Nano-Oxy: Diabetic ulcer treatment using oxygen nanoparticles concept as innovation in reducing amputation rates and antibiotics usage

Diabetes mellitus is a metabolic disease characterized by chronic hyperglycemia caused by defects in insulin secretion, insulin reactions, or both. More than one third of diabetic patients have complications in the form of diabetic ulcers, and half are infected, and 15% of these infections require limb amputation. High cost expenditure and risks of microbial resistance to antibiotics also adds the complexity of the problem. The purpose of this literature review is to offer Nano-Oxy, using oxygen in nanoparticle size, as an alternative diabetic ulcer treatment. Literature searching was conducted through online search method. Oxygen therapy has been widely used to treat diabetic ulcers, including hyperbaric oxygen therapy (HOT) and topical oxygen therapy (TOT). Both of them have good results on diabetic ulcer therapy. Oxygen can act as an antimicrobial agent through the activation mechanism of neutrophils and macrophages which play a role in phagocytosis process and ROS regeneration. Nano-Oxy has advantages than the previous therapy, such as it does not cause barotrauma, oxygen poisoning, and low risk of burning. The mechanism of how Nano-Oxy works is similar with the Micro-nanobubbles (MNBs) concept. The negatively charged surface of MNBs can prevent them from aggregating, attracts particles, and help remove debris. MNBs also generate free radicals while shrinking in water, which contribute to its antibacterial effect. In addition, Nano-oxygen technology can be applied externally, but still have effect on the intended target cells. Therefore, Nano-oxygen can be used as a diabetic ulcer therapy to replace the role of antibiotics.

Structural Insights into Sphingosine-1-phosphate Receptor Activation

As a critical sphingolipid metabolite, sphingosine-1-phosphate (S1P) plays an essential role in immune and vascular systems. There are five S1P receptors, designated as S1PR1-5, encoded in the human genome, and their activities are governed by endogenous S1P, lipid-like S1P mimics, or non-lipid-like therapeutic molecules. Among S1PRs, S1PR1 stands out due to its non-redundant functions, such as the egress of T and B cells from the thymus and secondary lymphoid tissues, making it a potential therapeutic target. However, the structural basis of S1PR1 activation and regulation by various agonists remains unclear. Here we reported four atomic resolution cryo-EM structures of Gi-coupled human S1PR1 complexes: bound to endogenous agonist d18:1 S1P, benchmark lipid-like S1P mimic phosphorylated Fingolimod ((S)-FTY720-P), or non-lipid-like therapeutic molecule CBP-307 in two binding modes. Our results revealed the similarities and differences of activation of S1PR1 through distinct ligands binding to the amphiphilic orthosteric pocket. We also proposed a two-step "shallow to deep" transition process of CBP-307 for S1PR1 activation. Both binding modes of CBP-307 could activate S1PR1, but from shallow to deep transition may trigger the rotation of the N-terminal helix of Gαi and further stabilize the complex by increasing the Gαi interaction with the cell membrane. We combine with extensive biochemical analysis and molecular dynamic simulations to suggest key steps of S1P binding and receptor activation. The above results decipher the common feature of the S1PR1 agonist recognition and activation mechanism and will firmly promote the development of therapeutics targeting S1P receptors.

The Role of Oxidative Stress in Intervertebral Disc Degeneration

Intervertebral disc degeneration is a very common type of degenerative disease causing severe socioeconomic impact, as well as a major cause of discogenic low back pain and herniated discs, placing a heavy burden on patients and the clinicians who treat them. IDD is known to be associating with a complex process involving in extracellular matrix and cellular damage, and in recent years, there is increasing evidence that oxidative stress is an important activation mechanism of IDD and that reactive oxygen and reactive nitrogen species regulate matrix metabolism, proinflammatory phenotype, autophagy and senescence in intervertebral disc cells, apoptosis, autophagy, and senescence. Despite the tremendous efforts of researchers within the field of IDD pathogenesis, the proven strategies to prevent and treat this disease are still very limited. Up to now, several antioxidants have been proved to be effective for alleviating IDD. In this article, we discussed that oxidative stress accelerates disc degeneration by influencing aging, inflammation, autophagy, and DNA methylation, and summarize some antioxidant therapeutic measures for IDD, indicating that antioxidant therapy for disc degeneration holds excellent promise.

Identification of a phage display-derived peptide interacting with the N-terminal region of Factor VII activating protease (FSAP) enables characterization of zymogen activation.

Increased Factor VII activating protease (FSAP) activity has a protective effect in diverse disease conditions as inferred from studies in FSAP-/- mice and humans deficient in FSAP activity due to a single nucleotide polymorphism. The activation of FSAP zymogen in plasma is mediated by extracellular histones that are released during tissue injury or inflammation or by positively charged surfaces. However, it is not clear if this activation mechanism is specific and amenable to manipulation. Using a phage display approach we have identified a peptide, NNKC9/41, that activates pro-FSAP in plasma. Other commonly found zymogens in the plasma were not activated. Binding studies with FSAP domain deletion mutants indicate that the N-terminus of FSAP is the key interaction site of this peptide. Blocking the contact pathway of coagulation did not influence pro-FSAP activation by the peptide. In a monoclonal antibody screen, we identified MA-FSAP-38C7 that prevented the activation of pro-FSAP by the peptide. This antibody bound to the LESLDP sequence (amino acids 30-35) in the N-terminus of FSAP. The plasma clotting time was shortened by NNKC9/41 and this was reversed by MA-FSAP-38C7 demonstrating the utility of this peptide. Identification of this peptide, and the corresponding interaction site, provides proof of principle that it is possible to activate a single protease zymogen in blood in a specific manner. Peptide NNKC/41 will be useful as a tool to delineate the molecular mechanism of activation of pro-FSAP in more detail, elucidate its biological role.

Fluorescence activation mechanism and imaging of drug permeation with new sensors for smoking-cessation ligands

Nicotinic partial agonists provide an accepted aid for smoking cessation and thus contribute to decreasing tobacco-related disease. Improved drugs constitute a continued area of study. However, there remains no reductionist method to examine the cellular and subcellular pharmacokinetic properties of these compounds in living cells. Here, we developed new intensity-based drug sensing fluorescent reporters ('iDrugSnFRs') for the nicotinic partial agonists dianicline, cytisine, and two cytisine derivatives - 10-fluorocytisine and 9-bromo-10-ethylcytisine. We report the first atomic-scale structures of liganded periplasmic binding protein-based biosensors, accelerating development of iDrugSnFRs and also explaining the activation mechanism. The nicotinic iDrugSnFRs detect their drug partners in solution, as well as at the plasma membrane (PM) and in the endoplasmic reticulum (ER) of cell lines and mouse hippocampal neurons. At the PM, the speed of solution changes limits the growth and decay rates of the fluorescence response in almost all cases. In contrast, we found that rates of membrane crossing differ among these nicotinic drugs by > 30 fold. The new nicotinic iDrugSnFRs provide insight into the real-time pharmacokinetic properties of nicotinic agonists and provide a methodology whereby iDrugSnFRs can inform both pharmaceutical neuroscience and addiction neuroscience.

Analysis of Pathogenic Bacteria of Mooren’s Ulcer and T Lymphocyte Activation

To analyze the distribution and types of pathogenic bacteria of Mooren’s ulcer and the activation mechanism of T lymphocytes to provide reference for the treatment of Mooren’s ulcer, 156 patients (162 eyes) who were in the hospital were rolled into the observation group. During the same period, 134 healthy people were rolled into the control group. The distribution of infectious pathogens in the observation group was identified. Then, flow cytometry was adopted to separate and detect the peripheral blood lymphocytes of patients, and RT-PCR was used to detect levels of the transcription factor T-bet, GATA-3, and Stat5 in peripheral blood mononuclear cells (PBMCs). It was found that fungal pathogens accounted for 43.59%; the bacterial infection rate was 40.38%. In the observation group, the CD4, CD8, and C25 were expressed more (P < 0.01), and the CD45 and CD45R were expressed less than the control group (P < 0.05); the proportion of Th1 cells was obviously higher (P < 0.01); the expression of T-bet and GATA-3 was obviously higher (P < 0.05), the percentage of HLA-DR in CD4+ and HLA-DR, CD-25, and CD69 in CD8+ positive cells was obviously higher (P < 0.05). In conclusion, fungal infection rate of Mooren’s ulcer is relatively high, peripheral blood T cells and their subgroups are abnormally activated, and T cell activation is related to the pathogenesis of Mooren’s ulcer.