Highly enhanced removal of Cr(VI) by nZVI in presence of myo-inositol hexakisphosphate: The depassivation performance and multiple electron transfer mechanisms.

The capability of traditional ligand in countering rapid passivation on nanoscale zero-valent iron (nZVI) surface is inadequate, and the precise electron transfer mechanism remains elusive. In this study, we reported that myo-inositol hexakisphosphate (IHP), a redox-inactive organophosphorus in soil, could highly enhance Cr(VI) reduction and immobilization in comparison with typical ligands (TPP, EDTA, oxalate and phosphate). And the effects of IHP concentration, Cr(VI) concentration and initial pH were systematically investigated. Cr K-edge XANES and XPS analysis revealed that Cr(III) was the exclusive form in solid products regardless of IHP existence. Results of ATR-FTIR and FESEM inferred that IHP was adsorbed on nZVI surface via inner-sphere complexation, thus averting encapsulation of [Fe, Cr](OH)3 coprecipitate and impeding solid particles agglomeration. Additionally, IHP expedited the production of surface-bound Fe(II), primarily attributable to the interaction between nZVI and oxygen. These surface-bound Fe(II) species played a pivotal role in Cr(VI) reduction. Electrochemical analysis unveiled that IHP lowered redox potential of Fe(III)/Fe(II), thereby facilitating reaction between Fe(II) and Cr(VI), whereas inhibited direct electron transfer from nZVI core to Cr(VI). Our findings proposed a novel potential ligand for alleviating nZVI passivation in Cr(VI) removal and deepened our understanding in the process of electron transfer.

Quantifying Gq Signaling Using the IP1 Homogenous Time-Resolved Fluorescence (HTRF) Assay.

G protein-coupled receptors (GPCRs) play pivotal roles in cellular signaling and can regulate several cellular functions such as proliferation, secretion, protein expression, and cellular metabolism. Coupling of GPCRs to members of the Gq/11 protein family results in activation of inositol trisphosphate (IP3) and accumulation of calcium intracellularly. This protocol chapter outlines a step-by-step guide for utilizing the inositol phosphate-1 (IP1) accumulation assay, a time-resolved fluorescence resonance energy transfer (TR-FRET) method, to investigate Gq-IP3 signaling. The assay serves as a valuable tool for those conducting pharmacological investigations and compound screening targeting this critical cellular pathway. This protocol chapter covers experimental setup, sample preparation, and data analysis, providing researchers with an in-depth guide to explore the pharmacology of Gq-coupled receptors.

Important Roles of PI3K/AKT Signaling Pathway and Relevant Inhibitors in Prostate Cancer Progression.

Prostate cancer (PCa) is an extremely common malignant tumor of the male genitourinary system, originating from the prostate gland epithelium. Male patients are prone to relapse after treatment, which seriously threatens their health. Phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB, also known as Akt) plays an important role in the growth, invasion, and metastasis of PCa. This review aimed to present an overview of the mechanism of action of the PI3K/AKT signaling pathway in PCa and discuss the application prospects of inhibitors of this pathway in treating PCa, providing a theoretical basis and reference for its clinical treatment targets.

Effects of feeding diets without mineral P supplement on intestinal phytate degradation, blood concentrations of Ca and P, and excretion of Ca and P in two laying hen strains before and after onset of laying activity.

The objective of this study was to characterize intestinal phytate degradation and mineral utilization by 2 laying hen strains before and after the onset of egg laying using diets without or with a mineral phosphorus (P) supplement. One offspring of 10 roosters per strain (Lohmann Brown-classic [LB] and Lohmann LSL-classic [LSL]) was sacrificed before (wk 19) and after (wk 24) the onset of egg-laying activity and following 4 wk placement in a metabolic unit. Diets were corn-soybean meal-based and without supplemented P (P-) or with 1 g/kg supplemented P (P+) from monocalcium phosphate. In wk 19 and 24, the blood plasma and digesta of duodenum+jejunum and distal ileum were collected. The concentration of P in blood plasma was higher in hens fed P+ than P- (P < 0.001). In duodenum + jejunum and ileum content, the concentrations of InsP6, Ins(1,2,4,5,6)P5 and Ins(1,2,3,4,5)P5 were lower in P- than in P+ (P ≤ 0.009). In duodenum+jejunum, the concentrations of InsP6, Ins(1,2,4,5,6)P5 and Ins(1,2,3,4,5)P5 were lower in wk 24 than 19 and lower in LSL than LB hens (P < 0.001). The concentration of myo-inositol (MI) in duodenum + jejunum content was lower in wk 19 than 24 (P < 0.001). Following a 4-d total excreta collection, the retained amount of P was higher in P+ than P- (P < 0.001). Phosphorus retention was lower in LB hens fed P- than in other treatments (P × strain: P = 0.039). In the jejunal tissue, some genes related to intracellular InsP metabolism were higher expressed in LB than LSL hens. The renunciation of mineral P increased endogenous phytate degradation, but more P was retained with supplemented P. Differences in endogenous phytate degradation between the periods before and after the onset of egg laying might be attributed to different Ca concentrations in intestinal digesta caused by different Ca needs in both periods.

The IP3R inhibitor desmethylxestospongin B reduces tumor cell migration, invasion and metastasis by impairing lysosome acidification and ß1-integrin recycling.

Cancer is the second leading cause of death worldwide. >90 % of cancer-related deaths are due to metastasis, a process that depends on the ability of cancer cells to leave the primary tumor, migrate, and colonize different tissues. Inositol 1,4,5-trisphosphate receptor (IP3R)-mediated Ca2+ signaling plays an essential role in maintaining the homeostasis of cancer cells and the sustained proliferation. Desmethylxestospongin B (dmXeB) is a specific inhibitor of the IP3R that selectively arrests cell proliferation and promotes cancer cell death at high concentrations. However, whether migration, invasion and metastasis can be affected by this drug is unknown. Here, by using the highly metastatic triple negative breast cancer (TNBC) cell line MDA-MB-231, we demonstrate that a prolonged inhibition of IP3R-mediated Ca2+ signals with dmXeB significantly reduces cell migration and invasion in vitro and metastasis in vivo. We found that this phenomenon was independent of the bioenergetic control of IP3R over the mitochondria and AMPK activation. Furthermore, employing a tandem LC3-GFP-mcherry assay, we found that prolonged inhibition of IP3R with dmXeB leads to diminished autophagic flux. This reduction can be attributed to impaired lysosomal acidification, as evidenced by assessments using DQ-BSA and pHrodo. Since cell migration requires appropriate assembly and disassembly of focal adhesions, along with the internalization and recycling of integrins via autophagy, we explored the dependency of integrin recycling from autophagosomes, finding that IP3R inhibition with dmXeB impaired the recycling of ß1-integrins, which accumulated within autophagosomes. Our findings reveal an unexpected effect of IP3R inhibition with dmXeB in cancer cells that could represent a novel therapeutic strategy for the treatment of cancer metastasis.

SlMIPS2, a myo-inositol phosphate synthase gene, regulates phosphate homeostasis by influencing SlPHL1 and SlSPX2 levels in tomato seedlings.

Phosphorus (P) is a quintessential macronutrient utilized by plants to support various metabolic processes during growth and development. Recent studies have revealed the pivotal role of inositol hexa-kis/pyrophosphate (InsP6-8), the derivatives of Myo-inositol (MI), in facilitating the interaction between SYG1/PHO81/XPR1 (SPX) and Phosphate starvation response (PHR) proteins. Myo-inositol phosphate synthase (MIPS) catalyzes the first committed step in MI biosynthesis. Although the role of MIPS genes in mediating stress responses in plants is well elucidated, its role in phosphate (Pi) deficiency remains largely unexplored. This study demonstrates that out of the five MIPS genes encoded by the tomato genome, only SlMIPS2 is sharply induced at an early stage of Pi starvation in tomato seedlings. Silencing of SlMIPS2 led to improved seedling growth with enhanced total soluble Pi and total P levels in the silenced plants under high Pi availability. SlMIPS2 silencing also caused a significant reduction in MI and InsP6 content in the tomato seedlings. These seedlings with depleted InsP6 levels accumulated lower levels of SlSPX2 protein. In contrast, stabilized SlPHL1 levels were noticed in these plants, directly implicating this transcription factor in activating phosphate starvation inducible (PSI) genes in the SlMIPS2-silenced seedlings, even under high Pi conditions. The results assign a novel role to SlMIPS2 in regulating cellular InsP6 levels and SPX-PHR interactions to control Pi homeostasis in tomato seedlings.

To quest new targets of Plasmodium parasite and their potential inhibitors to combat antimalarial drug resistance.

Malaria remains a global health challenge with significant mortality and morbidity annually, with resistant parasite strains complicating treatment efforts. There is an acute need for novel antimalarial drugs that can put a stop to the future public health crisis caused by the multi-drug resistance strains of the Plasmodium parasite. However, the discovery of these new components is very challenging in the context of the generation of multi-drug resistance properties of malaria. The novel drugs also need to have several properties involving enhanced therapeutic prospects, successful treatment capabilities, and novel mechanisms of action that will forestall the resistance. To successfully achieve this aim researchers are trying to focus on exploring promising malaria targets. Various approaches have been made for the development of drugs for malaria including the remodelling of existing drugs and the development of novel inhibitors which acts on new targets. Advancement in the study provides more information on the biology of parasites and the new targets which help in the development of novel drugs. The present review focuses on the study of novel targets of malaria parasites and subsequent inhibitors of those particular targets. Some of these targets include malarial protease, various transporter proteins, enzymes involved in the synthesis of DNA, and nucleic acids like dihydroorotate dehydrogenase, dihydrofolate reductase, apicoplast and dihydropteroate synthase. Other potential targets are also included in this review such as isoprenoid biosynthesis, farnesyl transferase of parasite, P. falciparum translational elongation factor 2, and phosphatidyl inositol 4 kinase. These promising targets have also been summed up along with their corresponding inhibitors for combating multi-drug resistance malaria.

The role of inositols during pregnancies complicated by gestational diabetes mellitus: a narrative review.

Pregnancy is a critical period marked by intricate physiological changes and maintaining maternal and fetal well-being is paramount. Inositols, a group of naturally occurring sugar alcohols, have gained attention for their potential benefits during pregnancy. This abstract provides a comprehensive review of the current literature on using inositols, primarily myo-inositol (MI) and D-chiro-inositol (DCI) in pregnancy. Inositols are crucial in cellular signal transduction and insulin sensitivity, making them integral to various physiological processes. Several studies suggest that inositols may contribute to preventing and managing gestational diabetes mellitus (GDM). MI, in particular, has shown promise in improving insulin sensitivity and mitigating insulin resistance, thereby influencing glucose metabolism. As our understanding of inositol's role in pregnancy deepens, it may emerge as a valuable supplement to enhance maternal and fetal health outcomes.

Ion chromatography coupled with optical emission spectrometry (IC-ICP-OES) methodology for the analysis of inositol phosphates in food and feed.

This study presents the development of ion chromatography coupled with inductively coupled plasma optical emission spectrometry (IC-ICP-OES) for the simultaneous determination and quantification of inositol phosphates (InsPx). Using a CarboPac PA100 column with a nitric acid-water gradient, 28 InsPx isomers (InsP6 to InsP2) were separated within 33 min. The method eliminates baseline drift and post-column derivatization thereby simplifying detection and quantification. It achieves low detection limits of 63 µg/L P across a range of 63-3200 µg/L P. Various extraction and sample preparation methods for food and feed matrices were tested, including acidic and alkaline agents, C18 SPE and spin concentrators. The analysis shows intra-day and intra-laboratory reproducibility with deviations smaller than 1 % for standard solutions and under 4 % for feed samples (80 % recovery rate of phytate). This methodology is applicable to explore enzymatic degradation pathways and the analysis of InsPx in complex food and animal feed matrices.

Diacerein and myo-inositol alleviate letrozole-induced PCOS via modulation of HMGB1, SIRT1, and NF-kB: A comparative study.

Polycystic ovary syndrome (PCOS) is the most prevalent cause of anovulatory infertility in women. Myo-inositol supplementation has displayed effectiveness in curing PCOS patients. Diacerein, an anti-inflammatory medication, has not been extensively studied in the context of reproductive disorders. This study aimed to compare the role of myo-inositol and diacerein in PCOS and the probable mechanisms mediating their actions. Forty adult female rats were divided equally into the following: control, PCOS, PCOS+Myo-inositol, and PCOS+Diacerein groups. Rats were subjected to arterial blood pressure (ABP), electromyography (EMG), and uterine reactivity measurements. Blood samples were collected for measuring hormonal assays, glycemic state, lipid profile, oxidative stress, and inflammatory markers. Ovaries and uteri were extracted for histological examination, including hematoxylin and eosin staining, Masson's trichrome staining, immunohistochemistry, and rt-PCR analysis of ovarian tissues. PCOS was associated with significant increases in ABP, uterine frequency and amplitude of contraction, luteinizing hormone, testosterone, lipid, glycemic and inflammatory markers, malondialdehyde, high-mobility group box 1 (HMGB1), nuclear factor kappa (NF-kB), ovarian fibrosis, and endometrial thickening. In contrast, there was a significant reduction in follicular stimulating hormone, reduced glutathione, and Sirtuin 1 (SIRT1) when compared with control group. Both myo-inositol and diacerein counteract PCOS changes; but diacerein's effects were superior to myo-inositol's for all parameters, except for lipid and glycemic markers. Diacerein possessed anti-inflammatory properties and showed significant efficacy in mitigating the endocrinal, metabolic, and ovarian structural alterations linked to PCOS. Its beneficial actions likely stem from reducing oxidative stress, dyslipidemia, and hyperglycemia, potentially through the modulation of HMGB1, SIRT1, and NF-kB pathways.

Myo-Inositol and D-Chiro-Inositol Reduce DHT-Stimulated Changes in the Steroidogenic Activity of Adult Granulosa Cell Tumors.

Considering the properties of myo-inositol (MI) and D-chiro-inositol (DCI), which are well known in polycystic ovary syndrome therapy, and the limitations of adult granulosa cell tumor (AGCT) treatment, especially for androgen-secreting tumors, we studied the role of MI and DCI in the androgen-rich environment of AGCTs. For this purpose, we analyzed the mRNA expression of steroidogenic genes and the secretion of progesterone (P4) and 17ß-estradiol (E2) in an unstimulated and/or dihydrotestosterone (DHT)-stimulated environment under MI and DCI influence. Thus, we used the HGrC1 and KGN cell lines as in vitro models of healthy and cancerous granulosa cells. We found that DHT, the most potent androgen, increased E2 secretion and steroidogenic acute regulatory protein (StAR) and cytochrome P450 side-chain cleavage gene (CYP11A1) mRNA expression without affecting 450 aromatase (CYP19A1) in AGCTs. However, after the MI and DCI treatment of KGN cells, both compounds strongly reduced StAR and CYP11A1 expression. Interestingly, in DHT-stimulated KGN cells, only DCI alone and its cotreatment with MI reduced both CYP11A1 mRNA and E2 secretion. These findings suggest that CYP11A1 is responsible for the antiestrogenic effect of DCI in the androgen-rich environment of AGCTs. Therefore, MI and DCI could be used as effective agents in the adjuvant treatment of AGCT, but further detailed studies are needed.

Diversification of sphingolipid synthase activities in kinetoplastid protozoa.

Phosphosphingolipids (PSL) are essential components of eukaryotic membranes. The major PSL in fungi and protists is inositol phosphorylceramide (IPC), while sphingomyelin (SM), and to a lesser extent ethanolamine phosphorylceramide (EPC) predominate in mammals. Most kinetoplastid protozoa have a syntenic locus that encodes a single sphingolipid synthase (SLS) gene. Uniquely, among the kinetoplastids, the salivarian (African) trypanosomes have expanded this locus from a single gene in Trypanosoma vivax (TvSLS) to four genes in T. brucei (TbSLS1-4). We have previously shown that one of these is an IPC synthase, while the others are SM/EPC synthases, and that specificity is controlled by a single signature residue (IPC, serine; SM/EPC, phenylalanine). This residue is serine in T. cruzi and Leishmania major SLSs, both of which are demonstrated IPC synthases. However, T. vivax has a tyrosine at this residue raising the issue of specificity. Using a liposome-supplemented in vitro translation system we now show that T. vivax SLS is an SM/EPC synthase, and that the basal kinetoplastid Bodo saltans SLS is an IPC synthase (serine). We use these data, and a multiple alignment of available sequences, to discuss the evolution of kinetoplastid SLSs and their unique expansion in T. brucei and related salivarian trypanosomes.

Discovery and evaluation of novel SHIP-1 inhibitors.

Src Homology 2-containing Inositol 5'-Phosphatase-1 (SHIP-1), encoded by INPP5D, has been identified as an Alzheimer's disease (AD) risk-associated gene through recent genetic and epigenetic studies. SHIP-1 confers AD risk by inhibiting the TREM2 cascade and reducing beneficial microglial cellular processes, including phagocytosis. While several small molecules have been reported to modulate SHIP-1 activity, their limited selectivity and efficacy in advanced models restricted their potential as therapeutic agents or probes for biological studies. Herein, we validated and implemented a high-throughput screening platform to explore new chemotypes that can modulate the phosphatase activity of SHIP-1. We screened 49,260 central nervous system (CNS)-penetrate compounds sourced from commercial vendors using the malachite green-based assay for anti-SHIP-1 activity. Through analysis, prioritization, and validation of the screening hits, we identified three novel types of scaffolds that inhibit the SHIP-1 phosphatase activity with IC50s as low as 46.6 µM. To improve the inhibitory activity of these promising hits, we carried out structure-activity relationship (SAR) studies, resulting in a lead molecule SP3-12 that inhibits SHIP-1 with an IC50 value of 6.1 µM. Kinetic analyses of SP3-12 revealed that its inhibition mechanism is competitive, with a Ki value of 3.2 µM for SHIP-1 and a 7-fold selectivity over SHIP-2. Furthermore, results from testing in a microglial phagocytosis/cell health high content assay indicated that SP3-12 could effectively activate phagocytosis in human microglial clone 3 (HMC3) cells, with an EC50 of 2.0 µM, without cytotoxicity in the dose range. Given its potency, selectivity, and cellular activity, SP3-12 emerges as a promising small molecule inhibitor with potential for investigating the biological functions of SHIP-1.

Antioxidant and anticoagulant properties of myo-inositol determined in an ex vivo studies and gas chromatography analysis.

Myo-inositol plays a key role in the vasculature and may be beneficial for preventing harmful environmental effects. In this study aortic rings were isolated from middle-aged (12-month-old) male Wistar rats and preincubated with myo-inositol (0.01-100 mg/L) for 2 h. A stable thromboxane A2 analog was added (0.1 nM, 2 h) to analyze vascular dysfunction. The concentration of myo-inositol in the organ baths was determined via gas chromatography. In another experiment, human blood plasma was subjected to pro-oxidant - hydrogen peroxide administration, and myo-inositol was added to analyze lipid and protein oxidation processes. The thromboplastin time, prothrombin time, and thrombin time were also studied. Myo-inositol administration protected thiol groups against oxidative stress, meanwhile decreased vascular contraction and potentiated vasodilation (concentrations 1-100 mg/L, but not ≤ 0.1 mg/L), and changed the level of 8-isoprostane (concentrations: 0.1-100 mg/L, but not 0.01 mg/L) in plasma treated with H2O2/Fe2+. A dose above 100 mg/L additionally protected lipids (measured as thiobarbituric acid reactive substances) and increased thrombin time. Moreover, significant differences in vascular relaxation were observed between the studied myo-inositol concentrations (1 vs. 10 vs. 100 mg/L), which was not detected under the 0.1 mg/L. The concentration of myo-inositol in the organ baths determined via gas chromatography revealed that this nutraceutical agent was not used by the aortic rings during the incubation period in physiological processes. A protective effect of myo-inositol against prooxidant damage to human plasma and rat thoracic arteries has been demonstrated.

Increased TRPV4 Channel Expression Enhances and Impairs Blood Vessel Function in Hypertension.

BACKGROUND: Endothelial cell TRPV4 (transient receptor potential vanilloid 4) channels provide a control point that is pivotal in regulating blood vessel diameter by mediating the Ca2+-dependent release of endothelial-derived vasoactive factors. In hypertension, TRPV4-mediated control of vascular function is disrupted, but the underlying mechanisms and precise physiological consequences remain controversial. METHODS: Here, using a comprehensive array of methodologies, endothelial TRPV4 channel function was examined in intact mesenteric resistance arteries from normotensive Wistar-Kyoto and spontaneously hypertensive rats. RESULTS: Our results show there is a notable shift in vascular reactivity in hypertension characterized by enhanced endothelium-dependent vasodilation at low levels of TRPV4 channel activation. However, at higher levels of TRPV4 activity, this vasodilatory response is reversed, contributing to the aberrant vascular tone observed in hypertension. The change in response, from dilation to constriction, was accompanied by a shift in intracellular Ca2+ signaling modalities arising from TRPV4 activity. Oscillatory TRPV4-evoked IP3 (inositol triphosphate)-mediated Ca2+ release, which underlies dilation, decreased, while the contraction inducing sustained Ca2+ rise, arising from TRPV4-mediated Ca2+ influx, increased. Our findings also reveal that while the sensitivity of endothelial cell TRPV4 to activation was unchanged, expression of the channel is upregulated and IP3 receptors are downregulated in hypertension. CONCLUSIONS: These data highlight the intricate interplay between endothelial TRPV4 channel expression, intracellular Ca2+ signaling dynamics, and vascular reactivity. Moreover, the data support a new unifying hypothesis for the vascular impairment that accompanies hypertension. Specifically, endothelial cell TRPV4 channels play a dual role in modulating blood vessel function in hypertension.

The effect of myo-inositol antioxidant activity on human sperm parameters and DNA damage in ultra-rapid and conventional freezing methods.

Male fertility preservation is still challenged by cell damage induced during sperm cryopreservation and impaired sperm structure and function. Sperm ultra-rapid freezing, despite a higher protective effect compared to conventional freezing method, is still associated with suboptimal sperm cryosurvival and needs to be modified to increase its efficiency in sperm protection. Sperm freezing media supplemented with antioxidants can improve sperm parameters following freezing-warming process. In this study, we aimed to investigate the effect of employing ultra-rapid freezing and myo-inositol on sperm cryosurvival. Thirty semen samples with normal sperm parameters were collected and each one was divided into four portions to cryopreserve by conventional freezing, ultra-rapid freezing, conventional freezing + myo-inositol 2 mg/ml, and ultra-rapid freezing + myo-inositol 2 mg/ml. Sperm samples warmed after at least 24 h of freezing and sperm cryosurvival were analyzed by evaluation of sperm motility, viability, morphology and DNA fragmentation index (DFI). Freezing method had a significant influence on post-thaw sperm DFI and morphology (p < 0.05) and the interaction between freezing method and antioxidant supplementation significantly affected sperm morphology (p < 0.05). The highest percentage of sperm normal morphology and minimal DFI was achieved using ultra-rapid freezing supplemented by myo-inositol antioxidant compared to other groups (P < 0.05). The highest sperm DNA damage after freezing-warming was observed following the conventional freezing method. In conclusion, sperm freezing method was identified as factor strongly influencing sperm DFI and morphology after thawing/warming. Sperm samples can be rapidly frozen using the modified freezing media supplemented by myo-inositol without impacting sperm DNA and morphology.

Hexokinase 2 senses fructose in tumor-associated macrophages to promote colorectal cancer growth.

Fructose is associated with colorectal cancer tumorigenesis and metastasis through ketohexokinase-mediated metabolism in the colorectal epithelium, yet its role in the tumor immune microenvironment remains largely unknown. Here, we show that a modest amount of fructose, without affecting obesity and associated complications, promotes colorectal cancer tumorigenesis and growth by suppressing the polarization of M1-like macrophages. Fructose inhibits M1-like macrophage polarization independently of fructose-mediated metabolism. Instead, it serves as a signal molecule to promote the interaction between hexokinase 2 and inositol 1,4,5-trisphophate receptor type 3, the predominant Ca2+ channel on the endoplasmic reticulum. The interaction reduces Ca2+ levels in cytosol and mitochondria, thereby suppressing the activation of mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 1 (STAT1) as well as NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome activation. Consequently, this impedes M1-like macrophage polarization. Our study highlights the critical role of fructose as a signaling molecule that impairs the polarization of M1-like macrophages for tumor growth.

Using Native and Synthetic Genes to Disrupt Inositol Pyrophosphates and Phosphate Accumulation in Plants.

Inositol pyrophosphates are eukaryotic signaling molecules that have been recently identified as key regulators of plant phosphate sensing and homeostasis. Given the importance of phosphate to current and future agronomic practices, we sought to design plants which could be used to sequester phosphate, as a step in a phytoremediation strategy. To achieve this, we expressed Diadenosine and Diphosphoinositol Polyphosphate Phosphohydrolase (DDP1), a yeast (Saccharomyces cerevisiae) enzyme demonstrated to hydrolyze inositol pyrophosphates, in Arabidopsis thaliana and pennycress (Thlaspi arvense), a spring annual cover crop with emerging importance as a biofuel crop. DDP1 expression in Arabidopsis decreased inositol pyrophosphates, activated Phosphate Starvation Response marker genes, and increased phosphate accumulation. These changes corresponded with alterations in plant growth and sensitivity to exogenously applied phosphate. Pennycress plants expressing DDP1 displayed increases in phosphate accumulation, suggesting that these plants could potentially serve to reclaim phosphate from phosphate-polluted soils. We also identified a native Arabidopsis gene, Nucleoside diphosphate-linked moiety X 13 (NUDIX13), which we show encodes an enzyme homologous to DDP1 with similar substrate specificity. Arabidopsis transgenics overexpressing NUDIX13 had lower inositol pyrophosphate levels and displayed phenotypes similar to DDP1-overexpressing transgenics, while nudix13-1 mutants had increased levels of inositol pyrophosphates. Taken together, our data demonstrates that DDP1 and NUDIX13 can be used in strategies to regulate plant inositol pyrophosphates and could serve as potential targets for engineering plants to reclaim phosphate from polluted environments.

The effect of myo-inositol supplementation on AMPK/PI3K/AKT pathway and insulin resistance in patients with NAFLD.

Insulin resistance (IR) is the pivotal pathological hit in non-alcoholic fatty liver disease (NAFLD). There is specific attention to combination/conjugated therapies for NAFLD management. As myo-inositol (MI) has been shown to improve IR in animal and human trials, this study aimed to investigate the influence of MI supplementation on glycemic response and IR through AMPK/PI3K/AKT signaling pathway in obese patients with NAFLD. This double-blinded placebo-controlled randomized clinical trial was conducted on 48 obese (BMI = 30-40 kg/m2) patients with NAFLD who were randomly assigned to receiving either MI (4 g/day) or placebo (maltodextrin 4 g/day) group for 8 weeks. Before and after the trial, weight, height, serum glycemic parameters (inc. fasting glucose and insulin) as well as IR indices were assessed. Moreover, the mRNA expression levels of AMPK, AKT, and PDK-1 in peripheral blood mononuclear cells (PBMCs) were determined. MI supplementation resulted in significant increases in the fold changes of AMPK, AKT, and PDK-1 genes (p = .019, p = .049, and p = .029, respectively). Indeed, IR improved in terms of all IR indices in MI group (p < .05) after adjusting for the confounders, apart from quantitative insulin sensitivity check index (QUICKI). The results showed that MI supplementation not only upregulated AMPK, AKT, and PDK-1 mRNA in PBMCs but also improved IR in obese patients with NAFLD.

A non-catalytic role of IPMK is required for PLCγ1 activation in T cell receptor signaling by stabilizing the PLCγ1-Sam68 complex.

BACKGROUND: Phospholipase C gamma 1 (PLCγ1) is an important mediator of the T cell receptor (TCR) and growth factor signaling. PLCγ1 is activated by Src family kinases (SFKs) and produces inositol 1,4,5-triphosphate (InsP3) from phosphatidylinositol 4,5-bisphosphate (PIP2). Inositol polyphosphate multikinase (IPMK) is a pleiotropic enzyme with broad substrate specificity and non-catalytic activities that mediate various functional protein-protein interactions. Therefore, IPMK plays critical functions in key biological events such as cell growth. However, the contribution of IPMK to the activation of PLCγ1 in TCR signaling remains mostly unelucidated. The current study aimed to elucidate the functions of IPMK in TCR signaling and to uncover the mode of IPMK-mediated signaling action in PLCγ1 activation. METHODS: Concanavalin A (ConA)-induced acute hepatitis model was established in CD4+ T cell-specific IPMK knockout mice (IPMKΔCD4). Histological analysis was performed to assess hepatic injury. Primary cultures of naïve CD4+ T cells were used to uncover the role of mechanisms of IPMK in vitro. Western blot analysis, quantitative real-time PCR, and flow cytometry were performed to analyze the TCR-stimulation-induced PLCγ1 activation and the downstream signaling pathway in naïve CD4+ T cells. Yeast two-hybrid screening and co-immunoprecipitation were conducted to identify the IPMK-binding proteins and protein complexes. RESULTS: IPMKΔCD4 mice showed alleviated ConA-induced acute hepatitis. CD4+ helper T cells in these mice showed reduced PLCγ1 Y783 phosphorylation, which subsequently dampens calcium signaling and IL-2 production. IPMK was found to contribute to PLCγ1 activation via the direct binding of IPMK to Src-associated substrate during mitosis of 68 kDa (Sam68). Mechanistically, IPMK stabilizes the interaction between Sam68 and to PLCγ1, thereby promoting PLCγ1 phosphorylation. Interfering this IPMK-Sam68 binding interaction with IPMK dominant-negative peptides impaired PLCγ1 phosphorylation. CONCLUSIONS: Our results demonstrate that IPMK non-catalytically promotes PLCγ1 phosphorylation by stabilizing the PLCγ1-Sam68 complex. Targeting IPMK in CD4+ T cells may be a promising strategy for managing immune diseases caused by excessive stimulation of TCR.