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Science Immunology Jun 2024Intestinal inflammation shifts microbiota composition and metabolism. How the host monitors and responds to such changes remains unclear. Here, we describe a protective...
Intestinal inflammation shifts microbiota composition and metabolism. How the host monitors and responds to such changes remains unclear. Here, we describe a protective mechanism by which mucosal-associated invariant T (MAIT) cells detect microbiota metabolites produced upon intestinal inflammation and promote tissue repair. At steady state, MAIT ligands derived from the riboflavin biosynthesis pathway were produced by aerotolerant bacteria residing in the colonic mucosa. Experimental colitis triggered luminal expansion of riboflavin-producing bacteria, leading to increased production of MAIT ligands. Modulation of intestinal oxygen levels suggested a role for oxygen in inducing MAIT ligand production. MAIT ligands produced in the colon rapidly crossed the intestinal barrier and activated MAIT cells, which expressed tissue-repair genes and produced barrier-promoting mediators during colitis. Mice lacking MAIT cells were more susceptible to colitis and colitis-driven colorectal cancer. Thus, MAIT cells are sensitive to a bacterial metabolic pathway indicative of intestinal inflammation.
Topics: Animals; Mucosal-Associated Invariant T Cells; Colitis; Dysbiosis; Mice; Gastrointestinal Microbiome; Mice, Inbred C57BL; Mice, Knockout; Intestinal Mucosa; Riboflavin
PubMed: 38905325
DOI: 10.1126/sciimmunol.adi8954 -
Photochemistry and Photobiology Jun 2024Exposure to phototoxicants and photosensitizers can result in the generation of reactive oxygen species (ROS), leading to oxidative stress, DNA damage, and various...
Exposure to phototoxicants and photosensitizers can result in the generation of reactive oxygen species (ROS), leading to oxidative stress, DNA damage, and various skin-related issues such as aging, allergies, and cancer. While several photo-protectants offer defense against ultraviolet radiation (UV-R), their effectiveness is often limited by photo-instability. Sunset Yellow (SY), an FDA-approved food dye, possesses significant UV-R and visible light absorption properties. However, its photoprotective potential has remained unexplored. Our investigation reveals that SY exhibits remarkable photostability for up to 8 h under both UV-R and sunlight. Notably, SY demonstrates the ability to quench ROS, including singlet oxygen (O), superoxide radicals ( ), and hydroxyl radicals (·OH) induced by rose bengal, riboflavin and levofloxacin, respectively. Moreover, SY proves effective in protecting against the apoptotic and necrotic cell death induced by the phototoxicant chlorpromazine (CPZ) in HaCaT cells. Further, it was observed that SY imparts photoprotection by inhibiting intracellular ROS generation and calcium release. Genotoxicity evaluation provides additional evidence supporting SY's photoprotective effects against CPZ-induced DNA damage. In conclusion, these findings underscore the potential of SY as a promising photoprotective agent against the toxic hazards induced by phototoxicants, suggesting its prospective application in the formulation of broad-spectrum sunscreens.
PubMed: 38899585
DOI: 10.1111/php.13966 -
Computers in Biology and Medicine May 2024Keratoconus (KC) is a degenerative condition affecting the cornea, characterized by progressive thinning and bulging, which can ultimately result in serious visual...
Keratoconus (KC) is a degenerative condition affecting the cornea, characterized by progressive thinning and bulging, which can ultimately result in serious visual impairment. The onset and progression of KC are closely tied to the gradual weakening of the cornea's biomechanical properties. KC progression can be prevented with corneal cross-linking (CXL), but this treatment has shortcomings, and evaluating its tissue stiffening effect is important for determining its efficacy. In this field, the shortage of human corneas has made it necessary for most previous studies to rely on animal corneas, which have different microstructure and may be affected differently from human corneas. In this research, we have used the lenticules obtained through small incision lenticule extraction (SMILE) surgeries as a source of human tissue to assess CXL. And to further improve the results' reliability, we used inflation testing, personalized finite element modeling, numerical optimization and histology microstructure analysis. These methods enabled determining the biomechanical and histological effects of CXL protocols involving different irradiation intensities of 3, 9, 18, and 30 mW/cm, all delivering the same total energy dose of 5.4 J/cm. The results showed that the CXL effect did not vary significantly with protocols using 3-18 mW/cm irradiance, but there was a significant efficacy drop with 30 mW/cm irradiance. This study validated the updated algorithm and provided guidance for corneal lenticule reuse and the effects of different CXL protocols on the biomechanical properties of the human corneal stroma.
PubMed: 38897147
DOI: 10.1016/j.compbiomed.2024.108607 -
Journal of Clinical Medicine May 2024Progressive auditory dysfunction is common in patients with generalized neurodegenerative conditions, but clinicians currently lack the diagnostic tools to determine the...
BACKGROUND
Progressive auditory dysfunction is common in patients with generalized neurodegenerative conditions, but clinicians currently lack the diagnostic tools to determine the location/degree of the pathology and, hence, to provide appropriate intervention. In this study, we present the white-matter microstructure measurements derived from a novel diffusion-weighted magnetic resonance imaging (dMRI) technique in a patient with axonal auditory neuropathy and consider the findings in relation to the auditory intervention outcomes.
METHODS
We tracked the hearing changes in an adolescent with Riboflavin Transporter Deficiency (Type 2), evaluating the sound detection/discrimination, auditory evoked potentials, and both structural- and diffusion-weighted MRI findings over a 3-year period. In addition, we explored the effect of bilateral cochlear implantation in this individual.
RESULTS
Between the ages of 15 years and 18 years, the patient showed a complete loss of functional hearing ability. The auditory brainstem response testing indicated an auditory neuropathy with evidence of normal cochlear function but disrupted auditory neural activity. While three structural MRI assessments across this period showed a clinically normal cochleovestibular anatomy, the dMRI evaluation revealed a significant loss of fiber density consistent with axonopathy. The subsequent cochlear implant function was affected with the high levels of current required to elicit auditory sensations and concomitant vestibular and facial nerve stimulation issues.
CONCLUSIONS
The case study demonstrates the ability of dMRI technologies to identify the subtle white-matter microstructure changes in the auditory pathway, which may disrupt the neural function in patients with auditory axonopathy.
PubMed: 38892782
DOI: 10.3390/jcm13113072 -
Nutrients Jun 2024Beef is an important source of high-quality protein and several micronutrients, including iron, zinc, and B vitamins. We determined beef intake and its relationship with...
Beef Consumption Is Associated with Higher Intakes and Adequacy of Key Nutrients in Older Adults Age 60+ Years: National Health and Nutrition Examination Survey 2011-2018 Analysis.
Beef is an important source of high-quality protein and several micronutrients, including iron, zinc, and B vitamins. We determined beef intake and its relationship with intakes of nutrients and their adequacy using 24 h dietary recall data from 5868 older adults. Usual intakes from foods were determined using the National Cancer Institute method, and the percent of the population below the estimated average requirement or above adequate intake was estimated. A high percentage of older adults did not meet nutrient recommendations for vitamin D (96%), choline (96%), vitamin E (84%), potassium (70%), calcium (63%), magnesium (60%), vitamin C (46%), vitamin A (39%), zinc (21%), vitamin B (19%), and folate (15%). About 68% of older adults were beef consumers with a mean intake of 56 g/day. Beef consumers had higher ( < 0.05) intakes of energy, protein, calcium, iron, phosphorus, selenium, sodium, zinc, thiamin, riboflavin, niacin, vitamin B, and choline, and a higher ( < 0.05) proportion met nutrient recommendations for protein, calcium, copper, zinc, thiamin, folate, and vitamin B than non-consumers. Consumers of fresh, ground, and processed beef also had generally higher intakes and lower inadequacies of many nutrients depending on the beef type. In conclusion, older adults generally had poor nutrient adequacy from their diets, while beef consumers had higher nutrient intakes and adequacy for certain key nutrients, which are inherently generally available from beef or from foods consumed with beef.
Topics: Humans; Aged; Male; Female; Middle Aged; Nutrition Surveys; Red Meat; Diet; Nutrients; Nutritional Status; Micronutrients; United States; Aged, 80 and over; Recommended Dietary Allowances; Nutritive Value; Cattle; Animals; Nutritional Requirements
PubMed: 38892711
DOI: 10.3390/nu16111779 -
Graefe's Archive For Clinical and... Jun 2024To evaluate progression of keratoconus in patients where CXL treatment was interrupted due to insufficient swelling of the cornea.
PURPOSE
To evaluate progression of keratoconus in patients where CXL treatment was interrupted due to insufficient swelling of the cornea.
METHODS
A retrospective review was conducted of all patients with keratoconus diagnosis who underwent CXL at the Department of Ophthalmology, Örebro University Hospital (USÖ) during the years 2010-2017. In total 377 eyes of 280 patients were screened for inclusion. In 17 eyes (15 patients), the treatment was interrupted due to insufficient swelling of the cornea. Patient journals were reviewed and keratometry examinations were analysed for long-term progression.
RESULTS
Eleven eyes (nine patients) were included in the study. Five eyes showed no signs of progression after the interrupted CXL treatment. In one eye progression continued, however, first after a period of a number of years, indicating a delayed course of clinical progression.
CONCLUSION
This study indicates that debridement of the corneal epithelium and riboflavin administration without intense UVA radiation may slow or arrest the progression of keratoconus, likely due to photosensitisation from ambient light.
PubMed: 38888803
DOI: 10.1007/s00417-024-06505-x -
Nature Communications Jun 2024Methylenetetrahydrofolate reductase (MTHFR) is a pivotal flavoprotein connecting the folate and methionine methyl cycles, catalyzing the conversion of...
Methylenetetrahydrofolate reductase (MTHFR) is a pivotal flavoprotein connecting the folate and methionine methyl cycles, catalyzing the conversion of methylenetetrahydrofolate to methyltetrahydrofolate. Human MTHFR (hMTHFR) undergoes elaborate allosteric regulation involving protein phosphorylation and S-adenosylmethionine (AdoMet)-dependent inhibition, though other factors such as subunit orientation and FAD status remain understudied due to the lack of a functional structural model. Here, we report crystal structures of Chaetomium thermophilum MTHFR (cMTHFR) in both active (R) and inhibited (T) states. We reveal FAD occlusion by Tyr361 in the T-state, which prevents substrate interaction. Remarkably, the inhibited form of cMTHFR accommodates two AdoMet molecules per subunit. In addition, we conducted a detailed investigation of the phosphorylation sites in hMTHFR, three of which were previously unidentified. Based on the structural framework provided by our cMTHFR model, we propose a possible mechanism to explain the allosteric structural transition of MTHFR, including the impact of phosphorylation on AdoMet-dependent inhibition.
Topics: Methylenetetrahydrofolate Reductase (NADPH2); S-Adenosylmethionine; Allosteric Regulation; Chaetomium; Phosphorylation; Humans; Crystallography, X-Ray; Models, Molecular; Flavin-Adenine Dinucleotide
PubMed: 38886362
DOI: 10.1038/s41467-024-49327-5 -
ACS Omega Jun 2024Schistosomiasis is a neglected disease of poverty that affects over 200 million people worldwide and relies on a single drug for therapy. The cathepsin B1 cysteine...
Schistosomiasis is a neglected disease of poverty that affects over 200 million people worldwide and relies on a single drug for therapy. The cathepsin B1 cysteine protease (SmCB1) of has been investigated as a potential target. Here, a structure-based pharmacophore virtual screening (VS) approach was used on a data set of approved drugs to identify potential antischistosomal agents targeting SmCB1. Pharmacophore (PHP) models underwent validation through receiver operating characteristics curves achieving values >0.8. The data highlighted riboflavin (RBF) as a compound of particular interest. A 1 μs molecular dynamics simulation demonstrated that RBF altered the conformation of SmCB1, causing the protease's binding site to close around RBF while maintaining the protease's overall integrity. RBF inhibited the activity of SmCB1 at low micromolar values and killed the parasite in vitro. Finally, in a murine model of infection, oral administration of 100 mg/kg RBF for 7 days significantly decreased worm burdens by ∼20% and had a major impact on intestinal and fecal egg burdens, which were decreased by ∼80%.
PubMed: 38882094
DOI: 10.1021/acsomega.4c03376 -
Journal of Biomedical Optics Jun 2024To enable non-destructive longitudinal assessment of drug agents in intact tumor tissue without the use of disruptive probes, we have designed a label-free method to...
SIGNIFICANCE
To enable non-destructive longitudinal assessment of drug agents in intact tumor tissue without the use of disruptive probes, we have designed a label-free method to quantify the health of individual tumor cells in excised tumor tissue using multiphoton fluorescence lifetime imaging microscopy (MP-FLIM).
AIM
Using murine tumor fragments which preserve the native tumor microenvironment, we seek to demonstrate signals generated by the intrinsically fluorescent metabolic co-factors nicotinamide adenine dinucleotide phosphate [NAD(P)H] and flavin adenine dinucleotide (FAD) correlate with irreversible cascades leading to cell death.
APPROACH
We use MP-FLIM of NAD(P)H and FAD on tissues and confirm viability using standard apoptosis and live/dead (Caspase 3/7 and propidium iodide, respectively) assays.
RESULTS
Through a statistical approach, reproducible shifts in FLIM data, determined through phasor analysis, are shown to correlate with loss of cell viability. With this, we demonstrate that cell death achieved through either apoptosis/necrosis or necroptosis can be discriminated. In addition, specific responses to common chemotherapeutic treatment inducing cell death were detected.
CONCLUSIONS
These data demonstrate that MP-FLIM can detect and quantify cell viability without the use of potentially toxic dyes, thus enabling longitudinal multi-day studies assessing the effects of therapeutic agents on tumor fragments.
Topics: Animals; Mice; Cell Survival; Microscopy, Fluorescence, Multiphoton; Apoptosis; Flavin-Adenine Dinucleotide; NADP; Cell Line, Tumor; Optical Imaging
PubMed: 38881557
DOI: 10.1117/1.JBO.29.S2.S22709 -
Talanta Jun 2024The detection of trypsin and its inhibitors is important for both clinical diagnosis and disease treatment. Abnormal trypsin activity affects pancreatic function and...
The detection of trypsin and its inhibitors is important for both clinical diagnosis and disease treatment. Abnormal trypsin activity affects pancreatic function and leads to corresponding pathological changes in the body. Therefore, the study presented a riboflavin-induced photo-ATRP electrochemical assay of trypsin activity and its inhibitor, including detection of trypsin activity in real urine samples. Experiments were performed on indium tin oxide (ITO) electrodes modified with sulfhydryl groups of 3-mercaptopropionic acid, and target trypsin-specific cleavage of BSA-Au nanocluster (BSA-Au NCs) was followed by the modification of Au NCs to the electrodes using Au-S. The Au NCs immobilized monodeoxy-monomercapto-β-cyclodextrin@adamantan-2-amine (SH-β-CD@2-NH-Ada) host-guest inclusion complexes to the electrode surfaces via Au-S. In a two-component photo-initiator system consisting of riboflavin as an initiator and ascorbic acid (AA) as a mild reducing agent under mild blue light radiation, a large number of electroactive substances were grafted onto the electrode surface to generate electrochemical signals. In addition, we have successfully realized the detection of clinical drug inhibitors of trypsin. The detection limit of the system is as low as 0.0024 ng/mL, which much littler than the average standard of trypsin in the patient's urine or serum. It's worth noting that this work will provide researchers with a different route to design electrochemical sensors based on non-covalent recognition strategies.
PubMed: 38876027
DOI: 10.1016/j.talanta.2024.126386