Regulation of Mitochondrial Respiration by VDAC Is Enhanced by Membrane-Bound Inhibitors with Disordered Polyanionic C-Terminal Domains

The voltage-dependent anion channel (VDAC) is the primary regulating pathway of water-soluble metabolites and ions across the mitochondrial outer membrane. When reconstituted into lipid membranes, VDAC responds to sufficiently large transmembrane potentials by transitioning to gated states in which ATP/ADP flux is reduced and calcium flux is increased. Two otherwise unrelated cytosolic proteins, tubulin, and α-synuclein (αSyn), dock with VDAC by a novel mechanism in which the transmembrane potential draws their disordered, polyanionic C-terminal domains into and through the VDAC channel, thus physically blocking the pore. For both tubulin and αSyn, the blocked state is observed at much lower transmembrane potentials than VDAC gated states, such that in the presence of these cytosolic docking proteins, VDAC’s sensitivity to transmembrane potential is dramatically increased. Remarkably, the features of the VDAC gated states relevant for bioenergetics—reduced metabolite flux and increased calcium flux—are preserved in the blocked state induced by either docking protein. The ability of tubulin and αSyn to modulate mitochondrial potential and ATP production in vivo is now supported by many studies. The common physical origin of the interactions of both tubulin and αSyn with VDAC leads to a general model of a VDAC inhibitor, facilitates predictions of the effect of post-translational modifications of known inhibitors, and points the way toward the development of novel therapeutics targeting VDAC.

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Role of Nicotinamide in DNA Damage, Mutagenesis, and DNA Repair

Journal of Nucleic Acids ◽

10.4061/2010/157591 ◽

2010 ◽

Vol 2010 ◽

pp. 1-13 ◽

Cited By ~ 89

Author(s):

Devita Surjana ◽

Gary M. Halliday ◽

Diona L. Damian

Keyword(s):

Dna Repair ◽

Cellular Responses ◽

Water Soluble ◽

Vitamin B3 ◽

Atp Production ◽

Amide Form ◽

Parp 1

Nicotinamide is a water-soluble amide form of niacin (nicotinic acid or vitamin B3). Both niacin and nicotinamide are widely available in plant and animal foods, and niacin can also be endogenously synthesized in the liver from dietary tryptophan. Nicotinamide is also commercially available in vitamin supplements and in a range of cosmetic, hair, and skin preparations. Nicotinamide is the primary precursor of nicotinamide adenine dinucleotide (NAD+), an essential coenzyme in ATP production and the sole substrate of the nuclear enzyme poly-ADP-ribose polymerase-1 (PARP-1). Numerousin vitroandin vivostudies have clearly shown that PARP-1 and NAD+status influence cellular responses to genotoxicity which can lead to mutagenesis and cancer formation. This paper will examine the role of nicotinamide in the protection from carcinogenesis, DNA repair, and maintenance of genomic stability.

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Bicalutamide Elicits Renal Damage by Causing Mitochondrial Dysfunction via ROS Damage and Upregulation of HIF-1

International Journal of Molecular Sciences ◽

10.3390/ijms21093400 ◽

2020 ◽

Vol 21 (9) ◽

pp. 3400

Author(s):

Kuan-Chou Chen ◽

Chang-Rong Chen ◽

Chang-Yu Chen ◽

Kai-Yi Tzou ◽

Chiung-Chi Peng ◽

...

Keyword(s):

Messenger Rna ◽

Renal Damage ◽

Mesangial Cells ◽

Cell Model ◽

Hypoxia Inducible Factor ◽

Kidney Injury ◽

Mitochondrial Potential ◽

Interacting Protein ◽

Atp Production

Combined androgen blockade using bicalutamide (Bic) is a therapeutic choice for treating prostate cancer (PCa). However, even at regular clinical dosages, Bic frequently shows adverse effects associated with cardiovascular and renal damage. Previously, we found that Bic selectively damaged mesangial cells compared to tubular cells and in an in vivo rat model, we also found renal damage caused by Bic. In the present study, a rat mesangial cell model was used to further the investigation. Results indicated that Bic enhanced lactate dehydrogenase release, reactive oxygen species (ROS) production, lysosome population and kidney injury molecule-1 and decreased N-cadherin. Bic elicited mitochondrial swelling and reduced the mitochondrial potential, resulting in severe suppression of the oxygen consumption rate (OCR), maximum respiration and ATP production. The hypoxia-inducible factor (HIF)-1 transcriptional activity and messenger RNA were significantly upregulated in dose-dependent manners. The HIF-1 protein reached a peak value at 24 h then rapidly decayed. BCL2/adenovirus E1B 19-kDa protein-interacting protein 3 and cleaved caspase-3 were dose-dependently upregulated by Bic (60 M) and that eventually led to cell apoptosis. It is suggested that Bic induces renal damage via ROS and modulates HIF-1 pathway and clinically, some protective agents like antioxidants are recommended for co-treatment.

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The Open State Selectivity of the Bean Seed VDAC Depends on Stigmasterol and Ion Concentration

International Journal of Molecular Sciences ◽

10.3390/ijms22063034 ◽

2021 ◽

Vol 22 (6) ◽

pp. 3034

Author(s):

Hayet Saidani ◽

Marc Léonetti ◽

Hanna Kmita ◽

Fabrice Homblé

Keyword(s):

Physiological Role ◽

Anion Channel ◽

Physiological Effect ◽

Ion Concentration ◽

Mitochondrial Outer Membrane ◽

Voltage Dependent Anion Channel ◽

Major Pathway ◽

Voltage Dependent ◽

State Selectivity

The voltage-dependent anion channel (VDAC) is the major pathway for metabolites and ions transport through the mitochondrial outer membrane. It can regulate the flow of solutes by switching to a low conductance state correlated with a selectivity reversal, or by a selectivity inversion of its open state. The later one was observed in non-plant VDACs and is poorly characterized. We aim at investigating the selectivity inversion of the open state using plant VDAC purified from Phaseolus coccineus (PcVDAC) to evaluate its physiological role. Our main findings are: (1) The VDAC selectivity inversion of the open state occurs in PcVDAC, (2) Ion concentration and stigmasterol affect the occurrence of the open state selectivity inversion and stigmasterol appears to interact directly with PcVDAC. Interestingly, electrophysiological data concerning the selectivity inversion of the PcVDAC open state suggests that the phenomenon probably does not have a significant physiological effect in vivo.

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The Oral Intake of Organic Germanium, Ge-132, Elevates α-Tocopherol Levels in the Plas-ma and Modulates Hepatic Gene Expression Profiles to Promote Immune Activation in Mice

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000205 ◽

2014 ◽

Vol 84 (3-4) ◽

pp. 0183-0195 ◽

Cited By ~ 12

Author(s):

Takashi Nakamura ◽

Tomoya Takeda ◽

Yoshihiko Tokuji

Keyword(s):

Gene Expression ◽

Immune Activation ◽

Expression Profiles ◽

Water Soluble ◽

Alpha Tocopherol ◽

Hepatic Gene Expression ◽

Tocopherol Concentration ◽

Altered Expression ◽

Atp Production ◽

Transfer Protein

The common water-soluble organic germanium compound poly-trans-[(2-carboxyethyl) germasesquioxane] (Ge-132) exhibits activities related to immune responses and antioxidant induction. In this study, we evaluated the antioxidative effect of dietary Ge-132 in the plasma of mice. Male ICR mice (seven mice per group) received an AIN-76 diet with 0.05 % Ge-132; three groups received the Ge-132-containing diet for 0, 1 or 4 days. The plasma alpha-tocopherol (α-tocopherol) concentration increased from 6.85 to 9.60 μg/ml after 4 days of Ge-132 intake (p < 0.05). We evaluated the changes in hepatic gene expression related to antioxidative activity as well as in the entire expression profile after one day of Ge-132 intake, using DNA microarray technology. We identified 1,220 genes with altered expression levels greater than 1.5-fold (increased or decreased) as a result of Ge-132 intake, and α-tocopherol transfer protein (Ttpa) gene expression was increased 1.62-fold. Immune activation was identified as the category with the most changes (containing 60 Gene Ontology (GO) term biological processes (BPs), 41 genes) via functional clustering analysis of altered gene expression. Ge-132 affected genes in clusters related to ATP production (22 GO term BPs, 21 genes), lipid metabolism (4 GO term BPs, 38 genes) and apoptosis (5 GO term BPs). Many GO term BPs containing these categories were significantly affected by the Ge-132 intake. Oral Ge-132 intake may therefore have increased plasma α-tocopherol levels by up-regulating α-tocopherol transfer protein (Ttpa) gene expression.

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Fenofibrate Solid Dispersion for Improving Oral Bioavailability: Preparation, and Characterization and in vivo Evaluation

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2020.13.5.7 ◽

2020 ◽

Vol 13 (5) ◽

pp. 5102-5109

Author(s):

Venu Madhav K ◽

Somnath De ◽

Chandra Shekar Bonagiri ◽

Sridhar Babu Gummadi

Keyword(s):

Oral Bioavailability ◽

Oral Delivery ◽

Solid Dispersions ◽

In Vitro Release ◽

Aqueous Solubility ◽

Water Soluble ◽

Scanning Calorimetry ◽

In Vivo Evaluation

Fenofibrate (FN) is used in the treatment of hypercholesterolemia. It shows poor dissolution and poor oral bioavailability after oral administration due to high liphophilicity and low aqueous solubility. Hence, solid dispersions (SDs) of FN (FN-SDs) were develop that might enhance the dissolution and subsequently oral bioavailability. FN-SDs were prepared by solvent casting method using different carriers (PEG 4000, PEG 6000, β cyclodextrin and HP β cyclodextrin) in different proportions (0.25%, 0.5%, 0.75% and 1% w/v). FN-SDs were evaluated solubility, assay and in vitro release studies for the optimization of SD formulation. Differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM) analysis was performed for crystalline and morphology analysis, respectively. Further, optimized FN-SD formulation evaluated for pharmacokinetic performance in Wistar rats, in vivo in comparison with FN suspension. From the results, FN-SD3 and FN-SD6 have showed 102.9 ±1.3% and 105.5±3.1% drug release, respectively in 2 h. DSC and PXRD studies revealed that conversion of crystalline to amorphous nature of FN from FT-SD formulation. SEM studies revealed the change in the orientation of FN when incorporated in SDs. The oral bioavailability FN-SD3 and FN-SD6 formulations exhibited 2.5-folds and 3.1-folds improvement when compared to FN suspension as control. Overall, SD of FN could be considered as an alternative dosage form for the enhancement of oral delivery of poorly water-soluble FN.

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Chemosensitizing Activity of Histone Deacetylases Inhibitory Cyclic Hydroxamic Acids for Combination Chemotherapy of Lymphatic Leukemia

Current Cancer Drug Targets ◽

10.2174/1568009617666170623104030 ◽

2018 ◽

Vol 18 (4) ◽

pp. 365-371 ◽

Cited By ~ 2

Author(s):

Denis V. Mishchenko ◽

Margarita E. Neganova ◽

Elena N. Klimanova ◽

Tatyana E. Sashenkova ◽

Sergey G. Klochkov ◽

...

Keyword(s):

Lipid Peroxidation ◽

Acute Toxicity ◽

Histone Deacetylases ◽

Hydroxamic Acids ◽

Water Soluble ◽

Male Rat ◽

Hybrid Male ◽

Cyclic Hydroxamic Acids

Background: Anti-tumor effect of hydroxamic acid derivatives is largely connected with its properties as efficient inhibitors of histone deacetylases, and other metalloenzymes involved in carcinogenesis. Objective: The work was aimed to (i) determine the anti-tumor and chemosensitizing activity of the novel racemic spirocyclic hydroxamic acids using experimental drug sensitive leukemia P388 of mice, and (ii) determine the structure-activity relationships as metal chelating and HDAC inhibitory agents. Method: Outbreed male rat of 200-220 g weights were used in biochemical experiments. In vivo experiments were performed using the BDF1 hybrid male mice of 22-24 g weight. Lipid peroxidation, Fe (II) -chelating activity, HDAC fluorescent activity, anti-tumor and anti-metastatic activity, acute toxicity techniques were used in this study. Results: Chemosensitizing properties of water soluble cyclic hydroxamic acids (CHA) are evaluated using in vitro activities and in vivo methods and found significant results. These compounds possess iron (II) chelating properties, and slightly inhibit lipid peroxidation. CHA prepared from triacetonamine (1a-e) are more effective Fe (II) ions cheaters, as compared to CHA prepared from 1- methylpiperidone (2a-e). The histone deacetylase (HDAC) inhibitory activity, lipophilicity and acute toxicity were influenced by the length amino acids (size) (Glycine < Alanine < Valine < Leucine < Phenylalanine). All compounds bearing spiro-N-methylpiperidine ring (2a-e) are non-toxic up to 1250 mg/kg dose, while compounds bearing spiro-tetramethylpiperidine ring (1a-e) exhibit moderate toxicity which increases with increasing lipophility, but not excite at 400 mg/kg. Conclusion: It was shown that the use of combination of non-toxic doses of cisplatin (cPt) or cyclophosphamide with CHA in most cases result in the appearance of a considerable anti-tumor effect of cytostatics. The highest chemosensitizing activity with respect to leukemia Р388 is demonstrated by the CHA derivatives of Valine 1c or 2c.

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Development, Characterization and In Vivo Pharmacokinetic Assessment of Rectal Suppositories Containing Combination Antiretroviral Drugs for HIV Prevention

Pharmaceutics ◽

10.3390/pharmaceutics13081110 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1110

Author(s):

Kunal Jhunjhunwala ◽

Charles W. Dobard ◽

Sunita Sharma ◽

Natalia Makarova ◽

Angela Holder ◽

...

Keyword(s):

Hiv Prevention ◽

Antiretroviral Drugs ◽

Water Soluble ◽

Fixed Dose ◽

Receptive Anal Intercourse ◽

On Demand ◽

Dose Combination ◽

Rectal Suppositories

Receptive anal intercourse (RAI) contributes significantly to HIV acquisition underscoring the need to develop HIV prevention options for populations engaging in RAI practices. We explored the feasibility of formulating rectal suppositories with potent antiviral drugs for on-demand use. A fixed-dose combination of tenofovir (TFV) and elvitegravir (EVG) (40 mg each) was co-formulated in six different suppository bases (three fat- and three water-soluble). Fat-soluble witepsol H15 and water-soluble polyethylene glycol (PEG) based suppositories demonstrated favorable in vitro release and were advanced to assess in vivo pharmacokinetics following rectal administration in macaques. In vivo drug release profiles were similar for both suppository bases. Median concentrations of TFV and EVG detected in rectal fluids at 2 h were 1- and 2-logs higher than the in vitro IC50, respectively; TFV-diphosphate levels in rectal tissues met or exceeded those associated with high efficacy against rectal simian HIV (SHIV) exposure in macaques. Leveraging on these findings, a PEG-based suppository with a lower dose combination of tenofovir alafenamide (TAF) and EVG (8 mg each) was developed and found to achieve similar rectal drug exposures in macaques. This study establishes the utility of rectal suppositories as a promising on-demand strategy for HIV PrEP and supports their clinical development.

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Fibrillar pharmacology of functionalized nanocellulose

Scientific Reports ◽

10.1038/s41598-020-79592-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sam Wong ◽

Simone Alidori ◽

Barbara P. Mello ◽

Bryan Aristega Almeida ◽

David Ulmert ◽

...

Keyword(s):

Aspect Ratio ◽

Fluorescent Dyes ◽

Pharmacokinetic Profile ◽

Water Soluble ◽

Size Exclusion ◽

Hydroxyl Groups ◽

Target Tissue ◽

Exclusion Chromatography ◽

Specific Accumulation

AbstractCellulose nanocrystals (CNC) are linear organic nanomaterials derived from an abundant naturally occurring biopolymer resource. Strategic modification of the primary and secondary hydroxyl groups on the CNC introduces amine and iodine group substitution, respectively. The amine groups (0.285 mmol of amine per gram of functionalized CNC (fCNC)) are further reacted with radiometal loaded-chelates or fluorescent dyes as tracers to evaluate the pharmacokinetic profile of the fCNC in vivo. In this way, these nanoscale macromolecules can be covalently functionalized and yield water-soluble and biocompatible fibrillar nanoplatforms for gene, drug and radionuclide delivery in vivo. Transmission electron microscopy of fCNC reveals a length of 162.4 ± 16.3 nm, diameter of 11.2 ± 1.52 nm and aspect ratio of 16.4 ± 1.94 per particle (mean ± SEM) and is confirmed using atomic force microscopy. Size exclusion chromatography of macromolecular fCNC describes a fibrillar molecular behavior as evidenced by retention times typical of late eluting small molecules and functionalized carbon nanotubes. In vivo, greater than 50% of intravenously injected radiolabeled fCNC is excreted in the urine within 1 h post administration and is consistent with the pharmacological profile observed for other rigid, high aspect ratio macromolecules. Tissue distribution of fCNC shows accumulation in kidneys, liver, and spleen (14.6 ± 6.0; 6.1 ± 2.6; and 7.7 ± 1.4% of the injected activity per gram of tissue, respectively) at 72 h post-administration. Confocal fluorescence microscopy reveals cell-specific accumulation in these target tissue sinks. In summary, our findings suggest that functionalized nanocellulose can be used as a potential drug delivery platform for the kidneys.

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Reductions of copper ion-mediated low-density lipoprotein (LDL) oxidations of trypsin inhibitors, the sweet potato root major proteins, and LDL binding capacities

Botanical Studies ◽

10.1186/s40529-020-00303-4 ◽

2020 ◽

Vol 61 (1) ◽

Author(s):

Yeh-Lin Lu ◽

Chia-Jung Lee ◽

Shyr-Yi Lin ◽

Wen-Chi Hou

Keyword(s):

Sweet Potato ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Trypsin Inhibitors ◽

Water Soluble ◽

Affinity Column ◽

Low Density ◽

Native Page

Abstract Background The root major proteins of sweet potato trypsin inhibitors (SPTIs) or named sporamin, estimated for 60 to 80% water-soluble proteins, exhibited many biological activities. The human low-density lipoprotein (LDL) showed to form in vivo complex with endogenous oxidized alpha-1-antitrypsin. Little is known concerning the interactions between SPTIs and LDL in vitro. Results The thiobarbituric-acid-reactive-substance (TBARS) assays were used to monitor 0.1 mM Cu2+-mediated low-density lipoprotein (LDL) oxidations during 24-h reactions with or without SPTIs additions. The protein stains in native PAGE gels were used to identify the bindings between native or reduced forms of SPTIs or soybean TIs and LDL, or oxidized LDL (oxLDL). It was found that the SPTIs additions showed to reduce LDL oxidations in the first 6-h and then gradually decreased the capacities of anti-LDL oxidations. The protein stains in native PAGE gels showed more intense LDL bands in the presence of SPTIs, and 0.5-h and 1-h reached the highest one. The SPTIs also bound to the oxLDL, and low pH condition (pH 2.0) might break the interactions revealed by HPLC. The LDL or oxLDL adsorbed onto self-prepared SPTIs-affinity column and some components were eluted by 0.2 M KCl (pH 2.0). The native or reduced SPTIs or soybean TIs showed different binding capacities toward LDL and oxLDL in vitro. Conclusion The SPTIs might be useful in developing functional foods as antioxidant and nutrient supplements, and the physiological roles of SPTIs-LDL and SPTIs-oxLDL complex in vivo will investigate further using animal models.

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Lowest aqueous picomolar fluoride ions and in vivo aluminum toxicity detection by an aluminum(iii) binding chemosensor

Dalton Transactions ◽

10.1039/d0dt03901b ◽

2021 ◽

Author(s):

Monojit Das ◽

Debdeep Maity ◽

Tusar Kanta Acharya ◽

Sudip Sau ◽

Chandan Giri ◽

...

Keyword(s):

Detection Limit ◽

Aluminum Toxicity ◽

Biological Systems ◽

Water Soluble ◽

Fluoride Ions ◽

Toxicity Effect

A water-soluble PET-based chemosensor is developed which can detect Al(iii) and F− ions up to nano- and picomolar (lowest detection so far) detection limit, respectively, also utilized to establish aluminum-toxicity effect in biological systems.

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