The "Other" Inositols and Their Phosphates: Synthesis, Biology, and Medicine (with Recent Advances in myo-Inositol Chemistry)

Update on the combination of myo-inositol/d-chiro-inositol for the treatment of polycystic ovary syndrome

In this article, we present a narrative review on the use of inositol in the treatment of polycystic ovary syndrome (PCOS). Of the different inositols that exist, only myo-inositol (MYO) and D-chiro inositol (DCI) have been studied in the treatment of PCOS. The results of the studies show that there is insufficient or controversial evidence to recommend the use of DCI alone, while MYO alone shows positive results and, above all, the MYO/DCI combination is effective when used at a ratio of at least 40:1, but there is enough rationale to further study ratios such as 66:1 to 100:1 as other possible effective combinations.

Efficient pathway-driven scyllo-inositol production from myo-inositol using thermophilic cells and mesophilic inositol dehydrogenases: a novel strategy for pathway control

Mesophilic enzymes, which are active at moderate temperatures, may dominate enzymatic reactions even in the presence of thermophilic crude enzymes. This study was conducted to investigate this hypothesis with mesophilic inositol dehydrogenases (IolG and IolX) produced in Geobacillus kaustophilus HTA426. To ensure the efficient production of mesophilic enzymes, we first screened for promoters induced at moderate temperatures using transcriptome analysis and identified four genes highly expressed at 30°C in the thermophile. We further characterized these promoters using fluorescent reporter assays to determine that the mti3 promoter could direct efficient gene expression at 40°C. We cloned the promoter into an Escherichia coli-Geobacillus shuttle plasmid and confirmed that the resulting vector functioned in G. kaustophilus and other thermophiles. We then used this vector for the cooperative expression of the iolG and iolX genes from Bacillus subtilis 168. G. kaustophilus cells carrying the expression vector were incubated at 60°C for cellular propagation and then at 40°C for the production of IolG and IolX. When the cells were permeabilized, IolG and IolX acted as catalysts to convert exogenous myo-inositol into scyllo-inositol at 30°C. In a scaled-up reaction, 10 g of myo-inositol was converted to 1.8 g of scyllo-inositol, which was further purified to yield 970 mg of pure powder. Notably, myo-inositol was degraded by intrinsic enzymes of G. kaustophilus at 60°C but not at 30°C, supporting our initial hypothesis. We indicate that this approach is useful for preparing enzyme cocktails without the need for purification.

IMPORTANCE

Enzyme cocktails are commonly employed for cell-free chemical synthesis; however, their preparation involves cumbersome processes. This study affirms that mesophilic enzymes in thermophilic crude extracts can function as specific catalysts at moderate temperatures, akin to enzyme cocktails. The catalyst was prepared by permeabilizing cells without the need for concentration, extraction, or purification processes; hence, its preparation was considerably simpler compared with conventional methods for enzyme cocktails. This approach was employed to produce pure scyllo-inositol from an economical substrate. Notably, this marks the first large-scale preparation of pure scyllo-inositol, holding potential pharmaceutical significance as scyllo-inositol serves as a promising agent for certain diseases but is currently expensive. Moreover, this approach holds promise for application in pathway engineering within living cells. The envisioned pathway is designed without chromosomal modification and is simply regulated by switching culture temperatures. Consequently, this study introduces a novel platform for both whole-cell and cell-free synthetic systems.

Microbial synthesis of health-promoting inositols

D-chiro-inositol and scyllo-inositol are known for their health-promoting properties and promising as ingredients for functional foods. Strains of Bacillus subtilis and Corynebacterium glutamicum were created by metabolic engineering capable of inexpensive production of these two rare inositols from myo-inositol, which is the most common inositol in nature. In addition, further modifications have enabled the synthesis of the two rare inositols from the much-cheaper carbon sources, glucose or sucrose.

Synthesis of the Reducing-end Hexasaccharide Fragment of Marine Lipopolysaccharide Axinelloside A

Chemical synthesis of an orthogonally protected hexasaccharide relevant to the reducing-end half of axinelloside A, a highly sulfated marine lipopolysaccharide, is disclosed. The synthesis features preparation of the scyllo-inositol unit via a Ferrier-type-II rearrangement, construction of the 1,2-cis-glycosidic bonds via remote participation, and concise [2+2+2] assembly via Au(I)-catalyzed glycosylation.

Substrate promiscuity of inositol 1,4,5-trisphosphate kinase driven by structurally-modified ligands and active site plasticity

D-myo-inositol 1,4,5-trisphosphate (InsP3) is a fundamental second messenger in cellular Ca2+ mobilization. InsP3 3-kinase, a highly specific enzyme binding InsP3 in just one mode, phosphorylates InsP3 specifically at its secondary 3-hydroxyl group to generate a tetrakisphosphate. Using a chemical biology approach with both synthetised and established ligands, combining synthesis, crystallography, computational docking, HPLC and fluorescence polarization binding assays using fluorescently-tagged InsP3, we have surveyed the limits of InsP3 3-kinase ligand specificity and uncovered surprisingly unforeseen biosynthetic capacity. Structurally-modified ligands exploit active site plasticity generating a helix-tilt. These facilitated uncovering of unexpected substrates phosphorylated at a surrogate extended primary hydroxyl at the inositol pseudo 3-position, applicable even to carbohydrate-based substrates. Crystallization experiments designed to allow reactions to proceed in situ facilitated unequivocal characterization of the atypical tetrakisphosphate products. In summary, we define features of InsP3 3-kinase plasticity and substrate tolerance that may be more widely exploitable.

Metabolomic biomarkers in liquid biopsy: accurate cancer diagnosis and prognosis monitoring

Liquid biopsy, a novel detection method, has recently become an active research area in clinical cancer owing to its unique advantages. Studies on circulating free DNA, circulating tumor cells, and exosomes obtained by liquid biopsy have shown great advances and they have entered clinical practice as new cancer biomarkers. The metabolism of the body is dynamic as cancer originates and progresses. Metabolic abnormalities caused by cancer can be detected in the blood, sputum, urine, and other biological fluids via systemic or local circulation. A considerable number of recent studies have focused on the roles of metabolic molecules in cancer. The purpose of this review is to provide an overview of metabolic markers from various biological fluids in the latest clinical studies, which may contribute to cancer screening and diagnosis, differentiation of cancer typing, grading and staging, and prediction of therapeutic response and prognosis.

Deciphering the potential of Sargassum tenerrimum extract: metabolic profiling and pathway analysis of groundnut (Arachis hypogaea) in response to Sargassum extract and Sclerotium rolfsii

Seaweed extracts have enormous potential as bio-stimulants and demonstrated increased growth and yield in different crops. The presence of physiologically active component stimulate plant stress signaling pathways, enhances growth and productivity, as well as serve as plant defense agents. The seaweed extracts can reduce the use of chemicals that harm the environment for disease management. In the present study, the Sargassum tenerrimum extract treatment was applied, alone and in combination with Sclerotium rolfsii, to Arachis hypogea, to study the differential metabolite expression. The majority of metabolites showed maximum accumulation with Sargassum extract-treated plants compared to fungus-treated plants. The different classes of metabolite compounds like sugars, carboxylic acids, polyols, showed integrated peaks in different treatments of plants. The sugars were higher in Sargassum extract and Sargassum extract + fungus treatments compared to control and fungus treatment, respectively. Interestingly, Sargassum extract + fungus treatment showed maximum accumulation of carboxylic acids. Pathway enrichment analysis showed regulation of different metabolites, highest impact with galactose metabolism pathway, identifying sucrose, myo-inositol, glycerol and fructose. The differential metabolite profiling and pathway analysis of groundnut in response to Sargassum extract and S. rolfsii help in understanding the groundnut- S. rolfsii interactions and the potential role of the Sargassum extract towards these interactions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-024-01418-9.

Stereoselective Voltammetric Biosensor for Myo-Inositol and D-Chiro-Inositol Recognition

This paper describes the development of a simple voltammetric biosensor for the stereoselective discrimination of myo-inositol (myo-Ins) and D-chiro-inositol (D-chiro-Ins) by means of bovine serum albumin (BSA) adsorption onto a multi-walled carbon nanotube (MWCNT) graphite screen-printed electrode (MWCNT-GSPE), previously functionalized by the electropolymerization of methylene blue (MB). After a morphological characterization, the enantioselective biosensor platform was electrochemically characterized after each modification step by differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The results show that the binding affinity between myo-Ins and BSA was higher than that between D-chiro-Ins and BSA, confirming the different interactions exhibited by the novel BSA/MB/MWCNT/GSPE platform towards the two diastereoisomers. The biosensor showed a linear response towards both stereoisomers in the range of 2-100 μM, with LODs of 0.5 and 1 μM for myo-Ins and D-chiro-Ins, respectively. Moreover, a stereoselectivity coefficient α of 1.6 was found, with association constants of 0.90 and 0.79, for the two stereoisomers, respectively. Lastly, the proposed biosensor allowed for the determination of the stereoisomeric composition of myo-/D-chiro-Ins mixtures in commercial pharmaceutical preparations, and thus, it is expected to be successfully applied in the chiral analysis of pharmaceuticals and illicit drugs of forensic interest.

Alpha Lipoic Acid Efficacy in PCOS Treatment: What Is the Truth?

Polycystic ovary syndrome (PCOS) is among the most common female endocrinopathies, affecting about 4-25% of women of reproductive age. Women affected by PCOS have an increased risk of developing metabolic syndrome, type 2 diabetes mellitus, cardiovascular diseases, and endometrial cancer. Given the pivotal role of insulin resistance (IR) in the pathogenesis of PCOS, in the last years, many insulin-sensitizing factors have been proposed for PCOS treatment. The first insulin sensitizer recommended by evidence-based guidelines for the assessment and treatment of PCOS was metformin, but the burden of side effects is responsible for treatment discontinuation in many patients. Inositols have insulin-mimetic properties and contribute to decreasing postprandial blood glucose, acting by different pathways. ALA is a natural amphipathic compound with a very strong anti-inflammatory and antioxidant effect and a very noteworthy role in the improvement of insulin metabolic pathway. Given the multiple effects of ALA, a therapeutic strategy based on the synergy between inositols and ALA has been recently proposed by many groups with the aim of improving insulin resistance, reducing androgen levels, and ameliorating reproductive outcomes in PCOS patients. The purpose of this study is to review the existing literature and to evaluate the existing data showing the efficacy and the limitation of a treatment strategy based on this promising molecule. ALA is a valid therapeutic strategy applicable in the treatment of PCOS patients: Its multiple actions, including antinflammatory, antioxidant, and insulin-sensitizing, may be of utmost importance in the treatment of a very complex syndrome. Specifically, the combination of MYO plus ALA creates a synergistic effect that improves insulin resistance in PCOS patients, especially in obese/overweight patients with T2DM familiarity. Moreover, ALA treatment also exerts beneficial effects on endocrine patterns, especially if combined with MYO, improving menstrual regularity and ovulation rhythm. The purpose of our study is to review the existing literature and to evaluate the data showing the efficacy and the limitations of a treatment strategy based on this promising molecule.

Alternative routes for production of the drug candidate d-chiro-inositol with Corynebacterium glutamicum using endogenous or promiscuous plant enzymes

d-chiro-Inositol (DCI) is a promising drug candidate for treating insulin resistance and associated diseases such as type 2 diabetes or polycystic ovary syndrome. In this study, we developed two production processes for DCI using Corynebacterium glutamicum as host. In the first process, myo-inositol (MI) is oxidized to 2-keto-myo-inositol (2KMI) by the inositol dehydrogenase (IDH) IolG and then isomerized to 1-keto-d-chiro-inositol (1KDCI) by the isomerases Cg0212 or Cg2312, both of which were identified in this work. 1KDCI is then reduced to DCI by IolG. Overproduction of IolG and Cg0212 in a chassis strain unable to degrade inositols allowed the production of 1.1 g/L DCI from 10 g/L MI. As both reactions involved are reversible, only a partial conversion of MI to DCI can be achieved. To enable higher conversion ratios, a novel route towards DCI was established by utilizing the promiscuous activity of two plant-derived enzymes, the NAD+-dependent d-ononitol dehydrogenase MtOEPa and the NADPH-dependent d-pinitol dehydrogenase MtOEPb from Medicago truncatula (barrelclover). Heterologous production of these enzymes in the chassis strain led to the production of 1.6 g/L DCI from 10 g/L MI. For replacing the substrate MI by glucose, the two plant genes were co-expressed with the endogenous myo-inositol-1-phosphate synthase gene ino1 either as a synthetic operon or using a novel, bicistronic T7-based expression vector. With the single operon construct, 0.75 g/L DCI was formed from 20 g/L glucose, whereas with the bicistronic construct 1.2 g/L DCI was obtained, disclosing C. glutamicum as an attractive host for of d-chiro-inositol production.

GC-MS based untargeted metabolomics reveals the metabolic response of earthworm (Eudrilus eugeniae) after chronic combinatorial exposure to three different pesticides

In this study GC-MS-based untargeted metabolomics was used to identify the metabolic response of earthworm; Eudrilus eugeniae exposed to sub-lethal concentrations of chlorpyrifos-CHL, cypermethrin-CYP, Glyphosate-GLY, and Combined-C (all three pesticides) at the concentrations of 3, 6, and 12 mg/kg. Principal component analysis of the obtained datasets revealed a clear distinction between the control and treatment groups. The mean weight of the worms in the treated groups decreased significantly (p < 0.05). Among the identified metabolites, oleic acid (~ 93.47%), lysine (~ 92.20%), glutamic acid (~ 91.81%), leucine (~ 90.20%), asparagine (~ 94.20%), methionine (~ 92.27%), malic acid (~ 93.37%), turanose (~ 95.04%), maltose (~ 92.36%), cholesta-3,5-diene (~ 86.11%), galactose (~ 93.20%), cholesterol (~ 91.56%), tocopherol (~ 85.09%), decreased significantly (p < 0.05), whereas myoinositol (~ 83%) and isoleucine (78.09%) increased significantly (p < 0.05) upon exposure to the CHL, CYP, GLY, and C. Overall, the findings suggest that earthworms might be a new entry point for the pesticides into the food chain. The present study highlights that metabolomics can be a reliable approach to understand the effect of different xenobiotics including pesticides on the metabolic response of earthworms.

Cyclitols: From Basic Understanding to Their Association with Neurodegeneration

One of the most common cyclitols found in eukaryotic cells-Myo-inositol (MI) and its derivatives play a key role in many cellular processes such as ion channel physiology, signal transduction, phosphate storage, cell wall formation, membrane biogenesis and osmoregulation. The aim of this paper is to characterize the possibility of neurodegenerative disorders treatment using MI and the research of other therapeutic methods linked to MI's derivatives. Based on the reviewed literature the researchers focus on the most common neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease and Spinocerebellar ataxias, but there are also works describing other seldom encountered diseases. The use of MI, d-pinitol and other methods altering MI's metabolism, although research on this topic has been conducted for years, still needs much closer examination. The dietary supplementation of MI shows a promising effect on the treatment of neurodegenerative disorders and can be of great help in alleviating the accompanying depressive symptoms.

Antiepileptic Properties of Scyllo-Inositol on Pentylenetetrazol-Induced Seizures

Epilepsy, with about 70 million affected people worldwide, is one of the biggest challenges of medicine today. It is estimated that about one-third of epileptic patients receive inadequate treatment. Inositols have proved effective in many disorders; hence, in the current study, we tested potential antiepileptic properties of scyllo-inositol (SCI)-one of the most common commercially available inositols-in zebrafish larvae with pentylenetetrazol-induced seizures. First, we studied the general effect of SCI on zebrafish motility, and then we tested SCI antiepileptic properties over short (1 h) and long (120 h) exposure protocols. Our results demonstrated that SCI alone does not reduce zebrafish motility regardless of the dose. We also observed that short-term exposure to SCI groups reduced PTZ-treated larva motility compared to controls (p < 0.05). In contrast, prolonged exposure did not produce similar results, likely due to the insufficient concentration of SCI given. Our results highlight the potential of SCI use in epilepsy treatment and warrant further clinical studies with inositols as potential seizure-reducing drugs.

Myo-Inositol and D-Chiro-Inositol as Modulators of Ovary Steroidogenesis: A Narrative Review

Myo-inositol is a natural polyol, the most abundant among the nine possible structural isomers available in living organisms. Inositol confers some distinctive traits that allow for a striking distinction between prokaryotes and eukaryotes, the basic clusters into which organisms are partitioned. Inositol cooperates in numerous biological functions where the polyol participates or by furnishing the fundamental backbone of several related derived metabolites, mostly obtained through the sequential addition of phosphate groups (inositol phosphates, phosphoinositides, and pyrophosphates). Overall myo-inositol and its phosphate metabolites display an entangled network, which is involved in the core of the biochemical processes governing critical transitions inside cells. Noticeably, experimental data have shown that myo-inositol and its most relevant epimer D-chiro-inositol are both necessary to permit a faithful transduction of insulin and of other molecular factors. This improves the complete breakdown of glucose through the citric acid cycle, especially in glucose-greedy tissues, such as the ovary. In particular, while D-chiro-inositol promotes androgen synthesis in the theca layer and down-regulates aromatase and estrogen expression in granulosa cells, myo-inositol strengthens aromatase and FSH receptor expression. Inositol effects on glucose metabolism and steroid hormone synthesis represent an intriguing area of investigation, as recent results have demonstrated that inositol-related metabolites dramatically modulate the expression of several genes. Conversely, treatments including myo-inositol and its isomers have proven to be effective in the management and symptomatic relief of a number of diseases associated with the endocrine function of the ovary, namely polycystic ovarian syndrome.

The Role of Inositols in the Hyperandrogenic Phenotypes of PCOS: A Re-Reading of Larner’s Results

Polycystic ovarian syndrome (PCOS) is the most common endocrinological disorder in women, in which, besides chronic anovulation/oligomenorrhea and ovarian cysts, hyperandrogenism plays a critical role in a large fraction of subjects. Inositol isomers—myo-Inositol and D-Chiro-Inositol—have recently been pharmacologically effective in managing many PCOS symptoms while rescuing ovarian fertility. However, some disappointing clinical results prompted the reconsideration of their specific biological functions. Surprisingly, D-Chiro-Ins stimulates androgen synthesis and decreases the ovarian estrogen pathway; on the contrary, myo-Ins activates FSH response and aromatase activity, finally mitigating ovarian hyperandrogenism. However, when the two isomers are given in association—according to the physiological ratio of 40:1—patients could benefit from myo-Ins enhanced FSH and estrogen responsiveness, while taking advantage of the insulin-sensitizing effects displayed mostly by D-Chiro-Ins. We need not postulate insulin resistance to explain PCOS pathogenesis, given that insulin hypersensitivity is likely a shared feature of PCOS ovaries. Indeed, even in the presence of physiological insulin stimulation, the PCOS ovary synthesizes D-Chiro-Ins four times more than that measured in control theca cells. The increased D-Chiro-Ins within the ovary is detrimental in preserving steroidogenic control, and this failure can easily explain why treatment strategies based upon high D-Chiro-Ins have been recognized as poorly effective. Within this perspective, two factors emerge as major determinants in PCOS: hyperandrogenism and reduced aromatase expression. Therefore, PCOS could no longer be considered a disease only due to increased androgen synthesis without considering the contemporary downregulation of aromatase and FSH receptors. Furthermore, these findings suggest that inositols can be specifically effective only for those PCOS phenotypes featured by hyperandrogenism.

Cu-catalysed enantioselective radical heteroatomic S-O cross-coupling

The transition-metal-catalysed cross-coupling reaction has established itself as one of the most reliable and practical synthetic tools for the efficient construction of carbon-carbon/heteroatom (p-block elements other than carbon) bonds in both racemic and enantioselective manners. In contrast, development of the corresponding heteroatom-heteroatom cross-couplings has so far remained elusive, probably due to the under-investigated and often challenging heteroatom-heteroatom reductive elimination. Here we demonstrate the use of single-electron reductive elimination as a strategy for developing enantioselective S-O coupling under Cu catalysis, based on both experimental and theoretical results. The reaction manifests its synthetic potential by the ready preparation of challenging chiral alcohols featuring congested stereocentres, the expedient valorization of the biomass-derived feedstock glycerol, and the remarkable catalytic 4,6-desymmetrization of inositol. These results demonstrate the potential of enantioselective radical heteroatomic cross-coupling as a general chiral heteroatom-heteroatom formation strategy.

Neurobiology and Applications of Inositol in Psychiatry: A Narrative Review

Inositol is a natural sugar-like compound, commonly present in many plants and foods. It is involved in several biochemical pathways, most of them controlling vital cellular mechanisms, such as cell development, signaling and nuclear processes, metabolic and endocrine modulation, cell growth, signal transduction, etc. In this narrative review, we focused on the role of inositol in human brain physiology and pathology, with the aim of providing an update on both potential applications and current limits in its use in psychiatric disorders. Overall, imaging and biomolecular studies have shown the role of inositol levels in the pathogenesis of mood disorders. However, when administered as monotherapy or in addition to conventional drugs, inositol did not seem to influence clinical outcomes in both mood and psychotic disorders. Conversely, more encouraging results have emerged for the treatment of panic disorders. We concluded that, despite its multifaceted neurobiological activities and some positive findings, to date, data on the efficacy of inositol in the treatment of psychiatric disorders are still controversial, partly due to the heterogeneity of supporting studies. Therefore, systematic use of inositol in routine clinical practice cannot be recommended yet, although further basic and translational research should be encouraged.

Metabolic rewiring in MYC-driven medulloblastoma by BET-bromodomain inhibition

Medulloblastoma (MB) is the most common malignant brain tumour in children. High-risk MB patients harbouring MYC amplification or overexpression exhibit a very poor prognosis. Aberrant activation of MYC markedly reprograms cell metabolism to sustain tumorigenesis, yet how metabolism is dysregulated in MYC-driven MB is not well understood. Growing evidence unveiled the potential of BET-bromodomain inhibitors (BETis) as next generation agents for treating MYC-driven MB, but whether and how BETis may affect tumour cell metabolism to exert their anticancer activities remains unknown. In this study, we explore the metabolic features characterising MYC-driven MB and examine how these are altered by BET-bromodomain inhibition. To this end, we employed an NMR-based metabolomics approach applied to the MYC-driven MB D283 and D458 cell lines before and after the treatment with the BETi OTX-015. We found that OTX-015 triggers a metabolic shift in both cell lines resulting in increased levels of myo-inositol, glycerophosphocholine, UDP-N-acetylglucosamine, glycine, serine, pantothenate and phosphocholine. Moreover, we show that OTX-015 alters ascorbate and aldarate metabolism, inositol phosphate metabolism, phosphatidylinositol signalling system, glycerophospholipid metabolism, ether lipid metabolism, aminoacyl-tRNA biosynthesis, and glycine, serine and threonine metabolism pathways in both cell lines. These insights provide a metabolic characterisation of MYC-driven childhood MB cell lines, which could pave the way for the discovery of novel druggable pathways. Importantly, these findings will also contribute to understand the downstream effects of BETis on MYC-driven MB, potentially aiding the development of new therapeutic strategies to combat medulloblastoma.

Regulations of myo-inositol homeostasis: Mechanisms, implications, and perspectives

Phosphorylation is the most common module of cellular signalling pathways. The dynamic nature of phosphorylation, which is conferred by the balancing acts of kinases and phosphatases, allows this modification to finely control crucial cellular events such as growth, differentiation, and cell cycle progression. Although most research to date has focussed on protein phosphorylation, non-protein phosphorylation substrates also play vital roles in signal transduction. The most well-established substrate of non-protein phosphorylation is inositol, whose phosphorylation generates many important signalling molecules such as the second messenger IP₃, a key factor in calcium signalling. A fundamental question to our understanding of inositol phosphorylation is how the levels of cellular inositol are controlled. While the availability of protein phosphorylation substrates is known to be readily controlled at the levels of transcription, translation, and/or protein degradation, the regulatory mechanisms that control the uptake, synthesis, and removal of inositol are underexplored. Potentially, such mechanisms serve as an important layer of regulation of cellular signal transduction pathways. There are two ways in which mammalian cells acquire inositol. The historic use of radioactive ³H-myo-inositol revealed that inositol is promptly imported from the extracellular environment by three specific symporters SMIT1/2, and HMIT, coupling sodium or proton entry, respectively. Inositol can also be synthesized de novo from glucose-6P, thanks to the enzymatic activity of ISYNA1. Intriguingly, emerging evidence suggests that in mammalian cells, de novo myo-inositol synthesis occurs irrespective of inositol availability in the environment, prompting the question of whether the two sources of inositol go through independent metabolic pathways, thus serving distinct functions. Furthermore, the metabolic stability of myo-inositol, coupled with the uptake and endogenous synthesis, determines that there must be exit pathways to remove this extraordinary sugar from the cells to maintain its homeostasis. This essay aims to review our current knowledge of myo-inositol homeostatic metabolism, since they are critical to the signalling events played by its phosphorylated forms.

Physiological, Biochemical, and Structural Bioinformatic Analysis of the Multiple Inositol Dehydrogenases from Corynebacterium glutamicum

Inositols (cyclohexanehexols) comprise nine isomeric cyclic sugar alcohols, several of which occur in all domains of life with various functions. Many bacteria can utilize inositols as carbon and energy sources via a specific pathway involving inositol dehydrogenases (IDHs) as the first step of catabolism. The microbial cell factory Corynebacterium glutamicum can grow with myo-inositol as a sole carbon source. Interestingly, this species encodes seven potential IDHs, raising the question of the reason for this multiplicity. We therefore investigated the seven IDHs to determine their function, activity, and selectivity toward the biologically most important isomers myo-, scyllo-, and d-chiro-inositol. We created an ΔIDH strain lacking all seven IDH genes, which could not grow on the three inositols. scyllo- and d-chiro-inositol were identified as novel growth substrates of C. glutamicum. Complementation experiments showed that only four of the seven IDHs (IolG, OxiB, OxiD, and OxiE) enabled growth of the ΔIDH strain on two of the three inositols. The kinetics of the four purified enzymes agreed with the complementation results. IolG and OxiD are NAD⁺-dependent IDHs accepting myo- and d-chiro-inositol but not scyllo-inositol. OxiB is an NAD⁺-dependent myo-IDH with a weak activity also for scyllo-inositol but not for d-chiro-inositol. OxiE on the other hand is an NAD⁺-dependent scyllo-IDH showing also good activity for myo-inositol and a very weak activity for d-chiro-inositol. Structural models, molecular docking experiments, and sequence alignments enabled the identification of the substrate binding sites of the active IDHs and of residues allowing predictions on the substrate specificity. IMPORTANCE myo-, scyllo-, and d-chiro-inositol are C₆ cyclic sugar alcohols with various biological functions, which also serve as carbon sources for microbes. Inositol catabolism starts with an oxidation to keto-inositols catalyzed by inositol dehydrogenases (IDHs). The soil bacterium C. glutamicum encodes seven potential IDHs. Using a combination of microbiological, biochemical, and modeling approaches, we analyzed the function of these enzymes and identified four IDHs involved in the catabolism of inositols. They possess distinct substrate preferences for the three isomers, and modeling and sequence alignments allowed the identification of residues important for substrate specificity. Our results expand the knowledge of bacterial inositol metabolism and provide an important basis for the rational development of producer strains for these valuable inositols, which show pharmacological activities against, e.g., Alzheimer's disease, polycystic ovarian syndrome, or type II diabetes.

Synthesis and hydrolysis of monocarbamate from allylic 1,4-dicarbamate: Bis-homodichloroinositol

The synthesis of novel bis-homodichloroinositol with a configuration similar to that of conduritol-D is reported for the first time. The photooxygenation of cis-dichloro-diene obtained using cyclooctatetraene as the starting molecule afforted the tricyclic endoperoxide. The reduction of the endoperoxide with thiourea gave the corresponding allylic cis-diol. Formation of the bis-carbamate groups with p-TsNCO of allylic cis-diol followed by the [(dba)₃Pd₂CHCl₃] in the presence of trimethylsilyl azide, gave a new monocarbamate as well as oxazolidinone derivative. Oxidation of the double bond in the monocarbamate with osmium tetraoxide followed by acetylation furnished the desired monocarbamate triacetate. Eventually, the desired halogenated bicyclo[4.2.0] inositol (bis-homodichloroinositol) were obtained in high yield by hydrolysis of the acetate groups and monocarbanate group by potassium carbonate in methanol. Characterization of all the synthesized compounds were performed by FT-IR, ¹H NMR, ¹³C NMR, COSY (2D-NMR), HRMS, and Elemental Analysis techniques.

Site-selective C-H alkylation of myo-inositol via organic photoredox catalysis

Site-selective photoredox reactions with aromatic olefins enable direct alkylation of unprotected myo-inositol at C4. The efficacy of these reactions can be finely tuned by modifying the structures of HAT reagents. These reactions open the possibility of selective C-H alkylations of myo-inositol without the need for multi-step protection-deprotection strategies.

Stereoselective synthesis of novel bis-homoinositols with bicyclo[4.2.0]octane motifs

Starting from cyclooctatetraene, bis-homoconduritols with cis-inositol and allo-inositol (or bicyclo[4.2.0]octane motif) structures were synthesized. Photooxygenation of trans-7,8-dibromo-bicyclo[4.2.0]octa-2,4-diene allowed the preparation of tricyclic endoperoxide. The compound diacetate was obtained by reduction of endoperoxide with thiourea followed by acetylation reaction. Removal of halides with zinc dust in acetic acid yielded the dien-diacetate, a key compound of the designed molecules. OsO₄ oxidation of diendiacetate followed by acetylation gave the corresponding hexaacetates. Finally, the novel desired bis-homoinositols were obtained in high yield by the ammonolysis of acetate groups. The structures of all synthesized compounds were characterized by spectroscopic methods.

Nanostructured Layer of Silver for Detection of Small Biomolecules in Surface-Assisted Laser Desorption Ionization Mass Spectrometry

A facile approach for the synthesis of a silver nanostructured layer for application in surface-assisted laser desorption/ionization mass spectrometry of low-molecular-weight biomolecules was developed using electrochemical deposition. The deposition was carried out using the following silver salts: trifluoroacetate, acetate and nitrate, varying the voltage and time. The plate based on trifluoroacetate at 10 V for 15 min showed intense SALDI-MS responses for standards of various classes of compounds: fatty acids, cyclitols, saccharides and lipids at a concentration of 1 nmol/spot, with values of the signal-to-noise ratio ≥50. The values of the limit of detection were 0.71 µM for adonitol, 2.08 µM for glucose and 0.39 µM for palmitic acid per spot. SEM analysis of the plate showed anisotropic flower-like microstructures with nanostructures on their surface. The reduced chemical background in the low-mass region can probably be explained by the absence of stabilizers and reducing agents during the synthesis. The plate synthesized with the developed approach showed potential for future use in the analysis of low-molecular-weight compounds of biological relevance. The absence of the need for the utilization of sophisticated equipment and the synthesis time (10 min) may benefit large-scale applications of the layer for the detection of various types of small biomolecules.

Metabolic engineering of Pichia pastoris for myo-inositol production by dynamic regulation of central metabolism

BACKGROUND

The methylotrophic budding yeast Pichia pastoris GS115 is a powerful expression system and hundreds of heterologous proteins have been successfully expressed in this strain. Recently, P. pastoris has also been exploited as an attractive cell factory for the production of high-value biochemicals due to Generally Recognized as Safe (GRAS) status and high growth rate of this yeast strain. However, appropriate regulation of metabolic flux distribution between cell growth and product biosynthesis is still a cumbersome task for achieving efficient biochemical production.

RESULTS

In this study, P. pastoris was exploited for high inositol production using an effective dynamic regulation strategy. Through enhancing native inositol biosynthesis pathway, knocking out inositol transporters, and slowing down carbon flux of glycolysis, an inositol-producing mutant was successfully developed and low inositol production of 0.71 g/L was obtained. The inositol production was further improved by 12.7% through introduction of heterologous inositol-3-phosphate synthase (IPS) and inositol monophosphatase (IMP) which catalyzed the rate-limiting steps for inositol biosynthesis. To control metabolic flux distribution between cell growth and inositol production, the promoters of glucose-6-phosphate dehydrogenase (ZWF), glucose-6-phosphate isomerase (PGI) and 6-phosphofructokinase (PFK1) genes were replaced with a glycerol inducible promoter. Consequently, the mutant strain could be switched from growth mode to production mode by supplementing glycerol and glucose sequentially, leading to an increase of about 4.9-fold in inositol formation. Ultimately, the dissolved oxygen condition in high-cell-density fermentation was optimized, resulting in a high production of 30.71 g/L inositol (~ 40-fold higher than the baseline strain).

CONCLUSIONS

The GRAS P. pastoris was engineered as an efficient inositol producer for the first time. Dynamic regulation of cell growth and inositol production was achieved via substrate-dependent modulation of glycolysis and pentose phosphate pathways and the highest inositol titer reported to date by a yeast cell factory was obtained. Results from this study provide valuable guidance for engineering of P. pastoris for the production of other high-value bioproducts.

Comprehensive utilization of sucrose resources via chemical and biotechnological processes: A review

Sucrose, one of the most widespread disaccharides in nature, has been available in daily human life for many centuries. As an abundant and cheap sweetener, sucrose plays an essential role in our diet and the food industry. However, it has been determined that many diseases, such as obesity, diabetes, hyperlipidemia, etc., directly relate to the overconsumption of sucrose. It arouses many explorations for the conversion of sucrose to high-value chemicals. Production of valuable substances from sucrose by chemical methods has been studied since a half-century ago. Compared to chemical processes, biotechnological conversion approaches of sucrose are more environmentally friendly. Many enzymes can use sucrose as the substrate to generate functional sugars, especially those from GH68, GH70, GH13, and GH32 families. In this review, enzymatic catalysis and whole-cell fermentation of sucrose for the production of valuable chemicals were reviewed. The multienzyme cascade catalysis and metabolic engineering strategies were addressed.

Inositol depletion regulates phospholipid metabolism and activates stress signaling in HEK293T cells

Inositol plays a significant role in cellular function and signaling. Studies in yeast have demonstrated an "inositol-less death" phenotype, suggesting that inositol is an essential metabolite. In yeast, inositol synthesis is highly regulated, and inositol levels have been shown to be a major metabolic regulator, with its abundance affecting the expression of hundreds of genes. Abnormalities in inositol metabolism have been associated with several human disorders. Despite its importance, very little is known about the regulation of inositol synthesis and the pathways regulated by inositol in human cells. The current study aimed to address this knowledge gap. Knockout of ISYNA1 (encoding myo-inositol-3-P synthase 1) in HEK293T cells generated a human cell line that is deficient in de novo inositol synthesis. ISYNA1-KO cells exhibited inositol-less death when deprived of inositol. Lipidomic analysis identified inositol depletion as a global regulator of phospholipid levels in human cells, including downregulation of phosphatidylinositol (PI) and upregulation of the phosphatidylglycerol (PG)/cardiolipin (CL) branch of phospholipid metabolism. RNA-Seq analysis revealed that inositol depletion induced substantial changes in the expression of genes involved in cell signaling, including extracellular signal-regulated kinase (ERK), and genes controlling amino acid transport and protein processing in the endoplasmic reticulum (ER). This study provides the first in-depth characterization of the effects of inositol depletion on phospholipid metabolism and gene expression in human cells, establishing an essential role for inositol in maintaining cell viability and regulating cell signaling and metabolism.

Novel Chemical and Biological Insights of Inositol Derivatives in Mediterranean Plants

Inositols (Ins) are natural compounds largely widespread in plants and animals. Bio-sinthetically they derive from sugars, possessing a molecular structure very similar to the simple sugars, and this aspect concurs to define them as primary metabolites, even though it is much more correct to place them at the boundary between primary and secondary metabolites. This dichotomy is well represented by the fact that as primary metabolites they are essential cellular components in the form of phospholipid derivatives, while as secondary metabolites they are involved in a plethora of signaling pathways playing an important role in the surviving of living organisms. myo-Inositol is the most important and widespread compound of this family, it derives directly from d-glucose, and all known inositols, including stereoisomers and derivatives, are the results of metabolic processes on this unique molecule. In this review, we report the new insights of these compounds and their derivatives concerning their occurrence in Nature with a particular emphasis on the plant of the Mediterranean area, as well as the new developments about their biological effectiveness.

PCOS and Assisted Reproduction Technique: Role and Relevance of Inositols

Polycystic ovary syndrome is an endocrine disorder often characterized by insulin resistance and hyperinsulinemia, especially in overweight/obese women. Among insulin sensitizers, the positive role of inositols has been increasingly established in recent years. The action of inositols not only concerns the metabolic parameters of these patients, but also the hormonal profile, resulting in beneficial effects on ovarian function. For this reason, many studies have tried to recognize their role in PCOS infertile women who underwent in vitro fertilization (IVF) procedures.

gem-Heteroatom-Substituted Fluoroalkenes as Mimics of Amide Derivatives or Phosphates: A Comprehensive Review

gem-Heteroatom-substituted fluoroalkenes have received little attention despite their great potential in medicinal chemistry or in fine chemistry. Indeed, due to the electronic and steric similarity between the fluoroalkene moiety and the amide bond as well as the high strength of the carbon-fluorine bond, these gem-heteroatom-substituted fluoroalkenes could be envisioned as stable mimics of various important organic functions, such as phosphates, carbamates, S-thiocarbamates and ureas. We present herein an overview describing the syntheses over the last decade of heteroatom-substituted fluoroalkenes in geminal position. This review will be divided into several sections covering each the common following heteroatom: oxygen-, nitrogen-, sulfur-, phosphorus-, boron- and silicon-substituted fluoroalkenes.

Lost in Condensation: Poly-, Cyclo-, and Ultraphosphates

Much like linear, branched, and cyclic alkanes, condensed phosphates exist as linear, branched, and cyclic structures. Inasmuch as alkanes are the cornerstone of organic chemistry, generating an inexplorably large chemical space, a comparable richness in structures can be expected for condensed phosphates, as also for them the concepts of isomerism apply. Little of their chemical space has been charted, and only a few different synthesis methods are available to construct isomers of condensed phosphates. Here, we will discuss the application of phosphoramidites with one, two, or three P-N bonds that can be substituted selectively to access different condensed phosphates in a highly controllable manner. Work directed toward the further exploration of this chemical space will contribute to our understanding of the fundamental chemistry of phosphates.In biology, condensed phosphates play important roles in the form of inorganic representatives, such as pyrophosphate, polyphosphate, and cyclophosphate, and also in conjugation with organic molecules, such as esters and amidates. Phosphorus is one of the six biogenic elements; the omnipresence of phosphates in biology points toward their critical involvement in prebiotic chemistry and the emergence of life itself. Indeed, it is hard to imagine any life without phosphate. It is therefore desirable to achieve through synthesis a better understanding of the chemistry of the condensed phosphates to further explore their biology.There is a rich but underexplored chemistry of the family of condensed phosphates per se, which is further diversified by their conjugation to important biomolecules and metabolites. For example, proteins may be polyphosphorylated on lysins, a very recent addition to posttranslational modifications. Adenosine triphosphate, as a representative of the small molecules, on the other hand, is well known as the universal cellular energy currency. In this Account, we will describe our motivations and our approaches to construct, modify, and synthetically apply different representatives of the condensed phosphates. We also describe the generation of hybrids composed of cyclic and linear structures of different oxidation states and develop them into reagents of great utility. A pertinent example is provided in the step-economic synthesis of the magic spot nucleotides (p)ppGpp. Finally, we provide an overview of ³¹P NMR data collected over the years in our laboratories, helping as a waymarker for not getting lost in condensation.

Efficient genome editing in filamentous fungi via an improved CRISPR-Cas9 ribonucleoprotein method facilitated by chemical reagents

DNA double-strand break (DSB) repair induced by the RNA-programmed nuclease Cas9 has become a popular method for genome editing. Direct genome editing via Cas9-CRISPR gRNA (guide RNA) ribonucleoprotein (RNP) complexes assembled in vitro has also been successful in some fungi. However, the efficiency of direct RNP transformation into fungal protoplasts is currently too low. Here, we report an optimized genome editing approach for filamentous fungi based on RNPs facilitated by adding chemical reagents. We increased the transformation efficiency of RNPs significantly by adding Triton X-100 and prolonging the incubation time, and the editing efficiency reached 100% in Trichoderma reesei and Cordyceps militaris. The optimized RNP-based method also achieved efficient (56.52%) homologous recombination integration with short homology arms (20 bp) and gene disruption (7.37%) that excludes any foreign DNA (selection marker) in T. reesei. In particular, after adding reagents related to mitosis and cell division, the further optimized protocol showed an increased ratio of edited homokaryotic transformants (from 0% to 40.0% for inositol and 71.43% for benomyl) from Aspergillus oryzae, which contains multinucleate spores and protoplasts. Furthermore, the multi-target engineering efficiency of the optimized RNP transformation method was similar to those of methods based on in vivo expression of Cas9. This newly established genome editing system based on RNPs may be widely applicable to construction of genome-edited fungi for the food and medical industries, and has good prospects for commercialization.

Fertility-Sparing Approach in Women Affected by Stage I and Low-Grade Endometrial Carcinoma: An Updated Overview

Endometrial cancer (EC) is a deleterious condition which strongly affects a woman's quality of life. Although aggressive interventions should be considered to treat high-grade EC, a conservative approach should be taken into consideration for women wishing to conceive. In this scenario, we present an overview about the EC fertility-sparing approach state of art. Type I EC at low stage is the only histological type which can be addressed with a fertility-sparing approach. Moreover, no myometrium and/or adnexal invasion should be seen, and lymph-vascular space should not be involved. Regarding the pharmaceutical target, progestins, in particular medroxyprogesterone acetate (MPA) or megestrol acetate (MA), are the most employed agent in conservative treatment of early-stage EC. The metformin usage and hysteroscopic assessment is still under debate, despite promising results. Particularly strict and imperious attention should be given to the follow-up and psychological wellbeing of women, especially because of the double detrimental impairment: both EC and EC-related infertility consequences.

Single-crystal-to-single-crystal synthesis of a pseudostarch via topochemical azide-alkyne cycloaddition polymerization

There is high demand for polysaccharide-mimics as enzyme-stable substitutes for polysaccharides for various applications. Circumventing the problems associated with the solution-phase synthesis of such polymers, we report here the synthesis of a crystalline polysaccharide-mimic by topochemical polymerization. By crystal engineering, we designed a topochemically reactive crystal of a glucose-mimicking monomer decorated with azide and alkyne units. In the crystal, the monomers arrange in head-to-tail fashion with their azide and alkyne groups in a ready-to-react antiparallel geometry, suitable for their topochemical azide-alkyne cycloaddition (TAAC) reaction. On heating the crystals, these pre-organized monomer molecules undergo regiospecific TAAC polymerization, yielding 1,4-triazolyl-linked pseudopolysaccharide (pseudostarch) in a single-crystal-to-single-crystal manner. This crystalline pseudostarch shows better thermal stability than its amorphous form and many natural polysaccharides.

Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiae

BACKGROUND

Myo-Inositol Phosphate Synthase (MIP) catalyzes the conversion of glucose 6- phosphate into inositol phosphate, an essential nutrient and cell signaling molecule. Data obtained, first in bovine brain and later in plants, established MIP expression in organelles and in extracellular environments. A physiological role for secreted MIP has remained elusive since its first detection in intercellular space. To provide further insight into the role of MIP in intercellular milieus, we tested the hypothesis that MIP may function as a growth factor, synthesizing inositol phosphate in intercellular locations requiring, but lacking ability to produce or transport adequate quantities of the cell-cell communicator. This idea was experimentally challenged, utilizing a Saccharomyces cerevisiae inositol auxotroph with no MIP enzyme, permeable membranes with a 0.4 µm pore size, and cellular supernatants as external sources of inositol isolated from S. cerevisiae cells containing either wild-type enzyme (Wt-MIP), no MIP enzyme, auxotroph (Aux), or a green fluorescent protein (GFP) tagged reporter enzyme (MIP- GFP) in co- culturing experiments.

RESULTS

Resulting cell densities and microscopic studies with corroborating biochemical and molecular analyses, documented sustained growth of Aux cells in cellular supernatant, concomitant with the uptakeof MIP, detected as MIP-GFP reporter enzyme. These findings revealed previously unknown functions, suggesting that the enzyme can: (1) move into and out of intercellular space, (2) traverse cell walls, and (3) act as a growth factor to promote cellular proliferation of an inositol requiring cell.

CONCLUSIONS

Co-culturing experiments, designed to test a probable function for MIP secreted in extracellular vesicles, uncovered previously unknown functions for the enzyme and advanced current knowledge concerning spatial control of inositol phosphate biosynthesis. Most importantly, resulting data identified an extracellular vesicle (a non-viral vector) that is capable of synthesizing and transporting inositol phosphate, a biological activity that can be used to enhance specificity of current inositol phosphate therapeutics.

Novel Substrates for Kinases Involved in the Biosynthesis of Inositol Pyrophosphates and Their Enhancement of ATPase Activity of a Kinase

IP6K and PPIP5K are two kinases involved in the synthesis of inositol pyrophosphates. Synthetic analogs or mimics are necessary to understand the substrate specificity of these enzymes and to find molecules that can alter inositol pyrophosphate synthesis. In this context, we synthesized four scyllo-inositol polyphosphates-scyllo-IP₅, scyllo-IP₆, scyllo-IP₇ and Bz-scyllo-IP₅-from myo-inositol and studied their activity as substrates for mouse IP6K1 and the catalytic domain of VIP1, the budding yeast variant of PPIP5K. We incubated these scyllo-inositol polyphosphates with these kinases and ATP as the phosphate donor. We tracked enzyme activity by measuring the amount of radiolabeled scyllo-inositol pyrophosphate product formed and the amount of ATP consumed. All scyllo-inositol polyphosphates are substrates for both the kinases but they are weaker than the corresponding myo-inositol phosphate. Our study reveals the importance of axial-hydroxyl/phosphate for IP6K1 substrate recognition. We found that all these derivatives enhance the ATPase activity of VIP1. We found very weak ligand-induced ATPase activity for IP6K1. Benzoyl-scyllo-IP₅ was the most potent ligand to induce IP6K1 ATPase activity despite being a weak substrate. This compound could have potential as a competitive inhibitor.

NMR-Based Lipid Metabolite Profiles to Predict Outcomes in Patients Undergoing Interventional Therapy for a Hepatocellular Carcinoma (HCC): A Substudy of the SORAMIC Trial

Simple Summary

A hepatocellular carcinoma (HCC) is the most common cause of death in patients suffering from chronic liver diseases. In order to improve the prediction of outcomes in HCC patients, there is a need for new biomarkers. This pilot study aimed at identifying serum metabolites for the prediction of outcomes of HCC patients using nuclear magnetic resonance (NMR) spectroscopy. This analysis revealed that high serum concentrations of myo-inositol or dimethylamine were associated with an improved overall survival. In contrast, high concentrations of total cholesterol, LDL-cholesterol and LDL particles (LDL-P) were associated with a decreased overall survival. The identification of novel biomarkers using this NMR-based technology holds promise for opening new directions in the conduction of interventional trials in HCCs.

Abstract

Background: This exploratory study aimed to evaluate lipidomic and metabolomic profiles in patients with early and advanced HCCs and to investigate whether certain metabolic parameters may predict the overall survival in these patients. Methods: A total of 60 patients from the prospective, randomized-controlled, multicenter phase II SORAMIC trial were included in this substudy; among them were 30 patients with an early HCC who underwent radiofrequency ablation combined with sorafenib or a placebo and 30 patients with an advanced HCC who were treated with a selective internal radiation therapy (SIRT) plus sorafenib vs. sorafenib alone. The blood serum of these patients was analyzed using a standardized nuclear magnetic resonance (NMR) platform. All tested metabolites were correlated with the overall survival. Results: The overall survival (OS) was significantly higher in patients with an early HCC (median OS: 34.0 months) compared with patients with an advanced HCC (median OS: 12.0 months) (p < 0.0001). Patients with high serum concentrations of myo-inositol (MI) had a higher overall survival compared with patients with low concentrations (21.6 vs. 13.8 months) with a Pearson correlation coefficient of 0.331 (p = 0.011). Patients with high serum concentrations of dimethylamine had a higher overall survival compared with patients with low concentrations (25.1 vs. 19.7 months) with a Pearson correlation coefficient of 0.279 (p = 0.034). High concentrations of total cholesterol, LDL-cholesterol and LDL particles (LDL-P) were associated with a decreased overall survival. Conclusions: NMR-based lipidomic and metabolomic profiling has the potential to identify individual metabolite biomarkers that predict the outcome of patients with an HCC exposed to non-invasive therapeutic management.

Integrated metabolomic analysis and cytokine profiling define clusters of immuno-metabolic correlation in new-onset psoriasis

The association between the metabolic profile and inflammatory cytokines in psoriasis is poorly understood. We analyzed the metabolic and cytokine/chemokine profiles in serum and skin from patients with new-onset psoriasis and healthy subjects (n = 7/group) by HR-MAS NMR and Bio-Plex immunoassay. Immuno-metabolic correlation matrix was analyzed in skin and serum to identify a potential immune-metabolic signature. Metabolomics analysis showed a significant increase in ascorbate and a decrease in scyllo-inositol, and a trend towards an increase in eight other metabolites in psoriatic skin. In serum, there was a significant increase of dimethylglycine and isoleucine. In parallel, psoriatic skin exhibited an increase of early inflammatory cytokines (IL-6, IL-8, TNF-α, IL-1β) and correlation analysis highlighted some major clusters of immune-metabolic correlations. A cluster comprising scyllo-inositol and lysine showed correlations with T-cell cytokines; a cluster comprising serine and taurine showed a negative correlation with early inflammatory cytokines (IL-6, G-CSF, CCL3). A strong positive correlation was enlightened between glutathione and inflammatory cytokines/angiogenesis promoters of psoriasis. The integration of metabolic and immune data indicated a molecular signature constituted by IL-6, IL1-ra, DMG, CCL4, Ile, Gly and IL-8, which could discriminate patients and healthy subjects and could represent a candidate tool in the diagnosis of new-onset psoriasis.

Production of myo-inositol: Recent advance and prospective

Myo-inositol and its derivatives have been extensively used in the pharmaceutics, cosmetics, and food and feed industries. In recent years, compared with traditional chemical acid hydrolysis, biological methods have been taken as viable and cost-effective ways to myo-inositol production from cheap raw materials. In this review, we provide a thorough overview of the development, progress, current status, and future direction of myo-inositol production (e.g., chemical acid hydrolysis, microbial fermentation, and in vitro enzymatic biocatalysis). The chemical acid hydrolysis of phytate suffers from serious phosphorous pollution and intricate product separation, resulting in myo-inositol production at a high cost. For microbial fermentation, creative strategies have been provided for the efficient myo-inositol biosynthesis by synergetic utilization of glucose and glycerol in Escherichia coli. In vitro cascade enzymatic biocatalysis is a multienzymatic transformation of various substrates to myo-inositol. Here, the different in vitro pathways design, the source of selected enzymes, and the catalytic condition optimization have been summarized and analyzed. Also, we discuss some important existing challenges and suggest several viewpoints. The development of in vitro enzymatic biosystems featuring low cost, high volumetric productivity, flexible compatibility, and great robustness could be one of the promising strategies for future myo-inositol industrial biomanufacturing.

Allosteric Site on SHIP2 Identified Through Fluorescent Ligand Screening and Crystallography: A Potential New Target for Intervention

Src homology 2 domain-containing inositol phosphate phosphatase 2 (SHIP2) is one of the 10 human inositol phosphate 5-phosphatases. One of its physiological functions is dephosphorylation of phosphatidylinositol 3,4,5-trisphosphate, PtdIns(3,4,5)P₃. It is therefore a therapeutic target for pathophysiologies dependent on PtdIns(3,4,5)P₃ and PtdIns(3,4)P₂. Therapeutic interventions are limited by the dearth of crystallographic data describing ligand/inhibitor binding. An active site-directed fluorescent probe facilitated screening of compound libraries for SHIP2 ligands. With two additional orthogonal assays, several ligands including galloflavin were identified as low micromolar Ki inhibitors. One ligand, an oxo-linked ethylene-bridged dimer of benzene 1,2,4-trisphosphate, was shown to be an uncompetitive inhibitor that binds to a regulatory site on the catalytic domain. We posit that binding of ligands to this site restrains L4 loop motions that are key to interdomain communications that accompany high catalytic activity with phosphoinositide substrate. This site may, therefore, be a future druggable target for medicinal chemistry.

A dansyl-derivatized phytic acid analogue as a fluorescent substrate for phytases: experimental and computational approach

A new myo-inositol pentakisphosphate was synthesized, which featured a dansyl group at position C-5. The fluorescent tag was removed from the inositol by a 6-atom spacer to prevent detrimental steric interactions in the catalytic site of phytases. The PEG linker was used in order to enhance hydrophilicity and biocompatibility of the new artificial substrate. Computational studies showed a favorable positioning in the catalytic site of phytases. Enzymatic assays demonstrated that the tethered myo-inositol was processed by two recombinant phytases Phy-A and Phy-C, classified respectively as acid and alkaline phytases, with similar rates of phosphate release compared to their natural substrate.

Preparation of pure lower-order myo-Inositol phosphates on laboratory scale for physiological and enzymatic studies

A simple method for the preparative production of lower-order myo-inositol phosphates was developed. Enzymatic phytate dephosphorylation was applied, because phytate-degrading enzymes generate usually predominantly one single myo-inositol phosphate isomer with five, four, three, two and one phosphate residue(s) bound to the myo-inositol ring in a regio- and stereoselective manner. The relative concentrations of the different lower-order myo-inositol phosphates in the reaction mixture were controlled by adjusting incubation time at 37 °C and a fixed phytate concentration and phytase activity. Purification of the individual lower-order myo-inositol phosphates was realized by anion-exchange chromatography on Q-Sepharose using a stepwise elution with ammonium formate:formic acid pH 2.5. Ethanol precipitation was successfully used to concentrate the pure lower-order myo-inositol phosphates. In a single approach 2-3 mg of pure myo-inositol tetrakis- or -trisphosphate isomers were obtained. About 60% of the initially applied phytate were converted into pure lower-order myo-inositol phosphates. The purified myo-inositol phosphate isomers were virtually free of other myo-inositol phosphate esters and could be used for enzymatic and physiological studies.

Snapshots of "crystalline" salt-water solutions of inositol hexaphosphate conformers

Supramolecular insight to intra- and inter-ionic interactions in two inositol hexaphosphate conformers as a function of pH was enabled by NMR and crystallographic studies. These findings also shed light on the complex interactive roles of extended salt-water arrays through the crystal "solution" lattice.

D-Chiro-Inositol Regulates Insulin Signaling in Human Adipocytes

D-Chiro-Inositol (D-Chiro-Ins) is a secondary messenger in the insulin signaling pathway. D-Chiro-Ins modulates insulin secretion, the mitochondrial respiratory chain, and glycogen storage. Due to these actions D-Chiro-Ins has been proposed to correct defective insulin function in a variety of conditions characterized by metabolic dysfunction, such as polycystic ovary syndrome (PCOS), obesity, gestational diabetes and fat accumulation at menopause. Since it is unclear whether D-Chiro-Ins directly acts on adipocytes, we aimed to study D-Chiro-Ins's actions on adipocyte viability, proliferation, differentiation, and insulin-related protein expression using a human adipocyte cell line derived from Simpson-Golabi-Behmel Syndrome (SGBS) which fully differentiates to mature adipocytes. Throughout differentiation, cells were treated with D-Chiro-Ins, 17β-estradiol (E2) or Insulin. Cell viability and proliferation were not affected by D-Chiro-Ins, then D-Chiro-Ins promoted cell differentiation only during the final days of the process, while E2 enhanced it from the first phases. D-Chiro-Ins stimulated lipid storage and the production of big lipid droplets, thus reducing the content of free fatty acids. We also found that D-Chiro-Ins, either alone or in combination with insulin and E2 increased the expression and activation of insulin receptor substrate-1 (IRS1) and glucose transporter type 4 (GLUT4). In conclusion, this work shows that D-Chiro-Ins plays a direct role in the differentiation and in the function of human adipocytes, where it synergizes with insulin and estrogen through the recruitment of signal transduction pathways involved in lipid and glucose storage. These findings give clear insights to better understand the actions of D-Chiro-Ins on fat metabolism in women in physiology and in a variety of diseases.

Differential Gene Expression and Biological Analyses of Primary Hepatocytes Following D-Chiro-Inositol Supplement

Dietary supplements have improved the prevention of insulin resistance and metabolic diseases, which became a research hotspot in food science and nutrition. Obesity and insulin resistance, caused by a high-fat diet, eventually result in severe metabolic diseases, can be prevented with the dietary supplement D-chiro-inositol (DCI). In this work, we isolated mice primary hepatocytes with palmitic acid stimulation and DCI was applied to compare and contrast its effects of in primary hepatocyte biology. Before and after intervention with DCI, we used RNA-Seq technology to establish a primary hepatocyte transcriptome gene profile. We found that both PA and DCI cause a wide variation in gene expression. Particularly, we found that DCI plays critical role in this model by acting on glycolysis and gluconeogenesis. Overall, we generated extensive transcripts from primary hepatocytes and uncovered new functions and gene targets for DCI.

Inositol Hexaphosphate (IP6) and Colon Cancer: From Concepts and First Experiments to Clinical Application

Multiple human health-beneficial effects have been related to highly phosphorylated inositol hexaphosphate (IP6). This naturally occurring carbohydrate and its parent compound, myo-inositol (Ins), are abundantly present in plants, particularly in certain high-fiber diets, but also in mammalian cells, where they regulate important cellular functions. However, the striking and broad-spectrum anticancer activity of IP6, consistently demonstrated in different experimental models, has been in a spotlight of the scientific community dealing with the nutrition and cancer during the last several decades. First experiments were performed in colon cancer 30 years ago. Since then, it has been shown that IP6 reduces cell proliferation, induces apoptosis and differentiation of malignant cells with reversion to normal phenotype, affecting several critical molecular targets. Enhanced immunity and antioxidant properties also contribute to the tumor cell destruction. Although Ins possesses a modest anticancer potential, the best anticancer results were obtained from the combination of IP6 + Ins. Here we review the first experimental steps in colon cancer, when concepts and hypotheses were put together almost without real knowledge and present clinical studies, that were initiated in colon cancer patients. Available as a dietary supplement, IP6 + Ins has been shown to enhance the anticancer effect of conventional chemotherapy, controls cancer metastases, and improves quality of life in cancer patients. Emerging clinical and still vast amount of experimental data suggest its role either as an adjuvant or as an "alternative" to current chemotherapy for cancer.