The ABA-LANCL1/2 Hormone-Receptors System Protects H9c2 Cardiomyocytes from Hypoxia-Induced Mitochondrial Injury via an AMPK- and NO-Mediated Mechanism

Nuclear transport of phosphorylated LanCL2 promotes invadopodia formation and tumor progression of glioblastoma by activating STAT3/Cortactin signaling

INTRODUCTION

Our previous study showed that the abscisic acid receptor lanthionine synthetase C-like 2 (LanCL2) is a significant prognostic factor for overall survival in young glioblastoma patients. However, the role of LanCL2 in glioblastoma remains unclear yet.

OBJECTIVES

This study aims to investigate the role of LanCL2 in regulating in-vitro cell invasion and in-vivo tumor progression of glioblastoma and its underlying mechanism.

METHODS

Tyrosine 198 or 295 residue of LanCL2 was mutated using site-directed mutagenesis to block its phosphorylation. The role of LanCL2 in glioblastoma was investigated using transwell or 3D invasion assay, matrix degradation assay and intracranial xenograft model.

RESULTS

This study showed that nuclear transport of LanCL2 was enhanced by overexpression of LanCL2 or its ligand abscisic acid in glioblastoma cells. Knockdown of LanCL2 suppressed migration, invasion and invadopodia formation of glioblastoma cells, whereas overexpression of wild-type LanCL2 enhanced them. Blocking of Tyr295 residue phosphorylation of LanCL2 impeded its nuclear transport, retarded glioblastoma cell motility and invadopodia formation, and deceased the phosphorylation of Cortactin and STAT3. c-Met was identified as the upstream tyrosine kinase of Tyr295 residue of LanCL2, and inhibition of c-Met markedly suppressed the nuclear transport of LanCL2. Moreover, overexpression of wild-type LanCL2 significantly promoted orthotopic tumor growth of glioblastoma in vivo and led to poor survival of mice with median survival time of 33.5 days, whereas Tyr295 mutation rescued it with median survival time of 49 days.

CONCLUSION

Our findings suggested that Tyr295 phosphorylation is crucial to the activation and nuclear transport of LanCL2, as well as invadopodia formation and tumor progression of glioblastoma, providing the evidence of a novel signaling axis c-Met/LanCL2/STAT3/Cortactin and the first observation of the importance of Tyr295 phosphorylation to LanCL2.

Electrochemical sensing of transient ascorbate fluctuation under hypoxic stress in live rat brain

Hypoxia, a common cause of programmed cell death or apoptosis, represents a neuropathological process. Although certain response proteins to hypoxic stress and their effects on cell status and fate have been identified, the real-time quantification of smaller neurochemicals to understand pathogenic mechanism in live rat brain during such stress remains unexplored. In this study, by employing a cutting-edge electrochemical tool developed with carbon nanotube-sheathed carbon fiber microelectrode that offers remarkable selectivity and temporal/spatial resolution for monitoring ascorbate, we observed a substantial efflux of ascorbate in response to hypoxic stress in live rat brain. Furthermore, using a small molecule compound as channel inhibitor to investigate the behavior of ascorbate efflux, we found that this efflux is closely correlated with N-methyl-D-aspartic acid receptor-induced neuronal excitability. Notably, antagonistic actions on volume-sensitive anion channel can suppress ascorbate efflux evoked by hypoxic stress, further revealing that ascorbate fluctuation is volume-sensitive anion channel-dependent. This research not only facilitates a greater understanding of the neurochemical mechanism in hypoxia but also uncovers a potential biomarker for future closed-loop therapies.

Role of Abscisic Acid in the Whole-Body Regulation of Glucose Uptake and Metabolism

Abscisic acid (ABA) is a hormone with a long evolutionary history, dating back to the earliest living organisms, of which modern (ABA-producing) cyanobacteria are likely descendants, which existed long before the separation of the plant and animal kingdoms, with a conserved role as signals regulating cell responses to environmental challenges. In mammals, along with the anti-inflammatory and neuroprotective function of ABA, nanomolar ABA regulates the metabolic response to glucose availability by stimulating glucose uptake in skeletal muscle and adipose tissue via an insulin-independent mechanism and increasing metabolic energy production and also dissipation in brown and white adipocytes. Chronic ABA intake of micrograms per Kg body weight improves blood glucose, lipids, and morphometric parameters (waist circumference and body mass index) in borderline subjects for prediabetes and metabolic syndrome. This review summarizes the most recent in vitro and in vivo data obtained with nanomolar ABA, the involvement of the receptors LANCL1 and LANCL2 in the hormone's action, and the importance of mammals' endowment with two distinct hormones governing the metabolic response to glucose availability. Finally, unresolved issues and future directions for the clinical use of ABA in diabetes are discussed.

Thermal measurements support a role of the ABA/LANCL1-2 hormone/receptors system in thermogenesis

Abscisic acid (ABA) is a conserved 'stress hormone' in unicellular organisms, plants and animals. In mammals, ABA and its receptors LANCL1 and LANCL2 stimulate insulin-independent cell glucose uptake and oxidative metabolism: overexpression of LANCL1/2 increases, and their silencing conversely reduces, mitochondrial number, respiration and proton gradient dissipation in muscle cells and in brown adipocytes. We hypothesized that the ABA/LANCL hormone/receptors system could be involved in thermogenesis. Heat production by LANCL1/2-overexpressing versus double-silenced cells was compared in rat H9c2 cardiomyocytes with two different methods: differential temperature measurements using sensitive thermistor probes and differential isothermal calorimetry. Overexpressing cells generate an approximately double amount of thermal power compared with double-silenced cells, and addition of ABA further doubles heat production in overexpressing cells. With the temperature probes, we find a timescale of approximately 4 min for thermogenesis to 'turn on' after nutrient addition. We provide direct measurements of increased heat production triggered by the ABA/LANCL hormone receptors system. Combined with previous work on oxphos decoupling, these results support the role of the ABA/LANCL hormone receptors system as a hitherto unknown regulator of cell thermogenesis.

Immunometabolic Mechanisms of LANCL2 in CD4+ T Cells and Phagocytes Provide Protection from Systemic Lupus Erythematosus

Lanthionine synthetase C-like 2 (LANCL2) is an immunoregulatory therapeutic target for autoimmune diseases. NIM-1324 is an investigational new drug aimed at addressing the unmet clinical needs of patients with systemic lupus erythematosus (SLE) by targeting the LANCL2 immunometabolic pathway. In R848 and bm12 adoptive transfer models of systemic inflammation that share pathologies with SLE, Lancl2-/- mice experienced greater mortality, increased spleen weight, and reduced CD25hi FOXP3+ CD4+ regulatory T cells compared with the wild type. Conversely, treatment with NIM-1324 in the wild type increased CD25hi FOXP3+ regulatory T cells while reducing inflammatory IL-17+ and IL-21+ CD4+ T cell subsets in the spleen. In traditional mouse models of SLE (NZB/W F1 and MRL/lpr), oral treatment with NIM-1324 protected against weight loss and proteinuria, decreased anti-dsDNA titers, and provided similar changes to the CD4+ T cell compartment in the spleen. The pharmacological activation of LANCL2 by NIM-1324 rescued hypocomplementemia, reduced kidney histopathological scores, and decreased blood IFN response genes and inflammatory cytokines. The loss of LANCL2 in phagocytes impairs phagosome processing, leading to increased uptake of material and inflammatory cytokine production, yet decreased markers of endosomal maturation, phagosome turnover, and lysozyme activity. Treatment with NIM-1324 increases metabolic and lysozyme activity in the phagosome, providing support for increased markers of early phagosome function. This efficacy translated to human PBMCs from patients with SLE, because ex vivo treatment with NIM-1324 resulted in reduced levels of IFN-α, IL-6, and IL-8. Consequently, the activation of LANCL2 effectively modulates CD4+ T cell differentiation and phagocyte activation, supporting immune tolerance in SLE.

LanCL1 protects developing neurons from long-term isoflurane anesthesia-induced neurotoxicity

Research has revealed that prolonged or repeated exposure to isoflurane, a common general anesthetic, can lead to cognitive and behavioral deficiencies, particularly in early life. The brain contains a wealth of LanCL1, an antioxidant enzyme that is thought to mitigate oxidative stress. Nevertheless, its precise function in mammals remains uncertain. This study uncovered a decrease in the expression of LanCL1 due to prolonged isoflurane anesthesia, accompanied by anesthesia-induced neurotoxicity in vivo and in vitro. To better understand LanCL1's essential function, LanCL1 overexpressing adenoviruses were employed to increase LanCL1 levels. The outcomes were analyzed using western blot and immunofluorescence methods. According to the findings, extended exposure to isoflurane anesthesia may lead to developmental neurotoxicity in vivo and in vitro. The anesthesia-induced neurotoxicity was concomitant with a reduction in LanCL1 expression. Moreover, the study revealed that overexpression of LanCL1 can mitigate the neurotoxic effects of isoflurane anesthesia, resulting in improved synaptic growth, less reactive oxygen species, enhanced cell viability and rescued memory deficits in the developing brain. In conclusion, prolonged anesthesia-induced LanCL1 deficiency could be responsible for neurotoxicity and subsequent cognitive impairments in the developing brain. Additional LanCL1 counteracts this neurotoxic effect and protects neurons from long-term isoflurane anesthesia.

Abscisic acid, an evolutionary conserved hormone: Biosynthesis, therapeutic and diagnostic applications in mammals

Abscisic acid (ABA), a phytohormone traditionally recognized for its role in plant stress responses, has recently emerged as a significant player in mammalian defense mechanisms. Like plants, various mammalian cell types synthesize ABA in response to specific health challenges, although the precise pathways remain not fully elucidated. ABA is associated with the regulation of inflammation and insulin signaling, prompting extensive research into its potential as a therapeutic agent for various diseases. ABA exerts its effects through its receptors, particularly PPAR-γ and LANCL-2, which serve as signaling hubs regulating numerous pathways. Through these interactions, ABA profoundly impacts mammalian health, and new ABA targets continue to be identified. Numerous studies in animal models demonstrate ABA's benefit in managing conditions such as neurological and psychiatric disorders, cancer, and malaria infections, all of which involve significant inflammatory dysregulation. In this manuscript we review the studies covering ABA synthesis and release in cell cultures, the signaling pathways regulated by ABA, and how these impact health in preclinical models. Furthermore, we highlight recent research suggesting that measuring ABA levels in human body fluids could serve as a useful biomarker for pathological conditions, providing insights into disease progression and treatment efficacy. This comprehensive review outlines the current understanding of ABA in mammalian pathophysiology, identifying gaps in knowledge, particularly concerning ABA biosynthesis and metabolism in mammals. In addition, this study emphasizes the need for clinical trials to validate the effectiveness of ABA-based therapies and its reliability as a biomarker for various diseases.

The ABA/LANCL1-2 Hormone/Receptors System Controls ROS Production in Cardiomyocytes through ERRα

Rat H9c2 cardiomyocytes overexpressing the abscisic acid (ABA) hormone receptors LANCL1 and LANCL2 have an increased mitochondrial proton gradient, respiration, and vitality after hypoxia/reoxygenation. Our aim was to investigate the role of the ABA/LANCL1-2 system in ROS turnover in H9c2 cells. H9c2 cells were retrovirally infected to induce the overexpression or silencing of LANCL1 and LANCL2, without or with the concomitant silencing of the transcription factor ERRα. Enzymes involved in radical production or scavenging were studied by qRT-PCR and Western blot. The mitochondrial proton gradient and ROS were measured with specific fluorescent probes. ROS-generating enzymes decreased, ROS-scavenging enzymes increased, and mitochondrial ROS were reduced in LANCL1/2-overexpressing vs. control cells infected with the empty vector, while the opposite occurred in LANCL1/2-silenced cells. The knockdown of ERRα abrogated all beneficial effects on ROS turnover in LANCL1/2 overexpressing cells. Taken together, these results indicate that the ABA/LANCL1-2 system controls ROS turnover in H9c2 via ERRα. The ABA/LANCL system emerges as a promising target to improve cardiomyocyte mitochondrial function and resilience to oxidative stress.

Distinct phenotypes induced by acute hypoxia and TGF-β1 in human adult cardiac fibroblasts

Myocardial infarction (MI) causes hypoxic injury to downstream myocardial tissue, which initiates a wound healing response that replaces injured myocardial tissue with a scar. Wound healing is a complex process that consists of multiple phases, in which many different stimuli induce cardiac fibroblasts to differentiate into myofibroblasts and deposit new matrix. While this process is necessary to replace necrotic tissue, excessive and unresolved fibrosis is common post-MI and correlated with heart failure. Therefore, defining how cardiac fibroblast phenotypes are distinctly regulated by stimuli that are prevalent in the post-MI microenvironment, such as hypoxia and transforming growth factor-beta (TGF-β), is essential for understanding and ultimately mitigating pathological fibrosis. In this study, we acutely treated primary human adult cardiac fibroblasts with TGF-β1 or hypoxia and then characterized their phenotype through immunofluorescence, quantitative RT-PCR, and proteomic analysis. We found that fibroblasts responded to low oxygen with increased localization of hypoxia inducible factor 1 (HIF-1) to the nuclei after 4h, which was followed by increased gene expression of vascular endothelial growth factor A (VEGFA), a known target of HIF-1, by 24h. Both TGF-β1 and hypoxia inhibited proliferation after 24h. TGF-β1 treatment also upregulated various fibrotic pathways. In contrast, hypoxia caused a reduction in several protein synthesis pathways, including collagen biosynthesis. Collectively, these data suggest that TGF-β1, but not acute hypoxia, robustly induces the differentiation of human cardiac fibroblasts into myofibroblasts. Discerning the overlapping and distinctive outcomes of TGF-β1 and hypoxia treatment is important for elucidating their roles in fibrotic remodeling post-MI and provides insight into potential therapeutic targets.

Genome-Wide Identification and Expression Analysis of GATA Family Genes in Dimocarpus longan Lour

GATA transcription factors, which are DNA-binding proteins with type IV zinc finger binding domains, have a role in transcriptional regulation in biological organisms. They have an indispensable role in the growth and development of plants, as well as in improvements in their ability to face various environmental stresses. To date, GATAs have been identified in many gene families, but the GATA gene in longan (Dimocarpus longan Lour) has not been studied in previous explorations. Various aspects of genes in the longan GATA family, including their identification and classification, the distribution of their positions on chromosomes, their exon/intron structures, a synteny analysis, their expression at different temperatures, concentration of PEG, early developmental stages of somatic embryos and their expression levels in different tissues, and concentrations of exogenous hormones, were investigated in this study. This study showed that the 22 DlGATAs could be divided into four subfamilies. There were 10 pairs of homologous GATA genes in the synteny analysis of DlGATA and AtGATA. Four segmental replication motifs and one pair of tandem duplication events were present among the DlGATA family members. The cis-acting elements located in promoter regions were also found to be enriched with light-responsive elements, which contained related hormone-responsive elements. In somatic embryos, DlGATA4 is upregulated for expression at the globular embryo (GE) stage. We also found that DlGATA expression was strongly up-regulated in roots and stems. The study demonstrated the expression of DlGATA under hormone (ABA and IAA) treatments in embryogenic callus of longan. Under ABA treatment, DlGATA4 was up-regulated and the other DlGATA genes did not respond significantly. Moreover, as demonstrated with qRT-PCR, the expression of DlGATA genes showed strong up-regulated expression levels under 100 μmol·L-1 concentration IAA treatment. This experiment further studied these and simulated their possible connections with a drought response mechanism, while correlating them with their expression under PEG treatment. Overall, this experiment explored the GATA genes and dug into their evolution, structure, function, and expression profile, thus providing more information for a more in-depth study of the characteristics of the GATA family of genes.

New Insights into the LANCL2- Binding Mode towards the Evaluation of New LANCL Agonists

The lanthionine synthetase C-like (LANCL) proteins include LANCL2, which is expressed in the central nervous system (CNS) and in peripheral tissues. LANCL2 exhibits glutathionylation activity and is involved in the neutralization of reactive electrophiles. Several studies explored LANCL2 activation as a validated pharmacological target for diabetes and inflammatory bowel disease. In this context, LANCL2 was found to bind the natural product abscisic acid (ABA), whose pre-clinical effectiveness in different inflammatory diseases was reported in the literature. More recently, LANCL2 attracted more attention as a valuable resource in the field of neurodegenerative disorders. ABA was found to regulate neuro-inflammation and synaptic plasticity to enhance learning and memory, exhibiting promising neuroprotective effects. Up until now, a limited number of LANCL2 ligands are known; among them, BT-11 is the only compound patented and investigated for its anti-inflammatory properties. To guide the design of novel putative LANCL2 agonists, a computational study including molecular docking and long molecular dynamic (MD) simulations of both ABA and BT-11 was carried out. The results pointed out the main LANCL2 ligand chemical features towards the following virtual screening of a novel putative LANCL2 agonist (AR-42). Biochemical assays on rat H9c2 cardiomyocytes showed a similar, LANCL2-mediated stimulation by BT-11 and by AR-42 of the mitochondrial proton gradient and of the transcriptional activation of the AMPK/PGC-1α/Sirt1 axis, the master regulator of mitochondrial function, effects that are previously observed with ABA. These results may allow the development of LANCL2 agonists for the treatment of mitochondrial dysfunction, a common feature of chronic and degenerative diseases.

Evaluation of a large-scale aptamer proteomics platform among patients with kidney failure on dialysis

BACKGROUND

Patients with kidney failure suffer high mortality, and we currently lack markers for risk stratification for these patients. We carried out a quality control study of a modified aptamer assay (SomaScan v.4.0) that measures ~ 5000 proteins, in preparation for a larger study using this platform in cohorts with kidney failure.

METHODS

Forty participants from the Cardiac, Endothelial Function and Arterial Stiffness in End-Stage Renal Disease (CERES study) were selected to analyze technical and short-term biological variability, orthogonal correlations and differential protein expression in plasma from patients who died during 2.5 year follow-up. Long-term (one year) variability was studied in 421 participants in the Chronic Renal Insufficiency Cohort. We evaluated 4849 aptamers (4607 unique proteins) using data formats including raw data and data formatted using Adaptive Normalization by Maximum Likelihood (ANML), an algorithm developed for SomaScan data in individuals with normal kidney function.

RESULTS

In ANML format, median[IQR] intra-assay coefficient of variation (CV) was 2.38%[1.76, 3.40] and inter-assay CV was 7.38%[4.61, 13.12]. Short-term within-subject CV was 5.76% [3.35, 9.72]; long-term CV was 8.71%[5.91, 13.37]. Spearman correlations between aptamer and traditional assays for PTH, NT-proBNP, FGF-23 and CRP were all > 0.7. Fold-change (FC) in protein levels among non-survivors, significant after Bonferroni correction, included SVEP1 (FC[95% CI] 2.14 [1.62, 2.82]), keratocan (1.74 [1.40, 2.15]) and LanC-like protein 1 (0.56 [0.45, 0.70]). Compared to raw aptamer data, technical and short-term biological variability in paired samples was lower in ANML-formatted data. ANML formatting had minimal impact on orthogonal correlations with traditional assays or the associations of proteins with the phenotype of mortality.

CONCLUSIONS

SomaScan had excellent technical variability and low within-subject short-term variability. ANML formatting could facilitate comparison of biomarker results with other studies that utilize this format. We expect SomaScan to provide novel and reproducible information in patients with kidney failure on dialysis.

Abscisic Acid and Its Receptors LANCL1 and LANCL2 Control Cardiomyocyte Mitochondrial Function, Expression of Contractile, Cytoskeletal and Ion Channel Proteins and Cell Proliferation via ERRα

The cross-kingdom stress hormone abscisic acid (ABA) and its mammalian receptors LANCL1 and LANCL2 regulate the response of cardiomyocytes to hypoxia by activating NO generation. The overexpression of LANCL1/2 increases transcription, phosphorylation and the activity of eNOS and improves cell vitality after hypoxia/reoxygenation via the AMPK/PGC-1α axis. Here, we investigated whether the ABA/LANCL system also affects the mitochondrial oxidative metabolism and structural proteins. Mitochondrial function, cell cycle and the expression of cytoskeletal, contractile and ion channel proteins were studied in H9c2 rat cardiomyoblasts overexpressing or silenced by LANCL1 and LANCL2, with or without ABA. Overexpression of LANCL1/2 significantly increased, while silencing conversely reduced the mitochondrial number, OXPHOS complex I, proton gradient, glucose and palmitate-dependent respiration, transcription of uncoupling proteins, expression of proteins involved in cytoskeletal, contractile and electrical functions. These effects, and LANCL1/2-dependent NO generation, are mediated by transcription factor ERRα, upstream of the AMPK/PGC1-α axis and transcriptionally controlled by the LANCL1/2-ABA system. The ABA-LANCL1/2 hormone-receptor system controls fundamental aspects of cardiomyocyte physiology via an ERRα/AMPK/PGC-1α signaling axis and ABA-mediated targeting of this axis could improve cardiac function and resilience to hypoxic and dysmetabolic conditions.

The ameliorative effects and mechanisms of abscisic acid on learning and memory

Abscisic acid (ABA), a conserved hormone existing in plants and animals, not only regulates blood glucose and inflammation but also has good therapeutic effects on obesity, diabetes, atherosclerosis and inflammatory diseases in animals. Studies have shown that exogenous ABA can pass the blood-brain barrier and inhibit neuroinflammation, promote neurogenesis, enhance synaptic plasticity, improve learning, memory and cognitive ability in the central nervous system. At the same time, ABA plays a crucial role in significant improvement of Alzheimer's disease, depression, and anxiety. Here we review the previous research progress of ABA on the physiological effects and clinical application in the related diseases. By summarizing the biological functions of ABA, we aim to reveal the possible mechanisms of ameliorative function of ABA on learning and memory, to provide a theoretical basis that ABA as a novel and safe drug improves learning memory and cognitive impairment in central system diseases such as aging, neurodegenerative diseases and traumatic brain injury.

The ABA/LANCL1/2 Hormone/Receptor System Controls Adipocyte Browning and Energy Expenditure

The abscisic acid (ABA)/LANC-like protein 1/2 (LANCL1/2) hormone/receptor system regulates glucose uptake and oxidation, mitochondrial respiration, and proton gradient dissipation in myocytes. Oral ABA increases glucose uptake and the transcription of adipocyte browning-related genes in rodent brown adipose tissue (BAT). The aim of this study was to investigate the role of the ABA/LANCL system in human white and brown adipocyte thermogenesis. Immortalized human white and brown preadipocytes, virally infected to overexpress or silence LANCL1/2, were differentiated in vitro with or without ABA, and transcriptional and metabolic targets critical for thermogenesis were explored. The overexpression of LANCL1/2 increases, and their combined silencing conversely reduces mitochondrial number, basal, and maximal respiration rates; proton gradient dissipation; and the transcription of uncoupling genes and of receptors for thyroid and adrenergic hormones, both in brown and in white adipocytes. The transcriptional enhancement of receptors for browning hormones also occurs in BAT from ABA-treated mice, lacking LANCL2 but overexpressing LANCL1. The signaling pathway downstream of the ABA/LANCL system includes AMPK, PGC-1α, Sirt1, and the transcription factor ERRα. The ABA/LANCL system controls human brown and "beige" adipocyte thermogenesis, acting upstream of a key signaling pathway regulating energy metabolism, mitochondrial function, and thermogenesis.

The ABA/LANCL Hormone/Receptor System in the Control of Glycemia, of Cardiomyocyte Energy Metabolism, and in Neuroprotection: A New Ally in the Treatment of Diabetes Mellitus?

Abscisic acid (ABA), long known as a plant stress hormone, is present and functionally active in organisms other than those pertaining to the land plant kingdom, including cyanobacteria, fungi, algae, protozoan parasites, lower Metazoa, and mammals. The ancient, cross-kingdom role of this stress hormone allows ABA and its signaling pathway to control cell responses to environmental stimuli in diverse organisms such as marine sponges, higher plants, and humans. Recent advances in our knowledge about the physiological role of ABA and of its mammalian receptors in the control of energy metabolism and mitochondrial function in myocytes, adipocytes, and neuronal cells allow us to foresee therapeutic applications for ABA in the fields of pre-diabetes, diabetes, and cardio- and neuro-protection. Vegetal extracts titrated in their ABA content have shown both efficacy and tolerability in preliminary clinical studies. As the prevalence of glucose intolerance, diabetes, and cardiovascular and neurodegenerative diseases is steadily increasing in both industrialized and rapidly developing countries, new and cost-efficient therapeutics to combat these ailments are much needed to ensure disease-free aging for the current and future working generations.

Identification of miRNAs as Biomarkers of Cardiac Protection in Non-Genetically Modified Primary Human Cardiomyocytes Exposed to Halogenated Hypnotics in an In Vitro Model of Transfection and Ischemia/Reperfusion: A New Model in Translational Anesthesia

BACKGROUND

Many clinical studies have identified some circulating micro-RNAs (miRNAs) as potential biomarkers with regard to the cardioprotective effects of halogenated agents administered perioperatively during myocardial conditioning procedures. However, there is a major methodological difficulty in identifying these potential miRNA targets in cardiac cells.

METHODS

We developed an in vitro protocol to analyze the differential expression of target miRNAs at the intracellular level in non-genetically modified primary human cardiomyocytes (HCMs) through their exposure to different hypnotic compounds (i.e., halogenated versus non-halogenated). For this purpose, we performed a validated in vitro model of "ischemia and reperfusion" with the transfection of specific miRNA mimics (MIMICs) designed to simulate naturally occurring mature miRNAs as a functional study. Afterwards, next-generation sequencing (NGS) was used to identify and quantify miRNAs and elucidate their function. The differences in miRNA expression between HCMs exposed to different hypnotic drugs, along with the prediction of functional miRNA targets, were assessed using a meticulous in-house bioinformatics pipeline in order to derive diagnostic biomarkers and possible therapeutic targets.

CONCLUSION

In brief, this methodological procedure was designed to investigate whether the cardioprotective effects of halogenated agents are a phenomenon mediated by either the activation or the suppression of miRNAs targeted by halogenated anesthetics.

Amino acid motifs for the identification of novel protein interactants

Biological systems consist of multiple components of different physical and chemical properties that require complex and dynamic regulatory loops to function efficiently. The discovery of ever more novel interacting sites in complex proteins suggests that we are only beginning to understand how cellular and biological functions are integrated and tuned at the molecular and systems levels. Here we review recently discovered interacting sites which have been identified through rationally designed amino acid motifs diagnostic for specific molecular functions, including enzymatic activities and ligand-binding properties. We specifically discuss the nature of the latter using as examples, novel hormone recognition and gas sensing sites that occur in moonlighting protein complexes. Drawing evidence from the current literature, we discuss the potential implications at the cellular, tissue, and/or organismal levels of such non-catalytic interacting sites and provide several promising avenues for the expansion of amino acid motif searches to discover hitherto unknown protein interactants and interaction networks. We believe this knowledge will unearth unexpected functions in both new and well-characterized proteins, thus filling existing conceptual gaps or opening new avenues for applications either as drug targets or tools in pharmacology, cell biology and bio-catalysis. Beyond this, motif searches may also support the design of novel, effective and sustainable approaches to crop improvements and the development of new therapeutics.