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katherine-medina

Peptidomimetic antibiotics disrupt the lipopolysaccharide transport bridge of drug-resi... - 0 views

  • Recently, naturally occurring peptides were proposed to interfere with the function of proteins constituting the lipopolysaccharide
  • periplasmic
    • katherine-medina
       
      The space in between the inner and outer membranes of gram-negative bacteria
  • Thanatin, a 21–amino acid defense peptide isolated from the gut of the hemipteran insect Podisus maculiventris (18), exhibits broad-spectrum antimicrobial activity
    • katherine-medina
       
      I wonder what other peptides do so as well?
  • ...7 more annotations...
  • We hypothesized that thanatin mainly acts as a competitive inhibitor of the protein-protein interactions mediating the Lpt bridge assembly
  • Thanatin, however, is not a suitable drug candidate for further development due to poor drug-like properties and rapid emergence of resistance
    • katherine-medina
       
      Why/How does thanatin have poor drug-like properties?
  • β-jellyroll
    • katherine-medina
       
      structure found in proteins
  • Here, we introduce thanatin-derived synthetic macrocyclic peptides found after a substantial medicinal chemistry effort.
    • katherine-medina
       
      Essentially they synthetically created it
  • Development of resistance against thanatin was observed after 1 day of passaging in both E. coli and K. pneumoniae and is characterized by a spontaneous FOR of 1.2 × 10−6 for E. coli at 4× MIC
    • katherine-medina
       
      That is kinda scary to think about
  • genome sequencing of a diverse panel of thanatin-resistant strains confirmed on-target modifications on LptA as the main resistance determinant in E. coli and K. pneumoniae.
  • The attractive in vitro and in vivo profile of these new antibiotics, coupled with their novel mechanism of action, showing no cross-resistance to standard of care antibiotics, may provide clinicians with additional treatment options to fight AMR, either in combination with SoC or as stand-alone antibiotics.
    • katherine-medina
       
      It is interesting to look around that these other methods that can fight off bacteria.
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    An article showing a new class of antibiotics known as a peptidomimetic antibiotic.
katherine-medina

Anti-inflammatory effects and possible mechanism of action of lupeol acetate isolated f... - 0 views

  • The latex collected from its stem bark is used for several purposes including anti-inflammatory properties and presents among its bioactive constituents the pentacyclic triterpene lupeol.
  • administered with LA,
    • katherine-medina
       
      they were trying to see if it could work as a prevenatitive treatment
  • carrageenan and dextran,
    • katherine-medina
       
      This causes inflammation
  • ...13 more annotations...
  • the effect of a very low dose of LA (0.1 mg/kg) was potentiated by the same dose of pentoxifylline (PTX), a known TNF-alpha inhibitor. L
    • katherine-medina
       
      Essentially once they put pentoxifylline into the rat the LA activated.
  • The anti-inflammatory effect of LA probably involves the opioid system, as indicated by the complete blockade of the opioid antagonist naloxone
    • katherine-medina
       
      So, the LA helped the body with inflammation due to its interaction with the opioid system.
  • rich in triterpenes
  • Carrageenan-induced mice paw edema
    • katherine-medina
       
      Cool to understand that these next two paragraphs are about how to induce inflammation
  • LA (10, 25 and 50 mg/kg, i.p.) reduced both phases of the formalin test, and the results were significant at the two higher doses. However, the effects were mainly on the 2nd phase with 61% inhibition, whereas the 1st phase was inhibited by 41% at the LA dose of 50 mg/kg, i.p. The naloxone pretreatment completely reversed the LA effect, in the 1st and 2nd phases, indicating the participation of the opioid system in LA antinociceptive and anti-inflammatory actions.
  • LA injected 30 min before carrageenan significantly decreased the carrageenan-induced neutrophil migration in a dose-dependent manner. The LA inhibitory effect against carrageenan-induced migration was about 52, 79 and 90%, at the doses of 1, 10 and 20 mg/kg, i.p., respectively
  • On the other hand, while no significant enzyme release was observed with LA at the concentrations of 1, 10 and 25 μg/mL, a small but significant LDH release (around 2 times) was detected with the higher LA concentration (50 μg/mL), probably related to the presence of 0.2% Tween 80.
  • The results show that LA at the concentrations of 50, 100 and 200 μg/mL presents no radical scavenging capacity. On the contrary, vitamin E used as the reference drug significantly decreased the absorbance value, as related to controls
    • katherine-medina
       
      LA can sadly not kill the free radicals that tend to disrupt and kill DNA and other parts of the cell.
  • In the carrageenan-treated groups pretreated with LA (50 mg/kg, i.p.) or indomethacin (10 mg/kg, i.p.), there were significant reductions of iNOS expressing cells.
  • Lupeol is found in several other species and its antinociceptive and anti-inflammatory activities have been already demonstrated [24–28]. It is accepted that the anti-inflammatory property of lupeol often accompany its immune modulatory and anti-tumor action
  • lupeol acetate presents an anti-inflammatory activity by regulating TNF-alpha and IL-2 specific mRNA, besides upregulating the synthesis of IL-10 mRNA [31].
  • In the present work, we showed that lupeol acetate (LA, 93.2% purity) isolated from the H. drasticus latex presented a potent anti-inflammatory action, in several models of inflammation in mice
  • These authors concluded that lupeol possessed an anti-inflammatory activity which is probably related to its ability to prevent the production of pro-inflammatory mediators, such as TNF-α and IL-1β.
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    This study is a good one to go back to if you are curious about alternative types of anti-inflammatory plants.
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    The carrageenan here (and the fact that you seem interested in the biochemical realm) made me think of a supplement my mom recently asked me to scope out for her (Arteriosil). It also contains a seaweed extract (rhamnan sulfate) Her doctor was recommending it for macular degeneration. Here is the product: https://shop.calroy.com/product/arterosilhp/?gclid=Cj0KCQjw7aqkBhDPARIsAKGa0oKoQchIRSlzL1_PikNwT71f1BmUVgbIM7sXUQS_lJKaGVSCT4O5R7EaAmaUEALw_wcB Here is one study from the NIH: https://pubmed.ncbi.nlm.nih.gov/32344720/
katherine-medina

IJMS | Free Full-Text | Antioxidant Versus Pro-Apoptotic Effects of Mushroom-Enriched D... - 0 views

  • In addition, the gut microbiota has also been described to be modulated by mushroom bioactive molecules, with implications in reducing liver inflammation during NAFLD progression.
  • non-alcoholic steatohepatitis (NASH)
    • katherine-medina
       
      I like the abbreviation
  • NASH is currently the third most common indication for liver transplantation in the United States and accounts for 10% of all HCC cases in Europe
  • ...22 more annotations...
  • The increase in nutrient availability causes systemic metabolic alterations that lead to an increase in hepatic mitochondrial respiration as well as changes in the mitochondrial lipid membrane composition.
  • They are also rich in phenolic acids, such as hydroxybenzoic and hydroxycinnamic acid, flavonoids, tocopherols, ascorbic acid and carotenoids that are known for their antioxidant activity
    • katherine-medina
       
      They are high in polyphenols, just like I had thought, I do wonder if they have tried to single out a certain flavonoid or stilbene in order to determine whether or not it was the mechanism that caused the positive reaction.
  • Of note, indeed NAFLD patients present a “metabolic inflexibility”, that is, a reduced capacity to switch back from
    • katherine-medina
       
      I did not know that
  • The increased levels of β-oxidation seem to result in an increase in citrate within the mitochondrial matrix that can be transported to the cytosol via the citrate-malate shuttle and converted to acetyl-CoA and oxaloacetate by the enzyme ATP-citrate lyase [90,106]. Indeed, NAFLD patients present increased citrate levels in plasma
  • An alternative explanation for the deficient mitochondrial respiration might be the alterations in the mitochondria lipid composition, which are already present in steatosis.
  • As defined by mitohormesis, ROS production is physiological at low levels, acting as a crucial effector in proliferation, expression of antioxidant enzymes and insulin signalling. However, high levels of ROS formation causes oxidative stress and cell damage by reacting with its different components [90,114,115]. Oxidative stress occurs when the antioxidant capacity of the cell is not sufficient to neutralize the overproduction of ROS. ROS generation causes the peroxidation of phospholipids and cardiolipin at the mitochondrial membrane
  • All these mechanisms seem to be involved in the progression from NAFL to NASH. Indeed, NASH patients present increased ROS production, DNA damage, as measured by 8-Oxo-2’-deoxyguanosine (8OHdG) levels, and hepatic lipid peroxidation coupled with decreased expression of ETC Com
    • katherine-medina
       
      So essentially NASH patients have a higher level of ROS which damages their DNA. increase of ROS = DNA damage
  • In parallel, the negative regulation on the inhibitor of apoptosis proteins (IAPs) mediated by the translocation of a series of IAP antagonists such as Smac, HTRA2/Omi and apoptosis-related protein in the TGF-ß signalling pathway (ARTS) to the cytosol, results in the release and activation of caspases
  • Aiming at weight loss, calorie-restricted diets and regular physical activity can improve hepatic mitochondria dysfunction by decreasing FFA liver input and alleviating oxidative stress.
  • New therapies need to be developed to target NAFLD and NASH,
    • katherine-medina
       
      Are there any new therapies to treat NASH and NAFLD
  • showed lipid metabolism-modulating properties in the liver
  • This may lead to a decrease in lipogenesis and a concomitant increase in β-oxidation that could explain the reduction in IHTG content [203]. Similarly, the supplementation with a 1% aqueous extract of A. cinnamomea for 8 weeks reduced the expression of leptin and increased the expression of adiponectin, which was accompanied by an increase of AMPK and PGC-1α and a reduced expression of ACC, FAS and SREBP
  • IHTG content that was similar to the positive control group, treated with rosiglitazone, a PPAR-agonist antidiabetic drug
    • katherine-medina
       
      Interesting, I wonder if there is more that can be done with this extract with these types of effects.
  • herefore, these studies suggest a pivotal capacity of mushroom extracts to counteract the detrimental oxidative damage of mitochondria in NAFLD.
  • which seems to exacerbate NASH. H2O2 over-production may open the mPTP, while its transmembrane diffusion to the cytoplasm may even result in highly detrimental OH• formation. [93,131,132]. In contrast, the capacity of mushroom extracts from species such as Pleurotus ostreatus (Jacq.) P. Kumm. (oyster mushroom) or G. lucidum to elevate the entire antioxidant defence system of hepatocytes, seems a more promising therapeutic effect against the oxidative stress in NASH.
  • . Such evidence further supports the potential of G. lucidum extracts in reversing mitochondrial dysfunction in NAFLD.
  • In this line of research, novel therapies aim to target apoptosis via mitochondria, using molecules that mimic BH3 proteins and disrupt the interactions of pro-apoptotic and anti-apoptotic proteins.
  • Both aqueous and ethanol extracts, or isolated compounds (GL22 from Ganoderma leucocontextum T.H Li, W.Q. Deng, Dong M. Wang & H.P. Hu) increased the pro-apoptotic Bax to anti-apoptotic Bcl-2/Bcl-xL ratio
  • The antitumorigenic effects of mushroom extracts and isolated compounds have also been demonstrated in in-vivo xenograft models, resulting in tumour size reduction and increased animal survival rates (Table 2). Furthermore, in the HCC Huh7 xenograft mice model, fatty acid binding proteins
  • Therefore, the mechanisms by which mushroom extracts or isolated compounds induce mitochondrial-related apoptosis pathways are diverse and may be related with specific bioactive compounds. Modulation of pathways crucial for cell survival and alterations in lipid homeostasis seem to be related with the pro-apoptotic effects observed in HCC cell lines and in in-vivo xenograft models.
    • katherine-medina
       
      Cool
  • To sum up, mitochondria play a central role in the pathophysiology and progression of NAFLD as well as in the development of HCC, which can be a late-stage consequence of NASH. Hepatic mitochondria undergo bioenergetic remodelling to face the metabolic burden imposed by the increased FFAs load secondary to systemic IR. In turn, a decompensation of these processes may result in ROS formation and mitochondrial dysfunction, contributing to the development of NASH. Lastly, hepatic mitochondria also seem to be involved in anti-apoptotic oncogenic processes driving HCC. Targeting mitochondrial dysfunction is thus a promising approach for the treatment of the NAFLD continuum. The following section describes some of the in-vitro and in-vivo studies on the beneficial effects of mushroom-enriched diets or mushroom-derived compounds/extracts (Box 2) in preventing/reverting such liver damage.
  • This distinct property of mushroom-based therapy or -containing diet is especially relevant in the multifactorial context of NAFLD and especially NASH, where systemic synergistic metabolic alterations need to be addressed.
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    An article detailing a bit of the effects that mushrooms can have on the liver's mitochondrial cells.
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