 lowered the intracellular labile iron pools and intracellular heme. Accordingly, p53 accumulated in the nucleus where it activated its transcriptional target BNIP3L, a BH3 only domain protein with functions in apoptosis and mitophagy. Upregulated BNIP3L sensitized the mitochondrial permeability transition and strongly induced PARKIN-mediated mitochondrial clearance and cellular vacuolization. Downregulation of BNIP3L entirely rescued cell viability caused by exposure of KP46 for 24 hours, confirming that early induced cell death was regulated by BNIP3L. Altogether, targeting BNIP3L in wild-type p53 colon cancer cells is a novel anticancer strategy activating iron depletion signaling and the mitophagy-related cell death pathway.

Distribution of CYP17α polymorphism and selected physiochemical factors of uterine leiomyoma in Barbados.

Uterine leiomyoma is a major reproductive health disease among women and in particular Black women. The present study sought to determine whether a single nucleotide polymorphism (SNP) of CYP17 (rs743572) was associated with the risk of developing uterine leiomyoma (UL) in affected women in Barbados; a majority Black population. It also sought to determine if BMI, waist circumference and oestradiol levels were associated with UL in this group. A total of 96 random persons were assessed in a case-control study using a PCR-RFLP assay, and measurements of body mass index, waist circumference, and oestradiol levels were also assessed. Our results showed no genetic association with the risk of UL and this gene. The genetic distribution of CYP 17α- alleles resembled a normal Hardy-Weinberg distribution, and a relatively low risk of 0.25 at a confidence interval at 95%, of UL disease development. However, a significant association was found between oestradiol levels and fibroids, as well as oestradiol levels and BMI, at P < 0.05 among cases. Therefore our study indicates that significant associations between physiochemical factors comprising BMI, waist circumference, and oestrogen levels are disease indicators in this population. In conclusion, our findings suggest that obesity and its associated risk factors are important in a majority Black Caribbean population, although the sample size needs to be increased.

Carbon source and myc expression influence the antiproliferative actions of metformin.

Epidemiologic and experimental data have led to increased interest in possible roles of biguanides in cancer prevention and/or treatment. Prior studies suggest that the primary action of metformin is inhibition of oxidative phosphorylation, resulting in reduced mitochondrial ATP production and activation of AMPK. In vitro, this may lead to AMPK-dependent growth inhibition if AMPK and its effector pathways are intact or to an energetic crisis if these are defective. We now show that the effect of exposure of several transformed cell lines to metformin varies with carbon source: in the presence of glutamine and absence of glucose, a 75% decrease in cellular ATP and an 80% decrease in cell number is typical; in contrast, when glucose is present, metformin exposure leads to increased glycolysis, with only a modest reduction in ATP level and cell number. Overexpression of myc was associated with sensitization to the antiproliferative effects of metformin, consistent with myc involvement in "glutamine addiction". Our results reveal previously unrecognized factors that influence metformin sensitivity and suggest that metformin-induced increase in glycolysis attenuates the antiproliferative effects of the compound.

Impact of PGC-1α on the topology and rate of superoxide production by the mitochondrial electron transport chain.

Reactive oxygen species (ROS) play an important role in normal signaling events and excessive ROS are associated with many pathological conditions. The amount of ROS in cells is dependent on both the production of ROS by the mitochondrial electron transport chain and their removal by ROS-detoxifying enzymes. The peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is a master regulator of mitochondrial functions and a key regulator of the ROS-detoxifying program. However, the impact of PGC-1α on the topology and rate of superoxide production by the mitochondrial electron transport chain is not known. We report here, using mitochondria from muscle creatine kinase-PGC-1α transgenic mice, that PGC-1α does not affect the topology of ROS production, but increases the capacity of complexes I and III to generate ROS. These changes are associated with increased mitochondrial respiration and content of respiratory chain complexes. When normalizing ROS production to mitochondrial respiration, we find that PGC-1α preserves the percentage of free radical leak by the electron transport chain. Together, these data demonstrate that PGC-1α regulates the intrinsic properties of mitochondria in such a way as to preserve a tight coupling between mitochondrial respiration and ROS production.