Autophagy Deficiency by Atg4B Loss Leads to Metabolomic Alterations in Mice

Autophagy is an essential protective mechanism that allows mammalian cells to cope with a variety of stressors and contributes to maintaining cellular and tissue homeostasis. Due to these crucial roles and also to the fact that autophagy malfunction has been described in a wide range of pathologies, an increasing number of in vivo studies involving animal models targeting autophagy genes have been developed. In mammals, total autophagy inactivation is lethal, and constitutive knockout models lacking effectors of this route are not viable, which has hindered so far the analysis of the consequences of a systemic autophagy decline. Here, we take advantage of atg4b−/− mice, an autophagy-deficient model with only partial disruption of the process, to assess the effects of systemic reduction of autophagy on the metabolome. We describe for the first time the metabolic footprint of systemic autophagy decline, showing that impaired autophagy results in highly tissue-dependent alterations that are more accentuated in the skeletal muscle and plasma. These changes, which include changes in the levels of amino-acids, lipids, or nucleosides, sometimes resemble those that are frequently described in conditions like aging, obesity, or cardiac damage. We also discuss different hypotheses on how impaired autophagy may affect the metabolism of several tissues in mammals.

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Designing P. aeruginosa synthetic phages with reduced genomes

Scientific Reports ◽

10.1038/s41598-021-81580-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Diana P. Pires ◽

Rodrigo Monteiro ◽

Dalila Mil-Homens ◽

Arsénio Fialho ◽

Timothy K. Lu ◽

...

Keyword(s):

Galleria Mellonella ◽

Antibacterial Properties ◽

Genetically Engineered ◽

In Vivo Studies ◽

Infection Model ◽

Promising Therapeutic Approach ◽

Genes Encoding ◽

First Time

AbstractIn the era where antibiotic resistance is considered one of the major worldwide concerns, bacteriophages have emerged as a promising therapeutic approach to deal with this problem. Genetically engineered bacteriophages can enable enhanced anti-bacterial functionalities, but require cloning additional genes into the phage genomes, which might be challenging due to the DNA encapsulation capacity of a phage. To tackle this issue, we designed and assembled for the first time synthetic phages with smaller genomes by knocking out up to 48% of the genes encoding hypothetical proteins from the genome of the newly isolated Pseudomonas aeruginosa phage vB_PaeP_PE3. The antibacterial efficacy of the wild-type and the synthetic phages was assessed in vitro as well as in vivo using a Galleria mellonella infection model. Overall, both in vitro and in vivo studies revealed that the knock-outs made in phage genome do not impair the antibacterial properties of the synthetic phages, indicating that this could be a good strategy to clear space from phage genomes in order to enable the introduction of other genes of interest that can potentiate the future treatment of P. aeruginosa infections.

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Phytochemistry and Pharmacology of the Genus Pedicularis Used in Traditional Chinese Medicine

The American Journal of Chinese Medicine ◽

10.1142/s0192415x14500670 ◽

2014 ◽

Vol 42 (05) ◽

pp. 1071-1098 ◽

Cited By ~ 13

Author(s):

Mao-Xing Li ◽

Xi-Rui He ◽

Rui Tao ◽

Xinyuan Cao

Keyword(s):

Chinese Medicine ◽

Traditional Chinese Medicine ◽

Chemical Constituents ◽

Iridoid Glycosides ◽

In Vivo Studies ◽

Chemical Components ◽

Wide Range ◽

Phenylpropanoid Glycosides

In the present review, the literature data on the chemical constituents and biological investigations of the genus Pedicularis are summarized. Some species of Pedicularis have been widely applied in traditional Chinese medicine. A wide range of chemical components including iridoid glycosides, phenylpropanoid glycosides (PhGs), lignans glycosides, flavonoids, alkaloids and other compounds have been isolated and identified from the genus Pedicularis. In vitro and in vivo studies indicated some monomer compounds and extracts from the genus Pedicularis have been found to possess antitumor, hepatoprotective, anti-oxidative, antihaemolysis, antibacterial activity, fatigue relief of skeletal muscle, nootropic effect and other activities.

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Enhanced xenobiotic transporter expression in normal teleost hepatocytes: response to environmental and chemotherapeutic toxins

Journal of Experimental Biology ◽

10.1242/jeb.204.2.217 ◽

2001 ◽

Vol 204 (2) ◽

pp. 217-227

Author(s):

J.A. Albertus ◽

R.O. Laine

Keyword(s):

Mammalian Cells ◽

Cellular Localization ◽

Fundulus Heteroclitus ◽

Environmental Pollutants ◽

Human Tumor ◽

Aquatic Organisms ◽

In Vivo Studies ◽

Multixenobiotic Resistance

Many aquatic organisms are resistant to environmental pollutants, probably because their inherent multi-drug-resistant protein extrusion pump (pgp) can be co-opted to handle man-made pollutants. This mechanism of multixenobiotic resistance is similar to the mechanism of multidrug resistance exhibited in chemotherapy-resistant human tumor cells. In the present study, a variety of techniques were used to characterize this toxin defense system in killifish (Fundulus heteroclitus) hepatocytes. The cellular localization and activity of the putative drug efflux system were evaluated. In addition, in vitro and in vivo studies were used to examine the range of expression of this putative drug transporter in the presence of environmental and chemotherapeutic toxins. The broad range of pgp expression generally observed in transformed mammalian cells was found in normal cells of our teleost model. Our findings suggest that the expression of the pgp gene in the killifish could be an excellent indicator of toxin levels or stressors in the environment.

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Inhibiting myosin-ATPase reveals a dynamic range of mitochondrial respiratory control in skeletal muscle

Biochemical Journal ◽

10.1042/bj20110366 ◽

2011 ◽

Vol 437 (2) ◽

pp. 215-222 ◽

Cited By ~ 93

Author(s):

Christopher G. R. Perry ◽

Daniel A. Kane ◽

Chien-Te Lin ◽

Rachel Kozy ◽

Brook L. Cathey ◽

...

Keyword(s):

Skeletal Muscle ◽

Dynamic Range ◽

Energy Charge ◽

Respiratory Control ◽

Basic Research ◽

Dependent Manner ◽

Atpase Inhibitor ◽

Wide Range ◽

The Impact

Assessment of mitochondrial ADP-stimulated respiratory kinetics in PmFBs (permeabilized fibre bundles) is increasingly used in clinical diagnostic and basic research settings. However, estimates of the Km for ADP vary considerably (~20–300 μM) and tend to overestimate respiration at rest. Noting that PmFBs spontaneously contract during respiration experiments, we systematically determined the impact of contraction, temperature and oxygenation on ADP-stimulated respiratory kinetics. BLEB (blebbistatin), a myosin II ATPase inhibitor, blocked contraction under all conditions and yielded high Km values for ADP of >~250 and ~80 μM in red and white rat PmFBs respectively. In the absence of BLEB, PmFBs contracted and the Km for ADP decreased ~2–10-fold in a temperature-dependent manner. PmFBs were sensitive to hyperoxia (increased Km) in the absence of BLEB (contracted) at 30 °C but not 37 °C. In PmFBs from humans, contraction elicited high sensitivity to ADP (Km<100 μM), whereas blocking contraction (+BLEB) and including a phosphocreatine/creatine ratio of 2:1 to mimic the resting energetic state yielded a Km for ADP of ~1560 μM, consistent with estimates of in vivo resting respiratory rates of <1% maximum. These results demonstrate that the sensitivity of muscle to ADP varies over a wide range in relation to contractile state and cellular energy charge, providing evidence that enzymatic coupling of energy transfer within skeletal muscle becomes more efficient in the working state.

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Development of an LDL Receptor-Targeted Peptide Susceptible to Facilitate the Brain Access of Diagnostic or Therapeutic Agents

Biology ◽

10.3390/biology9070161 ◽

2020 ◽

Vol 9 (7) ◽

pp. 161

Author(s):

Séverine André ◽

Lionel Larbanoix ◽

Sébastien Verteneuil ◽

Dimitri Stanicki ◽

Denis Nonclercq ◽

...

Keyword(s):

Ldl Receptor ◽

Density Lipoprotein ◽

Therapeutic Agents ◽

In Vivo Studies ◽

Phage Display Technology ◽

Brain Penetration ◽

Wide Range ◽

The Brain

Blood-brain barrier (BBB) crossing and brain penetration are really challenging for the delivery of therapeutic agents and imaging probes. The development of new crossing strategies is needed, and a wide range of approaches (invasive or not) have been proposed so far. The receptor-mediated transcytosis is an attractive mechanism, allowing the non-invasive penetration of the BBB. Among available targets, the low-density lipoprotein (LDL) receptor (LDLR) shows favorable characteristics mainly because of the lysosome-bypassed pathway of LDL delivery to the brain, allowing an intact discharge of the carried ligand to the brain targets. The phage display technology was employed to identify a dodecapeptide targeted to the extracellular domain of LDLR (ED-LDLR). This peptide was able to bind the ED-LDLR in the presence of natural ligands and dissociated at acidic pH and in the absence of calcium, in a similar manner as the LDL. In vitro, our peptide was endocytosed by endothelial cells through the caveolae-dependent pathway, proper to the LDLR route in BBB, suggesting the prevention of its lysosomal degradation. The in vivo studies performed by magnetic resonance imaging and fluorescent lifetime imaging suggested the brain penetration of this ED-LDLR-targeted peptide.

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Erythrocytes as Carriers: From Drug Delivery to Biosensors

Pharmaceutics ◽

10.3390/pharmaceutics12030276 ◽

2020 ◽

Vol 12 (3) ◽

pp. 276 ◽

Cited By ~ 7

Author(s):

Larisa Koleva ◽

Elizaveta Bovt ◽

Fazoil Ataullakhanov ◽

Elena Sinauridze

Keyword(s):

Drug Delivery ◽

Targeted Drug Delivery ◽

Reticuloendothelial System ◽

In Vivo Studies ◽

Bioactive Substances ◽

Target Organs ◽

Wide Range ◽

Opening Up ◽

Gradual Release

Drug delivery using natural biological carriers, especially erythrocytes, is a rapidly developing field. Such erythrocytes can act as carriers that prolong the drug’s action due to its gradual release from the carrier; as bioreactors with encapsulated enzymes performing the necessary reactions, while remaining inaccessible to the immune system and plasma proteases; or as a tool for targeted drug delivery to target organs, primarily to cells of the reticuloendothelial system, liver and spleen. To date, erythrocytes have been studied as carriers for a wide range of drugs, such as enzymes, antibiotics, anti-inflammatory, antiviral drugs, etc., and for diagnostic purposes (e.g., magnetic resonance imaging). The review focuses only on drugs loaded inside erythrocytes, defines the main lines of research for erythrocytes with bioactive substances, as well as the advantages and limitations of their application. Particular attention is paid to in vivo studies, opening-up the potential for the clinical use of drugs encapsulated into erythrocytes.

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In Vivo Responses of Single Olfactory Receptor Neurons of Channel Catfish to Binary Mixtures of Amino Acids

Journal of Neurophysiology ◽

10.1152/jn.1997.77.1.1 ◽

1997 ◽

Vol 77 (1) ◽

pp. 1-8 ◽

Cited By ~ 27

Author(s):

Jiesheng Kang ◽

John Caprio

Keyword(s):

Amino Acids ◽

Binary Mixtures ◽

Ictalurus Punctatus ◽

Channel Catfish ◽

Olfactory Receptor ◽

Olfactory Receptor Neurons ◽

Electrophysiological Response ◽

Receptor Neurons ◽

First Time

Kang, Jiesheng and John Caprio. In vivo response of single olfactory receptor neurons of channel catfish to binary mixtures of amino acids. J. Neurophysiol. 77: 1–8, 1997. For the first time in any vertebrate, in vivo responses of single olfactory receptor neurons to odorant mixtures were studied quantitatively. Extracellular electrophysiological response of 54 single olfactory receptor neurons from 23 channel catfish, Ictalurus punctatus, to binary mixtures of amino acids and to their components were recorded simultaneously with the electroolfactogram (EOG). For 57% (73 of 128) of the tests, no significant change (N) from spontaneous activity occurred. Responses to the remaining 55 tests of binary mixtures were excitatory (E; 13%) or suppressive (S; 30%). No response type was associated with any specific mixture across the neurons sampled. Eighty-six percent of the responses of catfish olfactory receptor neurons to binary mixtures were classifed similar to at least one of the component responses, a percentage comparable (i.e., 89%) with that observed for single olfactory bulb neurons in the same species to equivalent binary mixtures. The responses of single olfactory receptor neurons to component-similar binary mixtures (i.e., component responses were both E, both S, and both N, respectively) were generally (80% of 59 tests) classified similar to the responses to the components. For E+N and S+N binary mixtures, the N component often (66% of 58 tests) reduced or concealed (i.e., “masked”) the excitatory and suppressive responses, respectively. For the majority (6 of 11 tests) of E+S binary mixtures, null activity resulted. Responses to the remaining five tests were either excitatory ( n = 3) or suppressive ( n = 2).

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Myofibrillar Protein Abundance and Anabolic Signaling in Myotubes Depleted of E1 Alpha Subunit of Branched-Chain Ketoacid Dehydrogenase Complex

Current Developments in Nutrition ◽

10.1093/cdn/nzaa049_035 ◽

2020 ◽

Vol 4 (Supplement_2) ◽

pp. 642-642

Author(s):

Glory Madu ◽

Olasunkanmi Adegoke

Keyword(s):

Skeletal Muscle ◽

Amino Acids ◽

Protein Content ◽

Muscle Protein ◽

Essential Amino Acids ◽

Myofibrillar Protein ◽

L6 Myotubes ◽

Branched Chain ◽

Ketoacid Dehydrogenase

Abstract Objectives Branched-chain amino acids (BCAAs) are essential amino acids that are crucial for skeletal muscle anabolism. Thus, alterations in their levels are associated with muscle atrophic diseases such as cancer, chronic inflammatory and neurological disorders. Others have linked impairments in BCAA metabolism to the development of insulin resistance and its sequelae. Compared to the effects of theses amino acids, much less is known on how impairment in BCAA catabolism affects skeletal muscle. BCAA catabolism starts with the reversible transamination by the mitochondrial enzyme branched-chain aminotransferase 2 (BCAT2). This is followed by the irreversible carboxylation, catalyzed by branched-chain ketoacid dehydrogenase (BCKD) complex. We have shown that BCAT2 and BCKD are essential for the differentiation of skeletal myoblasts into myotubes. Here, we investigated the effect of depletion of BCAT2 or of E1a subunit of BCKD in differentiated myotubes. Methods On day 4 of differentiation, L6 myotubes were transfected with the following siRNA oligonucleotides: scrambled (control), BCAT2, or E1a subunit of BCKD. Results Forty-eight hours after transfection, compared to control or BCAT2 siRNA group, we observed improved myotube structure in BCKD-depleted cells. BCKD depletion augmented myofibrillar protein levels: myosin heavy chain (MHC, 2-fold) and tropomyosin (4-fold), P < 0.05, n = 3. To further analyze the increase in myofibrillar protein content, we examined signaling through mTORC1 (mechanistic target of rapamycin complex 1), a vital complex necessary for skeletal muscle anabolism. BCKD depletion increased the phosphorylation of mTORC1 upstream activator AKT (52%, P < 0.05, n = 3), and of mTORC1 downstream substrates by 25%-86%, consistent with the increase in myofibrillar proteins. Finally, in myotubes treated with the catabolic cytokine (tumor necrosis factor-a), BCKD depletion tended to increase the abundance of tropomyosin (a myofibrillar protein). Conclusions We showed that depletion of BCKD enhanced myofibrillar protein content and anabolic signaling. If these data are confirmed in vivo, development of dietary and other interventions that target BCKD abundance or functions may promote muscle protein anabolism in individuals with muscle wasting conditions. Funding Sources MHRC, NSERC York U.

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Nutraceutical Activity in Osteoarthritis Biology: A Focus on the Nutrigenomic Role

Cells ◽

10.3390/cells9051232 ◽

2020 ◽

Vol 9 (5) ◽

pp. 1232

Author(s):

Stefania D’Adamo ◽

Silvia Cetrullo ◽

Veronica Panichi ◽

Erminia Mariani ◽

Flavio Flamigni ◽

...

Keyword(s):

Signaling Pathways ◽

Antioxidant Activities ◽

Synergistic Effects ◽

National Health System ◽

Bioactive Molecules ◽

Joint Disease ◽

In Vivo Studies ◽

Wide Range

Osteoarthritis (OA) is a disease associated to age or conditions that precipitate aging of articular cartilage, a post-mitotic tissue that remains functional until the failure of major homeostatic mechanisms. OA severely impacts the national health system costs and patients’ quality of life because of pain and disability. It is a whole-joint disease sustained by inflammatory and oxidative signaling pathways and marked epigenetic changes responsible for catabolism of the cartilage extracellular matrix. OA usually progresses until its severity requires joint arthroplasty. To delay this progression and to improve symptoms, a wide range of naturally derived compounds have been proposed and are summarized in this review. Preclinical in vitro and in vivo studies have provided proof of principle that many of these nutraceuticals are able to exert pleiotropic and synergistic effects and effectively counteract OA pathogenesis by exerting both anti-inflammatory and antioxidant activities and by tuning major OA-related signaling pathways. The latter are the basis for the nutrigenomic role played by some of these compounds, given the marked changes in the transcriptome, miRNome, and methylome. Ongoing and future clinical trials will hopefully confirm the disease-modifying ability of these bioactive molecules in OA patients.

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Pleiotropic Biological Effects of Dietary Phenolic Compounds and their Metabolites on Energy Metabolism, Inflammation and Aging

Molecules ◽

10.3390/molecules25030596 ◽

2020 ◽

Vol 25 (3) ◽

pp. 596 ◽

Cited By ~ 3

Author(s):

María del Carmen Villegas-Aguilar ◽

Álvaro Fernández-Ochoa ◽

María de la Luz Cádiz-Gurrea ◽

Sandra Pimentel-Moral ◽

Jesús Lozano-Sánchez ◽

...

Keyword(s):

Energy Metabolism ◽

Phenolic Compounds ◽

Molecular Mechanisms ◽

Biological Effects ◽

Biological Properties ◽

In Vivo Studies ◽

Wide Range ◽

High Prevalence

Dietary phenolic compounds are considered as bioactive compounds that have effects in different chronic disorders related to oxidative stress, inflammation process, or aging. These compounds, coming from a wide range of natural sources, have shown a pleiotropic behavior on key proteins that act as regulators. In this sense, this review aims to compile information on the effect exerted by the phenolic compounds and their metabolites on the main metabolic pathways involved in energy metabolism, inflammatory response, aging and their relationship with the biological properties reported in high prevalence chronic diseases. Numerous in vitro and in vivo studies have demonstrated their pleiotropic molecular mechanisms of action and these findings raise the possibility that phenolic compounds have a wide variety of roles in different targets.

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